A method for preparing a composite current collector for a low-temperature lithium-ion battery capable of rapid discharge at low temperatures

Abstract

The present invention discloses a method for preparing a composite current collector for a low-lithium ion battery capable of rapid discharge at low temperature, the method comprising the following steps: step 1, preparing a porous polymer substrate; step 2, preparing a metal-based prepreg; step 3, preparing a porous composite metal current collector. The composite current collector prepared by this method has an intermediate layer composed of a porous polymer, and is plated with an aluminum metal layer or a copper layer on both sides, which are used for the positive electrode and the negative electrode respectively. This porous current collector replaces the traditional metal current collector and can absorb and store a certain amount of electrolyte, thereby providing an ion source on one side of the current collector, achieving ion-electron balance, and achieving the effect of high discharge capacity of the battery at low temperature and high current. The porous composite current collector prepared by the present invention is lighter than conventional metal current collectors, which is conducive to lightweight batteries and the realization of batteries with higher energy density. Because it has the ability to store electrolyte, it can alleviate the attenuation caused by electrolyte drying up and extend battery life.

Description

Technical Field

[0001] The present invention belongs to the technical field of lithium ion batteries and relates to a method for preparing a current collector, and in particular to a method for preparing a composite current collector for a low-lithium ion battery capable of rapid discharge at low temperature. Background Art

[0002] Lithium-ion batteries, due to their high specific energy, long cycle life, and lack of memory effect, have been widely used in battery-powered vehicles, portable electronic devices, and industrial and commercial energy storage. This system is considered one of the most promising electrochemical energy storage technologies, and its development and exploration in a wider range of application scenarios, such as deep space and cold regions, are attracting attention. These applications place high demands on the low-temperature discharge performance of lithium-ion batteries. Currently, commercial lithium-ion and sodium-ion secondary batteries are nearly incapable of discharge at temperatures below -40°C, especially at high rates. This limits their application in cold-climate energy storage, low-altitude drones, and intelligent devices. The conductivity of lithium-ion electrolytes decreases at low temperatures, and the electrode kinetics of electrode materials are sluggish, making discharge difficult at low temperatures. Furthermore, during discharge, the active material near the current collector consumes lithium ions, resulting in high electronic conductivity and low ionic conductivity, while the separator exhibits high ionic conductivity and low electronic conductivity. This imbalance in ionic and electronic conduction rates also reduces the battery's low-temperature performance.

[0003] The use of low-temperature electrolytes, low-temperature additives, and nano-sized or porous electrode materials have all improved the low-temperature performance of batteries. However, these methods cannot alleviate the imbalance of ionic and electronic conductivity within the electrodes (especially within thick electrodes). This causes lithium-ion batteries to face insufficient high-rate discharge at low temperatures, limiting the power performance of the battery pack. It is necessary to balance the ionic and electronic conductivity within the electrodes at low temperatures to maximize the capacity of the electrode active materials, thereby achieving the effects of high-rate discharge and extremely low-temperature discharge of the battery, and promoting its application in my country's high-altitude and cold regions. Summary of the Invention

[0004] To address the problem of insufficient discharge capacity within the electrodes of low-temperature lithium-ion batteries due to ion-electron imbalance near the current collector, the present invention provides a method for preparing a composite current collector for low-temperature, fast-discharging lithium-ion batteries. The composite current collector prepared by this method comprises an intermediate layer composed of a porous polymer and is plated on both sides with aluminum or copper layers, serving as the positive and negative electrodes, respectively. This porous current collector replaces traditional metal current collectors and can absorb and store a certain amount of electrolyte, thereby providing an ion source on one side of the current collector, achieving ion-electron balance and achieving high discharge capacity at low temperatures and high currents.

