CN110690452A - Lithium battery negative electrode material with core-shell structure and lithium battery - Google Patents

Lithium battery negative electrode material with core-shell structure and lithium battery Download PDF

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CN110690452A
CN110690452A CN201910977656.1A CN201910977656A CN110690452A CN 110690452 A CN110690452 A CN 110690452A CN 201910977656 A CN201910977656 A CN 201910977656A CN 110690452 A CN110690452 A CN 110690452A
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negative electrode
silicon
lithium
carbon
electrode material
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罗飞
刘柏男
李泓
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Liyang Tianmu Pilot Battery Mstar Technology 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
    • H01M4/62—Selection of inactive substances as ingredients for active masses, e.g. binders, fillers
    • H01M4/628—Inhibitors, e.g. gassing inhibitors, corrosion inhibitors
    • 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
    • H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
    • H01M4/134—Electrodes based on metals, Si or alloys
    • 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
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/386—Silicon or alloys based on silicon
    • H—ELECTRICITY
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    • 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
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • 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
    • H01M2004/027—Negative electrodes
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    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
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Abstract

The embodiment of the invention relates to a lithium battery cathode material with a core-shell structure and a lithium battery, wherein the cathode material is a silicon-carbon composite material with a core-shell structure; the inner core of the negative electrode material is a composite material of silicon oxide or silicon alkene and a buffer material, and the shell is one or more coating layers or particle layers formed by carbon, carbon particles, carbon fibers or carbon nanotubes with a protection effect; the silicon oxide accounts for 5-95% of the mass ratio of the negative electrode material; the buffer material accounts for 1% -300% of the mass of the silicon oxide; the mass ratio of the shell to the anode material is 0.1-10%; in the Raman spectrum of the cathode material, the concentration is 475 +/-10 cm‑1With amorphous drumBags, and/or at 510 + -10 cm‑1Has a crystalline state peak; and is 1360 +/-20 cm‑1And 1580 +/-20 cm‑1With a characteristic peak for carbon.

Description

Lithium battery negative electrode material with core-shell structure and lithium battery
Technical Field
The invention relates to the technical field of batteries, in particular to a lithium battery cathode material with a core-shell structure and a lithium battery.
Background
The carbon-based negative electrode material is widely applied to the negative electrode material due to the advantages of excellent conductivity, lower working potential, smaller volume change of the lithium to be intercalated and deintercalated and the like, so that the high energy density and the long cycle life of the lithium battery are realized, and the commercialization is realized in 1991. However, the theoretical capacity of the carbon-based negative electrode material is only 372mAh/g, so that the further development of the carbon-based negative electrode material in the lithium ion battery is limited.
In order to achieve high specific capacity of the negative electrode, new negative electrode materials are continuously developed. The theoretical reversible capacity of silicon serving as a lithium ion battery negative electrode material is up to 4200mAh/g, but the volume change of the silicon material is large in the lithium desorption process, so that the problems of electrode material structure collapse, unstable Solid Electrolyte Interface (SEI) film and the like are caused, and the battery cyclicity is very poor. It was found that particle fracture During volume expansion is related to particle Size as demonstrated by in situ Transmission Electron Microscopy (TEM) as in the literature (X.H.Liu, L.Zong, S.Huang, S.X.Mao, T.Zhu, J.Y.Huang, Size-Dependent Fracteur of Silicon Nanoparticles dilution, ACS Nano,6(2012) 1522-. Therefore, the nano silicon material becomes a development direction of the silicon-based negative electrode material. Li et al, using nanoscale silicon particles to prepare negative electrode materials, have improved cycling performance and maintained high reversible capacity (1700mAh/g), as described in the literature (H.Li, X.J.Huang, L.Q.Chen, Z.G.Wu, Y Liang, electric chem.and solid-State Lett., 2, 547-Amp) 549 (1999)). But the first week coulombic efficiency of the nanoparticles is poor (65%) due to the agglomeration of the nanoparticles, and the nanoparticles are still not ideal as silicon-based anode material.
