8224results about "Negative electrodes" patented technology

The invention discloses a preparation method of a composite high-entropy hard carbon negative electrode material and a sodium ion battery, and relates to the technical field of electrochemical energy storage materials. Existing doping limit is broken through through'high entropy design ', atomic-scale mixing of five elements and more than five elements is realized, strong structural stability which cannot be realized by traditional binary / ternary doping is achieved, 'molecular anchoring' and'entropy locking 'are completed by combining a pre-assembly technology with stepped carbonization, the problem of pain point of multi-element segregation is solved, and the method is suitable for large-scale industrial production. Sodium storage dynamic and thermodynamic properties of a high-entropy hard carbon precursor and an intermediate are synchronously improved through elaborate combination design of multiple elements and subsequent carbonization process parameter optimization, 'defect-interlayer spacing-pore structure 'triple regulation is realized, and the defect degree of high-entropy hard carbon is reduced through design of a coating process; the prepared composite high-entropy hard carbon negative electrode material shows excellent comprehensive performance in a sodium-ion battery, and especially has obvious advantages in high initial coulombic efficiency, high rate capability and long stability.

Provided in the present application are a battery cell and a preparation method therefor, and a battery device and an electric device. The battery cell comprises a negative electrode sheet, the negative electrode sheet comprising a first layer and a non-metallic layer located on the surface on at least one side of the first layer, wherein the nucleation overpotential of Li on the non-metallic layer is V1, and the nucleation overpotential of Li on the first layer is V2, and V1>V2. The negative electrode sheet in the present application can induce the deposition of lithium metal on the surface of a first layer, mitigate dendrite growth and improve the uniformity of lithium metal deposition, thereby improving the cycling performance of battery cells.

The invention discloses a negative electrode interface modification material, a negative electrode plate, a positive electrode interface functional layer, a positive electrode plate, a solid-state battery and a power utilization device, and relates to the technical field of batteries, the negative electrode interface modification material comprises a first polymer matrix, a reinforcing filler, a conductive agent and a lithium salt, the modulus of the reinforcing filler is greater than 50 GPa. The tensile strength of the negative electrode interface modification material can be improved through the first polymer matrix, breakage of a negative electrode interface modification layer is reduced, interface impedance is reduced, meanwhile, the first polymer matrix can be matched with the expansion coefficient of a silicon-based material, and bulging of a negative electrode plate is reduced. The modulus of the reinforcing filler is greater than 50GPa, so that the modulus of the negative electrode interface modification layer can be improved, the expansion of the silicon-based active material is further inhibited, the conductive agent can relieve the problem that the flexible substrate interface of the copper foil and the negative electrode interface modification layer possibly causes unsmooth electron transmission, and the lithium salt can improve the ion conduction capability and reduce the interface impedance.

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 the technical field of sodium-ion batteries, and discloses a super-crosslinked asphalt-based hard carbon material, a preparation method and application thereof, and a sodium-ion battery. Asphalt is subjected to super-crosslinking by adopting a mechanochemical method, and the asphalt, a crosslinking agent and a catalyst realize fracture and recombination of chemical bonds under the action of mechanical shearing force of grinding balls, so that the super-crosslinked asphalt-based hard carbon material is obtained. According to the present invention, the asphalt is subjected to segmented ball milling and super-crosslinking, and then carbonization sintering is performed, such that the asphalt cannot be subjected to molecular rearrangement so as to finally form the hard carbon material with the more suitable microporous structure and the more suitable interlayer spacing, such that the negative electrode ion embedding requirement of the sodium ion battery is met, the excellent sodium storage performance is represented, and the capacity and the first coulombic efficiency of the assembled battery are improved; the performance improvement of the sodium ion battery is integrally promoted. The method is low in energy consumption, short in time consumption, simple in parameter control and suitable for large-scale application and popularization.

