Nanotek Instruments, Inc.

Jiusheng Guo

Bor Z Jang

Aruna Zhamu

Jinjun Shi

Lulu Song

The present invention provides a carbon-cladded composite composition for use as a fuel cell flow field plate or bipolar plate. In one preferred embodiment, the composition comprises a core composite layer sandwiched between two clad layers, wherein (a) the clad layer comprises a conductive carbon or graphite material (e.g., carbon nano-tubes, nano-scaled graphene plates, graphitic nano-fibers, and fine graphite particles); (b) the core composite layer comprises a matrix resin and a conductive filler present in a sufficient quantity to render the composite layer electrically conductive with an electrical conductivity no less than 1 S/cm (preferably no less than 100 S/cm); and (c) the composition has a planar outer surface on each clad side having formed therein a fluid flow channel.

Carbon cladded composite flow field plate, bipolar plate and fuel cell

Disclosed is a nano-scaled graphene article comprising a non-woven aggregate of nano-scaled graphene platelets wherein each of the platelets comprises a graphene sheet or multiple graphene sheets and the platelets have a thickness no greater than 100 nm (preferably smaller than 10 nm) and platelets contact other platelets to define a plurality of conductive pathways along the article. The article has an exceptional thermal conductivity (typically greater than 500 WmK) and excellent electrical conductivity (typically greater than 1,000 S/cm). Thin-film articles of the present invention can be used for thermal management in micro-electronic devices and for current-dissipating on an aircraft skin against lightning strikes.

Nano-scaled graphene plate films and articles

A fuel cell including primarily (a) a membrane electrode assembly, which comprises (i) a proton exchange membrane having a front face and a rear face, (ii) an anode being coupled to the front face, and (iii) a cathode being coupled to the rear face; (b) a fuel permeation-controlling member positioned in front of the anode; the member being substantially impermeable to an organic fuel or water at an ambient temperature or below, but being permeable at a temperature higher than an activation temperature; (c) heating means in control relation to the fuel permeation-controlling member to activate fuel permeation through the member on demand. The invented fuel cell is compact and lightweight, with significantly reduced fuel crossover and improved fuel utilization efficiency. The fuel cell is particularly useful for powering small vehicles and portable devices such as a notebook computer, a personal digital assistant, a mobile phone, and a digital camera.

Organic vapor fuel cell

A lithium secondary battery comprising a positive electrode, a negative electrode comprising a carbonaceous material which is capable of absorbing and desorbing lithium ions, and a non-aqueous electrolyte disposed between the negative electrode and the positive electrode. The carbonaceous material comprises a graphite crystal structure having an interplanar spacing dof at least 0.400 nm (preferably at least 0.55 nm) as determined from a (002) reflection peak in powder X-ray diffraction. This larger interplanar spacing implies a larger interstitial space between two graphene planes to accommodate a greater amount of lithium. The battery exhibits an exceptional specific capacity, excellent reversible capacity, and long cycle life.

Carbon anode compositions for lithium ion batteries

A method of producing nano-scaled graphene platelets (NGPs) having an average thickness no greater than 50 nm, typically less than 2 nm, and, in many cases, no greater than 1 nm. The method comprises (a) intercalating a supply of meso-carbon microbeads (MCMBs) to produce intercalated MCMBs; and (b) exfoliating the intercalated MCMBs at a temperature and a pressure for a sufficient period of time to produce the desired NGPs. Optionally, the exfoliated product may be subjected to a mechanical shearing treatment, such as air milling, air jet milling, ball milling, pressurized fluid milling, rotating-blade grinding, or ultrasonicating. The NGPs are excellent reinforcement fillers for a range of matrix materials to produce nanocomposites. Nano-scaled graphene platelets are much lower-cost alternatives to carbon nano-tubes or carbon nano-fibers.

