A silicon-carbon negative electrode material based on a 3D-printed solid electrolyte skeleton and a preparation method and solid-state battery thereof

Abstract

The application belongs to the technical field of solid-state batteries, and relates to a silicon-carbon negative electrode material based on a 3D-printed solid-state electrolyte framework and a preparation method thereof and a solid-state battery. The application discloses a silicon-carbon negative electrode material based on a 3D-printed solid-state electrolyte framework, which has a three-layer structure and sequentially comprises a current collector, a 3D-printed solid-state electrolyte framework and an interface layer; the 3D-printed solid-state electrolyte framework comprises a 3D-printed solid-state electrolyte framework base body and silicon particles and a carbon layer deposited in the interstices and on the surface of the base body in sequence; and the interface layer comprises nitrogen-containing material and / or fluorine-containing material. The solid-state battery prepared based on the silicon-carbon negative electrode material has good performance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of solid-state batteries, and relates to a silicon-carbon negative electrode material based on a 3D-printed solid-state electrolyte framework and a preparation method thereof and a solid-state battery. BACKGROUND

[0002] With the rapid development of new energy vehicles and portable electronic devices, the demand for high-energy-density and high-safety batteries is increasingly urgent. At present, commercial lithium-ion batteries mostly use liquid electrolytes. However, the liquid electrolyte has safety hazards such as volatility, flammability and leakage, and is difficult to be compatible with high-voltage positive electrode materials and high-specific-capacity negative electrode materials, which limits the improvement of battery energy density and cannot meet the needs of high-end application scenarios such as long-range electric vehicles. Solid-state batteries use solid-state electrolytes to replace traditional liquid electrolytes, have higher safety and energy density potential, and are regarded as an important development direction of next-generation battery technology. Among the key materials of solid-state batteries, the performance of the negative electrode material is crucial. The theoretical capacity of the traditional graphite-based negative electrode is only 372 mAh / g, which has reached its performance bottleneck. The silicon-based negative electrode has an ultra-high theoretical capacity of 3500 mAh / g (about 10 times that of graphite), abundant natural resources and lower cost, and becomes an ideal candidate material for improving the energy density of solid-state batteries.

[0003] At present, the application of silicon-based negative electrodes in solid-state batteries still faces many challenges, and the existing technical solutions have obvious defects. One common method is to mix pure silicon powder with a conductive agent and a binder to prepare a slurry, and to make an electrode sheet through a coating process. However, silicon will expand by more than 300% during charging and discharging, which will cause the electrode structure to break and the active material to fall off, and will repeatedly damage and generate a solid electrolyte interface (SEI) film, causing rapid capacity decay of the battery. Another improvement scheme is to use a vapor deposition technology to load silicon into a carbon framework to prepare a silicon-carbon composite material, and then to make an electrode sheet through a traditional coating process. Although this method can alleviate the problem of volume expansion to some extent, the composite structure of the carbon framework and silicon often lacks ordered ion transport channels, which will hinder the diffusion of lithium ions and affect the rate performance and fast-charging ability of the battery, and the interface compatibility between silicon and the solid-state electrolyte is poor, which further restricts the cycle stability of the battery. Therefore, developing a silicon-based negative electrode structure that can simultaneously solve the problems of volume expansion, electronic / ionic conduction and interface compatibility is a key to promoting the practicality of high-energy-density solid-state batteries. SUMMARY

[0004] The purpose of the present application is to solve the above-mentioned problems existing in the prior art, and a silicon-carbon negative electrode material based on a 3D printed solid electrolyte framework is proposed, which takes a current collector as a substrate, and sequentially loads a 3D printed solid electrolyte framework and an interface layer on the surface of the current collector, wherein the voids and surface of the 3D printed solid electrolyte framework are sequentially deposited with silicon particles and a carbon layer, thereby effectively improving the electrochemical performance of the solid-state battery.

[0005] One purpose of the present application is achieved by the following technical solutions:

[0006] A silicon-carbon negative electrode material based on a 3D printed solid electrolyte framework, which is a three-layer structure and sequentially includes a current collector, a 3D printed solid electrolyte framework, and an interface layer; the 3D printed solid electrolyte framework includes a 3D printed solid electrolyte framework matrix and silicon particles and a carbon layer sequentially deposited in the voids and surface of the framework matrix; and the interface layer includes nitrogen-containing material and / or fluorine-containing material.

[0007] Preferably, the mass ratio of the 3D printed solid electrolyte framework matrix, silicon particles, and carbon layer in the 3D printed solid electrolyte framework is (10-75):(20-70):(5-20).

[0008] Further preferably, the mass ratio of the 3D printed solid electrolyte framework matrix, silicon particles, and carbon layer is (30-60):(40-60):(5-10).

[0009] Further preferably, the mass of the silicon particles in the 3D printed solid electrolyte framework is > the mass of the 3D printed solid electrolyte framework matrix > the mass of the carbon layer.

[0010] Further preferably, the mass ratio of the silicon particles and the carbon layer is (2-9):1.

