Nickel hydroxide was deposited on the surface of modified carbon nanotubes (CNTs) by improved precipitation process, and NiO/CNTs composites were obtained by calcination at 300 ℃. Physical properties of the mixture with different contents of carbon nanotubes were examined by X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and Brunauer-Emmett- Teller (BET) surface area measurement. The electrochemical performances were studied by cyclic voltammograms, galvanostatic charge/discharge. The results indicated that the introduction of suitable amount of CNTs would result in good capacitive behavior and high-rate capacity, which were brought by good dispersion of NiO. The specific capacitance of composite electrode is up to 309 F•g^－1 when the mass fraction of CNTs in the composite is 20%. When deducted the contributions of CNTs (35 F•g^－1), the specific capacitance of nickel oxide reaches 420 F•g^－1 in NiO/40% CNTs composite electrode. All of these had an obvious improvement compared with pure phase nickel oxide (175 F•g^－1).

Key words: supercapacitor, nickel oxide, carbon nanotube, composite electrode