The Preparation Of The Nickel Anode Oxide Film Electrode And Its Electrochemical Performance

The super capacitor is a new type of electrochemical energy storage device between rechargeable batteries and dielectric capacitors, which may be ten times higher than batteries in power density and ten times higher than electrostatic capacitor in energy density. It has been a hot spot in recent research for its excellent prospects for applications in the fields of electric vehicle's accelerating and braking system, moving communication, information technology, aviation, national defensive technology, etc.The features, current investigation status and materials in respect to super capacitors are presented in the thesis. And the preparation technical conditions and electrochemical performance of nickel oxide and nickel super capacitors' are researched. The effect of the experiment parameters on specific capacity and specific surface was basically discussed.The experiment selects Titanium alloy as the base, and makes nickel electroplated on Titanium alloy so that the membrane is formed on the surface, and oxidizes the anodic membrane to nickel oxide, and last the electrode is prepared. The composition and performance is tested by the X-ray diffraction (XRD), charge/discharge test, chronoamperometry(CA), cyclic voltammeter(CV), Tafel technology etc. The results are concluded as follows.1. The nickel oxide can not be found from XRD patterns, only nickel and titanium are found. Because the film was so thin that the X-ray penetrated the film into the titanium base. But the existence of nickel oxide still can be confirmed by comparing the effective surface area. The effective surface area of nickel oxide is much larger than that of nickel. The effective surface area of the sample was found getting much larger than before, so it was concluded that the nickel was oxidated to nickel oxide at the anode electrode.Among those electrode materials prepared from the electroplating-anodic oxidation method, the best conditions as follows: the KOH concentration is at 4 mol/L, oxidation temperature is at 60°C, oxidation voltage is at 1.1V, oxidation time is for 2h. Oxidation temperature affects the electrochemical performance most, and the next is KOH concentration.3. The charge/discharge test of the nickel anodic oxidation membranes shows that the electrode discharge voltage attenuates smoothly. The electrode has the largest sub capacitance and specific discharge capacity at 60°C. The CA test expresses the specific surface area of the electrode reaches the maximum at the oxidation temperature of 60°C. The CV teat displays that there are oxidation and reduction peaks at low oxidation temperature. With oxidation temperature increasing, the height of the peaks descends. When temperature comes to 60°C, the peaks disappear. The CV curve is similar to rectangle, and so the electrode has fine performance. Tafel test indicates that the exchange electric current density and reaction rate gets better with oxidation temperature increasing.4. The experiment shows that the nickel oxide electrode obtained at 60°C has the potential for super capacitor material.