CN115986094A - Pre-lithiated silicon oxide negative electrode material with core-shell structure and preparation method and application thereof - Google Patents
Pre-lithiated silicon oxide negative electrode material with core-shell structure and preparation method and application thereof Download PDFInfo
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- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 title claims abstract description 163
- 229910052814 silicon oxide Inorganic materials 0.000 title claims abstract description 97
- 239000007773 negative electrode material Substances 0.000 title claims abstract description 34
- 239000011258 core-shell material Substances 0.000 title claims abstract description 27
- 238000002360 preparation method Methods 0.000 title claims description 12
- LIVNPJMFVYWSIS-UHFFFAOYSA-N silicon monoxide Chemical compound [Si-]#[O+] LIVNPJMFVYWSIS-UHFFFAOYSA-N 0.000 claims abstract description 60
- 239000010410 layer Substances 0.000 claims abstract description 36
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 19
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 18
- 238000005253 cladding Methods 0.000 claims abstract description 10
- 239000011248 coating agent Substances 0.000 claims description 26
- 238000000576 coating method Methods 0.000 claims description 26
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 20
- 238000000034 method Methods 0.000 claims description 19
- 238000006138 lithiation reaction Methods 0.000 claims description 15
- 239000002245 particle Substances 0.000 claims description 15
- 238000007740 vapor deposition Methods 0.000 claims description 15
- 229910052744 lithium Inorganic materials 0.000 claims description 13
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims description 12
- 229910052786 argon Inorganic materials 0.000 claims description 10
- 238000002156 mixing Methods 0.000 claims description 10
- WMFOQBRAJBCJND-UHFFFAOYSA-M Lithium hydroxide Chemical compound [Li+].[OH-] WMFOQBRAJBCJND-UHFFFAOYSA-M 0.000 claims description 9
- 150000001875 compounds Chemical class 0.000 claims description 9
- 238000010438 heat treatment Methods 0.000 claims description 9
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 claims description 8
- 229910001416 lithium ion Inorganic materials 0.000 claims description 8
- HSFWRNGVRCDJHI-UHFFFAOYSA-N alpha-acetylene Natural products C#C HSFWRNGVRCDJHI-UHFFFAOYSA-N 0.000 claims description 6
- 125000002534 ethynyl group Chemical group [H]C#C* 0.000 claims description 6
- 239000001307 helium Substances 0.000 claims description 6
- 229910052734 helium Inorganic materials 0.000 claims description 6
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 claims description 6
- XGZVUEUWXADBQD-UHFFFAOYSA-L lithium carbonate Chemical compound [Li+].[Li+].[O-]C([O-])=O XGZVUEUWXADBQD-UHFFFAOYSA-L 0.000 claims description 6
- 229910052808 lithium carbonate Inorganic materials 0.000 claims description 6
- KWGKDLIKAYFUFQ-UHFFFAOYSA-M lithium chloride Chemical compound [Li+].[Cl-] KWGKDLIKAYFUFQ-UHFFFAOYSA-M 0.000 claims description 6
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims description 6
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- 239000005977 Ethylene Substances 0.000 claims description 4
- XIXADJRWDQXREU-UHFFFAOYSA-M lithium acetate Chemical compound [Li+].CC([O-])=O XIXADJRWDQXREU-UHFFFAOYSA-M 0.000 claims description 3
- FUJCRWPEOMXPAD-UHFFFAOYSA-N lithium oxide Chemical compound [Li+].[Li+].[O-2] FUJCRWPEOMXPAD-UHFFFAOYSA-N 0.000 claims description 3
- 229910001947 lithium oxide Inorganic materials 0.000 claims description 3
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 claims description 3
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- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- BPQQTUXANYXVAA-UHFFFAOYSA-N Orthosilicate Chemical compound [O-][Si]([O-])([O-])[O-] BPQQTUXANYXVAA-UHFFFAOYSA-N 0.000 description 1
- 229910004283 SiO 4 Inorganic materials 0.000 description 1
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- 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 provides a pre-lithiated silicon monoxide negative electrode material with a core-shell structure, which sequentially comprises the following components from inside to outside: a prelithiated silica inner core, a silica cladding layer, and an amorphous carbon cladding layer. In the pre-lithiated silicon oxide negative electrode material with the core-shell structure, the pre-lithiated silicon oxide inner core can improve the first charge-discharge efficiency of the battery and the cycle performance of the battery. The intermediate layer silicon oxide coating layer can coat the pre-lithiated silicon oxide material with high surface alkali residue content, so that the surface alkali residue content of the material is reduced, and the processing performance and the cycle performance are improved. The amorphous conductive carbon on the outermost layer can improve the conductivity of the silicon oxide negative electrode material and solve the problem of poor conductivity of the silicon oxide negative electrode material.
