2809 results about "Iron phosphate" patented technology

The invention discloses a preparation method of a high-compaction-density lithium iron phosphate material, through grading of large and small particle lithium iron phosphate, optimization of a sintering process and reasonable selection of a carbon source and a titanium dopant, the compaction density and the electrochemical performance of the material are remarkably improved, and the preparation method specifically comprises the following steps: mixing iron phosphate, lithium carbonate, the carbon source and auxiliary materials; the preparation method comprises the following steps: carrying out coarse grinding and fine grinding, respectively preparing large-particle lithium iron phosphate and small-particle lithium iron phosphate (a material A and a material B) by adopting spray drying and high-temperature calcination processes, mixing the material A and the material B according to a ratio, adding auxiliary materials, grinding, further carrying out spray drying, calcining and crushing to obtain a final lithium iron phosphate product, and the maximum compaction density of the prepared material can reach 2.712 g / cm < 3 >. According to the present invention, the maximum 1C discharge specific capacity can achieve 140.5 mAh / g, the maximum 1C 3.2 V discharge platform retention rate is 91.4%, and the prepared lithium ion battery negative electrode material has characteristics of excellent conductivity, high discharge capacity and good cycle stability, and is suitable for power batteries and energy storage batteries.

The invention provides a battery monomer, a battery device and a power utilization device. The battery monomer comprises an electrode assembly, wherein the electrode assembly comprises a positive plate, a negative plate and a non-aqueous electrolyte; the positive plate comprises a positive current collector and a positive film layer, and the negative plate comprises a negative current collector and a negative film layer; the positive electrode film layer comprises a positive electrode active material, and the positive electrode active material comprises a lithium manganese iron phosphate material and a nickel cobalt lithium manganate material; in the nickel cobalt lithium manganate material, the molar ratio of Ni in the sum of the three elements of Ni, Co and Mn is 0.5-0.95; the non-aqueous electrolyte comprises vinylene carbonate, and the mass content of the vinylene carbonate in the non-aqueous electrolyte is 0.5%-2%; the non-aqueous electrolyte comprises at least one of linear carbonic ester and linear carboxylic ester, and the conductivity of the non-aqueous electrolyte is 9-14 mS / cm. The energy density, the cycle performance and the power performance of the battery monomer are improved at the same time.

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 provides a lithium manganese iron phosphate battery. The battery comprises a positive pole piece, a negative pole piece and a non-aqueous electrolyte, the positive pole piece comprises a positive active material and a positive active coating arranged on at least one surface of the positive active material; the positive electrode active material comprises lithium manganese iron phosphate LiMnxFe1-xPO4 coated with a carbon coating layer, and x is more than or equal to 0.5 and less than or equal to 0.8; the negative pole piece comprises a negative active material and a negative active coating arranged on at least one surface of the negative active material; the battery satisfies the following relational expressions: 4.5 < = (a / 20 + d) / (b + c) < = 12.8; a is a coated diaphragm resistor of the positive pole piece; b is the compaction density of the positive pole piece; c is the mass percentage content of vinylene carbonate in the positive electrode slurry; and d is the mass percentage content of the lithium bis (fluorosulfonyl) imide in the non-aqueous electrolyte. By optimizing the composition of the lithium ion battery, the low-temperature discharge performance of the battery is improved, and meanwhile, the high-temperature cycle performance is considered.

Provided are a lithium manganese iron phosphate material and a preparation method therefor, a positive electrode sheet, and a lithium ion battery. The lithium manganese iron phosphate material comprises a core and a coating layer that coats the surface of the core. The chemical formula of the material of the core is LiaMnbFecMdPO4, wherein M comprises at least one element among magnesium, calcium, strontium, cobalt, titanium, zirconium, molybdenum, vanadium, niobium, nickel, scandium, chromium, copper, zinc, beryllium, lanthanum and aluminum. The coating layer is formed by sintering a carbon source, and the carbon coating layer comprises graphitized carbon.

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 discloses a preparation method and application of an amorphous nickel-cobalt-iron phosphate anode catalyst, and belongs to the technical field of alkaline water electrolysis hydrogen production, the preparation method comprises the following steps: (1) dissolving transition metal salt in a solvent, and stirring to obtain a metal salt solution; (2) dissolving phosphate in a solvent, and stirring to obtain a phosphate solution; and (3) adding the phosphate solution into the metal salt solution for reaction, washing with deionized water and ethanol, centrifugally separating, and drying to obtain the amorphous nickel-cobalt-iron phosphate anode catalyst. According to the preparation method and application of the amorphous nickel-cobalt-iron phosphate anode catalyst, process safety improvement and environmental friendliness optimization are achieved through an all-water-phase green synthesis system, the obtained catalyst shows excellent performance in an AEM electrolytic cell, the cell voltage is only 1.87 V under the current density of 2 A / cm, and the method has remarkable industrial application prospects.

