953 results about "Silicon particle" 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 metal matrix composite microstructure strengthening simulation method and system, and relates to the technical field of composite mechanical property simulation, and the method comprises the following steps: establishing a polycrystalline aluminum matrix atomic model and a spherical silicon nitride particle strengthening phase atomic model unit; embedding the spherical silicon nitride particles into the polycrystalline aluminum matrix according to the target embedding position coordinates, and integrating to generate an atomic scale structure model; according to the method, an embedded atom potential function is adopted to describe interaction among atoms in a polycrystalline aluminum matrix, a Tersoft potential function is adopted to describe covalent bond interaction among atoms in spherical silicon nitride particles, and a Lennard-Jones potential function is adopted to describe interaction among heteroatoms at a Si3N4 / Al interface; based on the interaction potential between atoms, molecular dynamics simulation is adopted for conducting uniaxial stretching simulation on the atomic scale structure model, mechanical property parameters of the particle reinforced metal matrix composite are obtained through calculation, and a visualization method is combined for analyzing the microcosmic strengthening mechanism of the particle reinforced metal matrix composite.

A slurry for use to form or repair a silicon carbide coating is provided. In one aspect, the slurry includes solid particles and a carbonaceous resin. The solid particles include silicon carbide particles, silicon particles, and carbon particles. A method of fabricating a silicon carbide coating is also provided. In one aspect, the method includes applying the slurry, heating the slurry, and forming the silicon carbide coating from the solid particles and the carbonaceous resin. A method of repairing a silicon carbide coating is also provided. In one aspect, the method includes applying the slurry to a damaged region of the silicon carbide coating, heating the slurry, and repairing the silicon carbide coating with the solid particles and the carbonaceous resin in the damaged region.

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 relates to a silicon-carbon composite material with a porous structure and a preparation method thereof, and the silicon-carbon composite material with the porous structure comprises an N / P co-doped porous carbon skeleton with micropore, mesopore and macropore channel networks, and amorphous or low-crystalline nanometer silicon particles which are uniformly loaded in the porous carbon skeleton and have the average particle size of 15-40nm, the mass percent of silicon in the composite material is 40-60%, and good interface bonding is formed between silicon and carbon. The preparation method mainly comprises the following steps: firstly, preparing an N / P co-doped porous carbon skeleton through a template method in combination with high-temperature carbonization and N / P source co-pyrolysis; and hydrolyzing an organic silicon source in the carbon skeleton to form silicon dioxide, and performing low-temperature metal thermal in-situ reduction to obtain the nano-silicon loaded composite material. Through a unique porous carbon skeleton design and a precise in-situ composite strategy of nano silicon, the prepared material shows high specific capacity, high initial coulombic efficiency and excellent cycling stability and rate capability when being used as a negative electrode of a lithium ion battery.

The present invention relates to a silicon-carbon composite, a preparation method therefor, and an anode active material comprising same. The silicon-carbon composite includes silicon particles, silicon oxides, magnesium compounds, and carbon. As a molar ratio (O / Si) of oxygen (O) atoms to silicon (Si) atoms in the silicon-carbon composite satisfies 0.01 to 0.60, when the silicon-carbon composite is applied to an anode active material, the discharge capacity, initial efficiency, and capacity retention ratio after cycles of a lithium secondary battery may be simultaneously improved.

The invention provides a phenolic resin-based spherical silicon-carbon composite material as well as a preparation method and application thereof, and belongs to the technical field of lithium battery materials. The preparation method comprises the following steps: preparing spherical phenolic resin by adopting a suspension polymerization method, curing to obtain phenolic resin microspheres, preparing porous carbon spheres by taking the phenolic resin microspheres as a carbon precursor in a carbonization and alkali activation manner, carrying out CVD vapor deposition on nano silicon, and carrying out carbon coating to obtain the phenolic resin-based spherical silicon-carbon composite material. The phenolic resin is utilized to form a highly cross-linked network structure after curing, the carbon spheres obtained after carbonization have good mechanical strength and rigidity, the porous structure of the porous carbon spheres provides a volume change buffering structure for nano-silicon, the lithium ion path is shortened, the spherical structure is beneficial to uniform dispersion, nano-silicon particles are prevented from gathering, and the performance of the lithium ion battery is improved. And the porous carbon spheres with high specific surface area can also improve the interface reaction activity, so that the problems of high volume expansion, low conductivity and slow ion diffusivity of silicon are solved.

