Comparison of atmospheric plasma sprayed anode layers for SOFCs using different feedstock

Atmospheric plasma spraying (APS) is a cost-effective way to produce solid oxide fuel cell (SOFC) components. When using APS, therefore, sinter steps can be avoided, which is essential once a metallic support is used for the SOFC. Several properties are required regarding the microstructure of an optimized anode layer. Here, gas permeability, electrochemistry, electronic conductivity, coefficient of thermal expansion, as well as thermal shock resistance have to be considered. Different types of powder feedstock were investigated to develop an atmospheric plasma sprayed anode layer: (a) NiO or Ni together with YSZ as starting materials, (b) agglomerates in which NiO and YSZ are already mixed on a submicrometer range, (c) blended NiO/YSZ powder, and (d) separate injection of the individual NiO and YSZ powders, respectively, into the plasma by two separate powder lines. The performance of APS anodes are measured in single fuel-cell tests. Anode layers sprayed by a separate injection of the individual NiO and YSZ powders into the plasma show the best results.