309results about How to "Improve power characteristics" patented technology

A vertical GaN-based LED and a method of manufacturing the same are provided. The vertical GaN-based LED includes an n-electrode, a first n-type GaN layer, a first AlGaN layer, a GaN layer, a second AlGaN layer, a second n-type GaN layer, an active layer, a p-type GaN layer, and a structure support layer. The first n-type GaN layer has uneven patterns having a plurality of protuberances. The first AlGaN layer is formed under the first n-type GaN layer, and the GaN layer is formed under the first AlGaN layer. The active layer is formed under the second n-type GaN layer, and the p-type GaN layer is formed under the active layer. A p-electrode is formed under the p-type GaN layer, and the structure support layer is formed under the p-electrode.

The invention belongs to the fields of material synthesis and energy technology, and especially relates to a graphene/metal oxide composite cathode material for lithium ion batteries and a preparation method thereof. Grapheme is dispersed into various metal oxide precursor salt solutions; a graphene/metal oxide compound is obtained directly by a hydrothermal method, or an graphene/metal oxide compound is obtained by a liquid in-situ polymerization method or a coprecipitation process; and the graphene/metal oxide compound is obtained by heat treatment or hydrothermal treatment. In the invention, the novel three-dimensional composite cathode material of graphene-coated metal oxide or graphene-anchored metal oxide is prepared by carrying metal oxide particles with graphene as a carrier. The obtained composite material can be used as a lithium ion battery cathode, which has a high specific capacity, excellent cycle stability and rate capability, and is expected to be used as a lithium ion battery cathode material with a high energy density and a high power density.

The invention discloses a lithium-ion secondary battery and an electrolyte thereof. The electrolyte comprises a solvent, lithium salt and a film forming additive, wherein the solvent comprises a first solvent and a second solvent; the first solvent comprises linear carboxylic ester and ethylene carbonate; the second solvent is one or more of ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate and propylene carbonate; and the film forming additive is one or more of fluoroethylene carbonate, vinylene carbonate, 1,3-propane suhone, succinonitrile, adiponitrile, lithium bis(oxalato)borate, and lithium oxalyldifluoroborate. Due to the collocation of linear carboxylic ester and ethylene carbonate, a solvent system with a higher dielectric constant and low viscosity is obtained; the film forming additive improves poor compatibility between linear carboxylic ester and graphite; and finally the lithium-ion secondary battery adopting the electrolyte presents high-power discharge capacity, excellent high-temperature cycling stability and low-temperature charge and discharge properties.

A permanent magnet synchronous machine with improved torque and power characteristics. A circumferential-oriented rotor assembly is provided with alternating permanent magnets and magnetic pole pieces. In order to reduce the amount of leakage flux in the rotor and increase the effective length of the permanent magnet, a trapezoidal or otherwise tapered permanent magnet structure is used. By alternating trapezoidal permanent magnet, and magnetic pole pieces, a higher intensity magnetic field is created in the air gap utilizing the same radial space in the motor without altering the weight or volume of the motor compared to conventional machines.

The invention relates to an organic electroluminescent device; in the device, a luminescent layer comprises a substrate compound and a doped compound; a nitrogen-containing aromatic heterocyclic derivative is set between the luminescent layer and a cathode. The organic electroluminescent device has a low driving pressure, and is improved in luminous efficiency, power efficiency and service life.

A dynamo-electric machine has a stator with a primary winding and a rotor with a field magnet and a shaft. the field magnet includes a first field magnet having diferent polarity magnetic poles sequentially arranged in a rotation direction and a second field magnet having diferent polarity magnetic poles sequentially arranged in a rotation direction. The machine further has a mechanism for shifting the first and the second field magnets in axial and rotation directions.

The invention discloses a carbon nano tube/graphene composite negative pole material, a preparation method thereof and a lithium battery. The preparation method of the carbon nano tube/graphene composite negative pole material comprises the steps of placing graphene powder and a catalyst for carbon source splitting decomposition in a microwave reaction cavity, vacuumizing the microwave reaction cavity and leading protective gas into the microwave reaction cavity and using a microwave vapor deposition method to prepare the carbon nano tube/graphene composite negative pole material on a graphene base body growing carbon nano tube. A negative pole of the lithium battery contains the carbon nano tube/graphene composite negative pole material. The preparation method of the carbon nano tube/graphene composite negative pole material adopts the microwave vapor deposition method to perform in-situ preparation of the carbon nano tube/graphene composite negative pole material, does not needs a pre-synthesis process, reduces the production cost, adopts microwave heating and is efficient, low in energy consumption and short in production period. Due to the fact that the lithium battery contains the carbon nano tube/graphene composite negative pole material, embedding and taking-out of lithium are facilitated, the inreversible capacity of first-time charging and discharging is reduced, and the lithium battery is good in safety and high in power.

