Yttria-stabilized zirconia (YSZ) thin films were deposited by reactive magnetron sputtering in an industrial scale setup on silicon wafers as well as commercial NiO-YSZ fuel cell anodes. The texture, morphology, and composition of the deposited films were investigated as a function of deposition parameters. Homogeneous coatings could be deposited over large areas within the coating zone, which is important for industrial applications. The use of substrate bias during film growth was identified as a key parameter to promote less columnar coatings and made it possible to tailor the texture of films deposited on Si. Bias voltages less than= - 40V resulted in highly less than 200 greater than textured YSZ films, intermediate bias voltages of - 50 V to - 70 V in less than 220 greater than textured films and high bias voltages (greater than= - 90 V) in a mixed orientation. In contrast, films grown on NiO-YSZ were seen to be randomly orientated when deposited at substrate bias voltages less than= - 30 V. When bias was further increased the film took over the orientation of underlying substrate due to substrate template effects.

Metal-supported solid oxide fuel cells are believed to have commercial advantages compared to conventional anode (Ni-YSZ) supported cells, with the metal-supported cells having lower material costs, increased tolerance to mechanical and thermal stresses, and lower operational temperatures. The implementation of a metallic support has been challenged by the need to revise the cell fabrication route, as well as electrode microstructures and material choices, to compete with the energy output and stability of full ceramic cells. less thanbrgreater than less thanbrgreater thanThe metal-supported SOFC design developed at Riso DTU has been improved, and an electrochemical performance beyond the state-of-the-art anode-supported SOFC is demonstrated possible, by introducing a CGO barrier layer in combination with Sr-doped lanthanum cobalt oxide (LSC) cathode. Area specific resistances (ASR) down to 0.27 Omega cm(2), corresponding to a maximum power density of 1.14 W cm(-2) at 650 degrees C and 0.6 V. were obtained on cells with barrier layers fabricated by magnetron sputtering. The performance is dependent on the density of the barrier layer, indicating Sr(2+) diffusion is occurring at the intermediate SOFC temperatures. The optimized design further demonstrate improved durability with steady degradation rates of 0.9% kh(-1) in cell voltage for up to 3000 h galvanostatic testing at 650 degrees C and 0.25 A cm(-2).

Strontium (Sr) diffusion in magnetron sputtered gadolinia-doped ceria (CGO) thin films is investigated. For this purpose, a model system consisting of a screen printed (La,Sr)(Co,Fe)O_3−δ (LSCF) layer, and thin films of CGO and yttria-stabilized zirconia (YSZ) is prepared to simulate a solid oxide fuel cell. This setup allows observation of Sr diffusion by observing SrZrO3 formation using X-ray diffraction while annealing. Subsequent electron microscopy confirms the results. This approach presents a simple method for assessing the quality of CGO barriers without the need for a complete fuel cell test setup. CGO films with thicknesses ranging from 250 nm to 1.2 μm are tested at temperatures from 850 °C to 950 °C which yields an in-depth understanding of Sr diffusion through CGO thin films that may be of high scientific and technical interest for implementation of novel fuel cell materials. Sr is found to diffuse along column/grain boundaries in the CGO films but by modifying the film thickness and microstructure the breaking temperature of the barrier can be increased.