Characterisation of a re-cast composite Nafion ® 1100 series of proton exchange membranes incorporating inert inorganic oxide particles

Abstract

A series of cation exchange membranes was produced by impregnating and coating both sides of a quartz web with a Nafion ® solution (1100 EW, 10%wt in water). Inert filler particles (SiO 2, ZrO 2 or TiO 2; 5–20%wt) were incorporated into the aqueous Nafion ® solution to produce robust, composite membranes. Ion-exchange capacity/equivalent weight, water take-up, thickness change on hydration and ionic and electrical conductivity were measured in 1 mol dm −3 sulfuric acid at 298 K. The TiO 2 filler significantly impacted on these properties, producing higher water take-up and increased conductivity. Such membranes may be beneficial for proton exchange membrane (PEM) fuel cell operation at low humidification. The PEM fuel cell performance of the composite membranes containing SiO 2 fillers was examined in a Ballard Mark 5E unit cell. While the use of composite membranes offers a cost reduction, the unit cell performance was reduced, in practice, due to drying of the ionomer at the cathode.