Current collector adaptive to solid electrolyte, preparation method and application of current collector, and solid-state battery

Abstract

The invention relates to a current collector adaptive to a solid electrolyte, a preparation method and application of the current collector, and a solid-state battery, and relates to the field of solid-state batteries, the surface of the current collector is provided with a plurality of uniformly distributed bulges and pits; wherein the average particle size d of the solid electrolyte, the pit depth H, the pit opening size D and the bulge height h meet the following relation: the relational expression 1: H is 1.2 d-2. 0d and the like. Compared with the prior art, the method has the advantages that the parameters of the pits and the bulges on the surface of the current collector are accurately designed according to the particle size parameters of the solid electrolyte on the basis of a key matching concept, so that the solid electrolyte is embedded into the pits to form key type mechanical occlusion, and the problem of a solid-solid interface is fundamentally solved in the structural design level of the size adaptive design; and the interface micropores are thoroughly eliminated, so that the contact area of the electrolyte and the current collector is increased by 3-5 times, the interface bonding force and the ion transmission efficiency are further improved from the source, and a brand new technical path is provided for solving the solid-solid interface problem of the solid-state battery.

Description

A current collector adapted to solid-state electrolytes, its preparation method and application, and solid-state batteries. Technical Field

[0001] This invention relates to the field of solid-state batteries, and more particularly to a current collector adapted to solid-state electrolytes, its preparation method and application, and solid-state batteries. Background Technology

[0002] Solid-state batteries, as a core direction of next-generation new energy storage technology, have broad application prospects in electric vehicles, portable electronic devices, and large-scale energy storage due to their outstanding advantages such as high energy density, no risk of electrolyte leakage, and excellent thermal stability. However, the commercialization of solid-state batteries is still limited by the key technical bottleneck of poor solid-solid interface contact, which has become a core obstacle restricting the improvement of battery performance and large-scale application.

[0003] In traditional solid-state batteries, the current collector surface is mostly a smooth planar structure, which can only form a simple physical bond with the solid electrolyte and electrode active materials. Micropores and cracks easily form at the interface due to factors such as processing precision and differences in material rigidity. This problem directly leads to three core defects: First, the interface impedance increases sharply, obstructing ion transport paths and significantly reducing battery charge / discharge efficiency and rate performance; second, during charge / discharge cycles, the volume expansion and contraction of the electrode materials further exacerbates interface separation, leading to rapid capacity decay and shortened cycle life; third, the interface gaps provide space for lithium dendrite growth, and the continuous growth of lithium dendrites can easily cause internal short circuits in the battery, posing a serious safety hazard.

[0004] To improve solid-solid interface contact performance, existing technologies mainly employ interface modification, electrolyte modification, and high-voltage pressing. Interface modification improves adhesion by adding binders or buffer layers to the interface, but suffers from issues such as aging and failure of the binders and poor long-term cycle stability. While electrolyte modification optimizes interface compatibility, it often comes at the cost of sacrificing the intrinsic ionic conductivity of the electrolyte. High-voltage pressing can lead to electrode material breakage or electrolyte structure damage and cannot fundamentally eliminate interfacial porosity. Furthermore, these solutions generally suffer from complex processes, high production costs, and difficulty in adapting to large-scale production, failing to meet the comprehensive performance, cost, and safety requirements for the commercialization of solid-state batteries. Summary of the Invention

[0005] To address the above problems, this invention provides a current collector adapted to solid electrolytes, its preparation method and application, and a solid-state battery.

[0006] In a first aspect, the present invention provides a current collector adapted to a solid electrolyte, wherein the surface of the current collector is provided with a plurality of uniformly distributed protrusions and pits; wherein the average particle size d of the solid electrolyte, the pit depth H, the pit opening size D, and the protrusion height h satisfy the following relationships: Relationship 1: H is 1.2d~2.0d; Relationship 2: D is 1.5d~3.0d; Relationship 3: h is 0.5H-1.0H.

[0007] Further, the pit depth is 1.6 times the particle size of the solid electrolyte; and / or, the pit opening size is 2.4 times the particle size of the solid electrolyte; and / or, the protrusion height is 0.8 times the pit depth.

[0008] Furthermore, the average particle size d of the solid electrolyte, the pit depth H, the pit opening size D, the protrusion height h, and the distribution density ρ of the pits or protrusions satisfy the following relationship: Relationship 4: Relation 5: Relation 6: Relation 7: .

[0009] Furthermore, when d / H = 1.2, d / D is between 2.1 and 3.3; or, when d / H = 2.0, d / D is between 1.25 and 2.0.

[0010] Further, the particle size of the solid electrolyte is 10 nm-10 μm; and / or, the substrate of the current collector includes at least one of copper foil, aluminum foil, and alloy foil, and the surface roughness Ra of the substrate is ≤0.1 μm; and / or, the spacing between adjacent protrusions and the spacing between adjacent pits are both 60~400 μm; and / or, the morphology of the protrusions and the pits includes at least one of circular, square, and hexagonal shapes.

[0011] In a second aspect, the present invention provides a method for preparing a current collector adapted to a solid electrolyte as described in any one of the first aspects. The method for preparing the current collector adapted to a solid electrolyte includes the following steps: processing the surface of a molding device using a picosecond laser based on the particle size parameters of the target solid electrolyte to obtain a molding device with protrusions on its surface; forming protrusions on the surface of the molding device using a picosecond laser processing method to obtain a molding device with protrusions on its surface; and placing a current collector substrate between two molding devices with protrusions on their surfaces and rolling them to obtain the current collector.

