Positive Electrode Performance of All-Solid-State Battery with Sulfide Solid Electrolyte Exposed to Low-Moisture Air

Abstract

All-solid-state batteries (ASSBs) using sulfide solid electrolytes (SEs) are attractive candidates as next-generation energy devices having longer lifetimes than liquid-type lithium-ion batteries (LIBs) using organic solvents. Sulfide SEs are known that to suffer a decrease in their ionic conductivity and generate toxic hydrogen sulfide when exposed to moisture even in an environment such as in a dry room. However, the influence of the exposure to moisture on the ASSB cell performance has not been fully elucidated so far. Aiming at filling this gap of knowledge, this paper describes the investigation of the influence of moisture on the durability of an ASSB positive electrode with sulfide SE unexposed or exposed to dry-room-simulated air with dew point of −20 °C in this study. After the cell durability evaluation, time-of-flight secondary-ion mass spectrometry (ToF-SIMS) measurements were performed on positive electrode, and a characteristic degradation mode was observed in the cell using the exposed SE.