Preparation of Co-Ni Oxide/Vertically Aligned Carbon Nanotube and Their Electrochemical Performance in Supercapacitors

Abstract

A Co-Ni oxide/vertically aligned carbon nanotube (VACNT) composite was prepared by thermal decomposition of cobalt-nickel nitrate precursor on the surface of VACNT electrode. VACNTs were used as 3D nanoporous substrate and were grown by plasma-enhanced chemical vapor deposition from a mixture of H₂ and C₂H₂. The specific capacitance of Co-Ni oxide (5:5)/VACNT (with equal Co⁺²/Ni⁺² mole ratio) was measured to be 1050 Fg⁻¹, which is about 1.9- and 3-fold that of Ni oxide/VACNT (540 Fg⁻¹) and Co oxide/VACNT (341 Fg⁻¹), respectively. The results show Co-Ni oxide (5:5)/VACNT composite electrode has excellent specific capacitance because of porous network structure, good electrical conduction pathways, high access for the electrolyte solution, and consequently increased composite/solution interfacial contact area. The capacitance property of the Co-Ni oxide/VACNT composite electrode with different Co⁺²/Ni⁺² mole ratios was also investigated and the highest specific capacitance is achieved at equal Co⁺²/Ni⁺² mole ratio.

Keywords:

• Carbon nanotube
• Chemical vapor deposition
• Co-Ni oxide
• Energy storage
• Supercapacitor

Notes

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