Double-carbon protected silicon anode for high performance lithium-ion batteries
Double-carbon protected silicon anode for high performance lithium-ion batteries
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DOI：
10.1016/j.jallcom.2019.151848
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发表时间：
2020-01
影响因子：
6.2
通讯作者：
Lin-hui Zhu;Yan-li Chen;Changqing Wu;Ruixia Chu;Jie Zhang;Heng Jiang;Yibo Zeng;Ying Zhang
中科院分区：
文献类型：
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作者：
Lin-hui Zhu;Yan-li Chen;Changqing Wu;Ruixia Chu;Jie Zhang;Heng Jiang;Yibo Zeng;Ying Zhang
硅/碳复合材料无疑是最有前途的锂离子电池负极材料之一。然而，尽管引入了碳相，但它们仍然遭受差的循环性能，通常期望碳相抑制Si相的体积膨胀，同时丰富电极导电性，提高循环稳定性。本文设计并采用液相包覆原位聚合法成功制备了双碳保护硅阳极。在这种结构中，原生无缝碳层使硅纳米颗粒与导电碳保持紧密接触，使得嵌入的Li+能够与Si充分反应，提高了活性材料的利用率。二次碳骨架可以帮助保持结构的机械完整性，同时丰富电荷转移通道。该结构优点增强了循环期间的机械完整性和电化学动力学，这导致上级电化学Li+存储性能。所得到的双碳保护硅阳极表现出高比容量、长期稳定性（在0.5 mA g − 1下为1919 mAh g− 1，400次循环后保持率为90%（与第二次循环的容量相比））和出色的倍率性能（在2 A g−1下为1170 mAh g−1）。
Undoubtedly, silicon/carbon composites are one of the most promising anode classes for lithium-ion battery. However, they still suffer from poor cycle performance despite the introduction of carbon phase, which is usually expected to inhibit the volume expansion of Si phase and meanwhile enrich the electrode conductivity, improving the cycle stability. Here, a double-carbon protected silicon anode was designed and successfully synthesized through the liquid coating and in-situ polymerization method. In this structure, the primary seamless carbon layer make Si NPs maintain a close contact to conducting carbon, so that inserted Li+could fully react with Si, improving the utilization of active materials. The secondary carbon skeleton could help to maintain the mechanical integrity of the structure and meanwhile enrich the charge transfer channels. The structural advantages enhance the mechanical integrity and electrochemical kinetics during cycling, that lead to superior electrochemical Li+storage performance. The resulting double-carbon protected silicon anode demonstrates a high specific capacity, long-term stability (1919 mAh g−1at 0.5 mA g−1, 90% retention after 400 cycles (vs. the capacity of second cycle)) and outstanding rate capability (1170 mAh g−1at 2 A g−1).