Direct Methanol Fuel Cell Applications Research Articles

Anatase titania coated CNTs and sodium lignin sulfonate doped chitosan proton exchange membrane for DMFC application

Anatase titania coated CNTs (TCNTs) and sodium lignin sulfonate (SLS) were introduced to chitosan membrane to improve the conductivity based on extra proton transfer channels built by TCNTs and sulfonate groups supplied by SLS. Water uptake, mechanical properties, oxidation stability and methanol-rejecting property of composite membranes were characterized. The results show that TCNTs and SLS doped membranes have enhanced conductivity and the sample with 5% TCNTs and 2% SLS doped (CS/TCNT-5/SLS-2) achieved a conductivity of 0.0367 S cm−1 at room temperature and 0.0647 S cm−1 at 60 °C, which is much higher than pure chitosan membrane. Moreover, with TCNTs incorporation, the mechanical properties, oxidation stability and methanol-rejecting property also improved. Overall, selectivity of CS/TCNT-5/SLS-2 sample achieved 28.2 × 104 S s cm−3 which is much higher than 3.8 × 104 S s cm−3 of pure chitosan membrane. Thus, with enhanced properties, chitosan composite membrane could be promising as proton exchange membrane (PEM) in the use of direct methanol fuel cell (DMFC).

Effect of nano-size of functionalized silica on overall performance of swelling-filling modified Nafion membrane for direct methanol fuel cell application

A non-destructive swelling-filling (SF) strategy is applied for inorganic modification on Nafion by using functionalized silica (F-silica) nanoparticles as fillers. With the facilely prepared F-silica gel as SF treating agent, the mono-dispersed F-silica nanoparticles can in-situ insert into the Nafion membrane and tightly anchor on the Nafion chains through the hydrogen bonding interaction between the oxygen containing groups on F-silica fillers and –SO3H group on Nafion chains. The F-silica nanoparticles act as bi-functional fillers in the modified Nafion membrane to improve proton conductive and methanol-permeation resistive performances simultaneously. 100% enhanced proton/methanol selectivity therefore leads to a more than 30% improved direct methanol fuel cell (DMFC) performance in terms of power output. By considering the great mechanical, thermal and oxidative stabilities comprehensively, the F-silica-Nafion membranes exhibit promising application potential for high-energy DMFC application.

Surface modified multi‐walled carbon nanotubes and Nafion nanocomposite membranes for use in fuel cell applications

The preparation and characterization of the nanocomposite polyelectrolyte membranes, based on Nafion, sulfonated multi‐walled carbon nanotubes (MWCNT‐SO3H) and imidazole modified multi‐walled carbon nanotubes (MWCNT‐Im), for direct methanol fuel cell applications is described. The results showed that the modification of multi‐walled carbon nanotubes (MWCNT) with proton‐conducting groups (sulfonic acid groups or imidazole groups) could enhance the proton conductivity of the nanocomposite membranes in comparison to Nafion 117. Regarding the interactions between the protonated imidazole groups, grafted on the surface of MWCNT, and the negatively charged sulfonic acid groups of Nafion, new electrostatic interactions can be formed in the interface of the Nafion and MWCNT‐Im, which result in both lower methanol permeability and higher proton conductivity. The physical characteristics of these manufactured nanocomposite membranes were investigated by thermogravimetric analysis, differential scanning calorimetry, Fourier transform infrared spectroscopy, water uptake, methanol permeability, and ion exchange capacity, as well as proton conductivity. The Nafion/MWCNT‐Im membranes showed the higher proton conductivity, lower methanol permeability, and, as a consequence, a higher selectivity parameter in comparison to the neat Nafion or Nafion membrane containing MWCNT‐SO3H or ─OH functionalized multi‐walled carbon nanotubes (MWCNT‐OH) membranes. The obtained results indicated that the Nafion/MWCNT‐Im membranes could be used as efficient polyelectrolyte membranes for direct methanol fuel cell applications.

