CN117263254A - Lithium ferrite material and preparation method and application thereof - Google Patents

Lithium ferrite material and preparation method and application thereof Download PDF

Info

Publication number
CN117263254A
CN117263254A CN202311560612.1A CN202311560612A CN117263254A CN 117263254 A CN117263254 A CN 117263254A CN 202311560612 A CN202311560612 A CN 202311560612A CN 117263254 A CN117263254 A CN 117263254A
Authority
CN
China
Prior art keywords
lithium
source
lithium ferrite
iron
ferrite material
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
CN202311560612.1A
Other languages
Chinese (zh)
Other versions
CN117263254B (en
Inventor
请求不公布姓名
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Shanghai Langyi Functional Materials Co ltd
Original Assignee
Shanghai Langyi Functional Materials Co ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Shanghai Langyi Functional Materials Co ltd filed Critical Shanghai Langyi Functional Materials Co ltd
Priority to CN202311560612.1A priority Critical patent/CN117263254B/en
Publication of CN117263254A publication Critical patent/CN117263254A/en
Application granted granted Critical
Publication of CN117263254B publication Critical patent/CN117263254B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G49/00—Compounds of iron
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B32/00—Carbon; Compounds thereof
    • C01B32/05—Preparation or purification of carbon not covered by groups C01B32/15, C01B32/20, C01B32/25, C01B32/30
    • 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
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/523—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron for non-aqueous cells
    • 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
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2002/00—Crystal-structural characteristics
    • C01P2002/70—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data
    • C01P2002/72—Crystal-structural characteristics defined by measured X-ray, neutron or electron diffraction data by d-values or two theta-values, e.g. as X-ray diagram
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/01—Particle morphology depicted by an image
    • C01P2004/04—Particle morphology depicted by an image obtained by TEM, STEM, STM or AFM
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/60—Particles characterised by their size
    • C01P2004/61—Micrometer sized, i.e. from 1-100 micrometer
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/60—Particles characterised by their size
    • C01P2004/62—Submicrometer sized, i.e. from 0.1-1 micrometer
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/80—Particles consisting of a mixture of two or more inorganic phases
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/40—Electric properties
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/80—Compositional purity
    • 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
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/028—Positive electrodes
    • 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

Landscapes

  • Chemical & Material Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Materials Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Battery Electrode And Active Subsutance (AREA)

Abstract

The invention provides a lithium ferrite material, a preparation method and application thereof. The preparation method of the lithium ferrite material comprises the following steps: s1, sintering a lithium ferrite precursor to obtain a product I; the preparation method of the lithium ferrite precursor comprises the following steps: grinding an iron source and a lithium source in water, and then drying and crushing; the particle diameter after grinding is D 90 Less than 150nm; lithium ferrite precursor D 90 ＜6.0μm，D 10 ＞0.3μm，D 50 > 0.8 μm; s2, carrying out carbon coating on the product I and a carbon source to obtain the lithium ferrite material, wherein the lithium ferrite material D 10 Is > 0.3 μm, D 50 Is > 0.8 μm, D 90 Is < 6.0 μm. The lithium ferrite material prepared by the preparation method provided by the invention can realize a better carbon coating structure and lower fineness, and the battery has good specific capacity and cycle performance when being used as a lithium supplementing agent of an electrode material.

