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 (H-2-O-2) 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.

Automated summary

Anion exchange membrane fuel cells (AEMFCs) have the advantage of low cost, but the use and commercialization of anion exchange membranes (AEMs) have always been challenging. This study successfully prepared AEMs and ionomers with non-rotatable rigid carbazole group and piperidinium group, and demonstrated their excellent performance in conductivity, mechanical strength, and stability. Moreover, the fuel cell based on these materials showed outstanding peak power density and long-term stability.