720 results about "Lithium ion battery anode" patented technology

The invention relates to the field of batteries, in particular to a preparation method and system of a silicon-carbon material, and the preparation method comprises the following steps: pretreating porous carbon, conveying the pretreated porous carbon to a fluidized bed reactor, sequentially introducing a silicon source gas and a carrier gas for silicon deposition treatment, heating, introducing a carbon source gas, adjusting the flow of the carrier gas for carbon coating treatment, and discharging and cooling to obtain a finished product, meanwhile, reaction tail gas is recycled. The preparation system comprises a gas inlet unit, a fluidized bed reactor unit, a tail gas circulation unit, a feeding preheating unit and a discharging unit. The fluidized bed reactor comprises an outer shell, an up-down stirring device, a heat exchange assembly and an air distribution assembly, and efficient reaction and temperature control can be achieved. The silicon-carbon material prepared by the method has excellent electrochemical performance and is suitable for a lithium ion battery negative electrode material. The unique porous structure and the uniform carbon coating layer effectively improve the conductivity and the structural stability of the material, and meanwhile, the volume expansion effect of silicon in the charging and discharging process is reduced.

The invention discloses a silicon-carbon negative electrode material, a preparation method thereof and a lithium ion battery, and relates to the technical field of lithium ion battery negative electrode materials. The material sequentially comprises a porous silicon core, a transition layer and a shell from inside to outside, the transition layer is a nitrogen-doped SiC / C composite layer, the shell comprises a graphene / carbon nanotube skeleton and MXene quantum dots, the MXene quantum dots are embedded in the graphene / carbon nanotube skeleton, boric acid ester bonds exist between carbon nanotubes and graphene, and the MXene quantum dots are embedded in the graphene / carbon nanotube skeleton. The silicon-carbon negative electrode material is based on dual-network dynamic bonding and stress gradient regulation and control, the cycle performance of the material can be remarkably improved, and the service life of the material can be remarkably prolonged.

The invention belongs to the technical field of lithium ion battery negative electrode materials, and particularly relates to a spinel type metal oxide coated hard carbon composite material based on a lattice matching mechanism, and a gradient doping preparation method of the spinel type metal oxide coated hard carbon composite material can overcome the defects that a hard carbon material is low in initial coulombic efficiency (about 50%), low in lithium ion transmission rate and poor in rate capability. According to the invention, magnesium salt, aluminum salt, copper salt and other metal salts are mixed with hard carbon, a precipitant is added, and a hydrothermal method is combined with a calcination process to obtain the core-shell structure composite material with hard carbon coated with a spinel structure. The technology has the following three obvious advantages: (1) lattice adaptive design of the spar type metal oxide and the hard carbon, (2) molybdenum-copper gradient doping repair of the SEI film, and (3) stable circulation of more than 5000 times at the capacity of 350mAh / g.

The invention provides a negative electrode plate and a lithium ion battery, the negative electrode plate comprises a negative electrode current collector, a first negative electrode active layer and a second negative electrode active layer, the negative electrode current collector comprises a first region and a second region, the first region is arranged on the negative electrode current collector, the second region is located between the edge of the negative electrode current collector and the edge of the first region, the first negative electrode active layer is arranged in the first region, and the second negative electrode active layer is arranged in the second region; the Young's modulus of the second negative electrode active layer is greater than the Young's modulus of the first negative electrode active layer. According to the negative electrode plate provided by the invention, the second negative electrode active layer is arranged in the second region of the negative electrode current collector, the Young modulus of the second negative electrode active layer is greater than that of the first negative electrode active layer, and the relatively large Young modulus can inhibit volume expansion generated by the edge of the negative electrode plate in the charging and discharging process, so that the extension stress in the width direction of the negative electrode plate is reduced; the condition of corner damage caused by excessive extension of the negative plate is improved, so that the safety performance of the lithium ion battery is improved.

The invention belongs to the technical field of lithium battery materials, and particularly relates to a lithium trifluoromethanesulfonate in-situ doped graphdiyne composite material and a preparation method and application thereof. The preparation method of the lithium trifluoromethanesulfonate in-situ doped graphdiyne composite material adopts a one-step in-situ synthesis method, and specifically comprises the following steps: adding hexaacetylene benzene and lithium trifluoromethanesulfonate into a solvent, mixing, adding a catalyst, carrying out a heating reaction, and carrying out post-treatment on the obtained reactant to obtain the lithium trifluoromethanesulfonate in-situ doped graphdiyne composite material. Finally, the lithium trifluoromethanesulfonate in-situ doped graphdiyne composite material is obtained. The preparation method of the lithium trifluoromethanesulfonate in-situ doped graphdiyne composite material provided by the invention is simple in process, the prepared composite material is good in interface stability, and when the composite material is applied to a negative electrode of a lithium ion battery, the electrochemical performance of the battery can be improved, and the service life of the battery can be prolonged.

