Cross-Sectional Stress Evolution in Nanostrucured CAT blends of Solid-State Li-ion Batteries: Operando WAXS Studies

Most Li-ion battery cathodes undergo volume changes, impacting electrochemical performance and mechanical stability. Solid-state Li-ion batteries (SSLIB) worsen this with repetitive volume changes inducing mechanical fatigue, causing failures like delamination at cathode/solid electrolyte (SE) interfaces. True solid-state batteries need CAT materials with small strain or strain accommodation via composite cathode microstructure design. In the EU M.ERA.NET project, we focus on designing "zero-strain" CATs using material blends with opposite expansion coefficients in various nanoscale structures to minimize volume changes. Our experiment aims to quantify cross-sectional stress distribution during lithiation and delithiation at different c-rates using X-ray nanodiffraction, revealing how CAT blend type and nanostructure correlate with electro-chemo-mechanical behavior. This investigation into interfacial stress during cycling holds potential for advancing "zero-strain" cathode research.