Aluminum battery

Abstract

PURPOSE: To provide an aluminum battery capable of effectively improving service life and maintaining excellent performance.SOLUTION: An 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 separator, the positive electrode, and the negative electrode are impregnated with the electrolyte. The electrolyte contains aluminum halide, ionic liquid, and an additive, and the additive contains an isocyanate-based compound.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an aluminum battery.

Background Art

[0002] In the manufacturing process of an aluminum battery, external moisture easily penetrates into the electrolyte, so harmful gases are likely to be generated during the charge and discharge process of the aluminum battery, resulting in performance degradation (for example, a decrease in Coulomb efficiency). Furthermore, the power storage reaction of an aluminum battery is the precipitation and dissolution of aluminum. However, when the rates of aluminum precipitation and dissolution cannot be balanced, or when aluminum dendrite forms are generated due to the accumulation of charges on the electrode surface, the service life will decrease in either case.

Summary of the Invention

Problems to be Solved by the Invention

[0003] Harmful gases are likely to be generated during the charge and discharge process of an aluminum battery, resulting in performance degradation (for example, a decrease in Coulomb efficiency). On the other hand, the power storage reaction of an aluminum battery is the precipitation and dissolution of aluminum. However, when the rates of aluminum precipitation and dissolution cannot be balanced, or when aluminum dendrite forms are generated due to the accumulation of charges on the electrode surface, the service life will decrease in either case.

Means for Solving the Problems

[0004] The present invention provides an aluminum battery that can effectively improve the service life and maintain excellent performance at the same time.

[0005] The aluminum battery of the present invention includes a positive electrode, a negative electrode, a separator, and an electrolyte. The separator is installed between the positive electrode and the negative electrode. The electrolyte is impregnated in the separator, the positive electrode, and the negative electrode. The electrolyte contains aluminum halide, an ionic liquid, and an additive, and the additive contains an isocyanate-based compound.

[0006] In one embodiment of the present invention, the isocyanate compound described above further comprises an acrylic acid functional group.

[0007] In one embodiment of the present invention, the weight ratio of the aluminum halide, ionic liquid, and additive in the electrolyte is, in descending order, aluminum halide, ionic liquid, and additive.

[0008] In one embodiment of the present invention, the weight ratio of the above-mentioned additive in the electrolyte is 0.2 wt% or more.

[0009] In one embodiment of the present invention, the weight ratio of the aluminum halide in the electrolyte is between 49 wt% and 65 wt%.

[0010] In one embodiment of the present invention, the weight ratio of the above-mentioned ionic liquid in the electrolyte is between 35 wt% and 51 wt%.

[0011] In one embodiment of the present invention, the total weight ratio of the aluminum halide, ionic liquid, and additives in the electrolyte is 100 wt%.

[0012] In one embodiment of the present invention, the aluminum halide described above includes aluminum chloride, and the ionic liquid includes 1-ethyl-3-methylimidazolium chloride.

[0013] In one embodiment of the present invention, the isocyanate compound described above is arranged to form an amine compound during the operation of the aluminum battery.

[0014] In one embodiment of the present invention, the above-described amine compound is adsorbed onto the surface of the negative electrode during operation of the aluminum battery. [Effects of the Invention]

[0015] As described above, the present invention introduces an electrolyte containing an isocyanate compound into the design of an aluminum battery. By reacting the isocyanate functional group with water in the electrolyte, the water content in the electrolyte is reduced, suppressing the generation of harmful gases, and the aluminum dissolution reaction in the negative electrode is promoted, thereby suppressing the formation of aluminum dendrites. In this way, the service life can be effectively improved while maintaining excellent performance.