Production of ultra-thin nano-scaled graphene platelets from meso-carbon micro-beads

An electrically conductive laminate composition for fuel cell flow field plate or bipolar plate applications. The laminate composition comprises at least a thin metal sheet having two opposed exterior surfaces and a first exfoliated graphite composite sheet bonded to the first of the two exterior surfaces of the metal sheet wherein the exfoliated graphite composite sheet comprises: (a) expanded or exfoliated graphite and (b) a binder or matrix material to bond the expanded graphite for forming a cohered sheet, wherein the binder or matrix material is between 3% and 60% by weight based on the total weight of the first exfoliated graphite composite sheet. Preferably, the first exfoliated graphite composite sheet further comprises particles of non-expandable graphite or carbon in the amount of between 3% and 60% by weight based on the total weight of the non-expandable particles and the expanded graphite. Further preferably, the laminate comprises a second exfoliated graphite composite sheet bonded to the second surface of the metal sheet to form a three-layer laminate. Surface flow channels and other desired geometric features can be built onto the exterior surfaces of the laminate to form a flow field plate or bipolar plate. The resulting laminate has an exceptionally high thickness-direction conductivity and excellent resistance to gas permeation.

Laminated exfoliated graphite composite-metal compositions for fuel cell flow field plate or bipolar plate applications

A method of producing an electrically conductive composite composition, which is particularly useful for fuel cell bipolar plate applications. The method comprises: (a) providing a supply of expandable graphite powder; (b) providing a supply of a non-expandable powder component comprising a binder or matrix material; (c) blending the expandable graphite with the non-expandable powder component to form a powder mixture wherein the non-expandable powder component is in the amount of between 3% and 60% by weight based on the total weight of the powder mixture; (d) exposing the powder mixture to a temperature sufficient for exfoliating the expandable graphite to obtain a compressible mixture comprising expanded graphite worms and the non-expandable component; (e) compressing the compressible mixture at a pressure within the range of from about 5 psi to about 50,000 psi in predetermined directions into predetermined forms of cohered graphite composite compact; and (f) treating the so-formed cohered graphite composite to activate the binder or matrix material thereby promoting adhesion within the compact to produce the desired composite composition. Preferably, the non-expandable powder component further comprises an isotropy-promoting agent such as non-expandable graphite particles. Further preferably, step (e) comprises compressing the mixture in at least two directions. The method leads to composite plates with exceptionally high thickness-direction electrical conductivity.

Method of producing exfoliated graphite composite compositions for fuel cell flow field plates

This invention provides an electrically conductive, less anisotropic, recompressed exfoliated graphite article comprising a mixture of (a) expanded or exfoliated graphite flakes; and (b) particles of non-expandable graphite or carbon, wherein the non-expandable graphite or carbon particles are in the amount of between about 3% and about 70% by weight based on the total weight of the particles and the expanded graphite flakes combined; wherein the mixture is compressed to form the article having an apparent bulk density of from about 0.1 g/cmto about 2.0 g/cm. The article exhibits a thickness-direction conductivity typically greater than 50 S/cm, more typically greater than 100 S/cm, and most typically greater than 200 S/cm. The article, when used in a thin foil or sheet form, can be a useful component in a sheet molding compound plate used as a fuel cell separator or flow field plate. The article may also be used as a current collector for a battery, supercapacitor, or any other electrochemical cell.

Recompressed exfoliated graphite articles

Disclosed are processes for producing a fuel cell electrode and a membrane electrode assembly. In one preferred embodiment, the process comprises (a) preparing a suspension of catalyst particles dispersed in a liquid medium containing a polymer dissolved or dispersed therein; (b) dispensing the suspension onto a primary surface of a substrate selected from an electronically conductive catalyst-backing layer (gas diffuser plate) or a solid electrolyte membrane; and (c) removing the liquid medium to form the electrode that is connected to or integral with the substrate, wherein the polymer is both ion-conductive and electron-conductive with an electronic conductivity no less than 10S/cm and ionic conductivity no less than 10S/cm and the polymer forms a coating in physical contact with the catalyst particles or coated on the catalyst particles.

