Examination of Morphological and Chemical Properties of Ni-BZY Anodes and their Influence upon Methane Reactivity and Electrochemical Performance of Protonic-Ceramic Fuel Cells

Abstract

Ni-BZY (yttrium-doped barium zirconate) has drawn recent interest for application in protonic ceramic fuel cells (PCFCs) due to BZY’s superior protonic conductivity and stability in reforming environments containing CO2 and H2O. Additionally, Ni and BZY form unique nano/microstructures thought to synergistically facilitate reforming. While PCFCs with Ni-BZY anodes have demonstrated stable long-term performance, little is known about the material’s transformations during operation and subsequent impact on electrochemical metrics. To address this knowledge gap, we constructed PCFCs consisting of Ni-BZY anodes sintered onto a ~600 μm BZY electrolyte complete with a LSCF/BCZY cathode. The electrochemical performance of these cells is compared at 600-700 °C while operating with humidified hydrogen, neat methane, and steam reformed methane (1CH4:1H2O). Insights into morphological and chemical changes are provided by pre- and post-mortem analysis of the anode via Raman spectroscopy, X-ray diffraction, and SEM. Phase transformations, agglomeration and coking all appeared to contribute to performance degradation.