Silicon-based negative electrode solid-state battery and method of manufacturing the same

Abstract

The application relates to the technical field of batteries, and provides a silicon-based negative electrode solid-state battery and a preparation method thereof. The preparation method comprises the following steps: assembling a positive electrode, a solid electrolyte layer and a silicon-based negative electrode to obtain a prefabricated solid-state battery; performing a charge-discharge cycle on the prefabricated solid-state battery under the condition of applying a first pressure; after the prefabricated solid-state battery is charged for the first time, performing a pressing treatment on the prefabricated solid-state battery under the condition of applying a second pressure, wherein the second pressure is greater than the first pressure; continuing to perform the charge-discharge cycle on the prefabricated solid-state battery after the pressing treatment under the condition of applying the first pressure, and a silicon-based negative electrode solid-state battery is prepared. The prefabricated solid-state battery after the first charging is subjected to the pressing treatment, the interface contact condition of the silicon-based negative electrode is effectively improved, the structural stability of the silicon-based negative electrode is improved, and therefore the electrochemical performance of the silicon-based negative electrode solid-state battery is effectively improved.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of batteries, in particular to a silicon-based negative electrode solid-state battery and a preparation method thereof. BACKGROUND

[0002] The silicon-based negative electrode has the advantages of high specific capacity, low cost, small risk of lithium precipitation and good interface compatibility, and has become an important research object of sulfide solid-state batteries. However, in the process of lithium extraction and insertion, the volume change of the silicon material is large, which reduces the stability of the electrode structure, hinders the transmission of ions and electrons, increases the polarization and causes capacity loss, and seriously affects the rate and cycle performance of the solid-state silicon-based negative electrode. Therefore, how to maintain good contact between electrode components during the lithium extraction and insertion process is very important for improving the electrochemical performance of the solid-state silicon-based negative electrode. SUMMARY

[0003] Based on this, an embodiment of the application provides a silicon-based negative electrode solid-state battery with good interface contact and a preparation method thereof.

[0004] In a first aspect, the application provides a preparation method of a silicon-based negative electrode solid-state battery, and the preparation method comprises:

[0005] Assembling a positive electrode, a solid electrolyte layer and a silicon-based negative electrode to obtain a pre-prepared solid-state battery;

[0006] Performing charge and discharge cycles on the pre-prepared solid-state battery under a state of applying a first pressure, after the pre-prepared solid-state battery is charged for the first time, performing pressing treatment on the pre-prepared solid-state battery under a state of applying a second pressure, and the second pressure is greater than the first pressure;

[0007] Continuing to perform charge and discharge cycles on the pre-prepared solid-state battery after the pressing treatment under the state of applying the first pressure to obtain the silicon-based negative electrode solid-state battery.

[0008] In some embodiments, the rate of the first charge of the pre-prepared solid-state battery is 0.05C-0.2C.

[0009] In some embodiments, the state of charge of the pre-prepared solid-state battery after the first charge is 30%-100%.

[0010] In some embodiments, the first pressure is 1MPa-200MPa.

[0011] In some embodiments, the second pressure is 200MPa-1500MPa.

[0012] In some embodiments, the pressing treatment time is 1min-10min.

[0013] In some embodiments, the method for assembling the pre-prepared solid-state battery comprises:

[0014] pressing the first solid-state electrolyte material to form a solid electrolyte layer;

[0015] pressing a composite positive electrode material on one side of the solid electrolyte layer to form a positive electrode, and pressing a composite negative electrode material on the other side of the solid electrolyte layer to form a silicon-based negative electrode, thereby obtaining the pre-prepared solid-state battery.

[0016] In some embodiments, the composite negative electrode material comprises a silicon negative electrode material, a second solid-state electrolyte material, and a first conductive agent.

[0017] Optionally, the mass ratio of the silicon negative electrode material, the second solid-state electrolyte material, and the conductive agent is 50-100:0-45:0-10.

[0018] In some embodiments, the silicon negative electrode material comprises silicon.

[0019] In some embodiments, the silicon negative electrode material has a volume average particle size Dv50 of 0.1-10 μm.

