Dissertationen: „Lithium/sodium metal batteries“

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David, Lamuel Abraham. „Van der Waals sheets for rechargeable metal-ion batteries“. Diss., Kansas State University, 2015. http://hdl.handle.net/2097/32796.

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Doctor of Philosophy
Department of Mechanical and Nuclear Engineering
Gurpreet Singh
The inevitable depletion of fossil fuels and related environmental issues has led to exploration of alternative energy sources and storage technologies. Among various energy storage technologies, rechargeable metal-ion batteries (MIB) are at the forefront. One dominant factor affecting the performance of MIB is the choice of electrode material. This thesis reports synthesis of paper like electrodes composed for three representative layered materials (van der Waals sheets) namely reduced graphene oxide (rGO), molybdenum disulfide (MoS₂) and hexagonal boron nitride (BN) and their use as a flexible negative electrode for Li and Na-ion batteries. Additionally, layered or sandwiched structures of vdW sheets with precursor-derived ceramics (PDCs) were explored as high C-rate electrode materials. Electrochemical performance of rGO paper electrodes depended upon its reduction temperature, with maximum Li charge capacity of 325 mAh.g⁻¹ observed for specimen annealed at 900°C. However, a sharp decline in Na charge capacity was noted for rGO annealed above 500 °C. More importantly, annealing of GO in NH₃ at 500 °C showed negligible cyclability for Na-ions while there was improvement in electrode's Li-ion cycling performance. This is due to increased level of ordering in graphene sheets and decreased interlayer spacing with increasing annealing temperatures in Ar or reduction at moderate temperatures in NH₃. Further enhancement in rGO electrodes was achieved by interfacing exfoliated MoS₂ with rGO in 8:2 wt. ratios. Such papers showed good Na cycling ability with charge capacity of approx. 225.mAh.g⁻¹ and coulombic efficiency reaching 99%. Composite paper electrode of rGO and silicon oxycarbide SiOC (a type of PDC) was tested as high power-high energy anode material. Owing to this unique structure, the SiOC/rGO composite electrode exhibited stable Li-ion charge capacity of 543.mAh.g⁻¹ at 2400 mA.g⁻¹ with nearly 100% average cycling efficiency. Further, mechanical characterization of composite papers revealed difference in fracture mechanism between rGO and 60SiOC composite freestanding paper. This work demonstrates the first high power density silicon based PDC/rGO composite with high cyclic stability. Composite paper electrodes of exfoliated MoS₂ sheets and silicon carbonitride (another type of PDC material) were prepared by chemical interfacing of MoS₂ with polysilazane followed by pyrolysis . Microscopic and spectroscopic techniques confirmed ceramization of polymer to ceramic phase on surfaces on MoS₂. The electrode showed classical three-phase behavior characteristics of a conversion reaction. Excellent C-rate performance and Li capacity of 530 mAh.g⁻¹ which is approximately 3 times higher than bulk MoS₂ was observed. Composite papers of BN sheets with SiCN (SiCN/BN) showed improved electrical conductivity, high-temperature oxidation resistance (at 1000 °C), and high electrochemical activity (~517 mAh g⁻¹ at 100 mA g⁻¹) toward Li-ions generally not observed in SiCN or B-doped SiCN. Chemical characterization of the composite suggests increased free-carbon content in the SiCN phase, which may have exceeded the percolation limit, leading to the improved conductivity and Li-reversible capacity. The novel approach to synthesis of van der Waals sheets and its PDC composites along with battery cyclic performance testing offers a starting point to further explore the cyclic performance of other van der Waals sheets functionalized with various other PDC chemistries.

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Kautz, Jr David Joseph. „Investigation of Alkali Metal-Host Interactions and Electrode-Electrolyte Interfacial Chemistries for Lean Lithium and Sodium Metal Batteries“. Diss., Virginia Tech, 2021. http://hdl.handle.net/10919/103946.

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The development and commercialization of alkali ion secondary batteries has played a critical role in the development of personal electronics and electric vehicles. The recent increase in demand for electric vehicles has pushed for lighter batteries with a higher energy density to reduce the weight of the vehicle while with an emphasis on improving the mile range. A resurgence has occurred in lithium, and sodium, metal anode research due to their high theoretical capacities, low densities, and low redox potentials. However, Li and Na metal anodes suffer from major safety issues and long-term cycling stability. This dissertation focuses on the investigation of the interfacial chemistries between alkali metal-carbon host interactions and the electrode-electrolyte interactions of the cathode and anode with boron-based electrolytes to establish design rules for "lean" alkali metal composite anodes and improve long-term stability to enable alkali metal batteries for practical electrochemical applications. Chapter 2 of this thesis focuses on the design and preliminary investigation of "lean" lithium-carbon nanofiber (<5 mAh cm-2) composite anodes in full cell testing using a LiNi0.6Mn0.2Co0.2O2 (NMC 622) cathode. We used the electrodeposition method to synthesize the Li-CNF composite anodes with a range of electrodeposition capacities and current densities and electrolyte formulations. Increasing the electrodeposition capacity improved the cycle life with 3 mAh cm-2 areal capacity and 2% vinylene carbonate (VC) electrolyte additive gave the best cycle life before reaching a state of "rapid cell failure". Increasing the electrodeposition rate reduced cycling stability and had a faster fade in capacity. The electrodeposition of lithium metal into a 2D graphite anode significantly improved cycle life, implying the increased crystallinity of the carbon substrate promotes improved anode stability and cycling capabilities. As the increased crystallinity of the carbon anode was shown to improve the "lean" composite anode's performance, Chapter 3 focuses on utilizing a CNF electrode designed with a higher degree of graphitization and probing the interacting mechanism of Li and Na with the CNF host. Characterization of the CNF properties found the material to be more reminiscent of hard carbon materials. Electrochemical analysis showed better long-term performance for Na-CNF symmetric cells. Kinetic analysis, using cyclic voltammetry (CV), revealed that Na ions successfully (de)intercalated within the CNF crystalline interlayers, while Li ions were limited to surface adsorption. A change in mechanism was quickly observed in the Na-CNF symmetric cycling from metal stripping/plating to ion intercalation/deintercalation, enabling the superior cycling stability of the composite anode. Improving the Na metal stability is necessary for enabling Na-CNF improved long-term performance. Sodium batteries have begun to garner more attention for grid storage applications due to their overall lower cost and less volumetric constraint required. However, sodium cathodes have poor electrode-electrolyte stability, leading to nanocracks in the cathode particles and transition metal dissolution. Chapter 4 focuses on electrolyte engineering with the boron salts sodium difluoro(oxolato)borate (NaDFOB) and sodium tetrafluoroborate (NaBF4) mixed together with sodium hexafluorophosphate (NaPF6) to improve the electrode-electrolyte compatibility and cathode particle stability. The electrolytes containing NaDFOB showed improved electrochemical stability at various temperatures, the formation of a more robust electrode-electrolyte interphase, and suppression in transition metal (TM) reduction and dissolution of the cathode particles measured after cycling. In Chapter 5, we focus on the electrochemical properties and the anode-electrolyte interfacial chemistry properties of the sodium borate salt electrolytes. Similar to Chapter 4, the NaDFOB containing electrolytes have improved electrochemical performance and stability. Following the same electrodeposition parameters as Chapter 2, we find the NaDFOB electrolytes improves the stability of electrodeposited Na metal and the "lean" composite anode's cyclability. This study suggests the great potential for the NaDFOB electrolytes for Na ion battery applications.
Doctor of Philosophy
The ever-increasing demand for high energy storage in personal electronics, electric vehicles, and grid energy storage has driven for research to safely enable alkali metal (Li and Na) anodes for practical energy storage applications. Key research efforts have focused on developing alkali metal composite anodes, as well as improving the electrode-electrolyte interfacial chemistries. A fundamental understanding of the electrode interactions with the electrolyte or host materials is necessary to progress towards safer batteries and better battery material design for long-term applications. Improving the interfacial interactions between the host-guest or electrode-electrolyte interfaces allows for more efficient charge transfer processes to occur, reduces interfacial resistance, and improves overall stability within the battery. As a result, there is great potential in understanding the host-guest and electrode-electrolyte interactions for the design of longer-lasting and safer batteries. This dissertation focuses on probing the interfacial chemistries of the battery materials to enable "lean" alkali metal composite anodes and improve electrode stability through electrolyte interactions. The anode-host interactions are first explored through preliminary design development for "lean" alkali composite anodes using carbon nanofiber (CNF) electrodes. The effect on increasing the crystallinity of the CNF host on the Li- and Na-CNF interactions for enhanced electrochemical performance and stability is then investigated. In an effort to improve the capabilities of Na batteries, the electrode-electrolyte interactions of the cathode- and anode-electrolyte interfacial chemistries using sodium borate salts are probed using electrochemical and X-ray analysis. Overall, this dissertation explores how the interfacial interactions affect, and improve, battery performance and stability. This work provides insights for understanding alkali metal-host and electrode-electrolyte properties and guidance for potential future research of the stabilization for Li- and Na-metal batteries.

