90 results about "Lithium aluminate" patented technology

The invention provides carbon-lithium aluminate double-layer coated lithium-rich lithium ferrite, which is characterized in that an aluminum source is used for reacting on the surface of lithium-rich lithium ferrite to coat a layer of lithium aluminate, and then a carbon source is used for coating to form the carbon-lithium aluminate double-coating layer coated lithium-rich lithium ferrite. The carbon-lithium aluminate double-layer coated lithium-rich lithium ferrite disclosed by the invention has relatively good lithium supplement performance, and can be used as a lithium supplement agent for a positive electrode of a lithium ion battery, so that the service life of the lithium ion battery is prolonged, and the long cycle performance of the lithium ion battery is improved. In addition, the invention also provides a preparation method and application of the carbon-lithium aluminate double-layer coated lithium-rich lithium ferrite.

The embodiment of the invention provides a preparation method of an NCA coated modified material, and belongs to the technical field of preparation of battery materials, the method comprises the following steps: providing nickel-cobalt-containing lithium aluminate NCA particles as a matrix material, and carrying out dispersion treatment on the NCA particles to ensure uniform particle size; the method comprises the following steps: forming a reaction mixing system by using a uniformly dispersed solution and a coating material containing aluminum oxide or magnesium oxide, and heating and stirring under a specific temperature condition so that the coating material can be effectively deposited on the surfaces of NCA particles; stirring is controlled based on preset time and speed parameters, and a coating material is promoted to be uniformly and firmly attached to the surfaces of NCA particles, so that the problem that a coating layer is not uniformly distributed or is poorly combined with a matrix is solved; and carrying out high-temperature heat treatment on the NCA particles with the coating layers under the protection of nitrogen so as to enhance the interface stability. Through the scheme of the embodiment of the invention, the problem of how to solve the problem of uneven distribution of the coating layer or poor combination with the matrix in the preparation process of the NCA coating modified material can be solved.

The invention relates to the technical field of lithium batteries, in particular to a preparation method of a high-temperature-resistant lithium battery cell. The invention discloses a preparation method of a high-temperature-resistant lithium battery cell, which is characterized in that through full-chain synergy of modification of positive and negative electrode materials, electrolyte optimization and structural design, a positive electrode adopts nickel cobalt lithium aluminate with a core-shell structure, and a metal organic framework coordination layer, polyaniline-polyacrylic acid multilayer coating and foam aluminum foil 3D printing coating are combined. The negative electrode takes silicon-carbon core-shell particles as a substrate, and breaks through the expansion bottleneck of a silicon-based negative electrode through metal organic framework confinement coating, polyaniline-polyacrylic acid cross-linked network modification and foam copper foil functionalization. The electrolyte adopts a film-forming additive and lithium difluorophosphate to form a stable SEI film, and internal resistance increase at high temperature is inhibited. The aramid fiber coating diaphragm and the aluminum alloy shell are matched, so that the thermal stability of the battery cell is remarkably improved, the battery cell can stably work in a wide temperature range environment, high energy density and long cycle life are comprehensively realized, and key support is provided for a long-endurance and high-safety battery.

The invention belongs to the technical field of waste lithium battery recovery, and particularly relates to a method for selectively extracting lithium from a waste lithium battery positive electrode material based on activation and oxidation, which comprises the following steps: mixing the waste lithium battery positive electrode material, an oxidizing agent, an activating agent and a solvent, stirring and leaching, and carrying out solid-liquid separation to obtain a lithium-rich leaching solution and valuable metal leaching residues; wherein the activating agent is one or more than two of divalent ferrite, divalent cobalt salt, divalent manganese salt, divalent copper salt and monovalent silver salt, and the waste lithium battery positive electrode material is selected from one or more than two of waste nickel cobalt lithium manganate batteries, waste nickel cobalt lithium aluminate batteries, waste lithium cobalt oxide batteries and waste lithium manganate batteries. Through the synergistic effect of the oxidizing agent and the activating agent, preferential extraction of lithium in the raw material is achieved in one step, the problem that the lithium loss amount is large in the later lithium extraction process is solved, and the method has the advantages of being easy and convenient to operate, short in technological process, good in lithium selectivity, high in lithium leaching rate, wide in temperature application range and low in recovery cost.

