2666 results about "Carbon composites" 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 relates to the field of lithium battery negative electrode materials, and particularly discloses a silicon-carbon composite negative electrode material for a lithium ion battery and a preparation method of the silicon-carbon composite negative electrode material. The method comprises the following steps: preparing a porous carbon substrate, and depositing silicon nanoparticles in pores and on the surface of the porous carbon substrate by adopting a fluidized bed chemical vapor deposition process and taking silane as a silicon source to obtain a silicon-carbon core material; continuously carrying out carbon coating on the surface of the silicon-carbon core material in the fluidized bed by taking acetylene as a carbon source to form a carbon coating layer; and leading out the obtained material from the fluidized bed, taking acetylene as a carbon source, and carrying out carbon coating on the surface of the primary carbon coating layer again by adopting the rotary furnace to form a secondary carbon coating layer. According to the preparation method, a porous carbon matrix and double-layer functional carbon coating process is adopted, so that the volume expansion of silicon in the circulation process is remarkably inhibited, the interface side reaction is reduced, and the circulation stability of the material is effectively improved.

The invention discloses a silicon-carbon negative electrode material, porous carbon and a preparation method, the porous carbon is prepared by mixing ammonium fluoride and a pre-carbonized material to prepare a premix; and putting the premix in an inert atmosphere, and carrying out pre-activation, drying, carbonization, activation and crushing treatment to obtain the composite material. And uniformly depositing the nano silicon particles into the porous carbon skeleton through a mature CVD (Chemical Vapor Deposition) process to obtain the silicon-carbon composite material. Fluorine and nitrogen co-doping modification can increase the defect degree of a carbon skeleton, efficiently relieve mechanical stress accompanied by lithium storage volume expansion of the silicon negative electrode in a micro scale, provide abundant lithium ion transport and mass transfer channels and enhance the conductivity of porous carbon, and ammonium fluoride is used as a supplementary activator besides water vapor, so that the porosity of the porous carbon is further improved, and the conductivity of the porous carbon is improved. An effective space is provided for uniform deposition of silicon, the fluorine-containing carbon layer can induce formation of a high-stability SEI film rich in LiF on the surface of the nano silicon material, and the interface stability and coulombic efficiency of the silicon negative electrode are further improved.

The invention relates to a silicon-carbon composite material and a preparation method and application thereof.The preparation method comprises the steps that a porous graphite raw material is subjected to acid pickling and smashing to obtain pretreated porous graphite, then the pretreated porous graphite is soaked in a carbon precursor solution in a vacuum mode, carbonization treatment is conducted after centrifugal separation, pores of the porous graphite are filled with carbides, physical activation is conducted, and the silicon-carbon composite material is obtained; the preparation method comprises the following steps: forming pores in a carbide to form a graded pore structure to obtain a porous graphite composite material, then carrying out silicon deposition in a fluidized bed to obtain a uniform nano silicon layer, and then carrying out carbon coating treatment to obtain a silicon-carbon composite material; the graphite with relatively low cost is adopted as a matrix, high capacity and long cycle performance of the graphite-based silicon-carbon negative electrode material are realized through hierarchical pore structure design, carbonization-activation synergistic pore forming and interface deposition process optimization, and the graphite-based silicon-carbon negative electrode material can be applied to the fields of power batteries and high-energy-density energy storage, especially the field of lithium ion batteries and has wide application prospects. The expansion rate of the battery can be reduced, and the specific capacity, cycling stability and safety of the lithium ion battery can be improved.

The invention relates to the technical field of electrode materials, in particular to a silicon-carbon negative electrode material and a preparation method and application thereof. The silicon-carbon negative electrode material comprises a plurality of silicon-carbon composite particles, each silicon-carbon composite particle comprises porous carbon, nano silicon particles and phosphorus element which are attached in pores of the porous carbon, and coating carbon for coating the porous carbon, and n-type doping of the phosphorus element is formed at the joint of the nano silicon particles and the porous carbon. The preparation method comprises the following steps: (1) adsorbing phosphoric acid in porous carbon, and carrying out a heating reaction in a protective gas atmosphere to generate phosphorus-infiltrated porous carbon; (2) introducing a gaseous silicon source in a protective gas atmosphere, and carrying out silicon deposition on the phosphorus-infiltrated porous carbon by adopting a chemical vapor deposition method to obtain a phosphorus-doped silicon carbon material; and (3) carrying out carbon coating on the phosphorus-doped silicon carbon material to obtain the phosphorus-doped silicon carbon material. According to the method, the rate capability of the silicon-carbon negative electrode material can be remarkably improved while high first efficiency and high gram capacity are ensured.

