303 results about "Lithium titanate" patented technology

The invention provides a lithium supplement composite layer and a preparation method thereof, a lithium supplement method, a pre-lithiated negative pole piece, a secondary battery and an electronic device, the lithium supplement composite layer comprises an interface layer and a lithium supplement layer which are laminated, the interface layer comprises interface particles and a binder, the interface particles comprise a lithium intercalation material and / or a conductive agent, and the binder comprises a lithium intercalation material and / or a conductive agent. The lithium intercalation material is selected from at least one of artificial graphite, natural graphite, hard carbon, a silicon-carbon material, a silicon-oxygen material, lithium titanate, tin and a tin-copper alloy, and the conductive agent is selected from at least one of conductive carbon black, carbon fiber, graphene and a carbon nanotube; the binder is selected from at least one of polytetrafluoroethylene, an ethylene-tetrafluoroethylene copolymer, a tetrafluoroethylene-hexafluoropropylene copolymer, polyvinylidene fluoride and polyoxyethylene; the lithium supplementing layer comprises lithium metal and / or lithium alloy. The lithium supplement composite layer meets the above characteristics, lithium supplement is carried out on the negative pole piece, the first coulombic efficiency of the secondary battery can be improved, the cycle capacity attenuation is reduced, and the energy density of the secondary battery is improved.

The invention relates to a desolventizing layer modified silicon-carbon negative electrode and a preparation method, the desolventizing layer modified silicon-carbon negative electrode comprises a silicon-carbon negative electrode, the silicon-carbon negative electrode comprises porous carbon mainly comprising mesopores and a silicon substrate attached in the pores of the porous carbon, and the desolventizing layer is covered on the surface of the silicon-carbon negative electrode. The desolventizing layer is an oxide of an amorphous active metal and a composite oxide of the amorphous active metal and lithium, the desolventizing layer at least covers the surface of the silicon substrate in the pores of the porous carbon, the desolventizing layer is made of amorphous titanium oxide, lithium titanate, niobium oxide, lithium niobate and titanium niobate, and after the electrolyte permeates into the pores of the porous carbon, the surface of the silicon substrate is coated with the desolventizing layer. And the lithium ions subjected to desolvation through the desolvation layer are alloyed with a silicon substrate. And the structural stability, the charge-discharge efficiency and the rate capability of the silicon-carbon negative electrode material are improved.

The invention belongs to the technical field of lithium batteries, and particularly relates to a composite metal lithium material, a preparation method and application thereof and a composite metal lithium negative electrode. The composite metal lithium material comprises metal lithium, and lithium titanate and a carbon material which are dispersed in the metal lithium. The composite metal lithium negative electrode is prepared from the composite metal lithium material through hot pressing, lithium titanate and a carbon material serve as a lithium-loving supporting structure, the interface stability and the structural stability of the composite metal lithium negative electrode in the circulation process can be synergistically improved, and the advantage of high capacity of lithium metal is kept; and the problems of infinite volume change of the lithium metal negative electrode and uncontrollable growth of lithium dendrites are solved, so that the composite metal lithium negative electrode has excellent cycling stability. The preparation method of the composite metal lithium negative electrode has the advantages of being easy to operate and good in repeatability.

The invention provides a positive plate, a battery, a battery pack and electric equipment. The positive plate comprises a positive current collector, a first positive active layer and a second positive active layer, wherein the first positive active layer and the second positive active layer are stacked on at least one side of the positive current collector; the first positive electrode active layer comprises a first positive electrode active material, and the second positive electrode active material comprises a first positive electrode active material and a second positive electrode active material; the first positive electrode active material comprises at least one of a manganese-based positive electrode active material, an iron-based positive electrode active material and a manganese-iron mixed-based positive electrode active material, and the second positive electrode active material comprises at least one of a ternary positive electrode active material, lithium cobalt oxide, lithium nickelate and lithium titanate; the second positive electrode active layer further comprises a second conductive agent, and the second conductive agent comprises at least two linear conductive agents and at least one of a sheet-shaped conductive agent and a point-shaped conductive agent. The positive plate has a special structure and composition, and can effectively improve the impedance increase of the battery and improve the cycle performance of the battery.

