CN116190612A - Boron-doped reduced graphene oxide coated lithium manganese iron phosphate composite material and preparation method thereof - Google Patents

Boron-doped reduced graphene oxide coated lithium manganese iron phosphate composite material and preparation method thereof Download PDF

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CN116190612A
CN116190612A CN202310242365.4A CN202310242365A CN116190612A CN 116190612 A CN116190612 A CN 116190612A CN 202310242365 A CN202310242365 A CN 202310242365A CN 116190612 A CN116190612 A CN 116190612A
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boron
graphene oxide
composite material
lithium
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陈涛
练平
王跃林
余锋磊
廖财斌
龙志林
王付
林桃
肖禹迪
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Hunan Yuneng New Energy Battery 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
    • H01M4/364—Composites as mixtures
    • 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
    • H01M4/366—Composites as layered products
    • 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
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • 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
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • 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
    • 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

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Abstract

The invention belongs to the field of synthesis and application of lithium ion battery anode materials, and particularly provides a boron-doped reduced graphene oxide coated lithium iron manganese phosphate composite material and a preparation method thereof, wherein the preparation method comprises the following steps: mixing a lithium source, an iron source, a manganese source, a phosphorus source, a boron source and an organic carbon source with water, grinding, adding graphene oxide, drying, calcining under nitrogen or inert gas atmosphere, and crushing. By compounding the boron doped reduced graphene oxide with lithium iron manganese phosphate, on one hand, the edge defect of the reduced graphene oxide can be increased by boron doping, and on the other hand, the characteristics of large specific surface area, strong conductivity, good flexibility and the like of the reduced graphene oxide can be fully utilized, so that lithium iron manganese phosphate particles are gathered from points to form a two-dimensional conductive network, and the conductivity of the composite material is enhanced.

Description

Boron-doped reduced graphene oxide coated lithium manganese iron phosphate composite material and preparation method thereof
Technical Field
The invention belongs to the field of synthesis and application of lithium ion battery anode materials, and particularly relates to a boron-doped reduced graphene oxide coated lithium iron manganese phosphate composite material and a preparation method thereof.
Background
Under the condition that the energy density of the lithium iron phosphate battery system is close to the theoretical extremum while the demand of the new energy automobile is rapidly increased and the price of raw materials is continuously increased, the desirability of novel anode materials with low cost and high energy density in the industry is further improved. The lithium iron manganese phosphate is definitely the lithium ion battery anode material which meets the related technical requirements at present.
The lithium iron manganese phosphate is used as an upgrade of the lithium iron phosphate, not only inherits the characteristics of low cost, high thermal stability, high safety and the like of the lithium iron phosphate, but also can make up the defect of low energy density of the lithium iron phosphate. Meanwhile, the lithium iron phosphate material and the battery production and the production equipment of the lithium iron phosphate have small fluctuation, the production line is not required to be rebuilt, the fluctuation cost is low, and the method accords with the economy. Although lithium iron manganese phosphate has many inherent advantages, there are still many defects to be improved at present, such as high powder resistance, low specific charge-discharge capacity and the like.
Disclosure of Invention
Therefore, the technical problem to be solved by the invention is to overcome the defects of high powder resistance and low charge-discharge specific capacity in the prior art, thereby providing the boron-doped reduced graphene oxide coated lithium iron manganese phosphate composite material with good composition and the preparation method thereof.
Therefore, the invention provides a preparation method of a boron-doped reduced graphene oxide coated lithium iron manganese phosphate composite material, which comprises the following steps:
mixing lithium source, iron source, manganese source, phosphorus source, boron source, organic carbon source and water, grinding to obtain mixed slurry with particle diameter D50 of 0.2-0.6 μm, adding graphene oxide, drying, calcining under nitrogen or inert gas atmosphere, and crushing.
Further, the mass of the boron element in the boron source accounts for 0.002-0.1wt% of the total mass of the lithium source, the iron source, the manganese source, the phosphorus source, the organic carbon source, the boron source and the graphene oxide, and is preferably 0.005-0.03wt%.