Improvement in the mechanical properties, proton conductivity, and methanol resistance of highly branched sulfonated poly(arylene ether)/graphene oxide grafted with flexible alkylsulfonated side chains nanocomposite membranes

Sulfonated polymer/graphene oxide (GO) nanocomposites exhibit excellent properties as proton exchange membranes. However, few investigations on highly branched sulfonated poly(arylene ether)s (HBSPE)/GO nanocomposites as proton exchange membranes are reported. In order to obtain HBSPE-based nanocomposite membranes with better dispersibility and properties, a novel GO containing flexible alkylsulfonated side chains (SGO) is designed and prepared for the first time in this work. The HBSPE/SGO nanocomposite membranes with excellent dispersibility are successfully prepared. The properties of these membranes, including the mechanical properties, ion-exchange capacity, water uptake, proton conductivity, and methanol resistance, are characterized. The nanocomposite membranes exhibit higher tensile strength (32.67 MPa), higher proton conductivity (0.39 S cm−1 at 80 °C) and lower methanol permeability (4.89 × 10−7 cm2 s−1) than the pristine membrane. The nanocomposite membranes also achieve a higher maximum power density (82.36 mW cm−2) than the pristine membrane (67.85 mW cm−2) in single-cell direct methanol fuel cell (DMFC) tests, demonstrating their considerable potential for applications in DMFCs.

Self-crosslinked organic-inorganic nanocomposite membranes with good methanol barrier for direct methanol fuel cell applications

The organic-inorganic latex particles with sulfonic acid groups and core-shell structure are successfully obtained and then are heated to fabricate the self-crosslinked organic-inorganic nanocomposite membranes. Fourier transform infrared (FTIR) spectra confirm the chemical structure of membranes. The effects of inorganic component on the performances of nanocomposite membranes are investigated extensively. TGA analyses show that the membrane materials possess excellent thermal stability and 5% weight loss temperature increase with increasing SiO2 content. Solvent absorption measurement suggests the membranes are less permeable to methanol than water. The obtained membranes show conductivity values above 10−2Scm−1. More importantly, all the membrane materials exhibit more excellent methanol barrier and higher selectivity compared with Nafion® 117, demonstrating that those membranes could be a potential candidate as proton exchange membranes for future direct methanol fuel cells.

Role of structural modifications of montmorillonite, electrical properties effect, physical behavior of nanocomposite proton conducting membranes for direct methanol fuel cell applications

AbstractProton exchange membranes have been synthesized from polyimide (PI) doped with different contents of montmorillonite (MMT) which was obtained by solution casting technique. The enhancement of conductivity was achieved through modification with the MMT. Prepared membranes were systematically characterized in terms of ion exchange capacity, water uptake, methanol uptake, swelling behavior and proton conductivity. Fourier transform infrared spectroscopy and X-ray diffraction measurements were used to confirm the structures of the PI/MMT composite electrolyte membranes. SEM surface morphological images of the composite membranes showed that the MMT nanoclay particles were dispersed uniformly within the membrane what was also reflected in XRD results which indicated a good compatibility of MMT particles with the polymer complex. The TGA spectra showed that the thermal stability of the membrane was reduced by adding MMT into the polymer network. The prepared membrane with 10 wt.% of modified MMT exhibited the highest proton conductivity value of 7.06 × 10-2S·cm-1at 70 °C. These results imply the potential application of the PI/MMT composite membranes as improved PEMs for DMFC applications.

Effect of Temperature on Sulfonated Poly (Ether Ether Ketone) Blended with Charged Surface Modifying Macromolecule Membrane for DMFCs

The purpose of this research was to determine the behavior of modified sulfonated poly (ether ether ketone) (SPEEK) with degree of sulfonation (DS) 68% blended by charged surface modifying macromolecule (cSMM) at different operating temperatures (room to 80°C) for direct methanol fuel cell application. The fabricated SPEEK (68)/cSMM membrane was compared with SPEEK (68) and Nafion112 membranes in terms of water uptake, proton conductivity, and methanol permeability at relatively high temperatures. The water uptake of SPEEK (68)/ cSMM was higher than that of SPEEK (68) and Nafion112 over the temperature ranges studied; however it was dissolved at 80°C. Proton conductivity of SPEEK (68)/cSMM showed improvement compared to SPEEK (68) at temperature range, but still lower than Nafion112, moreover methanol permeability behavior of fabricated membrane was lower at high temperatures as compared to that of SPEEK and Nafion112 and better overall performance was allocated to the fabricated membrane at 60°C.These results indicate that SPEEK (68)/cSMM membrane is promising to be used as a proton exchange membrane in direct methanol fuel cell.

