2113 results about "Iron phosphate" patented technology

The invention belongs to the technical field of iron phosphate preparation, and discloses an energy-saving control system for iron phosphate preparation based on an energy consumption scheduling model. The system is composed of a data acquisition module, an energy consumption sensing module, a preparation process modeling module, an energy consumption prediction module, an energy-saving scheduling module, an intelligent execution module, a feedback correction module, a man-machine interaction module and a remote operation and maintenance module. The energy consumption sensing module intelligently senses an energy consumption state, the preparation process modeling and energy consumption prediction module accurately predicts energy consumption, the energy-saving scheduling module generates an optimal scheduling strategy, the intelligent execution module accurately executes an instruction, and the feedback correction module realizes closed-loop adaptive regulation and control; all the modules cooperatively operate, process parameters are adjusted in real time according to actual working conditions of iron phosphate preparation, energy consumption in the preparation process is remarkably reduced, the energy utilization rate is increased, and energy-saving optimization of iron phosphate preparation is achieved.

The invention discloses a modified carbon-coated sodium manganese ferric phosphate pyrophosphate / sodium ferric phosphate pyrophosphate positive electrode material as well as a preparation method and application thereof, and relates to the technical field of new energy materials. The preparation method comprises the following steps: preparing MnFe-MOF from a manganese source, a first iron source and a first organic ligand under a hydrothermal reaction; a second iron source, the MnFe-MOF and a second organic ligand are subjected to a hydrothermal reaction, and MnFe-MOF / Fe-MOF is obtained; uniformly mixing with a sodium source and a phosphorus source, and sintering to obtain a positive electrode material; and carrying out high-temperature gas-phase etching treatment to obtain the fluorine-doped carbon-coated modified sodium manganese ferric phosphate pyrophosphate / sodium ferric phosphate pyrophosphate positive electrode material. The material disclosed by the invention has a coating modified structure, so that an interface side reaction caused by direct contact between sodium ferromanganese phosphate and an electrolyte can be effectively avoided, a manganese dissolution phenomenon is reduced, and the structural stability of the material is improved; and meanwhile, the material has high conductivity, excellent structural stability, excellent long cycle life and excellent rate capability.

The invention relates to the technical field of battery positive electrode materials, and provides a lithium iron phosphate positive electrode material and a preparation method thereof. The lithium iron phosphate positive electrode material has the characteristic of high energy density, the proportion of iron phosphide impurities in the total mass of the lithium iron phosphate positive electrode material is 0.001-0.008 PPM, the compaction density under the pressure of 3T is 2.68-2.8 g / cm < 3 >, the powder resistivity is 8-15 omega.cm, the 0.1 C discharge capacity is 161-163 mAh / g, the 0.1 C charge-discharge efficiency is 98.5-100%, and the 1C discharge capacity is 145-148 mAh / g. The preparation process is simple and safe, low in cost and high in stability. The content of iron phosphide impurities in a final lithium iron phosphate product can be regulated and controlled by regulating and controlling the phosphorus-iron ratio of the iron phosphate precursor and the ratio of the carbon source to the iron phosphate precursor in two-time burdening and controlling the sintering temperature in cooperation with secondary sintering, and the high-energy-density lithium iron phosphate positive electrode material is obtained.

The invention provides a method for preparing a high-performance lithium manganese iron phosphate positive electrode material based on a manganese iron phosphate precursor, and relates to the technical field of batteries. A method for preparing a high-performance lithium manganese iron phosphate positive electrode material based on a manganese iron phosphate precursor comprises the following steps: S1, mixing a phosphorus source, an iron source and a manganese source in a water medium, adding a surfactant, and carrying out ball milling, drying and sintering to obtain the manganese iron phosphate precursor; and S2, mixing the manganese iron phosphate precursor, a lithium source, a carbon source, a doping agent, an auxiliary agent and deionized water, and carrying out ball milling, drying and sintering to obtain the lithium manganese iron phosphate positive electrode material. The method can improve the surface / interface stability while improving the surface conductivity of the material, thereby prolonging the cycle life of the battery and improving the charge-discharge capacity of the battery.

