Phosphotungstic Acid Supported on a Nanopowdered ZrO₂ as a Filler in Nafion‐Based Membranes for Polymer Electrolyte Fuel Cells

Abstract

An inorganic filler prepared by impregnation of phosphotungstic heteropolyacid on zirconia (HPW/Zr) was developed to be inserted into a perfluorosulphonic polymer matrix for a polymer electrolyte fuel cell (PEFC) operating at a medium temperature (80–120 °C) and low relative humidity (RH). Two different phosphotungstic acid (PWA) loadings (30 and 45% w/w) were anchored on a nanopowdered ZrO2. Such compounds were characterised by different techniques: differential scanning calorimetry (DSC), X‐ray diffraction (XRD), energy dispersive X‐ray analysis (EDX) and porosity and surface area by Brunauer–Emmett–Teller (BET), to verify the introduction and anchorage of PWA on ZrO2. Two composite Nafion membranes were prepared and characterised in terms of chemical–physical characteristics and electrochemical tests. Thermogravimetric analysis (TGA) provided evidence that HPW/Zr had been incorporated into composite membranes and it was not eluted. A good proton conductivity of about 6 × 10–3 S cm–1 at 120 °C and 25% RH was recorded.Accelerated in situ ageing tests highlighted a good electrochemical stability (more than 150 cycles at 90 °C with dry gases) of the composite membranes with a slow decay and a reasonable integrity of the analysed membrane‐electrodes assembly (MEA). Finally, a post‐mortem SEM–EDX analysis on MEAs confirmed the presence of HPW/Zr in the membrane after the in situ testing.

Advanced nanocomposite membranes for fuel cell applications: a comprehensive review

“…In order to increase the stability and the surface area, two approaches have been suggested. The first involves fixation of the POMs on support oxides such as SiO2, Al2O3, ZrO2, and TiO2 (Saccà et al, 2008 (Ramani et al, 2005b). This second approach was investigated by Amirinejad et al (2012).…”

Nafion<SUP>®</SUP> Electro-Spun Reinforced Membranes for Polymer Electrolyte Fuel Cell

“…A 10% wt/wt Nafion solution was obtained by dissolving the dry residue in dimethylacetamide (DMAc). 17 The electrospinning solutions were prepared by adding the PVP or PS amount to the Nafion solution ranging between 0 and 10% wt compared to the dry Nafion content. PVP (Mw = 1,300,000) and PS (Mw = 280,000) (Sigma Aldrich) were used as binders; they were added to the Nafion solution maintained at 60 C under stirring for 3 hours.…”

Perfluorinated Sulfonic Acids as Proton Conductor Membranes

“…Three main synthetic procedures were used to prepare the Nafion-metal oxide-heteropolyacid composite membranes: (1) impregnation of the heteropolyacid, dispersion of the impregnated oxide within a Nafion solution, and membrane formation by casting of the Nafion-oxideheteropolyacid mixture [68][69][70][71]; (2) formation of oxide particles by sol-gel within a pre-formed Nafion membrane and subsequent impregnation of the heteropolyacid onto the oxide [72]; and (3) hydrolysis of oxide precursors within a Nafion solution in the presence of the heteropolyacid and subsequent membrane formation by casting [73].…”