Negative pole piece, preparation method thereof and all-solid-state battery

Abstract

The invention relates to the technical field of batteries, in particular to a negative pole piece, a preparation method thereof and an all-solid-state battery. The invention provides a negative pole piece. The negative pole piece comprises a negative active material, a solid electrolyte, a conductive agent and a binder, wherein the solid electrolyte is distributed in the negative pole piece in a cylindrical form. According to the negative pole piece, through the design of the specific structure of the negative pole piece, efficient utilization of the solid electrolyte is achieved, and higher energy density, higher magnification and longer cycle performance are achieved on the basis that the adding amount of the solid electrolyte in the negative pole piece is low.

Description

Technical Field

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

[0002] All-Solid-State Lithium Batteries (ASSLBs), with their leak-proof and flame-retardant solid electrolytes and the potential for ultra-high energy density improvement brought by the integrated "positive electrode-electrolyte-negative electrode" structure, are widely recognized as a revolutionary technology for overcoming the safety hazards and energy density bottlenecks of traditional liquid electrolyte lithium-ion batteries, and have broad application prospects in electric vehicles, drones, and other fields. As the core support for the performance of all-solid-state batteries, silicon-based anodes, with their ultra-high theoretical specific capacity of 4200 mAh / g (approximately 10 times that of commercial graphite anodes), have become ideal candidate materials for achieving the high energy density target of all-solid-state batteries.

[0003] However, the practical application of silicon-based anodes in all-solid-state batteries is limited by the dual challenges of the solid-solid interface and ion transport. On the one hand, there is a significant chemical-mechanical incompatibility between silicon and solid electrolytes. Silicon has a large Young's modulus, and its volume expansion during lithiation can easily lead to electrode structure collapse and interface delamination. Simultaneously, silicon has poor ion conductivity; when the electrode reaches a certain thickness, the ion transport hysteresis effect becomes significant, resulting in substantial battery polarization. To alleviate these problems, existing technologies generally employ a method of directly adding a certain amount of solid electrolyte to the silicon anode electrode formulation. This solid electrolyte constructs a continuous ion transport path, while simultaneously improving the solid-solid interface contact state between silicon and the electrolyte, and reducing interfacial impedance.

[0004] However, the aforementioned conventional addition methods contain irreconcilable technical contradictions that severely restrict the improvement of the overall performance of all-solid-state batteries. First, solid electrolytes are inactive materials; their addition to the negative electrode directly reduces the proportion of active materials, leading to a significant decrease in battery energy density, which contradicts the core R&D goal of high energy density in all-solid-state batteries. Second, when increasing the electrode areal density to improve battery energy density, the electrode thickness increases accordingly, significantly extending the transport distance of lithium ions within the electrode. Even with the addition of a solid electrolyte, it is difficult to construct an efficient long-range ion transport network, failing to fully utilize its ion conduction function, resulting in a significant decline in battery rate performance and cycle stability. This ion transport bottleneck is particularly pronounced under high areal density conditions, becoming a key pain point restricting the industrialization of silicon-based all-solid-state batteries.

[0005] Therefore, how to further improve the electrode surface density while reducing the amount of solid electrolyte used on the negative electrode side, and achieve a synergistic improvement in battery energy density, rate performance and cycle performance, has become a technical challenge that urgently needs to be overcome in the field of all-solid-state batteries.

[0006] In view of this, the present invention is hereby proposed. Summary of the Invention

[0007] The primary objective of this invention is to provide a negative electrode sheet that achieves efficient utilization of solid electrolyte through the design of a specific structure of the negative electrode sheet, thereby achieving higher energy density, higher rate capability, and longer cycle performance with a lower amount of solid electrolyte added to the negative electrode sheet.

[0008] The second objective of this invention is to provide a method for preparing a negative electrode sheet.

[0009] A third objective of this invention is to provide an all-solid-state battery.

[0010] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted: This invention provides a negative electrode sheet, comprising a negative electrode active material, a solid electrolyte, a conductive agent, and a binder; The solid electrolyte is distributed in a cylindrical form within the negative electrode sheet.

[0011] Furthermore, the negative electrode sheet includes a negative current collector and a negative electrode material layer disposed on the surface of the negative current collector; the negative electrode material layer is provided with a plurality of cylindrical pores penetrating the negative electrode material layer, and the solid electrolyte is filled in the cylindrical pores.

