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WO-2026091241-A1 - MODIFIED CURRENT COLLECTOR, PREPARATION METHOD THEREFOR, AND LITHIUM ION BATTERY

WO2026091241A1WO 2026091241 A1WO2026091241 A1WO 2026091241A1WO-2026091241-A1

Abstract

The present application provides a modified current collector, a preparation method therefor, and a lithium ion battery. The modified current collector comprises a first functionally modified coating layer, a first nano-carbon coating layer, a current collector, a second nano-carbon coating layer, and a second functionally modified coating layer sequentially arranged in a stacked configuration; the first nano-carbon coating layer and the second nano-carbon coating layer each independently comprise a nano-carbon coating material; and the first functionally modified coating layer and the second functionally modified coating layer each independently comprise a nano-carbon coating material and a functionalized modification material. The described modified current collector not only enhances the conductive network between an active material and the current collector, but also increases ion transport capacity, thereby reducing polarization resistance and inhibiting DCR increases in lithium-ion batteries during charging and discharging cycles, and thus improving rate performance and cycle life in lithium-ion batteries. In addition, the modified current collector having the above structure has high porosity, thereby helping to improve wettability of the modified current collector in an electrolyte.

Inventors

  • LIU, HANG
  • HU, QI
  • WANG, CHAO
  • LIU, Ziwen
  • HE, WEI
  • LIU, JINCHENG

Assignees

  • 惠州亿纬动力电池有限公司
  • 湖北亿纬动力有限公司

Dates

Publication Date
20260507
Application Date
20241210
Priority Date
20241029

Claims (20)

