Lithium ion battery, lithium ion battery negative electrode material and preparation method thereof

A technology for lithium-ion batteries and negative electrode materials, applied in battery electrodes, secondary batteries, nanotechnology for materials and surface science, etc., can solve problems such as not fully meeting service life requirements, cycle life decay, electrode cracking, etc. Achieve the effects of improving the first Coulomb efficiency, inhibiting volume expansion, and reducing the contact area

Active Publication Date: 2019-11-05
DONGGUAN DONGYANG SOLAR SCI RES & DEV CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The theoretical specific capacity of pure silicon negative electrode is 4200mAh / g, which is more than 10 times that of graphite negative electrode (372mAh / g). The lattice expansion, the volume expansion rate is greater than 300% (graphite is only 12%), resulting in pulverization of the active material, and even loss of electrical contact with the current collector, repeated damage and repair of the SEI film, irreversible consumption of limited lithium ions, cycle life severe attenuation
[0004] Carbon coating is currently the mainstream solution to solve the volume expansion of silicon-based negative electrode materials and improve the conductivity. Although the material rate and cycle performance have been improved to a certain extent, the strength and toughness of carbon materials cannot withstand silicon during charge and discharge. Repeated volume expansion and contraction, after many cycles, there will still be damage to the material structure, electrode cracking, and even powder dropping, so the cycle performance still cannot fully meet the service life requirements

Method used

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  • Lithium ion battery, lithium ion battery negative electrode material and preparation method thereof
  • Lithium ion battery, lithium ion battery negative electrode material and preparation method thereof
  • Lithium ion battery, lithium ion battery negative electrode material and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0041] 1. Spray granulation:

[0042] Silicon source: nano silicon powder, particle size 150nm, purity > 99.9%; graphite source: artificial graphite, particle size 12 μm, purity > 99.9%; dispersant: polyethylene glycol 1500, analytically pure; organic carbon source: sucrose, analytically pure ;

[0043] Fully disperse 5 parts of silicon source, 5 parts of graphite source, 1 part of polyethylene glycol 1500, and 2 parts of sucrose in deionized water to obtain a spray slurry with 25% solid content; when the inlet temperature is 185 °C and the outlet temperature is 103 The above-mentioned slurry was subjected to spray granulation on a two-fluid spray dryer at ℃ to obtain the first precursor.

[0044] 2. Pyrolysis of the first precursor:

[0045] The above-mentioned first precursor was subjected to high-temperature pyrolysis at 800° C. for 5 h in a nitrogen atmosphere to obtain a second precursor coated with amorphous carbon. The amount of carbon coating was about 5% based on th...

Embodiment 2

[0049] 1. Spray granulation:

[0050] Silicon source: silicon oxide (x is 1), particle size 5 μm, purity > 99.9%; graphite source: flake graphite, particle size 10 μm, purity > 99.9%; dispersant: polyethylene glycol 2000, analytically pure; organic carbon source : Glucose, analytically pure;

[0051] Fully disperse 5 parts of silicon source, 2 parts of graphite source, 1 part of polyethylene glycol 2000, and 3 parts of glucose in deionized water to obtain a spray slurry with a solid content of 15%; when the inlet temperature is 175 °C and the outlet temperature is 92 In a centrifugal spray dryer at ℃, spray granulate the above slurry to obtain the first precursor.

[0052] 2. Pyrolysis of the first precursor:

[0053] The above-mentioned first precursor was subjected to high-temperature pyrolysis at 900° C. for 6 hours under an argon atmosphere to obtain a second precursor coated with amorphous carbon. The amount of carbon coating was about 2% based on the residual carbon af...

Embodiment 3

[0057] 1. Spray granulation:

[0058] Silicon source: nano silicon powder, particle size 100nm, purity>99.9%; graphite source: artificial graphite, particle size 8μm, purity>99.9%; dispersant: polyvinylpyrrolidone k13-18, analytically pure; organic carbon source: phenolic resin, Analytical pure;

[0059] Fully disperse 1 part of silicon source, 5 parts of graphite source, 2 parts of polyvinylpyrrolidone k13-18, and 1.5 parts of phenolic resin in absolute ethanol to obtain a spray slurry with a solid content of 20%; On a closed-loop three-fluid spray dryer at a temperature of 80° C., the above slurry was subjected to spray granulation to obtain a first precursor.

[0060] 2. Pyrolysis of the first precursor:

[0061] The above-mentioned first precursor was subjected to high-temperature pyrolysis at 900° C. for 10 h in an argon atmosphere to obtain a second precursor coated with amorphous carbon. The amount of carbon coating was 11.75% based on the residual carbon after pyroly...

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Abstract

The invention discloses a lithium ion battery, a lithium ion battery negative electrode material and a preparation method thereof. The lithium ion battery negative electrode material comprises a composite microsphere of silicon/silicon oxide compound and graphite, an amorphous carbon layer coated on the surface of the composite microsphere and a copper layer coated outside a part of the amorphouscarbon layer. A copper-carbon double-layer coating structure is successfully constructed by coating the amorphous carbon layer on the composite microsphere of silicon/silicon oxide compound and graphite and then plating the copper layer outside the amorphous carbon layer. The copper can be used as a good conductor and can improve the electron conductance of the lithium ion battery, and the coppercan also be used as a ductile metal to provide a high-strength coating layer, effectively suppress the volume expansion of silicon, avoid the powdering of active materials such as silicon/silicon oxide compound, reduce the specific surface area of the composite microsphere by double-layer coating, reduce the contact area between the active materials such as silicon/silicon oxide compound and electrolyte and improve the first coulomb efficiency, rate performance and cycle performance of the lithium ion battery negative electrode material.

Description

technical field [0001] The embodiments of the present invention relate to the technical field of lithium-ion battery anode materials, and in particular to a lithium-ion battery, a lithium-ion battery anode material and a preparation method thereof. Background technique [0002] The anode materials of commercial lithium-ion batteries are mainly artificial graphite and modified natural graphite. Graphite has low cost, good cycle stability, and excellent rate. However, with the rapid development of electric vehicles, the energy density of lithium-ion batteries is far from meeting the current market There is an urgent need to develop positive and negative electrode materials with high energy density. At present, high-energy-density cathode materials are represented by high-nickel ternary materials, while silicon-based anode materials are the development trend. [0003] The theoretical specific capacity of pure silicon negative electrode is 4200mAh / g, which is more than 10 times...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/38H01M4/485H01M4/62H01M10/0525B82Y30/00
CPCH01M4/366H01M4/386H01M4/485H01M4/625H01M4/626H01M10/0525B82Y30/00Y02E60/10
Inventor 谌庆春彭果戈周政杨超夏振宇母龙均李向东胡三元
Owner DONGGUAN DONGYANG SOLAR SCI RES & DEV CO LTD
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