[0012] The method for preparing a current collector adapted to solid electrolytes provided by this invention is simple to operate and has a mature process. It can be carried out according to the preparation process of micro-shaped current collectors disclosed in the prior art. It only requires setting the target parameters according to the particle size parameters of the target solid electrolyte to form protrusions and pits on the surface of the current collector that conform to the above-mentioned specific relationship.

[0013] Furthermore, the forming device includes at least one of a steel roller, a ceramic roller, and a polymer material roller.

[0014] Furthermore, the steel roller includes at least one of Q275 steel, No. 45 steel, 40Cr steel, 42CrMoAl steel and 13Cr steel, and the ceramic roller includes at least one of zirconia ceramic, alumina ceramic, silicon oxide ceramic, magnesium oxide ceramic, silicon carbide ceramic and silicon nitride ceramic.

[0015] Thirdly, the present invention provides the application of a current collector adapted to a solid-state electrolyte as described in any one of the first aspects, or a current collector prepared by the method of preparing a current collector adapted to a solid-state electrolyte as described in any one of the second aspects, in the preparation of a solid-state battery.

[0016] Fourthly, the present invention provides a solid-state battery, comprising a current collector adapted to a solid-state electrolyte as described in any one of the first aspects, or a current collector prepared by the method for preparing a current collector adapted to a solid-state electrolyte as described in any one of the second aspects.

[0017] Compared with the prior art, the above-mentioned technical solution provided by the embodiments of the present invention has at least the following advantages: The embodiments of the present invention provide a current collector adapted to solid electrolytes, its preparation method and application, and solid-state batteries. Compared with the prior art, the present invention is based on the concept of "lock-and-key matching". According to the particle size parameters of the solid electrolyte, the parameters of the pits and protrusions on the surface of the current collector are precisely designed, so that the solid electrolyte is embedded in the pits to form a "lock-and-key" mechanical interlock. This size-adaptive design fundamentally solves the solid-solid interface problem at the structural design level, completely eliminates the micropores at the interface, and increases the contact area between the electrolyte and the current collector by 3-5 times. In this way, the interfacial bonding force and ion transport efficiency are improved from the root, providing a new technical path for solving the solid-solid interface problem of solid batteries. Specifically: 1) Significantly improved interfacial bonding force: The pit and protrusion structure on the surface of the current collector enables the solid electrolyte and the current collector to form a "lock-and-key" mechanical interlock, increasing the contact area by 3-5 times and reducing the interface impedance by 60-80%, effectively solving the problem of poor solid-solid interface contact.

[0018] 2) Comprehensive optimization of battery performance: The battery energy density reaches 300-350Wh / kg, which is 30-50% higher than that of traditional solid-state batteries; the capacity retention rate is ≥85% after 2000 1C charge-discharge cycles, and the cycle stability is greatly improved; the ion transmission efficiency is improved, and it supports fast charging to 80% in 10-15 minutes.

[0019] 3) Significantly improved safety: The tight interface bonding can suppress lithium dendrite growth, and the battery does not exhibit thermal runaway during abuse tests such as extrusion and puncture, with safety performance significantly superior to traditional solid-state batteries.

[0020] 4) Simple and controllable process: It adopts mature micro-machining technology and automated equipment. The size of the micro-shape can be flexibly adjusted according to the electrolyte particle size, which is suitable for mass production. The production cost is reduced by 20-30% compared with the interface modification scheme. Attached Figure Description

[0021] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 is a schematic diagram of the processing of the molded device in this invention.

[0024] Figure 2 is a surface morphology diagram of the molded device in this invention.

[0025] Figure 3 is a schematic diagram of the fabrication of the current collector in this invention.

[0026] Figure 4 shows the surface morphology of the current collector in this invention. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. 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.

[0028] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0029] The technical problems to be solved by this invention include at least the following: 1) The solid-solid interface is not firmly bonded and the contact stability is poor: In traditional solid-state batteries, the smooth current collector and the solid electrolyte are only physically bonded in a planar manner. The pore / grid size of existing structural optimization patents (such as porous and grid-shaped current collectors) does not have a precise matching relationship with the electrolyte particle size, which makes it easy for micropores and cracks to be generated at the interface. The change in electrode volume during charge and discharge cycles will further aggravate the interface separation, making it impossible to form a stable interface bonding state.

[0030] 2) High interface impedance and low ion transport efficiency: Pores and cracks at the solid-solid interface make the ion transport path tortuous. Although existing interface modification and electrolyte modification technologies can temporarily reduce impedance, they are difficult to fundamentally eliminate interface defects, resulting in limited battery charge and discharge efficiency and rate performance, which cannot meet the requirements of high-power applications.

[0031] 3) Short cycle life and rapid performance degradation: The chemical modifiers relied upon by existing technologies are prone to aging and detachment. Physical bonding or pore filling methods cannot resist the interface degradation caused by changes in electrode volume. After long-term cycling, the battery capacity decays rapidly, making it difficult to meet the cycle stability requirements for commercial applications.

[0032] 4) Safety hazards have not been completely eliminated: The interface gap provides space for lithium dendrite growth, and the existing technology has not formed an effective inhibition at the structural level. Lithium dendrite growth is prone to cause internal short circuits in the battery; some modifiers or modified electrolytes may cause interface side reactions, increasing the risk of thermal runaway.

[0033] 5) The process is complex and costly, and the compatibility and large-scale production are difficult: Existing technologies involve multiple chemical modifications, special material deposition or composite modification processes, which require high equipment and have complicated processes; some solutions rely on special materials such as graphene and precious metal composite layers, or have compatibility problems such as insufficient electrolyte filling and hindered embedding, resulting in high production costs and difficulty in compatibility with existing battery production lines, thus limiting large-scale mass production.

