Design and optimization of electrodes for fuel cells new opportunities for materials science and engineering

The main problem in exploitation of fuel cells is the achievement of general cost and performance goals, which have been more difficult to attain than anticipated few years ago. One of the reason is the complex nature of the porous electrode, a mixed conductor, where gaseous and liquid-like phases react. Here, we do not have only problems of materials selection and optimization, but also of controlling the morphology of the electrode, and predicting its durability in an aggressive environment. We need to address the problem of the dynamic behaviour and stability of a porous electrode in its working conditions in order i) to optimize the selection and processing of materials and, ii) to realistically model the relationships among morphology, dynamics, and mechanical properties. Such an integrated approach calls for close cooperation between materials scientists and engineers of different specializations: industrial chemistry, mechanics, fluido-dynamics. We will illustrate these points by providing overviews of areas where we are active: the molten carbonate fuel cell (in particular, the problem of the cathode behaviour and durability), the solid oxide fuel cells (with the issue of cationic diffusion).