This invention discloses a method for leaching lithium iron phosphate mixed powder with iron salts and recovering all components, belonging to the field of battery recycling. The invention uses an iron salt solution to leach the mixed powder, obtaining a lithium-containing leachate and leaching residue. Ferrous ions in the leachate are regenerated into ferric iron through acidification and oxidation, and recycled for leaching the next batch of mixed powder. After reaching a preset number of cycles, the leachate is used for re-leaching multiple batches of leaching residue to improve the lithium leaching rate. Ultimately, a enriched solution containing Li, Fe, Cu, and Al and graphite-containing iron phosphate residue are obtained. Copper is recovered from the enriched solution through iron powder replacement, and a high-purity lithium chloride solution is obtained through extraction and separation, while ferric chloride (recycled) and aluminum chloride crystals are also recovered. The leaching residue is treated with hydrochloric acid to obtain regenerated graphite, and the pH is adjusted with alkali to obtain high-purity iron phosphate. This method achieves full component recovery under mild conditions, reducing separation steps and chemical consumption through a "leaching-regeneration-leaching" cycle mechanism, thus achieving both environmental and economic benefits.

The invention belongs to the technical field of chemical process intelligent control, and discloses an iron phosphate synthesis parameter self-adaptive control system based on an intelligent algorithm. The system is composed of a target quality sensing module, a reaction data acquisition and preprocessing module, a sensitive section identification module, a process boundary modeling module, a multi-strategy control model library module, a strategy evaluation and structure evolution module and a control execution and feedback module. According to the method, a multi-module cooperation mechanism including target scoring modeling, dynamic sensitive segment identification and reaction boundary modeling is constructed, so that whole-process online identification and segmented precise control of the crystal form, the particle size and the crystallinity of a product in the iron phosphate synthesis process are realized; compared with a traditional control system depending on experience setting and univariate feedback, the system has the advantages of being higher in state sensing depth, more accurate in crystal form conversion process recognition, finer in reaction stage regulation and control and the like, and the problems of crystal form deviation, particle size drift and inter-batch quality fluctuation are effectively solved.

The invention relates to a preparation method of a nickel ion doped modified ferric sodium pyrophosphate positive electrode material, and belongs to the technical field of sodium ion battery positive electrode materials. The nickel ion doped modified ferric sodium pyrophosphate positive electrode material is prepared by adopting an integrated process system of liquid phase uniform mixing, spray granulation and precise segmented calcination. According to the process system, atomic-scale uniform doping of nickel ions and a specific microstructure of a precursor are realized through spray drying, and a plurality of inherent key technical problems of low electronic conductivity, low ion diffusion rate, impurity phase generation and the like of an NFPP material are solved together through a synergistic effect with a subsequent calcining process; furthermore, the discharge capacity of the ferric sodium phosphate pyrophosphate composite material at high rate is improved, so that the battery has relatively high cycling stability.

The invention discloses a production method of ferrous dihydrogen phosphate, which comprises the following steps of: changing an iron source of iron-process iron phosphate from traditional iron blocks or iron powder into oxide scale, compounding phosphoric acid and sulfuric acid into mixed acid, and controlling the granularity of the oxide scale and the components and acidity of the mixed acid to solve the problems of dissolution and passivation of the oxide scale. According to the method, iron oxide scale can be better dissolved, the residual problem of ferric ions is solved by reducing excessive iron blocks or iron powder, undissolved impurities such as carbon, silicon and iron are removed by filtering, and finally, the stability problem of a reaction system is solved by adjusting the pH value of the system through industrial phosphoric acid and pure water, so that a ferrous dihydrogen phosphate solution required for producing iron phosphate is obtained. The production cost of an iron source required by iron phosphate is greatly reduced, other impurities are not contained, and mixed acid-containing filtrate and washing water generated in the production process can be recycled through an evaporation device.

The preparation method comprises the following steps: S1, preparing a phosphoric acid solution, a hydrogen peroxide solution, a Ti salt, a phosphor salt solution and a ferrite solution; s2, Ti salt and the ferrite solution are mixed, and a titanium iron salt solution is obtained; mixing the phosphoric acid solution and the phosphorus salt solution to obtain a phosphorus source solution; s3, adding the titanium iron salt solution into a reaction kettle, and adding the hydrogen peroxide solution; s4, adding the phosphorus salt solution into the reaction kettle to obtain yellow slurry; s5, after the color of the slurry is heated to be white, white slurry is obtained; s6, carrying out solid-liquid separation on the white slurry to obtain an iron phosphate dihydrate filter cake; and S7, drying and calcining the iron phosphate dihydrate filter cake to obtain the Ti-doped battery-grade anhydrous iron phosphate. The titanium-doped iron phosphate is firstly prepared by a one-step method, the pH value of the reaction system is controlled by controlling the molar ratio of the iron element to all phosphorus elements in total phosphorus, ammonium phosphate and phosphoric acid in the reaction system, and the retention of the Ti element in the finished product and the regulation and control of the iron-phosphorus ratio in a specified range are ensured.

