Effect of the pore length and orientation upon the electrochemical capacitive performance of ordered mesoporous carbons

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• 作者：Anran Huang^a ; ^b ; ^c ; Jingwang Yan^a ; ^b ; ^{yanjw@dicp.ac.cn} ; Hongzhang Zhang^a ; ^b ; Xianfeng Li^a ; ^b ; Huamin Zhang^a ; ^b ; ^{zhanghm@dicp.ac.cn}
• 关键词：Supercapacitor ; Hierarchical porous carbon ; Ordered mesoporous carbon ; Hard template
• 刊名：Journal of Energy Chemistry
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：26
• 期：1
• 页码：121-128
• 全文大小：1966 K
• 卷排序：26

文摘

By utilizing hard template method to adjust the mesopore length, and alkali activation to generate micropores, two hierarchical porous carbons (HPCs) were prepared. With controlling of their mesopore length and the activation conditions, the complex system composed by HPCs and electrolyte was simplified and the effect of mesopore length on the performance of HPCs as electrodes in supercapacitors was investigated. It is found that with the mesopore length getting smaller, the ordered area gets smaller and the aggregation occurs, which is caused by the high surface energy of small grains. HPC with long pores (HPCL) exhibits a donut-like morphology with well-defined ordered mesopores and a regular orientation while in HPC with short pores (HPCS), short mesopores are only orderly distributed in small regions. Longer ordered channels form unobstructed ways for ions transport in the particles while shorter channels, only orderly distributed in small areas, results in blocked paths, which may hinder the electrolyte ions transport. Due to the unobstructed structure, HPCL exhibits good rate capability with a capacitance retention rate over 86% as current density increasing from 50 mA/g to 1000 mA/g. The specific capacitance of HPCL derived from the cyclic voltammetry test at 10 mV/s is up to 201.72 F/g, while the specific capacitance of HPCS is only 193.65 F/g.