Abstract
Proton-conducting perovskites have been widely studied because of their potential application as solid electrolytes in intermediate temperature solid oxide fuel cells. Structural and chemical heterogeneities can develop during synthesis, device fabrication, or service, which can profoundly affect proton transport. Here, we use time-resolved Kelvin probe force microscopy, scanning transmission electron microscopy, atom probe tomography, and density functional theory calculations to intentionally introduce Ba-deficient planar and spherical defects and link the resultant atomic structure with proton transport behavior in both stoichiometric and nonstoichiometric epitaxial, yttrium-doped barium zirconate thin films. The defects were intentionally induced through high-temperature annealing treatment, while maintaining the epitaxial single crystalline structure of the films, with an overall relaxation in the atomic structure. The annealed samples showed smaller magnitudes of local lattice distortions because of the formation of proton polarons, thereby leading to decreased proton-trapping effect. This resulted in a decrease in the activation energy for proton transport, leading to faster proton transport.
| Original language | English |
|---|---|
| Pages (from-to) | 4816-4823 |
| Number of pages | 8 |
| Journal | ACS Applied Materials and Interfaces |
| Volume | 10 |
| Issue number | 5 |
| DOIs | |
| State | Published - Feb 7 2018 |
Funding
This research was sponsored by the Laboratory Directed Research and Development Program (LDRD) of Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for the U.S. Department of Energy. Part of this research used resources of the National Energy Research Scientific Computing Center, which is supported by the Office of Science of the U.S. Department of Energy under contract no. DE-AC02-05CH11231. Part of this research used resources of the Oak Ridge Leadership Computing Facility at the Oak Ridge National Laboratory, which is supported by the Office of Science of the U.S. Department of Energy under contract no. DE-AC05-00OR22725. Materials synthesis, device fabrication, and characterization (PLD, STEM, tr-KPFM, and APT) were conducted at the Center for Nanophase Materials Sciences, which is a U.S. Department of Energy Office of Science User Facility. J.D. and N.B.-G. gratefully acknowledge support from the U.S. National Science Foundation through grant DMR-1255379.
Keywords
- Kelvin probe force microscopy
- atom probe tomography
- density functional theory
- proton-conducting solid oxide fuel cells
- scanning transmission electron microscopy
- yttrium-doped barium zirconate