[0011] Further preferably, the mass ratio of the 3D printed solid electrolyte framework matrix, silicon particles, and carbon layer is 40:50:10.

[0012] Preferably, the current collector includes one of copper foil, silver foil, and aluminum foil.

[0013] Further preferably, the thickness of the current collector is 3-20 pm.

[0014] Preferably, the distance between the current collector and the interface layer is 10-200 pm.

[0015] Further preferably, the distance between the current collector and the interface layer is 50-120 pm.

[0016] Preferably, the thickness of the interface layer is 0.1-20 pm.

[0017] Further preferably, the thickness of the interface layer is 0.1-5 pm.

[0018] Further preferably, the thickness of the interface layer is 0.5-2 μm.

[0019] Preferably, the nitrogen-containing material comprises one or more of silicon nitride, boron nitride, lithium nitride, magnesium nitride, aluminum nitride, titanium nitride, and tantalum nitride.

[0020] The fluorine-containing material comprises one or more of silicon fluoride, lithium fluoride, magnesium fluoride, aluminum fluoride, titanium fluoride, and tantalum fluoride.

[0021] Preferably, the interface layer is formed by coating the interface layer slurry on the side of the 3D-printed solid-state electrolyte skeleton away from the current collector, and dried.

[0022] Further preferably, the solid content of the interface layer slurry is 5-50 wt%.

[0023] Further preferably, the interface layer slurry comprises the nitrogen-containing material and / or the fluorine-containing material, the binder, and the solvent in a mass ratio of (80-95):(1-10):(1-80).

[0024] Further preferably, the binder comprises one or more of polymethyl methacrylate (PMMA), tripropylene glycol diacrylate (TPGDA), polyurethane acrylate (PUA), polyester acrylate, polyvinylidene fluoride (PVDF), styrene-butadiene rubber (SBR), nitrile-butadiene rubber (NBR), polyacrylic acid (PAA), polyimide (PI), and polytetrafluoroethylene (PTFE).

[0025] The solvent comprises one or more of ethanol, dimethylformamide (DMF), N-methyl pyrrolidone (NMP), methanol, ethanol, isopropyl alcohol, ethyl acetate, acetone, benzene, toluene, dichloromethane, deionized water, and ethylene glycol.

[0026] Preferably, the method for preparing the 3D-printed solid-state electrolyte skeleton comprises: placing the 3D-printed solid-state electrolyte skeleton substrate in a silane gas environment, depositing silicon particles on the voids and surface of the substrate by chemical vapor deposition, and replacing the gas environment with a carbon source gas to deposit a carbon layer.

[0027] Further preferably, the silane gas comprises one or more of monosilane, dichlorosilane, trichlorosilane, silicon tetrachloride, and hexachlorodisilane.

[0028] Further preferably, the carbon source gas comprises one or more of acetylene, methane, ethylene, propane, and propylene.

[0029] Preferably, the average particle size of the silicon particles is 5-500 nm.

[0030] As preferred, the average thickness of the carbon layer is 10-30 nm.

[0031] As preferred, the surface of the silicon particles in the 3D-printed solid-state electrolyte skeleton is wrapped with a carbon layer.

[0032] As preferred, the silicon particles in the 3D-printed solid-state electrolyte skeleton are amorphous silicon.

[0033] As preferred, there are voids in the 3D-printed solid-state electrolyte skeleton matrix.

[0034] Further preferred, the voids in the 3D-printed solid-state electrolyte skeleton matrix are 0.1-20 mm.

[0035] As preferred, the particle size of the silicon particles is < the voids of the 3D-printed solid-state electrolyte skeleton matrix.

[0036] Further preferred, the particle size of the silicon particles is 0.001-80% of the voids of the 3D-printed solid-state electrolyte skeleton matrix.

[0037] As preferred, the shape of the 3D-printed solid-state electrolyte skeleton matrix comprises one or more of a columnar structure, a porous structure.

[0038] Further preferred, the shape of the 3D-printed solid-state electrolyte skeleton matrix is a columnar structure, the shape of the 3D-printed solid-state electrolyte skeleton matrix is a columnar structure, the 3D-printed solid-state electrolyte skeleton matrix is a columnar array composed of a plurality of columnar solid-state electrolyte skeletons, wherein the diameter of a single columnar solid-state electrolyte skeleton is 0.1-20 mm, and the voids between two adjacent columnar solid-state electrolyte skeletons are 0.1-10 mm.

[0039] Further preferred, the diameter of a single columnar solid-state electrolyte skeleton in the 3D-printed solid-state electrolyte skeleton columnar array is 0.5-10 mm, and the voids between two adjacent columnar solid-state electrolyte skeletons are 0.5-5 mm.

[0040] Further preferred, the shape of the 3D-printed solid-state electrolyte skeleton matrix is a porous structure, and the porous structure is a network structure composed of interconnected or closed pores.

[0041] Further preferred, the voids of the porous structure are 0.5-10 mm.

[0042] As preferred, the 3D-printed solid-state electrolyte skeleton is obtained by 3D printing the 3D printing slurry on the surface of the current collector.