Description
Technical Field
The invention belongs to the technical field of lithium ion batteries, and particularly relates to a prelithiation silicon monoxide negative electrode material with a core-shell structure, and a preparation method and application thereof.
Background
In the current lithium ion battery industry, the main material of the negative electrode is mainly graphite, however, the theoretical gram capacity of graphite is lower (372 mAh/g), so that the further improvement of the energy density of the lithium ion battery is limited. Silica is widely concerned due to its high gram capacity (2600 mAh/g), but the practical application of silica is severely limited due to its low first coulombic efficiency caused by the irreversible silicate formation during the first cycle and the high system expansion effect of the material itself.
The material prelithiation is one of the methods for solving the problem of low coulombic efficiency of the silicon monoxide. However, after the material is pre-lithiated, residual alkali is easy to exist on the surface of the material, and the pH value on the surface of the material is increased, so that the processing performance and the cycle performance of the pre-lithiated silicon oxide material are influenced.
The surface coating after the material is pre-lithiated is one of the methods for improving the processing performance and the gas generation tendency of the material. No. CN112701267B discloses an inner Li layer 2 SiO 3 Intermediate layer Li 2 Si 2 O 5 And the outermost layer is of a composite structure of a carbon layer, so that the pH value of the surface of the material is reduced, and the processing performance and the cycle performance of the material are improved. However, the material is pre-lithiated by adopting organic lithium salt, and the pre-lithiation condition has high requirement, toxicity and high cost.
The pre-lithiated silicon oxide/carbon composite material prepared by CN202011192614.6 can improve the first charge-discharge efficiency and the cycle performance of silicon oxide, but cannot improve the defects of poor processing performance and cycle easiness in gas generation caused by high residual alkali on the surface of the material.
Disclosure of Invention
In view of the above, the technical problem to be solved by the present invention is to provide a pre-lithiated silicon monoxide negative electrode material with a core-shell structure, and a preparation method and an application thereof.
The invention provides a pre-lithiated silicon monoxide negative electrode material with a core-shell structure, which sequentially comprises the following components from inside to outside: a prelithiated silica inner core, a silica cladding layer, and an amorphous carbon cladding layer.
The invention also provides a preparation method of the pre-lithiated silicon monoxide negative electrode material, which comprises the following steps:
a) Carrying out pre-lithiation treatment on the silicon oxide to obtain a pre-lithiated silicon oxide inner core;
b) Coating a layer of silicon oxide layer on the surface of the pre-lithiated silicon oxide inner core to obtain a silicon oxide coating layer;
c) And coating an amorphous carbon layer on the surface of the silicon oxide coating layer to obtain the amorphous carbon coating layer.
Preferably, step a) is:
and mixing the silicon monoxide with a lithium source compound, and carrying out pre-lithiation under the inert atmosphere condition to obtain a pre-lithiated silicon monoxide core.
Preferably, the pre-lithiated silica core has a particle size of from 2 μm to 25 μm.
The lithium source compound is selected from one or more of lithium carbonate, lithium acetate, lithium oxide, lithium chloride and lithium hydroxide.
The mass ratio of the silicon monoxide to the lithium source compound is 1-50: 1.
the inert atmosphere condition is selected from helium or argon.
The temperature of the prelithiation is 200-1000 ℃; the time of the pre-lithiation is 2 to 24 hours.
Preferably, step B) is:
and mixing the silicon oxide with the pre-lithiated silicon oxide inner core, carrying out heat treatment under the inert atmosphere condition, and coating a silicon oxide layer on the surface of the pre-lithiated silicon oxide inner core to obtain a silicon oxide coating layer.
