Porous single crystal copper foil with oriented pore channel structure as well as preparation method and application of porous single crystal copper foil

Abstract

The invention discloses a porous single-crystal copper foil with an oriented pore channel structure and a preparation method and application thereof, the porous single-crystal copper foil with the oriented pore channel structure comprises a single-crystal copper foil with (111) crystal face orientation, the single-crystal copper foil is provided with a vertically penetrating pore channel, and the inner wall of the pore channel is coated with an Al2O3 layer. According to the invention, a unique three-dimensional interpenetrating network structure is constructed by combining the single crystal copper foil and the vertical orientation pore channels, the mechanical strength and the specific surface area of the copper foil are remarkably improved, the ion transmission process is greatly accelerated, the charge-discharge efficiency and the energy density of the battery are improved, the copper foil is endowed with excellent intrinsic performance by the highly ordered single crystal structure, and the service life of the battery is prolonged. A foundation is laid for improving the overall performance; the deposition direction of lithium metal can be effectively guided through the vertically-oriented pore channel design, and it is ensured that lithium is evenly distributed on the surface of the current collector; and the Al2O3 interface layer on the inner wall of the pore channel remarkably improves the interface stability between the current collector and the electrolyte, and further enhances the performance and the cycle life of the battery.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery materials technology, and in particular to a porous single-crystal copper foil with an oriented channel structure, its preparation method, and its application. Background Technology

[0002] Lithium metal anodes, due to their high theoretical specific capacity and low electrode potential, have become a key direction for realizing high-energy-density batteries. Currently, high areal capacity lithium metal anodes place high demands on current collector materials, which must simultaneously meet the following key performance indicators: high specific surface area to accelerate ion transport and ensure the battery's rapid charge and discharge performance; ultra-high mechanical strength to effectively suppress the volume expansion of lithium metal during charge and discharge, preventing current collector deformation and battery structural damage; and an oriented pore structure to induce uniform lithium deposition, avoid lithium dendrite formation, and ensure safe battery operation.

[0003] Copper foil is the most commonly used negative electrode current collector material, but existing copper foil materials cannot simultaneously meet all the above requirements, becoming a key technological bottleneck restricting the performance improvement of lithium-ion batteries. For example:

[0004] Traditional electrolytic copper foil, due to its polycrystalline structure, contains numerous grain boundaries. These grain boundaries not only weaken the mechanical strength of the copper foil (its tensile strength is typically <200 MPa), but also easily lead to foil breakage during battery charging and discharging due to stress concentration and other factors, thus seriously affecting the safety and stability of the battery. Furthermore, the polycrystalline structure is not conducive to the uniform transport of lithium ions, limiting the improvement of battery performance.

[0005] While existing commercially available porous copper foils increase the specific surface area to some extent, their disordered pore distribution fails to effectively guide the lithium metal deposition process. This makes lithium deposition uneven, leading to the growth of lithium dendrites. This significantly increases the risk of dendrites penetrating the separator and causing a short circuit in the battery, posing a serious safety hazard and significantly reducing the battery's cycle life.

[0006] Although single-crystal copper foil possesses high mechanical strength, its lack of porous structure results in insufficient specific surface area (typically <0.5 μm²). 2 / g), which is insufficient to meet the requirements of high areal capacity lithium metal anodes for ion transport and active sites, and makes it difficult to effectively improve the energy density and charge / discharge efficiency of batteries. Summary of the Invention

[0007] The main objective of this invention is to provide a porous single-crystal copper foil with an oriented channel structure, its preparation method, and its application, aiming to address the shortcomings of existing copper foils for lithium-ion batteries in terms of mechanical strength, specific surface area, lithium deposition uniformity, and cycle stability.

[0008] To achieve the above objectives, the present invention provides a porous single-crystal copper foil with an oriented channel structure, comprising a single-crystal copper foil having a (111) crystal plane orientation, wherein the single-crystal copper foil has vertically penetrating channels, and the inner wall of the channels is coated with an Al2O3 layer.

[0009] Furthermore, the thickness of the single-crystal copper foil is 20 μm.

[0010] Furthermore, the pore size of the channel is 5-50 nm, the aspect ratio is >10, and the porosity is 55-65%.

[0011] Furthermore, the thickness of the Al2O3 layer is 2–5 nm.

[0012] Furthermore, the specific surface area of ​​the porous single-crystal copper foil is 25.3 m². 2 / g.

[0013] The present invention also provides a method for preparing the above-mentioned porous single-crystal copper foil with oriented channel structure, comprising the following steps:

[0014] (1) Epitaxial growth of single-crystal copper foil:

[0015] High-purity copper target material was selected, and magnetron sputtering technology was used to grow a single-crystal copper foil with (111) crystal orientation on a (111) single-crystal silicon wafer substrate and then peel it off.

[0016] (2) Al nanosphere template assembly:

[0017] A colloidal solution of Al nanospheres was spin-coated onto the surface of a single-crystal copper foil, allowed to stand to form a liquid film, and then cleaned and dried to form a single-layer template of Al nanospheres on the surface of the single-crystal copper foil.

[0018] (3) Electrochemical dealloying treatment:

[0019] A single-crystal copper foil with an Al nanosphere monolayer template on its surface was placed in an H3PO4 solution as the working electrode, with Hg / Hg2SO4 as the reference electrode and a platinum sheet as the counter electrode, and an electrochemical dealloying treatment was performed to form vertically penetrating channels on the single-crystal copper foil.

[0020] (4) In-situ oxidation to form an Al2O3 layer:

[0021] The single-crystal copper foil after de-alloying is annealed in an air atmosphere to form an Al2O3 layer on the inner wall of the channel.

[0022] Furthermore, in step (1), the magnetron sputtering conditions are: Ar gas pressure 0.5 Pa, deposition temperature 300 °C, and deposition time 120 min. These deposition conditions ensure that the copper layer has a high degree of crystal orientation and good quality, providing a high-quality substrate for the subsequent construction of the pore structure.

[0023] Further, in step (2), the concentration of the colloidal solution of the Al nanospheres is 0.1 to 0.3 mol / L, and the solvent is an aqueous solution of ethanol, ethanol, or isopropanol.

[0024] Furthermore, in step (3), the concentration of the H3PO4 solution is 0.5M, the distance between the working electrode and the counter electrode is 1-7cm, and the applied voltage is 0.8V.

[0025] Furthermore, in step (4), the specific process of annealing is as follows: the temperature is raised to 300°C at a heating rate of 5-10°C / min, then held for 30 minutes, and then naturally cooled to room temperature.

