1186results about "Silicon" patented technology

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 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 relates to the technical field of lithium ion batteries, in particular to a lithium-doped silicon-carbon composite material, a preparation method thereof, a negative plate and a lithium ion battery. The preparation method of the lithium-doped silicon-carbon composite material comprises the following steps: carrying out reduction reaction and activated pore-forming on a mixed material containing a carbon source, an organic pore-forming agent, a lithium supplement agent and a reducing agent to obtain lithium-doped porous carbon; performing first deposition on the lithium-doped porous carbon and mixed gas containing an inorganic lithium compound and an organic lithium compound; carrying out second deposition on the material obtained after the first deposition and silane gas to obtain a lithium compound doped silicon carbon precursor material; and mixing the lithium compound doped silicon carbon precursor material, an organic metal compound, asphalt and an organic solvent, performing spray drying, and then performing carbonization. According to the preparation method, the initial efficiency and the power performance of the silicon-carbon composite material can be 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 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 technical field of lithium ion batteries, and particularly relates to a preparation method of a graded ordered silicon-carbon negative electrode material for a lithium ion battery, which comprises the following steps: (S1) mixing phenolic resin and a template agent, calcining, and etching to obtain porous carbon containing macropores; (S2) carrying out cracking and carbon coating on the silicon source gas to obtain nano crystalline silicon containing a carbon coating layer; (S3) mixing the porous carbon with the nano crystalline silicon containing the carbon coating layer, and then carrying out ultrasonic vibration, so that macropores of the porous carbon are filled with the nano crystalline silicon to obtain a silicon-carbon composite material I; (S4) treating the silicon-carbon composite material I by using a carbon-containing sealing agent, and then activating to obtain a silicon-carbon composite material II; and (S5) carrying out vapor phase silicon deposition on the silicon-carbon composite material II to fill the amorphous silicon in the pores of the porous carbon, and then carrying out carbon coating to obtain the graded ordered silicon-carbon negative electrode material. The silicon-carbon negative electrode material prepared by the invention is of a composite structure in which crystalline silicon and amorphous silicon are spatially and orderly distributed, so that the structural stability and the uniform distribution of silicon are realized.

The present application relates to the field of batteries and provides a silicon-carbon negative electrode material, a preparation method therefor, a negative electrode piece, an electrode, and an electric device. The silicon-carbon negative electrode material comprises porous carbon and silicon particles attached to the pore walls of the porous carbon, a crystal phase being present in the silicon particles, crystallinity being at least 90%, and the average crystal grain size of the silicon particles being less than 4 nm. The silicon-carbon negative electrode material can allow batteries to obtain better cycle stability and high initial Coulombic efficiency.

The invention relates to a silicon-carbon negative electrode material and a preparation method and application thereof, in particular to a liquid-phase in-situ polymerization coating-based silicon-carbon negative electrode material and a preparation method and application thereof, and the preparation method comprises the following steps: mixing a silicon-carbon composite precursor and a solvent according to a certain mass ratio, and uniformly stirring to form a solvent system; adding an organic carbon source into the solvent system, and uniformly stirring to form an organic precursor solution; carrying out hydrothermal reaction on the organic precursor solution, so that an organic carbon source is subjected to in-situ polymerization reaction on the surface of the silicon-carbon composite precursor to form a compact coating layer, and obtaining an intermediate product; and carrying out heat treatment on the intermediate product, discharging, and sieving to obtain the silicon-carbon negative electrode material based on liquid-phase in-situ polymerization coating, when the silicon-carbon negative electrode material is used for preparing a negative electrode plate and assembling the negative electrode plate into a lithium ion battery, the first-cycle coulombic efficiency and the cycle performance of the lithium ion battery can be improved.

The invention relates to the technical field of lithium ion battery negative electrode materials, in particular to a preparation process of a silicon-carbon coated negative electrode material which takes bamboo wood as a biomass carbon source and is combined with nano silicon and a dual carbon coating technology, and the preparation process comprises the following steps: step a, sol loading, step b, vacuum impregnation, step c, interface bonding, step d, inner layer coating and step e, outer layer coating. A silicon-carbon interface in-situ bonding technology and a double-layer carbon coating technology are utilized, a sol-gel method is adopted to construct a Si-O-C chemical bond on the surface of bamboo-based carbon, molecular-level anchoring of silicon particles (20-50 nm) on the surface of a carbon skeleton is achieved, the interface separation problem of traditional mechanical mixing is solved, meanwhile, inner-layer amorphous carbon (2-3 nm) is generated in cooperation with bamboo wood pyrolysis gas, and the surface of the bamboo-based carbon is separated. Then bamboo vinegar is carbonized to form an outer graphitized carbon shell (5-8nm), and the double carbon layers cooperate to inhibit volume expansion of silicon, so that the problem of volume expansion of silicon is solved, and the first charge-discharge efficiency of the battery and the capacity retention rate after circulation are effectively improved.

