Multiorbital bond formation for stable oxygen-redox reaction in battery electrodes

Takaaki Sudayama, Kazuki Uehara, Takahiro Mukai, Daisuke Asakura, Xiang Mei Shi, Akihisa Tsuchimoto, Benoit Mortemard De Boisse, Tatau Shimada, Eriko Watanabe, Yoshihisa Harada, Masanobu Nakayama, Masashi Okubo, Atsuo Yamada*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)

Abstract

High-energy-density batteries have been a long-standing target toward sustainability, but the energy density of state-of-the-art lithium-ion batteries is limited in part by the small capacity of the positive electrode materials. Although employing the additional oxygen-redox reaction of Li-excess transition-metal oxides is an attractive approach to increase the capacity, an atomic-level understanding of the reaction mechanism has not been established so far. Here, using bulk-sensitive resonant inelastic X-ray scattering spectroscopy combined with ab initio computations, we demonstrate the presence of a localized oxygen 2p orbital weakly hybridized with transition metal t2g orbitals that was theoretically predicted to play a key role in oxygen-redox reactions. After oxygen oxidation, the hole in the oxygen 2p orbital is stabilized by the generation of either a (σ + π) multiorbital bond through strong π back-donation or peroxide O22- through oxygen dimerization. The multiorbital bond formation with σ-accepting and π-donating transition metals can thus lead to reversible oxygen-redox reaction.

Original languageEnglish
Pages (from-to)1492-1500
Number of pages9
JournalEnergy and Environmental Science
Volume13
Issue number5
DOIs
Publication statusPublished - 2020
Externally publishedYes

ASJC Scopus subject areas

  • Environmental Chemistry
  • Renewable Energy, Sustainability and the Environment
  • Nuclear Energy and Engineering
  • Pollution

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