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

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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.