Metal ion diffusion is an effective strategy to suppress the internal electronic short circuit in ceria-based solid oxide fuel cells (SOFCs). This could be achieved by fabricating an electron-blocking layer between the barium-containing anode and ceria-based electrolyte. In this paper, a 0.6NiO-0.4BaZr(0.1)Ce(0.7)Y(0.2)O(3-) (NiO-BZCY) anode-supported cell based on Gd0.1Ce0.9O2- (GDC) electrolyte was employed to evaluate the internal metal ion diffusion behavior. The high open circuit voltages of about 1V obtained at 550-700 degrees C can be attributed to insitu formation of an electron-blocking interlayer between NiO-BZCY and GDC. Microstructural analyses of the interlayer grains obtained by traditional solid-state reaction were carried out. Phase identification demonstrated that the electron-blocking interlayer had a perovskite structure. SEM and TEM analyses indicated formation of a new compound in the interlayer, of which the composition was determined as Zr, Y, and Ni co-doped BaCe0.9Gd0.1O3 with orthorhombic structure.