In addition to silicon nanocrystallization, silicon carbon composites have also become a potential development. CN106067547A discloses a preparation method of a silicon-carbon composite material, which comprises carbon-coating silicon particles, dispersing the silicon particles in graphene to form spherical particles, and coating a pyrolytic carbon layer on the surfaces of the spherical particles, wherein the structure provides a space for buffering the volume expansion of silicon, so as to reduce the overall expansion of the material, but does not fundamentally solve the problem of the expansion of silicon itself. The grapheme similar to graphene has the theoretical capacity of 954mAh/g, has sufficient space for absorbing and transferring Li ions, can prevent the structural fracture problem similar to crystalline silicon in the circulation process, and has small volume effect. But the first week coulombic efficiency was low due to the high specific surface area of the silylene.
Therefore, many problems still remain to be solved in the silicon-based anode material.
Disclosure of Invention
The invention aims to provide a negative electrode material for a lithium battery with a core-shell structure, wherein the negative electrode material has the core-shell structure, the problem caused by volume change in the charging and discharging processes of the battery is relieved through a shell coating layer or a particle layer, and the problem of low first-cycle coulombic efficiency caused by high specific surface area is solved, so that the silicon-carbon composite material has the advantages of long cycle and high stability, and the silicon oxide alkene material simultaneously ensures higher capacity and first-cycle coulombic efficiency.
In order to achieve the above object, in a first aspect, the present invention provides a negative electrode material for a lithium battery having a core-shell structure, where the negative electrode material is a silicon-carbon composite material having a core-shell structure;
the inner core of the negative electrode material is a composite material of silicon oxide or silicon alkene and a buffer material, and the shell is one or more coating layers or particle layers formed by carbon, carbon particles, carbon fibers or carbon nanotubes with a protection effect;
the silicon oxide accounts for 5-95% of the mass ratio of the negative electrode material;
the buffer material accounts for 1% -300% of the mass of the silicon oxide;
the mass ratio of the shell to the anode material is 0.1-10%;
in the Raman spectrum of the cathode material, the concentration is 475 +/-10 cm-1Has an amorphous bulge, and/or is within 510 + -10 cm-1Has a crystalline state peak; and is 1360 +/-20 cm-1And 1580 +/-20 cm-1A characteristic peak with carbon;
the negative electrode material still keeps a core-shell structure after the lithium battery is cycled, wherein the kernel is a composite material of lithium-deintercalated silicon oxide or silylene and a buffer material after the lithium battery is cycled, and the lithium-deintercalated silicon oxide or silylene is formed by compounding one or more of metal silicon, lithium silicon alloy, doped metal silicon, doped lithium silicon alloy, lithium silicate, lithium oxide, a compound silicic acid compound and a compound oxide; the shell is a composite material of a carbon coating layer and a solid electrolyte interface SEI film generated by a lithium battery cycling side reaction.
Preferably, the silicon oxide has the general formula SiAxOyX is greater than or equal to 0 and less than 10, and y is greater than 0 and less than 10;
the general formula of the silylene is SiAxX is 0 or more and less than 10;
wherein A is one or more of Be, B, P, N, Na, Mg, Al, Ti, Li, Mg, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Ga, Ge, Mo, Sn, Ag, Bi, Pb, Sb or Ba elements.
Preferably, the silicon oxide has a sheet structure, the thickness of the silicon oxide is 1-500nm, and the size of the silicon oxide is 10nm-10 μm; and at least one metal silicon phase is contained therein.
Preferably, the buffer material includes: one or a combination of more of carbon, carbon black, carbon nanotubes, natural graphite, artificial graphite, expanded graphite, microporous graphite, graphite flakes, nano metal particles or metal fibers, and is used for buffering the expansion and contraction of the material caused by the volume change of the silicon oxide or the silicon alkene material in the charging and discharging processes.
Preferably, the particle size of the buffer material is 10nm-20 microns, and the volume change of the buffer material in the lithium extraction process is not more than 50%.
Preferably, the mass specific capacity of the negative electrode material as the negative electrode material of the lithium ion battery is 400-2500 mAh/g.
In a second aspect, an embodiment of the present invention provides a negative electrode tab, including the negative electrode material described in the first aspect.
