Microscopic Origin of the Solid Electrolyte Interphase Formation in Fire-Extinguishing Electrolyte: Formation of Pure Inorganic Layer in High Salt Concentration
Microscopic Origin of the Solid Electrolyte Interphase Formation in Fire-Extinguishing Electrolyte: Formation of Pure Inorganic Layer in High Salt Concentration
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DOI：
10.1021/acs.jpclett.9b02392
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发表时间：
2019-10-03
影响因子：
5.7
通讯作者：
Nagaoka, Masataka
中科院分区：
文献类型：
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作者：
Bouibes, Amine;Takenaka, Norio;Nagaoka, Masataka
基于不可燃溶剂磷酸三甲酯（TMP）的高盐浓度（HC）电解质最近显示出除了优异的充放电性能之外的有吸引力的自熄特性。然而，其固体电解质界面（SEI）层的微观理解仍然是一个悬而未决的问题。在这封信中，红月亮（RM）方法被用来研究依赖于TMP基电解质中双（氟磺酰基）氨基锂（LiFSA）盐浓度的SEI层形成的分子机制，并且能够成功地再现实验观察结果，即，“自下而上”的形成机制，具有主要基于HC电解质中的盐还原的更薄且更致密的SEI层。结果表明，在HC电解质中形成纯致密的无机层，这将显著改善SEI层稳定性，从而导致充电-放电性能的更长寿命。这一新的微观发现将为设计有效的不可燃电解质以开发先进、安全的二次电池提供重要指导。
A highly salt-concentrated (HC) electrolyte based on the nonflammable solvent trimethyl-phosphate (TMP) has recently shown an attractive self-extinguishing property in addition to an excellent charge-discharge performance. However, the microscopic understanding of its solid electrolyte interphase (SEI) layer remains an open question. In this Letter, the red moon (RM) method was used to investigate the molecular mechanism of SEI layer formation depending on lithium bis(fluorosulfonyl)amide (LiFSA) salt concentration in a TMP-based electrolyte and was able to reproduce successfully the experimental observations, i.e., the "bottom-up" formation mechanism with a thinner and denser SEI layer mainly based on salt reduction in the HC electrolyte. The results showed that a pure dense inorganic layer is formed in the HC electrolyte, which should considerably improve the SEI layer stability leading to a longer lifetime in charge-discharge performance. This new microscopic finding should provide an important guide in designing an effective nonflammable electrolyte to develop advanced, safe secondary batteries.