A method for preparing a polyethylene-based metal carbonaceous current collector and applications thereof

Abstract

The application discloses a preparation method of a polyethylene metal carbonaceous current collector applied to an aluminum ion battery and an aluminum ion battery prepared by the method. The current collector preparation method is based on polyethylene only, carbon nanoparticles such as Ketjen black, acetylene black and Super P and metal powders such as micron-sized Mo and Ta are used as conductive bus bars, and through simple processes such as dry ball milling and hot pressing, the electrode has a high-efficiency conductive network, adhesion strength and electrochemical stability, so that the energy density and cycle life of the aluminum ion battery are improved. The light-weight and low-cost polyethylene metal carbonaceous current collector prepared by the preparation method has important significance for the development of high-energy and high-stability aluminum ion batteries and is expected to realize commercial production in the aluminum ion battery system.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical energy storage materials, and particularly relates to a method for preparing a polyethylene-based metal carbon current collector and its application in aluminum-ion batteries. Background Technology

[0002] Currently, aluminum-ion batteries commonly use highly acidic ionic liquid electrolytes (AlCl3 / [EMIm]Cl). To prevent corrosion from these highly acidic electrolytes, aluminum-ion batteries often use acid-resistant materials as current collectors, such as molybdenum (≈10.23g cm⁻¹). -3 ), Tantalum (≈16.65 g cm) -3 ) and tungsten (≈19.34 g cm) -3 However, the inherent high density and smooth surface of these materials often lead to an excessively high proportion of inactive components in the positive electrode and weak interfacial adhesion strength, thus significantly reducing the overall energy density of the electrode and the cycle life of the battery. For other alternative metal current collectors, such as stainless steel foil (≈7.93 g cm⁻¹),... -3 ), titanium foil (≈4.5 g cm) -3 ), nickel foil (≈8.9 g cm) -3 ) and chrome foil (≈7.19 g cm -3 Although the aforementioned metal current collectors have low density, their voltage window is narrow (below 2.0 V vs. Al). 3+ AlCl4, therefore, requires further chemical modification to improve its electrochemical stability in order to adapt to a wider operating voltage range. Furthermore, in aluminum-ion batteries (AIBs), large-size AlCl4... - The insertion of ions easily causes electrode volume expansion, significantly reducing the adhesion between the electrode material and the current collector, leading to the separation of the electrode material from the current collector. Furthermore, exploratory research has been conducted on the development of non-graphite carbon-based current collectors, primarily aiming to avoid the ion insertion problem during electrochemical processes. However, the prevalent sp... 3 with sp 2 Hybridized orbitals and mixed phases reduce intrinsic conductivity, limiting their large-scale application in practical battery systems. Therefore, to meet the diverse requirements of aluminum-ion batteries for current collectors, there is an urgent need to provide a novel lightweight current collector that combines good conductivity with electrochemical stability. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention proposes a method for preparing a polyethylene-based carbon metal current collector for aluminum-ion batteries. The polyethylene-based carbon metal current collector obtained by this method can significantly improve the energy density and cycle life of aluminum-ion batteries. The method proposed in this invention simply uses polyethylene (PE) as a base and carbon nanoparticles (CBs) and micron-sized metal powders as conductive wires. Through simple processes such as dry ball milling and hot pressing, the electrode acquires a highly efficient conductive network, high adhesion strength, and strong electrochemical stability, thereby improving the energy density and cycle life of aluminum-ion batteries. The lightweight and low-cost polyethylene-based carbon metal current collector obtained by the method of this invention is of great significance for the development of high-specific-energy, high-stability aluminum-ion batteries (AIBs).

[0004] In a first aspect, the present invention discloses a method for preparing a polyethylene-based metal carbon current collector, comprising the following steps: S1. Weighing According to the required proportions of materials, accurately weigh polyethylene (PE), carbon nanoparticles (CBs), and micron-sized metal powder (Met). S2. Ball mill The weighed carbon nanoparticles and micron-sized metal powders were dry ball-milled under a high-purity argon atmosphere to promote thorough mixing of the raw materials through mechanical force. S3. Secondary ball milling Weighed polyethylene was added to the mixture of carbon nanoparticles and micron-sized metal powders, and dry ball milling was carried out under the protection of high-purity argon atmosphere. Mechanical force was used to promote full mixing between the raw materials, and the powder sample was collected after completion. S4. Hot pressing After the powder sample is evenly spread on the surface of the stainless steel foil, the stainless steel foil is sandwiched on the other side of the powder sample to form a stainless steel clip with the powder sample sandwiched in the middle. The stainless steel clip is then hot-pressed to make the powder sample in the stainless steel clip form a dense film. S5. Sampling After the stainless steel clips have cooled, the PE-CBs-Met material is removed from the stainless steel clips to obtain the polyethylene-based metal carbon current collector.

[0005] Furthermore, in step S1, the ratio of PE, CBs, and Met is 5~6:2~3:1~2.

[0006] Furthermore, the carbon nanoparticles are selected from any one or a combination of Ketjen Black (KBC), acetylene black (AB), and Super P (SP).