Preferably, the negative electrode plate is used for a lithium ion battery, a lithium ion capacitor, a lithium sulfur battery or an all-solid-state lithium battery.
In a third aspect, an embodiment of the present invention provides a lithium battery, including the negative electrode material described in the first aspect.
The lithium battery cathode material with the core-shell structure provided by the embodiment of the invention has the core-shell structure, the problem caused by volume change in the battery charging and discharging process is relieved through the shell coating layer or the particle layer, and the problem of low first-cycle coulombic efficiency caused by high specific surface area is improved, so that the silicon-carbon composite material has the advantages of long cycle and high stability, and the silicon oxide alkene material simultaneously ensures higher capacity and first-cycle coulombic efficiency.
Drawings
Fig. 1 is a partially enlarged view of a raman spectrum of a negative electrode material for a lithium battery provided in an embodiment of the present invention;
fig. 2 is a Scanning Electron Microscope (SEM) image of a negative electrode material for a lithium battery according to an embodiment of the present invention;
FIG. 3 is a graph showing the capacity fade of a negative electrode material for a lithium battery according to a comparative example of the present invention;
FIG. 4 is a Transmission Electron Microscope (TEM) image of a silylene oxide.
Detailed Description
The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.
The embodiment of the invention provides a negative electrode material with a core-shell structure for a lithium battery, wherein the negative electrode material is a silicon-carbon composite material with the core-shell structure;
the inner core of the cathode material is silicon oxide or a composite material of silicon oxide and a buffer material, and the shell is one or more coating layers or particle layers formed by carbon, carbon particles, carbon fibers or carbon nanotubes with a protection effect;
the silicon oxide accounts for 5 to 95 percent of the mass ratio of the negative electrode material;
the buffer material is 1-300% of the mass of the silicon oxide;
the mass ratio of the shell to the cathode material is 0.1-10%;
in the Raman spectrum of the cathode material, the concentration is 475 +/-10 cm-1With amorphous bulges, and/or at 510±10cm-1Has a crystalline state peak; and is 1360 +/-20 cm-1And 1580 +/-20 cm-1With a characteristic peak for carbon.
The general formula of the silicon oxide alkene is SiAxOyX is greater than or equal to 0 and less than 10, and y is greater than 0 and less than 10; the general formula of the silylene is SiAxX is 0 or more and less than 10;
wherein A is one or more of Be, B, P, N, Na, Mg, Al, Ti, Li, Mg, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Ga, Ge, Mo, Sn, Ag, Bi, Pb, Sb or Ba.
The silicon oxide has a sheet structure, the thickness of the silicon oxide is 1-500nm, and the size of the silicon oxide is 10nm-10 mu m; and at least one metal silicon phase is contained therein.
The cushioning material includes: one or a combination of more of carbon, carbon black, carbon nanotubes, natural graphite, artificial graphite, expanded graphite, microporous graphite, graphite flakes, nano metal particles or metal fibers, and is used for buffering the expansion and contraction of the material caused by the volume change of the silicon oxide or the silicon alkene material in the charging and discharging processes. The particle size of the buffer material is 10nm-20 microns, and the volume change of the buffer material in the lithium extraction process is not more than 50%.
The cathode material still keeps a core-shell structure after the lithium battery is cycled, wherein the inner core is a composite material of lithium-deintercalated silicon oxide or silylene and a buffer material after the lithium battery is cycled, and the lithium-deintercalated silicon oxide or silylene is formed by compounding one or more of metal silicon, lithium silicon alloy, doped metal silicon, doped lithium silicon alloy, lithium silicate, lithium oxide, a compound silicic acid compound and a compound oxide; the shell is a composite material of a carbon coating layer and a solid electrolyte interface SEI film generated by a lithium battery cycling side reaction.
The specific mass capacity of the negative electrode material used as the negative electrode material of the lithium ion battery is 400-2500 mAh/g.
The cathode material for the lithium battery with the core-shell structure can be used as a cathode material of a lithium ion battery, a lithium ion capacitor, a lithium sulfur battery, an all-solid-state lithium battery and the like or a part of the cathode material.
