High‐Voltage and High‐Safety Practical Lithium Batteries with Ethylene Carbonate‐Free Electrolyte

Abstract Serious safety issues are impeding the widespread adoption of high‐energy lithium‐ion batteries for transportation electrification and large‐scale grid storage. Herein, a triple‐salt ethylene carbonate (EC) free electrolyte for high‐safety and high‐energy pouch‐type LiNi 0.8 Mn 0.1 Co 0.1 O 2 |graphite (NMC811|Gr) cells is reported. This EC‐free electrolyte can effectively stabilize the NMC811 surface under high potential (up to 4.5 V), as well as generate a stable interphase to achieve a superior compatibility with the Gr anode. The electrolyte strategy enables significantly enhanced intrinsic safety (trigger temperature of thermal runaway (TR) increased by 67.0 °C), excellent electrochemical properties (4.2V, ≈100% after 200 cycles), and superior high voltage stability (4.5 V, 82.1% after 200 cycles). The work opens up a new avenue for developing novel electrolyte systems to build safer high‐energy batteries for practical applications.