Study on co-sintering characteristics of metal supported solid oxide fuel cells

The sintering mechanism of electrode layer and electrolyte layer was analyzed considering the whole thermal expansion of the battery and the creep of the ceramic. The evolution of the microstructure of the electrode and electrolyte layer and the distribution and change of residual stress of the metal supported solid oxide fuel cell (MS-SOFC) under different sintering temperature and grain size were expounded. The Skorohod-Olevsky Viscous Sintering (SOVS) model was established to simulate the relative density and stress distribution and evolution of different layers and different surfaces of MS-SOFC under different sintering temperatures and different grain sizes. The change of microstructure morphology of dissimilar grain size structure after sintering was revealed by high temperature sintering experiment. The results show that the relative density of electrolyte and electrode, the residual stress value of each layer and the mutation amplitude are affected by sintering temperature. When the initial grain size of each layer of fuel cell material is small, the densification rate caused by sintering is very obvious. With the gradual increase of grain size, the densification rate is relatively small, and the residual stress value and mutation amplitude of each layer of the battery are gradually reduced. Nano-yttrium oxide stabilized zirconia (YSZ) electrolyte layer is easier to sintering, and the micro-defects are reduced more than the micron YSZ electrolyte layer after sintering. After sintering of MS-SOFC, the radial stress of cathode and anode is tensile stress, and the radial stress of electrolyte is compressive stress. Axial stress and shear stress vary periodically between tensile and compressive stress. The electrode layer with micron crystals can maintain large porosity after sintering, while the electrolyte with nanocrystalline can improve the conductivity and reduce the densification sintering temperature. When the crystal size is nanometer, the residual stress value and distribution are sensitive to the sintering temperature.