1135results about "Graphite" patented technology

The invention relates to a graphite silicon carbon composite negative electrode material, a negative electrode plate and a lithium ion battery, and belongs to the technical field of battery negative electrode materials. The graphite silicon carbon composite negative electrode material comprises a graphite inner core and a composite shell layer, the composite shell layer coats the surface of the inner core, the composite shell layer comprises a continuous carbon layer, the carbon layer is of a porous structure, and the porous structure is filled with nano silicon particles. According to the core-shell structure, through a three-stage synergistic mechanism of graphite inner core conductive supporting, porous carbon layer expansion buffering and nanometer silicon capacity contribution, the cycling stability of the negative electrode material is remarkably improved while the high specific capacity is maintained.

A negative active material, a method of preparing the negative active material, and a rechargeable lithium battery including the negative active material are disclosed. The negative active material may include a crystalline carbon core and a magnesium (Mg)-included coating layer on a surface of the core, wherein the Mg-included coating layer may include MgO and MgxSiOy (1≤x≤2 and 3≤y≤4).

The invention discloses a negative electrode material and a preparation method and application thereof. The negative electrode material comprises an inner core and a coating layer coated outside the inner core, the inner core is microcrystalline graphite with a porous structure, the coating layer is a carbonized material and comprises a cross-linking layer and a compact layer, the surface of the microcrystalline graphite is coated with the cross-linking layer, and the surface of the cross-linking layer is coated with the compact layer; wherein the cross-linking layer is formed by carbonizing heavy components in a coating agent on the surface of the microcrystalline graphite, the compact layer is formed by carbonizing weak polar groups in the coating agent, and the graphitization degree of the compact layer is greater than or equal to 94%. The negative electrode material disclosed by the invention can effectively reduce side reaction and structural breakage in the charge-discharge process, enhance the overall conductivity, and finally improve the first efficiency, the specific capacity and the cycling stability of the battery.

The invention belongs to the field of negative electrode materials, and particularly relates to a silicon-graphite composite material, a preparation method and application thereof and a lithium ion battery, the preparation method comprises the following steps: mixing and slurrying silicon powder, graphite and a composite functional additive, and then carrying out ball milling modification to obtain primary composite particles; the composite functional auxiliary agent comprises an auxiliary agent A, an auxiliary agent B and an auxiliary agent C; the primary composite particles and a carbon source liquid phase are compounded and then subjected to spray drying and heat treatment, or spray pyrolysis is directly carried out, and secondary composite particles are prepared; and carrying out modification treatment on the secondary composite particles prepared in the step 2 in a surface modification liquid, and then carrying out low-temperature annealing at 150-300 DEG C to prepare the silicon-graphite composite material. The surface modification liquid is an organic solution in which conductive lithium salt and an auxiliary agent D are dissolved. Based on the combined control of the preparation process and the structure, the silicon-based negative electrode material with ultra-long cycle life and excellent low-temperature fast charging performance can be obtained.

The invention belongs to the field of graphite materials, and particularly relates to nuclear-grade natural graphite, preparation of the nuclear-grade natural graphite and application of the nuclear-grade natural graphite to preparation of high-temperature gas cooled reactor fuel spherulis.The preparation method comprises the steps that a natural graphite raw material is subjected to first-stage heat preservation treatment at the temperature T1 in advance, and a first-stage material is obtained; grinding and grading the first-section material to obtain graphite powder A and graphite powder B; then shaping and grading the graphite powder A to obtain graphite powder C; mixing the graphite powder B and the graphite powder C to obtain graphite powder D; the graphite powder D is subjected to liquid phase treatment in acid liquor in advance, and graphite powder E is obtained; the graphite powder E is subjected to two-stage gas-solid treatment with gas control and pressure control, and the nuclear-grade natural graphite is prepared. According to the method, the purity of the graphite can be obviously optimized, and in addition, the loss of strength in the purification process can be avoided, so that the graphite which is more than 5N, ultralow in nuclear reaction degradation impurities, excellent in strength and capable of meeting the application requirements of a nuclear reaction device can be obtained.