In order to better understand the preparation process of the negative electrode material and the performance characteristics thereof, the following description is provided with reference to some specific examples.
Example 1
The present example provides a method of preparing a silicon carbon composite having a core-shell structure, comprising:
the first step is as follows: a sucrose solution was prepared by adding 30g of sucrose to 100mL of a mixed solvent of ethanol and water (volume ratio: 1: 2). 10g of a silylene oxide sample and 1g of carbon black (average particle size of 50nm) were added to the sucrose solution and stirred to form a uniform slurry.
The second step is that: the slurry was dried at 120 ℃ for 8 hours to completely remove the solvent. The obtained product is put in a tube furnace at 600 ℃ and high-purity N2The mixture is pyrolyzed for 8 hours, cooled, ground and sieved (400 meshes).
The third step: and (3) putting the sieved sample into a tubular furnace filled with argon, heating to 900 ℃, switching argon into a mixed gas of argon and acetylene gas (the volume ratio is 4:1), and heating for 10 hours at 900 ℃ to obtain the composite material with the core-shell structure.
The Raman spectrum of the composite material is 475 +/-10 cm as shown in figure 1-1Has an amorphous bulge of 510 +/-10 cm-1Has a crystalline state peak; and is 1360 +/-20 cm-1And 1580 +/-20 cm-1With a characteristic peak for carbon.
SEM experiments of the present invention were conducted on a scanning electron microscope model S-4800, and the following examples are the same.
An SEM image of the silicon carbon composite material having the core-shell structure obtained in this example is shown in fig. 2.
The composite material of the carbon nanotube-containing silicon oxide composite material and commercial graphite in proportion is compounded into a composite material of 450mAh/g, and the composite material and lithium cobaltate are assembled into a button type full cell, and the button type full cell is cycled at 1C/1C to evaluate the cycle performance. The capacity fade graph is shown in fig. 3, and the data is recorded in table 1 for comparison.
Example 2
The present example provides a method of preparing a silicon carbon composite having a core-shell structure, comprising:
the first step is as follows: 10g of a sample of the silylene oxide was mixed with 5g of pitch and ball milled for 8 hours.
The second step is that: the ball-milled product is placed in a tube furnace at 500 ℃ and high-purity N2The mixture is pyrolyzed for 2 hours, cooled, ground and sieved (400 meshes).
The third step: and (3) putting the sieved sample into a tubular furnace filled with argon, heating to 900 ℃, switching argon into a mixed gas of argon and acetylene gas (the volume ratio is 3:1), and heating at 900 ℃ for 8 hours to obtain the composite material with the core-shell structure. The data are recorded in table 1.
Example 3
The present example provides a method of preparing a silicon carbon composite having a core-shell structure, comprising:
the first step is as follows: 10g of a sample of silylene oxide and 5g of glucose were mixed and ball milled for 2 hours.
The second step is that: the mixture after ball milling is put into a tube furnace at 600 ℃, and the high-purity N is obtained2The mixture is pyrolyzed for 5 hours, cooled, ground and sieved (400 meshes).
The third step: and (3) putting the sieved sample into a tubular furnace filled with argon, heating to 900 ℃, switching argon into a mixed gas of argon and acetylene gas (the volume ratio is 4:1), and heating at 900 ℃ for 8 hours to obtain the composite material with the core-shell structure. The data are recorded in table 1.
Example 4
The present example provides a method of preparing a silicon carbon composite having a core-shell structure, comprising:
the first step is as follows: 10g of a sample of silylene oxide and 5g of glucose were mixed and ball milled for 2 hours.
The second step is that: the obtained product is put in a tube furnace at 600 ℃ and high-purity N2The mixture is pyrolyzed for 5 hours, cooled, ground and sieved (400 meshes).
The third step: dissolving 5g PVP (polyvinylpyrrolidone) and the sieving material in 20mL ethanol, volatilizing the ethanol completely, placing the material in a tube furnace at 600 deg.C, and adding high-purity N2Pyrolyzing for 3 hours to obtain the composite with the core-shell structureAnd (5) synthesizing the materials. The data are recorded in table 1.
