510results about How to "Improved magnification performance" patented technology

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 relates to the field of solid-state batteries, in particular to a halide electrolyte, a preparation method and a solid-state battery. The halide electrolyte comprises a tin element, and the chemical formula of the halide electrolyte is Li2Zr < 1-x > Sn < x > Cl < 6-4x > O < 2x >, and x is less than or equal to 0.3. Through tin-oxygen co-doping, force is exerted at the same time from the two aspects of crystal structure (bulk phase) and interface chemistry, the key problems of ionic conductivity, electrochemical stability, interface compatibility and the like are cooperatively solved, the cost and the process are perfectly considered, and an all-solid-state battery electrolyte solution with a great commercialization prospect is provided.

The invention provides a silicon-carbon composite negative electrode material, a preparation method of the silicon-carbon composite negative electrode material, a lithium ion battery negative electrode plate containing the silicon-carbon composite negative electrode material and a lithium ion battery, and relates to the technical field of lithium ion batteries. The silicon-carbon composite negative electrode material comprises a porous carbon skeleton, silicon distributed in internal pores of the porous carbon skeleton, and a functional interface layer covering the outer surface of the skeleton, wherein no free silicon elementary substance exists on the outer surface of the porous carbon skeleton, and the functional interface layer comprises a metal fluoride passivation layer formed by reacting metal elements doped in the carbon skeleton with a fluorine-containing etching agent; and the hybrid electrolyte coating layer is formed by reacting an oxygen-containing or nitrogen-containing functional group grafted on the surface of the carbon skeleton with a fluorine-containing etching agent. According to the technical scheme, the stable interface layer with passivation protection and ion conduction functions can be constructed in situ while high-activity silicon on the surface is removed, so that the first coulombic efficiency, the cycling stability and the rate capability of the battery are remarkably improved, side reactions are reduced, and the safety of the battery is improved.

The application discloses a synthesis method of a large single-crystal sodium-ion battery layered oxide positive electrode material, and comprises the following steps: (1) weighing metal oxides containing transition metal elements, transferring to a device with mixing functions, uniformly mixing, and obtaining a metal oxide mixture; (2) adding acid to the metal oxide mixture, fully mixing, and completing an acid treatment process; (3) adding alkali to the mixture after acid treatment, fully mixing; (4) transferring the mixture obtained in the step (3) to a calcining furnace, high-temperature calcining, and obtaining a layered oxide. The acid treatment process is introduced, the surface of the metal oxide forms a defect structure under the action of the acid, and the defect structure is more beneficial to the formation of strong interaction between each component of the metal oxide and between the metal oxide and sodium-containing alkali, so that a larger single-crystal layered oxide structure is finally formed, and the specific capacity, rate performance and cycle performance are excellent.

The present disclosure provides a composite pre-lithium thin film and a preparation method thereof and related applications. The composite pre-lithium thin film comprises a loading layer having a first surface and a second surface opposite to the first surface, and the material of the loading layer comprises multi-walled carbon nanotubes; a lithium pouring layer arranged on the first surface of the loading layer; and a resistance buffer layer arranged on the second surface of the loading layer, and the material of the resistance buffer layer comprises single-walled carbon nanotubes and polyvinyl butyl, wherein the mass percentage of the single-walled carbon nanotubes is 0-80 wt.%. The scheme provided by the present disclosure can effectively improve the cycle performance and rate performance of lithium ion batteries, and solve the problems of uncontrollable pre-lithiation rate and easy breaking of lithium metal strips.

The invention provides a carbonaceous material and a preparation method thereof, and a negative pole piece, a secondary battery and an electric device containing the carbonaceous material, after the carbonaceous material is subjected to an adsorption test for 100 hours by adopting water vapor under the conditions of 25 DEG C and 100% RH constant temperature and humidity, the adsorption mass of the water vapor is recorded as A, the initial mass of the carbonaceous material is recorded as B, and A / B is greater than or equal to 0.13 and less than or equal to 0.50. The capacity and the first coulombic efficiency of the carbonaceous material can be improved at the same time.

