CN103996834B - A kind of silicon based anode material with silane coupler and conducting polymer double-coating structure and preparation method and application - Google Patents

Abstract

The invention discloses a silicon-based negative electrode material with a double-layer covering structure of a silane coupling agent and a conductive polymer, as well as a preparation method and application thereof. The silicon-based negative electrode material is based on elemental silicon, and the substrate is coated with a silane coupling agent modification layer, and the silane coupling agent modification layer is coated with protonic acid-doped conductive polyaniline. The preparation method is: (1 ) Ultrasonic blending of silane coupling agent and silicon powder, reflux at a certain temperature to modify silicon powder; (2) Ultrasonic blending of aniline monomer and modified silicon powder in an acidic solution system, and then carry out In-situ polymerization to obtain a silicon-based composite material coated with a conductive polymer; (3) washing the mixed solution, suction filtration, and vacuum drying to obtain a silicon-based composite material with a double-layer coating structure of a silane coupling agent and a conductive polymer. Based negative electrode materials, which can be used to prepare negative electrode materials for lithium-ion batteries when doped in graphite. The invention is simple and easy to implement, has low manufacturing cost, good reproducibility and is convenient for large-scale industrial production.

Description

A silicon-based negative electrode with a silane coupling agent and a conductive polymer double-layer coating structure Materials and their preparation methods and applications

technical field

The invention belongs to the technical field of lithium-ion battery negative electrode materials and electrochemistry, and relates to a silicon-based negative electrode material with a double-layer coating structure of a silane coupling agent and a conductive polymer, and a preparation method and application thereof.

Background technique

In recent years, compared with traditional secondary batteries such as lead-acid batteries, iron batteries, and nickel-metal hydride batteries, lithium-ion batteries have the advantages of high energy density, high output voltage, low self-discharge, small memory effect, and environmental friendliness, and have gained a lot of attention. Extensive application and research. The performance of key materials for lithium-ion batteries is an important determinant of battery performance, and the development and improvement of negative electrode materials is a global research hotspot. Negative electrode materials such as silicon materials, carbon materials, tin materials, lithium titanate, and metal oxides have been extensively studied. However, the lithium-ion battery system assembled with these negative electrode materials has defects such as poor cycle performance, low specific energy density, high cost, poor safety, and consistency problems, which make it difficult to meet the requirements of power storage batteries.

Silicon-based anode materials have always been the anode materials for lithium-ion batteries due to their theoretical specific capacity exceeding 4200 mAh/g, low lithium intercalation potential, actual specific capacity greater than 3000 mAh/g, abundant content in nature, and relatively low raw material prices. Research hotspots. However, the disadvantages of silicon materials such as low initial Coulombic efficiency, poor rate performance, and poor cycle performance severely inhibit the large-scale application of silicon-based anode materials in lithium-ion batteries.

In order to develop silicon-based anode materials with excellent cycle performance, researchers have developed a variety of technical means to modify and improve silicon materials. Graphite, hard carbon, pitch, carbon nanotubes, nanocarbon fibers, metal nanotubes, etc. have been used to coat silicon-based anode materials. For example, Si ₂ C ₅₂ H ₁₈ with a regular structure was prepared by N. Kurita et al. Compared with C ₅₄ H ₁₈ , this material can intercalate a large number of lithium ions, and its structure will also reduce the irreversible reaction of lithium ion extraction, which has a good cycle performance. N. Dimov et al. used hot gas deposition method to coat a layer of carbon material on the surface of simple silicon, and obtained particles with an average size of 18 μm. The specific capacity was above 600 mAh/g, which was higher than the theoretical specific capacity of carbon material (372 mAh/g). , the cycle performance is equivalent to that of carbon materials, and it is greatly improved compared with elemental silicon. ZS Wen et al. obtained a silicon-carbon composite by pyrolysis of a resin filled with graphite and simple silicon, and its specific capacity reached 800-900 mAh/g. After 20 cycles, its specific capacity was stable at 600 mAh/g. BJNeudecker et al. prepared SiSn _0.87 O _1.20 N _1.72 , the specific capacity is close to 800 mAh/g, and it can still maintain at 600 mAh/g after 10,000 charge-discharge cycles, the discharge voltage is 4.1-2.7V, and the irreversible capacity loss per cycle is 0.002% However, the high cost hinders its commercialization process.

