ИСТИНА

Solid oxide fuel cells (SOFCs), a type of electrochemical devices converting chemical energy directly to electric power through a clean electrochemical process. They are regarded as environmentally friendly, high efficiency and low cost because they do not contain precious metal. Recently, symmetrical SOFCs (SSOFCs), where anode and cathode materials are the same, have received increasing interest owing to the fact that such symmetrical configuration can substantially simplify the manufacture process of SOFCs [1,2]. In the current work high-temperature electrical conductivity properties of the novel perovskites La1-yCayFe0.5+x(Mg,Mo)0.5-xO3- which was measured in the air and Ar/H2 (8%) at 300-900oC are discussed. All samples demonstrate temperature activated electrical conductivity below 10 S/cm at 900oC in air. The highest electrical conductivity is observed for La0.3Ca0.7Fe0.6Mo0.225Mg0.175O3- sample with electrical conductivity of 6.1 S/cm at 900oC. Electrical conductivity was found to increase with Ca- and Fe-content. The electrical conductivity versus temperature can be satisfactorily fitted with a model of a small polaron charge transport, which is known to be a most adequate model for the explanation of the transport properties of the perovskite-related oxides with 3d-metal cations. In reducing atmosphere in all temperature range electrical conductivity of La0.3Ca0.7Fe0.6Mo0.225Mg0.175O3- is lower in comparison with in the air. It demonstrates maximum at 800oC with the conductivity value of =3.5 S/cm. It should be mentioned that electrical conductivity of La0.3Ca0.7Fe0.6Mo0.225Mg0.175O3- at 900oC is =1.9 S/cm and is enough for its application as electrode material is symmetrical SOFC.