The application provides a positive plate preparation method based on electrolyte moisture control and a battery. The core rule that "moisture of solid-state electrolyte wet powder is a key factor affecting the moisture of the positive plate" is first determined, and the long-standing error cognition in the industry that "controlling the total moisture of the slurry is enough" is corrected, providing a scientific theoretical basis for moisture control. By detecting three indexes before the slurry is used, the moisture of the positive plate can be accurately predicted whether it will exceed the standard, and the risk of scrapping the whole batch of positive plates is fundamentally avoided. By strictly controlling the moisture of the positive plate, the side reactions in the battery are effectively reduced, the capacity retention rate, rate performance and cycle life of the battery are improved, and the safety hazards such as swelling and thermal runaway caused by excessive moisture are reduced.

This invention relates to a boron-doped multi-element polyanionic sodium-ion battery cathode material and its preparation method, comprising the following steps: [The method involves] mixing Na₄Fe₂O₃ with... 3‑X B X (PO4) 2‑Y (SiO4) Y The stoichiometric ratio of P2O7 is determined by adding ferrous source, boric acid, sodium source, phosphorus source, and silicon source to water, followed by the addition of carbon source and mixing thoroughly to obtain a mixed slurry; wherein 0.2≤X≤0.5, 0<Y≤1; the mixed slurry is then ground to obtain a sand-milled slurry; the sand-milled slurry is dried to obtain precursor powder; under a protective atmosphere, the precursor powder is sintered at 450~550℃ to obtain boron-doped multi-element polyanion sodium-ion battery cathode material. The introduction of boron and silicon elements in this invention helps reduce raw material costs, improve the electrochemical performance of the material, especially enhancing the structural stability, rate performance, and cycle life of the cathode material, and also lowers the sintering temperature, meeting the requirements for cost reduction and efficiency improvement.

This invention belongs to the field of sodium-ion batteries, and relates to a fluorophenylphosphonate, its preparation method, and its application in sodium-ion batteries. The fluorophenylphosphonate includes di(trifluoroisopropyl)phenylphosphonate or di(hexafluoroisopropyl)phenylphosphonate; the preparation steps are as follows: using fluoroalcohol and phenylphosphonyl dichloride as raw materials, triethylamine as an acid-binding agent, and diethyl ether as a reaction solvent, the fluorophenylphosphonate is prepared by a condensation substitution reaction. Sodium-ion batteries prepared using fluorophenylphosphonate exhibit high ionic conductivity and an electrochemical stability window. This phosphonate additive preferentially decomposes at the electrode interface, inducing the formation of a thin, dense, uniform electrode-electrolyte interface phase rich in NaF inorganic components, and giving the electrolyte excellent flame-retardant properties. Sodium-ion batteries assembled with positive electrode materials exhibit good rate performance and cycle stability, with a cycle life exceeding 5000 cycles at room temperature. Simultaneously, this electrolyte also exhibits excellent cycle performance at a high temperature of 60°C.

This invention belongs to the technical field of lithium-ion battery cathode materials, specifically relating to a sulfonic acid-based organic polymer, a sulfonic acid-based organic polymer / carbon nanotube composite material, its preparation method, and its application. The sulfonic acid-based organic polymer is prepared by a dehydration condensation reaction of 2,5-diaminobenzenesulfonic acid and hexaazabenzophenanthrene hexacarboxylic acid trianal. When used as a lithium-ion battery cathode material, it exhibits high specific capacity and excellent cycle stability, overcoming the solubility problem of organic cathode materials in electrolytes. When the sulfonic acid-based organic polymer is combined with carbon nanotubes and applied to lithium-ion battery cathode materials, battery performance is significantly improved, and the capacity remains stable even after long-term cycling. The synthesis methods of the sulfonic acid-based organic polymer and the sulfonic acid-based organic polymer / carbon nanotube composite material of this invention are simple, have abundant raw material sources, and good reproducibility, making them suitable for industrial production and possessing broad application prospects in the field of lithium-ion batteries.

The application relates to the technical field of batteries, in particular to a hard carbon negative electrode material and a preparation method and application thereof. A preparation method of a negative electrode hard carbon material comprises the following steps: carrying out first heat treatment on a mixture of an organic metal catalyst and biomass activated carbon, introducing a gas-phase carbon source and carrying out second heat treatment to obtain first material, and carrying out carbonization treatment and acid pickling treatment on the first material. The method can improve the capacity and initial efficiency of the hard carbon negative electrode material through cooperation of various steps; the method is simple in process and easy to realize large-scale production.