Disclosed are a nano silicon-carbon composite material, a preparation method therefor, and a use thereof. The nano silicon-carbon composite material comprises co-agglomerated nano silicon particles and nano carbon particles. The mass ratio of the nano silicon particles to the nano carbon particles is (45-60):(40-55). The nano silicon particles have an average particle size of 1-50 nm and a crystallite grain size of 1-10 nm. The nano silicon particles have varied crystal orientations and are freely combined with the nano carbon particles. In the nano silicon-carbon composite material, the nano silicon particles and the nano carbon particles are uniformly dispersed, and the particle size of the nano silicon particles is small. Moreover, due to the dispersion of the nano carbon, the phenomenon of agglomeration between the nano silicon particles can be reduced. When the composite material is applied to negative electrode materials and batteries, the phenomenon of electrochemical sintering can be effectively mitigated.

The invention belongs to the field of functional material preparation, and particularly relates to a preparation method of a silicon-yttrium-carbon composite lithium ion battery negative electrode material, which comprises the following steps: (1) dispersing silicon nanoparticles, polyvinylpyrrolidone and yttrium salt in a deionized water solution to form a mixed solution, carrying out ultrasonic vibration dispersion, and then carrying out magnetic stirring in a room temperature air atmosphere; (2) transferring the obtained solution to a glass culture dish, and performing freeze drying in a freeze dryer; (3) transferring the precursor obtained by drying into a crucible, and placing the crucible in a tubular furnace for high-temperature calcination to obtain a silicon-yttrium-carbon composite material; and (4) grinding and mixing the obtained product with sodium alginate, conductive carbon black and deionized water respectively, uniformly coating the surface of a copper foil with the mixture, and then performing drying, slicing and tabletting treatment to obtain a target product. The preparation method is simple in synthesis process, good in electrode cycling stability, stable in structure and excellent in electrochemical performance.

The invention provides a carbon material, application of the carbon material, a silicon-carbon composite material, a negative electrode and a battery, and particularly relates to the technical field of carbon materials and secondary batteries. The carbon material has the characteristics of a porous structure and graphitization at the same time, and has the following characteristics: i) the N2 adsorption pore volume is 0.4-2.0 cm < 3 > / g; ii) the N2 adsorption average pore size is 1.8 to 5.0 nm; and (iii) partial graphitization is carried out, disordered carbon and graphitized carbon are compounded, a diffraction peak P exists between 2theta = 25-30 degrees in an XRD (X-Ray Diffraction) pattern, and the grain size of P calculated according to a Scherrer formula is 2-40 nm. The invention also provides a silicon-carbon composite material, the silicon-carbon composite material comprises a porous carbon material and silicon nanoparticles, the porous carbon material comprises the carbon material provided by the invention, and the silicon nanoparticles are located in pore channels of the porous carbon material. The silicon-carbon composite material provided by the invention has the advantages of high capacity, high first efficiency and high cycle stability when being applied to the lithium ion secondary battery.

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 present disclosure provides methods for forming polymer brushes on Si and C-based - particles, thus, enabling easy large-scale production of polymer brush decorated particles. In particular, the improved methods allow for easy control of the graft-density due to the formation of a multifunctional layer on the particles. The disclosure also provides a Si and C-based - particle having a multifunctional base layer as well as a Si and C-based particle having a multifunctional base layer upon which polymer brushes are formed.

The invention relates to a particulate material and a method for preparing the same. The particulate material is composed of a plurality of composite particles. The composite particle comprises a porous particle skeleton, and the porous particle skeleton comprises micropores and / or mesopores. The total pore volume of micropores and mesopores measured by gas adsorption is in the range of 0.4 to 2.2 cm3 / g. The composite particle includes a plurality of electroactive material domains and a plurality of modified material domains disposed within an internal pore volume of a porous particle backbone. At least a portion of the modified material domains are located between adjacent electroactive material domains.

The invention provides a preparation method for preparing porous carbon based on an aerogel method, the porous carbon and application of the porous carbon, and belongs to the technical field of porous carbon material preparation. The preparation method comprises the following steps: mixing polyhydroxy phenol, aromatic aldehyde, acrylamide, graphene oxide and lithium salt according to a mass ratio of 100: (50-200): (5-30): (1-5): (1-5), carrying out hydrothermal reaction at 100-200 DEG C for 1-6 hours, and freeze-drying at-40 DEG C to obtain a hydrogel precursor; and carbonizing the precursor in organic heteroatom gas at 500-800 DEG C, mixing the intermediate with alkali according to the ratio of 100: (100-500), activating at 900-1100 DEG C, pickling and drying to obtain the porous carbon. The conductivity of the product is improved by means of graphene, lithium salt and heteroatoms, and the aerogel method obtains large aperture, has the characteristics of low impedance, high first efficiency and small charge-discharge expansion, and can be efficiently applied to silicon-carbon materials.

