Achieving Slope-Reigned Na-Ion Storage in Carbon Nanofibers by Constructing Defect-Rich Texture by a Cu-Activation Strategy
Achieving Slope-Reigned Na-Ion Storage in Carbon Nanofibers by Constructing Defect-Rich Texture by a Cu-Activation Strategy
复制标题
通过铜激活策略构建缺陷丰富的织构，实现碳纳米纤维中斜率控制的钠离子存储。
DOI：
10.1021/acsami.9b17610
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发表时间：
2020
影响因子：
9.5
通讯作者：
Zhou Jisheng
中科院分区：
文献类型：
--
作者：
Guo Xu;Xue Yunyan;Zhou Hongfu;Weng Yunxuan;Zhou Jisheng
硬碳作为钠离子电池（SIB）阳极材料已显示出广阔的应用潜力，但调整硬碳的结构以操纵其电化学行为仍然是一个巨大的挑战。在这项工作中，开发了一种铜激活策略来控制硬碳纳米纤维的缺陷，以实现斜率控制的钠离子存储行为。该方法可以通过使用少量的Cu(NO3)2作为活化剂来有效地产生富含缺陷的碳织构，但不能引起表面积的增加。添加Cu活化剂后，通过静电纺丝和随后的退火合成了缺陷增加的碳纳米纤维。当碳纳米纤维用作SIB阳极时，其可逆容量随着缺陷的增加而增加。同时，斜坡容量逐渐增加，低压平台容量逐渐减少。特别是，缺陷较多的Cu活化纳米纤维的可逆容量可提高至315 mAh g-1，几乎没有平台容量，而失活纳米纤维的可逆容量为203 mAh g-1，平台容量为26%。值得注意的是，活化纳米纤维的初始库仑效率（70%）仅略低于失活纳米纤维的初始库仑效率（72%）。铜激活纳米纤维还表现出卓越的倍率性能和长循环寿命。因此，这项工作为设计具有优异钠离子存储性能的富缺陷硬碳提供了一条新途径。
Hard carbons have shown promising application potential as anode materials for sodium-ion batteries (SIBs), but adjusting the texture of hard carbons to manipulate their electrochemical behaviors remains a great challenge. In this work, a Cu-activation strategy is developed to control the defects of hard carbon nanofibers to achieve slope-reigned Na-ion storage behaviors. This method can effectively create defect-rich carbon texture by employing a small amount of Cu(NO3)2as an activator but cannot induce an increase in the surface area. With the addition of the Cu activator, carbon nanofibers with increasing defects are synthesized by electrospinning and subsequent annealing. When carbon nanofibers are used as anodes for SIBs, their reversible capacity is increased with the increase of defects. Simultaneously, slope capacity gradually increases, while low-voltage plateau capacity reduces. Especially, the reversible capacity of Cu-activated nanofibers with more defects can be increased to 315 mA h g–1with almost no plateau capacity compared with 203 mA h g–1of inactivated nanofibers with a plateau capacity of 26%. Noticeably, the initial Coulombic efficiency (70%) of the activated nanofibers is just slightly lower than that (72%) of inactivated ones. The Cu-activated nanofibers also demonstrate superb rate performance and long cycle lifetime. Therefore, this work shows a new pathway for the design of defect-rich hard carbons with superior Na-ion storage performance.