Composite polymer current collector, method of making and use thereof

Abstract

The present application relates to the technical field of electrochemical energy storage device components, in particular to a composite polymer current collector, a preparation method and application thereof, the composite polymer current collector comprises a polymer base film and a metal layer arranged on at least one side surface of the polymer base film, wherein the material of the polymer base film comprises polyarylether resin containing a phthalazinone structure, the polyarylether resin containing the phthalazinone structure has the chemical structure shown in the following formula: wherein n is a positive integer. The composite polymer current collector provided by the present application can make the area density of the current collector lower by taking the polyarylether resin containing the phthalazinone structure as the base material and arranging the metal layer on the base material, thereby reducing the mass proportion of the current collector in the battery cell and improving the mass energy density of the sodium-based energy storage device.

Description

Technical Field

[0001] This invention relates to the field of electrochemical energy storage device components, and in particular to a composite polymer current collector, its preparation method, and its application. Background Technology

[0002] Driven by global "dual carbon" goals, the transformation of the energy structure towards cleaner and lower-carbon energy has become an inevitable trend, with the installed capacity of renewable energy sources such as wind and solar power continuing to climb. However, these energy sources are greatly affected by natural conditions, and their output power exhibits significant intermittency and fluctuations. Therefore, efficient energy storage technologies are needed to achieve real-time energy storage and ensure stable grid operation. Sodium-based energy storage devices, relying on abundant sodium resources, extremely low cost, and excellent low-temperature performance, have become one of the core candidate technologies for large-scale energy storage (such as grid peak shaving, base station backup power, and low-voltage energy storage systems for new energy vehicles). In recent years, sodium-based energy storage devices have made rapid breakthroughs in materials research and development, device assembly, etc. However, their core performance indicators still have significant shortcomings, especially the relatively low energy density, which has become a key bottleneck restricting their penetration into high-end energy storage scenarios (such as long-range portable energy storage and high-end new energy vehicle auxiliary energy storage).

[0003] Currently, most research in the industry aimed at improving the energy density of sodium-based energy storage devices focuses on the development and optimization of active materials in the battery cell. Researchers are continuously improving the specific capacity and electronic conductivity of active materials by controlling their crystal structure (e.g., constructing layered oxides and polyanionic compounds), optimizing their morphology (e.g., preparing nanoscale, porous particles), and doping modifications (e.g., introducing heterovalent metal ions), thereby breaking through the energy density bottleneck. It is worth noting that improving the energy density of the battery cell depends not only on the performance of the active material but also on the proportion and performance of inactive components within the cell. However, the industry currently pays very little attention to the research and development of inactive components (such as current collectors, separators, and electrolyte additives).

[0004] As a key non-active component in sodium-based energy storage devices, the current collector plays a crucial role in carrying active materials, establishing electron transport pathways, and maintaining the stability of the cell structure. Its performance and design directly determine the device's energy density, cycle life, and safety. Currently, traditional pure metal current collectors (mainly aluminum and copper foil) commonly used in sodium-based energy storage devices have a high areal density, accounting for 15% to 25% of the total cell mass. Since the current collector does not participate in electrochemical reactions and is considered "ineffective mass," its high proportion directly compresses the mass space of the active material. With a fixed total cell mass, a 5% reduction in the current collector mass proportion can increase the active material mass proportion by approximately 4% to 6%, thereby driving an 8% to 12% increase in device energy density. Therefore, the high mass proportion of traditional metal current collectors has become a significant factor restricting the lightweighting and mass-energy-density improvement of sodium-based energy storage devices.

[0005] Therefore, developing a low areal density current collector to reduce the mass ratio of the current collector in the battery cell and improve the mass energy density of sodium-based energy storage devices is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] In view of the above-mentioned shortcomings in the prior art, the purpose of this invention is to provide a composite polymer current collector, its preparation method and application. The composite polymer current collector provided by this invention uses a polyarylether resin containing a diazanaphthone structure as a substrate and sets a metal layer on the substrate, which can make the areal density of the current collector lower, thereby reducing the mass ratio of the current collector in the battery cell and improving the mass energy density of sodium-based energy storage devices.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a composite polymer current collector, the composite polymer current collector comprising a polymer base film and a metal layer disposed on at least one surface of the polymer base film, wherein the polymer base film is made of a polyarylether resin containing a diazanaphthone structure, the polyarylether resin containing a diazanaphthone structure having the following chemical structure:

[0009]

[0010] Where n is a positive integer.

[0011] Furthermore, the material of the metal layer includes at least one of aluminum and copper.

[0012] Furthermore, the thickness of the polymer-based film is 1-15 μm;

[0013] And / or, the thickness of the metal layer is 100nm-2000nm;

[0014] And / or, the number average molecular weight of the polyarylether resin containing the diazanaphthone structure is 20,000-50,000 g / mol.

[0015] In a second aspect, the present invention provides a method for preparing a composite polymer current collector as described in the first aspect, the method comprising the following steps:

[0016] The metal layer is formed on at least one surface of the polymer-based film.

[0017] Furthermore, prior to forming the metal layer, the preparation method does not include a pretreatment step on the polymer-based film aimed at increasing its surface energy;

[0018] And / or, the metal layer is formed by at least one of vapor deposition, magnetron sputtering, ion plating, and electroplating.

