205results 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.

The invention provides a preparation method of a lithium iron phosphate material, a lithium ion battery and electric equipment, and relates to the technical field of batteries. The method comprises the following steps: mixing raw materials of an iron source, a lithium source and a phosphorus source with a reagent serving as a reducing agent and a carbon source, and grinding to obtain precursor powder; wherein the molar ratio of the lithium source to the iron source is 1.03-1.05, and the molar ratio of the iron source to the phosphorus source is 0.965-0.99; carrying out high-temperature treatment on the precursor powder in an inert atmosphere to obtain a lithium iron phosphate base material; and crushing the lithium iron phosphate base material to obtain the lithium iron phosphate material meeting the particle size requirement. The high-capacity and high-compaction lithium iron phosphate material is obtained by accurately controlling key indexes such as the iron-phosphorus ratio, the carbon content, the graphitization degree and the particle size and combining an optimized processing technology, so that the fast charging performance of a lithium ion battery is improved, and the effect of not reducing the electric quantity while the fast charging requirement is met is achieved.

The invention relates to the technical field of lithium ion battery materials, and provides a lithium iron phosphate positive electrode material, a preparation method thereof and a lithium battery. The preparation method of the lithium iron phosphate positive electrode material comprises the following steps: performing a first coprecipitation reaction on a first iron source solution and a first phosphorus source solution in the presence of a polymer monomer to obtain an iron phosphate seed crystal; performing a second coprecipitation reaction on the second iron source solution and the second phosphorus source solution in the presence of a polymer monomer and an iron phosphate seed crystal to obtain iron phosphate dihydrate; iron phosphate dihydrate, a lithium source and a carbon source are mixed and then subjected to spray drying, the mixture is placed in a rotary kiln to be sintered, carbon-coated lithium iron phosphate with the large particle size and carbon-coated lithium iron phosphate with the small particle size are prepared at different sintering temperatures respectively, and the carbon-coated lithium iron phosphate with the different particle sizes are mixed according to the mass ratio to obtain the lithium iron phosphate positive electrode material. The lithium iron phosphate positive electrode material has relatively good spherical morphology, so that the lithium iron phosphate positive electrode material has relatively high compaction density and electrical properties after grading.

The invention discloses a ferric sodium pyrophosphate positive electrode material, a preparation method thereof and a battery, and relates to the technical field of batteries. Pre-sintering is performed; sanding and spray drying; and high-temperature sintering. Wherein the pH value of the reaction is controlled by using a Tris-HCl buffer solution in the hydrothermal reaction, so that the precursor is uniformly crystallized and has high crystallinity, and low-temperature segmented presintering is adopted later, so that the compaction density of the material can be controlled, and the related electrical properties of the material are relatively good. In the preparation process, a carbon source and a doping element are supplemented twice, so that carbon coating is uniform in the sintering process, the compaction density of the NFPP positive electrode material is further improved, the properties such as theoretical specific capacity of the positive electrode material are better through doping and carbon coating modification, and the high-compaction and high-capacity ferric sodium pyrophosphate positive electrode material is obtained.

The invention provides a preparation method of a lithium manganese iron phosphate material, and relates to the technical field of positive electrode materials. The preparation method of the lithium manganese iron phosphate material comprises the following steps: mixing a first raw material component consisting of ferromanganese oxalate, a first lithium source, a first phosphorus source, a first carbon source and a first doping agent, adding deionized water, grinding, and then carrying out spray drying to obtain a precursor A; mixing a second raw material component consisting of carbon-coated ferromanganese oxalate, a second lithium source, a second phosphorus source, a second carbon source and a second doping agent, adding deionized water, grinding, and performing spray drying to obtain a precursor B; and uniformly mixing the precursor A and the precursor B, sintering in an inert atmosphere, and crushing to obtain the lithium manganese iron phosphate material. According to the lithium manganese iron phosphate material, on the premise of ensuring high specific capacity, relatively high compaction density and relatively high rate capability are realized at the same time.

The invention provides a negative pole piece and a preparation method thereof, a sodium ion battery and electric equipment, and relates to the technical field of sodium ion batteries. The negative pole piece comprises a current collector, a first coating and a second coating, the first coating is arranged between the current collector and the second coating; the raw materials of the first coating comprise hard carbon, first soft carbon, a first conductive agent, a first dispersant and a first binder; the second coating is prepared from the following raw materials: second soft carbon, a second conductive agent, a second dispersing agent and a second binding agent. The negative pole piece has relatively high flexibility, compaction density, electronic conductivity, cycle performance and rate capability, and can also reduce the risk of sodium precipitation and the probability of powder falling.

