CN112938916B - Synthesis method for preparing lithium iron phosphate precursor with high cost performance by controlling crystallization - Google Patents
Synthesis method for preparing lithium iron phosphate precursor with high cost performance by controlling crystallization Download PDFInfo
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Abstract
The application discloses a synthesis method for preparing a lithium iron phosphate precursor with high cost performance by controlling crystallization, which relates to the technical field of battery materials and comprises the following steps: s1) preparing a mixed solution of lithium salt, ferrous salt and phosphate; the pH of the mixed solution is less than 4; s2) stirring the mixed solution obtained in the step S1) at room temperature, slowly adding alkali to adjust the pH value to 6-7, heating and pressurizing to set temperature and pressure, and carrying out heat preservation and pressure maintaining reaction for 1-6 h; s3) filtering to obtain solid precipitate, and washing and drying to obtain a lithium iron phosphate precursor; wherein the set temperature is 80-120 ℃; the set pressure is normal pressure to 0.3MPa. The synthesis method of the lithium iron phosphate precursor disclosed by the application is simple and rapid, the reaction conditions are easy to control, the popularization and the application are convenient, and the industrial implementation is facilitated.
Description
Technical Field
The application relates to the technical field of battery materials, in particular to a synthesis method for preparing a lithium iron phosphate precursor with high cost performance by controlling crystallization.
Background
In 1997, padhi et al studied LiFePO with a regular olivine structure 4 The theoretical capacity of the material reaches 170mAh/g, the material has excellent charge-discharge cycle performance, low price, excellent high-temperature performance, environmental protection and no pollution, thus LiFePO O 4 Is considered to be a very ideal positive electrode material for a group ion battery. The existing lithium iron phosphate production technology can be generally divided into a solid-phase method and a liquid-phase method, wherein the solid-phase method is the most widely used and most-studied method for synthesizing lithium iron phosphate at present. The iron source used in the solid phase synthesis method is typically iron oxide, iron phosphate, or the like, the lithium source is typically lithium carbonate, lithium hydroxide, or the like, and the phosphorus source is typically dihydrogen phosphate, or the like. The raw materials are mixed according to the stoichiometric ratio and sintered under the protection of protective gas nitrogen, and the key of the reaction method is whether the raw materials are uniformly mixed or not because of the large variety of the raw materials. The method has the greatest advantages of simple equipment and process, easy control of preparation conditions and suitability for industrial production. The defects are that the solid phase of the raw material is uneven, the consistency of the product batch is poor, and the electric performance of the product is not good. Compared with the liquid phase method, the latter method has the advantages of more uniform mixing of the initial raw materials on the molecular level, easy control of crystal form and particle size, uniform phase, small particle size of powder and simple process. Compared with the solid phase synthesis method, the method has the indisputable advantage, but the industrialization is more difficult than the solid phase synthesis method due to the higher requirement on the control of the production conditions.
Disclosure of Invention
The application aims to solve the problems that the liquid phase method for preparing lithium iron phosphate in the prior art has high requirement on control of production conditions and is difficult to industrialize, and provides a synthesis method for preparing a lithium iron phosphate precursor with high cost performance by controlling crystallization, wherein the synthesis method is simple in production procedure.
In order to achieve the above object, the present application provides the following technical solutions: a synthesis method for preparing a lithium iron phosphate precursor with high cost performance by controlling crystallization comprises the following steps:
s1) preparing a mixed solution of lithium salt, ferrous salt and phosphate; the pH of the mixed solution is less than 4;
s2) stirring the mixed solution obtained in the step S1) at room temperature, slowly adding alkali to adjust the pH value to 6-7, heating and pressurizing to set temperature and pressure, and carrying out heat preservation and pressure maintaining reaction for 1-6 h;
s3) filtering to obtain solid precipitate, and washing and drying to obtain a lithium iron phosphate precursor;
wherein the set temperature is 80-120 ℃; the set pressure is normal pressure to 0.3MPa.
In the technical scheme, lithium salt, ferrous salt and phosphate are directly reacted at the set temperature and pressure to obtain the lithium iron phosphate precursor, other additives are not required to be added, an inert gas environment is not required to be maintained in the reaction process, the control of the production conditions for preparing the lithium iron phosphate precursor is reduced, and the cost investment of process links, equipment and other raw materials is reduced; meanwhile, the investment of other raw materials is reduced, so that the components of the byproducts are more single, the later-stage byproduct treatment is facilitated, and the production cost is reduced. In addition, the reaction temperature of the lithium salt, the ferrous salt and the phosphate is 80-120, the reaction pressure is small, the production control is convenient, and the popularization and the application of the synthesis method are facilitated.
