CN113054171A - Lithium iron phosphate material and method for preparing lithium iron phosphate material by using mixed iron source and mixed phosphorus source - Google Patents

Lithium iron phosphate material and method for preparing lithium iron phosphate material by using mixed iron source and mixed phosphorus source Download PDF

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CN113054171A
CN113054171A CN202110258116.5A CN202110258116A CN113054171A CN 113054171 A CN113054171 A CN 113054171A CN 202110258116 A CN202110258116 A CN 202110258116A CN 113054171 A CN113054171 A CN 113054171A
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iron phosphate
lithium iron
source
lithium
slurry
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杨吉
魏义华
江南
程光春
郝长旺
程正闯
孙杰
何中林
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Hubei RT Advanced Materials Co Ltd
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Hubei RT Advanced Materials Co Ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/5825—Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/624—Electric conductive fillers
    • H01M4/625—Carbon or graphite
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/628—Inhibitors, e.g. gassing inhibitors, corrosion inhibitors
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Abstract

The invention relates to the technical field of lithium ion battery material preparation, and discloses a lithium iron phosphate material and a method for preparing the lithium iron phosphate material by using a mixed iron source and a mixed phosphorus source. The method comprises the following steps: (1) adding an iron source and a phosphorus source into a dispersing agent according to the molar ratio of the iron element to the phosphorus element of 1:1-1.05, simultaneously adding a carbon source and an additive, and carrying out ball milling, wherein the iron source is iron phosphate and ferric oxide, and the phosphorus source is lithium phosphate and phosphoric acid; (2) sanding the ball-milling slurry until the solid content of the slurry is 30-45% and the granularity is 0.3-0.65 um; (3) performing spray drying on the sand-milled slurry to obtain a lithium iron phosphate precursor; (4) sintering the lithium iron phosphate precursor, and then cooling the precursor to room temperature by water, wherein the sintering temperature is 750-790 ℃, and the sintering time is 6-14 h; (5) the sintered material is crushed. The method can greatly reduce the production cost and enable the material to have excellent electrochemical performance.

Description

Lithium iron phosphate material and method for preparing lithium iron phosphate material by using mixed iron source and mixed phosphorus source
Technical Field
The invention relates to the technical field of lithium ion battery material preparation, in particular to a lithium iron phosphate material and a method for preparing the lithium iron phosphate material by using a mixed iron source and a mixed phosphorus source.
Background
Lithium iron phosphate is one of the mainstream anode materials of lithium ion batteries due to the advantages of large energy density, high voltage, good cycle performance, high safety performance and the like. With the continuous evolution of the lithium ion battery market, the requirements of finished automobile manufacturers and battery manufacturers on the comprehensive physicochemical performance of lithium iron phosphate are higher and higher; and meanwhile, the price of the lithium iron phosphate material is required to be reduced. How to manufacture the lithium iron phosphate material with excellent comprehensive performance by adopting lower manufacturing cost becomes the next breakthrough point of numerous lithium battery material manufacturers.
At present, the traditional lithium iron phosphate preparation process comprises a ferrous oxalate process, an iron oxide red process and an iron phosphate process. Wherein, the ferrous oxalate is used as an iron source and needs to be calcined by two steps, so the preparation period is long; the ferric oxide is used as an iron source to prepare the lithium iron phosphate, and the electrochemical performance of the lithium iron phosphate needs to be further improved; the lithium iron phosphate prepared by taking the iron phosphate as an iron source shows relatively superior physical and chemical properties and electrical properties, and becomes a mainstream preparation process of the lithium iron phosphate. However, the high manufacturing costs are also slowly limiting its application to a wider market. Meanwhile, lithium phosphate and phosphoric acid are used as phosphorus sources to replace the traditional raw materials of lithium carbonate, diammonium hydrogen phosphate and ammonium dihydrogen phosphate, so that the preparation cost of the material is further reduced.
Disclosure of Invention
The invention aims to overcome the problems that the cost for preparing the lithium iron phosphate material is higher and the application of the lithium iron phosphate material in wider markets is limited in the prior art, and provides a lithium iron phosphate material and a method for preparing the lithium iron phosphate material by using a mixed iron source and a mixed phosphorus source.
In order to achieve the above object, one aspect of the present invention provides a method for preparing a lithium iron phosphate material from a mixed iron source and a mixed phosphorus source, the method comprising the steps of:
(1) adding an iron source and a phosphorus source into a dispersing agent according to the molar ratio of the iron element to the phosphorus element of 1:1-1.05, simultaneously adding a carbon source and an additive, and performing ball milling to obtain ball milling slurry, wherein the iron source is iron phosphate and ferric oxide, the phosphorus source is lithium phosphate, phosphoric acid and iron phosphate, the carbon source is glucose and polyethylene glycol, and the additive is titanium dioxide;
(2) sanding the ball-milling slurry obtained in the step (1) until the solid content of the slurry is 30-45% and the granularity is 0.3-0.65um to obtain the sanding slurry;
(3) performing spray drying on the sand grinding slurry obtained in the step (2) to obtain a lithium iron phosphate precursor;
(4) sintering the lithium iron phosphate precursor obtained in the step (3) in an inert atmosphere, and then cooling the precursor to room temperature by water, wherein the sintering temperature is 750-;
(5) and (4) crushing the sintered material obtained in the step (4) to obtain a finished product of the lithium iron phosphate material.
