Study On Electrode Materials For Electrochemical Capacitor

As a new kind of energy storage component, electrochemical capacitor (EC) is characterized with high energy density, high power density, long life time and wide temperature range for using. ECs have already found applications in fields such as high power start-up system, movable energy system and back-up electrical power. For the wide application field and huge commercial value, more and more attention is being paid on the studies on ECs. Studies on ECs are mainly focused on the preparation of high performance electrode materials. In this dissertation, the work is mainly focused on the preparation of high specific surface area mesoporous AC, research on nanosized NiO EC and NiO hybrid capacitor, studies on modification of CNTs and preparation of CNTs composite, research on spiral wound EC based on activated carbon fibre cloth (ACFC). The main results are as following.1. High specific surface area mesoporous AC was prepared by chemical activation of petroleum coke. The prepared AC has a specific surface area of 1733 m2/g, a mean pore diameter of 2.37nm and a mesopore volume fraction of 60.6%. In an electrolyte of 30wt% KOH , the specific capacitance, energy density and usage efficiency of specific surface area of the AC is 180F/g, 6.38Wh/kg and 51.93%, respectively. When the current density is increased from 150mA/g to 1.2A/g, the decrease of the specific capacitance is only 9.5%.2. Nanosized NiO synthesized by precipitate-transformation method was used as electrode materials for pseudocapacitor. The mean diameter of the prepared NiO is about 10nm. At a current density of 60mA/g, the NiO reaches a specific capacitance of 243F/g. The results show that precipitate-transformation method is a simple, cheap and effective method for preparation of nanosized NiO for EC. NiO-AC hybrid capacitor was also studied. The hybrid capacitor has a working voltage of 1.5V and a much better power performance. The energy density of the hybrid capacitor is 17.2 times higher than that of the NiO EC.3. In order to increase the specific capacitance of the CNTs, Activation of CNTs was carried out by using KOH. By activation treatment, the specific surface area of...