All-solid-state battery and three-dimensional interface construction method of all-solid-state battery and application thereof

Abstract

The application discloses a three-dimensional interface construction method of a full solid-state battery and a full solid-state battery, and belongs to the technical fields of electrode preparation, electrolyte preparation and full solid-state battery. The method adopts a silk screen printing process, first coats a first layer of electrode or electrolyte coating and preforms a net structure on the surface, then coats another layer of electrode coating or electrolyte coating with a net structure on the surface of the preformed net coating, so that a three-dimensional interface structure is formed between the adjacent coatings; the above operation is repeated, and a three-dimensional interface structure can also be constructed between the electrode and the electrolyte. A multilayer gradient electrode can also be prepared by designing different coating components of the electrode. The application can significantly improve the bonding strength between the layers of the full solid-state battery, increase the effective contact area of the interface, expand the carrier transmission path, improve the carrier transmission performance of the interface, and meanwhile, a variety of functional expansion can be realized, so that the application requirement of different energy storage devices can be met.

Description

Technical Field

[0001] This invention relates to the field of solid-state battery fabrication technology, and more specifically, to an all-solid-state battery, a method for constructing a three-dimensional interface for an all-solid-state battery, and its application. Background Technology

[0002] Currently, the electrode layer interface and electrode / electrolyte interface in solid-state batteries are mainly planar structures. These planar contact interfaces suffer from small bonding area, insufficient bonding strength, poor mechanical properties, and insufficient electron and ion transport capabilities, which limit the electrochemical performance of all-solid-state batteries. Although a few studies have attempted to construct three-dimensional interface structures using methods such as irregular roll forming and 3D printing, these methods are often limited by performance, cost, and efficiency, making it difficult to meet the needs of practical applications.

[0003] To address the aforementioned issues, researchers have developed several conventional solid-state battery fabrication methods and three-dimensional interface structure electrode / cell construction methods, mainly including the following categories: 1. Preparation of flat-panel interfacial solid-state batteries by coating method Patents CN110931849B, CN202511983405.6, CN116779766A, and CN102468476A disclose methods for preparing planar electrodes or electrolyte layers through planar coating or powder pressing, followed by assembly with the electrolyte to form a solid-state battery. In batteries obtained using these methods, both the electrode layers and the electrode / electrolyte interface are planar. Because the interlayer interface is a simple planar contact with a small bonding area and no physical interlocking structure, delamination easily occurs when the electrode volume changes (such as the expansion of silicon-based materials), resulting in low bonding strength and limiting the battery's cycle stability.

[0004] 2. Aerosol spraying / electrostatic spraying method Patents CN119400802A and CN105098227A disclose schemes for constructing multi-layer gradient electrodes layer by layer through spraying. While this method is relatively simple to operate, the interlayer bonding relies solely on physical stacking, lacking a stable three-dimensional interface structure, resulting in low bonding strength, poor electrode edge quality, and a high susceptibility to delamination failure during battery charging and discharging. Furthermore, the spraying process struggles to achieve a fine three-dimensional structure on the electrode surface and cannot actively control the electrode's microstructure.

[0005] 3. 3D printing method Some studies have employed 3D printing technology to fabricate batteries or electrodes with three-dimensional interfaces, such as CN110571475A and CN119133617B. While these methods theoretically allow for high-precision structural customization, they face significant bottlenecks in practical applications: ① Extremely low processing efficiency; printing is time-consuming and typically requires separate printing of the positive and negative electrodes before battery assembly. ② Poor system compatibility; the printing process necessitates the addition of ionic and electronic insulating molding agents to meet rheological requirements, which is detrimental to electrochemical performance. Furthermore, the heating, melting, or photocuring of the molding agent inevitably leads to adverse chemical reactions with solid electrolytes such as sulfides and halide oxides, significantly negatively impacting performance. ③ High cost, making it difficult to meet the demands of large-scale, low-cost production.

[0006] 4. Irregular shape rolling method Patents such as CN116565121A and CN121439714A attempt to form grooves on the electrode surface by combining layer-by-layer coating with roll forming grooving before filling with polymer electrolyte. While this method can improve interlayer bonding to some extent, the roll forming process causes localized stress concentration and uneven density on the electrode, leading to a decrease in mechanical stability and carrier transport capacity. Furthermore, it is difficult to construct a fine three-dimensional interface, and is generally only applicable to polymer solid-state battery systems, making it difficult to apply to inorganic all-solid-state battery systems such as sulfide, oxide, and halide batteries.

[0007] 5. Preparation of gradient electrolytes by screen printing Existing patents, such as CN110931849B, disclose a method for preparing gradient solid electrolyte layers using screen printing. This method improves the interfacial compatibility between the electrolyte and the positive / negative electrodes by controlling the concentration gradient distribution of polymers, lithium salts, and fast-ion conductors. However, this technology only involves the material concentration gradient of the electrolyte layer and does not address the structural design of the electrode layers, let alone mention constructing a three-dimensional interface between the electrode layers. Its product form is a planar multilayer electrolyte membrane with simple planar contact between the layers, lacking the three-dimensional interface structure described in this application.

[0008] 6. Three-dimensional solid-state battery US2018090791 (A1) discloses a solid-state battery with both "vertical" and "parallel" orientations. The technical feature of this patent lies in the three-dimensional geometry of the battery itself, where both the electrode layer and electrolyte layer incorporate both vertical and parallel orientations, but the interface is essentially still a planar contact (a plane has both vertical and parallel orientations). Furthermore, this patent has the following limitations: ① The interface is a right-angled planar contact (see its specification and figures for a description of the vertical and parallel geometric relationship), leading to stress concentration and a tendency for localized cracks during battery cycling; ② A smooth transition between the electrodes and electrolyte is not achieved through a curved interlocking structure, and the interface contact area is not substantially increased; ③ Periodic gaps exist in the battery structure, resulting in lower energy density for the same volume; ④ The fabrication method does not employ screen printing technology, making it difficult to achieve high-precision, high-efficiency, large-scale fabrication.

[0009] Based on the above analysis, existing all-solid-state battery interface fabrication technologies generally suffer from the following common problems: Low interlayer bonding strength: Whether it is pressing or coating, the interlayer interface is a simple planar contact with a small bonding area and no three-dimensional interface structure, making it easy to delaminate when the electrode volume changes.

[0010] The contradiction between efficiency and cost is prominent: high-precision methods (such as 3D printing) are extremely inefficient, have poor system compatibility, and are expensive; low-cost methods (such as coating and roll forming) cannot meet the requirements of fine three-dimensional structures.

[0011] It is difficult to achieve both interlayer bonding strength and electrochemical performance: existing methods either sacrifice interlayer bonding strength (such as coating method) or sacrifice electrochemical activity (such as adding a large amount of inactive molding agent in 3D printing), making it difficult to obtain high bonding strength and excellent charge carrier transport performance at the same time.

[0012] Unreasonable interface geometry: Some three-dimensional structures (such as US2018090791A1) use right-angled plane contacts, which poses a risk of stress concentration and local cracks, and the periodic void structure reduces the volumetric energy density.

[0013] Therefore, how to provide a three-dimensional interface construction method that can simultaneously achieve high layer bonding strength, optimize interface stress distribution, and increase interface contact area in all-solid-state batteries, while also having the advantages of high production efficiency and low cost, has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0014] This invention aims to address the technical pain points of existing all-solid-state battery fabrication methods, such as poor interlayer bonding strength, difficulties in carrier transport, poor system compatibility, high production costs, low efficiency, and inability to meet the technical requirements of solid-state batteries. It provides a method for fabricating a three-dimensional interface structure solid-state battery based on screen printing. This invention utilizes the high precision and efficiency advantages of screen printing. By adjusting the slurry viscosity or screen design (e.g., adjusting the screen mesh count, wire diameter, and slurry viscosity), a three-dimensional mesh texture interface structure is formed on the electrode / electrolyte interface or the internal interface of multiple electrode layers through printing mesh interlocking. This structural design optimizes the electron and ion transport paths within the electrode, alleviates stress concentration during the electrode reaction process, and reduces interfacial polarization, thereby significantly improving the rate performance and cycle stability of energy storage devices (especially high-energy-density all-solid-state batteries). It greatly enhances interlayer bonding strength, improves carrier transport capability, and simultaneously enables various functional expansions to adapt to the needs of different energy storage devices.

