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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 PhilosophyDepartment 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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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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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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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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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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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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Berti, Nicola. "MgH2-TiH2 hydrides as negative electrodesof Li-ion batteries." Thesis, Paris Est, 2017. http://www.theses.fr/2017PESC1029/document.
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Les batteries lithium-ion sont aujourd’hui très utilisées pour alimenter l’électronique portable telle que les ordinateurs, les smartphones et les caméras. Cependant, de nouvelles applications telles que les véhicules électriques et les systèmes stationnaires de stockage d'énergie nécessitent des batteries à performances améliorées. En particulier, de nouveaux matériaux d'électrode avec des densités d'énergie plus élevées sont requis. Les hydrures de MgH2 et TiH2 et leurs mélanges possèdent de très fortes capacités électrochimiques (>1 Ah/g). Ils ont été étudiés comme matériaux d’électrode négative dans les batteries Li-ion. La réaction de conversion de ces hydrures avec du lithium et les changements structuraux induits ont été étudiés en détails pour mieux comprendre les mécanismes réactionnels et leur réversibilité. Les propriétés électrochimiques de couches minces de MgH2 et des poudres composites de MgH2+TiH2 ont été étudiées en utilisant à la fois des électrolytes organiques liquides et un électrolyte solide LiBH4. La capacité réversible et la tenue au cyclage dépendent fortement du rapport molaire entre les deux hydrures et des conditions de cyclage. Le transport de masse et la densité d’interfaces à l'intérieur de l'électrode sont identifiés comme les principaux facteurs affectant la réversibilité de la réaction de conversionToday, lithium-ion batteries are widely used as power supplies in portable electronics such as laptops, smartphones and cameras. However, new applications such as full electric vehicles and energy storage stationary systems require enhanced battery performances. In particular, novel electrode materials with higher energy density are needed.MgH2 and TiH2 hydrides and mixtures of them have high electrochemical capacity (> 1 Ah/g). They have been studied as negative electrode materials in Li-ion batteries. The conversion reaction of lithium with these hydrides and the related microstructural changes have been deeply investigated to gain a better understanding of reaction mechanisms and their reversibility. The electrochemical properties of MgH2 thin films and MgH2+TiH2 composite powders have been evaluated using both liquid organic and solid (LiBH4) electrolytes. Reversible capacity and cycle-life are found to strongly depend on both molar ratio between the hydrides and cycling conditions. Mass transport and density of interfaces within the electrode are identified as the main factors affecting the reversibility of the conversion reaction
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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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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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Martin, Andréa Joris Quentin. "Nano-sized Transition Metal Fluorides as Positive Electrode Materials for Alkali-Ion Batteries." Doctoral thesis, Humboldt-Universität zu Berlin, 2020. http://dx.doi.org/10.18452/21619.
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Übergangsmetallfluoridverbindungen sind sehr vielversprechende Kandidaten für die nächste Generation von Kathoden für Alkaliionenbatterien. Dennoch verhindern einige Nachteile dieser Materialklasse ihre Anwendung in Energiespeichermedien. Metallfluoride haben eine stark isolierende Wirkung, außerdem bewirken die Mechanismen beim Lade-/Entladevorgang, große Volumenänderungen und somit eine drastische Reorganisation des Materials, welche nur geringfügig umkehrbar ist. Um diese Nachteile zu reduzieren, werden in dieser Arbeit innovative Syntheserouten für die Umwandlung von Metallfluoridverbindungen sowie deren Anwendung in Alkaliionenbatterien vorgestellt. Im ersten Teil werden MFx Verbindungen (M = Co, Fe; x = 2 oder 3) untersucht. Diese Materialien zeigen eine hohe Ausgangskapazität aber nur bei sehr geringen C-Raten und zudem sehr geringe Zyklisierbarkeiten. Ex-situ-XRD und -TEM zeigen, dass die geringe Umkehrbarkeit der Prozesse hauptsächlich aus der Umwandlungsreaktion während des Be-/Entladens resultieren. Im zweiten Teil werden sowohl die Synthesen als auch die elektrochemischen Eigenschaften von Perowskiten aus Übergangsmetallfluoriden vorgestellt. NaFeF3 zeigt hierbei exzellente Leistungen und Reversibilitäten. Die Untersuchung der Mechansimen durch ex-situ und operando XRD während der Be- und Entladeprozesse hinsichtlich verschiedener Alkalisysteme zeigt, dass das kristalline Netzwerk über den Zyklus erhalten bleibt. Dies führt zur hohen Reversibilität und hohen Leistung selbst bei hohen C-Raten. Der Erhalt der Kristallstruktur wird durch elektrochemische Stabilisierung der kubischen Konformation von FeF3 ermöglicht, welche normalerweise erst bei hohen Temperaturen (400 °C) beobachtet wird und durch geringere Reorganisationen innerhalb des Kristallgerüsts erklärt werden kann. Ähnliche elektrochemische Eigenschaften können für KFeF3 und NH4FeF3 beobachtet werden, wobei erstmalig von Ammoniumionen als Ladungsträger in Alkaliionensystemen berichtet wird.Metal fluoride compounds appear as very appealing candidates for the next generation of alkali-ion battery cathodes. However, many drawbacks prevent this family of compounds to be applicable to storage systems. Metal fluorides demonstrate a high insulating character, and the mechanisms involved during the discharge/charge processes atom engender large volume changes and a drastic reorganization of the material, which induces poor reversibility. In order to answer these problematics, the present thesis reports the elaboration of innovative synthesis routes for transition metal fluoride compounds and the application of these fluoride materials in alkali-ion battery systems. In a first part, MFx compounds (M = Co, Fe; x = 2 or 3) are studied. Those compounds exhibit high initial capacity but very poor cyclability and low C-rate capabilities. Ex-situ X-ray diffraction and transmission electron microscopy demonstrate that the low reversibility of the processes is mainly due to the conversion reaction occurring during their discharge/charge. In the second part, the syntheses of transition metal fluoride perovskites are reported, as well as their electrochemical properties. NaFeF3 demonstrates excellent performances and reversibility. The study of the mechanisms occurring during its charge/discharge processes towards different alkali systems by ex-situ and operando X-ray diffraction reveals that its crystalline framework is maintained along the cycles, resulting in high reversibility and excellent C-rate performance. This retention of the crystal framework is possible by an electrochemical stabilization of a cubic conformation of FeF3, which is usually only observable at high temperature (400 °C), and can be explained by lower reorganizations within the crystal framework. Similar electrochemical properties could be observed for KFeF3 and NH4FeF3, where ammonium ions are reported for the first time as a charge carrier in alkali-ion systems.
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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 XAn 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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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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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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Arayamparambil, Jeethu Jiju. "Metal carbodiimides and cyanamides, a new family of electrode materials for Li-ion batteries." Thesis, Montpellier, 2019. http://www.theses.fr/2019MONTS066.