[0007] Furthermore, the micron-sized metal powder is selected from micron-sized molybdenum (Mo) powder and / or micron-sized tantalum (Ta) powder.

[0008] Furthermore, in step S2, the ball mill rotation speed of the dry ball mill is 200~300 rpm, the ball milling time is 12~48h, the diameter of the ball milling ball is 3~8mm, and the ball-to-material ratio is 20~30:1.

[0009] Furthermore, in step S3, the ball mill rotation speed of the dry ball mill is 300~400 rpm, the ball milling time is 6~12 h, the diameter of the ball milling ball is 3~8 mm, and the ball-to-material ratio is 20~30:1.

[0010] Furthermore, before hot pressing in step S4, the powder sample is vacuum dried to remove moisture. The drying temperature is 60~80℃ and the drying time is 12~24h.

[0011] Furthermore, in step S4, the hot pressing pressure is 18~25MPa, the hot pressing holding time is 15~20 minutes, and the hot pressing temperature is 125~150℃.

[0012] Furthermore, after hot pressing in step S4, if the film thickness in the stainless steel clip is greater than the target thickness, further hot rolling is performed. The hot rolling temperature is not less than the melting temperature of polyethylene until the film thickness in the stainless steel clip reaches the target thickness. Then, the hot rolling is stopped, and after cooling, a polyethylene-based metal carbon current collector is obtained.

[0013] Secondly, the present invention also discloses an aluminum-ion battery system, comprising a current collector, a positive electrode material, a negative electrode material, and an electrolyte, wherein the current collector is prepared by the method for preparing a polyethylene-based metal carbon current collector according to the first aspect of the present invention.

[0014] Furthermore, the negative electrode material is an aluminum sheet, the positive electrode material includes graphite powder, Ketjen black, and carboxymethyl cellulose, and the electrolyte is a non-aqueous electrolyte, which is an ionic liquid containing aluminum chloride and [EMIm]Cl (1-ethyl-3-methylimidazolium chloride), wherein the molar ratio of aluminum chloride to [EMIm]Cl is 1:1.3~1.5.

[0015] This invention provides a method for preparing a polyethylene-based carbon metal current collector for aluminum-ion batteries. This method uses polyethylene as a base and carbon nanoparticles and micron-sized metal powders as conductive wires. The polyethylene-based carbon metal current collector is prepared through simple dry ball milling and hot pressing, resulting in an electrode with a highly efficient conductive network, high adhesion strength, and strong electrochemical stability. The density of the PE-KBC-Mo current collector with a thickness of 90 μm obtained by this method is approximately 1.31 g / cm³. -3 This is equivalent to the density of the most commonly used 90μm thick molybdenum current collector (approximately 8.96 g cm⁻¹). -3The PE-KBC-Mo current collector, with a mass ratio of 14.62%, significantly reduces the mass ratio of the electrochemically inactive current collector in the positive electrode, thereby substantially improving the energy density of the aluminum-ion battery. Furthermore, the PE-KBC-Mo current collector exhibits high surface roughness, supporting interfacial mechanical interlocking. Simultaneously, the flexible polyethylene substrate effectively accommodates large-size AlCl4 cells. - and Al2Cl7 - The volume changes and lattice stresses caused by repeated insertion / extraction in the cathode material suppress fatigue damage to the electrode structure, thereby significantly improving the cycle life and safety performance of aluminum batteries. The lightweight, low-cost polyethylene-based carbonaceous current collector obtained by the method of this invention has extremely high value for the development of high-energy, high-stability aluminum-ion batteries and is expected to achieve commercial production in aluminum-ion battery systems. Compared with existing technologies, this invention has at least the following beneficial effects: (1) The preparation method of the present invention is based on polyethylene and uses carbon nanoparticles and micron-sized metal powder as conductive busbars, and the raw material cost is low.

[0016] (2) The preparation method of the present invention is only a simple dry ball milling and hot pressing. The ball milling and hot pressing processes are mature, with small and controllable errors, and can realize the large-scale production of new lightweight current collectors.

[0017] (3) The current collector obtained by the preparation method of the present invention has high adhesion strength between the interface and the active material, and is not easy to fall off. The flexible substrate effectively alleviates the volume change and lattice stress of the cathode material, which can significantly improve the cycle life of aluminum-ion batteries.

[0018] (4) The current collector obtained by the preparation method of the present invention has a low density. The density of the PE-KBC-Mo current collector is only about 14.62% of that of the molybdenum current collector, which greatly reduces the mass ratio of the electrochemically inactive current collector of the positive electrode and significantly improves the energy density of the aluminum ion battery.

