N/S codoped carbon microboxes with expanded interlayer distance toward excellent potassium storage
N/S codoped carbon microboxes with expanded interlayer distance toward excellent potassium storage
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DOI：
10.1016/j.cej.2018.10.135
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发表时间：
2019-02-15
影响因子：
15.1
通讯作者：
Liu, Meilin
中科院分区：
文献类型：
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作者：
Li, Youpeng;Zhong, Wentao;Liu, Meilin
用于钾离子电池（PIB）的碳质材料因具有成本效益的特征而相当有吸引力。然而，基于PIB的碳质阳极材料的循环稳定性和倍率性能受到限制，因为难以容纳大的K离子（1.38埃）。因此，通过碳化-蚀刻工艺制备具有增加的层间距的氮（N）和硫（S）共掺杂的碳微盒（NSC）。与传统石墨中K离子难以插入受限的层间距不同，NSC显示出0.412 nm的极大层间距，使得K离子在NSC中的插入/提取过程中更加灵活。此外，非原位TEM研究表明，在钾化/脱钾过程中，NSC的层状结构保持良好。因此，NSC提供了超长的循环寿命（1000次循环后在500 mA g（-1）下为180.5 mAh g（-1））和非凡的倍率能力（在2 A g（-1）下为155.6 mAh g（-1）），这使得NSC成为PIB的有前途的阳极材料。
Carbonaceous materials for potassium-ion batteries (PIBs) are quite attractive for the cost-effective feature. However, the cycle stability and rate performance of carbonaceous anode materials based on PIBs are limited, for the difficulty of accommodating large K ions (1.38 angstrom). Thus, the nitrogen (N) and sulfur (S) codoped carbon microboxes (NSC) with increased interlayer spacing is prepared via a carbonization-etching process. Unlike the traditional graphite, in which the K ions are difficult to insert into the restricted interlayer spacing, the NSC displays extremely large interlayer spacing of 0.412 nm, making the K ions more flexible during the insertion/extraction process in NSC. Moreover, ex-situ TEM study reveals that the layer structure of NSC is well-remained during the potassiation/depotassiation process. As a result, the NSC delivers super-long cycle life (180.5 mAh g(-1) at 500 mA g(-1) after 1000 cycles) and extraordinary rate ability (155.6 mAh g(-1) at 2 A g(-1)), which makes the NSC a promising anode material for PIBs.