Rozprawy doktorskie: „Sodium Ion Conducting Materials”

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Naqash, Sahir Verfasser], Olivier [Akademischer Betreuer] Guillon i Jochen M. [Akademischer Betreuer] [Schneider. "Sodium ion conducting ceramics for sodium ion batteries / Sahir Naqash ; Olivier Guillon, Jochen Michael Schneider". Aachen : Universitätsbibliothek der RWTH Aachen, 2019. http://d-nb.info/1190040611/34.

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Naqash, Sahir [Verfasser], Olivier Akademischer Betreuer] Guillon i Jochen M. [Akademischer Betreuer] [Schneider. "Sodium ion conducting ceramics for sodium ion batteries / Sahir Naqash ; Olivier Guillon, Jochen Michael Schneider". Aachen : Universitätsbibliothek der RWTH Aachen, 2019. http://nbn-resolving.de/urn:nbn:de:101:1-2019070807164971884045.

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LONGONI, GIANLUCA. "Investigation of Sodium-ion Battery Materials". Doctoral thesis, Università degli Studi di Milano-Bicocca, 2017. http://hdl.handle.net/10281/153278.

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La tecnologia delle batterie Sodio-ione ha negli ultimi tempi suscitato una crescente attenzione da parte della comunità scientifica mondiale grazie al fatto di poter rappresentare una valida alternativa alla tecnologia Litio-ione, più sostenibile dal punto di vista ambientale ed economico. Il lavoro di Dottorato è stato principalmente dedicato alla ricerca di materiali attivi per batterie Sodio ione. I materiali presi in considerazione, sia catodici che anodici, sono stati indagati ponendo particolare attenzione ai limiti e difficolta pratiche che gli stessi possono manifestare nei confronti dell'intercalazione di sodio. Tra questi sono stati considerati: i) la valutazione della diffusione di Na+ in una struttura host intercalante, ii) e prodotti, gli intermedi e la reversibilità di reazione di conversione di ossidi dei metalli di transizione, iii) gli effetti delle proprietà cristalline dei materiali sulle performance elettrochimiche e iv) le caratteristiche chimico-fisiche caratterizzanti la generale stabilità di un materiale funzionale per batterie. Durante il lavoro di tesi è stato perpetrato un continuo parallelismo tra le caratteristiche morfologiche e strutturali e le performance elettrochimiche, ottenendo infine una dettagliata visione di molteplici classi di materiali attivi per sodio-ione. Ciò ha reso necessario un approccio inter-disciplinare in cui ad avanzate tecniche analitiche di tipo elettrochimico, è stato affiancato un approccio più specificatamente ingegneristico dei materiali stessi, al fine di evidenziare le correlazione proprietà-struttura. Tra le classi di materiali attivi investigate un ruolo di primaria importanza è stato riservato a materiali ad intercalazione catodici e materiali a conversione basati su ossidi di metalli di transizione. I primi, tipicamente materiali con struttura cristallina lamellare di natura ossidica, o a base di fosfati e pirofosfati, promuovono l’intercalazione di sodio con cinetiche veloci e con molteplici geometrie e pattern assunti dai cationi intercalati. I materiali a conversione invece permettono di ottenere lo stoccaggio energetico tramite reazione chimiche spontanee che avvengono tra materiale attivo e lo ione sodio. Paragonati a materiali ad intercalazione, i materiali a conversione presentano molteplici problematiche, tra cui: i) la variazione di volume considerevole che accompagna la reazione di conversione che introduce stress meccanici considerevoli e porta alle tipiche frammentazioni d’elettrodo e ii) processi irreversibili che solitamente corredano la reazione di conversione. Un aspetto che rende tali materiali meritevoli di essere studiati è la loro capacità di stoccare elevate quantità di sodio rendendoli capaci di capacità specifiche teoriche straordinarie (> 800 mAh/g). Tutti questi aspetti sono stati affrontati e tenuti in profonda considerazione al fine di mettere a punto un materiali a conversione anodica nano-strutturato a base di Co3O4 che rappresentasse una valida soluzione al problema di perfezionamento delle batterie sodio-ione. Assieme a materiali anodici, è stato altresì condotto lo studio di materiali catodici caratterizzati da elevate performance ma bassi costi di sintesi. Lo studio preliminare del composito ad intercalazione Na2FeP2O7/MWCNT a condotto ad interessanti risultati legati ad estremamente veloci cinetiche di diffusione di sodio all’interno del network di canali del materiale e ad una generale stabilità durante la ciclazione. All’anatasio (TiO2) nano-crystallino sintetizzato ad-hoc è stata dedicata l’ultima parte del lavoro di ricerca. Tale lavoro ha permesso di confermare importanti correlazioni tra le caratteristiche cristalline superficiali dei nano-cristalli e i meccanismi di interazione con sodio attraverso meccanismi pseudocapacitivi; e significativi avanzamenti sono stati ottenuti nella definizione di tale meccanismo e nella messa a punto di un efficiente materiale anodico a basso costo.
Na-ion battery technology has recently aroused great interest among all the scientific community, as a valid and more environmentally friendly alternative to Li-ion batteries. The PhD research activity has been mostly devoted to the investigation of reliable active materials for sodium ion battery technology. All the investigated materials, either anode or cathode, have been investigated trying to highlight the major limits and difficulties connected to sodium intercalation and conversion reactions. Among these, some are: i)assessment of Na diffusion in an intercalating host structure, ii)products and reversibility of transition metal oxides conversion reactions, iii) effects of materials crystalline properties on electrochemical performances and iv) features influencing the overall stability of a functional material. In order to keep the most broad-based overview of the problem, it has been chosen to systematically start, for each species electrochemically investigated, from its synthesis and thorough chemical-physical characterization. Rather than a pure electrochemical analysis, a continuous parallelism between morphological features, structural characteristics and performances was encouraged, eventually obtaining a detailed overlook of different classes of active materials for sodium batteries. What has been screened all along the three year-long research period has been a comprehensive investigation of new generation electrochemically active materials for energy storage applications. This implied an inter-disciplinary work in which advanced electro-analytical techniques have been widely used to characterize inorganic compounds or ad-hoc synthesized composites keeping in mind precise structure-performance correlations. Among the investigated classes, a role of relevance has been reserved to intercalating cathode species and conversion anode materials. The former, typically layered transition metal oxides, phosphates and pyrophosphates, are capable of sodium cations insertion, with fast kinetics, between layers or inside channels generated from peculiar atoms arrangement. Conversion anode materials on the other hand, carries out the sodium storage via spontaneous chemical reactions with oxide-based material, such as Co3O4 or Fe2O3, a chalcogenide or a halide. Compared to intercalation materials, conversion ones are more challenging to deal with, due to the following difficulties: i)their not negligible volume change during conversion reaction and the correlated induced mechanical stresses leading to electrode fracturing and pulverization, ii)occurrence of irreversible and parasitic reactions and iii)material operating potentials is often too high (around 1.0 V vs. Na/Na+) and thus not suitable for being used as anode materials inside a sodium cell. A positive feature that makes these material worthy to be studied is the high sodium uptake they are able to bare, bestowing them high theoretical specific capacities (>800 mAh∙g-1). All these aspects have been tackled in designing a conversion anode that might constitute a valid solution toward a sodium secondary battery whole-cell assembly. Together with anode materials also a high-performing and low-cost cathode material has been investigated. The exploratory study of pyrophosphate-MWCNT composite intercalation material led to interesting results referred to fast kinetics and material reliability throughout the cycles. To TiO2 nanocrystals synthesis and crystalline appearance-electrochemical properties correlation has beeb dedicated an exhaustive analysis which allowed to achieve significative advancements in defining the sodium uptake mechanism for pseudo-capacitive oxide-based anode material for sodium-ion batteries.

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Campbell, A. G. "Electrical processes at metallic contacts to sodium ion conducting glass". Thesis, University of Edinburgh, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.378729.

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Nwafornso, Tochukwu. "Bismuth anode for sodium-ion batteries". Thesis, Uppsala universitet, Strukturkemi, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-449075.

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It is imperative to develop alternative battery technologies based on naturally abundant elements, with competitive performance as lithium-ion batteries. Sodium has a natural abundance 1000 times more than lithium with both lithium and sodium-ion batteries having similar chemistry. Sodium-ion batteries are potentially an alternative that can achieve such competitive performance, given that electrode and electrolyte materials of high rate and long-term electrochemical performance are being developed. This thesis investigates the rate capability and long-term performance of bulk bismuth electrodes containing varying carbon content. The electrodes were cycled in cells with glyme-based electrolytes: diglyme and tetraglyme. Scanning electron microscopy and energy dispersive spectroscopy showed the morphology and elemental mapping of pristine and cycled bismuth electrodes. The result demonstrates the evolving porosity as the electrode cycled. The galvanostatic cycling of half-cells showed two plateaus each for sodiation and desodiation. Also, two peaks are seen in cyclic voltammetry suggesting a two-phase reaction. When cycled between -0.6 to 0.6 V in a symmetrical cell, the bismuth electrode showed an appreciable rate capability at a current rate of 770 mA/g in diglyme. In tetraglyme, it showed a poor rate capability, even at a current rate of 308 mA/g. The rate performance in a full cell cycled between 0.1 to 3.2 V also showed a good rate capability at a current rate of 770 mA/g in diglyme. Tetraglyme showed poor rate capability at the same current rate. The capacity retention was higher in the symmetrical cells, with 79 % and 78 % capacity retention relative to the initial charge capacity after 100 cycles for diglyme and tetraglyme. At the same current rate and more than 70 cycles, the full cells showed capacity retention of 58 % in diglyme and 44.8 % in tetraglyme. The capacity retention varied slightly for the two different electrode composites. The superior performance in the symmetrical cell is due to the narrow voltage window. Evaluating the stability of the solid electrolyte interphase via galvanostatic cycling suggests some stability issues. The full cells showed growing resistance with an increasing number of cycles.

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Simpson, Michael Alan. "Synthesis and characterisation of potential ion conducting materials incorporating crown ethers". Thesis, Heriot-Watt University, 1997. http://hdl.handle.net/10399/690.

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Toumar, Alexandra Jeanne. "Phase transformations in layered electrode materials for sodium ion batteries". Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/111255.

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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2017.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 118-130).
In this thesis, I investigate sodium ion intercalation in layered electrode materials for sodium ion batteries. Layered metal oxides have been at the forefront of rechargeable lithium ion battery technology for decades, and are currently the state of the art materials for sodium ion battery cathodes in line for commercialization. Sodium ion intercalated layered oxides exist in several different host phases depending on sodium content and temperature at synthesis. Unlike their lithium ion counterparts, seven first row layered TM oxides can intercalate Na ions reversibly. Their voltage curves indicate significant and numerous reversible phase transformations during electrochemical cycling. These transformations arise from Na-ion vacancy ordering and metal oxide slab glide but are not well understood and difficult to characterize experimentally. In this thesis, I explain the nature of these lattice differences and phase transformations for O and P-type single-transition-metal layered systems with regards to the active ion and transition metal at hand. This thesis first investigates the nature of vacancy ordering within the O3 host lattice framework, which is currently the most widely synthesized framework for sodium ion intercalating oxides. I generate predicted electrochemical voltage curves for each of the Na-ion intercalating layered TM oxides using a high-throughput framework of density functional theory (DFT) calculations and determine a set of vacancy ordered phases appearing as ground states in all NaxMO₂ systems, and investigate the energy effect of stacking of adjacent layers. I also examine the influence of transition metal mixing and transition metal migration on the materials' thermodynamic properties. Recent work has established the P2 framework as a better electrode candidate structure type than O3, because its slightly larger interlayer spacing allows for faster sodium ion diffusion due to lower diffusion barriers. However, little has been resolved in explaining what stabilizing mechanisms allow for the formation of P-type materials and their synthesis. This work therefore also investigates what stabilizes P2, P3 and O3 materials and what makes them synthesizable at given synthesis conditions, both for the optimization of synthesis techniques and for better-guided material design. It is of further interest to understand why some transition metal oxide systems readily form P2 or P3 compounds while others do not. I investigate several possible stabilizing mechanisms that allow P-type layered sodium metal oxides to by synthesized, and relate these to the choice of transition metal in the metal oxide structure. Finally, this work examines the difficulty of sodium ion intercalation into graphite, which is a commonly used anode material for lithium ion batteries, proposing possible reasons for why graphite does not reversibly intercalate sodium ions and why cointercalation with other compounds is unlikely. This thesis concludes that complex stabilizing mechanisms that go beyond simple electrostatics govern the intercalation of sodium ions into layered systems, giving it advantages and disadvantages over lithium ion batteries and outlining design principles to improve full-cell sodium ion battery materials.
by Alexandra Jeanne Toumar.
Ph. D.

