CN115241426A - Micron silicon-carbon composite material for lithium ion battery cathode and preparation method thereof - Google Patents

Abstract

The invention belongs to the field of lithium ion battery materials, and discloses a micron silicon-carbon composite lithium ion battery cathode material and a preparation method thereof. The preparation method comprises the following steps: carrying out ball milling on micron silicon and conductive carbon to obtain a precursor A; adding a carbon source precursor into a solvent to obtain a carbon source solution B; (2) Adding the precursor A into a carbon source solution B, and alternately stirring and ultrasonically treating to obtain uniformly mixed slurry C; (3) Adding the slurry C into an aqueous solution of a surfactant for shaping under stirring, filtering and drying to obtain a precursor D; (4) And placing the precursor D in a protective atmosphere for high-temperature carbonization to obtain the micron silicon-carbon composite material. The method takes micron-sized silicon-based materials as raw materials, and adopts a ball milling and surfactant assisted method to form a core-shell structure; the material has a stable structure, and the external carbon shell can effectively relieve the volume change of silicon and keep the electrode structure stable. The invention has low cost and simple preparation method, and is beneficial to large-scale production.

Description

Translated fromChinese

一种用于锂离子电池负极的微米硅碳复合材料及制备方法A kind of micron silicon carbon composite material for negative electrode of lithium ion battery and preparation method thereof

技术领域technical field

本发明属于锂离子电池材料领域，具体涉及一种用于锂离子电池负极的微米硅碳复合材料及制备方法。The invention belongs to the field of lithium ion battery materials, and in particular relates to a micron silicon-carbon composite material for a negative electrode of a lithium ion battery and a preparation method.

背景技术Background technique

近些年来，便携式电子产品、电动汽车等各种应用领域的发展对高性能锂离子电池提出了更高的要求。当下商用锂离子电池负极为石墨，理论容量仅为372mAh/g，极大地限制了锂离子电池的发展。硅基负极材料(硅、氧化亚硅)理论容量高达4200mAh/g，是传统石墨材料的十几倍，且其具有较低的放电平台、资源丰富，是最有希望替代石墨的负极材料之一。然而，在锂化和去锂化的过程中，硅体积发生巨大的膨胀和收缩，破坏电极结构，材料之间失去电接触，导致电池容量剧烈下降、寿命缩短。In recent years, the development of various application fields such as portable electronic products and electric vehicles has put forward higher requirements for high-performance lithium-ion batteries. At present, the negative electrode of commercial lithium-ion batteries is graphite, and the theoretical capacity is only 372mAh/g, which greatly limits the development of lithium-ion batteries. The theoretical capacity of silicon-based anode materials (silicon, silicon oxide) is as high as 4200mAh/g, which is more than ten times that of traditional graphite materials, and it has a lower discharge platform and is rich in resources. It is one of the most promising anode materials to replace graphite. . However, during the process of lithiation and delithiation, the volume of silicon undergoes huge expansion and contraction, which destroys the electrode structure and loses electrical contact between materials, resulting in a dramatic decrease in battery capacity and shortened life.

为了减缓硅的体积膨胀，许多团队在硅的结构方面做出了很大努力。众多策略中，硅碳复合材料比如硅碳核壳结构、硅碳纳米纤维、硅碳多孔或中空结构吸引了更多注意力。原因如下：1)碳材料具有良好的电子迁移率，可以增加材料的导电性；2)碳材料可以缓冲硅的体积膨胀效应，减小硅与电解液的接触，形成稳定的固体电解质膜(SEI)。然而，电极材料使用纳米硅基颗粒导致生产成本高昂，电池能量密度低；生产过程中包含化学气相沉积(CVD)和强酸、强碱腐蚀的步骤也不利于大规模生产。所以，开发一种成本低廉、生产工艺简单的高能量密度锂离子电池仍刻不容缓。In order to slow down the volume expansion of silicon, many teams have made great efforts in the structure of silicon. Among many strategies, silicon-carbon composite materials such as silicon-carbon core-shell structure, silicon-carbon nanofiber, silicon-carbon porous or hollow structure have attracted more attention. The reasons are as follows: 1) carbon materials have good electron mobility, which can increase the conductivity of materials; 2) carbon materials can buffer the volume expansion effect of silicon, reduce the contact between silicon and electrolyte, and form a stable solid electrolyte film (SEI ). However, the use of nano-silicon-based particles as electrode materials leads to high production costs and low battery energy density; the production process includes steps of chemical vapor deposition (CVD) and strong acid and strong alkali corrosion, which are not conducive to large-scale production. Therefore, it is still urgent to develop a high-energy-density lithium-ion battery with low cost and simple production process.

