Dynamic Molecular Investigation of the Solid-Electrolyte Interphase of an Anode-Free Lithium Metal Battery Using In Situ Liquid SIMS and Cryo-TEM

Cuixia Cheng; Yadong Zhou; Yaobin Xu; Hao Jia; Jumyeong Kim; Wu Xu; Chongmin Wang; Peiyuan Gao; Zihua Zhu

doi:10.1021/acs.nanolett.3c00709

Dynamic Molecular Investigation of the Solid-Electrolyte Interphase of an Anode-Free Lithium Metal Battery Using In Situ Liquid SIMS and Cryo-TEM

Nano Lett. 2023 Sep 27;23(18):8385-8391. doi: 10.1021/acs.nanolett.3c00709. Epub 2023 Sep 13.

Authors

Cuixia Cheng^{1

2}, Yadong Zhou², Yaobin Xu², Hao Jia³, Jumyeong Kim³, Wu Xu³, Chongmin Wang², Peiyuan Gao⁴, Zihua Zhu²

Affiliations

¹ Hubei Key Laboratory of Pollutant Analysis & Reuse Technology, College of Chemistry and Chemical Engineering, Hubei Normal University, Huangshi, Hubei 435002, China.
² Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99354, United States.
³ Energy and Environmental Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354, United States.
⁴ Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99354, United States.

PMID: 37703459
DOI: 10.1021/acs.nanolett.3c00709

Abstract

We use in situ liquid secondary ion mass spectroscopy, cryogenic transmission electron microscopy, and density functional theory calculation to delineate the molecular process in the formation of the solid-electrolyte interphase (SEI) layer under the dynamic operating conditions. We discover that the onset potential for SEI layer formation and the thickness of the SEI show dependence on the solvation shell structure. On a Cu film anode, the SEI is noticed to start to form at around 2.0 V (nominal cell voltage) with a final thickness of about 40-50 nm in the 1.0 M LiPF₆/EC-DMC electrolyte, while for the case of 1.0 M LiFSI/DME, the SEI starts to form at around 1.5 V with a final thickness of about 20 nm. Our observations clearly indicate the inner and outer SEI layer formation and dissipation upon charging and discharging, implying a continued evolution of electrolyte structure with extended cycling.

Keywords: anode-free lithium metal battery; cryogenic transmission electron microscopy; density functional theory; in situ liquid secondary ion mass spectroscopy; molecular signature; solid-electrolyte interphase layer.