16972results about "Cell electrodes" patented technology

The invention relates to a method for preparing a lithium iron phosphate / carbon composite material of a lithium ion battery, which belongs to the technical field of lithium ion batteries. The method for preparing the lithium iron phosphate / carbon composite material of the lithium ion battery comprises the following steps of: 1) preparing a suspending graphene-dispersed aqueous solution system, namely, crushing graphite to 1 to 5 microns, adding the crushed graphite into distilled water or purified water, adding 0.1 to 5 percent of surfactant, heating with stirring the mixed solution to 180 to 250 DEG C in a sealing way, performing stirring for 2 to 6 hours and reducing the temperature; 2) crushing lithium iron phosphate to the particle size of 1 to 5 microns, adding the crushed lithium iron phosphate into the distilled water or the purified water, adding with stirring 0.01 to 1 percent of coupling agent, performing uniform stirring, adding the graphene-dispersed aqueous solution, and performing stirring and filtration; and 3) vacuum-drying solid powder obtained by the filtration, and calcinating the dried solid powder for 2 to 12 hours to obtain the graphene-coated lithium iron phosphate cathode material. The method has the advantages of simple process, high material performance, high conductivity, high bulk density, high compacted density and the like.

The invention discloses an asphalt-based hard carbon material as well as a pre-oxidation preparation method and application thereof. Belongs to the technical field of asphalt-based hard carbon materials. The pre-oxidation preparation method comprises the following steps: carrying out primary pre-oxidation treatment on asphalt at 250-400 DEG C in air flow of 50-500mL / min; crushing the obtained primary pre-oxidized asphalt, and then carrying out secondary pre-oxidation treatment at 250-400 DEG C in air flow of 50-500mL / min to obtain secondary pre-oxidized asphalt; and carrying out carbonization treatment on the secondary pre-oxidized asphalt. According to the method, the asphalt can be kept in a solid-phase state to be subjected to efficient and thorough oxidation cross-linking reaction, the production cost is reduced, the obtained asphalt-based hard carbon material has high first coulombic efficiency and high capacity, and powerful support is provided for commercial application of sodium-ion battery negative electrode materials and rapid development of an energy storage technology.

The invention provides a solid electrolyte slurry, an electrode slurry, a solid electrolyte sheet, an electrode sheet, a solid battery monomer, a battery device and a power utilization device.The solid electrolyte slurry comprises a sulfide solid electrolyte material, a solvent and a binder dissolved in the solvent, and the solvent is a non-polar solvent, a weak-polar solvent or a mixed solvent of the non-polar solvent and the weak-polar solvent; the binding agent comprises a polyacrylate binding agent and a non-polar polyolefin binding agent. The slurry disclosed by the invention has high dispersity, high suspension property and good cohesiveness, and can enable the solid-state battery monomer to have high initial coulombic efficiency when being used in the solid-state battery monomer.

The invention provides a comb-shaped polymer binder, a pole piece and a battery, the comb-shaped polymer binder comprises an acrylate main chain, a flexible soft segment, a polar hard segment and a functional chain segment, the flexible soft segment, the polar hard segment and the functional chain segment are respectively grafted on the acrylate main chain, the flexible soft segment comprises an ether chain segment and / or an ester chain segment, the polar hard segment comprises a polar group and / or a first heteroaromatic ring group, and the functional chain segment comprises a functional group and a second heteroaromatic ring group. The functional chain segment comprises an aromatic ring group containing a pi-conjugated structure and / or a second heteroaromatic ring group containing a pi-conjugated structure. The comb-shaped binder adopts a structural design of'hard section anchoring + soft section buffering + functional side chain ', is helpful for enabling the binder to have high peel strength, stress buffering and electron conduction capabilities at the same time, is compatible with an existing wet coating-rolling process, is helpful for improving the peel strength and prolonging the cycle life of an electrode plate when being used for preparing the electrode plate, and is beneficial for improving the service life of the electrode plate. And the rate capability of the battery is improved.