One or more aspects of the present disclosure provide methods for recovering and upgrading a secondary battery anode material. The method includes: producing a raw anode material by processing a spent battery material containing a first anode material; purifying the original negative electrode material; and generating a second anode material using the purified raw anode material. In some embodiments, the first anode material includes graphite. And the second negative electrode material comprises a graphite-silicon composite material and / or a graphite-silicon oxide composite material. The second negative electrode material may be a battery-grade negative electrode material that can be directly used for a new battery electrode.

The invention discloses a waste graphite regeneration method, a regenerated graphite negative electrode material and a secondary battery, and the waste graphite regeneration method comprises the following steps: roasting: carrying out oxidizing roasting on waste graphite slag to obtain roasted graphite; shaping: shaping and grading the roasted graphite to obtain shaped graphite; graphitization: graphitizing the shaped graphite to obtain coarse graphite; and impurity removal: performing impurity removal on the coarse graphite to obtain impurity-removed graphite. According to the method for regenerating the waste graphite, waste is turned into wealth, and the problems of environmental pollution and resource waste when the waste graphite slag is treated as solid waste are solved; the used equipment is industrial equipment mature in the market, the technology is mature, safety and reliability are achieved, the investment cost is low, and the large-scale production requirement can be met. Importantly, the high-quality battery-grade graphite negative electrode material with high purity, high capacity, long circulation and good fast charging performance can be obtained, and finally the cyclic utilization of turning waste into wealth is realized.

The invention discloses a carbon-coated surface modification method of granulated graphite powder, and belongs to the technical field of lithium ion battery negative electrode materials. The method comprises the following steps: mixing crystalline flake graphite and a hard carbon binder, granulating to obtain particles with d50 of 15-25 microns, adding a soft carbon coating agent, carbonizing, and screening to finally obtain the granulated graphite material. According to the method, two key links of granulation and carbon coating are comprehensively considered, the synergistic effect of a hard carbon binder and a soft carbon coating agent and the influence of different carbonization treatment modes such as gradient carbonization and co-carbonization on the performance of the granulated graphite powder are systematically studied, various parameters in the granulation and carbon coating processes are accurately regulated and controlled, and the performance of the granulated graphite powder is improved. Comprehensive optimization of granularity, structural stability, electrochemical performance and the like of the granulated graphite powder is realized, a brand new technical thought and method are expected to be provided for research, development and production of a lithium ion battery negative electrode material, and further development of a lithium ion battery technology is promoted; and the method has extremely important strategic significance and wide application prospect for promoting the progress of the new energy industry and optimizing the energy structure.

The invention discloses a preparation method of high-rate fast-charging graphite from a semi-calcined coke raw material, and belongs to the technical field of batteries, and the preparation method comprises the following steps: S1, crushing and shaping the semi-calcined coke raw material; s2, carrying out graphitization high-temperature treatment on the crushed and shaped semi-calcined coke; s3, mixing and coating the semi-calcined coke subjected to graphitization high-temperature treatment with a coating agent; s4, performing high-temperature carbonization heat treatment on the semi-calcined coke mixed and coated with the coating agent; s5, screening the petroleum coke semi-calcined coke subjected to high-temperature carbonization heat treatment to obtain a semi-calcined coke raw material high-rate fast-charging graphite; the material has the advantages of large discharge capacity, good cycle performance, good electrochemical performance, high discharge plateau and plateau retention rate, good large-current charge-discharge performance, good safety, good adaptability to electrolyte and other additives, stable product properties, almost no difference between batches, simple and feasible preparation method, and suitableness for industrial production.

The invention discloses a preparation method of a high-rate wide-temperature-range regenerated graphite negative electrode material, and belongs to the technical field of lithium ion battery recovery. The invention provides a preparation method of a high-magnification wide-temperature-range regenerated graphite negative electrode material, which combines a multi-section high-temperature synergistic treatment means and a lithium-rich catalytic surface modification technology, realizes impurity removal of a waste graphite negative electrode under the condition of lower energy consumption, and realizes effective repair of a graphite crystal structure. According to the method, through the synergistic effect of ultrahigh-temperature gasification and the reactive atmosphere, trace metal impurities which are most difficult to remove and fluorine-containing compounds with thermal stability are almost thoroughly removed, and the purity of the regenerated graphite is improved to be close to the level of a primary material (the purity gt is 99.9%); and a lithium-rich catalytic surface modification technology is adopted, so that the graphite surface can be stabilized, and the rate capability and low-temperature performance of the material are improved. The graphitization degree (gt; 95%) of the material is remarkably improved through the in-situ defect repairing effect driven by ultrahigh temperature, and the highly-ordered layered crystal structure and the excellent conductive network of the material are recovered.

