Composite porous carbon matrix material coated with solid-state electrolyte in situ and preparation method thereof

Abstract

This invention relates to a composite porous carbon matrix material with in-situ coated solid electrolyte and its preparation method. The composite porous carbon matrix material includes a porous carbon matrix and a solid electrolyte layer in-situ coated on the surface and pore walls of the porous carbon matrix. The solid electrolyte layer has a continuous phase structure. The solid electrolyte in the solid electrolyte layer includes one or more of fluoride-based solid electrolytes, oxide-based solid electrolytes, and sulfide-based solid electrolytes. The solid electrolyte layer is formed by sequentially depositing a solid electrolyte precursor on the surface and pore walls of a surface-activated porous carbon matrix using atomic layer deposition (ALD) technology, followed by heat treatment to allow the precursor atoms to migrate, diffuse, and undergo phase transformation. The composite porous carbon matrix material of this invention has a high specific surface area, good ionic and electronic conductivity, and low interfacial resistance, and can be used as a novel porous carbon material in many fields, with wider applications.

Description

Technical Field

[0001] This invention relates to the field of porous carbon materials technology, and in particular to a composite porous carbon matrix material with in-situ coating of solid electrolyte and its preparation method. Background Technology

[0002] Porous carbon materials have abundant pore structures and high specific surface areas, and have wide applications in daily life and industrial production, such as: absorption of harmful gases, adsorption of pollutants, storage and separation of gases, matrix materials for battery materials, and electrode materials for supercapacitors.

[0003] Porous carbon materials are excellent electronic conductors, but their internal pores are generally not conducive to rapid ion transport. Furthermore, when porous carbon materials are used in batteries, unwanted side reactions may occur on their surface under battery operating conditions, especially when in contact with highly active electrode materials such as lithium metal, high-voltage cathodes, or sulfur cathodes. These side reactions include reduction decomposition, corrosion, and the formation of unstable interfacial layers. Current methods to address these issues involve coating the porous carbon material with a solid electrolyte layer. This can improve the ionic conductivity of the porous carbon material to some extent while preventing side reactions.

[0004] In existing technologies, when coating solid electrolytes onto the surface of porous carbon, the traditional solid-state method is often used, which involves blending the solid electrolyte with the porous carbon material. This method suffers from problems such as uneven powder mixing, particle accumulation, and uneven coating, leading to localized excess of elements, the formation of impurity phases, high interfacial impedance, blockage of ion channels, and a reduced specific surface area, thus affecting the quality of the finished product. Furthermore, the traditional solid-state method requires heat treatment at high temperatures for extended periods, resulting in high costs and reduced production efficiency. Summary of the Invention

[0005] The purpose of this invention is to address the deficiencies of existing technologies by providing a composite porous carbon matrix material for in-situ coating of solid electrolytes and its preparation method.

[0006] This invention utilizes atomic layer deposition (ALD) technology to deposit a solid electrolyte precursor, forming an ultrathin and uniform chemical bonding layer on the surface of a porous carbon matrix and the pore walls. During heat treatment, atoms only need to migrate a short distance to complete the crystal phase transformation, rather than the high-temperature-driven interparticle diffusion required in traditional solid-state methods. The resulting in-situ coated solid electrolyte composite porous carbon matrix material maintains a high specific surface area while also exhibiting good ionic and electronic conductivity and low interfacial resistance. Compared to the original porous carbon matrix, it possesses superior performance and can be used as a novel porous carbon material in many fields, with a wider range of applications.

[0007] To achieve the above objectives, in a first aspect, the present invention provides a composite porous carbon matrix material with in-situ solid electrolyte coating, the composite porous carbon matrix material comprising: a porous carbon matrix, and a solid electrolyte layer in-situ coating the surface and pore walls of the porous carbon matrix; The solid electrolyte layer has a continuous phase structure; the solid electrolyte in the solid electrolyte layer includes one or more of the following: fluoride oxide-based solid electrolyte, oxide-based solid electrolyte, and sulfide-based solid electrolyte. The solid electrolyte layer is formed by sequentially depositing the precursor of the solid electrolyte on the surface and pore walls of a porous carbon substrate that has undergone surface activation treatment using atomic layer deposition technology, and then subjecting the precursor to heat treatment to allow the atoms to migrate, diffuse, and undergo crystal phase transformation.

[0008] Preferably, the porous carbon matrix includes one or more of the following: porous resin carbon, porous biomass carbon, porous pitch coke, or porous petroleum coke. The porous carbon matrix has an average particle size Dv50 of 4 μm to 100 μm, a porosity of 50% to 85%, a pore size of 2 nm to 50 nm, and a specific surface area of ​​1000 m². 2 / g~3000m 2 / g, pore volume 0.5cm 3 / g~3cm 3 / g.

[0009] Preferably, the thickness of the solid electrolyte layer is between 1 nm and 25 nm; The fluoride-based solid electrolyte includes: Li 1.5 Al 0.5 Ge 1.5 (PO4) 2.9 F 0.1 Li 6.5 La3Zr 1.5 Ta 0.5 O 11.5 F 0.5 Li₂VO₂F, Li 1.2 Mn 0.8 Nb 0.2 O 1.6 F 0.4 Li m La n A a B b C cOne or more of O6F; wherein, 1 < m + 3n < 5, 0 < m ≤ 2, 1 / 3 < n < 5 / 3; 0 ≤ a ≤ 2, 0 ≤ b ≤ 2, 0 ≤ c ≤ 2, a + b + c = 2; A is one or more of Zr, Ti, Hf, Si, Ge, Sn; B is one or more of Nb, Sb, Bi, V, Ta; C is one or more of W, Cr, Mo, Mn; The oxide-based solid electrolyte includes: garnet-type oxide solid electrolyte Li7Al3B12O 12 Perovskite oxide solid electrolyte Li 3x A2 2 / 3-x B2O3, NASICON-type oxide solid electrolyte Li 1+y A3 y B3 2-y One or more of (PO4)3, wherein 0.01≤x≤0.5, 0.01≤y≤0.5; A1 is one or more of La, Ca, Sr, Ba, K, and B1 is one or more of Zr, Ta, Nb, Hf; A2 is one or more of La, Al, Mg, Fe, Ta, and B2 is one or more of Ti, Nb, Sr, Pr; A3 is one or more of Al, Y, Ga, Cr, In, Fe, Se, La, and B3 is one or more of Ti, Ge, Ta, Zr, Sn, Fe, V, Hf. The sulfide-based solid electrolytes include: argillium sulfide-germanium ore type solid electrolyte Li6PS5N1, and LGPS type sulfide solid electrolyte Li... 11-z M1 2-z P 1+z S 12 Thio-LISICON type sulfide solid electrolytes (100-u)Li₂S-uP₂S₅, (100-u)Li₂S-uSiS₂, Li 4-v Ge 1-v P v S4 includes one or more of the following elements: 0 < z < 2, 0 < u < 100, 0 < v < 1; N1 includes any one of Cl, Br, and I elements; M1 includes any one of Ge, Si, and Sn elements.