This invention belongs to the technical field of industrial flue gas purification and solid waste resource utilization, specifically involving hydrogen fluoride adsorbents, their preparation methods and applications, and the application of waste adsorbents as fluoride electrode materials. The invention involves sequentially subjecting decayed oak wood to anaerobic fermentation and vacuum micro-aerobic pyrolysis to obtain a porous biochar carrier; loading a metal precursor onto the porous biochar carrier using an impregnation method to obtain a semi-finished product; and calcining the semi-finished product in a protective gas atmosphere to obtain the hydrogen fluoride adsorbent. The hydrogen fluoride adsorbent provided by this invention exhibits a high adsorption rate for HF, and the saturated waste adsorbent can be reused as a fluoride electrode material, demonstrating excellent cycle stability and rate performance. This invention provides a novel pathway for the functional transformation of biomass waste and the preparation of high-performance energy storage materials, while simultaneously reducing the cost of HF adsorbents, and has broad practical application value.

The application discloses a kind of composite negative electrode material for all-solid-state iron air battery, its negative electrode and battery.The composite negative electrode material is composed of active substance and functional additive;Active substance is iron oxide doped with chemical element M, M is selected from one or more of W, Cr, Ti, Mn, V, Mo, Nb, Zr, Hf, Sn, Sb and Bi;Functional additive includes oxygen ion conductor and perovskite material.The application forms stable ion conductive network in situ during the reduction of iron oxide by doping with specific elements, and constructs multi-level composite conductive structure by combining oxygen ion conductor and perovskite, effectively solves the problem of ion transport collapse caused by phase change during the cycle of conversion-type negative electrode, significantly improves the coulomb efficiency, capacity development and cycle stability of all-solid-state iron air battery.

The present application relates to a kind of in situ low-temperature confined carbonization construction carbon dot enrichment coating layer manganese-based positive electrode material and its preparation method, by accurately coordinating the evolution condition of carbon point carbon source in the mixing system environment of coating process, freezing condition and sublimation and carbonization, realize the whole process synergistic control of carbon point carbon source spatial distribution, ice crystal template state, skeleton construction of controlled conversion of carbon point carbon source and harmful residue removal on the surface of manganese-based positive electrode material, successfully constructed the carbon dot enrichment coating layer of size controllable, density adjustable, ion permeability good and interface combination firm on the surface of manganese-based positive electrode material, to realize the synergistic promotion of manganese-based positive electrode material cycle performance, rate performance and interface stability.

This invention relates to the field of secondary battery technology, specifically to a silicon-carbon composite material, its preparation method, and a lithium-ion battery. The preparation method of the silicon-carbon composite material includes: reacting an organometallic framework ZIF-8 in a saturated metal salt solution and then evaporating and crystallizing it to obtain a metal salt-coated organometallic framework Salt@ZIF-8; pulverizing a silicon-copper alloy precursor and the Salt@ZIF-8 at a mass ratio of 1:0.05-0.7 to obtain a mixed powder; and subjecting the mixed powder to a pyrolysis reaction and acid leaching treatment to obtain the silicon-carbon composite material. The silicon-carbon composite material obtained by this invention exhibits excellent structural stability and electrochemical performance, effectively mitigating the volume expansion of the silicon anode and improving cycle performance and rate performance.

The invention relates to an O2-phase lithium cobalt oxide positive electrode material and a preparation method thereof, and belongs to the technical field of lithium ion batteries. The preparation method comprises the following steps: S1, uniformly mixing a doped metal source, a sodium source and a cobalt source, sintering, and cooling to obtain a P2-phase precursor; s2, uniformly mixing the P2-phase precursor, a lithium source A and the coating layer precursor, sintering, and cooling to obtain an intermediate A; s3, uniformly mixing the intermediate A and a lithium source B, sintering, and cooling to obtain an intermediate B; and S4, uniformly mixing the intermediate B and a lithium source C, sintering, cooling, washing and drying to obtain the O2-phase lithium cobalt oxide positive electrode material. The O2-phase lithium cobalt oxide positive electrode material with low residual sodium, high structural stability and excellent interface coating performance is prepared through a method of combining gradient ion exchange, gradient temperature control, gradient atmosphere regulation and control and synchronous in-situ coating.

