CN114864896A - In-situ carbon-coated nano lithium iron phosphate cathode material and preparation method thereof - Google Patents

In-situ carbon-coated nano lithium iron phosphate cathode material and preparation method thereof Download PDF

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CN114864896A
CN114864896A CN202210499014.7A CN202210499014A CN114864896A CN 114864896 A CN114864896 A CN 114864896A CN 202210499014 A CN202210499014 A CN 202210499014A CN 114864896 A CN114864896 A CN 114864896A
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iron phosphate
lithium iron
situ carbon
coated nano
nano lithium
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徐艳
侯晓刚
施本义
谢小明
陈玉娴
王佳蕊
王卫军
施辉
曾能
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Lanzhou Lanshi Zhongke Nano Technology Co ltd
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Abstract

The invention provides a preparation method of an in-situ carbon-coated nano lithium iron phosphate anode material, which comprises the steps of obtaining a nano lithium iron phosphate precursor with good dispersibility under the action of a surfactant through a multiphase interface reactor; aging the lithium iron phosphate precursor slurry, and carrying out solvothermal reaction under the protection of inert gas to obtain a lithium iron phosphate slurry; performing solid-liquid separation on the lithium iron phosphate slurry, washing to obtain a lithium iron phosphate filter cake, and drying the filter cake in a vacuum oven to obtain nano lithium iron phosphate; and (3) placing the nano lithium iron phosphate into a tube furnace, preserving the heat for several hours at a certain temperature, and roasting to obtain the in-situ carbon-coated nano lithium iron phosphate. The nano lithium iron phosphate prepared by the method has uniform particle size distribution and smaller particle size, shortens the diffusion path of lithium ions, and has better rate capability, lithium storage performance and the like.

Description

In-situ carbon-coated nano lithium iron phosphate cathode material and preparation method thereof
Technical Field
The invention belongs to the technical field of lithium ion batteries, and relates to an in-situ carbon-coated nano lithium iron phosphate cathode material and a preparation method thereof.
Background
With the continuous development of global economy, the energy crisis is gradually deepened, the environmental awareness is gradually enhanced, the environment-friendly low-carbon power battery industry is rapidly developed, and the lithium ion battery becomes one of the mainstream development directions of the power battery by virtue of excellent performance and moderate manufacturing cost of the lithium ion battery. Among various lithium ion battery anode materials, lithium iron phosphate has the advantages of higher safety stability, longer cycle life, relatively lower cost and environmental friendliness, thereby becoming the most promising anode material for low-cost lithium ion batteries. The high-temperature solid phase method is the most traditional preparation method in the lithium iron phosphate synthesis process, but the reaction process of the method is difficult to control, the product has large particle size, is easy to agglomerate, has irregular appearance and has poor batch consistency. Compared with a high-temperature solid phase method, the lithium iron phosphate synthesized by the hydrothermal method has controllable shape, good uniformity and relatively small particle size, and is beneficial to the improvement of the electrochemical performance of the lithium iron phosphate. Chinese patent CN103400984 discloses a hydrothermal synthesis method for preparing lithium iron phosphate cathode material with controllable lattice development, which obtains lithium iron phosphate with high crystallinity and small particle size by controlling the temperature rising and reducing rate of hydrothermal reaction. In the method, the mixing of the raw materials in the previous stage is carried out step by step, the uniformity of a hydrothermal precursor of the lithium iron phosphate cannot be guaranteed, the generation of subsequent lithium iron phosphate is influenced, the particle size of the lithium iron phosphate prepared by the method is about 0.5 mu m, the lithium iron phosphate is flaky, the particle size is large, the lithium ion diffusion is not facilitated, and meanwhile, the lithium storage capacity of the flaky lithium iron phosphate is reduced.
Disclosure of Invention
The invention aims to provide a preparation method of in-situ carbon-coated nano lithium iron phosphate, which solves the technical problems of low lithium ion diffusion rate, poor electronic conductivity, poor rate performance, low lithium storage capacity and the like of a lithium iron phosphate cathode material in the prior art.
