Dayton, OH, United States
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Patent
Nanotek Instruments, Inc. | Date: 2016-11-17

A process for producing a transparent conductive film, comprising (a) providing a graphene oxide gel; (b) dispersing metal nanowires in the graphene oxide gel to form a suspension; (c) dispensing and depositing the suspension onto a substrate; and (d) removing the liquid medium to form the film. The film is composed of metal nanowires and graphene oxide with a metal nanowire-to-graphene oxide weight ratio from 1/99 to 99/1, wherein the metal nanowires contain no surface-borne metal oxide or metal compound and the film exhibits an optical transparence no less than 80% and sheet resistance no higher than 300 ohm/square. This film can be used as a transparent conductive electrode in an electro-optic device, such as a photovoltaic or solar cell, light-emitting diode, photo-detector, touch screen, electro-wetting display, liquid crystal display, plasma display, LED display, a TV screen, a computer screen, or a mobile phone screen.


Patent
Nanotek Instruments, Inc. | Date: 2016-11-17

A unitary graphene layer or graphene single crystal containing closely packed and chemically bonded parallel graphene planes having an inter-graphene plane spacing of 0.335 to 0.40 nm and an oxygen content of 0.01% to 10% by weight, which unitary graphene layer or graphene single crystal is obtained from heat-treating a graphene oxide gel at a temperature higher than 100 C., wherein the average mis-orientation angle between two graphene planes is less than 10 degrees, more typically less than 5 degrees. The molecules in the graphene oxide gel, upon drying and heat-treating, are chemically interconnected and integrated into a unitary graphene entity containing no discrete graphite flake or graphene platelet. This graphene monolith exhibits a combination of exceptional thermal conductivity, electrical conductivity, mechanical strength, surface smoothness, surface hardness, and scratch resistance unmatched by any thin-film material of comparable thickness range.


Patent
Nanotek Instruments, Inc. | Date: 2017-02-08

Disclosed is a process for producing graphene-silicon nanowire hybrid material, comprising: (A) preparing a catalyst metal-coated mixture mass, which includes mixing graphene sheets with micron or sub-micron scaled silicon particles to form a mixture and depositing a nano-scaled catalytic metal onto surfaces of the graphene sheets and/or silicon particles; and (B) exposing the catalyst metal-coated mixture mass to a high temperature environment (preferably from 300 C. to 2,000 C., more preferably from 400 C. to 1,500 C., and most preferably from 500 C. to 1,200 C.) for a period of time sufficient to enable a catalytic metal-catalyzed growth of multiple silicon nanowires using the silicon particles as a feed material to form the graphene-silicon nanowire hybrid material composition. An optional etching or separating procedure may be conducted to remove catalytic metal or graphene from the Si nanowires.


A flexible, asymmetric electrochemical cell comprising: (A) A sheet of graphene paper as first electrode comprising nano graphene platelets having a platelet thickness less than 1 nm, wherein the first electrode has electrolyte-accessible pores; (B) A thin-film or paper-like first separator and electrolyte; and (C) A thin-film or paper-like second electrode which is different in composition than the first electrode; wherein the separator is sandwiched between the first and second electrode to form a flexible laminate configuration. The asymmetric supercapacitor cells with different NGP-based electrodes exhibit an exceptionally high capacitance, specific energy, and stable and long cycle life.


Patent
Nanotek Instruments, Inc. | Date: 2017-03-31

Multi-functional and high-performing fabric comprising a first layer of yarns woven to form the fabric wherein the yarns comprise at least one unitary graphene-based continuous graphitic fiber comprising at least 90% by weight of graphene planes that are chemically bonded with one another having an inter-planar spacing d_(002 )from 0.3354 nm to 0.4 nm as determined by X-ray diffraction and an oxygen content less than 5% by weight. A majority of the graphene planes in such a continuous graphitic fiber are parallel to one another and parallel to a fiber axis direction. The graphitic fiber contains no core-shell structure, has no helically arranged graphene domains or domain boundaries, and has a porosity level less than 5% by volume, more typically less than 2%, and most typically less than 1% (practically pore-free).


Liu C.,Nanotek Instruments, Inc. | Liu C.,Dalian University of Technology | Yu Z.,Angstron Materials, Inc | Neff D.,Nanotek Instruments, Inc. | And 2 more authors.
Nano Letters | Year: 2010

A supercapacitor with graphene-based electrodes was found to exhibit a specific energy density of 85.6 Wh/kg at room temperature and 136 Wh/kg at 80 °C (all based on the total electrode weight), measured at a current density of 1 A/g. These energy density values are comparable to that of the Ni metal hydride battery, but the supercapacitor can be charged or discharged in seconds or minutes. The key to success was the ability to make full utilization of the highest intrinsic surface capacitance and specific surface area of single-layer graphene by preparing curved graphene sheets that will not restack face-to-face. The curved morphology enables the formation of mesopores accessible to and wettable by environmentally benign ionic liquids capable of operating at a voltage >4 V. © 2010 American Chemical Society.


