Study on the fracture behavior of the planar-type solid oxide fuel cells

In this work, the commercial SUS430 ferritic stainless steel was used as the current collector to study the fracture behaviors of the planar electrolyte-supported and anode-supported solid oxide fuel cells with the size of 10 cm × 10  cm during the thermal cycle process. The anode-supported cells (ASCs) were fabricated by tape-casting, spraying, screen-printing and co-sintering. The electrolyte-supported cells (ESCs) using fully-stabilized zirconia as material were prepared by tape-casting, multilayer lamination, screen-printing and co-sintering. The output power densities at 0.7 V (P0.7V) of the anode-supported and electrolyte-supported cells could reach 0.60 W cm−2 and 0.43 W cm−2 at 850 °C, respectively. During the thermal cycle testing, the ESC sample was cracked, while the ASC sample had no obvious changes. The thermal expansion coefficient (TEC) of the different samples was studied, and the two cells were characterized by the XRD after the thermal cycle testing. In addition, the fracture behaviors of the two cells were discussed. The results indicated that the ASC sample had the good stability during the thermal cycle testing. The excellent anti-cracking performance of the ASC was attributable to two aspects. Firstly, the TEC of the anode support is more close to that of the SUS430 material; secondly, the phase transformation of zirconia from monoclinic phase to tetragonal phase induced by stress is favorable for contraction of the anode support layer during the cooling process.