Ultrafast high energy supercapacitors based on pillared graphene nanostructures

Abstract

Herein we report the optimized growth of pillared graphene nanostructures (PGNs) on nickel foil substrates. Supercapacitors (SCs) are fabricated based on the as-grown PGN electrodes. The resulting SC allows for operation with excellent rate performance and reversibility at rates up to 100 V s⁻¹. A large operational voltage window of 2.8 V and high specific capacitance of 144.5 F g⁻¹ are achieved in organic tetraethyl ammonium tetrafluoroborate (TEABF₄) electrolyte which leads to an energy density of 52.45 W h kg⁻¹ and a superior power density of up to 102.5 kW kg⁻¹. Moreover, the capacitance retention of 98% (near 100% columbic efficiency) over 30 000 charge–discharge cycles demonstrates the excellent cycling stability and electrochemical reversibility of the PGN based SC. These merits enable the 3D PGN to serve as high performance SC electrodes, resulting in energy storage devices with superb cycling stability and outstanding power density.