Influence of State-of-Charge on the Thermal Stability of Solid-State Batteries

While solid-state batteries (SSBs) promise to offer higher energy densities and power densities when compared to current lithium-ion batteries, a comprehensive understanding of the electrode- and cell-level interactions affecting their safety is required. A wide range of mechanistic factors including the oxygen liberation from the cathode active material, cathode/anode crosstalk, interphase dynamics, and the melting point of lithium can affect the thermal stability of solid-state batteries. In this presentation, the impact of state-of-charge on the thermal runway pathway and exothermic response of solid-state cells, incorporating Li 6 PS 5 Cl as the solid electrolyte and LiNi 0.6 Mn 0.2 Co 0.2 O 2 (NMC622) as the cathode, is investigated using a combination of calorimetric measurements and mechanistic modeling. Through this analysis, the critical role of the cathode active material, solid electrolyte, and the cathode electrolyte interphase on key thermal stability descriptors including the onset of self-heating, thermal runaway onset temperature, maximum temperature reached during thermal runaway, and the peak rate of temperature rise has been delineated. This investigation underscores the complexities involved in evaluating the safety of SSBs, offering insights into the potential of SSB systems for safer energy storage.