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Increasing Accessible Subsurface to Improving Rate Capability and Cycling Stability of Sodium-Ion Batteries
Advanced Materials ( IF 27.4 ) Pub Date : 2021-08-01 , DOI: 10.1002/adma.202100808 Bo Yin 1, 2 , Shuquan Liang 1 , Dongdong Yu 2 , Boshi Cheng 2 , Ishioma L Egun 2 , Jiande Lin 1 , Xuefang Xie 1 , Hezhu Shao 3 , Haiyong He 2 , Anqiang Pan 1
Advanced Materials ( IF 27.4 ) Pub Date : 2021-08-01 , DOI: 10.1002/adma.202100808 Bo Yin 1, 2 , Shuquan Liang 1 , Dongdong Yu 2 , Boshi Cheng 2 , Ishioma L Egun 2 , Jiande Lin 1 , Xuefang Xie 1 , Hezhu Shao 3 , Haiyong He 2 , Anqiang Pan 1
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Numerous studies have reported that the enhancement of rate capability of carbonaceous anode by heteroatom doping is due to the increased diffusion-controlled capacity induced by expanding interlayer spacing. However, percentage of diffusion-controlled capacity is less than 30% as scan rate is larger than 1 mV s−1, suggesting there is inaccuracy in recognizing principle of improving rate capability of carbonaceous anode. In this paper, it is found that the heteroatom doping has little impact on interlayer spacing of carbon in bulk phase, meaning that diffusion-controlled capacity is hard to be enhanced by doping. After synergizing with tensile stress, however, the interlayer spacing in subsurface region is obviously expanded to 0.40 nm, which will increase the thickness of accessible subsurface region at high current density. So SRNDC-700 electrodes display a high specific capacity of 160.6 and 69.5 mAh g−1 at 20 and 50 A g−1, respectively. Additionally, the high reversibility of carbon structure insures ultralong cycling stability and hence attenuation of SRNDC-700 is only 0.0025% per cycle even at 10 A g−1 for 6000 cycles. This report sheds new insight into mechanism of improving electrochemical performance of carbonaceous anode by doping and provides a novel design concept for doping carbon.
中文翻译：
增加可接近的次表面以提高钠离子电池的倍率能力和循环稳定性
许多研究表明，通过杂原子掺杂提高碳质阳极倍率性能是由于扩大层间距引起的扩散控制容量增加。然而，当扫描速率大于 1 mV s -1 时，扩散控制容量的百分比小于 30%，表明对提高碳质阳极倍率性能的原理认识不准确。在本文中，发现杂原子掺杂对体相中碳的层间距几乎没有影响，这意味着扩散控制的容量很难通过掺杂来提高。然而，在与拉应力协同作用后，次表面区域的层间距明显扩大到 0.40 nm，这将增加高电流密度下可接近的次表面区域的厚度。因此 SRNDC-700 电极在 20 和 50 A g -1时显示出 160.6 和 69.5 mAh g -1的高比容量， 分别。此外，碳结构的高可逆性确保了超长循环稳定性，因此即使在 10 A g -1 下进行 6000 次循环，SRNDC-700 每个循环的衰减也仅为 0.0025% 。该报告对通过掺杂提高碳质负极电化学性能的机制提供了新的见解，并为碳掺杂提供了一种新的设计理念。
更新日期：2021-09-14
中文翻译：
增加可接近的次表面以提高钠离子电池的倍率能力和循环稳定性
许多研究表明，通过杂原子掺杂提高碳质阳极倍率性能是由于扩大层间距引起的扩散控制容量增加。然而，当扫描速率大于 1 mV s -1 时，扩散控制容量的百分比小于 30%，表明对提高碳质阳极倍率性能的原理认识不准确。在本文中，发现杂原子掺杂对体相中碳的层间距几乎没有影响，这意味着扩散控制的容量很难通过掺杂来提高。然而，在与拉应力协同作用后，次表面区域的层间距明显扩大到 0.40 nm，这将增加高电流密度下可接近的次表面区域的厚度。因此 SRNDC-700 电极在 20 和 50 A g -1时显示出 160.6 和 69.5 mAh g -1的高比容量， 分别。此外，碳结构的高可逆性确保了超长循环稳定性，因此即使在 10 A g -1 下进行 6000 次循环，SRNDC-700 每个循环的衰减也仅为 0.0025% 。该报告对通过掺杂提高碳质负极电化学性能的机制提供了新的见解，并为碳掺杂提供了一种新的设计理念。
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