The invention provides a biomass-derived spherical porous carbon material and a preparation method thereof, and a silicon-carbon negative electrode material and a preparation method thereof, and relates to the field of lithium ion batteries. The preparation method of the biomass-derived spherical porous carbon material comprises the following steps: carrying out pre-carbonization treatment on vinasse to obtain pre-carbonized vinasse, mixing the pre-carbonized vinasse with an acidic solution, and washing with water until the mixture is neutral to obtain pre-treated vinasse; mixing the pretreated vinasse with a pore-forming agent, a binder and water to prepare slurry, and performing spray drying on the slurry to obtain a spheroidized precursor; carrying out carbonization treatment on the spheroidized precursor; washing the carbonized spheroidized precursor with water until the spheroidized precursor is neutral, and drying the spheroidized precursor to obtain an intermediate; and activating the intermediate with water vapor to obtain the biomass-derived spherical porous carbon material. The material with a regular spherical and porous structure can be prepared, the material can be used for preparing a silicon-carbon negative electrode material with a stable structure, and the electrochemical performance of the silicon-carbon negative electrode material is improved.

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 belongs to the technical field of lithium ion batteries, and particularly relates to a self-repairing type lithium ion battery positive electrode adhesive, a preparation method, positive electrode slurry and a positive electrode plate. The adhesive comprises a mixed solvent, and a first copolymer serving as a main component and a second copolymer serving as a cross-linking agent are dissolved in the mixed solvent; the first copolymer is an acrylate-based multipolymer containing carboxyl or hydroxyl; the second copolymer is isocyanate terminated UPy functional polyurethane; the adhesive is in a liquid state at room temperature, when the adhesive is subjected to vacuum heat treatment at 60-180 DEG C, carboxyl or hydroxyl in main components of the adhesive reacts with isocyanate groups of a cross-linking agent to form amido bonds along with volatilization of a mixed solvent, and UPy groups are associated through quadruple hydrogen bonds to form dual dynamic cross-linking points. The method can effectively adapt to the volume change of the positive electrode material in the lithium removal / insertion process, and maintains the integrity of the electrode structure, thereby improving the cycling stability and rate capability of the lithium ion battery.

The invention provides a high-stability lithium-rich manganese-based positive electrode material and a preparation method thereof, and relates to the technical field of lithium-rich manganese-based positive electrode materials, and the method comprises three steps of preparation of a homogeneous precursor, solid-state mechanical fusion doping and coating, and high-temperature sintering; a lithium-rich manganese-based precursor is prepared by adopting a homogeneous coprecipitation process, uniform distribution of metal ions is ensured, then an aluminum source, a zirconium source and a fluorine source are introduced as doping agents, phosphate and a titanate coating agent are combined, doping and coating integrated treatment is realized through mechanical ball milling, and the lithium-rich manganese-based composite material is obtained. And finally, mixing with a lithium source in an argon atmosphere, and carrying out high-temperature sintering of temperature programming and staged heat preservation to form a stable composite coating layer in situ. Therefore, manganese ion migration is effectively inhibited through lattice doping, a layered structure is prevented from being converted into spinel or rock salt phase, meanwhile, a nanoscale ion / electron transmission channel is constructed, interface impedance is reduced, and the charging and discharging efficiency under high voltage is improved.

The invention relates to the technical field of proton exchange membrane fuel cell cathode catalysts, and discloses a nanoscale high-entropy intermetallic compound catalyst and a preparation method and application thereof. According to the nanoscale high-entropy intermetallic compound catalyst, a nitrogen-doped porous carbon material derived from zeolite imidazole skeleton-8 is taken as a carrier, and the metal elements of a high-entropy intermetallic compound comprise platinum, copper, cobalt, nickel and iron or platinum, ruthenium, copper, cobalt, nickel and iron. The preparation method of the catalyst comprises the following steps: step 1, preparing a zeolite imidazole framework 8; 2, preparing and purifying a nitrogen-doped porous carbon material carrier; step 3, loading a metal precursor; and 4, preparing the nano-scale high-entropy intermetallic compound catalyst. Nanoscale, high dispersity and structure ordering of the high-entropy intermetallic compound are achieved, the high-entropy intermetallic compound serves as a PEMFC cathode catalyst, the ORR quality activity and durability can be remarkably improved, and Pt loading capacity and cost are effectively reduced.

