3D hybrids based on WS2/N, S co-doped reduced graphene oxide: Facile fabrication and superior performance in supercapacitors

Abstract

To further enhance electrochemical performance of WS2-based materials in supercapacitors, a 3D architecture with WS2 nanoflakes interconnected and quantum dots anchored on N and S co-doped reduced graphene oxide (WS2/N,S-rGO) crumpled nanosheets is fabricated for the first time via a novel, facile and scalable approach, which is based on rapid solution combustion synthesis of the precursor and subsequent gas-solid phase sulfurization, and needs no such tedious processes as filtration, washing and drying. Significantly, the WS2/N,S-rGO hybrid possesses a specific capacitance of 1562.5 F g−1 at 1 A g−1 and a rate capability of 780 F g−1at 40 A g−1, which are superior to the currently-reported WS2-based electrode materials. As to the WS2/N,S-rGO hybrid, the 3D hierarchical architecture, synergistic effect between WS2 and N,S-rGO nanosheets as well as nitrogen and sulfur co-doping on rGO offer a variety of advantages such as larger contact surface area, shorter ion diffusion path, excellent charge transport and especially the enhanced pseudo-capacitance of rGO, and thus result in huge improvement in electrochemical activity, which demonstrate the WS2/N,S-rGO hybrid to be a superb anode material in supercapacitors.