Engineering Hierarchical Nickel Cobalt Metal–Organic Frameworks Through Metal Ion Modulation for High‐Performance Hybrid Aqueous Supercapacitor Devices

Recent advances on metal–organic framework (MOF)‐based electrodes have led to significant breakthroughs in the energy storage device sector. In this study, we explored the binder and conducting carbon free synthesis of nickel‐cobalt MOF electrodes on nickel foam substrate via the simple successive ionic layer adsorption and reaction (SILAR) technique. The concentration of Ni and Co precursor [molar ratio] is systematically varied to obtain a series of NiCo‐MOF‐based electrodes. An excellent charge storage performance for NCM3 (Ni:Co, 1:1) electrode was revealed in a three‐electrode system, which can be attributed to homogeneous interconnected platelet‐like morphology. The NCM3 electrode exhibited a specific capacity (Csp) of 934 C g ⁻¹ at 2 mA cm ⁻² current density. To show the practical applicability, a hybrid aqueous supercapacitor device (HASD) with a widened potential window was fabricated, comprising NCM3 as the positive electrode and reduced graphene oxide (rGO) as the negative electrode (NCM3//KOH//rGO). HASD delivered remarkable specific capacitance (Sc) of 128 F g ⁻¹ and maximum specific energy (SE) of 45.58 Wh kg ⁻¹ at 2 mA cm ⁻² . The highest specific power (SP) of 3840 W kg ⁻¹ was achieved at 6 mA cm ⁻² . Thus, SILAR‐based approach presents a promising route for the synthesis of high‐performance NiCo‐MOF‐based electrodes.