671 results about "Carbon particle" patented technology

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 invention provides a lithium supplement agent. The lithium supplement agent comprises lithium oxalate particles, conductive carbon particles and additive particles, the conductive carbon particles comprise at least one of carbon black, carbon nanotubes, graphene and ketjen black; the additive particles comprise at least one of MnO2, NiO, Co3O4, TiO2, Fe3O4, MnC, TiC, Mo2C and MoO3, and the additive particles comprise at least one of MnO2, NiO, Co3O4, TiO2, Fe3O4, MnC, TiC, Mo2C and MoO3. According to the lithium supplementing agent disclosed by the invention, by limiting the structure and components of the lithium oxalate lithium supplementing agent, the carbon material is respectively coated in the lithium oxalate and the additive to form a good conductive network, and finally a composite material of the lithium oxalate, the carbon material and the additive is formed, so that the decomposition voltage can be sufficiently reduced; the lithium supplement effect of the lithium oxalate can be exerted to the maximum extent.

The invention provides a system and method for detecting free carbon particles in transformer oil based on a microelectrode array, and the system comprises a sampling module which comprises an oil inlet pipeline and a filtering device, an oil sample is conveyed to a microelectrode array sensor module from a transformer oil tank through the oil inlet pipeline, and the filtering device is located in the oil inlet pipeline; a filter membrane is arranged in the filter device to remove impurities in the oil sample; the microelectrode array sensor module comprises a microelectrode array sensor, the microelectrode array sensor is nanoelectrodes arranged on a silicon substrate, the surface of the microelectrode array sensor is coated with graphene oxide to adsorb free carbon particles in an oil sample, and when the free carbon particles are adsorbed to the surface of the microelectrode array sensor, an adsorption signal is generated; and the signal processing unit is used for extracting the characteristic frequency and intensity of the vibration of the carbon particles in the adsorption signal, and classifying the carbon particles according to the characteristic frequency and intensity of the carbon particles. The device is compact in structure, the maintenance cost is reduced, and the operation process is simplified.

Document (100) with a security feature, comprising: a first substrate layer (103) having a first substrate layer region (105), wherein the substrate layer region (105) is impregnated with a black fluid over the entire thickness of the first substrate layer (103), the black fluid having carbon particles; a second substrate layer (107) with a second substrate layer region (109), wherein the second substrate layer (107) is arranged above the first substrate layer (103), the second substrate layer region (109) having a light reflection characteristic which differs from a light reflection characteristic of the first substrate layer region (105), wherein the first substrate layer region (105) and the second substrate layer region (109) form a composite security feature.

The invention relates to the technical field of heavy oil product treatment, in particular to a method and device for co-production of a carbon material through molten salt pyrolysis of a liquid oil product, and the method comprises the following steps: the liquid heavy oil product is put into an electric heating molten salt reactor through a continuous feeding system, and the molten salt reactor is filled with a molten alkaline molten salt medium; carrying out catalytic pyrolysis reaction on the oil product in a liquid phase environment of the molten salt medium, wherein the oil product stays in the molten salt for 5-10 seconds; the liquid oil product is uniformly cracked in the liquid phase of the molten salt to generate low-carbon hydrocarbon gas, hydrogen and dispersed fine carbon particles, and the carbon particles suspend on the surface under the buoyancy action of the molten salt and are not deposited and gathered; suspended carbon particles are collected from the surface of the fused salt in real time through a mechanical push rod continuous collection system; according to the method, continuous and stable pyrolysis of the heavy oil product and efficient and continuous separation of the product can be realized in the liquid-phase molten salt environment, the production efficiency is improved, and the stability of the product quality is ensured.

An electrode composite material and a method of making same are disclosed. A mixture that includes lithium sulfide (Li2S) particles containing a Li2S compound, carbon particles, and halogenated lithium phosphorous sulfide (LPS-X) particles containing an LPS-X (X is F, Cl, Br, and / or I) compound are provided. The LPS-X particles have crystallinity which can be confirmed with XRD of the LPS-X particles or the mixture showing XRD peaks indicative of crystalline LPS-X. The mixture does not include lithium phosphorous sulfide (LPS) particles made of an LPS compound. The mixture is ball-milled to provide a ball-milled composite material. At least part of the LPS-X compound contained in at least part of the LPS-X particles is converted to the LPS compound. XRD of the ball-milled composite material shows none of the XRD peaks indicative of crystalline LPS-X.