Further, the mass of the graphene oxide is 0.1 to 5wt%, preferably 0.4 to 0.8wt% of the total mass of the lithium source, the iron source, the manganese source, the phosphorus source, the organic carbon source, the boron source and the graphene oxide.
Further, the carbon element in the composite material accounts for 1-6%, preferably 1-3% of the total element of the composite material.
Further, the molar ratio of Li, mn, fe, P in the lithium source, the manganese source, the iron source and the phosphorus source is 0.9-1.1:0.5-0.7:0.3-0.5:0.9-1.1.
Further, the mass of the organic carbon source accounts for 1.5-4wt% of the total mass of the lithium source, the iron source, the manganese source, the phosphorus source, the organic carbon source, the boron source and the graphene oxide.
Further, the lithium source is at least one of lithium dihydrogen phosphate, lithium hydroxide, lithium carbonate, lithium phosphate or lithium acetate; and/or the iron source is at least one of ferrous oxalate, ferric phosphate, iron oxide red, ferric carbonate, ferrous nitrate, ferrous chloride and ferric hydroxide; and/or the manganese source is at least one of manganese sulfate, manganese carbonate, manganese dioxide, manganous oxide, manganese chloride and manganese nitrate; and/or the phosphorus source is at least one of lithium dihydrogen phosphate, lithium phosphate, ferric phosphate, monoammonium phosphate, diammonium phosphate or ammonium phosphate, and phosphoric acid; and/or the boron source is at least one of boric acid, trimethyl borate, boron oxide and tetraphenylboric acid; and/or the organic carbon source is at least one of citric acid, glucose, sucrose, polyethylene glycol, urea and polyacrylonitrile.
Further, the drying is spray drying.
Further, the calcination temperature is 400-1000 ℃, preferably 600-800 ℃, for 3-15 hours, preferably 5-10 hours.
Further, the particle size of the crushed material is 1-2 mu m.
The invention also provides the boron-doped reduced graphene oxide coated lithium manganese iron phosphate composite material prepared by the preparation method of any boron-doped reduced graphene oxide coated lithium manganese iron phosphate composite material.
The technical scheme of the invention has the following advantages:
1. according to the preparation method of the boron-doped reduced graphene oxide coated lithium iron manganese phosphate composite material, a lithium source, an iron source, a manganese source, a phosphorus source, an organic carbon source and a boron source are mixed with water and ground to obtain mixed slurry with the particle size D50 of 0.2-0.6 mu m, graphene oxide is added, and the mixed slurry is dried, and is calcined and crushed in the atmosphere of nitrogen or inert gas to prepare the composite material with the carbon content of 1-6%. According to the method, graphene oxide is calcined under nitrogen or inert gas atmosphere to form reduced graphene oxide, the reduced graphene oxide is fully compounded with lithium iron manganese phosphate mixed slurry with the particle size D50 of 0.2-0.6 mu m, so that lithium iron manganese phosphate particles are formed into a two-dimensional conductive network from point-to-point aggregation, the conductivity of the composite material can be enhanced, the pseudocapacitance characteristic of the reduced graphene oxide can be utilized to optimize the conductivity and provide specific capacitance, so that the electrochemical performance of lithium iron manganese phosphate is optimized multiple times, boron doping modification is introduced in the preparation, the characteristic of the reduced graphene oxide is further optimized, the crystallinity of lithium iron manganese phosphate is improved, the uniformity of mixing with various raw materials is ensured, the conductivity is further enhanced, the powder resistance is reduced, and the charge-discharge specific capacity is improved. The research shows that the particle size of the slurry is too large or too small to influence the powder resistance, and the particle size D50 is controlled to be 0.2-0.6 mu m, and graphene oxide is added after the slurry reaches the standard through grinding, so that the characteristic of large specific surface area of the slurry is maintained, the slurry is prevented from being excessively crushed, a two-dimensional conductive network is prevented from being damaged, the powder resistance is obviously reduced, and the specific charge capacity of charge and discharge is obviously improved. Too low a carbon content can reduce conductivity, affect electrochemical performance, and too high a carbon content can affect compaction density. According to the invention, the carbon content of the composite material is controlled to be 1-6%, so that the powder resistance is obviously reduced and the electrochemical performance is improved on the basis of considering that the compaction density meets the requirement.