发明内容SUMMARY OF THE INVENTION

本发明的目的是提供一种用于锂离子电池负极的微米硅碳复合材料，解决现有硅碳复合材料能量密度低、生产成本高和过程复杂的问题，基于本发明的复合材料组装的锂离子电池有着良好的循环稳定性和较高的容量，工艺简单，有利于大规模生产。The purpose of the present invention is to provide a micron silicon-carbon composite material for the negative electrode of lithium ion battery, which solves the problems of low energy density, high production cost and complicated process of the existing silicon-carbon composite material. The ion battery has good cycle stability and high capacity, and the process is simple, which is conducive to large-scale production.

为了实现上述目的，本发明提供了以下技术方案：In order to achieve the above object, the present invention provides the following technical solutions:

本发明第一方面提供了一种用于锂离子电池负极的微米硅碳复合材料，所述微米硅碳复合负极材料为核壳结构，包括内部核体、包覆内部核体的第一外壳层和包覆第一外壳层的第二外壳层；其中，所述内部核体的材料包括硅基材料，所述第一外壳层的材料包括导电碳，所述第二外壳层的材料包括碳元素。A first aspect of the present invention provides a micron silicon-carbon composite material for a negative electrode of a lithium ion battery. The micron silicon-carbon composite negative electrode material has a core-shell structure, including an inner core body and a first outer shell layer covering the inner core body. and a second outer shell layer covering the first outer shell layer; wherein, the material of the inner core body includes a silicon-based material, the material of the first outer shell layer includes conductive carbon, and the material of the second outer shell layer includes carbon element .

进一步的，所述硅基材料的颗粒粒径为500nm～100μm。Further, the particle size of the silicon-based material is 500 nm˜100 μm.

进一步的，所述硅基材料包括结晶硅、非结晶硅、硅氧材料中的一种或多种；所述导电碳包括石墨、乙炔黑、碳纳米管和膨胀石墨的一种或多种；所述第二壳层的材料为碳源碳化后形成的碳层。Further, the silicon-based material includes one or more of crystalline silicon, amorphous silicon, and silicon-oxygen materials; the conductive carbon includes one or more of graphite, acetylene black, carbon nanotubes, and expanded graphite; The material of the second shell layer is a carbon layer formed after the carbon source is carbonized.

本发明第二方面提供了所述的微米硅碳复合材料的制备方法，包括以下步骤：A second aspect of the present invention provides the preparation method of the micron silicon-carbon composite material, comprising the following steps:

(1)将微米硅和导电碳球磨，得到前驱体A；将碳源前驱体加入到溶剂中，得到碳源溶液B；(1) Ball milling of micro-silicon and conductive carbon to obtain precursor A; adding carbon source precursor to a solvent to obtain carbon source solution B;

(2)将前驱体A加入到碳源溶液B中，交替搅拌、超声，得到混合均匀的浆料C；(2) Add precursor A to carbon source solution B, alternately stir and sonicate to obtain uniformly mixed slurry C;

(3)在搅拌下，将浆料C加入到表面活性剂的水溶液中定型，过滤、干燥后得到前驱体D；(3) under stirring, the slurry C is added to the aqueous solution of the surfactant to shape, and the precursor D is obtained after filtration and drying;

(4)将前驱体D置于保护气氛中高温碳化处理之后得到所述微米硅碳复合材料。(4) After the precursor D is placed in a protective atmosphere for high-temperature carbonization treatment, the micron silicon-carbon composite material is obtained.

