A Thin Film, Anode-Supported Solid Oxide Fuel Cell Based on High Temperature Proton Conducting Membrane for Operation at 400 to 700 C

Proton-conducting solid oxide fuel cells (SOFC) offer advantages over SOFCs based on oxygen ion conductors. Proton-conducting SOFCs are comprised of thin electrolyte films, supported on anodes without the use of noble metals, and are capable of operating on hydrogen between 400 and 700oC. Water vapor (reaction product) is formed at the cathode, thus avoiding the fuel dilution that is typical of SOFCs based on oxygen ion conductors To make this technology a reality, high-temperature proton conductors, which are stable over a wide range of temperatures (at least up to 700oC) and exhibit a high affinity for H2O in typical SOFC atmospheres, must be developed. This project will develop these conductors and evaluate their electrochemical performance in thin-film anode-supported cells, which will be fabricated as part of the project. In Phase I, stable perovskite oxides will be doped with appropriate elements to increase both the oxygen vacancy concentration and the affinity for H2O. Samples will be prepared and their transport properties in fuel cell atmospheres will be measured. Button cells will be fabricated and electrochemically tested, and their performance will be analyzed using a parametric equation that describes fuel cell performance. Commercial Applications and Other Benefits as described by the awardee: Proton conducting SOFCs should have commercial applications in automotive transportation; uninterrupted power sources for computers, the information and semiconductor industries, andfor residential use; for distributed power; and for hydrogen generation, when used in the reversible mode as an electrolyzer. Compared to PEM fuel cells, proton-conducting SOFCs would offer more economy, due to the use of non-noble-metal, low-cost catalysts; and higher operating temperatures, which allow for simplified reformer design and greater efficiency.