The invention discloses a lithium ion battery negative electrode material for a start-stop power supply and a preparation method of the lithium ion battery negative electrode material, and belongs to the field of battery materials. The lithium ion battery negative electrode material for the start-stop power supply is formed by compounding artificial graphite secondary particles and hard carbon, the compounding mass ratio of the artificial graphite secondary particles to the hard carbon is (1-10): (10-1); the problems that an existing material is low in rate capability and high in cost are solved.

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 discloses a method for preparing a graded porous structure Si-C composite material based on a double-template method, and belongs to the technical field of lithium ion battery negative electrode materials. The method specifically comprises the following steps: (1) silicon waste pretreatment; (2) preparing a double-template / carbon source precursor mixture; (3) sealing, transferring and charging; (4) carrying out in-situ reduction, carbonization and pore forming; (5) template removal and post-treatment; (6) solvent replacement; and (7) drying. The invention relates to a method for preparing a carbon-coated silicon-based composite material (Si-C) with a hierarchical porous structure by using silicon waste (SSW) generated by diamond wire cutting in the photovoltaic industry as a raw material through an innovative synergistic double-template method. When the material prepared by the method is used for a lithium ion battery negative electrode, the key problems of serious volume expansion and short cycle life of a silicon-based material can be solved, and meanwhile, high-added-value resource utilization of solid waste is realized.

The invention discloses a modified acrylate emulsion adhesive as well as a preparation method and application thereof, and belongs to the technical field of lithium ion batteries. The modified acrylate emulsion adhesive is prepared by adopting a semi-continuous emulsion polymerization method. The water-based adhesive is prepared from the following raw materials in parts by weight: 5-20 parts of water-based polyolefin, 50-200 parts of deionized water, 0.5-4 parts of an emulsifier, 20-50 parts of an acrylate monomer, 1-10 parts of an acrylic monomer, 0.2-1.5 parts of an initiator, 0-50 parts of styrene, 0.1-2 parts of a cross-linking agent and 0.5-15 parts of a neutralizer. The modified acrylate emulsion adhesive is obtained by taking the water-based polyolefin as a core structure of the emulsion and taking the acrylate polymer as a shell structure of the emulsion, and the adhesive has good compatibility with a polyolefin diaphragm and an electrolyte, so that the synergism of a lithium ion battery negative electrode, the electrolyte and the diaphragm is promoted; further, the electrochemical performance of the lithium ion battery is improved.

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 lithium ion battery negative electrode materials, in particular to a silicon-carbon negative electrode material based on spherical-like resin porous carbon and a preparation method thereof.The method comprises the steps that resin and an emulsifier are fully reacted, solid resin microspheres are obtained after treatment, then high-temperature carbonization is conducted, potassium hydroxide activation is conducted after smashing, and the spherical-like resin porous carbon-based silicon-carbon negative electrode material is obtained; and carrying out acid washing to obtain the spheroidic porous carbon. And the silicon-carbon negative electrode material is obtained after vapor deposition, and the material is particularly suitable for a high-energy-density power battery.

The invention relates to the technical field of binders, in particular to a lithium ion battery negative electrode binder and a preparation method thereof, the lithium ion battery negative electrode binder comprises the following raw materials by weight: 15-45 parts of a temperature resistant material, 10-20 parts of a toughening material, 6-10 parts of an anticorrosive filler, 50-150 parts of bisphenol epoxy resin and 1-5 parts of a reducing agent. According to the preparation method, side reactions existing in the preparation process of the lithium ion negative electrode battery are inhibited, the electrochemical stability, interface compatibility and processing performance of the lithium ion battery are improved, the binding force of the negative electrode binding interface of the lithium ion battery can be enhanced, a rigid-flexible interpenetrating network is formed, the fracture toughness of the binding agent is improved, and the service life of the binding agent is prolonged. Through the synergistic effect of fluorination modification and a rigid framework, the three-in-one performance of high adhesion, electrolyte resistance and high temperature resistance is achieved, cerium oxide nanoparticles can be subjected to oxidation reduction, free radicals are eliminated, electrolyte oxygenolysis is inhibited, and the problems that an adhesive is weak in adhesion force and poor in electrolyte corrosion resistance stability are solved.