The invention relates to the technical field of battery negative electrode materials, in particular to irregular spherical porous carbon and a preparation method and application thereof, and a silicon-carbon composite material and a preparation method and application thereof. The liquid phenolic resin is emulsified, compounded, cross-linked and cured under the condition of an oil-soluble and water-soluble compound emulsifier, meanwhile, the shape of the obtained resin is changed in an ultrasonic-assisted mode under the combined action of ultrasonic disturbance and different interfacial tensions, spherical resin is adjusted into irregular spherical resin, and the spherical resin is prepared into the irregular spherical resin. And performing pyrolysis and gas activation to obtain the irregular porous spherical carbon. Compared with spherical carbon, the irregular spherical carbon prepared by the invention has the advantages that on the premise of keeping the strength of the spherical carbon, the irregular spherical carbon can increase the contact area between carbon particles and a binder, and the carbon particles and the binder are not easy to separate, so that the cycling stability of a battery (especially a lithium ion battery) is improved.

The invention belongs to the technical field of SiC crystal growth, and particularly relates to a thermal field component for SiC crystal growth and a preparation method of the thermal field component. The thermal field component comprises a thermal field component body, and the thermal field component body is made of a porous tantalum carbide material. The thermal field component can efficiently filter carbon particles, has corrosion resistance and long service life, and can remarkably reduce the production cost.

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 belongs to the technical field of batteries, and particularly relates to a preparation method of coating slurry, a silver-carbon negative electrode plate, a preparation method of the silver-carbon negative electrode plate and a solid-state battery. Compared with the prior art, by controlling the agglomeration degree of the silver material in the negative electrode active coating, silver and carbon particles can be uniformly dispersed, and on the basis of avoiding the generation of lithium dendrites, attachment sites and spaces of the silver particles on the carbon particles are increased, so that the safety performance and the electrical performance of the battery are improved.

A method comprising obtaining a bodily fluid from a subject; contacting the bodily fluid with an adsorbent material comprising a synthetic carbon particle (SCP) to produce a first filtrate having a level of disease mediators (y); contacting the first filtrate with an adsorbent material comprising the SCP and an anion exchange resin where the ratio of SCP to anion exchange resin is in a range from about 0.1:100 to 100:0.1 to produce a second filtrate; contacting the second filtrate with an adsorbent material comprising the SCP and a cation exchange resin where the ratio of SCP to cation exchange resin is in a range from about 0.1:100 to 100:0.1 to produce a third filtrate.

The invention discloses a preparation method of a coconut shell carbon-based loaded organic photovoltaic material decarbamazepine photocatalyst. The method comprises the following steps: A, cleaning coconut shells, and drying until the coconut shells are completely dried; b, crushing the completely dried coconut shells with a crusher, and sieving with a 200-mesh sieve to obtain coconut shell powder; c, drying the coconut shell powder, and performing high-temperature pyrolysis on the dried coconut shell powder in a tubular furnace to obtain modified carbon-based material coconut shell carbon particles; d, mixing an organic photovoltaic material and chloroform according to the following weight ratio: 0.01-0.02 g of the organic photovoltaic material and 10-20 ml of chloroform to obtain an organic photocatalyst mixed solution; and E, uniformly coating modified carbon-based material coconut shell carbon particles with the organic photocatalyst mixed solution obtained in the step D, and drying at 60 DEG C for 24 hours to obtain the coconut shell carbon-based loaded organic photocatalyst. And F, adding a reinforcing agent polyethylene glycol solution into the organic photocatalyst mixed solution in the step E, uniformly mixing for 0.5 h, and drying at 60 DEG C for 12 h to obtain the coconut shell carbon-based loaded organic photovoltaic material carbamazepine photocatalyst. The photocatalyst obtained by the method disclosed by the invention can be used for efficiently and quickly removing carbamazepine and can be repeatedly utilized, the problems of a photocatalyst loading process and cyclic utilization are solved, and a real green, environment-friendly and pollution-free treatment method is provided for removing carbamazepine.

