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A kind of composite negative plate of lithium ion secondary battery and its preparation method and lithium ion secondary battery

A technology of secondary battery and negative electrode sheet, which is applied in the direction of secondary battery, battery electrode, non-aqueous electrolyte battery electrode, etc. The effect of capacity

Active Publication Date: 2017-08-25
HUAWEI TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] In view of this, the first aspect of the embodiment of the present invention provides a lithium-ion secondary battery composite negative electrode sheet, which is used to solve the problem that the silicon material is easily detached from the current collector due to the volume expansion effect in the prior art, and the simple silicon material The problem of making the overall conductivity of the negative electrode sheet lower, thereby improving the capacity and cycle life of lithium-ion secondary batteries

Method used

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  • A kind of composite negative plate of lithium ion secondary battery and its preparation method and lithium ion secondary battery

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preparation example Construction

[0038] In a second aspect, an embodiment of the present invention provides a method for preparing a composite negative electrode sheet of a lithium-ion secondary battery, comprising the following steps:

[0039] A silicon-based active material layer with a thickness of 5 nm to 2 μm is deposited on the metal current collector by chemical vapor deposition or magnetron sputtering as the first negative electrode active layer; the material of the silicon-based active material layer is silicon One or more of nanoparticles, nanowires and nanorods based on active materials;

[0040] Disperse the material of the second negative electrode active layer, the negative electrode active material, the binder and the conductive agent in the solvent at a mass ratio of 80 to 99:1 to 20:1 to 20, and stir to form a uniform slurry. The negative electrode active material is carbon At least one of the plain negative electrode material and lithium titanate, the obtained slurry is evenly coated on the ...

Embodiment 1

[0067] A preparation method of a lithium-ion secondary battery composite negative plate, comprising the following steps:

[0068](1) Provide a clean nickel foil current collector with a thickness of 10 μm, and deposit a silicon layer on the current collector by chemical vapor deposition. Specifically, place the nickel foil current collector in a quartz tube, pump the tube furnace Vacuum, feed silane and argon at a ratio of 1:10 by volume, control the gas flow to 30 sccm, raise the temperature in the tube furnace to 700°C at a heating rate of 10°C / min and keep it warm for 30min, then cool to room temperature to obtain Nickel foil current collector with a silicon layer deposited on the surface;

[0069] (2) Mix natural graphite with conductive agents (Timcal, Super-P and SFG-6) evenly, then add 8% polyvinylidene fluoride PVDF (Arkmer, HSV900) in N-methylpyrrolidone solution, and then in a vacuum mixer stirring in medium to form a uniform slurry, which is evenly coated on the su...

Embodiment 2

[0072] A preparation method of a lithium-ion secondary battery composite negative plate, comprising the following steps:

[0073] (1) Provide a clean copper foil current collector with a thickness of 20 μm, and deposit a silicon layer on the current collector by magnetron sputtering. Specifically, place the copper foil current collector in the magnetron sputtering chamber to Silicon is used as the target material, and the vacuum is evacuated to 1×10 -2 Pa, argon gas with a gas flow rate of 100 sccm is introduced to the pressure of the magnetron sputtering chamber to 3Pa, the control power is 80W, sputtering at 200°C for 2min, and then cooled to room temperature to obtain a copper foil current collector with a silicon layer deposited on the surface ;

[0074] (2) Mix the artificial graphite with the conductive agent (Timcal, Super-P and KS-6) evenly, then add 8% polyvinylidene fluoride PVDF (Arkmer, HSV900) in N-methylpyrrolidone solution, and then in a vacuum mixer Stir in m...

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Abstract

The invention provides a composite negative electrode sheet of lithium ion secondary battery. The composite negative electrode sheet comprises a metal current collector and a silicon based active material layer which is deposited on the surface of the current collector, and further comprises a second negative electrode active layer which is painted on the surface of the silicon based active material layer. The thickness of the silicon based active material layer is 5 nm to 2 [mu]m. The silicon based active material layer is composed of one or more components of nano particles and nano lines of a silicon based active material. The second negative electrode active layer is made of a negative electrode active material, a binder, and a conductive agent. In the lithium ion secondary battery composite negative electrode sheet, the silicon based active material layer is firmly adhered on the surface of the current collector and is capable of increasing the capacity of the negative electrode sheet; and the second negative electrode active layer can reduce the contact between the silicon material and the electrolyte, buffer the volume expansion effect of the silicon material, and guarantee the battery cycle life. The invention also provided a preparation method of the lithium ion secondary battery composite negative electrode sheet, and a lithium ion secondary battery containing the lithium ion secondary battery composite negative electrode sheet.

Description

technical field [0001] The invention relates to the field of lithium-ion secondary batteries, in particular to a lithium-ion secondary battery composite negative electrode sheet, a preparation method thereof, and a lithium-ion secondary battery. Background technique [0002] With the increasingly higher energy density requirements of portable electronic devices and electric vehicles, the research and development of high-performance lithium-ion secondary batteries is becoming increasingly important. [0003] With the continuous exploration of negative electrode materials, materials that can form alloys with lithium (Si, Sn, Ge, Mg, Sb, Al, Zn, etc.) have become high-energy materials due to their high theoretical capacity and good insertion / extraction capabilities. The most promising class of anode materials in lithium-ion secondary batteries. For example, the theoretical capacity of pure silicon material is as high as 4200mAh / g, about ten times that of graphite negative elec...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01M4/13H01M4/139
CPCH01M4/131H01M4/133H01M4/134H01M4/1393H01M4/1395H01M10/0525Y02E60/10
Inventor 夏圣安王平华杨俊
Owner HUAWEI TECH CO LTD
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