Heat-resistant and aging-resistant composite current collector base film and preparation process thereof

Abstract

This invention relates to the field of composite current collector base film materials, and discloses a heat-resistant and aging-resistant composite current collector base film and its preparation process. It is prepared by melt extrusion and stretching of the following raw materials in parts by weight: 100 parts PET resin, 12-25 parts multi-component composite reinforcing filler, and 0.5-3 parts lubricant. The multi-component composite reinforcing filler is prepared through the following steps: S1, halloysite nanotubes are composited with aminated mesoporous alumina, modified, and then loaded with an antioxidant to obtain functionalized halloysite nanotube-alumina composite particles; S2, magnesium oxide is deposited on graphene oxide, and modified to obtain a modified graphene oxide-magnesium oxide composite; S3, after blending, polymer grafting is performed to obtain the multi-component composite reinforcing filler. This invention, through the multi-component composite reinforcing filler in PET resin, can comprehensively improve the heat resistance, aging resistance, and bonding strength between the base film and the metal layer of the PET resin-based composite current collector base film.

Description

Technical Field

[0001] This invention relates to the field of composite current collector base film materials, and particularly to a heat-resistant and aging-resistant composite current collector base film and its preparation process. Background Technology

[0002] Composite current collectors typically use PET or PP films as base films, and then deposit copper or aluminum metal layers on both sides of them to form a three-layer composite structure of "metal-PET / PP-metal". Compared with traditional current collectors (aluminum foil or copper foil), composite current collectors can reduce the amount of metal used, improve energy density and safety, and therefore have been widely used.

[0003] PET base film possesses high mechanical strength and surface energy, making it a widely used base film material. For example, patent CN118144338B discloses a flame-retardant, heat-resistant composite current collector base film, and patent CN120059423A discloses a highly chemically stable composite current collector base film and its preparation method. However, PET base film suffers from deficiencies in heat resistance and aging resistance. Composite current collectors operate over a wide temperature range (e.g., up to 80℃), which poses a challenge to the thermal stability and heat aging resistance of the base film.

[0004] In existing technologies, antioxidants are typically added to improve the aging resistance of PET resin. However, antioxidants in PET systems are prone to gradually losing their effectiveness due to issues such as surface migration, resulting in a short duration of antioxidant protection. If the amount of antioxidant added is increased to extend its action time, it can easily lead to a loss of mechanical properties such as the strength and toughness of the system, as well as negative impacts such as increased costs.

[0005] Constructing a sustained-release system to continuously release antioxidants into PET base film systems can effectively improve long-term antioxidant performance. However, ordinary sustained-release structures typically use mesoporous particles (such as mesoporous silica and mesoporous alumina) loaded with antioxidants. The release rate mainly depends on the mesoporous parameters of the particles, making it difficult to achieve controllable adjustment of the release rate. This results in low flexibility when facing the needs of base film products in different application environments. For example, in scenarios with high operating temperatures or higher levels of oxidizing substances, a higher concentration of antioxidants is required, necessitating a higher release rate. In scenarios with relatively mild operating environments and longer design lifespans, a longer-lasting antioxidant is needed, requiring a longer release time and a relatively lower release rate. However, existing technologies lack reliable solutions to achieve this goal. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a heat-resistant and aging-resistant composite current collector base film and its preparation process, in order to address the shortcomings of the prior art.

[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a heat-resistant and aging-resistant composite current collector base film, which is prepared by melt extrusion and stretching of the following raw materials in parts by weight: 100 parts of PET resin, 12-25 parts of multi-component composite reinforcing filler, and 0.5-3 parts of lubricant.

[0008] The multi-component composite reinforced filler is prepared by the following steps:

[0009] S1. Halloysite nanotubes were combined with aminated mesoporous alumina, then modified with a silane coupling agent and loaded with an antioxidant to prepare functionalized halloysite nanotube-alumina composite particles.

[0010] S2. Magnesium oxide is deposited on graphene oxide and then modified with a silane coupling agent to prepare a modified graphene oxide-magnesium oxide composite.

[0011] S3. Functionalized halloysite nanotube-alumina composite particles are blended with modified graphene oxide-magnesium oxide composite particles and then polymer grafted to obtain the multi-component composite reinforced filler.

[0012] Preferably, the multi-component composite reinforced filler is prepared by the following steps:

[0013] S1. Preparation of functionalized halloysite nanotube-alumina composite particles:

[0014] S1-1. Mesoporous alumina and 3-aminopropyltriethoxysilane are mixed in ethanol, heated and stirred to react, and aminated mesoporous alumina is obtained.

[0015] S1-2. Halloysite nanotubes, sodium chloride, and sulfuric acid are added to deionized water and heated under ultrasonic conditions to expand the pores.

[0016] Halloysite nanotubes after pore-expanding treatment, cerium chloride, and aminated mesoporous alumina were dispersed in deionized water, and then urea was added. The resulting mixture was transferred to a reaction vessel and reacted under heating. After the reaction was completed, the solid product was separated to obtain halloysite nanotube-alumina composite particles.

[0017] S1-3. The surface of halloysite nanotube-alumina composite particles was modified with vinyltriethoxysilane to obtain modified halloysite nanotube-alumina composite particles.

[0018] S1-4, Antioxidant loading: Modified halloysite nanotube-alumina composite particles were added to an antioxidant solution, ultrasonically dispersed, and then shaken on a shaker under heating. After the reaction was completed, the solid product was separated to obtain functionalized halloysite nanotube-alumina composite particles.

[0019] S2. Preparation of modified graphene oxide:

[0020] S2-1, Deposition of magnesium oxide: Graphene oxide, magnesium chloride, and polyethylene glycol are added to deionized water, ultrasonically dispersed, pH adjusted to alkaline, heated to react, filtered after the reaction is completed, and the solid product is calcined to obtain a graphene oxide-magnesium oxide composite.

[0021] S2-2. The surface of the graphene oxide-magnesium oxide composite was modified with vinyltriethoxysilane to obtain the modified graphene oxide-magnesium oxide composite.

[0022] S3. Preparation of multi-component composite reinforced fillers:

[0023] S3-1. Halloysite nanotube-alumina composite particles, modified graphene oxide-magnesium oxide composite, and sodium dodecylbenzenesulfonate are mixed and dispersed in toluene to obtain a mixed particle dispersion.

[0024] S3-2. Styrene, glycidyl methacrylate, acrylonitrile, and azobisisobutyronitrile are added to toluene, and after stirring with nitrogen, a mixed particle dispersion is added. Nitrogen is then continued to be purged and stirred, and the mixture is heated to react. After the reaction is complete, the solid product is separated to obtain the multi-component composite reinforcing filler.

[0025] Preferably, the average pore size of the mesoporous alumina is smaller than the inner diameter of the halloysite nanotubes.

[0026] Preferably, the mesoporous alumina has an average pore size of 2-10 nm, and the halloysite nanotubes have an inner diameter of 10-50 nm.

[0027] Preferably, the antioxidant is selected from at least one of antioxidants B215, 168, 330, 1076, 626, 618, and PL-440.

[0028] Preferably, the multi-component composite reinforced filler is prepared by the following steps:

[0029] S1. Preparation of functionalized halloysite nanotube-alumina composite particles:

[0030] S1-1. Mesoporous alumina is dispersed in ethanol, and 3-aminopropyltriethoxysilane is added under stirring. The mixture is heated and refluxed under stirring to separate the solid product and obtain aminated mesoporous alumina.

[0031] S1-2. Halloysite nanotubes, sodium chloride, and sulfuric acid are added to deionized water and ultrasonically treated under heating to expand the pores.

[0032] Halloysite nanotubes after pore-expanding treatment, cerium chloride, and aminated mesoporous alumina were added to deionized water, ultrasonically dispersed, then urea was added and stirred. The resulting mixture was transferred to a reaction vessel and reacted under heating. After the reaction was completed, the solid product was separated to obtain halloysite nanotube-alumina composite particles.

[0033] S1-3, Surface modification: Halloysite nanotube-alumina composite particles were added to a mixture of deionized water and ethanol, ultrasonically dispersed, vinyltriethoxysilane was added under stirring, and the mixture was heated and stirred under reflux. After the reaction was completed, the solid product was separated to obtain modified halloysite nanotube-alumina composite particles.

[0034] S1-4, Antioxidant loading: Modified halloysite nanotube-alumina composite particles were added to a toluene solution of antioxidant B215, ultrasonically dispersed, and then shaken on a shaker under heating. After the reaction was completed, the solid product was separated to obtain functionalized halloysite nanotube-alumina composite particles.

[0035] S2. Preparation of modified graphene oxide:

[0036] S2-1, Deposition of magnesium oxide: Graphene oxide, magnesium chloride, and polyethylene glycol are added to deionized water, ultrasonically dispersed, pH adjusted to alkaline, heated to react, filtered after the reaction is completed, and the solid product is calcined to obtain a graphene oxide-magnesium oxide composite.

[0037] S2-2, Surface modification: The graphene oxide-magnesium oxide composite was added to a mixture of deionized water and ethanol, ultrasonically dispersed, and vinyltriethoxysilane was added under stirring. The mixture was heated and stirred under reflux. After the reaction was completed, the solid product was separated to obtain the modified graphene oxide-magnesium oxide composite.

[0038] S3. Preparation of multi-component composite reinforced fillers:

[0039] S3-1. Halloysite nanotube-alumina composite particles, modified graphene oxide-magnesium oxide composite, and sodium dodecylbenzenesulfonate were mixed and added to toluene, and ultrasonically dispersed to obtain a mixed particle dispersion.

[0040] S3-2. Styrene, glycidyl methacrylate, acrylonitrile, and azobisisobutyronitrile were added to toluene, and after stirring with nitrogen gas, the mixed particle dispersion was added. Nitrogen gas was continued to be purged and stirred, and the temperature was increased. The reaction was stirred under a nitrogen atmosphere. After the reaction was completed, the solid product was separated to obtain the multi-component composite reinforcing filler.

