All-climate outstanding-performances lithium-ion batteries enabled by in-situ constructed gel polymer electrolytes

Lithium-ion batteries (LIBs) with gel polymer electrolytes (GPE) employing highly volatile and extremely flammable linear carbonate solvents still face the safety hazard of fire and combustion. Gamma-butyrolactone (GBL) as electrolyte solvent can greatly improve the safety and all-climate performance of LIBs due to its higher flash point, lower vapor pressure, better thermal stability and wider liquid temperature range than those of the carbonate solvents. However, the application of GBL solvent is hindered by its incompatibility with the most widely used graphite anode. Herein, an all-climate high-power LiMn2O4 + LiMn0.7Fe0.3PO4/graphite pouch cell is achieved by employing non-flammable GBL-based GPE. The interphacial instability of GBL/graphite is solved by introducing three synergistic film-forming additives, including lithium bis(oxalato)borate, 4-vinyl-1,3-dioxolan-2-one and 3-sulfolene. The developed non-flammable GBL-based GPE enables the all-climate high-power LIBs application with great room-temperature rate capability, excellent low-temperature cranking and long elevated-temperature durability. More importantly, the developed pouch cells exhibit excellent cold-cranking performance even at −18 °C and maintain a high-capacity retention of 80 % after 400 cycles at 1C at 25 °C.