[0043] Further preferred, the solid content of the 3D printing slurry is 10-50 wt%.

[0044] Further preferably, the raw materials of the 3D printing paste include a solid-state electrolyte, a binder, and a solvent, and the mass ratio of the solid-state electrolyte, the binder, and the solvent is (80-95):(1-10):(1-80);

[0045] The solid-state electrolyte includes one or more of an oxide electrolyte, a sulfide electrolyte, a halide electrolyte, and a polymer electrolyte.

[0046] The binder includes one or more of polymethyl methacrylate (PMMA), tripropylene glycol diacrylate (TPGDA), polyurethane acrylate (PUA), polyester acrylate, polyvinylidene fluoride (PVDF), styrene-butadiene rubber (SBR), nitrile rubber (NBR), polyacrylic acid (PAA), polyimide (PI), and polytetrafluoroethylene (PTFE).

[0047] The solvent includes one or more of ethanol, dimethylformamide (DMF), N-methyl pyrrolidone (NMP), methanol, ethanol, isopropyl alcohol, ethyl acetate, acetone, benzene, toluene, dichloromethane, deionized water, and ethylene glycol.

[0048] More preferably, the oxide electrolyte includes one or more of lithium titanium aluminum phosphate (LATP), lithium lanthanum zirconium oxide (LLZO), lithium lanthanum titanium oxide (LLTO), lithium vanadium phosphorus oxide, and lithium lanthanum titanate.

[0049] The sulfide electrolyte includes one or more of lithium phosphorus sulfide chloride (LPSCl), lithium germanium phosphorus sulfide (LGPS), lithium phosphorus sulfide, and lithium silicon phosphorus sulfide.

[0050] The second object of the application is achieved by the following technical solution:

[0051] A method for preparing a silicon-carbon negative electrode material based on a 3D-printed solid-state electrolyte framework, including: 3D printing a 3D-printed solid-state electrolyte framework base on one side of a current collector by using a 3D printing paste; placing the 3D-printed solid-state electrolyte framework base in a silane gas environment, and depositing silicon particles on the voids and surface of the 3D-printed solid-state electrolyte framework base by using a chemical vapor deposition process; replacing the gas environment with a carbon source gas to deposit a carbon layer, thereby obtaining a 3D-printed solid-state electrolyte framework; and coating an interface layer paste on the side of the 3D-printed solid-state electrolyte framework that is away from the current collector to form an interface layer.

[0052] Preferably, the method for preparing the 3D-printed solid-state electrolyte framework includes: placing a 3D-printed solid-state electrolyte framework base in a fluidized bed, introducing silane gas, and heating to 500-1000℃ to deposit silicon particles on the voids and surface of the 3D-printed solid-state electrolyte framework base; naturally cooling to room temperature, replacing the gas environment with a carbon source gas, and heating to 500-1000℃ to deposit a carbon layer, thereby obtaining a 3D-printed solid-state electrolyte framework with silicon-carbon deposition on the voids and surface.

[0053] Preferably, the preparation method of the interface layer comprises: preparing an interface layer slurry by mixing nitrogen-containing material and / or fluorine-containing material, binder and solvent in a mass ratio of (80-95):(1-10):(1-80), coating the interface layer slurry on the surface of the 3D-printed solid electrolyte framework away from the current collector, and drying to form the interface layer.

[0054] The third object of the application is achieved by the following technical solutions:

[0055] A solid-state battery comprises a negative electrode sheet, wherein the negative electrode sheet comprises the aforementioned silicon-carbon negative electrode material based on the 3D-printed solid electrolyte framework.

[0056] Preferably, the solid-state battery further comprises a positive electrode sheet and a solid electrolyte sheet.

[0057] Further preferably, the active material of the positive electrode sheet comprises one or more of ternary nickel-cobalt-manganese oxide (NCM), ternary nickel-cobalt-aluminum oxide (NCA), lithium cobalt oxide (LCO), lithium iron phosphate (LFP), lithium vanadium phosphate (LVP), and lithium vanadium fluorophosphate (LFVP).

[0058] Further preferably, the raw materials of the positive electrode sheet comprise active material, binder, conductive agent, and solid electrolyte.

[0059] Further preferably, the solid electrolyte sheet is prepared by tabletting the raw materials comprising solid electrolyte.

[0060] Alternatively, the solid electrolyte sheet is prepared by one or more steps of flow casting, drying, debinding, cold pressing, low-temperature sintering, and 3D printing from the solid electrolyte slurry.

[0061] Further preferably, the solid electrolyte slurry is the aforementioned 3D printing slurry.

[0062] Further preferably, the solid electrolyte in the solid electrolyte sheet is the same as the solid electrolyte in the 3D printing slurry of the silicon-carbon negative electrode material based on the 3D-printed solid electrolyte framework.

[0063] Compared with the prior art, the application has the following beneficial effects:

[0064] 1. The application constructs a 3D-printed solid electrolyte three-dimensional framework matrix by 3D printing, precisely designs the voids of the framework matrix to adapt to the volume change of silicon particles, effectively suppresses material fragmentation and interface peeling, and significantly improves the cycle stability.

