Nano-silicon grinding aid and application thereof

Abstract

The application relates to a nano-silicon grinding aid and application thereof, characterized by the following mass percentage of raw material components: 10.0-20.0% of non-ionic surfactant, 20.0% of oleic acid, 60.0-70.0% of paraffin oil; the non-ionic surfactant is one of fatty alcohol polyoxyethylene ether, alkyl phenol polyoxyethylene ether and fatty acid polyoxyethylene ester or a mixture of any mass ratio thereof. The application of the nano-silicon grinding aid in the preparation of nano-silicon is that 1-3 mass parts of the grinding aid is added in a silicon powder grinding mixture. The application has the advantages that the ball milling efficiency is ensured, and the micro-morphology integrity and size uniformity of the nano-silicon product are improved.

Description

Technical Field

[0001] This invention relates to the field of energy storage materials technology, and in particular to a grinding aid for nano-silicon grinding and its application. Background Technology

[0002] High-purity nano-silicon (nanoSi) is widely used in power batteries, optoelectronic devices, semiconductors, and other fields, thus possessing a broad market and significant economic value. Currently, the main methods for preparing nanoSi include silica reduction, mechanical ball milling, chemical vapor deposition, and plasma evaporation-condensation. Among these, mechanical ball milling has become the fastest-growing technology in recent years due to its low cost.

[0003] Mechanical ball milling is a method that uses mechanical grinding pressure and shearing force to pulverize and grind large-sized silicon materials into nanoSi (nano-silicon) powder. To accelerate the grinding process, ball milling often requires the use of grinding aids. These aids can easily introduce impurities such as water and metal ions, reducing the purity of the nanoSi; they can also cause nanoSi agglomeration, resulting in coarser particles and affecting product uniformity. Therefore, this invention aims to provide a grinding aid for nano-silicon grinding and its application in the nano-silicon grinding process to solve the above-mentioned technical problems. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a grinding aid for nano-silicon grinding and its application. The grinding aid has the advantages of good stability, convenient preparation and low cost, and can improve the microstructure integrity and size uniformity of nano-silicon products.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a grinding aid for nano-silicon grinding, characterized in that: the grinding aid is composed of 10.0-20.0% nonionic surfactant, 20.0% oleic acid and 60.0-70.0% paraffin oil, wherein all percentages are mass percentages.

[0006] The nonionic surfactant is one of fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, fatty acid polyoxyethylene ester, or a mixture thereof in any mass ratio.

[0007] The oleic acid is cis-octadecene-9-acid or linoleic acid or a mixture thereof in any mass ratio.

[0008] The paraffin oil is one of n-docosane and n-octacosane, or a mixture of them in any mass ratio.

[0009] The application of a grinding aid for nano-silicon grinding in the preparation of nano-silicon is characterized by: adding 1 to 3 parts by weight of the grinding aid to the silicon powder grinding mixture; the grinding aid is composed of 10.0 to 20.0 wt.% nonionic surfactant, 20.0 wt.% oleic acid, and 60.0 to 70.0 wt.% paraffin oil; the nonionic surfactant is one of fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, fatty acid polyoxyethylene ester, or a mixture thereof in any mass ratio.

[0010] Furthermore, the grinding aid is mixed with micron-sized silicon powder and dispersant at a mass ratio of (1-3):(10-20):80, and then added to a ball mill chamber for mechanical grinding to prepare nano-silicon products.

[0011] The preferred micron-sized silicon powder is one with a particle size of 1 to 10 μm.

[0012] The dispersant can be ethanol or ethylene glycol, or a mixture of ethanol and tackifying resins such as rosin, terpene resins, polyvinyl alcohol, etc.

[0013] The advantage of the grinding aid described in this invention is that it can improve the microstructure integrity and size uniformity of nano-silicon products while ensuring ball milling efficiency. Attached Figure Description

[0014] Figure 1 This is a particle size distribution diagram of micron-sized silicon raw materials;

[0015] Figure 2 The particle size distribution of nano-silicon products obtained by direct ball milling (without adding grinding aid) of micron-sized silicon raw material for 4 hours is shown.

[0016] Figure 3 This is a particle size distribution diagram of the nano-silicon product obtained in Example 1;

[0017] Figure 4 This is a particle size distribution diagram of the nano-silicon product obtained in Example 2;

[0018] Figure 5 This is a particle size distribution diagram of the nano-silicon product obtained in Example 3;

[0019] Figure 6 This is a microscopic morphology diagram of the nano-silicon product obtained in Example 3. Detailed Implementation

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0021] Example 1: Application of grinding aids for nano-silicon in the preparation of nano-silicon:

[0022] (1) Preparation of grinding aid: Under the condition of uniform stirring, 2.0g of oleic acid was added to 7.0g of paraffin oil. After 10min, a yellow oily liquid was obtained. 1.0g of fatty alcohol polyoxyethylene ether was added to the yellow oily liquid in three portions. The mixture was stirred at 1000r / min for 2.0h to obtain a paste-like grinding aid.

