Sulfonated poly (aryl ether ketone sulfone) modified by polyoxometalates LaW₁₀ clusters for proton exchange membranes with high proton conduction performance

Polyoxometalates (POMs) are classified as solid superacids which can exhibit notable proton conductivity, making them a promising functional inorganic filler for enhancing the proton conductivity of proton exchange membranes (PEMs). In this study, a series of hybrid membranes were obtained by molecular-level hybridization of Weakley-type POM Na₇H₂LaW₁₀O₃₆ (LaW₁₀) clusters into sulfonated poly (aryl ether ketone sulfone) (SPAEKS). All hybrid membranes exhibited greater proton conductivity than the pristine membrane in the 30–80 °C temperature range. When the doping amount of LaW₁₀ reached 7 wt.%, the proton conductivity of M-LaW₁₀-7 achieved 64 mS·cm⁻¹ at 80 °C. Lanthanide ions' high coordination number property and variable coordination environment can aid to attract more water molecules from the environment. LaW₁₀ and these bound water can construct denser hydrogen bonds with –SO₃H of SPAEKS. These intensive hydrogen bonds will facilitate the constitution of more continuous proton transport channels, and improve the proton conductivity of the hybrid membrane. This work offers a fresh approach to using POMs containing rare-earth components in PEMs.