[0012] Furthermore, the mass of the solid electrolyte accounts for 5% to 30% of the total mass of the negative electrode active material, the solid electrolyte, the conductive agent, and the binder.

[0013] Furthermore, the negative electrode sheet satisfies the following relationship: 1.5≤D1 / D2≤5.0; where D1 is the pore diameter of the cylindrical pores in μm; and D2 is the average particle size of the solid electrolyte in μm.

[0014] Furthermore, 1.0μm≤D1≤10.0μm.

[0015] Furthermore, 0.3μm≤D2≤5.0μm.

[0016] Furthermore, the negative electrode active material includes at least one of silicon-carbon composite material, silicon-oxygen material, micron-sized silicon material, porous silicon material, nano-sized silicon material, and hollow silicon material; And / or, the solid electrolyte includes at least one of sulfide solid electrolyte, oxide solid electrolyte, halide solid electrolyte and polymer solid electrolyte.

[0017] Furthermore, the conductive agent includes at least one of conductive carbon black, carbon nanotubes, vapor-grown carbon fibers, graphene, and carbon quantum dots.

[0018] The present invention also provides a method for preparing the negative electrode sheet as described above, comprising the following steps: S1. Mix the negative electrode active material, conductive agent, binder and solvent to obtain slurry A; coat the slurry A onto the negative electrode current collector, and after drying and rolling, obtain the electrode substrate; S2. A cylindrical pore perpendicular to the negative electrode current collector is etched on the electrode substrate using laser etching. S3. Mix the solid electrolyte, binder and solvent to obtain slurry B; coat the slurry B onto the etched electrode substrate, and after drying, obtain the negative electrode.

[0019] The present invention also provides an all-solid-state battery, including the negative electrode sheet as described above.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: The negative electrode of this invention, through the design of a specific structure, constructs cylindrical pores that penetrate the negative electrode material layer, and the solid electrolyte is filled in the cylindrical pores, realizing the efficient utilization of the solid electrolyte; it forms a longitudinally penetrating ion-conducting network, improving ion transport and solid-solid interface of the thick electrode; thus achieving higher energy density, higher rate capability and longer cycle performance with a relatively low amount of solid electrolyte added to the negative electrode. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the structure of the all-solid-state battery of the present invention. Detailed Implementation

[0023] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and 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.

[0024] In some embodiments of the present invention, a negative electrode sheet is provided, comprising a negative electrode active material, a solid electrolyte, a conductive agent, and a binder; The solid electrolyte is distributed in a cylindrical form within the negative electrode sheet.

[0025] The negative electrode of this invention, through the design of a specific structure, forms a longitudinally penetrating ion-conducting network, improving ion transport and solid-solid interface of the thick electrode; it achieves efficient utilization of solid electrolyte; thus achieving higher energy density, higher rate capability and longer cycle performance with a lower amount of solid electrolyte added to the negative electrode.

[0026] In some embodiments of the present invention, the negative electrode sheet includes a negative electrode current collector and a negative electrode material layer disposed on the surface of the negative electrode current collector; The negative electrode material layer includes the negative electrode active material, solid electrolyte, conductive agent and binder; The negative electrode material layer has several cylindrical pores that penetrate the negative electrode material layer, and the solid electrolyte is filled in the cylindrical pores; that is, the cylindrical pores in the negative electrode sheet penetrate the negative electrode material layer, the cylindrical pores are perpendicular to the negative electrode current collector, and the cylindrical pores are evenly distributed in the negative electrode material layer.

[0027] In some embodiments of the present invention, the mass of the solid electrolyte accounts for 5% to 30% of the total mass of the negative electrode active material, solid electrolyte, conductive agent, and binder; typically, but not limitingly, for example, the mass of the solid electrolyte accounts for 5%, 7%, 9%, 10%, 13%, 15%, 17%, 20%, 22%, 25%, 27%, 30% of the total mass of the negative electrode active material, solid electrolyte, conductive agent, and binder, and a range between any two thereof. The ratio of the mass of the solid electrolyte to the total mass of the negative electrode active material, solid electrolyte, conductive agent, and binder is M, where 5% ≤ M ≤ 30%; preferably, 10% ≤ M ≤ 25%.

