KR102578412B1 - Electrolyte composition for indium plating of lithium electrode anc manufacturing method of lithium metal anode using the same - Google Patents

Abstract

The present invention relates to an electrolyte composition for indium plating of a lithium electrode and a method of manufacturing a lithium metal anode using the same. One aspect of the invention is a lithium salt; Organic solvents, including a glyme-based solvent or a mixed solvent of a glyme-based solvent and a fluorine-based solvent; and an additive containing indium ions (In ³⁺ ). An electrolyte composition for indium plating of a lithium electrode is provided.

Description

Electrolyte composition for indium plating of lithium electrode and method of manufacturing lithium metal anode using same {ELECTROLYTE COMPOSITION FOR INDIUM PLATING OF LITHIUM ELECTRODE ANC MANUFACTURING METHOD OF LITHIUM METAL ANODE USING THE SAME}

The present invention relates to an electrolyte composition for indium plating of lithium electrodes and a method of manufacturing a lithium metal anode using the same.

The lithium secondary battery using a lithium metal negative electrode is the first reusable lithium secondary battery attempted. Lithium metal with high capacity per unit weight (3,860 mAhg ^-1 ) and low reduction potential (-3.040 V vs. standard hydrogen electrode) is used as the negative electrode. Use it as

Lithium secondary batteries using lithium metal negative electrodes have the advantage of being able to have high energy density when the amount of negative electrode is minimized, but cell performance continues to decrease due to lithium dendrites formed on the surface of the negative electrode during the charging and discharging process, and the dendrites continue to form. Due to the disadvantage that safety problems may arise due to growth, its use was discontinued after the development of a stable carbon-based cathode to replace it.

However, problems caused by the low capacity of carbon-based materials and the high volume expansion rate of non-carbon-based anodes such as silicon used subsequently created difficulties in meeting the level required by the mid- to large-sized lithium secondary battery market.

Accordingly, re-research on lithium metal anodes with high energy density is currently underway.

However, in order to improve the performance and commercialize lithium secondary batteries using lithium metal negative electrodes, the electrochemical instability of lithium metal must be resolved, and in particular, there is a need to suppress the growth of dendritic lithium formed on the surface of lithium metal.

Therefore, there is a need to develop a stable protective film layer formation technology that can physically inhibit the growth of dendritic lithium on the surface of lithium metal or increase the stability of the interface to inhibit the formation of dendritic lithium itself.

The above-mentioned background technology is possessed or acquired by the inventor in the process of deriving the disclosure of the present application, and cannot necessarily be said to be known technology disclosed to the general public before the present application.

The present invention is to solve the above-mentioned problems, and the purpose of the present invention is to form a technology for forming an indium-lithium alloy protective film layer that can improve the performance of a lithium metal electrode battery by suppressing lithium dendrites occurring on the surface of a lithium metal negative electrode. is to provide.

That is, the purpose of the present invention is to provide an electrolyte composition for indium plating of a lithium electrode and a method of manufacturing a lithium metal anode with a protective film layer formed using the same.

Another object of the present invention is to provide a lithium secondary battery including a lithium metal negative electrode on which a protective film layer is formed.

However, the problems to be solved by the present invention are not limited to those mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

One aspect of the present invention is a lithium salt; Organic solvents, including a glyme-based solvent or a mixed solvent of a glyme-based solvent and a fluorine-based solvent; and an additive containing indium ions (In ³⁺ ). An electrolyte composition for indium plating of a lithium electrode is provided.

According to one embodiment, the additive containing the indium ion is indium nitrate (In(NO ₃ ) ₃ ), indium bis(trifluoromethanesulfonyl)imide (In(TFSI) ₃ ), and indium fluoride. It may include one or more selected from the group consisting of (InF ₃ ).

According to one embodiment, the additive containing the indium ion may be included in an amount of 0.5% by weight to 2% by weight.

According to one embodiment, the lithium salt is LiFSI, LiTFSI, LiBF ₄ , LiBOB, LiPF ₆ , LiFOB, LiClO ₄ , LiSO ₃ CF ₃ , LiDFBP, LiTFOP, LiPO ₂ F ₂ , LiCl, LiBr, LiI, LiB ₁₀ Cl ₁₀ , LiCF ₃ SO ₃ , LiCF ₃ CO ₂ , LiAsF ₆ , LiSbF ₆ , LiAlCl ₄ , CH ₃ SO ₃ Li, CF ₃ SO ₃ Li, LiSCN, and LiC(CF ₃ SO ₂ ) ₃ selected from the group consisting of It may contain more than one.

According to one embodiment, the concentration of the lithium salt may be 1 M to 5 M.

According to one embodiment, the glyme-based solvent includes at least one selected from the group consisting of dimethyl ether, 1,3-dioxolane, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, and tetraethylene glycol dimethyl ether. It may be.

According to one embodiment, the fluorine-based solvent is fluoroethylene carbonate (FEC), difluoroethylene carbonate (DFEC), 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetra fluorine Ropropyl ether, 1,1,2,2-tetrafluoro ethyl-1H,1H,5H-octafluoropentyl ether and 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoro. It may include one or more selected from the group consisting of loethyl ether.

According to one embodiment, the volume ratio of the glyme-based solvent and the fluorine-based solvent may be 10:1 to 1:1.