The invention relates to the technical field of lithium ion battery negative electrode materials, and discloses a preparation method and application of a high-efficiency silicon-carbon composite graphite material, and the preparation method comprises the following steps: S1, carrying out porosity and size regulation and control on silicon particles: carrying out ball milling on industrial-grade silicon powder to obtain nano silicon particles, and carrying out acid etching to form a porous structure; s2, functional surface treatment and interface optimization: introducing functional molecules to the surfaces of the silicon particles and coating a layer of ultrathin SiO2 protective film; and S3, carbon coating and flexible protection layer construction: performing pyrolysis on the porous silicon particles by using a carbon source to form a uniform carbon coating layer which is applied to a lithium ion battery negative electrode material, and the lithium ion battery is used for an electric vehicle, a power grid energy storage system and portable electronic equipment. Through the collaborative design of the flexible protection layer, the double-layer carbon coating and the gradient coating, the technical bottlenecks of the silicon-based negative electrode material in the aspects of long cycle stability, high rate performance and interface chemical stability are systematically solved.

The invention relates to the technical field of electrochemical energy storage devices, in particular to a silicon-carbon negative electrode material, a negative electrode plate, an electrochemical device and an electronic device, and mainly comprises a core material and a coating material, the core material comprises silicon particles, the coating material comprises a porous carbon material doped with indium particles, and the coating material comprises a porous carbon material doped with indium particles. The average pore size of the coating material ranges from 10 nm to 20 nm, and the porosity of the coating material ranges from 35% to 45%. According to the silicon-carbon negative electrode material provided by the invention, the coating material has the effects of buffering and inhibiting silicon volume expansion, so that pulverization of the silicon-carbon negative electrode material is inhibited, and the problem of volume expansion of a battery is solved.

The invention provides a sidewalk antiskid terrace material and a construction process thereof, and belongs to the technical field of terrace material manufacturing. The sidewalk antiskid terrace material is prepared from the following components: epoxy resin, polysiloxane elastic resin, fluorocarbon resin, modified covalent organic framework nanosheets, boron nitride nanotubes, nano silicon nitride particles, nano silicon dioxide, nano zinc oxide, a modified flame retardant, attapulgite, a curing agent, an accelerant, a flatting agent, a coupling agent and a dispersing agent. According to the sidewalk antiskid terrace material, various high-performance resins are compounded with the nano filler to form a coating with a compact and uniform structure, so that the mechanical strength and wear resistance of the terrace are remarkably improved. In addition, due to the application of the modified flame retardant, the floor has a good flame-retardant effect, and the safety is improved. The whole formula and the construction process are scientific and reasonable, strong adhesion of the coating is ensured, construction is simple and convenient, curing is sufficient, and the coating is suitable for long-term use of outdoor sidewalks and has attractive appearance and practicability.

The invention discloses a preparation method and application of a carbon-interspersed superfine silicon network composite structure. According to the method, a carbon skeleton with a low specific surface area is used as a carrier, after high-temperature air oxidation pretreatment, nano silicon particles are loaded through vapor deposition or a mixing method, and the battery is assembled for in-situ electrochemical induction. In the induction process, silicon particles are subjected to lithiation fusion-lithium removal bonding to form a continuous network, a carbon phase is interspersed in the continuous network to limit silicon agglomeration, and a double-phase interspersed structure with a silicon network skeleton size of 5-40nm is obtained. According to the embodiment of the invention, as a lithium ion battery negative electrode, the specific capacity reaches 1507mAhg <-1 > under 0.2 Ag <-1 >, the 100-time cycle capacity retention ratio reaches 94.8%, and the 50-time cycle capacity retention ratio of a whole battery matched with LiFePO4 is 98.1%. A high-cost porous carbon carrier is abandoned, the problems of nano silicon agglomeration and side reaction are solved, and the method is compatible with industrial production.

A lithium-ion secondary battery having excellent discharge characteristics even in a low-temperature environment is provided. The lithium-ion secondary battery includes a positive electrode, a negative electrode, and an electrolyte solution. The positive electrode includes lithium cobalt oxide with a median diameter (D50) of greater than or equal to 1 μm and less than or equal to 12 μm. The lithium cobalt oxide contains magnesium in its surface portion. The negative electrode includes a graphite particle, a silicon particle, and a polymer including a carboxy group. The electrolyte solution contains a mixed solvent of a fluorinated cyclic carbonate and a fluorinated chain carbonate.