The invention relates to the technical field of lithium ions, in particular to a silicon-carbon negative electrode material and a preparation method thereof.The silicon-carbon negative electrode material comprises porous silicon particles, gradient carbon layers and carbon nanotubes, the surfaces of the porous silicon particles are coated with the gradient carbon layers, and the gradient carbon layers comprise inner-layer hard carbon and outer-layer soft carbon; the porous silicon particles and the carbon nanotubes are ball-milled and mixed to form a three-dimensional conductive skeleton. The preparation method of the silicon-carbon negative electrode material comprises the following steps: preparing porous silicon; mixing the porous silicon with phenolic resin, and carrying out segmented carbonization in an inert atmosphere; and ball-milling and mixing the carbonized porous silicon and carbon nanotubes to form a three-dimensional conductive skeleton. Through the collaborative design of the porous silicon particles, the gradient carbon layer and the carbon nanotube three-dimensional conductive skeleton, the problems of weak interface bonding, insufficient conductivity, easy collapse of the structure and the like of the existing silicon-carbon negative electrode material are successfully solved. According to the material, the advantage of high specific capacity of a silicon-based negative electrode is maintained, and meanwhile, the cycling stability and the rate capability are remarkably improved.

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 application provides a negative electrode material and a preparation method thereof and a secondary battery, and relates to the technical field of battery materials. The negative electrode material comprises a silicon-based inner core and a carbon layer coated on the surface of the silicon-based inner core, wherein the silicon-based inner core comprises nanosilicon and a silicate containing a metal element M; the negative electrode material is subjected to section analysis and energy spectrum analysis, and meets the conditions of k1<=10, k2<=5 and 0.1 The preparation method of the negative electrode material comprises the following steps: heating and evaporating pre-disproportionated silicon monoxide material and M metal source material to obtain silicon monoxide gas and metal source gas; mixing and condensing the two kinds of gas to obtain an inner core material; and performing carbon coating treatment to obtain the negative electrode material. In the negative electrode material prepared by the application, the metal silicate effectively separates the nanosilicon domain and the silicon oxide domain, and is uniformly distributed, and the negative electrode material has high initial efficiency and excellent cycle performance.

The invention discloses a photovoltaic waste silicon and recycled carbon composite granulation coating process, and relates to the field of new energy materials. According to the method, high-purity silicon waste sheets recovered from retired photovoltaic modules and carbon materials recovered from electronic wastes are subjected to composite granulation, and a carbon coating layer is formed through heat treatment. The preparation method specifically comprises the steps of raw material pretreatment, mixing, granulation forming, coating carbonization, post-treatment and the like, the prepared silicon-carbon composite particles have good conductivity and structural stability and can be used for lithium ion battery negative electrode materials, and efficient recycling of resources and environment-friendly production are achieved.

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 invention belongs to the technical field of lithium ion battery materials, and relates to a preparation method and application of an yttrium-doped porous silicon material, and the preparation method comprises the following steps: S1, preparing a silicon-yttrium alloy precursor; s2, mixing the silicon-yttrium alloy precursor with magnesium powder, and performing heat treatment; s3, nitridation reaction; and S4, carrying out acid etching. According to the YSi2 fine grain reinforced porous silicon-based material provided by the invention, a fine grain strengthening mechanism caused by grain boundary segregation in a structural material is introduced into a silicon negative electrode material, so that the intrinsic strength of the silicon material is improved, pulverization and crack propagation of the material are inhibited, and excellent cycle performance and outstanding rate capability are obtained; the invention provides a novel fine grain reinforced silicon negative electrode model, provides theoretical and experimental guidance for research and development of high-strength and high-specific-energy battery materials, solves the problems of low intrinsic strength, large volume expansion and poor conductivity of the silicon negative electrode material, and has the advantages of simple preparation process, short period, low energy consumption and no carbon, and can be produced on a large scale.

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 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 discloses a solid electrolyte-coated silicon-carbon composite material and a preparation method thereof, and is characterized in that a negative electrode material has a core-shell structure, the core is metal-doped porous carbon and nano silicon deposited in pores, and the shell is a solid electrolyte complex. The preparation method comprises the following steps: uniformly mixing an emulsifier, a phenolic compound, an aldehyde compound, a cross-linking agent, a metal salt of the cross-linking agent and a template agent, then adding an oxidizing agent for reaction, and preparing metal-doped porous carbon through heteroatom doping and activation; depositing nano silicon through a vapor deposition method, coating the surface of the nano silicon with a solid electrolyte through a liquid phase method, and carbonizing to obtain the solid electrolyte coated silicon-carbon composite material. The obtained material has the characteristics of excellent fast charging performance, high initial efficiency and the like when applied to lithium ion batteries.

