Assessment of Safety Concerns in Sodium‐Ion Batteries

Abstract Sodium‐ion batteries (SIBs), lauded as the ideal complement to lithium‐ion batteries (LIBs) and a promising substitute for lead‐acid batteries, are now making strides in demonstration applications. Nevertheless, amidst the pervasive safety incidents plaguing LIBs, whether SIBs will fall prey to analogous pitfalls remains an open question, casting a veil of uncertainty over their developmental trajectory. Here, a thorough investigation into the safety of SIBs is conducted, with a focus on exothermic decomposition reactions at the electrode‐electrolyte interphase, using comprehensive thermal analysis. a critical perspective is offered, highlighting that quasi‐metallic Na clusters and plated sodium dendrites on hard carbon anodes, along with significant gas production, can be the main hurdles impeding the safe application of SIBs. The cautionary experimental findings reveal that Ah‐grade pouch‐type SIBs demonstrate thermal safety levels on par with, or even lower than, those of their lithium‐ion counterparts. This serves as an urgent imperative to unravel their unique thermal runaway failure pathways and engineer preemptive safeguards prior to large‐scale implementation.