Hot-Pressed FeS₂ Cathodes with Oxysulfide Solid-State Electrolyte for All-Solid-State Batteries

The performance of all-solid-state batteries (ASSBs) is limited by poor interfacial contact between active material (AM) and solid-state electrolyte (SSE) particles. At the cell level, poor interfacial contact manifests as difficult operating specifications (e.g. high stack pressure, elevated temperature, or slow charge rate), or poor cell durability. This seminar investigates how an advanced processing technique can better consolidate electrode composites. It will be shown that the electrochemical performance of FeS₂/InLi ASSBs was improved when the cells were hot-pressed at a temperature > 200 °C. When cycled at 25 °C, a cold-pressed (CP) FeS₂/InLi ASSB delivered negligible capacity whereas a hot-pressed (HP) FeS₂/InLi ASSB delivered a 1^st cycle discharge capacity in excess of 600 mAh g^-1. The improved performance is attributed to better interfacial contact between AM and SSE. This result was achieved by selecting thermally stable FeS₂ active material and highly processable Li₇P₃S_9.75O_1.25(LPSO) SSE.