Effect of calcium doping on La4(Ti2O8)O2 structure and conductivity

Cioateră, Nicoleta; Voinea, Elena-Adriana; Kehal, I.; Rolle, Aurélie; Spinu, C.I.; Vannier, R-N.

doi:10.1016/j.jallcom.2016.02.017

Cited by 1 publication

(2 citation statements)

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“…As a representative case, several authors took advantages of the La 4 (Ga 2 O 7 )O 2 cuspidine structure and carried out donor doping to partially fill the vacant positions among M 2 O 7 units, to then optimize their oxide ion conductivity. , The monoclinic La 4 (Ga 2 O 7 )O 2 phase (S.G. P 2 1 / c ) becomes orthorhombic (S.G. Pnam ) by completely filling the oxygen vacancies through Ti substitution for Ga, leading to La 4 (Ti 2 O 8 )O 2 , which adopts the same structural framework but with corner-sharing trigonal bipyramidal Ti 2 O 8 chains (Figure c,d) . Alternatively, starting from the La 4 (Ti 2 O 8 )O 2 composition, the acceptor doping results in oxygen vacancies, which promotes oxide ion conduction . Therefore, oxy-cuspidines can be rewritten as the general formula A 4 ( M 2 O 8– x □ x )O 2 ( A = lanthanides, M = Al, Ga, Ti, Ge) to represent a larger family containing the mixed tetrahedral/bipyramidal M 2 O 8– x units, which are isolated tetrahedral dimers M 2 O 7 or corner-sharing bipyramidal chains M 2 O 8 for x = 1 and x = 0 end members, respectively.…”

Section: Cuspidine-type Oxide Ion Conductorsmentioning

confidence: 99%

“…Nevertheless, the maximum conductivity never exceeded 10 –3 S·cm –1 at 800 °C. A different doping strategy was employed by Cioatera et al, who doped the A site with Ca to introduce the oxygen vacancies in La 4– x Ca x Ti 2 O 10–0.5 x . This strategy resulted in the highest conductivity reported for an oxy-cuspidine-type material so far, achieving 1.65 × 10 –2 S·cm –1 at 800 °C for La 3.8 Ca 0.2 Ti 2 O 9.9 composition.…”

Section: Cuspidine-type Oxide Ion Conductorsmentioning

confidence: 99%

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Oxide Ion-Conducting Materials Containing Tetrahedral Moieties: Structures and Conduction Mechanisms

2023

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This Review presents an overview from the perspective of tetrahedral chemistry on various oxide ion-conducting materials containing tetrahedral moieties which have received continuous growing attention as candidates for key components of various devices, including solid oxide fuel cells and oxygen sensors, due to the deformation and rotation flexibility of tetrahedral units facilitating oxide ion transport. Emphasis is placed on the structural and mechanistic features of various systems ranging from crystalline to amorphous materials, which include a variety of gallates, silicates, germanates, molybdates, tungstates, vanadates, aluminates, niobate, titanates, indium oxides, and the newly reported borates. They contain tetrahedral units in either isolated or linked manners forming different polyhedral dimensionality (0 to 3) with various defect properties and transport mechanisms. The development of oxide ion conductors containing tetrahedral moieties and the elucidation of the roles of tetrahedral units in oxide ion migration have demonstrated diverse opportunities for discovering superior electrolytes for solid oxide fuel cells and other related devices and provided useful clues for uncovering the key factors directing fast oxide ion conduction.

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