[0034] The technical solution and principle provided by this invention are as follows: Based on the "key-lock matching" concept, this invention precisely designs the morphology, size, and distribution density of pits and protrusions on the current collector surface according to the particle size parameters (10nm-10μm) of the solid electrolyte. The pit depth is set to 1.2-2.0 times the particle size of the solid electrolyte to ensure that the electrolyte particles can be fully embedded in the pit to form a core bond; the pit opening size is designed to be 1.5-3.0 times the particle size, which avoids both openings that are too small and hinder electrolyte embedding, and openings that are too large and cause the bond to loosen; the protrusion height is 0.5-1.0 times the pit depth, forming a lateral constraint with the electrolyte embedded in the pit, further strengthening the structural interlocking. This size-fit design increases the contact area between the electrolyte and the current collector by 3-5 times, completely eliminating interfacial micropores.

[0035] Traditional solid-state batteries rely on physical bonding or chemical adhesion to achieve interfacial bonding, and their stability is easily affected by cycling. This invention utilizes an "embedding-constraining" mechanical interlocking structure between the pits and the electrolyte to firmly fix the electrolyte particles to the current collector surface: the pits provide longitudinal constraint to prevent electrolyte layer detachment; the protrusions form lateral support, buffering the volume expansion and contraction of the electrodes during charging and discharging, and preventing interfacial separation. The bonding force of this mechanical interlocking structure originates from the structural interlocking effect, without relying on chemical modifiers or high-pressure compression, and can maintain tight interfacial contact even during long-term cycling, significantly improving bonding stability.

[0036] Interfacial porosity and cracks are the core reasons for high ion transport resistance. In this invention, the electrolyte, embedded in the pits, forms a continuous and dense ion transport channel, eliminating the tortuous transport path of traditional interfaces. Simultaneously, the raised structure increases the contact interface between the electrolyte and the current collector, shortening the ion migration distance. Furthermore, the array-like distribution of the microstructure makes ion transport more uniform, avoiding localized current concentrations and further reducing interfacial impedance (60-80% lower than traditional batteries), thus improving battery charge / discharge efficiency and rate performance.

[0037] Lithium dendrites easily nucleate and grow at interfacial gaps, eventually leading to battery short circuits. The mechanical interlocking structure of this invention eliminates the significant gap between the electrolyte and current collector interface, depriving lithium dendrites of nucleation space. Simultaneously, the tight interfacial bonding improves the uniformity of ion concentration at the interface, preventing excessive local lithium ion deposition that could trigger dendrite growth. Furthermore, the raised structure physically blocks the continued extension of already formed micro-lithium dendrites, structurally blocking the lithium dendrite growth path and significantly improving battery safety.

[0038] Specifically, the implementation of the above technical solution is as follows: 1) Current collector pretreatment: Select copper foil, aluminum foil, or alloy foil as the current collector substrate, with a thickness controlled between 5-20 μm. Use ultrasonic cleaning to remove surface oil and impurities, with an ultrasonic power of 100-300W and a cleaning time of 10-15 min; then remove the surface oxide layer by dilute acid immersion (concentration 5-10%) or plasma treatment, with a treatment time of 5-8 min; finally, use rolling to perform surface leveling treatment, so that the surface roughness Ra of the current collector is ≤0.1 μm, to obtain a clean and flat pretreated current collector, providing a good substrate for subsequent micro-machining processing.

[0039] 2) Micro-shaped current collector processing: Based on the particle size parameters of the target solid electrolyte, the shape (circular, square or hexagonal) and size of the pits and protrusions are set through the parameter control unit.

[0040] Micro-shaped devices: Micro-shaped devices are fabricated using picosecond laser engraving micromachining technology, as shown in Figure 1. The picosecond laser is used to fabricate uniformly distributed protrusions on the surface of the device. The diameter, height, and spacing of the protrusions are at the micrometer level, with an accuracy within ±1μm. The surface morphology of the device is shown in Figure 2.

[0041] The forming devices are not limited to steel rollers (Q275 steel, No. 45 steel, 40Cr steel, 42CrMoAl steel, 13Cr steel), ceramic rollers (ZrO2 zirconia ceramic, Al2O3 alumina ceramic, Si3N4 silicon nitride ceramic, silicon oxide ceramic, MgO magnesium oxide ceramic, SiC silicon carbide ceramic) and polymer material rollers (PC polycarbonate, POM polyoxymethylene, PA polyamide) are also within the scope of this invention.

[0042] The processing parameters for the picosecond laser are shown in Table 1.

[0043] Table 1. Processing Parameters for Picosecond Lasers Protrusion height range: 2~30μm, protrusion diameter 1~80μm, protrusion spacing: 60~400μm.

[0044] Micro-shaped current collector fabrication, the fabrication of micro-porous current collector is shown in Figure 3: Current collector substrate thickness: copper foil 4~8μm, aluminum foil 9~15μm, upper and lower forming device pressure 50~400kg, protrusion or pit depth range: 0.1~20μm, protrusion or pit diameter 0.3~30μm, protrusion or pit spacing: 60~400μm.

[0045] Upper and lower molding devices are mounted on a molding equipment, with uniformly staggered protrusions on the surface of the molding devices. A pre-treated current collector is passed between the upper and lower molding devices, and pressure is applied to the molding devices to form an array of pits and protrusions on the surface of the pre-treated current collector. The depth of the pits is designed to be 1.2-2.0 times the particle size of the solid electrolyte, and the opening size is 1.5-3.0 times the particle size of the solid electrolyte to ensure sufficient embedding of the solid electrolyte. The height of the protrusions is 0.5-1.0 times the pit depth, and the pit spacing is 1-2 times the opening size to ensure structural stability. After processing, the dimensional accuracy of the microstructure is inspected using a scanning electron microscope, with the error controlled within ±1μm. The resulting surface morphology of the current collector is shown in Figure 4.

