WO2015030196A1

WO2015030196A1 - Electrolytic solution

Info

Publication number: WO2015030196A1
Application number: PCT/JP2014/072793
Authority: WO
Inventors: 正男三宅; 厚志遠藤; 平藤　哲司
Original assignee: 国立大学法人京都大学
Priority date: 2013-08-30
Filing date: 2014-08-29
Publication date: 2015-03-05
Also published as: JPWO2015030196A1

Abstract

Disclosed are an aluminum-plating electrolytic solution and an aluminum-secondary-battery electrolytic solution, wherein an aluminum halide is dissolved in an imidazolidinone compound represented by formula (I) (wherein R¹ and R² each independently represent a hydrogen atom, a halogen atom, a nitro group, an amino group, a carboxyl group, a hydroxyl group, a C_1-4 alkyl group that may have a substituent, a C_2-4 alkenyl group that may have a substituent, a C_1-4 alkoxy group, a C_6-12 aryl group, a C_7-13 aralkyl group, or a C_1-4 alkoxycarbonyl group), and the ratio (molar ratio) of said imidazolidinone compound/said aluminum halide is from 25/75 to 50/50. Also disclosed is a method for producing an aluminum material using said aluminum-plating electrolytic solution.

Description

Electrolyte

The present invention relates to an electrolytic solution. More specifically, the present invention relates to an electrolytic solution for aluminum plating useful as a plating solution for aluminum plating, an electrolytic solution for aluminum secondary battery useful as an electrolytic solution for an aluminum secondary battery, and production of an aluminum material using the electrolytic solution. Regarding the method.

Since the electrolytic solution for aluminum plating of the present invention can perform electrodeposition of aluminum at a temperature near room temperature, it can be used for the production of aluminum materials and the formation of an aluminum plating film on the surface of an object to be plated. Used as a liquid. The electrolytic solution for aluminum plating of the present invention is expected to be used, for example, for the manufacture of inexpensive, light and high strength structural members, electronic components, optical components and the like.

In addition, the electrolytic solution for an aluminum secondary battery of the present invention is easy to handle and can perform a charge / discharge reaction at a temperature near room temperature, for example, without being heated to a high temperature. Used as an electrolyte solution. The electrolytic solution for an aluminum secondary battery of the present invention is expected to be used, for example, in the production of secondary batteries used in portable equipment, electric vehicles and the like.

Furthermore, according to the method for producing an aluminum material of the present invention, an aluminum material can be efficiently produced at a temperature near room temperature, for example, without heating to a high temperature. It is expected to be used when developing inexpensive, lightweight, high-strength structural members, electronic / optical components, and the like.

Aluminum is expected to be used as a metal plating material in place of zinc and chromium because it has a large amount of reserves on the earth, has excellent corrosion resistance, and has a low load on humans. Since the electrodeposition potential of aluminum is significantly lower than the potential for hydrogen generation, it is difficult to deposit from an aqueous solution. Therefore, in the electrodeposition of aluminum, use of an electrolytic solution containing a non-aqueous organic solvent such as toluene as a solvent or an electrolytic solution containing a room temperature ionic liquid such as an imidazolium salt as a solvent has been studied (for example, non-patent) Reference 1). However, the electrolytic solution has many problems in terms of ease of handling and manufacturing cost.

Therefore, as a relatively inexpensive non-aqueous electrolytic solution for aluminum electrodeposition, for example, an electrolytic aluminum plating solution containing dimethyl sulfone, which is a molecular organic solvent, as a solvent has been proposed (for example, see Patent Document 1). However, since the melting point of dimethyl sulfone is 110 ° C., it is necessary to heat the plating solution to about 110 ° C. when an electrolytic aluminum plating solution containing dimethyl sulfone as a solvent is used for electrodeposition of aluminum. The electrolytic aluminum plating solution has a drawback that a great deal of energy is consumed when aluminum is electrodeposited.

JP 2006-161154 A

The present invention has been made in view of the above prior art, is easy to handle, and can be efficiently electroplated with aluminum without being heated to a high temperature. An electrolytic solution for an aluminum secondary battery that can efficiently perform a charge / discharge reaction without heating to a high temperature, and an aluminum material that can efficiently produce an aluminum material without heating to a high temperature It is an object to provide a manufacturing method.

The present invention
(1) Formula (I):

(Wherein R ¹ and R ² are each independently a hydrogen atom, a halogen atom, a nitro group, an amino group, a carboxyl group, a hydroxyl group, an optionally substituted alkyl group having 1 to 4 carbon atoms, An optionally substituted alkenyl group having 2 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 13 carbon atoms, or 1 to 4 carbon atoms Represents an alkoxycarbonyl group of
An aluminum halide is dissolved in the imidazolidinone compound represented by formula (I), and the molar ratio of the imidazolidinone compound represented by formula (I) to the aluminum halide [imidazolidinone compound / aluminum halide] is 25/75. An electrolytic solution for aluminum plating of 50/50,
(2) The object to be plated is immersed in the electrolytic solution for aluminum plating described in (1), and aluminum is electrodeposited on the surface of the object to be plated from the electrolytic solution for aluminum plating to form an aluminum plating film. And (3) Formula (I):

(Wherein R ¹ and R ² are each independently a hydrogen atom, a halogen atom, a nitro group, an amino group, a carboxyl group, a hydroxyl group, an optionally substituted alkyl group having 1 to 4 carbon atoms, An optionally substituted alkenyl group having 2 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 13 carbon atoms, or 1 to 4 carbon atoms Represents an alkoxycarbonyl group of
An aluminum halide is dissolved in the imidazolidinone compound represented by formula (I), and the molar ratio of the imidazolidinone compound represented by formula (I) to the aluminum halide [imidazolidinone compound / aluminum halide] is 25/75. The present invention relates to an electrolytic solution for an aluminum secondary battery that is ˜50 / 50.

The electrolytic solution for aluminum plating of the present invention is easy to handle and has an excellent effect of being able to efficiently deposit aluminum without being heated to a high temperature. The electrolytic solution for an aluminum secondary battery of the present invention is easy to handle, and exhibits an excellent effect that a charge / discharge reaction can be performed without heating to a high temperature. Moreover, according to the manufacturing method of the aluminum material of this invention, even if it does not heat at high temperature, the outstanding effect that an aluminum material can be manufactured efficiently is show | played.