The invention belongs to the technical field of lithium ion battery negative electrode material preparation, and relates to a method for preparing a silicon alloy negative electrode based on three-dimensional spin control magnetron co-sputtering, which comprises the following steps: 1, substrate preparation: selecting carbon particles as a negative electrode material substrate; 2, particle three-dimensional spinning suspension: placing the carbon particles in a three-dimensional spinning suspension device, and continuously rolling and rotating in a plurality of space directions in a high vacuum environment; 3, sputtering target material configuration, wherein a silicon target and at least one alloy metal target are arranged in a magnetron co-sputtering cavity; 4, co-sputtering deposition: performing magnetron co-sputtering on the rotating carbon particles in a high-purity argon working atmosphere, and dynamically adjusting the input power of each target to enable a deposition coating to form a gradient composite alloy structure from a rich metal buffer layer to a high-silicon content region to obtain a composite powder material; the high silicon content is guaranteed, meanwhile, a buffer alloy phase and an interface bonding layer are introduced, and the problems of volume expansion and interface stripping in the circulation process are effectively solved.

The invention provides a negative-electrode-free sodium ion battery current collector, application thereof and a negative-electrode-free sodium ion battery, and relates to the technical field of batteries. The negative-electrode-free sodium ion battery current collector provided by the invention comprises a base material and a coating coated on the surface of the base material, the coating comprises porous nitrogen-doped carbon particles and a binder; the porous nitrogen-doped carbon particles are loaded with fluorine-containing sodium salt and a metal catalyst, and the surfaces of the porous nitrogen-doped carbon particles are coated with polymers. According to the current collector, in-situ construction and dynamic repair of NaF-rich SEI are promoted through the core-shell structure design, long-term, uniform and stable deposition of sodium ions on the current collector can be achieved, the coulombic efficiency of a negative-electrode-free sodium battery is improved, and the cycle life of the negative-electrode-free sodium battery is prolonged.

The invention relates to the technical field of batteries, in particular to a negative plate and a lithium ion secondary battery comprising the negative plate. Comprising a negative electrode current collector and a negative electrode active layer, the negative electrode active layer comprises a first active layer, the first active layer comprises a silicon-carbon material, and the silicon-carbon material comprises first silicon-carbon particles and second silicon-carbon particles; the sphericity degree of the first silicon-carbon particles is 0.8-1, the average particle size of the first silicon-carbon particles is 5-20 [mu] m, and the mass content of silicon is 30-60%; the second silicon carbon particles comprise secondary particles formed by a plurality of primary spherical particles; the degree of sphericity of the primary spherical particles is 0.8-1, and the average particle size of the primary spherical particles is 100 nm to 2.5 microns; the average particle size of the second silicon-carbon particles is 5-36 [mu] m, the sphericity is 0.35-0.79, and the mass content of the silicon element is 25-55%. Comprising the negative plate disclosed by the invention has relatively high energy density and also has relatively excellent cycle performance and rate capability.

The application relates to the technical field of lithium / sodium ion battery negative electrode materials, in particular to a phosphorus-based negative electrode material with a solid electrolyte interface and a preparation method and application thereof, the method comprises the following steps: mixing phosphorus powder, a carbon material and a metal fluoride and performing ball milling to obtain a composite negative electrode material; and performing sieving treatment on the composite negative electrode material to obtain the phosphorus-based negative electrode material. According to the application, the metal fluoride is doped to in-situ construct a solid electrolyte interface with high strength and high lithium ion / electron transmission, so that the cycle stability and the rate performance of the battery are improved. When the lithium ion battery is discharged, the metal fluoride can in-situ construct a solid electrolyte interface rich in fluorinated lithium with high Young's modulus and lithium-metal alloy with high ion / electron conductivity on the surface of phosphorus-carbon particles prior to phosphorus-carbon lithium intercalation, the solid electrolyte interface can enhance the strength of the solid electrolyte interface by means of the fluorinated lithium with high Young's modulus, so as to inhibit the expansion of the phosphorus-carbon negative electrode, and the cycle stability is improved.

