A study on PVDF-HFP gel polymer electrolyte for lithium-ion batteries

Abstract

In this paper, poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) gel polymer electrolyte was fabricated via solvent casting method in order to improve the performance of the lithium-ion batteries. By comparing the physical and electrochemical properties of PVDF-HFP gel polymer electrolyte with three different proportions, the optimization of the PVDF-HFP gel polymer electrolyte was obtained: 10wt% PVDF-HFP - 80wt% tetrahydrofuran (THF) / acetone - 10wt% 1mol L^-1 lithium perchlorate (LiClO₄) in elthylene carbonate (EC) and diethyl carbonate (DEC). The optimized PVDF-HFP gel polymer electrolyte displayed a high conductivity of 1.06×10^-3 S cm^-1 at room temperature, a high lithium transference number of 0.36 and a good thermal stability within 100°C. Moreover, the discharge specific capacity was 135.1 mAh g^-1, and the charge / discharge efficiency was 99.1% at 0.1C rate. Therefore, the fabricated PVDF-HFP gel polymer electrolyte was an effective gel polymer electrolyte to be applied on lithium-ion batteries.