JP2018031025A - CRYSTALLINE ELECTROLYTIC Al-Mn ALLOY FOIL AND MANUFACTURING METHOD THEREFOR - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crystalline Al-Mn alloy foil excellent in tensile strength than Al alloy foils manufactured by conventional electrolysis and a manufacturing method therefor.SOLUTION: There are provided a crystalline electrolytic Al-Mn alloy foil having Mn content of 0.1 to 20.0 mass%, a crystal particle diameter of 10.0 μm or less, tensile strength of 50 MPa or more and thickness of 5 to 20 μm, and a manufacturing method of the crystalline electrolytic Al-Mn alloy foil, including a process for electrodepositing Al-Mn alloy foil on a cathode using molten salt as an electrolyte and a process for detaching and recovering electrodeposited Al-Mn alloy foil, and the electrolyte contains alkylimidazolium halide or alkylpyridinium halide, a molten salt consisting of a mixture of aluminum halide, and an additive of manganese halide.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a crystalline electrolytic aluminum-manganese alloy foil and a method for producing the same, and more particularly to a foil containing manganese in an electrolytic aluminum foil and a method for producing the same in order to improve tensile strength.

  In recent years, lithium ion batteries have been developed as batteries for automobiles and personal computers, and aluminum foil is used as the positive electrode current collector. Conventionally, in order to increase the battery capacity by applying more active material, it is desired to make the current collector thinner. The details of the current collector aluminum foil are described below, but aluminum may be described as Al and manganese as Mn.

  Al foil is conventionally manufactured by rolling Al foil. The lower limit of the thickness of the Al foil produced by such a rolling method is usually about 10 μm. In order to further increase the battery capacity of the lithium ion battery and reduce the size, it is preferable to use an aluminum foil that is as thin as possible, for example, 5 to 10 μm thick. Further, as the thickness of the foil is reduced, an aluminum foil that is superior in mechanical properties than the conventional one is required. Although such an Al thin foil can be manufactured by a rolling method, there is a problem that the manufacturing cost becomes high because it is necessary to increase the number of rolling processes.

  Patent Document 1 describes a method for producing an aluminum foil by an electrolytic method. However, it is difficult to increase the strength of the pure Al foil produced by the electrolytic method because it does not undergo heat treatment or work hardening unlike the rolling method. Therefore, an electrolytic Al foil excellent in mechanical properties and a method for producing the same are desired.

  Electrolytic bath composition is important when producing metal films by electrolysis, and electrolytic baths that have been put to practical use and used industrially use additives to improve the quality and function of metal films. Has been. Among the additives, it is well known that an alloy film can be produced by the electrolytic method by adding a metal salt. By alloying the metal film, mechanical properties are improved by solid solution strengthening and crystal grain refinement. Can be expected. However, the alloy electrodeposited film has a problem that it is easily amorphous and the metal film is hard and brittle.

  Alloying is effective for producing industrially required thin and high-strength foils. In particular, Al-Mn alloy foils that have been put to practical use as high-strength rolled foils are also effective in electrolytic foils. Conceivable. However, since the manufacturing method is greatly different between the rolling method and the electrolytic method, there remains a problem that the electrolytic Al—Mn alloy foil cannot be easily manufactured.

JP 2014-80632 A

The present invention has been made in view of the above circumstances, and the present inventors perform crystalline alloy electrodeposition on a cathode having an appropriate surface roughness, and peel and collect only the electrodeposited film. The present inventors have found an electrolytic Al foil excellent in tensile strength and a method for producing the same, and completed the present invention.

  The present invention according to claim 1, wherein the Mn content is 0.1 to 20.0 mass%, the crystal grain size is 10.0 μm or less, the tensile strength is 50 MPa or more, and the thickness is 5 to 20 μm. A crystalline electrolytic Al-Mn alloy foil characterized by having a thickness is obtained.

  The present invention provides, in claim 2, a method for producing the crystalline electrolytic Al-Mn alloy foil according to claim 1, wherein the Al-Mn alloy foil is electrodeposited on the cathode using a molten salt as an electrolyte. And a step of peeling and recovering the electrodeposited Al-Mn alloy foil, wherein the electrolytic solution is a molten salt composed of a mixture of an alkylimidazolium halide or an alkylpyridinium halide and an aluminum halide; A crystalline electrolytic Al-Mn alloy foil characterized by containing a chemical additive.

