Facile preparation of binder–free electrode for electrochemical capacitors based on reduced graphene oxide composite film

Abstract Binder-free electrode based on reduced graphene oxide (rGO) is attracting attention for electrochemical capacitors. Here the binder-free electrodes have been fabricated by activating the composite films of GO and carbonized cornstalk-cores. In the composites, the rGO sheets are found to be tightly adhered to the activated bio‑carbon which is intercalated between the rGO sheets to prevent them from stacking. Moreover, the influences of the mass ratios of GO to bio‑carbon on the electrochemical performance have been systematically investigated. The optimal binder-free electrode (rGO/ACCS 1/1 ) prepared from the composite films with 1:1 mass ratio of GO to bio‑carbon exhibits a specific capacitance as high as 278 F g −1 at scan rate of 1 mV s −1 and shows excellent stability in 6 M KOH electrolyte. Furthermore, the optimal electrode can retain 47.8% of the initial specific capacitance even at current density of 100 A g −1 , indicating a fast charge-discharge capability. This work provides a simple method to prepare binder-free composite electrodes by introducing renewable and inexpensive biomass based carbon into activated rGO films.