[0019] (5) The current collector obtained by the preparation method of this application has a wide voltage window and is resistant to corrosion by highly acidic ionic liquid electrolyte (AlCl3 / [EMIm]Cl). Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the PE-KBC-Mo current collector used in this invention to enhance interfacial adhesion and alleviate interlayer stress in the cathode material. Figure 2 The XRD pattern of the PE-KBC-Mo current collector of this invention; Figure 3 The image shows the microstructure of the PE-KBC-Mo current collector characterized by an optical microscope. Figure 3 (Left) is a microstructure diagram at the 500μm scale. Figure 3 (Right) is a microstructure diagram at the 100μm scale; Figure 4 The image shows the microstructure of the PE-KBC-Mo current collector characterized by SEM. Figure 4 (Left) is a microstructure diagram at the 500μm scale. Figure 4 (Right) is a microstructure diagram at the 100μm scale; Figure 5 The image shows the EDS spectrum of the PE-KBC-Mo current collector of this invention, wherein... Figure 5 (Top left) is an EDS layered image. Figure 5 (Top right) is the total surface energy spectrum. Figure 5 (Bottom left) is the C-element EDS image. Figure 5 (Bottom right) is the EDS image of the Mo element; Figure 6 The image shows the surface microstructure of the PE-KBC-Mo current collector characterized by AFM. Figure 7 This is a cyclic voltammetry curve of the PE-KBC-Mo current collector aluminum-ion battery of the present invention; Figure 8 This is a charge-discharge curve of the PE-KBC-Mo current collector aluminum-ion battery of the present invention; Figure 9 This is the electrochemical impedance spectroscopy of the PE-KBC-Mo current collector aluminum-ion battery of the present invention; Figure 10 This is a linear sweep voltammetry curve of the PE-KBC-Mo current collector aluminum-ion battery of the present invention; Figure 11 This is a Tafel curve of the PE-KBC-Mo current collector aluminum-ion battery of the present invention; Figure 12 This is a test diagram of the cycle stability of the PE-KBC-Mo current collector aluminum-ion battery of the present invention.

[0022] Explanation of reference numerals in the attached figures: 1. Current collector; 2. Initial contact with cathode material slurry; 3. Cathode material slurry after coating; 4. Interlayer stress of cathode material. Detailed Implementation

[0023] The technical solution of this application will be clearly and completely described below with reference to the embodiments of this application. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0024] Unless otherwise specified, all temperatures mentioned herein are in degrees Celsius, and the preferred embodiments can be freely combined as needed. Those skilled in the art will understand that the data and parameters described in the examples are merely exemplary and do not constitute a limitation of the invention. All components used in the following examples and comparative examples are compounds known in the art, and all equipment used is equipment publicly known in the art. All components and equipment used in this invention can be obtained commercially or prepared using known techniques.

[0025] This invention provides a method for preparing a polyethylene-based metal carbon current collector, comprising the following steps: S1. Weighing According to the required proportions of the materials, accurately weigh out polyethylene, carbon nanoparticles, and micron-sized metal powder; S2. Ball mill The weighed carbon nanoparticles and micron-sized metal powders were dry ball-milled under a high-purity argon atmosphere to promote thorough mixing of the raw materials through mechanical force. S3. Secondary ball milling Weighed polyethylene was added to the mixture of carbon nanoparticles and micron-sized metal powders, and dry ball milling was carried out under the protection of high-purity argon atmosphere. Mechanical force was used to promote full mixing between the raw materials, and the powder sample was collected after completion. S4. Hot pressing After spreading the powder sample evenly on the surface of the stainless steel foil using a spatula or scraper, the stainless steel foil is sandwiched on the other side of the powder sample to form a stainless steel clip with the powder sample sandwiched in the middle. The stainless steel clip is then hot-pressed to form a dense film of the powder sample in the stainless steel clip. S5. Sampling After the stainless steel clips have cooled to room temperature, the PE-CBs-Met composite material is removed from the stainless steel clips, thus obtaining the polyethylene-based metal carbon current collector.

[0026] Preferably, the ratio of PE, CBs, and Met weighed in step S1 is 5~6:2~3:1~2.

[0027] Preferably, the carbon nanoparticles are selected from any one or a combination of Ketjen Black, acetylene black, and Super P.

[0028] Preferably, the micron-sized metal powder is selected from micron-sized molybdenum powder and / or micron-sized tantalum powder.

[0029] Preferably, in step S2, the dry ball milling can use a conventional high-energy planetary ball mill with a ball mill speed of 200~300 rpm, more preferably 300 rpm; the ball milling time depends on the specific ratio and powder quality, and the typical ball milling time is 12~48h; the diameter of the ball milling ball is 3~8mm; and the ball-to-material ratio is 20~30:1, more preferably 30:1.

[0030] Preferably, in step S3, the dry ball milling can use a conventional high-energy planetary ball mill with a ball mill speed of 300~400 rpm, more preferably 400 rpm; the ball milling time depends on the specific ratio and powder quality, and the typical ball milling time is 6~12 hours; the diameter of the milling balls is 3~8 mm; and the ball-to-material ratio is 20~30:1, more preferably 30:1.

[0031] Preferably, before hot pressing in step S4, the powder sample is vacuum dried to remove moisture, thereby ensuring the purity of the powder sample. The drying temperature is typically 60~80℃, preferably 60℃. The drying time is determined by completely removing moisture from the sample powder, typically 12~24 hours.

