Solid-state electrolyte doped silicon-carbon composite material, preparation method and application thereof

Abstract

The application discloses a kind of solid electrolyte doped silicon-carbon composite material and preparation method thereof.The preparation method is: phenolic substance, aldehyde substance, lithium titanium aluminum phosphorus mixture, dispersing agent and inorganic pore former are mixed uniformly, and through phenolic aldehyde reaction, solidification, carbonization and activation pore forming, prepare solid electrolyte doped porous carbon material;Afterwards, the obtained material is transferred to fluidized bed, and silane mixed gas is passed to deposit nano-silicon, passivation, then atomize catalyst on its surface, finally pass into carbon source gas, deposit carbon nanotube on its surface, obtain carbon nanotube coated solid electrolyte doped silicon-carbon composite material.The obtained material is applied to lithium ion battery, with good power performance, low expansion and excellent cycle performance and other characteristics.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion battery material preparation, specifically a solid electrolyte-doped silicon-carbon composite material and its preparation method. Background Technology

[0002] Porous carbon, due to its porous structure, high specific surface area, and low ionic conductivity, suffers from drawbacks such as low initial efficiency and low specific capacity when used as an anode material. Therefore, it needs to be combined with nano-silicon to leverage their respective advantages and improve the specific capacity and initial efficiency. However, poor power performance and low initial efficiency still exist. Although some researchers have improved the electronic conductivity of materials by doping with heteroatom compounds, the ionic conductivity has not been improved, limiting the improvement in power performance. Solid-state electrolytes, with their stable structure, high ionic conductivity, and good cycle performance, are used as novel materials in fields such as secondary batteries. However, there are few reports on preparing silicon-carbon materials by doping porous carbon with solid-state electrolytes and using it as a substrate for depositing nano-silicon, thereby improving the ionic conductivity and thus the power performance of silicon-carbon materials. Summary of the Invention

[0003] The present invention aims to at least partially solve one of the technical problems in the related art.

[0004] To improve the power performance of silicon-carbon, this invention first prepares a solid electrolyte-doped porous carbon material, and then performs nano-silicon deposition, catalyst deposition, and carbonization to prepare a carbon nanotube network-coated solid electrolyte-doped silicon-carbon composite material.

[0005] The purpose of this invention is to propose a solid electrolyte-doped silicon-carbon composite material, characterized in that: the composite material exhibits a core-shell structure, with the core being a solid electrolyte-doped silicon-carbon material and the outer shell being a carbon nanotube network;

[0006] The present invention also aims to provide a method for preparing a solid electrolyte-doped silicon-carbon composite material, characterized by comprising the following steps:

[0007] Step S1: Prepare solid electrolyte-doped porous carbon materials;

[0008] Phenolic substances, aldehydes, lithium-titanium-aluminum-phosphorus mixtures, dispersants, and inorganic pore-forming agents are added to an alkaline ammonia solution and mixed thoroughly in a mass ratio of 100:100-200:10-30:1-5:5-20. After the phenol-aldehyde reaction, the mixture is filtered, and the filter residue is solidified and then heated. Carbon dioxide or steam is introduced to activate the pore-forming process, resulting in a solid electrolyte-doped porous carbon material. The mass ratio of lithium source, titanium source, aluminum source, and phosphorus source in the lithium-titanium-aluminum-phosphorus mixture is 100:20-50:20-50:10-30.

[0009] Step S2: Prepare carbon nanotube network-coated composite material;

[0010] The above porous carbon material was placed in a fluidized bed, and after inert gas was introduced to purge air, it was heated and a silane mixed gas was introduced to deposit nano-silicon. After heating, a mixture of acetylene and argon gas was introduced for passivation to obtain an intermediate material. The intermediate was transferred to an atomization device, and the atomized catalyst solution was adsorbed at a temperature of 200-300℃. After drying, it was heated and carbon source gas was introduced for deposition to obtain a carbon nanotube network-coated solid electrolyte-doped silicon-carbon composite material.

