Resolving the Discrepancy in Tortuosity Factor Estimation for Li-Ion Battery Electrodes through Micro-Macro Modeling and Experiment

Francois Usseglio Viretta, Andrew Colclasure, Donal Finegan, Kandler Smith, Kofi Yao Claver, Daniel Abraham, Ashutosh Mistry, Partha Mukherjee, Thomas Heenan, Paul Shearing, Fezzeh Pouraghajan, Dean Wheeler, Samuel Cooper

Research output: Contribution to journalArticlepeer-review

139 Scopus Citations

Abstract

Battery performance is strongly correlated with electrode microstructural properties. Of the relevant properties, the tortuosity factor of the electrolyte transport paths through microstructure pores is important as it limits battery maximum charge/discharge rate, particularly for energy-dense thick electrodes. Tortuosity factor however, is difficult to precisely measure, and thus its estimation has been debated frequently in the literature. Herein, three independent approaches have been applied to quantify the tortuosity factor of lithium-ion battery electrodes. The first approach is a microstructure model based on three-dimensional geometries from X-ray computed tomography (CT) and stochastic reconstructions enhanced with computationally generated carbon/binder domain (CBD), as CT is often unable to resolve the CBD. The second approach uses a macro-homogeneous model to fit electrochemical data at several rates, providing a separate estimation of the tortuosity factor. The third approach experimentally measures tortuosity factor via symmetric cells employing a blocking electrolyte. Comparisons have been made across the three approaches for 14 graphite and nickel-manganese-cobalt oxide electrodes. Analysis suggests that if the tortuosity factor were characterized based on the active material skeleton only, the actual tortuosities would be 1.35–1.81 times higher for calendered electrodes. Correlations are provided for varying porosity, CBD phase interfacial arrangement and solid particle morphology.

Original languageAmerican English
Pages (from-to)A3403-A3426
JournalJournal of the Electrochemical Society
Volume165
Issue number14
DOIs
StatePublished - 2018

Bibliographical note

Publisher Copyright:
© The Author(s) 2018. Published by ECS.

NREL Publication Number

  • NREL/JA-5400-71184

Keywords

  • calendaring
  • carbon/binder domain arrangement
  • electrode tortuosity
  • graphite
  • lithium-ion battery
  • macro homogeneous model
  • microstructure model
  • nickel-cobalt-manganese
  • stochastic microstructure

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