[0015] The first aspect of this invention provides a method for constructing a three-dimensional interface for an all-solid-state battery, comprising the following steps: (1) Prepare electrode paste and / or electrolyte paste suitable for screen printing. Optionally, the electrode slurry includes positive electrode slurry and negative electrode slurry. The electrode slurry includes active materials, electrolyte, binder, and solvent, and may also include conductive agents, such as conductive carbon, which can be selectively added according to the actual application requirements. Electrolyte slurry typically contains solid electrolyte and binder.

[0016] Optionally, the active material can be any one or more of the following: ternary lithium cathode material, lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium iron phosphate, sulfur and sulfides, lithium titanate, layered sodium cathode material, Prussian blue, sodium vanadium phosphate, sodium vanadium fluorophosphate, sodium iron phosphate, sodium manganese iron phosphate, sodium iron pyrophosphate, sodium vanadium fluorophosphate, silicon, graphite, hard carbon, silicon suboxide, or lithium silicon alloy.

[0017] Optionally, the electrolyte material can be selected from one or more of oxides, halides, halide oxides, sulfides, and polymers. For example, the electrolyte material can be La. 2 / 3-x Li x TiO3, Li 1.3 Al 0.3 Ti 1.7 (PO4)3, Li7La3Zr2O 12 Li 10 GeP2S 12 Li3PS4, Li7PS 11 , Li6PS5Cl, LiBF4, LiBH4, Li2ZrCl6, LiNbOCl4, LiTaOCl4, Li3Al3O2C l8Any one or more of TaCl5-0.5Li2O, NaNbOCl4, or NaTaOCl4.

[0018] The conductive agent can be one or more of the following conductive additives: Super P, conductive carbon black, acetylene black, Ketjen black, multi-walled carbon nanotubes, single-walled carbon nanotubes, fumed carbon fiber (VGCF), graphite, or graphene.

[0019] The adhesive can be one or more of the following: polyvinylidene fluoride (PVDF), polyvinylidene fluoride-hexafluoropropylene, styrene-butadiene rubber, sodium carboxymethyl cellulose, polyacrylic acid, sodium alginate, xanthan gum, polyvinyl alcohol, polytetrafluoroethylene, nitrile rubber (NBR), thermoplastic polyurethane, or polyethylene oxide.

[0020] The solvent can be one or more of the following solvents compatible with solid-state battery systems: toluene, xylene, trimethylbenzene, anisole, n-pentane, n-hexane, n-heptane, cyclohexane, methylcyclohexane, petroleum ether, butyl acetate, butyl butyrate, 1,6-dichlorohexane, chlorobenzene, o-dichlorobenzene, dichloromethane, anhydrous ethanol, tetrahydrofuran (THF), diethyl ether, or propyl ether.

[0021] To ensure smooth ink flow and prevent leakage during screen printing, the viscosity of the ink paste needs to be adjusted to a suitable range. Optionally, the viscosity of both the electrode paste and the electrolyte paste is 6000-600000 mPa·s. For example, the viscosity of the electrode paste can be 6000 mPa·s, 10000 mPa·s, 15000 mPa·s, 20000 mPa·s, 25000 mPa·s, 30000 mPa·s, 35000 mPa·s, 40000 mPa·s, 45000 mPa·s, 50000 mPa·s, 55000 mPa·s, 60000 mPa·s, 65000 mPa·s, 70000 mPa·s, 75000 mPa·s, 80000 mPa·s, 85000 mPa·s, 90000 mPa·s, 95000 mPa·s, or 100000 mPa·s. , 105000mPa·s, 110000mPa·s, 115000mPa·s, 120000mPa·s, 125000mPa·s, 130000mPa·s, 135000mPa·s, 140000mPa·s, 145000mPa·s, 150000m Pa·s, 155000mPa·s, 160000mPa·s, 165000mPa·s, 170000mPa·s, 175000mPa·s, 180000mPa·s, 185000mPa·s, 190000mPa·s, 195000mPa·s, 200 000mPa·s, 205000mPa·s, 210000mPa·s, 215000mPa·s, 220000mPa·s, 225000mPa·s, 230000mPa·s, 235000mPa·s, 240000mPa·s, 245000mPa·s , 250000mPa·s, 255000mPa·s, 260000mPa·s, 265000mPa·s, 270000mPa·s, 275000mPa·s, 280000mPa·s, 285000mPa·s, 290000mPa·s, 295000m Pa·s, 300000mPa·s, 305000mPa·s, 310000mPa·s, 315000mPa·s, 320000mPa·s, 325000mPa·s, 330000mPa·s, 335000mPa·s, 340000mPa·s, 345 000mPa·s, 350000mPa·s, 355000mPa·s, 360000mPa·s, 365000mPa·s, 370000mPa·s, 375000mPa·s, 380000mPa·s, 385000mPa·s, 390000mPa·s,395000mPa·s, 400000mPa·s, 405000mPa·s, 410000mPa·s, 415000mPa·s, 42000 0mPa·s, 425000mPa·s, 430000mPa·s, 435000mPa·s, 440000mPa·s, 445000mPa· s, 450000mPa·s, 455000mPa·s, 460000mPa·s, 465000mPa·s, 470000mPa·s, 475 000mPa·s, 480000mPa·s, 485000mPa·s, 490000mPa·s, 495000mPa·s, 500000mP Any point value or a range between any two points from a·s, 505000mPa·s, 510000mPa·s, 515000mPa·s, 520000mPa·s, 525000mPa·s, 530000mPa·s, 535000mPa·s, 540000mPa·s, 545000mPa·s, 550000mPa·s, 555000mPa·s, 560000mPa·s, 565000mPa·s, 570000mPa·s, 575000mPa·s, 580000mPa·s, 585000mPa·s, 590000mPa·s, 595000mPa·s, or 600000mPa·s.

[0022] For the slurry of the three-dimensional interface multilayer gradient electrode, in addition to the general requirements mentioned above, the positive electrode slurry or negative electrode slurry also needs to be configured with at least two sets of electrode slurries. Each set of electrode slurries should differ in at least one of the following: type of active material, content of active material, porosity, and type of electrolyte material, in order to form a functional gradient.

[0023] Optionally, the active material type gradient refers to using different active materials in different layers, such as using lithium silicon alloy in the inner layer, silicon suboxide in the middle layer, and micron-sized silicon in the outer layer, to alleviate volume expansion.

[0024] Optionally, when the functional gradient is a gradient layer of active material component content, the difference in active material content between adjacent layers is 5%-40%. For example, the active material content increases or decreases from the inner layer to the outer layer. For example, the difference in active material content between adjacent layers can be any point value or a range between any two points from 5%, 10%, 15%, 20%, 25%, 30%, 35%, or 40%.

[0025] Optionally, when the functional gradient is a porosity gradient layer, the porosity gradient can be achieved by adding a pore-forming agent to the slurry, with the pore-forming agent content accounting for 5%-20% of the total slurry mass. The pore-forming agent can be selected from any one or more of polyvinyl alcohol (PVA), polystyrene (PS), polymethyl methacrylate (PMMA), starch, naphthalene, ammonium carbonate, ammonium bicarbonate, or polyethylene glycol (PEG). For example, the pore-forming agent content as a percentage of the total slurry mass can be any point value or a range between any two points from 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, or 20%.

[0026] (2) Design and prepare printing screens based on the preset three-dimensional mesh texture interface structure; The three-dimensional mesh texture interface structure is formed as follows: using the mesh texture of a printing screen, a mesh-like recessed texture is formed on the printed surface. For example, the surface of the three-dimensional mesh texture interface structure can be wavy, with alternating peaks and troughs in its cross-section. The spacing between adjacent peaks or troughs is 50-500 μm, and the height difference (also referring to the depth) between the peaks and troughs is 1-100 μm.

