A negative electrode active material and its preparation method, negative electrode sheet, and all-solid-state battery

Abstract

This invention provides a negative electrode active material and its preparation method, a negative electrode sheet, and an all-solid-state battery. The negative electrode active material includes a first element and a second element, which interact with each other. The first and second elements in the negative electrode active material satisfy the following condition: 2.0 ≤ S*M / C ≤ 4.0, where M is defined as the ratio of the mass of the first element to the mass of the second element, S is defined as the ratio of the expansion rate of the first element after complete lithium intercalation to that of the second element after complete lithium intercalation, and C is defined as the ratio of the 0.1C specific capacity of the first element after complete lithium intercalation to that of the second element after complete lithium intercalation. This invention's negative electrode active material, its preparation method, the negative electrode sheet, and the all-solid-state battery can simultaneously improve the negative electrode expansion rate and electron / ion conduction, thereby improving the solid-solid interface and achieving high energy density and long cycle life in all-solid-state batteries.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more specifically, to a negative electrode active material and its preparation method, a negative electrode sheet, and an all-solid-state battery. Background Technology

[0002] Currently, liquid lithium-ion batteries face challenges such as difficulty in achieving breakthroughs in energy density and improving safety, leading to the development of all-solid-state batteries. All-solid-state batteries replace traditional electrolytes with safer and thinner solid electrolytes, improving their thermal runaway temperature and energy density.

[0003] To develop high-energy-density all-solid-state batteries, silicon-based materials or lithium metal are generally used as the anode. These anode materials expand significantly during charge and discharge, easily causing active lithium loss and SEI formation. This is accompanied by the collapse of the electron and ion conduction networks in the anode, ultimately leading to battery performance failure. Silicon anodes, in particular, exhibit large expansion and poor cycle performance. Furthermore, the expansion of silicon anodes can cause structural collapse and solid-solid interface separation, preventing them from contributing capacity in subsequent charge and discharge processes.

[0004] Therefore, it is necessary to develop anode materials that are suitable for high energy density and low expansion all-solid-state batteries.

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

[0006] The purpose of this invention is to address the shortcomings of existing technologies by providing a negative electrode active material and its preparation method, a negative electrode sheet, and an all-solid-state battery, which can simultaneously improve the negative electrode expansion rate and electron and ion conduction, thereby improving the solid-solid interface and achieving high energy density and long cycle life in all-solid-state batteries.

[0007] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted: A negative electrode active material, comprising a first element and a second element, wherein the first element and the second element form an interaction force; The first and second elements in the negative electrode active material satisfy the following condition: 2.0 ≤ S*M / C ≤ 4.0. Wherein, parameter M is defined as the ratio of the mass of the first element to the mass of the second element, parameter S is defined as the ratio of the expansion rate of the first element after complete lithium intercalation to the expansion rate of the second element after complete lithium intercalation, and parameter C is defined as the ratio of the 0.1C gram capacity of the first element after complete lithium intercalation to the 0.1C gram capacity of the second element after complete lithium intercalation.

[0008] Furthermore, the parameter S satisfies: 1.2≤S≤20.0.

[0009] Furthermore, the parameter M satisfies: 1.0≤M≤10.0.

[0010] Furthermore, the parameter C satisfies: 1.5≤C≤15.0.

[0011] Furthermore, the first element can be a single element or a combination of multiple elements.

[0012] Furthermore, the first element is silicon.

[0013] Furthermore, the second element is a single element or a combination of multiple elements; the second element includes at least one of Sn, Ge, Al, Ga, In, Sb, Pb, Bi, Zn, P, and C.

[0014] Furthermore, the first element and the second element are bonded together by a bonding action to form an interaction force, wherein the bonding action includes at least one of metallic bond, covalent bond, ionic bond, and van der Waals force.

[0015] The preparation method of the above-mentioned negative electrode active material includes: mixing the first element powder and the second element powder in a ratio of parameter M, and then ball milling to obtain the negative electrode active material.

[0016] Furthermore, the balls were milled under a protective atmosphere.

[0017] Furthermore, the protective atmosphere includes at least one of argon, nitrogen, and helium.

[0018] Furthermore, the ball milling process is controlled at a temperature of 100~200℃ and a speed of 200~400rpm for 5~20h.

