121results about How to "Improve high rate charge and discharge performance" patented technology

The invention provides a grapheme-coated sulfur/porous carbon composite material and a preparation method thereof, and relates to a grapheme-coated sulfur/porous carbon composite material used as the positive electrode material of a lithium-sulfur secondary battery and a preparation method thereof. The grapheme-coated sulfur/porous carbon composite positive electrode material provided by the invention can be used for solving the technical problem that the existing grapheme-coated sulfur-containing composite material used as the positive electrode material of a lithium-sulfur battery is low in electrochemical properties. The external surface of each of the particles of the grapheme-coated sulfur/porous carbon composite material provided by the invention is evenly covered with a graphene sheet, and a graphene conductive network is formed between the particles; the obtained grapheme-coated sulfur/porous carbon composite material has a hierarchical core-shell structure. The preparation method of the grapheme-coated sulfur/porous carbon composite material is obtained by adding a sulfur/porous carbon composite material to graphene slurry which is stable for a long time and in which graphene sheets are highly dispersed in water for mixing and coating. The positive electrode material has high specific capacity, long cycle life and excellent high-rate performance. Besides, the grapheme-coated sulfur/porous carbon composite material can be used as the positive electrode material of a lithium secondary battery.

The invention relates to a lithium ion battery cathode material LiNixCoyM1-x-yO2 prepared from micron-sized single crystal particles and a preparation method thereof, wherein x is greater than 0 and is not more than 0.8, y is greater than 0 and is not more than 0.5, and M is one or two of Li, Mn, Al and Mg. The invention is characterized in that (1) composite oxide or hydroxide of transition metal nickel, transition metal cobalt and modified metal M is used as a raw material, the composite oxide or hydroxide is porous aggregate comprising nanocrystals, the average size of the aggregate is 2-50 micrometers, and the specific surface area of the aggregate is greater than 15m<2>/g (measured by BET method); (2) the composite metal oxide or hydroxide and lithium salts are milled in a ball mill, the micron-sized composite metal oxide or hydroxide is converted into nanocrystal particles to obtain a nano-sized mixed precursor of the composite metal oxide or hydroxide and the lithium salts, and the mixed precursor is sintered at uniform temperature to obtain the required lithium ion battery cathode material; and (3) the prepared lithium ion battery cathode material LiNixCoyM1-x-yO2 is basically prepared from micron-sized single crystal particles, and the average size of the single crystal particles is 2-20 micrometers. In addition, the product has excellent physical and electrochemical properties, such as ultra-low specific surface area, reasonable particle size distribution, good electrode processing properties, ultra-long cycle life, excellent rate capability, obvious high and low temperature cycling and storing properties and excellent safety; and the product can be widely used as a high-performance lithium ion battery cathode material. The invention provides the high-performance lithium ion battery cathode material and the preparation method thereof.

The invention provides a high-rate charge-discharge lithium-ion battery and a preparation method thereof. The anode active material of the lithium-ion battery is lithium manganate; the cathode active material is selected from one or more of mesocarbon microbeads, artificial graphite or natural graphite coated by mesophase pitch; a conductive agent is selected from one or more of conductive graphite, conductive carbon black, nano Ag, nano SiO2 or nano Al2O3. The preparation method of the lithium-ion battery comprises the preparation of the anode plate, the parathion of the cathode plate and the assembly of the battery. The lithium-ion battery has the advantages of high-rate charge-discharge performance, long cycle life, high capacity, safe use, environmental protection, low cost and the like. The preparation method has the advantage of simple and easy process operation, and is applicable to the mass production.

The invention relates to manganese department positive electrode material of a lithium secondary battery, which can combine with electrolyte solution or solid electrolyte, and negative electrode active material to form lithium secondary battery. Its characteristics are: the positive electrode material of lithium secondary battery is LiMn1-x-y NixMyO2(x is not less than 0.2 and not larger than 0.8, y is not less than 0 and not larger than 0.6, and x+y is not larger than 1.), M is chosen from Li, Mg, Co, Ni, Fe, Al, Cr. The manufacturing method for manganese department positive electrode material of the lithium secondary battery, includes preparation of usher containing Mn; decorate to the covering of usher particle containing Mn; mix with lithium salt and prepare particle; sintering and other steps. By decoration of the surface of particle to usher 6 of positive electrode containing Mn or active material itself, state of material or apparent condition of material can be changed and its capacity of powerful charge and discharge, cycle performance and thermal stability can be raised. The invention has notable advantages including low cost, capacity of powerful charge and discharge, super-long cycle performance, excellent safety, super-long circulation property and resistance to overcharge .