[0028] To further regulate the negative electrode structure and improve the utilization of solid electrolyte, this invention optimizes the ratio of the pore size of the cylindrical pores to the average particle size of the solid electrolyte, thereby enhancing the utilization rate of the solid electrolyte and achieving multi-dimensional optimization of energy density, rate performance, and cycle performance. In some embodiments of this invention, the negative electrode satisfies the following relationship: 1.5 ≤ D1 / D2 ≤ 5.0; where D1 is the pore size of the cylindrical pores in μm; and D2 is the average particle size of the solid electrolyte in μm. Typically, but not limitingly, the value of D1 / D2 can be 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, or any value between two of these.

[0029] In some embodiments of the present invention, 1.0 μm ≤ D1 ≤ 10.0 μm; typically, but not limitingly, D1 can be a range of 1.0 μm, 2.0 μm, 3.0 μm, 4.0 μm, 5.0 μm, 6.0 μm, 7.0 μm, 8.0 μm, 9.0 μm, 10.0 μm, and any two thereof; preferably, 2.5 μm ≤ D1 ≤ 7.5 μm; more preferably, 3 μm ≤ D1 ≤ 5 μm.

[0030] In some embodiments of the present invention, 0.3 μm ≤ D2 ≤ 5.0 μm; typically, but not limitingly, D2 can be a range of 0.3 μm, 0.5 μm, 1.0 μm, 1.5 μm, 2.0 μm, 2.5 μm, 3.0 μm, 3.5 μm, 4.0 μm, 4.5 μm, 5.0 μm, and any two thereof; preferably, 0.5 μm ≤ D2 ≤ 4.0 μm; more preferably, 1.0 μm ≤ D2 ≤ 2.0 μm.

[0031] This invention constructs micron-sized cylindrical pores that penetrate the negative electrode material layer inside the negative electrode sheet, and fills the cylindrical pores with solid electrolyte to form a longitudinally penetrating ion-conducting network, thereby improving ion transport and solid-solid interface of the thick electrode.

[0032] In some embodiments of the present invention, the height of the cylindrical pores is H, where 20 μm ≤ H ≤ 100 μm; the height of the cylindrical pores is the thickness of the negative electrode material layer; typically, but not limitingly, for example, the height of the cylindrical pores can be 20 μm, 40 μm, 60 μm, 80 μm, 100 μm, and any value between two of these.

[0033] In some embodiments of the present invention, the negative electrode active material includes at least one of silicon-carbon composite material, silicon-oxygen material, micron-sized silicon material, porous silicon material, nano-sized silicon material, and hollow silicon material; preferably, the micron-sized silicon material includes, but is not limited to, micron-sized silicon powder.

[0034] In some embodiments of the present invention, the solid electrolyte includes at least one of sulfide solid electrolyte, oxide solid electrolyte, halide solid electrolyte and polymer solid electrolyte; preferably, the sulfide solid electrolyte includes, but is not limited to, Li6PS5Cl.

[0035] In some embodiments of the present invention, the conductive agent includes at least one of conductive carbon black, carbon nanotubes, vapor-grown carbon fibers, graphene, and carbon quantum dots; preferably, the carbon nanotubes include, but are not limited to, single-walled carbon nanotubes (SWCNTs).

[0036] In some embodiments of the present invention, the adhesive includes, but is not limited to, polyacrylic acid (PAA) and / or polyvinylidene fluoride (PVDF).

[0037] In some embodiments of the present invention, a method for preparing the above-mentioned negative electrode sheet is also provided, comprising the following steps: S1. Mix the negative electrode active material, conductive agent, binder and solvent to obtain slurry A; coat slurry A onto the negative electrode current collector, and after drying and rolling, obtain the electrode substrate; S2. A cylindrical pore perpendicular to the negative electrode current collector is etched on the electrode substrate using laser etching. S3. Mix the solid electrolyte, binder and solvent to obtain slurry B; coat slurry B onto the etched electrode substrate, and after drying, obtain the negative electrode.

[0038] This invention uses laser etching to prepare a negative electrode sheet with a specific structure, thereby achieving efficient utilization of solid electrolyte.

