Silicon negative electrode and preparation method thereof, and all-solid-state lithium ion battery and preparation method thereof

Abstract

The application provides a silicon negative electrode and a preparation method thereof, and a full-solid-state lithium ion battery and a preparation method thereof. The silicon negative electrode comprises a negative electrode current collector and a silicon active layer formed on the surface of the negative electrode current collector, wherein the silicon active layer comprises a plurality of silicon lithium intercalation regions distributed at intervals, and the gaps between the plurality of silicon lithium intercalation regions are distributed in the form of spots at intervals on the surface of the silicon active layer. The gaps between the plurality of silicon lithium intercalation regions of the silicon active layer in the silicon negative electrode of the embodiment of the application can provide accommodation space for the silicon which generates volume expansion when intercalating lithium, so that the cracking and peeling of the silicon active layer when deintercalating lithium can be avoided, and the cycle life of the full-solid-state lithium ion battery is improved.

Description

Technical Field

[0001] This invention relates to the field of battery technology, specifically to a silicon anode and its preparation method, as well as an all-solid-state lithium-ion battery and its preparation method. Background Technology

[0002] Silicon anodes boast a theoretical specific capacity of up to 4200 mAh / g, more than ten times that of traditional graphite anodes, promising a significant increase in the energy density of next-generation lithium-ion batteries. However, silicon anodes have a fatal flaw: silicon undergoes a volume expansion of over 300% during lithium intercalation. This is because lithium-silicon alloys form after lithium intercalation, resulting in a massive volume change. In liquid lithium-ion batteries, this change leads to the continuous formation and rupture of the SEI film, causing loss of active lithium and a rapid decrease in capacity. In contrast to liquid lithium-ion batteries, all-solid-state lithium-ion batteries use a solid electrolyte instead of a liquid electrolyte, so only the surface layer of the solid electrolyte comes into contact with the surface of the anode, reducing the repeated formation of the solid electrolyte interface phase.

[0003] Currently, to alleviate silicon expansion, most applications are based on the combination of nano-silicon and carbon skeleton. However, this is not applicable to all-solid-state lithium-ion batteries because the carbon skeleton cannot conduct lithium ions, and the silicon content in this silicon-carbon anode is low, which cannot bring out the high specific capacity of silicon. In addition, the carbon skeleton may react with the solid electrolyte, which will reduce the energy density of the all-solid-state battery and accelerate the cycle life decay. Summary of the Invention

[0004] In view of this, the present invention provides a silicon anode that can prevent the silicon active layer from cracking and falling off during lithium insertion / extraction.

[0005] The present invention also provides a method for preparing a silicon anode.

[0006] The present invention also provides an all-solid-state lithium-ion battery.

[0007] The present invention also provides a method for preparing an all-solid-state lithium-ion battery.

[0008] According to a first aspect of the present invention, the silicon anode comprises:

[0009] Negative current collector; and

[0010] The silicon active layer formed on the surface of the negative electrode current collector,

[0011] The silicon active layer includes a plurality of spaced-apart lithium intercalation regions, and the gaps between the plurality of lithium intercalation regions are distributed in a spaced-apart spot-like pattern on the surface of the silicon active layer.

[0012] Furthermore, the area of ​​the gap in the silicon active layer accounts for 20%-70%.

[0013] Furthermore, the negative electrode current collector is selected from one or more of copper foil, carbon-coated copper foil, and stainless steel foil.

[0014] The method for preparing a silicon anode according to a second aspect embodiment of the present invention includes the following steps:

[0015] S1 provides the negative electrode current collector in the reactor;

[0016] S2, a deposition layer is formed on the surface of the negative electrode current collector in step S1;

[0017] S3, etching is performed on the surface of the deposited layer in step S2 to obtain a plurality of spaced-apart lithium intercalation regions, and the gaps between the plurality of lithium intercalation regions are distributed in a spaced-apart spot-like pattern on the surface of the silicon active layer.

[0018] Furthermore, in step S1, the temperature inside the reactor is 500℃-850℃, and the pressure is 300Pa-2000Pa.

[0019] Further, in step S2, the negative electrode current collector from step S1 is exposed to a silicon-containing vapor precursor, heated to cause the vapor precursor to undergo pyrolysis, and deposited on the surface of the negative electrode current collector to form the deposition layer.

