Design and synthesis of NiCo₂O₄@Au@NiO sandwiched coaxial core–shell nanowire arrays on carbon fabric for high-performance supercapacitor

We developed a facile synthetic method to construct novel sandwiched coaxial core–shell heterojunction electrodes by combining NiO nanosheets wrapped in 1D NiCo₂O₄@Au nanowires with carbon fibre cloth (denoted NiCo₂O₄@Au@NiO). XRD, SEM and TEM techniques were used to characterize the structure of NiCo₂O₄@Au@NiO. Electrochemical measurements confirmed that the nanostructured composite had an electrochemical capacitance that was greater than that of each individual component due to synergistic effects. The NiCo₂O₄@Au@NiO electrode had an extremely high specific capacitance (163.1 mAh g⁻¹ at 0.5 A g⁻¹) and excellent cycling stability (90.2% after 10,000 cycles) in a three-electrode system with a 2 M KOH electrolyte. Furthermore, the performance of the asymmetric supercapacitor NiCo₂O₄@Au@NiO//AC was evaluated, and the energy density was 65.5 Wh kg⁻¹ at a power density of 375 W kg⁻¹. The excellent electrochemical capabilities of the nanoscale architecture electrodes provide a new route for developing high-performance supercapacitors with 3D multicomponent heterojunction core–shell structures.