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首页> 外文期刊>Journal of power sources >On the specific double-layer capacitance of activated carbons, in relation to their structural and chemical properties
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On the specific double-layer capacitance of activated carbons, in relation to their structural and chemical properties

机译：关于活性炭的特定双层电容，与其结构和化学性质有关

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摘要

Twelve well-characterized activated carbons with average micropore widths between 0.7 and 2nm, total surface areas of 378-1270m~2 g~(-1) and specific capacitances C up to 320 Fg~(-1) have been investigated, using H_2SO_4 2M as electrolyte. Some of the carbons have also been oxidized with (NH_4)_2S_2O_8, which leads to specific oxygen contents between 0.4 and 7.1 mu mol m~(-2) of carbon surface area. It appears that C_o, the limiting capacitance at a current density of 1 mA cm~(-2) of electrode surface, does not depend significantly on the oxygen content. An empirical equation is proposed to describe the decrease of C with increasing current density d (l-70mAcm~(-2) of electrode surface), as a function of the oxygen content. As suggested by different authors, C_o can be expressed as a sum of contributions from the external surface area S_e and the surface of the micropores S_(mi). A closer investigation shows that C_o/S_(mi) increases with the pore size and reaches values as high as 0.250-0.270Fm~(-2) for supermicropores. It is suggested that the volume W_o of the electrolyte found between the surface layers in pores wider than 0.7-0.8 nm contributes to C_o. However, this property is limited to microporosity, like the enthalpy of immersion of the carbons into benzene. The latter is also con-elated to C_o, which provides a useful means to identify potential supercapacitors.
机译：使用H_2SO_4 2M，研究了十二种表征良好的活性炭，其平均微孔宽度在0.7至2nm之间，总表面积为378-1270m〜2 g〜（-1），比电容C高达320 Fg〜（-1）。作为电解质。一些碳还被（NH_4）_2S_2O_8氧化，导致比表面积氧含量介于0.4和7.1μmolmol·（-2）之间。似乎C_o，即电极表面1 mA cm〜（-2）的电流密度下的极限电容，与氧含量无关。提出了一个经验公式来描述随着电流密度d（1-70mAcm〜（-2）电极表面）C的减少与氧含量的关系。正如不同作者所建议的那样，C_o可以表示为外表面面积S_e和微孔表面S_（mi）的贡献之和。进一步的研究表明，C_o / S_（mi）随着孔径的增加而增加，超微孔的值高达0.250-0.270Fm〜（-2）。建议在大于0.7-0.8nm的孔中在表面层之间发现的电解质的体积W_o有助于C_o。但是，这种性质仅限于微孔性，例如将碳浸入苯中的焓。后者也被称为C_o，C_o提供了一种有用的手段来识别潜在的超级电容器。

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