(A) is a graph showing the results of measuring the oxidation-reduction potential of the electrolytic solution obtained in Example 1 by cyclic voltammetry, and (B) is the result after electrodeposition using the electrolytic solution obtained in Example 1. It is a drawing substitute photograph of the cathode surface. 6 is a graph showing the results of measuring the oxidation-reduction potential of the electrolytic solution obtained in Example 2 by cyclic voltammetry. (A) is a graph showing the results of measuring the oxidation-reduction potential of the electrolytic solution obtained in Example 3 by cyclic voltammetry, and (B) is the result after electrodeposition using the electrolytic solution obtained in Example 3. It is a drawing substitute photograph of the cathode surface. It is a graph which shows the result of having measured the oxidation reduction potential of the electrolyte solution obtained in Example 4 by cyclic voltammetry. It is a graph which shows the result of having measured the oxidation reduction potential of the electrolyte solution obtained in Example 5 by cyclic voltammetry. 6 is a graph showing the results of measuring the oxidation-reduction potential of the electrolytic solution obtained in Comparative Example 1 by cyclic voltammetry. (A) is the graph which shows the result which adjusted the temperature of the electrolyte solution obtained in Example 3 to 25 degreeC, and measured the oxidation-reduction potential of the said electrolyte solution by cyclic voltammetry, (B) is obtained in Example 3. It is the drawing substitute photograph of the cathode surface after adjusting the temperature of the obtained electrolyte solution to 25 degreeC, and electrodepositing using the said electrolyte solution. It is a graph which shows the result of having adjusted the temperature of the electrolyte solution obtained in Example 4 to 25 degreeC, and measuring the oxidation reduction potential of the said electrolyte solution by cyclic voltammetry. It is a drawing substitute photograph of the cathode surface after adjusting the temperature of the electrolyte solution obtained in Example 3 to 40 degreeC, and electrodepositing using the said electrolyte solution. It is a drawing substitute photograph of the cathode surface after adjusting the temperature of the electrolyte solution obtained in Example 3 to 50 degreeC, and electrodepositing using the said electrolyte solution. (A) is a drawing-substituting photograph of the cathode surface after electrodepositing at a current density of 0.25 mA / cm ² using the electrolytic solution obtained in Example 3, and (B) is an electrolysis obtained in Example 3. FIG. 5 is a drawing-substituting photograph of the cathode surface after electrodeposition at a current density of 0.5 mA / cm ² using a liquid. (A) is a drawing-substituting photograph of the cathode surface after electrodepositing at a current density of 0.75 mA / cm ² using the electrolytic solution obtained in Example 6, and (B) is an electrolysis obtained in Example 7. (C) is a substitute for a drawing of the cathode surface when electrodeposited at a current density of 0.5 mA / cm ² , and the electrolyte obtained in Example 7 is used at a current density of 1 mA / cm ^2. (D) is a drawing substitute photograph of the cathode surface after electrodeposition using the electrolytic solution obtained in Example 3 at a current density of 0.5 mA / cm ^2. is there. (A) is a drawing-substituting photograph of the surface of the aluminum plating film obtained in Experiment No. 12, (B) is a drawing-substituting photograph of the surface of the aluminum plating film obtained in Experiment No. 15, and (C) is before the electrodeposition. It is a drawing substitute photograph of the cathode surface. 6 is an X-ray diffraction pattern of an aluminum plating film obtained in Experiment No. 15. FIG. 6 is a drawing-substituting photograph of the cathode surface after electrodeposition using the electrolytic solution obtained in Example 8. FIG. (A) is a graph showing the results of cyclic voltammetry measurement of the oxidation-reduction potential of the electrolytic solution obtained in Example 9, and (B) is the result after electrodeposition using the electrolytic solution obtained in Example 9. It is a drawing substitute photograph of the cathode surface. 6 is a drawing-substituting photograph of the cathode surface after electrodeposition using the electrolytic solution obtained in Example 10. FIG. In Experiment 8, it is a graph which shows the result of having adjusted the temperature of the electrolyte solution obtained in Example 2 and Comparative Example 2 to 80 degreeC, and measuring the oxidation-reduction potential of the said electrolyte solution by cyclic voltammetry.

(Electrolytic solution for aluminum plating and electrolytic solution for aluminum secondary battery)
In one aspect, the present invention provides formula (I):

(Wherein R ¹ and R ² are each independently a hydrogen atom, a halogen atom, a nitro group, an amino group, a carboxyl group, a hydroxyl group, an optionally substituted alkyl group having 1 to 4 carbon atoms, An optionally substituted alkenyl group having 2 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 13 carbon atoms, or 1 to 4 carbon atoms Represents an alkoxycarbonyl group of
An aluminum halide is dissolved in the imidazolidinone compound represented by formula (I), and the molar ratio of the imidazolidinone compound represented by formula (I) to the aluminum halide [imidazolidinone compound / aluminum halide] is 25/75. It is an electrolytic solution for aluminum plating of ˜50 / 50. In another aspect of the present invention, an aluminum halide is dissolved in the imidazolidinone compound represented by the formula (I), and the mole of the imidazolidinone compound represented by the formula (I) and the aluminum halide is An electrolytic solution for an aluminum secondary battery having a ratio [imidazolidinone compound / aluminum halide] of 25/75 to 50/50. Hereinafter, unless otherwise specified, the electrolytic solution for aluminum plating and the electrolytic solution for aluminum secondary battery are referred to as “electrolytic solution”.

In the electrolytic solution of the present invention, an aluminum halide is dissolved in an imidazolidinone compound represented by the formula (I) [hereinafter simply referred to as an imidazolidinone compound], and an imidazolidinone compound / aluminum halide (molar ratio). Is 25/75 to 50/50, for example, aluminum can be deposited (reduction of aluminum ions) and dissolved (aluminum oxidation) even at a temperature near room temperature without being heated to a high temperature. Accordingly, by using the electrolytic solution of the present invention, for example, electrodeposition of aluminum and charge / discharge reaction (oxidation-reduction reaction) can be performed even at a temperature near room temperature without heating to a high temperature.

The imidazolidinone compound is used as a solvent for dissolving the aluminum halide. The imidazolidinone compound has a higher flash point and lower volatility than toluene, which is used as a solvent for the conventional electrolytic solution for aluminum electrodeposition, in the temperature range where the electrolytic solution is normally used. Is easy.

In the formula (I), R ¹ and R ² each independently represent a hydrogen atom, a halogen atom, a nitro group, an amino group, a carboxyl group, a hydroxyl group, or an alkyl having 1 to 4 carbon atoms which may have a substituent. An optionally substituted alkenyl group having 2 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 13 carbon atoms, or 1 carbon atom 4 to 4 alkoxycarbonyl groups.

In R ¹ and R ² , examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. However, the present invention is not limited to such examples.

In R ¹ and R ² , the optionally substituted alkyl group having 1 to 4 carbon atoms has 1 or more carbon atoms, and from the viewpoint of improving the ease of handling of the electrolytic solution, 4 or less, Preferably it is 2 or less. Examples of the alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, and a tert-butyl group. It is not limited to illustration only. Examples of the substituent include a halogen atom and a hydroxyl group, but the present invention is not limited to such examples.

In R ¹ and R ² , the carbon number of the alkenyl group having 1 to 4 carbon atoms which may have a substituent is 2 or more, and from the viewpoint of improving the ease of handling of the electrolytic solution, 4 or less, Preferably it is 3 or less. Examples of the alkenyl group having 2 to 4 carbon atoms include a vinyl group, an isopropenyl group, an allyl group, and a butenyl group, but the present invention is not limited to such examples. The substituent in the alkenyl group having 1 to 4 carbon atoms which may have a substituent is the same as the substituent in the alkyl group having 1 to 4 carbon atoms which may have a substituent.

In R ¹ and R ² , the alkoxy group has 1 or more carbon atoms, and is 4 or less, preferably 3 or less, from the viewpoint of improving the ease of handling of the electrolytic solution. Examples of the alkoxy group having 2 to 4 carbon atoms include a methoxy group, an ethoxy group, a propoxy group, a butoxy group, and the like, but the present invention is not limited to such examples.

In R ¹ and R ² , the aryl group has 6 or more carbon atoms, and is 12 or less, preferably 8 or less, more preferably 7 or less, from the viewpoint of improving the ease of handling of the electrolytic solution. Examples of the aryl group having 6 to 8 carbon atoms include a phenyl group and a tolyl group, but the present invention is not limited to such examples.

In R ¹ and R ² , the aralkyl group has 7 or more carbon atoms, and is 13 or less, preferably 10 or less, more preferably 9 or less, from the viewpoint of improving the ease of handling of the electrolytic solution. Examples of the aralkyl group having 7 to 13 carbon atoms include a phenylmethyl group, a 2-phenylethyl group, a 3-phenylpropyl group, and a 4-phenylbutyl group. However, the present invention is limited to such examples. It is not something.

In R ¹ and R ² , the alkoxy group of the alkoxycarbonyl group has 1 or more carbon atoms, and is 4 or less, preferably 3 or less from the viewpoint of improving the ease of handling of the electrolytic solution. Examples of the alkoxycarbonyl group having 1 to 4 carbon atoms include a methoxycarbonyl group, an ethoxycarbonyl group, and a propoxycarbonyl group. However, the present invention is not limited to such examples.

Among these functional groups used for R ¹ and R ² , an alkyl group having 1 to 4 carbon atoms is preferable, a methyl group and an ethyl group are more preferable, and methyl More preferred are groups.