[0032] Preferably, in step S4, the hot pressing pressure is 18-25 MPa, the hot pressing holding time is 15-20 minutes, and the hot pressing temperature is 125-150°C. To ensure the powder sample in the stainless steel clip reaches this hot pressing temperature, a flat vulcanizing apparatus can be used to heat the powder sample in the stainless steel clip, setting the heating temperature to the hot pressing temperature. Once the powder sample reaches the hot pressing temperature, the subsequent hot pressing process can begin. The hot pressing process can be performed in a hot press commonly used in the art, such as an SPS device or a vacuum hot pressing device with controllable temperature and pressure. Through hot pressing, the powder sample in the stainless steel clip forms a dense, non-porous film.

[0033] After hot pressing in step S4, if the film thickness in the stainless steel clip is large, further hot calendering can be performed to improve its longitudinal electronic conductivity. To simplify the process, the hot calendering strength can be maintained at the original hot pressing strength, and the hot calendering temperature should not be lower than the polyethylene melting temperature, thus ensuring that the polyethylene melts and deformation can be observed. For example, a hot calendering temperature of 120°C can be selected. There is no specific requirement for the hot calendering holding time, such as 10-15 minutes, until the film thickness reaches the required thickness, at which point the hot calendering process can be stopped. The film thickness can be selected as 90 μm. Of course, if one hot calendering process fails to reduce the film thickness to the required thickness, multiple hot calendering processes can be performed, or the holding time of the hot calendering process can be directly extended until the film thickness reaches the required thickness.

[0034] To ensure the stainless steel clips are centered between the upper and lower pressure plates of the hot press, thus achieving uniform stress, the stainless steel clips can be placed on a 0.5cm thick silicon wafer. The stacked stainless steel clips and silicon wafers are then placed between the pressure plates of the hot press. The upper and lower pressure plates are closed, thus completing the hot pressing process at the set heating temperature for a certain holding time, followed by optional hot rolling. After the stainless steel clips cool to room temperature, the pressure is released, the hot press furnace door is opened, and the stainless steel clips are removed using crucible tongs. After removing the stainless steel clips, the upper layer of stainless steel foil is first peeled off, and then the individual PE-CBs-Met current collector is slowly removed.

[0035] The present invention also provides an aluminum-ion battery system, comprising a current collector, a positive electrode material, a negative electrode material and an electrolyte, wherein the current collector is prepared by the above-described method for preparing a polyethylene-based metal carbon current collector.

[0036] Preferably, the negative electrode material is an aluminum sheet, the positive electrode material includes graphite powder, Ketjen black, and polyvinylidene fluoride, and the electrolyte is a non-aqueous electrolyte. More preferably, the non-aqueous electrolyte is an ionic liquid containing aluminum chloride and [EMIm]Cl, wherein the molar ratio of aluminum chloride to [EMIm]Cl is 1:1.3~1.5.

[0037] The present invention will now be described in more detail with reference to exemplary embodiments. The following examples or experimental data are intended to illustrate the present invention, and those skilled in the art should understand that the present invention is not limited to these examples or experimental data. The raw materials used in the examples and comparative examples are all commercially available, as detailed below: Polyethylene (PE): Adamas, high molecular weight polyethylene powder with an average particle size of 125 μm; Ketjen Black (KBC): Kroeder, particle size 30~40nm; Acetylene black (AB): KELOD, particle size 30~40nm; Super P (SP): KELOD, with a particle size of 30~40nm; Molybdenum powder (Mo): Aladdin, average particle size ≤10μm; Tantalum powder (Ta): Aladdin, purity ≥99.9%, average particle size ≤44μm; Aluminum sheet (Al): ThermoFisher, purity ≥99.99%; Graphite powder (C): Aladdin; Carboxymethyl cellulose (CMC): Aladdin; Aluminum chloride (AlCl3): ThermoFisher; 1-Ethyl-3-methylimidazolium chloride ([EMIm]Cl): CJC.

[0038] Example 1 A PE-KBC-Mo current collector, the preparation method of which is a polyethylene-based metal carbon current collector includes the following steps: S1. Weighing According to the required proportions of materials, accurately weigh 3.0g of polyethylene, 1.0g of Ketjen Black, and 1.0g of micronized molybdenum powder. The mass ratio of PE, KBC, and Mo is 6:2:2. S2. Ball mill The weighed KBC and Mo powders were dry ball-milled for 24 hours under a high-purity argon atmosphere. The ball mill speed was 300 rpm, the ball diameter was 3~8 mm, and the ball-to-material ratio was 30:1. S3. Secondary ball milling Add the weighed PE to the KBC and Mo powder mixture, and continue dry ball milling for 6 hours under a high-purity argon atmosphere. The ball mill speed is 400 rpm, the ball diameter is 3~8 mm, and the ball-to-material ratio is 30:1. Collect the powder sample after ball milling. S4. Hot pressing After the powder sample is evenly spread on the surface of the stainless steel foil, the stainless steel foil is sandwiched on the other side of the powder sample to form a stainless steel clip with the powder sample sandwiched in the middle. The stainless steel clip is heated to 150°C and then hot-pressed at this temperature. The hot-pressing pressure is 20MPa and the hot-pressing holding time is 15 minutes, thereby forming a dense, non-porous film. Then, the film was hot-calendered at 120°C with a calendering pressure of 20 MPa and a holding time of 5 minutes to obtain a film with a thickness of 90 μm. S5. Sampling After the stainless steel clips have cooled to room temperature, remove the PE-KBC-Mo current collector from the stainless steel clips.