The invention belongs to the technical field of lithium ion batteries, and particularly relates to a lithium nickel cobalt aluminate / carbon composite positive electrode material with a core-shell structure and a spray drying process thereof, the lithium nickel cobalt aluminate / carbon composite positive electrode material comprises the following raw materials: a lithium source, an iron source, a phosphorus source, a carbon source and a solvent; the method specifically comprises the following steps: S1, dissolving a lithium source, an iron source, a phosphorus source and a carbon source in a solvent, mixing according to a stoichiometric ratio, adjusting the pH value by using ammonia water or citric acid, and adding a binder to adjust the viscosity to obtain a precursor solution; s2, atomizing the precursor solution into tiny liquid drops by a centrifugal or pressure type spray dryer through a nozzle or a centrifugal disc, and staying the liquid drops in a tower for 4-10 seconds to obtain a dried microsphere precursor; s3, presintering the dried microsphere precursor in an inert atmosphere at 300-400 DEG C through a firing device, and removing volatile components; and S4, cooling the pre-sintered and dried microsphere precursor, and calcining in the firing device again to form crystals.

A negative electrode active material for a non-aqueous electrolyte secondary battery according to one example of an embodiment comprises composite particles (30) that include a lithium aluminate phase (31) and a silicon phase (32) dispersed in the lithium aluminate phase (31). The lithium aluminate phase (31) contains boron, and the ratio (MAI / MB) of the aluminum percentage content (MAI) and the boron percentage content (NIB) with respect to the total amount of the elements other than oxygen constituting the lithium aluminate phase (31) and the silicon phase (32) is 1.0-30.0, inclusive.

The invention discloses a long-life lithium manganese iron phosphate positive electrode material and a preparation method thereof, and relates to the technical field of lithium ion battery positive electrode materials. The long-life lithium manganese iron phosphate positive electrode material comprises lithium manganese iron phosphate, a middle coating layer and a carbon coating layer, the surface of the lithium manganese iron phosphate is coated with the middle coating layer, the surface of the middle coating layer is coated with the carbon coating layer, the middle coating layer contains metal fluoride and aluminum-containing sinter, and the aluminum-containing sinter comprises aluminum oxide and lithium metaaluminate. The synergistic coating of the middle coating layer and the carbon coating layer can effectively reduce the contact between the positive electrode material and an electrolyte, inhibit the generation of surface side reactions, improve the stability of the electrode material structure, and have low manganese dissolution and excellent cycle life.

The invention provides a composite oxide solid electrolyte sheet and a preparation method and application thereof. The preparation method comprises the following steps: pressing oxide solid electrolyte powder into a sheet, and performing first calcination to obtain an oxide solid electrolyte sheet; placing the oxide solid electrolyte sheet in the reaction solution, and heating for reaction; the reaction solution comprises a lithium-containing compound and an aluminum-containing compound; and carrying out second calcination on the reacted oxide solid electrolyte sheet to obtain the composite oxide solid electrolyte sheet with the surface coated with the lithium metaaluminate layer. The technical problems to be solved are how to enable the composite oxide solid electrolyte sheet to be low in grain boundary impedance and high in ionic conductivity, improve the stability of the oxide solid electrolyte to lithium, improve the compatibility of the oxide solid electrolyte and a pole piece and reduce the contact impedance. When the composite oxide solid electrolyte sheet is applied to an all-solid-state battery or a semi-solid-state battery, the all-solid-state battery or the semi-solid-state battery has relatively good rate capability and cycle performance.

The invention provides a lithium aluminate modified graphite negative electrode material, a preparation method thereof and a graphite negative electrode plate, and belongs to the technical field of graphite negative electrodes. The preparation method comprises the following steps: mixing a dopamine hydrochloride solution with graphite particles, adjusting the pH value to 7.5-8.5, and drying to obtain polydopamine-coated graphite; and mixing the polydopamine-coated graphite, an aluminum salt solution and a lithium-containing compound solution, sequentially carrying out drying and solid-phase reaction to obtain a lithium aluminate modified graphite negative electrode material, and preparing the lithium aluminate modified graphite negative electrode material into a graphite negative electrode plate. The lithium aluminate modified graphite negative electrode material is composed of the graphite particle core and the lithium aluminate shell layer, lithium aluminate has very strong mechanical performance and high thermal stability, not only can protect the graphite material from being corroded by electrolyte, but also can reduce the diffusion energy barrier of lithium ions, limit the volume expansion of the graphite particles and stabilize the SEI film on the graphite surface, so that the lithium aluminate modified graphite negative electrode material can be used for the lithium ion battery. Therefore, the transmission of lithium ions is promoted.

