Three-Dimensional Carbon Nanotubes Buffering Interfacial Stress of the Silicon/Carbon Anodes for Long-Cycle Lithium Storage
Hao Li, Binghua Yao, Ming Li, Xingchi Zou, Ruixian Duan, Haoqi Li, Qinting Jiang, Guiqiang Cao, Jun Li, Huanyu Yan, Na Xu, Bo Sun, Jingjing Wang, Xifei Li
Abstract
Silicon/graphite composites show a high specific capacity and improved cycling stability. However, the intrinsic difference between silicon and graphite, such as unequal volume expansion and lithium-ion diffusion kinetics, causes persistent stress at the silicon/graphite interface and the expansion of the electrical isolation region. Herein, carbon nanotubes (CNTs) were successfully introduced into silicon/carbon composites via ball milling and spray drying, which effectively relieved the stress concentration at the direct contact interface and formed a three-dimensional conductive structure. In addition, CNTs and amorphous carbon acting as “lubricants” further improved the inherent differences between silicon and graphite. As a result, the Si/CNTs/G@C-1 anode increased the cycling performance and rate capability, with a reversible capacity of up to 465 mAh g –1 after 500 cycles at 1 A g –1 and superior rate performance of 523 mAh g –1 at 2 A g –1 . It is believed that this strategy may provide a feasible preparation of large-scale high-content silicon-based nanocomposite anodes in lithium-ion batteries.