[0020] In some embodiments, the composite positive electrode material comprises a positive electrode active material, a third solid-state electrolyte material, and a second conductive agent.

[0021] Optionally, the mass ratio of the positive electrode active material, the third solid-state electrolyte material, and the second conductive agent is 60-85:15-35:1-10.

[0022] In a second aspect, the present application provides a silicon-based negative electrode solid-state battery, which is prepared by the method for preparing a silicon-based negative electrode solid-state battery according to the first aspect.

[0023] Compared with the prior art, the present application has at least the following beneficial effects:

[0024] The pre-prepared solid-state battery is subjected to secondary pressing treatment after the first charging. Since the silicon-based negative electrode forms lithium-silicon alloy by embedding lithium during the charging process, its modulus is significantly reduced compared with the original silicon material, and it is easy to deform during the pressing process, thereby effectively improving the interface contact condition of the silicon-based negative electrode. In addition, the silicon material will change from a crystalline state to an amorphous state after the first embedding of lithium, and its stress-strain relationship changes from anisotropy to isotropy. Therefore, the structure of the silicon-based negative electrode after secondary pressing will be more stable, thereby effectively improving the electrochemical performance of the silicon-based negative electrode solid-state battery. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 The figure is a comparison chart of the discharge specific capacity of the silicon-based negative electrode solid-state battery in Example 1 and Comparative Example 1 of the present application. DETAILED DESCRIPTION

[0026] The application will be described in further detail with reference to the embodiments and examples, which are presented for illustration only and should not be construed in any way to limit the scope of the application. The present application can be carried out in many different ways and is not limited to the embodiments and examples described herein. Rather, the present application covers all technical equivalents that fall within the scope of the present application. Furthermore, in the following description, numerous specific details are given to provide a thorough understanding of the present application. However, it will be apparent that the present application can be practiced without one or more of these specific details.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description herein is for describing particular embodiments only and is not intended to be limiting of the application.

[0028] In the present application, "optionally", "optional" and "alternatively" mean optional, i.e. selected from either of the two parallel schemes "with" or "without". If there are multiple "optionally" in a technical solution, each "optionally" is independent of each other, unless otherwise specified, and there is no contradiction or mutual restriction.

[0029] In the present application, the terms "first", "second", etc. in the "first aspect", "second aspect", etc. are only for the purpose of description, and cannot be understood as indicating or implying relative importance or quantity, nor can it be understood as implicitly indicating the importance or quantity of the technical features indicated. Moreover, "first", "second", etc. only serve the purpose of non-exhaustive enumeration description, and should be understood as not constituting a closed limitation on the quantity.

[0030] In the present application, the technical features described in an open manner include both the closed technical solution consisting of the listed features and the open technical solution containing the listed features.

[0031] In the present application, when referring to a numerical interval (i.e. a numerical range), the distribution of the selectable values in the numerical interval is considered continuous and includes both numerical endpoints (i.e. the minimum and maximum values) of the numerical interval and every value between the two numerical endpoints, unless otherwise specified. When a numerical interval refers only to integers within the numerical interval, unless otherwise specified, the two endpoint integers and every integer between the two endpoints are considered to be directly enumerated. When multiple numerical ranges are provided to describe a characteristic or property, the numerical ranges can be combined. In other words, unless otherwise specified, numerical ranges disclosed in the present application are to be understood to include any and all sub-ranges considered therein and sub-ranges end-point inclusive. A "numerical interval" can be any quantitative interval, such as a numerical interval, a percentage interval, a ratio interval, etc.

[0032] All documents mentioned in this application are incorporated herein by reference as if each document were individually incorporated by reference. Unless otherwise indicated, the documents discussed in this application are incorporated by reference in their entirety, and for all purposes. When referring to documents in this application, the definitions of relevant technical features, terms, names, phrases, etc. in the cited documents are also incorporated by reference. When referring to documents in this application, examples and preferred modes of the relevant technical features cited are also incorporated by reference into this application, subject to the ability to implement this application. It should be understood that when the cited content conflicts with the description in this application, this application shall prevail or be modified adaptively according to the description in this application.

