Fuel cells provide direct conversion of chemical energy into electrical energy by means of electrochemical reactions. Because of this direct electrochemical conversion of energy, fuel cells offer efficient, environmentally desirable energy sources, and are targeted as one of the solutions for future energy needs. A fuel cell basically requires an anode and a cathode separated by an ion-conducting electrolyte. Different classes of fuel cells operate over a wide range of temperature depending on the electrolyte used. Solid oxide fuel cells (SOFCs) have generated interest due to their high expected energy efficiency as reported by the Department of Energy. There is tremendous interest in lowering the temperature requirements of SOFCs to at least an intermediate temperature range of 600 800 ºC while still maintaining high efficiency. These intermediate temperature (IT) SOFCs require new materials and alternate structures to achieve high electrochemical efficiency at lower temperatures. How to achieve this is the problem.
Investigators Christos Takoudis, Gregory Jursich, Robert Klie, and Alan Zdunek from the University of Illinois at Chicago, along with Jeffrey Miller from Argonne National Laboratories in Illinois believe their team and the procedures they will employ are exactly what are required to make progress on a new class of IT SOFCs. One key to achieve lower temperature operability is to engineer the SOFCs with smaller thickness for each of the anode, cathode and electrolyte layers and with precise control over the chemical compositions of the layers. Using a unique atomic layer deposition/chemical vapor deposition (ALD/CVD) hybrid reactor currently installed at the Advanced Photon Source at Argonne Labs to create complex metal oxides with thicknesses varying from near bulk-like micron layers to atomic-like nanometer layers, the PIs will develop and control the thermal and electrochemical properties of the IT-SOFCs to achieve successful reduced temperature operability. One must know what has been chemically crafted, so the PIs will use X-ray absorption and X-ray diffraction during ALD/CVD deposition, reaction and thermal transformation conditions to better understand and control the synthesis process of the final micro-nano material structures. This unique experimental set-up will allow hitherto unavailable understanding of electrochemical, catalytic and thermal property trends from the macroscopic to microscopic chemistries. In addition, the equipment will allow the PIs to fabricate all three components within the same reactor as one deposition process, resulting in atomically well-defined interfacial regions and evaluation of the three components as an integral system.
The concept for this new fuel cell program is straightforward: make thin layers of controlled chemical composition in one reactor so the interfaces are also controlled, and the chances of creating a viable IT SOFC are vastly improved. Use of the correct analytical equipment to know what has been made is key to success. The PIs intend to couple this technical program with the existing modes of enlisting of graduate students, including those from under-represented groups, already in place at UIC. Potential outreach educational programs are planned as well to spread the science to undergraduates and high school students.
