16 results about "Iron(II) phosphate" patented technology

This invention provides a lithium iron phosphate cathode material, its preparation method, and its application. The preparation method includes the following steps: (1) mixing ferrous salt and phosphorus source with an alcohol solvent, heating and stirring, and adding a first lithium source solution to obtain a mixed solution; adjusting the pH of the mixed solution to obtain a mixed precursor; (2) mixing a complexing agent, ferric salt, a second lithium source, phosphorus source, and surfactant with water, stirring to form a sol solution; mixing the mixed precursor obtained in step (1) with the sol solution, heating and stirring to obtain a gel precursor; (3) sintering the gel precursor to obtain the lithium iron phosphate cathode material; wherein the mixed precursor includes lithium phosphate and ferrous phosphate. This invention can achieve lithium iron phosphate gradation of different particle sizes through a single production line, improving the uniformity and compaction density of the material, and avoiding performance differences and poor stability between different batches.

The application provides a method for preparing cobalt-doped ferromanganese subphosphate by using iron phosphate sewage treatment sludge, and comprises the following steps: adding acid liquor into the iron phosphate sewage treatment sludge, performing acid leaching reaction, performing solid-liquid separation, and obtaining filtrate A; adding an extraction agent into the filtrate A, and performing extraction to obtain an extracted organic phase and a raffinate; performing multistage impurity removal on the raffinate to obtain a cobalt-manganese-phosphorus-containing solution, supplementing an iron source and a phosphorus source, and using a hydrothermal synthesis method to obtain a cobalt-doped ferromanganese subphosphate crude product, which is washed, dried and calcined to obtain the cobalt-doped ferromanganese subphosphate. The method can comprehensively recycle and utilize P, Mn and Co elements in the iron phosphate sewage treatment sludge, and reduces the production cost of the cobalt-doped ferromanganese subphosphate.

There is provided a method for producing ferrous sulphate and phosphoric acid comprising treating ferrous phosphate with sulphuric acid for obtaining ferrous sulphate and phosphoric acid. Additionally, there is provided a use of sulphuric acid for treating ferrous phosphate for obtaining ferrous sulphate and phosphoric acid.

The application provides a battery monomer, a preparation method thereof, a battery and a power utilization device, and belongs to the technical field of sodium batteries. The battery monomer comprises a positive electrode sheet, the positive electrode sheet comprises a positive electrode film layer, the positive electrode film layer comprises an active substance, the active substance comprises 96-99 wt% of sodium iron pyrophosphate phosphate, 0-1.9 wt% of sodium ferrous phosphate and 0.6-4 wt% of sodium iron pyrophosphate, and the mass ratio of sodium iron pyrophosphate in the active substance is greater than the mass ratio of sodium ferrous phosphate. The battery monomer of the application controls the content of the main phase and the impurity phase in the active substance in the above range, which can not only improve the compaction density of the positive electrode active material, but also is beneficial to improving the compaction density of the positive electrode sheet, and can improve the charge gram capacity and the discharge gram capacity of the positive electrode active material. When the mass ratio of sodium iron pyrophosphate in the active substance is greater than the mass ratio of sodium ferrous phosphate in the active substance, the energy density and the cycle performance of the battery monomer can be further improved.

The invention relates to a preparation method of high-purity ferrous phosphate and lithium iron phosphate, which comprises the following steps: heating dilute phosphoric acid, weighing iron powder, slowly adding the iron powder into the dilute phosphoric acid, carrying out stirring reaction, carrying out filter pressing to obtain reaction liquid, and taking filtrate to obtain a clear ferrous solution; when the temperature of the ferrous solution reaches a first temperature, adjusting the pH value of the reaction solution to a first numerical value by using ammonia water with a first concentration, preserving heat, heating the slurry, adjusting the pH value of the reaction solution to a second numerical value by using ammonia water with a second concentration, preserving heat to obtain ferrous phosphate octahydrate slurry, and carrying out filter pressing on the ferrous phosphate octahydrate slurry to obtain a ferrous phosphate octahydrate filter cake and a mother solution, the first concentration is lower than the second concentration, the first numerical value is lower than the second numerical value, and the first heat preservation time is shorter than the second heat preservation time. According to the method, phosphoric acid and iron powder are taken as raw materials, and the pH value of each stage of the reaction process is adjusted, so that the ferrous phosphate octahydrate with relatively high purity and relatively good crystallinity can be directly prepared.

The invention relates to ferrous phosphate based on mixed acid and iron powder and a preparation method and system thereof.The preparation method comprises the steps that dilute phosphoric acid and dilute sulfuric acid are mixed, pure iron powder is added into the mixed acid according to the ratio of n (p) to n (Fe) being (0.67-1): 1, and an iron dissolving reaction is conducted after a certain temperature is reached; taking the temperature as a starting point, sampling once every time period, analyzing the content of Fe < 2 + > in the obtained sample, and obtaining a ferrous liquid when the content of Fe < 2 + > in the sample reaches 3.5-5.0%; adding ammonia water into the ferrous liquid until the pH value of a reaction system reaches 5.0-6.5 to obtain slurry; and aging the slurry, and carrying out filter pressing, washing and drying to obtain the ferrous phosphate octahydrate. According to the method, the content of sulfate radicals in the obtained product can be effectively controlled while the use amount of phosphoric acid is reduced, the product quality is effectively improved, meanwhile, the thickness distribution uniformity of a ferrous phosphate octahydrate crystal lamellar structure is controlled, the thickness of the lamellar structure is reduced, the product quality is improved, and the compaction density of lithium iron phosphate is improved.

