CAMP Professors Carryout Fuel Cell Research continued from page1

Professor Dipankar Roy

Professor Roy's group is characterizing advanced materials for fuel cells using electrochemical impedance spectroscopy (EIS). EIS can be combined with various D.C. electrochemical techniques for quantitative investigation of novel electrode materials for proton exchange membrane and solid oxide fuel cells (PEMFCs and SOFCs, respectively). A wide range of studies based on these combined electrochemical methods is currently underway in Professor Roy's laboratory at Clarkson University.

For PEMFCs, cathode impedance is an important factor, because the oxygen reaction generally is rate limiting in such cells. Anode performance (especially its tolerance against CO poisoning) can also be studied using EIS in the anode half-cell configuration. EIS simultaneously records the signature time constants of cell operation (mass transport/ reaction at the anode, proton conduction through the membrane, charge transfer at three-phase boundaries of the cathode, and mass transport of products). Furthermore, at high current densities, the ohmic loss in PEMFCs often becomes an important governing factor for cell performance. This is caused by electrolyte resistance as well as by other cell components, and EIS is an effective probe of these different types of ohmic losses. Professor Roy's research interest in PEMFCs focuses primarily on EIS characterization of cathode reactions, along with selected studies of anode properties and ohmic effects.

For SOFCs, EIS can identify both the sources of polarization loss and the effects of material composition on electrode performance. EIS is sensitive to electrical homogeneity of electrode and electrolyte microstructures, and hence can be used as a simple testing method in the material design stage, prior to incorporation of new materials in SOFCs. Also EIS is a standard method for studying cathode reactions in SOFCs. Open circuit voltages of SOFCs sometimes depend on the history of electrode pretreatment and activation. EIS measurements performed at different intervals, before and after polarization, provide various mechanistic details of this effect. In addition, EIS is a relatively straightforward method for identifying activation and diffusion controlled processes. Because activated catalytic reactions are strongly governed by the chemical makeup of reaction sites, identification of the rate limiting processes through EIS facilitates the task of designing electrode and electrolyte materials for SOFCs. Professor Roy's research spans over these diverse utilities of EIS in the investigation and development of novel materials for SOFCs. More information about Professor Roy's research can be found at: http://www.clarkson.edu/~samoy/

Professor Dan Goia

For more than five years, Professor Goia has enjoyed continuous support from Umicore (Hanau, Germany), a world leader in the development and manufacturing of precious metal catalysts, in developing precipitation processes to manufacture high performance catalysts for PEM fuel cells and other applications. To date, the work has resulted in several technologies for the preparation of Pt and Pt alloy nanoparticles supported on metallic and carbonaceous conductive supports, which have been captured in four worldwide patents. More recently, the research conducted by Professor Goia's group has been included in a collaborative effort between Umicore and GM (Rochester, NY).

Professors Ian Suni and Don Rasmussen

Professors Ian Suni and Don Rasmussen are working with NanoDynamics, Inc. to develop improved methods for coating solid oxide fuel cell (SOFC) interconnects. SOFCs are a clean and efficient energy source that can burn a variety of fuels, including hydrogen and several different hydrocarbons. To obtain a higher voltage output, interconnects connect a series of individual cells into a solid oxide fuel cell stack. Since SOFCs operate at an elevated temperature, interconnect coatings may be needed to prevent unwanted reaction and transport.