Construction of CuO/Cu2O@CoO core shell nanowire arrays for high-performance supercapacitors

• The in situ grown CuO/Cu2O substrates by anodic oxidation have low resistance.
• The introduction of CoO can enormously enhance the capacitance performance.
• Rough surfaces provide sufficient electroactive sites for electrons shuttle.
• The shell alleviates strain during electron transfer, improving stability.

In this paper, we reported construction of CuO/Cu2O@CoO core-shell nanowire arrays by combining a chemical deposition method and post-thermal annealing process on Cu foil without any binders and conductive additives. The nanowire arrays were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM) and energy dispersive X-ray spectroscopy (EDX) techniques. The determination results indicate that the nanowire arrays are distinct CuO/Cu2O nanowire core decorated with branched CoO nanosheet shells. In addition, the as-obtained nanowire arrays demonstrate outstanding areal capacitance of 280 mF cm− 2 at a current density of 1 mA cm− 2 as well as superior cycling stability which remains 90.7% of initial capacitance after 3000 cycles. The facile and cost-effective synthesis integrated with the robust electrochemical performances suggests that the CuO/Cu2O@CoO core-shell nanowire arrays are expected to be promising candidate electrodes for high-performance supercapacitor and other energy storage applications.