Electro-catalyst Infiltration of Engineered Solid Oxide Fuel Cell Electrodes

PI: Stephen Sofie, Montana State University

Solid oxide fuel cell (SOFC) systems are being considered at NASA for aircraft and other aerospace applications.  While DOE targets for transportation focus predominantly on cost with power densities of less than 0.1 kW/kg, aeronautic and space applications require an order of magnitude increase in specific power density to achieve 1.0 kW/kg, which is a minimum requirement that has been set forth by NASA.  Recently NASA has developed a new SOFC concept to achieve these high power densities in a robust, low weight/volume, cell design that has the potential for higher temperature operation, greater than 900C, and minimized degradation.  To overcome deficiencies with traditional electrode technologies in regards to gas diffusion limitations and electrode degradation, NASA has also developed a new processing technique in which pore structures can be engineered for optimum performance and thus infiltrated at low temperatures with active electro-catalysts.  Infiltrated electro-catalysts are a relatively new technology approach that minimizes chemical/reaction and degradation of traditional sintering processes while allowing for a much broader range of materials selection.  While chemical infiltration is not an entirely new concept, the NASA engineered pore structures have unique morphologies and hence requirements that require a specialized approach for infiltration.

This research program will study the effects of pore morphologies prepared with traditional infiltration routes utilizing substrates fabricated by the NASA engineered pore technology.  Surface modifications will be employed to improve coating application/interconnectivity, and modifications to the traditional infiltration routes will be developed to not only minimize the necessity of multiple infiltration processes, but also to address degradation that can arise from depositing sub-micron features that are prone to ripening during heat treatment.  This preliminary research will culminate with the fabrication and characterization of infiltrated SOFC engineered electrodes in the testing of full operational SOFC's.