[0010] In a second aspect, the present invention provides a method for preparing a composite porous carbon matrix material with in-situ coating of solid electrolyte as described in the first aspect above, the preparation method comprising: The preparation of an activated porous carbon matrix includes: performing a surface activation treatment on the porous carbon matrix to make the surface of the porous carbon matrix contain -OH bonds, thereby obtaining an activated porous carbon matrix; A composite porous carbon precursor is obtained by depositing the elements required to form a solid electrolyte on the surface and pore walls of an activated porous carbon matrix using atomic layer deposition technology. The process includes: placing the activated porous carbon matrix in a fluidized bed powder atomic layer deposition apparatus, heating it to 150℃~350℃, sequentially introducing a precursor of a solid electrolyte, purging with an inert gas after each introduction of a precursor containing one or more elements, and intermittently introducing an oxidizing gas source to react, so that different elements in the precursor are deposited on the surface of the porous carbon matrix, and repeating the above deposition process 100 to 300 times to obtain the composite porous carbon precursor. The composite porous carbon precursor is heat-treated to allow different elements to undergo atomic diffusion and crystal phase transformation to form a solid electrolyte layer, thus obtaining a composite porous carbon matrix material with in-situ solid electrolyte coating.

[0011] Preferably, the porous carbon matrix includes one or more of the following: porous resin carbon, porous biomass carbon, porous pitch coke, or porous petroleum coke. The porous carbon matrix has an average particle size Dv50 of 4 μm to 100 μm, a porosity of 50% to 85%, a pore size of 2 nm to 50 nm, and a specific surface area of ​​1000 m². 2 / g~3000m 2 / g, pore volume 0.5cm 3 / g~3cm 3 / g.

[0012] Preferably, the surface activation treatment is an acid activation treatment or an alkaline activation treatment; The acid activation treatment includes: immersing a porous carbon matrix in an acidic solution, stirring at 60℃~120℃ for 1 hour~10 hours, washing with deionized water until neutral after the reaction, and drying at a low temperature of 60℃~80℃ to obtain an activated porous carbon matrix with -OH bonds on its surface; the mass ratio of the porous carbon matrix to the acidic solution is 10%~50%; the acidic solution includes a nitric acid solution with a concentration of 20wt%-70wt% and / or hydrogen peroxide; The alkaline activation treatment includes: placing a porous carbon matrix and potassium hydroxide powder in a ball mill at a ratio of 1-5:5-9, and ball milling at 500-1000 rpm for 2-8 hours under an inert atmosphere. Zirconia balls are used as the milling media. After ball milling, residual potassium ions are removed by washing with dilute hydrochloric acid with a molar concentration of 0.1 mol / L-1 M / L. After drying at 60℃-100℃, an activated porous carbon matrix with -OH bonds on its surface is obtained.

[0013] Preferably, the volumetric flow rate of the gas precursor of the solid electrolyte is 50 sccm to 500 sccm; The solid electrolyte in the solid electrolyte layer includes one or more of the following: fluoride-based solid electrolyte, oxide-based solid electrolyte, and sulfide-based solid electrolyte.

[0014] More preferably, the fluoride-based solid electrolyte comprises: Li 1.5 Al 0.5 Ge 1.5 (PO4) 2.9 F 0.1 Li 6.5 La3Zr 1.5 Ta 0.5 O 11.5 F 0.5 Li₂VO₂F, Li 1.2 Mn 0.8 Nb 0.2 O 1.6 F 0.4 Li m La n A a B b C c One or more of O6F; wherein, 1 < m + 3n < 5, 0 < m ≤ 2, 1 / 3 < n < 5 / 3; 0 ≤ a ≤ 2, 0 ≤ b ≤ 2, 0 ≤ c ≤ 2, a + b + c = 2; A is one or more of Zr, Ti, Hf, Si, Ge, Sn; B is one or more of Nb, Sb, Bi, V, Ta; C is one or more of W, Cr, Mo, Mn; The oxide-based solid electrolyte includes: garnet-type oxide solid electrolyte Li7Al3B12O 12 Perovskite oxide solid electrolyte Li 3x A2 2 / 3-x B2O3, NASICON-type oxide solid electrolyte Li 1+y A3 y B3 2-y One or more of (PO4)3, wherein 0.01≤x≤0.5, 0.01≤y≤0.5; A1 is one or more of La, Ca, Sr, Ba, K, and B1 is one or more of Zr, Ta, Nb, Hf; A2 is one or more of La, Al, Mg, Fe, Ta, and B2 is one or more of Ti, Nb, Sr, Pr; A3 is one or more of Al, Y, Ga, Cr, In, Fe, Se, La, and B3 is one or more of Ti, Ge, Ta, Zr, Sn, Fe, V, Hf. The sulfide-based solid electrolytes include: argillium sulfide-germanium ore type solid electrolyte Li6PS5N1, and LGPS type sulfide solid electrolyte Li... 11-z M12-z P 1+z S 12 Thio-LISICON type sulfide solid electrolytes (100-u)Li₂S-uP₂S₅, (100-u)Li₂S-uSiS₂, Li 4-v Ge 1-v P v S4 includes one or more of the following elements: 0 < z < 2, 0 < u < 100, 0 < v < 1; N1 includes any one of Cl, Br, and I elements; M1 includes any one of Ge, Si, and Sn elements.

[0015] Preferably, the oxidizing gas source includes O3 and / or H2O; the volumetric flow rate of the oxidizing gas source is 50 sccm to 500 sccm; The inert gas includes one or more of nitrogen, helium, or argon; the volumetric flow rate of the inert gas is 100 sccm to 1000 sccm.

[0016] Preferably, the heat treatment specifically includes: placing the composite porous carbon precursor in a high-temperature device, heating it to 300℃~900℃ at a heating rate of 2℃ / min~5℃ / min, and holding it at that temperature for 2 hours~8 hours, so that different elements on the surface of the composite porous carbon precursor undergo atomic diffusion and crystal phase transformation to form a solid electrolyte layer, thereby obtaining a composite porous carbon matrix material with in-situ coated solid electrolyte.

[0017] This invention provides a composite porous carbon matrix material for in-situ coating of solid electrolytes and its preparation method, which has the following technical advantages: (1) This invention provides a method for in-situ coating of a solid electrolyte onto a composite porous carbon matrix. First, the porous carbon matrix is ​​surface-activated to obtain an activated porous carbon matrix containing -OH bonds. Then, a precursor of a solid electrolyte is sequentially deposited on the surface and pore walls of the activated porous carbon matrix using atomic layer deposition (ALD) technology. An oxidizing gas source is intermittently introduced to allow the precursor of the solid electrolyte to react and bond with the -OH bonds on the surface of the porous carbon matrix. This deposition process is repeated. Finally, heat treatment allows different elements to undergo atomic diffusion and phase transformation to form a solid electrolyte layer, resulting in an in-situ coated composite porous carbon matrix material with a solid electrolyte. This invention achieves atomic-level precise coating on the surface and pore walls of the porous carbon matrix through an "activation treatment-fluidized bed ALD-heat treatment" process, solving the problem of uneven element deposition and avoiding the problem of localized element excess caused by uneven powder mixing in traditional solid-phase methods, thus reducing the generation of impurity phases at the source.

