Hygroscopic-oxides/Nafion® hybrid electrolyte for direct methanol fuel cells

Hygroscopic-oxides/Nafion® hybrid membranes were prepared using an infiltration sol–gel process, and the effects of infiltrated oxides on transport and direct methanol fuel cell (DMFC) properties were investigated at 25 °C. The inorganic contents were controlled by the infiltration time. Methanol permeability decreased with increasing infiltrated oxides. Spin-lattice relaxation measurements using 1H nuclear magnetic resonance (1H NMR) spectroscopy suggested that the ionic channels of Nafion® become narrow after infiltrating oxides. The hybrid membrane infiltrated with around 3 wt% oxides showed better DMFC performance than Nafion®. Impedance analysis suggested that the infiltrated oxides effectively reduce the charge transfer resistance.