Hydrophilic and Hydrophobic Dual-side-linked Poly(carbazole-butanedione) Anion Exchange Membranes for Water Electrolysis and Fuel Cells Applications

To overcome the imbalance between high ionic conductivity, dimensional stability and strong alkali resistance in anion exchange membranes (AEMs), this work discarded the traditional polymer structure with cationic main chains, while prepared n-DTMA-PHCZBDO AEMs with different alkyl chain lengths by combining hydrophilic bi-cationic side chains and hydrophobic alkyl long side chains. The performance test results showed that membrane 6-DTMA-PHCZBDO has high ionic conductivity (169.2 mS cm -1 ), good dimensional stability (WU 140.3 %, SR 30.1 %) and excellent mechanical properties (55.3 MPa). Particularly, the ionic conductivity and tensile strength degradation rate of membrane 6-DTMA-PHCZBDO were less than 10 % after stabilization in 2 M NaOH at 80 °C for 2000 h, showing outstanding alkali resistance. Besides, It not only exhibited low resistance (R ohm 0.134 Ω cm 2 and R ct 0.035 Ω cm 2 ), high current density at 40 °C (1.00 A cm -2 ), 50 °C (1.83 A cm -2 ) and 60 °C (2.40 A cm -2 ) in 2.2V, but also showed good durability (degradation rate 1.71 mV h -1 , at 1000 mA cm -2 for 60 h) in anion exchange membrane water electrolysis (AEMWEs). Importantly, membrane 6-DTMA-PHCZBDO could be well realized for dual application of AEMWEs and fuel cells, which also had good H 2 -O 2 fuel cell power density (490.93 mW cm -2 ). Therefore, the hydrophilic and hydrophobic dual side linking branches can enhance the comprehensive performance of AEMs and can facilitate the application of it in AEMWEs and H 2 -O 2 fuel cell.