Evolution of the electrochemical interface in Solid Oxide Cells
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Evolution of the electrochemical interface in Solid Oxide Cells
Fri, 16/09/2016 - 14:00 to 15:00
Location:
Speaker:
Prof. John TS Irvine
Affiliation:
University of St Andrews
Synopsis:
High operating temperatures place significant constraints on electrodes, electrolyte and interconnect materials for Solid Oxide Cells (SOC) so limiting choice to maintain several important requirements. All materials must not be reactive with adjacent components at the high operating temperature, and must have compatible thermal expansion coefficient. Interconnects and electrolytes must be impermeable to gas, show high conductivities to minimize losses (electronic and ionic respectively), and be stable in both reducing and oxidizing atmospheres. Electrodes must show high electrocatalytic activity and must be designed with an extended active surface area (Triple Phase Boundary points). Electrodes must fulfil some important requirements to ensure high and durable power output. To extend the TPB area, electrodes are fabricated as mixed ionic and electronic conductors (MIEC) porous ceramics or ceramic-metallic composites. An ideal microstructure would offer the highest triple phase boundary (TPB) length for electrochemical reactions, an optimized contact between the electrolyte and the electrode, and be dimensionally stable during operation (mechanically, chemically and thermally).
It is particularly important to note that normally the critical region determining the performance and efficiency of SOC devices is the-region of the electrode at the electrode/electrolyte interface. Typically this only extends a few microns and for best performance involves intricate structures on the nanoscale. Here we address the nature and activity of this interface and its electrochemistry, paying particular attention to new developments in controlling and modifying this interface to optimise both performance and durability.
Biography:
Professor John Irvine is Professor of Chemistry at the University of St Andrews and currently holds a Royal Society Wolfson Merit Award. His first degree is in Chemical Physics from Edinburgh University and he obtained a DPhil from the University of Ulster in Photoelectrochemistry. He performed his postdoctoral studies working with Anthony West in Aberdeen and was subsequently appointed to a BP/RSC fellowship, lectureship and senior lectureship at Aberdeen University. In 1994 he was visiting Professor at Northwestern University and then moved to the University of St Andrews as Reader and then Professor of Inorganic Chemistry in 1999.
His research interests include solid state ionics, new materials, ceramic processing, electrochemistry, fuel cell technology, hydrogen, photoelectrochemistry, electrochemical conversion and heterogeneous catalysis.
In 2005 he was elected a Fellow of the Royal Society of Edinburgh. In 2008 he received the Royal Society of Chemistry Materials Chemistry Award, the Royal Society of Edinburgh Sustainable Energy Award in 2015 and Gold Medal winner at the EFCF, Lucerne 2016. He has over 400 publications in refereed journals including Nature and Nature Materials. He has developed new concepts in fuel cells, e,g. the Hybrid Direct Carbon Fuel Cell, has a leading role the field of developing redox stable, coking tolerant oxide electrodes for SOFCs and discovered the first significant interstitial oxide ion conductor. He was Chairman of the 2010 European SOFC Forum in Lucerne and Chair of the Scientific Committee for the Faraday Discussion, York 2015. He is currently European Councillor for the International Society of Solid State Ionics and Co-director of the Energy Technology Partnership.