Enhancing the Performance of Cobalt-based Oxide Electrode Material for Asymmetric Supercapacitor Devices

Supercapattery is an energy storage device which shows high power and energy densities compared to supercapacitors and batteries. A simple and cost-effective sol-gel method was used to synthesize the aluminium-doped cobalt oxide (Al-Co3O4). The structural, morphological and composition analyses were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). Further, Brunauer-Emmett-Teller (BET) calculations were performed, which showed an enhancement in surface area. The specific capacity of the Al-doped sample was increased up to 708 C/g compared to the reference sample (Co3O4=420 C/g). A supercapattery device was designed by using the activated carbon as a negative electrode and the Al-Co3O4 as the positive electrode in two electrode assemblies. The estimated value of the specific capacity of Al-Co3O4 was 189 C/g. Furthermore, the obtained energy and power density values were 42 Wh/kg and 2080 W/kg, respectively. To investigate the stability, this device was subjected to 5000 charging/discharging cycles that maintained 90 % of its initial capacity. Our findings provide a foundation for improving the performance of energy storage devices.