Co3O4 nanowire modified with carbon nanotubes to be used as improved asymmetric supercapacitor electrode

Abstract

Co3O4 itself suffers from drawbacks such as poor conductivity and a low active site density, significantly limiting its application in capacitors. To address this issue, this study employs a one-step hydrothermal method to incorporate carbon nanotubes (CNTs) into Co3O4, resulting in the fabrication of Co3O4/CNTs composite nanomaterials. In comparison to the pristine Co3O4 material, this composite exhibits a 69.7 % improvement in specific capacitance. When Co3O4/CNTs and activated carbon (AC) are assembled into asymmetric capacitors, an impressive energy density of 58.46 Wh Kg−1 (461.52 W Kg−1) is achievable at room temperature, with a capacitance retention rate of 83.2 % observed after 65,000 charge-discharge cycles. The addition of CNTs made the Co3O4 nanowire clusters and their binding with nickel foam more tightly, increasing the conductivity of the material and exposing more active sites while improving stability. This study offers valuable insights for further advancements and practical applications of electrode materials in supercapacitors.