Preferably, in the step (1), the addition amount of the carbon source is controlled so that the carbon content in the lithium iron phosphate material is 0.5 to 3 mass%.
Preferably, in the step (1), the addition amount of the additive is controlled so that the content of the doped metal cation in the lithium iron phosphate material is 0.02 to 0.3 mass%.
Preferably, in step (2), the ball-milled slurry is sand milled to a slurry solids content of 34-38% and a particle size of 0.45-0.65 um.
Preferably, in step (3), the spray drying conditions are: the feeding rate is 10-30Hz, the air inlet temperature is 200-240 ℃ and the air outlet temperature is 80-120 ℃.
More preferably, in step (3), the spray-drying conditions are: the feeding rate is 15-25Hz, the air inlet temperature is 210-230 ℃, and the air outlet temperature is 90-110 ℃.
Preferably, in the step (4), the inert atmosphere is at least one gas selected from nitrogen, argon and helium.
More preferably, in step (4), the gas used for the inert atmosphere is nitrogen.
Preferably, in step (5), the sintered material is pulverized to 1.0-2.5 um.
More preferably, in step (5), the sintered material is pulverized to 1.0-1.8 um.
In another aspect, the present invention provides a lithium iron phosphate material prepared by the method described above.
Compared with the prior art, the invention has the following beneficial effects:
1. the iron phosphate and the ferric oxide are adopted as the mixed iron source, so that the proportion of the iron phosphate as the iron source can be reduced, and the cost of the material is reduced; and the agglomeration of a single iron source can be prevented, so that the dispersibility of precursor particles is good, and the performance of the lithium iron phosphate material is favorably improved, and therefore, the disadvantage of preparing the lithium iron phosphate material by using the single iron source is greatly reduced.
2. Three mixed phosphorus sources of phosphoric acid, lithium phosphate and iron phosphate are adopted, and the phosphoric acid is used as the phosphorus source, so that the viscosity of the precursor slurry can be reduced, and the dispersibility and the uniformity of the slurry are improved; the lithium phosphate is used as a phosphorus source, and can provide a lithium source and a phosphorus source of the lithium iron phosphate at the same time, so that the utilization rate of raw materials is high; the ferric phosphate is used as a phosphorus source, can provide an iron source and the phosphorus source at the same time, and is a main raw material for synthesizing the lithium iron phosphate by the traditional method.
3. The adoption of two carbon sources, namely glucose and polyethylene glycol, can provide a perfect carbon coating effect, improve the conductivity of the carbon coating, and further improve the electrochemical performance; but also has the functions of dispersing and pore-forming, and prevents the agglomeration of the lithium iron phosphate material.
4. Titanium dioxide is used as an additive, and high-performance lithium iron phosphate with controllable and uniform components and small particle size can be obtained.
5. The lithium iron phosphate material is prepared by one-step sintering, the process is simple, the operation is convenient, the method is suitable for industrial production, and the prepared lithium iron phosphate material has better electrochemical performance.
Drawings
Fig. 1 is an SEM spectrum of lithium iron phosphate prepared in example 1.
Fig. 2 is an XRD spectrum of lithium iron phosphate prepared in example 2.
Fig. 3 is a charge-discharge curve for a button half cell of the sample prepared in example 1.
Fig. 4 is a charge and discharge curve for a button half cell of the sample prepared in example 2.
Fig. 5 is a charge-discharge curve for a button half cell of the sample prepared in example 3.
Fig. 6 is a charge and discharge curve for a button half cell of the sample prepared in example 4.
Fig. 7 is a charge-discharge curve for a button half cell of the sample prepared in example 5.
Detailed Description
The following detailed description of embodiments of the invention refers to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.
The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.
