Aluminum battery

Abstract

To provide an aluminum battery that extends its lifespan and maintains superior conductivity.SOLUTION: An aluminum battery of the present invention comprises a positive electrode, a negative electrode, a separator, and an electrolyte. The positive electrode comprises a metal substrate and a coating layer. The coating layer is formed on a metal substrate, and the coating layer material comprises conductive carbon material and water-soluble conductive polymer, with a layer count of five or fewer layers. The separator is positioned between the positive electrode and the negative electrode. The electrolyte is impregnated into the separator, the positive electrode, and the negative electrode.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to aluminum batteries. [Background technology]

[0002] Based on the mechanism by which the positive electrode of an aluminum battery accommodates and permeates the active material and the requirements for conductive performance, highly conductive materials with a layered structure (such as graphite) are generally selected. However, during the continuous charge and discharge process, the layered structure is prone to expansion and collapse due to structural defects, leading to a shortened service life. Summary of the Invention [Problem to be solved by the invention]

[0003] During the continuous charge-discharge process, the layered structure of the aluminum battery cathode is prone to swelling and collapse due to its structural defects, leading to a shortened service life. [Means for solving the problem]

[0004] The present invention provides an aluminum battery that can extend its life and maintain better conductivity.

[0005] The aluminum battery of the present invention includes a positive electrode, a negative electrode, a separator, and an electrolyte. The positive electrode includes a metal substrate and a coating layer. The coating layer is disposed on the metal substrate, and the coating layer material includes a conductive carbon material and a water-soluble conductive polymer in five or less layers. The separator is disposed between the positive electrode and the negative electrode. The electrolyte is impregnated into the separator, the positive electrode, and the negative electrode.

[0006] In one embodiment of the present invention, the weight ratio of the conductive carbon material to the water-soluble conductive polymer is between 10:1 and 10:5.

[0007] In one embodiment of the present invention, the conductive carbon material comprises graphene and the water-soluble conductive polymer comprises a polymer blend of poly(3,4-dioxyethylthiophene) and polystyrene sulfonic acid.

[0008] In one embodiment of the present invention, the molar ratio of the poly(3,4-dioxyethylthiophene) to the polystyrene sulfonic acid is between 1:1.6 and 1:5.

[0009] In one embodiment of the present invention, the weight ratio of the conductive carbon material in the coating layer is between 65 wt% and 80 wt%.

[0010] In one embodiment of the present invention, the weight ratio of the water-soluble conductive polymer in the coating layer is between 8 wt% and 13 wt%.

[0011] In one embodiment of the present invention, the coating layer further comprises an auxiliary agent, which comprises a neutralizing agent, an antifoaming agent, a thickener, a solvent and an adhesive, or a combination thereof.

[0012] In one embodiment of the present invention, the weight ratio of the auxiliary agent in the coating layer is between 7 wt% and 27 wt%.

[0013] In one embodiment of the invention, the adhesive is a non-conductive polymer.

[0014] In one embodiment of the present invention, the material of the metal substrate comprises titanium, nickel, or a combination thereof. [Effects of the Invention]

[0015] In light of the above, the coating layer material for the positive electrode of the present invention comprises a conductive carbon material with at least 5 layers or less and a water-soluble conductive polymer, and the combination of the two increases the structural stability of the positive electrode, and these materials have conductive ability, thereby improving the lifespan of aluminum batteries and maintaining better conductivity.

[0016] In order to make the above features and advantages of the present invention more clearly comprehensible, the following embodiments are shown and described in detail in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a schematic diagram showing the results of a life test for an example and a comparative example. [Figure 2] FIG. 2 is a schematic diagram showing the results of resistance tests of Examples and Comparative Examples. DETAILED DESCRIPTION OF THE INVENTION

[0018] In order to make the contents of the present invention easier to understand, the following embodiments are specifically given as examples in which the present invention can be implemented. For the sake of clarity, many practical details are described in the following description. However, it should be understood that these practical details should not be used to limit the present invention. That is, in some embodiments of the present invention, these practical details are not necessary.

[0019] In order to clearly explain the present invention, the description of known aluminum battery design rules is omitted here, but a person having ordinary skill in the relevant technical field can design according to actual needs without departing from the spirit and scope of the present invention.

[0020] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0021] Unless otherwise stated, the term "between" as used herein to define a numerical range is intended to cover a range equal to and between the stated end values; for example, a size range between a first value and a second value means that the size range can cover the first value, the second value, and any value between the first value and the second value.