The invention discloses a hard carbon negative electrode material for a sodium-ion battery as well as a preparation method and application of the hard carbon negative electrode material. The hard carbon negative electrode material for the sodium ion battery is a graphite microcrystal cross-linked hard carbon material, and the carbon layer spacing is 0.37 nm to 0.40 nm; the range of the Raman D / G (w) value is 1.1-1.6; and the compaction density of the 3T powder is 0.96 g / cm < 3 >-1.10 g / cm < 3 >. The hard carbon negative electrode material for the sodium ion battery has high capacity, high compaction, high magnification and high cycle performance; meanwhile, amorphous carbon is directionally etched through chemical reaction, and a second carbon source is compounded on the basis, so that the crosslinking degree between graphite microcrystals (a structural unit of hard carbon) is improved, open pores are further promoted to be converted into closed pores, sodium storage sites of the closed pores are increased, and the density and conductivity of the hard carbon material are improved; and the capacity, the compaction density, the multiplying power and the cycle performance are improved.

The invention discloses a high-compaction lithium manganese iron phosphate material as well as a preparation method and application thereof. The preparation method comprises the following steps: firstly, respectively preparing large-particle-size ferromanganese phosphate and small-particle-size ferromanganese phosphate through an oxidation-reduction reaction, then compounding the large-particle-size ferromanganese phosphate and the small-particle-size ferromanganese phosphate to serve as a precursor for synthesizing the lithium ferromanganese phosphate, and reacting the precursor with raw materials such as a lithium source to prepare the lithium ferromanganese phosphate. The two precursors with specific particle sizes are compounded, so that the small-particle-size precursor can effectively fill gaps of the large-particle-size precursor, the compaction density of the lithium manganese iron phosphate product is further improved, and meanwhile, excellent electrical properties can be realized.

The invention discloses a method for synthesizing ferric phosphate pyrophosphate and preparing a sodium ferric phosphate pyrophosphate positive electrode material. The method comprises the following steps: S1, preparing a raw material solution; s2, adding the ferric salt solution, the phosphate radical solution and the pyrophosphate radical solution into the reaction base solution, controlling the pH value, and carrying out coprecipitation reaction; s3, filtering and washing, adding water, and pulping again; s4, heating and crystallizing; s5, filtering and drying; s6, sintering to obtain ferric pyrophosphate Fe6 (PO4) 2 (P2O7) 3; s7, adding ferric pyrophosphate, a sodium source and a carbon source into water, pulping, and sanding; s8, spray drying; and S9, sintering is carried out, such that Na4Fe3 (PO4) 2 (P2O7) / C is obtained. According to the method, a precursor Fe6 (PO4) 2 (P2O7) 3 is synthesized firstly, long-range ordered mixing of Fe and P elements on the atomic scale is achieved, the morphology and particle size of the precursor are controllable, the problem of generation of inactive impure-phase NaFePO4 in the synthesis process of ferric sodium pyrophosphate can be effectively solved, the raw material utilization rate is high, and the synthesized positive electrode material is large in tap density and compaction density and excellent in electrochemical performance.

The invention discloses a high-compaction-density ferromanganese phosphate precursor and a preparation method thereof, and belongs to the technical field of lithium batteries, and the provided preparation method comprises the following steps: step 1, respectively dissolving a manganese source, an iron source and a phosphorus source in water to form solutions; 2, adding a complexing agent into the iron source solution to form a complexing iron salt solution; step 3, mixing the complexing ferric salt solution, the manganese source solution and the phosphorus source solution, adding an oxidizing agent and alkali liquor, keeping the pH value of the system to be 5.5-8, heating and stirring for reaction, and synchronously introducing oxygen for bubbling during reaction; and 4, after the reaction is finished, carrying out solid-liquid separation, and drying and roasting to obtain the ferromanganese phosphate precursor. According to the method, under the action of the complexing agent, the homogeneity of iron-manganese coprecipitation is improved, oxygen is introduced for bubbling in the reaction process, and excessive growth of crystals is inhibited while the oxidation condition is ensured, so that the ferromanganese phosphate precursor is proper in particle size and uniform in distribution, and the positive electrode material prepared from the precursor has high compaction density and excellent electrochemical performance.

