TY - JOUR

T1 - Structural and electric properties of the Ce 0.8(Sm 1-xCa x) 0.2O 2-δ System (x = 0.0-1.0)

AU - Pikalova, E. Yu

AU - Murashkina, A. A.

AU - Medvedev, D. A.

N1 - Funding Information: The work was financially supported by the Russian Foundation for Basic Research (project no. 09 03 00181).

PY - 2011

Y1 - 2011

N2 - CeO 2-based solid solutions with a fluorite structure are promising materials as electrolytes of medium-temperature electrochemical devices. This work presents the results of systematic studies of structural and electric properties and oxygen nonstoichiometry of the Ce 0.8(Sm 1-xCa x) 0.2O 2-δ system in a wide range of concentrations of 0 < x < 1 performed in order to establish the causes affecting the system conductivity and its behavior in a reducing medium. It is found that a single-phase solid solution of the fluorite type is formed in the whole concentration range. Parameters of its lattice cells decrease linearly at an increase in the concentration of Ca 2+. Conductivity in air grows when calcium is added due to a decrease in the grain boundary resistance. The maximum conductivity in air was obtained for the composition of Ce 0.8(Sm 0.8Ca 0.2) 0.2O 2-δ and is 13.71 × 10 -3 S/cm at 873 K. Studies of the dependence of conductivity of the partial pressure of oxygen showed that electron conductivity is observed at a higher oxygen partial pressure at an increase in the temperature and calcium concentration. The critical partial pressure of oxygen (PO* 2) for the compositions of Ce 0.8(Sm 1-xCa x) 0.2O 2-δ with x = 0; 0.2, and 0.5 is 1.83 × 10 -16, 1.73 × 10 -13, and 3.63 × 10 -13 atm at 1173 K, respectively, and 2.76 × 10 -21, 5.05 × 10 -18, and 1.31 × 10 -18 atm at 1023 K.

AB - CeO 2-based solid solutions with a fluorite structure are promising materials as electrolytes of medium-temperature electrochemical devices. This work presents the results of systematic studies of structural and electric properties and oxygen nonstoichiometry of the Ce 0.8(Sm 1-xCa x) 0.2O 2-δ system in a wide range of concentrations of 0 < x < 1 performed in order to establish the causes affecting the system conductivity and its behavior in a reducing medium. It is found that a single-phase solid solution of the fluorite type is formed in the whole concentration range. Parameters of its lattice cells decrease linearly at an increase in the concentration of Ca 2+. Conductivity in air grows when calcium is added due to a decrease in the grain boundary resistance. The maximum conductivity in air was obtained for the composition of Ce 0.8(Sm 0.8Ca 0.2) 0.2O 2-δ and is 13.71 × 10 -3 S/cm at 873 K. Studies of the dependence of conductivity of the partial pressure of oxygen showed that electron conductivity is observed at a higher oxygen partial pressure at an increase in the temperature and calcium concentration. The critical partial pressure of oxygen (PO* 2) for the compositions of Ce 0.8(Sm 1-xCa x) 0.2O 2-δ with x = 0; 0.2, and 0.5 is 1.83 × 10 -16, 1.73 × 10 -13, and 3.63 × 10 -13 atm at 1173 K, respectively, and 2.76 × 10 -21, 5.05 × 10 -18, and 1.31 × 10 -18 atm at 1023 K.

KW - Cerium dioxide

KW - Electrolytic properties

KW - Impedance spectroscopy

KW - Nonstoichiometry

KW - Oxygen-ion conductivity

KW - Solid oxide electrolytes

UR - http://www.scopus.com/inward/record.url?scp=84856248357&partnerID=8YFLogxK

U2 - 10.1134/S1023193511060115

DO - 10.1134/S1023193511060115

M3 - Article

AN - SCOPUS:84856248357

VL - 47

SP - 681

EP - 689

JO - Russian Journal of Electrochemistry

JF - Russian Journal of Electrochemistry

SN - 1023-1935

IS - 6

ER -