WO2018205761A1 - Method for preparing three-dimensional porous silicon by taking silicate glass as raw material - Google Patents

Method for preparing three-dimensional porous silicon by taking silicate glass as raw material Download PDF

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WO2018205761A1
WO2018205761A1 PCT/CN2018/080752 CN2018080752W WO2018205761A1 WO 2018205761 A1 WO2018205761 A1 WO 2018205761A1 CN 2018080752 W CN2018080752 W CN 2018080752W WO 2018205761 A1 WO2018205761 A1 WO 2018205761A1
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porous silicon
magnesium
silicate glass
porous
reaction
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霍开富
高标
安威力
梅世雄
付继江
张旭明
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武汉科技大学
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    • C01B33/00—Silicon; Compounds thereof
    • C01B33/02—Silicon
    • C01B33/021—Preparation
    • H—ELECTRICITY
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    • H01M4/36—Selection of substances as active materials, active masses, active liquids
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    • H01M4/386—Silicon or alloys based on silicon
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    • H01M2004/027—Negative electrodes
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    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the invention belongs to the field of nano materials, and more particularly to a method for preparing three-dimensional porous silicon from silicate glass.
  • Silicon is the second largest content (about 26.4%) of the earth's crust. As a common semiconductor material, it has become an indispensable technical foundation for modern high-tech society. Elemental silicon has a wide range of important applications in energy, semiconductor, organic silicon and metallurgical industries. At present, the anode materials of mature commercial lithium-ion batteries are mainly graphite-based carbon materials, but the theoretical lithium storage capacity of carbon materials is only 372 mA h/g, which cannot meet the demand for high-energy density materials. Silicon has the negative electrode material for lithium-ion batteries.
  • the preparation methods of silicon nanomaterials mainly include physical methods and chemical methods.
  • Physical methods mainly include pulverization method, mechanical alloying method, evaporative condensation method, etc.
  • chemical methods mainly include gas phase precipitation method, magnesium thermal reduction method, wet chemical reduction aerosol Law and so on.
  • these methods for preparing silicon nanomaterials are not only harsh, expensive, complicated, and have serious pollution, involve many toxic substances, and are harmful to humans.
  • the copper-based catalyst and silicon are used in the literature "Carbon-coated porous silicon composites as high performance Li-ion battery anode materials: can the production process be cheaper and greener" (J. Mater. Chem. A, 2016, 4, 552-560).
  • the particles are hydrothermally heated in anhydrous ethanol at 200 ° C, and the hydrothermal product is treated with nitric acid to obtain porous silicon.
  • This method is cumbersome, and the hydrothermal risk coefficient of anhydrous ethanol at 200 ° C is quite large, which is not suitable for wide application.
  • the nano-silicon is prepared by magnesium thermal reduction and adding sodium chloride molten salt. Since the main component in the quartz glass is silica, the silica in the quartz glass has good crystallinity, the melting point is up to 1400 ° C, and the energy required for the reaction is more. Large, long reaction time, the obtained nano-silicon has no special three-dimensional structure, and there are many magnesium silicides as by-products, resulting in low yield, uneven particle size distribution, and volume expansion during the lithium insertion process of the negative electrode material. To achieve effective mitigation, electrochemical performance is not ideal. Because these raw materials react with magnesium as a "solid-liquid" reaction, the morphology of the prepared silicon is similar to that of the raw material.
  • nano-silicon does not form a whole, when the volume expands. The separation between the particles leads to the loss of good electrical contact, and finally the electrons cannot be effectively transported, the capacity is accelerated, and the rate performance is poor.
  • the molten salt mainly uses non-magnesium molten salt systems such as NaCl and KCl.
  • these molten salts do not promote the magnesium thermal reaction well, and the molten metal magnesium in the molten state cannot be obtained during the reaction. It is well infiltrated with these molten salts, resulting in insufficient contact reaction between magnesium and the reactants, thus requiring a longer reaction time and more magnesium, and the purity of the product is not high.
  • nano-silicon can solve the problem of volume expansion, most of the nano-silicon porous is mainly composed of many nano-silicon particles. Nano-silicon does not form a whole. When the volume expands, the separation between particles will lose good. Electrical contact eventually leads to inefficient transmission of electrons, accelerated capacity reduction, and poor rate performance. Both require complex carbon-coated nano-silicon to solve this problem, increase cost and process, and cannot be widely promoted.
  • the high surface activation energy of the nanoparticles leads to low tap density of the electrode material, so that the energy of the electrode material of the unit volume is low, thereby causing the battery to be too bulky and affecting widespread use.
  • the present invention provides a three-dimensional porous silicon and a preparation method and application thereof, the object of which is to use a silicate glass as a raw material, a magnesium halide as a molten salt, and a low temperature.
  • the nanoporous silicon is prepared by the magnesium thermal reduction reaction, thereby solving the prior art nano silicon preparation method, the conditions are harsh, the cost is high, the steps are complicated, and the pollution is serious.
  • the prepared nano silicon agglomeration phenomenon is serious, the by-products are many, and the porous structure exists only.
  • the technical problems such as the application requirements of the negative electrode material of the battery cannot be satisfied between the silicon particles and the low volume energy density.
  • a porous silicon particle having a particle diameter ranging from 1 to 5 ⁇ m, the porous silicon particle having a three-dimensionally penetrating pore structure therein,
  • the size of the macroporous structure in the pore structure is 50 to 200 nm, and the size of the mesoporous structure is 2 to 6 nm.
  • the porous silicon particles have a specific surface area of 270 to 380 m 2 g -1 .
  • the porous silicon particles have a tap density of 0.76 to 0.835 g/cm 3 .
  • a method for preparing a three-dimensional porous micron silicon wherein the powdered silicate-based glass, the magnesium powder and the molten salt are in a mass ratio of 1: (0.5 to 0.8): (5 to 8) After mixing uniformly, the mixture is heated at 605 to 750 ° C for 1 to 12 hours at a temperature increase rate of 1 to 10 ° C / min, and then pickled to obtain porous micro silicon.
  • the silicate glass is sodium silicate glass or calcium silicate glass.
  • the molten salt is a magnesium halide.
  • the molten salt is magnesium chloride, magnesium bromide or magnesium iodide.
  • the molten salt is magnesium chloride.
  • the preparation method comprises the following steps:
  • step (3) The mixture obtained in the step (2) is heated at a temperature increase rate of 1 to 10 ° C / min to 605 to 750 ° C for 1 to 12 hours to obtain a mixture after the reaction;
  • the pickling step is specifically: washing in 1 mol/L hydrochloric acid under stirring for 1-8 h, then washing in 0.1 mol/L hydrofluoric acid, and drying to obtain porous micron silicon particles.
  • porous silicon particles described above for use in a lithium ion battery negative electrode material.
  • the raw material used for preparing porous silicon of the invention is silicate glass, the raw material source is wide, the synthesis method is simple and easy, the cost is low, the yield purity is high, the large-scale production can be carried out, and the raw materials can also be recycled and recycled;
  • the raw material silicate glass is in a molten state at 605 ° C ⁇ 750 ° C, this temperature is also in the reaction temperature range and the magnesium powder is also in a liquid state, which is a "liquid-liquid” magnesium thermal reaction superior to other "solid”
  • the liquid “magnesium thermal reaction” facilitates the reaction to proceed sufficiently and obtains a stable, uniformly distributed three-dimensional porous structure
  • a metal salt of magnesium such as magnesium chloride, magnesium bromide or magnesium iodide is used as a molten salt. Since the melting point of these molten salts is also between 605 and 750 ° C, on the one hand, the reaction environment is stabilized and The heat absorbing agent avoids agglomeration and sintering of the product, and on the other hand, because the magnesium salt has better solubility to the magnesium powder in the molten state and better wettability to the reactant, the whole reaction is more suitable and the reaction is more complete. The energy required for the reaction is lower and the overall reaction is safer;
  • the three-dimensional porous silicon prepared by the invention has the advantages of the negative electrode material of the lithium ion battery: the porous structure can not only facilitate the contact of the electrolyte but also alleviate the volume expansion during the process of intercalating lithium, and the three-dimensional porous structure is also beneficial to the electrode material.
