Electrochemical studies on polymer electrolytes based on poly(vinylidene fluoride-co-hexafluoropropylene) membranes prepared by electrospinning and phase inversion-A comparative study

摘要

The synthesis, characterization and electrochemical properties of poly(vinylidene fluoride-co-hexafluoropropylene) {P(VdF-co-HFP)} prepared by electrospinning and phase inversion methods are reported. The morphologies of the membranes were studied by field emission scanning electron microscope and atomic force microscope. Thermal properties of the membranes were evaluated by differential scanning calorimetry. The resultant porous membranes are good absorbents of liquid electrolytes and exhibit high electrolyte retention capacity. The polymer electrolytes were prepared by soaking the membranes in liquid electrolyte. The temperature dependent ionic conductivity and electrochemical properties were evaluated. Li/LiFePO_4 cell with electrospun membrane delivers a discharge capacity of 145 mAh/g, which corresponds to 85% utilization of active material under the test conditions and shows lower capacity fade under continuous cycling.