[0019] Furthermore, the negative electrode active material is ball-milled until the particle size Dv50 is 1~20μm.

[0020] A negative electrode sheet comprising the above-mentioned negative electrode active material or the negative electrode active material prepared by the above-mentioned preparation method.

[0021] An all-solid-state battery comprising the above-mentioned negative electrode active material, the negative electrode active material prepared by the above-mentioned preparation method, or the above-mentioned negative electrode sheet.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The negative electrode active material of this invention is a binary or multi-element negative electrode material, which is composed of a first element and a second element with different expansion rates, capable of lithiation during charge and discharge processes and contributing to capacity. The first element and the second element are bonded together through interaction. During charging, the first element and the second element expand due to lithium intercalation. Due to the different expansion rates, they form a connected pore structure in the bulk phase. At the same time, due to the interaction force between the first element and the second element, the lower expansion element can restrain the expansion rate of the higher expansion element. The pores formed are a continuous structure, which can avoid the interruption of electron and ion conduction pathways in the structure caused by single-phase expansion. Ultimately, it can simultaneously improve the negative electrode expansion rate and electron and ion conduction, thereby improving the solid-solid interface and achieving high energy density and long cycle life in all-solid-state batteries.

[0023] 2. The first element in the negative electrode active material of the present invention is preferably silicon, providing a binary or multi-element silicon negative electrode. The second element in the silicon negative electrode has a different expansion rate than silicon lithium intercalation, which can form pores in situ during lithium intercalation, improve the expansion during the lithium intercalation process of the silicon negative electrode, and improve the expansion problem during the cycle process, thereby improving the cycle performance.

[0024] 3. The present invention provides a binary or multi-element silicon anode in which silicon interacts with the second element. This interaction can, on the one hand, alleviate structural collapse, suppress interface separation, and improve the solid-solid interface; on the other hand, it can further suppress expansion, reduce anode expansion, and thus improve cycle performance. Attached Figure Description

[0025] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0026] Figure 1 The image shows the XRD pattern of the negative electrode active material prepared in Example 1 of this invention. Detailed Implementation

[0027] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. However, those skilled in the art will understand that the embodiments described below are some embodiments of the present invention, but not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0028] A negative electrode active material includes a first element and a second element, wherein the first element and the second element form an interaction force; wherein the first element and the second element in the negative electrode active material satisfy: 2.0≤S*M / C≤4.0 (the parameter S*M / C is a point value among 2.0, 2.5, 3.0, 3.5, and 4, or a numerical range between the point values), wherein the parameter M is defined as the ratio of the mass m1 of the first element to the mass m2 of the second element, the parameter S is defined as the ratio of the expansion rate s1 of the first element after complete lithium intercalation to the expansion rate s2 of the second element after complete lithium intercalation, and the parameter C is defined as the ratio of the 0.1C specific capacity c1 of the first element after complete lithium intercalation to the 0.1C specific capacity c2 of the second element after complete lithium intercalation.

[0029] In this invention, parameter M is an independent parameter, while parameters S and C are related to the intrinsic properties of the element and the element synthesis conditions (such as ball milling parameters).

[0030] The test method for the expansion rate s1 and the specific capacity c1 of the first element after complete lithium intercalation is as follows: the first element is ball-milled separately to obtain a single-component negative electrode active material. The expansion rate s1 and the 0.1C specific capacity c1 of the first element after complete lithium intercalation can be measured by assembling a half cell with the single negative electrode active material.

[0031] The test methods for the expansion rate s2 and the specific capacity c2 of the second element after complete lithium intercalation are as follows: the second element is ball-milled separately to obtain a single-component negative electrode active material. The expansion rate s2 and the 0.1C specific capacity c2 of the second element after complete lithium intercalation can be measured by assembling a half cell with the single negative electrode active material.

[0032] In this invention, parameters S, C, and M are in a physicochemically linked state. That is, when parameter S changes, C / M will also change accordingly. This invention summarizes the relevant linkage law, namely the optimal value of S*M / C, which can simultaneously improve the negative electrode expansion rate and electron and ion conduction, thereby improving the solid-solid interface and achieving high energy density and long cycle life in all-solid-state batteries.

