Fabrication of nanocomposite membrane via combined electrospinning and casting technique for direct methanol fuel cell

In the past decades, the emerging of nanotechnology has brought to the introduction of electrospinning process in polymer electrolyte nanocomposite membrane due to its specialty in providing a very large specific surface area which contributed by a small size of fillers and an outstanding nanovoids interconnectivity between the fillers. The objective of this study was to fabricate and characterize sulfonated poly (ether ether ketone) (SPEEK) nanocomposite membrane consist of electrospun Cloisite15A® (e-spun CL) for direct methanol fuel cell (DMFC) applications. Poly (ether ether ketone) polymer was sulfonated by sulfuric acid to obtain degree of sulfonation of 63%. SPEEK63/e-spun CL nanofibers were fabricated via electrospinning process in which SPEEK63 was used as carrier polymer while SPEEK63/e-spun CL nanocomposite membrane was obtained by casting method. Characterizations on physical, morphological and thermal properties of SPEEK63/e-spun CL were conducted and compared to SPEEK nanocomposite membrane with 2.5wt.% Cloisite15A® and 5.0wt.% triaminopyrimidine (SPEEK63/2.5CL/5.0TAP). Scanning electron microscopy (SEM) showed that Cloisite15A® was well electrospun with the nanofiber diameter ranging from 62.5 to 375 nm. Moreover, field emission scanning electron microscopy (FESEM) revealed that Cloisite15A® particles at nanometer range were uniformly distributed and 66% smaller than in SPEEK63/2.5CL/5.0TAP. In addition, x-ray diffraction proved that the dispersion state of Cloisite15A® fell into intercalated phase. A very small amount of Cloisite15A® (0.05wt.%) in SPEEK63/e-spun CL had successfully enhanced the proton conductivity up to 50% whereas, methanol permeability value was unfortunately 27 times higher than SPEEK63/2.5CL/5.0TAP. Proton conductivity and methanol permeability of SPEEK63/e-spun CL were 24.49 x 10-3 Scm-1 and 3.74 x 10-7 cms-1, respectively. Even though this study contributed to a selectivity of 95% lower than SPEEK63/2.5CL/5.0TAP, the electrospinning process had shown a promising technique to further reduce the original size of Cloisite15A® particles from mixed size (µm and nm) to nanometer size as well as by fine tuning the dispersion of Cloisite15A® can enhance SPEEK63/e-spun CL performance in DMFC applications

Fabrication of nanocomposite membrane via combined electrospinning and casting technique for direct methanol fuel cell

Emergence of nanotechnology has resulted in the introduction of the electrospinning process in fabricating and characterising the polymer electrolyte membrane from the sulfonated poly (ether ether ketone) (SPEEK) nanocomposite membrane comprised of electrospun Cloisite15A® (e-spun CL) for direct methanol fuel cell (DMFC). Poly (ether ether ketone) polymer is sulfonated up to 63% by sulfuric acid. SPEEK63/e-spun CL nanofibers were fabricated via electrospinning in which SPEEK63 was used as carrier polymer while the SPEEK63/e-spun CL nanocomposite membrane was obtained by the casting method. Characterizations on physical, morphological and thermal properties of SPEEK63/e-spun CL were conducted and compared to the SPEEK membrane fabricated by casting simple mixing 2.5wt.% Cloisite15A® and 5.0wt.% triaminopyrimidine solution (SPEEK63/2.5CL/5.0TAP). Scanning electron microscopy (SEM) showed well electrospun Cloisite15A® with an average diameter nanofiber around 187.4 nm. Moreover, field emission scanning electron microscopy (FESEM) revealed that Cloisite15A® particles at a nanometer range were uniformly distributed and 66% smaller than those in SPEEK63/2.5CL/5.0TAP. Furthermore, x-ray diffraction proved that the dispersion state of Cloisite15A® fell into an intercalated phase. A very small amount of Cloisite15A® (0.05wt.%) in SPEEK63/e-spun CL successfully enhanced the proton conductivity up to 50%, whereas, unfortunately the methanol permeability value was 27 times higher than SPEEK63/2.5CL/5.0TAP. Proton conductivity and methanol permeability of SPEEK63/e-spun CL were 24.49 x 10-3 Scm-1 and 3.74 x 10-7 cms-1, respectively. Even though this study contributed to 95% selectivity lower than SPEEK63/2.5CL/5.0TAP, electrospinning showed a promising technique to further reduce original sized Cloisite15A® particles from mixed size (μm and nm) to nanometer sized. In addition, by fine tuning, the dispersion of Cloisite15A® enhances the SPEEK63/e-spun CL performance in DMFC

Performance of Polymer Electrolyte Membrane for Direct Methanol Fuel Cell Application: Perspective on Morphological Structure