Further, in S1), the mixed solution is prepared by: preparing lithium salt water solution, ferrous salt water solution and phosphate salt water solution respectively by deionized water, adding acid to adjust the pH values of the lithium salt water solution, the ferrous salt water solution and the phosphate salt water solution to be less than 4 respectively, and stirring and mixing the lithium salt water solution, the ferrous salt water solution and the phosphate salt water solution uniformly to obtain a mixed solution of lithium salt, ferrous salt and phosphate.
Further, in the step S1), the concentration of ferrous ions in the mixed solution is 0.1-1 mol/L; the molar ratio of the lithium ions to the ferrous ions to the phosphate ions is 1-3:1:1.
Further, the acid used for adjusting the lithium salt water solution, the ferrous salt water solution and the phosphate salt water solution is any one or more of sulfuric acid, hydrochloric acid and nitric acid; preferably sulfuric acid.
Further, in the step S1), the lithium salt is one or more of lithium sulfate, lithium chloride, lithium nitrate, lithium carbonate and lithium phosphate; lithium sulfate and lithium phosphate are preferred.
Further, in the step S1), the ferrous salt is one or more of ferrous sulfate, ferrous chloride and ferrous nitrate; ferrous sulfate is preferred.
Further, in the step S1), the phosphate is one or more of monoammonium phosphate, sodium phosphate, lithium phosphate and lithium dihydrogen phosphate; lithium phosphate is preferred.
Further, in S2), the alkali is one or two of sodium hydroxide and ammonia water; sodium hydroxide is preferred.
Further, the synthesis method further comprises the step of S4) recovering residual lithium ions in the mother liquor: and (3) adding phosphate or phosphoric acid into the filtrate obtained in the step (S3), adding alkali to adjust the pH value to 11-12, precipitating and separating lithium phosphate solid, and recovering lithium phosphate. The recovered lithium phosphate can be continuously used for preparing the lithium iron phosphate precursor, so that the production cost is saved, and the treatment cost of the production waste liquid is reduced.
Further, in S4), after adding phosphate or phosphoric acid, the molar ratio of phosphorus to lithium in the filtrate is not less than 1:3.
Compared with the prior art, the application has the following beneficial effects:
the application discloses a synthesis method for preparing a lithium iron phosphate precursor with high cost performance by controlling crystallization, which takes lithium salt, ferrous salt and phosphate as raw materials, adopts a liquid phase method to directly react at the temperature of 80-120 ℃ under the condition of normal pressure-0.3 MPa and the pH value of 6-7 to obtain the lithium iron phosphate precursor, is simple and quick, has easily controlled reaction conditions, is convenient to popularize and apply, and is beneficial to industrialized implementation; meanwhile, as no additives such as reducing agent and the like are needed to be additionally added, and an inert gas environment is also not needed to be arranged, the production process procedures are reduced, the raw material cost and the equipment cost are reduced, and the production cost of lithium iron phosphate is reduced; in addition, the complex and changeable byproducts and residual raw materials in a reaction system are reduced, and the treatment cost of the byproducts and the waste liquid is reduced. The application also discloses a recycling step of lithium ions in the reaction waste liquid, which saves the production cost and reduces the treatment cost of the production waste liquid.
The lithium iron phosphate precursor prepared by the synthesis method disclosed by the application has controllable particle size and high batch stability; the lithium iron phosphate precursor is sintered to obtain the lithium iron phosphate with high capacity, the normal-temperature buckling 0.1C charging capacity is not lower than 164mAh/g, the discharge capacity is not lower than 158mAh/g, the initial effect is not lower than 96%, and the batch stability is high.
Drawings
FIG. 1 is a flow chart of a synthesis method for preparing a cost-effective lithium iron phosphate precursor by controlled crystallization disclosed in some embodiments of the application;
FIG. 2 is a Scanning Electron Microscope (SEM) image of a lithium iron phosphate precursor prepared according to example 1 of the present application;
fig. 3 is an X-ray diffraction (XRD) pattern of a lithium iron phosphate precursor prepared in example 1 of the present application.
