Rational design of Cu-doped Co3O4@carbon nanocomposite and agriculture crop-waste derived activated carbon for high-performance hybrid supercapacitors

Development of structurally stable transition metal-oxides and cost-effective biomass-based carbon materials have attracted considerable attention in the fabrication of hybrid supercapacitors. In this work, we designed spinal copper-doped cobalt oxide (Cu-Co3O4 ) nanoboxes decorated functionalized-carbon nanotubes (f-CNTs) as hybrid redox-type material and agriculture crop-waste derived mesoporous activated carbon as capacitive-type electrode for high-performance hybrid supercapacitors. Structural properties reveal that the Cu-Co3O4 has a cubic spinel structure and Raman spectra results confirm the presence of f-CNTs. The hybrid composite material demonstrates superior redox behavior with excellent structural durability. The hybrid electrodes exhibit maximum specific capacity of 130.7 mAh g−1 at 0.5 A g−1 with 86.7 % capacitance retention over 10,000 cycles. Besides, the crop waste-derived activated carbon demonstrates high surface area (1549 m2g-1), mesoporous characteristics and excellent capacitive behavior. The high voltage hybrid supercapacitor is further fabricated with Cu-Co3O4 @F-CNTs as battery-type and biomass-derived activated carbon as capacitive-type electrodes, which demonstrate high energy density of 30.8 Wh kg−1 at 5972 W kg -1 power density. The augmented results indicate that the hybrid composites with biomass-derived carbon materials pave the way for design of eco-friendly energy storage applications.