Construction of efficient ion transport and robust alkaline resistance by incorporating cationic metal-organic framework into multi-cationic imidazole functionalized poly (phenylene ether)

In this paper, cationic MIL-101-NH 2 (C-T-MOF) was synthesized by modified MIL-101-NH 2 . In order to reduce the erosion of functional sites by OH − , the amino group on the MIL-101-NH 2 framework was modified with a trimethyl quaternary ammonium group to obtain a C-T-MOF metal-organic framework with greater spatial hindrance. Afterwards, Im-PPO was prepared by imidazole functionalized PPO, Im-PPO-x was obtained by grafting the cationic 1-allyl-3-methylimidazole chloride (AMIMCl). Subsequently, the series of Im-PPO-1/C-T-MOF-x% AEMs were constructed through a composite preparation process, utilizing C-T-MOF as the filler phase and Im-PPO-1 as the continuous phase. The structure of the composite membranes was characterized by FT-IR and PXRD, and the experimental findings illustrated that the composite membranes were successfully prepared. As demonstrated by the performance results, the conductivity of Im-PPO-1/C-T-MOF-1% composite membrane reached a maximum value of 0.153 S cm −1 (80 °C, 100% RH), and the tensile strength was 44.93 MPa. In addition, the Im-PPO-1/C-T-MOF-1% composite membrane can still reach 90.3% of the initial conductivity after being immersed in NaOH solution (1 M) at 60 °C for 720 h. The findings demonstrated that the composite membranes exhibited elevated levels of ionic conductivity, good tensile strength and alkali resistance stability. In conclusion, the cationic MIL-101-NH 2 (C-T-MOF) made a significant contribution to the enhancement of the overall performance of composite anion exchange membranes.