72results about How to "Increase compaction density" patented technology

The invention relates to a method for preparing a lithium iron phosphate / carbon composite material of a lithium ion battery, which belongs to the technical field of lithium ion batteries. The method for preparing the lithium iron phosphate / carbon composite material of the lithium ion battery comprises the following steps of: 1) preparing a suspending graphene-dispersed aqueous solution system, namely, crushing graphite to 1 to 5 microns, adding the crushed graphite into distilled water or purified water, adding 0.1 to 5 percent of surfactant, heating with stirring the mixed solution to 180 to 250 DEG C in a sealing way, performing stirring for 2 to 6 hours and reducing the temperature; 2) crushing lithium iron phosphate to the particle size of 1 to 5 microns, adding the crushed lithium iron phosphate into the distilled water or the purified water, adding with stirring 0.01 to 1 percent of coupling agent, performing uniform stirring, adding the graphene-dispersed aqueous solution, and performing stirring and filtration; and 3) vacuum-drying solid powder obtained by the filtration, and calcinating the dried solid powder for 2 to 12 hours to obtain the graphene-coated lithium iron phosphate cathode material. The method has the advantages of simple process, high material performance, high conductivity, high bulk density, high compacted density and the like.

This invention discloses a sodium-ion battery cathode material, its preparation method, and a sodium-ion battery. The preparation method of the sodium-ion battery cathode material includes the following steps: adding a sodium source, an iron source, a phosphorus source, a carbon source, and an interface segregation regulator to water and mixing them to obtain a precursor slurry; milling the precursor slurry to reduce its D... 50 A fine slurry with a particle size ≤1μm is obtained; the fine slurry is spray-dried to obtain a secondary particle precursor; the secondary particle precursor is pre-sintered under an inert atmosphere to enrich the interfacial segregation regulator on the particle surface and grain boundary region, forming a pre-sintered precursor; the pre-sintered precursor is sintered under an inert atmosphere to obtain a sodium-ion battery cathode material. The method of this invention can prepare a sodium-ion battery cathode material with excellent electrochemical performance and high flat density.

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.

The invention provides a composite solid positive electrode material and a preparation method thereof, a lithium ion battery and electric equipment, and relates to the field of lithium ion batteries. The composite solid positive electrode material comprises a positive electrode material and an organic elastic sphere which are uniformly mixed, the positive electrode material comprises an inner core, a metal compound coating layer and a boride coating layer, wherein the metal compound coating layer and the boride coating layer are sequentially arranged on the surface of the inner core; the raw materials of the organic elastomeric sphere comprise a hydrocarbon derivative monomer, an alkenyl monomer, an emulsifier, an oxidant and a solvent. The organic elastic sphere solves the problem of untight interface contact caused by volume change in the charging and discharging process of the solid-state battery positive electrode material; the inner core of the organic elastic sphere has certain rigidity, and the shell has high elasticity, so that the organic elastic sphere can be used as a rigid framework support and an elastic support to always keep close contact with the surface of a positive electrode material.

The application discloses a positive electrode material and a preparation method and application thereof, and the preparation method comprises the following steps: mixing iron phosphate, a carbon source, a sodium source and water to prepare a slurry; the mixed iron phosphate contains phosphate and pyrophosphate or phosphate and dihydrogen phosphate; the carbon source contains citric acid; the prepared slurry is grinded to obtain a fine slurry; the fine slurry is sprayed and dried to obtain a solid precursor; and the solid precursor is sintered to obtain the positive electrode material. By controlling the reaction parameters, the mixed iron phosphate containing pyrophosphate or dihydrogen phosphate is synthesized, the amount of citric acid in the subsequent process is reduced, the pore generation rate is reduced, the material compaction density is improved, the method is simple and reliable, and the application prospect is good. The prepared positive electrode material has high specific capacity and high compaction density, and is suitable for preparing a positive electrode of a sodium ion battery.

