Review of the proton exchange membranes for fuel cell applications

Sulfonated poly(ether ether ketone)-based silica nanocomposite membranes for direct ethanol fuel cells

Sulfonated poly( ether ether ketone)-silica membranes doped with phosphotungstic acid. Morphology and proton conductivity

The synthesis and characteristics of high-temperature proton-exchange membranes based on mesoporous silica nanocomposite functionalized with phosphotungstic acid (HPW) were investigated in detail for applications in proton-exchange membrane fuel cells (PEMFCs) and direct methanol fuel cells (DMFCs). The HPW–meso-silica nanocomposites were characterized by small-angle X-ray scattering (SAXS), FTIR spectroscopy, Raman spectroscopy, TGA, N2 absorption isotherm, water uptake, TEM, conductivity, and fuel cell performance. The spectroscopy results indicate interactions between the Keggin anions of HPW and meso-silica and the possible formation of (≡SiOH2+)(H2PW12O40–) species. The results show that the proton conductivity of the HPW–meso-silica nanocomposites depends strongly on the content of HPW. The threshold for the proton conductivity of the nanocomposite is ∼10 wt %. The best proton conductivity is 0.07 S cm–1 at 25 °C under 100% relative humidity (RH) with an activation energy of ∼14 kJ mol–1, obtained o...

Characterization of High-Temperature Proton-Exchange Membranes Based on Phosphotungstic Acid Functionalized Mesoporous Silica Nanocomposites for Fuel Cells

Modified SPEEK membranes for direct ethanol fuel cell

Polymer blend of sulfonated poly(oxy-1,4phenyleneoxy-1,4phenylenecarbonyl-1,4phenylene) (SPEEK) and poly(ether sulfone) (PES) was compounded with commercial and synthesized silica. PES phase had important role to improve the stability and to reduce permeability of sulfonated matrix to alcohol solution, but it also reduced the proton conductivity of membrane. The addition of synthesized silica, which had heteropolyacid phosphotungstic acid (HPW) occluded inside the silica matrix (SiO2 · HPW) was evaluated to improve the conductivity.

Nanocomposite Membranes Based on Sulfonated Poly(etheretherketone) Structured with Modified Silica for Direct Ethanol Fuel Cell

Composite polymer membranes based on sulfonated poly(arylene ether sulfone) (SPSU) containing benzimidazole derivatives (BIzD) and heteropolyacid for use in fuel cells were prepared. The effects of both the increment in BBIzD component and the procedure of mixing on the morphology and proton conductivity were investigated. The heteropolyacid (HPA) extracted in water decreased with the addition of BBIzD in the composite. The interactions developed among the sulfonate groups, the benzimidazole derivatives and the HPA were verified by Fourier transform infrared (FTIR). The network of interactions established in the composite membrane based on SPSU containing benzimidazole derivatives and phosphotungstic acid (HPW) in the ratio of SPSU/BBIzC 4 (8:1) in equivalents and SPSU/HPW(7:3) in mass resulted in a very high proton conductivity at no °C.

Luisa Magno de Carvalho

Papers

Nanocomposite Membranes Based on Sulfonated Poly(etheretherketone) Structured with Modified Silica for Direct Ethanol Fuel Cell

Nanostructured Proton-Conducting Membranes for Fuel Cell Applications