Preparation And Performance Study On Carbon Composite For Super-Capacitor Electrode Materials

Super-capacitor is a new kind of energy storage device and a clean of green energy, with quick charge and discharge, high efficiency, as well as good stability, a large market potential. A great deal of experimental research work on the super-capacitor electrode materials was performed to mainly discuss the electrochemical performance of porous carbon materials as super-capacitor electrode materials.The main purpose of this paper is to make porous carbon materials of high performance to make a super-capacitor have a stable performance. In the experiment, I have prepared the carbon aerogels, coconut shell activated carbon and its modification, phenolic resin based activated carbon and Graphene, which were used as super-capacitor electrode materials. The structure and surface functional groups of the carbon materials were characterized by Fourier transform infrared spectroscopy(FT-IR), X-ray diffraction analysis(XRD), Raman spectroscopy(RS), BET adsorption test, scanning electron microscopy(SEM). Super-capacitor through constant current charge and discharge, circulation volt-ampere, circulation performance tests to measure the electrochemical performance. The effects of structure properties to super-capacitor electrochemical performance were analysed by observing structure and surface properties of all kinds of carbon materials, combining with electrochemical test resuls.The results show that the carbon aerogels prepared through sol-gel process appears as a small ball and uniformly distributed, whose surface area was 451.65m2/g. The specific capacitance was 118.06F/g at 10mA, when 50mA is 108.64F/g, which showed that it was suitable for macrocurrent charge-discharge, and the cycle property was stable. When the coconut shell activated carbon was modified by concentrated HNO3, its surface area and surface functional groups were all increased. The specific capacitance of it raised from 79.1F/g to 112.13 F/g, increased 41.8%, with a stable property and a long cycling life. The phenolic resin-based activated carbon activated by KOH had a biggest specific capacitance at 10mA, which reached 140.26F/g. When Graphene wae used in the super-capacitor, it had a small resistance, with 152.74F/g specific capacitance at 50mA, which was suitable for high power charging and discharging.To improve the performance of the super-capacitor, and reduced the cost, compounded carbon materials to make super-capacitor. The results showed that Graphene/ phenolic resin-based activated carbon composites had a higher specific capacitance than pure Graphene, the composites prepared at a ratio of 2:1 increased by 24.9%,and a ratio of 1:2 increased by 14%. Graphene/ phenolic resin-based activated carbon composites used in the super-capacitor can increase specific capacitance, reduced the cost, which was a feasible compounded way.