The invention discloses a sound barrier made of a tailing material and a preparation method of the sound barrier, and belongs to the technical field of sound barriers. The sound barrier comprises a base material, a functional additive and a self-healing additive, and the base material mainly adopts tailing particles and is compounded with alumina powder, Portland cement and nano-hydroxyapatite; the functional additive is prepared from a polypyrrole-polyaniline compound, silicon dioxide nano aerogel, nano molybdenum disulfide particles and polyacrylate coated paraffin microcapsules; the self-healing additive is prepared from polyurethane coated epoxy resin microcapsules, polyurethane coated amine curing agent microcapsules, CaCO3 microcrystals, nano montmorillonite particles and nano nickel coated carbon particles. Resource utilization of the tailings is achieved, and the mechanical property, the sound absorption and insulation performance, the self-healing performance and the weather resistance of the sound barrier are remarkably improved.

The invention relates to the technical field of batteries, in particular to a lithium ion secondary battery. Comprising an electrode assembly and electrolyte, and the electrode assembly comprises a positive plate, a diaphragm and a negative plate which are stacked and wound; the charging cut-off voltage of the lithium ion secondary battery is greater than or equal to 4.5 V; the positive plate comprises lithium cobalt oxide, the lithium cobalt oxide contains an element aluminum, and the mass content of the element aluminum in the lithium cobalt oxide accounts for 7000 ppm to 12000 ppm; the negative plate comprises a silicon-carbon material, and the silicon-carbon material comprises first silicon-carbon particles and second silicon-carbon particles; the sphericity degree of the first silicon-carbon particles is 0.8-1, the average particle size of the first silicon-carbon particles is 8-20 [mu] m, and the mass content of silicon is 30-60%; the sphericity degree of the second silicon-carbon particles is 0.8-1, the average particle size is D, and 1 [mu] m is smaller than or equal to Dlt; the mass content of the silicon element accounts for 20%-45%; the mass content ratio of the silicon element in the first silicon-carbon particles is greater than the mass content ratio of the silicon element in the second silicon-carbon particles. The lithium ion secondary battery can have both high energy density and high-temperature cycle stability.

The invention discloses a 2.5 D woven ceramic-based composite material based on a C / C composite material and a preparation method of the 2.5 D woven ceramic-based composite material, and belongs to the technical field of ceramic-based composite material preparation. According to the method, C / C waste scraps are introduced into a low-density 2.5 D woven composite material, resin carbon serves as a binder to form a three-dimensional network structure, a carbon skeleton of the formed three-dimensional network structure contains carbon fibers and carbon particles, the carbon fibers and the carbon particles are in lap joint to provide more sites for reaction of alloy melt, full reaction of the melt is promoted, the content of residual metal is reduced, and the mechanical property of the composite material is improved. According to the method disclosed by the invention, large-size pores between warp yarns and weft yarns of the 2.5 D woven preform are reduced, meanwhile, the recycling of the waste C / C composite material is realized, the pollution of wastes to the environment is reduced, and the green sustainable development is promoted.

The invention discloses a negative electrode material, a negative electrode plate prepared from the negative electrode material, and a secondary battery, and belongs to the technical field of electrochemical energy storage. And the size of the silicon-carbon particles and the thickness of the coating layer are synchronously regulated and controlled based on the particle size difference of the graphite particles, so that the material not only can realize ideal cycle stability when being applied to the negative electrode material of the secondary battery, but also has excellent floating charge performance.

The invention relates to the technical field of sodium-ion battery negative electrode materials, and discloses a preparation method of a high-performance silicon-carbon negative electrode material, which comprises the following steps: step 1, obtaining a porous silicon-carbon material; step 2, obtaining a porous silicon carbon dispersion liquid with positive charges; step 3, dispersing to obtain a surfactant modified porous silicon carbon material dispersion liquid with positive charges; step 4, obtaining single-layer MXene powder; step 5, obtaining an MXene dispersion liquid; step 6, obtaining a mixed solution; and 7, obtaining the MXene coated silicon carbon negative electrode material for the negative electrode of the lithium ion battery. Porous silicon carbon particles with positive charges are spontaneously inserted between single-layer MXene sheet layers by utilizing simple electrostatic interaction, the problem of volume expansion of silicon can be relieved by a porous silicon carbon structure, MXene has excellent hydrophilicity and electronic conductivity, and meanwhile, the problem of expansion of a silicon material can be effectively improved by MXene with a layered structure; and the cycling stability and the rate capability are enhanced.

