KR102452103B1 - Method of preparing manganese difluoride using ionic liquid and method of preparing anode for lithium ion battery comprising same - Google Patents

Abstract

The present invention comprises the steps of (a) mixing an ionic liquid having a fluorine atom (F) and a manganese precursor to prepare a mixed solution containing the ionic liquid and a manganese precursor; and (b) reacting the ionic liquid with the manganese precursor to prepare manganese difluoride _{(MnF 2 )} ; The manufacturing method of manganese difluoride of the present invention can produce manganese difluoride having high crystallinity and a large specific surface area by using an ionic liquid and microwaves.

Description

Method for manufacturing manganese difluoride using an ionic liquid and a method for manufacturing an anode material for a lithium ion battery comprising the same

The present invention relates to a method for manufacturing manganese difluoride and a method for manufacturing a negative electrode material for a lithium ion battery comprising the same, and more particularly, to manganese difluoride having high crystallinity and a large specific surface area by using an ionic liquid and microwaves. It relates to a manufacturing method of manganese difluoride capable of manufacturing and to a manufacturing method for a negative electrode material for a lithium ion battery comprising the same.

Recently, the use of lithium batteries has expanded beyond the main power sources of small electronic devices such as mobile phones and laptops to electric vehicles and power storage devices. As described above, the range of use of lithium batteries as an electrochemical energy storage medium is diversifying, and lithium batteries with low capacity reduction even during frequent charging and discharging are required. Currently, graphite, a carbon-based material with good lifespan characteristics, is commercially available as an anode active material used in lithium batteries, but the theoretical capacity is very low as 372 mAh/g, and the solid electrolyte film formed on the surface of the active material during charging and discharging is the same as that of lithium batteries. It creates safety issues. Many studies have been conducted to replace graphite, which has problems with such low capacity and safety, typically TiO ₂ , Li ₄ Ti ₅ O ₁₂ , KNb ₅ O ₁₃ , Fe ₂ O ₃ , Co ₃ O ₄ , MnO ₂ , MoO ₂ , MoO ₃ , NiO, and research using a metal oxide that undergoes an insertion (conversion) reaction, such as CuO, as an anode active material is in progress.

However, metal oxides that undergo intercalation reactions such as TiO ₂ , Li ₄ Ti ₅ O ₁₂ , and KNb ₅ O ₁₃ have a limited theoretical capacity, and Fe ₂ O ₃ , Co ₃ O ₄ , MnO ₂ etc. The transfer rate is limited and the active material is electrically isolated in the electrode with volume expansion during reaction with lithium, resulting in low rate characteristics. Therefore, it is required to introduce an anode active material capable of realizing a lithium battery having high capacity and high stability characteristics in order to solve this problem.

An object of the present invention is to provide a method for manufacturing manganese difluoride capable of producing manganese difluoride having high crystallinity and a large specific surface area by using the ionic liquid and microwaves of the present invention.

It is also an object of the present invention to use manganese difluoride prepared according to the method for manufacturing manganese difluoride as an anode material of a lithium ion battery, thereby improving the charge/discharge capacity and cycle characteristics of a lithium ion battery. to provide a way.

According to one aspect of the present invention, (a) mixing an ionic liquid having a fluorine atom (F) and a manganese precursor to prepare a mixed solution containing the ionic liquid and the manganese precursor; and (b) reacting the ionic liquid with the manganese precursor to prepare manganese difluoride _{(MnF 2 )} ;

The reaction of step (b) may be performed by irradiating the mixed solution with microwaves.

The reaction of step (b) may be carried out at a temperature of 100 to 200 ℃.

The microwave irradiation time may be 10 seconds to 3600 seconds.

The manganese precursor concentration of the mixed solution may be 0.01 to 2.5M.

The manganese difluoride may have a rod shape.

Step (a) comprises the steps of (a-1) melting the manganese precursor; and (a-2) mixing the molten manganese precursor with an ionic liquid having a fluorine atom (F) to prepare a mixed solution containing the ionic liquid and the manganese precursor.

The ionic liquid may be a compound represented by Structural Formula 1.

[Structural Formula 1]

In Structural Formula 1,

,

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, 또는

이고, X is

,

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ego,

R ₁ , R _{2 ,} R ₃ , and R ₄ are the same as or different from each other, and each independently represent a hydrogen atom, a C1 to C15 alkyl group, a C1 to C15 fluoroalkyl group, or a C2 to C15 alkenyl group. C6 to C16 aryl group, C7 to C16 arylalkyl group, or C7 to C16 alkylaryl group,

) 또는 헥사플루오로포스페이트(

)이다.Y is tetrafluoroborate (

) or hexafluorophosphate (

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로 이루어진 군으로부터 선택된 1종 이상을 포함할 수 있다.wherein X is

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It may include one or more selected from the group consisting of.

