A high-performance all-solid-state supercapacitor with graphene-doped carbon material electrodes and a graphene oxide-doped ion gel electrolyte

Two major issues of conventional supercapacitors, composed of a separator, two electrodes, and liquid electrolyte, are their low package energy density and the leakage of the liquid electrolyte. Therefore, great efforts have been dedicated in development of all-solid-state supercapacitors with higher energy density. Here we demonstrate a high-performance all-solid-state supercapacitor with a graphene-doped carbon electrode material and a graphene oxide (GO)-doped ion gel as a gel polymer electrolyte and separator. Because of the ultrahigh specific surface area (3193 m(2) g(-1)), suitable pore-size distribution (primarily 1-4 nm), and excellent electrical conductivity (67 S m(-1)) of the graphene-doped carbon material, as well as the broad electrochemical window (0-3.5 V) and high ionic conductivity of the GO-doped ion gel, the all-solid-state supercapacitor demonstrates outstanding performance with a specific capacitance of 190 F g(-1) and energy density of 76 Wh kg(-1) at 1 A g(-1), and a specific capacitance of 160 F g(-1) and energy density of 57 Wh kg(-1) at 10 A g(-1). In addition, the all-solid-state supercapacitor exhibits similar and excellent performance as does the compared conventional liquid supercapacitor in respect of specific capacitance, capacitance retention, internal resistance, and frequency response. (C) 2014 Elsevier Ltd. All rights reserved.