Detailed Description
The present application will be described in further detail with reference to test examples and specific embodiments. It should not be construed that the scope of the above subject matter of the present application is limited to the following embodiments, and all techniques realized based on the present application are within the scope of the present application.
Example 1
In the embodiment, lithium sulfate, ferrous sulfate and monoammonium phosphate are used as raw materials, sulfuric acid and sodium hydroxide are used as acid and alkali for regulating the pH value to prepare the lithium iron phosphate precursor, and referring to FIG. 1, the specific preparation method is as follows:
s1) preparing 300L of lithium sulfate solution with the lithium ion concentration of 0.9mol/L by deionized water, and regulating the pH value to be less than 4 by sulfuric acid; preparing 300L of ferrous sulfate solution with ferrous ion concentration of 0.3mol/L by deionized water, and regulating the pH value to be less than 4 by sulfuric acid; preparing 300L monoammonium phosphate solution with phosphate radical ion concentration of 0.3mol/L by deionized water, and regulating pH value to be less than 4 by sulfuric acid;
sequentially adding a lithium salt aqueous solution, a ferrous salt aqueous solution and a phosphate aqueous solution into a 1000L reaction kettle, and uniformly stirring and mixing to obtain a mixed solution;
s2) slowly adding sodium hydroxide solution into the reaction kettle until the pH value is 7, heating to 80 ℃, and keeping the reaction kettle in an unsealed state, so that the reaction kettle is kept at normal pressure, and after the reaction is carried out for 6 hours under the condition of heat preservation and pressure maintaining, the reaction is completed;
s3) filtering the reaction system to perform solid-liquid separation, washing the solid obtained by filtering with deionized water for at least three times, and drying to obtain a product A;
and S4) collecting the mother solution and the washing solution obtained by filtering in a stirring tank, adding phosphoric acid until the molar ratio of the phosphorus to the lithium in the stirring tank is slightly higher than 1:3, adding sodium hydroxide solution to adjust the PH value to be 12, and then carrying out solid-liquid separation and drying to obtain the lithium phosphate.
Example 2
In this embodiment, lithium chloride, ferrous chloride and sodium phosphate are used as raw materials, hydrochloric acid and ammonia water are used as acid and alkali for adjusting the pH value to prepare a lithium iron phosphate precursor, and the specific preparation method is as follows:
s1) preparing 300L of lithium chloride solution with the lithium ion concentration of 3mol/L by deionized water, and regulating the pH value to be less than 4 by hydrochloric acid; preparing 300L of ferrous chloride solution with the ferrous ion concentration of 3mol/L by deionized water, and regulating the pH value to be less than 4 by hydrochloric acid; preparing 300L of sodium phosphate solution with phosphate radical ion concentration of 3mol/L by deionized water, and regulating pH value to be less than 4 by hydrochloric acid;
sequentially adding a lithium salt aqueous solution, a ferrous salt aqueous solution and a phosphate aqueous solution into a 1000L reaction kettle, and uniformly stirring and mixing to obtain a mixed solution;
s2) slowly adding ammonia water into the reaction kettle until the pH value is 6.5, heating to 100 ℃, keeping the reaction kettle sealed, keeping the pressure in the reaction kettle stable at 0.3MPa, keeping the temperature and the pressure for 1h, and finishing the reaction;
s3) filtering the reaction system to perform solid-liquid separation, washing the solid obtained by filtering with deionized water for at least three times, and drying to obtain a product B;
and S4) collecting the mother solution and the washing solution obtained by filtering in a stirring tank, adding phosphoric acid until the molar ratio of the phosphorus to the lithium in the stirring tank is slightly higher than 1:3, adding ammonia water to adjust the PH to be 11, and then carrying out solid-liquid separation and drying to obtain the lithium phosphate.
