Details
| Original language | English |
|---|---|
| Article number | 115067 |
| Journal | Solid State Ionics |
| Volume | 343 |
| Early online date | 30 Oct 2019 |
| Publication status | Published - 15 Dec 2019 |
| Externally published | Yes |
Abstract
Ionic conductors based on PbF2, being one of the archetypes to study ion dynamics, serve as excellent model substances to study the elementary steps of translational anion dynamics in the solid state. Here, high-energy ball milling was employed to prepare a structurally disordered, metastable solid solution by mixing PbF2 with CaF2. The cation-mixed lattice in cubic Ca0.4Pb0.6F2 provides a range of magnetically distinct fluorine sites. We used 2D 19F magic angle spinning nuclear magnetic resonance (NMR) exchange spectroscopy to reveal the site preference of the F anions when hopping through the lattice. It turned out that the F anions located in sites coordinated by Pb cations are more mobile than those residing near or in Ca-rich environments. Conductivity measurements and variable-temperature 19F NMR spin-lattice relaxation experiments provide activation energies (0.24 eV, 0.40 eV) from which we deduce that in cation-mixed Ca0.4Pb0.6F2 anion diffusivity, on the angstrom length-scale, is mainly determined by vacant F− sites. Macroscopic ion transport has to be characterized by an activation energy of 0.55 eV suggesting that the F anions also use interstitial sites for long-range ionic transport.
ASJC Scopus subject areas
- Chemistry(all)
- General Chemistry
- Materials Science(all)
- General Materials Science
- Physics and Astronomy(all)
- Condensed Matter Physics
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In: Solid State Ionics, Vol. 343, 115067, 15.12.2019.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Self-diffusion and ionic exchange in mechanosynthesized, nanocrystalline solid solutions of PbF2 and CaF2 –19F 2D NMR visualizes the flourine hopping preferences
AU - Lunghammer, S.
AU - Düvel, Andre
AU - Posch, P.
AU - Kunert, B.
AU - Resel, R.
AU - Wilkening, H. M. R.
N1 - Funding information: Financial support by the Deutsche Forschungsgemeinschaft (DFG) SPP priority programme 1415 is highly appreciated. Furthermore, we thank the DFG for financial support in the frame of the DFG research unit ‘molife’ 1277.
PY - 2019/12/15
Y1 - 2019/12/15
N2 - Ionic conductors based on PbF2, being one of the archetypes to study ion dynamics, serve as excellent model substances to study the elementary steps of translational anion dynamics in the solid state. Here, high-energy ball milling was employed to prepare a structurally disordered, metastable solid solution by mixing PbF2 with CaF2. The cation-mixed lattice in cubic Ca0.4Pb0.6F2 provides a range of magnetically distinct fluorine sites. We used 2D 19F magic angle spinning nuclear magnetic resonance (NMR) exchange spectroscopy to reveal the site preference of the F anions when hopping through the lattice. It turned out that the F anions located in sites coordinated by Pb cations are more mobile than those residing near or in Ca-rich environments. Conductivity measurements and variable-temperature 19F NMR spin-lattice relaxation experiments provide activation energies (0.24 eV, 0.40 eV) from which we deduce that in cation-mixed Ca0.4Pb0.6F2 anion diffusivity, on the angstrom length-scale, is mainly determined by vacant F− sites. Macroscopic ion transport has to be characterized by an activation energy of 0.55 eV suggesting that the F anions also use interstitial sites for long-range ionic transport.
AB - Ionic conductors based on PbF2, being one of the archetypes to study ion dynamics, serve as excellent model substances to study the elementary steps of translational anion dynamics in the solid state. Here, high-energy ball milling was employed to prepare a structurally disordered, metastable solid solution by mixing PbF2 with CaF2. The cation-mixed lattice in cubic Ca0.4Pb0.6F2 provides a range of magnetically distinct fluorine sites. We used 2D 19F magic angle spinning nuclear magnetic resonance (NMR) exchange spectroscopy to reveal the site preference of the F anions when hopping through the lattice. It turned out that the F anions located in sites coordinated by Pb cations are more mobile than those residing near or in Ca-rich environments. Conductivity measurements and variable-temperature 19F NMR spin-lattice relaxation experiments provide activation energies (0.24 eV, 0.40 eV) from which we deduce that in cation-mixed Ca0.4Pb0.6F2 anion diffusivity, on the angstrom length-scale, is mainly determined by vacant F− sites. Macroscopic ion transport has to be characterized by an activation energy of 0.55 eV suggesting that the F anions also use interstitial sites for long-range ionic transport.
UR - http://www.scopus.com/inward/record.url?scp=85074145235&partnerID=8YFLogxK
U2 - 10.1016/j.ssi.2019.115067
DO - 10.1016/j.ssi.2019.115067
M3 - Article
AN - SCOPUS:85074145235
VL - 343
JO - Solid State Ionics
JF - Solid State Ionics
SN - 0167-2738
M1 - 115067
ER -