The invention relates to the technical field of solid-state batteries, in particular to a eutectic solid-state electrolyte diaphragm, a preparation method thereof and a solid-state battery. The preparation method of the eutectic solid electrolyte diaphragm comprises the following steps: mixing oxygen-containing lithium tetrachloroaluminate and imide lithium salt, melting and quenching, and pressing; wherein the chemical formula of the oxygen-containing lithium aluminum tetrachloride is LiAlCl < 4-2x > O < x >, and x < lt > is greater than or equal to 0.01; 2; the imide lithium salt comprises lithium bis (fluorosulfonyl) imide and / or lithium bis (trifluoromethylsulfonyl) imide. The preparation method is simple and low in cost, is similar to a traditional liquid battery process, and can quickly realize batch production; and the eutectic solid electrolyte diaphragm prepared by the method has high ionic conductivity, wide electrochemical window, good thermal stability and good interface compatibility.

The invention relates to a lithium metaaluminate coated lithium iron manganese phosphate positive electrode material and a preparation method thereof, and the positive electrode material is mainly prepared by the following method: (1) adding a lithium iron manganese phosphate positive electrode material into an organic aqueous solution containing an aluminum source and a lithium source, stirring and mixing to obtain a lithium iron manganese phosphate positive electrode material metal ion dispersion liquid; (2) stirring and evaporating the metal ion dispersion liquid of the lithium iron manganese phosphate positive electrode material obtained in the step (1) until the metal ion dispersion liquid is evaporated to dryness, performing vacuum drying, and grinding to obtain mixed powder of the lithium iron manganese phosphate positive electrode material; and (3) calcining the lithium manganese iron phosphate positive electrode material mixed powder obtained in the step (2) in an inert atmosphere to obtain the lithium metaaluminate coated lithium manganese iron phosphate positive electrode material. The lithium iron manganese phosphate positive electrode material coated with the lithium metaaluminate is good in coating effect, good in conductivity, good in electrochemical performance under high magnification, ultra-long in cycle stability, simple and controllable in process, short in flow and suitable for industrial production.

The invention discloses an in-situ polymerization gel polymer electrolyte, a preparation method thereof and a silicon-based lithium ion battery, and belongs to the technical field of solid electrolyte. Fluorine-atom-containing fluoromethacrylate is introduced into polyethylene glycol diacrylate for copolymerization modification, in-situ polymerization is carried out in the battery to form a three-dimensional network structure, and a copolymer of polyethylene glycol diacrylate (PEGDA) and fluoromethacrylate is used as a skeleton, so that liquid electrolyte can be firmly locked in a polymer matrix; a chemical integrated interface is generated in the battery curing stage, and the interface performance is improved. Compared with a liquid electrolyte, the electrolyte battery has the advantages that the cycle life is greatly prolonged and the safety is improved on the premise that the capacity is well exerted. Moreover, the positive electrode material is well compatible with various positive electrode materials such as nickel cobalt lithium manganate and nickel cobalt lithium aluminate, and a comprehensive solution for buffering volume change, stabilizing an interface and improving safety is provided for the silicon-based lithium ion battery.

The present invention relates to a method for recovering lithium from a stream containing lithium, the method comprising contacting the stream, or a pre-treated solution obtained from said stream, with sodium aluminate to form a slurry comprising a lithium aluminate precipitate, at an alkaline pH; and recovering the slurry containing said lithium aluminate, or a precipitate therefrom.

