Preparation, characterization and properties of poly(propylene carbonate)/poly(methyl methacrylate)-coated polyethylene gel polymer electrolyte for lithium-ion batteries

Abstract

A poly(propylene carbonate) (PPC)/poly(methyl methacrylate) (PMMA) polymer precursor was developed via solution polymerization with different mass ratios of methyl methacrylate (MMA) and PPC. Then, PPC/PMMA-coated Celgard PE membranes were prepared by the dip-coating method with this polymer precursor and activated to fabricate gel polymer electrolytes (GPEs). The structure and performance of the samples were characterized with FTIR, DSC, SEM, water contact angle analysis and electrochemical performance tests, such as electrochemical impedance spectroscopy (EIS), linear sweep voltammetry (LSV) and galvanostatic charge-discharge measurements. The effect of the ratio of MMA to PPC on the performance of the as-prepared PPC/PMMA-coated Celgard PE GPEs was considered. Benefiting from the composite structure, the GPE produced from the Celgard PE coating polymer with a PPC to MMA ratio of 8:2 (by weight) had the highest ionic conductivity and showed superior electrolyte wettability with 347% electrolyte uptake. Additionally, the as-prepared GPEs displayed good compatibility with the anodes and cathodes of lithium-ion batteries (LIBs), and their oxidation potentials were stable to 5.0V (vs Li/Li+). The LiFePO4 battery using this PPC/PMMA-coated Celgard PE GPE exhibited an excellent initial discharge capacity of 154mAhg−1, cyclic stability and rate capability.