CN115207330A - Lithium-containing silicon-oxygen negative electrode material and manufacturing method thereof - Google Patents

Lithium-containing silicon-oxygen negative electrode material and manufacturing method thereof Download PDF

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CN115207330A
CN115207330A CN202211029760.6A CN202211029760A CN115207330A CN 115207330 A CN115207330 A CN 115207330A CN 202211029760 A CN202211029760 A CN 202211029760A CN 115207330 A CN115207330 A CN 115207330A
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lithium
silicon
compound
oxygen
boric acid
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侯孟炎
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Suzhou Peiwa Energy Technology 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
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/485—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of mixed oxides or hydroxides for inserting or intercalating light metals, e.g. LiTi2O4 or LiTi2OxFy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/362—Composites
    • H01M4/366—Composites as layered products
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/58—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
    • H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
    • H01M4/587—Carbonaceous material, e.g. graphite-intercalation compounds or CFx for inserting or intercalating light metals
    • 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 lithium-containing silicon-oxygen negative electrode material and a manufacturing method thereof, wherein the manufacturing method of the lithium-containing silicon-oxygen negative electrode material comprises the following steps: s1, carrying out carbon coating on a silicon-oxygen material by a lithium-containing silicon-oxygen negative electrode material in a mode of cracking a carbon source in a non-oxidizing atmosphere; s2, lithium intercalation is carried out on the silicon-oxygen material coated with carbon in the S1 through a hot lithium intercalation method or a liquid phase lithium intercalation method; and S3, treating the silicon-oxygen material embedded with lithium in the S2 by using boric acid or a compound of the boric acid and a lithium-containing compound. The carbon layer is coated on the surface of the silicon-oxygen negative electrode material, so that the electronic conductivity is improved; treating the silicon-oxygen material after lithium intercalation by boric acid or a compound of the boric acid and a lithium-containing compound to reduce Li y SiO x The surface of the material is alkaline, the stability of the material in water-based slurry is improved, and the surface of the material is alkaline in Li y SiO x Surface profile of materialTo Li 3 BO 3 Coating layer and/or Li 2 CO 3 ‑Li 3 BO 3 And a coating layer for improving ion conductivity.

Description

Lithium-containing silicon-oxygen negative electrode material and manufacturing method thereof
Technical Field
The invention relates to the field of battery manufacturing, in particular to a lithium-containing silicon-oxygen negative electrode material and a manufacturing method thereof.
Background
In the process of developing and producing batteries, elemental silicon is considered as an important candidate material for a next-generation lithium ion battery high-energy-density negative electrode material due to the high specific discharge capacity of the elemental silicon. However, although the silicon negative electrode has high capacity, the large volume change (300%) in the lithium extraction process of the silicon negative electrode brings great challenges to practical application. The silicon-oxygen material limits the volume change in the lithium extraction process to a certain extent due to the existence of inactive substances in the silicon-oxygen material, and can show more excellent cycle performance. However, the silicon oxide material has some problems in that the material consumes the electrolyte to generate a thick SEI (Solid electrolyte interface) when the electrolyte is directly contacted and subjected to an electrochemical reaction, and in addition, an inactive substance inside the material particle generates a substance that irreversibly releases lithium, such as lithium silicate and lithium oxide, thereby causing lithium ion loss in the battery. The presence of these two types of irreversible reactions limits the coulombic efficiency (typically < 80%) of the first charge-discharge of silica-containing materials to a large extent, much lower than the current mainstream graphite negative electrode materials (typically > 90%). Meanwhile, the bottleneck of application of the silicon oxide compound also includes low ionic conductivity, electronic conductivity, and the like.
In order to improve the electrochemical performance of the silicon-oxygen material, a plurality of modification modifications are carried out on the silicon-oxygen material: (1) In order to isolate the side reactions caused by the contact of the silicon oxide material with the electrolyte and to improve the electronic conductivity, carbon coating is generally performed on the surface layer of the silicon oxide compound. (2) To compensate for the irreversible lithium consumption that occurs during the production of lithium silicate, silicon oxygen cathode materials can be pre-doped with lithium to increase first coulombic efficiency, including pre-lithiation of silicon oxygen compound materials using chemical or electrochemical methods. Because the modified compound has low water resistance due to lithium modification, the material is usually in strong alkalinity in aqueous solution, and thus, in the coating process of the battery pole piece, the slurry of the lithium-silicon-containing compound is usually denatured due to the alkalinity of the material, and the coating effect of the pole piece is influenced.