[0026] The present invention also provides an application of the above-mentioned porous single-crystal copper foil with oriented channel structure in lithium metal anode current collectors or solid-state batteries.

[0027] The design principle and innovation of this invention are as follows:

[0028] The highly ordered single-crystal structure endows the copper foil with excellent intrinsic properties, laying the foundation for overall performance improvement. The vertically oriented channel design can effectively guide the deposition direction of lithium metal, ensuring that lithium is uniformly distributed on the current collector surface. The Al2O3 layer on the inner wall of the channel serves as an interface layer. Its introduction significantly improves the interfacial stability between the current collector and the electrolyte, effectively suppresses the occurrence of side reactions, and further enhances the battery's performance and cycle life. By combining the single-crystal copper foil and the vertically oriented channels, a unique three-dimensional interpenetrating network structure is constructed, which significantly improves the mechanical strength and specific surface area of ​​the copper foil, greatly accelerates the ion transport process, and improves the battery's charge and discharge efficiency and energy density.

[0029] I. Structural Design Innovation:

[0030] 1.1 Preferred Orientation and Defect Control of Single-Crystal Copper Foil

[0031] This invention is the first to apply single-crystal copper foil with (111) crystal orientation to lithium-ion battery current collectors. By precisely controlling the vapor deposition process parameters, a single-crystal copper layer was successfully grown on a (111) single-crystal silicon substrate. This highly ordered crystal structure endows the copper foil with excellent intrinsic properties, with a tensile strength of 1.52 GPa, which is significantly improved compared to traditional polycrystalline copper foil. This effectively suppresses the copper foil breakage problem caused by stress concentration during battery charging and discharging, and greatly enhances the stability of the electrode structure.

[0032] 1.2 Precise Construction of Vertically Oriented Channels

[0033] Overcoming the limitations of the disordered pore distribution in traditional porous copper foil, this invention constructs a unique vertically oriented pore structure. The pore size is precisely controlled within 5-50 nm, with an aspect ratio >10 and a porosity reaching 60%. Characterization using focused ion beam scanning electron microscopy (FIB-SEM) shows a vertical orientation degree of >99%, forming regular "ion transport channels." This structural design enables the copper foil to achieve a specific surface area of ​​up to 25.3 m². 2 / g, which is the traditional porous copper foil (0.8m) 2 The active sites are 31.6 times that of copper foil (g), providing more than 50 times the number of active sites for lithium deposition. This significantly accelerates the ion transport process and effectively reduces the lithium deposition overpotential to <20mV, which is 75% lower than that of traditional copper foil (>80mV). This ensures uniform lithium deposition on the current collector surface and fundamentally inhibits the growth of lithium dendrites.

[0034] 1.3 Integration of Functional Al2O3 Interface Layer

[0035] A 2-5 nm amorphous Al₂O₃ interface layer is uniformly coated onto the inner wall of the pores, providing a stable interfacial bridge between the current collector and the electrolyte. Residual Al is converted to Al₂O₃ through in-situ oxidation and annealing in air at 300°C for 30 min. The interfacial impedance between this interface layer and the sulfide electrolyte Li₆PS₅Cl is <3 Ω·cm. 2 Compared to traditional copper foil (>10Ω·cm) 2 The degradation rate was reduced by 70%, effectively suppressing the occurrence of side reactions and enhancing the blocking effect on lithium dendrites, resulting in a pore filling rate of >98%, which further improved the safety and cycle stability of the battery.

[0036] II. Innovation in Preparation Process:

[0037] 2.1 Epitaxial Growth Process of Single Crystal Substrates

[0038] A single-crystal copper layer was grown on a (111) single-crystal silicon substrate using vapor deposition technology. This process abandons the traditional electrochemical deposition method for polycrystalline copper foil, ensuring the single-crystal structure of the copper foil from the source. By precisely controlling parameters such as Ar gas pressure, temperature, and deposition time, the full width at half maximum (FWHM) of the diffraction peaks of the (111) crystal plane of the obtained single-crystal copper foil was only 0.08°, exhibiting high crystal orientation and good quality, providing a high-quality substrate for the subsequent construction of channel structures.

[0039] 2.2 Nanosphere Template-Dealloying Technology

[0040] Template Assembly: Using Al nanospheres as a template agent, a colloidal solution of Al nanospheres is spin-coated onto the surface of a single-crystal copper foil using self-assembly technology to form a single-layer uniform Al nanosphere template. By adjusting the template agent concentration, precise control of porosity can be achieved, laying the foundation for the formation of a regular pore structure.

[0041] Selective etching: The assembled template single-crystal copper foil is subjected to electrochemical dealloying treatment, which selectively dissolves Al nanospheres and forms vertical channels on the single-crystal copper foil. The principle of channel formation lies in the combined effect of the vertical distribution characteristics of the template and the directional dissolution effect of the electrochemical dealloying process. The vertical distribution of Al nanospheres in the template provides a "guide" for channel penetration. The Al nanospheres form a "uniform single-layer template" through self-assembly technology, and the Al nanospheres in the template are in close contact with the surface of the single-crystal copper foil, with their distribution direction perpendicular to the copper foil surface (as a "pre-made trajectory" for subsequent channels). This ordered, vertically distributed structure allows the Al nanospheres to dissolve gradually from the surface inwards (guided by the vertical distribution of the template), and with sufficient processing time, the dissolution process can penetrate the entire 20 μm thick single-crystal copper foil, ultimately forming vertically continuous channels. Furthermore, Al's electrochemical activity is higher than Cu's; under a set voltage, Al nanospheres are preferentially corroded and dissolved, while the single-crystal copper foil substrate, due to its higher chemical stability, is almost undissolved, ensuring that dissolution occurs only in the region containing the Al nanospheres. Moreover, the single-crystal copper foil has a (111) crystal orientation, resulting in a highly uniform structure, avoiding the uneven dissolution rate problems caused by grain boundaries and defects in polycrystalline materials. This uniformity ensures that the dissolution of Al nanospheres occurs synchronously along the thickness of the copper foil, ultimately forming through-holes rather than localized holes of varying depths.

[0042] In-situ oxidation: During the annealing process, the Al remaining in the pores undergoes an oxidation reaction, forming a uniform Al2O3 interface layer in situ on the inner wall of the pores. This innovative process combines template removal with the interface layer formation process, simplifying the preparation procedure while ensuring the quality stability of the pore structure and the interface layer.

