Core–Shell Nanostructured Hybrid of Nickel Hydroxide Supported on Copper Hydroxide Nanorod Arrays Used as Advanced Supercapacitors with High Efficiency and Ultraperformance

Abstract The fascinating search for ultraefficient and high‐powered supercapacitors has stimulated continuous exploration of diverse energy storage materials like transition metal hydroxides with core–shell structure. Thus in this paper, a novel core–shell hybrid electrode material of nickel hydroxide (Ni(OH)₂) supported on copper hydroxide nanorod arrays (Cu(OH)₂ NAs), which is constructed on copper foam as the substrate by an in situ chemical oxidation reaction accompanied by chemical bath deposition, is reported. As a result, it is found that the pre‐fabricated Cu(OH)₂@Ni(OH)₂ electrode has a remarkable areal capacitance of 9.27 F cm⁻² and good cycling performance (retains 92.38% after 6000 cycles) compared to its counterpart Cu(OH)₂ nanorods (88.57%). Additionally, the Cu(OH)₂@Ni(OH)₂ material, as a positive electrode, can also be used to assemble a hybrid supercapacitor (HSC) while activated carbon is chosen as the negative electrode. As a result, the constructed HSC device with the desired working voltage of 0–1.5 V can light up the light‐emitting diode indicator, proving the potential practicability of the pre‐fabricated HSC device.