Silane coupling agent is the earliest researched and applied coupling agent, which has the advantages of less dosage and low cost. Since the silane coupling agent has two types of chemical groups X and R in the molecule, R is an organic functional group that can be combined with a polymer; X is a hydrolyzable group that can react with the hydroxyl group in the silicon surface oxide layer. Therefore, the interaction between the silane coupling agent between the polymer and the inorganic system plays the role of coupling.

Therefore, there is an urgent need to find a simple and feasible modification method and preparation method of silicon-based negative electrode materials, so that silicon-based negative electrode materials have both high first-time Coulombic efficiency and good cycle stability, so as to meet the power requirements. battery requirements.

Contents of the invention

The purpose of the present invention is to provide a silicon-based negative electrode material with a silane coupling agent and a conductive polymer double-layer coating structure and its preparation method and application. The silane coupling agent is used to modify the silicon powder. The silane coupling agent is located in the The conductive polymer organic coating layer plays a bridge role with the inorganic system substrate of silicon powder. The method is simple and easy, has low manufacturing cost, good reproducibility, and is convenient for large-scale industrial production.

The purpose of the present invention is achieved through the following technical solutions:

A silicon-based negative electrode material with a double-layer coating structure of a silane coupling agent and a conductive polymer, with simple silicon as the base, coated with a silane coupling agent modification layer outside the substrate, and the silane coupling agent modification layer is coated on the outside Conductive polyaniline with proton acid doping state.

A method for preparing the above-mentioned silicon-based negative electrode material having a silane coupling agent and a double-layer coating structure of a conductive polymer, the steps are as follows:

(1) Ultrasonic blending of silane coupling agent and silicon powder, reflux at a certain temperature, and modification of silicon powder; Among them: the preparation method of silicon powder is gas phase method, sol-gel method, precipitation method, microemulsion method and ball milling method; the particle size range of silicon powder is between 20 and 2000 nm; the silane coupling agent is γ-aminopropyltriethoxysilane, γ-(2,3-glycidoxy ) Propyltrimethoxysilane, γ-(Methacryloyloxy)propyltrimethoxysilane, Octyltriethoxysilane, Dimethyldimethoxysilane, Methyltributylketoximosilane, A type of isocyanate propyltriethoxysilane; the amount of silane coupling agent added is 0.01-10% of the mass fraction of silicon powder; the reflux temperature is 40-120°C, and the reflux time is 1-24 h;

(2) Ultrasonic blending of aniline monomer and modified silicon powder in an acid solution system of protonic acid, and then adding ammonium persulfate for in-situ polymerization to obtain a silicon-based composite material coated with a conductive polymer; Among them: the protonic acid is hydrochloric acid, dodecylbenzenesulfonic acid, camphorsulfonic acid, p-toluenesulfonic acid, methanesulfonic acid, n-butyl/ethyl phosphoric acid, n-decyl phosphoric acid, benzyl phosphoric acid, benzoic acid A mixture of one or more of them; the polymerization temperature is 0-10°C, the mass ratio of ammonium persulfate to aniline is 1:2-1:4, and the mass ratio of modified silicon powder to aniline is 4 :1-1:1, the polymerization reaction time is 4-10 h.

(3) Wash the mixed solution, suction filter, and vacuum dry to obtain a silicon-based negative electrode material with a double-layer coating structure of a silane coupling agent and a conductive polymer; wherein: the vacuum drying temperature is 45-55°C, and the vacuum drying The time is 10-12 h.

The silicon-based negative electrode material with a silane coupling agent and a conductive polymer double-layer coating structure prepared by the above method can be doped in graphite, and the silicon-based negative electrode material with a silane coupling agent and a conductive polymer double-layer coating structure It accounts for 1~98% of the graphite content.

The present invention modifies silicon powder with a silane coupling agent to form a modified layer on the surface of the silicon substrate, and then generates a conductive polymer coating layer on the surface. Due to the bridge effect of the silane coupling agent, the conductive polymerization of the silicon substrate and the outermost layer The tight combination of materials can effectively prevent the expansion and pulverization effect of silicon, so that the silicon-based negative electrode material has a high first-time Coulombic efficiency and good cycle stability, so as to meet the requirements of power batteries.

The advantages of the present invention are as follows:

(1) Modification of elemental silicon with a silane coupling agent to form the first coating layer, and a tightly bonded conductive polymer coating layer is formed on the outer surface in situ, which improves the first Coulombic efficiency and cycle stability of silicon-based negative electrode materials, and can meet Power battery requirements.

(2) The modification process is applicable to all silicon-based anode materials, and is simple and easy to operate, with low manufacturing cost and good reproducibility, and is convenient for large-scale industrial production.