[0041] Preferably, step S1 specifically includes:

[0042] S1-1. Add 0.5-2 g of mesoporous alumina to 30-120 mL of ethanol, ultrasonically disperse for 30-120 min, add 0.2-0.8 g of 3-aminopropyltriethoxysilane while stirring, stir and reflux at 65-80 °C for 4-12 h, centrifuge, wash the precipitate with ethanol, and vacuum dry at 80-100 °C for 5-20 h to obtain aminated mesoporous alumina.

[0043] S1-2. Add halloysite nanotubes, sodium chloride, and sulfuric acid to deionized water, and control the concentration of sulfuric acid in the resulting mixture to be 1-3 mol / L, the concentration of halloysite nanotubes to be 5-20 mg / mL, and the concentration of sodium chloride to be 1.5-6 mg / mL. Sonicate at 50-75℃ for 3-10 h, centrifuge, wash the precipitate with deionized water until neutral, and vacuum dry at 90-110℃ for 6-24 h to complete the pore expansion treatment.

[0044] Add 1-4g of halloysite nanotubes after pore-expanding treatment, 0.35-1.4g of cerium chloride, and 0.6-2.4g of aminated mesoporous alumina to 90-360mL of deionized water and ultrasonically disperse for 0.5-2h. Then add 0.075-0.3g of urea and stir for 15-60min. Transfer the resulting mixture to a reaction vessel and react at 160-200℃ for 10-32h. Cool to room temperature, centrifuge, wash the precipitate with deionized water, and vacuum dry at 90-110℃ for 6-24h to obtain halloysite nanotube-alumina composite particles.

[0045] S1-3, Surface modification: Add 0.5-2g halloysite nanotube-alumina composite particles to a mixture of 50-200mL deionized water and ethanol in a volume ratio of 1:5, ultrasonically disperse for 30-90min, add 0.15-0.7g vinyltriethoxysilane under stirring, stir and reflux at 60-80℃ for 4-16h, centrifuge, wash the precipitate with ethanol, and vacuum dry at 70-90℃ for 5-24h to obtain modified halloysite nanotube-alumina composite particles;

[0046] S1-4, Antioxidant Loading: Take 1-4g of modified halloysite nanotube-alumina composite particles and add them to 50-200mL of a toluene solution containing 2-15% antioxidant B215. Disperse the particles ultrasonically for 0.5-2h, then shake them on a shaker at 50-70℃ for 6-24h. Filter the mixture, wash the precipitate with ethanol, and vacuum dry it at 70-90℃ for 6-24h to obtain functionalized halloysite nanotube-alumina composite particles.

[0047] Preferably, step S2 specifically includes:

[0048] S2-1, Deposition of magnesium oxide: Add 0.5-2g graphene oxide, 0.3-1.5g magnesium chloride, and 0.1-0.5g polyethylene glycol to 50-200mL of deionized water, sonicate for 30-90min, adjust the pH to 8-10 with 15-25wt% ammonia, react at 50-70℃ for 1.5-6h, filter, wash with deionized water, dry at 80-100℃ for 4-16h, and then calcine at 550-700℃ for 1-4h to obtain graphene oxide-magnesium oxide composite.

[0049] S2-2, Surface modification: Add 0.5-2g of graphene oxide-magnesium oxide composite to a mixture of 30-150mL of deionized water and ethanol in a volume ratio of 1:5, and ultrasonically disperse for 30-90min. Add 0.15-0.5g of vinyltriethoxysilane while stirring, and reflux at 60-80℃ for 4-16h. Centrifuge, wash the precipitate with ethanol, and vacuum dry at 70-90℃ for 5-24h to obtain the modified graphene oxide-magnesium oxide composite.

[0050] Preferably, step S3 specifically includes:

[0051] S3-1. Mix 1.75-7g halloysite nanotube-alumina composite particles, 0.75-3g modified graphene oxide-magnesium oxide composite, and 0.6-2.4g sodium dodecylbenzenesulfonate and add them to 60-240mL toluene. Disperse the mixture by ultrasonication for 0.75-3h to obtain a mixed particle dispersion.

[0052] S3-2. Add 5.5-22g styrene, 2.5-10g glycidyl methacrylate, 2-8g acrylonitrile, and 0.2-0.8g azobisisobutyronitrile to 50-200mL of toluene. Stir under nitrogen for 15-60min, then add the mixed particle dispersion. Continue stirring under nitrogen for 30-120min. Heat to 75-85℃ and react under nitrogen atmosphere for 4-16h. Cool to room temperature, wash the product with toluene and ethanol sequentially, and vacuum dry at 70-95℃ for 6-24h to obtain the multi-component composite reinforced filler.

[0053] Preferably, the multi-component composite reinforced filler is prepared by the following steps:

[0054] S1. Preparation of functionalized halloysite nanotube-alumina composite particles:

[0055] S1-1. Add 1g of mesoporous alumina to 60mL of ethanol, sonicate for 60min, add 0.4g of 3-aminopropyltriethoxysilane while stirring, stir and reflux at 70℃ for 8h, centrifuge, wash the precipitate with ethanol, and vacuum dry at 90℃ for 10h to obtain aminated mesoporous alumina.

[0056] S1-2. Halloysite nanotubes, sodium chloride, and sulfuric acid were added to deionized water. The concentration of sulfuric acid in the resulting mixture was controlled to be 2 mol / L, the concentration of halloysite nanotubes to be 10 mg / mL, and the concentration of sodium chloride to be 3 mg / mL. The mixture was ultrasonically treated at 60℃ for 7 h, centrifuged, and the precipitate was washed with deionized water until neutral. The precipitate was then vacuum dried at 100℃ for 12 h to complete the pore expansion treatment.

[0057] 2g of halloysite nanotubes with expanded pores, 0.7g of cerium chloride, and 1.2g of aminated mesoporous alumina were added to 180mL of deionized water and ultrasonically dispersed for 1h. Then, 0.15g of urea was added and stirred for 30min. The resulting mixture was transferred to a reaction vessel and reacted at 180℃ for 16h. After cooling to room temperature, the mixture was centrifuged, and the precipitate was washed with deionized water and vacuum dried at 100℃ for 12h to obtain halloysite nanotube-alumina composite particles.

[0058] S1-3, Surface modification: 1g halloysite nanotube-alumina composite particles were added to a mixture of 100mL deionized water and ethanol in a volume ratio of 1:5, and ultrasonically dispersed for 45min. 0.35g vinyltriethoxysilane was added under stirring, and the mixture was stirred and refluxed at 70℃ for 8h. After centrifugation, the precipitate was washed with ethanol and vacuum dried at 80℃ for 10h to obtain modified halloysite nanotube-alumina composite particles.

[0059] S1-4, Antioxidant loading: Take 2g of modified halloysite nanotube-alumina composite particles and add them to 100mL of a 5% toluene solution of antioxidant B215. Disperse by ultrasonication for 1h, then shake in a shaker at 60℃ for 12h. Filter, wash the precipitate with ethanol, and vacuum dry at 80℃ for 12h to obtain functionalized halloysite nanotube-alumina composite particles.

[0060] S2. Preparation of modified graphene oxide:

[0061] S2-1, Deposited magnesium oxide:

[0062] 1g of graphene oxide, 0.75g of magnesium chloride, and 0.25g of polyethylene glycol were added to 100mL of deionized water and ultrasonically dispersed for 45min. The pH was adjusted to 9 with 20wt% ammonia and reacted at 60℃ for 3h. The mixture was then filtered, washed with deionized water, dried at 90℃ for 8h, and then calcined at 600℃ for 2h to obtain the graphene oxide-magnesium oxide composite.

[0063] S2-2, Surface modification: 1g of graphene oxide-magnesium oxide composite was added to a mixture of 75mL of deionized water and ethanol in a volume ratio of 1:5, and ultrasonically dispersed for 45min. 0.25g of vinyltriethoxysilane was added under stirring, and the mixture was stirred and refluxed at 70℃ for 8h. After centrifugation, the precipitate was washed with ethanol and vacuum dried at 80℃ for 10h to obtain the modified graphene oxide-magnesium oxide composite.

[0064] S3. Preparation of multi-component composite reinforced fillers:

[0065] S3-1. Mix 3.5g halloysite nanotube-alumina composite particles, 1.5g modified graphene oxide-magnesium oxide composite, and 1.2g sodium dodecylbenzenesulfonate and add them to 120mL toluene. Disperse the mixture by ultrasonication for 1.5h to obtain a mixed particle dispersion.

[0066] S3-2. Add 11g styrene, 5g glycidyl methacrylate, 4g acrylonitrile, and 0.4g azobisisobutyronitrile to 100mL toluene. Stir under nitrogen for 30min, then add the mixed particle dispersion. Continue stirring under nitrogen for 60min, raise the temperature to 80℃, and stir under nitrogen atmosphere for 8h. Cool to room temperature, wash the product with toluene and ethanol sequentially, and dry under vacuum at 90℃ for 12h to obtain the multi-component composite reinforcing filler.

[0067] Preferably, the lubricant is at least one of pentaerythritol stearate and N,N'-ethylene bis-stearamide.

[0068] This invention also provides a preparation process for the heat-resistant and aging-resistant composite current collector substrate film as described above, comprising the following steps:

[0069] PET resin, multi-component composite reinforcing filler, and lubricant are mixed evenly according to the weight ratio. The resulting mixture is melt-extruded at 250-260℃, cooled, and cast into sheets. After preheating, the cast sheets are stretched longitudinally and then stretched transversely to obtain a heat-resistant and aging-resistant composite current collector base film.

[0070] Preferably, the longitudinal stretch ratio is 2.5-3.8 times and the transverse stretch ratio is 3.0-4.5 times.

[0071] The beneficial effects of this invention are:

[0072] This invention improves the heat resistance, aging resistance, and bonding strength between the composite current collector film and the metal layer of PET resin by using multi-component composite reinforcing fillers in PET resin.