In order to solve the technical problems, the invention adopts the technical scheme that:
a preparation method of an in-situ carbon-coated nano lithium iron phosphate cathode material specifically comprises the following steps:
s1, preparing an iron source solution, a lithium source solution, a phosphorus source solution and a surfactant solution with certain concentration, and continuously conveying the solutions in parallel flow to a multi-phase interface reactor for precipitation reaction, wherein the molar ratio of lithium to iron to phosphorus is Li: fe: p =2-3.5:1:1-1.5, the amount of the surfactant is 0.05-0.5% of the amount of the iron source substance, the concentration of the iron source is 0.1-1 mol/L, under the protection of inert gas, the reaction temperature is 5-80 ℃, the pH value is 6-10, the stirring speed is 3000-5000rpm, the solution flow is 50-300mL/min, and blue gray lithium iron phosphate precursor slurry is obtained through reaction;
s2, aging the lithium iron phosphate precursor slurry for 0.5-4 hours, then adding part of the slurry into a stainless steel reaction kettle, adding a certain amount of solvent, and carrying out solvothermal reaction at the temperature of 300 ℃ for 2-6 hours under the protection of inert gas at a certain stirring speed to obtain lithium iron phosphate slurry;
s3, performing solid-liquid separation on the lithium iron phosphate slurry, alternately washing the slurry with ethanol and water for multiple times, and drying the washed lithium iron phosphate filter cake in a vacuum oven to obtain nano lithium iron phosphate;
and S4, placing the nano lithium iron phosphate into a tubular furnace, preserving the heat for several hours at a certain temperature, and roasting to obtain the in-situ carbon-coated nano lithium iron phosphate.
Preferably, in S1, the iron source is one or more of ferrous salt, ferrous sulfate, ferrous oxalate, ferrous acetate or ferrous ammonium sulfate.
Preferably, in S1, the lithium source is one or a combination of two of lithium hydroxide and lithium carbonate.
Preferably, in S1, the phosphorus source is one or more of phosphoric acid, diammonium hydrogen phosphate, ammonium dihydrogen phosphate and sodium phosphate.
Preferably, in S1, the surfactant is one or more of polyethylene glycol, polyvinylpyrrolidone, polyvinyl alcohol, sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, and cetyltrimethylammonium bromide.
Preferably, in S1, the inert gas is nitrogen.
Preferably, in S2, the solvent is one or a combination of two of water and N-methyl-2-pyrrolidone.
Preferably, in S2, the ratio of the volume of the solvent to the volume of the slurry is 1-2.5: 1.
Preferably, in S2, the stirring speed is 150-300 rpm.
Preferably, in S2, the inert gas is at least one of nitrogen or argon.
Preferably, in S3, the drying temperature is 50-80 ℃ and the drying time is 8-24 hours.
Preferably, in S4, the roasting temperature is 650-750 ℃ and the roasting time is 4-6 hours.
Preferably, in S4, the atmosphere is at least one of nitrogen, argon, or hydrogen.
Compared with the prior art, the invention has the beneficial effects that:
1. the invention adopts a multi-phase interface reactor,under the action of a surfactant, a nano-scale lithium iron phosphate precursor with good dispersibility can be obtained; the nanometer lithium iron phosphate precursor is a molecular-scale homogeneous mixture of nanometer lithium phosphate and nanometer ferrous phosphate, and the lithium phosphate and the ferrous phosphate react to generate the lithium iron phosphate, the difficulty and Li of the lithium iron phosphate + And Fe 2+ The diffusion rate in the solid phase is in positive correlation, and the nano lithium phosphate and the nano ferrous phosphate obtained in the invention have smaller particle size and are uniformly mixed, thereby being beneficial to the generation of nano lithium iron phosphate; the nano lithium iron phosphate prepared by the method has uniform particle size distribution and smaller particle size, shortens the diffusion path of lithium ions, and ensures that the nano lithium iron phosphate has better rate capability, lithium storage performance and the like.
2. In the invention, in the roasting process of the nano lithium iron phosphate, the surfactant is pyrolyzed and carbonized to form carbon-coated lithium iron phosphate, the conductivity of the nano lithium iron phosphate is improved, the rate capability is further optimized, and the specific capacity is improved.