A negative electrode material, comprising composite particles. Each of the composite particles comprises a core and an amorphous carbon coating layer located on the surface of the core, wherein the core comprises a graphite framework and amorphous carbon in the graphite framework; and the amorphous carbon coating layer has a thickness of 10-50 nm. Raman spectral area scanning is performed on the negative electrode material, and there are 400 Raman spectral area scanning points; and the average ID / IG value of the Raman spectrum of the negative electrode material is 0.10-0.20, wherein the proportion of the number of scanning points having a single-point ID / IG value of less than 0.2 is greater than 60%. The negative electrode material has a high compaction density, a high capacity, a low expansion rate, good rate performance, and good high-temperature cycling performance.

The present invention provides a method for preparing battery-grade graphite from waste lithium-ion batteries comprising steps of: (i) implementing heat treatment on scrap mixture comprising cathode and anode materials of waste lithium-ion batteries and their components thereof; (ii) adding an acid solution containing redox agent into the mixture to obtain leaching liquid and leaching slag and washing the leaching slag with water; (iii) adding a solvent to the washed leaching slag comprising at one selected from hydrocarbon, alcohol, ketone, ether and water and mixing by stirring, milling or sonication and further adding a carbon source material that is completely dispersed in the slurry, and removing the solvent from the slurry to obtain mixed graphite; (iv) putting the mixed graphite into a furnace for oxygen-free heating and carbonization to obtain coated graphite; and (v) putting the coated graphite into a high temperature graphitization furnace for oxygen-free heating and graphitization to obtain recycled graphite.

The invention provides a surface modified carbon negative electrode material, a preparation method thereof and a battery. The preparation method comprises the following steps: mixing a graphite carbon source and a pore-forming agent, and graphitizing the obtained mixture to form porous graphite; performing oxidation treatment on the porous graphite to prepare porous graphite oxide particles; the porous graphite oxide particles are placed in a tin source solution containing tin cations, the tin source solution is attached to the surfaces of holes of the porous graphite oxide particles, and tin oxide attached to the surfaces of the holes of the porous graphite oxide particles is formed based on the tin source solution; and the porous graphite oxide particles are placed in a carbon-containing reducing gas environment to be subjected to calcination treatment, and the carbon-coated tin nanowires are prepared on the basis of the tin oxide. According to the preparation method, the surface and holes of the carbon negative electrode material are modified by adopting the carbon-coated tin nanowires, so that the discharge performance of the battery at relatively high rate can be effectively improved.

The invention discloses a lithium ion battery artificial graphite negative electrode material, a preparation method thereof and a lithium ion solid-state battery, and belongs to the technical field of lithium ion solid-state batteries. Carrying out flash evaporation Joule heating on the pretreated carbon source material in an inert atmosphere, then rapidly cooling to obtain a graphitized intermediate, and screening, washing and drying the graphitized intermediate; mixing and reacting the graphitized intermediate with strong acid under an ice bath condition, and oxidizing and expanding the graphitized intermediate to obtain expanded graphite; and mixing the expanded graphite with mercaptan acetic acid and ethyl acetate, adding a catalyst, and reacting for a certain time to obtain the artificial graphite negative electrode material of the lithium ion battery. According to the invention, by introducing a flash Joule pulse graphitization technology, sulfur-oxygen dual-function synergistic modification and structure-performance integrated design, three technical bottlenecks of a traditional artificial graphite negative electrode material are systematically solved: the rate capability is limited, the interface stability is poor and the volume expansion is obvious.

The invention discloses a production method of a special graphite material bipolar plate, a production raw material formula comprises a graphite raw material and an impregnant, and the component of the impregnant comprises epoxy resin. The method mainly comprises the following steps: S1, continuously pressing a graphite raw material into a low-density flexible graphite plate through a rolling process; s2, placing a low-density flexible graphite plate in an impregnation container, injecting the impregnant, and enabling the impregnant to fully permeate under a vacuum condition; s3, the impregnated graphite plate is placed in a pressing mold, and a monopolar plate with a runner structure is formed through pressing; cleaning the surface of the monopolar plate by using a cleaning agent; and S4, the prefabricated monopolar plate is heated and cured. The preparation method has the advantages that the prepared special graphite material bipolar plate has the advantages of excellent conductivity, chemical stability, toughness, continuous productivity, light weight and the like, the thinnest thickness can reach 0.8 mm, and the requirement of a high-end passenger car battery on the performance of the graphite material bipolar plate can be completely met.