The invention provides a method for recovering lithium in a sodium aluminate solution, and belongs to the technical field of lithium recovery. According to the method, a saturated solution containing carbonate and / or a saturated solution containing bicarbonate and a stabilizer are added into a lithium-containing sodium aluminate solution, carbonate or bicarbonate ions and lithium ions and aluminate ions in the sodium aluminate solution are subjected to a co-precipitation reaction, Li2Al4CO3 (OH) 12. 3H2O solid precipitate is generated, and meanwhile, due to the addition of the stabilizer, the lithium aluminate solution is subjected to a co-precipitation reaction, so that the lithium aluminate solution is obtained. According to the method, the stability of a sodium aluminate solution is improved, precipitation of aluminum hydroxide can be controlled, all lithium-rich solid phases are lithium-aluminum hydrotalcite Li2Al4CO3 (OH) 12. 3H2O, and the lithium-rich solid phases can be obtained after the lithium-rich solid phases are directly subjected to solid-liquid separation. The method has the advantages of simple process, short flow and few types of used raw materials, and the lithium-rich solid phase obtained by the method has the advantages of low impurity content and high lithium recovery rate, and is beneficial to subsequent lithium application.

This invention discloses a preform for the hot top of a crystallizer specifically for semi-continuous casting of aluminum-lithium alloys and its manufacturing method. Addressing the problems of severe interfacial reactions between existing refractory materials and molten aluminum-lithium alloys, resulting in poor forming quality of semi-continuous casting ingots, this invention employs a gradient composite structure design: lithium aluminate is introduced into the working layer to thermodynamically suppress interfacial reactions by increasing the intrinsic lithium chemical sites; the insulation layer contains β-lithium nepheline and lithium aluminate to improve the insulation performance and thermal shock resistance of the hot top. Furthermore, by using a gradient distribution of lithium compound concentrations and types, combined with a multi-stage sintering process, the interlayer bonding strength is improved. Results show that this invention not only significantly reduces the interfacial reaction between the molten aluminum-lithium alloy and the hot top during semi-continuous casting, improving the forming quality of aluminum-lithium alloy ingots, but also extends the service life of the preform.

The invention belongs to the technical field of quantum dot glass ceramics, and relates to high-modulus multiphase quantum dot glass ceramics as well as a preparation method and application thereof. The microcrystalline glass comprises eucryptite (LiAlSiO4), lithium aluminate (LiAlO2) and quantum dots (CsPbBr3), wherein the eucryptite (LiAlSiO4) and the lithium aluminate (LiAlO2) are main crystalline phases. The surface of the LiAlO2 crystal phase is coated with the LiAlSiO4 crystal phase or gaps of the LiAlO2 crystal phase are filled with the LiAlSiO4 crystal phase to form a multi-phase reinforced structure, and the CsPbBr3 quantum dot glass ceramic has excellent water stability and deformation resistance. The preparation method comprises the following steps: respectively preparing a basic glass batch and a CsPbBr3 quantum dot precursor, and carrying out melting, water quenching and grinding on the glass batch to obtain basic glass powder; the preparation method comprises the following steps: placing a quantum dot precursor at the bottom of a platinum crucible by adopting a layered loading process, then covering basic glass powder, and finally obtaining the quantum dot microcrystalline glass through melting homogenization, casting molding and controlled heat treatment. The method is simple in process and high in controllability; the obtained product is excellent in comprehensive performance and good in application prospect.

The invention discloses an electrochemical device and an electronic device, the electrochemical device comprises a positive pole piece, a negative pole piece and a non-aqueous electrolyte, the positive pole piece comprises a positive pole material layer, the negative pole piece comprises a negative pole material layer, and the negative pole material layer comprises a negative pole material; the positive electrode material layer comprises a nickel cobalt lithium manganate material and / or a nickel cobalt lithium aluminate material, the mass content of a nickel element in the positive electrode material layer is m%, and m is larger than or equal to 29 and smaller than or equal to 56.5; the negative electrode material comprises a silicon element, the mass content of the silicon element in the negative electrode material layer is e%, and e is larger than or equal to 3.5 and smaller than or equal to 60; the non-aqueous electrolyte comprises fluoroethylene carbonate and a compound shown in a formula I, based on the total mass of the non-aqueous electrolyte, the mass content of the compound shown in the formula I is a%, the mass content of fluoroethylene carbonate is b%, a is larger than or equal to 0.5 and smaller than or equal to 20, b is larger than or equal to 1 and smaller than or equal to 30, and a / b is larger than 0.2 and smaller than or equal to 4.