The invention relates to a silicon-carbon composite material capable of improving the cycling stability of a battery, a preparation method of the silicon-carbon composite material, a negative pole piece and a lithium ion battery. The carbon-silicon composite particle comprises a silicon-carbon inner core and a carbon coating layer, nano-silicon is attached in holes and / or on the surface of a porous carbon matrix to form the silicon-carbon inner core, and the carbon coating layer is coated on at least part of the surface of the inner core; the porous carbon matrix and the carbon coating layer are both doped with halogen. According to the silicon-carbon composite material, the electron conductivity of the silicon-carbon composite material is improved by doping the halogen in the porous carbon matrix inside the silicon-carbon composite material and the carbon coating layer outside the silicon-carbon composite material; and meanwhile, the porous carbon matrix, the inner core composed of the nano silicon and the carbon coating layer are mutually matched and have synergistic interaction, so that the volume expansibility and defects of the silicon-carbon composite material are reduced, and the cycle stability is improved.

The invention discloses a chitosan modified lithium iron phosphate and carbon composite positive electrode material and a preparation method thereof.The preparation method comprises the steps that 1, lithium hydroxide, phosphoric acid and ferrous sulfate heptahydrate are mixed to prepare a uniform and stable solution, and a lithium iron phosphate precursor is prepared through a solvothermal method; step 2, dissolving chitosan in an acetic acid aqueous solution, and magnetically stirring under a water bath condition until the chitosan is completely dissolved to prepare a chitosan solution; and 3, adding the lithium iron phosphate precursor into a chitosan solution, uniformly mixing, carrying out ball milling and freeze drying, and carrying out high-temperature carbonization treatment in an inert gas to obtain the chitosan modified lithium iron phosphate and carbon composite positive electrode material. The method is simple to operate, low in cost and uniform in product particle size distribution.

A silicon-carbon material, a preparation method therefor, a secondary battery, and an electric device. The silicon-carbon material comprises silicon-carbon composite particles; the silicon-carbon composite particles comprise a porous carbon material, nano-silicon grains and a silicon carbide material layer; the porous carbon material is provided with through pores, the nano-silicon grains are located in the through pores, and the silicon carbide material layer is partially located on through pore walls; the grain size of the nano-silicon grains is not smaller than the average pore diameter of the porous carbon material. The silicon-carbon material is used as an active material of a negative electrode sheet, thereby improving the cycle performance of batteries.

The invention discloses a polypyrrole / cobalt / nitrogen-doped carbon composite material with a coaxial hollow structure and a preparation method thereof, and belongs to the technical field of advanced functional composite materials. The method comprises the following steps: firstly, synthesizing a hollow polypyrrole nanotube by a soft template method; secondly, cobalt / nitrogen-doped carbon is synthesized by adopting a template guiding method; and finally, secondarily coating the outer surface of the cobalt / nitrogen-doped carbon with a polypyrrole layer by adopting an in-situ oxidative polymerization method to construct the polypyrrole / cobalt / nitrogen-doped carbon composite material with a coaxial hollow heterostructure, and the polypyrrole / cobalt / nitrogen-doped carbon composite material has a coaxial sandwich structure: the inner core is a nitrogen-doped carbon hollow tube, the middle layer is a nitrogen-doped porous carbon matrix embedded with cobalt nanoparticles, and the outer surface of the cobalt / nitrogen-doped carbon composite material is a porous carbon matrix embedded with cobalt nanoparticles. And the outer layer is a conductive polypyrrole coating layer. The preparation method provided by the invention can successfully realize in-situ confinement growth and stable combination of ZIF-67, and has the advantages of high repetition rate, high yield and simple method; by adjusting the proportion of polypyrrole in the composite material, good impedance matching and large dielectric loss can be realized, and excellent electromagnetic wave absorption performance can be obtained.

