Studies On Supercapacitor Characteristics Of Nano-NiO/C

Supercapacitor is 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, electrolytes, preparation and assemble techniques and other related techniques with the aids of the measure methods such as cyclic voltammetric measurements(CV), constant charge/discharge measurements, Ac-impedance , X-rays diffraction(XRD), transmission electronic microscope measurements(TEM), scan electronic microscope(SEM), IR and so on. By experiments we got the conclusions as follows:1. The actived carbon electrode can provide better capacitance character in KOH solution, and its specific capacitance increased obviously with the increase of KOH solution concentration. When the concentration reached thirty percent, the specific capacitance of the electrode got to 200F/g which is maximal. The positive performance was one of the important factors of the effects to the supercapacitor performance. When the weight rate of the anode to the cathod was up to 2:1, the specific capacitance arrived at the maximum.2. In (NH4)2SO4 solution, the AC electrode could also perform better capacitance, which potential range get to 1.5V. That made the energy density and power density of the capacitor inhanced greatly.3. Nano-Ni(OH)2 was prepared by deposition methode, and the specific capacitance of nano-Ni(OH)2 is 90.7 F-g-1 in the KOH solution combined with active carbon. The cycl performance need be improved.4. Nano-NiO was obtained by heating Ni2CO3 which was synthesized byco-deposition method. The specific capacitance of the electrode arrived at 207.77 F-g-1 in 4mol-L-1 KOH solution, and the electrode's work potential was about 100~430mV(vs SCE). The capacitance could maintain at ninety percent after 5000 cycles.5. The specific capacitance and circle performance of Co-doped NiO obtained by addition Co(NO3)3 and Ni(NO3)2 to (NH4)2CO3 raised rapidly. When the content of Co was about twenty percent, the capacitance arrived at 224.38F-g"' which was maximal.6. The specific capacitance and circle performance of Ce-doped NiO obtained by addition Ce(NO3)3 and Ni(NO3)2 to (NH4)2CO3 raised rapidly. When the content of Ce was about four percent, the capacitance arrived at 272.10F-g"' which was maximal. The decrease of the capacitance was not distinct following the increase of the current.7. The Supercapacitor was fabricated by using Ce-doped NiO and active carbon, and the performance of the Supercapacitor was studied in 4mol-L-1 KOH solution. The results showed that the capacitance was increased largely compared by the active carbon Supercapacitor, and the increase of the energy density was more obvious.