Materials Design for High‐Safety Sodium‐Ion Battery

Sodium‐ion batteries, with their evident superiority in resource abundance and cost, are emerging as promising next‐generation energy storage systems for large‐scale applications, such as smart grids and low‐speed electric vehicles. Accidents related to fires and explosions for batteries are a reminder that safety is prerequisite for energy storage systems, especially when aiming for grid‐scale use. In a typical electrochemical secondary battery, the electrical power is stored and released via processes that generate thermal energy, leading to temperature increments in the battery system, which is the main cause for battery thermal abuse. The investigation of the energy generated during the chemical/electrochemical reactions is of paramount importance for battery safety, unfortunately, it has not received the attention it deserves. In this review, the fundamentals of the heat generation, accumulation, and transportation in a battery system are summarized and recent key research on materials design to improve sodium‐ion battery safety is highlighted. Several effective materials design concepts are also discussed. This review is designed to arouse the attention of researcher and scholars and inspire further improvements in battery safety. This review summarizes the major heat generation sources, the electrochemical/chemical reactions that occur during thermal runaway processes, and recent progress in materials design for high safety sodium‐ion batteries. Minimizing irreversible heat Qp and side reaction heat Qs, accelerating the heat transport rate, and flame retardants would be effective directions to prevent fire or explosion accidents.