Study on γ-butyrolactone for LiBOB-based electrolytes

To solve the problems of LiBOB-based electrolytes, small salt solubility and low conductivity, a sort of cyclic carboxylate, γ-butyrolactone (GBL) was applied in the lithium-ion battery electrolyte as the main solvent of lithium bis(oxalate)borate (LiBOB). LiBOB–GBL electrolyte exhibits good electrochemical stability, which is suitable to be the candidate of the lithium-ion battery electrolyte. Using GBL as the solvent of the LiBOB salt can increase the solubility and conductivity dramatically. At room temperature, LiFePO4/LiBOB–GBL/Li half cell shows satisfying cycle performance with no capacity fading in the first 50 cycles and promising capacity performance with stable discharge capacity of about 125 mAh g−1. EA is mixed with GBL to get lower viscosity solvent. In LiFePO4/Li half cell with 0.5 C discharge rate, 0.2 M LiBOB–GBL/EA (1:1, wt) electrolyte exhibits best at room temperature and 0.7 M LiBOB–GBL/EA (1:1, wt) electrolyte exhibits best at elevated temperature.