Nanostructured ceria based thin films (≤1 μm) As cathode/electrolyte interfaces

Gadolinium doped cerium oxide (CGO: Ce0,9Gd0,1O2−δ) films were used as an oxygen anion diffusion layer at the cathode/electrolyte interface of Solid Oxide Fuel Cells (SOFCs), between LSCF (lanthanum strontium cobalt ferrite) and YSZ (yttria-stabilized zirconia). Thin (∼100 nm) and thick (∼700 nm) mesoporous CGO layers were synthesized through a sol–gel process including organic template coupled with the dip-coating method. Structural and microstructural characterizations were performed, highlighting a well-bonded crystalline CGO nanoparticles network which delineates a 3-D inter-connected mesoporous network. Their electrical behaviors were investigated by impedance spectroscopy analysis of YSZ/mesoporous-CGO/LSCF half-cell. Anode-supported SOFCs, operating at 800 °C, with either dense or mesoporous CGO dip-coated interlayers were also fabricated [NiO-YSZ anode/YSZ/CGO/LSCF cathode]. The impact of the mesoporous CGO interlayers on SOFCs performances was investigated by galvanostatic analysis and compared to the behavior of a dense CGO interlayer. The polarization curves revealed an enhancement in the electrical performance of the cell, which is assigned to a decrease of the polarization resistance at the cathode/electrolyte interface. The integrity and connectivity of the CGO nanoparticles bonded network facilitates O2− transport across the interface.