.A novel hybrid supercapacitor of Ni-CCH@MnNiCo-OH//ZIF-67-C-KOH was successfully fabricated with promising electrochemical storage properties.

A supercapacitor electrode with high capacitance is mainly based on the careful design of nanostructures and the intelligent hybridization of custom active materials. Herein, we designed 3D core-shell nanoforest arrays with hierarchical structure which are directly grown on carbon cloth using a two-step bracket-hydrothermal method and electrodeposition process. Due to the advantages of large specific surface area, abundant pores and active sites, the structure of Mo-Co-Ni(nanotube)@Ni-Co(nanosheet) arrays can promote electrolyte penetration and ions diffusion, further improving the electrochemical performance. The 3D core-shell nanoforest arrays electrode shows outstanding electrochemical performance: a superb areal capacitance of 9.81 F cm −2 (1998.0 F g −1 ) at the current densities of 1 mA cm −2 , as well as long cycle stability (after 3000 cycles maintains 85.4% of the highest capacitance value). This work may provide a promising method for design of flexible supercapacitor electrode materials.

Porous mesh‐like FeCo2S4 nanosheet arrays on Ni foam (NF) have been prepared by a two‐step hydrothermal approach and employed as electrodes for supercapacitors and efficient bifunctional electrocatalysts for water splitting. FeCo2S4/NF exhibits ultrahigh areal capacitance of 7.37 F cm−2 at current density of 5 mA cm−2 and achieves good cycling stability retaining 92% capacitance after 3000 cycles at 10 mA cm−2. Symmetric solid‐state device of FeCo2S4/NF as positive and negative electrodes delivers a remarkable energy density of 19.12 W h kg−1 (434.61 W kg−1). Furthermore, FeCo2S4/NF electrode delivers a low overpotential of 155 mV at a hydrogen evolution reaction (HER) current density of 10 mA cm−2 and shows no obvious attenuation after stability test for 100,000 s in 1 M KOH solution. While a low overpotential of 234 mV at 50 mA cm−2 for oxygen evolution reaction (OER) can be demonstrated in alkaline environment as an anode electrocatalyst. FeCo2S4/NF shows excellent activity toward overall water splitting with 10 mA cm−2 by applying just 1.405 V across the two electrodes. Hence, the porous mesh‐like FeCo2S4 nanosheet arrays on Ni foam are promising electrode materials for supercapacitor application and water splitting.