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Hwang, Jinkwang. „A Study on Enhanced Electrode Performance of Li and Na Secondary Batteries by Ionic Liquid Electrolytes“. Kyoto University, 2019. http://hdl.handle.net/2433/245327.

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4

Liu, Chenjuan. „Exploration of Non-Aqueous Metal-O2 Batteries via In Operando X-ray Diffraction“. Doctoral thesis, Uppsala universitet, Strukturkemi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-330889.

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Non-aqueous metal-air (Li-O2 and Na-O2) batteries have been emerging as one of the most promising high-energy storage systems to meet the requirements for demanding applications due to their high theoretical specific energy. In the present thesis work, advanced characterization techniques are demonstrated for the exploration of metal-O2 batteries. Prominently, the electrochemical reactions occurring within the Li-O2 and Na-O2 batteries upon cycling are studied by in operando powder X-ray diffraction (XRD). In the first part, a new in operando cell with a combined form of coin cell and pouch cell is designed. In operando synchrotron radiation powder X-ray diffraction (SR-PXD) is applied to investigate the evolution of Li2O2 inside the Li-O2 cells with carbon and Ru-TiC cathodes. By quantitatively tracking the Li2O2 evolution, a two-step process during growth and oxidation is observed. This newly developed analysis technique is further applied to the Na-O2 battery system. The formation of NaO2 and the influence of the electrolyte salt are followed quantitatively by in operando SR-PXD. The results indicate that the discharge capacity of Na-O2 cells containing a weak solvating ether solvent depends heavily on the choice of the conducting salt anion, which also has impact on the growth of NaO2 particles. In addition, the stability of the discharge product in Na-O2 cells is studied. Using both ex situ and in operando XRD, the influence of sodium anode, solvent, salt and oxygen on the stability of NaO2 are quantitatively identified. These findings bring new insights into the understanding of conflicting observations of different discharge products in previous studies. In the last part, a binder-free graphene based cathode concept is developed for Li-O2 cells. The formation of discharge products and their decomposition upon charge, as well as different morphologies of the discharge products on the electrode, are demonstrated. Moreover, considering the instability of carbon based cathode materials, a new type of titanium carbide on carbon cloth cathode is designed and fabricated. With a surface modification by loading Ru nanoparticles, the titanium carbide shows enhanced oxygen reduction/evolution activity and stability. Compared with the carbon based cathode materials, titanium carbide demonstrated a higher discharge and charge efficiency.

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Wang, Luyuan Paul. „Matériaux à hautes performance à base d'oxydes métalliques pour applications de stockage de l'énergie“. Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAI031/document.

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Le cœur de technologie d'une batterie réside principalement dans les matériaux actifs des électrodes, qui est fondamental pour pouvoir stocker une grande quantité de charge et garantir une bonne durée de vie. Le dioxyde d'étain (SnO₂) a été étudié en tant que matériau d'anode dans les batteries Li-ion (LIB) et Na-ion (NIB), en raison de sa capacité spécifique élevée et sa bonne tenue en régimes de puissance élevés. Cependant, lors du processus de charge/décharge, ce matériau souffre d'une grande expansion volumique qui entraîne une mauvaise cyclabilité, ce qui empêche la mise en oeuvre de SnO₂ dans des accumulateurs commerciaux. Aussi, pour contourner ces problèmes, des solutions pour surmonter les limites de SnO₂ en tant qu'anode dans LIB / NIB seront présentées dans cette thèse. La partie initiale de la thèse est dédié à la production de SnO₂ et de RGO (oxyde de graphène réduit)/SnO₂ par pyrolyse laser puis à sa mise en oeuvre en tant qu'anode. La deuxième partie s'attarde à étudier l'effet du dopage de l'azote sur les performances et permet de démontrer l'effet positif sur le SnO₂ dans les LIB, mais un effet néfaste sur les NIB. La partie finale de la thèse étudie l'effet de l'ingénierie matricielle à travers la production d'un composé ZnSnO₃. Enfin, les résultats obtenus sont comparés avec l'état de l'art et permettent de mettre en perspectives ces travaux
The heart of battery technology lies primarily in the electrode material, which is fundamental to how much charge can be stored and how long the battery can be cycled. Tin dioxide (SnO₂) has received tremendous attention as an anode material in both Li-ion (LIB) and Na-ion (NIB) batteries, owing to benefits such as high specific capacity and rate capability. However, large volume expansion accompanying charging/discharging process results in poor cycleability that hinders the utilization of SnO₂ in commercial batteries. To this end, engineering solutions to surmount the limitations facing SnO₂ as an anode in LIB/NIB will be presented in this thesis. The initial part of the thesis focuses on producing SnO₂ and rGO (reduced graphene oxide)/SnO₂ through laser pyrolysis and its application as an anode. The following segment studies the effect of nitrogen doping, where it was found to have a positive effect on SnO₂ in LIB, but a detrimental effect in NIB. The final part of the thesis investigates the effect of matrix engineering through the production of a ZnSnO₃ compound. Finally, the obtained results will be compared and to understand the implications that they may possess

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Gao, Suning [Verfasser], Rudolf [Gutachter] Holze, Rudolf [Akademischer Betreuer] Holze und 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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7

Adelhelm, Philipp. „From Lithium-Ion to Sodium-Ion Batteries“. Diffusion fundamentals 21 (2014) 5, S.1, 2014. https://ul.qucosa.de/id/qucosa%3A32397.

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8

Nose, Masafumi. „Studies on Sodium-containing Transition Metal Phosphates for Sodium-ion Batteries“. 京都大学 (Kyoto University), 2016. http://hdl.handle.net/2433/215565.

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9

Clark, John. „Computer modelling of positive electrode materials for lithium and sodium batteries“. Thesis, University of Bath, 2014. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.616648.

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Providing cleaner sources of energy will require significant improvements to the solid-state materials available for energy storage and conversion technologies. Rechargeable lithium and sodium batteries are generally regarded as the best available candidates for future energy storage applications, particularly with regard to implementation within hybrid or fully electric vehicles, due to their high energy density. However, production of the next generation of rechargeable batteries will require significant improvements in the materials available for the cathode, anode and electrolyte. Modern computer modelling techniques enable valuable insights into the fundamental defect, ion transport and voltage properties of battery materials at the atomic level. Polyanionic framework materials are being investigated as alternative cathodes to LiCoO2 in Li-ion batteries largely due to their greater stability, cost and environmental benefits. In this thesis, four types of polyanion materials are examined using computational techniques. Firstly, the pyrophosphate material, Li2FeP2O7 is investigated, which has the highest voltage (3.5 V) for an iron-based phosphate cathode. In this pyrophosphate material the anti-site defect in which the Li+ and Fe2+ cations exchange positions is the intrinsic defect type found with the lowest energy. Lithium ion diffusion will follow non-linear, curved paths in the b-axis and c-axis directions, which show low migration energies. Hence, in contrast to 1D diffusion in LiFePO4, fast Li+ transport in Li2FeP2O7 is predicted to be through a 2D network in the bc-plane, which is important for good rate capability and for the function of particles without nano-sizing. Favourable doping is found for Na+ on the Li+ site, and isovalent dopants (e.g., Mn2+, Co2+, Cu2+) on the Fe2+ site; the latter could be used in attempts to increase the Fe2+/Fe3+ redox potential towards 4V. Secondly, the relative abundance and low cost associated with Na-ion batteries now make them an attractive alternative for large-scale grid storage. Therefore, defect chemistry and ion migration results are presented for the sodium-based pyrophosphate framework, Na2MP2O7 (where M = Fe, Mn). Formation energies for Na/M ion exchange are found to be higher than Li/Fe exchange, which has been related to the larger size of the Na ion compared to the Li ion. Low activation energies are found for long-range diffusion in all crystallographic directions in Na2MP2O7 suggesting three-dimensional (3D) Na-diffusion. Thirdly, the search for high voltage cathodes for lithium-ion batteries has led to recent interest in the Li2Fe(SO4)2 material which has a voltage of 3.83 V vs lithium, the highest recorded for a fluorine-free iron-based compound. Ion conduction paths through the Li2M(SO4)2 (M = Fe, Mn, Co) marinite family of cathode materials, show low activation energies for lithium migration along the a-axis channels giving rise to long-range 1D diffusion, supported by molecular dynamics (MD) simulations. Density functional theory (DFT) simulations were used to reproduce the observed high voltage of Li2Fe(SO4)2 and to make predictions of the voltages of both Li2Mn(SO4)2 and Li2Co(SO4)2, and also examine local structural distortions on lithium extraction. Finally, the layered and tavorite polymorphs of LiFeSO4OH have recently attracted interest as sustainable cathode materials offering low temperature synthesis routes. Using DFT techniques the experimental voltage and structural parameters are accurately reproduced for the tavorite polymorph. An important result for the layered structure, is that similar accuracy in both cell voltage and structure can only be obtained if a van der Waals functional is included in the DFT methodology to account for the inter-layer binding.