The invention provides a positive electrode material as well as a preparation method and application thereof, and relates to the technical field of lithium ion batteries. The particle size distribution curve of the positive electrode material is bimodal distribution, the positive electrode material is composed of large-particle-size secondary spherical particles and small-particle-size secondary spherical particles, the large-particle-size secondary spherical particles are composed of small-particle-size primary spherical particles, the small-particle-size secondary spherical particles are composed of large-particle-size primary spherical particles, and the large-particle-size primary spherical particles are composed of small-particle-size primary spherical particles. The D50 of the large-particle-size secondary sphere particles is 8.0-12.0 [mu] m, the D50 of the small-particle-size secondary sphere particles is 2.0-4.0 [mu] m, the maximum diameter of the small-particle-size secondary sphere particles is not more than 5 [mu] m, and the minimum diameter of the large-particle-size secondary sphere particles is not less than 5 [mu] m. Compared with the prior art, the invention provides the positive electrode material matched with two secondary spherical particles with different primary spherical particle sizes, so that the compaction density and the cycling stability of the positive electrode material are improved.

The invention belongs to the technical field of lithium batteries, and provides a preparation method of a boron-doped coated lithium iron manganese phosphate positive electrode material and a lithium battery, and the method comprises the following steps: S10, performing first pretreatment based on a lithium source, an iron source, a phosphorus source, a dopant, a dispersant, a first MOF and a solvent to obtain a first precursor; s20, performing first sintering crushing on the first precursor in an inert gas atmosphere to obtain a lithium iron phosphate precursor; s30, performing second pretreatment based on the second MOF, deionized water, a carbon source, a dispersing agent and the lithium iron phosphate precursor to obtain a second precursor; and S40, grinding and drying the second precursor, and carrying out second sintering crushing in an inert gas atmosphere to obtain the lithium iron manganese phosphate positive electrode material. Wherein the first MOF is a boron-based MOF, and the second MOF is a manganese-based MOF. The lithium ion intercalation and deintercalation efficiency is improved, the specific capacity, the cycle capacity retention ratio, the compaction density and the safety of the battery are improved, and the performance of the material is improved from multiple aspects.

The invention provides a ferric sodium pyrophosphate positive electrode material as well as a preparation method and application thereof. The D50 of the sodium ferric phosphate pyrophosphate positive electrode material is 2-10 [mu] m, and the maximum particle size of the sodium ferric phosphate pyrophosphate positive electrode material is less than 25 [mu] m; the internal porosity of the ferric sodium pyrophosphate positive electrode material is less than 14%, and the compaction density is greater than 2.17 g / cm < 3 >. According to the invention, the compaction density of the ferric sodium pyrophosphate positive electrode material can be improved.

The invention provides a battery, a battery pack and a power utilization device, and belongs to the technical field of batteries, the battery comprises a positive plate, a negative plate and an electrolyte; the battery meets the following conditions: # imgabs0 #, V represents the viscosity of the electrolyte, and the unit is mPa.s; pD represents the compaction density of the positive plate, and the unit is g / cm < 3 >; c represents the liquid injection coefficient of the electrolyte, and the unit is g / Ah. According to the battery provided by the embodiment of the invention, by meeting the formula, the good wettability of the electrolyte on the positive plate can be ensured under the condition that the compaction density and the surface density of the positive plate in the battery are relatively high, so that the negative influence caused by the improvement of the compaction density and the surface density is reduced while the battery has high energy density, and the service life of the battery is prolonged. The charge transfer efficiency is improved, the battery cycle performance is optimized, the battery power density is improved, and the comprehensive performance of the battery is improved.

The invention discloses a lithium iron phosphate positive electrode material, a preparation method thereof and a lithium ion battery, and relates to the technical field of batteries. The lithium iron phosphate positive electrode material comprises primary particles and secondary particles, the secondary particles are formed by aggregating the primary particles, the lithium iron phosphate positive electrode material meets # imgabs0 # = 5-40 and rho% = 50%-90%, FSSS refers to the Fisher particle size of the lithium iron phosphate positive electrode material, DBET refers to the specific surface area particle size of the lithium iron phosphate positive electrode material, and rho% refers to the relative density of the secondary particles. The invention provides the lithium iron phosphate positive electrode material which simultaneously meets the conditions that # imgabs1 # is equal to 5-40 and rho% is equal to 50%-90%, the lithium iron phosphate positive electrode material has good dispersity, low agglomeration degree and high compaction density, and a positive plate prepared from the lithium iron phosphate positive electrode material has the characteristics of uniform surface density and high peel strength, so that a battery prepared from the lithium iron phosphate positive electrode material has relatively high specific capacity and cycling stability.