[0073] In this invention, the halloysite nanotube-alumina composite particles obtained by combining aminated mesoporous alumina with halloysite nanotubes after pore-expanding treatment can form pore structures with two scales: a large pore structure formed by the inner diameter of the halloysite nanotube lumen and a small pore structure formed by the mesoporous structure of the aminated mesoporous alumina, with the large pore structure being larger than the small pore structure. The size of the pore structure affects the slow-release rate. Therefore, when the halloysite nanotube-alumina composite particles are loaded with antioxidant B215, the slow-release rate of antioxidant B215 loaded in the halloysite nanotubes will be greater than the slow-release rate of the aminated mesoporous alumina. The slow-release rate of the composite particles can be adjusted by regulating the ratio of aminated mesoporous alumina to halloysite nanotubes in the composite particles. For example, increasing the content of aminated mesoporous alumina increases the proportion of microporous structures, which reduces the slow-release rate of the composite particles, resulting in a longer-lasting antioxidant slow-release effect. This is suitable for applications with relatively mild environments and longer design lifespans. Conversely, decreasing the content of aminated mesoporous alumina reduces the proportion of microporous structures, increasing the slow-release rate of the composite particles. This is suitable for applications with high temperatures or higher levels of oxidizing agents. This rate-adjustable slow-release structure design allows for greater flexibility in its application within base films, better meeting the needs of different usage scenarios.

[0074] In this invention, halloysite nanotube-alumina composite particles and modified graphene oxide are uniformly mixed. The two particles can interact through hydrogen bonds to form a composite network structure. The two-dimensional structure of modified graphene oxide serves as the main body of the network structure, while halloysite nanotubes with long diameter structures are interwoven in the main body of the network structure to form a network skeleton, providing favorable support. The synergy between the two significantly enhances the effect of improving the strength of the base film. Meanwhile, PET molecules can penetrate through the network to form an interpenetrating network structure, which further enhances the strength of the base film. Attached Figure Description

[0075] Figure 1 Infrared absorption spectra of the aminated mesoporous alumina (SM-Al2O3) and modified halloysite nanotube-alumina composite particles (HNTs@SM-Al2O3) prepared in Example 1;

[0076] Figure 2 The XRD pattern of the graphene oxide-magnesium oxide composite prepared in Example 1;

[0077] Figure 3 Slow-release curves of functionalized halloysite nanotube-alumina composite particles with different aminated mesoporous alumina contents. Detailed Implementation

[0078] The present invention will be further described in detail below with reference to embodiments, so that those skilled in the art can implement it based on the description.

[0079] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0080] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the materials and reagents used in the following examples are commercially available. For examples where specific conditions are not specified, conventional conditions or conditions recommended by the manufacturer are followed. For reagents or instruments whose manufacturers are not specified, they are all commercially available products.

[0081] This invention provides a heat-resistant and aging-resistant composite current collector base film, characterized in that it is prepared by melt extrusion and stretching of the following raw materials in parts by weight: 100 parts PET resin, 12-25 parts multi-component composite reinforcing filler, and 0.5-3 parts lubricant.

[0082] The preparation process of this heat-resistant and aging-resistant composite current collector base film includes the following steps:

[0083] PET resin, multi-component composite reinforcing filler, and lubricant are mixed evenly according to the weight ratio. The resulting mixture is melt-extruded at 250-260℃, cooled, and cast into sheets. After preheating, the cast sheets are stretched longitudinally and then stretched transversely to obtain a heat-resistant and aging-resistant composite current collector base film.

[0084] In a preferred embodiment, the lubricant is at least one of pentaerythritol stearate and N,N'-ethylene bis-stearamide.

[0085] In a preferred embodiment, the multi-component composite reinforcing filler is prepared by the following steps:

[0086] S1. Halloysite nanotubes were combined with aminated mesoporous alumina, then modified with a silane coupling agent and loaded with an antioxidant to prepare functionalized halloysite nanotube-alumina composite particles.

[0087] S2. Magnesium oxide is deposited on graphene oxide and then modified with a silane coupling agent to prepare a modified graphene oxide-magnesium oxide composite.

[0088] S3. Functionalized halloysite nanotube-alumina composite particles are blended with modified graphene oxide-magnesium oxide composite particles and then polymer grafted to obtain the multi-component composite reinforced filler.

[0089] In a preferred embodiment, the multi-component composite reinforcing filler is prepared by the following steps:

[0090] S1. Preparation of functionalized halloysite nanotube-alumina composite particles:

[0091] S1-1. Add 0.5-2 g of mesoporous alumina to 30-120 mL of ethanol, ultrasonically disperse for 30-120 min, add 0.2-0.8 g of 3-aminopropyltriethoxysilane while stirring, stir and reflux at 65-80 °C for 4-12 h, centrifuge, wash the precipitate with ethanol, and vacuum dry at 80-100 °C for 5-20 h to obtain aminated mesoporous alumina.

[0092] S1-2. Add halloysite nanotubes, sodium chloride, and sulfuric acid to deionized water, and control the concentration of sulfuric acid in the resulting mixture to be 1-3 mol / L, the concentration of halloysite nanotubes to be 5-20 mg / mL, and the concentration of sodium chloride to be 1.5-6 mg / mL. Sonicate at 50-75℃ for 3-10 h, centrifuge, wash the precipitate with deionized water until neutral, and vacuum dry at 90-110℃ for 6-24 h to complete the pore expansion treatment.

[0093] Add 1-4g of halloysite nanotubes after pore-expanding treatment, 0.35-1.4g of cerium chloride, and 0.6-2.4g of aminated mesoporous alumina to 90-360mL of deionized water and ultrasonically disperse for 0.5-2h. Then add 0.075-0.3g of urea and stir for 15-60min. Transfer the resulting mixture to a reaction vessel and react at 160-200℃ for 10-32h. Cool to room temperature, centrifuge, wash the precipitate with deionized water, and vacuum dry at 90-110℃ for 6-24h to obtain halloysite nanotube-alumina composite particles.

[0094] S1-3. Surface modification: Add 0.5-2g halloysite nanotube-alumina composite particles to a mixture of 50-200mL deionized water and ethanol in a volume ratio of 1:5, and ultrasonically disperse for 30-90min. Add 0.15-0.7g vinyltriethoxysilane while stirring, and reflux at 60-80℃ for 4-16h. Centrifuge, wash the precipitate with ethanol, and vacuum dry at 70-90℃ for 5-24h to obtain modified halloysite nanotube-alumina composite particles.

[0095] S1-4, Antioxidant loading: Take 1-4g of modified halloysite nanotube-alumina composite particles and add them to 50-200mL of a toluene solution of antioxidant B215 with a concentration of 2-15%. Disperse the particles ultrasonically for 0.5-2h, then shake them on a shaker at 50-70℃ for 6-24h. Filter the mixture, wash the precipitate with ethanol, and vacuum dry it at 70-90℃ for 6-24h to obtain functionalized halloysite nanotube-alumina composite particles.

[0096] S2. Preparation of modified graphene oxide:

[0097] S2-1, Deposited magnesium oxide:

[0098] S2-1, Deposition of magnesium oxide: Add 0.5-2g graphene oxide, 0.3-1.5g magnesium chloride, and 0.1-0.5g polyethylene glycol to 50-200mL of deionized water, sonicate for 30-90min, adjust the pH to 8-10 with 15-25wt% ammonia, react at 50-70℃ for 1.5-6h, filter, wash with deionized water, dry at 80-100℃ for 4-16h, and then calcine at 550-700℃ for 1-4h to obtain graphene oxide-magnesium oxide composite.

[0099] S2-2, Surface modification: Add 0.5-2g of graphene oxide-magnesium oxide composite to a mixture of 30-150mL of deionized water and ethanol in a volume ratio of 1:5, ultrasonically disperse for 30-90min, add 0.15-0.5g of vinyltriethoxysilane while stirring, stir and reflux at 60-80℃ for 4-16h, centrifuge, wash the precipitate with ethanol, and vacuum dry at 70-90℃ for 5-24h to obtain the modified graphene oxide-magnesium oxide composite;

[0100] S3. Preparation of multi-component composite reinforced fillers:

[0101] S3-1. Mix 1.75-7g halloysite nanotube-alumina composite particles, 0.75-3g modified graphene oxide-magnesium oxide composite, and 0.6-2.4g sodium dodecylbenzenesulfonate and add them to 60-240mL toluene. Disperse the mixture by ultrasonication for 0.75-3h to obtain a mixed particle dispersion.

[0102] S3-2. Add 5.5-22g styrene, 2.5-10g glycidyl methacrylate, 2-8g acrylonitrile, and 0.2-0.8g azobisisobutyronitrile to 50-200mL of toluene. Stir under nitrogen for 15-60min, then add the mixed particle dispersion. Continue stirring under nitrogen for 30-120min. Heat to 75-85℃ and react under nitrogen atmosphere for 4-16h. Cool to room temperature, wash the product with toluene and ethanol sequentially, and vacuum dry at 70-95℃ for 6-24h to obtain the multi-component composite reinforced filler.

[0103] In a preferred embodiment, the mesoporous alumina has an average pore size of 2-10 nm, and the halloysite nanotubes have an inner diameter of 10-50 nm.

[0104] The mesoporous alumina can be a conventional commercially available product or it can be homemade. In a preferred embodiment, it is homemade through the following steps:

[0105] Aluminum nitrate and glucose were added to deionized water and stirred. The pH was adjusted to alkaline with sodium hydroxide and the reaction was carried out under sonication. The resulting product was transferred to a reaction vessel and reacted at 170-210℃ for 5-20 hours. After cooling, the product was washed, dried, and then calcined at 800-1000℃ for 1-4 hours. After cooling and grinding, mesoporous alumina was obtained.