Description

Lithium ferrite material and preparation method and application thereof
Technical Field
The invention relates to a lithium ferrite material, a preparation method and application thereof.
Background
In recent years, lithium ion batteries are widely focused and developed in the field of new energy, can be widely applied to power batteries, energy storage power stations and 3C batteries, and have the advantage of environmental protection. However, during the first charge of the lithium ion battery, the formation of the SEI film permanently consumes a large amount of lithium from the positive electrode, reducing the capacity and energy density of the lithium ion battery. There have been a great deal of research on lithium supplementation by adding a lithium supplementing agent to a positive electrode material to offset the loss of irreversible lithium caused by the formation of an SEI film, thereby improving the total capacity and energy density of a battery.
Currently, lithium ferrite (Li 5 FeO 4 ) Materials used as positive electrode lithium supplementing additives are widely used because of good lithium supplementing effect. The conventional method for preparing lithium ferrite is to synthesize a lithium ferrite precursor by a high-temperature solid phase method and then carry out carbon coating, or synthesize the carbon-coated lithium ferrite by a one-step method by an in-situ high-temperature solid phase method.
In the prior art, lithium carbonate and ferric oxide are generally adopted as raw materials to prepare lithium ferrite, a high-temperature solid-phase sintering method is mainly adopted, the sintering temperature is usually 700-900 ℃, the sintering time is 10-72 hours, the sintering temperature is high, the sintering time is long, primary particles with smaller particle sizes can be fused into primary particles with larger particle sizes or are agglomerated into secondary particles, the problem is generally existed in the field, in order to solve the problem, the size of the primary particles is often reduced through nanocrystallization, carbon coating prevents the fusion among the particles, the sintering temperature is reduced or the sintering time is reduced, the fusion of smaller primary particles is prevented, but the effect is limited, the fusion can occur to a certain extent, the carbon coating structure can be damaged to a certain extent in the subsequent crushing operation, and the crushing effect is limited, so that the carbon-coated lithium ferrite product with complete carbon coating structure and smaller fineness is difficult to prepare.
Disclosure of Invention
The invention mainly aims to overcome the defects of incomplete coating structure and large fineness of products of lithium ferrite carbon prepared by a preparation method in the prior art, and provides a lithium ferrite material, and a preparation method and application thereof. The lithium ferrite material prepared by the preparation method provided by the invention can realize a better carbon coating structure and lower fineness, and the battery has good specific capacity and cycle performance when being used as a lithium supplementing agent of an electrode material.
The invention provides a preparation method of a lithium ferrite material, which comprises the following steps:
s1, sintering a lithium ferrite precursor to obtain a product I;
the preparation method of the lithium ferrite precursor comprises the following steps: grinding an iron source and a lithium source in water, and then drying and crushing; the particle diameter after grinding is D 90 Less than 150nm; the lithium ferrite precursor D 90 ＜6.0μm，D 10 ＞0.3μm，D 50 > 0.8 μm; the molar ratio of the lithium element to the iron element in the lithium ferrite precursor is 5.5-8.0:1; the sintering temperature is 800-1000 ℃; the lithium ferrite precursor flows in sintering equipment during sintering, and the gas flow rate in the sintering equipment is 10-30L/min; the stirring speed of the sintering equipment is 200-1500r/min;
s2, carrying out carbon coating on the product I and a carbon source to obtain the lithium ferrite material;
d of the lithium ferrite material 10 Is > 0.3 μm, D 50 Is > 0.8 μm, D 90 Is < 6.0 μm.
D of the lithium ferrite material 10 Is > 0.3 μm, D of the lithium ferrite material 50 Is > 0.8 mu m, D of the lithium ferrite material 90 Is < 6.0 μm.
In the invention, the D of the lithium ferrite precursor 50 May be > 2.0 μm.
In the invention, the lithium ferrite precursor comprises an iron source and a lithium source.
Wherein the iron source may be an iron-containing compound conventionally used in the art, preferably a water-soluble iron-containing compound or a water-insoluble iron-containing compound; the water-soluble iron-containing compound is preferably one or more of ferric nitrate, ferric sulfate and ferric chloride; the non-water-soluble iron-containing compound is preferably one or more of iron acetate, iron sesquioxide and iron sesquioxide.
Wherein the lithium source may be a lithium-containing compound conventionally used in the art, preferably a water-soluble lithium-containing compound and an insoluble lithium-containing compound; the water-soluble lithium-containing compound is preferably one or more of lithium nitrate, lithium acetate and lithium chloride; the non-water-soluble lithium-containing compound is preferably one or more of lithium carbonate, lithium hydroxide and lithium acetate.