The ionic liquid is EMIM BF4 (1-Ethyl-3-methylimidazolium tetrafluoroborate), BMIM BF4 (1-Butyl-3-methylimidazolium tetrafluoroborate), and OMIM BF4 (1-Methyl-3-octyl-imidazolium-tetrafluoroborate) It may include one or more selected from.

The mixed solution may further include a compound represented by Structural Formula 2 below.

[Structural Formula 2]

in Structural Formula 2

R ₅ is a C1 to C6 alkylene group,

n is an integer from 1 to 1,000.

The compound represented by Structural Formula 2 may be ethylene glycol.

A volume ratio (A:B) of the ionic liquid (A) and the compound (B) represented by Structural Formula 2 in the mixed solution may be 10:90 to 50:50.

The manganese precursor may include a manganese salt.

The manganese salt is manganese nitrate (Manganese(II) nitrate, Mn(NO ₃ ) ₂ ), manganese acetate (Manganese(II) acetate, Mn(CH ₃ COO) ₂ ), manganese sulfate (Manganese(II) sulfate, MnSO ₄ ) ), Manganese(II) chloride, MnCl2), Manganese(II) hydroxide, Mn(OH) ₂ ), Manganese(II) sulfide, MnS), Manganese(II) carbonate , MnCO ₃ ), manganese bromide (Manganese(II) bromide, MnBr ₂ ), manganese perchlorate (Manganese(II) Perchlorate, Mn(ClO ₄ ) ₂ ) and at least one selected from the group consisting of hydrates thereof. have.

According to another aspect of the present invention, (1) mixing an ionic liquid having a fluorine atom (F) and a manganese precursor to obtain a mixed solution containing the ionic liquid and the manganese precursor; (2) preparing manganese difluoride (MnF ₂ ) by reacting the ionic liquid with the manganese precursor; And (3) manufacturing a negative electrode material comprising the manganese difluoride; is provided a method of manufacturing a negative electrode material for a lithium ion battery comprising a.

The reaction of step (2) may be performed by irradiating the mixed solution with microwaves.

The manganese difluoride may have a rod shape.

According to another aspect of the present invention, manganese difluoride (MnF ₂ ) prepared according to the manufacturing method of the manganese difluoride (MnF ₂ ) is provided.

The manufacturing method of manganese difluoride of the present invention can rapidly produce manganese difluoride having high crystallinity and a large specific surface area by using an ionic liquid and microwaves.

In addition, the manufacturing method of the anode material for a lithium ion battery of the present invention uses manganese difluoride prepared according to the manufacturing method of manganese difluoride as an anode material of a lithium ion battery, whereby the charge/discharge capacity and cycle characteristics of the lithium ion battery are improved. It works.

1 is a flowchart showing a method for manufacturing manganese difluoride according to the present invention.
2A is a graph showing microwave irradiation data of Examples 1-1 to 1-3, FIG. 2B is Examples 1-3 to 1-5, and FIG. 2C is Examples 1-6 to 1-8.
3a to 3j are SEM analysis images of each of manganese difluoride prepared according to Examples 1-1 to 1-10.
Figure 4a is an XRD analysis graph of manganese difluoride according to the concentration change, Figure 4b is an XRD analysis graph of manganese difluoride according to the microwave irradiation time, Figure 4c is an XRD analysis graph of manganese difluoride according to the temperature heated by the microwave , Figure 4d is an XRD analysis graph of manganese difluoride according to whether the manganese precursor is melted.
5 is an XRD analysis graph of manganese difluoride according to Examples 2-1 to 2-5.
6 is an XRD analysis graph of manganese difluoride according to Examples 3-1 to 3-5.
7 is an XRD graph of Mn (JCPDS card No. 21-0547), MnF ₂ P42m (JCPDS card No. 34-1356) and MnF ₂ P4 ₂ /mnm (JCPDS card No. 24-0727) for crystal structure comparison. to be.
8 is a graph showing the yield of manganese difluoride prepared according to Examples 2-1 to 2-5 and Examples 3-1 to 3-5.
9a to 9c are SEM analysis images of manganese difluoride according to Examples 2-1 to 2-3.
10a to 10d are SEM analysis images of manganese difluoride according to Examples 3-1 to 3-4.
11A is a charge/discharge curve of the lithium ion battery according to Device Example 1, and FIG. 11B is a graph showing cycle stability and efficiency of the lithium ion battery according to Device Example 1. FIG.
12a and 12b are adsorption isotherm graphs and BET plot graphs of manganese difluoride prepared according to Examples 1-10.

Since the present invention can apply various transformations and can have various embodiments, specific embodiments are illustrated and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. In describing the present invention, if it is determined that a detailed description of a related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted.

In addition, terms including ordinal numbers such as first, second, etc. to be used hereinafter may be used to describe various elements, but the elements are not limited by the terms. The above terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may also be referred to as a first component.

