CN108039466B - Preparation method of titanium silicide coated lithium iron phosphate composite material - Google Patents

Preparation method of titanium silicide coated lithium iron phosphate composite material Download PDF

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CN108039466B
CN108039466B CN201711266488.2A CN201711266488A CN108039466B CN 108039466 B CN108039466 B CN 108039466B CN 201711266488 A CN201711266488 A CN 201711266488A CN 108039466 B CN108039466 B CN 108039466B
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lithium
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iron phosphate
titanium silicide
composite material
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CN108039466A (en
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郭钰静
樊少娟
杨茂萍
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Hefei Gotion High Tech Power Energy Co Ltd
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Hefei Guoxuan High Tech Power Energy 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
    • H01M4/366—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
    • 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
    • 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
    • H01M4/624—Electric conductive fillers
    • 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 discloses a preparation method of a titanium silicide coated lithium iron phosphate composite material, which comprises the following steps of weighing a lithium source, an iron source and a phosphorus source according to the molar ratio of the lithium element to the iron element to the phosphorus element of 1-1.05: 1:1, carrying out wet ball milling on the lithium source, the iron source and the phosphorus source, drying and crushing to obtain L iFePO4Precursor L iFePO4Adding the precursor into a tubular furnace, heating to 680-750 ℃ at the speed of 2-8 ℃/min under the protective atmosphere, carrying out heat preservation and calcination for 6-12h, stopping introducing the protective atmosphere, adding a silicon source and a titanium source, carrying out deposition reaction for 5-30min, calcining for 0-6h under the protective atmosphere, and cooling to room temperature to obtain the titanium silicide coated lithium iron phosphate composite material. The preparation method of the titanium silicide coated lithium iron phosphate composite material provided by the invention has the advantages that the process is simple, the electron conductivity of the lithium iron phosphate material is improved, and the rate capability and the cycle performance of the lithium iron phosphate material are improved.

Description

Preparation method of titanium silicide coated lithium iron phosphate composite material
Technical Field
The invention relates to the technical field of positive electrode materials for lithium ion batteries, in particular to a preparation method of a titanium silicide coated lithium iron phosphate composite material.
Background
With the development of lithium ion battery technology, secondary lithium batteries have been widely used in the fields of electronic products, electric vehicles, hybrid electric vehicles, large-scale power grids, new energy storage devices, and the like. Compared with other lithium battery anode materials, the lithium iron phosphate has the characteristics of high safety, long cycle life, high specific capacity, good stability, rich resources, low price, no toxicity, environmental protection and the like, and is widely considered to be one of the lithium battery anode materials with the greatest development prospect. In addition, the lithium iron phosphate has good high-temperature cycle performance and does not explode. Lithium iron phosphate is also an excellent anode material of a large-scale lithium ion battery pack, and has a larger application space in the aspect of large-scale power batteries.
However, the self-structural characteristics of lithium iron phosphate having an olivine structure determine that lithium ions can be conducted only in one dimension along the (010) direction during charging and discharging, resulting in a low electronic conductivity (10)-9-10-10S·cm-1). The low electronic conductivity limits the high-rate charge-discharge performance of the lithium iron phosphate battery, thereby limiting the application of the lithium iron phosphate in the field of requiring large-current rapid charge-discharge. The most common method to solve this problem is surface carbon coating. Although carbon coating can improve the battery performance of lithium iron phosphate to a certain extent, carbon coating has more difficulties and challenges in practical production. For example, when the carbon content is low, a complete and uniform coating layer cannot be formed on the surface of lithium iron phosphate, and sufficient conductivity cannot be obtained; as the carbon content increases, the coating layer thickens, not only reducing the tap density of the active material but also blocking the diffusion path of lithium ions.
The titanium silicide compound has excellent conductivity, extremely high chemical stability and corrosion resistance, is not easy to decompose, and does not influence the main reaction as a modified substance due to impurities. Due to the properties, the titanium silicide compound has a very obvious effect on the modification of lithium iron phosphate battery materials.
