Non-woven membranes based on poly(vinylidene fluoride-co-hexafluoropropylene) [P(VDF- HFP)] copolymer which contain microporous structure have been prepared by electrospinning method. The resulting polymer-ionic liquid electrolytes P(VDF-HFP)/EMIBF₄ possess an ionic conductivity of 8.43 mS•cm^－1 at room temperature and high temperature for initial weight losing over 300 ℃. The electric double-layer capacitors, applying the polymer-ionic liquid electrolytes as separator, were fabricated and tested. It exhibits excellent electrochemical properties, such as maintaining a specific capacity of 90.67 F•g^－1 even after 500 cycles at 1.0 mA•cm^－2 constant current charge-discharge and enjoying the cycling efficiency of 96.86%.

Key words: ionic liquid, electrospinning, polymer electrolyte, electric double-layer capacitor, ionic conductivity