FCETs break-through technologies for Solid Oxide Fuel Cells can enable a lower cost, non-polluting, and renewable energy source which can strengthen both the U.S. economy and national security by reducing America's dependence on foreign oil.
Solid Oxide Fuel Cells (SOFCs, also called ‘ceramic fuel cells’) operate at the highest temperatures of any type of fuel cell (generally, 800° to 1000° C). Such a high operating temperature has some real advantages: ability to internally reform hydrogen from conventional fossil fuels; generation of excess heat to run associated mini-turbines; very high energy conversion efficiency; etc.
But, such high operating temperatures also require that expensive electro-conductive ceramic materials be used to collect the electricity generated by the SOFC…common metals (such as stainless steel) lose integrity at those temperatures. The high fabrication costs associated with these exotic ceramics have kept SOFCs from reaching true commercial status.
The central layer of the SOFC has traditionally been the thickest layer of the three core layers (as shown on the photo below); and, it is generally made from the ceramic, zirconia.
Unfortunately, it is through this thick central electrolyte layer that oxygen ions must be transmitted in order for the cell to operate (see diagram above). With a thick electrolyte layer, ionic conductivity slows down. With a thinner electrolyte layer, ionic conductivity is enhanced in a direct way.
Thin Electrolytes = Higher Efficiency = Lower Operating Temp. = Lower Cost
A thin film electrolyte from FCET that is about 1 micron thick (or less) is 100 to 1000 times thinner than those now being employed. This can result in ionic oxygen transport that is at least 10 times greater. With this increased ionic transport efficiency, operating temperatures can be reduced from about 800° C down to about 650° C.
Indeed with other changes (such as varying the composition of the electrolyte & its crystalline structure and new methods of applying the FCET ‘MIST’ process), it is likely that the operating temperature can be reduced even further from about 650° C down to about 575° C.
When this low operating temperature has been achieved, the use of expensive (and difficult to fabricate) electro-conductive ceramics is rendered unnecessary. They can then be replaced with inexpensive and commonly used electro-conductive materials such as stainless steel…this could reduce the costs of an SOFC from $1,000 per kilowatt down to $200 per kilowatt.
Other Applications of FCET Nano Films in SOFCs
With thin films of catalysts, it is also possible:
- to boost the activity of the anode (fuel electrode) to provide for better internal hydrogen reforming and less fouling by carbon or sulfur residues, and
- to boost the activity of the cathode (oxygen electrode) for better oxygen absorption and oxygen ion transmission to the electrolyte.
Thin films applied by the FCET ‘MIST’ process can also be expected to prevent corrosion on many of the subsidiary metallic and ceramic components of an SOFC.
FCET is working closely with top researchers and scientists from a variety of DOE-sponsored National Laboratories to bring this technology to market.