In situ TEM visualization of LiF nanosheet formation on the cathode-electrolyte interphase (CEI) in liquid-electrolyte lithium-ion batteries

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

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Detail(s)

Original languageEnglish
Pages (from-to)1235-1250
Journal / PublicationMatter
Volume5
Issue number4
Online published7 Feb 2022
Publication statusPublished - 6 Apr 2022

Abstract

The formation behaviors of LiF nanocrystals have been studied on anodes in Li-ion batteries; there is no research work reporting LiF crystal growth on cathodes. Here, we report a real-time LiF crystal formation on positively charged titanium (Ti) electrodes in an electrochemical liquid cell with 150-nm-thick Li hexafluorophosphate (LiPF6)/propylene carbonate (PC) liquid electrolyte loaded. The LiF nanocrystals show two-dimensional (2D) morphologies on the electrode surface, which can serve as a cathode electrolyte interface (CEI). Furthermore, the merging of LiF nanosheets was also observed, which may underlie the self-healing ability of LiF-based CEIs. Theoretical modeling indicates that there are two types of LiF formation paths on positive voltage-biased Ti electrodes. This work shows the remarkable morphing mobility and self-healing ability of LiF nanosheets and sheds light on strategies of modulating LiF nanocrystals and cathode surface chemistry for improving battery performance and cycle life.

Research Area(s)

  • cathode-electrolyte interphase, CEI, electrochemical liquid cell, in situ TEM, LiF nanocrystals, lithium-ion batteries

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