[0043] The beneficial effects of this invention are reflected in:

[0044] I. Performance Breakthrough:

[0045] 1. Superior mechanical stability and flexibility

[0046] The porous monocrystalline copper foil of this invention, with its oriented channel structure, achieves a tensile strength of 1.52 GPa, which is 8.4 times that of traditional polycrystalline copper foil. It exhibits no cracks after 100,000 bending cycles and can withstand the stress generated by the volume expansion of lithium metal, preventing electrode structure failure. It effectively resists the stress caused by the volume change of lithium metal during battery charging and discharging, maintaining structural integrity. The vertically oriented channel porous structure also gives the copper foil a high specific surface area (25.3 μm²). 2With its lightweight characteristics (31 times higher than traditional copper foil), it provides structural support for high-energy-density batteries. Compared to traditional copper foil, it provides more than 50 times more active sites for lithium deposition, greatly accelerating the ion transport process and improving the battery's charge and discharge efficiency and energy density.

[0047] 2. Lithium deposition uniformity and dendrite suppression

[0048] The vertically oriented structure with an aspect ratio >10 forms an "ion transport channel," reducing the lithium deposition overpotential to <20mV (a 75% reduction). In-situ XRD shows a lithium deposition depth uniformity deviation of <2% and a pore filling rate >98%, effectively suppressing the risk of dendrite penetration. A 2-5nm Al₂O₃ interface layer on the inner wall of the pores further stabilizes the solid-liquid interface, with an interfacial impedance of <3Ω·cm with the sulfide electrolyte Li₆PS₅Cl. 2 It reduces costs by 70% compared to traditional copper foil.

[0049] In addition, the porous structure of monocrystalline copper foil can effectively reduce the weight of copper foil, thereby reducing the weight of the battery and increasing the energy density of the battery.

[0050] II. Advantages of the preparation process

[0051] 1. Precise and controllable large-scale production: The two-step epitaxial growth-dealloying method achieves consistent production with pore size distribution CV < 5% and channel orientation > 99% through precise control of template agent concentration and in-situ oxidation temperature, overcoming the defects of uneven pore size in traditional template methods. Roll-to-roll production speed > 3m / min, cost reduction of 40% compared to traditional single-crystal copper foil, and compatibility with existing battery current collector production lines.

[0052] 2. Process compatibility and environmental friendliness: The electrochemical dealloying step uses 0.5M H3PO4 electrolyte to avoid toxic reagents. Air annealing in-situ oxidation of Al2O3 does not require additional coating processes, simplifying the process while reducing energy consumption and meeting the requirements of green manufacturing.

[0053] III. Comprehensive Advantages of High-Cycle-Rate Lithium-ion Battery Applications

[0054] 1. Long lifespan and high safety: Using the porous single-crystal copper foil of this invention as a lithium metal anode current collector, an areal capacity >5mAh / cm² can be achieved. 2 Far exceeding traditional current collectors (<3mAh / cm³) 2 ), 5mA / cm 2The battery retains over 95% of its capacity after 500 cycles, representing five times the lifespan of traditional porous copper foil. During puncture testing, the battery temperature remained below 50°C, and it withstood 5000 90° bends without short circuits. Its excellent flexibility and mechanical stability meet the safety requirements of batteries in complex operating environments (such as wearable devices and implantable medical devices). In-situ XRD monitoring revealed that during battery charging and discharging, lithium deposition depth on the porous single-crystal copper foil was uniform, with a pore filling rate exceeding 98%, effectively suppressing lithium dendrite growth and significantly improving battery safety and cycle stability.

[0055] 2. Breakthrough in Solid-State Battery Compatibility: The solid-state battery assembled with the sulfide electrolyte (Li6PS5Cl) retains 92.3% of its capacity after 200 cycles at 0.5C rate at room temperature and 88.5% after 150 cycles at 60℃, significantly outperforming traditional copper foil solid-state batteries (capacity retention <70% after 100 cycles at 60℃). The interface contact angle is reduced from 65° to 28°, promoting electrolyte wetting and ion conduction. S element diffusion is reduced by 70%, effectively promoting electrolyte wetting and lowering interface impedance. Furthermore, the porous single-crystal copper foil exhibits excellent interface performance, with an interface impedance <3Ω·cm. 2 Compared to traditional current collectors (>10Ω·cm) 2 The cost has been significantly reduced, effectively improving the charging and discharging efficiency and overall performance of solid-state batteries.

[0056] IV. The Industrial Value of Technological Innovation

[0057] This invention, through a ternary structure design of "single-crystal copper foil + oriented channels + ceramic interface," breaks through the performance constraints of traditional current collectors in terms of "strength-specific surface area-interface stability," providing a core material solution for high-energy-density lithium batteries. Calculations show that battery systems using this copper foil can achieve an energy density exceeding 350Wh / kg, enabling new energy vehicles to exceed 1000 kilometers of driving range, while simultaneously reducing battery cycle degradation costs, demonstrating significant economic and social benefits.

[0058] The manufacturing process of this invention is highly compatible with continuous roll-to-roll production equipment, achieving a production speed >3m / min, a significant improvement compared to the traditional single-crystal copper foil production speed (0.5m / min). By forming an Al2O3 layer through in-situ oxidation, an additional coating process is replaced, effectively shortening the manufacturing cycle. While ensuring high performance, it possesses the potential for large-scale industrial production, effectively resolving the contradiction between performance, cost, and production capacity for high-performance current collectors, and providing strong support for industrial applications. Furthermore, this process has low energy consumption, is environmentally friendly, and meets the requirements of sustainable development. Attached Figure Description

[0059] Figure 1This is a scanning electron microscope image of the porous single-crystal copper foil with oriented channel structure prepared in Example 1.

[0060] Figure 2 The image shows the X-ray diffraction pattern of the porous single-crystal copper foil with oriented channel structure prepared in Example 1.

[0061] Figure 3 This is a SEM cross-sectional view of the porous single-crystal copper foil with oriented channel structure prepared in Example 1.

[0062] Figure 4 The image shows the EBSDIPF pattern of the porous single-crystal copper foil with oriented channel structure prepared in Example 1.

[0063] Figure 5 The image shows the AFM pattern of the porous single-crystal copper foil with oriented channel structure prepared in Example 1.

[0064] Figure 6 The images shown are HRTEM and FFT images of the porous single-crystal copper foil with oriented channel structure prepared in Example 1.