The invention discloses a preparation method of a lithium-ion battery with a conductive polymer coated positive electrode. The positive electrode sheet is a positive electrode slurry made of a positive electrode material, a conductive agent, a positive electrode binder, a conductive polymer or a conductive polymer monomer, and a solvent. The negative electrode sheet is composed of negative electrode material, thickener, negative electrode binder, and solvent mixed into negative electrode slurry and negative electrode current collector. The specific capacity of the battery is increased by 10-20% by adding a conductive polymer or a conductive polymer monomer to the slurry for coating. The invention effectively improves the performance of the prepared positive electrode material, and because the method is simple, the product cost is reduced, the process is simplified, and the method is suitable for large-scale production.

The invention relates to a micron single crystal modified normal spinel lithium manganate LiMn(2-z)MzO4 and a preparation method thereof, wherein z is more than or equal to 0 and is less than or equal to 0.5. The preparation method is characterized in that firstly, composite oxides of manganese and modified metal M are used as raw materials of preparation, the composite oxides are porous aggregates consisting of nanometer microcrystal, the average size of the aggregates is between 5 micrometers and 20 micrometers, and the specific surface of the composite oxides powder is more than 20m/g (measured by a BET method); secondly, the prepared modified lithium manganate material basically consists of micro regular octahedron single crystal, the average size of the single crystal granular is between 5 micrometers and 20 micrometers, the specific surface is lower and is less than 0.5m/g. In addition, the product has excellent physical and electrochemical properties, such as ultralow specific surface, reasonable granular size distribution, better electrode processing property and ultralong circulation service life, excellent multiplying power property, remarkable high-low temperature cycling and storage properties, and best safety, and can be widely used as the materials of an anode of the lithium ion battery, especially a power lithium ion battery.

The invention provides a hydrothermal preparation method of a graphene-coated sulfur/porous carbon composite material and relates to a preparation method of the graphene-coated sulfur/porous carbon composite material for a positive electrode material of a lithium-sulfur storage battery. The hydrothermal preparation method is used for solving the technical problem that the electrochemical property of the positive electrode material of an existing lithium-sulfur battery, namely a graphene-coated sulfur-containing composite material, is low. The hydrothermal preparation method comprises the steps of mixing and scattering the sulfur/porous carbon composite material with graphene slurry or oxidized graphene slurry, carrying out hydrothermal synthesis to prepare a hydrogel column, and drying to obtain the graphene-coated sulfur/porous carbon composite material. According to the graphene-coated sulfur/porous carbon composite material prepared by utilizing the hydrothermal preparation method, the outer surfaces of the graphene sheet layers are coated with sulfur/porous carbon composite material particles, a graphene conduction network is generated among the particles, and the obtained graphene-coated sulfur/porous carbon composite material is in a hierarchical core-shell structure; the positive electrode material has the high specific capacity, the long cycle life and the good rate capability; the composite positive electrode material can be used as a positive electrode material in a lithium secondary battery.

The invention provides a preparation method of composite graphite to overcome the problems that the composite graphite prepared by the method in the prior art is low in energy density, poor in high-rate charge and discharge properties and high in expansion rate in the charging and discharging processes. The preparation method comprises the following steps: (S1) providing ultrafine carbon powder, wherein the ultrafine carbon powder comprises green coke and/or mesophase carbon green microspheres; (S2) mixing the ultrafine carbon powder with a binder to obtain a mixture A, mixing the mixture A with a catalyst to obtain a mixture B, and then carrying out combined treatment on the mixture B to obtain a precursor; (S3) carrying out graphitizing treatment on the precursor to obtain a semi-finished product; and (S4) crushing, spheroidizing, wrapping and sieving the semi-finished product to obtain the composite graphite. Meanwhile, the invention further discloses the composite graphite prepared by the method and a lithium ion battery. The composite graphite provided by the invention is high in energy density, good in liquid absorption and retention properties, good in isotropic property, good in high-rate charge and discharge properties and low expansion rate in the charging and discharging processes.

