Hybrid gel polymer electrolyte for high-safety lithium-sulfur batteries

A hybrid nanofiber PVDF-HFP polymer matrix with dispersed SiO2 nanoparticles was prepared by electrospinning, and 1M lithium bis(trifluoromethysulfonyl)imide (LiTFSI)/1-propyl-3-methylimidazolium bis(trifluoromethysulfonyl)imide (PMImTFSI) was incorporated in the hybrid polymer matrix to produce a polymer gel electrolyte for lithium-sulfur batteries. The PMImTFSI-based hybrid gel polymer electrolyte (ILGPE) reduced the concentration of Li+-coordinated TFSI, and the incorporation of PMImTFSI increased the α-phase content of PVDF-HFP, reducing polymer crystallinity. In addition, ILGPE showed high ionic conductivity, high oxidation potential (>5.0V vs. Li/Li+), and low flammability. The Li/S battery utilizing ILGPE showed a high initial discharge capacity of 1029mAhg–1 and maintained a stable capacity of 885mAhg–1 after 30 cycles at a current rate of 0.1C. [Display omitted] •A hybrid nanofiber polymer matrix with dispersed SiO2 nanoparticles was prepared by electrospinning.•ILGPE showed high ionic conductivity, high oxidation potential, and low flammability.•The Li/S battery utilizing ILGPE showed a good electrochemical performance.