Drawings
FIG. 1 is an XRD pattern of a precursor powder prepared in example 1 of the present invention;
FIG. 2 is an SEM image of a precursor powder prepared in example 1 of the present invention;
FIG. 3 is an XRD pattern of in-situ carbon-coated nano lithium iron phosphate prepared in example 1 of the present invention;
FIG. 4 is an SEM image of in-situ carbon-coated nano-lithium iron phosphate prepared in example 1 of the present invention;
fig. 5 is a charge-discharge diagram of in-situ carbon-coated nano lithium iron phosphate prepared in embodiment 1 under 0.1C.
Detailed Description
The invention will be further explained and illustrated with reference to specific examples; it should be noted that the following examples are not intended to limit the scope of the claimed invention.
Example 1
A preparation method of an in-situ carbon-coated nano lithium iron phosphate cathode material specifically comprises the following steps:
s1, preparing 0.15 mol/L ferrous sulfate solution, adding 1.35g of polyethylene glycol-6000, preparing 0.2 mol/L phosphoric acid solution, preparing 0.3mol/L lithium hydroxide solution, adding 1.3g of sodium dodecyl sulfate, continuously conveying the three solutions in a parallel flow manner to a multiphase interface reactor for precipitation reaction, and reacting under the protection of nitrogen to obtain blue gray lithium iron phosphate precursor slurry. Wherein the reaction temperature is room temperature, the stirring speed is 3000rpm, and the solution flow is 200 mL/min.
S2, aging the lithium iron phosphate precursor slurry obtained in the step S1 for 2 hours, adding 80ml of the lithium iron phosphate precursor slurry into a 500ml stainless steel reaction kettle, adding 160ml of N-methyl pyrrolidone, setting the stirring speed to be 200rpm, the heat preservation temperature to be 180 ℃, and the heat preservation time to be 5 hours, and carrying out solvothermal reaction under the protection of nitrogen to obtain the lithium iron phosphate slurry; the reaction principle of the process is
Figure DEST_PATH_IMAGE001
。
S3, performing solid-liquid separation on the lithium iron phosphate slurry obtained in the step S2, alternately washing with ethanol and water for multiple times, putting the washed lithium iron phosphate filter cake into a vacuum oven, and drying at 50 ℃ for 24 hours to obtain the nano lithium iron phosphate.
And S4, placing the nano lithium iron phosphate in the step S3 into a tubular furnace for roasting, wherein the roasting temperature is 700 ℃, the roasting time is 5 hours, the protective atmosphere is nitrogen, and taking out the nano lithium iron phosphate after the temperature is reduced to the room temperature to obtain the in-situ carbon-coated nano lithium iron phosphate.
Uniformly mixing the in-situ carbon-coated nano lithium iron phosphate cathode material obtained in the step S4, acetylene black and a binder according to a mass ratio of 8:1:1, adding a proper amount of N-methylpyrrolidone, fully stirring and mixing to obtain uniform slurry, uniformly coating the slurry on an aluminum foil at a thickness of 150 microns by using a film coating device, performing vacuum drying at 120 ℃ for 12 hours, punching and cutting the dried pole piece into a circular electrode piece with the diameter of 14mm, placing the electrode piece, a metal lithium piece, electrolyte (1 mol L-1 LiPF 6-EC/EMC) and a diaphragm (Celgard 2400) in an argon-protected glove box, assembling into a lithium ion button cell, and performing an electrochemical performance test.
Fig. 1 is an XRD spectrum of the precursor powder prepared in this example, in which only ferrous phosphate crystals are found in the XRD spectrum, the corresponding ferrous phosphate standard spectrum is JCPDS #30-0662, and no diffraction peak of lithium phosphate is found, indicating that lithium phosphate in the precursor is amorphous and has no influence on the crystal structure of ferrous phosphate. Fig. 2 is an SEM image of the precursor powder prepared in this embodiment, where fig. 2a is a low-power SEM image, fig. 2b is a high-power SEM image, and as can be seen from fig. 2b, the precursor is formed by stacking bulk particles, as can be seen from fig. 2a, ultrafine nanoparticles are uniformly attached to the surfaces of the bulk particles, the ultrafine nanoparticles are amorphous lithium nano-phosphate, the bulk particles are nano-ferrous phosphate crystals, and the nano-ferrous phosphate is uniformly mixed with the nano-lithium phosphate, which is beneficial to the formation of the subsequent lithium iron phosphate.