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Les batteries Li-ion constituent actuellement la technologie de choix pour tous les équipements portables, les moyens de transports électriques et le stockage stationnaire des énergies renouvelables. Actuellement, le graphite est incontestablement le matériau d'anode le plus utilisé pour les batteries Li-ion en raison de ses excellentes propriétés telles que sa durabilité, son abondance et son faible coût. Cependant, sa faible densité d'énergie est son talon d'Achille. En plus, le graphite présente certains problèmes de sécurité, en particulier à des puissances élevées. En conséquence, d’autres matériaux sûrs, économiques, à haute densité énergétique et à longue durée de vie, font l’objet d’importants travaux de recherche notamment des candidats comme le silicium et l’étain. Depuis 2015, la possibilité d'utiliser des carbodiimides de métaux de a été rapportée, et certains d'entre eux ont montré des performances électrochimiques prometteuses en tant que matériaux anodiques pour les batteries aux ions Li et Na. Comme tous les matériaux d'électrode à base de métaux divalents, les carbodiimides souffrent d'une capacité irréversible initiale et d'un potentiel de fonctionnement élevés, mais présentent une meilleure tenue en cyclage. L'application de carbodiimides de métaux de transition dans le domaine du stockage (et de la conversion) de l'énergie en est encore à ses débuts malgré les progrès réalisés en terme d'évaluation électrochimique. Il reste encore beaucoup à faire pour établir les mécanismes réactionnels qui régissent les performances prometteuses observées. Outre les carbodiimides de métaux de transition, il reste encore de nombreux carbodiimides inorganiques à explorer. Par conséquent, les principaux objectifs de cette thèse sont (i) d’évaluer la possibilité d’application de nouveaux carbodiimides comme matériaux d’électrode pour les batteries Li-ion et (ii) d’établir les mécanismes réactionnels électrochimique de ces matériaux au moyen de techniques de caractérisation operando avancées couplées à des calculs DFT. En ce qui concerne les performances électrochimiques, Cr2(NCN)3 s'est révélé être le meilleur matériau d'anode, avec une capacité spécifique stable de plus de 600 mAh.g-1 sur plus de 900 cycles à un régime de 2C. CoNCN et FeNCN ont également d’excellentes propriétés électrochimiques, car ils peuvent maintenir une capacité spécifique supérieure à 500 mAh.g-1 pendant plus de 100 cycles à un régime de 2C. Des performances plus modestes ont été observées pour PbNCN, Ag2NCN et ZnNCN car les capacités pratiques sont bien inférieures aux capacités théoriques. Ces phases montrent également une chute de la capacité sur les premiers 20 cycles. Ces trois catégories de performances sont bien corrélées avec les trois mécanismes différents réactionnels établis pour toutes les phases étudiées. Jusqu'à présent, trois types de mécanismes réactionnels ont été identifiés, à savoir (i) un processus combinant une étape d’intercalation suivie d’une étape de conversion dans le cas de Cr2(NCN)3, (ii) une réaction de conversion pure dans le cas de CoNCN et enfin (iii) un mécanisme combiné de conversion et d’alliage dans le cas des composés Pb, Zn et Ag. Il convient de noter que, quelle que soit le mécanisme réactionnel, tous les matériaux d'anode carbodiimide sont confrontés à la limitation d'une faible efficacité coulombique au cours des premiers cycles. Pour surmonter cet obstacle, il faut déployer plus d'efforts pour clarifier la nature et le rôle de la SEI dans la performance globale de cette famille de matériaux. Bien que les résultats prometteurs présentés dans ce travail ne répondent probablement pas aux normes requises pour intégrer les carbodiimides dans des applications commerciales, ils ont au moins le mérite de montrer la richesse de la chimie des carbodiimides et de stimuler davantage de travaux de recherche sur cette famille de matériaux inorganiques moléculaires relativement jeuneLi-ion batteries are currently the most common choice for all portable electronic devices but also for hybrid electric vehicles and renewable energy sectors. At present, graphite is routinely employed as the anode material for Li-ion-batteries due to its excellent attributes such as long cycle life, abundance, and relatively cost effective. However, the disadvantages of graphitic anode include low energy density and safety concerns. As a consequence, alternative cost effective anode materials with high energy density and long cycle life have been widely explored. Among this transition metal based compounds are an exciting and reasonable alternative for graphite owing to their high specific capacity. Compounds with the formula MX where M is a divalent metal and X = O, S, PO4, and CO3 have been reported to be electrochemically active at average voltages around 1 volts. In spite of their high theoretical specific capacities, high irreversible capacity in the first lithiation and the weak cycling life prevent the practical use of these materials. Since 2015, the possibility of using transition metal carbodiimides (MNCN, with M = Fe, Mn, Co, Cu, Zn, Ni) have been reported, and some of them have shown promising electrochemical performance as anode materials for both Li and Na ion batteries. Like all divalent metal based electrode materials, carbodiimides have been found to suffer from high initial irreversible capacity and high operating voltage, however they show a better cycle life. The application of transition metal carbodiimides in the field of energy storage (and conversion) is still in its early stages and despite progress in electrochemical evaluation much remains to be done in order to establish the reaction mechanisms that govern the reported promising performances. Besides the transition metal carbodiimides there are still many other inorganic cyanamides and carbodiimides materials to explore. Therefore the main targets of this PhD work are (i) to assess the properties of new carbodiimides/cyanamides as electrode materials for LiBs and (ii) to establish their electrochemical reaction mechanisms via advanced operando techniques and DFT calculations. Concerning the electrochemical performance, Cr2(NCN)3 turned out to be by the far the best carbodiimide anode material with stable specific capacity of more than 600 mAh.g-1 for more than 900 cycles at 2C rate. CoNCN and FeNCN have also shown excellent electrochemical properties since they can sustain a specific capacity higher than 500 mAh.g-1 for more than 100 cycles at 2C rate. Poor performance was observed for PbNCN, Ag2NCN and ZnNCN since the practical capacities are well below the theoretical ones. These phase show also fast capacity fading during the first 20 cycles. These three performance categories correlate well with the three different reaction mechanisms established for the investigated phases. Up to now, three types of reaction mechanism have been identified including (i) Combined intercalation and conversion processes in the case of Cr2(NCN)3 as evidenced by both theoretical and experimental methods, (ii) pure conversion reaction in the case of CoNCN and finally (iii) a combined conversion and alloying mechanism in the case of Pb, Zn and Ag compounds. It is worth noting that whatever the reaction pathway, all the carbodiimide/cyanamide anode materials face the limitation of a significantly low coulombic efficiency during the first cycles. To overcome this obstacle, much effort is needed to clarify the nature and the role of SEI in the overall performance of this family of materials. The promising results reported in this work do not probably yet meet the standards needed to take carbodiimides/cyanamides into the practical applications, but they clearly evidence the rich possibilities offered by this young family of molecular inorganic materials
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Thanaweera, Achchige Dumindu P. "Design and characterisation of layered transition metal oxide cathode materials for Na-ion batteries." Thesis, Queensland University of Technology, 2022. https://eprints.qut.edu.au/228445/1/Dumindu_Thanaweera%20Achchige_Thesis.pdf.
