Study of Asymmetric Hybrid Supercapacitor using Carbon and Metal Oxides as Electrode Materials

Objectives: In this paper, we report the fabrication and analysis of twelve (12) different supercapacitors using metal oxide electrode as cathode and carbon electrode as anode. Methods: The metal oxide electrode was prepared using Solgel method by combining any two (2) out of this (3) transition metals Nickle (Ni), Cobalt (Co) and Manganese (Mn) to see which will produce the highest specific capacitance. The work reported here differs from other works, because the degree of inversion was varied by a factor of 0.2 to see the effect it will have on the performance. The morphology and crystal structure of each cell was studied using Scanning Electrode Microscope (SEM), X-Ray Diffraction (XRD), while the performance was tested using Cyclic Voltammetry (CV) and galvanometric analysis. Findings: The obtained CV plots were used to calculate specific capacitance of each cell and comparison of results was made with other supercapacitors. From the SEM images it was observed that sample 11 had large pores this allowed easy diffusion of electrolyte, whereas sample 12 had a non-uniform crystalline image with hairy surface which made it difficult for electrolyte to pass. The highest specific capacitance value obtained was 78 Fg^-1 for sample 11 (Mn_0.6Co_0.4) and the minimum value obtained was 5 Fg^-1 (Mn_0.8Co_0.2) for sample 12. The use of different metal oxides with different inversion factor made it possible to see the contribution of each metal oxide and by combining two out of three made it possible to reduce cost. Applications: With the invention of supercapacitors it made it easy to incorporate for application purpose due to its unique qualities like high power density and good cycle life. It is currently being used in hybrid electrical vehicle, power quality improvement.