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Tsukamoto, Hisashi. „Synthesis and electrochemical studies of lithium transition metal oxides for lithium-ion batteries“. Thesis, University of Aberdeen, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327428.

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11

Safrany, Renard Marianne. „Propriétés électrochimiques et réponse structurale du polymorphe gamma'-V2O5 vis-à-vis de l'insertion du lithium et du sodium“. Thesis, Paris Est, 2017. http://www.theses.fr/2017PESC1185/document.

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La question du stockage de l’énergie est actuellement au cœur de nombreuses problématiques internationales. Le développement de systèmes de stockage tels que les batteries lithium ion (LIB) et sodium ion (SIB) fait donc l’objet aujourd’hui de nombreuses recherches. Dans ce contexte, les matériaux lamellaires présentant un espace inter-feuillet permettant une insertion d’espèces cationiques semblent idéals dans le cadre d’une utilisation comme matériau d’électrode positive pour ces systèmes LIB et SIB. Parmi ces structures le pentoxyde de vanadium, sous sa forme alpha est un composé modèle présentant de nombreux intérêts pour les batteries au lithium. Ce matériau présente en outre de nombreux polymorphes stables autorisant un large champ d’étude de ce composé.Dans cette thèse, nous nous sommes intéressés au polymorphe gamma’-V2O5 présentant une structure lamellaire à très large inter-feuillet laissant présager une insertion d’espèces cationiques facilitée et donc des performances électrochimiques accrues. Le but de cette thèse a consisté à étudier les propriétés électrochimiques et la réponse structurale de ce composé vis-à-vis de l’insertion des ions lithium et sodium.La première partie de cette thèse propose une analyse bibliographique de l’état de l’art sur les accumulateurs lithium-ion et sodium.Dans une seconde partie les données concernant l’insertion du lithium et du sodium dans le composé alpha-V2O5 sont présentées. Les propriétés électrochimiques et structurales de ce matériau d’insertion permettront de mettre en avant l’intérêt de l’utilisation du polymorphe gamma’-V2O5 comme matériau d’électrode positive pour les systèmes LIB et SIB.Une troisième partie de ce mémoire présente la synthèse et la caractérisation du polymorphe gamma’-V2O5. L’étude complète de ce système est présentée dans le cas de l’insertion du lithium avec une étude des performances électrochimiques, une étude cinétique de la réaction d’insertion réalisée par spectroscopie d’impédance complexe et la description des changements structuraux étudiés pas diffraction des rayons X et par spectroscopie Raman.Dans une quatrième partie, l’insertion électrochimique du sodium dans le polymorphe gamma’-V2O5 est étudiée en suivant la même démarche. Le mécanisme structural impliqué dans le fonctionnement électrochimique est résolu. La formation d’un bronze de vanadium au sodium jamais encore décrit, gamma-Na0,97V2O5, est révélée et la détermination de sa structure est réalisée. Les caractéristiques électrochimiques remarquables de gamma’-V2O5, et notamment sa tension élevée de 3,3V et son excellente stabilité en cyclages, permettent de situer ce composé parmi les cathodes les plus performantes pour batterie au sodium
The question of energy storage is currently at the heart of many international issues. The development of storage systems such as lithium ion (LIB) and sodium ion (SIB) batteries is therefore today the subject of many researches.In this context, layered materials having an interlayer space allowing insertion of cationic species seem ideal in the context of use as a positive electrode material for these LIB and SIB systems. Among these structures, vanadium pentoxide, in its alpha form, is a model compound with many advantages as an attractive cathode material for lithium batteries. This material also has numerous stable polymorphs allowing a wide field of study of this compound.In this thesis we were interested in the gamma'-V2O5 polymorph, which exhibits a layered structure with very large interlayer space allowing an easier insertion. Therefore, increased electrochemical performances are expected for this compound. The aim of this thesis was to study the electrochemical properties and the structural response of this compound toward the insertion of lithium and sodium ions.The first part of this thesis proposes a review of the current literature studies devoted to lithium-ion and sodium batteries.In a second part, a thorough study of the electrochemical lithium and sodium insertion in the alpha-V2O5 phase are depicted. The electrochemical and structural properties of alpha-V2O5 will make it possible to highlight the advantage of using the polymorph gamma'-V2O5 as a positive electrode material for LIB and SIB.The third part of this thesis presents the synthesis and characterization of the gamma'-V2O5 polymorph. The complete study of this system is presented in the case of the insertion of lithium with a study of electrochemical performances, a kinetic study of the insertion reaction carried out by complex impedance spectroscopy and a description of the structural changes studied by X-ray diffraction and by Raman spectroscopy.In the fourth chapter, the insertion of sodium into the polymorph gamma'-V2O5 is studied, using the same approach than that adopted in the case of lithium. The structural mechanism involved during the electrochemical process is solved. The formation of a new sodium vanadium bronze, gamma-Na0.97V2O5 , is revealed and its structural determination is carried out. Due to its remarkable electrochemical characteristics, especially its high voltage of 3,3V and excellent cycling stability, the gamma'-V2O5 oxide ranks among the most performant cathode materials for sodium batteries

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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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Liang, Wenfeng. „DESIGN OF ADVANCED POLYMER ELECTROLYTE FOR HIGH PERFORMANCE LITHIUM AND SODIUM BATTERIES“. University of Akron / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=akron1606172174146707.

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14

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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Morát, Julia. „Towards Stable Li-metal electrodefor rechargeable batteries“. Thesis, Uppsala universitet, Strukturkemi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-306694.

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Different types of alumina containing coatings were made on lithiumand copper in the purpose to mechanically hinder the growth ofdendrites. Lithium, coated with polymer-alumina composites wereplaced in symmetric cells for in situ studies by a light microscope.The coatings did not block the dendrites, but they did change thegrowth rate and morphology of them, probably throw both chemicalinteractions and changes in ion transportation. Also the stability ofcapacity were tested for the same coatings, the result showed abigger capacity drop for cells containing coated lithium versus cellswithout coatings.Attempted alumina coatings were also made by a solgel technique, bydirect reaction with the compound trimethylaluminium and with analumina containing acetonitrile solution.The theses also includes a study of the stability of lithium inadiponitrile. A higher amount of LiTFSI salt in adiponitrile could bythis study be reported to inhibit the dissolution of lithium that wasseen for lower salt concentrations. The dissolution appeared when thesolution was used as an electrolyte in a symmetric lithium cell. Somedifferences could be seen when the lithium surface were studied byXPS after interaction with high, low and zero concentration LiTFSI.Both the XPS studies and the absences of lithium dissolutionindicates that a more or less stable SEI had been formed.

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Wang, Miaojun. „Energetics of lithium transition metal oxides applied as cathode materials in lithium ion batteries /“. For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2005. http://uclibs.org/PID/11984.

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17

Shiraishi, Soshi. „The Study of Surface Condition Control of Lithium Metal Anode for Rechargeable Lithium Batteries“. Kyoto University, 1999. http://hdl.handle.net/2433/156984.

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本文データは平成22年度国立国会図書館の学位論文(博士)のデジタル化実施により作成された画像ファイルを基にpdf変換したものである
Kyoto University (京都大学)
0048
新制・論文博士
博士(エネルギー科学)
乙第10221号
論エネ博第7号
新制||エネ||3(附属図書館)
UT51-99-S338
(主査)教授伊藤靖彦, 教授八尾健, 教授尾形幸生
学位規則第4条第2項該当

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18

Khandelwal, Amit Harikant. „Lithium, sodium and lanthanide metal inorganic and organic salt complexes“. Thesis, University of Cambridge, 1994. https://www.repository.cam.ac.uk/handle/1810/272664.

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Heath, Jenny. „Beyond lithium : atomic-scale insights into cathode materials for sodium and magnesium rechargeable batteries“. Thesis, University of Bath, 2018. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.761000.

