Surface modification of activated carbon cloth and its application for the electrode of capacitor

为了获得高容量和高功率，作为双电层电容器电极的活性炭布（记为ACC）应具有较大的表面积。然而，表面上的表面功能物质可能导致容量的下降和内电阻率的增加。因此，ACC表面功能物质较少。它们通常是带氧的表面功能物质，具有酸性。用有机分析方法对其进行了表征，但其结构非常复杂。通过气相色谱-质谱和红外衍射反射光谱可以直接检测样品的表面物质。路易斯基材被吸附在表面。研究了表面物质与基材的相互作用。以炭化布为起始材料，在水蒸气中加热，研究炭化布的表面积变化及孔隙形成机理。在600℃以上，比表面积和孔径分布发生了显著变化。研究了表面物质的变化。通过对水蒸气的处理，发现存在两个过程。一种是表面物质不发生表面变化的分解过程，另一种是随表面积变化的活化过程。红外光谱结果表明，基材的吸附对表面物质有一定的影响，但伏安法结果表明，对容量影响不大。活化过程中处理的ACC容量逐渐增大。这表明表面积对ACC容量的影响很大。我们正在研究活化过程对容量的影响。

In order to obtain high capacity and high power, the activated carbon cloth (denoted as ACC) as the electrode of electric double layer capacitor should have large surface area. However, the surface functional species on the surface may cause the decrease in capasity and the increase in internal resistivity. Therefore, ACC should have less surface functional species. They are usually the surface functional species with oxygens and show acidic property. They were characterized by organic analysis method, but they were very complicated. We could directly check the surface species by GC-MASS and IR diffuce reflectance spectroscopy. Lewis base materials were adsorbed on the surface species. The interaction between the surface species and the adsorbed base materials was studied. Carbonized cloth, which was a starting material, was heated in water vapor to stydy the change in surface area and the formation mechanism of pore. The surface area and pore size distribution changed dramaticallyabove 600℃. The change of surface species was studied. We found that by the treatment in water vapor two processes existed.One was the decomposition process of surface species without no surface change, and the other, the activation process with the change in surface area. The surface species were effected by adsorption of base materials according to IR result, but the capacity was not affected largely according to voltammetry. The capacity of ACC treated during activation process gradually increased. This suggests that the surface area effected largely on the capacity of ACC. We are studing the effect of activation process on the capacity.