The invention discloses a process method for coating a modified positive electrode material with a solid electrolyte. The process method specifically comprises the following steps: S1, pretreating the positive electrode material; s2, preparing lithium metaaluminate sol; s3, carrying out coating treatment; s4, washing and drying; s5, calcining treatment; s6, carrying out post-treatment; the invention relates to the technical field of battery materials. According to the process method for coating the modified positive electrode material with the solid electrolyte, through composite coating of the solid electrolyte and the carbon material, the electronic conductivity, the cycling stability and the rate capability of the positive electrode material are remarkably improved, and a solid electrolyte coating layer can effectively protect the positive electrode material and prevent the positive electrode material from being in direct contact with electrolyte; therefore, the safety and stability of the lithium ion battery are improved, the preparation method is simple and convenient to operate, easy to control and suitable for large-scale industrial production, the adopted materials are low in cost, no complex equipment is needed in the preparation process, the production cost is reduced, and both the organic solvent and the stabilizer used in the preparation process can be recycled.

The present application provides a method for preparing a positive electrode active material, a positive electrode active material, a positive electrode plate, a secondary battery and an electric device. The method for preparing a positive electrode active material comprises the following steps: discharging a waste nickel cobalt manganese oxide lithium secondary battery, drying and disassembling to obtain a positive electrode plate, and roasting to remove impurities; dissolving the obtained positive electrode plate with acid, filtering to obtain a mixed solution, adding a metal salt to adjust the molar ratio of the metal elements, causing a coprecipitation reaction in an alkaline solution, and filtering to obtain a nickel cobalt manganese aluminum oxide lithium precursor; recrystallizing the filtrate to obtain lithium hydroxide; and roasting the nickel cobalt manganese aluminum oxide lithium positive electrode active material after mixing the nickel cobalt manganese aluminum oxide lithium precursor with lithium hydroxide. The method for preparing a positive electrode active material provided by the present application eliminates the step of separating the active substance and the aluminum foil, simplifies the recycling method, and improves the recycling efficiency.

The present disclosure relates to a halogen-doped nickel-cobalt-lithium aluminate, a preparation method and application thereof, the method comprising the following steps: S1, mixing nickel hydroxide with an aluminum source in a first solid phase to obtain a first solid material; S2, mixing the first solid material with a cobalt source in a second solid phase, and performing a first heat treatment on the obtained mixture in a first oxygen-containing atmosphere to obtain a second solid material; S3, mixing the second solid material with a lithium source in a third solid phase, and performing a second heat treatment on the obtained mixture in a second oxygen-containing atmosphere; the cobalt source and / or the aluminum source contain halogen. The method has simple steps, is conducive to industrial scale-up implementation and batch production, and the prepared halogen-doped nickel-cobalt-lithium aluminate has relatively uniform mixing of elements; when used as a positive electrode material of a lithium ion battery, the halogen-doped nickel-cobalt-lithium aluminate has a high specific capacity and good cycle performance.

The application discloses a lithium aluminate composite saggar and a preparation method and application thereof, and belongs to the technical field of saggar, wherein the saggar comprises an inner surface working layer and an outer matrix layer from inside to outside; the thickness of the inner surface working layer is 1-3 mm; the inner surface working layer comprises the following preparation raw materials in parts by weight: synthetic lithium aluminate 5-20 parts, kaolin 2-10 parts, fused zirconium mullite 0-10 parts, zirconium oxide 0-15 parts, zirconium silicate 0-10 parts, spinel 60-80 parts, alumina 0-10 parts, organic binder 0-5 parts, and water 1-5 parts. The synthetic lithium aluminate is added in the saggar formula system, the structure is solidified during saggar firing, according to the principle of Fick's first law, the addition of lithium aluminate can slow down the alkali corrosion of the material to the saggar, effectively restrict the volume change in the positive electrode material, and effectively improve the service life of the saggar.

