182results about How to "Alleviate the volume expansion effect" patented technology

The invention relates to a SiOx-based composite material, a preparation method and a lithium ion battery. The SiOx-based composite material comprises a SiOx/C material, wherein the SiOx/C material comprises SiOx nano particles, organism cracked carbon, nano conductive particles and amorphous conductive carbon layers, the SiOx nano particles, the organism cracked carbon and the nano conductive particles are wrapped in the amorphous conductive carbon layers, the SiOx/C material is in a spherical shape and comprises a porous structure, and x is more than or equal to 0.5 and less than or equal to 1.3. The composite material is used as a negative electrode material of the lithium ion battery, excellent in cycling performance, excellent in rate performance and low in size expansion effect, applicable to the fields such as top-grade digital electrons, electric tools and next-generation vehicle-mounted devices and wide in market prospect.

The invention relates to a hollow silicon-based composite material, a preparation method and a lithium ion battery. The hollow silicon-based composite material disclosed by the invention comprises hollow cavities, a carbon-silicon composite layer and a cladding carbon layer in sequence from inside to outside, wherein the carbon-silicon composite layer comprises a secondary particle silicon layer and a deposited carbon layer. The preparation method comprises the following steps: firstly bonding silicon oxide and/or silicon on the surface of graphite uniformly, then removing the graphite through oxidizing heat treatment to obtain a hollow structure, then obtaining nanometer silicon through reduction by using a reducing agent, obtaining hollow particles consisting of the hollow cavities and the secondary particle silicon layer, then carrying out in-situ cladding on the surface of the secondary particle silicon layer, and then finally carrying out cladding of the cladding carbon layer to obtain the hollow silicon-based composite material. The battery prepared by using the composite material as an anode material has high cycle performance and rate capability, the first-time reversible capacity is more than 1453.2 mAh/g, the first-time coulomb efficiency is more than 87.8%, and the hundred-time cycle capacity retention ratio is more than 95.2%.

The invention discloses a spherical silicon-oxygen-carbon negative electrode composite material, which is of a three-layer structure comprising an inner layer, an intermediate layer and an outer layer, wherein the inner layer is an SiOx/graphite substrate; the intermediate layer is an amorphous carbon coating layer; the outer layer is a carbon nanotube coating layer; the mass of the inner layer SiOx/graphite substrate accounts for 80%-90% of total mass of the spherical silicon-oxygen-carbon negative electrode composite material; the mass of the intermediate layer amorphous carbon accounts for 5%-10% of total mass of the spherical silicon-oxygen-carbon negative electrode composite material; and the outer layer carbon nanotube accounts for 5%-10% of total mass of the spherical silicon-oxygen-carbon negative electrode composite material. The grain diameter of the adopted SiOx substrate is smaller than 5 microns; the grain diameter is relatively small; intercalation and deintercalation of active substances are facilitated; higher specific capacity can be obtained; meanwhile, a dispersing agent is added when an SiOx sample is ground; and condition that the SiOx with a relatively small grain diameter is agglomerated in quantity to affect the performance is prevented.

The invention relates to a flake MoS2/graphene composite aerogel and a preparation method thereof and belongs to the technical field of anode materials of lithium ion batteries. The preparation method comprises the following steps: ultrasonically dispersing a certain quantity of graphene oxide solution into deionized water, adding a certain quantity of water-soluble molybdate and thiourea, then adding 0.1-3mL organic amine solution, taking out a cylindrical product after hydrothermal reaction at the temperature of 160-240 DEG C, freeze-drying, and then carrying out thermal treatment for 2h in the mixed atmosphere of argon and hydrogen at the temperature of 800 DEG C to obtain the flake MoS2/graphene composite aerogel. According to the flake MoS2/graphene composite aerogel and the preparation method thereof disclosed by the invention, thin layers of graphene are connected with one another in a staggering mode to form a three-dimensional ordered conductive network and form micron pore canals, MoS2 is uniformly dispersed on the ultra-large superficial area, and thus, the problems of volume expansion and crushing materials are effectively solved; meanwhile, the structure stability and the cycle performance of the flake MoS2/graphene composite aerogel, serving as the anode material, are improved.