In addition, when it is mentioned that a component is “on another component,” “formed on another component,” “located on another component,” or “stacked on another component,” the It may be formed, positioned, or laminated by being directly attached to the front surface or one surface on the surface of other components, but it will be understood that other components may be further present in the middle.

The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present application, terms such as “comprise” or “have” are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It is to be understood that this does not preclude the possibility of the presence or addition of numbers, steps, operations, components, parts, or combinations thereof.

1 is a flowchart showing a method for manufacturing manganese difluoride according to the present invention. Hereinafter, a method for manufacturing manganese difluoride of the present invention will be described with reference to FIG. 1 .

First, an ionic liquid having a fluorine atom (F) and a manganese precursor are mixed to prepare a mixed solution containing the ionic liquid and a manganese precursor (step a).

The manganese precursor concentration of the mixed solution may be 0.01 to 2.5M, preferably 0.03 to 2M. When the concentration of the manganese precursor exceeds 2.5M, the size of the generated particles increases as the concentration increases, which is undesirable for manufacturing nanoparticles. Considering the amount of fluorine contained in the ionic liquid and manganese contained in the manganese precursor, The reaction may be difficult to occur. On the other hand, the manganese precursor concentration may vary depending on the type of the ionic liquid and the manganese precursor, and in the present invention, it can be applied when an ionic liquid containing BF ₄ and a manganese precursor containing one Mn per molecule are used. .

Step (a) comprises the steps of (a-1) melting the manganese precursor; and (a-2) mixing the molten manganese precursor with an ionic liquid having a fluorine atom (F) to prepare a mixed solution containing the ionic liquid and the manganese precursor; may include.

When the manganese precursor is melted and mixed with an ionic liquid as in step (a-1), a smaller size of mesh difluoride can be prepared.

The ionic liquid may be a compound represented by Structural Formula 1.

[Structural Formula 1]

In Structural Formula 1,

,

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, 또는

이고, X is

,

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ego,

R ₁ , R _{2 ,} R ₃ , and R ₄ are the same as or different from each other, and each independently represent a hydrogen atom, a C1 to C15 alkyl group, a C1 to C15 fluoroalkyl group, or a C2 to C15 alkenyl group. C6 to C16 aryl group, C7 to C16 arylalkyl group, or C7 to C16 alkylaryl group,

) 또는 헥사플루오로포스페이트(

)이다.Y is tetrafluoroborate (

) or hexafluorophosphate (

)to be.

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로 이루어진 군으로부터 선택된 1종 이상을 포함할 수 있다.In Structural Formula 1, X is

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and

It may include one or more selected from the group consisting of.

The ionic liquid is EMIM BF4 (1-Ethyl-3-methylimidazolium tetrafluoroborate), BMIM BF4 (1-Butyl-3-methylimidazolium tetrafluoroborate), and OMIM BF4 (1-Methyl-3-octyl-imidazolium-tetrafluoroborate) It may include one or more selected from.

The ionic liquid may be a source of fluorine (F, Fluorine) and a solvent absorbing microwaves.

The mixed solution may further include a compound represented by Structural Formula 2 below.

[Structural Formula 2]

in Structural Formula 2

R ₅ is a C1 to C6 alkylene group,

n is an integer from 1 to 1,000.

The compound represented by Structural Formula 2 may be ethylene glycol.

A volume ratio (A:B) of the ionic liquid (A) and the compound (B) represented by Structural Formula 2 in the mixed solution may be 10:90 to 50:50.

The manganese precursor may include a manganese salt, and the manganese salt is manganese nitrate (Manganese(II) nitrate, Mn(NO ₃ ) ₂ ), manganese acetate (Manganese(II) acetate, Mn(CH ₃ COO) ₂ ) , Manganese(II) sulfate, MnSO ₄ ), Manganese(II) chloride, MnCl2), Manganese(II) hydroxide, Mn(OH)2), Manganese(II) sulfide , MnS), manganese carbonate (Manganese(II) carbonate, MnCO ₃ ), manganese bromide (Manganese(II) bromide, MnBr ₂ ), manganese perchlorate (Manganese(II) Perchlorate, Mn(ClO ₄ ) ₂ ) and hydrates thereof It may include one or more selected from the group consisting of.

Next, by reacting the ionic liquid of the mixed solution with the manganese precursor, manganese difluoride (MnF ₂ ) is prepared (step b).

The reaction of step (b) may be performed by irradiating the mixed solution with microwaves.