[0019] Furthermore, the method for preparing the polymer-based film includes the following steps:

[0020] S1. Preparation of polyarylene ether resin slurry containing a diazanaphthone structure:

[0021] Dissolve polyarylene ether resin powder containing a diazanaphthone structure in a polar solvent and stir until completely dissolved to obtain a polyarylene ether resin slurry containing a diazanaphthone structure.

[0022] S2, Film Formation:

[0023] The polyarylene ether resin slurry containing the diazanaphthone structure is subjected to film-forming treatment and post-treatment to obtain the polymer base film.

[0024] Furthermore, in step S1, the mass ratio of the polyarylene ether resin powder containing the diazanaphthone structure to the polar solvent is 1:5-15;

[0025] And / or, in step S1, the polar solvent includes one of N-methylpyrrolidone, N,N-dimethylacetamide, and chloroform;

[0026] And / or, in step S1, the stirring temperature is 80-120°C;

[0027] And / or, in step S2, the film-forming process includes: coating the slurry onto the substrate surface, drying to evaporate the polar solvent, and forming a solid film, wherein the drying is performed using a gradient temperature increase method;

[0028] And / or, in step S2, the post-processing includes: immersing the substrate with the solid film in water to detach the film from the substrate, followed by drying;

[0029] Furthermore, in step S2, the coating is performed using a blade coating method, and the gap between the bottom of the blade and the surface of the substrate is 25μm-500μm;

[0030] And / or, the substrate includes a glass plate;

[0031] And / or, before coating the slurry onto the substrate surface, the film-forming process further includes: pre-treating the substrate, the pre-treating process including: sequentially cleaning the substrate surface with deionized water and ethanol, and then drying it at 50-120°C for 10-60 minutes;

[0032] And / or, in step S2, the gradient heating method includes first holding at 60-80°C for 6-12 hours, then heating to 130-200°C at a heating rate of 2-10°C / min and holding for 12-24 hours.

[0033] Furthermore, the magnetron sputtering is vacuum magnetron sputtering, and the specific parameters of the magnetron sputtering include: the target material is either a copper target or an aluminum target; the background vacuum is 0.00001-0.01 Pa; the temperature of the magnetron sputtering chamber is 25-100 °C; the sputtering atmosphere is either nitrogen or argon; the working pressure is 0.3-10 Pa; the sputtering time is 100-3000 s; the flow rate of nitrogen or argon during magnetron sputtering is 20-70 sccm; and the sputtering power is 20-250 W.

[0034] Thirdly, the present invention provides an application of the composite polymer current collector as described in the first aspect or the composite polymer current collector prepared by the preparation method described in the second aspect in sodium-based energy storage devices, lithium-based energy storage devices or potassium-based energy storage devices.

[0035] Compared with the prior art, the beneficial effects of the present invention include at least one of the following:

[0036] (1) The composite polymer current collector provided by the present invention uses polyarylether resin containing diazanaphthone structure as substrate and sets metal layer on substrate, which can make the surface density of current collector lower, thereby reducing the mass ratio of current collector in battery cell and improving the mass energy density of sodium-based energy storage device.

[0037] (2) The composite polymer current collector provided by the present invention has a small thickness, which is much smaller than that of commercial copper foil and aluminum foil (20μm), thereby reducing the volume of inactive materials in the energy storage device and significantly improving the volumetric energy density of the energy storage device from the perspective of the device.

[0038] (3) The composite polymer current collector provided by the present invention uses polyarylether resin containing diazanaphthone structure as substrate, which can make the bonding force between the metal coating and the polymer film strong.

[0039] (4) The polyarylene ether resin containing diazanaphthone structure used in this invention has excellent thermal stability (glass transition temperature up to 350°C or higher), chemical stability, and flame retardancy, achieving a flame retardancy rating of V0, which greatly improves the safety of sodium-based energy storage devices. In addition, the unique twisted non-coplanar structure of diazanaphthone endows the resin with soluble properties, making the resin more processable and possessing the potential for large-scale production. Attached Figure Description

[0040] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0041] Figure 1 A schematic diagram of the structure of the composite polymer current collector provided by the present invention;

[0042] Figure 2 A comparison diagram of the tensile properties of the composite polymer current collector and the polyarylether resin film prepared in Example 3 of the invention;

[0043] Figure 3 SEM image (left) and EDS spectrum (right) of the composite polymer current collector prepared in Example 3 of the present invention.

[0044] Figure 4 The microcalorimetric diagram of the composite polymer current collector prepared in Example 3 of this invention;

[0045] Figure 5 A comparison chart showing the rate performance of sodium-ion capacitors assembled using the current collector provided in Example 3 and the current collector provided in Comparative Example 1;

[0046] Figure 6 A comparison chart of the energy density and power density of sodium-ion capacitors assembled using the current collector provided in Example 3 and the current collector provided in Comparative Example 1;

[0047] Figure 7 The diagram shows the cycle performance test results of a CR2032 type sodium-ion capacitor assembled using the current collector provided in Example 3.

