Enhanced electrochemical performance of NiMn₂O₄ electrode synthesized via sol–gel technique for supercapacitor applications

Here, we report the synthesis of NiMn₂O₄ nanostructures using sol–gel technique. The synthesized NiMn₂O₄ electrode material exhibited a high BET surface area ~ 97.4 m²/g, contributing significantly to its enhanced electrochemical performance in supercapacitor applications The charge storage capability and cycle stability of the resulting NiMn₂O₄ nanostructures were investigated using cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS) in a 1.0 M KOH electrolyte. These electrochemical techniques revealed that the as-prepared NiMn₂O₄ nanostructures revealed a significantly enhanced specific capacitance of 1270 F g⁻¹ at a current density of 0.3 A g⁻¹, indicating their excellent charge storage performance. Furthermore, the NiMn₂O₄ electrode demonstrates remarkable cycling stability, retaining 94% of its initial capacitance after 5000 cycles and a coulombic efficiency of 98% at a current density of 0.7 A g⁻¹. For supercapacitor application, the NiMn₂O₄ material delivers a high energy density ~ 47 Wh kg⁻¹ along with power density ~ 5404 W kg⁻¹. The exceptional storage properties of the NiMn₂O₄ electrode make it an ideal candidate for energy storage applications.