“…The P max values increased to 250 mW cm −2 and 272 mW cm −2 for the 2 M and 4 M methanol feeds, respectively. The ability to operate at 4 M methanol is advantageous, as other membranes are optimal for 1 M or 2 M methanol feed [20,73]. The results confirm that our developed QPVA/CTAB-coated LaFeO 3 membrane has good methanol barrier properties and integral structure.…”
Section: Direct Alkaline Methanol Fuel Cell Performancesupporting
confidence: 68%
“…The morphology and microstructure of the nanoparticles and membrane composites were analysed using a transmission electron microscope (TEM), a high-resolution TEM (HRTEM), and a field emission scanning electron microscope (FESEM) equipped with an energy dispersive X-ray (EDX) detector [18,54,73]. The crystalline behaviours of the nanoparticles and composite membranes were assessed via X-ray diffraction (XRD) analyser and differential scanning calorimeter (DSC) [18,53,55].…”
Section: Physicochemical Properties Of Nanoparticles and Nanocompositmentioning
Perovskite LaFeO 3 nanofillers (0.1%) are incorporated into a quaternized poly(vinyl alcohol) (QPVA) matrix for use as hydroxide-conducting membranes in direct alkaline methanol fuel cells (DAMFCs). The as-synthesized LaFeO 3 nanofillers are amorphous and functionalized with cetyltrimethylammonium bromide (CTAB) surfactant. The annealed LaFeO 3 nanofillers are crystalline without CTAB. The QPVA/CTAB-coated LaFeO 3 composite membrane shows a defect-free structure while the QPVA/annealed LaFeO 3 film has voids at the interfaces between the soft polymer and rigid nanofillers. The QPVA/CTAB-coated LaFeO 3 composite has lower methanol permeability and higher ionic conductivity than the pure QPVA and QPVA/annealed LaFeO 3 films. We suggest that the CTAB-coated LaFeO 3 provides three functions to the polymeric composite: increasing polymer free volume, ammonium group contributor, and plasticizer to enhance the interfacial compatibility. The composite containing CTAB-coated LaFeO 3 results in superior cell performance. A maximum power density of 272 mW cm −2 is achieved, which is among the highest power outputs reported for DAMFCs in the literature.
“…The P max values increased to 250 mW cm −2 and 272 mW cm −2 for the 2 M and 4 M methanol feeds, respectively. The ability to operate at 4 M methanol is advantageous, as other membranes are optimal for 1 M or 2 M methanol feed [20,73]. The results confirm that our developed QPVA/CTAB-coated LaFeO 3 membrane has good methanol barrier properties and integral structure.…”
Section: Direct Alkaline Methanol Fuel Cell Performancesupporting
confidence: 68%
“…The morphology and microstructure of the nanoparticles and membrane composites were analysed using a transmission electron microscope (TEM), a high-resolution TEM (HRTEM), and a field emission scanning electron microscope (FESEM) equipped with an energy dispersive X-ray (EDX) detector [18,54,73]. The crystalline behaviours of the nanoparticles and composite membranes were assessed via X-ray diffraction (XRD) analyser and differential scanning calorimeter (DSC) [18,53,55].…”
Section: Physicochemical Properties Of Nanoparticles and Nanocompositmentioning
Perovskite LaFeO 3 nanofillers (0.1%) are incorporated into a quaternized poly(vinyl alcohol) (QPVA) matrix for use as hydroxide-conducting membranes in direct alkaline methanol fuel cells (DAMFCs). The as-synthesized LaFeO 3 nanofillers are amorphous and functionalized with cetyltrimethylammonium bromide (CTAB) surfactant. The annealed LaFeO 3 nanofillers are crystalline without CTAB. The QPVA/CTAB-coated LaFeO 3 composite membrane shows a defect-free structure while the QPVA/annealed LaFeO 3 film has voids at the interfaces between the soft polymer and rigid nanofillers. The QPVA/CTAB-coated LaFeO 3 composite has lower methanol permeability and higher ionic conductivity than the pure QPVA and QPVA/annealed LaFeO 3 films. We suggest that the CTAB-coated LaFeO 3 provides three functions to the polymeric composite: increasing polymer free volume, ammonium group contributor, and plasticizer to enhance the interfacial compatibility. The composite containing CTAB-coated LaFeO 3 results in superior cell performance. A maximum power density of 272 mW cm −2 is achieved, which is among the highest power outputs reported for DAMFCs in the literature.
