Aluminum battery

Abstract

An aluminum battery includes a positive electrode, a negative electrode, a separator, and an electrolyte. The positive electrode includes a metal substrate and a coating. The coating is disposed on the metal substrate, and the coating material includes conductive carbon material with five or fewer layers and a water-soluble conductive polymer. The separator is disposed between the positive and negative electrodes. The electrolyte is impregnated in the separator, the positive electrode, and the negative electrode.

Description

Technical Field

[0001] This invention relates to an aluminum battery. Prior Technology

[0002] Based on the mechanism of the positive electrode of aluminum batteries to accommodate / interpenetrate living organisms and the requirements for conductivity, high conductivity materials with layered structures (such as graphite) are often selected. However, with the continuous charging and discharging process, the layered structure is prone to expansion and collapse due to its structural defects, which leads to a reduction in lifespan. Summary of the Invention

[0003] This invention provides an aluminum battery that can improve lifespan and maintain better conductivity.

[0004] An 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. The coating is disposed on the metal substrate, and the coating material includes conductive carbon material with five or fewer layers and a water-soluble conductive polymer. The separator is disposed between the positive and negative electrodes. The electrolyte is impregnated in the separator, the positive electrode, and the negative electrode.

[0005] In one embodiment of the present invention, the weight ratio between the above-mentioned conductive carbon material and the water-soluble conductive polymer is between 10:1 and 10:5.

[0006] In one embodiment of the present invention, the conductive carbon material mentioned above includes graphene, and the water-soluble conductive polymer includes a polymer mixture of poly(3,4-dioxyethylthiophene) and polystyrene sulfonic acid.

[0007] In one embodiment of the present invention, the molar ratio between the above-mentioned poly(3,4-dioxyethylthiophene) and polystyrene sulfonic acid is between 1:1.6 and 1:5.

[0008] In one embodiment of the present invention, the weight ratio of the above-mentioned conductive carbon material in the coating is between 65wt% and 80wt%.

[0009] In one embodiment of the present invention, the weight ratio of the above-mentioned water-soluble conductive polymer in the coating is between 8 wt% and 13 wt%.

[0010] In one embodiment of the present invention, the coating further includes additives, including neutralizers, defoamers, thickeners, solvents and adhesives, or combinations thereof.

[0011] In one embodiment of the present invention, the above-mentioned additives are present in a weight ratio between 7 wt% and 27 wt% in the coating.

[0012] In one embodiment of the present invention, the adhesive is a non-conductive polymer.

[0013] In one embodiment of the present invention, the material of the metal substrate includes titanium, nickel, or a combination thereof.

[0014] Based on the above, the coating material of the positive electrode of the present invention includes at least five layers of conductive carbon material and water-soluble conductive polymer. The combination of the two increases the structural stability of the positive electrode, and these materials have conductivity, thus improving the life of aluminum battery and maintaining better conductivity.

[0015] To make the above features and advantages of the present invention more apparent and understandable, specific embodiments are described below in conjunction with the accompanying drawings for detailed explanation. Simple Explanation of the Diagram

[0016] Figure 1 is a schematic diagram of the results of the lifetime test for the embodiment and the comparative example. Figure 2 is a schematic diagram of the resistance test results of the embodiment and the comparative example. Implementation

[0017] To facilitate a better understanding of the invention, specific embodiments are provided below as examples of how the invention can be practiced. For clarity, numerous practical details will be described in the following description. However, it should be understood that these practical details should not be construed as limiting the invention. In other words, these practical details are not essential in some embodiments of the invention.

[0018] To clearly illustrate the present invention, known aluminum battery design rules are omitted herein. Anyone skilled in the art can design according to actual needs without departing from the spirit and scope of the present invention.

[0019] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0020] Unless otherwise stated, the term "between" used in this specification to define numerical ranges is intended to cover the range equal to and between the endpoint 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.

[0021] 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 and negative electrodes, and the electrolyte is impregnated in the separator, the positive electrode, and the negative electrode. The positive electrode includes a metal substrate and a coating disposed thereon. Here, the positive electrode, negative electrode, separator, and electrolyte can be configured in a manner suitable for use in the field of aluminum batteries, and the present invention is not limited thereto.

