Does Spinel Serve as a Rigid Framework for Oxygen Redox?

Xiang Mei Shi, Eriko Watanabe, Masashi Okubo, Atsuo Yamada*

*この研究の対応する著者

研究成果: Article査読

抄録

The oxygen-redox chemistry of lithium-rich layered transition-metal oxides has recently paved a path for the development of large-capacity positive electrode materials. Although oxygen-redox activity typically arises from the labile 2p states of undercoordinated oxide ions, the instability of layered structures after extracting excess Li ions often leads to transformation to a spinel structure, causing capacity fading and voltage decay after charge/discharge cycles. In this work, we perform density functional theory calculations to determine the oxygen-redox activity of spinel LiMg0.5Mn1.5O4 in an attempt to discover a robust three-dimensional framework for oxygen-redox reactions. The presence of ionic Mg2+ in the framework results in labile O 2p states for oxygen-redox activity. However, in contrast with the dominant Mn-O interactions that could stabilize oxidized oxide ions in a typical lithium-rich layered oxide Li2MnO3, spinel LiMg0.5Mn1.5O4 is dominated by O-O interactions near the Fermi level, which are less able to stabilize holes, leading to decomposition reactions that include release of oxygen gas.

本文言語English
ページ(範囲)7181-7187
ページ数7
ジャーナルChemistry of Materials
32
17
DOI
出版ステータスPublished - 2020 9 8
外部発表はい

ASJC Scopus subject areas

  • 化学 (全般)
  • 化学工学(全般)
  • 材料化学

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