[0011] The more specific process steps are as follows:

[0012] Step S1:

[0013] Phenolic substances, aldehydes, lithium sources, titanium sources, aluminum sources, phosphorus sources, dispersants, and inorganic pore-forming agents are added to an alkaline ammonia solution according to the mass ratio and mixed evenly. The ratio of phenolic substances: aldehydes: lithium source + titanium source + aluminum source + phosphorus source: dispersant: inorganic pore-forming agent is 100: 100-200: 10-30: 1-5: 5-20.

[0014] The solid electrolyte-doped porous carbon material was prepared by reacting phenolic resin at 50-100℃ for 2-6 hours, filtering, and solidifying the filter residue at 500-700℃ for 1-6 hours. Then, the temperature was raised to 1000-1300℃, and carbon dioxide gas or water vapor was introduced to activate and create pores at a flow rate of 100-500 mL / min for 60-600 min.

[0015] The mass ratio of lithium source: titanium source: aluminum source: phosphorus source is 100:20-50:20-50:10-30;

[0016] Step S2:

[0017] Solid electrolyte-doped porous carbon material is transferred to a fluidized bed, inert gas is introduced to purge air from the tube, and the temperature is raised to 450-550℃. A silane mixed gas is then introduced to deposit nano-silicon at a flow rate of 100-500 mL / min for 60-600 min. The temperature is then raised to 600-700℃, and an acetylene and argon mixed gas is introduced for passivation to obtain an intermediate material, where the volume ratio of acetylene to argon is 1-5:10. The intermediate material is then transferred to an atomizing device, and a catalyst solution is prepared. The catalyst solution is adsorbed onto the intermediate material under a vacuum of 0.1-0.5 Pa (absolute pressure) and a temperature of 200-300℃. The material is then vacuum dried, and the resulting material is heated to 500-800℃, and a carbon source gas is introduced at a flow rate of 100-500 mL / min for 60-600 min to obtain a carbon nanotube network-coated solid electrolyte-doped silicon-carbon composite material.

[0018] Further, in step S1, the phenolic compound is one of resorcinol, phenol, cresol, arylalkylphenol, cashew phenol, octylphenol, bisphenol A, or xylenol; and the aldehyde compound is one of formaldehyde, acetaldehyde, or furfural.

[0019] Further, in step S1, the lithium source is one of lithium carbonate, lithium hydroxide, lithium nitrate, and lithium chloride; the titanium source is one of titanium oxide, titanium hydroxide, titanium chloride, and orthotitanic acid; the aluminum source is one of aluminum oxide, aluminum hydroxide, and aluminum nitrate; and the phosphorus source is lithium phosphate or lithium dihydrogen phosphate.

[0020] Furthermore, in step S1, the dispersant is one of polyvinylpyrrolidone (PVP), polyacrylamide (PAM), and polyethylene glycol (PEG); the pore-forming agent is one of zinc chloride, zinc nitrate, and zinc bromide.

[0021] Further, in step S2, the silane mixed gas is a mixture of one of silane, silane, dichlorosilane, and trichlorosilane with argon, in a volume ratio of 1-5:10.

[0022] The present invention also aims to propose a solid electrolyte-doped silicon-carbon composite material for use in lithium-ion batteries.

[0023] In step S1 of this application, a LATP solid electrolyte (lithium aluminum titanium phosphate) is formed in porous carbon by using lithium, titanium, aluminum and phosphorus sources in a specific ratio. The solid electrolyte network significantly improves the ionic conductivity, filling the gap in the existing technology that relies solely on elemental doping to improve electron transport capability, thereby improving the diffusion coefficient, ionic conductivity and structural stability of the material.

[0024] In step S2 of this application, a catalyst solution, such as ferric chloride or cobalt chloride, is deposited on the surface of an intermediate under vacuum conditions using an atomization device to induce the growth of carbon nanotubes. Catalyst atomization enables the directional growth of the carbon coating layer to form a carbon nanotube network. Compared with the amorphous carbon coating in the prior art, the electronic conductivity is significantly improved, while the volume expansion of silicon is buffered more effectively.

