論文

査読有り
2020年5月7日

Arrangement in La1/3NbO3 Obtained by First-Principles Density Functional Theory with Cluster Expansion and Monte Carlo Simulation

The Journal of Physical Chemistry C
  • Zijian Yang
  • ,
  • Robyn E. Ward
  • ,
  • Naoto Tanibata
  • ,
  • Hayami Takeda
  • ,
  • Masanobu Nakayama
  • ,
  • Toru Asaka

124
18
開始ページ
9746
終了ページ
9754
記述言語
英語
掲載種別
研究論文(学術雑誌)
DOI
10.1021/acs.jpcc.0c01350
出版者・発行元
American Chemical Society ({ACS})

LixLa(1-x)/3NbO3 is an A-site-deficient perovskite material that exhibits structure-dependent ionic conductivity. La1/3NbO3 has a larger unit cell volume, lower concentration of La3+ ions, and higher concentration of intrinsic vacancies than La2/3TiO3. As such, it should exhibit higher Li ion conductivity and, therefore, be a good candidate for all ceramic Li secondary batteries or fast Li ion transport solid-state electrolyte batteries. However, experimental observations show otherwise. Information on the local atomic arrangements would facilitate the analysis of the gap between the theoretical and experimental results. Ab initio density functional theory calculations are useful for calculating the atomic arrangements and energies. However, because of cell size limitations, long-range ordering in La/Li/vacancy arrangements cannot be observed using ab initio calculations. In this study, cluster expansion and Monte Carlo simulations were utilized to bridge this gap. The computational results reproduce the stacking of alternate La-rich and La-poor layers along the c-axis, consistent with the experimental data. In addition, two possible modulated structures for the La-rich layers were discovered. These should help explain the lower-than-expected ionic conductivity and the possible Li ion migration pathways in the material. Based on the presented Monte Carlo simulations, we conclude that the two types of low-energy structures, the closed and striped arrangements, may coexist in the real system. The modulated structures in experimental studies are likely to be numberless nanodomains composed of these two arrangements. If the majority of the structure shows a closed arrangement at room temperature, most of the Li ions will be trapped at the center of the periodic units in the closed arrangement. This could explain the lower-than-expected Li ion conductivity in LixLa(1-x)/3NbO3.


リンク情報
DOI
https://doi.org/10.1021/acs.jpcc.0c01350
Web of Science
https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000535175400013&DestApp=WOS_CPL

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