The invention discloses a dry-method lithium supplement positive electrode material and a preparation method thereof, a positive electrode membrane and a preparation method thereof, and a lithium ion battery, and belongs to the technical field of lithium batteries. The dry-method lithium supplement positive electrode material comprises a positive electrode active material, a conductive additive, a polymer binder and Li6WO6, based on 100% of the total mass of the positive electrode active material, the conductive additive and the polymer binder, the mass percentage of the positive electrode active material is 80-85%; the mass percent of the conductive additive is 5-10%; the mass percent of the polymer binder is 0.5-5%; and the mass of Li6WO6 is 5-9% of the total mass of the positive electrode active material, the conductive additive and the polymer binder. When the dry-method lithium supplementing positive electrode material is used for carrying out dry-method lithium supplementing on a lithium ion battery, Li6WO6 is not easy to bond and agglomerate, the stability is high, and the lithium supplementing effect is good; the lithium ion battery containing the dry-method lithium supplement positive electrode material has excellent cycling stability and high first-circle specific capacity.

The application provides a pole piece manufacturing system, a pole piece manufacturing method and a secondary battery. The pole piece manufacturing system comprises a piece manufacturing mechanism, a vibration mechanism and a rolling mechanism. The piece manufacturing mechanism is configured to form a pre-drying pole piece. The vibration mechanism is arranged downstream of the piece manufacturing mechanism. The vibration mechanism is configured to perform vibration treatment on the pre-drying pole piece. The rolling mechanism is arranged downstream of the vibration mechanism. The rolling mechanism is configured to perform rolling on the pre-drying pole piece after the vibration treatment. The application effectively improves the packing density of the particles in the pre-drying pole piece through the vibration treatment on the pre-drying pole piece, thereby effectively improving the ultimate compaction density of the pole piece.

This invention relates to a core-shell structured sodium iron phosphate pyrophosphate cathode material, its preparation method, electrode sheet, and battery, belonging to the technical field of methods or devices for directly converting chemical energy into electrical energy. The core-shell structured sodium iron phosphate pyrophosphate cathode material of this invention comprises primary particles, each primary particle including: a core, a sodium iron phosphate pyrophosphate shell layer disposed on at least a portion of the surface of the core, and a carbon coating layer located within the pores and on the surface of the sodium iron phosphate pyrophosphate shell layer; the core includes a NASICON-type sodium-ion inorganic solid electrolyte with an average particle size ≤50nm; the average thickness of the sodium iron phosphate pyrophosphate shell layer is ≤500nm; the chemical formula of the sodium iron phosphate pyrophosphate shell layer is Na₄Fe₂O₃. 3‑ x M x (PO4)2P2O7, 0≤x≤0.9, M is a doped metal element. The core-shell structured sodium iron phosphate pyrophosphate cathode material of this invention combines high solid density, high conductivity and good electrochemical performance.

This invention discloses a waste recycling device for FIBC (Flexible Intermediate Bulk Container) processing, relating to the field of comprehensive environmental utilization of solid waste. The device includes a hollow frame, a hydraulic rod mounted on the hollow frame, and a pressure plate mounted on the hydraulic rod. The equipment continuously feeds FIBC waste into a flattening machine. The pressure plate is automatically triggered by the weight of the waste, achieving a complete automatic cycle of feeding, weighting, triggering, compaction, resetting, and locking, thus improving waste recycling efficiency. When not in operation, the pressure plate is rigidly limited by a limiting mechanism, preventing hydraulic system depressurization or accidental drop. This ensures uniform compaction density of the plastic waste, reducing the mixing and adhesion of plastic and impurities due to insufficient compaction, facilitating subsequent separation of plastic from other components. It also protects core components such as the hydraulic rod and pressure plate, extending equipment lifespan, reducing maintenance costs, and contributing to the resource-based recycling of plastic waste and comprehensive utilization of solid waste.