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Li, Xianji. "Metal nitrides as negative electrode materials for sodium-ion batteries". Thesis, University of Southampton, 2015. https://eprints.soton.ac.uk/374787/.

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Zhang, Ketian. "Mixed ion and electron conducting polymer composite membranes for artificial photosynthesis". Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/121607.

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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2019
Cataloged from PDF version of thesis.
Includes bibliographical references.
Inspired by the fact that OH- has a very high mobility in water, highly conductive OH⁻conducting membranes were developed for alkaline water electrolysis. The membranes were semi-interpenetrating networks of crosslinked poly(vinyl alcohol) (PVA) and a polycation miscible with PVA. It is analogous to aqueous strong base solution. The polycation is a OH- containing polymer; PVA solvates this polycation and facilitates the ion conduction via Grotthuss mechanism. The membrane with proper composition has an exceptionally high OH⁻ conductivity of 151 mS/cm, 6.51 times as high as the commercial membrane Neosepta AHA. At the same time, the hydrogen bonds and covalent crosslinks in the system give this membrane a high tensile strength of 41 MPa in the wet state, 46% higher than the Neosepta AHA membrane. Insight in the ion conduction mechanism was gained by spectroscopic studies and the measurement of OH- conduction activation energy.
This material system is also highly anion perm-selective, a feature critical to sustaining the pH gradient in bipolar membrane based artificial photosynthesis devices. A highly transparent mixed proton and electron conducting membrane was developed. The Nafion and reduced graphene oxide (rGO) were chosen as the proton conducting polymer matrix and the electrically conductive filler respectively. The filler has a high aspect ratio. As predicted by simulations, it will have low percolation threshold if homogeneously dispersed. To achieve this homogeneity, water-aided mixing was employed followed by fast freezing in liquid nitrogen. Though rGO is a light absorber, the extremely low percolation threshold (0.1%) allows us to achieve sufficient electrical conductivity with only a small volume fraction of rGO. Therefore, the membrane was highly transparent in addition to its ability to conduct both electrons and protons.
Detailed modeling of the energy loss from conduction, light absorption, and gas crossover was conducted, showing that this material system is promising for the artificial photosynthesis application.
by Ketian Zhang.
Ph. D.
Ph.D. Massachusetts Institute of Technology, Department of Materials Science and Engineering

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Yue, Zhilian. "Synthesis of thermotropic cellulose derivatives and their behaviour as ion conducting materials". Thesis, Heriot-Watt University, 2002. http://hdl.handle.net/10399/492.

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FIORE, MICHELE. "Nanostructured Materials for secondary alkaline ion batteries". Doctoral thesis, Università degli Studi di Milano-Bicocca, 2020. http://hdl.handle.net/10281/262348.

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Thanks to their superior energy and power density, lithium-ion batteries (LIBs) currently dominate the market of power sources for portable devices. The economy of scale and engineering optimizations have driven the cost of LIBs below the 200 $/KWh at the pack level. This catalyzed the market penetration of electric vehicles and made them a viable candidate for stationary energy storage. However, the rapid market expansion of LIBs raised growing concerns about the future sustainability of this technology. In particular, lithium and cobalt supplies are considered vulnerable, primarily because of the geopolitical implications of their high concentration in only a few countries. In the search for the next generation secondary batteries, known as post-lithium ion batteries, candidates that do not use rare metals have been extensively investigated in the last 10 years. Sodium-ion batteries (SIBs) attracted considerable attention thanks to the high abundance of the precursors and wide distribution of sodium on the earth's crust. As a matter of fact, as it will be pointed out during the dissertation, it is not straightforward to allocate the reduction of the price of the alkaline ion precursors to the reduction of the battery price. However, the difficulties in the supply of raw materials for LIBs, such as shortages in lithium carbonates and cobalt ores, could make lithium and cobalt-free systems, such as SIBs, attractive and cost-competitive alternatives. Compared to other, more exotic chemistries including Ca2+, Mg2+ and Al3+ batteries, SIBs are nowadays considered one as the most promising alternative to LIBs. Despite the extensive research, anode materials for SIBs still represent a serious problem for the commercial exploitation of this technology. Accordingly, the doctoral research on SIBs has been focused on anode materials. In particular, the attention was directed towards conversion oxides. Compared to intercalation materials, conversion-based ones have higher capacities but are more challenging to deal with because of the high volume variation during cycling. This challenge was addressed by material's nanostructuring and morphology control which proved to significantly reduce the pulverization of the active material. Different anode candidates have been studied during the doctoral work. Cobalt oxide nanofibers have been here explored as a first prototype for conversion materials in sodium ion batteries. The sodiation-desodiation mechanism is analyzed by means of ex situ XRD which led to a deeper understanding of the conversion reaction in SIBs. A cost-effective and environmentally benign alternative based on iron oxide is then considered. The limits of iron (III) oxide are tackled by combining the advantages of the nanostructuring and the doping with an aliovalent element. Si-doped Fe2O3 nanofibers are synthesized via an easy scalable process based on the electrospinning method. It is found that Si-addition improves the transport properties as well as induces changes in the crystal structure and morphology. In the final section of the thesis, potassium-ion batteries (KIBs) are examined as a promising alternative to sodium ion batteries. KIBs exhibit all the benefits of SIBs, with the additional advantage that graphite, can reversibly accommodate K-ions. On the positive side, Potassium manganese hexacyanoferrate (KMnHCF), has been reported to provide high operating voltages and satisfactory capacity retention. The proposed research activity presents the use of an ionic liquid based electrolyte compatible with the most promising anode and cathode for KIBs. In addition, a high-throughput optimization of the KMnHCF synthesis is reported. The selected candidates are then fully characterized, and their electrochemical properties investigated. The optimized material exhibits the highest ever reported coulombic efficiency for the KMHCF. This find, opens up the possibility of highly efficient, high energy potassium ion batteries.
Thanks to their superior energy and power density, lithium-ion batteries (LIBs) currently dominate the market of power sources for portable devices. The economy of scale and engineering optimizations have driven the cost of LIBs below the 200 $/KWh at the pack level. This catalyzed the market penetration of electric vehicles and made them a viable candidate for stationary energy storage. However, the rapid market expansion of LIBs raised growing concerns about the future sustainability of this technology. In particular, lithium and cobalt supplies are considered vulnerable, primarily because of the geopolitical implications of their high concentration in only a few countries. In the search for the next generation secondary batteries, known as post-lithium ion batteries, candidates that do not use rare metals have been extensively investigated in the last 10 years. Sodium-ion batteries (SIBs) attracted considerable attention thanks to the high abundance of the precursors and wide distribution of sodium on the earth's crust. As a matter of fact, as it will be pointed out during the dissertation, it is not straightforward to allocate the reduction of the price of the alkaline ion precursors to the reduction of the battery price. However, the difficulties in the supply of raw materials for LIBs, such as shortages in lithium carbonates and cobalt ores, could make lithium and cobalt-free systems, such as SIBs, attractive and cost-competitive alternatives. Compared to other, more exotic chemistries including Ca2+, Mg2+ and Al3+ batteries, SIBs are nowadays considered one as the most promising alternative to LIBs. Despite the extensive research, anode materials for SIBs still represent a serious problem for the commercial exploitation of this technology. Accordingly, the doctoral research on SIBs has been focused on anode materials. In particular, the attention was directed towards conversion oxides. Compared to intercalation materials, conversion-based ones have higher capacities but are more challenging to deal with because of the high volume variation during cycling. This challenge was addressed by material's nanostructuring and morphology control which proved to significantly reduce the pulverization of the active material. Different anode candidates have been studied during the doctoral work. Cobalt oxide nanofibers have been here explored as a first prototype for conversion materials in sodium ion batteries. The sodiation-desodiation mechanism is analyzed by means of ex situ XRD which led to a deeper understanding of the conversion reaction in SIBs. A cost-effective and environmentally benign alternative based on iron oxide is then considered. The limits of iron (III) oxide are tackled by combining the advantages of the nanostructuring and the doping with an aliovalent element. Si-doped Fe2O3 nanofibers are synthesized via an easy scalable process based on the electrospinning method. It is found that Si-addition improves the transport properties as well as induces changes in the crystal structure and morphology. In the final section of the thesis, potassium-ion batteries (KIBs) are examined as a promising alternative to sodium ion batteries. KIBs exhibit all the benefits of SIBs, with the additional advantage that graphite, can reversibly accommodate K-ions. On the positive side, Potassium manganese hexacyanoferrate (KMnHCF), has been reported to provide high operating voltages and satisfactory capacity retention. The proposed research activity presents the use of an ionic liquid based electrolyte compatible with the most promising anode and cathode for KIBs. In addition, a high-throughput optimization of the KMnHCF synthesis is reported. The selected candidates are then fully characterized, and their electrochemical properties investigated. The optimized material exhibits the highest ever reported coulombic efficiency for the KMHCF. This find, opens up the possibility of highly efficient, high energy potassium ion batteries.

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Dacek, Stephen Thomas III. "First principles investigation and design of fluorophosphate sodium-ion battery cathodes". Thesis, Massachusetts Institute of Technology, 2016. http://hdl.handle.net/1721.1/109684.

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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2016.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 119-140).
Lithium-ion batteries are currently the most widely used consumer energy storage technology. Recently, lithium-ion batteries have been evaluated for use in mitigating the intermittent power supply of leading renewable energy technologies, thereby enabling their use on the electric grid. In order to facilitate the widespread adoption of electric vehicles and renewable energy technologies, the energy-densities, lifetimes, and cost of batteries must be improved. Due to concerns over long-term lithium availability, sodium-ion batteries are currently being investigated as an alternative to lithium-ion batteries in grid-level applications. In this thesis, we use ab inritio methods to characterize th high-voltage sodium-ion fluorophosphate with formula NaxV2(PO4)2O2yF3-2y as an alternative chemistry to Li-ion batteries. In Chapter 3 we investigate the sodium-extraction limitations in the NaxV2(PO4)2O2yF3-2 fluorophosphate. Specifically, we focus on the potential to reversibly extract sodium beyond the 1 by Stephen Thomas Dacek, III
Ph. D.

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Park, Jun-Young. "Solid-state electrochemical properties of oxygen-ion conducting ceramic materials and their applications". [Gainesville, Fla.] : University of Florida, 2004. http://purl.fcla.edu/fcla/etd/UFE0006660.

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Zhang, Huang [Verfasser], i S. [Akademischer Betreuer] Passerini. "Polyanionic cathode materials for sodium-ion batteries / Huang Zhang ; Betreuer: S. Passerini". Karlsruhe : KIT-Bibliothek, 2019. http://d-nb.info/1178528162/34.

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LI, TAO. "The Study of Various Anode Materials for Sodium (or Lithium)-Ion Batteries". Doctoral thesis, Università degli studi di Genova, 2019. http://hdl.handle.net/11567/939856.