According to a third aspect of the present invention, in the second aspect of the present invention, in the electrodeposition step, the concentration of manganese halide in the electrolytic solution is 0.5 to 80 mM, the temperature of the electrolytic solution is 10 to 150 ° C., and the current density Of 10 to 400 mA / cm ² .

According to a fourth aspect of the present invention, in the second aspect of the present invention, in the electrodeposition step, the concentration of manganese halide in the electrolytic solution is more than 80 mM and not more than 100 mM, the temperature of the electrolytic solution is 10 to 150 ° C., and the current density There was assumed to be less than 10 mA / cm ² or more 30 mA / cm ^2.

  According to a fifth aspect of the present invention, in any one of the second to fourth aspects, the surface of the cathode is subjected to a mechanical polishing process, an electrolytic polishing process, or a chemical polishing process.

  According to the present invention, it is possible to provide a crystalline electrolytic Al-Mn alloy foil having a tensile strength superior to that of a conventional electrolytic aluminum foil and a method for producing the same.

It is a graph which shows the XRD measurement result in the Example of the Al-Mn alloy foil which concerns on this invention. It is a SEM photograph in the example of the Al-Mn alloy foil concerning the present invention. It is a stress-strain diagram in the Example of the Al-Mn alloy foil which concerns on this invention.

1. Electrolytic Al—Mn Alloy Foil The crystalline electrolytic Al—Mn alloy foil according to the present invention has a Mn content of 0.1 to 20.0 mass% (hereinafter, simply referred to as “%”) and 10.0 μm or less. And a tensile strength of 50 MPa or more, and a thickness of 5 to 20 μm.

1-1. Alloy composition The Mn content in this electrolytic Al-Mn alloy foil is defined as 0.1 to 20.0%. When the Mn content is less than 0.1%, it becomes difficult to produce an Al—Mn alloy foil by electrolysis due to the coarsening of the crystal grain size. On the other hand, when the Mn content exceeds 20.0%, the foil becomes amorphous and brittle rather than crystalline. The Mn content is preferably 1.0 to 10.0%.

  Al-Mn alloys are classified as 3000 series non-heat-treatable alloys. An alloy having high strength without reducing the workability and corrosion resistance of pure aluminum, specifically, 3003 and 3004 are typical. Widely used in containers such as aluminum cans and housing exteriors. Also in the rolled aluminum foil, an Al-Mn alloy foil is manufactured as a high-strength foil. Compared with a rolled product, an Al—Mn alloy produced by an electrodeposition method is characterized in that the amount of Mn solid solution increases. However, as described above, since the crystallinity changes when a large amount of Mn is dissolved, it is preferable that the Mn content is 0.1 to 20.0%, preferably 1.0 to 10.0%. .

1-2. Crystal grain size The crystal grain size in this electrolytic Al-Mn alloy foil is defined as 10.0 μm or less. When this crystal grain size exceeds 10.0 μm, the gap between the crystal grains becomes large, leading to a decrease in strength. The crystal grain size is preferably 8.0 μm or less. The lower limit of the crystal grain size is not particularly limited, but is naturally determined by the manufacturing method, and is about 2.0 μm in the present invention.

1-3. Tensile strength The tensile strength in this electrolytic Al-Mn alloy foil is specified to be 50 MPa or more. When the tensile strength is less than 50 MPa, it becomes difficult to use as a battery current collector foil. The tensile strength is preferably 70 MPa or more. The upper limit value of the tensile strength is not particularly limited, but is naturally determined by the manufacturing method, and is about 100 MPa in the present invention.

1-4. Foil Thickness The thickness of this electrolytic Al—Mn alloy foil is specified to be 5 to 20 μm. It is difficult to produce an electrolytic foil having a thickness of less than 5 μm, and the strength is low and it cannot be used. On the other hand, if the thickness exceeds 20 μm, it is too thick to be used appropriately for a battery current collector foil or the like.

2. Method for Producing Electrolytic Al-Mn Alloy Foil The method for producing electrolytic Al-Mn alloy foil according to the present invention is an electrolytic Al-Mn alloy foil produced by performing electrodeposition under appropriate conditions using an electrolytic solution and a titanium cathode. Is peeled and collected. Below, the requirements which comprise this invention and the reason for limitation are demonstrated.

