Redox-active Copper Manganese Selenides Embedded over CNTs as an Electrode material for hybrid supercapacitors

Abstract

Transition metal selenides have recently become a more favorable material for energy storage applications owing to their exceptional electrochemical activity, high theoretical capacities, conductivity, and non-toxic nature. Herein, we have synthesized different compositions of copper and manganese-based selenide nanocomposites embedded over multi-wall carbon nanotubes (MWCNTs) through hydrothermal technique. The proper synthesis of the materials has been validated through different morphological and structural characterizations. All the electrodes in a three-electrode assembly were tested and the Cu0.50Mn0.50Se2/MWCNTs sample displays outstanding electrochemical performance. The optimum sample displayed exceptional specific capacities of 1437.4 C/g at 5 mV/s (and 1365.3 C/g at 1 A/g), which exceeded the reference sample by 3 to 6 times, respectively. Furthermore, the Cu0.50Mn0.50Se/MWCNTs || AC supercapattery device was fabricated which resulted in energy density (Ed) and power density (Pd) of 68.3 Wh/kg and 8.5 kW/kg, respectively. The device was also tested for 8000 cycles, maintaining 82.3 % of its preliminary capacity and excellent Coulombic efficiency of 99.5 %. The hybrid nature was confirmed through Power’s law and Dunn’s model of Cu0.50Mn0.50Se/MWCNTs || AC device. This work demonstrates that selenide-based nanocomposites have the potential to be considered as battery-grade material in hybrid supercapacitors.