Enhanced Performance of Gadolinia-Doped Ceria Diffusion Barrier Layers Fabricated by Pulsed Laser Deposition for Large-Area Solid Oxide Fuel Cells

Abstract

Diffusion barrier layers are typically introduced in solid oxide fuel cells (SOFCs) to avoid reaction between state-of-the-art cathode and electrolyte materials, La1–x Sr x Co1–y Fe y O3‑δ and yttria-stabilized zirconia (YSZ), respectively. However, commonly used layers of gadolinia-doped ceria (CGO) introduce overpotentials that significantly reduce the cell performance. This performance decrease is mainly due to the low density achievable with traditional deposition techniques, such as screen printing, at acceptable fabrication temperatures. In this work, perfectly dense and reproducible barrier layers for state-of-the-art cells (∼80 cm2) were implemented, for the first time, using large-area pulsed laser deposition (LA-PLD). In order to minimize cation interdiffusion, the low-temperature deposited barrier layers were thermally stabilized in the range between 1100 and 1400 °C. Significant enhanced performance is reported for cells stabilized at 1150 °C showing excellent power densities of 1.25 W·cm–2 at 0.7 V and at a operation temperature of 750 °C. Improved cells were finally included in a stack and operated in realistic conditions for 4500 h revealing low degradation rates (0.5%/1000 h) comparable to reference cells. This approach opens new perspectives in manufacturing highly reproducible and stable barrier layers for a new generation of SOFCs.

Solid Oxide Cell Electrode Nanocomposites Fabricated by Inkjet Printing Infiltration of Ceria Scaffolds

“…The four electrodes present good attachment to the CGO barrier layer. Despite the good results of PLD barrier layers proposed by Morales et al [15], the sprayed CGO barrier layers presented in this work show lower densification upon sintering. A certain level of porosity is typical for the current SoA deposition techniques (i.e., spray coating and screen printing) [14].…”

“…One of the most important is the formation of insulating secondary phases between SoA strontium-rich perovskites and zirconia-based electrolytes (i.e., La 2 Zr 2 O 7 and SrZrO 3 ) [11][12][13]. To improve compatibility, barrier layers of ceria are commonly introduced between the electrolyte and the oxygen electrode [14,15]. Barrier layers demonstrate the ability to grant great stability at the electrolyte-electrode interface during high-temperature fabrication and operation [14].…”

Mechanism of SrZrO3Formation at GDC/YSZ Interface of SOFC Cathode

“…After post annealing at ∼1300 • C, Zr diffused outward and SrZrO 3 was formed at the surface. [21][22] The crystallographic relationship between the SrZrO 3 grains and the neighboring GDC grains was investigated at the GDC sintering condition of 1300 • C and 4 h (condition III), because under these conditions, enough SrZrO 3 was formed to identify crystal structure by electron diffraction or high-resolution electron microscopy. Figure 4 shows the electron diffraction patterns from the SrZrO 3 grains and the neighboring GDC grains, observed without tilting the sample, and the zone axis of each grain was analyzed.…”

3D printing the next generation of enhanced solid oxide fuel and electrolysis cells

“…[6][7][8] Beyond these well-known materials, other compounds such as scandiastabilized zirconia (SSZ) or La x Sr 1Àx Co y Fe 1Ày O 3Àd (LSCF) are currently employed by the industry as electrolytes or oxygen electrodes, respectively, to increase the performance of the cells at lower operation temperatures (T < 800 C). 9,10 However, stability problems of SSZ under high current densities in SOEC mode 11 and the need of diffusion barrier layers between YSZ and LSCF 12,13 still make the conventional LSM-YSZ/YSZ/Ni-YSZ combination a competitive cell, even operating at elevated temperatures (T > 800 C).…”