High Performance Tubular Solid Oxide Fuel Cell Based on Ba 0.5 Sr 0.5 Ce 0.6 Zr 0.2 Gd 0.1 Y 0.1 O 3-δ Proton Conducting Electrolyte

Abstract

© 2018 The Electrochemical Society. In this work, synthesis and characterization of an anode supported tubular solid oxide fuel cell based on Ba0.5Sr0.5 Ce0.6Zr0.2Gd0.1Y0.1O3-δ (BSCZGY) electrolyte has been investigated. Anode-supported Ni - yttria-stabilized zirconia (YSZ) anode was fabricated via slip casting; BSCZGY electrolyte and BSCZGY - La0.6Sr0.4Co0.2Fe0.8O3 (LSCF) composite cathode were coated on support using dip coating, respectively. The chemical compatibility of fuel cell components at sintering temperatures has been investigated by powder X-ray diffraction, and no severe reactions were detected. Electrochemical examination under air/H2 + 3 vol. % H2O showed superior performance achieving a maximum power density of 1 W/cm2 at 850°C, among the best compared to tubular - geometry oxygen conductor solid oxide fuel cells reported earlier and one of the highest reported for a proton conductor electrolyte in literature. Electrochemical impedance spectroscopy was used to examine the electrochemical performance of the full cell at different temperatures, and a detailed analysis was done to distinguish the contribution of ohmic and polarization resistances of the cell. ASR values were 3.47 Ω.cm2, 1.81 Ω.cm2, 1.23 Ω.cm2, and 1.05 Ω.cm2 at 600, 700, 800, and 850°C, respectively. Analysis of activation energy associated with charge and mass transfer based on fitting of impedances revealed that concentration polarization is the major contributor to the total resistance. The long-term stability for more than 96 hours of operation under load showed no significant degradation, which demonstrated the steady behavior of the cell.