Perspective on Thermal Stability and Safety of Sodium-Ion Batteries

Sodium-ion batteries (SIBs) are gaining traction as an emerging contender for sustainable and cost-effective energy storage, due to the abundance and low cost of sodium resources. Although notable advancements have been made in improving electrochemical performance, the thermal stability of SIBs and the role of intrinsic degradation pathways are yet to be fully understood. This Perspective examines the mechanistic interactions that drive thermal instability in SIBs across material, electrode, and cell levels under operational extremes and abuse conditions. We analyze the thermo-electrochemical characteristics of key electrode and electrolyte components, including their interphases, to identify the underlying factors responsible for the distinct thermal response of SIBs compared to lithium-ion batteries (LIBs). By benchmarking current SIB prototypes against commercial LIB technologies in terms of cost–performance trade-offs, we outline critical challenges that must be addressed to enable safe and scalable deployment of SIB systems.