Successive Ionic Layer Adsorption and Reaction (SILAR) Synthesis of CoMoO₄ Nanostructures for High–Performance Supercapacitors: Structural and Electrochemical Characterization

Supercapacitors have emerged as promising energy storage devices due to their high power density and rapid charge-discharge capabilities. In this work, we report the facile and scalable synthesis of cobalt molybdate (CoMoO4) nanostructures using the Successive Ionic Layer Adsorption and Reaction (SILAR) method, an eco-friendly and cost-effective deposition technique. The structural, morphological, and electrochemical properties of as-deposited CoMoO4 on Ni-foam and its annealed counterpart (CM300, treated at 300°C for 4 hours) were systematically investigated. X-ray diffraction (XRD) confirmed the crystalline phase of CoMoO4, while scanning electron microscopy (SEM) revealed a nanostructured morphology that enhances active surface area for electrochemical reactions. Electrochemical evaluations, including cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) measurements in a 2 M KOH electrolyte, demonstrated outstanding supercapacitive performance. The CM300 electrode exhibited a remarkable specific capacitance of 1126 F g⁻¹ at 5 mA cm⁻², along with a high energy density of 56.34 Wh kg⁻¹ and a power density of 340.9 W kg⁻¹. The enhanced performance is attributed to the improved crystallinity and porous nanostructure of the annealed CoMoO4, facilitating efficient ion diffusion and charge transfer. Additionally, the binder-free electrode fabrication on Ni-foam enhances mechanical stability and practical applicability for supercapacitor devices. This study highlights the potential of SILAR-synthesized CoMoO4 as a high-performance electrode material for next-generation supercapacitors, offering a sustainable and scalable approach for energy storage applications.