Silicon-based composite negative electrode material and preparation method thereof and all-solid-state lithium battery

Abstract

The present application provides a silicon-based composite negative electrode material, the silicon-based composite negative electrode material comprising a silicon-based material core, and an antiperovskite solid electrolyte layer and a sulfur-based solid electrolyte layer sequentially covering the silicon-based material core, the antiperovskite solid electrolyte layer comprising Li 3‑t OH t A, wherein A is at least one of Cl, Br and I, and 0≤t≤2. The silicon-based composite negative electrode material has low impedance, high ion conductivity and outstanding electrochemical performance. The application also provides a preparation method of the silicon-based composite negative electrode material and an all-solid-state lithium battery.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a silicon-based composite negative electrode material and a preparation method thereof and an all-solid-state lithium battery. Background Art

[0002] In recent years, all-solid-state lithium batteries using solid electrolytes have received widespread attention due to their high safety. Among them, the silicon negative electrode with high theoretical specific capacity and high safety is considered to be an effective way to break through the energy density of all-solid-state lithium batteries. However, the ionic and electronic conductivity of the silicon negative electrode is poor, and it is usually necessary to modify its surface or add a large amount of additives such as solid electrolytes and conductive agents to assist. Additives that are not electrochemically active reduce the performance of the silicon negative electrode capacity and the specific energy of the all-solid-state lithium battery, restricting the application of all-solid-state lithium batteries. Summary of the invention

[0003] In view of this, the present application provides a silicon-based composite negative electrode material and a preparation method thereof, a negative electrode and an all-solid-state lithium battery. The silicon-based composite negative electrode material has low impedance, high ionic conductivity, and outstanding electrochemical performance. The battery made from the silicon-based composite negative electrode material has high capacity and good cycle performance, which is conducive to its application.

[0004] In a first aspect, the present application provides a silicon-based composite negative electrode material, the silicon-based composite negative electrode material comprising a silicon-based material core, and an antiperovskite solid electrolyte layer and a sulfur-based solid electrolyte layer sequentially covering the silicon-based material core, the antiperovskite solid electrolyte layer comprising Li 3-t OH t A, wherein A is at least one of Cl, Br and I, 0≤t≤2.

[0005] Optionally, the thickness of the sulfide solid electrolyte layer is greater than the thickness of the antiperovskite solid electrolyte layer.

[0006] Optionally, the thickness ratio of the antiperovskite solid electrolyte layer to the sulfur-based solid electrolyte layer is 1:(2-100).

[0007] Optionally, the antiperovskite solid electrolyte layer has a thickness of 5 nm-200 nm.

[0008] Optionally, the thickness of the sulfur-based solid electrolyte layer is 20 nm-3 μm.

[0009] Optionally, the particle size of the silicon-based material core is 10 nm-1 μm.

[0010] Optionally, the silicon-based material core includes at least one of elemental silicon material, silicon alloy material, silicon-oxygen material and silicon-carbon material.

[0011] Furthermore, the silicon alloy material includes lithium silicon alloy Li x Si, 0<x≤4.4.

[0012] Furthermore, the silicon-oxygen material includes silicon oxide SiO y , 0<y<2.

[0013] Optionally, the sulfur-based solid electrolyte layer includes glassy mLi2S·nP2S5 and crystalline Li a P b S c At least one of the following, wherein m+n=100, m>n, a, b and c are positive integers greater than zero, a+5b=2c, 1≤a / b<4.

[0014] In the silicon-based composite negative electrode material provided in the first aspect of the present application, the antiperovskite solid electrolyte layer and the sulfur-based solid electrolyte layer can provide an ion conductive network for the silicon-based material core, greatly improving the ionic conductivity of the silicon-based composite negative electrode material. At the same time, the antiperovskite solid electrolyte layer has the characteristics of conducting ions but not conducting electrons, thereby reducing the surface voltage of the silicon-based material core and ensuring that the sulfur-based solid electrolyte layer is not decomposed, thereby avoiding the problem of increased impedance caused by the decomposition of the sulfur-based solid electrolyte layer, which is beneficial to reducing the interface impedance and improving the electrochemical performance of the silicon-based composite negative electrode material.

[0015] In a second aspect, the present application also provides a method for preparing a silicon-based composite negative electrode material, comprising:

[0016] The silicon-based material is coated with an antiperovskite solid electrolyte material to obtain a first coating, wherein the antiperovskite solid electrolyte material includes Li 3-t OH t A, wherein A is at least one of Cl, Br and I, 0≤t≤2;

[0017] The first coating is coated with a sulfur-based solid electrolyte to obtain a silicon-based composite negative electrode material.

[0018] Optionally, the preparation method further includes: mixing and ball-milling the silicon-based material and the antiperovskite solid electrolyte material to obtain the first coating; and mixing and ball-milling the first coating and the sulfur-based solid electrolyte material to obtain the silicon-based composite negative electrode material.

[0019] The preparation method of the silicon-based composite negative electrode material provided in the second aspect of the present application is simple, easy to operate, suitable for industrial production, and is conducive to the application of the silicon-based composite negative electrode material.

[0020] In the third aspect, the present application also provides an all-solid-state lithium battery, comprising a positive electrode, a negative electrode, and a solid electrolyte layer located between the positive electrode and the negative electrode, wherein the negative electrode comprises the silicon-based composite negative electrode material as described in the first aspect or the silicon-based composite negative electrode material prepared by the preparation method described in the second aspect.

[0021] Optionally, the negative electrode includes a negative electrode current collector and a negative electrode material layer disposed on the negative electrode current collector, the negative electrode material layer includes the silicon-based composite negative electrode material, and the negative electrode material layer does not contain a solid electrolyte material.

[0022] The all-solid-state lithium battery provided in the third aspect of the present application has high battery capacity and good cycle performance, which is conducive to its application. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the implementation modes of the present application, the drawings required for use in the implementation modes of the present application will be described below.

[0024] Figure 1 A schematic diagram of the structure of a silicon-based composite negative electrode material provided in one embodiment of the present application.

[0025] Figure 2 A schematic flow chart of a method for preparing a silicon-based composite negative electrode material provided in one embodiment of the present application.

[0026] Figure 3 A schematic diagram of the structure of an all-solid-state lithium battery provided in one embodiment of the present application.