In the present invention, water-solubility is understood to mean that the material is highly soluble in water and can be dissolved substantially entirely.
In some embodiments, the lithium source is lithium carbonate and the iron source is ferric oxide.
The reaction route is as follows: 5LiCO 3 + Fe 2 O 3 →2Li 5 FeO 4 +5CO 2 ↑。
In some embodiments, the lithium source is lithium hydroxide and the iron source is ferric oxide.
The reaction route is as follows: 10LiOH H 2 O+Fe 2 O 3 →2Li 5 FeO 4 +15H 2 O。
In some embodiments, at least one of the iron source and the lithium source is a soluble compound. The adoption of at least one water-soluble raw material is more beneficial to increasing the contact area of reactants and improving the reaction degree so as to realize the uniform mixing of the molecular layers of the raw materials and more beneficial to the preparation of lithium ferrite.
In some embodiments, the iron source is a soluble iron-containing compound, the lithium source is a soluble lithium-containing compound, for example, the iron source is ferric nitrate, and the lithium source is lithium nitrate.
In some embodiments, the iron source is a soluble iron-containing compound, the lithium source is an insoluble lithium-containing compound, for example, the iron source is ferric nitrate, and the lithium source is lithium carbonate.
In some embodiments, the iron source is an insoluble iron-containing compound, the lithium source is a soluble lithium-containing compound, the iron source is ferric oxide, and the lithium source is lithium nitrate.
In the present invention, the molar ratio of the lithium element to the iron element in the lithium ferrite precursor may be 5.5-7.0:1, for example, 5.5:1 or 6.0:1.
In S1, the milling operation and conditions may be conventional milling operations, such as sand milling or ball milling.
Preferably, the grinding is performed using a sand mill. The sand mill is preferably a vertical sand mill, a horizontal sand mill (e.g., a nanoscale horizontal sand mill), a basket sand mill, or a double cone rod sand mill. The particle size of the beads used in the sand mill is preferably 0.1-3.0mm, for example 0.3mm or 0.4mm. The beads used in the sander are preferably zirconia beads. The grinding process is controlled to be as small as possible in most of the sand mills, and materials are sufficiently ground as much as possible in the precursor preparation stage, so that precursors with uniform fineness are obtained, and the fineness uniformity of lithium ferrite materials is improved.
In S1, the drying is preferably spray drying.
In S1, the drying temperature is preferably 120 ℃ to 180 ℃, for example 130 ℃.
In S1, the crushing means may be conventional crushing means used in the art, such as air stream crushing or mechanical crushing. The purpose of the crushing is to refine the material.
The pressure of the gas stream disruption is preferably 5MPa to 10MPa, for example 6MPa;
the frequency of the gas stream disruption is preferably 70Hz to 130Hz, for example 80Hz.
In S1, the sintering apparatus may be a fluidized bed or a rotary kiln, preferably a fluidized bed. Compared with the traditional static or dynamic sintering mode of the kiln or roller kiln, when the fluidized bed or rotary kiln is adopted for sintering, materials fully flow in the cavity, and the problems of fusion and the like caused by full contact between particles are avoided, so that lithium ferrite samples with small fineness and uniform particles can be obtained even if the kiln is sintered at high temperature for a long time.
In S1, the gas flow rate may be 12-20L/min, for example 15L/min.
In S1, the stirring speed may be 500-1200r/min, for example 1000r/min.
In S1, the sintering temperature may be 850-950 ℃, e.g. 850 ℃ or 900 ℃.
In S1, the sintering time may be 10-40 hours, for example 20 hours or 30 hours.
In S1, the gas atmosphere of the sintering may be air and/or an inert atmosphere, and the gas of the inert atmosphere is preferably argon and/or nitrogen. In the traditional sintering, inert gas is adopted, particularly, in the in-situ carbon-coated lithium ferrite synthesis process, only inert gas is adopted for sintering, and carbon is consumed by air for sintering.
S2, the carbon source can be a gas carbon source or a liquid carbon source; the gaseous carbon source is preferably CH 4 And C 2 H 4 The method comprises the steps of carrying out a first treatment on the surface of the The liquid carbon source is preferably an aqueous organic solution or a liquid organic matter;
the aqueous organic matter solution is preferably one or more of aqueous dextrose solution, sucrose solution, starch solution, citric acid solution, phenolic resin solution, cyclodextrin solution, polyethylene glycol solution and polyvinyl alcohol solution.
The liquid organic is preferably one or more of alcohols, ketones, ethers, acids, esters, phenols, amines and aldehydes.
In S2, the carbon coating temperature may be 500 ℃ to 700 ℃, preferably 500 ℃ to 630 ℃, more preferably 550 ℃ to 620 ℃, for example 600 ℃ or 620 ℃.