Fig. 3 is an XRD spectrum of the in-situ carbon-coated nano lithium iron phosphate prepared in this example, all diffraction peaks of the in-situ carbon-coated nano lithium iron phosphate coincide with a standard spectrum of olivine-type lithium iron phosphate, and corresponding to JCPDS #83-2092, no diffraction peak of carbon is found in the XRD spectrum, because carbon obtained by pyrolysis of the surfactant is amorphous and does not affect the crystal structure of the lithium iron phosphate. Fig. 4 is an SEM image of in-situ carbon-coated nano lithium iron phosphate prepared in the present example. Wherein, fig. 4a is a low-power SEM image, fig. 4b is a high-power SEM image, it can be seen from fig. 4a that the morphology of the in-situ carbon-coated nano lithium iron phosphate is spheroidal particles and the size distribution is uniform, and it can be seen from fig. 4b that the particle size of the in-situ carbon-coated nano lithium iron phosphate is less than or equal to 250nm, the particle distribution is uniform, and the dispersibility is good.
Fig. 5 is an electrochemical performance test of a button half-cell assembled by the in-situ carbon-coated nano lithium iron phosphate prepared in the embodiment, that is, a charging and discharging curve of the first three weeks at 0.1C, and it can be seen from the figure that the in-situ carbon-coated nano lithium iron phosphate is used as an anode material, and has a specific capacity of about 165 mAh/g at 0.1C and a higher specific capacity.
Example 2
A preparation method of an in-situ carbon-coated nano lithium iron phosphate cathode material specifically comprises the following steps:
s1, preparing 0.5 mol/L ferrous sulfate solution, adding 4.5g of polyethylene glycol-6000, preparing 0.5 mol/L phosphoric acid solution, preparing 1.5mol/L lithium hydroxide solution, adding 2.2g of sodium dodecyl sulfate, continuously conveying the three solutions in a concurrent flow manner to a multiphase interface reactor for precipitation reaction, wherein the process is carried out under the protection of nitrogen, and the blue gray lithium iron phosphate precursor slurry is obtained through the reaction. Wherein the reaction temperature is room temperature, the stirring speed is 3000rpm, and the solution flow is 100 mL/min.
S2, aging the lithium iron phosphate precursor slurry obtained in the step S1 for 0.5 hour, adding 80ml of the lithium iron phosphate precursor slurry into a 500ml stainless steel reaction kettle, adding 160ml of N-methylpyrrolidone, setting the stirring speed to be 200rpm, the heat preservation temperature to be 180 ℃, and the heat preservation time to be 5 hours, and carrying out solvothermal reaction under the protection of nitrogen to obtain the lithium iron phosphate slurry.
S3, performing solid-liquid separation on the lithium iron phosphate slurry obtained in the step S2, alternately washing the slurry with ethanol and water for multiple times, putting the washed lithium iron phosphate filter cake into a vacuum oven, and drying the filter cake for 24 hours at 50 ℃ to obtain the nano lithium iron phosphate.
And S4, placing the nano lithium iron phosphate in the step S3 into a tubular furnace for roasting, wherein the roasting temperature is 700 ℃, the roasting time is 5 hours, the protective atmosphere is nitrogen, and the nano lithium iron phosphate is taken out after the temperature is reduced to the room temperature, so that the in-situ carbon-coated nano lithium iron phosphate is obtained.
Uniformly mixing the in-situ carbon-coated nano lithium iron phosphate cathode material obtained in the step S4, acetylene black and a binder according to a mass ratio of 8:1:1, adding a proper amount of N-methylpyrrolidone, fully stirring and mixing to obtain uniform slurry, uniformly coating the slurry on an aluminum foil at a thickness of 150 microns by using a film coating device, performing vacuum drying at 120 ℃ for 12 hours, punching and cutting the dried pole piece into a circular electrode piece with the diameter of 14mm, placing the electrode piece, a lithium metal piece, an electrolyte (1 mol L-1 LiPF 6-EC/EMC) and a diaphragm (Celgard 2400) in an argon-protected glove box, assembling into a lithium ion battery, and performing an electrochemical performance test.
In the embodiment, the prepared precursor powder is a uniform mixture of ferrous phosphate and lithium phosphate, the particle size of the prepared in-situ carbon-coated nano lithium iron phosphate is less than or equal to 250nm, the particle distribution is uniform, and the dispersibility is good. The specific capacity of the in-situ carbon-coated nano lithium iron phosphate prepared by the embodiment at 0.1 ℃ is more than or equal to 160mAh/g, and the specific capacity is higher.