The invention discloses a LiAlO2 fast ion conductor coated silicon-carbon composite material as well as a preparation method and application thereof, and belongs to the technical field of lithium ion battery materials. The LiAlO2 fast ion conductor coated silicon carbon composite material has a core-shell structure; an inner core of the composite material is a silicon-carbon composite material, the silicon-carbon composite material is formed by coating a three-dimensional carbon material with an amorphous carbon layer and loading a nano silicon compound, a shell of the composite material is a LiAlO2 fast ion conductor layer, and the silicon-carbon composite material with a three-dimensional network structure is constructed, and the surface of the silicon-carbon composite material is coated with the LiAlO2 fast ion conductor layer, so that the composite material is obtained. According to the present invention, with the LiAlO2, the volume expansion of the nanometer silicon during the charge-discharge process can be effectively relieved, the stability of the silicon-carbon composite material structure can be improved so as to significantly improve the cycle performance of the battery, and the LiAlO2 can provide the rapid channel for the transmission of the lithium ion during the charge-discharge process so as to improve the rate performance of the battery;

The invention provides a high-temperature-resistant magnesia-carbon composite refractory brick and a preparation method thereof, and belongs to the technical field of magnesium oxide refractory wall bricks, the refractory brick comprises the following raw materials: double-layer modified magnesium oxide, modified crystalline flake graphite, zircon powder, modified liquid phenolic resin and a benzoxazine cross-linking agent; the double-layer modified magnesium oxide is obtained by firstly coating magnesium oxide with powder phenolic resin, aluminum oxide and zirconium oxide and then coating magnesium oxide with asphalt, micron magnesium oxide, zirconium oxide and calcium oxide; the modified crystalline flake graphite is obtained by coating crystalline flake graphite with strontium hydroxide, asphalt and boron carbide; the modified liquid phenolic resin is formed by mixing liquid phenolic resin with a silane coupling agent and a polyacrylate cross-linked polymer. Double-layer modified magnesium oxide, modified crystalline flake graphite and modified liquid phenolic resin are prepared by adopting special components and a method and are matched with zircon powder and a benzoxazine cross-linking agent for use, and a reasonable forming and sintering process is designed, so that the refractory brick has good high-temperature stability, oxidation resistance, thermal shock resistance and the like.

The invention provides a low-carbon concrete coarse aggregate close packing combination grading formula and a determination method, and relates to the technical field of building materials, the formula comprises a coarse aggregate skeleton, a fine aggregate, a low-carbon cementing material, water and an admixture, the coarse aggregate skeleton is composed of four different size fractions, and the purpose is to achieve the closest packing to reduce the cement requirement and improve the cement quality. The low-carbon cementing material is composed of cement, a conventional low-carbon mineral admixture and a low-carbon composite mineral admixture, and the low-carbon composite mineral admixture comprises an active component A and a micro-filling component B. The determination method comprises the steps of system characterization and model establishment, slurry skeleton iterative collaborative optimization and formula determination. The porosity is reduced to the maximum extent by optimizing coarse aggregate grading, the cement consumption is greatly reduced, meanwhile, through the synergistic effect of the high-performance, high-proportion and low-carbon admixture, the working performance, physical and mechanical properties and durability of the concrete are ensured, carbon emission and material cost are remarkably reduced, industrial solid waste is effectively utilized, and the economic benefit is increased. And green low-carbon preparation of the concrete is realized.

The invention relates to a silicon-carbon composite material with a porous structure and a preparation method thereof, and the silicon-carbon composite material with the porous structure comprises an N / P co-doped porous carbon skeleton with micropore, mesopore and macropore channel networks, and amorphous or low-crystalline nanometer silicon particles which are uniformly loaded in the porous carbon skeleton and have the average particle size of 15-40nm, the mass percent of silicon in the composite material is 40-60%, and good interface bonding is formed between silicon and carbon. The preparation method mainly comprises the following steps: firstly, preparing an N / P co-doped porous carbon skeleton through a template method in combination with high-temperature carbonization and N / P source co-pyrolysis; and hydrolyzing an organic silicon source in the carbon skeleton to form silicon dioxide, and performing low-temperature metal thermal in-situ reduction to obtain the nano-silicon loaded composite material. Through a unique porous carbon skeleton design and a precise in-situ composite strategy of nano silicon, the prepared material shows high specific capacity, high initial coulombic efficiency and excellent cycling stability and rate capability when being used as a negative electrode of a lithium ion battery.