2-1. Electrolysis First, electrolysis used in the method for producing an electrolytic Al—Mn alloy foil according to the present invention will be described. For this electrolysis, an electrolytic cell containing an electrolytic solution is prepared, the cathode and the anode are arranged facing each other in the electrolytic solution, and a direct current is passed between both electrodes, whereby an Al-Mn alloy is charged on the cathode surface. To analyze. When supplying the Al source from the anode, it is preferable to use an aluminum anode, and when supplying the Al source from the bath, it is preferable to use an insoluble anode. Moreover, the shape of a cathode and an anode uses a plate-shaped thing and a drum-shaped thing.

2-2. Electrolyte The standard electrode potential of aluminum is -1.662 Vvs. As is understood from SHE, it is usually impossible to deposit aluminum from an aqueous solution. Therefore, as an electrolytic solution for electrodepositing aluminum, a molten salt as a mixture with an aluminum salt or an organic solvent in which an aluminum salt is dissolved is used.

Molten salts can be broadly classified into inorganic molten salts and organic room temperature molten salts. As the organic room-temperature molten salt, a molten salt composed of a mixture of an alkylimidazolium halide and an aluminum halide, or a molten salt composed of a mixture of an alkylpyridinium halide and an aluminum halide is preferably used. Here, as the alkyl imidazolium halide, 1-ethyl-3-methylimidazolium chloride (hereinafter referred to as “EMIC”) is preferably used. As the alkylpyridinium halide, 1-butylpyridinium chloride (hereinafter referred to as “BPC”) is preferably used. Furthermore, aluminum chloride (hereinafter referred to as “AlCl ₃ ”) is preferably used as the aluminum halide. Depending on the composition, the melting point of EMIC and AlCl ₃ decreases to the vicinity of −50 ° C., and the melting point of BPC and AlCl ₃ also decreases to the vicinity of −50 ° C. depending on the composition. By using an organic room temperature molten salt as the liquid, electrodeposition of aluminum can be performed in a lower temperature environment. From the viewpoint of the viscosity and conductivity of the electrolyte, a combination of EMIC and aluminum chloride is most preferable. The molar ratio of EMIC and _{AlCl 3 (EMIC: AlCl 3)} , and the molar ratio of BPC and AlCl ₃ (BPC: AlCl ₃₎ Both 2: 1 to 1: it is preferable to be 2, 1 : 1 to 1: 2 is more preferable.

In order to deposit the Al—Mn alloy, a metal salt of Mn is added to the electrolytic solution. As such a metal salt of Mn, a manganese halide is preferably used. The manganese halide is preferably manganese chloride (hereinafter referred to as “MnCl ₂ ”). This is because MnCl ₂ easily dissolves in the molten salt composed of EMIC and AlCl ₃ or BPC and AlCl ₃ . The higher the concentration of manganese halide in the electrolytic solution, the higher the Mn content in the Al-Mn alloy foil that is electrodeposited. However, as the amorphous state proceeds, the hard and brittle electrodeposits Become. Therefore, the concentration of manganese halide in the electrolytic solution is adjusted so that a crystalline electrodeposit having a Mn content of 20% or less in the electrodeposit is obtained. In addition, the density | concentration of the manganese halide in electrolyte solution becomes like this. Preferably it is 0.5-100 mM, More preferably, it is 0.5-80 mM. In addition, when the concentration of manganese halide in the electrolytic solution is in the range of 0.5 to 80 mM, all current densities within the range defined by the present invention can be used. However, when the concentration of manganese halide in the electrolytic solution is more than 80 mM and not more than 100 mM, the current density within the range defined in the present invention may not be used. As described later, the current density is 10 mA. / Cm ² or more and less than 30 mA / cm ² is preferable. The unit of concentration mM is equal to 10 ⁻³ mol / L.

2-3. Electrodeposition conditions Next, the electrodeposition conditions will be described. First, the electrodeposition temperature, that is, the temperature of the electrolytic solution in electrodeposition is preferably within the range of 10 to 150 ° C. When the electrolyte temperature is lower than 10 ° C., the viscosity of the electrolyte increases and the electrical resistance increases, so the maximum current density decreases. As a result, the electrodeposition efficiency is lowered, and problems such as aluminum precipitation tend to be non-uniform. On the other hand, when the electrolytic solution temperature exceeds 150 ° C., volatilization of aluminum halide such as aluminum chloride and decomposition of EMI ⁺ cation and BPC ⁺ cation become remarkable, and the desired electrolytic solution composition becomes unstable. Further, the energy for maintaining the temperature is increased and the deterioration of the electrolytic cell is promoted, so that the production efficiency is lowered. A more preferable electrolyte temperature is in the range of 25 ° C. to 100 ° C. near room temperature.