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Owing to the scarcity of lithium, discovering alternatives for lithium in rechargeable batteries is a critical requirement. Sodium is an ideal candidate for this purpose. The absence of exceptional cathode materials in sodium-ion batteries is a bottleneck in realizing the above objective. This study focused on synthesizing novel transition metal oxide cathode materials for sodium-ion batteries and improving their electrochemical properties. The outcomes of this study emphasized the importance of novel material compositions as well as the role of smart cation substitution, anion redox reaction, electrochemical activation and the effect of the combination of strategies in achieving next-generation high-capacity cathodes.
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LINGUA, GABRIELE. "Newly designed single-ion conducting polymer electrolytes enabling advanced Li-metal solid-state batteries." Doctoral thesis, Politecnico di Torino, 2022. http://hdl.handle.net/11583/2969103.
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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 travauxThe 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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Maisuradze, Mariam. "Synthesis and Characterization of Double Metal Hexacyanoferrates." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/21014/.
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Manganese Hexacyanoferrate (MnHCF) and nickel doped manganese hexacyanoferrate were synthesized by simple co-precipitation method. The water content and chemical formula was obtained by TGA and MP-AES measurements, functional groups by FT-IR analysis, the crystal structure by PXRD and a local geometry by XAS. Elemental species of cycled samples were further investigated by TXM and 2D XRF. Electrochemical tests were performed in the glass cell. With addition of nickel, vacancies and water content increased in the sample. Crystal structure changed from monoclinic to cubic. Ni disturbed the local structure of Mn, site, however, almost no change was observed in Fe site. After charge/discharge cycling of MnHCF intercalation was already found in the peripheries of charged species after 20 cycle in 2D XRF analysis and randomly distributed intercalated regions after 50 cycles in TXM analysis. Cyclic voltammetry showed that peak-to-peak separation is increasing in case of the addition of Ni to MnHCF.
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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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Sgarbi, Stabellini Francesca. "Synthesis and surface characterization of metal (Mn, Ti) hexacyanoferrate electrodes." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amslaurea.unibo.it/24378/.
Full textAbstract:
Due to the limited resources of lithium, new chemistries based on the abundant and cheap sodium and even zinc have been proposed for the battery market. Prussian Blue Analogues (PBAs) are a class of compounds which have been explored for many different applications because of their intriguing electrochemical and magnetic properties. Manganese and titanium hexacyanoferrate (MnHCF and TiHCF) belong to the class of PBAs. In this work, MnHCF and TiHCF electrodes were synthetized, cycled with cyclic voltammetry (CV) in different setups and subsequently, the surfaces were characterized with X-ray Photoelectron Spectroscopy (XPS). The setups chosen for CVs were coin cell with zinc aqueous solution for the MnHCF series, three-electrode cell and symmetric coin cell with sodium aqueous solution for the TiHCF series. The electrodes were treated with different number of cycles to evaluate the chemical changes and alterations in oxidation states during cycling.
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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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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.
Full textAbstract:
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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Mohamed, Zakiah. "Relationships Among Structure, Magnetism and State of Charge in Positive Electrode Materials for Metal-Ion Batteries." Thesis, The University of Sydney, 2015. http://hdl.handle.net/2123/14438.
Full textAbstract:
Polyanionic framework materials containing 3d transition metals such as iron, cobalt and manganese are attractive candidates as electrodes in lithium and sodium ion batteries due to their thermal stability, long cycle life and environmental friendliness. LiFePO4 is already used in some commercial lithium ion batteries as a positive electrode material where these are key attributes, but it still has lower energy density and higher costs compared to the more commonly used LiCoO2. This thesis describes a combined physical properties and magnetic structures some of these materials, aimed at improving our understanding of their solid-state chemistry, and ultimately their performance as battery materials by relating those physical and magnetic properties to the state of charge of the battery. A variety of polyanionic materials including phosphates, pyrophosphates and silicates were prepared using solid-state synthesis. All compounds were intensively characterized using specific heat capacity and magnetic measurements, X-ray, neutron and synchrotron X-ray diffraction techniques. Low-temperature neutron diffraction was used to solved and refined the magnetic structures. During the lithium extraction process, the magnetic properties can vary significantly because it involve redox reaction of transition metals. Measuring the magnetic properties of working electrode materials can therefore potentially provide information about local structural changes including the introduction of defects, decomposition and phase segregation. The magnetic properties of chemically delithiated samples were also studied so that they could be used as reference materials. In the first part of the thesis, the phosphates family AM1-xM′xPO4 (A = Li, Na; M = Mn, Fe; M′ = Zn, Mn, Fe) are intensively studied. These phosphates are modified in two ways: by doping with magnetic and non-magnetic transition metals. It was found that all compounds exhibit antiferromagnetic ordering at low temperatures, but the nature and ordering temperatures depend on doping. In the course of this work, the magnetic structures of two types of sodium phosphate were determined for the first time,triphylite and maricite NaFePO4. The triphylite type showed similar crystal and magnetic properties as LiFePO4, while the maricite type demonstrated a transition from commensurate (T < 12 K) to incommensurate (12 < T < 13 K) magnetic phases. A spin-flop transition in the commensurate phase was also observed. These results are discussed in the context of spin frustration on the Fe2+ sites. The second type of cathode material studied was the pyrophosphate A2M1-xM′xP2O7 (A = Li, Na; M = Fe; M′ = Co, Mn). Varying the compositions of these materials led to significant changes in crystallographic and electronic structure with remarkable effects on the magnetic properties and structures.The magnetic structures of Li2(Fe1-xCox)P2O7 and Na2(Fe1-xMnx)P2O7 solid solutions were explored in the course of this work. The crystal and magnetic structures of the silicates γ-Li2MnSiO4 and β-Li2CoSiO4 were investigated and their magnetic structures solved for the first time, including for chemically delithiated versions of Li2CoSiO4. Magnetic property measurements confirmed that Co had oxidised from Co2+ to Co3+, confirming that delithiation was successful while also serving to demonstrate the sensitivity of magnetic measurements to lithium content. In addition, the structural evolution of Li2CoSiO4 was tracked by in situ S-XRD and revealed no phase transformation during cycling. In summary, the outcome of this study is an extension of the state of knowledge of the low-temperature magnetic properties and structures of polyanion-based transition metal oxides, and a demonstration of the sensitivity of those properties and structures to electrochemical state. Further refinement of this approach could lead to a new tool for developing improved positive electrode materials for rechargeable batteries. The work also yielded crucial missing information concerning the electronic ground state of these materials, required for future high-level computational studies aimed at predicting properties including ionic conductivity.