Disclosure of Invention
Based on the technical problems in the background art, the invention provides a preparation method of a titanium silicide coated lithium iron phosphate composite material, which has a simple process, can improve the electron conduction performance of a lithium iron phosphate material, and improves the rate capability and the cycle performance of the lithium iron phosphate material.
The invention provides a preparation method of a titanium silicide coated lithium iron phosphate composite material, which comprises the following steps:
s1, weighing a lithium source, an iron source and a phosphorus source according to the molar ratio of the lithium element, the iron element and the phosphorus element of 1-1.05: 1:1, performing wet ball milling on the lithium source, the iron source and the phosphorus source, drying and crushing to obtain L iFePO4A precursor;
s2, L iFePO in S14Adding the precursor into a tube furnace, and heating at the speed of 2-8 ℃/min under the protective atmosphereAnd (3) performing heat preservation and calcination at 750 ℃ of 680-fold, stopping introducing protective atmosphere, adding a silicon source and a titanium source, performing deposition reaction for 5-30min, calcining for 0-6h in the protective atmosphere, and cooling to room temperature to obtain the titanium silicide coated lithium iron phosphate composite material.
Preferably, in S1, the lithium source is one or more of lithium carbonate, lithium acetate, lithium oxalate, lithium dihydrogen phosphate, and lithium hydroxide.
Preferably, in S1, the iron source is one or more of ferric oxide, ferroferric oxide, ferrous oxide, ferric hydroxide, ferric phosphate, and ferrous oxalate.
Preferably, in S1, the phosphorus source is one or more of lithium dihydrogen phosphate, ammonium dihydrogen phosphate, and diammonium hydrogen phosphate.
Preferably, in S2, the protective atmosphere is a nitrogen atmosphere or an argon atmosphere.
Preferably, in S2, the silicon source and the titanium source are gaseous SiH respectively4And liquid TiCl4And with N2As a carrier gas.
Preferably, the TiCl4Heating in water bath at 30-40 deg.C, and maintaining at TiCl4The temperature of the pipeline is maintained at 45-55 ℃.
Preferably, N is used by bubbling2Mixing TiCl4Is introduced into a gas mixing chamber and SiH4The mixed gas obtained by mixing enters the reaction chamber to carry out deposition reaction, and the total flow of the mixed gas is controlled at 500-1200 sccm.
Preferably, in the mixed gas, SiH4In a molar percentage of 0.33-0.5%, TiCl4Is 0.33-1.67 percent.
Preferably, TiCl4And SiH4In a molar ratio of 1 to 3: 1.
preferably, the titanium silicide is Ti5Si3、TiSi2Or a mixture of both.
According to the preparation method of the titanium silicide coated lithium iron phosphate composite material, a titanium source and a silicon source are introduced in the calcination process of preparing lithium iron phosphate, the titanium silicide coated lithium iron phosphate composite material is synthesized by using a chemical vapor deposition method, and the thickness and the shape of the coating layer can be adjusted by adjusting the molar ratio of silicon to titanium, the deposition time and the reaction temperature in the synthesis process, so that the titanium silicide coated lithium iron phosphate composite material is obtained; compared with the prior art, the invention has the beneficial effects that: 1. the titanium silicide prepared by the invention has very uniform coating on lithium iron phosphate, and has no barrier effect on the diffusion of lithium ions; 2. the conductivity of the lithium iron phosphate composite material coated by the titanium silicide prepared by the invention is greatly improved, and the rate capability and the cycle performance of the lithium iron phosphate material are greatly improved; 3. the lithium iron phosphate composite material coated by the method has high tap density, and is more beneficial to the miniaturization of a high-capacity lithium ion battery.
Drawings
Fig. 1 is a charge-discharge curve of a battery assembled by the titanium silicide coated lithium iron phosphate composite material prepared in example 1 of the present invention at different rates.
Detailed Description
The technical solution of the present invention will be described in detail below with reference to specific examples.