The application relates to the technical field of material preparation, and discloses multi-element carbon-coated lithium manganate, a preparation method thereof and a secondary battery. The multi-element carbon-coated lithium manganate comprises a lithium manganate core and a carbon nanotube layer and a hard carbon layer which are sequentially coated on the lithium manganate core. The chemical formula of the lithium manganate core is LiAl a X b Mn 2‑a‑b O4, wherein 0.01<=a<=0.10, 0.01<=b<=0.05, and X comprises at least one of Co, Cr, Ti, V and B. The preparation method of the multi-element carbon-coated lithium manganate comprises the following steps: (I) preparing doped lithium manganate, (II) preparing carbon nanotubes and (III) multi-element carbon coating. The multi-element carbon-coated lithium manganate has high conductivity, rate performance, cycle performance and safety performance, and can be used as an alternative positive electrode material with high cycle and excellent fast-charging performance.

The invention relates to the technical field of lithium ion batteries, in particular to a composite layered oxide positive electrode material, a preparation method and a lithium ion battery. The composite layered oxide positive electrode material provided by the invention comprises a ternary material core, wherein the ternary material core is a high-nickel ternary oxide doped with Zr and Mg in a gradient manner; the coating layer shell comprises a first coating layer and a second coating layer, the outer side of the first coating layer is coated with the second coating layer, the first coating layer is a composite layer of fluorine-terminated MXene and sulfide solid electrolyte, and the second coating layer is a porous high-entropy oxide. The composite layered oxide positive electrode material provided by the invention has high specific capacity, excellent cycling stability, first coulombic efficiency and high rate performance, is compatible with existing industrial production, and remarkably improves the comprehensive performance and practical value of the lithium ion battery.

The invention provides a sphere-like silicon-carbon negative electrode material and a preparation method and application thereof, and particularly relates to the technical field of negative electrode materials, the negative electrode material comprises a sphere-like porous carbon skeleton, silicon nanoparticles distributed in the sphere-like porous carbon skeleton, and an amorphous carbon layer coating the surface of the sphere-like porous carbon skeleton, the particle appearance of the sphere-like porous carbon skeleton is of a round irregular or asymmetric polyhedral structure and comprises one or more of a potato shape, an ellipse shape, an olive shape, a long strip shape and a pomegranate shape, the particle of the sphere-like porous carbon skeleton is provided with a plurality of asymmetric faces, fillets are formed between the faces, and the radius of the fillets does not exceed 20 microns. The problem of structural damage of the material under the action of external force such as rolling can be effectively relieved, good mechanical stability is kept, excellent bonding performance can be achieved in the electrode coating process, the ion transmission path of the material is improved, and the electronic conductivity and the lithium ion diffusion performance are improved.

Provided in the present disclosure are a sodium ion battery, a preparation method for the sodium ion battery, an electrical device and a hard carbon material. The sodium ion battery comprises a negative electrode sheet; the negative electrode sheet comprises a negative electrode current collector and a negative electrode film layer located on at least one surface of the negative electrode current collector; the negative electrode film layer comprises a hard carbon material. On the basis of measurement using the nitrogen adsorption method, the hard carbon material comprises a porous structure, and the porous structure comprises pores having a pore size of 2 nm-8 nm; on the basis of measurement using the nitrogen adsorption method, the pore volume of the pores having a pore size of 2 nm-8 nm is 0.0004 cm3 / g-0.0040 cm3 / g.

