Fuel Cells Join the Micro Revolution

Thin-film technology can apply to innovations beyond solar cells. Research at the Center for Superconductivity and Advanced Materials (TcSAM) at the University of Houston (UH) in Texas is ensuring that advances in solid oxide fuel cell (SOFC) technology will benefit from thin-film applications.

Houston, Texas — August 3, 2004 [SolarAccess.com] “By using materials science concepts developed in our superconductivity research, and materials processing concepts in our semiconductor research, we are able to reduce operating temperatures, eliminate steps and use less expensive materials that will potentially revolutionize from where we derive electrical energy,” said Alex Ignatiev, who is the director of TcSAM and a university professor of physics, chemistry, and electrical and computer engineering. Thin-film SOFCs have power potential for government use in matters of defense and space travel, and for the consumer market for use in computers and electricity sources. Cells in development at TcSam are one micron thick, according to Ignatiev, the equivalent of about one-hundredth of a human hair. Four fully developed cells that are equivalent in size to four sugar cubes could produce 80 W of energy, enough power to operate a laptop computer. By the same token, Ignatiev said, cells equaling the size of two soda cans could produce more than five kW. Inherent to the more efficient design of thin-film fuel cells is the fact that they can operate at a much lower temperature than other solid oxide fuel cells. SOFCs, in general, operate between 900 to 1,000 degrees Celsius, and require exotic structural materials, such as platinum, and significant thermal insulation. A thin-film SOFC has an operating temperature between 450 to 500 degrees Celsius. This lower operating temperature is a result of the decreased thickness of the electrolyte-working region in thin-film, and negates the need for exotic structural materials and extensive insulation. The lower temperature also eliminates the need for reformers for the fuel cell. One thin-film SOFC would have an output of 0.8 to 0.9 Volts, according to the TcSAM research. A stack of 100 to 120 of these fuel cells could generate about 100 volts, and when connected to a homeowner’s natural gas line could provide the needed electrical energy to run the household at an efficiency of approximately 65 percent. Ignatiev said he believes stand-alone household fuel cell units could form the basis for a new distributed power system where homes would feed energy back into the area power grid. And like all fuel cells, these could run off hydrogen as well which can be created from renewable energy technologies like solar and wind. Ignatiev said he would like to see the TcSAM, which is a NASA Research Partnership Center, SOFC research used for government applications, such as gear for soldiers in the field and compact power sources on shuttle missions. However, preliminary data on the research has to pass muster with the Department of Defense before the government will use the technology. Ignatiev anticipates that what he and his colleagues have been developing in the TcSAM laboratories will advance to the testing phase within the next six months. The collaborative test bed for this thin-film SOFC testing is the Houston Advanced Research Center’s Center for Fuel Cell Research and Applications.