OPTIMIZATION AND MODELING OF FUEL-CELL ELECTRODES WITH EMPHASIS UPON CATALYST UTILIZATION AGING PHENOMENA AND AGING PREVENTION

Fuel cell electrodes demand specifically designed electrode structures and electrocatalyst morphologies. Low-temperature cell electrodes are composed of highly dispersed carbon, on the inner surface of which th e catalyst, i.e. platinum or platinum alloys, is distributed as nanocr ystals. Pt catalyst particles are most effectively stabilized by using Pt alloys. These catalysts together with dispersed PTFE are worked in electrodes into submicron scale agglomerates establishing micron pore s between the agglomerates, kept open for fast diffusive gas transport . Agglomerates and the hydrophilic part of the pores are flooded by th e electrolyte. In high-temperature cells typical structural features a re established on a micron scale. Nickel sinter anodes in MCFCs and SO FCs are most effectively stabilized by dispersion hardening. Modelling of the different electrode structures allows us to understand mass tr ansfer and conductivity limitations of fuel cells and helps to improve catalyst utilization and cell performance.