Calendar Aging of Sulfide All-solid-state Batteries

Sulfide solid-state electrolytes (SEs), prized for high ionic conductivity and mechanical strength, face practical challenges due to multi-field coupling failures under operational stresses. While prior studies emphasize electrochemical degradation (e.g., interfacial reactions, Li dendrites), thermal failure mechanisms during high-temperature storage remain overlooked. This work systematically explores calendar aging in sulfide-based all-solid-state batteries (ASSBs). Among tested systems, LiCoO₂ (LCO), Li 6 PS 5 Cl, and Li-In alloy exhibit superior stability after high-temperature storage. However, high-voltage LiNi 0.8 Co 0.1 Mn 0.1 O₂ (NCM811) undergoes structural collapse, releasing decomposition products that accelerate interfacial reactions and thermal failure. Batteries at high states of charge (SOC) experience intensified self-discharge-driven electrode-electrolyte reactions at elevated temperatures. In contrast, LCO-Li 6 PS 5 Cl-LiIn ASSBs at 0 SOC retain nearly undegraded performance after 5 days at 90°C. Suppressing the detrimental H3-phase transition in NCM811 improves capacity retention by ≥21%. The study elucidates high-temperature degradation pathways in sulfide ASSBs, linking thermo-electro-chemical coupling effects to interfacial ion transport barriers and contact degradation. These insights advance the understanding of calendar aging mechanisms, providing critical guidance for predicting battery lifespan and designing robust electrode/electrolyte systems.