Toward an In‐Depth Fire Hazard and Resistance Diagnosis of Flame Retarded Liquid Electrolytes for Safer Lithium‐Ion Batteries

Abstract Growing reports of fire incidents originating from lithium‐ion batteries have led to a quest for safer lithium‐ion batteries. Although the commercial success of the lithium‐ion batteries owes a great debt to the liquid electrolyte as much as the electrodes, the liquid electrolyte is considered the most flammable component of the battery. Flame retardant additives offer a promising solution to alleviate electrolyte flammability since they are added in minute quantities. However, the fire resistance and hazard diagnosis of the flame retardant containing liquid electrolyte remains a challenge due to the lack of reliable characterization technology. Herein, a stainless steel sample holder is custom‐designed and integrated into the cone calorimeter, enabling a precise and reliable technique for diagnosing the fire resistance efficiency and hazards of flame retarded liquid electrolytes. This integration allows for real‐time analysis of key fire behavior parameters of the flame retarded electrolytes such as time to ignition, heat release rate, fire growth rate index, smoke toxicity index, carbon monoxide, and smoke produced. Most of the fire test results show high reproducibility with less than 10% error. This study indicates that the modified cone calorimetry is a promising technology for diagnosing flame retarded liquid electrolyte fire resistance and hazard.