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O: Fachverband Oberflächenphysik
O 64: Focussed Session: Solid-liquid Interfaces I
O 64.3: Topical Talk
Donnerstag, 14. März 2013, 11:15–11:45, H31
Electrochemical energy conversion - interesting challenges for Surface Scientists — •Harry E. Hoster — Technische Universität München, TUM CREATE, 10-02 CREATE Tower, Singapore 138602
I will highlight important contributions by Surface Science towards a better understanding of options and limits of improving electrodes for low-temperature fuel cells and metal-air batteries. Structure-property relationships for bimetallic electrocatalysts in fuel cells can be elegantly observed and quantified in electrochemical studies involving particularly well-defined bimetallic surfaces. Preparation and imaging methods in vacuum provide optimum control of structure and composition of such model electrodes. For typical fuel cell reactions like O2 reduction, H2 oxidation, or CO oxidation I will show that by this approach we can not only screen metal combinations and surface compositions for optimum performance, but also identify the roles of distinct metal surface atoms and ensembles in adsorption and reaction.
Similar to fuel cells, cathodes of metal-air batteries must be active for electrochemical oxygen reduction. The energy drawn from a metal-air cell, however, results from the formation of a solid state metal-oxide film hosted by the cathode. Using the example of a Li-O2 model cell I will illustrate how nucleation and growth of that film can give rise to serious history dependent limitations of the available energy content.
New types of batteries also mean new challenges for Surface Scientists. We have to tackle these challenges by new efforts in developing and improving experimental and theoretical methods.