[0033] In some implementations, the parameter S satisfies: 1.2≤S≤20.0, where the parameter S is a point value among 1.2, 1.5, 2.0, 5.0, 10.0, 15.0, and 20.0, or a numerical range between point values.

[0034] In some implementations, the parameter M satisfies: 1.0≤M≤10.0, and the parameter M is a point value among 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, and 10.0 or satisfies a numerical range between point values.

[0035] In some implementations, the parameter C satisfies: 1.5≤C≤15.0, where parameter C is a point value among 1.5, 2.0, 5.0, 10.0, and 15.0, or a numerical range between point values.

[0036] Optionally, the first element is a single element or a combination of multiple elements, and preferably the first element is silicon.

[0037] Optionally, the second element can be a single element or a combination of multiple elements.

[0038] Optionally, the second element includes at least one of an element that can undergo an electrochemical reaction with lithium to form an alloy or an element that can undergo a lithium intercalation (intercalation) reaction with lithium to form an intercalation compound.

[0039] Optionally, the second element includes at least one of Sn, Ge, Al, Ga, In, Sb, Pb, Bi, Zn, P, and C.

[0040] Optionally, the second element is one of Sn, Ge, Al, Ga, In, Sb, Pb, Bi, Zn, P, C, etc.

[0041] In some implementations, the first element and the second element are bonded together to form an interaction force, thereby improving expansion and ion and electron pathways.

[0042] Optionally, the bonding effect includes at least one of metallic bonds, covalent bonds, ionic bonds, and van der Waals forces.

[0043] A method for preparing a negative electrode active material includes: mixing a first element powder and a second element powder in a ratio of parameter M, and ball milling the mixture to obtain the negative electrode active material.

[0044] In some implementations, ball milling is performed under a protective atmosphere.

[0045] Optionally, the protective atmosphere includes at least one of argon, nitrogen, and helium.

[0046] In some embodiments, the ball milling process is controlled at a temperature of 100~200℃ (including but not limited to 100℃, 110℃, 120℃, 130℃, 140℃, 150℃, 160℃, 170℃, 180℃, 190℃, 200℃) and ball milled at a speed of 200~400rpm (including but not limited to 200rpm, 250rpm, 300rpm, 350rpm, 400rpm) for 5~20h (including but not limited to 5h, 10h, 15h, 20h).

[0047] In some embodiments, the negative electrode active material is ball-milled to a particle size Dv50 of 1~20μm (including but not limited to 1μm, 5μm, 10μm, 15μm, 20μm).

[0048] A negative electrode sheet comprising the above-mentioned negative electrode active material or the negative electrode active material prepared by the above-mentioned preparation method.

[0049] An all-solid-state battery comprising the above-mentioned negative electrode active material, the negative electrode active material prepared by the above-mentioned preparation method, or the above-mentioned negative electrode sheet.

[0050] Example 1 A method for preparing a negative electrode active material includes the following steps: 1. Weigh out Si powder and Al powder according to the ratio of parameter M in Table 1 and mix them. 2. After mixing, place the mixture in a ball mill jar. The gas in the ball mill jar is argon. Perform ball milling according to the ball milling process parameters in Table 1 to prepare the negative electrode active material. 3. Transfer the prepared negative electrode active material to an inert gas environment for storage.

[0051] The XRD pattern of the negative electrode active material prepared in Example 1 is shown in [reference needed]. Figure 1 This can indirectly prove the existence of bonding.

[0052] Example 2 A method for preparing a negative electrode active material includes the following steps: 1. Weigh out Si powder and Sn powder according to the ratio of parameter M in Table 1 and mix them. 2. After mixing, place the mixture in a ball mill jar. The gas in the ball mill jar is argon. Perform ball milling according to the ball milling process parameters in Table 1 to prepare the negative electrode active material. 3. Transfer the prepared negative electrode active material to an inert gas environment for storage.

[0053] Example 3 A method for preparing a negative electrode active material includes the following steps: 1. Weigh out Si powder and Bi powder according to the ratio of parameter M in Table 1 and mix them. 2. After mixing, place the mixture in a ball mill jar. The gas in the ball mill jar is argon. Perform ball milling according to the ball milling process parameters in Table 1 to prepare the negative electrode active material. 3. Transfer the prepared negative electrode active material to an inert gas environment for storage.

