Robust multiblock poly(arylene alkylene) anion exchange membranes for water electrolysis

Engineering the polymer structure to create a well-defined microphase separation structure is the optimal approach to greatly improve the comprehensive performance of anion exchange membranes (AEMs). This work prepared novel poly( m -terphenyl ammonium-b-biphenyl phenyl)s (PmTPA-b-BPP (x)) that combine the structural advantages of twisted, multiblock, and long alkyl side chain tethered trimethylquaternary ammonium (TMA). PmTPA-b-BPP (x) has superior performance to p -terphenyl-based multiblock poly( p -terphenyl ammonium-b-biphenyl phenyl)s (PpTPA-b-BPP (y)) due to the more advanced microphase separation structure. It is worth noting that PmTPA-b-BPP (0.10) with 10 % content of hydrophobic segments exhibits an outstanding comprehensive performance, including considerable OH − conductivity (150.2 mS cm −1  at 80 °C), low swelling ratio (SR, 16.7 % at 80 °C), 31.3 MPa of tensile stress (TS, dry state), and 184.5 % of elongation at break (Eb, dry state). Besides, it presents good alkaline stability with 90.1 % retention ratio of cationic groups after 2160 h of accelerated aging testing (2 M KOH at 80 °C). Furthermore, the anion exchange membrane water electrolysis (AEMWE) equipping the PmTPA-b-BPP (0.10) membrane and utilizing Ni 2 Fe 1 as the anode catalyst obtains an outstanding current density of 4.7 A cm −2  at 1.9 V. And the related cell continuous water electrolysis for 1000 h at 1 A cm −2 , the voltage decay rate has been calculated to be only 80 μV h −1 .