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room-temperature sodium-ion batteries (NIBs or SIBs) have raised a great deal of attention for grid-level applications considering the sustainability advantages of NIBs. Significant progress has been made for NIB cathodes by adapting the knowledge learned on lithium-ion batteries (LIBs). Simultaneously, numerous attempts have been made to find suitable anodes for NIBs, however, the research to improve NIB technologies rema ns a challenge. This thesis presents fundamental studies of various anode materials for NIBs from different aspects. Surface and interface engineering of nanostructured anatase TiO2 anode through Al2O3 surface modification and wise electrolyte selection is conducted. The results show that Al2O3 coating provides beneficial effects to the TiO2-based anodes and the modified TiO2 exhibits significant improvements in cycling performance using electrolyte with binary ethylene carbonate (EC) and propylene carbonate (PC) solvent mixture without the need of the commonly used fluoroethylene carbonate (FEC) additive. The achieved excellent electrochemical performance (a high reversible capacity of 188.1 mAh g−1 at 0.1C after 50 cycles, good rate capability up to 5C, and long-term cycling performance for 650 cycles at a high rate of 1C) can be ascribed to the synergistic effects of surface and interface engineering enabling the formation of a stable and highly ionic conductive interface layer in EC:PC based electrolyte which combines the native SEI film and an ‘artificial’ SEI layer of irreversibly formed Na−Al−O. A dual-modification approach of Mo doping combined with AlF3 coating is also introduced to enhance the sodium storage activity of anatase TiO2. The Mo-doped anatase TiO2 synthesized by a simple co-precipitation method delivers an enhanced reversible capacity compare to pristine TiO2 (139.8 vs. 100.7 mAh g−1 at 0.1C after 50 cycles) due to enhanced electronic/ionic conductivity. Via further coating AlF3 using a modified solid-state method, a much higher reversible capacity of 178.9 mAh g−1 with good cycle stability and excellent rate capabilities up to 10C can be finally obtained. The experimental results indicate that AlF3 surface coating could effectively reduce solid electrolyte interfacial resistance, enhance electrochemical reactivity at the surface/interface region, and lower polarization during cycling. As for alloy-type anode of Sn with high theoretical capacity of 847 mAh g−1 but experiences a high volume expansion of 420% upon sodiation, we carry out a fundamental study of the degradation mechanisms that occur in Sn during sodiation-desodiation by employing a Sn thick film as the anode. Electron microscopy reveals new deformation mechanisms, as multiple Sn whiskers nucleate on the surface of the Sn, while pores form within the Sn (over the Na-ion penetration distance) after electrochemical cycling. These mechanisms are in addition to the dry lake-bed fracture that is also observed. Such whiskers and pores may be more-subtle at the nanoscale, and therefore have not been reported for sub-micron Sn particles in porous electrodes. The simplified planar geometry of the Sn sheet allows to dispense with the influence of the binder and carbon additives that are required in porous electrodes and the implementation of the Randles-Sevick equation provides a first experimental estimate for the diffusion coefficient of Na+ in Sn as 6.45×10−12 cm2 s−1. Finally, we explore facile synthesis of carbon materials from low cost carbon source of CaC2 using a novel sulfur-based thermo-chemical etching technique. Comprehensive analysis using X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and N2 adsorption−desorption isotherms, reveals a highly graphitized mesoporous structure for the CaC2-derived carbon with a specific surface area of 159.5 m2 g−1. Microscopic analysis displays micron-scale mesoporous frameworks (4–20 μm) with a distinct layered structure along with agglomerates of highly graphitized nanosheets (about 10 nm in thickness and 1–10 μm of lateral size). The application of the as-prepared carbon materials as anode for NIBs and LIBs is also preliminarily studied.

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Richards, William D. (William Davidson). "Ab initio investigations of solid electrolytes for lithium- and Sodium-ion batteries". Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/108967.

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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Materials Science and Engineering, 2017.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 119-127).
Solid-state electrolytes have the potential to dramatically improve the safety and longevity of state-of-the-art battery technology by replacing the flammable organic electrolytes currently employed in Li-ion batteries. Recent advances in the development of new thiophosphate electrolytes have reenergized the field by achieving room temperature conductivities exceeding those liquid electrolytes, but a number of practical challenges to their widespread adoption still exist. This thesis applies ab initio computational methods based on density functional theory to investigate the structural origins of high conductivity in ionic conductor materials and provides a thermodynamic explanation of why the integration of these newly developed thiophosphates into high-rate cells has proven difficult in practice, often resulting in high interfacial resistance. As a result of these computational investigations, we report the prediction and synthesis of a new high performance sodium-ion conducting material: NaioSnP 2S 12, with room temperature ionic conductivity of 0.4 mS cm-1, which rivals the conductivity of the best sodium sulfide solid electrolytes to date. We computationally investigate the variants of this compound where Sn is substituted by Ge or Si and find that the latter may achieve even higher conductivity. We then investigate the relationship between anion packing and ionic transport in fast Li-ion conductors, finding that a bcc-like anion framework is desirable for achieving high ionic conductivity, and that this anion arrangement is present in a disproportionately high number of known Li-conducting materials, including Na10SnP2S12 and its structural analog Li10GeP2S2 . Using this bcc anion lattice as a screening criterion, we show that the I4 material LiZnPS4 also contains such a framework and has the potential for very high ionic conductivity. While the stoichiometric material has poor ionic conductivity, engineering of its composition to introduce interstitial lithium defects is able to exploit the low migration barrier of the bcc anion structure. Thermodynamic calculations predict a solid-solution regime in this system that extends to x = 0.5 in Li1+2xZn-xPS 4 , thus it may yield a new ionic conductor with exceptionally high lithium-ion conductivity, potentially exceeding 50 mS cm- 1 at room temperature. Finally, we develop a computational methodology to examine the thermodynamics of formation of resistive interfacial phases through mixing of the electrode and electrolyte. The results of the thermodynamic model of interfacial phase formation are well correlated with experimental observations and battery performance, and predict that thiophosphate electrolytes have especially high reactivity with high voltage oxide cathodes and a narrow electrochemical stability window. We also find that a number of known electrolytes are not inherently stable, but react in situ with the electrode to form passivating but ionically conducting barrier layers.
by William D. Richards.
Ph. D.

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Wood, Stephen. "Computer modelling studies of new electrode materials for rechargeable batteries". Thesis, University of Bath, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.687357.

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Developing a sustainable energy infrastructure for the 21st century requires the large scale development of renewable energy resources. Fully exploiting these inherently intermittent supplies will require advanced energy storage technologies, with rechargeable Li-ion and Na-ion batteries considered highly promising for both vehicle electrification and grid storage applications. However, the performance required of battery materials has not been achieved, and significant improvements are needed. Modern computational techniques allow the elucidation of structure-property relationships at the atomic level and are valuable tools in providing fundamental insights into novel materials. Therefore, in this thesis a combination of atomistic simulation and ab initio density functional theory (DFT) techniques have been used to study a number of potential battery cathode materials. Firstly, Na2FePO4F and NaFePO4 are interesting materials that have been reported recently as attractive positive electrodes for Na-ion batteries. Here, we report their Na-ion conduction behaviour and intrinsic defect properties using atomistic simulation methods. Na+ ion conduction in Na2FePO4F is predicted to be two-dimensional (2D) in the interlayer plane. Na ion migration in NaFePO4 is restricted to the [010] direction along a curved trajectory, leading to quasi-1D Na+ diffusion. Furthermore, Na/Fe antisite defects are predicted to have a lower formation energy in NaFePO4 than Na2FePO4F. The higher probability of tunnel occupation with a relatively immobile Fe2+ cation - along with a greater volume change on redox cycling - contributes to the poor electrochemical performance of NaFePO4. Secondly, work on the Na2FePO4F system is extended to include investigation of the surface structures and energetics. The equilibrium morphology is found to be essentially octagonal, compressed slightly along the [010] direction, and is dominated by the (010), (021), (122) and (110) surfaces. The calculated growth morphology is a more ``rod-like'' nanoparticle, with the (021), (023), (110) and (112) planes predominant. The (010) surface lies parallel to the Na layers in the ac plane and is unlikely to facilitate Na+ intercalation. As such, its prominence in the equilibrium morphology, and absence from the growth morphology, suggests nanoparticles synthesised in a kinetically limited regime should provide higher rate performance than those synthesised in close to equilibrium conditions. Surface redox potentials for Na2FePO4F derived using DFT vary between 2.76 - 3.37 V, in comparison to a calculated bulk cell voltage of 2.91 V. Most significantly, the lowest energy potentials are found for the (130) and (001) planes suggesting that upon charging Na+ will first be extracted from these surfaces, and inserted lastly upon discharging. Thirdly, the mixed phosphates Na4M3(PO4)2P2O7 (M=Fe, Mn, Co, Ni) are explored as a fascinating new class of materials reported to be attractive Na-ion cathodes, displaying low volume changes upon cycling indicative of long lifetime operation. Key issues surrounding intrinsic defects, Na-ion migration mechanisms and voltage trends have been investigated through a combination of atomistic energy minimisation, molecular dynamics and DFT simulations. The MD results suggest Na+ diffusion extends across a 3D network of migration pathways with an activation barrier of 0.20-0.24 eV, and diffusion coefficients (DNa) of 10-10-10-11 cm2s-1 at 325 K, suggesting high rate capability. The cell voltage trends, explored using DFT methods, indicate that doping the Fe-based cathode with Ni can significantly increase the voltage, and hence energy density. Finally, DFT simulations of K+-stabilised α-MnO2 have been combined with aberration corrected-STEM techniques to study the surface energetics, particle morphologies and growth mechanism. α-K0.25MnO2 grown through a hydrothermal synthesis method is found to produce primary nanowires with preferential growth along the [001] direction. Primary nanowires attach through a shared (110) interface to form larger secondary nanowires. This is in agreement with DFT simulations with the {100}, {110} and {211} surfaces displaying the lowest surface energies. The ranking of surface energies is driven by Mn coordination environments and surface relaxation. The calculated equilibrium morphology of α-K0.25MnO2 is consistent with the observed primary nanowires from high resolution electron microscopy images.

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Dou, Xinwei [Verfasser], i S. [Akademischer Betreuer] Passerini. "Hard Carbon Anode Materials for Sodium-ion Batteries / Xinwei Dou ; Betreuer: S. Passerini". Karlsruhe : KIT-Bibliothek, 2019. http://d-nb.info/1179963695/34.

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Posch, P., P. Bottke, M. Wilkening i I. Hanzu. "Hydrothermally Synthesized Nanostructured Sodium Titanates as Negative Electrode Materials for Na-Ion Batteries". Diffusion fundamentals 21 (2014) 22, S.1, 2014. https://ul.qucosa.de/id/qucosa%3A32432.

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Liang, Wenfeng. "Metal Organic Composites Derived Tin Dioxide/C Nanoparticles For Sodium-Ion Battery". University of Akron / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1460304081.

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21

Weldekidan, Ephrem Terefe. "Design of lithium ion conducting porous hybrid materials for the development of solid Li-battery electrolytes". Thesis, Aix-Marseille, 2019. http://www.theses.fr/2019AIXM0707.

