3051 results about "Carbon layer" patented technology

The invention discloses a silicon-carbon negative electrode material, porous carbon and a preparation method, the porous carbon is prepared by mixing ammonium fluoride and a pre-carbonized material to prepare a premix; and putting the premix in an inert atmosphere, and carrying out pre-activation, drying, carbonization, activation and crushing treatment to obtain the composite material. And uniformly depositing the nano silicon particles into the porous carbon skeleton through a mature CVD (Chemical Vapor Deposition) process to obtain the silicon-carbon composite material. Fluorine and nitrogen co-doping modification can increase the defect degree of a carbon skeleton, efficiently relieve mechanical stress accompanied by lithium storage volume expansion of the silicon negative electrode in a micro scale, provide abundant lithium ion transport and mass transfer channels and enhance the conductivity of porous carbon, and ammonium fluoride is used as a supplementary activator besides water vapor, so that the porosity of the porous carbon is further improved, and the conductivity of the porous carbon is improved. An effective space is provided for uniform deposition of silicon, the fluorine-containing carbon layer can induce formation of a high-stability SEI film rich in LiF on the surface of the nano silicon material, and the interface stability and coulombic efficiency of the silicon negative electrode are further improved.

The invention provides a lithium iron manganese phosphate positive electrode material and a preparation method and application thereof, the lithium iron manganese phosphate positive electrode material comprises a doped type iron manganese phosphate inner core and a coating layer coating the surface of the doped type iron manganese phosphate inner core, and the coating layer is a lithium-containing carbon layer; the doped iron manganese phosphate inner core comprises doped ions, and in the particles of the doped iron manganese phosphate inner core from inside to outside, the content gradient of manganese ions and iron ions is reduced, and the content gradient of the doped ions is increased. According to the lithium manganese iron phosphate positive electrode material with the structure, a series of problems caused by poor phase structure stability, poor conductivity and Jahn-Teller effect and manganese dissolution of the material in the lithium manganese iron phosphate positive electrode material can be effectively improved; further, the conductivity of the lithium manganese iron phosphate positive electrode material and the comprehensive performance of gram volume, cycling stability and the like when the lithium manganese iron phosphate positive electrode material is applied to a battery are improved.

The invention relates to the technical field of PVC pipe production and processing, and particularly discloses a PVC pipe composition and a preparation method of a PVC pipe. PVC resin and PE resin are compounded, the problem of PVC decomposition caused by high temperature in the processing process is reduced, meanwhile, the PE resin has good flexibility, and by compounding the PVC resin and the PE resin, the PVC resin and the PE resin have good flexibility, so that the PVC pipe composition is more stable in performance. The mechanical property of the PVC pipe can be improved; 4-carboxyphenylboronic acid in the composite modified attapulgite provided by the invention forms a B-O-B cross-linked network structure at a high temperature, the 4-carboxyphenylboronic acid can have a synergistic effect with composite metal oxides (zinc oxide and manganese oxide), the thermal stability and compactness of a carbon layer are improved, and the flame retardant property of the PVC pipe is further improved; a flexible alkyl long-chain structure is formed through copolymerization of 1, 4-diol, reversible deformation occurs under the action of external force, and the mechanical property of the PVC pipe is further improved.

The invention discloses a silicon-carbon composite material and a preparation method thereof, a pole piece and a battery. The silicon-carbon composite material comprises a cluster structure and a third carbon layer coating the cluster structure, wherein the cluster structure comprises a plurality of silicon-carbon composite particles, pores are distributed among the plurality of silicon-carbon composite particles, each silicon-carbon composite particle has a core-shell structure, each silicon-carbon composite particle comprises an inner core and an outer shell coating the inner core, each outer shell sequentially comprises a first carbon layer and a second carbon layer in the direction far away from the inner core, the first carbon layer comprises a conductive carbon material with a three-dimensional structure, an annular gap exists between the second carbon layer and the first carbon layer, and the inner core comprises porous silicon nanoparticles. The battery prepared from the silicon-carbon composite material has excellent electrochemical performance.