Example 5
The present example provides a method of preparing a silicon carbon composite having a core-shell structure, comprising:
the first step is as follows: a sucrose solution was prepared by adding 30g of sucrose to 100mL of a mixed solvent of ethanol and water (volume ratio: 1: 2). 10g of a silylene oxide sample and 1g of carbon black (average particle size of 20nm) were added to the sucrose solution and stirred to form a uniform slurry.
The second step is that: the slurry was dried at 120 ℃ for 6 hours to completely remove the solvent. The obtained product is put in a tube furnace at 600 ℃ and high-purity N2The mixture is pyrolyzed for 6 hours, cooled, ground and sieved (400 meshes).
The third step: dissolving 5g PVP (polyvinylpyrrolidone) and the sieving material in 20mL ethanol, volatilizing the ethanol completely, placing the material in a tube furnace at 600 deg.C, and adding high-purity N2And pyrolyzing for 3 hours to obtain the composite material with the core-shell structure. The data are recorded in table 1.
Example 6
The present example provides a method of preparing a silicon carbon composite having a core-shell structure, comprising:
the first step is as follows: 100mL of acetone was taken and 10g of phenol resin was added to form a phenol resin solution. 10g of a silicon oxide alkene sample and 1g of acetylene black (with the average particle size of 30nm) are added into a phenolic resin starch solution and stirred for 2 hours to form uniform slurry.
The second step is that: the slurry was dried at 120 ℃ for 5 hours to completely remove the solvent. The obtained product is put in a tube furnace at 600 ℃ and high-purity N2The mixture is pyrolyzed for 5 hours, cooled, ground and sieved (400 meshes).
The third step: and (3) putting the sieved sample into a tubular furnace filled with argon, heating to 900 ℃, switching argon into a mixed gas of argon and acetylene (the volume ratio is 3:1), and heating at 900 ℃ for 1 hour to obtain the composite material with the core-shell structure. The data are recorded in table 1.
Example 7
The present example provides a method of preparing a silicon carbon composite having a core-shell structure, comprising:
the first step is as follows: 100mL of acetone was taken and 10g of phenol resin was added to form a phenol resin solution. 10g of a sample of the silylene oxide and 1g of carbon black (average particle size of 30nm) were added to the phenolic resin solution and stirred for 2 hours to form a homogeneous slurry.
The second step is that: the slurry was dried at 120 ℃ for 8 hours to completely remove the solvent. The obtained product is put in a tube furnace at 600 ℃ and high-purity N2The mixture is pyrolyzed for 5 hours, cooled, ground and sieved (400 meshes).
The third step: dissolving 5g PVP (polyvinylpyrrolidone) and the sieving material in 20mL ethanol, volatilizing the ethanol completely, placing the material in a tube furnace at 600 deg.C, and adding high-purity N2And pyrolyzing for 3 hours to obtain the composite material with the core-shell structure. The data are recorded in table 1.
Example 8
The present example provides a method of preparing a silicon carbon composite having a core-shell structure, comprising:
the first step is as follows: 1g of pitch was dissolved in 100mL of quinoline to form a quinoline solution. 1g of a sample of a silylene oxide and 10g of carbon black (average particle size of 20nm) were added to the phenolic resin solution and stirred for 1 hour to form a uniform slurry.
The second step is that: the slurry was dried at 120 ℃ for 8 hours to completely remove the solvent. The obtained product is put in a tube furnace at 600 ℃ and high-purity N2The mixture is pyrolyzed for 5 hours, cooled, ground and sieved (400 meshes).
The third step: dissolving 5g PVP (polyvinylpyrrolidone) and the sieving material in 20mL ethanol, volatilizing the ethanol completely, placing the material in a tube furnace at 600 deg.C, and adding high-purity N2And pyrolyzing for 3 hours to obtain the composite material with the core-shell structure. The data are recorded in table 1.
Example 9
The present example provides a method of preparing a silicon carbon composite having a core-shell structure, comprising:
the first step is as follows: 1g of pitch was dissolved in 100mL of quinoline to form a quinoline solution. 1g of a silicon oxide alkene sample and 1g of mesocarbon microbeads (average particle size of 2 microns) are added into a phenolic resin solution and stirred for 1h to form uniform slurry.
