Silicon-carbon negative electrode material with high ionic conductivity as well as preparation method and application of silicon-carbon negative electrode material

Abstract

The invention provides a silicon-carbon negative electrode material with high ionic conductivity and a preparation method and application thereof, and relates to the technical field of battery negative electrode materials, the silicon-carbon negative electrode material comprises an ordered mesoporous carbon matrix, a silicon material and a solid electrolyte material; the silicon material is uniformly distributed in mesopores of the ordered mesoporous carbon matrix; the solid electrolyte material is arranged on the surface of the ordered mesoporous carbon matrix or doped in the ordered mesoporous carbon matrix. The silicon-carbon negative electrode material provided by the invention has high ionic conductivity, is suitable for all-solid-state batteries, semi-solid-state batteries and other application scenes, and has a uniform mesoporous structure, so that the volume expansion of silicon is effectively relieved; silicon and carbon are tightly combined, so that the cycling stability of the material is improved; the preparation process is simplified, the production cost is reduced, and industrial popularization is easy.

Description

Technical Field

[0001] The present invention relates to the technical field of battery negative electrode materials, and in particular to a silicon-carbon negative electrode material with high ionic conductivity, a preparation method thereof, and applications thereof. Background Art

[0002] Lithium-ion batteries have been widely used in consumer electronics, electric vehicles, and energy storage systems due to their high energy density, long cycle life, and environmental friendliness. As one of the core components of lithium-ion batteries, the performance of the negative electrode material directly affects the overall performance of the battery. Although the widely used graphite negative electrode material has good cycle stability and cost advantages, its theoretical specific capacity is only 372mAh / g, which is difficult to meet the growing demand for high energy density. In contrast, silicon (Si) material is regarded as an ideal choice for the next generation of high-energy-density lithium-ion battery negative electrode material due to its theoretical specific capacity of up to 4200mAh / g and abundant natural resource reserves. However, silicon material will produce a volume expansion of about 300% during the charge and discharge process. This characteristic can easily lead to material pulverization, electrode structure damage, and electrical contact failure, which seriously affects the cycle life and rate performance of the battery.

[0003] To effectively address the volume expansion problem of silicon materials, academia and industry have proposed a variety of solutions, among which silicon-carbon composites show significant application prospects. Carbon materials, due to their excellent electrical conductivity and mechanical stability, can not only effectively buffer the volume changes of silicon, but also significantly improve the electrical conductivity of electrodes. However, existing silicon-carbon composites still face the following technical bottlenecks: the interface between silicon and carbon is not firmly bonded, resulting in the shedding of silicon particles during cycling; the material structure design is unreasonable, making it impossible to fully utilize the high capacity characteristics of silicon; and the preparation process is complex, making large-scale production difficult.

[0004] In recent years, mesoporous materials have attracted much attention due to their high specific surface area, adjustable pore size distribution, and excellent structural stability. Introducing mesoporous structures into silicon-carbon composites can not only effectively alleviate the volume expansion effect of silicon, but also provide more channels for lithium ion transmission, thereby improving the material's cycle stability and rate performance. Although studies have attempted to apply mesoporous structures to silicon-carbon composites, the following technical challenges still exist: the composite material has low ionic conductivity and an uneven mesoporous structure, resulting in unstable performance; the distribution of silicon and carbon is uneven, affecting the overall performance of the material; the preparation process is complex and the cost is high, making it difficult to achieve industrial production. Solving these problems is of great significance for promoting the practical application of silicon-carbon composites.

[0005] In view of this, the present invention is proposed. Summary of the Invention

[0006] One of the objectives of the present invention is to provide a silicon-carbon negative electrode material with high ionic conductivity to at least solve one of the technical problems existing in the prior art. The silicon-carbon negative electrode material provided by the present invention has high ionic conductivity and is suitable for application scenarios such as all-solid-state batteries and semi-solid-state batteries. In addition, the silicon-carbon negative electrode material provided by the present invention has a uniform mesoporous structure, which effectively alleviates the volume expansion of silicon; the close combination of silicon and carbon improves the cyclic stability of the material; the present invention also simplifies the preparation process, reduces production costs, and is easy to promote industrialization.

[0007] A second object of the present invention is to provide a method for preparing a silicon-carbon negative electrode material with high ionic conductivity.

[0008] The third object of the present invention is to provide a silicon-carbon negative electrode material with high ionic conductivity or a silicon-carbon negative electrode material with high ionic conductivity prepared by a preparation method of a silicon-carbon negative electrode material with high ionic conductivity, and to use the same in the preparation of battery negative electrodes.

[0009] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are adopted:

[0010] In a first aspect, the present invention provides a silicon-carbon negative electrode material with high ionic conductivity, comprising: an ordered mesoporous carbon matrix, a silicon material, and a solid electrolyte material;

[0011] The silicon material is uniformly distributed in the mesopores of the ordered mesoporous carbon matrix;

[0012] The solid electrolyte material is arranged on the surface of the ordered mesoporous carbon matrix or doped inside the ordered mesoporous carbon matrix.

[0013] In some preferred embodiments, the pore volume of the ordered mesoporous carbon matrix is ​​0.01 to 2 cm 3 / g, more preferably 0.6 to 1.1 cm 3 / g;

[0014] The median particle size of the ordered mesoporous carbon matrix is ​​5 to 20 μm, more preferably 6 to 12 μm;

[0015] The diameter pitch of the ordered mesoporous carbon matrix is ​​0.8 to 2.0, and more preferably 0.8 to 1.2.

[0016] In some preferred embodiments, the ordered mesoporous carbon matrix has pore channels and pore wall stripes.

[0017] In some preferred embodiments, the silicon content of the silicon-carbon negative electrode material is 5 to 90%, more preferably 30 to 60%;

[0018] The specific surface area of ​​the silicon-carbon negative electrode material is 0.1 to 50 m 2 / g, more preferably 0.5 to 10 m 2 / g;

[0019] The pore volume of the silicon-carbon negative electrode material is 0.001 to 0.1 cm 3 / g, more preferably 0.001 to 0.05 cm 3 / g;

[0020] The true density of the silicon-carbon negative electrode material measured by helium specific gravity is 1.3-2.0 g / cm 3 , the closed pore volume is 0.01~0.25cm 3 / g;

[0021] The median particle size of the silicon-carbon negative electrode material is 5 to 20 μm, more preferably 6 to 12 μm;

[0022] The diameter pitch of the silicon-carbon negative electrode material is 0.8 to 2.0, more preferably 0.8 to 1.2.

[0023] In a second aspect, the present invention provides a method for preparing a silicon-carbon negative electrode material with high ionic conductivity, comprising the following steps:

[0024] A mixture of a carbon source and a template agent is used as a precursor agent, and the precursor agent is sequentially subjected to optional balling treatment, curing treatment, carbonization treatment, and activation treatment to obtain an ordered mesoporous carbon matrix. Silicon is then deposited on the ordered mesoporous carbon matrix by vapor deposition to obtain a silicon-carbon negative electrode material with high ionic conductivity;

[0025] The solid electrolyte material is added to the mixed solution of the carbon source and the template agent, or the solid electrolyte material is applied in a process after the activation treatment.

