62 results about "Methanol crossover" patented technology

An electrolyte composition that shows low methanol cross-over and exhibits high proton conductivity when used as a solid electrolyte for solid polymer fuel cells or the like, and a solid electrolyte membrane and a solid polymer fuel cell that use the electrolyte composition are provided. This electrolyte composition comprises a perfluorocyclobutane-containing polymer having a specific structure. High proton conductivity is provided by sulfonic acid groups connected to the benzene rings. Reduction of methanol crossover is realized by introduction of a rigid structure with aromatic rings, or a combination o a rigid structure with aromatic rings and a three-dimensional cross-linked structure.

An ion exchange composition membrane is made up of dispersed natural clay and/or organized clay in ion conducting polymeric film as a methanol barrier material. The membrane exhibits low methanol crossover, high proton conductivity and is thus suitable for use in direct methanol fuel cells with low costal advantage.

Provided are a proton-exchange membrane of which the ionic conductivity is high and the methanol crossover is low, and a fuel cell of high power that comprises the proton-exchange membrane. The proton-exchange membrane has a structure of mesogen-containing organic molecular chains and a proton-donating group-containing group covalent-bonding to a silicon-oxygen three-dimensional crosslinked matrix, in which at least a part of the organic molecular chains are oriented to form an aggregate thereof; and the fuel cell comprises the membrane.

A new class of hybrid organic-inorganic materials, and methods of synthesis, that can be used as a proton exchange membrane in a direct methanol fuel cell. In contrast with Nafion® PEM materials, which have random sulfonation, the new class of materials have ordered sulfonation achieved through self-assembly of alternating polyimide segments of different molecular weights comprising, for example, highly sulfonated hydrophilic PDA-DASA polyimide segment alternating with an unsulfonated hydrophobic 6FDA-DAS polyimide segment. An inorganic phase, e.g., 0.5–5 wt % TEOS, can be incorporated in the sulfonated polyimide copolymer to further improve its properties. The new materials exhibit reduced swelling when exposed to water, increased thermal stability, and decreased O₂ and H₂ gas permeability, while retaining proton conductivities similar to Nafion®. These improved properties may allow direct methanol fuel cells to operate at higher temperatures and with higher efficiencies due to reduced methanol crossover.

The invention discloses a direct methanol fuel cell capable of realizing pure methanol supply. The fuel cell comprises a cell shell, and a pervaporation membrane which is fixed on the cell shell and divides an inner chamber into a methanol fuel chamber and a steam chamber, wherein an anode flow field plate, a membrane electrode and a cathode flow field plate are sequentially arranged above the steam chamber from bottom to top in a stacking manner; a hollow cover plate covering a cathode collector plate is arranged at an open end of the cell shell in an insulation manner; a hydrophilic porous plate with hydrophily is arranged between the anode flow field plate and the anode side of the membrane electrode; a hydrophobic porous plate with hydrophobicity is arranged between the cathode side of the membrane electrode and the cathode flow field plate. According to the invention, continuous vaporization methanol supply is guaranteed, methanol crossover is restrained while cathode water is promoted to be reversely supplemented to the anode to participate in reaction, on the premise of guaranteeing output performance of the cell, the energy density of the cell is increased effectively, high-concentration methanol supply even pure methanol supply of the cell is realized and the service life of the cell is prolonged greatly.

A polysiloxane compound and a fuel cell including the same where the polysiloxane compound is an organic polymer siloxane compound containing sulfonic acid groups. By using the organic polymer siloxane compound containing sulfonic acid groups, a polymer electrolyte membrane having superior characteristics such as dimensional stability and ionic conductivity, without affecting the amount of methanol crossover, can be obtained by reducing swelling due to liquids.

A fuel cell has at least one electrode having channels for delivering reactants, products, or both. The electrode is an anode or cathode of the fuel cell, or both. The electrode can serve as both a liquid diffusion layer and a flow field plate, thus replacing the traditional elements of carbon paper, cloth diffusion layer, and anode current collector. In some aspects, the fuel cell uses methanol, and the electrode is formed from flexible graphite. The electrode can have a structure sufficient to permit methanol diffusion while preventing methanol crossover. The electrode can also improve volumetric power density and eliminate contact resistance typically present between a conventional flow field plate and conventional diffusion electrode layer.

A method and device for reducing or substantially eliminating methanol crossover from the anode to the cathode of a direct methanol fuel cell and for increasing catalyst efficiency in which a catalyst ink layer comprising an electron conductive and proton conductive binder material is applied either to the anode electrode or the electrolyte layer of the direct methanol fuel cell.

