Hierarchical CuAl-layered double hydroxide/CoWO4 nanocomposites with enhanced efficiency for use in supercapacitors with long cycling stability

Abstract

A novel nanocomposite containing CuAl-layered double hydroxide (CuAl-LDH) nanoflowers with ultrathin petals and cobalt tungstate nanostars (CuAl-LDH/CoWO₄) was employed to devise a high-performance supercapacitor. In the proposed composite, a CoWO₄ binary metal oxide was used to generate more electroactive sites, enhance the conductivity of the CuAl-LDH nanoflowers, and prevent their aggregation, therefore promoting the electrochemical activity of the resultant electrode. A three-electrode system was adopted to investigate the electrochemical performance of the nanocomposite and assess its potential for application as an electrode material in supercapacitor devices. The nanocomposite presented an outstanding specific capacitance at a current density of 5 A g⁻¹ (i.e., 675 F g⁻¹), exhibiting noticeable cycling stability over 5000 continuous cycles. Also, application of the nanocomposite in the fabrication of a two-electrode asymmetric supercapacitor provided 35.87 W h kg⁻¹ maximum energy density, 10 188 W kg⁻¹ power density and high cycling stability. So, the fabricated supercapacitor maintained 97.1% of its initial capacitance after 5000 cycles and powered a red light-emitting diode for a considerable period of time. Based on electrochemical measurements, it was found that the specific morphology of the CuAl-LDH/CoWO₄ nanocomposite helps it to provide many ion/charge transportation paths, a high electrochemically active surface area and, therefore, a high level of supercapacitance. In general, the findings of this study show that the CuAl-LDH/CoWO₄ nanocomposite is an appropriate electrode material for the practical storage of energy.