[0106] In a more preferred embodiment, the self-made process is carried out through the following steps:

[0107] Add 2g of aluminum nitrate and 5g of glucose to 50mL of deionized water, stir for 5min, adjust the pH to 10 with sodium hydroxide, react under sonication for 2h, transfer the product to a reaction vessel, react at 190℃ for 10h, cool to room temperature, wash the product with deionized water, dry at 120℃ for 4h, then calcine at 900℃ for 2h, cool, grind, and obtain mesoporous alumina.

[0108] In a preferred embodiment, the graphene oxide is pre-purified using a mixed acid composed of concentrated nitric acid and hydrogen peroxide. The specific steps are as follows: the graphene oxide is added to a mixed acid composed of 65 wt% concentrated nitric acid and 20 wt% hydrogen peroxide in a volume ratio of 2:1, ultrasonically treated under heating, filtered, precipitated and washed until neutral, and dried to obtain purified graphene oxide.

[0109] In a more preferred embodiment, the purification process of graphene oxide is as follows: 5g of graphene oxide is added to 150mL of a mixed acid consisting of 65wt% concentrated nitric acid and 20wt% hydrogen peroxide in a volume ratio of 2:1, ultrasonically treated at 70°C for 4h, filtered, the precipitate is washed with deionized water until neutral, and vacuum dried at 100°C for 12h to obtain purified graphene oxide.

[0110] Invention Mechanism

[0111] To comprehensively improve the heat resistance, aging resistance, and bonding strength between the base film and the metal layer of the composite current collector based on PET resin, this invention achieves this through multi-component composite reinforcing filler in PET resin. The mechanism of the multi-component composite reinforcing filler is explained in detail below to facilitate understanding of this invention.

[0112] I. Preparation process

[0113] This multi-component composite reinforcing filler is obtained by blending functionalized halloysite nanotube-alumina composite particles with modified graphene oxide and grafting polymers.

[0114] 1. Preparation of functionalized halloysite nanotube-alumina composite particles:

[0115] First, mesoporous alumina was modified with 3-aminopropyltriethoxysilane to prepare aminated mesoporous alumina.

[0116] Halloysite nanotubes were enlarged by treating them with sodium chloride and sulfuric acid to increase the inner diameter of the tubes. Then, the enlarged halloysite nanotubes were blended with aminated mesoporous alumina and cerium chloride was added as a dopant. The halloysite nanotubes and aminated mesoporous alumina were then combined using a one-pot hydrothermal method to prepare halloysite nanotube-alumina composite particles.

[0117] In this step, cerium ions can combine with hydroxyl groups on the surface of halloysite nanotubes and hydroxyl and amino groups on the surface of aminated mesoporous alumina through electrostatic adsorption and / or coordination, thereby playing a role in bonding. Then, cerium dioxide is formed through a hydrothermal reaction, so that halloysite nanotubes and aminated mesoporous alumina are firmly connected through cerium dioxide as a bonding agent, forming a uniformly mixed composite particle.

[0118] Next, vinyltriethoxysilane was used to modify the surface of halloysite nanotube-alumina composite particles to obtain modified halloysite nanotube-alumina composite particles, thereby improving their dispersibility and introducing double bonds on their surface.

[0119] Finally, antioxidant B215 was loaded onto the modified halloysite nanotube-alumina composite particles by impregnation method to obtain functionalized halloysite nanotube-alumina composite particles.

[0120] 2. Preparation of modified graphene oxide:

[0121] First, the graphene oxide is purified using a mixed acid consisting of concentrated nitric acid and hydrogen peroxide to remove impurities and enrich the carboxyl groups on the surface of the graphene oxide, so as to facilitate further modification.

[0122] Then, magnesium oxide is deposited in situ on the surface of graphene oxide to obtain a graphene oxide-magnesium oxide composite. In this step, the magnesium ions added to the raw materials combine with the carboxyl groups on the surface of graphene oxide through electrostatic adsorption and / or coordination, and then form magnesium oxide under calcination, thereby achieving chemical bonding and depositing a large number of magnesium oxide particles that are uniformly and firmly distributed on the surface of graphene oxide.

[0123] Finally, surface modification with vinyltriethoxysilane was performed to improve its dispersibility and introduce double bonds on its surface.

[0124] 3. Halloysite nanotube-alumina composite particles are blended with modified graphene oxide to obtain mixed particles. Styrene, glycidyl methacrylate, and acrylonitrile are used as polymerization monomers, and azobisisobutyronitrile is used as an initiator. Glycidyl methacrylate-styrene-acrylonitrile terpolymer is grafted onto the surface of the mixed particles to finally obtain a multi-component composite reinforced filler.

[0125] II. Mechanism of Action

[0126] 1. Functionalized halloysite nanotube-alumina composite particles

[0127] (1) In the functional halloysite nanotube-alumina composite particles of the present invention, a multi-scale porous loading system with adjustable sustained release rate is constructed by combining nanoparticles with different pore structures:

[0128] Halloysite nanotubes have a tubular structure, with typical parameters of an outer diameter of 10-50 nm, an inner diameter of 10-20 nm, and a length of 0.5-2 μm. After the pore-expansion treatment of this invention, their inner diameter can reach 15-40 nm. Aminated mesoporous alumina has abundant mesoporous structures with mesopore diameters of 2-10 nm, which are smaller than the inner diameter of the halloysite nanotubes after pore-expansion treatment.

[0129] First, by loading antioxidant B215 onto halloysite nanotubes and aminated mesoporous alumina, its slow release can be achieved, thus achieving the purpose of long-term release of antioxidant. This can provide the base film with a longer-lasting antioxidant protection function, avoiding the problems of excessively high initial concentration, short antioxidant duration, and risk of damaging the mechanical strength of the base film when antioxidant is directly added to the system.

[0130] Furthermore, in this invention, the halloysite nanotube-alumina composite particles obtained by combining aminated mesoporous alumina with halloysite nanotubes after pore-expanding treatment can form pore structures with two scales: a large pore structure formed by the inner diameter of the halloysite nanotube lumen and a small pore structure formed by the mesoporous structure of the aminated mesoporous alumina, with the large pore structure being larger than the small pore structure. The size of the pore structure affects the slow-release rate. Therefore, when the halloysite nanotube-alumina composite particles are loaded with antioxidant B215, the slow-release rate of antioxidant B215 loaded in the halloysite nanotubes will be greater than the slow-release rate of the aminated mesoporous alumina. The slow-release rate of the composite particles can be adjusted by regulating the ratio of aminated mesoporous alumina to halloysite nanotubes in the composite particles. For example, increasing the content of aminated mesoporous alumina increases the proportion of microporous structures, which reduces the slow-release rate of the composite particles, resulting in a longer-lasting antioxidant release effect. This is suitable for applications with relatively mild environments and longer design lifespans. Conversely, decreasing the content of aminated mesoporous alumina reduces the proportion of microporous structures, increasing the slow-release rate of the composite particles. This is suitable for applications with high temperatures or higher levels of oxidizing agents. This adjustable slow-release structure design allows for greater flexibility in its application within base films, better meeting the needs of different usage scenarios.

[0131] (2) In addition to providing a slow-release function, mesoporous alumina can also effectively improve the heat resistance and strength of the base film. The amination treatment introduces a large number of amino groups on the surface of mesoporous alumina, which can promote the composite of halloysite nanotubes and amination mesoporous alumina. At the same time, in the subsequent preparation of composite current collectors, the interaction between amino groups and metals can improve the bonding force between the base film and the metal layer.

[0132] (3) Halloysite nanotubes can effectively improve the mechanical strength of the base film and accelerate the crystallization rate of PET, thereby improving its stability and heat resistance (Xing Tianhao, Luo Chunming, Tang Anbin. Preparation and performance study of PET / modified halloysite nanotube composite film [J]. Journal of Southwest University of Science and Technology, 2015, 30(1):4.DOI:10.3969 / j.issn.1671-8755.2015.01.003.). In addition, halloysite nanotubes form tortuous paths in the PET matrix, which can improve its barrier properties (Xing Tianhao. Barrier properties study of PET / haloysite composite film [D]. Southwest University of Science and Technology, 2016.), thereby enhancing its acid and alkali resistance and antioxidant properties.

[0133] (4) In addition to playing a role in the preparation process, the cerium dioxide doped in halloysite nanotube-alumina composite particles can efficiently remove reactive oxygen free radicals through its reversible redox properties, thereby improving the anti-aging performance.

[0134] 2. Modified graphene oxide

[0135] (1) Graphene oxide can improve the oxygen permeability of the base film, thereby improving its anti-aging performance; as a high-strength, high-temperature resistant two-dimensional material, it can also significantly improve the heat resistance and mechanical strength of PET base film.

[0136] (2) Magnesium oxide can improve the crystallization behavior of PET through heterogeneous nucleation mechanism, promote the orderly arrangement of molecular chains, significantly improve the crystallization rate and crystal density, promote the generation of more and smaller crystals, reduce internal stress, thereby optimize mechanical properties and balance toughness and strength. Magnesium oxide particles deposited on the surface of graphene oxide can serve as connecting nodes and stress nodes, promote the formation of a three-dimensional network structure of graphene oxide, improve strength, and promote the flattening and unfolding of graphene oxide through mechanical pulling and other actions, reducing its curling, thereby facilitating its performance enhancement in PET base film.

[0137] 3. Surface modification

[0138] In this invention, surface modification of modified halloysite nanotube-alumina composite particles and graphene oxide-magnesium oxide composites using vinyltriethoxysilane can introduce double bonds on the surface of inorganic particles. These double bonds can participate in monomer polymerization during subsequent blending modification, thereby ensuring successful grafting of polymers onto their surfaces.

