Nanoscale probing of voltage activated oxygen reduction/evolution reactions in nanopatterned (LaxSr1-x)CoO3-δ cathodes

Donovan N. Leonard, Amit Kumar, Stephen Jesse, Michael D. Biegalski, Hans M. Christen, Eva Mutoro, Ethan J. Crumlin, Yang Shao-Horn, Sergei V. Kalinin, Albina Y. Borisevich

Research output: Contribution to journalArticlepeer-review

22 Scopus citations

Abstract

Bias-dependent mechanisms of reversible and irreversible electrochemical processes on a (La0.5Sr0.5)2CoO 4±δ modified (LaxSr1-x)CoO 3- surface are studied using dynamic electrochemical strain microscopy (D-ESM). The reversible oxygen reduction/evolution process is activated at voltages as low as 3-4 V and the degree of transformation increases linearly with applied bias. The irreversible processes associated with static surface deformation become apparent above 10-12 V. Post-mortem focused-ion milling combined with atomic resolution scanning transmission electron microscopy and electron energy loss spectroscopy is used to establish the mechanisms of irreversible transformations and attribute it to amorphization of the top layer of material. These studies both establish the framework for probing irreversible electrochemical processes in solids and illustrate rich spectrum of electrochemical transformations underpinning electrocatalytic activity in cobaltites.

Original languageEnglish
Pages (from-to)788-797
Number of pages10
JournalAdvanced Energy Materials
Volume3
Issue number6
DOIs
StatePublished - Jun 2013

Keywords

  • cobaltites
  • electrochemical strain microscopy
  • oxygen vacancy ordering
  • scanning transmission electron microscopy
  • solid oxide fuel cells

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