Assessment of Thermal Safety for Organic Electrolytes: from Material to Cell Level

Thermal safety is a key bottleneck in the development of high-energy-density batteries, primarily due to the high volatility and flammability of organic electrolytes. Efforts to enhance battery safety focuses largely on making electrolytes flame-retardant to prevent ignition. However, the direct correlation between electrolyte nonflammability and battery thermal safety could be misleading, as the intricate cell environment may deviate the actual battery safety performance from the material-level design. Therefore, clarifying other influential factors beyond flammability and establishing multiscale and quantitative assessment metrics are highly crucial. In this Perspective we discuss the key factors and characterization methods for evaluating the thermal safety of electrolytes from the material to the cell level and simultaneously provide insights into standardization of measurement protocols. Finally, a brief outlook on future directions in electrolyte thermal safety assessment is presented. This perspective may inspire more efforts toward advanced characterization techniques and comprehensive safety evaluation frameworks, further paving the way for safer and more reliable energy storage technologies in the future.