Provided in the present disclosure are a negative electrode sheet, a secondary battery, an electric device, and a negative electrode active material and a preparation method therefor. The negative electrode sheet comprises a negative electrode current collector and a negative electrode film layer located on at least one surface of the negative electrode current collector, wherein the negative electrode film layer comprises a negative electrode active material. The negative electrode active material comprises first artificial graphite and second artificial graphite, wherein the first artificial graphite comprises primary particles, and the second artificial graphite comprises secondary particles. The powder OI value of the negative electrode active material is 2.5-6.5; and the powder compaction density of the negative electrode active material under a pressure of 50,000 N is 1.75-1.94 g / cc.

The preparation method comprises the following steps: S1, adding silicon powder, graphite, a carbon source and a pore-forming agent into a solvent to obtain slurry; the pore-forming agent comprises ammonium citrate and polylactic acid; s2, performing spray drying on the slurry to obtain precursor microspheres; s3, the precursor microspheres are subjected to first-stage low-temperature oxidation to form macropores, second-stage medium-temperature melting to form mesopores, third-stage high-temperature carbonization and cooling shaping, the heat preservation temperature of the first-stage low-temperature oxidation is 180-200 DEG C, the heat preservation temperature of the second-stage medium-temperature melting is 340-360 DEG C, the heat preservation temperature of the third-stage high-temperature carbonization is 800-900 DEG C, and the gradient pyrolysis dual-pore-forming silicon-carbon negative electrode material is obtained. Through combined use of ammonium citrate and polylactic acid and control of gradient pyrolysis conditions, synergistic distribution of double-peak gradient pores is formed, and effective improvement of the first effect and the cycle performance can be realized.

The invention relates to the field of negative electrode materials, in particular to a carbon nanotube enhanced negative electrode material and a preparation method thereof. The carbon nanotube enhanced negative electrode material comprises the following substances in parts by weight: an artificial graphite inner core, a carbon nanotube coating layer and an asphalt coating layer which are sequentially coated from inside to outside, and the carbon nanotube coating layer further comprises magnetic modified particles, the asphalt coating layer comprises the following substances in parts by weight: 25-35 parts of biochar particles; 65 to 70 parts of asphalt particles; and 0.1-0.5 part of a dispersant. According to the application, a continuous conductive network can be constructed through the carbon nanotube coating layer, the electron transmission efficiency is improved, and meanwhile, the asphalt coating layer is compounded through the biochar particles and the asphalt. The synergistic effect of the three-layer structure can repair the surface defects of the artificial graphite, reduce the side reaction of the electrolyte and inhibit the volume expansion in the charge-discharge process, so that the cycling stability and conductivity of the negative electrode material are comprehensively improved.

A process for producing solar grade silicon from silica sand employs a plurality of plasma furnaces to perform a sequence of chemical reactions together with other process steps to produce solar grade silicon. The plasma furnace generates a stable dirty-air, donut-shaped plasma into which particulate matter can be introduced. The plasma in the first two stages is formed by gases from the chemical reactions and in the third from inert gasses. Cyclone separators are used to extract particulates from the plasma in an inert gas that prevents reverse reactions as the particulate cools.

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 invention provides a hydrophilic modified porous graphite-based phase change heat storage material and a preparation method thereof, and relates to the technical field of phase change heat storage materials. The hydrophilic oxide layer is constructed on the pore surface of the porous graphite, so that the porous graphite is changed from hydrophobicity to hydrophilicity, and the application limitation caused by original strong hydrophobicity is effectively overcome. The oxide layer is stable in property in a high-temperature environment, the applicable temperature range of the material is remarkably widened, erosion of oxygen to a carbon skeleton can be blocked, the structural integrity of the porous graphite is protected, and the service life of the material is prolonged. The high-enthalpy polar phase change material can be efficiently compounded with the hydrophilic modified porous graphite in a solution spontaneous impregnation manner by virtue of good flowability and permeability of an aqueous solution of the high-enthalpy polar phase change material, so that the preparation process is greatly simplified. The finally prepared hydrophilic modified porous graphite-based phase change heat storage material has high thermal conductivity and high heat storage density, shows excellent comprehensive performance, and solves the problem that a polar phase change substance with a high enthalpy value is difficult to be effectively compounded with porous graphite.

