Formation of a high conductivity fuel cell electrolyte by pressing diphenylsiloxane-based inorganic-organic hybrid particles

Abstract

An inorganic-organic nanohybrid particle with a two-dimensional chain structure, diphenylsiloxane-silica (Ph2SiO-SiO2), was prepared by sol-gel process using diphenyldiethoxysilane (DPDES) and tetraethoxysilane (TEOS), and a high proton conducting polymer of poly(2-acrylamido-2-methyl-1-propane sulfonic acid) (PAMPS) was deposited on the Ph2SiO-SiO2 particles via layer-by-layer assembly. A flexible sheet-like electrolyte was successfully obtained from the resulting PAMPS-deposited particles by pressing. The proton conductivity of the sheet prepared using unmodified Ph2SiO-SiO2 particles was lower than 10-9 S/cm at 80°C. On the other hand, the PAMPS-deposited samples showed proton conductivities ∼7 orders of magnitude higher than those of the sample prepared using unmodified particles, and their conductivity reached about 1 × 10-2 S/cm at 80°C and 80% relative humidity. This is ascribed to the PAMPS layer being concentrated at the particle interfaces, which percolated throughout the monolithic sample. © 2008 The American Ceramic Society.