Example 3
In this embodiment, lithium nitrate, ferrous nitrate and sodium phosphate are used as raw materials, and nitric acid and sodium hydroxide are used as acids and bases for adjusting the pH value to prepare a lithium iron phosphate precursor, and the specific preparation method is as follows:
s1) preparing 300L of lithium nitrate solution with the lithium ion concentration of 3mol/L by deionized water, and adjusting the pH value to be less than 4 by nitric acid; preparing 300L of ferrous nitrate solution with ferrous ion concentration of 2mol/L by deionized water, and regulating pH value to be less than 4 by nitric acid; preparing 300L of sodium phosphate solution with phosphate radical ion concentration of 2mol/L by deionized water, and regulating the pH value to be less than 4 by nitric acid;
sequentially adding a lithium salt aqueous solution, a ferrous salt aqueous solution and a phosphate aqueous solution into a 1000L reaction kettle, and uniformly stirring and mixing to obtain a mixed solution;
s2) slowly adding sodium hydroxide into the reaction kettle until the pH value is 6.5, heating to 120 ℃, keeping the reaction kettle sealed, keeping the pressure in the reaction kettle stable at 0.2MPa, keeping the temperature and the pressure for 3 hours, and finishing the reaction;
s3) filtering the reaction system to perform solid-liquid separation, washing the solid obtained by filtering with deionized water for at least three times, and drying to obtain a product C;
and S4) collecting the mother liquor and the washing liquid obtained by filtering in a stirring tank, adding phosphoric acid until the molar ratio of the phosphorus to the lithium in the stirring tank is slightly higher than 1:3, adding sodium hydroxide to adjust the PH to be 11.5, and then carrying out solid-liquid separation and drying to obtain the lithium phosphate.
Example 4
In this embodiment, lithium phosphate and ferrous sulfate are used as raw materials, and sulfuric acid and sodium hydroxide are used as acids and bases for adjusting the pH value to prepare a lithium iron phosphate precursor, and the specific preparation method is as follows:
s1) fully dissolving lithium phosphate by sulfuric acid, preparing 500L of solution with the lithium ion concentration of 3mol/L and the phosphate radical concentration of 1mol/L by deionized water, and adding sulfuric acid to adjust the pH value to be less than 4; preparing 500L of ferrous sulfate solution with ferrous ion concentration of 2mol/L by deionized water, and regulating pH value to be less than 4 by sulfuric acid;
sequentially adding a lithium phosphate solution and a ferrous salt solution into a 1000L reaction kettle, and uniformly stirring and mixing to obtain a mixed solution;
s2) slowly adding sodium hydroxide into the reaction kettle until the pH value is 6, heating to 110 ℃, keeping the reaction kettle sealed, keeping the pressure in the reaction kettle stable at 0.1MPa, and after the reaction is carried out for 5 hours under the condition of heat preservation and pressure maintaining, completing the reaction;
s3) filtering the reaction system to perform solid-liquid separation, washing the solid obtained by filtering with deionized water for at least three times, and drying to obtain a product D;
and S4) collecting the mother liquor and the washing liquid obtained by filtration in a stirring tank, adding phosphoric acid until the molar ratio of the phosphorus to the lithium in the stirring tank is slightly higher than 1:3, adding sodium hydroxide to adjust the PH to be 11, and then carrying out solid-liquid separation and drying to obtain the lithium phosphate.
Example 5
In this embodiment, lithium phosphate, lithium chloride, ferrous sulfate, ferrous chloride, monoammonium phosphate and sodium phosphate are used as raw materials, and sulfuric acid and sodium hydroxide are used as acids and bases for adjusting the pH value to prepare a lithium iron phosphate precursor, and the specific preparation method is as follows:
s1) fully dissolving lithium carbonate by sulfuric acid, then mixing lithium chloride, preparing 300L of solution with lithium ion concentration of 2mol/L by deionized water, and adding sulfuric acid to adjust the pH value to be less than 4; dissolving ferrous sulfate and ferrous chloride with deionized water, preparing 300L of ferrous solution with ferrous ion concentration of 1mol/L, and regulating pH value to be less than 4 with sulfuric acid; dissolving monoammonium phosphate and sodium phosphate by deionized water, preparing 300L of sodium phosphate solution with phosphate radical ion concentration of 1mol/L, and regulating pH value to be less than 4 by nitric acid;
sequentially adding a lithium phosphate solution and a ferrous salt solution into a 1000L reaction kettle, and uniformly stirring and mixing to obtain a mixed solution;
s2) slowly adding sodium hydroxide into the reaction kettle until the pH value is 6, heating to 105 ℃, keeping the reaction kettle sealed, keeping the pressure in the reaction kettle stable at 0.15MPa, keeping the temperature and the pressure for 4 hours, and finishing the reaction;
s3) filtering the reaction system to perform solid-liquid separation, washing the solid obtained by filtering with deionized water for at least three times, and drying to obtain a product E;
and S4) collecting the mother liquor and the washing liquid obtained by filtration in a stirring tank, adding phosphoric acid until the molar ratio of the phosphorus to the lithium in the stirring tank is slightly higher than 1:3, adding sodium hydroxide to adjust the PH to be 11, and then carrying out solid-liquid separation and drying to obtain the lithium phosphate.