The invention discloses a composite carbon cathode material for a lithium ion battery and a preparation method thereof, and relates to a cathode material for a lithium ion battery. The invention provides the composite carbon cathode material for the lithium ion battery and the preparation method thereof, wherein the composite carbon cathode material can reduce the influence of a solid electrolyte interface (SEI) film on the cyclical stability of the cathode material, partially prevent anode dissolved metal ions from being deposited on the surface of the cathode material to affect the cyclical performance of the cathode material and still provide high specific energy under the condition of high charging current. The composite carbon cathode material is provided with a nuclear shell layer structure of at least three layers, wherein the outer layer is a metal layer, an alloy layer or a carbon layer; the middle layer is a lithiated metal oxide layer or a metal oxide layer; and the inner layer is a carbon material layer. The preparation method comprises the following steps of: mixing and then drying a raw material for preparing a metal oxide and a carbon material; heating and sintering the dried raw materials under the protection of atmosphere to obtain a composite material of the lithiated metal oxide or metal oxide layer with nuclear shell structure and the carbon material; and plating a metal, alloy or carbon conductive layer with reversible mechanical ductility on the surface of the composite material to obtain a product.

The invention discloses a porous lithium ion battery separator with an interpenetrating polymer network structure, and a preparation method and an application for the porous lithium ion battery separator. The preparation method specifically comprises the steps of uniformly mixing polyvinylidene fluoride-hexafluoropropylene, (methyl) acrylate monomers, octavinyl octa-silsesquioxane cross-linking agent and pore-forming auxiliary in a proper solvent to form porous gel polymer film with the interpenetrating polymer network structure through free radical polymerization, wherein the ion conductivity of the polymer film at a temperature of 25 DEG C can reach 1.0*10<-3>S/cm, the tensile strength can reach 7MPa, and excellent dimensional stability is realized; and on the basis, carrying out post processing on the gel polymer film to obtain the porous separator. By adoption of the lithium ion battery separator provided by the invention, the ionic conductivity can be greatly improved, and the high rate charging-discharging performance can be also obviously enhanced as well, so that the porous lithium ion battery separator is high in application potential.

The invention provides a lithium ion secondary battery. The lithium ion battery comprises a battery shell, a pole core and an electrolyte, wherein the pole core and the electrolyte are accommodated inthe battery shell; the pole core comprises a positive pole, a negative pole and a diaphragm positioned between the positive pole and the negative pole; the positive pole comprises a current collectorand positive materials; the positive materials comprise positive active substances, a conductive agent and a binder; the binder is provided with conductive performance; and the diaphragm is a porouspolyimide film. The invention also provides a preparation method for the lithium ion secondary battery. Due to the adoption of a conductive polymer serving as the positive binder and polyimide servingas the battery diaphragm, the lithium ion secondary battery provided by the invention significantly increases the capacity and the cycle performance of the battery, and significantly improves the high-rate charge and discharge performance.

The invention discloses a composite cathode material for secondary aluminum batteries. The composite cathode material is formed by compounding microporous carbon spheres, sulfur and graphene, has good electric conductivity and is capable of effectively suppressing that polysulfide dissolves in electrolyte to cause the shuttle effect. The preparation method of the composite cathode material comprises the following steps: firstly compounding the microporous carbon spheres and the sulfur, and then cladding the outer layer of the composition with a graphene sheet layer. The preparation method is simple in process and low in cost, toxic raw materials are not used, environment friendliness is achieved, the energy density is high, the utilization ratio of the sulfur is high, and the rate capability and the cycle performance of the secondary aluminum batteries are improved greatly.

