A 3D walking palm-like core-shell CoMoO@NiCoS@nickel foam composite for high-performance supercapacitors.

Supercapacitors are one of the most promising renewable-energy storage systems. In this study, a three-dimensional walking palm-like core-shell CoMoO4@NiCo2S4@nickel foam (NF) nanostructure was synthesized using a two-step hydrothermal method for high electrochemical performance. The as-prepared composite exhibited a high areal capacitance of 17.0 F cm-2 (2433 F g-1) at a current density of 5 mA cm-2 in a three-electrode system. The results revealed outstanding cycling stability of 114% after 10 000 charge-discharge cycles. An aqueous asymmetric supercapacitor device assembled with CoMoO4@NiCo2S4@NF and activated carbon (AC)@NF as the positive and negative electrodes, respectively, showed a high capacitance of 4.19 F cm-2 (182 F g-1) and delivered a high energy density of 60.2 W h kg-1 at a power density of 188 W kg-1 and a high power density of 1.5 kW kg-1 at an energy density 29.2 W h kg-1, lighting 22 parallel-connected red light emitting diodes for over 60 s. The synergistic effects of the core-shell CoMoO4@NiCo2S4@NF electrode material highlight the potential of this composite as an effective active material for supercapacitor applications.