The application discloses a high-energy-density lithium ion battery, which comprises a positive electrode sheet and a negative electrode sheet, the positive electrode sheet comprises a positive electrode active material, the positive electrode active material comprises a lithium iron phosphate material and a lithium-rich material, the mass ratio of the lithium-rich material in the positive electrode active material is 0.2%-8%, and the chemical formula of the lithium iron phosphate material is Li 1+x Fe 1‑ y M y (PO4) 1+z , 0<=x<0.1, 0<=y<0.01, 0<=z<0.04, M comprises at least one of Ti, V, Zr, Nb, Mg, Mo, W and Al, the lithium-rich material comprises at least one of LFO and LNO, the chemical formula of the LFO is Li 5+a Fe 1‑b Z b O 4+c , 0<=a<0.5, 0<=b<0.01, 0<=c<0.03, Z comprises at least one of Ti, V, Zr, Nb, Mg, Mo, W and Al, and the chemical formula of the LNO is Li 2+d Ni 1‑ e Y e O 2+f , -0.5<=d<=0.5, e>=0, -0.5<=f<=0.5, Y comprises at least one of Ti, V, Al, Mg, Mn and Fe, and the negative electrode active material comprises a silicon negative electrode material, the mass ratio of the silicon negative electrode material in the negative electrode active material is 1%-50%. The application has the advantages of improving the energy density, rate performance and cycle performance of the lithium battery.

The invention provides a fast-charging type solid-state lithium battery alloy negative electrode material, a preparation method and a solid-state lithium battery, and relates to the technical field of lithium batteries. The alloy negative electrode material comprises the following element components in percentage by mass: 30-38% of indium In, 30-35% of tin Sn, 28-35% of bismuth Bi and 0-1.5% of doping elements, crystal phases formed by the alloy negative electrode material of the fast-charging type solid-state lithium battery at least comprise two crystal phases, namely InSn4 and InBi. The alloy negative electrode material has relatively high surface capacity, lithium ion conductivity and lithium ion diffusion coefficient, lithium dendrites do not grow on a negative electrode when a solid-state lithium battery assembled by the alloy negative electrode material is charged and discharged under high current density, and the battery is high in energy density and long in cycle life.

The invention discloses a high-initial-efficiency fast-charge graphite composite material and a preparation method thereof, the composite material is of a core-shell structure, the core is graphite, and the shell is lithium sulfonate / lithium molybdate and an amorphous carbon coating layer thereof; the mass ratio of the shell is 5-15 wt% according to the mass ratio of the composite material being 100%. The preparation method comprises the following steps: adding a molybdenum compound into a solvent to prepare a solution, adding graphite oxide, an inorganic lithium salt and a carbon nanotube conductive solution, reacting for 2-12 hours at the temperature of 50-120 DEG C, filtering, carbonizing filter residues to obtain a lithium molybdate conductive agent coated graphite material, and depositing a lithium sulfonate derivative on the surface of the lithium molybdate conductive agent coated graphite material by an atomization method to obtain the lithium molybdate conductive agent coated graphite material. The electron and ion conductivity of the material can be improved, and the rate and the first efficiency of the material can be improved.

The invention provides an asphalt-based hard carbon negative electrode material as well as a preparation method and application thereof, belongs to the technical field of battery materials, and is used for solving the technical problems that a template is non-uniformly distributed in a carbon source and the size is difficult to control in hard carbon preparation. The preparation method of the asphalt-based hard carbon negative electrode material comprises the following steps: mixing asphalt and organic zinc salt, and then carrying out heat treatment to obtain high-softening-point asphalt; and pre-oxidizing and carbonizing the high-softening-point asphalt to obtain the asphalt-based hard carbon negative electrode material. Organic zinc salt and asphalt form a metal template in situ at a high temperature, the metal template can be uniformly distributed in the asphalt, meanwhile, the particle size of the template is controlled through process change, and the prepared asphalt-based hard carbon negative electrode material has high reversible specific capacity, high initial coulombic efficiency and good rate capability.

A method for manufacturing an anode electrode includes rolling a first aluminum foil layer; annealing the first aluminum foil layer to create a first annealed aluminum foil layer; mechanically bonding a first lithium metal foil layer between an anode current collector and the first annealed aluminum foil layer; and aging the anode electrode to prelithiate the first annealed aluminum foil layer.

A solid-state battery, preferably a pouch cell, includes a cathode including cathode active material comprising Li ions, graphene, and optionally a binder; an electrolyte; and an anode, preferably a lithium anode, wherein said electrolyte is positioned in between said cathode and said anode.