The reaction of step (b) may be carried out at a temperature of 100 to 200 °C, preferably at 110 to 190 °C, more preferably at a temperature of 120 to 180 °C. In addition, the mixed solution may be heated to the above temperature range through microwave irradiation. When the reaction of step (b) is carried out at a temperature of less than 100 ° C, it is not preferable to a low temperature at which the reaction occurs, and when it is carried out at a temperature of more than 200 ° C, the reaction time is increased and the size of the particles is increased, so that the nanoparticles are prepared not desirable for

The power of the microwave may be 5 to 1800W, and the power of the microwave may vary greatly depending on the structure of the microwave equipment, the size of the microwave equipment, the amount of reactant, the volume of the solution, the volume of the equipment, etc. The power of the microwave can be selected according to the equipment and reaction conditions. In addition, the greater the power of the microwave, the faster the reaction temperature can be reached, thereby reducing the production time of manganese difluoride.

The microwave irradiation time may be 10 seconds to 3600 seconds, preferably 20 to 2400 seconds. If the irradiation time of the microwave is less than 10 seconds, it is not preferable because the time is too short for the reaction to occur, and if it is more than 3600 seconds, it is not suitable for the purpose of rapid production, and the size of the particles may be increased. Meanwhile, the irradiation time of the microwave may be adjusted according to the power of the microwave. In addition, the microwave irradiation time becomes longer as the target reaction temperature increases, and becomes shorter as the microwave power increases.

The manganese difluoride (MnF ₂ ) may have a rod shape.

The manufacturing method of the manganese difluoride (MnF ₂ ) uses microwaves as an energy source to react manganese in the decomposed manganese precursor with fluorine in an ionic liquid to produce manganese difluoride (MnF ₂ ), which is an ionic liquid. The size (tens of nanometers to several um) and shape of the product (manganese difluoride) are determined by the concentration of the manganese precursor, microwave power, irradiation time and temperature, and the purity of the ionic liquid. The larger the concentration of the manganese precursor in the solvent (ionic liquid), the greater the microwave power, and the longer the microwave irradiation time, the larger the product (manganese difluoride).

In addition, the present invention provides a manganese difluoride (MnF ₂ ) prepared according to the manufacturing method of the manganese difluoride (MnF ₂ ).

In addition, the present invention comprises the steps of (1) mixing an ionic liquid having a fluorine atom (F) and a manganese precursor to obtain a mixed solution containing the ionic liquid and a manganese precursor; (2) preparing manganese difluoride (MnF ₂ ) by reacting the ionic liquid with the manganese precursor; and (3) preparing a negative electrode material comprising the manganese difluoride;

The reaction of step (2) may be performed by irradiating the mixed solution with microwaves.

The manganese difluoride may have a rod shape.

[Example]

Hereinafter, the present invention will be described in more detail by way of examples. However, this is for illustrative purposes and the scope of the present invention is not limited thereby.

Example 1: BMIM BF ₄ Manganese difluoride (MnF) using ₂ ) manufacturing

Example 1-1

Mix 5 mL of ionic liquid BMIM BF ₄ (1-Butyl-3-methylimidazolium tetrafluoroborate) with manganese precursor manganese nitrate tetrahydrate (Manganese(II) nitrate tetrahydrate, Mn(NO ₃ ) ₂ 4H ₂ O, solid) and stirred to prepare a mixed solution. At this time, the concentration of the manganese precursor contained in the mixed solution was 0.05M.

Next, the mixed solution was heated to 180° C. while irradiating the mixed solution with microwaves for 5 minutes, and further irradiated with microwaves for 30 minutes while maintaining the heated temperature to prepare manganese difluoride (MnF ₂ ), centrifugal It was washed using a separator and dried before use.

Examples 1-2 to 1-8

Manganese difluoride (MnF ₂ ) in the same manner as in Example 1-1 by varying the concentration of the ionic liquid and the manganese precursor in Example 1-1, the microwave irradiation time, the microwave heating temperature, and whether the manganese precursor is melted. was prepared.

Examples 1-9

Instead of using the manganese precursor manganese nitrate tetrahydrate (Manganese(II) nitrate tetrahydrate, Mn(NO ₃ ) ₂ .4H ₂ O, solid) in Examples 1-8, the manganese precursor manganese nitrate tetrahydrate (Manganese(II) nitrate) Manganese difluoride (MnF ₂ ) in the same manner as in Example 1-8, except that tetrahydrate, Mn(NO ₃ ) ₂ .4H ₂ O, solid) was heated on a 40° C. hot plate and melted in a liquid state. was prepared.