  • the reaction is inwardly expanded to ensure that the thickness of the electrode film is kept stable, and the safety of the current lithium ion battery is greatly improved; in addition, the three-dimensional through structure is more advantageous for lithium ion transmission, and has wide application prospects.
  • the micron-scale size has a large tap density to increase the energy density per unit volume of the electrode.
  • the tap density of the porous micro-silica prepared by the present invention is 0.81 g/cm 3
  • the tap density of commercially available nano-silicon is only It is 0.15 g/cm 3 .
  • the steps of the preparation method of the porous micron silicon of the present invention cooperate to form an independent technical scheme, and the excellent porous micro silicon is prepared.
  • the invention selects the silicate-based glass as the raw material and the magnesium halide as the molten salt. Since the two are in a molten state between 605 and 750 ° C, the molten state reaction can be realized, and good mass transfer is achieved, and silicon is obtained.
  • the acid-based glass itself contains symbiotic impurities such as sodium, calcium, magnesium and aluminum, and the molten-melting molten salt skeleton penetrates through it. With this unique advantage, the porous reaction micro-silicon is obtained by pickling the reaction product. structure.
  • Example 1 is a scanning electron micrograph of three-dimensional porous silicon prepared in Example 1 of the present invention.
  • Example 2 is an XRD pattern of the three-dimensional porous silicon prepared in Example 1 of the present invention.
  • Example 3 is a transmission electron micrograph of the three-dimensional porous silicon prepared in Example 1 of the present invention.
  • Example 4 is a graph showing electrochemical cycle performance of three-dimensional porous silicon prepared in Example 1 of the present invention.
  • Example 5 is a graph showing adsorption and desorption curves and pore size distribution curves of three-dimensional porous silicon prepared in Example 1 of the present invention.
  • the porous silicon particles provided by the present invention have a particle size ranging from 1 to 5 micrometers, and the porous micron silicon particles have a three-dimensionally penetrating pore structure therein, and the macroporous structure size of the pore structure is 50 to 200 nm, and the mesoporous structure The size is 2 to 6 nm.
  • the porous silicon particles have a specific surface area of 270 to 380 m 2 g -1 .
  • the porous silicon particles have a tap density of 0.76 to 0.835 g/cm 3 .
  • the method for preparing the three-dimensional porous micron silicon is: mixing the powdered silicate-based glass, the magnesium powder and the molten salt according to a mass ratio of 1: (0.5-0.8): (5-8), and then 1 to 10 ° C / The heating rate of min is heated to 605-750 ° C for 1-12 h, and then pickled to obtain porous micron silicon.
  • the silicate glass is sodium silicate glass or calcium silicate glass.
  • the molten salt is a magnesium halide, including magnesium chloride, magnesium bromide or magnesium iodide, preferably magnesium chloride.
  • the preparation method includes the following steps:
  • step (3) The mixture obtained in the step (2) is heated at a temperature increase rate of 1 to 10 ° C / min to 605 to 750 ° C for 1 to 12 hours to obtain a mixture after the reaction;
  • the silicate glass powder, the magnesium powder, the molten salt (MgCl 2 ) are ball milled uniformly in a mass ratio of 1:0.6:6; then the mixture is placed in a tube furnace at 5 ° C/min. The heating rate is heated to 650 ° C for 3 h, and the product is taken out after cooling to room temperature with the furnace; the selection of magnesium powder and coal tar ensures that the reaction completely obtains nano-silicon carbide to reduce by-products, and the amount of MgCl 2 can ensure sufficient reaction.
  • the molten medium can be calculated by reaction enthalpy to obtain an appropriate endothermic effect to prevent particle sintering agglomeration.
  • the heating rate is preferably 5 ° C / min, which not only ensures a short reaction time but also ensures a more stable porous structure of the product.
  • the reaction temperature is preferably 650 ° C. On the one hand, close to the melting point of magnesium powder (649 ° C) to ensure the molten state of the magnesium powder reaction, the reaction contact is more sufficient, on the other hand, the silicate glass is also in a molten state at this temperature, which is more favorable for the maintenance of the porous structure. .
  • the pickling step is specifically: washing and stirring in 1 mol/L hydrochloric acid for 1-8 h and then washing in 0.1 mol/L hydrofluoric acid for 10 min to 30 min, and drying to obtain porous silicon nanoparticles.
  • porous silicon particles prepared by the invention can be applied to a lithium ion battery anode material.
  • the invention provides a method for preparing three-dimensional porous silicon by using silicate-based glass as a raw material, comprising the steps of: grinding glass, and then reducing the particle size of the glass by mechanical ball milling to remove the glass powder and the magnesium powder.
  • M is one of Na, Ca, Mg and Al.
  • One or more kinds, and then the reaction product is pickled to obtain three-dimensional porous silicon.
  • the silicate glass having a melting point near the reaction temperature is selected as the raw material, which can ensure the sufficient reaction and the three-dimensional porous structure with stable structure.
  • Ordinary silicate-based glass is characterized by being in a molten state at 605-750 ° C.
  • the magnesium powder is also in a molten state during the reaction, ensuring an excellent "liquid-liquid” reaction, which is beneficial to the sufficient contact and rapid contact of the raw material with the liquid Mg.
  • Mass transfer process liquid-liquid reaction relative to solid-liquid or solid-solid reaction, system temperature and composition are more uniform, porous structure is more stable, basic oxide Na 2 O, CaO, reaction product MgO and molten salt existing after ordinary glass reaction
  • the skeleton structure remains in the form of three-dimensional through-grain in the particles of the product silicon, and the porous micro-silicon having a three-dimensional through-hole structure inside the silicon particles can be obtained by removing the skeleton structure after pickling.
  • the invention adopts magnesium chloride (MgCl 2 ), magnesium bromide (MgBr 2 ) and magnesium iodide (MgI 2 ) as the molten salt to control the reaction temperature below 800 ° C by melting endotherm, so that the whole reaction is under relatively mild conditions. Properly carried out, the energy required for the reaction is lower and the agglomeration sintering of the nanoparticles can be solved.
  • the choice of molten salt is different from the above traditional molten salt system (NaCl, KCl system) is an innovative molten salt system.
  • the industrial and domestic waste silicate-based glass used in the present invention is rich in source and simple to obtain relative to other silicon-containing minerals, and uses the existing waste to obtain nano-silicon by low-temperature magnesia reduction reaction.
  • the prepared three-dimensional porous silicon has the characteristics of high purity, large specific surface area, uniform particles and mesopores, and can be applied to the field of anode materials for lithium ion batteries.
  • the mixture is placed in a tube furnace and heated at 650 ° C for 3 h at a heating rate of 5 ° C / min, and the product is taken out after being cooled to room temperature with the furnace;
  • the silicon prepared in this embodiment belongs to a three-dimensional porous structure of silicon of the order of 1 to 5 micrometers, and an enlarged view shows a porous structure having a distinct three-dimensional penetration inside the silicon particles.
  • the three-dimensional porous silicon prepared in this embodiment has an excellent pore structure and no damage to the overall structure, and the macropore pore diameter is 50 to 200 nm.
  • the porous silicon shown in Fig. 4 has excellent electrochemical cycle performance, has a high capacity after 100 cycles, and has good cycle stability, so that the present invention can be industrially produced and applied on a large scale.
  • the porous silicon has a specific surface area of 380 m 2 g -1 and a mesoporous pore diameter of 2 to 6 nm.
  • the tested micron porous silicon tap density of 0.81g / cm 3, this method of synthesizing the porous silicon having a super high specific surface area and excellent pore structure, suitable for a negative electrode material for a lithium battery.