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Cognet, Marine. "Elaboration de matériaux hybrides pour le stockage de l’énergie et le recyclage de batteries Li-Ion." Thesis, Montpellier, 2019. http://www.theses.fr/2019MONTS064.
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Le stockage de l’énergie est devenu un enjeu mondial et un défi majeur pour la transition énergétique. Il est, en effet, nécessaire de développer des matériaux de batteries plus efficaces et facilement recyclables pour un développement responsable de ces technologies.Dans le cadre de cette thèse, les MOFs ont été utilisés comme matériaux de batteries mais aussi comme outil pour le recyclage de batteries Li-ion. Trois différents modèles de matériaux ont ainsi été synthétisés, basés sur des groupements phosphonates, sulfonates ou encore carboxylates associés à différents métaux de transition (Fe, Co, Ni et Mn). Des performances électrochimiques intéressantes ont été obtenues et des analyses après leurs cyclages ont permis de mieux mettre en évidence les avantages des MOFs en tant que matériaux d’électrodes. Enfin, une méthode de recyclage a été développée par la précipitation sélective de métaux sous la forme de MOFs dans de vraies solutions de déchets de batteries Li-ion. La formation de matériaux à haute valeur ajoutée peut-être une des solutions pour fermer le cycle de vie des batteries Li-ion de façon économiqueEnergy storage is one of the biggest challenges for next decades and a key player for the energy transition. The management of renewable energy production requires more efficient and easily recyclable electrochemical energy storage devices for the eco-responsible development of those technologies.During this PhD thesis, MOFs were used as electrode material but also as a tool for recycling of Li-ion batteries. Three differents MOFs, based on phosphonate, sulfonate or carboxylate ligands, have been developed with different transition metals (Fe, Ni, Mn and Co). Promising electrochemical properties have been observed and post-cycling analysis allowed enlightening the advantages of MOFs as electrode materials. Finally, a recycling method have been developed by the selective precipitation of metals as MOFs in real Li-ion battery waste solutions. The formation of high valuable materials could be one way to close the life circle of batteries economically
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Vijayakumar, V. "Preparation, characterization and application of proton, lithium and zinc-ion conducting polymer electrolytes for supercapacitors, lithium- and zinc-metal batteries." Thesis(Ph.D.), CSIR-National Chemical Laboratory, 2021. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/5972.
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The use of liquid electrolytes in energy storage devices are associated with several constraints pertaining to safety. Polymer electrolytes are suitable candidates to overcome several problems associated with free-flowing liquid electrolytes. The current thesis deals with the development of proton, lithium, and zinc conducting gel polymer electrolytes for electrochemical energy storage devices such as supercapacitors, lithium-metal batteries, and zinc-metal batteries. Special emphasis is given to the improvement of electrode|electrolyte interface in polymer electrolyte-based energy storage devices by the ultraviolet-light-induced in situ processing strategy. Ultimately, the prospects of employing polymer electrolytes as an alternative to liquid electrolytes in energy storage devices is revisited in this dissertation through four dedicated working chapters.University Grants Commissions (UGC), India CSIR, India
AcSIR
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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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Martin, Andréa Joris Quentin [Verfasser]. "Nano-sized Transition Metal Fluorides as Positive Electrode Materials for Alkali-Ion Batteries / Andréa Joris Quentin Martin." Berlin : Humboldt-Universität zu Berlin, 2020. http://d-nb.info/1220690406/34.
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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.
Full textAbstract:
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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Inamoto, Jun-ichi, and 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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Zhao, Zijian [Verfasser], and H. [Akademischer Betreuer] Ehrenberg. "Study of Ternary Transition Metal Oxides as Conversion Anodes in Li-Ion Batteries / Zijian Zhao ; Betreuer: H. Ehrenberg." Karlsruhe : KIT-Bibliothek, 2019. http://d-nb.info/1199459917/34.
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Baur, Christian [Verfasser]. "Li-rich disordered rock salt transition metal oxyfluorides as novel cathode materials in lithium-ion batteries / Christian Baur." Ulm : Universität Ulm, 2020. http://d-nb.info/1219577693/34.
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Gosselink, Denise. "Study of Transition Metal Phosphides as Anode Materials for Lithium-ion Batteries: Phase Transitions and the Role of the Anionic Network." Thesis, University of Waterloo, 2006. http://hdl.handle.net/10012/2958.
Full textAbstract:
This study highlights the importance of the anion in the electrochemical uptake of lithium by metal phosphides. It is shown through a variety of in-situ and ex-situ analytical techniques that the redox active centers in three different systems (MnP4, FeP2, and CoP3) are not necessarily cationic but can rest almost entirely upon the anionic network, thanks to the high degree of covalency of the metal-phosphorus bond and strong P-character of the uppermost filled electronic bands in the phosphides. The electrochemical mechanism responsible for reversible Li uptake depends on the transition metal, whether a lithiated ternary phase exists in the phase diagram with the same M:P stoichiometry as the binary phase, and on the structure of the starting phase. When both binary and lithiated ternary phases of the transition metal exist, as in the case of MnP4 and Li7MnP4, a semi-topotactic phase transformation between binary and ternary phases occurs upon lithium uptake and removal. When only the binary phase exists two different behaviours are observed. In the FeP2 system, lithium uptake leads to the formation of an amorphous material in which short-range order persists; removal of lithium reforms some the long-range order bonds. In the case of CoP3, lithium uptake results in phase decomposition to metallic cobalt plus lithium triphosphide, which becomes the active material for the subsequent cycles.
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Tian, Guiying [Verfasser], and 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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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.
Full textAbstract:
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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聖, 橋上, and Satoshi Hashigami. "Studies on degradation factors and their mitigation methods of cathode materials for advanced lithium-ion batteries." Thesis, https://doors.doshisha.ac.jp/opac/opac_link/bibid/BB13106330/?lang=0, 2019. https://doors.doshisha.ac.jp/opac/opac_link/bibid/BB13106330/?lang=0.