[0027] This application allows for the adjustment of mesh depth and spacing by modifying parameters such as wire diameter, mesh angle, mesh count, and paste viscosity. Simultaneously, it enables the fabrication of specialized printing screens for printing insulating borders and electrolyte layers, ensuring that the printing precision of the insulating borders and electrolyte layers matches that of the electrode layers.

[0028] (3) Using the printing screen prepared in step (2), the paste prepared in step (1) is printed onto the substrate through screen printing process to form at least one electrode layer and at least one electrolyte layer. After each electrode layer or electrolyte layer is printed, it is dried and shaped to make the surface present a three-dimensional mesh texture interface structure, so that the interfaces of adjacent layers are combined with each other through the three-dimensional mesh texture interface structure to form a three-dimensional mesh texture interface structure with a mesh depth of 1-100μm. Then, it is assembled to obtain an all-solid-state battery.

[0029] Optionally, in step (3), the printing is to sequentially print the positive electrode slurry, electrolyte slurry and negative electrode slurry onto the substrate to form at least one positive electrode layer, at least one electrolyte layer and at least one negative electrode layer, and a three-dimensional mesh texture interface structure is formed between adjacent positive electrode layers, adjacent negative electrode layers and adjacent electrode / electrolyte layer interfaces. Optionally, in step (3), the printing is to sequentially print the negative electrode slurry, electrolyte slurry and positive electrode slurry onto the substrate to form at least one negative electrode layer, at least one electrolyte layer and at least one positive electrode layer, and a three-dimensional mesh texture interface structure is formed between adjacent negative electrode layers, adjacent positive electrode layers and adjacent electrode / electrolyte layer interfaces. Optionally, in step (3), the printing is to sequentially print the positive electrode slurry and the electrolyte slurry onto the substrate to form at least one positive electrode layer and at least one electrolyte layer, and a three-dimensional mesh texture interface structure is formed between adjacent positive electrode layers and between adjacent positive electrode layer / electrolyte layer interfaces. Optionally, in step (3), the printing involves sequentially printing the negative electrode slurry and the electrolyte slurry onto the substrate to form at least one negative electrode layer and at least one electrolyte layer, with a three-dimensional mesh texture interface structure formed between adjacent negative electrode layers and between the interfaces of adjacent negative electrode layers / electrolyte layers.

[0030] Furthermore, it should be noted that in step (3) of this invention, it is not required that the positive electrode layer, electrolyte layer, and negative electrode layer are all prepared by screen printing. Those skilled in the art can choose according to actual needs: (a) The positive electrode slurry, electrolyte slurry and negative electrode slurry are all printed sequentially by screen printing, so that the positive electrode / electrolyte interface and the electrolyte / negative electrode interface both form a three-dimensional mesh texture interface structure; (b) Only the positive electrode slurry and electrolyte slurry are printed sequentially by screen printing, and the negative electrode can be bonded with commercially available metal foil, so that the positive electrode / electrolyte interface forms a three-dimensional grid texture interface structure. (c) Only the negative electrode slurry and electrolyte slurry are printed sequentially by screen printing, and the positive electrode uses commercially available or pre-prepared positive electrode sheets, so that the negative electrode / electrolyte interface forms a three-dimensional mesh texture interface structure.

[0031] Optionally, the texture depth of the three-dimensional mesh interface structure can be controlled from 1 to 100 μm. For example, the texture depth of the three-dimensional interface structure can be any point value or a range between any two points from 2 μm, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm, 60 μm, 65 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm, or 100 μm.

[0032] Optionally, the three-dimensional mesh texture interface structure is a three-dimensional bonding structure formed by the mesh texture, which creates physical interlocking between adjacent sub-layers in both the direction perpendicular to the layer interface and the direction parallel to the layer interface.

[0033] Optionally, the electrode layer is a multilayer electrode layer with functional gradients, and there is a three-dimensional mesh texture interface structure between adjacent sublayers; further, the multilayer electrode layer with functional gradients is a layer with active material component content gradient or a porosity gradient layer.

[0034] Optionally, when the functional gradient is an active material component content gradient layer, the content difference of active materials in adjacent layers is 5%-40%; when the functional gradient is a porosity gradient layer, it is achieved by adding a pore-forming agent to the slurry, and the content of the pore-forming agent accounts for 5%-20% of the total mass of the slurry.

[0035] Optionally, the screen printing process parameters are: printing pressure 0.02-5MPa, printing speed 10-5000mm / s, and printing angle 10°-80°.

[0036] For example, the printing pressure can be any point value or a range between any two points from 0.02MPa, 0.05MPa, 0.1MPa, 0.15MPa, 0.2MPa, 0.25MPa, 0.3MPa, 0.35MPa, 0.4MPa, 0.45MPa, 0.5MPa, 0.55MPa, 0.6MPa, 0.65MPa, 0.7MPa, 0.75MPa, 0.8MPa, 0.85MPa, 0.9MPa, 0.95MPa, 1.0MPa, 1.5MPa, 2MPa, 2.5MPa, 3MPa, 3.5MPa, 4MPa, 4.5MPa, or 5MPa.

[0037] For example, the printing speed can be any point value or a range between any two points from 10mm / s, 100mm / s, 500mm / s, 1000mm / s, 1500mm / s, 2000mm / s, 2500mm / s, 3000mm / s, 3500mm / s, 4000mm / s, 4500mm / s, or 5000mm / s.

[0038] For example, the printing angle can be any point value or a range between any two points from 10°, 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75° or 80°.

[0039] Optionally, the printing screen has a mesh count of 80-400, a wire diameter of 10-150μm, and a photosensitive emulsion thickness of 0-200μm; the printing accuracy deviation of the screen pattern is ≤3μm.

[0040] For example, the mesh count of a printing screen can be any point value or a range between any two points from 80 mesh, 100 mesh, 120 mesh, 140 mesh, 160 mesh, 180 mesh, 200 mesh, 220 mesh, 240 mesh, 260 mesh, 280 mesh, 300 mesh, 320 mesh, 340 mesh, 360 mesh, 380 mesh, or 400 mesh.

[0041] For example, the wire diameter of a printing screen can be any point value or a range between any two points from 10μm, 20μm, 30μm, 40μm, 50μm, 60μm, 70μm, 80μm, 90μm, 100μm, 110μm, 120μm, 130μm, 140μm or 150μm.

[0042] For example, the thickness of the photosensitive emulsion can be any point value or a range between any two points from 0μm, 5μm, 10μm, 15μm, 20μm, 25μm, 30μm, 35μm, 40μm, 45μm, 50μm, 55μm, 60μm, 65μm, 70μm, 75μm, 80μm, 85μm, 90μm, 95μm, 100μm, 105μm, 110μm, 115μm, 120μm, 125μm, 130μm, 135μm, 140μm, 145μm, 150μm, 155μm, 160μm, 165μm, 170μm, 175μm, 180μm, 185μm, 190μm, 195μm, or 200μm.

[0043] The electrode layer and electrolyte layer of this application can be a single layer or a multilayer structure obtained by multiple screen printing processes. The multilayer structure contains at least two sublayers, and the thickness or composition of each sublayer can be uniform or vary in a gradient. Optionally, the thickness of the electrode sublayer or electrolyte sublayer printed in a single pass can be 1-100 μm. For example, the thickness of the electrode or electrolyte layer printed in a single pass can be any value or a range between any two points from 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, or 100 μm.

[0044] Optionally, the thickness of a single layer of the multilayer gradient electrode is 1-100 μm, and the total thickness is 20-1000 μm. For example, the thickness of a single layer of the gradient electrode can be any value or a range between any two points from 20 μm, 40 μm, 60 μm, 80 μm, or 100 μm. The total thickness of the gradient electrode can be any value or a range between any two points from 20 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, or 1000 μm. Different layers of the multilayer gradient electrode should possess at least one functional gradient. Optionally, there may be differences in at least one of the following: type of active material, content of active material, porosity, and type of electrolyte material, to form a functional gradient.

[0045] Optionally, the conductive substrate can be one or more of a metal substrate, a carbon-based substrate, or a conductive ceramic substrate.

[0046] Optionally, step (3) may be repeated on the other side of the conductive substrate to prepare a battery with a three-dimensional mesh texture interface structure on both sides. Furthermore, during the printing of the double-sided electrodes, the alignment deviation of the mesh texture and gradient structure of the corresponding layers on both sides is ≤5μm.

