Pendant meta-Piperidinium-Based Anion Exchange Membranes with Enhanced Alkaline Stability for Water Electrolysis

Alkaline stability is a critical challenge for anion exchange membranes (AEMs) in energy conversion and storage devices. Although stable dimethylpiperidinium is an ideal moiety for the construction of AEMs, its stability diminished significantly when it was incorporated into the polyarylpiperidinium polymer. Herein, poly(arylmethyl m-piperidinium) (m-PAMP) was easily synthesized by using highly active purchasable monomers with only 50% superacid usage compared with conventional methods. This rational design strategy simultaneously reduces the β-H content and diminishes the backbone effect on piperidinium, improving the upper limit of the alkaline stability of piperidinium-based AEMs. m-PAMP showed no E2 elimination or backbone degradation after 4000 h at 80 °C in 1 M KOH. A fully nonprecious-metal catalyst water electrolyzer assembled with m-PAMP not only achieved exceptional performance (8.31 A cm–2 at 2 V) but also maintained stability for over 1900 h under 2 A cm–2, highlighting the substantial potential of m-PAMP for advancing sustainable hydrogen production technologies.