The invention provides a method for preparing a lithium iron phosphate material by using a mixed iron source and a mixed phosphorus source, which comprises the following steps:
(1) adding an iron source and a phosphorus source into a dispersing agent according to the molar ratio of the iron element to the phosphorus element of 1:1-1.05, simultaneously adding a carbon source and an additive, and performing ball milling to obtain ball milling slurry, wherein the iron source is iron phosphate and ferric oxide, the phosphorus source is lithium phosphate, phosphoric acid and iron phosphate, the carbon source is glucose and polyethylene glycol, and the additive is titanium dioxide;
(2) sanding the ball-milling slurry obtained in the step (1) until the solid content of the slurry is 30-45% and the granularity is 0.3-0.65um to obtain the sanding slurry;
(3) performing spray drying on the sand grinding slurry obtained in the step (2) to obtain a lithium iron phosphate precursor;
(4) sintering the lithium iron phosphate precursor obtained in the step (3) in an inert atmosphere, and then cooling the precursor to room temperature by water, wherein the sintering temperature is 750-;
(5) and (4) crushing the sintered material obtained in the step (4) to obtain a finished product of the lithium iron phosphate material.
In the method, the types of the iron source and the phosphorus source and the adding amount of the iron source and the phosphorus source are optimized, and particularly, phosphoric acid, lithium phosphate and iron phosphate are used as mixed phosphorus sources, so that the dispersibility and uniformity of the lithium iron phosphate can be improved, the manufacturing cost can be greatly saved, and the application market is widened. In addition, a specific carbon source and an additive are selected, the slurry is subjected to sand grinding to appropriate solid content and granularity, spray drying and sintering at appropriate temperature, and the performance of the prepared lithium iron phosphate material can be improved.
In particular embodiments, the iron source and the phosphorus source may be added to the dispersant in a molar ratio of iron to phosphorus of 1:1, 1:1.01, 1:1.02, 1:1.03, 1:1.04, or 1: 1.05. The iron element referred to herein means the sum of iron elements provided by iron phosphate and iron oxide, and the phosphorus element means the sum of phosphorus elements provided by lithium phosphate, phosphoric acid, and iron phosphate.
Further, in the step (1), the amount of the carbon source to be added may be controlled so that the carbon content in the lithium iron phosphate material is 0.5 to 3 mass%, and may be, for example, 0.5 mass%, 1 mass%, 1.2 mass%, 1.5 mass%, 2 mass%, 2.5 mass%, or 3 mass%.
In step (1), the carbon sources used are glucose and polyethylene glycol. The two carbon sources can provide a perfect carbon coating effect, improve the conductivity and further improve the electrochemical performance; but also has the functions of dispersing and pore-forming, and prevents the agglomeration of the lithium iron phosphate material.
In step (1), the additive used is titanium dioxide. Titanium dioxide is used as an additive, so that the high-performance lithium iron phosphate material with controllable and uniform components and small particle size can be obtained.
Further, in the step (1), the addition amount of the additive is controlled so that the content of the doped metal cations in the lithium iron phosphate material is 0.02 to 0.3 mass%. Specifically, the amount may be, for example, 0.02 mass%, 0.05 mass%, 0.1 mass%, 0.15 mass%, 0.2 mass%, 0.25 mass%, or 0.3 mass%.
In the method provided by the invention, in order to control the dispersion degree of the precursor and further improve the performance of the lithium iron phosphate material, the slurry needs to be sanded to a proper solid content and particle size.
In particular embodiments, the ball-milled slurry may be sanded to a solids content of 30%, 32%, 34%, 35%, 36%, 37%, 38%, 40%, 42%, or 45% of the slurry.
In particular embodiments, the ball milling slurry may be sanded to a particle size of 0.3um, 0.35um, 0.4um, 0.45um, 0.5um, 0.55um, 0.60um, or 0.65um for the slurry.
In a preferred embodiment, in step (2), the ball milled slurry may be sand milled to a solids content of 34-38% and a particle size of 0.45-0.65 um.
In the method of the present invention, in order to further improve the performance of the prepared lithium iron phosphate material, the conditions of spray drying and sintering should be reasonably controlled.
In the step (3), the feeding rate of the spray drying may be 10-30Hz, the inlet air temperature may be 200-240 ℃ and the outlet air temperature may be 80-120 ℃.
In particular embodiments, in step (3), the feed rate of the spray drying may be 10Hz, 12Hz, 14Hz, 16Hz, 18Hz, 20Hz, 22Hz, 24Hz, 26Hz, 28Hz or 30 Hz.
In specific embodiments, in step (3), the temperature of the inlet air for spray drying may be 200 ℃, 205 ℃, 210 ℃, 215 ℃, 220 ℃, 225 ℃, 230 ℃, 235 ℃ or 240 ℃.
In specific embodiments, the outlet air temperature of the spray drying may be 80 ℃, 85 ℃, 90 ℃, 95 ℃, 100 ℃, 105 ℃, 110 ℃, 115 ℃ or 120 ℃.
In a preferred embodiment, in step (3), the spray-drying conditions are: the feeding rate is 15-25Hz, the air inlet temperature is 210-230 ℃, and the air outlet temperature is 90-110 ℃.
In the method of the present invention, in the step (4), the sintering temperature may be 750 ℃, 755 ℃, 760 ℃, 765 ℃, 770 ℃, 775 ℃, 780 ℃, 785 ℃ or 790 ℃.