Disclosure of Invention
In order to overcome the above disadvantages, the present invention aims to provide a lithium-containing silicon-oxygen negative electrode material and a manufacturing method thereof, wherein the lithium-containing silicon-oxygen negative electrode material has high electronic conductivity and high ionic conductivity, and can reduce the surface alkalinity of the material and improve the stability of the material in an aqueous slurry.
In order to achieve the purpose, the invention adopts the technical scheme that: a lithium-containing silicon-oxygen negative electrode material comprising active material particles, a method of producing the same, and a lithium-containing silicon-oxygen negative electrode materialThe active material particles comprise Li y SiO x (0<x≤2,0<y.ltoreq.3), and in at least a part of Li y SiO x A surface-coated carbon coating layer and an ion-conducting coating layer, the ion-conducting coating layer comprising Li 3 BO 3 Coating layer and/or Li 2 CO 3 -Li 3 BO 3 And (4) compounding a coating layer.
Preferably, the median particle diameter of the active substance particles is from 0.5 to 25 μm; the mass percentage of the carbon coating layer and the active substance particles is 0.1-10w.t.%; li y SiO x The content of lithium in the lithium-containing material is 0.5-20w.t.%.
Preferably, the median particle diameter of the active substance particles is from 2 to 20 μm; the mass percentage of the carbon coating layer and the active substance particles is 0.5-8 w.t%; li y SiO x The lithium content in the lithium-containing alloy is 2 to 15w.t.%.
Preferably, the active material particles have a median particle diameter of from 3 to 15 μm; the mass percent of the carbon coating layer and the active substance particles is 1-6 w.t.%; li y SiO x The lithium content in the product is 6-12w.t.%.
The invention also discloses a method for manufacturing the lithium-containing silicon-oxygen negative electrode material, which comprises the following steps:
s1, coating the silicon-oxygen material with carbon in a mode that a carbon source is cracked in a non-oxidizing atmosphere, and coating the surface of the silicon-oxygen negative electrode material with a carbon layer to improve the electronic conductivity of the material.
The carbon coating is carried out by pyrolysis of a carbon source in a non-oxidizing atmosphere, and at least comprises one of the following coating modes: (1) A carbon source which is in the form of gas at room temperature, such as methane, ethylene, acetylene, etc., cracking the hydrocarbon gas at high temperature in a non-oxidizing atmosphere; (2) Forming mixed gas by using hydrocarbon which exists in a liquid form at room temperature, such as toluene, xylene and other liquid hydrocarbon under the carrying of non-oxidizing gas, and cracking the hydrocarbon gas at high temperature under the non-oxidizing atmosphere; (3) The carbon source exists in a solid state at room temperature, such as various forms of asphalt (e.g., petroleum asphalt, coal asphalt), synthetic resins (e.g., epoxy resin, phenol resin), sugars (e.g., sucrose, glucose), high molecular polymers (e.g., polyethylene glycol, polyethylene, polyacrylonitrile), and the like. At the moment, the carbon source is firstly coated on the surface of the particles in a physical mode, and then the carbon source is subjected to pyrolysis and carbonization in a non-oxidizing atmosphere to prepare the carbon-coated material.
In the third mode, the pyrolysis temperature is 400-1300 ℃, preferably 600-900 ℃;
the mass ratio of the silicon-oxygen compound to the carbon source is 1.03-1:1;
the non-oxidizing atmosphere at least comprises one or a mixture of several of the following gases: nitrogen, argon, hydrogen.
By carbon coating, there is generally a completely or partially coated carbon layer on the surface of the silica material particles, the mass percentage of the carbon coating and the active material particles being 0.1 to 10w.t.%, preferably 0.5 to 8w.t.%, more preferably 1 to 6w.t.%.