The invention discloses a method for preparing a silicon-carbon composite negative electrode material through an electrostatic self-assembly technology, and belongs to the technical field of lithium ion battery negative electrode materials. According to the invention, lignin is used as a biomass carbon source and lauryl sodium sulfate (SDS) and poly (diallyldimethylammonium chloride) (PDDA) are used as activators through a simple electrostatic self-assembly technology; a proper amount of nano silicon and PDDA are subjected to in-situ adsorption, and lignin and SDS are subjected to in-situ adsorption; a self-assembly process is carried out through the positive and negative charge attraction effect among colloidal particles, so that effective compounding of the nano silicon particles and the biomass carbon is realized; and performing vacuum drying, and performing one-stage sintering in a tubular furnace to obtain the silicon-carbon composite negative electrode material. Based on the problems of non-uniform particle size, easy agglomeration and great abrasion of a silicon-carbon composite material in a traditional mechanical synthesis technology, the invention improves the compounding efficiency of the silicon-carbon material and improves the problems of volume expansion of a silicon negative electrode, slow migration rate of lithium ions, poor cycle performance and the like.

The invention relates to a silicon-carbon negative electrode material and a preparation method thereof. The silicon-carbon negative electrode material comprises a carbon skeleton, silicon particles distributed in pores of the carbon skeleton and a carbon layer coating the carbon skeleton, wherein the carbon skeleton adopts porous carbon, and the carbon layer is of a double-layer gradient coating structure. According to the silicon-carbon negative electrode material and the preparation method thereof, by controlling the deposition mode, deposition temperature, deposition time and the like of the silicon source gas and the coating mode, coating flow, coating time and the like of the coating gas, uniform deposition of silicon particles in pores of a carbon skeleton and uniform coating of a gradient coating type carbon layer are realized; the growth of silicon grains and the formation of rich silicon on the surface are inhibited, the gas production of the material is reduced, the tap density of the material is improved, the tar residue in the material is eliminated, and the comprehensive electrochemical performance is considered.

The present application relates to a negative electrode active material and a preparation method therefor, a negative electrode sheet, a secondary battery, and an electric device. The negative electrode active material comprises expanded graphite, a porous carbon layer, and silicon particles; the expanded graphite comprises a plurality of graphite layers; the porous carbon layer is at least distributed on an interlayer surface of one graphite layer, and the silicon particles are at least distributed in pore channels of porous carbon of the porous carbon layer.

The invention provides a silicon-carbon negative electrode material, a preparation method thereof and a secondary battery. The silicon-carbon negative electrode material comprises a carbon skeleton, nano silicon particles and a carbon coating layer, wherein the carbon skeleton is a complex of carbon nanotubes and amorphous carbon. The amorphous carbon has a hierarchical pore structure, and the hierarchical pore structure comprises 65-85% of micropores and 15-35% of mesopores. At least part of the nanometer silicon particles are contained in the grading hole structure, and the carbon framework is coated with the carbon coating layer. The silicon-carbon negative electrode material has a carbon skeleton with a hierarchical pore structure, volume expansion of nano silicon can be effectively relieved, the cycle performance of the material is improved, and a three-dimensional conductive network constructed by the carbon nanotubes is also beneficial to improvement of the rate capability of the material.

The invention provides a negative electrode material and a preparation method thereof, and a battery, the negative electrode material comprises an active substance, the active substance comprises a carbon matrix and silicon particles, the carbon matrix has holes, and at least part of the silicon particles are distributed in the holes of the carbon matrix; the negative electrode material contains an oxygen element and a nitrogen element, the mass content of the oxygen element is A%, and the mass content of the nitrogen element is B%; the powder conductivity of the negative electrode material is PS / m and meets the following relation: (A + B) / P is less than or equal to 3. According to the negative electrode material provided by the invention, the gas production phenomenon of the negative electrode material can be reduced on the premise of keeping relatively high electronic conductivity.

A method for manufacturing an article containing silicon carbide as a main component includes a step of forming a layer of a raw material powder and a step of irradiating the layer of the raw material powder with a laser on the basis of data from a three-dimensional model, in which the steps are performed multiple times, the raw material powder contains silicon carbide particles having a particle size larger than 200 nm and metallic silicon particles having a particle size larger than 200 nm, and the metallic silicon particles have a number-average particle size smaller than a number-average particle size of the silicon carbide particles.