Examples 1-10

In Examples 1-9, instead of using iolitec's BMIM BF ₄ (1-Butyl-3-methylimidazolium tetrafluoroborate) that is 99% pure in Examples 1-9, Sigma Aldrich's BMIM BF ₄ (1-Butyl-3-methylimidazolium tetrafluoroborate) with 98% purity Manganese difluoride (MnF ₂ ) was prepared in the same manner as in Examples 1-9, except that

Table 1 below describes the manufacturing conditions of Examples 1-1 to 1-10, respectively. At this time, the microwave irradiation data of Examples 1-1 to 1-3 through FIG. 2A, the microwave irradiation data of Examples 1-3 to 1-5 through FIG. 2B, and Examples 1-6 through FIG. 2C to 1-8 microwave irradiation data can be confirmed.

ionic liquid mixed concentration microwave power microwave irradiation time microwave heating temperature Whether the manganese precursor is melted Example 1-1 BM BF ₄
(99% purity, iolitec) 0.05M 0-180W
variable power 35 minutes
(5 min + 30 min) 180℃ × Example 1-2 BM BF ₄
(99% purity, iolitec) 0.5M 0-180W
variable power 35 minutes
(5 min + 30 min) 180℃ × Examples 1-3 BM BF ₄
(99% purity, iolitec) 1M 0-180W
variable power 35 minutes
(5 min + 30 min) 180℃ × Examples 1-4 BM BF ₄
(99% purity, iolitec) 1M 0-180W
variable power 5 minutes 180℃ × Examples 1-5 BM BF ₄
(99% purity, iolitec) 1M 0-180W
variable power 10 minutes
(5 min + 5 min) 180℃ × Examples 1-6 BM BF ₄
(99% purity, iolitec) 0.05M 500W 30 seconds 120℃ × Examples 1-7 BM BF ₄
(99% purity, iolitec) 0.05M 500W 35 seconds 150℃ × Examples 1-8 BM BF ₄
(99% purity, iolitec) 0.05M 500W 45 seconds 180℃ × Examples 1-9 BM BF ₄
(99% purity, iolitec) 0.05M 500 W 45 seconds 180℃ ○ Examples 1-10 BM BF ₄
(98% pure, Sigma Aldrich) 0.05M 500 W 45 seconds 180℃ ○

Example 2: EMIM BF ₄ Manganese difluoride (MnF) using ₂ ) manufacturing

Example 2-1

An ionic liquid EMIM BF ₄ (1-Ethyl-3-methylimidazolium tetrafluoroborate) was mixed with ethylene glycol to prepare a mixed solvent. At this time, the mixing volume ratio of the ionic liquid and the ethylene glycol is 0.2, and the mixing volume ratio is calculated using (volume of ionic liquid)/(volume of mixed solvent (ionic liquid + ethylene glycol)) can

Then, 5 mL of the mixed solvent and manganese acetate tetrahydrate (Manganese(II) acetate tetrahydrate, Mn(CH ₃ COO) ₂ .4H ₂ O) were mixed and stirred to prepare a mixed solution. At this time, the concentration of the manganese precursor contained in the mixed solution was 0.05M.

Next, the mixed solution was heated to 180° C. while irradiating a microwave (500 W) for 55 seconds to prepare manganese difluoride (MnF ₂ ), washed using a centrifuge, and dried.

Examples 2-2 to 2-5

Manganese difluoride (MnF ₂ ) was prepared in the same manner as in Example 2-1 by varying the mixing volume ratio of the ionic liquid and ethylene glycol in Example 2-1.

The manufacturing conditions of Examples 2-1 to 2-5 are described in Table 2 below, respectively.

ionic liquid mixed volume ratio mixed concentration microwave power microwave irradiation time microwave heating temperature Whether the manganese precursor is melted Example 2-1 EMIM BF ₄ 0.2 0.05M 500W 55 seconds 180℃ × Example 2-2 EMIM BF ₄ 0.4 0.5M 500W 55 seconds 180℃ × Example 2-3 EMIM BF ₄ 0.6 1M 500W 55 seconds 180℃ × Example 2-4 EMIM BF ₄ 0.8 1M 500W 45 seconds 180℃ × Example 2-5 EMIM BF ₄ One 1M 500W 50 seconds 180℃ ×

Example 3: OMIM BF ₄ Manganese difluoride (MnF) using ₂ ) manufacturing

Example 3-1

Except for using the ionic liquid OMIM BF4 (1-Methyl-3-octyl-imidazolium-tetrafluoroborate) in Example 2-1 instead of using the ionic liquid EMIM BF ₄ (1-Ethyl-3-methylimidazolium tetrafluoroborate) Then, manganese difluoride (MnF ₂ ) was prepared in the same manner as in Example 2-1.

Examples 3-2 to 3-5

Manganese difluoride (MnF ₂ ) was prepared in the same manner as in Example 3-1 by varying the mixing volume ratio of the ionic liquid and ethylene glycol in Example 3-1.

