In situ fabrication of Ni(OH)2 nanofibers on polypyrrole-based carbon nanotubes for high-capacitance supercapacitors

Large-scale nickel hydroxide–carbon [Ni(OH)2/CNT] networks with three-dimensional electron-transport channels are synthesized via a facile and general surface-decoration approach, using polypyrrole-derived CNTs as the support. Flexible Ni(OH)2 nanofibers with a diameter of 5–10 nm and a length of 50–120 nm are intertwined and wrapped homogenously on carbon networks, leading to the formation of more complex networks. When used as supercapacitor electrodes, this designed architecture with large surface area, abundant pores and good electrical conductivity is very important in technology. It can promote the bulk accessibility of electrolyte OH− and diffusion rate within the redox phase. Consequently, an unusual specific capacitance of 1745 F g−1 can be obtained for Ni(OH)2/CNT composite at 30 mA cm−2. Even at a high rate (50 mA cm−2), the composite can also deliver a specific capacitance as high as 1118 F g−1, exhibiting the potential application for supercapacitors.