[0039] In some embodiments of the present invention, in step S1, the mass ratio of the negative electrode active material, conductive agent, binder and solvent is 100:1.5~2.5:0.5~1.5:90~110; preferably, the solvent includes, but is not limited to, N-methylpyrrolidone (NMP).

[0040] In some embodiments of the present invention, in step S1, the negative electrode active material, conductive agent, binder and solvent are mixed to obtain slurry A; slurry A is coated on the negative electrode current collector, and after the solvent is dried, a negative electrode material layer is formed; after the negative electrode material layer is rolled, an electrode substrate is obtained; preferably, the drying temperature is 50~70℃, and the negative electrode material layer is rolled to a compaction density of 0.8~1.3g / cc.

[0041] In some embodiments of the present invention, in step S2, a cylindrical pore penetrating the negative electrode material layer and perpendicular to the negative electrode current collector is etched on the electrode substrate by laser etching.

[0042] In some embodiments of the present invention, in step S3, the mass ratio of the solid electrolyte, binder and solvent is 100:1.5~2.5:90~110; preferably, the solvent includes, but is not limited to, N-methylpyrrolidone (NMP).

[0043] In some embodiments of the present invention, in step S3, the solid electrolyte, binder and solvent are mixed to obtain slurry B; slurry B is coated on the negative electrode material layer in the etched electrode substrate, and after the solvent is dried, a negative electrode is obtained; preferably, the drying temperature is 50~70°C.

[0044] See Figure 1 In some embodiments of the present invention, an all-solid-state battery is also provided, including the above-mentioned negative electrode sheet; preferably, the all-solid-state battery includes a positive electrode material layer, an electrolyte membrane and a negative electrode material layer arranged sequentially.

[0045] The negative electrode sheet with a specific structure of the present invention realizes the efficient utilization of solid electrolyte, which significantly improves the energy density, rate performance and long cycle performance of all-solid-state batteries.

[0046] Examples 1-11 The negative electrode sheet provided in Examples 1-11 includes a negative electrode current collector and a negative electrode material layer disposed on the surface of the negative electrode current collector; the negative electrode material layer includes a negative electrode active material, a solid electrolyte, a conductive agent and a binder; The negative electrode material layer has several cylindrical pores that penetrate the negative electrode material layer and are perpendicular to the negative electrode current collector; the solid electrolyte is filled in the cylindrical pores; the ratio of the mass of the solid electrolyte to the total mass of the negative electrode active material, the solid electrolyte, the conductive agent and the binder is M; the pore size of the cylindrical pores is D1; ​​the average particle size of the solid electrolyte is D2; the height H of the cylindrical pores is 50 μm; M, D1, D2 and D1 / D2 of Examples 1 to 11 are shown in Table 1.

[0047] The method for preparing the negative electrode sheet provided in Examples 1-11 includes the following steps: S1. The negative electrode active material (micron-sized silicon powder), conductive agent (single-walled carbon nanotubes, SWCNT), binder (polyacrylic acid, PAA) and solvent (N-methylpyrrolidone, NMP) are mixed in a mass ratio of 100:2:1:100 to obtain slurry A; slurry A is coated on copper foil, and the solvent is dried at 60°C to form a negative electrode material layer; the negative electrode material layer is rolled to a compaction density of 1.0 g / cc to obtain the electrode substrate; S2. A cylindrical pore penetrating the negative electrode material layer and perpendicular to the negative electrode current collector is etched on the electrode substrate using laser etching; wherein, the diameter of the cylindrical pore is D1. S3. A solid electrolyte (Li6PS5Cl) with an average particle size of D2, a binder (polyvinylidene fluoride, PVDF), and a solvent (N-methylpyrrolidone, NMP) are mixed in a mass ratio of 100:2:100 to obtain slurry B. Slurry B is coated onto the negative electrode material layer in the etched electrode substrate. After drying the solvent at 60°C, the negative electrode is obtained.

[0048] Table 1

[0049] The preparation method of the all-solid-state battery provided in Examples 1-11 includes the following steps: The positive electrode active material (LiNi) 0.8 Co 0.1 Mn 0.1 O2, electrolyte (Li6PS5Cl), conductive agent (VGCF), binder (PVDF) and solvent (NMP) are mixed in a mass 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. The positive electrode, electrolyte membrane (Li6PS5Cl), and negative electrode (the negative electrode of Examples 1 to 11 above) are stacked and assembled into a 1Ah pouch cell. The cells are then formed by isostatic pressing and finally subjected to a pressure of 5MPa to obtain an all-solid-state battery.