The invention discloses a method for reducing pores formed among particles during sintering of composite ferric sodium pyrophosphate, which comprises the following steps: step 1, preparation of precursor slurry: mixing, stirring and grinding an iron source, a phosphorus source, a sodium source, a carbon source and deionized water to obtain the precursor slurry; wherein the stoichiometric ratio of the iron source to the phosphorus source to the sodium source is 3: 4: 4, and the chemical formula of the synthesized composite ferric sodium pyrophosphate is Na4Fe3 (PO4) 2P2O7; 2, carrying out spray drying on the precursor slurry to obtain a dried precursor; and step 3, loading the dried precursor in a graphite sagger, and then feeding the dried precursor into a roller kiln for sintering to obtain the composite ferric sodium pyrophosphate material. According to the invention, the solid content of the slurry is reduced to realize that the spray-dried composite phosphoric acid ferric pyrophosphate precursor forms thin-wall secondary spherical particles, and then through a unique sintering process curve, volatile components of the precursor are smoothly discharged in the sintering process, so that the composite phosphoric acid ferric pyrophosphate product without pores among particles is obtained.

The invention discloses a precursor for a polyanionic sodium ion battery positive electrode material and a preparation method of the precursor. The chemical general formula of the precursor is NaxMyHzOa (POb) c.mH2O, wherein M is a transition metal element Fe and / or Mn; the relationship among x, y, z, a, b and c is x + 3y + z-2a + 5c-2b * c = 0, and the value range of m is greater than or equal to 0. The precursor for the polyanionic sodium ion battery positive electrode material and the preparation method thereof have the characteristics of high phase purity, high compaction density, excellent electrochemical performance, low cost and wide system applicability.

The invention provides a mixed positive electrode material, positive electrode slurry, a preparation method of the positive electrode slurry, a positive electrode plate and application. The mixed positive electrode material comprises the following components in parts by weight: 95-98 parts of an active substance, 1-5 parts of a conductive agent, 1-5 parts of a binder and 0-0.5 part of a dispersing agent, the active substance comprises lithium manganese iron phosphate and lithium manganate, and the weight ratio of the lithium manganese iron phosphate to the lithium manganate is (7-8): (3-2). According to the mixed positive electrode material, the minimum energy density can be increased to 190 wh / kg or above and the rate capability can be greatly improved through the ratio of the lithium manganese iron phosphate to the lithium manganate being (7-8): (3-2); meanwhile, the lithium manganese iron phosphate is large in specific surface area and small in compaction density, and the lithium manganate is small in specific surface area and large in compaction density, so that the use amount of a dispersing agent in a homogenizing section is reduced, the surface density fluctuation of a coating section is reduced, and the compaction density is increased to 2.6 kg / m < 3 > or above.

The invention provides a method for repairing and regenerating waste lithium iron phosphate, and belongs to the technical field of recycling of lithium ion battery materials. The preparation method of the regenerated lithium iron phosphate active material comprises the following steps: obtaining waste lithium iron phosphate powder from a positive plate of a waste lithium iron phosphate battery, mixing the waste lithium iron phosphate powder with a lithium source, a ferrous reducing agent and a carbon source according to a specific ratio, and carrying out two-stage calcination in an atmosphere containing a hydrogen-nitrogen mixed gas to obtain the regenerated lithium iron phosphate active material. The regenerated lithium iron phosphate active material can be directly obtained. The method has the characteristics of short process, simplicity in operation and easiness in industrial popularization, waste materials in the process are free of acid and alkali waste liquid, high-pollution gas and the like, and the method is environment-friendly; meanwhile, the regenerated lithium iron phosphate material is high in compaction density and good in machinability, and the electrochemical performance of the formed battery is still excellent.

The invention relates to the technical field of lithium ion battery negative electrode materials, in particular to a graphite negative electrode material and a preparation method thereof, a negative electrode plate and a lithium ion battery. The graphite negative electrode material comprises composite particles, the composite particles comprise graphite particles and polymer films coating the surfaces of the graphite particles, and the materials of the polymer films comprise polyolefin and / or polyurethane; the weight loss ratio of a TG curve obtained by carrying out a thermal weight loss test on the graphite negative electrode material in an air atmosphere at 200-600 DEG C is 1%-5%. The surfaces of the graphite particles are coated with a small amount of polyolefin and / or polyurethane, so that the specific surface area can be remarkably reduced, and the compaction density can be improved.