The invention provides a high-performance silicon/carbon anode nanocomposite and a preparation method thereof. The high-performance silicon/carbon anode nanocomposite is characterized by containing carbon nano-spherical particles with mesoporous channels, and the spherical particles and/or the mesoporous channels are filled with elementary silicon particles. The prepared silicon/carbon anode nanocomposite is of a porous structure, the elementary silicon particles are dispersed in a carbon skeleton and the mesoporous channels, the volume expansion effect during lithium-ion charge and dischargeis low, and electrochemical cycle performance is stable.

The invention discloses a lithium battery silicon-carbon nanotube composite cathode material as well as a preparation method and application of the lithium battery silicon-carbon nanotube composite cathode material. The preparation method of the lithium battery silicon-carbon nanotube composite cathode material comprises the following steps of: mixing and uniformly stirring an organic carbon source and nanometer silicon based on the mass ratio of (0.4-9): 1, adding a catalyst to obtain mixed slurry, drying by a closed circulation spray dryer to obtain a precursor, insulating the precursor for 1-5 hours at the temperature of 300-700 DEG C to obtain a sample, feeding the sample in a tube furnace, increasing the temperature to 500-900 DEG C under the mixed gas of gaseous organic carbon source and N2 and Ar2, and naturally cooling to obtain the lithium battery silicon-carbon nanotube composite cathode material. The lithium battery silicon-carbon nanotube composite cathode material has excellent electrochemical properties, high first charge-discharge efficiency up to more than 2000mAh/g, reversible specific capacity of about 1100mAh/g after cycle of 50 weeks, and good specific capacity and cycle performance, and the problems of low first efficiency, large irreversible capacity loss and poor conductivity of silicon when being used to prepare a lithium ion battery cathode are successfully solved.

The invention proposes a lithium ion battery negative electrode active material, a preparation method thereof, a negative electrode and a lithium ion battery comprising the negative electrode. The negative electrode active material is of a core-shell structure, wherein the core comprises lithium silicon alloy particles, and the shell is a carbon layer. In the negative electrode active material employing the core-shell structure of which the core is the lithium silicon alloy particles and the shell is the carbon layer, the volume expansion effect of silicon used as the negative electrode can be effectively reduced; and when the negative electrode is applied to the battery, relatively high capacity of the obtained battery can be maintained, and meanwhile, the battery also has good cycle property.

The invention discloses a preparation method of a porous long-circulation silicon carbon negative electrode material. The preparation method comprises the following steps of (1) performing ball milling on silicon monoxide until the obtained material is in nano scale; (2) coating the nanometer silicon monoxide with a carbon source in a liquid phase coating manner, and next, drying into powder; (3)putting the powder obtained in the step (2) into an atmosphere furnace to be subjected to carbonization treatment to obtain precursor powder; (4) performing secondary liquid phase coating on the precursor powder obtained in the step (3) and the carbon source and a conductive agent, and then drying into powder; (5) putting the powder obtained in the step (4) into an atmosphere furnace to be subjected to carbonization treatment again; and (6) putting the powder obtained in the step (5) into hydrofluoric acid to be soaked, and then performing filtering and washing by distilling water until the solution is neutral, and performing drying at a temperature of 90-150 DEG C to obtain powder to obtain the porous long-circulation silicon carbon negative electrode material. By virtue of the preparation method, the initial Coulomb effect and the cycle performance of the negative electrode material can be improved effectively, and meanwhile, simple process, environmental protection property, and facilitation of scale production can be realized.

The invention discloses a lithium ion battery graphite anode material and a preparation method thereof. The preparation method includes the steps of: 1) heating and kneading a mixture of natural graphite and an adhesive; 2) performing hot isostatic pressing moulding at 500-1000 DEG C under 50-100 MPa; 3) performing carbonization; 4) performing graphitization; and 5) crushing and classifying a product. The lithium ion battery graphite anode material has high tap density, large discharge capacity and good cycle performance, is reduced in internal pores of graphite particles, reduces expansion and is improved in cycle performance.

