Electrochemical performance of double-perovskite Ba2MMoO6 (M = Fe, Co, Mn, Ni) anode materials for solid oxide fuel cells

Double-perovskite Ba2MMoO6 (M = Fe, Co, Mn, Ni) has been systematically investigated as anode materials for solid oxide fuel cells (SOFCs). Among these materials, Ba2FeMoO6 shows the best electrochemical performance with maximum power density of 605 mW cm−2 and electronic conductivity of 196 S cm−1 at 850 °C in H2. Thermal expansion coefficients of Ba2MMoO6 are distributed within the range of (10 − 18) × 10−6 K−1, matching well with that of La0.8Sr0.2Ga0.83Mg0.17O3−δ electrolyte. Thermogravimetric analysis (TGA) clearly indicates that oxygen vacancies are formed in all the Ba2MMoO6 materials. For the Ba2MMoO6 anodes, the power output decreases in the order of M = Fe > M = Co > M = Mn > M = Ni; the overpotential increases in the order of M = Fe < M = Co < M = Mn < M = Ni; and the impedance varies in the order of M = Co < M = Fe < M = Mn < M = Ni. The different performance for this family is ascribed to the difference in conductivity and oxygen vacancy.

► Double-perovskite Ba2MMoO6 (M = Fe, Co, Mn, Ni) has been investigated as anode materials for solid oxide fuel cells. ► Ba2FeMoO6 shows the best electrochemical performance with maximum power density of 605 mW cm−2 at 850 °C in H2. ► Ba2MMoO6 exhibits matchable thermal expansion with intermediate-temperature La0.8Sr0.2Ga0.83Mg0.17O3−δ electrolyte. ► Conductivity and oxygen vacancy play important roles in electrochemical performance.