Understanding the effect of strain relief mechanisms on cycle life in solid-state batteries 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. Challenges for ASSBs include loss of contact between the cathode / solid-state electrolyte (SSE) due to volume change of the cathode during lithiation leading to inactive cathode particles and capacity fade. We have developed two new SSEs based on the popular Li6PS5Cl SSE which aim to provide improved strain relief throughout cycling, thereby maintaining contact with the cathode and improving cycle life. By using X-ray diffraction computed tomography (XRD-CT) correlated with absorption contrast x-ray computed tomography (XCT), we propose to study how stress from volume change of the cathode during cycling is relieved via (a) strain fields within the SSE and (b) delamination between cathode particles and the surrounding SSE. Finally, we aim to establish a link to the subsequent heterogeneous lithiation of the cathode particles and the resulting capacity fade.