Structural evolution dependency on depth-of-discharge in VO2(B) Li-ion battery electrodes

Andreas Østergaard Drejer, Bettina Pilgaard Andersen, Dorthe Bomholdt Ravnsbæk*

*Corresponding author for this work

Research output: Contribution to journal/Conference contribution in journal/Contribution to newspaperJournal articleResearchpeer-review

Abstract

Bronze vanadium oxide, VO2(B), has gained significant interest as electrode for Li-ion mainly due to the ease of preparation and the experimentally obtainable capacities of >325 mAh g−1 with intercalation of >1Li. In this work, we investigate for the first time the effects of intercalating >0.5Li on the structural phase evolution. Using operando X-ray diffraction, we find that deep discharge (i.e. inserting >0.7Li), has a dramatic effect on the subsequent charge process by introducing significant solid-solution behavior in the two-phase transition between the Li-rich and Li-poor phases. Rietveld refinement shows that the discharge-charge asymmetry is caused by severe structural deformations in the Li-rich state. Furthermore, we find that deep discharge causes capacity fade. This appears to be linked to the structural deformation causing an irreversible decrease in the Li-ion diffusion coefficients, determined herein by galvanostatic intermittent titrations.

Original languageEnglish
Article number232435
JournalJournal of Power Sources
Volume556
Number of pages10
ISSN0378-7753
DOIs
Publication statusPublished - Feb 2023

Keywords

  • Cyclic voltammetry
  • Galvanostatic intermittent titration technique
  • Li-ion batteries
  • Operando synchrotron PXRD
  • Phase transition
  • Structural distortion
  • VO(B)

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