Nanotek Instruments, Inc.

Global Graphene Group, Inc.

Nantek Instuments, Inc.

Yanbo Wang

Bor Z Jang

Aruna Zhamu

Hui He

Guorong Chen

Qing Fang

Xiqing Wang

Wei Xiong

Lucy Fu

Xiging Wang

Yi-jun Lin

Zhenning Yu

Provided is a process for producing a thin film graphene-bonded metal foil current collector for a battery or supercapacitor, said process comprising: (a) providing a graphene suspension comprising graphene sheets dispersed in a liquid medium; (b) operating a micro-gravure coater to deposit a layer of the graphene suspension onto at least one of the two primary surfaces of a metal foil to form a wet layer of graphene deposited thereon; and (c) removing said fluid medium from the deposited wet layer to form a dry layer of graphene, having a layer thickness from 1 nm to 100 nm. Optionally, the process may include heat treating the dry layer of graphene at a temperature from 35° C. to 3,000° C.

Process for producing graphene-protected metal foil current collector for a battery or supercapacitor

Provided is a laminated graphitic layer as an elastic heat spreader, the layer comprising: (A) a plurality of graphitic or graphene films prepared from (i) graphitization of a polymer film or pitch film, (ii) aggregation or bonding of graphene sheets, or (iii) a combination of (i) and (ii), wherein the graphitic or graphene film has a thermal conductivity of at least 200 W/mK, an electrical conductivity no less than 3,000 S/cm, and a physical density from 1.5 to 2.25 g/cm; and (B) a conducting polymer network adhesive that bonds together the graphitic or graphene films to form the laminated graphitic layer; wherein the conductive polymer network adhesive is in an amount from 0.001% to 30% by weight and wherein the laminated graphitic layer preferably has a fully recoverable tensile elastic strain from 1% to 50% and an in-plane thermal conductivity from 100 W/mK to 1,750 W/mK.

Graphitic film-based elastic heat spreaders

A dual electroplating cell comprising: (a) an electrolyte component containing therein ions of a first metal; (b) a porous cathode current collector having surface areas to capture and store metal ions directly thereon, wherein the cathode current collector has a specific surface area greater than 100 m/g that is in direct contact with said electrolyte; (c) a porous anode current collector having surface areas to capture and store metal ions thereon, wherein the anode current collector has a specific surface area greater than 100 m/g that is in direct contact with the electrolyte; (d) a porous separator disposed between the anode and the cathode; and (e) an ion source of the first metal disposed in the anode current collector or the cathode current collector and in electronic contact therewith to obtain an open circuit voltage (OCV) from 0.3 volts to 3.5 volts when the cell is made.

Rechargeable dual electroplating cell

A rechargeable lithium-sulfur cell comprising a cathode, an anode, a separator electronically separating the two electrodes, a first electrolyte in contact with the cathode, and a second electrolyte in contact with the anode, wherein the first electrolyte contains a first concentration, C, of a first lithium salt dissolved in a first solvent when the first electrolyte is brought in contact with the cathode, and the second electrolyte contains a second concentration, C, of a second lithium salt dissolved in a second solvent when the second electrolyte is brought in contact with the anode, wherein Cis less than C. The cell exhibits an exceptionally high specific energy and a long cycle life.

Lithium-sulfur secondary battery containing gradient electrolyte

Disclosed is a facile and cost effective method of producing metal-doped nano silicon powder or graphene-doped metal-doped silicon nano powder having a particle size smaller than 100 nm. The method comprises: (a) preparing a silicon precursor/metal precursor/graphene nano composite; (b) mixing the silicon precursor/metal precursor/graphene nano composite with a desired quantity of magnesium; (c) converting the silicon precursor to form a mixture of graphene-doped silicon and a reaction by-product through a thermal and/or chemical reduction reaction; and (d) removing the reaction by-product from the mixture to obtain graphene-doped metal-doped silicon nano powder.

Methods for mass-producing silicon nano powder and graphene-doped silicon nano powder

A process for producing a highly oriented graphene film, comprising: (a) preparing a pristine graphene dispersion having oxygen-free pristine graphene sheets dispersed in a fluid medium; (b) dispensing and depositing the dispersion onto a supporting substrate to form a layer of oriented pristine graphene, including subjecting the pristine graphene dispersion to an orientation-inducing stress; (c) removing the fluid medium to form a dried layer of pristine graphene; (d) stacking at least two layers of dried pristine graphene to form a mass of multiple layers of dried pristine graphene; and (e) heat treating the mass of multiple layers of dried pristine graphene at a first heat treatment temperature higher than 2,000&#xb0; C. under a compressive stress for a sufficient period of time to produce the highly oriented graphene film.

Process for producing highly oriented graphene films

The present invention provides an anode electrode of a lithium-ion battery, comprising an anode active material-coated graphene sheet, wherein the graphene sheet has two opposed parallel surfaces and at least 50% area of one of the surfaces is coated with an anode active material and wherein the graphene material is in an amount of from 0.1% to 99.5% by weight and the anode active material is in an amount of at least 0.5% by weight (preferably at least 60%), all based on the total weight of the graphene material and the anode active material combined.

