128results about "Alkali titanates" patented technology

The invention discloses sodium titanate with a layered crystal structure, a preparation method of the sodium titanate and application of the sodium titanate in a water-based magnesium ion battery, and belongs to the technical field of water-based magnesium ion batteries. According to the invention, the sodium titanate with a layered crystal structure is used as the negative electrode material of the aqueous magnesium ion battery, and due to excellent chemical and structural stability, the sodium titanate can realize reversible Mg < 2 + > intercalation / deintercalation in an aqueous magnesium electrolyte. According to the invention, Na2Ti2O5 and Na2Ti3O7 materials are synthesized by a hydrothermal method and a high-temperature annealing process. In a magnesium chloride electrolyte, the two sodium titanate materials both show extremely low charge and discharge potentials (Na2Ti2O5,-1.3 to-0.6 V vs.SCE; sCE (-1.5 to-1 V vs.SCE) and relatively good cycling stability are achieved. In addition, the charge-discharge specific capacity of the Na2Ti2O5 half cell under the current density of 2A / g is up to 213mAh / g, and the high specific capacity of 150mAh / g is still kept under the high current density of 10A / g. The sodium titanate is an ideal aqueous magnesium battery negative electrode material, has the advantages of low cost and environmental friendliness, and has a great application prospect in the field of aqueous magnesium ion energy storage.

This invention provides a titanium-layer-constructed, synergistic low-eutectic salt regenerated waste lithium nickel cobalt manganese oxide cathode material. The preparation method includes the following steps: cutting the electrode sheet and placing it in an N-methylpyrrolidone solution, ultrasonically dissolving, filtering, washing, drying, and sieving to obtain the waste lithium nickel cobalt manganese oxide material; mixing the obtained waste lithium nickel cobalt manganese oxide cathode material with a titanium source, then adding a lithium source and mixing evenly to obtain a composite material; sintering the composite material in a two-stage process under an oxidizing atmosphere, cooling to room temperature, to obtain the regenerated waste lithium nickel cobalt manganese oxide cathode material with lithium replenishment and repair. The resulting material has a core-shell coated structure, with a lithium metatitanate layer as the coating layer and a titanium-doped lithium nickel cobalt manganese oxide core. The regenerated material exhibits uniform doping and coating, excellent rate performance, and significantly improved charge / discharge capacity and cycle stability.

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.

In a titanium oxide powder of this invention, a ratio (IA / IR) of a peak intensity (IA) of anatase-type crystals to a peak intensity (IR) of rutile-type crystals as measured by X-ray diffractometry is 0.1 or less; particles contained in the powder have an average short-axis length from 10 to 50 nm and an average aspect ratio from 1 to 3; a ratio (A450 / A320) of an absorbance A450 at a wavelength of 450 nm to an absorbance A320 at a wavelength of 320 nm is from 0.015 to 0.5; and the powder contains a nitrogen atom and a peak derived from the nitrogen atom is observed from 395 to 402 eV in ESCA (Electron Spectroscopy for Chemical Analysis) measurement. A titanium oxide powder is thus provided that contains rutile-type crystals as a main component and has an excellent UVA shielding effect, high safety for the human body, and good color tone.

A titanium-containing oxide powder which is mainly composed of a titanium-containing oxide represented by Li4Ti5O12 or Ti1-X / 2Nb2O7-X (wherein 0 ≤ X < 2), and which is characterized by containing particles of the titanium-containing oxide and a solvation ionic liquid that is composed of an Li salt and an organic solvent.

This invention discloses a type of sodium titanate with a layered crystal structure, its preparation method, and its application in aqueous magnesium-ion batteries, belonging to the field of aqueous magnesium-ion battery technology. This invention uses sodium titanate with a layered crystal structure as the negative electrode material in aqueous magnesium-ion batteries. Due to its excellent chemical and structural stability, sodium titanate can achieve reversible magnesium deposition in aqueous magnesium electrolytes. 2+ Intercalation / extraction. This invention synthesizes Na via a hydrothermal method and a high-temperature annealing process. 2 Ti 2 O 5 And Na 2 Ti 3 O 7 Materials. In magnesium chloride electrolyte, both sodium titanate materials exhibit extremely low charge / discharge potentials (Na). 2 Ti 2 O 5 -1.3 to -0.6V vs. SCE; Na 2 Ti 3 O 7 (-1.5 to -1V vs. SCE) and good cycle stability. Furthermore, Na... 2 Ti 2 O 5 The half-cell exhibits a charge-discharge specific capacity of up to 213 mAh / g at a current density of 2 A / g, and maintains a high specific capacity of 150 mAh / g even at a high current density of 10 A / g. The sodium titanate of this invention is an ideal anode material for aqueous magnesium batteries, possessing both low cost and environmental friendliness, and shows great promise for application in the field of aqueous magnesium-ion energy storage.