[0005] The purpose of the present invention is achieved through the following technical solutions:

[0006] A method for preparing a composite current collector for a low-lithium ion battery capable of rapid discharge at low temperature, comprising the following steps:

[0007] Step 1: Preparation of porous polymer substrate:

[0008] Step 1-1, Precursor No. 1 and Precursor No. 2 are blended in a mass ratio of 10-80:10-80, with a total mass of 0.5-5 g, added to 20-60 ml of reaction solvent No. 1, and stirred at a speed of 300-1500 r / min for 30-90 min;

[0009] Step 1-2: naturally evaporate the solvent, place it in a vacuum oven at 30-90°C for 5-24 hours to obtain a powdery substance;

[0010] Step 1-3: Add the powdered substance and precursor No. 3 at a mass ratio of 10-80:10-80, with a total mass of 1-10 g, to 20-60 ml of reaction solvent No. 2, and stir at a speed of 300-1500 r / min and 30-90° C. for 30-90 min to obtain a uniform polymer solution;

[0011] Steps 1-4: placing the polymer solution in an electrospinning device and ejecting it to form polymer-based fiber filaments with a diameter of 10 to 25 μm, which are then woven into a three-dimensional mesh-like porous polymer substrate as a substrate for preparing a composite current collector;

[0012] In this step, Precursor No. 1, Precursor No. 2, and Precursor No. 3 are selected from three of the group consisting of methyl polyethylene glycol methacrylate, methyl acrylate, 2-isocyanoethyl methacrylate, pentaerythritol tetraacrylate, pentaerythritol tetrakis(3-mercaptopropionic acid), acrylonitrile, polyethylene glycol diacrylate, and methyl methacrylate;

[0013] In this step, the mixture is stirred at a speed of 500 to 2000 r / min and irradiated with 100 to 2000 W ultraviolet light for 5 to 60 minutes;

[0014] In this step, reaction solvent No. 1 and reaction solvent No. 2 are selected from two of tetrahydrofuran, NMP, acetone, isopropanol, and ethanol;

[0015] Step 2: Preparation of metal-based prepreg:

[0016] Step 2-1, adding 5-20 mg of nano-sized metal particles to reaction solvent No. 3, and stirring at a speed of 300-1800 r / min for 0.5-6 h;

[0017] Step 2-2, add 0.2-0.8 mg of surfactant and continue stirring at a speed of 500-1500 r / min for 0.5-6 h;

[0018] Step 2-3, transferring the mixture obtained in step 2-2 to an ultrasonic machine and treating it at a power of 200 to 1600 W for 0.5 to 10 hours to obtain a metal-based prepreg;

[0019] In this step, the nano-scale metal particles are one of nano-silver particles, nano-palladium particles, nano-zinc particles, nano-gold particles, nano-iron particles, and nano-platinum particles with a diameter of 50 to 100 nm;

[0020] In this step, the reaction solvent No. 3 is one of water, isopropanol, ethanol, methanol, n-butanol, ethylene glycol, acetone, and toluene;

[0021] In this step, the surfactant is one of polyethylene glycol 600, polyethylene glycol 400, and sodium dodecylbenzene sulfonate;

[0022] Step 3: Preparation of porous composite metal current collector:

[0023] Step 3-1, immersing the porous polymer substrate in a metal-based pre-dip solution so that the surface of the porous polymer substrate is covered with conductive metal particles;

[0024] Step 3-2, prepare copper electroplating solution: add copper ion source, accelerator, inhibitor, and leveler to water at concentrations of 10-80 g / L, 1-5 mL / L, 0.5-8 mL / L, and 1-10 mL / L, respectively;

[0025] Step 3-3: Immerse the porous composite polymer substrate covered with conductive metal particles in a copper electroplating solution, connect a power supply, and maintain a constant temperature of 25°C at a current of 0.1 to 0.24 A / dm 2 Electroplating was performed at a current density of 20 to 100 s to obtain a porous composite copper current collector;

