A high-performance functional current collector and its preparation method, electrode and battery

Abstract

This invention discloses a high-performance functional current collector and its preparation method, electrode, and battery. From the inside out, the current collector comprises a base film, a transition layer, and a copper layer. The copper layer includes an inner magnetron sputtered copper layer and an outer electroplated copper layer. The transition layer is a nickel-chromium alloy layer. Nano-alumina particles modified with silane coupling agent KH-550 are uniformly embedded in the electroplated copper layer. The surface of the KH-550 modified nano-alumina particles is grafted with amino groups. These particles are distributed in a three-dimensional network within the electroplated copper layer, accounting for 0.05% to 0.1% of the total mass. The metal layer on the base film of this functional current collector employs a composite structure of a nickel-chromium alloy transition layer, a magnetron sputtered copper layer, and an electroplated copper layer with a three-dimensional network of modified nano-alumina. This structure effectively improves the current collector's ductility and thermal stability, preventing copper layer detachment and cracking.

Description

Technical Field

[0001] This invention relates to the field of battery technology, specifically to a high-performance functional current collector and its preparation method, as well as an electrode and a battery. Background Technology

[0002] With the booming development of the new energy industry, the demand for improving the energy density, cycle life, and safety performance of batteries, as core energy storage components, is becoming increasingly urgent. Current collectors, as a key component of batteries, play a crucial role in collecting current and supporting active materials; their performance directly determines the overall performance of the battery. Currently, traditional copper and aluminum foil current collectors widely used in lithium and sodium batteries suffer from high weight and cost, severely restricting the improvement of battery energy density and cost control. To solve this problem, functional current collectors have emerged. Functional current collectors typically adopt a sandwich structure, with a polymer layer as the inner layer and metal conductive layers covering both sides. This structure, with its thin metal layer and lightweight polymer layer, effectively reduces the weight of the current collector and improves battery energy density. Simultaneously, in the event of thermal runaway, the thinner metal layer easily breaks, isolating the active material from the current collector and enhancing battery safety.

[0003] However, functional current collectors still face many challenges in practical applications. The large amount of heat generated during battery cycling causes volume changes in the functional current collector; excessive thermal shrinkage can lead to severe thermal deformation, affecting the battery's structural stability. Existing composite copper foils often use electroplating processes to thicken the copper layer, but functional current collectors prepared using traditional acid electroplating technology have significant limitations in properties such as elongation and resistivity. Specifically, the traditional electroplated copper layer has coarse and uneven grains, resulting in poor mechanical properties of the copper foil. During battery charge-discharge cycles, it is prone to cracking and detachment, which not only reduces battery cycle life but may also cause safety hazards such as short circuits. Simultaneously, higher resistivity increases the battery's internal resistance, affecting charge-discharge efficiency and energy output. Summary of the Invention

[0004] The purpose of this invention is to provide a high-performance functional current collector and its preparation method, electrode, and battery, which solves the problems of weak interlayer bonding, easy detachment and cracking of copper layer, and insufficient mechanical and thermal stability of existing current collectors.

[0005] To achieve the above objectives, the technical solution provided by the present invention is as follows: The first aspect of this application provides a high-performance functional current collector, which consists of a base film, a transition layer and a copper layer from the inside to the outside; the copper layer includes an inner magnetron sputtered copper layer and an outer electroplated copper layer. The transition layer is a nickel-chromium alloy layer, and nano-alumina particles modified with silane coupling agent KH-550 are uniformly embedded in the electroplated copper layer. The nano-alumina particles modified with silane coupling agent KH-550 have amino groups grafted on their surface, and the nano-alumina particles modified with silane coupling agent KH-550 are distributed in a three-dimensional network in the electroplated copper layer. The mass percentage of the nano-alumina particles modified with silane coupling agent KH-550 in the electroplated copper layer is 0.05%~0.1%.

[0006] To optimize the above technical solution, the specific limitations also include: The thickness of the base film is 3~5μm; the thickness of the transition layer is 30~50nm; the thickness of the magnetron sputtered copper layer is 50~80nm; the thickness of the electroplated copper layer is 0.8~1.2μm; and the particle size of the nano-alumina particles modified with silane coupling agent KH-550 is 5~10nm.

[0007] A second aspect of this application provides a method for preparing a high-performance functional current collector, comprising the following steps: S1: Pretreatment of the base film; S2: Nickel-chromium alloy layers were prepared on both sides of the pretreated base film using magnetron sputtering. S3: Magnetron sputtered copper layers are prepared on both sides of the nickel-chromium alloy layer; S4: Prepare an electroplating solution containing a composite additive system, and place the base film with a magnetron sputtered copper layer into the electroplating solution for water electroplating to prepare a water electroplated copper layer; the composite additive system consists of functionalized ionic liquid, rare earth element salt, nano-alumina particles modified with silane coupling agent KH-550 and dispersant. S5: Finally, the device is cleaned and dried to obtain a high-performance functional current collector.