Abstract

A method for preparing three-dimensional porous silicon by taking silicate glass as a raw material, comprising the following steps: mechanically milling silicate glass into powder; uniformly mixing the powder with magnesium powder and fused salt according to a certain ratio to undergo a reaction in an environment of inert gas; and acid-cleaning the reaction product to obtain three-dimensional porous silicon. Steps of the method are simple and easy to operate, include a wide range of raw materials, and facilitate formation of the three-dimensional porous silicon with a stable structure after reaction in a molten state. The prepared three-dimensional porous silicon has high purity, a large specific surface area, a uniform size of particles, has a mesoporous, and can be applied in the field of negative electrode materials of lithium ion batteries.

Description

一种以硅酸盐玻璃为原料制备三维多孔硅的方法Method for preparing three-dimensional porous silicon by using silicate glass as raw material [技术领域][Technical field]
本发明属于纳米材料领域，更具体地，涉及一种以硅酸盐玻璃为原料制备三维多孔硅的方法。The invention belongs to the field of nano materials, and more particularly to a method for preparing three-dimensional porous silicon from silicate glass.
[背景技术][Background technique]
硅是地壳中第二大含量(约为26.4％)的元素。它作为一种常见的半导体材料，已经成为现代高科技社会不可或缺的重要技术基础,单质硅在能源、半导体、有机硅以及冶金工业等方面有着广泛而重要的应用。目前成熟商业锂离子电池的负极材料主要为石墨类碳材料，但碳材料的理论储锂容量仅为372mA h/g，无法满足人们对高能量密度材料的需求，硅作为锂离子电池负极材料具有很高的理论容量(约4200mA h/g)，十倍于商业用石墨烯的容量，在能量存储方面具有非常大的前景，但是硅负极材料脱嵌锂过程中体积膨胀较大(>300％)，高的体积变化效应导致其较差的循环稳定性，使其距离实用化有一定的距离。Silicon is the second largest content (about 26.4%) of the earth's crust. As a common semiconductor material, it has become an indispensable technical foundation for modern high-tech society. Elemental silicon has a wide range of important applications in energy, semiconductor, organic silicon and metallurgical industries. At present, the anode materials of mature commercial lithium-ion batteries are mainly graphite-based carbon materials, but the theoretical lithium storage capacity of carbon materials is only 372 mA h/g, which cannot meet the demand for high-energy density materials. Silicon has the negative electrode material for lithium-ion batteries. High theoretical capacity (about 4200mA h/g), ten times the capacity of commercial graphene, has great prospects in energy storage, but the bulk expansion of silicon anode material during lithium deintercalation is large (>300%). ), the high volume change effect results in its poor cycle stability, making it a certain distance from practical use.
超细多孔纳米硅，包括多孔纳米硅和多孔微米硅，小尺寸效应可以有效的减弱体积膨胀的应力，还避免一定的容量衰减，多孔结构也可以留下空间缓解膨胀，具有一定的应用前景。目前硅纳米材料的制备方法主要有物理法和化学法，物理法主要包括粉碎法、机械合金化法、蒸发冷凝法等；化学法主要包括气相沉淀法、镁热还原法、湿化学还原气溶胶法等。但是目前这些制备硅纳米材料的方法，不仅条件苛刻、成本昂贵，步骤复杂，而且污染严重、涉及很多有毒物质、对人危害性较大。例如文献“Carbon-coated porous silicon composites as high performance Li-ion battery anode materials:can the production process be cheaper and greener”(J.Mater.Chem.A,2016,4,552-560)中用铜基催化剂和硅颗粒在无水乙醇中在200℃ 的条件下水热，水热产物用硝酸处理得到多孔硅，这种方法步骤繁琐，而且无水乙醇在200℃水热危险系数相当大，不适合广泛应用。Ultra-fine porous nano-silicon, including porous nano-silicon and porous micro-silicon, small size effect can effectively reduce the volume expansion stress, but also avoid a certain capacity attenuation, porous structure can also leave space to ease expansion, has a certain application prospect. At present, the preparation methods of silicon nanomaterials mainly include physical methods and chemical methods. Physical methods mainly include pulverization method, mechanical alloying method, evaporative condensation method, etc.; chemical methods mainly include gas phase precipitation method, magnesium thermal reduction method, wet chemical reduction aerosol Law and so on. However, at present, these methods for preparing silicon nanomaterials are not only harsh, expensive, complicated, and have serious pollution, involve many toxic substances, and are harmful to humans. For example, the copper-based catalyst and silicon are used in the literature "Carbon-coated porous silicon composites as high performance Li-ion battery anode materials: can the production process be cheaper and greener" (J. Mater. Chem. A, 2016, 4, 552-560). The particles are hydrothermally heated in anhydrous ethanol at 200 ° C, and the hydrothermal product is treated with nitric acid to obtain porous silicon. This method is cumbersome, and the hydrothermal risk coefficient of anhydrous ethanol at 200 ° C is quite large, which is not suitable for wide application.
通过镁热还原并加入氯化钠熔盐来制备纳米硅,由于石英玻璃中的主要成分是二氧化硅，石英玻璃中二氧化硅结晶性较好，熔点高达1400℃以上，反应所需能量更大，反应时间较长，得到的纳米硅没有特殊的三维结构，副产物硅化镁有较多，导致产率不高，颗粒堆积明显大小不均，作为负极材料嵌锂过程中体积膨胀仍得不到有效缓解，电化学性能也不是很理想。因为这些原料与镁反应是一种“固-液”反应，制备出来硅的形貌跟原料形貌相似仅仅是纳米颗粒堆积出来的多孔结构，纳米硅并没有形成一个整体，当体积膨胀时会导致颗粒间的分离失去良好的电接触，最终导致电子无法有效的传输，容量减弱加速，倍率性能较差。The nano-silicon is prepared by magnesium thermal reduction and adding sodium chloride molten salt. Since the main component in the quartz glass is silica, the silica in the quartz glass has good crystallinity, the melting point is up to 1400 ° C, and the energy required for the reaction is more. Large, long reaction time, the obtained nano-silicon has no special three-dimensional structure, and there are many magnesium silicides as by-products, resulting in low yield, uneven particle size distribution, and volume expansion during the lithium insertion process of the negative electrode material. To achieve effective mitigation, electrochemical performance is not ideal. Because these raw materials react with magnesium as a "solid-liquid" reaction, the morphology of the prepared silicon is similar to that of the raw material. It is only a porous structure in which nanoparticles are deposited. The nano-silicon does not form a whole, when the volume expands. The separation between the particles leads to the loss of good electrical contact, and finally the electrons cannot be effectively transported, the capacity is accelerated, and the rate performance is poor.
值得注意的是，由于镁热还原过程中会放出大量的热，使材料局部温度达到1700℃以上，进而使得前驱物纳米颗粒团聚成块体，难以保持原始形貌，最终得到的产物也是团聚在一起的大块材料。例如专利“用稻壳生产纳米硅的方法”(CN104030290A)中在没有熔盐存在的情况下制备得到的纳米硅就存在严重的团聚现象。熔盐法可有效解决团聚问题，目前熔盐主要采用NaCl、KCl等非镁的熔盐体系，然而这些熔盐并不能很好的促进镁热反应，反应过程中熔融态的还原剂金属镁无法与这些熔盐很好的浸润互溶，导致镁与反应物无法充分的接触反应，因而需要更长的反应时间和更多镁的量，而且产物纯度不高。It is worth noting that due to the large amount of heat released during the thermal reduction of magnesium, the local temperature of the material reaches above 1700 °C, which causes the precursor nanoparticles to agglomerate into a bulk, which makes it difficult to maintain the original morphology, and the final product is also agglomerated. Large pieces of material together. For example, in the patent "Method for Producing Nano-Silicon from Rice Husk" (CN104030290A), there is a serious agglomeration phenomenon in the preparation of nano-silicon in the absence of molten salt. The molten salt method can effectively solve the agglomeration problem. At present, the molten salt mainly uses non-magnesium molten salt systems such as NaCl and KCl. However, these molten salts do not promote the magnesium thermal reaction well, and the molten metal magnesium in the molten state cannot be obtained during the reaction. It is well infiltrated with these molten salts, resulting in insufficient contact reaction between magnesium and the reactants, thus requiring a longer reaction time and more magnesium, and the purity of the product is not high.