The present application relates to a hybrid membrane for an electrochemical device, the hybrid membrane comprising: a membrane layer comprising: a modified metal-organic framework (MOF) material wherein the modified MOF material is a MOF material modified with one or more of a lithium salt, a carboxylic acid, or an amino acid, and a binder material, the adhesive layer is used for adhering the modified MOF material to the porous supporting layer so as to form a film layer on the porous supporting layer; and the porous support layer is used for providing mechanical support for the membrane layer. The present application also relates to a method for preparing the hybrid membrane, an electrochemical device comprising the hybrid membrane and the use of the hybrid membrane for inhibiting Lewis acid by-products in an electrochemical device.

The invention discloses a lithium battery negative electrode material coating and carbonization continuous device, and relates to the technical field of lithium battery preparation, the lithium battery negative electrode material coating and carbonization continuous device comprises a feeding mechanism used for continuously receiving a negative electrode material, a coating mechanism arranged at the bottom of the feeding mechanism and used for atomizing a coating liquid and mixing the coating liquid with the negative electrode material, and a carbonization furnace arranged at the bottom of the coating mechanism, the carbonization furnace is used for continuously carbonizing a negative electrode material, a cooling mechanism is arranged at the bottom of the carbonization furnace, the cooling mechanism is used for continuously cooling the carbonized negative electrode material, and a linkage driving mechanism is arranged at the joint of the coating mechanism, the carbonization furnace and the cooling mechanism; the linkage driving mechanism not only provides power for the carbonization furnace and the cooling mechanism, but also provides power for input of nitrogen, so that the coating mechanism, the carbonization furnace and the cooling mechanism can complete continuous coating and carbonization treatment of the negative electrode material only by one group of drives, and the cost of continuous coating and carbonization treatment of the negative electrode material is greatly reduced.

The invention discloses a preparation method and application of a Si / C composite negative electrode material based on CVD rotary kiln gradient deposition coating, and belongs to the field of silicon-carbon negative electrode materials. The method comprises the following steps: filling porous carbon into a CVD rotary kiln, heating under the protection of inert gas, introducing gradient-changing silane and carbon source gas, depositing and coating step by step, dynamically depositing at a set temperature field and a set rotating speed to form a silicon deposition and carbon coating layer with a gradient structure, and cooling to obtain a product. The porous carbon is resin-based or biomass-based porous carbon. The method realizes uniform dispersion of silane and carbon coating, improves material uniformity and interface stability, reduces a specific surface area to reduce side reactions, improves electrochemical performance and cycle stability, and has a large-scale production prospect.

The invention relates to the technical field of lead-acid batteries, and particularly discloses a graphene-based composite material as well as a preparation method and application thereof. The graphene-based composite material comprises a graphene-CNTs three-dimensional composite skeleton, and tin dioxide and titanium dioxide which are loaded on the graphene-CNTs three-dimensional composite skeleton. In the material provided by the invention, the graphene-CNTs three-dimensional composite skeleton has excellent conductivity and mechanical strength, so that the resistivity of a negative plate is remarkably reduced, structural support is provided, and the binding force of lead powder and a negative electrode metal plate grid is enhanced, thereby reducing the falling of active substances and improving the cycling stability of the battery; meanwhile, tin dioxide and titanium dioxide are introduced into the graphene-based composite material and form a multi-stage synergistic system with the graphene-CNTs three-dimensional composite framework, so that the problems that the negative electrode of the lead-acid battery is easy to separate hydrogen, the conductivity is insufficient and active substances fall off can be effectively solved, and the cycle performance of the battery is remarkably improved.

The invention discloses a high-performance sodium ion battery negative electrode ZnS / CoS (at) C composite material and a preparation method thereof, the material preparation method has the characteristics of definite control parameter, easy purity control, simple operation, good process repeatability and the like, and the prepared sodium ion secondary battery negative electrode material has excellent sodium ion intercalation and deintercalation capability and can be used for preparing a sodium ion secondary battery negative electrode material. The specific capacity, the cycling stability, the coulombic efficiency and the rate capability of the sodium ion secondary battery can be effectively improved, the requirements of different conditions can be met, and the application prospect is wide.