[0026] In some preferred embodiments, the carbon source comprises phenolic resin;

[0027] Preferably, the carbon source preparation step comprises: dispersing an aldehyde material, a phenolic material, and a catalyst in water to obtain a phenolic resin mixture;

[0028] Preferably, the preparation temperature of the carbon source is 40-100°C;

[0029] Preferably, the aldehyde material includes one or more of formaldehyde, acetaldehyde and furfural;

[0030] Preferably, the phenolic material comprises one or more of phenol and resorcinol;

[0031] Preferably, the mass of the aldehyde material accounts for 60%-130% of the mass of the phenolic material;

[0032] Preferably, the catalyst comprises one or more of an acidic catalyst and a basic catalyst;

[0033] Preferably, the mass of the catalyst accounts for 1%-5% of the mass of the phenols;

[0034] Preferably, the acidic catalyst comprises one or more of hydrochloric acid, sulfuric acid and oxalic acid;

[0035] Preferably, the alkaline catalyst includes one or more of sodium hydroxide, calcium hydroxide and ammonia water.

[0036] In some preferred embodiments, the step of preparing the precursor agent includes: mixing a template agent, a carbon source, a solvent and a solid electrolyte material to obtain a precursor agent;

[0037] Preferably, the mass ratio of the carbon source, the template agent and the solvent is 1:0.5-2.0:0.1-4.0;

[0038] Preferably, the preparation temperature of the precursor agent is 30-70°C, and the stirring time is 0.5-24h;

[0039] Preferably, the template agent is obtained by polycondensation of polyoxyethylene, polyoxypropylene and polystyrene;

[0040] Preferably, the template agent includes one or more of PEO-PPO-PEO, PPO-PEO-PPO and PEO-PS-PEO;

[0041] Preferably, the molecular weight of the template agent is 1500-40000;

[0042] Preferably, the PEO-PPO-PEO template agent includes one or more of F127, F188 and P123;

[0043] Preferably, the solvent comprises one or more of dimethyl sulfoxide, tetrahydrofuran, ethanol and methanol.

[0044] In some preferred embodiments, the addition amount of the solid electrolyte material is 0.5%-20% of the mass of the phenolic resin, preferably 1%-10%;

[0045] Preferably, the solid electrolyte material includes one or more of an oxide solid electrolyte, a sulfide solid electrolyte, a polymer solid electrolyte, a composite solid electrolyte and a halide solid electrolyte;

[0046] Preferably, the oxide solid electrolyte comprises one or more of lithium lanthanum zirconium oxide, lithium aluminum titanium phosphate and lithium superion conductor;

[0047] Preferably, the sulfide solid electrolyte includes one or more of lithium phosphorus sulfur, lithium germanium phosphorus sulfur and lithium phosphorus sulfur chlorine;

[0048] Preferably, the polymer solid electrolyte comprises one or more of polyethylene oxide, polyvinylidene fluoride and polyacrylonitrile;

[0049] Preferably, the composite solid electrolyte includes one or both of a PEO-LLZO composite electrolyte and a PVDF-LGPS composite electrolyte;

[0050] Preferably, the halide solid electrolyte includes one or both of Li3YCl6 and Li2ZrCl6.

[0051] In some preferred embodiments, the spheronization process adopts an oil phase emulsion polymerization method;

[0052] Preferably, the pelletizing step comprises: mixing a precursor agent, silicone oil and heat transfer oil and then separating them to obtain solid particles;

[0053] Preferably, the mass ratio of the precursor agent, silicone oil and thermal oil is 1:1-5:1-10;

[0054] Preferably, the silicone oil includes one or both of dimethyl silicone oil and phenyl silicone oil;

[0055] Preferably, the viscosity of the silicone oil is 10-1000 cst, more preferably 100-600 cst;

[0056] Preferably, the heat transfer oil comprises one or both of aromatic heat transfer oil and silicone heat transfer oil;

[0057] Preferably, the viscosity of the heat transfer oil is 20-100 cst, more preferably 20-60 cst;

[0058] Preferably, the curing temperature is 80-200°C and the curing time is 3-24h;

[0059] Preferably, the temperature of the carbonization treatment is 500-1000°C, and the time of the carbonization treatment is 0.5-100h;

[0060] Preferably, the temperature of the activation treatment is 500-1000°C, and the time of the activation treatment is 0.5-50h;

[0061] Preferably, the medium used in the activation treatment includes one or more of CO2, water and O2;

[0062] Preferably, when the solid electrolyte material is added after the activation treatment, the method further includes a sintering treatment after the solid electrolyte material is added;

[0063] Preferably, the sintering treatment temperature is 500-1100°C.

[0064] In a third aspect, the present invention provides a silicon-carbon negative electrode material with high ionic conductivity or a silicon-carbon negative electrode material with high ionic conductivity prepared by a method for preparing a silicon-carbon negative electrode material with high ionic conductivity, and its application in preparing a battery negative electrode.

[0065] Compared with the prior art, the present invention has the following beneficial effects:

[0066] The present invention provides a silicon-carbon negative electrode material with high ionic conductivity. By adding a solid electrolyte material to an ordered mesoporous carbon matrix, it has a high lithium ion conductivity and can significantly improve the ion transmission efficiency in the porous carbon. Because after the solid electrolyte fills the pores of the porous carbon, a continuous ion transmission channel is formed, the ion transmission path is shortened, the ion transmission rate is increased, and the rate performance is further improved, which has a good prospect for application in the field of all-solid-state batteries. In addition, the present invention provides a method for preparing a silicon-carbon negative electrode material with high ionic conductivity. A template is added during the preparation process to prepare a uniform mesoporous structure, which effectively alleviates the volume expansion of silicon. The present invention utilizes a template with regular pores (F127, etc.) to guide the directional filling or assembly of the carbon precursor, and then removes the template to obtain an ordered pore structure. By vapor-depositing silicon on the ordered mesoporous carbon matrix, silicon and carbon are tightly combined, thereby improving the cyclic stability of the material. The preparation method solves the problems of silicon volume expansion, weak interface bonding, and complex preparation process in the prior art by optimizing the preparation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0067] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0068] Figure 1 TEM image of the ordered mesoporous carbon matrix in Example 1;

[0069] Figure 2 This is the adsorption-desorption curve of the ordered mesoporous carbon matrix in Example 1. DETAILED DESCRIPTION

[0070] Unless otherwise defined herein, scientific and technical terms used in conjunction with the present invention shall have the meanings commonly understood by those of ordinary skill in the art. The meaning and scope of the terms should be clear; however, in the event of any potential ambiguity, the definitions provided herein take precedence over any dictionary or external definitions. In this application, the use of "or" means "and / or" unless otherwise stated. In addition, the use of the term "including" and other forms is non-limiting.

[0071] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0072] The first aspect of the present invention provides a silicon-carbon negative electrode material with high ionic conductivity, comprising: an ordered mesoporous carbon matrix, a silicon material and a solid electrolyte material; the silicon material is evenly distributed in the mesopores of the ordered mesoporous carbon matrix; the solid electrolyte material is arranged on the surface of the ordered mesoporous carbon matrix or doped inside the ordered mesoporous carbon matrix.

