학술논문
Visualization and Chemical Characterization of the Cathode Electrolyte Interphase Using He-Ion Microscopy and In Situ Time-of-Flight Secondary Ion Mass Spectrometry.
Document Type
Academic Journal
Author
Wheatcroft L; Department of Materials Science and Engineering, University of Sheffield, Mappin Street, Sheffield S1 3JD, U.K.; Klingner N; Helmholtz Zentrum Dresden-Rossendorf, Bautzner Landstraβe 400, Dresden 01328, Germany.; Heller R; Helmholtz Zentrum Dresden-Rossendorf, Bautzner Landstraβe 400, Dresden 01328, Germany.; Hlawacek G; Helmholtz Zentrum Dresden-Rossendorf, Bautzner Landstraβe 400, Dresden 01328, Germany.; Özkaya D; Johnson Matthey Technology Centre, Blounts Ct Road, Sonning Common, Reading RG4 9NH, U.K.; Cookson J; Johnson Matthey Technology Centre, Blounts Ct Road, Sonning Common, Reading RG4 9NH, U.K.; Inkson BJ; Department of Materials Science and Engineering, University of Sheffield, Mappin Street, Sheffield S1 3JD, U.K.
Source
Publisher: American Chemical Society Country of Publication: United States NLM ID: 101718976 Publication Model: Print-Electronic Cited Medium: Internet ISSN: 2574-0962 (Electronic) NLM ISO Abbreviation: ACS Appl Energy Mater Subsets: PubMed not MEDLINE
Subject
Language
English
Abstract
Unstable cathode electrolyte interphase (CEI) formation increases degradation in high voltage Li-ion battery materials. Few techniques couple characterization of nano-scale CEI layers on the macroscale with in situ chemical characterization, and thus, information on how the underlying microstructure affects CEI formation is lost. Here, the process of CEI formation in a high voltage cathode material, LiCoPO 4 , has been investigated for the first time using helium ion microscopy (HIM) and in situ time-of-flight (ToF) secondary ion mass spectrometry (SIMS). The combination of HIM and Ne-ion ToF-SIMS has been used to correlate the cycle-dependent morphology of the CEI layer on LiCoPO 4 with a local cathode microstructure, including position, thickness, and chemistry. HIM imaging identified partial dissolution of the CEI layer on discharge resulting in in-homogenous CEI coverage on larger LiCoPO 4 agglomerates. Ne-ion ToF-SIMS characterization identified oxyfluorophosphates from HF attack by the electrolyte and a Li-rich surface region. Variable thickness of the CEI layer coupled with inactive Li on the surface of LiCoPO 4 electrodes contributes to severe degradation over the course of 10 cycles. The HIM-SIMS technique has potential to further investigate the effect of microstructures on CEI formation in cathode materials or solid electrolyte interphase formation in anodes, thus aiding future electrode development.
Competing Interests: The authors declare no competing financial interest.
(Copyright © 2020 American Chemical Society.)
Competing Interests: The authors declare no competing financial interest.
(Copyright © 2020 American Chemical Society.)