[0025] This application utilizes inorganic pore-forming agents (zinc chloride, zinc nitrate, etc.) in synergistic activation with carbon dioxide or water vapor to create pores, resulting in a more uniform pore size distribution. The controllable porous structure significantly increases the amount of silicon deposited, achieving an initial discharge specific capacity of 1982.7 mAh / g, and the silicon particles are more evenly distributed, reducing structural damage caused by agglomeration.

[0026] Beneficial effects:

[0027] 1. A LATP solid electrolyte is prepared by reacting lithium source, titanium source, aluminum source and phosphorus source in a certain mass ratio. It is then mixed with a phenolic resin precursor to improve the ionic conductivity of the material. Inorganic pore-forming agent is doped and carbonized to obtain a solid electrolyte doped with porous carbon, which has the characteristics of high porosity and high ionic conductivity. This increases the amount of silicon deposited in the material and improves the specific capacity of the silicon-carbon anode material.

[0028] 2. Solid electrolyte-doped porous carbon materials are deposited with nano-silicon via silane pyrolysis and passivated with an acetylene mixed gas to obtain silicon-carbon materials. This improves specific capacity and reduces side reactions through surface passivation, thereby enhancing initial efficiency and storage performance. Simultaneously, a catalyst is deposited via atomization and used as a substrate to grow carbon nanotubes, resulting in a carbon nanotube network-coated solid electrolyte-doped silicon-carbon composite material. By leveraging the high electronic conductivity of the outer carbon nanotube network and the ionic conductivity of the core solid electrolyte, and by utilizing the synergistic effect between the two, the power performance of the material is improved. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 The image shows a SEM image of the carbon nanotube network-coated solid electrolyte-doped silicon-carbon composite material prepared in Example 1. Detailed Implementation

[0031] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0032] With regard to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0033] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0034] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be obvious to those skilled in the art. This specification and embodiments are merely exemplary.

[0035] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0036] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0037] Example 1

[0038] A solid electrolyte-doped silicon-carbon composite material and its preparation method include the following steps:

[0039] Step S1:

[0040] 100g resorcinol, 150g formaldehyde, 10g lithium carbonate, 4g titanium dioxide, 4g aluminum oxide, 2g lithium phosphate, 3g polyvinylpyrrolidone, and 10g zinc chloride were added to 1000g ammonia alkaline solution and mixed evenly. The mixture was then subjected to a phenol-formaldehyde reaction at 80℃ for 4 hours. After filtration, the resulting filter residue was solidified at 600℃ for 3 hours. Subsequently, the temperature was raised to 1200℃, and steam was introduced at a flow rate of 300mL / min for 300 minutes to activate and create pores, thus preparing a solid electrolyte-doped porous carbon material.

[0041] Step S2:

[0042] Solid electrolyte-doped porous carbon material was transferred to a fluidized bed, and argon inert gas was introduced to purge the air inside the tube. The bed was heated to 500°C, and a silane-silane mixed gas (volume ratio: silane:argon = 3:10) was introduced at a flow rate of 300 mL / min for 300 min to deposit nano-silicon. Then, the temperature was raised to 650°C, and an acetylene-acetylene mixed gas (volume ratio: acetylene:argon = 3:10) was introduced for passivation to obtain an intermediate material. 100 g of the intermediate material was then transferred to an atomization device, and 500 g of ferric chloride solution was prepared as a catalyst with a concentration of 0.6 wt%. The catalyst solution was atomized and deposited on the surface of the intermediate material under a vacuum of 0.3 Pa and a temperature of 250°C. The material was then vacuum dried at 80°C for 24 h. The resulting material was then heated to 650°C, and ethylene carbon source gas was introduced at a flow rate of 300 mL / min for 300 min to obtain a carbon nanotube network-coated solid electrolyte-doped silicon-carbon composite material.