[0054] Example 4 A method for preparing a negative electrode active material includes the following steps: 1. Weigh out Si powder and C powder according to the ratio of parameter M in Table 1 and mix them. 2. After mixing, place the mixture in a ball mill jar. The gas in the ball mill jar is argon. Perform ball milling according to the ball milling process parameters in Table 1 to prepare the negative electrode active material. 3. Transfer the prepared negative electrode active material to an inert gas environment for storage.

[0055] Example 5 A method for preparing a negative electrode active material includes the following steps: 1. Weigh out Si powder and Al powder according to the ratio of parameter M in Table 1 and mix them. 2. After mixing, place the mixture in a ball mill jar. The gas in the ball mill jar is argon. Perform ball milling according to the ball milling process parameters in Table 1 to prepare the negative electrode active material. 3. Transfer the prepared negative electrode active material to an inert gas environment for storage.

[0056] Example 6 A method for preparing a negative electrode active material includes the following steps: 1. Weigh out Si powder and Al powder according to the ratio of parameter M in Table 1 and mix them. 2. After mixing, place the mixture in a ball mill jar. The gas in the ball mill jar is argon. Perform ball milling according to the ball milling process parameters in Table 1 to prepare the negative electrode active material. 3. Transfer the prepared negative electrode active material to an inert gas environment for storage.

[0057] Comparative Example 1 A method for preparing a negative electrode active material includes the following steps: 1. Weigh Si powder and Al powder according to the ratio of parameter M in Table 1 and mix them to prepare negative electrode active material; 2. Transfer the prepared negative electrode active material to an inert gas environment for storage.

[0058] Comparative Example 2 A method for preparing a single-component negative electrode active material includes the following steps: 1. The Si powder was ball-milled separately according to the ball milling process parameters in Table 1 to obtain a single-component negative electrode active material. 2. The prepared single-component negative electrode active material is transferred to an inert gas environment for storage.

[0059] Comparative Example 3 A method for preparing a single-component negative electrode active material includes the following steps: 1. Al powder was ball-milled separately according to the ball milling process parameters in Table 1 to obtain a single-component negative electrode active material; 2. The prepared single-component negative electrode active material is transferred to an inert gas environment for storage.

[0060] Comparative Example 4 A method for preparing a negative electrode active material includes the following steps: 1. Weigh out Si powder and Al powder according to the ratio of parameter M in Table 1 and mix them. 2. After mixing, place the mixture in a ball mill jar. The gas in the ball mill jar is argon. Perform ball milling according to the ball milling process parameters in Table 1 to prepare the negative electrode active material. 3. Transfer the prepared negative electrode active material to an inert gas environment for storage.

[0061] Comparative Example 5 A method for preparing a negative electrode active material includes the following steps: 1. Weigh out Si powder and Al powder according to the ratio of parameter M in Table 1 and mix them. 2. After mixing, place the mixture in a ball mill jar. The gas in the ball mill jar is argon. Perform ball milling according to the ball milling process parameters in Table 1 to prepare the negative electrode active material. 3. Transfer the prepared negative electrode active material to an inert gas environment for storage.

[0062] Comparative Example 6 A method for preparing a negative electrode active material includes the following steps: 1. Weigh out Si powder and Ge powder according to the ratio of parameter M in Table 1 and mix them. 2. After mixing, place the mixture in a ball mill jar. The gas in the ball mill jar is argon. Perform ball milling according to the ball milling process parameters in Table 1 to prepare the negative electrode active material. 3. Transfer the prepared negative electrode active material to an inert gas environment for storage.

[0063] Comparative Example 7 A method for preparing a negative electrode active material includes the following steps: 1. Weigh out Si powder and C powder according to the ratio of parameter M in Table 1 and mix them. 2. After mixing, place the mixture in a ball mill jar. The gas in the ball mill jar is argon. Perform ball milling according to the ball milling process parameters in Table 1 to prepare the negative electrode active material. 3. Transfer the prepared negative electrode active material to an inert gas environment for storage.