[0023] (2) Take 10.0g of silicon powder with a particle size distribution of 1-10µm, add it to 100mL of ethanol and stir to disperse. Then add 1.0g of the above-mentioned paste-like grinding aid, mix thoroughly, and load it into a planetary ball mill containing agate beads. After ball milling for 2.0h, take out the slurry mixture, centrifuge to separate it into powder, and finally dry it to obtain the nano-silicon product. Figure 3 As shown, the particle size of the obtained nano-silicon products is concentrated in the range of 180 to 850 nm, with a relatively uniform particle size distribution and a consistency of 0.55.

[0024] Example 2: Application of grinding aids for nano-silicon in the preparation of nano-silicon:

[0025] (1) Preparation of grinding aid: Under the condition of uniform stirring, 2.0g of oleic acid was added to 6.0g of paraffin oil, and after 10min, a yellow oily liquid was obtained. 2.0g of alkylphenol polyoxyethylene ether was added to the yellow oily liquid, and stirred at 1000r / min for 1.0h to obtain a paste-like grinding aid.

[0026] (2) Take 3.0g of the paste-like grinding aid and mix thoroughly with 100mL of ethanol. After ultrasonic stirring for 0.5h, a solution is obtained. Then, add 20.0g of micron-sized silicon powder with a particle size of 1-10um to the solution, mix well, and then load it into a planetary ball mill containing agate beads. After ball milling for 4.0h, the slurry mixture is taken out, centrifuged to obtain powder, and finally dried to obtain the nano-silicon product. Figure 4 As shown, the particle size of the obtained nano-silicon products is concentrated in the range of 150 to 500 nm, with uniform particle size distribution and a consistency of 0.36.

[0027] Example 3: Application of grinding aids for nano-silicon in the preparation of nano-silicon:

[0028] (1) Preparation of the grinding aid: Under the condition of uniform stirring, 1.0g of fatty acid polyoxyethylene ester was dissolved in 20.0mL of ethanol; then the ethanol solution was mixed with 1.0g of oleic acid and 3.0g of paraffin oil, and stirred at 1000r / min for 2.0h to obtain the liquid grinding aid.

[0029] (2) Take 2.0g of the liquid grinding aid and mix thoroughly with 80mL of ethanol. After ultrasonic stirring for 20min, a solution is obtained. Then, add 10.0g of silicon powder with a particle size of 1-10um to the solution, mix well, and load it into a planetary ball mill containing agate beads. After ball milling for 4.0h, take out the slurry mixture, centrifuge to obtain powder, and finally dry to obtain nano-silicon product. Figure 5 , Figure 6 As shown, the particle size of the obtained nano-silicon products is concentrated in the range of 150-450 nm, with uniform particle size distribution and a consistency of 0.38. The nano-silicon particles are ellipsoidal in appearance and have a slight agglomeration phenomenon.

Claims

1. A grinding aid for nano-silicon grinding, characterized in that: It is composed of the following raw material components in mass percentage: 10.0-20.0% nonionic surfactant, 20.0% oleic acid, and 60.0-70.0% paraffin oil; wherein the nonionic surfactant is one of fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, and fatty acid polyoxyethylene ester, or a mixture thereof in any mass ratio; wherein the oleic acid is cis-octadecene-9-acid or linoleic acid, or a mixture thereof in any mass ratio; and wherein the paraffin oil is one of n-docosahexadecane and n-octadecane, or a mixture thereof in any mass ratio.

2. The application of a grinding aid for nano-silicon in the preparation of nano-silicon, characterized in that: Add 1-3 parts by weight of a grinding aid to the silicon powder grinding mixture. The grinding aid consists of 10.0-20.0% nonionic surfactant, 20.0% oleic acid, and 60.0-70.0% paraffin oil, all percentages being by weight. The nonionic surfactant is one of fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, or fatty acid polyoxyethylene ester, or a mixture thereof in any mass ratio. The grinding aid is mixed with micron-sized silicon powder and a dispersant at a mass ratio of 1-3:10-20:80, and then added to a ball mill chamber for mechanical grinding to prepare nano-silicon products. The micron-sized silicon powder has a particle size of 1-10 μm. The dispersant is ethanol.

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