Example 1
The invention provides a preparation method of a titanium silicide coated lithium iron phosphate composite material, which comprises the following steps:
s1, respectively weighing lithium carbonate, ferrous oxalate and ammonium dihydrogen phosphate according to the molar ratio of the lithium element, the iron element and the phosphorus element of 1: 1:1 to prepare raw materials, ball-milling the lithium carbonate, the ferrous oxalate and the ammonium dihydrogen phosphate by a wet method, drying in vacuum, and ball-milling and crushing to prepare L iFePO4A precursor;
s2, L iFePO in S14Adding the precursor into a tube furnace, heating to 680 ℃ at the speed of 5 ℃/min under the protective nitrogen atmosphere, carrying out heat preservation and calcination for 10h, closing the protective nitrogen, and carrying out bubbling by using N2Mixing TiCl4Is introduced into a gas mixing chamber and SiH4Mixing uniformly to obtain TiCl4、SiH4And N2The mixed gas of (2) is evenly mixed TiCl4、SiH4And N2Introduction of the mixed gasThe deposition reaction is carried out for 10min in a chamber, wherein, TiCl4And SiH4The molar ratio of the titanium silicide to the iron phosphate composite material is 3:1, the total flow of the mixed gas is 1000sccm, the mixed gas is closed, then the mixture is calcined for 2 hours under protective nitrogen, and the mixture is cooled to room temperature to obtain the titanium silicide coated iron phosphate composite material.
The titanium silicide coated lithium iron phosphate composite material prepared in this example was prepared as a titanium silicide coated lithium iron phosphate composite material in the following weight proportions: SP: the button cell is assembled by PVDF (polyvinylidene fluoride) in a ratio of 8:1:1, a Clgard2300 type diaphragm is adopted, a metal lithium sheet is used as a counter electrode, and charge and discharge tests under different multiplying powers are carried out, the result is shown in figure 1, as can be seen from figure 1, the 0.2C specific discharge capacity is 165mAh/g, the 1C specific discharge capacity is 160mAh/g, the 2C specific discharge capacity is 158mAh/g, and the 3C specific discharge capacity is 155 mAh/g.
Example 2
The invention provides a preparation method of a titanium silicide coated lithium iron phosphate composite material, which comprises the following steps:
s1, respectively weighing lithium hydroxide, ferrous oxalate and ammonium dihydrogen phosphate according to the molar ratio of the lithium element, the iron element and the phosphorus element of 1.02: 1:1 to prepare raw materials, carrying out wet ball milling on the lithium hydroxide, the ferrous oxalate and the ammonium dihydrogen phosphate, drying in vacuum, and carrying out ball milling and crushing to obtain L iFePO4A precursor;
s2, L iFePO in S14Adding the precursor into a tube furnace, heating to 700 ℃ at the speed of 2 ℃/min under the protective argon atmosphere, carrying out heat preservation and calcination for 8h, closing the protective argon, and mixing uniformly TiCl4、SiH4And N2Introducing the mixed gas into a reaction chamber for deposition reaction for 15min, wherein TiCl4And SiH4The molar ratio of the titanium silicide to the iron phosphate composite material is 2:1, the total flow of the mixed gas is 800sccm, the mixed gas is closed, then the mixed gas is calcined for 2 hours under protective argon, and the mixed gas is cooled to room temperature to obtain the titanium silicide coated iron phosphate composite material.
Example 3
The invention provides a preparation method of a titanium silicide coated lithium iron phosphate composite material, which comprises the following steps:
s1, according to the molar ratio of the lithium element to the iron element to the phosphorus element of 1.05: 1:1 each ofWeighing lithium carbonate and iron phosphate for preparing materials, ball-milling the lithium carbonate and the iron phosphate by a wet method, drying in vacuum, and ball-milling and crushing to obtain L iFePO4A precursor;
s2, L iFePO in S14Adding the precursor into a tube furnace, heating to 730 ℃ at the speed of 8 ℃/min under the protective nitrogen atmosphere, carrying out heat preservation and calcination for 10h, closing the protective nitrogen, and mixing uniformly TiCl4、SiH4And N2Introducing the mixed gas into a reaction chamber for deposition reaction for 20min, wherein TiCl4And SiH4The molar ratio of the titanium silicide to the iron phosphate composite material is 1:1, the total flow of the mixed gas is 1200sccm, the mixed gas is closed, and then the titanium silicide coated iron phosphate composite material is obtained by cooling to room temperature under protective nitrogen.
