Hydrothermal process fabrication of NiO–NiCoO2–Co3O4 composites used as supercapacitor materials

• Published in: Journal of materials science. Materials in electronics 2017-10, Vol.28 (20), p.14928-14934
• Main Authors: Wang, X. W., Wang, X. E., Liu, Y. P., Kong, Y. Y., Sun, L. Y., Hu, Y. C., Zhu, Q. Q.
• Format: Article
• Language: English
• Subjects: Capacitance; Characterization and Evaluation of Materials; Chemistry and Materials Science; Cobalt oxides; Electrochemical impedance spectroscopy; Electron microscopes; Energy storage; Field emission microscopy; Materials Science; Nickel oxides; Optical and Electronic Materials; Storage systems; Supercapacitors
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-017-7364-x

A composite consisting of Co 3 O 4 , NiCoO 2 and NiO is prepared by a simple and easy hydrothermal method followed by calcining at 300 °C. The composition, morphology and microstructure of NiO–NiCoO 2 –Co 3 O 4 composites are examined by X-ray diffraction, field emission scanning electron microscope and transmission electron microscopic. The electrochemical performances of NiO–NiCoO 2 –Co 3 O 4 composites are characterized by cyclic voltammetry, galvanostatic charge–discharge and electrochemical impedance spectroscopy in 3 M KOH electrolyte. The results of electrochemical measurements show that the NiO–NiCoO 2 –Co 3 O 4 composites exhibit a high specific capacitance of 990 and 580 F/g at the current densities of 1.0 and 10 A/g, respectively. About 50% of the maximum specific capacitance can still be retained after 1000 continuous CD cycles at 10 A/g. It reveals a great potential of NiO–NiCoO 2 –Co 3 O 4 composites used in high-performance energy-storage systems.