title: Probing Grain-Boundary Chemistry and Electronic Structure in Proton-Conducting Oxides by Atom Probe Tomography.
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 (BaZr0.9Y0.1O3-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.
authors.affiliation: Renewable Energy Materials Research Science and Engineering Center (REMRSEC), Colorado School of Mines , 1500 Illinois St., Golden, Colorado 80401, United States.|Center for Advanced Ceramics, Metallurgical and Materials Engineering, Colorado School of Mines , Golden, Colorado 80401, United States.
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Clark
authors.affiliation: Department of Mechanical Engineering, Colorado School of Mines , 1500 Illinois St., Golden, Colorado 80401, United States.
authors.forename: Huayang
authors.initials: H
authors.lastname: Zhu
authors.affiliation: Center for Advanced Ceramics, Metallurgical and Materials Engineering, Colorado School of Mines , Golden, Colorado 80401, United States.
authors.forename: David R
authors.initials: DR
authors.lastname: Diercks
authors.affiliation: Department of Mechanical Engineering, Colorado School of Mines , 1500 Illinois St., Golden, Colorado 80401, United States.
authors.forename: Sandrine
authors.initials: S
authors.lastname: Ricote
authors.affiliation: Department of Mechanical Engineering, Colorado School of Mines , 1500 Illinois St., Golden, Colorado 80401, United States.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Kee
authors.affiliation: Department of Chemical Engineering, The Petroleum Institute , Post Office Box 2533, Abu Dhabi, United Arab Emirates.
authors.forename: Ali
authors.initials: A
authors.lastname: Almansoori
authors.affiliation: Center for Advanced Ceramics, Metallurgical and Materials Engineering, Colorado School of Mines , Golden, Colorado 80401, United States.
authors.forename: Brian P
authors.initials: BP
authors.lastname: Gorman
authors.affiliation: Renewable Energy Materials Research Science and Engineering Center (REMRSEC), Colorado School of Mines , 1500 Illinois St., Golden, Colorado 80401, United States.|Center for Advanced Ceramics, Metallurgical and Materials Engineering, Colorado School of Mines , Golden, Colorado 80401, United States.
authors.forename: Ryan P
authors.initials: RP
authors.lastname: O'Hayre
keywords: Atom probe tomography; grain boundary characterization; proton-conducting ceramics; space-charge layer