The invention belongs to the technical field of lithium ion battery preparation, and specifically relates to nickelic ternary anode material power lithium ion battery electrolyte and a preparation method thereof. The electrolyte consists of electrolyte lithium salt, a non-aqueous organic solvent and functional additives, wherein the functional additives comprise an alkyl nitrile additive, fluorinated chain carboxylate, a lithium salt additive and a cathode film forming additive; and the content of the functional additives is 0.5-10% of the weight of the electrolyte. The electrolyte provided bythe invention interacts with transition metal in a nickelic ternary anode material through the functional additives and is decomposed on the surfaces of the anode and cathode to form stable interfacefilms, so as to inhibit the metal ionic catalysis activity and decrease battery side reactions, so that the electrolyte has favorable anti-oxidant and film forming characteristics, is capable of effectively improving the high-temperature storage performance, safety performance and cycle life of nickelic ternary anode material power lithium ion batteries, effectively inhibiting the generation of battery expansion and ensuring the high power characteristic of the batteries at the same time.

The invention relates to a preparation method for a super capacitor, comprising the following steps: (1) placing a foam nickel substrate in a chemical gas phase deposition reacting furnace, introducing argon for 10-60 minutes, exhausting air in the furnace, then heating the furnace to 450-750 DEG C, introducing hydrocarbon gases in an argon atmosphere at a flow rate between 25ml/min and 40ml/min,reacting the mixture for 30 seconds to 50 minutes at a temperature of 450-750 DEG C, and obtaining foam nickel on which carbon nano tubes grow after finishing the reaction; (2) removing surface loosing layer products, directly using the foam nickel substrate on which the carbon nano tubes grow as electrodes of the super capacitor; and (3) drying the electrodes with same thickness and size, which are obtained from the step (2), fully soaking the electrode with electrolyte for 1-36 hours, separating a diaphragm soaked with the electrolyte and assembling the components to obtain the super capacitor; and the hydrocarbon gases are acetylene, methane, ethylene or propylene. The carbon nano tubes directly grow on the foam substrate without a binding agent; and the foam nickel is used as the substrate, the volume density of electrode substances is higher and holes are reasonably distributed.

The present invention provides a lithium-ion secondary battery whose power characteristic has been improved without widening a battery size. A cylindrical lithium-ion battery 20 accommodates a winding group 6 and a non-aqueous electrolytic solution within a battery container 7. The winding group 6 is structured by winding a positive electrode using lithium manganate (Li1+xMn2-xO4 or Li1+xMn2-x-yAlyO4) where an average particle diameter of primary particles is in a range of from 0.1 mum to 2 mum as a positive electrode active material and a negative electrode using amorphous carbon as a negative electrode active material via a separator. The reaction area of the positive electrode active material is optimized.

An additive for an electrolyte solution includes a lithium salt having an oxalato complex as an anion and a compound represented by following Chemical Formula 1.

Wherein, a represents C or Si, b represents H or F, and n represents an integer of 1 to 5. A non-aqueous electrolyte solution including the additive and a lithium secondary battery including the electrolyte solution also are provided.

A method for preparing a slurry for forming a catalyst layer of a PEM fuel cell electrode and a method for fabricating the PEM fuel cell produced thereby are provided. The method for preparing a slurry for forming a catalyst layer of a proton exchange membrane (PEM) fuel cell according to the present invention comprises the steps of (a) adding an MOH solution to a perfluorosulfonate ionomer (PFSI) solution to convert PFSI in the PFSI solution into an M+ form-PFSI solution, wherein M is an alkaline metal selected from the group consisting of Li, Na and K; (b) adding an organic polar solvent having a higher boiling point than that of alcohol remaining in the PFSI solution to a mixed solution obtained in step (a) and heating the mixture at a temperature range of the boiling point of the alcohol to 20° C. higher than the boiling point to remove the remaining alcohol to obtain a pretreated PFSI solution; and (c) mixing the pretreated PFSI solution with Pt/C to form a slurry for forming a catalyst layer of a PEM fuel cell. Since processing stability is improved and the slurry can be easily prepared, Pt loading greater than a conventional level can be achieved by a single coating step by preventing a Pt catalyst from penetrating into a backing layer, the electrode characteristics are improved. Also, mass production of the PEM fuel cells is possible.

