Modified composite material containing silicon-based material, preparation method thereof and use thereof in lithium ion battery

A technology of composite materials and silicon-based materials, applied in battery electrodes, secondary batteries, active material electrodes, etc., can solve the problems of carbon tubes lack of ductility, unable to prevent and delay particle pulverization, and unable to effectively absorb, etc., to achieve improved Overall performance, improved cycle performance, and reduced electrode crushing effects

Inactive Publication Date: 2018-12-28

JIANGSU TAFEL NEW ENERGY TECH CO LTD +2

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AI-Extracted Technical Summary

Problems solved by technology

For example, CN 104112847A discloses a silicon-based negative electrode material and its method. The silicon-based negative electrode material includes: carbon tubes and nano-silicon particles located inside the carbon tubes. Since the carbon tubes have voids inside, the silicon particles can be fixed on the In the limited space in the carbon tube, the volume expansion or contraction of the silicon particles is within the limited space, which not on...

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Method used

Adopt the SiO of this comparative example and artificial graphite to mix according to the ratio of 1:9, adopt the method identical with embodiment 1 to make negative pole and further assemble into lithium-ion battery, measure its energy density and cycle performance. Its energy density is 230Wh/kg, and the cycle capacity decay curve is shown in Figure 1 (cycle test conditions are the same as in Example 1). It can be seen from Fig. 1 that the lithium-ion pouch battery made of the modified composite material containing the silicon-based material of the present invention can greatly improve the cycle performance of the battery.

Adopt the modified composite material of the present embodiment and artificial graphite to mix according to the ratio of 1:9 as negative active material, adopt the method identical with embodiment 1 to make negative pole and be further assembled into lithium-ion battery, reach and improve lithium ion The effect of high energy density and long cycle performance. Its energy density is 230Wh/kg, and the cycle capacity decay curve is shown in Figure 1 (cycle test conditions are the same as in Example 1).

Adopt the modified composite material of the present embodiment and artificial graphite to mix according to the ratio of 1:9 as negative active material, make negative pole and be ...

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Abstract

The invention discloses a modified composite material containing a silicon base material, which comprises a silicon base core and a polymer cladding layer covering the surface of the core, and a preparation method and use thereof in a lithium ion battery. The method comprises the steps of : 1) adding a polymer into a liquid solvent and dispersing to obtain a slurry; 2) adding a silicon-based material or a mixture of that silicon-based material and the carbon material into the slurry and mixing the solid and liquid; 3) removing the solvent to obtain a modified composite material containing a silicon-based material. As the polymer coat layer is introduced on the surface of the silicon base core, so that the electrolyte can be isolated and the side reaction of the electrolyte on the surface of the silicon base core can be prevented; the method can also improve the crushing, electrode pulverization and peeling of the silicon-based negative electrode material in the process of processing and using, and reduce the electrode crushing and peeling caused by the huge volume expansion of the silicon-based material in the process of charging and discharging, so as to achieve the purpose of stabilizing the electrode structure and improving the cell cycle performance.

Application Domain

Negative electrodesSecondary cells

Technology Topic

SolventCharge and discharge +10

Image

Examples

Experimental program(5)
Comparison scheme(1)

Example Embodiment

[0050] Example 1

[0051] This embodiment provides a modified composite material containing a silicon-based material, the composite material is: a SiO core and a polymer coating layer covering the surface of the core, the composition of the polymer coating layer is Polyvinylidene fluoride;

[0052] The particle size D50 of the SiO core is 5 μm, and the thickness of the polyvinylidene fluoride coating layer is 10 nm;

[0053] Based on the total mass of the modified composite material being 100 wt%, the polyvinylidene fluoride coating layer has a mass percentage of 3 wt%.

[0054] Preparation:

[0055] (1) Disperse the polymer in the NMP liquid solvent, uniformly disperse it by stirring, vibration, ultrasound and other methods to obtain a slurry;

[0056] (2) Add the SiO negative electrode material to the slurry, and achieve uniform solid-liquid mixing by stirring, vibration, ultrasonic and other methods;

[0057] (3) Use filtration, evaporation and other methods to remove the solvent, so that the high molecular polymer is dispersed on the surface of the SiO-containing negative electrode material to form a coating layer;

[0058] (4) Heat treatment is used to increase the degree of crosslinking of the coating layer so as not to dissolve and disperse again during subsequent processing and use. The heat treatment temperature is 150° C. and the time is 24 hours to finally obtain the modified composite material.

[0059] application:

[0060] The modified composite material of this embodiment and the artificial graphite are mixed in a ratio of 1:9 as the negative electrode active material to form the negative electrode and further assembled into a lithium ion battery to achieve the effect of improving the high energy density and long cycle performance of lithium ion. Its energy density is 230Wh/kg, and the cyclic capacity attenuation curve is shown in figure 1 (The cycle test conditions are: 0.5C charge and 1C discharge at 25°C).

