Low Area Specific Resistance La-Doped BiO Nanocomposite Thin Film Cathodes for Solid Oxide Fuel Cell Applications.

In the context of solid oxide fuel cells (SOFCs), vertically aligned nanocomposite (VAN) thin films have emerged as a leading material type to overcome performance limitations in cathodes. Such VAN films combine conventional cathodes like LaSrCoFeO (LSCF) and LaSrMnO (LSM) together with highly O ionic conducting materials including yttria-stabilized zirconia (YSZ) or doped CeO. Next-generation SOFCs will benefit from the exceptionally high ionic conductivity (1 S cm at 730 °C) of BiO-based materials. Therefore, an opportunity exists to develop BiO-based VAN cathodes. Herein, we present the first growth and characterization of a BiO-based VAN cathode, containing epitaxial La-doped BiO (LDBO) columns embedded in a LSM matrix. Our novel VANs exhibit low area specific resistance (ASR) (8.3 Ω cm at 625 °C), representing ∼3 orders of magnitude reduction compared to planar LSM. Therefore, by demonstrating a high-performance BiO-based cathode, this work provides an important foundation for future BiO-based VAN SOFCs.