Preferably, the particle size of the silica in the silica coating layer is 20 to 500nm.
The mass ratio of the silicon monoxide to the pre-lithiated silicon monoxide inner core is 1.
The inert atmosphere condition is selected from helium or argon.
The temperature of the heat treatment is 200-600 ℃, and the time of the heat treatment is 1-20 h.
Preferably, step C) is:
and coating an amorphous carbon layer on the surface of the silicon oxide coating layer by adopting a vapor deposition method to obtain the amorphous carbon coating layer.
Preferably, the carbon source used for vapor deposition is selected from one or more of acetylene, methane, ethylene and propylene; the thickness of the carbon coating layer is 5-50 nm.
The pyrolysis temperature of the vapor deposition is 300-1000 ℃; the time of the vapor deposition is 1 to 10 hours.
The invention also provides a negative pole piece which comprises the pre-lithiated silicon oxide negative pole material with the core-shell structure or the pre-lithiated silicon oxide negative pole material with the core-shell structure prepared by the preparation method.
The invention also provides a lithium ion battery which comprises the negative pole piece.
Compared with the prior art, the invention provides a pre-lithiated silicon oxide negative electrode material with a core-shell structure, which sequentially comprises the following components from inside to outside: a prelithiated silica inner core, a silica cladding layer, and an amorphous carbon cladding layer. In the pre-lithiated silicon oxide negative electrode material with the core-shell structure, the pre-lithiated silicon oxide inner core can improve the first charge-discharge efficiency of the battery and the cycle performance of the battery. The intermediate layer silicon oxide coating layer can coat the pre-lithiated silicon oxide material with high surface residual alkali content, so that the residual alkali content of the material surface is reduced, and the processing performance and the cycle performance are improved. The amorphous conductive carbon on the outermost layer can improve the conductivity of the silicon oxide negative electrode material and solve the problem of poor conductivity of the silicon oxide negative electrode material.
Drawings
FIG. 1 is an SEM image of a prelithiated silica material having a core-shell structure prepared in example 1.
Detailed Description
The invention provides a pre-lithiated silicon monoxide negative electrode material with a core-shell structure, which sequentially comprises the following components from inside to outside: a prelithiated silica inner core, a silica cladding layer, and an amorphous carbon cladding layer.
The pre-lithiated silicon oxide negative electrode material with the core-shell structure comprises a pre-lithiated silicon oxide inner core, wherein the particle size of the pre-lithiated silicon oxide inner core is 2-25 mu m.
After prelithiation of the material, oxidation of the silicon to form Li with lithium 2 O and Li 4 SiO 4 The silicon oxide serving as a good in-situ buffer matrix effectively relieves the volume effect of active ingredients in the charging and discharging process, and improves the first charging and discharging efficiency and the cycle performance of the silicon oxide.
The pre-lithiation silicon oxide negative electrode material with the core-shell structure further comprises a silicon oxide coating layer coated on the outer surface of the pre-lithiation silicon oxide inner core, wherein the thickness of the silicon oxide coating layer is 0.1-1 mu m, and the particle size of silicon oxide in the silicon oxide coating layer is 20-500 nm, preferably 50-200 nm.
The pre-lithiated silicon oxide negative electrode material with the core-shell structure further comprises an amorphous carbon coating layer coated on the surface of the silicon oxide coating layer. The thickness of the amorphous carbon coating layer is 5-50 nm.
The method reduces the residual alkali amount on the surface of the pre-lithiated silicon oxide, increases the processing performance of the pre-lithiated silicon oxide, reduces gas generation in the circulating process, improves the circulating performance of the pre-lithiated silicon oxide negative electrode material, and plays an important role in the application of the pre-lithiated silicon oxide negative electrode material.
The invention also provides a preparation method of the pre-lithiated silicon monoxide negative electrode material, which comprises the following steps:
a) Carrying out pre-lithiation treatment on the silicon oxide to obtain a pre-lithiated silicon oxide inner core;
b) Coating a layer of silicon oxide layer on the surface of the pre-lithiated silicon oxide inner core to obtain a silicon oxide coating layer;
c) And coating an amorphous carbon layer on the surface of the silicon oxide coating layer to obtain the amorphous carbon coating layer.
