Effect of dopant nature on structures and lattice dynamics of proton-conducting BaZrO3

Sahraoui, D. Zeudmi; Mineva, Tzonka

doi:10.1016/j.ssi.2013.10.002

Cited by 18 publications

(9 citation statements)

References 48 publications

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“…The radius of the circle, r , as obtained from the fits in Figure , represents, in the case of jump diffusion over two sites (proton transfers), half of the jump length and, in the case of jump diffusion over four sites (O–H rotation), the O–H distance. The obtained jump lengths, 1.4 to 1.6 Å for proton transfers and 0.85 to 1.0 Å for O–H rotational motions (Table S1 in SI), are in good agreement with both crystallographic data and calculations of O–O distances (∼2.6 to 2.9 Å) and calculated O–H bond lengths (0.97 to 1.00 Å) ,,,, as well as with jump distances obtained in other QENS studies of the same and similar materials such as SrCe 0.95 Yb 0.05 H 0.02 O 2.985 and Ba[Ca (1+ x )/3 Nb (2– x )/3 ]O 3– x /2 . , Previous work, carried out at higher resolution (∼100 μeV) but over a smaller Q range (∼0.2 to 2.0 Å –1 ), suggested the possibility to distinguish between transfer and O–H rotational diffusion in the Q range probed by the present study. It is shown here, however, that a set of physically reasonable parameters allows a good description of the experimental data according to both models.…”

Section: Results and Discussionsupporting

confidence: 88%

Localized Proton Motions in Acceptor-Doped Barium Zirconates

2017

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Acceptor-doped barium zirconates are currently accumulating considerable interest because of their high proton conductivity, especially in the intermediatetemperature range targeted for next-generation solid oxide fuel cells, combined with their excellent chemical stability. However, fundamental questions surrounding the proton conduction mechanism in these materials remain, for instance, regarding the nature of localized proton motions and how they depend on the local structural properties of the material. Here we investigate the nature of localized proton motions in the two acceptordoped proton-conducting perovskites BaZr 0.9 M 0.1 O 2.95 with M = Y and Sc, using quasielastic neutron scattering. We show the presence of pronounced localized proton dynamics, with mean residence periods on the time-scale of 1−30 ps and an activation energy of ∼100 meV for both materials. In view of first-principles calculations as reported elsewhere the experimentally established dynamics could comprise footprints from proton transfers as well as O−H rotational motions in several different types of proton sites due to a range of various local proton sites present in both materials.

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Section: Results and Discussionsupporting

confidence: 88%

Localized Proton Motions in Acceptor-Doped Barium Zirconates

2017

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“…(a) Pressure-dependent Raman spectra for BaZr 0.9 Y 0.1 O 3‑δ : (i) Ba–ZrO 6 stretching, (ii) ZrO 6 torsional motion, (iii) O–Zr–O bending motion, and (iv) Zr–O stretching motion . (b) Change in phonon frequencies as a function of pressure.…”

Section: Resultsmentioning

confidence: 70%

“…At 2.5 GPa, two Raman bands at 117 and 381 cm –1 appear and become prominent with an increase in the pressure. According to the density functional theory simulation, the vibration modes at the wavenumber range of 60–139 cm –1 represent the Ba–ZrO 6 stretching motion, 169–233 cm –1 correspond to the ZrO 6 torsional motion, 270–450 cm –1 assigned to the O–Zr–O bending motion, and 456–821 cm –1 attributed to the Zr–O stretching motion. Therefore, the Raman bands at 107 and 117 cm –1 are assigned to the Ba–ZrO 6 stretching motion.…”

Section: Resultsmentioning

confidence: 99%

Influence of Lattice Dynamics on the Proton Transport in BaZrY-Oxide Perovskites under High Pressure