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 application belongs to the technical field of lithium ion battery adhesives, and particularly relates to a hyperbranched network polyacrylic acid resin special for silicon-carbon negative electrodes, a preparation method and application thereof. The hyperbranched network polyacrylic acid resin special for silicon-carbon negative electrodes comprises, by mass fraction, 3-10 parts of water-based acrylic acid resin, 4-10 parts of monomer A, 2-6 parts of monomer B, 2-6 parts of monomer C, 60-80 parts of solvent, 0.1-0.2 parts of chain extender, 1-8 parts of crosslinking agent and 0.5-1 part of silane coupling agent. The monomer A is an acrylic ester monomer, the monomer B is an acrylamide monomer, the monomer C is at least one selected from an allyl amine monomer and an acrylonitrile monomer, and the chain extender is at least one selected from dodecyl mercaptan and 2-mercaptoethanol. The polyacrylic acid resin has high viscosity and peeling strength, and the prepared lithium ion battery negative electrode material has high discharge specific capacity and cycle performance.

The invention discloses fast charge graphite, a preparation method thereof and a lithium ion battery negative electrode material, and the preparation method comprises the following steps: carrying out acid leaching elution and alkali liquor neutralization on natural graphite fine powder to passivate the surface of the natural graphite fine powder; mixing the passivated graphite fine powder with boric acid and acetic acid, and then carrying out heating reaction to obtain modified graphite fine powder; mixing the modified graphite fine powder with a binder, and granulating to obtain secondary particles; after the secondary particles are subjected to graphitization treatment, the graphitized secondary particles are coated with a carbon source coating agent, and then carbonization treatment is conducted in the inert atmosphere; and carrying out vacuum impregnation on the carbonized secondary particles in a lithium source solution, and drying to obtain the lithium ion battery positive electrode material. The preparation method has the advantages that the interlayer spacing of the natural graphite can be expanded by modifying the natural graphite fine powder, and then the natural graphite is subjected to granulation, graphitization and carbon coating treatment and then is subjected to gradient coating, so that the prepared fast-charging graphite has more excellent dynamic performance.

The invention discloses a negative electrode coating material production method, a negative electrode coating material and a lithium ion battery, and relates to the technical field of lithium battery material preparation, and the negative electrode coating material production method comprises the following steps: carrying out functional modification on a covalent bond of a carbon nanotube to obtain a functional carbon nanotube grafted with a specific functional group; dispersing the composite material in an organic solvent, adding a coating precursor and a dispersion binder to form coating slurry, adding a silicon-based negative electrode matrix, and performing spray drying to obtain a pre-coated composite material; a three-dimensional gradient composite coating structure is formed sequentially through low-temperature dehydration crosslinking, medium-temperature pre-carbonization and catalysis and high-temperature graphitization and densification treatment, an amorphous carbon layer, a functionalized carbon nanotube reinforced composite layer and a highly-graphitized outer surface layer are arranged from inside to outside, the thickness of the material coating layer is 50-200 nm, the volume resistivity is smaller than or equal to 5 * 10 <-3 > omega.cm, the first coulombic efficiency at 0.1 C is larger than or equal to 85%, and the specific surface area of the material coating layer is larger than or equal to 10%. And the capacity retention ratio after 500 cycles is greater than or equal to 80%, so that the material is suitable for high-performance lithium ion battery negative electrodes.

This invention belongs to the field of lithium-ion battery technology, specifically relating to a method for constructing Si@COF-Co materials using porphyrin COF as a conductive nano-protective layer for nano-silicon and its application. The invention first adds a methanol solution of PEI to a methanol solution of nano-silicon, then dries it at high temperature to obtain PEI-modified nano-silicon Si-PEI. Next, Si-PEI and PVP are dispersed in o-dichlorobenzene / n-butanol, and then COF monomer and glacial acetic acid are added. After maintaining the mixture at 110-130℃ for 70-80 hours, it is washed, dried, and ground to obtain Si@COF. Finally, Si@COF and cobalt acetate tetrahydrate are dispersed in methanol, reacted at room temperature, and then washed, dried, and ground to obtain Si@COF-Co. This invention offers a simple, high-yield, and effective method. The synthesized material effectively alleviates the volume expansion of nano-silicon, improves the stability and reversibility of the electrode material, and can be used as a negative electrode material for lithium-ion batteries.