[0046] Solid electrolyte matching: The particle size distribution of the solid electrolyte was detected using a Keyence VHX-1000 ultra-depth-of-field 3D microscope, with a detection range of 10nm-10μm, to determine its average particle size and particle size distribution range. Based on the detection results, the solid electrolyte was processed into powder or slurry: Powdered electrolytes were sieved to remove large particles and ensure uniform particle size; slurry electrolytes were prepared by mixing the solid electrolyte with a dispersant (such as polyvinylpyrrolidone) at a mass ratio of 10:1-5:1, adding anhydrous ethanol or N-methylpyrrolidone to form a slurry with a solid content of 30-50%, and then stirring at high speed (2000-5000r / min) for 30-60min to ensure uniform dispersion. The processed solid electrolyte was then combined with a micro-shaped current collector by embedding an auxiliary unit, allowing the solid electrolyte to be embedded inside the pit and closely adhered to the raised surface.

[0047] Based on the physical properties of the solid electrolyte (particle size, rigidity, flexibility), the pits and protrusions on the current collector surface are designed to ensure that the microstructure forms an optimal interlocking structure with the electrolyte and achieves the best ion transport efficiency. The design is as follows: average particle size of the solid electrolyte is d (unit: nm / μm), pit depth H (unit: nm / μm, design range 1.2d~2.0d), pit opening size D (unit: nm / μm, design range 1.5d~3.0d), protrusion height h (unit: nm / μm), and pit (protrusion) distribution density ρ (unit: pieces / mm²), i.e., the number of microstructures per square millimeter; satisfying the following relationship: ; ; ; .

[0048] When d / H = 1.2, d / D needs to be between 2.1 and 3.3 to accommodate rigid oxide electrolytes (such as LLZO), reducing the difficulty of embedding through a larger opening. When d / H = 2.0, d / D needs to be between 1.25 and 2.0 to accommodate flexible polymer electrolytes (such as PEO-LiTFSI), enhancing the fixation effect through deeper recesses. For example, different recess protrusion ranges are designed for different electrolytes, as shown in Table 2.

[0049] Table 2 shows the different pit and protrusion ranges designed for different electrolytes. 4) Battery Assembly: Positive electrode active materials (such as LiNiCoMnO2, LiCoO2) are mixed with a solid electrolyte at a mass ratio of (5-7):(2-4). Conductive agents (carbon nanotubes, conductive carbon black) and binders (polyvinylidene fluoride) are added, and the mixture is stirred to form a positive electrode slurry. This slurry is then coated onto the surface of the micro-shaped current collector on the positive electrode side, with a coating thickness of 50-100 μm. The slurry is dried at 120-150℃ for 2-4 hours to form the positive electrode layer. Using a similar process, negative electrode active materials (graphite, silicon-based materials) are mixed with a solid electrolyte to form a negative electrode slurry, which is then coated onto the surface of the micro-shaped current collector on the negative electrode side to form a negative electrode layer. A solid electrolyte layer (20-50 μm thick) is coated onto the surface of the positive electrode layer. After drying, the negative electrode layer and electrolyte layer are bonded together, and the cell is formed using a stacking or winding process. The cell is then encapsulated using an aluminum-plastic film or metal casing and formed at a current density of 0.05-0.5C to form a stable solid electrolyte interface film, ultimately yielding a micro-shaped current collector solid-state battery.

[0050] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Experimental methods in the following embodiments, unless otherwise specified, are generally performed according to national standards. If no corresponding national standard exists, then generally accepted international standards, conventional conditions, or conditions recommended by the manufacturer are followed.

[0051] Example 1 This example provides a micro-shaped current collector and solid-state battery based on sulfide solid electrolyte, including the following steps: (I) Preparation of raw materials and equipment Raw materials: 12μm thick copper foil (positive electrode current collector), 8μm thick electrolytic copper foil (negative electrode current collector), sulfide solid electrolyte (Li6PS5Cl), LiNi0.6Co0.2Mn0.2O2 (NCM622, positive electrode active material), artificial graphite (negative electrode active material), carbon nanotubes (conductive agent), polyvinylidene fluoride (PVDF, binder), polyvinylpyrrolidone (PVP, dispersant), anhydrous ethanol (solvent), aluminum-plastic film (encapsulation material).

[0052] (II) Preparation steps Current collector pretreatment Select 12μm thick electrolytic copper foil (for positive electrode) and 8μm thick electrolytic copper foil (for negative electrode).

[0053] Ultrasonic cleaning: Place the current collector into the ultrasonic cleaning tank, add anhydrous ethanol as the cleaning solution, set the ultrasonic power to 200W and the frequency to 40kHz, and clean for 12 minutes to remove surface oil and dust impurities.

[0054] Oxide removal: Immerse the cleaned copper foil in a 5wt% dilute sulfuric acid solution for 6 minutes to remove the surface oxide film, then rinse with deionized water until neutral and dry with nitrogen.

[0055] Micro-machining particle size detection: The particle size distribution of sulfide solid electrolyte was detected using a picosecond laser particle size analyzer. The average particle size d was measured to be 60 nm, and the particle size distribution range was 50-80 nm.

