Preparation Of Proton Exchange Membranes Research Articles

Preparation of proton exchange membrane with intrinsic micropores constructing efficient ion transport channels based on segmented copolymer (sulfonated polyimide)

The development of high conductivity proton exchange membranes (PEM) with efficient ion channels is a focus of fuel cell research. In this work, PEMs based on sulfonated polyimide are prepared by a simple synthesis route. The conformational change of the polymer depends on the type of polymeric chemical structure, leading to the formation of nanoscale cavities and ion channels for rapid proton transport, as evidenced by micropore porosities tests and proton conductivity tests. CO2 adsorption and desorption curves determined that the pore distribution of the polymer is 0.3–1.5 nm, and the specific surface area is up to 106.644 m3g−1, and the microphase separation channels are measured by X-ray diffraction. The introduction of microporous structures and microphase separation channels work together to make excellent electrochemical performance. The proton conductivity of SPI-B40 with the ion-exchange capacity (IEC) of 1.76 mmol g−1 is up to 0.146 S cm−1 at 80 °C, and the power density can reach 869 mW cm−2.

Precise Control of the Preparation of Proton Exchange Membranes via Direct Electrostatic Deposition.

In this work, we reported a novel preparation method for a proton exchange membrane (PEM) named, the direct electrostatic deposition method. In theory, any required thickness and size of PEM can be precisely controlled via this method. By direct electrostatic spraying of Nafion solution containing amino modified SiO2 nanoparticles onto a metal collector, a hybrid membrane of 30 μm thickness was fabricated. The DMFC assembled with a prepared ultrathin membrane showed a maximum power density of 124.01 mW/cm2 at 40 °C and 100% RH, which was 95.29% higher than that of Nafion. This membrane formation method provides potential benefits for the preparation of ultrathin PEMs.

Study on the CCM breakdown voltage of proton exchange membrane fuel cells

Proton exchange membrane (PEM) short circuits are one of the failure forms of fuel cells. In this paper, the change in breakdown voltage (BV) after the preparation of PEMs into catalyst coated membranes (CCMs) is studied, and the impact of the catalyst layer (CL) and its composition on the BV of the CCM is analysed. The results show that the BV of the CCM is significantly lower than that of the uncoated PEM. The higher the platinum (Pt) loading of the coated CL is, the lower the BV. Further research finds that the BV of the single-side CL-coated CCM only decreases when the CL side is connected to the positive pole of the power supply, while it is comparable to that of the PEM when the CL side is connected to the negative pole. The experimental results demonstrate that the Pt and carbon particles in the CCM undergo electrochemical reactions during the breakdown process when the CL is connected to the positive pole, which eventually leads to thermal breakdown. Therefore, when the BV is chosen for detecting whether the CCM preparation process causes PEM damage, single-side CL-coated CCM should be adopted, and the CL should be connected to the negative pole of the power supply.

Proton exchange membrane from the blend of poly(vinylidene fluoride) and functional copolymer: Preparation, proton conductivity, methanol permeability, and stability

A polymer electrolyte membrane is considered as the heart of fuel cells. Here we report the preparation of proton exchange membranes (PEMs) of poly (vinylidene fluoride) (PVDF) blend poly (methyl methacrylate)-co-poly (sodium-4-styrene sulfonate) (PMMA-co-PSSNa) by solvent evaporation method. Three different types of PEMs have been prepared by using different ratios of PVDF and PMMA-co-PSSNa copolymer. We have investigated the effect of concentration of PVDF on water uptake, ion exchange capacity, mechanical, thermal, and oxidative stability, proton conductivity (Km), and methanol permeability (PM) of the blend membranes. These blend PEMs showed good physicochemical and electrochemical properties along with thermal and oxidative stability. The membrane prepared from PVDF (45% w/w) to PMMA-co-PSSNa (55% w/w) exhibited optimum PM at room temperature (8.38 × 10−7 cm2s−1). This low fuel crossover and high relative selectivity can make our prepared blend membranes a potential candidate in polymer electrolyte membrane fuel cells (PEMFCs) or direct methanol fuel cells (DMFCs).

Cover Feature: Chemical Vapor Deposition for Advanced Polymer Electrolyte Fuel Cell Membranes (ChemElectroChem 8/2022)

The Cover Feature shows a generalised illustration of the dynamics of chemical vapour deposition for the preparation of proton exchange membranes. More information can be found in the Review by N. Bellomo et al.