[0020] Furthermore, in step S2, the negative electrode current collector is exposed to the gas phase precursor for 1 min to 500 min, and the thickness of the deposited layer is 20 nm to 10 μm.

[0021] Furthermore, the gaseous precursor is a silane, a silane derivative, or a mixture thereof.

[0022] Further, step S3 includes:

[0023] S31, a layer of photoresist is uniformly coated on the current collector with deposited silicon material, and the photoresist solvent is evaporated by heating;

[0024] S32, the photoresist is exposed and polymerized using a pre-designed mask, then the non-polymerized photoresist is removed, and the photoresist is dried again;

[0025] S33, use an etching solution to etch away the silicon layer that is not covered by photoresist;

[0026] S34. The patterned silicon anode sheet is obtained by washing away the photoresist with solvent and drying it.

[0027] According to a third aspect of the present invention, an all-solid-state lithium-ion battery includes a positive current collector, a composite positive electrode, a solid electrolyte layer, and a silicon negative electrode stacked sequentially, wherein the silicon negative electrode is the aforementioned silicon negative electrode.

[0028] The method for preparing an all-solid-state lithium-ion battery according to a fourth aspect of the present invention includes the following steps:

[0029] S100, providing a silicon anode, wherein the silicon anode is prepared by the method described above;

[0030] S200 provides a solid electrolyte layer;

[0031] S300 provides a composite cathode;

[0032] S400: The positive current collector, the composite positive electrode, the solid electrolyte layer, and the silicon negative electrode are stacked in sequence and pressed to obtain a battery cell;

[0033] S500, based on the cell, is packaged to obtain the all-solid-state lithium-ion battery.

[0034] The above-described technical solution of the present invention has at least one of the following beneficial effects:

[0035] According to an embodiment of the present invention, a silicon anode has a silicon active layer formed on the surface of the anode current collector. The silicon active layer includes a plurality of spaced-apart lithium intercalation regions, and the gaps between the plurality of lithium intercalation regions are distributed in a spaced-apart spot-like pattern on the surface of the silicon active layer. That is, there are gaps between the plurality of lithium intercalation regions of the silicon active layer, which provides a space for the silicon to expand in volume during lithium intercalation, thereby preventing the silicon active layer from cracking and falling off during lithium intercalation and deintercalation, and improving the cycle life of the all-solid-state lithium-ion battery. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the structure of a silicon anode according to an embodiment of the present invention;

[0037] Figure 2 This is a schematic diagram of the silicon anode structure according to another embodiment of the present invention;

[0038] Figure 3 This is a flowchart illustrating the method for preparing the silicon anode according to an embodiment of the present invention;

[0039] Figure 4 This is a schematic diagram of the structure of an all-solid-state lithium-ion battery according to an embodiment of the present invention;

[0040] Figure 5 This is a flowchart illustrating the preparation method of an all-solid-state lithium-ion battery according to an embodiment of the present invention.

[0041] Figure reference numerals: 1. Silicon anode; 10. Anode current collector; 11. Silicon active layer; 111. Silicon lithium intercalation region; 112. Gap; 2. Solid electrolyte layer; 30. Composite cathode; 31. Cathode current collector. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention are within the scope of protection of the present invention.

[0043] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms "an" or "a" and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms "connected" or "linked" and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up," "down," "left," "right," etc., are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship also changes accordingly.

[0044] The silicon anode 1 of the first aspect embodiment of the present invention will now be described in detail.