The present invention belongs to the field of ion battery technology, specifically relating to silicon-based composite materials, their preparation methods and applications, lithium-ion batteries, and their negative electrode materials and negative electrode sheets. In the present invention, nano-silicon material and lithium titanate are ball-milled to obtain a ball-milled product; the mass of the lithium titanate accounts for 1-10% of the mass of the nano-silicon material, and the ball-milling speed is ≤500 rpm. ‑1 , for ≤10 h; and sintering the ball-milled product in a protective gas atmosphere to obtain the silicon-based composite material, wherein the sintering temperature is ≤500°C. The silicon-based composite material provided by the present invention is applied to lithium-ion batteries and exhibits significant initial discharge specific capacity, good rate performance, and excellent first coulombic efficiency. Furthermore, the preparation method is simple and environmentally friendly, making it suitable for large-scale industrial applications.

The present disclosure relates to a negative electrode and a secondary battery including the same, wherein safety against external short circuit is improved by increasing resistance in the battery.In an aspect of the present disclosure, the electrode includes:a current collector; anda plurality of negative electrode active material layers provided on at least one side of the current collector, whereinthe plurality of negative electrode active material layers includea first negative electrode active material layer including lithium titanium oxide (LTO) and carbon nanotube (CNT) andone or more second negative electrode active material layer including a negative electrode active material other than the lithium titanium oxide (LTO),the loading amount of the first negative electrode active material layer is 0.2 mAh / cm2 or less, andthe first negative electrode active material layer is in contact with the current collector or is located between the two or more second negative electrode active material layers.

The invention provides a negative electrode material, preparation thereof, a negative electrode plate, a secondary battery and a device, the negative electrode material comprises a silicon-based material, a first coating layer located on at least one part of the surface of the silicon-based material, and a second coating layer located on at least one part of the surface of the first coating layer, the first coating layer comprises amorphous carbon; the second coating layer comprises lithium titanate; and the number of particles of the silicon-based material in the first coating layer is 1-15. The negative electrode material disclosed by the invention has the core-shell structure, so that the cyclic expansion of the silicon-based material can be improved, different electrical property requirements can be met by different core-shell gap blending, and meanwhile, the mechanical strength in the needling process can be improved by coating the surface of the silicon-based material with lithium titanate, so that the electrical property of the silicon-based material can be improved. After lithium titanate is rapidly discharged to form Li4Ti5O12 under the condition of short circuit, the internal resistance is increased, and the generation of Joule heat is reduced, so that the mechanical safety performance can be obviously improved.

The invention relates to the field of lithium ion batteries, and discloses a lithium titanate composite material and a preparation method thereof, a negative pole piece and a preparation method thereof, a lithium battery and a battery pack. The surfaces of lithium titanate particles are sequentially coated with the nitrogen-doped carbon intermediate layer and the two-dimensional MXene material outer layer, and the MXene material outer layer is formed by bridging adjacent particles through hydrogen bonds, so that a'core-shell-bridge 'three-dimensional conductive network structure is constructed, the electronic conductivity of the lithium titanate composite material is remarkably improved, the electron / ion transmission efficiency of the lithium titanate negative electrode is improved, and the lithium titanate negative electrode has a good application prospect. The lithium ion battery has excellent rate capability and cycle performance; and through collaborative optimization of the three-dimensional composite material and the electrolyte, the interface impedance is reduced, and polarization is inhibited, so that the lithium battery still keeps high capacity and long cycle stability under ultrahigh rate, and meanwhile, the problems of discontinuous conductive network and high interface impedance in the prior art are solved. And excellent rate capability and cycle performance can be achieved under ultrahigh rate.