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再生可能エネルギーの大量導入に向けて、電力需給の安定化を目的として蓄電池を用いる電力貯蔵技術に注目が集まっている。現状のリチウムイオン電池(LIB)がベースの先進LIBは250Wh/kgの高エネルギー密度を有し、自動車のみならず電力貯蔵用途としても普及が期待されている。本研究では先進LIB正極材料として期待されるリチウム過剰系正極と高ニッケル三元系正極について容量低下などの劣化要因を明確にして、それら課題に対して正極粒子への酸化物修飾による解決を検討した。The development of energy storage technologies using batteries has attracted much attention to introduce the renewable energy. If we can achieve 250 Wh kg-1 with the advanced LIBs based on the principle of LIB, we can lower the cost of the total energy storage systems while ensuring the safety, and hence the advanced LIBs will accelerate the world-wide spread of large-scale power storage systems. In this thesis, the author focused surface modification of lithium-rich layered ternary transition metal oxide and high-nickel layered ternary transition metal oxide cathode particles with oxides as mitigation methods for capacity fading.
博士(工学)
Doctor of Philosophy in Engineering
同志社大学
Doshisha University
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Combelles, Cécil. "Modélisation ab-initio Appliquée à la Conception de Nouvelles Batteries Li-Ion." Phd thesis, Université Montpellier II - Sciences et Techniques du Languedoc, 2009. http://tel.archives-ouvertes.fr/tel-00421182.
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Pour améliorer les performances des batteries au lithium, des ruptures technologiques sont nécessaires. Ceci impose que les aspects fondamentaux liés au fonctionnement de ces dispositifs électroniques soient reconsidérés. Dans cette optique, les méthodes de la chimie quantique peuvent apporter une aide précieuse, notamment pour comprendre les phénomènes électroniques microscopiques, à l'origine du stockage de l'énergie. Établir une relation directe entre la nature de la liaison chimique (microscopique) et les propriétés physico-chimiques (macroscopiques) des matériaux d'électrode pour batteries Li-Ion est donc l'objectif dans lequel s'inscrivent les travaux exposés dans cette thèse. Ce travail explore à la fois des aspects méthodologiques et des applications. Il vise à proposer des méthodologies d'analyse simples permettant de traiter les réactions électrochimiques d'un point de vue théorique et de déterminer les mécanismes microscopiques mis en jeu au cours des cycles de charge et de décharge des batteries. Les systèmes étudiés sont les composés d'insertion du graphite (Li-GICs) et un matériau hybride de type MOFs (« Metal Organic Framework ») basé sur l'ion ferrique (MIL-53(Fe)). Pour les Li-GICs, une nouvelle méthode couplant des calculs premiers principes DFT à un modèle statistique dérivé du modèle de Bethe-Peierls a été développée pour rendre compte des effets d'entropie (de configuration) dans leur diagramme de phase. Les résultats obtenus apportent un nouveau regard sur les processus électrochimiques induits par le lithium, ouvrant des perspectives technologiques intéressantes pour remédier aux problèmes de sécurité posés par ce type d'électrode. Pour le MIL-53(Fe), la méthode DFT+U a été utilisée pour rendre compte des effets de corrélation électronique et pour reproduire l'état fondamental complexe de ce système. Les résultats obtenus ont permis de comprendre l'origine de la faible capacité de ce matériau vis-`a-vis du lithium.
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Li, Chengping [Verfasser], and H. [Akademischer Betreuer] Ehrenberg. "Investigation of Metal Oxides/Sulfides as Negative Electrode Materials for Li-ion and Beyond-Li Batteries / Chengping Li ; Betreuer: H. Ehrenberg." Karlsruhe : KIT-Bibliothek, 2021. http://d-nb.info/1227451296/34.
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De, Villiers Daniel. "The application of new generation batteries in old tactical radios / D. de Villiers." Thesis, North-West University, 2007. http://hdl.handle.net/10394/738.
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The power requirement for the soldier's equipment is largely supplied by batteries.
Situational awareness is critical for a soldier to perform his tasks. Therefore the radio used
by the soldier is a key element in situational awareness and also consumes the most power.
The South African National Defence Force (SANDF) uses the A43 tactical radio specifically
designed for them. The radios are regarded as old technology but will be in use for about
another five years.
The radios still use non-rechargeable alkaline batteries which do not last very long and are
not cost effective. The purpose of this study is to research the new generation secondary
batteries as a possible replacement for the alkaline battery packs. The new generation
batteries investigated in this study are the latest rechargeable batteries, also called
secondary batteries. They include nickel cadmium, nickel metal hydride, lithium ion,
rechargeable alkaline manganese and zinc air.
The main features of rechargeable cells are covered and the cell characteristics are defined
to allow the technology to be matched to the user requirement. Li-ion technology was found
to be the best choice. This research also showed that international trends in battery usage
are towards Li-ion. A new Li-ion battery was designed based on commercial cells. Tests
showed that commercial Li-ion cells can be used in the radio and that they outperform the
current battery by far.
The study also examined the design of a New Generation Battery System consisting of an
intelligent battery, a charger which uses a Systems Management Bus and a battery 'state of
health" analyser to assist the user to maintain the batteries. Tests were done to demonstrate
that the battery can withstand typical military environmental conditions. Expected military
missions for a battery system were defined and used to compare the cost between the
existing batteries and the new batteries system. Important usage factors which will influence
the client when using a New Generation Battery System were addressed.
To summarise, this study showed that by using a New Generation Battery System, the
SANDF could relieve the operational cost of the A43 radio while saving on weight and
enabling the soldier to carry out longer missions.Thesis (M.Ing. (Electronical Engineering))--North-West University, Potchefstroom Campus, 2008.
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Lyness, Christopher. "Novel lithium-ion host materials for electrode applications." Thesis, University of St Andrews, 2011. http://hdl.handle.net/10023/1921.
Full textAbstract:
Two novel lithium host materials were investigated using structural and electrochemical analysis; the cathode material Li₂CoSiO₄ and the LiMO₂ class of anodes (where M is a transition metal ion). Li₂CoSiO₄ materials were produced utilising a combination of solid state and hydrothermal synthesis conditions. Three Li₂CoSiO₄ polymorphs were synthesised; β[subscript(I)], β[subscript(II)] and γ₀. The Li₂CoSiO₄ polymorphs formed structures based around a distorted Li₃PO₄ structure. The β[subscript(II)] material was indexed to a Pmn2₁ space group, the β[subscript(I)] polymorph to Pbn2₁ and the γ₀ material was indexed to the P2₁/n space group. A varying degree of cation mixing between lithium and cobalt sites was observed across the polymorphs. The β[subscript(II)] polymorph produced 210mAh/g of capacity on first charge, with a first discharge capacity of 67mAh/g. It was found that the β[subscript(I)] material converted to the β[subscript(II)] polymorph during first charge. The γ₀ polymorph showed almost negligible electrochemical performance. Capacity retention of all polymorphs was poor, diminishing significantly by the tenth cycle. The effect of mechanical milling and carbon coating upon β[subscript(II)], β[subscript(I)] and γ₀ materials was also investigated. Various Li[subscript(1+x)]V[subscript(1-x)]O₂ materials (where 0≤X≤0.2) were produced through solid state synthesis. LiVO₂ was found to convert to Li₂VO₂ on discharge, this process was found to be strongly dependent on the amount of excess lithium in the system. The Li₁.₀₈V₀.₉₂O₂ material had the highest first discharge capacity at 310mAh/g. It was found that the initial discharge consisted of several distinct electrochemical processes, connected by a complicated relationship, with significant irreversible capacity on first discharge. Several other LiMO₂ systems were investigated for their ability to convert to layered Li₂MO₂ structures on low voltage discharge. While LiCoO₂ failed to convert to a Li₂CoO₂ structure, LiMn₀.₅Ni₀.₅O₂ underwent an addition type reaction to form Li₂Mn₀.₅Ni₀.₅O₂. A previously unknown Li₂Ni[subscript(X)]Co[subscript(1-X)]O₂ structure was observed, identified during the discharge of LiNi₀.₃₃Co₀.₆₆O₂.
