Hierarchical spinel NiMn2O4 nanostructures anchored on 3-D nickel foam as stable and high-performance supercapacitor electrode material

Abstract

A simple hydrothermal route has been used to synthesize NiMn2O4 nanostructures (NSs) on nickel foam. The electrochemical investigation shows how annealing temperature affects its supercapacitive properties. The NMO@500-Ni-foam electrode shows a high specific capacitance of 930 Fg  1 at a constant scan rate of 5 mVs  1 in 1 M KOH electrolyte. Additionally, the corresponding symmetric supercapacitor device (SSCs) has a superior cyclic span with 93.7 % capacitance retention even after 5000 cycles, excellent electrochemical performance with a specific capacitance of 72.9 Fg  1, specific energy of 11 Whkg  1, and specific power of 857 Wkg  1. The exceptional results suggest that NiMn2O4 grown on Ni-foam might be a promising candidate for electrochemical energy storage applications.