[0047] Optionally, a spiral-shaped insulating border may be printed on the outermost layer of the electrode. For example, the width of the insulating border may be 0.1-20 mm, and the thickness may be 1-100 μm. For instance, the width of the insulating border can be any value or a range between any two points from 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm, or 2.0 mm. The thickness of the insulating border can be any value or a range between any two points from 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, or 100 μm.

[0048] A second aspect of this invention provides an all-solid-state battery, comprising a positive electrode layer, an electrolyte layer, and a negative electrode layer. The positive electrode layer, electrolyte layer, and negative electrode layer are all formed by screen printing, and the positive electrode layer and the electrolyte layer, as well as the electrolyte layer and the negative electrode layer, are bonded to each other through a three-dimensional mesh texture interface structure. The mesh depth of the three-dimensional mesh texture interface structure is 1-100 μm. Further, the mesh depth of the three-dimensional mesh texture interface structure does not exceed 80% of the sublayer thickness.

[0049] A third aspect of the present invention provides an all-solid-state battery, comprising a positive electrode layer, an electrolyte layer, and a negative electrode layer; the positive electrode layer and the electrolyte layer are bonded together by a three-dimensional mesh texture interface structure, which is formed at the interface by screen printing.

[0050] For example, the surface of the three-dimensional mesh texture interface structure is wavy, and its cross-section has alternating peaks and valleys. The height difference (depth) between the peaks and valleys is 1-100μm, and the spacing between adjacent peaks or valleys is 50-500μm.

[0051] For example, at least one of the positive electrode layer and the negative electrode layer is a multilayer structure, and adjacent sublayers are also connected to each other through a three-dimensional mesh texture interface structure. For example, both the positive electrode layer and the negative electrode layer include 2-10 sublayers.

[0052] Compared with the prior art, the present invention achieves at least one of the following beneficial effects: 1. This invention innovatively applies screen printing technology to the construction of three-dimensional interfaces for all-solid-state batteries, which has the advantages of high precision, high efficiency, and customizable fine structures. It can realize the construction of all-solid-state batteries with three-dimensional interfaces, solving the problems of poor interlayer bonding, poor rate performance, low efficiency, and high cost of existing planar solid-state batteries, as well as the pain points of cumbersome three-dimensional interface construction process and insufficient precision. It significantly improves the production efficiency of solid-state batteries, reduces production costs, and facilitates large-scale industrial production.

[0053] 2. This invention constructs a three-dimensional interface in an all-solid-state battery through screen printing. Combined with multi-layer screen printing, it enables the interfaces of adjacent electrode / electrolyte layers and the interfaces within multiple electrode layers to interlock, forming a three-dimensional mesh-textured interface structure. This significantly improves the interlayer bonding strength, reaching over 16 N / cm after isostatic pressing. This effectively prevents interlayer cracking caused by volume changes during battery charging and discharging, while also improving the carrier transport capacity of electrons and ions and reducing interface polarization. Furthermore, it solves the problems of low carrier transport efficiency and poor mechanical stability in traditional gradient electrodes, significantly improving the mechanical stability and fast-charging performance of all-solid-state batteries.

[0054] 3. The three-dimensional mesh texture interface structure formed by screen printing technology in this invention allows for curved surface contact between adjacent electrode layers and adjacent electrode / electrolyte layers, avoiding stress concentration at right angles, reducing the risk of local cracks, and improving mechanical stability. Furthermore, the larger contact area is beneficial for carrier transport.

[0055] 4. This invention covers the construction of various three-dimensional interface gradient electrodes, including component content gradient, porosity gradient, and multi-material type gradient (including active materials, electrolyte materials, etc.), which can further improve carrier transport and can be adapted to various energy storage devices such as solid-state batteries, liquid batteries, and fuel cells. It has a wide range of applications and is compatible with different types of electrolyte materials, further expanding the application scenarios of electrodes.

[0056] 5. This invention features a simple process, requiring no special customized equipment or stringent reaction conditions. Screen printing enables continuous production, and the three-dimensional interface parameters can be flexibly adjusted. Electrodes with different structures can be customized according to actual needs, making it highly practical. Furthermore, compared to existing methods for constructing three-dimensional interfaces (such as 3D printing), this method is more efficient, lower in cost, and more suitable for large-scale production. In addition, this invention can also utilize screen printing to achieve multiple functions such as insulating border printing and double-sided electrode fabrication. Attached Figure Description

[0057] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings: Figure 1A schematic diagram of a solid-state battery structure with a three-dimensional interface is shown. Figure 2 A schematic diagram of the structure of an all-solid-state battery with multilayer gradient electrodes is shown. Figure 3 A schematic diagram of a typical flat-panel solid-state battery structure is shown. Figure 4 A physical diagram of the three-dimensional interface structure (electrode interface) of Embodiment 1 of the present invention is shown; Figure 5 An SEM image of the surface texture of the electrode in Example 1 is shown; Figure 6 The following graph shows a comparison of the rate performance of Examples 1 and 2 and Comparative Examples 1 and 3.

[0058] Figure 1 In the middle: 1-positive electrode; 2-electrolyte layer; 3-negative electrode; 4-positive electrode current collector; 5-negative electrode current collector.

[0059] Figure 2 In the middle: 1-positive electrode; 2-electrolyte layer; 3-outer layer of negative electrode; 4-inner layer of negative electrode; 5-positive electrode current collector; 6-negative electrode current collector.

[0060] Figure 3 In the middle: 1-plate positive electrode; 2-electrolyte layer; 3-plate negative electrode; 4-positive electrode current collector; 5-negative electrode current collector. Detailed Implementation

[0061] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0062] Unless otherwise specified, the raw materials used in the embodiments and comparative examples of this application were all purchased commercially.

[0063] Unless otherwise specified, the methods used in the embodiments and comparative examples of this application are conventional methods in the prior art.

[0064] Example 1: All-solid-state battery with a three-dimensional mesh texture interface structure This embodiment prepares an all-solid-state battery with a three-dimensional textured interface. The positive electrode material is a ternary positive electrode material (NCM811), the electrolyte layer is Li6PS5Cl, and the negative electrode is a silicon negative electrode. The specific steps are as follows: (1) Substrate selection: Carbon-coated aluminum foil was selected as the conductive substrate for screen printing.

[0065] (2) Slurry preparation: Prepare positive electrode slurry, electrolyte slurry and negative electrode slurry for all-solid-state batteries. Adjust the slurry viscosity to about 80,000 mPa·s by changing the amount of toluene solvent added. The formulation of each slurry component is as follows: Positive electrode slurry: NCM811:LiNbOCl4:VGCF:NBR = 80:17:1:2 (mass ratio); Electrolyte slurry: Li6PS5Cl: NBR = 97.5: 1.5 (mass ratio) Negative electrode slurry: Si: Li6PS5Cl: Super P: NBR = 85:12:1:2 (mass ratio).

[0066] (3) Screen printing stencil design and preparation: Three sets of screen printing stencils were prepared for printing the positive electrode layer, electrolyte layer and negative electrode layer, respectively. The mesh counts were 120, 200 and 200 mesh, the wire diameters were 60, 50 and 50 μm, and the photosensitive emulsion thicknesses were 10 μm, 100 μm and 120 μm from the inner layer to the outer layer.

[0067] (4) Multilayer screen printing: The carbon-coated aluminum foil is fixed on the screen printing equipment, and the positive electrode paste, electrolyte paste, and negative electrode paste are printed in sequence. After each layer is printed, it is pre-dried at 80°C for 5 minutes. After printing the negative electrode, it is combined with the foamed copper current collector and then pre-dried. The printing parameters for each layer are as follows: printing pressure 0.3MPa, printing speed 100mm / s, and printing angle 45°.

[0068] (5) Battery assembly: The printed composite is placed in a drying oven and dried at 80°C for 60 minutes to remove the remaining solvent. Then, the tabs are welded and the composite is packaged to form an all-solid-state pouch battery with a three-dimensional interlayer textured interface. Before testing, the all-solid-state pouch battery is subjected to isostatic pressure treatment with a pressure of 200 MPa.