[0048] Explanation of reference numerals in the attached figures:

[0049] 1. Polymer base film; 2. Metal layer. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Those skilled in the art should understand that the embodiments described are merely illustrative of the invention and should not be considered as specific limitations thereof. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention. Process parameters in the following embodiments that do not specify specific conditions are generally based on conventional conditions, unless otherwise specified, indicating that all raw materials are commercially available or commonly used in this industry.

[0051] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this invention.

[0052] In a first aspect, the present invention provides a composite polymer current collector. Figure 1 A schematic diagram of the composite polymer current collector provided by the present invention is shown below. Figure 1 As shown, the composite polymer current collector includes a polymer base film 1 and a metal layer 2 disposed on at least one surface of the polymer base film 1, wherein the material of the polymer base film 1 includes a polyarylether resin containing a diazanaphthone structure, and the polyarylether resin containing a diazanaphthone structure has the following chemical structure:

[0053]

[0054] Where n is a positive integer.

[0055] The composite polymer current collector provided by the present invention uses a polyarylene ether resin containing a diazanaphthone structure as a substrate and a metal layer is provided on the substrate. This results in a lower areal density of the current collector, thereby reducing the mass ratio of the current collector in the battery cell and improving the mass energy density of the sodium-based energy storage device. In addition, there is a strong bonding force between the metal layer and the polyarylene ether resin containing a diazanaphthone structure.

[0056] The composite polymer current collector provided by this invention has a small thickness, much smaller than that of commercial copper foil and aluminum foil (20μm), thereby reducing the volume of inactive materials in the energy storage device and significantly improving the volumetric energy density of the energy storage device from the device perspective.

[0057] Currently used electrolytes are typically highly flammable, posing serious safety hazards to battery cells. Traditional metal current collectors have limited functionality and cannot effectively prevent the spread of fire in the event of ignition or deflagration in sodium-based energy storage devices. Since polyarylether resins containing diazanaphthone structures possess intrinsic flame retardancy, achieving a V0 flame retardancy rating, the composite polymer current collector provided by this invention improves the safety of sodium-based energy storage devices by using polyarylether resins containing diazanaphthone structures as the substrate.

[0058] In the above-mentioned composite polymer current collector, as an optional embodiment, the material of the metal layer 2 includes at least one of aluminum and copper.

[0059] In the aforementioned composite polymer current collector, as an optional embodiment, the thickness of the polymer base film 1 is 1-15 μm, for example, it can be 1 μm, 3 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 11 μm, 13 μm, or 15 μm, preferably 5-9 μm. An excessively thick polymer base film will increase the overall mass of the composite current collector, while an excessively thin film will lead to poor structural stability.

[0060] In the aforementioned composite polymer current collector, as an optional embodiment, the thickness of the metal layer 2 is 100nm-2000nm, for example, it can be 100nm, 200nm, 400nm, 500nm, 600nm, 800nm, 1000nm, 1200nm, 1400nm, 1600nm, 1800nm, or 2000nm, preferably 800-1200nm. An excessively thick metal layer will significantly increase the mass of the composite current collector, while an excessively thin metal layer will result in poor conductivity of the current collector, failing to meet usage requirements.

[0061] In the above-mentioned composite polymer current collector, as an optional embodiment, the number average molecular weight of the polyarylether resin containing the diazanaphthone structure is 20,000-50,000 g / mol, for example, it can be 20,000 g / mol, 25,000 g / mol, 30,000 g / mol, 35,000 g / mol, 40,000 g / mol, 45,000 g / mol or 50,000 g / mol.

[0062] In a second aspect, the present invention provides a method for preparing a composite polymer current collector as described in the first aspect, the method comprising the following steps:

[0063] The metal layer 2 is formed on at least one surface of the polymer base film 1.

[0064] In the above-mentioned method for preparing the composite polymer current collector, as an optional embodiment, the preparation method does not include a pretreatment step aimed at increasing the surface energy of the polymer base film 1 before forming the metal layer 2. The polyarylene ether resin containing a diazanaphthone structure in this invention exhibits strong adhesion to the metal layer, eliminating the need for a pretreatment step to enhance the adhesion between the base film and the metal layer. The preparation method provided by this invention significantly reduces equipment and production costs, improves production efficiency, avoids potential thermal damage, mechanical damage, or chemical contamination to the polymer base film during the pretreatment process, and ensures the integrity of the base film and its inherent excellent properties.

[0065] In the above-mentioned method for preparing composite polymer current collectors, as an optional embodiment, the pretreatment step aimed at improving surface energy includes at least one of corona treatment, plasma treatment, and chemical etching treatment.

[0066] In the above-mentioned method for preparing the composite polymer current collector, as an optional embodiment, the method for preparing the polymer base film 1 includes the following steps:

[0067] S1. Preparation of polyarylene ether resin slurry containing a diazanaphthone structure:

[0068] Dissolve polyarylene ether resin powder containing a diazanaphthone structure in a polar solvent and stir until completely dissolved to obtain a polyarylene ether resin slurry containing a diazanaphthone structure.

[0069] S2, Film Formation:

[0070] The polyarylene ether resin slurry containing the diazanaphthone structure is subjected to film-forming treatment and post-treatment to obtain the polymer base film 1.

