High-surface-area and high-nitrogen-content carbon microspheres prepared by a pre-oxidation and mild KOH activation for superior supercapacitor
High-surface-area and high-nitrogen-content carbon microspheres prepared by a pre-oxidation and mild KOH activation for superior supercapacitor
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通过预氧化和温和的 KOH 活化制备高表面积和高氮含量的碳微球，用于优异的超级电容器
DOI：
10.1016/j.carbon.2017.03.075
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发表时间：
2017-07-01
期刊：
影响因子：
10.9
通讯作者：
Ling, Licheng
中科院分区：
文献类型：
--
作者：
Ma, Cheng;Chen, Xueyong;Ling, Licheng
KOH 活化是一种广为接受的开发多孔碳微孔的方法，但其剧烈的蚀刻反应可能不可避免地破坏结构完整性并削弱所得碳的杂原子表面化学性质。在此，我们报告了一种通过温和的 KOH 活化制备明确的微球形、高表面积和高氮掺杂碳的方法。我们的合成关键在于对由间苯二酚、甲醛和三聚氰胺制成的富氮聚合物微球进行预氧化，这可以将氮杂原子富集到所得的碳化骨架中，从而使碳易于被KOH活化，具有低表面蚀刻和高氮杂原子残留。所得碳具有2234-3121 m(2)/g的高比表面积、6.1-12.5 wt%的高氮含量和保存完好的球形形貌。当用作超级电容器的电极时，这些碳微球可以提供高达309 F/g的高比电容、优异的倍率性能以及在H2SO4电解液中循环5000次后高达96%的高循环性能。此外，发现氮官能团可以贡献相当大的赝电容，基本上是通过氮的法拉第反应。 (C) 2017 Elsevier Ltd. 保留所有权利。
KOH activation is a well-accepted approach to develop microporosity for porous carbons, but its severe etching reactions could inevitably destroy the structural integrity and diminish the heteroatomic surface chemistry of the resultant carbons. Herein, we report a method to prepare well-defined micro-spherical, high-surface-area and high-nitrogen-doping carbons via a mild KOH activation. The key to our synthesis relies in the pre-oxidation of the nitrogen-rich polymeric microspheres from resorcinol, formaldehyde and melamine, which could enrich nitrogen heteroatoms into the resultant carbonized framework, resulting in the carbon easily activated by KOH with low surface etching and high residual of nitrogen heteroatoms. The obtained carbons possess high specific surface area of 2234-3121 m(2)/g, high nitrogen content of 6.1-12.5 wt % and well-preserved spherical morphology. When used as the electrodes of supercapacitor, these carbon microspheres could deliver high specific capacitance up to 309 F/g, excellent rate performance and high cyclic performance of 96% after 5000 cycles in H2SO4 electrolyte. Furthermore, it is found that nitrogen functionalities could contribute considerable pseudo-capacitance, basically through Faradic reactions of the nitrogen. (C) 2017 Elsevier Ltd. All rights reserved.