Ethylene carbonate (EC)-propyl acetate (PA) based electrolyte for low temperature performance of li-ion rechargeable batteries

Charge-discharge performance at -30°C was studied using low-viscosity ester solvents (propyl acetate (PA), propyl propionate (PP), and ethyl propionate (EP)) as electrolyte for improving the low-temperature performance of li-ion rechargeable batteries. Among the studied ester, PA based electrolyte showed the most superior cycle stability. EC-PA based electrolyte increased the discharge capacity of the cell at -30°C by 6% compared to the EC-DEC based electrolyte. Although the cell capacity at low temperature was increased, favorable solid electrolyte interface (SEI) may not be formed and the cycle stability was decreased in the cell using PA component as the electrolyte. Using an electrolyte additive for SEI formation in combination with PA based electrolyte, the low temperature discharge capacity and cycle stability were much increased which was strongly demanded for electric vehicle application.