Examples of the imidazolidinone compound include 1,3-dimethyl-2-imidazolidinone, 1-methyl-3-ethyl-2-imidazolidinone, 1,3-diethyl-2-imidazolidinone, 1,3 Dialkylimidazolidinone compounds such as di (n-propyl) -2-imidazolidinone and 1,3-di (n-butyl) -2-imidazolidinone, 1,3-divinyl-2-imidazolidinone, etc. 1,3-dialkenylimidazolidinone compounds; 1-methyl-3-phenyl-2-imidazolidinone, 1-methyl-3-phenyl-4-imidazolidinone, 3-methyl-1-phenyl-4- Alkyl aryl imidazolidinone compounds such as imidazolidinone; 1,3-diphenyl-2-imidazolidinone, 1,3-diphenyl-4-imidazolidinone, etc. Although such diaryl imidazolidinone compounds, the present invention is not limited only to those exemplified. Among these imidazolidinone compounds, since both the efficiency of electrodeposition of aluminum and charge / discharge reaction and economy are satisfied, dialkylimidazolidinone compounds are preferred, and 1,3-dimethyl-2 is more preferred. -Imidazolidinone.

Examples of the aluminum halide include aluminum fluoride, aluminum chloride, aluminum bromide, aluminum iodide, and the like, but the present invention is not limited to such examples. Among these, aluminum chloride and aluminum bromide are preferable from the viewpoint of efficiently performing aluminum electrodeposition and charge / discharge reaction, and satisfy both the efficiency and economic efficiency of aluminum electrodeposition and charge / discharge reaction. Aluminum chloride is more preferred.

The molar ratio of the imidazolidinone compound and the aluminum halide (imidazolidinone compound / aluminum halide) is 25/75 or more, preferably 33/67 or more, from the viewpoint of sufficiently ensuring the ease of handling of the electrolytic solution. More preferably, it is 38/62 or more, and it is 50/50 or less, preferably 49/51 or less, more preferably 46/54 or less, from the viewpoint of efficiently performing aluminum electrodeposition and charge / discharge reaction.

When the electrolytic solution of the present invention is used for production of an aluminum material, that is, when the electrolytic solution of the present invention is an electrolytic solution for aluminum plating, from the viewpoint of improving the smoothness of the aluminum plating film, for example, tetraethylammonium chloride, It is preferable to include an organic solvent such as ethylenetetramine, benzene, toluene, xylene in the electrolytic solution of the present invention.

When the electrolytic solution of the present invention is an electrolytic solution for aluminum plating, the amount of the organic solvent in the electrolytic solution of the present invention varies depending on the type of the organic solvent, the use of the electrolytic solution, etc., and thus cannot be determined unconditionally. For this reason, it is preferable to determine appropriately depending on the type of the organic solvent, the use of the electrolyte, and the like. For example, when triethylenetetramine is used as the organic solvent in the electrolytic solution of the present invention when producing an aluminum material having a smooth surface aluminum plating film, the total amount of imidazolidinone compound and aluminum halide is 100 mol. The amount of per organic solvent is usually preferably 0.1 to 2 mol, more preferably 0.5 to 1.5 mol. In addition, in the case of using benzene, toluene or xylene as the organic solvent in the electrolytic solution of the present invention when producing an aluminum material having a smooth surface aluminum plating film, the total amount of imidazolidinone compound and aluminum halide The amount of the organic solvent per 100 moles is preferably 0.1 to 150 moles, more preferably 50 to 120 moles.

As described above, the electrolytic solution for aluminum plating of the present invention is easy to handle. Moreover, according to the electrolytic solution for aluminum plating of the present invention, aluminum can be deposited and dissolved efficiently even at a temperature near room temperature, for example, without heating to a high temperature. Therefore, according to the electrolytic solution for aluminum plating of the present invention, it is possible to efficiently deposit aluminum, for example, even at a temperature near room temperature, without heating to a high temperature. As described above, according to the electrolytic solution for aluminum plating of the present invention, aluminum can be efficiently electrodeposited even at a temperature near room temperature without being heated to a high temperature. It is expected to be used for forming an aluminum plating film on the surface of a plated object.

Moreover, the electrolytic solution for an aluminum secondary battery of the present invention is easy to handle. Further, according to the electrolytic solution of the present invention, it is possible to efficiently reduce aluminum ions and oxidize aluminum even at a temperature near room temperature, for example, without heating to a high temperature. Therefore, according to the electrolytic solution of the present invention, the charge / discharge reaction (oxidation-reduction reaction) can be performed efficiently even at a temperature near room temperature, for example, without heating to a high temperature. As described above, according to the electrolytic solution of the present invention, the charge / discharge reaction can be performed efficiently even at a temperature near room temperature, for example, without being heated to a high temperature. It is expected to be used for the production of secondary batteries and the like.

(Method for producing aluminum material)
The method for producing an aluminum material of the present invention is a method for producing an aluminum material in which an aluminum plating film is formed on the surface of an object to be plated, and the object to be plated is immersed in the electrolytic solution for aluminum plating. Aluminum is deposited on the surface of the object to be plated from the electrolytic solution for forming an aluminum plating film.

In the method for producing an aluminum material of the present invention, the operation of electrodepositing aluminum using the electrolytic solution for aluminum plating is employed. Therefore, even if it is not heated to a high temperature, for example, it is efficient even at a temperature near room temperature. An aluminum plating film can be formed on the surface of the object to be plated. Therefore, according to the method for producing an aluminum material of the present invention, an aluminum material can be produced efficiently even at a temperature near room temperature, for example, without heating to a high temperature.

Aluminum material is a material in which an aluminum plating film is formed on the surface of an object to be plated. Examples of the material constituting the object to be plated include metals other than aluminum, conductive materials such as alloys, non-conductive materials such as plastics, etc., but the present invention is limited only to such examples. It is not a thing. When a non-conductive material such as plastic is used as the material of the object to be plated, the non-conductive material is pre-conductive by performing electroless plating on the object to be plated made of the non-conductive material, for example. It can be used with imparting properties.

Aluminum electrodeposition is performed in an inert gas atmosphere. Examples of the inert gas include argon gas and nitrogen gas, but the present invention is not limited to such examples.

When aluminum is electrodeposited, an electrolytic cell is used. The size and shape of the electrolytic cell may be any suitable size and shape of the intended aluminum material, and the present invention is related to this. It is not limited by the size and shape of the electrolytic cell.

For the electrodeposition of aluminum, for example, the electrolytic solution for aluminum plating is placed in an electrolytic cell, an anode and a cathode are inserted into the electrolytic solution for aluminum plating in the electrolytic cell, and electricity is passed between the anode and the cathode. Can be done. By performing this operation, aluminum can be electrodeposited from the electrolytic solution for aluminum plating.

Examples of the anode include an electrode made of aluminum and an electrode made of a base material having a surface layer made of aluminum. However, the present invention is not limited to such examples. Examples of the material constituting the substrate include a conductive metal other than aluminum, a conductive material such as a conductive alloy, and a nonconductive material such as a nonconductive plastic. It is not limited only to such illustration. An object to be plated can be used for the cathode.

Since the amount of electricity applied when electrodepositing aluminum varies depending on the intended use of the aluminum material and the thickness required for the aluminum plating film, etc., it cannot be determined unconditionally, so the intended use of the aluminum material, It is preferable to determine appropriately according to the thickness required for the aluminum plating film.

The current density when energizing between the anode and the cathode inserted into the aluminum plating electrolyte is the temperature of the aluminum plating electrolyte when performing electrodeposition (hereinafter referred to as electrodeposition temperature), It depends on the type of imidazolidinone compound, the type of aluminum halide used in the electrolytic solution for aluminum plating, and the molar ratio of the imidazolidinone compound and aluminum halide in the electrolytic solution for aluminum plating. The electrodeposition temperature, the type of imidazolidinone compound, the type of aluminum halide used in the electrolytic solution for aluminum plating, the imidazolidinone compound and the aluminum halide in the electrolytic solution for aluminum plating, and Depending on the molar ratio of It is preferable to determine Yibin.