[0022] In this embodiment, the aluminum battery includes a positive electrode, a negative electrode, a separator, and an electrolyte, the separator is disposed between the positive electrode and the negative electrode, the electrolyte is impregnated into the separator, the positive electrode, and the negative electrode, and the positive electrode includes a metal substrate and a coating layer disposed thereon. Here, the positive electrode, the negative electrode, the separator, and the electrolyte can be arranged relative to each other by any suitable method known in the field of aluminum batteries, and the present invention is not limited thereto.

[0023] Furthermore, the coating layer material includes at least five layers of a conductive carbon material and a water-soluble conductive polymer. The combination of the two improves the structural stability of the positive electrode, and these materials have conductive properties, thereby improving the lifespan of aluminum batteries and maintaining better conductivity. More specifically, if the conductive carbon material has too many layers (e.g., graphite with 10 or more layers), the polymer material cannot penetrate between the layers without introducing additional energy. Therefore, in the present invention, a layer number (e.g., 3 to 5 layers) is selected to allow the polymer material to penetrate more easily, thereby achieving a better interpenetration effect and effectively repairing structural defects in the conductive carbon material. Here, the layered structure can be stretched in a first direction, and the polymer material can be stretched in a second direction perpendicular to the first direction, thereby forming a stable structure in which the two intersect vertically and horizontally, but the present invention is not limited thereto.

[0024] On the other hand, in the manufacturing process, the water-soluble conductive polymer can be used as a dispersion system in water, i.e., the water-soluble polymer can be dissolved in water without precipitation, which has an environmentally friendly effect. For example, after drying the coating layer of the positive electrode of the present invention, the positive electrode does not contain organic solvents and can be considered an environmentally friendly electrode, but the present invention is not limited thereto. Here, in the manufacturing process, by setting the solid content of the slurry to 30 wt% or less (the total weight of the solids in the slurry divided by the total weight of the slurry), the slurry has fluidity and can be reliably applied to the metal substrate. In one embodiment, the solid content of the slurry is, for example, 16 wt%, which provides favorable operability, but the present invention is not limited thereto.

[0025] In some embodiments, the weight ratio of the conductive carbon material to the water-soluble conductive polymer is between 10:1 and 10:5 (e.g., 10:1), and / or the molar ratio of poly(3,4-dioxyethylthiophene) to polystyrene sulfonic acid is between 1:1.6 and 1:5, which allows the water-soluble conductive polymer to more reliably penetrate between the layers of the conductive carbon material and further improves structural stability, but the present invention is not limited thereto. Here, an appropriate molar ratio of the water-soluble conductive polymer can be selected depending on the interlayer spacing of the conductive carbon material.

[0026] In some embodiments, the conductive carbon material includes graphene, which has a higher specific surface area, conductivity, and structural strength, thereby avoiding the problem of reduced performance in aluminum batteries caused by excessive resistance. To improve structural defects such as stacking failures and irregularities that occur in graphene release sheet materials, a water-soluble conductive polymer including a polymer blend of poly(3,4-dioxyethylthiophene) and polystyrene sulfonic acid (PEDOT:PSS) is introduced to repair these defects, thereby achieving a synergistic effect between the two and achieving better life performance. However, the present invention is not limited to this. For example, the polymer blend of poly(3,4-dioxyethylthiophene) and polystyrene sulfonic acid is a product of Tairitsu Polymer Co., Ltd., called WED-SM.

[0027] In some embodiments, the weight ratio of the conductive carbon material in the coating layer is between 65 wt% and 80 wt%, and the weight ratio of the water-soluble conductive polymer in the coating layer is between 8 wt% and 13 wt%, although the present invention is not limited thereto.

[0028] In some embodiments, the coating layer further comprises an auxiliary agent, the auxiliary agent comprising a neutralizing agent, an antifoaming agent, a thickener, a solvent, an adhesive, or a combination thereof, and the weight ratio of the auxiliary agent in the coating layer is between 7 wt% and 27 wt%, but the present invention is not limited thereto.

[0029] In some embodiments, the adhesive is a non-conductive polymer, such as sodium carboxymethylcellulose (CMC) / styrene butadiene rubber (SBR), the neutralizing agent is triethanolamine or AMP-95, whose main active ingredient is aminomethyl propanol, the solvent is water, ethylene glycol (EG), or a combination thereof, and the thickener is an aqueous thickener, such as VIS4, whose main active ingredient is an oil dispersion of a renewable polymer.

[0030] In some embodiments, the metal substrate material includes titanium, nickel, or a combination thereof, although the invention is not limited thereto.