A method for preparing a nano-titanate, a nano-titanic acid and a nano-TiO2 containing embedded A nanoparticles is provided respectively. In this method, a Ti-T alloy with a A-group element solidly dissolved therein is used as a titanium source, and reacted with an alkali solution under a certain condition. In combination with subsequent treatment, the preparation of a titanate nanotube, a titanic acid nanotube, and a TiO2 nanotube / rod containing embedded A nanoparticles, respectively, is further achieved with high efficiency and low cost. Moreover, a method for preparing metal nanoparticles is also provided by removing the matrix of the composites. The present preparation methods is characterized by simple process, easy operation, high efficiency, low cost. The product is of promising application in polymer-based nanocomposites, ceramic materials, catalytic materials, photocatalytic materials, hydrophobic materials, effluent degrading materials, bactericidal coatings, anticorrosive coatings, marine coatings.

The invention discloses a production system of high-flowability moisture-proof sodium potassium titanate, and relates to the technical field of sodium potassium titanate, the production system comprises a pulsed electric field in-situ moisture-proof layer synthesis unit, a multistage cyclone coupling fluidized bed modification unit and a block chain quality closed-loop control unit, the pulsed electric field in-situ moisture-proof layer synthesis unit comprises a nitrogen-protected closed reaction kettle, a high-frequency ultrasonic disperser and a multi-stage pulsed electric field generator, the high-frequency ultrasonic disperser applies a 0.5-20 MHz pulsed electric field, the field intensity of the pulsed electric field is 10-30 kV / cm, the duty ratio of the pulsed electric field is 15%-90%, and the multi-stage pulsed electric field generator is used for generating the moisture-proof layer. The high-frequency ultrasonic disperser enables a nano rare earth silicate composite coating layer to be generated in situ on the surface of sodium potassium titanate particles, the thickness of the nano rare earth silicate composite coating layer is 10-50 microns, the humidity sensitivity of the nano rare earth silicate composite coating layer is 0.1%-0.3%, the multi-stage rotational flow coupling fluidized bed modification unit comprises three stages of fluidized beds which are arranged in series, and the three stages of fluidized beds are connected in parallel. The inclination angle of the inclination-angle-adjustable swirl nozzle array arranged at each stage is 10-60 degrees, and the distance is 1.2-2.5 times of the particle diameter.

The present invention relates to a negative electrode active material for a lithium secondary battery, a method for preparing same, and a lithium secondary battery comprising same. More specifically, the negative electrode active material comprises one selected from Li1.1Ti0.9O2 and a mixture in which Li1.1Ti0.9O2 and carbon nanotubes (CNTs) are mixed in a weight ratio of 8:2 to 9:1. The negative electrode active material for a lithium secondary battery, comprising the above-described components has an R-3m structure, and provided is a lithium secondary battery which exhibits high capacity and excellent lifespan characteristics, and in particular, exhibits high capacity during high-rate charging and discharging.

The invention discloses a preparation method of fibrous potassium hexatitanate, which comprises the following steps: uniformly mixing organic amine and a titanium-containing compound, and adding alcohol; heating the mixture, adding a potassium-containing compound in the heating process, and uniformly mixing again; adding a spinning aid into the obtained mixture, and then carrying out microfluidic spinning; finally, a sample obtained after spinning is calcined, and fibrous potassium hexatitanate is finally prepared. The preparation method is simple to operate, short in production period, free of waste acid emission, low in cost, environment-friendly and efficient. The average diameter of the prepared fibrous potassium hexatitanate is larger than or equal to 15 micrometers, the fibrous potassium hexatitanate is in a thick rod shape and uniform in morphology, the mechanical property and stability of the composite material can be remarkably improved, and the fibrous potassium hexatitanate is not prone to being sucked into the human body and entering blood or lymph.