The invention relates to the technical field of graphite materials, in particular to a carbon-coated graphite negative electrode material with gradient pores and a preparation method of the carbon-coated graphite negative electrode material. The method comprises the following steps: performing crystal high-temperature carbonization on the surface of graphite powder by adopting a carbon skeleton precursor to form a carbon skeleton layer, constructing a dipping carbon source solution in the carbon skeleton layer in a step-by-step dipping manner to form gradient distribution, and performing high-temperature carbonization at 1000-1400 DEG C to obtain the carbon-coated graphite material with gradient pores. The design of the gradient pore structure optimizes the ion transmission path, reduces the interfacial effect, and avoids lithium dendrites formed by Li < + > which cannot be diffused and gathered on the surface of the graphite negative electrode in time during large-current charging of a traditional structure, so that the rate capability of the graphite negative electrode is improved; the coating layer is effectively prevented from falling off from graphite in the charging and discharging process, and the stability of the electrode can be further improved.

The invention relates to a multi-conductive-agent composite conductive paste for a lithium battery and a preparation method of the multi-conductive-agent composite conductive paste, and belongs to the technical field of lithium battery conductive pastes.The multi-conductive-agent composite conductive paste is characterized in that an iron-molybdenum catalyst is loaded on expanded graphite, then vertical orientation carbon nanotubes and transverse graphene blades are grown in situ, the specific surface area is increased, and the expanded graphite serves as a layered carrier; a metal alloy catalyst can be uniformly loaded in natural pores of the carbon nanotube, a layered framework is kept from collapsing at a high temperature, support is provided for directional growth of a carbon material, electrons can be rapidly transmitted along the carbon nanotube when the composite conductive paste is prepared, gaps of the carbon nanotube are filled by graphene blades, a breakpoint-free conductive network is formed, and the composite conductive paste is prepared. And meanwhile, abundant pores provide channels for lithium ion diffusion, so that the conductive efficiency is improved from the source of the structure, and abundant specific surface area and subsequent nitrogen and sulfur loading provide sufficient sites.

The present application provides a carbon material, a method for preparing the same, and a secondary battery and an electrical device comprising the same. The carbon material includes a pore structure, wherein the carbon material has 3R and 2H phases and satisfies 0<I3R(101) / I2H(004)≤0.100, in which I3R(101) is the diffraction peak intensity of 101 crystallographic plane of the 3R phase in the X-ray diffraction pattern of the carbon material, and I2H(004) is the diffraction peak intensity of 004 crystallographic plane of the 2H phase in the X-ray diffraction pattern of the carbon material. The carbon material provided in the present application can make the secondary battery have high initial columbic efficiency and also good cycling and dynamic performances.

The invention discloses superfine aquadag for drawing a high-strength tungsten filament and a preparation method of the superfine aquadag, and belongs to the technical field of metal processing and forming. According to the preparation method, the ultrafine graphite dispersion liquid with small particle size and proper particle size distribution is obtained by improving the surface treatment and grinding process of the graphite powder; and uniformly mixing the thickening agent, the binder and the graphite dispersion liquid by adopting a segmented stirring method to obtain the finished product aquadag which is stable in component and not easy to layer. The aquadag provided by the invention has the characteristics of small particle size and large particle size distribution range, the ash content is low, the specific gravity is large, the cost is low, and meanwhile, the lubricity and the adhesion performance in the drawing process are remarkably improved. The aquadag provided by the invention can be used for processing superfine tungsten wires with the wire diameter of less than 30 microns and high tensile strength, and can meet the processing requirements of the novel photovoltaic diamond wire industry.