The application discloses a kind of carbon nanotube / polyaniline composite modified epoxy resin conductive paint and preparation method thereof, belong to coating technical field.The application is prepared by preliminary disentangling carbon nanotube with specific solvent, and the carbon nanotube dispersion liquid uniformly dispersed is obtained;Afterwards, polyaniline is added to carbon nanotube dispersion liquid, and carbon nanotube / polyaniline composite is prepared by solvent evaporation or purification;Finally, carbon nanotube / polyaniline composite is compounded with epoxy resin, and high-performance carbon nanotube / polyaniline composite modified epoxy resin conductive paint is obtained.The carbon nanotube / polyaniline composite modified epoxy resin conductive paint prepared by the application has more excellent mechanical properties and electrical properties than traditional conductive paint, and can be better applied in aerospace, battery, communication, new energy and other aspects.

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

The invention provides a preparation method of a cobalt-based bimetallic alloy positive electrode lithium supplement composite material and an application technology of the cobalt-based bimetallic alloy positive electrode lithium supplement composite material in a battery. The lithium-supplementing composite material is a lithium salt, a cobalt-based bimetallic alloy catalyst for promoting low-pressure decomposition of the lithium salt, and a positive electrode material. The lithium salt is lithium oxalate, the cobalt-based bimetallic alloy catalyst is prepared from nitrogen and sulfur co-doped carbon impregnated in a transition metal salt solution through freeze drying and high-temperature calcination, and the positive electrode material comprises one of lithium iron phosphate, lithium cobalt oxide and ternary high nickel (LiMO2, M = Ni, Co and Mn). When the lithium supplement agent is applied to a secondary lithium ion battery, the decomposition voltage of the lithium supplement agent can be reduced, the irreversible loss of capacity is reduced, and the initial coulombic efficiency is improved.

The invention discloses a silicon negative electrode binder as well as a preparation method and application thereof. The silicon negative electrode binder is a graft copolymer with a comb-shaped structure; the grafted copolymer comprises a polyurethane chain segment forming a main chain of the comb-shaped structure, a polyacrylic acid chain segment serving as a branch chain and connected to the main chain through a covalent bond, and a fluorine-containing chain segment. According to the preparation method, a graft copolymerization method is adopted, the preparation method is carried out in a water-based system, the silicon negative electrode binder with hardness and softness is obtained, and the silicon negative electrode binder is applied to a lithium battery through the synergistic effect of mechanical property, interface stability and electrochemical performance. And a solution of a key material is provided for a high-capacity and long-cycle lithium battery which takes an active material with high silicon content as a negative electrode.

The invention belongs to the technical field of lithium batteries, and particularly relates to a lithium-rich manganese-based positive electrode material and a preparation method and application thereof. The preparation method comprises the following steps: mixing a metal salt solution, a precipitator and a complexing agent, and carrying out coprecipitation reaction on an obtained coprecipitation reaction precursor solution to obtain a lithium-rich manganese-based precursor; the metal salt solution comprises a manganese element, a cobalt element and a nickel element; and mixing the lithium-rich manganese-based precursor, a lithium source, an auxiliary agent and a dispersing agent, and calcining to obtain the lithium-rich manganese-based positive electrode material, the auxiliary agent comprises a nitrogen source or a nitrogen source and a carbon source. The first discharge specific capacity, the rate capability and the cycling stability of the lithium-rich manganese-based positive electrode material can be improved, and the problems of capacity fading, discharge voltage drop and dynamic delay in an electrochemical reaction process are solved.

The invention discloses a Prussian blue type composite positive electrode material and a preparation method and application thereof, and the Prussian blue type composite positive electrode material provided by the invention is composite powder containing a Prussian blue type positive electrode material, a conductive agent, a binder and a functional additive, the mass ratio of the Prussian blue positive electrode material to the conductive agent to the binder to the functional additive is (90-99): (1-5): (0-5): (0-0.5). According to the Prussian blue composite positive electrode material provided by the invention, the components are uniformly distributed, the Prussian blue composite positive electrode material has the characteristics of high compaction, easy dispersion, relapse resistance, high conductivity and the like, and the Prussian blue composite positive electrode material can be directly used for wet homogenization and can also be directly used for dry electrode manufacturing.

