8 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.

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.

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.

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.

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.