2. According to the boron doped reduced graphene oxide coated lithium iron manganese phosphate composite material and the preparation method thereof, the doping of boron element is controlled to be 0.002-0.1wt%, and in certain preferred embodiments, the physicochemical property of the composite material can be further optimized by controlling the doping of boron element to be 0.005-0.03wt%, because the doping of boron element can increase the edge defect of reduced graphene oxide, the conductivity is further enhanced, meanwhile, boron has a certain fluxing effect in the process of generating lithium iron manganese phosphate crystals, the crystallinity of the material is enhanced, and the effect of promoting the compaction density of material powder is improved to a certain extent.
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In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the present invention, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.
FIG. 1 is an SEM image of the material obtained in example 1 of the present invention;
FIG. 2 is a charge-discharge curve of the material obtained in example 1 of the present invention.
Detailed Description
The following examples are provided for a better understanding of the present invention and are not limited to the preferred embodiments described herein, but are not intended to limit the scope of the invention, any product which is the same or similar to the present invention, whether in light of the present teachings or in combination with other prior art features, falls within the scope of the present invention.
The specific experimental procedures or conditions are not noted in the examples and may be followed by the operations or conditions of conventional experimental procedures described in the literature in this field. The reagents or apparatus used were conventional reagent products commercially available without the manufacturer's knowledge.
Example 1
The embodiment provides a preparation method of a boron-doped reduced graphene oxide coated lithium iron manganese phosphate composite material, which comprises the following steps:
firstly, 5741.4ml of deionized water is taken and added into a premixing tank, and then LiMn is adopted 0.6 Fe 0.4 PO 4 Weighing manganese carbonate, ferric phosphate, lithium carbonate, 1138.5g, 1000g, 610.5g and 970.2g of phosphoric acid respectively according to the molar ratio, gradually adding into a premixing tank to obtain a premix, adding 3.156g of boric acid and 77.2g of glucose, stirring for 1h at 20 ℃ to obtain a mixed slurry, transferring the mixed slurry into a sand mill to grind until the particle size D50 reaches 0.4 mu m, adding 26.3g of graphene oxide, grinding, performing spray drying treatment on the precursor slurry which is uniformly mixed, and then placing into a box furnace filled with nitrogen to perform heat treatment for 9h at 750 ℃ to obtain boron doped reduced graphene oxide coated lithium manganese iron phosphate (B-rGO/LiMn) 0.6 Fe 0.4 PO 4 ) The composite material is finally crushed into powder with D50 of about 1 mu m.
Fig. 1 is an SEM image of the material obtained in this example, and it can be seen from the image that lithium iron manganese phosphate particles are uniformly distributed, and a thin layer of "light yarn" shaped reduced graphene oxide is covered on the surface, which indicates that the material has good degree of compositing. Fig. 2 is a charge-discharge curve of the material obtained in this example at a current of 0.1C, and it can be found that the curve completely combines the charge-discharge characteristics of lithium iron manganese phosphate.
Example 2
The embodiment provides a preparation method of a boron-doped reduced graphene oxide coated lithium iron manganese phosphate composite material, which is basically the same as embodiment 1, and differs only in that: the amount of graphene oxide used was 52.6g.
Example 3
The embodiment provides a preparation method of a boron-doped reduced graphene oxide coated lithium iron manganese phosphate composite material, which is basically the same as embodiment 1, and differs only in that: the amount of graphene oxide used was 131.5g.