[0065] 2、The application sequentially deposits silicon particles and a carbon layer in a 3D printed solid electrolyte skeleton matrix, coats the silicon particles with a carbon layer, isolates moisture and oxygen, significantly improves the air stability of the material, and reduces storage and processing requirements; the carbon layer also constructs an efficient electron conduction network, buffers the volume expansion of silicon particles, prevents rupture, and significantly improves the cycle life.

[0066] 3、The silicon-carbon negative electrode material based on the 3D printed solid electrolyte skeleton of the application introduces an interface protection layer, in which lithium nitride or lithium fluoride is generated in situ during the operation of the solid-state battery, effectively isolating the side reaction of the electrode and the electrolyte, greatly reducing the interface impedance; at the same time, it promotes uniform deposition of lithium ions, inhibits dendrite growth, and improves safety. BRIEF DESCRIPTION OF DRAWINGS

[0067] Figure 1 The figure is a schematic diagram of the silicon-carbon negative electrode material based on the 3D printed solid electrolyte skeleton of the application. DETAILED DESCRIPTION

[0068] The technical solutions of the application will be further described and explained below through specific examples, and it should be understood that the specific examples described herein are only used to help understand the application, and are not used to limit the specific application.

[0069] If not specifically stated, the raw materials used in the examples of the application are all commonly used raw materials in the art, and the methods used in the examples are all conventional methods in the art.

[0070] In this paper, the schematic diagram of the silicon-carbon negative electrode material based on the 3D printed solid electrolyte skeleton of the application is shown in Figure 1 .

[0071] In this paper, the current collector (including copper foil) is pretreated, and the pretreatment includes one or more of water washing, alcohol washing, ultrasonic cleaning and drying.

[0072] In this paper, the distance between the current collector and the interface layer is the height of the 3D printed solid electrolyte skeleton matrix.

[0073] In this paper, different structures of 3D printed solid electrolyte skeleton matrixes that meet the void requirements of the application can achieve the good deposition effect and solid-state battery performance improvement effect described in the application.

[0074] In this paper, the test method includes:

[0075] Cycling performance: the solid-state battery was subjected to: 1, 25℃, 0.33C constant current charging to 4.2V, 4.2V constant voltage charging until the current decreased to 0.05C; 2, standing for 10min; 3, 0.33C constant current discharging to 2.5V; 4, standing for 10min; 5, repeating the preceding steps 1~4, 500 times.

[0076] Negative electrode sheet expansion rate: 0.33C constant current charging to 4.2V, 4.2V constant voltage charging until the current decreased to 0.05C, disassembling the solid-state battery, measuring the thickness of the negative electrode sheet after full charging; negative electrode sheet expansion rate = ((negative electrode sheet thickness after full charging-negative electrode sheet thickness before full charging) / negative electrode sheet thickness before full charging) x 100%.

[0077] Rate performance: 3C constant current charging to 4.2V capacity, 3C rate capacity retention rate = (3C charging capacity / 0.33C charging capacity) x 100%.

[0078] Example 1

[0079] The preparation method of the silicon-carbon negative electrode material based on the 3D-printed solid-state electrolyte skeleton of the present embodiment comprises:

[0080] (1) uniformly mix the solid-state electrolyte LPSCl, the binder NBR, and the solvent ethyl acetate according to a mass ratio of 80:5:50 to obtain a 3D printing slurry; 3D print the 3D printing slurry on one side surface of the current collector copper foil to obtain a 3D-printed solid-state electrolyte skeleton base material, which is vertically arranged on the surface of the current collector copper foil, and the 3D-printed solid-state electrolyte skeleton base material is a columnar array composed of a plurality of columnar solid-state electrolyte skeletons; wherein the diameter of a single columnar solid-state electrolyte skeleton is 5mm, the height is 60μm, and the gap (distance) between two adjacent columnar solid-state electrolyte skeletons is 2mm.

[0081] (2) place the 3D-printed solid-state electrolyte skeleton obtained in step (1) in a fluidized bed for chemical vapor deposition, introduce silane gas (monosilane), heat to 750℃, and deposit silicon particles with an average particle size of 100nm in the interstices and on the upper surface of the 3D-printed solid-state electrolyte skeleton base material; naturally cool to room temperature, replace the gas environment with acetylene gas, heat to 600℃, and deposit a carbon layer in the interstices and on the upper surface of the 3D-printed solid-state electrolyte skeleton base material on which the silicon particles are deposited, and the surface of the silicon particles is wrapped with a carbon layer, to obtain a 3D-printed solid-state electrolyte skeleton with silicon-carbon deposition; wherein the mass ratio of the 3D-printed solid-state electrolyte skeleton base material, the silicon particles, and the carbon layer is 40:50:10.

[0082] (3) Silicon nitride, adhesive NBR and solvent ethyl acetate were uniformly mixed according to a mass ratio of 85:5:50 to prepare an interfacial layer slurry, the interfacial layer slurry was coated on the surface of the 3D-printed solid electrolyte framework with silicon-carbon deposition obtained in step (2), and was dried to form an interfacial layer with an average thickness of 2 μm, thereby obtaining a silicon-carbon negative electrode material.

