Dyeing polyvinyl alcohol membrane with low-temperature reactive dye X-2R as a new type of proton-exchange membrane for fuel cells

• Membranes dyed by Reactive dyes were first carried out to be applied in the field of fuel cells.
• PVA/X-2R proton-exchange membranes were prepared.
• The membrane displayed conductivity of 0.0519 S cm− 1 at room temperature.
• The membranes also showed good oxidative stability.
• Performance of MEA showed a peak power density of 48.9 mW cm− 2.

In this work, a new type of proton-exchange membranes constructed by poly(vinyl alcohol) and X-type reactive dyes (X-2R) had been successfully prepared and comprehensively investigated in depth. FT-IR and SEM were used for chemical and structural characterization of these membranes. The membranes' H+ conductivity and water uptake were studied using AC impedance technique and the method of weighing, respectively. The effects of different thicknesses of the membranes were emphatically studied. Considering all properties, the optimal thickness of the PVA/X-2R membrane was 45 μm, and the resulting membrane exhibited high proton conductivity 0.0519 S cm− 1 at room temperature with the water uptake reaching 1.57 g g− 1, which afforded a power density of 48.9 mW cm− 2 at 127.4 mA cm− 2 and open-circuit voltage (OCV) of 893.1 mV. The PVA/X-2R membrane remained about 75.2 wt% of the originals up to 30 h in Fenton's reagent (3%H2O2(V/V), 2 ppm FeSO4), which showed the high oxidative stability. Thermal analysis also showed that the PVA/X-2R membranes exhibited the significant improvement of thermal stability.