S2, lithium intercalation is carried out on the silicon oxygen material coated with carbon in the S1 through a thermal lithium intercalation method or a liquid phase lithium intercalation method;
the lithium hot insertion method comprises the following steps: the lithium source is selected from lithium simple substance or compound, such as metal lithium, lithium hydroxide, lithium carbonate, lithium hydride, etc., lithium nitrate, lithium acetate, etc. Fully mixing and uniformly stirring lithium source and silicon oxide material powder in a non-oxidizing atmosphere; then the mixed material is heat treated, the treatment temperature is 300-1000 ℃, and the optimal treatment temperature is 400-800 ℃. The treatment is generally carried out under a non-oxidizing atmosphere. The non-oxidizing atmosphere here contains at least one of nitrogen, argon, hydrogen, or a mixture of several of them.
The liquid phase lithium intercalation method comprises the following steps: adding silica material, lithium source and electron transfer reagent into ether solvent, wherein the lithium source is metal lithium or metal lithium alloy. Under the action of electron transfer reagent, metal lithium can be dissolved in ether solvent and uniformly reacted with silicon oxide compound, and the system temperature is controlled and the system is continuously stirred until the metal lithium disappears. The ether solvent herein includes one or more of tetrahydrofuran, ethylene glycol dimethyl ether, methyl butyl ether, diethyl ether, and the like. The electron transfer agent comprises one or more of biphenyl, naphthalene, anthracene, phenanthrene, etc. The reaction temperature is controlled within the range of 40-140 ℃. The stirring is carried out under a non-oxidizing atmosphere and comprises at least one of nitrogen, argon and hydrogen or a mixture of the nitrogen, the argon and the hydrogen. The lithium-embedded material is then heat treated at a temperature of 300 to 1000 deg.C, preferably 400 to 800 deg.C. The treatment is generally carried out under a non-oxidizing atmosphere. The non-oxidizing atmosphere here contains at least one of nitrogen, argon, hydrogen, or a mixture of several of them.
And S3, treating the silicon-oxygen material embedded with lithium in the S2 by using a compound of boric acid and a lithium-containing compound or boric acid. The lithium-containing compound is selected from lithium carbonate or lithium hydroxide.
Preferably, in S3, the following steps are included:
s31, boric acid or a compound of boric acid and a lithium-containing compound is uniformly mixed with the silica material embedded with lithium in S2, wherein the mixing can be solid-phase ball milling of several kinds of powder, or the boric acid or the compound of boric acid and the lithium-containing compound is prepared into solution or dispersion liquid, then the silica compound embedded with lithium is added, and then the solvent or the dispersing agent is removed. Wherein the mole ratio of lithium carbonate/boric acid in the composite is a,0 & lt a & gt & lt 1 & gt, the mass ratio of the composite to the silicone compound after lithium intercalation is b,0 & lt b & lt 0.5 & gt, preferably 0 & lt b & lt 0.2 & gt;
and S32, carrying out heat treatment on the mixed material prepared in the S31 in a non-oxidizing atmosphere, wherein the treatment temperature is 200-800 ℃, and preferably 300-700 ℃. The treatment is generally carried out under a non-oxidizing atmosphere. The non-oxidizing atmosphere here contains at least one of nitrogen, argon, hydrogen, or a mixture of several of them.
By treating the silicon-oxygen material after lithium is embedded in S2 with boric acid or a compound of boric acid and a lithium-containing compound, the lithium-containing silicon-oxygen negative electrode material has the following advantages:
1) Reacting boric acid to remove residual active lithium-containing substances in the system after the step S2, and reducing the alkalinity of the material so as to improve the system stability when the electrode is prepared into homogenate;
2) Introduction of Li with high ion conductivity 3 BO 3 Coating layer or Li 3 BO 3 -Li 2 CO 3 And a coating layer for improving the ion conductivity of the negative electrode material.
The invention has the following beneficial effects:
1) The carbon layer is coated on the surface of the silicon-oxygen negative electrode material, so that the electronic conductivity is improved;
2) Treating the silicon-oxygen material after lithium intercalation by boric acid or a compound of the boric acid and a lithium-containing compound to reduce Li y SiO x The surface of the material is alkaline, the stability of the material in water-based slurry is improved, and the surface of the material is alkaline in Li y SiO x Formation of Li on the surface of the material 3 BO 3 Coating layer and/or Li 2 CO 3 -Li 3 BO 3 And a coating layer for improving ion conductivity.