(3) Compared with the silicon-based negative electrode of the prior art, the silicon-based negative electrode of the present invention has a higher specific capacity, especially the cycle performance of the existing silicon negative electrode has been greatly improved. After being doped in graphite, the graphite negative electrode The performance of the material has been greatly improved.

(4) The silicon-based negative electrode material prepared in the present invention has an infrared spectrum as shown in Figure 5, and its characteristic peaks are 2972cm ^-1 , 2926cm ^-1 and 1735cm ^-1 .

Description of drawings

Fig. 1 is the schematic diagram of the reaction between silane coupling agent and elemental silicon substrate;

Fig. 2 is the reaction device schematic diagram of in-situ polymerization;

Fig. 3 is the SEM picture of the silicon-based negative electrode material before silane coupling agent modification;

Fig. 4 is the SEM picture of the silicon-based negative electrode material (embodiment 1) of silane coupling agent and conductive polymer double-layer coating structure;

Fig. 5 is the infrared spectrogram of the silicon-based negative electrode material with silane coupling agent coating;

Figure 6 is a cycle performance curve of a silicon-based negative electrode material (Example 4) with a silane coupling agent and a conductive polymer double-layer coating structure;

Fig. 7 is a graphical representation of the cycle performance of a silicon-based anode material with a double-layer coating structure of a conductive polymer.

detailed description

The present invention is further described below through examples and comparative examples. These examples are only used to illustrate the present invention, and the present invention is not limited to the following examples. Any modification or equivalent replacement of the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention shall be included in the protection scope of the present invention.

Example 1:

1. Mix 0.1g of γ-(methacryloyloxy)propyltrimethoxysilane with 45mL of ethanol and 5mL of water in a three-necked flask for hydrolysis, add 4.9g of silicon powder, and mix ultrasonically for 0.5h; at an air flow rate of 200mL /min, temperature at 80°C, reflux for 10 h under magnetic stirring conditions, and vacuum drying at 55°C for 12 h to finally obtain γ-(methacryloyloxy)propyltrimethoxysilane surface-modified with a mass concentration of 2%. Silicon-based anode materials. The schematic diagram of the reaction between the silane coupling agent and the elemental silicon substrate is shown in Figure 1. Starting from the elemental silicon substrate, the first cladding layer is a silane coupling agent modification layer, and the second cladding layer is a proton-acid-doped conductive polymer. aniline. The infrared spectrum of the coating layer with silane coupling agent is shown in Figure 5, and absorption peaks appear at 2972 and 2926 cm ^-1 , which correspond to the stretching vibration of the CH bond.

2. Ultrasonic blend 0.045g of aniline monomer and 0.2g of modified silicon powder in 30mL of 3.1% by volume hydrochloric acid system for 0.5 h, the ultrasonic power is 1.5w/cm, the ultrasonic frequency is 30kHz, and then heated at 0-5℃ 30 mL of a 1.5% by volume sulfuric acid solution containing 0.0216 g of ammonium persulfate was added dropwise, and in-situ polymerization was carried out in the reaction device shown in Figure 2, and the polymerization reaction time was 10 h.

3. Wash the mixed solution in step 2 alternately with distilled water and ethanol for 2-3 times, suction filter, and vacuum-dry to obtain a silicon-based negative electrode material with a double-layer coating structure of a silane coupling agent and a conductive polymer, and use a circulating water pump After suction filtration, vacuum-dry at a temperature of 60°C and a drying time of 12 h.

In the comparative example, the agglomeration of silicon powder is relatively serious (as shown in Figure 3), while the prepared silicon-based negative electrode material with a double-layer coating structure of silane coupling agent and conductive polymer is a sphere with complete particles (as shown in Figure 4), the agglomeration situation Relief was obtained, and the particle size was about 20-8000 nm.

It can be seen from the cycle performance curve of the silicon-based negative electrode material with the silane coupling agent coating layer structure in Figure 7 that the initial charge capacity of the material is 2271.2 mAh/g, the initial charge-discharge efficiency is 69.8%, and the charge capacity after 200 cycles is 1441.48mAh/g , the capacity remains around 1400 mAh/g, which has excellent performance.

Example 2:

1. Mix 0.25g of γ-(methacryloyloxy)propyltrimethoxysilane with 45mL of ethanol and 5mL of water in a three-neck flask for hydrolysis, add 4.75g of silicon powder, and mix ultrasonically for 0.5h; at an air flow rate of 200mL /min, temperature at 80°C, reflux for 10 h under magnetic stirring conditions, and vacuum drying at 55°C for 12 h to finally obtain γ-(methacryloyloxy)propyltrimethoxysilane surface-modified with a mass concentration of 5%. Silicon-based anode materials.