The present invention discloses a preparation method of carbon-modified titanate with a high aspect ratio, which comprises the following steps: attapulgite, starch, orthotitanic acid, a potassium-containing precursor and furfuryl alcohol are mixed, and stirred to enable the starch, orthotitanic acid and potassium-containing precursor to fully immerse into the pores of rod-shaped attapulgite, and drying is carried out at a controlled temperature of 80-100 °C to obtain titanium source / potassium source / carbon source / attapulgite; the titanium source / potassium source / carbon source / attapulgite is put into a crucible, a tube furnace is used as a heating device, and reaction is carried out at 750-900 °C for 90 min, and an inert atmosphere is passed throughout the reaction; after cooling with the furnace, it is centrifugally washed with deionized water, and then dried at 80 °C for 6-8 h to obtain carbon-modified titanate with a high aspect ratio. The carbon-modified potassium hexatitanate with a high aspect ratio based on attapulgite has good fluidity and will not generate fibers during friction, playing a role in increasing strength and wear resistance, so that the friction coefficient of the whole friction material is relatively more stable and the high-temperature recession rate is lower.

Provided are: coated flaky titanic acid particles, which can form a design coating film with a good silky texture and shadowed appearance when flaky titanic acid is applied to an organic solvent-based paint and, which can also sufficiently suppress discoloration (yellowing) of the coating film even in a relatively severe environment, such as prolonged exposure to ultraviolet light; and a production method therefor.　The surface of the flaky titanic acid particles has an oxide and / or hydroxide of aluminum, and an anionic surfactant present thereon. Preferably, the anionic surfactant is a hydrocarbon-based anionic surfactant having 5 or more carbon atoms in the main chain or a fluorinated anionic surfactant having 4 or more carbon atoms. Said production method comprises: a step for maintaining an aqueous slurry, which contains flaky titanic acid particles and an aluminum source, at a temperature of 50-95°C inclusive and at a pH of 5-12 inclusive to treat the surface of the flaky titanic acid particles with an oxide and / or hydroxide of aluminum; and a subsequent step for mixing the obtained flaky titanic acid and an anionic surfactant in a solution.

The invention discloses a positive and negative electrode interface cooperative processing method of an LTO-LMFP all-solid-state battery. The method comprises the following steps: preparing a lithium titanate negative electrode material by adopting a solid phase method or a hydrothermal method; mixing the prepared lithium titanate powder with a lithium phosphate precursor according to a certain proportion; after mixing, carrying out heat treatment on the mixture to promote the lithium phosphate to uniformly form a coating layer on the surfaces of the lithium titanate particles; a coprecipitation method or a solid-phase method is adopted to prepare the lithium manganese iron phosphate positive electrode material, so that the interface impedance is obviously reduced, and the physical contact and chemical compatibility between the electrode material and a sulfide solid electrolyte are effectively improved through a lithium phosphate coated lithium titanate negative electrode and a Mg-doped manganese phosphate coated lithium manganese iron phosphate positive electrode. The lithium phosphate and manganese phosphate coating layer is used as an interface buffer layer and can fill interface gaps, increase the effective contact area and provide a more stable ion transmission channel, so that the interface impedance between the positive electrode and the negative electrode and the solid electrolyte is greatly reduced, and rapid migration of lithium ions is promoted.

The present invention relates to a method for preparing a nano-titanate, a nano-titanic acid and a nano-TiO2 containing doping E or embedding E nanoparticles, and the use thereof. By using an E-doped Ti-T intermetallic compound as a titanium source, and reacting the E-doped Ti-T intermetallic compound with alkaline solution at atmospheric pressure and near its boiling-point temperature, an E-doped titanate nanofilm is prepared at atmospheric pressure with high efficiency and in a short time. Through acid treatment and (or) heat treatment, a titanate nanofilm containing embedding E nanoparticles, an E-doped titanic acid nanofilm, and a titanic acid nanofilm and a TiO2 flake powder containing embedding E nanoparticles can be further prepared. Through a subsequent reaction at high temperature and pressure, the preparation of an E-doped titanate nanotubes and titanic acid nanotubes, and titanic acid nanotubes and TiO2 nanotubes / nanorods containing embedding E nanoparticles can be achieved in high efficiency and low-cost.