The method comprises the steps of firstly carrying out pre-lithiation treatment on the silicon oxide to obtain a pre-lithiated silicon oxide inner core. Specifically, the pre-lithiated silica core is obtained by mixing the silica with a lithium source compound and carrying out pre-lithiation under an inert atmosphere condition.
Wherein the pre-lithiated silica core has a particle size of 2 to 25 μm, preferably 4 to 15 μm, and more preferably 4, 5, 8, 10, 12, 15, or any value between 4 and 15 μm.
The lithium source compound is selected from one or more of lithium carbonate, lithium acetate, lithium oxide, lithium chloride and lithium hydroxide.
The mass ratio of the silicon monoxide to the lithium source compound is (1-50): 1, preferably in a mass ratio of (5 to 20): 1, more preferably 5: any value between 1.
The inert atmosphere conditions are selected from helium or argon, preferably argon.
The temperature of the pre-lithiation is 200-1000 ℃, preferably 500-800 ℃, and further preferably 500, 600, 700, 800, or any value between 500-800 ℃; the time of the prelithiation is 2 to 24 hours, preferably 2 to 10 hours, and more preferably 2, 4, 6, 8, 10, or any value between 2 to 10 hours.
Then, coating a layer of silica layer on the surface of the pre-lithiated silica core to obtain a silica coating layer; specifically, the silicon oxide is mixed with the pre-lithiated silicon oxide inner core, heat treatment is carried out under the inert atmosphere condition, and a silicon oxide layer is coated on the surface of the pre-lithiated silicon oxide inner core.
Wherein the particle size of the silica in the silica coating layer is 20 to 500nm, preferably 50 to 200nm, and more preferably 50, 100, 150, 200, or any value between 50 and 200nm.
The mass ratio of the silica to the pre-lithiated silica core is 1:10 to 30, more preferably 1: any value between 10 and 30.
The inert atmosphere conditions are selected from helium or argon, preferably argon.
The temperature of the heat treatment is 200-600 ℃, preferably 300-500 ℃, and more preferably 300, 350, 400, 450, 500, or any value between 300-500 ℃; the time for the heat treatment is 1 to 20 hours, preferably 1 to 5 hours, and more preferably 1, 2, 3, 4, 5, or any value between 1 and 5 hours.
And finally, coating an amorphous carbon layer on the surface of the silicon oxide coating layer to obtain the amorphous carbon coating layer. Specifically, an amorphous carbon coating layer is coated on the surface of the silicon oxide coating layer by adopting a vapor deposition method.
Wherein, the carbon source used for vapor deposition is selected from one or more of acetylene, methane, ethylene and propylene, and acetylene is preferred.
The pyrolysis temperature of the vapor deposition is 300-1000 ℃, preferably 500-800 ℃, and more preferably 500, 600, 700, 800, or any value between 500-800 ℃; the time of the vapor deposition is 1 to 10 hours, preferably 2 to 5 hours, preferably 2, 3, 4, 5, or any value between 2 and 5 hours.
The silicon monoxide negative electrode material prepared by the method can reduce the residual alkali amount on the surface of the material, improve the processing performance of the material, and has high first coulombic efficiency and cycle performance.
The invention also provides a lithium ion battery negative electrode piece which comprises the pre-lithiated silicon oxide negative electrode material with the core-shell structure or the pre-lithiated silicon oxide negative electrode material with the core-shell structure prepared by the preparation method.
The invention also provides a lithium ion battery, which comprises a positive electrode, a negative electrode, a diaphragm and electrolyte, wherein the negative electrode is selected from the negative electrode pole piece of the lithium ion battery.
In the pre-lithiated silicon monoxide negative electrode with the core-shell structure, the silicon monoxide with the pre-lithiated core can improve the first charge-discharge efficiency of the battery and the cycle performance of the battery. The intermediate layer monox coating layer can coat the prelithiated monox inner core with high surface residual alkali content, thereby reducing the residual alkali content on the material surface and improving the processing performance and the cycle performance. The outermost amorphous conductive carbon can improve the conductivity of the prelithiated silicon oxide negative electrode material and improve the problem of poor conductivity of the silicon oxide negative electrode material.