The application provides a double-coating lithium iron phosphate positive electrode sheet, a preparation method and application thereof. The preparation method comprises the following steps: mixing modified large-particle lithium iron phosphate, modified small-particle lithium iron phosphate, a conductive agent, a binder and a solvent to obtain a first slurry and a second slurry; adopting double-layer slot extrusion coating to coat the first slurry on the surface of a current collector and coat the second slurry on the surface of the first slurry; and drying and rolling to obtain the double-coating lithium iron phosphate positive electrode sheet; the modified large-particle lithium iron phosphate is doped with Ti and Nb, and the modified small-particle lithium iron phosphate is doped with Mg and Al. The application adopts a multi-element doped positive electrode material combined with a double-layer coating preparation method to avoid the shortcomings of LFP materials, improve the rate performance, high-temperature performance and cycle performance of LFP, and has the advantages of simple preparation process and easy industrial production. The prepared positive electrode material and the secondary battery using the same have excellent comprehensive performance, and have a wide application prospect in the field of power batteries.

The invention relates to the technical field of lithium ion batteries, and discloses a ternary positive electrode material and a preparation method and application thereof. The preparation method of the ternary positive electrode material provided by the invention comprises the following steps: S1, mixing a small-particle ternary positive electrode material precursor with a lithium source and a doping agent, carrying out first sintering, cooling and crushing to obtain a small-particle primary sintering product; mixing the large-particle ternary positive electrode material precursor with a lithium source and a doping agent, carrying out primary sintering, and crushing to obtain a large-particle primary sintering product; and S2, mixing the small-particle primary sintering product and the large-particle primary sintering product with a coating agent, and carrying out secondary sintering to obtain the ternary positive electrode material. The ternary positive electrode material prepared by the preparation method provided by the invention is large in compaction density, low in residual alkali content, good in interface stability, and relatively good in capacity and cycling stability, and the electrochemical performance of the ternary positive electrode material under a high-voltage condition is remarkably improved.

The invention provides a negative electrode material and a battery, the negative electrode material comprises an inner core and a coating layer located on at least part of the surface of the inner core, the inner core comprises graphite, the coating layer comprises a polymer, and the negative electrode material comprises at least one of an element N, an element S and an element P; the repose angle of the negative electrode material is theta degrees, the tap density of the negative electrode material is rho g / cm < 3 >, the compaction density of the negative electrode material under the pressure of 5T is T1 g / cm < 3 >, and the negative electrode material meets the formula: M = theta / rho * T1, and M is more than or equal to 105 and less than or equal to 160. According to the negative electrode material provided by the invention, the negative electrode material has high capacity, high compaction density and low expansion performance, and the fast charging performance of the negative electrode material is improved.

The application discloses a preparation method of a polyanionic sodium ion battery positive electrode material, and comprises the following steps: S1, preparation of a precursor solution: a transition metal M source, an acid solution and a complexing agent are mixed and dissolved to form a precursor solution; S2, preparation of a pre-oxidized precursor solution: an oxidizing agent is added to the solution to generate a pre-oxidized precursor solution; S3, preparation of M(OH)x precipitation: a pH value of the pre-oxidized precursor solution is adjusted so that transition metal ions in the solution are precipitated in the form of M(OH)x; S4, preparation of a precursor powder: the M(OH)x precipitation, a sodium source, a phosphorus source and a carbon source are mixed wetly to obtain a precursor slurry; S5, drying of the precursor powder: the precursor slurry is dried and separated to obtain a dried precursor powder; and S6, high-temperature sintering: the precursor powder is sintered at a high temperature to obtain a polyanionic material. The polyanionic sodium ion battery positive electrode material has the characteristics of excellent electrochemical performance, high compaction density and low cost.

This invention provides a high-conductivity, ultrathin carbon layer high-compact lithium iron phosphate processing method, relating to the field of lithium-ion battery material preparation technology. The method includes: firstly, mixing and carbonizing asphalt, phenolic resin, and sodium chloride using wet ball milling; using sodium chloride as a pore-forming template to prepare a first carbon source with a porous structure; then mixing iron phosphate, lithium source, phosphorus source, and titanium citrate as a second carbon source, and adjusting the pH to 8-10 to induce structural changes in titanium citrate to achieve lattice titanium doping; finally, adding the first carbon source to the mixture, followed by grinding, drying, and sintering under an inert atmosphere to obtain the lithium iron phosphate cathode material. This invention effectively solves the problem of low compaction density caused by excessively thick carbon layers through the synergistic effect of dual carbon sources and pH control technology, significantly improving the material's conductivity and ion diffusion rate while achieving high compaction density and excellent electrochemical performance.

