Nanoporous graphene obtained by hydrothermal process in H2O2 and its application for supercapacitors

Highlights: • Nanohole graphene oxide was obtained by hydrothermal process in H₂O₂. • Superior specific capacitance was achieved by nanohole graphene oxide electrode. • Nanohole graphene oxide electrode also exhibited an excellent cycle stability. Nanohole graphene oxide (NHGO) was obtained in a homogeneous aqueous mixture of graphene oxide (GO) and H₂O₂ at 120 °C. Supercapacitors were fabricated as the electrode material by using NHGO. A specific capacitance of 240.1 F g⁻¹ was obtained at a current density of 1 A g⁻¹ in 6 m KOH electrolyte and specific capacitance remained 193.6 F g⁻¹ at the current density of 20 A g⁻¹. This was attributed to reducing the inner space between the double-layers, enhanced ion diffusion and large specific surface area. Supercapacitor prepared with NHGO electrodes also exhibited an excellent cycle stability.