[0083] The silicon-carbon negative electrode material was die-cut to obtain a negative electrode sheet. Positive electrode active material NCM, conductive agent VGCF, adhesive NBR and solid electrolyte LPSCl were mixed according to a mass ratio of 70:2:5:23 to prepare a positive electrode sheet. Solid electrolyte LPSCl and adhesive PTFE were mixed according to a mass ratio of 95:5 to prepare a solid electrolyte sheet. The interfacial layer of the negative electrode sheet was connected to the solid electrolyte sheet, and then the positive electrode sheet was assembled together to obtain a solid-state battery.

[0084] The performance test results of the solid-state battery in this example are shown in Table 1.

[0085] Example 2

[0086] The preparation method of the silicon-carbon negative electrode material based on the 3D-printed solid electrolyte framework in this example comprises:

[0087] (1) According to step (1) of Example 1, the difference is that the diameter of the single columnar solid electrolyte framework in the 3D-printed solid electrolyte framework substrate is 5 mm, the height is 60 μm, and the gap size between two adjacent columnar solid electrolyte frameworks is 5 mm.

[0088] (2) The same as step (2) of Example 1.

[0089] (3) The same as step (3) of Example 1.

[0090] The silicon-carbon negative electrode material in this example was die-cut to obtain a negative electrode sheet, and the solid-state battery was assembled according to the steps in Example 1.

[0091] The performance test results of the solid-state battery in this example are shown in Table 1.

[0092] Example 3

[0093] The preparation method of the silicon-carbon negative electrode material based on the 3D-printed solid electrolyte framework in this example comprises:

[0094] (1) According to step (1) of Example 1, the difference is that the diameter of the single columnar solid electrolyte framework in the 3D-printed solid electrolyte framework substrate is 5 mm, the height is 60 μm, and the gap size between two adjacent columnar solid electrolyte frameworks is 5 mm.

[0095] (2) The same as step (2) of Example 1.

[0096] (3) The same as step (3) of Example 1.

[0097] The silicon-carbon negative electrode material in this example was die-cut into a negative electrode sheet, and a solid-state battery was assembled according to the steps in Example 1.

[0098] The performance test results of the solid-state battery in this example are shown in Table 1.

[0099] Example 4

[0100] The preparation method of the silicon-carbon negative electrode material based on a 3D-printed solid electrolyte skeleton in this example comprises:

[0101] (1) According to step (1) of Example 1, the difference is that the diameter of a single columnar solid electrolyte skeleton in the 3D-printed solid electrolyte skeleton substrate is 0.5 mm, the height is 60 μm, and the gap between two adjacent columnar solid electrolyte skeletons is 2 mm.

[0102] (2) The same as step (2) of Example 1.

[0103] (3) The same as step (3) of Example 1.

[0104] The silicon-carbon negative electrode material in this example was die-cut into a negative electrode sheet, and a solid-state battery was assembled according to the steps in Example 1.

[0105] The performance test results of the solid-state battery in this example are shown in Table 1.

[0106] Example 5

[0107] The preparation method of the silicon-carbon negative electrode material based on a 3D-printed solid electrolyte skeleton in this example comprises:

[0108] (1) According to step (1) of Example 1, the difference is that the diameter of a single columnar solid electrolyte skeleton in the 3D-printed solid electrolyte skeleton substrate is 0.5 mm, the height is 60 μm, and the gap between two adjacent columnar solid electrolyte skeletons is 2 mm.

[0109] (2) The same as step (2) of Example 1.

[0110] (3) The same as step (3) of Example 1.

[0111] The silicon-carbon negative electrode material in this example was die-cut into a negative electrode sheet, and a solid-state battery was assembled according to the steps in Example 1.

[0112] The performance test results of the solid-state battery in this example are shown in Table 1.

[0113] Example 6

[0114] The preparation method of the silicon-carbon negative electrode material based on the 3D-printed solid electrolyte framework in the embodiment comprises:

[0115] (1) The same as step (1) of Example 1.

[0116] (2) According to step (2) of Example 1, except that the mass ratio of the 3D-printed solid electrolyte framework substrate, silicon particles and carbon layer is 10:70:20.

[0117] (3) The same as step (3) of Example 1.

[0118] The silicon-carbon negative electrode material in the embodiment is die-cut to form a negative electrode sheet, and a solid-state battery is assembled according to the steps in Example 1.

[0119] The performance test results of the solid-state battery in the embodiment are shown in Table 1.

[0120] Example 7

[0121] The preparation method of the silicon-carbon negative electrode material based on the 3D-printed solid electrolyte framework in the embodiment comprises:

[0122] (1) The same as step (1) of Example 1.

[0123] (2) According to step (2) of Example 1, except that the mass ratio of the 3D-printed solid electrolyte framework substrate, silicon particles and carbon layer is 75:20:5.

[0124] (3) The same as step (3) of Example 1.

[0125] The silicon-carbon negative electrode material in the embodiment is die-cut to form a negative electrode sheet, and a solid-state battery is assembled according to the steps in Example 1.

