Investigation and Comparative Studies on Charge Storage Performance in Nanostructured RuO2, NiO and Co3O4 Nanoparticles for High Dense Energy Storage

Increasing energy requirement and over energy consumption and further upgrading of energy transfer and storage mechanisms are the critical problem. The supercapacitor is a good candidate for applications requiring high power delivery or uptake. Metal oxides can be effective electrode materials for energy storage devices due to their multiple oxidation states, high theoretical specific capacitance, wide potential window and eco-friendliness. In this connection, here report that electrodes made of notable nanosized transition metal oxides such as Ruthenium oxide (RuO₂), Nickel oxide (NiO) and Cobalt oxide (Co₃O₄) were prepared by simple hydrothermal route and the prepared samples were confirmed through structural, vibrational, morphological, and elemental composition analysis. The modified working electrodes were then examined for electrochemical behavior, including CV, GCD, and EIS studies, using a 1 M KOH electrolyte solution after successive coating of the working material on empty Ni foil. Among them, RuO₂ has high integral area, a low sweep rate and remarkable specific capacitance value of 447.1 Fg^-1 at 5 mVs^-1 in CV analysis. In addition, the GCD curve has good charge-discharge cyclic stability with a maximum specific capacitance of 412.1 Fg^-1 at 0.5 Ag^-1 compared to NiO and Co₃O₄. RuO₂ has long charge-discharge stability and only 6.8% loss in capacitive retention compared to the other systems, NiO (11.2%) and Co₃O₄ (9.3%), even after 10,000 cycles. We except that use of nanosized metal oxide electrodes to enhance electrochemical activity will lead to further improvement in the supercapacitors.