[0008] In step S1, the pretreatment involves degreasing, washing, drying, and plasma treatment of the base film. The plasma treatment power is 100~150W, and the treatment time is 5~10min. In step S2, the magnetron sputtering process parameters are: sputtering power 200~250W, sputtering temperature 100~120℃, and sputtering time 15~20min.

[0009] In step S3, the process parameters for magnetron sputtering of the copper layer are: copper target purity ≥ 99.99%, sputtering power 300~350W, sputtering temperature 80~100℃, and sputtering time 10~15min.

[0010] To optimize the above technical solution, the specific measures also include: In step S4, the preparation method of nano-alumina particles modified with silane coupling agent KH-550 is as follows: Anhydrous ethanol and deionized water are mixed at a volume ratio of 9-10:1 to prepare a solvent. KH-550, weighed at 0.5%-3% of the alumina mass, is slowly added dropwise to the solvent, and the mixture is stirred for 15-30 minutes to form a silane hydrolysate. Nano-alumina powder is added to anhydrous ethanol and ultrasonically treated at 200-300W power for 20-30 minutes to form an alumina suspension. The silane hydrolysate is poured into the alumina suspension, and 0.3%-0.5% of the alumina mass of aminosilane coupling agent is added. During constant temperature stirring at 60-80℃, amino groups are grafted onto the surface of the nano-alumina particles. The nano-alumina particles modified with silane coupling agent KH-550 are separated by centrifugation at 3000-5000 r / min for 10-15 minutes and then vacuum dried.

[0011] In step S4, the electroplating solution formula is as follows: copper sulfate concentration 80~120g / L, sulfuric acid concentration 110~130g / L, hydrochloric acid concentration 50~80mg / L, and the total amount of the composite additive system added to the electroplating solution is 8~12g / L; among which, the amount of functionalized ionic liquid added is 6~8g / L, the amount of rare earth element salt added is 1.5~3g / L, the amount of nano-alumina particles modified by silane coupling agent KH-550 added is 0.5~1g / L, and the amount of dispersant added is 0.1~0.2g / L.

[0012] In step S4, the electroplating process parameters are as follows: stirring at a rate of 350~400 r / min, while using pulse current electroplating with a pulse frequency of 50~100 Hz, and electroplating time of 30~40 min, so that the nano-alumina particles can be interconnected during the copper ion deposition process to form a three-dimensional network distributed embedded in the water electroplated copper layer.

[0013] A third aspect of this application provides an electrode comprising the aforementioned high-performance functional current collector.

[0014] A fourth aspect of this application provides a battery comprising the aforementioned electrode.

[0015] Compared with the prior art, the beneficial effects of the present invention are: The metal layer on the base film of the functional current collector of this invention adopts a composite structure of a nickel-chromium alloy transition layer, a magnetron sputtered copper layer, and an electroplated copper layer. The nickel-chromium alloy transition layer effectively improves the interfacial bonding force between the base film and the copper layer, avoiding interlayer delamination. The magnetron sputtered copper layer provides a uniform and dense conductive substrate for the subsequent electroplated copper layer. The electroplated copper layer embeds KH-550 modified nano-alumina particles, and the amino groups grafted on the surface of these particles form a stable adsorption with copper ions, forming a three-dimensional network distribution in the copper layer. This can construct a continuous support skeleton, which can not only significantly improve the mechanical strength, ductility, and wear resistance of the current collector, but also refine the copper layer grains and reduce grain boundary defects, fundamentally avoiding problems such as detachment and cracking of the copper layer under the thermal and mechanical stress of battery charge and discharge cycles.

[0016] The preparation process of this invention is based on existing magnetron sputtering-electroplating production equipment, which does not require large-scale modification. It has strong process compatibility, is easy to operate, and is easy to achieve industrial mass production. Finally, by optimizing the current collector performance, the structural stability and conductivity uniformity of the electrode are further improved, thereby improving the overall performance of the battery and meeting the high-end performance requirements of the new energy industry for the core energy storage components of the battery. Detailed Implementation

[0017] The present invention will be further described in detail below through specific embodiments, but it should not be construed as limiting the scope of the subject matter of the present invention to the following embodiments. All technologies implemented based on the above content of the present invention fall within the scope of the present invention.

[0018] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, and the reagents, methods and equipment used are conventional reagents, methods and equipment in this technical field.