进一步的，所述步骤(3)中，所述表面活性剂为非离子型表面活性剂。Further, in the step (3), the surfactant is a nonionic surfactant.

进一步的，所述表面活性剂选自聚氧乙烯型、多元醇型、烷醇酰胺型、聚醚型、氧化铵型表面活性剂中的任一种；所述表面活性剂在水中的溶解度为0.1wt％～9wt％。Further, the surfactant is selected from any one of polyoxyethylene type, polyol type, alkanolamide type, polyether type, ammonium oxide type surfactant; the solubility of the surfactant in water is 0.1wt% to 9wt%.

进一步的，所述表面活性剂为聚氧乙烯型或者多元醇型。Further, the surfactant is a polyoxyethylene type or a polyol type.

不使用表面活性剂的时候，高温热解碳也可以包覆在硅表面，但这时碳包覆的不完整，仍有部分硅暴露在电解液中。随着锂化和去锂化的进行，硅结构崩塌，不断与电解液反应生成较厚的SEI膜，最终导致电极失效。When no surfactant is used, high-temperature pyrolytic carbon can also be coated on the silicon surface, but at this time the carbon coating is incomplete, and some silicon is still exposed in the electrolyte. With the progress of lithiation and delithiation, the silicon structure collapses and continuously reacts with the electrolyte to form a thicker SEI film, which eventually leads to electrode failure.

当使用表面活性剂时，非离子型表面活性剂亲水端与硅发生氢键作用，疏水端与PAN相互作用，在匀质机的作用下，PAN可以共形地包覆在硅/导电材料上，有效缓解硅的体积膨胀效应，保持电极结构的完整性，从而实现良好的循环稳定性。表面活性剂的加入有助于碳层的共形型包覆，烧结形成含氮的碳壳。再加上导电碳的参与，增加了复合材料的导电性，缓解了锂化过程中硅巨大的体积膨胀效应，最终提高了电池的循环稳定性。When a surfactant is used, the hydrophilic end of the nonionic surfactant is hydrogen-bonded with silicon, and the hydrophobic end interacts with PAN. Under the action of a homogenizer, PAN can be conformally coated on the silicon/conductive material On the other hand, it can effectively alleviate the volume expansion effect of silicon and maintain the integrity of the electrode structure, thereby achieving good cycle stability. The addition of surfactant facilitates the conformal coating of the carbon layer, which sinters to form a nitrogen-containing carbon shell. Coupled with the participation of conductive carbon, the conductivity of the composite is increased, the huge volume expansion effect of silicon during lithiation is alleviated, and the cycling stability of the battery is finally improved.

本发明中表面活性剂的浓度为0.1％～9％，浓度低于0.1％对电极稳定性提升没有明显影响，浓度过高，表面活性剂会发生自团聚，电池的容量会降低。The concentration of the surfactant in the present invention is 0.1% to 9%, and the concentration lower than 0.1% has no obvious effect on the improvement of electrode stability. If the concentration is too high, the surfactant will self-agglomerate and the capacity of the battery will decrease.

进一步的，所述步骤(1)中，微米硅与导电碳的质量比为4:1～1:4。Further, in the step (1), the mass ratio of micro-silicon to conductive carbon is 4:1-1:4.

进一步的，所述步骤(1)中，所述球磨的转速为300～600转/分钟，时间为12～48h，球料比为14:1。Further, in the step (1), the rotational speed of the ball mill is 300-600 rpm, the time is 12-48 h, and the ball-to-material ratio is 14:1.

