Nonflammable sulfamoyl–carbonate hybrid electrolyte for high-voltage lithium batteries via preemptive passivation

Abstract Achieving high energy density without compromising safety remains a significant challenge for advanced batteries. Nonflammable electrolytes can mitigate fire risk, but poor bulk and interfacial properties of such electrolytes limit their application. Here, a nonflammable sulfamoyl–carbonate electrolyte was developed, achieving a self-extinguishing time of ~0 s and stable cycling in both lithium metal and lithium-ion batteries under high-voltage conditions. The electrolyte comprising lithium hexafluorophosphate dissolved in dimethylsulfamoyl fluoride, fluoroethylene carbonate, and ethyl methyl carbonate at low concentration establishes a weakly solvating environment, wherein dimethylsulfamoyl fluoride and fluoroethylene carbonate preferentially contribute to stabilize the positive and negative electrodes, while working together to enhance the rate capability, low-temperature performance, and long-term cycling at high-voltage. Accelerating rate calorimetry revealed a delayed thermal runaway onset by 87 °C, correlating with Broadness Index. These findings suggest that preemptive passivation on both electrodes, when coupled with nonflammable electrolyte design, can provide a viable route toward safe, high-energy lithium batteries.