The invention discloses a battery negative electrode material and a preparation method thereof, and relates to the technical field of batteries. The battery negative electrode material comprises an inner core, a titanium dioxide coating layer coated on the surface of the inner core, a lithium titanate coating layer coated on the surface of the titanium dioxide coating layer, a carbon coating layer coated on the surface of the lithium titanate coating layer and a polymer coating layer coated on the surface of the carbon coating layer, the inner core comprises a silicon-based negative electrode material; the polymer coating layer comprises at least one of polyaniline, polythiophene and polypyrrole. Under the action of the four coating layers, the integrity of the silicon-based negative electrode material can be kept, direct contact between the silicon-based negative electrode material and an electrolyte is avoided, side reactions are reduced, the capacity fading of the battery in the charge-discharge cycle process is reduced, and the rate capability and the cycle stability of the battery are improved.

The invention provides a positive electrode material and a preparation method thereof, a positive electrode plate and a secondary battery, and belongs to the field of battery materials, the positive electrode material comprises an inner core and a composite coating layer coating the surface of the inner core; the inner core comprises lithium iron phosphate, and the composite coating layer comprises a carbon material and a metal oxide; wherein the metal oxide comprises at least one of lithium titanate, lithium manganate and lithium cobalt oxide. The carbon material and the metal oxide containing titanium, cobalt and manganese are compounded to serve as the composite coating layer to coat the lithium iron phosphate core, on one hand, the microstructure characteristics of the metal oxide containing titanium, cobalt and manganese are utilized, richer channels are provided for lithium ion diffusion, on the other hand, the high electron conductivity of the carbon material is utilized, and the lithium ion diffusion efficiency is improved. The prepared positive electrode material can simultaneously have relatively high electronic conductivity and lithium ion diffusion rate, and when the positive electrode material is used as a lithium ion battery, the charge-discharge performance and the cycle life of the lithium ion battery are remarkably improved.

The invention discloses a three-site co-doped lithium titanate carbon-coated material and a preparation method and application thereof.The lithium titanate carbon-coated material comprises a carbon-coated material, a lithium titanate material and anions and cations doped in the lithium titanate material, a titanium source is dissolved in a solution containing the carbon-coated material, a lithium source, a doped potassium source, an aluminum source and a fluorine source are added, and the mixture is stirred to be uniform; sequentially heating and stirring, drying, grinding and sintering at high temperature. According to the invention, lithium, titanium and oxygen sites in the lithium titanate material are replaced by co-doping trace potassium, aluminum and fluorine, so that the electronic conductivity of the surface of the material is effectively improved, the synergistic effect of doped anions and cations can induce and improve the internal characteristics of the material, and as the negative electrode material of the lithium ion battery, the cycling stability of the material in the organic lithium ion battery can be improved; and the device is high in safety and is used for energy storage equipment, backup power supplies, reserve power supplies and the like.

The invention discloses a preparation method of a low-loss temperature-stable lithium titanate-based microwave dielectric ceramic material and a product prepared thereof.Li2CO3, TiO2, Fe2O3 and Nb2O5 serve as raw materials, Ti < 4 + > is replaced with (Fe1 / 2Nb1 / 2) < 4 + >, the lithium titanate-based microwave dielectric ceramic material with the chemical formula being Li2Ti1-x (Fe1 / 2Nb1 / 2) xO3 is formed, the oxygen vacancy content caused by electrostatic compensation is remarkably reduced, and the temperature stability of the microwave dielectric ceramic material is improved. Therefore, the dielectric loss is reduced, the Q value of the microwave dielectric ceramic is improved, and meanwhile, the unit cell parameters can be changed to influence the dielectric constant temperature coefficient to adjust the TCF value, so that the dielectric property of the Li2TiO3-based microwave dielectric ceramic is effectively improved.

The present invention relates to a positive electrode active material for an all-solid-state battery, a positive electrode, and an all-solid-state battery comprising the same. More specifically, the positive electrode active material of the present invention has, on a surface thereof, a particle layer coated with lithium titanium oxide particles, in which the particle layer prevents a side reaction between the positive electrode active material and sulfide-based solid electrolyte particles in a positive electrode, thereby enabling an all-solid-state battery to be stably charged and discharged.

