79results about How to "Buffer volume effect" patented technology

The invention discloses a silicon carbon composite material and a preparation method thereof. According to the preparation method, nano silicon powder particles are taken as a silicon substrate, a Si-C porous shell-core composite material is prepared, and the synergistic effect of silicon and carbon can be fully developed; the silicon material is high in electrochemical capacity, the carbon material is high in conductivity, and the flexible carbon material can be used for absorbing stress and buffering a volume effect of the silicon; meanwhile, the stable and firm shell-core structure can be used for maintaining the material stability; the porous structure can be used for increasing the contact structure of the silicon particles and an electrolyte and improving the compatibility of the silicon particles and the electrolyte; and the three-layer shell-core structure material is dispersed in a graphene material, the conductivity of the material can be further improved, and the capacity performance and the cycle life of an electrode material are improved.

The invention discloses a silicon-carbon composite material and a preparation method thereof, and a lithium ion battery. The preparation method comprises following steps: (1) coating a silica-based material with a transition layer to obtain the transition layer-coated silica-based material; (2) coating the transition layer-coated silica-based material with carbon to obtain a carbon-transition layer-silicon based composite material; and (3) removing the transition layer to obtain the silicon-carbon composite material. The silicon-based material is coated with the transition layer, the transition layer is coated with the carbon, and the transition layer between the silicon-based material and the carbon is removed, so that a plurality of pores are formed between the silicon-based material and the carbon of the silicon-carbon composite material. The size of the pores between the silicon-based material and the carbon can be controlled precisely by setting the thickness of the transition layer according to micro-volume expansion theoretical value of the silicon-based material when lithium is embedded, so that volume effect of the silicon-carbon composite material is reduced effectively, and cycling performance of the lithium ion battery is further enhanced. The carbon of the silicon-carbon composite material is capable of increasing conductivity and rate capability of the composite material.

The invention relates to a preparation method for a petal-shaped molybdenum disulfide hollow mesoporous carbon sphere by in-situ growth, and belongs to the technical field of nanometer material production. The preparation method comprises the steps of mixing ethanol, deionized water, ammonia water, tetraethyl orthosilicate, resorcinol and formaldehyde for reaction; drying a solid phase and performing calcination in argon; etching the solid phase with a sodium hydroxide solution to obtain the solid phase, and drying the solid phase to obtain the hollow mesoporous carbon nanometer sphere; mixingsodium molybdate dihydrate, thiourea and the hollow mesoporous carbon nanometer sphere for hydrothermal reaction, performing centrifugal washing after hydrothermal reaction, drying the solid phase, and performing high-temperature calcination under protection of argon atmosphere to obtain the petal-shaped molybdenum disulfide hollow mesoporous carbon sphere by in-situ growth. The preparation method has the advantages that the raw material is low in cost, the process is environmental-friendly, high yield is achieved, and the prepared petal-shaped molybdenum disulfide hollow mesoporous carbon sphere by in-situ growth can be used as a lithium ion battery electrode material, a photocatalytic material or an electrocatalytic material.

The invention discloses a preparation method of different morphologies of cobalt monoxide nanometers loaded with foam nickel. The preparation method comprises: placing sheet-like foam nickel in an ultrasonic washing machine, washing, placing the washed foam nickel in a drying box, and drying; dispersing cobalt chloride hexahydrate powder into a dispersion solvent added with urea, and magneticallystirring at a room temperature to form a suspension; transferring the suspension to a high-pressure hydrothermal reaction kettle, obliquely placing the dried sheet-like foam nickel into the high-pressure hydrothermal reaction kettle, sealing the high-pressure hydrothermal reaction kettle, placing the high-pressure hydrothermal reaction kettle into the drying box, carrying out thermal insulation for 15-18 h at a temperature of 160-200 DEG C, and naturally cooling to a room temperature; taking the foam nickel out of the high-pressure hydrothermal reaction kettle, placing into the ultrasonic washing machine, washing, placing into a vacuum drying box, and drying to obtain a precursor; and calcining the precursor for 3-4 h at a calcination temperature of 400-520 DEG C.