Preparation and Characterization of High Methanol Resistance Sulfonated Poly(ether ether ketone) Membrane for DMFC Application

High methanol resistance sulfonated poly(ether ether ketone) (SPEEK) membranes have been prepared and characterized as a potential proton exchange membrane for direct methanol fuel cell. The sulfonation process was conducted at room temperature to produce SPEEK with 60% degree of sulfonation (DS). The produced membranes were then characterized by evaluating the swelling behavior in terms of water uptake, swelling ratios and methanol sorption as a function of temperature and reaction time. Interestingly, it was observed that the methanol uptake value of SPEEK membrane was lower as compared to the water uptake value as much as 80%. This characteristic showed that SPEEK membrane possesses good resistance towards methanol which is a crucial property requires for direct methanol fuel cell (DMFC) application.

Chitosan/partially sulfonated poly(vinylidene fluoride) blends as polymer electrolyte membranes for direct methanol fuel cell applications

A novel proton exchange membranes composed of a blend of chitosan and sulfonated polyvinylidene fluoride (SPVDF) was prepared by solution casting technique. The PVDF was sulfonated using direct sulfonation method with sulfonation degree of 6.1%. The membranes with different fractions of SPVDF were prepared and 10 wt% SPVDF exhibits the best performance in terms of ion exchange capacity, conductivity, water uptake and membrane selectivity. The prepared blend membranes show excellent combination of thermal stability, mechanical properties, dimensional stability and methanol barrier properties. Chitosan (CS)-SPVDF-90/10 membrane shows the highest proton conductivity of 2.85 × 10−2 S cm−1 at 90 °C.

Enhanced performance of sulfonated poly (ether ether ketone) membranes by blending fully aromatic polyamide for practical application in direct methanol fuel cells (DMFCs)

The high dimensional swelling has been considered as one of the most important issues for obstructing sulfonated poly (ether ether ketone) (SPEEK) membrane with high IEC value as an excellent performance proton exchange membrane (PEM) for direct methanol fuel cell (DMFC) application. Here, we present a facile way to overcome the issue via blending the fully aromatic polyamide (fa-PA) into SPEEK membrane. The Influence of the fa-PA on the key properties of the fabricated fa-PA/SPEEK composite membranes (fa-PASPs) was systematically investigated. As the promising dimensional stability of the fa-PA, the fa-PASPs display excellent dimensional stability both in water and methanol aqueous solution. In addition, the fa-PASPs exhibit uniform and smooth morphology due to the same fully aromatic polyamide backbones as SPEEK and strong hydrogen bonding interactions between fa-PA and SPEEK with significantly reduced methanol crossover. The remarkable cell performance at high methanol concentration up to neat methanol was significantly obtained, suggesting that the prepared fa-PASPs are suitable for using as PEMs in direct methanol fuel cells application.

Enhanced Electrochemical Performance of Stable SPES/SPANI Composite Polymer Electrolyte Membranes by Enriched Ionic Nanochannels.

Herein, we present the results of sulfonated polyaniline (SPANI) and sulfonated poly(ether sulfone) (SPES) composite polymer electrolyte membranes. The membranes are established for high-temperature proton conductivity and methanol permeability to render their applicability. Composite membranes have been prepared by modifying the SPES matrix with different concentrations of SPANI (e.g., 1, 2, 5, 10, and 20 wt %). Structural and thermomechanical characterizations have been performed using the transmission electron microscopy, differential scanning calorimetry, thermogravimetric analysis, and dynamic mechanical analyzer techniques. Physicochemical and electrochemical properties have been evaluated by water uptake, ion-exchange capacity, dimensional stability, and proton conductivity. Methanol permeability experiment was carried out to analyze the compatibility of prepared membranes toward direct methanol fuel cell application and found the lowest methanol permeability for PAS-5. Also, the membranes reveal excellent thermal, mechanical, and physicochemical properties for their application toward high-temperature electromembrane processes.