Example 4
Firstly, 5741.4ml of deionized water is taken and added into a premixing tank, and then LiMn is adopted 0.6 Fe 0.4 PO 4 Weighing manganese tetraoxide, ferric phosphate, lithium hydroxide, 755.7g, 1000g, 396g and 970.2g of phosphoric acid according to the molar ratio of the elements, gradually adding into a premixing tank to obtain a premix, adding 1.778g of boron oxide and 155g of polyethylene glycol, stirring at 20 ℃ for 1h to obtain a solid-liquid mixture, transferring the solid-liquid mixture into a sand mill to grind until the particle size D50 reaches 0.4 mu m, adding 26.3g of graphene oxide, grinding for several circles, performing spray drying treatment on the precursor slurry which is uniformly mixed, and then placing the precursor slurry into a box-type furnace filled with nitrogen to perform heat treatment at 800 ℃ for 10h to obtain boron-doped reduced graphene oxide coated lithium manganese iron phosphate (B-rGO/LiMn) 0.6 Fe 0.4 PO 4 ) The composite material is finally crushed into powder with D50 of about 1 mu m.
Comparative example 1
The comparative example provides a preparation method of a boron-doped reduced graphene oxide coated lithium iron manganese phosphate composite material, which is basically the same as that of example 1, and differs only in that: the dosage of glucose is 231.6g, and boric acid and graphene oxide are not added.
Comparative example 2
The comparative example provides a preparation method of a boron-doped reduced graphene oxide coated lithium iron manganese phosphate composite material, which is basically the same as that of example 1, and differs only in that: the dosage of glucose is 77.2g, the dosage of graphene oxide is 26.3g, and boric acid is not added.
Comparative example 3
The comparative example provides a preparation method of a boron-doped reduced graphene oxide coated lithium iron manganese phosphate composite material, which is basically the same as that of example 1, and differs only in that: the dosage of glucose is 231.6g, the dosage of boric acid is 3.156g, and no graphene oxide is added.
Comparative example 4
The comparative example provides a preparation method of a boron-doped reduced graphene oxide coated lithium iron manganese phosphate composite material, which is basically the same as that of example 1, and differs only in that: the dosage of glucose is 77.2g, the dosage of boric acid is 3.156g, and the dosage of graphene oxide is 13.15g.
Comparative example 5
The comparative example provides a preparation method of a boron-doped reduced graphene oxide coated lithium iron manganese phosphate composite material, which is basically the same as example 1, except that the particle sizes of the mixed slurries are different: in this comparative example, the mixed slurry was milled in a sand mill to a particle size D50 of 0.1 μm, then 26.3g of graphene oxide was added, and after milling, the uniformly mixed precursor slurry was spray-dried, and then placed in a nitrogen-filled box furnace and heat-treated at 750 ℃ for 9 hours to obtain boron-doped reduced graphene oxide-coated lithium iron manganese phosphate (B-rGO/LiMn) 0.6 Fe 0.4 PO 4 ) The composite material is finally crushed into powder with D50 of about 1 μm.
Comparative example 6
The comparative example provides a preparation method of a boron-doped reduced graphene oxide coated lithium iron manganese phosphate composite material, which is basically the same as example 1, except that the particle sizes of the mixed slurries are different: in this comparative example, the mixed slurry was milled in a sand mill to a particle size D50 of 1 μm, then 26.3g of graphene oxide was added, and after milling, the uniformly mixed precursor slurry was spray-dried, and then placed in a nitrogen-filled box furnace and heat-treated at 750 ℃ for 9 hours to obtain boron-doped reduced graphene oxide-coated lithium manganese iron phosphate (B-rGO/LiMn) 0.6 Fe 0.4 PO 4 ) The composite material is finally crushed into powder with D50 of about 1 μm.
Comparative example 7
The comparative example provides a preparation method of a boron-doped reduced graphene oxide coated lithium iron manganese phosphate composite material, which is basically the same as example 1, except that the particle sizes of the mixed slurries are different: the mixed slurry of the comparative example is directly added with 26.3g of graphene oxide without grinding, the precursor slurry which is uniformly mixed is directly subjected to spray drying treatment, and then is placed in a box-type furnace filled with nitrogen for heat treatment for 9 hours at 750 ℃ to obtain the boron doped reduced graphene oxide coatingLithium iron manganese phosphate (B-rGO/LiMn) 0.6 Fe 0.4 PO 4 ) The composite material is crushed into powder with D50 of about 1 μm.
