How Safe Are Solid-State Batteries? Identifying Hazards with a Bottom-up Approach

With the growing need for high energy density batteries, lithium metal solid state batteries (LiSSB) have emerged as a promising candidate to achieve high performance metrics and cost-effectiveness. Additionally, LiSSBs boasted improved safety due to the replacement of flammable liquid electrolyte with non-flammable solids. However, this assumption of inherent improved safety has come into question. Different battery material sets present unique hazards that must be individually addressed. The early identification of unique hazards and failure mechanisms in prospective materials is critical for preventing safety-related setbacks and enabling swift and effective commercialization of next generation batteries. In this work, the thermal stability and hazards of promising LiSSBs and other next generation batteries are assessed through a multi-scale approach beginning at the materials level. The safety profiles of these prospective battery material sets are benchmarked against modern lithium-ion batteries. Through early hazard identification, mitigation strategies and inherently safer materials can be developed in parallel to performance metrics of next generation batteries, thereby enabling safe-by-design batteries.