The present invention provides a cathode active material for a nonaqueous electrolyte secondary battery with a high capacity, high stability and excellent output characteristics and a method for producing the same, and a nonaqueous electrolyte secondary battery using the cathode active material.

The cathode active material for a nonaqueous electrolyte secondary battery is represented by a general formula: Li_tNi_1.x.y.zCo_xAl_yTi_zO₂ wherein 0.98≦t≦1.10, 0<x≦0.30, 0.03≦y≦0.15, 0.001≦z≦0.03; and includes a hexagonal lithium-containing composite oxide with a layer structure of secondary particles having primary particles, in which a titanium-enriched layer is formed on a surface of the primary particles and/or a grain boundary between the primary particles. The titanium-enriched layer on the surface of the primary particles and/or a grain boundary between the primary particles serves as a lithium ion conductor, yielding smooth extraction and insertion of lithium ions. Accordingly, the secondary battery with a high capacity, high stability and excellent output characteristics can be produced when a positive electrode is formed with the lithium nickel composite oxide as a cathode active material.

The invention discloses a method for preparing a nitrogen-enriched porous carbon material for a supercapacitor by taking lignite as the raw material and belongs to the technical field of new energy. The method comprises the following steps: smashing the lignite, washing by deionized water to remove the surface impurities, washing and baking, heating up to a pre-carbonization temperature in an inert gas at the speed of 1-10 DEG C/min, and keeping the temperature for 2h to obtain the carbon precursor; grinding the carbon precursor, uniformly mixing with the alkali metal hydroxide, putting into the inert gas, heating up to an activation temperature in the inert gas at the speed of 1-10 DEG C/min, and keeping the temperature for 1-10h to obtain the activation product; and performing acid pickling and neutralization on the activation product, washing to be neutral by deionized water, drying and grinding to obtain the nitrogen-enriched porous carbon material for the supercapacitor. The high-performance nitrogen-enriched porous carbon material for the supercapacitor can be prepared from the lignite so that the nitrogen-enriched porous carbon material is excellent in performance, energy-saving, environmentally friendly, simple in process and low in cost and has a wide industrial application prospect by being used as the supercapacitor electrode material.

The invention relates to a supercapacitor flexible self-supporting full-carbon electrode with graphene as a binder. The electrode is composed of two components of a micro-grade porous carbon materialand the graphene, and the thickness is 10-200 [mu]m, wherein the ratio of the porous carbon particle with dimension of 2-10 [mu]m as the active material in the total electrode mass is 80-95%. The ratio of the graphene with dimension of 3-15 [mu]m and slice layer thickness of 1-5 as the binder in the total electrode mass is 5-20%. The whole electrode has high flexibility and can be directly used asthe electrode of the flexible supercapacitor. The invention further provides a preparation method of the carbon electrode, wherein the preparation method comprises the steps of dispersing the porouscarbon into graphene oxide solution, performing vacuum pumping and filtering on the mixed solution for forming a film, and finally performing high-temperature thermal treatment on the composite film of the porous carbon and the graphene oxide through protection of an inert atmosphere, thereby converting the graphene oxide to graphene through reduction reaction, thereby obtaining the porous carbonmaterial/graphene flexible self-supporting composite film electrode. In the electrode, the porous carbon is the active material, and the graphene is used as the binder, a conductive agent and an auxiliary active material. Compared with a traditional electrode forming method in which insulating high-molecular materials such as PTFE and PVDF are used as the binder, the carbon electrode which is prepared through using the graphene as a multifunctional conductive binder has higher specific capacity and better multiplying power performance. Furthermore the electrode forming method has advantages ofsimple operation and environment-friendly performance.

A zinc oxide nanometer fiber cathode material for lithium ion battery and a preparation method thereof belong to the technical fields of high polymer material and chemical power source. The zinc oxide nanometer fiber material for lithium ion battery provided by the invention has large specific surface area. The method first prepares composite nanometer fiber by electrospinning, and then the nanometer fiber is subjected to high-temperature calcination to obtain the zinc oxide nanometer fiber. The preparation process provided by the invention is simple and easy to control, and has low production cost. The cathode electrode material for lithium ion battery provided by the invention overcomes the disadvantages of zinc oxide nanorod prepared by other methods as cathode material for lithium ion battery, such as low first cycling efficiency, weak cycle stability and high-rate discharge ability. The invention provides a zinc oxide nanometer fiber cathode material for lithium ion battery and the preparation method thereof. The material has high initial discharge capacity and cycling stability, improves high power characteristic and high-rate discharge capacity of cathode material, and is suitable for development requirements of lithium ion power battery for electric vehicles.