Anion Conductive Membrane Prepared by Plasma Polymerization for Direct Methanol Alkaline Fuel Cell

Direct methanol alkaline fuel cells have been tested to suppress methanol crossover and to improve the anodic activity in alkaline media. Plasma-polymerization with 4-vinylpyridine and hexafluoropropene followed by quaternization using 1-bromopropane was conducted to prepare an anion conductive ionomer in the catalyst layer and anion conductive membrane using a porous film. Plasma-polymerized membranes on various porous films were characterized by water uptake, ion conductivity and methanol permeability. The performance of the direct methanol alkaline fuel cell using the prepared anion conductive membrane was observed. The highest open circuit voltage (OCV) was 0.93 V for the 10-min-polymerized membrane and the highest short circuit current density (SCC) was 180 mA/cm2 for the 30-min-polymerized membrane. The water flux from the cathode to the anode along with the OH anion decreased with the decreasing moles of water vapor in the cathode feed, and water was observed to be transported backward from the anode to the cathode due to the low water content in the cathode feed