Surface Coating Constraint Induced Anisotropic Swelling of Silicon in Si–Void@SiO x Nanowire Anode for Lithium‐Ion Batteries

• Published in: Small (Weinheim an der Bergstrasse, Germany) Germany), 2017-04, Vol.13 (13), p.n/a
• Main Authors: Liu, Qian, Cui, Zhe, Zou, Rujia, Zhang, Jianhua, Xu, Kaibing, Hu, Junqing
• Format: Article
• Language: English
• Subjects: anisotropic swelling; anodes; cycling stability; Si–void@SiOx nanowires; surface coating constraint, lithium‐ion batteries
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.201603754

Here a simple and an environmentally friendly approach is developed for the fabrication of Si–void@SiOx nanowires of a high‐capacity Li‐ion anode material. The outer surface of the robust SiOx backbone and the inside void structure in Si–void@SiOx nanowires appropriately suppress the volume expansion and lead to anisotropic swelling morphologies of Si nanowires during lithiation/delithiation, which is first demonstrated by the in situ lithiation process. Remarkably, the Si–void@SiOx nanowire electrode exhibits excellent overall lithium‐storage performance, including high specific capacity, high rate property, and excellent cycling stability. A reversible capacity of 1981 mAh g−1 is obtained in the fourth cycle, and the capacity is maintained at 2197 mAh g−1 after 200 cycles at a current density of 0.5 C. The outstanding overall properties of the Si–void@SiOx nanowire composite make it a promising anode material of lithium‐ion batteries for the power‐intensive energy storage applications. The Si–void@SiOx nanowire anode is designed by a simple synthetic and environmentally friendly process, and in situ investigation of lithiated Si–void@SiOx nanowire is performed inside a transmission electron microscope. Si–void@SiOx nanowire electrodes exhibit improved lithium storage properties including the high specific capacity and high rate capability.