[0039] Figure 1 This is a schematic diagram of the PE-KBC-Mo current collector used in this invention to enhance interfacial adhesion and alleviate interlayer stress in the cathode material. Figure 1 As shown, the PE-KBC-Mo current collector 1 uses polyethylene as the matrix, and Ketjen Black and micron-sized molybdenum powder are uniformly dispersed in the polyethylene matrix. Figure 1 The structure composed of large white spheres represents polyethylene polymer, while the small black spheres represent mixed particles of Ketjen black and micron-sized molybdenum powder. Figure 1The illustration shows that after two ball milling processes, the KBC and Mo mixed particles are uniformly coated on the surface of the PE polymer, thereby achieving a uniform distribution of KBC and Mo within the PE matrix after hot pressing, forming a three-dimensional conductive network. The uniform roughness of the PE-KBC-Mo current collector surface significantly enhances its adhesion strength to the cathode material slurry, making the cathode material less prone to detachment, and the flexible substrate effectively alleviates the volume change and lattice stress of the cathode material.

[0040] XRD analysis of the PE-KBC-Mo current collector yielded the following results: Figure 2 As shown, elemental Mo is distributed in the PE-KBC-Mo current collector. The results of optical microscopy observation of the PE-KBC-Mo current collector sample are as follows. Figure 3 As shown, distinct block boundary morphology can be observed in the PE-KBC-Mo current collector. SEM tests were performed on the PE-KBC-Mo current collector, and the results are as follows. Figure 4 As shown, a clear block boundary morphology can also be observed. KBC constructs a continuous conductive network on the polyethylene surface, enhancing the electronic conductivity of the current collector. EDS analysis of the PE-KBC-Mo current collector yielded the following results: Figure 5 As shown, the red K-line represents carbon (C) and the green L-line represents molybdenum (Mo). It is evident that C and Mo are uniformly dispersed and mixed, indicating that micron-sized molybdenum powder is uniformly distributed within the polyethylene matrix. This achieves a synergistic improvement in the electronic conductivity and mechanical properties of the current collector. AFM testing was performed on the surface of the PE-KBC-Mo current collector, and the results are as follows... Figure 6 As shown, the current collector surface has a uniform rough structure. This uniform surface rough structure enables mechanical interlocking between the current collector and the cathode material, thereby improving the interfacial bonding force.

[0041] The PE-KBC-Mo current collector of this embodiment was assembled into an aluminum-ion battery, and its electrical performance was tested, as follows: Graphite powder, Ketjen black, and carboxymethyl cellulose were ground in a mass ratio of 6:3:1, and then deionized water was added to form a slurry. This slurry was then evenly coated onto a PE-KBC-Mo current collector with a diameter of 8 mm and dried in a vacuum oven at 80°C for 10 hours to obtain the positive electrode sheet. Figure 1As shown, the surface of the PE-KBC-Mo current collector 1 is coated with an initial contact positive electrode material slurry 2. After coating, the positive electrode material slurry 3 and the current collector are mechanically interlocked. After drying, a positive electrode sheet with a smooth surface is formed. The uniform roughness of the PE-KBC-Mo current collector 1 significantly improves the interfacial adhesion between the current collector 1 and the coated positive electrode material slurry 3. The electrolyte is an AlCl3 / [EMIm]Cl ionic liquid composed of aluminum chloride and [EMIm]Cl in a molar ratio of 1:1.3. A high-purity aluminum sheet is used as the negative electrode. The positive electrode, negative electrode, and electrolyte are assembled into an aluminum-ion battery, and its electrochemical performance is tested.

[0042] The cyclic voltammetry curve of the aluminum-ion battery in this embodiment is as follows: Figure 7 As shown, the charge-discharge curves are as follows: Figure 8 As shown, the electrochemical impedance spectroscopy is as follows: Figure 9 As shown, the linear sweep voltammetry curve is as follows: Figure 10 As shown, the Tafel curve is as follows Figure 11 As shown, the cycle stability in aluminum-ion batteries is as follows: Figure 12 As shown, the aluminum-ion battery using the PE-KBC-Mo current collector exhibits clearly identifiable redox peaks and a highly stable charge-discharge plateau, indicating that its energy storage mechanism is dominated by the Faraday process. In this embodiment, the conductive network running through the current collector, combined with the robust interface, effectively reduces the interface impedance. Figure 9 As can be seen, the interfacial impedance of the current collector before and after cycling in this embodiment is significantly lower than that of the Mo current collector. Therefore, the current collector of this invention improves the charge transport dynamics performance of the aluminum-ion battery. Simultaneously, the PE-KBC-Mo current collector exhibits a wide voltage window in an electrolyte with AlCl3 / [EMIm]Cl = 1:1.3, thus demonstrating a strong oxidation potential. Furthermore, the flexible polyethylene substrate can effectively accommodate large-size AlCl4 cells. - and Al2Cl7 - The volume changes and lattice stresses caused by repeated insertion / extraction in graphite, such as Figure 1 As shown, the interlayer internal stress 4 of the positive electrode material is effectively released, thereby suppressing fatigue damage to the electrode structure and significantly improving the cycle life of the aluminum battery.