The invention provides a silicon negative pole piece, a preparation method thereof and a solid-state battery. The silicon negative electrode piece comprises a negative electrode current collector and silicon negative electrode slurry coated on the surface of the negative electrode current collector, the silicon negative electrode slurry comprises a solid electrolyte, nano silicon, mixed silicon carbon, a conductive agent, a binder and a solvent, the mixed silicon carbon comprises first silicon carbon and second silicon carbon with different particle sizes, the particle size distribution D50 of the solid electrolyte is smaller than the particle size distribution D50 of the first silicon carbon, and the particle size distribution D50 of the first silicon carbon is smaller than the particle size distribution D50 of the second silicon carbon. According to the silicon negative electrode plate provided by the invention, through compounding of silicon carbon with different particle sizes and the solid electrolyte, more expansion space is provided for nanometer silicon, and the technical effect of effectively reducing the expansion rate of the silicon negative electrode plate is achieved.

The invention relates to the technical field of crystal growth, in particular to a crucible device for growth of silicon carbide single crystals with low-carbon wrappage and a growth method, and the crucible device comprises a crucible body, a crucible cover and silicon carbide seed crystals, a porous graphite cylinder used as a first filter is also arranged in the crucible body; the porous graphite cylinder is filled with tantalum particles used as a second filter; a shielding plate ring and a porous graphite plate used as a third filter are arranged above the porous graphite cylinder; a filling cavity used for containing silicon carbide powder is formed between the outer side wall of the porous graphite cylinder and the inner wall of the crucible body. According to the crucible device, gas components generated by sublimation of silicon carbide powder can be filtered through the porous graphite cylinder, the tantalum particles and the porous graphite plate, and carbon particles and other impurity particles in the gas components are filtered and removed; the crucible device solves the problems that silicon carbide single crystals grown by an existing crucible device in the prior art have the defects of carbon wrappage, microtubes, dislocation and the like.

The invention provides a composite silicon-carbon negative electrode material and a preparation method thereof, a negative electrode plate and a battery. The composite silicon-carbon negative electrode material comprises a silicon-carbon composite core, and a gradient pore carbon buffer layer and a dynamic self-healing binder layer which sequentially coat the surface of the silicon-carbon composite core, a branched carbon nanostructure grows in the pore wall of the gradient pore carbon buffer layer, the dynamic self-healing binder layer partially permeates into the pores of the gradient pore carbon buffer layer, the dynamic self-healing binder layer contains dynamic disulfide bonds, and the dynamic self-healing binder layer comprises a composite binder and a conductive high-molecular polymer. According to the invention, the gradient pore buffer layer is arranged on the surface of the silicon-carbon particles, and meanwhile, the self-healing binder containing dynamic disulfide bonds is used for permeation filling, so that three-dimensional cooperative regulation and control of graded dissipation of expansion stress, self-repairing of microcracks and ion / electron dual-path conduction are realized; the three core problems of electrode pulverization caused by volume expansion, interface impedance sharp increase and long circulation capacity attenuation are thoroughly solved.

The invention discloses a micro-fine particle flotation method for electrolytic aluminum anode carbon slag after lithium extraction based on ball milling activation and interface regulation and control. The method comprises the following steps that the electrolytic aluminum anode carbon slag after lithium extraction is pretreated to obtain carbon slag lithium extraction slag; carrying out ball milling activation on the carbon residue lithium extraction residue; the activated ore pulp is subjected to flotation pretreatment and flotation separation; the carbon concentrate obtained through flotation is subjected to alkaline leaching impurity removal, high-grade carbon concentrate is obtained, and meanwhile tailings can be directly used as regenerated electrolyte. According to the method, the surface performance of the carbon particles is enhanced through ball milling activation, the flotation recovery efficiency and selectivity are improved, synergistic efficient recovery of the carbon and the electrolyte is achieved, and the method has the advantages of being simple and convenient in process, high in recovery rate, environmentally friendly and the like. The grade of the obtained carbon concentrate can reach 85.65%, and the fluorine grade in the tailings is ensured, so that the carbon concentrate can be directly recycled as electrolyte or further recycled.