[0018] (2) The composite porous carbon matrix material with in-situ coating of solid electrolyte obtained by the preparation method provided by the present invention uses a porous carbon matrix with high specific surface area to construct a continuous three-dimensional substrate. The retention of ALD technology ensures that the precursor of solid electrolyte can be uniformly covered at the atomic layer level on the inner and outer surfaces of the porous carbon matrix. After cyclic deposition and heat treatment, the elements in the precursor grow continuously along the pore network of the porous carbon matrix, and finally form a continuous phase structure that runs through the matrix. Unlike the discrete structure of particle stacking in the traditional solid phase coating method, it will not block the pores and has little impact on the pore structure of the porous carbon matrix. The specific surface area change rate is small (the specific surface area retention rate is above 90%).

[0019] (3) The composite porous carbon matrix material with in-situ coating of solid electrolyte provided by the present invention has good ionic conductivity and electronic conductivity, and small interfacial resistance while ensuring the high specific surface area of ​​the material. It has better performance than the original porous carbon matrix and can be used as a new type of porous carbon material in many fields, with a wider range of applications. Attached Figure Description

[0020] Figure 1 This is a flowchart illustrating the preparation method of a composite porous carbon matrix material with in-situ coating of solid electrolyte provided in an embodiment of the present invention. Detailed Implementation

[0021] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0023] This invention provides a composite porous carbon matrix material with in-situ solid electrolyte coating, comprising: a porous carbon matrix, and a solid electrolyte layer in-situ coated on the surface and pore walls of the porous carbon matrix.

[0024] The porous carbon matrix includes one or more of the following: porous resin carbon, porous biomass carbon, porous pitch coke, or porous petroleum coke.

[0025] The average particle size Dv50 of the porous carbon matrix is ​​4 μm to 100 μm, and can be any value within this range, such as: 4 μm, 6 μm, 8 μm, 10 μm, 12 μm, 14 μm, 16 μm, 18 μm, 20 μm, 22 μm, 24 μm, 26 μm, 28 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, 100 μm, etc., but is not limited to the listed values; other unlisted values ​​within this range are also applicable. In this invention, particle size Dv50 refers to the volume median particle size of the material, representing the particle size corresponding to 50% of the material's volume distribution, which is a well-known meaning in the art. The particle size Dv50 of the porous carbon matrix provided in this embodiment of the invention can be determined using instruments and conventional methods known in the art. Specifically, 1g of material sample is weighed and added to 20ml of deionized water, then 50ul of 1% ethyl phenyl polyethylene glycol dispersant aqueous solution is added, and the mixture is sonicated for 5 minutes. The dispersion is then added to a Mastersizer 3000 laser particle size analyzer from Malvern Instruments Ltd. for particle size determination, and the Dv50 value is then read.

[0026] The porosity of the porous carbon matrix is ​​50% to 85%, and can be any value within this range, such as 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0027] The pore size of the porous carbon matrix is ​​2nm to 50nm, and can be any value within this range, such as: 2nm, 3nm, 4nm, 5nm, 6nm, 7nm, 8nm, 9nm, 10nm, 11nm, 12nm, 13nm, 14nm, 15nm, 16nm, 17nm, 18nm, 19nm, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm, 50nm, etc., but is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0028] The specific surface area of ​​the porous carbon matrix is ​​1000 m². 2 / g~3000m 2 / g can be any value within this range, for example: 1000m 2 / g、1200m 2 / g, 1400m 2 / g, 1600m 2 / g、1800m 2 / g、2000m 2 / g、2200m2 / g、2400m 2 / g、2600m 2 / g、2800m 2 / g、3000m 2 / g, etc., but not limited to the listed values; other unlisted values ​​within this range also apply.

[0029] The porous carbon matrix has a pore volume of 0.5 cm³. 3 / g~3.0cm 3 / g can be any value within this range, for example: 0.5cm 3 / g, 0.6cm 3 / g, 0.7cm 3 / g, 0.8cm 3 / g, 0.9cm 3 / g, 1.0cm 3 / g, 1.2cm 3 / g, 1.4cm 3 / g, 1.6cm 3 / g, 1.8cm 3 / g, 2.0cm 3 / g, 2.2cm 3 / g, 2.4cm 3 / g, 2.6cm 3 / g, 2.8cm 3 / g, 3.0cm 3 / g, etc., but not limited to the listed values; other unlisted values ​​within this range also apply.

[0030] The solid electrolyte layer has a continuous phase structure with a thickness between 1 nm and 25 nm. It can be any value within this range, such as 1 nm, 2 nm, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 15 nm, 16 nm, 17 nm, 18 nm, 19 nm, 20 nm, 21 nm, 22 nm, 23 nm, 24 nm, 25 nm, etc., but is not limited to the listed values; other unlisted values ​​within this range are also applicable. The thickness of the solid electrolyte layer is measured using conventional and known methods, such as transmission electron microscopy (TEM).

[0031] The solid electrolyte layer is formed by depositing the precursor of the solid electrolyte sequentially on the surface and pore walls of a porous carbon matrix that has undergone surface activation treatment using atomic layer deposition technology, and then heat treatment to allow the atoms of the precursor to migrate, diffuse, and transform into crystal phases.

[0032] The solid electrolyte in the solid electrolyte layer includes one or more of the following: fluoride oxide-based solid electrolyte, oxide-based solid electrolyte, and sulfide-based solid electrolyte.

[0033] Specifically, fluoride-oxide-based solid electrolytes include: Li 1.5 Al 0.5 Ge 1.5 (PO4) 2.9 F 0.1 Li 6.5 La3Zr 1.5 Ta 0.5 O 11.5 F 0.5 Li₂VO₂F, Li 1.2 Mn 0.8 Nb 0.2 O 1.6 F 0.4 Li m La n A a B b C c One or more of O6F; wherein, 1 < m + 3n < 5, 0 < m ≤ 2, 1 / 3 < n < 5 / 3; 0 ≤ a ≤ 2, 0 ≤ b ≤ 2, 0 ≤ c ≤ 2, a + b + c = 2; A is one or more of Zr, Ti, Hf, Si, Ge, Sn; B is one or more of Nb, Sb, Bi, V, Ta; C is one or more of W, Cr, Mo, Mn.