In the method of the present invention, in the step (4), the sintering time may be 6h, 7h, 8h, 9h, 10h, 11h, 12h, 13h, or 14 h.
In the method of the present invention, in the step (4), the inert gas may be at least one gas selected from the group consisting of nitrogen, argon and helium.
In a preferred embodiment, in step (4), the gas used for the inert atmosphere is nitrogen.
In order to improve the electrochemical performance of the prepared lithium iron phosphate material during use, the lithium iron phosphate material needs to be crushed to an appropriate particle size.
In the step (5), the sintered material may be pulverized to 1.0-2.5 um; specifically, for example, it may be 1um, 1.2um, 1.4um, 1.6um, 1.8um, 2um, 2.2um, 2.4um, or 2.5 um.
In a preferred embodiment, in step (5), the sintered material is pulverized to 1.0-1.8 um.
In a second aspect, the present invention provides a lithium iron phosphate material prepared by the method described above. The lithium iron phosphate material has good electrochemical performance and high compaction density.
The present invention will be described in detail by way of examples, but the scope of the present invention is not limited thereto.
Example 1
(1) Weighing 40kg of iron phosphate, 21.97kg of ferric oxide, 21.67kg of lithium phosphate, 10.73kg of phosphoric acid, 4.4kg of glucose, 4.8kg of polyethylene glycol and 0.16kg of titanium dioxide, adding the materials into a ball mill, and carrying out ball milling, wherein the molar ratio of iron elements to phosphorus elements is as follows: 1: 1.04;
(2) adding the slurry obtained in the step (1) into a sand mill, adding a proper amount of water, and adjusting the sand milling time until the solid content of the slurry is 34% and the granularity is 0.5 um;
(3) spray drying the slurry obtained in the step (2), and adjusting the feeding rate of spraying equipment to be 20Hz, the air inlet and outlet temperature to be 220 ℃ and the air outlet temperature to be 100 ℃ to obtain a lithium iron phosphate precursor;
(4) sintering the lithium iron phosphate precursor at 770 ℃ for 10h under the protection of nitrogen atmosphere, and cooling with water to room temperature to obtain a lithium iron phosphate sintered material;
(5) and crushing the lithium iron phosphate sintered material to 1.5um by using jet mill equipment to obtain the lithium iron phosphate material, wherein the carbon content in the lithium iron phosphate material is 1.2 mass%, and the content of the doped metal cations in the lithium iron phosphate material is 0.1 mass%.
Example 2
(1) Weighing 38kg of iron phosphate, 22.97kg of ferric oxide, 21.67kg of lithium phosphate, 11.85kg of phosphoric acid, 4.4kg of glucose, 2.4kg of polyethylene glycol and 0.24kg of titanium dioxide, adding the materials into a ball mill, and carrying out ball milling, wherein the molar ratio of iron elements to phosphorus elements is as follows: 1: 1.05;
(2) adding the slurry obtained in the step (1) into a sand mill, adding a proper amount of water, and adjusting the sand milling time, and then, sand milling until the solid content of the slurry is 36% and the granularity is 0.45 um;
(3) spray drying the slurry obtained in the step (2), and adjusting the feeding rate of a spraying device to be 15Hz, the air inlet and outlet temperature to be 230 ℃ and the air outlet temperature to be 110 ℃ to obtain a lithium iron phosphate precursor;
(4) sintering the lithium iron phosphate precursor for 14h at 760 ℃ under the protection of nitrogen atmosphere, and cooling the lithium iron phosphate precursor to room temperature by water to obtain a lithium iron phosphate sintered material;
(5) and (2) crushing the lithium iron phosphate sintered material to 1.8um by using jet mill equipment to obtain the lithium iron phosphate material, wherein the carbon content in the lithium iron phosphate material is 1 mass%, and the content of the doped metal cations in the lithium iron phosphate material is 0.15 mass%.
Example 3
(1) Weighing 40kg of iron phosphate, 21.97kg of ferric oxide, 21.67kg of lithium phosphate, 10.67kg of phosphoric acid, 6kg of glucose, 4.8kg of polyethylene glycol and 0.032kg of titanium dioxide, adding into a ball mill, and carrying out ball milling, wherein the molar ratio of iron elements to phosphorus elements is as follows: 1: 1.02;
(2) adding the slurry obtained in the step (1) into a sand mill, adding a proper amount of water, and adjusting the sand milling time, and then, sand milling until the solid content of the slurry is 38% and the granularity is 0.55 um;
(3) spray drying the slurry obtained in the step (2), and adjusting the feeding rate of a spraying device to be 25Hz, the air inlet and outlet temperature to be 210 ℃ and the air outlet temperature to be 100 ℃ to obtain a lithium iron phosphate precursor;
(4) sintering the lithium iron phosphate precursor at 775 ℃ for 8h under the protection of nitrogen atmosphere, and cooling to room temperature by water to obtain a lithium iron phosphate sintered material;
(5) and (2) crushing the lithium iron phosphate sintered material to 1.0um by using jet mill equipment to obtain the lithium iron phosphate material, wherein the carbon content in the lithium iron phosphate material is 1.5 mass%, and the content of the doped metal cations in the lithium iron phosphate material is 0.02 mass%.