The invention discloses a reaction kettle device for synthesis of an iron phosphate material, and particularly relates to the technical field of synthesis of battery materials, and the device comprises a kettle body, a driving motor, a transmission disc and a turbo-type paddle. A sealing cover is arranged at the top of the kettle body, a driving motor is connected with a rotating shaft, an anchor blade is arranged below the rotating shaft, and the bottom realizes turbine blade lifting and sleeve guide limiting through transmission of a piston cavity and compressed gas; and a ratchet wheel on the outer wall of the rotating shaft is meshed with a pawl in the transmission disc in a one-way mode, and intermittent wall scraping is achieved. According to the device, dead angles are broken through synergistic stirring of the double blades, the mixing uniformity and the reaction rate are improved, materials adhering to the wall are efficiently removed through intermittent wall scraping, the stable reaction environment is guaranteed through multiple sealing, the structure is flexible to adjust, maintenance is convenient and fast, efficient and high-quality synthesis of the iron phosphate material can be achieved, and the device is suitable for industrial large-scale production.

The invention relates to the technical field of electrode materials, and discloses a preparation method of a lithium iron manganese phosphate material and a lithium ion battery. The lithium iron manganese phosphate material is prepared by the following steps: performing in-situ growth in a cavity of polyethylene glycol-sucrose hybrid aerogel with a three-dimensional porous network structure to form a manganese iron phosphate precursor; the hybrid aerogel can control excessive agglomeration and disordered growth of ferromanganese phosphate precursor particles and avoid particle agglomeration, so that the finally formed lithium ferromanganese phosphate material particles are finer and more uniformly distributed, and an amorphous carbon-aluminum layer is formed during later calcination, so that the performance of the material is improved. The surface of lithium manganese iron phosphate particles is tightly coated with the composite material, electron transmission can be accelerated, particle pulverization can be reduced, meanwhile, corrosion of corrosive components in electrolyte can be inhibited, interface side reactions such as transition metal ion dissolution can be reduced, and finally the conductivity and cycling stability of the lithium ion battery are remarkably improved.

The invention discloses a lithium iron manganese phosphate positive electrode material and a preparation method thereof, a positive electrode plate and a secondary battery, and belongs to the technical field of lithium iron manganese phosphate batteries, the lithium iron manganese phosphate positive electrode material comprises a lithium iron manganese phosphate positive electrode active material and a solid electrolyte interface film located on the surface of the lithium iron manganese phosphate positive electrode active material, the solid electrolyte interface film contains C, N, F and O elements, and the ratio of the relative content of the C element to the relative content of the N element in the solid electrolyte interface film is (0.5-2): 1. According to the solid electrolyte interface film, the dissolution of manganese ions and the decomposition side reaction of the electrolyte at high voltage / high temperature are remarkably inhibited, the generation of gas is fundamentally reduced, the battery is free from flatulence phenomenon after being circulated at high temperature, and the safety and the reliability of the battery are greatly improved.

The invention belongs to the technical field of batteries, and discloses a carbon-coated modified lithium manganese iron phosphate positive electrode material and a preparation method and application thereof, and the carbon-coated modified lithium manganese iron phosphate positive electrode material comprises carbon-coated modified lithium manganese iron phosphate positive electrode material particles, the carbon-coated modified lithium manganese iron phosphate positive electrode material particle comprises a lithium manganese iron phosphate core, a first carbon coating layer and a second carbon coating layer, wherein the first carbon coating layer is positioned between the lithium manganese iron phosphate and the second carbon coating layer; the graphitization degree of the first carbon coating layer is greater than that of the second carbon coating layer. The carbon-coated modified lithium manganese iron phosphate positive electrode material has relatively high conductivity, compaction density and the like, and a battery using the carbon-coated modified lithium manganese iron phosphate positive electrode material has relatively high charge-discharge rate, excellent energy density, excellent capacity and the like.