Provided are a positive electrode active material, a positive electrode sheet, a battery monomer (10), a battery (400), and an electric device, belonging to the technical field of secondary batteries. The positive electrode active material comprises a lithium-rich manganese-based material and a lithium-containing phosphate, the lithium-rich manganese-based material comprises solid particles and hollow particles, and the hollow particles comprise a shell and a cavity arranged on the inner side of the shell. The rate performance and the volumetric energy density of the battery monomer can be considered.

This invention provides a method for preparing lithium iron phosphate from hydroxyferric phosphate and lithium iron phosphate electrode material. Ferrous sulfate is purified to form a ferrous sulfate solution. Hydrogen peroxide, phosphoric acid, ammonium dihydrogen phosphate solution, and ammonia are added to the ferrous sulfate solution to form a mixed slurry. The mixed slurry is kept at room temperature for a period of time, then washed with water and filtered to form hydroxyferric phosphate precursors with different iron-phosphorus ratios. These precursors are then flash-dried and sintered at high temperature to obtain hydroxyferric phosphate precursors with different iron-phosphorus ratios and specific surface areas. The hydroxyferric phosphate precursors are pulverized and mixed to obtain the finished hydroxyferric phosphate product. High-iron-phosphorus ratio hydroxyferric phosphate and low-iron-phosphorus ratio hydroxyferric phosphate are mixed in a certain proportion and then formulated with lithium phosphate, lithium iron phosphate, and electrode material in a specific ratio, with the addition of a carbon source and additives to form a mixture. The mixture is then subjected to ball milling, sand milling, spray drying, sintering, pulverizing, sieving, batching, and packaging processes to obtain the finished lithium iron phosphate product.

This invention relates to the field of sodium-ion battery technology, specifically disclosing a sodium iron pyrophosphate (NFPP) cathode material, its preparation method, and its application. The preparation method includes: using iron phosphate as the iron source, mixing it with a specific sodium source, phosphorus source, and composite carbon source; adjusting with deionized water; and then performing precision sand milling to control the slurry particle size D50 within 0.30~0.35 μm to ensure uniform elemental mixing; subsequently, spray drying is performed to obtain a precursor with high sphericity and narrow particle size distribution; finally, programmed sintering is carried out under an inert atmosphere to obtain the final product. This invention solves the problems of uneven elemental distribution, impurity phase formation, low material compaction density, and poor electrochemical performance in existing technologies through synergistic optimization of the entire process chain of sand milling-spray drying-sintering. The obtained NFPP material has a high-purity phase structure. The sodium iron pyrophosphate cathode material prepared by the method of this invention can achieve a 0.1C discharge specific capacity of 101 mA·hg. ‑1 The 1C discharge specific capacity can reach 93 mA·hg ‑1 It is suitable for the preparation of high-performance sodium-ion batteries.

The present application relates to the technical field of new energy battery, in particular to a coated ternary material mixed with different particle sizes, a preparation method thereof and a battery; the preparation method comprises the following steps: mixing a nickel-cobalt-manganese precursor and a lithium salt, and then mixing the mixture with a gel solution to obtain a premix; mixing a metal oxide with the gel solution to obtain an oxide coating agent; mixing a carbon source with the gel solution to obtain a carbon coating agent; coating the oxide coating agent on the outside of the premix by using an electrospinning method to obtain an oxide-coated ternary material; coating the carbon coating agent on the outside of the premix by using an electrospinning method to obtain a carbon-coated ternary material; sintering the oxide-coated ternary material and the carbon-coated ternary material; mixing and sintering the sintered oxide-coated ternary material and the sintered carbon-coated ternary material; wherein the particle size of the oxide-coated ternary material is larger than that of the carbon-coated ternary material. The preparation method is simple, has fewer processes, and can shorten the preparation time.