Preparation and performance of sulfonated poly(ether ether ketone) membranes enhanced with ammonium ionic liquid and graphene oxide

The exploration of proton exchange membranes with excellent performance has always been under focus for improving the performance of proton exchange membrane fuel cells. In this study, novel ternary composite proton exchange membranes based on sulfonated poly(ether ether ketone) (SPEEK), triethylamine phosphate (TEAP) as the ammonium ionic liquid (AIL), and graphene oxide (GO) were prepared. The prepared membranes were characterized for their physical, physico-chemical, structural, morphological, thermal, mechanical, and electrical characteristics. The thermal stability of the SPEEK membrane was improved by the addition of GO and TEAP. GO was inserted into the composite membrane to form proton transfer channels. The amine ions in AIL formed acid–base pairs with the sulfonic acid group, whereas the oxygen-containing group on GO formed hydrogen bonds with the phosphate group. These groups interacted with each other to form a honeycomb-like structure, which anchored the AIL in the membrane and reduced its loss, providing additional sites for proton transport at higher temperatures. The proton conductivity of the SPEEK/AIL/GO-2 membrane reached 17.345 mS/cm at 120°C, which was 2.09 times higher than that of the pristine SPEEK membrane. This study provides the possibility for better preparation of proton exchange membranes used for high-temperature proton exchange membrane fuel cells.

Highly sulfonated poly(ether ether ketone) grafted on graphene oxide as nanohybrid proton exchange membrane applied in fuel cells

Highly sulfonated poly(ether ether ketone) (PEEK) polymer is hydrogenated and then readily grafted on GO to provide nanohybrid material GO-g-SPEEK. The material shows good enough properties for the preparation of proton exchange membranes. First, the GO-g-SPEEK membrane has much more water uptake but less water swelling compared with Nafion®, and an excellent proton conductivity of 0.219 Scm−1 at 90 °C. Then, it demonstrates a peak power density of 112 mWcm−2 when utilized in a H2/air fuel cell at circumstance temperature. Further, blending of the materials with Nafion leads to composite membranes of GO-g-SPEEK/Nafion, which has a close proton conductivity to that of GO-g-SPEEK but far higher cell performances. Of the composite membranes, GO-g-SPEEK/Nafion-33 reveals cell performance of 182 mWcm−2 at 25 °C and 213 mWcm−2 at 60 °C. These results indicate that Nafion might serve only as an enhancer of compatibility between membrane and Nafion-supported catalyst phase in the membrane electrode assembly, and therefore suggest that the GO-g-SPEEK may be a promising membrane material for the application in proton exchange membrane fuel cells.

A facile route for the preparation of proton exchange membranes using sulfonated side chain graphite oxides and crosslinked sodium alginate for fuel cell

Functionalized graphite oxide was prepared and subjected to sulfonation via a simple procedure in the presence of 1,4-butane sultone (BS) and sodium dodecylbenzenesulfonate (SDBS). The resulting sulfonated graphite oxides were incorporated into polystyrene sulfonicacid-co-maleic acid (PSSA-MA) crosslinked sodium alginate in different mass% to enhance the water uptake, mechanical stability and proton conductivity of the membranes. The physico-chemical changes in the resulting proton exchange membranes were investigated using Fourier transform infrared spectrometer (FT-IR), wide-angle X-ray diffractometer (WAXD), scanning electron microscope (SEM), differential scanning calorimeter (DSC) and thermogravimetric analyzer (TGA). The proton conductivity of the synthesized composite membranes was measured using a high precession impedance analyzer. Among the developed proton exchange membranes (PEMs), membranes containing 16 mass% of graphite oxide sulfonated with BS and SDBS respectively exhibited the highest proton conductivity of 0.133 and 0.145 S/cm at 80 °C. The ion exchange capacity (IEC) of these membranes was found to be 1.40 and 1.52 meq/g, respectively. The performance of the membranes was evaluated using fuel cell workstation at 80 °C. Among the membranes developed, 16 mass% of BS-GO and SDBS-GO incorporated membranes demonstrated the power density of 0.39 and 0.42 W/cm2, respectively. These properties are superior to the commercially available Nafion® 117 membrane. Thus, these proton exchange membranes developed here could be employed for fuel cell applications.