[0027] Description of labels:

[0028] Silicon-based material core-11, antiperovskite solid electrolyte layer-12, sulfur-based solid electrolyte layer-13, silicon-based composite negative electrode material-10, negative electrode material layer-101, negative electrode current collector-102, negative electrode-100, positive electrode material layer-201, positive electrode current collector-202, positive electrode-200, solid electrolyte layer-300. DETAILED DESCRIPTION

[0029] The following are preferred implementations of the present application. It should be noted that, for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application, and these improvements and modifications are also considered to be within the scope of protection of the present application.

[0030] The disclosure below provides many different embodiments or examples to realize the different structures of the present application. In order to simplify the disclosure of the present application, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the various specific processes and material examples provided by the present application, but those of ordinary skill in the art can appreciate the application of other processes and / or the use of other materials.

[0031] See also Figure 1 , is a schematic structural diagram of a silicon-based composite negative electrode material provided in one embodiment of the present application, wherein the silicon-based composite negative electrode material 10 comprises a silicon-based material core 11, and an antiperovskite solid electrolyte layer 12 and a sulfur-based solid electrolyte layer 13 which sequentially cover the silicon-based material core 11, wherein the antiperovskite solid electrolyte layer 12 comprises Li 3-t OH t A, wherein A is at least one of Cl, Br and I, 0≤t≤2.

[0032] In the present application, the antiperovskite solid electrolyte layer 12 and the sulfur-based solid electrolyte layer 13 in the silicon-based composite negative electrode material 10 can provide an ion conductive network for the silicon-based material core 11. The two electrolyte layers work synergistically to greatly improve the ionic conductivity of the silicon-based composite negative electrode material 10, effectively avoiding the problem that lithium ions cannot escape from the silicon-based material core 11 during charging and discharging, accelerating the transmission rate of lithium ions in the silicon-based material core 11, improving the Coulomb efficiency of the lithium-ion battery, and improving the charging and discharging performance; and the silicon-based composite negative electrode material 10 with a core-shell structure effectively alleviates the volume expansion of the silicon-based material core 11, The cycle stability of the silicon-based composite negative electrode material 10 is improved; at the same time, the setting of the sulfur-based solid electrolyte layer 13 can take into account the ionic conductivity and low voltage conditions of the silicon-based composite negative electrode material 10; since the sulfur-based solid electrolyte layer 13 will decompose under low voltage, resulting in a continuous increase in impedance, and then by setting an anti-perovskite solid electrolyte layer 12 that conducts ions but does not conduct electrons, the chemical potential difference of lithium ions is guaranteed while effectively reducing the surface voltage of the silicon-based material core 11, which can effectively avoid the decomposition of the sulfur-based solid electrolyte layer 13, which is beneficial to reducing the interface impedance and improving the electrochemical performance of the silicon-based composite negative electrode material 10.

[0033] In the present application, the silicon-based material core 11 is a core of a silicon-containing material; the silicon-containing material is a negative electrode material with an ultra-high specific capacity. In the embodiment of the present application, the silicon-based material core 11 includes at least one of a single silicon material, a silicon alloy material, a silicon-oxygen material, and a silicon-carbon material.

[0034] In one embodiment of the present application, the silicon-based material core 11 includes nanoscale elemental silicon. By selecting nanoscale elemental silicon materials, the electrochemical activity of lithium ion insertion and extraction can be improved, and the volume change of the silicon-based material core 11 can be effectively alleviated. Specifically, the nanoscale elemental silicon can be, but is not limited to, at least one of silicon nanospheres, silicon nanotubes, and silicon nanowires. In another embodiment of the present application, the silicon-based material core 11 includes a silicon alloy material. Specifically, the silicon alloy material can include, but is not limited to, ferrosilicon alloys, silicon-copper alloys, silicon-aluminum alloys, and silicon-lithium alloys. Silicon can form silicon alloys with metal elements, so that the volume change of the silicon-based material core 11 is reduced, the cycle stability performance is improved, and the silicon alloy has a higher electrical conductivity, which is beneficial to improving the electrochemical performance. In one embodiment, the silicon alloy material includes a lithium silicon alloy Li x Si, 0<x≤4.4. Lithium silicon alloys with higher electronic conductivity and ionic conductivity can be charged and discharged more efficiently, and improve rate performance and cycle stability. Further, x is 2<x≤4.4. Specifically, lithium silicon alloys may include Li 1.71 Si, Li 2.33 Si、Li 3.25 Si, Li 3.75 Si、Li 4.4 In one embodiment, the lithium silicon alloy is Li 4.4 Si alloy. Li 4.4 Si alloy has a large amount of lithium insertion and a high capacity. Furthermore, the lithium silicon alloy may include one or more lattices. For example, the lattice in the lithium silicon alloy may include at least one of tetragonal system, orthorhombic system, rhombohedral system, orthorhombic system, body-centered cubic system and face-centered cubic system. In another embodiment of the present application, the silicon-based material core 11 includes silicon oxide material. The silicon oxide material has a small volume change and alleviates volume expansion. In one embodiment, the silicon oxide material includes silicon oxide SiO y , 0<y<2. In the embodiment of the present application, the material of the silicon-based material core 11 includes silicon-carbon material. It can ensure the high specific capacity of the silicon-based material core 11, and at the same time, the volume expansion of the silicon-based material core 11 made of silicon-carbon composite is relatively small, thereby ensuring the structural stability of the silicon-based composite negative electrode material 10.

[0035] In the embodiment of the present application, the weight proportion of the silicon-based material core 11 in the silicon-based composite negative electrode material 10 is 65wt%-90wt%. Further, the weight proportion of the silicon-based material core 11 in the silicon-based composite negative electrode material 10 is 70wt%-85wt%. Further, the weight proportion of the silicon-based material core 11 in the silicon-based composite negative electrode material 10 is 72wt%-83wt%. Specifically, the weight proportion of the silicon-based material core 11 in the silicon-based composite negative electrode material 10 can be, but not limited to, 68wt%, 70wt%, 73wt%, 75wt%, 80wt%, 85wt%, 87wt% or 90wt%, etc. The use of the silicon-based material core 11 with the above weight proportion ensures the specific capacity of the silicon-based composite negative electrode material 10, which is conducive to its application in all-solid-state lithium batteries.

