606 results about "Electrochemical capacitance" patented technology

Graphitic nanofibers, which include tubular fullerenes (commonly called "buckytubes"), nanotubes and fibrils, which are functionalized by chemical substitution, are used as electrodes in electrochemical capacitors. The graphitic nanofiber based electrode increases the performance of the electrochemical capacitors. Preferred nanofibers have a surface area greater than about 200 m2 / gm and are substantially free of micropores.

A method of producing a composite electrode having a specific surface area of at least 100 m2 / gm for use in an electrochemical capacitor. The method comprises (a) providing exfoliated graphite flakes that are substantially interconnected to form a porous, conductive graphite network comprising pores; and (b) incorporating an electrochemically active material into at least a pore of the graphite network to form the composite electrode. The exfoliated graphite flakes are preferably obtained from the intercalation and exfoliation of a laminar graphite material selected from natural graphite, spheroidal graphite, synthetic graphite, highly oriented pyrolytic graphite, meso-carbon micro-bead, carbon / graphite fiber, carbon / graphite whisker, carbon / graphite nano-fiber, carbon nano-tube, or a combination thereof. A supercapacitor featuring such a composite electrode exhibits an exceptionally high capacitance value and low equivalent series resistance.

A composite electrode is created by forming a thin conformal coating of mixed metal oxides on a highly porous carbon structure. The highly porous carbon structure performs a role in the synthesis of the mixed oxide coating and in providing a three-dimensional, electronically conductive substrate supporting the thin coating of mixed metal oxides. The metal oxide mixture shall include two or more metal oxides. The composite electrode, a process for producing said composite electrode, an electrochemical capacitor and an electrochemical secondary (rechargeable) battery using said composite electrode are disclosed.

A negative electrode material comprises a conductive powder of particles of a lithium ion-occluding and releasing material coated on their surface with a graphite coating. The graphite coating, on Raman spectroscopy analysis, develops broad peaks having an intensity I1330 and I1580 at 1330 cm−1 and 1580 cm−1 Raman shift, an intensity ratio I1330 / I1580 being 1.5<I1330 / I1580<3.0. Using the negative electrode material, a lithium ion secondary battery having a high capacity and improved cycle performance can be manufactured.

The present invention relates to a material for use as an electrode for electrochemical energy storage devices such as electrochemical capacitors (ECs) and secondary batteries, primary batteries, metal / air batteries, fuel cells, flow batteries and a method for producing the same. More specifically, this invention relates to an electrode material consisting of a functionalized porous carbon, a method for producing the same, and an energy storage device using said electrode materials.

Particles of a silicon oxide of formula: SiOx wherein x is 0.5 to 1.6, a silicon composite comprising silicon dispersed in silicon dioxide and having a molar ratio Si / O from 1:0.5 to 1:1.6, or a mixture thereof are doped with 50-100,000 ppm of phosphorus. A negative electrode material comprising the phosphorus-doped particles is suited for use in non-aqueous electrolyte secondary batteries. A lithium ion secondary battery having satisfactory cycle and rate properties is obtainable.

A composite having an electroactive polymer coating on a porous carbon structure is disclosed. The composite may be used in capacitor electrodes. The composite may be made by self-limiting electropolymerization of a monomer on the carbon structure.

Composite electrodes comprising carbon nanofibers (fibrils) and an electrochemically active material are provided for use in electrochemical capacitors. The fibril composite electrodes exhibit high conductivity, improved efficiency of active materials, high stability, easy processing, and increase the performance of the capacitor. A method for producing the composite electrodes for use in electrochemical capacitors is also provided.

A method and apparatus for forming a reliable and cost efficient battery or electrochemical capacitor electrode structure that has an improved lifetime, lower production costs, and improved process performance are provided. In one embodiment a method for forming a three dimensional porous electrode for a battery or an electrochemical cell is provided. The method comprises depositing a columnar metal layer over a substrate at a first current density by a diffusion limited deposition process and depositing three dimensional metal porous dendritic structures over the columnar metal layer at a second current density greater than the first current density.

An electrode material is created by forming a thin coating or small deposits of metal oxide as an intercalation host on a carbon powder. The carbon powder performs a role in the synthesis of the oxide coating, in providing a three-dimensional, electronically conductive substrate supporting the metal oxide, and as an energy storage contribution material through ion adsorption or intercalation. The metal oxide includes one or more metal oxides. The electrode material, a process for producing said electrode material, an electrochemical capacitor and an electrochemical secondary (rechargeable) battery using said electrode material is disclosed.

A hybrid lead-acid battery / electrochemical capacitor electrical energy storage device. The lead-acid battery and electrochemical capacitor reside in the same case and are electrically connected. Preferably, a hybrid device of the present invention includes at least one non-polarizable positive electrode, at least one non-polarizable negative electrode, and at least one polarizable electric double layer negative electrode. Separators reside between the electrodes and the separators and electrodes are impregnated with an aqueous sulfuric acid electrolyte. A hybrid device of the present invention exhibits high power characteristics.