[0071] In the above-mentioned method for preparing composite polymer current collectors, as an optional embodiment, in step S1, the mass ratio of the polyarylether resin powder containing the diazanaphthone structure to the polar solvent is 1:5-15, for example, it can be 1:5, 1:6, 1:7, 1:9, 1:11, 1:13 or 1:15.

[0072] In the above-mentioned method for preparing composite polymer current collectors, as an optional embodiment, in step S1, the polar solvent includes one of N-methylpyrrolidone, N,N-dimethylacetamide, and chloroform.

[0073] In the above-mentioned method for preparing composite polymer current collectors, as an optional embodiment, in step S1, the stirring temperature is 80-120°C, for example, 80°C, 90°C, 100°C, 110°C or 120°C.

[0074] In the above-mentioned method for preparing composite polymer current collectors, as an optional embodiment, in step S2, the film-forming process includes: coating the slurry onto the surface of a substrate, drying it to evaporate the polar solvent, and forming a solid film, wherein the drying is performed using a gradient temperature rise method.

[0075] In the above-mentioned method for preparing composite polymer current collectors, as an optional embodiment, in step S2, the coating is performed by a blade coating method, and the gap between the bottom of the blade and the surface of the substrate is 25μm-500μm, for example, it can be 25μm, 50μm, 100μm, 150μm, 200μm, 250μm, 300μm, 350μm, 400μm, 450μm or 500μm.

[0076] In the above-mentioned method for preparing composite polymer current collectors, as an optional embodiment, the substrate includes a glass plate.

[0077] In the above-mentioned method for preparing composite polymer current collectors, as an optional embodiment, before coating the slurry onto the substrate surface, the film-forming process further includes: pre-treating the substrate, the pre-treatment including: sequentially cleaning the substrate surface with deionized water and ethanol, and then drying it at 50-120°C (e.g., 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, 110°C or 120°C) for 10-60 minutes (e.g., 10 minutes, 20 minutes, 30 minutes, 40 minutes, 50 minutes or 60 minutes).

[0078] In the above-mentioned method for preparing composite polymer current collectors, as an optional embodiment, in step S2, the gradient heating method includes first holding the temperature at 60-80°C (e.g., 60°C, 65°C, 70°C, 75°C, or 80°C) for 6-12 hours (e.g., 6h, 7h, 8h, 9h, 10h, 11h, or 12h), and then heating at 2-10°C / min (e.g., 2°C / min). The temperature is increased to 130-200°C (e.g., 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C, or 200°C) at a heating rate of n, 4°C / min, 6°C / min, 8°C / min, or 10°C / min, and held at that temperature for 12-24 hours (e.g., 12h, 14h, 16h, 18h, 20h, 22h, or 24h). By limiting the heating rate to 2-10°C / min, this invention ensures that the solvent escapes at a controllable and stable rate, avoiding internal defects (e.g., internal bubbles, pinholes, or even cracking) and stress cracking caused by excessively rapid surface drying, while maintaining reasonable production efficiency, thus achieving a balance between "quality" and "efficiency". By setting a specific low-temperature holding stage (60~80°C), the solvent can escape gently and uniformly, initially forming a stable film structure, laying the foundation for subsequent high-temperature processing. If the temperature is directly raised from room temperature to above 130°C, the film will form a "honeycomb" porous structure and a severely uneven surface. By setting a specific high-temperature holding stage (130~200°C), residual solvent is ensured to be completely removed, while promoting the relaxation and rearrangement of polymer molecular chains, effectively releasing internal stress, thereby obtaining a polymer-based film with extremely low solvent residue, excellent mechanical properties, dimensional stability, and high thermal stability.

[0079] In the above-mentioned method for preparing composite polymer current collectors, as an optional embodiment, in step S2, the post-processing includes: immersing a substrate with a solid film in water to detach the film from the substrate, and then drying it.

[0080] In the above-mentioned method for preparing composite polymer current collectors, as an optional embodiment, the metal layer 2 is formed by at least one of vapor deposition, magnetron sputtering, ion plating, and electroplating.

[0081] In the above-mentioned method for preparing composite polymer current collectors, as an optional embodiment, the magnetron sputtering is vacuum magnetron sputtering. Specific parameters of the magnetron sputtering include: the target material is either a copper target or an aluminum target; the base vacuum level is 0.00001-0.01 Pa (for example, it can be 0.00001 Pa, 0.0001 Pa, 0.001 Pa, 0.003 Pa, 0.005 Pa, 0.007 Pa, or 0.01 Pa); and the temperature of the magnetron sputtering chamber is 25~100 °C. °C (e.g., 25°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, or 100°C), sputtering atmosphere is either nitrogen or argon, working pressure is 0.3~10Pa (e.g., 0.3Pa, 1Pa, 3Pa, 5Pa, 7Pa, or 10Pa), sputtering time is 100~3000s (e.g., 100s, 500s, 1000s, 1...). The flow rate of nitrogen or argon during magnetron sputtering is 20-70 sccm (e.g., 20 sccm, 30 sccm, 40 sccm, 50 sccm, 60 sccm or 70 sccm), and the sputtering power is 20-250 W (e.g., 20 W, 50 W, 100 W, 150 W, 200 W or 250 W, preferably 150-200 W).