Example 4
(1) Weighing 38kg of iron phosphate, 23.95kg of ferric oxide, 20.98kg of lithium phosphate, 12.68kg of phosphoric acid, 9.6kg of glucose, 2.4kg of polyethylene glycol and 0.1kg of titanium dioxide, adding into a ball mill, and carrying out ball milling, wherein the molar ratio of iron elements to phosphorus elements is as follows: 1: 1.03;
(2) adding the slurry obtained in the step (1) into a sand mill, adding a proper amount of water, and adjusting the sand milling time, and then, sand milling until the solid content of the slurry is 36% and the granularity is 0.65 um;
(3) spray drying the slurry obtained in the step (2), and adjusting the feeding rate of spraying equipment to be 20Hz, the air inlet and outlet temperature to be 220 ℃ and the air outlet temperature to be 90 ℃ to obtain a lithium iron phosphate precursor;
(4) sintering the lithium iron phosphate precursor at 780 ℃ for 10h under the protection of nitrogen atmosphere, and cooling the lithium iron phosphate precursor to room temperature by water to obtain a lithium iron phosphate sintered material;
(5) and (2) crushing the lithium iron phosphate sintered material to 1.2um by using jet mill equipment to obtain the lithium iron phosphate material, wherein the carbon content in the lithium iron phosphate material is 2 mass percent, and the content of the doped metal cations in the lithium iron phosphate material is 0.05 mass percent.
Example 5
(1) Weighing 40kg of iron phosphate, 21.97kg of ferric oxide, 21.67kg of lithium phosphate, 10.73kg of phosphoric acid, 2.2kg of glucose, 1.2kg of polyethylene glycol and 0.48kg of titanium dioxide, adding the materials into a ball mill, and carrying out ball milling, wherein the molar ratio of iron elements to phosphorus elements is as follows: 1: 1.04;
(2) adding the slurry obtained in the step (1) into a sand mill, adding a proper amount of water, and adjusting the sand milling time until the solid content of the slurry is 34% and the granularity is 0.5 um;
(3) spray drying the slurry obtained in the step (2), and adjusting the feeding rate of spraying equipment to be 20Hz, the air inlet and outlet temperature to be 220 ℃ and the air outlet temperature to be 100 ℃ to obtain a lithium iron phosphate precursor;
(4) sintering the lithium iron phosphate precursor at 770 ℃ for 10h under the protection of nitrogen atmosphere, and cooling with water to room temperature to obtain a lithium iron phosphate sintered material;
(5) and crushing the lithium iron phosphate sintered material to 1.5um by using jet mill equipment to obtain the lithium iron phosphate material, wherein the carbon content in the lithium iron phosphate material is 0.5 mass%, and the content of the doped metal cations in the lithium iron phosphate material is 0.3 mass%.
Comparative example 1
The procedure of example 1 was followed, except that phosphoric acid was not added in step (1). The specific operation is as follows:
(1) weighing 40kg of iron phosphate, 10.58kg of ferric oxide, 15.35kg of lithium phosphate, 4.4kg of glucose, 4.8kg of polyethylene glycol and 0.16kg of titanium dioxide, adding into a ball mill, and carrying out ball milling, wherein the molar ratio of iron element to phosphorus element is as follows: 1: 1.04;
(2) adding the slurry obtained in the step (1) into a sand mill, adding a proper amount of water, and adjusting the sand milling time until the solid content of the slurry is 34% and the granularity is 0.5 um;
(3) spray drying the slurry obtained in the step (2), and adjusting the feeding rate of spraying equipment to be 20Hz, the air inlet and outlet temperature to be 220 ℃ and the air outlet temperature to be 100 ℃ to obtain a lithium iron phosphate precursor;
(4) sintering the lithium iron phosphate precursor at 770 ℃ for 10h under the protection of nitrogen atmosphere, and cooling with water to room temperature to obtain a lithium iron phosphate sintered material;
(5) and crushing the lithium iron phosphate sintered material to 1.5um by using jet mill equipment to obtain the lithium iron phosphate material, wherein the carbon content in the lithium iron phosphate material is 1.2 mass%, and the content of the doped metal cations in the lithium iron phosphate material is 0.1 mass%.
