Study of local disorder in LiMn(Cr,Ni)O2 compounds by extended X-ray absorption fine structure measurements

L. Maugeri, A. Iadecola, L. Simonelli, G. Chen, H. Wadati, T. Mizokawa, N. L. Saini

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

We have studied local structure of LiMnO2, LiMn 0.65Cr0.35O2 and LiMn0.5Ni 0.5O2 compounds by Mn K-edge extended X-ray absorption fine structure measurements. The local structure of LiMnO2 is found to be consistent with Jahn-Teller distorted MnO6 octahedra characterized by two different Mn-O bond distances. The Jahn-Teller distortions are suppressed in the Cr and Ni substituted compounds, resulting a single Mn-O distance. However, the Cr atoms tend to occupy a site at a longer distance from Mn in the host lattice (Mn-Cr distance is longer than Mn-Mn distance), unlike the Ni atoms which prefer a site closer to the Mn atoms (Mn-Ni distance is shorter than Mn-Mn distance). Incidentally, Mn-O and Mn-Mn bonds are substantially stiffer in the Cr and Ni substituted compounds. In addition, the static atomic disorder is confined around Cr atoms in the LiMn 0.65Cr0.35O2, that is different from the case of LiMn0.5Ni0.5O2 in which larger static disorder appears in the proximity of the Mn atoms. The results suggest that the differences in the local structure of different compounds should be the likely reason for their differing battery characteristics.

Original languageEnglish
Pages (from-to)202-207
Number of pages6
JournalJournal of Power Sources
Volume242
DOIs
Publication statusPublished - 2013 Jun 24
Externally publishedYes

Keywords

  • Disordered solids
  • Lithium-ion batteries
  • Local disorder
  • X-ray absorption spectroscopy

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Energy Engineering and Power Technology
  • Physical and Theoretical Chemistry
  • Electrical and Electronic Engineering

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