The invention discloses a uniform carbon-coated lithium iron phosphate positive electrode material and a preparation method thereof, and relates to the technical field of lithium iron phosphate positive electrode materials, the uniform carbon-coated lithium iron phosphate positive electrode material comprises lithium iron phosphate matrix particles, the lithium iron phosphate matrix particles are coated with a composite carbon layer, and the composite carbon layer is doped with cerium modified tantalum carbide nanocrystals; the preparation method of the cerium modified tantalum carbide nanocrystal comprises the following steps: dissolving pentaethoxy tantalum and cerous nitrate in ethylene glycol, adding urea as a precipitator, and synthesizing a Ta-Ce-O precursor through a microwave-assisted solvothermal method; the Ta-Ce-O precursor and phenolic resin are mixed and then subjected to ball milling and sintering, and the cerium modified tantalum carbide nanocrystal is obtained. By introducing a small amount of cerium modified tantalum carbide nanocrystals into the composite carbon layer for many times, uniform coating of the composite carbon layer can be realized, and the electrochemical performance of the lithium iron phosphate positive electrode material is enhanced.

The invention discloses a silicon-carbon composite material which comprises porous carbon, silicon-containing particles are distributed on the surface of the porous carbon and in pore channels, the surfaces of the silicon-containing particles are coated with aluminum silicate layers, and the surface of the porous carbon is coated with a carbon layer. The invention also discloses a preparation method of the silicon-carbon composite material, which comprises the following steps: sequentially carrying out vapor deposition on the porous carbon by using silane, aluminum steam and vapor carbon to obtain the silicon-carbon composite material. The invention also discloses an application of the silicon-carbon composite material in a negative electrode material. When the silicon-carbon composite material is used in the lithium ion battery, the initial coulombic efficiency and the capacity retention rate of the lithium ion battery can be improved, and the expansion rate of a pole piece is reduced.

The invention discloses a LiAlO2 fast ion conductor coated silicon-carbon composite material as well as a preparation method and application thereof, and belongs to the technical field of lithium ion battery materials. The LiAlO2 fast ion conductor coated silicon carbon composite material has a core-shell structure; an inner core of the composite material is a silicon-carbon composite material, the silicon-carbon composite material is formed by coating a three-dimensional carbon material with an amorphous carbon layer and loading a nano silicon compound, a shell of the composite material is a LiAlO2 fast ion conductor layer, and the silicon-carbon composite material with a three-dimensional network structure is constructed, and the surface of the silicon-carbon composite material is coated with the LiAlO2 fast ion conductor layer, so that the composite material is obtained. According to the present invention, with the LiAlO2, the volume expansion of the nanometer silicon during the charge-discharge process can be effectively relieved, the stability of the silicon-carbon composite material structure can be improved so as to significantly improve the cycle performance of the battery, and the LiAlO2 can provide the rapid channel for the transmission of the lithium ion during the charge-discharge process so as to improve the rate performance of the battery;

The invention belongs to the field of electrochemistry, and discloses a silicon-carbon negative electrode material based on nanocellulose and a preparation method and application thereof. The preparation method comprises the following steps: dispersing cellulose in deionized water, and carrying out physical stripping and ionic liquid assisted acidolysis to obtain a cellulose colloidal solution; and dispersing the conductive agent and the carbon source into the colloidal solution, adding the coupling agent and the silicon source, and carrying out spray drying and sintering. According to the invention, nano cellulose preparation and silicon carbon preparation processes are combined, so that an intermediate separation process is reduced, and the process is simplified. Meanwhile, in the silicon-carbon balling process, the ionic liquid and the coupling agent in the slurry can induce and promote surface combination of the carbon source and the silicon source; the nano cellulose promotes nano-micro forming of components such as silicon and carbon, and is coupled with the conductive agent in the carbonization process to form an internal conductive network and a coating layer; in the carbonization process, hydrolysis catalyst metal ions play a role in catalyzing gas source cracking deposition to form a stable coating carbon layer. The silicon-carbon material is novel in route, rapid electron transmission and capacity exertion are guaranteed through the conducting layers from inside to outside, and the cycling stability of the material can be improved through the multi-carbon-layer coating structure.

The invention provides a long glass fiber reinforced flame-retardant ceramic polypropylene material and a preparation method thereof. Comprising the following components in parts by weight: 0-20 parts of polypropylene, 30-60 parts of flame-retardant long glass fiber master batch and 40-70 parts of ceramic master batch. According to the invention, the multi-gradient melting point glass powder, the phosphorus flame retardant, the tetrapod-like zinc oxide whisker, the long glass fiber and the ceramic forming filler are matched, so that a carbon layer can be kept compact in structure and high in structural strength during combustion, resists flame pressure and is not damaged; an interlayer structure blocks a heat conduction path, the back surface temperature is obviously reduced, and the material is prevented from softening and collapsing. The obvious effects of ablation resistance, good processing, high strength, good flame retardance, low cost and light weight are achieved.