进一步的，微米硅与导电碳球磨比例为1：1～1:3，比例低于1：1，硅含量过高，电极循环稳定性降低；比例高于1：3，整体电极材料硅含量太少，电极容量下降。Further, the ratio of micron silicon to conductive carbon ball milling is 1:1 to 1:3, if the ratio is lower than 1:1, the silicon content is too high, and the electrode cycle stability is reduced; if the ratio is higher than 1:3, the silicon content of the overall electrode material is too high. less, the electrode capacity decreases.

进一步的，所述步骤(2)中，所述碳源溶液B中的碳源选自聚丙烯腈、葡萄糖、酚醛树脂、环氧树脂、聚苯乙烯、蔗糖中的任意一种。Further, in the step (2), the carbon source in the carbon source solution B is selected from any one of polyacrylonitrile, glucose, phenolic resin, epoxy resin, polystyrene, and sucrose.

进一步的，所述碳源为聚丙烯腈。Further, the carbon source is polyacrylonitrile.

进一步的，所述步骤(2)中，超声时间为1～6h。Further, in the step (2), the ultrasonic time is 1-6h.

进一步的，所述步骤(3)的搅拌为剧烈搅拌，所述剧烈搅拌为磁力搅拌、均质机搅拌、超声搅拌中的任一种。Further, the stirring in the step (3) is vigorous stirring, and the vigorous stirring is any one of magnetic stirring, homogenizer stirring, and ultrasonic stirring.

进一步的，所述搅拌为均质机搅拌。Further, the stirring is a homogenizer stirring.

进一步的，所述步骤(3)中，将浆料C逐滴滴入到表面活性剂的水溶液。Further, in the step (3), the slurry C is dropped dropwise into the aqueous solution of the surfactant.

进一步的，所述步骤(4)中，所述高温碳化处理温度为600～900℃，时间为1～5h，升温速率为3～7℃/min，保护气氛为氩气、氮气、氦气、氖气中一种或多种。Further, in the step (4), the high-temperature carbonization treatment temperature is 600-900°C, the time is 1-5h, the heating rate is 3-7°C/min, and the protective atmosphere is argon, nitrogen, helium, One or more of neon gas.

本发明第三方面提供了所述的微米硅碳复合材料在制备电池中的应用，所述微米硅碳复合材料用于制备锂离子电池负极。The third aspect of the present invention provides the application of the micron silicon-carbon composite material in preparing a battery, and the micron silicon-carbon composite material is used for preparing a negative electrode of a lithium ion battery.

与现有技术相比，本发明的优点和有益效果为：Compared with prior art, advantage and beneficial effect of the present invention are:

1、本发明提供了一种用于锂离子电池负极的微米硅碳复合材料，所述微米硅碳复合材料在表面活性剂辅助下实现共形型碳包覆，可以很好地缓冲硅的体积变化，较少硅和电解液的接触，有利于形成稳定的SEI膜，保持电极的完整性；以本发明材料制备的电极具有良好的循环性能和容量，制得的电池在1A/g的电流密度下循环100次后，比容量为955mAh/g，容量保持在80％。1. The present invention provides a micron silicon-carbon composite material for a negative electrode of a lithium ion battery. The micron silicon-carbon composite material realizes conformal carbon coating with the assistance of a surfactant, which can well buffer the volume of silicon. change, less contact between silicon and electrolyte, which is conducive to the formation of a stable SEI film and maintains the integrity of the electrode; the electrode prepared with the material of the present invention has good cycle performance and capacity, and the prepared battery has a current of 1A/g. After 100 cycles at the density, the specific capacity was 955 mAh/g and the capacity remained at 80%.