In S2, the carbon coating may be performed in an inert atmosphere; the gas of the inert atmosphere is preferably nitrogen and/or argon. Due to the fluidity of the gas, the integrity of the carbon coating is more complete than that of the carbon coating structure by the traditional solid phase method. When the used carbon source is a gaseous carbon source, the cracking or carbonization temperature is lower than the formation temperature of lithium ferrite, so that the temperature during carbon coating can be reduced, and carbon thermal reduction reaction of lithium ferrite and the carbon source at high temperature is avoided, wherein iron element can be reduced into elemental iron, lithium element can be reduced into lithium carbonate and gaseous lithium, and the lithium-iron ratio is damaged, so that the production of impurity phases is caused; the purity of the material can also be improved. The traditional solid-phase sintering method or in-situ high-temperature solid-phase method needs to add excessive lithium to compensate lithium consumed by carbothermic reduction, the mode is generally uncontrollable, the generation of a hetero-phase is easy to occur, the lithium ferrite is coated by carbon under the long-time high-temperature condition or the lithium ferrite is caused to agglomerate, the agglomeration is serious, a tiny and uniform sample is difficult to obtain, and the uniform dispersion is unfavorable when the sample is used as a lithium supplementing agent.
In S2, the carbon coating time may be 1h-4h, preferably 1.5h-3h, for example 1.5h or 3h.
In S2, after the carbon coating, the crushing treatment is not required again.
The fineness and uniformity of the powder can be further reduced by performing the air-stream crushing treatment after sintering is completed. The traditional sintering needs to be subjected to airflow crushing treatment, and due to the long-time sintering at high temperature, the materials are seriously agglomerated and agglomerated (the agglomeration severity is that a liquid-liquid system is more than a solid-solid system, and the corresponding reaction activity sequence is that the liquid-liquid system is more than the solid-solid system), so that the airflow crushing equipment is difficult to effectively crush, and even if the crushing is finished, the carbon coating structure is partially damaged, the integrity of the carbon coating is influenced, and the materials are enabled to be in contact with air, moisture and carbon dioxide to deteriorate. The preparation method can effectively avoid caking in the sintering process, does not need to carry out additional crushing, and can ensure that the prepared lithium ferrite material has a complete carbon coating structure.
In the present invention, the mass ratio of the carbon source to the product I may be 2 to 30:100, preferably 5-15:100, e.g., 5:100.
When the carbon source is a gaseous carbon source, the mass ratio of the carbon source to the product I may be 2-20:100, e.g., 5:100.
When the carbon source is an aqueous organic solution, the mass ratio of the carbon source to the product I may be 5-30:100, for example 5:100.
When the carbon source is a liquid organic, the mass ratio of the carbon source to the product I may be 5-30:100, for example 5:100.
The invention also provides a lithium ferrite material prepared by adopting the preparation method.
In the invention, the lithium ferrite material D 10 May be > 0.3 μm.
In the invention, the D of the lithium ferrite material 50 May be > 0.8 μm, preferably > 2.0 μm.
In the invention, the D of the lithium ferrite material 90 May be < 6.0 μm.
In the invention, the molar ratio of the lithium element to the iron element of the lithium ferrite material can be 5-7:1, preferably 5-6:1, for example 5.2:1, 5.3:1 or 5.4:1.
The invention also provides an application of the lithium ferrite material in a lithium ion battery anode material as a lithium supplementing agent.
On the basis of conforming to the common knowledge in the field, the above preferred conditions can be arbitrarily combined to obtain the preferred examples of the invention.
The reagents and materials used in the present invention are commercially available.
The invention has the positive progress effects that:
the lithium ferrite material prepared by the preparation method provided by the invention has a complete carbon coating structure, has smaller fineness, and has good specific capacity and cycle performance when used as a lithium supplementing agent of an electrode material.
Drawings
FIG. 1 is a TEM image of a lithium ferrite material prepared according to example 1 of the present invention.
FIG. 2 is a TEM image of the lithium ferrite material obtained in example 1 of the present invention.
FIG. 3 is an XRD spectrum of a lithium ferrite material prepared in example 1 of the present invention.
Detailed Description
The invention is further illustrated by means of the following examples, which are not intended to limit the scope of the invention. The experimental methods, in which specific conditions are not noted in the following examples, were selected according to conventional methods and conditions, or according to the commercial specifications.
Example 1
