Valeria Felice

Composite polymer electrolytes for fuel cell applications: filler-induced effect on water sorption and transport properties.

Nafion- and sulfonated polysulfone (SPS)- based composite membranes were prepared by incorporation of SnO2 nanoparticles in a wide range of loading (0

Functionalized Metal Oxides for PEMFC Applications

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An Investigation of Inorganic/Ionomer Composite Electrolyte Membranes by Dynamic Vapor Sorption

35 wt.u2009%). The composites were investigated by differential scanning calorimetry, dynamic vapor sorption and electrochemical impedance spectroscopy to study the filler effect on water sorption, water mobility, and proton conductivity. A detrimental effect of the filler was observed on water mobility and proton conductivity of Nafion-based membranes. An increase in water mobility and proton conductivity was instead observed in SPS-based samples, particularly at low hydration degree. Analysis of the water sorption isotherms and states of water revealed that the presence of SnO2 in SPS enhances interconnectivity of hydrophilic domains, while not affecting the Nafion microstructure. These results enable the design of suitable electrolyte materials that operate in proton exchange membrane fuel cell conditions.

On the proton conductivity of Nafion–Faujasite composite membranes for low temperature direct methanol fuel cells

A synthetic strategy for the surface functionalization of ZrO2 nnanoparticles was developed to obtain ceramic materials with nimproved proton conductivity to be used as fillers in proton nconducting membranes for fuel cell applications. The procedure nconsisted in condensation of the oxide surface hydroxyl groups nwith 3-mercaptopropyltrimethoxy silane, followed by oxidation of nthe thiol group into sulfonic acid. The morphology, chemical nstructure and composition of the functionalized oxide were ninvestigated by differential thermal analysis (DTA), Fourier nTransform Infrared Spectroscopy (FT-IR) and Field Emission nScanning Electron Microscopy (FE-SEM). Thermal analysis ndemonstrated the good thermal and hydrothermal stability of this nnew material. The proton transport features of the oxide were ninvestigated by measuring ion exchange capacity (IEC) and proton nconductivity (σ), demonstrating that the surface functionalization nprocedure enhanced the proton transport feature of zirconium noxide.

DSC and DVS Investigation of Water Mobility in Nafion/Zeolite Composite Membranes for Fuel Cell Applications

Nafion-Faujasite zeolite composite membranes were prepared by nsolution casting at different zeolite content, ranging from 2 to 40 nwt.% nominal content. A dynamic vapor sorption (DVS) apparatus nwas used to investigate the thermodynamics of water sorption of nthe composite electrolytes. The water diffusivity was estimated nfrom the kinetics of the water adsorption process. Fitting the nsorption isotherms by a multi-mode model allowed to discriminate nthe water states in the composites and analyze the effect of the nadditives on the interaction of water with the ionomer matrix. The naddition of zeolites causes an increase of the mobile water npopulation within the membrane.