Cao Li, Huang Ting, Cui Mengya, Xu Jiejie, Xiao Rongshi
High-Power and Ultrafast Laser Manufacturing Lab Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing, 100124, China.
Small. 2021 Apr;17(14):e2005997. doi: 10.1002/smll.202005997. Epub 2021 Mar 11.
One-dimensional Si nanostructures with carbon coating (1D Si@C) show great potential in lithium ion batteries (LIBs) due to small volume expansion and efficient electron transport. However, 1D Si@C anode with large area capacity still suffers from limited cycling stability. Herein, a novel branched Si architecture is fabricated through laser processing and dealloying. The branched Si, composed of both primary and interspaced secondary dendrites with diameters under 100 nm, leads to improved area capacity and cycling stability. By coating a carbon layer, the branched Si@C anode shows gravimetric capacity of 3059 mAh g (1.14 mAh cm ). At a higher rate of 3 C, the capacity is 813 mAh g , which retained 759 mAh g after 1000 cycles at 1 C. The area capacity is further improved to 1.93 mAh cm and remained over 92% after 100 cycles with a mass loading of 0.78 mg cm . Furthermore, the full-cell configuration exhibits energy density of 405 Wh kg and capacity retention of 91% after 200 cycles. The present study demonstrates that laser-produced dendritic microstructure plays a critical role in the fabrication of the branched Si and the proposed method provides new insights into the fabrication of Si nanostructures with facility and efficiency.
具有碳涂层的一维硅纳米结构（1D Si@C）由于体积膨胀小和电子传输效率高，在锂离子电池（LIBs）中显示出巨大潜力。然而，具有大面积容量的1D Si@C阳极的循环稳定性仍然有限。在此，通过激光加工和脱合金化制备了一种新型分支硅结构。由直径小于100nm的初级和间隔次级枝晶组成的分支硅，提高了面积容量和循环稳定性。通过涂覆碳层，分支Si@C阳极的重量容量为3059 mAh g（1.14 mAh cm）。在3C的较高倍率下，容量为813 mAh g，在1C下循环1000次后保留759 mAh g。面积容量进一步提高到1.93 mAh cm，在质量负载为0.78 mg cm的情况下，100次循环后仍保持超过92%。此外，全电池配置的能量密度为405 Wh kg，200次循环后的容量保持率为91%。本研究表明，激光产生的树枝状微观结构在分支硅的制备中起着关键作用，所提出的方法为简便高效地制备硅纳米结构提供了新的见解。