[0043] Example 2

[0044] A solid electrolyte-doped silicon-carbon composite material and its preparation method include the following steps:

[0045] Step S1:

[0046] 100g phenol, 100g acetaldehyde, 5g lithium hydroxide, 2g titanium hydroxide, 2g aluminum hydroxide, 1g lithium phosphate, 1g polyacrylamide, and 5g zinc nitrate were added to 1000g ammonia alkaline solution and mixed evenly. The mixture was then subjected to a phenol-aldehyde reaction at 50℃ for 6 hours. After filtration, the resulting filter residue was solidified at 500℃ for 6 hours. Subsequently, the temperature was raised to 1000℃, and steam was introduced at a flow rate of 100mL / min for 600 minutes to activate and create pores, thus preparing a solid electrolyte-doped porous carbon material.

[0047] Step S2:

[0048] Solid electrolyte-doped porous carbon material was transferred to a fluidized bed, and argon inert gas was introduced to purge the air inside the tube. The bed was heated to 450°C, and a silane-silane mixed gas (volume ratio, silane:argon = 1:10) was introduced at a flow rate of 100 mL / min for 600 min to deposit nano-silicon. Then, the temperature was raised to 600°C, and an acetylene-acetylene mixed gas (volume ratio, acetylene:argon = 1:10) was introduced for passivation to obtain an intermediate material. 100 g of the intermediate material was then transferred to an atomization device, and 500 g of cobalt chloride solution with a concentration of 0.2 wt% was prepared as a catalyst. The catalyst solution was atomized and deposited on the surface of the intermediate material under a vacuum of 0.1 Pa and a temperature of 200°C. The resulting material was vacuum dried at 80°C for 24 h. The resulting material was then heated to 500°C, and acetylene gas was introduced at a flow rate of 100 mL / min for 600 min to obtain a carbon nanotube network-coated solid electrolyte-doped silicon-carbon composite material.

[0049] Example 3

[0050] A solid electrolyte-doped silicon-carbon composite material and its preparation method include the following steps:

[0051] Step S1:

[0052] 100g cresol, 200g furfural, 12.5g lithium nitrate, 5g titanium chloride, 5g aluminum nitrate, 2.5g lithium phosphate, 2g polyethylene glycol, and 5g zinc bromide were added to 1000g ammonia water alkaline solution and mixed evenly. The mixture was then subjected to a phenol-formaldehyde reaction at 100℃ for 2 hours. After filtration, the resulting filter residue was solidified at 700℃ for 1 hour. Subsequently, the temperature was raised to 1300℃, and steam was introduced at a flow rate of 500mL / min for 60 minutes to activate and create pores, thus preparing a solid electrolyte-doped porous carbon material.

[0053] Step S2:

[0054] Solid electrolyte-doped porous carbon material was transferred to a fluidized bed, and argon inert gas was introduced to purge the air inside the tube. The bed was heated to 550°C, and a dichlorosilane mixed gas (volume ratio: dichlorosilane: argon = 5:10) was introduced at a flow rate of 500 mL / min for 60 min to deposit nano-silicon. Then, the temperature was raised to 700°C, and an acetylene mixed gas (volume ratio: acetylene: argon = 5:10) was introduced for passivation to obtain an intermediate material. 100 g of the intermediate material was then transferred to an atomization device. 500 g of nickel chloride solution was prepared as a catalyst with a concentration of 1 wt%. The catalyst solution was atomized and deposited on the surface of the intermediate material under a vacuum of 0.5 Pa and a temperature of 300°C. The resulting material was vacuum dried at 80°C for 24 h. The resulting material was then heated to 800°C, and methane gas was introduced at a flow rate of 500 mL / min for 60 min to obtain a carbon nanotube network-coated solid electrolyte-doped silicon-carbon composite material.

[0055] Comparative Example 1:

[0056] Unlike Example 1, lithium carbonate, titanium oxide, aluminum oxide, and lithium phosphate are not added in step S1; otherwise, they are the same as in Example 1.

[0057] Comparative Example 2:

[0058] Unlike Example 1, step S2 does not involve adding ferric chloride solution or using atomization to deposit ferric chloride catalyst on the surface of the intermediate; otherwise, it is the same as Example 1.

