Synthesis and Characterization of Ceria- and Samaria-Based Powders and Solid Electrolytes as Promising Components of Solid Oxide Fuel Cells

Finely dispersed (CeO2)0.95(Sm2O3)0.05, (CeO2)0.90(Sm2O3)0.10 and (CeO2)0.80(Sm2O3)0.20 mesoporous powders with a specific pore volume of 0.080–0.092 cm3/g and a specific surface of 50–83 m2/g are synthesized by the co-precipitation of cerium and samarium hydroxides from the corresponding nitrate solutions. The prepared powders are used to obtain ceramic nanomaterials with a fluorite-like cubic crystal lattice with a coherent scattering region (CSR) of about 65–69 nm (1300 °C). The study of physicochemical and electrophysical properties of the prepared ceramics revealed the obtained materials featuring an open porosity of 2–6% and a predominantly ionic type of electric conductivity (ion transport numbers ti = 0.85–0.73 in the temperature range 300–700 °C). The conductivity in solid solutions proceeds via a vacancy mechanism with σ700 °C= 3.3·10−2 S/cm. The synthesized ceramic materials are shown to be promising as solid oxide electrolytes in medium temperature fuel cells

Synthesis and Investigation of Ceramic Materials for Medium-Temperature Solid Oxide Fuel Cells

Finely dispersed (СeO2)1-x(Sm2O3)x (x = 0.02; 0.05; 0.10); La1-xSrxNiO3, La1-xSrxCoO3 and La1-xSrxFe0.7Ni0.3O3 (x = 0.30; 0.40) mesoporous xerogel powders are synthesized by co-crystallization of the corresponding nitrates with ultrasonic processing and used to obtain nanoscale ceramic materials with cubic fluorite-like, orthorhombic, and perovskite-like tetragonal crystal structure, respectively, with CSR ∼ 64–81 nm (1300°C). Physicochemical characterization of the obtained ceramics revealed that (СeO2)1-x(Sm2O3)x features with open porosity 2–6%, while for La1-xSrxNiO3, La1-xSrxCoO3, and La1-xSrxFe0.7Ni0.3O3, this value is about 21–29%. Ceria-based materials possess a predominantly ionic conductivity (ion transport numbers ti = 0.82–0.71 in the temperature range 300–700°C, σ700°С = 1.3·10−2 S/cm) determined by the formation of mobile oxygen vacancies upon heterovalent substitution of Sm3+ for Се4+. For solid solutions based on lanthanum nickelate and cobaltite, a mixed electronic-ionic conductivity (σ700°С = 0.80·10−1 S/cm) with ion transport numbers (te = 0.98–0.90, ti = 0.02–0.10) was obtained. The obtained ceramic materials are shown to be promising as solid oxide electrolytes and electrodes for medium-temperature fuel cells