Batwing-like polymer membrane consisting of PMMA-grafted electrospun PVdF-SiO2 nanocomposite fibers for lithium-ion batteries

To retain the electrolyte within the fibrous poly(vinylidene fluoride) (PVdF) membranes in a lithium-ion battery, poly(methylmethacrylate) (PMMA) was grafted onto electrospun SiO2-PVdF nanocomposite fibers via radical polymerization, producing a batwing-like polymer membrane. The obtained polymer membrane was activated with the electrolyte (1.0 M LiPF6 in a mixture of ethylene carbonate and diethylene carbonate) to form a fibrous gelled-polymer electrolyte (FGPE). The effects of grafting of PMMA on the morphology, mechanical properties, and electrochemical properties of the fibrous membranes were investigated. The SiO2-PVdF fibrous membrane that was grafted with 20 wt% of PMMA possessed an ionic conductivity of 2.31 x 10(-3) S cm(-1) at room temperature and a tensile strength of 8.2 MPa. The Li-LiFePO4 cells assembled by this FGPE delivered specific capacities of 156 and 130 mAh g(-1) at the rates of 0.1 and 2 C, respectively, and they retained 97% of the initial capacity at 0.1 C-rate after 90 cycles. The results indicate that FGPE is suitable for high-performance lithium-ion batteries. (C) 2015 Elsevier B.V. All rights reserved.