Construction of cobalt substituted α-Ni(OH)2 hierarchical nanostructure from nanofibers on nickel foam and its electrochemical performance

Co-substituted α-Ni(OH)2 nanofibers-composed hierarchical nanostructure was built in the presence of urea through a hydrothermal route. The morphology of nanofibers originated from the curling up of nickel hydroxide nanosheets under hydrothermal condition. The hierarchical nanostructure resulted from the upward growth of nanofibers with their one end on the surface of nickel foam. This delicate structure of material provided a facile pathway for the fast transfer of electrolyte during the electrochemical reactions. On the other hand, the intimate connection between material and nickel foam reduced the contact resistance of electrode. As a result of the two advantages, the Co-substituted α-Ni(OH)2 had excellent electrochemical performance. The 11.1% Co-substituted α-Ni(OH)2 exhibited a high specific capacitance of 2687 F/g at current density of 1.1 A/g and remained a high specific capacitance of 1335 F/g at high current density of 35.3 A/g. These results suggest that this Co-substituted α-Ni(OH)2 nanofibers are a promising candidate for the electrode materials of supercapacitors.