[0045] To provide sufficient space for the silicon to expand during lithium intercalation, gaps 112 are formed between multiple lithium intercalation regions 111 in the silicon active layer 11 of the silicon anode 1. These gaps 112 are distributed in a spaced-apart, spot-like pattern on the surface of the silicon active layer 11, thus buffering the lateral expansion of the lithium intercalation layer. Figure 1 , Figure 2 As shown, the silicon anode 1 includes: a negative electrode current collector 10; and a silicon active layer 11 formed on the surface of the negative electrode current collector 10. The silicon active layer 11 includes a plurality of spaced-apart lithium-intercalation regions 111, and the gaps 112 between the plurality of lithium-intercalation regions 111 are distributed in a spaced-apart spot-like pattern on the surface of the silicon active layer 11. That is, a silicon active layer 11 is formed on the surface of the negative electrode current collector 10, the silicon active layer 11 includes a plurality of spaced-apart lithium-intercalation regions 111, and gaps 112 exist between the plurality of lithium-intercalation regions 111, with the gaps 112 distributed in a spaced-apart spot-like pattern on the surface of the silicon active layer 11. The gaps 112 can be as follows: Figure 1 The enclosed region shown can be, for example, a circle, triangle, square, polygon, or irregular shape; it can also be as follows: Figure 2 The open area shown can be, for example, a square with open ends, such as... Figure 2 As shown, the gaps 112 are alternately spaced from the lithium intercalation regions 111. The shape of the gaps 112 is preferably a regular circle or square to facilitate design and layout. The gap 112 structure between the plurality of lithium intercalation regions 111 of the silicon anode 1 in this embodiment can provide a space for the silicon to expand in volume during lithium intercalation, preventing the silicon active layer 11 from cracking and falling off during lithium intercalation and deintercalation, thereby improving the cycle life of the all-solid-state lithium-ion battery.

[0046] Furthermore, the area ratio of gap 112 in the silicon active layer 11 is 20%-70%. That is, as... Figure 1 , Figure 2 As shown, the area ratio of the gap 112 in the silicon active layer 11 can be, for example, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, or 70%. Under this area ratio, on the one hand, when silicon expands in volume due to lithium intercalation, the gap 112 can provide enough space to accommodate the expanded silicon, thereby preventing the silicon active layer 11 from cracking and falling off, and further improving the cycle life of the all-solid-state lithium-ion battery; on the other hand, more silicon lithium intercalation regions 111 can be formed on the silicon anode 1, ensuring better battery performance. If the area ratio of the gap 112 is greater than 70%, the silicon lithium intercalation region 111 formed on the limited negative electrode current collector 10 will be relatively reduced, thereby reducing the specific capacity of the silicon negative electrode 1 and affecting the performance of the battery. If the area ratio of the gap 112 is less than 20%, the gap 112 between any two adjacent silicon lithium intercalation regions 111 will be smaller. When silicon expands in volume due to lithium intercalation, the smaller gap 112 may not be able to accommodate the expanded silicon, which will make the silicon active layer 11 risk cracking and falling off when lithium is extracted, reducing the cycle life of the all-solid-state battery.

[0047] Furthermore, the negative electrode current collector 10 is selected from one or more of copper foil, carbon-coated copper foil, and stainless steel foil. That is to say, based on a comprehensive consideration of material performance and cost, one or more of copper foil, carbon-coated copper foil, and stainless steel foil can be selected as the negative electrode current collector 10.

[0048] The following is combined Figure 3 The method for preparing the silicon anode 1 according to an embodiment of the present invention includes the following steps:

[0049] S1 provides a negative electrode current collector 10 in the reactor;

[0050] S2, a deposition layer is formed on the surface of the negative electrode current collector 10 in step S1;

[0051] S3, etching is performed on the surface of the deposited layer in step S2 to obtain a plurality of spaced-apart lithium intercalation regions 111, and the gaps 112 between the plurality of lithium intercalation regions 111 are spaced-apart spot-like distributions on the surface of the silicon active layer 11.

[0052] In other words, such as Figure 3 As shown, a negative electrode current collector 10 is first provided and placed in a reactor. Then, a deposition layer is formed on the surface of the negative electrode current collector 10. In step S3, the deposition layer surface in step S2 is etched using an etching method to obtain a plurality of silicon lithium intercalation regions 111 that are spaced apart and have gaps 112. The plurality of gaps 112 are distributed in a spaced-apart spot pattern on the surface of the silicon active layer 11. That is, by forming gaps 112 between the plurality of silicon lithium intercalation regions 111, the gaps 112 can provide a space for the silicon that expands in volume during lithium intercalation, thereby preventing the silicon active layer 11 from cracking and falling off during lithium intercalation and improving the cycle life of the all-solid-state lithium-ion battery.

[0053] The following sections will provide a detailed explanation of S1-S3.

[0054] First, step S1 is explained, which involves providing the negative electrode current collector 10 in the reactor.

[0055] In some implementations, the temperature and pressure within the reactor can be controlled to promote silicon deposition on the surface of the negative electrode current collector 10.

