Al-doped ZnO@CuO nanoflower/nanorod heterostructures on CNTs as high-performance supercapacitor electrodes in redox-supporting electrolytes

Abstract

Developing high-performance supercapacitor (SC) electrodes requires materials with optimized electrical conductivity, surface area, and modifiable morphology. This work presents a facile hydrothermal synthesis of carbon nanotubes (CNTs)-supported Al-doped ZnO@CuO composite. Structural characterization reveals that Al doping and CuO incorporation can transform ZnO nanoflakes into nanorod/nanoflower heterostructures. The electrochemical analysis of the ternary composite in a mixed electrolyte, containing 2 M KOH, 0.2 M potassium ferrocyanide (KFC), and 0.2 M potassium iodide (KI) exhibits a specific capacitance of 1860 F/g at 1 mV/s. The fabricated asymmetric supercapacitor (ASC) yields an energy density of 36 Wh/kg, a power density of 3502.8 W/kg at 30 A/g, and 106 % capacitance retention after 5000 continuous charge-discharge cycles. These findings suggest that AZOCC has excellent potential for SC electrodes and demonstrate the feasibility of using KI as an electrolyte support for enhanced electrochemical performance. © 2024 Elsevier Ltd