Electrochemical functionalization of graphene nanosheets with iodoacetic acid towards supercapacitor electrodes

Abstract

Graphene nanosheets show great potential as electrode materials for supercapacitors due to their high surface area and excellent electrical conductivity. However, the low hydrophilicity of graphene nanosheets limits their electrochemical performance in aqueous supercapacitor applications. To enhance their electrochemical performance, we investigate the use of iodoacetic acid as an electrolytic functionalization agent for graphene nanosheets. Here, we demonstrate the successful electrolytic functionalization of graphene nanosheets under cathodic conditions in aqueous medium. The resulting material exhibits a high structural quality and carboxyl groups on the surface, which increases the hydrophilicity and wettability of the material. The applied voltage and the concentration of iodoacetic acid have been found to be key factors to optimize the process in order to get the maximum functionalization degree. The electrochemical performance demonstrates that iodoacetic acid functionalized graphene nanosheets exhibit significantly improved specific capacitance (220F/g at 0.5 A/g) and cycling stability of the symmetric cell compared to pristine graphene nanosheets, highlighting the potential of electrochemical functionalization to improve the performance of graphene-based materials in energy storage applications.