A simple wet-chemical synthesis, reaction mechanism, and charge storage application of cobalt oxide electrodes of different morphologies

•Facile and low-temperature wet chemical synthesis strategy for obtaining various Co3O4 nanostructures is reported.•Structural elucidation confirms the formation of face-centered cubic Co3O4.•Nano-platelet, nano-needle and nano-grass-type morphologies are corroborated.•Nano-grass-type Co3O4 electrode demonstrates higher specific capacity (66.40 mAh g−1 at 1 mA cm−2 current density) than that of nano-platelets (23.22 mAh g−1) and nano-needles (61.22 mAh g−1)-type Co3O4 electrodes.

In the present work, cobalt oxide (Co3O4) electrodes of different morphologies are synthesized onto a stainless-steel (SS) substrate by a simple and cost-effective wet chemical deposition method in presence of different cobalt precursors and then used for energy storage application. Chemical reactions, responsible for different morphologies, are proposed and structural elucidation and morphological evolution studies of Co3O4 electrodes are attempted. Nano-platelets, nano-needles, and nano-grass-type of surface morphologies, corroborated from the scanning electron microscopy and the transmission electron microscopy digital photoimages, for cobalt acetate, cobalt chloride, and cobalt nitrate precursors of Co3O4 electrodes are obtained, respectively. Electrochemical analysis revealed that nano-grass-type Co3O4 electrode exhibits higher specific capacity (SC) (66.40 mAh g−1 at 1 mA cm−2 current density), excellent cycle life (∼90% after 1000 cycle) and high rate capability (77%) than that of nano-platelets (23.22 mAh g−1) and nano-needles (61.22 mAh g−1)-type Co3O4 electrodes.

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