The application discloses a negative pole piece and a lithium ion battery, and relates to the technical field of batteries, and specifically discloses a negative pole piece and a lithium ion battery. The negative pole piece comprises a current collector, a first coating layer and a second coating layer which are stacked on at least one side of the current collector; the first coating layer and the second coating layer each comprise a negative active material, a first binder, a second binder, a first conductive agent and a second conductive agent; and the preparation of the negative pole piece satisfies the following conditions: 2≤C2 / C1≤4 and 1.05≤X / Y≤1.25, wherein C1 and C2 are the mass proportions of the first conductive agent in the first coating layer and the second coating layer respectively, and X and Y are the solid contents of the first coating layer slurry and the second coating layer slurry respectively. According to the application, the solid content of the slurry, the proportions of different active materials and conductive agents are designed and controlled in the double-coating pole piece, and the designed proportions satisfy a certain functional relationship, so that the ion conductivity of the battery can be effectively improved while the high conductivity of the pole piece is maintained, the direct-current internal resistance of the pole piece in the charging and discharging process is reduced, the rate charging and discharging performance is improved, and the lithium precipitation window is widened.

The invention provides a composite positive plate, a preparation method thereof and a battery, and belongs to the technical field of batteries. The interface conductive layer is arranged on at least one side of the positive electrode active material layer, and the interface conductive layer comprises conductive filler and an elastic matrix. According to the composite positive plate, the interface conductive layer with conductivity, flexibility and elasticity is arranged on at least one side of the positive active material layer, so that when the composite positive plate is applied to the battery and the interface conductive layer is close to one side of the diaphragm, not only can the interface impedance be reduced, but also the wettability of electrolyte on the positive active material layer can be improved; when the interface conducting layer is close to one side of the shell, the positive electrode active material layer can be better protected, extrusion damage of the shell to the positive electrode active material layer is reduced, the interface conducting layer can serve as a current collector, the electrochemical performance of the battery is improved, and the interface conducting layer can adapt to volume expansion of the composite positive plate in the charging and discharging process of the battery and improve the cycle performance of the battery.

The invention relates to the technical field of lithium battery positive electrode material preparation, in particular to coated doped type lithium manganese iron phosphate gradient temperature control preparation equipment and method.The equipment comprises five temperature control bins arranged side by side, a sintering bin, a vertical flow guide plate, a unique temperature control gas inlet assembly and the like work cooperatively, the temperature control gas inlet assembly can flexibly adjust the gas state, and the temperature control gas inlet assembly can control the temperature of the lithium manganese iron phosphate; the preparation method comprises the following steps: firstly, mixing a lithium source, a manganese source and the like with a specific composite carbon source, and performing spray drying to obtain precursor particles; according to the preparation method, the defects of a traditional preparation technology in the aspects of temperature control and coating forming are overcome, accurate gradient temperature control can be achieved, the temperature uniformity can be improved, the coating effect can be optimized, and the preparation method is suitable for industrial production. And the performance of the lithium manganese iron phosphate positive electrode material is remarkably improved.

The invention relates to the technical field of lithium ion batteries, in particular to a composite positive electrode material and a preparation method thereof, a lithium ion battery and electric equipment. The invention provides a preparation method of a composite positive electrode material, which comprises the following steps: mixing a bulk phase dopant, a lithium source and a ternary precursor to obtain a mixture I, and respectively sintering at 815-830 DEG C for 12-14 hours and at 760-770 DEG C for 8-10 hours to obtain a sintered material I-1 and a sintered material I-2; a first coating agent and a second coating agent are mixed with the sintered material I-1 and the sintered material I-2 respectively and then coated, and a sintered material II-1 and a sintered material II-2 are obtained; and mixing the sintered material II-1 and the sintered material II-2 to obtain the composite positive electrode material. According to the invention, the bulk phase dopant and the doped ternary precursor core layer are firstly added, then the first coating agent and the second coating agent are added, and the surface functional layer is synthesized, so that the composite positive electrode material has both high capacity and high cycle stability under the synergistic effect of the bulk phase dopant and the doped ternary precursor core layer.

