Hydrothermal synthesis of mesoporous NiMnO3 nanostructures for supercapacitor application: Effect of electrolyte

•NiMnO3 (NMO) nanostructures are prepared by the hydrothermal method.•NMONickel foam (NF) electrode showed a specific capacitance of 435 Fg-1 in 1 M KOH.•NMONF electrode displayed 100% capacitance retention for 2000 cycles in 1 M KOH. In recent days, energy storage devices like supercapacitors are gaining increasing interest. However, the real challenge of getting high specific capacitance with significant mechanical stability and high energy density at an affordable cost for the supercapacitors based on mixed transition metal oxides continues. Herein, mesoporous NiMnO3 (NMO) nanostructures have been prepared by the hydrothermal method. Electrochemical performance of the NMONickel foam (NF) electrode is investigated by cyclic voltammetry at various scan rates of 5–100 mVs−1, galvanostatic charge-discharge at various current densities of 3–5 mAcm−2, and electrochemical impedance spectroscopy over a frequency range of 100 Hz to 100 kHz in 1 M KOH, 1 M NaOH, and 1 M Na2SO4 electrolytes. The NMONF working electrode displayed a high specific capacitance of 435 Fg−1 at a scan rate of 5 mVs−1 and 100% cyclic stability for 2000 cycles, in 1 M KOH electrolyte. The determined values of specific energy, specific power, and coulombic efficiency for NMO- NF electrodes are 11.13 Whkg−1, 198.52 Wkg−1, and 98.1%, respectively. [Display omitted]