然而，尽管纳米硅可以解决体积膨胀问题，但是大部分纳米硅的多孔主要是由很多纳米硅颗粒堆积而成，纳米硅并没有形成一个整体，当体积膨胀时会导致颗粒间的分离失去良好的电接触，最终导致电子无法有效的传输，容量减弱会加速，倍率性能较差，都需要复杂的碳包裹纳米硅来解决这个问题，增加成本跟工序，无法广泛推广。另外，相对于多孔微米颗粒，由于纳米颗粒表面活化能很高导致电极材料振实密度低，从而使得单 位体积的电极材料能量较低，因此导致电池体积过大，影响广泛使用。However, although nano-silicon can solve the problem of volume expansion, most of the nano-silicon porous is mainly composed of many nano-silicon particles. Nano-silicon does not form a whole. When the volume expands, the separation between particles will lose good. Electrical contact eventually leads to inefficient transmission of electrons, accelerated capacity reduction, and poor rate performance. Both require complex carbon-coated nano-silicon to solve this problem, increase cost and process, and cannot be widely promoted. In addition, compared with the porous microparticles, the high surface activation energy of the nanoparticles leads to low tap density of the electrode material, so that the energy of the electrode material of the unit volume is low, thereby causing the battery to be too bulky and affecting widespread use.
[发明内容][Summary of the Invention]
针对现有技术的以上缺陷或改进需求，本发明提供了一种三维多孔硅及其制备方法和应用，其目的在于通过以硅酸盐玻璃为原料，以镁的卤化物为熔盐，采用低温镁热还原反应制备得到纳米多孔硅，由此解决现有技术纳米硅制备方法条件苛刻、成本昂贵、步骤复杂、污染严重，同时制备得到的纳米硅团聚现象严重、副产物多、多孔结构仅存在于硅颗粒之间以及体积能量密度低不能满足电池负极材料的应用要求等技术问题。In view of the above defects or improvement requirements of the prior art, the present invention provides a three-dimensional porous silicon and a preparation method and application thereof, the object of which is to use a silicate glass as a raw material, a magnesium halide as a molten salt, and a low temperature. The nanoporous silicon is prepared by the magnesium thermal reduction reaction, thereby solving the prior art nano silicon preparation method, the conditions are harsh, the cost is high, the steps are complicated, and the pollution is serious. At the same time, the prepared nano silicon agglomeration phenomenon is serious, the by-products are many, and the porous structure exists only. The technical problems such as the application requirements of the negative electrode material of the battery cannot be satisfied between the silicon particles and the low volume energy density.
为实现上述目的，按照本发明的一个方面，提供了一种多孔硅颗粒，所述多孔硅颗粒的粒径范围为1～5微米，所述多孔硅颗粒内部具有三维贯通的孔结构，所述孔结构中大孔结构尺寸为50～200纳米，介孔结构的尺寸为2～6纳米。In order to achieve the above object, according to an aspect of the invention, there is provided a porous silicon particle having a particle diameter ranging from 1 to 5 μm, the porous silicon particle having a three-dimensionally penetrating pore structure therein, The size of the macroporous structure in the pore structure is 50 to 200 nm, and the size of the mesoporous structure is 2 to 6 nm.
优选地，所述多孔硅颗粒的比表面积为270～380m 2g -1。 Preferably, the porous silicon particles have a specific surface area of 270 to 380 m 2 g -1 .
优选地，所述多孔硅颗粒的振实密度为0.76～0.835g/cm 3。 Preferably, the porous silicon particles have a tap density of 0.76 to 0.835 g/cm 3 .
按照本发明的另一个方面，提供了一种三维多孔微米硅的制备方法，将粉末状硅酸盐基玻璃、镁粉与熔盐按照质量比1：(0.5～0.8)：(5～8)混合均匀后，以1～10℃/min的升温速度加热到605～750℃保温1～12h，然后酸洗得到多孔微米硅。According to another aspect of the present invention, there is provided a method for preparing a three-dimensional porous micron silicon, wherein the powdered silicate-based glass, the magnesium powder and the molten salt are in a mass ratio of 1: (0.5 to 0.8): (5 to 8) After mixing uniformly, the mixture is heated at 605 to 750 ° C for 1 to 12 hours at a temperature increase rate of 1 to 10 ° C / min, and then pickled to obtain porous micro silicon.
优选地，所述硅酸盐玻璃为硅酸钠玻璃或硅酸钙玻璃。Preferably, the silicate glass is sodium silicate glass or calcium silicate glass.
优选地，所述熔盐为卤化镁。Preferably, the molten salt is a magnesium halide.
优选地，所述熔盐为氯化镁、溴化镁或碘化镁。Preferably, the molten salt is magnesium chloride, magnesium bromide or magnesium iodide.
优选地，所述熔盐为氯化镁。Preferably, the molten salt is magnesium chloride.
优选地，所述的制备方法，包括如下步骤：Preferably, the preparation method comprises the following steps:
(1)将硅酸盐玻璃清洗后机械球磨成玻璃粉末，得到粉末状的硅酸盐玻璃；(1) mechanically ball-milling the silicate glass into a glass powder to obtain a powdered silicate glass;
(2)将步骤(1)得到的粉末状的硅酸盐玻璃、镁粉与卤化镁按照质 量比为1：(0.5～0.8)：(5～8)混合均匀得到混合物；(2) mixing the powdery silicate glass, magnesium powder and magnesium halide obtained in the step (1) in a mass ratio of 1: (0.5 to 0.8): (5 to 8) to obtain a mixture;
(3)将步骤(2)得到的混合物以1～10℃/min的升温速度加热到605～750℃保温1～12h，得到反应后的混合物；(3) The mixture obtained in the step (2) is heated at a temperature increase rate of 1 to 10 ° C / min to 605 to 750 ° C for 1 to 12 hours to obtain a mixture after the reaction;
(4)将步骤(3)得到的反应后的混合物进行酸洗，酸洗后得到多孔硅颗粒。(4) The mixture obtained after the reaction obtained in the step (3) is subjected to pickling, and after pickling, porous silicon particles are obtained.
优选地，所述酸洗步骤具体为：在1mol/L的盐酸中搅拌条件下清洗1～8h，然后在0.1mol/L的氢氟酸中清洗，干燥得到多孔微米硅颗粒。Preferably, the pickling step is specifically: washing in 1 mol/L hydrochloric acid under stirring for 1-8 h, then washing in 0.1 mol/L hydrofluoric acid, and drying to obtain porous micron silicon particles.
按照本发明的另一个方面，提供了一种所述的多孔硅颗粒的应用，应用于锂离子电池负极材料。According to another aspect of the present invention, there is provided the use of the porous silicon particles described above for use in a lithium ion battery negative electrode material.
总体而言，通过本发明所构思的以上技术方案与现有技术相比，能够取得下列有益效果。In general, the above technical solutions conceived by the present invention can achieve the following advantageous effects as compared with the prior art.