The present invention belongs to the technical field of composite silicon-based negative electrode materials and discloses a composite silicon-based negative electrode material, a preparation method, and a solid-state battery. The composite silicon-based negative electrode material comprises a graphite substrate and silicon carbide nanowires and nanosilicon particles attached to the surface of the graphite substrate. The silicon carbide nanowires are interwoven to form a network structure, and the nanosilicon particles are dispersed in the network structure. The nanosilicon particles are dispersed in the network of interwoven silicon carbide nanowires, presenting a porous structure similar to that of reinforced concrete. The porous structure provides space for volume expansion, mitigating damage to the electrode structure caused by volume expansion during lithium insertion and extraction of the silicon-based negative electrode. At the same time, the one-dimensional silicon carbide therein, due to its high mechanical strength, can mitigate damage to the electrode structure caused by long-term cycling of the silicon negative electrode, thereby improving the mechanical properties of the silicon negative electrode and thus improving the cycling performance of the silicon electrode.

The invention relates to a novel silicon-carbon material and a preparation method and application thereof, the silicon-carbon material comprises a graphite substrate, a silicon layer coating the outer surface of the graphite substrate and a silicon carbide layer coating the outer surface of the silicon layer, and a graphite-silicon-silicon carbide three-layer composite structure is formed; wherein the silicon layer and the silicon carbide layer are formed by one-time continuous deposition through a chemical vapor deposition process; the silicon carbon material is applied to a negative electrode material of a lithium ion battery. According to the novel silicon-carbon material as well as the preparation method and the application thereof, a single chemical vapor deposition process is adopted, and selective deposition of a silicon material and a silicon carbide material is realized by accurately regulating and controlling the hydrogen content in a deposition atmosphere on the premise of not changing equipment and raw materials; according to the method, the novel silicon carbon material with the SiC coated silicon structure (SiC coated Si / G) is successfully prepared.

The invention discloses a preparation method of graphite for a large semiconductor, and belongs to the technical field of graphite for semiconductors. The method comprises the steps of raw material pretreatment, forming process, graphitization, purification and post-treatment, wherein needle coke and a carbon-based functional material are mixed, and a carbon-based dispersing agent is added under the action of a gradient magnetic field for dispersion to obtain a pretreated raw material; filling the mixture into a carbon-based mold, carrying out cold isostatic pressing molding through cooperation of gradient pressure and a gradient magnetic field, and absorbing stress through a carbon-based buffer material to obtain a molded green body; placing the green body in a large graphitization furnace, regulating and controlling a magnetic field in sections, introducing mixed gas, strengthening the reaction through a carbon-based catalytic material, and prolonging the reaction time of a core part by utilizing gas backflow to complete graphitization and purification; and finally, carrying out plasma surface activation, boron nitride coating deposition and annealing treatment to obtain a graphite product for a large semiconductor. The problems that the purity of a large green body is out of control, the impurity removal gradient difference is large and the stress is large can be effectively solved, and the product performance is excellent.

The invention relates to the technical field of lithium / sodium ion batteries, in particular to a preparation method of a highly graphitized coated carbon material based on phenolic resin, which comprises the following steps: uniformly mixing formaldehyde, resorcinol and a basic catalyst, and then catalyzing and curing; carrying out carbonization treatment on the uncarbonized phenolic resin based on a gradient heating method; mixing ethidene diamine, dichloromethane and carbonized phenolic resin, and heating in an oil bath; and placing the cured and coated graphitized phenolic resin in a tubular furnace for highly graphitizing. According to the preparation method of the highly-graphitized coated carbon material based on the phenolic resin, high ordering of a carbon layer is achieved through gradient heating graphitization, a carbon six-membered ring plane is promoted to expand, an ABAB stacked graphite structure is formed, the conductivity is effectively improved, a CVD coating and nitrogen doping synergistic technology is combined, a CVD reaction is formed through ethanediamine and dichloromethane, and the high-graphitization coated carbon material based on the phenolic resin is obtained. Functional groups such as pyridine-N and graphite-N are introduced to the surface of the carbon layer, so that the interface bonding force between the carbon layer and the matrix is enhanced, and the conductivity of the carbon layer is further improved.

The present embodiments relate to a negative electrode active material, a method for manufacturing the same, a negative electrode comprising the same, and a lithium secondary battery comprising the same. The negative electrode active material includes a core portion comprising at least one coarse graphite particle having an average particle diameter (D50) ranging from 5 to 20 µm and at least one fine graphite particle having an average particle diameter (D50) of less than 5 µm, wherein the fine graphite particles account for from 5 wt% to 30 wt% based on the total weight of the coarse graphite particles and the fine graphite particles.