[0065] Figure 7 XRD pattern of copper foil prepared at an annealing temperature of 350°C.

[0066] Figure 8 This is a schematic diagram illustrating the application of porous single-crystal copper foil in lithium-ion batteries. Detailed Implementation

[0067] For high areal capacity lithium metal anodes, an ideal current collector needs to simultaneously meet the following key performance requirements:

[0068] 1. High specific surface area: A larger specific surface area can provide more active sites, accelerate the lithium ion transport rate, and promote the uniform deposition of lithium metal, thereby improving the battery's charge and discharge efficiency and rate performance.

[0069] 2. Ultra-high mechanical strength: During the charging and discharging process of lithium metal batteries, lithium metal undergoes significant volume expansion and contraction (volume change rate can reach over 400%). This requires the current collector to possess ultra-high mechanical strength to effectively suppress the volume expansion of lithium metal, prevent deformation and breakage of the current collector, and ensure the integrity and stability of the battery structure.

[0070] 3. Orientation channels: Ordered orientation channels can provide a clear direction and space for lithium metal deposition, guide the uniform diffusion of lithium ions, induce uniform lithium metal deposition, avoid the growth of lithium dendrites, and thus improve the safety and cycle life of the battery.

[0071] To address the aforementioned problems, this invention provides a porous single-crystal copper foil with an oriented channel structure, its preparation method, and its applications. To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0072] Unless otherwise specified, the raw materials, reagents or devices used in the following embodiments can be obtained from conventional commercial sources or by existing known methods; unless otherwise specified, the methods used in the embodiments of the present invention are methods mastered by those skilled in the art.

[0073] Example 1

[0074] Preparation of porous single-crystal copper foil with oriented channel structure

[0075] (1) Growth of single-crystal copper foil

[0076] A copper layer was deposited on a clean (111) single-crystal silicon substrate using a 99.99% pure (4N) copper target via magnetron sputtering. The Ar gas pressure was set to 0.5 Pa, the deposition temperature to 300 °C, and the deposition time to 120 min. A single-crystal copper foil with (111) crystal orientation was grown on the substrate surface. After mechanical peeling (or chemical etching), a 20 μm thick single-crystal copper foil with (111) crystal orientation was obtained. The surface of the copper foil was then cleaned to remove residual substrate impurities.

[0077] (2) Preparation of Al nanosphere templates

[0078] Preparation of colloidal solution: Al nanospheres with an average particle size of 50 nm were dispersed in a solvent (a mixture of ethanol and deionized water, volume ratio 1:1) to prepare a concentration of 0.2 mg / mL. The mixture was then ultrasonically dispersed (power 400 W, time 25 min) to obtain a colloidal solution of Al nanospheres.

[0079] Spin coating and static curing: Fix the single-crystal copper foil on the spin coater stage, and apply 25 μL / cm according to the copper foil size (e.g., 3cm × 3cm). 2 A colloidal solution of Al nanospheres was added dropwise in a specific ratio to ensure uniform surface coverage. The spin coating speed was set to 500 rpm and continued for 30 seconds to complete the spin coating. After spin coating, the mixture was allowed to stand for 25 seconds to allow the surface tension from the slow solvent evaporation to assist further self-assembly of the Al nanospheres and stabilize the liquid film structure.

[0080] Subsequent processing: After settling, the surface of the single-crystal copper foil was immediately rinsed with ethanol (3 times the volume of the colloidal solution) to remove unbound excess colloid. The single-crystal copper foil was then placed in a 70℃ drying oven for 12 minutes to allow Al nanospheres to form an ordered monolayer template on the surface of the single-crystal copper foil.

[0081] (3) Electrochemical dealloying

[0082] Electrode system construction: A single-crystal copper foil with an assembled Al nanosphere template was used as the working electrode (effective area 3 cm²). 2 A three-electrode electrolysis system was constructed, with Hg / Hg2SO4 as the reference electrode (ensuring good contact between the salt bridge and the electrolyte to avoid interference from air bubbles in the potential measurement) and a platinum sheet (1.5 times the area of ​​the working electrode) as the counter electrode.

[0083] Electrolyte preparation and working volume: Prepare 0.5M H3PO4 electrolyte (using analytical grade reagents and deionized water with a resistance >18MΩ·cm), and set the working volume to 250mL to ensure that the electrode is completely immersed and the liquid level is at least 1cm above the template area to reduce the impact of edge effects.

[0084] Electrode spacing and placement: Adjust the distance between the working electrode and the counter electrode to 3cm, and bring the tip of the reference electrode close to the surface of the working electrode (distance <0.5cm) to reduce the ohmic voltage drop of the solution. The three electrodes are arranged in a triangular symmetrical distribution to ensure uniform current distribution.

[0085] Electrochemical parameter control: A constant voltage of 0.8V (vs Hg / Hg2SO4) was applied for 30 minutes. The potential was precisely controlled using an electrochemical workstation, and the current changes were monitored in real time (normal range 5-20mA / cm). 2 A sudden surge in current may indicate copper substrate dissolution, requiring immediate adjustment.

[0086] The electrolyte temperature is controlled at 25°C using a constant temperature water bath, while magnetic stirring at 150 rpm breaks up the diffusion boundary layer to avoid excessive differences in dissolution rates between the pore edges and the center.

[0087] Process monitoring and post-treatment: During electrolysis, observe whether there is excessive generation of bubbles (H2) on the electrode surface (if so, it may be due to excessive voltage causing copper corrosion). After the process is completed, immediately remove the working electrode and quickly rinse the surface with deionized water to remove residual electrolyte, so as to avoid the continuous reaction of residual H3PO4 in the channel. Then dry it with nitrogen for later use.

[0088] (4) In-situ oxidation

[0089] The single-crystal copper foil, after electrochemical dealloying, was removed, rinsed with deionized water to remove residual electrolyte, and then dried before being placed in an air-atmosphere annealing furnace. The annealing temperature was set to 300℃, and the temperature was increased at a rate of 5℃ / min until it reached the set temperature. The furnace was then held at this temperature for 30 minutes, followed by natural cooling to room temperature. During annealing, the small amount of residual Al within the pores reacts with oxygen in the air to form an Al₂O₃ interface layer in situ on the inner wall of the pores. This interface layer enhances the stability of the pore structure, thus completing the preparation of a porous single-crystal copper foil with an oriented pore structure.

