214 results about "Natural graphite" patented technology

The invention relates to the technical field of flux-cored wires. The preparation method comprises the following steps: weighing the following raw materials in parts by weight: 4-6 parts of chromium carbide powder, 7-9 parts of molybdenum powder, 6-8 parts of nickel powder, 10-15 parts of niobium powder, 15-18 parts of tungsten carbide powder, 7-11 parts of a modified titanium carbide agent, 5-8 parts of a blending agent added based on boron and 2-4 parts of 30-mesh natural graphite; 1-2 parts of sodium fluosilicate; 1-2 parts of aluminum powder; and 70-75 parts of iron powder. The flux-cored wire can adapt to complex service environments of parts such as rollers and continuous casting crystallizers in the metallurgical industry, the service life of the parts subjected to surfacing repair is prolonged, the production efficiency of the parts subjected to surfacing repair is improved, the obtained flux-cored wire achieves balance of high-temperature performance, mechanical performance and low-temperature stability, and the comprehensive applicability of products is improved.

The invention discloses fast charge graphite, a preparation method thereof and a lithium ion battery negative electrode material, and the preparation method comprises the following steps: carrying out acid leaching elution and alkali liquor neutralization on natural graphite fine powder to passivate the surface of the natural graphite fine powder; mixing the passivated graphite fine powder with boric acid and acetic acid, and then carrying out heating reaction to obtain modified graphite fine powder; mixing the modified graphite fine powder with a binder, and granulating to obtain secondary particles; after the secondary particles are subjected to graphitization treatment, the graphitized secondary particles are coated with a carbon source coating agent, and then carbonization treatment is conducted in the inert atmosphere; and carrying out vacuum impregnation on the carbonized secondary particles in a lithium source solution, and drying to obtain the lithium ion battery positive electrode material. The preparation method has the advantages that the interlayer spacing of the natural graphite can be expanded by modifying the natural graphite fine powder, and then the natural graphite is subjected to granulation, graphitization and carbon coating treatment and then is subjected to gradient coating, so that the prepared fast-charging graphite has more excellent dynamic performance.

The application discloses a kind of negative active material and its application.A kind of negative active material, including carbon material and silicon-based material;The carbon material includes artificial graphite, natural graphite, soft carbon, hard carbon, mesophase carbon microsphere, at least one in graphene;The chemical formula of the silicon-based material is X a Si b Y c Wherein, X includes at least one of P, As, Se, B, Ga, Mg, Al, Zn, Li, Y includes at least one of O, C, a, b, c satisfy 0≤a≤8, 0≤c≤10, 1≤(a+b)≤10, 2≤(b+c)≤10.The application has the advantages of improving the energy density, rate performance and cycle performance of lithium battery.

One aspect of the present invention provides a precursor for a negative electrode material of a lithium secondary battery, the negative electrode material prepared from the precursor, and a method for preparing the same, the precursor for the negative electrode material having high capacity characteristics, excellent processability, and excellent lifespan characteristics by a structure in which natural graphite fine powder is distributed in high-hardness artificial graphite.

The present application relates to the technical field of secondary batteries. Disclosed are a negative electrode material, a negative electrode sheet and a secondary battery. The negative electrode material comprises natural graphite and amorphous carbon filled into pores of the natural graphite. The particle hardness of the negative electrode material is 0.28-0.4 GPa, and the elastic modulus thereof is 7.0-8.0 GPa. When the compaction density of a tablet of the negative electrode material is 1.5 g / cm3 to 2.0 g / cm3, the orientation OI value of the tablet of the negative electrode material is y, and 4<y≤11. When the negative electrode material is applied to a secondary battery, the initial coulombic efficiency and the cycling stability can be significantly improved.

A method of preparing a negative electrode which includes preparing a negative electrode structure including expanded natural graphite, impregnating the negative electrode structure with a pre-lithiation solution to form an impregnated negative electrode structure, and pre-lithiating the impregnated negative electrode structure by electrochemically charging the impregnated negative electrode structure to 10% to 20% of charge capacity of the negative electrode structure.

The present invention relates to a negative electrode active material, a negative electrode for a lithium secondary battery, including same, and a lithium secondary battery. The negative electrode active material includes a silicon-based active material; and graphite, wherein the graphite includes natural graphite and artificial graphite, an absolute value of a ratio of a difference in average particle diameter (D50) size of the natural graphite with respect to the artificial graphite is 10% or less, and an absolute value of a ratio of a difference in average particle diameter (D50) size of the silicon-based active material with respect to the artificial graphite is 40% or less.

