Development of Long-Term Stable and High-Performing Metal-Supported SOFCs

Abstract

Metal-supported SOFCs are believed to have high potential for commercialization due to lower material costs and higher robustness in fabrication and operation. However, the development of the cell is challenged by the metal properties during fabrication, and the necessary lower operating temperatures, while retaining both the energy output and the stability. The metal-supported SOFC design developed at Riso̸ DTU has been optimized to an ASR value of 0.62 Ωcm2 at 650 °C, and a steady degradation rate of 1.0% kh-1 demonstrated for 3000 h on a 16 cm2 active cell level. Additional improvement in the performance has been demonstrated possible with cobalt-based cathode materials in combination with a magnetron sputtered CGO cathode barrier layer. Initial ASR values down to 0.27 Ωcm2 at 650 °C and power densities up to 1.14 Wcm-2 was observed with this design on a 0.5 cm2 active cell level.

Recent developments in metal‐supported solid oxide fuel cells

“…The cell fabrication in the METSOFC program, is carried out as follows: Tape Casting is a very well‐known highly scalable technique and is implementable not only on ceramic powders but also on metallic powders. Relatively thick metallic ‘tapes’ followed by thin electrolyte (Sc‐YSZ, codoping of Y and Sc on Zironia) were co‐tape cast, followed by drying and lamination, and then cutting into the right size, allowing for shrinkage during the sintering process. Cofiring of a tape‐cast zirconia electrolyte and the powder metallic support (ferritic steel Fe–Cr powder 22% Cr‐based stainless steel alloy)—cosintering processes are proprietary, although the authors mention that it was carried out above 1000°C in a hydrogen/argon atmosphere. Infiltration of the electrocatalyst precursor solutions followed by calcination at 350°C for 2 h, resulted in a coating of nanoparticles on the porous metallic surface—10 wt% Ni on Ce 0.8 Gd 0.2 O 1.9 (GDC20) …”

“…In summary, MSCs developed, by the Riso/DTU/Topsoe, were scaled up in size from 4 to 144 cm 2 , which was incorporated into a 25‐cell stack, which has been shown to work effectively. The authors report ASR performance of the button cells to be less than 0.3 Ω·cm 2 measured at 650°C.…”

“…Most developers continue to use Ferritic steels for IC applications . As the IC development is ‘across the board’ extending to all kinds of cells, developments in ICs and coatings, have not been discussed very much in this review.…”

“…In summary, MSCs developed, by the Riso/ DTU/Topsoe, [15][16][17][18] were scaled up in size from 4 to 144 cm 2 , which was incorporated into a 25-cell stack, which has been shown to work effectively. The authors report ASR performance of the button cells to be less than 0.3 ΩÁcm 2 measured at 650 C. However, tests with simulated diesel reformate gas (containing 0.65 ppm sulfur) resulted in high degradation rates, which is a very different issue, altogether.…”

Recent Progress in Development and Manufacturing of SOFC at Topsoe Fuel Cell A/S and Riso̸ DTU

“…Cells with different anodes (6) and different types of CGO barrier layers between the cathode and the electrolyte have been investigated (7). For the LSC cathode chosen, it appeared that the ASR of the cells correlated to the quality of the barrier layer.…”