The invention relates to the technical field of lithium ion batteries, in particular to a silicon-based negative electrode material and a preparation method and application thereof. The silicon-based negative electrode material comprises slurry and a copper sheet, and the mass ratio of the slurry to the copper sheet is (0.5-1): 8.4; the slurry is prepared from silicon powder, sodium alginate, a conductive agent, poly (3, 4-ethylenedioxythiophene) / polystyrolsulfon acid, an initiator and a solvent; the initiator is a polar solvent. The structural stability of the silicon-based negative electrode material in the lithiation / delithiation process is realized by constructing a three-dimensional (3D) cross-linked network structure on the surface of the silicon particles and optimizing a self-repairing SEI layer interface. And the network structure can effectively inhibit volume expansion of the silicon negative electrode material and maintain the integrity of the silicon negative electrode morphology, so that the specific capacity and the cycle performance of the lithium ion battery are remarkably improved.

The invention relates to the field of lithium ion battery silicon-carbon negative electrode materials, and discloses a graphitized graded porous carbon skeleton and a preparation method and application thereof.According to the method, in the precursor carbonization stage, a mesoporous structure is introduced through volatilization of a pore-forming agent, then a carbonized material is activated to form micropores, and the carbon skeleton is prepared; a micro-mesoporous structure is introduced into the porous carbon material in a two-step combined activation manner, so that the pore channel connectivity is improved. Meanwhile, by utilizing the characteristic of low-temperature catalytic graphitization of the catalyst, the catalyst is introduced in the activation process, and catalytic graphitization of the carbon material is completed while activation is performed. The porous carbon material prepared by the method has an adjustable connectivity micro-mesoporous structure and a high graphitization degree, and the silicon-carbon composite material prepared by taking the porous carbon material as a framework is uniform in silane deposition, accurate in silicon particle limiting, good in electrolyte wettability and good in ionic conductivity and electronic conductivity. Therefore, the volume expansion of the silicon negative electrode material is effectively reduced, and the rate capability of the silicon negative electrode material is improved.

The invention discloses a porous silicon-carbon composite negative electrode material, a one-step preparation method, a lithium ion battery and application, and belongs to the technical field of lithium ion battery materials, the method comprises the following steps: mixing a silicon source, magnesium powder, a carbon source and a soluble pore forming agent to obtain mixed powder; performing high-energy mechanical ball milling on the mixed powder in an inert atmosphere, and performing acid pickling, high-temperature carbonization treatment, cooling, water washing, suction filtration and drying to obtain the porous silicon-carbon composite negative electrode material; the porous silicon-carbon composite negative electrode material comprises a porous shell formed by amorphous porous carbon and a porous core formed by silicon nanoparticles embedded in the porous shell, the mechanical collision energy generated in the high-energy mechanical ball milling process triggers the low-temperature magnesiothermic reduction reaction between the silicon source and the magnesium powder, the carbon source is attached to the surfaces of silicon particles while the silicon particles are generated, and silicon synthesis, carbon coating and pore forming are synchronously achieved. The silicon-based negative electrode has the advantages of high initial coulombic efficiency, high specific capacity, excellent cycle stability and rate capability, and effectively solves the problems of volume expansion and large-scale preparation of the silicon-based negative electrode.

The invention relates to the technical field of batteries, in particular to a silicon-carbon negative electrode material and a lithium ion secondary battery. The silicon-carbon negative electrode material comprises silicon-carbon particles, the silicon-carbon particles comprise a matrix, and the matrix comprises a porous carbon matrix and silicon particles located in internal holes of the porous carbon matrix; the porous carbon substrate is provided with open pores and closed pores, the open pores contain silicon particles, the closed pores contain an element K, and based on the total mass of the silicon carbon particles, the mass content of the element K is 50 ppm to 1000 ppm; the silicon-carbon particles comprise halogen, and based on the total mass of the silicon-carbon particles, the mass content of the halogen is 50 ppm to 2000 ppm; the silicon carbon particles and deionized water are mixed according to the mass ratio of 1: 10 to obtain an aqueous solution, the pH value of the aqueous solution at 25 DEG C is pH 1, and the pH 1 is 6-8. Comprising the silicon-carbon negative electrode material disclosed by the invention has the advantages that the expansion rate is improved, and the rate capability and the cycle performance are improved.