[0139] 4. Polymer grafting

[0140] Halloysite nanotube-alumina composite particles and graphene oxide-magnesium oxide composites both suffer from poor compatibility with PET resin, making uniform dispersion difficult. In this invention, by in-situ grafting a glycidyl methacrylate-styrene-acrylonitrile terpolymer onto the surface of the blended particles, the compatibility between both and the PET system can be significantly improved, enhancing the impact strength and elongation at break of PET and mitigating its brittleness. In the glycidyl methacrylate-styrene-acrylonitrile terpolymer, the epoxy groups from glycidyl methacrylate can chemically react with the terminal hydroxyl (–OH) or terminal carboxyl (–COOH) groups of PET, forming an in-situ copolymer at the blending interface, thereby reducing interfacial tension and enhancing the compatibility between the two phases. The introduction of acrylonitrile helps to enhance the polarity and rigidity of the polymer chain, thus improving the chemical corrosion resistance and heat resistance of PET.

[0141] 5. Synergy between halloysite nanotube-alumina composite particles and modified graphene oxide

[0142] (1) In the multi-component composite reinforcing filler, halloysite nanotube-alumina composite particles and modified graphene oxide are uniformly mixed. The two can interact through hydrogen bonds to form a composite network structure. The two-dimensional structure of modified graphene oxide serves as the main body of the network structure. Halloysite nanotubes with long diameter structure are interwoven in the main body of the network structure to form a network skeleton, providing favorable support. The mutual cooperation between the two significantly enhances the effect of improving the strength of the base film. Meanwhile, PET molecules can penetrate through the network to form an interpenetrating network structure, which improves the strength of the base film.

[0143] (2) The multi-component composite reinforcing filler contains abundant amino, carboxyl and hydroxyl groups, which can help improve the bonding force between the base film and the metal layer plated on its surface. For example, when a copper layer is subsequently plated on the surface of the base film by electroplating, the amino, carboxyl and hydroxyl groups can combine with copper ions through coordination and electrostatic adsorption. During the electroplating process, it can promote the rapid and uniform adhesion of copper ions, thereby improving the electroplating efficiency and the density of the coating. In the later stage, it can effectively improve the bonding strength between the copper layer and the base film.

[0144] The above is the general concept of the present invention. Based on this, detailed embodiments and comparative examples are provided below to further illustrate the present invention.

[0145] The main sources of raw materials in the following examples and comparative examples are explained below:

[0146] PET resin, brand: DuPont, USA, purchased from Shanghai Huzi Plastic Raw Materials Co., Ltd.

[0147] N,N'-Ethylenebisstearamide, Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0148] Halloysite nanotubes, manufactured by Angxing New Carbon Materials Changzhou Co., Ltd., have an outer diameter of approximately 50 nm, an inner diameter of approximately 15 nm, and a length of approximately 1 μm.

[0149] 3-Aminopropyltriethoxysilane (APTS), Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0150] Antioxidant B215, brand: BASF, purchased from Shanghai Kaishengli Chemical Co., Ltd.;

[0151] Graphene oxide, thickness 0.6-1.2nm, diameter 0.8-2um, Guangzhou Hongwu Materials Technology Co., Ltd.

[0152] Vinyltriethoxysilane, Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0153] Sodium dodecylbenzenesulfonate, Nantong Runfeng Petrochemical Co., Ltd.;

[0154] Styrene, Shanghai Hongzhuang Chemical Technology Co., Ltd.;

[0155] Glycidyl methacrylate, Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0156] Acrylonitrile, Shanghai Jizhi Biochemical Technology Co., Ltd.;

[0157] Azobisisobutyronitrile (AIBN), Nantong Runfeng Petrochemical Co., Ltd.

[0158] Example 1: A heat-resistant and aging-resistant composite current collector base film is prepared by melt extrusion and stretching of the following raw materials in parts by weight: 100 parts of PET resin, 15 parts of multi-component composite reinforcing filler, and 1.8 parts of lubricant (N,N'-ethylene bis-stearamide).

[0159] The preparation process of this heat-resistant and aging-resistant composite current collector base film includes the following steps:

[0160] PET resin, multi-component composite reinforcing filler, and lubricant are mixed in proportion by weight, stirred at 90°C for 30 minutes, and the resulting mixture is added to a twin-screw extruder, melt-extruded at 260°C, cooled, and cast into sheets.

[0161] The cast sheet was preheated at 80℃ and then longitudinally stretched at 105℃ with a stretching ratio of 3.2 times; then it was transversely stretched at 110℃ with a stretching ratio of 4.0 times; after cooling, a heat-resistant and aging-resistant composite current collector base film was obtained.

[0162] In this example, the multi-component composite reinforced filler is prepared through the following steps:

[0163] S1. Preparation of functionalized halloysite nanotube-alumina composite particles:

[0164] S1-1, Preparation of aminated mesoporous alumina:

[0165] S1-1-1 Preparation of mesoporous alumina: Add 2g aluminum nitrate and 5g glucose to 50mL of deionized water, stir for 5min, adjust pH to 10 with sodium hydroxide, react under ultrasound for 2h, transfer the product to a reaction vessel, react at 190℃ for 10h, cool to room temperature, wash the product with deionized water, dry at 120℃ for 4h, then calcine at 900℃ for 2h, cool, grind, and obtain mesoporous alumina;

[0166] S1-1-2, Aminoation treatment: 1g of mesoporous alumina was added to 60mL of ethanol and ultrasonically dispersed for 60min. 0.4g of 3-aminopropyltriethoxysilane was added under stirring. The mixture was stirred and refluxed at 70℃ for 8h. After centrifugation, the precipitate was washed with ethanol and vacuum dried at 90℃ for 10h to obtain aminated mesoporous alumina.

[0167] S1-2, Combining halloysite nanotubes with aminated mesoporous alumina:

[0168] S1-2-1. Pore Enlargement Treatment of Halloysite Nanotubes: Halloysite nanotubes, sodium chloride, and sulfuric acid were added to deionized water. The concentration of sulfuric acid in the resulting mixture was controlled to be 2 mol / L, the concentration of halloysite nanotubes to be 10 mg / mL, and the concentration of sodium chloride to be 3 mg / mL. The mixture was ultrasonically treated at 60℃ for 7 h, centrifuged, and the precipitate was washed with deionized water until neutral. The precipitate was then vacuum dried at 100℃ for 12 h to complete the pore expansion treatment.

[0169] S1-2-2. Add 2g of halloysite nanotubes after pore-expanding treatment, 0.7g of cerium chloride, and 1.2g of aminated mesoporous alumina to 180mL of deionized water and ultrasonically disperse for 1h. Then add 0.15g of urea and stir for 30min. Transfer the resulting mixture to a reaction vessel and react at 180℃ for 16h. Cool to room temperature, centrifuge, wash the precipitate with deionized water, and vacuum dry at 100℃ for 12h to obtain halloysite nanotube-alumina composite particles.

[0170] S1-3, Surface modification: 1g halloysite nanotube-alumina composite particles were added to a mixture of 100mL deionized water and ethanol in a volume ratio of 1:5, ultrasonically dispersed for 45min, and 0.35g vinyltriethoxysilane was added under stirring. The mixture was stirred and refluxed at 70℃ for 8h, centrifuged, the precipitate was washed with ethanol, and vacuum dried at 80℃ for 10h to obtain modified halloysite nanotube-alumina composite particles.

[0171] S1-4, Antioxidant loading: Take 2g of modified halloysite nanotube-alumina composite particles and add them to 100mL of a 5% toluene solution of antioxidant B215. Disperse by ultrasonication for 1h, then shake in a shaker at 60℃ for 12h. Filter, wash the precipitate with ethanol, and vacuum dry at 80℃ for 12h to obtain functionalized halloysite nanotube-alumina composite particles.

[0172] S2. Preparation of modified graphene oxide:

[0173] S2-1. Purification treatment: Add 5g of graphene oxide to 150mL of mixed acid composed of 65wt% concentrated nitric acid and 20wt% hydrogen peroxide in a volume ratio of 2:1. Sonicate at 70℃ for 4h, filter, wash the precipitate with deionized water until neutral, and vacuum dry at 100℃ for 12h to obtain purified graphene oxide.

[0174] S2-2, Deposited magnesium oxide:

[0175] 1g of purified graphene oxide, 0.75g of magnesium chloride, and 0.25g of polyethylene glycol were added to 100mL of deionized water and ultrasonically dispersed for 45min. The pH was adjusted to 9 with 20wt% ammonia and reacted at 60℃ for 3h. The mixture was then filtered, washed with deionized water, dried at 90℃ for 8h, and then calcined at 600℃ for 2h to obtain the graphene oxide-magnesium oxide composite.

[0176] S2-3, Surface modification:

[0177] 1 g of graphene oxide-magnesium oxide composite was added to a mixture of 75 mL of deionized water and ethanol in a volume ratio of 1:5, and ultrasonically dispersed for 45 min. 0.25 g of vinyltriethoxysilane was added under stirring, and the mixture was stirred and refluxed at 70 °C for 8 h. After centrifugation, the precipitate was washed with ethanol and vacuum dried at 80 °C for 10 h to obtain the modified graphene oxide-magnesium oxide composite.

[0178] S3. A multi-component composite reinforcing filler was prepared by blending halloysite nanotube-alumina composite particles with modified graphene oxide:

[0179] S3-1. Mix 3.5g halloysite nanotube-alumina composite particles, 1.5g modified graphene oxide-magnesium oxide composite, and 1.2g sodium dodecylbenzenesulfonate and add them to 120mL toluene. Disperse the mixture by ultrasonication for 1.5h to obtain a mixed particle dispersion.

[0180] S3-2. Add 11g styrene, 5g glycidyl methacrylate, 4g acrylonitrile, and 0.4g azobisisobutyronitrile to 100mL toluene. Stir under nitrogen for 30min, then add the mixed particle dispersion. Continue stirring under nitrogen for 60min, raise the temperature to 80℃, and stir under nitrogen atmosphere for 8h. Cool to room temperature, wash the product with toluene and ethanol sequentially, and dry under vacuum at 90℃ for 12h to obtain the multi-component composite reinforcing filler.

[0181] Example 2 The only difference between this example and Example 1 is that the amount of aminated mesoporous alumina added in step S1-2-2 is changed to 0.6g.

