Preparation and Electrochemical Properties of Hollow Nickel Oxide Fibers

In order to make better use of nano-nickel oxide particles, hollow nickel oxide fibers (HNOFs) were prepared by electroplating nickel particles on the surface of mesophase pitch based carbon fibers (MPCFs) and then burned off the carbon fibers under air atmosphere. Scanning electron microscopy showed that the HNOFs had hollow holes in center with diameter about 10 μm and the HNOFs fiber wall were made up of nickle oxide nanoparticles whose sizes ranged from 10 to 500 nm. The thickness of HNOF fiber wall can be controlled from tenths of micrometer to tens of micrometer. Thermogravimetric analysis and X-ray diffraction indicated that the nickel coated on MPCF surface was oxidized to nickel oxide when the heat treatment temperature was higher than 400 °C and the MPCF substrate decomposed when the temperature was higher than 600 °C. Moreover, the nickel oxide had a high crystallinity when the heat treatment temperature was higher than 700 °C. To be used as electrode for supercapacitor, the HNOFs showed well electrochemical properties. The specific capacitance of HNOFs with 0.8 μm fiber wall was 480 F/g with the current of 50 mA/g.