ADVANCES IN THE USE OF PERFLUORINATED CATION-EXCHANGE MEMBRANES IN INTEGRATED WATER ELECTROLYSIS AND HYDROGEN OXYGEN FUEL-CELL SYSTEMS

The application of a perfluorinated cation exchange membrane (Nafion(R) 117) in electrochemical cells suitable for alternative operation as water electrolyser and hydrogen/oxygen fuel cell was investigated. Various methods used for the preparation of membrane-electrode units were applied; the performance of the units prepared with these methods in fuel cell and electrolyser modes of operation is evaluated. Inherent advantages of a direct preparation of the catalyst layer on the membrane surface by chemical deposition could be realised only in case of platinum electrodes. In case of all other electrode materials including various noble metals and their oxides (pure or in binary composition) suitable membrane-electrode units were fabricated from PTFE-bonded catalyst layers subsequently pressed onto the membrane. Experimental results obtained with respect to performance and longtime stability are reported and discussed; further lines of development are indicated.