[0073] Since silicon has low ionic conductivity and its structure results in a poor Li+ transmission path, a solid electrolyte is added in the present invention to increase ionic conductivity. The solid electrolyte is doped inside or on the surface of the mesoporous carbon matrix, and silicon is uniformly deposited on the inner wall of the orderly distributed mesopores.

[0074] In an optional embodiment, the pore volume of the ordered mesoporous carbon matrix is ​​0.01 to 2 cm 3 / g, for example, it can be 0.01cm 3 / g, 0.1cm 3 / g, 0.5cm 3 / g, 1cm 3 / g, 1.5cm 3 / g, 2cm 3 / g, etc., more preferably 0.6 to 1.1 cm 3 / g, for example, it can be 0.6cm 3 / g, 0.7cm 3 / g, 0.8cm 3 / g, 0.9cm 3 / g, 1.0cm 3 / g, 1.1cm 3 / g etc.;

[0075] The median particle size (d V,50) is 5 to 20 μm, for example, 5 μm, 8 μm, 10 μm, 12 μm, 14 μm, 16 μm, 18 μm, 20 μm, etc.; more preferably, it is 6 to 12 μm, for example, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, etc.;

[0076] The diameter pitch of the ordered mesoporous carbon matrix is ​​0.8 to 2.0, for example, it can be 0.8, 1.0, 1.2, 1.4, 1.6, 1.8, 2.0, etc.; more preferably, it is 0.8 to 1.2, for example, it can be 0.8, 0.9, 1.0, 1.1, 1.2, etc.

[0077] In the present invention, the diameter distance is (d V,90 -d V,10 ) / d V,50 .

[0078] In an optional embodiment, the ordered mesoporous carbon matrix has pore channels and pore wall stripes.

[0079] In the present invention, Figure 1 As shown in Figure 2, the ordered mesoporous carbon matrix has obvious pores and pore wall stripes in TEM, indicating that it has orderly distributed mesopores, such as Figure 2 As shown, the adsorption isotherm curve has a significant increase at p / p0 = 0.5-0.7, and the proportion of P / P0>0.75 is less than 15%, preferably less than 3%. The purpose of P / P0>0.75 less than 15% is to limit the proportion of pores 10nm. Macropores store electrolyte but have a low contribution to Li+ transport. Local enrichment of electrolyte leads to concentration polarization. On the other hand, a high proportion of macropores increases stress concentration points during material cycling, leading to structural collapse caused by volume change. The proportion of macropores in mesoporous carbon is less than 3%, which significantly improves rate performance by shortening ion paths, enhancing structural stability, and optimizing electronic conduction.

[0080] In an optional embodiment, the silicon content of the silicon-carbon negative electrode material is 5% to 90%, for example, it can be 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, etc., more preferably 30% to 60%;

[0081] The specific surface area of ​​the silicon-carbon negative electrode material is 0.1 to 50 m 2 / g, for example, it can be 0.1m 2 / g, 0.5m 2 / g、1m 2 / g、5m 2 / g、10m 2 / g、15m 2 / g, 20m 2 / g, 25m 2 / g、30m 2 / g、35m 2 / g, 40m 2 / g、45m 2 / g, 50m 2 / g, etc., more preferably 0.5 to 10 m 2 / g, for example, it can be 0.5m 2 / g、1m 2 / g, 1.5m 2 / g, 2m 2 / g, 2.5m 2 / g、3m 2 / g, 3.5m 2 / g、4m 2 / g, 4.5m 2 / g、5m 2 / g, etc.

[0082] The pore volume of the silicon-carbon negative electrode material is 0.001 to 0.1 cm 3 / g, for example, it can be 0.001cm 3 / g, 0.005cm 3 / g, 0.01cm 3 / g, 0.05cm 3 / g, 0.1cm 3 / g, etc.; more preferably 0.001 to 0.05 cm 3 / g, for example, it can be 0.001cm 3 / g, 0.005cm 3 / g, 0.01cm 3 / g, 0.02cm 3 / g, 0.03cm 3 / g, 0.04cm 3 / g, 0.05cm 3 / g, etc.

[0083] The true density of the silicon-carbon negative electrode material measured by helium specific gravity is 1.3-2.0 g / cm 3 , for example, it can be 1.3g / cm 3 , 1.4g / cm 3 , 1.5g / cm 3 , 1.6g / cm 3 , 1.7g / cm 3 , 1.8g / cm 3 , 1.9g / cm 3 , 2.0g / cm 3 etc.; closed pore volume is 0.01~0.25cm 3 / g, for example, it can be 0.01cm 3 / g, 0.05cm 3 / g, 0.1cm 3 / g, 0.2cm 3 / g, 0.25cm 3 / g etc.;

[0084] The median particle size d of the silicon-carbon negative electrode material V,50 5 to 20 μm, for example, 5 μm, 8 μm, 10 μm, 12 μm, 14 μm, 16 μm, 18 μm, 20 μm, etc., more preferably 6 to 12 μm, for example, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 11 μm, 12 μm, etc.;

[0085] The diameter distance (d V,90 -d V,10 ) / d V,50 It is 0.8 to 2.0, for example, 0.8, 1.0, 1.2, 1.4, 1.6, 1.8, 2.0, etc.; more preferably, it is 0.8 to 1.2, for example, 0.8, 0.9, 1.0, 1.1, 1.2, etc.

[0086] A second aspect of the present invention provides a method for preparing a silicon-carbon negative electrode material with high ionic conductivity, comprising the following steps:

[0087] A mixture of a carbon source and a template agent is used as a precursor agent, and the precursor agent is sequentially subjected to optional balling treatment, curing treatment, carbonization treatment, and activation treatment to obtain an ordered mesoporous carbon matrix. Silicon is then deposited on the ordered mesoporous carbon matrix by vapor deposition to obtain a silicon-carbon negative electrode material with high ionic conductivity;

[0088] The solid electrolyte material is added to the mixed solution of the carbon source and the template agent or is applied in a process after the activation treatment. Preferably, the application process is a physical mixing process.

[0089] In the present invention, the solid electrolyte may be doped during the precursor stirring step, or after carbonization.

[0090] In an alternative embodiment, the carbon source comprises phenolic resin;

[0091] Preferably, the carbon source preparation step comprises: dispersing an aldehyde material, a phenolic material, and a catalyst in water to obtain a phenolic resin mixture;

[0092] Preferably, the preparation temperature of the carbon source is 40-100°C, for example, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, etc.;

[0093] Preferably, the aldehyde material includes one or more of formaldehyde, acetaldehyde and furfural;

[0094] Preferably, the phenolic material comprises one or more of phenol and resorcinol;

[0095] Preferably, the mass of the aldehyde material accounts for 60%-130% of the mass of the phenolic material, for example, it can be 60%, 70%, 80%, 90%, 100%, 110%, 120%, 130%, etc.;

[0096] Preferably, the catalyst comprises one or more of an acidic catalyst and a basic catalyst;

[0097] Preferably, the mass of the catalyst accounts for 1%-5% of the mass of the phenols, for example, it can be 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, etc.;

[0098] Preferably, the acidic catalyst comprises one or more of hydrochloric acid, sulfuric acid and oxalic acid;

[0099] Preferably, the alkaline catalyst includes one or more of sodium hydroxide, calcium hydroxide and ammonia water.