An electrode composite material and a method of making same are disclosed. A mixture that includes lithium sulfide (Li2S) particles containing a Li2S compound, carbon particles, and halogenated lithium phosphorous sulfide (LPS-X) particles containing an LPS-X (X is F, Cl, Br, and / or I) compound are provided. The LPS-X particles have crystallinity which can be confirmed with XRD of the LPS-X particles or the mixture showing XRD peaks indicative of crystalline LPS-X. The mixture does not include lithium phosphorous sulfide (LPS) particles made of an LPS compound. The mixture is ball-milled to provide a ball-milled composite material. At least part of the LPS-X compound contained in at least part of the LPS-X particles is converted to the LPS compound. XRD of the ball-milled composite material shows none of the XRD peaks indicative of crystalline LPS-X.

The invention provides a negative electrode material and a preparation method thereof, a secondary battery and electronic equipment, the negative electrode material comprises silicon carbon particles, the oxygen content of the silicon carbon particles is X%, 3 < = X < = 10, each silicon carbon particle comprises an internal region and a surface region, the surface region refers to a region less than 20nm away from the surface of the silicon carbon particle, and the surface region refers to a region less than 20nm away from the surface of the silicon carbon particle. The internal region refers to the other region except the surface region in the silicon carbon particles, the oxygen content of the internal region is X1%, and 3 < = X1 < = 10. According to the negative electrode material provided by the invention, the specific capacity and the first coulombic efficiency of the negative electrode material can be improved, and the I TC cycle expansion of the secondary battery is reduced.

In general, the present invention relates to a charged sorbent material. In particular, but not exclusively, the present invention relates to a charged adsorbent material comprising a porous carbon material and charged non-carbon particles within the pores of the porous carbon material. The invention also relates to a method of manufacturing a charged adsorbent material and to a method of removing adsorbates from a fluid by contacting the fluid with the charged adsorbent material.

The invention relates to an insulating oil carbon particle intelligent detection method and device based on a microstructure gradient electric field, and the method is characterized in that the method comprises the following steps: installing an electrode array in an oil tank of a transformer through a special support, guaranteeing the full contact of electrodes and insulating oil, and connecting a signal processing unit, a display alarm module and a remote monitoring module; a monitoring period, an alarm threshold value and an alarm level are set through the touch screen, network parameters of the remote monitoring module are configured, and data uploading is ensured; applying a high-frequency alternating-current electric field to the electrode system, collecting an electric field signal in real time, analyzing the electric field signal by using a deep learning algorithm, identifying the type of the carbon particles and calculating the concentration of the carbon particles; when the detected carbon particle concentration exceeds a set threshold value, the system triggers sound-light alarm and sends a short message notification.

The invention provides a negative electrode material and a preparation method thereof, an electrochemical device and an electronic device, the negative electrode material comprises silicon carbon particles, each silicon carbon particle comprises a first region and a second region, and the first region is a region from the surface of the silicon carbon particle to a depth of 100 nm from the surface of the silicon carbon particle; the second region is a region which is 200 nm away from the surface of the silicon carbon particle to 500 nm away from the surface of the silicon carbon particle; the silicon-carbon particles comprise silicon elements and carbon elements; based on the total number of atoms of the silicon element and the carbon element in the first area, the percentage of the number of atoms of the silicon element is A%, and A is larger than or equal to 4.04 and smaller than or equal to 16.89; based on the total number of atoms of the silicon element and the carbon element in the second area, the percentage of the number of atoms of the silicon element is B%, and B is larger than or equal to 15 and smaller than or equal to 20.88. The electrochemical device has good cycle performance and safety performance, and lithium precipitation of the negative electrode can be improved.