Example 4
The invention provides a preparation method of a titanium silicide coated lithium iron phosphate composite material, which comprises the following steps:
s1, respectively weighing lithium carbonate, ferrous oxalate and ammonium dihydrogen phosphate according to the molar ratio of the lithium element, the iron element and the phosphorus element of 1.01: 1:1 to prepare materials, ball-milling the lithium carbonate, the ferrous oxalate and the ammonium dihydrogen phosphate by a wet method, drying in vacuum, and ball-milling and crushing to prepare L iFePO4A precursor;
s2, L iFePO in S14Adding the precursor into a tube furnace, heating to 750 ℃ at the speed of 4 ℃/min under the protective nitrogen atmosphere, carrying out heat preservation and calcination for 6h, closing the protective nitrogen, and mixing uniformly TiCl4、SiH4And N2Introducing the mixed gas into a reaction chamber for deposition reaction for 30min, wherein TiCl4And SiH4The molar ratio of the titanium silicide to the iron phosphate composite material is 3:1, the total flow of the mixed gas is 500sccm, the mixed gas is closed, then the mixture is calcined for 4 hours under protective nitrogen, and the mixture is cooled to room temperature to obtain the titanium silicide coated iron phosphate composite material.
Example 5
The invention provides a preparation method of a titanium silicide coated lithium iron phosphate composite material, which comprises the following steps:
s1, mixing the following raw materials in a molar ratio of lithium element, iron element and phosphorus element of 1: 1:1, weighing a lithium source, an iron source and a phosphorus source; mixing lithium source and ironCarrying out wet ball milling on the source and the phosphorus source, drying and crushing to obtain L iFePO4A precursor;
s2, L iFePO in S14Adding the precursor into a tube furnace, heating to 750 ℃ at the speed of 2 ℃/min under the protective atmosphere, carrying out heat preservation and calcination for 6h, stopping introducing the protective atmosphere, adding a silicon source and a titanium source, carrying out a deposition reaction for 30min, and then cooling to room temperature under the protective atmosphere to obtain the titanium silicide coated lithium iron phosphate composite material.
Example 6
The invention provides a preparation method of a titanium silicide coated lithium iron phosphate composite material, which comprises the following steps:
s1, weighing a lithium source, an iron source and a phosphorus source according to the molar ratio of the lithium element to the iron element to the phosphorus element of 1.05: 1:1, performing wet ball milling on the lithium source, the iron source and the phosphorus source, drying and crushing to obtain L iFePO4A precursor;
s2, L iFePO in S14Adding the precursor into a tube furnace, heating to 680 ℃ at the speed of 8 ℃/min under the protective atmosphere, carrying out heat preservation and calcination for 12h, stopping introducing the protective atmosphere, adding a silicon source and a titanium source, carrying out deposition reaction for 5min, then calcining for 6h under the protective atmosphere, and cooling to room temperature to obtain the titanium silicide coated lithium iron phosphate composite material.
