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First-Principles Study of Advanced Cathode Materials and Cathode Coatings for Li-ion Battery
Başlık:
First-Principles Study of Advanced Cathode Materials and Cathode Coatings for Li-ion Battery
Yazar:
Lu, Zhi, author.
ISBN:
9780438115880
Yazar Ek Girişi:
Fiziksel Tanımlama:
1 electronic resource (211 pages)
Genel Not:
Source: Dissertation Abstracts International, Volume: 79-11(E), Section: B.
Advisors: Christopher M. Wolverton Committee members: Scott A. Barnett; Harold H. Kung; Monica Olvera de la Cruz.
Özet:
One of the challenges for improving the performance of Li-ion batteries to meet the increasing requirements for energy storage is the development of suitable cathode systems with larger capacity and better cycling performance. Designing advanced cathode materials and functional cathode coatings are two primary approaches to enhance the cathode performance currently. In this dissertation, various combinations of Density Functional Theory (DFT) calculations and analytical tools are utilized to investigate advanced cathode materials and functional cathode coatings from both thermodynamic and kinetic aspects. We first study the phase stability and structural evolution of novel high-capacity Li-rich layered cathode materials. We show that phase separation is energetically preferred relative to a solid solution at T = 0K, and the coherency stain energy has little influence on phase stability. We investigate the delithiation process of Li2--xMnO3 (one critical component in Li-rich layered cathode) as a function of Li content. The structural transition from O3 to O1-type stacking sequence and oxygen release with Li extraction is predicted. Mn migration from Mn layer to Li layer is favorable both thermodynamically and kinetically in the delithiated O3 structure. This work helps to understand the structural discrepancy, capacity loss and voltage fade during cycling in Li-rich layered cathode materials. Beyond Li-rich layered cathodes, we systematically study the thermodynamics of ordering and phase separation in the ternary layered Li[NiCoMn]O2 system and quaternary spinel [LiVac][MnNi] 2O4 system, which are the promising systems for advanced core-shell cathodes. In the layered Li[NiCoMn]O2 system, we construct binary and ternary phase diagrams as a function of temperature. In the quaternary spinel [LiVac][MnNi]2O4 system, we calculate quaternary phase diagrams as a function of temperature as well as voltage profiles of single ordered phases and multiphase composite structures. The computational strategy for multinary phase diagrams provides a pathway to understand and design novel core-shell battery cathode materials. At last, we focus on the study of functional cathode coatings for Li-ion battery. The poor cycling performance observed in many systems are mainly caused by side reactions occurring at the electrode/electrolyte interface. To identify functional coatings that can suppress this degradation, we present a high-throughput DFT based framework which consists of reaction models that describe thermodynamic and electrochemical stabilities, and acid-scavenging capabilities of materials. The screen successfully produces known effective coating materials (e.g., Al2O3 and MgO), and promising coating materials, such as trivalent oxides of d-block transition metals Sc, Ti, V, Cr, Mn and Y, are predicted. Beyond thermodynamics, we further build our framework by concentrating on the Li transport kinetics through a number of various metal oxides and fluorides in both crystalline and amorphous forms. Compared with typical solid-state materials used or formed in Li-ion batteries, several metal oxides display low Li diffusion barrier in both crystalline and amorphous forms, such as Y2O3, Sc2O3, ZnO and Ga2O3. This work is part of the framework for understanding the battery performance improvement systematically study the thermodynamics of ordering and phase separation in the ternary layered Li[NiCoMn]O2 system and quaternary spinel [LiVac][MnNi]2O4 system, which are the promising systems for advanced core-shell cathodes. In the layered Li[NiCoMn]O 2 system, we construct binary and ternary phase diagrams as a function of temperature. In the quaternary spinel [LiVac][MnNi]2O4 system, we calculate quaternary phase diagrams as a function of temperature as well as voltage profiles of single ordered phases and multiphase composite structures. The computational strategy for multinary phase diagrams provides a pathway to understand and design novel core-shell battery cathode materials. At last, we focus on the study of functional cathode coatings for Li-ion battery. The poor cycling performance observed in many systems are mainly caused by side reactions occurring at the electrode/electrolyte interface. To identify functional coatings that can suppress this degradation, we present a high-throughput DFT based framework which consists of reaction models that describe thermodynamic and electrochemical stabilities, and acid-scavenging capabilities of materials. The screen successfully produces known effective coating materials (e.g., Al2O3 and MgO), and promising coating materials, such as trivalent oxides of d-block transition metals Sc, Ti, V, Cr, Mn and Y, are predicted. Beyond thermodynamics, we further build our framework by concentrating on the Li transport kinetics through a number of various metal oxides and fluorides in both crystalline and amorphous forms. Compared with typical solid-state materials used or formed in Li-ion batteries, several metal oxides display low Li diffusion barrier in both crystalline and amorphous forms, such as Y2O3, Sc2O3, ZnO and Ga2 O3. (Abstract shortened by ProQuest.).
Notlar:
School code: 0163
Tüzel Kişi Ek Girişi:
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Yer Numarası | Demirbaş Numarası | Shelf Location | Lokasyon / Statüsü / İade Tarihi |
---|---|---|---|
XX(688110.1) | 688110-1001 | Proquest E-Tez Koleksiyonu | Arıyor... |
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