The electrodeposition temperature is the current density, the type of imidazolidinone compound, the type of aluminum halide used in the electrolytic solution for aluminum plating, and the molar ratio of the imidazolidinone compound and aluminum halide in the electrolytic solution for aluminum plating. Since it cannot be determined in general, it depends on the current density, type of imidazolidinone compound, type of aluminum halide used in the electrolytic solution for aluminum plating, and imidazolidin in the electrolytic solution for aluminum plating. It is preferable to determine appropriately according to the molar ratio between the non-compound and the aluminum halide. The electrodeposition temperature is usually from room temperature (25 ° C.) to 100 ° C. As described above, according to the method for producing an aluminum material of the present invention, aluminum can be electrodeposited from the electrolytic solution for aluminum plating at a relatively low temperature. Aluminum materials can be produced even at temperatures.

Since the time required for electrodeposition of aluminum varies depending on the current density, electrodeposition temperature, amount of energization, etc., it cannot be determined unconditionally, so it should be determined appropriately according to the current density, electrodeposition temperature, amount of energization, etc. Is preferred.

As described above, according to the method for producing an aluminum material of the present invention, an aluminum material can be produced efficiently even at a temperature near room temperature, for example, without heating to a high temperature. Therefore, the electrolytic solution of the present invention and the method for producing the aluminum material of the present invention are expected to be used, for example, in the development of an inexpensive, lightweight and high-strength structural member.

Next, the present invention will be described in more detail based on examples. However, the present invention is not limited to such examples.

Example 1
In a glove box maintained in an argon gas atmosphere, an imidazolidinone compound (1,3-dimethyl-2-imidazolidinone) in which R ¹ and R ² are both methyl groups in formula (I) and aluminum halogen Compound (aluminum chloride) was mixed with 1,3-dimethyl-2-imidazolidinone / aluminum chloride (molar ratio) to be 48.8 / 51.2 to obtain an electrolytic solution.

Example 2
Example 1 and Example 1, except that 1,3-dimethyl-2-imidazolidinone / aluminum chloride (molar ratio) was changed from 48.8 / 51.2 to 45.5 / 54.5. Similarly, an electrolytic solution was obtained.

Example 3
Example 1 and Example 1, except that 1,3-dimethyl-2-imidazolidinone / aluminum chloride (molar ratio) was changed from 48.8 / 51.2 to 40.0 / 60.0. Similarly, an electrolytic solution was obtained.

Example 4
Example 1 and Example 1, except that 1,3-dimethyl-2-imidazolidinone / aluminum chloride (molar ratio) was changed from 48.8 / 51.2 to 38.5 / 61.5. Similarly, an electrolytic solution was obtained.

Example 5
Example 1 and Example 1, except that 1,3-dimethyl-2-imidazolidinone / aluminum chloride (molar ratio) was changed from 48.8 / 51.2 to 33.3 / 66.7. Similarly, an electrolytic solution was obtained.

Comparative Example 1
In Example 1, except that 1,3-dimethyl-2-imidazolidinone / aluminum chloride (molar ratio) was changed from 48.8 / 51.2 to 76.9 / 23.1, Similarly, an electrolytic solution was obtained.

Production Example 1
In a glove box maintained in an argon gas atmosphere, a glassy carbon electrode (diameter: 3.0 mm, length: 55 mm) is polished with diamond paste, washed with distilled water and ethanol, and then cooled with cold air. A working electrode was obtained by drying.

Production Example 2
An aluminum plate (purity: 99% by mass, width: 20 mm, length: 30 mm, thickness: 1.0 mm) and silicon carbide polishing paper (P # 220) in a glove box maintained in an argon gas atmosphere Then, after washing with distilled water and ethanol, it was dried with cold air to obtain a counter electrode.

Production Example 3
In a glove box maintained in an argon gas atmosphere, an aluminum wire (purity: 99 mass%, diameter: 0.80 mm, length: 100 mm) is polished with a silicon carbide polishing paper (P # 220), After washing with distilled water and ethanol, drying with cold air yielded a reference electrode.

Production Example 4
In a glove box maintained in an argon gas atmosphere, a copper plate material (purity: 99.99 mass%, width: 15 mm, length: 30 mm, thickness: 0.5 mm) was placed on a silicon carbide abrasive paper (P # 1200). No.), washed with distilled water and ethanol, and then dried with cold air. Next, the surface of the copper plate material was covered with a polytetrafluoroethylene tape so that the exposed portion of the copper plate material after drying was 1 cm ² to obtain a cathode.

Production Example 5
In a glove box maintained in an argon gas atmosphere, an aluminum plate (purity: 99% by mass, width: 20 mm, length: 30 mm, thickness: 1.0 mm) is polished with silicon carbide abrasive paper (P # 220). ), Washed with distilled water and ethanol, and then dried with cold air to obtain an anode.

Test example 1
(1) Cyclic voltammetry In a glove box kept in an argon gas atmosphere, the working electrode obtained in Production Example 1, the counter electrode obtained in Production Example 2, the reference electrode obtained in Production Example 3, Using the electrolytic solution obtained in Example 1, a three-electrode electrochemical cell (Experiment No. 1) was produced.

In the above, instead of the electrolytic solution obtained in Example 1, the electrolytic solution obtained in Example 2 (Experiment No. 2), the electrolytic solution obtained in Example 3 (Experiment No. 3), and in Example 4 The same as above except that the obtained electrolytic solution (Experiment No. 4), the electrolytic solution obtained in Example 5 (Experiment No. 5) and the electrolytic solution obtained in Comparative Example 1 (Experiment No. 6) were used. By performing the above operations, a three-electrode electrochemical cell was produced.

Using the three-electrode electrochemical cell obtained in Experiment Nos. 1 to 6 and the electrochemical measurement system [Hokuto Denko Co., Ltd., product number: HZ-5000], cyclic voltammetry measurement under the conditions shown in Table 1 Was done. In the table, “DMI” represents 1,3-dimethyl-2-imidazolidinone, and “AlCl ₃ ” represents aluminum chloride.

In addition, the temperature of the electrolyte solution in the

experiment numbers

3, 5, and 6 is different from the temperature of the electrolyte solution in the

experiment numbers

1, 2, and 4. However, in cyclic voltammetry, the temperature of the electrolyte does not affect the appearance of current peaks caused by aluminum dissolution and precipitation, respectively. It is considered that the difference in the temperature of the electrolyte solution in Experiment Nos. 1 to 6 does not affect the presence or absence of aluminum dissolution and precipitation.

In Test Example 1, the results of measuring the redox potential of the electrolytic solution obtained in Example 1 by cyclic voltammetry are shown in FIG. 1 (A), and the redox potential of the electrolytic solution obtained in Example 2 is cyclic. FIG. 2 shows the results measured by voltammetry, FIG. 3 (A) shows the results of the cyclic reduction of the redox potential of the electrolyte obtained in Example 3, and FIG. 3A shows the oxidation of the electrolyte obtained in Example 4. FIG. 4 shows the result of measuring the reduction potential by cyclic voltammetry, FIG. 5 shows the result of measuring the oxidation-reduction potential of the electrolytic solution obtained in Example 5, and FIG. 5 shows the electrolytic solution obtained in Comparative Example 1. The result of measuring the oxidation-reduction potential of the product by cyclic voltammetry is shown in FIG.

From the results shown in FIGS. 1 to 5, when the potential is swept from the natural potential (about 0.3 V) to the cathode side, the cathode current rises around the potential of 0 V (see arrow A in FIGS. 1 to 5). As can be seen, aluminum ions in the electrolytic solution are reduced and aluminum is deposited.