The invention discloses a gradient composite coated modified lithium manganese iron phosphate positive electrode material and a preparation method thereof, and belongs to the technical field of positive electrode materials. An LMFP precursor is pretreated through a citric acid-ethanol mixed solution, an active crystal face is exposed, and then a three-dimensional gradient coating structure of a polydopamine (PDA) chemical bonding layer, an MXene nanosheet middle layer and a polyaniline (PANI) conductive outer layer is sequentially constructed on the surface of the material, so that the electronic conductivity of the lithium manganese iron phosphate positive electrode material is increased to 10 <-3 > S / cm magnitude, and the performance of the lithium manganese iron phosphate positive electrode material is improved. The capacity retention ratio (1C) of 500 cycles is larger than 90%, the coating layer is not prone to falling off, and meanwhile dissolution of manganese ions is effectively inhibited.

The invention discloses a method for regenerating waste lithium iron phosphate into a lithium manganese iron phosphate positive electrode material under assistance of element doping. According to the method, the waste lithium iron phosphate is successfully regenerated into the lithium manganese iron phosphate material with excellent performance through solid-phase sintering and element doping. Compared with a traditional repairing and regenerating method, the method has the advantages that upgrading and regenerating of the waste lithium iron phosphate are realized, and the market competitiveness of regenerated products is improved. Compared with other methods, the method does not need an acid leaching step, and the recovery process is simpler and more environment-friendly. And an element doping modification means is introduced, so that the performance of the regenerated lithium manganese iron phosphate material is further improved. The invention aims to provide a green, efficient and high-valued method for upgrading and regenerating the waste lithium iron phosphate positive electrode material into the lithium iron manganese phosphate positive electrode material with industrial application prospects.

A waste lithium iron phosphate battery recovery method. The method comprises selective leaching, deep purification and battery-grade iron phosphate preparation. By means of selective leaching, lithium and ferrophosphorus materials are separated in one step, and leaching conditions are optimized to prevent difficulty in leaching ferrophosphorus and inability to dissolve impurities caused by transformation of a ferrophosphorus crystal form; obtained ferrophosphorus graphite slag is used as a raw material for synthesizing iron phosphate, and is subjected to further purification and impurity removal (deep purification) by means of a dilute strong acid and an alkali solution, thereby reducing subsequent complex processes such as liquid phase impurity removal of ferrophosphorus liquid, and finally, the purified ferrophosphorus graphite slag is subjected to acid leaching to obtain high-purity filtrate containing phosphorus and iron which can be used for directly synthesizing battery-grade iron phosphate. In the whole process, a small amount of acid is used, a high-impurity-content battery material can be treated, the impurity element removal efficiency is high, the process is short, and the economic benefit is high.

The invention discloses a method for recovering lithium phosphate from lithium iron phosphate black powder. The method comprises the following steps: mixing black powder recovered from waste lithium iron phosphate batteries with sodium persulfate, and calcining; adding water into the obtained calcined product, dissolving, filtering to obtain water extract A and leaching residues, washing the leaching residues with water, and calcining at high temperature to obtain battery-grade iron phosphate; adding a sodium hydroxide solution into the water extract A, and reacting to obtain a water extract B; adding a trisodium phosphate solution into the water immersion liquid B, fully reacting, performing suction filtration to obtain lithium phosphate and filtrate, and cleaning and drying the lithium phosphate to obtain battery-grade lithium phosphate; and freezing and denitrifying the filtrate to obtain a denitrified solution, and adding the denitrified solution into the sodium hydroxide solution for recycling. The method does not generate wastes, recycles the filtrate in the whole process, theoretically realizes zero loss of the lithium element, prevents the iron element from entering the solution, simplifies the preparation steps of the lithium phosphate, and has the advantages of cost reduction and environmental protection.

