La and Sc co-doped SrTiO3 as novel anode materials for solid oxide fuel cells

La and Sc co-doped SrTiO3 was synthesized via solid state reaction. The oxygen ion migration energy was investigated by first-principles calculations in SrBO3 systems (B = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Zn, Ga, Ge, As, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Cd, In, Sn and Sb) with perovskite structure. Structure with Sc showed the lowest oxygen migration energy, and thus Sc was selected as B-site dopant with the primary aim to improve the ionic conductivity of SrTiO3-based anode materials. With increasing Sc-doping amount, the electrical conductivity of La0.3Sr0.7ScxTi1−xO3−δ decreased in 25–1000 °C, while the ionic conductivity increased significantly between 500 and 1000 °C. The ionic conductivity for La0.3Sr0.7Sc0.10Ti0.90O3−δ was 1 × 10−2 S cm−1 and increased about 230% compared with La0.3Sr0.7TiO3−δ at 800 °C and under oxygen partial pressure of 10−19 atm. Sc-doping increased the oxygen vacancy concentration and decreased the oxygen migration energy, thus facilitating the conduction process of oxygen ions in La and Sc co-doped SrTiO3. The possible charge compensation mechanism of Sc-doped La0.3Sr0.7TiO3−δ   can be described as La0.3Sr0.7Scx3+Ti0.7-2δ-x14+Ti0.3+2δ-x23+O3-(δ+x1/2) (x = x1 + x2).