The present invention relates to a silicon-carbon composite, a preparation method therefor, and an anode active material comprising same. The silicon-carbon composite includes silicon particles, silicon oxides, magnesium compounds, and carbon. As a molar ratio (O / Si) of oxygen (O) atoms to silicon (Si) atoms in the silicon-carbon composite satisfies 0.01 to 0.60, when the silicon-carbon composite is applied to an anode active material, the discharge capacity, initial efficiency, and capacity retention ratio after cycles of a lithium secondary battery may be simultaneously improved.

The invention discloses a unidirectional graphene fiber carbon / carbon composite material as well as a preparation method and application thereof, and belongs to the technical field of carbon / carbon composite materials. The preparation method comprises the following steps: adding phenolic resin powder into absolute ethyl alcohol to prepare a phenolic resin dipping solution; adding the graphene fiber bundle into a phenolic resin impregnation solution for impregnation under the conditions of normal temperature and normal pressure to prepare a pre-impregnated graphene fiber bundle; carrying out stepped heating curing on the pre-impregnated graphene fiber bundle, and then carrying out carbonization to prepare a pre-treated graphene fiber bundle; the pretreated graphene fiber bundles are arranged in parallel and stacked in the thickness direction, pressure is applied for fastening, and a one-way prefabricated body is obtained; and carrying out heat treatment on the unidirectional preform, densifying by adopting an isothermal chemical vapor infiltration process, and then carrying out graphitization treatment to obtain the unidirectional graphene fiber carbon / carbon composite material. The graphene fiber is pretreated to fill pores of the graphene fiber, so that the densification efficiency of the graphene fiber preform is improved, and finally, the heat conduction and mechanical properties of the composite material are enhanced.

The invention belongs to the technical field of sodium ion battery hard carbon negative electrode materials, and particularly relates to a phenolic resin asphalt super-crosslinking hard carbon composite active material and a preparation method and application thereof.The preparation method comprises the steps of phenolic resin precursor synthesis, oxidized asphalt precursor synthesis, super-crosslinking reaction and stepped carbonization; the preparation method comprises the following steps: reacting phenol with formaldehyde under the action of a catalyst to obtain a phenolic resin precursor; pre-oxidizing the coated asphalt in an air atmosphere to generate an asphalt precursor; the preparation method comprises the following steps: mixing a phenolic resin precursor with an asphalt precursor, adding an acid catalyst into an organic solvent, and performing reflux heating to form a chemically bonded three-dimensional cross-linked network structure; and sequentially carrying out low-temperature pre-carbonization and high-temperature carbonization in an inert gas atmosphere to obtain a target product, namely the hard carbon composite material. The target product provided by the invention has rich closed pore and multistage through pore structure hard carbon, and the sodium storage capacity of the hard carbon material is effectively improved.

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 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 belongs to the field of silicon-carbon negative electrode material manufacturing, and particularly relates to a preparation method of a vapor deposition silicon-carbon material based on supercritical carrier gas. The method comprises the following steps: carrying out vacuum degassing on a porous carbon material in a heating state, then taking supercritical gas as carrier gas, assisting with ultrasonic vibration, introducing silicon-containing gas to carry out silicon deposition, and repeatedly carrying out operation until the required silicon content is reached; and finally, introducing a carbon source gas for carbon coating to obtain the silicon-carbon composite material with the core-shell structure. According to the preparation method, uniform deposition of silicon in a porous carbon skeleton is realized through silane vapor deposition with supercritical fluid as carrier gas under the assistance of ultrasonic vibration, the first coulombic efficiency is improved, stress concentration and volume expansion in the charging and discharging process are reduced, and the cycling stability is improved.

The invention discloses a silicon-carbon composite negative electrode material, a negative electrode plate, a preparation method and application. The silicon-carbon composite negative electrode material is of a double-coating structure and sequentially comprises inner core silicon, a lithium phosphate layer and a fluorine-containing carbon layer from inside to outside, and the mass ratio of the lithium phosphate layer to the inner core silicon is (1-5): 100. When the composite material is applied to a lithium ion battery, the core silicon and the specific double coating layers can improve the fast charging performance and the first effect while optimizing an ion transmission path; a specific double-coating structure can be used as a buffer layer, stress generated by volume expansion of silicon can be released, and pulverization of particles is avoided; and moreover, LiF with high ionic conductivity and higher mechanical strength and an SEI film with more stable regulation and control are formed through reaction with an electrolyte, so that the structural integrity of the material is kept, and the cycle performance of the material is improved.

