Zn-Doped Nico-Ldh Nanoflakes Grown In-Situ on Cuo/Cu as an Electrode for Coaxial Flexible Asymmetric Supercapacitor

Abstract

The design of electrode materials with superior nanostructures plays a crucial role in the performance enhancement of supercapacitors. Preparation of excellent electrode materials can be achieved through methods such as compositing and doping. In this paper, CuO nanowires were grown on flexible Cu wire firstly, which increases the specific surface area of the Cu wire and optimizes the intrinsic electrochemical performance. CuO@NiCoZn-LDH composites were prepared by the hydrothermal method, with Zn successfully doped into NiCo-LDH by replacing the position of Ni or Co in the LDH layers. The morphology, structure and electrochemical properties of the electrode materials with and without Zn doping were compared. The results reveal that the Zn doping enlarged the nanostructure dimensions of NiCo-LDH and increased the specific surface area and active sites, thereby enhancing the electrochemical performance. Further, a coaxial flexible supercapacitor was assembled using CuO@NiCoZn-LDH prepared under optimal condition as the positive electrode and activated carbon paper (ACP) as the negative electrode. This supercapacitor demonstrated an energy density of 35.6 μWh cm−2 at a power density of 1.6 mW cm−2. After 8000 charge-discharge cycles, the specific capacitance remained at 75.67%. This work provides insights for designing flexible energy storage devices with excellent electrochemical performance.

Keywords: Zn-doped, NiCo-LDH, Flexible, Supercapacitor