The invention provides a preparation method of grain size grading iron phosphate and high compaction type lithium iron phosphate. Removing impurities from the titanium dioxide byproduct ferrous sulfate, and filtering to obtain a purified ferrous sulfate base solution; the method comprises the following steps: reacting phosphoric acid with ammonia water to prepare ammonium phosphate solutions with different reaction pH values and phosphorus molar concentrations, respectively mixing the ammonium phosphate solutions with a certain amount of hydrogen peroxide, and sequentially adding an iron source, a first phosphorus salt solution, a second phosphorus salt solution and a third phosphorus salt solution into a tubular reactor for reaction to obtain iron phosphate slurry; and sequentially converting, filtering, washing, drying and calcining the completely reacted slurry to finally prepare the anhydrous iron phosphate. According to the invention, a mode of controlling solution nucleation and growth is adopted, nucleation and growth rates are controlled by preparing phosphorus salt solutions with different concentrations, size grading of precursor particles is directly realized in a synthesis reaction section, and slurry grading uniformity is further realized through aging crystal transformation. Lithium iron phosphate prepared from the iron phosphate precursor has high compaction density.

The invention provides a moniliella malayi and a fungicide and application thereof, and relates to the field of microorganisms. The acer rubrum is specifically acer rubrum RA, and the preservation number of the acer rubrum RA is CGMCC (China General Microbiological Culture Collection Center) No.35889. The acer rubrum RA can be used for preparing the acer rubrum. The strain has the capability of decomposing inorganic phosphorus, is wide in phosphorus-dissolving range, can decompose tricalcium phosphate, iron phosphate and aluminum phosphate, and particularly still has very strong capability of decomposing inorganic phosphorus under a low-temperature condition; the strain has the capability of producing siderophore and IAA at low temperature; the strain has an inhibition effect on various pathogenic bacteria causing field crop diseases, and can inhibit diseases such as corn root rot, sorghum leaf spot or wheat root rot; the strain can be colonized in a soil environment of 5-40 DEG C, a microbial inoculum prepared from the strain can promote crop growth, the crop yield is remarkably improved, and high yield can be achieved even if the usage amount of phosphate fertilizer is reduced.

The present application relates to the technical field of battery materials, and provides iron phosphate having low sulfur content and a high iron-phosphorus ratio, a preparation method therefor, and a use thereof. The preparation method for the iron phosphate having low sulfur content and a high iron-phosphorus ratio comprises: providing amorphous iron phosphate; adding water and phosphoric acid into the amorphous iron phosphate for slurrying treatment, and then heating and aging to obtain an aged slurry; carrying out slurry washing and filter pressing on the aged slurry to obtain a first filter cake; adding water and a first pH regulator into the first filter cake for slurry washing to obtain a first slurry having a pH value range of 3.0-5.0, and carrying out filter pressing on the first slurry to obtain a second filter cake; and rinsing, drying and calcining the second filter cake to obtain iron phosphate having low sulfur content and a high iron-phosphorus ratio. The present application facilitates preparation of iron phosphate having low sulfur content, a high iron-phosphorus ratio, and a large specific surface area. The iron phosphate can be used for preparing lithium iron phosphate having good electrochemical performance, and the lithium iron phosphate can be further used for preparing a positive electrode sheet and a secondary battery having good electrochemical performance.

The invention relates to the technical field of lithium ion batteries, in particular to a preparation method of an interface-modified high-rate lithium iron phosphate positive electrode material, which is used for solving the problems of low interface impedance, low rate capability and low energy density of the existing lithium iron phosphate. According to the preparation method, zirconium-niobium co-doped iron phosphate is used as a precursor of the lithium iron phosphate positive electrode material, a lithium ion diffusion channel is widened, the lithium ion diffusion coefficient is improved, meanwhile, an olivine structure framework is provided, a wider tunnel space is provided for lithium ion migration, zirconium-niobium provides additional electrons, and the electron conductivity is improved through cooperation of the zirconium-niobium co-doped iron phosphate and the olivine structure framework; li2ZrCl6-LiCl interface modification can isolate sulfide electrolyte from being in direct contact with a positive electrode material, and interface side reaction is inhibited; carbon nanotube coating can enhance the conductivity, reduce erosion, improve the diffusion coefficient of Li < + > and the stability of the material structure, and improve the charge-discharge rate.