[0019] This invention provides a high-performance functional current collector, which consists of a base film, a transition layer and a copper layer from the inside out. The base film has a transition layer on both outer sides, and a copper layer is correspondingly disposed on the outer side of each of the two transition layers. Each copper layer includes an inner magnetron sputtered copper layer and an outer electroplated copper layer. The transition layer is a nickel-chromium alloy layer, and nano-alumina particles modified with silane coupling agent KH-550 are uniformly embedded in the electroplated copper layer. The nano-alumina particles modified with silane coupling agent KH-550 have amino groups grafted on their surface, and the nano-alumina particles modified with silane coupling agent KH-550 are distributed in a three-dimensional network in the electroplated copper layer. The mass percentage of nano-alumina particles modified with silane coupling agent KH-550 in the electroplated copper layer is 0.05%~0.1%.

[0020] This invention comprises a base film, a transition layer, and a copper layer sequentially from the inside out. The copper layer employs a dual-layer structure consisting of a magnetron sputtered copper layer and an electroplated copper layer, achieving a balance between lightweight current collector and conductivity. The transition layer uses a nickel-chromium alloy, effectively enhancing the adhesion between the base film and the copper layer, preventing issues such as copper layer detachment or peeling during battery cycling, and ensuring the structural stability of the current collector. The electroplated copper layer uniformly embeds KH-550-modified nano-alumina particles, and the amino groups grafted onto the particle surface can form stable adsorption with copper ions, promoting a three-dimensional network distribution of particles within the copper layer. This three-dimensional network structure forms a continuous supporting framework, significantly improving the mechanical strength and wear resistance of the copper layer, constructing uniform conductive channels, and optimizing the conductivity uniformity of the current collector. Simultaneously, the three-dimensional network distribution of nano-alumina particles effectively hinders copper grain growth, refines the grain structure, reduces grain boundary defects, and thus improves the ductility of the current collector, preventing it from cracking under the thermal stress of battery charge-discharge cycles. In addition, the three-dimensional network distribution of modified nano-alumina particles can enhance the thermal stability of the copper layer, suppress thermal deformation of the copper layer under high temperature environment, reduce thermal shrinkage, and provide reliable protection for the safety performance of the battery.

[0021] The thickness of the base film is 3~5μm; the thickness of the transition layer is 30~50nm; the thickness of the magnetron sputtered copper layer is 50~80nm; the thickness of the electroplated copper layer is 0.8~1.2μm; and the particle size of the nano-alumina particles modified with silane coupling agent KH-550 is 5~10nm.

[0022] The base film can be made of various commonly used polymer film materials in this field; the transition layer with a thickness of 30-50 nm ensures effective bonding between the base film and the copper layer without increasing the weight and resistance of the current collector; the 50-80 nm magnetron sputtered copper layer serves as a high-quality conductive substrate, ensuring uniform deposition of the subsequent electroplated copper layer and avoiding uneven plating; the 0.8-1.2 μm electroplated copper layer further optimizes the lightweight effect of the current collector while ensuring conductivity. The nano-alumina particles have a particle size of 5-10 nm. Particles in this size range are easier to achieve uniform dispersion and can be better embedded in the copper layer lattice. Combined with their three-dimensional network distribution characteristics, they can more fully exert the dispersion strengthening effect, further refine the copper layer grains, improve the mechanical properties and thermal stability of the current collector, and avoid internal defects in the copper layer caused by excessively large particle size, ensuring the conductivity continuity of the current collector.

[0023] This invention also provides a method for preparing a high-performance functional current collector, comprising the following steps: S1: Pretreatment of the base film; S2: Nickel-chromium alloy layers were prepared on both sides of the pretreated base film using magnetron sputtering. S3: Magnetron sputtered copper layers are prepared on both sides of the nickel-chromium alloy layer; S4: Prepare an electroplating solution containing a composite additive system, and place the base film with a magnetron sputtered copper layer into the electroplating solution for water electroplating to prepare a water electroplated copper layer; the composite additive system consists of functionalized ionic liquid, rare earth element salt, nano-alumina particles modified with silane coupling agent KH-550 and dispersant. S5: Finally, the device is cleaned and dried to obtain a high-performance functional current collector.

[0024] In step S1, the pretreatment involves degreasing, washing, drying, and plasma treatment of the base film. The plasma treatment power is 100~150W and the treatment time is 5~10min. In step S2, the magnetron sputtering process parameters are: sputtering power 200~250W, sputtering temperature 100~120℃, and sputtering time 15~20min.

[0025] In step S3, the process parameters for magnetron sputtering of the copper layer are: copper target purity ≥ 99.99%, sputtering power 300~350W, sputtering temperature 80~100℃, and sputtering time 10~15min.