Drawings
FIG. 1 is a TEM image of the material obtained in example 1 of the present invention.
Detailed Description
The following detailed description of the preferred embodiments of the present invention, taken in conjunction with the accompanying drawings, will make the advantages and features of the invention easier to understand by those skilled in the art, and thus will clearly and clearly define the scope of the invention.
Example 1
S1, taking a silicon oxide compound SiO with the median particle size of 6 mu m after crushing x (x = 1), introducing methane in an argon atmosphere to carry out carbon coating, and controlling the temperature to be 900 ℃ to obtain the carbon-coated silica compound. The mass fraction of the carbon coating layer compared to the siloxane compound before coating was 4.5w.t.% by controlling the deposition time.
And S2, mixing LiH powder with the mass fraction being 6% of that of the coated silicon oxide compound in an argon atmosphere, and uniformly stirring. The stirred powder was subsequently heat treated under argon atmosphere at a temperature of 700 ℃.
And S3, putting the treated powder into a mixed solution of boric acid and lithium carbonate (the solvent is water/ethanol = 2/1), controlling the molar ratio of the lithium carbonate to the boric acid to be 0.5, and controlling the mass of the boric acid and lithium carbonate compound to be equal to 8 w.t% of the mass of the silicon-oxygen compound powder. Stirring, filtering, removing solvent to obtainTreating the obtained compound for 1h at 600 ℃ in argon atmosphere, and cooling to obtain the target product Li-containing silicon-oxygen negative electrode material y SiO x 。
Referring to FIG. 1, it can be seen that Li partially formed on the surface of the material was observed by taking a transmission electron micrograph of the material obtained in this example 3 BO 3 -Li 2 CO 3 And (4) compounding a coating layer.
Example 2
S1, taking a silicon oxide compound SiO with the median particle size of 3 mu m after crushing x (x = 1), introducing methane in an argon atmosphere to carry out carbon coating, and controlling the temperature to be 600 ℃ to obtain the carbon-coated silica compound. The deposition time was controlled so that the mass fraction of the carbon coating layer was 3w.t.% compared to the amount of the silicon oxide compound before coating.
And S2, mixing LiH powder with the mass fraction being 9% of that of the coated silicon oxide compound in an argon atmosphere, and uniformly stirring. The stirred powder was subsequently heat treated under an argon atmosphere at a temperature of 400 ℃.
S3, putting the treated powder into a mixed solution of boric acid and lithium carbonate (the solvent is water/ethanol = 2/1), controlling the molar ratio of the lithium carbonate to the boric acid to be 0.1, stirring, filtering and removing the solvent, wherein the mass of the boric acid and lithium carbonate compound is equal to 5w.t.% of that of the silicon-oxygen compound powder, treating the obtained compound for 1h at 300 ℃ in an argon atmosphere, and cooling to obtain the target product, namely the lithium-containing silicon-oxygen negative electrode material Li y SiO x 。
Example 3
S1, taking a silicon oxide compound SiO with the median particle size of 15 mu m after crushing x (x = 1), introducing methane in an argon atmosphere to carry out carbon coating, and controlling the temperature to be 750 ℃ to obtain the carbon-coated silica compound. The deposition time was controlled so that the mass fraction of the carbon coating layer was 20w.t% as compared to that of the silicon-oxygen compound before coating.
And S2, mixing LiH powder which is equivalent to 12% of the coated silica compound by mass under an argon atmosphere, and uniformly stirring. The stirred powder was then heat treated under an argon atmosphere at a temperature of 700 ℃.
S3, adding the treated powder into boric acidAnd lithium carbonate (solvent water/ethanol = 2/1), the molar ratio of lithium carbonate to boric acid was controlled to 0.9, and the mass of the boric acid/lithium carbonate complex corresponded to 15w.t.% of the mass of the silicon oxide compound powder. Stirring, filtering, removing solvent, treating the obtained compound at 700 ℃ for 1h in argon atmosphere, and cooling to obtain the target product Li-containing silicon-oxygen negative electrode material y SiO x 。
Example 4
Compared with the embodiment 1, the coal pitch is selected as the carbon source in the embodiment 4, the silica compound powder and the pitch are uniformly mixed and then are subjected to heat treatment in the argon atmosphere, and the temperature is controlled to be 900 ℃ to obtain the carbon-coated silica compound. The mass fraction of the carbon coating layer to the silica compound before coating was 4.5 w.t% by controlling the mass of the mixed pitch.
