Figure 5
The charge–discharge curves. The charge–discharge curves of the samples (a) pure MWCNT electrode at a current of 0.5 Ag−1, (b) pure Co3O4 electrode at a current of 0.5 Ag−1, (c) Co3O4/MWCNT electrode with different Co contents at a current density of 0.5 Ag−1, and (d) Co3O4-0.5/MWCNT electrode at different current density. Co3O4, cobalt oxide; MWCNT, multiwalled carbon nanotube.