[0036] In the present application, the shape of the silicon-based material core 11 is not limited, and specifically can be but not limited to spherical, quasi-spherical, etc. In the embodiment of the present application, the particle size of the silicon-based material core 11 is 10nm-1μm. Further, the particle size of the silicon-based material core 11 is 20nm-900nm. Furthermore, the particle size of the silicon-based material core 11 is 80nm-850nm. Specifically, the particle size of the silicon-based material core 11 can be but not limited to 10nm, 50nm, 100nm, 250nm, 300nm, 500nm, 650nm, 700nm, 800nm ​​or 900nm, etc. The silicon-based material core 11 with the above-mentioned particle size can improve the first cycle lithium insertion capacity of the silicon-based composite negative electrode material 10.

[0037] In the present application, the antiperovskite solid electrolyte layer 12 is arranged between the silicon-based material core 11 and the sulfur-based solid electrolyte layer 13. The antiperovskite solid electrolyte layer 12 has ion conductivity and electronic insulation, thereby providing an ion conductive network for the silicon-based material core 11 and improving the ion conductivity. At the same time, it can also effectively reduce the surface voltage of the silicon-based material core 11 and effectively avoid the decomposition of the sulfur-based solid electrolyte layer 13, which is beneficial to reduce the interface impedance and improve the electrochemical performance of the silicon-based composite negative electrode material 10.

[0038] In the present application, the antiperovskite solid electrolyte layer 12 includes Li 3-t OH t A, wherein A is at least one of Cl, Br and I, 0≤t≤2; when A is two or more elements, the ratio between the multiple elements is not limited. Specifically, the material of the antiperovskite solid electrolyte layer 12 can be but is not limited to LiOCl, Li2OHBr, Li2OHCl 0.2 Br 0.8 , Li 1.5 OH 1.5 Cl 0.7 I 0.3wait.

[0039] In an embodiment of the present application, the thickness of the antiperovskite solid electrolyte layer 12 is 5nm-200nm. Further, the thickness of the antiperovskite solid electrolyte layer 12 is 5nm-200nm. Further, the thickness of the antiperovskite solid electrolyte layer 12 is 5nm-200nm. Specifically, the thickness of the antiperovskite solid electrolyte layer 12 can be but is not limited to 5nm, 10nm, 20nm, 50nm, 80nm, 100nm, 130nm, 150nm or 180nm, etc. The antiperovskite solid electrolyte layer 12 with thickness is conducive to better protection of the sulfur-based solid electrolyte layer 13.

[0040] In the present application, a sulfur-based solid electrolyte layer 13 is used in the silicon-based composite negative electrode material 10, which can meet the conditions of good ionic conductivity and low voltage compatibility, strengthen the ionic conductivity of the silicon-based material core 11, and improve the electrochemical performance of the silicon-based composite negative electrode material 10.

[0041] In the embodiment of the present application, the sulfur-based solid electrolyte layer 13 includes glassy mLi2S·nP2S5 and crystalline Li a P b S c At least one of, wherein m+n=100, m>n, a, b and c are positive integers greater than zero, a+5b=2c, 1≤a / b<4. Specifically, the glassy mLi2S·nP2S5 includes at least one of glassy 70Li2S-30P2S5, 75Li2S-25P2S5 and 80Li2S-20P2S5; the crystalline Li a P b S c Including crystalline Li3PS4, Li7P3S 11 The use of the above materials can make the sulfur-based solid electrolyte layer 13 provide a better ion conductive network and improve the electrochemical performance of the silicon-based composite negative electrode material 10.

[0042] In an embodiment of the present application, the thickness of the sulfur-based solid electrolyte layer 13 is 20nm-3μm. Further, the thickness of the sulfur-based solid electrolyte layer 13 is 20nm-3μm. Further, the thickness of the sulfur-based solid electrolyte layer 13 is 20nm-3μm. Specifically, the thickness of the antiperovskite solid electrolyte layer 12 can be but is not limited to 5nm, 10nm, 20nm, 50nm, 80nm, 100nm, 130nm, 150nm or 180nm, etc. The sulfur-based solid electrolyte layer 13 with thickness is conducive to better improving the ionic conductivity of the silicon-based composite negative electrode material 10.

[0043] In the present application, the antiperovskite solid electrolyte layer 12 and the sulfur-based solid electrolyte layer 13 work synergistically to greatly improve the ionic conductivity of the silicon-based composite negative electrode material 10, accelerate the lithium ion transmission rate, and improve the charge and discharge performance. At the same time, the antiperovskite solid electrolyte layer 12 protects the sulfur-based solid electrolyte layer 13, prevents the decomposition of the sulfur-based solid electrolyte layer 13, effectively reduces the impedance of the silicon-based composite negative electrode material 10, and improves the electrochemical performance.

[0044] In an embodiment of the present application, the thickness of the sulfur-based solid electrolyte layer 13 is greater than the thickness of the antiperovskite solid electrolyte layer 12. This is more conducive to the antiperovskite solid electrolyte layer 12 protecting the sulfur-based solid electrolyte layer 13 from decomposition. In an embodiment of the present application, the thickness ratio of the antiperovskite solid electrolyte layer 12 and the sulfur-based solid electrolyte layer 13 is 1: (2-100). Further, the thickness ratio of the antiperovskite solid electrolyte layer 12 and the sulfur-based solid electrolyte layer 13 is 1: (5-95). Further, the thickness ratio of the antiperovskite solid electrolyte layer 12 and the sulfur-based solid electrolyte layer 13 is 1: (10-80). Specifically, the thickness ratio of the antiperovskite solid electrolyte layer 12 and the sulfur-based solid electrolyte layer 13 can be, but is not limited to, 1: (2-100), 1: (10-80), 1: (15-80), 1: (20-80), 1: (30-75) or 1: (40-65) and the like. Thereby, the antiperovskite solid electrolyte layer 12 can better protect the sulfur-based solid electrolyte layer 13 from being decomposed, and at the same time ensure the ion conduction of the sulfur-based solid electrolyte layer 13 , that is, lithium ions can be smoothly transmitted through the sulfur-based solid electrolyte layer 13 to form a network.

[0045] See also Figure 2 , is a schematic flow chart of a method for preparing a silicon-based composite negative electrode material provided in one embodiment of the present application, comprising:

[0046] S101: The silicon-based material is coated with an antiperovskite solid electrolyte material to obtain a first coating, wherein the antiperovskite solid electrolyte material includes Li 3-t OH t A, wherein A is at least one of Cl, Br and I, 0≤t≤2.

