Hydrothermal growth of Co3O4 nanoparticles on nickel foam for high-performance pseudocapacitive supercapacitors: Effect of cobalt loading

Advancing supercapacitor technologies for renewable energy storage relies heavily on the development of high-performance electrode materials. Herein, cobalt oxide (Co 3 O 4 ) nanoparticles were in-situ grown on nickel foam (NF) substrates employing a binder-free hydrothermal method with varying cobalt precursor concentrations (Cox@NF, x = 0–32 mmol), to explore the effect of Co loading on the supercapacitor’s electrochemical efficiency. Complementary characterization studies revealed the formation of a cubic spinel Co 3 O 4 phase in the form of spherical nanoparticles uniformly decorating the NF surface at an optimal Co concentration of 16 mmol. This structure exhibits favorable textural and porous properties, enhanced Co 2 + /Co 3+ redox activity, and a high concentration of oxygen vacancies, all of which contribute to improved pseudocapacitive behavior. The Co16@NF electrode demonstrated optimal electrochemical performance, combining a high areal capacitance of ∼4162 mF cm −2 at 5 mA cm −2 and energy density of ∼120 Wh kg −1 at a power density of ∼25 kW kg −1 . An asymmetric Co16@NF//AC hybrid supercapacitor setup confirmed its viability in real-world applications. These findings underscore the significance of compositional tuning and nanostructure optimization in achieving high-performance Co 3 O 4 -based electrodes for next-generation energy storage devices. • Hydrothermal growth of Co 3 O 4 nanostructures on nickel foam for supercapacitor applications. • Impact of Co loading on electrochemical efficiency. • Co16@NF exhibits superior capacitance, offering 4162 mF cm −2 at 5 mA cm −2 . • Co16@NF achieved an optimal balance between surface coverage, oxidation state, and porosity.