Vergleich von Elektrolyseur und Brennstoffzelle mit polymerem Festelektrolyt

Energy conversion in electrochemical cells with ion exchange membranes as electrolyte shows some interesting advantages. Membrane systems are especially suitable for small units, because of their high efficiency compared to systems with liquid electrolyte. The operating principle of electrochemical cells with polymer electrolyte is described. The requirements which have to be fulfilled by membranes for use in waterelectrolysis and H2/O2 fuel cells are explained and the properties of some commercial membranes are discussed. Various methods for pretreatment of the membranes (swelling, grinding) are investigated. A survey of methods of coasting the membrane with the catalyst is reviewed from the literature. The chemical precipitation of the catalyst onto the membrane is in detail illustrated. The electrochemical kinetics of electrodes on polymer electrolytes are presented. Current-voltage-curves of waterelectrolysis and H2/O2 fuel cell operation as well as Tafel diagrams of oxygen evoluti on and - reduction of platinum of Nation R117 are shown. First measurements concerning waterelectrolysis in alkaline medium which means the use of an anion exchange membrane and Nickel as electrode material are carried out. The remarkable improvement of the efficiency and the substitution of the noble metal catalyst are the main advantages. Membrane technology offers an attractive potential for the further development of waterelectrolysis and fuel cells.