||In this study, the carbon electrode of supercapacitor was fabricated by using mesocarbon microbeads. For finding the optimal processing parameters of carbon electrode, the capacitative properties of supercapacitor are investigated. To prepare the polymer gel electrolyte, NMP solution and two lithium salts, LiClO4 and LiBOB were adopted. The influences of different lithium salts of polymer gel electrolyte on the characteristics of supercapacitor are studied by using electrochemical impedance spectroscopy (EIS) and charge-discharge tests. Besides, the influences of different thicknesses of polymer gel electrolyte and different environment temperatures on the characteristics of supercapacitor are studied by using charge-discharge tests.|
Experimental results reveal that the optimum carbon electrode can be obtained using mesocarbon microbeads with high specific surface area (2620 m2/g) and adding 5 wt.% carbon black. The specific capacitance of carbon electrode in 1 M KOH is 260.48 F/g. Besides, the ohmic impedance, interface impedance with carbon electrode, rate of decline and specific capacity of polymer gel electrolyte prepared by LiClO4 are better than those prepared by LiBOB, so LiClO4 is selected the lithium salt ion of supercapacitor in this study. But the rate of decline of specific capacitance reach up to 39.26% after 30 times charge-discharge tests, so the ionic liquid is added to the polymer gel electrolyte, to reduce the rate of decline to 2.66%. According to literatures, appropriate thickness of polymer gel electrolyte is beneficial on the characteristics of capacitance. Experimental results reveal that the highest specific capacitance is 234.22 F/g when the thickness of polymer gel electrolyte is 177 μm in this study, then the energy density and the power density are 203.13 Wh/kg and 1.61 kW/kg.