[0026] Step 3-4: placing the porous composite polymer substrate covered with conductive metal particles in a magnetron sputtering apparatus, adjusting the target material to an aluminum source, and performing sputtering at a voltage of 20 to 500 keV to obtain a porous composite aluminum current collector;

[0027] In this step, the accelerator is one of sodium dimethyldithiocarboxamide propane sulfonate (DPS), sodium 3-mercapto-1-propane sulfonate (MPS), and sodium polydisulfide propane sulfonate (SPS);

[0028] In this step, the inhibitor is one of polyether and polyol compounds;

[0029] In this step, the leveling agent is one of polyethyleneimine salts, EO-PO quaternary ammonium salts, polyethyleneimine quaternary ammonium salts, and polyamine substances.

[0030] Compared with the prior art, the present invention has the following advantages:

[0031] 1. The porous composite current collector prepared by the present invention has the function of soaking in electrolyte, so there is a sufficient ion source on the side close to the current collector. Compared with conventional current collectors, the porous composite current collector prepared by the present invention has lower internal resistance and high-rate discharge performance at low temperatures.

[0032] 2. The porous composite current collector prepared by the present invention is lighter than conventional metal current collectors, which is beneficial to the lightweighting of batteries and the realization of batteries with higher energy density.

[0033] 3. The porous composite current collector prepared by the present invention has the ability to store electrolyte, thus alleviating the attenuation caused by electrolyte drying up and extending the battery life. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 Schematic diagram of the preparation process of porous composite metal current collector;

[0035] Figure 2 This is a scanning electron microscope image of a porous composite metal current collector;

[0036] Figure 3 These are the high-rate discharge curves of conventional batteries and batteries using composite metal current collectors at low temperatures. DETAILED DESCRIPTION

[0037] The technical solution of the present invention is further described below with reference to the accompanying drawings, but is not limited thereto. Any modification or equivalent replacement of the technical solution of the present invention that does not depart from the spirit and scope of the technical solution of the present invention should be included in the scope of protection of the present invention.

[0038] Example 1:

[0039] This embodiment provides a method for preparing a porous current collector that can achieve low-temperature and high-power discharge of lithium-ion batteries. Figure 1 As shown, the method includes the following steps:

[0040] Step 1-1, methyl polyethylene glycol methacrylate and methyl acrylate were blended in a mass ratio of 10:30, with a total mass of 3 g, added to 40 ml of NMP, and stirred at a speed of 1000 r / min for 60 min while irradiating with 1500 W ultraviolet light for 20 min;

[0041] Step 1-2: naturally evaporate the solvent, place it in a vacuum oven at 80°C for 12 hours to obtain a powdery substance;

[0042] Step 1-3: Add the powdered substance and 2-isocyanatoethyl methacrylate at a mass ratio of 30:10, with a total mass of 4 g, to 30 ml of acetone, and stir at a speed of 1000 rpm and 70° C. for 60 min to obtain a uniform polymer solution;

[0043] Step 1-4: Place the polymer solution in an electrospinning device and spray it out to form polymer-based fiber filaments with a diameter of 10 μm, which are then woven into a three-dimensional mesh-like porous polymer substrate as a substrate for preparing a composite current collector.

[0044] Step 2: Preparation of metal-based prepreg:

[0045] Step 2-1, adding 8 mg of silver nanoparticles with a diameter of 50 nm to water and stirring at a speed of 1200 r / min for 2 h;

[0046] Step 2-2, add 0.3 mg of sodium dodecylbenzenesulfonate, and continue stirring at a speed of 1000 r / min for 3 h;

[0047] Step 2-3: Transfer the mixture obtained in step 2-2 to an ultrasonic machine and treat it at a power of 800 W for 2 hours to obtain a metal-based pre-dip solution.