The invention relates to the technical field of lithium ion batteries, and particularly discloses a silicon-carbon-based composite material, a preparation method thereof and application of the silicon-carbon-based composite material in a lithium ion battery. The silicon-carbon-based composite material is prepared by taking a carbon nanotube as a seed crystal through a silicon-carbon co-deposition reaction, and no nanoscale pores exist between a disordered carbon matrix and silicon particles of the silicon-carbon-based composite material. According to the structural characteristics, the transmission bottleneck problem of a traditional CVD silicon carbon material is fundamentally solved, the dynamic performance of the material is remarkably improved, and the situation of voltage and capacity diving at the discharge tail end is thoroughly avoided. The continuous production of the silicon-carbon-based composite material is realized, the production efficiency of the lithium ion battery is remarkably improved, the production cost of the lithium ion battery is reduced, the dependence on special raw materials is reduced, the limitation of customized porous carbon production is avoided, and the method has obvious economic and market advantages and is worthy of popularization and application. The invention provides a negative electrode material with excellent comprehensive performance for the lithium ion battery, and has great significance for promoting the technical development of the lithium ion battery.

The invention provides a silicon-carbon negative electrode material with a core-shell structure and a preparation method and application of the silicon-carbon negative electrode material. The preparation method comprises the following steps: sequentially preparing a sacrificial layer and a carbon coating layer for coating silicon particles on the surfaces of the silicon particles to form a carbon-coated silicon material; etching the carbon-coated silicon material by adopting an etching agent capable of etching the sacrificial layer, and removing the sacrificial layer in the carbon-coated silicon material to form a silicon-carbon material; dipping the silicon-carbon material in a metal precursor solution, taking out the silicon-carbon material, and drying the silicon-carbon material, wherein simple substances of metal elements in the metal precursor and / or silicides of the metal elements can catalyze the generation of the carbon nanotubes; heating the dried silicon-carbon material in a reducing gas atmosphere to form a catalyst on the surfaces of the silicon particles, the catalyst comprising simple substances of metal elements and / or silicides thereof; and depositing carbon nanotubes on the basis of the elementary substance of the metal element and / or the silicide thereof. The high-rate cycle performance of a battery prepared from the core-shell structure silicon-carbon negative electrode material is obviously improved.

The invention relates to the technical field of batteries, in particular to a core-shell material, a preparation method, a negative electrode material and a battery. The method provided by the invention comprises the following steps: processing metal salt raw materials of aluminum, iron, cobalt, nickel, zinc and lanthanum into a high-entropy metal oxide; taking silicon particles as a core layer, gasifying a high-entropy metal oxide, and depositing the gasified high-entropy metal oxide on the surface of the core layer to form a coating layer so as to obtain Si (at) HEO particles; depositing a zinc layer on the Si-coated HEO particles to form a growth layer on the surface of the coating layer, dispersing the Si-coated HEO particles in a Si-coated HEO solvent, adding a zinc nitrate aqueous solution and a 2-methylimidazole aqueous solution for reaction, and growing a shell layer on the growth layer on the surface of the coating layer to obtain Si-coated HEO-ZIF particles; and mixing the acidic solution and the Si (at) HEO (at) ZIF particles to form a secondary pore channel, and separating to obtain the core-shell material. The core-shell material provided by the invention solves the problems of low stress dispersion efficiency, low ion transmission and poor volume expansion rate of the existing core-shell material.

The present invention relates to a photovoltaic crystalline silicon waste treatment technology, and in particular to a method for preparing a carbon-coated porous silicon-based lithium battery negative electrode material from photovoltaic crystalline silicon waste, comprising the following steps: 1) reducing the size of the photovoltaic crystalline silicon waste to a submicron level; 2) dissolving the treated photovoltaic crystalline silicon waste in a CH3CH2OH solution of NaOH, filtering, washing, drying, sintering and oxidizing the product, and finally etching it with a NaOH solution at room temperature to obtain porous silicon particles; 3) mixing the obtained porous silicon particles and CaCO3 in deionized water, ultrasonically dispersing to obtain a self-assembled porous silicon-CaCO3 particle precursor, centrifuging and washing to complete solid-liquid separation, and pyrolyzing the precursor with citric acid as a carbon source under an inert gas atmosphere to obtain the carbon-coated porous silicon-based lithium battery negative electrode material. The method of the present invention can not only effectively utilize the crystalline silicon waste generated in a silicon wafer cutting process, but also reduce the cost of preparing the silicon negative electrode material. At the same time, the design of the porous carbon coating structure also solves the problem of insufficient stability of the silicon-based lithium battery negative electrode material.

