A nanocomposite material for highly durable solid oxidefuel cell cathodes

Abstract

We have synthesized well-engineered nanocomposite particles for the achievement of highly durable solid oxide fuel cell cathodes. The use of a dual-composite approach in which both LSM and YSZ phases are placed on a YSZ grain allows for the development of an ideal cathode microstructure with improved phase contiguity and interfacial coherence. Microstructural observations in conjunction with impedance analysis during accelerated lifetime tests clearly reveal that three-dimensionally interconnected percolative networks of both electronic and ionic conduction give cells based on the dual-composite cathode better long-term stability. A cell with such a well-controlled cathode maintains nearly constant power density over 500 h. In contrast, a cathode prepared by mechanical mixing undergoes significant degradation during the stability test due to thermochemically and electrochemically driven coarsening and shrinkage of the LSM phase.