[0059] Test case

[0060] 1. Appearance

[0061] SEM tests were performed on the solid electrolyte-doped silicon-carbon composite material in Example 1, and the test results are as follows: Figure 1 As shown. By Figure 1 It can be seen that the material has a porous structure and the material particles adsorb a small amount of fine powder, with a particle size between 5-10 μm.

[0062] 2. Button cell battery test

[0063] The solid electrolyte-doped silicon-carbon composite materials from Examples 1-3 and Comparative Examples 1-2 were used as negative electrode materials for lithium-ion batteries to prepare coin cells. The preparation method is as follows:

[0064] A binder, conductive agent, and solvent were added to the composite material, stirred to form a slurry, coated onto copper foil, and then dried and rolled to obtain the negative electrode sheet. The binder used was polyvinylidene fluoride (PVDF), the conductive agent was conductive carbon black (SP), and the solvent was N-methylpyrrolidone (NMP). The ratio of composite material, SP, PVDF, and NMP was 90g:4g:6g:250mL. The electrolyte used lithium hexafluorophosphate (LiPF6) as the electrolyte and a mixture of ethylene carbonate (EC) and diethyl carbonate (DEC) in a 1:1 volume ratio as the solvent, with an electrolyte concentration of 1mol / L. A lithium metal sheet was used as the counter electrode, and a polypropylene (PP) membrane was used as the separator. The button cell was assembled in an argon-filled glove box.

[0065] Electrochemical performance tests were conducted on the coin cells containing silicon-carbon composite materials from Examples 1-3 and Comparative Examples 1-2. The tests were performed using a Wuhan Landian CT2001A battery tester, with a charge / discharge voltage range of 0.005V to 2.0V and a charge / discharge rate of 0.1C. The charge DCR (50% SOC) of the materials was also tested.

[0066] The thickness D1 of the negative electrode sheet of the coin cell containing the silicon-carbon composite materials of Examples 1-3 and Comparative Examples 1-2 after roll pressing was measured. Then, the full-charge thickness D2 of the negative electrode sheet was dissected after the coin cell was fully charged to 100% SOC, and the expansion rate was calculated.

[0067] Expansion rate = (D2 - D1) / D1 × 100%

[0068] The specific surface area and tap density of silicon-carbon composite materials were tested in accordance with GB / T38823-2020 "Silicon-Carbon", and the ionic conductivity of the materials was tested using an AC impedance meter.

[0069] The test results are shown in Table 1.

[0070] Table 1

[0071] Material First discharge specific capacity (mAh / g) First-time efficiency (%) <![CDATA[Specific surface area (m 2 / g)]]> <![CDATA[Tap density (g / cm 3 ).]]> <![CDATA[Ionic conductivity (S / cm, 10 -6 )]]> Fully charged expansion DCR (Ω) Example 1 1982.7 95.6 3.12 1.05 4.54 78.1% 87.5 Example 2 1933.5 95.2 2.98 1.03 1.21 82.2% 76.3 Example 3 2019.4 96.4 3.43 1.07 9.87 75.9% 98.5 Comparative Example 1 1860.3 91.2 2.34 0.96 0.54 104.3% 121.4 Comparative Example 2 1890.5 92.4 2.58 0.99 0.89 97.6% 103.2

[0072] As can be seen from the data in Table 1, the specific capacity, initial efficiency, ionic conductivity, full-charge expansion, and DCR of the silicon-carbon composite material prepared in this invention are significantly better than those of the comparative example. This is because doping the material with a solid electrolyte improves the ionic conductivity, and the outer carbon nanotube network enhances the electronic conductivity, reducing polarization and improving the specific capacity. Simultaneously, the outer carbon nanotube network confines the expansion of silicon during charging and discharging, reducing the full-charge expansion of the silicon-carbon composite material.

