The evaluation of the electrochemical properties of Co3O4 nanopowders synthesized by autocombustion and sol–gel methods

The present investigation involves two synthesis methods, autocombustion (Co3O4-AC) and sol–gel (Co3O4-SG), for producing nearly spherical-shaped and polygonal shaped nanomaterials of spinel cobalt oxide (Co3O4) respectively as electrode materials. TEM image analysis unveiled distinct particle morphologies for the two samples. The Co3O4-AC particles exhibited a nearly spherical shape, whereas the Co3O4-SG particles displayed a polygonal shape. The phase purity of the Co3O4 samples were confirmed via XRD patterns analysis and the crystallite size was calculated to be 44 nm for Co3O4-AC and 36 nm for Co3O4-SG. The surface area, estimated via BET experiments, of Co3O4-AC was found to be 15 m2/g, while Co3O4-SG exhibited a slightly lower surface area of 11 m2/g. Co3O4-AC exhibited a higher specific capacitance (Cs) of 162 F/g at 0.25 A/g, indicating its superior energy storage capability. On the other hand, Co3O4-SG shows a Cs of 98 F/g, indicating slightly lower performance compared to Co3O4-AC. Both nanomaterials exhibited better stability, with more than 85% capacity retention after 5000 charge–discharge cycles.