Process for producing fuel cell electrode

A precursor electro-catalyst composition for producing a fuel cell electrode. The precursor composition comprises (a) a molecular metal precursor dissolved or dispersed in a liquid medium and (b) a polymer dissolved or dispersed in the liquid medium, wherein the polymer is both ion-conductive and electron-conductive with an electronic conductivity no less than 10S/cm (preferably greater than 10S/cm) and ionic conductivity no less than 10S/cm (preferably greater than 10S/cm). Also disclosed is an electro-catalyst composition derived from this precursor composition, wherein the molecular metal precursor is converted by heat and/or energy beam to form nanometer-scaled catalyst particles and the polymer forms a matrix that is in physical contact with the catalyst particles, coated on the catalyst particles, and/or surrounding the catalyst particles as a dispersing matrix with the catalyst particles dispersed therein when the liquid is removed. The fuel cell comprising such a composition in an electrode exhibits a superior power output.

Electro-catalyst compositions for fuel cells

A controlled-release fuel cell comprising (a) a proton exchange membrane having a first surface and a second surface, a fuel electrode or anode being coupled to the first surface, and an oxidant electrode or cathode being coupled to the second surface; (b) a fuel flow field plate having surface channels positioned in front of the anode with the channels containing therein a controlled-release material that retains a liquid fuel at or below an ambient temperature, but releases the fuel at a temperature higher than an activation temperature to deliver a fuel vapor to the anode; (c) heating means in heat-supplying relation to the controlled-release material to activate fuel vapor release on demand at a desired rate; and (d) fuel supply means that feeds the liquid fuel to the controlled-release material. The invented fuel cell is compact and lightweight, with significantly reduced fuel crossover and improved fuel utilization efficiency. The fuel cell is particularly useful for powering small vehicles and portable devices such as a notebook computer, a personal digital assistant, a mobile phone, and a digital camera.

Controlled-release vapor fuel cell

A method of exfoliating a layered material to produce separated nano-scaled platelets having a thickness smaller than 100 nm. The method comprises: (a) providing a graphite intercalation compound comprising a layered graphite containing expandable species residing in an interlayer space of the layered graphite; (b) exposing the graphite intercalation compound to an exfoliation temperature lower than 650&#xb0; C. for a duration of time sufficient to at least partially exfoliate the layered graphite without incurring a significant level of oxidation; and (c) subjecting the at least partially exfoliated graphite to a mechanical shearing treatment to produce separated platelets. The method can further include a step of dispersing the platelets in a polymer or monomer solution or suspension as a precursor step to nanocomposite fabrication.

Low-temperature method of producing nano-scaled graphene platelets and their nanocomposites

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.

Self-humidifying proton exchange membrane, membrane-electrode assembly, and fuel cell

This invention provides a moldable, multiple-layer composite composition, which is a precursor to an electrically conductive composite flow field plate or bipolar plate. In one preferred embodiment, the composition comprises a plurality of conductive sheets and a plurality of mixture layers of a curable resin and conductive fillers, wherein (A) each conductive sheet is attached to at least one resin-filler mixture layer; (B) at least one of the conductive sheets comprises flexible graphite; and (C) at least one resin-filler mixture layer comprises a thermosetting resin and conductive fillers with the fillers being present in a sufficient quantity to render the resulting flow field plate or bipolar plate electrically conductive with a conductivity no less than 100 S/cm and thickness-direction areal conductivity no less than 200 S/cm.

Highly conductive, multi-layer composite precursor composition to fuel cell flow field plate or bipolar plate

The present invention provides a method of exfoliating a layered material (e.g., graphite and graphite oxide) to produce nano-scaled platelets having a thickness smaller than 100 nm, typically smaller than 10 nm. The method comprises (a) dispersing particles of graphite, graphite oxide, or a non-graphite laminar compound in a liquid medium containing therein a surfactant or dispersing agent to obtain a stable suspension or slurry; and (b) exposing the suspension or slurry to ultrasonic waves at an energy level for a sufficient length of time to produce separated nano-scaled platelets. The nano-scaled platelets are candidate reinforcement fillers for polymer nanocomposites. Nano-scaled graphene platelets are much lower-cost alternatives to carbon nano-tubes or carbon nano-fibers.

Growing community of inventors

Centerville, OH, United States of America

Jiusheng Guo