[0069] refer to Figure 1 As shown, Figure 1 A schematic diagram of a solid-state battery with a three-dimensional mesh texture interface structure is shown. The solid-state battery with a three-dimensional mesh texture interface structure includes, in sequence, a positive electrode current collector 4, a positive electrode layer 1, an electrolyte layer 2, a negative electrode layer 3, and a negative electrode current collector.

[0070] refer to Figure 4 As shown, Figure 4 A physical diagram of the three-dimensional interface structure (electrode interface) of Embodiment 1 of the present invention is shown.

[0071] refer to Figure 5 As shown, Figure 5 An SEM image of the surface texture of the electrode in Example 1 is shown.

[0072] The all-solid-state battery prepared in this embodiment has a total cathode thickness of approximately 100 μm, an electrolyte layer thickness of approximately 40 μm, and a negative electrode thickness of approximately 40 μm. The mesh patterns at adjacent layer interfaces interlock to form a three-dimensional interface structure. The mesh spacing at the cathode / electrolyte interface is approximately 150 μm, with a precision deviation of less than 5 μm and a maximum mesh depth of approximately 20 μm. The mesh spacing at the electrolyte / negative electrode interface is approximately 80 μm, with a precision deviation of less than 3 μm and a maximum mesh depth of approximately 15 μm. The interlayer bonding strength of the all-solid-state battery is no less than 18.6 N / cm. The fast-charging performance of the all-solid-state battery is significantly improved compared to traditional solid-state batteries, achieving a discharge capacity of approximately 124 mAh / g at a 5C high rate, and retaining 85% of its capacity after 50 cycles.

[0073] Example 2: Three-dimensional interface all-solid-state battery with multi-layered gradient negative electrode In the three-dimensional interface all-solid-state battery prepared in this embodiment, the negative electrode has a material gradient (multilayer negative electrode of active material: micron-sized silicon / silicon suboxide; electrolyte layer is Li6PS5Cl, positive electrode material is lithium cobalt oxide, and substrate is copper foil). The specific steps are as follows: (1) Substrate selection: 8μm thick copper foil was selected as the negative electrode printed conductive substrate, and 10μm aluminum foil was selected as the positive electrode printed conductive substrate.

[0074] (2) Slurry preparation: Prepare two sets of negative electrode slurry, one set of electrolyte slurry and one set of positive electrode slurry. Adjust the viscosity of the electrode slurry to about 60,000 mPa·s and the viscosity of the electrolyte slurry to about 40,000 mPa·s to ensure no printing leakage and smooth ink flow. The electrode slurries for all-solid-state batteries all contain active materials, electrolytes, conductive carbon, binders and tetrahydrofuran solvent. The electrolyte slurry consists of tetrahydrofuran solvent, binder and Li6PS5Cl electrolyte, and the formula is as follows: Negative electrode slurry 1 (inner layer): Micron-sized silicon: Li6PS5Cl: Ketjen Black: SBR = 70:25:2:3 (mass ratio); Negative electrode slurry 2 (middle layer): silicon suboxide: Li6PS5Cl: Ketjen Black: SBR = 70:25:2:3 (mass ratio); Li6PS5Cl electrolyte slurry: Li6PS5Cl:SBR = 97.5:1.5 (mass ratio).

[0075] (3) Screen printing screen design and preparation: Design two sets of negative electrode, one set of electrolyte and one set of positive electrode printing screens. The negative electrode screen has a mesh number of 250 mesh and a wire diameter of 40 μm. The photosensitive emulsion thickness is 10 and 40 μm respectively. The positive electrode and electrolyte screens have mesh numbers of 120 and 200 mesh and wire diameters of 70 and 40 μm respectively. The photosensitive emulsion thickness is 10 and 100 μm from the inner layer to the outer layer respectively.

[0076] (4) Multilayer screen printing: Under a nitrogen atmosphere, negative electrode paste 1, negative electrode paste 2 and electrolyte paste are printed sequentially on copper foil. After each layer is printed, it is pre-dried at 70°C for 5 minutes. Finally, the positive electrode is printed and laminated with aluminum foil, and then pre-dried again. Printing parameters for each layer: printing pressure 0.4MPa, printing speed 200mm / s, printing angle 50°.

[0077] (5) Drying and assembly: Dry at 80°C for 30 minutes under nitrogen atmosphere, then weld the tabs and encapsulate, and perform isostatic pressing.

[0078] refer to Figure 2 As shown, Figure 2 A schematic diagram of a solid-state battery with multi-layer gradient electrodes is shown. The solid-state battery with a three-dimensional mesh texture interface structure of multi-layer gradient negative electrodes includes, in sequence, a positive electrode current collector 5, a positive electrode layer 1, an electrolyte layer 2, an outer negative electrode layer 3, an inner negative electrode layer 4, and a negative electrode current collector 6.

[0079] In the all-solid-state battery prepared in this embodiment, the total thickness of the negative electrode is approximately 60 μm, the inner layer thickness is approximately 30 μm, the outer layer thickness is approximately 30 μm, the electrolyte layer thickness is approximately 40 μm, and the positive electrode thickness is approximately 120 μm. Adjacent layers interlock to form a three-dimensional mesh structure. The maximum mesh depth at the inner interface of the negative electrode and the negative electrode / electrolyte interface is approximately 10 μm with a spacing of 60 μm, while the maximum mesh depth at the positive electrode / electrolyte interface is approximately 25 μm with a spacing of 80 μm. The interlayer bonding strength is not less than 17.2 N / cm, the discharge capacity at 5C rate is approximately 149 mAh / g, and the capacity retention rate is 91% after 50 cycles, effectively alleviating the volume expansion of silicon-based materials and the problem of lithium plating during fast charging.

[0080] Example 3: Three-dimensional interface all-solid-state battery with multi-layered gradient cathode This embodiment fabricates a three-dimensional interface all-solid-state battery with a multi-layered gradient cathode. The cathode active material is NCM811, the electrolyte layer is Li6PS5Cl, and the anode is lithium metal. The multi-layered gradient cathode has a dual gradient in component content and electrolyte type. The content of the ternary material (NCM811) increases from the inside out, and the electrolyte content decreases from the inside out. The electrolytes in each cathode layer are Li2ZrCl6, LiNbOCl4, and Li6PS5Cl, respectively. The specific steps are as follows: (1) Substrate selection: Carbon-coated aluminum foil was selected as the conductive substrate for screen printing (positive current collector).

[0081] (2) Slurry preparation: Three sets of positive electrode slurries and one set of electrolyte slurries were prepared. The viscosity of each set of positive electrode slurries was adjusted to about 70,000 mPa·s by adding tetrahydrofuran solvent, and the viscosity of the electrolyte slurry was adjusted to about 30,000 mPa·s. The formulations of each slurry are as follows: Positive electrode slurry 1 (inner layer): NCM811: Li2ZrCl6:Super P:PVDF = 75:22:1:2 (mass ratio); Cathode slurry 2 (middle layer): NCM811: LiNbOCl4: Super P:PVDF = 80:17:1:2 (mass ratio) Positive electrode slurry 3 (outer layer): NCM811: Li6PS5Cl: Super P:PVDF = 85:12:1:2 (mass ratio).

[0082] Electrolyte slurry: Li6PS5Cl: NBR = 97.5:1.5 (mass ratio) (3) Screen printing stencil design and preparation: Three sets of positive electrode printing stencils and one set of electrolyte printing stencils were prepared. The positive electrode stencils were all 150 mesh with a wire diameter of 60 μm, and the corresponding diameters from the inner layer to the outer layer were 10 μm, 50 μm, and 100 μm. The electrolyte stencils were 200 mesh with a wire diameter of 60 μm and a photosensitive emulsion thickness of 150 μm.

[0083] (4) Multi-layer screen printing: The carbon-coated aluminum foil is fixed on the screen printing equipment, and the positive electrode paste 1, 2, 3 and electrolyte paste are printed in sequence. After each layer is printed, it is pre-dried at 80°C for 5 minutes. The printing parameters for each layer are: printing pressure 0.3MPa, printing speed 100mm / s, and printing angle 45°.