[0050] Comparative Example 1 The negative electrode sheet provided in this comparative example includes a negative electrode current collector and a negative electrode material layer disposed on the surface of the negative electrode current collector; the negative electrode material layer includes a negative electrode active material, a solid electrolyte, a conductive agent and a binder; The negative electrode material layer has several cylindrical pores that penetrate the negative electrode material layer and are perpendicular to the negative electrode current collector; the solid electrolyte is filled in the cylindrical pores; the ratio of the mass of the solid electrolyte to the total mass of the negative electrode active material, solid electrolyte, conductive agent and binder is M; the pore size of the cylindrical pores is D1; ​​the average particle size of the solid electrolyte is D2; the height H of the cylindrical pores is 50 μm; M is 2%; D1 is 13.8 μm; D2 is 1.63 μm; and D1 / D2 is 8.47.

[0051] The method for preparing the negative electrode sheet provided in this comparative example includes the following steps: S1. The negative electrode active material (micron-sized silicon powder), conductive agent (single-walled carbon nanotubes, SWCNT), binder (polyacrylic acid, PAA) and solvent (N-methylpyrrolidone, NMP) are mixed in a mass ratio of 100:2:1:100 to obtain slurry A; slurry A is coated on copper foil, and the solvent is dried at 60°C to form a negative electrode material layer; the negative electrode material layer is rolled to a compaction density of 1.0 g / cc to obtain the electrode substrate; S2. A cylindrical pore penetrating the negative electrode material layer and perpendicular to the negative electrode current collector is etched on the electrode substrate using laser etching; wherein, the diameter of the cylindrical pore is D1. S3. A solid electrolyte (Li6PS5Cl) with an average particle size of D2, a binder (polyvinylidene fluoride, PVDF), and a solvent (N-methylpyrrolidone, NMP) are mixed in a mass ratio of 100:2:100 to obtain slurry B. Slurry B is coated onto the negative electrode material layer in the etched electrode substrate. After drying the solvent at 60°C, the negative electrode is obtained.

[0052] The preparation method of the all-solid-state battery provided in this comparative example is based on Example 1.

[0053] Comparative Example 2 The negative electrode sheet provided in this comparative example includes a negative electrode current collector and a negative electrode material layer (without cylindrical pores) disposed on the surface of the negative electrode current collector; the negative electrode material layer includes a negative electrode active material, a solid electrolyte, a conductive agent and a binder; the thickness of the negative electrode material layer is 50 μm; the ratio of the mass of the solid electrolyte to the total mass of the negative electrode active material, the solid electrolyte, the conductive agent and the binder is M, and M is 10%.

[0054] The method for preparing the negative electrode sheet provided in this comparative example includes the following steps: The negative electrode active material (micron-sized silicon powder), conductive agent (single-walled carbon nanotubes, SWCNT), binder (polyacrylic acid, PAA), solid electrolyte (Li6PS5Cl), and solvent (N-methylpyrrolidone, NMP) are mixed in a mass ratio of 100:2:1:11.4:100 to obtain a slurry. The slurry is coated onto a copper foil, and the solvent is dried at 60°C to form a negative electrode material layer. The negative electrode material layer is rolled to a compaction density of 1.0 g / cc to obtain a negative electrode sheet.

[0055] The preparation method of the all-solid-state battery provided in this comparative example is based on Example 1.

[0056] Comparative Example 3 The method for preparing the negative electrode sheet provided in this comparative example includes the following steps: The negative electrode active material (micron-sized silicon powder), conductive agent (single-walled carbon nanotubes, SWCNT), binder (polyacrylic acid, PAA), and solvent (N-methylpyrrolidone, NMP) are mixed in a mass ratio of 100:2:1:100 to obtain a slurry. The slurry is coated onto a copper foil, and after the solvent is dried at 60°C, a negative electrode material layer with a thickness of 50 μm is formed. The negative electrode material layer is rolled to a compaction density of 1.0 g / cc to obtain the negative electrode sheet.