The specific manufacturing method comprises the following steps:
s1, taking a silicon oxide compound SiO with the median particle size of 6 mu m after crushing x (x = 1), uniformly mixing the silicon oxide powder and the pitch, and then performing heat treatment in an argon atmosphere, wherein the temperature is controlled to be 900 ℃, so as to obtain the carbon-coated silicon oxide. The mass fraction of the carbon coating layer to the silica compound before coating was 4.5 w.t% by controlling the mass of the mixed pitch.
And S2, mixing LiH powder with the mass fraction being 6% of that of the coated silicon oxide compound in an argon atmosphere, and uniformly stirring. The stirred powder was subsequently heat treated under argon atmosphere at a temperature of 700 ℃.
S3, putting the treated powder into a mixed solution of boric acid and lithium carbonate (the solvent is water/ethanol = 2/1), controlling the molar ratio of the lithium carbonate to the boric acid to be 0.5, stirring, filtering and removing the solvent, wherein the mass of the boric acid and lithium carbonate compound is equal to 8w.t.% of the mass of the silicon-oxygen compound powder, treating the obtained compound for 1h at 600 ℃ in an argon atmosphere, and cooling to obtain the target product, namely the lithium-containing silicon-oxygen negative electrode material Li y SiO x 。
Example 5
In example 5, lithium intercalation was performed by a liquid phase lithium intercalation method, and silicon oxide particles coated with carbon were immersed in a solution in which lithium flakes and biphenyl were dissolved in tetrahydrofuran, as compared with example 1. The solution was obtained by dissolving biphenyl in Tetrahydrofuran (THF) at a concentration of 1mol/L and then adding metal lithium corresponding to 6% by mass of the silicon oxide powder.
The specific manufacturing method comprises the following steps:
s1, taking a silicon oxide compound SiO with the median particle size of 6 mu m after crushing x (x = 1), introducing methane in an argon atmosphere to carry out carbon coating, and controlling the temperature to be 900 ℃ to obtain the carbon-coated silica compound. The mass fraction of the carbon coating layer compared to the siloxane compound before coating was 4.5w.t.% by controlling the deposition time.
S2, dissolving biphenyl in Tetrahydrofuran (THF) at a concentration of 1mol/L, adding metal lithium accounting for 6% of silicon oxide powder in mass into the solution, controlling the system temperature to be 100 ℃, continuously stirring the system until the metal lithium is dissolved in the THF solution, soaking silicon oxide particles coated with carbon into a solution formed by dissolving lithium sheets and biphenyl in the THF, and carrying out heat treatment on the material embedded with lithium at a treatment temperature of 700 ℃ in a non-oxidizing atmosphere.
And S3, putting the treated powder into a mixed solution of boric acid and lithium carbonate (the solvent is water/ethanol = 2/1), controlling the molar ratio of the lithium carbonate to the boric acid to be 0.5, and controlling the mass of the boric acid and lithium carbonate compound to be equal to 8w.t% of the mass of the silicon-oxygen compound powder. Stirring, filtering, removing solvent, treating the obtained compound for 1h at 600 ℃ in argon atmosphere, and cooling to obtain the target product Li-containing silicon-oxygen cathode material y SiO x 。
Example 6
In example 6, in comparison with example 1, in the mixed solution of boric acid and lithium carbonate (the solvent is water/ethanol = 2/1), the molar ratio of lithium carbonate and boric acid was controlled to 0.2, and the mass fraction of boric acid to the silicone oxide compound was 8%
The specific manufacturing method comprises the following steps:
s1, taking a silicon oxide compound SiO with the median particle size of 6 mu m after crushing x (x = 1), introducing methane in an argon atmosphere to carry out carbon coating, and controlling the temperature to be 900 ℃ to obtain the carbon-coated silica compound. By controlling the deposition timeThe mass fraction of the carbon coating layer compared to the silicone compound before coating was 4.5w.t.%.
