Tuning graphene surface chemistry to prepare graphene/polypyrrole supercapacitors with improved performance

A series of functionalized graphene derived from graphite oxide (GO) and doped with polypyrrole (PPy) are prepared to systematically investigate the combined effect of surface functionalization and polymer hybridization on supercapacitor performance. Surface chemistry of graphene is found to be of significant importance to PPy growth and PPy/graphene electrochemical performance improvement. High specific capacitance has been achieved by N doped graphene/polypyrrole (NG-PPy) electrode with a value of 393.67Fg ^-1, which is larger than those of -NH ₂ modified graphene/PPy (225.33Fg ^-1), GO/PPy (165.25Fg ^-1), reduced GO/PPy electrodes (150.00Fg ^-1) under the same experimental conditions. Incorporation of N into the graphene network enhances electronic transfer efficiency and improved graphene surface wettability, therefore, largest synergistic effect is achieved on NG-PPy. Introduction of N doping to carbon material before the growth of conducting polymer is essential to prepare carbon/conducting polymer composites with high cycling stability and specific capacitance for supercapacitor application.