炭化对沥青基活性炭纤维的结构和超级电容器性能影响

Effect of Carbonization on the Structure and Supercapacitive Performance of Pitch-Based Activated Carbon Fibers

以450℃低温炭化的各向异性中间相沥青基炭纤维为原料,先通过KOH化学活化方法制备出活性炭纤维(ACFs),再对ACFs进行炭化改性,以提高ACFs的导电率,系统地研究了炭化温度对ACFs微观形貌、结晶度、孔结构和超级电容器性能的影响。结果显示:经过1 200℃炭化处理的ACFs(ACFs^(-1)200)电极具有优异的电化学性能,在0.1 A·g^(-1)电流密度下比容量高达204 F·g^(-1),1 000次循环后电容保持率达到97.0%;且电流增至20 A·g^(-1)时依然具有高比容量(149 F·g^(-1)),表明ACFs^(-1)200电极相比于未炭化的ACFs,其导电率、大电流密度下的比容量、循环保持率均显著提高。

The porous activated carbon fibers（ACFs） were obtained by the anisotropic mesophase pitch carbon fibers carbonized at 450 ℃ through a simple KOH chemical activation method. In order to improve the degree of crystallinity of the ACFs, the as-prepared ACFs were modified by carbonization. The effects of carbonization temperatures on the morphology, crystallinity, pore structure and supercapacitive performances of ACFs were systematically investigated. The ACFs carbonized at 1 200 ℃（ACFs^（-1）200） electrodes exhibit excellent electrochemical performance with a specific capacity of 204 F·g^（-1） at 0.1 A·g^（-1）, which show a capacity retention of97.0% after 1 000 cycles. Even at 20 A·g^（-1）, the electrodes maintain a high specific capacity of 149 F·g^（-1）. The results show that the ACFs^（-1）200 electrodes deliver ultrahigh conductivity, high rate capacity and exceptional cycle stability compared with the non-carbonized ACFs electrodes.