  1. A modified current collector, characterized in that the modified current collector comprises a first functional modified coating, a first nano-carbon coating, a current collector, a second nano-carbon coating, and a second functional modified coating, which are sequentially stacked. The first nano-carbon coating and the second nano-carbon coating each independently comprise nano-carbon coating materials; The first functional modified coating and the second functional modified coating each independently comprise a nano-carbon coating material and a functionalized modified material.
  2. The modified current collector according to claim 1, characterized in that the tortuosity ratio of the modified current collector is... , in, The bending factor of the first or second nano-carbon coating. The bending factor of the first functionally modified coating or the second functionally modified coating; The tortuosity factor of the modified current collector is 5-90%; And/or, the electronic conductivity ratio of the modified current collector is , in, The electronic conductivity of the first or second nano-carbon coating is given. The electronic conductivity of the first functionally modified coating or the second functionally modified coating; The electronic conductivity ratio of the modified current collector is 2-85%.
  3. According to claim 2, the modified current collector is characterized in that the bending factor ratio of the modified current collector is 10~80%.
  4. According to claim 2, the modified current collector is characterized in that the electronic conductivity ratio of the modified current collector is 5-80%.
  5. The modified current collector according to any one of claims 1 to 4 is characterized in that the mass content of the functionalized modified material in the first functional modified coating is 0.05~50%; and/or, the functionalized modified material is selected from any one or more of transition metal oxide nanowires, transition metal oxide nanofibers, conductive polymer nanowires, conductive polymer nanofibers, MXene and MOFs.
  6. The modified current collector according to any one of claims 1 to 4 is characterized in that the mass content of the functionalized modified material in the second functional modified coating is 0.05~50%.
  7. The modified current collector according to any one of claims 1 to 4 is characterized in that the nano-carbon coating material is selected from any one or more of conductive graphite, carbon black, graphene, carbon nanotubes and VGCF.
  8. According to claim 5, the modified current collector is characterized in that the transition metal oxide nanowires and the transition metal oxide nanofibers are each independently selected from any one or more of RuO2 , MnO2 , V2O5 , NiO2 and their corresponding derivatives.
  9. According to claim 5, the modified current collector is characterized in that the conductive polymer nanowires and the conductive polymer nanofibers are each independently selected from any one or more of polyaniline, polypyrrole, polythiophene and their corresponding derivatives.
  10. The modified current collector according to claim 5, characterized in that the MXene is selected from the group with the general chemical formula [missing information]. Two-dimensional layered materials derived from transition metal carbides, with the general chemical formula: Two-dimensional layered materials derived from transition metal nitrides, with the general chemical formula: The material is selected from any one or more two-dimensional layered materials derived from transition metal carbonitrides, wherein M is a transition metal element selected from any one or more of Ti, V, Cr, Zr, and Nb; and X is carbon and/or nitrogen. The surface group is selected from any one or more of hydroxyl, fluorine, and carbonyl groups, where 1 ≤ n ≤ 4.
  11. According to claim 5, the modified current collector is characterized in that the MOFs are porous materials composed of metal and organic ligands, the metal is a metal ion and/or a metal cluster, and the MOFs are selected from any one or more of network metal-organic framework materials, zeolite-like imidazolium ester framework materials, Levasil framework materials, and pore-channel framework materials.
  12. The modified current collector according to any one of claims 1 to 11 is characterized in that the thickness of the first nano-carbon coating and the second nano-carbon coating are each independently 0.5~80 μm; and/or, the width of the first nano-carbon coating and the second nano-carbon coating are each independently 50~1000 mm; and/or, the thickness of the first functional modified coating and the second functional modified coating are each independently 0.5~80 μm; and/or, the width of the first functional modified coating and the second functional modified coating are each independently 50~1000 mm; And/or, the thickness ratio of the first functional modified coating, the first nano-carbon coating, and the current collector is 10~60:10~60:10~15; And/or, the thickness ratio of the second functional modified coating, the second nano-carbon coating, and the current collector is 10~60:10~60:10~15; And/or, the thickness of the current collector is 6~16μm; The current collector is a copper foil or an aluminum foil; and/or, the aluminum foil has a thickness of 12-16 μm; and/or, the copper foil has a thickness of 6-12 μm; and/or, the modified current collector has a porosity of 20-80%.
  13. The modified current collector according to claim 12 is characterized in that the porosity of the modified current collector is 40-80%.
  14. A method for preparing the modified current collector according to any one of claims 1 to 13, characterized in that the preparation method comprises: Step S1: The raw materials including nano-carbon coating material, first dispersant, first organic solvent and first binder are first mixed to obtain nano-carbon coating slurry; Step S2 involves mixing the raw materials, including nano-carbon coating material, functionalized modified material, second dispersant, second organic solvent, and second binder, to obtain a functionalized modified coating slurry. Step S3: Coat the two opposite surfaces of the current collector with the nano-carbon coating slurry to form a first nano-carbon coating and a second nano-carbon coating. Step S4: The functionally modified coating slurry is coated on the surfaces of the first nano-carbon coating and the second nano-carbon coating away from the current collector, respectively, to form the first functionally modified coating and the second functionally modified coating, thus obtaining the modified current collector.
  15. According to the preparation method of claim 14, step S1 further includes: Step S11: The nano-carbon coating material, the first dispersant, and the first organic solvent are first dispersed to obtain a first conductive slurry; Step S12: Mix the first conductive paste and the first adhesive to obtain the nano-carbon coating paste. Wherein, the mass ratio of the nano-carbon coating material, the first dispersant and the first organic solvent is 1:0.01~0.5:2~50; and/or, the viscosity of the nano-carbon coating slurry is 800~10000 mPa·s; And/or, the first dispersion rotation speed is 20~10000 rpm, and/or, the first dispersion time is 0.5~1.5 h, and/or, the first mixing time is 0.5~24 h; And/or, the first dispersant is selected from any one or more of anionic dispersants, cationic dispersants, nonionic dispersants, and electrically neutral dispersants; And/or, the first organic solvent is selected from any one or more of N-methylpyrrolidone, γ-butyrolactone, and dimethylformamide; And/or, the first adhesive is selected from any one or more of polyvinylidene fluoride, styrene-butadiene rubber, carboxymethyl cellulose, polyacrylic acid, and polyacrylonitrile.
  16. According to the preparation method of claim 15, the viscosity of the nano-carbon coating slurry is 850~9000 mPa·s.
  17. According to the preparation method of claim 15 or 16, step S2 further includes: Step S21: The nano-carbon coating material, the functionalized modified material, the second dispersant, and the second organic solvent are dispersed in a second manner to obtain a second conductive slurry; Step S22: The second conductive paste and the second adhesive are mixed in the second way to obtain the functional modified coating paste; Wherein, the mass ratio of the nano-carbon coating material, the functionalized modified material, the second dispersant and the second organic solvent is 1:0.01~0.95:0.01~0.5:2~50; and/or, the viscosity of the functionalized modified coating slurry is 1200~10000 mPa·s; And/or, the second dispersion rotation speed is 50~8000 rpm, and/or, the second dispersion time is 0.5~1.5 h, and/or, the second mixing time is 0.5~24 h; And/or, the second dispersant is selected from any one or more of anionic dispersants, cationic dispersants, nonionic dispersants, and electrically neutral dispersants; And/or, the second organic solvent is selected from any one or more of N-methylpyrrolidone, γ-butyrolactone, and dimethylformamide; And/or, the second adhesive is selected from any one or more of polyvinylidene fluoride, styrene-butadiene rubber, carboxymethyl cellulose, polyacrylic acid, and polyacrylonitrile.
  18. According to the preparation method of claim 17, the viscosity of the functional modified coating slurry is 1500~9500 mPa·s.
  19. The preparation method according to any one of claims 14 to 18 is characterized in that step S3 further includes cleaning the current collector before coating, wherein the cleaning agent used for cleaning is an acid solution, and the acid solution is selected from any one or more of 0.5-50 wt% acetic acid solution, 0.5-37 wt% hydrochloric acid solution and 0.5-45 wt% phosphoric acid solution; and/or, the pH value of the acid solution is 1-6.
  20. A lithium-ion battery, comprising a positive electrode, a negative electrode, a separator, and an electrolyte, characterized in that the positive electrode and/or the negative electrode comprises the modified current collector according to any one of claims 1 to 13.

