A Novel Non‐Flammable Inorganic Liquid Electrolyte with Ultra‐High Voltage Stability for Li‐Ion Batteries

The growing demand for high‐performance energy storage has driven the search for advanced electrolytes in lithium‐ion batteries (LIBs). Organic electrolytes (OEs) contribute to battery performance through their relatively good ionic conductivity and moderate temperature tolerance. However, their flammability and limited electrochemical stability, particularly at higher voltages pose significant safety risks and can reduce battery lifespan. We introduce a novel ultra‐high‐voltage (UHV), non‐flammable inorganic liquid electrolyte based on a proprietary fluorinated salt in SO 2 , stable to 5.2 V. It delivers high ionic conductivity (37.9 mS/cm at 25 °C; 21.1 mS/cm at −20 °C) and operates from −40 °C to 60 °C. By suppressing cathode oxygen release, it minimizes harmful side reactions, extending cell longevity. Testing with NMC811, LMR, and LMFP cathodes at 4.7 V yielded record specific capacities of 255, 299, and 158 mAh/g, respectively. Full‐cells paired with graphite retained 90%, 81%, and 73% capacity after 1,200 cycles with ≈99.98% coulombic efficiency. In 21700 formats, the electrolyte enables 300 Wh/kg without adding silicon materials in the graphite anode. The thermal energy released during thermal runaway is reduced by 43% compared to OE. At −40 °C, cells maintained 83% of residual capacity. This technology offers improved safety, broad temperature tolerance, and exceptional electrochemical performance, offering a clear path to next‐generation, sustainable LIBs.