[0056] Parameter settings: By inputting the average electrolyte particle size of 60nm through the parameter control unit of the micro-machining module, the system automatically matches the pit size parameters: the pit shape is circular, the depth H=100nm (1.7 times the particle size), the opening diameter D=100nm (1.6 times the particle size), the protrusion height h=50nm (0.5 times the pit depth), and the pit spacing L=150nm (1.5 times the opening diameter).

[0057] Micro-modeling: Utilizing a picosecond laser engraving module, with the laser energy set to 80μJ and pulse width to 20ns, a micro-protrusion is formed on the surface of the shaped device, with a height of 10μm and a diameter of 5μm. A pre-treated current collector is passed through the upper and lower shaped devices, and through rolling, an array of pits and protrusions is formed. After processing, the micro-model dimensions are inspected under a microscope, with an error ≤±1μm, meeting design requirements.

[0058] Solid electrolyte matching morphology treatment: The sulfide solid electrolyte and PVP are mixed at a mass ratio of 8:1, and anhydrous ethanol is added to prepare an electrolyte slurry with a solid content of 40wt%. The slurry is placed in the high-speed stirrer of the electrolyte treatment module, and the speed is set to 3000r / min. The mixture is stirred for 45min to ensure uniform dispersion.

[0059] Embedding Aid: The stirred electrolyte slurry is transferred to the embedding aid unit. The ultrasonic frequency is set to 40kHz and the pressure to 1MPa. The slurry is evenly sprayed onto the surface of the micro-shaped current collector through the pressure nozzle. At the same time, ultrasonic vibration is turned on to promote the electrolyte particles to be fully embedded in the pits. Excess slurry is scraped off with a scraper to form a uniform electrolyte pre-coating layer.

[0060] Battery assembly cathode preparation: NCM622: electrolyte slurry: carbon nanotubes: PVDF = 6:2:1:1 by mass ratio, add an appropriate amount of anhydrous ethanol, stir for 30 min to prepare cathode slurry, use a coating mechanism to coat it on the surface of the micro-shaped current collector on the cathode side, the coating thickness is 80 μm, put it in an oven at 130℃ and dry for 3 h to form cathode layer.

[0061] Negative electrode preparation: Artificial graphite: electrolyte slurry: carbon nanotubes: PVDF = 6:2:1:1 by mass ratio, stir for 30 min to prepare negative electrode slurry, coat it on the surface of the micro-shaped current collector on the negative electrode side, with a coating thickness of 60 μm, and dry it in an oven at 120℃ for 2 h to form a negative electrode layer.

[0062] Electrolyte layer formation: The remaining electrolyte slurry is coated onto the surface of the positive electrode layer to a thickness of 30 μm, and dried at 120°C for 1.5 h to form a dense solid electrolyte layer.

[0063] Stacking and packaging: Align and bond the negative electrode layer and electrolyte layer, assemble them into a 5cm×5cm cell using a stacking process, place them in an aluminum-plastic film, and heat seal them through a packaging unit at a temperature of 120℃, a pressure of 0.3MPa, and a time of 3s. A liquid injection port is reserved (for venting).

[0064] Formation process: The packaged cell is placed into the formation unit of the battery assembly module, the formation current is set to 0.2C, charged to 4.3V, constant voltage for 30 minutes, and then discharged to 2.8V to complete the formation, forming a stable solid electrolyte interface film and obtaining a micro-shaped current collector solid-state battery.

[0065] (III) Performance test: Electrochemical impedance: The EIS tester was used to test the battery interface impedance in the frequency range of 10mHz-1MHz. The battery interface impedance was 8.2Ω, while the interface impedance of the traditional smooth current collector solid battery was 25.6Ω, which is a 68% reduction.

[0066] Cycle life: Under 1C charge and discharge conditions (charging 4.3V, discharging 2.8V), the capacity retention rate is 88.5% after 2000 cycles, while the capacity retention rate of conventional batteries is 62.3% during the same period.

[0067] Energy density: The battery energy density reaches 322Wh / kg, which is 38% higher than that of traditional batteries.

[0068] Example 2 This example provides a micro-shaped current collector and solid-state battery based on oxide solid electrolyte, including the following steps: (I) Preparation of raw materials and equipment Raw materials: 12μm thick aluminum foil (positive electrode current collector), 8μm thick electrolytic copper foil (negative electrode current collector), oxide solid electrolyte (Li7La3Zr2O) 12 , LLZO), LiCoO2 (LCO, positive electrode active material), silicon-carbon composite material (Si / C, negative electrode active material), conductive carbon black (SμperP, conductive agent), PVDF (binder), PVP (dispersant), N-methylpyrrolidone (NMP, solvent), metal shell (encapsulation material).

[0069] (II) Preparation steps Current collector pretreatment Select 12μm thick aluminum foil (for positive electrode) and 8μm thick electrolytic copper foil (for negative electrode).

[0070] Ultrasonic cleaning: Aluminum foil was cleaned with deionized water and 0.1wt% neutral detergent as the cleaning solution, with an ultrasonic power of 250W for 10 minutes; copper foil was ultrasonically cleaned with anhydrous ethanol for 10 minutes to remove surface impurities.

[0071] Removing the oxide layer: Aluminum foil is treated with plasma at a power of 150W for 5 minutes; copper foil is soaked in 8wt% dilute sulfuric acid for 5 minutes, rinsed with deionized water until neutral, and dried with nitrogen.

[0072] Micro-machining particle size detection: Picosecond laser particle size analyzer was used to detect the particle size of LLZO electrolyte. The average particle size d=250nm, and the distribution range is 200-300nm.

