Continuously gradient anode functional layer for BCZY based proton-conducting fuel cells

Abstract

This study examined the effects of a continuously gradient anode functional layer (AFL) on the performance of the BaCe0.5Zr0.35Y0.15O3−δ (BCZY) based proton conducting fuel cell. The gradient AFL composed of NiO and BCZY was fabricated by the electrostatic slurry spray deposition (ESSD) technique with a rotation stage. For the comparison, the single cells without AFL and with homogeneous AFL were also prepared and the electrochemical properties were evaluated by full cell test and electrochemical impedance spectroscopy (EIS). Power density of the single cell with the gradient AFL exhibited 521 mW/cm2 at 700 °C which was higher by 48% and 16% compared to single cells without the AFL and with the homogeneous AFL. In addition, impedance spectra showed that both ohmic and polarization resistances under open circuit voltage (OCV) at 700 °C decreased from 0.3218 and 0.3462 to 0.2168 and 0.2203 Ωcm2. This performance enhancement is primarily attributed to modified microstructure of the AFL which has a continuously gradient interface to effectively reduce a mismatch between electrolyte and anode.