[0033] In the conventional technology, in order to improve the interface contact of the solid-state electrode, mainly the following methods are adopted: adding a binder, applying a high forming pressure in the electrode preparation stage, and applying a high operating pressure in the battery operation stage. For example, a high forming pressure (500 MPa~1500 MPa) is applied in the electrode preparation stage to reduce the porosity of the solid-state electrode as much as possible and to improve the contact between the electrode components. However, due to the irregular shape of the silicon particles and the difficulty of deformation, even if the forming pressure is as high as several hundred or even thousands of megapascals, the compaction density of the solid-state silicon-based negative electrode is difficult to further improve, resulting in a high tortuosity of ion and electron transport. In the subsequent lithium extraction process, the electrode structure will still change due to the expansion and contraction of silicon, further affecting the ion and electron transport path. Therefore, the above-mentioned methods are difficult to improve the electrochemical performance of the silicon-based negative electrode solid-state battery, especially the rate performance.

[0034] The first aspect of the present application provides a preparation method of a silicon-based negative electrode solid-state battery, the preparation method comprising:

[0035] Assembling the positive electrode, the solid electrolyte layer and the silicon-based negative electrode to obtain a pre-prepared solid-state battery;

[0036] performing a charge-discharge cycle on the pre-solid-state battery in a state of applying a first pressure, after the pre-solid-state battery is charged for the first time, performing a pressing treatment on the pre-solid-state battery in a state of applying a second pressure, the second pressure being greater than the first pressure;

[0037] continuing to perform the charge-discharge cycle on the pre-solid-state battery after the pressing treatment in the state of applying the first pressure, to obtain the silicon-based negative electrode solid-state battery.

[0038] The present application performs a secondary pressing treatment on the pre-solid-state battery after the first charge. During the charging process, lithium-silicon alloy is formed in the silicon-based negative electrode, and the modulus of the lithium-silicon alloy is significantly lower than that of the original silicon material, which is easy to deform during the pressing process, thereby effectively improving the interface contact of the silicon-based negative electrode. After the first lithium insertion, the silicon material changes from a crystalline state to an amorphous state, and the stress-strain relationship changes from anisotropy to isotropy. Therefore, the structure of the silicon-based negative electrode after the secondary pressing is more stable, thereby effectively improving the electrochemical performance of the silicon-based negative electrode solid-state battery.

[0039] In some embodiments, the ambient temperature during the charge-discharge cycle is 25°C to 60°C.

[0040] In some embodiments, the rate of the first charge of the pre-solid-state battery is 0.05C to 0.2C, for example, it can be 0.05C, 0.06C, 0.08C, 0.10C, 0.12C, 0.14C, 0.16C, 0.18C or 0.20C. The present application selects the first charge rate as above, which can promote the relatively uniform lithiation of the silicon-based negative electrode and ensure the stability of the electrode structure during the pressing treatment. If the charge rate is relatively high, it may lead to uneven lithiation in the thickness direction of the silicon-based negative electrode, thereby causing unstable electrode structure and affecting the effect of the pressing treatment.

[0041] In some embodiments, the state of charge of the pre-solid-state battery after the first charge is 30% to 100%, for example, it can be 30%, 40%, 50%, 60%, 70%, 80%, 90% or 100%. The present application selects the state of charge of the pre-solid-state battery after the first charge as above, which can promote the formation of lithium-silicon alloy with low modulus in the silicon-based negative electrode, thereby ensuring the effect of the pressing treatment. If the state of charge is relatively low, the amount of lithium-silicon alloy formed in the silicon-based negative electrode may be small, and the silicon-based negative electrode still contains a high content of silicon material, which cannot be deformed sufficiently during the pressing treatment, thereby failing to effectively improve the interface contact.

[0042] It can be understood that, if the state of charge of the pre-solid-state battery after the first charging is less than 100% in the present application, the pre-solid-state battery after the pressing treatment is continuously charged until the state of charge is 100%, and then the charging and discharging cycle is carried out. The charging and discharging rate and the cycle number in the subsequent charging and discharging cycle can be selected according to the formation operation of the silicon-based negative electrode solid-state battery. If the state of charge of the pre-solid-state battery after the charging is 100%, the pre-solid-state battery after the pressing treatment is discharged, and then the charging and discharging cycle is carried out. The charging and discharging rate and the cycle number in the subsequent charging and discharging cycle can be selected according to the formation operation of the silicon-based negative electrode solid-state battery. It should be noted that the pre-solid-state battery does not need to be charged during the pressing treatment in the present application.