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Dans ce travail, des matériaux hybrides polymères-silice poreuse sous forme de poudre et de film mince ont été synthétisés et caractérisés. L'étude préliminaire de leurs conductivité ionique Li+ a également été réalisée. Les poudres hybrides ont été synthétisées par voie sol-gel en utilisant des triblocs classiques (Pluronic, P123) et des diblocs copolymères amphiphiles bifonctinels fabriqués en laboratoire comme agents dirigeant la structure (SDA). Dans le premier cas, la modification post-synthétique a été utilisée pour fonctionnaliser la surface des pores de la silice avec du PEO. Dans un second temps, la fonctionnalisation de la surface des pores avec le bloc hydrophile (PEO) a été réalisée par extraction du bloc hydrophobe. Des films de silice avec des mésocanaux ordonnés de manière hexagonale et orientés verticalement ont été synthétisés sur la surface de l'électrode via un procédé d'auto-assemblage électro-assisté dans des conditions hydrodynamiques. Les films formés sont mésoporeux (3 nm de diamètre) et entièrement accessibles. Un film de 660 nm d'épaisseur a été obtenu en 200 secondes. Ce film a été fonctionnalisé avec du PEO puis du sel de lithium par le biais d'une méthode d'imprégnation en solution. La conductivité ionique des matériaux hybrides a été étudiée après la mise en forme de la poudre sous forme de pastille ou de film directement formé à la surface de l'électrode. Les résultats montrent la conductivité des ions Li+ apportée aux matériaux. Les pastilles ont une porosité interparticulaire de 40% et le remplissage avec l’électrolyte polymère a un effet positif sur l’optimisation de la conductivité des pastilles
In this work, porous polymer-silica hybrid materials as a powder and thin film are synthesized and characterized. The preliminary study of their Li+ ionic conductivity properties are carried out as well. Here, the polymer electrolyte is embedded in silica matrix - polymer-in-ceramic approach. The hybrid powders are synthesized through sol-gel using conventional triblock (Pluronic, P123) and laboratory made bifunctional diblock amphiphilic copolymers as structure directing agents (SDA). In the first case, post-synthetic modification is used to functionalize the pore surface of silica with PEO. The second allowed to direct functionalization the pore surface with hydrophilic block (PEO) through extraction of hydrophobic block. Particle-free mesoporous silica films with hexagonally ordered and vertically oriented mesochannels are synthesized on electrode surface via electro-assisted self-assembly method under hydrodynamic condition. The resulting films are mesoporous (a diameter of 3 nm) and fully accessible. A film with thickness of 660 nm was grown in 200 s, and functionalized with PEO and then lithium salt through solution impregnation method. The ionic conductivity properties of hybrids were performed after shaping the powder as a pellet or with the hybrid film directly formed on the electrode surface. The results showed that the Li+ conductivity brought to the materials. The pellets have 40 % interparticle porosity and filling this with polymer electrolyte has positive effect on optimizing conductivity of the pellets (2.0 x 10-7 Scm-1 for 35 % filling and 6.8 x 10-7 Scm-1 for 100% filling at 25 °C)

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Han, Ruixin. "SYNTHESIS, AND STRUCTURAL, ELECTROCHEMICAL, AND MAGNETIC PROPERTY CHARACTERIZATION OF PROMISING ELECTRODE MATERIALS FOR LITHIUM-ION BATTERIES AND SODIUM-ION BATTERIES". UKnowledge, 2018. https://uknowledge.uky.edu/chemistry_etds/90.

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Iron oxides, have been widely studied as promising anode materials in lithium-ion batteries (LIBs) for their high capacity (≈ 1000 mA h g-1 for Fe2O3 and Fe3O4,), non-toxicity, and low cost. In this work, β-FeOOH has been evaluated within a LIB half-cell showing an excellent capacity of ≈ 1500 mA h g-1 , superior to Fe2O3 or Fe3O4. Reaction mechanism has been proposed with the assistance of X-ray photoelectron spectroscopy (XPS). Various magnetic properties have been suggested for β-FeOOH such as superparamagnetism, antiferromagnetism and complex magnetism, for which, size of the material is believed to play a critical role. Here, we present a size-controlled synthesis of β-FeOOH nanorods. Co-existing superparamagnetism and antiferromagnetism have been revealed in β-FeOOH by using a Physical Property Measurement System (PPMS). Compared with the high price of lithium in LIBs, sodium-ion batteries (SIBs) have attracted increasing attentions for lower cost. Recent studies have reported Na0.44MnO2 to be a promising candidate for cathode material of SIBs. This thesis has approached a novel solid-state synthesis of Na0.44MnO2 whiskers and a nano-scaled open cell for in situ TEM study. Preliminary results show the first-stage fabrication of the cell on a biasing protochip.

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23

Dall'Agnese, Yohan. "Study of early transition metal carbides for energy storage applications". Thesis, Toulouse 3, 2016. http://www.theses.fr/2016TOU30025/document.

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La demande urgente d'innovations dans le domaine du stockage de l'énergie est liée au développement récent de la production d'énergie renouvelable ainsi qu'à la diversification des produits électroniques portables qui consomment de plus en plus d'énergie. Il existe plusieurs technologies pour le stockage et la conversion électrochimique de l'énergie, les plus notables étant les batteries aux ions lithium, les piles à combustible et les supercondensateurs. Ces systèmes sont utilisés de façon complémentaire des uns aux autres dans des applications différentes. Par exemple, les batteries sont plus facilement transportables que les piles à combustible et ont de bonne densité d'énergie alors que les supercondensateurs ont des densités de puissance plus élevés et une meilleure durée de vie. L'objectif principal de ces travaux est d'étudier les performances électrochimiques d'une nouvelle famille de matériaux bidimensionnel appelée MXène, en vue de proposer de nouvelles solutions pour le stockage de l'énergie. Pour y arriver, plusieurs directions ont été explorées. Dans un premier temps, la thèse se concentre sur les supercondensateurs dans des électrolytes aqueux et aux effets des groupes de surface. La seconde partie se concentre sur les systèmes de batterie et de capacités à ions sodium. Une cellule complète comportant une anode en carbone et une cathode de MXène a été développées. La dernière partie de la thèse présente l'étude des MXènes pour les supercondensateur en milieu organique. Une attention particulière est apportée à l'étude du mécanisme d'intercalation des ions entre les feuillets de MXène. Différentes techniques de caractérisations ont été utilisées, en particulier la voltampérométrie cyclique, le cyclage galvanostatique, la spectroscopie d'impédance, la microscopie électronique et la diffraction des rayons X
An increase in energy and power densities is needed to match the growing energy storage demands linked with the development of renewable energy production and portable electronics. Several energy storage technologies exist including lithium ion batteries, sodium ion batteries, fuel cells and electrochemical capacitors. These systems are complementary to each other. For example, electrochemical capacitors (ECs) can deliver high power densities whereas batteries are used for high energy densities applications. The first objective of this work is to investigate the electrochemical performances of a new family of 2-D material called MXene and propose new solutions to tackle the energy storage concern. To achieve this goal, several directions have been explored. The first part of the research focuses on MXene behavior as electrode material for electrochemical capacitors in aqueous electrolytes. The next part starts with sodium-ion batteries, and a new hybrid system of sodium ion capacitor is proposed. The last part is the study of MXene electrodes for supercapacitors is organic electrolytes. The energy storage mechanisms are thoroughly investigated. Different characterization techniques were used in this work, such as cyclic voltammetry, galvanostatic charge-discharge, electrochemical impedance spectroscopy, scanning electron microscopy and X-ray diffraction

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PIMENTA, MARCOS ASSUNCAO. "Transitions de phase a haute temperature et conduction ionique dans likso:(4) et composes apparentes". Orléans, 1987. http://www.theses.fr/1987ORLE2045.

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Etude par reflexion ir, diffusion brillouin et la mesure des conductivites electriques sur likso::(4), linaso::(4) et linh::(4)so::(4). Identification et analyse des differentes transitions; mise en evidence d'une relation etroite entre la mobilite cationique et les mouvements de rotationd es groupes sulfate. Observation d'une transition ordre-desordre a 435**(o)c, avec phse intermediaire a surstructure de basse symetrie, dans le cas de likso::(4)

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Ku, Esther M. (Esther Mei-Hua) 1973. "Synthesis, cation distribution, and disorder of fast-ion conducting pyrochlore oxides : a combined neutron and X-ray Rietveld analysis". Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/85268.

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Zhang, Yingchun. "Computational study of the transport mechanisms of molecules and ions in solid materials". [College Station, Tex. : Texas A&M University, 2006. http://hdl.handle.net/1969.1/ETD-TAMU-1711.

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GENTILE, ANTONIO. "MXene-based materials for alkaline-ion batteries: synthesis, properties, applications". Doctoral thesis, Università degli Studi di Milano-Bicocca, 2022. http://hdl.handle.net/10281/382748.

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La produzione sempre maggiore di dispositivi portatili e auto elettriche chiede al mercato di produrre dispositivi efficienti in grado di poter accumulare l’energia elettrica. Per questo tipo di tecnologie in cui la miniaturizzazione del dispositivo è essenziale, le batterie litio ione (LIBs) sono diventate il mezzo di accumulare energia. La ricerca su queste batterie è focalizzata ad ottenere dispositivi sempre più performanti con materiali elettrodici ad alte capacità gravimetriche e volumetriche. Accanto all’aspetto tecnologico, legato alla ottimizzazione dei materiali, vi è anche quello dell’approvvigionamento dei componenti attivi della batteria, tra tutti il litio. La problematica attualmente è affrontata studiando batterie con altri metalli alcalini (Na e K). Di questi dispositivi non esistono però materiali già standardizzati malgrado la ricerca, specialmente sulle batterie sodio ione (SIB), sia partita solo qualche anno più tardi rispetto quella delle LIB; per cui queste tecnologie oggi sono destinate ad affiancare quelle delle LIB per sopperire all’enorme richiesta di mercato di batterie per i veicoli del futuro. L’obbiettivo del presente lavoro è stato quello di sviluppare materiali anodici a base di MXene per ottenere efficienti anodi per batterie sodio e litio ione. I MXenes sono una famiglia di carburi di metalli di transizione con una struttura 2D che sembrerebbe promettente per l’intercalazione di diversi ioni grazie ad una grande flessibilità ed adattabilità strutturale nei confronti del tipo di ione intercalante. L’intercalazione degli ioni avviene con un meccanismo pseudocapacitivo per cui i materiali hanno capacità limitate, ma hanno grande stabilità elettrochimica su migliaia di cicli ed efficienze coulombiche prossime al 100%. La produzione di questo materiale avviene per etching in HF di un precursore chiamato MAX phase. Questo è il metodo più facile e veloce per ottenere il materiale in scala di laboratorio ma presenta numerose criticità quando i volumi vengono rapportati su scala industriale. Una gran parte del lavoro è stata dedicata allo studio della tecnica sintetica per ottenere MXenes per SIB riducendo o sostituendo HF nella sintesi chimica. I materiali sono stati caratterizzati con varie tecniche di caratterizzazioni strutturali, morfologiche ed elettrochimiche. Data la struttura 2D, che ricorda quella del grafene, un uso frequente in letteratura è quello della realizzazioni di nanocompositi per SIB e LIB, al fine di produrre materiali ad alta capacità, come richiesto nel mercato delle batterie. Sono stati quindi ottenuti dei nanocompositi a base di antimonio-MXene e ossido di stagno-MXene testati rispettivamente in SIB e LIB. Antimonio e ossido di stagno sono due materiale dalla elevata capacità teorica, quando usati come anodi in batterie, ma allo stesso tempo sono estremamente fragili e tendono a polverizzarsi nei processi di carica e scarica. Il MXene è servito da buffer per limitare o evitare la frattura e distacco delle leghe dalla superficie elettrodica
The ever-increasing production of portable devices and electric cars asks to the market to produce efficient devices that can store electrical energy. For these types of technologies, where device miniaturization is essential, lithium-ion batteries (LIBs) have become leaders as energy storage systems. The research on the lithium-ion batteries is focused to obtain more performing devices with high gravimetric and volumetric capacities of the electrode materials. In addition to the technological aspect, related to the optimization of materials, there is the supply chain of active components of the battery to consider, starting from lithium. At the moment, the problem is tackled by studying batteries with other alkaline metal ions, i.e. Na+ and K+. However, there are no standardized active materials for these devices, especially on sodium-ion batteries (SIBs), started only a few years later than that of LIBs; therefore, today these technologies are intended to support the LIBs in order to satisfy the enormous market demand of the batteries for the future vehicles. The goal of this work was to develop MXene-based anode materials to obtain efficient anodes for sodium and lithium-ion batteries. MXenes are a family of inorganic transition metal carbides, nitrides, and carbonitrides with a 2D structure that would seem promising for the intercalation of different ions due to a great flexibility and adaptability towards several intercalating ions. The ion intercalations occur by a pseudocapacitive mechanism whereby the materials have limited capacity, but they have great electrochemical stability over thousands of cycles and coulombic efficiencies near to 100%. The production of this material was done by HF etching of a precursor called MAX phase. This is the easiest and fastest method to obtain the material in laboratory scale, but it has many criticalities when the process has to be scale-up to industrial scale. A large part of this work was spent studying the synthetic technique to obtain MXenes for SIB by reducing or replacing HF in the chemical synthesis. The materials have been characterized by various techniques such as X-ray diffractometry, electron microscopy, X-ray photoelectron spectroscopy, etc., and by electrochemical tests, such as cyclic voltammetry and galvanostatic cycling. Thanks to the 2D structure, a common use of MXene in the literature is in nanocomposite syntheses for SIBs and LIBs, in order to produce high-capacity materials, as required in the battery market. Therefore, two nanocomposites based on antimony-MXene and tin oxide-MXene tested for SIB and for LIB respectively, were synthesized. Antimony and tin oxide are two materials with high theoretical capacity when used as anodes in batteries, but at the same time, they are extremely fragile and tend to pulverize during charging and discharging processes. MXene is used as a buffer to limit or prevent cracking and separation of alloys from the electrode surface.