[0047] S102: The first coating is coated with a sulfur-based solid electrolyte to obtain a silicon-based composite negative electrode material.

[0048] In the embodiment of the present application, the preparation of the silicon-based composite negative electrode material 10 is carried out under a protective gas. Specifically, the protective gas includes at least one of nitrogen, helium, hydrogen, and the like.

[0049] In an embodiment of the present application, the coating can be performed by a ball mill or a solid-solid coating device. In an embodiment of the present application, the ball milling method can be wet ball milling or dry ball milling. Specifically, the solvent in the wet ball milling can be but is not limited to at least one selected from toluene, xylene, anisole, heptane, decane, ethyl acetate, ethyl propionate, butyl butyrate, N-methylpyrrolidone and acetone.

[0050] In one embodiment of the present application, the silicon-based material and the antiperovskite solid electrolyte material are mixed and ball-milled to obtain a first coating. That is, the first coating includes a silicon-based material and an antiperovskite solid electrolyte material coating the silicon-based material. Further, the ball milling speed is 50rpm-250rpm, and the time is 5min-30min. In another embodiment of the present application, the silicon-based material and the antiperovskite solid electrolyte material are placed in a solid-solid coating device and mixed to obtain a first coating. Further, the speed of the solid-solid coating device is 1000rpm-8000rpm, and the time is 3min-10min. In another embodiment of the present application, the temperature is raised to 250℃-400℃ at a rate exceeding 10℃ / min, and the first coating is kept warm for 10min-60min. Ensure the tightness of the coating. Specifically, it can be, but not limited to, the temperature is raised to 300℃ at a rate exceeding 10℃ / min, and the first coating is kept warm for 30min.

[0051] In one embodiment of the present application, the first coating is mixed with the sulfur-based solid electrolyte material and ball-milled to obtain a silicon-based composite negative electrode material 10. That is, the silicon-based composite negative electrode material 10 includes a first coating and a sulfur-based solid electrolyte material coating the first coating. Further, the ball milling speed is 50rpm-250rpm, and the time is 5min-30min. In another embodiment of the present application, the first coating and the sulfur-based solid electrolyte material are placed in a solid-solid coating device and mixed to obtain a silicon-based composite negative electrode material 10. Further, the solid-solid coating device has a speed of 1000rpm-8000rpm, and the time is 3min-10min.

[0052] The relevant parameters and functions of the silicon-based composite negative electrode material 10 prepared by the preparation method of the present application are as described above and will not be repeated here.

[0053] The preparation method of the silicon-based composite negative electrode material 10 provided in the present application is simple, easy to operate, suitable for industrial production, and is conducive to the application of the silicon-based composite negative electrode material 10.

[0054] See also Figure 3, is a schematic structural diagram of an all-solid-state lithium battery provided in one embodiment of the present application, the all-solid-state lithium battery includes a positive electrode 200, a negative electrode 100 and a solid electrolyte layer 300 located between the positive electrode 200 and the negative electrode 100, and the negative electrode 100 includes the silicon-based composite negative electrode material 10 in any of the above embodiments.

[0055] In the embodiment of the present application, the negative electrode 100 includes a negative electrode current collector 102 and a negative electrode material layer 101 disposed on the negative electrode current collector 102, and the negative electrode material layer 101 includes a silicon-based composite negative electrode material 10. Specifically, the thickness of the negative electrode material layer 101 may be, but is not limited to, 5 μm-50 μm.

[0056] In the embodiment of the present application, the negative electrode material layer 101 does not contain a solid electrolyte material. In this way, the negative electrode material layer 101 can include a silicon-based composite negative electrode material 10 with a large content and electrochemical activity, thereby making the capacity of the negative electrode 100 larger and the energy density of the all-solid-state lithium battery higher.

[0057] In an embodiment of the present application, the negative electrode material layer 101 further includes at least one of a conductive agent and a binder. Among them, the binder helps to firmly fix the negative electrode material layer 101 on the negative electrode current collector 102 and make the negative electrode material layer 101 have a certain elasticity; the conductive agent helps to improve the conductivity of the negative electrode material layer 101. In one embodiment of the present application, the binder may include but is not limited to polythiophene, polypyrrole, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polystyrene, polyacrylamide, ethylene-propylene-diene copolymer resin, styrene butadiene rubber, polybutadiene, fluororubber, polyvinyl pyrrolidone, polyester resin, acrylic resin, phenolic resin, epoxy resin, polyvinyl alcohol, carboxypropyl cellulose, ethyl cellulose, polyethylene oxide, sodium carboxymethyl cellulose and styrene butadiene rubber. In another embodiment of the present application, the mass percentage of the binder in the negative electrode material layer 101 is 0.5%-5%. Specifically, the mass percentage of the binder in the negative electrode material layer 101 may be, but is not limited to, 1%-5%, 1.5%-4.5%, 2%-4% or 2.5%-3.8%, etc. In another embodiment of the present application, the conductive agent may include, but is not limited to, at least one of acetylene black, carbon nanowires, graphite and graphene. In another embodiment of the present application, the mass percentage of the conductive agent in the negative electrode material layer 101 is 0.1%-10%. Specifically, the mass percentage of the conductive agent in the negative electrode material layer 101 may be, but is not limited to, 0.3%-9%, 0.7%-8%, 1%-7% or 1.5%-5%, etc.

[0058] In the embodiment of the present application, the positive electrode 200 may include a positive electrode current collector 202 and a positive electrode material layer 201 disposed on the positive electrode current collector 202. The positive electrode material layer 201 may include a positive electrode active material, a conductive agent, a positive electrode solid electrolyte material, and a positive electrode binder.

