Novel reduction-resistant Ba(Ce,Zr)1−xGdxO3−δ electron-blocking layer for Gd0.1Ce0.9O2−δ electrolyte in IT-SOFCs

Partial internal electronic short circuit continues to be a main problem for ceria-based oxide-ion conductors. A novel composite anode composed of BaZr0.45Ce0.45Gd0.1O3−δ and nickel (Ni–BZCG) is proposed to avoid partial reduction from Ce4+ to Ce3+ in Gd0.1Ce0.9O2−δ (GDC) electrolyte by forming a functional electron-blocking interlayer in situ at Ni–BZCG|GDC interface. Open circuit voltages (OCVs) above 1.0 V at 650 °C can be achieved for cells with Ba-containing anodes, which are much higher than the value obtained with Ni–GDC anode (lower than 0.8 V) under the same conditions. The enhanced OCVs are attributed to the formation of a new electron-blocking layer with GDC@Ba(Ce,Zr)1−xGdxO3−δ core/shell structure. The interrelations between the structural interlayer and the OCVs for improved cells are also studied. Furthermore, based on the microstructure of the new structured interlayers in the fuel cells, the high polarization resistance can be mainly attributed to the insulative BaNiO3−δ phase reducing reaction zone at anode.