Diffusional Dynamics of Hydride Ions in the Layered Oxyhydride SrVO2H
Journal article, 2021

Perovskite-type oxyhydrides are hydride-ion-conducting materials of promise for several types of technological applications; however, the conductivity is often too low for practical use and, on a fundamental level, the mechanism of hydride-ion diffusion remains unclear. Here, we, with the use of neutron scattering techniques, investigate the diffusional dynamics of hydride ions in the layered perovskite-type oxyhydride SrVO2H. By monitoring the intensity of the elastically scattered neutrons upon heating the sample from 100 to 430 K, we establish an onset temperature for diffusional hydride-ion dynamics at about 250 K. Above this temperature, the hydride ions are shown to exhibit two-dimensional diffusion restricted to the hydride-ion sublattice of SrVO2H and that occurs as a series of jumps of a hydride ion to a neighboring hydride-ion vacancy, with an enhanced rate for backward jumps due to correlation effects. Analysis of the temperature dependence of the neutron scattering data shows that the localized jumps of hydride ions are featured by a mean residence time of the order of 10 ps with an activation energy of 0.1 eV. The long-range diffusion of hydride ions occurs on the timescale of 1 ns and with an activation energy of 0.2 eV. The hydride-ion diffusion coefficient is found to be of the order of 1 × 10-6 cm2 s-1 in the temperature range of 300-430 K, which is similar to other oxyhydrides but higher than for proton-conducting perovskite analogues. Tuning of the hydride-ion vacancy concentration in SrVO2H thus represents a promising gateway to improve the ionic conductivity of this already highly hydride-ion-conducting material.

Author

Rasmus Lavén

Chalmers, Chemistry and Chemical Engineering, Energy and Material, Environmental Inorganic Chemistry 2

Ulrich Häussermann

Stockholm University

Adrien Perrichon

STFC Rutherford Appleton Laboratory

Mikael Andersson

Chalmers, Chemistry and Chemical Engineering, Energy and Material, Environmental Inorganic Chemistry 2

Michael Sannemo Targama

Stockholm University

F. Demmel

STFC Rutherford Appleton Laboratory

Maths Karlsson

Chalmers, Chemistry and Chemical Engineering, Energy and Material, Environmental Inorganic Chemistry 2

Chemistry of Materials

0897-4756 (ISSN) 1520-5002 (eISSN)

Vol. 38 8 2967-2975

Surface/interface dynamics investigated with neutron scattering

Swedish Research Council (VR) (2016-06958), 2017-01-01 -- 2020-12-31.

Subject Categories

Materials Chemistry

Fusion, Plasma and Space Physics

Condensed Matter Physics

DOI

10.1021/acs.chemmater.1c00505

PubMed

34054217

More information

Latest update

5/20/2021