[0056] Specifically, the temperature inside the reactor is 500℃-850℃, and the pressure is 300Pa-2000Pa. That is, by controlling and adjusting the temperature and pressure inside the reactor, silicon deposition on the surface of the negative electrode current collector 10 can be promoted, forming a silicon active layer 11 of the desired thickness on the negative electrode current collector 10 to ensure the overall performance of the battery. The temperature inside the reactor can be, for example, 500℃, 600℃, 700℃, or 850℃, and the pressure inside the reactor can be, for example, 300Pa, 600Pa, 900Pa, 1200Pa, 1500Pa, 1800Pa, or 2000Pa. It is worth noting that as the temperature and pressure inside the reactor increase, silicon deposition on the surface of the negative electrode current collector 10 can be further promoted, increasing the deposition efficiency. However, this promoting effect is not infinitely enhanced. Setting the temperature to 500℃-850℃ and the pressure to 300Pa-2000Pa is based on a comprehensive consideration of production cost and deposition efficiency.

[0057] Next, step S2, which is the formation of the deposition layer, will be explained.

[0058] In some embodiments, the negative electrode current collector 10 from step S1 is exposed to a silicon-containing vapor precursor, heated to cause pyrolysis of the vapor precursor, and deposited on the surface of the negative electrode current collector 10 to form a deposition layer. That is, by heating at high temperature to cause pyrolysis of the vapor precursor, the negative electrode current collector 10 can be exposed to the pyrolyzed vapor precursor at a temperature of 600°C and a pressure of 800 Pa, thereby forming a deposition layer on the surface of the negative electrode current collector 10 through chemical deposition.

[0059] Specifically, the exposure time of the negative electrode current collector 10 to the gas phase precursor is 1 min to 500 min, and the thickness of the deposited layer is 20 nm to 10 μm. That is, by controlling and adjusting the exposure time of the negative electrode current collector 10 to the gas phase precursor, a nanoscale or micrometer-scale deposited layer can be formed on the negative electrode current collector 10. A suitable thickness of deposited layer means that a silicon active layer 11 of suitable thickness can be obtained, thereby improving the interfacial contact characteristics between the silicon active layer 11 and the negative electrode current collector 10. Furthermore, controlling the thickness of the silicon lithium intercalation layer also helps to form gaps 112 between multiple silicon lithium intercalation regions 111, improving production efficiency. For example, if the exposure time of the negative electrode current collector 10 to the gas phase precursor is also 25 min, a micrometer-scale deposited layer with a thickness of 5 μm can be formed under conditions of 600 °C and 800 Pa.

[0060] In some embodiments, the gas-phase precursor is a silane, a silane derivative, or a mixture thereof. That is, using silicon-containing silanes, silane derivatives, or mixtures thereof, a silicon active layer 11 can be deposited on the surface of the negative electrode current collector 10. Furthermore, using silanes or silane derivatives as gas-phase precursors allows the byproducts CO2 and H2O generated during the deposition process to be rapidly carried away from the surface of the negative electrode current collector 10 by an inert gas, further promoting silicon deposition on the surface of the negative electrode current collector 10 and improving deposition efficiency.

[0061] Next, step S3 will be described, which involves forming a plurality of spaced-apart lithium intercalation regions 111 with gaps 112.

[0062] In some embodiments, the etching method may include the following steps: S31, uniformly coating a layer of photoresist on the current collector with deposited silicon material, and heating to evaporate the photoresist solvent; S32, exposing and polymerizing the photoresist through a pre-designed mask, then removing the non-polymerized photoresist and drying it again; S33, etching away the silicon layer not covered by the photoresist with an etching solution; S34, washing away the photoresist with a solvent and drying to obtain a patterned silicon anode electrode.

[0063] According to a third aspect embodiment of the present invention, an all-solid-state lithium-ion battery includes a positive electrode current collector 31, a composite positive electrode 30, a solid electrolyte layer 2, and a silicon negative electrode 1 stacked sequentially, wherein the silicon negative electrode is the aforementioned silicon negative electrode. That is, the distribution of the silicon lithium intercalation regions 111 and gaps 112 in the silicon active layer 11 of the silicon negative electrode 1 described in the first aspect embodiment, as well as the area ratio of the gaps 112, can all be applied to the all-solid-state lithium-ion battery of the third aspect embodiment of the present invention. For the sake of brevity, repeated descriptions are omitted here.