The invention discloses a carbon sulfur compound anode for a secondary battery. The anode is formed by compounding a carbon nanotube array, sulfur and graphene, is provided with a three-dimensional network conductive framework and is good in electrochemical performance. A preparation method of the anode comprises the following steps: compounding elemental sulfur in the carbon nanotube array at first and then wrapping an outer layer with few graphene sheet layers. The preparation method is simple in process, low in cost and environment-friendly due to nonuse of toxic raw materials; moreover, the compound anode does not need to be added with a conductive agent and a bonder, and is high in energy density and sulfur utilization rate, and the rate performance and the cycle performance of the secondary aluminum battery are greatly improved.

The invention relates to the field of lithium batteries, and discloses a boron doping modified hard carbon coating negative electrode material with high rate performance and a liquid phase preparationmethod thereof. A hard carbon carbon layer is formed on the surface of a negative electrode substrate after carbonization by a hard carbon carbon source, boron oxide is generated by decomposing a boron-oxygen compound at a high temperature, and a composite structure such as boron-carbon bond and boron-carbon-oxygen bond is formed on the surface of the negative electrode substrate at a high temperature. On the one hand, compared with other negative electrode materials, hard carbon has larger interlayer spacing and better rate charge-discharge performance. Through hard carbon coating, the highrate charge-discharge performance of negative electrode materials can be improved. On the other hand, by doping boron into the negative electrode material, the position of carbon atom in the crystal lattice of other negative electrode materials is replaced by boron atom, and the atomic radius of boron atom itself is larger than that of carbon atom, which leads to the increase of the interlayer spacing of the negative electrode material and the magnification performance of the material.

The invention discloses carbon-Cu6Sn5 alloy negative electrode materials and a preparation method thereof. The carbon-Cu6Sn5 alloy negative electrode materials and the preparation method thereof combine carbon nanometer tubes and graphene into electrodes and add a Cu-CNTs connecting layer between active materials and current collectors. Therefore, cyclic perforce of an alloy negative electrode is improved greatly. The carbon-Cu6Sn5 alloy negative electrode materials and the preparation method thereof use copper foils as the current collectors (electroplating substrates). The copper foils are plated by a Cu-CNTs composite plating and a composite plating of stannum-carbon nanometer tubes or stannum- graphene or stannum-carbon nanometer tubes- graphenes in sequence, wherein the thickness of the Cu-CNTs composite plating is 1-5 micrometers and the thickness of the composite plating of the stannum-carbon nanometer tubes or the stannum- graphene or the stannum-carbon nanometer tubes- graphene is 1-4 micrometers. The carbon-Cu6Sn5 alloy negative electrode materials can be obtained finally through thermal treatments. First specific discharge capacity of lithium ion battery alloy cathodes prepared by the method can achieve 613 m AH /g and specific capacity attenuation of the lithium ion battery alloy cathodes is only 4%-6% after 100 cycles. The carbon-Cu6Sn5 alloy negative electrode materials and the preparation method thereof are simple in technique, good in prepared alloy cathode performance and suitable for large-scale industrial production.

The invention discloses a carbon-coated nano lithium titanate composite material and a preparation method thereof. The preparation method comprises the following steps: 1, preparing nano lithium titanate, namely, respectively preparing micro emulsions of a lithium source and a titanium source, mixing the two types of micro emulsion, standing, centrifuging, alternatively washing with an organic solvent and water, drying, and performing high-temperature calcinations; 2, performing carbon coating on nano lithium titanate, namely, preparing a solution from an organic carbon source, adding lithium titanate granules prepared in the step 1 into the solution, performing ultrasonic dispersion, performing hydrothermal reaction, cooling after the reaction, alternatively washing with the organic solvent and water, filtering, and drying, thereby obtaining the carbon-coated nano lithium titanate composite material. Refining of lithium titanate can be achieved through a micro emulsion method, the solution can be prepared from the carbon source, and carbon coating of the nano lithium titanate can be achieved through hydrothermal reaction, so that a conductive carbon network which is uniform and dense in combination can be formed on the surface of lithium titanate, the conductivity and the large-power charge/discharge property of an electrode material are remarkably improved, and the carbon-coated nano lithium titanate composite material can be used for preparing lithium ion electric containers and lithium ion batteries.

