ESL Electro-Science Doubles Power Density for Solid Oxide Fuel Cells

7 November 2005

ESL Electro-Science has been able to more than double the power density achieved with conventional solid oxide fuel cell (SOFC) electrolytes by using scandia-stabilized zirconia (ScSZ).

The company is announcing the commercial availability of ScSZ in both tape form and as a fired substrate—a major step forward for developers of cost-efficient SOFCs.

The new ScSZ ceramic is made by adding scandia (Sc₂O₃) to zirconium oxide (ZrO₂) to optimize the crystal structure. The raw materials are first tape cast into a flexible sheet, then sintered at high temperature.

The new ScSZ exhibits improved ionic conductivity and mechanical strength while its coefficient of thermal expansion is about the same as yttria stabilized zirconia (YSZ). The use of ScSZ thus helps increase power-generating characteristics of the devices, while decreasing size and cost.

Although SOFCs are currently more likely to be used for stationary, power-generation applications than for mobile due to their high operating temperatures (more than 1,300º F, or about 700º C), recent research at Stanford has pointed toward a possible reduction of that operating temperature while maintaining power density to around 250º–400º C by making the YSZ electrolyte membrane as thin as 50 nm (nanometers). (Earlier post.)

ESL is working with thin zirconia tapes in the realm of 10–20µm (micrometers)—or 10,000–20,000 nanometers.

Resources:

• Manufacturability of Very Thin Zirconia Tapes In An ISO 9001 Environment