For further understanding of the present invention, the prelithiated silica negative electrode material with core-shell structure and the preparation method and application thereof provided by the present invention are described below with reference to the following examples, and the scope of the present invention is not limited by the following examples.
Example 1
1. The particle size of the silicon oxide is 5 mu m, the lithium salt is lithium carbonate, and the mass ratio of the silicon oxide to the lithium salt is 20:1, after uniformly mixing, carrying out pre-lithiation on the silicon monoxide in the atmosphere of inert gas argon at the temperature of 500 ℃ for 4 hours to obtain a pre-lithiated silicon monoxide kernel.
2. Carrying out silicon oxide coating on the product of the step 1
Uniformly mixing the silicon oxide with the particle size of 50nm and the pre-lithiated silicon oxide inner core according to the mass ratio of 1.
3. Carbon coating the product of step 2
The coating adopts a vapor deposition method, acetylene is used as a carbon source, the pyrolysis temperature is 700 ℃, and the time is 2 hours.
The pre-lithiated silicon oxide negative electrode material with the core-shell structure is obtained through the steps. Referring to fig. 1, fig. 1 is an SEM image of a pre-lithiated silica anode material having a core-shell structure prepared in example 1, and it can be seen from the figure that the material is spherical and has a secondary spherical shape consisting of a plurality of small particles. The material properties are shown in table 1.
Example 2
1. The particle size of the silicon oxide is 15 microns, the lithium salt is lithium carbonate, the mass ratio of the silicon oxide to the lithium salt is 12.
2. Carrying out silica coating on the product of the step 1:
uniformly mixing silicon oxide with the particle size of 100nm and the pre-lithiated silicon oxide inner core according to the mass ratio of 1.
3. And (3) carrying out carbon coating on the product of the step (2):
the coating adopts a vapor deposition method, the carbon source is ethylene, the pyrolysis temperature is 800 ℃, and the time is 1h.
The pre-lithiated silicon oxide negative electrode material with the core-shell structure is obtained through the steps. The material properties are shown in table 1.
Example 3
1. The particle size of the silicon monoxide is 10 mu m, the lithium salt is lithium carbonate, and the mass ratio of the silicon monoxide to the lithium salt is 15:1, after uniformly mixing, carrying out pre-lithiation on the silicon monoxide in the atmosphere of inert gas argon at the temperature of 500 ℃ for 5 hours to obtain a pre-lithiated silicon monoxide kernel.
2. Carrying out silica coating on the product of the step 1:
uniformly mixing silicon oxide with the particle size of 50nm and a pre-lithiated silicon oxide inner core according to the mass ratio of 1.
3. And (3) carrying out carbon coating on the product of the step (2):
the coating adopts a vapor deposition method, acetylene is used as a carbon source, the pyrolysis temperature is 700 ℃, and the time is 2 hours.
The pre-lithiated silicon oxide negative electrode material with the core-shell structure is obtained through the steps. The material properties are shown in table 1.
Comparative example 1
The difference from example 1 is that the coating with the silica and the coating with the carbon were not performed, and the specific properties are shown in Table 1.
Comparative example 2
The difference from example 2 is that no carbon coating is performed, and the specific properties are shown in table 1.
The materials prepared in the above examples and comparative examples were used for the preparation of batteries by the following specific method;
the electrical tapping test is carried out by using the silicon oxide negative electrode materials prepared by the embodiment group and the comparison group, the electrical tapping positive electrode is the prepared silicon oxide negative electrode material, and the formula is SiO: SP: CNT: PAA: SBR = 90; the negative electrode is a lithium sheet; diaphragm: 9 μmPE base film; the electrolyte is 1MLiPF 6 Dissolution in EC: DMC =1 in a solvent. The preparation method comprises the following steps: 1. uniformly coating the silicon monoxide material and other auxiliary materials on the surface of the copper foil, and cutting into wafers; 2. and uniformly placing the positive electrode/electrolyte/diaphragm/electrolyte/lithium sheet in the electric steel shell in sequence, and compacting.
