Flexible poly(vinylidene fluoride-co-hexafluoropropylene)-based gel polymer electrolyte for high-performance lithium-ion batteries

Gel polymer electrolytes (GPEs) have attracted ever-increasing attention in Li-ion batteries, due to their great thermal stability and excellent electrochemical performance. Here, a flexible poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP)-based GPE doped with an appropriate proportion of the PEO and SiO2 is developed through a universal immersion precipitation method. This porous PVDF-HFP-PEO-SiO2 GPE with high ionic conductivity and lithium-ion transference number (tLi+) can enhance the electrochemical performance of LiFePO4 cells, leading to superior rate capability and excellent cycling stability. Moreover, the PVDF-HFP-PEO-SiO2 GPE effectively inhibits the lithium dendrite growth, thereby improving the safety of Li-ion batteries. In view of the simplicity in using the gel polymer electrolyte, it is believed that this novel GPE can be used as a potential candidate for high-performance Li-ion batteries.