The invention relates to the technical field of sodium-ion batteries, in particular to a sodium-ion battery positive electrode material and a preparation method thereof. The sodium ion battery positive electrode material is Ti and Cl doped Na4VMn (PO4) 3, and the molar ratio of Na to Ti in the sodium ion battery positive electrode material is 4: (0.05-0.1); the molar ratio of Na to Cl is 4: (0.05-0.1). According to the sodium-ion battery positive electrode material provided by the invention, a titanium element and chlorine element synergistic co-doping mode is adopted, so that the ginger-Taylor distortion caused by manganese ions in the charging and discharging process can be inhibited, the lattice stress can be reduced, and the stability of the material structure can be enhanced; meanwhile, the dissolution of manganese under a high-rate cycle condition can be inhibited, and the loss of active substances and the side reaction of electrolyte are reduced, so that the electrochemical stability and the structural integrity of the electrode material are improved, and the sodium ion battery containing the positive electrode material has relatively high specific capacity, excellent rate capability and cycle stability.

The application provides a preparation method of a binder, the binder is prepared from modified polyacrylonitrile through a cross-linking reaction and post-treatment; the modified polyacrylonitrile is a hydrolysis product of polyacrylonitrile, and the cross-linking agent of the cross-linking reaction is epichlorohydrin. The application also provides corresponding binders, lithium ion battery negative electrodes, lithium ion batteries and electrochemical devices. The binder of the application can significantly improve the cycle stability and rate performance of the battery, and the effect is particularly significant for a silicon negative electrode with large volume expansion. The preparation process of the binder of the application has the advantages of simple operation and low cost, and is easy to realize industrial production.

The application relates to a preparation method of a sulfonated asphalt carbon@BiOCl sodium ion battery negative electrode composite material. Bi(NO3)3.5H2O and A are dissolved in ethylene glycol, 3-aminopropyl methoxysilane is added into the ethylene glycol, and stirring is conducted to form a uniform suspension; A is SnCl4.5H2O, SnCl4 or SnCl2; sulfonated asphalt is added into the suspension, and magnetic stirring is conducted; then the suspension is moved into polytetrafluoroethylene and is placed into a high-pressure reaction kettle for constant temperature treatment at 160-200 DEG C for 10-24h; after the reaction kettle is cooled to room temperature, centrifugal separation is conducted, and drying is conducted; 4) the sample is subjected to constant temperature treatment at 600-1000 DEG C for 1-3h in a tubular furnace in an inert atmosphere, and the temperature is reduced to room temperature. Advantages are that the sodium ion battery negative electrode composite material with high performance is prepared through a simple one-step hydrothermal method, and the sodium ion battery negative electrode composite material has high specific capacity and excellent rate performance.

The application discloses a negative active material, a preparation method of the negative active material, a secondary battery and an electric device, and the negative active material comprises a silicon-based material, a carbon coating layer arranged on the surface of the silicon-based material, and a titanium oxide layer arranged on the surface of the carbon coating layer, and the electron paramagnetic resonance spectrum of the negative active material has a characteristic peak at g=2.002-2.004. The application sets the titanium oxide layer containing oxygen defects on the surface of the carbon-coated silicon-based material, improves the rate performance on the basis of improving the initial coulomb efficiency and the cycle performance, and has a wide application prospect.

A negative electrode for a rechargeable lithium battery and a rechargeable lithium battery including the same are provided. The negative electrode includes: a negative electrode current collector including a carbon layer and a silicon layer, the carbon layer including a first porous substrate and a carbon-based material present inside the first porous substrate, and the silicon layer including a second porous substrate and a silicon-based negative electrode active material present inside the second porous substrate; and a negative electrode active material layer disposed on a surface of the negative electrode current collector and including a negative electrode active material.

The invention provides an organic-inorganic hybrid solid-state polymer electrolyte coated high-nickel positive electrode material as well as a preparation method and application thereof, and relates to the technical field of all-solid-state lithium batteries. The high-nickel positive electrode material coated with the organic-inorganic hybrid solid polymer electrolyte comprises an inner core and an organic-inorganic hybrid coating layer coated on the surface of the inner core, the inner core is made of a high-nickel positive electrode material; the organic-inorganic hybrid coating layer comprises a ring-opening copolymer of maleic anhydride and 1, 3-dioxolame, and Li3PO4 nanocrystals are embedded into the ring-opening copolymer of maleic anhydride and 1, 3-dioxolame in situ. According to the invention, a flexible and compact coating layer with ionic conductivity is constructed on the surface of the high-nickel positive electrode material, so that the problems of violent interface side reaction, large interface impedance and poor cycling stability existing between the high-nickel positive electrode material and sulfide solid electrolyte are solved; therefore, the electrochemical performance of the material in a sulfide all-solid-state lithium battery is remarkably improved.