The second step is that: the slurry was dried at 120 ℃ for 8 hours to completely remove the solvent. The obtained product is put in a tube furnace at 600 ℃ and high-purity N2The mixture is pyrolyzed for 5 hours, cooled, ground and sieved (400 meshes).
The third step: and (3) putting the sieved sample into a tubular furnace filled with argon, heating to 900 ℃, switching argon into a mixed gas of argon and toluene (the volume ratio is 3:1), and heating for 2 hours at 900 ℃ to obtain the composite material with the core-shell structure. The data are recorded in table 1.
Example 10
The present example provides a method of preparing a silicon carbon composite having a core-shell structure, comprising:
the first step is as follows: 1g of pitch was dissolved in 100mL of quinoline to form a quinoline solution. 1g of a silicon oxide alkene sample and 1g of mesocarbon microbeads (average particle size of 2 microns) are added into a phenolic resin solution and stirred for 1 hour to form uniform slurry.
The second step is that: the slurry was dried at 120 ℃ for 8 hours to completely remove the solvent. The obtained product is put in a tube furnace at 600 ℃ and high-purity N2The mixture is pyrolyzed for 5 hours, cooled, ground and sieved (400 meshes).
The third step: dissolving 5g of phenolic resin and the sieving material in 20mL of acetone, uniformly mixing, volatilizing the acetone completely in an oven, placing the material in a tubular furnace at 600 ℃, and preparing high-purity N2And pyrolyzing for 3 hours to obtain the composite material with the core-shell structure. The data are recorded in table 1.
Comparative example 1
The present example provides a method of preparing a silicon carbon composite having a core-shell structure, comprising:
the first step is as follows: a sucrose solution was prepared by adding 30g of sucrose to 100mL of a mixed solvent of ethanol and water (volume ratio: 1: 2). 10g of nano silicon powder sample and 1g of carbon black (with the average particle size of 50nm) are added into the sucrose solution and stirred to form uniform slurry. 30g of spheroidal graphite (average particle size: 10 μm) was added to the slurry, followed by stirring.
The second step is that: the slurry was dried at 120 ℃ for 8 hours to completely remove the solvent. The obtained product is put in a tube furnace at 600 ℃ and high-purity N2The mixture is pyrolyzed for 8 hours, cooled, ground and sieved (400 meshes).
The third step: and (3) putting the sieved sample into a tubular furnace filled with argon, heating to 900 ℃, switching argon into a mixed gas of argon and acetylene gas (the volume ratio is 4:1), and heating for 10 hours at 900 ℃ to obtain the composite material with the core-shell structure. The data are recorded in table 1.
The electrochemical performance of the negative electrode materials for lithium batteries prepared in examples 1 to 10 is compared with that of comparative example 1 as shown in table 1 below.
Figure BDA0002234170130000111
TABLE 1
The negative electrode material for the lithium battery provided by the embodiment of the invention has a core-shell structure, the problem caused by volume change in the charging and discharging processes of the battery is relieved through the shell coating layer or the particle layer, and the problem of low first-cycle coulombic efficiency caused by high specific surface area is improved, so that the silicon-carbon composite material has the advantages of long cycle and high stability, and the silicon oxide alkene material simultaneously ensures higher capacity and first-cycle coulombic efficiency.
