Sulfonated polysulfone ionomer membranes for fuel cells

Sulfonated polysulfone (SPSU) membranes with different sulfonation levels h ave been prepared and evaluated as proton exchange membranes in polymer ele ctrolyte fuel cells (PEFC). The membranes have been characterized by ion-ex change capacity (IEC), thermal analysis, proton conductivity and single cel l performance. The introduction of sulfonic groups in the base polymer prod uces an increase in glass transition temperature (T-g) from 190 to about 20 0-220 degreesC and a thermal decomposition of polymer at lower temperature. Proton conductivity of 4.3 x 10(-2) S . cm(-1) at 80 degreesC on a SPSU me mbrane with IEC = 1.25 meq/g was obtained. Membrane/electrodes assemblies ( MEAs) prepared with SPSU gave, in single cell tests at 80 degreesC, power d ensities of 400 and 500 mW . cm(-2) in H-2/air and H-2/O-2, respectively. ( C) 2001 Elsevier Science B.V. All rights reserved.