Journal of Membrane Science 185 (2001) 1
Membranes in Fuel Cells Highly efficient energy production from renewable sources with practically no pollutant emission is not a visionary goal of a far future anymore. The fuel cell technology is making this vision reality. However, a significant development must be still achieved to turn the fuel cell technically and economically competitive both in stationary and mobile applications. In order to overcome the current handicaps of the fuel cell technology, several programs are being supported all around the world combining efforts of scientific institutions and industries in a “race to change the world”, as mentioned by one of the leading companies in this field. Among the different kinds of fuel cells, the “polymer electrolyte membrane fuel cell” is the choice of most of the automotive industries, basically due to its convenient operating temperature and the possibility of using air as oxidant medium. The basic principle of this technology is the production of electricity by an electrochemical reaction, which involves the oxidation of the fuel at the anode, producing protons, which are transported to the cathode to react with oxygen forming water. The membrane here plays a decisive role as electrolyte medium for proton transport and barrier to avoid the direct contact between fuel and oxygen. Although several years of research have been dedicated to improve fuel cell catalysts and optimize technical aspects such as stack design and operating conditions, on the membrane side the devel-
opments have been mainly concentrated on Nafion, which combines the requirements of high proton conductivity and chemical stability. Today, to make the fuel cell really competitive would require components with lower cost and operating conditions at which the Nafion performance may not be acceptable anymore. One aspect is the convenience of working at temperatures higher than 100◦ C to hinder catalyst poisoning by CO and simplifying the cooling of the stacks. Hydrogen, produced from gasoline, natural gas or methanol in a reformer, is the fuel of choice for most of the fuel cells operating today. Hydrogen from these sources is not completely free of CO. An alternative is the use of other fuels such as methanol to feed directly to the cell instead of hydrogen, eliminating the reformer. In this respect, Nafion has a serious disadvantage: its high methanol permeability. The development of effective and low cost membranes for fuel cells has gained fundamental importance and turned to be a challenge for the membrane community in the last years. In this special issue of the Journal of Membrane Science we document some of the recent developments, hoping to stimulate continuing efforts in this fascinating field.
0376-7388/01/$ – see front matter © 2001 Published by Elsevier Science B.V. PII: S 0 3 7 6 - 7 3 8 8 ( 0 0 ) 0 0 6 3 0 - X
K.W. Böddeker, K.-V. Peinemann, S.P. Nunes