[0016] To provide a clearer understanding of the above-mentioned features and advantages of the present invention, embodiments are described below in detail in conjunction with the accompanying drawings. [Brief explanation of the drawing]

[0017] [Figure 1] This is a schematic diagram showing the results of the moisture content test for the examples and comparative examples. [Figure 2] This is a schematic diagram showing the results of the active substance test in the example. [Figure 3] This is a schematic diagram showing the results of the mean Coulomb efficiency test for the examples and comparative examples. [Figure 4] This is a schematic diagram showing the results of the life test for the examples and comparative examples. [Figure 5] This is a schematic diagram of a portion of an electrochemical apparatus for performing cycle charge-discharge experiments in the present invention. [Figure 6] This is a schematic diagram showing the results of the corrosion test for Comparative Example 1. [Figure 7] This is a schematic diagram showing the results of the corrosion test in Example 2. [Modes for carrying out the invention]

[0018] To make it easier to understand the content of the present invention, embodiments are given below to show that the present invention is an example that can be surely implemented. For the sake of clear explanation, many practical details are also explained in the following description. However, it should be understood that these practical details are not for limiting the present invention. That is, in some embodiments of the present invention, these practical details are not essential.

[0019] To clearly explain the present invention, the description of known aluminum battery design rules is omitted in the text. However, those with ordinary knowledge in the technical field can perform the design according to actual needs without departing from the spirit and scope of the present invention.

[0020] The present invention will be further comprehensively described while referring to the drawings of the present embodiment. However, the present invention can be embodied in various different forms and should not be limited to the embodiments described in the text. The thickness, dimensions, or sizes of layers and regions in the drawings are exaggerated for clarity. The same or similar reference numerals indicate the same or similar elements and will not be repeatedly explained in the following paragraphs.

[0021] Unless otherwise defined, all technical terms (including technical and scientific terms) used in the text have the same meaning as those usually understood by a person having ordinary knowledge in the field to which the present invention pertains.

[0022] Unless otherwise explained, the term "between ~" used to define a numerical range in this specification includes values equal to the described endpoint values and the range between the described endpoint values. For example, when a dimension range is between a first numerical value and a second numerical value, it means that the dimension range may include the first numerical value, the second numerical value, and any value between the first numerical value and the second numerical value.

[0023] First, it should be explained that this text applies to situations where the electrolyte of an aluminum battery contains a small amount of water. Since this small amount of water originates from the external environment during the manufacturing process, the weight of the water may be ignored when describing the total weight of the electrolyte below.

[0024] In this embodiment, the aluminum battery comprises a positive electrode, a negative electrode, a separator, and an electrolyte, the separator being placed between the positive and negative electrodes, and the electrolyte impregnating the separator, the positive electrode, and the negative electrode. Herein, the positive electrode, the negative electrode, the separator, and the electrolyte can be arranged relative to each other in a suitable manner known in the field of aluminum batteries, but the present invention is not limited thereto.

[0025] Furthermore, the electrolyte contains aluminum halide, an ionic liquid, and an additive, the additive containing an isocyanate compound. Thus, this embodiment introduces an electrolyte containing an isocyanate compound into the design of an aluminum battery, and the reaction between the isocyanate functional group and the water in the electrolyte reduces the water content in the electrolyte, suppressing the generation of harmful gases and promoting the dissolution aluminum reaction at the negative electrode, thereby suppressing the formation of aluminum dendrites. In this way, the service life can be effectively improved while maintaining excellent performance. It should be noted that, since the present invention is an aluminum battery design, the electrolyte uses aluminum halide and an ionic liquid that can generate active substances such as aluminum ions, and these are not electrolyte components selected for other types of batteries.

[0026] To further explain, the isocyanate functional groups are positioned to form amine compounds during the operation of the aluminum battery. In other words, the isocyanate functional groups react with water in the electrolyte to produce amine compounds, thereby effectively reducing the water content and suppressing the generation of gases that adversely affect aluminum batteries, such as hydrogen chloride (HCl). Furthermore, the aforementioned amine compounds, due to their lone pair of electrons on their nitrogen (Lewis base), adsorb onto the surface of the negative electrode during the operation (e.g., discharge) of the aluminum on the negative electrode surface. 3+ It reacts with Lewis acid to form a metal complex, thereby improving the dissolving ability of aluminum. Therefore, it can effectively suppress the dendrite formation of aluminum during the cycle charge-discharge process of aluminum batteries, extending battery life.

