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Title: Three-Phase 3D Reconstruction of a LiCoO 2 Cathode via FIB-SEM Tomography

Three-phase three-dimensional (3D) microstructural reconstructions of lithium-ion battery electrodes are critical input for 3D simulations of electrode lithiation/delithiation, which provide a detailed understanding of battery operation. In this report, 3D images of a LiCoO 2electrode are achieved using focused ion beam-scanning electron microscopy (FIB-SEM), with clear contrast among the three phases: LiCoO 2particles, carbonaceous phases (carbon and binder) and the electrolyte space. The good contrast was achieved by utilizing an improved FIB-SEM sample preparation method that combined infiltration of the electrolyte space with a low-viscosity silicone resin and triple ion-beam polishing. Morphological parameters quantified include phase volume fraction, surface area, feature size distribution, connectivity, and tortuosity. Electrolyte tortuosity was determined using two different geometric calculations that were in good agreement. In conclusion, the electrolyte tortuosity distribution versus position within the electrode was found to be highly inhomogeneous; this will lead to inhomogeneous electrode lithiation/delithiation at high C-rates that could potentially cause battery degradation.
Authors:
ORCiD logo [1] ;  [2] ;  [2] ;  [1] ;  [1]
  1. Northwestern Univ., Evanston, IL (United States). Department of Materials Science and Engineering
  2. Brookhaven National Lab. (BNL), Upton, NY (United States). Photon Science Directorate
Publication Date:
Report Number(s):
BNL-112534-2016-JA
Journal ID: ISSN 1431-9276
Grant/Contract Number:
SC00112704
Type:
Accepted Manuscript
Journal Name:
Microscopy and Microanalysis
Additional Journal Information:
Journal Volume: 22; Journal Issue: 1; Journal ID: ISSN 1431-9276
Publisher:
Microscopy Society of America (MSA)
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
25 ENERGY STORAGE; 36 MATERIALS SCIENCE; Li-ion batteries; three-phase 3D reconstruction; FIB-SEM tomography; cathode; microstructure
OSTI Identifier:
1340376