Origin of the Overpotential for the Oxygen Evolution Reaction on a Well-Defined Graphene Electrode Probed by in Situ Sum Frequency Generation Vibrational Spectroscopy

Qiling Peng, Jiafeng Chen, Hengxing Ji, Akihiro Morita, Shen Ye

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

To develop an efficient material for the cathode of the lithium-oxygen (Li-O 2 ) secondary battery, the oxygen reduction and evolution reactions (ORR and OER) on a well-defined graphene electrode have been investigated in a typical organic solvent, dimethyl sulfoxide (DMSO). The adsorption and desorption behaviors of the solvents on the graphene electrode surface were evaluated by an intrinsically surface-selective vibrational spectroscopy of sum frequency generation (SFG) during the ORR and OER. After the initial ORR depositing lithium peroxide (Li 2 O 2 ) on the graphene electrode surface in a LiClO 4 /DMSO solution, the SFG spectroscopy revealed that the subsequent OER oxidizing the Li 2 O 2 preferentially proceeds at the interface between the Li 2 O 2 and graphene rather than that between the Li 2 O 2 and bulk solution. Therefore, the OER tends to reduce the electric conductivity between the Li 2 O 2 and graphene by decreasing their contact area before a large part of the deposited Li 2 O 2 was oxidized, which elucidates the origin of the high overpotential for the OER.

Original languageEnglish
Pages (from-to)15568-15571
Number of pages4
JournalJournal of the American Chemical Society
Volume140
Issue number46
DOIs
Publication statusPublished - 2018 Nov 21

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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