金属电的核和生长机制
Balamurugan Thirumalraj1, Tesfaye Teka Hagos2, Chen-Jui Huang1
1Department of Chemical Engineering , National Taiwan University of Science and Technology , Taipei 10607 , Taiwan.
Journal of the American Chemical Society
|October 24, 2019
概括
一个新的Li-SEI模型量化分析了金属沉积和固体电解质间相 (SEI) 的形成. 该模型揭示了SEI断裂如何影响电池性能,以及FEC等添加剂如何提高稳定性.
科学领域:
- 材料科学
- 电化学
- 电池技术
背景情况:
- 了解 (Li) 核和生长对于开发持久且安全的离子和金属电池至关重要.
- 缺乏关于金属沉积机制的定量数据,特别是关于固体电解质间相 (SEI) 的数据.
- 在电池性能和稳定性方面,SEI层起着至关重要的作用,但其在沉积过程中的形成和断裂动态是复杂的.
研究的目的:
- 开发一种称为Li-SEI模型的定量模型,以了解Li核化和生长机制.
- 研究沉积,SEI形成和电解质分解之间的相互作用.
- 确定控制核化,生长和电解质分解的基本动力参数.
主要方法:
- 提出了Li-SEI模型,采用3D扩散控制的即时过程 (J_3D-DC) 和由于SEI断裂而导致的同时电解质减少 (J_SEI).
- 在Cu薄膜上的Li金属沉积过程中分析了各种超电位的电流.
- 确定的动力值包括扩散系数 (D),核化速率 (N0) 和SEI速率常数 (k_SEI).
主要成果:
- -SEI模型成功量化了核和增长,揭示了沉积和形成的贡献.
- 观察到J_SEI随着时间的推移而增加,这表明在沉积过程中SEI逐渐断裂.
- 发现k_SEI随着潜在的增加而增加,这表明在较高的沉积率下SEI骨折更严重,并且乙烯碳酸盐 (FEC) 添加剂显著降低k_SEI,抑制SEI骨折.
结论:
- 开发的Li-SEI模型为了解Li核化,生长和电解质分解提供了定量框架.
- SEI断裂是影响电池性能的一个重要因素,其严重程度取决于超电位.
- 乙烯碳酸盐 (FEC) 添加剂通过减轻金属沉积过程中的SEI断裂来提高电池的稳定性.
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