The application provides a high-rate long-cycle natural graphite-based composite negative electrode material and a preparation method and application thereof. The natural graphite-based composite negative electrode material has the characteristics of high-rate performance, low volume expansion performance and long-cycle performance. Firstly, submicron flake graphite particles are granulated into particles with a pore structure in a form of spray granulation; then, heat treatment is performed under a protective atmosphere to convert pitch into amorphous carbon; then, chemical vapor deposition technology is adopted to uniformly distribute nano titanium in the pore structure between the submicron flake graphite inside the spherical graphite particles and on the surface of the spherical graphite particles; subsequently, the nano titanium is converted into titanium nitride through nitriding treatment, that is, titanium nitride is deposited in the pore structure between the submicron flake graphite inside the spherical graphite particles and on the surface of the spherical graphite particles, to prepare the natural graphite-based composite negative electrode material.

The invention relates to a carbon graphite sealing material and a preparation method thereof, and belongs to the technical field of mechanical sealing materials, the sealing material comprises the following components: natural graphite powder and phenolic resin powder, and the mass part ratio of the natural graphite powder to the phenolic resin powder is 1: (0.2-0.4). The hardness of the material is not lower than 70 HSD, and the volume density of the carbon-graphite sealing material is not lower than 1.70 g / cm < 3 >. The sealing material is tested on a pump, and the abrasion loss does not exceed 0.1 mu m after 200 hours. The preparation method of the material comprises the following steps: fully mixing natural graphite powder and phenolic resin powder in a V-shaped mixer, and kneading the obtained mixed powder in a kneading machine to obtain a kneaded paste; and crushing the kneaded paste, carrying out hot press molding, and curing in a drying oven to obtain the carbon-graphite sealing material. The preparation process is simple, the production cost is low, the service performance of the obtained material is greatly improved, and the service life is greatly prolonged.

The invention provides a viscous damping device based on efficient heat dissipation, and belongs to the field of building anti-seismic equipment. The damper comprises a viscous damping assembly, an upper gusset plate and a lower gusset plate, the viscous damping assembly comprises a cylinder body, a piston rod, two bushings and a piston, the upper gusset plate is hinged to the end, located outside the cylinder body, of the piston rod, an upper mounting plate is fixedly mounted at the top of the upper gusset plate, and a connecting body is fixedly mounted at the end, away from the upper gusset plate, of the cylinder body; the lower gusset plate is hinged to the end, away from the cylinder body, of the connecting body, a plurality of heat conduction rods distributed in an annular array are slidably installed on the piston in a penetrating mode, and a plurality of natural graphite flakes are fixedly installed on the positions, close to the two ends, of the outer walls of the heat conduction rods. The viscous damping device based on efficient heat dissipation has the advantages that an efficient passive heat dissipation link is arranged in the cylinder body, active one-way auxiliary heat dissipation can be achieved, a heat dissipation fin convenient disassembly and maintenance structure is arranged, and the telescopic amplitude of the piston rod can be accurately recorded.

A negative electrode active substance layer of a negative electrode for nonaqueous electrolyte secondary battery herein disclosed includes at least a first negative electrode active substance and a second negative electrode active substance. The first negative electrode active substance is configured with an aggregated body of a scaly graphite whose surface of at least one part is covered with a low crystalline carbon. A graphite interlayer distance of the low crystalline carbon is equal to or more than 3.8 Å and not more than 5.0 Å. The second negative electrode active substance is a natural graphite or an artificial graphite whose graphite interlayer distance based on electron diffraction images by the transmission electron microscope is equal to or more than 3.35 Å and not more than 3.4 Å. Here, a mass ratio of the first negative electrode active substance and the second negative electrode active substance is 50:50 to 90:10.

The application provides a modification method of natural graphite, modified natural graphite and a lithium ion battery, and the modification method comprises the following steps: mixing unpurified natural graphite and a composite modifier, and performing reaction to obtain modified natural graphite; the composite modifier comprises any one or a combination of at least two of a composite strong oxidizing acid, a strong oxidizing gas or an ionic liquid; and the composite strong oxidizing acid comprises at least two strong oxidizing acids. The application provides a method which is low in cost, simple in process and capable of achieving the same oxidation treatment effect, the method combines the natural graphite purification process and the oxidation treatment process into one-step modification, thereby reducing the process, improving the production efficiency, achieving the purpose of reducing the cost, and the modified graphite has excellent initial efficiency and cycle stability.