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The importance of energy storage worldwide is increasing with the use of renewable energy sources and electric vehicles. With the intermittent nature of wind and solar power, large-scale grid storage is an extremely important progression needed to reduce the use of fossil fuels. For this to become a reality, rechargeable batteries beyond existing Li-ion technologies need consideration. The development of such batteries requires improvement of understanding their component materials. Modern computer modelling techniques enable valuable insights into the fundamental defect, ion transport and voltage properties of battery materials at the atomic level. Atomistic simulation and ab initio density functional theory (DFT) techniques have been used to study a number of potential cathode materials for Na-ion and Mg batteries. Firstly, the olivine and maricite forms of NaFePO4 are considered in terms of their defect formation energies and Na ion diffusion. The atomistic study indicates that anti-site disorder is the most favourable type of intrinsic defect. The activation energies for Na-ion migration in the olivine and maricite materials are 0.4 eV and 1.6 – 1.8 eV respectively. Moreover, molecular dynamics (MD) studies reveal that there is only substantial Na-ion diffusion in the olivine structure, with diffusion coefficients (DNa) at 300 K of 7 x 10−13 cm2s−1 for maricite and 4 x 10−9 cm2s−1 for olivine NaFePO4. The presence of anti-site defects is shown to decrease Na+ diffusion within the olivine structure, which is of relevance to its rate behaviour. Secondly, the effect of lattice strain on ion transport and defect formation in olivine-type LiFePO4 and NaFePO4 is investigated as a means to enhance their ion conduction properties. It is predicted that lattice strain can have a remarkable effect on the rate performance of olivine cathode materials, with a major increase in ionic conductivity and decrease in blocking defectsat room temperature. Thirdly, DFT techniques have been used to examinesurface and grain boundary formation in P2-NaCoO2. The coordination lossexperienced by ions present at surfaces is found to influence the resultingsurface energy. Layered oxide cathode materials were further investigated byconsidering the effect of Mg2+ doping on P2-Na2 [Ni1 Mn2 ]O2. Na vacancy 333formation energies decreased with 10% Mg2+ doping on the Ni site and an increase in Na diffusion was predicted with MD calculations. This positive effect on Na ion conductivity is caused by displacement of the Mg ions from the transition metal layer and the resulting change in electrostatic potential. Finally, Mg ion conduction, doping and voltage behaviour of MgFeSiO4 were studied. The Mg-ion migration activation energy is relatively low for an olivine-type silicate, and MD simulations predict a diffusion coefficient (DMg) of 10−9 cm2s−1, suggesting favourable electrode kinetics. Partial substitution of Fe by Co or Mn could increase the cell voltage from 2.3 V vs Mg/Mg2+ to 2.8 - 3.0 V.

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Moore, Charles J. (Charles Jacob). „Ab initio screening of lithium diffusion rates in transition metal oxide cathodes for lithium ion batteries“. Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/79562.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2012.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 57-62).
A screening metric for diffusion limitations in lithium ion battery cathodes is derived using transition state theory and common materials properties. The metric relies on net activation barrier for lithium diffusion. Several cathode materials are screened using this approach: [beta]'-LiFePO4, hexagonal LiMnBO3, monoclinic LiMnBO3, Li 3Mn(CO3)(PO4), and Li9V3 (P2O7)3(PO4) 2. The activation barriers for the materials are determined using a combined approach. First, an empirical potential model is used to identify the lithium diffusion topology. Second, density functional theory is used to determine migration barriers. The accuracy of the empirical potential diffusion topologies, the density functional theory migration barriers, and the overall screening metric are compared against experimental evidence to validate the methodology. The accuracy of the empirical potential model is also evaluated against the density functional theory migration barriers.
by Charles J. Moore.
S.M.

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Kganyago, Khomotso R. „A Theoretical Study of Alkali Metal Intercalated Layered Metal Dichalcogenides and Chevrel Phase Molybdenum Chalcogenides“. Thesis, University of Limpopo (Turfloop Campus), 2004. http://hdl.handle.net/10386/702.

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Thesis (Ph.D. (Engineering mechanics)) --University of Limpopo, 2004
This thesis explores the important issues associated with the insertion of Mg2+ and Li+ into the solid materials: molybdenum sulphide and titanium disulphide. This process, which is also known as intercalation, is driven by charge transfer and is the basic cell reaction of advanced batteries. We perform a systematic computational investigation of the new Chevrel phase, MgxMo6S8 for 0 ≤ x ≤ 2, a candidate for high energy density cathode in prototype rechargeable magnesium (Mg) battery systems. Mg2+ intercalation property of the Mo6S8 Chevrel phase compound and accompanied structural changes were evaluated. We conduct our study within the framework of both the local-density functional theory and the generalised gradient approximation techniques. Analysis of the calculated energetics for different magnesium positions and composition suggest a triclinic structure of MgxMo6S8 (x = 1 and 2). The results compare favourably with experimental data. Band-structure calculations imply the existence of an energy gap located ~1 eV above the Fermi level, which is a characteristic feature of the electronic structure of the Chevrel compounds. Calculations of electronic charge density suggest a charge transfer from Mg to the Mo6S8 cluster, which has a significant effect on the Mo-Mo bond length. There is relatively no theoretical work, in particular ab initio pseudopotential calculations, reported in literature on structural stability, cations "site energy" calculations, and pressure work. Structures obtained on the basis from experimental studies of other ternary molybdenum sulphides are examined with respect to pressure-induced structural transformation. We report the first bulk and linear moduli of the new Chevrel phase structures. This thesis also studies the reaction between lithium and titanium disulfide, which is the perfect intercalation reaction, with the product having the same structure over the range of reaction 0  x  1 in LixTiS2. Calculated lattice parameters, bulk moduli, linear moduli, elastic constants, density of states, and Mulliken populations are reported. Our calculations confirm that there is a single phase present with an expansion of the crystalline lattice as is typical for a solid solution, about 10% perpendicular to the basal plane layers. A slight expansion of the lattice in the basal plane is also observed due to the electron density increasing on the sulfur ions. Details on the correlation between the electronic structure and the energetic (i.e. the thermodynamics) of intercalation are obtained by establishing the connection between the charge transfer and lithium intercalation into TiS2. The theoretical determination of the densities of states for the pure TiS2 and Li1TiS2 confirms a charge transfer. Lithium charge is donated to the S (3p) and Ti (3d) orbitals. Comparison with experiment shows that the calculated optical properties for energies below 12 eV agrees well with reflectivity spectra. The structural and electronic properties of the intercalation compound LixTiS2, for x = 1/4, 3/4, and 1, are also investigated. This study indicates that the following physical changes in LixTiS2 are induced by intercalation: (1) the crystal expands uniaxially in the c-direction, (2) no staging is observed. We also focus on the intercalation voltage where the variation of the cell potential with the degree of discharge for LiTiS2 is calculated. Our results show that it can be predicted with these well-developed total energy methods. The detailed understanding of the electronic structure of the intercalation compounds provided by this method gives an approach to the interpretation of the voltage composition profiles of electrode materials, and may now clearly be used routinely to determine the contributions of the anode and cathode processes to the cell voltage. Hence becoming an important tool in the selection and design of new systems. Keywords Magnesium rechargeable battery; Chevrel, Lithium batteries; Li and Mg-ion insertion; TiS2; Mo6S8; Charge transfer; reflectivity, intercalation, elastic constants, voltage, EOS, Moduli.
the National Research Foundation, the Royal Society(U.K),the Council for Scientific and Industrial Research,and Eskom

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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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Budak, Öznil [Verfasser]. „Metal oxide / carbon hybrid anode materials for lithium-ion batteries / Öznil Budak“. Saarbrücken : Saarländische Universitäts- und Landesbibliothek, 2020. http://d-nb.info/1232726214/34.

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Lubke, Mechthild. „Nano-sized transition metal oxide negative electrode materials for lithium-ion batteries“. Thesis, University College London (University of London), 2018. http://discovery.ucl.ac.uk/10044227/.

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This thesis focuses on the synthesis, characterization and electrochemical evaluation of various nano-sized materials for use in high power and high energy lithium-ion batteries. The materials were synthesised via a continuous hydrothermal flow synthesis (CHFS) process, which is a single step synthesis method with many advantages including screening processes (chapter 5). Electrochemical energy storage is introduced in chapter 1, with a focus on high power and high energy negative electrode materials for lithium-ion batteries (and capacitors). Many different classes of materials are discussed with associated advantages and disadvantages. This is followed by an experimental section in chapter 2. Chapter 3 deals with the main question regarding why some high power insertion materials show a wider operational potential window than expected. The nature of this electrochemical performance is discussed and classified towards battery-like and supercapacitor-like behaviour. Chapter 4 deals with Nb-doped anatase TiO2, which was tested for high power insertion materials. The role of the dopant was discussed in a comprehensive study. Chapter 5 gives an excellent example how CHFS processes can help accurately answer a scientific question. In this case the question dealt with the impact of transition metal dopants on the electrochemical performance of SnO2. Since CHFS enables similar materials properties despite doping, the real impact could be investigated in a fair manner. Finally, chapter 6 shows a strategy of achieving higher energy simultaneously with high cycle life. Insertion materials are combined with alloying materials in a simple, single step synthesis and this showed increased capacity, which is essential for high energy.