[0182] Example 3 The only difference between this example and Example 1 is that the amount of aminated mesoporous alumina added in step S1-2-2 is changed to 1.8g.

[0183] Example 4: A heat-resistant and aging-resistant composite current collector base film is prepared by melt extrusion and stretching of the following raw materials in parts by weight: 100 parts of PET resin, 15 parts of multi-component composite reinforcing filler, and 2.0 parts of lubricant (N,N'-ethylene bis-stearamide).

[0184] The preparation process of this heat-resistant and aging-resistant composite current collector base film includes the following steps:

[0185] PET resin, multi-component composite reinforcing filler, and lubricant are mixed in proportion by weight, stirred at 80°C for 45 minutes, and the resulting mixture is added to a twin-screw extruder, melt-extruded at 255°C, cooled, and cast into sheets.

[0186] The cast sheet was preheated at 85°C and then longitudinally stretched at 100°C with a stretching ratio of 3.2 times; then transversely stretched at 105°C with a stretching ratio of 4.0 times; and cooled to obtain a heat-resistant and aging-resistant composite current collector base film.

[0187] In this example, the multi-component composite reinforced filler is prepared through the following steps:

[0188] S1. Preparation of functionalized halloysite nanotube-alumina composite particles:

[0189] S1-1. Preparation of aminated mesoporous alumina, the specific steps are the same as in Example 1;

[0190] S1-2, Combining halloysite nanotubes with aminated mesoporous alumina:

[0191] S1-2-1. Hollowite nanotube pore-expanding treatment, the specific steps are the same as in Example 1;

[0192] S1-2-2. Add 2g of halloysite nanotubes after pore-expanding treatment, 0.7g of cerium chloride, and 1.2g of aminated mesoporous alumina to 200mL of deionized water and ultrasonically disperse for 1h. Then add 0.17g of urea and stir for 30min. Transfer the resulting mixture to a reaction vessel and react at 180℃ for 16h. Cool to room temperature, centrifuge, wash the precipitate with deionized water, and vacuum dry at 100℃ for 12h to obtain halloysite nanotube-alumina composite particles.

[0193] S1-3, Surface modification: 1g halloysite nanotube-alumina composite particles were added to a mixture of 100mL deionized water and ethanol in a volume ratio of 1:5, ultrasonically dispersed for 45min, and 0.35g vinyltriethoxysilane was added under stirring. The mixture was stirred and refluxed at 75℃ for 7h, centrifuged, the precipitate was washed with ethanol, and vacuum dried at 80℃ for 10h to obtain modified halloysite nanotube-alumina composite particles.

[0194] S1-4, Antioxidant loading: Take 2g of modified halloysite nanotube-alumina composite particles and add them to 100mL of a 5% toluene solution of antioxidant B215. Disperse by ultrasonication for 1h, then shake in a shaker at 60℃ for 12h. Filter, wash the precipitate with ethanol, and vacuum dry at 80℃ for 12h to obtain functionalized halloysite nanotube-alumina composite particles.

[0195] S2. Prepare modified graphene oxide, the specific steps are the same as in Example 1;

[0196] S3. A multi-component composite reinforcing filler was prepared by blending halloysite nanotube-alumina composite particles with modified graphene oxide:

[0197] S3-1. Mix 3.5g halloysite nanotube-alumina composite particles, 1.5g modified graphene oxide-magnesium oxide composite, and 1.2g sodium dodecylbenzenesulfonate and add them to 120mL toluene. Disperse the mixture by ultrasonication for 1.5h to obtain a mixed particle dispersion.

[0198] S3-2. 11g styrene, 4.5g glycidyl methacrylate, 4.5g acrylonitrile, and 0.4g azobisisobutyronitrile were added to 100mL toluene. After stirring under nitrogen for 30min, the mixed particle dispersion was added, and stirring under nitrogen for another 60min was continued. The temperature was raised to 75℃, and the reaction was carried out under nitrogen atmosphere for 10h. After cooling to room temperature, the product was washed with toluene and ethanol in sequence, and dried under vacuum at 90℃ for 12h to obtain the multi-component composite reinforcing filler.

[0199] Example 5 The only difference between this example and Example 1 is that the raw materials for preparing the heat-resistant and aging-resistant composite current collector base film in this example include, by weight, 100 parts of PET resin, 13 parts of multi-component composite reinforcing filler, and 1.6 parts of lubricant (N,N'-ethylene bis-stearamide).

[0200] Comparative Example 1: The only difference between this example and Example 1 is that the raw materials for preparing the heat-resistant and aging-resistant composite current collector base film in this example include, by weight, 100 parts of PET resin, 1.6 parts of lubricant (N,N'-ethylene bis-stearamide), and 1.5 parts of antioxidant B215.

[0201] Comparative Example 2: The only difference between this example and Example 1 is that the multi-component composite reinforcing filler in this example is prepared through the following steps:

[0202] S1. Preparation of functionalized halloysite nanotube composite particles:

[0203] S1-2, Halloysite nanotube pore expansion treatment: Halloysite nanotubes, sodium chloride, and sulfuric acid were added to deionized water. The concentration of sulfuric acid in the resulting mixture was controlled to be 2 mol / L, the concentration of halloysite nanotubes to be 10 mg / mL, and the concentration of sodium chloride to be 3 mg / mL. The mixture was ultrasonically treated at 60℃ for 7 h, centrifuged, and the precipitate was washed with deionized water until neutral. The precipitate was then vacuum dried at 100℃ for 12 h to complete the pore expansion treatment.

[0204] S1-2. Add 2g of halloysite nanotubes after pore-expanding treatment and 0.7g of cerium chloride to 180mL of deionized water, and sonicate for 1h. Then add 0.15g of urea and stir for 30min. Transfer the resulting mixture to a reaction vessel and react at 180℃ for 16h. Cool to room temperature, centrifuge, wash the precipitate with deionized water, and vacuum dry at 100℃ for 12h to obtain halloysite nanotube composite particles.

[0205] S1-3, Surface modification: 1g halloysite nanotube composite particles were added to a mixture of 100mL deionized water and ethanol in a volume ratio of 1:5, and ultrasonically dispersed for 45min. 0.35g vinyltriethoxysilane was added under stirring, and the mixture was stirred and refluxed at 70℃ for 8h. After centrifugation, the precipitate was washed with ethanol and vacuum dried at 80℃ for 10h to obtain modified halloysite nanotube composite particles.

[0206] S1-4, Antioxidant loading: Take 2g of modified halloysite nanotube-alumina composite particles and add them to 100mL of toluene solution with a concentration of 5% antioxidant B215. Disperse by ultrasonication for 1h, then shake in a shaker at 60℃ for 12h. Filter, wash the precipitate with ethanol, and vacuum dry at 80℃ for 12h to obtain functionalized halloysite nanotube composite particles.

[0207] S2. Prepare modified graphene oxide, the specific steps are the same as in Example 1;

[0208] S3. Halloysite nanotube composite particles were blended with modified graphene oxide to prepare a multi-component composite reinforcing filler:

[0209] S3-1. Mix 3.5g halloysite nanotube composite particles, 1.5g modified graphene oxide-magnesium oxide composite, and 1.2g sodium dodecylbenzenesulfonate and add them to 120mL toluene. Disperse the mixture by ultrasonication for 1.5h to obtain a mixed particle dispersion.

[0210] S3-2. Add 11g styrene, 5g glycidyl methacrylate, 4g acrylonitrile, and 0.4g azobisisobutyronitrile to 100mL toluene. Stir under nitrogen for 30min, then add the mixed particle dispersion. Continue stirring under nitrogen for 60min, raise the temperature to 80℃, and stir under nitrogen atmosphere for 8h. Cool to room temperature, wash the product with toluene and ethanol sequentially, and dry under vacuum at 90℃ for 12h to obtain the multi-component composite reinforcing filler.

[0211] Comparative Example 3: The only difference between this example and Example 1 is that cerium chloride is not added in step S1-2-2, and the halloysite nanotube-alumina composite particles prepared are a mixture of halloysite nanotubes and aminated mesoporous alumina.

[0212] The only difference between Comparative Example 4 and Example 1 is that the multi-component composite reinforcing filler in this example is prepared through the following steps:

[0213] S1. Prepare functionalized halloysite nanotube-alumina composite particles, the specific steps are the same as in Example 1;

[0214] S2. Modify halloysite nanotube-alumina composite particles to prepare multi-component composite reinforcing fillers:

[0215] S2-1. Mix 5.0g halloysite nanotube-alumina composite particles and 1.2g sodium dodecylbenzenesulfonate and add them to 120mL toluene. Disperse the mixture by ultrasonication for 1.5h to obtain a particle dispersion.

[0216] S2-2. 11g styrene, 5g glycidyl methacrylate, 4g acrylonitrile, and 0.4g azobisisobutyronitrile were added to 100mL toluene. After stirring under nitrogen for 30min, the particle dispersion was added, and stirring under nitrogen for another 60min was continued. The temperature was raised to 80℃, and the reaction was carried out under nitrogen atmosphere for 8h. After cooling to room temperature, the product was washed with toluene and ethanol in sequence, and dried under vacuum at 90℃ for 12h to obtain the multi-component composite reinforced filler.

[0217] The only difference between Comparative Example 5 and Example 1 is that the multi-component composite reinforcing filler in this example is prepared through the following steps:

[0218] S1. Prepare functionalized halloysite nanotube-alumina composite particles, the specific steps are the same as in Example 1;

[0219] S2. Preparation of modified graphene oxide:

[0220] S2-1. Purification treatment, the specific steps are the same as in Example 1;

[0221] S2-2, Surface modification:

[0222] 1g of purified graphene oxide was added to a mixture of 75mL of deionized water and ethanol in a volume ratio of 1:5, and ultrasonically dispersed for 45min. 0.25g of vinyltriethoxysilane was added under stirring, and the mixture was stirred and refluxed at 70℃ for 8h. After centrifugation, the precipitate was washed with ethanol and vacuum dried at 80℃ for 10h to obtain modified graphene oxide.