The invention relates to a preparation method of a carbon-coated tungsten sulfide hollow nanosphere with a shell layer with a sandwich structure, and belongs to the technical field of production of anano material. The preparation method comprises the steps of: mixing alcohol, deionized water, ammonium hydroxide, ethyl orthosilicate, resorcinol and formaldehyde to perform a reaction, obtaining a solid phase to dry, and after calcining in argon, etching by aqueous solution of sodium hydroxide to obtain a hollow mesoporous carbon nanosphere; and after dissolving tungsten chloride and thiourea solid in the deionized water, adding the hollow mesoporous carbon nanosphere, after carrying out ultrasonic dispersion, performing a hydrothermal reaction, and after obtaining a solid phase to dry, calcining in the argon so as to obtain the carbon-coated tungsten sulfide hollow nanosphere of which the shell layer has the sandwich structure. The preparation method disclosed by the invention has the characteristics of cheap process raw material, simple and environmental-friendly process, high yield and excellent performance; the prepared carbon-coated tungsten sulfide hollow nanosphere of which the shell layer has the sandwich structure can be applied as a lithium ion battery electrode material, a photocatalysis material or an electro-catalysis material.

The invention discloses a tin @ hollow mesoporous carbon sphere material with a yolk-egg shell structure and a preparation method of the tin @ hollow mesoporous carbon sphere material with the yolk-egg shell structure. The material has the yolk-egg shell structure of taking elemental tin nanospheres as a yolk and hollow mesoporous carbon spheres as an egg shell; and the preparation method comprises the steps of taking the hollow mesoporous carbon spheres as nanoreactors and growing SnO2 particles in the nanoreactors; and reducing the SnO2 particles into elemental Sn at high temperature and forming the yolk-egg shell structure by the elemental Sn and the hollow mesoporous carbon spheres. According to the tin @ hollow mesoporous carbon sphere material with the yolk-egg shell structure, elemental Sn spheres are confined into the hollow mesoporous carbon spheres, a negative electrode material does not fall off in charging and discharging processes due to the unique yolk-egg shell structure, buffer space is provided for volume expansion of tin alloying through internal cavities, furthermore, the conductivity and the ion transfer rate of the material are improved through the hollow mesoporous carbon spheres, and improvement of the electrochemical properties of the composite material is facilitated.

The invention discloses a preparation method and application of spherical tin sulfide consisting of nanorods, belonging to the technical field of lithium ion battery materials. The invention further provides a preparation method of a negative electrode material. The method comprises the following steps: uniformly mixing a sulfur source, a tin source and a surfactant; heating a mixed solution by using a hydro-thermal method; filtering and drying the product to obtain a lithium battery negative electrode material of the spherical tin sulfide consisting of nanorods. Compared with spherical tin sulfide consisting of nanosheets, the spherical tin sulfide consisting of nanorods has the advantages that the cycle performance is improved, the stability of nanorods is higher than that of nanosheets in a circulating process, the volume change of an electrode material is suppressed effectively, the capacity fading of the electrode material is slowed down, and the cycle life of a battery is prolonged effectively.

The invention discloses a carbon-silicon composite material and a preparation method of the carbon-silicon composite material as well as a lithium-ion battery comprising the composite material. The carbon-silicon composite material comprises an amorphous carbon inner core and a shell which is formed by dispersing nano silicon into a pyrolytic carbon layer. The method is simple and easy to operate, is environmental-friendly and is suitable for large-scale production; the prepared carbon-silicon composite material has a stable structure, the nano silicon has good dispersibility and the coated degree of the nano silicon is very high; the carbon-silicon composite material is used as a negative electrode material of the lithium-ion battery and has a very high lithium removing specific capacity, a good circulating performance and an excellent rapid charging property; the lithium removing specific capacity is 391.7mAh/g or more, the capacity retention rate is 95.3 percent or more after the lithium-ion battery is charged and discharged at constant current of 1.0C for 50 times, and the charging rate of 10min can reach 90.2 percent.

The invention provides a preparation method for a tin-carbon composite negative material. An outer layer of the tin-carbon composite negative material is a composite cladding layer jointly formed by asphalt, resin and tin powder, and an inner layer is the tin-carbon composite negative material which is composed of graphite and has a core-shell structure. In the tin-carbon composite material prepared according to the method, high specific capacity characteristic of tin is maintained, meanwhile, a modification effect on the graphite is played, the overall cyclic stability of the material is improved, the energy density of the negative material of a lithium ion battery is improved, thus, the negative material has higher specific capacity than the carbon negative material commonly used in the lithium ion battery in the current market, and the increasing energy density requirement of various portable electric devices on the battery is met.

