A novel cobalt-free double-perovskite NdBaFe1.9Nb0.1O5+δ cathode material for proton-conducting IT-SOFC

A novel cobalt-free double-perovskite oxide NdBaFe 1.9 Nb 0.1 O 5+ δ (NBFNb10) was prepared by a solid-state reaction method and investigated as a suitable cathode material for intermediate temperature solid oxide fuel cells (IT-SOFCs). It was discovered that partial substitution of Nb for Fe-site further enhanced the electrical conductivity of NdBaFe 2 O 5+ δ (NBF). The NBFNb10 exhibited the highest conductivity of 109   S   cm −1 at 300–800   °C in air, and showed good chemical compatibility with the BaZr 0.1 Ce 0.7 Y 0.2 O 3− α (BZCY) electrolyte. A single cell with the NBFNb10–BZCY composite cathode and NiO–BZCY composite anode-supported BZCY electrolyte membrane (ca. 30   μm thickness) was fabricated and tested at 500–700   °C using H 2 as fuel and air as oxidant. The peak power density and the interfacial polarization resistance ( R p ) were 392   mW   cm −2 and 0.14   Ω   cm 2 at 700   °C, respectively.