The invention discloses an antistatic PPO material based on graphene and a preparation method thereof.The preparation method comprises the steps that aminated polyphenyl ether and modified filler react to prepare modified polyphenyl ether, the modified polyphenyl ether is treated with benzenesulfonyl chloride to prepare the antistatic PPO material, when the aminated polyphenyl ether and the modified filler are used, the modified filler is equivalent to a cross-linking agent, and when the modified filler is used for modifying the aminated polyphenyl ether, the modified filler is equivalent to a cross-linking agent; the modified filler is interspersed among the molecular chain segments, graphene is arranged in the modified filler and has a very good conductive effect, so that the material has an antistatic effect, and the surface of the modified filler contains an organic silicon chain segment, so that the antistatic property of the material is improved; when the material is combusted, a phosphorus-containing organic silicon chain segment on the surface of the modified filler can form a P-O-Si compact carbon layer, a nitrogen element on a side chain can generate amino free radicals, then active hydrogen atoms and hydroxyl free radicals are captured, a combustion chain reaction is interrupted, a sulfur element can release sulfur dioxide gas, the oxygen concentration is further diluted, and the oxygen concentration is reduced. Therefore, the material has a good flame-retardant effect.

The invention belongs to the technical field of fuel cells, and particularly relates to carbon paper for a gas diffusion layer with a water-gas management function and a preparation method of the carbon paper. The carbon paper for the gas diffusion layer comprises at least three alternately stacked carbon layer structures, odd layers are macroporous carbon layers, and the macroporous carbon layers are formed by dipping carbon fiber base paper in a mixed solution of resin and a conductive material and drying the carbon fiber base paper; the even-numbered layers are small-hole carbon layers, and the small-hole carbon layers comprise resin and conductive materials and are coated on the surfaces of the odd-numbered layers; the odd-numbered layers and the even-numbered layers are compounded through a hot-pressing process to form a composite material; the composite material is subjected to high-temperature heat treatment to form a carbon paper A conductive network is formed in the carbon paper, the carbon paper with higher conductivity is prepared, part of the conductive material is filled in the carbon paper to build a microporous structure, the low-gram-weight base paper forms a macroporous structure, and the conductive material and the resin are mixed to form a microporous structure, so that the water and gas management capability is favorably improved.

The application relates to the technical field of material preparation, and discloses multi-element carbon-coated lithium manganate, a preparation method thereof and a secondary battery. The multi-element carbon-coated lithium manganate comprises a lithium manganate core and a carbon nanotube layer and a hard carbon layer which are sequentially coated on the lithium manganate core. The chemical formula of the lithium manganate core is LiAl a X b Mn 2‑a‑b O4, wherein 0.01<=a<=0.10, 0.01<=b<=0.05, and X comprises at least one of Co, Cr, Ti, V and B. The preparation method of the multi-element carbon-coated lithium manganate comprises the following steps: (I) preparing doped lithium manganate, (II) preparing carbon nanotubes and (III) multi-element carbon coating. The multi-element carbon-coated lithium manganate has high conductivity, rate performance, cycle performance and safety performance, and can be used as an alternative positive electrode material with high cycle and excellent fast-charging performance.

The invention relates to the technical field of energy storage, in particular to a secondary battery and a preparation method thereof, a battery pack, an energy storage system and electric equipment. The secondary battery comprises a positive electrode active particle, the positive electrode active particle comprises an inner core and a carbon layer coating the inner core, and the inner core comprises one or more of lithium transition metal phosphate and lithium transition metal oxide; part of the positive electrode active particles are cracked, the width of the cracked crack is 10 nm to 30 nm, and the length of the cracked crack is 300 nm to 800 nm. The secondary battery provided by the invention has good cycle performance while the discharge gram capacity is improved, and is beneficial to wide application in the field of energy storage.

The invention provides a sphere-like silicon-carbon negative electrode material and a preparation method and application thereof, and particularly relates to the technical field of negative electrode materials, the negative electrode material comprises a sphere-like porous carbon skeleton, silicon nanoparticles distributed in the sphere-like porous carbon skeleton, and an amorphous carbon layer coating the surface of the sphere-like porous carbon skeleton, the particle appearance of the sphere-like porous carbon skeleton is of a round irregular or asymmetric polyhedral structure and comprises one or more of a potato shape, an ellipse shape, an olive shape, a long strip shape and a pomegranate shape, the particle of the sphere-like porous carbon skeleton is provided with a plurality of asymmetric faces, fillets are formed between the faces, and the radius of the fillets does not exceed 20 microns. The problem of structural damage of the material under the action of external force such as rolling can be effectively relieved, good mechanical stability is kept, excellent bonding performance can be achieved in the electrode coating process, the ion transmission path of the material is improved, and the electronic conductivity and the lithium ion diffusion performance are improved.

