Development of Flexible Energy Storage Device by Using Polymer Electrolyte Based on Ionic Liquid

摘要

A flexible supercapacitor composed of the reduced graphene oxide / acid-treated single-wall carbon nanotubes (rGO/ ASWCNTs) composite (weight ratio of 1:9) electrode with the polymer based gel electrolyte was fabricated via spray coating technique. The ionic liquid based polymer electrolyte (IL-b-PE) was prepared by using polyvinyl alcohol (PVA) and 1-Butyl-3- methylimidazolium tetrafluoroborate (BMIMBF4), which was able to fabricate full device as flexible supercapacitor. The electrochemical performances evaluated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic charge / discharge (GCD) measurements. The flexible supercapacitor with the ionic liquid based polymer electrolyte (IL-b-PE) exhibited enhanced electrochemical performances compared to the flexible supercapacitor with PVA-H3PO4 gel electrolyte. The electrochemical properties of the flexible supercapacitor assembled by IL-b-PE were investigated as a function of bending cycles. The cycling stability of the flexible supercapacitor was analysed as the function of bending test (0~300) and GCD cycles (0~4000). The specific capacitance value of the flexible supercapacitor (unbent) was 62.4 F g~(-1), which decreased to 55.7 F g~(-1) (89.3% retention after 1000 GCD cycles. The flexible supercapacitor was retained 64.6% (40.3 F g~(-1)) of its initial capacitance value (62.4 F g~(-1)) after 300 bending with application 4000th GCD cycles.