Example 7
The invention provides a preparation method of a titanium silicide coated lithium iron phosphate composite material, which comprises the following steps:
s1, weighing the lithium source, the iron source and the phosphorus source according to the molar ratio of the lithium element to the iron element to the phosphorus element of 1.03: 1:1, carrying out wet ball milling on the lithium source, the iron source and the phosphorus source, drying and crushing to obtain L iFePO4A precursor; wherein the lithium source is lithium carbonate; the iron source is ferric oxide; the phosphorus source is ammonium dihydrogen phosphate;
s2, L iFePO in S14Adding the precursor into a tube furnace, heating to 690 ℃ at the speed of 3 ℃/min under the protective atmosphere, carrying out heat preservation calcination for 11h, stopping introducing the protective atmosphere, adding a silicon source and a titanium source, carrying out a deposition reaction for 16min, then carrying out calcination for 2h under the protective atmosphere, and cooling to room temperature to obtain the titanium silicideCoating the lithium iron phosphate composite material; wherein the protective atmosphere is a nitrogen atmosphere; the silicon source and the titanium source are respectively gaseous SiH4And liquid TiCl4And with N2As a carrier gas; the TiCl4Heating in water bath to maintain 30 deg.C, TiCl4The temperature of the pipeline is maintained at 55 ℃; by bubbling with N2Mixing TiCl4Is introduced into a gas mixing chamber and SiH4After the mixed gas is obtained by mixing, the mixed gas enters a reaction chamber to carry out deposition reaction, and the total flow of the mixed gas is controlled at 600 sccm; in a mixed gas, SiH4Is 0.33% of TiCl4Is 1.67%.
Example 8
The invention provides a preparation method of a titanium silicide coated lithium iron phosphate composite material, which comprises the following steps:
s1, weighing a lithium source, an iron source and a phosphorus source according to the molar ratio of the lithium element to the iron element to the phosphorus element of 1.01: 1:1, performing wet ball milling on the lithium source, the iron source and the phosphorus source, drying and crushing to obtain L iFePO4A precursor; wherein the lithium source is a mixture of lithium carbonate and lithium acetate, and the weight ratio of the lithium carbonate to the lithium acetate is 3: 2; the iron source is ferroferric oxide; the phosphorus source is ammonium dihydrogen phosphate;
s2, L iFePO in S14Adding the precursor into a tubular furnace, heating to 720 ℃ at the speed of 7 ℃/min under the protective atmosphere, carrying out heat preservation and calcination for 7h, stopping introducing the protective atmosphere, adding a silicon source and a titanium source, carrying out a deposition reaction for 25min, then calcining for 5h under the protective atmosphere, and cooling to room temperature to obtain the titanium silicide coated lithium iron phosphate composite material; wherein the protective atmosphere is a nitrogen atmosphere; the silicon source and the titanium source are respectively gaseous SiH4And liquid TiCl4And with N2As a carrier gas; the TiCl4Heating in water bath to maintain 40 deg.C, TiCl4The temperature of the pipeline is maintained at 55 ℃; by bubbling with N2Mixing TiCl4Is introduced into a gas mixing chamber and SiH4After the mixed gas is obtained by mixing, the mixed gas enters a reaction chamber to carry out deposition reaction, and the total flow of the mixed gas is controlled at 1100 sccm; in a mixed gas, SiH4Is 0.5% of TiCl4Is 0.33%.
Example 9
The invention provides a preparation method of a titanium silicide coated lithium iron phosphate composite material, which comprises the following steps:
s1, weighing a lithium source, an iron source and a phosphorus source according to the molar ratio of the lithium element to the iron element to the phosphorus element of 1.02: 1:1, performing wet ball milling on the lithium source, the iron source and the phosphorus source, drying and crushing to obtain L iFePO4A precursor; the lithium source is a mixture of lithium carbonate, lithium oxalate and lithium hydroxide, and the weight ratio of the lithium carbonate to the lithium oxalate to the lithium hydroxide is 3:2: 1; the iron source is a mixture of ferric oxide, ferrous oxide and ferrous oxalate, and the weight ratio of the ferric oxide to the ferrous oxalate is 4:3: 2; the phosphorus source is a mixture of ammonium dihydrogen phosphate and diammonium hydrogen phosphate, and the weight ratio of the ammonium dihydrogen phosphate to the diammonium hydrogen phosphate is 4: 5;
s2, L iFePO in S14Adding the precursor into a tube furnace, heating to 700 ℃ at the speed of 5 ℃/min under the protective atmosphere, carrying out heat preservation and calcination for 8h, stopping introducing the protective atmosphere, adding a silicon source and a titanium source, carrying out a deposition reaction for 20min, then carrying out calcination for 3h under the protective atmosphere, and cooling to room temperature to obtain the titanium silicide coated lithium iron phosphate composite material; wherein the protective atmosphere is an argon atmosphere; the silicon source and the titanium source are respectively gaseous SiH4And liquid TiCl4And with N2As a carrier gas; the TiCl4Heating in water bath to 35 deg.C, and maintaining TiCl4The temperature of the pipeline is maintained at 50 ℃; by bubbling with N2Mixing TiCl4Is introduced into a gas mixing chamber and SiH4After mixed, mixed gas is obtained and then enters a reaction chamber of the tubular furnace for deposition reaction, and the total flow of the mixed gas is controlled at 800 sccm; in a mixed gas, SiH4Is 0.38% of TiCl4Is 1.2%.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.

