||In this study, the carbon electrode of supercapacitor was fabricated by using mesocarbon microbeads. For finding the optimal processing parameters of carbon electrode, the effects of specific surface area of activated carbon, the amount of carbon black and binder, and various electrolytes on the capacitative properties of supercapacitor are investigated. To fabricate the composite electrode of supercapacitor, NiO and WO3 thin films were deposited respectively on the carbon electrode by electron beam evaporation. The influences of various scan rates of cyclic voltammograms (CV) on the characteristic of capacitance are studied. The charge-discharge efficiency and life time of the composite electrode are also discussed.|
Experimental results reveal that the optimum carbon electrode can be obtained using mesocarbon microbeads with high specific surface area (2685 m2/g) and larger pore volume (0.6 cm3/g) and adding 10 wt.% carbon black and 2wt.% binder. The specific capacitances of carbon electrodes in 1 M KOH and 1 M Et4NBF4 are 230.8 F/g and 221.5 F/g, respectively. Besides, the XRD and SEM results showed that NiO and WO3 thin films on composite electrode are sheet-liked crystal structure and stone-liked amorphous structure, respectively. The composite electrode exhibits better capacitance properties than those of carbon electrode at high scan rate by CV analysis. It reveals the promotion of the capacitative property of supercapacitor at higher power density and the improving of the decay property in capacitance at high scan rate. Finally, in the test of charge-discharge efficiency and life time, the charge-discharge efficiency is near 100% after 5000 cycles and it still retains good adhesion between electrode material and substrate.