Co-polymerization and blending based PEO/PMMA/P(VDF-HFP) gel polymer electrolyte for rechargeable lithium metal batteries

A novel gel polymer electrolyte (GPE) is prepared based on the co-polymerization of vinylidene fluoride (VDF) and hexafluoropropylene (HFP), the blending of the copolymer P(VDF-HFP) with poly(ethyleneoxide) and Poly(methylmethacrylate), and the absorption of liquid electrolyte of lithium hexafluorophosphate (LiPF6) in ethylene carbonate (EC) + dimethyl carbonate (DMC) (1:1 v/v) as the plasticizer. This GPE has more amorphous region, and can accommodate larger amount of liquid electrolyte via its porous structure without leakage, which provide an ionic conductivity of 0.81 mS cm−1 at 25 °C. Furthermore, the GPE possesses a high electrochemical window of 5.0 V (vs. Li/Li+), superior thermal stability, large Li+ transport number and excellent interface stability to Li metal anode. The test cells with the GPE, Li metal anode and LiCoO2 cathode show a superior cycling stability and rate performance. This GPE is promising to be applied to rechargeable Li batteries with high safety and long cycle life.