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Silicon-based composite negative electrode plate, preparation method, and lithium ion secondary battery

A negative electrode, silicon-based technology, applied in secondary batteries, battery electrodes, circuits, etc., can solve the problems of limited cycle stability improvement, low electrical conductivity, and complicated preparation process, so as to broaden the commercial application prospects and improve the overall The effect of capacity, high cycle stability

Inactive Publication Date: 2018-03-13
HUAWEI TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the silicon negative electrode material will experience severe volume expansion (0-300%) during the lithium intercalation reaction process, which will lead to structural damage and pulverization of the electrode material, resulting in rapid capacity decay and shortened cycle life.
In addition, the silicon anode material itself has defects such as low conductivity, poor rate performance, and low initial charge and discharge efficiency.
In order to solve these problems, the industry mainly adopts nanometerization, thin filmization, compounding and other methods to improve the volume expansion effect of silicon, improve the cycle stability and rate performance of silicon, but the results are not ideal, or the cycle stability performance is limited. , or the introduction of a large amount of inactive substances greatly weakens the high-capacity advantage of pure silicon materials, or the preparation process is complicated and difficult to achieve commercialization

Method used

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  • Silicon-based composite negative electrode plate, preparation method, and lithium ion secondary battery
  • Silicon-based composite negative electrode plate, preparation method, and lithium ion secondary battery
  • Silicon-based composite negative electrode plate, preparation method, and lithium ion secondary battery

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preparation example Construction

[0044] Correspondingly, an embodiment of the present invention also provides a method for preparing a silicon-based composite negative electrode sheet, comprising the following steps:

[0045] Taking the current collector as the base, depositing and growing the nuclear negative electrode material in situ on the surface of the current collector by chemical deposition, the nuclear negative electrode material is arranged on the current collector in a one-dimensional vertical array structure; the nuclear negative electrode material is carbon One or more of nanotubes, carbon nanofibers, porous carbon, graphene, lithium-intercalated metals and alloys, lithium titanate, transition metal oxides, double metal oxides, metal sulfides, metal nitrides and metal phosphides kind;

[0046] Then, the silicon-based material is coated on the outer surface of the core negative electrode material by physical or chemical coating methods to obtain a one-dimensional silicon-based core-shell composite...

Embodiment 1

[0063] A method for preparing a silicon-based composite negative plate with a vertical tin (Sn) nanotube as a core, a Si / C composite as a shell, and a copper foil as a current collector, comprising the following steps:

[0064] (1) Copper foil is used as the deposition substrate, and the ZnO seed layer is deposited on the substrate by magnetron sputtering: First, put the copper foil in ethanol and acetone for 10 minutes, and then take it out and rinse it with deionized water several times, and dry it. Then put it into the vacuum chamber; evacuate to a vacuum degree of 2.4×10 -4 Pa, feed argon and oxygen, and heat the sample delivery chamber to 800°C; use a ZnO ceramic target with a purity of 99.9%, and magnetron sputtering for 0.5 hours to obtain a copper foil substrate with a ZnO seed layer deposited; LZn(NO 3 ) 2 In a mixed solution of 0.025mol / L hexamethylenetetramine, the ZnO seed layer grows into an array of ZnO nanorods arranged vertically through a hydrothermal reacti...

Embodiment 2

[0068] A vertical Zn 2 GeO 4 A method for preparing a silicon-based composite negative plate in which the nanowire is the core, the nano-Si particles are the shell, and the flexible carbon fiber cloth is the current collector, comprising the following steps:

[0069] (1) Using flexible carbon fiber cloth as a deposition substrate, it was sonicated in ethanol solution for 5 minutes and washed with deionized water to purify; 0.6g GeO 2 , 1.65g Zn(CH 3 COO) 2 ·H 2 O was added to a mixture of 60mL DETA and 20mL deionized water, and stirred continuously for 1 hour to obtain a homogeneous solution; the homogeneous solution was transferred together with the purified carbon fiber cloth to a 100mL hydrothermal reaction kettle, and subjected to hydrothermal reaction at 180°C After 48 hours, cool to room temperature; wash with deionized water and ethanol 5 times respectively, and dry to obtain vertical Zn 2 GeO 4 Carbon fiber cloth of nanowire array; wherein, the obtained Zn 2 GeO...

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Abstract

The invention provides a silicon-based composite negative electrode plate. The silicon-based composite negative electrode plate comprises a current collector, and a one-dimensional silicon-based shell-core composite structure array arranged on the current collector. According to the one-dimensional silicon-based shell-core composite structure array, a core negative electrode material formed on thecurrent collector via in-suit growth is taken as the core, and a silicon-based material is taken as a shell; the core negative electrode material is one or mixture of a plurality of ingredients selected from carbon nano tube, carbon nanofiber, porous carbon, graphene, lithium-intercalation metal and alloy, lithium titanate, a transition metal oxide, a bimetal oxide, a metal sulfide, a metal nitride, and a metal phosphide; and the core negative electrode material is arranged on the current collector in the manner of a one-dimensional vertical structure array. The silicon-based composite negative electrode plate possesses high-rate performance and high cycling stability, is capable of improving problems such as the low-rate performance of silicone and pulverization and polarization caused by swelling, increasing electrode capacity, and prolonging cycle life. The invention also provides a preparation method of the silicon-based composite negative electrode plate, and a lithium ion secondary battery containing the silicon-based composite negative electrode plate.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to a silicon-based composite negative electrode sheet, a preparation method thereof, and a lithium ion secondary battery. Background technique [0002] Lithium-ion batteries are widely used in portable electronic devices, electric vehicles, and energy storage due to their advantages such as high voltage, high energy density, low self-discharge, long cycle life, and no memory effect. In order to meet the needs of various application scenarios, improving energy density and service life is the main direction of lithium-ion battery development at this stage. [0003] The negative electrode material is an important part of the battery. The theoretical capacity of the current commercial graphite negative electrode material is 372mAh / g, which cannot meet the capacity matching requirements of high-energy positive electrode materials such as lithium-rich materials and nickel-ma...

Claims

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Application Information

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IPC IPC(8): H01M4/134H01M4/1395H01M4/36H01M4/38H01M10/0525
CPCH01M4/134H01M4/1395H01M4/366H01M4/386H01M10/0525H01M4/36H01M4/38Y02E60/10
Inventor 杨婉璐王志勇夏圣安
Owner HUAWEI TECH CO LTD
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