Probing Bias-Dependent Electrochemical Gas-Solid Reactions in (LaxSr1-x)CoO3-delta Cathode Materials

Amit Kumar*, Francesco Ciucci, Donovan Leonard, Stephen Jesse, Mike Biegalski, Hans Christen, Eva Mutoro, Ethan Crumlin, Yang Shao-Horn, Albina Borisevich, Sergei V. Kalinin

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)

Abstract

Spatial variability of bias-dependent electrochemical processes on a (La0.5Sr0.5)(2)CoO4 +/- modified (LaxSr1-x)CoO3- surface is studied using first-order reversal curve method in electrochemical strain microscopy (ESM). The oxygen reduction/evolution reaction (ORR/OER) is activated at voltages as low as 3-4 V with respect to bottom electrode. The degree of bias-induced transformation as quantified by ESM hysteresis loop area increases with applied bias. The variability of electrochemical activity is explored using correlation analysis and the ORR/OER is shown to be activated in grains at relatively low biases, but the final reaction rate is relatively small. At the same time, at grain boundaries, the onset of reaction process corresponds to larger voltages, but limiting reactivity is much higher. The reaction mechanism in ESM of mixed electronic-ionic conductor is further analyzed. These studies both establish the framework for probing bias-dependent electrochemical processes in solids and demonstrate rich spectrum of electrochemical transformations underpinning catalytic activity in cobaltites.

Original languageEnglish
Pages (from-to)5027-5036
Number of pages10
JournalAdvanced Functional Materials
Volume23
Issue number40
DOIs
Publication statusPublished - Oct 2013

Keywords

  • fuel cell
  • cathodes
  • electrochemical strain
  • scanning probe microscopy
  • OXIDE FUEL-CELLS
  • OXYGEN-REDUCTION KINETICS
  • RESISTIVE SWITCHING MEMORIES
  • ELECTRONIC BAND-STRUCTURE
  • PEROVSKITE THIN-FILMS
  • REDUCTION/EVOLUTION REACTIONS
  • COULOMETRIC TITRATION
  • NANOMETER RESOLUTION
  • ION DIFFUSION
  • SURFACE

ASJC Scopus subject areas

  • Biomaterials
  • Electrochemistry
  • Condensed Matter Physics
  • Electronic, Optical and Magnetic Materials

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