The scrupulous designation of hollow and porous electroactive materials incorporating prolific redox-active polyphase transition-metal oxide decorated with polyphase transitionmetal 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 NiMoO 4 nanotubes onto rGO-coated Ni foam (rGO− NiMoO 4 @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 NiMoO 4 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−NiMoO 4 @ 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−NiMoO 4 @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.

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To meet the requirement for the high-ranked positive electrode materials having auspicious pseudocapacitive features for potential application in energy storage devices, the suitable designs of unique core−shell heterostructures featuring mixed transition metal oxide and layered double hydroxide (LDH) are highly needed and have been progressing expeditiously in recent years. Herein, 3D hierarchical zinc−nickel−cobalt (ZNCO)@Co−Ni-LDH (LDH-1 and LDH-2) core−shell nanostructured arrays on Ni foam as a pseudocapacitive electrode are prepared by using a facile hydrothermal and metal−organic framework (MOF) assisted coprecipitation method. FE-SEM images show that the core 1D ZNCO and shell 2D Co−Ni-LDH are well interconnected to form 3D porous and hierarchical ZNCO@Co−Ni-LDH core−shell nanostructures, leading to the fast and efficient transmission/transfer of both electrolyte ions and electrons, due to the higher electroactive surface areas and enhanced electrical conductivity. In a three-electrode system, the ZNCO@Co−Ni-LDH-2 electrode material delivers excellent electrochemical performance with higher specific capacitance of 2866 F g −1 at 1 A g −1 with ultrahigh capacitance retention of 68.35% at a higher current density of 10 A g −1 and excellent life span of 89% capacitance retention after 8000 cycles. Moreover, the sandwiched asymmetric supercapacitor (ASC) device using ZNCO@Co−Ni-LDH-2 as the positive electrode and N-doped graphene hydrogel (NGH) as the negative electrode exhibits superior specific capacitance (178 F g −1 at 1 A g −1 ), outstanding rate capability (70.22% at 10 A g −1 ), excellent life span (91.2% after 8000 cycles at 10 A g −1 ), and very high energy density (63.28 W h kg −1 at power density of 796.53 W kg −1 ).

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