[0082] "Background vacuum" refers to the vacuum level achieved in the vacuum chamber before magnetron sputtering coating, when the chamber is evacuated but before the working gas (such as argon) is introduced and sputtering begins.

[0083] Sputtering time that is too long will result in an excessively thick coating with very little benefit to improving electronic conductivity, while sputtering time that is too short will result in a coating that fails to meet the requirements for electronic conductivity.

[0084] To achieve better sputtering results during magnetron sputtering, the sputtering chamber is heated. The resin used in this invention can complete the sputtering process at a higher temperature and maintain its structural stability even with increased chamber temperature. Ultimately, this results in a tighter bond between the resin matrix and the metal coating, leading to higher interfacial strength. If the temperature of the magnetron sputtering chamber is too high, metal atoms may diffuse too deeply into the base film, or the grains may become coarse, which is detrimental to obtaining the desired microstructure and conductivity. Conversely, if the temperature of the magnetron sputtering chamber is too low, the bonding force between the resin matrix and the metal coating will be weak.

[0085] Thirdly, the present invention provides an application of the composite polymer current collector as described in the first aspect or the composite polymer current collector prepared by the preparation method described in the second aspect in sodium-based energy storage devices, lithium-based energy storage devices or potassium-based energy storage devices.

[0086] In the above applications, as an optional implementation, the sodium-based energy storage device includes at least one of sodium-ion batteries, sodium-sulfur batteries, and sodium-ion capacitors.

[0087] In the above applications, as an optional implementation, the lithium-based energy storage device includes at least one of a lithium-ion battery, a lithium-sulfur battery, and a lithium-ion capacitor.

[0088] In the above applications, as an optional implementation, the potassium-based energy storage device includes at least one of a potassium-ion battery and a potassium-ion capacitor.

[0089] The present invention will now be described in further detail with reference to specific embodiments and comparative examples.

[0090] Example 1

[0091] This embodiment provides a method for preparing a composite polymer current collector, including the following steps:

[0092] S1, PPEK (M) polyarylene ether resin containing a diazanaphthone structure n The structure of (42000 g / mol) is as follows:

[0093] , where n is a positive integer;

[0094] Weigh 1 g of polyarylene ether resin powder containing diazanaphthone structure and add it to 9 g of N-methylpyrrolidone. Stir at 100°C for 6 h until the polyarylene ether resin is completely dissolved to obtain polyarylene ether resin slurry.

[0095] S2. Prepare a glass plate and clean its surface with deionized water and ethanol in sequence to ensure the glass plate is clean. Place the glass plate in a 90°C oven and dry for 20 min. Remove and set aside. Pour the slurry obtained in step S1 onto the left side of the glass plate and use a 100μm scraper (the gap between the bottom of the scraper and the surface of the glass plate is 100μm) to scrape it evenly from the left side to the right side of the glass plate, so that the polyarylene ether resin slurry is evenly spread on the glass plate. Transfer the glass plate into an 80°C oven and keep it at that temperature for 6 h. Then, increase the temperature to 180°C at a heating rate of 10°C / min and keep it at that temperature for 12 h to remove residual solvent. Remove the glass plate, let it cool to room temperature, and then soak it in deionized water for 30 min. Take out the film floating on the water surface and dry it to obtain a polyarylene ether resin film with a thickness of 6 μm.

[0096] S3. Cut the polyarylene ether resin film obtained in step S2 into a regular rectangle, fix it to a glass plate with polyimide tape, and place it in a magnetron sputtering instrument for vacuum magnetron sputtering with an aluminum target. The required background vacuum for magnetron sputtering is 0.003 Pa, the heating temperature (temperature of the magnetron sputtering chamber) is 40 °C, the sputtering atmosphere is argon, the argon flow rate is 30 sccm, the working pressure is 0.3 Pa, the sputtering time is 150 s, and the sputtering power is 150 W. After the sputtering program is completed, flip the film over and fix it to the glass plate, and repeat the above operation to perform vacuum magnetron sputtering on the other side of the film. After the program is completed, peel off the film to obtain the composite polymer current collector, with a single-sided aluminum coating thickness of 100 nm.

[0097] The composite polymer current collector prepared in this embodiment includes a polyarylene ether resin base film containing a diazanaphthone structure and an aluminum layer disposed on both sides of the base film.

[0098] Example 2

[0099] This embodiment provides a method for preparing a composite polymer current collector, including the following steps:

[0100] S1, PPEK (M) polyarylene ether resin containing a diazanaphthone structure n The structure of (42000 g / mol) is as follows:

[0101] , where n is a positive integer;

[0102] Weigh 1 g of polyarylene ether resin powder containing diazanaphthone structure and add it to 11 g of N-methylpyrrolidone. Stir at 100 °C for 6 h until the polyarylene ether resin is completely dissolved to obtain polyarylene ether resin slurry.

[0103] S2. Prepare a glass plate and clean its surface with deionized water and ethanol in sequence to ensure the glass plate is clean. Place the glass plate in a 70 °C oven and dry for 30 min. Remove and set aside. Pour the slurry obtained in step S1 onto the left side of the glass plate and use a 150 μm scraper to evenly spread it from the left side to the right side of the glass plate, so that the polyarylene ether resin slurry is evenly spread on the glass plate. Transfer the glass plate to an 80 °C oven and keep it at that temperature for 10 h. Then, increase the temperature to 200 °C at a heating rate of 5 °C / min and keep it at that temperature for 16 h to remove residual solvent. Remove the glass plate, let it cool to room temperature, and then soak it in deionized water for 30 min. Take out the film floating on the water surface and dry it to obtain a polyarylene ether resin film with a thickness of 7 μm.