Example 3
A preparation method of an in-situ carbon-coated nano lithium iron phosphate cathode material specifically comprises the following steps:
s1, preparing 1 mol/L ferrous sulfate solution, adding 8g of polyvinyl alcohol, preparing 1.25mol/L diammonium hydrogen phosphate solution, preparing 2.5mol/L lithium hydroxide solution, adding 2.7g of hexadecyl trimethyl ammonium bromide, continuously conveying the three solutions in parallel to a multiphase interface reactor for precipitation reaction under the protection of nitrogen, and reacting to obtain blue gray lithium iron phosphate precursor slurry. Wherein the reaction temperature is room temperature, the stirring speed is 3000rpm, and the solution flow is 100 mL/min.
S2, aging the lithium iron phosphate precursor slurry obtained in the step S1 for 1 hour, adding 120ml of the lithium iron phosphate precursor slurry into a 500ml stainless steel reaction kettle, adding 120ml of N-methyl pyrrolidone, setting the stirring speed to be 200rpm, the heat preservation temperature to be 180 ℃, and the heat preservation time to be 5 hours, and carrying out solvothermal reaction under the protection of nitrogen to obtain the lithium iron phosphate slurry.
S3, performing solid-liquid separation on the lithium iron phosphate slurry obtained in the step S2, alternately washing the slurry with ethanol and water for multiple times, putting the washed lithium iron phosphate filter cake into a vacuum oven, and drying the filter cake for 12 hours at 80 ℃ to obtain the nano lithium iron phosphate.
And S4, placing the nano lithium iron phosphate in the step S3 into a tubular furnace for roasting, wherein the roasting temperature is 650 ℃, the roasting time is 6 hours, the protective atmosphere is nitrogen, and the nano lithium iron phosphate is taken out after the temperature is reduced to the room temperature, so that the in-situ carbon-coated nano lithium iron phosphate is obtained.
Uniformly mixing the in-situ carbon-coated nano lithium iron phosphate cathode material obtained in the step S4, acetylene black and a binder according to a mass ratio of 8:1:1, adding a proper amount of N-methylpyrrolidone, fully stirring and mixing to obtain uniform slurry, uniformly coating the slurry on an aluminum foil at a thickness of 150 microns by using a film coating device, performing vacuum drying at 120 ℃ for 12 hours, punching and cutting the dried pole piece into a circular electrode piece with the diameter of 14mm, placing the electrode piece, a lithium metal piece, an electrolyte (1 mol L-1 LiPF 6-EC/EMC) and a diaphragm (Celgard 2400) in an argon-protected glove box, assembling into a lithium ion battery, and performing an electrochemical performance test.
In the embodiment, the prepared precursor powder is a uniform mixture of ferrous phosphate and lithium phosphate, the particle size of the prepared in-situ carbon-coated nano lithium iron phosphate is less than or equal to 250nm, the particle distribution is uniform, and the dispersibility is good. The specific capacity of the in-situ carbon-coated nano lithium iron phosphate prepared by the embodiment at 0.1 ℃ is more than or equal to 160mAh/g, and the specific capacity is higher.
Example 4
A preparation method of an in-situ carbon-coated nano lithium iron phosphate cathode material specifically comprises the following steps:
s1, preparing 1 mol/L ammonium ferrous sulfate solution, adding 7.8g of polyvinylpyrrolidone, preparing 1.5mol/L ammonium dihydrogen phosphate solution, preparing 3mol/L lithium hydroxide solution, adding 2.5g of sodium dodecyl benzene sulfonate, continuously and parallelly conveying the three solutions into a multiphase interface reactor for precipitation reaction, wherein the process is carried out under the protection of nitrogen, and the blue gray lithium iron phosphate precursor slurry is obtained through reaction. Wherein the reaction temperature is room temperature, the stirring speed is 4000rpm, and the solution flow is 100 mL/min.