[0027] In some embodiments, carbon dioxide is formed during the reaction between the isocyanate functional group and the electrolyte; however, this gas is not harmful as it does not adversely affect the aluminum battery. The present invention is not limited thereto.

[0028] In some embodiments, the isocyanate compound further includes an acrylic acid functional group, and the isocyanate compound does not include a benzene ring functional group. For example, the isocyanate compound includes 2-isocyanate ethyl acrylate (C6H7NO3). Therefore, the resulting amine compound may be an isocyanate group (C5H4NO2, chemical formula HN=C=O, chemical structural formula see the chemical formula below), but the present invention is not limited thereto. The isocyanate compound may be other analogues of 2-isocyanate ethyl acrylate, and any compound having an isocyanate functional group and capable of reacting with water in the electrolyte to produce an amine compound is included within the scope of protection of the present invention. Here, the amine compound differs depending on the type of isocyanate compound. [ka]

[0029] In some embodiments, the weight ratio of aluminum halide, ionic liquid, and additive in the electrolyte is, in descending order, aluminum halide, ionic liquid, and additive, but the present invention is not limited thereto.

[0030] In some embodiments, the weight ratio of the additive in the electrolyte is greater than or equal to 0.2 wt%, more preferably less than or equal to 5 wt%, thereby preventing the aluminum battery from becoming inoperable due to the action of the additive, but the present invention is not limited thereto.

[0031] In some embodiments, the weight ratio of aluminum halide in the electrolyte is between 49 wt% and 65 wt%, but the present invention is not limited thereto.

[0032] In some embodiments, the weight ratio of the ionic liquid in the electrolyte is between 35 wt% and 51 wt%, but the present invention is not limited thereto.

[0033] In some embodiments, the total weight ratio of aluminum halide, ionic liquid, and additives in the electrolyte is 100 wt%. That is, the electrolyte consists only of aluminum halide, ionic liquid, and additives including isocyanate compounds. Here, the weight of trace amounts of water in the electrolyte may be ignored.

[0034] In some embodiments, the aluminum halide includes aluminum chloride (AlCl3), and the ionic liquid includes 1-ethyl-3-methylimidazolium chloride. Herein, since the aforementioned ionic liquid is a hydrophilic ionic liquid, a more significant improvement effect can be obtained when using the aforementioned ionic liquid or an analogue thereof, but the present invention is not limited thereto.

[0035] In some embodiments, the negative electrode material more preferably includes aluminum foil, as a synergistic effect between an additive containing an isocyanate compound and aluminum foil can be obtained; however, the present invention is not limited thereto.

[0036] In some embodiments, the thickness of the negative electrode is between 10 micrometers and 100 micrometers, but the present invention is not limited thereto.

[0037] In some embodiments, the positive electrode material comprises a graphite-carbon material, a conductive additive, and an adhesive, wherein the conductive additive comprises conductive carbon black (super P), and the adhesive comprises carboxymethylcellulose, styrene-butadiene rubber, or a combination thereof, but the present invention is not limited thereto.

[0038] In some embodiments, the thickness of the positive electrode is between 100 micrometers and 300 micrometers, but the present invention is not limited thereto.

[0039] The effects that the aluminum battery of the present invention can achieve will be described in more detail below with reference to Examples 1 to 5 and Comparative Example 1. While Examples 1 to 5 will be described below, the details of the materials used, the processes, etc., may be appropriately modified without departing from the scope of the present invention, and the present invention should not be interpreted as being limited by Examples 1 to 5 described below.

[0040] <Example 1>

[0041] An aluminum foil (0.05 mm thick) was used as the negative electrode, and a graphite slurry was applied to a nickel foil (0.05 mm thick) to prepare the positive electrode. Next, glass fibers were provided as a separator. Then, the negative electrode, separator, and positive electrode were arranged in that order, and an electrolyte consisting of aluminum chloride (aluminum halide), 1-ethyl-3-methylimidazolium chloride (ionic liquid), and isocyanate ethyl acrylate (additive) was injected and sealed to obtain the aluminum battery of Example 1. Here, the weight ratio of aluminum chloride in the electrolyte was 58.97 wt%, the weight ratio of 1-ethyl-3-methylimidazolium chloride (EMIC) in the electrolyte was 36.03 wt%, and the weight ratio of isocyanate ethyl acrylate in the electrolyte was 5 wt%.

