perovskite, cobalt oxide, solid solution, electrical conductivity, thermoelectric
In this work, we synthesized cubic perovskite ceramics of the whole La1–xSrxCoO3 (0 ≤ x ≤ 1) solid solution for the first time. Synthesis was carried out by solid state reaction and conventional sintering to reach dense ceramics. For x > 0.8, it was necessary to substitute 3% cobalt by silicon to stabilize the cubic perovskite structure. Electrical conductivity increased with Sr content to reach 3×105 S·m–1 at 330 K for x = 0.3. However, the optimum electrical properties have been found for x = 0.05 at 330 K with PFmax = 3.11×10–4 W·m–1·K–2. Indeed, the Seebeck coefficient was decreasing when x increased to reach values close to 0 for x ≥ 0.3. Thermal conductivity was low at low temperature (≈ 2.5 W·m–1·K–1) and increased up to 6.5 W·m–1·K–1 when temperature increased. As the highest power factor was reached at low temperature as well as the lowest thermal conductivity, La1–xSrxCoO3 compounds with low x values appeared as very promising thermoelectric materials around room temperature, on the contrary to layered cobalt oxides. For high x values, Seebeck coefficient values close to zero made these materials unsuitable for thermoelectric applications.
Tsinghua University Press
M. A. BOUSNINA, R. DUJARDIN, L. PERRIERE et al. Synthesis, sintering, and thermoelectric properties of the solid solution La1–xSrxCoO3±δ (0 ≤ x ≤ 1). Journal of Advanced Ceramics 2018, 07(02): 160-168.