Poly(Ethylene Piperidinium)s for Anion Exchange Membranes

Abstract The lack of anion exchange membranes (AEMs) that possess both high hydroxide conductivity and stable mechanical and chemical properties poses a major challenge to the development of high-performance fuel cells. Improving one side of the balance between conductivity and stability usually means sacrificing the other. Herein, we used facile, high-yield chemical reactions to design and synthesize a piperidinium polymer with a polyethylene backbone for AEM fuel cell applications. To improve the performance, we introduced ionic crosslinking into high-cationic-ratio AEMs, PEP80-20PS, to suppress high water uptake and swelling while further improving the hydroxide conductivity. Remarkably, PEP80-20PS achieved a hydroxide conductivity of 354.3 mS cm− 1 at 80°C while remaining mechanically stable. Compared with the base polymer PEP80, the water uptake and swelling rates of the ionically crosslinked sample at 80°C decreased substantially by 69% and 85%, respectively. PEP80-20PS also showed excellent alkaline stability, 84.7% remained after 35 days of treatment with an aqueous KOH solution. The chemical design in this study represents a significant advancement toward the development of simultaneously highly stable and conductive AEMs for fuel cell applications.