Porous silicon material, and preparation method and application thereof

A technology of porous silicon and anode materials, applied in the field of material science, can solve the problems of low intrinsic conductivity of silicon, low first Coulomb efficiency, limited practical application, etc., to achieve good battery cycle stability, easy process control, suitable for large-scale The effect of mass production

Active Publication Date: 2015-11-11
NINGBO INST OF MATERIALS TECH & ENG CHINESE ACADEMY OF SCI
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  • Abstract
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the researchers found that the silicon-based negative electrode material will undergo a serious volume change (volume expansion of more than 300%) during the process of lithium intercalation and deintercalation. Due to the volume change, problems such as electrode powdering and peeling will lead to a sharp decline in performance and poor cycle performance.
At the same time, the first coulombic efficiency of silicon-based negative electrode materials is also low, and the intrinsic conductivity of silicon is low, so the formed SEM is unstable and easy to fall off.
These disadvantages limit its practical application in Li-ion batteries
In addition, the preparation process for preparing high-performance silicon-based anode materials is relatively complicated and the preparation cost is also high.

Method used

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  • Porous silicon material, and preparation method and application thereof
  • Porous silicon material, and preparation method and application thereof
  • Porous silicon material, and preparation method and application thereof

Examples

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preparation example Construction

[0053] Preparation method of porous silicon negative electrode active material

[0054] The preparation method of the porous silicon negative electrode active material includes: ultrasonic chemical method, wet chemical method, mechanochemical reaction (such as mechanical alloying method and mechanical ball milling method) and the like.

[0055] In a preferred embodiment, a method for preparing a porous silicon negative electrode active material includes: using a metallurgical iron-silicon alloy as a raw material, preparing the target product through mechanical ball milling and acid etching.

[0056] In a more specific embodiment, the preparation method may include the following steps:

[0057] (i) metallurgical iron-silicon materials that provide silicon sources;

[0058] (ii) ball milling the iron-silicon alloy;

[0059] (iii) performing metal-assisted acid etching of the iron-silicon alloy in an acid etching reagent to prepare a porous silicon material.

[0060] In a prefer...

Embodiment 1

[0142] Preparation of Example 1 Porous Silicon Negative Active Material (i.e. "porous silicon material"):

[0143] 1) Weigh 2g of metallurgical iron-silicon alloy, 2g of absolute ethanol and 16g of agate balls, and add them to a 100ml agate ball mill jar respectively.

[0144] 2) Put the ball mill jar into the ball mill, set the ball mill parameters, the speed is 300r / min, the working time is 24 hours, and every 20 minutes of work is 10 minutes of rest.

[0145] 3) Suction filtration, washing and drying of the ball-milled small particles of iron-silicon alloy.

[0146] 4) Measure 100ml of 2M hydrochloric acid solution into a 200ml beaker, slowly add small grains of iron-silicon alloy, and keep stirring until the addition is complete. Put the beaker into an ultrasonic instrument for ultrasonic dispersion for 30min. Remove the beaker and place it on a magnetic stirrer for 24 h of continuous stirring. Suction filtration and drying.

[0147] 5) Add the sample treated with hydr...

Embodiment 2

[0158] Preparation of Example 2 Porous Silicon Negative Active Material:

[0159] 1) Weigh 2g of metallurgical iron-silicon alloy, 1g of absolute ethanol and 8g of agate balls in an argon atmosphere, and add them to a 100ml agate ball mill jar.

[0160] 2) Put the ball mill pot into the ball mill, set the ball mill parameters, the speed is 400r / min, the working time is 12h, and every 10min of work is 10min of rest.

[0161] 3) Suction filtration, washing and drying of the ball-milled small particles of iron-silicon alloy.

[0162] 4) Measure 100ml of 10% hydrofluoric acid solution into a 200ml plastic beaker, slowly add small grains of iron-silicon alloy, and keep stirring until the addition is complete. Put the beaker into an ultrasonic instrument for ultrasonic dispersion for 30min. Remove the beaker and place it on a magnetic stirrer for 12 h of continuous stirring. Suction filtration, washing and drying to prepare porous silicon material.

[0163] The porous silicon mate...

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Abstract

The invention discloses a porous silicon material, and a preparation method and an application thereof. The porous silicon material is mainly prepared by mechanical milling and acid etching of metallurgical iron-silicon alloy as a raw material; the dimension of the porous silicon material is in micron/submicron level; the porous silicon material has a diamond structure, belongs to an Fd-3m (227) space group, and has a reaction phase which can react with lithium (Li); a large number of hierarchical porous structures with different dimensions are evenly distributed in the surface and the inside of the porous silicon material; the porous silicon material can be used as a lithium ion battery anode active material, and shows the characteristics of high (first) coulombic efficiency, high capacity, excellent cycling stability and the like when applied to a lithium ion battery; meanwhile, the preparation technology of the porous silicon material is simple, and can be carried out only by conventional equipment; the used raw materials are cheap and available; the technological process is easy to control; and the porous silicon material is good in repeatability, high in productivity, stable in product quality and suitable for large-scale production.

Description

technical field [0001] The present invention particularly relates to a porous silicon material and its preparation method and application, such as its use as a high coulombic efficiency porous silicon negative electrode active material and / or its application in batteries, especially lithium-ion batteries, belonging to the field of material science. Background technique [0002] Environmental pollution and climate change are major problems in the 21st century. In order to solve this problem, governments of various countries have invested a lot of energy in developing new energy industries, such as: solar energy, wind energy, tidal energy and so on. Lithium-ion battery, as a reliable means of energy storage, has been a research hotspot since its inception. At present, the commercial lithium-ion battery anode materials use carbon materials, which have the advantages of high cycle efficiency, long cycle life, and low electrode potential. With the gradual clarification of the hu...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/38C01B33/021H01M10/0525
CPCH01M4/386H01M10/0525Y02E60/10
Inventor 田华军何伟韩伟强
Owner NINGBO INST OF MATERIALS TECH & ENG CHINESE ACADEMY OF SCI
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