[0100] In an optional embodiment, the addition amount of the solid electrolyte material is 0.5%-20% of the mass of the phenolic resin, for example, it can be 0.5%, 1%, 5%, 10%, 15%, 20%, etc., preferably 1%-10%, for example, it can be 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, etc.;

[0101] Preferably, the solid electrolyte material includes one or more of an oxide solid electrolyte, a sulfide solid electrolyte, a polymer solid electrolyte, a composite solid electrolyte and a halide solid electrolyte; multiple solid electrolytes can be selected simultaneously to act synergistically.

[0102] Preferably, the oxide solid electrolyte comprises LLZO (lithium lanthanum zirconium oxide, Li7La3Zr2O 12 ), LATP (lithium aluminum titanium phosphate, Li 1+X Al X Ti 2-X (PO4)3), LISICON (lithium superion conductor, such as Li14Zn(GeO4)4);

[0103] Preferably, the sulfide solid electrolyte includes LPS (lithium phosphorus sulfur, Li3PS4), LGPS (lithium germanium phosphorus sulfur, Li 10 GeP2S 12), one or more of lithium phosphorus sulfur chlorine (Li6PS5Cl).

[0104] Preferably, the polymer solid electrolyte includes one or more of PEO (Polyethylene Oxide), PVDF (Polyvinylidene Fluoride), and PAN (Polyacrylonitrile).

[0105] Preferably, the composite solid electrolyte includes one or both of a PEO-LLZO composite electrolyte and a PVDF-LGPS composite electrolyte;

[0106] Preferably, the halide solid electrolyte includes one or both of Li3YCl6 and Li2ZrCl6.

[0107] In an optional embodiment, the step of preparing the precursor agent includes: mixing a template agent, a carbon source and a solvent to obtain a precursor agent;

[0108] Preferably, the mass ratio of the carbon source, the template agent and the solvent is 1:0.5-2.0:0.1-4.0; wherein, the pore size in the mesoporous carbon can be adjusted by adjusting the proportion of the triblock copolymer.

[0109] The “0.5-2” may be, for example, 0.5, 1, 1.5, 2, etc.;

[0110] The “0.1-4.0” here can be, for example, 0.1, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, etc.

[0111] Preferably, the preparation temperature of the precursor agent is 30-70°C, for example, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, etc., and the stirring time is 0.5-24h, for example, 0.5h, 1h, 1.5h, 2h, 4h, 6h, 8h, 10h, 12h, 16h, 18h, 24h, etc.;

[0112] Preferably, the template agent is obtained by polycondensation reaction of hydrophilic polyoxyethylene (PEO), hydrophobic polyoxypropylene (PPO), and polystyrene (PS);

[0113] Preferably, the template agent includes one or more of PEO-PPO-PEO, PPO-PEO-PPO and PEO-PS-PEO;

[0114] Preferably, the molecular weight of the template agent is 1500-40000;

[0115] Preferably, the PEO-PPO-PEO template agent includes one or more of F127, F188 and P123;

[0116] Preferably, the solvent comprises one or more of dimethyl sulfoxide, tetrahydrofuran, ethanol and methanol.

[0117] In an optional embodiment, the spheroidization process adopts an oil phase emulsion polymerization method;

[0118] Preferably, the pelletizing step comprises: mixing a precursor agent, silicone oil and heat transfer oil and then separating them to obtain solid particles;

[0119] Preferably, the mass ratio of the precursor agent, silicone oil and thermal oil is 1:1-5:1-10;

[0120] Here, "1-5" can be, for example, 1, 2, 3, 4, 5, etc.;

[0121] Among them, "1-10" can be, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, etc.

[0122] Preferably, the silicone oil includes one or both of dimethyl silicone oil and phenyl silicone oil;

[0123] Preferably, the viscosity of the silicone oil is 10-1000 cst, more preferably 100-600 cst;

[0124] Preferably, the heat transfer oil comprises one or both of aromatic heat transfer oil and silicone heat transfer oil;

[0125] Preferably, the viscosity of the heat transfer oil is 20-100 cst, more preferably 20-60 cst;

[0126] Preferably, the curing temperature is 80-200°C, for example, 80°C, 100°C, 120°C, 140°C, 160°C, 180°C, 200°C, etc., and the curing time is 3-24h, for example, 3h, 5h, 8h, 10h, 12h, 14h, 16h, 18h, 20h, 24h, etc.;

[0127] Preferably, the temperature of the carbonization treatment is 500-1000° C., for example, 500° C., 600° C., 700° C., 800° C., 900° C., 1000° C., etc., and the time of the carbonization treatment is 0.5-100 h, for example, 0.5 h, 1 h, 5 h, 8 h, 10 h, 30 h, 50 h, 80 h, 100 h, etc.;

[0128] Preferably, the activation treatment temperature is 500-1000° C., for example, 500° C., 600° C., 700° C., 800° C., 900° C., 1000° C., etc., and the activation treatment time is 0.5-50 h, for example, 0.5 h, 1 h, 3 h, 5 h, 10 h, 20 h, 30 h, 40 h, 50 h, etc.;

[0129] Preferably, the medium used in the activation treatment includes one or more of CO2, water and O2;

[0130] Preferably, when the solid electrolyte material is added after the activation treatment, the method further includes a sintering treatment after the solid electrolyte material is added;

[0131] Preferably, the sintering treatment temperature is 500-1100°C, for example, 500°C, 700°C, 900°C, 1100°C, etc.; preferably 700-900°C, for example, 700°C, 750°C, 800°C, 850°C, 900°C, etc.

[0132] In the present invention, the method for preparing the silicon-carbon negative electrode material with high ionic conductivity comprises the following steps:

[0133] (1) Preparation of carbon source: A certain proportion of aldehyde, phenol and catalyst are dispersed in water, and a uniform phenolic resin mixture is prepared at 40-100°C. The mixture is then distilled under reduced pressure to remove excess water to obtain phenolic resin (i.e., carbon source).

[0134] (2) Preparation of the precursor: Stirring the template agent, carbon source, solvent, and solid electrolyte material at 30-70° C. for 0.5-24 hours to obtain a uniform mixed solution;

[0135] (3) A certain amount of precursor agent, silicone oil, and heat transfer oil are stirred in a container for 2 to 48 hours, and then solid-liquid separation is performed to obtain particles;

[0136] (4) placing the above particles into a tube furnace and sequentially performing curing treatment, carbonization treatment and activation treatment to obtain an ordered mesoporous carbon matrix;

[0137] (5) Silicon is deposited on the ordered mesoporous carbon matrix using vapor deposition to obtain a silicon-carbon negative electrode material with high ionic conductivity.

[0138] The third aspect of the present invention provides a silicon-carbon negative electrode material with high ionic conductivity or a silicon-carbon negative electrode material with high ionic conductivity prepared by a method for preparing a silicon-carbon negative electrode material with high ionic conductivity, and its application in preparing battery negative electrodes, especially lithium batteries.