S2, aging the lithium iron phosphate precursor slurry obtained in the step S1 for 1 hour, adding 120ml of the lithium iron phosphate precursor slurry into a 500ml stainless steel reaction kettle, adding 120ml of N-methyl pyrrolidone, setting the stirring speed to be 200rpm, the heat preservation temperature to be 180 ℃, and the heat preservation time to be 5 hours, wherein the process is carried out under the protection of nitrogen, and the lithium iron phosphate slurry is obtained through solvothermal reaction.
S3, performing solid-liquid separation on the lithium iron phosphate slurry obtained in the step S2, alternately washing the slurry with ethanol and water for multiple times, putting the washed lithium iron phosphate filter cake into a vacuum oven, and drying the filter cake for 12 hours at 80 ℃ to obtain the nano lithium iron phosphate.
And S4, placing the nano lithium iron phosphate in the step S3 into a tubular furnace for roasting, wherein the roasting temperature is 650 ℃, the roasting time is 6 hours, the protective atmosphere is nitrogen, and the nano lithium iron phosphate is taken out after the temperature is reduced to the room temperature, so that the in-situ carbon-coated nano lithium iron phosphate is obtained.
Uniformly mixing the in-situ carbon-coated nano lithium iron phosphate cathode material obtained in the step S4, acetylene black and a binder according to a mass ratio of 8:1:1, adding a proper amount of N-methylpyrrolidone, fully stirring and mixing to obtain uniform slurry, uniformly coating the slurry on an aluminum foil at a thickness of 150 microns by using a film coating device, performing vacuum drying at 120 ℃ for 12 hours, punching and cutting the dried pole piece into a circular electrode piece with the diameter of 14mm, placing the electrode piece, a lithium metal piece, an electrolyte (1 mol L-1 LiPF 6-EC/EMC) and a diaphragm (Celgard 2400) in an argon-protected glove box, assembling into a lithium ion battery, and performing an electrochemical performance test.
In the embodiment, the prepared precursor powder is a uniform mixture of ferrous phosphate and lithium phosphate, the particle size of the prepared in-situ carbon-coated nano lithium iron phosphate is less than or equal to 250nm, the particle distribution is uniform, and the dispersibility is good. The specific capacity of the in-situ carbon-coated nano lithium iron phosphate prepared by the embodiment at 0.1 ℃ is more than or equal to 160mAh/g, and the specific capacity is higher.
In summary, the above is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims (10)

1. A preparation method of an in-situ carbon-coated nano lithium iron phosphate cathode material is characterized by comprising the following steps of:
the method specifically comprises the following steps:
s1, preparing an iron source solution, a lithium source solution, a phosphorus source solution and a surfactant solution with certain concentrations, and continuously conveying the solutions in parallel flow to a multiphase interface reactor for precipitation reaction, wherein the molar ratio of lithium to iron to phosphorus is Li: fe: p =2-3.5:1:1-1.5, the amount of the surfactant is 0.05-0.5% of the amount of the iron source substance, the concentration of the iron source is 0.1-1 mol/L, under the protection of inert gas, the reaction temperature is 5-80 ℃, the pH value is 6-10, the stirring speed is 3000-5000rpm, and the solution flow is 50-300mL/min, and blue gray lithium iron phosphate precursor slurry is obtained by reaction;
s2, aging the lithium iron phosphate precursor slurry for 0.5-4 hours, then adding part of the slurry into a stainless steel reaction kettle, adding a certain amount of solvent, stirring, and carrying out solvothermal reaction at the temperature of 180-plus-material and 300 ℃ for 2-6 hours under the protection of inert gas to obtain lithium iron phosphate slurry;
s3, carrying out centrifugal separation on the lithium iron phosphate slurry, washing to obtain a lithium iron phosphate filter cake, and drying the filter cake in a vacuum oven to obtain nano lithium iron phosphate;
and S4, placing the nano lithium iron phosphate into a tubular furnace, preserving heat for several hours at a certain temperature, and roasting to obtain the in-situ carbon-coated nano lithium iron phosphate.
2. The preparation method of the in-situ carbon-coated nano lithium iron phosphate cathode material according to claim 1, characterized by comprising the following steps: in S1, the iron source is one of ferrous salt, ferrous sulfate, ferrous oxalate, ferrous acetate, or ferrous ammonium sulfate.
3. The preparation method of the in-situ carbon-coated nano lithium iron phosphate cathode material according to claim 1 or 2, characterized by comprising the following steps: in S1, the lithium source is one of lithium hydroxide and lithium carbonate.