[0126] The performance test results of the solid-state battery in the embodiment are shown in Table 1.

[0127] Example 8

[0128] The preparation method of the silicon-carbon negative electrode material based on the 3D-printed solid electrolyte framework in the embodiment comprises:

[0129] (1) The same as step (1) of Example 1.

[0130] (2) The same as step (2) of Example 1.

[0131] (3) According to step (3) of Example 1, except that the thickness of the interface layer is 1 μm.

[0132] The silicon-carbon negative electrode material in the embodiment is die-cut to form a negative electrode sheet, and a solid-state battery is assembled according to the steps in Example 1.

[0133] The performance test results of the solid-state battery in this example are shown in Table 1.

[0134] Example 9

[0135] The preparation method of the silicon-carbon negative electrode material based on the 3D-printed solid electrolyte framework in this example comprises:

[0136] (1) The same as step (1) of Example 1.

[0137] (2) The same as step (2) of Example 1.

[0138] (3) According to step (3) of Example 1, the difference is that the interface layer thickness is 10 μm.

[0139] The silicon-carbon negative electrode material in this example is die-cut into a negative electrode sheet, and a solid-state battery is assembled according to the steps in Example 1.

[0140] The performance test results of the solid-state battery in this example are shown in Table 1.

[0141] Example 10

[0142] The preparation method of the silicon-carbon negative electrode material based on the 3D-printed solid electrolyte framework in this example comprises:

[0143] (1) The same as step (1) of Example 1.

[0144] (2) The same as step (2) of Example 1.

[0145] (3) According to step (3) of Example 1, the difference is that silicon fluoride is used instead of silicon nitride.

[0146] The silicon-carbon negative electrode material in this example is die-cut into a negative electrode sheet, and a solid-state battery is assembled according to the steps in Example 1.

[0147] The performance test results of the solid-state battery in this example are shown in Table 1.

[0148] Example 11

[0149] The preparation method of the silicon-carbon negative electrode material based on the 3D-printed solid electrolyte framework in this example comprises:

[0150] (1) The same as step (1) of Example 1.

[0151] (2) The same as step (2) of Example 1.

[0152] (3) According to step (3) of Example 1, the difference is that boron nitride is used instead of silicon nitride.

[0153] The silicon-carbon negative electrode material in this example is die-cut into a negative electrode sheet, and a solid-state battery is assembled according to the steps in Example 1.

[0154] The performance test results of the solid-state battery in this example are shown in Table 1.

[0155] Example 12

[0156] The preparation method of the silicon-carbon negative electrode material based on the 3D-printed solid-state electrolyte skeleton in this example includes:

[0157] (1) According to step (1) of Example 1, the difference is that the height of the 3D-printed solid-state electrolyte skeleton matrix is 200 μm.

[0158] (2) The same as step (2) of Example 1.

[0159] (3) The same as step (3) of Example 1.

[0160] The silicon-carbon negative electrode material in this example is die-cut into a negative electrode sheet, and a solid-state battery is assembled according to the steps in Example 1.

[0161] The performance test results of the solid-state battery in this example are shown in Table 1.

[0162] Example 13

[0163] The preparation method of the silicon-carbon negative electrode material based on the 3D-printed solid-state electrolyte skeleton in this example includes:

[0164] (1) According to step (1) of Example 1, the difference is that the height of the 3D-printed solid-state electrolyte skeleton matrix is 10 μm.

[0165] (2) The same as step (2) of Example 1.

[0166] (3) The same as step (3) of Example 1.

[0167] The silicon-carbon negative electrode material in this example is die-cut into a negative electrode sheet, and a solid-state battery is assembled according to the steps in Example 1.

[0168] The performance test results of the solid-state battery in this example are shown in Table 1.

[0169] Comparative Example 1

[0170] The preparation method of the silicon-carbon negative electrode material in this comparative example includes:

[0171] Micron silicon (average particle size 3 μm), binder NBR, and solvent ethyl acetate are mixed in a mass ratio of 85:5:50 to prepare a negative electrode slurry. The negative electrode slurry is coated on a copper foil, dried, and a silicon-carbon negative electrode material is obtained.

[0172] The silicon-carbon negative electrode material in the present comparative example was die-cut to form a negative electrode sheet, and a solid-state battery was assembled according to the steps in Example 1.

[0173] The performance test results of the solid-state battery in the present comparative example are shown in Table 1.

[0174] Comparative Example 2

[0175] The preparation method of the silicon-carbon negative electrode material in the present comparative example comprises:

[0176] (1) The copper foil was placed in a fluidized bed, silane gas was introduced, and heated to 750°C to deposit silicon particles with an average particle size of 100 nm on the surface of the copper foil; after natural cooling, the gas environment was replaced with acetylene gas, and heated to 600°C to deposit a carbon layer on the surface of the silicon particles to obtain a silicon-carbon deposited copper foil; wherein the mass ratio of the silicon particles to the carbon layer is 50:10.

