Hierarchical Cu2O@NiCoMn-OH on copper wire for high-performance flexible supercapacitors

Abstract

Extensive efforts have been made to develop active materials with high energy density to meet the current demand for high-performance energy storage devices. In this study, we successfully achieved a hierarchical structure combining copper oxide and NiCoMn ternary metal hydroxide through a two-step electrochemical deposition process on the surface of a copper wire (CW) current collector. This unique structure consists of an internal honeycomb-like Cu₂O framework and external NiCoMn-OH nanosheets. The resulting electrode exhibits enhanced electrochemical performance due to the synergistic effect between these two active materials, demonstrating a high specific capacitance of 956 F g⁻¹ at a current density of 4 A g⁻¹. Moreover, the as-fabricated symmetric flexible supercapacitor exhibited an impressive specific capacitance of 11.06 F cm⁻³ at a current density of 0.3 A cm⁻³, along with an excellent capacitance retention rate of up to 93.26 % after 6000 cycles. Moreover, the device demonstrated a remarkable energy density of 0.18 mWh cm⁻² when operated at a power density of 11.77 mW cm⁻².