Silicon-based 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, circuits, etc., can solve the problems of low reversible specific capacity of amorphous silicon, improve cycle stability, facilitate industrial production, and have good crack resistance. Effect

Active Publication Date: 2017-01-04
HEFEI GUOXUAN HIGH TECH POWER ENERGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the reversible specific capacity of amorphous silicon is on the low side (Journal of Power Sources magazine, 2003, Volume 115, page 346), so those skilled in the art are committed to developing a method that can improve the cyclic stability of silicon and fully utilize it. A new type of material with lithium storage capacity of silicon, and its preparation process is simple, easy to achieve large-scale production

Method used

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  • Silicon-based lithium ion battery negative electrode material and preparation method thereof
  • Silicon-based lithium ion battery negative electrode material and preparation method thereof
  • Silicon-based lithium ion battery negative electrode material and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] Preparation of negative electrode materials for silicon-based lithium-ion batteries: At room temperature, add amorphous silicon particles into hydrofluoric acid solution with a molar concentration of 30mol / L, stir for 0.5h, then wash the product with deionized water, and collect the product by centrifugation ; Vacuum drying, the drying temperature is 40 ° C, the dried product is spread in a refractory container corundum porcelain boat, sintered at 650 ° C for 4 hours in an argon atmosphere, and the amorphous silicon-coated single crystal silicon can be obtained after cooling. composite material.

[0031] figure 1 It is a structural diagram of the silicon-based lithium-ion battery anode material obtained in Example 1, in which single crystal silicon (black) is embedded in an amorphous silicon matrix (gray).

[0032] figure 2 It is the X-ray diffraction pattern of the silicon-based lithium-ion battery negative electrode material obtained in Example 1. The peak type can...

Embodiment 2

[0040]Negative electrode material preparation of silicon-based lithium-ion battery negative electrode material: Add amorphous silicon bulk material to 0.1mol / L sodium hydroxide solution at room temperature, let it stand for 5h, then wash the product with deionized water, and collect it by sedimentation product, remove the sodium hydroxide solution; blow dry with nitrogen, spread the dried product in a corundum porcelain boat in a refractory container, sinter at 500°C for 1h under an argon atmosphere, and obtain amorphous silicon-coated single crystal silicon after cooling block composites.

[0041] Image 6 The X-ray diffraction pattern of the silicon-based lithium-ion battery negative electrode material prepared in Example 2, the peak type can be compared with JCPDS 27-1402, and it is found that there are two broad peaks at 28° and 50°, which are speculated to be amorphous diffraction peaks of silicon ; and there are two narrow peaks at 47° and 56°, indicating the presence o...

Embodiment 3

[0044] Silicon-based lithium-ion battery anode material Anode material preparation: Add amorphous silicon wire to 1mol / L hydrofluoric acid solution at room temperature, stir for 1 hour, then wash the product with deionized water, collect the product by centrifugation; vacuum dry, The drying temperature is 100°C, spread the dried product in a corundum porcelain boat (other refractory containers can be used instead of the corundum porcelain boat), sinter at 1000°C for 10 hours in a neon atmosphere, and obtain amorphous silicon-coated single crystal after cooling Linear composites of silicon.

[0045] Figure 8 It is the X-ray diffraction pattern of the silicon-based lithium-ion battery negative electrode material prepared in Example 3. The peak type can be compared with JCPDS 27-1402. The peak type in the figure is narrower and the peak intensity is stronger, indicating that the crystallinity of silicon becomes higher.

[0046] Figure 9 The high-magnification TEM electron mic...

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Abstract

The invention discloses a silicon substrate lithium ion battery negative electrode material and a preparation method thereof. The negative electrode material comprises an amorphous silicon substrate and a plurality of monocrystalline silicon cores, wherein the monocrystalline silicon cores are embedded in the amorphous silicon substrate and are covered by the amorphous silicon. The preparation method comprises the following steps: firstly, removing a silicon oxide layer on the outer surface of the amorphous silicon by adopting a chemical etching method; calcining the amorphous silicon material at high temperature under inert atmosphere; realizing the nucleation and growth of monocrystalline silicon in the amorphous silicon material; controlling the calcining time and the calcining temperature, thereby realizing the regulation for the inner silicon core size. The first specific discharge capacity of the compound material is above 1500mAh/g and the specific discharge capacity after 35 times of repeated charging and discharging circulation still can be kept above 1150mAh/g.

Description

technical field [0001] The invention relates to a lithium ion battery material, in particular to a silicon-based lithium ion battery negative electrode material and a preparation method thereof. Background technique [0002] With the development of electric vehicles and portable electronic products, lithium-ion secondary batteries have high specific energy, high working voltage, high energy density, long cycle life, small self-discharge, no pollution, light weight, good safety, etc. Advantages, since it was put into the market in 1990, it has developed rapidly, and now it has occupied the mainstream of the market, and its application is becoming more and more extensive. The current commercial lithium-ion battery anode material is a carbon-based anode material, but its theoretical capacity is only 372mAh / g, and it has been developed close to the theoretical value. In order to meet the needs of high-capacity lithium-ion batteries, research and development of high-capacity lith...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/38H01M10/0525
CPCH01M4/366H01M4/386H01M10/0525Y02E60/10
Inventor 孙壮林少雄张成龙王辉杨学兵
Owner HEFEI GUOXUAN HIGH TECH POWER ENERGY
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