The application relates to the technical field of battery materials. Disclosed are a lithium nickel-manganese acid positive electrode material, a preparation method thereof, a positive electrode and a battery. The lithium nickel-manganese acid positive electrode material comprises a base material and a first coating layer and a second coating layer successively coated on the surface of the base material; the chemical general formula of the base material is Li(Li a Ni b Mn c Fe d Sb e )O 4‑x , wherein a+b+c+d+e=2, 0<=x<=0.2, 0<=a<=0.1, 0.4<=b<=0.5, 1<=c<=1.5, 0.1<=d+e<=0.4; the first coating layer comprises NbTi(PO4)3, and the mass ratio of the first coating layer to the base material is 0.1-5:100; the second coating layer comprises a carbon material, and the mass ratio of the second coating layer to the base material is 0.1-5:100. The lithium nickel-manganese acid positive electrode material provided by the embodiment of the application has excellent electrochemical performance.

The present application relates to the technical field of electrochemistry, and in particular to a fast-charging numerical simulation method, device and medium for thick electrodes of lithium ion batteries, the method comprising: constructing an electrochemical model of a lithium ion battery based on a pseudo two-dimensional model; loading basic parameters of the lithium ion battery, spatially discretizing according to the battery structure, and initializing an array of physical quantities required for simulation; using a Bayesian optimization algorithm, determining the charge-discharge curve of the lithium ion battery based on experiments, and calibrating the kinetic parameters of the battery cell; switching the charge-discharge mode according to the state of the lithium ion battery, performing cycle simulation, outputting simulation data, and completing fast-charging numerical simulation. The method overcomes the problems of the prior art, such as the inability of the pseudo two-dimensional model to accurately simulate the low-temperature fast-charging process of thick electrodes, the lack of an efficient and accurate method for obtaining kinetic parameters, and the difficulty in predicting battery aging caused by SEI growth.

This invention provides an electropolymer-modified aluminum current collector, its preparation method, and its application, relating to the field of aluminum foil current collector technology. By modifying the current collector surface, it primarily addresses the interface problem between the current collector and the active material, thereby improving the performance of lithium-ion batteries. This invention uses an aluminum foil current collector as the anode, a graphite plate as the cathode, and an acidic solution of a conductive polymer monomer as the electrolyte. Anodizing electropolymerization is performed using a constant current or constant voltage method, followed by washing and drying to obtain the electropolymer-modified aluminum current collector. The conductive polymer monomer is at least one of aniline, thiophene, and pyrrole; the concentration of the conductive polymer monomer in the electrolyte is 0.1-1.0 mol / L; and the polymerization time is 5-10 min. This invention effectively reduces the contact resistance between the current collector and the active material, improves the bonding strength between the coating and the substrate, and enhances the corrosion resistance of the current collector, showing promising application prospects.

The invention provides a preparation method of a high-compaction high-capacity lithium iron phosphate material, which comprises the following steps: (1) mixing polyvinyl alcohol, iron phosphate, a lithium source, a carbon source and water to obtain slurry A; mixing iron phosphate, a lithium source, a carbon source and water to obtain slurry B; (2) performing spray drying on the slurry A, and performing low-temperature sintering to obtain a black material C; performing spray drying on the slurry B, and performing high-temperature sintering to obtain a black material D; and (3) mixing the black material C and the black material D, crushing, adding barium titanate, carrying out ball milling, and drying to obtain the lithium iron phosphate material. The polyvinyl alcohol is partially acetylated modified polyvinyl alcohol. The sintering temperature is reduced by adding the modified polyvinyl alcohol to prepare the compact lithium iron phosphate material with smaller particle size, and the lithium iron phosphate material and the lithium iron phosphate material obtained by high-temperature sintering form grading of large and small particles, so that the compaction density of the lithium iron phosphate is improved.