[0064] The following is combined Figure 4 The method for preparing an all-solid-state lithium-ion battery according to an embodiment of the present invention includes the following steps:

[0065] S100, a silicon anode 1 is provided, which is prepared by the above method;

[0066] S200, providing a solid electrolyte layer 2;

[0067] S300 provides a composite cathode 30;

[0068] S400, the positive current collector 31, the composite positive electrode 30, the solid electrolyte layer 2, and the silicon negative electrode 1 are stacked in sequence and pressed to obtain the battery cell;

[0069] S500 is based on battery cells, which are then packaged to obtain an all-solid-state lithium-ion battery.

[0070] In other words, such as Figure 4 As shown, in step S100, the process parameters for forming the deposition layer and the process parameters for etching described in the preparation method of the silicon anode 1 according to the second aspect embodiment can be applied to the preparation method of the all-solid-state lithium-ion battery of the fourth aspect embodiment of the present invention.

[0071] The following sections will provide a detailed explanation of steps S200, S300, and S400.

[0072] First, step S200, namely the preparation of solid electrolyte layer 2, will be explained.

[0073] In some implementations, step S200 includes:

[0074] S210 provides solid electrolyte powder;

[0075] S220, fill the solid electrolyte powder from step S210 into the mold and press it at 200MPa-400MPa for 2min-30min to obtain solid electrolyte layer 2.

[0076] In other words, solid electrolyte powder can be added to a tableting mold and pressed at 200MPa-400MPa for 2-30 minutes to obtain a solid electrolyte membrane with a specific shape. The pressing pressure can be, for example, 200MPa, 300MPa, or 400MPa, and the pressing time can be, for example, 2 minutes, 10 minutes, 20 minutes, or 30 minutes. By using high-pressure pressing, a dense and homogeneous solid electrolyte membrane can be formed, improving the overall performance of the solid electrolyte membrane.

[0077] Further, in step S210, the solid electrolyte powder is selected from Li6PS5Cl and Li6PS5Cl. 0.5 Br 0.5 Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 Li 10 GeP2S 12 Li7P3S 11 mLi2S·nP2S5, LiPON, Li 10 SnP2S 12 The solid electrolyte can be one or more of LiS-SiS2, and in mLi2S·nP2S5, 70≤m≤100 and 0≤n≤30. The aforementioned solid electrolyte possesses high ionic conductivity and high reactivity, which can improve the actual conductivity of lithium ions in the solid electrolyte film, reduce the interfacial resistance between the cathode and the sulfide electrolyte layer, improve interfacial stability, and further enhance the interfacial contact characteristics of all-solid-state batteries.

[0078] Next, step S300, namely the preparation of composite cathode 30, will be explained.

[0079] In some implementations, step S300 includes:

[0080] S310 provides powder;

[0081] S320, the powder is coated onto one side of the solid electrolyte layer 2 in step S310, and pressed for 2 min-30 min under a pressure of 200MPa-400MPa to obtain the composite cathode 30.

[0082] In other words, powder is coated onto one side of the already pressed solid electrolyte layer 2, and then pressed for 2-30 minutes under a pressure of 200MPa-400MPa, thereby forming a composite positive electrode 30 on one side of the solid electrolyte layer 2. This high-pressure pressing method forms the composite positive electrode 30 on one side of the solid electrolyte layer 2. Pressing significantly reduces the interfacial resistance between the positive electrode active layer and the solid electrolyte layer 2, improving interfacial stability and further enhancing the interfacial contact characteristics of the all-solid-state battery. The pressing pressure can be, for example, 200MPa, 300MPa, or 400MPa, and the pressing time can be, for example, 2 minutes, 10 minutes, 20 minutes, or 30 minutes. By controlling the pressing pressure and time, a dense and homogeneous composite positive electrode 30 can be formed, improving the overall performance of the all-solid-state lithium-ion battery.

[0083] Furthermore, in step S310, the powder contains 60-100 parts by mass of a positive electrode active material coated with a coating material, 0-40 parts by mass of a sulfide electrolyte, and 0-10 parts by mass of a conductive agent. In other words, by adjusting and controlling the content of each component in the powder, the overall performance of the all-solid-state lithium-ion battery is further improved.