The use of Strong Magnetic Field Treatment for Preparation of Proton Exchange Membrane Doped by SeO2 and its electrochemical properties

The use of Strong Magnetic Field Treatment for Preparation of Proton Exchange Membrane Doped by SeO2 and its electrochemical properties

The roles of solvent type and amount of residual solvent on determining the structure and performance of sulfonated poly(ether ether ketone) proton exchange membranes

Our previous work demonstrated that the amount of residual solvent (RS) content plays an important role in determining the structure and properties of sulfonated poly(ether ether ketone) (SPEEK) membranes cast from dimethylacetamide (DMAc). In this work, another three most commonly used solvents during the preparation of proton exchange membranes (PEMs), including dimethylformamide (DMF), dimethylsulfoxide (DMSO) and N-methyl-2-pyrrolidone (NMP), were employed to prepare SPEEK membranes of different degrees of sulfonation (DSs) with controlled amount of RS content. It was found that the effect of RS content on membrane water uptake is quite universal, as the treated SPEEK membranes of the same DS always showed the same water uptake with the same amount of RS content, regardless of solvent types. Larger RS content always corresponded to the higher water uptake. For SPEEK membranes with relatively high DS, proton conductivity remained almost the same for the treated membranes cast by different solvents when the RS content is the same. While at low DS, the solvent type came into play and also affected the membrane structure and properties: the SPEEK membrane cast by DMSO always exhibited higher proton conductivity than those cast by other solvents with the same RS content. Such phenomena were related to the characteristic structure difference including the size of hydrophilic domains, crystalline structure and polymer chain mobility, which was caused by the different degree of solvent-polymer interaction.

Molecular dynamics simulation study of a polynorbornene-based polymer: A prediction of proton exchange membrane design and performance

A novel polymer material based on polynorbornenes prepared via ring-opening metathesis polymerization (ROMP) was intended to be used as proton exchange membranes. In order to study the microstructure and forecast their macro properties, molecular dynamics simulations were used to lucubrate the transport behavior of hydrated sulfonated polynorbornene-based (SPNB) proton exchange membrane at different temperatures. Simulation results have shown that SPNB membranes swell upon hydration and become phase segregated into hydrophobic and hydrophilic domains with sulfonic acid groups located at their interface. By evaluating the radial distribution function (RDF), it was observed that with increasing number of water molecules caused by the rising temperatures, which leading to more water molecules solvate the sulfur atoms and hydronium ions, the average sulfur-hydronium ion separation distance increased and larger water clusters formed. The results of the mean square displacements (MSDs) showed that the proton conductivity of the membrane with the designed structure was 0.056 S/cm which can meet the application requirements of the proton exchange membranes. Moreover, the simulated proton conductivities qualitatively followed the experimental data at 298 K, 323 K and 348 K, respectively. The molecular dynamics simulation can provide predictive performance of this designed polymer structure before its preparation, which is of guidance significance to the preparation of proton exchange membranes.

Nafion-Initiated ATRP of 1-Vinylimidazole for Preparation of Proton Exchange Membranes.

Nafion is one of the most widely investigated materials applied in proton exchange membranes. Interestingly, it was found that Nafion could serve as a macroinitiator to induce atom transfer radical polymerization (ATRP) on its C-F sites. In this study, poly(1-vinylimidazole) was selectively bonded on the side chains of Nafion via the Nafion-initiated ATRP process, which was confirmed by the measurements of (1)H/(19)F nuclear magnetic resonance spectra, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, differential scanning calorimeter and matrix-assisted laser desorption ionization-time-of-flight/time-of-flight mass spectrometry. The as-prepared Nafion-co-poly(1-vinylimidazole) (Nafion-PVIm) membranes, with tunable loading amount of imidazole rings, presented greatly enhanced proton conductivity and methanol resistivity due to their well-controlled chemical structures. Especially, chemically bonding PVIm with Nafion chains endowed the Nafion-PVIm membranes with high stability in proton conductivity. For the first time, we revealed the great potentials of the Nafion-initiated ATRP process in developing high-performance proton exchange membranes.

Nafion-functionalized electrospun poly(vinylidene fluoride) (PVDF) nanofibers for high performance proton exchange membranes in fuel cells

Nafion-functionalized electrospun poly(vinylidene fluoride) nanofibers show high performance in preparation of proton exchange membranes for fuel cells.

Preparation of proton exchange membranes by radiation-induced grafting of alpha methyl styrene–butyl acrylate mixture onto polyetheretherketone (PEEK) films

Radiation-induced graft copolymerization of alpha methyl styrene (AMS)–butyl acrylate (BA) mixture onto poly(etheretherketone) (PEEK) was carried out to produce copolymer films which were subsequently sulfonated to develop proton exchange membranes. The characterization of membranes was carried out with infrared spectroscopy (FTIR), differential scanning calorimetry, thermogravimetric analysis, X-ray diffraction analysis (XRD), contact angle and electron probe microanalysis (EPMA). The presence of sulfonic acid groups within the polymer matrix was confirmed by FTIR. The crystallinity of membranes decreased significantly upon sulfonation process. The melting temperature of the membranes also decreased as compared to the virgin and the grafted films. At the same time, glass transition temperature (Tg) of membranes increased as the grafting increased. Virgin film showed stable thermogram up to ~500 °C while the grafted film had two-step degradation pattern. Sulfonation introduced one additional decomposition range in the membrane. Contact angle images showed the hydrophilic nature of the membrane surface. The EPMA showed the presence of the sulphur across the membrane matrix in a homogenous manner. The membranes showed low resistivity of 62 Ω cm for the graft level of 27 %.