[0084] (5) Drying and assembly: The printed positive electrode + electrolyte composite is placed in a drying oven and dried at 80°C for 60 min. Then it is bonded to a 20 μm thick lithium foil and combined with a copper foil current collector. After welding the positive and negative electrode tabs, aluminum-plastic film encapsulation and flat plate pressurization are performed at a pressure of about 10 MPa.

[0085] The all-solid-state battery with a three-dimensional textured interface prepared in this embodiment has a total positive electrode thickness of approximately 150 μm, a single-layer thickness of approximately 45-55 μm, an electrolyte layer thickness of approximately 40 μm, and a negative electrode of 20 μm lithium foil. Within the multi-layered positive electrode, the textures of adjacent layers at the positive electrode / electrolyte interface interlock to form a three-dimensional interface structure. The texture spacing is approximately 100 μm, with a precision deviation of less than 3 μm, and a maximum texture depth of approximately 25 μm. Except for the lithium metal negative electrode, the interlayer bonding strength is not less than 18.1 N / cm. The texture depth at the negative electrode / electrolyte interface is relatively shallow (3-5 μm) to accommodate the lithium foil negative electrode. This all-solid-state battery can operate under a low stacking pressure of 5 MPa, with a 5C discharge capacity of approximately 112 mAh / g and a capacity retention of 75% after 50 cycles.

[0086] Example 4: All-solid-state battery with a three-dimensional mesh texture interface structure This comparative example uses screen printing to prepare a solid-state battery with a three-dimensional interface. Compared with Example 1, the three-dimensional textured interface has a shallower interlocking depth, with a maximum of about 1 μm. The specific steps are as follows: This embodiment prepares an all-solid-state battery with a three-dimensional textured interface. The positive electrode material is a ternary positive electrode material (NCM811), the electrolyte layer is Li6PS5Cl, and the negative electrode is a silicon negative electrode. The specific steps are as follows: (1) Substrate selection: consistent with Example 1.

[0087] (2) Slurry preparation: The composition is the same as in Example 1, and the viscosity of the positive electrode, negative electrode and electrolyte slurry is adjusted to 40000 mPa·s.

[0088] (3) Screen printing stencil design and preparation: Three sets of screen printing stencils were prepared for printing the positive electrode layer, electrolyte layer and negative electrode layer respectively. The mesh counts were 120, 200 and 200 mesh respectively, the wire diameters were 20, 20 and 50 μm respectively, and the photosensitive emulsion thicknesses from the inner layer to the outer layer were 50 μm, 120 μm and 150 μm respectively.

[0089] (4) Multilayer screen printing: The carbon-coated aluminum foil is fixed on the screen printing equipment, and the positive electrode paste, electrolyte paste, and negative electrode paste are printed in sequence. After each layer is printed, it is pre-dried at 80°C for 5 minutes. After printing the negative electrode, it is combined with the foamed copper current collector and then pre-dried. The printing parameters for each layer are as follows: printing pressure 0.3MPa, printing speed 100mm / s, and printing angle 45°.

[0090] (5) Battery assembly: The printed composite is placed in a drying oven and dried at 80°C for 60 minutes to remove the remaining solvent. Then, the tabs are welded and the composite is packaged to form an all-solid-state pouch battery with a three-dimensional interlayer textured interface. Before testing, the all-solid-state pouch battery is subjected to isostatic pressure treatment with a pressure of 200 MPa.

[0091] The all-solid-state battery prepared in this embodiment has a total positive electrode thickness of approximately 90 μm, an electrolyte layer thickness of approximately 35 μm, and a negative electrode thickness of approximately 30 μm. The mesh patterns at adjacent layer interfaces interlock to form a three-dimensional interface structure. The mesh spacing at the positive electrode / electrolyte interface is approximately 150 μm, with a precision deviation of less than 5 μm and a maximum mesh depth of approximately 1 μm. The mesh spacing at the electrolyte / negative electrode interface is approximately 80 μm, with a precision deviation of less than 5 μm and a maximum mesh depth of approximately 1 μm. The interlayer bonding strength of the all-solid-state battery is no less than 16 N / cm. The fast-charging performance of the all-solid-state battery is improved compared to traditional solid-state batteries, achieving a discharge capacity of approximately 106 mAh / g at a 5C high rate, and retaining 74% of its capacity after 50 cycles.

[0092] Example 5: All-solid-state battery with a three-dimensional mesh texture interface structure This comparative example uses screen printing to prepare a solid-state battery with a three-dimensional interface. Compared with Example 1, the three-dimensional textured interface has a deeper interlocking depth, with a maximum of approximately 100 μm. The specific steps are as follows: This embodiment prepares an all-solid-state battery with a three-dimensional textured interface. The positive electrode material is a ternary positive electrode material (NCM811), the electrolyte layer is Li6PS5Cl, and the negative electrode is a silicon negative electrode. The specific steps are as follows: (1) Substrate selection: consistent with Example 1.

[0093] (2) Slurry preparation: The composition is the same as in Example 1, and the slurry viscosity is adjusted to 100,000 mPa·s.

[0094] (3) Screen printing stencil design and preparation: Three sets of screen printing stencils were prepared for printing the positive electrode layer, electrolyte layer and negative electrode layer respectively. The mesh counts were 80, 100 and 100 mesh respectively, the wire diameters were 120, 100 and 100 μm respectively, and the photosensitive emulsion thicknesses from the inner layer to the outer layer were 10 μm, 120 μm and 200 μm respectively.

[0095] (4) Multilayer screen printing: The carbon-coated aluminum foil is fixed on the screen printing equipment, and the positive electrode paste, electrolyte paste, and negative electrode paste are printed in sequence. After each layer is printed, it is pre-dried at 80°C for 5 minutes. After printing the negative electrode, it is combined with the foamed copper current collector and then pre-dried. The printing parameters for each layer are as follows: printing pressure 0.3MPa, printing speed 100mm / s, and printing angle 45°.

[0096] (5) Battery assembly: The printed composite is placed in a drying oven and dried at 80°C for 60 minutes to remove the remaining solvent. Then, the tabs are welded and the composite is packaged to form an all-solid-state pouch battery with a three-dimensional interlayer textured interface. Before testing, the all-solid-state pouch battery is subjected to isostatic pressure treatment with a pressure of 200 MPa.

[0097] In this embodiment, the thicknesses of the positive electrode, electrolyte, and negative electrode are approximately 150, 100, and 100 μm, respectively. The mesh patterns of adjacent layers interlock to form a three-dimensional interface structure. The electrolyte thickness is approximately 150 μm, the mesh pattern spacing at the positive electrode / electrolyte interface is less than 10 μm, and the maximum mesh pattern depth is approximately 100 μm. The mesh pattern spacing at the electrolyte / negative electrode interface is approximately 150 μm, the accuracy deviation is less than 10 μm, and the maximum mesh pattern depth is approximately 70 μm. This embodiment has a higher mesh pattern depth than Example 1 and higher interlayer strength, not less than 19.4 N / cm. However, due to the higher electrode thickness and higher active material loading, the rate performance is weaker than Example 1, with a 5C discharge capacity of approximately 116 mAh / g and a capacity retention of 78% after 50 cycles.

[0098] Comparative Example 1: Preparation of Flat Panel Solid-State Batteries by Coating Method This comparative example uses a layer-by-layer coating process to prepare a flat-panel interface solid-state battery. Compared with Example 1, it does not use screen printing and therefore does not form a three-dimensional mesh texture interface structure. The specific steps are as follows: (1) Substrate selection: Aluminum foil and copper foil were selected as positive and negative conductive substrates, respectively, consistent with the current collector in Example 1. The electrolyte was coated on the PET base film.

[0099] (2) Slurry preparation: Prepare three sets of slurries with the same formula as in Example 1. Adjust the viscosity of the slurry to 7000 mPa·s, which is suitable for flat plate coating.

[0100] (3) Layer-by-layer coating: The positive electrode, electrolyte and negative electrode are coated separately using a flat plate coating method. After each layer is coated, it is dried, which is the same as in Example 1, at 80°C for 60 min.