The invention discloses a negative electrode active material and a preparation method thereof, a negative electrode pole piece and a secondary battery, the negative electrode active material provided by the invention comprises a silicon-carbon composite material and an aluminum oxide layer coated on the surface of the silicon-carbon composite material, and the silicon-carbon composite material is a composite material of nitrogen-fluorine co-doped porous carbon and nano silicon particles. By optimizing and regulating the porosity and pore size distribution of the porous carbon, the ion transmission kinetics and the structural stability are improved, and the problems of poor rate capability, short cycle life and the like caused by single pore size of the traditional porous carbon are solved. By adopting the nitrogen and fluorine co-doped porous carbon skeleton, the conductivity of the electrode material is enhanced, and the cycling stability of the battery is improved. The nano silicon component uniformly deposited through a chemical vapor phase method provides high specific capacity, the aluminum oxide coating layer can effectively inhibit the decomposition reaction of the solid electrolyte, and the long-term stability and cycle performance of the electrode structure are jointly guaranteed through the dual effects.

The application relates to a cylindrical battery monomer, a battery and a power utilization device. The cylindrical battery monomer comprises electrolyte, an electrode assembly and a shell. The shell contains the electrolyte and the electrode assembly. The electrolyte comprises an electrolyte salt, and the electrolyte salt comprises a hexafluorophosphate. The shell comprises a shell body and a film layer. The film layer is arranged on at least a surface of the shell body facing the electrode assembly. The base element of the film layer is a nickel element. The use reliability and the cycle performance of the cylindrical battery monomer in the embodiment can be improved.

The invention provides a silicon-based material and a preparation method thereof, a negative pole piece and a solid-state battery. The silicon-based material comprises an inner core and a surface coating layer, the inner core comprises a silicon-based negative electrode material, the surface coating layer is a carbon fluoride layer, the carbon fluoride layer internally comprises Li-M, LiF and LiX, M represents a metal element and is selected from at least one of Ag, Mg, Zn and Al, and X represents a non-metal element and is selected from at least one of N, S and P. The silicon-based negative electrode material is used as a core, the surface of the silicon-based negative electrode material is coated with the carbon fluoride layer, and the Li-M alloy / LiF / LiX composite lithium compound is introduced into the carbon fluoride layer, so that triple effects of ion-electron double-conduction network construction, interface chemical stabilization and mechanical buffer enhancement are achieved; and the chemical stability of an interface between the silicon negative electrode and sulfide solid electrolyte is improved while the rate capability of the negative electrode is improved and the expansion and shrinkage of the silicon negative electrode are relieved, and the cycling stability is improved.

The utility model provides a battery negative pole piece and battery, battery negative pole piece includes current collector and active layer, active layer is coated on current collector at least one side surface, on the active layer is equipped with a plurality of groove structure along the length direction of current collector, groove structure extends along the width direction of current collector, and the groove structure is equipped with the groove structure. The active layer is divided into a plurality of areas by the plurality of groove structures along the length direction of the current collector, and each area is provided with a plurality of hole structures. According to the battery negative plate, the hole structures and the groove structures which are sequentially and alternately arranged in the length direction of the current collector are adopted, the liquid injection time of the battery is shortened, meanwhile, the liquid retention amount of electrolyte is increased, the wettability of the electrode is improved, the cycle life is prolonged, the service life of the battery is prolonged, and the performance stability of the battery is improved; and the problem that the battery performance is influenced due to poor wettability of the battery negative plate in the prior art is solved.

The invention discloses a secondary battery and an electric device, and belongs to the technical field of secondary batteries. The secondary battery comprises a positive electrode plate, a negative electrode plate and an electrolyte, the positive electrode plate comprises a positive electrode material layer, the positive electrode material layer comprises a positive electrode material, the positive electrode material comprises lithium iron phosphate, the electrolyte comprises a cyclic sulfate compound, the cyclic sulfate compound comprises an electron donating group, and the cyclic sulfate compound comprises an electron donating group. The negative electrode plate comprises a negative electrode material layer, and when the secondary battery is charged to a full charge state, the negative electrode material layer comprises an iron element and LiC6. By regulating and controlling the mass percentage content a% of electron donating groups in the electrolyte, the mass percentage content b% of LiC6 in the negative electrode material layer and the mass content cppm of the iron element in the negative electrode material layer, b / (10a1 / 2 + c) is within a suitable range, active lithium is effectively compensated, and side reactions between the electrolyte and the positive electrode and the negative electrode can be reduced, so that the cycle life and the safety of the battery are both considered.

