Operando observations of RuO2 catalyzed Li2O2 formation and decomposition in a Li-O2 micro-battery

Chen Hou, Jiuhui Han, Pan Liu*, Chuchu Yang, Gang Huang, Takeshi Fujita, Akihiko Hirata, Mingwei Chen

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

43 Citations (Scopus)


RuO2 displays excellent bifunctional catalysis towards the oxygen reduction and evolution reactions of Li-O2 battery. Nevertheless, how the solid catalyst successively catalyzes solid Li2O2 formation and decomposition, confronting passivation and loss of RuO2/Li2O2 contact, during discharging and charging remains a mystery. Here we report operando observations of RuO2 catalyzed oxygen reduction and evolution reactions of Li2O2 by utilizing a liquid cell scanning transmission electron microscope. Upon discharging, RuO2 obviously accelerates formation of soluble LiO2 intermediates and acts as preferential sites of Li2O2 precipitation. During charging, the catalytic activation of RuO2 takes place at electrolyte-RuO2-Li2O2 triple-phase interfaces. Importantly, RuO2 not only catalyzes the decomposition of directly contacted Li2O2, but also promotes oxidation of soluble LiO2 for rapid dissolution of isolated Li2O2 nanoparticles by a chemical comproportionation reaction. The observation unveils how RuO2 catalyzes the formation and decomposition of Li2O2 during discharging and charging and provides nanoscale insights into cathodic reactions of Li-O2 batteries with solid catalysts.

Original languageEnglish
Pages (from-to)427-433
Number of pages7
JournalNano Energy
Publication statusPublished - 2018 May
Externally publishedYes


  • Liquid cell electron microscopy
  • Lithium-oxygen battery
  • RuO catalyst
  • Scanning transmission electron microscopy

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • General Materials Science
  • Electrical and Electronic Engineering


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