Next, the current density of direct current as an electrodeposition condition will be described. The current density is preferably 10 to 400 mA / cm ² , more preferably 20 to 200 mA / cm ² . Since the electrodeposition rate depends on the current density, if it is less than 10 mA / cm ² , the electrodeposition rate is too slow, leading to a decrease in production efficiency. On the other hand, the electrical resistance of the constraints of the electrolyte, it is difficult to current density of more than 400 mA / cm ^2, for example 400 mA / cm ² to be too large electrostatic析速degree exceeds, electrodeposited film is uneven It is easy to become. Further, it has been confirmed that the Mn content in the electrodeposits increases with the current density when the current density is in the range of 40 mA / cm ² or less. Within this range, it is necessary to adjust both the MnCl ₂ addition amount and the current density so that the Mn content in the electrodeposits falls within the range defined by the present invention. In particular, when the concentration of manganese halide in the electrolyte is 100mM exceed 80mM, the current density is preferably less than 10 mA / cm ² or more 30 mA / cm ^2.

2-4. Cathode and Anode For the cathode for electrolysis used in the method for producing an Al—Mn alloy foil according to the present invention, titanium, stainless steel, nickel, carbon and the like are suitably used. Metals such as titanium, stainless steel, and nickel are excellent in corrosion resistance because a dense natural oxide film is formed on the surface. On the other hand, since there is a natural oxide film, the adhesion with the electrodeposited film is lowered, so that it is suitable as a cathode in the production of electrolytic copper foil and electrolytic Al foil. A non-metallic material such as carbon is suitable as a cathode because of its low bonding strength with the plating film. If a high peak or a deep valley exists on a part of the surface of the cathode, aluminum deposited in this valley will bite in the aluminum electrodeposition. And when peeling | extruding the electrodeposited aluminum deposited, big peeling resistance generate | occur | produces and, thereby, an electrolytic Al-Mn alloy foil is damaged or cut | disconnected.

  Such peeling resistance is affected by the surface roughness of the cathode. In the present invention, arithmetic average roughness (Ra) and ten-point average roughness (Rz) are employed as indices representing the surface roughness. As a result, the peel resistance is reduced, and the electrodeposited Al-Mn alloy foil is easily peeled and collected from the cathode.

  Ra is extracted from the roughness curve by the reference length in the direction of the average line, the absolute values of deviations from the average line of the extracted part to the measurement curve are summed, and the average value is expressed in micrometers (μm). Is. In the present invention, Ra is defined as 0.10 to 0.40 μm. In order to make Ra less than 0.10 μm, the electrolysis process takes a long time, so the electrolysis efficiency decreases. On the other hand, when Ra exceeds 0.40 μm, it becomes difficult to peel off and aluminum cannot be recovered, and the peelability, appearance, and uniformity of the Al—Mn alloy foil cannot be achieved. Ra is preferably 0.15 to 0.30 μm.

  Rz is extracted from the roughness curve only in the direction of the average line, measured in the direction of the vertical magnification from the average line of the extracted part, and the altitude (Yp) of the highest peak from the highest peak to the fifth peak. The sum of the average value of the absolute values and the average value of the absolute values of the altitudes (Yv) of the bottom valley from the lowest valley bottom to the fifth is obtained, and this value is expressed in micrometers (μm). Rz is an index representing the degree and number of high peaks and deep valleys, and is a particularly important index of surface roughness in the present invention. In the present invention, Rz is defined as 0.20 to 0.70 μm. When Rz is less than 0.20 μm, the releasability is too good, and the Al—Mn alloy foil peels off during electrolysis, so the uniformity of the Al—Mn alloy foil is poor. On the other hand, when Rz exceeds 0.70 μm, grain boundaries and cracks are generated in the electrodeposited Al—Mn alloy foil, resulting in quality degradation, and the peelability, appearance, and uniformity of the Al—Mn alloy foil cannot be achieved. . Rz is preferably 0.25 to 0.50 μm. Since such peeling resistance is affected by the surface roughness of the cathode, the arithmetic average roughness (Ra) is 0.10 to 0.40 μm, and the ten-point average roughness (Rz) is 0.20 to 0.70 μm. Is preferable.

