Key Laboratory of Molecular Nanostructure and Nanotechnology and Beijing National Laboratory for Molecular Science, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences , Beijing 100049, P.R. China.
University of the Chinese Academy of Sciences , Beijing 100190, P.R. China.
ACS Appl Mater Interfaces. 2017 Jul 5;9(26):22063-22067. doi: 10.1021/acsami.7b05613. Epub 2017 Jun 23.
An understanding of the formation mechanism of solid electrolyte interphase (SEI) film at the nanoscale is paramount because it is one of the key issues at interfaces in lithium-ion batteries (LIBs). Herein, we explored the nucleation, growth, and formation of SEI film on highly oriented pyrolytic graphite (HOPG) substrate in ionic liquid-based electrolytes 1-butyl-1-methyl-pyrrolidinium bis(fluorosulfonyl)imide ([BMP][FSI]) and 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide ([BMP][TFSI]) by in situ atomic force microscopy (AFM) and found that the types of anions have significant influence on the structure of the formed SEI. In [BMP][FSI] containing LiFSI, a compact and thin SEI film prefers to grow in the plane of HOPG substrate, while a rough and loose film tends to form in [BMP][TFSI] containing LiTFSI. On the basis of in situ AFM observations, the relationship between the SEI structure and the electrochemical performance was clarified.
理解固体电解质界面（SEI）膜在纳米尺度上的形成机制至关重要，因为它是锂离子电池（LIBs）界面的关键问题之一。在此，我们通过原位原子力显微镜（AFM）研究了在离子液体基电解质 1-丁基-1-甲基-吡咯烷双（氟磺酰基）亚胺（[BMP][FSI]）和 1-丁基-1-甲基吡咯烷双（三氟甲磺酰基）亚胺（[BMP][TFSI]）中，高定向石墨（HOPG）基底上 SEI 膜的成核、生长和形成，结果发现阴离子的类型对形成 SEI 的结构有显著影响。在含有 LiFSI 的 [BMP][FSI]中，SEI 膜倾向于在 HOPG 基底的平面内生长，形成致密而薄的 SEI 膜，而在含有 LiTFSI 的 [BMP][TFSI]中，形成的 SEI 膜则较为粗糙疏松。基于原位 AFM 观察，阐明了 SEI 结构与电化学性能之间的关系。