Example 6
In this embodiment, lithium sulfate, ferrous sulfate and lithium dihydrogen phosphate are used as raw materials, and sulfuric acid and sodium hydroxide are used as acids and bases for adjusting the pH value to prepare a lithium iron phosphate precursor, and the specific preparation method is as follows:
s1) preparing 300L of lithium sulfate solution with the lithium ion concentration of 1mol/L by deionized water, and regulating the pH value to be less than 4 by sulfuric acid; preparing 300L of ferrous sulfate solution with ferrous ion concentration of 0.5mol/L by deionized water, and regulating the pH value to be less than 4 by sulfuric acid; preparing 300L of lithium dihydrogen phosphate solution with the phosphate radical ion concentration of 0.5mol/L by deionized water, and regulating the pH value to be less than 4 by sulfuric acid;
sequentially adding a lithium salt aqueous solution, a ferrous salt aqueous solution and a phosphate aqueous solution into a 1000L reaction kettle, and uniformly stirring and mixing to obtain a mixed solution;
s2) slowly adding sodium hydroxide solution into the reaction kettle until the pH value is 6.5, heating to 95 ℃, and keeping the reaction kettle in an unsealed state, so that the reaction kettle is kept at normal pressure, and after the reaction is carried out for 4.5 hours under the condition of heat preservation and pressure maintaining, completing the reaction;
s3) filtering the reaction system to perform solid-liquid separation, washing the solid obtained by filtering with deionized water for at least three times, and drying to obtain a product F;
and S4) collecting the mother solution and the washing solution obtained by filtering in a stirring tank, adding phosphoric acid until the molar ratio of the phosphorus to the lithium in the stirring tank is slightly higher than 1:3, adding sodium hydroxide solution to adjust the PH value to be 12, and then carrying out solid-liquid separation and drying to obtain the lithium phosphate.
Example 7
In this embodiment, lithium phosphate, lithium sulfate and ferrous sulfate are used as raw materials, and sulfuric acid and sodium hydroxide are used as acids and bases for adjusting the pH value to prepare a lithium iron phosphate precursor, and the specific preparation method is as follows:
s1) fully dissolving part of lithium phosphate by sulfuric acid, then mixing the lithium sulfate, preparing 300L of solution with the lithium ion concentration of 2mol/L by deionized water, and adding sulfuric acid to adjust the pH value to be less than 4; dissolving ferrous sulfate with deionized water, preparing 300L of ferrous sulfate solution with ferrous ion concentration of 1mol/L, and regulating pH value to be less than 4 with sulfuric acid; dissolving the rest lithium phosphate by deionized water, preparing 300L of lithium phosphate solution with phosphate radical ion concentration of 1mol/L, and regulating the pH value to be less than 4 by nitric acid;
sequentially adding a lithium phosphate solution and a ferrous salt solution into a 1000L reaction kettle, and uniformly stirring and mixing to obtain a mixed solution;
s2) slowly adding sodium hydroxide into the reaction kettle until the pH value is 6, heating to 105 ℃, keeping the reaction kettle sealed, keeping the pressure in the reaction kettle stable at 0.15MPa, keeping the temperature and the pressure for 4 hours, and finishing the reaction;
s3) filtering the reaction system to perform solid-liquid separation, washing the solid obtained by filtering with deionized water for at least three times, and drying to obtain a product G;
and S4) collecting the mother liquor and the washing liquid obtained by filtration in a stirring tank, adding phosphoric acid until the molar ratio of the phosphorus to the lithium in the stirring tank is slightly higher than 1:3, adding sodium hydroxide to adjust the PH to be 11, and then carrying out solid-liquid separation and drying to obtain the lithium phosphate.
The XRD pattern of the product A was measured by an X-ray diffractometer and the SEM pattern was measured by a scanning electron microscope, and the measured patterns are shown in FIG. 2 and FIG. 3. As can be seen from fig. 2, the product meets the lithium iron phosphate characteristics; as can be seen from fig. 3, the product obtained in example 1 has a regular hexagonal crystal structure and a uniform crystal size.
