Electrochemical performance of complex oxides of manganese incorporated vanadium pentoxide-based electrode materials for energy storage applications

Abstract A series of manganese-substituted V 2- x Mn x O 5-δ compounds (0.05 ≤ x ≤ 0.25) is synthesized via the solid-state reaction method. The chemical composition and vibrational characteristics of the samples were probed using X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared (FTIR) spectroscopy, respectively. XPS analysis confirmed the presence of Mn 3+ and Mn 4+ ions, with the symmetric Mn 2p 1 / 2 and Mn 2p 3 / 2 peaks showing increased intensity ratios as manganese concentration rises. FTIR spectra displayed distinct vibrational modes of V 2 O 5 and MnV 2 O 6 phases, validating the incorporation of Mn ions in the lattice structure. Electrochemical performance in a 1 M KOH electrolyte showed a specific capacitance of 277 F/g at a 5 mV/s scan rate via cyclic voltammetry, corroborated by 286 F/g at a 0.5 A/g current density from galvanostatic charge-discharge tests. Among the prepared samples, the electrode with x = 0.20 demonstrated the highest capacitance, retained 91 % of specific capacitance and 99 % of coulombic efficiency after 5,000 charge-discharge cycles. The electrode achieved an energy density of 25.4 Wh/kg and a power density of 180 W/kg, reflecting superior supercapacitive properties. The synergy of manganese substitution and the cost-effective synthesis approach makes V 2- x Mn x O 5-δ a promising material for supercapacitor electrodes, supporting the advancements of sustainable energy storage technologies.