  In order to adjust the surface roughness Ra and Rz of the cathode as described above, electrolytic polishing treatment, mechanical polishing treatment, and chemical polishing treatment are used in the present invention. The electrolytic polishing treatment is preferable in that the surface roughness can be controlled with high accuracy.

  Electropolishing is a technique for smoothing a metal surface by utilizing the difference in dissolution rate between a convex portion and a concave portion of the metal surface when an electric current is passed through the metal immersed in the polishing liquid. The electropolishing treatment can be performed using an ethylene glycol solution of NaCl or an ethylene glycol solution of KCl. The cathode is immersed in these solutions, and the surface is polished into a mirror surface by applying a voltage thereto and ultrasonic cleaning. Polishing is performed more effectively by combining high voltage electrolysis corresponding to rough polishing and low voltage electrolysis corresponding to finish polishing. Further, Ra and Rz can be adjusted by the processing time, that is, the voltage application time. The preferable electrolysis voltage and treatment time for high voltage electrolysis are 15 to 60 V for 30 seconds to 5 minutes, and the more preferred electrolysis voltage and treatment time is 20 to 40 V for 1 to 3 minutes. The preferable electrolysis voltage and treatment time for low-voltage electrolysis are 6 to 15 V and 5 to 60 minutes, and the more preferred electrolysis voltage and treatment time are 8 to 12 V and 10 to 30 minutes. For the combination, for example, ultrasonic cleaning after removing dirt and oxide film on the surface layer by the first high-voltage electrolysis, and then alternately performing low-voltage electrolysis and ultrasonic cleaning following high-voltage electrolysis and ultrasonic cleaning. Thus, mirror polishing excellent in smoothness can be performed.

  As the mechanical polishing treatment, normal buffing or the like can be used. However, it may be difficult to obtain a high degree of smoothness of the cathode, and fine scratches may remain on the surface. A chemical polishing process such as etching can also be used, but the polished surface may be uneven.

The material of the aluminum anode used when supplying the Al source from the anode is not particularly limited, but 99 to 99.999% pure Al is preferably used. When supplying the Al source from the bath, an Al-Mn alloy foil can be continuously produced by using an insoluble electrode and supplying an aluminum halide such as AlCl ₃ . The material of the insoluble electrode is not particularly limited, but an insoluble metal material in which the surface of a valve metal such as titanium is coated with a conductive electrode substance containing a platinum group or its oxide is preferably used.

2-5. Separation and recovery of electrodeposited aluminum foil In order to recover the aluminum electrodeposited on the cathode as described above, a cathode drum is preferably used. The Al—Mn alloy foil electrodeposited on the drum surface is peeled off, wound around a collecting drum, and continuously collected. As a recovery method, for example, after the cathode drum is first stopped and grown to a predetermined foil thickness, electrodeposition is temporarily interrupted, the cathode drum is rotated, and the exposed Al-Mn alloy foil is peeled off. Examples of the method include a method of sticking on a collecting drum and winding it while laminating, and a method of collecting as a peeled piece simultaneously with peeling. In addition, although the thickness of the Al-Mn alloy foil obtained by this invention covers the wide range of 1 micrometer-20 micrometers normally, what is necessary is just to select the thickness suitably according to a use. For example, when used as a positive electrode current collector of a lithium ion battery, the thickness is preferably 8 to 12 μm.

  EXAMPLES Next, although this invention is demonstrated further in detail based on an Example, this invention is not limited to these.

<Electrodeposition of Al-Mn alloy foil>
According to the following procedure, an Al—Mn alloy was formed on the surface of the titanium cathode by electrodeposition. However, a copper cathode was used only for the XRD measurement sample.

