Self-assembled Nafion-silica nanoparticles for elevated-high temperature polymer electrolyte membrane fuel cells

In this paper, a novel Nafion/SiO2 nanocomposite membrane based on the self-assembled Nafion-SiO2 nanoparticles was developed. The average particle size of Nafion-SiO2 nanoparticles prepared by self-assembly process was 2.8 +/- 0.5 nm. The self-assembled Nafion-SiO2 nanoparticles significantly enhance the durability of the Nafion/silica nanocomposite membrane as compared to that of conventional Nafion/silica composite and Nafion 212 membranes under wet/dry cyclic tests at 90 degrees C. With an addition of 5 wt% self-assembled Nafion-SiO2 nanoparticles, the Nafion/SiO2 nanocomposite membrane shows a significantly improved performance stability at cell/humidifying temperatures of 100 degrees C/60 degrees C under a current density of 600 mA/cm(2), and the degradation rate is 0.12 mV/min, almost 20 times lower than 2.33 mV/min measured on the pristine Nafion 212 membrane under the same conditions. The present results demonstrate the promises of the self-assembled Nafion/SiO2 nanocomposite membrane for elevated-high temperature PEM fuel cells applications. (c) 2007 Elsevier B.V. All rights reserved.