Gradient Anode Functional Layer for Thin Y:BaZr_xCe_1-XO₃ Electrolyte in Low-Temperature Solid Oxide Fuel Cells

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.