The invention discloses a lithium manganese iron phosphate material prepared by taking lithium iron phosphate as a template agent as well as a preparation method and application of the lithium manganese iron phosphate material. Specifically, lithium iron phosphate is taken as a template agent, other iron sources, manganese sources, lithium sources, phosphorus sources and carbon sources are added, high-energy ball milling mixing is carried out in water or an organic solvent, rheological phase reaction is carried out, and the surface of the lithium iron phosphate is uniformly coated with the raw materials. And then drying, pre-calcining, secondary carbon coating and high-temperature calcining are carried out, and bulk phase diffusion and epitaxial growth of the raw materials are synchronously carried out on the surface of the lithium iron phosphate by utilizing a solid phase diffusion-epitaxial growth coupling mechanism, so that the lithium iron manganese phosphate material is finally obtained. The lithium iron manganese phosphate prepared by taking lithium iron phosphate as a template agent and matching with other iron sources has the characteristic of manganese element concentration gradient distribution, and meanwhile, nanoscale particle refinement is realized. The secondary battery prepared by taking the lithium manganese iron phosphate as the positive electrode material has excellent electrochemical performance and cycling stability.

The application provides a lithium ion battery and an electric device, the lithium ion battery comprising a positive electrode sheet and an electrolyte, an active substance in the positive electrode sheet comprising a phosphate lithium positive electrode material and a lithium nickel cobalt manganese oxide, the electrolyte comprising a positive electrode film former, a negative electrode film former and a lithium salt, the lithium salt comprising lithium hexafluorophosphate and a lithium bisfluorosulfonylimide salt, the lithium ion battery satisfying the following formula: wherein NL is a mass ratio of the lithium nickel cobalt manganese oxide and the phosphate lithium positive electrode material, S alt is a value of a molar concentration of the lithium hexafluorophosphate and the lithium bisfluorosulfonylimide salt in the electrolyte in mol / L, and A dd is a mass ratio of the positive electrode film former and the negative electrode film former. The application can adjust the ratio of the positive electrode film former and the negative electrode film former and the ratio of the high-heat-resistance lithium salt according to the mixing ratio of the ternary material doped in the lithium manganese iron phosphate or the lithium iron phosphate, so that the cycle performance of the battery is improved.

The application provides a kind of iron phosphate material, its preparation method, positive electrode material, positive electrode sheet and secondary battery.The titanium element is doped in the iron phosphate material, at least part of the surface of the primary particle of the iron phosphate material is in laminated structure, in the multiple sheet layers of laminated structure, any two adjacent sheet layers are located on the side of each other respectively.The laminated structure forms a short-range ordered morphology, avoids the situation that sheet layer horizontal and vertical staggered causes space waste, can make the specific surface area and contact area of primary particle are more significantly improved.Moreover, the titanium element is also doped in the iron phosphate material, titanium element makes the iron phosphate material produce defects in the process of crystallization, hinders the growth of iron phosphate in a particular direction, is beneficial to the formation of laminated structure on the surface of iron phosphate particle.

The invention relates to the technical field of inorganic compound preparation, and particularly discloses a method for preparing high-purity iron phosphate through low-temperature acidolysis of phosphated residues, which comprises the following steps: washing, drying and crushing the phosphated residues to obtain phosphated residue powder; carrying out low-temperature acidolysis reaction on the phosphated residue powder and inorganic acid in an aqueous medium at 60-90 DEG C to obtain an acidolysis solution; adding an oxidizing agent into the acidolysis solution, adjusting the pH value of the system to 2.5-4.5 at 65-85 DEG C, carrying out oxidation impurity removal, and filtering to obtain an iron-containing phosphate solution; and selectively supplementing an iron source according to the molar ratio of iron to phosphorus in the solution, adjusting the pH value to 1.0-3.0, and carrying out precipitation reaction at 65-75 DEG C to generate iron phosphate. According to the method, low-energy-consumption resource utilization of the phosphated residues is achieved by combining low-temperature acidolysis with oxidation impurity removal and component regulation and control, the product purity meets the battery-grade requirement, and the method is suitable for preparing the lithium battery positive electrode material precursor.