[0031] In some embodiments, the thickness of the metal substrate is between 30 micrometers (μm) and 100 μm, and the thickness of the coating layer is between 50 μm and 70 μm, although the invention is not limited thereto.

[0032] In some embodiments, the electrolyte includes an aluminum halide, an ionic liquid, or a combination thereof, where the aluminum halide includes aluminum chloride (AlCl) and the ionic liquid includes, but is not limited to, 1-ethyl-3-methylimidazolium chloride.

[0033] In some embodiments, the negative electrode material comprises aluminum foil, the separator material comprises glass fiber or the like, the negative electrode thickness is between 30 μm and 100 μm, and the separator thickness is between 30 μm and 350 μm, although the invention is not limited thereto.

[0034] The effects achieved by the aluminum battery of the present invention will be described in more detail below with reference to examples and comparative examples. Although the following embodiments are described, the details of the materials used and the processes can be changed as appropriate without departing from the scope of the present invention, and the present invention should not be construed as being limited by the following embodiments.

[0035] <Comparative Example 1>

[0036] Aluminum foil was cut to obtain a negative electrode (0.05 mm thick, 14 mm diameter). A coating layer (made of graphite, conductive carbon black, and adhesive (carboxymethyl cellulose (CMC) / styrene-butadiene rubber (SBR)) in a 1:4 ratio, with a weight ratio of 90:2:8) was formed on nickel foil (0.03 mm thick, 15 mm diameter) to obtain a positive electrode. Next, the negative electrode, separator, and positive electrode were arranged in this order in a battery containing a large amount of electrolyte (aluminum chloride / 1-ethyl-3-methylimidazolium chloride, with a molar ratio of 1.8:1) to obtain the aluminum battery of Comparative Example 1.

[0037] Example 1

[0038] The aluminum battery of Example 1 is similar to the aluminum battery of Comparative Example 1, but differs as follows. The active material of the positive electrode coating layer is a conductive carbon material (graphene, 80 wt% by weight in the coating layer, with a layer count of 3 or less), a water-soluble conductive polymer (a polymer mixture of poly(3,4-dioxyethylthiophene) and polystyrene sulfonic acid (molar ratio 1:1.6), 8 wt% by weight in the coating layer, WED-SM, a product of Tairitsu Polymer Industries Co., Ltd.), the weight ratio of the conductive carbon material to the water-soluble conductive polymer is 10:1, and the auxiliary agent (12 wt% by weight in the coating layer) is a neutralizer (triethanolamine, UNI-ONWARD Corp.), a defoamer (150N, the main active ingredient is polyacrylate, AN FONG DEVELOPMENT CO., LTD.), a thickener, a solvent (ethylene glycol and water), and an adhesive (carboxymethyl cellulose (CMC) / styrene-butadiene rubber). The positive electrode coating layer is made of a mixture of the active material and additives (rubber, SBR) in a ratio of 1:4, with a weight ratio of 90:1. The positive electrode coating layer is manufactured using the above-mentioned components. The water-soluble conductive polymer (characteristics shown in Table 1) is neutralized with a neutralizing agent to reach the desired pH (e.g., between 7 and 8). A solvent is then added (the weight ratio of the water-soluble conductive polymer can be 10 wt%). A 0.1 wt% antifoaming agent is added to the total solution, followed by filtration (filter pore size can be 1 micron). A 1.5 wt% thickener is then added to the total solution, followed by stirring (at a rotation speed of 600 rpm or higher) to thicken the mixture to a 200 mesh (not penetrating the screen), yielding a first slurry (characteristics shown in Table 2). A 16 wt% conductive carbon material is then added to produce a second slurry (characteristics shown in Table 3). The first and second slurries were then mixed at a stirring speed of 600 rpm for 30 minutes, and after mixing was completed, a raw material (properties are shown in Table 4) was formed. The raw material was then mixed with an adhesive to form the desired coating layer.

[0039] [Table 1]

[0040] [Table 2]

[0041] [Table 3]

[0042] [Table 4]

[0043] <Comparative Example 2>

[0044] A coating layer (materials: graphite, conductive carbon black, adhesive (Carboxymethyl Cellulose (CMC) / Styrene-Butadiene Rubber (SBR)), ratio: 1:4, and weight ratio of each component: 90:2:8) was formed on polyethylene terephthalate (PET) to obtain a polyethylene terephthalate coating film of Comparative Example 2.

