UiO-66-NH2 modified SPEEK proton exchange membranes with enhanced proton selectivity for electrochemical hydrogen compression

Hydrogen energy is a promising carrier for decarbonizing energy systems, but its low volumetric energy density requires efficient storage and transportation. Electrochemical hydrogen compression provides quiet and energy-efficient hydrogen compression and purification, relying on proton exchange membranes with high conductivity and mechanical robustness. Herein, sulfonated poly(ether ether ketone) (SPEEK) with a sulfonation degree of 63.5% was prepared by post-sulfonation, and UiO-66-NH 2 (UN) was incorporated to fabricate SPEEK/UN composite membranes. The amino groups, Zr-OH sites, and confined water in UN provide proton-relay sites and regulate the interfacial proton-transport environment. The optimized SPEEK/UN-0.75 membrane exhibited a conductivity of 231.4 mS cm −1 and tensile strength of 57.6 MPa at 60 °C and 100% RH. Its proton selectivity increased from 4.55 to 13.89, and an outlet pressure of 2.37 MPa was achieved, outperforming SPEEK and Nafion 115. This membrane design provides a promising strategy for developing proton exchange membranes for electrochemical hydrogen compression.