The effect of poly(hydroxyl ethyl methacrylate) on the performance of PVDF/P(MMA-co-HEMA) hybrid gel polymer electrolytes for lithium ion battery application

Gel polymer electrolyte (GPE) membranes containing poly(vinylidene fluoride) (PVDF), PVDF/SiO2-g-poly(methyl methacrylate) (PMMA) and PVDF/SiO2-g-p(methyl methacrylate-co-hydroxyl ethyl methacrylate) (PMMA-co-HEMA) organic-inorganic hybrid nanoparticles were prepared by phase inversion method, in which PMMA and P(MMA-co-HEMA) were successfully grafted onto the surface of SiO2 nanoparticles by the atom transfer radical polymerization method. The structure and properties of the membranes were characterized using the Fourier transform infrared spectroscopy (FT-IR), H-1 nuclear magnetic resonance (H-1 NMR), thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) techniques. In addition, the performances of pristine PVDF and PVDF nanocomposites based gel polymer electrolytes in terms of ionic conductivity, linear sweep voltammetry (LSV), C-rate and cycling performance were investigated. The performance of the prepared membranes combined with 1 M LiClO4 in propylene carbonate improved by introducing HEMA groups (GPE3). The ionic conductivity of GPE3 was 2.63 mS cm(-1) at 298 K. The electrochemical stability window of SiO2-g-P(MMA-co-HEMA) containing GPE was established to be as high as 4.8 V (vs. Li/Li+). Besides, the Li/LiMn2O4 cell with the GPE3 showed excellent cyclic stability and rate performance. The results suggest the GPE3 is promising to be applied for rechargeable Li batteries with high safety and long cycle life.