Claims (11)

1. A preparation method of a titanium silicide coated lithium iron phosphate composite material is characterized by comprising the following steps:
s1, weighing a lithium source, an iron source and a phosphorus source according to the molar ratio of the lithium element, the iron element and the phosphorus element of 1-1.05: 1:1, performing wet ball milling on the lithium source, the iron source and the phosphorus source, drying and crushing to obtain L iFePO4A precursor;
s2, L iFePO in S14Adding the precursor into a tube furnace, heating to 680-750 ℃ at the speed of 2-8 ℃/min under the protective atmosphere, carrying out heat preservation and calcination for 6-12h, stopping introducing the protective atmosphere, and carrying out N bubbling on the protective atmosphere2Mixing TiCl4Is introduced into a gas mixing chamber and SiH4And after mixing to obtain mixed gas, entering a reaction chamber for deposition reaction for 5-30min, calcining for 0-6h in protective atmosphere, and cooling to room temperature to obtain the titanium silicide coated lithium iron phosphate composite material.
2. The method of claim 1, wherein in step S1, the lithium source is one or more selected from the group consisting of lithium carbonate, lithium acetate, lithium oxalate, lithium dihydrogen phosphate, and lithium hydroxide.
3. The method of preparing the titanium silicide coated lithium iron phosphate composite material according to claim 1 or 2, wherein the iron source is ferric oxide, ferroferric oxide, ferrous oxide, ferric hydroxide, ferric phosphate, ferrous oxalate at S1.
4. The method of claim 1 or 2, wherein the phosphorus source is one or more of lithium dihydrogen phosphate, ammonium dihydrogen phosphate, and diammonium hydrogen phosphate at S1.
5. The method of claim 3, wherein the phosphorus source is one or more of lithium dihydrogen phosphate, ammonium dihydrogen phosphate, and diammonium hydrogen phosphate at S1.
6. The method for preparing a titanium silicide-coated lithium iron phosphate composite material according to claim 1 or 2, wherein the protective atmosphere is a nitrogen atmosphere or an argon atmosphere at S2.
7. The method for preparing the titanium silicide-coated lithium iron phosphate composite according to claim 3, wherein the protective atmosphere is a nitrogen atmosphere or an argon atmosphere at S2.
8. The method for preparing the titanium silicide-coated lithium iron phosphate composite according to claim 4, wherein the protective atmosphere is a nitrogen atmosphere or an argon atmosphere at S2.
9. The method of claim 1, wherein the TiCl coated lithium iron phosphate composite is prepared by the method comprising4Heating in water bath at 30-40 deg.C, and maintaining at TiCl4The temperature of the pipeline is maintained at 45-55 ℃.
10. The method of claim 1, wherein the SiH is in a mixed gas4In a molar percentage of 0.33-0.5%, TiCl4The mole percentage of (A) is 0.33-1.67%; TiCl (titanium dioxide)4And SiH4In a molar ratio of 1 to 3: 1.
11. the method of preparing the titanium silicide-coated lithium iron phosphate composite of any of claims 1-2, 5, 7-10, wherein the titanium silicide is Ti5Si3、TiSi2Or a mixture of both.
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WO2013024739A1 (en) * 2011-08-16 2013-02-21 三洋電機株式会社 Active material for non-aqueous electrolyte secondary battery, non-aqueous electrolyte secondary battery, and manufacturing method for active material for non-aqueous electrolyte secondary battery
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