The invention provides a high-voltage-resistant lithium ion negative electrode plate and a lithium ion battery, and the negative electrode plate adopts the particle size grading of graphite with a specific particle size and a silicon material with a specific particle size, and optimizes a low-expansion and high-compaction negative electrode material and a formula. Graphite with a specific particle size and a spheroidal (spherical) silicon negative electrode coated with a conductive agent are subjected to particle size grading, so that the dispersion uniformity can be improved, the compaction density of a pole piece is improved, the pressure resistance of the pole piece is improved, and meanwhile, the expansion of the silicon negative electrode is reduced; the overall dynamic performance and stability of the lithium ion battery prepared by using the negative pole piece can be greatly improved.

The invention provides a high-energy-density lithium iron phosphate positive electrode slurry and a preparation method and application thereof, and the method comprises the following steps: step doping, mixing and grinding a phosphorus source, a lithium source and an iron source, re-mixing the materials after spray drying and calcining, adding a coating agent, and sanding and calcining to form lithium iron phosphate powder doped with metal ions; adding the lithium iron phosphate powder doped with metal ions, a dispersing agent and a conductive binder into a stirring tank according to a ratio, stirring, dispersing and carrying out dry mixing; adding an organic solvent, stirring and dispersing, stopping the machine, scraping the paddle and the wall, and stirring and dispersing again; vacuumizing, reversing for defoaming, closing the dispersion speed, and stirring to obtain the dispersing agent. The addition amount of the lithium iron phosphate doped with the metal ions is 97%-99%; the addition amount of the conductive adhesive is 0.5%-2.5%; according to the invention, the non-fluorine binder is compounded with the conductive active component to solve the problems of peel strength and pole piece flexibility, and the peel strength of the material is greater than 150N / m under the condition that the addition amount of the binder is less than 1%.

The invention discloses a high-conductivity sodium ion battery positive electrode material / organic conductive polymer composite material and a preparation method thereof, and the preparation method comprises the following steps: S1, preparation of a chain product: adding water into an organic conductive polymer monomer for dissolving, adjusting the pH value of the solution to be acidic, adding an oxidizing agent, and stirring to obtain the chain product; inducing an organic conductive polymer monomer to generate a polymerization reaction to form a chain product; s2, preparation of precursor slurry: adding a sodium source, an iron source and a sulfur source into the solution for forming the chain product, and fully dissolving to form uniform precursor slurry; s3, preparation of precursor powder: drying the precursor slurry to realize solid-liquid separation so as to obtain dried precursor powder; and S4, high-temperature sintering: calcining the precursor powder in a protective atmosphere, and naturally cooling to obtain the Na < 2 + x > Fe < 2-x > (SO4) 3 / organic conductive polymer composite positive electrode material. The preparation method has the characteristics of high electronic conductivity, low specific surface area, high compaction density and excellent electrochemical performance.

The invention relates to the technical field of batteries, and discloses a positive plate and a lithium ion secondary battery. The positive plate comprises a first positive active material layer, the first positive active material layer comprises a first positive active material, a conductive agent and a binder, the first positive active material comprises a ternary material and a lithium manganate material, and the conductive agent comprises a carbon nanotube. By regulating and controlling the particle size A of the first positive electrode active material and the length L of the carbon nanotube, A is greater than or equal to 2.14 and less than or equal to 12.5, A is equal to Dv99 / Dv50PAM, and L is greater than or equal to 5 microns and greater than or equal to 30 microns, so that the energy density, the thermal stability, the high-temperature cycle performance and the rate capability of the battery can be improved at the same time.

The invention discloses modified ferromanganese ammonium phosphate, modified ferromanganese pyrophosphate and a preparation method and application of the modified ferromanganese ammonium phosphate and the modified ferromanganese pyrophosphate, and belongs to the technical field of battery materials. Adding an oxidizing agent and regulating the pH to form ammonium ferric phosphate, and carrying out ion exchange reaction on the ammonium ferric phosphate, manganese salt and doped metal salt to exchange iron elements in the ammonium ferric phosphate to form metal doped ammonium manganese ferric phosphate; meanwhile, the exchanged iron ions continuously react with phosphate radicals generated by converting manganese ions, doped metal ions and ferrous dihydrogen phosphate into iron phosphate in the system to form metal-doped manganese iron ammonium phosphate, so that manganese, iron and doped metal atoms can be uniformly distributed in a precursor crystal lattice at an atomic level; the generation of a non-solid solution impure phase and a solid solution phase with a non-target manganese-iron ratio and the introduction of anion impurities are effectively avoided, so that the ratio of metal to phosphorus in the metal-doped ammonium manganese iron phosphate obtained by the reaction is less than 1, and the electrochemical performance of the modified lithium manganese iron phosphate is favorably improved when the metal-doped ammonium manganese iron phosphate is applied to the positive electrode material.