The invention belongs to the technical field of sodium-ion batteries, and particularly relates to a preparation method of a coal-based hard carbon material and application of the coal-based hard carbon material in a sodium-ion battery negative electrode. The preparation method of the hard carbon material comprises the following steps: carrying out acid-base chemical heat treatment on a coal-based material to obtain an ash-removed and dried precursor material, and activating the material by water vapor to obtain a target sample with etched micropore inner gaps, and in the subsequent carbonization process, the carbon layer is twisted to form a closed pore structure to obtain the electrode material. According to the invention, the application of the rich-resource coal precursor and the high carbon conversion rate in the sodium ion battery is realized, and the storage capacity of sodium and the cycling stability of the material are effectively improved. The coal-based hard carbon material can be used for preparing a sodium ion battery and has important application value.

The invention relates to the field of high polymer materials, in particular to a burnthrough-resistant PC composite material and a preparation method thereof. According to the burnthrough-resistant PC composite material provided by the invention, the bromine flame retardant, the silicon flame retardant and the boron flame retardant are used as one of the components, during combustion, bromine is used for absorbing free radicals, so that the oxidation reaction is slow, heat is reduced, silicon and boron are crosslinked to form a B-Si vitrification protection layer, heat insulation and oxygen insulation are realized, the compactness of a carbon layer is complemented, a sinking carbon layer is formed, and matrix resin is prevented from being combusted; the melt strength of the PC composite material is synergistically improved, burnthrough is prevented, and the PC composite material has excellent burnthrough resistance and meets the requirements of new national standards. The invention further provides a preparation method of the burnthrough-resistant PC composite material, the method is simple in process and high in product benefit, and the technical problem of how to improve the burnthrough resistance of the PC composite material is efficiently solved.

The invention discloses a method for preparing a platinum-based alloy catalyst by using a plasma enhanced chemical vapor deposition low-temperature technology, relates to a preparation method of a platinum-based alloy catalyst, and aims to solve the technical problems that a carbon layer is not uniformly coated and metal particles of the catalyst are easy to agglomerate in a high-temperature calcination process in the existing platinum-based alloy catalyst prepared by carbon coating. The method comprises the following steps: 1, preparing Pt / C by a polyhydric alcohol reduction method; 2, pre-treating a Pt / C catalyst; 3, preparing M-Pt / C by a dipping evaporation method; 4, PECVD carbon shell coating is carried out; (5) alloying; and 6, removing a part of carbon shell to obtain the platinum-based alloy catalyst. When the Pt / C catalyst is used for preparing a membrane electrode of a proton exchange membrane fuel cell, the peak power density can reach 1.72-1.89 W / cm < 2 > under a hydrogen-air condition, which is improved by 20.3% and 32.2% compared with a membrane electrode of a commercial 20% Pt / C catalyst, and the Pt / C catalyst can be used in the field of proton exchange membrane fuel cells.

The embodiment of the invention relates to the field of energy storage, and provides a secondary battery and a preparation method thereof, an energy storage system and electric equipment. The negative electrode active material comprises a silicon-based material, honeycomb porous graphite and a polypyrrole layer, the surface of the honeycomb porous graphite is coated with the polypyrrole layer, the silicon-based material is embedded in pores of the honeycomb porous graphite, and the silicon-based material comprises silicon particles, a poly N-isopropylacrylamide layer and a disulfide bond-containing polyaniline layer. The poly (N-isopropylacrylamide) layer and the disulfide bond-containing polyaniline layer are coated on the surfaces of the silicon particles, the poly (N-isopropylacrylamide) layer is positioned between the silicon particles and the disulfide bond-containing polyaniline layer, and the honeycomb porous graphite comprises a graphite flake and a carbon layer which is positioned on the surface of the graphite flake and is of a honeycomb pore structure. The secondary battery formed by assembling the negative electrode active material disclosed by the invention has relatively high cycling stability, high temperature resistance, rate capability, gram volume and safety.

