Lithium-Assisted Electrochemical Welding in Silicon Nanowire Battery Electrodes

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• 作者：Khim Karki ; Eric Epstein ; Jeong-Hyun Cho ; Zheng Jia ; Teng Li ; S. Tom Picraux ; Chunsheng Wang ; John Cumings
• 刊名：Nano Letters
• 出版年：2012
• 出版时间：March 14, 2012
• 年：2012
• 卷：12
• 期：3
• 页码：1392-1397
• 全文大小：264K
• 年卷期：v.12,no.3(March 14, 2012)
• ISSN：1530-6992

文摘

From in situ transmission electron microscopy (TEM) observations, we present direct evidence of lithium-assisted welding between physically contacted silicon nanowires (SiNWs) induced by electrochemical lithiation and delithiation. This electrochemical weld between two SiNWs demonstrates facile transport of lithium ions and electrons across the interface. From our in situ observations, we estimate the shear strength of the welded region after delithiation to be approximately 200 MPa, indicating that a strong bond is formed at the junction of two SiNWs. This welding phenomenon could help address the issue of capacity fade in nanostructured silicon battery electrodes, which is typically caused by fracture and detachment of active materials from the current collector. The process could provide for more robust battery performance either through self-healing of fractured components that remain in contact or through the formation of a multiconnected network architecture.

Keywords:

Silicon nanowires; welding; self-healing; interfacial lithium diffusivity; in situ TEM; lithium-ion battery