Preparation And Electrochemical Capacitive Performance Of Porous Carbon Materials

The main work in this paper is to figure out excellent methods of preparing activated porous carbon materials. We investigate some methods to prepare materials with higher surface area and pore structures, some of them were picked up and their electrochemical properties are proved by the relatively high capacity and rate performance.1. A series of porous carbon were prepared by using sucrose as the precursor and poly ethylene glycol (PEG) as the pore-forming and structure-directing agent through hydrothermal carbonization. The effects of the amount and molecular weight of polyethylene glycol and surfactants on spherical morphologies were studied. The results show that the optimal formula for adding PEG2000with1.5gram can synthesis a spherical carbon with better capacitive performance, the specific surface area is2464m2·g-1after treated by KOH.2. A series of carbon materials were synthesized by using carbohydrate as precursors and ferric nitrate/nickel nitrate as pore-forming agents by a hydrothermal method. The effects of carbon sources, the amount of inorganic salts on the morphologies of the products were studied. The mesoporous structure increased significantly when the Iron and nickel nitrate was added, thus the hierarchical porous carbon can be obtained easily. And Galvanostatic charge/discharge and cyclic voltammetry measurements indicate the carbon shows high capacitance and excellent rate capability in aqueous electrolytes. The capacitance in6mol·L-1KOH can be305F·g-1and212F·g-1at0.05A·g-1and50A·g-1, respectively. While in lmol·L-1Et4NBF4/PC, the capacitance can be as high as132F·g-1at0.05A·g-1.3. Hierarchical porous carbon is prepared from sucrose by nano-CaCO3template method and followed NaOH activation for supercapacitors. The specific surface area and pore volume reach up to2025m·g-1and2.602cm3·g-1, respectively. In6mol·L-1KOH aqueous electrolytes, it can afford a capacitance of245F·g-1at0.05A·g-1, which remains188F·g-1as the current density increases up to50A·g-1, while the value reaches144F·g-1at0.05A·g-1and maintains103F·g-1at10A·g-1in lmol·L-1Et4NBF4/PC non-aqueous electrolytes.4. The method of direct carbonation of cobalt acetate was used to prepare graphitic porous carbon materials under a succession of temperatures (700,800and900℃) in N2. The organic salt precursor decomposed firstly and then the cobalt in the intermediate product performed as catalyst to help to induce the graphitization, after the removal of them can also obtain numerous accessible porosity structures as well. However, the higher temperatures can lead to higer degree of the graphitization, and the product prepared at800℃ possesses better pore structures and higher specific surface area.