[0139] The silicon-carbon anode material provided by the present invention addresses existing issues such as silicon volume expansion, weak interfacial bonding, and complex preparation processes by optimizing the material's structural design and preparation process. The silicon-carbon anode material of the present invention has the following advantages: a uniform mesoporous structure that effectively mitigates silicon volume expansion; a close bond between silicon and carbon that improves the material's cyclic stability; a simplified preparation process that reduces production costs and facilitates industrialization; and high ionic conductivity, making it suitable for applications in all-solid-state and semi-solid-state batteries.

[0140] In the present invention, ordered mesoporous carbon provides more active sites and faster ion transport channels than microporous carbon. Its high conductivity and structural stability also enhance electronic conduction and cycling stability. Good interfacial compatibility also helps form a stable SEI film, reducing side reactions and thus improving overall battery performance. Mesoporous carbon materials can effectively mitigate volume changes during charge and discharge, reducing pulverization and shedding of electrode materials and extending battery life.

[0141] The solid electrolyte (such as LATP) in the present invention has a high lithium ion conductivity (usually 10 -4 to 10 -3 S / cm range), can significantly improve the ion transport efficiency in porous carbon. This is because after the solid electrolyte fills the pores of the porous carbon, a continuous ion transport channel is formed, shortening the ion transport path, increasing the ion transport rate, and further improving the rate performance, which has good prospects for application in the field of all-solid-state batteries.

[0142] The present invention is further described below by way of examples. Unless otherwise specified, the materials in the examples were prepared according to existing methods or directly purchased from the market.

[0143] Example 1

[0144] This embodiment provides a silicon-carbon negative electrode material with high ionic conductivity, and a preparation method thereof includes the following steps:

[0145] (1) Preparation of the carbon source: 40 g of formaldehyde, 34.45 g of phenol, and 0.34 g of a catalyst (specifically, hydrochloric acid) were dispersed in water and prepared into a uniform phenolic resin mixture at 70° C. The mixture was then distilled under reduced pressure to remove excess water, thereby obtaining a phenolic resin (i.e., a carbon source);

[0146] (2) Preparation of the precursor: Phenolic resin, F127, and ethanol were mixed in a mass ratio of 1:0.5:0.5, and 1% LATP (based on the mass of the resin) was added and stirred in a container at 50°C for 4 h to obtain a precursor;

[0147] (3) stirring a precursor agent, silicone oil (specifically dimethyl silicone oil), and heat transfer oil (specifically aromatic heat transfer oil) in a mass ratio of 1:1:4 in a container for 25 hours, and then performing solid-liquid separation to obtain particles;

[0148] (4) The above particles were placed in an oven and heated to 150°C for 10 hours, then placed in a tube furnace and heated to 500°C for carbonization for 3 hours, and then kept warm at 800°C for 3 hours using steam to obtain a pore volume of 0.82 cm 3 / g, specific surface area is 1079m 2 / g, with an average pore size of 3.3nm, and an ordered mesoporous carbon matrix containing solid electrolyte LATP was obtained;

[0149] (5) The above powder was placed in a tube furnace, and the temperature was raised from room temperature to 550°C at 5°C / min in an N2 atmosphere, and then changed to a 25% SiH4-N2 mixed gas, and kept at 550°C for 15 hours in the mixed atmosphere for Si deposition; then the temperature was changed to a 25% C2H4-N2 mixed atmosphere and kept at 550°C for 8 hours, and then changed to an N2 atmosphere and cooled naturally, crushed and graded to obtain a silicon-carbon negative electrode material; the true density of the silicon-carbon negative electrode material measured by the helium specific gravity method was 1.5 g / cm 3 , the closed pore volume is 0.09 cm 3 / g; the pore volume of the silicon-carbon negative electrode material is 0.01cm 3 / g; the silicon content in the obtained silicon-carbon negative electrode material is 50.50wt.%, and the specific surface area is 2.40m 2 / g, median particle size d V,50 is 12.2μm, and the diameter distance (d V,90 -d V,10 ) / d V,50 The obtained silicon-carbon negative electrode material was used to prepare a buckle to characterize the electrochemical performance.

[0150] Example 2

[0151] This embodiment provides a silicon-carbon negative electrode material with high ionic conductivity. The difference between its preparation method and that of embodiment 1 is that in step (2), 1.5% LATP (based on the mass of the resin) is added and stirred in a container for 4 hours; after carbonization and activation, a pore volume of 0.76 cm 3 / g, the specific gravity is 1105m 2 / g, a uniform mesoporous carbon material with an average pore size of 3.1nm; the true density of the silicon-carbon negative electrode material measured by helium specific gravity is 1.3g / cm 3 , the closed pore volume is 0.02cm 3 / g; the pore volume of the silicon-carbon negative electrode material is 0.03cm 3 / g; the silicon content in the silicon-carbon negative electrode material obtained after silicon deposition is 49.84wt.%, and the specific surface area is 1.78m 2 / g, median particle size d V,50 is 11.4μm, and the diameter distance (d V,90 -d V,10 ) / d V,50 The obtained silicon-carbon negative electrode material was prepared and charged to characterize the electrochemical performance.

[0152] Example 3

[0153] This embodiment provides a silicon-carbon negative electrode material with high ionic conductivity. The difference between its preparation method and that of Example 1 is that in step (2), 1% LLZO (based on the mass of the resin) is added and stirred in a container for 4 hours. After carbonization and activation, a pore volume of 0.80 cm 3 / g, the specific gravity is 1078m 2 / g, a uniform mesoporous carbon material with an average pore size of 2.9nm; the true density of the silicon-carbon negative electrode material measured by helium specific gravity method is 1.7g / cm 3 , the closed pore volume is 0.04 cm 3 / g; the pore volume of the silicon-carbon negative electrode material is 0.007cm 3 / g; The silicon content of the silicon-carbon negative electrode material obtained after silicon deposition is 49.90wt.%, and the specific surface area is 1.28m 2 / g, median particle size d V,50 is 10.3 μm, and the diameter distance (d V,90 -d V,10 ) / d V,50 The obtained silicon-carbon negative electrode material was used to prepare a buckle to characterize the electrochemical performance.

[0154] Example 4

[0155] This embodiment provides a silicon-carbon negative electrode material with high ionic conductivity. The difference between its preparation method and that of Example 1 is that in step (2), 1.5% LLZO (based on the mass of the resin) is added and stirred in a container for 4 hours. After carbonization and activation, a pore volume of 0.87 cm 3 / g, the specific gravity is 1208m 2 / g, a uniform mesoporous carbon material with an average pore size of 3.5nm; the true density of the silicon-carbon negative electrode material measured by helium specific gravity method is 1.7g / cm3, and the closed pore volume is 0.10cm 3 / g; the pore volume of the silicon-carbon negative electrode material is 0.03cm 3 / g; the silicon content in the silicon-carbon negative electrode material obtained after silicon deposition is 50.24wt.%, and the specific surface area is 2.10m 2 / g, median particle size d V,50 is 9.1μm, and the diameter distance (dV,90 -d V,10 ) / d V,50 is 1.03, and the obtained silicon-carbon negative electrode material is used to prepare a buckle to characterize the electrochemical performance.