2. Ultrasonic blend 0.045 g of aniline monomer and 0.2 g of modified silicon powder in 30 mL of 3.1% by volume hydrochloric acid system for 0.5 h, the ultrasonic power is 1.5 w/cm, the ultrasonic frequency is 30 kHz, and then heated at 0-5 ° C 30 mL of a 3.1% by volume hydrochloric acid solution containing 0.0216 g of ammonium persulfate was added dropwise to carry out in-situ polymerization, and the polymerization reaction time was 10 h.

3. Wash the mixed solution in step 2 alternately with distilled water and ethanol for 2-3 times, suction filter, and vacuum-dry to obtain a silicon-based negative electrode material with a double-layer coating structure of a silane coupling agent and a conductive polymer, and use a circulating water pump After suction filtration, vacuum-dry at a temperature of 60°C and a drying time of 12 h.

It can be seen from the cycle performance curve of the silicon-based negative electrode material with the silane coupling agent coating layer structure in Figure 7 that the initial charge capacity of the material is 2156.14 mAh/g, the initial charge-discharge efficiency is 70.2%, and the charge capacity after 200 cycles is 1553.28mAh/g , the capacity remains at about 1550 mAh/g, which has excellent performance.

Example 3:

1. Mix 0.1g of γ-(methacryloyloxy)propyltrimethoxysilane with 45mL of ethanol and 5mL of water in a three-necked flask for hydrolysis, add 4.9g of silicon powder, and mix ultrasonically for 0.5h; at an air flow rate of 200mL /min, temperature at 80°C, reflux for 10 h under magnetic stirring conditions, and vacuum drying at 55°C for 12 h to finally obtain γ-(methacryloyloxy)propyltrimethoxysilane surface-modified with a mass concentration of 2%. Silicon-based anode materials.

2. Ultrasonic blend 0.09g of aniline monomer and 0.2g of modified silicon powder in 30mL of 3.1% by volume hydrochloric acid system for 0.5 h, the ultrasonic power is 1.5w/cm, the ultrasonic frequency is 30kHz, and then heated at 0-5℃ 30 mL of a 3.1% by volume hydrochloric acid solution containing 0.0432 g of ammonium persulfate was added dropwise to carry out in-situ polymerization, and the polymerization reaction time was 10 h.

3. Wash the mixed solution in step 2 alternately with distilled water and ethanol for 2-3 times, suction filter, and vacuum-dry to obtain a silicon-based negative electrode material with a double-layer coating structure of a silane coupling agent and a conductive polymer, and use a circulating water pump After suction filtration, vacuum-dry at a temperature of 60°C and a drying time of 12 h.

It can be seen from the cycle performance curve of the silicon-based negative electrode material with the silane coupling agent coating layer structure in Figure 7 that the initial charge capacity of the material is 1893.61 mAh/g, the initial charge-discharge efficiency is 71.7%, and the charge capacity after 200 cycles is 1201.83mAh/g , the capacity remains around 1200 mAh/g, which has excellent performance.

Example 4:

1. Mix 0.25g of γ-(2,3-glycidyloxypropoxy)propyltrimethoxysilane in a three-necked flask of 45mL of ethanol and 5mL of water for hydrolysis, add 4.75g of silicon powder, and mix ultrasonically for 0.5h; 200mL/min, temperature 80°C, reflux for 10 h under magnetic stirring conditions, and vacuum drying at 55°C for 12 h to finally obtain γ-(2,3-glycidyloxy)propyltrimethoxy with a mass concentration of 5%. Silane-surface-modified silicon-based anode materials.

2. Ultrasonic blend 0.09g of aniline monomer and 0.2g of modified silicon powder in 30mL of 3.1% by volume hydrochloric acid system for 0.5 h, the ultrasonic power is 1.5w/cm, the ultrasonic frequency is 30kHz, and then heated at 0-5℃ 30 mL of a 3.1% by volume hydrochloric acid solution containing 0.0432 g of ammonium persulfate was added dropwise to carry out in-situ polymerization, and the polymerization reaction time was 10 h.

3. Wash the mixed solution in step 2 alternately with distilled water and ethanol for 2-3 times, suction filter, and vacuum-dry to obtain a silicon-based negative electrode material with a double-layer coating structure of a silane coupling agent and a conductive polymer, and use a circulating water pump After suction filtration, vacuum-dry at a temperature of 60°C and a drying time of 12 h.

