Peroxo Species Formed in the Bulk of Silicate Cathodes

Zhenlian Chen, Bjoern Schwarz, Xianhui Zhang, Wenqiang Du, Lirong Zheng, Ailing Tian, Ying Zhang, Zhiyong Zhang, Xiao Cheng Zeng, Zhifeng Zhang, Liyuan Huai, Jinlei Wu, Helmut Ehrenberg, Deyu Wang, Jun Li

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Oxygen redox in Li-rich oxides may boost the energy density of lithium-ion batteries by incorporating oxygen chemistry in solid cathodes. However, oxygen redox in the bulk usually entangles with voltage hysteresis and oxygen release, resulting in a prolonged controversy in literature on oxygen transformation. Here, we report spectroscopic evidence of peroxo species formed and confined in silicate cathodes amid oxygen redox at high voltage, accompanied by Co2+/Co3+ redox dominant at low voltage. First-principles calculations reveal that localized electrons on dangling oxygen drive the O-O dimerization. The covalence between the binding cation and the O-O dimer determines the degree of electron transfer in oxygen transformation. Dimerization induces irreversible structural distortion and slow kinetics. But peroxo formation can minimize the voltage drop and volume expansion in cumulative cationic and anionic redox. These findings offer insights into oxygen redox in the bulk for the rational design of high-energy-density cathodes.

Original languageEnglish (US)
Pages (from-to)10056-10063
Number of pages8
JournalAngewandte Chemie - International Edition
Volume60
Issue number18
DOIs
StatePublished - Apr 26 2021

Keywords

  • X-ray spectroscopy
  • ab initio calculations
  • lithium-ion batteries
  • oxygen redox
  • peroxo formation

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)

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