The invention relates to the technical field of lithium ion batteries, and discloses a lithium ion battery cell and a method for detecting the dissolved amount of transition metal. The lithium ion battery cell comprises a roll core formed by winding a positive plate, a diaphragm and a negative plate, electrolyte and a metal shell used for placing the roll core, the positive plate comprises a positive current collector and a positive active material substance layer coated on at least one surface of the positive current collector, and the negative plate comprises a negative current collector and a positive active material substance layer coated on at least one surface of the positive current collector. The positive electrode active material substance layer comprises one or more of lithium iron phosphate, lithium iron manganese phosphate, nickel cobalt lithium manganate, nickel cobalt lithium aluminate, nickel cobalt manganese lithium aluminate, spinel lithium manganate, spinel nickel lithium manganate and layered lithium manganate, and the dissolved amount of transition metal Mn in the battery cell is less than or equal to 0.02 g / Ah.

The present invention provides a method for preparing a pH indicator electrode based on the modification of lithium-ion battery ternary materials, and selects commercial and inexpensive lithium-ion battery ternary electrode materials (lithium nickel cobalt manganese oxide / NCM or lithium nickel cobalt aluminum oxide / NCA), or even discarded NCM or NCA, as active substances, and obtains an all-solid-state pH indicator electrode with excellent performance after a series of modification and stabilization treatments, in order to solve the problem of long-term, in-situ monitoring of ocean pH. Through the technical solution of the present invention, the all-solid-state pH indicator electrode of the present invention and its preparation method have the advantages of simple manufacturing, low cost, good pH response characteristics, high response accuracy, strong pressure resistance, corrosion resistance and anti-fouling performance, and small potential drift, and are particularly suitable for long-term, in-situ and real-time monitoring of seawater pH in the deep sea.

The invention provides a method for efficiently improving the performance of a nickel ternary material, which comprises the following steps: adding a solution containing aluminum ions into a positive electrode material, grinding, uniformly mixing, heating and calcining in an air atmosphere to obtain a modified high-nickel ternary material, preparing lithium titanate, putting the lithium titanate and the modified high-nickel ternary material into an organic solvent, uniformly mixing, heating, stirring, evaporating to dryness, grinding and sieving to obtain a precursor; and heating the precursor for 1-2 hours at the temperature of 700-800 DEG C in an inert atmosphere, and naturally cooling. According to the method, the high-nickel ternary material is subjected to surface treatment through a solution containing aluminum ions, Li2CO3 and LiOH existing on the surface of the high-nickel material are absorbed to reduce the content of lithium salt impurities in the positive electrode material, alkaline residues on the surface of the electrode material are reduced, and the interface transfer impedance of the electrode material is reduced; and meanwhile, a small amount of lithium metaaluminate is synthesized to coat the surface of the ternary material, so that the cycling stability and thermodynamic property of the high-nickel material are improved.

The invention relates to the technical field of positive electrode material modification, in particular to a positive electrode material and a modification method thereof. The modification method of the positive electrode material provided by the invention comprises the following steps: S1, mixing a precursor, a lithium source and a doping material, and carrying out primary sintering to obtain a primary sintered material, the doping material comprising an aluminum source, an antimony source and a zirconium source; s2, washing the first sintered material with water, and carrying out solid-liquid separation to obtain an intermediate; and S3, mixing the intermediate with boric acid and lithium metaaluminate, and carrying out secondary sintering to obtain the modified positive electrode material. The three elements of aluminum, zirconium and antimony are doped, so that the direct-current resistance is effectively reduced, the side reaction in the material is reduced, and the de-intercalation rate of lithium ions is improved. According to the invention, before coating, residual alkali on the surface of the material is washed off by setting the step of washing and coating, so that the cycle performance of the positive electrode material is further improved, and meanwhile, boric acid and lithium metaaluminate are used for isolating the contact between the positive electrode material and an electrolyte to a great extent, so that the cycle performance of the material is improved.

The invention relates to a nickel-cobalt-aluminum precursor with a two-phase structure as well as a preparation method and application of the nickel-cobalt-aluminum precursor. The nickel-cobalt-aluminum precursor comprises secondary particles containing nickel-cobalt hydroxide and Al (OH) 3. The nickel-cobalt-aluminum precursor prepared by adopting the method disclosed by the invention is relatively large in particle size and high in tap density, the tap density and the electrochemical performance can be improved by using the nickel-cobalt-aluminum precursor to prepare the nickel-cobalt-lithium aluminate ternary material, and the batch stability of the material can be improved.