[0061] The specific steps for preparing a lithium ion battery in this embodiment are: dispersing the positive electrode material, conductive agent, and positive electrode binder in NMP and stirring to form a positive electrode slurry, coating on aluminum foil, drying, rolling, and cutting to obtain a positive electrode. Sheet: Disperse the negative electrode material, the conductive agent, and the negative electrode binder in water and stir to form a negative electrode slurry, which is coated on the copper foil and dried, rolled, and cut to obtain a negative electrode sheet. The above-mentioned positive and negative pole pieces are wound together with the separator, the aluminum plastic film is wrapped, and the electrolyte is injected and sealed. The soft-packed lithium-ion battery for testing is finally obtained after the process of standing, forming, and dividing.

Example Embodiment

[0062] Example 2

[0063] This embodiment provides a modified composite material containing a silicon-based material, and the composite material is: SiO 1.5 A core, and a polymer coating layer covering the surface of the core, the composition of the polymer coating layer is: a combination of CMC, SBR and polyaniline in a mass ratio of 1:4:5;

[0064] The particle size D50 of the SiO core is 5 μm-10 μm, and the thickness of the polymer coating layer is 10 nm-25 nm;

[0065] Based on the total mass of the modified composite material being 100 wt%, the mass percentage of the polymer coating layer is 3 wt%.

[0066] Preparation:

[0067] (1) Disperse CMC, SBR and polyaniline in water, uniformly disperse them by stirring, vibration, ultrasound and other methods to obtain slurry;

[0068] (2) SiO 1.5 The negative electrode material is added to the slurry, and the solid and liquid are uniformly mixed by stirring, vibration, ultrasound and other methods;

[0069] (3) Use filtration, evaporation and other methods to remove the solvent to disperse the polymer in the SiO 1.5 A coating layer is formed on the surface of the negative electrode material;

[0070] (4) Heat treatment is used to increase the degree of crosslinking of the coating layer so that it will not be dissolved and dispersed again during subsequent processing and use. The heat treatment temperature is 200° C. and the time is 3 hours to finally obtain the modified composite material.

[0071] application:

[0072] The modified composite material of this embodiment is mixed with artificial graphite in a ratio of 1:9 as the negative electrode active material, and the negative electrode is made by the same method as in Example 1 and further assembled into a lithium ion battery to achieve high lithium ion energy density And the effect of long cycle performance. Its energy density is 230Wh/kg, and the cyclic capacity attenuation curve is shown in figure 1 (Circulation test conditions are the same as in Example 1).

Example Embodiment

[0073] Example 3

[0074] This embodiment provides a modified composite material containing a silicon-based material, the composite material is: a SiO core and a polymer coating layer covering the surface of the core, the composition of the polymer coating layer is : CMC, SBR, sodium alginate and PAA in a combination of 1:4:1:1;

[0075] The particle size D50 of the SiO core is 10 μm to 15 μm, and the thickness of the polymer coating layer is 30 nm to 50 nm;

[0076] Based on the total mass of the modified composite material being 100 wt%, the mass percentage of the polymer coating layer is 5 wt%.

[0077] Preparation:

[0078] (1) Disperse CMC, SBR, sodium alginate and PAA in water, uniformly disperse them by stirring, vibration, ultrasound and other methods to obtain slurry;

[0079] (2) Add the SiO negative electrode material to the slurry, and achieve uniform solid-liquid mixing by stirring, vibration, ultrasonic and other methods;

[0080] (3) Use filtration, evaporation and other methods to remove the solvent, so that the high molecular polymer is dispersed on the surface of the SiO-containing negative electrode material to form a coating layer;

[0081] (4) Heat treatment is used to increase the degree of crosslinking of the coating layer so as not to dissolve and disperse again during subsequent processing and use. The heat treatment temperature is 125° C. and the time is 12 hours to finally obtain the modified composite material.

[0082] application:

[0083] The modified composite material of this embodiment is mixed with artificial graphite in a ratio of 1:9 as the negative electrode active material, and the negative electrode is made by the same method as in Example 1 and further assembled into a lithium ion battery to achieve high lithium ion energy density And the effect of long cycle performance. Its energy density is 230Wh/kg, and the cyclic capacity attenuation curve is shown in figure 1 (Circulation test conditions are the same as in Example 1).

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PUM

Property	Measurement	Unit
Thickness	5.0 ~ 50.0	nm
Particle size	1.0 ~ 20.0	µm
Particle size	5.0	µm
tensile		MPa
Particle size		Pa
strength	10

Description & Claims & Application Information

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Classification and recommendation of technical efficacy words

Stable electrode structure
Improve overall performance

Lithium ion battery anode material based on metal oxide and preparation method thereof

ActiveCN111969191AHigh tap densityStable electrode structureCell electrodesSecondary cellsLithium hydrideLithium electrode

Owner:山东兴丰新能源科技有限公司

Modified composite material containing silicon-based material, preparation method thereof and use thereof in lithium ion battery

AI-Extracted Technical Summary

Problems solved by technology

Method used

Abstract

Image

Examples

Example Embodiment

Example Embodiment

Example Embodiment

PUM

Description & Claims & Application Information

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