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Liu, Xinye. "Binary metal organic framework derived hierarchical hollow Ni3S2/Co9S8/N-doped carbon composite with superior sodium storage performance." University of Akron / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron1489784678856585.
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MANCINI, Marilena. "Improved anodic materials for lithium-ion batteries: surface modification by metal deposition and electrochemical characterization of oxidized graphite and titanium dioxide electrodes." Doctoral thesis, Università degli Studi di Camerino, 2009. http://hdl.handle.net/11581/401752.
Full textAbstract:
The research work presented in this thesis has been carried out during my Ph.D. study at the Chemistry Department of Camerino University (Italy) and at the ''Centre for Solar Energy and Hydrogen Research Baden-Wa'¼rttemberg'' (ZSW) in Ulm, (Germany). [...] The thesis deals with the evaluation of the electrochemical performances of metal-modified anodes for lithium-ion batteries. The results obtained by using either partially oxidized graphite or TiO2 anatase as active materials for anode fabrication are presented. The obtained results have been the subject of the following scientific publications and proceedings of congress: F. Nobili, S. Dsoke, M. Mancini, R. Tossici, R. Marassi, ''Electrochemical investigation of polarization phenomena and intercalation kinetics of oxidized graphite electrodes coated with evaporated metal layers'', Journal of Power Sources, 180 (2008) 845-851. M. Mancini, F. Nobili, S. Dsoke, F. D'Amico, R. Tossici, F. Croce, R. Marassi, ''Lithium intercalation, interfacial kinetics of composite anodes formed by oxidized graphite and copper'', Journal of Power Sources (2008), in Press, doi:10.1016/j.jpowsour.2008.10.084. M. Mancini, P. Kubiak, J. Geserick, R. Marassi, N. Ha'¼sing, M. Wohlfahrt-Mehrens, ''Mesoporous anatase TiO2 composite electrodes: electrochemical characterization and high rate performances'', Journal of Power Sources (2008), in Press, doi:10.1016/j.jpowsour.2008.10.050. F. Nobili, S. Dsoke, M. Mancini, R. Marassi, ''Interfacial properties of copper coated graphite electrodes: coating thickness dependence'', Fuel Cells, Accepted, DOI: 10.1002/fuce.200800087. M. Mancini, P. Kubiak, J. Geserick, R. Marassi, N. Ha'¼sing, M. Wohlfahrt-Mehrens, ''Electrochemical performances of mesoporous anatase TiO2 electrodes modified by vacuum metal deposition'', 214th Meeting of the Electrochemical Society (ECS). Honolulu, Hawaii, USA, 12-17 October, 2008. Abs. 1261. P. Kubiak, M. Mancini, J. Geserick, R. Marassi, N. Ha'¼sing and M. Wohlfahrt-Mehrens, ''Mesoporous anatase TiO2 composite electrodes: electrochemical characterization and high rate performances'', IMLB-14, The 14th International Meeting on Lithium Batteries. TEDA, Tianjin, China, 22-28 June, 2008. Abs. 142. M. Mancini, F. Nobili, S. Dsoke, R. Tossici, R. Marassi, ''Metal coated oxidized graphite electrodes: electrochemical investigation of polarization phenomena and intercalation kinetics'', 11th UECT Ulm Electrochemical Talks 2008. Neu-Ulm, Germany, 10-12 June, 2008. Abs. p. 48. F. Nobili, S. Dsoke, M. Mancini, R. Tossici, R. Marassi, ''Electrochemical investigation of polarization phenomena and intercalation kinetics of oxidized graphite electrodes coated with evaporated metal layers'', 3rd German-Italian-Japanese Meeting of Electrochemists. Taormina-Messina, Italy, May 25-28, 2008. Abs p.s 41-42. M. Mancini, S. Dsoke, F. Nobili, R. Tossici, R. Marassi, ''Metal-oxidized graphite composite electrodes as anodes for lithium-ion batteries'', School of the Physical Chemistry Section: ''Composite Materials: from Molecular Sciences to nanotechnology''. Turin, Italy, 3-8 September, 2006. Abs. p. 94.
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Giesecke, Marianne. "Characterizing ions in solution by NMR methods." Doctoral thesis, KTH, Tillämpad fysikalisk kemi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-149552.
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NMR experiments performed under the effect of electric fields, either continuous or pulsed, can provide quantitative parameters related to ion association and ion transport in solution. Electrophoretic NMR (eNMR) is based on a diffusion pulse-sequence with electric fields applied in the form of pulses. Magnetic field gradients enable the measurement of the electrophoretic mobility of charged species, a parameter that can be related to ionic association. The effective charge of the tetramethylammonium cation ion in water, dimethylsulphoxide (DMSO), acetonitrile, methanol and ethanol was estimated by eNMR and diffusion measurements and compared to the value predicted by the Debye-Hückel-Onsager limiting law. The difference between the predicted and measured effective charge was attributed to ion pairing which was found to be especially significant in ethanol. The association of a large set of cations to polyethylene oxide (PEO) in methanol, through the ion-dipole interaction, was quantified by eNMR. The trends found were in good agreement with the scarce data from other methods. Significant association was found for cations that have a surface charge density below a critical value. For short PEO chains, the charge per monomer was found to be significantly higher than for longer PEO chains when binding to the same cations. This was attributed to the high entropy cost required to rearrange a long chain in order to optimize the ion-dipole interactions with the cations. Moreover, it was suggested that short PEO chains may exhibit distinct binding modes in the presence of different cations, as supported by diffusion measurements, relaxation measurements and chemical shift data. The protonation state of a uranium (VI)-adenosine monophosphate (AMP) complex in aqueous solution was measured by eNMR in the alkaline pH range. The question whether or not specific oxygens in the ligand were protonated was resolved by considering the possible association of other species present in the solution to the complex. The methodology of eNMR was developed through the introduction of a new pulse-sequence which suppresses artifactual flow effects in highly conductive samples. In another experimental setup, using NMR imaging, a constant current was applied to a lithium ion (Li ion) battery model. Here, 7Li spin-echo imaging was used to probe the spin density in the electrolyte and thus visualize the development of Li+ concentration gradients. The Li+ transport number and salt diffusivity were obtained within an electrochemical transport model. The parameters obtained were in good agreement with data for similar electrolytes. The use of an alternative imaging method based on CTI (Constant Time Imaging) was explored and implemented.QC 20140825
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Zhang, Yirui S. M. Massachusetts Institute of Technology. "Understanding the pathway and mechanism of electrolyte decomposition on metal oxide surfaces in Li-ion batteries by in situ Fourier Transform Infrared Spectroscopy." Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/122227.