The invention discloses a preparation method of a high-volume-fraction multi-scale silicon carbide reinforced aluminum-based composite material with a self-lubricating function, and relates to a preparation method of a silicon carbide reinforced aluminum-based composite material. The problem that the strength and rigidity are low due to the fact that the content of solid lubricating materials in aluminum-based self-lubricating materials is high is solved. The preparation method comprises the following steps: mixing the silicon carbide particles and the carbon nanotubes, putting into a mold, compacting by vibration, and performing cold pressing to obtain a blank; smelting the matrix metal ingot to obtain molten aluminum; the molten aluminum is transferred into a mold containing the prefabricated body to be subjected to pressure infiltration, and the high-volume-fraction multi-scale silicon carbide reinforced aluminum matrix composite with the self-lubricating function is obtained; by adding the high-rigidity carbon nanotubes, the rigidity and strength of the material can be remarkably improved, and the composite material has a good self-lubricating effect. The micron-sized silicon carbide and the nano-sized carbon nanotubes are adopted to play a synergistic effect of different scales, so that the strength and the rigidity of the material are effectively improved, and the material has relatively high comprehensive performance and good processability.

The invention discloses a silicon-carbon composite material as well as a preparation method and application thereof, and belongs to the field of lithium ion batteries. The silicon-carbon composite material comprises carbon fibers and a composite material formed by coating silicon with single-walled carbon nanotubes. The composite material of the single-walled carbon nanotube coated silicon is embedded in the carbon fiber; the single-walled carbon nanotube-coated silicon composite material comprises silicon particles and a single-walled carbon nanotube net-shaped coating layer, the single-walled carbon nanotube net-shaped wrapping layer is tightly wrapped on the outer surfaces of the silicon particles; the single-walled carbon nanotube net-shaped wrapping layer is of a two-dimensional net bag type structure formed by assembling non-tube-bundle type single dispersed oxidized single-walled carbon nanotubes serving as assembling elements. The composite material has excellent electrochemical performance.

The invention discloses a high-magnification low-expansion modified silicon-carbon composite material and a preparation method and application thereof, the modified silicon-carbon composite material is of a particle structure and comprises a silicon-carbon material serving as an inner core and a fluorine-containing conductive polymer layer coating the surface of the silicon-carbon material; the silicon-carbon material is obtained by coating the surfaces of silicon particles with carbon layers; the fluorine-containing conductive polymer layer is obtained by initiating polymerization of a first monomer and a second monomer, and the first monomer is a fluorine-containing polymer monomer. The preparation method comprises the following steps: putting the silicon-carbon material, a first monomer and a second monomer into a hydrothermal reaction kettle, adding a mixed solvent of water and ethanol, heating while stirring, adding an initiator after heating to a target temperature, preserving heat, reacting, cooling, carrying out suction filtration, washing with water, and drying to obtain the fluoro-coated silicon-carbon material, namely the modified silicon-carbon composite material. According to the application, the modified silicon-carbon composite material serves as a negative electrode active component and is mixed with a conductive agent, a binding agent and a dispersing agent, so that the negative electrode coating slurry for preparing the negative electrode plate of the lithium ion battery is formed.

A process for producing a porous host structure or a powder mass of multiple porous particulates containing silicon oxide (SiOx) therein, comprising (a) providing a porous host structure having a volume fraction of pores from 5% to 99.9%, wherein the porous host structure is selected from a carbonaceous, graphitic, graphene, or metallic material; (b) catalytically vaporizing Si from a mixture of a catalyst and elemental Si or a Si-containing material to form a vapor phase of Si or a precursor to Si; (c) immediately directing the vapor phase into pores of the porous host structure and facilitating the vapor phase to form solid Si particles or coating deposited in the pores to form a Si-impregnated porous host structure; (d) exposing the Si to an oxidizing environment to obtain SiO2-coated Si particles / coating or SiOx; and (e) optionally breaking and reducing the SiOx-impregnated porous host structure into smaller porous particulates.