[0057] The preparation method of the all-solid-state battery provided in this comparative example is based on Example 1.

[0058] Test case The performance of the all-solid-state batteries of Examples 1-11 and Comparative Examples 1-3 was tested, and the results are shown in Table 2.

[0059] Energy density: The energy density is obtained by charging to 4.2V at 0.1C, resting for 10 minutes, discharging to 2.5V at 0.1C, and dividing the discharge energy by the mass of the all-solid-state battery.

[0060] 3C rate retention rate: Charge at 0.33C constant current to 4.2V, then switch to 4.2V constant voltage charging to 0.05C, rest for 10 minutes, and discharge at 0.1C to 2.5V; Charge at 0.33C constant current to 4.2V, then switch to 4.2V constant voltage charging to 0.05C, rest for 10 minutes, and discharge at 3C to 2.5V. Record the ratio of 3C discharge capacity to 0.1C discharge capacity as the 3C rate retention rate.

[0061] 0.5C cycle retention: Charge at 0.5C constant current to 4.2V, then switch to 4.2V constant voltage charging to 0.05C, rest for 10 minutes, and discharge at 0.5C to 2.5V. 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.

[0062] Table 2

[0063] As can be seen from Table 2, the negative electrode sheet with the specific structure of the present invention achieves efficient utilization of solid electrolyte and significantly improves the energy density, rate performance and long cycle performance of all-solid-state batteries.

[0064] Although the present invention has been illustrated and described with specific embodiments, it should be understood that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; those skilled in the art should understand that modifications can 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, without departing from the spirit and scope of the present invention; and these 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; therefore, this means that all such substitutions and modifications that fall within the scope of the present invention are included in the appended claims.

Claims

1. A negative electrode sheet, characterized in that, It includes negative electrode active material, solid electrolyte, conductive agent and binder; The solid electrolyte is distributed in a cylindrical form within the negative electrode sheet.

2. The negative electrode sheet according to claim 1, characterized in that, The negative electrode sheet includes a negative current collector and a negative electrode material layer disposed on the surface of the negative current collector; the negative electrode material layer is provided with a plurality of cylindrical pores penetrating the negative electrode material layer, and the solid electrolyte is filled in the cylindrical pores.

3. The negative electrode sheet according to claim 1, characterized in that, The solid electrolyte accounts for 5% to 30% of the total mass of the negative electrode active material, the solid electrolyte, the conductive agent, and the binder.

4. The negative electrode sheet according to claim 2, characterized in that, The negative electrode sheet satisfies the following relationship: 1.5≤D1 / D2≤5.0; where D1 is the pore diameter of the cylindrical pores in μm; and D2 is the average particle size of the solid electrolyte in μm.

5. The negative electrode sheet according to claim 4, characterized in that, 1.0μm≤D1≤10.0μm.

6. The negative electrode sheet according to claim 4, characterized in that, 0.3μm≤D2≤5.0μm.

7. The negative electrode sheet according to claim 4, characterized in that, The negative electrode active material includes at least one of silicon-carbon composite material, silicon-oxygen material, micron-sized silicon material, porous silicon material, nano-sized silicon material, and hollow silicon material; And / or, the solid electrolyte includes at least one of sulfide solid electrolyte, oxide solid electrolyte, halide solid electrolyte and polymer solid electrolyte.

8. The negative electrode sheet according to claim 4, characterized in that, The conductive agent includes at least one of conductive carbon black, carbon nanotubes, vapor-grown carbon fibers, graphene, and carbon quantum dots.

9. The method for preparing the negative electrode sheet according to any one of claims 1 to 8, characterized in that, Includes the following steps: S1. Mix the negative electrode active material, conductive agent, binder and solvent to obtain slurry A; coat the slurry A onto the negative electrode current collector, and after drying and rolling, obtain the electrode substrate; S2. A cylindrical pore perpendicular to the negative electrode current collector is etched on the electrode substrate using laser etching. S3. Mix the solid electrolyte, binder and solvent to obtain slurry B; coat the slurry B onto the etched electrode substrate, and after drying, obtain the negative electrode.

10. An all-solid-state battery, characterized in that, Includes the negative electrode sheet as described in any one of claims 1 to 8.

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