Understanding failure mechanisms in solid-state batteries at the cathode/electrolyte interface using XRD-CT and XCT

All solid-state batteries (ASSBs) with Li-metal anodes are a promising solution to enable safe, high-capacity Li-ion batteries. ASSBs have challenges that need to be resolved to enable their use, including cracking of the cathode and loss of contact between the cathode / solid-state electrolyte (SSE) due to volumetric expansion/contraction during lithiation. X-ray diffraction computed tomography (XRD-CT) combined with x-ray absorption/phase CT (XCT) can be used to inform a 3D understanding of the cathode/SSE interface changes with cycling and the heterogeneity of these mechanisms. We propose to use these techniques on two SSEs: on LLZO, a popular high conductivity SSE, and on a new class of SSEs we have developed based on substituted forms of the popular Li6PS5Cl SSE. This study will provide important insight into the failure mechanisms of ASSBs and help guide future development of SSEs.