[0223] S3. Halloysite nanotube-alumina composite particles are blended and modified with modified graphene oxide to prepare a multi-component composite reinforcing filler. The specific steps are the same as in Example 1.

[0224] The only difference between Comparative Example 6 and Example 1 is that:

[0225] Step S3 in this example is as follows:

[0226] 3.5g halloysite nanotube-alumina composite particles, 1.5g modified graphene oxide-magnesium oxide composite, and 1.2g sodium dodecylbenzenesulfonate were mixed and added to 120mL toluene. The mixture was ultrasonically dispersed for 1.5h to obtain a mixed particle dispersion. After centrifugation, the precipitate was washed with toluene and ethanol in sequence and then vacuum dried at 90℃ for 12h to obtain a multi-component composite reinforced filler.

[0227] Performance testing

[0228] I. Relevant performance tests of the intermediate product prepared in Example 1

[0229] 1. Reference Figure 1 The image shows the infrared absorption spectra of the aminated mesoporous alumina (SM-Al2O3) and modified halloysite nanotube-alumina composite particles (HNTs@SM-Al2O3) prepared in Example 1, illustrating the successful modification of the mesoporous alumina surface with amino groups and the successful composite of halloysite nanotubes and aminated mesoporous alumina. (Refer to...) Figure 2 The image shown is the XRD pattern of the graphene oxide-magnesium oxide composite prepared in Example 1, which demonstrates the successful deposition of magnesium oxide on graphene oxide.

[0230] 2. The mesoporous parameters of the mesoporous alumina and aminated mesoporous alumina prepared in Example 1 were measured (obtained by nitrogen adsorption-desorption method combined with BET equation theory calculation). The test results are shown in Table 1 below:

[0231] Table 1

[0232]

[0233] SEM image analysis showed that before the pore-expansion treatment, the halloysite nanotubes had an outer diameter of about 50 nanometers, an inner diameter of about 15 nanometers, and a length of about 1 micrometer. After the pore-expansion treatment, the inner diameter of the halloysite nanotubes was about 24 nm.

[0234] 3. Test of sustained-release performance of intermediate products

[0235] Test method: Add 100 mL of toluene to a flask, then add 2 g of functionalized halloysite nanotube-alumina composite particles, stir for 30 min, seal, open the lid and stir every 6 h or 12 h to detect the concentration of antioxidant B215 in the mixed solution, calculate the cumulative release percentage of antioxidant B215 at different release times (cumulative mass percentage of release amount to total load), and plot the release curve.

[0236] The amount of aminated mesoporous alumina added in step S1-2-2 of Example 1 was changed to 0g, 0.6g, 1.2g, and 1.8g, and the resulting functionalized halloysite nanotube-alumina composite particles were successively named B215@HNTs-Al-0, B215@HNTs-Al-0.6, B215@HNTs-Al-1.2, and B215@HNTs-Al-1.8; the release curves of each particle were obtained according to the above method.

[0237] Test results are as follows Figure 3 As shown, it can be seen that with the increase of the content of aminated mesoporous alumina in the functionalized halloysite nanotube-alumina composite particles, the slow release rate of antioxidant B215 gradually decreases, indicating that the slow release rate can be controlled by adjusting the content of aminated mesoporous alumina.

[0238] II. Base Film Related Performance Tests

[0239] 1. Tensile strength test

[0240] Referring to standard ASTM D882-12, "Standard Test Methods for Tensile Properties of Thin Films and Sheets," the tensile breaking strength of the composite current collector base films prepared in the examples and comparative examples was tested using a universal tensile testing machine. The test results are shown in Table 2 below.

[0241] Table 2

[0242]

[0243] The test results show that the composite current collector base film prepared in the examples has high tensile strength, while the comparative examples all showed a certain degree of decrease compared to Example 1. In Comparative Example 1, the absence of multi-component composite reinforcing filler led to a significant decrease in tensile strength. The results of Comparative Example 2 indicate that the aminated mesoporous alumina in the multi-component composite reinforcing filler can improve tensile strength. In Comparative Example 3, the lack of chemical composite formation of halloysite nanotubes and aminated mesoporous alumina with cerium chloride weakened the reinforcing effect of both, ultimately leading to a decrease in tensile strength. In Comparative Example 4, the absence of modified graphene oxide resulted in a decrease in tensile strength. The results of Comparative Example 5 indicate that magnesium oxide deposition on the graphene oxide surface can improve the tensile strength of the base film. The significant decrease in tensile strength in Comparative Example 6 is due to the failure of the halloysite nanotube-alumina composite particles and the modified graphene oxide-magnesium oxide composite to achieve good uniform dispersion in the PET resin when the polymer was not grafted.

[0244] 2. Heat and oxygen aging resistance test

[0245] Test Method: The composite current collector base films prepared in the examples and comparative examples were placed in an aging chamber and subjected to accelerated aging tests in hot air at 85°C for 120 hours and 360 hours, respectively. After cooling to room temperature, the longitudinal tensile strength was measured again. The retention rate of longitudinal tensile strength (tensile strength after aging / tensile strength before aging) was used to measure the heat aging resistance performance. The higher the value, the better the heat aging resistance. The test results are shown in Table 3 below:

[0246] Table 3

[0247]

[0248] According to the test results, in the early stage of aging (120 hours of aging), the tensile strength retention rate of Comparative Example 2, Example 2, Example 1, and Example 3 decreased sequentially (representing that the antioxidant performance weakened sequentially); in the later stage of aging (360 hours of aging), the tensile strength retention rate of Comparative Example 2, Example 2, Example 1, and Example 3 increased sequentially (representing that the antioxidant performance strengthened sequentially).

[0249] Analysis of the test results showed that when the content of aminated mesoporous alumina in the functionalized halloysite nanotube-alumina composite particles increased (the content of aminated mesoporous alumina in Comparative Example 2, Example 2, Example 1, and Example 3 increased sequentially), the slow-release rate of the antioxidant decreased, and the concentration of antioxidant that could be provided in the early stage of aging decreased. Therefore, the antioxidant performance decreased in the early stage of aging, which was reflected in a lower tensile strength retention rate. However, as the aging time increased, the antioxidant was gradually consumed, and with a relatively lower slow-release rate, the anti-aging effect provided in the later stage of aging was stronger, which was reflected in a higher tensile strength retention rate. That is, as the aging time increased, the degree of decline in anti-aging performance decreased, indicating that the anti-aging effect lasted longer.

[0250] In Comparative Example 1, no multi-component composite reinforcing filler was added, and the antioxidant was directly blended with the PET resin, thus lacking the sustained-release effect of the antioxidant. This resulted in significantly inferior anti-aging performance compared to Example 1, and the anti-aging effect decreased markedly with prolonged aging time. In Comparative Example 6, the failure to achieve uniform dispersion of halloysite nanotube-alumina composite particles and modified graphene oxide-magnesium oxide composite in the PET resin hindered the full utilization of their reinforcing properties, leading to a significant decrease in anti-aging performance.

[0251] 3. Heat shrinkage rate test

[0252] The thermal shrinkage rate of the composite current collector base film prepared according to the ASTM D2732 test examples and comparative examples at 150°C is shown in Table 4 below.

[0253] Table 4

[0254]

[0255] The test results show that the base films of Examples 1-5 have excellent heat resistance, while the heat resistance of Comparative Examples 1-6 decreased to varying degrees.

[0256] III. Application Performance Testing

[0257] A copper layer with a thickness of 0.85 μm was electroplated onto the upper and lower surfaces of the composite current collector substrate film prepared in the examples and comparative examples using an electroplating process to prepare the composite current collector. The specific process was as follows: the substrate film was placed in an electroplating solution and electroplated at a temperature of 25°C and a current intensity of 2A. During the electroplating process, air was continuously introduced into the electroplating solution. The electroplating solution contained 160 g / L copper sulfate, 120 g / L sulfuric acid, and 40 mg / L hydrochloric acid. The composite current collector was then subjected to an adhesion test using the cross-cut adhesion test method as described in standard GB9286-2021. The test film was divided into 400 1x1 mm squares, and then the film was tightly adhered with 3M tape. The tape was then peeled off vertically, and the detachment of the copper layer in each square was observed. The cross-cut adhesion rate was calculated. Three sets of tests were performed for each sample, and the average value was taken as the result. The lower the adhesion rate, the stronger the adhesion. The test results are shown in Table 5 below.

[0258] Table 5

[0259]

[0260] The test results show that the base film prepared in Examples 1-5 has good bonding strength with the copper layer, while Comparative Examples 1-6 show varying degrees of decrease.

[0261] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for the present invention. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, the present invention is not limited to the specific details.

Claims

1. A heat-resistant and aging-resistant composite current collector base film, characterized in that, It is prepared by melt extrusion and stretching of the following raw materials in parts by weight: 100 parts PET resin, 12-25 parts multi-component composite reinforcing filler, and 0.5-3 parts lubricant; The multi-component composite reinforced filler is prepared by the following steps: S1. Preparation of functionalized halloysite nanotube-alumina composite particles: S1-1. Mesoporous alumina and 3-aminopropyltriethoxysilane are mixed in ethanol, heated and stirred to react, and aminated mesoporous alumina is obtained. S1-2. Halloysite nanotubes, sodium chloride, and sulfuric acid are added to deionized water and heated under ultrasonic conditions to expand the pores. Halloysite nanotubes after pore-expanding treatment, cerium chloride, and aminated mesoporous alumina were dispersed in deionized water, and then urea was added. The resulting mixture was transferred to a reaction vessel and reacted under heating. After the reaction was completed, the solid product was separated to obtain halloysite nanotube-alumina composite particles. S1-3. The surface of halloysite nanotube-alumina composite particles was modified with vinyltriethoxysilane to obtain modified halloysite nanotube-alumina composite particles. S1-4, Antioxidant loading: Modified halloysite nanotube-alumina composite particles were added to an antioxidant solution, ultrasonically dispersed, and then shaken on a shaker under heating. After the reaction was completed, the solid product was separated to obtain functionalized halloysite nanotube-alumina composite particles. S2. Preparation of modified graphene oxide: S2-1, Deposition of magnesium oxide: Graphene oxide, magnesium chloride, and polyethylene glycol are added to deionized water, ultrasonically dispersed, pH adjusted to alkaline, heated to react, filtered after the reaction is completed, and the solid product is calcined to obtain a graphene oxide-magnesium oxide composite. S2-2. The surface of the graphene oxide-magnesium oxide composite was modified with vinyltriethoxysilane to obtain the modified graphene oxide-magnesium oxide composite. S3. Preparation of multi-component composite reinforced fillers: S3-1. Halloysite nanotube-alumina composite particles, modified graphene oxide-magnesium oxide composite, and sodium dodecylbenzenesulfonate are mixed and dispersed in toluene to obtain a mixed particle dispersion. S3-2. Styrene, glycidyl methacrylate, acrylonitrile, and azobisisobutyronitrile are added to toluene, and after stirring with nitrogen, the mixed particle dispersion is added. Nitrogen is then continued to be purged and stirred, and the mixture is heated to react. After the reaction is completed, the solid product is separated to obtain the multi-component composite reinforcing filler.