[0177] (2) Silicon nitride, binder NBR, and solvent ethyl acetate were mixed according to a mass ratio of 85:5:50 to prepare an interface layer slurry, the interface layer slurry was coated on the surface of the silicon-carbon deposited copper foil obtained in step (1), and dried to form an interface layer with an average thickness of 2 μm, thereby obtaining a silicon-carbon negative electrode material.

[0178] The silicon-carbon negative electrode material in the present comparative example was die-cut to form a negative electrode sheet, and a solid-state battery was assembled according to the steps in Example 1.

[0179] The performance test results of the solid-state battery in the present comparative example are shown in Table 1.

[0180] Comparative Example 3

[0181] The preparation method of the silicon-carbon negative electrode material in the present comparative example comprises:

[0182] (1) According to step (1) of Example 1, the difference is that the current collector copper foil is replaced with a silicon nitride layer prepared using the interface layer slurry in Example 1.

[0183] (2) The same as step (2) of Example 1.

[0184] (3) The same as step (3) of Example 1.

[0185] The silicon-carbon negative electrode material in the present comparative example was die-cut to form a negative electrode sheet, and a solid-state battery was assembled according to the steps in Example 1.

[0186] In the present comparative example, the current collector was replaced with a silicon nitride layer, which is not conductive, resulting in that the solid-state battery cannot be normally charged and discharged.

[0187] Comparative Example 4

[0188] The preparation method of the silicon-carbon negative electrode material in the present comparative example comprises:

[0189] (1) The same as step (1) of Example 1.

[0190] (2) The same as step (2) of Example 1.

[0191] (3) The copper foil is directly covered on the surface of the silicon-carbon deposited 3D printed solid electrolyte skeleton, that is, the copper foil is on both sides of the 3D printed solid electrolyte skeleton substrate, to obtain a silicon-carbon negative electrode material.

[0192] The silicon-carbon negative electrode material in the present comparative example is made into a negative electrode sheet, and a solid-state battery is assembled according to the steps in Example 1.

[0193] The performance test results of the solid-state battery in the present comparative example are shown in Table 1.

[0194] Comparative Example 5

[0195] The preparation method of the silicon-carbon negative electrode material in the present comparative example comprises:

[0196] (1) The same as step (1) of Example 1.

[0197] (2) According to step (2) of Example 1, the difference is that the carbon layer is first deposited by passing in acetylene gas, and then replaced with silane gas (monosilane) to generate silicon particles.

[0198] (3) The same as step (3) of Example 1.

[0199] The silicon-carbon negative electrode material in the present comparative example is made into a negative electrode sheet, and a solid-state battery is assembled according to the steps in Example 1.

[0200] The performance test results of the solid-state battery in the present comparative example are shown in Table 1.

[0201] Table 1, performance test results of performance test of solid-state battery

[0202]

[0203] According to the above table, the silicon-carbon negative electrode material based on the 3D printed solid electrolyte skeleton of the present application is a three-layer structure comprising a current collector, a 3D printed solid electrolyte skeleton, and an interface layer in sequence; wherein the 3D printed solid electrolyte skeleton comprises a 3D printed solid electrolyte skeleton matrix and silicon particles and a carbon layer deposited in the voids and on the surface of the skeleton matrix in sequence; the present application adjusts the proportion of the 3D printed solid electrolyte skeleton matrix, silicon particles and carbon layer by controlling the size of the 3D printed solid electrolyte skeleton substrate, deposition parameters, etc., so that the silicon-carbon negative electrode material based on the 3D printed solid electrolyte skeleton exhibits better performance in solid-state batteries. The present application uses nitrogen-containing materials and / or fluorine-containing materials as interface layer raw materials, which synergistically act with the current collector on the other side of the 3D printed solid electrolyte skeleton to improve the performance of the solid-state battery.

[0204] In summary, the application utilizes 3D printing technology to precisely construct a solid-state electrolyte three-dimensional skeleton matrix, which provides a customizable constraint space for silicon expansion, fundamentally inhibiting structural failure caused by volume change; at the same time, a continuous ion conduction network is formed, greatly improving ion transport efficiency; chemical vapor deposition process is adopted to sequentially deposit nano-silicon particles and carbon layers in situ, realizing high loading and uniform distribution of silicon and depositing carbon layers to construct a stable electronic conduction network, ensuring capacity and reaction kinetics; finally, by introducing an interface protection layer, Li3N or LiF with high ion conductivity is generated in situ, significantly enhancing the interface stability, effectively inhibiting side reactions and guiding uniform deposition of lithium ions, thereby greatly improving the cycle life and safety performance of the battery. The scheme of the application integrates active materials, ion / electron conductors and stable interfaces in situ, providing an extremely promising solution for the development of high-energy-density, long-life all-solid-state batteries.

[0205] Aspects, embodiments, features of the application are to be considered illustrative only and not restrictive in all aspects. The scope of the application is defined only by the claims. Other embodiments, modifications and uses will be apparent to those skilled in the art without departing from the spirit and scope of the claimed application.