The invention relates to the field of lithium ion batteries, and discloses low-water-absorption lithium titanate, a preparation method thereof, a negative pole piece, a lithium battery and electric equipment. According to the invention, the specific water-resistant polymer protective layer is added on the surface of the lithium titanate material, so that the adsorption to moisture is reduced, the requirement on the humidity of the environment is reduced, and the lithium titanate battery manufacturing process environment is favorably achieved. The prepared lithium titanate pole piece is coated with the protective film, so that the side reaction between the electrolyte and the pole piece after the battery is manufactured in the later period can be reduced, and the gas production problem of the lithium titanate battery can be relieved. The polymer coated protective film on the surface of the lithium titanate material can form a protective layer similar to an SEI (solid electrolyte interface) film in the subsequent charging and discharging process of the lithium titanate battery, so that the stability of the lithium titanate battery is improved. According to the application of the low-water-absorption lithium titanate, the humidity requirement of the lithium titanate battery manufacturing process can be reduced, the lithium titanate battery manufacturing process achievement rate can be improved, the lithium titanate manufacturing process cost and energy consumption can be reduced, and large-scale manufacturing is easy.

The invention relates to a phosphate positive electrode active material based on green cyclic utilization and a preparation method and application thereof, and belongs to the field of secondary batteries. The invention synthesizes a phosphate positive electrode active material LiFex1Nbx2Mgx3Tix4PO4 / D1D2 based on green cyclic utilization, wherein x < 1 > lt is more than or equal to 0.90; 1, 0 < = x2lt; 0.05, 0 < = x3lt; 0.05, 0 lt; x4lt; 0.05, D1 and D2 are respectively a first conductive coating layer and a second conductive coating layer, the D1 conductive coating layer is a nitrogen-sulfur-boron doped composite carbon layer based on an organic framework, and the D2 conductive coating layer is a fast ion conductor of lithium. The phosphate positive electrode active material based on green cyclic utilization is prepared by using the alkaline sodium borohydride aqueous solution to remove aluminum skimmings and a compounding process, so that the raw material utilization rate is greatly improved, and the environment bearing pressure is greatly reduced. Through the design of the composite doped conductive layer, the cycle stability, the rate capability and the high and low temperature performance of the phosphate-based positive electrode material are greatly improved, and the phosphate-based positive electrode material has a relatively good market prospect.

The present invention relates to a lithium-titanium complex oxide, a preparation method thereof, and a lithium secondary battery comprising the same and, more specifically, to a lithium-titanium complex oxide which maintains appropriate pores within particles, and which is prepared by adding a pore inducing material in the wet-milling step to adjust sizes of primary particles of the lithium-titanium complex oxide, a preparation method thereof, and a lithium secondary battery comprising the same. Since a lithium-titanium complex oxide having reduced sizes of primary particles, the lithium-titanium complex oxide according to the present invention shortens a moving distance of lithium ions by adding the pore inducing material, diffusion rate of the lithium ions is increased. Thereby, a battery comprising the lithium-titanium complex oxide according to the present invention exhibits excellent output characteristics by having a structure favorable to electron transport.

The present invention provides a sodium battery positive electrode material, the chemical formula of the sodium battery positive electrode material is xNaMBO3.yNa2Ti3O7.zNa3V2(BO3)3 / C, where the molar ratio of x, y and z is 0.94-0.96:0.02-0.03:0.02-0.03, M is Fe and Mn, the molar ratio of Fe and Mn is 8-9:1-2, and the mass fraction of carbon in the sodium battery positive electrode material is 1.2%-1.5%. The sodium battery positive electrode material provided by the present invention has high capacity, high voltage platform, stable structure, high cycle performance, and its manufacturing method is simple, low cost, and short process flow.

The invention relates to a preparation method and application of chromium-doped sodium titanate with high cycle stability, the chromium-doped sodium titanate is formed by solid-phase sintering of Na2CO3, nano TiO2 and Cr2O3, and optimized Cr-Na2Ti3O7 has excellent cycle stability; the preparation method comprises the following steps: taking a certain amount of Na2CO3, nano TiO2 and Cr2O3 in a corresponding proportion, adding a small amount of isopropanol, and carrying out ball milling in a ball milling instrument for 5-8 hours; completely drying in a drying box, and putting the dried product into a tubular furnace; in a closed atmosphere of high-purity argon, carrying out solid-phase sintering for 10-12 hours by adopting a step-by-step calcination method, and naturally cooling to room temperature; when the material is used as a negative electrode of a sodium ion battery, the coordination environment of sodium ions can be changed, an interlayer Ti-O bond is optimized so as to optimize an interlayer structure, the irreversible capacity generated by Na2Ti3O7 in the charge-discharge cycle process is obviously reduced, and the cycle stability and the rate performance of the battery are improved; the preparation method has important significance for developing a high-performance negative electrode material of the sodium-ion battery and improving the performance of the sodium-ion battery.

