Li-Ion Battery Ceramics: Structural and Microstructural Evolution Mechanisms of Processing under an Electric Field

非技术描述：本项目探讨了一个基本假设，即在陶瓷，特别是锂离子电池相关陶瓷的加工过程中施加电场，对其孔隙度、致密性，并最终对电池本身的可靠性产生重大影响。该结果将用于合理设计具有目标性能的改进锂离子电池相关材料，克服当前在电化学和阻抗性能方面的障碍。所获得的基础知识将通过揭示一个有争议的话题（电场对陶瓷的影响）来影响陶瓷加工领域，同时包括锂离子电池领域的基本进展。该项目还将教育和培训结合起来，包括本科研究经历，以及网络实验和计算材料科学学习模块。该学习模块特别侧重于陶瓷材料主题背景下的综合实验和计算学习，这是普渡大学开设的两门课程的一部分。技术细节：本研究的目标是在基础层面上了解电场应用对锂离子电池相关陶瓷材料受控加工的影响。本研究选择的模型材料是钠超离子导体（Nasicon）陶瓷，Li1.5Al0.5Ge1.5(PO4)3 (LAG)（一种具有高离子电导率的电解质材料）和磷酸钒锂（Li3V2(PO4)3） （LVP）（一种既可以作为阴极也可以作为阳极的材料）。电池的性能和可靠性与组件材料中的不均匀性和微结构缺陷密切相关。本项目首先着重于开发和应用一个实验验证的微观结构和孔隙演化火花等离子烧结（SPS）相场烧结模型。接下来，实验设计将利用这些建模结果验证电场对模型系统（LVP、LAG和LVP/LAG）烧结、空位迁移、扭曲度、微观结构不均匀性和孔隙演化的影响。研究的第三步使用先进的模拟模型，包括热和电场的贡献，以及压力和快速加热制度对模型材料在SPS加工过程中的生长现象。最后，利用之前的结果建立了一个包含实际SPS烧结制度的实验模型，该制度包含完整的SPS烧结实验参数（电场、温度、加热速率和压力），以处理具有可控孔隙率和最小扭曲度的样品。

NON-TECHNICAL DESCRIPTION: This project explores the fundamental hypothesis that applying an electric field during processing of ceramics, in particular lithium-ion battery relevant ceramics, has a significant effect on their porosity, densification, and ultimately on the reliability of the battery itself. The results will be used for the rational design of improved Li-ion battery relevant materials with targeted properties that overcome the current hurdles in their electrochemical and impedance performance. The fundamental knowledge acquired will impact the ceramics processing field by shedding light on a controversial topic (electric field effects on ceramics), and at the same time including fundamental advancements in the Li-ion battery field. The project also integrates education and training by incorporating both undergraduate research experiences, and a cyber-enabled experimental and computational materials science learning module. The learning module has a specific focus on integrated experimental and computational learning within the context of ceramic materials topics that are part of two courses offered at Purdue University.TECHNICAL DETAILS: The goal of this research is to reach an understanding, at a fundamental level, of the effect of the electric field application on the controlled processing of Li-ion battery relevant ceramic materials. The model materials of choice for this study are a sodium superionic conductor (Nasicon) ceramic, Li1.5Al0.5Ge1.5(PO4)3 (LAG) (an electrolyte material with high ionic conductivity), and lithium vanadium phosphate (Li3V2(PO4)3) (LVP) (a material that can serve both as a cathode and as an anode). Battery performance and reliability are closely related to the presence of inhomogeneities and microstructural defects in the component materials. This project first focuses on the development and application of an experimentally validated microstructural and porosity evolution spark plasma sintering (SPS) phase field sintering model. Next, the experimental design is using these modeling results to verify the influence of electric field in terms of sintering, vacancy migration, tortuosity, microstructural inhomogeneity and porosity evolution in the model systems (LVP, LAG, and LVP/LAG). The third step of the research uses advanced simulation models to include thermal and electric field contributions, as well as pressure and rapid heating regimes to the growth phenomena during SPS processing of the model materials. Finally, the previous results are used to set up an experimental model to include actual SPS sintering regimes that contain the integrated SPS sintering experimental parameters (electric field, temperature, heating rate, and pressure) towards processing of samples with controlled porosity and minimal tortuosity.