Property Enhancement Effects of Side-Chain-Type Naphthalene-Based Sulfonated Poly(arylene ether ketone) on Nafion Composite Membranes for Direct Methanol Fuel Cells.

Nafion/SNPAEK-x composite membranes were prepared by blending raw Nafion and synthesized side-chain-type naphthalene-based sulfonated poly(arylene ether ketone) with a sulfonation degree of 1.35 (SNPAEK-1.35). The incorporation of SNPAEK-1.35 polymer with ion exchange capacity (IEC) of 2.01 mequiv·g-1 into a Nafion matrix has the property enhancement effects, such as increasing IECs, improving proton conductivity, enhancing mechanical properties, reducing methanol crossover, and improving single cell performance of Nafion. Morphology studies show that Nafion/SNPAEK-x composite membranes exhibit a well-defined microphase separation structure depending on the contents of SNPAEK-1.35 polymer. Among them, Nafion/SNPAEK-7.5% with a bicontinuous morphology exhibits the best comprehensive properties. For example, it shows the highest proton conductivities of 0.092 S cm-1 at 25 °C and 0.163 S cm-1 at 80 °C, which are higher than those of recast Nafion with 0.073 S cm-1 at 25 °C and 0.133 S cm-1 at 80 °C, respectively. Nafion/SNPAEK-5.0% and Nafion/SNPAEK-7.5% membranes display an open circuit voltage of 0.77 V and a maximum power density of 47 mW cm-2 at 80 °C, which are much higher than those of recast Nafion of 0.63 V and 24 mW cm-2 under the same conditions. Nafion/SNPAEK-5.0% membrane also has comparable tensile strength (12.7 MPa) to recast Nafion (13.7 MPa), and higher Young's modulus (330 MPa) than that of recast Nafion (240 MPa). By combining their high proton conductivities, comparable mechanical properties, and good single cell performance, Nafion/SNPAEK-x composite membranes have the potential to be polymer electrolyte materials for direct methanol fuel cell applications.

Polyelectrolyte Nanocomposite Membranes with Imidazole-Functionalized Multi-Walled Carbon Nanotubes for Use in Fuel Cell Applications

ABSTRACTThe preparation and characterization of a new type of nanocomposite polyelectrolyte membrane (PEM), based on Nafion® and imidazole modified multi-walled carbon nanotubes (MWCNT-Im), for direct methanol fuel cell (DMFC) applications is described. Related to the interactions between the protonated imidazole groups, grafted on the surface of multi-walled carbon nanotubes (MWCNT), and the negatively charged sulfonic acid groups of Nafion®, new electrostatic interactions can be formed in the interface of the Nafion® and MWCNT-Im which result in both lower methanol permeability and also higher proton conductivity. The physical characteristics of these manufactured nanocomposite membranes were investigated by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), water uptake, methanol permeability and ion exchange capacity, as well as proton conductivity. The Nafion®/MWCNT-Im membranes showed higher proton conductivity, lower methanol permeability and, as a consequence, a higher selectivity parameter in comparison to neat Nafion® or Nafion® containing –OH functionalized multi-walled carbon nanotubes (MWCNT-OH) membranes. The obtained results indicated that the Nafion®/MWCNT-Im membranes could be utilized as efficient polyelectrolyte membranes for direct methanol fuel cell applications.