[0026] In step S4, the preparation method of nano-alumina particles modified with silane coupling agent KH-550 is as follows: Anhydrous ethanol and deionized water are mixed at a volume ratio of 9-10:1 to prepare a solvent. KH-550, weighed at 0.5%-3% of the alumina mass, is slowly added dropwise into the solvent, and the mixture is stirred for 15-30 minutes to form a silane hydrolysate. Nano-alumina powder is added to anhydrous ethanol and ultrasonically treated at 200-300W power for 20-30 minutes to form an alumina suspension. The silane hydrolysate is poured into the alumina suspension, and 0.3%-0.5% of the alumina mass of aminosilane coupling agent is added. During constant temperature stirring at 60-80℃, amino groups are grafted onto the surface of the nano-alumina particles. The nano-alumina particles modified with silane coupling agent KH-550 are separated by centrifugation at 3000-5000 r / min for 10-15 minutes and then vacuum dried.

[0027] In step S4, the electroplating solution formula is as follows: copper sulfate concentration 80~120g / L, sulfuric acid concentration 110~130g / L, hydrochloric acid concentration 50~80mg / L, and the total amount of the composite additive system added to the electroplating solution is 8~12g / L; among which, the amount of functionalized ionic liquid added is 6~8g / L, the amount of rare earth element salt added is 1.5~3g / L, the amount of nano-alumina particles modified by silane coupling agent KH-550 added is 0.5~1g / L, and the amount of dispersant added is 0.1~0.2g / L.

[0028] In step S4, the electroplating process parameters are as follows: stirring at a rate of 350~400 r / min, while using pulse current electroplating with a pulse frequency of 50~100 Hz, and electroplating time of 30~40 min, so that the nano-alumina particles can be interconnected during the copper ion deposition process to form a three-dimensional network distributed embedded in the water electroplated copper layer.

[0029] The nano-alumina particles modified with KH-550 can achieve a three-dimensional network distribution, playing a role in dispersion enhancement and thermal stability; the dispersant can further improve the dispersion uniformity of the nanoparticles, avoid particle agglomeration, and ensure that they form a uniform three-dimensional network structure in the copper layer.

[0030] The process involves several key steps. First, stirring ensures uniform distribution of all components in the electroplating solution, preventing inconsistent coating thickness due to uneven copper ion concentration. Second, it promotes the uniform dispersion of modified nano-alumina particles, providing conditions for their three-dimensional network distribution. Third, an electroplating pulse frequency of 50-100Hz effectively regulates the copper ion deposition rate, refines the grain structure, reduces grain boundary defects, and promotes the interconnection of nano-alumina particles during copper ion deposition, forming a continuous three-dimensional network support framework. Finally, controlling the electroplating time ensures the copper layer thickness remains within a reasonable range, guaranteeing both the conductivity of the copper layer and allowing the nano-alumina particles to fully embed and form a stable three-dimensional network structure. This enhances the mechanical strength, wear resistance, and thermal stability of the copper layer, reducing the risk of deformation and cracking under high temperature and cyclic stress.

[0031] The present invention also provides an electrode comprising the above-described high-performance functional current collector.

[0032] The present invention also provides a battery comprising the above-described electrode.

[0033] The technical solution of the present invention will be further described in detail below with reference to specific embodiments: Example 1 1. Base film pretreatment: A 4μm thick polypropylene (PP) base film was selected, placed in a 6% sodium hydroxide solution, ultrasonically cleaned at 55℃ for 25 min, rinsed with deionized water until neutral, and vacuum dried at 85℃ for 1.5 h; then treated with 120W plasma for 8 min. 2. Transition layer preparation: A nickel-chromium alloy transition layer was prepared on both sides of the pretreated base film using magnetron sputtering. The sputtering power was 220W, the sputtering temperature was 110℃, and the sputtering time was 18min, resulting in a transition layer with a thickness of 40nm. 3. Preparation of magnetron sputtered copper layer: A copper target with a purity of 99.99% was selected, the sputtering power was 320W, the sputtering temperature was 90℃, and the sputtering time was 12min to prepare a magnetron sputtered copper layer with a thickness of 65nm. 4. Preparation of modified nano-alumina particles: Anhydrous ethanol and deionized water were mixed at a volume ratio of 9.5:1 to prepare a solvent. KH-550 weighed at 1.75% of the alumina mass was slowly added dropwise to the solvent, and the mixture was stirred for 22 minutes to form a silane hydrolysate. 5-10 nm nano-alumina powder was added to anhydrous ethanol and ultrasonically treated at 250 W for 25 minutes to form an alumina suspension. The silane hydrolysate was poured into the alumina suspension, and 0.4% of the alumina mass of an aminosilane coupling agent was added. The mixture was stirred at 70 °C for 3 hours to graft amino groups onto the surface of the nano-alumina particles. The modified nano-alumina particles were separated by centrifugation at 4000 r / min for 12 minutes and then vacuum dried. 5. Preparation of electroplated copper layer: The electroplating solution was prepared with the following formula: copper sulfate 100 g / L, sulfuric acid 120 g / L, hydrochloric acid 65 mg / L, and a total additive system of 10 g / L; including 7 g / L functionalized ionic liquid, 2.25 g / L rare earth element salt, 0.75 g / L modified nano-alumina particles, and 0.15 g / L dispersant. Electroplating process parameters: stirring at 375 r / min, using a pulsed current with a pulse frequency of 75 Hz, and an electroplating time of 35 min, to prepare an electroplated copper layer with a thickness of 1.0 μm. The nano-alumina particles formed a three-dimensional network and were distributed and embedded in the electroplated copper layer, with a mass percentage of 0.075% in the electroplated copper layer. 6. Post-treatment: After rinsing with deionized water, soak in 0.8% benzotriazole (BTA) solution at 22℃ for 8 min, and vacuum dry at 65℃ for 35 min to obtain high-performance functional current collector copper foil.

