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Lithium difluoro(axalato)borate (LiODFB) was synthesized in dimethyl carbonate (DMC) solvent and purified by the method of solventing-out crystallization.The structure characterization of the purified LiODFB was performed by Fourier transform infrared (FTIR) spectrometry and nuclear magnetic resonance (NMR) spectrometry.The electrochemical properties of the cells using I mol/L LiPF6 and 1 mol/L LiODFB in ethylene carbonate (EC)/DMC were investigated,respectively.The results indicate that LiODFB can be reduced at about 1.5 V and form a robust protective solid electrolyte interface (SEI) film on the graphite surface in the first cycle.The graphite/LiNi1/3Mn1/3Co1/3O2 cells with LiODFB-based electrolyte have very good capacity retention at 55 ℃,and show very good rate capability at 0.5C and 1C charge/discharge rate.Therefore,as a new salt,LiODFB is a most promising altative lithium salt to replace LiPF6 for lithium ion battery electrolytes in the future.