High Performance Anion Exchange Membranes with Confined Sub‐2‐nm Ion Channel

Abstract As a key component of low‐cost anion exchange membrane fuel cells (AEMFCs), anion exchange membranes (AEMs) are far from commercial application, because of dissatisfactory alkaline stability and conductivity. Herein, a new insight is proposed to prepare high performance AEMs by constructing of confined ion channel. With an intermediate oligomer produced before the main copolymerization, novel poly(vinyl‐carbazolyl aryl piperidinium) AEMs with confined sub‐2‐nm ion channel are successfully prepared. The unique sub‐2‐nm ion channel enable membranes ultrahigh hydroxide conductivity of 261.6 mS cm −1 , and the state‐of‐the‐art chemical stability over 5000 h. Moreover, the AEMs also exhibit good mechanical stability with lower water uptake and dimensional swelling. Based on the as‐prepared AEMs and ionomer, fuel cells exhibit outstanding peak power density of 1.8 and 0.2 W cm −2 with Pt‐based catalysts and completely non‐precious metal catalysts, respectively.