[0043] It can be understood that, in one charging and discharging cycle, the charging rate and the discharging rate should be the same. That is, the charging rate of the pre-solid-state battery in the present application during the first charging is 0.05C~0.2C. Correspondingly, the discharging rate during the first discharging should also be 0.05C~0.2C, and be the same as the charging rate of the first charging.

[0044] In some embodiments, the first pressure is 1 MPa~200 MPa, for example, it can be 1 MPa, 10 MPa, 20 MPa, 40 MPa, 60 MPa, 80 MPa, 100 MPa, 120 MPa, 140 MPa, 160 MPa, 180 MPa or 200 MPa.

[0045] In some embodiments, the second pressure is 200 MPa~1500 MPa, for example, it can be 200 MPa, 300 MPa, 400 MPa, 500 MPa, 600 MPa, 700 MPa, 800 MPa, 900 MPa, 1000 MPa, 1100 MPa, 1200 MPa, 1300 MPa, 1400 MPa or 1500 MPa. The second pressure in the pressing treatment process is selected as above in the present application, on the one hand, to ensure that the lithium-silicon alloy can be fully deformed during the pressing process, and to avoid the effect of insufficient pressure on the pressing effect, on the other hand, to avoid the breaking of the positive electrode particles caused by excessive pressure.

[0046] In some embodiments, the time of the pressing treatment is 1 min~10 min, for example, it can be 1 min, 2 min, 3 min, 4 min, 5 min, 6 min, 7 min, 8 min, 9 min or 10 min.

[0047] It can be understood that the assembly method of the prefabricated solid-state battery can be adjusted according to the type of the silicon-based negative electrode solid-state battery. For example, the silicon-based negative electrode solid-state battery can also be a soft package type solid-state battery, and the solid-state battery can be assembled by pressing the anode, the cathode and the solid-state electrolyte film prepared in advance by a wet method or a dry method. The application does not make specific requirements and special limitations on the assembly method of the prefabricated solid-state battery.

[0048] In some embodiments, the assembly method of the prefabricated solid-state battery comprises:

[0049] pressing the first solid-state electrolyte material to form a solid electrolyte layer;

[0050] pressing a composite anode material on one side of the solid electrolyte layer to form an anode, and pressing a composite negative electrode material on the other side of the solid electrolyte layer to form a silicon-based negative electrode, thereby assembling the prefabricated solid-state battery.

[0051] In some embodiments, the composite negative electrode material comprises a silicon negative electrode material, a second solid-state electrolyte material and a first conductive agent.

[0052] Optionally, the mass ratio of the silicon negative electrode material, the second solid-state electrolyte material and the conductive agent is 50-100:0-45:0-10.

[0053] In some embodiments, the silicon negative electrode material comprises silicon.

[0054] In some embodiments, the volume average particle size Dv50 of the silicon negative electrode material is 0.1-10 μm, for example, it can be 0.1 μm, 0.2 μm, 0.5 μm, 0.8 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm or 10 μm.

[0055] In some embodiments, the composite anode material comprises an anode active material, a third solid-state electrolyte material and a second conductive agent.

[0056] Optionally, the mass ratio of the anode active material, the third solid-state electrolyte material and the second conductive agent is 60-85:10-35:1-10.

[0057] In some embodiments, the anode material can be selected according to the silicon-based negative electrode solid-state battery, for example, it can be LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2.

[0058] It can be understood that the materials of the first solid-state electrolyte, the second solid-state electrolyte and the third solid-state electrolyte in the present application can be selected according to the requirements of the silicon-based negative electrode solid-state battery, and the materials of the first solid-state electrolyte, the second solid-state electrolyte and the third solid-state electrolyte can be the same or different. For example, the first solid-state electrolyte, the second solid-state electrolyte and the third solid-state electrolyte all use Li6PS5Cl.

