Modish Designation of Hollow-Tubular rGO–NiMoO₄@Ni–Co–S Hybrid Core–shell Electrodes with Multichannel Superconductive Pathways for High-Performance Asymmetric Supercapacitors

The scrupulous designation of hollow and porous electroactive materials incorporating prolific redox-active polyphase transition-metal oxide decorated with polyphase transition-metal sulfide onto rGO (reduced graphene oxide)-supported conductive substrate has never been an easy task due to the very good coordination affair of sulfur toward transition metals. Herein, cost-effective hydrothermal growth followed by a metal–organic framework (MOF)-mediated sulfidation approach is employed to achieve burl-like Ni–Co–S nanomaterial-integrated hollow and porous NiMoO4 nanotubes onto rGO-coated Ni foam (rGO–NiMoO4@Ni–Co–S) as the electrode material for supercapacitors. The open framework of the rGO–Co–MOF template after the etching and sulfidation process not only enables the creation of a tubular structure of NiMoO4 nanorods but also provides convenient ion–electron pathways to promote rapid faradic reactions for the hybrid composite electrode. Owing to the unique hollow and tubular structure, the as-fabricated rGO–NiMoO4@Ni–Co–S electrode exhibits a high specific capacity of 318 mA h g–1 at 1 A g–1 and remarkable cyclic performance of 88.87% after 10,000 consecutive charge–discharge cycles in an aqueous 2 M KOH electrolyte on a three-electrode configuration. Moreover, the assembled rGO–NiMoO4@Ni–Co–S//rGO–MDC (MOF-derived carbon) asymmetric supercapacitor device exhibits a satisfactory energy density of 57.24 W h kg–1 at a power density of 801.8 W kg–1 with an admirable life span of 90.89% after 10,000 repeated cycles.