Comparative example 2
The procedure of example 1 was followed except that the sintering temperature in step (4) was 800 ℃. The specific operation is as follows:
(1) weighing 40kg of iron phosphate, 21.97kg of ferric oxide, 21.67kg of lithium phosphate, 10.73kg of phosphoric acid, 4.4kg of glucose, 4.8kg of polyethylene glycol and 0.16kg of titanium dioxide, adding the materials into a ball mill, and carrying out ball milling, wherein the molar ratio of iron elements to phosphorus elements is as follows: 1: 1.04;
(2) adding the slurry obtained in the step (1) into a sand mill, adding a proper amount of water, and adjusting the sand milling time until the solid content of the slurry is 34% and the granularity is 0.5 um;
(3) spray drying the slurry obtained in the step (2), and adjusting the feeding rate of spraying equipment to be 20Hz, the air inlet and outlet temperature to be 220 ℃ and the air outlet temperature to be 100 ℃ to obtain a lithium iron phosphate precursor;
(4) sintering the lithium iron phosphate precursor at 800 ℃ for 10h under the protection of nitrogen atmosphere, and cooling the lithium iron phosphate precursor to room temperature by water to obtain a lithium iron phosphate sintered material;
(5) and crushing the lithium iron phosphate sintered material to 1.5um by using jet mill equipment to obtain the lithium iron phosphate material, wherein the carbon content in the lithium iron phosphate material is 1.0 mass percent, and the content of the doped metal cations in the lithium iron phosphate material is 0.1 mass percent.
Comparative example 3
The procedure is as in example 1, except that vanadium pentoxide is used as additive. The specific operation is as follows:
(1) weighing 40kg of iron phosphate, 21.97kg of ferric oxide, 21.67kg of lithium phosphate, 10.73kg of phosphoric acid, 4.4kg of glucose, 4.8kg of polyethylene glycol and 0.364kg of vanadium pentoxide, adding into a ball mill for ball milling, wherein the molar ratio of iron element to phosphorus element is as follows: 1: 1.04;
(2) adding the slurry obtained in the step (1) into a sand mill, adding a proper amount of water, and adjusting the sand milling time until the solid content of the slurry is 34% and the granularity is 0.5 um;
(3) spray drying the slurry obtained in the step (2), and adjusting the feeding rate of spraying equipment to be 20Hz, the air inlet and outlet temperature to be 220 ℃ and the air outlet temperature to be 100 ℃ to obtain a lithium iron phosphate precursor;
(4) sintering the lithium iron phosphate precursor at 770 ℃ for 10h under the protection of nitrogen atmosphere, and cooling with water to room temperature to obtain a lithium iron phosphate sintered material;
(5) and crushing the lithium iron phosphate sintered material to 1.5um by using jet mill equipment to obtain the lithium iron phosphate material, wherein the carbon content in the lithium iron phosphate material is 1.2 mass%, and the content of the doped metal cations in the lithium iron phosphate material is 0.1 mass%.
Comparative example 4
The procedure of example 1 was followed except that the slurry in step (2) was sanded to a particle size of 0.7 um. The specific operation is as follows:
(1) weighing 40kg of iron phosphate, 21.97kg of ferric oxide, 21.67kg of lithium phosphate, 10.73kg of phosphoric acid, 4.4kg of glucose, 4.8kg of polyethylene glycol and 0.16kg of titanium dioxide, adding the materials into a ball mill, and carrying out ball milling, wherein the molar ratio of iron elements to phosphorus elements is as follows: 1: 1.04;
(2) adding the slurry obtained in the step (1) into a sand mill, adding a proper amount of water, and adjusting the sand milling time until the solid content of the slurry is 34% and the granularity is 0.7 um;
(3) spray drying the slurry obtained in the step (2), and adjusting the feeding rate of spraying equipment to be 20Hz, the air inlet and outlet temperature to be 220 ℃ and the air outlet temperature to be 100 ℃ to obtain a lithium iron phosphate precursor;
(4) sintering the lithium iron phosphate precursor at 770 ℃ for 10h under the protection of nitrogen atmosphere, and cooling with water to room temperature to obtain a lithium iron phosphate sintered material;
(5) and crushing the lithium iron phosphate sintered material to 1.5um by using jet mill equipment to obtain the lithium iron phosphate material, wherein the carbon content in the lithium iron phosphate material is 1.2 mass%, and the content of the doped metal cations in the lithium iron phosphate material is 0.1 mass%.