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.

A halogenated all-solid-state battery material and a preparation method and application thereof are provided. A general chemical formula of the halogenated all-solid-state battery material is AxMyXzYb, wherein A contains Li or Na; M contains one or more of Mg, Al, Si, P, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Zr and Nb; X contains one or more of F, Cl, Br and I; Y contains O and / or S; and wherein 1≤x≤4, 0.5≤y≤1, 3≤z≤8, and 0≤b≤3. The material has good ionic conductivity, variable valence of M cation and deformability, which enables the material to meet the various requirements as a positive electrode, a negative electrode and a solid electrolyte of an all-solid-state battery and have excellent electrochemical performance.

The invention belongs to the technical field of lithium ion batteries, and particularly relates to a modified lithium iron manganese phosphate material as well as a preparation method and application thereof. The preparation method comprises the following steps: dissolving a hydrophilic carbon source and malic acid in a first solvent to obtain a solution A; dissolving a manganese source, an iron source, a lithium source and a phosphorus source in a second solvent to obtain a solution C, and carrying out hydrothermal treatment on the solution C to obtain a solution B; mixing the solution A and the solution B, and carrying out ultrasonic spray atomization treatment, drying treatment and first heat treatment to obtain a lithium ferric manganese phosphate core material; and mixing the lithium iron manganese phosphate core material, a surfactant and titanium dioxide, and carrying out second heat treatment on the obtained mixture to obtain the modified lithium iron manganese phosphate material. The lithium manganese iron phosphate precursor solution is prepared by a hydrothermal method, and then the precursor solution and the solution containing the hydrophilic carbon source and the malic acid are subjected to ultrasonic spray pyrolysis treatment, so that the obtained modified lithium manganese iron phosphate material is good in processability and has remarkably improved cycle performance.

The invention belongs to the technical field of lithium battery materials, and particularly relates to a method for synthesizing nano lithium titanate, which comprises the following steps: mixing an oxalic acid solution with scrapped denitration catalyst powder, and filtering, washing and drying to obtain acid leaching residues after the reaction is finished; alkali liquor and the acid leaching residues are mixed and then react in a closed reaction kettle, and after the reaction is finished, solid titanate powder is obtained through filtering, washing and drying; the method comprises the following steps: heating and mixing an acid solution and solid titanate powder, cooling, filtering, washing and drying to obtain metatitanic acid powder; adding metatitanic acid powder, a lithium source, deionized water and ball milling balls into a ball milling tank, and drying after ball milling to obtain a lithium titanate precursor; and roasting the lithium titanate precursor in air, and grinding to obtain the lithium titanate powder. According to the method, the nano lithium titanate is synthesized by taking metatitanic acid obtained by resource recovery of the waste denitration catalyst as a titanium source, the reaction process speed is high, the product purity is high, the cost can be effectively saved, mining of mineral resources is effectively reduced, energy is saved, carbon is reduced, and the method has the advantages of environmental protection and green development.

The present invention discloses a high oxygen vacancy titanate nanomaterial and a preparation method thereof, which belongs to the technical field of nanomaterial preparation. Titanium silicon carbide is mixed with an alkaline solution containing potassium fluoride, and oxygen is continuously introduced while heating in an oil bath to obtain a high oxygen vacancy titanate nanomaterial. The high oxygen vacancy content gives the material more potassium storage sites, effectively improving the diffusion rate and storage capacity of potassium ions. In addition, the increase in the lamellar tissue distance in the structure allows potassium ions to shuttle more freely between nanolayers, greatly enhancing the electrochemical properties of the material. This excellent lamellar structure also provides more channels for electron conduction, effectively promoting the rapid transfer of electrons inside and outside the active particles, thereby further improving the rate performance of the electrode material. The high oxygen vacancy titanate nanomaterial has broad application prospects in the fields of sustainable energy, energy storage devices, and electric vehicles.