[0059] In the embodiment of the present application, the positive electrode active material includes one or more of oxide type, sulfide type, polyanion type and composites of the above materials. In one embodiment of the present application, the oxide type positive electrode active material may include but is not limited to TiO2, Cr3O8, V2O5, MnO2, NiO, WO3, LiMn2O4, Li2CuO2, LiCo m1 Ni 1-m1 O2(0≤m1≤1), LiCo a1 Ni 1-a1-b1 Al b1 O2 (0≤a1≤1, 0≤b1≤1), LiFe c1 Mn d G e O4 (G is selected from at least one of Al, Mg, Ga, Cr, Co, Ni, Cu, Zn and Mo, 0≤c1≤1, 0≤d≤1, 0≤e≤1, c1+d+e=1), Li 1+f L 1－g－h H g R h O2 (L, H and R are independently selected from at least one of Li, Co, Mn, Ni, Fe, Al, Mg, Ga, Ti, Cr, Cu, Zn, Mo, F, I, S and B, and L, H and R are different elements, and -0.1≤f≤0.2, 0≤g≤1, 0≤h≤1, 0≤g+h≤1) etc. Specifically, the oxide-type positive electrode active material may be, but is not limited to, one or more of LiCoO2, LiNiO2, LiMn2O4. In another embodiment of the present application, the sulfide-type positive electrode active material may include TiS2, V2S3, FeS, FeS2, WS2, LiJS i (J is selected from at least one of Ti, Fe, Ni, Cu and Mo, 1≤i≤2.5), etc. In another embodiment of the present application, the polyanionic positive electrode active material may specifically include at least one of LiFePO4, Li3V2(PO4)3, Li3V3(PO4)3 and LiVPO4F.

[0060] In the embodiment of the present application, the particle size of the positive electrode active material is 100 nm-500 μm. Specifically, the particle size of the positive electrode active material may be, but is not limited to, 100 nm-100 μm, 100 nm-50 μm or 500 nm-50 μm.

[0061] In the embodiment of the present application, the surface of the positive electrode active material may also have a coating layer to optimize the interface between the positive electrode material layer 201 and the solid electrolyte, reduce the interface impedance, and improve the cycle stability. Specifically, the coating layer on the surface of the positive electrode active material may be LiNbO3, LiTaO3, Li3PO4, Li4Ti5O 12 wait.

[0062] In the present application, there is no particular restriction on the positive electrode binder in the positive electrode material layer 201, and its material can be selected from the binder in the above-mentioned negative electrode material layer 101. For example, it can be at least one of fluorine-containing resin, polyvinylidene fluoride, polytetrafluoroethylene, polyvinyl alcohol, polyolefin, styrene-butadiene rubber, etc. There is no particular restriction on the conductive agent in the positive electrode material layer 201, and conventional materials available in the art can be used, such as at least one of conductive carbon black (such as acetylene black, Ketjen black), carbon nanotubes, carbon fibers and graphite. In one embodiment of the present application, the mass percentage content of the positive electrode binder in the positive electrode material layer 201 is 0.01%-10%. Specifically, the mass percentage content of the positive electrode binder in the positive electrode material layer 201 can be, but not limited to, 0.015%-8%, 0.02%-7%, 0.02%-5% or 0.05%-4.5%, etc. In another embodiment of the present application, the conductive agent can be, but not limited to, at least one of acetylene black, carbon nanowires, graphite and graphene. In another embodiment of the present application, the mass percentage of the conductive agent in the positive electrode material layer 201 is 0.1%-20%. Specifically, the mass percentage of the conductive agent in the positive electrode material layer 201 can be, but is not limited to, 0.5%-18%, 1%-15%, 1%-10% or 3%-8.5%, etc.

[0063] In the embodiment of the present application, the negative electrode current collector 102 and the positive electrode current collector 202 are independently selected from metal foil or alloy foil. Among them, the metal foil includes copper, titanium, aluminum, platinum, iridium, ruthenium, nickel, tungsten, tantalum, gold or silver foil, and the alloy foil includes stainless steel, or an alloy containing at least one element of copper, titanium, aluminum, platinum, iridium, ruthenium, nickel, tungsten, tantalum, gold and silver. For example, the negative electrode current collector 102 can be specifically aluminum foil, and the positive electrode current collector 202 can be specifically copper foil. The thickness and surface roughness of the negative electrode current collector 102 and the positive electrode current collector 202 in the present application can be adjusted according to actual needs.

[0064] In an embodiment of the present application, the solid electrolyte layer 300 can be formed by coating and drying a slurry containing a solid electrolyte material and a solvent, and the components of the solid electrolyte layer 300 include a solid electrolyte material. In another embodiment of the present application, the solid electrolyte layer 300 may also contain a binder, and its material may be selected from the binder in the above-mentioned negative electrode material layer 101, which will not be repeated here. In one embodiment of the present application, the solid electrolyte layer 300 can be combined with the negative electrode material layer 101 by coating, and then the solid electrolyte layer 300 can be combined with the positive electrode 200 with the positive electrode material layer 201 by pressing.

[0065] In an embodiment of the present application, the solid electrolyte material for the positive electrode and the solid electrolyte material in the solid electrolyte layer 300 are independently selected from at least one of a garnet-type solid electrolyte and a sulfur-based solid electrolyte. The material of the solid electrolyte layer 300 is the same as or different from the solid electrolyte material for the positive electrode. For example, the composition of the solid electrolyte layer selects a reduction-resistant solid electrolyte material to protect the silicon-based composite negative electrode material 10 of the negative electrode, and further improves the cycle stability of the silicon-based composite negative electrode material 10. Furthermore, when preparing the solid electrolyte layer 300 and the positive electrode material layer 201, the particle size of the solid electrolyte material used can be 100nm-5μm. In one embodiment of the present application, the chemical formula of the garnet-type solid electrolyte is Li 7+p-q-3u Al u La 3-p X p Zr 2-q Y q O 12 , wherein 0<p≤1, 0<q≤1, 0<u≤1, X is selected from at least one of La, Ca, Sr, Ba and K, and Y is selected from at least one of Ta, Nb, W and Hf. In another embodiment of the present application, the sulfur-based solid electrolyte includes crystalline Li r Q s P t1 S z , glassy Li2S-P2S5 and glass-ceramic Li2S-P2S5 and their dopants, wherein the crystalline Li r Q s P t1 S z In which Q is selected from one or more of Si, Ge and Sn, r+4s+5t1=2z, 0≤s≤1.5. Glassy Li2S-P2S5 includes different products composed of Li2S and P2S5, such as Li7P3S 11 Or 70Li2S-30P2S5, etc.

[0066] In the embodiment of the present application, the ionic conductivity of the silicon-based composite negative electrode material 10 in the all-solid-state lithium battery at room temperature is 10-8 S cm -1 Above, the room temperature is 15℃-30℃.

[0067] In the embodiment of the present application, the electronic conductivity of the silicon-based composite negative electrode material 10 in the all-solid-state lithium battery at room temperature is 10 -2 S cm -1 Above, the room temperature is 15℃-30℃.