[0022] Furthermore, the aforementioned coating material includes at least five layers of conductive carbon material and a water-soluble conductive polymer. This combination increases the structural stability of the positive electrode, and the materials themselves are conductive, thus improving the lifespan of the aluminum battery and maintaining better conductivity. Moreover, when the conductive carbon material has too many layers (e.g., graphite with ten or more layers), the polymer material cannot penetrate between its layered structure without additional energy. This invention selects a suitable number of layers (e.g., three to five layers) that allows the polymer material to penetrate more easily, thereby achieving a better penetration effect and effectively repairing structural defects in the conductive carbon material. Here, the layered structure can extend in a first direction, and the polymer material can extend in a second direction perpendicular to the first direction, thus creating a stable, interwoven structure. However, this invention is not limited to this.

[0023] On the other hand, during the manufacturing process, water-soluble conductive polymers can use water as a dispersion system, meaning that water-soluble polymers can dissolve in water without producing precipitation, thus having an environmentally friendly effect. For example, the positive electrode coating of the present invention does not contain organic solvents after drying, and can be considered an environmentally friendly electrode, but the present invention is not limited thereto. Here, in the aforementioned manufacturing process, the solid content of the slurry is less than or equal to 30 wt% (the total weight of solids in the slurry divided by the total weight of the slurry), so that it can be reliably coated onto the metal substrate with fluidity. In one embodiment, the solid content of the slurry is, for example, 16 wt%, which has better operability, but the present invention is not limited thereto.

[0024] In some embodiments, the weight ratio between the conductive carbon material and the water-soluble conductive polymer is between 10:1 and 10:5 (e.g., 10:1), and / or the molar ratio between poly(3,4-dioxyethylthiophene) and polystyrene sulfonic acid is between 1:1.6 and 1:5. This allows the water-soluble conductive polymer to more reliably penetrate between the layers of the conductive carbon material, further improving structural stability. However, the invention is not limited to this. Here, a suitable molar ratio of water-soluble conductive polymer can be selected based on the interlayer spacing of the conductive carbon material.

[0025] In some embodiments, the conductive carbon material includes graphene with high specific surface area, conductivity and structural strength, which can avoid the problem of high resistance causing the performance of aluminum batteries to degrade. In order to improve the structural defects such as poor stacking or irregularity in the graphene exfoliated sheet material, a water-soluble conductive polymer including a polymer mixture of poly(3,4-dioxyethylthiophene) and polystyrene sulfonic acid (PEDOT:PSS) is introduced to repair the aforementioned defects. In this way, the two can achieve better life performance through synergistic effect. However, the present invention is not limited to this. For example, the polymer mixture of poly(3,4-dioxyethylthiophene) and polystyrene sulfonic acid is WED-SM, a commercial product of Dali Polymer Industry.

[0026] In some embodiments, the weight percentage of conductive carbon material in the coating is between 65 wt% and 80 wt%, and the weight percentage of water-soluble conductive polymer in the coating is between 8 wt% and 13 wt%, but the present invention is not limited thereto.

[0027] In some embodiments, the coating further includes additives, wherein the additives include neutralizers, defoamers, thickeners, solvents and adhesives or combinations thereof, and the weight percentage of the additives in the coating is between 7 wt% and 27 wt%, but the invention is not limited thereto.

[0028] In some embodiments, the adhesive is a non-conductive polymer, such as sodium carboxymethyl cellulose (CMC) / styrene-butadiene rubber (SBR), the neutralizer may be 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, an oil dispersion whose main active ingredient is a renewable polymer.

[0029] In some embodiments, the material of the metal substrate includes titanium, nickel, or a combination thereof, but the invention is not limited thereto.

[0030] In some embodiments, the thickness of the metal substrate is between 30 micrometers (µm) and 100 µm, and the thickness of the coating is between 50 µm and 70 µm, but the present invention is not limited thereto.

[0031] In some embodiments, the electrolyte includes aluminum halide, ionic liquid, or a combination thereof, wherein the aluminum halide includes aluminum chloride (AlCl3) and the ionic liquid includes 1-ethyl-3-methylimidazolium chloride, but the invention is not limited thereto.

