Positive role of oxygen vacancy in electrochemical performance of CoMn2O4 cathodes for Li-O2 batteries

Zoya Sadighi, Jiaqiang Huang, Lei Qin, Shanshan Yao, Jiang Cui, Jang Kyo Kim

Research output: Contribution to journalArticlepeer-review

83 Scopus citations

Abstract

The thermally induced oxygen vacancies present across the intra/inter-crystalline sites and surface of ultrafine CoMn2O4 (CMO) electrodes ameliorate electrochemical performance of Li-O2 batteries (LOBs). Oxygen deficient CMOs are synthesized via a two-step process: in situ reduction to achieve a large surface area of 151.3 m2 g−1 and thermal treatment at 400 °C in pure Ar. The oxygen deficient CMO electrode presents a higher initial capacity, lower overpotential, better cyclic stability, higher Coulombic efficiencies and higher rate capabilities than the as-prepared CMO electrode without heat treatment. While the CMO electrode presents an excellent catalytic behavior in oxygen reduction reaction (ORR), the oxygen vacancies mitigate the migration of Li+ ions and electrons and act as active sites for O2 in the oxygen evolution reaction (OER). The ex situ characterization also proves a lower kinetic charge transfer resistance and higher catalytic activities of the oxygen deficient CMO electrodes in the decomposition of discharge products during the discharge/charge cycles.

Original languageBritish English
Pages (from-to)134-147
Number of pages14
JournalJournal of Power Sources
Volume365
DOIs
StatePublished - 15 Oct 2017

Keywords

  • Ar heat treatment
  • CoMnO
  • In situ reduction
  • Li-O batteries
  • Oxygen vacancy

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