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Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019Cataloged from PDF version of thesis.
Includes bibliographical references (pages 69-75).
Understanding (electro)chemical reactions at the electrode-electrolyte interface (EEI) is crucial to promote the cycle life of lithium-ion batteries. In situ studies of EEI can provide new insights into reaction intermediates and soluble species not accessible by ex situ characterization of electrode surfaces. In this study, we developed an in situ Fourier Transform infrared spectroscopy (FTIR) method to investigate the (electro)chemical reactions at the interface between the electrolyte and composite positive electrode surface during charging. While ethyl methyl carbonate (EMC) and ethylene carbonate (EC) were stable against (electro)chemical oxidation on Pt up to 4.8 VL, dehydrogenation of both carbonates on the surface of LiNio.8Cooa.Mno.l02 (NMC81 1) electrodes was revealed by in situ FTIR spectra and density functional theory (DFT). Both solvents can dehydrogenate and form de-H EC and de-H EMC, respectively, with carbon atom binding to lattice oxygen and sticking on surface. De-H EC can further remove another hydrogen atom to form vinylene carbonate (VC) or bind together to form oligomers, both of which are soluble and hard to be accessed through ex-situ methods. In situ FTIR method successfully tracked detailed pathways of solvent decomposition on oxide surface, and electrochemical impedance spectroscopy (EIS) further confirmed the formation of a passivating layer from solvent decomposition on the surface. The impedance growth is oxide and solvation structure-dependent and it accounts for battery degrading. We finally proposed and verified multiple strategies to further improve the cycling stability of high-energy density positive electrode in Li-ion batteries.
by Yirui Zhang.
S.M.
S.M. Massachusetts Institute of Technology, Department of Mechanical Engineering
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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.
Full textAbstract:
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.
Full textAbstract:
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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Gao, Suning [Verfasser], Rudolf [Gutachter] Holze, Rudolf [Akademischer Betreuer] Holze, and 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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Bani, Hashemi Amir [Verfasser], Mantia Fabio [Akademischer Betreuer] La, Mantia Fabio [Gutachter] La, and Mauro [Gutachter] Pasta. "Electrochemical and morphological characterization of the Interface at negative electrodes in aqueous metal-ion batteries "Gas Evolution & electrodepostion Efficiency" / Amir Bani Hashemi ; Gutachter: Fabio La Mantia, Mauro Pasta ; Betreuer: Fabio La Mantia." Bremen : Staats- und Universitätsbibliothek Bremen, 2018. http://d-nb.info/1154925978/34.
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Bhatti, Asif Iqbal. "Calculs ab-initio et simulations atomistiques des propriétés thermodynamiques et cinétiques de complexes de métaux de transition utilisés comme batteries." Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAI092/document.
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Ce travail théorique vise à étudier, via les méthodes Premiers Principes, les propriétés des complexes de métaux de transitions, left[Mleft(dmbpyright)_{3}right]^{n+}nCi^{-} pour un usage en batterie. Pour cette étude ab-initio, les composés mono et bi-nucléaires ont été retenus. La pertinance de notre modélisation a été validée sur les composés mononucléaires. Nous nous sommes interessé au complexes de Fe, Ru et Cu pour lesquels une validation expérimentale était possible. Notre étude a principalement consisté à faire varier les degrés de liberté que nous possédons pour optimiser le voltage et la cinétique de chargement des batteries. Pour cela, nous avons fait varier le TM = Fe, Ru, et Cu, la nature des contre-ions Ci^{-}=PF_{6}^{-}, TFSI^{-} et ClO_{4}^{-} en interaction avec le polymère lors du processus de charge, ainsi que la longeur de la chaîne alkyl qui sépare les deux monomers dans le cas des composés binucléaires. Le composé à base de Fe avec une chaîne -left(CH_{2}right)_{n=6}- a été retenu comme le meilleur candidat pour une application batterie. Le composé à base Ru montre un comportement proche de celui du Fe, quant-au complexe de Cu, il présente des changements de géométrie locale sous chargement trop importants, le rendant peu apte à conduire à une cinétique efficace. Cette étude nous a permis de déterminer que l'approximation PBE était le meilleur choix possible pour modéliser nos complexes dans les conditions de fonctionnement en batterie (dans le champ créé par les contre-ions) et que l'approximation PBE0, généralement utilisée dans la littérature, ne pouvait rendre compte de la physico-chimie de nos composés dans de telles conditions.De surcroît, nous avons dévelopé pour le complexe de Fe, un potentiel atomistique de type “Champ de forces” de manière à pouvoir aborder les aspects dynamiques impliquant de plus grandes tailles de boîte de simulation. Ici, nous modélisons une structure 3D, totalement réticulée à partir de nos monomères à base de Fe. Nous nous sommes servi de la base de donnés DFT que nous avions généré (énergies, géométries, état de spin et fréquences vibrationnelles calculées) pour ajuster les paramètres entrant dans l'écriture du modèle. La construction de la géométrie initiale du polymère 3D a nécessité l'écriture d'un code de calcul visant à produire un arrangement complétement réticulé et à assigner les charges effectives issues des calculs DFT. Ce modèle nous a permis de déterminer les coefficients de diffusion des contre-ions pour les états totalement chargé et non-chargé. Un calcul plus ambitieux vise à déterminer les chemins de diffusion des contre-ions lors d'un processus de chargement en considérant un seul centre de degré d'oxydation 3+ au centre du polymère 3D, pour lequel les centres actifs possèdent un degré d'oxidation 2+. Les contre-ions assurent la neutralité globale.Keyword: Polymer, Electrochemistry, Li-ion Battery, DFT, Force Field development, 3D structure, Atomistic modelingAbstract Standard redox potentials for mono and bi-nuclear transition metal (TM) complexes left[Mleft(dmbpyright)_{3}right]^{n+}nCi^{-}, have been investigated using First Principles Calculation. Three metal centers are investigated: Fe, Ru, and Cu. Our modeling is validated on mono-nuclear compounds. This approach consists in determining the best small polymer (bi-nuclear) made out of these monomers for a battery application. For that, we varied the three available degrees of freedom i.e., the nature of the central TM atom (Fe, Ru, and Cu), counter-ions Ci=PF_{6}^{-}, TFSI^{-} and ClO_{4}^{-} in interaction with the polymer, and the alkyl chain -left(CH_{2}right)_{n}- of length n that connects both mono-nuclear in the bi-nuclear compound. The Iron compound with -left(CH_{2}right)_{n=6}- is