The invention relates to the technical field of silica powder surface modification, in particular to a novel silica powder surface modification method and application of a composite material of the novel silica powder surface modification method. Silica powder surface modification comprises the steps that silica powder is subjected to surface chemical modification through a titanate coupling agent, active functional groups are introduced, and the interface bonding force between the silica powder and MXene is enhanced; high-quality preparation of MXene: etching an MAX phase by adopting hydrofluoric acid (HF) or lithium fluoride / hydrochloric acid (LiF / HCl), and obtaining few layers of MXene nanosheets through ultrasonic stripping to ensure high conductivity and large specific surface area; the modified silica powder and MXene dispersion liquid are uniformly mixed, MXene stacking is inhibited, the specific surface area is increased, and the ion transmission efficiency is improved; mXene nanosheets grow on the surface of the silica powder in situ to form a core-shell structure, so that the interface bonding strength and the mechanical property are enhanced; the composite material is applied to the fields of electromagnetic shielding, energy storage, flexible electronics and the like.

The invention provides a nanometer silicon-carbon composite negative electrode pre-lithiation material and a preparation method thereof, a battery and power-related equipment, and relates to the field of batteries. The preparation method comprises the following steps: mixing silicon powder, a lithium source and a plurality of carbon source high polymers, and then carrying out high-temperature self-propagating reaction to obtain the nano silicon-carbon composite negative electrode pre-lithiated material. According to the nanometer silicon-carbon composite negative electrode pre-lithiation material provided by the invention, nanometer composite structure design of silicon is carried out through polymer pyrolysis, nanocrystallization of the silicon is realized, the surface of the silicon can be uniformly coated with graphene and silicon carbide, and finally the silicon of which the surface is uniformly coated with the graphene and the silicon carbide is obtained; the silicon-based negative electrode with the structure greatly inhibits volume expansion of silicon in charging and discharging processes. Through high-temperature self-propagating reaction of a lithium source and a silicon-carbon compound, silicon-carbon compounding and pre-lithiation are realized in one step. In the reaction process, the lithium source rapidly releases active lithium at a high temperature, and is subjected to an in-situ reaction with silicon and a cracked carbon layer to form a uniform pre-lithiation interface.

The invention discloses a preparation method of sphere-like porous carbon and a silicon-carbon composite material. The preparation method comprises the following steps: uniformly mixing a carbohydrate compound, an inorganic pore-forming agent, a fibrous pore-forming agent and a cross-linking agent solution, spray-drying, carbonizing, activating and pore-forming to obtain secondary particle sphere-like porous carbon, and then depositing nano silicon on the obtained material by a silane cracking method to obtain the silicon-carbon composite material. According to the obtained material, fibrous channels and granular channels in porous carbon are utilized, deposition of nanometer silicon and reduction of expansion are facilitated, meanwhile, a secondary particle structure is adopted, the intercalation and deintercalation path of lithium ions in the charging and discharging process is shortened, and the rate capability is improved.

The invention provides a silicon-carbon composite material and a preparation method and application thereof.The silicon-carbon composite material comprises a carbon matrix and nanometer silicon particles, the nanometer silicon particles are located in pores of the carbon matrix, the Raman spectrum of the silicon-carbon composite material meets the condition that IA is larger than or equal to 1.2 IB, IA is the peak intensity of the Raman spectrum of the silicon-carbon composite material at 520 cm <-1 > + / -5 cm <-1 >, and IB is the peak intensity of the Raman spectrum of the silicon-carbon composite material at 520 cm <-1 > + / -5 cm <-1 >. And IB is the peak intensity of the Raman spectrum of the silicon-carbon composite material at 480cm <-1 > + / -5cm <-1 >. According to the silicon-carbon composite material provided by the invention, the gas production rate in the anode slurry preparation process can be reduced, the specific capacity of the silicon-carbon composite material is improved, and the high-temperature cycle performance of a secondary battery is improved.

The present invention discloses a silicon-carbon negative electrode composite material, a preparation method thereof, and an application thereof in lithium-ion batteries. The preparation method comprises: using silicon powder as a raw material to generate silicon vapor in a high-temperature negative pressure environment by physical vapor deposition, and then depositing the silicon vapor on a carbon material substrate in a low-temperature zone under the purge of a carrier gas flow; finally, using hydrocarbon gas as a raw material, a carbon coating layer is formed on the surface of the material by chemical vapor deposition, and finally a silicon-carbon negative electrode composite material is obtained. The silicon-carbon interface inside the silicon-carbon negative electrode composite material is a face-to-face combination connected by Si-C chemical bonds. The strong chemical bond can suppress the volume expansion of silicon during the lithium insertion process, and can also enhance the transfer of electrons / ions at the silicon-carbon interface, effectively enhancing the lithium storage performance of the material as a negative electrode material.