[0206] In the preparation method of the application, the order of the steps is not limited to the order listed, and for those skilled in the art, changes in the order of the steps without creative labor are within the protection scope of the application. In addition, two or more steps or actions can be carried out simultaneously.

[0207] Finally, it should be noted that the specific embodiments described herein are merely illustrative of the application and are not intended to limit the embodiments of the application. Those skilled in the art can make various modifications or supplements to the described specific embodiments or use similar ways to replace them. Here, it is not necessary or possible to fully exemplify all embodiments. However, these obvious changes or variations within the spirit of the application still fall within the protection scope of the application, and any additional limitation is contrary to the spirit of the application.

Claims

1. A silicon-carbon anode material based on a 3D-printed solid electrolyte framework, characterized in that, It has a three-layer structure, which includes a current collector, a 3D printed solid electrolyte framework, and an interface layer. The 3D printed solid electrolyte framework includes a 3D printed solid electrolyte framework matrix and silicon particles and a carbon layer deposited sequentially in the voids and on the surface of the framework matrix. The interface layer includes nitrogen-containing materials and / or fluorine-containing materials. The silicon particles are amorphous silicon; The 3D printed solid electrolyte skeleton matrix has a columnar structure, which is a columnar array composed of multiple columnar solid electrolyte skeletons. The diameter of a single columnar solid electrolyte skeleton is 0.1~10mm, and the gap between two adjacent columnar solid electrolyte skeletons is 2~10mm.

2. The silicon-carbon anode material based on a 3D-printed solid electrolyte framework according to claim 1, characterized in that, The mass ratio of the 3D printed solid electrolyte skeleton matrix, silicon particles, and carbon layer in the 3D printed solid electrolyte skeleton is (10~75):(20~70):(5~20).

3. The silicon-carbon anode material based on a 3D-printed solid electrolyte framework according to claim 2, characterized in that, In the 3D printed solid electrolyte framework, the mass of silicon particles > the mass of the 3D printed solid electrolyte framework matrix > the mass of the carbon layer.

4. The silicon-carbon anode material based on a 3D-printed solid electrolyte framework according to claim 1, characterized in that, The distance between the current collector and the interface layer is 10~200μm.

5. The silicon-carbon anode material based on a 3D-printed solid electrolyte framework according to claim 1, characterized in that, The thickness of the interface layer is 0.1~20μm.

6. The silicon-carbon anode material based on a 3D-printed solid electrolyte framework according to claim 1, characterized in that, The nitrogen-containing material includes one or more of silicon nitride, boron nitride, lithium nitride, magnesium nitride, aluminum nitride, titanium nitride, and tantalum nitride; the fluorine-containing material includes one or more of silicon fluoride, lithium fluoride, magnesium fluoride, aluminum fluoride, titanium fluoride, and tantalum fluoride.

7. The silicon-carbon anode material based on a 3D-printed solid electrolyte framework according to claim 1, characterized in that, The particle size of the silicon particles is 0.001 to 80% of the voids in the 3D printed solid electrolyte framework matrix.

8. The silicon-carbon anode material based on a 3D-printed solid electrolyte framework according to claim 1, characterized in that, The method for preparing the 3D-printed solid electrolyte framework includes: placing the 3D-printed solid electrolyte framework substrate in a silane gas environment, depositing silicon particles in its pores and surface through a chemical vapor deposition process, changing the gas environment to a carbon source gas, and depositing a carbon layer; the silane gas includes one or more of methanesilane, dichlorosilane, trichlorosilane, silicon tetrachloride, and hexachlorosilane; the carbon source gas includes one or more of acetylene, methane, ethylene, propane, and propylene.

9. A method for preparing a silicon-carbon anode material based on a 3D-printed solid electrolyte framework as described in claim 1, characterized in that, The preparation method includes: 3D printing a 3D printed solid electrolyte framework substrate by applying a 3D printing slurry to one side surface of the current collector; placing the 3D printed solid electrolyte framework substrate in a silane gas environment and depositing silicon particles in its voids and surface by chemical vapor deposition; changing the gas environment to a carbon source gas and depositing a carbon layer to obtain a 3D printed solid electrolyte framework; and coating an interface layer slurry on the side of the 3D printed solid electrolyte framework away from the current collector to form an interface layer.

10. The method for preparing silicon-carbon anode material based on a 3D-printed solid electrolyte framework according to claim 9, characterized in that, The method for preparing the interface layer includes: preparing an interface layer slurry by mixing nitrogen-containing materials and / or fluorine-containing materials, binders, and solvents in a mass ratio of (80~95):(1~10):(1~80), coating it on the surface of the 3D printed solid electrolyte skeleton away from the current collector, and drying it to form the interface layer.

11. A solid-state battery, characterized in that, The material includes a negative electrode sheet, wherein the negative electrode sheet comprises a silicon-carbon negative electrode material based on a 3D-printed solid electrolyte framework as described in any one of claims 1 to 8, or a silicon-carbon negative electrode material based on a 3D-printed solid electrolyte framework prepared by the preparation method of the silicon-carbon negative electrode material based on a 3D-printed solid electrolyte framework as described in any one of claims 9 to 10.

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