3D hierarchical ZnCo₂S₄@Ni(OH)₂ nanowire arrays with excellent flexible energy storage and electrocatalytic performance

It is essential for energy storage and conversion systems to construct electrodes and electrocatalysts with superior performance. In this work, ZnCo₂S₄@Ni(OH)₂ nanowire arrays are synthesized on nickel foam by hydrothermal methods. As a supercapacitor electrode, the ZnCo₂S₄@Ni(OH)₂ structure exhibits a specific capacitance of 1,263.0C g^-1 at 1 A g^-1. The as-fabricated ZnCo₂S₄@Ni(OH)₂//active carbon device can achieve a maximum energy density of 115.4 Wh kg^-1 at a power density of 5,400 W kg^-1. As electrocatalysts, the ZnCo₂S₄@Ni(OH)₂ structure delivers outstanding performance for oxygen evolution reaction (an overpotential of 256.3 mV at 50 mA cm^-2), hydrogen evolution reaction (141.7 mV at 10 mA cm^-2), overall water splitting (the cell voltage of 1.53 V at 50 mA cm^-2), and a high stability for 13 h.