Membrane morphology plays a great role in determining the performance of polymer electrolyte membranes (PEMs), especially for direct methanol fuel cell (DMFC) applications. Membrane morphology can be divided into two types, which are dense and porous structures. Membrane fabrication methods have different configurations, including dense, thin and thick, layered, sandwiched and pore-filling membranes. All these types of membranes possess the same densely packed structural morphology, which limits the transportation of protons, even at a low methanol crossover. This paper summarizes our work on the development of PEMs with various structures and architecture that can affect the membrane’s performance, in terms of microstructures and morphologies, for potential applications in DMFCs. An understanding of the transport behavior of protons and methanol within the pores’ limits could give some perspective in the delivery of new porous electrolyte membranes for DMFC applications

Polymer based membrane electrospun fiber in fuel cell application: a short review

Currently, the need of renewable energy becomes crucial due to the problem arising via fossil fuels usage which contributes to the environmental issues. Among the type of existing renewable energy, fuel cells is the most promising renewable energy sources since the energy can be directly converted from combustible of fuel. The proton exchange membrane (PEM) is the heart of the fuel cells system. The research and development on proton electrolyte membrane is keep burgeoned. Even though the studies of the electrolyte nanocomposite membrane for fuel cell application are quite various but only a few studies focused on the effect of electrospun nanocomposite membrane on the performance of proton electrolyte membrane. This review is focusing on the electrospinning process for the preparation of electrospun fiber membrane. This review is concentrates on polymer based membrane electrospun nanofiber and their influence on proton conductivity as well as on fuel crossover barrier properties. The proton conductivity and fuel crossover can be improved by fully exfoliated structure of nanocomposite electrolyte membrane via electropinning process and thus the membrane can be an alternative PEM for DMFC application

Functionalization of polymeric materials as a high performance membrane for direct methanol fuel cell: a review

A coherent review on the advanced proton exchange membranes (PEMs) for direct methanol fuel cell (DMFC) application and the future direction in the development of a high performance polymeric membrane for DMFC were discussed in this paper. PEMs have a profound influence on performance of DMFC. The PEMs are categorized into five groups which are partially fluorinated, perfluorinated ionomers, acid-base complexes, non-fluorinated ionomers, hydro carbon and aromatic polymers. Many researchers have investigated the functionalization methods on the PEMs to solve methanol crossover problem while obtaining low electronic conductivity, high proton conductivity, low electro osmotic drag coefficient, high mechanical properties and good chemical and thermal stability. Including in this review, fabrication of PEM using electrospinning process coupled with the promising functionalized polymeric materials which were known to be the most important initiatives at present in order to further expand the full potential of DMFC performan

Synthesis and characterization of conductive polymer coated graphitic carbon nitride embedded sulfonated poly (ether ether ketone) membranes for direct methanol fuel cell applications

Direct methanol fuel cell (DMFC) is a sustainable energy conversion device that is known for its advantages in terms of portability as well as can be stored and transported safely. Functionalized nanostructured materials have been used in proton exchange membrane (PEM) for DMFC applications to enhance the proton conductivity and suppress the methanol permeability. In this study, conductive polyaniline deposited oxidized graphitic carbon nitride (PANI-O-g-C3N4) was incorporated in sulfonated poly (ether ether ketone) (SPEEK) membrane for DMFC applications. The performances of graphitic carbon nitride (g-C3N4) and oxidized graphitic carbon nitride (O-g-C3N4) on SPEEK PEM were also assessed and compared. The morphological and X-ray diffraction analysis indicated that the structure and crystallinity were altered with the deposition of PANI on g-C3N4. The scanning electron microscopy and topography analysis revealed that the existence of g-C3N4 and functionalized g-C3N4 were clearly seen on the surface of the SPEEK membrane. Water uptake capacity and ion exchange capacity were significantly improved in the functionalized g-C3N4-modified SPEEK membrane (O-g-C3N4/SPEEK and PANI-O-g-C3N4/SPEEK). The lower methanol permeability and higher proton conductivity of 3.71 × 10-7 cm-2 S-1 and 5.34 × 10-3 S cm-1 were recorded by 0.1 wt% PANI-O-g-C3N4 incorporated SPEEK membrane. Functionalized g-C3N4-modified SPEEK membrane also exhibited higher oxidative stability. The performance of the PANI-O-g-C3N4 incorporated SPEEK membrane in DMFC application highlights its potential as a superior nanofiller for the modification of PEM

Metal-Organic Frameworks for Wastewater Decontamination: Discovering Intellectual Structure and Research Trends