Comparative example 5
The procedure of example 1 was followed, except that only glucose was used as the carbon source in step (1). The specific operation is as follows:
(1) weighing 40kg of iron phosphate, 21.97kg of ferric oxide, 21.67kg of lithium phosphate, 10.73kg of phosphoric acid, 6.4kg of glucose and 0.16kg of titanium dioxide, adding into a ball mill, and carrying out ball milling, wherein the molar ratio of iron element to phosphorus element is as follows: 1: 1.04;
(2) adding the slurry obtained in the step (1) into a sand mill, adding a proper amount of water, and adjusting the sand milling time until the solid content of the slurry is 34% and the granularity is 0.5 um;
(3) spray drying the slurry obtained in the step (2), and adjusting the feeding rate of spraying equipment to be 20Hz, the air inlet and outlet temperature to be 220 ℃ and the air outlet temperature to be 100 ℃ to obtain a lithium iron phosphate precursor;
(4) sintering the lithium iron phosphate precursor at 770 ℃ for 10h under the protection of nitrogen atmosphere, and cooling with water to room temperature to obtain a lithium iron phosphate sintered material;
(5) and crushing the lithium iron phosphate sintered material to 1.5um by using jet mill equipment to obtain the lithium iron phosphate material, wherein the carbon content in the lithium iron phosphate material is 1.2 mass%, and the content of the doped metal cations in the lithium iron phosphate material is 0.1 mass%.
Test example
Dispersing the lithium iron phosphate positive electrode materials prepared in the examples 1-5 and the comparative examples 1-5, Super-P and PVDF in NMP according to the mass ratio of 90:5:5, uniformly dispersing by ball milling, coating on aluminum foil, and drying in vacuum to obtain a positive electrode piece, wherein the electrolyte is 1mol/L LiPF6Wherein the volume ratio of the solvent is EC: DMC: EMC ═ 1:1:1 (volume ratio), and the diaphragm is Celgard polypropylene film and lithium metal sheet as negative electrode, and assembling them into a half-cell. The test voltage range is 2.5V-3.9V, the voltage is charged to 3.9V by a constant current and constant voltage charging mode, the voltage is discharged to 2.5V by a constant current discharging mode, the charging and discharging current is 0.2C, and the test results are shown in Table 1.
TABLE 1
Figure BDA0002968388720000131
Figure BDA0002968388720000141
The results in table 1 show that the lithium iron phosphate material prepared by the method of the present invention has high first charge and discharge capacity and compaction density after being prepared into a lithium ion battery, wherein the first charge specific capacity is more than 160mAh/g, the first discharge specific capacity is more than 153mAh/g, and the compaction density is 2.4g/cm3The above.
The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.

Claims (10)

1. A method for preparing a lithium iron phosphate material by using a mixed iron source and a mixed phosphorus source is characterized by comprising the following steps:
(1) adding an iron source and a phosphorus source into a dispersing agent according to the molar ratio of the iron element to the phosphorus element of 1:1-1.05, simultaneously adding a carbon source and an additive, and performing ball milling to obtain ball milling slurry, wherein the iron source is iron phosphate and ferric oxide, the phosphorus source is lithium phosphate, phosphoric acid and iron phosphate, the carbon source is glucose and polyethylene glycol, and the additive is titanium dioxide;
(2) sanding the ball-milling slurry obtained in the step (1) until the solid content of the slurry is 30-45% and the granularity is 0.3-0.65um to obtain the sanding slurry;
(3) performing spray drying on the sand grinding slurry obtained in the step (2) to obtain a lithium iron phosphate precursor;
(4) sintering the lithium iron phosphate precursor obtained in the step (3) in an inert atmosphere, and then cooling the precursor to room temperature by water, wherein the sintering temperature is 750-;
(5) and (4) crushing the sintered material obtained in the step (4) to obtain a finished product of the lithium iron phosphate material.
2. The method according to claim 1, wherein in step (1), the amount of the carbon source added is controlled so that the carbon content in the lithium iron phosphate material is 0.5 to 3 mass%.
3. The method according to claim 1 or 2, wherein in step (1), the additive is added in an amount controlled so that the content of the doped metal cation in the lithium iron phosphate material is 0.02 to 0.3 mass%.
4. The method of claim 1 or 2, wherein in step (2), the ball-milled slurry is sand milled to a slurry solids content of 34-38% and a particle size of 0.45-0.65 um.
5. The method according to claim 1, wherein in step (3), the spray-drying conditions are: the feeding rate is 10-30Hz, the air inlet temperature is 200-240 ℃ and the air outlet temperature is 80-120 ℃.
6. The method according to claim 5, wherein in step (3), the spray-drying conditions are: the feeding rate is 15-25Hz, the air inlet temperature is 210-230 ℃, and the air outlet temperature is 90-110 ℃.
7. The method according to claim 1, wherein in the step (4), the inert atmosphere is at least one gas selected from the group consisting of nitrogen, argon and helium;
preferably, in step (4), the gas used for the inert atmosphere is nitrogen.
