Magnetism in lithium-oxygen discharge product

Jun Lu, Hun Ji Jung, Kah Chun Lau, Zhengcheng Zhang, John A. Schlueter, Peng Du, Rajeev S. Assary, Jeffrey Greeley, Glen A. Ferguson, Hsien Hau Wang, Jusef Hassoun, Hakim Iddir, Jigang Zhou, Lucia Zuin, Yongfeng Hu, Yang Kook Sun, Bruno Scrosati, Larry A. Curtiss, Kahlil Amine

Research output: Contribution to journalArticlepeer-review

18 Scopus citations

Abstract

Nonaqueous lithium-oxygen batteries have a much superior theoretical gravimetric energy density compared to conventional lithium-ion batteries, and thus could render long-range electric vehicles a reality. A molecular-level understanding of the reversible formation of lithium peroxide in these batteries, the properties of major/minor discharge products, and the stability of the nonaqueous electrolytes is required to achieve successful lithium-oxygen batteries. We demonstrate that the major discharge product formed in the lithium-oxygen cell, lithium peroxide, exhibits a magnetic moment. These results are based on dc-magnetization measurements and a lithium-oxygen cell containing an ether-based electrolyte. The results are unexpected because bulk lithium peroxide has a significant band gap. Density functional calculations predict that superoxide-type surface oxygen groups with unpaired electrons exist on stoichiometric lithium peroxide crystalline surfaces and on nanoparticle surfaces; these computational results are consistent with the magnetic measurement of the discharged lithium peroxide product as well as EPR measurements on commercial lithium peroxide. The presence of superoxide-type surface oxygen groups with spin can play a role in the reversible formation and decomposition of lithium peroxide as well as the reversible formation and decomposition of electrolyte molecules. In a spin: The major discharge product formed in the lithium-oxygen cell, lithium peroxide, exhibits a magnetic moment. Density functional calculations predict that "superoxide-like" surface oxygen groups with unpaired electrons exist on nanoparticle surfaces, consistent with magnetic measurements of discharged lithium peroxide products. The "superoxide-like" surface oxygen groups with spin can play a role in the reversible formation and decomposition of lithium peroxide as well as electrolyte molecules.

Original languageEnglish (US)
Pages (from-to)1196-1202
Number of pages7
JournalChemSusChem
Volume6
Issue number7
DOIs
StatePublished - Jul 2013

Keywords

  • batteries
  • density functional calculations
  • lithium peroxide
  • magnetic properties
  • superoxide

ASJC Scopus subject areas

  • Environmental Chemistry
  • Chemical Engineering(all)
  • Materials Science(all)
  • Energy(all)

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