Low Area Specific Resistance La-Doped Bi2O3 Nanocomposite Thin Film Cathodes for Solid Oxide Fuel Cell Applications.

Abstract

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 LaxSr1-xCoyFe1-yO3 (LSCF) and La1-xSrxMnO3 (LSM) together with highly O2- ionic conducting materials including yttria-stabilized zirconia (YSZ) or doped CeO2. Next-generation SOFCs will benefit from the exceptionally high ionic conductivity (1 S cm-1 at 730 °C) of Bi2O3-based materials. Therefore, an opportunity exists to develop Bi2O3-based VAN cathodes. Herein, we present the first growth and characterization of a Bi2O3-based VAN cathode, containing epitaxial La-doped Bi2O3 (LDBO) columns embedded in a LSM matrix. Our novel VANs exhibit low area specific resistance (ASR) (8.3 Ω cm2 at 625 °C), representing ∼3 orders of magnitude reduction compared to planar LSM. Therefore, by demonstrating a high-performance Bi2O3-based cathode, this work provides an important foundation for future Bi2O3-based VAN SOFCs.