The products prepared in examples 1 to 7 were added with a carbon source and subjected to sanding, spray drying, sintering and grinding to prepare a carbon-coated lithium iron phosphate positive electrode material, which was used as a positive electrode material to prepare a button cell, and the initial discharge specific capacity, the initial charge capacity and the initial effect of 0.1C were measured, and the measurement results were as follows:
the preferred embodiments of the present application have been described in detail above, but the present application is not limited to the specific details of the above embodiments, and various simple modifications can be made to the technical solution of the present application within the scope of the technical concept of the present application, and all the simple modifications belong to the protection scope of the present application.
The foregoing description of the preferred embodiments of the application is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the application.
Claims (8)
1. The synthesis method for preparing the lithium iron phosphate precursor with high cost performance by controlling crystallization is characterized by comprising the following steps of:
s1) preparing a mixed solution of lithium salt, ferrous salt and phosphate; the pH of the mixed solution is less than 4;
s2) stirring the mixed solution obtained in the step S1) at room temperature, slowly adding alkali to adjust the pH value to 7, heating to 80 ℃, and keeping the reaction kettle in an unsealed state, so that the reaction kettle is kept at normal pressure, and after the reaction is carried out for 6 hours under the condition of heat preservation and pressure maintaining, completing the reaction;
s3) filtering to obtain solid precipitate, and washing and drying to obtain a lithium iron phosphate precursor;
in the S1), the mixed solution is prepared by the following method: preparing lithium salt water solution, ferrous salt water solution and phosphate salt water solution by deionized water respectively, adding acid to adjust the pH values of the lithium salt water solution, the ferrous salt water solution and the phosphate salt water solution to be less than 4 respectively, and stirring and mixing the lithium salt water solution, the ferrous salt water solution and the phosphate salt water solution uniformly to obtain a mixed solution of lithium salt, ferrous salt and phosphate;
in the S1), the concentration of ferrous ions in the mixed solution is 0.1-1 mol/L; the molar ratio of lithium ions, ferrous ions and phosphate ions is 1-3:1:1;
the crystal structure of the lithium iron phosphate precursor is a hexagonal crystal structure.
2. The method for synthesizing a lithium iron phosphate precursor according to claim 1, wherein the acid used for adjusting the lithium salt aqueous solution, the ferrous salt aqueous solution, and the phosphate aqueous solution is any one or more of sulfuric acid, hydrochloric acid, and nitric acid.
3. The method for synthesizing a lithium iron phosphate precursor with high cost performance according to claim 1, wherein in S1), the lithium salt is one or more of lithium sulfate, lithium chloride, lithium nitrate, lithium carbonate, and lithium phosphate.
4. The method for synthesizing a lithium iron phosphate precursor with high cost performance according to claim 1, wherein in S1), the ferrous salt is one or more of ferrous sulfate, ferrous chloride and ferrous nitrate.
5. The method for synthesizing a lithium iron phosphate precursor with high cost performance according to claim 1, wherein in S1), the phosphate is one or more of monoammonium phosphate, sodium phosphate, lithium phosphate, and lithium dihydrogen phosphate.
6. The method for synthesizing the lithium iron phosphate precursor with high cost performance by controlling crystallization according to claim 1, wherein in the step S2), the alkali is one or two of sodium hydroxide and ammonia water.
7. The method for synthesizing the lithium iron phosphate precursor with high cost performance by controlling crystallization according to any one of claims 1 to 6, wherein the method further comprises the step of S4) recovering residual lithium ions in a mother solution: and (3) adding phosphate or phosphoric acid into the filtrate obtained in the step (S3), adding alkali to adjust the pH value to 11-12, precipitating and separating lithium phosphate solid, and recovering lithium phosphate.
8. The method for synthesizing the lithium iron phosphate precursor with high cost performance by controlling crystallization according to claim 7, which is characterized in that: in the step S4), after phosphate or phosphoric acid is added, the mole ratio of phosphorus to lithium in the filtrate is not lower than 1:3.
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| CN101935029A (en) * | 2010-09-29 | 2011-01-05 | 彩虹集团公司 | Method for preparing lithium iron phosphate material |
| CN103400983A (en) * | 2013-07-29 | 2013-11-20 | 海门容汇通用锂业有限公司 | Method for synthesizing nano lithium iron phosphate without water of crystallization through atmospheric water phase |
| CN108539132A (en) * | 2018-01-26 | 2018-09-14 | 澳洋集团有限公司 | A kind of preparation method of zinc oxide-lithium iron phosphate composite anode material |
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