[0034] Oxide-based solid electrolytes include: garnet-type oxide solid electrolyte Li7Al3B12O 12 Perovskite oxide solid electrolyte Li 3x A2 2 / 3-x B2O3, NASICON-type oxide solid electrolyte Li 1+y A3 y B3 2-y One or more of (PO4)3, wherein 0.01≤x≤0.5 and 0.01≤y≤0.5; A1 is one or more of La, Ca, Sr, Ba, and K; B1 is one or more of Zr, Ta, Nb, and Hf; A2 is one or more of La, Al, Mg, Fe, and Ta; B2 is one or more of Ti, Nb, Sr, and Pr; A3 is one or more of Al, Y, Ga, Cr, In, Fe, Se, and La; and B3 is one or more of Ti, Ge, Ta, Zr, Sn, Fe, V, and Hf.

[0035] Sulfide-based solid electrolytes include: silver sulfide-germanium ore type solid electrolyte Li6PS5N1, LGPS type sulfide solid electrolyte Li11-z M1 2-z P 1+z S 12 Thio-LISICON type sulfide solid electrolytes (100-u)Li₂S-uP₂S₅, (100-u)Li₂S-uSiS₂, Li 4-v Ge 1-v P v S4 includes one or more of the following elements: 0 < z < 2, 0 < u < 100, 0 < v < 1; N1 includes any one of Cl, Br, and I elements; M1 includes any one of Ge, Si, and Sn elements.

[0036] This invention provides a method for preparing a composite porous carbon matrix material with in-situ coating of a solid electrolyte, such as... Figure 1 As shown, the specific steps include:

[0037] Step 110: Prepare an activated porous carbon matrix.

[0038] Specifically, this includes: performing surface activation treatment on a porous carbon matrix to introduce -OH bonds on the surface of the porous carbon matrix, thereby obtaining an activated porous carbon matrix.

[0039] The porous carbon matrix includes one or more of the following: porous resin carbon, porous biomass carbon, porous pitch coke, or porous petroleum coke.

[0040] The porous carbon matrix has an average particle size (Dv50) of 4 μm to 100 μm, a porosity of 50% to 85%, a pore size of 2 nm to 50 nm, and a specific surface area of ​​1000 m². 2 / g~3000m 2 / g, pore volume 0.5cm 3 / g~3cm 3 / g.

[0041] The surface activation treatment is either acid activation treatment or alkaline activation treatment.

[0042] Specifically, the acid activation treatment includes: immersing the porous carbon matrix in an acidic solution, stirring at 60℃~120℃ for 1 hour to 10 hours, washing with deionized water until neutral after the reaction, and drying at low temperature at 60℃~80℃ to obtain an activated porous carbon matrix with -OH bonds on its surface; the mass ratio of the porous carbon matrix to the acidic solution is 10%~50%; the acidic solution includes a nitric acid solution with a concentration of 20wt%-70wt% and / or hydrogen peroxide.

[0043] The alkaline activation treatment includes: placing porous carbon matrix and potassium hydroxide powder in a ball mill at a ratio of 1-5:5-9, and ball milling at 500-1000 rpm for 2-8 hours under an inert atmosphere. Zirconia balls are used as the milling media. After ball milling, residual potassium ions are removed by washing with dilute hydrochloric acid with a molar concentration of 0.1 mol / L to 1 M / L. After drying at 60℃ to 100℃, an activated porous carbon matrix with -OH bonds on the surface is obtained.

[0044] Step 120: Elements required to form a solid electrolyte are deposited on the surface and pore walls of an activated porous carbon matrix using atomic layer deposition technology to obtain a composite porous carbon precursor.

[0045] Specifically, the process involves placing an activated porous carbon matrix in a fluidized bed powder atomic layer deposition apparatus, heating it to 150°C–350°C, sequentially introducing a solid electrolyte precursor, and after each introduction of a precursor containing one or more elements, purging with an inert gas and intermittently introducing an oxidizing gas source to react, so that different elements in the precursor are deposited on the surface of the porous carbon matrix. The above deposition process is repeated 100–300 times to obtain a composite porous carbon precursor.

[0046] Among them, the fluidized bed powder atomic layer deposition equipment is a device that combines atomic layer deposition (ALD) technology with a laboratory-grade fluidized bed reactor. It adopts a uniquely designed fluidized bed reactor to introduce the ALD process into the powder materials industry, which can achieve atomic-level ultra-uniform deposition on the surface of micron and nano materials.

[0047] The precursor of the solid electrolyte is also the raw material for preparing the solid electrolyte. Each raw material includes one or more elements that are needed to form the solid electrolyte layer, and the raw material is suitable for atomic layer deposition technology. The volumetric flow rate of the gas of the solid electrolyte precursor is 50 sccm to 500 sccm.

[0048] Solid electrolytes include one or more of the following: fluoride-based solid electrolytes, oxide-based solid electrolytes, and sulfide-based solid electrolytes.

[0049] Fluoride oxide-based solid electrolytes include: Li 1.5 Al 0.5 Ge 1.5 (PO4) 2.9 F 0.1 Li 6.5 La3Zr 1.5 Ta 0.5 O 11.5 F 0.5 Li₂VO₂F, Li 1.2 Mn 0.8 Nb0.2 O 1.6 F 0.4 Li m La n A a B b C c One or more of O6F; wherein, 1 < m + 3n < 5, 0 < m ≤ 2, 1 / 3 < n < 5 / 3; 0 ≤ a ≤ 2, 0 ≤ b ≤ 2, 0 ≤ c ≤ 2, a + b + c = 2; A is one or more of Zr, Ti, Hf, Si, Ge, Sn; B is one or more of Nb, Sb, Bi, V, Ta; C is one or more of W, Cr, Mo, Mn.

[0050] Oxide-based solid electrolytes include: garnet-type oxide solid electrolyte Li7Al3B12O 12 Perovskite oxide solid electrolyte Li 3x A2 2 / 3-x B2O3, NASICON-type oxide solid electrolyte Li 1+y A3 y B3 2-y One or more of (PO4)3, wherein 0.01≤x≤0.5 and 0.01≤y≤0.5; A1 is one or more of La, Ca, Sr, Ba, and K; B1 is one or more of Zr, Ta, Nb, and Hf; A2 is one or more of La, Al, Mg, Fe, and Ta; B2 is one or more of Ti, Nb, Sr, and Pr; A3 is one or more of Al, Y, Ga, Cr, In, Fe, Se, and La; and B3 is one or more of Ti, Ge, Ta, Zr, Sn, Fe, V, and Hf.

[0051] Sulfide-based solid electrolytes include: silver sulfide-germanium ore type solid electrolyte Li6PS5N1, LGPS type sulfide solid electrolyte Li 11-z M1 2-z P 1+z S 12 Thio-LISICON type sulfide solid electrolytes (100-u)Li₂S-uP₂S₅, (100-u)Li₂S-uSiS₂, Li 4-v Ge 1-v P v S4 includes one or more of the following elements: 0 < z < 2, 0 < u < 100, 0 < v < 1; N1 includes any one of Cl, Br, and I elements; M1 includes any one of Ge, Si, and Sn elements.