The invention belongs to the technical field of electrode material of lithium ion battery. The method is characterized in that the method comprises the following steps: dissolving titanium-containing precursor in absolute ethyl alcohol solution to obtain A solution; dissolving lithium-containing precursor in absolute ethyl alcohol to obtain B solution; and dropping the B solution in the A solution to form gel. The gel is dried, grinded and placed in a muffle furnace after aging for sintering to obtain Li4+xTi5+yO12; 70 parts of Li4+xTi5+yO12 and 17-23 parts of conductive black by weight are weighed and mixed and then grinded into a powder mixture; the mixture is poured in N-methyl pyrrolidone solution dissolved with 7-13 parts of bonder poly vinylidene fluoride by weight after being dried; the solution is coated on copper foil on standing at room temperature; and after drying, the lithium titanate cathode piece is obtained. The lithium titanate cathode piece as a deposition substrate is arranged rightly above the silicon source of a deposition cavity for deposition. The application of the method obviously improves high-powered charging and discharging performances of battery, and the improving effect is not influenced by specific technology for lithium titanate preparation; and the adaptability is very obvious.

The invention provides a lithium iron phosphate composite cathode material and a preparation method thereof. A lithium iron phosphate material is wrapped by or doped with doping type graphene, wherein the wrapping amount or doping amount of doping type graphene is 6-10 wt%. By means of the technical scheme, after the lithium iron phosphate cathode material and doping type graphene are compounded, the electron conductivity of lithium iron phosphate is greatly improved; meanwhile, the lithium ion dispersion speed of the material is increased, and therefore the large-rate charging and discharging performance of lithium iron phosphate is improved, and the low-temperature charging and discharging performance of the material is improved; the material is simple in preparation process and suitable for industrial large-scale production.

Disclosed is a preparation method for a high-activity material. The preparation method comprises the following steps of weighing a lithium source, an iron source, a phosphorus source, a carbon source and an additive based on certain proportions, wherein the molar ratio of Li to Fe to P is 0.9-1.2 to 1 to 1, and the molar ratio of the additive to the lithium source is 0.001-0.05 to 1; adding the raw materials into an ultra-fine ball milling-grinder comprising a dispersing agent to be fully grinded to obtain uniformly dispersed slurry; conveying the slurry to a spray dryer to be subjected to drying and pelleting to obtain a lithium iron phosphate precursor; and performing sintering on the lithium iron phosphate precursor in an atmosphere furnace for one time, and cooling instantly, and then performing smashing and mechanical integrating to obtain a lithium iron phosphate product. The preparation method is simple in technological process, low in production cost and suitable for large-scale production.

The invention provides a preparation method of a lithium titanate material, the lithium titanate material, and a lithium ion battery. The preparation method comprises the steps that: a mixture containing a lithium source and a nickel source is subjected to primary ball milling; the mixture is calcined, such that a precursor is obtained; the precursor is mixed with a titanium source, and the mixture is subjected to secondary ball milling; and the mixture is calcined in an inert or reductive atmosphere, such that the lithium titanate material is obtained. With the method, the prepared lithium titanate material has excellent rate discharge performance, and is especially suitable to be applied in fields such as power batteries which require high-rate charging and discharging.

The invention relates to the technical field of batteries, and discloses a lithium ion battery. The lithium ion battery comprises a sealing device with a positive electrode and a negative electrode as well as a battery polar group which is arranged inside the sealing device, wherein the battery polar group comprises a positive plate, a negative plate and an insulation layer, and the positive plate and the negative plate are mutually coiled or laminated to form a flat structure; the insulation layer is arranged between the positive plate and the negative plate and used for separating the positive plate from the negative plate; on one end surface of the flat structure formed by coiling or laminating the positive plate and the negative plate, the positive plate is higher than the insulation layer, and the positive plate which is higher than the insulation layer is connected with the positive electrode on the sealing device through metal; on the other end surface of the flat structure formed by coiling or laminating the positive plate and the negative plate, the negative plate is higher than the insulation layer, and the negative plate which is higher than the insulation layer is connected with the negative electrode on the sealing device through the metal. The invention also discloses a preparation method of the lithium ion battery and a lithium-ion battery pack.