On the other hand, from the results shown in FIGS. 1 to 5, when the sweep is turned back at a potential of −4 V or −1 V and the potential is swept to the anode side, the anode current starts from around 0 V (see arrow B in FIGS. 1 to 5). It can be seen that the rise of is seen. In Test Example 1, since a reference electrode made of an aluminum wire is used as a reference electrode of a three-electrode electrochemical cell, when aluminum is present on the surface of the working electrode, the oxidation of aluminum is performed at a potential of 0 V or more. It is expected that an electric current will be generated due to dissolution by. Therefore, it can be seen from the results shown in FIGS. 1 to 5 that the precipitated aluminum is dissolved.

From the above results, 1,3-dimethyl-2-imidazolidinone / aluminum chloride (molar ratio) was 48.8 / 51.2 (Example 1), 45.5 / 54.5 (Example 2), In the case of using electrolytic solutions of 40.0 / 60.0 (Example 3), 38.5 / 61.5 (Example 4) and 33.3 / 66.7 (Example 5), aluminum was used. Since it is possible to perform ion reduction and aluminum oxidation, it can be seen that aluminum electrodeposition and charge / discharge reactions can be performed.

On the other hand, from the result shown in FIG. 6, when the potential is swept from the natural potential (about 0.3 V) to the cathode side, the rise of the cathode current is observed around the potential of 0 V (see arrow A in FIG. 6). This indicates that no aluminum is deposited. Further, from the results shown in FIG. 6, when the sweep is turned back at a potential of −4V or −1V and the potential is swept to the anode side, the rise of the anode current near the potential of 0V (see arrow B in FIG. 6). From this, it can be seen that there is no aluminum on the working electrode. From these results, reduction of aluminum ions and oxidation of aluminum can be performed even with an electrolyte solution having a 1,3-dimethyl-2-imidazolidinone / aluminum chloride (molar ratio) of 76.9 / 23.1. I can't understand.

From the above results, the use of an electrolytic solution containing an imidazolidinone compound and an aluminum halide and having an imidazolidinone compound / aluminum halide (molar ratio) of 25/75 to 50/50 can be used. It can be seen that deposition and charge / discharge reactions can be performed.

(2) Electrodeposition of aluminum The electrolytic solution (experiment number 7) obtained in Example 1 was put in an electrolytic cell. Thereafter, the cathode obtained in Production Example 4, the anode obtained in Production Example 5 and the reference electrode obtained in Production Example 3 were inserted into the electrolytic solution in the electrolytic cell, and the anode was subjected to the conditions shown in Table 2. Electrodeposition was carried out by energizing between the cathode and the cathode. At this time, it was confirmed that the current between the anode and the cathode was 4.3 mA / cm ² .

The electrolytic solution (experiment number 8) obtained in Example 3 was placed in an electrolytic cell. Thereafter, the cathode obtained in Production Example 4 and the anode obtained in Production Example 5 were inserted into the electrolytic solution in the electrolytic cell, and electricity was passed between the anode and the cathode under the conditions shown in Table 2. Electrodeposited.

In Test Example 1, an optical photograph of the cathode surface after electrodeposition using the electrolytic solution obtained in Example 1 was electrodeposited using the electrolytic solution obtained in FIG. An optical photograph of the cathode surface is shown in FIG. In the figure, the scale bar indicates 10 mm.

From the results shown in FIG. 1 (B) and FIG. 3 (B), when electrodeposition was performed using the electrolytic solution obtained in Example 1 and the electrolytic solution obtained in Example 3, the surface of the cathode was plated with aluminum. It can be seen that a film is formed. In addition, when using the electrolytic solution obtained in Example 2, the electrolytic solution obtained in Example 4, and the electrolytic solution obtained in Example 5, as described above, the reduction of aluminum ions and the aluminum Since oxidation can be performed, it is considered that an aluminum plating film is formed in the same manner as when electrodeposition is performed using the electrolytic solution obtained in Example 1 and the electrolytic solution obtained in Example 3.

Based on the above results, it was found that an electrolytic solution containing an imidazolidinone compound and an aluminum halide and having an imidazolidinone compound / aluminum halide (molar ratio) of 25/75 to 50/50 can be used to charge aluminum. It can be seen that it can be analyzed. The imidazolidinone compound has a high flash point and low volatility in the temperature range in which the electrolytic solution is usually used, as compared with toluene used as a solvent for an electrolytic solution for conventional aluminum electrodeposition. Since the handling is easy, the electrolytic solution is easy to handle. In addition, since the imidazolidinone compound has a lower melting point than dimethylsulfone used as a solvent for a conventional electrolytic solution for aluminum electrodeposition, the electrolytic solution is a conventional electrolytic solution containing dimethylsulfone. It is considered that aluminum can be electrodeposited at a lower temperature range.

Test example 2
(1) Cyclic voltammetry In a glove box kept in an argon gas atmosphere, the working electrode obtained in Production Example 1, the counter electrode obtained in Production Example 2, the reference electrode obtained in Production Example 3, A three-electrode electrochemical cell was prepared using the electrolytic solution obtained in Example 3 (Experiment No. 9) or the electrolytic solution obtained in Example 4 (Experiment No. 10).

Using the three-electrode electrochemical cell obtained above and an electrochemical measurement system (Hokuto Denko Co., Ltd., product number: HZ-5000), the temperature of the electrolyte solution: 25 ° C., sweep rate: 10 mV / s, Sweep range: Cyclic voltammetry was performed under the condition of −1 to 2 V with respect to aluminum.

In Test Example 2, the temperature of the electrolytic solution obtained in Example 3 was adjusted to 25 ° C., and the result of measuring the oxidation-reduction potential of the electrolytic solution by cyclic voltammetry was obtained in FIG. FIG. 8 shows the results of adjusting the temperature of the obtained electrolyte to 25 ° C. and measuring the oxidation-reduction potential of the electrolyte by cyclic voltammetry.

From the results shown in FIG. 7 (A), when using the electrolytic solution obtained in Example 3 and adjusting the temperature of the electrolytic solution to 25 ° C., using the electrolytic solution obtained in Example 3, When the temperature of the electrolyte is adjusted to 80 ° C. (see FIG. 3A), when the potential is swept from the natural potential (about 0.3 V) to the cathode side, the potential is around 0 V [FIG. ), The rising edge of the cathode current is observed, indicating that aluminum ions in the electrolytic solution are reduced and aluminum is deposited.

Further, from the result shown in FIG. 7A, when the electrolytic solution obtained in Example 3 was used and the temperature of the electrolytic solution was adjusted to 25 ° C., the electrolytic solution obtained in Example 3 was used. When the temperature of the electrolyte is adjusted to 80 ° C. (see FIG. 3A), the sweep is turned back at a potential of −1 V or less, and when the potential is swept to the anode side, the potential is around 0 V [see FIG. 7 (A), see arrow B], the rising of the anode current is seen, indicating that the precipitated aluminum is dissolved.

On the other hand, from the results shown in FIG. 8, when the electrolytic solution obtained in Example 4 was used and the temperature of the electrolytic solution was adjusted to 25 ° C., the electrolytic solution obtained in Example 4 was used, and the electrolytic solution Similar to when the temperature of the liquid was adjusted to 60 ° C. (see FIG. 4), when the potential was swept from the natural potential (about 0.3 V) to the cathode side, the potential was around 0 V (see arrow A in FIG. 8). The rise of the cathode current can be seen in FIG. 3, indicating that aluminum ions in the electrolytic solution are reduced and aluminum is deposited.

Further, from the results shown in FIG. 8, when the electrolytic solution obtained in Example 4 was used and the temperature of the electrolytic solution was adjusted to 25 ° C., the electrolytic solution obtained in Example 4 was used, and the electrolytic solution Similar to when the temperature of the liquid was adjusted to 60 ° C. (see FIG. 4), the sweep was turned back at a potential of −1 V or less, and when the potential was swept to the anode side, the potential was around 0 V (see arrow B in FIG. 8). ) Shows that the anode current rises, indicating that the precipitated aluminum is dissolved.

From these results, an electrolyte solution containing an imidazolidinone compound and an aluminum halide and having an imidazolidinone compound / aluminum halide (molar ratio) of 25/75 to 50/50 was used. It can be seen that aluminum can be electrodeposited when the temperature is adjusted to 25 ° C.