4. The preparation method of the in-situ carbon-coated nano lithium iron phosphate cathode material according to claim 3, characterized by comprising the following steps: in S1, the phosphorus source is one of phosphoric acid, diammonium phosphate, ammonium dihydrogen phosphate, or sodium phosphate.
5. The method for preparing the in-situ carbon-coated nano lithium iron phosphate cathode material as claimed in claim 1, 2 or 4, wherein the method comprises the following steps: in S1, the surfactant is one of polyethylene glycol, polyvinylpyrrolidone, polyvinyl alcohol, sodium dodecyl sulfate, sodium dodecyl benzene sulfonate, or cetyltrimethylammonium bromide.
6. The preparation method of the in-situ carbon-coated nano lithium iron phosphate cathode material according to claim 5, characterized by comprising the following steps: in S2, the solvent is N-methyl-2-pyrrolidone.
7. The preparation method of the in-situ carbon-coated nano lithium iron phosphate cathode material according to claim 6, characterized by comprising the following steps: in S2, the volume ratio of the solvent to the slurry is 1-2.5: 1.
8. The method for preparing the in-situ carbon-coated nano lithium iron phosphate cathode material according to claim 7, characterized by comprising the following steps: in S2, the stirring speed was 150-300 rpm.
9. The method for preparing the in-situ carbon-coated nano lithium iron phosphate cathode material according to claim 8, wherein the method comprises the following steps: in S4, the roasting temperature is 650-750 ℃, and the roasting time is 4-6 hours.
10. An in-situ carbon-coated nano lithium iron phosphate cathode material prepared by the method of claim 1, 2, 4, 6, 8 or 9, which is characterized in that: the in-situ carbon-coated nano lithium iron phosphate has the advantages of uniform particle size less than or equal to 250nm, uniform particle distribution, good dispersibility and specific capacity more than or equal to 160mAh/g at 0.1 ℃.
CN202210499014.7A 2022-05-09 2022-05-09 In-situ carbon-coated nano lithium iron phosphate cathode material and preparation method thereof Pending CN114864896A (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115448285A (en) * 2022-10-26 2022-12-09 华鼎国联四川电池材料有限公司 Method for preparing lithium iron phosphate by taking recycled lithium phosphate as raw material
CN116143099A (en) * 2023-02-24 2023-05-23 南京理工大学 Method for cooperatively synthesizing lithium iron phosphate electrode material by using ethylene glycol and sodium dodecyl sulfate
CN116281917A (en) * 2023-03-01 2023-06-23 湖北宇浩高科新材料有限公司 Battery-grade anhydrous ferric phosphate, preparation method and application thereof, and preparation method of lithium iron phosphate
TWI827275B (en) * 2022-09-27 2023-12-21 台灣立凱電能科技股份有限公司 Preparation method of lithium iron phosphate cathode material

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
TWI827275B (en) * 2022-09-27 2023-12-21 台灣立凱電能科技股份有限公司 Preparation method of lithium iron phosphate cathode material
CN115448285A (en) * 2022-10-26 2022-12-09 华鼎国联四川电池材料有限公司 Method for preparing lithium iron phosphate by taking recycled lithium phosphate as raw material
CN115448285B (en) * 2022-10-26 2024-02-06 华鼎国联四川电池材料有限公司 Method for preparing lithium iron phosphate by taking recycled lithium phosphate as raw material
CN116143099A (en) * 2023-02-24 2023-05-23 南京理工大学 Method for cooperatively synthesizing lithium iron phosphate electrode material by using ethylene glycol and sodium dodecyl sulfate
CN116143099B (en) * 2023-02-24 2024-03-19 南京理工大学 Method for cooperatively synthesizing lithium iron phosphate electrode material by using ethylene glycol and sodium dodecyl sulfate
CN116281917A (en) * 2023-03-01 2023-06-23 湖北宇浩高科新材料有限公司 Battery-grade anhydrous ferric phosphate, preparation method and application thereof, and preparation method of lithium iron phosphate
CN116281917B (en) * 2023-03-01 2024-02-09 湖北宇浩高科新材料有限公司 Battery-grade anhydrous ferric phosphate, preparation method and application thereof, and preparation method of lithium iron phosphate

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