Fabrication of a micro-direct methanol fuel cell using microfluidics

AbstractA direct-methanol fuel cell containing three parts: microchannels, electrodes, and a proton exchange membrane (PEM), was investigated. Nafion resin (NR) and polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (PS) were used as PEMs. Preparation of PEMs, including compositing with other polymers and their solubility, was performed and their proton conductivity was measured by a four point probe. The results showed that the 5 % Nafion resin has lower conductivity than the 5 % PS solution. The micro-fuel cell contained two acrylic channels, PEM, and two platinum catalyst electrodes on a silicon wafer. The assembled micro-fuel cells used 2 M methanol at the flow rate of 1.5 mL min−1 in the anode channel and 5 × 10−3 M KMnO4 at the flow rate of 1.5 mL min−1 in the cathode channel. The micro-fuel cell with the electrode distance of 300 μm provided the power density of 59.16 μW cm−2 and the current density of 125.60 μA cm−2 at 0.47 V.

Nafion®-stabilised Pt/C electrocatalysts with efficient catalyst layer ionomer distribution for proton exchange membrane fuel cells

We report a facile method for the preparation of proton exchange membrane fuel cell (PEMFC) electrocatalysts from Nafion®-stabilised colloidal Pt nanoparticles (Nafion®-Pt/C), offering synthetically-directed formation of the Pt-ionomer interface and providing unprecedented control over the morphology of Pt particles on the carbon support. Electrochemical characterisation of the catalysts in aqueous acidic electrolytes using Rotating Disc Electrode (RDE) techniques revealed that Nafion®-Pt/C catalysts possessed similar specific activity and mass activity towards the oxygen reduction reaction (ORR) as commercial Pt/C catalysts, whilst requiring lower overall ionomer loadings. Combined with the near-100% utilisation measured for the Nafion®-Pt/C catalysts, this implies that Pt nanoparticles synthesised with Nafion® as a stabiliser can be ‘tuned’ to have simultaneous access to the reactant gas, the electron conducting carbon support and the proton conducting polymer electrolyte in the catalyst layer, thereby optimising the triple-phase reaction zone. By taking advantage of this bottom-up approach, which allows nanoscale control of the Nafion®–Pt–carbon interface, new opportunities exist to lower the Pt loading and the cost of the fuel cell.

Preparation of proton exchange membranes with high performance by a pulsed plasma enhanced chemical vapor deposition technique (PPECVD)

A pulsed plasma enhanced chemical vapor deposition technique has been employed to prepare sulfonated plasma polymerized membranes. The technique adopting such a pulse plasma discharge can avoid the further dissociation of active species and polymers formed by the plasma discharge during their polymerization and deposition and produces membranes with a higher content of proton exchange groups. The obtained membranes have higher water uptake capability and IECs, low methanol permeability and activation energy for proton conduction, and therefore show great promise for application in direct alcohol fuel cells.

Proton Exchange Membrane Based on Sulfonated Polyimide for Fuel Cells: State-of-the-Art and Recent Developments

Proton exchange membrane is one of the most important components for proton exchange membrane fuel cells (PEMFCs). The preparation of proton exchange membranes based on sulfonated polyimide (SPI) for PEMFCs in recent years was reviewed, and methods of improving the water stability and proton conductivity of such membranes were highlighted. It was suggested that preparation of novel SPI membranes or organic-inorganic composite SPI membranes should be a reasonable approach to strengthen their combination property.

Preparation of Proton Exchange Membranes by a Plasma Polymerization Method and Application in Direct Methanol Fuel Cells (DMFCs)

Preparation of Proton Exchange Membranes by a Plasma Polymerization Method and Application in Direct Methanol Fuel Cells (DMFCs)

High Performance Cross-Linked Poly(2-acrylamido-2-methylpropanesulfonic acid)-Based Proton Exchange Membranes for Fuel Cells

Poly(2-acrylamido-2-methylpropanesulfonic acid) (PAMPS) has been used for the preparation of proton exchange membranes (PEMs) due to the superior ability of sulfonic acid groups originated from AMP...