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Alwast, Dorothea [Verfasser]. „Electrochemical Model Studies on Metal-air and Lithium-ion Batteries / Dorothea Alwast“. Ulm : Universität Ulm, 2021. http://d-nb.info/1237750822/34.

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Ji, Yijie. „Metal Organic Frameworks Derived Nickel Sulfide/Graphene Composite for Lithium-Sulfur Batteries“. University of Akron / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=akron152233332526446.

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Howlett, Patrick C. „Room temperature ionic liquids as electrolytes for use with the lithium metal electrode“. Monash University, School of Chemistry, 2004. http://arrow.monash.edu.au/hdl/1959.1/9629.

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Posch, P., P. Bottke, M. Wilkening und 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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Zhao, Teng. „Development of new cathodic interlayers with nano-architectures for lithium-sulfur batteries“. Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/275684.

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Issues with the dissolution and diffusion of polysulfides in liquid organic electrolytes hinder the advance of lithium–sulfur (Li-S) batteries for next generation energy storage. To trap and re-utilize the polysulfides, brush-like, zinc oxide (ZnO) nanowires based interlayers were prepared ex-situ using a wet chemistry method and were coupled with a sulfur/multi-walled carbon nanotube (S/MWCNT) composite cathode. The cell with this configuration showed a good cycle life at a high current rate ascribed to (a) a strong interaction between the polysulfides and ZnO nanowires grown on conductive substrates; (b) fast electron transfer and (c) an optimized ion diffusion path from a well-organized nanoarchitecture. A praline-like flexible interlayer consisting of titanium oxide (TiO2) nanoparticles and carbon (C) nanofiber was further prepared in-situ using an electrospinning method, which allows the chemical adsorption of polysulfides throughout a robust conductive film. A significant enhancement in cycle stability and rate capability was achieved by incorporating this interlayer with a composite cathode of S/MWCNT. These results herald a new approach to building functional interlayers by integrating metal oxides with conductive frameworks. The derivatives of the TiO2/C interlayer was synthesized by changing the precursor concentration and carbonization temperature. Finally, a dual-interlayer was fabricated by simply coating titanium nitride (TiN) nanoparticles onto an electro-spun carbon nanofiber mat, which was then sandwiched with a sulfur/assembled Ketjen Black (KB) composite cathode with an ultra-high sulfur loading. The conductive polar TiN nanoparticles not only have a strong chemical affinity to polysulfides through a specific sulfur-nitrogen bond but also improve the reaction kinetics of the cell by catalyzing the conversion of the long-chain polysulfides to lithium sulfide. Besides, carbon nanofiber mat ensures mechanical robustness to TiN layer and acts as a physical barrier to block polysulfides diffusion. The incorporation of dual interlayers with sulfur cathodes offers a commercially feasible approach to improving the performance of Li-S batteries.

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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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Steiger, Jens [Verfasser], und O. [Akademischer Betreuer] Kraft. „Mechanisms of Dendrite Growth in Lithium Metal Batteries / Jens Steiger. Betreuer: O. Kraft“. Karlsruhe : KIT-Bibliothek, 2015. http://d-nb.info/106673691X/34.

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Henriques, Alexandra J. „Nano-Confined Metal Oxide in Carbon Nanotube Composite Electrodes for Lithium Ion Batteries“. FIU Digital Commons, 2017. http://digitalcommons.fiu.edu/etd/3169.

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Lithium ion batteries (LIB) are one of the most commercially significant secondary batteries, but in order to continue improving the devices that rely on this form of energy storage, it is necessary to optimize their components. One common problem with anode materials that hinders their performance is volumetric expansion during cycling. One of the methods studied to resolve this issue is the confinement of metal oxides with the interest of improving the longevity of their performance with cycling. Confinement of metal oxide nanoparticles within carbon nanotubes has shown to improve the performance of these anode materials versus unconfined metal oxides. Here, electrostatic spray deposition (ESD) is used to create thin films of nano-confined tin oxide/CNT composite as the active anode material for subsequent property testing of assembled LIBs. This thesis gives the details of the techniques used to produce the desired anode materials and their electrochemical characterization as LIB anodes.

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Tian, Guiying [Verfasser], und H. [Akademischer Betreuer] Ehrenberg. „Study on lithium ion migration in the composite solid electrolyte for lithium metal batteries / Guiying Tian ; Betreuer: H. Ehrenberg“. Karlsruhe : KIT-Bibliothek, 2019. http://d-nb.info/1177147157/34.

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Limthongkul, Pimpa 1975. „Phase transformations and microstructural design of lithiated metal anodes for lithium-ion rechargeable batteries“. Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/8443.

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Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2002.
Includes bibliographical references.
There has been great recent interest in lithium storage at the anode of Li-ion rechargeable battery by alloying with metals such as Al, Sn, and Sb, or metalloids such as Si, as an alternative to the intercalation of graphite. This is due to the intrinsically high gravimetric and volumetric energy densities of this type of anodes (can be over an order of magnitude of that of graphite). However, the Achilles' heel of these Li-Me alloys has been the poor cyclability, attributed to mechanical failure resulting from the large volume changes accompanying alloying. Me-oxides, explored as candidates for anode materials because of their higher cyclability relative to pure Me, suffer from the problem of first cycle irreversibility. In both these types of systems, much experimental and empirical data have been provided in the literature on a largely comparative basis (i.e. investigations comparing the anode behavior of some new material with older candidates). It is the belief of the author that, in order to successfully proceed with the development of better anode materials, and the subsequent design and production of batteries with better intrinsic energy densities, a fundamental understanding of the relationship between the science and engineering of anode materials must be achieved, via a systematic and quantitative investigation of a variety of materials under a number of experimental conditions. In this thesis, the effects of composition and processing on microstructure and subsequent electrochemical behavior of anodes for Li-ion rechargeable batteries were investigated, using a number of approaches.
(cont.) First, partial reduction of mixed oxides including Sb-V-O, Sb-Mn-O, Ag-V-O, Ag-Mn-O and Sn-Ti-O, was explored as a method to produce anode materials with high cyclability relative to pure metal anodes, and decreased first cycle irreversibility relative to previously produced metal-oxides. The highest cyclability was achieved with anode materials where the more noble metal of the mixed oxide was reduced internally, producing nanoscale active particles which were passivated by an inactive matrix. Second, a systematic study of various metal anode materials, including Si, Sn, Al, Sb and Ag, of different starting particle sizes was undertaken, in order to better understand the micromechanical mechanisms leading to poor cyclability in these pure metals. SEM of these materials revealed fracture in particles of > 1 pm after a single discharge/charge cycle, consistent with literature models which predict such fracture due to volumetric strains upon lithiation. However, TEM of these materials revealed a nanocrystalline structure after one cycle that in some metals was mixed with an amorphous phase. STEM of anode materials after 50 cycles revealed a dissociation of this nanostructure into nanoparticles, suggesting a failure mechanism other than volumetric strains, such as chemical attack. Finally, the appearance of the amorphous phase was investigated in lithiated Si, Sn, Ag and Al metal anode systems. A new mechanism, electrochemically-induced solid-state amorphization was proposed and explored via experiments using calibrated XRD and TEM. Experimental observations of these various Me systems subjected to different degrees of lithiation supported such phenomenon...
by Pimpa Limthongkul.
Ph.D.

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Shao, Yunfan. „Highly electrochemical stable quaternary solid polymer electrolyte for all-solid-state lithium metal batteries“. University of Akron / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=akron1522332577785545.

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Nilsson, Viktor. „Highly Concentrated Electrolytes for Lithium Batteries : From fundamentals to cell tests“. Licentiate thesis, Chalmers University of Technology, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-351339.