Methods of oxidizing multiwalled carbon nanotubes are provided. The multiwalled carbon nanotubes are oxidized by contacting the carbon nanotubes with gas-phase oxidizing agents such as CO2, O2, steam, N2O, NO, NO2, O3, and ClO2. Near critical and supercritical water can also be used as oxidizing agents. The multiwalled carbon nanotubes oxidized according to methods of the invention can be used to prepare rigid porous structures which can be utilized to form electrodes for fabrication of improved electrochemical capacitors.

Disclosed herein are an activated carbon in which pores with pore sizes of 0.3˜5 nm account for 80% or higher based on an overall pore volume, a method for preparing the activated carbon, and an electrochemical capacitor including the activated carbon, so that, since the activated carbon has uniform sized fine pores, high-rate discharge characteristics, high-rate charging and discharging characteristics, and low-temperature characteristics can be improved; since the content of functional groups on the surface of the activated carbon is low, there can be provided a supercapacitor and a lithium ion capacitor, having improved high voltage and lifespan characteristics; and the time for preparing an active material can be significantly shortened and thus the material cost and the process cost can be remarkably reduced.

Graphitic nanofibers, which include tubular fullerenes (commonly called "buckytubes"), nanotubes and fibrils, which are functionalized by chemical substitution, are used as electrodes in electrochemical capacitors. The graphitic nanofiber based electrode increases the performance of the electrochemical capacitors.

An energy buffer including an electrochemical capacitor can be added to the primary circuit and / or to the secondary circuit of in-motion wireless power transfer system. The energy buffer(s) can smoothen the power delivered by the power grid and captured by a vehicle passing over an array of transmit coils through in-motion wireless power transfer. The reduction in the transient power transfer can reduce the peak current that flows through various components of the in-motion wireless power transfer system including a vehicle battery on the vehicle, and prolong the life of the in-motion wireless power transfer system.

A current collector for use in a capacitor having an aqueous or non-aqueous electrolyte, such as an aqueous sulfuric acid electrolyte. The conductive basis of the current collector may be manufactured from a number of conductive metals but, preferably, is comprised of lead or a lead alloy. The portion of the conductive basis that will be in contact with the electrolyte is provided with a protective layer that is created by deposition of one or more layers of one or more protective coating materials thereto. Each protective coating material is comprised of at least a conductive carbon powder and a polymer binder that is resistant to the electrolyte. Preferably, but not essentially, the protective coating material(s) are applied to the conductive basis in the form of a paste, which is subsequently subjected to a solvent evaporation step and a thermal treatment step. The resulting protective layer is also substantially devoid of pores through which the electrolyte can permeate.

The invention relates to a porous carbon material and a preparation method and application thereof. Organic and inorganic materials in shrimp shell and crab shell are used as carbon sources and natural templates, meanwhile the pore formation effect of template structures during high temperature decomposition is utilized, and a proper activator is mixed to produce the porous carbon material. The difficulties of methods those in the prior art in a preparation process, preparation of templates is needed, carbon precursors need to be soak in the templates, and the like, are overcome; and the nitrogen-containing carbon material with multistage pore structures is prepared by using the characteristic that the carbon sources themselves contain nitrogen element. The preparation method of the porous carbon material is simple, is low in cost, is strong in process controllability, and is suitable for industrial production, the porous carbon material shows very good application effects in electrochemical capacitors and secondary cells, and the porous carbon material not only provides a new material for the new energy, but also opens up a new way for the effective use of waste, namely the shrimp shell and crab shell in aquatic products industry.

A method of producing a composite electrode having a specific surface area of at least 100 m2 / gm for use in an electrochemical capacitor. The method comprises (a) providing exfoliated graphite flakes that are substantially interconnected to form a porous, conductive graphite network comprising pores; and (b) incorporating an electrochemically active material into at least a pore of the graphite network to form the composite electrode. The exfoliated graphite flakes are preferably obtained from the intercalation and exfoliation of a laminar graphite material selected from natural graphite, spheroidal graphite, synthetic graphite, highly oriented pyrolytic graphite, meso-carbon micro-bead, carbon / graphite fiber, carbon / graphite whisker, carbon / graphite nano-fiber, carbon nano-tube, or a combination thereof. A supercapacitor featuring such a composite electrode exhibits an exceptionally high capacitance value and low equivalent series resistance.

