Charge carriers in grain boundaries of 0.5% Sr-doped LaNbO4

Fjeld, Harald; Kepaptsoglou, Demie; Haugsrud, Reidar; Norby, Truls

doi:10.1016/j.ssi.2009.04.019

Cited by 65 publications

(50 citation statements)

References 16 publications

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“…8 and SI Fig. 1), often identifies the grain boundary as blocking in the LaNbO4 based ionic conductors 60 . Albeit the fast grain boundary oxygen diffusion is not in contrast with the low specific grain boundary conductivity reported using impedance spectroscopy as the isotopic exchange technique is only sensitive to the ionic contribution from oxygen whereas the total conductivity measured by impedance is predominantly p-type or protonic in other acceptor doped systems.…”

Section: Discussionmentioning

confidence: 99%

Influence of Sb-substitution on ionic transport in lanthanum orthoniobates

et al. 2016

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The results of ionic transport measurements for the lanthanum orthoniobate substituted with 10 and 30 mol% of antimony (LaNb0.9Sb0.1O4 and LaNb0.7Sb0.3O4) are presented and discussed. The influence of calcium co-doping on these properties has also been analysed. It has been shown that for the investigated material protonic conductivity predominates at temperatures up to 800 °C in oxidizing atmospheres, in wet conditions. Maximum observed protonic conductivity reaches ~10-4 S/cm at 800 °C (in humidified air); in the dry conditions the increasing influence of oxygen vacancies and holes is detected. Oxygen self-diffusivity has also been analysed by isotopic exchange to investigate the possible diffusion paths.

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Section: Discussionmentioning

confidence: 99%

Influence of Sb-substitution on ionic transport in lanthanum orthoniobates

et al. 2016

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“…14 Investigation of their electrical properties showed that both polymorphs exhibit protonic conduction with lower activation energies for the t-LaNbO 4 . 24,25 Stable sites for protons and their migration paths were correlated to the electrical properties of these two polymorphs, suggesting an almost double potential barrier (150 kJ/mol) for proton out-of-plane migrations in m-LaNbO 4 compared to the t-LaNbO 4 . 25 In its pure form, lanthanum niobate exhibits rather poor conductivity with protonic contribution in the range of 10 −5 S/cm at 800 • C in humid H 2 .…”

Section: Introductionmentioning

confidence: 99%

“…26 Along with other ceramic materials such as BaZrO 3 , 27 SrTiO 3 , 28 CeO 2 and ZrO 2 , 29-32 LaNbO 4 reveals high inherent grain boundary (GB) resistivity originating from mobile charge depletion in the GB regions. 24 Therefore, acceptor doping is typically required to improve the electrical and GB interfacial properties (in particular the protonic conductivity) of niobates as demonstrated in Refs. [14][15][16].…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, these could be used intentionally to "decorate" material interfaces and thus, to improve the grain boundary conductivity, which in the case of niobates shows an inherently low magnitude. 24 The present work is dedicated to the development of co-doped compounds within the series La 0.99 X 0.01 Nb 0.99 Al 0.01 O 4−δ and La 0.99 X 0.01 Nb 0.99 Ti 0.01 O 4−δ (X = Mg, Ca, Sr, Ba) and the screening of their functional properties in a search for novel proton and mixed proton-electronic conductors for possible application in PCFCs and H 2 -separation. Al 3+ and Ti 4+ ions were selected as B-site dopants for the different net concentration of defects they would generate by keeping the A-site dopant equal.…”

Section: Introductionmentioning

confidence: 99%

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Functional properties of La0.99X0.01Nb0.99Al0.01O4−δ and La0.99X0.01Nb0.99Ti0.01O4−δ proton conductors where X is an alkaline earth cation

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et al. 2015

Journal of the European Ceramic Society

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“…The overall total conductivity of several ion conducting oxides is strongly affected by the grain size, and thus the grain boundary density, since grain boundaries can act as a barrier for ion transport [9,[13][14][15][16]. For SLNT pellets, the correlation between conductivity and grain size was investigated by comparing the statistical descriptors (average, mode, median and standard deviation) with the conductivity at 500°C.…”

Section: Resultsmentioning

confidence: 99%

Tailoring phase stability and electrical conductivity of Sr0.02La0.98Nb1–xTaxO4 for intermediate temperature fuel cell proton conducting electrolytes

et al. 2012

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a b s t r a c t a r t i c l e i n f oO 4 (SLNT, with x = 0.1, 0.2, and 0.4) proton conducting oxides were synthesized by solid state reaction for application as electrolyte in solid oxide fuel cells operating below 600°C. Dense pellets were obtained after sintering at 1600°C for 5 h achieving a larger average grain size with increasing the tantalum content. Dilatometric measurements were used to obtain the SLNT expansion coefficient as a function of tantalum content (x), and it was found that the phase transition temperature increased with increasing the tantalum content, being T = 561, 634, and 802°C for x = 0.1, 0.2, and 0.4, respectively. The electrical conductivity of SLNT was measured by electrochemical impedance spectroscopy as a function of temperature and tantalum concentration under wet (p H2O of about 0.03 atm) Ar atmosphere. At each temperature, the conductivity decreased with increasing the tantalum content, at 600°C being 2.68 × 10 −4 , 3.14 × 10 −5 , and 5.41 × 10 −6 Scm −1 for the x = 0.1, 0.2, and 0.4 compositions, respectively. SLNT with x = 0.2 shows a good compromise between proton conductivity and the requirement of avoiding detrimental phase transitions for application as a thin-film electrolyte below 600°C.

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Charge carriers in grain boundaries of 0.5% Sr-doped LaNbO4

Cited by 65 publications

References 16 publications

Influence of Sb-substitution on ionic transport in lanthanum orthoniobates

Influence of Sb-substitution on ionic transport in lanthanum orthoniobates

Functional properties of La0.99X0.01Nb0.99Al0.01O4−δ and La0.99X0.01Nb0.99Ti0.01O4−δ proton conductors where X is an alkaline earth cation

Tailoring phase stability and electrical conductivity of Sr0.02La0.98Nb1–xTaxO4 for intermediate temperature fuel cell proton conducting electrolytes

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