Anode-supported Electrolyte Film Research Articles

Fabrication of a YSZ electrolyte layer via co-pressing/co-sintering for tubular NiO-YSZ anode-supported SOFCs

• A simple and effective method to fabricated semi-cells of tubular Ni-YSZ anode-supported electrolyte film is proposed. • The method is the combination of centrifugal deposition, co-pressing and co-sintering techniques. • The YSZ films are dense with the thickness of 21.4∼27.3 μm. A simple and effective method to fabricated semi-cells of tubular NiO-YSZ anode-supported electrolyte film is proposed. This method is the combination of centrifugal deposition technique, cold isostatic co-pressing and co-sintering. The X-ray diffraction patterns showed that the presence of NiO and YSZ, and YSZ grains of electrolyte film grow preferentially on (2 2 0), (3 1 1), (2 2 2), (4 0 0). The YSZ films are dense with the thickness of 21.4∼27.3 μm. At 1400℃, the YSZ crystallite size in the electrolyte film is largest with the size of ∼4.6 μm, which confirms the crystallite growth during co-sintering. The EDX mapping at the same location of EDS further reveals the presence of O, Ni, Y and Zr in the calcined powders.

Preparation and Characterization of Anode-Supported YSZ Thin Film Electrolyte by Co-Tape Casting and Co-Sintering Process

In this study, a co-tape casting and co-sintering process has been developed to prepare yttria-stabilized zirconia (YSZ) electrolyte films supported on Ni-YSZ anode substrates in order to substantially reduce the fabrication cost of solid oxide fuel cells (SOFC). Through proper control of the process, the anode/electrolyte bilayer structures with a size of 7.8cm × 7.8cm were achieved with good flatness. Scanning electron microscopy (SEM) observation indicated that the YSZ electrolyte film was about 16 μm in thickness, highly dense, crack free and well-bonded to the anode support. The electrochemical properties of the prepared anode-supported electrolyte film was evaluated in a button cell mode incorporating a (LaSr)MnO3-YSZ composite cathode. With humidified hydrogen as the fuel and stationary air as the oxidant, the cell demonstrated an open-circuit voltage of 1.081 V and a maximum power density of 1.01 W/cm2 at 800°C. The obtained results represent the important progress in the development of anode-supported intermediate temperature SOFC with reduced fabrication cost.

Thermosetting polymer templated nanoporous sinter-active layer for low temperature solid oxidefuelcells

A facile synthesis method was developed to form a nanoporous metal oxide layer using poly(furfuryl alcohol) (PFA) as a thermosetting polymer template. A nanoporous Ce0.8Sm0.2O1.9 (SDC) layer with high sinterability was prepared on an anode-supported electrolyte film at 900 °C, and used as a sinter-active layer in cell fabrication to improve the interface between the inert electrolyte surface and the cathode layer of a solid oxide fuel cell (SOFC). The resulting saw-like interface improved the maximum powder density of the cell by 51% at 600 °C and 162% at 500 °C compared with that of the unmodified cell. The cell with the saw-like electrolyte–cathode interface exhibited lower electrode polarization resistance than those reported in the literature, and such improvement was much more significant at reduced operating temperatures (400–500 °C). Our study shows that the operating temperature of solid oxide fuel cells can be substantially lowered by simply improving the electrode–electrolyte interfaces.

Preparation and performance of nanostructured porous thin cathode for low-temperature solid oxide fuel cells by spin-coating method

To reduce the cathode–electrolyte interfacial polarization resistance of low-temperature solid oxide fuel cells (SOFCs), a nanostructured porous thin cathode consisting of Sm 0.5Sr 0.5CoO 3 (SSC) and Ce 0.8Sm 0.2O 1.9 (SDC) was fabricated on an anode-supported electrolyte film using spin-coating technique. A suspension with nanosized cathode materials, volatilizable solvents and a soluble pore former was developed. The results indicated that the cell with the nanostructured porous thin cathode sintered at 950 °C showed relatively high maximum power density of 212 mW cm −2 at 500 °C and 114 mW cm −2 at 450 °C, and low interfacial polarization resistance of 0.79 Ω cm 2 at 500 °C and 2.81 Ω cm 2 at 450 °C. Hence, the nanostructured porous thin cathode is expected to be a promising cathode for low-temperature SOFCs.

Multilayer tape-casting method for anode-supported planar SOFCs

We have developed a multilayer tape-casting and co-sintering process to fabricate a large-area, anode-supported electrolyte film, which is critical for planar-type, reduced-temperature solid oxide fuel cells (SOFCs). Nickel/yttria-stabilized zirconia (Ni/YSZ), nickel/scandia-stabilized zirconia (Ni/ScSZ) cermets, ScSZ, Ce0.8Gd0.2O1.9 (CGO), and La0.6Sr0.4Co0.2Fe0.8O3δ (LSCF)–CGO were used as materials for anode substrate, anode functional layer, electrolyte, interlayer and cathode, respectively. The powders of these functional layers were ball-milled with organic additives to form slurries, which were assembled together with the multilayer tape-casting procedure to get the green tapes. After drying, the green tape was co-sintered at 1400°C for 4 h in air to get the large-area, anode-supported electrolyte film (thickness 15 μm). For cell preparation, the LSCF–CGO composite cathode was deposited by the screen-printing method and sintered at 1100°C for 3 h. The area-specific resistance (ASR) of the obtained single cell was found to be 0.99 ωcm2 at 850°C with H2/O2 as the operating gases, and the maximum power density achieved was 0.63 W/cm2. The thickness of the (Zr,Ce)O2-based solid solution formed at the ScSZ/CGO interface during high-temperature sintering was investigated. The results illustrate that fabrication of an anode-supported electrolyte film for planar SOFCs with a CGO interlayer is possible by the multilayer tape-casting procedure, which is both cost-effective and feasible.

A study of multilayer tape casting method for anode-supported planar type solid oxide fuel cells (SOFCs)

In the present work, we have developed a multilayer tape casting and co-sintering process to fabricate large area anode-supported electrolyte film, which is critical for planar type reduced temperature solid oxide fuel cells (SOFCs). Nickel/yttria-stabilized zirconia (Ni/YSZ), nickel/scandia-stabilized zirconia (Ni/ScSZ) cermets, ScSZ, Ce 0.8Gd 0.2O 1.9 (CGO), and La 0.6Sr 0.4Co 0.2Fe 0.8O 3− δ (LSCF)–CGO were used as materials of anode substrate, anode functional layer, electrolyte, interlayer and cathode, respectively. The powders of these functional layers were ball milled with organic additives to form slurries, which were assembled together with the multilayer tape casting procedure to get the green tapes. After dryness, the green tape was co-sintered at 1400 °C for 4 h in air to get the large area anode-supported electrolyte film (thickness ∼ 15 μm). For cells preparation, LSCF–CGO composite cathode was deposited by screen-printing method and sintered at 1100 °C for 3 h. The area-specific resistance (ASR) of the obtained single cell was found to be ∼0.99 Ω cm 2 at 850 °C with H 2/O 2 as the operating gases, and the maximum power density achieved ∼0.63 W cm −2. The thickness of the (Zr,Ce)O 2-based solid solution formed at the ScSZ/CGO interface during high temperature sintering was investigated. The results illustrate that fabrication of anode-supported electrolyte film for planar SOFCs with a CGO interlayer is possible by multilayer tape casting procedure, which is both cost-effective and feasible.