The performance test method comprises the following steps:
(1) And (3) testing the pH value of the material: weighing the sample, accurately measuring to 0.1mg, adding deionized water, stirring, performing ultrasound for 10min, placing in a constant temperature water bath, maintaining the temperature to 25 deg.C, collecting supernatant, continuously testing with pH tester for three times, and collecting the average value.
(2) Gram capacity, first effect test method: voltage interval: 0.001V-2V. Charging and discharging current: and 0.1C, discharging firstly and then charging, wherein gram capacity is first charging capacity, and the first effect calculation method is first charging capacity/first discharging capacity.
(3) The cycle test method comprises the following steps: charging and discharging at a rate of 0.5C/0.5C, with a voltage interval of 0.001V-2V, and cycling for 200 cycles.
The obtained batteries were subjected to performance tests, and the results are shown in table 1.
Watch 1 Performance watch (electric buckle)
As can be seen from table 1, examples 1 to 3 all showed higher discharge capacity, first effect and capacity retention rate than the comparative example, and the pH value of the material surface was also greatly improved.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.
Claims (10)
1. A pre-lithiated silicon oxide negative electrode material with a core-shell structure is characterized by sequentially comprising the following components from inside to outside: a prelithiated silica inner core, a silica cladding layer, and an amorphous carbon cladding layer.
2. A method of making a prelithiated silicon oxide negative electrode material as claimed in claim 1, comprising the steps of:
a) Carrying out pre-lithiation treatment on the silicon oxide to obtain a pre-lithiated silicon oxide inner core;
b) Coating a layer of silicon oxide layer on the surface of the pre-lithiated silicon oxide inner core to obtain a silicon oxide coating layer;
c) And coating an amorphous carbon layer on the surface of the silicon oxide coating layer to obtain the amorphous carbon coating layer.
3. The method of claim 2, wherein step a) is:
and mixing the silicon monoxide with a lithium source compound, and carrying out pre-lithiation under the inert atmosphere condition to obtain a pre-lithiated silicon monoxide core.
4. The method of claim 3, wherein the pre-lithiated silica core has a particle size of 2 to 25 μm;
the lithium source compound is selected from one or more of lithium carbonate, lithium acetate, lithium oxide, lithium chloride and lithium hydroxide;
the mass ratio of the silicon monoxide to the lithium source compound is 1-50: 1;
the inert atmosphere condition is selected from helium or argon;
the temperature of the prelithiation is 200-1000 ℃; the time of the pre-lithiation is 2 to 24 hours.
5. The method of claim 2, wherein step B) is:
and mixing the silicon oxide with the pre-lithiated silicon oxide inner core, carrying out heat treatment under the condition of inert atmosphere, and coating a silicon oxide layer on the surface of the pre-lithiated silicon oxide inner core to obtain a silicon oxide coating layer.
6. The production method according to claim 5, wherein the particle size of the silica in the silica coating layer is 20 to 500nm;
the mass ratio of the silicon monoxide to the pre-lithiated silicon monoxide inner core is 1;
the inert atmosphere condition is selected from helium or argon;
the temperature of the heat treatment is 200-600 ℃; the time of the heat treatment is 1 to 20 hours.
7. The method of claim 2, wherein step C) is:
and coating an amorphous carbon layer on the surface of the silicon oxide coating layer by adopting a vapor deposition method to obtain the amorphous carbon coating layer.
8. The production method according to claim 7, wherein the carbon source for vapor deposition is selected from one or more of acetylene, methane, ethylene and propylene;
the thickness of the carbon coating layer is 5-50 nm;
the pyrolysis temperature of the vapor deposition is 300-1000 ℃; the time of the vapor deposition is 1 to 10 hours.
9. A negative pole piece is characterized by comprising the pre-lithiated silica negative pole material with the core-shell structure disclosed in claim 1 or the pre-lithiated silica negative pole material with the core-shell structure prepared by the preparation method disclosed in any one of claims 2 to 8.
10. A lithium ion battery comprising the negative electrode sheet of claim 9.
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