[0032] In some embodiments, the negative electrode material includes aluminum foil, and the separator material includes glass fiber or the like, wherein the thickness of the negative electrode is between 30 μm and 100 μm, and the thickness of the separator is between 30 μm and 350 μm, but the present invention is not limited thereto.

[0033] The effects of the aluminum battery of the present invention will be described in more detail below with reference to embodiments and comparative examples. Furthermore, although the following embodiments are described, the details of the materials used and the process, etc., may be appropriately changed without departing from the scope of the present invention, and the present invention should not be interpreted as limiting based on the embodiments described below.

[0034] <Comparative Example 1>

[0035] A negative electrode (0.05 mm thick, Φ14 mm) was obtained by cutting aluminum foil. A positive electrode was prepared by forming a coating (the material is graphite, conductive carbon black and adhesive (carboxymethyl cellulose (CMC) / styrene-butadiene rubber (SBR) in a ratio of 1:4, with the weight ratio of each component being 90:2:8)) on nickel foil (0.03 mm thick, Φ15 mm). Then, the negative electrode, separator and positive electrode were arranged in that order and placed in a battery rich in 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.

[0036] <Example 1>

[0037] The aluminum battery of Example 1 is similar to the aluminum battery of Comparative Example 1, except that: the active material of the positive electrode coating is conductive carbon material (graphene, with a weight ratio of 80 wt% in the coating, and fewer than three layers), water-soluble conductive polymer (a polymer mixture of poly(3,4-dioxyethylthiophene) and polystyrene sulfonic acid (molar ratio of 1:1.6), with a weight ratio of 8 wt% in the coating, WED-SM, a product of Dali Polymer Industry), the weight ratio of conductive carbon material to water-soluble conductive polymer is 10:1, and additives (with a weight ratio of 12 wt% in the coating). The additives consist of a neutralizing agent (triethanolamine, Yuhe Trading Co., Ltd.), a defoamer (150N, with polyacrylate as the main active ingredient, Anfeng Industrial Co., Ltd.), a thickener, a solvent (ethylene glycol and water), and an adhesive (carboxymethyl cellulose (CMC) / styrene-butadiene rubber). The composition consists of a rubber (SBR) ratio of 1:4, and the weight ratio of active material to additives is 90:1. Here, the method for preparing the positive electrode coating uses the aforementioned components to neutralize the water-soluble conductive polymer (characteristics shown in Table 1) with a neutralizing agent to achieve the desired pH value (e.g., between 7 and 8). Next, a solvent (with a weight ratio of 10 wt% to the water-soluble conductive polymer) is added, and an antifoaming agent is added at 0.1 wt% of the total solution before filtration (the filtration pore size can be 1 micrometer). Then, a thickener is added at 1.5 wt% of the total solution, and the mixture is stirred (at a speed greater than 600 rpm) to thicken to 200 mesh (not penetrating the screen), which is the first slurry (characteristics shown in Table 2). On the other hand, conductive carbon material is added at 16 wt% as the second slurry (characteristics shown in Table 3). The first slurry and the second slurry are then mixed at a stirring speed of 600 rpm for 30 minutes. After mixing, the raw material is formed (the properties are shown in Table 4). Then, the aforementioned raw material is mixed with the adhesive to form the desired coating.

[0038] Table 1 color Dark blue Solid content (wt%) 1.21 Viscosity (cP) 19.2 Conductivity (S / cm) 511 Particle size (nm) 15.21

[0039] Table 2 color Dark blue Solid content (wt%) 0.88 Viscosity (cP) 600 Impedance (ohms) 6.6

[0040] Table 3 color gray-black Solid content (wt%) 17.0 Viscosity (cP) 5200

[0041] Table 4 color black Solid content (wt%) 16.9 Viscosity (cP) 5200 Impedance (ohms) 0.7

[0042] <Comparative Example 2>

[0043] A coating was formed on polyethylene terephthalate (PET) (the materials being graphite, conductive carbon black, and an adhesive (carboxymethyl cellulose (CMC) / styrene-butadiene rubber (SBR) in a ratio of 1:4), with the weight ratio of each component being 90:2:8), to obtain the polyethylene terephthalate coating of Comparative Example 2.

