Bulk synthesis of chemically activated carbon and cobalt oxide nanocomposites as supercapacitor electrodes

A simple and inexpensive method was presented to prepare a bulk product of chemically activated carbon (AC) and cobalt oxide (Co₃O₄) nanocomposites (AC/Co₃O₄) with different weight ratios by a solid-state reaction, which can be used as electrode materials for supercapacitor applications. The microstructure, porosity, and surface chemical properties of the prepared samples were studied in the context of their different electrochemical properties. The results showed that the electrode prepared by mixing the micrometer-sized porous structure AC with 30 wt% Co₃O₄ nanoparticles has a maximum specific capacitance of 435.72 F/g at a current density of 1 A/g in 6 M KOH electrolyte and excellent capacitance retention of 97.3% after 5000 galvanostatic charge/discharge cycles. In addition, the AC/Co₃O₄ 30 wt% asymmetric supercapacitor can deliver an energy density of 4.71 Wh/kg and a power density of 487.06 W/kg at a current density of 1 A/g. Therefore, the AC/Co₃O₄ 30 wt% nanocomposite materials represent a promising pseudocapacitive material for the next generation of electrochemical and energy storage applications.