[0156] Example 5

[0157] This embodiment provides a silicon-carbon negative electrode material with high ionic conductivity. The difference between its preparation method and that of Example 1 is that in step (2), 10% LLZO (based on the mass of the resin) is added and stirred in a container for 4 hours. After carbonization and activation, a pore volume of 0.80 cm 3 / g, the specific gravity is 1078m 2 / g, a uniform mesoporous carbon material with an average pore size of 2.9nm; the true density of the silicon-carbon negative electrode material measured by helium specific gravity is 1.8g / cm 3 , the closed pore volume is 0.13cm 3 / g; the pore volume of the silicon-carbon negative electrode material is 0.007cm 3 / g; the silicon content in the silicon-carbon negative electrode material obtained after silicon deposition is 49.90wt.%, and the specific surface area is 1.28m 2 / g, median particle size d V,50 is 10.3 μm, and the diameter distance (d V,90 -d V,10 ) / d V,50 The obtained silicon-carbon negative electrode material was used to prepare a buckle to characterize the electrochemical performance.

[0158] Example 6

[0159] This embodiment provides a silicon-carbon negative electrode material with high ionic conductivity. The difference between its preparation method and that of Example 1 is:

[0160] In step (1), phenol is 34.45 g, formaldehyde is 40 g, the catalyst is 0.34 g, and the preparation temperature is 40°C;

[0161] In step (2), the mass ratio of phenolic resin, F127, and ethanol is 1:2:0.1, and 0.5% LLZO (based on the mass of the resin) is added, and stirred at 30°C for 24 hours;

[0162] In step (3), the mass ratio of the precursor agent, silicone oil and thermal oil is 1:1:4, and stirring is carried out for 2 hours;

[0163] In step (4), the above particles were placed in an oven and heated to 150°C for curing for 10 hours, and then placed in a tube furnace and heated to 500°C for carbonization for 100 hours. After that, they were kept warm at 800°C for 50 hours using steam to obtain a pore volume of 0.60 cm 3 / g, with a specific surface area of ​​824m 2 / g, with an average pore size of 3.60nm, and an ordered mesoporous carbon matrix containing solid electrolyte LLZO was obtained;

[0164] Step (5): The same as step (5) of Example 1; the true density of the silicon-carbon negative electrode material measured by helium specific gravity method is 1.4 g / cm 3 , the closed pore volume is 0.03cm 3 / g; the pore volume of the silicon-carbon negative electrode material is 0.003cm 3 / g; the silicon content in the obtained silicon-carbon negative electrode material is 50.18wt.%, and the specific surface area is 1.37m 2 / g, median particle size d V,50 is 8.1μm, and the diameter distance (d V,90 -d V,10 ) / d V,50 is 1.15;

[0165] The remaining steps are consistent with those in Example 1.

[0166] Example 7

[0167] This embodiment provides a silicon-carbon negative electrode material with high ionic conductivity. The difference between its preparation method and that of Example 1 is:

[0168] In step (1), phenol is 34.45 g, formaldehyde is 40 g, the catalyst is 0.34 g, and the preparation temperature is 100°C;

[0169] In step (2), the mass ratio of phenolic resin, F127, and ethanol is 1:0.5:0.5, and 20% LLZO (based on the mass of the resin) is added and stirred at 70°C for 0.5 hours;

[0170] In step (3), the mass ratio of the precursor agent, silicone oil and thermal oil is 1:1:10, and stirring is carried out for 48 hours;

[0171] In step (4), the above particles were placed in a tube furnace, heated to 1000°C for carbonization for 0.5 hours, and then kept warm at 1000°C for 0.5 hours using steam to obtain a pore volume of 0.85 cm 3 / g, specific surface area is 1357m 2 / g, with an average pore size of 3.1nm, and an ordered mesoporous carbon matrix containing solid electrolyte LLZO was obtained;

[0172] Step (5): The same as step (5) of Example 1; the true density of the silicon-carbon negative electrode material measured by helium specific gravity method is 1.5 g / cm 3 , the closed pore volume is 0.12cm 3 / g; the pore volume of the silicon-carbon negative electrode material is 0.013cm 3 / g; The silicon content of the obtained silicon-carbon negative electrode material is 49.20wt.%, and the specific surface area is 0.90m 2 / g, median particle size d V,50 is 8.4μm, and the diameter distance (d V,90 -d V,10 ) / d V,50 is 1.03;

[0173] The remaining steps are consistent with those in Example 1.

[0174] Example 8

[0175] This embodiment provides a silicon-carbon negative electrode material with high ionic conductivity. The difference between its preparation method and that of Example 1 is:

[0176] In step (1), phenol is 34.45 g, formaldehyde is 40 g, and the catalyst is 0.34 g;

[0177] In step (2), the mass ratio of phenolic resin, F127, and ethanol is 1:0.4:4, and 0.4% LLZO (based on the mass of the resin) is added;

[0178] In step (3), the mass ratio of the precursor agent, silicone oil and thermal oil is 1:1:4;

[0179] After carbonization activation in step (4), the pore volume is 0.01 cm 3 / g, and a specific surface area of ​​1.03m 2 / g, with an average pore size of 0nm, and an ordered mesoporous carbon matrix containing solid electrolyte LLZO was obtained;

[0180] Step (5): The same as step (5) of Example 1; the true density of the silicon-carbon negative electrode material measured by helium specific gravity method is 1.63 g / cm 3 , the closed pore volume is 0.012cm 3 / g; the pore volume of the silicon-carbon negative electrode material is 0.014cm 3 / g; the silicon content in the obtained silicon-carbon negative electrode material is 0.10wt.%, and the specific surface area is 0.78m 2 / g, median particle size d V,50 is 8.1μm, and the diameter distance (d V,90 -d V,10 ) / d V,50 is 1.09;

[0181] The remaining steps are consistent with those in Example 1.

[0182] Example 9

[0183] This embodiment provides a silicon-carbon negative electrode material with high ionic conductivity. The difference between its preparation method and that of Example 1 is:

[0184] In step (1), phenol is 34.45 g, formaldehyde is 40 g, and the catalyst is 0.34 g;

[0185] In step (2), the mass ratio of phenolic resin, F127, and ethanol is 1:2:0.05, and 21% LLZO (based on the mass of the resin) is added;

[0186] In step (3), the mass ratio of the precursor agent, silicone oil and thermal oil is 1:1:4;

[0187] After carbonization activation in step (4), the pore volume is 0.53 cm 3 / g, specific surface area is 649m 2 / g, with an average pore size of 3.3nm, and an ordered mesoporous carbon matrix containing solid electrolyte LLZO was obtained;

[0188] Step (5): The same as step (5) of Example 1; the true density of the silicon-carbon negative electrode material measured by helium specific gravity method is 1.62 g / cm 3 , the closed pore volume is 0.021cm 3 / g; the pore volume of the silicon-carbon negative electrode material is 0.023cm 3 / g; the silicon content in the obtained silicon-carbon negative electrode material is 0.06wt.%, and the specific surface area is 0.54m 2 / g, median particle size d V,50 is 8.9μm, and the diameter distance (d V,90 -d V,10 ) / d V,50 is 1.14;

[0189] The remaining steps are consistent with those in Example 1.

