Enhancing proton conductivity of proton exchange membranes via anchoring imidazole-loaded MIL-101-NH2 onto sulfonated poly (arylene ether ketone sulfone) by chemical bonding

Summary Organic-inorganic modification by incorporating metal-organic frameworks to copolymers is one strategy to advance the properties of membranes. Here, the imidazole-loaded MIL-101-NH 2 (Im@MIL-101-NH 2 ) was prepared and chemically anchored onto sulfonated poly (arylene ether ketone sulfone) containing carboxyl groups (C-SPAEKS). The chemical stabilities, mechanical properties, and dimensional stabilities of compound membranes were increased. The highest tensile strength of C-SPAEKS-IM6 reach to 105.36 MPa. The weight retention rate of hybrid membranes was still higher than 90% after the oxidation stability test at 80°C. Furthermore, the introducing Im@MIL-101-NH 2 could construct new proton transport paths, and the amphiphilic imidazole molecules embedded inside Im@MIL-101-NH 2 could act as proton carriers. The C-SPAEKS-IM6 showed a maximum proton conductivity of 0.082 S cm −1 at 90°C. Additionally, the peak power density of C-SPAEKS-IM6 was 171.52 mW cm −2 . To sum up, this series of membranes have latent capacity in the application of fuel cells. Im@MIL-101-NH 2 was anchored on polymer backbones via the Hinsberg reaction. Chemical bonds between MOFs and polymer chains improved compatibility of two phases. Cross-linking structure enhanced the mechanical property and oxidative stability. The sulfonamide groups could devote protons and transport it to MOFs.