Study of poly (organic palygorskite-methyl methacrylate)/poly(vinylidene fluoride-co-hexafluoropropylene) blended gel polymer electrolyte for lithium-ion batteries

The composite membrane (PDFP-POPM) based on the blending of poly(vinylidene fluoride-co-hexafluoropropylene) (PDFP) and POPM (the copolymer of organic palygorskite and methyl methacrylate) was prepared by the phase-inversion method, and a gel polymer electrolyte (GPE) was obtained when the PDFP-POPM was activated by absorbing liquid electrolyte (LE). The SEM morphologies showed that the PDFP-POPM had a porous structure. The XRD results indicated that PDFP-POPM was an amorphous polymer and that the POPM could effectively suppress the crystallization of PDFP. The lithium ion transference number of GPE was higher than that of pristine POPM- and PDFP-based GPE. When the mass concentration of PDFP was 40%, the uptake of the PDFP-POPM and ionic conductivity of GPE reached the maximum values of 164% and 2.37 mS/cm, respectively. The electrochemical stability window of Li/GPE/SS batteries was over 4.7 V (vs. Li+/Li), and the Li/40PDFP-POPM GPE/LiFePO4 battery exhibited good cycling performance. The discharge capacity of the battery was 145mAh g−1 after 100 cycles and the columbic efficiency was over 95%.