The invention provides a negative active material, a negative active material coating, a negative pole piece, a cylindrical lithium ion battery and an electric device, and relates to the technical field of lithium ion batteries. The negative active material comprises graphite, silicon carbon, pre-lithium silica and monocrystalline silicon; wherein the total mass of the silicon carbon material and the pre-lithium silica accounts for less than 40% of the total mass of the negative electrode active material. According to the invention, the problem that the battery capacity and the cycle life are limited because the combination and the structural design of the existing lithium ion battery negative electrode material are not optimized enough is effectively solved.

The invention discloses a SiOxCy-coated integrated carbonaceous honeycomb framework material as well as preparation and application thereof, and belongs to the field of electrochemical energy storage and functional nano composite materials. The material is prepared by adopting a co-sacrifice template low-temperature pyrolysis strategy, and is realized through the steps of metal salt-colloidal crystal microsphere template precursor preparation, precursor compression molding, double-temperature-zone one-step roasting and the like. The preparation process is simple, the macrostructure is regular and controllable, and the chemical composition is adjustable; the graphene carbonaceous matrix is in three-dimensional interconnection with the SiOxCy nanoparticles, and the carbon nanotubes grow in situ. When used as a lithium ion battery negative electrode material, the material does not need traditional conductive agents, binding agents and current collectors, shows high reversible capacity and excellent cycling stability, and is suitable for the fields of electric automobiles, energy storage power stations, household energy storage, standby power supplies and the like.

The invention belongs to the technical field of battery materials, and mainly relates to a method for preparing porous carbon microspheres through microwave induction of high-entropy alloy-petroleum coke and application. The method comprises the following steps: performing low-temperature plasma activation treatment on crushed and sieved petroleum coke powder to obtain activated petroleum coke powder; mixing and reacting the activated petroleum coke powder with a salt solution containing at least five transition metals, and performing freeze drying to obtain a high-entropy alloy-petroleum coke composite material precursor; the high-entropy alloy-petroleum coke composite material precursor is subjected to microwave radiation treatment in an inert atmosphere, and a carbonized precursor of a spherical structure is obtained; and performing high-temperature activation treatment on the carbonized precursor with the spherical structure in an activation atmosphere, and performing acid pickling and drying to obtain the porous carbon microsphere material. According to the method, the porous carbon microsphere material with high specific surface area, high microporosity and excellent conductivity is prepared through plasma activation, multi-metal complexation, microwave radiation and high-temperature activation treatment, and can be applied to a negative electrode material of a lithium ion battery.

The invention relates to the technical field of lithium ion battery negative electrode materials, in particular to a preparation method of a silicon-carbon composite negative electrode material with improved safety, which comprises the following steps: (S1) reacting a first phenol monomer, a second phenol monomer and an aldehyde monomer, sequentially curing twice to obtain a phenolic resin block, and sequentially crushing, pre-oxidizing, pyrolyzing and carbonizing to obtain a silicon-carbon composite negative electrode material; pyrolytic carbon is obtained; the second phenol monomer is cardiac phenol; (S2) carrying out activated pore-forming on the pyrolytic carbon, and carrying out high-temperature treatment in an inert atmosphere to obtain porous carbon; and (S3) sequentially performing vapor phase silicon deposition and carbon coating on the porous carbon to obtain the silicon-carbon composite negative electrode material. By adjusting a monomer formula and a secondary curing process in resin synthesis, regulation and control on the hybridization degree of SP3 and SP2 are realized, the crosslinking degree and mechanical strength of the resin are improved, the defects of a porous carbon substrate are reduced, and a silicon-carbon negative electrode material with a certain grain size can be prepared during later-stage deposition; the high performance of the silicon-carbon negative electrode material is maintained, and the silicon-carbon negative electrode material also has higher safety.

The invention relates to an S-doped g-C3N4 coated modified graphite material, a preparation method thereof and a lithium ion battery negative electrode. The method comprises the following steps: mixing a g-C3N4 precursor with a sulfur source, and then carrying out heat treatment under the condition of shielding gas to obtain sulfur-doped graphite phase carbon nitride S-g-C3N4; carrying out plasma modification treatment on the surface of the graphite material by adopting plasma reaction gas to obtain modified graphite; mixing S-g-C3N4 with the modified graphite to obtain a mixed material; and calcining the mixed material in a protective gas environment to obtain the S-doped g-C3N4 coated modified graphite material. The invention also provides the graphite material prepared by the method and a lithium ion battery negative electrode prepared from the graphite material. The graphite material has relatively high conductivity, interface compatibility and structural stability.

