1. Study of Defect Chemistry in the System La2–xSrxNiO4+δ by 17O Solid-State NMR Spectroscopy and Ni K-Edge XANES
- Author
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Matthew T. Dunstan, Sylvia Britto, Clare P. Grey, David M. Halat, and Michael W. Gaultois
- Subjects
Fermi contact interaction ,Chemistry ,General Chemical Engineering ,Analytical chemistry ,Ionic bonding ,02 engineering and technology ,General Chemistry ,Nuclear magnetic resonance spectroscopy ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,XANES ,0104 chemical sciences ,Solid-state nuclear magnetic resonance ,Materials Chemistry ,Ionic conductivity ,0210 nano-technology ,Spectroscopy ,Hyperfine structure - Abstract
The properties of mixed ionic–electronic conductors (MIECs) are most conveniently controlled through site-specific aliovalent substitution, yet few techniques can report directly on the local structure and defect chemistry underpinning changes in ionic and electronic conductivity. In this work, we perform high-resolution 17O (I = 5/2) solid-state NMR spectroscopy of La2–xSrxNiO4+δ, an MIEC and prospective solid oxide fuel cell (SOFC) cathode material, showing the sensitivity of 17O hyperfine (Fermi contact) shifts and quadrupolar coupling constants due to local structural changes arising from Sr substitution (x). Previously, we resolved resonances from three distinct oxygen sites (interstitial, axial, and equatorial) in the unsubstituted x = 0 material (Halat et al., J. Am. Chem. Soc. 2016, 138, 11958). Here, substitution-induced changes in these three spectral features indirectly report on the ionic conductivity, local octahedral tilting, and electronic conductivity, respectively, of the (substituted) ma...
- Published
- 2018