A facile preparation of three dimensional N, S co-doped graphene hydrogels with thiocarbohydrazide for electrode materials in supercapacitor

Three-dimensional (3D) N, S co-doped graphene hydrogels (NSGHs) were facilely prepared by using thiocarbohydrazide as reducing and doping agents in an aqueous solution. Due to their porous architectures, the as-prepared NSGHs all exhibited high specific capacitance of 123.4, 120.9 and 141.1Fg−1 at 0.3Ag−1 for NSGHs-1, NSGHs-2, and NSGHs-5 in KOH electrolyte, respectively. Moreover, their specific capacitance can still be maintained for 72.3%, 59.4%, and 71.3% even with an increase of the discharging current density of 10Ag−1, respectively. Particularly, the NSGHs-5 based supercapacitor has exhibited excellent electrochemical stability and high degree of reversibility in the long-term cyclic test (90% retention after 4000 cycles).