2、本发明提供了所述微米硅碳复合材料的制备方法，以微米级硅基材料为原料，使用球磨和表面活性剂辅助的方法形成核壳结构。该材料结构稳定，外部碳壳能有效缓解硅的体积变化，保持电极结构稳定。制备方法可以通过调节前期硅、碳的比例和表面活性剂的浓度，得到不同硅含量和不同碳包覆厚度的微米硅碳复合材料，具有灵活性。2. The present invention provides a method for preparing the micron silicon-carbon composite material, which uses micron-scale silicon-based materials as raw materials, and uses ball milling and surfactant-assisted methods to form a core-shell structure. The material has a stable structure, and the outer carbon shell can effectively alleviate the volume change of silicon and keep the electrode structure stable. The preparation method can obtain micro-silicon-carbon composite materials with different silicon contents and different carbon coating thicknesses by adjusting the ratio of silicon and carbon in the early stage and the concentration of surfactant, which is flexible.

3、本发明的微米硅碳复合材料制备成本低，采用低成本的微米硅降低了电池的原材料成本，涉及到的制备方法不需要很高的技术成本，有利于电池的研究推广。微米硅碳复合材料制备方法简单，没有大的技术难度，制备过程绿色环保，对设备要求低，且不产生有害副产品，制备过程极易实现大规模无害生产。3. The preparation cost of the micro-silicon-carbon composite material of the present invention is low, and the use of low-cost micro-silicon reduces the raw material cost of the battery, and the preparation method involved does not require high technical costs, which is conducive to the research and promotion of batteries. The preparation method of micron silicon-carbon composite material is simple, without great technical difficulty, the preparation process is green and environmentally friendly, has low requirements for equipment, and does not produce harmful by-products. The preparation process is extremely easy to achieve large-scale harmless production.

附图说明Description of drawings

通过阅读参照以下附图对非限制性实施例所作的详细描述，本发明的其它特征、目的和优点将会变得更明显：Other features, objects and advantages of the present invention will become more apparent by reading the detailed description of non-limiting embodiments with reference to the following drawings:

图1为实施例1制备的微米硅碳复合物的SEM和TEM图；Fig. 1 is the SEM and TEM images of the micron silicon-carbon composite prepared in Example 1;

图2为实施例1制备的微米硅碳复合材料用于锂离子电池负极时电池的首圈充放电曲线；Fig. 2 is the charge-discharge curve of the first cycle of the battery when the micron silicon-carbon composite material prepared in Example 1 is used for the negative electrode of the lithium-ion battery;

图3为实施例1制备的微米硅碳复合材料用于锂离子电池负极时电池的循环稳定性，其中，A为循环圈数与比容量的关系图，B为循环次数与比容量的关系图。Figure 3 is the cycle stability of the battery when the micron silicon-carbon composite material prepared in Example 1 is used for the negative electrode of lithium ion battery, wherein, A is the relationship diagram between cycle number and specific capacity, and B is the relationship diagram between cycle number and specific capacity .

具体实施方式Detailed ways

下面结合具体实施例对本发明进行详细说明。以下实施例将有助于本领域的技术人员进一步理解本发明，但不以任何形式限制本发明。应当指出的是，对本领域的普通技术人员来说，在不脱离本发明构思的前提下，还可以做出若干变形和改进。这些都属于本发明的保护范围。The present invention will be described in detail below with reference to specific embodiments. The following examples will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that, for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

实施例1Example 1

1、本实施例提供了一种用于锂离子电池负极的微米硅碳复合材料，其制备方法包括以下步骤：1. This embodiment provides a micron silicon-carbon composite material for the negative electrode of a lithium ion battery, and the preparation method thereof includes the following steps:

(1)将20.75g微米硅和20.75g石墨用581g球磨珠以转速400转/分钟球磨24h，得到Si-G复合材料；(1) 20.75g of micro-silicon and 20.75g of graphite were ball-milled with 581g of ball milling beads at a rotational speed of 400 rpm for 24h to obtain a Si-G composite material;

(2)将7.5g Si-G复合材料加入5wt％聚丙烯腈(PAN)的N,N-二甲基甲酰胺(DMF)溶液中，交替进行搅拌、超声4h，得到均匀混合的悬浮液；(2) Add 7.5g of Si-G composite material into 5wt% polyacrylonitrile (PAN) N,N-dimethylformamide (DMF) solution, alternately stir and sonicate for 4 hours to obtain a uniformly mixed suspension;

