A facile approach to fabricating organosilica layered material with sulfonic groups as an efficient filler for polymer electrolyte nanocomposites

We report the one-pot synthesis of a siliceous layered material bearing sulfonic group functionalities through the simple sol-gel process of 3-(trihydroxy silyl) propyl-1-propane-sulfonic acid. This easy-fabricated layered nanomaterial can possess a high number of organo-sulfonic groups, rendering it an attractive, multifunctional filler for polymer electrolyte nanocomposites for energy applications such as lithium batteries and fuel cells. X-ray diffraction and photoelectron spectroscopy confirm the layered structure and the presence of sulfonic groups, respectively. In the present work, the silica nanomaterial was tested as a nanofiller for the development of innovative Nafion nanocomposite membranes for proton exchange membrane fuel cells (PEMFCs). Pristine functional material and nanocomposites were characterized by a combination of analytical techniques. The dynamic mechanical analysis showed that composite membranes are much stiffer and can withstand higher temperatures than recast Nafion membrane. Proton transport properties and water management were investigated by 1H pulsed field gradient (PFG) NMR spectroscopy, by measuring the water self-diffusion coefficients in a wide temperature range (20-130 °C). The data showed a remarkable high water retention capacity of composite membranes and high proton diffusion in the temperature region above 100 °C, representing a significant advance in the current state-of-the-art technology of PEMFCs.