The invention belongs to the technical field of lithium ion battery negative electrode materials, and particularly discloses a nanometer silicon / high-entropy alloy oxide / carbon composite lithium ion battery negative electrode material with a honeycomb-like three-dimensional hierarchical nanometer structure and a preparation method of the nanometer silicon / high-entropy alloy oxide / carbon composite lithium ion battery negative electrode material. The preparation method comprises the following steps: respectively adding PVP and silicon nanoparticles into deionized water, and stirring for 12-24 hours; adding oxysalts of iron, nickel, cobalt, chromium and manganese with equal molar weight, stirring for 12-24 hours, and then freeze-drying for 24-48 hours; and finally, putting the freeze-dried product into a tubular furnace, and calcining at high temperature in an inert atmosphere to obtain the composite lithium ion battery negative electrode material. A half battery prepared from the composite lithium ion battery negative electrode material prepared by the method has high initial specific discharge capacity and excellent capacity retention ratio, and the preparation method of the composite material is simple and convenient to operate, low in cost and suitable for large-scale production, and provides a new idea for preparation of a silicon-based composite electrode.

The invention discloses porous carbon with a gradient structure, a preparation method of the porous carbon and application of the porous carbon in a negative electrode of a lithium ion battery. The porous carbon has a gradient structure with compact micropores on the surface and loose macropores inside. The preparation method of the porous carbon comprises the following steps: carrying out oleophylic modification on SiO2 to obtain hydrophobic SiO2; carrying out hydrophilic coating on NH4Cl to obtain PVP (Polyvinyl Pyrrolidone) coated NH4Cl; the preparation method comprises the following steps: mixing coal pitch, methylbenzene, oleic acid, hydrophobic SiO2 and PVP (at) NH4Cl to form a suspension; preparing a spherical precursor by a micro-fluidic emulsification method; and carbonizing, sequentially carrying out oxygen plasma treatment and HF solution etching, and removing the template to obtain the porous carbon with the gradient structure. The gradient distribution of the template and the pore-forming agent is realized through surface modification difference and a microfluidic technology, the pore structure and the particle size can be accurately regulated and controlled, the process is simple, the compatibility is high, the prepared porous carbon can be used as a substrate for a silicon-carbon composite negative electrode material, the volume expansion of silicon can be effectively buffered, and the service life of the silicon-carbon composite negative electrode material is prolonged. And the first coulombic efficiency, the specific capacity and the cycling stability of the lithium ion battery are improved.

The invention provides a silicon-carbon composite negative electrode material, a preparation method of the silicon-carbon composite negative electrode material, a lithium ion battery negative electrode plate containing the silicon-carbon composite negative electrode material and a lithium ion battery, and relates to the technical field of lithium ion batteries. The silicon-carbon composite negative electrode material comprises a porous carbon skeleton, silicon distributed in internal pores of the porous carbon skeleton, and a functional interface layer covering the outer surface of the skeleton, wherein no free silicon elementary substance exists on the outer surface of the porous carbon skeleton, and the functional interface layer comprises a metal fluoride passivation layer formed by reacting metal elements doped in the carbon skeleton with a fluorine-containing etching agent; and the hybrid electrolyte coating layer is formed by reacting an oxygen-containing or nitrogen-containing functional group grafted on the surface of the carbon skeleton with a fluorine-containing etching agent. According to the technical scheme, the stable interface layer with passivation protection and ion conduction functions can be constructed in situ while high-activity silicon on the surface is removed, so that the first coulombic efficiency, the cycling stability and the rate capability of the battery are remarkably improved, side reactions are reduced, and the safety of the battery is improved.

The invention relates to a preparation method and application of a Si (at) C (at) rGO (at) N (at) P silicon carbon composite material, and belongs to the technical field of lithium ion battery negative electrode materials. The preparation method comprises the following steps: carrying out ball milling on POSS particles in a ball mill to obtain powder, adding the obtained powder into a GO dispersion liquid, adding an ionic liquid IL-C = N, carrying out ultrasonic dispersion to obtain a mixed liquid, putting the mixed liquid into a high-pressure hydrothermal kettle, carrying out a reaction, adding TPP into the obtained IL-POSS-GO aerogel, carrying out mixed ultrasonic treatment, drying, calcining in a tubular furnace, washing and drying to obtain the N / P co-doped porous silicon-carbon composite material Si (at) C (at) rGO (at) N (at) P. When the silicon-carbon composite material is used for preparing a negative electrode material of a lithium ion battery, the battery is endowed with good cycle performance, relatively high reversible specific capacity and first coulombic efficiency, and the overall electrochemical performance is excellent.