The invention relates to the technical field of iron phosphate preparation, in particular to a preparation method of low-impurity iron phosphate with a high iron-phosphorus ratio, which at least comprises the following steps: preparing an iron source solution and a phosphorus source solution; mixing an oxidizing agent and a phosphorus source solution as a phosphorus source mixed solution; adding the phosphorus source mixed solution into the iron source solution, and controlling the molar ratio of iron to phosphorus to be 1: (1.1-1.3) to prepare slurry; dividing the slurry into two parts, respectively adding an impurity removal agent, and then carrying out segmented aging at 90 DEG C to prepare crystallized slurry; and filtering, washing, drying and calcining the crystallized slurry to obtain a target product iron phosphate finished product. The impurity removal agent is selected from one or more of ferrous sulfate, ferrous chloride, ferrous nitrate and ferrous oxalate. Seed crystals are formed through segmented aging crystal transformation to promote crystal growth, and autonomous grain size distribution is achieved; an impurity removing agent is added in the aging stage, impurities are reduced by using the same ion effect, the iron-phosphorus ratio is increased, and the compaction density and the electrical property of the prepared lithium iron phosphate are remarkably improved.

The invention relates to the technical field of lithium ion batteries, and discloses a positive electrode material and a preparation method thereof, and a lithium ion battery, the preparation method comprises the following steps: (1) mixing a phosphorus source, a manganese source and water, carrying out primary grinding, and then mixing with an oxidizing agent or a reducing agent for reaction; (2) mixing the product obtained in the step (1) with an iron phosphate solution, controlling the temperature of a mixed system to 70-100 DEG C, washing, drying for the first time and calcining for the first time to obtain an iron phosphate coated manganese iron phosphate precursor; and (3) mixing the iron phosphate coated ferromanganese phosphate precursor obtained in the step (2) with a lithium source, a carbon source and a doping element M source, and then carrying out secondary grinding, secondary drying and secondary calcination. By adopting the preparation method disclosed by the invention, the iron phosphate is better precipitated on the phosphate radical-manganese compound, so that the positive electrode material with better coating effect and better performance parameters is obtained, and meanwhile, the dissolution of Mn < 3 + > can be effectively inhibited by coating.

The present application provides a positive electrode material, a preparation method thereof, a positive electrode sheet, a battery and an electrical apparatus, and relates to the field of batteries. The positive electrode material comprises sodium iron phosphate pyrophosphate and a carbon coating layer covering the surface of same; and the positive electrode material contains an impurity phase sodium ferric phosphate, the mass ratio of the impurity phase sodium ferric phosphate in sodium iron phosphate pyrophosphate being 14% or below. The positive electrode material has a low content of the impurity phase sodium ferric phosphate, such that the initial charging capacity can be effectively improved, and the electrochemical performance of the positive electrode material is effectively improved.

The invention provides a high-compaction lithium iron phosphate positive electrode material and a preparation method thereof, and belongs to the field of recycling and repairing of lithium ion battery materials. The method comprises the following steps: step 1, dispersing iron phosphate, lithium carbonate, glucose, polyethylene glycol PEG and titanium dioxide into water to form first slurry; step 2, sanding the first slurry to a first predetermined particle size requirement, and then performing spray drying to obtain first solid powder; 3, roasting the first solid powder to obtain a sample A; step 4, dispersing iron phosphate, lithium carbonate, glucose and PEG into water to form second slurry; step 5, sanding the second slurry to a second predetermined particle size requirement, and then performing spray drying to obtain second solid powder; step 6, roasting the second solid powder to obtain a sample B; and step 7, mixing the sample A and the sample B, carrying out size mixing, carrying out sand milling, controlling to a third preset particle size requirement, carrying out spray drying, then carrying out roasting, and carrying out airflow crushing to obtain the high-compaction lithium iron phosphate positive electrode material.

The invention relates to the technical field of lithium ion battery positive electrode materials, and discloses a high-compaction and high-capacity lithium iron phosphate positive electrode material and a preparation method thereof, the positive electrode material has a three-level particle grading structure composed of large, medium and small particles, and the material contains a titanium element. The preparation method comprises the following steps: S1, mixing first iron phosphate and second iron phosphate with different iron-phosphorus molar ratios with a lithium source, a carbon source and an additive, then carrying out first sintering, and generating a stacking framework composed of large and medium particles in situ by utilizing the difference of internal growth activity of raw materials; and S2, mixing the sintered material obtained in the step S1 with titanium-containing iron phosphate, a lithium source and a carbon source in a specific ratio, and then carrying out secondary sintering to generate small particles to fill gaps of the frame, thereby finally forming the three-stage particle grading structure. Through programmed design of chemical properties of raw materials, accurate construction of a physical structure of a final product is achieved, the technological process is simplified, and the production cost is reduced.

