Synthesis And Capacitive Performance Of Ordered Porous Carbon Via A Template Method

In recent years, supercapacitor as a new type of energy storage device has received much more attention from governments and research workers. Porous carbon materials are usually used as the electrodes of electric double layer capacitors (EDLCs). Even the micropores are important for aqueous electrolyte system, however, when the micropore size is too small, the diffusion of the electrolyte ions will be restricted, which limits the capacitive performance of general porous carbon materials. Actually, the optimal conditions depend on the match between the pore structure of the porous carbon and the characteristic of the electrolyte. Based on the above depiction, in this paper, ordered microporous carbon materials with tailored pore structure were prepared by a template carbonization technique using Y zeolite, and their electrochemical performances were tested in different electrolytes in order to examine the appreciate relationship between the electrolyte ion size and the pore structure.First, ordered porous carbons were synthesized by using zeolite Y as the template and furfuryl alcohol (FA) as the carbon precursor. Effects of synthesis parameters on the structure of the product were studied. The surface area and the pore structure of the resultant carbons were characterized by physical adsorption of nitrogen and transmission electron microscopy (TEM). The highest surface area was 826 m2/g, and the pore size distribution of the product is narrow and almost all the pore sizes were in the range of 1.1-1.6nm.Then, the performance of the capacitors was tested in four different electrolytes, using constant current charge-discharge cycling, potential sweep cyclic voltammetry and altering current impedance. The highest specific capacitance achieved 129F/g at 1.0mA in NaOH. The performance of the capacitor in two kind of alkali electrolyte was better than that in others. The capacitor in KOH preserved a better shape of voltammery characteristics at the high scanning rate of 10mV/s. The impedance of the alkali electrolyte was smaller than that of others. In the research, the performance of capacitors in the alkali electrolytes with small size ions that can easily diffuse in the texture of the porous carbon was better than that in other electrolytes with large size ions, Results indicated that the best electrolyte was 1.5M KOH.