Blending-based poly(vinylidene fluoride)/polymethyl methacrylate membrane for rechargeable lithium-ion batteries

A gel polymer electrolyte based on the blending membranes of poly(vinylidene fluoride) (PVDF)/polymethyl methacrylate (PMMA) has been manufactured through the non-solvent-induced phase separation (NIPS) method. Its physical and electrochemical properties are characterized, and the blending compatibility of the PVDF/PMMA polymer is demonstrated by thermodynamic analysis. The increase in PMMA content has a great effect on surface morphologies of the PVDF/PMMA blending membranes, especially in terms of PM-3 (membrane with the weight ratio of PVDF/PMMA = 6:4). The PM-3 membrane presents satisfactory ionic conductivity (2.18 mS cm−1 at 26 °C), acceptable thermal stability, and superior compatibility with lithium. In addition, its cycle performance (130.7 mAh g−1 after circulating 200 cycles at 1 C) and rate capability (133.3 mAh g−1 at 4 C) are superior to those of the Celgard 2320 (PP/PE/PP) separator. It is indicated that the PVDF/PMMA blending membrane is promising for the fabrication of rechargeable lithium-ion battery.