A sulfonated copolymer including a crosslinking functional group and a fuel cell including a polymeric composition of the same are provided. The sulfonated copolymer including a crosslinking functional group can remarkably reduce methanol crossover and maintain superior dimensional stability and ionic conductivity by reducing swelling.

A polymer electrolyte membrane including a polysilsesquioxane group-containing copolymer and an ionic conductive polymer is provided. A method of preparing the polymer electrolyte membrane and a fuel cell including the polymer electrolyte membrane is also provided. The polymer electrolyte membrane has improved ion conductivity and an improved ability to suppress methanol crossover, and therefore can be used as an electrolyte membrane for a fuel cell, including a direct methanol fuel cell.

The present invention intends to provide a fuel cell being capable of preventing the methanol crossover in a simple and easy manner and being excellent in fuel utilization rate and the like. A fuel cell 30 of the present invention includes a polymer electrolyte membrane 11, an anode 23 and a cathode 25 sandwiching the polymer electrolyte membrane 11, an anode-side separator 17 having a fuel flow channel, a cathode-side separator 21 having an oxidant flow channel, and gaskets 26 and 27 interposed between the anode-side and cathode-side separators 17 and 21 and the periphery of the polymer electrolyte membrane 11. In the fuel cell 30, the orthographic projection area of the anode catalyst layer 31 included in the anode 23 seen from the direction normal to an MEA is set to be larger than the orthographic projection area of the anode porous substrate 15 included in the anode 23 seen from the direction normal to the MEA.

The present invention includes method, compositions and devices including acid-base polymer membranes with high proton conductivity at low relative humidity, good thermal and mechanical stabilities and low methanol crossover. The acid-base polymer membrane includes an acidic polymer mixed with a basic polymer. The acidic polymer includes an acidic group attached to an aromatic polymer, while the basic polymer includes at least one heterocyclic ring structure attached to an aromatic polymer.

An acid-base proton conducting polymer blend membrane is provided. The acid-base proton conducting polymer blend membrane comprises a first acidic polymer having acidic subunits, a second basic polymer having basic subunits, and a third polymer containing one or more functional units for improving membrane conductivity, flexibility, water remaining ability, dimension stability, and methanol crossover. In one embodiment, the acid-base polymer blend membrane of the present invention comprises a first acidic polymer having acidic subunits, a second basic polymer having basic subunits, wherein at least one of the first acidic and second basic polymer comprises one or more functional units to improve the properties of the membrane. The functional units include hydrophilic units, methanol blocking units, methanol blocking units, dimensional stabilizer units, and flexible units.

Provided is a polymer electrolyte membrane including an inorganic nanoparticle bonded with a proton-conducting group, a solid acid and a proton-conducting polymer. The inorganic nanoparticle bonded with the proton-conducting group may be obtained by reacting a compound including a proton-conducting group with a metal precursor. The polymer electrolyte membrane has significantly enhanced proton conductivity and reduced methanol crossover.

Conductivity of carboxylic acid membranes can be increased for use in fuel cells when the membrane comprises a Lewis base, which has, in its protonated form, a pKa greater than the pKa of the carboxylic acid groups of the membrane. When the invention is employed in direct methanol fuel cells, water transport and methanol crossover though the membrane are decreased compared to conventional direct methanol fuel cells employing sulfonic acid membranes.

A polymer electrolyte membrane including an ionic conducting polymer and a light-irradiated product of a photoacid generator (PAG), a method of manufacturing the same, and a fuel cell using the same. The polymer electrolyte membrane has excellent proton conductivity and homogeneity by radiating light such as UV light onto the PAG, thereby producing an acid radical which generates an acid. The polymer electrolyte membrane also suppresses methanol crossover well. The polymer electrolyte membrane can be used as an electrolyte membrane of a fuel cell, for example, a direct methanol fuel cell.

The present invention provides a novel polyimide containing a diamine component having a fluorene skeleton and a novel polyimide-based polymer electrolyte membrane containing this polyimide as a main component and having properties based on this polyimide (for example, high resistance to methanol crossover). The polyimide of the present invention contains a structural unit (P) represented by the following formula (1). The polyimide-based polymer electrolyte membrane of the present invention contains the polyimide of the present invention as a main component.