The electrolytic solution and electrodeposition conditions are shown in Tables 1 and 2. As for the electrolytic solution, the concentration of MnCl _{2 in} the electrolytic solution is 0.5% when mixed at a molar ratio of EMIC: AlCl ₃ = 33: 67 or mixed at the molar ratio of BPC: AlCl ₃ = 33: 67. Each was added so as to be ˜200 mM. The electrolytic solution thus prepared was put into an electrolytic cell, and in the electrolytic solution, a titanium plate (width 30 mm, length 60 mm) or a copper plate (width 30 mm, length 60 mm) as a cathode and 99.9% as an anode. An aluminum plate (width 50 mm, length 60 mm) was placed. Here, the aluminum plate of the anode was disposed so as to face the titanium cathode so as to have a substantially constant interelectrode distance. Moreover, the titanium plate or the copper plate was masked with a PTFE tape so that the electrodeposition area was 20 × 20 mm ² .

Regarding the electrodeposition conditions, the current density is 10 to 400 mA / cm ² , the temperature is 8 to 155 ° C., and the electrodeposition time is set so that the desired foil thickness (4 to 22 μm) is obtained at each current density and temperature. The Al—Mn alloy foil was electrodeposited on the surface of a titanium cathode or a copper cathode by adjusting and performing direct current electrolysis. A magnetic stirrer was used for stirring the electrolytic solution. After such an electrolysis operation, the Al—Mn alloy foil electrodeposited on the surface of the titanium cathode or the copper cathode was washed with acetone and pure water. Thereafter, only the Al—Mn alloy foil electrodeposited on the titanium cathode was peeled off and collected from the titanium cathode using tweezers, and used as a sample of the electrodeposit.

  The following evaluation was performed about the Al-Mn alloy foil sample produced as mentioned above.

<Mn content>
The Mn content in the sample was measured by surface analysis and point analysis using EPMA (manufactured by JEOL, JXA-8200 type). The results are shown in Tables 1 and 2.

<Evaluation of crystallinity>
The crystallinity of the sample was evaluated by XRD (manufactured by Rigaku, RIX3100). As shown in FIG. 1 (a) (result of the present invention example 8 described later), a crystal having a sharp Al peak is obtained, and as shown in FIG. 1 (b) (result of comparative example 6 described later) Al (111). Those having a broad peak as described above were crystalline + amorphous, and those having an Al peak disappeared as shown in (c) (results of Comparative Example 10 described later) were regarded as amorphous. The results are shown in Tables 1 and 2.

<Calculation of crystal grain size>
The average particle size was calculated from an SEM (manufactured by JEOL) image. Specifically, a line having an arbitrary length was drawn in the SEM image and divided by the number of crystal grains was calculated as the average grain size. However, as shown in FIG. 2, unlike crystalline (a), crystalline + amorphous (b) and amorphous (c) are not calculated because they include amorphous. The results are shown in Table 3. In addition, the SEM image of the said invention example 8, the comparative example 6, and the comparative example 10 is shown in FIG.

<Determination of whether or not a tensile specimen can be produced>
A foil having a size of 20 × 20 cm ² as the electrodeposition area was collected, ○, which was peeled off in the electrolyte during the electrodeposition and could not be recovered, and cracked at the time of collection, 20 × 20 cm Those that could not be recovered as foil ² were marked with x. The results are shown in Tables 1 and 2.

<Tensile strength>
From the determination result, a tensile test was performed on a crystalline sample determined to be capable of producing a tensile test piece. The shape of the test piece used for the tensile test was a strip-shaped test piece having a length of 20 mm and a width of 5 mm, and an AGI-50kN manufactured by Shimadzu Corporation was used at room temperature under a tensile speed of 0.5 mm / min. I did it. The maximum stress was read from the stress-strain diagram obtained by the tensile test, and this was taken as the tensile strength. The results are shown in Tables 1 and 2.

<Comprehensive evaluation>
Electrodeposition and preparation of tensile test pieces are both possible, and the foil thicknesses shown in Tables 1 and 2 and the Mn content, crystallinity, crystal grain size and tensile strength shown in Table 3 are all present in the present invention. The comprehensive evaluation was determined to pass (◯), and the case where at least one of them was not satisfied was determined to be rejected (×). The results are shown in Tables 1 and 2.

  In Inventive Examples 1 to 22, the Mn content, crystallinity, crystal grain size, and tensile strength in the Al—Mn alloy foil were within the ranges defined in the present invention, and thus the overall evaluation was acceptable.

  In particular, under the conditions of Invention Examples 8 and 9, foils having a tensile strength exceeding 100 MPa were obtained. In addition, although the stress-strain diagram in the invention example 8 is shown in FIG. 3, it turns out that tensile strength is excellent compared with the below-mentioned comparative examples 3 and 17.

