Research On The Metal Oxide Electrode Materials Of Electrochemical Capacitors

Super capacitors as a new kind of maintaining power device are attracting more attention for their advantages such as high power density, long cycle life, green environment protection, etc. Super capacitors are widely used in industrial large UPS power supply, electric vehicle, aerospace, etc. In this paper, the author investigates the effects of the preparation methods and doping on the performance of super capacitors used V₂O₅, TiO₂ and NiO as the electrode materials.This paper has mainly been performed though the following aspects:1. Liquid phase method and sol-gel method were used to prepare the submicron V₂O₅ powder material, and the electrochemical characteristics of prepared V₂O₅ were studied. The V₂O₅ prepared by sol-gel method showed good capacitance characteristic in LiCIO4 or LiPF6 or Et4NBF4 electrolyte. The results of CV and constant current discharge show that the V₂O₅ capacitors have best characteristic in 1M LiClO4 electrolyte and the specific energy reaches 20.2Wh/kg.2. The capability and power characteristics of V₂O₅ are improved by doping Ni and Sn, the specific surface area of V₂O₅ doped Sn or Ni complex material is 92m2/g and 121m2/g, respectively. The specific power is respective 15.6Wh/kg and 54.5Wh/kg. The specific surface area after carbon doped achieves 499m2/g and the conductivity is improved.3. The anatase TiO₂ complex electrode was prepared by doping the Ni or C element into TiO₂. The author used XRD, SEM, CV, EIS and constant current discharging method to check the influence of doping Ni or C elements on the crystal structure and electrochemical characteristic of TiO₂.4. Ball milling method was used to prepare the Ni(OH)₂, and the specific surface area of the material is 100.37m2/g. The results of CV, EIS and constant current discharging test show that the Ni(OH)₂ has pseudo capacitance characteristics. After 250℃treatment, the electrochemical test shows that the specific power and the specific surface area of NiO is 952.2W/kg and 175m2/g, respectively. The author first made the material into slurry, and then coated it onto the Ni foam, and finally made SC steel shell electrochemical capacitors. And the series-parallel characteristics were tested and the effects of series-parallel on power characteristics were discussed.5. Research on NiO elelctrode materials prepared by the microwave method. The effects of the microwave power and reaction time on the performance of prepared NiO materials were studied. The best preparation condition is 135s with 640W. The preparation method is that the Ni₂SO₄ and some certain compounds containing doping elements were mixed, NiO was prepared with microwave method. The specific surface area of NiO with the proportion Al/Ni= 0.3 is 202m²/g, with Co/Ni=0.4 is 146m²/g, The best proportions are found to be Al/Ni=0.3 and Co/Ni=0.4.