[0090] The structural characterization of the porous single-crystal copper foil with oriented channel structure prepared in this embodiment is as follows: :

[0091] Microstructure observation: Porous single-crystal copper foil with oriented channel structure was observed using focused ion beam scanning electron microscopy (FIB-SEM), such as... Figure 1 and Figure 3 As shown, the results indicate that the copper foil has a vertically oriented channel structure with an average pore size of 50 nm and a channel depth that extends throughout the entire 20 μm thick copper foil.

[0092] Crystal structure analysis: From Figure 4 As can be seen from the EBSD IPF image, the copper foil prepared by this invention has a (111) crystal plane orientation and good crystal uniformity. Furthermore, X-ray diffraction (XRD) was used to analyze the crystal structure of the porous single-crystal copper foil with the oriented channel structure, such as... Figure 2 As shown, the results indicate that the diffraction peak intensity of the (111) crystal plane accounts for >99%, and the half-peak width is only 0.08°, proving that the copper foil has a highly consistent (111) crystal plane orientation and good crystal quality.

[0093] Atomic structure analysis: such as Figure 5 As shown, AFM directly observes the atomic arrangement on the surface of a porous single-crystal copper foil with an oriented channel structure. The copper foil surface exhibits atomic-level smoothness, and sharp XRD diffraction peaks (small full width at half maximum) confirm long-range order. Polycrystalline samples show multiple peaks, while single crystals only show peaks on specific crystal planes. Additionally, as... Figure 6 As shown, HRTEM images directly image the atomic lattice, with atoms arranged regularly and continuously. FFT images show a single diffraction spot arranged regularly, which can also be interpreted as a single crystal structure.

[0094] Comparative Example 1

[0095] Preparation of traditional polycrystalline porous copper foil

[0096] This comparative example uses electrochemical deposition to prepare polycrystalline porous copper foil without single-crystallization treatment or the introduction of an Al2O3 interface layer. The preparation method is as follows:

[0097] First, an electrochemical reaction system was constructed, using a pure copper sheet as the anode and a surface-treated titanium sheet as the cathode. The electrolyte was a 0.75 mol / L copper sulfate solution, with sulfuric acid added to achieve a sulfate ion concentration of 1.3 mol / L.

[0098] Subsequently, an electric current was applied to the electrochemical reaction system, and the deposition process parameters were controlled: voltage set to 2V, temperature maintained at 30℃, deposition time at 75min, and current density maintained at 10-30mA / cm². 2 In this process, a reduction and deposition reaction of copper ions occurs at the cathode. Due to the difference in reactivity at different locations on the cathode surface, copper ions are deposited unevenly on the cathode surface, gradually forming a porous structure.

[0099] After deposition is complete, the cathode is removed, rinsed repeatedly with deionized water to remove residual electrolyte on the surface, then dehydrated with anhydrous ethanol, and finally dried in a vacuum oven at 70°C for 1.5 hours to obtain a traditional polycrystalline porous copper foil.

[0100] Comparative Example 2

[0101] Preparation of non-porous single-crystal copper foil

[0102] This comparative example uses vapor deposition to prepare a single-crystal copper foil with (111) crystal plane orientation, without a porous structure and without introducing an Al2O3 interface layer. The preparation method is the same as step (1) in Example 1.

[0103] Comparative Example 3

[0104] Preparation of disordered porous single-crystal copper foil (traditional template method)

[0105] This comparative example uses a disordered nanosphere template to prepare porous single-crystal copper foil, without controlling the pore orientation or introducing an Al2O3 interface layer. The preparation method is as follows:

[0106] First, silica nanospheres with a particle size in the range of 50-500 nm were selected and dispersed in ethanol to prepare a colloidal solution with a concentration of 0.1 mol / L. The solution was then spin-coated at a rate of 25 μL / cm². 2 The proportion was uniformly applied to the surface of the prepared single-crystal copper foil with (111) crystal orientation (prepared according to the method of Example 1), the spin coating speed was set to 2000 r / min, the spin coating time was 45s, and it was left to stand for 25s, so that the nanospheres were randomly stacked on the surface of the single-crystal copper foil to form a disordered nanosphere template layer.

[0107] Subsequently, a single-crystal copper foil with a disordered nanosphere template layer was placed in an electrochemical reaction cell, using the copper foil as the cathode and a pure copper sheet as the anode. The electrolyte was a 0.8 mol / L copper sulfate solution, with sulfuric acid added to achieve a sulfate ion concentration of 1.5 mol / L. A voltage of 1.5 V was applied, and the deposition time was set to 20 min. During this process, copper ions underwent reduction deposition at the gaps between the nanospheres, gradually filling the voids. Due to the disordered distribution of the nanosphere template, the deposited copper structure also exhibited a disordered state.

[0108] After deposition, the copper foil is immersed in a 5 wt% hydrofluoric acid solution for 10 min at room temperature, then washed and dried in a vacuum oven at 70°C for 1.5 h to obtain disordered porous single crystal copper foil.

[0109] Experimental Example 1

[0110] Performance testing of copper foils prepared in Example 1 and Comparative Examples 1-3

[0111] The test items and test methods are as follows:

[0112] Crystal structure testing: X-ray diffractometer was used to test the 10mm×10mm sample in the diffraction angle range of 20°-90°. The crystal structure, crystal plane orientation and crystal quality were determined based on the characteristic diffraction peaks.

[0113] Pore ​​structure testing: A 1mm×1mm sample was observed using a focused ion beam scanning electron microscope. Three-dimensional information of the pores was obtained by cross-sectional cutting to determine their shape, distribution, and related parameters.

[0114] Orientation test of pores: A 5mm×5mm polished sample was scanned using a scanning electron microscope equipped with an electron backscatter diffractometer. The angle between the pore axis and the surface normal was calculated, and the proportion of pores with an angle <5° was counted.

[0115] Areal capacity test: Coin cells are assembled using copper foil as current collectors. After static and charge-discharge tests, the areal capacity is calculated based on the discharge capacity and the effective area of ​​the electrodes.

[0116] Specific surface area test: The specific surface area of ​​the copper foil was tested using the nitrogen adsorption-desorption method (BET).

[0117] Specific surface area test: Approximately 50 mg of sample was weighed and degassed under vacuum at 150 °C for 3 h. The nitrogen adsorption isotherm was measured in liquid nitrogen using a specific surface area and pore size analyzer, and the specific surface area was calculated using the BET equation.

[0118] Pore ​​size distribution test: Select multiple 1mm×1mm samples, take images using FE-SEM, measure the diameter of at least 100 pores, and statistically analyze the average pore size and distribution variation coefficient to characterize the pore size distribution.