[0034] Example 2 The difference in steps is that the thickness of the electroplated copper layer is 0.8 μm, the electroplating time is adjusted to 30 min, and the other parameters are the same as in Example 1.

[0035] Example 3 The difference in steps is that the thickness of the electroplated copper layer is 1.2 μm, the electroplating time is adjusted to 40 min, and the other parameters are the same as in Example 1.

[0036] Example 4 Difference steps: In the preparation of the transition layer, the sputtering power was 200W, the sputtering temperature was 110℃, the sputtering time was 18min, and a transition layer with a thickness of 30nm was prepared. The other parameters were the same as in Example 1.

[0037] Example 5 Difference steps: In the preparation of the transition layer, the sputtering power was 250W, the sputtering temperature was 110℃, the sputtering time was 18min, and a transition layer with a thickness of 50nm was prepared. The other parameters were the same as in Example 1.

[0038] Example 6 Difference steps: In the preparation of the magnetron sputtered copper layer, the sputtering power was 300W, the sputtering temperature was 90℃, the sputtering time was 10min, and a magnetron sputtered copper layer with a thickness of 50nm was prepared. The other parameters were the same as in Example 1.

[0039] Example 7 Difference steps: In the preparation of the magnetron sputtered copper layer, the sputtering power was 350W, the sputtering temperature was 90℃, the sputtering time was 15min, and a magnetron sputtered copper layer with a thickness of 80nm was prepared. The other parameters were the same as in Example 1.

[0040] Example 8 Differentiated steps: In the preparation of modified nano-alumina particles, the amount of KH-550 added is 0.5% of the mass of alumina, and the other parameters are the same as in Example 1.

[0041] Example 9 Difference steps: In the preparation of modified nano-alumina particles, the amount of KH-550 added was 3% of the mass of alumina, the constant temperature stirring time was extended to 4 hours, and the other parameters were the same as in Example 1.

[0042] Example 10 Difference steps: In the preparation of the electroplated copper layer, the pulse frequency is 50Hz, and the other electroplating process parameters are the same as in Example 1.

[0043] Example 11 Difference steps: In the preparation of the electroplated copper layer, the pulse frequency is 100Hz, and the other electroplating process parameters are the same as in Example 1.

[0044] Example 12 Differentiated steps: In the preparation of the electroplated copper layer, the mass ratio of modified nano-alumina particles in the electroplated copper layer is 0.05%, and its addition amount is adjusted to 0.5 g / L. The remaining parameters are the same as in Example 1.

[0045] Example 13 Differentiated steps: In the preparation of the electroplated copper layer, the mass ratio of modified nano-alumina particles in the electroplated copper layer is 0.1%, and its addition amount is adjusted to 1.0 g / L. The remaining parameters are the same as in Example 1.

[0046] Comparative Example 1 The difference in steps is that the thickness of the electroplated copper layer is 0.7 μm, the electroplating time is adjusted to 25 min, and the other parameters are the same as in Example 1.

[0047] Comparative Example 2 The difference in steps is that the thickness of the electroplated copper layer is 1.3 μm, the electroplating time is adjusted to 45 min, and the other parameters are the same as in Example 1.

[0048] Comparative Example 3 Differentiated steps: In the preparation of the transition layer, the sputtering power was 190W, the sputtering temperature was 110℃, the sputtering time was 18min, and a transition layer with a thickness of 25nm was prepared. The remaining parameters were the same as in Example 1.