The invention discloses a lithium manganese iron phosphate positive electrode material coated with a carbon layer based on a CVD (chemical vapor deposition) method and a preparation method, the preparation method comprises the following steps: forming a uniform carbon coating layer on a lithium manganese iron phosphate precursor based on a CVD coating process, mixing the lithium manganese iron phosphate precursor with the uniform carbon coating layer and a lithium salt, and carrying out co-sintering, and the lithium salt can permeate through the carbon layer to form a lithium-doped uniform carbon coating layer. According to the method, the coating effect is improved, the problem that uniform coating cannot be formed on the surface of the precursor in a traditional carbon coating process is effectively solved, precipitation of trivalent manganese ions at a high temperature can be slowed down, the problem that the capacity exertion is reduced due to the fact that an amorphous carbon layer formed by a CVD cracking coating process affects lithium ion deintercalation is solved, and the performance of the lithium ion battery is improved. The safety and the service life of the battery are improved.

The invention discloses a high-conductivity carbon-coated lithium iron phosphate positive electrode material and a preparation method thereof, and relates to the technical field of lithium iron phosphate positive electrode materials, the high-conductivity carbon-coated lithium iron phosphate positive electrode material comprises a spherical lithium iron phosphate matrix, modified lithium niobium vanadate uniformly coating the exterior of the nanoscale spherical lithium iron phosphate matrix, and a composite carbon layer uniformly coating the exterior of the modified lithium niobium vanadate; wherein the spherical lithium iron phosphate matrix has a smaller specific surface area, so that the reduction of side reaction is facilitated, and the interface impedance can be reduced; the modified lithium niobium vanadate can improve the electronic conductivity of the positive electrode material and the diffusion rate of lithium ions; an organic carbon source in the outermost composite carbon layer is carbonized to form a continuous amorphous carbon layer which uniformly coats the surfaces of the particles, so that a basic electron channel is provided, and side reaction of an electrolyte is inhibited; the inorganic carbon source constructs a three-dimensional conductive skeleton, and a long-range conductive network is formed through the bridging effect of nanowires / sheets, so that the interface contact resistance is reduced, and the conductivity of the positive electrode material is improved.

The invention discloses a glass fiber reinforced PA12-PA6T composite material and a preparation method thereof, the composite material comprises the following components by weight: 40%-65% of PA12 resin, 10%-15% of PA6T resin, 10%-20% of glass fiber, 10%-20% of a compound flame retardant, 5%-10% of a CTI improver, 1.5%-5% of an antioxidant, and 1.5%-5% of a compatilizer. According to the invention, the PA12 / PA6T composite material is reinforced and modified by using the surface-modified glass fiber, the glass fiber can be uniformly dispersed in the resin and has good interfacial compatibility with the resin, and the mechanical properties are also improved. The compounded flame retardant has good dispersity in resin, a combustion carbon layer is migrated to the surface of a resin carbon layer, and the combustion carbon layer and the resin carbon layer are combined to form a more compact carbon layer, so that heat conduction between a polymer and a heat source is more favorably blocked, the flame retardance of the composite material is effectively improved, and the glowing filament of the material is obviously improved. And the compounded CTI auxiliary agent can enable the resin to be stacked in a discontinuous form, and is beneficial to improving the tracking index of the material.

The invention discloses a lithium ion battery negative pole piece, a preparation method thereof and a lithium ion battery, and belongs to the technical field of lithium ion battery electrode materials. The lithium ion battery negative electrode plate provided by the invention comprises a negative electrode current collector; the graphite layers are arranged on the surfaces of the two sides of the negative electrode current collector; the graphite layer comprises graphite particles, a conductive agent and a binder; the hard carbon layer is arranged on the surface of one side, far away from the negative electrode current collector, of the graphite layer; the hard carbon layer comprises hard carbon particles, a conductive agent and a binder; wherein the graphite layer and the hard carbon layer meet the relational expression: 1.4 < = rho1 * D1 + rho2 * D2 + PD < = 1.75. According to the invention, through proper design of the composite layer structure, the surface density, the compaction density and the particle sizes of the graphite particles and the hard carbon particles, the rapid charging performance of the lithium ion battery is improved, and meanwhile, relatively high energy density is kept; and the negative pole piece also has relatively good flexibility, so that the problems of breakage and powder falling in the processing process are relieved.