The invention relates to a graphite silicon carbon composite negative electrode material, a negative electrode plate and a lithium ion battery, and belongs to the technical field of battery negative electrode materials. The graphite silicon carbon composite negative electrode material comprises a graphite inner core and a composite shell layer, the composite shell layer coats the surface of the inner core, the composite shell layer comprises a continuous carbon layer, the carbon layer is of a porous structure, and the porous structure is filled with nano silicon particles. According to the core-shell structure, through a three-stage synergistic mechanism of graphite inner core conductive supporting, porous carbon layer expansion buffering and nanometer silicon capacity contribution, the cycling stability of the negative electrode material is remarkably improved while the high specific capacity is maintained.

The invention discloses a silicon-carbon material as well as a preparation method and application thereof. The silicon-carbon material comprises nitrogen-doped porous carbon and an amorphous carbon layer coating the nitrogen-doped porous carbon, and pores of the nitrogen-doped porous carbon are filled with boron-doped nano silicon. The nitrogen-doped porous carbon improves the affinity of silane gas while improving the electron conductivity, a high-conductivity and high-density silicon-carbon composite structure is realized, the boron-doped nano silicon and the nitrogen-doped porous carbon form a nano heterojunction site, and the migration rate of lithium ions is improved, so that electrochemical reaction kinetics is improved, and the electrochemical performance of the lithium ion battery is improved. The material has the advantages of high rate and long cycle performance.

A silicon-carbon composite material and a preparation method therefor, a negative electrode sheet, a secondary battery, and a device. The silicon-carbon composite material comprises a carbon matrix having a pore structure and a silicon-based material distributed in the pore structure of the carbon matrix, and the silicon-carbon composite material contains the element phosphorus. The silicon-based material in the silicon-carbon composite material increases the capacity of the carbon matrix, and the carbon matrix having the pore structure improves the conductivity of the silicon-based material, and can also be used as a buffer medium for volume expansion of the silicon-based material during charging and discharging, so that the problem of increase of the volume of a secondary battery due to silicon expansion is effectively relieved; in addition, the element phosphorus doped in the framework of the carbon matrix is beneficial to improving the electronic conductivity of the material, thus improving the cycle performance of the battery.

The invention discloses a composite coated silicon-carbon negative electrode material as well as a preparation method and application thereof, and relates to the technical field of lithium ion batteries. The method comprises the following steps of: oxidizing and etching graphite in mixed gas of air and nitrogen at the temperature of between 400 and 500 DEG C to form graphite oxide; the preparation method comprises the following steps: dispersing water-soluble asphalt, graphene, nano silicon, melamine and monoammonium phosphate in water to form a composite liquid; and then mixing the composite liquid with graphite oxide, and then carrying out carbonization treatment. The high-performance silicon-carbon composite negative electrode material is prepared through graphite oxidation etching and a composite coating process, nano silicon is uniformly dispersed in carbon pores which are stably combined on the surface of graphite and have rich mesoporous structures, graphene and a nitrogen-doped carbon layer form a three-dimensional conductive network, and the composite negative electrode material is applied to lithium ion batteries and can be applied to lithium ion batteries. And the lithium ion battery has good low-temperature charging proportion, first efficiency and cycle performance.

The invention relates to the technical field of lithium ion battery negative electrode materials, and discloses a preparation method and application of a high-efficiency silicon-carbon composite graphite material, and the preparation method comprises the following steps: S1, carrying out porosity and size regulation and control on silicon particles: carrying out ball milling on industrial-grade silicon powder to obtain nano silicon particles, and carrying out acid etching to form a porous structure; s2, functional surface treatment and interface optimization: introducing functional molecules to the surfaces of the silicon particles and coating a layer of ultrathin SiO2 protective film; and S3, carbon coating and flexible protection layer construction: performing pyrolysis on the porous silicon particles by using a carbon source to form a uniform carbon coating layer which is applied to a lithium ion battery negative electrode material, and the lithium ion battery is used for an electric vehicle, a power grid energy storage system and portable electronic equipment. Through the collaborative design of the flexible protection layer, the double-layer carbon coating and the gradient coating, the technical bottlenecks of the silicon-based negative electrode material in the aspects of long cycle stability, high rate performance and interface chemical stability are systematically solved.