[0064] Comparative Example 8 A method for preparing a negative electrode active material includes the following steps: 1. Weigh out Si powder and P powder according to the ratio of parameter M in Table 1 and mix them. 2. After mixing, place the mixture in a ball mill jar. The gas in the ball mill jar is argon. Perform ball milling according to the ball milling process parameters in Table 1 to prepare the negative electrode active material. 3. Transfer the prepared negative electrode active material to an inert gas environment for storage.

[0065] Comparative Example 9 A method for preparing a negative electrode active material includes the following steps: 1. Weigh out Si powder and Bi powder according to the ratio of parameter M in Table 1 and mix them. 2. After mixing, place the mixture in a ball mill jar. The gas in the ball mill jar is argon. Perform ball milling according to the ball milling process parameters in Table 1 to prepare the negative electrode active material. 3. Transfer the prepared negative electrode active material to an inert gas environment for storage.

[0066] Comparative Example 10 A method for preparing a negative electrode active material includes the following steps: 1. Weigh out Si powder and Al powder according to the ratio of parameter M in Table 1 and mix them. 2. After mixing, place the mixture in a ball mill jar. The gas in the ball mill jar is argon. Perform ball milling according to the ball milling process parameters in Table 1 to prepare the negative electrode active material. 3. Transfer the prepared negative electrode active material to an inert gas environment for storage.

[0067] Comparative Example 11 A method for preparing a negative electrode active material includes the following steps: 1. Weigh out Si powder and Sn powder according to the ratio of parameter M in Table 1 and mix them. 2. After mixing, place the mixture in a ball mill jar. The gas in the ball mill jar is argon. Perform ball milling according to the ball milling process parameters in Table 1 to prepare the negative electrode active material. 3. Transfer the prepared negative electrode active material to an inert gas environment for storage.

[0068] The physicochemical properties of the preparation methods in Examples 1-6 and Comparative Examples 1-11 are shown in Table 1.

[0069] Table 1 Physicochemical properties of the preparation methods in Examples 1-6 and Comparative Examples 1-11

[0070] Experimental example: I. The preparation of all-solid-state batteries using the negative electrode active materials prepared in Examples 1-6 and Comparative Examples 1-11 includes the following steps: 1. The prepared negative electrode active material, electrolyte (Li6PS5Cl), conductive agent (VGCF), binder (PAA), and solvent (NMP) are mixed in a ratio of 70:25:5:1:100 to form a slurry and coated onto copper foil. The solvent is dried at 60°C to obtain the negative electrode sheet.

[0071] 2. The positive electrode active material (LiNi) 0.8 Co 0.1 Mn 0.1 O2): electrolyte (Li6PS5Cl): conductive agent (VGCF): binder (PVDF): solvent (NMP) are mixed in a ratio of 80:15:5:1:100 to form a slurry, which is then coated onto aluminum foil. The solvent is dried at 60°C to obtain the positive electrode sheet.

[0072] 3. The positive electrode, 100mg Li6PS5Cl powder, and negative electrode are placed in the mold battery in sequence to assemble a full cell, and then pressed at 50MPa to obtain a solid-state battery.

[0073] II. The all-solid-state battery tests are as follows (test results are shown in Table 2): 1. 0.1C capacity: The first charge is 0.1C to 4.2V, rested for 10 minutes, and then discharged at 0.1C to 2.5V. The discharge capacity is divided by the mass of the positive electrode active material to obtain the 0.1C capacity.

[0074] 2. Expansion rate: The initial mold battery pressure is recorded by a pressure sensor. After the first full charge at 0.1C, the full charge pressure is recorded. The expansion rate is calculated as full charge pressure / initial pressure - 1.

[0075] 3. 0.5C Cycle Retention Rate: Charge to 4.2V at 0.5C, let stand for 10 minutes, then discharge to 2.5V at 0.5C. This constitutes one cycle. After 100 cycles, record the ratio of the discharge capacity of the 100th cycle to the discharge capacity of the 1st cycle as the 0.5C cycle retention rate.

[0076] Table 2. Test data for all-solid-state batteries prepared from negative electrode active materials in Examples 1-6 and Comparative Examples 1-11.

