MRS Communications

Research Letters

Ab initio evaluation of oxygen diffusivity in LaFeO3: the role of lanthanum vacancies

Andrew M. Ritzmanna1, Ana B. Muñoz-Garcíaa2, Michele Pavonea2, John A. Keitha3 and Emily A. Cartera4 c1

a1 Department of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544

a2 Department of Chemical Sciences, University of Naples Federico II, Naples 80126, Italy

a3 Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544

a4 Department of Mechanical and Aerospace Engineering, Program in Applied and Computational Mathematics, and Andlinger Center for Energy and Environment, Princeton University, Princeton, New Jersey 08544

Abstract

Solid oxide fuel cells (SOFCs) are attractive for clean and efficient electricity generation, but high operating temperatures (T op > 800 °C) limit their widespread usage. Oxygen ion conducting cathode materials (mixed ion-electron conductors, MIECs), such as La1−x Sr x Co1−y Fe y O3 (LSCF), enable lower T op by reducing cathode polarization losses. Understanding how composition affects oxygen diffusion in LaFeO3 is vitally important for designing high-performance LSCF cathodes. To do this, we employ first-principles density functional theory plus U (DFT+U) calculations to show how lanthanum vacancies in LaFeO3 dramatically change the oxygen diffusion coefficient. Our ab initio results show that A-site substoichiometry is a viable route to increased oxygen diffusion and higher SOFC performance.

(Received May 09 2013)

(Accepted July 29 2013)

Correspondence

c1 Address all correspondence to Emily A. Carter at eac@princeton.edu

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