Description

Modified current collectors and their preparation methods, lithium-ion batteries This application claims priority to Chinese Patent Application No. 202411527251.5, filed with the Chinese Patent Office on October 29, 2024, the entire contents of which are incorporated herein by reference. Technical Field This application relates to the field of current collector technology, specifically to a modified current collector and its preparation method, and lithium-ion batteries, and more particularly to the application of a modified current collector and its preparation method in the preparation of lithium-ion batteries. Background Technology With the rapid development of lithium-ion battery technology, higher requirements are now being placed on the power performance, rate performance, and cycle life of lithium-ion batteries. Phosphate-based power batteries, due to the inherently low electrical and electronic conductivity of their materials, are typically optimized through carbon coating. However, the contact between the current collector and the active material in lithium-ion batteries is also a crucial factor affecting charge and discharge performance. Therefore, modifying the current collector has become an effective method to improve lithium-ion battery performance. A common modification technique involves surface treatment using functional coatings. For example, uniformly coating dispersed nano-conductive graphite and carbon black particles onto aluminum or copper foil to prepare carbon-coated foil materials can reduce internal resistance and polarization, thereby improving the rate performance and cycle life of lithium-ion batteries. However, the low porosity of the functional coating hinders the diffusion rate of Li + in the electrode, thus reducing the rate performance and cycle life of the lithium-ion battery. Attached Figure Description The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings: Figure 1 shows a schematic diagram of the modified current collector of this application; The above figures include the following reference numerals: 1. First functional modified coating; 2. First nano-carbon coating; 3. Current collector; 4. Second nano-carbon coating; 5. Second functional modified coating; 6. Nano-carbon coating material; 7. Transition metal oxide nanowires and transition metal oxide nanofibers; 8. Conductive polymer nanowires and conductive polymer nanofibers; 9. MXene; 10. MOFs. To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application. In some embodiments of this application, the tortuosity ratio of the modified current collector is: ,in, The bending factor is the bending factor of the first or second nano-carbon coating. The bending factor is the first functional modified coating or the second functional modified coating; the bending factor ratio of the modified current collector is 5~90%, and in some embodiments of this application, the bending factor ratio of the modified current collector is 10~80%; and/or, the electronic conductivity ratio of the modified current collector is... ,in, The electronic conductivity of the first or second nano-carbon coating. The electronic conductivity of the first functional modified coating or the second functional modified coating; the electronic conductivity ratio of the modified current collector is 2~85%, and in some embodiments of this application, the electronic conductivity ratio of the modified current collector is 5~80%. Controlling the torsional coefficient of the modified current collector within the aforementioned range is beneficial for fully leveraging the synergistic effect between the first nano-carbon coating and the first functional modified coating (or the second nano-carbon coating and the second functional modified coating). This allows the modified current collector to maintain good conductivity even under bending or deformation conditions. Controlling the electronic conductivity ratio of the modified current collector within the aforementioned range helps to effectively transmit current and reduce internal polarization of the battery, thereby contributing to improved rate performance and cycle life of lithium-ion batteries. In some embodiments of this application, the mass content of the functionalized modified material in the first functional modified coating is 0.05-50%; and/or, the mass content of the functionalized modified material in the second functional modified coating is 0.05-50%; and/or, the nano-carbon coating