[0052] The oxidizing gas source includes O3 and / or H2O; the gas volume flow rate of the oxidizing gas source is 50 sccm to 500 sccm.

[0053] The inert gas includes one or more of nitrogen, helium, or argon; the volumetric flow rate of the inert gas is 100 sccm to 1000 sccm.

[0054] Step 130: The composite porous carbon precursor is heat-treated to allow different elements to undergo atomic diffusion and crystal phase transformation to form a solid electrolyte layer, thereby obtaining a composite porous carbon matrix material with in-situ solid electrolyte coating.

[0055] The heat treatment specifically includes: placing the composite porous carbon precursor in a high-temperature device and heating it to 300℃~900℃ at a heating rate of 2℃ / min~5℃ / min, holding it at that temperature for 2 hours~8 hours, so that different elements on the surface of the composite porous carbon precursor undergo atomic diffusion and crystal phase transformation to form a solid electrolyte layer, thereby obtaining a composite porous carbon matrix material with in-situ coated solid electrolyte.

[0056] This invention uses a solid electrolyte precursor deposited by ALD to form an ultrathin and uniform chemical bonding layer on the surface of a porous carbon matrix and the pore walls. During heat treatment, atoms only need to migrate a short distance to complete the crystal phase transformation, rather than the interparticle diffusion driven by high temperature required in the traditional solid-state method. Therefore, the phase formation requirements can be met at a temperature of 300℃ to 900℃, which is much lower than the temperature of more than 1000℃ required for traditional solid-state sintering.

[0057] The composite porous carbon matrix material with in-situ solid electrolyte coating prepared by the preparation method provided in the embodiments of the present invention has a specific surface area change rate of less than or equal to 10% compared with the original porous carbon matrix. The composite porous carbon matrix material of the present invention can improve the ionic conductivity of the porous carbon material while maintaining a high specific surface area by coating the solid electrolyte material.

[0058] In this invention, the solid electrolyte deposited on the surface and pore walls of a porous carbon matrix using atomic layer deposition technology is preferably Li. m La n A a B b C c In O6F, 1 < m + 3n < 5, 0 < m ≤ 2, 1 / 3 < n < 5 / 3; 0 ≤ a ≤ 2, 0 ≤ b ≤ 2, 0 ≤ c ≤ 2, a + b + c = 2; A is one or more of Zr, Ti, Hf, Si, Ge, and Sn; B is one or more of Nb, Sb, Bi, V, and Ta; C is one or more of W, Cr, Mo, and Mn. This is because the Li m La n A a B bC c O6F solid electrolytes possess high density, high purity, high volumetric energy density, low internal resistance, and excellent ion conductivity. Furthermore, Li... m La n A a B b C c O6F solid electrolyte possesses a rigid framework structure with tunable elemental composition. The introduction of diverse coordination environments through multivalent cation doping facilitates the formation of open channels conducive to lithium-ion transport. Simultaneously, fluorine doping further enhances the material's polarity and interfacial wettability, improving interfacial contact with the electrolyte and electrodes, and reducing interfacial impedance. This invention forms Li in situ on the surface and pore walls of a porous carbon matrix. m La n A a B b C c The O6F solid electrolyte gives the resulting composite porous carbon matrix material excellent ionic conductivity and interfacial stability.

[0059] Li m La n A a B b C c Preferred precursors for O6F solid electrolytes include tris(2,2,6,6-tetramethyl-3,5-heptanedione)lanthanum (La(thd)3), niobium pentaethoxy (Nb(OEt)5), lithium bis(trimethylsilyl)amino (LiN(SiMe3)2), and hydrofluoric acid gas (HF).

[0060] The composite porous carbon matrix material with in-situ solid electrolyte coating provided in this invention can be applied in many fields, especially the battery field. The composite porous carbon matrix material can be further subjected to silicon nanomaterial deposition and carbon coating to obtain a silicon-carbon anode material, which can be used in the anode sheet of lithium-ion batteries, especially in the anode sheet of all-solid-state batteries.

[0061] To better understand the technical solution provided by the present invention, the following uses several specific examples to illustrate the preparation process and characteristics of the composite porous carbon matrix material with in-situ coating of solid electrolyte of the present invention.

[0062] Example 1 This invention provides a method for preparing a composite porous carbon matrix material for in-situ coating of solid electrolyte, which specifically includes the following steps.

[0063] (1) The porous carbon matrix was immersed in a 50wt% nitric acid solution and stirred at 80°C for 5 hours. After the reaction was completed, it was washed with deionized water until neutral and dried at 70°C to obtain an activated porous carbon matrix with -OH bonds on its surface. The porous carbon matrix was a porous resin carbon with a specific surface area of ​​2000 m². 2 / g, pore size 30nm, pore volume 2cm 3 / g.

[0064] (2) The activated porous carbon matrix is ​​placed in a fluidized bed atomic layer deposition reactor. The temperature of the atomic layer deposition process is set to 200℃. The process of one deposition using atomic layer deposition technology is as follows: First, La(thd)3 gas with a flow rate of 100 sccm is introduced with a pulse duration of 1 s, followed by purging with nitrogen gas at a flow rate of 200 sccm for 30 s. Then, O3 oxidizing gas with a flow rate of 100 sccm is introduced with a pulse duration of 0.5 s, followed by purging with nitrogen gas at a flow rate of 200 sccm for 20 s. This process forms CO-La-O bonds on the surface of the porous carbon matrix. The chemical equation for this process is: C-OH+La(thd)3→CO-La(thd)2+Hthd↑; CO-La(thd)2+O3→CO-La-O+4CO2↑+2CH3COCH3↑; Next, Nb(OEt)₅ gas with a flow rate of 100 sccm was introduced with a pulse duration of 1 s, followed by purging with nitrogen gas at a flow rate of 200 sccm for 30 s. Then, H₂O gas with a flow rate of 100 sccm was introduced with a pulse duration of 0.5 s, followed by purging with nitrogen gas at a flow rate of 200 sccm for 20 s. This process resulted in the formation of CO-Nb₂O₅ bonds on the surface of the porous carbon matrix. The chemical equation for this process is: C-OH+Nb(OEt)5→CO-Nb(OEt)4+EtOH↑; CO-Nb(OEt)4+4H2O→CO-Nb(OH)4→CO-Nb2O5; A LiN(SiMe3)2 gas with a flow rate of 100 sccm was introduced with a pulse duration of 2 s, followed by purging with nitrogen gas at a flow rate of 200 sccm for 40 s. Finally, HF gas with a flow rate of 100 sccm was introduced with a pulse duration of 0.5 s, followed by purging with nitrogen gas at a flow rate of 200 sccm for 20 s, forming CF-Li bonds on the surface of the porous carbon matrix. The chemical equation for this process is: C OH + LiN(SiMe3)2 → C O Li+HN(SiMe3)2↑; C O Li + HF → C F Li + H₂O↑; The deposition process was repeated 100 times to obtain a composite porous carbon precursor.

