Poly(ether ketone) composite membranes by electrospinning for fuel cell applications

Abstract

This work is dedicated to preparation of the composite membranes to control the water absorption and dimensional stability of a highly sulfonated poly(ether ketone) matrix. To achieve this goal, the non-sulfonated poly(ether ketone) fibers are prepared by electrospinning process and then fibers are impregnated by highly sulfonated poly(ether ketone). Both highly sulfonated and non-sulfonated polymers are synthesized by condensation polymerization reaction and are characterized by spectroscopic methods. The water absorption measurements indicate that introducing 20 and 30 wt% of non-sulfonated fibers lead to the water absorption of 31 and 25% respectively, in comparison to water absorption of highly sulfonated matrix that is 54%. The presence of fibers also improves the mechanical strength of membranes. Tensile strength reaches from 27 to 81 MPa by addition of 30 wt% electrospun fibers. Moreover, in H2/O2 fuel cell performance test, the composite membranes show current density in the range of 700–1090 mA cm−1 at different cell temperatures and backpressure amounts. Also proton conductivity of the samples is examined by electrochemical impedance spectroscopy and the values are between 0.05 and 0.16 S cm−1. Morphology of the fibers and membranes is studied by scanning electron microscopy as well.