The invention discloses a niobium-titanium-silicon-carbon composite material, a preparation method and application thereof and a battery. The preparation method of the niobium-titanium-silicon-carbon composite material comprises the following steps: mixing porous niobium oxide, a silicon source and a solid electrolyte to obtain a silicon intermediate product; and granulating and screening the mixture of the silicon intermediate product, the nano-porous lithium titanate oxide and the carbon source to obtain the niobium-titanium-silicon-carbon composite material. The niobium-titanium-silicon-carbon composite material prepared by the invention shows excellent rate capability and cycle performance when being used as a battery negative electrode material, and the preparation method is simple.

The invention discloses a modified lithium titanate negative electrode material and a preparation method thereof, a negative electrode plate, a battery and an electric device, and belongs to the field of energy and the field of new materials. The preparation method of the modified lithium titanate negative electrode material comprises the following steps: carrying out first reaction on lithium salt and first glacial acetic acid in a first solvent to prepare a lithium acetate solution; zirconium salt and second glacial acetic acid are subjected to first mixing in a second solvent, and a zirconium salt solution is formed; performing second mixing on the lithium acetate solution and the zirconium salt solution to form a lithium-zirconium mixed solution; performing third mixing on the lithium-zirconium mixed solution and a titanium source to form lithium-titanium-zirconium sol; and drying and calcining the lithium-titanium-zirconium sol to form the modified lithium titanate negative electrode material. According to the preparation method, the zirconium element is adopted for doping, meanwhile, a homogeneous phase mixing reaction process is matched, and a high-energy grinding process is not needed, so that uniform mixing of the raw materials on the molecular level can be realized, the high-rate charge-discharge capacity and the first efficiency are improved, and the probability of gas production of the battery is reduced.

The invention discloses a solid electrolyte membrane of a bimetal MOFs composite lithium ion sieve and a preparation method and application of the solid electrolyte membrane. The preparation method of the electrolyte membrane comprises the following steps: dispersing a bimetallic MOFs material, a phenylphosphinic acid modified lithium titanate molecular sieve and a lithium salt in a solvent, adding a polymer material, and mixing and stirring to obtain mixed slurry; and pouring the mixed slurry into a container paved with a polytetrafluoroethylene film, and volatilizing the solvent to obtain the coating. The composite solid-state electrolyte membrane has good ionic conductivity, good toughness and good mechanical properties, and can improve the cycle performance and rate capability of a battery when applied to the solid-state battery. The preparation method is simple, low in cost and suitable for large-scale industrial production.

The invention is suitable for the technical field of lithium ion battery materials, and discloses a graphene-heteroatom doped porous carbon material, a lithium titanate amorphous carbon coated silicon carbon composite material, a preparation method thereof, a negative pole piece and a lithium ion battery. The graphene-heteroatom doped porous carbon material is prepared from porous carbon, graphene and heteroatoms, the graphene and the heteroatoms are distributed in the porous carbon, and in percentage by mass, the content of the graphene is 0.5 wt%-2wt%, the content of the heteroatoms is 0.5 wt%-2wt%, and the balance is the porous carbon. According to the graphene-heteroatom doped porous carbon material disclosed by the invention, the compaction density of porous carbon is improved by utilizing high electron conductivity of heteroatoms and high ductility of a graphene lamellar structure; in addition, a basic group on the surface of the heteroatom solution and an acidic group of the graphene oxide can generate a chemical bond linked carbon structure through a hydrothermal reaction, and the tap density and the electronic conductivity of the material are improved.