[0065] (3) The composite porous carbon precursor was placed in a tube furnace and heated to 600°C at a heating rate of 2°C / min under a nitrogen atmosphere. The temperature was held for 6 hours to allow the La, Nb, Li and F atoms in CO-La-O, CO-Nb2O5 and CF-Li to diffuse and undergo crystal phase transformation to form a solid electrolyte layer Li. 1.25 La 0.58 Nb₂O₆F was used to obtain in-situ coated solid electrolyte Li. 1.25 La 0.58 Nb2O6F composite porous carbon matrix material.

[0066] Example 2 This invention provides a process for preparing a composite porous carbon matrix material with in-situ coating of solid electrolyte. The difference from Example 1 is that the parameters of the porous carbon matrix used in step (1) are different, with a specific surface area of ​​1000 m². 2 / g, pore size 40nm, pore volume 1cm 3 / g, and the other preparation processes are the same as in Example 1.

[0067] Example 3 This invention provides a process for preparing a composite porous carbon matrix material with in-situ coating of solid electrolyte. The difference from Example 1 is that the parameters of the porous carbon matrix used in step (1) are different, with a specific surface area of ​​3000 m². 2 / g, pore size 50nm, pore volume 3cm 3 / g, and the other preparation processes are the same as in Example 1.

[0068] Example 4 This invention provides a preparation process for a composite porous carbon matrix material with in-situ coating of solid electrolyte. The difference from Example 1 is that the acid activation process in step (1) is different. Instead, the porous carbon matrix is ​​immersed in a 30wt% hydrogen peroxide solution and stirred at 100°C for 3 hours. After the reaction, it is washed with deionized water until neutral and dried at 80°C to obtain an activated porous carbon matrix with -OH bonds on its surface. All other preparation processes are the same as in Example 1.

[0069] Example 5 This invention provides a process for preparing a composite porous carbon matrix material with in-situ coating of solid electrolyte, which differs from Example 1 in the time and number of cycles of the deposition process in step (2), specifically: An activated porous carbon matrix was placed in a fluidized bed atomic layer deposition reactor and heated to 200°C for a single deposition process. The process was as follows: First, La(thd)3 gas was introduced at a flow rate of 100 sccm for 2 s, followed by purging with nitrogen gas at a flow rate of 200 sccm for 60 s. Then, O3 oxidizing gas was introduced at a flow rate of 100 sccm for 2 s, followed by purging with nitrogen gas at a flow rate of 200 sccm for 40 s, forming CO-La bonds on the surface of the porous carbon matrix. Next, Nb(OEt)5 gas was introduced at a flow rate of 100 sccm for 2 s, followed by purging with nitrogen gas at a flow rate of 200 sccm for 60 s. Next, H2O gas with a volumetric flow rate of 100 sccm is introduced with a pulse time of 2 s, followed by purging with nitrogen gas with a volumetric flow rate of 200 sccm for 40 s, forming CO-Nb(OH)4 bonds on the surface of the porous carbon matrix. Then, LiN(SiMe3)2 gas with a volumetric flow rate of 100 sccm is introduced with a pulse time of 2 s, followed by purging with nitrogen gas with a volumetric flow rate of 200 sccm for 60 s. Finally, HF gas with a volumetric flow rate of 100 sccm is introduced with a pulse time of 2 s, followed by purging with nitrogen gas with a volumetric flow rate of 200 sccm for 40 s, forming CF-Li bonds on the surface of the porous carbon matrix. The above deposition process is repeated 200 times to obtain a composite porous carbon precursor.

[0070] The other preparation processes are the same as in Example 1.

[0071] Example 6 This invention provides a process for preparing a composite porous carbon matrix material with in-situ solid electrolyte coating. The difference from Example 1 is that the heat treatment conditions in step (3) are different. Instead, the composite porous carbon precursor is placed in a tube furnace and heated to 700°C at a rate of 5°C / min under a nitrogen atmosphere, and held for 4 hours. This allows the La, Nb, Li, and F atoms in CO-La, CO-Nb2O5, and CF-Li to diffuse and undergo phase transformation, forming a solid electrolyte layer Li. 1.25 La 0.58 Nb₂O₆F was used to obtain in-situ coated solid electrolyte Li. 1.25 La 0.58 A composite porous carbon matrix material of Nb₂O₆F. All other preparation processes are the same as in Example 1.

[0072] Example 7 This invention provides a method for preparing a composite porous carbon matrix material with in-situ coated solid electrolyte. The method differs from Example 1 in that the precursor for the solid electrolyte in step (2) is different, and the type of solid electrolyte layer formed in-situ in step (3) is also different. The composition of the solid electrolyte layer is Li. 1.3 Al 0.3 Ti 1.7 (PO4)3 (LATP) is prepared by the following steps.

[0073] (1) Same as step (1) in Example 1.

[0074] (2) The activated porous carbon matrix is ​​placed in a fluidized bed atomic layer deposition reactor. The temperature of the atomic layer deposition process is 200℃. The deposition process is as follows: First, aluminum isopropoxide (Al(OC3H7)3) gas with a gas volume flow rate of 100 sccm is introduced with a pulse time of 1 s, and then nitrogen gas with a gas volume flow rate of 200 sccm is purged for 30 s. Then, an oxidizing gas source O3 with a gas volume flow rate of 100 sccm is introduced with a pulse time of 0.5 s, and then nitrogen gas with a gas volume flow rate of 200 sccm is purged for 20 s, forming CO-Al bonds on the surface of the porous carbon matrix. Then, tetrabutyl titanate (Ti(OC4H9)4) gas with a gas volume flow rate of 100 sccm was introduced with a pulse time of 1 s, and nitrogen gas with a gas volume flow rate of 200 sccm was purged for 30 s. Then, H2O gas with a gas volume flow rate of 100 sccm was introduced with a pulse time of 0.5 s, and nitrogen gas with a gas volume flow rate of 200 sccm was purged for 20 s, forming CO-Ti(OH)4 bonds on the surface of the porous carbon matrix. Lithium carbonate (Li2CO3) gas with a volumetric flow rate of 100 sccm was introduced with a pulse duration of 2 s, followed by purging with nitrogen gas with a volumetric flow rate of 200 sccm for 40 s; finally, ammonium dihydrogen phosphate (NH4H2PO4) gas with a volumetric flow rate of 100 sccm was introduced with a pulse duration of 0.5 s, followed by purging with nitrogen gas with a volumetric flow rate of 200 sccm for 20 s, forming CP-Li bonds on the surface of the porous carbon matrix. The deposition process was repeated 100 times to obtain a composite porous carbon precursor.

