Reorientation of Magnetic Graphene Oxide Nanosheets in Crosslinked Quaternized Polyvinyl Alcohol as Effective Solid Electrolyte

Abstract

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.

Enhanced alkaline stability and performance of alkali‐doped quaternized poly(vinyl alcohol) membranes for passive direct ethanol fuel cell

“…The alkaline uptake has influenced the single cell performance because of the operation condition of fuel (ethanol in KOH solution) . Besides, to reveal the capacity of ionic conductivity under the actual operations, the KOH uptake result has become a primary indicator because of the function of KOH, which reacts as an ionic carrier for the anion transport in the matrix polymer . However, the excessive in alkali uptake will leads in membrane swelling phenomena as observed in QPVA membrane.…”

“…Alkaline uptakes for QPVA, QPVA/KOH2, QPVA/KOH4, QPVA/KOH6, and QPVA/KOH8 membrane were 95%, 54%, 62%, 58%, and 52%, respectively, as listed in Table . The alkaline uptake has influenced the single cell performance because of the operation condition of fuel (ethanol in KOH solution) . Besides, to reveal the capacity of ionic conductivity under the actual operations, the KOH uptake result has become a primary indicator because of the function of KOH, which reacts as an ionic carrier for the anion transport in the matrix polymer .…”

Surfactant-Assisted Perovskite Nanofillers Incorporated in Quaternized Poly (Vinyl Alcohol) Composite Membrane as an Effective Hydroxide-Conducting Electrolyte

“…Moreover, we used low catalyst loadings in the anode (2 mg cm −1 ) and cathode (1 mg cm −1 ), which provided the advantage of low-cost DAMFC manufacturing. To our best knowledge, this Pmax output is the highest value of DAMFCs recorded [7,8,[17][18][19][20][21]23,24,63,[74][75][76]. Based on the above tests, the optimal operating condition was fed with 4 M of methanol solution, cell temperature of 60 • C, and the use of the QPVA/CTAB-coated LaFeO 3 composite electrolyte.…”

“…These nanocomposite membranes deliver noteworthy advantages over traditional pure polymeric membranes due to their higher ionic conductivity, suppressed permeability, and improved power densities [23,24]. Among the different nanofillers, perovskite-type oxides (with a chemical structure of ABO 3 ) have recently attracted much attention in energy-based and conversion applications such as solar cells, photocatalysis, electrode catalysis, lithium-ion batteries, supercapacitors, and fuel cells [25,26].…”

Experimental and One-Dimensional Mathematical Modeling of Different Operating Parameters in Direct Formic Acid Fuel Cells

“…The electrolyte membrane was immersed in DI water and formic acid solutions at different temperatures for 3 h and placed between two stainless steel electrode rods in a T-tube glass, as illustrated in our previous report [38][39][40]. The membrane was maintained at 98% relative humidity at a fixed temperature for the proton conductivity analysis.…”