Hydrothermal synthesis of CuMn₂O₄ spinel-coated stainless steel mesh as a supercapacitor electrode

CuMn₂O₄ with spinel structure was synthesized on a flexible stainless steel mesh by a one-pot hydrothermal method and evaluated as a supercapacitor electrode. The stainless steel mesh is used as an alternative to nickel foam. X-ray diffraction analysis was used to determine the crystal structure, revealing the presence of a major cubic spinel phase. The hydrothermal technique resulted in an average crystallite size of 12.174 nm. Functional groups present in the samples were confirmed using Fourier transform infrared spectroscopy. The results showed two bands, at 760.62 cm⁻¹ and 555.64 cm⁻¹, relative to stretching vibrations of the tetrahedral and octahedral groups, respectively. Scanning electron microscopy analysis shows a surface microstructure in the shape of flat sheets. Energy-dispersive X-ray spectroscopy analysis displays the material’s elemental composition, with atomic ratios of 0.8 for Cu:Mn and 0.27 for Cu:O. Cyclic voltammetry and electrochemical impedance spectroscopy were implemented to assess the electrochemical performance of the electrode. The as-obtained CuMn₂O₄ exhibited excellent electrochemical properties. It delivered a low electrolyte solution resistance R_s (5.5 Ω) and a high specific capacity of 1169.3 F/g for 1.15 × 10^–3 g of active material at a low scan rate of 1 mV/s.