[0073] Parameter settings: Input particle size 250nm to parameter control unit, matching pit parameters: square pit, depth H=400nm (1.6 times particle size), opening side length D=500nm (2.0 times particle size), protrusion height h=200nm (0.5 times pit depth), pit spacing L=800nm ​​(1.6 times opening side length).

[0074] Micro-modeling: Utilizing a picosecond laser engraving module, with the laser energy set to 100 μJ and pulse width to 15 ns, a micro-protrusion is formed on the surface of the shaped device, with a height of 20 μm and an edge of 10 μm. A pre-treated current collector is passed through the upper and lower shaped devices, and through rolling, an array of pits and protrusions is formed. After processing, the micro-model dimensions are inspected under a microscope, with an error ≤ ±1 μm, meeting design requirements.

[0075] Solid electrolyte matching and morphology treatment: LLZO electrolyte is screened through a 2000-mesh vibrating screen to remove large particle impurities, and mixed with PVP at a mass ratio of 6:1. NMP is added to make a slurry with a solid content of 45wt%. The slurry is stirred for 50 minutes at a speed of 4000r / min using a high-speed stirrer to ensure uniform dispersion.

[0076] Embedding Auxiliary: The embedding auxiliary unit is set with an ultrasonic frequency of 60kHz and a pressure of 2MPa. The slurry is sprayed onto the surface of the micro-shaped current collector. Ultrasonic vibration eliminates interface bubbles, and pressure assists the electrolyte to fill the pits. After scraping, a pre-coating layer is formed.

[0077] Battery assembly cathode preparation: LCO: electrolyte slurry: SμperP:PVDF = 7:2:0.5:0.5 by mass ratio, NMP was added and stirred for 40 min to prepare cathode slurry, which was then coated on the surface of an aluminum micro-shaped current collector with a thickness of 90 μm and dried at 140℃ for 3 h.

[0078] Negative electrode preparation: Si / C:electrolyte slurry:SμperP:PVDF = 6:3:0.5:0.5 by mass ratio, NMP was added and stirred for 40 min to prepare negative electrode slurry, which was then coated on the surface of a copper micro-shaped current collector with a thickness of 70 μm and dried at 130℃ for 2.5 h.

[0079] Electrolyte layer forming: Electrolyte slurry is coated on the surface of the positive electrode layer with a thickness of 40 μm and dried at 130℃ for 2 h.

[0080] Winding and encapsulation: The negative electrode layer and electrolyte layer are bonded together and assembled into a cylindrical battery cell (18mm in diameter and 65mm in height) using a winding process. The cell is then placed in a metal casing and encapsulated using a picosecond laser.

[0081] Formation process: Set the formation current to 0.3C, charge to 4.2V, maintain constant voltage for 20 minutes, and discharge to 3.0V to complete the formation.

[0082] (III) Performance test interface impedance: The interface impedance of the battery of the present invention is 12.5Ω, while that of the traditional smooth current collector battery is 31.8Ω, representing a 60.7% reduction in impedance.

[0083] Cycle life: After 2000 1C charge-discharge cycles, the capacity retention rate is 86.3%, while that of traditional batteries is 58.5% during the same period.

[0084] Energy density: The battery energy density reaches 341Wh / kg, which is 42% higher than that of traditional batteries.

[0085] Example 3 This example provides a micro-shaped current collector and solid-state battery based on polymer solid electrolyte, including the following steps: (I) Preparation of raw materials and equipment Raw materials: 15μm thick aluminum foil (positive electrode current collector), 8μm thick electrolytic copper foil (negative electrode current collector), polymer solid electrolyte (polyethylene oxide-lithium salt system, PEO-LiTFSI), NCM811 (positive electrode active material), hard carbon (negative electrode active material), carbon nanotubes (conductive agent), PVDF (binder), anhydrous ethanol (solvent), aluminum-plastic film.

[0086] (II) Preparation steps Current collector pretreatment: Aluminum foil and copper foil are ultrasonically cleaned (power 180W, time 15min), oxide layer is removed (aluminum foil plasma treatment for 8min, copper foil soaked in 5wt% dilute sulfuric acid for 7min), and the surface is smoothed (Ra=0.07μm) for later use.

[0087] Micro-machining: The average particle size of the polymer electrolyte is 150nm. The depth of the circular pit is set to 250nm (1.7 times the particle size), the opening diameter is set to 300nm (2.0 times the particle size), and the height of the protrusion is set to 120nm. The micro-machining structure is formed by picosecond laser technology. Then, the micro-protrusions and pits are formed on the surface of the current collector by rolling.

[0088] Electrolyte matching: The polymer electrolyte and dispersant are mixed at a mass ratio of 7:1 to prepare a slurry with a solid content of 35wt%. The slurry is then embedded into the pits using an ultrasonic frequency of 50kHz and a pressure of 1.5MPa.

[0089] Battery assembly: Positive and negative electrode active materials are mixed with electrolyte slurry at a mass ratio of 6.5:2.5, and conductive agent and binder are added to form a slurry. After coating and drying, positive and negative electrode layers are formed. The electrolyte layer thickness is 35μm. After stacking and encapsulation, it is formed at 0.1C.

[0090] (III) Performance test cycle life: After 2000 1C charge-discharge cycles, the capacity retention rate is 85.7%, while that of traditional batteries is 59.2%.

[0091] Energy density: 315Wh / kg, a 35% improvement over traditional batteries.

[0092] Comparative Example 1 This example provides a conventional solid-state battery that uses a smooth planar current collector, but does not employ the "key-lock matching" micro-model current collector design of this invention. This is a conventional technical solution in the current solid-state battery field.

