Proton Conducting Nafion-Sulfonated Graphene Hybrid Membranes for Direct Methanol Fuel Cells with Reduced Methanol Crossover

Abstract

Sulfonic acid functionalized graphene (S-graphene) is explored as a potential inorganic filler as well as a solid acid proton conducting medium to realize a hybrid membrane with Nafion for a direct methanol fuel cell (DMFC). The simple, but effective, functionalization of graphene is performed by sulfonic acid containing aryl radicals to increase the number of sulfonate groups per unit volume of graphene domain. Nafion−S-graphene hybrid membranes increase compactness of ionic domains and enhanced proton conductivity while restricting the methanol crossover across the membrane. DMFCs with a Nafion−S-graphene (1 wt %) hybrid membrane deliver a peak power density of 118 mW cm −2 at a load current density of 450 mA cm −2 while operating at 70 °C under an ambient pressure. By contrast, operating under identical conditions, a peak power density of 54 mW cm −2 at a load current density of 241 mA cm −2 is obtained with the pristine recast Nafion membrane. The Nafion−S-graphene hybrid membranes are extremely beneficial and useful for DMFCs in addressing many critical problems associated with commercial Nafion membranes.

Sulfonated graphene oxide/Nafion composite membranes for high temperature and low humidity proton exchange membrane fuel cells

“…1,9 Besides, Naon membrane exhibits high hydrogen permeability denoted to as high hydrogen crossover from the anode to cathode through PEM as a result of concentration gradient. 10,11 Accordingly, researchers are developing modied PFSA membranes or designing alternative PEMs. Incorporation of inorganic llers, such as SiO 2 , ZrO 2 , CeO 2 , ZnO 2 , TiO 2 and zeolite nanoparticles and ZrO 2 , CeO 2 and TiO 2 nanotubes, into the Naon matrix has been demonstrated to result in composite PEMs with promising water uptake and consequently proton conductivity at high temperature and low humidity.…”

Toward improved mechanical strength, oxidative stability and proton conductivity of an aligned quadratic hybrid (SPEEK/FPAPB/Fe3O4-FGO) membrane for application in high temperature and low humidity fuel cells

“…Compared to SPF (3 nm), the SPFSGF-5 (unaligned) and SPFSGF-5 (aligned) membranes exhibited higher RMS roughness of 25 and 15 nm respectively, which may attributed to the crumbled structure of Fe 3 O 4 -FGO. 38 …”

Graphene Oxide Quantum Dots Exfoliated From Carbon Fibers by Microwave Irradiation: Two Photoluminescence Centers and Self‐Assembly Behavior

“…Graphene, a single layer of sp 2 ‐hybridized carbon atoms, has attracted extensive attention for its unique nanostructure and unusual properties, such as excellent electron mobility, high thermal conductivity, high specific surface area, excellent pliability, and high chemical stability. These properties enable graphene to become a promising material for applications of batteries, supercapacitors, field‐effect transistors, fuel cells, solar cells, sensors, and molecular sieving membranes . Graphene quantum dots (GQDs) and graphene oxide quantum dots (GOQDs), two members of the graphene family, possessing the advantage of graphene, are playing important roles in development and application of nanotechnology, such as bioimagings, fluorescent sensors, batteries, photocatalysts, light‐emitting diodes, photovoltaic devices, and drug delivery .…”