Nanoengineering of CoFe-LDH@Ni(OH)2 for supercapacitor and water splitting applications.

The self-supported Co–Fe LDH@Ni(OH)₂ material is successfully prepared on a foam nickel substrate through two hydrothermal processes. The phase structure and microstructure of the electrode material are investigated through X-ray diffractometer (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), and transmission electron microscope (TEM) analyses. The electrode materials undergo electrochemical and electrocatalytic tests using an electrochemical workstation. This study demonstrates that the specific capacitance of the Co–Fe LDH@Ni(OH)₂ is 2626 mF cm⁻² at 1 mA cm⁻². Supercapacitors made of LDH@Ni(OH)₂ electrode material operate exceptionally well. Both the power density and the energy density are 0.755 mW cm⁻² and 32.5 μWh cm⁻², respectively. As a catalyst material for electrochemical splitting of water, CoFe-LDH@Ni(OH)₂ exhibits distinguished electrocatalytic properties. The overpotential is 242 mV at 50 mA cm⁻² in HER, while that is 149 mV at 20 mA cm⁻² in OER. Meanwhile, the CoFe-LDH@Ni(OH)₂ electrocatalytic material also performs extremely well in the overall water electrolysis testing. The voltage is 1.65 V at 25 mA cm⁻², which shows strong cyclic stability. The material provides a reliable guarantee for sustained and stable operation in various application scenarios. [ABSTRACT FROM AUTHOR]