TWI Industrial Member Report Summary 807/2004
A Gunner, P Jackson and C Williams
Seals are located between each adjacent component in the solid oxide fuel cell (SOFC). The sealing material must be hermetic across the temperature range, either by matching Coefficient of Thermal Expansion (CTE) to the components, or by yielding to accommodate the expansion mismatch. The material must also be chemically stable in long term contact with the electrolyte and the surrounding sealing surface materials.
Glasses and glass-ceramics are currently the state of the art method for sealing SOFCs. However, there are two major issues with the current generation of glass-ceramic seals. Matching CTE of the sealant to the component has proved difficult and the presence of silica in the glass 'poisons' the zirconia electrolyte, reducing its conductivity and hence efficiency.
- To develop novel sealing and joining materials for solid oxide fuel cells, capable of withstanding an operating temperature of 1000°C.
- To develop methods for overcoming CTE mismatch between sealants and components.
- To develop a diffusion barrier to prevent silica-bearing sealants poisoning zirconia electrolytes.