Correlation between phase structure and electrical conduction in BISNVOX system for intermediate temperature solid oxide fuel cells (IT-SOFC) |
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| Authors: | Saba Beg Shehla Hafeez Niyazi AS Al-Areqi |
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| Institution: | 1. Department of Chemistry , Aligarh Muslim University , Aligarh, U.P., India saba_beg@yahoo.com;3. Department of Chemistry , Aligarh Muslim University , Aligarh, U.P., India;4. Department of Chemistry , Aligarh Muslim University , Aligarh, U.P., India;5. Department of Chemistry, Faculty of Applied Sciences , Taiz University , Taiz, Republic of Yemen |
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| Abstract: | Samples of Sn4+-substituted bismuth vanadate, formulated as Bi4Sn x V2? x O11?( x /2)? δ in the composition range 0.07 ≤ x ≤ 0.30, were prepared by standard solid-state reactions. Sample characterization and the principal phase transitions (α ? β, β ? γ and γ′ ? γ) were investigated by FT-IR spectroscopy, X-ray powder diffraction, differential thermal analysis (DTA) and AC impedance spectroscopy. For composition x = 0.07, the α ? β and β ? γ phase transitions were observed at temperatures of 451 and 536°C, respectively. DTA thermograms and Arrhenius plots of conductivities revealed the γ′ ? γ phase transition at 411 and 423°C for x = 0.20 and 0.30, respectively. AC impedance plots showed that conductivity is mainly due to the grain contribution, which is evident in the enhanced short-range diffusion of oxide ion vacancy in the grains with increasing temperature. The highest ionic conductivity (5.03 × 10?5 S cm?1 at 300°C) was observed for the x = 0.17 solid solution with less pronounced thermal hysteresis. |
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| Keywords: | BIMEVOX phase transition AC impedance ionic conductivity |
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