Gradient Anode Functional Layer for Thin Y:BaZrxCe1-XO3 Electrolyte in Low-Temperature Solid Oxide Fuel Cells

Tuesday, 28 July 2015
Hall 2 (Scottish Exhibition and Conference Centre)
K. Bae (Korea University, Korea Institute of Science and Technology), S. Lee (Hanyang University), D. Y. Jang, H. J. Kim (Korea University), H. Lee, D. Shin (Hanyang University), J. W. Son (Korea Institute of Science and Technology), and J. H. Shim (Korea University)
Many studies have shown the great potential of proton-conducting yttrium-doped barium cerate (BCY) as a next-generation ceramic electrolyte for low-temperature solid oxide fuel cells (LT-SOFCs), but BCY’s poor chemical stability has limited its practical use. Research has confirmed that yttrium-doped barium cerate-zirconate (BCZY), substituting Zr in the B-site of BCY, can significantly mitigate the degradation of the material with little sacrifice of electrical and electrochemical performances. For successful operation of LT-SOFCs with BCZY electrolytes, the deposition of the material as a thin film and the reduction of ohmic overpotential from ion transport are necessary. In this work, we propose a novel anode design suitable for thin BCZY electrolytes (thickness < 2 μm) with a continuously gradient anode functional layer (AFL). The base BCZY powder was synthesized by the citric-nitrate method with a composition of BaCe0.5Zr0.35Y0.15O3-δ. Electrostatic slurry spray deposition (ESSD) was used to form the gradient AFL on a porous anode support and co-sintered at 1500°C. A thin, dense BCZY electrolyte was fabricated on the sintered AFL by pulsed laser deposition (PLD) at 700°C. As the cathode, porous La0.6Sr0.4CoO3-δ was deposited by PLD at room temperature. Fuel cell tests were conducted and the maximum power output of 180‒580 mW/cm2 at 450‒600°C was identified. The performance and electrochemical characteristics of the BCZY-SOFCs will be discussed in greater depth at the conference.