[0068] In an embodiment of the present application, a method for preparing an all-solid-state lithium battery is also provided, comprising:

[0069] S201: preparing the negative electrode 100: the silicon-based composite negative electrode material 10 is mixed with the first solvent, and at least one of a conductive agent and a binder is added to obtain a negative electrode mixed slurry; the negative electrode mixed slurry is coated on the negative electrode current collector 102, and after drying and pressing, the negative electrode 100 is obtained.

[0070] S202: preparing a solid electrolyte layer 300: in the presence of a protective gas, the solid electrolyte material and the second solvent are evenly mixed to obtain a solid electrolyte mixed slurry, the solid electrolyte mixed slurry is continuously coated on the negative electrode, and after drying, a solid electrolyte layer 300 is formed on the negative electrode 100.

[0071] S203: preparing positive electrode 200: mixing positive electrode active material, positive electrode solid electrolyte, conductive agent, positive electrode binder and third solvent evenly to obtain positive electrode mixed slurry; coating the positive electrode mixed slurry on positive electrode collector 202, drying and pressing to obtain positive electrode 200.

[0072] S204: In the presence of a protective gas, align the negative electrode 100 with the solid electrolyte layer 300 with the prepared positive electrode 200, fit the tabs, and obtain an all-solid-state lithium battery after hot pressing, vacuum sealing and isostatic pressing.

[0073] In the embodiment of the present application, the first solvent, the second solvent and the third solvent are independently selected from at least one of water, ethanol, toluene, xylene, anisole, acetonitrile, heptane, decane, ethyl acetate, ethyl propionate, butyl butyrate, N-methylpyrrolidone, acetone, etc. The amount of each solvent can generally be 50wt%-400wt% of the mass of dry materials in the corresponding mixed slurry.

[0074] In the embodiment of the present application, the tabletting may be, but is not limited to, roller pressed at 0-5 MPa.

[0075] In the embodiment of the present application, the temperature of the hot pressing treatment may be but is not limited to about 100°C, and the hot pressing treatment time may be but is not limited to 0.5h-3h; the isostatic pressing pressure may be but is not limited to above 100MPa, for example, the pressure is 100MPa-300MPa; the isostatic pressing treatment time may be but is not limited to 3min-10min.

[0076] The all-solid-state lithium battery provided in the present application, because it contains the above-mentioned silicon-based composite negative electrode material 10, has high battery capacity and good cycle performance, which is conducive to its application.

[0077] The present application is further described below with reference to a number of embodiments.

[0078] Example 1

[0079] A method for preparing an all-solid-state lithium battery comprises:

[0080] (1) Preparation of negative electrode

[0081] Under argon atmosphere, 1000 g of Li 1.71 Si-based material and 30 g of Li3OCl antiperovskite solid electrolyte material were placed in a ball mill and milled at 150 rpm for 20 min. The temperature was then raised to 300 °C at a rate of more than 10 °C / min and maintained for 30 min to obtain Li3OCl-coated Li 1.71 Si first coating; 1000g of the first coating and 100g of 70Li2S·30P2S5 glassy sulfur-based solid electrolyte material were placed in a ball mill and ball milled at 150rpm for 20min to obtain a silicon-based composite negative electrode material. The silicon-based composite negative electrode material is 70Li2S·30P2S5 coated with the first coating. The scanning electron microscopy (SEM) results of the sample cut by focused ion beam (FIB) show that Li in the silicon-based composite negative electrode material is 1.3% and 1.2% respectively. 1.71 The particle size of the Si silicon-based material core is about 200nm, the thickness of the Li3OCl antiperovskite solid electrolyte material layer is about 15nm, and the thickness of the 70Li2S·30P2S5 glassy sulfur-based solid electrolyte material layer is about 70nm.

[0082] 1000g of silicon-based composite negative electrode material, 10g of acetylene black, 10g of conductive carbon fiber, and 30g of binder SBR rubber were added to 1000mL of toluene, and then stirred in a blender to form a stable and uniform negative electrode slurry. The negative electrode slurry was uniformly and intermittently coated on a copper foil (width 160mm, thickness 16μm), then dried at 373K, and pressed by a roller press to obtain a negative electrode.

[0083] (2) Fabrication of solid electrolyte layer

[0084] Under an argon atmosphere, 600 g of 70Li2S·30P2S5 glassy solid electrolyte material was placed in 1200 g of toluene solution containing 30 g of butadiene rubber binder, and heated and stirred until a stable and uniform slurry was obtained; the slurry was continuously coated on the negative electrode obtained in step (1), and then dried at 373K to form a solid electrolyte layer with a thickness of 50 μm on the negative electrode.

[0085] (3) Preparation of positive electrode

[0086] 1000 g LiCoO2, 51 mL niobium ethoxide, 12 g lithium ethoxide, 1000 mL deionized water and 1000 mL ethanol were fully mixed. Under continuous stirring, ammonia water was added dropwise to adjust the pH to 10. The solution was evaporated to dryness and the obtained powder was heated at 400 °C for 8 h to obtain a LiCoO2 positive electrode active material coated with LiNbO3 on the surface.

[0087] Take 930g of the above-mentioned LiCoO2 positive electrode active material coated with LiNbO3, 150g of Li 10 GeP2S 12 Solid electrolyte material, 30g of binder butadiene rubber, 20g of acetylene black, and 20g of carbon fiber are added to 1500g of toluene solvent, and then stirred in a vacuum mixer to form a stable and uniform positive electrode mixed slurry; the positive electrode mixed slurry is uniformly and intermittently coated on an aluminum foil (width 160mm, thickness 16μm), and then dried at 393K. After being pressed by a roller press, a positive electrode material layer with a thickness of 100μm is formed on the aluminum foil to obtain a positive electrode.

[0088] (4) Fabrication of all-solid-state lithium batteries

[0089] Under a protective atmosphere, the positive electrode and the negative electrode with a solid electrolyte layer were aligned and placed in a tablet press, the tabs were fitted, hot pressed at 100°C for 1 hour, vacuum sealed with an aluminum-plastic film, and finally pressed at 200 MPa for 300 seconds in an isostatic press to obtain an all-solid-state lithium battery.