The manufacturing conditions of Examples 3-1 to 3-5 are described in Table 3 below, respectively.

ionic liquid mixed volume ratio mixed concentration microwave power microwave irradiation time microwave heating temperature Whether the manganese precursor is melted Example 2-1 OMIM BF ₄ 0.2 0.05M 500W 40 seconds 180℃ × Example 1-2 OMIM BF ₄ 0.4 0.5M 500W 50 seconds 180℃ × Examples 1-3 OMIM BF ₄ 0.6 1M 500W 50 seconds 180℃ × Examples 1-4 OMIM BF ₄ 0.8 1M 500W 50 seconds 180℃ × Examples 1-5 OMIM BF ₄ One 1M 500W 40 seconds 180℃ ×

Device Example 1: Preparation of coin-type half-cell

Manganese difluoride (MnF ₂ ) prepared according to Examples 1-10 was used as a negative electrode active material, acetylene black as a conductive material, and polyvinylidene fluoride (PVDF) as a binder, the negative electrode active material, conductive material and binder were used. A mixed solution was prepared by mixing in a weight ratio of 5:3:2, and N-methyl-2-pyrrolidone as a solvent was mixed with the mixed solution to prepare a slurry. The slurry was coated on one surface of a copper current collector to a thickness of 30 μm, dried and rolled, and then punched to a predetermined size to prepare a negative electrode. In addition, an organic solvent containing 1.0M LiPF ₆ and mixed with ethylene carbonate and diethyl carbonate in a volume ratio of 1:1 was used as a non-aqueous electrolyte, and a lithium metal foil was used as a counter electrode. , a polymer membrane mixed with glass fiber separator was interposed between both electrodes, and then the non-aqueous electrolyte was injected to prepare a coin-type half-cell.

Device Example 2: Preparation of coin-type half-cell

In Device Example 1, instead of using the manganese difluoride (MnF ₂ ) prepared according to Examples 1-10 as the negative electrode active material, the manganese difluoride (MnF ₂ ) prepared according to Examples 1-5 was used as the negative electrode active material. A coin-type half-cell was manufactured in the same manner as in Device Example 1, except that

[Test Example]

Test Example 1: Ionic liquid (BMIM BF ₄ ) SEM and XRD analysis of examples using

3a to 3j are SEM analysis images of each of manganese difluoride prepared according to Examples 1-1 to 1-10, FIG. 4a is an XRD analysis graph of manganese difluoride according to concentration change, and FIG. 4b is microwave irradiation time. An XRD analysis graph of manganese difluoride according to , FIG. 4c is an XRD analysis graph of manganese difluoride according to a temperature heated by microwaves, and FIG. 4d is an XRD analysis graph of manganese difluoride according to whether a manganese precursor is melted. As the manufacturing conditions of manganese difluoride were changed, changes in the product manganese difluoride were observed.

SEM and XRD analysis of products with varying concentrations

According to FIGS. 3A to 3C and 4A , it was confirmed that the manganese difluoride particles were formed to be larger as the concentration increased.

SEM and XRD analysis of products according to microwave irradiation time

According to FIGS. 3C to 3E and 4B , it was confirmed that the size of the manganese difluoride particles increased as the microwave irradiation time increased.

SEM and XRD analysis of products as a function of temperature heated by microwaves

According to FIGS. 3f to 3h and 4c, it can be seen that the manganese difluoride nanoparticles are formed at a temperature of 120° C. or higher, and the lower the temperature, the shorter the time. In addition, the crystalline size calculated through the Scherrer equation based on the result of FIG. 4c is 17.19 nm in the case of Examples 1-6 (FIG. 3F), 18.47 nm in the case of Examples 1-7 (FIG. 3G), and Examples 1-8 ( In the case of FIG. 3h), it was shown to be 20.98 nm, indicating that the higher the temperature heated by the microwave, the longer the reaction time and the larger the particle size.

In addition, when microwaves were irradiated with a power of 500W, the time to reach 120°C was 30 seconds, and it was confirmed that manganese difluoride particles having a size of several tens of nanometers could be produced only by a reaction of 30 seconds.

SEM and XRD analysis of the product depending on whether the manganese precursor is melted or not

According to FIGS. 3H to 3I, it was found that in the case of Examples 1-9 (FIG. 3I), smaller particles were generated than in Examples 1-8 (FIG. 3H), which was not performed due to the melting and reaction of the manganese precursor.

In addition, according to FIG. 4D, in the case of Examples 1-9, in which manganese difluoride was prepared by melting a manganese precursor, the XRD peak was clearer at around 50-60 degrees, so the crystallinity of manganese difluoride in which the manganese precursor was melted and reacted I found this to be even better.

In addition, the melting point of manganese nitrate tetrahydrate used as a manganese precursor was 37° C., compared to Examples 1-8 in which manganese difluoride was prepared by mixing manganese nitrate tetrahydrate in a solid state with an ionic liquid, The manganese difluoride yield of Examples 1-9, in which manganese difluoride was prepared by heating manganese nitrate tetrahydrate on a hot plate at 40° C. and mixing it with an ionic liquid in a liquid state, was increased by 1.8 times. Specifically, in the case of the molten Example 1-9, the amount of the product was 0.0520 g based on 15 ml of the ionic liquid, and in the case of the non-melting Example 1-8, 0.0286 g.