(3)然后将上述悬浮液在匀质机搅拌下逐滴滴入到含有0.5wt％的吐温水溶液中定型，过滤干燥；(3) the above-mentioned suspension is then dripped dropwise into the Tween aqueous solution containing 0.5wt% under the stirring of the homogenizer to shape, filter and dry;

(4)最后，在氩气保护下，以5℃/min加热速率加热到700℃，保温2小时，然后自然降温即得所述微米硅碳复合材料。(4) Finally, under the protection of argon gas, heat to 700°C at a heating rate of 5°C/min, keep the temperature for 2 hours, and then naturally cool down to obtain the micron silicon-carbon composite material.

本实施例制备的微米硅碳复合材料的SEM和TEM图如图1所示，碳层共形地包覆在硅的周围，增加材料的导电性，缓解硅的体积变化，保持电极的完整性。The SEM and TEM images of the micro-silicon-carbon composite material prepared in this example are shown in Figure 1. The carbon layer is conformally wrapped around the silicon, which increases the conductivity of the material, alleviates the volume change of silicon, and maintains the integrity of the electrode. .

2、电池的制备2. Preparation of batteries

将本实施例制得的微米硅碳复合材料、CMC粘结剂和导电炭黑按照质量比6:2:2称取样，在分散液中磁力搅拌数小时得到均匀浆料，然后将浆料涂敷在铜箔上，在60℃下烘干，之后将其裁成电极片大小，真空110℃活化3小时得到硅基负极极片。将硅基负极极片与电解液、正极极片、隔膜等装备CR2016扣式电池。The micro-silicon-carbon composite material, CMC binder and conductive carbon black prepared in this example are weighed and sampled according to the mass ratio of 6:2:2, and magnetically stirred in the dispersion for several hours to obtain a uniform slurry, and then the slurry is coated. It was coated on copper foil, dried at 60°C, and then cut into electrode pieces, and activated in vacuum at 110°C for 3 hours to obtain silicon-based negative electrode pieces. The silicon-based negative pole piece, electrolyte, positive pole piece, separator, etc. were equipped with CR2016 button battery.

将装备的电池进行电化学测试，首次充放电平台如图2所示，表现出典型的晶型硅锂化的放电平台。在1A/g电流密度下，所得的循环性能图如图3所示，电池的首圈容量为1397mAh/g，第二圈容量为1192mAh/g，循环100圈后容量可达第二圈的80％。The equipped battery was electrochemically tested, and the first charge and discharge platform was shown in Figure 2, showing a typical crystalline silicon lithiation discharge platform. At a current density of 1A/g, the obtained cycle performance diagram is shown in Figure 3. The capacity of the battery in the first cycle is 1397mAh/g, the capacity in the second cycle is 1192mAh/g, and the capacity can reach 80% of the second cycle after 100 cycles. %.

实施例2Example 2

本实施例与实施例1的区别在于：制备微米硅碳复合材料的步骤(3)中，将0.5wt％的吐温水溶液换成0.1wt％的吐温水溶液，其他条件同实施例1。The difference between this example and Example 1 is that in the step (3) of preparing the micro-silicon-carbon composite material, the 0.5wt% Tween aqueous solution is replaced with a 0.1wt% Tween aqueous solution, and other conditions are the same as those in Example 1.

对本实施例的装备的电池进行电化学测试，电池的首圈容量为1102mAh/g，第二圈容量为884mAh/g，循环100圈之后容量为第6圈的65％。Electrochemical tests were carried out on the battery equipped in this embodiment. The first cycle capacity of the battery was 1102mAh/g, the second cycle capacity was 884mAh/g, and the capacity after 100 cycles was 65% of the sixth cycle.