[0093] Structural features: Comparative Example 2 This example provides a micro-shaped current collector and a solid-state battery. The only difference from Example 1 is that: (1) the design parameters of the current collector do not satisfy "relationship 1: H is 1.2d~2.0d"; specifically "H is 5d".

[0094] The performance test results for this example are as follows: Electrochemical impedance: Measured using an EIS instrument with a frequency range of 10mHz-1MHz, the battery interface impedance is 21.8Ω; compared to Example 1, the impedance increased by 165.9%.

[0095] Cycle life: Under 1C charge-discharge conditions (4.3V charging, 2.8V discharging), the capacity retention rate was 65.7% after 2000 cycles; compared with Example 1, the capacity retention rate decreased by 25.8%.

[0096] Energy density: The battery energy density reaches 231Wh / kg; compared with Example 1, the battery energy density decreases by 28.3%.

[0097] Conclusion: With a pit depth of H=5d, the solid electrolyte particles (d=60nm) can only fill a small portion of the space at the bottom of the pit and cannot form an effective mechanical interlock with the pit wall. A large number of micropores still exist at the interface, which leads to obstruction of ion transport paths and a significant increase in interfacial impedance.

[0098] Comparative Example 3 This example provides a micro-shaped current collector and a solid-state battery. The only difference from Example 1 is that: (1) the design parameters of the current collector do not satisfy "relationship 2: D is 1.5d~3.0d"; specifically, D=1d (d=60nm in Example 1, so D=1×60nm=60nm in this comparative example, and the other parameters are completely consistent with Example 1, namely H=100nm, h=50nm, distribution density ρ=105 cells / mm², etc.).

[0099] The performance test results for this example are as follows: Electrochemical impedance: measured using an EIS instrument with a frequency range of 10mHz-1MHz, the battery interface impedance is 23.5Ω; compared to Example 1, the impedance increased by 186.6%.

[0100] Cycle life: Under 1C charge-discharge conditions (4.3V charging, 2.8V discharging), the capacity retention rate was 63.2% after 2000 cycles; compared with Example 1, the capacity retention rate decreased by 28.6%.

[0101] Energy density: The battery energy density reaches 225Wh / kg; compared with Example 1, the battery energy density decreases by 30.1%.

[0102] Conclusion: When the pit opening size D=1d, electrolyte embedding is hindered, making it difficult for electrolyte particles to be successfully embedded inside the pit. They can only form local contact at the pit opening and cannot achieve "lock and key" mechanical interlocking. Due to insufficient filling, a large number of micropores remain at the interface, and the ion transport path is blocked by the pores, resulting in a significant increase in interface impedance.

[0103] Comparative Example 4 This example provides a micro-shaped current collector and a solid-state battery. The only difference from Example 1 is that: (1) the design parameters of the current collector do not satisfy "relationship 3: h is 0.5H-1.0H"; specifically "h is 2H" (in Example 1, H=100nm, so in this comparative example, h=2×100nm=200nm, and the other parameters are completely consistent with Example 1, namely d=60nm, H=100nm, D=100nm, distribution density ρ=105 cells / mm², etc.).

[0104] The performance test results for this example are as follows: Electrochemical impedance: Measured using an EIS instrument with a frequency range of 10mHz-1MHz, the battery interface impedance is 19.7Ω; compared to Example 1, the impedance increased by 140.2%.

[0105] Cycle life: Under 1C charge-discharge conditions (4.3V charging, 2.8V discharging), the capacity retention rate was 68.3% after 2000 cycles; compared with Example 1, the capacity retention rate decreased by 22.8%.

[0106] Energy density: The battery energy density reaches 245Wh / kg; compared with Example 1, the battery energy density decreases by 23.9%.

[0107] Conclusion: When the protrusion height h=2H, the protrusion height is too high (200nm), far exceeding the pit depth (100nm), causing the top of the protrusion to extend beyond the electrolyte layer surface after the solid electrolyte is embedded in the pit, forming a "sharp protrusion" structure. This structure will squeeze the electrolyte layer and the electrode active material layer during electrode coating and battery assembly, causing local electrolyte breakage and shedding, destroying the continuity and density of the interface, and thus causing the ion transport path to be interrupted and the interface impedance to increase significantly; Comparative Example 5 provides a micro-shaped current collector and solid battery, which differs from Example 1 only in that: (1) the design parameters of the current collector do not satisfy "relationship 4: ”; specific “ 1” In Example 1, d=60nm, H=100nm, D=100nm, and its HD / d²=(100×100) / 60²≈2.78, which is within the specified range; In this comparative example, by adjusting the pit depth H=60nm, while keeping d=60nm and D=100nm unchanged, HD / d²=(60×100) / 60²=1, the remaining parameters are completely consistent with those in Example 1, namely h=50nm, distribution density ρ=105 pieces / mm², etc.

[0108] The performance test results for this example are as follows: Electrochemical impedance: Measured using an EIS instrument with a frequency range of 10mHz-1MHz, the battery interface impedance is 24.7Ω; compared to Example 1, the impedance increased by 201.2%.

[0109] Cycle life: Under 1C charge-discharge conditions (4.3V charging, 2.8V discharging), the capacity retention rate was 62.8% after 2000 cycles; compared with Example 1, the capacity retention rate decreased by 29.0%.

[0110] Energy density: The battery energy density reaches 223Wh / kg; compared with Example 1, the battery energy density decreases by 30.7%.