[0104] S3. Cut the polyarylene ether resin film obtained in step S2 into a regular rectangle, fix it to a glass plate with polyimide tape, and place it in a magnetron sputtering instrument for vacuum magnetron sputtering with an aluminum target. The required background vacuum for magnetron sputtering is 0.003 Pa, the heating temperature is 40 °C, the sputtering atmosphere is argon, the argon flow rate is 30 sccm, the working pressure is 0.3 Pa, the sputtering time is 300 s, and the sputtering power is 150 W. After the sputtering program is completed, flip the film over and fix it to the glass plate, and repeat the above operation to perform vacuum magnetron sputtering on the other side of the film. After the program is completed, peel off the film to obtain the composite polymer current collector, with a single-sided aluminum coating thickness of 200 nm.

[0105] The composite polymer current collector prepared in this embodiment includes a polyarylene ether resin base film containing a diazanaphthone structure and an aluminum layer disposed on both sides of the base film.

[0106] Example 3

[0107] This embodiment provides a method for preparing a composite polymer current collector, including the following steps:

[0108] S1, PPEK (M) polyarylene ether resin containing a diazanaphthone structure n The structure of (42000 g / mol) is as follows:

[0109] , where n is a positive integer;

[0110] Weigh 1 g of polyarylene ether resin powder containing diazanaphthone structure and add it to 9 g of N-methylpyrrolidone. Stir at 100°C for 6 h until the polyarylene ether resin is completely dissolved to obtain polyarylene ether resin slurry.

[0111] S2. Prepare a glass plate and clean its surface sequentially with deionized water and ethanol to ensure the glass plate surface is clean. Place the glass plate in a 60 °C oven and dry for 30 min, then remove and set aside. Pour the slurry obtained in step S1 onto the left side of the glass plate and use a 100 μm (the gap between the bottom of the scraper and the surface of the substrate is 100 μm) scraper to uniformly spread the polyarylene ether resin slurry from the left side of the glass plate to the right side, so that the polyarylene ether resin slurry is evenly spread on the glass plate. Transfer the glass plate into an 80 °C oven and keep it at that temperature for 6 h, then raise the temperature to 180 °C at a heating rate of 10 °C / min and keep it at that temperature for 12 h to remove residual solvent. Remove the glass plate, let it cool to room temperature, and then soak it in deionized water for 30 min. Take out the film floating on the water surface and dry it to obtain a polyarylene ether resin film with a thickness of 6 μm.

[0112] S3: Cut the polyarylene ether resin film obtained in step S2 into a regular rectangle, fix it to a glass plate with polyimide tape, and place it in a magnetron sputtering instrument for vacuum magnetron sputtering with an aluminum target; wherein, the required background vacuum degree for magnetron sputtering is 0.003 Pa, the heating temperature (temperature of the magnetron sputtering chamber) is 40 °C, the sputtering atmosphere is argon, the argon flow rate is 30 sccm, the working pressure is 0.3 Pa, the sputtering time is 600 s, and the sputtering power is 180 W; after the sputtering program is completed, flip the film over and fix it to the glass plate, and repeat the above operation to perform vacuum magnetron sputtering on the other side of the film; after the program is completed, peel off the film to obtain the composite polymer current collector, with a single-sided aluminum coating thickness of 500 nm.

[0113] The composite polymer current collector prepared in this embodiment includes a polyarylene ether resin base film containing a diazanaphthone structure and an aluminum layer disposed on both sides of the base film.

[0114] The tensile properties of the composite polymer current collector and the polyarylether resin film prepared in this embodiment were tested using a universal testing machine. The results are as follows: Figure 2 As shown, Figure 2 This is a comparison chart of the tensile properties of the composite polymer current collector and the polyaryl ether resin film prepared in this embodiment. Figure 2 It is known that the tensile strength of pure polymer resin is 82 MPa, and after sputtering aluminum coating, the tensile strength can reach 130 MPa, exhibiting excellent mechanical properties.

[0115] Figure 3 The SEM image (left) and EDS spectrum (right) of the composite polymer current collector prepared in this embodiment are obtained from... Figure 3 It can be seen that the thickness of the composite polymer current collector is only 7μm, the aluminum coating thickness on one side is about 500nm, the film is dense and flat, and the EDS energy spectrum shows that the Al coating is evenly distributed on both sides, while the middle is polyarylether resin.

[0116] The fire safety performance of the composite polymer current collector prepared in this embodiment was tested using a micro calorimeter (MCC). Specifically, the composite polymer current collector prepared in this embodiment was placed inside the MCC, and its fire safety performance was determined by the obtained heat release rate. The results are as follows: Figure 4 As shown, Figure 4 The microcalorimetric map of the composite polymer current collector prepared in this embodiment is obtained from... Figure 4 It can be seen that the composite polymer current collector has intrinsic flame retardant properties, with a flame retardant rating of V0.