SEM analysis of the product according to the purity of the ionic liquid

According to FIGS. 3i and 3j, unlike the manganese difluoride of Examples 1-9 prepared using BMIM BF ₄ of iolitec of 99% purity, manganese difluoride prepared using BMIM BF ₄ of Sigma-Aldrich of 98% purity It was confirmed that the silver was formed into rod-like nanostructures.

Test Example 2: Ionic liquid (EMIM BF ₄ and OMIM BF ₄ ) SEM and XRD analysis of examples using

5 is an XRD analysis graph of manganese difluoride according to Examples 2-1 to 2-5, FIG. 6 is an XRD analysis graph of manganese difluoride according to Examples 3-1 to 3-5, and FIG. 7 is a crystal structure XRD graphs of Mn (JCPDS card No. 21-0547), MnF ₂ P42m (JCPDS card No. 34-1356) and MnF ₂ P4 ₂ /mnm (JCPDS card No. 24-0727) for comparison. Also, FIGS. 9A to 9C are SEM analysis images of manganese difluoride according to Examples 2-1 to 2-3, and FIGS. 10A to 10D are SEM analysis images of manganese difluoride according to Examples 3-1 to 3-4.

5 and 9a to 9c, it was found that the crystal structure and shape of the produced manganese difluoride changed according to the mixing ratio of the ionic liquid EMIMBF ₄ and ethylene glycol. When the mixing ratio is 0.2 (Example 2-1) and 0.4 (Example 2-2), when manganese difluoride having a P4 ₂ /mnm crystal structure is generated, their shape is as shown in FIGS. 8a and 8b. Fine nanoparticles are agglomerated It has a circular shape of 100-300 nm nano-aggregates. In addition, when the mixing ratio is 0.6 (Example 2-3), manganese difluoride having a crystal structure of P42m is produced, and the form appears in the form of non-uniform nanoparticles unlike the case where the mixing ratio is 0.2 and 0.4, which is a difference in crystal structure. is due to In the case of a mixing ratio of 0.8 (Example 2-4), manganese difluoride having two crystal structures of P4 ₂ /mnm and P42m is, and when the mixing ratio is 1 (Example 2-5), manganese difluoride having a crystal structure of P4 ₂ /mnm It is produced by mixing manganese and

In addition, according to FIGS. 6 and 10a to 10d, when OMIMBF ₄ is used as the ionic liquid, manganese difluoride having a P4 ₂ /mnm crystal structure is produced regardless of the mixing ratio of ethylene glycol, and it can be seen that all are produced in the form of nanoparticles. .

Therefore, it was possible to control the crystal structure of manganese difluoride and the particle size and shape of manganese difluoride according to the type of ionic liquid and the mixing volume ratio of ethylene glycol.

Test Example 3: Ionic liquid (EMIM BF) ₄ and OMIM BF ₄ ) yield analysis of examples using

8 is a graph showing the yield of manganese difluoride prepared according to Examples 2-1 to 2-5 and Examples 3-1 to 3-5.

According to FIG. 8, it was found that the production amount of manganese difluoride could be increased through the mixing of ethylene glycol and the ionic liquid. Therefore, it was possible to control the yield of manganese difluoride according to the type of ionic liquid and the mixing volume ratio of ethylene glycol.

Test Example 4: Performance evaluation of coin-type lithium half-cell

11A is a charge/discharge curve of the coin-type lithium half battery according to Device Example 1, and FIG. 11B is a graph showing the efficiency of the coin-type lithium half battery according to Device Example 1. FIG. 11c is a charge/discharge curve of a coin-type lithium half-cell according to Device Example 2, and FIG. 11d is a graph showing the efficiency of a coin-type lithium half-cell according to Device Example 2.

11A to 11D, the charge/discharge capacity of Device Example 1 was approximately 1000 mAh/g, which was twice higher than that of Device Example 2 of 460 mAh/g. In addition, both the batteries according to Device Example 1 and Device Example 2 showed a higher value than the charge/discharge capacity 372 mAh/g of the battery using a commercially used graphite anode material. This seems to be because the manganese difluoride prepared by using an ionic liquid and microwaves has high crystallinity, and in particular, the specific surface area of manganese difluoride according to Examples 1-10 is large.

Test Example 5: Analysis of specific surface area

12A and 12B are adsorption isotherm graphs and BET plot graphs of manganese difluoride prepared according to Examples 1-10 measured using BET equipment.

12A and 12B, it can be calculated that the specific surface area of Examples 1-10 is 65.848 [m ² /g]. This supports that the high charge/discharge capacity of Device Example 1 is due to the high specific surface area of the nanostructures of Examples 1-10. Compared with the literature value reported for reference, manganese difluoride in the literature has a specific surface area of 12.3 [m ² /g] and a charge capacity of approximately 500 mAh/g.