The invention discloses a high-energy-density fast-charging polymer soft package battery, which comprises a positive electrode, a negative electrode, a diaphragm, an electrolyte and a packaging body, the positive electrode is composed of core-shell composite particles prepared from lithium cobalt oxide and a lithium-rich manganese-based material through a spray drying method, the negative electrode is a lithium titanate coated three-dimensional porous graphene skeleton loaded silicon carbon composite material, and the lithium titanate coated three-dimensional porous graphene skeleton loaded silicon carbon composite material is a lithium titanate coated three-dimensional porous graphene skeleton loaded silicon carbon composite material. The electrolyte comprises lithium bis (trifluoromethylsulfonyl) imide, fluoroethylene carbonate and 1, 3-propane sultone, and the packaging body sequentially comprises a polyether-ether-ketone high-temperature-resistant layer, a nanometer aluminum oxide enhanced aluminum foil and a modified polypropylene heat sealing layer from inside to outside. Through modification of positive and negative electrode materials, optimization of an electrolyte and improvement of a packaging process, the energy density, the fast charging performance, the safety, the cycle life and other aspects are remarkably improved, and the defects of a traditional soft package battery are effectively overcome.

The invention discloses a lithium titanate battery, and relates to the technical field of batteries. The battery comprises a positive electrode, a negative electrode, an electrolyte and a diaphragm, and an addition product synthesized by dimethyl fumarate and benzidine according to a specific molar ratio is added into the electrolyte as a viscosity modifier, so that the viscosity increasing trend of the electrolyte at a low temperature is effectively reduced, and the migration rate of lithium ions is improved. And the electrolyte also comprises a lithium salt, an organic solvent and an auxiliary additive, so that the low-temperature performance and the cycling stability of the battery are favorably optimized. A positive active material is one or more of lithium iron phosphate, lithium manganate, lithium cobalt oxide or nickel manganese cobalt ternary materials, a negative active material is lithium titanate, and additives such as lithium nitrate and fluoroethylene carbonate are further combined, so that the capacity retention ratio and the charge-discharge efficiency of the battery in an extreme low-temperature environment of-40 DEG C are remarkably improved. The lithium titanate battery provided by the invention has excellent low-temperature adaptability, safety and long cycle life, and is applicable to power batteries and energy storage systems in alpine regions.

The invention discloses a negative pole piece and a secondary battery prepared from the negative pole piece, and belongs to the technical field of electrochemical energy storage, the negative pole piece takes a compound of silicon-based particles and graphite particles as an active material, and meanwhile, a coating layer containing lithium titanate is arranged on the surfaces of the graphite particles, so that the ionic crosstalk phenomenon of a traditional silicon-carbon negative pole is effectively avoided, the dynamic performance is excellent, and the service life is long. And ideal stability and fast charging performance can be realized when the lithium ion battery is applied to a secondary battery.

The invention relates to the technical field of batteries, in particular to a negative plate, a preparation method thereof and a battery. The negative plate comprises a current collector; the first negative electrode coating is arranged on the surface of at least one side of the current collector along the thickness direction, and the first negative electrode coating comprises a carbon-based material; the second negative electrode coating is arranged on the surface, far away from the current collector, of the first negative electrode coating, and the second negative electrode coating comprises a tin-based material; the third negative electrode coating is arranged on the surface, far away from the first negative electrode coating, of the second negative electrode coating, and the third negative electrode coating comprises modified lithium titanate. According to the invention, the problems of large volume expansion, large first irreversible capacity, poor cycle stability and the like after lithium ions are embedded into the current SnO2 negative electrode can be solved.

The invention discloses a method for preparing a carbon-coated lithium titanate negative electrode material by a one-step solid phase method, and belongs to the technical field of lithium ion battery materials. The method comprises the following steps: uniformly mixing and dispersing carbon-containing lithium salt, titanium salt and metal hydride to obtain a solid mixture; and roasting the obtained solid mixture in a protective atmosphere to obtain the carbon-coated lithium titanate negative electrode material. According to the preparation method, a certain amount of metal hydride is added into the reaction raw materials, a high-temperature solid-phase method is used, and carbon in the carbon-containing lithium source is reduced by the metal hydride to serve as a carbon source, so that the carbon-coated lithium titanate negative electrode material can be directly synthesized in one step, additional carbon sources and technological processes are not needed, and the preparation technology is greatly simplified.