The invention discloses a method for preparing a composite cathode material of a silicon-carbon nanotube of a lithium ion battery. According to the method, firstly, the surface of nano silicon is coated with a carbon source, carbon nanotubes are generated in microwave treatment, and furthermore the surface of silicon is also coated with an introduced catalyst, so that the carbon nanotubes which are coated with the carbon source and are generated through catalytic cracking are very uniformly distributed on the surface of nano silicon, the problems that in the prior art the nano silicon is high in volume expansion effect, low in first charge/discharge efficiency and poor in circulation stability are solved, and both the conductivity and the mechanical property of the composite cathode material prepared by using the method disclosed by the invention are greatly improved and the circulation property, the multiplying power charge and discharge performance and the initial charge-discharge efficiency of the composite cathode material as a lithium lion battery cathode material are all greatly improved when being compared with those of a silicon-carbon nanotube cathode material which is mixed in a mechanical ball-milling manner as silicon and carbon nanotubes are compounded in an in-situ manner in the method disclosed by the invention. In addition, the method disclosed by the invention is simple in process, and the energy consumption is greatly reduced due to the adoption of a simple and efficient microwave chemical method.

The invention discloses a lithium ion battery negative nanometer material SnO2/MCMB (Mesophase Carbon Micro Beads) shell, and a preparation method and application of the shell. The SnO2/MCMB shell is prepared by reacting reactants in a mixed solution of deionized water and absolute ethyl alcohol at the volume ratio of 1:1 for 24-48 hours at 160-200 DEG C. By controlling the ratio, the reaction temperature and the reaction time of the reaction solvents, the structure, the size and the feature of the product are improved, the material performance is improved, and the first charge-discharge efficiency, the specific capacity and the cycle performance of the SnO2/MCMB shell are improved. A shell structure is adopted, the cycle stability of carbon and an effect of alleviating volume expansion of tin-based oxide with rod-shaped nanometer SnO2 are effectively combined, and the problems that tin-based oxide is low in first efficiency, large in irreversible capacity loss and poor in conductivity performance when tin-based oxide is used for preparing a lithium ion battery negative material are solved. The preparation method is simple in preparation technology and low in cost, and can be applied to industrial production.

The invention discloses a Co2SnO4/C nano-composite negative electrode material for a lithium ion battery, preparation and application of the Co2SnO4/C nano-composite negative electrode material. The method comprises the steps of dissolving tin salt and cobalt salt into a dispersing agent to obtain dispersion liquid; dropwise adding sodium hydroxide solutions into the dispersion liquid under the stirring condition; reacting, filtering or centrifuging and drying in vacuum to obtain powder; spreading the powder under the inert gas environment, raising the temperature to 900 DEG C, and then reacting to obtain a reaction product; mechanically milling the reaction product and graphite in a period of time and carrying out nano-milling again; finally, centrifuging the obtained solution to obtain a precipitate; washing and drying to obtain the Co2SnO4/C nano-composite negative electrode material for the lithium ion battery. According to the Co2SnO4/C nano-composite negative electrode material for the lithium ion battery, by adopting a form of doping the material and amorphous carbon, the material has the advantages of high charging/discharging efficiency for the first time, high specific capacity and high cycling stability.

The invention belongs to the field of lithium-ion battery anode materials, and provides a lithium-ion battery silicon-carbon composite anode material and a preparation method thereof. The lithium-ion battery silicon-carbon composite anode material comprises a core-shell structure and is characterized in that a core comprises nano silicon/graphene sheets and soft carbon, and the core is the nano silicon/graphene sheets and soft carbon composite particles which are obtained by performing heat treatment on a soft carbon precursor and the nano silicon/graphene sheets, the soft carbon is attached to the surfaces of the nano silicon/graphene sheets, and free spaces are formed among the nanometer silicon/graphene sheets; the shell is composed of a second carbon material and nano carbon which are coated on the surface of the core sequentially.