(2) Electrodeposition of aluminum After the electrolytic solution obtained in Example 3 was put in the electrolytic cell, the cathode obtained in Production Example 4 and the obtained in Production Example 5 in the electrolytic solution in the electrolytic cell Electrodeposition was performed by inserting an anode and applying current between the anode and the cathode under the conditions shown in Table 3.

In Test Example 2, the temperature of the electrolytic solution obtained in Example 3 was adjusted to 25 ° C., and an optical photograph of the cathode surface after electrodeposition using the electrolytic solution is shown in FIG. The temperature of the electrolyte solution obtained was adjusted to 40 ° C., and an optical photograph of the cathode surface after electrodeposition using the electrolyte solution was adjusted to 50 ° C. in FIG. 9 and the electrolyte solution obtained in Example 3 FIG. 10 shows an optical photograph of the cathode surface after electrodeposition using the electrolytic solution. In the figure, the scale bar indicates 10 mm. Moreover, the state of the cathode surface was evaluated based on the following evaluation criteria. The results are shown in Table 3.

<Evaluation criteria>
AA: An aluminum plating film having a silvery white surface and a smooth surface is formed on the cathode surface.
A: An aluminum plating film is formed on the cathode surface.

From the results shown in FIG. 7B, FIG. 9 and FIG. 10, when the temperature of the electrolyte was adjusted to 25 ° C. (experiment number 11), 40 ° C. (experiment number 12) and 50 ° C. (experiment number 13). It can be seen that aluminum can be electrodeposited. In particular, from the results shown in Table 3, when the electrolyte temperature was adjusted to 40 ° C. (experiment number 12) and 50 ° C. (experiment number 13), a silver-white aluminum plating film (in the figure, It can be seen that an arrow is formed.

From these results and the results shown in FIGS. 1 to 5, it contains an imidazolidinone compound and an aluminum halide, and the imidazolidinone compound / aluminum halide (molar ratio) is 25/75 to 50/50. It can be seen that when the electrolytic solution is used and the temperature of the electrolytic solution is adjusted to 25 to 80 ° C., aluminum can be electrodeposited well. Therefore, according to the said electrolyte solution, since aluminum can be electrodeposited favorable also at the temperature of normal temperature, it turns out that manufacture of an aluminum material and an aluminum plating film can be formed efficiently.

(3) Elemental analysis of aluminum plating film Obtained by Experiment No. 12 using an energy dispersive X-ray analyzer (manufactured by Oxford Instruments, trade name: INCAxact) attached to a scanning electron microscope Elemental analysis of the aluminum plating film was performed. As a result, it was confirmed that the plating film was composed of 99.71 atomic% aluminum and 0.29 atomic% chlorine.

The results shown in FIGS. 1 to 5 indicate that aluminum can be electrodeposited when the temperature of the electrolyte is adjusted to 60 to 80 ° C.

Based on the above results, an electrolytic solution containing an imidazolidinone compound and an aluminum halide and having an imidazolidinone compound / aluminum halide (molar ratio) of 25/75 to 50/50 was used. It can be seen that aluminum can be electrodeposited when the temperature is adjusted to 25-80 ° C.

Test example 3
After putting the electrolytic solution obtained in Example 3 into the electrolytic cell, the cathode obtained in Production Example 4 and the anode obtained in Production Example 5 were inserted into the electrolytic solution in the electrolytic cell, Electrodeposition was performed by applying current between the anode and the cathode under the conditions shown in Table 4 (experiment numbers 14 and 12).

In Test Example 3, using the electrolytic solution obtained in Example 3, an optical photograph of the cathode surface after electrodeposition (experiment number 14) at a current density of 0.25 mA / cm ² is shown in FIG. FIG. 11B shows an optical photograph of the cathode surface after electrodeposition (Experiment No. 12) using the electrolytic solution obtained in Example 3 at a current density of 0.5 mA / cm ² . In the figure, the scale bar indicates 10 mm. Moreover, the state of the cathode surface was evaluated based on the following evaluation criteria. The results are shown in Table 4.

<Evaluation criteria>
AA: An aluminum plating film having a silvery white surface and a smooth surface is formed on the cathode surface.
A: An aluminum plating film having a silver white color is formed on the cathode surface.

From the results shown in FIG. 11 and Table 4, when the current density was adjusted to 0.25 mA / cm ² (experiment number 14) and 0.5 mA / cm ² (experiment number 12), an aluminum plating film ( It can be seen that (see the arrow in the figure) is formed. In particular, from the results shown in Table 4, when the current density was adjusted to 0.5 mA / cm ² (Experiment No. 12), an aluminum plating film having a silver white color on the cathode surface and a smooth surface (see FIG. It can be seen that an arrow) is formed.

Example 6
In a glove box kept in an argon gas atmosphere, an imidazolidinone compound (1,3-dimethyl-2-imidazolidinone) in which R ¹ and R ² are methyl groups in formula (I) and an aluminum halide ( Aluminum chloride) and an additive (tetraethylammonium chloride) are mixed so that 1,3-dimethyl-2-imidazolidinone / aluminum chloride / tetraethylammonium chloride (molar ratio) is 40/60/1. A liquid was obtained.

Example 7
Example 6 is the same as Example 6 except that 1,3-dimethyl-2-imidazolidinone / aluminum chloride / tetraethylammonium chloride (molar ratio) was changed from 40/60/1 to 40/60/2 in Example 6. The electrolyte solution was obtained by performing the same operation.

Test example 4
(1) Electrodeposition of aluminum The electrolytic solution obtained in Example 6 (Experiment No. 15), the electrolytic solution obtained in Example 7 (Experiment No. 16 and Experimental No. 17), or the electrolytic solution obtained in Example 3 (Experiment No. 12) was placed in the electrolytic cell, and then the cathode obtained in Production Example 4 and the anode obtained in Production Example 5 were inserted into the electrolytic solution in the electrolytic cell. Electrodeposition was performed by applying current between the anode and the cathode under conditions.

In Test Example 4, using the electrolytic solution obtained in Example 6, an optical photograph of the cathode surface after electrodeposition (experiment number 15) at a current density of 0.75 mA / cm ² is shown in FIG. Using the electrolytic solution obtained in Example 7, an optical photograph of the cathode surface after electrodeposition (experiment number 16) at a current density of 0.5 mA / cm ² was obtained in FIG. Using the electrolytic solution, an optical photograph of the cathode surface after electrodeposition (experiment number 17) at a current density of 1 mA / cm ² is 0.5 mA using the electrolytic solution obtained in FIG. 12 (C) and Example 3. An optical photograph of the cathode surface after electrodeposition (experiment number 12) at a current density of / cm ² is shown in FIG. In the figure, the scale bar indicates 10 mm. The state of the cathode surface was evaluated in the same manner as in Test Example 2. The results are shown in Table 5.

From the results shown in FIG. 12, when the electrolytic solution obtained in Example 6 containing 1 mol of tetraethylammonium chloride as an additive was used for electrodeposition while adjusting the current density to 0.75 mA / cm ² [ Experiment No. 15, see FIG. 12 (A)], and using the electrolyte obtained in Example 7 containing 2 mol of tetraethylammonium chloride as an additive, the current density was adjusted to 0.5 mA / cm ² for electrodeposition. [Experiment No. 16, see FIG. 12 (B)], using the electrolytic solution obtained in Example 7 containing 2 mol of tetraethylammonium chloride as an additive, the current density was adjusted to 1 mA / cm ² and the electric current was adjusted. When analyzed (see Experiment No. 17, FIG. 12C), the electrolyte obtained in Example 3 containing no tetraethylammonium chloride as an additive was used, and the current density was 0.5 mA / When electrodeposited adjusted to m ² Experiment No. 12, FIG. 12 (D)], the aluminum plating film on the cathode surface (in the figure, see arrows) it can be seen that the.

