Thermal treatment and properties of Ni-SDC cathode for high temperature fuel cells

The composite Ni-SDC cathode is a key element in the formulation of the hybrid MCFC/SOFC system. It must encompass electrical and ionic conductivity, high catalytic activity to allow for the reduction of oxygen and the oxidation of carbon dioxide and provide high permeability for gaseous reactants. This requires not only a specific chemical composition but also the microstructure has to be designed and specifically manufactured. These studies present the thermal treatment process and resultant properties of Ni-SDC cathodes with various SDC volume fractions. A new procedure for producing the Ni-SDC cathode was optimized based on the reference sintering process for pure Ni, modifying the temperature profile as well as the atmospheric gas composition (air, nitrogen, nitrogen + hydrogen mixture) and the sintering temperature (800°C, 900°C, 1000°C). This was done using thermogravimetric analysis (TGA) and electron microscopy (SEM). The research results show that the addition of SDC, with a specific atmospheric formulation, facilitates the organic phase decomposition. It has been observed that an increase in sintering temperature enhances mechanical strength and improves electrical conductivity.