Aging Processes in Lithiated FeSn2 Based Negative Electrode for Li-Ion Batteries: A New Challenge for Tin Based Intermetallic Materials

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• 作者：Mohamad Chamas ; Abdelfattah Mahmoud ; Junlei Tang ; Moulay Tahar Sougrati ; Stefania Panero ; Pierre-Emmanuel Lippens
• 刊名：Journal of Physical Chemistry C
• 出版年：2017
• 出版时间：January 12, 2017
• 年：2017
• 卷：121
• 期：1
• 页码：217-224
• 全文大小：463K
• ISSN：1932-7455

文摘

Tin-based intermetallic compounds proposed as negative electrode materials for Li-ion batteries not only suffer from capacity fade during cycling due to volume variations but also from aging phenomena in lithiated states. By using FeSn₂ as a model compound, we propose an analysis of this process by combining electrochemical potential measurements, ¹¹⁹Sn and ⁵⁷Fe Mössbauer spectroscopies, magnetic measurements, and impedance spectroscopy. We show that the Fe/Li₇Sn₂ composite obtained at the end of the first discharge is progressively transformed during the aging process occurring within the electrochemical cell in open circuit condition. The Fe nanoparticles are stable while the Li₇Sn₂ nanoparticles are progressively delithiated with time leading to Sn-rich Li_xSn nanoalloys without observable back reaction with Fe. The deinserted lithium atoms react with the electrolyte and modify the surface electrode interphase (SEI) by increasing its thickness and/or decreasing its porosity.