(1)本发明制备多孔硅采用的原料为硅酸盐玻璃，原料来源广泛，合成方法简单易行，成本低廉，产率纯度高，可大规模生产，原料也可回收循环使用；(1) The raw material used for preparing porous silicon of the invention is silicate glass, the raw material source is wide, the synthesis method is simple and easy, the cost is low, the yield purity is high, the large-scale production can be carried out, and the raw materials can also be recycled and recycled;
(2)原料硅酸盐玻璃在605℃～750℃处于熔融态，此温度也处于反应温度范围内且镁粉也处于液态，是一种“液-液”镁热反应优于其他“固-液”镁热反应，便于反应充分进行并得到稳定的、分布均匀的三维多孔结构；(2) The raw material silicate glass is in a molten state at 605 ° C ~ 750 ° C, this temperature is also in the reaction temperature range and the magnesium powder is also in a liquid state, which is a "liquid-liquid" magnesium thermal reaction superior to other "solid" The liquid "magnesium thermal reaction" facilitates the reaction to proceed sufficiently and obtains a stable, uniformly distributed three-dimensional porous structure;
(3)在制备过程中用氯化镁，溴化镁，碘化镁等镁的金属盐作为熔盐，由于这些熔盐的熔点也在605-750℃之间，一方面保证反应环境稳定，并作为吸热剂避免产物团聚烧结，另一方面由于这些镁盐熔融态下对镁粉有更好的溶解性以及对反应物有更加好的润湿性，使得整个反应更宜进行，反应更充分，反应所需能量更低，整个反应更加安全；(3) In the preparation process, a metal salt of magnesium such as magnesium chloride, magnesium bromide or magnesium iodide is used as a molten salt. Since the melting point of these molten salts is also between 605 and 750 ° C, on the one hand, the reaction environment is stabilized and The heat absorbing agent avoids agglomeration and sintering of the product, and on the other hand, because the magnesium salt has better solubility to the magnesium powder in the molten state and better wettability to the reactant, the whole reaction is more suitable and the reaction is more complete. The energy required for the reaction is lower and the overall reaction is safer;
(4)本发明所制备出的三维多孔硅具有锂离子电池负极材料应有的优点：多孔结构既可以有利电解液接触又可以缓解嵌锂过程中的体积膨胀，三维多孔结构还有利于电极材料反应是向内膨胀进而保证这个电极膜的厚度保持稳定，大大提高目前锂离子电池的安全性；此外，这种三维贯穿结 构更有利于锂离子传输，应用前景广泛。(4) The three-dimensional porous silicon prepared by the invention has the advantages of the negative electrode material of the lithium ion battery: the porous structure can not only facilitate the contact of the electrolyte but also alleviate the volume expansion during the process of intercalating lithium, and the three-dimensional porous structure is also beneficial to the electrode material. The reaction is inwardly expanded to ensure that the thickness of the electrode film is kept stable, and the safety of the current lithium ion battery is greatly improved; in addition, the three-dimensional through structure is more advantageous for lithium ion transmission, and has wide application prospects.
(5)微米级别的尺寸具有大的振实密度可以达到提高电极单位体积能量密度，本发明制备的多孔微米硅的振实密度为0.81g/cm 3，而市购纳米硅的振实密度仅为0.15g/cm 3。 (5) The micron-scale size has a large tap density to increase the energy density per unit volume of the electrode. The tap density of the porous micro-silica prepared by the present invention is 0.81 g/cm 3 , and the tap density of commercially available nano-silicon is only It is 0.15 g/cm 3 .
(6)本发明多孔微米硅的制备方法各步骤协同合作，构成了一套独立的技术方案，制备得到了优良的多孔微米硅。本发明选择硅酸盐基玻璃为原料，以卤化镁为熔盐，由于二者在605-750℃之间均为熔融态，这样才能够实现熔融态反应，实现了良好的传质，而硅酸盐基玻璃本身由于含有钠、钙、镁、铝等杂质共生其中以及互熔的熔盐骨架贯穿其中，利用这一独特的优势，通过酸洗反应产物，得到了三维贯通的微米硅的多孔结构。(6) The steps of the preparation method of the porous micron silicon of the present invention cooperate to form an independent technical scheme, and the excellent porous micro silicon is prepared. The invention selects the silicate-based glass as the raw material and the magnesium halide as the molten salt. Since the two are in a molten state between 605 and 750 ° C, the molten state reaction can be realized, and good mass transfer is achieved, and silicon is obtained. The acid-based glass itself contains symbiotic impurities such as sodium, calcium, magnesium and aluminum, and the molten-melting molten salt skeleton penetrates through it. With this unique advantage, the porous reaction micro-silicon is obtained by pickling the reaction product. structure.
[附图说明][Description of the Drawings]
图1为本发明实施例1制备得到的三维多孔硅的扫描电镜图；1 is a scanning electron micrograph of three-dimensional porous silicon prepared in Example 1 of the present invention;
图2为本发明实施例1制备得到的三维多孔硅的XRD图谱；2 is an XRD pattern of the three-dimensional porous silicon prepared in Example 1 of the present invention;
图3为本发明实施例1制备得到的三维多孔硅的透射电镜图；3 is a transmission electron micrograph of the three-dimensional porous silicon prepared in Example 1 of the present invention;
图4为本发明实施例1制备得到的三维多孔硅的电化学循环性能图；4 is a graph showing electrochemical cycle performance of three-dimensional porous silicon prepared in Example 1 of the present invention;
图5为本发明实施例1制备得到的三维多孔硅的吸附和解吸附曲线以及孔径分布曲线。5 is a graph showing adsorption and desorption curves and pore size distribution curves of three-dimensional porous silicon prepared in Example 1 of the present invention.
[具体实施方式][detailed description]
为了使本发明的目的、技术方案及优点更加清楚明白，以下结合附图及实施例，对本发明进行进一步详细说明。应当理解，此处所描述的具体实施例仅仅用以解释本发明，并不用于限定本发明。此外，下面所描述的本发明各个实施方式中所涉及到的技术特征只要彼此之间未构成冲突就可以相互组合。The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. Further, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not constitute a conflict with each other.
本发明提供的多孔硅颗粒的粒径范围为1～5微米，所述多孔微米硅颗粒内部具有三维贯通的孔结构，所述孔结构中大孔结构尺寸为50～200纳米，介孔结构的尺寸为2～6纳米。所述多孔硅颗粒的比表面积为270～380m 2 g -1。所述多孔硅颗粒的振实密度为0.76～0.835g/cm 3。 The porous silicon particles provided by the present invention have a particle size ranging from 1 to 5 micrometers, and the porous micron silicon particles have a three-dimensionally penetrating pore structure therein, and the macroporous structure size of the pore structure is 50 to 200 nm, and the mesoporous structure The size is 2 to 6 nm. The porous silicon particles have a specific surface area of 270 to 380 m 2 g -1 . The porous silicon particles have a tap density of 0.76 to 0.835 g/cm 3 .
该三维多孔微米硅的制备方法为：将粉末状硅酸盐基玻璃、镁粉与熔盐按照质量比1：(0.5～0.8)：(5～8)混合均匀后，以1～10℃/min的升温速度加热到605～750℃保温1～12h，然后酸洗得到多孔微米硅。The method for preparing the three-dimensional porous micron silicon is: mixing the powdered silicate-based glass, the magnesium powder and the molten salt according to a mass ratio of 1: (0.5-0.8): (5-8), and then 1 to 10 ° C / The heating rate of min is heated to 605-750 ° C for 1-12 h, and then pickled to obtain porous micron silicon.
所述硅酸盐玻璃为硅酸钠玻璃或硅酸钙玻璃。所述熔盐为卤化镁，包括氯化镁、溴化镁或碘化镁，优选为氯化镁。The silicate glass is sodium silicate glass or calcium silicate glass. The molten salt is a magnesium halide, including magnesium chloride, magnesium bromide or magnesium iodide, preferably magnesium chloride.