The invention discloses a preparation method of a modified lithium titanate battery negative electrode material. The preparation method comprises the following steps: S1, weighing zirconium chloride and benzoic acid, dissolving the zirconium chloride and benzoic acid in N, N-dimethylformamide, and mixing to obtain a first solution; s2, weighing 2, 2 '-bipyridine-5, 5'-dicarboxylic acid formic acid, dissolving the 2, 2 '-bipyridine-5, 5'-dicarboxylic acid formic acid into N, N-dimethylformamide, and mixing to obtain a second solution; s3, adding the first solution into the second solution, uniformly mixing, and reacting to obtain a third solution; s4, the third solution is subjected to suction filtration, washing and drying, and powdery UiO-bpy is obtained; s5, weighing lithium titanate powder and UiO-bpy, dissolving the weighed lithium titanate powder and UiO-bpy in ethanol to obtain a fourth solution, and drying the fourth solution to obtain an intermediate sample; and S6, heating the intermediate sample in a tubular furnace under the protection of Ar atmosphere, and cooling to obtain the battery negative electrode material UiO-bpy (LTO), thereby solving the problems of low electronic conductivity, poor rate capability and insufficient energy density of the lithium titanate (LTO) negative electrode material.

The application relates to an aluminum-doped lithium titanate-coated ternary positive electrode material and a preparation method and application thereof. The preparation method comprises the following steps: adding metal salt solution, precipitant solution and complexing agent solution into a bottom liquid in parallel flow, and performing a coprecipitation reaction under stirring conditions; after the coprecipitation reaction is completed, the temperature and stirring speed are kept unchanged, aluminum-titanium solution, precipitant solution and ammonia solution are continuously mixed in parallel flow, and a spherical hydroxide is obtained after the reaction is completed; solutes in the aluminum-titanium solution include aluminum salt, titanium salt and hydrogen peroxide; a lithium source is mixed with the spherical hydroxide, and preheating treatment and heat treatment are sequentially performed to obtain the aluminum-doped lithium titanate-coated ternary positive electrode material. The preparation method adds the aluminum-titanium solution in the coprecipitation reaction process, forms an aluminum-doped lithium titanate precursor, and thus the aluminum-doped lithium titanate-coated ternary positive electrode material is obtained through heat treatment, and the interface stability is improved.

The invention discloses a chromium-site high-entropy chromium lithium titanate material as well as a preparation method and application thereof, and belongs to the technical field of electrochemical energy storage materials. The crystal structure of the chromium-site high-entropy chromium lithium titanate material is a single spinel solid solution phase, and the chemical general formula of the chromium-site high-entropy chromium lithium titanate material is Li (Cr < 1-x-y-z-w > V < x > Fe < y > Mn < z > Al < w >) TiO4. According to the preparation method, chromium trioxide serves as an oxidizing agent, carbohydrate serves as a reducing agent, and rapid synthesis is achieved through a one-step combustion method. The process is simple and efficient, and the prepared chromium-site high-entropy chromium lithium titanate material has relatively high specific capacity and excellent cycling stability and can be applied as a lithium ion battery negative electrode material. According to the invention, the problems of limited theoretical capacity and poor rate capability of the existing chromium lithium titanate material are effectively solved, and a new way is provided for developing a high-performance lithium ion battery negative electrode material.

The invention provides a membrane capacitive deionization module for treating brine with a high magnesium-lithium ratio as well as a preparation method and application of the membrane capacitive deionization module. The magnesium-lithium ratio of brine is 300-700, and the preparation method comprises the following steps: firstly, mixing and ball-milling an acid-washed lithium titanate molecular sieve, a binder, a conductive agent and a solvent, coating the surface of a whisker carbon nanotube membrane with the obtained slurry to form a coating, and then taking the whisker carbon nanotube membrane comprising the coating as an electrode, and assembling to obtain the membrane capacitive deionization module. Wherein the weight ratio of the acid-washed lithium titanate molecular sieve to the whisker carbon nanotube film is 1: (2-4). According to the membrane capacitive deionization module, efficient adsorption of lithium ions is achieved by utilizing high selectivity of the acid-washed lithium titanate molecular sieve, the whisker carbon nanotube membrane serves as a current collector, the module structure is simplified by utilizing high conductivity and large specific surface area of the whisker carbon nanotube membrane, rapid transmission of charges and uniform adsorption of the lithium ions are promoted, and the membrane capacitive deionization module is suitable for brine treatment; the method is especially suitable for brine with high magnesium-lithium ratio.