The invention relates to the technical field of lithium ion batteries, in particular to a preparation method of a lithium negative electrode with an ion / electron mixed conductor framework and application of the lithium negative electrode in the lithium ion battery. In order to solve the problems of lithium dendrite growth, volume expansion, corrosion and the like of the existing lithium negative electrode material in the battery cycle process, the invention provides an innovative solution that a double-fiber network skeleton consisting of a LiB compound and VGCF is constructed through a mechanical rolling method and a processing regulation and control process so as to enhance the electrode structure stability and inhibit the generation of lithium dendrites. The rate efficiency, the cycle life and the mechanical property of the prepared lithium negative electrode material are evaluated through a symmetric battery test, microstructure and electrochemical property analysis is carried out through TEM, SEM, XRD and other means, and the lithium negative electrode material has excellent comprehensive mechanical property, can inhibit volume expansion, simplifies the processing flow, and is suitable for large-scale production. And the method is suitable for commercial production of new energy batteries. By implementing the invention, the development of a lithium ion battery technology is expected to be promoted, and the requirements of modern society on an efficient and safe energy storage system are met.

The invention discloses a high-entropy oxide composite negative electrode material as well as a preparation method and application thereof, and relates to the technical field of all-solid-state lithium battery negative electrode materials, and the high-entropy oxide composite negative electrode material comprises a metal element and an oxygen element, the high-entropy oxide composite negative electrode material comprises a metal element and an oxygen element, wherein the metal elements are at least five of a chromium element, an iron element, a nickel element, a manganese element, a molybdenum element, a copper element and a cerium element; the molar ratio of the metal element to the oxygen element is 3: 4; the high-entropy oxide composite negative electrode material is of a spinel structure. According to the prepared high-entropy oxide composite negative electrode material, the problems that a traditional negative electrode material is unstable in structure, poor in interface contact and short in cycle life are solved, the electrochemical performance is improved, and an all-solid-state lithium battery prepared from the high-entropy oxide composite negative electrode material shows high reversible specific capacity and excellent cycle stability.

The application belongs to the technical field of batteries, and particularly relates to a silicon-carbon negative electrode material and a preparation method and application thereof. The method comprises the following steps: preparing a porous carbon fiber membrane loaded with a metal catalyst; preparing a dispersion solution of a nano-silicon-based material, and distributing the nano-silicon-based material into the porous carbon fiber membrane to obtain a composite porous carbon fiber membrane; and performing thermal chemical vapor deposition on the composite porous carbon fiber membrane in an inert atmosphere containing a carbon source, growing carbon nanofibers and vertical graphene on the surface of the composite porous carbon fiber membrane, and obtaining a silicon-carbon negative electrode material. Through a synthesis route of thermal chemical vapor deposition (T-CVD), the synthesis process is optimized, and a multi-level three-dimensional network structure of carbon nanofibers and vertical graphene is constructed to enhance the electrical conductivity of the silicon-carbon negative electrode material, accelerate carrier transmission, improve the interface contact performance between the silicon-based material and the carbon material, improve the loading capacity of the nano-silicon-based material, inhibit the volume expansion of the nano-silicon-based material, and improve the structure and cycle stability of the nano-silicon-based material.

The invention provides an additive composition, an electrolyte thereof and a battery. The additive composition comprises a first additive and a second additive, the first additive comprises a compound with a structure as shown in a formula 1, and the second additive comprises a silane additive. When the additive composition provided by the invention is applied to the electrolyte, the cycle performance and the high-temperature performance of the battery can be improved.

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.

