Adaptive kinetic Monte Carlo simulation of solid oxide fuel cell components

David S D Gunn*, Neil L. Allan, John A. Purton

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)

11 Citations (Scopus)

Abstract

Ionic conductivities in the solid oxide fuel cell (SOFC) electrolytes yttria-stabilised zirconia (YSZ), calcia-stabilised zirconia (CSZ), gadolinium-doped ceria (GDC) and samarium-doped ceria (SDC) and the cathode material lanthanum strontium cobalt oxide (LSCO) are directly calculated using DL-AKMC, an adaptive kinetic Monte Carlo (aKMC) program which assumes limited a priori knowledge of the kinetics of systems. The materials were simulated over several milliseconds and over the range of experimentally most relevant temperatures and dopant concentrations (2-18 mol% for doped zirconia, 5-25 mol% for doped ceria and 5-80 mol% for LSCO). Ionic conductivities of the electrolytes at 1000 K are in good agreement with the observed values: CSZ in the range 3 × 10-3 to 1 × 10-2 S cm -1 depending on dopant concentration, YSZ 4 × 10-3 to 3 × 10-2 S cm-1, GDC 1 × 10-2 to 5 × 10-2 S cm-1, SDC 1 × 10-2 to 7 × 10-2 S cm-1. LSCO is predicted to have an ionic conductivity of the order of 10-2 to 10-1 S cm -1 depending on Sr content. Average activation energies over all migration processes are 0.4-0.5 eV for the stabilised zirconias and 0.2-0.3 eV for the doped cerias and 0.3 eV for LSCO, in agreement with experiment. aKMC provides a distinct advantage over traditional KMC methods, in which one has to provide a list of system state transitions. Here, all of the state transitions are dynamically generated, leading to a more accurate simulation of the kinetics as the system evolves. This journal is © the Partner Organisations 2014.

Original languageEnglish
Pages (from-to)13407-13414
Number of pages8
JournalJournal of Materials Chemistry A
Volume2
Issue number33
DOIs
Publication statusPublished - 7 Sep 2014

Keywords

  • YTTRIA-STABILIZED ZIRCONIA
  • MOLECULAR-DYNAMICS
  • IONIC-CONDUCTIVITY
  • SURFACE-DIFFUSION
  • OXYGEN-TRANSPORT
  • LANTHANUM COBALTITES
  • TRANSITION-STATES
  • SADDLE-POINTS
  • SOFC CATHODE
  • CERIA

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