Cohesive carbon assemblies are prepared by obtaining a functionalized carbon starting material in the form of powder, particles, flakes, loose agglomerates, aqueous wet cake, or aqueous slurry, dispersing the carbon in water by mechanical agitation and / or refluxing, and substantially removing the water, typically by evaporation, whereby the cohesive assembly of carbon is formed. The method is suitable for preparing free-standing, monolithic assemblies of carbon nanotubes in the form of films, wafers, discs, fiber, or wire, having high carbon packing density and low electrical resistivity. The method is also suitable for preparing substrates coated with an adherent cohesive carbon assembly. The assemblies have various potential applications, such as electrodes or current collectors in electrochemical capacitors, fuel cells, and batteries, or as transparent conductors, conductive inks, pastes, and coatings.

A composite composition for use in an electrode for electrochemical capacitors, comprising: (a) an electrochemically active material; and (b) exfoliated graphite flakes that are substantially interconnected to form a porous, conductive graphite network comprising pores, wherein at least a portion of the active material resides in a pore of the network. The composite composition is characterized by having liquid accessible pores which provide a surface area greater than about 200 m2 / gm, preferably greater than 500 m2 / gm, more preferably greater than 1000 m2 / gm, and most preferably greater than 1000 m2 / gm. Also disclosed is a capacitor that includes at least an electrode comprising such a composite composition. A supercapacitor featuring such a composite electrode exhibits an exceptionally high capacitance value and high electrical conductivity.

The present invention provides an improved supercapacitor-like electronic battery comprising a conventional electrochemical capacitor structure. A first nanocomposite electrode and a second electrode and an electrolyte are positioned within the conventional electrochemical capacitor structure. The electrolyte separates the nanocomposite electrode and the second electrode. The first nanocomposite electrode has first conductive core-shell nanoparticles in a first electrolyte matrix. A first current collector is in communication with the nanocomposite electrode and a second current collector is in communication with the second electrode. Also provided is an electrostatic capacitor-like electronic battery comprising a high dielectric-strength matrix separating a first electrode from a second electrode and, dispersed in said high-dielectric strength matrix, a plurality of core-shell nanoparticles, each of said core-shell nanoparticles having a conductive core and an insulating shell.

A negative electrode material comprises a conductive powder of particles of a lithium ion-occluding and releasing material coated on their surface with a graphite coating. The graphite coating, on Raman spectroscopy analysis, develops broad peaks having an intensity I 1330 and I 1580 at 1330 cm -1 and 1580 cm -1 Raman shift, an intensity ratio I 1330 / I 1580 being 1.5 < I 1330 / I 1580 < 3.0. Using the negative electrode material, a lithium ion secondary battery having a high capacity and improved cycle performance can be manufactured.

The invention relates to a porous carbon electrode materials and the preparation method, belonging to the electrochemistry and the novel energy source materials, wherein the porous carbon electrode materials adopt the template carbonization and the method combined with the CO2 post-processing using the meso-porous oxide silicon as the remplate, and the cane sugar, furfuryl alcohol, polyacrylonitrile and the like as the precursors, through the technology steps of the liquid phase impregnation, the high temperature carbonization and the template removal and the like, then combines high temperature process, obtaining the super capacitor porous carbon electrode materials. The porous carbon electrode materials prepared by the method has high surface area, large pore volume, adjustable pore structure and multilevel-microporous pore structure, wherein the pore channel is composed of a meso-porous of 2-5 nm and the microporous with the meso-porous wall of 0.1-2 nm, so the electrochemistry capacity of the prepared porous carbon electrode is marked increased, and the integral property of good.

An electrode material is created by forming a thin conformal coating of metal oxide on a highly porous carbon meta-structure. The highly porous carbon meta-structure performs a role in the synthesis of the oxide coating and in providing a three-dimensional, electronically conductive substrate supporting the thin coating of metal oxide. The metal oxide includes one or more metal oxides. The electrode material, a process for producing said electrode material, an electrochemical capacitor and an electrochemical secondary (rechargeable) battery using said electrode material is disclosed.

A carbon nanotube composite includes a free-standing carbon nanotube structure and an amount of reinforcements. The free-standing carbon nanotube structure includes an amount of carbon nanotubes. The reinforcements are located on the carbon nanotubes and combining the carbon nanotubes together.

Silicon particles are irradiated with neutrons so that 30Si of silicon isotopes is transformed to 31P through nuclear reaction. A negative electrode material comprising the P-doped silicon powder exhibits good cycle performance of silicon and is endowed with a high conductivity while maintaining the high initial efficiency and high battery capacity of silicon, and is thus useful as an active material in a negative electrode of a non-aqueous electrolyte secondary battery.

A conductive powder is provided in which particles having silicon crystallites dispersed in a silicon compound are coated on their surface with carbon. The conductive powder develops a diffraction peak assigned to Si(111) around 2θ=28.4° on x-ray diffractometry (Cu—Kα) using copper as the counter cathode, the peak having a half width of at least 1.0°, and has a specific resistance of up to 50 mΩ. The powder is used as a negative electrode material to construct a non-aqueous electrolyte secondary battery, which has a high charge / discharge capacity and improved cycle performance.