(525f) Linking Electrode Performance with Structure Using X-Ray Tomography

Fuel cells have been extensively investigated as alternative power sources due to their high efficiency, high energy density and low emissions.  Unfortunately, broad commercialization of fuel cells has been hampered by prohibitively high costs and insufficient component durability.   The complex electrochemical, transport and degradation processes that govern the performance of catalysts/electrodes within an operating fuel cell need to be understood better, so cheaper and more robust electrodes can be manufactured.

The investigation of fuel cell electrode degradation is often done by studying the structural and compositional changes in catalyst layers. However, the structural properties of the gas diffusion layer (GDL) also play an important role. Its structure plays a key role (i) in transport of the reactant gas from flow channels to catalyst layer effectively, (ii) in draining out liquid water from catalyst layer to flow channels, and (iii) in conducting electrons with low resistance.  Therefore, a better understanding on the relationship between the electrochemical events in the catalyst layer and the transport phenomena in the GDL is needed to improve the fuel cell performance and durability.  To this end, we have employed a microfluidic platform to investigate electrochemical performance characteristics.  Also, we have used micro-tomographic imaging (MicroCT) to characterize the 3-D architecture and organization of the whole electrode, information that cannot be accomplished by typical surface imaging method such as scanning electron microscopy (SEM)

In this presentation, we will demonstrate the development of structure-activity relationships for electrodes within operating fuel cells.  Specifically, we will demonstrate how MicroCT allows for qualitative and quantitative analysis of the whole fuel cell electrode, for example, as a function of electrode preparation methods.