[0059] It can be understood that the first conductive agent and the second conductive agent in the present application can be selected according to the requirements of the silicon-based negative electrode solid-state battery, and the first conductive agent and the second conductive agent can be the same or different. For example, the first conductive agent and the second conductive agent are both conductive carbon. Alternatively, the conductive carbon can be Vapor Grown Carbon Fiber (VGCF).

[0060] Exemplarily, a preparation method of the above-mentioned solid-state battery is provided, comprising the following steps:

[0061] The first solid-state electrolyte material is pressed to form a solid electrolyte layer;

[0062] A composite positive electrode material is used to press a positive electrode on one side of the solid electrolyte layer, and a composite negative electrode material is used to press a silicon-based negative electrode on the other side of the solid electrolyte layer, so as to assemble the pre-prepared solid-state battery;

[0063] The pre-prepared solid-state battery is subjected to a first charging under the condition of applying a first pressure, and the first charging rate is 0.05C~0.2C. The pre-prepared solid-state battery with a state of charge of 30%~100% after the first charging is subjected to a pressing treatment under the condition of applying a second pressure, the first pressure is 1MPa~200MPa, and the second pressure is 200MPa~1500MPa;

[0064] The pre-prepared solid-state battery after the pressing treatment is continuously subjected to a charging and discharging cycle under the condition of applying the first pressure, so as to prepare a silicon-based negative electrode solid-state battery.

[0065] The second aspect of the present application provides a silicon-based negative electrode solid-state battery, which is prepared by using the preparation method of the silicon-based negative electrode solid-state battery as described in the first aspect.

[0066] In some embodiments, the silicon-based negative electrode solid-state battery comprises positive electrodes and silicon-based negative electrodes which are alternately and laminatedly arranged, and further comprises a solid electrolyte layer between the positive electrodes and the silicon-based negative electrodes.

[0067] In some embodiments, the thickness of the positive electrode is 20μm~200μm.

[0068] In some embodiments, the thickness of the silicon-based negative electrode is 5μm~50μm.

[0069] In some embodiments, the thickness of the solid electrolyte layer is 20 pm to 600 pm.

[0070] Further, the present application also provides a power consuming device comprising the above-mentioned silicon-based negative electrode solid-state battery.

[0071] The above-mentioned power consuming device can include any device or apparatus driven by a secondary battery, such as a mobile phone, a notebook computer, an electric vehicle, a ship, a satellite, an energy storage device, a smart home appliance, and the like, but is not limited thereto.

[0072] The embodiments of the present application will be described in detail below with reference to the examples. It should be understood that these examples are only used to illustrate the present application and are not used to limit the scope of the present application. The experimental methods not specified in the following examples are preferably referred to the guidelines given in the present application, and can also be carried out according to the experimental manuals or conventional conditions in the art, or according to the conditions suggested by the manufacturers, or according to the known experimental methods in the art.

[0073] Example 1

[0074] Silicon with a volume average particle size of 3 pm, sulfide electrolyte Li6PS5Cl and conductive carbon VGCF were weighed according to a mass ratio of 60:35:5, then added to a mortar and mixed by manual grinding for 30 min to obtain a composite negative electrode material; active material NCM111, sulfide electrolyte Li6PS5Cl and conductive carbon VGCF were weighed according to a mass ratio of 70:25:5, then added to a mortar and mixed by manual grinding for 20 min to obtain a composite positive electrode material.

[0075] A Si|Li6PS5Cl|NCM full solid-state battery was assembled using a mold with a diameter of 10 mm. First, 85 mg of sulfide electrolyte Li6PS5Cl powder was weighed and added to the mold and leveled, and then pressed at a pressure of 300 MPa for 2 min to obtain a solid electrolyte layer. Then, 44.0 mg of the above-mentioned composite positive electrode material was weighed and evenly spread on one side of the solid electrolyte layer, and then pressed at a pressure of 300 MPa for 2 min to form a positive electrode. Then, 2.7 mg of the above-mentioned composite negative electrode material was weighed and evenly spread on the other side of the solid electrolyte layer, and then pressed at a pressure of 900 MPa for 2 min to form a silicon-based negative electrode. Finally, a stainless steel clamp was used to apply a first pressure to the mold battery, and the first pressure was 100 MPa, to obtain a pre-prepared solid-state battery for the next step of electrochemical testing. The entire assembly process was carried out in an argon-filled glove box with an environment requirement of water content <0.01 ppm and oxygen content <0.01 ppm.

