摘要:
A twin-wire arc deposition method for depositing a nano-structured catalyst coating onto a solid electrolyte membrane or an electrode substrate from a precursor catalyst material selected from the group consisting of a metal, metal alloy, metal compound, and ceramic material. The method includes the steps of (a) providing an ionized arc nozzle comprising two consumable electrode and a working gas flow to form an ionized arc between the two electrodes, wherein the consumable electrodes provide the precursor catalyst material vaporizable therefrom by the ionized arc; (b) operating the arc nozzle to heat and at least partially vaporize the precursor catalyst material for providing a stream of nanometer-sized vapor clusters of the precursor catalyst material into a chamber in which the membrane or the electrode substrate has been placed; and (c) introducing a stream of a carrier gas into the chamber to impinge upon the stream of precursor vapor clusters to produce depositable nano clusters which are carried by the carrier gas to deposit onto a first side of the membrane or the electrode substrate for forming the nano-structured catalyst coating. Such a catalyst-coated membrane or electrode can be incorporated as a part of a fuel cell.
摘要:
A hydrogen generator apparatus that delivers a hydrogen stream at a controlled rate to a fuel cell. The apparatus comprises a fuel tank, a wicking material in the fuel tank, a fluid retained in the wicking material, a first disc bounding the wicking material and comprising a hydrophilic membrane for receiving the fluid from the wicking material by a wicking pressure to form a fluid-wetted surface, a second disc having a porous surface area with the second disc being in contact with the first disc with the two discs moveable relative to each other, a catalyst on the porous surface to form a catalyst-coated surface, and hydrogen generated by hydrolyzation of the fluid contacting the catalyst due to a relative motion between the first disc and the second disc. Major features of this apparatus include simplicity, compactness and portability, hydrogen production rate adjustability, reliability, the ability to operate in any orientation and, in one preferred embodiment, a feedback mechanism to automatically maintain a constant pressure supply of hydrogen or constant hydrogen flow rate. The invention also provides an actively or passively controlled power source featuring such a hydrogen generator.
摘要:
A direct-write micro- or nano-lithography method for depositing a functional material with a preferred orientation onto a target surface. The method includes the steps of (1) forming a precursor fluid to the functional material; (2) operating a sub-micrometer tip to discharge, on contact, the precursor fluid onto the target surface so as to produce a desired pattern of deposited functional material in sub-micrometer dimensions; and (3) during the pattern-producing step, subjecting the deposited material to a highly localized electric or magnetic field for attaining a preferred orientation in at least a portion of the functional material. The method is particularly useful for microfabrication, nanotechnology, and molecular electronics.
摘要:
A core-shell composition for gas storage, comprising a hollow or porous core and a shell comprising a nanocomposite. The nanocomposite is composed of an exfoliated layered filler dispersed in a matrix material, which provides high mechanical strength to hold a high pressure gas such as hydrogen and high resistance to gas permeation. Alternatively, the porous core may contain a plurality of cavities selected from the group consisting of shell-hollow core micro-spheres, shell-porous core micro-spheres, and combinations thereof. These core-shell compositions, each capable of containing a great amount of hydrogen gas, can be used to store and feed hydrogen to fuel cells that supply electricity to apparatus such as portable electronic devices, automobiles, and unmanned aerial vehicles where mass is a major concern. A related method of storing and releasing hydrogen gas in or out of a plurality of core-shell compositions is also disclosed.
摘要:
A method for the preparation of a monolayer of meso-scaled particles within a size range of one nanometer to several hundreds of microns. The method includes the steps of (A) providing a thin liquid film onto an external surface of a rotary member; (B) dispensing meso-scaled particles at a desired rate onto an external surface of the thin liquid film so as to position the particles at a gas-liquid interface; (C) forming a uniform monolayer of the particles on the gas-liquid interface; and (D) transferring the monolayer from the gas-liquid interface to a solid substrate. Monolayers of meso-scaled particles on solid surfaces are useful in many areas of science and technology, including functional coatings that modify the physical and chemical properties of the underlying surfaces. The method is particularly useful for the preparation of catalyzed proton exchange membranes for fuel cell applications.