[0042] <Example 2>

[0043] The aluminum battery of Example 2 is similar to the aluminum battery of Example 1, but the difference is that the weight ratio of aluminum chloride in the electrolyte was 61.45 wt%, the weight ratio of 1-ethyl-3-methylimidazolium chloride (EMIC) in the electrolyte was 37.54 wt%, and the weight ratio of isocyanate ethyl acrylate in the electrolyte was 1 wt%.

[0044] <Example 3>

[0045] The aluminum battery of Example 3 is similar to the aluminum battery of Example 1, but the difference is that the weight ratio of aluminum chloride in the electrolyte was 61.6 wt%, the weight ratio of 1-ethyl-3-methylimidazolium chloride in the electrolyte was 37.6 wt%, and the weight ratio of isocyanate ethyl acrylate in the electrolyte was 0.8 wt%.

[0046] <Example 4>

[0047] The aluminum battery of Example 4 is similar to the aluminum battery of Example 1, but the difference is that the weight ratio of aluminum chloride in the electrolyte was 61.8 wt%, the weight ratio of 1-ethyl-3-methylimidazolium chloride in the electrolyte was 37.6 wt%, and the weight ratio of isocyanate ethyl acrylate in the electrolyte was 0.6 wt%.

[0048] <Example 5>

[0049] The aluminum battery of Example 5 is similar to the aluminum battery of Example 1, but the difference is that the weight ratio of aluminum chloride in the electrolyte was 61.9 wt%, the weight ratio of 1-ethyl-3-methylimidazolium chloride in the electrolyte was 37.8 wt%, and the weight ratio of isocyanate ethyl acrylate in the electrolyte was 0.4 wt%.

[0050] <Example 6>

[0051] The aluminum battery of Example 6 is similar to the aluminum battery of Example 1, but the difference is that the weight ratio of aluminum chloride in the electrolyte was 62 wt%, the weight ratio of 1-ethyl-3-methylimidazolium chloride in the electrolyte was 37.8 wt%, and the weight ratio of isocyanate ethyl acrylate in the electrolyte was 0.2 wt%.

[0052] <Comparative Example 1>

[0053] The aluminum battery of Comparative Example 1 was similar to the aluminum battery of Example 1, but differed in that the electrolyte consisted of aluminum chloride (aluminum halide) and 1-ethyl-3-methylimidazolium chloride (ionic liquid), and did not contain isocyanate compound additives. The weight ratio of aluminum chloride in the electrolyte was 62 wt%, and the weight ratio of 1-ethyl-3-methylimidazolium chloride in the electrolyte was 38 wt%.

[0054] Tests were conducted on Examples 1 to 6 and Comparative Example 1, and the results are shown in Figures 1 to 7. The conclusions are as follows.

[0055] Figure 1 shows the results of the moisture content test for Examples 1 and 2 and Comparative Example 1, where the moisture content of the electrolyte was measured using a Coulomb moisture meter. As can be seen from the results in Figure 1, the average moisture content of Examples 1 and 2 decreased by 62.6 to 89.5 ppm compared to Comparative Example 1, indicating that the isocyanate functional group indeed reacted with the water in the electrolyte to produce an amine compound (C5H4NO2) and CO2, thereby reducing the moisture content.

[0056] Figure 2 shows the results of the active substance tests for Examples 2-6, using Raman spectroscopy to determine the activity of AlCl4 - Al2Cl7 - ,EMI + This analysis examined whether the signals of active substances such as [specific substances] had disappeared. As can be seen from the results in Figure 2, within the range of addition ratios in Examples 2 to 6, none of them affected the concentration of active substances in the electrolyte. In other words, within the range of addition ratios in Examples 2 to 6, all aluminum batteries can operate normally.