[0043] Example 2 A PE-KBC-Ta current collector, the preparation method of which is a polyethylene-based metal carbon current collector includes the following steps: S1. Weighing According to the required proportions of materials, accurately weigh 2.5g of polyethylene, 1.5g of Ketjen Black, and 1.0g of micronized tantalum powder, with the mass ratio of PE, KBC, and Ta being 5:3:2. S2. Ball mill The weighed KBC and Ta powders were dry ball-milled for 12 hours under a high-purity argon atmosphere. The ball mill speed was 300 rpm, the ball diameter was 3~8 mm, and the ball-to-material ratio was 30:1. S3. Secondary ball milling Add the weighed PE to the KBC and Ta powder mixture, and continue dry ball milling for 12 hours under a high-purity argon atmosphere. The ball mill speed is 300 rpm, the diameter of the ball is 3~8 mm, and the ball-to-material ratio is 30:1. Collect the powder sample after ball milling. S4. Hot pressing After the powder sample is evenly spread on the surface of the stainless steel foil, the stainless steel foil is sandwiched on the other side of the powder sample to form a stainless steel clip with the powder sample sandwiched in the middle. The stainless steel clip is heated to 135°C and then hot-pressed at this temperature. The hot-pressing pressure is 25MPa and the hot-pressing holding time is 20 minutes, thereby forming a dense, non-porous film. Then, the film was hot-calendered at 120°C with a calendering pressure of 25 MPa and a holding time of 10 minutes to obtain a film with a thickness of 90 μm. S5. Sampling After the stainless steel clips have cooled to room temperature, remove the PE-KBC-Ta current collector from the stainless steel clips.

[0044] The PE-KBC-Ta current collector obtained above was used to assemble aluminum-ion batteries and tested, as detailed below: Graphite powder, Ketjen black, and carboxymethyl cellulose (CMC) were ground in a mass ratio of 6:3:1, and deionized water was added to form a slurry. This slurry was then uniformly coated onto a PE-KBC-Ta current collector with a diameter of 8 mm and dried in a vacuum oven at 80°C for 10 hours to obtain the positive electrode. An ionic liquid (AlCl3 / [EMIm]Cl = 1:1.5) was used as the electrolyte, and a high-purity aluminum sheet was used as the negative electrode. The positive electrode, negative electrode, and electrolyte were assembled into an aluminum-ion battery, and its electrochemical performance was tested, yielding results similar to those in Example 1.

[0045] Example 3 A PE-AB-Mo current collector, the preparation method of which is a polyethylene-based metal carbon current collector includes the following steps: S1. Weighing According to the required proportions of materials, accurately weigh 3.0g of polyethylene, 1.5g of acetylene black, and 0.5g of micronized molybdenum powder. The mass ratio of PE, AB, and Mo is 6:3:1. S2. Ball mill The weighed AB and Mo powders were dry ball-milled for 36 hours under a high-purity argon atmosphere. The ball mill speed was 200 rpm, the ball diameter was 3~8 mm, and the ball-to-material ratio was 25:1. S3. Secondary ball milling Add the weighed PE to the mixture of AB and Mo powders, and continue dry ball milling for 6 hours under a high-purity argon atmosphere. The ball mill speed is 400 rpm, the diameter of the ball is 3~8 mm, and the ball-to-material ratio is 25:1. Collect the powder sample after ball milling. S4. Hot pressing After the powder sample is evenly spread on the surface of the stainless steel foil, the stainless steel foil is sandwiched on the other side of the powder sample to form a stainless steel clip with the powder sample sandwiched in the middle. The stainless steel clip is heated to 125°C and then hot-pressed at this temperature. The hot-pressing pressure is 18MPa and the hot-pressing holding time is 20 minutes, thereby forming a dense, non-porous film. Then, the film was hot-calendered at 120°C with a calendering pressure of 18 MPa and a holding time of 5 minutes to obtain a film with a thickness of 90 μm. S5. Sampling After the stainless steel clips have cooled to room temperature, remove the PE-AB-Mo current collector from the stainless steel clips.

[0046] The PE-AB-Mo current collector obtained above was used to assemble aluminum-ion batteries and tested, as detailed below: Graphite powder, Ketjen black, and carboxymethyl cellulose were ground in a mass ratio of 6:3:1, and deionized water was added to form a slurry. This slurry was then uniformly coated onto a PE-AB-Mo current collector with a diameter of 8 mm and dried in a vacuum oven at 80°C for 10 hours to obtain the positive electrode. An ionic liquid (AlCl3 / [EMIm]Cl = 1:1.3) was used as the electrolyte, and a high-purity aluminum sheet was used as the negative electrode. The positive electrode, negative electrode, and electrolyte were assembled into an aluminum-ion battery, and its electrochemical performance was tested, yielding results similar to those in Example 1.