The invention belongs to the field of lithium ion batteries, and discloses a nanoparticle-compounded ZIF-8 negative electrode material of high specific capacity bismuth as well as a preparation methodand application of the nanoparticle-compounded ZIF-8 negative electrode material. The environment in a methanol solution is utilized to enable zinc ions (Zn<2+>) in zinc nitrate hexahydrate to cooperate with a 2-methylimidazole ligand to form a ZIF-8 precursor, after the precursor is subjected to high-temperature carbonization treatment in an inert gas shielding atmosphere of nitrogen gas, Zn<2+>is reduced by pyrolytic carbon in the ZIF-8 to zinc elementary substance (Zn) to form Zn@NC, finally, Bi replaces Zn in situ through simple replacement reaction (Bi<3+> plus Zn arrow Bi plus Zn<2+>)so as to obtain Bi@NC finally. The obtained Bi@NC greatly improves the conductivity of Bi, is conducive to reduction of internal resistance and transmission of electrons, and improves the performanceof reaction kinetics; meanwhile, the volume expansion of Bi@NC in the charging and discharging processes is eased, and the reversible specific capacity and cyclic stability of Bi@NC are improved.

The invention discloses a preparation method of a lithium ion battery silicon oxide composite negative electrode material, the method includes the following steps: (1) weighting a certain amount of silicon oxide SiOx, organic carbon and a graphite oxide precursor raw material for ball milling for 0.5-24 h to fully mix the precursor raw material; and (2) calcining the mixed precursor raw material in a protective atmosphere at 600-1400 DEG C for 0.5-12 h, and performing post-processing to obtain the silicon oxide composite negative electrode material. Through silicon oxide disproportionation, silica nanoparticles are distributed evenly in silicon dioxide, by organic carbon splitting decomposition, carbon coating is obtained, the probability of the formation of a SEI (solid electrolyte interphase) film in the material charge and discharge process can be reduced, the material electrochemical cycle stability can be improved, and by addition of graphite, good conductivity and ratio stability performance can be provided for the material. The production process is simple, raw material is cheap and easy to obtain, equipment is general, and mass production is easy.

The invention relates to a porous multi-element alloy compound anode material, a preparation method and a lithium ion battery containing the compound anode material. The multi-element alloy compound anode material provided by the invention comprises modified nanometer active materials, graphene chips dispersed between the modified nanometer active materials and amorphous conductive carbon layers wrapped on the modified nanometer active materials and the graphene chips. The lithium ion battery prepared from the compound material provided by the invention has excellent circulating and rate capabilities, lower volume expansion effect and potential market application prospect. The preparation technology according to the invention is simple, controllable and suitable for industrial production.

The invention provides a preparation method of Co3O4/nitrogen doped graphene composite electrode material. The preparation method comprises the following steps that step 1. nitrogen doped graphene is prepared; step 2. a soluble alkaline solution is prepared; step 3. polyacrylamide (PAM), heptahydrated cobalt sulfate and nitrogen doped graphene prepared in the step 1 are ultrasonic-dispersed in deionized water so that mixed liquid A is obtained; step 4. the soluble alkaline solution prepared in the step 2 is dropped in the mixed liquid A to react, and pH=8.5-10 is obtained through adjustment so that mixed liquid B is obtained; and step 5. the mixed liquid B is transferred to a microwave reactor to perform heating reaction, and suction filtration, washing and drying are performed on the product after the end of reactor so that the Co3O4/nitrogen doped graphene composite electrode material is obtained finally. The prepared composite material is stable in structure, and the method has advantages that the method is simple and environment-friendly, the reaction conditions are moderate, reaction is easy to control, cost is low and the technology and the process are simple and convenient.

The invention discloses a preparation method for a silicon carbon composite material for a lithium ion battery negative electrode. The method comprises the following steps: primary ball milling: a step of adding a grinding aid into elementary silicon for ball milling; and secondary ball milling: a step of mixing silicon powder obtained after primary ball milling with carbon powder and adding a grinding aid for ball milling again. The mass content of the carbon powder is 20 to 80%. A discharge gas medium employed in the dielectric barrier discharge plasma assisted high-energy ball milling method is inert gas. According to the invention, silicon in the composite material prepared in the invention can be finely and uniformly distributed on a carbon matrix, effective refining of silicon can be carried out on the basis that the integrity of graphite sheets is ensured, reversible capacity of a battery is improved, the problems of volume expansion and poor conductivity of a silicon-based electrode are alleviated, and comprehensive performance of the lithium ion battery is improved.