[0084] The coating material is selected from one or more of LiNbO3, Li3BO3, LiPO3, Li2ZrO3, Li2TiO3, and Al2O3. Using a coating material to coat the positive electrode active material is based on safety and battery performance considerations. The coating material can prevent side reactions on the electrode surface, protect the substrate, and reduce battery heat generation. Selecting one or more of LiNbO3, Li3BO3, LiPO3, Li2ZrO3, Li2TiO3, and Al2O3 as the coating material can effectively prevent side reactions on the electrode surface and further improve the overall performance of the all-solid-state lithium-ion battery.

[0085] The positive electrode active material is one or more ternary materials with a Ni content greater than 70%, and the general chemical formula of the positive electrode active material is LiNi. x Co y Mn z O2, where x≥0.7, y≥0, z≥0, and x+y+z=1. That is, LiNi x Co y Mn z O2, or lithium nickel cobalt manganese oxide, boasts advantages such as high specific capacity and low cost, and is capable of providing large currents. Furthermore, lithium nickel cobalt manganese oxide has an ideal crystal structure and low self-discharge, making it suitable as a positive electrode active material to further improve the overall performance of all-solid-state lithium-ion batteries.

[0086] The sulfide electrolyte is selected from Li6PS5Cl and Li6PS5Cl. 0.5Br 0.5 Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 Li 10 GeP2S 12 Li7P3S 11 mLi2S·nP2S5, LiPON, Li 10 SnP2S 12 The electrolyte can be one or more of LiS-SiS2, and in mLi2S·nP2S5, 70≤m≤100, 0≤n≤30. The aforementioned sulfide electrolyte possesses high ionic conductivity and high reactivity, which can improve the actual conductivity of lithium ions in the sulfide electrolyte, reduce the interfacial resistance between the cathode and the sulfide electrolyte layer, improve interfacial stability, and further enhance the interfacial contact characteristics of all-solid-state batteries.

[0087] The conductive agent is selected from one or more of carbon fiber (hereinafter sometimes abbreviated as VCGF), carbon nanotubes (hereinafter sometimes abbreviated as CNT), conductive carbon black (hereinafter sometimes abbreviated as SP), and graphene. That is to say, the conductive agent is one or more of VCGF, CNT, SP, and graphene. The above-mentioned conductive agents can accelerate the transport of ions and electrons and improve the charge and discharge performance of all-solid-state batteries.

[0088] Next, step S400, namely the preparation of the battery cell, will be explained.

[0089] In some embodiments, in step S400, the battery cell is pressed for 2 to 30 minutes under a pressure of 200 MPa to 400 MPa to obtain the battery cell.

[0090] In other words, such as Figure 5 As shown, the positive current collector 31, the composite positive electrode 30, the silicon active layer 11 of the silicon negative electrode 1, and the negative current collector 10 of the silicon negative electrode 1 are stacked in sequence. By optimizing and controlling the pressing process parameters of the cell, the cell is obtained, which further improves the overall performance of the all-solid-state lithium-ion battery.

[0091] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below.

[0092] The present invention will be further described in detail below with reference to the preparation of the composite positive electrode 30 and silicon negative electrode 1 of the all-solid-state battery in a specific embodiment.

[0093] Example 1

[0094] (I) Preparation of silicon anode 1

[0095] A silicon anode 1 was prepared by deposition and photolithography. Specifically, (1) a copper foil anode current collector 10 was placed in a reactor at a temperature of 600°C and a pressure of 800 Pa; (2) the copper foil was exposed to silane that was heated and produced pyrolysis for 25 min to form a deposition layer with a thickness of 5 μm; (3) the deposition layer was etched by etching to obtain multiple silicon lithium intercalation regions 111 that were spaced apart, and the gaps 112 between the multiple silicon lithium intercalation regions 111 were distributed in a spaced-apart spot pattern on the surface of the silicon active layer 11.

[0096] (II) Preparation of solid electrolyte layer 2

[0097] Solid electrolyte layer 2 was prepared by high pressure pressing. Specifically, (1) 100 mg of Li6PS5Cl solid electrolyte powder was first filled into the mold; (2) it was pressed at 300 MPa for 10 min to obtain solid electrolyte layer 2.