Fan

et al. 2020

J. Phys. Chem. C

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Proton-conducting metal oxides such as Y-doped BaZrO3 have a wide application prospect as electrochemical energy converters at intermediate temperature. Understanding their proton transport mechanisms is important for improving the proton conductivity. Here, we investigate the influence of the crystal structure and the lattice dynamics of the BaZr0.9Y0.1O3‑δ proton conductor using high-pressure Raman spectroscopy and high-pressure X-ray diffraction. A linear increase in the Raman shifts with pressure between 2.7 and 7.5 cm–1GPa–1 is observed for the vibrational modes higher than 450 cm–1 but almost invariant for vibrational modes less than 450 cm–1, highlighting the more significant phonon hardening effect of Zr–O stretching motions at high pressure than other motions. When the pressure increases from ambient pressure to 2 GPa, despite the 4 orders of magnitude enhancement in the Arrhenius prefactor and attempt frequency, the 2-fold increase in the activation energy results in a smaller proton conductivity at low temperature upon phonon hardening. A scenario of proton transfer combined with the Zr–O stretching motion to overcome the energy barrier is illustrated. According to the proton polaron model, the calculated polaron radius lies in the range of lattice parameters, suggesting the formation of lattice polarons in BaZr0.9Y0.1O3‑δ. Our findings suggest that a softer lattice can enhance the low-temperature proton conductivity with a reduced energy barrier.

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“…It can be found, for the samples modified by In, the conductivity decreased significantly with increasing In concentration, although the relatively density of the samples increased accordingly. As was reported, the formation and especially mobility of proton defects are very sensitive to the dopants for BaZrO 3 ‐based oxides . In‐doped BaZrO 3 exhibits poorer hydration behavior and lower proton mobility than Y‐doped BaZrO 3 , which eventually results in lower bulk conductivity of In‐doped BaZrO 3 .…”

Section: Resultsmentioning

confidence: 75%

“…As was reported, the formation and especially mobility of proton defects are very sensitive to the dopants for BaZrO 3 ‐based oxides . In‐doped BaZrO 3 exhibits poorer hydration behavior and lower proton mobility than Y‐doped BaZrO 3 , which eventually results in lower bulk conductivity of In‐doped BaZrO 3 . Moreover, as can be seen in Figure , the apparent activation energy (E a ) values for proton conductivity increased correspondingly with In concentration, further suggesting that protons are more easily trapped and hence more difficult to hop in crystal lattice after In‐doping.…”

Section: Resultsmentioning

confidence: 75%

An Easily Sintered, Chemically Stable, Barium Zirconate‐Based Proton Conductor for High‐Performance Proton‐Conducting Solid Oxide Fuel Cells

Sun

Shi

Liu

et al. 2014

Adv Funct Materials

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Yttrium and indium co‐doped barium zirconate is investigated to develop a chemically stable and sintering active proton conductor for solid oxide fuel cells (SOFCs). BaZr0.8Y0.2‐xInxO3‐ δ possesses a pure cubic perovskite structure. The sintering activity of BaZr0.8Y0.2‐xInxO3‐ δ increases significantly with In concentration. BaZr0.8Y0.15In0.05O3‐ δ (BZYI5) exhibits the highest total electrical conductivity among the sintered oxides. BZYI5 also retains high chemical stability against CO2, vapor, and reduction of H2. The good sintering activity, high conductivity, and chemical stability of BZYI5 facilitate the fabrication of durable SOFCs based on a highly conductive BZYI5 electrolyte film by cost‐effective ceramic processes. Fully dense BZYI5 electrolyte film is successfully prepared on the anode substrate by a facile drop‐coating technique followed by co‐firing at 1400 °C for 5 h in air. The BZYI5 film exhibits one of the highest conductivity among the BaZrO3‐based electrolyte films with various sintering aids. BZYI5‐based single cells output very encouraging and by far the highest peak power density for BaZrO3‐based proton‐conducting SOFCs, reaching as high as 379 mW cm−2 at 700 °C. The results demonstrate that Y and In co‐doping is an effective strategy for exploring sintering active and chemically stable BaZrO3‐based proton conductors for high performance proton‐conducting SOFCs.

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Effect of dopant nature on structures and lattice dynamics of proton-conducting BaZrO3

Cited by 18 publications

References 48 publications

Localized Proton Motions in Acceptor-Doped Barium Zirconates

Localized Proton Motions in Acceptor-Doped Barium Zirconates

Influence of Lattice Dynamics on the Proton Transport in BaZrY-Oxide Perovskites under High Pressure

An Easily Sintered, Chemically Stable, Barium Zirconate‐Based Proton Conductor for High‐Performance Proton‐Conducting Solid Oxide Fuel Cells

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