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Brown, James Emery. "Advances in electrical energy storage using core-shell structures and relaxor-ferroelectric materials". Diss., Kansas State University, 2018. http://hdl.handle.net/2097/38779.

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Doctor of Philosophy
Department of Chemistry
Jun Li
Electrical energy storage (EES) is crucial in todays’ society owing to the advances in electric cars, microelectronics, portable electronics and grid storage backup for renewable energy utilization. Lithium ion batteries (LIBs) have dominated the EES market owing to their wide use in portable electronics. Despite the success, low specific capacity and low power rates still need to be addressed to meet the increasing demands. Particularly, the low specific capacity of cathode materials is currently limiting the energy storage capability of LIBs. Vanadium pentoxide (V₂O₅) has been an emerging cathode material owing to its low cost, high electrode potential in lithium-extracted state (up to 4.0 V), and high specific capacities of 294 mAh g⁻¹ (for a 2 Li⁺/V₂O₅ insertion process) and 441 mAh g⁻¹ (for a 3 Li⁺/V₂O₅ insertion process). However, the low electrical conductivities and slow Li⁺ ion diffusion still limit the power rate of V₂O₅. To enhance the power-rate capability we construct two core-shell structures that can achieve stable 2 and 3 Li⁺ insertion at high rates. In the first approach, uniform coaxial V₂O₅ shells are coated onto electrospun carbon nanofiber (CNF) cores via pulsed electrodeposition. The materials analyses confirm that the V₂O₅ shell after 4 hours of thermal annealing at 300 °C is a partially hydrated amorphous structure. SEM and TEM images indicate that the uniform 30 to 50 nm thick V₂O₅ shell forms an intimate interface with the CNF core. Lithium insertion capacities up to 291 and 429 mAh g⁻¹ are achieved in the voltage ranges of 4.0 – 2.0 V and 4.0 – 1.5 V, respectively, which are in good agreement with the theoretical values for 2 and 3 Li⁺/V₂O₅ insertion. Moreover, after 100 cycles, remarkable retention rates of 97% and 70% are obtained for 2 and 3 Li⁺/V₂O₅ insertion, respectively. In the second approach, we implement a three-dimensional (3D) core-shell structure consisting of coaxial V₂O₅ shells sputter-coated on vertically aligned carbon nanofiber (VACNF) cores. The hydrated amorphous microporous structure in the “as-deposited” V₂O₅ shells and the particulated nano-crystalline V₂O₅ structure formed by thermal annealing are compared. The former provides remarkably high capacity of 360 and 547 mAh g⁻¹ in the voltage range of 4.0 – 2.0 V and 4.0 – 1.5 V, respectively, far exceeding the theoretical values for 2 and 3 Li⁺/V₂O₅ insertion, respectively. After 100 cycles of 3 Li⁺/V₂O₅ insertion/extraction at 0.20 A g⁻¹ (~ C/3), ~ 84% of the initial capacity is retained. After thermal annealing, the core-shell structure presents a capacity of 294 and 390 mAh g⁻¹, matching well with the theoretical values for 2 and 3 Li⁺/V₂O₅ insertion. The annealed sample shows further improved stability, with remarkable capacity retention of ~100% and ~88% for 2 and 3 Li⁺/V₂O₅ insertion/extraction. However, due to the high cost of Li. alternative approaches are currently being pursued for large scale production. Sodium ion batteries (SIB) have been at the forefront of this endeavor. Here we investigate the sodium insertion in the hydrate amorphous V₂O₅ using the VACNF core-shell structure. Electrochemical characterization was carried out in the potential ranges of 3.5 – 1.0, 4.0 – 1.5, and 4.0 – 1.0 (vs Na/Na⁺). An insertion capacity of 196 mAh g-1 is achieved in the potential range of 3.5 – 1.0 V (vs Na/Na⁺) at a rate of 250 mA g⁻¹. When the potential window is shifted upwards to 4.0 – 1.5 V (vs Na/Na⁺) an insertion capacity of 145 mAh g⁻¹ is achieved. Moreover, a coulombic efficiency of ~98% is attained at a rate of 1500 mA g⁻¹. To enhance the energy density of the VACNF-V₂O₅ core-shell structures, the potential window is expanded to 4.0 – 1.0 V (vs Na/Na⁺) which achieved an initial insertion capacity of 277 mAh g⁻¹. The results demonstrate that amorphous V₂O₅ could serve as a cathode material in future SIBs.

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Li, Sheng. "Graphene-based Composites as Anode Materials for Rechargeable Batteries". Thesis, Griffith University, 2015. http://hdl.handle.net/10072/367790.

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With increasing demand for low cost and high performance energy resources, rechargeable batteries, such as lithium ion batteries (LIBs) and sodium ion batteries (SIBs), have been intensively studied in recent years. The performance of existing anode materials for both LIBs and SIBs need substantial improvements in terms of energy capacity, rate capability, stability, safety and manufacturing cost to modernize the battery applications in electric vehicles (EV) and energy-saving smart electric grids. Graphene is considered an effective additive in fabricating composites for anode materials since it possesses high electrical conductivity, large surface area and excellent mechanical properties. Therefore, this thesis attempts to synthesize a series of graphene-based composites as anode materials for LIBs and SIBs, to address the aforementioned concerns. To date, numerous methods have been developed for the fabrication of graphene composites; however, most of them are sophisticated, complex, not scalable and therefore expensive. A wet-mechanochemical (wet ball-milling) method that is simple, rapid, facile, economic and most importantly, can be up-scaled for mass production is proposed to address these issues.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
Griffith School of Environment
Science, Environment, Engineering and Technology
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30

Zhang, Yubai. "Electrochemical synthesis of 2D materials and their applications in energy storage". Thesis, Griffith University, 2021. http://hdl.handle.net/10072/410071.

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2D materials have inspired the intrigue of researchers and industries for its potential to improve the performance of existing materials in energy storage field. However, wide application of 2D material such as graphene and transition metal dichalcogenides in batteries is not implemented since the tremendous challenges and issues, the quality, quantity, and cost concerns impede its commercialization. Electrochemical approach performs as a controllable and scalable method for exfoliating, expanding, and functionalizing the pristine bulk materials on-demand. Sodium ion batteries, a promising candidate for lithium ion batteries, and aqueous zinc ion batteries, a safe energy storage system have received considerable attention in recent decades. The research herein focuses on the electrochemical exfoliation of graphite for its application in sodium ion battery anode, adopting the electrochemical graphene oxide (EGO) as functional agent combining with vanadium oxide for aqueous zinc ion battery cathode, and electrochemical production of molybdenum disulfide in a packed bed reactor. The PhD thesis generally is composed of three parts. In the first part, graphite is exfoliated and oxidized in a packed bed reactor. The effects of boron doping and oxidation on the graphene-based material were studied for high performance sodium ion battery anode respectively in Chapter 2 and Chapter 3. The electrochemical route from natural graphite to graphene oxide is investigated in terms of concentration of acid electrolyte (sulfuric acid). It was found that 12 M sulfuric acid reacted graphene oxide could deliver higher capacity of sodium ion battery than other concentrations. Boron doped graphene was synthesized by a twostep reaction, electrochemical fabrication of the tetraborate anions intercalated graphite oxide followed by reduction by annealing at 900 °C for 3 h under Ar gas. It was found that the boron doped graphene containing 0.21 at. % of boron was highly defective delivers a good capacity of 129.59 mAh g-1 at the current density of 100 mA g-1 and a long-term cyclic stability under current density of 500 mA g-1 retaining 100.20 mA g-1 after 800 cycles. The battery performance of boron doped graphene is better than that without boron doping. To further improve the sodium ion battery anode performance, mildly reduced graphite oxide with layered structure was synthesized by a simple electrochemical oxidation of expanded graphite followed by mildly heating reduction as reported in Chapter 3. The irrigated pipe in the expanded graphite packed bed assists with diffusion of electrolyte. A fast thermal reduction at 150 °C for 20 min on the electrochemical graphite oxide achieves a controlled deoxygenation and maintaining of the large interlayer gap of the product for high sodium storage capacity. The thermally processed electrochemically produced graphite oxide could deliver a high reversible capacity of 268 mAh g-1 at a current density of 100 mA g-1, and 163 mAh g-1 at a high current density of 500 mA g-1 and a good capacity retaining capability (in average 0.0198% loss per cycle) over 2000 cycles. In the second part, the EGO was integrated with vanadium oxide as cathode material for aqueous zinc ion battery. A simple spray dry method is applied to generate electrode materials, which is catering to industrial production. The aqueous mixture for spray drying is formed by quenching the molten V2O5. The products received after spray drying is vanadium oxide hydrate of amorphous structure. The zinc ion storage performance is investigated in terms of content of graphene oxide in the composite. The fabricated amorphous V2O5-EGO composite xerogel with 2D heterostructure possesses high zinc ion storage capability, high rate performance and stable cycling stability due to the functionality of graphene embedded in the composite material. In the third part, inspired by the common intercalation electrochemistry of graphite and transition metal dichalcogenide, exfoliation for 2D MoS2 from its bulk crystal powder is investigated by using the packed bed set up. Organic solvent is found to be a critical factor in the electrochemical activation and the mechanical exfoliation process. The MoS2 bulk crystal can be exfoliated to few-layer nanosheets with stable solution dispersibility. This finding further broadens the horizon of electrochemical production of transition metal dichalcogenides through a scalable approach of electrochemical reaction in packed bed. To sum up, this PhD thesis represents a huge step forward for EGO applications in sodium ion battery anode and aqueous zinc ion battery cathode. In addition, it develops a scalable production of vanadium oxide/graphene material by the spray dry method. The utility of the packed bed electrochemical reactor is extended to transition metal dichalcogenide MoS2. This work will be a valuable guidance for adoption of graphene, vanadium oxide, and MoS2 in the market of energy storage materials.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Environment and Science
Science, Environment, Engineering and Technology
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Bucher, Nicolas [Verfasser], Maria-Elisabeth [Akademischer Betreuer] Michel-Beyerle, Madhavi [Akademischer Betreuer] Srinivasan i Fritz Elmar [Akademischer Betreuer] Kühn. "On Improvements of Sodium Manganese Oxide Materials as Sodium-Ion Battery Cathode / Nicolas Bucher. Betreuer: Maria-Elisabeth Michel-Beyerle. Gutachter: Madhavi Srinivasan ; Maria-Elisabeth Michel-Beyerle ; Fritz Elmar Kühn". München : Universitätsbibliothek der TU München, 2016. http://d-nb.info/1096459000/34.

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Thanaweera, Achchige Dumindu P. "Design and characterisation of layered transition metal oxide cathode materials for Na-ion batteries". Thesis, Queensland University of Technology, 2022. https://eprints.qut.edu.au/228445/1/Dumindu_Thanaweera%20Achchige_Thesis.pdf.

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Owing to the scarcity of lithium, discovering alternatives for lithium in rechargeable batteries is a critical requirement. Sodium is an ideal candidate for this purpose. The absence of exceptional cathode materials in sodium-ion batteries is a bottleneck in realizing the above objective. This study focused on synthesizing novel transition metal oxide cathode materials for sodium-ion batteries and improving their electrochemical properties. The outcomes of this study emphasized the importance of novel material compositions as well as the role of smart cation substitution, anion redox reaction, electrochemical activation and the effect of the combination of strategies in achieving next-generation high-capacity cathodes.