An electrolyte membrane includes a nanocomposite ion complex that is a reaction product of a nanocomposite with a basic polymer. The nanocomposite includes a polymer having a sulfonic acid group and an unmodified clay. Either the unmodified clay has a layered structure and is dispersed in the polymer having the sulfonic acid group, and the polymer is intercalated between layers of the clay or the unmodified clay has an exfoliated structure and the exfoliated layers of the unmodified clay are dispersed in the polymer. The electrolyte membrane shows high mechanical strength, high ionic conductivity, and excellent methanol crossover impeding properties even when the degree of sulfonation of the polymer having the sulfonic acid group is high. When a methanol aqueous solution is used as a fuel, the fuel cell including the electrolyte membrane has a low methanol crossover, and thus, has a high operational efficiency and a long lifetime.

An electrochemical device having an electrolyte having an anode side and a cathode side, at least one consumable carbonaceous material disposed on the anode side, and a chemical barrier disposed on the anode side of the electrolyte, which chemical barrier reduces crossover of the at least one consumable carbonaceous material through the electrolyte to the cathode side. In accordance with one preferred embodiment, the electrochemical device is a direct methanol fuel cell, the consumable carbonaceous material is methanol disposed in an aqueous solution, and the chemical barrier is produced by the presence of an additive disposed in the methanol solution which attaches to potential methanol crossover sites in the electrolyte, thereby precluding methanol crossover using such sites. One such suitable additive is iso-propanol.

A solid acid having a core of calixarene or calix resorcinarene. The solid acid is an ion conducting compound in which at least one of the hydroxyl groups is substituted by an organic group having a cation exchange group at a terminal end, a polymer electrolyte membrane including the same, and a fuel cell using the polymer electrolyte membrane. The polymer electrolyte membrane can provide low methanol crossover and high ionic conductivity. Accordingly, a fuel cell having high efficiency can be obtained by using the polymer electrolyte membrane.

A polymer electrolyte membrane, a method of manufacturing the same, and a fuel cell including the polymer electrolyte membrane are provided, wherein the polymer electrolyte forms an interpenetrating polymer network (IPN) of a polymer by simple blending of a hydrophobic polyimide having a reactive terminal group and a hydrophilic aromatic polymer having ion conductivity. The polymer electrolyte membrane has reduced swelling properties due to highly dense crosslinking of polyimide through the reactive terminal group, shows high ion conductivity at low humidity, and has methanol crossover suppressing ability. Accordingly, a fuel cell with improved electric and mechanical properties can be provided.

When using a measurement of a crossover current density by the Gotesfeld method or a measurement of a methanol permeation coefficient by gas chromatography or by liquid chromatography, a measure for crossover amount may be given but the interrelation with a crossover loss is not clearly known and thus, it could not be possible to evaluate a degree of the crossover loss. The present invention has for its object the provision of a novel measuring method that is able to measure a methanol crossover loss directly.

The measuring method is characterized by measuring a crossover loss of MEA for methanol fuel cell from a difference between a voltage when a cathode catalyst layer is not influenced by methanol crossover and a voltage when the cathode catalyst layer is influenced by the methanol crossover.

A nanocomposite includes metal-carbon nanotubes and a sulfonated polysulfone. In the nanocomposite, the sulfonated polysulfone and the metal-carbon nanotubes have strong attraction therebetween due to π-π interactions or van der Waals interactions, and thus the nanocomposite has excellent ionic conductivity and mechanical properties. In addition, the nanocomposite includes a metal that can be used as a catalyst for an anode, and thus the reduction in power generation caused by methanol crossover can be minimized. Therefore, a nanocomposite electrolyte membrane prepared using the nanocomposite can minimize the reduction in power generation caused by the crossover of a polar organic fuel such as methanol. In a fuel cell employing the nanocomposite electrolyte membrane, when an aqueous methanol solution is used as a fuel, crossover of the methanol is more suppressed, and accordingly, the fuel cell has an improved operating efficiency and a longer lifetime.

The invention discloses a proton exchange membrane made from a high polymer-metal complex-heteropoly acid material and a preparation method thereof. The preparation method comprises the following steps of: introducing a side chain onto a high polymer; introducing an organic ligand onto the side chain; preparing an organic ligand; introducing a multi-tooth ligand onto the side chain; generating a high molecular metal complex; introducing heteropoly acid at the tail end of the side chain; preparing a film with a tape casting method; and the like. As proved by testing, the proton conductivity of the proton exchange membrane prepared by the method is up to the magnitude order level of 10-2S/cm at the temperature of 100-140 DEG C, the methanol crossover coefficient is lower than the magnitude order of 10<-8>-10<-7> cm<2>/s, and the use requirement of a fuel cell, in particular a methanol fuel battery proton exchange membrane can be met.