A theoretical model for the electrical conductivity of core–shell nano-composite electrode of SOFC

A nano-composite electrode with a core–shell structure is superior to the traditional design in terms of performance and durability. But the theory for the electrical conductivities influenced by the core–shell structure is lacking, hindering its theoretical analysis and modeling activity. Combining the physical picture of the core–shell structure and the percolation based conductivity theory, explicit expressions for the ionic and electronic conductivities of the composite electrode are derived. The new model reveals the relationship between the ionic and electronic conductivities of the electrode and its compositions. Numerical results on the percolating threshold, electronic conductivities and I–V curves for the Ni-coated YSZ anode are shown to be in good agreement with the experimental data. The proposed conductivity model may be used for in-depth analysis and design optimization of the core–shell electrode.