[0075] (3) The composite porous carbon precursor was placed in a tube furnace and heated to 800°C at a heating rate of 5°C / min under a nitrogen atmosphere. The temperature was held for 8 hours to allow Al, Ti, Li and P atoms in CO-Al, CO-Ti(OH)4 and CP-Li to diffuse and undergo crystal phase transformation to form a solid electrolyte layer Li. 1.3 Al 0.3 Ti1.7 (PO4)3, to obtain in-situ coated solid electrolyte Li 1.3 Al 0.3 Ti 1.7 (PO4)3 composite porous carbon matrix material.

[0076] To better illustrate the effects of the embodiments of the present invention, a comparative example is provided to be made with the embodiments described above.

[0077] Comparative Example 1 This comparative example directly tests the porous carbon matrix used in step (1) of Example 1.

[0078] Comparative Example 2 The difference between this comparative example and Example 1 is that a solid electrolyte Li was prepared in advance. 1.25 La 0.58 Nb2O6F, followed by solid electrolyte Li 1.25 La 0.58 Nb₂O₆F is directly blended with a porous carbon matrix, allowing Li to... 1.25 La 0.58 The Nb2O6F coating is applied to the surface and pore walls of a porous carbon matrix. The specific steps are as follows.

[0079] (1) Li2CO3, La2O3, Nb2O5, and LiF were mixed evenly in a molar ratio of 0.625:0.29:1:1 and placed in a tube furnace. Nitrogen gas was introduced into the tube furnace at a gas flow rate of 1.5 L / min. Under the nitrogen atmosphere, the temperature was raised to 1000℃ at a heating rate of 2℃ / min and held for 6 hours. After discharging, breaking up, and sieving, a fluoride solid electrolyte Li with a particle size Dv50 of 100 nm was obtained. 1.25 La 0.58 Nb2O6F.

[0080] (2) The solid electrolyte Li 1.25 La 0.58 Nb₂O₆F and the porous carbon matrix used in Example 1 were placed in a ball mill at a mass ratio of 5:95 and ball-milled at 500 rpm for 6 hours to allow Li to... 1.25 La 0.58 Nb2O6F is coated on the surface and pore walls of a porous carbon matrix to obtain a composite porous carbon matrix material.

[0081] Comparative Example 3 The difference between this comparative example and Example 7 is that commercially available solid electrolyte Li was directly used. 1.3 Al 0.3 Ti 1.7(PO4)3 (LATP) was directly placed in a ball mill with the porous carbon matrix used in Example 1 at a mass ratio of 5:95 and ball milled at 500 rpm for 6 hours to coat the surface and pore walls of the porous carbon matrix with LATP, thus obtaining a composite porous carbon matrix material.

[0082] The composite porous carbon matrix materials of Examples 1-7 and the materials of Comparative Examples 1-2 were subjected to performance tests. The specific test items and test methods are as follows.

[0083] 1. Ionic conductivity and surface resistance testing.

[0084] (1) Ionic conductivity testing was performed using electrochemical impedance spectroscopy (EIS) on an electrochemical workstation. Specifically, the composite porous carbon matrix materials of Examples 1-7 and the materials of Comparative Examples 1-3 were first placed in a test mold in a certain amount, and continuously pressurized into sheet-like materials before being connected to the electrochemical workstation. To ensure the accuracy of the test, the test battery was placed in a constant temperature chamber for temperature control. In the EIS test, the frequency range was set from 0.01 Hz to 1 MHz, and the amplitude voltage was set to 10 mV to accurately measure the resistance of the material. Then, by analyzing the Nyquist impedance spectrum, the ionic conductivity of the material can be calculated using the following formula: In the process of determining ionic conductivity, d in the formula represents the thickness of the sheet material, R is the impedance value of the electrolyte read from the Nyquist impedance diagram of EIS, and S represents the effective contact area between the sheet material and the stainless steel inert electrode. To ensure the accuracy of the measurement, when testing the ionic conductivity at different temperatures, the constant temperature chamber needs to be set to the target temperature and maintained for half an hour to allow the test battery to reach thermal equilibrium. This step ensures the stability of the test environment, thereby allowing for accurate measurement of the ionic conductivity of the solid electrolyte at various temperatures. The ionic conductivity tests of this invention were all conducted at 25±2℃ and humidity less than 50%. Detailed test data are shown in Table 1.

[0085] (2) Calculate the surface resistance. The formula is: Surface resistance = impedance value R × area S of sheet material.

[0086] 2. Calculate the specific surface area retention rate.

[0087] Specific surface area retention rate = 1 - (specific surface area of ​​the composite porous carbon matrix material before coating - specific surface area of ​​the porous carbon matrix after coating) / specific surface area of ​​the porous carbon matrix before coating.

[0088] In this invention, the testing methods for specific surface area, average pore size, and pore volume are performed using a specific surface area analyzer (model: Micromeritics ASAP2460): The sample to be tested is first sieved using a 200-mesh sieve; then, degassing is performed, typically by placing the sample in a vacuum and heating it at 200°C for several hours (up to 6 hours). Next, nitrogen gas is introduced under a constant low temperature (-196°C), and the nitrogen pressure is controlled to allow the sample to adsorb and desorb at different pressures, obtaining isothermal adsorption-desorption curves. Then, based on the isothermal adsorption-desorption curves, the specific surface area of ​​the sample is calculated using BET fitting, and the average pore size and pore volume are calculated using a t-plot model.

[0089] The results of the calculation of the rate of change of specific surface area are detailed in Table 1.

[0090] 3. Electronic conductivity test: The test was conducted using a four-probe probe. The test results are detailed in Table 1.

[0091] Table 1 summarizes the test data for Examples 1-7 and Comparative Examples 1-3.

[0092] Table 1 As can be seen from the data in Table 1, the ionic conductivity of Examples 1-6 is much higher than that of Comparative Examples 1-2, the sheet resistance of Examples 1-6 is significantly lower than that of Comparative Examples 1-2, the electrochemical window of Examples 1-6 is significantly higher than that of Comparative Examples 1-2, and the specific surface area change rate of Examples 1-6 is significantly lower than that of Comparative Examples 1-2. Similarly, the ionic conductivity of Example 7 is much higher than that of Comparative Example 3, the sheet resistance of Example 7 is significantly lower than that of Comparative Example 3, the electrochemical window of Example 7 is significantly higher than that of Comparative Example 3, and the specific surface area change rate of Example 7 is significantly lower than that of Comparative Example 3. This is because Comparative Example 1 did not involve in-situ coating of a solid electrolyte, and its ionic conductivity is significantly lower than that of the Examples. In Comparative Examples 2 and 3, solid electrolytes were directly co-coated with porous carbon matrices. Although this improved the ionic conductivity to some extent, the phase of the solid electrolyte coating layer was not continuous. Therefore, the ionic conductivity of Comparative Example 2 was significantly lower than that of Example 1 with a continuous phase solid electrolyte coating layer, and the ionic conductivity of Comparative Example 3 was significantly lower than that of Example 7 with a continuous phase solid electrolyte coating layer. In addition, the solid electrolyte coating process in Comparative Examples 2 and 3 easily blocked the pores of the porous carbon matrix, which was not conducive to its subsequent application.