摘要:
This invention provides a highly electrically conductive sheet molding compound (SMC) composition and a fuel cell flow field plate or bipolar plate made from such a composition. The composition comprises a top sheet, a bottom sheet, and a resin mixture sandwiched between the top sheet and the bottom sheet. At least one of the top sheet and bottom sheet comprises a flexible graphite sheet, which has a substantially planar outer surface having formed therein a fluid flow channel. Further, the resin mixture comprises a thermoset resin and a conductive filler present in a sufficient quantity to render the flow field plate electrically conductive enough to be a current collector (preferably with a conductivity no less than 100 S/cm). Preferably, both the top and bottom surfaces are flexible graphite sheets, each having a substantially planar outer surface having therein a fluid flow channel formed by embossing. These two flexible graphite sheets are well-bonded by the middle resin mixture layer to form a highly conductive bipolar plate, which is particularly useful for proton exchange membrane fuel cell applications.
摘要:
A self-humidifying proton exchange membrane (PEM) composition, a membrane-electrode assembly, and a fuel cell. The PEM composition comprises (a) a proton-conducting polymer; (b) a catalyst that promotes the chemical reaction between hydrogen and oxygen molecules to generate water in the membrane, and (c) a deliquescent material dispersed in this polymer. The amount of catalyst is preferably 0.01%-50% by weight on the basis of the polymer weight. The catalyst is preferably a metal catalyst selected from the group consisting of platinum, gold, palladium, rhodium, iridium, ruthenium, and mixtures and alloys thereof. Suitable deliquescent materials include, but are not limited to, calcium chloride, calcium bromide, potassium biphosphate, potassium acetate and combinations thereof. A deliquescent material absorbs and retains an essentially constant amount of moisture to keep the proton mobile in the PEM structure. The fuel cell containing such a PEM composition can be used in a higher temperature and/or lower-humidity environment.
摘要:
Disclosed are a nano-composite composition and a method of making such a composite that is composed of a matrix material and dispersed reinforcement nano-scaled graphene plates (NGPs) that are substantially aligned along at least one specified direction or axis. The method comprises: (a) providing a mixture of nano-scaled graphene plates (NGPs) and a matrix material in a fluent state; (b) extruding the mixture to form a filament wherein NGPs are aligned along a filament axis; (c) aligning a plurality of segments of the filament in a first direction, or moving the filament back and forth along a first direction and its opposite direction, to form a NGP-matrix filament preform; and (d) consolidating the preform to form the nanocomposite material. Also disclosed is a method of making a nano-composite fiber.
摘要:
A process for producing a nano-scaled graphene plate. The material comprises a sheet of graphite plane or a multiplicity of sheets of graphite plane. The graphite plane is composed of a two-dimensional hexagonal lattice of carbon atoms and the plate has a length and a width parallel to the graphite plane and a thickness orthogonal to the graphite plane with at least one of the length, width, and thickness values being 100 nanometers or smaller. The process for producing nano-scaled graphene plate material comprises the steps of: a). partially or fully carbonizing a precursor polymer or heat-treating petroleum or coal tar pitch to produce a polymeric carbon containing micron- and/or nanometer-scaled graphite crystallites with each crystallite comprising one sheet or a multiplicity of sheets of graphite plane; b). exfoliating the graphite crystallites in the polymeric carbon; and c). subjecting the polymeric carbon containing exfoliated graphite crystallites to a mechanical attrition treatment to produce the nano-scaled graphene plate material.
摘要:
An open, liquid-state electrochemical cell that can be used as a primary or rechargeable power source for various miniaturized or portable electronic devices. The cell is composed of flexible and thin layers of anode, cathode and electrolyte materials with the electrolyte layer being exposed to open air. The electrolyte with an open configuration avoids the accumulation of gases upon storage of the cell. The electrolyte includes (a) a deliquescent material for keeping the open cell wet at all times and (b) an ion conductive material for transporting ions across the electrolyte layer. The electrolyte does not include a water-soluble polymer. The invention also provides a multi-cell battery that contains cells exhibiting the above-described features. The cell or battery, along with an electronic component, may be attached to a flexible substrate to make a functional device.