Enhancing the Electrochemical Performance of Metal-Supported Solid Oxide Fuel Cells

Abstract

This paper will present the electrochemical performance and durability of metal-supported solid oxide fuel cells (MS-SOFCs) developed at LBNL. The cell is comprised of a thin ceramic electrolyte and porous electrode backbones sandwiched between stainless steel metal supports. Compared to conventional all-ceramic SOFCs, MS-SOFCs offer a number of advantages due to their low-cost structural materials (e.g. stainless steel), mechanical ruggedness, excellent tolerance to redox cycling, and extremely fast start-up capability. The sensitivity to MS-SOFCs is determined by the cell architecture, catalyst, and sintering process. Performance of the MS-SOFCs is characterized by voltage-current, impedance spectroscopy measurements at 0.7 V, and durability in 100 h. The impact of cell architecture, like thickness of the electrolyte and electrode backbone, pore microstructure of the backbone, will be reported. Catalyst is ascribed to play the major on the performance of MS-SOFCs. Here, the catalysts, such as Sm0.5Sr0.5CoO3, La0.37Sr0.38Co0.2Fe0.8O3, Pr2NiO4, Pr6O11, BaZr0.4Co0.4Y0.1Yb0.1O3, et al., will be presented with the performance obtained at 700 °C, with steam content of 3 vol.%. The initial peak power density is enhanced more than 50%. The ohmic and polarization resistances are reduced to less than 0.07 and 0.30 Ω cm-2 at 0.7 V, respectively. In addition, the sintering process of catalyst is optimized to obtain the desired crystal structure. The durability of MS-SOFCs is catalyst-dependent, which makes the selection of catalyst more significant. The primary degradation modes are currently being elucidated to the Cr poisoning on catalyst, oxidation of supported metal, and catalyst coarsening.