具体地，该制备方法，包括如下步骤：Specifically, the preparation method includes the following steps:
(1)将硅酸盐玻璃清洗后机械球磨成玻璃粉末，得到粉末状的硅酸盐玻璃；(1) mechanically ball-milling the silicate glass into a glass powder to obtain a powdered silicate glass;
(2)将步骤(1)得到的粉末状的硅酸盐玻璃、镁粉与卤化镁按照质量比为1：(0.5～0.8)：(5～8)混合均匀得到混合物；(2) mixing the powdery silicate glass, the magnesium powder obtained in the step (1) and the magnesium halide in a mass ratio of 1: (0.5 to 0.8): (5 to 8) to obtain a mixture;
(3)将步骤(2)得到的混合物以1～10℃/min的升温速度加热到605～750℃保温1～12h，得到反应后的混合物；(3) The mixture obtained in the step (2) is heated at a temperature increase rate of 1 to 10 ° C / min to 605 to 750 ° C for 1 to 12 hours to obtain a mixture after the reaction;
(4)将步骤(3)得到的反应后的混合物进行酸洗，酸洗后得到多孔硅颗粒。(4) The mixture obtained after the reaction obtained in the step (3) is subjected to pickling, and after pickling, porous silicon particles are obtained.
作为优选的方案，将硅酸盐玻璃粉末、镁粉、熔盐(MgCl 2)按照质量比为1：0.6：6的量球磨混合均匀；然后将混合物放入管式炉中以5℃/min的升温速度加热到650℃保温3h，待产物随炉冷却至室温后取出；镁粉与煤焦油量的选择保证反应完全得到纳米碳化硅减少副产物，MgCl 2的量选择既可保证反应有足够的熔融介质又可以通过反应焓变计算得到恰当的吸热效果防止颗粒烧结团聚。升温速度优选5℃/min，既可以保证反应时间短又可以保证产物的多孔结构更稳定。反应温度优选650℃，一方面接近镁粉熔点(649℃)保证镁粉熔融态反应，反应接触更充分，另一方面此温度下硅酸盐玻璃也处于熔融态，更有利于多孔结构的保持。 As a preferred embodiment, the silicate glass powder, the magnesium powder, the molten salt (MgCl 2 ) are ball milled uniformly in a mass ratio of 1:0.6:6; then the mixture is placed in a tube furnace at 5 ° C/min. The heating rate is heated to 650 ° C for 3 h, and the product is taken out after cooling to room temperature with the furnace; the selection of magnesium powder and coal tar ensures that the reaction completely obtains nano-silicon carbide to reduce by-products, and the amount of MgCl 2 can ensure sufficient reaction. The molten medium can be calculated by reaction enthalpy to obtain an appropriate endothermic effect to prevent particle sintering agglomeration. The heating rate is preferably 5 ° C / min, which not only ensures a short reaction time but also ensures a more stable porous structure of the product. The reaction temperature is preferably 650 ° C. On the one hand, close to the melting point of magnesium powder (649 ° C) to ensure the molten state of the magnesium powder reaction, the reaction contact is more sufficient, on the other hand, the silicate glass is also in a molten state at this temperature, which is more favorable for the maintenance of the porous structure. .
所述酸洗步骤具体为：在1mol/L的盐酸中清洗并搅拌1～8h然后在0.1mol/L的氢氟酸中清洗10min～30min，干燥得到多孔硅纳米颗粒。The pickling step is specifically: washing and stirring in 1 mol/L hydrochloric acid for 1-8 h and then washing in 0.1 mol/L hydrofluoric acid for 10 min to 30 min, and drying to obtain porous silicon nanoparticles.
酸洗是形成多孔结构的关键，熔融反应后硅酸盐基玻璃中的钠钙镁铝的氧化物、产物氧化镁以及熔盐骨架残留在产物硅中，酸洗溶解掉硅颗粒内部的钠钙镁铝的氧化物、产物氧化镁以及熔盐，液液反应由于钠钙镁铝的氧化物、产物氧化镁以及熔盐在硅酸盐基玻璃中是三维贯通存在于其中，因此经过“液-液”反应并酸洗之后，可得到硅颗粒内部的三维贯通的孔结构。Pickling is the key to the formation of a porous structure. The sodium, calcium, magnesium and aluminum oxides, the product magnesium oxide and the molten salt skeleton in the silicate-based glass remain in the product silicon after the melting reaction, and the sodium calcium in the silicon particles is dissolved by pickling. Magnesium-aluminum oxide, product magnesium oxide and molten salt, liquid-liquid reaction, since the sodium calcium-magnesium-aluminum oxide, the product magnesium oxide and the molten salt are three-dimensionally penetrated in the silicate-based glass, After the liquid is reacted and pickled, a three-dimensionally penetrating pore structure inside the silicon particles can be obtained.
本发明制备得到的多孔硅颗粒可以应用于锂离子电池负极材料。The porous silicon particles prepared by the invention can be applied to a lithium ion battery anode material.
本发明提供的一种以硅酸盐基玻璃为原料制备三维多孔硅的方法，包括以下步骤：将玻璃碾磨碎，然后通过机械球磨的方法将玻璃的颗粒尺寸降低后将玻璃粉末和镁粉、熔盐按照一定的比例均匀球磨混合后放入在惰性气体下反应，反应式为M xSiO 3+2Mg＝2MgO+Si+M xO，其中M为Na，Ca，Mg和Al中的一种或多种，随后将反应产物酸洗处理得到三维多孔硅。 The invention provides a method for preparing three-dimensional porous silicon by using silicate-based glass as a raw material, comprising the steps of: grinding glass, and then reducing the particle size of the glass by mechanical ball milling to remove the glass powder and the magnesium powder. The molten salt is uniformly ball milled and mixed according to a certain ratio, and then reacted under an inert gas, and the reaction formula is M x SiO 3 + 2Mg=2MgO+Si+M x O, wherein M is one of Na, Ca, Mg and Al. One or more kinds, and then the reaction product is pickled to obtain three-dimensional porous silicon.
本发明选用熔点在反应温度附近的硅酸盐玻璃为原料，这既可以保证反应充分进行又可以产生结构稳定的三维多孔结构。普通的硅酸盐基玻璃在605～750℃处于熔化状态的特征，反应时镁粉也是熔融态，保证一种优异的“液-液”反应发生，有利于原料与液态Mg的充分接触和快速传质过程，液液反应相对于固液或固固反应，体系温度和成分更均匀，多孔结构更稳定，普通玻璃反应后存在的碱性氧化物Na 2O，CaO，反应产物MgO以及熔盐等骨架结构会以三维贯通的形式残留在产物硅的颗粒中，通过酸洗后去掉骨架结构能得到硅颗粒内部的具有三维贯通的孔结构的多孔微米硅。 In the invention, the silicate glass having a melting point near the reaction temperature is selected as the raw material, which can ensure the sufficient reaction and the three-dimensional porous structure with stable structure. Ordinary silicate-based glass is characterized by being in a molten state at 605-750 ° C. The magnesium powder is also in a molten state during the reaction, ensuring an excellent "liquid-liquid" reaction, which is beneficial to the sufficient contact and rapid contact of the raw material with the liquid Mg. Mass transfer process, liquid-liquid reaction relative to solid-liquid or solid-solid reaction, system temperature and composition are more uniform, porous structure is more stable, basic oxide Na 2 O, CaO, reaction product MgO and molten salt existing after ordinary glass reaction The skeleton structure remains in the form of three-dimensional through-grain in the particles of the product silicon, and the porous micro-silicon having a three-dimensional through-hole structure inside the silicon particles can be obtained by removing the skeleton structure after pickling.
本发明采用氯化镁(MgCl 2)、溴化镁(MgBr 2)和碘化镁(MgI 2)等作为熔盐通过熔化吸热将反应温度控制在800℃以下，使整个反应在相对温和的条件下充分进行，使反应所需要的能量更低并能解决纳米颗粒团聚烧结。在熔盐的选择上有别于上述传统的熔盐体系(NaCl、KCl体系)是一种创新的熔盐体系方案。 The invention adopts magnesium chloride (MgCl 2 ), magnesium bromide (MgBr 2 ) and magnesium iodide (MgI 2 ) as the molten salt to control the reaction temperature below 800 ° C by melting endotherm, so that the whole reaction is under relatively mild conditions. Properly carried out, the energy required for the reaction is lower and the agglomeration sintering of the nanoparticles can be solved. The choice of molten salt is different from the above traditional molten salt system (NaCl, KCl system) is an innovative molten salt system.
