Effect of Mn on the characterization of layered perovskite NdBaCo2-xMnxO5+δ (x=0.5, 1, 1.5, 2) as cathode materials for IT-SOFCs

Abstract

NdBaCo2-xMnxO5+δ\ (x=0.5, 1, 1.5, 2) samples are synthesized via sol-gel method. The effect of Mn on the crystal structure, thermal expansion, electrical conductivity and electrochemical properties of NdBaCo2-xMnxO5+δ (x=0.5, 1, 1.5, 2) have been investigated. The lattice parameter of NdBaCo2-xMnxO5+δ decreases when Mn increasing. The substitution of Mn for Co significantly lowers the thermal expansion coefficient (TEC) which consequently improves the mechanical compatibility with the electrolyte SDC. Although the electrical conductivity and the electrochemical performances of NdBaCo2-xMnxO5+δ (x=0.5, 1, 1.5, 2) decrease with Mn increasing, NdBaCo1.5Mn0.5O5+δ and NdBaCoMnO5+δ have better electrochemical performance and the Rp are 0.07Ocm2 and 0.10Ocm2 at 800°C respectively, which can accord with the electrochemical performance requirement of IT-SOFCs cathode materials. NdBaCoMnO5+δ provides a tradeoff relationship between TEC and electrochemical performance.