The invention belongs to the field of batteries, and particularly discloses a lithium manganese iron phosphate composite material, a preparation method thereof and a secondary battery containing the lithium manganese iron phosphate composite material. The preparation method comprises the following steps: firstly preparing ferromanganese phosphate containing a special pore-forming agent, and then mixing the ferromanganese phosphate serving as a precursor with raw materials such as a lithium source, a doped metal element M source and a carbon source; the preparation method comprises the following steps: respectively grinding the mixture into large and small particle mixtures with different particle sizes, grinding and mixing the large and small particle mixtures, and carrying out spray drying to obtain an unsintered precursor mixture, and finally carrying out heat treatment sintering on the unsintered precursor mixture twice to obtain the lithium manganese iron phosphate composite material. According to the method disclosed by the invention, the lithium manganese iron phosphate composite material has the advantages of high compaction density, high rate capability, low cost and high gram capacity, and the application prospect of the material is widened.

The application provides a lithium manganese iron phosphate precursor and a preparation method and application thereof. x Fe y M 1‑x‑y PO 7 / 2 , wherein x is 0.5-0.7, y is 0.3-0.5, and M is a doped metal element; the lithium manganese iron phosphate precursor has small particle size, uniform composition and high tap density, can solve the problems of large particle size, low tap density and ammonium component of the lithium manganese iron phosphate precursor, and can reduce the generation of a large amount of ammonia gas during lithium sintering of the precursor, so that the tap density and electrochemical performance of the lithium manganese iron phosphate positive electrode material are significantly improved.

The application provides a method for preparing lithium iron phosphate from iron hydroxyl phosphate and ferrous oxalate. The ferrous sulfate is purified to form a ferrous sulfate solution. Hydrogen peroxide, phosphoric acid, ammonium dihydrogen phosphate solution and ammonia water are sequentially added to the solution to form a mixed slurry. The mixed slurry is heated and kept warm, and then washed with water and filtered under pressure to form an iron hydroxyl phosphate precursor with different iron and phosphorus ratios. The iron hydroxyl phosphate precursor is dried by flash evaporation and sintered at high temperature and then crushed to obtain an iron hydroxyl phosphate precursor with different iron and phosphorus ratios and different specific surface areas. The iron hydroxyl phosphate precursor is crushed and mixed to obtain an iron hydroxyl phosphate product. The high-iron and low-iron ratio iron hydroxyl phosphate is mixed with ferrous oxalate, lithium phosphate, lithium carbonate and ammonium dihydrogen phosphate in a certain proportion, and a carbon source and an additive are added to form a mixture. The mixture is subjected to a series of processes such as ball milling, sand milling, spray drying, sintering, crushing, screening, batching and packaging to obtain a lithium iron phosphate product.

The application relates to the technical field of secondary battery material preparation, and discloses a preparation method of a resin-based coated pitch-based hard carbon composite material, which comprises the following steps: S1, uniformly mixing pitch, sodium nitrite, 1,4-p-phenylenediamine and a catalyst, performing a diazotization reaction, and obtaining aminated pitch; S2, uniformly mixing the aminated pitch and an aldehyde solution, adding a graphene oxide solution and a nitrogen source, uniformly mixing again, adding a phenol solution, performing an oxidation-reduction reaction, forming a heteroatom-doped resin-based hard carbon composite shell outside the aminated pitch-based hard carbon, and obtaining a hard carbon precursor material; and S3, carbonizing the hard carbon precursor material to obtain a hard carbon composite material. Through the technical scheme, the problem that the first discharge specific capacity, the compaction density and the fast-charging performance of the hard carbon material cannot be balanced in the prior art is solved, so that the comprehensive performance of the hard carbon material is improved.

