Electrochemical evaluation of double perovskite PrBaCo2-xMnxO5+δ (x = 0, 0.5, 1) as promising cathodes for IT-SOFCs

Mn-substituted double perovskites , PrBaCo 2-x Mn x O 5+δ (x = 0, 0.5, 1), are evaluated as cathode materials for intermediate-temperature solid oxide fuel cells. The effects of Mn substitution content on their structural and electrochemical properties including crystal structure, thermal expansion coefficient , and cathodic interfacial polarization resistance are investigated. The PrBaCo 2-x Mn x O 5+δ samples exhibit structural changes with increasing Mn contents from tetragonal (x = 0) to cubic (x = 0.5 and 1.0) symmetry. The thermal expansion coefficient decreases with the increasing Mn content while the cathodic performance increases with the increment of Mn content from x = 0 to x = 0.5 then decreases with the further increment of Mn content from x = 0.5 to x = 1.0. When using La 0.8 Sr 0.2 Ga 0.8 Mg 0.15 Co 0.05 O 3 with 300 μm thickness as electrolyte and Sr 2 Fe 1.4 Ni 0.1 Mo 0.5 O 6-δ as anode, the maximum powder density of the x = 0.5 composite is 0.638 W cm −2 , which is higher than that of the other two samples with x = 0 (0.474 W cm −2 ) and x = 1.0 (0.371 W cm −2 ) at 800 °C.