The invention provides a battery monomer, a battery device and a power utilization device. The battery monomer comprises an electrode assembly, wherein the electrode assembly comprises a positive plate, a negative plate and an isolating membrane positioned between the positive plate and the negative plate; the negative plate comprises a negative current collector and a negative active layer located on at least one side of the negative current collector, the negative active layer comprises a negative material, the negative material comprises a negative active material, and the negative active material comprises graphite; the positive plate comprises a positive current collector and a positive active layer positioned on at least one side of the positive current collector, the positive active layer comprises a positive material, the positive material comprises a positive active material, and the positive active material comprises lithium iron phosphate and a lithium manganese iron phosphate material; the surface density of the positive electrode active layer is 200 to 370 mg / 1540.25 mm < 2 >; and when the battery monomer is in a 100% SOC state, the compaction density of the positive electrode active layer is 2.27-2.67 g / cm < 3 >. The battery monomer has the advantages of low cost, high energy density and long cycle life.

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.

The invention discloses a recovery technology for waste lithium iron phosphate batteries, and aims to prepare high-purity iron phosphate and lithium phosphate and comprehensively recover valuable metals such as iron, aluminum and copper in the high-purity iron phosphate and lithium phosphate. The method mainly comprises the following steps that waste lithium iron phosphate battery powder is subjected to oxidizing roasting to obtain roasted battery powder, the roasted battery powder is mixed with phosphoric acid and hydrogen peroxide in different molar ratios, the liquid-solid ratio is adjusted through deionized water, oxidizing leaching is conducted, and lithium-rich liquid and primary leaching residues are obtained; the secondary leaching residues are subjected to phosphoric acid activation, and high-purity iron phosphate dihydrate is obtained after the pH is adjusted; and performing metal ion precipitation on the lithium-rich liquid by adjusting the pH value, and finally performing high-temperature calcination to obtain high-purity lithium phosphate. The method not only realizes efficient leaching and separation of lithium, but also improves the precipitation efficiency of iron phosphate, solves the problems of low metal resource recovery rate and serious process pollution in the prior art, and is suitable for large-scale treatment of waste lithium iron phosphate batteries.

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 provides a method for recycling lithium iron phosphate, which comprises the following steps: S1, obtaining lithium iron phosphate black powder, and washing the lithium iron phosphate black powder by using alkali liquor to obtain aluminum-removed black powder and aluminum-containing lithium filtrate; s2, the aluminum-removed black powder is subjected to acid leaching treatment with acid liquor, and acid leaching liquor is obtained; s3, carrying out reduction precipitation treatment on the acid leaching solution by using a composite reducing agent to obtain a copper-removed leaching solution and solid-phase copper-containing slag; s4, adding a phosphorus source and an oxidizing agent into the copper-removed leaching solution, adding alkali to adjust the pH value, and carrying out oxidation precipitation treatment to obtain iron phosphate precipitate and a first lithium-containing solution; and S5, adjusting the pH value of the aluminum-lithium-containing filtrate in the step S1 by using an acid solution to obtain aluminum filter residues and a second lithium-containing solution. According to the method, iron phosphate with relatively high purity can be obtained; meanwhile, the obtained first lithium-containing solution and the second lithium-containing solution are relatively low in impurity ion content and can be used for obtaining a lithium salt product with relatively high purity.

The invention relates to the technical field of preparation of iron phosphate materials, in particular to a method for doping iron phosphate with titanium, which comprises the following steps: 1, dissolving a titanium dioxide by-product ferrous sulfate powder in water to prepare a titanium-containing iron source solution; 2, adding water into the reaction kettle, and stirring; 3, adding the titanium-containing iron source solution, the phosphorus source solution, ammonia water and an oxidizing agent into a reaction kettle to prepare primary slurry; 4, carrying out filter pressing on the primary slurry, washing until the conductivity is less than or equal to 2000us / cm, and then adding water to prepare secondary slurry; 5, phosphoric acid is added into the reaction kettle for bottoming, and the temperature is increased to 60-70 DEG C; 6, adding the secondary slurry into the reaction kettle, and carrying out heat preservation reaction on the secondary slurry and phosphoric acid; and 7, filtering the reaction product obtained in the step 6, washing until the conductivity is less than or equal to 500us / cm, and then drying and sintering. According to the method, the titanium doping technological process is simplified, and meanwhile the titanium element utilization rate in the titanium dioxide by-product and the purity of the titanium-doped iron phosphate product are improved.

A positive electrode material, and a preparation method therefor and the use thereof. The positive electrode material has a core-shell structure, wherein a core part comprises a carbon-coated Cu2+-doped iron-based phosphate sodium-ion material, and a shell layer is CuO. The iron-based phosphate sodium-ion material is selected from ferric sodium pyrophosphate, ferric sodium phosphate or ferric sodium phosphate pyrophosphate. The preparation method for the positive electrode material comprises: mixing the carbon-coated iron-based phosphate sodium-ion material, a copper source and a first solvent, and then subjecting the mixture to first drying and first calcination.