found to be the best candidate. The left[Culeft(dmbpyright)_{2}right]^{n+}nCi^{-} complex shows too much structure deformation upon loading, making it less reliable for cathode material. Moreover, we studied two XC functional, PBE and PBE0 and found, for three complexes PBE approximation retains the ligand field picture whereas PBE0 functional induces an exaggerated and unexpected band dispersion by dissolving the ligand field picture expected for the octahedral environment of the TM in the studied complexes. These findings validate that hybrid functional for which it was designed to localize and cancel self-interaction error does not work for all system. More particularly, the PBE0 approximation fails to model the three complexes (Fe, Ru, and Cu) in functional conditions (in the field made by the counter-ions).Abstract Further, we have developed an atomistic potential relying on the Force Field scheme for the Iron complex in order to study the dynamical properties of this compound at larger simulation scale (3D reticulated polymerization made of our Fe complex monomers). We made an intensive use of our DFT data (energies, geometries, spin-state configurations and calculated vibrational properties) to develop the required parameters entering the model. Moreover, computational techniques (written python language) were developed specifically to create a 3D structure of transition metal complexes satisfying the condition to be fully reticulated. Bounding conditions had to be designed and a procedure aiming at fixing reliable and physical effective charges on each atom of the simulation cell (compatible with DFT results) were developed. Our first simulations have been attached to calculate the diffusion coefficients of the counter-ions in both the fully loaded and unloaded states. A more ambitious and realistic calculation aims at investigating the paths of the counter-ions when one single center starts to be loaded in an unloaded environment.Abstract Keyword: Polymer, Electrochemistry, Li-ion Battery, DFT, Force Field development, 3D structure, Atomistic modeling
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Adam, Robert. "Phasenumwandlungen und Änderungen der Mikrostruktur in Konversionselektroden für Lithium-Ionen-Batterien basierend auf 3d-Übergangsmetalloxiden." TU Bergakademie Freiberg, 2020. https://tubaf.qucosa.de/id/qucosa%3A75540.
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Die untersuchten Ausgangsmaterialien α-Fe2U3, ɣ-Fe2O3, Fe3O4, CoO, Co3O4, NiO sowie CuO eignen sich durch ihre hohe theoretische spezifische Kapazität als Elektrodenmaterial für Lithium-Ionen-Batterien. Die zugrundeliegenden Mechanismen zur Speicherung der Li-Ionen konnten mit allen Phasenumwandlungen und der Bildung von Zwischenprodukten im ersten Reduktionsschritt beschrieben werden. In Abhängigkeit von der Kristallstruktur der Ausgangsmaterialien und den Reaktionsgeschwindigkeiten konnten der Gesamtreaktion die einzelnen Mechanismen Interkalation von Li-Ionen, Substitution von Kationen in der Kristallstruktur und Konversionsmechanismus zugeordnet werden. Auf Grund des gemeinsamen kubisch flächenzentrierten Sauerstoffuntergitters der Ausgangsmaterialien und Zwischenprodukte zeigen sich für die Materialsysteme Fe-O, Co-O und Ni-O Orientierungsbeziehungen zwischen den Kristalliten des Ausgangsoxids, des lithiierten Metalloxids und der Li2O-Matrix. Im Gegensatz dazu sind die auf der CuO-Phase basierenden Kristallite regellos orientiert und zeigen eine höhere Zyklenstabilität. Die Orientierungsbeziehung zwischen den lithiierten Metalloxiden und der Li2O-Matrix hindert dagegen den Austausch der Li-Ionen, beeinträchtigt die Zyklenstabilität und trägt so zu einer schnelleren Alterung der Elektrode bei.
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Venkatesha, Akshatha. "Structural and Electrochemical Investigations of Monovalent and Divalent Aqueous Rechargeable Batteries." Thesis, 2023. https://etd.iisc.ac.in/handle/2005/6205.
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Several stringent laws and regulations have been enforced by various National/International agencies for the adoption of sustainable methods for energy production and usage. In recent times, electric grids based on alternative renewable sources such as solar, tidal, geothermal, and biomass have witnessed an upsurge. However, the intermittent nature of renewable resources and the sub-optimal electricity distribution/transmission calls for corrective measures leading to enhancement in the efficiency of electricity utilization. It is now widely recognized that energy storage via rechargeable batteries can be an efficient strategy in making the process(es) of electricity production and utilization from the grid to the end-user. Lithium-ion batteries are considered one of the most promising candidates with their outreach in various sectors, such as portable electronics, electric mobility, and grid storage applications. While advanced LiBs may offer good power and energy density, these are unlikely to meet the stiff scale-up targets concerning performance, cost, and safety in large-scale applications such as electric vehicles and the grid. Lithium reserves are limited and distributed heterogeneously. Additionally, conventional Li-ion uses expensive and flammable organic liquid electrolytes Aqueous rechargeable batteries (both monovalent and multivalent) are considered safer alternatives to state-of-the-art LIB technology and other non-aqueous battery chemistries owing to several advantages based on higher safety, cost-effectiveness, and higher ionic conductivity. As water is the solvent, aqueous rechargeable batteries do not require a sophisticated cell assembly line. One of the significant challenges that hinder their wide-scale application is the choice of suitable electrode materials that can work in the aqueous environment. In this thesis, various electrode materials with optimized electrolyte compositions for both aqueous monovalent and multivalent metal-ion rechargeable batteries have been explored. Chapter 3 explores the aqueous rechargeable mixed ion batteries we have developed using a NASICON anode and an olivine cathode in mixed ion electrolytes. The interesting phenomenon of selective ion insertion by the host structure in the presence of more than one cation in the electrolyte is probed in detail. In Chapters 4 to 7, we have explored various host materials (redox-active 2-D covalent organic frameworks, transition metal oxides, Prussian blue analogs) for the aqueous rechargeable divalent metal ion batteries (Zn, Ca, and Mg). The electrochemical characterizations of the materials are performed in detail to account for their redox behavior. The effect of electrolyte composition on the electrochemical performance of the cell is studied in detail. The thesis also probes the underlying mechanism of the battery operation associated with the structural/phase evolution of the electrode structure (with successive cycling) in detail with the help of various post-cycling ex-situ measurements.UGC, DST