The present disclosure relates to the technical field of lithium ion battery cathode materials, and particularly discloses a method for preparing a carbon-coated lithium iron phosphate material from ferrous phosphate. The method comprises: mixing self-made ferrous phosphate with a carbon source, and sintering at a low temperature under nitrogen to remove a part of crystal water to obtain carbon-coated ferrous phosphate with a small amount of crystal water; evenly mixing ferrous phosphate with a lithium source, a phosphorus source and multiple carbon sources, and adjusting until a proper iron-to-phosphorus ratio is 0.960-0.975 and a carbon content is 1.5%-1.8%; subsequently drying slurry to obtain material powder; and sintering the material powder through a two-stage temperature rising curve, naturally cooling and then pulverizing to obtain the carbon-coated lithium iron phosphate material. The nano lithium iron phosphate material prepared by the method has high compaction, high capacity and long cycle performance.

This invention discloses a method for preparing layered iron phosphate and lithium iron phosphate. The method includes: preparing a ferrous phosphate mixture; filtering the ferrous phosphate mixture to obtain a refined ferrous phosphate filtrate; taking a portion of the refined ferrous phosphate filtrate and adding crude iron phosphate seed crystals to it, mixing evenly, and using it as a reaction base solution; continuously adding the remaining refined ferrous phosphate filtrate and an oxidant to the reaction base solution in a parallel flow, and carrying out a precipitation reaction at a specific temperature; the reaction product is washed and calcined to obtain battery-grade layered iron phosphate. This invention combines "seed induction" and "co-current co-precipitation" processes to control the nucleation and growth process of iron phosphate crystals, successfully preparing a uniform, large-particle-size layered iron phosphate product. This method can prepare uniform-size, tightly packed layered iron phosphate precursors, obtaining high-density lithium iron phosphate cathode materials, while improving the production yield and reducing washing water consumption, and has good process production application value.

This invention discloses a method for preparing lithium iron phosphate (LFP) materials, as well as the LFP materials and their applications, belonging to the field of LFP material technology. Addressing the problems of low volumetric energy density and high production costs associated with current LFP preparation methods, this invention provides a method for preparing LFP materials. Under co-precipitation and excess phosphorus source reaction conditions, a chelating agent is first used to chelate and inhibit grain growth to prepare nano-micron-sized hydrous ferrous phosphate salts. High-temperature decrystallization treatment is then used to form anhydrous ferrous phosphate with numerous defects. During calcination in a reducing atmosphere, high-performance LFP is synthesized through secondary phosphorus supplementation and the combined effects of sufficient lithium and carbon sources.

The application belongs to the field of waste battery material recycling, and particularly relates to a regenerated lithium iron phosphate material and a preparation method and application thereof, wherein the preparation method of the regenerated lithium iron phosphate material is as follows: waste lithium iron phosphate material is subjected to liquid phase treatment in an aqueous solution of a treating agent A, and then a first treated material is obtained by separation; the treating agent A is at least one of ammonia, sodium hydroxide, potassium hydroxide, EDTA, EDTA sodium salt and EDTA potassium salt; the first treated material and a treating agent B are subjected to calcination modification treatment at a temperature of 300-600 DEG C to obtain a modified material; the treating agent B comprises FeCl2; the modified material is mixed with phosphoric acid for leaching treatment to obtain ferrous phosphate slag and lithium liquid; the ferrous phosphate slag is subjected to lithiumization calcination to prepare the regenerated lithium iron phosphate material. The method can realize green recycling of waste LFP with low three wastes, and can directly regenerate the regenerated lithium iron phosphate with high performance, especially excellent fast charging performance.

This invention discloses a method for preparing low-viscosity basic ferric phosphate slurry and its product. The preparation method is as follows: ferrous salt solution and phosphate salt solution are prepared and simultaneously added to a reaction vessel to obtain basic ferrous phosphate slurry; an oxidant and a viscosity reducer are added for an oxidation reaction to obtain low-viscosity basic ferric phosphate slurry; the viscosity reducer is 5027W dispersant, anionic surfactant, sodium pyrophosphate, sodium hexametaphosphate, or chromium-free lignin sulfonate. This invention controls the crystal nucleation and growth rate through stepwise feeding, combined with the electrostatic and steric effects of the viscosity reducer, inducing primary particles to form a spherical structure and inhibiting agglomeration. The resulting slurry has a primary particle size of 55-80 nm, a secondary particle size of 7-10 μm, a viscosity ≤15.0 mPa·s, and a sedimentation efficiency P of 1.00-2.00. This slurry has good fluidity, and the anhydrous ferric phosphate prepared by subsequent crystal transformation has high purity, which is beneficial for improving ferric phosphate production efficiency and equipment lifespan.