It can be seen from the cycle performance curve of the silicon-based negative electrode material with the silane coupling agent coating layer structure in Figure 7 that the initial charge capacity of the material is 1797.67 mAh/g, the initial charge and discharge efficiency is 68.9%, and the charge capacity after 200 cycles is 1295.05 mAh/g , the capacity remains around 1300 mAh/g, which has excellent performance.

Example 5:

1. Mix 0.25g of γ-(methacryloyloxy)propyltrimethoxysilane with 45mL of ethanol and 5mL of water in a three-neck flask for hydrolysis, add 4.75g of silicon powder, and mix ultrasonically for 0.5h; at an air flow rate of 200mL /min, temperature at 80°C, reflux for 10 h under magnetic stirring conditions, and vacuum drying at 55°C for 12 h to finally obtain γ-(methacryloyloxy)propyltrimethoxysilane surface-modified with a mass concentration of 5%. Silicon-based anode materials.

2. Ultrasonic blend 0.045 g of aniline monomer and 0.2 g of modified silicon powder in 30 mL of 3.1% by volume hydrochloric acid system for 0.5 h, the ultrasonic power is 1.5 w/cm, the ultrasonic frequency is 30 kHz, and then heated at 0-5 ° C 30 mL of a 3.1% by volume hydrochloric acid solution containing 0.0216 g of ammonium persulfate was added dropwise to carry out in-situ polymerization, and the polymerization reaction time was 10 h.

3. Wash the mixed solution in step 2 alternately with distilled water and ethanol for 2-3 times, suction filter, and vacuum-dry to obtain a silicon-based negative electrode material with a double-layer coating structure of a silane coupling agent and a conductive polymer, and use a circulating water pump After suction filtration, vacuum-dry at a temperature of 60°C and a drying time of 12 h.

4. Add the silicon-based negative electrode material with a silane coupling agent and a conductive polymer double-layer coating structure prepared in step (3) to 20% by mass and mix it with graphite to obtain a high-capacity, good cycle performance anode materials for lithium-ion batteries.

It can be seen from the cycle performance curve of the silicon-based negative electrode material with a silane coupling agent and a conductive polymer double-layer coating structure in Figure 7 that the initial charge capacity of the material is 728.83mAh/g, the initial charge-discharge efficiency is 87.00%, and the charge after 200 cycles The capacity is 648.43 mAh/g, and the capacity remains around 650mAh/g, which has excellent performance.

Embodiment 6:

1. Mix 0.25g of γ-(methacryloyloxy)propyltrimethoxysilane with 45mL of ethanol and 5mL of water in a three-neck flask for hydrolysis, add 4.75g of silicon powder, and mix ultrasonically for 0.5h; at an air flow rate of 200mL /min, temperature at 80°C, reflux for 10 h under magnetic stirring conditions, and vacuum drying at 55°C for 12 h to finally obtain γ-(methacryloyloxy)propyltrimethoxysilane surface-modified with a mass concentration of 5%. Silicon-based anode materials.

2. Ultrasonic blend 0.045 g of aniline monomer and 0.2 g of modified silicon powder in 30 mL of 3.1% by volume hydrochloric acid system for 0.5 h, the ultrasonic power is 1.5 w/cm, the ultrasonic frequency is 30 kHz, and then heated at 0-5 °C 30 mL of a 3.1% by volume hydrochloric acid solution containing 0.0216 g of ammonium persulfate was added dropwise to carry out in-situ polymerization, and the polymerization reaction time was 10 h.

3. Wash the mixed solution in step 2 alternately with distilled water and ethanol for 2-3 times, suction filter, and vacuum-dry to obtain a silicon-based negative electrode material with a double-layer coating structure of a silane coupling agent and a conductive polymer, and use a circulating water pump After suction filtration, vacuum-dry at a temperature of 60°C and a drying time of 12 h. The mass ratio of copper-modified silicon powder to aniline is 4:1.

4. Mix the silicon-based negative electrode material prepared in step (3) with a double-layer coating structure of silane coupling agent and conductive polymer with graphite at a ratio of 50%.

It can be seen from the cycle performance curve of the silicon-based negative electrode material with a silane coupling agent and a conductive polymer double-layer coating structure in Figure 7 that the initial charge capacity of the material is 1264.07 mAh/g, the initial charge-discharge efficiency is 77.2%, and the charge after 200 cycles The capacity is 1083.66 mAh/g, and the capacity remains around 1080 mAh/g, which has excellent performance.

