Electrical conductivity and structural stability of La-doped SrTiO_3 with A-site deficiency as anode materials for solid oxide fuel cells

摘要

A-site-deficient (La_(0.3)Sr_(0.7))_(1-x)TiO_(3-δ) materials were synthesized by conventional solid-state reaction. The A-site deficiency limit in (La_(0.3)Sr_(0.7))_(1-x)TiO_(3-δ) was below 10 mol% in 5%H_2/Ar at 1500 ℃. A-site deficiency level promoted the sintering process of (La_(0.3)Sr_(0.7))_(1-x)TiO_(3-δ). The ionic conductivity increased but the electronic conductivity decreased with increasing A-site deficiency level. The ionic conductivity of (La_(0.3)Sr_(0.7))_(0.93)TiO_(3-δ) sample was as high as 0.2-1.6 × 10~(-2) S/cm in 500-950 ℃ and 1.0 × 10~(-2) S/cm at 800 ℃, over twice of La_(0.3)Sr_(0.7)TiO_(3-δ).rn Its electrical conductivity was in the range of 83-299 S/cm in 50-950 ℃ and 145 S/cm at 800 ℃. A-site deficiency improved the thermal stability of (La_(0.3)Sr_(0.7))_(1-x)TiO_(3-δ) and ensured the material with a stable electrical performance in different atmospheres.