600 results about "Electrochemical capacitance" patented technology

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.

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.

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.

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.

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.

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.

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.

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.

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.

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 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.