LSGM-based Cells for IT-SOFC Applications

Solid Oxide Fuel Cells have still many technical problems related to its high operating temperature (800–1000 °C). The most recent studies deal with reducing the operation temperature increasing at the same time the durability of the device. The use of La_0.8Sr_0.2Ga_0.8Mg_0.2O_3-δ(LSGM) perovskite as electrolyte, could be a very promising solution for IT-SOFC operating at 600°C. In this work, LSGM bilayers constituted by a thicker porous layer (namely the anode scaffold) and a dense electrolyte were produce by co-firing using two different techniques: i) die-pressing + spin coating, ii) tape casting + lamination. In both cases the nature and amount of pore former needed to obtained an anode scaffold with a porous network suitable for the Ni impregnation process were deeply investigated.

In the die-pressing + spin coating method, supporting anodes were prepared pressing LSGM commercial powder with a proper amount of binder and a tailored mixture of pore forming agents. Onto the pre-sintered anode support, an electrolyte layer was deposited by spin coating. In the tape casting + lamination route, the starting ceramic suspensions with and without pore formers were carefully optimized to produce the anodic and electrolytic green tape respectively, while the lamination parameters, in terms of temperature, time and pressure, were adjusted to obtain defect-free bilayers. The sintering conditions were also optimized in order to achieve the best compromise in terms of density of the electrolyte and porosity of the anode scaffold.

Structural and morphological characterizations of the produced bilayers as well as the electrochemical performances of the cells in the temperature range 600-750°C will be reported. The potentialities and disadvantages of the two processing approaches will be thoroughly discussed.