Nickel oxide/carbon nanotubes (NiO/CNTs) composite materials for supercapacitor are prepared by chemically depositing of nickel hydroxide onto CNTs pretreated by ultrasonication and followed by thermal annealing at 200-300°C. A series of NiO/CNTs composites with different weight ratios of CNTs and different annealing temperature are synthesized via the same route. The scanning electron microscope (SEM) images show that the nucleation of the nickel hydroxide formed on the outer walls of CNTs due to ultrasonic cavitations, and then nickel oxide coated uniformly on the outer surface of the individual CNTs after thermal annealing. The NiO/CNTs electrode presents a maximum specific capacitance of 254 F/g as well as a good cycle life in 2 M KOH electrolyte. The good electrochemical characteristics of NiO/CNTs composite can be attributed to the three-dimensionally interconnected nanotubular structure with a thin film of electroactive materials.
Nickel Hydroxide as an Active Material for the Positive Electrode in Rechargeable Alkaline Batteries