[0119] Dendrite suppression effect test: Assemble symmetrical cells, observe the lithium surface morphology and calculate the pore filling rate using SEM after cycling, then charge the cells to 50% SOC and record the temperature to evaluate the dendrite suppression effect.

[0120] Mechanical property testing: The tensile strength of the copper foil is tested using a tensile testing machine.

[0121] Lithium deposition performance testing: In a standard lithium-ion battery testing system, the lithium deposition overpotential and cycle life are tested when copper foil is used as the negative electrode current collector.

[0122] Interfacial impedance testing: Electrochemical impedance spectroscopy (EIS) was used to test the interfacial impedance between the copper foil and the electrolyte.

[0123] Pore ​​filling rate and lithium metal surface morphology observation: The surface morphology of lithium metal after cycling was observed using scanning electron microscopy (SEM). At a current density of 1 mA / cm²... 2 The symmetric cell was subjected to 100 charge-discharge cycles using an electrochemical testing system, and the pore filling rate was calculated using the coulombic efficiency. The specific calculation method was: Coulombic efficiency = Discharge capacity / Charge capacity × 100%. After multiple cycles, the pore filling rate was obtained by comparing the integral of the coulombic efficiency with the theoretical value.

[0124] The test results are shown in Table 1:

[0125] Table 1

[0126]

[0127] As can be seen from the above:

[0128] Crystal structure and mechanical properties: The present invention adopts a single crystal structure with (111) crystal plane orientation, which enables the tensile strength to reach 1.52 GPa, which is significantly higher than the polycrystalline porous copper foil of Comparative Example 1 (0.18 GPa) and the disordered porous single crystal copper foil of Comparative Example 3 (0.8 GPa). This demonstrates the great advantage of single crystal structure in improving mechanical strength and can better cope with the volume change during the charging and discharging process of lithium metal anode.

[0129] Specific surface area and ion transport: This invention achieves 25.3m through a vertically oriented pore structure. 2 The battery boasts an ultra-high specific surface area of ​​31.6 times, 84 times, and 21 times that of comparative examples 1, 2, and 3, respectively. This high specific surface area provides abundant active sites for lithium deposition, significantly reducing the lithium deposition overpotential to <20mV, far lower than other comparative examples. This effectively improves ion transport efficiency and ensures the battery's rapid charge and discharge performance.

[0130] Pore ​​structure and dendrite suppression: The disordered porous structure of Comparative Example 3 resulted in a pore size distribution CV as high as 18.5%, while the present invention, through precise process control, achieved a pore size distribution CV of only 3.2%, and a channel vertical orientation degree >99%. This regular pore structure makes lithium deposition more uniform, with a pore filling rate >98%. Compared with the higher dendrite penetration rate in the comparative example, the present invention effectively suppresses lithium dendrite growth, improving battery safety and cycle stability.

[0131] Interface performance: When used with Li6PS5Cl electrolyte, the interfacial impedance of this invention is <3Ω·cm. 2 Compared to comparative examples 1, 2, and 3, the performance was reduced by 70%, 80%, and 62.5%, respectively. The Al2O3 interface layer on the inner wall of the pores played a key role in improving interfacial compatibility and reducing interfacial impedance, which helped to improve the overall performance of solid-state batteries.

[0132] Cycle life: at 5mA / cm 2 At current density, the capacity retention rate of the present invention is >95% after 500 cycles, while the cycle life and capacity retention rate of comparative examples 1, 2, and 3 are much lower than those of the present invention, which fully demonstrates the significant advantage of the present invention in improving the long-cycle performance of batteries.

[0133] Experiment Example 2

[0134] Lithium metal battery application testing

[0135] The porous single-crystal copper foil with oriented channel structure prepared in Example 1 was assembled into a lithium metal battery for battery performance testing, as detailed below:

[0136] Battery assembly: See Figure 8 Porous single-crystal copper foil serves as the negative electrode current collector in lithium-ion batteries, and is mechanically fixed to the negative electrode material and battery casing. Following conventional battery assembly processes, a LiFePO4 positive electrode and a lithium metal-loaded cathode (with an areal capacity of 3 mAh / cm²) are sequentially assembled. 2 A porous single-crystal copper foil negative electrode and a Celgard separator were assembled, and a suitable electrolyte was injected to prepare an experimental lithium metal battery.

[0137] In the testing specifications, the LiFePO4 cathode is prepared by mixing the active material LiFePO4, the conductive agent Super P, and the binder PVDF in a mass ratio of 8:1:1, dispersing them in N-methylpyrrolidone (NMP) to form a slurry, coating it onto aluminum foil, drying it, rolling it, and cutting it into 14mm diameter discs. The active material loading is 1.5mg / cm³. 2 The porous single-crystal copper foil negative electrode is cut into a circular piece with a diameter of 16mm and pre-loaded with an areal capacity of 3mAh / cm². 2The lithium metal (lithium sheet thickness approximately 50μm) is used; the Celgard diaphragm is model Celgard2400, cut into 18mm diameter discs; the battery is a CR2032 coin cell, with a stainless steel casing and inert metal gaskets and springs; the electrolyte is a 1mol / L LiPF6 ethylene carbonate (EC) / dimethyl carbonate (DMC) mixed solution (volume ratio 1:1), with a moisture content <20ppm.

[0138] II. In the testing method, the cycle performance test uses the LAND battery testing system (CT2001A). The assembled battery is placed in a constant temperature environment of 25℃ for 12 hours before being subjected to charge-discharge cycle testing. The charging process is constant current charging to 3.65V (current density is 3mA / cm²). 2 and 5mA / cm 2 Then charge at a constant voltage until the current density drops to 0.05 mA / cm². 2 The discharge process involves constant current discharge to 2.5V (corresponding to the charging current density), and the charge / discharge capacity and coulombic efficiency of each cycle are recorded. For the puncture test in the safety performance test, a battery puncture testing machine and a 640×512 resolution infrared thermal imager are used. After charging the battery to 50% SOC, it is fixed on the test platform, and a 3mm diameter stainless steel needle is used to vertically puncture the center of the battery at a speed of 10mm / s. Simultaneously, the infrared thermal imager monitors the surface temperature change of the battery in real time and records the highest temperature. For the bending test, a single porous monocrystalline copper foil measuring 3cm×1cm is taken, fixed on a reciprocating bending testing machine, and the bending angle is set to 90° and the frequency to 1 time / s. After repeated bending 5000 times, a scanning electron microscope (SEM) is used to observe whether there are cracks on the surface of the copper foil.

