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 m2 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.