[0117] Example 4

[0118] The preparation method of the composite polymer current collector provided in this embodiment is basically the same as that in embodiment 3. The difference is that in step S3, a copper target is used for vacuum magnetron sputtering, the heating temperature is 80°C, the sputtering atmosphere is nitrogen, the working pressure is 3Pa, the sputtering time is 700s, the sputtering power is 100W, and the thickness of the single-sided copper plating layer is 500nm.

[0119] Comparative Example 1

[0120] The current collector provided in this comparative example is a commercial aluminum foil current collector with a thickness of 15μm.

[0121] Comparative Example 2

[0122] The current collector provided in this comparative example is a commercial copper foil current collector with a thickness of 22μm.

[0123] Comparative Example 3

[0124] The preparation method of the composite polymer current collector provided in this comparative example is basically the same as that in Example 3, except that the polyarylether resin containing the diazanaphthone structure is replaced with a polyarylether resin without the diazanaphthone structure (M). n =41000g / mol), the structure is as follows:

[0125] , where n is a positive integer.

[0126] Performance testing

[0127] 1. Electronic conductivity and areal density testing

[0128] The electronic conductivity of the composite polymer current collectors, commercial copper foil, and commercial aluminum foil prepared in Examples 1-4 and Comparative Example 3 was tested using a four-probe conductivity meter.

[0129] Weigh the composite polymer current collectors, commercial copper foil, and commercial aluminum foil prepared in Examples 1-4 and Comparative Example 3, and calculate their areal densities.

[0130] The results are shown in Table 1.

[0131] Table 1

[0132]

[0133] As shown in Table 1, the electronic conductivity of the composite polymer current collector prepared in the examples is not significantly different from that of Comparative Example 1 (commercial aluminum foil, Al CC) and Comparative Example 2 (commercial copper foil, Cu CC), and is within the same order of magnitude. The areal density of the examples is much lower than that of Comparative Example 1 (4.25 mg·cm³). -2 And 8.4 mg·cm² in Comparative Example 2 -2Comparing Example 3 with Comparative Example 3, the electronic conductivity of the current collector provided by Comparative Example 3 is poor because the polyarylether resin without the diazanaphthone structure has poor adhesion to the metal coating.

[0134] 2. Resin-metal lap shear strength test

[0135] The inherent adhesion of polyarylether resin to metal was evaluated using an overlap shear strength test. The specific steps are as follows:

[0136] The polyarylene ether resin powder containing the diazanaphthone structure in Example 3 and the polyarylene ether resin powder without the diazanaphthone structure in Comparative Example 3 were weighed separately and placed between the overlapping areas of two aluminum plates. They were then hot-pressed using a hot press, followed by pressure holding and cooling to prepare standard lap shear specimens. The shear strength of the specimens was tested using a universal testing machine at a tensile rate of 1.5 mm / min. The results are shown in Table 2.

[0137] Table 2

[0138]

[0139] As shown in Table 2, compared with Comparative Example 3, the interfacial bonding strength between the polyarylene ether resin containing the diazanaphthone structure and aluminum in Example 3 is higher, indicating that the bonding force between the base film and the metal layer in the composite polymer current collector prepared by the present invention is stronger.

[0140] 3. Electrochemical performance testing

[0141] Commercially available YP-80F activated carbon positive electrode powder, conductive agent Super P, and binder PVDF-900 were mixed in a mass ratio of 7:2:1. A certain amount of N-methylpyrrolidone was added, and the mixture was stirred evenly to obtain a positive electrode slurry. The positive electrode slurry was coated onto the current collectors provided in the examples and comparative examples, respectively. After drying, rolling, and slitting, positive electrode sheets were obtained. A sodium sheet was used as the negative electrode, and a 1M NaClO4 solution with EC and DEC as the solvent was used as the test electrolyte. A CR2032 button sodium-ion capacitor was assembled in an argon-filled glove box.

[0142] The rate performance of the CR2032 button-type sodium-ion capacitor was tested using the LAND testing system: the sodium-ion capacitor was subjected to constant current charge-discharge tests at current densities of 0.1 A / g, 0.2 A / g, 0.5 A / g, 1 A / g, 2 A / g, and 5 A / g, respectively. The results are shown in [Figure number missing]. Figure 5 , Figure 5 This is a comparison chart of the rate performance of sodium-ion capacitors assembled using the current collector provided in Example 3 and the current collector provided in Comparative Example 1. Figure 5 As can be seen, the rate performance of Example 3 based on the entire electrode mass is much higher than that of Comparative Example 1. Example 3 at 0.1, 0.2, 0.5, 1, 2 and 5 A·g-1 At different current densities, their discharge specific capacities can reach 35, 33, 31, 28, 25 and 14 mAh·g, respectively. -1 This indicates that the composite polymer current collector provided by the present invention is lighter than that of conventional metal current collectors.

[0143] The energy density and power density of the CR2032 button-type sodium-ion capacitor were tested using the LAND test system, and the results are as follows: Figure 6 As shown, Figure 6 This is a comparison chart of the energy density and power density of sodium-ion capacitors assembled using the current collectors provided in Example 3 and Comparative Example 1. Figure 6 As can be seen, the energy density based on the entire electrode mass in Example 3 can reach a maximum of 100 Wh·kg. -1 It is much higher than the comparative example of 29Wh·kg -1 This indicates that the current collector provided by the present invention can significantly improve the energy density of energy storage devices.