Silicon-carbon composites obtainable by a process comprising the following steps: Step 1: Provision of one or more porous carbon particles, wherein the porous carbon particles (i) covalent organic framework compounds (COFs) are, (ii) a mean electrical particle resistance of at least 0.5 MΩ, (iii) a reversible delthiation capacity β of not more than 100 mAh / g and (iv) exhibit a mass loss of no more than 10 wt.% up to 380°C, Step 2: Thermal deposition of silicon from one or more gaseous silicon precursor(s) in the pores and / or on the surface of the porous carbon particles and, if applicable, Step 3: Deposition of additional carbon in the pores and / or on the outer surface of the silicon-carbon composites if the silicon-carbon composites after Step 2 have a specific surface area above 50 m²2 / g, wherein the silicon-carbon composites after step 2 and, if applicable, step 3 a) a specific surface area of ​​at most 50 m² 2 / g and b) have an average electrical particle resistance of at least 0.5 MΩ. Furthermore, a method for producing the silicon-carbon composites according to the invention, their use as active materials in anodes for lithium-ion batteries, anodes containing these silicon-carbon composites, and lithium-ion batteries comprising anodes containing these silicon-carbon composites are the subject of the present invention.

The invention belongs to the technical field of sodium ion battery negative electrode material preparation, and particularly relates to an asphalt-based hard carbon material and a preparation method and application thereof, a negative electrode material and a preparation method thereof, and a sodium ion battery. In order to realize controllable preparation of high-value conversion, highly disordered and low-cost hard carbon of coal pitch, asphalt is used as a precursor material, modified asphalt is synthesized under the action of a solvent, a cross-linking agent and a catalyst, the hard carbon material is prepared through carbonization, and the hard carbon material is large in interlayer spacing and high in disordered degree and is accompanied with defects and closed pores, so that the high-value conversion, highly disordered and low-cost hard carbon is prepared. The preparation method is beneficial to reversible storage of sodium ions and improvement of the electrochemical performance of the sodium-ion battery, so that the sodium-ion battery is fully mixed with a conductive agent, an adhesive and deionized water to prepare slurry, the slurry is uniformly coated on a copper foil in a blade coating manner and is subjected to vacuum drying to prepare a negative electrode material, and the negative electrode material is matched with a corresponding counter electrode, electrolyte and a diaphragm to assemble the battery. The battery is low in cost, high in safety performance, relatively long in cycle life, high in rate capability and good in environmental sustainability.

The invention belongs to the field of batteries, and particularly relates to a lithium supplement negative plate, a preparation method thereof and a battery. The lithium supplementing negative plate comprises a negative current collector and negative active material layers arranged on two sides of the negative current collector; the negative active material layer comprises two lithium supplementing layers and an active material layer arranged between the lithium supplementing layers; the lithium supplementing layer comprises carbon aerogel, and a lithium supplementing agent and a conductive agent which are dispersed in the carbon aerogel. A lithium supplement agent and a conductive agent are dispersed in carbon aerogel, and the lithium supplement agent and the conductive agent are uniformly dispersed in holes of the carbon aerogel by virtue of a three-dimensional network structure of the carbon aerogel; the high adsorbability of the carbon aerogel is beneficial to the tight bonding of the active substance layer and the negative electrode current collector on the two sides of the carbon aerogel layer, so that the stripping force of the active substance is improved; the contact area of the second lithium supplementing layer on the outer side of the active material layer and the electrolyte is large, and the porous structure can improve the electrolyte retention coefficient of the battery; and the lithium supplementing layers are coated on two sides of the active material layer, so that expansion of the silicon negative electrode in the circulation process can be inhibited to a certain extent.

The embodiment of the invention relates to a silicon-carbon composite negative electrode material and a preparation method and application thereof, and the structure of the silicon-carbon composite negative electrode material comprises an inner core and a shell; the inner core is at least one spherical silicon carbon primary particle; the particle size Dv50d1 of the spherical silicon-carbon primary particles is 6-10 [mu] m, and the sphericity psi 1 is greater than or equal to 0.9; the outer surface of the inner core is coated with the shell, and the shell is a carbon coating layer; the particle size Dv50d2 of the silicon-carbon composite negative electrode material is 10-50 [mu] m, d2 / d1 is 1.5-5, the sphericity psi 2 is greater than or equal to 0.6 and less than or equal to 0.95, and psi 1 / psi 2 is 1-1.5. According to the silicon-carbon composite negative electrode material provided by the embodiment of the invention, the inner core is spherical, so that the low expansion rate and the stress dispersion capability of the silicon-carbon composite negative electrode material are ensured. Due to the irregular morphology of the shell, stable contact with electrolyte and a conductive agent can be improved, and the material has good cycle performance.