Study On Electhode Materials Of High Surface Area Activated Carbon With Different Pore Structures For Supercapacitor

With the growing development of renewable energy sources as well as hybrid electric vehicles (HEV), the light-weight and compact electric power sources is supplying the increasing demand. Among them, supercapacitors have received much attention recently,because of their power delivery performance that perfectly fills the gap between dielectric capacitors and traditional batteries. Nowadays, supercapacitors have been widely used in many fields, including energy storage and power output technologies for portable electronics, electric vehicles, and renewable energy systems operated on intermittent sources. A variety of materials such as activated carbon, transition metal oxides and conducting polymers, etc, are currently investigated for use as electrode materials for supercapacitor. Activated carbons are the most widely used electrode material for supercapacitors because of their relatively low cost,high surface area and good electrical conductivity.In this study, we report a facile and efficient route to prepare a series of activated carbons, which have different micropore-mesopore architecture. Activated carbons are characterized by thermal gravimetric analysis, X-ray diffraction, nitrogen adsorption/desorption isotherms and transmission electron microscope. And the results showed that the specific surface area and the pore volume of both mesopores and micropores of the resultant carbons were enhanced remarkably. And the KOH/ZnCl₂/PF weight ratio and activation temperature have a marked effect on the porosity, the specific surface area and the pore volume of the carbons.The electrochemical performance of the activated carbons are investigated in an organic electrolyte of 1 M Et₃MeNBF₄/PC. The results show that the more and turnable micropore greatly improved the specific energy of the supercapacitor, moreover, the randomly connected mesoporous provided fast diffusion channel for electolyte and opened up closed micropore which increased the utilization of micropore. The best compromise of meso/micro ratio have been found, which significantly enhanced the supercapacitor performance. Among them, the sample of PC-6 prepared with a KOH/ZnCl₂/PF ratio of 1:2:2 shows the most stable electrochemical performance at the different charge–discharge rates. The sample PC-6 presents a high specific capacitance of 142 F g^-1 in organic electrolyte and a maximum energy density of 36Wh kg^-1. The good electrochemical behavior of PC-6 was attributed to the good development pore structure, high surface area, large pore volume, as well as well balanced microporosity and mesoporosity.