[0111] Conclusion: When HD / d²=1, the core issues are concentrated on "interlocking structure failure" and "impeded ion transport": solid electrolyte particles cannot be fully embedded in the pits to form longitudinal constraints, and can only form shallow contact with the pit surface; at the same time, the insufficient compatibility of H and D means that the internal space of the pit cannot provide enough space for the electrolyte particles to be accommodated and fixed, leaving a large number of micropores at the interface, blocking the ion transport path and causing a significant increase in interface impedance; the increased interface impedance and weak interface bonding directly lead to a decrease in battery energy density, fully verifying that "relationship 4: HD / d²=2.5~4.0" is the key quantitative basis for ensuring the effectiveness of the "lock-and-key matching" structure and achieving tight interface bonding and efficient ion transport, and the precise ratio of H, D and d is the core prerequisite for improving the overall performance of the battery.

[0112] Comparative Example 6 provides a micro-shaped current collector and a solid-state battery, which differs from Example 1 only in that: (1) the design parameters of the current collector do not satisfy "relationship 5: ;"; specific " 3.8”.

[0113] The performance test results for this example are as follows: Electrochemical impedance: Measured using an EIS instrument with a frequency range of 10mHz-1MHz, the battery interface impedance is 28.6Ω; compared to Example 1, the impedance increased by 248.8%.

[0114] Cycle life: Under 1C charge-discharge conditions (4.3V charging, 2.8V discharging), the capacity retention rate was 59.8% after 2000 cycles; compared with Example 1, the capacity retention rate decreased by 32.4%.

[0115] Energy density: The battery energy density reaches 209Wh / kg; compared with Example 1, the battery energy density decreases by 35.1%.

[0116] Conclusion: When Hρ / Dh=3.8, the distribution density ρ is too high (190 pits / mm²), resulting in an excessively dense pit and protrusion structure on the current collector surface, with the spacing between adjacent pits being only 50nm (far smaller than the 150nm in Example 1). This dense structure hinders the penetration and filling of the solid electrolyte slurry. Some pits are blocked by adjacent protrusions and cannot be fully filled by the electrolyte, forming a "hollow pit" phenomenon. At the same time, the excessively dense protrusions will compress the electrolyte layer, causing electrolyte particles to break and agglomerate, disrupting the continuity of ion transport channels, and thus significantly increasing the interfacial impedance.

[0117] Various embodiments of the present invention may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of the invention; therefore, it should be considered that the range description has specifically disclosed all possible subranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the range referred to.

[0118] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A current collector adapted to solid electrolytes, characterized in that, The surface of the current collector is provided with a number of uniformly distributed protrusions and pits; wherein, the average particle size d of the solid electrolyte, the pit depth H, the pit opening size D, and the protrusion height h satisfy the following relationships: Relationship 1: H is 1.2d~2.0d; Relationship 2: D is 1.5d~3.0d; Relationship 3: h is 0.5H~1.0H.

2. The current collector adapted for solid electrolytes according to claim 1, characterized in that, The pit depth is 1.6 times the particle size of the solid electrolyte; and / or, the pit opening size is 2.4 times the particle size of the solid electrolyte; and / or, the protrusion height is 0.8 times the pit depth.

3. The current collector adapted for solid electrolytes according to claim 1, characterized in that, The average particle size d of the solid electrolyte, the pit depth H, the pit opening size D, the protrusion height h, and the distribution density ρ of the pits or protrusions satisfy the following relationship: Relationship 4: Relation 5: Relation 6: Relation 7: 。 4. The current collector adapted for solid electrolytes according to claim 3, characterized in that, When d / H = 1.2, d / D is between 2.1 and 3.3; or, when d / H = 2.0, d / D is between 1.25 and 2.

0.

5. The current collector adapted to a solid electrolyte according to any one of claims 1 to 4, characterized in that, The solid electrolyte has a particle size of 10 nm to 10 μm; and / or, the substrate of the current collector includes at least one of copper foil, aluminum foil, and alloy foil, and the surface roughness Ra of the substrate is ≤ 0.1 μm; and / or, the spacing between adjacent protrusions and the spacing between adjacent pits are both 60 to 400 μm; and / or, the morphology of the protrusions and the pits includes at least one of circular, square, and hexagonal shapes.

6. A method for preparing a current collector adapted to a solid electrolyte according to any one of claims 1 to 5, characterized in that, Includes the following steps: Based on the particle size parameters of the target solid electrolyte, a picosecond laser is used to process the surface of the molded device to obtain a molded device with protrusions on the surface. A picosecond laser is used to form protrusions on the surface of a molded device, resulting in a molded device with protrusions on its surface. A current collector substrate is placed between two molded devices with protrusions on their surfaces and rolled to obtain the current collector.

7. The method for preparing a current collector adapted to a solid electrolyte according to claim 6, characterized in that, The forming device includes at least one of steel rollers, ceramic rollers, and polymer material rollers.

8. The method for preparing a current collector adapted to a solid electrolyte according to claim 7, characterized in that, The steel roller includes at least one of Q275 steel, No. 45 steel, 40Cr steel, 42CrMoAl steel and 13Cr steel, and the ceramic roller includes at least one of zirconia ceramic, alumina ceramic, silicon oxide ceramic, magnesium oxide ceramic, silicon carbide ceramic and silicon nitride ceramic.

9. The application of a current collector adapted to a solid-state electrolyte according to any one of claims 1 to 5, or a current collector prepared by the preparation method of a current collector adapted to a solid-state electrolyte according to any one of claims 6 to 8, in the preparation of a solid-state battery.

10. A solid-state battery, characterized in that, The current collector includes the current collector adapted to a solid electrolyte as described in any one of claims 1 to 5, or the current collector prepared by the method described in any one of claims 6 to 8.

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