Phosphorylated Cellulose Acetate/PVA Membranes Crosslinked With Glutaraldehyde for Proton Exchange Membrane Fuel Cells

The synthesis of membranes that combine mechanical stability with high electrochemical performance and affordable production costs remains a challenge for the commercialization of proton exchange membrane (PEM) fuel cells. In this study, polyvinyl alcohol (PVA) modified cellulose acetate (CA) bipolymer membranes were prepared by adding glycerol to increase the membrane's elasticity and H 3 PO 4 as a protonating agent. The obtained membranes were treated with a specific amount of glutaraldehyde (GA) as a crosslinker to enhance the membrane's mechanical resistance. Characterization results showed that increasing the concentration of PVA and GA improved the membrane's structural integrity and mechanical strength, with a maximum tensile stress reaching 5.82 MPa. The addition of PVA up to 20 wt% significantly increased the proton conductivity and ion exchange capacity by 0.025 S cm − 1 and 0.082 meq g − 1 , respectively, at 25°C. However, increasing the GA concentration decreased electrochemical performance due to limited proton mobility within the increasingly dense membrane network. The optimized CAP‐GA membrane offers a good balance between mechanical stability and proton conductivity, making it a potential candidate for a sustainable, economical proton exchange membrane for low‐temperature fuel cell applications.