Anode containing active material-coated graphene sheets and lithium-ion batteries containing same

A rechargeable lithium-sulfur cell comprising an anode, a separator and/or electrolyte, and a sulfur cathode, wherein the cathode comprises (a) exfoliated graphite worms that are interconnected to form a porous, conductive graphite flake network comprising pores having a size smaller than 100 nm; and (b) nano-scaled powder or coating of sulfur, sulfur compound, or lithium polysulfide disposed in the pores or coated on graphite flake surfaces wherein the powder or coating has a dimension less than 100 nm. The exfoliated graphite worm amount is in the range of 1% to 90% by weight and the amount of powder or coating is in the range of 99% to 10% by weight based on the total weight of exfoliated graphite worms and sulfur (sulfur compound or lithium polysulfide) combined. The cell exhibits an exceptionally high specific energy and a long cycle life.

Rechargeable lithium-sulfur battery having a high capacity and long cycle life

A rechargeable lithium-selenium cell comprising a cathode having a cathode active material selected from Se or SeS(x/y ratio=0.01 to 100), an anode having an anode active material, a porous separator electronically separating the anode and the cathode, a non-flammable quasi-solid electrolyte in contact with the cathode and the anode, wherein the electrolyte contains a lithium salt dissolved in a first organic liquid solvent with a lithium salt concentration sufficiently high (at least 2.0 M, more preferably &#x3e;3.0 M) so that the electrolyte exhibits a vapor pressure less than 0.01 kPa when measured at 20&#xb0; C., a flash point at least 20 degrees Celsius higher than the flash point of the first organic liquid solvent alone, a flash point higher than 150&#xb0; C., or no flash point. This battery cell is non-flammable and safe, has a long cycle life, high capacity, and high energy density.

Lithium-selenium secondary batteries having non-flammable electrolyte

Disclosed is a facile and cost effective method of producing nano silicon powder or graphene-doped silicon nano powder having a particle size smaller than 100 nm. The method comprises: (a) preparing a silicon precursor/graphene nano composite; (b) mixing the silicon precursor/graphene nano composite with a desired quantity of magnesium; (c) converting the silicon precursor to form a mixture of graphene-doped silicon and a reaction by-product through a thermal and/or chemical reduction reaction; and (d) removing the reaction by-product from the mixture to obtain graphene-doped silicon nano powder.

A method of operating a lithium-ion cell comprising (a) a cathode comprising a carbon or graphitic material having a surface area to capture and store lithium thereon; (b) an anode comprising an anode active material; (c) a porous separator disposed between the two electrodes; (d) an electrolyte in ionic contact with the two electrodes; and (e) a lithium source disposed in at least one of the two electrodes to obtain an open circuit voltage (OCV) from 0.5 volts to 2.8 volts when the cell is made; wherein the method comprises: (A) electrochemically forming the cell from the OCV to either a first lower voltage limit (LVL) or a first upper voltage limit (UVL), wherein the first LVL is no lower than 0.1 volts and the first UVL is no higher than 4.6 volts; and (B) cycling the cell between a second LVL and a second UVL.

Method of operating a lithium-ion cell having a high-capacity cathode

A separator-electrolyte layer product for use in a lithium battery, comprising: (a) a porous thin-film separator selected from a porous polymer film, a porous mat, fabric, or paper made of polymer or glass fibers, or a combination thereof, wherein the separator has a thickness less than 500 &#x3bc;m; and (b) a non-flammable quasi-solid electrolyte containing a lithium salt dissolved in a liquid solvent up to a concentration no less than 3 M; wherein the porous thin-film separator is coated with the quasi-solid electrolyte so that the layer product exhibits a vapor pressure less than 0.01 kPa when measured at 20&#xb0; C., a vapor pressure less than 60% of the vapor pressure of the liquid solvent alone, a flash point at least 20 degrees Celsius higher than a flash point of the first liquid solvent alone, a flash point higher than 150&#xb0; C., or no detectable flash point.

Non-flammable quasi-solid electrolyte-separator layer product for lithium battery applications

A process for producing a separator-electrolyte layer for use in a lithium battery, comprising: (a) providing a porous separator; (b) providing a quasi-solid electrolyte containing a lithium salt dissolved in a first liquid solvent up to a first concentration no less than 3 M; and (c) coating or impregnating the separator with the electrolyte to obtain the separator-electrolyte layer with a final concentration&#x2267;the first concentration so that the electrolyte exhibits a vapor pressure less than 0.01 kPa when measured at 20&#xb0; C., a vapor pressure less than 60% of that of the first liquid solvent alone, a flash point at least 20 degrees Celsius higher than a flash point of the first liquid solvent alone, a flash point higher than 150&#xb0; C., or no detectable flash point. A battery using such a separator-electrolyte is non-flammable and safe, has a long cycle life, high capacity, and high energy density.

Process for producing non-flammable quasi-solid electrolyte and electrolyte-separator for lithium battery applications

A process for producing a highly oriented graphene film (HOGF), comprising: (a) preparing a graphene oxide (GO) dispersion having GO sheets dispersed in a fluid medium; (b) dispensing and depositing the dispersion onto a surface of a supporting substrate to form a layer of GO, wherein the dispensing and depositing procedure includes subjecting the dispersion to an orientation-inducing stress; (c) removing the fluid medium to form a dried layer of GO having an inter-plane spacing dof 0.4 nm to 1.2 nm; (d) slicing the dried layer of GO into multiple pieces of dried GO and stacking at least two pieces of dried GO to form a mass of multiple pieces of GO; and (f) heat treating the mass under an optional first compressive stress to produce the HOGF at a first heat treatment temperature higher than 100&#xb0; C. to an extent that an inter-plane spacing dis decreased to a value less than 0.4 nm.

Growing community of inventors

Huber Heights, OH, United States of America

Yanbo Wang