[0101] (4) Assembly: The positive electrode, electrolyte membrane (removing the PET base film) and negative electrode are stacked and assembled. After welding the tabs, they are encapsulated in aluminum-plastic and then subjected to isostatic pressing at 200 MPa.

[0102] refer to Figure 3 As shown, Figure 3 A schematic diagram of a typical flat-plate solid-state battery structure is shown. A typical flat-plate solid-state battery sequentially includes a positive current collector 4, a flat positive electrode 1, an electrolyte layer 2, a flat negative electrode 3, and a negative current collector.

[0103] In this comparative example, the total thickness of the positive electrode of the all-solid-state battery is approximately 100 μm, the electrolyte layer is approximately 40 μm thick, and the negative electrode is approximately 40 μm thick. The adjacent electrolyte layers are only simply planar bonded, without forming an interlocking structure. After isostatic pressing, the interlayer bonding strength is only 10.6 N / cm, and delamination is prone to occur between layers, making it difficult to meet the required carrier transport capacity. The discharge capacity at 5C is approximately 92 mAh / g, and the capacity retention is only 60% after 50 cycles.

[0104] Comparative Example 2: 3D Printing for the Fabrication of Solid-State Batteries with Three-Dimensional Interfaces This comparative example uses 3D printing to fabricate a solid-state battery with a three-dimensional interface. Compared with Example 1, its fabrication efficiency is low, and the curing agent used in 3D printing is difficult to be compatible with the sulfide electrolyte. The specific steps are as follows: (1) Substrate selection: A 10μm thick aluminum foil was selected as the conductive substrate, which is the same as the substrate in Example 1.

[0105] (2) Ink composition: It contains no solvent, but adds 5% curing agent. The rest of the formula is completely consistent with the slurry corresponding to Example 1.

[0106] (3) 3D printing: The positive electrode, electrolyte and negative electrode are printed layer by layer. The three-dimensional interface parameters are controlled in the same way as in Example 1. The solidification is carried out while printing. The pressing time for a single layer is about 120 minutes.

[0107] (4) Assembly: After welding the tabs, aluminum-plastic encapsulation is performed, followed by isostatic pressing at 200 MPa.

[0108] The electrode prepared in this comparative example has a total positive electrode thickness of approximately 100 μm. The interlayer texture parameters are controlled in the same way as in Example 1, and the interlayer bonding strength is not less than 17.7 N / cm. Printing production efficiency is far lower than screen printing (single-layer printing takes approximately 2-3 seconds). Although it offers higher precision and strength in interface structure, the electrode composition uniformity is very poor, and the solidified components hinder carrier transport, resulting in excessive impedance. Therefore, it is impossible to test charge-discharge performance and cannot meet actual needs.

[0109] Comparative Example 3: Preparation of solid-state batteries with three-dimensional interfaces by coating + irregular roll pressing method This comparative example uses a layer-by-layer coating + irregular roll pressing method to prepare a solid-state battery with a three-dimensional interface. Compared with Example 1, the intercalation depth is approximately 20 μm. The specific steps are as follows: (1) Substrate selection: consistent with Example 1.

[0110] (2) Slurry preparation: Prepare three sets of slurries with the same formula as in Example 1. Adjust the viscosity of the slurry to 7000 mPa·s, which is suitable for flat plate coating.

[0111] (3) Layer-by-layer coating + irregular roll pressing: The positive electrode, electrolyte and negative electrode are coated in sequence using a flat plate coating method. After each coating is dried, the positive electrode and electrolyte are coated and dried. Then, the next layer is coated on the surface using a roll with a raised mesh pattern. The thickness is the same as in Example 1.

[0112] (4) Assembly: After welding the positive electrode, electrolyte and negative electrode composite with tabs, it is encapsulated in aluminum-plastic, and then subjected to isostatic pressing at 200 MPa.

[0113] In this comparative example, the spacing between the positive electrode and electrolyte interfacial ripples is approximately 150 μm, with a precision deviation of less than 10 μm and a maximum ripple depth of approximately 20 μm. The spacing between the electrolyte and negative electrode interfacial ripples is approximately 80 μm, with a precision deviation of less than 5 μm and a maximum ripple depth of approximately 0.5 μm. After isostatic pressing, the interlayer bonding strength of the all-solid-state battery is no less than 11.7 N / cm, the discharge capacity at a 5C high rate is approximately 98 mAh / g, and the capacity retention rate is 66% after 50 cycles. Compared to the planar all-solid-state battery in Comparative Example 1, this comparative example shows a slight improvement in interlayer strength and electrochemical performance. However, due to the weak three-dimensional interfacial bonding and the uneven density caused by irregular rolling, it differs significantly from Example 1.

[0114] Comparative Example 4: All-solid-state battery with a three-dimensional mesh texture interface structure This comparative example uses screen printing to prepare a solid-state battery with a three-dimensional interface. The embedding depth of the battery with the three-dimensional textured interface is relatively shallow, with a maximum of approximately 0.5 μm. The specific steps are as follows: This embodiment prepares an all-solid-state battery with a three-dimensional textured interface. The positive electrode material is a ternary positive electrode material (NCM811), the electrolyte layer is Li6PS5Cl, and the negative electrode is a silicon negative electrode. The specific steps are as follows: (1) Substrate selection: consistent with Example 1.

[0115] (2) Slurry preparation: The composition is the same as in Example 1, and the viscosity of the positive electrode, negative electrode and electrolyte slurry is adjusted to 45000 mPa·s.

[0116] (3) Screen printing stencil design and preparation: Three sets of screen printing stencils were prepared for printing the positive electrode layer, electrolyte layer and negative electrode layer respectively. The mesh counts were 120, 200 and 200 mesh respectively, the wire diameters were 10, 10 and 40 μm respectively, and the photosensitive emulsion thicknesses from the inner layer to the outer layer were 50 μm, 120 μm and 150 μm respectively.

[0117] (4) Multilayer screen printing: The carbon-coated aluminum foil is fixed on the screen printing equipment, and the positive electrode paste, electrolyte paste, and negative electrode paste are printed in sequence. After each layer is printed, it is pre-dried at 80°C for 5 minutes. After printing the negative electrode, it is combined with the foamed copper current collector and then pre-dried. The printing parameters for each layer are as follows: printing pressure 0.3MPa, printing speed 100mm / s, and printing angle 45°.

[0118] (5) Battery assembly: The printed composite is placed in a drying oven and dried at 80°C for 60 minutes to remove the remaining solvent. Then, the tabs are welded and the composite is packaged to form an all-solid-state pouch battery with a three-dimensional interlayer textured interface. Before testing, the all-solid-state pouch battery is subjected to isostatic pressure treatment with a pressure of 200 MPa.

[0119] The all-solid-state battery prepared in this embodiment has a total cathode thickness of approximately 90 μm, an electrolyte layer thickness of approximately 35 μm, and a negative electrode thickness of approximately 30 μm. The mesh patterns at adjacent layer interfaces interlock to form a three-dimensional interface structure. The mesh spacing at the cathode / electrolyte interface is approximately 150 μm, with a precision deviation of less than 5 μm and a maximum mesh depth of approximately 0.5 μm. The mesh spacing at the electrolyte / negative electrode interface is approximately 80 μm, with a precision deviation of less than 5 μm and a maximum mesh depth of approximately 0.5 μm. Due to the shallow mesh, after isostatic pressing, it is not significantly different from a planar solid-state battery. The all-solid-state battery has an interlayer bonding strength of 12.5 N / cm, a discharge capacity of approximately 97 mAh / g at a high rate of 5C, and a capacity retention of 65% after 50 cycles.

[0120] Comparative Example 5: All-solid-state battery with a three-dimensional mesh texture interface structure This comparative example uses screen printing to prepare a solid-state battery with a three-dimensional interface. Compared with Example 1, the three-dimensional textured interface has a deeper interlocking depth, with a maximum of approximately 120 μm. The specific steps are as follows: This embodiment prepares an all-solid-state battery with a three-dimensional textured interface. The positive electrode material is a ternary positive electrode material (NCM811), the electrolyte layer is Li6PS5Cl, and the negative electrode is a silicon negative electrode. The specific steps are as follows: (1) Substrate selection: consistent with Example 1.