The application belongs to the technical field of lithium ion battery cathode material, and particularly relates to a preparation device and method of graphene-coated lithium manganese iron phosphate cathode material, which comprises a graphene oxide powder preparation device, a feeding device and a mixing cavity. The graphene oxide powder preparation device prepares graphene oxide powder through the following steps: step A1, low-temperature pre-intercalation treatment, mixing and stirring natural graphite, concentrated sulfuric acid and oleum at low temperature to perform pre-intercalation; step A2, staged oxidation reaction, first adding an oxidizing agent to perform first-stage oxidation at low temperature, then performing second-stage oxidation at medium temperature, finally adding water and performing curing reaction at high temperature. The device solves the problems of complex preparation process of graphene-coated lithium manganese iron phosphate cathode material, and low quality of graphene oxide dispersion liquid formed by graphene oxide powder covering solvent, which affects the quality of graphene-coated lithium manganese iron phosphate cathode material.

The present application provides a kind of negative electrode for reducing the initial resistance of non-aqueous electrolyte secondary battery and achieving the improvement of durability.The negative electrode for non-aqueous electrolyte secondary battery disclosed herein has a negative electrode current collector and a negative electrode active material layer formed on the negative electrode current collector, and the negative electrode active material layer at least contains a first negative electrode active material and a second negative electrode active material.The first negative electrode active material is composed of agglomerates of flaky graphite coated with low-crystallinity carbon on at least part of the surface, and the interlayer distance of graphite of the low-crystallinity carbon based on the electron diffraction image obtained by transmission electron microscopy is 0.3375 nm.The second negative electrode active material is natural graphite or artificial graphite with an interlayer distance of graphite based on the electron diffraction image obtained by transmission electron microscopy of 0.3375 nm.Here, the mass ratio of the first negative electrode active material to the second negative electrode active material is 50:50 to 90:10.

The invention discloses a preparation method of a lithium battery negative electrode material with an optimized specific surface area of spherical graphite, and relates to the technical field of lithium ion batteries. The method comprises the following steps: treating a bimodal particle size graphite raw material, and grading and mixing natural graphite and artificial graphite to construct a core-shell structure; spray drying is combined with gas-phase chambering to form a graded porous structure; a PEDOT: PSS or PVDF-g-PEG conductive polymer solution is adopted for carrying out ultrathin coating; and carbonizing and curing the conductive network at low temperature. Through collaborative design of core-shell structure stability and graded pore channels, the tap density is maintained while the specific surface area is remarkably increased, a continuous conductive network is formed by the conductive polymer coating and a low-temperature carbonization process, and the interface charge transmission efficiency is effectively improved. The prepared negative electrode material has the characteristics of high specific surface area, excellent structural stability and low interface impedance, solves the problem that the high specific surface area is difficult to be compatible with the cycling stability in the traditional process, and is suitable for manufacturing power batteries with high energy density and long cycle life.

The invention relates to a natural graphite composite negative electrode material and a preparation method and application thereof, and the preparation method comprises the following steps: carrying out ultrasonic dispersion and drying on natural graphite and alumina sol to obtain an AS-NG precursor, carrying out auto-polymerization on the AS-NG precursor and dopamine in a Tris buffer solution to form PDA (at) AS-NG, growing a MoS2 layer on the surface of the PDA (at) AS-NG by a hydrothermal method to obtain a MoS2 / PDA (at) AS-NG precursor, and carrying out vacuum drying on the MoS2 / PDA (at) AS-NG precursor to obtain the natural graphite composite negative electrode material. And finally, performing high-temperature carbonization in an inert atmosphere to prepare the natural graphite composite negative electrode material. The material has a three-layer synergistic structure of the alumina sol filling layer, the nitrogen-doped carbon layer and the MoS2 buffer layer, and the technical problems of poor rate and short cycle life of natural graphite are successfully solved.

A negative electrode active material for a secondary battery according to an embodiment of the disclosure includes natural graphite particles having a first sphericity distribution defined by Formula 1 of 0.25 or less and a second sphericity distribution defined by Formula 2 of 0.15 or less. According to an embodiment of the disclosure, a negative electrode active material having improved electrical characteristics and life characteristics, a negative electrode including the same, and a secondary battery including the same are provided.