8. The method according to claim 1, wherein in the step (5), the sintered material is pulverized to 1.0-2.5 um.
9. The method according to claim 8, wherein in the step (5), the sintered material is pulverized to 1.0-1.8 um.
10. A lithium iron phosphate material prepared by the method of any one of claims 1 to 9.
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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113735091A (en) * 2021-09-07 2021-12-03 湖北云翔聚能新能源科技有限公司 Preparation method of nano spherical lithium iron phosphate and lithium iron phosphate material
CN113929070A (en) * 2021-10-09 2022-01-14 湖北万润新能源科技股份有限公司 Preparation method of high-rate lithium iron phosphate cathode material
CN114261952A (en) * 2021-12-21 2022-04-01 蜂巢能源科技股份有限公司 Lithium iron phosphate anode material, preparation method and application thereof
CN114335478A (en) * 2021-12-31 2022-04-12 四川大学 Magnesium-doped lithium iron phosphate/carbon composite microsphere with high tap density as well as preparation method and application thereof
CN114933290A (en) * 2022-06-17 2022-08-23 德阳川发龙蟒新材料有限公司 Anhydrous ferric phosphate and ferric oxide mixture, synthesis method thereof, lithium iron phosphate, preparation method and application thereof
CN115385321A (en) * 2022-09-08 2022-11-25 锂源(深圳)科学研究有限公司 Flaky lithium iron phosphate positive electrode material and hydrothermal method preparation method thereof
CN115403020A (en) * 2022-09-07 2022-11-29 佛山市德方纳米科技有限公司 Preparation method of lithium iron phosphate material

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102556996A (en) * 2010-12-30 2012-07-11 中国电子科技集团公司第十八研究所 Preparation method for high-tap-density lithium iron phosphate
CN108550826A (en) * 2018-05-03 2018-09-18 沈阳国科金能新材料有限公司 A kind of preparation method and application of high-carbon content low specific surface area LiFePO4
CN109336079A (en) * 2018-11-20 2019-02-15 浙江瑞邦科技有限公司 A kind of preparation method of high-pressure solid LiFePO 4 material
CN111217347A (en) * 2018-11-23 2020-06-02 深圳市贝特瑞纳米科技有限公司 High-compaction lithium iron phosphate material and preparation method thereof
CN112390241A (en) * 2020-11-17 2021-02-23 湖北融通高科先进材料有限公司 Lithium iron phosphate material and method for preparing lithium iron phosphate material by taking mixed iron source and mixed lithium source as raw materials

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102556996A (en) * 2010-12-30 2012-07-11 中国电子科技集团公司第十八研究所 Preparation method for high-tap-density lithium iron phosphate
CN108550826A (en) * 2018-05-03 2018-09-18 沈阳国科金能新材料有限公司 A kind of preparation method and application of high-carbon content low specific surface area LiFePO4
CN109336079A (en) * 2018-11-20 2019-02-15 浙江瑞邦科技有限公司 A kind of preparation method of high-pressure solid LiFePO 4 material
CN111217347A (en) * 2018-11-23 2020-06-02 深圳市贝特瑞纳米科技有限公司 High-compaction lithium iron phosphate material and preparation method thereof
CN112390241A (en) * 2020-11-17 2021-02-23 湖北融通高科先进材料有限公司 Lithium iron phosphate material and method for preparing lithium iron phosphate material by taking mixed iron source and mixed lithium source as raw materials

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113735091A (en) * 2021-09-07 2021-12-03 湖北云翔聚能新能源科技有限公司 Preparation method of nano spherical lithium iron phosphate and lithium iron phosphate material
CN113929070A (en) * 2021-10-09 2022-01-14 湖北万润新能源科技股份有限公司 Preparation method of high-rate lithium iron phosphate cathode material
CN114261952A (en) * 2021-12-21 2022-04-01 蜂巢能源科技股份有限公司 Lithium iron phosphate anode material, preparation method and application thereof
CN114261952B (en) * 2021-12-21 2024-03-29 蜂巢能源科技股份有限公司 Lithium iron phosphate positive electrode material, preparation method and application thereof
CN114335478A (en) * 2021-12-31 2022-04-12 四川大学 Magnesium-doped lithium iron phosphate/carbon composite microsphere with high tap density as well as preparation method and application thereof
CN114933290A (en) * 2022-06-17 2022-08-23 德阳川发龙蟒新材料有限公司 Anhydrous ferric phosphate and ferric oxide mixture, synthesis method thereof, lithium iron phosphate, preparation method and application thereof
CN115403020A (en) * 2022-09-07 2022-11-29 佛山市德方纳米科技有限公司 Preparation method of lithium iron phosphate material
CN115403020B (en) * 2022-09-07 2024-03-12 佛山市德方纳米科技有限公司 Preparation method of lithium iron phosphate material
CN115385321A (en) * 2022-09-08 2022-11-25 锂源(深圳)科学研究有限公司 Flaky lithium iron phosphate positive electrode material and hydrothermal method preparation method thereof

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