Abstract
Proton exchange membrane fuel cells, which efficiently convert chemical energy into electrical energy via oxidation and reduction reactions, are receiving considerable attention as an alternative energy source because of their high energy efficiency and no emissions of pollutants. One of the most important technical focuses is on developing proton exchange membranes that are able to achieve a high proton conductivity, low gas permeability of the fuel and oxidant, and sufficient chemical stabilities. Recently, we have prepared polymer electrolyte membranes composed of aligned nanofibers for the first time, and revealed that the composite membranes showed a higher proton conductivity and lower gas permeability than the membrane without nanofibers. In addition, we found that the proton conductivity of a single nanofiber significantly increased when compared to that of the membrane.
