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This content will become publicly available on March 17, 2019

Title: Effect of overcharge on Li(Ni 0.5Mn 0.3Co 0.2)O 2/Graphite lithium ion cells with poly(vinylidene fluoride) binder. I - Microstructural changes in the anode

Cells based on NMC/graphite, containing poly(vinylidene difluoride) (PVDF) binders in the positive and negative electrodes, were systematically overcharged to 100, 120, 140, 160, 180, and 250% state-of-charge (SOC). At 250% SOC the cell vented. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) of the anodes showed several state-of-overcharge-dependent trends. Starting at 120% SOC, dendrites appeared and increased in concentration as the SOC increased. Dendrite morphology appeared to be dependent on whether the active material was on the “dull” or “shiny” side of the copper collector. Significantly more delamination of the active material from the collector was seen on the “shiny” side of the collector particularly at 180 and 250% SOC. Transition metals were detected at 120% SOC and increased in concentration as the SOC increased. Finally, there was considerable spatial heterogeneity in the microstructures across each laminate with several regions displaying complex layered structures.
Authors:
 [1] ;  [1] ; ORCiD logo [2] ; ORCiD logo [2] ; ORCiD logo [2] ;  [3] ;  [3] ;  [3] ;  [3] ;  [3] ;  [1]
  1. Argonne National Lab. (ANL), Argonne, IL (United States). Chemical Sciences and Engineering Division
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Energy and Transportation Science Division
  3. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Power Sources Technology Group
Publication Date:
Grant/Contract Number:
AC05-00OR22725; AC02-06CH11357; NA0003525
Type:
Accepted Manuscript
Journal Name:
Journal of Power Sources
Additional Journal Information:
Journal Volume: 385; Journal Issue: C; Journal ID: ISSN 0378-7753
Publisher:
Elsevier
Research Org:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Vehicle Technologies Office (EE-3V); USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
Language:
English
Subject:
25 ENERGY STORAGE; Lithium-ion battery; Overcharge; Scanning electron microscopy; Microstructure; SEI; Anode
OSTI Identifier:
1439931