The invention provides a SnS/Ti02/rGO composite material for a potassium-ion battery negative electrode, a preparation method thereof and a matching electrolyte. In the SnS/Ti02/rGO composite material, the SnS has a mass fraction of 80% or more, and the Ti02 has a mass fraction of 2% or less. The microstructure of the SnS/Ti02/rGO composite material is that TiS-coated SnS nanoparticles are uniformly distributed on a reduced graphene oxide substrate, and have a particle size of 10-100 nm. The invention also provides a method for preparing the composite material and a matching electrolyte. The TiO2 coating has a protective effect on the SnS nanoparticles, and reduces the negative impact of the coating on material dynamics, provides the material with better electrochemical performance, and further improves the cyclic stable performance of the potassium-ion battery using the material through the optimization of the electrolyte.

The invention discloses preparation of an antimony pentoxide/silicon dioxide/carbon cloth flexible material and an application thereof as a negative electrode of a sodium-ion battery, which comprisesthe following steps: grinding silicon dioxide, adding the silicon dioxide into deionized water for dissolution to obtain a solution A; adding antimony trichloride into the ethanol solution for dissolution to obtain an antimony trichloride solution, and adding a sodium hydroxide aqueous solution into the antimony trichloride solution to adjust the pH value of the antimony trichloride solution to obtain a solution B; adding the solution A into the solution B and stirring to obtain a solution C; impregnating the activated carbon cloth in the solution C, transferring the solution C and the carboncloth into a reaction kettle for hydrothermal reaction, cooling the carbon cloth to room temperature, moving out the carbon cloth, and cleaning and drying the carbon cloth to obtain the antimony pentoxide/silicon dioxide/carbon cloth flexible sodium ion battery negative electrode material. The method is simple to operate and low in cost, and the silicon material can be applied to the negative electrode material of the sodium-ion battery.

The invention discloses a preparation method of tin-based cathode material of a high-capacity lithium-ion battery.The preparation method includes: mixing nano tin and graphite with a pyrolytic carbon organic matter precursor to obtain composite material precursor slurry, performing spraying drying to obtain precursor powder, calcining under inert atmosphere, and grinding to obtain nano tin/graphite composite material wrapped by organic matter pyrolytic carbon.By the preparation method, the dispersity of nano tin in the tin-carbon cathode material can be increased, the material stability during lithium getting off, high conductivity of the material is guaranteed, the pyrolytic carbon wrapping layer effectively wrap the surfaces of the particles of the material, the interface feature of the material can be improved effectively, and the electrochemical performance of the tin-carbon cathode material is increased.

The invention discloses a method for preparing a porous silicon/graphene composite lithium ion battery anode material by using diatomite as a raw material. The method is characterized by comprising the steps of diatomite purification, porous silicon preparation and porous silicon/graphene composite material preparation. The preparation method is scientific and reasonable, simple, convenient and practicable, low in cost, environmentally-friendly and high in practicability, raw materials are wide in sources, excellent conductivity and good mechanical performance of graphene are sufficiently utilized, the problems such as electrical conductivity and volume effect of a silica-based material are effectively improved, the method is directly used for the lithium ion battery anode material, and the reversible capacity still can reach 609.4 mAh/g after 100 times of cycle under the current density of 100 mA/g.

A method for prepare a self-supporting three-dimensional graphene/tin composite lithium ion battery negative electrode material relates to a preparation method of a lithium ion battery negative electrode material. The invention solves the technical problems of high mobility and poor multiplicity of the existing three-dimensional graphene and tin composite materials. 11) mix graphene oxide dispersion liquid and nanometer tin dioxide into a mixed liquid; Or mixing graphene oxide dispersion, nano tin dioxide and acidified carbon nanotubes into a mixed liquid; 2, dry after hydrothermal reaction toobtain an electrode precursor; 3, the precursor is reduced in H2/Ar mixed gas atmosphere at high temperature to obtain the material. The specific discharge capacity of the material of the first cycleat current density of 200mA g<-1> is 1089.4 mAh g<-1> - 1098.9 mAh g<-1>. The capacity retention rate was above 53.1% in the 100th cycle. The cycle performance is stable and it can be used as the material of lithium ion battery.