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 lithium battery materials, and particularly discloses an in-situ deposition coated phosphorus-carbon negative electrode material and a preparation method and application thereof.The in-situ deposition coated phosphorus-carbon negative electrode material comprises an inner core and an in-situ deposition layer coating the inner core in an in-situ deposition mode, the inner core is porous carbon deposited with red phosphorus, and the in-situ deposition layer is coated with the in-situ deposition layer in an in-situ deposition mode. The structural formula of the in-situ deposition layer is Ag < 1-x > Cd < x > S or Zn < 1-x > Cd < x > S, wherein x is more than 0 and less than 0.3. According to the in-situ deposition coated phosphorus-carbon negative electrode material provided by the invention, Ag < 1-x > CdxS or Zn < 1-x > CdxS is used for carrying out in-situ deposition coating on the phosphorus-carbon material, and uniform coating can be realized at a relatively low temperature, so that direct contact between red phosphorus and an electrolyte is effectively avoided, the conductivity of the material can be improved, and the capacity attenuation of the phosphorus-carbon composite material in a circulating process can be inhibited.

The invention belongs to the technical field of electrochemical energy storage, and discloses a composite bipolar plate for a zinc-bromine flow battery and a preparation method thereof.The preparation method comprises the steps that carbon fibers, ketjen black and graphene dispersion liquid are stirred to be uniform, and a conductive carbon composite material is obtained; a binder, a dispersing agent and the conductive carbon composite material are subjected to ball milling, and a bipolar plate prefabricated material is obtained; carrying out melt blending on the bipolar plate prefabricated material, and extruding to obtain a substrate; and spraying the nitrogen-doped porous carbon material on the surface of a substrate, and performing hot pressing. The graphene, the carbon fibers and the ketjen black are stirred and compounded, the carbon fibers and the ketjen black enter the space between graphene sheet layers, and the ketjen black is attached to the surfaces of the carbon fibers and the graphene, so that the structure not only can prevent the graphene from generating a re-stacking effect in the mixing process, but also can form a'point-line-surface 'ternary interpenetrating high-conductivity network, so that the conductivity of the graphene is improved. According to the preparation method disclosed by the invention, the deposition uniformity of zinc is improved, so that the voltage efficiency and the cycling stability of the battery are improved.

The invention discloses a silicon-carbon composite material and a preparation method thereof. The composite material is composed of porous hard carbon, inorganic lithium salt doped with the porous hard carbon and a porous metal frame as a matrix, nano silicon deposited in pores of the matrix, and an amorphous carbon composite material coated on the surface. The preparation method comprises the following steps: uniformly mixing resin, inorganic lithium salt and a porous metal framework, and carrying out hydrothermal reaction, activation and secondary carbonization to obtain a porous carbon complex; and depositing nano silicon and coating the nano silicon with an organic lithium salt through a vapor deposition method to obtain the silicon-carbon composite material. According to the obtained material, expansion is reduced through large-aperture deposited nanometer silicon of the metal frame structure, the defects are reduced through the inorganic lithium salt of the inner core and the organic lithium salt of the outer shell, the ion diffusion rate is increased, and the first efficiency and the rate performance are improved.

The invention provides a silicon-carbon negative electrode material and a preparation method thereof, a negative electrode and a lithium ion battery, and particularly relates to the technical field of negative electrode materials, the silicon-carbon negative electrode material comprises a porous carbon substrate, a silicon-containing substance and a phosphorosilicate glass coating layer, the silicon-containing substance is loaded in pore channels of the porous carbon substrate and forms a silicon-carbon compound, and the phosphorosilicate glass coating layer is coated with the silicon-carbon compound. The surface of the silicon-carbon compound is coated with the phosphorosilicate glass coating layer, phosphorus elements entering the silicon-carbon compound through thermal diffusion doping are arranged in the silicon-carbon compound, and a phosphorus-doped region is formed. The phosphorosilicate glass coating layer improves the strength of the silicon-carbon negative electrode and inhibits the volume expansion of the silicon-carbon negative electrode material. Meanwhile, the electrical property of the silicon-carbon negative electrode is improved through phosphorus doping, the structural stability and the electrochemical performance of the silicon-carbon negative electrode are improved, and the cycle life is prolonged.