The comparative example is an untreated elemental silicon material.

The test conditions of each embodiment and comparative example are compared as shown in Table 1.

Table 1

Claims (9)

1. a silicon based anode material with silane coupler and conducting polymer double-coating structure, it is characterised in that described Silicon based anode material, with elemental silicon as substrate, is coated with silane coupler decorative layer in substrate, outside silane coupler decorative layer It is coated with protonic acid doping state electrically conductive polyaniline;

The preparation method of the described silicon based anode material with silane coupler and conducting polymer double-coating structure, specifically walks Rapid as follows:

(1) silane coupler and silica flour are carried out ultrasonic being blended, reflux at a temperature of 40-120 DEG C, silica flour is modified；Its In: the addition of silane coupler is the 0.01-10% of silica flour mass fraction；

(2) silica flour after aniline monomer and modification is carried out ultrasonic being blended in the acid solution system of Bronsted acid, be subsequently adding Ammonium persulfate., carries out in-situ polymerization, obtains being coated with the silicon based composite material of conducting polymer；Wherein: Ammonium persulfate. and aniline The ratio of addition quality be 1:2-1:4, the silica flour after modification is 4:1-1:1 with the mass ratio of aniline；

(3) by described mixed solution washing, sucking filtration, vacuum drying, obtain that there is silane coupler and conducting polymer bilayer bag Cover the silicon based anode material of structure；

Described Bronsted acid be DBSA, camphorsulfonic acid, p-methyl benzenesulfonic acid, pyrovinic acid, normal-butyl/ethyl phosphonic acid, The mixture of one or more in n-decane base phosphoric acid, benzyl phosphoric acid, benzoic acid.

2. described in a claim 1, there is silane coupler and the silicon based anode material of conducting polymer double-coating structure Preparation method, it is characterised in that described method step is as follows:

(1) silane coupler and silica flour are carried out ultrasonic being blended, reflux at a temperature of 40-120 DEG C, silica flour is modified；Its In: the addition of silane coupler is the 0.01-10% of silica flour mass fraction；

(2) silica flour after aniline monomer and modification is carried out ultrasonic being blended in the acid solution system of Bronsted acid, be subsequently adding Ammonium persulfate., carries out in-situ polymerization, obtains being coated with the silicon based composite material of conducting polymer；Wherein: Ammonium persulfate. and aniline The ratio of addition quality be 1:2-1:4, the silica flour after modification is 4:1-1:1 with the mass ratio of aniline；

(3) by described mixed solution washing, sucking filtration, vacuum drying, obtain that there is silane coupler and conducting polymer bilayer bag Cover the silicon based anode material of structure.

The silicon based anode material with silane coupler and conducting polymer double-coating structure the most according to claim 2 Preparation method, it is characterised in that the preparation method of described silica flour be vapor phase method, sol-gal process, the sedimentation method, microemulsion method, The one of ball-milling method.

4. according to described in Claims 2 or 3, there is silane coupler and the silicon-based anode of conducting polymer double-coating structure The preparation method of material, it is characterised in that the particle size interval scope of described silica flour is between 20 to 2000 nm.

The silicon based anode material with silane coupler and conducting polymer double-coating structure the most according to claim 2 Preparation method, it is characterised in that described silane coupler is γ aminopropyl triethoxysilane, γ-(2,3-epoxy third Oxygen) propyl trimethoxy silicane, γ (methacryloxypropyl) propyl trimethoxy silicane, octyltri-ethoxysilane, diformazan Base dimethoxysilane, methyl tributanoximo silane, the one of isocyanatopropyl triethoxysilane.

The silicon based anode material with silane coupler and conducting polymer double-coating structure the most according to claim 2 Preparation method, it is characterised in that described return time is 1-24 h.

The silicon based anode material with silane coupler and conducting polymer double-coating structure the most according to claim 2 Preparation method, it is characterised in that described polymeric reaction temperature is 0-10 DEG C, and polymerization reaction time is 4-10 h.

The silicon based anode material with silane coupler and conducting polymer double-coating structure the most according to claim 2 Preparation method, it is characterised in that described vacuum drying temperature is 45-55 DEG C, and the vacuum drying time is 10-12 h.

9. the silicon based anode material doping with silane coupler and conducting polymer double-coating structure described in claim 1 The application of the negative material of lithium ion battery is prepared in graphite.