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The electrolyte is a crucial part of any lithium battery, strongly affecting longevity and safety. It has to survive rather severe conditions, not the least at the electrode/electrolyte interfaces. Current commercial electrolytes based on 1 M LiPF 6 in a mixture of organic solvents balance the requirements on conductivity and electrochemical stability, but they are volatile and degrade when operated at temperatures above ca. 70°C. The salt could potentially be replaced with e.g. LiTFSI, but corrosion of the aluminium current collector is an issue. Replacing the graphite negative electrode by Li metal for large gains in energy density challenges the electrolyte further by exposing it to freshly deposited Li, leading to poor coulombic efﬁciency (CE) and consumption of both Li and electrolyte. Highly concentrated electrolytes (up to > 4 M) have emerged as a possible remedy, by a changed solvation structure such that all solvent molecules are coordinated to cations – leading to a lowered volatility and melting point, an increased charge carrier density and electrochemical stability, but a higher viscosity and a lower ionic conductivity. Here two approaches to highly concentrated electrolytes are evaluated. First, LiTFSI and acetonitrile electrolytes with respect to increased electrochemical stability and in particular the passivating solid electrolyte interphase (SEI) on the anode is studied using electrochemical techniques and X-ray photoelectron spectroscopy. Second, lowering the liquidus temperature by high salt concentration is utilized to create an electrolyte solely of LiTFSI and ethylene carbonate, tested for application in Li metal batteries by characterizing the morphology of plated Li using scanning electron microscopy and the CE by galvanostatic polarization. While the ﬁrst approach shows dramatic improvements, the inherent weaknesses cannot be completely avoided, the second approach provides some promising cycling results for Li metal based cells. This points towards further investigations of the SEI, and possibly long-term safe cycling of Li metal anodes.
Elektrolyten är en fundamental del av ett litiumbatteri som starkt påverkar livslängden och säkerheten. Den måste utstå svåra förhållanden, inte minst vid gränsytan mot elektroderna. Dagens kommersiella elektrolyter är baserade på 1 M LiPF 6 i en blandning av organiska lösningsmedel. De balanserar kraven på elektrokemisk stabilitet och jonledningsförmåga, men de är lättﬂyktiga och bryts ned när de används vid temperaturer över ca. 70°C. Saltet skulle kunna bytas ut mot t.ex. LiTFSI, vilket ökar värmetåligheten avsevärt, men istället uppstår problem med korrosion på den strömsamlare av aluminium som används för katoden. Genom att byta ut graﬁtanoden i ett Li-jonbatteri mot en folie av litiummetall kan man öka energitätheten, men då litium pläteras bildas ständigt nya Li-ytor som kan reagera med elektrolyten. Detta leder till en låg coulombisk effektivitet genom nedbrytning av både Li och elektrolyt. Högkoncentrerade elektrolyter har en mycket hög saltkoncentration, ofta över 4 M, och har lags fram som en möjlig lösning på många av de problem som plågar denna och nästa generations batterier. Dessa elektrolyter har en annorlunda lösningsstruktur, sådan att alla lösningsmedelsmolekyler koordinerar till katjoner – vilket leder till att de blir mindre lättﬂyktiga, får en ökad täthet av laddningsbärare, och en ökad elektrokemisk stabilitet. Samtidigt får de en högre viskositet och lägre jonledningsförmåga. Här har två angreppssätt för högkoncentrerade elektrolyter utvärderats. I det första har acetonitril, som har begränsad elektrokemisk stabilitet och ett högt ångtryck, blandats med LiTFSI för en uppsättning av elektrolyter med varierande koncentration. Dessa har testats i Li-jonbatterier och i synnerhet den passiverande ytan på graﬁtelektroder har undersökts med både röntgen-fotoelektronspektroskopi (XPS) och elektrokemiska metoder. En markant förbättring av den elektrokemiska stabiliteten observeras, men de inneboende bristerna hos elektrolyten kan inte kompenseras fullständigt, vilket skapar tvivel på hur väl detta kan fungera i en kommersiell cell. Med det andra angreppssättet har hög saltkoncentration nyttjats för sänka smältpunkten för en elektrolyt baserad på etylenkarbonat, som annars inte kan används som enda lösningsmedel. Dessa elektrolyter har testats för användning i Limetall-batterier genom långtidstest, mätning av den coulombiska effektiviteten och analys av deponerade Li-ytor med svepelektronmikroskop. Resultaten är lovande, med över 250 cykler på 0.5 mAh/cm2 och en effektivitet på över 94%, men framförallt observeras en mycket jämnare deponerad Li-yta, vilket kan möjliggöra säker cykling av Li-metall-batterier. Ett logiskt nästa steg är studier av Liytan med t.ex. XPS för att utröna vad som skiljer den från ytan som bildats i en 1 M referenselektrolyt.

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Li, Wei. „Sol-gel synthesis of TiO2 anatase in a fluorinated medium and its applications as negative electrode for Li+ and Na+ batteries“. Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066238/document.

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Le dioxyde de titane (TiO2) est un matériau polyvalent qui présente des propriétés intéressantes allant de la catalyse au stockage et conversion d'énergie. Afin d'améliorer ses propriétés physico-chimiques, plusieurs approches ont été appliquées telles que, la réduction de la taille des particules, modification de la morphologie, le dopage par d'autres éléments. Dans cette thèse, une nouvelle méthode de synthèse basée sur la chimie de sol-gel est développée en milieu fluoré. Les anions divalents de O2- dans TiO2 anatase sont substitués par anions monovalents de F- et OH-, le déficit de charge négative est compensée par la création simultanée de lacunes cationiques dont la concentration peut être réglés par la température de réaction. La nouvelle famille de matériaux polyanioniques a la composition générale de Ti1-x-y•x+yO2-4(x+y)F4x(OH)4y avec de lacune cationique jusqu’à 22 %. Le matériau considérablement dopé maintient son réseau cristallin original et montre une structure locale unique. Son mécanisme de formation est étudié à l'échelle atomique. Les effets des paramètres de synthèse sur la structure, la morphologie et la composition chimique de la phase obtenue sont étudiés en détail. Lorsqu'il est utilisé comme anode pour batteries aux ions lithium, l'anatase fluorée lacunaire montre des performances supérieures pour le stockage de lithium, surtout à haute régime de charge/décharge. La présence de lacune modifie le mécanisme d'insertion du lithium par rapport à TiO2 anatase stœchiométrique: une réaction de solution solide a été trouvé à la place une réaction diphasique, soulignant l'impact de la modification de la structure sur les propriétés électrochimiques vis-à-vis au Li+. Enfin, le mécanisme d'insertion de sodium dans anatase stœchiométrique et lacunaire est étudié. Des aperçus sans précédent sont acquis pour la réaction d’insertion de Na+
Titanium dioxide (TiO2) is a multifunctional material and presents promising properties ranging from catalysis to energy storage and conversion. In order to obtain enhanced physico-chemical properties, several approaches were applied such as, reducing particle sizes, modifying morphology, doping with other elements. In this thesis, a new synthesis method based on sol-gel chemistry is developed in fluorinated medium. The divalent O2- in TiO2 anatase is substituted by monovalent F- and OH- anions, the deficiency of negative charge is counterbalanced by the simultaneous formation of cationic Ti4+ vacancies (•) which can be tuned by the reaction temperature. The new family of polyanionic materials has the general composition of Ti1-x-y•x+yO2-4(x+y)F4x(OH)4y with up to 22 % of cationic vacancies. The drastically doped material keeps its original crystalline network and shows unique local structure. Its formation mechanism is investigated at atomic scale. The effects of synthesis parameters on structure, morphology and chemical composition of the resulting phase are studied in details. When used as anode for lithium-ion batteries, the cation-defected fluorinated anatase shows superior lithium storage performance, especially at high charge/discharge rate. The presence of vacancy modifies lithium insertion mechanism compared to stoichiometric TiO2 anatase: a solid solution reaction was found instead a well-known two-phase reaction, highlighting the impact of structure modification on the electrochemical properties vs. Li+. Sodium insertion mechanism into stoichiometric and defective anatase are studied at the last. Unprecedented insights into Na+ insertion reaction are gained

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Zhang, Yuhan. „POLYMER ELECTROLYTES FOR HIGH CURRENT DENSITY LITHIUM STRIPPING/PLATING TEST“. University of Akron / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=akron1555090752890092.

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Courtney, Ian Anthony. „The physics and chemistry of metal oxide composites as anode materials for lithium-ion batteries“. Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape9/PQDD_0021/NQ49253.pdf.

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Owen, Nathan. „The investigation of a non-transition metal fluoride as a cathode material for lithium batteries“. Thesis, Cranfield University, 2012. http://dspace.lib.cranfield.ac.uk/handle/1826/10237.

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Lithium ion batteries are fast becoming the consumer choice for powering their electronic devices. However, current lithium batteries energy densities are not suf- ﬁciently high, and cost per kWh suﬃciently low, to be widely accepted as batteries in electric vehicles. In order to reduce the cost and increase the energy density it may be necessary to move away from intercalation electrode materials, that are limited by the number of vacant lithium interstitial sites available, to conversion reaction materials that can allow multiple electron transfer. This thesis looks to investigate the use of a non- transition metal ﬂuoride as a cathode material in a primary or secondary lithium battery. Initial results for the ball milled material show speciﬁc energy densities over 2050 Wh/kg. The initial energy density rapidly faded over a period of a few cycles due to the structural change of the material and unwanted reactions with the electrolyte. These were identiﬁed by investigating the mechanism of the one stage discharge and charge proﬁle. To further improve the cycling results nanorods were synthesised which improved the rate capability to provide an energy density of over 1250 Wh/kg at a discharge rate of 0.25C. The capacity over repeated cycling was also improved but the same problems that plagued the ball milled samples were also apparent in the nanorod samples. It was found during the initial investigation of the non-transition metal ﬂuoride material that it is rechargeable, but for a limited number of cycles partly due to its poor kinetics. It has the potential to be a good rechargeable battery material but if not can satisfactorily compete with commercial primary batteries in terms of energy density and cost, as it is a very cheap material.

