Method for preparing boron-doped nano-metal/porous silicon-carbon composite negative electrode based on cut silicon wastes

A technology of nano-metal and porous silicon, which is applied in the direction of nanotechnology, silicon compound, nanotechnology, etc. for materials and surface science, and can solve the problem of silicon material loss and other issues

Active Publication Date: 2020-10-20
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, during the cutting process, about 40% of the high-purity silicon material enters the cutting slurry in the form of "sawdust", resulting in a large amount of silicon material loss

Method used

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  • Method for preparing boron-doped nano-metal/porous silicon-carbon composite negative electrode based on cut silicon wastes
  • Method for preparing boron-doped nano-metal/porous silicon-carbon composite negative electrode based on cut silicon wastes
  • Method for preparing boron-doped nano-metal/porous silicon-carbon composite negative electrode based on cut silicon wastes

Examples

Experimental program
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Embodiment 1

[0030] Example 1: A method for preparing boron-doped nano-metal / porous silicon-carbon composite negative electrodes based on cutting silicon waste, the specific steps are as follows:

[0031] (1) Diamond wire cutting silicon waste is dried, crushed, and ground to obtain waste silicon powder. At room temperature and under stirring conditions, the waste silicon powder is soaked and purified in an alkali-alcohol solution (NaOH-ethanol solution) for 180 minutes. Separate, wash the solid repeatedly with deionized water until the washing liquid is neutral to obtain purified silicon powder; wherein the mass concentration of NaOH in the alkali-alcohol solution (NaOH-methanol solution) is 10%,

[0032] (2) Place the purified silicon powder in step (1) in the HF-metal salt-alcohol solution system (HF-AgNO 3 -methanol solution system) and metal Ag-assisted etching treatment at a temperature of 60°C for 120min, ultrasonically rinsed with deionized water until the washing liquid is neutral...

Embodiment 2

[0037] Embodiment 2: A method for preparing a boron-doped nano-metal / porous silicon-carbon composite negative electrode based on cutting silicon waste, the specific steps are as follows:

[0038] (1) Diamond wire cutting silicon waste is dried, crushed, and ground to obtain waste silicon powder. At room temperature and under stirring conditions, the waste silicon powder is soaked and purified in an alkali-alcohol solution (NaOH-methanol solution) for 150 minutes. Solid-liquid Separation, washing the solid with deionized water several times until the washing liquid is neutral to obtain purified silicon powder; wherein the mass concentration of NaOH in the alkali-alcohol solution (NaOH-methanol solution) is 15%;

[0039] (2) Place the purified silicon powder in step (1) in the HF-metal salt-alcohol solution system (HF-CuNO 3 -methanol solution system) and at a temperature of 60°C, metal Cu-assisted etching treatment was carried out for 120 min, ultrasonically rinsed with deioniz...

Embodiment 3

[0044] Embodiment 3: A method for preparing boron-doped nano-metal / porous silicon-carbon composite negative electrode based on cutting silicon waste, the specific steps are as follows:

[0045] (1) Diamond wire cutting silicon waste is dried, crushed, and ground to obtain waste silicon powder. At room temperature and under stirring conditions, the waste silicon powder is soaked and purified in an alkali-alcohol solution (NaOH-methanol solution) for 200 minutes. Separation, washing the solid with deionized water several times until the washing liquid is neutral to obtain purified silicon powder; wherein the mass concentration of NaOH in the alkali-alcohol solution (NaOH-methanol solution) is 20%;

[0046] (2) Put the purified silicon powder in step (1) in the HF-metal salt-alcohol solution system (HF-NiNO 3 -methanol solution system) at a temperature of 70° C. for 100 minutes of metal Ni-assisted etching treatment, ultrasonically rinsed with deionized water until the washing li...

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Abstract

The invention relates to a method for preparing a boron-doped nano-metal/porous silicon-carbon composite negative electrode based on cut silicon wastes. The method comprises the following steps: removing impurities from cut silicon wastes, and carrying out metal-assisted etching treatment to obtain a nano-metal/porous silicon composite material; mixing the nano-metal/porous silicon composite material with a boron source, and carrying out high-temperature treatment to form substitution doping of silicon by boron; compounding with a carbon material to obtain the boron-doped nano-metal/porous silicon-carbon composite negative electrode. By adding the porous structure of silicon and the carbon material, the volume expansion of silicon can be relieved and cycling stability is increased; the metal particles are physically compounded with silicon on the surface of the silicon substrate, and the boron has the chemical doping synergistic effect of silicon on the atomic scale, so that the intrinsic conductivity of the silicon-based composite material and the electrochemical activity are finally improved, and the boron-doped nano-metal/silicon-carbon composite negative electrode material withhigh charge-discharge specific capacity and long cycle life is prepared.

Description

technical field [0001] The invention relates to a method for preparing a boron-doped nanometer metal / porous silicon-carbon composite negative electrode based on cutting silicon waste, and belongs to the field of new energy materials and electrochemical technology. Background technique [0002] At present, most commercial lithium-ion batteries still use graphite materials as negative electrode materials. Graphite materials have good cycle stability, but low specific capacity. Silicon-based anode material with high safety, 4200mAhg -1 The theoretical capacity makes the upper limit of its development very high. However, silicon will produce a very serious volume effect (>300%) during the lithiation process, which will cause the silicon material to be crushed during the charge-discharge cycle and form an unstable solid electrolyte. Interfacial film, which leads to rapid decay of electrode capacity. At present, most of these problems for silicon negative electrodes are solve...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/38H01M4/62H01M10/0525C01B33/037C01B32/00B82Y40/00B82Y30/00
CPCH01M4/386H01M4/626H01M4/625H01M10/0525C01B32/00C01B33/037B82Y30/00B82Y40/00Y02E60/10
Inventor 李绍元王雷马文会席风硕张钊万小涵魏奎先陈正杰于洁伍继君谢克强杨斌戴永年
Owner KUNMING UNIV OF SCI & TECH
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