Sr-doped LaInO3 and its possible application in a single layer SOFC

The effects of dopants on the electrical conductivity of the perovskite-type oxide LaInO3 have been investigated. Replacement of La by Sr is the most effective way to enhance the conductivity of LaInO3, whereas Ca substitution for In is rather difficult due to the large difference in the ion radii. The optimum composition is La0.9Sr0.1InO3-delta whose maximum conductivity is 7.6 X 10(-3) S cm(-1) at 900 degrees C. The electrical conductivity of La0.9Sr0.1InO3-delta has been measured over a wide range of oxygen partial pressure from pO(2) =1 to 10(-25) atm. P-type and n-type behavior at high and low oxygen partial pressure have been observed, respectively, while at intermediate oxygen partial pressures, the electrical conductivity changes only slightly with the oxygen partial pressure. The concept of a single layer solid oxide fuel cell based on a La0.9Sr0.1InO3-delta ceramic pellet has been tested. A maximum power density of 3 mW cm(-2) at 800 degrees C was achieved when dilute H-2 and air were used as fuel and oxidizing agent, respectively. (C) 2000 Elsevier Science B.V. All rights reserved.