Construction of Chemically Crosslinked Sulfonated Poly(aryl ether ketone) Networks for Polymer Electrolyte Membranes

Polymer electrolyte membranes serving in proton exchange membrane fuel cells (PEMFCs) and direct methanol fuel cells (DMFCs) must possess sufficient mechanical–dimensional stability and excellent proton conducting capacity. Derived from the successful syntheses of two different sulfonated poly(aryl ether ketone)s bearing functional amine groups, two series of novel epoxy-crosslinked and silane-crosslinked sulfonated poly(aryl ether ketone) electrolyte networks are constructed for highly conductive and mechanically stable proton exchange membranes. The designed multi-component architecture, which integrates a moderate-ion-exchange-capacity sulfonated poly(aryl ether ketone) (moderate-IEC SPAEK), a high-IEC SPAEK, and a tailored crosslinker (epoxy or silane), enables a breakthrough in decoupling the traditional trade-off between conductivity and stability. The resulting membranes exhibit an outstanding combination of properties: exceptional proton conductivity exceeding 0.18 S cm−1 at 100 °C, tensile strength above 28.80 MPa, and enhanced chemical resistance, thermo-oxidative stability, and competitive direct methanol fuel cell performance. This work establishes a rational design strategy for crosslinked multi-component membranes as a promising platform for next-generation high-performance fuel cells.