Sodium ion diffusion in layered NaxCoO2

Takayuki Shibata, Wataru Kobayashi, Yutaka Moritomo

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Abstract

The temperature dependence of sodium ion diffusion coefficient (D) of NaxCoO2 is extensively investigated in the temperature range of 303 ≤ T ≤ 349 K using electrochemical impedance spectroscopy. The magnitude of D is found to be (0:7-1:9) × 10-11 cm 2/s (0:54 ≤ x ≤ 0:85) at 303 K, which is comparable to that of LiCoO2. The activation energy (ED a ) of D gradually increases from 0.32 at x = 0:54 to 0.51 eV at x = 0:85. The activation energy (ER a ) of charge-transfer resistance (R ct) also increases from 0.34 at x = 0:54 to 0.59 eV at x = 0:85. These behaviors are ascribed to an increase in potential barrier due to the decrease in interlayer distance (d).

Original languageEnglish
Article number097101
JournalApplied Physics Express
Volume6
Issue number9
DOIs
Publication statusPublished - 2013 Sep
Externally publishedYes

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ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy(all)

Cite this

Shibata, T., Kobayashi, W., & Moritomo, Y. (2013). Sodium ion diffusion in layered NaxCoO2 . Applied Physics Express, 6(9), [097101]. https://doi.org/10.7567/APEX.6.097101