Citric acid induced enhancement in capacitive performances of polyaniline/graphene gel electrode for flexible supercapacitors

Abstract A composite hydrogel electrode for a flexible supercapacitor was fabricated by dispersing polyaniline/graphene composite into a polyvinyl alcohol gel network in the presence of citric acid. It was found that the introduction of citric acid could greatly promote the capacitive performances of composite gel electrodes. The assembled flexible supercapacitor could exhibit a maximum specific capacitance of 321.3 F g −1 at 1 A g −1 with a capacitance retention rate of 76.0% (from 1 A g −1 to 20 A g −1 ). Furthermore, even after enduring 5000 cycles at 20 A g −1 , the supercapacitor maintained 86.8% of its initial capacitance, demonstrating excellent cycling stability. This work indicated that the introduction of multifunctional organic acid offered a more efficient pore structure for facilitating charge transport and dextral charge storage for gel electrodes, as a result, significant enhancement in capacitive performances.