Enhanced Air-Stability of Argyrodite Solid Electrolyte By Introducing Zeolite Additive As H2s Scavenger

Abstract

All-solid-state batteries (ASB) have received great attention as a next generation power source due to its safe characteristics with non-flammable solid electrolyte. Whole battery reactions are occurred in solid-state Li+ migration in ASB, therefore the well-contacted interfacial area is critical for battery performance. Especially for ASB with high energy density, casting process is suitable to form a large sized sheet of electrode and electrolyte. When electrode and electrolyte sheets are fabricated by conventional cold pressing, sulfide solid electrolyte is favorable to form a contact area effectively due to its elastic powder character compared to oxide. However, sulfide solid electrolyte is chemically unstable with humidity in air. It easily generates H2S gas that is toxic and hazardous. Residual Li2S and bridge sulfur in structure are known as main cause of H2S generation. The ionic conductivity is also decreased by the decomposition of solid electrolyte by undesirable H2S generation. In this study, zeolite were used as additive for H2S scavenger. 5 wt% of zeolite additive was mixed with argyrodite-type Li6PS5Cl, then exposured in moisture air (Rh 50%). The amount of H2S gas generation was greatly reduced by introducing zeolite additive. Decease of ionic conductivity after air exposure is also suppressed by zeloite additive. It also affect to cell performance such as specific capacity and cycle performance. On the basis of these results, adding H2S scavenger is proposed as a visible method for enhancement of air-stability of sulfide solid electrolyte. The detailed results will be discussed at the meeting.