The disclosure relates to barium strontium titanate, and to a barium strontium titanate fine particle powder, characterized in that the average primary particle size of the primary particles is 50 nm or less, and the difference between the theoretical lattice constant and the lattice constant is 0 Å or more and 0.0080 Å or less. The disclosure also relates to a method for producing a barium strontium titanate fine particle powder, characterized in that a titanium raw material is mixed with an alkaline aqueous solution, a neutralization reaction is performed to obtain a hydrous titanium hydroxide slurry, the slurry is washed with water and heated, the slurry is added to a mixed solution of an aqueous strontium solution and an aqueous barium solution, and a wet reaction is carried out at a temperature range of 100 to 300°C, followed by washing the slurry with water and drying the slurry.

A porous particulate nanocomposite material comprising, as determined by X-ray diffraction: carbon; an orthorhombic CaTiO3 crystalline phase; and, a rhombohedral MgTiO3 crystalline phase. Based on the total number of atoms in the nanocomposite material and as determined by energy dispersive X-ray spectroscopy (EDX): the atomic concentration of carbon (C) is from about 1 to about 5 atom % (at. %); the atomic concentration of titanium (Ti) is from about 20 to about 35 at. %; the atomic concentration of magnesium (Mg) is from about 5 to about 15 at. %; and, the atomic concentration of calcium (Ca) is from about 5 to about 15 at. %.

A process for the preparation of non-fibrous alkaline titanates comprising the steps of: melting alkaline titanate in a furnace at a temperature ranging from 1300° C. to 1500° C. to form a molten product; cooling said molten product by placing it in contact with a material having a temperature equal to or lower than 15° C.

The invention relates to a doped sodium trititanate composite material as well as a preparation method and application thereof, and belongs to the technical field of sodium ion batteries. The doped sodium trititanate composite material comprises: a matrix composed of sodium titanate, aluminum doped in the surface region of the sodium titanate and magnesium doped in the bulk phase region of the sodium titanate; the chemical formula of the matrix is Na < 2-2x > Mg < x > Ti < 3-0.75 y > Al < y > O < 7 >, x is more than or equal to 0.01 and less than or equal to 0.05, and y is more than or equal to 0.002 and less The carbon conductive layer is formed by amorphous carbon and coats the surface of the substrate; and the electrolyte layer is composed of Na3PS4 and coats the surface of the carbon conductive layer. From the perspective of material thermodynamics, phase change is effectively inhibited by Al / Mg doping; in the aspect of interface chemistry, Na3PS4 is adopted to stabilize a solid electrolyte interface; and meanwhile, the preparation process is optimized from the aspect of process compatibility, so that the preparation of the doped sodium trititanate composite material with excellent performance is realized.

The invention provides a positive electrode active material and a preparation method and application thereof, the positive electrode active material comprises a chemical composition Lim1 (Nia1Cob1Mnc1Ald1Zre1Bf1Tig1Xh1) O2, 0.9 < m1 < 1.05, 0.8 < a1 < 0.96, 0.02 < b1 < 0.1, 0.02 < c1 < 0.1, 0 < d1 < 0.02, 0 < e1 < 0.005, 0 < f1 < 0.01, 0 < = g1 < 0.002, 0 < h1 < = 0.003, a1 + b1 + c1 + d1 + e1 + f1 + g1 + h1 = 1, and X comprises at least one of Sr, Y, W and Nb; and the porosity of the positive electrode active material satisfies a specific relational expression 2. When the positive electrode active material is applied to the lithium ion battery, the cycle performance and the high-temperature storage performance of the battery can be effectively improved.

The invention discloses a graphite composite material and a preparation method thereof, a negative plate, an electrochemical device and electronic equipment. The graphite composite material sequentially comprises an inner core, a first coating layer and a second coating layer from inside to outside, the inner core comprises porous graphite and a silicon simple substance, and at least part of the silicon simple substance exists in pores of the porous graphite; the first coating layer is a carbon coating layer; the second coating layer comprises lithium titanate; the silicon elementary substance accounts for 18%-27% of the mass of the graphite composite material; the mass percent of the lithium titanate in the graphite composite material is 0.5%-1.2%; the specific pore volume of the limited pores of the graphite composite material is 0.09 cm < 3 > / g to 0.21 cm < 3 > / g, and the limited pores refer to pores with the pore diameter of 0.2 nm to 5 nm. When the graphite composite material provided by the invention is applied to the lithium ion battery, the lithium ion battery has both capacity and long circulation.