The invention discloses a cross-battery few-sample early prediction method and system based on physical knowledge, and the method comprises the steps: obtaining the test data of a target battery through an accelerated aging experiment, and training a general life prediction model based on an iTransform architecture through a public data set; an improved dynamic time warping algorithm is provided to realize capacity ratio alignment of degradation tracks of the target battery and the reference battery, and a characteristic difference value sequence representing systematic deviation is extracted; further constructing a deviation prediction model of multi-task learning, and synchronously optimizing three sub-tasks of feature reconstruction, physical feature prediction and health state deviation estimation through an adaptive loss weight adjustment mechanism; and finally, carrying out personalized correction on the general prediction result through a double-model fusion strategy. According to the invention, the cross-battery degradation track prediction of the lithium titanate battery of the high-speed train is completed, the prediction accuracy and generalization are improved, and a reliable technical means is provided for the health management of the battery.

The invention provides a CeO2 / RGO / LTO ternary composite material capable of being used as a negative electrode of a lithium ion battery and a preparation method and application of the CeO2 / RGO / LTO ternary composite material in the technical field of lithium battery electrode materials, and the CeO2 / RGO / LTO ternary composite material is formed by ternary compounding of cerium dioxide, reduced graphene oxide and lithium titanate. By means of step design, morphology control and interface construction, it is ensured that all components are evenly distributed, a strong synergistic effect is generated, the electrochemical performance of lithium titanate is remarkably improved, the problems that lithium titanate is low in conductivity and rapid in capacitance fading are solved, solidified lithium ions are converted into oxide with a stable structure, and the technical effect of restraining gas production is achieved. And the lithium ion battery is expected to be used for high-power and long-life lithium ion batteries, and particularly shows huge potential in the field with extremely high requirements on safety and fast charging performance.

The invention relates to the technical field of lithium ion batteries, and provides a negative plate and a lithium ion battery. The negative plate comprises a negative current collector and a negative active layer arranged on at least one side surface of the negative current collector, the negative active layer comprises a first active layer and a second active layer, and the second active layer is located between the negative current collector and the first active layer; the first active layer comprises a first active material, the first active material comprises lithium titanate, the second active layer comprises a second active material, and the second active material comprises a graphite material; after the negative plate is rolled, the porosity of the first active layer is recorded as A%, and the porosity of the second active layer is recorded as B%; a < B. The negative plate can effectively improve the rapid charging capability of the negative plate, reduce the lithium precipitation risk of the negative plate in the rapid charging process, improve the safety performance of the battery and prolong the cycle life of the battery.

The invention relates to the technical field of batteries, in particular to a negative plate, a preparation method thereof and a battery. The negative plate comprises a first negative electrode active layer, a second negative electrode active layer and a first functional layer which are sequentially arranged from the current collector to the outside; the first functional layer of the negative plate comprises at least three regions which are sequentially arranged along a first direction, the surface density of each region is sequentially reduced along the first direction of the negative plate, and the difference value of the surface densities of any two adjacent regions is 20-80%; and the first direction of the negative plate is a direction from the tab side to a direction far away from the tab side in the width direction of the negative plate. The electrolyte is deposited at the bottom of the battery, lithium titanate with low coating amount is arranged on one side close to the electrolyte, and lithium titanate with high coating amount is arranged on the upper side far away from the electrolyte at the bottom, so that the electrolyte can rapidly and fully infiltrate the pole piece, the pole piece can be fully infiltrated by the electrolyte, and the service life of the battery is prolonged. And the lithium ion intercalation and deintercalation efficiency in the charging and discharging process is improved, so that the conductivity is improved.