Moreover, from the results shown in Table 5, the electrolytic solution obtained in Example 6 containing 1 mol of tetraethylammonium chloride as an additive was used for electrodeposition by adjusting the current density to 0.75 mA / cm ² . (Experiment No. 15), when using the electrolytic solution obtained in Example 7 containing 2 mol of tetraethylammonium chloride as an additive and adjusting the current density to 0.5 mA / cm ² for electrodeposition (Experiment No. 16) Using the electrolytic solution obtained in Example 7 containing 2 mol of tetraethylammonium chloride as an additive and adjusting the current density to 1 mA / cm ² for electrodeposition (Experiment No. 17) and as an additive using the obtained electrolyte solution in example 3 containing no tetraethylammonium chloride, when electrodeposited by adjusting the current density to 0.5 mA / cm ² (Test No. 12) , The cathode surface (in the figure, see arrow) aluminum plating film it can be seen that is formed. In particular, when the electrolytic solution obtained in Example 6 containing 1 mol of tetraethylammonium chloride as an additive was used for electrodeposition with the current density adjusted to 0.75 mA / cm ² (Experiment No. 15), Using the electrolytic solution obtained in Example 7 containing 2 mol of tetraethylammonium chloride as an agent, the current density was adjusted to 0.5 mA / cm ² for electrodeposition (Experiment No. 16), and tetraethylammonium as an additive When the electrolytic solution obtained in Example 3 containing no chloride was used for electrodeposition with the current density adjusted to 0.5 mA / cm ² (Experiment No. 12), a silver-white smooth surface was formed on the cathode surface. It can be seen that an aluminum plating film having s is formed.

From these results, according to the electrolytic solutions obtained in Example 6 and Example 7 containing tetraethylammonium chloride as an additive, aluminum was added in the same manner as the electrolytic solution obtained in Example 3 containing no additive. It can be seen that electrodeposition can be performed.

(2) Observation of aluminum plating film Using a scanning electron microscope [manufactured by JEOL Ltd., trade name: JSM-6510LV], the aluminum plating film obtained in Experiment No. 15 and the aluminum plating obtained in Experiment No. 12 The film and the cathode surface before electrodeposition were observed. In Test Example 4, an optical photograph of the surface of the aluminum plating film obtained in Experiment No. 12 is shown in FIG. 13A, an optical photograph of the surface of the aluminum plating film obtained in Experiment No. 15 is shown in FIG. An optical photograph of the cathode surface before analysis is shown in FIG. In the figure, the scale bar indicates 10 μm.

From the results shown in FIG. 13, it was confirmed that an electrolyte solution containing an imidazolidinone compound and an aluminum halide and having an imidazolidinone compound / aluminum halide (molar ratio) of 25/75 to 50/50 was used. When analyzed (see FIGS. 13A and 13B), it can be seen that it has a structure in which crystals are arranged. Since this structure was not found on the cathode surface before the electrodeposition (see FIG. 13C), it can be seen that the crystal is an aluminum crystal.

Further, from the results shown in FIG. 13, the aluminum plating film obtained in Experiment No. 15 compared with the size of the crystals constituting the aluminum plating film obtained in Experiment No. 12 (see FIG. 13A). It can be seen that the size of the crystals constituting the film [see FIG. 13B] is small.

From the above results, when electrodepositing was performed using the electrolytic solution obtained in Example 6 containing tetraethylammonium chloride as an additive (Experiment No. 15), the electrolytic solution obtained in Example 3 containing no additive. It can be seen that there is a tendency that an aluminum plating film having a smoother surface can be obtained than in the case of using (Experiment No. 12).

(3) Composition analysis of aluminum plating film Using an X-ray diffractometer (trade name: X'Pert Pro-MPD PW 3040/60, manufactured by PANalytical), a tube voltage of 45 kV and a tube are generated by a parallel beam of CuKα rays. The X-ray diffraction of the aluminum plating film obtained in Experiment No. 15 at a current of 40 mA was examined. In Test Example 4, X-ray diffraction of the aluminum plating film obtained in Experiment No. 15 is shown in FIG. In addition, elemental analysis of the aluminum plating film obtained in Experiment No. 15 was performed using an energy dispersive X-ray analyzer (manufactured by OXFORD INSTRUMENTS, trade name: INCAxact) attached to the scanning electron microscope. I did it. As a result, it was confirmed that this aluminum plating film was composed of 99.5 atomic% of aluminum atoms and 0.5 atomic% of chlorine. Moreover, it can be seen from the results shown in FIG. 14 that the aluminum plating film obtained in Experiment No. 15 contains aluminum atoms.

From the above results, it contains an imidazolidinone compound and an aluminum halide, an imidazolidinone compound / aluminum halide (molar ratio) is 25/75 to 50/50, and contains tetraethylammonium chloride as an additive. According to the electrolytic solution, it can be seen that an aluminum plating film having a smoother surface can be obtained.

Example 8
In a glove box kept in an argon gas atmosphere, an imidazolidinone compound (1,3-dimethyl-2-imidazolidinone) in which R ¹ and R ² are methyl groups in formula (I) and an aluminum halide ( Aluminum chloride) and an additive (triethylenetetramine) are mixed so that 1,3-dimethyl-2-imidazolidinone / aluminum chloride / triethylenetetramine (molar ratio) is 40/60/1. Got.

Test Example 5
The electrolytic solution obtained in Example 8 was placed in an electrolytic cell. Thereafter, the cathode obtained in Production Example 4 and the anode obtained in Production Example 5 were inserted into the electrolytic solution in the electrolytic cell, and the temperature of the electrolytic solution: 40 ° C., current density: 0.75 mA / cm. ² and the amount of energization: Electrodeposition was performed by constant current electrolysis energized between the anode and the cathode at 10 C / cm ² .

In Test Example 5, an optical photograph of the cathode surface after electrodeposition using the electrolytic solution obtained in Example 8 is shown in FIG. In the figure, the scale bar indicates 10 mm.

From the results shown in FIG. 15, an aluminum plating film having a smooth surface with silver white on the cathode surface when electrodeposited using an electrolytic solution containing triethylenetetramine as an additive (Example 8). It can be seen that is formed.

Therefore, an electrolytic solution containing an imidazolidinone compound and an aluminum halide, an imidazolidinone compound / aluminum halide (molar ratio) is 25/75 to 50/50, and contains triethylenetetramine as an additive. It turns out that the aluminum plating film which has a smoother surface can be obtained by using.

Example 9
In a glove box kept in an argon gas atmosphere, an imidazolidinone compound (1,3-dimethyl-2-imidazolidinone) in which R ¹ and R ² are methyl groups in formula (I) and an aluminum halide ( Aluminum chloride) and the additive (toluene) were mixed so that 1,3-dimethyl-2-imidazolidinone / aluminum chloride / toluene (molar ratio) was 40/60/120 to obtain an electrolytic solution. .

Test Example 6
(1) Cyclic voltammetry In a glove box kept in an argon gas atmosphere, the working electrode obtained in Production Example 1, the counter electrode obtained in Production Example 2, the reference electrode obtained in Production Example 3, Using the electrolytic solution obtained in Example 9, a three-electrode electrochemical cell was produced.

Using the three-electrode electrochemical cell obtained above and an electrochemical measurement system [Hokuto Denko Co., Ltd., trade name: HZ-5000], electrolyte temperature: 25 ° C., potential sweep rate: 10 mV / S and potential sweep range: cyclic voltammetry was performed under the condition of −1 to 2 V with respect to aluminum.

In Test Example 6, the results of measuring the redox potential of the electrolytic solution obtained in Example 9 by cyclic voltammetry are shown in FIG.

From the result shown in FIG. 16A, when the potential is swept from the natural potential (about 0.3 V) to the cathode side, the cathode current rises around the potential of 0 V (see arrow A in the figure). From this, it can be seen that aluminum ions in the electrolytic solution are reduced and aluminum is deposited.