本发明中用到的工业和生活中废弃的硅酸盐基玻璃相对于其他含硅矿 物质来说来源丰富且简单易得，利用现有的废物，采用低温镁热还原反应得到纳米硅使其有了更大的利用价值，制备的三维多孔硅具有纯度较高、比表面积大、颗粒均匀且存在介孔等特点，可以应用于锂离子电池负极材料领域。The industrial and domestic waste silicate-based glass used in the present invention is rich in source and simple to obtain relative to other silicon-containing minerals, and uses the existing waste to obtain nano-silicon by low-temperature magnesia reduction reaction. With greater utilization value, the prepared three-dimensional porous silicon has the characteristics of high purity, large specific surface area, uniform particles and mesopores, and can be applied to the field of anode materials for lithium ion batteries.
以下为实施例：The following are examples:
实施例1Example 1
(1)将5g硅酸钠玻璃先简单的用去离子水反复清洗后干燥；将清洗后的普通玻璃研磨成粉末，进一步通过机械球磨的方法将其加工到微米级；(1) 5 g of sodium silicate glass is simply washed repeatedly with deionized water and dried; the cleaned ordinary glass is ground into a powder, and further processed to a micron level by mechanical ball milling;
(2)将球磨好的硅酸盐玻璃粉末、镁粉、熔盐(MgCl 2)按照质量比为1：0.6：8的量球磨混合均匀； (2) ball-milled silicate glass powder, magnesium powder, molten salt (MgCl 2 ) in a mass ratio of 1:0.6:8 by ball milling and mixing;
(3)然后将混合物放入管式炉中以5℃/min的升温速度加热到650℃保温3h，待产物随炉冷却至室温后取出；(3) Then, the mixture is placed in a tube furnace and heated at 650 ° C for 3 h at a heating rate of 5 ° C / min, and the product is taken out after being cooled to room temperature with the furnace;
(4)将所得产物先在1mol/L盐酸中清洗1小时。然后在0.1mol/L的氢氟酸中清洗0.5小时，抽滤后干燥得到多孔硅颗粒。(4) The obtained product was first washed in 1 mol/L hydrochloric acid for 1 hour. Then, it was washed in 0.1 mol/L of hydrofluoric acid for 0.5 hour, filtered by suction, and dried to obtain porous silicon particles.
由图1的扫描电镜图可知，本实施例制备得到的硅属于1～5微米级别的三维多孔结构的硅，放大图可以看见在硅颗粒内部具有明显的三维贯通的多孔结构。It can be seen from the scanning electron micrograph of FIG. 1 that the silicon prepared in this embodiment belongs to a three-dimensional porous structure of silicon of the order of 1 to 5 micrometers, and an enlarged view shows a porous structure having a distinct three-dimensional penetration inside the silicon particles.
由图2的XRD衍射图谱可知，在28.4°、47.3°和56.1°的三强峰与硅(JCPDS No.27-1402)的三强峰相对应，并基本无杂相。It can be seen from the XRD diffraction pattern of Fig. 2 that the three strong peaks at 28.4°, 47.3°, and 56.1° correspond to the three strong peaks of silicon (JCPDS No. 27-1402), and are substantially free of impurities.
由图3的透射电镜图可知，本实施例制备得到的三维多孔硅，具有优异的孔道结构且整体结构没有破坏，且其中大孔孔径为50～200纳米。It can be seen from the transmission electron micrograph of FIG. 3 that the three-dimensional porous silicon prepared in this embodiment has an excellent pore structure and no damage to the overall structure, and the macropore pore diameter is 50 to 200 nm.
图4所示多孔硅优异的电化学循环性能，循环100次仍有较高的容量，循环稳定性好，因此本发明可在工业上大规模生产和应用。The porous silicon shown in Fig. 4 has excellent electrochemical cycle performance, has a high capacity after 100 cycles, and has good cycle stability, so that the present invention can be industrially produced and applied on a large scale.
如图5所示，多孔硅的比表面积为380m 2g -1，其中介孔孔径为2～6纳米。经测试该多孔微米硅的振实密度为0.81g/cm 3，此方法合成的多孔硅具有超高的比表面积和优异的孔结构，适合用于锂电池负极材料。 As shown in FIG. 5, the porous silicon has a specific surface area of 380 m 2 g -1 and a mesoporous pore diameter of 2 to 6 nm. The tested micron porous silicon tap density of 0.81g / cm 3, this method of synthesizing the porous silicon having a super high specific surface area and excellent pore structure, suitable for a negative electrode material for a lithium battery.
实施例2Example 2
将5g硅酸钙玻璃先简单的用去离子水反复清洗后干燥；将清洗后的废弃玻璃研磨成粉末，进一步通过机械球磨的方法将其加工到微米级；5g of calcium silicate glass is simply washed repeatedly with deionized water and dried; the cleaned waste glass is ground into a powder, and further processed to a micron level by mechanical ball milling;
(2)将球磨好的硅酸盐玻璃粉末、镁粉、熔盐(MgCl 2)按照质量比为1：0.8：7的量球磨混合均匀； (2) ball-milled silicate glass powder, magnesium powder, molten salt (MgCl 2 ) in a mass ratio of 1:0.8:7 by ball milling and mixing;
(3)然后将混合物放入管式炉中以1℃/min的升温速度加热到605℃保温12h，待产物随炉冷却至室温后取出；(3) The mixture is then placed in a tube furnace and heated at 605 ° C for 12 h at a heating rate of 1 ° C / min, and the product is taken out after cooling to room temperature with the furnace;
(4)将所得产物分别在1mol/L的盐酸中清洗并搅拌2h然后在0.1mol/L的氢氟酸中清洗0.5小时，反复清洗抽滤后干燥得到多孔硅颗粒。(4) The obtained product was washed with 1 mol/L hydrochloric acid, respectively, and stirred for 2 hours, and then washed in 0.1 mol/L of hydrofluoric acid for 0.5 hour, repeatedly washed, suction-filtered, and dried to obtain porous silicon particles.
实施例3Example 3
将5g硅酸钠玻璃先简单的用去离子水反复清洗后干燥；将清洗后的废弃玻璃研磨成粉末，进一步通过机械球磨的方法将其加工到微米级；5 g of sodium silicate glass is simply washed repeatedly with deionized water and dried; the cleaned waste glass is ground into a powder, and further processed to a micron level by mechanical ball milling;
(2)将球磨好的硅酸盐玻璃粉末、镁粉、熔盐(MgBr 2)按照质量比为1：0.5：7的量球磨混合均匀； (2) ball-milled silicate glass powder, magnesium powder, molten salt (MgBr 2 ) in a mass ratio of 1:0.5:7 by ball milling and mixing;
(3)然后将混合物放入管式炉中以2℃/min的升温速度加热到605℃保温12h，待产物随炉冷却至室温后取出；(3) The mixture is then placed in a tube furnace and heated to 605 ° C for 12 h at a temperature increase rate of 2 ° C / min, and the product is taken out after cooling to room temperature with the furnace;
(4)将所得产物分别在1mol/L的硝酸中清洗并搅拌然后在0.1mol/L的氢氟酸中清洗0.5小时，反复清洗抽滤后干燥得到多孔硅颗粒。(4) The obtained product was washed with 1 mol/L of nitric acid and stirred, and then washed in 0.1 mol/L of hydrofluoric acid for 0.5 hour, repeatedly washed, suction-filtered, and dried to obtain porous silicon particles.
