| dc.description.abstract | Typically, the proton conductivity of a polymer electrolyte membrane (PEM) decreases when the relative humidity (RH) of the environment decreases or the temperature increases. This drawback significantly complicates the design of PEM fuel cells.
Crosslinkable poly(phenylene sulfonic acid) (cPPSA) copolymer could overcome the above limitation due to its superior proton conductivity even at low RH. Unfortunately, cPPSA has poor mechanical characteristics, which precludes its direct application as a fuel cell membrane material.
In the present work, three approaches to reinforce cPPSA were investigated: (i) Pore-filling of electrospun PPSU mats; (ii) Pore filling of commercial expanded PTFE films; and (iii) Blending with a 3M PFSA ionomer. The best results were obtained with cPPSA-ePTFE composite membranes, which showed excellent proton conductivity - 3-4 times greater than that of Nafion® reference in the 40-90 %RH range at 80 ℃, and a high tensile strength exceed 20 MPa at room temperature and 50 %RH.
Membrane-electrode assemblies fabricated with these membranes and commercial Pt/C-based electrodes, and tested in hydrogen fuel cell with air and oxygen, at 80 °C. Excellent power output of 1W/cm2 (PMAX) was generated in H2/Air fuel cell at 80 °C and 100 kPa backpressure, with only 15% power reduction, when RH was decreased from 100 %RH to 30 %RH. | |