[0073] 3. Pouch Battery Testing

[0074] The silicon-carbon composite materials of Examples 1-3 and Comparative Examples 1-2 were blended with artificial graphite at a mass ratio of 5:95 as negative electrode materials, and ternary materials (LiNi) were used. 1 / 3 Co 1 / 3 Mn 1 / 3 A 5Ah pouch cell was fabricated using lithium hexafluorophosphate (LiPF6) as the positive electrode and a 1:1 mixture of ethylene carbonate (EC) and methyl ethyl carbonate (EMC) as the solvent in the electrolyte, with an electrolyte concentration of 1.3 mol / L. A Celgard 2400 membrane was used as the separator. The liquid absorption and retention capacity, gas generation, rate capability, and high-temperature cycling performance of the negative electrode were tested.

[0075] a. Liquid absorption capacity test

[0076] A 1 mL burette was used to draw 1 mL of electrolyte and add one drop to the surface of the electrode. The time was recorded until the electrolyte was completely absorbed. The test results are shown in Table 2.

[0077] b. Electrode gas generation test

[0078] The mass of the active material of the negative electrode sheet is calculated as m1, and it is placed in the electrolyte at 45°C and left to stand for 48 hours. Then the generated gas is collected and its gas production is calculated.

[0079] Table 2

[0080] Material Liquid aspiration rate (s) Gas production (mL / g) Example 1 121 0.07 Example 2 134 0.09 Example 3 108 0.05 Comparative Example 1 156 0.15 Comparative Example 2 141 0.11

[0081] As can be seen from Table 2, the liquid absorption capacity and electrode gas production of the silicon-carbon composite materials obtained in Examples 1-3 are significantly lower than those in the comparative examples. This may be because the composite materials in the examples have a higher specific surface area, enhancing their liquid absorption and retention capacity; simultaneously, the vapor deposition method encapsulates amorphous carbon and carbon nanotubes on the silicon-carbon material shell, improving the integrity of the encapsulation and reducing gas production.

[0082] c. Ratio and Cyclic Performance

[0083] Cycle performance and rate testing were performed on the pouch cells containing the silicon-carbon composite materials of Examples 1-3 and Comparative Examples 1-2.

[0084] Ratio test: The constant current ratio of the material under 1C conditions is tested. The constant current ratio = 1C constant current capacity / (1C constant current capacity + 0.1C constant voltage capacity). The test results are shown in Table 3.

[0085] Cyclic testing: charge / discharge rate 1C / 1C, voltage range 2.5-4.2V, temperature 25±3℃, cycle number 500 cycles.

[0086] Table 3

[0087] Lithium-ion batteries Cyclic performance 1C constant current ratio Example 1 94.6% 87.3% Example 2 94.1% 85.7% Example 3 94.9% 88.4% Comparative Example 1 91.2% 82.4% Comparative Example 2 92.4% 83.9%

[0088] As shown in Table 3, the soft-pack lithium-ion battery prepared using the silicon-carbon composite material of the present invention has better cycle performance and constant current ratio than the comparative example. This is because the silicon-carbon composite material of the present invention has excellent ionic conductivity to reduce impedance and carbon nanotube network coating on the outer layer to improve the electronic conductivity of the material, reduce expansion, and improve cycle performance and rate performance.

[0089] By comparing the test results of the embodiments and comparative examples, we can conclude that:

[0090] Solid-state electrolyte doping increases ionic conductivity by 8-18.2 times; catalyst atomization process reduces internal resistance by 20%-30%; Example 3 achieved the highest ionic conductivity (9.87×10⁻⁶) using a lithium nitrate + titanium chloride system. -6 (S / cm) to verify the effect of lithium source type on solid electrolyte performance. The porous structure and carbon coating layer synergistically improve liquid absorption and retention capacity; carbon nanotube network suppresses gas production, reducing gas production by 40%-67%; the "ion-electron" synergistic effect of solid electrolyte and carbon nanotubes improves cycle stability, with a cycle retention rate of over 94% after 500 cycles.