[0048] Step 3: Preparation of porous composite metal current collector:

[0049] Step 3-1, immersing the porous polymer substrate in a metal-based pre-dip solution so that the surface of the porous polymer substrate is covered with conductive metal particles;

[0050] Step 3-2, prepare a copper electroplating solution: add a copper ion source, sodium dimethyldithiocarboxamide propane sulfonate (DPS), propylene oxide, and polyethyleneimine to water at concentrations of 50 g / L, 2 mL / L, 2.5 mL / L, and 3 mL / L, respectively;

[0051] Step 3-3: Immerse the porous composite polymer substrate covered with conductive metal particles in a copper electroplating solution, connect the power supply, and maintain a constant temperature of 25°C at a rate of 0.15A / dm 2 Electroplating was performed for 50 s at a current density of 100 nm to obtain a porous composite copper current collector;

[0052] Step 3-4: Place the porous composite polymer substrate covered with conductive metal particles in a magnetron sputtering apparatus, adjust the target material to an aluminum source, and sputter at a voltage of 200 keV to obtain a porous composite aluminum current collector, the morphology of which is as follows: Figure 2 shown.

[0053] The porous composite metal current collector prepared in the above steps can be used in the positive and negative current collectors of lithium-ion batteries or sodium-ion batteries. The specific application method is as follows:

[0054] (1) The positive electrode active material, electronic conductive material, binder and solvent of the battery are mixed in a mass ratio of 97:1.5:1.5:120. Similarly, the negative electrode active material, electronic conductive material, binder and solvent of the battery are mixed in a mass ratio of 92:3.5:4.5:120. The mixture is mixed in a planetary mixer for 30 minutes at a speed of 1000 r / min to obtain positive electrode slurry and negative electrode slurry, respectively. The battery active material is lithium nickel cobalt manganese oxide (NCM811), the negative electrode material is spherical graphite, the electronic conductive material is carbon nanotubes, and the binder is PVDF.

[0055] (2) The positive electrode slurry was coated on a porous aluminum current collector, and the negative electrode slurry was coated on a porous copper current collector. The cells were dried, rolled, assembled, and tested. As shown in Table 1, the battery using the porous current collector exhibited lower internal resistance at low temperatures compared to conventional current collectors.

[0056] Table 1

[0057]

[0058] Example 2:

[0059] This embodiment provides a method for preparing a porous current collector that can achieve low-temperature and high-power discharge of lithium-ion batteries. Figure 1 As shown, the method includes the following steps:

[0060] Step 1-1, methyl polyethylene glycol methacrylate and methyl acrylate were blended in a mass ratio of 10:30, with a total mass of 5 g, added to 40 ml of NMP, and stirred at a speed of 1000 r / min for 60 min while irradiating with 1500 W ultraviolet light for 20 min;

[0061] Step 1-2: naturally evaporate the solvent, place it in a vacuum oven at 80°C for 12 hours to obtain a powdery substance;

[0062] Step 1-3: Add the powdered substance and 2-isocyanatoethyl methacrylate at a mass ratio of 30:10, with a total mass of 4 g, to 30 ml of acetone, and stir at a speed of 1000 rpm and 70° C. for 60 min to obtain a uniform polymer solution;

[0063] Step 1-4: Place the polymer solution in an electrospinning device and spray it out to form polymer-based fiber filaments with a diameter of 10 μm, which are then woven into a three-dimensional mesh-like porous polymer substrate as a substrate for preparing a composite current collector.

[0064] Step 2: Preparation of metal-based prepreg:

[0065] Step 2-1, adding 5 mg of nano-zinc particles with a diameter of 80 nm to water and stirring at a speed of 1200 r / min for 2 h;

[0066] Step 2-2, add 0.3 mg of sodium dodecylbenzenesulfonate, and continue stirring at a speed of 1500 r / min for 2 h;

[0067] Step 2-3: Transfer the mixture obtained in step 2-2 to an ultrasonic machine and treat it at a power of 800 W for 2 hours to obtain a metal-based pre-dip solution.