[0090] Example 2

[0091] A preparation of an all-solid-state lithium battery, which is substantially the same as Example 1, except that Li 1.71Si silicon-based material becomes Si material, 100g of 70Li2S·30P2S5 glassy sulfur-based solid electrolyte material becomes 150g, 10g of acetylene black becomes 30g, and 10g of conductive carbon fiber becomes 30g. Among them, the scanning electron microscope (SEM) results of the samples cut by focused ion beam (FIB) show that the particle size of the Si core in the silicon-based composite negative electrode material is about 100nm, the thickness of the Li3OCl antiperovskite solid electrolyte material layer is about 10nm, and the thickness of the 70Li2S·30P2S5 glassy sulfur-based solid electrolyte material layer is about 50nm.

[0092] Example 3

[0093] A preparation of an all-solid-state lithium battery, which is substantially the same as Example 1, except that Li 1.71 Si-based materials become silicon oxide materials (chemical formula is about SiO 0.8 ), 100g of 70Li2S·30P2S5 glassy sulfur-based solid electrolyte material becomes 150g, 10g of acetylene black becomes 30g, and 10g of conductive carbon fiber becomes 30g. Among them, the scanning electron microscope (SEM) results of the samples cut by focused ion beam (FIB) show that the particle size of the silicon oxide material core in the silicon-based composite negative electrode material is about 250nm, the thickness of the Li3OCl antiperovskite solid electrolyte material layer is about 15nm, and the thickness of the 70Li2S·30P2S5 glassy sulfur-based solid electrolyte material layer is about 100nm.

[0094] Example 4

[0095] Preparation of an all-solid-state lithium battery, which is substantially the same as Example 1, except that 30g of Li3OCl antiperovskite solid electrolyte material is changed to 250g, and 100g of 70Li2S·30P2S5 glassy sulfur-based solid electrolyte material is changed to 40g. Among them, the scanning electron microscopy (SEM) results of the sample cut by focused ion beam (FIB) show that the Li in the silicon-based composite negative electrode material is 1.71 The particle size of the Si silicon-based material core is about 200nm, the thickness of the Li3OCl antiperovskite solid electrolyte material layer is about 15nm, and the thickness of the 70Li2S·30P2S5 glassy sulfur-based solid electrolyte material layer is about 70nm.

[0096] Example 5

[0097] A preparation of an all-solid-state lithium battery is substantially the same as Example 1, except that 30 g of Li3OCl antiperovskite solid electrolyte material is replaced by 30 g of Li2OHCl antiperovskite solid electrolyte material. The scanning electron microscopy (SEM) results of the sample cut by focused ion beam (FIB) show that the Li1.71 The particle size of the Si silicon-based material core is about 200nm, the thickness of the Li3OCl antiperovskite solid electrolyte material layer is about 100nm, and the thickness of the 70Li2S·30P2S5 glassy sulfur-based solid electrolyte material layer is about 25nm.

[0098] In order to highlight the beneficial effects of the embodiments of the present application, the following comparative examples are provided:

[0099] Comparative Example 1

[0100] A preparation of an all-solid-state lithium battery, which is different from Example 1 in that a carbon-coated silicon negative electrode material is used to replace a silicon-based composite negative electrode material, wherein the preparation method of the carbon-coated silicon negative electrode material comprises: placing 1000g of Si and 240g of sucrose in 1000mL of deionized water and stirring evenly, then heating to 100°C during stirring, taking out the solid after the water evaporates, and heating to 300°C under an inert atmosphere to obtain a carbon-coated silicon negative electrode material. The carbon-coated silicon negative electrode material is directly used as the negative electrode, and the other steps remain unchanged.

[0101] Comparative Example 2

[0102] A preparation of an all-solid-state lithium battery, which differs from Example 1 in that the specific operation of step (1) is as follows: 1000 g of Si and 240 g of sucrose are placed in 1000 mL of deionized water and stirred evenly, then heated to 100° C. during stirring, and after the water evaporates, the solid is taken out and heated to 300° C. under an inert atmosphere to obtain a carbon-coated silicon negative electrode material; 1000 g of the carbon-coated silicon negative electrode material is mixed with 150 g of 70Li2S·30P2S5 glassy electrolyte material, 100 g of acetylene black, 30 g of binder SBR, and 1000 mL of toluene to prepare a mixed slurry, which is coated on a copper foil, dried, and pressed into a sheet to obtain a negative electrode.

[0103] Comparative Example 3

[0104] A method for preparing an all-solid-state lithium battery, which is different from Example 1 in that the Li3OCl in step (1) is coated with Li 1.71 The first coating of Si replaces the silicon-based composite negative electrode material, and is added to 1000 mL of toluene with 10 g of acetylene black, 10 g of conductive carbon fiber, and 30 g of binder SBR rubber, and then stirred in a blender to form a stable and uniform negative electrode slurry. The scanning electron microscopy (SEM) results of the sample cut by focused ion beam (FIB) show that the Li 1.71 The particle size of the Si silicon-based material core is about 200nm, and the thickness of the Li3OCl antiperovskite solid electrolyte material layer is about 15nm.

[0105] Comparative Example 4

[0106] A preparation method of an all-solid-state lithium battery, which is different from Example 1 in that 1000g of Li 1.71 The Si-based material and 100g of 70Li2S·30P2S5 glassy sulfur-based solid electrolyte material were placed in a ball mill and milled at 150rpm for 20min to obtain a Si-based composite negative electrode material. The subsequent operation steps remained unchanged. The scanning electron microscopy (SEM) results of the sample cut by focused ion beam (FIB) showed that the Li in the Si-based composite negative electrode material 1.71 The particle size of the Si silicon-based material core is about 200nm, and the thickness of the 70Li2S·30P2S5 glassy sulfur-based solid electrolyte material layer is about 70nm.

[0107] Comparative Example 5

[0108] A preparation method of an all-solid-state lithium battery is substantially the same as that of Example 1, except that the coating order of the Li3OCl antiperovskite solid electrolyte material and the 70Li2S·30P2S5 glassy sulfur-based solid electrolyte material is opposite. The preparation method comprises the following steps: in an argon atmosphere, 1000 g of Li 1.71 The Si-based material and 103 g of 70Li2S·30P2S5 glassy sulfur-based solid electrolyte material were placed in a ball mill and milled at 150 rpm for 20 min to obtain Li2S·30P2S5 glassy sulfur-based solid electrolyte material coated with Li 1.71 Si, then 1000g of the material and 29g of Li3OCl antiperovskite solid electrolyte material were placed in a ball mill, and ball milled at 100rpm for 10min, and then heated to 300℃ at a rate of more than 10℃ / min and maintained for 30min to obtain a silicon-based composite negative electrode material. The scanning electron microscopy (SEM) results of the sample cut by focused ion beam (FIB) showed that Li 1.71 The particle size of the Si silicon-based material core is about 200nm, the thickness of the 70Li2S·30P2S5 glassy sulfur-based solid electrolyte material layer is about 70nm, and the thickness of the Li3OCl antiperovskite solid electrolyte material layer is about 15nm.