[0139] III. Test conditions: All tests were conducted in an environment with a temperature of 25±1℃ and a relative humidity of <30%. The voltage window for cyclic testing was 2.5-3.65V, and the current density was 3mA / cm². 2 and 5mA / cm 2 The number of cycles were 300 and 500 respectively. In the safety test, the needle diameter for the puncture test was 3mm and the puncture speed was 10mm / s. In the bending test, the bending angle was 90°, the frequency was 1 time / s, and the number of cycles was 5000.

[0140] The test results are as follows:

[0141] Cyclic performance testing: The assembled battery was subjected to charge-discharge cycle tests at different current densities. The results showed that when the current density was 3mA / cm², the battery performed well. 2 At that time, after 300 cycles, the battery retained 98.2% of its capacity and achieved a coulombic efficiency of 99.8%; when the current density was increased to 5 mA / cm², the battery achieved a capacity retention of 98.2% and a coulombic efficiency of 99.8%. 2After 500 cycles, the battery capacity retention rate is still as high as 95.1%, and the coulombic efficiency is 99.5%.

[0142] Security performance testing:

[0143] Puncture test: The battery was subjected to a puncture test, and the battery temperature was monitored by an infrared thermal imager after puncture. The results showed that the battery temperature was always <50℃ and no thermal runaway occurred, indicating that the battery has good safety.

[0144] Bending test: The porous single-crystal copper foil was subjected to a 90° bending test. After repeated bending 5000 times, SEM observation showed that no cracks were generated on the surface of the copper foil, proving that it has excellent flexibility and mechanical stability.

[0145] Experimental Example 3

[0146] Solid-state battery application testing

[0147] The porous single-crystal copper foil with oriented channel structure prepared in Example 1 was assembled into a solid-state battery for battery performance testing, as detailed below:

[0148] Battery assembly: Cathode—LiNi 0.8 Co 0.1 Mn 0.1 O2 (NCM811); Anode -- Porous single-crystal copper foil loaded with lithium metal (area capacity 5mAh / cm²) 2 Electrolyte -- Li6PS5Cl sulfide electrolyte (thickness 50μm).

[0149] In terms of testing specifications, the cathode is made of LiNi 0.8 Co 0.1 Mn 0.1 O2 (NCM811), Super P, and PVDF were mixed in a mass ratio of 85:10:5 and coated onto aluminum foil. The mixture was then pressed into 12mm diameter discs by a drying roller, resulting in an active substance loading of 2.0 mg / cm³. 2 The negative electrode is a porous single-crystal copper foil from Example 1 cut into a 14mm diameter disc, with a load of 5mAh / cm². 2 Lithium metal (approximately 80 μm thick); the electrolyte is Li6PS5Cl sulfide electrolyte, pressed into a disc with a diameter of 15 mm, a thickness of 50 μm and a relative density >90%; the battery is a CR2032 coin cell solid-state battery with a stainless steel casing and nickel gaskets to ensure conductivity and sealing.

[0150] For testing methods, high-precision systems such as NEWA BTS-5V2A were used for cycle performance testing. After the battery was placed in an argon glove box (water oxygen < 0.1 ppm) for 24 h, it was charged and discharged at 0.5 C (1 C = 200 mA / g) from 3.0 to 4.3 V. After constant current charging to 4.3 V, the voltage was constant to 0.02 C, and then constant current discharge to 3.0 V. Cycling was performed at room temperature (25 °C) and high temperature (60 °C), and the capacity and coulombic efficiency were recorded. For auxiliary testing of interface performance, an electrochemical workstation such as Autolab PGSTAT302N was used. A Li|electrolyte|Li symmetric battery was assembled in a glove box. The interface impedance was measured by EIS (frequency 1 Hz-1 MHz, amplitude 10 mV). At the same time, the contact angle of the electrolyte and copper foil was measured by a contact angle meter using the seat drop method (5 μL droplet, 3 measurements and average). The wettability was evaluated by the contact angle between the electrolyte and copper foil.

[0151] The test conditions were as follows: assembly and cycling preparation were carried out in an argon glove box (water oxygen < 0.1 ppm), cycling at room temperature 25±1℃ and high temperature 60±1℃, with cycling parameters of 3.0-4.3V voltage window and 0.5C current density, 200 cycles at room temperature and 150 cycles at high temperature, and the interface test parameters were the same as those set above.

[0152] The test results are as follows:

[0153] Room temperature (25°C) cycling: 200 cycles at 0.5°C, capacity retention 92.3%, coulombic efficiency 99.1%;

[0154] High temperature (60℃) cycling: After 150 cycles at 0.5C, the capacity retention rate is 88.5%, which is significantly better than that of traditional copper foil solid-state batteries (capacity retention rate <70% after 100 cycles at 60℃).

[0155] Experiment Example 4

[0156] Experiment on the influence of process parameters

[0157] The effect of different Al nanosphere colloidal solution concentrations on pore structure was investigated: Based on Example 1, the colloidal solution concentrations of Al nanospheres were adjusted to 0.1 mol / L, 0.2 mol / L, and 0.3 mol / L, respectively, and the Al nanospheres were replaced with Al nanospheres with an average particle size of 30 nm. The electrochemical dealloying treatment time was adjusted to 20 min, and other steps and conditions were the same as in Example 1.

[0158] The effect of different in-situ oxidation reaction temperatures on the Al2O3 layer effect was studied: Based on Example 1, the set annealing temperature for in-situ oxidation was adjusted to 250℃ and 350℃ respectively, while other steps and conditions were the same as in Example 1.

[0159] The test results of the copper foil obtained under different conditions are shown in Table 2. The test method is the same as that in Experiment 1.

[0160] Table 2

[0161]

[0162]

[0163] From the table above, we can conclude that:

[0164] 1. Effect of template agent concentration: The template agent concentration has a significant impact on pore structure and performance. As the template agent concentration increases from 0.1 mol / L to 0.2 mol / L, the pore size changes little, but the porosity increases from 55% to 60%, the pore orientation increases from 95% to 98%, and the cycling performance also improves at 5 mA / cm². 2 After 500 cycles, the capacity retention rate increased from 94% to 95%. When the concentration was further increased to 0.3 mol / L, although the porosity was further improved, the excessively high concentration caused template accumulation, and the pore orientation decreased to 92%, indicating that 0.2 mol / L is the optimal template agent concentration, which can achieve an optimized balance between pore structure and performance.