The invention belongs to the technical field of lithium ion battery materials, and discloses a bismuth silicate coated lithium ferric manganese phosphate material, a preparation method thereof and a lithium ion battery. The bismuth silicate coated lithium ferric manganese phosphate material comprises lithium ferric manganese phosphate and a coating layer coating at least part of the surface of the lithium ferric manganese phosphate, and the coating layer is made of bismuth silicate. Carrying out ball-milling mixing on the ferric manganese phosphate material, a lithium source, a carbon source and water to obtain mixed slurry; performing low-temperature spray drying on the mixed slurry to obtain a spray material; and carrying out wet mixing on a silicon source, a bismuth source and the spray material, carrying out high-temperature pyrolysis on the wet-mixed material in a spray pyrolysis furnace, and sintering to obtain the bismuth silicate coated lithium ferric manganese phosphate material. When the bismuth silicate coated lithium ferric manganese phosphate material is used as a positive electrode active material of a lithium ion battery, the high-temperature cycle performance of the battery can be improved while the high discharge capacity of the battery is ensured.

A method for preparing modified iron(III) phosphate, comprising the following steps: (1) preparing NH2-MIL-53(Al) nanoparticles, mixing the nanoparticles with a solvent, adding an acid solution, and heating and stirring the mixture to obtain hollow NH2-MIL-53(Al) powder; (2) using the hollow NH2-MIL-53(Al) powder to prepare a dispersion, mixing the dispersion with an iron salt solution, stirring and then drying the mixture, mixing the resulting powder with a phosphorus source solution, controlling the pH, and carrying out a reaction; and (3) carrying out sintering treatment on a material resulting from aging to obtain the modified iron(III) phosphate. Provided are iron(III) phosphate prepared according to the method and a positive electrode material. In the method, a hollow metal organic framework nanomaterial is used as a template to provide a micro reaction area for the synthesis of iron(III) phosphate, so that the microscopic morphology of the prepared iron(III) phosphate is restrained and controlled to prepare nanoscale iron(III) phosphate having a polyhedral structure.

The invention provides a composite sodium ferric phosphate positive electrode material, a precursor and a preparation method thereof, and a sodium ion battery, and belongs to the technical field of inorganic material preparation. Amorphous iron hydrogen phosphate is successfully prepared by innovatively adopting a wet chemical method, the amorphous iron hydrogen phosphate precursor is mixed with the sodium salt, the phosphorus source and the carbon source, the composite sodium iron phosphate positive electrode material is prepared through a solid-phase sintering process, and the prepared composite sodium iron phosphate positive electrode material is high in purity, high in compaction density and good in stability. The structure stability is good, and the specific discharge capacity and the rate capability are excellent; by adopting the positive electrode material, the reversible specific capacity and the service life of the sodium-ion battery can be effectively improved, and high-quality sodium-ion battery supply is provided for the field of energy storage.

The invention provides a composite lithium manganese iron phosphate positive electrode material and a preparation method and application thereof, the preparation method comprises the following steps: (1) mixing a lithium source, an iron source, a manganese source, a phosphorus source, a fluxing agent, a dispersing agent and a solvent to obtain mixed slurry, spray-drying the mixed slurry, and calcining to obtain a lithium manganese iron phosphate intermediate; and (2) mixing the lithium iron manganese phosphate intermediate, a lithium source, a dispersing agent and a solvent to obtain mixed slurry, performing spray drying on the mixed slurry, and performing calcination treatment to obtain the composite lithium iron manganese phosphate positive electrode material. According to the method, the lithium iron manganese phosphate positive electrode material is prepared in a sectional manner, and the lithium iron manganese phosphate positive electrode material which is compact in structure, good in structural stability, high in grain strength, uniform in particle size distribution and high in compaction density can be prepared by adjusting the adding types of the materials and the adding amount of each section.

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 provides a lithium manganese iron phosphate precursor hydrate which comprises a mixture of manganese phosphorus ore phase manganese manganese phosphate and ammonium manganese iron phosphate, and the molar ratio of the manganese phosphorus ore phase manganese manganese phosphate to the ammonium manganese iron phosphate is (1: 9)-(1: 1). A precursor material obtained by roasting the precursor hydrate is uniform in manganese and iron element distribution and good in processability, and lithium manganese iron phosphate with relatively high compaction density, relatively high capacity and better comprehensive performance can be prepared. The invention also provides a preparation method of the lithium iron manganese phosphate precursor hydrate, a lithium iron manganese phosphate precursor, lithium iron manganese phosphate and a secondary battery.