[0144] The cycling performance of the CR2032 button sodium-ion capacitor was tested using the LAND test system, and the results are as follows: Figure 7 As shown, Figure 7 The circuit performance test diagram shows the CR2032 type sodium-ion capacitor assembled using the current collector provided in Example 3. The discharge specific capacity is the discharge specific capacity based on the mass of the active material. Figure 7 It can be seen that in Example 3, at 5A·g -1 After 15,000 cycles at current density, the capacity retention rate is 100%.

[0145] The multifunctional composite polymer current collector prepared by this invention introduces a lightweight flame-retardant polymer into the current collector, which not only significantly reduces the mass ratio of the current collector in the battery cell while ensuring electronic transmission and mechanical properties, but also endows the composite current collector with intrinsic flame-retardant properties, ultimately realizing a sodium-based energy storage device with high energy density and high safety.

[0146] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A composite polymer current collector, characterized in that, The composite polymer current collector includes a polymer base film (1) and a metal layer (2) disposed on at least one surface of the polymer base film (1), wherein the material of the polymer base film (1) includes a polyarylene ether resin containing a diazanaphthone structure, and the polyarylene ether resin containing a diazanaphthone structure has the following chemical structure: Where n is a positive integer.

2. The composite polymer current collector according to claim 1, characterized in that, The material of the metal layer (2) includes at least one of aluminum and copper.

3. The composite polymer current collector according to claim 1, characterized in that, The thickness of the polymer base film (1) is 1-15 μm; And / or, the thickness of the metal layer (2) is 100nm-2000nm; And / or, the number average molecular weight of the polyarylether resin containing the diazanaphthone structure is 20,000-50,000 g / mol.

4. A method for preparing a composite polymer current collector as described in any one of claims 1-3, characterized in that, The preparation method includes the following steps: The metal layer (2) is formed on at least one side surface of the polymer base film (1).

5. The method for preparing the composite polymer current collector according to claim 4, characterized in that, Before forming the metal layer (2), the preparation method does not include a pretreatment step aimed at improving the surface energy of the polymer base film (1); And / or, the metal layer (2) is formed by at least one of vapor deposition, magnetron sputtering, ion plating, and electroplating.

6. The method for preparing the composite polymer current collector according to claim 4, characterized in that, The preparation method of the polymer-based film (1) includes the following steps: S1. Preparation of polyarylene ether resin slurry containing a diazanaphthone structure: Dissolve polyarylene ether resin powder containing a diazanaphthone structure in a polar solvent and stir until completely dissolved to obtain a polyarylene ether resin slurry containing a diazanaphthone structure. S2, Film Formation: The polyarylene ether resin slurry containing the diazanaphthone structure is subjected to film-forming treatment and post-treatment to obtain the polymer base film (1).

7. The method for preparing the composite polymer current collector according to claim 6, characterized in that, In step S1, the mass ratio of the polyarylene ether resin powder containing the diazanaphthone structure to the polar solvent is 1:5-15; And / or, in step S1, the polar solvent includes one of N-methylpyrrolidone, N,N-dimethylacetamide, and chloroform; And / or, in step S1, the stirring temperature is 80-120°C; And / or, in step S2, the film-forming process includes: coating the slurry onto the substrate surface, drying to evaporate the polar solvent, and forming a solid film, wherein the drying is performed using a gradient temperature method; And / or, in step S2, the post-processing includes: immersing the substrate with the solid film in water to detach the film from the substrate, followed by drying.

8. The method for preparing the composite polymer current collector according to claim 7, characterized in that, In step S2, the coating is performed using a blade coating method, and the gap between the bottom of the blade and the surface of the substrate is 25μm-500μm; And / or, the substrate includes a glass plate; And / or, before coating the slurry onto the substrate surface, the film-forming process further includes: pre-treating the substrate, the pre-treating process including: sequentially cleaning the substrate surface with deionized water and ethanol, and then drying it at 50-120°C for 10-60 minutes; And / or, in step S2, the gradient heating method includes first holding at 60-80°C for 6-12 hours, then heating to 130-200°C at a heating rate of 2-10°C / min and holding for 12-24 hours.

9. The method for preparing the composite polymer current collector according to claim 5, characterized in that, The magnetron sputtering is vacuum magnetron sputtering. The specific parameters of the magnetron sputtering include: the target material is either a copper target or an aluminum target; the background vacuum is 0.00001-0.01 Pa; the temperature of the magnetron sputtering chamber is 25-100 °C; the sputtering atmosphere is either nitrogen or argon; the working pressure is 0.3-10 Pa; the sputtering time is 100-3000 s; the flow rate of nitrogen or argon during magnetron sputtering is 20-70 sccm; and the sputtering power is 20-250 W.

10. The application of a composite polymer current collector as described in any one of claims 1-3 or a composite polymer current collector prepared by the preparation method described in any one of claims 4-9 in a sodium-based energy storage device, a lithium-based energy storage device or a potassium-based energy storage device.

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