High-performance and flexible electrochemical capacitors based on graphene/polymer composite films

Abstract

We report the fabrication of electrochemical capacitors (ECs) with high energy and power densities based on the compact reduced graphene oxide (rGO)/poly(vinyl pyrrolidone) (PVP) composite films. In these ECs, rGO/PVP composite films were directly used as the electrode material without blending any binders or conductive additives because of their high mechanical strength (121.5 ± 10.8 MPa) and electrical conductivity (247.9 S m⁻¹). The solid-state ECs based on the rGO/PVP composite containing 55% rGO (by weight) showed high gravimetric and volumetric specific capacitances, good rate-capability, excellent flexibility and satisfactory electrochemical stability. Furthermore, the EC based on the composite film containing 71% (by weight) of rGO with an organic electrolyte exhibited a high power density (40 W cm⁻³) and a high energy density (2.5 mW h cm⁻³) at a current density of 1 A g⁻¹ by taking account of the volumes of its electrodes and separator.