Understanding on the effects of chemical reaction at cathode-electrolyte interface in sulfide based all-solid-state batteries
Journal
Journal of Materials Chemistry A
Date
2019.10.28
Abstract
Driven by a paradigm shift from conventional liquid-based systems to all-solid-state batteries (ASSBs), the chemo-mechanical behavior of the solid-solid interface is of growing importance for understanding the intricate interfacial phenomena of ASSBs. At the interfaces, various degradation factors of the cells, such as electrochemically driven volume changes and highly reactive cathode, are correlated to the chemical reaction at the interface between the solid materials, involving the diffusion of chemical species at the junction that occurs immediately after cell assembly. This makes it hard to understand the ASSB system. In this study, we investigate the effect of chemical reaction between a discharged cathode and a sulfide-based electrolyte without electrochemical cycling. We reveal that the chemical reaction can greatly influence the cell performance by forming products different from those commonly observed after electrochemical cycling. We also find physical contact-loss between them, implying that mechanical and chemical degradations occurred simultaneously. The complex chemo-mechanical degradation increased ionic resistance at the grain boundary, resulting in inferior initial reversible capacity. Our research provides an insight into the complex behaviors at the solid-solid interface in sulfide-based ASSBs.