Performances of Electrical Double-layer Capacitors Composed of Pitch-based Activated Carbons

摘要

The ACS-series activated carbons with specific surface areas were produced from coal tar pitch by an alkali-activation program at China Steel Chemical Corporation. The surface area, porosity characteristics, and ash content of the activated carbons were characterized and compared with those of the coconut shell based activated carbons. The electrochemical performance of the electrode materials made of the activated carbons were investigated with a radical-type Electrical Double-Layer Capacitor (EDLC) assembly. The volumetric capacitance and specific energy of the electrodes were found to increase with the porosity of micropores, while the Dc resistance and leakage current had showed an opposite trend. The electrode consisting of energy-type activated carbon ACS15 or ACS20 could reach a maximum volumetric capacitance of 67 F/cc, and its specific energy was larger than 1.68 Wh/kg. The electrode made of activated carbon ACS25 had the advantage of power performance and exhibited a specific power higher than 4000 Wh/kg. Due to the low ash content, the EDLCs consisting of ACS-series activated carbons had shown an excellent electrochemical reliability under aging or cyclic charge-discharge conditions.