| Supercapacitors, a new energy storage components between batteries and electrostatic capacitors, when work with batteries, can meet the high power out-put need of electric vehicles when starting-up or acceleration for their power density could be tens times higher than that of batteries. They could also be used as electric components and power sources for small electrical equipment and direct current switches. Now supercapacitors have become a hotspot in research, and in many countries other than China, supercapacitors have been sucessfully used in electric vehicles. There isn't any report on applicable supercapacitors techniques or products in our country. For all purposes, it's very important to have study on supercapacitors for the promotion of electric vehicles in our nation. We conducted a series of experiments to research on electrode materials, selection and improvement of electrolytes and other related techniques such as cyclic voltammetric measurements (CV), constant charge/discharge measurements, X-rays diffraction(XRD), transmission electronic microscope measurements(TEM) and so on:1. The actived carbon electrode can provide better capacitance character in potassium hydroxide solution, and its specific capacitance increased obviously with the increase of KOH solution concentration. When the concentration reached thirty percent, specific capacitance of the electrode got to 200 F-g-1 which is maximal,and the capacitance could maintain at ninety percent after 5000 cycles. We also found that it was the smaller capacitance of the positive electrode that limits the performance of the AC electrode, and the specific capacitance increased when the ratio between the mass of positive actived material and that of negative actived material increased.2. In (NH4)2SO4 solution, the AC electrode could also perform better capacitance, which potential range got to 1.5V and was larger than in KOH solution. The difference of the positive electrode to the negative electrode was smaller. The specific capacitance of the elelctrode in (NH4)2SO4 solution was smaller than in KOH solution, and the corrosion degree to nickel was contrary.3. Acicular nano- nickel oxide was synthesized by chemical deposition ofnano-nickel hydroxide followed by heat-treatment in air at 300C. The specific capacitance of the nickel oxide was about 130F-g"' in the 9.0mol L"'KOH solution. The effects of scan speed, heating temperature and cycling on the specific capacitance were discussed.4. Nano-MnO2 whiskers were synthesized by low heating solid redox reaction using KMnO4 and MnSO4.The capacitor characteristics of nano-MnO2 whiskers were studied in 2.0 mol-L-1(NH4)2SO4 solution and 0.0-0.90V (vs SCE) potential range. The electrode can provide a specific capacitance of 304.5 Fg'1.5. Hydrous nano-MnO2 was synthesized by oxidation of aqueous MnSO4 in KMnO4 solution. The capacitor characteristics of hydrous nano-MnO2 were studied in 2.0 molL-1(NH4)2SO4 solution and 0.15-0.85V (vs SCE) potential range. The electrode can provide a specific capacitance of 158.9 Fg"1.6. Nano-MnO2 was synthesized by sol-gel method. The capacitance of the MnO2 electrode was 120.4 F-g-1 in 1 molL-1 (NH4)2SO4 solution by the method of constant charge/discharge when the current was 2mA.7. Nano-MnO2 was synthesized by glycin-nitrate burning method. The capacitance of the MnO2 electrode was 134.5 F-g-1 in 1 mol-L-1 (NH4)2SO4 solution by the method of constant charge/discharge when the current was 2mA.8. Using the method of adding addition (Na2SO4, K2SO4, MgSO4) to (NH4)2SO4 solution, the corrosion degree of ion NlV to nickel can be reduced. The effect of the content of addition and the concentration of the electrolyte to the electrochemical performance of MnO2 electrode and the corrosion degree of ion NH4+ to nickel was studied. The result showed that the capacitance of MnO2 electrode was retained and the corrosion degree of ion NH4+ to nickel was reduced, when the molar content of MgSCO4 was 50% and the molar c...
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