A superhydrophobic bromomethylated poly(phenylene oxide) as a multifunctional polymer filler in SPEEK membrane towards neat methanol operation of direct methanol fuel cells

Development of novel proton exchange membrane (PEM) with the aim toward neat methanol operation of direct methanol fuel cell (DMFC) has attracted increasing attention. Proton exchange membrane technology with remarkably low methanol permeability has been considered as one of the most facile ways to approach this target. Here, sulfonated poly(ether ether ketone) (SPEEK) membrane was modified by blending with superhydrophobic bromomethylated poly(phenylene oxide) (BPPO). The fabricated SPEEK/BPPO membranes possess obviously low methanol permeability, which is attributed to the formed interrupted methanol transport channels arising from the combined properties of the hydrophobic BPPO polymeric backbone, the formed spherical BPPO obstacles and the cross-linking networks derived from the Friedel-Craft reaction between bromobenzyl groups and nucleophilic phenyl rings. Therefore, the SPEEK/BPPO membrane DMFC demonstrates a much higher cell performance both at low methanol concentration and high methanol concentration than the Nafion 117 DMFC. In particular, the actual value of the maximum power density at high methanol concentration of 20M suggests that the SPEEK/BPPO membranes can be considered as a desirable candidate for potential application in high methanol concentration DMFCs.

Development of dense void-free electrospun SPEEK-Cloisite15A membrane for direct methanol fuel cell application: Optimization using response surface methodology

Response surface methodology (RSM) was utilized to design the experiments at the settings of solution concentration, voltage and the collector distance. It also imparted the evaluation of the significance of each parameter on the resultant physico chemicals (proton conductivity, methanol permeability and water uptake). The investigations were carried out in the two-variable process domains of several collector distances as applied voltage and the solution concentration were varied at a fixed polymer molecular weight. The result showed that all three factors were found statistically significant in the production of void free electrospun SPEEK/Cloisite membrane. All responses were correlated to these variables by using a second order polynomial function. The optimum condition for void free electrospun SPEEK/cloisite was at 0.17 wt% concentration with applied voltage of 22.15 kV and 18.83 cm distance from needle tip to screen collector.

Synthesis and applications of ordered and disordered mesoporous zeolites: Present and future prospective

Zeolites are microporous aluminosilicates that are used extensively for a wide variety of industrial applications. Applications of microporous zeolites are limited to transformations of small molecules due to the pore diffusion limitation imposed by the microporous network structure. In order to overcome this limitation, zeolites with inter-/intra-crystalline mesopores are generally preferred. This review article presents the details of various strategies for the preparation of mesoporous zeolites with inter-/intra-crystalline mesopores. A wide range of soft templates and additives is described in details for their use in the synthesis of mesoporous ZSM-5 and Beta zeolites. A brief report on the applications of mesoporous zeolites in various acid catalyzed reactions, involving large organic molecules, is provided in this article. Another important feature of this article is that it summarizes the applications of mesoporous zeolites in the electrochemical detection of various physiologically important biomolecules and organic/inorganic water pollutants. Further, the role of mesoporous zeolites based electrode materials for direct methanol fuel cell application is presented. Finally, the potential role of mesoporous zeolites in the field of biomedical engineering, particularly as a bone implant material, is summarized.

Functionalized and Electrospun Polymeric Materials as High-Performance Membranes for Direct Methanol Fuel Cell: A Review

Proton exchange membranes (PEM) for a direct methanol fuel cell (DMFC) have main drawbacks which are methanol permeability, reduced proton conductivity and the cost of the membrane. This paper reviews different polymeric materials such as fluorinated, non-fluorinated, acid-base complex, and composite membranes for DMFC. Currently, nonfluorinated membranes gain a lot of attention due to their low cost. Many researchers have developed functionalization methods for non-fluorinated polymer electrolyte membranes for DMFC application to reduce the methanol crossover. Finally, this review presents the Electrospinning technique and its parameter for fabrication of PEM with functionalized polymeric materials by using electrospinning to solve the proton conductivity and methanol permeability problem. The last part of the paper describes the current studies and future direction of PEM for DMFC.

