Composite Ceria Eletrolytes for Solid Oxide Fuel Cells

40826 November 13, 1996 NexTech Materials, Ltd. Although oxygen-conducting ceramics are used as electrolytes in solid oxide fuel cells (SOFCs), their requirements for high temperature operation cause material compatibility problems. The primary obstacles are: high operating temperatures of the current materials, low volumetric efficiency, and poor materials compatibility with the operating environment. This project will develop a new composite nanostructured ceria electrolyte with higher conductivity at lower operating temperatures. The approach involves a unique synthesis method for making a novel mixture of oxide ceramic precursors. The mixture has been selected to give a composite solid electrolyte which: (1) can be operated at lower temperatures, (2) will have higher ionic conductivity resulting in improved volumetric efficiency, and (3) will eliminate electrical conductivity in oxygen depleted atmospheres common to SOFCs. Phase I will demonstrate the materials synthesis and ceramic fabrication technologies required for exploitation of the concept. Properties of the novel ceramic electrolytes will be evaluated to determine performance versus theoretical expectations. In Phase II, the materials synthesis and fabrication technologies will be optimized and scaled up for demonstration in prototype SOFC systems. Anticipated Results/Potential Commercial Applications as described by the awardee: This project should result in composite ceria electrolytes with superior oxygen transport properties compared to existing materials. The new materials should replace zirconia-based electrolytes, allowing for lower operating temperature and smaller overall system size. Large-scale applications include power generation for residential, industrial, and transportation uses. Other applications for the technology include oxygen generation for home health care, industrial, and military uses.