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−δ whose maximum conductivity is 7.6×10−3 S cm−1 at 900°C. The electrical conductivity of La0.9Sr0.1InO3−δ has been measured over a wide range of oxygen partial pressure from pO2=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−δ ceramic pellet has been tested. A maximum power density of 3 mW cm−2 at 800°C was achieved when dilute H2 and air were used as fuel and oxidizing agent, respectively.