[0190] Example 10

[0191] This embodiment provides a silicon-carbon negative electrode material with high ionic conductivity. The difference between its preparation method and that of Example 1 is that the solid electrolyte material is added between the carbonization treatment and the activation treatment, and no ball-forming process is performed.

[0192] (1) Preparation of the carbon source: 40 g of formaldehyde, 34.45 g of phenol, and 0.34 g of a catalyst (specifically, hydrochloric acid) were dispersed in water, and a uniform phenolic resin mixture was prepared at 40-100° C. The mixture was then distilled under reduced pressure to remove excess water, thereby obtaining a phenolic resin (i.e., a carbon source);

[0193] (2) Preparation of the precursor: Phenolic resin, F127, and ethanol were mixed at a mass ratio of 1:0.5:0.5 and stirred in a container at 50°C for 4 h to obtain a precursor;

[0194] (4) The above particles were placed in an oven and heated to 150°C for curing for 10 hours, and then placed in a tube furnace and heated to 500°C for carbonization for 3 hours. After that, water vapor was used to keep the temperature at 800°C for 3 hours to obtain a pore volume of 0.85 cm 3 / g, specific surface area is 1295m 2 / g, an ordered mesoporous carbon matrix with an average pore size of 3.3nm, and then 0.5% LLZO (based on the resin mass) was added, mixed evenly, and sintered at 900°C for 3 hours to obtain an ordered mesoporous carbon matrix containing a solid electrolyte;

[0195] (5) The above powder was placed in a tube furnace, and the temperature was raised from room temperature to 550°C at 5°C / min in an N2 atmosphere, and then changed to a 25% SiH4-N2 mixed gas, and kept at 550°C for 15 hours in the mixed atmosphere for Si deposition; then the temperature was changed to a 25% C2H4-N2 mixed atmosphere and kept at 550°C for 8 hours, and then changed to an N2 atmosphere and cooled naturally, crushed and graded to obtain a silicon-carbon negative electrode material; the true density of the silicon-carbon negative electrode material measured by the helium specific gravity method was 1.7 g / cm 3 , the closed pore volume is 0.02cm 3 / g; the pore volume of the silicon-carbon negative electrode material is 0.019cm 3 / g; the silicon content in the obtained silicon-carbon negative electrode material is 50.24wt.%, and the specific surface area is 1.35m 2 / g, median particle size d V,50 is 9.04μm, and the diameter distance (d V,90 -d V,10 ) / d V,50 is 1.06, and the obtained silicon-carbon negative electrode material is used to prepare a buckle to characterize the electrochemical performance;

[0196] The remaining steps are consistent with those in Example 1.

[0197] Comparative Example 1

[0198] This comparative example provides a silicon-carbon negative electrode material, the preparation method of which comprises the following steps:

[0199] (1) Phenolic resin was cured at 150 °C for 10 h, the solid was crushed, and carbonized at 400 °C for 2 h in an inert gas atmosphere, and then treated at 800 °C for 3 h in a steam atmosphere to obtain a specific surface area of ​​1900 m 2 / g, pore volume is 0.83cm 3 / g, porous carbon framework material with an average pore size of 2nm;

[0200] Step 2: The above materials were heated from room temperature to 550°C at 5°C / min in an N2 atmosphere, and then changed to a 25% SiH4-N2 mixed gas, and kept at 550°C for 15 hours in the mixed atmosphere for Si deposition; then changed to a 25% C2H4-N2 mixed atmosphere and kept at 550°C for 8 hours, and then changed to an N2 atmosphere and cooled naturally, crushed and graded to obtain a silicon-carbon negative electrode material; the true density of the silicon-carbon negative electrode material measured by the helium specific gravity method was 1.5g / cm 3 , the closed pore volume is 0.05cm 3 / g; the pore volume of the silicon-carbon negative electrode material is 0.014cm 3 / g; the silicon content in the obtained silicon-carbon negative electrode material is 50.15wt.%, and the specific surface area is 1.68m 2 / g, median particle size d V,50 is 8.0 μm, and the diameter distance (d V,90 -d V,10 ) / d V,50 The obtained silicon-carbon negative electrode material was prepared and charged to characterize the electrochemical performance.

[0201] Comparative Example 2

[0202] This comparative example provides a silicon-carbon negative electrode material, and its preparation method differs from that of Example 3 in that:

[0203] In step (2), no solid electrolyte material is added, and the remaining steps are consistent with those in Example 3.

[0204] Test Case

[0205] Electrode, half-cell preparation and electrochemical performance testing:

[0206] The silicon-based composite materials prepared in the above examples and comparative examples were used as negative electrode active materials to prepare negative electrode sheets. The negative electrode sheets were used to prepare CR2032 button batteries using conventional methods, and the batteries were tested for electrical performance. The specific testing methods are as follows:

[0207] (1) Half-cell assembly: CR2032 button cells were assembled in a glove box, with a lithium metal sheet as the counter electrode, a polypropylene microporous membrane as the separator, and the electrolyte being a mixture of LiPF6 dissolved in ethyl carbonate (EC) and diethyl carbonate (DEC) (volume ratio EC:DEC = 1:1), where the LiPF6 concentration was 1 mol / L.

[0208] The battery was tested for charge and discharge using the LAND battery testing system.

[0209] (2) Cyclic gram capacity and first efficiency test: After the CR2032 battery is uncharged and left to stand for 6 hours, it is discharged at 0.1C to 0.005V, and the capacity is recorded as Q1; then it is discharged at a constant voltage of 0.005V until the current reaches 0.01C and then cut off; after standing for 5 minutes, it is charged at a constant current of 0.1C to 1.5V; the first delithiation gram capacity is the gram capacity (or mass specific capacity) of the electrode material, and the ratio of the first delithiation capacity to the first lithium insertion capacity is the first coulombic efficiency of the battery.

[0210] (3) Capacity retention test: After standing for 5 minutes, repeat the above charge and discharge steps twice; select 3 button batteries and discharge them to 0.05V at 0.1C. After standing for 2 hours, disassemble and measure the thickness of the negative electrode in turn, and record the average value as h1. Then discharge the remaining 3 button batteries to 0.005V at 0.25C; after standing for 5 minutes, charge them to 1.5V at 0.25C constant current, and cycle 50 times. The gram capacity retention rate is calculated by dividing the charge capacity of the 50th cycle by the charge capacity of the 1st cycle × 100%, and disassemble to obtain the average expansion thickness after 50 cycles as h2. The full charge expansion ratio = (h2-h1) / h1×100%.

[0211] The test results are shown in Table 1.

[0212] Table 1

[0213]

[0214] It can be seen from Table 1 that when the data of the mesoporous carbon matrix are not much different, the rate performance of the material becomes better with the increase of the amount of electrolyte added, and Example 5 is the optimal data; when the carbon source is within a certain phenol / aldehyde ratio range (0.6-1.3), a suitable carbon source can be obtained to meet the self-assembly of the template agent and form an ordered mesoporous channel; when the template agent exceeds the appropriate ratio, what is obtained is basically a non-porous solid carbon material, and it is meaningless to discuss the rate and first effect of silicon carbon at this time.

