Probing the electrochemical properties of NiMn2O4 nanoparticles as prominent electrode materials for supercapacitor applications

Abstract

NiMn2O4 (NMO) powders have been prepared by facile sol-gel route, and the effect of annealing temperature and the concentration of KOH electrolyte on its electrochemical performance has been investigated. The electrochemical performance of the NMO electrodes is tested via a three electrode arrangement in KOH electrolyte. The NMO electrode (NMO1) prepared from the powder synthesized at a temperature of 500 degrees C with an approximate crystallite size of 10 nm exhibits maximum specific capacitance of 571 Fg(-1) at a scan rate of 5 mVs(-1) in 1 M KOH electrolyte. The specific capacitance of the NMO1 electrode is found to be improved from 571 Fg(-1) in 1 M KOH to 762 Fg(-1) in 6 M KOH electrolyte. The improvement in the specific capacitance of the NMO1 working electrode in 6 M KOH electrolyte can be attributed to good electrochemical utilization and an effective charge storage mechanism.