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

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.