Hierarchical porous reduced graphene oxide decorated with molybdenum disulfide for high-performance supercapacitors

Two-dimensional materials are relevant for supercapacitor applications due to their excellent electrical, thermal, and physical properties. In this study, one-pot solvothermal method with l-cysteine mixed in ethylene glycol is utilized to prepare S/N co-doped reduced graphene oxide, which is decorated with molybdenum disulfide. Furthermore, these two-dimensional sheets are found to form three-dimensional hydrogel architectures. Field emission scanning electron microscopy and high-resolution transmission electron microscopy show this compound gel with hierarchical porous structure. The specific surface area of this compound gel is estimated to 151.41 m2 g−1, which is larger than that of S/N co-doped reduced graphene oxide gel (28.98 m2 g−1). This composite is used to fabricate binder-free electrodes. The electrochemical tests reveal high specific capacitance of the electrodes reaching up 400.10 F g−1 at a current density of 1 A g−1. The symmetric supercapacitors assembled by two similar S/N co-doped reduced graphene oxide/molybdenum disulfide electrodes deliver specific capacitance as high as 95.10 F g−1 at a current density of 1 A g−1 with capacitance retention of 91.32% after 5000 cycles. These results demonstrate that S/N co-doped reduced graphene oxide/molybdenum disulfide composite with hierarchical porous structure is promising binder-free material for high-performance supercapacitors.