Nanostructured Co3O4 electrodes for supercapacitor applications from plasma spray technique

Among different transition metal oxides cobalt oxide (Co3O4) has attracted considerable attention for supercapacitor applications because of its superior electrochemical characteristics at relatively low cost. Nanostructured Co3O4 electrodes are usually prepared from powders using sol–gel and hydrothermal techniques, which require multi-step procedures and longer processing times. Here, we report synthesis and characterization of Co3O4 supercapacitor electrode films deposited directly on current collectors via a single step solution precursor plasma spray route. In this approach, an aqueous solution containing cobalt acetate is axially fed into plasma plume to produce nanoparticulates of Co3O4 via accelerated thermo-chemical conversion process, which are eventually deposited on a current collector substrate. Thus, developed Co3O4 electrodes showed nano particulate structure with porosity. The phase structure and crystallinity of Co3O4 electrode films were analyzed by X-ray diffraction and differential scanning calorimetry–thermogravimetry (DSC–TGA) studies. Electrochemical performance of these coatings showed a specific capacitance of ∼162 F g−1 with a retention capacity of 72.2% after 1000 cycles for a specific current rate of 2.75 A g−1 in 6 M KOH electrolyte.

► Nanostructured and porous Co3O4 electrodes for supercapacitors.
► Flexible and binder free electrodes for high temperature supercapacitor applications.
► Electrodes developed, for the first time, by plasma spray process.
► Rapid processing of supercapacitors in a single step process using economical industrial scale technology.