Na-site energy of P2-type NaxM O2 (M = Mn and Co)

D. Tanabe, T. Shimono, Wataru Kobayashi, Y. Moritomo

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3 Citations (Scopus)

Abstract

P2-type NaxM O2 (M = Mn and Co) is a promising cathode material for low-cost sodium ion secondary batteries. In this structure, there are two different crystallographic Nai (i = 1 and 2) sites with different Coulomb potential $ (\varphi _i)$ provided by M4-x and O2-. Here, we experimentally determine a difference ${(\rm \Delta }\varepsilon \equiv \varepsilon _1 - \varepsilon _2)$ of Na-site energies ${(}\varepsilon _i \equiv e\varphi {\kern 1pt} _i)$ based on the temperature dependence of the site occupancies. We find that ${\rm \Delta }\varepsilon \;{=}\;56\;{K}$ for Na0.52MnO2 is significantly smaller than 190 K for Na0.59CoO2. We interpret the suppressed ${\rm \Delta }\varepsilon $ in Na0.52MnO2 in terms of the screening effect of the Na+ charge.

Original languageEnglish
Pages (from-to)1097-1101
Number of pages5
JournalPhysica Status Solidi - Rapid Research Letters
Volume7
Issue number12
DOIs
Publication statusPublished - 2013 Dec
Externally publishedYes

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Keywords

  • Crystal structure
  • Na CoO
  • Na MnO
  • Sodium ion secondary batteries
  • X-ray diffraction

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Materials Science(all)

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