Space matters : Li+ conduction versus strain effect at FePO4/LiFePO4 interface

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

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Author(s)

  • Weiqiang Lv
  • Yinghua Niu
  • Xian Jian
  • Kelvin H. L. Zhang
  • Wei Wang
  • Zhiming Wang
  • Weiqing Yang
  • Weidong He

Detail(s)

Original languageEnglish
Article number83901
Journal / PublicationApplied Physics Letters
Volume108
Issue number8
Publication statusPublished - 22 Feb 2016

Link(s)

Abstract

FePO4/LiFePO4 (FP/LFP) interfacial strain, giving rise to substantial variation in interfacial energy and lattice volume, is inevitable in the (de)lithiation process of LiFePO4, a prototype of Li ion battery cathodes. Extensive theoretical and experimental research has been focused on the effect of lattice strain energy on FP/LFP interface propagation orientation and cyclic stability of the electrode. However, the essential effect of strain induced lattice distortion on Li+ transport at the FP/LFP interface is typically overlooked. In this report, a coherent interface model is derived to evaluate quantitatively the correlation between FP/LFP lattice distortion and Li+ conduction. The results illustrate that the effect of lattice strain on Li+ conduction depends strongly on FP/LFP interface orientations. Lattice strain induces a 90% decrease of Li+ conductivity in ac-plane oriented (de)lithiation at room temperature. The opposite effect of lattice strain on delithiation and lithiation for ab-and bc-orientations is elucidated. In addition, the effect of lattice strain tends to be more pronounced at a lower working temperature. This study provides an efficient platform to comprehend and manipulate Li+ conduction in the charge and discharge of lithium ion batteries, the large-scale application of which is frequently challenged by limited in-cell ion conduction.

Research Area(s)

Citation Format(s)

Space matters: Li+ conduction versus strain effect at FePO4/LiFePO4 interface. / Lv, Weiqiang; Niu, Yinghua; Jian, Xian et al.
In: Applied Physics Letters, Vol. 108, No. 8, 83901, 22.02.2016.

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

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