And S2, mixing LiH powder which is 6 percent of the mass fraction of the silicon-coated compound under the argon atmosphere, and uniformly stirring. The stirred powder was subsequently heat treated under argon atmosphere at a temperature of 700 ℃.
And S3, putting the treated powder into a mixed solution of boric acid and lithium carbonate (the solvent is water/ethanol = 2/1), controlling the molar ratio of the lithium carbonate to the boric acid to be 0.2, and controlling the boric acid to be equal to 8 w.t% of the mass of the silicon-oxygen compound powder. Stirring, filtering, removing solvent, treating the obtained compound at 600 ℃ for 1h in argon atmosphere, and cooling to obtain the target product Li-containing silicon-oxygen negative electrode material y SiO x 。
Example 7
In example 7, in comparison with example 1, in the mixed solution of boric acid and lithium carbonate (the solvent is water/ethanol = 2/1), the molar ratio of lithium carbonate and boric acid was controlled to 0.8, and the mass fraction of boric acid to the silicone oxide compound was 8%
The specific manufacturing method comprises the following steps:
s1, taking a silicon oxide compound SiO with the median particle size of 6 mu m after crushing x (x = 1), introducing methane in an argon atmosphere to carry out carbon coating, and controlling the temperature to be 900 ℃ to obtain the carbon-coated silica compound. The mass fraction of the carbon coating layer compared to the siloxane compound before coating was 4.5w.t.% by controlling the deposition time.
And S2, mixing LiH powder which is 6 percent of the mass fraction of the silicon-coated compound under the argon atmosphere, and uniformly stirring. The stirred powder was subsequently heat treated under argon atmosphere at a temperature of 700 ℃.
And S3, putting the treated powder into a mixed solution of boric acid and lithium carbonate (the solvent is water/ethanol = 2/1), controlling the molar ratio of the lithium carbonate to the boric acid to be 0.8, and controlling the boric acid to be equivalent to 8 w.t% of the mass of the silicon oxide powder. Stirring, filtering, removing solvent, treating the obtained compound at 600 ℃ for 1h in argon atmosphere, and cooling to obtain the target product Li-containing silicon-oxygen negative electrode material y SiO x 。
Example 8
S1, taking a silicon oxide compound SiO with the median particle size of 6 mu m after crushing x (x = 1), introducing methane in an argon atmosphere to carry out carbon coating, and controlling the temperature to be 900 ℃ to obtain the carbon-coated silica compound. The mass fraction of the carbon coating layer compared to the siloxane compound before coating was 4.5w.t.% by controlling the deposition time.
And S2, mixing LiH powder which is 6 percent of the mass fraction of the silicon-coated compound under the argon atmosphere, and uniformly stirring. The stirred powder was then heat treated under an argon atmosphere at a temperature of 700 ℃.
And S3, putting the treated powder into a boric acid solution (the solvent is water/ethanol = 2/1), wherein the mass of boric acid is equivalent to 8w.t% of the mass of the silicon oxide powder. Stirring, filtering, removing solvent, treating the obtained compound for 1h at 600 ℃ in argon atmosphere, and cooling to obtain the target product Li-containing silicon-oxygen cathode material y SiO x 。
Example 9
S1, taking a silicon oxide compound SiO with the median particle size of 6 mu m after crushing x (x = 1), introducing methane in an argon atmosphere to carry out carbon coating, and controlling the temperature to be 900 ℃ to obtain the carbon-coated silica compound. The mass fraction of the carbon coating layer compared to the siloxane compound before coating was 4.5w.t.% by controlling the deposition time.
And S2, mixing LiH powder which is 6 percent of the mass fraction of the silicon-coated compound under the argon atmosphere, and uniformly stirring. The stirred powder was subsequently heat treated under argon atmosphere at a temperature of 700 ℃.
Example 10
The lithium-containing silicone materials prepared in examples 1 to 9 were used to prepare batteries, respectively, as follows.
