Preparation and properties of sulfonated poly(ether ether ketone)/graphene oxide proton exchange membranes via electrospinning

The graphene oxide (GO) uniformly dispersed sulfonated poly(ether ether ketone) (SPEEK) composite membrane (SPEEK-GO-E) was successfully prepared by electrospinning. The effect of GO dispersion on proton conductivity and methanol barrier properties was investigated. SEM, TEM, and AFM characterizations confirmed that compared with the solution-cast SPEEK-GO-C membrane, electrospinning significantly improved GO dispersion and effectively suppressed GO agglomeration. Performance tests showed that the SPEEK-GO-E membrane exhibited excellent comprehensive properties: at 30℃, its proton conductivity reached 1.12×10⁻² S·cm⁻¹ (67% higher than pure SPEEK), while methanol permeability decreased to 5.16×10⁻⁸ cm²·s⁻¹ (80% reduction). Moreover, the membrane demonstrated isotropic swelling behavior with remarkably reduced water uptake and swelling ratio, indicating enhanced dimensional stability. The improved performance is attributed to the uniform GO dispersion enabled by electrospinning, where hydrophilic oxygen-containing groups on GO form strong hydrogen bonds with sulfonic acid groups in SPEEK chains. Simultaneously, the two-dimensional GO sheets construct long-range ordered proton transport channels, which enhance proton conduction while effectively blocking methanol permeation. This study provides a new approach for developing high-performance proton exchange membranes.