Page 213 - High Temperature Solid Oxide Fuel Cells Fundamentals, Design and Applications

190 High Temperature Solid Oxide Fuel Cells: Fundamentals, Design and Applications

major challenges: reduction of fabrication costs and reduction of material costs.
The reduction in material costs can be achieved by both the interconnection
design and the quantity of interconnect required. However, reduction in
fabrication costs will only come with improved processing and automation
[ 1,3 1,32,63].
Lanthanum chromite has provided long lifetimes, as long as 69,000 h in
Siemens Westinghouse tubular cells, at 900-1000°C. However, metallic
interconnects have not yet shown equivalent lifetime performance.
Improvements in metallic interconnect compositions and contact layers between
cells/interconnects are still issues for materials development. In particular, the
metal/ceramic interface in cells should have low corrosion, low contact
resistance and low permeability of chromium species. Recent results have shown
that optimised steels for SOFC applications are available and alkaline earth-free
and cobalt-containing perovskites are the most suitable materials for contact
layers: however, their long-term performance under fuel cell operation
conditions needs to be proven.

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