High performance poly(carbazolyl aryl piperidinium) anion exchange membranes for alkaline fuel cells

Anion exchange membrane fuel cells (AEMFCs) is a potential substitute to the prevailing proton exchange membrane fuel cells (PEMFCs), since non-precious metal catalysts can be applied in the AEMFCs, leading to much lower cost of it. However, anion exchange membranes (AEMs), as a crucial component of the AEMFCs, has always been a challenge in the commercialization of AEMFCs, such as poor life-time and conductivity. Herein, a series of poly(carbazolyl aryl piperidinium) AEMs and ionomers are prepared with non-rotatable rigid carbazole group next to piperidinium ring on the polymer backbone for the first time, and the membranes were fabricated by mass production method of tape-casting. The membranes exhibit extraordinary comprehensive performance, for instance, high hydroxide conductivity up to 204.8 mS cm−1 at 90 °C, good mechanical strength of >50 MPa in wet state, low hydrogen permeability and excellent alkaline stability of only 3% decline after 2100 h in 1 M KOH at 80 °C. Fuel cell (H2–O2) based on the as-prepared membranes and ionomers shows outstanding peak power density of 1.72 W cm−2 at a quite low back pressure of 20 kPa, and only 2.6% decay was observed after 120 h.