The invention provides a high-compaction phosphate positive electrode material, a preparation method thereof and a lithium ion battery positive electrode, the phosphate positive electrode material comprises a phosphate core and a B-C composite coating layer coating the surface of the phosphate core, and the B-C composite coating layer comprises BC3, borate and amorphous carbon; the general formula of the borate is MxByOz, M comprises Li and / or Fe, x is 1-3, y is 1-4, and z is 3-7; the preparation method comprises the following steps: mixing a phosphate precursor material, a boron source and a carbon source, and sequentially carrying out ball milling and sintering to obtain the high-compaction phosphate positive electrode material. According to the invention, the boron source can be melted at a high temperature and is used as a fluxing agent to reduce the surface tension of particles, improve the morphology of the particles and improve the compaction density of the phosphate positive electrode material.

The invention belongs to the technical field of batteries, and particularly discloses a positive electrode material and a preparation method thereof, a lithium ion battery and a power utilization device, the positive electrode material comprises lithium manganese iron phosphate, the unit cell volume of the lithium manganese iron phosphate is # imgabs0 #, the positive electrode material has high compaction density, electronic conductivity and ionic conductivity, and the lithium ion battery can be used as a lithium ion battery. By adopting the positive electrode material, the energy density and the cycling stability of the battery containing the positive electrode material can be improved.

The invention provides a production device and a production method of a core-shell precursor with normal particle size distribution, the production device comprises a homogeneous reactor, a stirring reactor and a thickener which are sequentially connected through a pipeline, and the thickener is connected back to the stirring reactor through a pipeline to form a material circulation loop; the production device adopts a continuous method to produce the core-shell precursor with normal particle size distribution. According to the method, a homogeneous reactor and a stirring reactor are adopted to synchronously carry out coprecipitation reaction, and a thickener is adopted to realize continuous reaction and particle size control, so that a core-shell precursor with normal particle size distribution is obtained. The problem of heat instability of a high-nickel positive electrode material in the prior art is solved, meanwhile, the production efficiency and quality of the core-shell precursor are improved, the performance and safety of the battery are finally improved, and large-scale popularization and application are facilitated.

The invention discloses high-pressure density lithium iron phosphate and a preparation method thereof, and belongs to the field of lithium ion battery positive electrode active materials. The preparation method comprises the following steps: adding high-activity iron phosphate and low-activity iron phosphate into a solvent, stirring, adding lithium carbonate, stirring, adding a carbon source and an additive, and uniformly stirring to obtain slurry; grinding the slurry by using a nanometer grinder, and monitoring the granularity of the ground slurry by using a nanometer granularity analyzer; pumping the ground slurry into a spray dryer, and drying and granulating to obtain a powder material; putting the powder material into a graphite crucible, putting the graphite crucible into a kiln, and sintering under the protection of nitrogen; and crushing and sieving the sintered material to obtain the high-pressure density lithium iron phosphate powder. The high-pressure density lithium iron phosphate material prepared by the invention can provide higher energy density per unit volume, and can be used as a positive electrode active material of a vehicle power type or base station energy storage type lithium battery.

The invention relates to the technical field of lithium battery additives, in particular to a positive electrode softener, lithium ion battery positive electrode slurry and a preparation method, the positive electrode softener is a binary, ternary or multipolymer of olefin containing carbon-carbon double bonds and ester containing carbon-carbon double bonds, is an amorphous material with a low glass transition temperature, and can be applied to lithium ion batteries. Good affinity with a conductive agent material is realized. In the optimal addition amount range, the positive softener can reduce the viscosity of positive slurry, improve the dispersion uniformity of a conductive agent, improve the compaction density of a positive electrode and the flexibility of a pole piece, and solve the problems of low compaction degree and high brittleness of the pole piece of an existing lithium battery; therefore, the lithium ion battery adopting the positive electrode slurry has excellent processing performance and electrical performance.