Further, from the result shown in FIG. 16A, when the sweep is turned back at the potential of −1V and the potential is swept to the anode side, the rise of the anode current is observed from around the potential of 0V (see arrow B in the figure). From this, it can be seen that the precipitated aluminum is dissolved.

(2) Electrodeposition of aluminum The electrolytic solution obtained in Example 9 was put in an electrolytic cell. Thereafter, the cathode obtained in Production Example 4 and the anode obtained in Production Example 5 were inserted into the electrolytic solution in the electrolytic cell, and the electrolyte temperature: 40 ° C., current density: 1 mA / cm ² and Electrodeposition was carried out by constant current electrolysis in which current was applied between the anode and the cathode at an energization amount of 10 C / cm ² .

In Test Example 6, an optical photograph of the cathode surface after electrodeposition using the electrolytic solution obtained in Example 9 is shown in FIG. In the figure, the scale bar indicates 10 mm.

From the result shown in FIG. 16 (B), when electrodepositing using an electrolytic solution containing toluene as an additive (Example 9), an aluminum plating having a silver white color on the cathode surface and a smooth surface It can be seen that a film is formed.

Therefore, use an electrolytic solution containing an imidazolidinone compound and an aluminum halide, an imidazolidinone compound / aluminum halide (molar ratio) of 25/75 to 50/50, and toluene as an additive. It can be seen that an aluminum plating film having a smoother surface can be obtained.

Example 10
In a glove box kept in an argon gas atmosphere, an imidazolidinone compound (1,3-dimethyl-2-imidazolidinone) in which R ¹ and R ² are methyl groups in formula (I) and an aluminum halide ( (Aluminum chloride) and additive (m-xylene) are mixed so that 1,3-dimethyl-2-imidazolidinone / aluminum chloride / m-xylene (molar ratio) is 40/60/100. The electrolyte solution was obtained.

Test Example 7
After putting the electrolytic solution obtained in Example 10 into the electrolytic cell, the cathode obtained in Production Example 4 and the anode obtained in Production Example 5 were inserted into the electrolytic solution in the electrolytic cell, Electrodeposition was performed by constant-current electrolysis in which an electric current was passed between the anode and the cathode at an electrolyte temperature of 40 ° C., a current density of 1 mA / cm ² and an energization amount of 20 C / cm ² .

In Test Example 7, an optical photograph of the cathode surface after electrodeposition using the electrolytic solution obtained in Example 10 is shown in FIG. In the figure, the scale bar indicates 10 mm.

From the results shown in FIG. 17, when electrodeposition was performed using an electrolytic solution containing m-xylene as an additive (Example 10), an aluminum plating having a silver-white surface on the cathode surface and a substantially smooth surface. It can be seen that a film is formed.

It should be noted that when the electrodeposition is performed using an electrolyte containing benzene as an additive instead of using an electrolyte containing tetraethylammonium chloride, triethylenetetramine, toluene or m-xylene as an additive, Similar results are obtained when using an electrolyte containing ethylammonium chloride, triethylenetetramine, toluene or m-xylene.

Therefore, from the above results, imidazolidinone compound and aluminum halide are contained, imidazolidinone compound / aluminum halide (molar ratio) is 25 / 75-50 / 50, tetraethylammonium chloride, triethylenetetramine It can be seen that an aluminum plating film having a smoother surface can be obtained with an electrolytic solution containing a solvent such as toluene, m-xylene, or benzene.

Comparative Example 2
In Example 1, electrolysis was performed in the same manner as in Example 1 except that 1,3-dimethyl-2-imidazolidinone / aluminum chloride (molar ratio) was changed from 48.8 / 51.2 to 52/48. A liquid was obtained.

Test Example 8
(1) Cyclic voltammetry In a glove box kept in an argon gas atmosphere, the working electrode obtained in Production Example 1, the counter electrode obtained in Production Example 2, the reference electrode obtained in Production Example 3, Using the electrolytic solution obtained in Example 2 or Comparative Example 2, a three-electrode electrochemical cell was produced.

Using the three-electrode electrochemical cell obtained above and an electrochemical measurement system (manufactured by Hokuto Denko Co., Ltd., product number: HZ-5000), the temperature of the electrolyte solution: 80 ° C., sweep rate: 50 mV / s, Sweep range: Cyclic voltammetry was performed on aluminum at -4 to 2V.

In Test Example 8, the temperature of the electrolytic solution obtained in Example 2 or Comparative Example 2 was adjusted to 80 ° C., and the results of measuring the oxidation-reduction potential of the electrolytic solution by cyclic voltammetry are shown in FIG. In the figure, A is the result of measuring the redox potential of the electrolytic solution obtained in Example 2 by cyclic voltammetry, and B is the result of measuring the redox potential of the electrolytic solution obtained in Comparative Example 2 by cyclic voltammetry. Indicates.

From the results shown in FIG. 18, when the electrolytic solution obtained in Example 2 was used as the electrolytic solution (see A in the figure), the potential was swept from the natural potential (about 0.3 V) to the cathode side. In the vicinity of the potential of 0 V (see arrow (a)), the rising of the cathode current is observed, which indicates that aluminum ions in the electrolytic solution are reduced and aluminum is deposited. On the other hand, when the potential is swept to the anode side, the rising of the anode current is observed from around the potential of 0 V, indicating that the precipitated aluminum is dissolved.

On the other hand, from the result shown in FIG. 18, when the electrolytic solution obtained in Comparative Example 2 was used as the electrolytic solution (see B in the figure), the potential was changed from the natural potential (about 0.3 V) to the cathode side. From the fact that no cathode current rises near the potential of 0 V, it can be seen that no aluminum is deposited. In addition, when the potential is swept to the anode side, no rising of the anode current is observed near the potential of 0 V, which indicates that aluminum is not present on the working electrode. From these results, when using an electrolytic solution having a 1,3-dimethyl-2-imidazolidinone / aluminum chloride (molar ratio) of 52/48, the reduction of aluminum ions and the oxidation of aluminum cannot be performed. I understand.

As described above, an electrolytic solution containing an imidazolidinone compound and an aluminum halide and having an imidazolidinone compound / aluminum halide (molar ratio) of 25/75 to 50/50 is easy to handle. It can be used as an electrolytic solution for aluminum secondary batteries, production of aluminum materials, formation of aluminum plating film on the surface of the object to be plated, etc. Therefore, for example, it is expected to be used for development of secondary batteries for use in portable devices, electric vehicles, and the like, development of inexpensive, high-strength structural members, and the like.

Claims

Formula (I):

(Wherein R 1 and R 2 are each independently a hydrogen atom, a halogen atom, a nitro group, an amino group, a carboxyl group, a hydroxyl group, an optionally substituted alkyl group having 1 to 4 carbon atoms, An optionally substituted alkenyl group having 2 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 13 carbon atoms, or 1 to 4 carbon atoms Represents an alkoxycarbonyl group of
An aluminum halide is dissolved in the imidazolidinone compound represented by formula (I), and the molar ratio of the imidazolidinone compound represented by formula (I) to the aluminum halide [imidazolidinone compound / aluminum halide] is 25/75. Electrolytic solution for aluminum plating that is 50/50.
An object to be plated is immersed in the electrolytic solution for aluminum plating according to claim 1, and aluminum is electrodeposited on the surface of the object to be plated from the electrolytic solution for aluminum plating to form an aluminum plating film. A method for producing an aluminum material.
Formula (I):

(Wherein R 1 and R 2 are each independently a hydrogen atom, a halogen atom, a nitro group, an amino group, a carboxyl group, a hydroxyl group, an optionally substituted alkyl group having 1 to 4 carbon atoms, An optionally substituted alkenyl group having 2 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 13 carbon atoms, or 1 to 4 carbon atoms Represents an alkoxycarbonyl group of
An aluminum halide is dissolved in the imidazolidinone compound represented by formula (I), and the molar ratio of the imidazolidinone compound represented by formula (I) to the aluminum halide [imidazolidinone compound / aluminum halide] is 25/75. An electrolytic solution for an aluminum secondary battery that is 50/50.