The invention provides a lithium ion battery negative electrode material as well as a preparation method and application thereof. The lithium ion battery negative electrode material is a porous silicon carbon material coated with lithium phosphate. The preparation method is simple and efficient, lithium phosphate salt is uniformly distributed on the surface of the porous silicon carbon material through solvent wet coating, the lithium phosphate salt is decomposed into LiF and LixPyOz through sintering and heating, and LiF and LixPyOz coating layers are generated in situ on the surface of the porous silicon carbon negative electrode material of the lithium ion battery, so that the porous silicon carbon material uniformly coated with LiF and LixPyOz is obtained, the advantages of LiF and LixPyOz are combined, and the porous silicon carbon material has the advantages that the porous silicon carbon material can be used for preparing the lithium ion battery negative electrode material through cooperation of LiF and LixPyOz; the silicon-carbon material prepared by the method has the characteristics of high strength, high stability and high ionic conductivity, can effectively inhibit volume expansion of the silicon-carbon material in the charge-discharge process, block penetration of electrons and reduce capacity loss of the silicon-carbon material in the reaction process, is used for manufacturing a lithium ion battery and remarkably improves the cycling stability of the battery.

The invention relates to the technical field of battery silicon negative electrodes, in particular to a silicon-carbon composite material and a preparation method and application thereof. The silicon-carbon composite material comprises a three-dimensional through mesoporous carbon skeleton, nano silicon particles loaded in mesopores and a gradient carbon coating layer, nano silicon and the carbon skeleton are connected through Si-O-C covalent bonds, and the gradient carbon coating layer is composed of a soft carbon inner layer, a graphitized carbon middle layer and a compact hard carbon outer layer. The preparation method comprises three steps of synthesis of a three-dimensional through mesoporous carbon skeleton, confinement silicon loading and gradient carbon coating. The material solves the problems of silicon particle agglomeration, volume effect and interface instability, has excellent electrochemical performance, can be used as a lithium ion battery negative electrode material, is suitable for a next-generation high-energy lithium ion battery, and improves the cycling stability and capacity performance of the battery.

The invention discloses a high-entropy sulfur selenide and preparation and application thereof, the high-entropy sulfur selenide is a Co9S8 compound doped with cations and anions, the doped cations are Fe, Ni, Mo and V, the doped anions are Se, each doped cation and anion are uniformly doped in Co9S8 crystal lattices, the molar ratio of Fe to Co to Ni to Mo to V is (8-11): 10: (8-11): (8-11): (8-11), and the molar ratio of S to Se is (5-15): 1. The invention provides application of the high-entropy sulfur selenide as a lithium ion battery negative electrode active material, and provides a lithium ion battery. According to the high-entropy sulfur selenide disclosed by the invention, the lithium ion battery can have excellent long cycle stability, high specific capacity and high-rate charge-discharge performance.

The invention relates to a negative electrode slurry and a preparation method thereof, a negative plate and a lithium ion battery, the negative electrode slurry mainly comprises a negative electrode active material, a binder composition, a conductive agent and a negative electrode additive, the mass ratio of the binder composition to the negative electrode additive is 2.0-2.4: 1.0-2.0, the binder composition comprises a component A, a component B and a component C, the component A is a fluorine-containing polymer, the component C is a fluorine-containing polymer, and the component B is a fluorine-containing polymer. The component B comprises a carboxylic acid compound, the component C is carboxymethyl cellulose salt, the negative electrode additive is alkali metal fluoride salt and / or alkaline earth metal fluoride salt, the pH value of the negative electrode slurry is 6.5-7.5, and the viscosity of the negative electrode slurry is 1000-4000 mpas. The negative electrode slurry disclosed by the invention has good dispersity and stability, and the prepared negative electrode plate can effectively relieve volume expansion of silicon, so that the rate capability, the cycling stability, the coulombic efficiency and the battery safety of the lithium ion battery can be effectively improved, and the consistency of the lithium ion battery is improved.