(1) Preparing a lithium ferrite precursor: according to the mole ratio of the lithium element to the iron element of 5.5:1, the following components are mixed1.687 kg of ferric nitrate (purity 99.5%) and 2.578kg of lithium carbonate (purity 99.5%) are fully ground and mixed uniformly in 10.5L water, so that D 90 Less than 150nm to obtain aqueous solution of lithium ferrite precursor, spray drying at 130deg.C, and air-stream crushing to obtain D 10 ＞0.3μm，D 50 ＞0.8μm-2.0μm，D 90 Lithium ferrite precursors of < 6.0 μm; the pressure of the airflow breaking is 6MPa; the frequency of the airflow disruption is 80Hz;
(2) Sintering the lithium ferrite precursor prepared in the step (1) in the air atmosphere of a fluidized bed at 850 ℃ for 30 hours to obtain a product I;
(3) The obtained product I reacts for 3 hours in nitrogen atmosphere at 600 ℃ to carry out carbon coating, and then the lithium ferrite material is obtained; wherein the carbon source is CH 4 The addition amount of the carbon source is 5wt% of the mass of the lithium ferrite precursor.
The lithium ferrite material prepared by the embodiment has a carbon coating structure, wherein the carbon content is 1-3%, only the crystal form of the lithium ferrite is produced, no impurity phase is generated, and the particle size distribution is D 10 ＞0.3μm，D 50 ＞0.8μm-2.0μm，D 90 ＜6.0μm。
The preparation methods of examples 2-7 and comparative examples 1 and 7-11 are the same as example 1, and the preparation process of comparative examples 2-6 adopts a mode of sintering, carbon coating and air current crushing, and the technological parameters are shown in tables 1-2. The amounts of the respective substances of examples 1 to 7 and comparative examples 1 to 11 to be fed are shown in Table 1.
TABLE 1
Specific process parameter settings are shown in table 2 (conditions not listed, i.e., same as in example 1):
TABLE 2
Effect examples
1. Lithium iron ratio test method
The elemental analyzer test (ICP-AES) was used, with the specific test steps: weighing 0.1g of lithium ferrite sample, carrying out microwave digestion by using 6mL of aqua regia, fixing the volume to 100mL, diluting by 100 times, testing the content of lithium and iron by adopting a standard curve method, wherein the model of ICP equipment is ICAP PRO, and the manufacturer is Siemens.
2. Specific charge capacity
The specific preparation method of the button cell comprises the following steps:
1) Manufacturing of positive plate
Dissolving lithium ferrite, conductive carbon black and polyvinylidene fluoride in NMP solution according to the mass ratio of 8:1:1, stirring for 3 hours in a vacuum stirrer, and controlling the solid content of the slurry to be 50%, thus preparing the anode slurry. The positive electrode slurry is uniformly coated on aluminum foil, then placed in a vacuum drying oven for drying at 120 ℃ for 12 hours, and after drying, the positive electrode slurry is punched into a wafer with the diameter of 12mm to be used as a positive electrode plate.
2) Lithium ion battery fabrication
Adopts a metal lithium sheet as a negative electrode, celgard 2400 microporous membrane as a diaphragm, and 1.0 mol/L LiPF 6 The solution is used as electrolyte, and the solvent of the electrolyte is prepared by mixing Ethylene Carbonate (EC), diethyl carbonate (DEC) and methyl ethyl carbonate (EMC) in a volume ratio of 1:1:1. And assembling the positive plate, the negative plate, the diaphragm and the electrolyte into a CR2016 type button cell in a glove box filled with argon, and testing the electrical property of the lithium ion battery. During testing, the cut-off voltage of the charging process is 4.2V, and the cut-off voltage of the discharging process is 2.0V.
3) And (3) charging to 4.5V by constant current corresponding to 0.05C, converting constant voltage charging to 0.02C, discharging to 2.0V by constant current corresponding to 0.05C, and taking the specific charge capacity of 0.05C as a test result.
3. Cycle performance
Preparation of a test cell:
1) Manufacturing of positive plate
94g of lithium iron phosphate, 3.06g of the lithium ferrite material prepared in the example or the comparative example, 4g of binder polyvinylidene fluoride (PVDF) and 4g of conductive agent acetylene black are respectively added into 80g of N-methylpyrrolidone to prepare uniform positive electrode slurry, the uniform positive electrode slurry is coated on two sides of an aluminum foil with the thickness of 16 mu m, and then the aluminum foil is dried at 120 ℃, rolled and cut to prepare a positive electrode plate with the thickness of 540 x 43.5 mm, wherein the weight of the active substance lithium iron phosphate is about 6.4g.
Preparation of negative electrode
94g of negative active ingredient natural graphite, 1.4g of CMC and 2g of conductive carbon black are added into 125g of deionized water, 1.6g of SBR is added to prepare uniform negative slurry, the uniform negative slurry is coated on two sides of copper foil with the thickness of 8 mu m, the copper foil is dried at 90 ℃, rolled and cut to prepare a negative plate with the size of 400 x 44mm, and the natural graphite active material contains 3.6g.
2) Assembly of a battery
Winding the positive and negative electrodes and polyethylene film into square lithium ion battery core, respectively, and then winding lithium hexafluorophosphate (LiPF 6 ) The electrolyte was dissolved in a mixed solvent of EC/EMC/dec=1:1:1 at a concentration of 1 mol/liter, and injected into a battery aluminum case in an amount of 3.25g/Ah, and sealed, to prepare a lithium ion secondary battery.