[0049] Comparative Example 4 Differentiated steps: In the preparation of the transition layer, the sputtering power was 260W, the sputtering temperature was 110℃, the sputtering time was 18min, and a transition layer with a thickness of 55nm was prepared. The remaining parameters were the same as in Example 1.

[0050] Comparative Example 5 Difference steps: In the preparation of the magnetron sputtered copper layer, the sputtering power was 290W, the sputtering temperature was 90℃, the sputtering time was 10min, and a magnetron sputtered copper layer with a thickness of 45nm was prepared. The other parameters were the same as in Example 1.

[0051] Comparative Example 6 Difference steps: In the preparation of the magnetron sputtered copper layer, the sputtering power was 360W, the sputtering temperature was 90℃, the sputtering time was 15min, and a magnetron sputtered copper layer with a thickness of 85nm was prepared. The other parameters were the same as in Example 1.

[0052] Comparative Example 7 Differentiated steps: In the preparation of modified nano-alumina particles, the amount of KH-550 added is 0.4% of the mass of alumina, and the other parameters are the same as in Example 1.

[0053] Comparative Example 8 Difference steps: In the preparation of modified nano-alumina particles, the amount of KH-550 added was 4% of the mass of alumina, the constant temperature stirring time was extended to 5 hours, and the other parameters were the same as in Example 1.

[0054] Comparative Example 9 Difference steps: In the preparation of the electroplated copper layer, the pulse frequency is 40Hz, and the other electroplating process parameters are the same as in Example 1.

[0055] Comparative Example 10 Difference steps: In the preparation of the electroplated copper layer, the pulse frequency is 110Hz, and the other electroplating process parameters are the same as in Example 1.

[0056] Comparative Example 11 Differentiated steps: In the preparation of the electroplated copper layer, the mass ratio of modified nano-alumina particles in the electroplated copper layer is 0.04%, and its addition amount is adjusted to 0.4 g / L. The remaining parameters are the same as in Example 1.

[0057] Comparative Example 12 Differentiated steps: In the preparation of the electroplated copper layer, the mass ratio of modified nano-alumina particles in the electroplated copper layer is 0.15%, and its addition amount is adjusted to 1.5 g / L. The remaining parameters are the same as in Example 1.

[0058] Comparative Example 13 The difference in steps is as follows: In the preparation of the electroplated copper layer, no aminosilane coupling agent is added. The nano alumina powder is directly added to anhydrous ethanol and ultrasonically dispersed. No amino grafting modification is performed, and pulsed current electroplating is not used. As a result, the nano alumina particles are randomly dispersed in the electroplated copper layer and cannot form a three-dimensional network distribution. The other parameters are the same as in Example 1.

[0059] Comparative Example 14 Difference steps: In the preparation of the electroplated copper layer, no nano-alumina particles modified by KH-550 are added, and the rest of the electroplating solution formulation and process parameters are the same as in Example 1.

[0060] Elongation test method: Using a universal tensile testing machine, the sample is clamped between upper and lower clamps. After setting the clamp spacing, the sample is stretched at a fixed speed until it breaks. The distance the clamps move when it breaks is recorded. The elongation of the sample is calculated using the formula: (distance at break - clamp spacing) ÷ clamp spacing × 100%. Heat shrinkage test method: Using a constant temperature oven, samples cut to standard dimensions are placed inside. The test temperature and heating time are set. After heating, the samples are removed and cooled to room temperature. The dimensions of the cooled samples are measured. The heat shrinkage rate of the sample is calculated using the formula: (original length - length after heating) ÷ original length × 100%. The test results are shown in Table 1.

[0061] Table 1

[0062] Analysis of experimental conclusions: Examples 1-3 demonstrate that, within a reasonable thickness range, variations in the thickness of the electroplated copper layer moderately affect the current collector's elongation and thermal stability. When the thickness is within a reasonable range, the current collector maintains good overall performance. Comparative Examples 1 and 2 show cases where the electroplated copper layer thickness is below the lower limit and above the upper limit, respectively. Compared to the examples, both show a decrease in elongation and an increase in thermal shrinkage. Insufficient thickness leads to an incomplete copper layer structure, insufficient mechanical support, and susceptibility to breakage, resulting in increased thermal shrinkage. Excessive thickness increases internal stress in the current collector, reduces its flexibility, and affects the uniformity of heat conduction, leading to intensified thermal shrinkage.