Various embodiments of improved process flows and methods are provided herein for etching high aspect ratio (HAR) features in carbon-containing hard mask layers. In the disclosed embodiments, the improved process flows and methods combine sidewall passivation and mask de-clogging steps in a single plasma process step to improve throughput when etching HAR features (such as vias, contact holes, trenches, etc.) within a carbon-containing hard mask layer. In doing so, the improved process flows and methods disclosed herein protect the sidewall surfaces of the carbon-containing hard mask layer and prevent bowing during the HAR etch process, while also reducing processing time and improving throughput.

The invention discloses a silicon-carbon composite negative electrode material, a negative electrode plate, a preparation method and application. The silicon-carbon composite negative electrode material is of a double-coating structure and sequentially comprises inner core silicon, a lithium phosphate layer and a fluorine-containing carbon layer from inside to outside, and the mass ratio of the lithium phosphate layer to the inner core silicon is (1-5): 100. When the composite material is applied to a lithium ion battery, the core silicon and the specific double coating layers can improve the fast charging performance and the first effect while optimizing an ion transmission path; a specific double-coating structure can be used as a buffer layer, stress generated by volume expansion of silicon can be released, and pulverization of particles is avoided; and moreover, LiF with high ionic conductivity and higher mechanical strength and an SEI film with more stable regulation and control are formed through reaction with an electrolyte, so that the structural integrity of the material is kept, and the cycle performance of the material is improved.

The invention relates to an outdoor anti-aging PP plate and a preparation method thereof, and belongs to the technical field of high polymer materials. The outdoor anti-aging PP plate comprises the following components in parts by weight: 40-80 parts of PP resin, 10-20 parts of glass fibers, 1-5 parts of an anti-aging modifier, 0.2-3 parts of a modified flame retardant, 0.1-1 part of a lubricant and 0.1-0.5 part of an antioxidant, hydroxybenzophenone in the modified anti-aging agent generates thermal vibration and releases energy when absorbing ultraviolet rays and being irradiated by the ultraviolet rays, and cooperates with butyltrimethoxysilane to protect the material from being damaged by the ultraviolet rays, and a maleimide group improves the glass transition temperature and the melting point and reduces the influence of high-temperature thermal aging; a B-O-C carbon layer is formed at a high temperature under the synergistic effect of boron and phosphorus of the modified flame retardant, flame-retardant gas is released, and the modified flame retardant and phosphorus-oxygen double bonds are synergistically flame-retardant, so that the flame-retardant property is remarkably improved; the outdoor anti-aging PP plate prepared by the invention not only has excellent anti-aging performance, but also has a good flame-retardant effect.

The invention relates to a high-compaction lithium iron phosphate positive electrode material, a preparation method thereof and a lithium ion battery, and belongs to the technical field of batteries, the method adopts a two-step synthesis method, the first step adopts ferrous phosphate high-grinding sintering to prepare first-sintering large particles, and adopts in-situ doped iron phosphate low-grinding to prepare first-sintering small particles; 2, performing high grinding on the first-fired large particles, performing low grinding on the first-fired small particles, accurately controlling the sizes of the small particles, and stripping C3N4 through grinding to form g-C3N4; the large and small particles are mixed according to a certain mass ratio, and then secondary sintering is carried out to prepare the high-compaction high-capacity long-circulation lithium iron phosphate material, the advantages of different precursors are utilized, the particle composition is optimized, and the roundness of the large and small particles is better; meanwhile, the nitrogen-doped carbon layer is prepared by taking defect-type graphene and high-molecular organic nitride which are converted from C3N4 in a secondary sintering process as carbon sources, so that the conductivity and the cycle performance of the material are improved.

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.

The invention discloses a composite coated silicon-carbon negative electrode material as well as a preparation method and application thereof, and relates to the technical field of lithium ion batteries. The method comprises the following steps of: oxidizing and etching graphite in mixed gas of air and nitrogen at the temperature of between 400 and 500 DEG C to form graphite oxide; the preparation method comprises the following steps: dispersing water-soluble asphalt, graphene, nano silicon, melamine and monoammonium phosphate in water to form a composite liquid; and then mixing the composite liquid with graphite oxide, and then carrying out carbonization treatment. The high-performance silicon-carbon composite negative electrode material is prepared through graphite oxidation etching and a composite coating process, nano silicon is uniformly dispersed in carbon pores which are stably combined on the surface of graphite and have rich mesoporous structures, graphene and a nitrogen-doped carbon layer form a three-dimensional conductive network, and the composite negative electrode material is applied to lithium ion batteries and can be applied to lithium ion batteries. And the lithium ion battery has good low-temperature charging proportion, first efficiency and cycle performance.