Structural study and proton conductivity in Yb-doped BaZrO3

Ahmed, Istaq; Eriksson, Sten; Ahlberg, Elisabet; Knee, Christopher S.; Götlind, Helena; Johansson, Lars‐Gunnar; Karlsson, Mattias; Matic, Aleksandar; Börjesson, Lars

doi:10.1016/j.ssi.2006.11.011

Cited by 60 publications

(39 citation statements)

References 24 publications

(31 reference statements)

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“…1, the grain boundary resistance is not the dominant factor in determining the proton conductivity of either of these Ti based pyrochlore systems. This behaviour contrasts with results consistently obtained for proton conducting BaZrO 3 perovskites [21,22] where high grain boundary impedance severely limits the total conductivity. Our findings may also be compared with the work of Fjeld et al [14] on Er 1.96 Ca 0.04 Ti 2 O 6.98 who report the absence of bulk proton conduction, but rather conclude that proton transport occurs mainly at the grain boundary.…”

Section: Discussioncontrasting

confidence: 99%

“…It was proposed that the 3517 cm − 1 peak reflected the presence of protons bound to the O(2), 8b, oxygen ion, whereas the lower frequency bands were The presence of distinct, and relatively sharp, IR-bands appears to be a feature of hydrated pyrochlores and is reminiscent of spectra recorded for hydroxides, in which the OH-groups reside in specific crystallographic positions. This behaviour differs from the spectra typically observed for acceptor doped perovskites where much broader IR bands with widths of ∼ 200-500 cm − 1 are generally observed [21][22][23]. In addition, the O-H stretch region of perovskites is generally found at lower frequencies.…”

Section: Discussioncontrasting

confidence: 77%

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Investigation of proton conductivity in Sm1.92Ca0.08Ti2O7−δ and Sm2Ti1.92Y0.08O7−δ pyrochlores

et al. 2010

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Section: Discussioncontrasting

confidence: 99%

Section: Discussioncontrasting

confidence: 77%

Investigation of proton conductivity in Sm1.92Ca0.08Ti2O7−δ and Sm2Ti1.92Y0.08O7−δ pyrochlores

et al. 2010

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“…Analogous behavior has been reported previously for many systems. 14,15,[28][29][30] Given the difference between pelletized and powder samples, we do not attempt to quantitatively compare the TGA and conductivity data because the level of protonation may differ slightly. Nonetheless, it seems a safe assumption that the level of hydration determined from the TGA represents the value close to the maximum possible water content present in the prehydrated conductivity pellet.…”

Section: P100mentioning

confidence: 99%

Proton Conduction in Perovskite Oxide BaZr[sub 0.5]Yb[sub 0.5]O[sub 3−δ] Prepared by Wet Chemical Synthesis Route

Ahmed

Knee

Eriksson

et al. 2008

J. Electrochem. Soc.

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A wet chemical route has been used to synthesize the oxygen deficient perovskite BaZr 0.5 Yb 0.5 O 3−␦ . Analysis of X-ray powder diffraction data showed that both dried and hydrated samples adopt cubic crystal structures of space group Pm3m. Dynamic thermogravimetric analysis showed a significant mass loss for the hydrated sample compared to the dried sample, indicating that ϳ28% of the oxygen vacancies are filled by protonic defects. The strong O-H stretch band, 2500-3500 cm −1 , in the IR absorbance spectrum also clearly manifests the presence of significant levels of protons in the hydrated material. Proton conductivity was investigated on prehydrated ͑under dry Ar͒ and as-prepared ͑under wet Ar͒ samples. The heating cycle of the prehydrated sample showed higher proton conductivity compared to the cooling cycle, especially in the intermediate temperature range ͑150-550°C͒. Finally, comparison with data for BaZr 0.9 Yb 0.1 O 3−␦ revealed that the more heavily doped sample showed higher proton conductivity compared to the more lightly doped sample.Increasing awareness of environmental factors coupled to a limited supply of energy resources has forced society to search for alternative clean energy sources. Fuel cells offer the possibility of directly converting chemical energy to electrical energy in an environmentally sustainable way. Low-temperature ͑T Ͻ 100°C͒ fuel cells, such as a polymer electrolyte fuel cell, where Nafion ͑perfluo-rosulfonic polymer͒ is used as the electrolyte, require expensive platinum catalysts. The high operating temperature of fuel cells based on oxide ion electrolytes leads to problems with material degradation and long start-up times. Therefore, fuel cells operating in an intermediate temperature range ͑200-500°C͒ are desirable alternatives.Generally, proton conducting materials are used as the electrolyte for intermediate temperature fuel cell ͑ITFC͒ due to their higher conductivity compared to oxide ion conducting materials in this temperature range. 1 Successive investigation and literature data compiled by Norby 2 show the presence of a "gap," within the intermediate temperature range, in which no electrolyte materials show sufficiently high proton conductivity. Low proton conductivity in the electrolyte materials has subdued the development of state-of-the-art ITFC. This motivates significant research efforts aimed at understanding and improving proton conducting properties in this key temperature range.Acceptor-doped alkaline earth perovskites are well-known proton-conducting ceramic materials. For example, Y-doped BaZrO 3 or BaCeO 3 are already known as very good proton conductors, reaching conductivities of ϳ10 −2 to 10 −3 S cm −1 at temperatures of ϳ300 to 600°C. 1,3-6 Cerates generally suffer from chemical instability under CO 2 containing atmospheres, readily forming alkaline earth carbonates according to 7,8 BaCeO 3 + CO 2 → BaCO 3 + CeO 2 ͓1͔In contrast, BaZrO 3 exhibits excellent stability under CO 2 . 8 Moreover, it has recently been recognized that 10 mol % Y-doped B...

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“…In this study we have chosen to investigate two state-of-theart perovskite-structured high temperature proton conductors; BaZr 0.9 Y 0.1 O 3 − δ (BZY10) [7,[18][19][20][21][22][23][24][25][26][27] and BaCe 0.9 Y 0.1 O 3 -δ (BCY10) [1,5,[28][29][30]. Both have been subject to numerous studies with respect to their structure, stability, defect chemistry, and transport properties.…”

Section: Introductionmentioning

confidence: 99%

Determination of the enthalpy of hydration of oxygen vacancies in Y-doped BaZrO3 and BaCeO3 by TG-DSC

et al. 2010

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Structural study and proton conductivity in Yb-doped BaZrO3

Cited by 60 publications

References 24 publications

Investigation of proton conductivity in Sm1.92Ca0.08Ti2O7−δ and Sm2Ti1.92Y0.08O7−δ pyrochlores

Investigation of proton conductivity in Sm1.92Ca0.08Ti2O7−δ and Sm2Ti1.92Y0.08O7−δ pyrochlores

Proton Conduction in Perovskite Oxide BaZr[sub 0.5]Yb[sub 0.5]O[sub 3−δ] Prepared by Wet Chemical Synthesis Route

Determination of the enthalpy of hydration of oxygen vacancies in Y-doped BaZrO3 and BaCeO3 by TG-DSC

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