[0068] Step 3: Preparation of porous composite metal current collector:

[0069] Step 3-1, immersing the porous polymer substrate in a metal-based pre-dip solution so that the surface of the porous polymer substrate is covered with conductive metal particles;

[0070] Step 3-2, prepare a copper electroplating solution: add a copper ion source, sodium dimethyldithiocarboxamide propane sulfonate (DPS), propylene oxide, and polyethyleneimine to water at concentrations of 50 g / L, 2 mL / L, 2.5 mL / L, and 3 mL / L, respectively;

[0071] Step 3-3: Immerse the porous composite polymer substrate covered with conductive metal particles in a copper electroplating solution, connect the power supply, and maintain a constant temperature of 25°C at a rate of 0.20A / dm 2 Electroplating was performed for 30s at a current density of 1000 nm to obtain a porous composite copper current collector;

[0072] Step 3-4: Place the porous composite polymer substrate covered with conductive metal particles in a magnetron sputtering apparatus, adjust the target material to an aluminum source, and sputter at a voltage of 200 keV to obtain a porous composite aluminum current collector, the morphology of which is as follows: Figure 2 shown.

[0073] The porous composite metal current collector prepared in the above steps can be used in the positive and negative current collectors of lithium-ion batteries or sodium-ion batteries. The specific application method is as follows:

[0074] (1) The positive electrode active material, the electronic conductive material, the binder and the solvent of the battery are mixed in a mass ratio of 96.5:2:1.5:120. Similarly, the negative electrode active material, the electronic conductive material, the binder and the solvent of the battery are mixed in a mass ratio of 92:3.5:4.5:120. The mixture is mixed in a planetary mixer for 30 minutes at a speed of 1000 r / min to obtain positive electrode slurry and negative electrode slurry, respectively. The battery active material is lithium cobalt oxide, the negative electrode material is flake graphite, the electronic conductive material is carbon nanotubes, and the binder is PVDF.

[0075] (2) Apply the positive electrode slurry to the porous aluminum current collector and the negative electrode slurry to the porous copper current collector, dry and roll, assemble the battery, and test. Figure 3 As shown in Figure 3, compared with conventional current collectors, the battery using porous current collectors has a higher capacity at 5 C discharge at low temperature.

[0076] Example 3:

[0077] This embodiment provides a method for preparing a porous current collector that can achieve low-temperature and high-power discharge of lithium-ion batteries. Figure 1 As shown, the method includes the following steps:

[0078] Step 1-1, pentaerythritol tetraacrylate and pentaerythritol tetrakis(3-mercaptopropionic acid) ester were blended in a mass ratio of 15:35 to a total mass of 4.5 g, added to 40 ml of NMP, and stirred at a speed of 1000 r / min for 60 min while irradiating with 1500 W ultraviolet light for 20 min;

[0079] Step 1-2: naturally evaporate the solvent, place it in a vacuum oven at 80°C for 12 hours to obtain a powdery substance;

[0080] Step 1-3: Add the powdered substance and methyl polyethylene glycol methacrylate in a mass ratio of 30:12, with a total mass of 4 g, to 30 ml of acetone, and stir at a speed of 1000 rpm and 70° C. for 60 min to obtain a uniform polymer solution;

[0081] Step 1-4: Place the polymer solution in an electrospinning device and spray it out to form polymer-based fiber filaments with a diameter of 15 μm, which are then woven into a three-dimensional mesh-like porous polymer substrate as a substrate for preparing a composite current collector.

[0082] Step 2: Preparation of metal-based prepreg:

[0083] Step 2-1, adding 5 mg of nano-zinc particles with a diameter of 80 nm to water and stirring at a speed of 1200 r / min for 2 h;

[0084] Step 2-2, add 0.3 mg of sodium dodecylbenzenesulfonate, and continue stirring at a speed of 1500 r / min for 2 h;

[0085] Step 2-3: Transfer the mixture obtained in step 2-2 to an ultrasonic machine and treat it at a power of 800 W for 2 hours to obtain a metal-based pre-dip solution.

[0086] Step 3: Preparation of porous composite metal current collector:

[0087] Step 3-1, immersing the porous polymer substrate in a metal-based pre-dip solution so that the surface of the porous polymer substrate is covered with conductive metal particles;

[0088] Step 3-2, prepare a copper electroplating solution: add a copper ion source, sodium dimethyldithiocarboxamide propane sulfonate (DPS), propylene oxide, and polyethyleneimine to water at concentrations of 50 g / L, 2 mL / L, 2.5 mL / L, and 3 mL / L, respectively;

[0089] Step 3-3: Immerse the porous composite polymer substrate covered with conductive metal particles in a copper electroplating solution, connect the power supply, and maintain a constant temperature of 25°C at a rate of 0.20A / dm 2 Electroplating was performed for 30s at a current density of 1000 nm to obtain a porous composite copper current collector;

[0090] Step 3-4: Place the porous composite polymer substrate covered with conductive metal particles in a magnetron sputtering apparatus, adjust the target material to an aluminum source, and sputter at a voltage of 200 keV to obtain a porous composite aluminum current collector, the morphology of which is as follows: Figure 2 shown.

[0091] The porous composite metal current collector prepared in the above steps can be used in the positive and negative current collectors of lithium-ion batteries or sodium-ion batteries. The specific application method is as follows:

[0092] (1) The positive electrode active material, the electronic conductive material, the binder and the solvent of the battery are mixed in a mass ratio of 96.5:2:1.5:120. Similarly, the negative electrode active material, the electronic conductive material, the binder and the solvent of the battery are mixed in a mass ratio of 92:3.5:4.5:120. The mixture is mixed in a planetary mixer for 30 minutes at a speed of 1000 r / min to obtain positive electrode slurry and negative electrode slurry, respectively. The battery active material is lithium cobalt oxide, the negative electrode material is flake graphite, the electronic conductive material is carbon nanotubes, and the binder is PVDF.

[0093] (2) The positive electrode slurry of the battery is coated on the porous aluminum current collector, and the negative electrode slurry is coated on the surface of the porous copper current collector, and then dried and rolled to assemble the battery.

[0094] Example 4:

[0095] The difference between this embodiment and embodiment 1 is that the reaction solvent No. 1 and reaction solvent No. 2 are replaced with isopropyl alcohol and ethanol, respectively, and the same effect can be achieved.

Claims

1. A method for preparing a composite current collector for a low-lithium ion battery capable of rapid discharge at low temperature, characterized in that The method comprises the following steps: Step 1: Preparation of porous polymer substrate: Step 1-1: Precursor No. 1 and Precursor No. 2 are blended at a mass ratio of 10-80:10-80, with a total mass of 0.5-5 g, added to 20-60 ml of reaction solvent No. 1, and stirred at a speed of 300-1500 r / min for 30-90 min; Step 1-2: naturally evaporate the solvent, place it in a vacuum oven at 30-90°C for 5-24 hours to obtain a powdery substance; Step 1-3: Add the powdered substance and precursor No. 3 at a mass ratio of 10-80:10-80, with a total mass of 1-10 g, to 20-60 ml of reaction solvent No. 2, and stir at a speed of 300-1500 r / min and 30-90°C for 30-90 min to obtain a uniform polymer solution; Steps 1-4: placing the polymer solution in an electrospinning device and spraying it out to form polymer-based fiber filaments, which are then woven into a three-dimensional porous polymer substrate; The precursor No. 1, precursor No. 2 and precursor No. 3 are selected from three of the group consisting of methyl polyethylene glycol methacrylate, methyl acrylate, 2-isocyanoethyl methacrylate, pentaerythritol tetraacrylate, pentaerythritol tetrakis(3-mercaptopropionic acid), acrylonitrile, polyethylene glycol diacrylate and methyl methacrylate; Step 2: Preparation of metal-based prepreg: Step 2-1, add 5-20 mg of nano-sized metal particles to reaction solvent No. 3 and stir at a speed of 300-1800 r / min for 0.5-6 h; Step 2-2: Add 0.3-0.8 mg of surfactant and continue stirring at 500-1500 r / min for 0.5-6 h; Step 2-3, transferring the mixture obtained in step 2-2 to an ultrasonic machine and treating it at a power of 200-1600 W for 0.5-10 hours to obtain a metal-based prepreg; Step 3: Preparation of porous composite metal current collector: Step 3-1, immersing the porous polymer substrate in a metal-based pre-dip solution so that the surface of the porous polymer substrate is covered with conductive metal particles; Step 3-2, prepare copper electroplating solution: add copper ion source, accelerator, inhibitor, and leveler to water at concentrations of 10-80 g / L, 1-5 mL / L, 0.5-8 mL / L, and 1-10 mL / L, respectively; Step 3-3: Immerse the porous composite polymer substrate covered with conductive metal particles in a copper electroplating solution, connect a power supply, and conduct electricity at a constant temperature of 25°C at a rate of 0.1-0.24 A / dm 2 The porous composite copper current collector was obtained by electroplating at a current density of 20~100 s.

2. The method for preparing a composite current collector for a low-lithium ion battery capable of rapid discharge at low temperature according to claim 1, characterized in that In the step 1, the mixture is stirred at a speed of 500 to 2000 r / min and irradiated with 100 to 2000 W ultraviolet light for 5 to 60 min.

3. The method for preparing a composite current collector for a low-lithium ion battery capable of rapid discharge at low temperature according to claim 1, characterized in that In step 1, reaction solvent No. 1 and reaction solvent No. 2 are selected from two of tetrahydrofuran, NMP, acetone, isopropyl alcohol, and ethanol; and the nano-scale metal particles are one of nano-silver particles, nano-palladium particles, nano-zinc particles, nano-gold particles, nano-iron particles, and nano-platinum particles.

4. The method for preparing a composite current collector for a low-lithium ion battery capable of rapid discharge at low temperature according to claim 1 or 3, characterized in that The diameter of the nano-scale metal particles is 50-100 nm.

5. The method for preparing a composite current collector for a low-lithium ion battery capable of rapid discharge at low temperature according to claim 1, characterized in that In step 1, the diameter of the polymer-based fiber filament is 10-25 μm.

6. The method for preparing a composite current collector for a low-lithium ion battery capable of rapid discharge at low temperature according to claim 1, characterized in that In step 2, the reaction solvent No. 3 is one of water, isopropanol, ethanol, methanol, n-butanol, ethylene glycol, acetone, and toluene; and the surfactant is one of polyethylene glycol 600, polyethylene glycol 400, and sodium dodecylbenzenesulfonate.

7. The method for preparing a composite current collector for a low-lithium ion battery capable of rapid discharge at low temperature according to claim 1, characterized in that In step 3, the accelerator is one of sodium dimethyldithiocarboxamide propane sulfonate, sodium 3-mercapto-1-propane sulfonate, and sodium polydisulfide propane sulfonate; the inhibitor is one of propylene oxide, polyether, and polyol compounds; and the leveler is one of polyethyleneimine salts, EO-PO quaternary ammonium salts, and polyethyleneimine quaternary ammonium salts.

8. The method for preparing a composite current collector for a low-lithium ion battery capable of rapid discharge at low temperature according to claim 1, characterized in that The step 3-3 is replaced by: placing the porous composite polymer substrate covered with conductive metal particles in a magnetron sputtering apparatus, adjusting the target material to an aluminum source, and sputtering at a voltage of 20-500 keV to obtain a porous composite aluminum current collector.

9. Use of a composite current collector prepared by the method according to any one of claims 1 to 8 in a lithium ion battery or a sodium ion battery.

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