Multi-length scale microstructural design of lithium-ion battery electrodes for improved discharge rate performance

Xuekun Lu, Xun Zhang, Chun Tan, Thomas M.M. Heenan, Marco Lagnoni, Kieran O'Regan, Sohrab Daemi, Antonio Bertei, Helen G. Jones, Gareth Hinds, Juyeon Park, Emma Kendrick, Dan J.L. Brett, Paul R. Shearing

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

Fast discharge capability of automotive batteries not only affects the acceleration and climbing performance of electric vehicles, but also the accessible driving range under complex driving cycles. Understanding the intricate physical and chemical processes across multiple length-scales is critical to assist the strategic design of electrodes for improved rate performance. Here, we correlate the discharge rate performance of Ni-rich LiNi1-x-yCoxMnyO2 (NMC) cathodes to the electrode architectures, ranging from the crystallographic orientations, surface morphology and cracks at single particle level, to the factors that affect the dominance of the solid and liquid-state transport (SST and LST) at electrode level. A random orientation of the primary particles is found to incur an increase of the SST resistance by a factor of 2.35 at 5C and a heterogeneous intra-particle lithiation. Internal cracks significantly restrict the accessibility to the active material. Double-layered particles are proved to be a more promising candidate than single-crystal particles. At electrode level, the SST-dominance depth is quantified for the first time to guide the microstructural tuning and rational operating windows are proposed for electrodes of various architectures. The reaction front is observed to shuttle across the electrode depth to mitigate the polarization, which can provide valuable insights into the battery management development. Finally, by comparing the performance of single crystal and polycrystalline NMC811 electrodes, it is suggested that electrode thickness and porosity are more critical in the former for enhanced discharge rate performance, in contrast to polycrystalline electrodes, in which a gradient particle fraction and size distribution are recommended.

Original languageEnglish
Pages (from-to)5929-5946
Number of pages18
JournalEnergy and Environmental Science
Volume14
Issue number11
Early online date17 Sep 2021
DOIs
Publication statusPublished - 1 Nov 2021

Bibliographical note

Funding Information:
This work was supported by the Engineering and Physical Sciences Research Council [EP/R020973/1, EP/M028100/1]; and the Faraday Institution (Faraday.ac.uk; EP/S003053/1, grant numbers FIRG003, FIRG001 and FIRG015). P. R. S. acknowledges funding from the Royal Academy of Engineering (CiET1718\59). X. L., J. P. and G. H. acknowledge support from the National Measurement System of the UK Department of Business, Energy and Industrial Strategy. A. B. and M. L. acknowledge support from the Universitàdi Pisa under the ‘‘PRA–Progetti di Ricerca di Ateneo’’ (Institutional Research Grants)–Project no. PRA_2020-2021_48.

Publisher Copyright:
© 2021 The Royal Society of Chemistry.

ASJC Scopus subject areas

  • Environmental Chemistry
  • Renewable Energy, Sustainability and the Environment
  • Nuclear Energy and Engineering
  • Pollution

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