Ultrahigh Nitrogen Doping of Carbon Nanosheets for High Capacity and Long Cycling Potassium Ion Storage
Ultrahigh Nitrogen Doping of Carbon Nanosheets for High Capacity and Long Cycling Potassium Ion Storage
复制标题
碳纳米片超高氮掺杂用于高容量和长循环钾离子存储
DOI：
10.1002/aenm.201902672
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发表时间：
2019-11-19
影响因子：
27.8
通讯作者：
Tang, Yongbing
中科院分区：
文献类型：
--
作者：
Chang, Xingqi;Zhou, Xiaolong;Tang, Yongbing
钾基储能器件（PESD）由于钾在自然界中丰富、钾（K）的低标准氧化还原电位（K/K+相对于标准氢电极为-2.93V）以及基于K离子的电解质的高离子电导率而成为大规模储能应用的有希望的候选者。然而，缺乏合适的阴极和阳极材料阻碍了PESD的实际应用。在这项工作中，成功地合成了掺杂有10%含量的氮（22.7at%）的碳纳米片作为用于K离子电池的阳极材料，其在500 mA g（-1）的电流密度下提供410 mAh g（-1）的高容量，这是用于PESD的碳基阳极中的最佳结果。此外，该电池表现出优异的循环性能，在5A g（-1）的高电流密度下3000次循环后容量保持率为70%。原位拉曼光谱、恒电流间歇滴定和密度泛函理论计算表明，氮化铝掺杂碳纳米片（UNCN）同时结合了扩散和赝电容机制，显著提高了其存储K离子的电化学性能.这些结果证明了UNCN作为PESD的高性能阳极的良好潜力。
Potassium-based energy storage devices (PESDs) are promising candidates for large-scale energy storage applications owing to potassiums abundant in nature, the low standard redox potential (-2.93 V for K/K+ vs the standard hydrogen electrode) of potassium (K), and high ionic conductivity of K-ion based electrolytes. However, lack of proper cathode and anode materials hinder practical applications of PESDs. In this work, carbon nanosheets doped with an ultrahigh content of nitrogen (22.7 at%) are successfully synthesized as an anode material for a K-ion battery, which delivers a high capacity of 410 mAh g(-1) at a current density of 500 mA g(-1), which is the best result among the carbon based anodes for PESDs. Moreover, the battery exhibits an excellent cycling performance with a capacity retention of 70% after 3000 cycles at a high current density of 5 A g(-1). In situ Raman, galvanostatic intermittent titration, and density functional theory calculations reveal that the ultrahigh N-doped carbon nanosheet (UNCN) simultaneously combines the diffusion and pseudocapacitive mechanisms together, which remarkably improves its electrochemical performances in K-ion storage. These results demonstrate the good potential of UNCNs as a high-performance anode for PESDs.