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Hartung, Steffen Uwe [Verfasser], Maria-Elisabeth [Akademischer Betreuer] Michel-Beyerle, Madhavi [Akademischer Betreuer] Srinivasan i Fritz Elmar [Akademischer Betreuer] Kühn. "Vanadium-Based Materials as Electrode Materials in Sodium-Ion Batteries / Steffen Uwe Hartung. Betreuer: Maria-Elisabeth Michel-Beyerle. Gutachter: Madhavi Srinivasan ; Maria-Elisabeth Michel-Beyerle ; Fritz Elmar Kühn". München : Universitätsbibliothek der TU München, 2016. http://d-nb.info/1096458934/34.

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Xaba, Nqobile. "Development of Anode Materials Using Electrochemical Atomic Layer Deposition (E-ALD) for Energy Applications". University of the Western Cape, 2018. http://hdl.handle.net/11394/6390.

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Philosophiae Doctor - PhD (Chemistry)
Nanomaterials have been found to undeniably possess superior properties than bulk structures across many fields of study including natural science, medicine, materials science, electronics etc. The study of nano-sized structures has the ability to address the current world crisis in energy demand and climate change. The development of materials that have various applications will allow for quick and cost effective solutions. Nanomaterials of Sn and Bi are the core of the electronic industry for their use in micro packaging components. These nanomaterials are also used as electrocatalysts in fuel cells and carbon dioxide conversion, and as electrodes for rechargeable sodium ion batteries. There are various methods used to make these nanostructures including solid state methods, hydrothermal methods, sputtering, and vacuum deposition techniques. These methods lack the ability to control the structure of material at an atomic level to fine tune the properties of the final product. This study aims to use E-ALD technique to synthesis thin films of Sn and Bi for various energy applications, and reports the use of E-ALD in battery applications for the first time. Thin films were synthesised by developing a deposition sequence and optimising this deposition sequence by varying deposition parameters. These parameters include deposition potential, and concentration of precursor solution. The thin films were characterised using cyclic voltammetry, linear sweep voltammetry, chronoamperometry for electrochemical activity. These were also characterised using scanning electron microscope for morphology, x-ray diffraction for crystal phases, energy dispersive spectroscopy for elemental mapping, and focused ion beam scanning electron microscope for thickness. The elemental content was analysed using electron probe micro analysis and inductively coupled plasma mass spectrometry. The electrochemical impedance charge and discharge profile were used for electrochemical battery tests.

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Liang, Liying [Verfasser], Yong Akademischer Betreuer] Lei, Martin [Gutachter] [Hoffmann i Pu-Xian [Gutachter] Gao. "Rational design of antimony nanostructures toward high-performance anode materials for sodium-ion batteries / Liying Liang ; Gutachter: Martin Hoffmann, Pu-Xian Gao ; Betreuer: Yong Lei". Ilmenau : TU Ilmenau, 2017. http://d-nb.info/1178140784/34.

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Liang, Liying [Verfasser], Yong [Akademischer Betreuer] Lei, Martin [Gutachter] Hoffmann i Pu-Xian [Gutachter] Gao. "Rational design of antimony nanostructures toward high-performance anode materials for sodium-ion batteries / Liying Liang ; Gutachter: Martin Hoffmann, Pu-Xian Gao ; Betreuer: Yong Lei". Ilmenau : TU Ilmenau, 2017. http://nbn-resolving.de/urn:nbn:de:gbv:ilm1-2017000445.

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Mortemard, de boisse Benoit. "Etudes structurales et électrochimiques des matériaux NaxMn1-yFeyO2 et NaNiO2 en tant qu’électrode positive de batteries Na-ion". Thesis, Bordeaux, 2014. http://www.theses.fr/2014BORD0370/document.

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Ce travail présente les études électrochimiques et structurales menées sur deux systèmes : P2/O3-NaxMn1-yFeyO2 et O’3-NaxNiO2 utilisés en tant que matériaux d’électrode positive pour batteries Na-ion.Concernant le système P2/O3-NaxMn1-yFeyO2, l’étude par diffraction des rayons X menée in situ pendantla charge de batteries a montré de nombreuses transitions structurales. Que leur structure soit de type P2ou O3, les matériaux présentent une phase distordue pour les taux d’intercalation (x) les plus élevés etune phase très peu ordonnée pour les taux d’intercalation les moins élevés. Entre ces deux étatsd’intercalation, les phases de type P2 présentent moins de transitions que les phases de type O3. Celaentraine de meilleures propriétés électrochimiques pour les phases de type P2 (meilleure capacité endécharge, meilleure rétention de capacité…). Les spectroscopies d’absorption des rayons X et Mössbauerdu 57Fe ont montré que les couples redox Mn4+/Mn3+ et Fe4+/Fe3+ sont impliqués lors du cyclage, à bas ethaut potentiel, respectivement.Concernant O’3-NaNiO2, la diffraction des rayons-X menée in situ pendant la charge de batteriesO’3-NaNiO2//Na a montré de nombreuses transitions structurales O’3 ↔ P’3 résultant du glissement desfeuillets MO2. Ces transitions s’accompagnent de mises en ordre Na+ - lacunes dans le matériau. La tailledes grains a montré avoir un intérêt majeur puisqu’elle influe sur le nombre de phases présentessimultanément dans le matériau. Lorsque la batterie est déchargée, la phase limitante Na≈0.8NiO2 estobservée et empêche le retour à O’3-NaNiO2
This work concerns the electrochemical and structural studies carried out on two systems used aspositive electrode materials for Na-ion batteries: P2/O3-NaxMn1-yFeyO2 and O’3-NaxNiO2. Concerning theP2/O3-NaxMn1-yFeyO2 systems, in situ X-ray diffraction carried out during the charge of the batteriesshowed that both materials undergo several structural transitions. Both the P2 and O3 phases show adistorted phase for the higher intercalation rates (x) and a poorly ordered phase for the lower ones.Between these two states, P2-based materials exhibit less structural transitions than the O3-based ones.This is correlated to the better electrochemical properties the P2-based materials exhibit (better dischargecapacity, better capacity retention…). X-ray absorption and 57Fe Mössbauer spectroscopies showed thatthe Mn4+/Mn3+ and Fe4+/Fe3+ redox couples are active upon cycling, respectively at low and high voltage.Concerning O’3-NaNiO2, in situ X-ray diffraction carried out during the charge of O’3-NaNiO2//Nabatteries showed several structural transition between O’3 and P’3 structures, resulting from slab glidings.These transitions are accompanied by Na+ - vacancies ordering within the “NaO6” slabs. Upon discharge,the material does not come back to its initial state and, instead, the Na≈0.8NiO2 phase represents themaximum intercalated state. The occurrence of this limiting phase prevents O’3-NaNiO2 to be consideredas an interesting material for real Na-ion applications

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Mattsson, Agnes-Matilda, Towa Eriksson, Caroline Löwnertz i Marielle Holmbom. "Recycling of Prussian White". Thesis, Uppsala universitet, Institutionen för kemi - Ångström, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-445281.

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The aim of this project was to find a recycling route for Prussian white. During the experimental part, one recycling method was tested using sodium hydroxide and from this a method for re-synthesis of Prussian white was conducted as well as a method for re-crystallisation of sodium ferrocyanide. The method that proved most successful was the re-crystallisation of sodium ferrocyanide. Furthermore, the conditions needed to conduct a proper re-synthesis of Prussian white was not available during this research. Therefore, it was not possible to produce Prussian white of the right structure. The analysis was performed through XRD analysis and it was concluded that it is possible to re-crystallise sodium ferrocyanide from Prussian white.

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PIANTA, NICOLÒ. "Strategies for the optimization and characterization of materials for energy storage". Doctoral thesis, Università degli Studi di Milano-Bicocca, 2022. http://hdl.handle.net/10281/382288.

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Sin dalla sua invenzione, la batteria agli ioni di litio ha dominato il mercato dei sistemi di accumulo elettrochimico, grazie alle sue eccezionali proprietà in termini di energia e densità di potenza. Tuttavia, il fatto che questa tecnologia sia indissolubilmente legata a risorse rare e disomogenee distribuite, per lo più litio e cobalto, rende indispensabile avere delle alternative, se non sostituirla completamente almeno per diversificare il mercato e ridurre la dipendenza dai suddetti risorse rare. Due esempi di tali alternative sono la batteria agli ioni di Na e il condensatore elettrochimico a doppio strato. Questi dispositivi hanno la possibilità di competere con i LIB in alcune situazioni, ma entrambi potrebbero trarre grandi benefici da un aumento della loro densità di energia. Inoltre, il monitoraggio dell'evoluzione delle loro prestazioni dovrebbe essere considerato una priorità al fine di ottenere informazioni più approfondite su come migliorarle in modo da renderle paragonabili alle LIB. La ricerca di dottorato qui descritta si è concentrata su due obiettivi principali: proporre modi per migliorare la densità di energia dei sistemi di accumulo (NIB e EDLC) e suggerire una nuova tecnica per monitorare tali dispositivi operando: la spettroscopia di impedenza elettrochimica dinamica. La fabbricazione di elettrodi ad alto potenziale è un modo per migliorare le capacità di accumulo di energia di una batteria agli ioni di Na. In questa tesi è stato sintetizzato Na3V2(PO4)2F3, un materiale attivo in grado di immagazzinare ioni sodio ad un potenziale medio di 3,8 V vs Na+/Na. Questo materiale è stato utilizzato per fabbricare elettrodi massicci autoportanti (carico di massa attiva: 25 mg cm-2), che si è rivelato un metodo molto interessante per migliorare la densità di energia. L'NVPF è stato anche testato come un vero catodo in una cella a ioni di sodio completa in modo da dimostrarne l'alto potenziale e i relativi problemi. Per migliorare le densità energetiche degli EDLC, sono state preparate e studiate soluzioni altamente concentrate di acetato di potassio in acqua dalla loro caratterizzazione fisico-chimica ed elettrochimica all'uso di quelle più concentrate (elettrolita acqua-in-sale) in EDLC simmetrici a base di carbonio. Tali soluzioni si sono rivelate in grado di aumentare sia la capacità che la massima differenza di potenziale raggiungibile tra i due elettrodi, risultando in densità di energia maggiori rispetto agli elettroliti convenzionali (es. soluzione 6M KOH in acqua). Infine, la spettroscopia di impedenza elettrochimica dinamica è stata valutata come metodo per studiare NIB ed EDLC durante il ciclo. Due sistemi, un EDLC acquoso e un materiale di inserimento per NIBs, sono stati analizzati con dEIS: una tecnica in grado di monitorare i cambiamenti temporali nella spettroscopia di impedenza elettrochimica mentre un dispositivo subisce un processo ciclico. Questo approccio si è rivelato fattibile sia per le tecniche potenziodinamiche che per quelle galvanostatiche, consentendo di sondare l'impedenza dei singoli elettrodi anche in condizioni sperimentali simili a quelle con cui opera un dispositivo reale.
Ever since its invention, the Li-ion battery has dominated the market of electrochemical storage systems, thanks to its outstanding properties in terms of energy and power density. However, the fact that this technology is inextricably linked to non-homogenously distributed and rare resources, mostly lithium and cobalt, makes it essential to have alternatives, if not to completely replace it at least to diversify the market and reduce the dependence on the aforementioned rare resources. Two examples of such alternatives are the Na-ion battery and the electrochemical double-layer capacitor. These devices have the chance to compete with LIBs in some situations but both of them could greatly benefit from an increase in their energy density. Also, monitoring the evolution of their performances should be considered a priority in order to get deeper insights on how to improve them so to make them comparable to LIBs. The doctoral research here described was focused on two main objectives: proposing ways to improve the energy density of storage systems (NIBs and EDLCs) and suggesting a new technique to monitor such devices operando: the dynamic electrochemical impedance spectroscopy. Fabricating high potential electrodes is a way to improve the energy storage capabilities of a Na-ion battery. In this thesis, Na3V2(PO4)2F3, an active material able to store sodium-ions at a mean potential as high as 3.8 V vs Na+/Na, was synthesised. This material was used to fabricate self-standing massive electrodes (active mass loading: 25 mg cm-2), which proved to be a very interesting method to improve the energy density. NVPF was also tested as an actual cathode in a full sodium-ion cell so to prove its high potential and relative issues. To improve EDLCs energy densities, highly concentrated solutions of potassium acetate in water were prepared and studied from their physicochemical and electrochemical characterization to the use of the highest concentrated ones (water-in-salt electrolyte) in symmetric carbon-based EDLCs. Such solutions proved to be able to increase both the capacitance and the maximum reachable potential difference between the two electrodes, resulting in higher energy densities compared to conventional electrolytes (e.g. 6M KOH solution in water). Finally, dynamic electrochemical impedance spectroscopy was evaluated as a method to study NIBs and EDLCs while cycling. Two systems, an aqueous EDLC and an insertion material for NIBs, were analysed with dEIS: a technique able to monitor the temporal changes in the electrochemical impedance spectroscopy while a device undergoes a cycling process. This approach proved to be doable for both potentiodynamic and galvanostatic techniques, allowing to probe the impedance of the single electrodes even in experimental conditions similar to those with which a real device operates.