The invention provides a Na / P double-site doped phosphoric acid ferric sodium pyrophosphate / carbon positive electrode active material and a preparation method and application of the Na / P double-site doped phosphoric acid ferric sodium pyrophosphate / carbon positive electrode active material. The material comprises a Na / P double-site doped ferric sodium pyrophosphate base material and a carbon coating layer coating the surface of the base material, the general formula of the base material is Na (4-x) MxFe3 (PO4) 2-y (QO4) y (P2O7), 0 lt, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 X is less than or equal to 0.4, 0lt; y < = 0.2; m is at least one of K, Li, Mg, Ca and Sr, and Q is at least one of Si, Ge, B and S; specific elements are introduced to the Na site and the P site to form a synergistic doping structure, so that the crystal structure and charge distribution are regulated and controlled, and the electrochemical performance of the material is further improved; the material disclosed by the invention is simple and convenient to prepare, wide in raw material source, suitable for electrochemical energy storage systems such as sodium ion batteries and the like, and excellent in rate capability and long in cycle life.

The invention discloses a lithium manganese iron phosphate positive electrode material coated with a carbon layer based on a CVD (chemical vapor deposition) method and a preparation method, the preparation method comprises the following steps: forming a uniform carbon coating layer on a lithium manganese iron phosphate precursor based on a CVD coating process, mixing the lithium manganese iron phosphate precursor with the uniform carbon coating layer and a lithium salt, and carrying out co-sintering, and the lithium salt can permeate through the carbon layer to form a lithium-doped uniform carbon coating layer. According to the method, the coating effect is improved, the problem that uniform coating cannot be formed on the surface of the precursor in a traditional carbon coating process is effectively solved, precipitation of trivalent manganese ions at a high temperature can be slowed down, the problem that the capacity exertion is reduced due to the fact that an amorphous carbon layer formed by a CVD cracking coating process affects lithium ion deintercalation is solved, and the performance of the lithium ion battery is improved. The safety and the service life of the battery are improved.

The invention relates to a process for recycling and regenerating a waste lithium iron phosphate positive electrode material by using a specific chelating agent. The method comprises the following steps: carrying out heat treatment on a waste lithium iron phosphate positive electrode material, putting separated waste lithium iron phosphate powder into a ball milling tank, adding organic acid and a chelating agent, and carrying out ball milling; after the ball milling is finished, adding hydrogen peroxide, uniformly stirring and mixing, adjusting the pH value to 2-3 by using nitric acid, and filtering to obtain a filter cake which is iron phosphate; adding saturated sodium carbonate into the filtrate, precipitating, and recovering lithium carbonate; putting the iron phosphate, the lithium carbonate, the iron source, the lithium source and the phosphorus source in the step S3 into a ball mill for ball milling, and performing high-temperature solid-phase sintering after ball milling to obtain a regenerated lithium iron phosphate material; the chelating agent disclosed by the invention is prepared from (9ci)-2-(2-propenyl)-1-cyclopentene-1-carboxylic acid, 2-mercaptobenzimidazole carboxylic acid, an ethylene boric anhydride pyridine complex and potassium persulfate. The regenerated lithium iron phosphate material prepared by the method has excellent electrochemical performance.

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 metal composite lithium iron phosphate solid-phase deposition coated lithium manganese iron phosphate positive electrode material and a preparation method thereof, and belongs to the technical field of lithium ion battery positive electrode materials. The preparation method of the metal composite lithium iron phosphate solid-phase deposition coated lithium iron manganese phosphate positive electrode material comprises the following steps: S1, preparing a lithium iron manganese phosphate material and sintering; s2, grinding lithium iron phosphate into nano particles, and mixing the nano particles with a sugar source to form lithium iron phosphate nano slurry; s3, transferring into a CVD (Chemical Vapor Deposition) fluidized bed in the lithium manganese iron phosphate cooling and sintering stage, spraying lithium iron phosphate nano slurry, gasifying and drying the lithium iron phosphate material, and coating the surface of the lithium manganese iron phosphate with the lithium iron phosphate material through solid-phase deposition; and S4, carrying out composite coating of carbon and metal oxide on the lithium manganese iron phosphate coated with the lithium iron phosphate to obtain the lithium manganese iron phosphate coated with the lithium iron phosphate. According to the invention, the problem of poor uniformity of lithium iron phosphate coated lithium iron manganese phosphate is solved, the electrical property of lithium iron manganese phosphate is improved, the ferromanganese dissolution is improved, and the cycle performance is improved.