3) Battery performance test
Test conditions: constant-current and constant-voltage charging is carried out at 1C in a 50 ℃ incubator, the cut-off voltage is 4.5V, the incubator is left for 30 seconds, the current of 1C is discharged from 4.5V to 2.0V, and the initial charge-discharge capacity (1C) and the capacity retention rate after 300 circles (1C) of the incubator are circularly tested. The model of the test equipment is 5V12A, and the manufacturer is New Will electronic Limited company.
The capacity retention of 300 cycles measured under the same conditions of the battery without the lithium ferrite lithium supplement was 93.17%.
The test results are shown in Table 3.
TABLE 3 Table 3
The preparation method can ensure the stability of the lithium-iron ratio in the reaction process, avoid volatilization of lithium to a certain extent, ensure generation of lithium ferrite and avoid generation of impurity phases to influence the effect in the subsequent application process. The lithium ferrite material prepared by the method has a complete carbon coating structure, has smaller fineness, and has good specific capacity and cycle performance when used as a lithium supplementing agent of an electrode material.
The lithium ferrite material prepared in the embodiments 1-7 has smaller fineness and complete carbon coating structure, and when the lithium ferrite material is used as a lithium supplementing agent, the specific capacity of a battery can reach 546mAh/g or more, and the capacity retention rate of 300 cycles can reach 94.97% or more.
Fig. 1 and fig. 2 are TEM images of lithium ferrite prepared by the present invention, and as can be seen from fig. 1, the fineness of the lithium ferrite material prepared by the present invention is smaller and the distribution is uniform, and as can be seen from fig. 2, the carbon coating structure is complete, and the stable exertion of the effect of the lithium ferrite material used as a lithium supplementing agent can be ensured.
FIG. 3 is an XRD spectrum of a lithium ferrite material prepared by the present invention. Compared with a standard spectrogram of lithium ferrite (PDF#37-1151), the lithium ferrite material prepared by the invention has a good crystal structure.
Comparative example 1 differs from the example mainly in that the sintering temperature is not within the scope of the present invention, at which temperature no lithium ferrite material can be produced.
The comparative examples 2 to 6 are different from the examples mainly in that the lithium ferrite material is prepared by sintering, carbon coating is performed, and then air stream crushing is performed. The fineness of the lithium ferrite material produced in this way is large, probably because the lithium ferrite particles fuse during sintering and are difficult to break into very small particles during subsequent air-stream breaking. When the lithium ferrite is used as a lithium supplementing agent, the specific capacity of the battery can be obviously reduced, and the specific capacity is probably caused by that the carbon coating on the surface of the material is destroyed by firstly coating carbon and then crushing by airflow, so that the lithium ferrite is deteriorated when contacting with air, moisture and carbon dioxide, and the performance of the lithium ferrite as the lithium supplementing agent is affected. And the lithium ferrite material prepared in the comparative example 6 is an agglomerate, is unevenly distributed, and has the carbon content which is seriously out of standard and reaches more than 10%, so that the effect exertion is seriously influenced.
Comparative examples 7 and 8 differ from examples in the gas flow rate in the sintering equipment, and comparative examples 9 and 10 differ from examples in the stirring speed in the sintering equipment. The lithium ferrite material plays a great role in lithium supplementing agent, and when the gas flow rate is too high or the rotating speed is too high, volatilization of lithium can be accelerated, so that generation of a hetero-phase is caused, and the specific capacity and the cycle performance of the battery are affected. If the gas flow rate is too small or the rotating speed is too small, the lithium ferrite precursor of the material cannot be guaranteed to flow sufficiently in the sintering process, the fusion degree of the obtained particles is large, and even the reaction cannot be carried out.
Comparative example 11 differs from example in that the lithium iron ratio is not within the scope of the present invention, and the hetero-phase ratio of the lithium ferrite material obtained is large, and the specific capacity of the battery is greatly affected when it is used as a lithium supplement.
While the foregoing is directed to embodiments of the present invention, other and further details of the invention may be had by the present invention, it should be understood that the foregoing description is merely illustrative of the present invention and that no limitations are intended to the scope of the invention, except insofar as modifications, equivalents, improvements or modifications are within the spirit and principles of the invention.

