Effect of 1- Pyrene Carboxylic-Acid Functionalization of Graphene on Its Capacitive Energy Storage

We report on the performance of supercapacitor devices fabricated using 1-pyrenecarboxylic acid (PCA)-functionalized graphene electrodes. The specific capacitances obtained (using 6 M KOH aqueous solution as an electrolyte) was found to be an order of magnitude higher than nonfunctionalized graphene electrodes (∼30 and ∼200 F/g for pure graphene and PCA-functionalized graphene electrodes, respectively). The analysis of electrochemical impedance spectroscopy using equivalent circuit modeling as well as electrolyte wettability measurements shows a substantial increase in the electrical double layer capacitance due to the PCA functionalization. These findings indicate that PCA functionalization of graphene can significantly enhance the capacitive storage ability of graphene-based electrodes and can act as superb electrode materials in electrical energy applications.