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Gao, Suning [Verfasser], Rudolf [Gutachter] Holze, Rudolf [Akademischer Betreuer] Holze i Qunting [Gutachter] Qu. "Layered transition metal sulfide- based negative electrode materials for lithium and sodium ion batteries and their mechanistic studies / Suning Gao ; Gutachter: Rudolf Holze, Qunting Qu ; Betreuer: Rudolf Holze". Chemnitz : Technische Universität Chemnitz, 2020. http://d-nb.info/1219910309/34.

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Khan, Anastassiya. "Synthesis and characterization of defective PBAs electrode material". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/21015/.

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Sodium manganese hexacyanoferrate (NaMnHCF) and its derivatives have been synthesized by simple co-precipitation method with addition of the citric and ascorbic acids respectively. The correspondent crystal structure, water content, chemical formula and a deep structural investigation of prepared samples have been performed by means of the combination of the laboratory and synchrotron techniques (PXRD, FT-IR, TGA, MP-AES and XAS). Electrochemical tests have been done using three-electrode system in sodium nitrate solution at different concentration. From cyclic voltammetry curves, Fe3+/2+ redox peak has been observed, whereas Mn3+/2+ peak was not always evident. Structural stability of the cycled samples has then been tested using 2D XRF imaging and Transmission X-ray microscopy (TXM) techniques. The intercalation of NaMnHCF after 20 cycles has been found by micro-XANES analysis of the highlighted spots which have been found in the XRF images. TXM has also confirmed the appearance of the intercalated particles after 50 cycles comparing the spectra between charged and discharged materials at three different edges (Mn, Fe and N). However, by comparison with lithium samples, it seems obvious that sodium samples are more homogeneous and intercalation is at the very beginning indicating the relative structural stability of sodium manganese hexacyanoferrate electrode material.

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Bhatti, Asif Iqbal. "Calculs ab-initio et simulations atomistiques des propriétés thermodynamiques et cinétiques de complexes de métaux de transition utilisés comme batteries". Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAI092/document.

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Ce travail théorique vise à étudier, via les méthodes Premiers Principes, les propriétés des complexes de métaux de transitions, left[Mleft(dmbpyright)_{3}right]^{n+}nCi^{-} pour un usage en batterie. Pour cette étude ab-initio, les composés mono et bi-nucléaires ont été retenus. La pertinance de notre modélisation a été validée sur les composés mononucléaires. Nous nous sommes interessé au complexes de Fe, Ru et Cu pour lesquels une validation expérimentale était possible. Notre étude a principalement consisté à faire varier les degrés de liberté que nous possédons pour optimiser le voltage et la cinétique de chargement des batteries. Pour cela, nous avons fait varier le TM = Fe, Ru, et Cu, la nature des contre-ions Ci^{-}=PF_{6}^{-}, TFSI^{-} et ClO_{4}^{-} en interaction avec le polymère lors du processus de charge, ainsi que la longeur de la chaîne alkyl qui sépare les deux monomers dans le cas des composés binucléaires. Le composé à base de Fe avec une chaîne -left(CH_{2}right)_{n=6}- a été retenu comme le meilleur candidat pour une application batterie. Le composé à base Ru montre un comportement proche de celui du Fe, quant-au complexe de Cu, il présente des changements de géométrie locale sous chargement trop importants, le rendant peu apte à conduire à une cinétique efficace. Cette étude nous a permis de déterminer que l'approximation PBE était le meilleur choix possible pour modéliser nos complexes dans les conditions de fonctionnement en batterie (dans le champ créé par les contre-ions) et que l'approximation PBE0, généralement utilisée dans la littérature, ne pouvait rendre compte de la physico-chimie de nos composés dans de telles conditions.De surcroît, nous avons dévelopé pour le complexe de Fe, un potentiel atomistique de type “Champ de forces” de manière à pouvoir aborder les aspects dynamiques impliquant de plus grandes tailles de boîte de simulation. Ici, nous modélisons une structure 3D, totalement réticulée à partir de nos monomères à base de Fe. Nous nous sommes servi de la base de donnés DFT que nous avions généré (énergies, géométries, état de spin et fréquences vibrationnelles calculées) pour ajuster les paramètres entrant dans l'écriture du modèle. La construction de la géométrie initiale du polymère 3D a nécessité l'écriture d'un code de calcul visant à produire un arrangement complétement réticulé et à assigner les charges effectives issues des calculs DFT. Ce modèle nous a permis de déterminer les coefficients de diffusion des contre-ions pour les états totalement chargé et non-chargé. Un calcul plus ambitieux vise à déterminer les chemins de diffusion des contre-ions lors d'un processus de chargement en considérant un seul centre de degré d'oxydation 3+ au centre du polymère 3D, pour lequel les centres actifs possèdent un degré d'oxidation 2+. Les contre-ions assurent la neutralité globale.Keyword: Polymer, Electrochemistry, Li-ion Battery, DFT, Force Field development, 3D structure, Atomistic modeling
Abstract Standard redox potentials for mono and bi-nuclear transition metal (TM) complexes left[Mleft(dmbpyright)_{3}right]^{n+}nCi^{-}, have been investigated using First Principles Calculation. Three metal centers are investigated: Fe, Ru, and Cu. Our modeling is validated on mono-nuclear compounds. This approach consists in determining the best small polymer (bi-nuclear) made out of these monomers for a battery application. For that, we varied the three available degrees of freedom i.e., the nature of the central TM atom (Fe, Ru, and Cu), counter-ions Ci=PF_{6}^{-}, TFSI^{-} and ClO_{4}^{-} in interaction with the polymer, and the alkyl chain -left(CH_{2}right)_{n}- of length n that connects both mono-nuclear in the bi-nuclear compound. The Iron compound with -left(CH_{2}right)_{n=6}- is found to be the best candidate. The left[Culeft(dmbpyright)_{2}right]^{n+}nCi^{-} complex shows too much structure deformation upon loading, making it less reliable for cathode material. Moreover, we studied two XC functional, PBE and PBE0 and found, for three complexes PBE approximation retains the ligand field picture whereas PBE0 functional induces an exaggerated and unexpected band dispersion by dissolving the ligand field picture expected for the octahedral environment of the TM in the studied complexes. These findings validate that hybrid functional for which it was designed to localize and cancel self-interaction error does not work for all system. More particularly, the PBE0 approximation fails to model the three complexes (Fe, Ru, and Cu) in functional conditions (in the field made by the counter-ions).Abstract Further, we have developed an atomistic potential relying on the Force Field scheme for the Iron complex in order to study the dynamical properties of this compound at larger simulation scale (3D reticulated polymerization made of our Fe complex monomers). We made an intensive use of our DFT data (energies, geometries, spin-state configurations and calculated vibrational properties) to develop the required parameters entering the model. Moreover, computational techniques (written python language) were developed specifically to create a 3D structure of transition metal complexes satisfying the condition to be fully reticulated. Bounding conditions had to be designed and a procedure aiming at fixing reliable and physical effective charges on each atom of the simulation cell (compatible with DFT results) were developed. Our first simulations have been attached to calculate the diffusion coefficients of the counter-ions in both the fully loaded and unloaded states. A more ambitious and realistic calculation aims at investigating the paths of the counter-ions when one single center starts to be loaded in an unloaded environment.Abstract Keyword: Polymer, Electrochemistry, Li-ion Battery, DFT, Force Field development, 3D structure, Atomistic modeling

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Nguyen, Long Hoang Bao. "Cristallochimie d’oxyphosphates fluorés de vanadium : De l’étude de leur structure à leurs performances en batteries Na-ion". Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0356.

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Les batteries Na-ion se développent comme une nouvelle alternative aux batteries Li-ion. Parmi le grand nombre de matériaux déjà étudiés à l’électrode positive, Na3V2(PO4)2F3 et Na3(VO)2(PO4)2F sont les plus performants grâce à des capacités théoriques élevées, des potentiels d’extraction des ions Na+ élevés, et la stabilité de la structure lors de cyclages longues durées. De plus, la structure et les propriétés électrochimiques des matériaux Na3V2(PO4)2F3 et Na3(VO)2(PO4)2F peuvent être modulées par un effet de substitution cationique ou anionique. Ce travail de thèse a pour but d’explorer la cristallochimie de nouveaux matériaux dérivés de Na3V2(PO4)2F3 et Na3(VO)2(PO4)2F. Dans un premier temps, différentes modes de synthèse (voies tout solide, céramique assistée par sol-gel, et broyage mécanique) sont explorées pour réaliser des substitutions cationiques et anioniques. La structure tridimensionnelle à longue distance de ces matériaux est déterminée par diffraction des rayons X synchrotron, tandis que les environnements locaux sont ensuite décrits finement en combinant des techniques de spectroscopies (résonance magnétique nucléaire à l’état solide, absorption des rayons X, et infra-rouge) dont l’interprétation est appuyée par des calculs théoriques. Les diagrammes de phases et les processus d’oxydoréduction impliqués lors des réactions de dés-intercalation et de ré-intercalation des ions Na+ de la structure hôte sont étudiés pour chacune des compositions, operando (cad. lors du fonctionnement de la batterie) en diffraction et absorption des rayons X synchrotron. Une compréhension des mécanismes structuraux et redox impliqués au cours du cyclage permet d’identifier les limitations de ces phases et de nous guider pour proposer des nouveaux matériaux dérivés présentant de meilleures performances
Na-ion batteries are currently developed as a future alternative to the conventional Li-ion batteries. Among all the polyanion materials studied as positive electrodes for Na-ion batteries, Na3V2(PO4)2F3 and Na3(VO)2(PO4)2F are the two promising compositions thanks to their high theoretical capacity, high Na+-extraction voltage, and especially the high stability of their structural framework upon long-term cycling. Furthermore, the crystal structure and the electrochemical properties of these materials can be greatly modulated through an effect of cationic or anionic substitution. This PhD work aims at exploring the diversity in crystal chemistry of Na3V2(PO4)2F3, Na3(VO)2(PO4)2F and their derivatives obtained through different synthesis methods. The three-dimensional long range crystal structure of these phases is determined by the use of high resolution synchrotron X-ray powder diffraction whereas their local atomic and electronic structures are investigated through a combination of solid-state nuclear magnetic resonance supported by first-principles theoretical calculations, synchrotron X-ray absorption spectroscopy and infrared spectroscopy. Thereafter, the phase diagram and the redox processes involved in the Na+ de-intercalation and intercalation are established thanks to operando synchrotron X-ray diffraction and absorption. An in-depth understanding on the crystal structure as well as the involved redox couples for each composition helps us to determine the limitations of these vanadium fluorinated oxy-phosphates and sheds light to the development of new materials with better performance based on their structure

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44

Sharma, Vaishali M. "Structural Characterization Of Complex Oxides And Sulfates Towards the Design of Photocatalytic And Sodium Ion Conducting Materials". Thesis, 2017. https://etd.iisc.ac.in/handle/2005/4207.