[0076] The assembled pre-solid-state battery was transferred to a thermostat with an ambient temperature of 45°C and left to stand for 12 h, after which the pre-solid-state battery was subjected to rate charge-discharge testing using a Neware battery testing system, wherein the first 3 cycles were subjected to charge-discharge at 0.1C, and after the first charge to 4.2V at 0.1C (i.e. a state of charge of 100%), the pre-solid-state battery was removed from the stainless steel clamp, re-pressed at a second pressure for 2 min, the second pressure being 900 MPa, and then the stainless steel clamp was used again to apply a first pressure to the pre-solid-state battery, the first pressure being 100 MPa, and the pre-solid-state battery was returned to the thermostat, left to stand for 30 min, and then discharged to 2.4V at 0.1C, and then 2 more cycles were performed at 0.1C, completing the formation process, and then 3 cycles were performed at 0.2C, 0.5C, 1C and 2C, respectively.

[0077] Example 2

[0078] A silicon-based negative electrode solid-state battery was prepared according to the method of Example 1, except that the first charge rate was 0.3C.

[0079] Example 3

[0080] A silicon-based negative electrode solid-state battery was prepared according to the method of Example 1, except that the second pressure in the pressing treatment was 100 MPa.

[0081] Example 4

[0082] A silicon-based negative electrode solid-state battery was prepared according to the method of Example 1, except that the second pressure in the pressing treatment was 1600 MPa.

[0083] Example 5

[0084] A silicon-based negative electrode solid-state battery was prepared according to the method of Example 1, except that the state of charge of the pre-solid-state battery after charging was 20%.

[0085] Comparative Example 1

[0086] A silicon-based negative electrode solid-state battery was prepared according to the method of Example 1, except that no pressing treatment was performed during the charge-discharge cycle.

[0087] The discharge specific capacity and initial efficiency test results of the silicon-based negative electrode solid-state batteries in the above examples and Comparative Example 1 during the charge-discharge cycle at 0.1C, 0.2C, 0.5C, 1C and 2C are shown in Table 1, wherein the comparison of the discharge specific capacity of Example 1 and Comparative Example 1 is shown in Figure 1 .

[0088] Table 1

[0089]

[0090] From the above table, it can be seen that:

[0091] (1) Compared with Example 2, it can be seen that the application controls the charge rate of the pre-solid-state battery before the pressing treatment, which can promote the relatively uniform lithiation of the silicon-based negative electrode and ensure the stability of the electrode structure during the pressing treatment. If the charge rate is relatively high, it may cause the problem of uneven lithiation of the silicon-based negative electrode in the thickness direction, thereby causing the electrode structure to be unstable and affecting the effect of the pressing treatment.

[0092] (2) Compared with Examples 3-4, it can be seen that the application controls the second pressure in the pressing treatment, which on the one hand ensures that the lithium-silicon alloy can deform sufficiently during the pressing process, avoiding the insufficient pressure affecting the pressing effect, and on the other hand avoids the positive electrode particles being broken due to excessive pressure.

[0093] (3) Compared with Example 5, it can be seen that the application can promote the formation of lithium-silicon alloy with low modulus inside the silicon-based negative electrode, thereby ensuring the effect of the pressing treatment. If the state of charge is relatively low, it may cause the amount of lithium-silicon alloy formed in the silicon-based negative electrode to be small, and the silicon-based negative electrode still contains a high content of silicon material, which cannot deform sufficiently during the pressing treatment, and cannot effectively improve the interface contact problem.

[0094] (4) Compared with Comparative Example 1, it can be seen that the application performs a second pressing treatment on the pre-solid-state battery after the first charging. Since the silicon-based negative electrode forms lithium-silicon alloy during the charging process, its modulus is significantly reduced compared with the original silicon material, which is easy to deform during the pressing process, thereby effectively improving the interface contact of the silicon-based negative electrode. In addition, the silicon material will change from a crystalline state to an amorphous state after the first lithium intercalation, and its stress-strain relationship changes from anisotropy to isotropy, so the structure of the silicon-based negative electrode after the second pressing will be more stable, thereby effectively improving the electrochemical performance of the silicon-based negative electrode solid-state battery.