The invention relates to the technical field of batteries, in particular to a negative plate and a lithium ion secondary battery comprising the same. The negative plate comprises a negative active coating, the negative active coating comprises a silicon-based material, and the silicon-based material comprises silicon-carbon particles and a coating layer located on the outer surfaces of the silicon-carbon particles; the coating layer comprises a first coating layer and a second coating layer; the second coating layer at least comprises lithium metaaluminate; based on the total weight of the silicon-based material, the mass content of Al in the second coating layer is A, and the unit is ppm; a plurality of first concave parts are arranged on the surface of the negative electrode active coating on at least one side surface of the negative electrode current collector, the depth of each first concave part is H, and the unit is mu m; and the mass content A of Al in the silicon-based material and the depth H of the first concave part meet the condition that H / A is more than or equal to 0.002 and less than or equal to 0.669. According to the lithium ion secondary battery, the structural stability of the negative plate is remarkably improved, and the lithium ion secondary battery has excellent rate capability and cycle performance.

The invention relates to the technical field of solid-state batteries, in particular to a eutectic solid-state electrolyte coating diaphragm, a solid-state battery and a preparation method of the solid-state battery. The preparation method of the eutectic solid electrolyte coated diaphragm comprises the following steps: coating a base membrane with slurry, and then drying; the slurry is mainly composed of oxygen-containing lithium tetrachloroaluminate and lithium bis (fluorosulfonyl) imide, the chemical formula of the oxygen-containing lithium tetrachloroaluminate is LiAlCl4-2xOx, and x < lt > is larger than or equal to 0.01; 2. The eutectic solid electrolyte coated diaphragm prepared by the invention contains the eutectic solid electrolyte, and the interface wettability between the eutectic solid electrolyte and the base membrane is good, so that the lithium ion transmission efficiency can be improved; and the eutectic solid electrolyte can uniformly permeate into the base membrane and the positive and negative electrode materials through a hot pressing process, so that the contact uniformity is improved, and the interface impedance between the electrode and the eutectic solid electrolyte is reduced, thereby improving the battery performance.

The invention relates to the technical field of lithium ion battery positive electrode materials, and discloses a modified high-nickel NCA positive electrode material and a preparation method and application thereof. The modified high-nickel NCA positive electrode material comprises an inner core, a first coating layer and a second coating layer which are sequentially arranged from inside to outside, the inner core comprises nickel cobalt lithium aluminate doped with a hafnium element; the first coating layer comprises copper oxide; and the second coating layer comprises a lithium fast ion conductor. In the modified high-nickel NCA positive electrode material provided by the invention, hafnium doping stabilizes a crystal structure from a bulk phase angle, double-layer coating synergistic effect inhibits side reaction from an interface angle, and the two layers cooperate to solve the problem of bulk phase-interface synergistic attenuation of the material, so that the positive electrode material has high capacity, long cycle life and excellent rate capability.

The invention relates to the technical field of positive electrode materials, in particular to a high-rate lithium nickel cobalt aluminate positive electrode material and a preparation method thereof. The invention provides a preparation method of a high-rate nickel cobalt lithium aluminate positive electrode material, which comprises the following steps: S1, mixing a nickel cobalt precursor, a lithium source, an aluminum source and a zirconium source, and sintering to obtain a first sintered material; and S2, mixing the lithium titanium phosphate and the sintering material, then mixing the mixture with the single-walled carbon nanotubes, and sintering the mixture to obtain the high-rate lithium nickel cobalt aluminate positive electrode material. The lithium titanium phosphate and the single-arm carbon nanotube are used for coating modification, so that the contact between the positive electrode material and an electrolyte can be isolated to a great extent, and the cycle performance of the material is improved; the surface of the material is coated with the single-arm carbon nanotubes and aluminum, so that the migration rate of lithium ions can be increased, and lithium titanium phosphate has high ionic conductivity, so that the lithium ions are allowed to quickly diffuse in a three-dimensional channel to form a continuous ion transmission network.