[0045] <Example 2>

[0046] A coating layer (active material: conductive carbon material (graphene, weight ratio in the coating layer: 80 wt%), water-soluble conductive polymer (polymer mixture of poly(3,4-dioxyethylthiophene) and polystyrene sulfonic acid (molar ratio: 1:1.6), weight ratio in the coating layer: 8 wt%), and auxiliary agent (weight ratio in the coating layer: 12 wt%), including a neutralizer (triethanolamine), thickener (VIS4), solvent (ethylene glycol and water), and adhesive (carboxymethyl cellulose (CMC) / styrene-butadiene rubber (SBR), ratio: 1:4)) was formed on polyethylene terephthalate, and the weight ratio of the active material to the auxiliary agent was 90:1, to obtain a polyethylene terephthalate coating film of Example 2.

[0047] FIG. 1 is a schematic diagram showing the results of a life test for Example 1 and Comparative Example 1. FIG. 2 is a schematic diagram showing the results of a durability test for Example 2 and Comparative Example 2. FIG. 1 shows a charge / discharge test of an aluminum battery using a microcurrent charge / discharge machine (TPT-B1HCL050B) manufactured by Think Power Technology Co., Ltd., to measure the maximum life (number of charge / discharge cycles) at a charge / discharge rate of 3C. FIG. 2 shows the measurement of the resistance of the polyethylene terephthalate coating film using an LCR tester (HIOKI LCR3536) manufactured by Hioki E.E. Corporation. It should be noted that the structure in FIG. 2 was used only for the durability test and is not the positive electrode structure of the present invention.

[0048] The test results are shown in Figures 1 and 2, and the conclusions are as follows: From the results in Figure 1, it can be seen that the composite material of Example 1 has higher structural strength than graphite, which effectively improves operational stability and reduces material collapse; therefore, the aluminum battery of Example 1 has a longer cycle life than the aluminum battery of Comparative Example 1. As shown in Figure 2, Example 2 has lower resistance, and this composite material can effectively improve conductivity and reduce resistance due to the high conductivity of the conductive carbon material (graphene) and the defect modification by the water-soluble conductive polymer.

[0049] In summary, the positive electrode coating material of the present invention contains at least five layers of a conductive carbon material and a water-soluble conductive polymer. The combination of the two enhances the structural stability of the positive electrode, and these materials are conductive, thereby improving the lifespan of aluminum batteries and maintaining better conductivity. Meanwhile, during the manufacturing process, the water-soluble conductive polymer can be used as a dispersion system in water (no organic solvents are used), which has the effect of protecting the environment.

[0050] Although the present invention has been disclosed by the above embodiments, they are not intended to limit the present invention. Those skilled in the art can make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope of the attached patent application. [Industrial Applicability]

[0051] The present invention provides an aluminum battery that can be applied to the aluminum battery field.

Claims

1. a positive electrode including a metal substrate and a coating layer, the coating layer being provided on the metal substrate, and the material of the coating layer including a conductive carbon material and a water-soluble conductive polymer in a number of layers of 5 or less; a negative electrode; a separator provided between the positive electrode and the negative electrode; an electrolyte impregnated in the separator, the positive electrode, and the negative electrode.

2. 2. The aluminum battery according to claim 1, wherein the weight ratio of the conductive carbon material to the water-soluble conductive polymer is between 10:1 and 10:

5.

3. the conductive carbon material includes graphene; 2. The aluminum battery of claim 1, wherein the water-soluble conductive polymer comprises a polymer mixture of poly(3,4-dioxyethylthiophene) and polystyrene sulfonic acid.

4. 4. The aluminum battery according to claim 3, wherein the molar ratio of the poly(3,4-dioxyethylthiophene) to the polystyrene sulfonic acid is between 1:1.6 and 1:

5.

5. 2. The aluminum battery according to claim 1, wherein the weight ratio of the conductive carbon material in the coating layer is between 65 wt % and 80 wt %.

6. 2. The aluminum battery according to claim 1, wherein the weight ratio of the water-soluble conductive polymer in the coating layer is between 8 wt % and 13 wt %.

7. The coating layer further comprises an auxiliary agent, 2. The aluminum battery according to claim 1, wherein the auxiliary agent comprises a neutralizing agent, an antifoaming agent, a thickener, a solvent, and an adhesive, or a combination thereof.

8. 8. The aluminum battery according to claim 7, wherein the weight ratio of the auxiliary agent in the coating layer is between 7 wt % and 27 wt %.

9. 8. The aluminum battery of claim 7, wherein the adhesive is a non-conductive polymer.

10. 2. The aluminum battery of claim 1, wherein the material of the metal substrate comprises titanium, nickel, or a combination thereof.

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