A natural graphite composite negative electrode material and a preparation method therefor, and a lithium-ion battery. The natural graphite composite negative electrode material comprises natural graphite, a fluffy net-shaped three-dimensional carbon network that coats the natural graphite, and an amorphous carbon coating layer arranged outside the fluffy net-shaped three-dimensional carbon network, wherein magnesium ions and / or aluminum ions are dispersed in the fluffy net-shaped three-dimensional carbon network, and the amorphous carbon coating layer is doped with copper particles and / or silver particles. The natural graphite composite negative electrode material has a three-dimensional conductive network, is doped with metals, and has a good conductivity and electrochemical cycle performance.

Disclosed are a high-performance natural graphite negative electrode material, a preparation method therefor, and a use thereof. In the negative electrode material of the present invention, a uniform and thin amorphous carbon layer coated on surfaces of each curled flake graphite layer inside the natural graphite in a core can prevent organic molecules in an electrolyte from penetrating into spherical graphite during charging and discharging to generate a new SEI film, thereby preventing delamination of the curled graphite layers inside the spherical graphite; sulfonated graphene in the inner shell has good flexibility, which can alleviate the volume expansion of natural graphite during charging and discharging, improving the cycling performance of natural graphite up to 1500 cycles. An outermost amorphous carbon layer can reduce the specific surface area of the inner sulfonated graphene, preventing reduction of first-cycle efficiency of a lithium-ion battery caused by the graphene coating. In the natural graphite negative electrode material of the present invention, the amorphous carbon layer is uniform and thin, and does not reduce the tapped density and gravimetric capacity of the anode material.

The application relates to the technical field of lithium ion battery materials, and discloses a preparation method of a high-energy-density fast-charging negative electrode material, which comprises the following steps: S1, mixing pitch, an organic solvent, a metal catalyst and an organic metal compound to obtain a coating liquid; S2, mixing oxidized natural graphite and the coating liquid, and then introducing sulfur dioxide gas to obtain a pitch / catalyst / metal oxide coated natural graphite material after reaction; and S3, carbonizing the pitch / catalyst / metal oxide coated natural graphite material in a mixed gas to obtain phosphorus-doped amorphous carbon coated natural graphite; the mixed gas in the step S3 is phosphine and argon. Through the technical scheme, the problems of low first discharge specific capacity and poor cycle performance of the graphite negative electrode material in the prior art are solved.

The present disclosure provides a negative electrode sheet and a lithium ion battery. The negative electrode sheet comprises: a current collector; and a negative active material layer formed on the current collector; wherein the negative active material layer comprises at least two negative active material layers in sequence from inside to outside, the negative active material layers comprise negative active materials selected from natural graphite or artificial graphite, and the at least two negative active material layers comprise at least one negative active material layer containing natural graphite and at least one negative active material layer containing artificial graphite. The negative electrode sheet of the present disclosure can achieve a good balance between maintaining high energy density, high fast charging capability and controlling cost due to the simultaneous use of natural graphite and artificial graphite.

This disclosure relates to a multilayer negative electrode comprising a negative electrode current collector configured to transfer electrons between an external conductor and a negative electrode active material, a first negative electrode mixture layer formed on one or both surfaces of the current collector and containing natural graphite as the negative electrode active material, and a second negative electrode mixture layer formed on the first negative electrode mixture layer and containing artificial graphite as the negative electrode active material, and a secondary lithium battery including the same.

The present invention relates to a negative electrode composition comprising a silicon-based active material and a carbon-based active material, wherein the carbon-based active material comprises at least one of a silicon-carbon composite and a silicon oxide, and the rolling density decreases in the order of natural graphite > artificial graphite > silicon-based active material when powder resistance is measured at a pressure of 800 kgf / cm2, and the electrical conductivity decreases in the order of natural graphite > artificial graphite > silicon-based active material, and the negative electrode, a lithium secondary battery, a battery module, and a battery pack comprising the same.

The invention relates to a modified graphite negative electrode material and a preparation method thereof and a lithium ion battery, the preparation method comprises the following steps: mixing natural graphite, iodized salt and a solvent, carrying out hydrothermal reaction on the obtained mixed suspension to obtain a reaction product, and carrying out solid-liquid separation and drying to obtain an intermediate material; and mixing a solution containing a precursor with the intermediate material, drying, and carbonizing the obtained mixed powder to obtain the modified graphite negative electrode material. According to the preparation method, the natural graphite is subjected to modification in two aspects of interlayer filling and surface coating, ions can be introduced by using the iodized salt, and the electrochemical performance of the graphite negative electrode material is improved by utilizing the composite action among the ions; the asphalt-based carbon material is coated on the surface of the natural graphite material, and the carbonized product forms a conductive network, so that the ionic conductivity and the electronic conductivity of the graphite negative electrode material can be improved, rapid intercalation and deintercalation of lithium ions are facilitated, and the natural graphite material shows high-rate characteristic when being applied to the negative electrode material of the lithium ion battery.