The invention relates to the technical field of lithium battery negative electrode binders, in particular to a two-component negative electrode binder and a using method thereof.The two-component negative electrode binder comprises a component A and a component B. The component A is formed by copolymerization of acrylamide substances, fluorinated acrylate substances and acrylic acid, and the component B is formed by copolymerization of fluorinated acrylate substances and acrylic acid. The component B is formed by copolymerizing acrylic acid, acrylate, a fluorinated acrylate substance, an acrylamide substance and sulfydryl acrylate, and the component A accounts for 30wt%-70wt% of a mixture of the component A and the component B during use; when the adhesive is used for preparing the negative electrode slurry, a glue solution A and a glue solution B are prepared respectively, the glue solution A is added after the solid raw materials are subjected to dry mixing, the glue solution B is added after the solid raw materials are fully stirred, and finally the leveling aid is added. The two-component negative electrode binder provided by the invention has both rigidity and softness, strong binding power with a main material, strong self-adaptive expansion capability, high release force retention rate after long circulation, and good interface stability.

The invention provides a lithium ion battery and an electric device, the lithium ion battery comprises a positive electrode, a negative electrode, a diaphragm and an electrolyte, the positive electrode comprises a positive electrode active material layer, the positive electrode active material layer comprises a positive electrode active material and an oxide solid electrolyte, and the surface of the diaphragm is provided with an oxide solid electrolyte layer; the electrolyte comprises a solvent, a lithium salt, a first additive and a second additive, the first additive comprises fluoroethylene carbonate, and the second additive comprises 1, 3-propane sultone; the lithium ion battery satisfies the following conditions: 0.72 < = (H + X) / P < = 8; 0.5 < = (A + B) / (H + X) < = 8.89; 0.16 < = H / X < = 6.4; 0.5 < = A / B < = 12. According to the lithium ion battery provided by the invention, the safety and the high and low temperature performance of the positive electrode of the lithium ion battery are remarkably improved through multi-component cooperative regulation and control, further, when the lithium ion battery meets the limitation of the relational expression at the same time, the interface impedance can be reduced to the maximum extent, and the performance of the lithium ion battery can be improved through cooperation of multi-component parameters. And synchronous optimization of thermal safety, low-temperature discharge capacity and high-temperature cycle life of the battery is realized.

The invention belongs to the technical field of batteries, and particularly discloses a secondary battery, a battery pack and an electric device. A negative electrode film layer of the secondary battery contains an additive; the additive comprises a carboxymethyl cellulose compound and a modified compound thereof; the compound is beneficial to improving the ionic conductivity of alkali metal ions and reducing the diffusion polarization phenomenon, so that the internal resistance of the battery is reduced. And the content of the additive in the negative electrode film layer close to the current collector is controlled to be higher than the content of the additive in the negative electrode film layer far away from the current collector, so that the technical effects of reducing the internal resistance of the battery, controlling the cost and reducing the influence on the energy density of the battery are achieved.

A kind of preparation method of high compaction lithium iron phosphate of multistage gradation, including step one: iron source, phosphorus source, lithium source, carbon source, dispersing agent, element dopant and solvent are dispersed according to proportion, slurry after dispersion is divided into A, B, C three slurry according to proportion, three slurry are grinded respectively, and then are respectively carried out spray drying;Step two: three spray materials are respectively pre-sintered at different temperatures, and pre-sintered material is respectively crushed;Step three: the material after pre-sintering is mixed to realize multistage particle gradation.Certain mass ratio of carbon source and pre-crushed material are dry mixed;Step four: after secondary sintering, crushing and magnetic removal process, the multistage gradation high compaction lithium iron phosphate positive material is obtained.The present application realizes particle gradation of once sintered material, secondary carbon coating and sintering strengthening by grading particle size design, and realizes the collaborative improvement of compaction density and specific capacity of lithium iron phosphate positive material.