The invention provides a hollow porous cuprous oxide-copper oxide-ferric oxide cubic lithium ion battery anode based on three-dimensional porous copper skeleton in-situ growth. The battery anode is composed of a three-dimensional porous copper skeleton and hollow porous cuprous oxide-copper oxide-ferric oxide cubes, the hollow porous cuprous oxide-copper oxide-ferric oxide cubes are cubes which are of a hollow porous structure and is formed by assembling cuprous oxide nanoparticles and copper oxide nanoparticles, wherein the cuprous oxide nanoparticles and the copper oxide nanoparticles are formed by partially oxidizing the surfaces of ferric oxide nanoparticles and the three-dimensional porous copper skeleton in situ. The hollow porous cuprous oxide-copper oxide-ferric oxide cubes are uniformly distributed on the surface of the three-dimensional porous copper skeleton. The invention also provides a one-step preparation method of the anode. The lithium ion battery anode provided by theinvention can effectively buffer the volume change of the lithium ion battery in the charge-discharge process, prevent the active component from falling off in the charge-discharge process of the lithium ion battery, and significantly improve the specific capacity and cycle performance of the lithium ion battery anode.

The invention discloses a graphite flake /trimanganese tetroxide composite nano-material with a sandwich structure, its preparation method, and a lithium ion battery using it. The method comprises the following steps: weighing expanded graphite and DMF according to a ratio of 0.5-5g/L, putting the expanded graphite in the DMF, and carrying out ultrasonic treatment for 1-4h to obtain a graphite flake solution; adding deionized water according to a ratio of deionized water to the DMF of 1:1-1:9, and uniformly stirring; weighing manganese (II) acetate tetrahydrate according to a ratio of the manganese acetate tetrahydrate to the solvent DMF of 5-60g/L, dissolving the manganese acetate tetrahydrate in the solvent, and uniformly stirring; adding the above obtained solution into a hydrothermal tank, heating, carrying out heat insulation, and carrying out furnace cooling; cleaning a black sediment by using a centrifuge after the above obtained material is cooled to room temperature; and baking the cleaned black sediment at 50-80DEG C until the obtained sample is dry. The method for obtaining a uniform Mn3O4 nanoparticle film on the surface of a non-oxidized graphite flake is simple, and is suitable for mass production.

The invention discloses a preparation method for a modified graphite anode material. The preparation method comprises the following steps: (1) preparing a slurry precursor; (2) drying the precursor; (3) performing heat treatment. The prepared graphite anode material has higher specific capacity; the material is modified, so that the electrical conductivity of the material is effectively improved, and the cyclic stability of the material is improved; therefore, when the anode material is used for a lithium ion battery, higher energy density and good cyclic stability are achieved.

The present invention relates to a lithium ion battery anode material with high specific capacity and a preparation method thereof. The lithium ion battery anode material is a zinc sulfide-zinc selenide composite material based on a zinc sulfide hollow nanosphere structure. The preparation method comprises the steps of: preparing a zinc sulfide hollow nanosphere, and adding selenium powder, grinding and heating the mixture of the zinc sulfide hollow nanosphere and the selenium powder to perform selenylation of the surface of the zinc sulfide hollow nanosphere. The zinc sulfide is introduced asan anode material, and a zinc sulfide-zinc selenide composite material is obtained by employing a simple selenylation reaction. The lithium ion battery anode material has obvious structure advantages, can provide more oxidation active sites to obtain higher specific capacity, and has good mechanical properties and a good cycle life. The zinc sulfide and the zinc selenide are taken as anode material active materials, and the electrochemical properties of the lithium ion battery are improved through the synergistic effect of the zinc sulfide and the zinc selenide.

The invention relates to a sodium-ion battery negative electrode material compounded by a nickel oxide-nickel sulfide composite and graphene and a preparation method thereof. The composite material has a double-layer hollow sphere structure. The preparation process includes the following steps: firstly, preparing a nickel oxide double-layer hollow sphere, partially vulcanizing the hollow sphere toobtain the nickel oxide-nickel sulfide composite, and then compounding the nickel oxide-nickel sulfide composite with graphene to prepare the negative electrode material by using a spray drying method. The composite material of the invention can provide more oxidation active sites, obtains higher specific capacity under high current density, shortens the transmission path of electrons and charges, relieves the expansion of materials during charging and discharging, and achieves good cycle life due to good mechanical properties. According to the scheme of the invention, graphene and the nickeloxide-nickel sulfide hollow sphere are compounded, so that the conductivity of the negative electrode material can be enhanced, the volume expansion of active substances in the charging and discharging process can also be alleviated, and the electrochemical performance of the sodium-ion battery can be improved.