2. The heat-resistant and aging-resistant composite current collector substrate film according to claim 1, characterized in that, The average pore size of mesoporous alumina is smaller than the inner diameter of halloysite nanotubes.

3. The heat-resistant and aging-resistant composite current collector substrate film according to claim 1, characterized in that, The average pore size of mesoporous alumina is 2-10 nm, while the inner diameter of halloysite nanotubes is 10-20 nm.

4. The heat-resistant and aging-resistant composite current collector base film according to claim 1, characterized in that, The antioxidant is selected from at least one of antioxidant B215, antioxidant 168, antioxidant 330, 1076, antioxidant 626, antioxidant 618, and antioxidant PL-440.

5. The heat-resistant and aging-resistant composite current collector base film according to claim 1, characterized in that, The multi-component composite reinforced filler is prepared by the following steps: S1. Preparation of functionalized halloysite nanotube-alumina composite particles: S1-1. Mesoporous alumina is dispersed in ethanol, and 3-aminopropyltriethoxysilane is added under stirring. The mixture is heated and refluxed under stirring to separate the solid product and obtain aminated mesoporous alumina. S1-2. Halloysite nanotubes, sodium chloride, and sulfuric acid are added to deionized water and ultrasonically treated under heating to expand the pores. Halloysite nanotubes after pore-expanding treatment, cerium chloride, and aminated mesoporous alumina were added to deionized water, ultrasonically dispersed, then urea was added and stirred. The resulting mixture was transferred to a reaction vessel and reacted under heating. After the reaction was completed, the solid product was separated to obtain halloysite nanotube-alumina composite particles. S1-3, Surface modification: Halloysite nanotube-alumina composite particles were added to a mixture of deionized water and ethanol, ultrasonically dispersed, vinyltriethoxysilane was added under stirring, and the mixture was heated and stirred under reflux. After the reaction was completed, the solid product was separated to obtain modified halloysite nanotube-alumina composite particles. S1-4, Antioxidant loading: Modified halloysite nanotube-alumina composite particles were added to a toluene solution of antioxidant B215, ultrasonically dispersed, and then shaken on a shaker under heating. After the reaction was completed, the solid product was separated to obtain functionalized halloysite nanotube-alumina composite particles. S2. Preparation of modified graphene oxide: S2-1, Deposition of magnesium oxide: Graphene oxide, magnesium chloride, and polyethylene glycol are added to deionized water, ultrasonically dispersed, pH adjusted to alkaline, heated to react, filtered after the reaction is completed, and the solid product is calcined to obtain a graphene oxide-magnesium oxide composite. S2-2, Surface modification: The graphene oxide-magnesium oxide composite was added to a mixture of deionized water and ethanol, ultrasonically dispersed, and vinyltriethoxysilane was added under stirring. The mixture was heated and stirred under reflux. After the reaction was completed, the solid product was separated to obtain the modified graphene oxide-magnesium oxide composite. S3. Preparation of multi-component composite reinforced fillers: S3-1. Halloysite nanotube-alumina composite particles, modified graphene oxide-magnesium oxide composite, and sodium dodecylbenzenesulfonate were mixed and added to toluene, and ultrasonically dispersed to obtain a mixed particle dispersion. S3-2. Styrene, glycidyl methacrylate, acrylonitrile, and azobisisobutyronitrile were added to toluene, and after stirring with nitrogen gas, the mixed particle dispersion was added. Nitrogen gas was continued to be purged and stirred, and the temperature was increased. The reaction was stirred under a nitrogen atmosphere. After the reaction was completed, the solid product was separated to obtain the multi-component composite reinforcing filler.

6. The heat-resistant and aging-resistant composite current collector base film according to claim 5, characterized in that, Step S1 is as follows: S1-1. Add 0.5-2 g of mesoporous alumina to 30-120 mL of ethanol, ultrasonically disperse for 30-120 min, add 0.2-0.8 g of 3-aminopropyltriethoxysilane while stirring, stir and reflux at 65-80 °C for 4-12 h, centrifuge, wash the precipitate with ethanol, and vacuum dry at 80-100 °C for 5-20 h to obtain aminated mesoporous alumina. S1-2. Add halloysite nanotubes, sodium chloride, and sulfuric acid to deionized water, and control the concentration of sulfuric acid in the resulting mixture to be 1-3 mol / L, the concentration of halloysite nanotubes to be 5-20 mg / mL, and the concentration of sodium chloride to be 1.5-6 mg / mL. Sonicate at 50-75℃ for 3-10 h, centrifuge, wash the precipitate with deionized water until neutral, and vacuum dry at 90-110℃ for 6-24 h to complete the pore expansion treatment. Add 1-4g of halloysite nanotubes after pore-expanding treatment, 0.35-1.4g of cerium chloride, and 0.6-2.4g of aminated mesoporous alumina to 90-360mL of deionized water and ultrasonically disperse for 0.5-2h. Then add 0.075-0.3g of urea and stir for 15-60min. Transfer the resulting mixture to a reaction vessel and react at 160-200℃ for 10-32h. Cool to room temperature, centrifuge, wash the precipitate with deionized water, and vacuum dry at 90-110℃ for 6-24h to obtain halloysite nanotube-alumina composite particles. S1-3, Surface modification: Add 0.5-2g halloysite nanotube-alumina composite particles to a mixture of 50-200mL deionized water and ethanol in a volume ratio of 1:5, ultrasonically disperse for 30-90min, add 0.15-0.7g vinyltriethoxysilane under stirring, stir and reflux at 60-80℃ for 4-16h, centrifuge, wash the precipitate with ethanol, and vacuum dry at 70-90℃ for 5-24h to obtain modified halloysite nanotube-alumina composite particles; S1-4, Antioxidant Loading: Take 1-4g of modified halloysite nanotube-alumina composite particles and add them to 50-200mL of a toluene solution containing 2-15% antioxidant B215. Disperse the particles ultrasonically for 0.5-2h, then shake them on a shaker at 50-70℃ for 6-24h. Filter the mixture, wash the precipitate with ethanol, and vacuum dry it at 70-90℃ for 6-24h to obtain functionalized halloysite nanotube-alumina composite particles.

7. The heat-resistant and aging-resistant composite current collector base film according to claim 5, characterized in that, Step S2 is as follows: S2-1, Deposition of magnesium oxide: Add 0.5-2g graphene oxide, 0.3-1.5g magnesium chloride, and 0.1-0.5g polyethylene glycol to 50-200mL of deionized water, sonicate for 30-90min, adjust the pH to 8-10 with 15-25wt% ammonia, react at 50-70℃ for 1.5-6h, filter, wash with deionized water, dry at 80-100℃ for 4-16h, and then calcine at 550-700℃ for 1-4h to obtain graphene oxide-magnesium oxide composite. S2-2, Surface modification: Add 0.5-2g of graphene oxide-magnesium oxide composite to a mixture of 30-150mL of deionized water and ethanol in a volume ratio of 1:5, and ultrasonically disperse for 30-90min. Add 0.15-0.5g of vinyltriethoxysilane while stirring, and reflux at 60-80℃ for 4-16h. Centrifuge, wash the precipitate with ethanol, and vacuum dry at 70-90℃ for 5-24h to obtain the modified graphene oxide-magnesium oxide composite.

8. The heat-resistant and aging-resistant composite current collector substrate film according to claim 5, characterized in that, Step S3 is as follows: S3-1. Mix 1.75-7g halloysite nanotube-alumina composite particles, 0.75-3g modified graphene oxide-magnesium oxide composite, and 0.6-2.4g sodium dodecylbenzenesulfonate and add them to 60-240mL toluene. Disperse the mixture by ultrasonication for 0.75-3h to obtain a mixed particle dispersion. S3-2. Add 5.5-22g styrene, 2.5-10g glycidyl methacrylate, 2-8g acrylonitrile, and 0.2-0.8g azobisisobutyronitrile to 50-200mL of toluene. Stir under nitrogen for 15-60min, then add the mixed particle dispersion. Continue stirring under nitrogen for 30-120min. Heat to 75-85℃ and react under nitrogen atmosphere for 4-16h. Cool to room temperature, wash the product with toluene and ethanol sequentially, and vacuum dry at 70-95℃ for 6-24h to obtain the multi-component composite reinforced filler.

9. A preparation process for a heat-resistant and aging-resistant composite current collector substrate film as described in any one of claims 1-8, characterized in that, Includes the following steps: PET resin, multi-component composite reinforcing filler, and lubricant are mixed evenly according to the weight ratio. The resulting mixture is melt-extruded at 250-260℃, cooled, and cast into sheets. After preheating, the cast sheets are stretched longitudinally and then stretched transversely to obtain a heat-resistant and aging-resistant composite current collector base film.

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