实施例3Example 3

本实施例与实施例1的区别在于，制备微米硅碳复合材料的步骤(3)中，将0.5wt％的吐温水溶液换成5wt％的吐温水溶液，其他条件同实施例1。The difference between this example and Example 1 is that in the step (3) of preparing the micro-silicon carbon composite material, the 0.5wt% Tween aqueous solution is replaced with a 5wt% Tween aqueous solution, and other conditions are the same as those in Example 1.

对本实施例的装备的电池进行电化学测试，电池的首圈容量为1420mAh/g，第二圈容量为819mAh/g，循环100圈后容量为第6圈的66％。The electrochemical test was carried out on the battery equipped in this example. The capacity of the battery in the first cycle was 1420mAh/g, the capacity in the second cycle was 819mAh/g, and the capacity after 100 cycles was 66% of that in the sixth cycle.

实施例4Example 4

本实施例与实施例1的区别在于：制备微米硅碳复合材料的步骤(3)中，将0.5wt％的吐温水溶液换成10wt％的吐温水溶液，其他条件同实施例1。The difference between this example and Example 1 is that in the step (3) of preparing the micron silicon-carbon composite material, the 0.5wt% Tween aqueous solution is replaced with a 10wt% Tween aqueous solution, and other conditions are the same as those in Example 1.

对本实施例的装备的电池进行电化学测试，电池的首圈容量为1359mAh/g，前30圈容量迅速衰减容量低于500mAh/g。An electrochemical test was carried out on the battery equipped in this embodiment, and the capacity of the first cycle of the battery was 1359mAh/g, and the capacity rapidly decayed in the first 30 cycles and the capacity was lower than 500mAh/g.

以上对本发明的具体实施例进行了描述。需要理解的是，本发明并不局限于上述特定实施方式，本领域技术人员可以在权利要求的范围内做出各种变化或修改，这并不影响本发明的实质内容。在不冲突的情况下，本申请的实施例和实施例中的特征可以任意相互组合。Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above-mentioned specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essential content of the present invention. The embodiments of the present application and features in the embodiments may be combined with each other arbitrarily, provided that there is no conflict.

Claims (10)

