Efficient and stable water electrolysis for hydrogen production using multi-cations-grafted poly (arylene piperidinium)-based anion exchange membranes

Anion exchange membranes (AEMs) are one of the core parts of anion exchange membrane water electrolyzers. However, the low ion conductivity and poor stability of AEMs in highly concentrated alkaline environment remain critical bottlenecks limiting the development of AEMWEs. To address this, we prepare multi-cation-grafted poly (p-terphenyl-piperidinium) membranes (PTP-TC- y ). The ether-free backbone and alkaline-stable piperidinium cation of PTP-TC- y can maintain long-term stability in alkaline environment. The atomic force microscope (AFM) images show that PTP-TC- y membranes form obvious microphase separation structures because of multi-cation side chain grafting, which is conducive to the construction of ion channels and improves the ion conductivity. Among the prepared AEMs, the PTP-TC-20 membrane has an outstanding ion conductivity of 143.1 mS cm −1 at 80 °C and retains 83.6% ion conductivity after immersing in 1 M KOH for 1920 h at 80 °C. The PTP-TC-20 membrane exhibits excellent cell performance, achieving 6.24 A cm −2 at 2 V and a low voltage decay rate of 1.5 mV h −1 during cycling in 1 M KOH at a current density of 1 A cm −2 for 120 h. These results verify that the prepared PTP-TC- y membranes have a good prospect for application in water electrolyzers.