[0095] The technical features of the above-described embodiments can be combined arbitrarily. To make the description concise, all possible combinations of the technical features in the above-described embodiments are not described, but as long as the combinations of the technical features do not exist contradictory, they should be considered as the scope of the present application.

[0096] The above-described embodiments only express several implementation manners of the application, and the description is relatively specific and detailed, but it should not be understood as a limitation on the scope of the application. It should be pointed out that for ordinary skilled persons in the art, without departing from the concept of the application, a number of modifications and improvements can be made, which are all within the protection scope of the application. Therefore, the protection scope of the application should be subject to the appended claims.

Claims

1. A method for preparing a silicon-based negative solid-state battery, characterized in that, The preparation method comprises: Assembling a positive electrode, a solid electrolyte layer and a silicon-based negative electrode to obtain a pre-prepared solid-state battery; The pre-prepared solid-state battery is subjected to a charge-discharge cycle under a state of applying a first pressure, and after the pre-prepared solid-state battery is charged for the first time, the pre-prepared solid-state battery is subjected to a pressing treatment under a state of applying a second pressure, the second pressure being greater than the first pressure; wherein the state of charge of the pre-prepared solid-state battery after the first time is 30% to 100%, the first pressure is 1 MPa to 200 MPa, and the second pressure is 200 MPa to 1500 MPa; The pre-prepared solid-state battery after the pressing treatment is subjected to a charge-discharge cycle under a state of applying the first pressure to obtain the silicon-based negative electrode solid-state battery.

2. The method for preparing a silicon-based anode solid-state battery as described in claim 1, characterized in that, The rate of the first time of charging the pre-prepared solid-state battery is 0.05C to 0.2C.

3. The method for preparing a silicon-based anode solid-state battery as described in claim 1, characterized in that, The pressing treatment time is 1 minute to 10 minutes.

4. The method of producing a silicon-based negative solid-state battery according to any one of claims 1 to 3, wherein The assembly method of the pre-prepared solid-state battery comprises: Pressing a first solid electrolyte material to form a solid electrolyte layer; Using a composite positive electrode material to press a positive electrode on one side of the solid electrolyte layer, and using a composite negative electrode material to press a silicon-based negative electrode on the other side of the solid electrolyte layer to obtain the pre-prepared solid-state battery.

5. The method for preparing a silicon-based anode solid-state battery as described in claim 4, characterized in that, The composite negative electrode material comprises a silicon negative electrode material, a second solid electrolyte material and a first conductive agent.

6. The method of claim 5, wherein the silicon-based negative solid-state battery is prepared by the steps of: The mass ratio of the silicon negative electrode material, the second solid electrolyte material and the conductive agent is 50 to 100: 0 to 45: 0 to 10.

7. The method for preparing a silicon-based anode solid-state battery as described in claim 5, characterized in that, The silicon negative electrode material satisfies at least one of the following conditions: (1) The silicon negative electrode material comprises silicon; (2) The volume average particle size Dv50 of the silicon negative electrode material is 0.1 μm to 10 μm.

8. The method for preparing a silicon-based anode solid-state battery as described in claim 4, characterized in that, The composite positive electrode material comprises a positive electrode active material, a third solid electrolyte material and a second conductive agent.

9. The method of claim 8, wherein the silicon-based negative solid-state battery is prepared by the steps of: 5 preparing a silicon-based negative electrode; preparing a solid electrolyte; and preparing a solid electrolyte interface layer on the surface of the silicon-based negative electrode. The mass ratio of the positive electrode active material, the third solid electrolyte material and the second conductive agent is 60 to 85: 15 to 35: 1 to 10.

10. A silicon-based negative solid-state battery, characterized by, The silicon-based negative electrode solid-state battery is prepared by the preparation method of the silicon-based negative electrode solid-state battery according to any one of claims 1 to 9.

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