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Lu, Xiaoxiao. „The improvement of electrochemical performance of SnO2-based nanocomposites as anodes for lithium ion and sodium ion batteries“. Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/the-improvement-of-electrochemical-performance-of-sno2based-nanocomposites-as-anodes-for-lithium-ion-and-sodium-ion-batteries(d0d78e2a-2ed4-4274-b3fe-9c018992e15a).html.

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Nowadays, low carbon economy becomes a significant topic over the world. Due to the decreasing amount of fossil energy source and the worsening environmental pollution, traditional energy sources should be transferred to renewable energy sources. A transition to renewable energy will require radical changes to systems and technologies for energy storage. Lithium ion (Li-ion) batteries are now considered as the most important electrochemical energy source for portable devices, electrical vehicles and expected to be used in grid electrical energy storage. Beside on Li-ion batteries, sodium ion (Na-ion) batteries are another promising energy source, which have the advantages in cost, safety and environmental factors, and they could be used for stationary energy storage systems and large vehicles. Tin-based nanocomposites are promising to replace the traditional graphite for Li-ion batteries to achieve a higher battery performance. In 2005, Sony Corporation launched the first Sn-based anode Li-ion batteries (Nexelion) to obtain a 50% increase in volumetric capacity over the conventional battery, which marked Li-ion batteries to enter into a new cutting edge. However, Sn-based materials faced with challenges. The battery performance was limited by a low cycling life and low rate performance, and methods should be devised to overcome these shortcomings. In this thesis, SnO2-based nanocomposites, including the graphene-SnO2, the carbon-coated graphene-SnO2 and the carbon-coated nanostructured SnO2 have been prepared and investigated as anodes for Li-ion and Na-ion batteries. The microstructure, electrochemical performances and even the degradation mechanisms have been investigated as the effects for different composite materials. Chapter 4 reports an amorphous carbon coated graphene-SnO2 composite which exhibited an enhanced cycling stability. In previous researches, the performance enhancements of that type of materials were commonly attributed to the carbon coating enhancing the electronic conductivity. However, it is found that the carbon coating deeply relates to the microstructure stability of the active materials, the performance enhancement can be attributed to the enhancement of structural stability. Chapter 5 reports same composites with various graphene to amorphous carbon mass ratios. In this chapter, we try to find out the optimized composition and understanding the different roles of graphene and amorphous carbon in that type of composites. It is found that an optimised graphene to carbon mass ratio can effectively enhance the structural stability and the electrode conductivity. Chapter 6 reports a carbon-coated flower-like nanostructured SnO2 for Na-ion battery application, which has been demonstrated to have a high reversible capacity and high rate performance. The carbon coating is found to help in the formation of a high quality solid electrolyte interface (SEI) layer on the surface of the active materials. These researches focus on modifying SnO2 and SnO2-based materials by carbon coating technologies, which aim to develop novel electrode materials to obtain a better battery performance for Li-ion and Na-ion batteries.

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Chappel, Eric. „Magnétisme de quelques oxydes bidimensionnels de la famille AMO2 (A=Li, Na ; M=Ni, Fe, Co)“. Université Joseph Fourier (Grenoble), 2000. http://www.theses.fr/2000GRE10081.

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Ce memoire de these presente une etude des proprietes magnetiques de quelques oxydes lamellaires de la famille amo 2 (a=li, na ; m=ni, fe, co) qui presentent par ailleurs des applications en tant que materiaux d'electrodes positives dans les batteries lithium-ion. Parmi ces composes, linio 2 avait deja fait l'objet de nombreuses etudes magnetiques mais la grande disparite des resultats obtenus n'avait permis de degager aucun consensus quant a la nature de son etat fondamental. Afin d'ameliorer les performances des batteries, les chimistes du solide ont considerablement ameliore les conditions de synthese et de caracterisations physico-chimiques au cours de ces dernieres annees. Il s'est revele que l'ecart a la stchiometrie des materiaux etudies avait des consequences dramatiques a la fois sur les proprietes magnetiques et electrochimiques. Dans un premier temps, les proprietes magnetiques du compose nanio 2 parfaitement lamellaire ont donc ete etudiees par rpe, diffraction neutronique et mesures d'aimantation a hauts champs et de susceptibilite en champs faibles. Nanio 2 est un af de type a qui presente un ordre orbital de type ferro pour t<210\c du a l'effet jahn-teller cooperatif des ions ni 3 + de spin s=1/2. Une etude detaillee des phases li 1 xni 1 + xo 2 en fonction de la concentration x nous a permis de montrer le role fondamental des ions ni excedentaires qui forment des clusters magnetiques. Nous proposons un modele original de frustration induite par les clusters pour x petit qui rend compte de toutes les donnees experimentales. Nous abordons finalement les effets de la substitution cationique du cobalt dans lifeo 2 et du fer dans linio 2. Nous montrons que le fer sur le site du lithium ne participe pas a la formation de clusters magnetiques. Dans tous les cas, la valeur et le signe des interactions ont ete estimes.

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Ohira, Koji. „Systematic survey of phosphate materials for lithium-ion batteries by first principle calculations“. Master's thesis, 京都大学 (Kyoto University), 2013. http://hdl.handle.net/2433/180500.

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Ngo, Hoang Phuong Khanh. „Développement et caractérisation des électrolytes plus sûrs et versatiles pour les batteries au lithium métallique ou post-lithium“. Thesis, Université Grenoble Alpes (ComUE), 2019. http://www.theses.fr/2019GREAI076.

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Les problèmes de sécurité liés aux fuites de produits chimiques, au chauffage externe ou aux explosions sont un frein au développement de dispositifs de stockage renouvelables à base d’électrolytes liquides. La sécurité des batteries nécessite le développement de nouvelles technologies telles que les électrolytes à base de liquide ionique ou de membranes polymères conductrices. Simultanément, et face à l’épuisement des ressources en lithium, la tendance énergétique cherche à privilégier le développement de piles rechargeables à base d’éléments abondants, tels que les métaux alcalins / alcalino-terreux. Une meilleure compréhension du comportement conducteur cationique de ces électrolytes est nécessaire pour développer des batteries au lithium et post-lithium de haute sécurité.Le premier objectif de ce travail était axé sur les propriétés de transport dans des électrolytes liquides ioniques obtenus en dissolvant des sels alcalin/alcalino-terreux dans un liquide ionique, le BMIm TFSI. Ces mélanges possèdent des caractéristiques prometteuses telles qu'une faible tension de vapeur, une ininflammabilité, une stabilité thermique élevée et une bonne conductivité ionique. Ces électrolytes ont été étudiés par une appoche multitechnique pour une description thermodynamique (propriétés thermiques), dynamique (viscosité, conductivité ionique, coefficients d'auto-diffusion des différentes espèces) et structurale (spectroscopies IR et Raman). Ces travaux ont permis de montrer que le comportement du transport cationique dans ces électrolytes liquide-ionique est fortement influencé par la natutre et la concentration des cations. Ces variations dépendent de la viscosité, qui sont reliés à la sphère de coordination des ions alcalins/alcalino-terreux dissous.Un autre partie de ce travail présente le développement de nouveaux ionomères à base de POE comme électrolytes solides pour des batteries rechargeables au lithium ou de génération post-lithium. Ces matériaux, ionomères réticulés et copolymères, présentent un nombre de transport ionique pratiquement égal à 1. L'excellent comportement en cyclage dans une batterie symétrique au lithium-métallique ont confirmé le bon comportement de l'électrolyte et une réversibiité parfaite de l'intercalation/désintercalation du lithium dans les deux électrodes. Les hautes performances des batteries au lithium métallique utilisant des cathodes LiFePO4, ont confirmé l'adéquation de ces matériaux pour une utilisation en tant qu'électrolytes solides. Un dernier objectif de ce travail a été l'étude du comportement de conductivité des cations alcalins dans différentes matrices de polymère. Grâce au greffage des fonctions anionique, une conductivité cationique unitaire a pu être atteinte, ce qui a permis de mesurer l'effet de la taille du cation sur sa mobilité
Safety issues related to chemical leakage, external heating, or explosion restrain the advancement of renewable storage devices based on classical liquid electrolytes. The urgent need for safer batteries requires new technologies such as the replacement of carbonate solvents by green ionic liquid-based electrolytes or the use of conducting polymer membranes. Moreover, facing a future shortage of raw materials such as lithium, trends are to promote the development of rechargeable batteries based on abundant elements i.e. alkali/alkaline-earth metals. A better understanding of cation conductive behavior in these electrolytes become the mainstream for developing high-security lithium and post-lithium batteries.In this work, the first goal was to focus on the physical and ionic transport properties of several binary systems based on the solution of different alkali/alkaline-earth TFSI salts in a common ionic liquid BMIm TFSI. These ionic liquid electrolytes possess unique characteristics that are promising for electrolyte applications e.g. low vapor pressure, non-inflammable, high thermal stability, with sufficient ionic conductivity. These mixtures are studied with the multi-technique approach to reach thermodynamics (thermal properties), dynamics (viscosity, ionic conductivity self-diffusion coefficients) and structural (IR and Raman spectroscopy) description of these systems. The cationic transport behavior in these ionic liquid electrolytes is strongly influenced by the nature of the cation and its concentration. These viscosity dependent phenomena are related to the alkali/alkaline-earth coordination shell.Another goal of this work is the development of new single-ion conducting polymers based on PEO as solid electrolytes for safer lithium and post-lithium rechargeable batteries. These materials exhibit a cation transference number which nearly reaches unity for the cross-linked ionomers and multi-block copolymers. The cycling tests in symmetric lithium-metal cell affirmed the reversibility of electrolyte with stable lithium plating/stripping between two electrodes. High performances in lithium metal batteries using ‘home-made’ LiFePO4 cathodes demonstrate the potential of these materials as solid electrolytes. An ultimate aim showed the conductivity behavior of the alkali cations in the different polymer matrix. Thanks to the grafting anionic function distributed along the polymer chain, the effect of cation size on its mobility were clearly observed