[0098] (III) Preparation of composite cathode 30

[0099] Composite cathode 30 was prepared using a high-pressure pressing process. Specifically, (1) 70 mg of Al2O3-coated LiNi 0.8 Co 0.1 Mn 0.1 O3 ternary single crystal cathode material, 30mg of Li6PS5Cl sulfide electrolyte, and 1.5mg of conductive agent VCGF are mixed evenly with a mortar or mixer to obtain powder; (2) the powder is added to one side of the solid electrolyte layer 2 and pressed at 300MPa for 10min to obtain composite cathode 30.

[0100] (iv) Preparation of battery cells and all-solid-state lithium-ion batteries

[0101] The positive current collector 31, composite positive electrode 30, solid electrolyte layer 2, and silicon negative electrode 1 are stacked in sequence and pressed for 10 minutes under a pressure of 300 MPa to obtain the battery cell of Example 1.

[0102] The all-solid-state lithium-ion battery of Example 1 is obtained by packaging the cell of Example 1.

[0103] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A silicon anode for use in an all-solid-state lithium-ion battery, characterized in that, The silicon anode comprises: Negative current collector; and The silicon active layer formed on the surface of the negative electrode current collector, The silicon active layer includes a plurality of spaced-apart lithium intercalation regions, and the gaps between the plurality of lithium intercalation regions are distributed in a spaced-apart spot-like pattern on the surface of the silicon active layer. The silicon active layer and the spaced, spot-like gaps are obtained by chemical vapor deposition on the surface of the negative electrode current collector. The silicon-containing vapor precursor is heated to pyrolyze and deposited to form a deposition layer, and the deposition layer surface is etched by etching.

2. The silicon anode according to claim 1, characterized in that, The gaps account for 20%-70% of the area of ​​the silicon active layer.

3. The silicon anode according to claim 1, characterized in that, The negative electrode current collector is selected from one or more of copper foil, carbon-coated copper foil, and stainless steel foil.

4. A method for preparing a silicon anode according to any one of claims 1 to 3, characterized in that, Includes the following steps: S1 provides the negative electrode current collector in the reactor; S2, the negative electrode current collector from step S1 is exposed to a silicon-containing vapor precursor by chemical vapor deposition, heated to cause the vapor precursor to pyrolyze, and deposited on the surface of the negative electrode current collector to form a deposition layer. S3, etching is performed on the surface of the deposited layer in step S2 to obtain a plurality of spaced-apart lithium intercalation regions, and the gaps between the plurality of lithium intercalation regions are distributed in a spaced-apart spot-like pattern on the surface of the silicon active layer.

5. The method according to claim 4, characterized in that, In step S1, the temperature inside the reactor is 500℃-850℃ and the pressure is 300Pa-2000Pa.

6. The method according to claim 4, characterized in that, In step S2, the negative electrode current collector is exposed to the gaseous precursor for 1 min to 500 min, and the thickness of the deposited layer is 20 nm to 10 μm.

7. The method according to claim 4, characterized in that, The gaseous precursor is a silane, a silane derivative, or a mixture thereof.

8. The method according to claim 4, characterized in that, Step S3 includes: S31, a layer of photoresist is uniformly coated on the current collector with deposited silicon material, and the photoresist solvent is evaporated by heating; S32, the photoresist is exposed and polymerized using a pre-designed mask, then the non-polymerized photoresist is removed, and the photoresist is dried again; S33, use an etching solution to etch away the silicon layer that is not covered by photoresist; S34. The patterned silicon anode sheet is obtained by washing away the photoresist with solvent and drying it.

9. A fully solid-state lithium-ion battery, characterized in that, It includes a positive current collector, a composite positive electrode, a solid electrolyte layer, and a silicon negative electrode stacked in sequence, wherein the silicon negative electrode is the silicon negative electrode according to any one of claims 1 to 3.

10. A method for preparing an all-solid-state lithium-ion battery, characterized in that, Includes the following steps: S100, providing a silicon anode, wherein the silicon anode is prepared by the method according to any one of claims 4-8; S200 provides a solid electrolyte layer; S300 provides a composite cathode; S400: The positive current collector, the composite positive electrode, the solid electrolyte layer, and the silicon negative electrode are stacked in sequence and pressed to obtain a battery cell; S500, based on the cell, is packaged to obtain the all-solid-state lithium-ion battery.

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