[0063] Examples 4 and 5 demonstrate that a reasonable sputtering power can result in a suitable thickness for the transition layer, ensuring effective bonding between the base film and the copper layer, thereby giving the current collector good ductility and thermal stability. In Comparative Examples 3 and 4, the sputtering power of the transition layer was too low and too high, respectively, resulting in lower ductility and higher thermal shrinkage rates compared to the corresponding examples. Insufficient power leads to insufficient transition layer thickness and loose deposition, failing to effectively bond the base film and copper layer, resulting in weak interlayer bonding and easy delamination. Excessive power results in an overly thick transition layer, increasing the current collector's resistance and generating excessive deposition stress, leading to decreased flexibility and poorer thermal stability of the current collector.

[0064] Examples 6 and 7 employ different magnetron sputtering copper layer powers. A suitable sputtering power can produce a magnetron sputtered copper layer of reasonable thickness, providing a high-quality conductive substrate for subsequent electroplated copper layers and ensuring the overall performance of the current collector. Comparative Examples 5 and 6 show that the magnetron sputtering copper layer powers are too low and too high, respectively, resulting in a significant decrease in elongation and a significant increase in thermal shrinkage. Too low a power leads to insufficient thickness and poor conductivity of the magnetron sputtered copper layer, failing to provide a uniform deposition substrate for the electroplated copper layer and causing poor bonding. Too high a power results in an excessively thick magnetron sputtered copper layer, increasing the weight and resistance of the current collector, while also generating internal stress, reducing its elongation and thermal stability.

[0065] Examples 8 and 9 both achieved effective modification of the nano-alumina particles, successfully grafting amino groups onto their surface to ensure their dispersion in the electroplated copper layer, thereby improving the overall performance of the current collector. Comparative Examples 7 and 8, compared to their corresponding examples, showed decreased elongation and increased thermal shrinkage. Insufficient KH-550 addition failed to achieve sufficient modification of the nano-alumina particles, resulting in insufficient amino groups on the particle surface, making aggregation easy and failing to exert a strengthening effect. Excessive addition led to over-modification, resulting in too many amino groups on the particle surface, affecting copper ion deposition, causing uneven copper layer structure, and decreased performance.

[0066] Examples 10 and 11 refine the copper layer grains by controlling the copper ion deposition rate through pulse frequency, promoting the formation of a three-dimensional network distribution of modified nano-alumina particles, thereby ensuring good current collector performance. Comparative Examples 9 and 10 show lower elongation and higher thermal shrinkage rates than their corresponding examples, indicating that exceeding the pulse frequency limit leads to poor copper layer grain structure and abnormal distribution of nano-alumina particles, thus affecting the overall performance of the current collector. Too low a pulse frequency results in excessively rapid copper ion deposition, coarse grains, increased grain boundary defects, and an inability to form a uniform three-dimensional network distribution. Too high a frequency results in excessively slow copper ion deposition, uneven copper layer deposition, which also disrupts the particle distribution and deteriorates the current collector performance.

[0067] Examples 12 and 13 demonstrate that a reasonable mass ratio allows nano-alumina particles to fully exert their dispersion strengthening and thermal stabilization effects, improving the current collector's ductility and thermal stability. Comparative Examples 11 and 12 represent cases where the mass ratio is below the lower limit and above the upper limit, respectively. Compared to the corresponding examples, both showed a significant decrease in ductility and a significant increase in thermal shrinkage. When the mass ratio is too low, the particles cannot form a continuous three-dimensional network support framework, making it difficult to exert the dispersion strengthening and thermal stabilization effects. When the mass ratio is too high, the particles are prone to agglomeration, leading to defects such as voids and cracks inside the copper layer, disrupting the continuity of the copper layer, and reducing the current collector's mechanical properties and thermal stability.

[0068] In the embodiments of this invention, the nano-alumina particles, modified with KH-550, form a stable three-dimensional network distribution in the electroplated copper layer, effectively improving the overall performance of the current collector. Comparative Example 13 did not undergo amino grafting modification of the nano-alumina particles and did not use pulsed current electroplating, resulting in the particles failing to form a three-dimensional network distribution and instead exhibiting a random dispersion. Its elongation was significantly lower than that of Example 1, and its thermal shrinkage was significantly higher, indicating that the three-dimensional network distribution of the nano-alumina particles is a key factor in improving the current collector's performance. Comparative Example 14, without the addition of modified nano-alumina particles, exhibited the lowest elongation and the highest thermal shrinkage, demonstrating that the addition of modified nano-alumina particles plays a crucial role in improving the mechanical and thermal stability of the current collector.

[0069] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent substitutions, and improvements made by those skilled in the art to the above embodiments without departing from the scope of the technical solution of the present invention, based on the technical essence of the present invention, shall still fall within the protection scope of the technical solution of the present invention.