[0047] Example 4 A PE-AB-Ta current collector, the preparation method of which is a polyethylene-based metal carbon current collector includes the following steps: S1. Weighing According to the required proportions of materials, accurately weigh 2.5g of polyethylene, 1.5g of acetylene black, and 1.0g of micronized tantalum powder. The mass ratio of PE, AB, and Ta is 5:3:2. S2. Ball mill The weighed AB and Ta powders were dry ball-milled for 48 hours under a high-purity argon atmosphere. The ball mill speed was 200 rpm, the ball diameter was 3~8 mm, and the ball-to-material ratio was 25:1. S3. Secondary ball milling Add the weighed PE to the mixture of AB and Ta powders, and continue dry ball milling for 6 hours under a high-purity argon atmosphere. The ball mill speed is 400 rpm, the diameter of the milling balls is 3~8 mm, and the ball-to-material ratio is 25:1. Collect the powder sample after ball milling. S4. Hot pressing After the powder sample is evenly spread on the surface of the stainless steel foil, the stainless steel foil is sandwiched on the other side of the powder sample to form a stainless steel clip with the powder sample sandwiched in the middle. The stainless steel clip is heated to 150°C and then hot-pressed at this temperature. The hot-pressing pressure is 25MPa and the hot-pressing holding time is 15 minutes, thereby forming a dense, non-porous film. Then, the film was hot-calendered at 120°C with a calendering pressure of 25 MPa and a holding time of 10 minutes to obtain a film with a thickness of 90 μm. S5. Sampling After the stainless steel clips have cooled to room temperature, remove the PE-AB-Ta current collector from the stainless steel clips.

[0048] The PE-AB-Ta current collector obtained above was used to assemble an aluminum-ion battery and tested, as detailed below: Graphite powder, Ketjen black, and carboxymethyl cellulose were ground in a mass ratio of 6:3:1, and deionized water was added to form a slurry. This slurry was then uniformly coated onto a PE-AB-Ta current collector with a diameter of 8 mm and dried in a vacuum oven at 80°C for 10 hours to obtain the positive electrode. An ionic liquid (AlCl3 / [EMIm]Cl = 1:1.5) was used as the electrolyte, and a high-purity aluminum sheet was used as the negative electrode. The positive electrode, negative electrode, and electrolyte were assembled into an aluminum-ion battery, and its electrochemical performance was tested, yielding results similar to those in Example 1.

[0049] Example 5 A PE-SP-Mo current collector, the preparation method of which is a polyethylene-based metal carbon current collector includes the following steps: S1. Weighing According to the required proportions of materials, accurately weigh 3.0g of polyethylene, 1.0g of Super P, and 1.0g of micronized molybdenum powder, with the mass ratio of PE, SP, and Mo being 6:2:2. S2. Ball mill The weighed SP and Mo powders were dry ball-milled for 24 hours under a high-purity argon atmosphere. The ball mill speed was 300 rpm, the ball diameter was 3~8 mm, and the ball-to-material ratio was 25:1. S3. Secondary ball milling Add the weighed PE to the SP and Mo powder mixture, and continue dry ball milling for 9 hours under a high-purity argon atmosphere. The ball mill speed is 300 rpm, the ball diameter is 3~8 mm, and the ball-to-material ratio is 25:1. Collect the powder sample after ball milling. S4. Hot pressing After the powder sample is evenly spread on the surface of the stainless steel foil, the stainless steel foil is sandwiched on the other side of the powder sample to form a stainless steel clip with the powder sample sandwiched in the middle. The stainless steel clip is heated to 135°C and then hot-pressed at this temperature. The hot-pressing pressure is 21 MPa and the hot-pressing holding time is 20 minutes, thereby forming a dense, non-porous film. Then, the film was hot-calendered at 120°C with a calendering pressure of 21 MPa and a holding time of 5 minutes to obtain a film with a thickness of 90 μm. S5. Sampling After the stainless steel clips have cooled to room temperature, remove the PE-SP-Mo current collector from the stainless steel clips.

[0050] The PE-SP-Mo current collector obtained above was used to assemble aluminum-ion batteries and tested, as detailed below: Graphite powder, Ketjen black, and carboxymethyl cellulose were ground in a mass ratio of 6:3:1, and deionized water was added to form a slurry. This slurry was then uniformly coated onto a PE-SP-Mo current collector with a diameter of 8 mm and dried in a vacuum oven at 80°C for 10 hours to obtain the positive electrode. An ionic liquid (AlCl3 / [EMIm]Cl = 1:1.3) was used as the electrolyte, and a high-purity aluminum sheet was used as the negative electrode. The positive electrode, negative electrode, and electrolyte were assembled into an aluminum-ion battery, and its electrochemical performance was tested, yielding results similar to those in Example 1.