Translated fromChinese

1.一种用于锂离子电池负极的微米硅碳复合材料，其特征在于，所述微米硅碳复合负极材料为核壳结构，包括内部核体、包覆内部核体的第一外壳层和包覆第一外壳层的第二外壳层；其中，所述内部核体的材料包括硅基材料，所述第一外壳层的材料包括导电碳，所述第二外壳层的材料包括碳元素。1. A micron silicon-carbon composite material for lithium-ion battery negative pole, characterized in that, said micron silicon-carbon composite negative electrode material is a core-shell structure, comprising an internal core body, a first shell layer covering the internal core body and A second shell layer covering the first shell layer; wherein, the material of the inner core body includes a silicon-based material, the material of the first shell layer includes conductive carbon, and the material of the second shell layer includes carbon element.2.根据权利要求1所述的微米硅碳复合材料，其特征在于，所述硅基材料的颗粒粒径为500nm～100μm。2 . The micron silicon-carbon composite material according to claim 1 , wherein the particle size of the silicon-based material is 500 nm˜100 μm. 3 .3.根据权利要求1所述的微米硅碳复合材料，其特征在于，所述硅基材料包括结晶硅、非结晶硅、硅氧材料中的一种或多种；所述导电碳包括石墨、乙炔黑、碳纳米管和膨胀石墨的一种或多种；所述第二壳层的材料为碳源碳化后形成的碳层。3. The micron silicon-carbon composite material according to claim 1, wherein the silicon-based material comprises one or more of crystalline silicon, amorphous silicon, and silicon-oxygen materials; the conductive carbon comprises graphite, One or more of acetylene black, carbon nanotubes and expanded graphite; the material of the second shell layer is a carbon layer formed after carbonization of a carbon source.4.权利要求1～3任一项所述的微米硅碳复合材料的制备方法，其特征在于，包括以下步骤：4. The preparation method of the micron silicon-carbon composite material according to any one of claims 1 to 3, characterized in that it comprises the following steps:(1)将微米硅和导电碳球磨，得到前驱体A；将碳源前驱体加入到溶剂中，得到碳源溶液B；(1) Ball milling of micro-silicon and conductive carbon to obtain precursor A; adding carbon source precursor to a solvent to obtain carbon source solution B;(2)将前驱体A加入到碳源溶液B中，交替搅拌、超声，得到混合均匀的浆料C；(2) adding the precursor A to the carbon source solution B, alternately stirring and sonicating to obtain a uniformly mixed slurry C;(3)在搅拌下，将浆料C加入到表面活性剂的水溶液中定型，过滤、干燥后得到前驱体D；(3) under stirring, the slurry C is added to the aqueous solution of the surfactant to shape, and the precursor D is obtained after filtration and drying;(4)将前驱体D置于保护气氛中高温碳化处理之后得到所述微米硅碳复合材料。(4) After the precursor D is placed in a protective atmosphere for high-temperature carbonization treatment, the micron silicon-carbon composite material is obtained.5.根据权利要求4所述的微米硅碳复合材料的制备方法，其特征在于，所述步骤(3)中，所述表面活性剂为非离子型表面活性剂。5 . The method for preparing a micron silicon-carbon composite material according to claim 4 , wherein, in the step (3), the surfactant is a nonionic surfactant. 6 .6.根据权利要求5所述的微米硅碳复合材料的制备方法，其特征在于，所述表面活性剂选自聚氧乙烯型、多元醇型、烷醇酰胺型、聚醚型、氧化铵型表面活性剂中的任一种；所述表面活性剂在水中的溶解度为0.1wt％～9wt％。6. The preparation method of micron silicon carbon composite material according to claim 5, wherein the surfactant is selected from the group consisting of polyoxyethylene type, polyol type, alkanolamide type, polyether type, ammonium oxide type Any one of the surfactants; the solubility of the surfactant in water is 0.1 wt % to 9 wt %.7.根据权利要求4所述的微米硅碳复合材料的制备方法，其特征在于，所述步骤(1)中，微米硅与导电碳的质量比为4:1～1:4。7. The preparation method of micron silicon-carbon composite material according to claim 4, characterized in that, in the step (1), the mass ratio of micron silicon to conductive carbon is 4:1˜1:4.8.根据权利要求4所述的微米硅碳复合材料的制备方法，其特征在于，所述步骤(2)中，所述碳源溶液B中的碳源选自聚丙烯腈、葡萄糖、酚醛树脂、环氧树脂、聚苯乙烯、蔗糖中的任意一种。8. the preparation method of micron silicon-carbon composite material according to claim 4 is characterized in that, in described step (2), the carbon source in the described carbon source solution B is selected from polyacrylonitrile, glucose, phenolic resin , epoxy resin, polystyrene, sucrose in any one.9.根据权利要求4所述的微米硅碳复合材料的制备方法，其特征在于，所述步骤(4)中，所述高温碳化处理温度为600～900℃，时间为1～5h，升温速率为3～7℃/min，保护气氛为氩气、氮气、氦气、氖气中一种或多种。9 . The method for preparing a micron silicon-carbon composite material according to claim 4 , wherein, in the step (4), the high temperature carbonization treatment temperature is 600-900° C., the time is 1-5 h, and the heating rate The temperature is 3 to 7°C/min, and the protective atmosphere is one or more of argon, nitrogen, helium, and neon.10.权利要求1～3任一项所述的微米硅碳复合材料在制备电池中的应用，其特征在于，所述微米硅碳复合材料用于制备锂离子电池负极。10. The application of the micro-silicon-carbon composite material according to any one of claims 1 to 3 in the preparation of batteries, characterized in that the micro-silicon-carbon composite material is used to prepare lithium-ion battery negative electrodes.

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