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The thesis entitled "Structural Characterization of Complex Oxides and Sulfates Towards the Design of Photocatalytic and Sodium Ion Conducting Materials" consists of _ve chapters. Chapter 1 gives a brief introductory note which outlines the various synthesis procedures, characterization techniques and a description of properties like photocatalysis and ionic conductivity. Chapter 2 discusses the solution combustion synthesis of Bi2Zr2O7 using urea, tartaric Acid and glycine as fuels. Only the samples prepared using urea and tartaric acid result in pure compounds and are further characterized by X-ray di_raction studies depicting a disordered uorite type structures. Careful Rietveld re_nements bring out subtle structural di_erences in these two samples as well, a feature which is demonstrated for the _rst time among samples prepared from two di_erent fuels. Di_erence Fourier maps con_rms the structures, and the catalytic behaviour is shown to correlate to these subtle changes in oxygen occupancy. The band gap determined from UV-Vis spectroscopic results conform to the structural di_erences of the compound. Photocatalytic degradation of cation dyes suggest that the compound prepared using urea shows better photocatalytic activity and is comparable to the commercial Degussa P-25. Chapter 3 describes the e_ect of Bi doping on photocatalytic activity of CeO2 (band gap is in the UV range) is evaluated with BixCe1-xO2􀀀_ (x = 0.2, 0.4, 0.6) using solution combustion method using glycine as fuel. These compounds have a band gap in the visible range and the structures are established by Rietveld re_nements clearly establishing that the oxygen vacancies increase with increasing bismuth substitution. Featureless di_erence Fourier maps con_rm the structures and photodegradation experiments on a cationic and an anionic dye clearly establishing that the photocatalytic activity increases with increase in bismuth content leading to increased oxygen vacancies. Chapter 4 describes synthesis, crystal structure, phase transition and ionic conductivity in a family of vantho_te mineral Na6Mn(SO4)4. Single crystal of Na6Mn(SO4)4 are grown from aqueous solution by slow evaporation method at 80°C, crystal grown are analyzed by single crystal X-ray di_raction which depict monoclinic system with space group P21/c at room temperature. Ionic conductivity measurements are carried out by using impedance spectroscopy, and conductivity value is found to be 2.01x10􀀀5 Scm􀀀1 at 490°C and 7.4x10􀀀3 Scm􀀀1 at 505°C. Two order magnitude change in conductivity value on a temperature window of 15°C con_rms a _rst order nature of phase transition. Further, conductivity of the mineral reached of 3.9x10􀀀2 Scm􀀀1 at 600°C which establishes the superionic nature of the mineral.In addition, the nature of phase transition was examined by using thermal analysis such asDSC, DTA and variable temperature powder X-ray di_raction technique. The PXRD after the phase transition at 550°C was also indexed, pro_le _tted with orthorhombic space group. Chapter 5 presents the crystal growth and in situ structural studies of di and tetra hydrate of vantho_te mineral Na6M(SO4)4 (M = Ni and Co). As discussed in Chapter 4, these crystals are grown in aqueous solution by slow evaporation method at 80°C in an oven. Interestingly, di and tetra hydrate of Na6M(SO4)4 (M = Ni and Co) are grow concomitantly. Single crystal X-ray di_raction measurements reveal the structure to be triclinic with space group P_1. Further di-hydrates of Na6M(SO4)4 (M = Ni and Co) are isostructural, and the tetrahydrates also follow the same trend. Thermal Gravimetric analyses and in situ powder di_raction studies were carried out to characterize the step-wise dehydration process in these materials.

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45

Versek, Craig Wm. "Charge transport studies of proton and ion conducting materials". 2013. https://scholarworks.umass.edu/dissertations/AAI3589209.

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The development of a high-throughput impedance spectroscopy instrumentation platform for conductivity characterization of ion transport materials is outlined. Collaborative studies using this system are summarized. Charge conduction mechanisms and conductivity data for small molecule proton conducting liquids, pyrazole, imidazole, 1,2,3-triazole, 1,2,4-triazole, and select mixtures of these compounds are documented. Furthermore, proton diffusivity measurements using a Pulse Field Gradient Nuclear Magnetic Resonance (PFG NMR) technique for imidazole and 1,2,3-triazole binary mixtures are compared. Studies of azole functionalized discotic and linear mesogens with conductivity, structural, and thermal characterizations are detailed.

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46

Versek, Craig William. "Charge Transport Studies of Proton and Ion Conducting Materials". 2013. https://scholarworks.umass.edu/open_access_dissertations/770.

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The development of a high-throughput impedance spectroscopy instrumentation platform for conductivity characterization of ion transport materials is outlined. Collaborative studies using this system are summarized. Charge conduction mechanisms and conductivity data for small molecule proton conducting liquids, pyrazole, imidazole, 1,2,3-triazole, 1,2,4-triazole, and select mixtures of these compounds are documented. Furthermore, proton diffusivity measurements using a Pulse Field Gradient Nuclear Magnetic Resonance (PFG NMR) technique for imidazole and 1,2,3-triazole binary mixtures are compared. Studies of azole functionalized discotic and linear mesogens with conductivity, structural, and thermal characterizations are detailed.

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47

"Mixed Polyanion and Clathrate Materials as Novel Materials for Lithium-ion and Sodium-ion Batteries". Doctoral diss., 2017. http://hdl.handle.net/2286/R.I.44215.

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abstract: This work describes the investigation of novel cathode and anode materials. Specifically, several mixed polyanion compounds were evaluated as cathodes for Li and Na-ion batteries. Clathrate compounds composed of silicon or germanium arranged in cage-like structures were studied as anodes for Li-ion batteries. Nanostructured Cu4(OH)6SO4 (brochantite) platelets were synthesized using polymer-assisted titration and microwave-assisted hydrothermal methods. These nanostructures exhibited a capacity of 474 mAh/g corresponding to the full utilization of the copper redox in an conversion reaction. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) studies were preformed to understand the mechanism and structural changes. A microwave hydrothermal synthesis was developed to prepare a series compounds based on jarosite, AM3(SO4)2(OH)6 (A = K, Na; M = Fe, V). Both the morphology and electrochemical properties showed a compositional dependence. At potentials >1.5 V vs. Li/Li+, an insertion-type reaction was observed in Na,Fe-jarosite but not in K,Fe-jarosite. Reversible insertion-type reactions were observed in both vanadium jarosites between 1 – 4 V with capacities around 40 - 60 mAh/g. Below 1 V vs. Li/Li+, all four jarosite compounds underwent conversion reactions with capacities ~500 mAh/g for the Fe-jarosites. The electrochemical properties of hydrogen titanium phosphate sulfate, H0.4Ti2(PO4)2.4(SO4)0.6 (HTPS), a new mixed polyanion material with NASICON structure was reported. A capacity of 148 mAh/g corresponding to2 Li+ insertion per formula unit was observed. XRD and XPS were used to characterize the HTPS before and after cycling and to identify the lithium sites. Evaluation of the HTPS in Na-ion cell was also performed, and a discharge capacity of 93 mAh/g was observed. A systematic investigation of the role of the processing steps, such as ball-milling and acid/base etching, on the electrochemical properties of a silicon clathrate compound with nominal composition of Ba8Al16Si30 was performed. According to the transmission electron microscope (TEM), XPS, and electrochemical analysis, very few Li atoms can be electrochemically inserted, but the introduction of disorder through ball-milling resulted in higher capacity, while the oxidation layer made by the acid/base treatment prevented the reation. The electrochemical property of germanium clathrate was also investigated, unlike the silicon clathrate, the germanium one underwent a conversion reaction.
Dissertation/Thesis
Doctoral Dissertation Chemistry 2017

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48

Lin, Yong-Mao. "Nanostructured anode materials for Li-ion and Na-ion batteries". 2013. http://hdl.handle.net/2152/21580.

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The demand for electrical energy storage has increased tremendously in recent years, especially in the applications of portable electronic devices, transportation and renewable energy. The performances of lithium-ion and sodium-ion batteries depend on their electrode materials. In commercial Li-ion batteries with graphite anodes the intercalation potential of lithium in graphite is close to the reversible Li/Li⁺ half-cell potential. The proximity of the potentials can result in unintended electroplating of metallic instead of intercalation of lithium in the graphite anode and frequently leads to internal shorting and overheating, which constitute unacceptable hazards, especially when the batteries are large, as they are in cars and airplanes. Moreover, graphite cannot be readily used as the anode material of Na-ion batteries, because electroplating of metallic sodium on graphite is kinetically favored over sodium intercalation in graphite. This dissertation examines safer Li-ion and Na-ion battery anode materials.
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Zhang, Fan. "SnSe2 Two Dimensional Anodes for Advanced Sodium Ion Batteries". Thesis, 2017. http://hdl.handle.net/10754/625032.

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Sodium-ion batteries (SIBs) are considered as a promising alternative to lithium-ion batteries (LIBs) for large-scale renewable energy storage units due to the abundance of sodium resource and its low cost. However, the development of anode materials for SIBs to date has been mainly limited to some traditional anodes for LIBs, such as carbonaceous materials. SnSe2 is a member of two dimensional layered transition metal dichalcogenide (TMD) family, which has been predicted to have high theoretical capacity as anode material for sodium ion batteries (756 mAh g-1), thanks to its layered crystal structure. Yet, there have been no studies on using SnSe2 as Na ion battery anode. In this thesis, we developed a simple synthesis method to prepare pure SnSe2 nanosheets, employing N2 saturated NaHSe solution as a new selenium source. The SnSe2 2D sheets achieve theoretical capacity during the first cycle, and a stable and reversible specific capacity of 515 mAh g-1 at 0.1 A g-1 after 100 cycles, with excellent rate performance. Among all of the reported transition metal selenides, our SnSe2 sample has the highest reversible capacity and the best rate performances. A combination of ex-situ high resolution transmission electron microscopy (HRTEM) and X-ray diffraction was used to study the mechanism of sodiation and desodiation process in this SnSe2, and to understand the reason for the excellent results that we have obtained. The analysis indicate that a combination of conversion and alloying reactions take place with SnSe2 anodes during battery operation, which helps to explain the high capacity of SnSe2 anodes for SIBs compared to other binary selenides. Density functional theory was used to elucidate the volume changes taking place in this important 2D material.

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Luo, Xu-Feng, i 羅旭峰. "Graphene and carbon-based materials as anodes for sodium-ion batteries". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/34108554903885182523.

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碩士
國立中央大學
材料科學與工程研究所
102
Holey reduced graphene oxide (RGO) is prepared by a Staudenmaier method, followed by a thermal reduction process. Amounts of functional groups on RGO can be controlled by the reduction temperature. In this study, electrochemical properties of the RGO electrodes are tested in an ethylene carbonate/diethyl carbonate mixed electrolyte containing 1 M NaClO4. The RGO reduced at 1100 oC (HGNS-1100) with a low content of functional groups shows a reversible capacity of 147 mAh/g (at 0.03 A/g). However, the RGO reduced at 300 oC (HGNS-300; with a higher surface functional group amount) shows a clearly higher capacity of 213 mAh/g at the same condition. With increasing the charge-discharge to 5, 10 and 20 A/g, a capacity of as high as 104, 83 and 58 mAh/g can be obtained, indicating an excellent rate capability. The functional groups may increase d-spacing and provide reaction sites for sodium ion storage, enhancing charge/discharge capacity. In addition, holey morphology can shorten the path of Na-ion diffusion, optimizing the rate capability. HGNS-300 shows the higher rate capability 44.6 %. GNS-300 (without holey morphology) only has 38.6 % at the same condition. It is also found that the RGO-300 electrode exhibits a capacity retention ratio of approximately 70 % after 100 cycles. In order to study the reason of excellent electrochemical performance of HGNS-300, the methods of ex-situ XRD and ex-situ XPS are used to analyze the structure and surface properties change during charge/discharge process. It confirms that Na-ion will insert to carbon layers in the lower sodiation voltage (0.4~0.3 V). In the higher sodiation voltage 2~0.4 V, Na-ion will storage at surface active site from surface functional group. The reaction mechanism is “>C=O + Na+ + e- ↔ >C-O-Na”. Due to the two kinds of mechanism that mention in above paragraph, HGNS-300 can own both high capacity and excellent rate capability.

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