The present invention relates to an anode active material comprising: natural graphite particles; and elemental iron, elemental silicon, and elemental sulfur present on the surface, inside, or both on the surface and inside the natural graphite particles, wherein the total content of the elemental iron, the elemental silicon, and the elemental sulfur is more than 5 ppm and 100 ppm or less on the basis of the total weight of the natural graphite particles, and the content of the elemental iron is 5-50 ppm on the basis of the total weight of the natural graphite particles.

The invention belongs to the technical field of lithium ion battery positive electrode materials, and particularly relates to a preparation device and method for a graphene-coated lithium iron manganese phosphate positive electrode material, and the preparation device comprises a graphene oxide powder preparation device, a feeding device and a material mixing cavity, the graphene oxide powder preparation method of the graphene oxide powder preparation device comprises the following steps: A1, low-temperature pre-intercalation treatment: mixing and stirring natural graphite, concentrated sulfuric acid and fuming sulfuric acid at low temperature, and carrying out pre-intercalation; a2, performing staged oxidation reaction, firstly adding an oxidizing agent at low temperature to perform first-stage oxidation, then performing second-stage oxidation at medium temperature, finally adding water, and performing curing reaction at high temperature; the device solves the problems that the current preparation process of the graphene-coated lithium iron manganese phosphate positive electrode material is complicated, and the quality of the prepared graphene-coated lithium iron manganese phosphate positive electrode material is influenced due to low quality of a graphene oxide dispersion liquid formed by covering a solvent with graphene oxide powder.

A lithium secondary battery includes: a positive electrode; a separator; and a negative electrode. The positive electrode includes a positive electrode active material and a positive electrode conductive material. The negative electrode includes a negative electrode active material and a negative electrode conductive material. The positive electrode active material includes a lithium composite transition metal compound including nickel (Ni) and cobalt (Co), and the negative electrode active material includes silicon oxide, artificial graphite, and natural graphite. The positive electrode conductive material includes a particulate conductive material, a linear conductive material, and a planar conductive material, and the negative electrode conductive material includes a particulate conductive material, a linear conductive material, and a planar conductive material.

This invention relates to the field of graphite anode material technology, specifically disclosing a surface-coated natural graphite, its preparation method, and its applications. The surface-coated natural graphite comprises a negatively charged natural spherical graphite core, which is coated with a positively charged micelle solution. A negatively charged MOF is grown on the positively charged micelles through electrostatic adsorption and crystal orientation induction. After curing and drying, a hard carbon source is coated on top, and high-temperature calcination is performed to prepare a natural spherical graphite core, an onion-like carbon framework and a nanocrystalline intercalation structure, an electrostatically coupled intermediate layer, and a hard carbon shell. The graphite anode material of this invention achieves optimized ion diffusion channels, optimized conductive networks, and expanded lithium intercalation sites. This structure significantly improves cycle life and specific capacitance, making it suitable for long-life lithium batteries.

The invention relates to a method for producing graphene aerogel by using a composite bipolar plate for a waste flow battery, and belongs to the technical field of preparation of graphene aerogel. According to the present invention, the instant high temperature environment of flash Joule heat treatment is utilized to achieve the carbonization of the composite bipolar plate and the fixation of the carbon skeleton, and the thermal stress generated by the instant temperature rising is combined to convert the waste flow battery composite bipolar plate into the graphene aerogel material; through acid pickling or acid solution-water solution alternate circulating soaking treatment, metal particles which are adsorbed due to operation of the flow battery and are formed after Joule heat treatment can be effectively removed, and the high-value graphene aerogel is obtained after natural drying. The method can replace a graphene product prepared by taking natural graphite as a raw material, the production cost of the graphene aerogel is reduced, meanwhile, pollution and carbon emission caused by incineration in a traditional treatment mode of the waste composite bipolar plate are solved, and the purpose of turning waste into wealth is achieved.

The present disclosure relates to the production of active materials that may be used in a battery anode and compositions thereof. The active materials may be composed of natural graphite or graphitizable primary particles that are agglomerated into secondary particles with an agglomeration solution. The resulting secondary particles may be carbonized and graphitized prior to their use as battery active materials.