实施例4Example 4
(1)将5g硅酸钙玻璃先简单的用去离子水反复清洗后干燥；将清洗后的废弃玻璃研磨成粉末，进一步通过机械球磨的方法将其加工到微米级；(1) 5 g of calcium silicate glass is simply washed repeatedly with deionized water and dried; the cleaned waste glass is ground into a powder, and further processed to a micron level by mechanical ball milling;
(2)将球磨好的硅酸盐玻璃粉末、镁粉、熔盐(MgI 2)按照质量比为1：0.7：6的量球磨混合均匀； (2) ball-milled silicate glass powder, magnesium powder, molten salt (MgI 2 ) in a mass ratio of 1:0.7:6 by ball milling and mixing;
(3)然后将混合物放入管式炉中以3℃/min的升温速度加热到700℃保温3h，待产物随炉冷却至室温后取出；(3) The mixture is then placed in a tube furnace and heated at 700 ° C for 3 h at a temperature increase rate of 3 ° C / min, and the product is taken out after cooling to room temperature with the furnace;
(4)将所得产物分别在1mol/L的盐酸中清洗并搅拌4h然后在0.1mol/L 的氢氟酸中清洗0.5小时，反复清洗抽滤后干燥得到多孔硅颗粒。(4) The obtained product was washed with 1 mol/L hydrochloric acid, respectively, and stirred for 4 hours, and then washed in 0.1 mol/L of hydrofluoric acid for 0.5 hour, repeatedly washed, suction-filtered, and dried to obtain porous silicon particles.
实施例5Example 5
(1)将5g硅酸钙玻璃先简单的用去离子水反复清洗后干燥；将清洗后的废弃玻璃(1) 5g of calcium silicate glass is simply washed repeatedly with deionized water and dried; the discarded glass after cleaning
研磨成粉末，进一步通过机械球磨的方法将其加工到微米级；Grinding into a powder and further processing it to a micron level by mechanical ball milling;
(2)将球磨好的硅酸盐玻璃粉末、镁粉、熔盐(MgCl 2)按照质量比为1：0.65：5的量球磨混合均匀； (2) ball-milled silicate glass powder, magnesium powder, molten salt (MgCl 2 ) in a mass ratio of 1:0.65:5 by ball milling and mixing;
(3)然后将混合物放入管式炉中以10℃/min的升温速度加热到750℃保温3h，待产物随炉冷却至室温后取出；(3) The mixture is then placed in a tube furnace and heated at 750 ° C for 3 h at a heating rate of 10 ° C / min, and the product is taken out after cooling to room temperature with the furnace;
(4)将所得产物分别在1mol/L的盐酸中清洗并搅拌1h然后在0.1mol/L氟酸中清洗0.5小时，反复清洗抽滤后干燥得到多孔硅颗粒。(4) The obtained product was washed with 1 mol/L hydrochloric acid, respectively, and stirred for 1 hour, and then washed in 0.1 mol/L of hydrofluoric acid for 0.5 hour, repeatedly washed and suction-filtered, and dried to obtain porous silicon particles.
本领域的技术人员容易理解，以上所述仅为本发明的较佳实施例而已，并不用以限制本发明，凡在本发明的精神和原则之内所作的任何修改、等同替换和改进等，均应包含在本发明的保护范围之内。Those skilled in the art will appreciate that the above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and scope of the present invention, All should be included in the scope of protection of the present invention.

Claims (10)

  1. 一种多孔硅颗粒，其特征在于，所述多孔硅颗粒的粒径范围为1～5微米，所述多孔硅颗粒内部具有三维贯通的孔结构，所述孔结构中大孔结构尺寸为50～200纳米，介孔结构的尺寸为2～6纳米。A porous silicon particle characterized in that the porous silicon particles have a particle diameter ranging from 1 to 5 μm, and the porous silicon particles have a three-dimensionally penetrating pore structure therein, and the pore structure size of the pore structure is 50 ～ At 200 nm, the mesoporous structure has a size of 2 to 6 nm.
  2. 如权利要求1所述的多孔硅颗粒，其特征在于，所述多孔硅颗粒的比表面积为270～380m 2g -1。 The porous silicon particle according to claim 1, wherein the porous silicon particles have a specific surface area of from 270 to 380 m 2 g -1 .
  3. 如权利要求1所述的多孔硅颗粒，其特征在于，所述多孔硅颗粒的振实密度为0.76～0.835g/cm 3。 The porous silicon particle according to claim 1, wherein the porous silicon particles have a tap density of 0.76 to 0.835 g/cm 3 .
  4. 一种三维多孔微米硅的制备方法，其特征在于，将粉末状硅酸盐基玻璃、镁粉与熔盐按照质量比1：(0.5～0.8)：(5～8)混合均匀后，以1～10℃/min的升温速度加热到605～750℃保温1～12h，然后酸洗得到多孔微米硅。A method for preparing three-dimensional porous micron silicon, characterized in that powdered silicate-based glass, magnesium powder and molten salt are uniformly mixed according to a mass ratio of 1: (0.5 to 0.8): (5 to 8), and then The temperature rise rate of ～10 ° C / min is heated to 605 ~ 750 ° C for 1 ~ 12h, and then pickled to obtain porous micron silicon.
  5. 如权利要求4所述的制备方法，其特征在于，所述硅酸盐玻璃为硅酸钠玻璃或硅酸钙玻璃。The method according to claim 4, wherein the silicate glass is sodium silicate glass or calcium silicate glass.
  6. 如权利要求4所述的制备方法，其特征在于，所述熔盐为卤化镁。The method according to claim 4, wherein the molten salt is a magnesium halide.
  7. 如权利要求4所述的制备方法，其特征在于，所述熔盐为氯化镁、溴化镁或碘化镁，优选为氯化镁。The process according to claim 4, wherein the molten salt is magnesium chloride, magnesium bromide or magnesium iodide, preferably magnesium chloride.
  8. 如权利要求4所述的制备方法，其特征在于，包括如下步骤：The preparation method according to claim 4, comprising the steps of:
    (1)将硅酸盐玻璃清洗后机械球磨成玻璃粉末，得到粉末状的硅酸盐玻璃；(1) mechanically ball-milling the silicate glass into a glass powder to obtain a powdered silicate glass;
    (2)将步骤(1)得到的粉末状的硅酸盐玻璃、镁粉与卤化镁按照质量比为1：(0.5～0.8)：(5～8)混合均匀得到混合物；(2) mixing the powdery silicate glass, the magnesium powder obtained in the step (1) and the magnesium halide in a mass ratio of 1: (0.5 to 0.8): (5 to 8) to obtain a mixture;
    (3)将步骤(2)得到的混合物以1～10℃/min的升温速度加热到605～750℃保温1～12h，得到反应后的混合物；(3) The mixture obtained in the step (2) is heated at a temperature increase rate of 1 to 10 ° C / min to 605 to 750 ° C for 1 to 12 hours to obtain a mixture after the reaction;
    (4)将步骤(3)得到的反应后的混合物进行酸洗，酸洗后得到多孔硅颗粒。(4) The mixture obtained after the reaction obtained in the step (3) is subjected to pickling, and after pickling, porous silicon particles are obtained.
  9. 如权利要求8所述的制备方法，其特征在于，所述酸洗步骤具体为：在1mol/L的盐酸中，搅拌条件下清洗1～8h，然后在0.1mol/L的氢氟酸中清洗，干燥得到多孔微米硅颗粒。The preparation method according to claim 8, wherein the pickling step is specifically: washing in 1 mol/L hydrochloric acid under stirring for 1 to 8 hours, and then washing in 0.1 mol/L of hydrofluoric acid. Dry to obtain porous micron silicon particles.
  10. 一种如权利要求1～3任意一项所述的多孔硅颗粒的应用，其特征在于，应用于锂离子电池负极材料。Use of the porous silicon particles according to any one of claims 1 to 3, which is applied to a lithium ion battery negative electrode material.
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