arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1606.06283cond-mat.mtrl-sci
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锂离子电池单晶硅电极的失效机理

Failure mechanisms of single-crystal silicon electrodes in lithium-ion batteries

Feifei Shi, Zhichao Song, Philip N. Ross, Gabor A. Somorjai, Robert O. Ritchie, Kyriakos Komvopoulos

摘要:

长期耐久性是限制锂离子电池(LIB)在重型应用和其他需要延长寿命的应用中广泛使用的主要障碍。作为电池性能退化和失效的根本原因之一,电极失效机制仍然未知。在这里,我们揭示了单晶硅电极在延长锂化/脱锂循环的基本断裂机制,使用电化学测试,微观结构表征,断裂力学和有限元分析。各向异性的锂侵入导致垂直于电极表面的裂纹萌生,随后通过电极厚度生长。锂化/未锂化硅界面的低断裂能为裂纹偏转提供了弱的微观结构路径,解释了重复循环后观察到的裂纹图案和分层。基于这种物理理解,我们展示了电解质添加剂如何修复电极裂纹,并从表面化学,电化学和材料科学的角度提供了增强未来LIB抗断裂性的策略。

英文摘要:

Long-term durability is a major obstacle limiting the widespread use of lithium ion batteries (LIBs) in heavy-duty applications and others demanding extended lifetime. As one of the root causes of degradation and failure of battery performance, the electrode failure mechanisms are still unknown. Here, we reveal the fundamental fracture mechanisms of single-crystal silicon electrodes over extended lithiation/delithiation cycles, using electrochemical testing, microstructure characterization, fracture mechanics, and finite element analysis. Anisotropic lithium invasion causes crack initiation perpendicular to the electrode surface, followed by growth through the electrode thickness. The low fracture energy of the lithiated/unlithiated silicon interface provides a weak microstructural path for crack deflection, accounting for the crack patterns and delamination observed after repeated cycling. Based on this physical understanding, we demonstrate how electrolyte additives can heal electrode cracks and provide strategies to enhance the fracture resistance in future LIBs from surface chemical, electrochemical, and material science perspectives.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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