Enhancement of Hybrid SPEEK Based Polymer–Cyclodextrin-Silica Inorganic Membrane for Direct Methanol Fuel Cell Application

Direct methanol fuel cell (DMFC) is one of several types of fuel cells that use proton exchange membrane (PEM) as a liaison between the reaction at the cathode and anode. Polyether-ether ketone (PEEK) is one of the aromatic polymer that can be applied in DMFC because of its characteristics that are resistant to DMFC environment. The polymer is also quite easy in the sulfonation process using concentrated sulfuric acid. However the role of polyether-ether ketone as DMFC membrane material is still lack of advantage due to its low conductivity and therefore the modification is required to increase the value of proton conductivity of the membrane. The purpose of this experiment is to modify the membrane (sPEEK) with the addition of cyclodextrins-silica, additive variation charge of 2%, 6% and 10%, time and temperature were fixed at 4 hours and 65oC. The results showed the best results of membrane sPEEK was obtained at the addition of -cyclodextrin -silica 10% with the membrane characteristics of ion exchange capacity of 2.19 meq / g polymer, the degree of sulfonation of 81%, methanol permeability of 3.09 x 10-9 cm2 / s and water uptake membrane of 64%.Article History: Received January 18th 2017; Received in revised form April 21st 2017; Accepted June 22nd 2017; Available onlineHow to Cite This Article: Kusworo, T.D., Hakim, M.F. and Hadiyanto, H. (2017) Enhancement of Hybrid SPEEK Based Polymer–Cyclodextrin-Silica Inorganic Membrane for Direct Methanol Fuel Cell Application. International Journal of Renewable Energy Development, 6(2), 165-170.https://doi.org/10.14710/ijred.6.2.165-170

Enhancement of Hybrid SPEEK Based Polymer–Cyclodextrin-Silica Inorganic Membrane for Direct Methanol Fuel Cell Application

Direct methanol fuel cell (DMFC) is one of several types of fuel cells that use proton exchange membrane (PEM) as a liaison between the reaction at the cathode and anode. Polyether-ether ketone (PEEK) is one of the aromatic polymer that can be applied in DMFC because of its characteristics that are resistant to DMFC environment. The polymer is also quite easy in the sulfonation process using concentrated sulfuric acid. However the role of polyether-ether ketone as DMFC membrane material is still lack of advantage due to its low conductivity and therefore the modification is required to increase the value of proton conductivity of the membrane. The purpose of this experiment is to modify the membrane (sPEEK) with the addition of cyclodextrins-silica, additive variation charge of 2%, 6% and 10%, time and temperature were fixed at 4 hours and 65oC. The results showed the best results of membrane sPEEK was obtained at the addition of -cyclodextrin -silica 10% with the membrane characteristics of ion exchange capacity of 2.19 meq / g polymer, the degree of sulfonation of 81%, methanol permeability of 3.09 x 10-9 cm2 / s and water uptake membrane of 64%. Keywords: Direct Methanol Fuel Cell, Poly(ether ether ketone), cyclodextrin-silica, sulfonation, ionic conductivity.Article History: Received January 18th 2017; Received in revised form April 21st 2017; Accepted June 22nd 2017; Available onlineHow to Cite This Article: Kusworo, T.D., Hakim, M.F. and Hadiyanto, H. (2017) Enhancement of Hybrid SPEEK Based Polymer–Cyclodextrin-Silica Inorganic Membrane for Direct Methanol Fuel Cell Application. International Journal of Renewable Energy Development, 6(2), 165-170.https://doi.org/10.14710/ijred.6.2.165-170

Microstructure-modified proton exchange membranes for high-performance direct methanol fuel cells

To lower methanol crossover and volume swelling degree, and to improve proton conductivity, a simple hot-mould-modifying method has been introduced to modify Nafion membrane for the direct methanol fuel cell application. To evaluate effect of the modification on properties of the Nafion membrane and fuel cell performance, a series of measurements of membranes and fuel cells have been carried out. The results show that, compared with the normal membrane, the modified Nafion membrane with regular spindle-type groove array possesses higher proton conductivity and methanol diffusion resistance, and 31.9% better dimensional stability, owing to its larger electrical double-layer capacitance come from the higher contact area between electron-electrode and ion electrolyte, and its more compact internal structure. And also, the direct methanol fuel cell based on the modified Nafion membrane shows 13.3% higher discharge power density and better long-time running performance than the normal one. Furthermore, this hot-mould-modifying method could be introduced into doping/coating-modified membranes reported in the current literature to further modify Nafion membranes, because this method is compatible with the current modifications.