The method for preparing the battery specifically comprises the following steps: graphite, the lithium-containing silica material prepared in any of examples 1 to 10, conductive additive 1 (carbon nanotubes, CNT), conductive additive 2 (conductive carbon black), and binder (polyacrylic acid, PAA) were mixed in a ratio of 80.75:14.25:0.1:1.5: and 3.4, mixing the components together by using water as a dispersing agent to prepare slurry. Coating the obtained slurry on a copper foil current collector, and sequentially drying and rollingAnd cutting to obtain the silicon-based negative pole piece. And assembling a button half cell in a glove box filled with argon, and taking a metal lithium sheet as a negative electrode. The electrolyte is 1M LiPF 6 in EC/DEC =3/7, 5% of FEC additive was added.
For a full cell, liNi is selected 0.7 Mn 0.2 Co 0.1 O 2 The material is a positive electrode material, liNi 0.7 Co 0.2 Mn 0.1 O 2 Carbon black SP/SWCNT/PVDF =96.4/1.5/0.1/2.4 negative pole piece, diaphragm (isolating positive and negative pole pieces, having micropore in the middle for transmitting lithium ion Li) + E.g., polyethylene or polypropylene film, etc.) and the positive electrode.
Meanwhile, a part of the obtained slurry is taken out for a slurry stability test, and the test process is as follows: and (3) storing the freshly prepared cathode slurry at room temperature (25 ℃), and observing the gas production condition of the cathode slurry.
Performance tests were performed on batteries prepared using the negative electrode materials prepared in examples 1-9, and the test data are shown in table 1.
Table 1: data of battery performance test prepared by negative electrode materials prepared in examples 1 to 9
Figure BDA0003815611040000111
As can be seen from the data tested in table 1, the stability of the material in the aqueous slurry is greatly improved by treating the lithium-intercalated silica material with boric acid or a complex of boric acid and lithium carbonate; the half-cell discharge capacity, the half-cell charge capacity, the first coulombic efficiency of the half-cell, the 100-cycle conservation rate and the rate capability of the full-cell are all improved.
Table 1 battery basic information description:
half cell: taking metal lithium as a negative electrode, wherein the voltage range is 0.005-1.5V, and the current density is 0.1C;
full cell: with LiNi 0.7 Mn 0.2 Co 0.1 The positive electrode is a positive electrode, the voltage range is 2.5-4.3V, the assembled battery is firstly circulated for 3 circles under the multiplying power of 0.05, and then the current density of the battery is circulatedIs 1C;
electrolyte 1M LiPF6 in EC/DEC =3/7, with 5% FEC additive;
wherein the SWCNT: a single-walled carbon nanotube; liPF 6 : lithium hexafluorophosphate; and (EC): ethylene carbonate; DEC: diethyl carbonate; FEC: fluoroethylene carbonate; PVDF: polyvinylidene fluoride.
The above embodiments are merely illustrative of the technical concept and features of the present invention, and the present invention is not limited thereto, and any equivalent changes or modifications made according to the spirit of the present invention should be included in the scope of the present invention.

Claims (10)

1. A lithium-containing silicon-oxygen negative electrode material is characterized by comprising active material particles, wherein the active material particles comprise Li y SiO x (0<x≤2,0<y.ltoreq.3), and in at least a part of Li y SiO x A surface-coated carbon coating layer and an ion-conducting coating layer, the ion-conducting coating layer comprising Li 3 BO 3 Coating layer and/or Li 2 CO 3 -Li 3 BO 3 And (4) compounding a coating layer.
2. The lithium-containing silicon oxygen negative electrode material as claimed in claim 1, wherein the active material particles have a median diameter of 0.5 to 25 μm; the mass percentage of the carbon coating layer and the active substance particles is 0.1-10w.t%; li y SiO x The mass percent of the lithium in the lithium battery is 0.5-20w.t.%.
3. The lithium-containing silicon oxygen negative electrode material as claimed in claim 1, wherein the median particle diameter of the active material particles is 2 to 20 μm; the mass percentage of the carbon coating layer and the active substance particles is 0.5-8 w.t%; li y SiO x The mass percent of lithium in the lithium battery is 2-15w.t.%.