This invention discloses a method for preparing composite sodium iron phosphate cathode material using iron slag solid waste, belonging to the field of sodium-ion battery cathode materials. The method specifically includes the following steps: Iron slag is crushed and sieved, dissolved in sulfuric acid, then iron powder is added and reacted, followed by filtration. The filtrate is demagnetized, heated to a specific temperature and held, and sodium hydroxide solution is slowly added dropwise to precipitate impurity ions. A flocculant is then added and filtered, resulting in solid-liquid separation. Phosphoric acid is added dropwise to the filtrate, followed by vacuum evaporation, concentration, cooling, and crystallization to obtain solid ferrous phosphate. Ferrous phosphate, sodium pyrophosphate, sucrose, oxalic acid, and pure water are stirred to form a uniform slurry. The slurry is ground, treated to remove iron, and then spray-dried to obtain precursor powder. The precursor powder is sintered at high temperature, pulverized by airflow, and treated to remove iron under an inert atmosphere to obtain the composite sodium iron phosphate cathode material. This invention uses iron slag as an iron source, turning waste into resources, reducing costs and increasing efficiency. The prepared material exhibits good rate capability and cycle performance.

The application belongs to the field of positive electrode materials, and particularly relates to a preparation method of a ferromanganese phosphate precursor. A ferrous source, a manganese source and a phosphate source are subjected to a precipitation reaction to obtain a ferromanganese phosphate precipitate. The ferromanganese phosphate precipitate is subjected to a micro-oxidation treatment in an oxygen-containing atmosphere in advance, and then the micro-oxidation product is subjected to a carbon thermal reduction to obtain the ferromanganese phosphate precursor. The application further includes a method for preparing a lithium manganese iron phosphate active material from the precursor and an application. The process can effectively remove anions in the bulk phase, optimize the physical and chemical structure, and further improve the performance of the material.

The application discloses a preparation method of ferrous phosphate octahydrate, which comprises the following steps: 1) preparing ferrous sulfate solution and phosphorus source solution, protecting by inert gas, adding the ferrous sulfate solution and the phosphorus source solution into a surfactant bottom solution, stirring, adding alkali solution until the pH of the reaction system is 2.5-4.0, stirring for the first-stage reaction, and performing suction filtration to obtain a filter cake; 2) slurring the filter cake according to the original solid content to obtain a reaction solution, protecting by inert gas, heating to 40-50 DEG C, adding alkali solution to adjust the pH of the solution to 4.5-6.0, stirring for the second-stage reaction, performing suction filtration, washing, and drying to obtain the ferrous phosphate octahydrate. The application controls the coprecipitation reaction by using stage temperature and segmented pH value, and performs solid-liquid separation by suction filtration under low pH value, so that the particle size, morphology and purity of the crystal can be controlled. After the first-stage reaction is completed, the slurry is subjected to the first suction filtration, and impurity elements such as Mg and Mn which are easy to precipitate in the system under high pH value are removed.

The application provides a method for preparing lithium manganese iron phosphate by using ferrous manganese phosphate composite ferrous phosphate, sequentially adding an iron source, a phosphorus source, an antioxidant and ammonia water into a reaction kettle, aging after the addition is completed, forming a mixed slurry; adding the mixed slurry into the reaction kettle and heating, then adding a lithium source, a phosphorus source and an alkaline solution, filtering and washing after the reaction to obtain a filter cake; mixing the iron source, the manganese source and the phosphorus source after stirring, then adding the antioxidant to obtain a mixed solution; putting the filter cake into the reaction kettle, adding the antioxidant, then simultaneously adding the mixed solution and an ammonia water solution dropwise, aging after the addition is completed, then washing with water and pressure filtering to obtain a ferrous manganese phosphate composite ferrous phosphate precursor; mixing the ferrous manganese phosphate composite ferrous phosphate precursor, nano-treated lithium phosphate, an organic carbon source, an additive and deionized water to form a mixture, and then performing processes of ball milling, drying, sintering, screening, batching and packaging to obtain a lithium manganese iron phosphate product.

This invention belongs to the field of new energy materials, and particularly relates to a lithium iron phosphate cathode material and its preparation method. The method includes: 1) adding ferrous phosphate to a magnesium chloride aqueous solution for Mg doping to obtain a precursor; 2) preparing a composite metal salt solution, adding the precursor to the composite metal salt solution for Ti / V doping to obtain an intermediate; 3) adding the intermediate to a phosphoric acid aqueous solution and mixing it with a carbon-nitrogen organic additive and a lithium source aqueous solution to prepare a pre-product solution; 4) calcining the pre-product solution to obtain the lithium iron phosphate cathode material. This invention effectively introduces metal ions at Li and Fe sites through gradient distribution and dynamic doping of multiple ions, achieving dual-site doping, and can introduce heterogeneous anions to further optimize the material. It significantly improves the low-temperature performance and rate performance of the lithium iron phosphate cathode material, and the preparation process is highly controllable, ensuring high product quality and high material utilization.