Experimental example
The composite materials prepared in each example and comparative example were subjected to physical and electrochemical performance testing, wherein the carbon content was the percentage of carbon element in the total element of the composite material, and the composite materials were tested using an infrared carbon-sulfur analyzer. The compacted density is the mass per unit volume of the material and is measured using a compacted density tester. Powder resistance was tested using a powder resistivity tester.
The batteries were assembled using the composite materials prepared in each of the examples and comparative examples as follows: mixing the conforming material, conductive carbon black and polyvinylidene fluoride (PVDF) as an adhesive according to the mass ratio of 90:5:5, using N-methyl pyrrolidone (NMP) as a solvent, preparing slurry, uniformly coating the slurry on aluminum foil, drying, compacting, and vacuum-drying at 120 ℃ for 12 hours to obtain a positive plate, wherein the mass of active substances of the positive plate is 12mg. The negative electrode adopts a metal lithium sheet, the diaphragm is a polypropylene porous membrane, and NaPF6/EC+DEC+DMC (EC: DEC: DMC=1:1:1 volume ratio) of electrolyte lmol/L. The method for calculating the 0.1C efficiency under the condition of 0.1C and the voltage range of 2.0V-4.3V is used for testing the specific charge-discharge capacity: 0.1C efficiency (%) = 0.1C specific discharge capacity (mAh/g)/0.1C specific charge capacity (mAh/g) ×100%; the results are shown in the following table.
Figure BDA0004124734000000081
As can be seen from the above table, all carbon sources of comparative example 1 were from glucose and no boron doped carbon coated composites, comparative example 2 was a reduced graphene oxide composite without boron doping, and comparative example 3 was a boron doped carbon coated composite with all glucose as carbon source. Comparison of comparative examples 1-3 with the present example 1 shows that under the condition of similar carbon content, the boron doped reduced graphene oxide coated lithium iron manganese phosphate composite material provided in examples 1-4 of the present application, and the carbon source comes from the organic carbon source and the graphene oxide powder at the same time, the resistance is obviously reduced, and the specific discharge capacity and efficiency are obviously improved. Comparative example 4 although a boron-doped reduced graphene oxide-coated lithium manganese iron phosphate composite material was provided, the carbon content was relatively small due to the reduced amount of graphene oxide, the powder resistance of the composite material was not lowered, and the electrochemical performance effect was also relatively poor.
Comparative example 5 the D50 particle size of the mixed slurry before graphene oxide was added was controlled to 0.1 μm, and too small particle size also increased the primary particle agglomeration, so the powder resistance was large and the electrochemical performance was also reduced. Comparative example 6 the D50 particle size of the mixed slurry before graphene oxide addition was 1 μm, large particles were too large, the ion transport distance was prolonged, the polarization of the material was exacerbated, and the electrochemical performance of the composite material was also not optimistic. The material of comparative example 7 was not ground, resulting in a final product with very large particle size, large powder resistance and poor electrochemical properties. Examples 1 to 4 as compared with comparative examples 5 to 7, examples 1 to 4 according to the present invention significantly reduced the powder resistance and improved the electrochemical performance by controlling the particle size of the mixed slurry within a proper range by grinding.
In comparison with examples 1 to 3, example 1 can further improve the compacted density while giving consideration to the electrochemical properties by controlling the carbon content within a preferable range.
It is apparent that the above examples are given by way of illustration only and are not limiting of the embodiments. Other variations or modifications of the above teachings will be apparent to those of ordinary skill in the art. It is not necessary here nor is it exhaustive of all embodiments. While still being apparent from variations or modifications that may be made by those skilled in the art are within the scope of the invention.

Claims (10)

1. The preparation method of the boron-doped reduced graphene oxide coated lithium iron manganese phosphate composite material is characterized by comprising the following steps of:
mixing a lithium source, an iron source, a manganese source, a phosphorus source, an organic carbon source and a boron source with water, grinding to obtain mixed slurry with the particle size D50 of 0.2-0.6 mu m, adding graphene oxide, drying, calcining and crushing under the atmosphere of nitrogen or inert gas to prepare the composite material with the carbon content of 1-6%.