4. The lithium-containing silicon-oxygen negative electrode material of claim 1, which is characterized in thatCharacterized in that the median particle diameter of the active substance particles is 3 to 15 μm; the mass percent of the carbon coating layer and the active substance particles is 1-6 w.t.%; li y SiO x The mass percent of lithium in the lithium alloy is 6-12w.t.%.
5. The method for manufacturing the lithium-containing silicon-oxygen negative electrode material is characterized by comprising the following steps of:
s1, carrying out carbon coating on a silica material in a mode of cracking a carbon source in a non-oxidizing atmosphere;
s2, lithium intercalation is carried out on the silicon-oxygen material coated with carbon in the S1 through a thermal lithium intercalation method or a liquid phase lithium intercalation method;
and S3, treating the silicon-oxygen material embedded with lithium in the S2 by using boric acid or a compound of the boric acid and a lithium-containing compound.
6. The method for manufacturing the lithium-containing silicon-oxygen negative electrode material as claimed in claim 5, wherein in S1, the mass ratio of the silicon-oxygen material to the carbon source is 1.
7. The method of claim 5, wherein in step S2, the lithium insertion method comprises the following steps: mixing a lithium source and a silica material in a non-oxidizing atmosphere, and then carrying out heat treatment on the mixed material, wherein the treatment temperature is 300-1000 ℃; the lithium source is selected from lithium simple substance or lithium-containing compound.
8. The method of claim 5, wherein the step of inserting lithium into the lithium-containing silicon-oxygen negative electrode material in S2 comprises the steps of:
s21, adding a silica material, a lithium source and an electron transfer reagent into an ether solvent, reacting at the temperature of 40-140 ℃, and stirring in a non-oxidizing atmosphere until the lithium source is dissolved in the ether solvent;
s22, carrying out heat treatment on the compound prepared in the S21, wherein the treatment temperature is 300-1000 ℃;
the lithium source is metal lithium or an alloy of the metal lithium;
the ether solvent is selected from one or more of tetrahydrofuran, ethylene glycol dimethyl ether, methyl butyl ether and diethyl ether;
the electron transfer reagent is selected from one or more of biphenyl, naphthalene, anthracene and phenanthrene.
9. The method for manufacturing a lithium-containing silicon oxygen negative electrode material according to claim 5, wherein the step S3 comprises the following steps:
s31, boric acid or a composite of boric acid and a lithium-containing compound and a silicon-oxygen material after lithium intercalation in S2 are uniformly mixed, wherein the mole ratio a,0 of the lithium-containing compound and the boric acid in the composite is formed by a yarn of cloth a and 1, and the mass ratio of the composite to the silicon-oxygen compound after lithium intercalation is b,0 yarn of cloth b and 0.5;
and S32, carrying out heat treatment on the mixed material prepared in the S31 in a non-oxidizing atmosphere, wherein the treatment temperature is 200-800 ℃.
10. The method of claim 9, wherein in S31, the lithium-embedded silicon-oxygen compound is mixed with boric acid or a composite of boric acid and a lithium-containing compound by any one of the following methods:
carrying out solid-phase ball milling on the powder of the silicon-oxygen compound embedded with lithium and boric acid or a compound of the boric acid and a lithium-containing compound;
preparing boric acid or a compound of the boric acid and a lithium-containing compound into solution or dispersion liquid, adding a silica compound after lithium insertion, and removing the solvent or the dispersing agent.
CN202211029760.6A 2022-08-25 2022-08-25 Lithium-containing silicon-oxygen negative electrode material and manufacturing method thereof Pending CN115207330A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116014145A (en) * 2023-03-28 2023-04-25 宁波杉杉新材料科技有限公司 Pre-lithiated silica composite material, preparation method and application thereof, pole piece containing pre-lithiated silica composite material and battery
CN117446807A (en) * 2023-11-14 2024-01-26 银硅(宁波)科技有限公司 Silicon oxide composite material by melt quenching method and preparation method and application thereof

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116014145A (en) * 2023-03-28 2023-04-25 宁波杉杉新材料科技有限公司 Pre-lithiated silica composite material, preparation method and application thereof, pole piece containing pre-lithiated silica composite material and battery
CN117446807A (en) * 2023-11-14 2024-01-26 银硅(宁波)科技有限公司 Silicon oxide composite material by melt quenching method and preparation method and application thereof

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