The application discloses a kind of derived biomass hard carbon material pulverization process, belong to biomass charcoal material processing technical field, first, pulverization process includes the following steps: after drying, the coconut shell derived hard carbon block is carried out primary crushing, while spraying first modifier, obtain the particle size 1~3mm of coarse crushing modified particle;Coarse crushing modified particle is carried out secondary precision crushing under argon atmosphere, while spraying second modifier, obtain the precision crushing modified particle of D 50 Particle size is 15 μm;Precision crushing modified particle is carried out roll grinding spheroidization, while spraying third modifier, obtain the spherical modified particle of D 50 Particle size is 10 μm;Spherical modified particle is carried out flash drying after cooling, then add magnesium stearate to it, after mixing, obtain derived biomass hard carbon material.Then, the application realizes breakthrough in tap density, particle size distribution, first efficiency and other core indexes by the coordination of three-stage gradient modification and progressive pulverization process.

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

The invention discloses a method for preparing a hard carbon negative electrode material, the hard carbon negative electrode material and a sodium-ion battery, belongs to the technical field of energy materials, and solves the problems that the existing hard carbon negative electrode material is complex in microstructure and indefinite in sodium storage mechanism, and the traditional preparation method cannot effectively increase the internal closed pore volume, so that the high-platform capacity development is limited, and the sodium-ion battery is difficult to use. And the improvement of the energy density of the sodium-ion battery is restricted. Comprising the following steps: drying and crushing coconut shells; pre-carbonizing the treated coconut shell to obtain a carbonized material; uniformly mixing the carbonized material with an activating agent to obtain a mixed material; carrying out an activation reaction to obtain a biomass-based porous carbon mixed material; washing until the solution is neutral; carrying out activation reaction on the washed material to obtain the biomass-based porous carbon material with high specific surface area and high microporosity; and carrying out variable-temperature chemical vapor deposition reaction to obtain the hard carbon negative electrode material. The method is suitable for a large-scale preparation scene of the hard carbon negative electrode material with abundant closed pores.

The invention relates to the field of electrode material preparation, in particular to a graphene local in-situ coated electrode material and a preparation method thereof. The preparation method comprises the following steps: mixing a powdery electrode material with graphite, wherein the mass ratio of the graphite to the powdery electrode material is (0.0001-0.01): 1; and then mechanical grinding is carried out, so that the graphite forms graphene in situ under the action of mechanical force, the surface of the electrode material is coated with the graphene in situ by utilizing the adsorption force of a newly-generated nano surface and mechanical work, and the graphene locally-modified composite electrode material is obtained. According to the preparation method, extremely low graphite consumption is controlled, in-situ generation and coating of graphene are realized by utilizing a mechanical grinding one-step method, complex steps such as independent preparation of graphene and high-temperature sintering are omitted, the process is simple, and the cost is low; and the complete shielding of an ion transmission channel is avoided while an electronic conductive network is effectively constructed, so that the capacity, the cycling stability and the rate capability of the electrode material are remarkably improved.

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 relates to the technical field of batteries, in particular to a negative electrode material, a preparation method thereof and a battery. The negative electrode material comprises a silicon nano material; the metal silicide layer at least partially coats the surface of the silicon nano material; the nitrogen and sulfur doped carbon layer at least partially coats the surface of the metal silicide; and the thickness of the metal silicide layer is greater than that of the nitrogen and sulfur doped carbon layer. According to the negative electrode material, the preparation method thereof and the battery provided by the invention, the coating structure of the negative electrode material is optimized, and the metal silicide / heteroatom doped carbon double-layer coated silicon nano material can be prepared by adopting a synthesis method which is low in energy consumption and capable of constructing a functional multi-layer coating structure, so that the long cycle life and the high-rate fast charging performance can be considered at the same time.