2. The method for preparing the boron-doped reduced graphene oxide coated lithium iron manganese phosphate composite material according to claim 1, wherein the mass of boron element in the boron source accounts for 0.002-0.1wt%, preferably 0.005-0.03wt% of the total mass of the lithium source, the iron source, the manganese source, the phosphorus source, the organic carbon source, the boron source and the graphene oxide.
3. The method for preparing the boron-doped reduced graphene oxide coated lithium iron manganese phosphate composite material according to claim 1 or 2, wherein the mass of the graphene oxide accounts for 0.1-5wt%, preferably 0.4-0.8wt% of the total mass of the lithium source, the iron source, the manganese source, the phosphorus source, the organic carbon source, the boron source and the graphene oxide.
4. The method for preparing a boron-doped reduced graphene oxide-coated lithium iron manganese phosphate composite material according to any one of claims 1 to 3, wherein the carbon content of the composite material is 1 to 3%.
5. The preparation method of the boron-doped reduced graphene oxide coated lithium iron manganese phosphate composite material according to claim 1, wherein the molar ratio of Li, mn, fe, P in a lithium source, a manganese source, an iron source and a phosphorus source is 0.9-1.1:0.5-0.7:0.3-0.5:0.9-1.1.
6. The method for preparing a boron-doped reduced graphene oxide coated lithium iron manganese phosphate composite material according to any one of claims 1 to 4, wherein the lithium source is at least one of lithium dihydrogen phosphate, lithium hydroxide, lithium carbonate, lithium phosphate or lithium acetate; and/or the iron source is at least one of ferrous oxalate, ferric phosphate, iron oxide red, ferric carbonate, ferrous nitrate, ferrous chloride and ferric hydroxide; and/or the manganese source is at least one of manganese sulfate, manganese carbonate, manganese dioxide, manganous oxide, manganese chloride and manganese nitrate; and/or the phosphorus source is at least one of lithium dihydrogen phosphate, lithium phosphate, ferric phosphate, ammonium dihydrogen phosphate, diammonium hydrogen phosphate, ammonium phosphate and phosphoric acid; and/or the boron source is at least one of boric acid, trimethyl borate, boron oxide and tetraphenylboric acid; and/or the organic carbon source is at least one of citric acid, glucose, sucrose, polyethylene glycol, urea and polyacrylonitrile.
7. The method for preparing a boron-doped reduced graphene oxide coated lithium iron manganese phosphate composite material according to any one of claims 1 to 6, wherein the drying is spray drying.
8. The method for preparing a boron-doped reduced graphene oxide coated lithium iron manganese phosphate composite material according to any one of claims 1 to 7, wherein the calcination temperature is 400 to 1000 ℃, preferably 600 to 800 ℃, for 3 to 15 hours, preferably 5 to 10 hours.
9. The method for preparing the boron-doped reduced graphene oxide coated lithium iron manganese phosphate composite material according to any one of claims 1 to 8, wherein the particle size of the crushed material is 1 to 2 μm.
10. The boron-doped reduced graphene oxide coated lithium iron manganese phosphate composite material prepared by the preparation method of the boron-doped reduced graphene oxide coated lithium iron manganese phosphate composite material of any one of claims 1 to 9.
CN202310242365.4A 2023-03-13 2023-03-13 Boron-doped reduced graphene oxide coated lithium manganese iron phosphate composite material and preparation method thereof Pending CN116190612A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117720086A (en) * 2024-02-07 2024-03-19 湖南裕能新能源电池材料股份有限公司 Lithium iron manganese phosphate base material, positive electrode material, preparation method of positive electrode material and lithium battery

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117720086A (en) * 2024-02-07 2024-03-19 湖南裕能新能源电池材料股份有限公司 Lithium iron manganese phosphate base material, positive electrode material, preparation method of positive electrode material and lithium battery
CN117720086B (en) * 2024-02-07 2024-05-14 湖南裕能新能源电池材料股份有限公司 Lithium iron manganese phosphate base material, positive electrode material, preparation method of positive electrode material and lithium battery

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