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Popa, Andreia Ioana. „Electrochemistry and magnetism of lithium doped transition metal oxides“. Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-26029.

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The physics of transition metal oxides is controlled by the combination and competition of several degrees of freedom, in particular the charge, the spin and the orbital state of the electrons. One important parameter responsible for the physical properties is the density of charge carriers which determines the oxidization state of the transition metal ions. The central objective in this work is the study of transition metal oxides in which the charge carrier density is adjusted and controlled via lithium intercalation/deintercalation using electrochemical methods. Lithium exchange can be achieved with a high degree of accuracy by electrochemical methods. The magnetic properties of various intermediate compounds are studied. Among the materials under study the mixed valent vanadium-oxide multiwall nanotubes represent a potentially technologically relevant material for lithium-ion batteries. Upon electron doping of VOx-NTs, the data confirm a higher number of magnetic V4+ sites. Interestingly, room temperature ferromagnetism evolves after electrochemical intercalation of Li, making VOx-NTs a novel type of self-assembled nanoscaled ferromagnets. The high temperature ferromagnetism was attributed to formation of nanosize interacting ferromagnetic spin clusters around the intercalated Li ions. This behavior was established by a complex experimental study with three different local spin probe techniques, namely, electron spin resonance (ESR), nuclear magnetic resonance (NMR) and muon spin relaxation spectroscopies. Sr2CuO2Br2 was another compound studied in this work. The material exhibits CuO4 layers isostructural to the hole-doped high-Tc superconductor La2-xSr2CuO4. Electron doping is realized by Li-intercalation and superconductivity was found below 9K. Electrochemical treatment hence allows the possibility of studying the electronic phase diagram of LixSr2CuO2Br2, a new electron doped superconductor. The effect of electrochemical lithium doping on the magnetic properties was also studied in tunnel-like alpha-MnO2 nanostructures. Upon lithium intercalation, Mn4+ present in alpha-MnO2 will be reduced to Mn3+, resulting in a Mn mixed valency in this compound. The mixed valency and different possible interactions arising between magnetic spins give a complexity to the magnetic properties of doped alpha-MnO2.

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Popa, Andreia Ioana. „Electrochemistry and magnetism of lithium doped transition metal oxides“. Doctoral thesis, Leibniz-Institut für Festkörper- und Werkstoffforschung Dresden, 2009. https://tud.qucosa.de/id/qucosa%3A25180.

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The physics of transition metal oxides is controlled by the combination and competition of several degrees of freedom, in particular the charge, the spin and the orbital state of the electrons. One important parameter responsible for the physical properties is the density of charge carriers which determines the oxidization state of the transition metal ions. The central objective in this work is the study of transition metal oxides in which the charge carrier density is adjusted and controlled via lithium intercalation/deintercalation using electrochemical methods. Lithium exchange can be achieved with a high degree of accuracy by electrochemical methods. The magnetic properties of various intermediate compounds are studied. Among the materials under study the mixed valent vanadium-oxide multiwall nanotubes represent a potentially technologically relevant material for lithium-ion batteries. Upon electron doping of VOx-NTs, the data confirm a higher number of magnetic V4+ sites. Interestingly, room temperature ferromagnetism evolves after electrochemical intercalation of Li, making VOx-NTs a novel type of self-assembled nanoscaled ferromagnets. The high temperature ferromagnetism was attributed to formation of nanosize interacting ferromagnetic spin clusters around the intercalated Li ions. This behavior was established by a complex experimental study with three different local spin probe techniques, namely, electron spin resonance (ESR), nuclear magnetic resonance (NMR) and muon spin relaxation spectroscopies. Sr2CuO2Br2 was another compound studied in this work. The material exhibits CuO4 layers isostructural to the hole-doped high-Tc superconductor La2-xSr2CuO4. Electron doping is realized by Li-intercalation and superconductivity was found below 9K. Electrochemical treatment hence allows the possibility of studying the electronic phase diagram of LixSr2CuO2Br2, a new electron doped superconductor. The effect of electrochemical lithium doping on the magnetic properties was also studied in tunnel-like alpha-MnO2 nanostructures. Upon lithium intercalation, Mn4+ present in alpha-MnO2 will be reduced to Mn3+, resulting in a Mn mixed valency in this compound. The mixed valency and different possible interactions arising between magnetic spins give a complexity to the magnetic properties of doped alpha-MnO2.

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Inamoto, Jun-ichi, und Junichi Inamoto. „Electrochemical Characterization of Surface-State of Positive Thin-Film Electrodes in Lithium-Ion Batteries“. Kyoto University, 2017. http://hdl.handle.net/2433/226784.

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Gao, Shuang. „INVESTIGATION OF TRANSITION-METAL IONS IN THE NICKEL-RICH LAYERED POSITIVE ELECTRODE MATERIALS FOR LITHIUM-ION BATTERIES“. UKnowledge, 2019. https://uknowledge.uky.edu/cme_etds/100.

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Layered lithium transition-metal oxides (LMOs) are used as the positive electrode material in rechargeable lithium-ion batteries. Because transition metals undergo redox reactions when lithium ions intercalate in and disintercalate from the lattice, the selection and composition of transition metals largely influence the electrochemical performance of LMOs. Recently, a Ni-rich compound, LiNi0.8Co0.1Mn0.1O2 (NCM811), has drawn much attention. It is expected to replace its state-of-the-art cousins, LiCoO2 (LCO) and LiNi1/3Co1/3Mn1/3O2 (NCM111), because of its higher capacity, lower cost, and reduced toxicity. However, the excess Ni, as a transition-metal element in NCM811, can cause structural and cycling instability. Starting from NCM811, I modified the composition of transition metals by two approaches: 1) introducing cobalt deficiency and 2) substituting Ni, Co, and Mn with Zr. Their influences on the phase, structure, cycling performance, rate capability, and ionic transport were investigated by a variety of characterization techniques. I found that cobalt non-stoichiometry can suppress Ni2+/Li+ cation mixing, but simultaneously promotes the formation of oxygen vacancies, leading to rapid capacity fade and inferior rate capability compared to pristine NCM811. On the other hand, Zr can reside on and expand the lattice of NCM811, and form Li-rich lithium zirconates on their surfaces. In particular, 1% Zr substitution can increase the stability of NCM811 and facilitate Li-ion transport, resulting in enhanced cycling durability and high-rate performance. My studies help improve the understanding of the effects of transition metals on the degradation of the Ni-rich layered positive electrode material and provide modification strategies to enhance its performance and durability for Li-ion battery applications.

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Wenzel, Sebastian [Verfasser]. „Thermodynamic and kinetic instability of inorganic solid electrolytes at lithium and sodium metal electrodes / Sebastian Wenzel“. Gießen : Universitätsbibliothek, 2016. http://d-nb.info/1119660114/34.

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Purushothaman, Bushan K. „DEVELOPMENT OF BATTERIES FOR IMPLANTABLE APPLICATIONS“. Case Western Reserve University School of Graduate Studies / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=case1151609663.

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