Research And Application Of Supercapacitors Of Aqueous Electrolytes

Supercapacitors are new energy storage components between batteries and electrostatic capacitors, which have higher power density and longer cycle life than batteries, and can be charged within a short time. They can be used as assistant power sources for electric components, power sources for small electrical equipments or pulse power sources. In addition, they can be used as driving system of electric vehicles with batteries.Supercapacitors can be classified electric double layer capacitors and pseudo-capacitors according to their working principles. Because electrode materials and electrolytes are important factors, we conducted a series of experiments to research on actived carbon, MnO₂, aqueous electrolytes, simulation of hybrid driving system with the aids of the measure methods such as cyclic voltammetric measurements(CV), impedance spectrum, constant charge/ discharge measurements, X-rays diffraction(XRD), leakage current, and so on.Firstly, actived carbon electrodes were actived by chemical methods and modified by Co²⁺. The result is that the performances of actived carbon actived by 65% HNO₃ or 98% H₂SO₄ are better than that of without disposition, and actived carbon electrode modified by Co²⁺ has electric double layer capacitors are enhanced, the capacitance of single electrode is 158.24F/g and is 26.8% higher than that of without modified when C:Co=13:1, and the capacitors of actived carbons modified by Co²⁺ have longer cycle life whose capacitance has been kept more than 91% after 1000 cycles. Secondly, we prepared MnO₂, by four methods and adulterated CoOOH into MO₂ power. The result is that the performance of the MnO₂ electrodes directly adulterated CoOOH is worse.Thirdly, we found (NH₄)₂SO₄ electrolytes is the best electrolyte for capacitors in the aqueous electrolytes according to a series of researches. The same time. Li₂SO₄ and Li₂CO₃ as additives were put into (NH₄)₂SO₄ electrolyte. The result is that Li₂SO₄ and Li₂CO₃ added into (NH₄)₂SO₄ electrolyte canimprove the capacitance, and the capacitance of adding U2CO3 is higher than that of adding U2SO4, especially for the hybrid electrochemical capacitors. When 0.368mol/L U2CO3 was added into (NH^SC^ electrolyte, the specific capacitance would be the highest and the capacitors had longer cycle life. Finally, when we used supercapacitors and batteries as the hybrid driving system, we found that the time of discharge for batteries was longer. This research will ground for the research on the power sources of hybrid electric vehicles.