Due to their simple synthesis method and excellent properties, such as superior adsorption and regeneration capabilities, with a large surface area and tunable pores, metal-organic frameworks (MOFs) have emerged as a suitable option for wastewater treatment. Although an exponential growth in MOF literature has been observed in recent years, conducting a quantitative literature analysis of MOF application in wastewater treatment is a novelty. To fill this gap, a total of 1187 relevant publications were extracted from the Web of Science, published during the last 50 years, and analyzed using bibliometric and content analysis techniques. A bibliometric analysis was conducted to reveal growing publication trends, leading journals, prolific countries, and organizations; whereas, a content analysis was used to highlight key research themes and hot topics in this field. The analyses revealed that there is a strong international collaboration among authors, countries, and organizations. Chemical Engineering Journal, Journal of Hazardous Materials, and Journal of Environmental Chemical Engineering are the most prolific journals in this field. Furthermore, the use of MOFs for removing antibiotics from wastewater was identified as a recent hot topic. In addition, performance enhancements of MOFs, in terms of a higher adsorption capacity and water stability, were identified as topics of great interest. To cater to these issues, the application of graphene, graphene oxides, nanoparticles, and quantum dots was also observed in the research fronts in this field

Fabricanon of as-spun SPEEK as a function of degree of sulfonation

The purpose of this study was 10 determine the effect of degree of sulfonation (DS) on electrospun sulfonated poly (ether ether ketone) (SPEEK) fiber. SPEEK was prepared via sulfonation process by sulfonating native poly (ether ether ketone) (PEEK) with concentrated sulfuric acid (95-97%). The prepared SPEEKs polymer was characterized for their OS via hydrogen-nuclear magnetic resonance (WNMR) spectroscopy. The electrospinning process was taking placed in developing an eleetrospun SPEEK nanofibers mat and scanning electron microscopy (SEM) was used .to observe the morphological structural of the electrospun SPEEK nanofibers. SPEEK with different DS at50%, 58%, 68% and 80% was prepared in this /study.Ir was observed that the diameter of the fiber decreased as the DS increased aithe same operating parameters (flow rate and distance from needle tip to the collector), From SEM analysis, it was found that the diameter of the SPEEK nanofiber with the DS of 50('/0, 58%, 68% and 80% was 20him, 103.8nm, 68.9nin aDd 68nrn, respectively. Eventhough the obtained as-spun nanofiber from SPEEK at DS of 500/0 showed better appearance in its nanofiber mat form but the nanofiber spun at higher DS exhibited favorable lfiber 'structure due to its smaller size in diameter.In conclusion, the higher the DS of the SPEEK the smaller the diameter of the obtained fibers was

A Review on the fabrication of electrospun polymer electrolyte membrane for direct methanol fuel cell

Proton exchange membrane (PEM) is an electrolyte which behaves as important indicator for fuel cell’s performance. Research and development (R&D) on fabrication of desirable PEM have burgeoned year by year, especially for direct methanol fuel cell (DMFC). However, most of the R&Ds only focus on the parent polymer electrolyte rather than polymer inorganic composites. This might be due to the difficulties faced in producing good dispersion of inorganic filler within the polymer matrix, which would consequently reduce the DMFC’s performance. Electrospinning is a promising technique to cater for this arising problem owing to its more widespread dispersion of inorganic filler within the polymer matrix, which can reduce the size of the filler up to nanoscale. There has been a huge development on fabricating electrolyte nanocomposite membrane, regardless of the effect of electrospun nanocomposite membrane on the fuel cell’s performance. In this present paper, issues regarding the R&D on electrospun sulfonated poly (ether ether ketone) (SPEEK)/inorganic nanocomposite fiber are addressed

Porous polyether sulfone for direct methanol fuel cell applications: structural analysis

Porous poly ether sulfone (PES) membranes were prepared using two different solvents which were N-methyl-2-pyrrolidone and dimethylacetamide (DMAc) via dry/wet non-solvent phase inversion (NIPS) techniques. PES with the compositions of 18 wt% is prepared for each dope solution. During the membrane casting process, 0 to 5 minutes delay prior to immersion in coagulant bath is set in order to allow solvent evaporation to take place. Water is used as the non-solvent for solvent exchange process. The prepared membranes are characterised based on their morphological aspect using scanning electron microscopy towards the effect of solvent evaporation time and solution viscosity. The changes in proton conductivity, methanol permeability, water uptake and hydrophilicity/hydrophobicity behaviours are also studied. Conclusively, the 18 wt% PES membranes prepared with DMAc as solvent at 3 minutes solvent evaporation time exhibited desirable pore size for proton conduction (0.04 × 10−3 Scm−1) and methanol resistant effect that consequently contribute to considerably low methanol permeability rate at 0.06 × 10−7 cm2 s−1 which could elevate the direct methanol fuel cell performance