Probing Grain-Boundary Chemistry and Electronic Structure in Proton-Conducting Oxides by Atom Probe Tomography

Daniel R Clark; Huayang Zhu; David R Diercks; Sandrine Ricote; Robert J Kee; Ali Almansoori; Brian P Gorman; Ryan P O'Hayre

doi:10.1021/acs.nanolett.6b02918

Probing Grain-Boundary Chemistry and Electronic Structure in Proton-Conducting Oxides by Atom Probe Tomography

Nano Lett. 2016 Nov 9;16(11):6924-6930. doi: 10.1021/acs.nanolett.6b02918. Epub 2016 Oct 5.

Authors

Daniel R Clark^{1

2}, Huayang Zhu³, David R Diercks², Sandrine Ricote³, Robert J Kee³, Ali Almansoori⁴, Brian P Gorman², Ryan P O'Hayre^{1

2}

Affiliations

¹ Renewable Energy Materials Research Science and Engineering Center (REMRSEC), Colorado School of Mines , 1500 Illinois St., Golden, Colorado 80401, United States.
² Center for Advanced Ceramics, Metallurgical and Materials Engineering, Colorado School of Mines , Golden, Colorado 80401, United States.
³ Department of Mechanical Engineering, Colorado School of Mines , 1500 Illinois St., Golden, Colorado 80401, United States.
⁴ Department of Chemical Engineering, The Petroleum Institute , Post Office Box 2533, Abu Dhabi, United Arab Emirates.

PMID: 27696864
DOI: 10.1021/acs.nanolett.6b02918

Abstract

A laser-assisted atom-probe-tomographic (LAAPT) method has been developed and applied to measure and characterize the three-dimensional atomic and electronic nanostructure at an yttrium-doped barium zirconate (BaZr_0.9Y_0.1O_3-δ, BZY10) grain boundary. Proton-conducting perovskites, such as BZY10, are attracting intense interest for a variety of energy conversion applications. However, their implementation has been hindered, in part, because of high grain-boundary (GB) resistance that is attributed to a positive GB space-charge layer (SCL). In this study, LAAPT is used to analyze BZY10 GB chemistry in three dimensions with subnanometer resolution. From this analysis, maps of the charge density and electrostatic potential arising at the GBs are derived, revealing for the first time direct chemical evidence that a positive SCL indeed exists at these GBs. These maps reveal new insights on the inhomogeneity of the SCL region and produce an average GB potential barrier of approximately 580 mV, agreeing with previous indirect electrochemical measurements.

Keywords: Atom probe tomography; grain boundary characterization; proton-conducting ceramics; space-charge layer.

Publication types

Research Support, U.S. Gov't, Non-P.H.S.