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- Title
Transport, thermomechanical, and electrode properties of perovskite-type $$ {\left( {{\hbox{L}}{{\hbox{a}}_{0.{75} - x}}{\hbox{S}}{{\hbox{r}}_{0.{25} + x}}} \right)_{0.{95}}}{\hbox{M}}{{\hbox{n}}_{0.{5}}}{\hbox{C}}{{\hbox{r}}_{0.{5} - x}}{\hbox{T}}{{\hbox{i}}_x}{{\hbox{O}}_{{3} - }}_\delta \left( {x = 0 - 0.{5}} \right) $$
- Authors
Kolotygin, Vladislav A.; Tsipis, Ekaterina V.; Shaula, Aliaksandr L.; Naumovich, Eugene N.; Frade, Jorge R.; Bredikhin, Sergey I.; Kharton, Vladislav V.
- Abstract
Increasing Sr and Ti concentrations in perovskite-type $$ {\left( {{\hbox{L}}{{\hbox{a}}_{0.{75} - x}}{\hbox{S}}{{\hbox{r}}_{0.{25} + x}}} \right)_{0.{95}}}{\hbox{M}}{{\hbox{n}}_{0.{5}}}{\hbox{C}}{{\hbox{r}}_{0.{5} - x}}{\hbox{T}}{{\hbox{i}}_x}{{\hbox{O}}_{{3} - }}_\delta \left( {x = 0 - 0.{5}} \right) $$ results in slightly higher thermal and chemical expansion, whereas the total conductivity activation energy tends to decrease. The average thermal expansion coefficients determined by controlled-atmosphere dilatometry vary in the range (10.8-14.5) × 10 K at 373-1,373 K, being almost independent of the oxygen partial pressure. Variations of the conductivity and Seebeck coefficient, studied in the oxygen pressure range 10-0.5 atm, suggest that the electronic transport under oxidizing and moderately reducing conditions is dominated by p-type charge carriers and occurs via a small-polaron mechanism. Contrary to the hole concentration changes, the hole mobility decreases with increasing x. The oxygen permeation fluxes through dense ceramic membranes are quite similar for all compositions due to very low level of oxygen nonstoichiometry and are strongly affected by the grain-boundary diffusion and surface exchange kinetics. The porous electrodes applied onto lanthanum gallate-based solid electrolyte exhibit a considerably better electrochemical performance compared to the apatite-type LaSiAlO electrolyte at atmospheric oxygen pressure, while Sr and Ti additions have no essential influence on the polarization resistance. In H-containing gases where the electronic transport in $$ {\left( {{\hbox{L}}{{\hbox{a}}_{0.{75} - x}}{\hbox{S}}{{\hbox{r}}_{0.{25} + x}}} \right)_{0.{95}}}{\hbox{M}}{{\hbox{n}}_{0.{5}}}{\hbox{C}}{{\hbox{r}}_{0.{5} - x}}{\hbox{T}}{{\hbox{i}}_x}{{\hbox{O}}_{{3} - }}_\delta $$ perovskites becomes low, co-doping deteriorates the anode performance, which can be however improved by infiltrating Ni and $$ {\hbox{Ce}}{{\hbox{O}}_{{\rm{2}} - }}_\delta $$v into the porous oxide electrode matrix.
- Subjects
THERMOMECHANICAL properties of metals; PEROVSKITE; ELECTRODES; ELECTROLYTIC oxidation; ELECTRIC conductivity; ELECTROCHEMISTRY
- Publication
Journal of Solid State Electrochemistry, 2011, Vol 15, Issue 2, p313
- ISSN
1432-8488
- Publication type
Article
- DOI
10.1007/s10008-010-1203-9