High Dimensional Stability and Alcohol Resistance Aromatic Poly(aryl ether ketone) Polyelectrolyte Membrane Synthesis and Characterization

Crystallized sulfonated poly(arylene ether ketone) (Cr-SPAEK) materials constructed from dense sulfonated hydrophilic segments and crystalline poly(ether ketone) (PEK) hydrophobic backbone were designed. The membrane exhibited considerable proton conductivity and superb solvent resistance owing to its special phase morphology, the presence of a broad hydrophilic ion transport channel, and a crystalline hydrophobic matrix. The dense sulfonated hydrophilic segment provides excellent proton conductivity; the Cr-SPAEK-20 membrane exhibits higher proton-conducting ability than Nafion 117 in the temperature range of 20–100 °C; its proton conductivity reaches about 168 mS cm–1 at 100 °C. The crystalline PEK hydrophobic segment ensures superior solvent resistance and dimensional stability, guaranteeing the durability of the membrane in practical applications. The methanol permeability of Cr-SPAEK-20 is only one-eighth that of Nafion 117 when the test conditions are the same. The direct methanol fuel cell (DMFC), which is assembled by Cr-SPAEK-20, exhibited satisfactory open circuit voltage and maximum power density during the testing process. The Cr-SPAEK membranes have shown potential for DMFCs as polymer electrolyte materials.