Three Dimensional Sulfur-doped Graphene Hydrogels with Tetrathiafulvalene for High Performance Supercapacitors

By using tetrathiafulvalene as reducing and doping agents, three- dimensional ( 3D) sulfur- doped graphene hydrogels ( SGHs) were facilely prepared in mixed solvents of dimethyl formamide and water. Several investigations reveal that TTF plays a critical role in the formation of such unique 3D architecture, as it not only reduces GO to self- assembly into 3D structures, but also can be transformed to TTF+ and TTF2+ as doping agents in the reduction process. The morphology, crystal structure, chemical bonding, elemental composition and porosity of the as- prepared SGHs have been studied. Benefiting from well- defined and cross- linked 3D porous network architectures, the supercapacitors based on the SGHs in KOH electrolyte exhibited a high specific capacitance of 212.5 F center dot g(-1) at 0.3 A center dot g(-1). Furthermore, this capacitance also showed good electrochemical stability and a high degree of reversibility in the repetitive charge/ discharge cycling test.