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

The present investigation involves two synthesis methods, autocombustion (Co 3 O 4 -AC) and sol–gel (Co 3 O 4 -SG), for producing nearly spherical-shaped and polygonal shaped nanomaterials of spinel cobalt oxide (Co 3 O 4 ) respectively as electrode materials. TEM image analysis unveiled distinct particle morphologies for the two samples. The Co 3 O 4 -AC particles exhibited a nearly spherical shape, whereas the Co 3 O 4 -SG particles displayed a polygonal shape. The phase purity of the Co 3 O 4 samples were confirmed via XRD patterns analysis and the crystallite size was calculated to be 44 nm for Co 3 O 4 -AC and 36 nm for Co 3 O 4 -SG. The surface area, estimated via BET experiments, of Co 3 O 4 -AC was found to be 15 m 2 /g, while Co 3 O 4 -SG exhibited a slightly lower surface area of 11 m 2 /g. Co 3 O 4 -AC exhibited a higher specific capacitance (C s ) of 162 F/g at 0.25 A/g, indicating its superior energy storage capability. On the other hand, Co 3 O 4 -SG shows a C s of 98 F/g, indicating slightly lower performance compared to Co 3 O 4 -AC. Both nanomaterials exhibited better stability, with more than 85% capacity retention after 5000 charge–discharge cycles.