[0121] (2) Slurry preparation: The composition is the same as in Example 1, and the slurry viscosity is adjusted to 120000 mPa·s.

[0122] (3) Screen printing stencil design and preparation: Three sets of screen printing stencils were prepared for printing the positive electrode layer, electrolyte layer and negative electrode layer, respectively. The mesh counts were 80, 90 and 90 mesh, the wire diameters were 150, 130 and 130 μm, respectively, and the photosensitive emulsion thicknesses from the inner layer to the outer layer were 50 μm, 150 μm and 200 μm, respectively.

[0123] (4) Multilayer screen printing: The carbon-coated aluminum foil is fixed on the screen printing equipment, and the positive electrode paste, electrolyte paste, and negative electrode paste are printed in sequence. After each layer is printed, it is pre-dried at 80°C for 5 minutes. After printing the negative electrode, it is combined with the foamed copper current collector and then pre-dried. The printing parameters for each layer are as follows: printing pressure 0.3MPa, printing speed 100mm / s, and printing angle 45°.

[0124] (5) Battery assembly: The printed composite is placed in a drying oven and dried at 80°C for 60 minutes to remove the remaining solvent. Then, the tabs are welded and the composite is packaged to form an all-solid-state pouch battery with a three-dimensional interlayer textured interface. Before testing, the all-solid-state pouch battery is subjected to isostatic pressure treatment with a pressure of 200 MPa.

[0125] In this embodiment, the thicknesses of the positive electrode, electrolyte, and negative electrode are approximately 150, 100, and 100 μm, respectively. The mesh patterns of adjacent layers interlock to form a three-dimensional interface structure. The electrolyte thickness is approximately 150 μm, the mesh pattern spacing at the positive electrode / electrolyte interface has a precision deviation of less than 10 μm, and the maximum mesh pattern depth is approximately 130 μm. The mesh pattern spacing at the electrolyte / negative electrode interface is approximately 150 μm, the precision deviation is less than 10 μm, and the maximum mesh pattern depth is approximately 120 μm. In this embodiment, due to the excessively high mesh pattern depth, which exceeds 80% of the positive electrode thickness, through-cracks appear under isostatic pressing, and the interlayer strength is severely reduced to only 9 N / cm, making it difficult to test electrochemical performance.

[0126] Test case The solid-state batteries formed in the above embodiments and comparative examples were subjected to performance tests, as shown in Table 1.

[0127] Table 1

[0128] Referring to Table 1, this invention constructs a three-dimensional mesh-textured interface structure in an all-solid-state battery via screen printing. Compared to a planar interface (Example 1 vs. Comparative Example 1) under the same material configuration, this results in an interlayer bonding strength of no less than 18.6 N / cm, a 35% increase in 5C rate discharge capacity, and a more than 40% increase in 50-cycle capacity retention. Examples 1 and 3 demonstrate that the three-dimensional mesh-textured interface constructed by screen printing exhibits strong bonding and better stress state, which is more conducive to improving interlayer strength and electrochemical performance. A comparison of Example 2 and Example 1 shows that the gradient electrode prepared by screen printing can further improve rate and cycle performance. In summary, the experimental results indicate that this invention effectively solves the technical problems of low interlayer bonding strength, poor interfacial carrier transport efficiency, and insufficient cycle stability in existing planar battery structures, achieving a synergistic improvement in interlayer bonding strength and electrochemical performance. Figure 6 As shown, Figure 6 A comparison graph of the rate performance of Examples 1, 2 and Comparative Example 1 is shown. It can be seen that the 5C discharge capacity of Example 1 is increased by more than 30% compared with Comparative Example 1.

Claims

1. A method for constructing a three-dimensional interface for an all-solid-state battery, characterized in that, Includes the following steps: (1) Prepare electrode paste and / or electrolyte paste suitable for screen printing; (2) Design and prepare printing screens based on the preset three-dimensional mesh texture interface structure; (3) Using the printing screen prepared in step (2), the paste prepared in step (1) is printed onto the substrate through screen printing process to form at least one electrode layer and at least one electrolyte layer. After each electrode layer or electrolyte layer is printed, it is dried and shaped to make the surface present a three-dimensional mesh texture interface structure, so that the interfaces of adjacent layers are combined with each other through the three-dimensional mesh texture interface structure to form a three-dimensional mesh texture interface structure with a mesh depth of 1-100μm, thus obtaining an all-solid-state battery.

2. The method according to claim 1, characterized in that, In step (3), the printing is to sequentially print the positive electrode paste, electrolyte paste and negative electrode paste onto the substrate to form at least one positive electrode layer, at least one electrolyte layer and at least one negative electrode layer, and a three-dimensional mesh texture interface structure is formed between adjacent positive electrode layers, adjacent negative electrode layers and adjacent electrode / electrolyte layer interfaces. Alternatively, in step (3), the printing is to sequentially print the negative electrode slurry, electrolyte slurry and positive electrode slurry onto the substrate to form at least one negative electrode layer, at least one electrolyte layer and at least one positive electrode layer, and a three-dimensional mesh texture interface structure is formed between adjacent negative electrode layers, adjacent positive electrode layers and adjacent electrode / electrolyte layer interfaces. Alternatively, in step (3), the printing is to sequentially print the positive electrode slurry and the electrolyte slurry onto the substrate to form at least one positive electrode layer and at least one electrolyte layer, and to form a three-dimensional mesh texture interface structure between adjacent positive electrode layers and between adjacent positive electrode layer / electrolyte layer interfaces. Alternatively, in step (3), the printing is to sequentially print the negative electrode slurry and the electrolyte slurry onto the substrate to form at least one negative electrode layer and at least one electrolyte layer, with a three-dimensional mesh texture interface structure formed between adjacent negative electrode layers and between the interfaces of adjacent negative electrode layers / electrolyte layers.

3. The method according to claim 1, characterized in that, The electrode layer is a multilayer electrode layer with functional gradients, and there is a three-dimensional mesh texture interface structure between adjacent sublayers; furthermore, the multilayer electrode layer with functional gradients is a layer with a gradient content of active material components or a layer with a gradient porosity.

4. The method according to claim 3, characterized in that, When the functional gradient is an active material component content gradient layer, the content difference of active materials in adjacent layers is 5%-40%; when the functional gradient is a porosity gradient layer, it is achieved by adding a pore-forming agent to the slurry, and the content of the pore-forming agent accounts for 5%-20% of the total mass of the slurry.

5. The method according to claim 1, characterized in that, The viscosity of both the electrode slurry and the electrolyte slurry is 6000-600000 mPa·s.

6. The method according to claim 1, characterized in that, The screen printing process parameters are: printing pressure 0.02-5MPa, printing speed 10-5000mm / s, and printing angle 10°-80°. And / or the printing screen has a mesh count of 80-400, a wire diameter of 10-150μm, and a photosensitive emulsion thickness of 0-200μm; the printing accuracy deviation of the screen pattern is ≤3μm.

7. The method according to claim 1, characterized in that, The process also includes repeating step (3) on the other side of the substrate to prepare a battery with a three-dimensional mesh texture interface structure on both sides.

8. An all-solid-state battery, characterized in that, The all-solid-state battery includes a positive electrode layer, an electrolyte layer, and a negative electrode layer. The positive electrode layer, electrolyte layer, and negative electrode layer are formed by screen printing. The positive electrode layer and the electrolyte layer, as well as the electrolyte layer and the negative electrode layer, are bonded to each other through a three-dimensional mesh texture interface structure. The mesh depth of the three-dimensional mesh texture interface structure is 1-100μm.

9. The all-solid-state battery according to claim 8, characterized in that, The surface of the three-dimensional mesh texture interface structure has alternating peaks and troughs, with a height difference of 1-100 μm between the peaks and troughs, and a spacing of 50-500 μm between adjacent peaks or troughs.

10. The all-solid-state battery according to claim 8, characterized in that, At least one of the positive electrode layer and the negative electrode layer is a multi-layer structure, and adjacent sub-layers are also connected to each other through a three-dimensional mesh texture interface structure.

Images