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·g−1 at 0.3 A·g−1. Furthermore, this capacitance also showed good electrochemical stability and a high degree of reversibility in the repetitive charge/discharge cycling test.