[0051] Example 6 A PE-SP-Ta current collector, the preparation method of which is a polyethylene-based metal carbon current collector includes the following steps: S1. Weighing According to the required proportions of materials, accurately weigh 2.5g of polyethylene, 1.5g of Super P, and 1.0g of micronized tantalum powder, with the mass ratio of PE, SP, and Ta being 5:3:2. S2. Ball mill The weighed SP and Ta powders were dry ball-milled for 12 hours under a high-purity argon atmosphere. The ball mill speed was 300 rpm, the ball diameter was 3~8 mm, and the ball-to-material ratio was 20:1. S3. Secondary ball milling Add the weighed PE to the SP and Ta powder mixture, and continue dry ball milling for 12 hours under a high-purity argon atmosphere. The ball mill speed is 300 rpm, the diameter of the ball is 3~8 mm, and the ball-to-material ratio is 20:1. Collect the powder sample after ball milling. S4. Hot pressing After the powder sample is evenly spread on the surface of the stainless steel foil, the stainless steel foil is sandwiched on the other side of the powder sample to form a stainless steel clip with the powder sample sandwiched in the middle. The stainless steel clip is heated to 150°C and then hot-pressed at this temperature. The hot-pressing pressure is 18MPa and the hot-pressing holding time is 20 minutes, thereby forming a dense, non-porous film. Then, the film was hot-calendered at 120°C with a calendering pressure of 18 MPa and a holding time of 10 minutes to obtain a film with a thickness of 90 μm. S5. Sampling After the stainless steel clips have cooled to room temperature, remove the PE-SP-Ta current collector from the stainless steel clips.

[0052] The PE-SP-Ta current collector obtained above was used to assemble aluminum-ion batteries and tested, as detailed below: Graphite powder, Ketjen black, and carboxymethyl cellulose were ground in a mass ratio of 6:3:1, and deionized water was added to form a slurry. This slurry was then uniformly coated onto a PE-SP-Ta current collector with a diameter of 8 mm and dried in a vacuum oven at 80°C for 10 hours to obtain the positive electrode. An ionic liquid (AlCl3 / [EMIm]Cl = 1:1.5) was used as the electrolyte, and a high-purity aluminum sheet was used as the negative electrode. The positive electrode, negative electrode, and electrolyte were assembled into an aluminum-ion battery, and its electrochemical performance was tested, yielding results similar to those in Example 1.

[0053] All materials used in this invention are commercially available and can be purchased from retail sources.

Claims

1. A method for preparing a polyethylene-based metal carbon current collector, characterized in that, The preparation method includes the following steps: S1. Weighing According to the required proportions of the materials, accurately weigh out polyethylene, carbon nanoparticles, and micron-sized metal powder; S2. Ball mill The weighed carbon nanoparticles and micron-sized metal powders were dry ball-milled under a high-purity argon atmosphere to promote thorough mixing of the raw materials through mechanical force. S3. Secondary ball milling Weighed polyethylene was added to the mixture of carbon nanoparticles and micron-sized metal powders, and dry ball milling was carried out under the protection of high-purity argon atmosphere. Mechanical force was used to promote full mixing between the raw materials, and the powder sample was collected after completion. S4. Hot pressing After the powder sample is evenly spread on the surface of the stainless steel foil, the stainless steel foil is sandwiched on the other side of the powder sample to form a stainless steel clip with the powder sample sandwiched in the middle. The stainless steel clip is hot-pressed to make the powder sample in the stainless steel clip form a dense film. After cooling, a polyethylene-based metal carbon current collector is obtained.

2. The preparation method according to claim 1, characterized in that, In step S1, the mass ratio of PE, CBs, and Met is 5~6:2~3:1~2.

3. The preparation method according to claim 1, characterized in that, The carbon nanoparticles are selected from any one or a combination of Ketjen Black, acetylene black, and Super P.

4. The preparation method according to claim 1, characterized in that, The micron-sized metal powder is selected from micron-sized molybdenum powder and / or micron-sized tantalum powder.

5. The preparation method according to claim 1, characterized in that, In step S2, the dry ball mill operates at a speed of 200-300 rpm, a milling time of 12-48 h, a ball diameter of 3-8 mm, and a ball-to-material ratio of 20-30:

1.

6. The preparation method according to claim 1, characterized in that, In step S3, the dry ball mill operates at a speed of 300-400 rpm, a milling time of 6-12 hours, a ball diameter of 3-8 mm, and a ball-to-material ratio of 20-30:

1.

7. The preparation method according to claim 1, characterized in that, In step S4, the hot pressing pressure is 18~25MPa, the hot pressing holding time is 15~20 minutes, and the hot pressing temperature is 125~150℃.

8. The preparation method according to claim 1, characterized in that, After hot pressing in step S4, if the film thickness in the stainless steel clip is greater than the target thickness, further hot rolling treatment is performed. The hot rolling temperature is not less than the melting temperature of polyethylene until the film thickness reaches the target thickness. After cooling, a polyethylene-based metal carbon current collector is obtained.

9. An aluminum-ion battery system, characterized in that, The aluminum-ion battery system includes a current collector, a positive electrode material, a negative electrode material, and an electrolyte. The current collector is prepared by the method for preparing a polyethylene-based metal carbon current collector according to any one of claims 1-8.

10. The aluminum-ion battery system according to claim 9, characterized in that, The negative electrode material is an aluminum sheet; the positive electrode material includes graphite powder, Ketjen black, and carboxymethyl cellulose; the electrolyte is a non-aqueous electrolyte, which is an ionic liquid containing aluminum chloride and [EMIm]Cl, wherein the molar ratio of aluminum chloride to [EMIm]Cl is 1:1.3~1.5.

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