This invention discloses a graded lithium iron phosphate material and its preparation method, belonging to the field of positive electrode active materials for lithium-ion batteries. The method involves preparing two types of iron phosphate using a co-precipitation method, with at least one type being a doped iron phosphate. The two types of iron phosphate are coarsely ground and mixed in deionized water or methanol to obtain a uniform iron phosphate slurry. A lithium source, carbon source, and additives are added to the iron phosphate slurry, along with deionized water or methanol, and the mixture is finely ground and mixed to obtain a uniform mixed slurry. The mixed slurry is granulated using a spray granulation device to obtain a dry powder. Under nitrogen protection, the powder is sintered in a kiln, and the sintered material is obtained after furnace cooling. The sintered material is then crushed, graded, and sieved to obtain the graded lithium iron phosphate material. The lithium iron phosphate material prepared by this invention can be used as a positive electrode active material for automotive power lithium batteries, providing better power performance.

The application provides a secondary battery and an electronic device, the secondary battery comprising a positive electrode sheet and a negative electrode sheet, the positive electrode sheet comprising a positive electrode current collector and a positive electrode material layer, the negative electrode sheet comprising a negative electrode current collector and a negative electrode material layer, the negative electrode material layer comprising a first negative electrode material layer and a second negative electrode material layer, a half of a width difference between the first negative electrode material layer and the second negative electrode material layer being W mm, a half of a width difference between the first negative electrode material layer and the positive electrode material layer being L mm, and 0.2≤W / L≤4. The first negative electrode active material comprises a first graphite material, the second negative electrode active material comprises a second graphite material and a silicon-based material, the average particle size of the particles of the first negative electrode active material being D1 μm, the average particle size of the particles of the second negative electrode active material being D2 μm, and 1.1≤D2 / D1≤1.8. Through the above arrangement, the side reaction of the edge region of the sheet can be reduced, and the cycle performance of the secondary battery can be improved.

The application discloses a high-load dry-method electrode preparation method in the technical field of energy storage batteries, and comprises the following steps: S1, stirring and mixing of a conductive agent and a binder to obtain intermediate 1; S2, low-degree fiberization of intermediate 1 by stirring to obtain intermediate 2; S3, addition of an active material to intermediate 2 and low-speed stirring to obtain intermediate 3; S4, fiberization of intermediate 3 by stirring to obtain a granular active material mixture; S5, repeated multiple times of pressure extension and thinning of the active material mixture by using a hot-pressing device until the compaction density reaches a set value, and multiple self-supporting films with high compaction density are obtained; S6, sequential adhesion and compounding of the multiple self-supporting films to a current collector by using conductive glue to obtain a composite self-supporting film, and hot-pressing of the composite self-supporting film and the current collector to obtain a high-load dry-method electrode sheet. The thin film sheet with higher compaction density is obtained by multiple times of thinning, and the electrode sheet with high load is obtained by the lamination and compounding method.

The application provides a preparation method of a lithium iron phosphate positive electrode material modified by phosphoric acid pretreatment and ion doping. Lithium source, iron source, phosphorus source, carbon source, titanium source and vanadium source are mixed with water as a solvent and then sand milling is performed; the slurry is taken out after sand milling; the slurry is subjected to spray drying to obtain yellow material; the yellow material is subjected to primary calcination under an inert atmosphere to obtain a lithium iron phosphate precursor; the lithium iron phosphate precursor is aged in a phosphoric acid solution and then subjected to suction filtration and drying to obtain black powder; and the black powder is subjected to secondary calcination under an inert atmosphere to obtain the lithium iron phosphate positive electrode material. By dispersing the lithium iron phosphate precursor in a phosphoric acid solution with a certain concentration, defects are generated on the surface of the precursor after acidification, which is beneficial to the growth of particles after secondary calcination, improves the compaction density, and the residual phosphate groups are attached to the surface of the precursor and penetrate into the surface layer, which can promote the diffusion of lithium ions between particles and the transmission of lithium ions and electrons between particles.