Claims

1. A high-performance functional current collector, characterized in that, From the inside out, the layers are a base film, a transition layer, and a copper layer; the copper layer includes an inner magnetron sputtered copper layer and an outer electroplated copper layer. The transition layer is a nickel-chromium alloy layer, and nano-alumina particles modified with silane coupling agent KH-550 are uniformly embedded in the electroplated copper layer. The nano-alumina particles modified with silane coupling agent KH-550 have amino groups grafted on their surface, and the nano-alumina particles modified with silane coupling agent KH-550 are distributed in a three-dimensional network in the electroplated copper layer. The mass percentage of the nano-alumina particles modified with silane coupling agent KH-550 in the electroplated copper layer is 0.05%~0.1%.

2. The high-performance functional current collector according to claim 1, characterized in that, The thickness of the base film is 3~5μm; the thickness of the transition layer is 30~50nm; the thickness of the magnetron sputtered copper layer is 50~80nm; the thickness of the electroplated copper layer is 0.8~1.2μm; and the particle size of the nano-alumina particles modified with silane coupling agent KH-550 is 5~10nm.

3. A method for preparing the high-performance functional current collector as described in claim 1 or 2, characterized in that, Includes the following steps: S1: Pretreatment of the base film; S2: Nickel-chromium alloy layers were prepared on both sides of the pretreated base film using magnetron sputtering. S3: Magnetron sputtered copper layers are prepared on both sides of the nickel-chromium alloy layer; S4: Prepare an electroplating solution containing a composite additive system, and place the base film with a magnetron sputtered copper layer into the electroplating solution for water electroplating to prepare a water electroplated copper layer; the composite additive system consists of functionalized ionic liquid, rare earth element salt, nano-alumina particles modified with silane coupling agent KH-550 and dispersant. S5: Finally, the device is cleaned and dried to obtain a high-performance functional current collector.

4. The method for preparing a high-performance functional current collector according to claim 3, characterized in that, In step S1, the pretreatment involves degreasing, washing, drying, and plasma treatment of the base film. The plasma treatment power is 100~150W, and the treatment time is 5~10min. In step S2, the magnetron sputtering process parameters are: sputtering power 200~250W, sputtering temperature 100~120℃, and sputtering time 15~20min.

5. The method for preparing a high-performance functional current collector according to claim 3, characterized in that, In step S3, the process parameters for magnetron sputtering of the copper layer are: copper target purity ≥ 99.99%, sputtering power 300~350W, sputtering temperature 80~100℃, and sputtering time 10~15min.

6. The method for preparing a high-performance functional current collector according to claim 3, characterized in that, In step S4, the preparation method of nano-alumina particles modified with silane coupling agent KH-550 is as follows: Anhydrous ethanol and deionized water are mixed at a volume ratio of 9-10:1 to prepare a solvent. KH-550, weighed at 0.5%-3% of the alumina mass, is slowly added dropwise to the solvent, and the mixture is stirred for 15-30 minutes to form a silane hydrolysate. Nano-alumina powder is added to anhydrous ethanol and ultrasonically treated at 200-300W power for 20-30 minutes to form an alumina suspension. The silane hydrolysate is poured into the alumina suspension, and 0.3%-0.5% of the alumina mass of aminosilane coupling agent is added. During constant temperature stirring at 60-80℃, amino groups are grafted onto the surface of the nano-alumina particles. The nano-alumina particles modified with silane coupling agent KH-550 are separated by centrifugation at 3000-5000 r / min for 10-15 minutes and then vacuum dried.

7. The method for preparing a high-performance functional current collector according to claim 3, characterized in that, In step S4, the electroplating solution formula is as follows: copper sulfate concentration 80~120g / L, sulfuric acid concentration 110~130g / L, hydrochloric acid concentration 50~80mg / L, and the total amount of the composite additive system added to the electroplating solution is 8~12g / L; among which, the amount of functionalized ionic liquid added is 6~8g / L, the amount of rare earth element salt added is 1.5~3g / L, the amount of nano-alumina particles modified by silane coupling agent KH-550 added is 0.5~1g / L, and the amount of dispersant added is 0.1~0.2g / L.

8. The method for preparing a high-performance functional current collector according to claim 3, characterized in that, In step S4, the electroplating process parameters are as follows: stirring at a rate of 350~400 r / min, while using pulse current electroplating with a pulse frequency of 50~100 Hz, and electroplating time of 30~40 min, so that the nano-alumina particles can be interconnected during the copper ion deposition process to form a three-dimensional network distributed embedded in the water electroplated copper layer.

9. An electrode sheet, characterized in that: The high-performance functional current collector comprising the method described in claim 1 or 2 or any one of claims 3 to 8.

10. A battery, characterized in that: It includes the electrode sheet as described in claim 9.

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