Facile synthesis of spinel nickel–manganese cobaltite nanoparticles with high rate capability and excellent cycling performance for supercapacitor electrodes

Nickel- and manganese-based spinel compounds have emerged as important candidates for electrochemical energy storage. In this study, a spinel nickel–manganese cobaltite (s-NMC) material was synthesized by facile hydrothermal/calcination route and the material exhibited remarkable pseudocapacitive behavior performance. The synthesized s-NMC material had a specific capacitance of 418.3 F g−1 at a scan rate of 10 mV s−1 (216.2 F g−1 at a current density of 1 A g−1) and retained 95 of its specific capacitance after 5000 charge–discharge cycles at a current density of 2 A g−1. These excellent electrochemical properties are attributed to the simultaneous presence of three transition metals in the s-NMC material. The asymmetric supercapacitor device using s-NMC delivered a maximum specific energy density of 16.58 Wh kg−1 at a specific power density of 825 W kg−1 and maintains of ∼97 specific capacitance after 2000 cycles at a current density of 2 A g−1. This study highlights that the diversification of transition metals in spinel-based metal oxides is an effective approach to enhance the electrochemical performances in resulting compound materials. Graphical abstract: Figure not available: see fulltext. © 2023, The Author(s), under exclusive licence to Springer Nature B.V.