The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims (9)

1. The negative electrode material for the lithium battery with the core-shell structure is characterized in that the negative electrode material is a silicon-carbon composite material with the core-shell structure;
the inner core of the negative electrode material is a composite material of silicon oxide or silicon alkene and a buffer material, and the shell is one or more coating layers or particle layers formed by carbon, carbon particles, carbon fibers or carbon nanotubes with a protection effect;
the silicon oxide accounts for 5-95% of the mass ratio of the negative electrode material;
the buffer material accounts for 1% -300% of the mass of the silicon oxide;
the mass ratio of the shell to the anode material is 0.1-10%;
in the Raman spectrum of the cathode material, the concentration is 475 +/-10 cm-1Has an amorphous bulge, and/or is within 510 + -10 cm-1Has a crystalline state peak; and is 1360 +/-20 cm-1And 1580 +/-20 cm-1A characteristic peak with carbon;
the negative electrode material still keeps a core-shell structure after the lithium battery is cycled, wherein the kernel is a composite material of lithium-deintercalated silicon oxide or silylene and a buffer material after the lithium battery is cycled, and the lithium-deintercalated silicon oxide or silylene is formed by compounding one or more of metal silicon, lithium silicon alloy, doped metal silicon, doped lithium silicon alloy, lithium silicate, lithium oxide, a compound silicic acid compound and a compound oxide; the shell is a composite material of a carbon coating layer and a solid electrolyte interface SEI film generated by a lithium battery cycling side reaction.
2. The negative electrode material according to claim 1,
the general formula of the silicon oxide alkene is SiAxOyX is greater than or equal to 0 and less than 10, and y is greater than 0 and less than 10;
the general formula of the silylene is SiAxX is 0 or more and less than 10;
wherein A is one or more of Be, B, P, N, Na, Mg, Al, Ti, Li, Mg, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Ga, Ge, Mo, Sn, Ag, Bi, Pb, Sb or Ba elements.
3. The negative electrode material of claim 1, wherein the silylene oxide has a sheet structure with a thickness of 1-500nm and a size of 10nm-10 μm; and at least one metal silicon phase is contained therein.
4. The anode material according to claim 1, wherein the buffer material comprises: one or a combination of more of carbon, carbon black, carbon nanotubes, natural graphite, artificial graphite, expanded graphite, microporous graphite, graphite flakes, nano metal particles or metal fibers, and is used for buffering the expansion and contraction of the material caused by the volume change of the silicon oxide or the silicon alkene material in the charging and discharging processes.
5. The anode material according to claim 4, wherein the buffer material has a particle size of 10nm to 20 μm, and a volume change of the buffer material during lithium deintercalation is not more than 50%.
6. The negative electrode material as claimed in claim 1, wherein the negative electrode material has a specific mass capacity of 400-2500mAh/g as a negative electrode material of a lithium ion battery.
7. A negative electrode plate, characterized in that the negative electrode plate comprises the negative electrode material of any one of claims 1 to 6.
8. The negative electrode tab of claim 7, wherein the negative electrode tab is used in a lithium ion battery, a lithium ion capacitor, a lithium sulfur battery, or an all solid state lithium battery.
9. A lithium battery comprising the negative electrode material as claimed in any one of claims 1 to 6.
CN201910977656.1A 2019-10-15 2019-10-15 Lithium battery negative electrode material with core-shell structure and lithium battery Withdrawn CN110690452A (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114149008A (en) * 2021-12-03 2022-03-08 北京蒙京石墨新材料科技研究院有限公司 Composite silylene material, preparation method thereof and lithium ion battery
CN114171717A (en) * 2021-12-15 2022-03-11 滨州学院 Silicon-olefin composite material for lithium ion battery and preparation method thereof
US20220149358A1 (en) * 2020-11-12 2022-05-12 Sk Innovation Co., Ltd. Negative Electrode Active Material Including Core-Shell Composite and Method of Preparing the Same
CN118173766A (en) * 2024-05-14 2024-06-11 溧阳紫宸新材料科技有限公司 Composite carbon material and preparation method and application thereof

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20220149358A1 (en) * 2020-11-12 2022-05-12 Sk Innovation Co., Ltd. Negative Electrode Active Material Including Core-Shell Composite and Method of Preparing the Same
CN114149008A (en) * 2021-12-03 2022-03-08 北京蒙京石墨新材料科技研究院有限公司 Composite silylene material, preparation method thereof and lithium ion battery
CN114171717A (en) * 2021-12-15 2022-03-11 滨州学院 Silicon-olefin composite material for lithium ion battery and preparation method thereof
CN118173766A (en) * 2024-05-14 2024-06-11 溧阳紫宸新材料科技有限公司 Composite carbon material and preparation method and application thereof

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