[0044] <Example 2>

[0045] A coating was formed on polyethylene terephthalate (the active material was conductive carbon material (graphene, in the weight ratio of 80 wt%), a water-soluble conductive polymer (a polymer mixture of poly(3,4-dioxyethylthiophene) and polystyrene sulfonic acid (molar ratio of 1:1.6, in the weight ratio of 8 wt%), and additives (in the weight ratio of 12 wt%), such as neutralizer (triethanolamine), thickener (VIS4), solvent (ethylene glycol and water), and adhesive (carboxymethyl cellulose (CMC) / styrene-butadiene rubber (SBR) in a ratio of 1:4), etc., with the weight ratio of active material to additives being 90:1, to obtain the polyethylene terephthalate coating of Example 2.

[0046] Figure 1 is a schematic diagram of the life test results for Example 1 and Comparative Example 1. Figure 2 is a schematic diagram of the resistance test results for Example 2 and Comparative Example 2. Figure 1 shows the charge-discharge test of the aluminum battery using a micro-current charge-discharge machine (TPT-B1HCL050B) from Shinco Electric Technology Co., Ltd., measuring the maximum lifespan (number of charge-discharge cycles) at a 3C charge-discharge rate. Figure 2 shows the measurement of the resistance of the polyethylene terephthalate coating using an LCR meter (HIOKI LCR3536) from HIOKI Electric Co., Ltd. It should be noted that the structure in Figure 2 is only for resistance testing and is not the positive electrode structure of this invention.

[0047] The test results are shown in Figures 1 and 2, and the conclusions are as follows. As shown in Figure 1, the composite material in Example 1 has higher structural strength than graphite, which effectively improves operational stability and reduces material breakage. Therefore, the aluminum battery in Example 1 has a longer cycle life than the aluminum battery in Comparative Example 1. As shown in Figure 2, Example 2 has lower resistance. This composite material, due to the high conductivity of conductive carbon material (graphene) and the modification of defects by water-soluble conductive polymers, effectively improves conductivity and thus reduces resistance.

[0048] In summary, the coating material of the positive electrode of the present invention comprises at least five layers of conductive carbon material and water-soluble conductive polymer. This combination increases the structural stability of the positive electrode, and since these materials are conductive, they can improve the lifespan of aluminum batteries and maintain better conductivity. Furthermore, during the manufacturing process, water can be used as the dispersion system for the water-soluble conductive polymer (without using organic solvents), thus offering environmental benefits.

[0049] Although the present invention has been disclosed above by way of embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make some modifications and refinements 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 appended claims.

[0050] none.

Claims

1. An aluminum battery, comprising: A positive electrode includes a metal substrate and a coating, wherein the coating is disposed on the metal substrate, and the coating material comprises conductive carbon material with five or fewer layers and a water-soluble conductive polymer, wherein the weight ratio between the conductive carbon material and the water-soluble conductive polymer is between 10:1 and 10:5, and the conductive carbon material extends in a first direction, and the water-soluble conductive polymer extends in a second direction perpendicular to the first direction; a negative electrode; a separator disposed between the positive electrode and the negative electrode; and an electrolyte impregnated in the separator, the positive electrode, and the negative electrode.

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

3. The aluminum battery as claimed in claim 2, wherein the molar ratio between the poly(3,4-dioxyethylthiophene) and the polystyrene sulfonic acid is between 1:1.6 and 1:

5.

4. The aluminum battery as claimed in claim 1, wherein the conductive carbon material in the coating comprises between 65 wt% and 80 wt% by weight.

5. The aluminum battery as claimed in claim 1, wherein the water-soluble conductive polymer in the coating comprises between 8 wt% and 13 wt% by weight.

6. The aluminum battery as claimed in claim 1, wherein the coating further comprises additives, wherein the additives include neutralizers, defoamers, thickeners, solvents and adhesives, or combinations thereof.

7. The aluminum battery as claimed in claim 6, wherein the additive is present in the coating at a weight percentage between 7 wt% and 27 wt%.

8. The aluminum battery as claimed in claim 6, wherein the adhesive is a non-conductive polymer.

9. The aluminum battery as claimed in claim 1, wherein the material of the metal substrate includes titanium, nickel, or a combination thereof.

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