[0215] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A silicon-carbon negative electrode material with high ionic conductivity, characterized in that: include: Ordered mesoporous carbon matrices, silicon materials, and solid electrolyte materials; The silicon material is uniformly distributed in the mesopores of the ordered mesoporous carbon matrix; The solid electrolyte material is arranged on the surface of the ordered mesoporous carbon matrix or doped inside the ordered mesoporous carbon matrix.

2. The silicon-carbon negative electrode material with high ionic conductivity according to claim 1, characterized in that: The pore volume of the ordered mesoporous carbon matrix is ​​0.01 to 2 cm 3 / g, more preferably 0.6 to 1.1 cm 3 / g; The median particle size of the ordered mesoporous carbon matrix is ​​5 to 20 μm, more preferably 6 to 12 μm; The diameter pitch of the ordered mesoporous carbon matrix is ​​0.8 to 2.0, and more preferably 0.8 to 1.

2.

3. The silicon-carbon negative electrode material with high ionic conductivity according to claim 1, characterized in that: The ordered mesoporous carbon matrix has pore channels and pore wall stripes.

4. The silicon-carbon negative electrode material with high ionic conductivity according to claim 1, characterized in that: The silicon content of the silicon-carbon negative electrode material is 5 to 90%, more preferably 30 to 60%; The specific surface area of ​​the silicon-carbon negative electrode material is 0.1 to 50 m 2 / g, more preferably 0.5 to 10 m 2 / g; The pore volume of the silicon-carbon negative electrode material is 0.001 to 0.1 cm 3 / g, more preferably 0.001 to 0.05 cm 3 / g; The true density of the silicon-carbon negative electrode material measured by helium specific gravity is 1.3-2.0 g / cm 3 , the closed pore volume is 0.01~0.25cm 3 / g; The median particle size of the silicon-carbon negative electrode material is 5 to 20 μm, more preferably 6 to 12 μm; The diameter pitch of the silicon-carbon negative electrode material is 0.8 to 2.0, more preferably 0.8 to 1.

2.

5. The method for preparing a silicon-carbon negative electrode material with high ionic conductivity according to any one of claims 1 to 4, wherein: The following steps are involved: A mixture of a carbon source and a template agent is used as a precursor agent, and the precursor agent is sequentially subjected to optional balling treatment, curing treatment, carbonization treatment, and activation treatment to obtain an ordered mesoporous carbon matrix. Silicon is then deposited on the ordered mesoporous carbon matrix by vapor deposition to obtain a silicon-carbon negative electrode material with high ionic conductivity; The solid electrolyte material is added to the mixed solution of the carbon source and the template agent, or the solid electrolyte material is applied in a process after the activation treatment.

6. The preparation method according to claim 5, characterized in that The carbon source includes phenolic resin; Preferably, the carbon source preparation step comprises: dispersing an aldehyde material, a phenolic material, and a catalyst in water to obtain a phenolic resin mixture; Preferably, the preparation temperature of the carbon source is 40-100°C; Preferably, the aldehyde material includes one or more of formaldehyde, acetaldehyde and furfural; Preferably, the phenolic material comprises one or more of phenol and resorcinol; Preferably, the mass of the aldehyde material accounts for 60%-130% of the mass of the phenolic material; Preferably, the catalyst comprises one or more of an acidic catalyst and a basic catalyst; Preferably, the mass of the catalyst accounts for 1%-5% of the mass of the phenols; Preferably, the acidic catalyst comprises one or more of hydrochloric acid, sulfuric acid and oxalic acid; Preferably, the alkaline catalyst includes one or more of sodium hydroxide, calcium hydroxide and ammonia water.

7. The preparation method according to claim 5, characterized in that The steps of preparing the precursor agent include: mixing a template agent, a carbon source, a solvent and a solid electrolyte material to obtain a precursor agent; Preferably, the mass ratio of the carbon source, the template agent and the solvent is 1:0.5-2.0:0.1-4.0; Preferably, the preparation temperature of the precursor agent is 30-70°C, and the stirring time is 0.5-24h; Preferably, the template agent is obtained by polycondensation of polyoxyethylene, polyoxypropylene and polystyrene; Preferably, the template agent includes one or more of PEO-PPO-PEO, PPO-PEO-PPO and PEO-PS-PEO; Preferably, the molecular weight of the template agent is 1500-40000; Preferably, the PEO-PPO-PEO template agent includes one or more of F127, F188 and P123; Preferably, the solvent comprises one or more of dimethyl sulfoxide, tetrahydrofuran, ethanol and methanol.

8. The preparation method according to claim 7, characterized in that The addition amount of the solid electrolyte material is 0.5%-20% of the mass of the phenolic resin, preferably 1%-10%; Preferably, the solid electrolyte material includes one or more of an oxide solid electrolyte, a sulfide solid electrolyte, a polymer solid electrolyte, a composite solid electrolyte and a halide solid electrolyte; Preferably, the oxide solid electrolyte comprises one or more of lithium lanthanum zirconium oxide, lithium aluminum titanium phosphate and lithium superion conductor; Preferably, the sulfide solid electrolyte includes one or more of lithium phosphorus sulfur, lithium germanium phosphorus sulfur and lithium phosphorus sulfur chlorine; Preferably, the polymer solid electrolyte comprises one or more of polyethylene oxide, polyvinylidene fluoride and polyacrylonitrile; Preferably, the composite solid electrolyte includes one or both of a PEO-LLZO composite electrolyte and a PVDF-LGPS composite electrolyte; Preferably, the halide solid electrolyte includes one or both of Li3YCl6 and Li2ZrCl6.

9. The preparation method according to claim 5, characterized in that The spheroidization process adopts oil phase emulsion polymerization method; Preferably, the pelletizing step comprises: mixing a precursor agent, silicone oil and heat transfer oil and then separating them to obtain solid particles; Preferably, the mass ratio of the precursor agent, silicone oil and thermal oil is 1:1-5:1-10; Preferably, the silicone oil includes one or both of dimethyl silicone oil and phenyl silicone oil; Preferably, the viscosity of the silicone oil is 10-1000 cst, more preferably 100-600 cst; Preferably, the heat transfer oil comprises one or both of aromatic heat transfer oil and silicone heat transfer oil; Preferably, the viscosity of the heat transfer oil is 20-100 cst, more preferably 20-60 cst; Preferably, the curing temperature is 80-200°C and the curing time is 3-24h; Preferably, the temperature of the carbonization treatment is 500-1000°C, and the time of the carbonization treatment is 0.5-100h; Preferably, the temperature of the activation treatment is 500-1000°C, and the time of the activation treatment is 0.5-50h; Preferably, the medium used in the activation treatment includes one or more of CO2, water and O2; Preferably, when the solid electrolyte material is added after the activation treatment, the method further includes a sintering treatment after the solid electrolyte material is added; Preferably, the sintering temperature is 500-1100°C.

10. Use of the silicon-carbon negative electrode material with high ionic conductivity according to any one of claims 1 to 4 or the silicon-carbon negative electrode material with high ionic conductivity prepared by the preparation method of the silicon-carbon negative electrode material with high ionic conductivity according to any one of claims 5 to 9 in preparing a battery negative electrode.

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