不同长度的棒状有序介孔炭的双电层电容性能

Electrochemical performance of rod-type ordered mesoporous carbons with different rod lengths for electric double-layer capacitors

  • 摘要: 将三嵌段共聚物P123既充当结构导向剂又作为碳源,通过硫酸处理,并采用直接炭化硅/P123复合材料的方法制备出棒状有序介孔炭,避免了传统硬模板法中需要除去昂贵的表面活性剂与反复浸渍的过程。通过改变合成参数,制备出不同长度的、从一微米到几十微米变化的棒状有序介孔炭材料。采用SEM,HR-TEM,XRD与N2吸脱附等对有序介孔炭材料的形态、结构以及孔特点进行表征,并将其作为双电层电容器的电极材料进行电化学测试,以期关联形貌、结构(尤其是棒长度)与其电化学性能的关系。结果表明在这些炭材料中,最长的介孔炭具有最高的比容量170 F/g。在2000 mA/g电流密度下,具有双孔径的介孔炭表现出最高的容量保持率(92%)。

     

    Abstract: Rod-type ordered mesoporous carbons were synthesized by the direct carbonization of sulfuric-acid-treated silica/triblock copolymer composites, followed by etching the silica with a HF solution. The morphologies, microstructures and pore structures of the mesoporous carbons were investigated by scanning electron microscopy, high resolution transmission electron microscopy, X-ray diffraction and nitrogen sorption. Their electrochemical performance as electrodes for supercapacitors was investigated by impedance spectroscopy and charge/discharge tests. It was found that the rod length of the mesoporous carbons can be changed from one to tens of micrometers by changing the synthesis parameters. The sample with the longest rod length has the highest specific capacitance. The sample with two pore sizes has the highest capacitance retention ratio of 92% at a high current density of 2 A/g.

     

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