Directly deposited Nafion/TiO2 composite membranes for high power medium temperature fuel cells

This work presents a simple production method for TiO2 reinforced Nafion (R) membranes which are stable up to a 120 degrees C operation temperature. The novel TiO2 reinforced membranes yield a maximum power density of 2.02 W cm(-2) at 120 degrees C; H-2/O-2; 0.5/0.5 L min(-1); 90% RH, 300/300 kPa(abs). This is 2.8 times higher than the highest power density for TiO2 reinforced membranes so far published in literature. The described membranes even exceed the maximum power density of a commercial Nafion (R) HP membrane in an identical measurement setup at 100 degrees C and 120 degrees C. Compared to the commercial Nafion (R) HP membrane the maximum power density was increased by 27% and 9% at 100 degrees C and 120 degrees C, respectively. The membrane is manufactured by drop-casting a dispersion of Nafion (R) and TiO2 nanoparticles onto both the anode and cathode gas diffusion electrodes. Furthermore pure Nafion (R) membranes manufactured by the same method had higher membrane resistances at temperatures >100 degrees C than TiO2-reinforced Nafion (R) membranes.