Nanocomposite Electrolyte Membranes Research Articles

Durability of Nafion-hydrophilic silica hybrid membrane against trace radial species in polymer electrolyte fuel cells

Durability of an organic–inorganic nanocomposite electrolyte membrane prepared by mixing hydrophilic fumed silica particles of an average size of 7nm with Nafion ionomer was studied for the mitigation of chemical degradation of the membrane caused by trace radial species in polymer electrolyte fuel cells (PEFCs). Infrared (IR) spectroscopy indicated that the peak of C−F, S−O and C−O−C bands were not shifted to the higher wavenumber with an addition of 1wt.% hydrophilic silica to the Nafion matrix. This suggests that hydrophilic silica had a catalyst activity for the decomposition of hydrogen peroxide and reduced the membrane degradation by trace radicals attack. Quantum chemical calculations (QCCs) using a model ionomer of trifluoromethanesulfonate (TFMS) and a model nanoparticle of Si(OH)4 also implied that the nanoparticle was able to trap H, OH and OOH radical species before attacking the ionomer. The hydration of TFMS that induces deprotonation of sulfonic acid group in TMFS and formation of hydronium anion was confirmed also in the presence of trace radicals due to the ability of Si(OH)4 to trap H radical.

A quasi solid state dye-sensitized solar cell based on poly(vinylidenefluoride-co-hexafluoropropylene)/SBA-15 nanocomposite membrane

Poly(vinylidenefluoride-co-hexafluoropropylene)/SBA-15 molecular sieves (designated as P(VDF-HFP)/SBA-15) nanocomposite membranes were prepared by a solution casting method. Prior to blending, the SBA-15 molecular sieves were impregnated with dimethylpropylimidazolium iodide (DMPII) ionic liquid. The P(VDF-HFP)/SBA-15 nanocomposite membranes were characterized using scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and AC impedance spectroscopy. The room temperature ionic conductivity of the P(VDF-HFP)/SBA-15A nanocomposite polymer electrolyte was of the order of around 10−3Scm−1. The quasi-solid-state dye-sensitized solar cells (DSSCs) were assembled by using photo-electrodes of TiO2 films on FTO/glass and the counter electrode based on the pulsed-plated Pt films. P(VDF-HFP)/I-SBA-15 nanocomposite electrolyte membrane containing dimethylpropylimidazolium iodide (DMPII) provides the best energy conversion efficiency of ca. 5.29%. This result indicates that the P(VDF-HFP)/I-SBA-15 nanocomposite membrane is a good candidate for a quasi-solid-state DSSC applications.

Sulfonated Titanium Nanotubes Based Nanocomposite Blend Membranes for Fuel Cell Applications

New nano-composite electrolyte membranes with good electrical and mechanical properties have been developed using various blend compositions of poly(1-vinylimidazole) (PVIm), poly(vinylidenefluoride-co-hexafluoropropylene) (PVdF-HFP) and trifluoromethansulfonic acid (TA) with sulfonated nano-tubular titania (sTNT). Sulfonated nano-tubular titania and nanocomposite membranes have been successfully synthesized using in house acid-functionalised nano-tubular titania which was synthesized using hydrothermal method. Investigations of the synthesized membranes yield results of elevated conductivity and stability at temperatures in excess of 120°C. Conductivity values of 10-3 S/cm have been noted within these membranes and the morphology has also been found to improve with the addition of sulfonated nano-tubular titania. The nano-composite membranes also shows decrease in the water uptake with the addition of nano-tubular titania.

Laser printing of nanocomposite solid-state electrolyte membranes for Li micro-batteries

The electrochemical and mechanical properties of nanocomposite solid-state electrolyte membranes deposited using a laser direct-write technique from a suspended solution comprised of an ionic liquid (1,2-dimethyl-3- n-butylimidazolium-bis-trifluoromethanesulfonylimide)–polymer (poly(vinylidene fluoride-co-hexafluoropropylene)) matrix with dispersed nano-particles (TiO 2) are reported and discussed. These laser printed nanocomposite solid-state membranes are shown to exhibit the proper electrochemical behavior for ionic liquids while maintaining the strength and flexibility of the polymer matrix. This combination of physical properties and deposition technique makes these deposited nanocomposite membranes ideally suited for use as an electrolyte/separator in Li micro-batteries. Sample Li micro-batteries using these laser printed nanocomposite membranes have been fabricated and their charge/discharge behavior tested, demonstrating the feasibility of using these nanocomposite membranes in Li micro-battery applications.

Preparation and characterization of proton-conducting CsHSO4–SiO2 nanocomposite electrolyte membranes

Microstructures and conductivity characteristics were investigated in proton-conducting CsHSO4–SiO2 composite electrolyte membranes prepared by CsHSO4 melt infiltration into porous SiO2 membranes with average pore sizes of 290 and 4 nm, respectively. XRD and TG-DTA analyses revealed that the pore-filled CsHSO4 proton-conducting phases in the nanocomposite electrolyte with the 290-nm SiO2 pores consisted of two crystallized CsHSO4 bulk phases and an amorphous CsHSO4 interface phase. For the electrolyte with 4-nm SiO2 pores, however, only the amorphous CsHSO4 interface phase dispersed with CsHSO4 crystallites was present in the nanocomposite. AC impedance measurements indicated that the proton-conducting characteristic of the nanocomposite with the 290-nm SiO2 membrane pores was similar to that of the pure CsHSO4 electrolyte, whereas the nanocomposite with 4-nm pores exhibited a high-temperature CsHSO4 proton-conducting characteristic across the entire testing temperature range, from nearly room temperature up to 200 °C, thus showing a significant enhancement in low-temperature conductivity vs. the pure CsHSO4 electrolyte—by two to three orders of magnitude. Moreover, the amorphous CsHSO4 interface phase in the nanocomposite with the 4-nm SiO2 pores was demonstrated to be stable even after having been kept at 40 °C for 1 week.

Thailand: Degussa — fumed silica

Durability of an organic–inorganic nanocomposite electrolyte membrane prepared by mixing hydrophilic fumed silica particles of an average size of 7 nm with Nafion ionomer was studied for the mitigation of chemical degradation of the membrane caused by trace radial species in polymer electrolyte fuel cells (PEFCs). Infrared (IR) spectroscopy indicated that the peak of C−F, S−O and C−O−C bands were not shifted to the higher wavenumber with an addition of 1 wt.% hydrophilic silica to the Nafion matrix. This suggests that hydrophilic silica had a catalyst activity for the decomposition of hydrogen peroxide and reduced the membrane degradation by trace radicals attack. Quantum chemical calculations (QCCs) using a model ionomer of trifluoromethanesulfonate (TFMS) and a model nanoparticle of Si(OH)4 also implied that the nanoparticle was able to trap H, OH and OOH radical species before attacking the ionomer. The hydration of TFMS that induces deprotonation of sulfonic acid group in TMFS and formation of hydronium anion was confirmed also in the presence of trace radicals due to the ability of Si(OH)4 to trap H radical.