Preparation of NiCo-LDH composite materials derived from NiCo-MOF by alkaline etching for high performance supercapacitor

An innovative preparation approach was utilized to prepare bimetallic nanohybrid arrays of NiCo-LDH onto nickel foam through a hydrothermal technique. Then, 2,5-Dihydroxyterephthalic acid ligands were engaged to synthesize NiCo-MOF via a solvothermal method. Subsequently, an alkaline etching-induced technique transformed the bimetallic MOF back into LDH (designated as Et–NiCo-LDH), yielding a bimetallic hydroxide characterized by a denser nanohybrid array and a more abundant pore structure, thereby demonstrating exceptional specific capacitance. The resultant material exhibited a remarkable specific capacitance of 22.39 F cm⁻² at a current density of 2 mA cm⁻² (about 1194.16 F g⁻¹ at 1 A g⁻¹.The loading capacity is 12 mg per square centimeter). After enduring 5000 galvanostatic charge-discharge cycles at a current density of 15 mA cm⁻², the material maintained 83.6 % of its initial capacity. Furthermore, when assembled into an asymmetric supercapacitor device with the as-synthesized Et–NiCo-LDH@NF composites serving as the positive electrode and activated carbon (AC) as the negative electrode, the device demonstrated an energy density of 671.42 Wh m⁻² and a power density of 1399.99 W m⁻². Additionally, at a mass loading of 1 A g⁻¹, the energy density and power density were recorded as 45.04 Wh kg⁻¹ and 350.37 W kg⁻¹, respectively, with a mass loading of 12 mg cm⁻². A capacity retention rate of 85.6 % was achieved after 5000 cycles. This study offers a straightforward method for producing uniform and dense bimetallic nanohybrid arrays tailored for applications in the capacitor field.