[0077] The parameters S, C, M, and S*M / C of the negative electrode active materials prepared in Examples 1-4 all fall within the numerical range of this invention, exhibiting the optimal 0.1C specific capacity, the lowest expansion rate, and the optimal 0.5C cycle retention rate.

[0078] The parameters S*M / C of the negative electrode active materials prepared in Examples 5-6 are within the range of values ​​in this invention. The specific capacity at 0.1C, the expansion rate, and the cycle retention rate at 0.5C are slightly worse than those in Examples 1-4.

[0079] The negative electrode active material prepared in Comparative Examples 4-5 has a parameter S*M / C that is outside the numerical range of this invention, and its 0.1C specific capacity, expansion rate and 0.5C cycle retention rate are poor.

[0080] The parameters S of the negative electrode active materials prepared in Comparative Examples 6-7 are outside the numerical range of this invention, with slightly poorer 0.1C specific capacity, expansion rate and 0.5C cycle retention rate.

[0081] The parameter C of the negative electrode active material prepared in Comparative Examples 8-9 is outside the range boundary, and the specific capacity at 0.1C, expansion rate and cycle retention rate at 0.5C are slightly worse.

[0082] The parameters M of the negative electrode active materials prepared in Comparative Examples 10-11 are outside the range boundary, and the specific capacity at 0.1C, expansion rate and cycle retention rate at 0.5C are slightly worse.

[0083] In the negative electrode active material prepared in Comparative Example 1, Si and Al elements were mixed by simple mechanical means that Si and Al elements could not form an interaction force, which could not improve the expansion and ion and electron pathways. The 0.1C specific capacity, expansion rate and 0.5C cycle retention rate were poor.

[0084] The single-component negative electrode active material prepared in Comparative Example 2, without the addition of a second element, could not improve the expansion and ion and electron pathways, and had the worst specific capacity at 0.1C, expansion rate, and cycle retention rate at 0.5C.

[0085] The single-component negative electrode active material prepared in Comparative Example 3, without the addition of the first element, could not form continuous pores during the lithium insertion / extraction process, and could not improve expansion and ion / electron pathways. It had the worst specific capacity at 0.1C, expansion rate, and cycle retention rate at 0.5C.

[0086] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A negative electrode active material, characterized in that, The negative electrode active material includes a first element and a second element, and the first element and the second element form an interaction force. The first and second elements in the negative electrode active material satisfy the following condition: 2.0 ≤ S*M / C ≤ 4.

0. Wherein, parameter M is defined as the ratio of the mass of the first element to the mass of the second element, parameter S is defined as the ratio of the expansion rate of the first element after complete lithium intercalation to the expansion rate of the second element after complete lithium intercalation, and parameter C is defined as the ratio of the 0.1C capacity of the first element after complete lithium intercalation to the 0.1C capacity of the second element after complete lithium intercalation. The first element is silicon; The second element is a single element or a combination of multiple elements; the second element includes at least one of Sn, Ge, Al, Ga, In, Sb, Pb, Bi, Zn, P, and C. The parameter S satisfies: 1.2 ≤ S ≤ 20.0; The parameter M satisfies: 1.0 ≤ M ≤ 10.0; The parameter C satisfies: 1.5 ≤ C ≤ 15.0; The method for preparing the negative electrode active material includes: mixing the first element powder and the second element powder in a ratio of parameter M, and then ball milling to obtain the negative electrode active material. The ball milling process is controlled at a temperature of 100~200℃ and a speed of 200~400rpm for 5~20h.

2. The negative electrode active material according to claim 1, characterized in that, The first element and the second element are bonded together by a bonding action to form an interaction force, wherein the bonding action includes at least one of metallic bond, covalent bond, ionic bond, and van der Waals force.

3. The negative electrode active material according to claim 1, characterized in that, It should include at least one of the following technical features: (1) Ball milling under a protective atmosphere; (2) The protective atmosphere includes at least one of argon, nitrogen, and helium; (3) The negative electrode active material is ball-milled until the particle size Dv50 is 1~20μm.

4. A negative electrode sheet, characterized in that, It includes the negative electrode active material as described in any one of claims 1 to 3.

5. An all-solid-state battery, characterized in that, It comprises the negative electrode active material as described in any one of claims 1 to 3 or the negative electrode sheet as described in claim 4.

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