Expanded lithiation of titanium disulfide: Reaction kinetics of multi-step conversion reaction

Maosen Fu, Zhenpeng Yao, Xiao Ma, Hui Dong, Ke Sun, Sooyeon Hwang, Enyuan Hu, Hong Gan, Yan Yao, Eric A. Stach, Chris Wolverton, Dong Su*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


Phase evolution during a thorough Li ion's insertion of electrode materials governs their battery performance during charge and discharge. Here we investigated the lithiation pathway of titanium disulfide using in situ TEM combined with synchrotron-based pair distribution function measurement and first-principles calculations. A 2D intercalation reaction proceeds along with a transition from van der Waals interaction between Ti–S slabs to the covalent bonding of S–Li–S, with no symmetry broken. Further lithiation triggers unconventionally multiple step conversion reactions as proved: LiTiS2→TiS→Ti2S→Ti. The conversion reaction pathway is also verified in fully discharged sample in coin-cell. The expanded conversion chemistry is supposed to increase the capacity of TiS2 electrode and downgrade the cyclability, whereas the existence of intermediate phases shows the promise of improving the reversibility with a successful control of the state of charge.

Original languageEnglish (US)
Article number103882
JournalNano Energy
StatePublished - Sep 2019


  • 2D metal chalcogenides
  • Conversion reaction
  • In situ transmission electron microscopy
  • Lithiation
  • Lithium ion battery

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Materials Science(all)
  • Electrical and Electronic Engineering


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