Hybrid organic-inorganic nanostructured membranes for high temperature proton exchange membranes fuel cells (PEMFC)

Compared to internal combustion engines, proton-exchange membrane fuel cells (PEMFC) operate with zero emissions of environmental pollutants being this an adequate choice for transportation field. The increase of the operation temperature of PEMFC above 130°C is a great concern for the commercial application of the cells in electric vehicles. Hybrid organic-inorganic nanostructured membranes can combine the main properties to meet this objective: high proton conductivity along with thermal and chemical stability. The possibilities of synthesis of these hybrid structures grow exponentially with the combination of sol-gel chemistry and monomers. Three different approaches have been followed for obtaining hybrid membranes that present the properties needed for application in high temperature PEMFC: development of methacrylate and epoxy structures, and optimization of the inorganic component incorporating phosphorus. Proton conductivity has been endowed on the base of three strategies: a high concentration of hydroxyl groups from inorganic component, \({\rm SO}_3^-\) groups through sulfonation of phenyl rings, and incorporation of tungstophosphoric acid, H3[P(W3O10)4].