Claims (10)

1. The preparation method of the lithium ferrite material is characterized by comprising the following steps of:
s1, sintering a lithium ferrite precursor to obtain a product I;
the preparation method of the lithium ferrite precursor comprises the following steps: grinding an iron source and a lithium source in water, and then drying and crushing; the particle diameter after grinding is D 90 ＜150nm；
D of the lithium ferrite precursor 90 ＜6.0μm，D 10 ＞0.3μm；D 50 > 0.8 μm; the molar ratio of the lithium element to the iron element in the lithium ferrite precursor is 5.5-8.0:1; the sintering temperature is 800-1000 ℃; the lithium ferrite precursor flows in sintering equipment during sintering, and the gas flow rate in the sintering equipment is 10-30L/min; the sintering equipmentThe stirring speed of the mixture is 200-1500r/min;
s2, carrying out carbon coating on the product I and a carbon source to obtain the lithium ferrite material;
d of the lithium ferrite material 10 Is > 0.3 μm, D 50 Is > 0.8 μm, D 90 Is < 6.0 μm.
2. The method for preparing a lithium ferrite material according to claim 1, wherein the sintering temperature is 850-950 ℃;
and/or the sintering time is 10-40h;
and/or the gas flow rate in the sintering equipment is 12-20L/min;
and/or the stirring speed of the sintering equipment is 500-1200r/min;
and/or the sintering equipment is a fluidized bed and/or a rotary kiln;
and/or the gas atmosphere of the sintering is air and/or inert atmosphere.
3. The method for preparing a lithium ferrite material according to claim 1, wherein the molar ratio of lithium element to iron element in the lithium ferrite precursor is 5.5-7.0:1;
and/or, the lithium ferrite precursor comprises an iron source and a lithium source;
wherein the iron source is a water-soluble iron-containing compound or a non-water-soluble iron-containing compound;
wherein the lithium source is a water-soluble lithium-containing compound and an insoluble lithium-containing compound.
4. The method for preparing a lithium ferrite material according to claim 1, wherein the carbon source is a gaseous carbon source or a liquid carbon source;
wherein the gaseous carbon source is CH 4 And/or C 2 H 4 ；
Wherein the liquid carbon source is an organic matter aqueous solution or a liquid organic matter;
and/or the mass ratio of the carbon source to the product I is 2-30:100.
5. the method for preparing a lithium ferrite material according to claim 4, wherein the carbon source is a gaseous carbon source, and the mass ratio of the carbon source to the product I is 2-20:100;
or the carbon source is an organic matter aqueous solution, and the mass ratio of the carbon source to the product I is 5-30:100;
or the carbon source is a liquid organic matter, and the mass ratio of the carbon source to the product I is 5-30:100.
6. The method for preparing a lithium ferrite material according to claim 1, wherein the carbon-coated temperature is 500 ℃ to 700 ℃;
and/or the carbon coating time is 1h-4h;
and/or, the carbon coating is performed in an inert atmosphere.
7. A method of producing a lithium ferrite material according to claim 3, wherein the iron source is a soluble iron-containing compound and the lithium source is a soluble lithium-containing compound;
or, the iron source is a soluble iron-containing compound, and the lithium source is an insoluble lithium-containing compound;
or, the iron source is an insoluble iron-containing compound and the lithium source is a soluble lithium-containing compound.
8. The method for preparing a lithium ferrite material according to claim 1, wherein in step S1, the drying temperature is 120 ℃ to 180 ℃; the crushing mode is airflow crushing or mechanical crushing; the pressure of the airflow crushing is 5MPa-10MPa; the frequency of the airflow disruption is 70Hz-130Hz.
9. Lithium ferrite material, characterized in that it is produced by the production method according to any one of claims 1 to 8.
10. Use of the lithium ferrite material of claim 9 as a lithium-supplementing agent in a positive electrode material of a lithium ion battery.
CN202311560612.1A 2023-11-22 2023-11-22 Lithium ferrite material and preparation method and application thereof Active CN117263254B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202311560612.1A CN117263254B (en) 2023-11-22 2023-11-22 Lithium ferrite material and preparation method and application thereof