The invention provides a modified ferric sodium phosphate pyrophosphate positive electrode material and a preparation method and application thereof.According to the preparation method, mature sanding, spray drying and calcining processes are adopted, and the ferric sodium phosphate pyrophosphate / carbon positive electrode material with a porous spherical structure and high phase purity is prepared by optimizing the combination of raw materials; and the performance breakthrough of high specific capacity, super-large rate capability and excellent super-large rate cycle performance is realized. The provided preparation method is simple and convenient in technological process, high in controllability and suitable for industrialization, the selected raw materials are wide in source and low in cost, the energy consumption in the technological process is relatively low, and the comprehensive production cost has remarkable advantages; the synthesized ferric sodium pyrophosphate / carbon positive electrode material obtains excellent dynamic performance, electrochemical performance and structural stability at an ultra-large rate at 20 DEG C based on special morphology characteristics and relatively high phase purity.

The invention relates to a method for selectively leaching and regenerating a positive electrode material from a waste lithium ion battery, and belongs to the technical field of lithium ion batteries. The method comprises the following steps: discharging, disassembling, crushing, calcining and screening the waste lithium ion battery, adding an obtained positive active material into an oxalic acid solution, and stirring and reacting at 60-80 DEG C under the irradiation of an ultraviolet lamp to obtain a leaching solution rich in metal elements and leaching residue iron phosphate; adding sodium carbonate into the leachate for reaction to obtain lithium carbonate; and ball-milling and mixing iron phosphate, lithium carbonate and a carbon source, drying and calcining to obtain the regenerated lithium iron phosphate positive electrode material. The oxalic acid system is catalyzed by ultraviolet light to generate hydroxyl free radicals with strong oxidizing property, so that the leaching efficiency of lithium is remarkably improved, and the dissolution of iron is inhibited, thereby realizing the efficient separation of lithium and iron. The leaching residue is high-purity iron phosphate, lithium in the leaching solution is recycled in the form of lithium carbonate, and the leaching residue and the lithium carbonate can be directly used for regenerating the lithium iron phosphate positive electrode material as precursors, so that the technological process is greatly simplified, and the production cost is reduced.

The invention relates to a lithium iron phosphate material, a preparation method thereof and a lithium ion battery, hydroxyl iron phosphate and hydroxyl iron phosphate containing metal doping elements are respectively used as phosphorus and iron sources to prepare a precursor, the compaction density of the lithium iron phosphate material is effectively improved based on a four-level grain size distribution design, and meanwhile, the capacity is ensured to be efficiently exerted. When the lithium iron phosphate material is used for preparing a lithium ion battery, the energy density, the rate capability and the cycle life of the battery can be remarkably improved, the development requirements of high-end application markets such as long endurance of electric automobiles and high efficiency of energy storage systems are met, and the lithium iron phosphate material has a good industrial application prospect.

The present invention provides a nano-scale sodium ferrophosphate doped with aluminum. 3+ , the sodium iron phosphate is a ferrophosphate nano-ore structure, and the particle size of the sodium iron phosphate is 50-700nm; the present invention also provides a method for preparing nano-scale ferrophosphate nano-ore type aluminum-doped sodium iron phosphate, comprising the following steps: grinding a phosphorus source, a sodium source, an iron source, and an aluminum source to obtain a mixed precursor, and sintering the mixed precursor to obtain a nano-scale ferrophosphate nano-ore type aluminum-doped sodium iron phosphate. The present invention also provides an application of a nano-scale ferrophosphate nano-ore type aluminum-doped sodium iron phosphate as a positive electrode material for preparing a sodium ion battery. The nano-scale ferrophosphate nano-ore type aluminum-doped sodium iron phosphate of the present invention is a positive electrode material for polyanion sodium ion batteries, which improves the electronic conductivity and energy density of sodium iron phosphate by doping, providing a positive electrode material for the next step of preparing a safer, more environmentally friendly, and low-cost sodium ion battery.