Unraveling the electrothermal reactivity of FEC-based electrolytes for practical LiNi_0.92Co_0.04Mn_0.04O₂||Graphite pouch cells

Lithium-ion batteries are widely used due to high specific energy, but the ethylene carbonate in the electrolyte reacts violently with the oxygen component produced by the nickel-rich cathode, leading to lithium precipitation. For this reason, we propose a new electrolyte with Fluorine ethylene carbonate as the main solvent, which replaces the reaction source. It is verified that the capacity retention rate of the FEC-based battery reaches 96% after 300 cycles. Besides, FEC-based batteries withstand severe nail penetration tests without thermal runaway. In a heating test, the thermal runaway trigger for the FEC-based battery was delayed by 54 s. This work provides ideas for the subsequent development of safe electrolytes.