[0093] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a composite porous carbon matrix material with in-situ coating of solid electrolyte, characterized in that, The composite porous carbon matrix material includes: a porous carbon matrix, and a solid electrolyte layer in situ coated on the surface and pore walls of the porous carbon matrix; The solid electrolyte layer has a continuous phase structure; the solid electrolyte in the solid electrolyte layer includes one or more of the following: fluoride oxide-based solid electrolyte, oxide-based solid electrolyte, and sulfide-based solid electrolyte. The solid electrolyte layer is formed by depositing the precursor of the solid electrolyte sequentially on the surface and pore walls of a porous carbon matrix that has undergone surface activation treatment using atomic layer deposition technology, and then heat-treating the precursor atoms to allow them to migrate, diffuse, and transform into crystal phases. The preparation method of the composite porous carbon matrix material specifically includes: The preparation of an activated porous carbon matrix includes: performing a surface activation treatment on the porous carbon matrix to make the surface of the porous carbon matrix contain -OH bonds, thereby obtaining an activated porous carbon matrix; A composite porous carbon precursor is obtained by depositing the elements required to form a solid electrolyte on the surface and pore walls of an activated porous carbon matrix using atomic layer deposition technology. The process includes: placing the activated porous carbon matrix in a fluidized bed powder atomic layer deposition apparatus, heating it to 150℃~350℃, sequentially introducing the gas of the solid electrolyte precursor, and after each introduction of a precursor containing one or more elements, purging with an inert gas and intermittently introducing an oxidizing gas source to react, so that different elements in the precursor are deposited on the surface of the porous carbon matrix. The above deposition process is repeated 100 to 300 times to obtain the composite porous carbon precursor. The composite porous carbon precursor is heat-treated to allow different elements to undergo atomic diffusion and crystal phase transformation to form a solid electrolyte layer, thus obtaining a composite porous carbon matrix material with in-situ solid electrolyte coating.

2. The preparation method according to claim 1, characterized in that, The porous carbon matrix includes one or more of the following: porous resin carbon, porous biomass carbon, porous pitch coke, or porous petroleum coke. The average particle size Dv50 of the porous carbon matrix is 4 μm to 100 μm, the porosity is 50% to 85%, the pore size is 2 nm to 50 nm, the specific surface area is 1000 m 2 / g to 3000 m 2 / g, the pore volume is 0.5 cm 3 / g to 3 cm 3 / g.

3. The preparation method according to claim 1, characterized in that, The surface activation treatment is either an acidic activation treatment or an alkaline activation treatment; The acid activation treatment includes: immersing a porous carbon matrix in an acidic solution, stirring at 60℃~120℃ for 1 hour~10 hours, washing with deionized water until neutral after the reaction, and drying at a low temperature of 60℃~80℃ to obtain an activated porous carbon matrix with -OH bonds on its surface; the mass ratio of the porous carbon matrix to the acidic solution is 10%~50%; the acidic solution includes a nitric acid solution with a concentration of 20wt%-70wt% and / or hydrogen peroxide; The alkaline activation treatment includes: placing a porous carbon matrix and potassium hydroxide powder in a ball mill at a ratio of 1-5:5-9, and ball milling at 500-1000 rpm for 2-8 hours under an inert atmosphere. Zirconia balls are used as the milling media. After ball milling, residual potassium ions are removed by washing with dilute hydrochloric acid with a molar concentration of 0.1 mol / L-1 M / L. After drying at 60℃-100℃, an activated porous carbon matrix with -OH bonds on its surface is obtained.

4. The preparation method according to claim 1, characterized in that, The volumetric flow rate of the gas precursor for the solid electrolyte is 50 sccm to 500 sccm; The solid electrolyte in the solid electrolyte layer includes one or more of the following: fluoride-based solid electrolyte, oxide-based solid electrolyte, and sulfide-based solid electrolyte.

5. The preparation method according to claim 1, characterized in that, The fluoride-based solid electrolyte includes: Li 1.5 Al 0.5 Ge 1.5 (PO4) 2.9 F 0.1 Li 6.5 La3Zr 1.5 Ta 0.5 O 11.5 F 0.5 Li₂VO₂F, Li 1.2 Mn 0.8 Nb 0.2 O 1.6 F 0.4 Li m La n A a B b C c One or more of O6F; wherein, 1 < m + 3n < 5, 0 < m ≤ 2, 1 / 3 < n < 5 / 3; 0 ≤ a ≤ 2, 0 ≤ b ≤ 2, 0 ≤ c ≤ 2, a + b + c = 2; A is one or more of Zr, Ti, Hf, Si, Ge, Sn; B is one or more of Nb, Sb, Bi, V, Ta; C is one or more of W, Cr, Mo, Mn; The oxide-based solid electrolyte includes: garnet-type oxide solid electrolyte Li7Al3B12O 12 Perovskite oxide solid electrolyte Li 3x A2 2 / 3-x B2O3, NASICON-type oxide solid electrolyte Li 1+y A3 y B3 2-y One or more of (PO4)3, wherein 0.01≤x≤0.5, 0.01≤y≤0.5; A1 is one or more of La, Ca, Sr, Ba, K, and B1 is one or more of Zr, Ta, Nb, Hf; A2 is one or more of La, Al, Mg, Fe, Ta, and B2 is one or more of Ti, Nb, Sr, Pr; A3 is one or more of Al, Y, Ga, Cr, In, Fe, Se, La, and B3 is one or more of Ti, Ge, Ta, Zr, Sn, Fe, V, Hf. The sulfide-based solid electrolytes include: argillium sulfide-germanium ore type solid electrolyte Li6PS5N1, and LGPS type sulfide solid electrolyte Li... 11-z M1 2-z P 1+z S 12 Thio-LISICON type sulfide solid electrolytes (100-u)Li₂S-uP₂S₅, (100-u)Li₂S-uSiS₂, Li 4-v Ge 1-v P v S4 includes one or more of the following elements: 0 < z < 2, 0 < u < 100, 0 < v < 1; N1 includes any one of Cl, Br, and I elements; M1 includes any one of Ge, Si, and Sn elements.

6. The preparation method according to claim 1, characterized in that, The oxidation gas source includes O3 and / or H2O; the volumetric flow rate of the oxidation gas source is 50 sccm to 500 sccm. The inert gas includes one or more of nitrogen, helium, or argon; the volumetric flow rate of the inert gas is 100 sccm to 1000 sccm.

7. The preparation method according to claim 1, characterized in that, The heat treatment specifically includes: placing the composite porous carbon precursor in a high-temperature device and heating it to 300℃~900℃ at a heating rate of 2℃ / min~5℃ / min, holding it at that temperature for 2 hours~8 hours, so that different elements on the surface of the composite porous carbon precursor undergo atomic diffusion and crystal phase transformation to form a solid electrolyte layer, thereby obtaining a composite porous carbon matrix material with in-situ coated solid electrolyte.

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