[0109] Performance Testing

[0110] The all-solid-state lithium batteries obtained in the above embodiments and comparative examples were tested for battery cycle life, and the testing method was as follows: 20 all-solid-state lithium battery samples prepared in each embodiment and comparative example were taken, and each battery was subjected to a charge and discharge cycle test at a rate of 0.1C at 298±1K on a LAND CT 2001C secondary battery performance testing device.

[0111] The test steps are as follows: leave for 10 minutes; charge at constant voltage to 4.25V / 0.05C and then stop; leave for 10 minutes; discharge at constant current to 3V, which is one cycle, and record the first cycle discharge capacity. Repeat the above cycle steps, when the battery capacity is lower than 80% of the first discharge capacity during the cycle, the cycle is terminated, and the number of cycles at the end of the cycle is the cycle life of the battery. The average value of each group is taken, and the results are shown in Table 1.

[0112] Table 1 Cycle life test data of each group of samples

[0113]

[0114] It can be seen from Table 1 that the discharge capacity and cycle life of Comparative Examples 1 and 3 are very poor, and the discharge capacity and cycle life of Comparative Examples 2 and 4 are significantly lower than those of the embodiments; the battery performance of Comparative Example 1 using the carbon-coated silicon negative electrode material commonly used in lithium batteries with electrolyte is extremely poor, indicating that the negative electrode material is not suitable for all-solid-state lithium batteries; but the battery performance of the obtained battery is improved compared with Comparative Example 1 by mixing the carbon-coated silicon negative electrode material with the solid electrolyte (Comparative Example 2), but it is still far inferior to that of the battery made of the silicon negative electrode material of the embodiment of the present application. All-solid-state lithium batteries made of silicon-based composite negative electrode materials; all-solid-state lithium batteries made of silicon-based composite negative electrode materials using a single-layer coating method (Comparative Examples 3 and 4), and all-solid-state lithium batteries made of silicon-based composite negative electrode materials obtained by the reverse coating order (Comparative Example 5) are far inferior to the all-solid-state lithium batteries made of the silicon-based composite negative electrode materials of the embodiments of the present application; the all-solid-state lithium battery made of the silicon-based composite negative electrode material of the present application has a higher negative electrode discharge specific capacity and a better battery cycle life, which is conducive to its widespread use.

[0115] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A silicon-based composite negative electrode material, characterized in that: The silicon-based composite negative electrode material comprises a silicon-based material core, and an antiperovskite solid electrolyte layer and a sulfur-based solid electrolyte layer which sequentially cover the silicon-based material core, wherein the antiperovskite solid electrolyte layer comprises Li 3-t OH t A, wherein A is at least one of Cl, Br and I, 0≤t≤2, the thickness of the antiperovskite solid electrolyte layer is 5nm-200nm, and the thickness of the sulfur-based solid electrolyte layer is 20nm-3μm.

2. The silicon-based composite negative electrode material according to claim 1, characterized in that: The thickness of the sulfide solid electrolyte layer is greater than the thickness of the antiperovskite solid electrolyte layer.

3. The silicon-based composite negative electrode material according to claim 2, characterized in that: The thickness ratio of the antiperovskite solid electrolyte layer to the sulfur-based solid electrolyte layer is 1:(2-100).

4. The silicon-based composite negative electrode material according to claim 1, characterized in that: The particle size of the silicon-based material core is 10nm-1μm.

5. The silicon-based composite negative electrode material according to claim 1, characterized in that: The silicon-based material core includes at least one of a single silicon material, a silicon alloy material, a silicon-oxygen material and a silicon-carbon material; the silicon alloy material includes a lithium-silicon alloy Li x Si, 0<x≤4.4; the silicon-oxygen material includes silicon oxide SiO y , 0<y<2.

6. The silicon-based composite negative electrode material according to claim 1, characterized in that: The sulfur-based solid electrolyte layer includes glassy mLi2S·nP2S5 and crystalline Li a P b S c At least one of the following, wherein m+n=100, m>n, a, b and c are positive integers greater than zero, a+5b=2c, 1≤a / b<4.

7. A method for preparing a silicon-based composite negative electrode material, characterized in that: include: The silicon-based material is coated with an antiperovskite solid electrolyte material to obtain a first coating, wherein the antiperovskite solid electrolyte material includes Li 3-t OH t A, wherein A is at least one of Cl, Br and I, 0≤t≤2; The first coating is coated with a sulfur-based solid electrolyte to obtain a silicon-based composite negative electrode material, wherein the silicon-based composite negative electrode material includes a silicon-based material core, and an antiperovskite solid electrolyte layer and a sulfur-based solid electrolyte layer that sequentially coat the silicon-based material core, wherein the thickness of the antiperovskite solid electrolyte layer is 5nm-200nm, and the thickness of the sulfur-based solid electrolyte layer is 20nm-3μm.

8. The preparation method according to claim 7, characterized in that: The preparation method further comprises: The silicon-based material and the antiperovskite solid electrolyte material are mixed and ball-milled to obtain the first coating; The first coating material is mixed with the sulfur-based solid electrolyte material and ball-milled to obtain the silicon-based composite negative electrode material.

9. An all-solid-state lithium battery, characterized in that: It comprises a positive electrode, a negative electrode and a solid electrolyte layer located between the positive electrode and the negative electrode, wherein the negative electrode comprises the silicon-based composite negative electrode material as described in any one of claims 1 to 6 or the silicon-based composite negative electrode material prepared by the preparation method as described in any one of claims 7 to 8.

10. The all-solid-state lithium battery according to claim 9, characterized in that: The negative electrode includes a negative electrode current collector and a negative electrode material layer disposed on the negative electrode current collector. The negative electrode material layer includes the silicon-based composite negative electrode material, and the negative electrode material layer does not contain a solid electrolyte material.

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