[0091] This application achieves precise control over the material structure through a three-step core process: solid-state electrolyte doping, fluidized bed silicon deposition, and catalyst atomization. The synergistic effect of the solid-state electrolyte and the carbon nanotube network enables the material to achieve a high ionic conductivity (up to 9.87 × 10⁻⁶). -6 In terms of S / cm, cycle life (94.9% retention after 500 cycles), and expansion inhibition (75.9%), it outperforms existing technologies. For the first time, LATP solid electrolyte is introduced into a porous carbon substrate to construct an "ion-electron" dual conductive network; the catalyst atomization process breaks through the uniformity bottleneck of traditional carbon coating, providing a new path for high-power silicon-carbon anodes.

[0092] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0093] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0094] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method of making a solid-state electrolyte doped silicon-carbon composite material, the method comprising: Includes the following steps: ​ Step S1: Prepare solid electrolyte-doped porous carbon material; Phenolic substances, aldehydes, a lithium-titanium-aluminum-phosphorus mixture, a dispersant, and an inorganic pore-forming agent are added to an alkaline ammonia solution and mixed thoroughly in a mass ratio of 100:100-200:10-30:1-5:5-20. After the phenol-aldehyde reaction, the mixture is filtered, and the filter residue is solidified and then heated. Carbon dioxide or water vapor is introduced to activate the pore-forming process, forming a LATP solid electrolyte, thus obtaining a solid electrolyte-doped porous carbon material. The mass ratio of lithium source, titanium source, aluminum source, and phosphorus source in the lithium-titanium-aluminum-phosphorus mixture is 100:20-50:20-50:10-30. Step S2: Prepare carbon nanotube network-coated composite material; The aforementioned porous carbon material was placed in a fluidized bed, inert gas was introduced to purge air, and then heated. A silane mixed gas was then introduced to deposit nano-silicon. After heating, a mixture of acetylene and argon gas was introduced for passivation, yielding an intermediate material. The intermediate was transferred to an atomization device, where an atomized catalyst solution was adsorbed at 200-300℃, followed by vacuum drying. The resulting material was then heated to 500-800℃ and deposited with a carbon source gas to obtain a carbon nanotube network-coated solid electrolyte-doped silicon-carbon composite material. An "ion-electron" dual-conductivity network was constructed. The ionic conductivity of the obtained composite material was 1.21 × 10⁻⁶. - 6 S / cm up to 9.87×10 -6 S / cm; The catalyst solution is one of ferric chloride, cobalt chloride, and nickel chloride.

2. The method for preparing a solid electrolyte-doped silicon-carbon composite material according to claim 1, characterized in that: In step S1, the phenolic substance is one of resorcinol, phenol, cresol, arylalkylphenol, cashew phenol, octylphenol, bisphenol A, or xylenol; the aldehyde substance is one of formaldehyde, acetaldehyde, or furfural.

3. The method for preparing a solid electrolyte-doped silicon-carbon composite material according to claim 1, characterized in that: In step S1, the lithium source is one of lithium carbonate, lithium hydroxide, lithium nitrate, and lithium chloride; the titanium source is one of titanium oxide, titanium hydroxide, titanium chloride, and orthotitanic acid; the aluminum source is one of aluminum oxide, aluminum hydroxide, and aluminum nitrate; and the phosphorus source is lithium phosphate or lithium dihydrogen phosphate.

4. The method for preparing a solid electrolyte-doped silicon-carbon composite material according to claim 1, characterized in that: In step S1, the dispersant is one of polyvinylpyrrolidone (PVP), polyacrylamide (PAM), or polyethylene glycol (PEG); the pore-forming agent is one of zinc chloride, zinc nitrate, or zinc bromide.

5. The method for preparing a solid electrolyte-doped silicon-carbon composite material according to claim 1, characterized in that: In step S2, the silane mixed gas is a mixture of one of the following: methylsilane, dichlorosilane, dichlorosilane, and trichlorosilane, with argon, in a volume ratio of 1-5:

10.

6. Use of a solid-state electrolyte doped silicon-carbon composite material according to any one of claims 1-5, characterized in that: Used in lithium-ion batteries.

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