High Performance Anion Exchange Membrane Fuel Cells Enabled by Fluoropoly(olefin) Membranes

Although the peak power density of anion exchange membrane fuel cells (AEMFCs) has been raised from approximate to 0.1 to approximate to 1.4 W cm(-2) over the last decade, a majority of AEMFCs reported in the literature have not been demonstrated to achieve consistently high performance and steady-state operation. Poly(olefin)-based AEMs with fluorine substitution on the aromatic comonomer show considerably higher dimensional stability compared to samples that do not contain fluorine. More importantly, fluorinated poly(olefin)-based AEMs exhibit high hydroxide conductivity without excessive hydration due to a new proposed mechanism where the fluorinated dipolar monomer facilitates increased hydroxide dissociation and transport. Using this new generation of AEMs, a stable, high-performance AEMFC is operated for 120 h. When the fuel cell configuration is subjected to a constant current density of 600 mA cm(-2) under H-2/O-2 flow, the cell voltage declines only 11% (from 0.75 to 0.67 V) for the first 20 h during break-in and the cell voltage loss is low (0.2 mV h(-1)) over the subsequent 100 h of cell testing. The ease of synthesis, potential for low-cost commercialization, and remarkable ex situ properties and in situ performance of fluoropoly(olefin)-based AEM renders this material a benchmark membrane for practical AEMFC applications.