Toward high conductivity in anion exchange membranes for alkaline fuel cells application

Quaternized poly(2,6-dimethylphenylene oxide) materials (PPOs) containing clicked 1,2,3-triazoles were first prepared through CuI-catalyzed \u201cclick chemistry\u201d to improve the anion transport in anion-exchange membranes (AEMs). Clicked 1,2,3-triazoles incorporated into AEMs provided more sites to form efficient and continuous hydrogen-bond networks between the water/hydroxide and the triazole for anion transport. Higher water uptake was observed for these triazole membranes. Thus, the membranes showed an impressive enhancement of the hydroxide diffusion coefficient and, therefore, the anion conductivities. The recorded hydroxide conductivity was 27.8\u201362\u2005mS\u2009cm 121 at 20\u2009\ub0C in water, which was several times higher than that of a typical PPO-based AEM (TMA-20) derived from trimethylamine (5\u2005mS\u2009cm 121). Even at reduced relative humidity, the clicked membrane showed superior conductivity to a trimethylamine-based membrane. Moreover, similar alkaline stabilities at 80\u2009\ub0C in 1\u2009M NaOH were observed for the clicked and non-clicked membranes. The performance of a H2/O2 single cell assembled with a clicked AEM was much improved compared to that of a non-clicked TMA-20 membrane. The peak power density achieved for an alkaline fuel cell with the synthesized membrane 1a(20) was 188.7\u2005mW\u2009cm 122 at 50\u2009\ub0C. These results indicated that clicked AEM could be a viable strategy for improving the performance of alkaline fuel cells.Peer reviewed: YesNRC publication: Ye