[0165] 2. Effect of in-situ oxidation temperature: The oxidation temperature directly determines the quality of the Al2O3 interface layer. At 250℃, the Al2O3 layer thickness is only 1.5 nm and has poor continuity, resulting in an interface impedance as high as 4.5 Ω·cm. 2 The battery cycle performance is poor; a 3nm uniform amorphous Al2O3 layer is formed at 300℃, and the interface impedance drops to 2.8Ω·cm. 2 The capacity retention rate reached 92.3% after 200 cycles at room temperature and 88.5% after 150 cycles at high temperature, exhibiting the best overall performance. At 350℃, the Al2O3 layer thickness increased, but an Al2O3 crystalline phase appeared, and XRD detected γ-Al2O3 peaks (e.g., ...). Figure 7 As shown in the figure, the interface impedance increases and the cycle performance decreases, indicating that 300℃ is the optimal temperature for in-situ oxidation, which can form an interface layer with excellent performance.

[0166] 3. Correlation between process parameters and performance: The table clearly shows that subtle adjustments to process parameters can have a cascading effect on the pore structure, interfacial properties, and battery cycle performance of the copper foil. Precise control of parameters such as template agent concentration and in-situ oxidation temperature is crucial for preparing high-performance porous single-crystal copper foil. This invention, through systematic research, has determined the optimal combination of process parameters, ensuring the consistency and stability of product performance.

[0167] Experimental Example 5

[0168] Solid-state battery application performance comparison

[0169] The porous single-crystal copper foil with oriented channel structure prepared in Example 1 and the conventional polycrystalline porous copper foil prepared in Comparative Example 1 were respectively assembled into solid-state batteries for battery performance testing. The testing method was the same as in Experiment 2. The test results are shown in Table 3 below:

[0170] Table 3

[0171]

[0172] As can be seen from the table above:

[0173] 1. Cyclic Performance Advantage: In solid-state battery applications, the porous monocrystalline copper foil of this invention exhibits superior cycle stability. At room temperature (25°C) and 0.5C rate, after 200 cycles, the capacity retention rate remains as high as 92.3%, while traditional copper foil solid-state batteries retain less than 70% of their capacity after 100 cycles. At high temperature (60°C) and 0.5C rate, the capacity retention rate of this invention is 88.5% after 150 cycles, far exceeding that of traditional copper foil solid-state batteries. This effectively solves the problem of poor high-temperature cycle performance in traditional solid-state batteries, significantly improving battery life and reliability.

[0174] 2. Improved Interface Performance: The copper foil of this invention reduces the electrolyte contact angle from 65° to 28° compared to conventional copper foil, indicating a significant improvement in wettability with sulfide electrolytes and promoting uniform electrolyte distribution and ion conduction within the channels. Simultaneously, the sulfur diffusion is reduced by 70%, demonstrating that the Al2O3 interface layer effectively suppresses side reactions between the electrolyte and lithium metal, stabilizes the electrode / electrolyte interface, reduces the increase in interface impedance, and thus improves the overall performance of the solid-state battery.

[0175] 3. Application Value: The excellent performance of this invention in solid-state batteries proves that it can meet the stringent requirements of high-energy-density, long-cycle-life solid-state batteries for current collectors, providing key technical support for the commercial application of solid-state batteries, and has significant industrial application value and broad market prospects.

[0176] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A porous single-crystal copper foil with an oriented channel structure, characterized in that, It includes a single-crystal copper foil with a (111) crystal orientation, wherein the single-crystal copper foil has a vertically penetrating channel, and the inner wall of the channel is coated with an Al2O3 layer.

2. The porous single-crystal copper foil with an oriented channel structure as described in claim 1, characterized in that, The thickness of the single-crystal copper foil is 20 μm.

3. The porous single-crystal copper foil with an oriented channel structure as described in claim 1 or 2, characterized in that, The pore size is 5–50 nm, the aspect ratio is >10, and the porosity is 55–65%.

4. The porous single-crystal copper foil with an oriented channel structure as described in claim 1 or 2, characterized in that, The thickness of the Al2O3 layer is 2–5 nm.

5. The porous single-crystal copper foil with an oriented channel structure as described in claim 1 or 2, characterized in that, The porous single-crystal copper foil has a specific surface area of ​​25.3 m². 2 / g.

6. The method for preparing porous single-crystal copper foil with oriented channel structure as described in any one of claims 1 to 5, characterized in that, Includes the following steps: (1) Epitaxial growth of single-crystal copper foil: High-purity copper target material was selected, and magnetron sputtering technology was used to grow a single-crystal copper foil with (111) crystal orientation on a (111) single-crystal silicon wafer substrate and then peel it off. (2) Al nanosphere template assembly: A colloidal solution of Al nanospheres was spin-coated onto the surface of a single-crystal copper foil, allowed to stand to form a liquid film, and then cleaned and dried to form a single-layer template of Al nanospheres on the surface of the single-crystal copper foil. (3) Electrochemical dealloying treatment: A single-crystal copper foil with an Al nanosphere monolayer template on its surface was placed in an H3PO4 solution as the working electrode. Hg / Hg3SO4 was used as the reference electrode and a platinum sheet was used as the counter electrode. Electrochemical dealloying was performed to form vertically penetrating channels on the single-crystal copper foil. (4) In-situ oxidation to form an Al2O3 layer: The single-crystal copper foil after de-alloying is annealed in an air atmosphere to form an Al2O3 layer on the inner wall of the channel.

7. The method for preparing porous single-crystal copper foil with oriented channel structure as described in claim 6, characterized in that, In step (1), the conditions for magnetron sputtering are: Ar gas pressure 0.5 Pa, deposition temperature 300 °C, and deposition time 120 min.

8. The method for preparing porous single-crystal copper foil with oriented channel structure as described in claim 6, characterized in that, In step (2), the concentration of the colloidal solution of the Al nanospheres is 0.1 to 0.3 mol / L, and the solvent is an aqueous solution of ethanol, ethanol, or isopropanol.

9. The method for preparing porous single-crystal copper foil with oriented channel structure as described in claim 6, characterized in that, In step (4), the specific process of annealing is as follows: the temperature is raised to 300°C at a heating rate of 5-10°C / min, then held for 30 minutes, and then naturally cooled to room temperature.

10. The application of porous single-crystal copper foil with oriented channel structure as described in any one of claims 1 to 5 in lithium metal anode current collectors or solid-state batteries.

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