“…9 ) due to the blocking effect [ 10 ]. The strong hydrogen bonding also diminished the pathways for absorbance of the ionic group into the polymer [ 32 ]. Fig.…”
Section: Resultsmentioning
confidence: 99%
“…Bayer et al [ 31 ] prepared a GO paper, which showed hydrogen permeability three times lower than Nafion and proton conductivity of 49.9 mScm −1 using an in-plane technique. The direct liquid fuel cell (DLFC) performance was excellent when Lue et al [ 32 ] introduced GO into Nafion. However, the performance of GO as a proton conductor is limited because it lacks functional groups that can be proton carriers in the membrane, which adversely affects proton conductivity and decreases fuel cell performance [ 19 ].…”
The high methanol crossover and high cost of Nafion® membrane are the major challenges for direct methanol fuel cell application. With the aim of solving these problems, a non-Nafion polymer electrolyte membrane with low methanol permeability and high proton conductivity based on the sodium alginate (SA) polymer as the matrix and sulfonated graphene oxide (SGO) as an inorganic filler (0.02-0.2 wt%) was prepared by a simple solution casting technique. The strong electrostatic attraction between -SO3H of SGO and the sodium alginate polymer increased the mechanical stability, optimized the water absorption and thus inhibited the methanol crossover in the membrane. The optimum properties and performances were presented by the SA/SGO membrane with a loading of 0.2 wt% SGO, which gave a proton conductivity of 13.2 × 10−3 Scm−1, and the methanol permeability was 1.535 × 10−7 cm2 s−1 at 25 °C, far below that of Nafion (25.1 × 10−7 cm2 s−1) at 25 °C. The mechanical properties of the sodium alginate polymer in terms of tensile strength and elongation at break were improved by the addition of SGO.
“…This may be due to the GO-Fe3O4 nanofillers having a high apparent aspect ratio [22,37] and being well-aligned by the magnetic field in the CL-QPVA matrix further suppressed the methanol permeation through the membranes. Well-aligned GO-Fe3O4 nanofillers created higher tortuosity in the polymer phase for methanol diffusion than the randomly distributed nanofillers.…”
Section: Ionic Conductivity Of Koh-doped Quaternized Polyvinyl Alcohomentioning
This work aims to clarify the effect of magnetic graphene oxide (GO) reorientation in a polymer matrix on the ionic conduction and methanol barrier properties of nanocomposite membrane electrolytes. Magnetic iron oxide (Fe 3 O 4 ) nanoparticles were prepared and dispersed on GO nanosheets (GO-Fe 3 O 4 ). The magnetic GO-Fe 3 O 4 was imbedded into a quaternized polyvinyl alcohol (QPVA) matrix and crosslinked (CL-) with glutaraldehyde (GA) to obtain a polymeric nanocomposite. A magnetic field was applied in the through-plane direction during the drying and film formation steps. The CL-QPVA/GO-Fe 3 O 4 nanocomposite membranes were doped with an alkali to obtain hydroxide-conducting electrolytes for direct methanol alkaline fuel cell (DMAFC) applications. The magnetic field-reoriented CL-QPVA/GO-Fe 3 O 4 electrolyte demonstrated higher conductivity and lower methanol permeability than the unoriented CL-QPVA/GO-Fe 3 O 4 membrane or the CL-QPVA film. The reoriented CL-QPVA/GO-Fe 3 O 4 nanocomposite was used as the electrolyte in a DMAFC and resulted in a maximum power density of 55.4 mW·cm −2 at 60 • C, which is 73.7% higher than that of the composite without the magnetic field treatment (31.9 mW·cm −2 ). In contrast, the DMAFC using the CL-QPVA electrolyte generated only 22.4 mW·cm −2 . This research proved the surprising benefits of magnetic-field-assisted orientation of GO-Fe 3 O 4 in facilitating the ion conduction of a polymeric electrolyte.
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