Dimethylsulfoxide-Dependent Environments for Fabricating Graphene Hydrogels for High-Performance Supercapacitor

In present work, reduced graphene oxide hydrogels (DRGHs) with three-dimensional (3D) porous structures are prepared through chemical reduction method by using dimethylsulfoxide (DMSO) as reductants in alkaline environment of ammonia. The reduction of graphene oxide (GO) into DRGHs was confirmed by X-ray powder diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FT-IR). The field emission scanning electron microscopy (FESEM) and high-resolution transmission electron microscopy (HRTEM) of DRGHs exhibited 3D structures with well-defined porous networks crosslinking of graphene sheets, which is beneficial to be promising electrode materials for supercapacitors. Moreover, the obtained DRGHs exhibited different electrochemical performance in supercapacitors with adding different amounts of DMSO. With increasing the dosage of the reductants, the DRGHs revealed better specific capacitances. DRGHs showed excellent capacitive performance with a very high specific capacitance up to 313.6, 323.6 and 348.0 F g_-1 for DRGHs-1, DRGHs-2 and DRGHs-3 at 0.2 A g_-1, respectively. It also showed that the electrode based on DRGHs has good stability and high reversibility in the charge/discharge cycling test.