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202311560612.1A CN117263254B (en) 2023-11-22 2023-11-22 Lithium ferrite material and preparation method and application thereof

Publications (2)

Publication Number Publication Date
CN117263254A true CN117263254A (en) 2023-12-22
CN117263254B CN117263254B (en) 2024-02-09

Family

ID=89206702

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202311560612.1A Active CN117263254B (en) 2023-11-22 2023-11-22 Lithium ferrite material and preparation method and application thereof

Country Status (1)

Country Link
CN (1) CN117263254B (en)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110459748A (en) * 2019-08-20 2019-11-15 湖北融通高科先进材料有限公司 A kind of carbon coating ferrous acid lithium material and preparation method thereof
CN115911357A (en) * 2022-11-18 2023-04-04 湖北万润新能源科技股份有限公司 Preparation method and application of carbon-coated lithium ferrite material
CN115893503A (en) * 2022-11-24 2023-04-04 易善莉 Preparation method and application of carbon-coated lithium ferrite

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110459748A (en) * 2019-08-20 2019-11-15 湖北融通高科先进材料有限公司 A kind of carbon coating ferrous acid lithium material and preparation method thereof
CN115911357A (en) * 2022-11-18 2023-04-04 湖北万润新能源科技股份有限公司 Preparation method and application of carbon-coated lithium ferrite material
CN115893503A (en) * 2022-11-24 2023-04-04 易善莉 Preparation method and application of carbon-coated lithium ferrite

Also Published As

Publication number Publication date
CN117263254B (en) 2024-02-09

Similar Documents

Publication Publication Date Title
CN113571781B (en) Lithium ion battery anode lithium supplement additive, preparation method thereof and lithium ion battery
EP4057390A1 (en) Carbon-coated lithium-rich oxide composite material and preparation method therefor
CN112349905B (en) Double-coating modified lithium ion battery positive electrode material and preparation method thereof
CN101693532B (en) Method for preparing lithium ferrous phosphate
US20140106223A1 (en) METHODS FOR SURFACE COATING OF CATHODE MATERIAL LiNi0.5-XMn1.5MXO4 FOR LITHIUM-ION BATTERIES
CN112531158A (en) High-nickel ternary single crystal material and preparation method thereof
JP2007230784A (en) Manufacturing process of lithium-iron complex oxide
CN112645300A (en) Hard carbon negative electrode material, lithium ion battery and preparation method and application thereof
CN115043387B (en) Preparation method of ammonium ferromanganese phosphate, lithium ferromanganese phosphate and application thereof
CN114804056A (en) Carbon-coated high-capacity lithium manganese iron phosphate material and preparation method and application thereof
WO2024119727A1 (en) Positive electrode material and preparation method therefor, and lithium ion battery
CN111162271A (en) Multi-element anode material, preparation method thereof and lithium ion battery
CN114079086A (en) Positive electrode lithium supplement additive, positive electrode plate, preparation method of positive electrode plate and lithium ion battery
CN114649530A (en) Preparation method of nanometer lithium manganese iron phosphate material of vanadium-titanium doped composite carbon nanotube and nanometer lithium manganese iron phosphate material
CN116730317A (en) Preparation method of lithium iron phosphate
CN116986572A (en) Modified lithium iron manganese phosphate positive electrode material, preparation method thereof and lithium ion battery
CN110931763A (en) Lithium ion battery anode material and preparation method and application thereof
WO2023173775A1 (en) Modified lithium ion battery positive electrode material and preparation method therefor and application thereof
CN117263254B (en) Lithium ferrite material and preparation method and application thereof
CN113964314B (en) Method for modifying surface of lithium transition metal oxide positive electrode material
CN102874788A (en) Process for preparing lithium iron phosphate material with co-precipitation method
CN113130899A (en) Lithium iron phosphate composite material and preparation method thereof
CN108172830B (en) Positive electrode material, preparation method thereof and battery
CN114524467B (en) Preparation method of high-purity micron-sized spherical sodium-electricity material
WO2024103564A1 (en) Method for preparing high-rate single-crystal positive electrode material from gel mixture, and use thereof

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant