A soluble aluminum-based composite material and a method of making and using the same

Abstract

The application discloses a kind of soluble aluminum-based composite material, it is the sheet material with the thickness of 12-35 μm, it is composed of 50-70wt% aluminum powder, 25-40wt% water-soluble binder and 5-10wt% conductive agent;The water-soluble binder is PVA, the particle size of the aluminum powder 0.1-3 μm, the particle size of the conductive agent powder 0.1-1.2 μm, it is one or more in carbon black, carbon nanotube, graphite, SuperP, SuperS, koten black, acetylene black;Its preparation method and application are also disclosed;The aluminum-based composite material of the application can be used as the current collector material of the replacement aluminum foil, the aluminum-based composite material is easy to dissolve in water, can realize the complete dissolution of aluminum foil in water environment, realize the complete self-destruction of electrical device, the aluminum-based composite material of the application can be well and electrode material bonding, contact area is larger, can effectively improve the effective capacity of lithium battery.

Description

Technical Field

[0001] This invention patent belongs to the field of electrochemical energy storage, specifically relating to a soluble aluminum-based composite material, its preparation method, and a current collector for the positive electrode of a lithium battery. Background Technology

[0002] With increasing awareness of environmental protection, recyclable and renewable energy has become a key industry for development in countries around the world. In recent years, the market share of new energy lithium battery vehicles has been rising year by year, and the demand for lithium battery energy storage from wind power and solar power plants is growing stronger. As a key material for new energy lithium batteries, the market demand for aluminum foil current collectors for lithium batteries is expanding accordingly.

[0003] Currently, aluminum foil is the primary material for positive electrode current collectors. However, existing aluminum foil methods for this purpose have several drawbacks. For example, there are issues with the contact area and adhesion between the aluminum foil and the electrode material. The limited contact area and weak adhesion lead to increased interfacial contact resistance, which in turn increases the internal resistance of the lithium-ion battery. This not only affects the rate performance of the lithium-ion battery but may also hinder its cycle stability. Furthermore, the rigidity of aluminum foil limits the contact area with the positive electrode material within the electrode sheet, further impacting the internal resistance of the positive electrode.

[0004] Furthermore, in certain specialized fields, such as the use of lithium batteries embedded in the human body, aluminum foil is not suitable as a metal current collector because it is not easily eliminated from the body. For instance, some specialized equipment uses lithium batteries for power, but to protect the confidentiality of this equipment, a self-destruct mechanism is required for the lithium batteries. Aluminum foil is typically difficult to self-destruct, thus the analysis of the lithium batteries could lead to the deduction of information about the specialized equipment, posing a risk of leaks. Summary of the Invention

[0005] Based on the aforementioned main problems, namely the limitations of existing aluminum foil in terms of contact area and adhesion to electrode materials, and the difficulty in self-destruction of existing aluminum foil leading to potential leakage, one objective of this invention is to provide a soluble aluminum-based composite material that can serve as a current collector material to replace aluminum foil. This material is easily soluble in water, allowing for complete dissolution of aluminum foil in an aqueous environment, thus enabling complete self-destruction of the electrical device. Furthermore, the aluminum-based composite material of this invention can bond well with electrode materials, resulting in a large contact area and effectively improving the effective capacity of lithium batteries.

[0006] The technical solution adopted by the present invention to solve its technical problem is: a soluble aluminum-based composite material, which is a sheet material with a thickness of 12-35 μm, and the content of each component by weight percentage is 50-70 wt% aluminum powder, 25-40 wt% water-soluble binder and 5-10 wt% conductive agent; the water-soluble binder is PVA (polyvinyl alcohol), the aluminum powder has a particle size of 0.1-3 μm, and the conductive agent powder has a particle size of 0.1-1.2 μm, and is one or more of carbon black, carbon nanotubes, graphite, SuperP, SuperS, Ketjen black and acetylene black.

[0007] Furthermore, the contents of each component, calculated by weight percentage, are as follows: aluminum powder content is 63.5 wt%, water-soluble binder content is 27.5 wt%, and conductive agent content is 9 wt%. This specific combination of aluminum powder and conductive agent content can effectively improve the electrical conductivity of the aluminum-based composite material and effectively reduce its internal resistance.

[0008] A second objective of this invention is to provide a method for preparing a soluble aluminum-based composite material, comprising the following steps:

[0009] (1) Weigh 27.5 wt% of water-soluble binder polyvinyl alcohol and dissolve it in 30 wt% methanol or ethanol to form a water-soluble binder organic solution;

[0010] (2) Weigh 63.5 wt% of aluminum powder with a particle size of 0.5 to 10 μm in a nitrogen atmosphere, add it in three batches to the organic solution obtained in step 1), and continuously sonicate and stir to ensure that the aluminum powder and polyvinyl alcohol are fully and evenly mixed. Then add 9 wt% of conductive agent with a particle size of 0.1 to 0.6 μm, continue stirring and sonicating to obtain a uniform mixture, and evaporate the organic solvent to obtain the pretreated mixture.

[0011] (3) The pretreated mixture is placed in a hot press at a temperature of 35-60°C and a pressure of 500-1000 kg for 1-2 hours, and then cooled naturally to obtain a soluble aluminum-based composite material for lithium batteries.

[0012] The third objective of this invention is to provide a current collector for the above-mentioned soluble aluminum-based composite material as a positive electrode of a lithium battery.

[0013] The fourth objective of this invention is to provide a lithium battery that uses the above-mentioned current collector.

[0014] The beneficial technical effects obtained by this invention are as follows:

[0015] The soluble aluminum-based composite material provided by this invention is soluble in water and can be used as a component of lithium batteries in marine special equipment. In the event of potential leakage of special equipment information, the lithium battery can achieve complete self-destruction by dissolving in water.

[0016] The aluminum-based composite material provided by this invention can make good contact with the positive electrode material. This is mainly because the aluminum-based composite material of this invention is also made of aluminum powder and conductive agent powder bonded together by a water-soluble binder. The positive electrode material is also made of positive electrode active material powder, conductive agent and other powder additives bonded together by a water-soluble binder. The powders can make good contact with each other during the hot pressing of the lithium battery slurry, thereby increasing the effective contact area and improving the overall performance of the lithium battery.

[0017] This invention utilizes the effective particle size combination of aluminum powder and conductive agent powder to achieve electrical conductivity comparable to that of aluminum foil current collectors, while also possessing good water solubility. Detailed Implementation

[0018] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. It should be understood that the following description is merely illustrative and is not intended to limit the invention.

[0019] Unless otherwise specified, the raw materials and equipment used in this invention can be purchased from the market or are commonly used in the field. Unless otherwise specified, the methods in the embodiments are conventional methods in the field.

[0020] The following description, in conjunction with specific implementation methods, provides further details. Example 1

[0021] This embodiment discloses a soluble aluminum-based composite material, prepared by the following steps: 40 wt% of polyvinyl alcohol water-soluble binder powder is weighed and dissolved in 30 wt% ethanol solvent; 51 wt% of aluminum powder with a particle size of 3 μm is weighed and added in three batches to the ethanol solution containing polyvinyl alcohol; the mixture is continuously sonicated and stirred to ensure that the aluminum powder and polyvinyl alcohol are fully and uniformly mixed; then 9 wt% of carbon black with a particle size of 0.6 μm is added, and stirring and sonication are continued to obtain a uniform mixture; the organic solvent is evaporated to obtain a pretreated mixture; the pretreated mixture is placed in a hot press at a temperature of 53°C and a pressure of 800 kg for 1.5 h, and then naturally cooled to obtain a soluble aluminum-based composite material for lithium batteries.

[0022] The particle size distribution of the aluminum powder and conductive agent can effectively improve the conductivity of aluminum-based composite materials, increase the contact area with electrode materials, reduce interfacial resistance, and improve the overall performance of lithium batteries.

[0023] Resistivity Testing: The aluminum-based composite material from Example 1 was subjected to a four-wire method for resistivity testing of aluminum foil to evaluate the conductivity of the current collector, specifically referring to GB / T22638.6—2008 "Aluminum Foil Test Methods Part 6: Determination of DC Resistance". Connect the aluminum-based composite material sample to the four-wire resistance meter using wires. Ensure a secure connection and good contact. The four-wire method requires two pairs of wires: one pair for transmitting current (current wire) and the other pair for measuring voltage (voltage wire). Set appropriate test parameters, such as current magnitude and test time, based on the dimensions (length, cross-sectional area) of the aluminum-based composite material sample and the expected resistivity range. Turn on the power and start the four-wire resistance meter. Begin the test according to the instrument's operating instructions. The instrument will automatically transmit current to the aluminum-based composite material sample and measure the voltage. After the test, the instrument will display the resistance value of the aluminum-based composite material sample. Record this value for subsequent calculations. Calculate the resistivity ρ: ρ = R * S / L, where R is the measured resistance value, S is the cross-sectional area of ​​the aluminum-based composite material sample, and L is the length of the aluminum-based composite material sample.

[0024] Water solubility test of aluminum-based composite materials: The prepared aluminum-based composite material was used as the test sample. The prepared aluminum-based composite material was placed in a certain volume of aqueous solution. The aqueous solution was kept magnetically stirred. After 10 minutes, it was observed whether the aluminum-based composite material was completely dissolved, partially dissolved, or not dissolved. Complete dissolution means that there are no blocky or sheet-like materials and the dissolved materials in the aqueous solution are uniformly dispersed. Partial dissolution means that there are fragmented or blocky materials in the solution. Not dissolved means that the positive electrode slurry on the aluminum-based composite material sheet is not dissolved. For easy recording, complete dissolution is marked as 3, partial dissolution is marked as 2, and not dissolved is marked as 1. The data of specific examples are shown in the table below. Example 2

[0025] This embodiment discloses a soluble aluminum-based composite material, prepared by the following steps: 25 wt% of polyvinyl alcohol water-soluble binder powder is weighed and dissolved in 30 parts by weight of ethanol solvent; 63.5 wt% of aluminum powder with a particle size of 0.5 μm is weighed and added in three batches to the ethanol solution containing polyvinyl alcohol; the mixture is continuously sonicated and stirred to ensure that the aluminum powder and polyvinyl alcohol are fully and uniformly mixed; then 9 wt% of carbon nanotubes with a particle size of 0.6 μm are added, and stirring and sonication are continued to obtain a uniform mixture; the organic solvent is evaporated to obtain a pretreated mixture; the pretreated mixture is placed in a hot press at a temperature of 53°C and a pressure of 800 kg for 1.5 h, and then naturally cooled to obtain a soluble aluminum-based composite material for lithium batteries. Example 3

[0026] This embodiment discloses a soluble aluminum-based composite material, prepared by the following steps: 40 wt% of polyvinyl alcohol water-soluble binder powder is weighed and dissolved in 30 wt% ethanol solvent; 50 wt% of aluminum powder with a particle size of 10 μm is weighed and added in three batches to the ethanol solution containing polyvinyl alcohol; the mixture is continuously sonicated and stirred to ensure that the aluminum powder and polyvinyl alcohol are fully and uniformly mixed; then 10 wt% of graphite with a particle size of 0.6 μm is added, and stirring and sonication are continued to obtain a uniform mixture; the organic solvent is evaporated to obtain a pretreated mixture; the pretreated mixture is placed in a hot press at a temperature of 53°C and a pressure of 800 kg for 1.5 h, and then naturally cooled to obtain a soluble aluminum-based composite material for lithium batteries. Example 4

[0027] This embodiment discloses a soluble aluminum-based composite material, prepared by the following steps: 26.5 wt% of polyvinyl alcohol water-soluble binder powder is weighed and dissolved in 30 wt% ethanol solvent; 68.5 wt% of aluminum powder with a particle size of 3 μm is weighed and added in three batches to the ethanol solution containing polyvinyl alcohol; the mixture is continuously sonicated and stirred to ensure that the aluminum powder and polyvinyl alcohol are fully and uniformly mixed; then 5 wt% of SuperP and / or SuperS with a particle size of 0.1 μm is added, and stirring and sonication are continued to obtain a uniform mixture; the organic solvent is evaporated to obtain a pretreated mixture; the pretreated mixture is placed in a hot press at a temperature of 53°C and a pressure of 800 kg for 1.5 h, and then naturally cooled to obtain a soluble aluminum-based composite material for lithium batteries. Example 5

[0028] This embodiment discloses a soluble aluminum-based composite material, prepared by the following steps: 27.5 wt% of polyvinyl alcohol water-soluble binder powder is weighed and dissolved in 30 wt% ethanol solvent; 70 wt% of aluminum powder with a particle size of 3 μm is weighed and added in three batches to the ethanol solution containing polyvinyl alcohol; the mixture is continuously sonicated and stirred to ensure that the aluminum powder and polyvinyl alcohol are fully and uniformly mixed; then 5 wt% of Ketjen Black and / or acetylene black with a particle size of 0.1 μm is added, and stirring and sonication are continued to obtain a uniform mixture; the organic solvent is evaporated to obtain a pretreated mixture; the pretreated mixture is placed in a hot press at a temperature of 53°C and a pressure of 800 kg for 1.5 h, and then naturally cooled to obtain a soluble aluminum-based composite material for lithium batteries.

[0029] Comparative Example 1: Weigh 30 parts by weight of polyvinyl alcohol powder and dissolve it in 30 parts by weight of ethanol solvent. Weigh 48 parts by weight of aluminum powder with a particle size of 3 μm and add it in three batches to the ethanol solution containing polyvinyl alcohol. Continuously sonicate and stir to ensure that the aluminum powder and polyvinyl alcohol are fully and uniformly mixed. Then add 22 parts by weight of carbon black with a particle size of 0.1 μm, continue stirring and sonicating to obtain a uniform mixture. Evaporate the organic solvent to obtain a pretreated mixture. Place the pretreated mixture in a hot press at a temperature of 53℃ and a pressure of 800 kg for 1.5 h, and then allow it to cool naturally to obtain a soluble aluminum-based composite material for lithium batteries.

[0030] Comparative Example 2: Weigh 30 parts by weight of polyvinyl alcohol powder and dissolve it in 30 parts by weight of ethanol solvent. Weigh 48 parts by weight of aluminum powder with a particle size of 3 μm and add it in three batches to the ethanol solution containing polyvinyl alcohol. Continuously sonicate and stir to ensure that the aluminum powder and polyvinyl alcohol are fully and uniformly mixed. Then add 22 parts by weight of carbon black with a particle size of 0.1 μm, continue stirring and sonicating to obtain a uniform mixture. Evaporate the organic solvent to obtain a pretreated mixture. Place the pretreated mixture in a hot press at a temperature of 53℃ and a pressure of 800 kg for 1.5 h, and then allow it to cool naturally to obtain a soluble aluminum-based composite material for lithium batteries.

[0031] Comparative Example 3: Pure aluminum foil of the same size as in Example 1 was used for testing.

[0032] The physical performance parameters of each embodiment and comparative example are shown in the table below.

[0033] .

[0034] As can be seen from the data in the table above, Examples 1 to 3 compared the effects of aluminum powder with different particle sizes on conductivity. The aluminum powder with different particle sizes has a significant impact on the conductivity of aluminum-based composite materials.

[0035] A comparison of the data from Examples 1 to 5 reveals that conductive agents of different particle sizes also have a significant impact on the conductivity of aluminum-based composite materials.

[0036] Comparing the data from Comparative Examples 1-2 with the data from Examples 1-5, it was found that different component ratios have a significant impact on conductivity.

[0037] Compared with Comparative Example 3, Examples 1-5 show that the conductivity of aluminum-based composite materials is slightly worse than that of aluminum foil, but it can still achieve comparable conductivity and is soluble, which further expands the selection and development of current collectors and their application scenarios.

[0038] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A soluble aluminum-based composite material, characterized in that: It is a sheet-like material with a thickness of 12–35 μm, composed of 50–70 wt% aluminum powder, 25–40 wt% water-soluble binder, and 5–10 wt% conductive agent; the water-soluble binder is polyvinyl alcohol, the aluminum powder has a particle size of 0.1–3 μm, and the conductive agent powder has a particle size of 0.1–1.2 μm, and is one or more of carbon black, carbon nanotubes, graphite, SuperP, SuperS, Ketjen black, and acetylene black; the preparation steps are as follows: (1) Weigh out polyvinyl alcohol powder and dissolve it in 1 to 1.5 times the amount of methanol or ethanol to form a polyvinyl alcohol organic solution; (2) Weigh aluminum powder in a nitrogen atmosphere, add it in batches to an organic solution and stir ultrasonically to make the aluminum powder and water-soluble binder fully and evenly mixed. Then add a conductive agent and continue stirring and ultrasonicating to obtain a uniform mixture. Volatilize the mixture to obtain the pretreated mixture. (3) The pretreated mixture is placed in a hot press at a temperature of 35-60°C and a pressure of 500-1000 kg for 1-2 hours, and then cooled naturally to obtain a soluble aluminum-based composite material.

2. The soluble aluminum-based composite material according to claim 1, characterized in that, The aluminum powder content is 63.5 wt%, the water-soluble binder content is 27.5 wt%, and the conductive agent content is 9 wt%.

3. A current collector for the positive electrode of a lithium battery using a soluble aluminum-based composite material as described in claim 1.

4. A lithium battery, characterized in that, The current collector as described in claim 3 is used.