In Comparative Examples 1 to 4, since MnCl ₂ was not contained in the electrolytic solution used, the obtained foil was pure Al not containing Mn, and the tensile strength was as low as less than 50 MPa. As a result, the overall evaluation was rejected. In addition, although the stress-strain diagram of the comparative example 3 is shown in FIG. 3, it turns out that tensile strength is inferior compared with the example 8 of this invention.

In Comparative Examples 5 and 6, the amount of MnCl ₂ added in the electrolyte used was 100 mM, and the current density was too large for this condition, so the Mn content in the obtained foil was 20%. The crystallinity became crystalline + amorphous, and a tensile test piece could not be produced due to peeling during electrodeposition and cracking during recovery. As a result, the overall evaluation was rejected.

In Comparative Example 7, since the amount of MnCl ₂ added in the electrolytic solution used was too much as 200 mM, the Mn content in the obtained foil slightly exceeded 20%, the crystallinity became crystalline + amorphous, A tensile test piece could not be produced due to peeling during electrodeposition and cracking during recovery. As a result, the overall evaluation was rejected.

In Comparative Examples 8 to 10, since the amount of MnCl ₂ added in the electrolytic solution used was too much as 200 mM, the Mn content in the obtained foil exceeded 20%, the crystallinity became amorphous, and during electrodeposition A tensile test piece could not be produced due to peeling and cracking during recovery. As a result, the overall evaluation was rejected.

  In Comparative Example 11, since the current density in electrodeposition was too small, it took too much time for electrodeposition, peeling occurred during electrodeposition, and a tensile test piece could not be produced due to cracking during collection. As a result, the overall evaluation was rejected.

  In Comparative Example 12, since the current density in electrodeposition was too large, a crystalline foil was obtained, but the tensile strength was low, less than 50 MPa. As a result, the overall evaluation was rejected.

  In Comparative Example 13, since the foil thickness was too thin, a tensile test piece could not be produced due to peeling during electrodeposition and cracking during recovery. As a result, the overall evaluation was rejected.

  In Comparative Example 14, since the foil thickness was too thick, electrodeposition was possible if it took a long time, but it was unsuitable as a current collector application of a lithium ion battery because it led to deterioration of battery capacity, and the overall evaluation failed. It became.

  In Comparative Example 15, the temperature of the electrolyte was too low to increase its electrical resistance, and electrodeposition was impossible.

  In Comparative Example 16, the temperature of the electrolytic solution was too high, so that the decomposition became significant and electrodeposition was impossible.

  According to the present invention, an electrolytic Al—Mn alloy thin foil having excellent tensile strength can be produced, and an industrially significant effect can be obtained.

Claims (5)

  The Mn content is 0.1 to 20.0 mass%, the crystal grain size is 10.0 μm or less, the tensile strength is 50 MPa or more, and the thickness is 5 to 20 μm. Crystalline electrolytic Al-Mn alloy foil.   A method for producing a crystalline electrolytic Al-Mn alloy foil according to claim 1, wherein a step of electrodepositing an Al-Mn alloy foil on a cathode using a molten salt as an electrolyte and an electrodeposited Al-- A step of stripping and recovering the Mn alloy foil, wherein the electrolyte contains a molten salt composed of a mixture of alkylimidazolium halide or alkylpyridinium halide and aluminum halide; and an additive for manganese halide; A method for producing a crystalline electrolytic Al-Mn alloy foil characterized by comprising: In the electrodeposition step, the concentration of manganese halide in the electrolytic solution is 0.5 to 80 mM, the temperature of the electrolytic solution is 10 to 150 ° C, and the current density is 10 to 400 mA / cm ^2. 2. A method for producing a crystalline electrolytic Al—Mn alloy foil according to 2. In the electrodeposition step, the concentration of manganese halide in the electrolytic solution is not more than 100mM exceeded 80 mM, the temperature of the electrolytic solution is 10 to 150 ° C., a current density of less than 10 mA / cm ² or more 30 mA / cm ² The manufacturing method of the crystalline electrolytic Al-Mn alloy foil of Claim 2 which exists.   The method for producing a crystalline electrolytic Al-Mn alloy foil according to any one of claims 2 to 4, wherein the surface of the cathode is subjected to mechanical polishing treatment, electrolytic polishing treatment or chemical polishing treatment.