Cost-effective preparation of ZnO-CNT nanocomposite-based electrode for supercapacitor application

Abstract

The increasing energy demand has attracted researchers to develop a cost-effective electrode material for energy storage applications. Zinc Oxide (ZnO) and Carbon nanotubes (CNT) are among the most explored electrode materials for such applications. However, the reported literature doesn’t have a cost-effective approach. The present work has reported the cost-effective synthesis of ZnO and ZnO-CNT nanocomposite via hydrothermal and simple blending methods respectively. The structural and morphological properties were studied using XRD and FESEM. It was found that the diameter of CNT was ∼ 22 nm and the ZnO nanoparticles were spherical in shape, having an average particle size of ∼ 13 nm. Further, graphite rod was used as electrode substrate, which was optimized to study the electrochemical behavior of active materials in 6 M KOH electrolytic solution. The CV and GCD studies revealed that with the decrease in scan rate/current density, the value of specific capacitance increased. The maximum value of specific capacitance achieved was 67.5F/g at 1 A/g current density. In addition, the ZnO-CNT nanocomposite electrode showed cyclic stability up to 16,000 cycles. From EIS spectra, it has been found that the ZnO-CNT nanocomposite had a low bulk resistance (Rs) value i.e., 2.6 Ω. Thus, the electrochemical performance of ZnO-CNT nanocomposite inferred its high potential for future energy storage applications.