Jang B.Z.,Nanotek Instruments, Inc. | Liu C.,Nanotek Instruments, Inc. | Neff D.,Nanotek Instruments, Inc. | Yu Z.,Angstron Materials, Inc | And 4 more authors.
Nano Letters | Year: 2011

Herein reported is a fundamentally new strategy for the design of high-power and high energy-density devices. This approach is based on the exchange of lithium ions between the surfaces (not the bulk) of two nanostructured electrodes, completely obviating the need for lithium intercalation or deintercalation. In both electrodes, massive graphene surfaces in direct contact with liquid electrolyte are capable of rapidly and reversibly capturing lithium ions through surface adsorption and/or surface redox reaction. These devices, based on unoptimized materials and configuration, are already capable of storing an energy density of 160 Wh/kgcell, which is 30 times higher than that (5 Wh/kgcell) of conventional symmetric supercapacitors and comparable to that of Li-ion batteries. They are also capable of delivering a power density of 100 kW/kgcell, which is 10 times higher than that (10 kW/kgcell) of supercapacitors and 100 times higher than that (1 kW/kgcell) of Li-ion batteries. © 2011 American Chemical Society.


Grant
Agency: National Science Foundation | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 149.99K | Year: 2010

This Small Business Innovation Research Phase I project seeks to develop a new generation of anode materials for lithium-ion batteries having the advantages of low cost, high Li+ ion storage capacity, high rate, and long cycling life. These anode materials are innovative nanocomposite structures made up of Si nano particles, carbon, and nano graphene platelets (NGPs). NGPs were recently shown to exhibit the highest intrinsic strength among existing materials. This reasearch aims to demonstrate the technical feasibility of this electrode technology by carrying out the following tasks: (1) preparation and characterization of the nanocomposite particles based on theoretical guidelines, and (2) cycling performance evaluation of laboratory-scale cells. The goal is the development of an anode material with a capacity over 700 mAh/g. The broader/commercial impact of this project is that the availability of a high-capacity and high-rate anode material will overcome one of the barriers that have prevented the more widespread implementation of Li-ion batteries in electric vehicle applications. If successful, the new anode technology is expected to speed the development and deployment of advanced lithium-ion batteries for electric vehicles. The batteries that use this anode material will have enhanced the charge/discharge rates and enable electric vehicles with higher mileage range. The technology is expected to have positive impact in several of the nation's energy-related initiatives: reduction of greenhouse gas and other emissions, and decrease in dependence on imported fossil fuel. Moreover, the successful commercialization of this technology is expected to provide a differentiating capability that can strengthen Li-ion battery development and manufacturing within the US.


Grant
Agency: NSF | Branch: Standard Grant | Program: | Phase: | Award Amount: 463.41K | Year: 2011

This Small Business Innovation Research (SBIR) Phase II project aims to develop cost-effective and commercializable anode materials exhibiting large lithium storage capacity, high rate capability, and long cycle life for next generation lithium-ion batteries. Silicon-based anode materials hold great potential to meet the high energy density requirements for advanced lithium ion batteries. However, the intrinsic low electrical conductivity and huge volume change of silicon during lithium insertion and extraction lead to quick electrode failure, and thus hindering their practical applications. The proposed Si nanocomposites are expected to effectively prevent the crumbling of Si particles, maintain the integrity of the electron-conducting network, and allow the electrolyte solution to easily access the active sites. This phase II project will develop and optimize the nanocomposite compositions and related synthesis and processing procedure to accelerate industrial scale manufacturing of anode materials in the US.

The broader impact/commercial potential of this project is the development of a new anode technology capable of exploiting a dramatic improvement in lithium ion battery performance, which will speed the deployment of advanced lithium ion batteries for plug-in hybrid electric vehicles and all electric vehicles.


Grant
Agency: National Science Foundation | Branch: | Program: SBIR | Phase: Phase II | Award Amount: 463.41K | Year: 2012

This Small Business Innovation Research (SBIR) Phase II project aims to develop cost-effective and commercializable anode materials exhibiting large lithium storage capacity, high rate capability, and long cycle life for next generation lithium-ion batteries. Silicon-based anode materials hold great potential to meet the high energy density requirements for advanced lithium ion batteries. However, the intrinsic low electrical conductivity and huge volume change of silicon during lithium insertion and extraction lead to quick electrode failure, and thus hindering their practical applications. The proposed Si nanocomposites are expected to effectively prevent the crumbling of Si particles, maintain the integrity of the electron-conducting network, and allow the electrolyte solution to easily access the active sites. This phase II project will develop and optimize the nanocomposite compositions and related synthesis and processing procedure to accelerate industrial scale manufacturing of anode materials in the US. The broader impact/commercial potential of this project is the development of a new anode technology capable of exploiting a dramatic improvement in lithium ion battery performance, which will speed the deployment of advanced lithium ion batteries for plug-in hybrid electric vehicles and all electric vehicles.

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