In the above, although preferred embodiments of the present invention have been described, those of ordinary skill in the art can add, change, delete or The present invention may be variously modified and changed by addition and the like, and this will also be included within the scope of the present invention. For example, each component described as a single type may be implemented in a dispersed form, and likewise components described as distributed may be implemented in a combined form. The scope of the present invention is indicated by the following claims rather than the above detailed description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be interpreted as being included in the scope of the present invention. do.

Claims (19)

(a-1) melting the manganese precursor;
(a-2) mixing the molten manganese precursor with an ionic liquid having a fluorine atom (F) to prepare a mixed solution containing the ionic liquid and the manganese precursor; and
(b) preparing manganese difluoride (MnF ₂ ) by reacting the ionic liquid with the manganese precursor; including,
The reaction of step (b) will be carried out by irradiating the microwave to the mixed solution, manganese difluoride (MnF ₂ ) Method for producing. delete According to claim 1,
Method for producing manganese difluoride, characterized in that the reaction of step (b) is carried out at a temperature of 100 to 200 ℃. According to claim 1,
Method for producing manganese difluoride, characterized in that the microwave irradiation time is 10 seconds to 3600 seconds. According to claim 1,
The method for producing manganese difluoride, characterized in that the concentration of the manganese precursor in the mixed solution is 0.01 to 2.5M. According to claim 1,
The manufacturing method of manganese difluoride, characterized in that the manganese difluoride is in the shape of a rod (rod). delete According to claim 1,
Method for producing manganese difluoride, characterized in that the ionic liquid is a compound represented by Structural Formula 1.
[Structural Formula 1]

In Structural Formula 1,
X is

,

,

,

,

, or

ego,
R ₁ , R _{2 ,} R ₃ , and R ₄ are the same as or different from each other, and each independently represent a hydrogen atom, a C1 to C15 alkyl group, a C1 to C15 fluoroalkyl group, or a C2 to C15 alkenyl group. C6 to C16 aryl group, C7 to C16 arylalkyl group, or C7 to C16 alkylaryl group,
Y is tetrafluoroborate (

) or hexafluorophosphate (

)to be. 9. The method of claim 8,
wherein X is

,

,

.

,

,

,

,

,

,

,

,

,

,

,

,

,

,

,

,

,

,

,

,

,

,

,

,

.

,

,

,

and

Manganese difluoride manufacturing method comprising at least one selected from the group consisting of. According to claim 1,
The ionic liquid is EMIM BF4 (1-Ethyl-3-methylimidazolium tetrafluoroborate), BMIM BF4 (1-Butyl-3-methylimidazolium tetrafluoroborate), and OMIM BF4 (1-Methyl-3-octyl-imidazolium-tetrafluoroborate) A method for manufacturing manganese difluoride, comprising at least one selected from According to claim 1,
The method for producing manganese difluoride, characterized in that the mixed solution further comprises a compound represented by the following structural formula (2).
[Structural Formula 2]

in Structural Formula 2
R ₅ is a C1 to C6 alkylene group,
n is an integer from 1 to 1,000. 12. The method of claim 11,
A method for producing manganese difluoride, characterized in that the compound represented by Structural Formula 2 is ethylene glycol. 13. The method of claim 12,
A method for producing manganese difluoride, characterized in that the volume ratio (A:B) of the ionic liquid (A) and the compound (B) represented by Structural Formula 2 in the mixed solution is 10:90 to 50:50. According to claim 1,
The manganese precursor is a method for producing manganese difluoride, characterized in that it comprises a manganese salt. 15. The method of claim 14,
The manganese salt is manganese nitrate (Manganese(II) nitrate, Mn(NO ₃ ) ₂ ), manganese acetate (Manganese(II) acetate, Mn(CH ₃ COO) ₂ ), manganese sulfate (Manganese(II) sulfate, MnSO ₄ ) ), Manganese(II) chloride, MnCl2), Manganese(II) hydroxide, Mn(OH)2), Manganese(II) sulfide, MnS), Manganese(II) carbonate , MnCO ₃ ), manganese bromide (Manganese(II) bromide, MnBr ₂ ), manganese perchlorate (Manganese(II) Perchlorate, Mn(ClO ₄ ) ₂ ) and a quilt comprising at least one selected from the group consisting of hydrates thereof A method for producing manganese. (1-1) melting the manganese precursor;
(1-2) preparing a mixed solution containing the ionic liquid and the manganese precursor by mixing the molten manganese precursor with an ionic liquid having a fluorine atom (F); and
(2) preparing manganese difluoride (MnF ₂ ) by reacting the ionic liquid with the manganese precursor; and
(3) preparing a negative electrode material containing the manganese difluoride;
The method of manufacturing a negative electrode material for a lithium ion battery, wherein the reaction of step (2) is performed by irradiating the mixed solution with microwaves. delete 17. The method of claim 16,
The method of manufacturing a negative electrode material, characterized in that the manganese difluoride is in the shape of a rod. Manganese difluoride prepared by the manufacturing method according to claim 1 (MnF ₂ ).

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