The application provides a high-silica / phenolic resin composite material and a preparation method thereof, and belongs to the technical field of composite materials. The preparation method of the high-silica / phenolic resin composite material comprises the following steps: performing desolventizing treatment on high-silica fiber / phenolic resin premix to obtain high-silica fiber / phenolic resin dry mix; performing pre-pressing treatment on the high-silica fiber / phenolic resin dry mix to obtain high-silica fiber / phenolic resin pre-pressing material; and laying a silicone rubber plate on the high-silica fiber / phenolic resin pre-pressing material, and then performing mold closing treatment, pre-curing treatment and curing treatment to obtain the high-silica / phenolic resin composite material. The preparation method provided by the application can realize the preparation of large-size composite materials without using a large-tonnage press during the mold pressing process, solves the problem that a large-tonnage press needs to be used for pressing during the preparation process of the existing large-size composite materials, and the prepared composite material has good internal quality stability, a small defect area and good popularization and application value.

The invention belongs to the technical field of lithium ion battery positive electrode materials, and discloses a lithium manganese iron phosphate material with a solid-hollow composite structure and a preparation method thereof.The preparation method adopts a step-by-step reaction and co-sintering method, and comprises the steps that firstly, heterogeneous nucleation is achieved through the solubility product difference of manganese phosphate to form a hollow lithium manganese phosphate precursor; subsequently adding an iron source, a titanium source and other raw materials, and performing spray drying and inert atmosphere sintering to construct a composite structure of solid particles and hollow particles; the lithium manganese iron phosphate material with the solid-hollow composite structure has the characteristics that solid particles provide mechanical support, hollow microspheres increase ion conduction channels and a compact structure formed by a three-dimensional network, and the compaction density gt of a pole piece is realized; 2.5 g / cm < 3 > and 2C rate capacity retention rate gt; and the method has important new energy automobile and large-scale energy storage industrialization application value.

The application relates to a preparation method of a lithium battery diaphragm and belongs to the technical field of lithium battery preparation. The method is as follows: epoxy resin, a diluent, a curing agent 1 and an oleophilic emulsifier are uniformly mixed to obtain dispersion liquid 1; an electrolyte solution is constantly dropped into the dispersion liquid 1, constant-temperature high-speed stirring is carried out, and a water-in-oil emulsion is obtained; under constant temperature, deionized water, a hydrophilic emulsifier and a curing agent 2 are uniformly mixed to obtain dispersion liquid 2; the water-in-oil emulsion is added into the dispersion liquid 2, high-speed emulsification is carried out, and a water-in-oil-in-water emulsion system is obtained; the water-in-oil-in-water emulsion system is subjected to temperature rising and curing; after curing, centrifugal separation, washing and drying are carried out, and a solid nanometer adhesive is obtained; the solid nanometer adhesive is ground, then is uniformly coated in a mold and is subjected to high-temperature treatment, and the lithium battery diaphragm is obtained. The electrolyte solution is selected as the inner water phase of the water-in-oil emulsion, the internal osmotic pressure of the emulsion can be increased, fusion between the emulsions can be prevented, and the particle size is increased.

The present application relates to a kind of lithium iron phosphate material, the lithium iron phosphate material has typical olivine structure, belongs to orthorhombic space group Pnma, the preparation method of the lithium iron phosphate material, comprising the following steps: (1) lithium carbonate of battery grade, boric acid, magnesium hydroxide are mixed uniformly according to certain proportion with iron phosphate, carbon source, wherein, n1 lithium carbonate: n2 iron phosphate is 1~1.02:1, the addition amount of carbon source is 10~15% of total weight, boric acid, magnesium hydroxide as additive, the content of boric acid, magnesium hydroxide is 0~2%, obtain mixture S1;(2) S1 is placed into fine grinder and is finely ground, speed 20~50r / min;Time 0.5~1h, obtain D50 particle size 0.5~0.6 μm mixed product S2;(3) S2 is sprayed in spraying equipment, obtain product S3, in roller hearth kiln sintering, sintering temperature is 650~800 DEG C, sintering atmosphere is inert gas, sintering time is 1~8h, obtain product as S4.By adding low melting point substance boric acid and magnesium hydroxide, it is conducive to sintering reaction LiFePO4 Crystal growth.