[0057] Figure 3 is a schematic diagram showing the results of the Coulomb efficiency test for Examples 1, 2, and 4 and Comparative Example 1. Figure 4 is a schematic diagram showing the results of the life test for Examples 1, 2, and 4 and Comparative Example 1. Figure 5 is a schematic diagram of a portion of the electrochemical apparatus used in the cycle charge-discharge experiment of the present invention. Here, the aluminum battery is a soft-pack aluminum battery, and the spacing between the negative electrode 110, positive electrode 120, and electrolyte 130 of the aluminum battery was fixed by the fixing member 102 (e.g., a glass slide) in Figure 5, fixing the positions of the negative electrode 110 and positive electrode 120, and the test was performed at a charge-discharge rate of 4C. As can be seen from the results in Figures 4 and 5, Examples 1, 2, and 4 showed an improvement in the Coulomb efficiency of the battery as the ratio of additives increased compared to Comparative Example 1, and the lifespan also showed a similar trend. This indicates that by adding an electrolyte containing an isocyanate compound, the dissolution effect of the aluminum negative electrode can be significantly improved, and at the same time, dendrite formation can be suppressed, extending the battery life.

[0058] Figures 6 and 7 are schematic diagrams showing the corrosion test results for Comparative Example 1 and Example 2, respectively, and the corrosion test was performed using a scanning electron microscope. As can be seen from the results in Figures 6 and 7, amine compounds are generated by the reaction of isocyanate functional groups with water in the electrolyte, and these are adsorbed onto the aluminum negative electrode surface, Al 3+ By reacting with Lewis acid, a metal complex can be formed, which in turn promotes the dissolution reaction of the aluminum anode and results in a more uniform corrosion distribution.

[0059] As described above, the present invention introduces an electrolyte containing an isocyanate compound into the design of an aluminum battery. By reacting the isocyanate functional group with water in the electrolyte, the water content in the electrolyte is reduced, suppressing the generation of harmful gases, and the aluminum dissolution reaction in the negative electrode is promoted, thereby suppressing the formation of aluminum dendrites. In this way, the service life can be effectively improved while maintaining excellent performance.

[0060] Although the present invention has been disclosed by the embodiments described above, these are not intended to limit the invention, and any person with ordinary skill in the art may make several modifications and changes without departing from the spirit and scope of the invention. Therefore, the scope of protection of the present invention shall be defined by the claims described below. [Industrial applicability]

[0061] Aluminum batteries can be applied in the field of aluminum batteries. [Explanation of symbols]

[0062] 102 Fixing member 110 Negative electrode 120 positive electrode 130 Electrolyte

Claims

1. Positive electrode and, The negative electrode and, A separator is installed between the positive electrode and the negative electrode, The separator, the positive electrode, and the negative electrode are impregnated with an electrolyte solution, An aluminum battery comprising, wherein the electrolyte comprises aluminum halide, an ionic liquid, and an additive, the additive comprising an isocyanate compound, and the isocyanate compound further comprising an acrylic acid functional group.

2. The aluminum battery according to claim 1, wherein the weight ratio of the aluminum halide, the ionic liquid, and the additive in the electrolyte is, in descending order, aluminum halide, ionic liquid, and additive.

3. The aluminum battery according to claim 1, wherein the total weight of the electrolyte is 100 wt%, and the weight ratio of the additive in the electrolyte is 0.2 wt% or more.

4. The aluminum battery according to claim 1, wherein the total weight of the electrolyte is 100 wt%, and the weight ratio of aluminum halide in the electrolyte is between 49 wt% and 65 wt%.

5. The aluminum battery according to claim 1, wherein the total weight of the electrolyte is 100 wt%, and the weight ratio of the ionic liquid in the electrolyte is between 35 wt% and 51 wt%.

6. The aluminum battery according to claim 1, wherein the total weight of the electrolyte is 100 wt%, and the sum of the weight ratios of the aluminum halide, the ionic liquid, and the additives in the electrolyte is 100 wt%.

7. The aluminum battery according to claim 1, wherein the aluminum halide contains aluminum chloride, and the ionic liquid contains 1-ethyl-3-methylimidazolium chloride.

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