Another aspect of the present invention is a lithium metal anode; Indium metal anode; and an electrolyte solution containing the electrolyte composition for indium plating; manufacturing an indium-lithium battery including a; and applying a current to the indium-lithium battery to form an indium-lithium alloy layer on the surface of the lithium metal anode.

According to one embodiment, a film layer containing LiF may be simultaneously formed on the surface of the lithium metal anode.

Another aspect of the present invention is a lithium metal anode having a protective film layer formed on the surface of the lithium metal; anode; electrolyte; and a separator, wherein the protective film layer includes an indium-lithium alloy layer and a film layer containing LIF.

According to one embodiment, the thickness of the protective film layer may be 2 ㎛ to 8 ㎛.

According to one embodiment, the electrolyte solution includes lithium salt; and a glyme-based organic solvent.

According to one embodiment, the ratio of the indium-lithium alloy layer and the coating layer containing the LIF may be 1:1 to 5:1.

According to one embodiment, the electrolyte solution includes a functional additive including lithium difluoro bis(oxalato)phosphate (LiDFBP) and lithium nitrate (LiNO ₃ ). Additionally, the functional additive may be included in an amount of 1% to 10% by weight in the electrolyte solution.

The electrolyte composition for indium plating of a lithium electrode according to the present invention includes a functional additive containing indium ions (In ³⁺ ), thereby forming an indium-lithium alloy layer on the surface of the lithium metal electrode for a lithium secondary battery, thereby forming a protective film layer. It has the effect of producing a lithium metal anode. Additionally, by including a fluorine-based solvent, there is an effect of forming a LiF film on the surface of a lithium metal electrode for a lithium secondary battery.

The lithium metal negative electrode for a lithium secondary battery according to the present invention includes an indium-lithium alloy layer on the surface, thereby improving the reversibility of the electrodeposition and desorption reaction of lithium and suppressing side reactions with the electrolyte, thereby improving the performance of the lithium secondary battery. There is an effect.

Figure 1 is a schematic diagram showing a method for manufacturing a lithium negative electrode plated with an indium-lithium alloy layer and a method for evaluating the reversibility of a battery manufactured using the same according to an embodiment of the present invention.
Figure 2 shows the HOMO/LUMO energy of each component included in the electrolyte composition for indium plating according to an embodiment of the present invention.
Figure 3 shows the reduction decomposition evaluation according to the application of indium additive.
Figure 4 shows SEM images and EDS analysis results for the plated indium-lithium alloy layer.
Figure 5 shows the results of reversibility evaluation of a lithium metal anode according to an embodiment of the present invention.

Hereinafter, embodiments will be described in detail with reference to the attached drawings. However, various changes can be made to the embodiments, so the scope of the patent application is not limited or limited by these embodiments. It should be understood that all changes, equivalents, or substitutes for the embodiments are included in the scope of rights.

The terms used in the examples are for descriptive purposes only and should not be construed as limiting. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, terms such as “comprise” or “have” are intended to designate the presence of features, numbers, steps, operations, components, parts, or combinations thereof described in the specification, but are not intended to indicate the presence of one or more other features. It should be understood that this does not exclude in advance the possibility of the existence or addition of elements, numbers, steps, operations, components, parts, or combinations thereof.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by a person of ordinary skill in the technical field to which the embodiments belong. Terms defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and unless explicitly defined in the present application, should not be interpreted in an ideal or excessively formal sense. No.

In addition, when describing with reference to the accompanying drawings, identical components will be assigned the same reference numerals regardless of the reference numerals, and overlapping descriptions thereof will be omitted. In describing the embodiments, if it is determined that detailed descriptions of related known technologies may unnecessarily obscure the gist of the embodiments, the detailed descriptions are omitted.

Additionally, in describing the components of the embodiment, terms such as first, second, A, B, (a), and (b) may be used. These terms are only used to distinguish the component from other components, and the nature, sequence, or order of the component is not limited by the term. When a component is described as being "connected," "coupled," or "connected" to another component, that component may be directly connected or connected to that other component, but there is no need for another component between each component. It should be understood that may be “connected,” “combined,” or “connected.”

Components included in one embodiment and components including common functions will be described using the same names in other embodiments. Unless stated to the contrary, the description given in one embodiment may be applied to other embodiments, and detailed description will be omitted to the extent of overlap.

One aspect of the present invention is a lithium salt; Organic solvents, including a glyme-based solvent or a mixed solvent of a glyme-based solvent and a fluorine-based solvent; and an additive containing indium ions (In ³⁺ ). An electrolyte composition for indium plating of a lithium electrode is provided.

The electrolyte composition for indium plating according to the present invention includes a functional additive containing indium ions with lithium-friendly properties, thereby forming an indium-lithium alloy protective film layer with both physical and electrochemical stability on the lithium electrode interface. There is a characteristic.

A lithium electrode with an indium-lithium alloy layer formed on its surface has the effect of increasing the reversibility of lithium electrodeposition and desorption reactions and suppressing lithium dendrites.

According to one embodiment, the additive containing the indium ion is indium nitrate (In(NO ₃ ) ₃ ), indium bis(trifluoromethanesulfonyl)imide (In(TFSI) ₃ ), and indium fluoride. It may include one or more selected from the group consisting of (InF ₃ ).

The additive containing indium ions may have the lowest LUMO energy level among the components included in the electrolyte composition for indium plating.

Therefore, it is reduced on the surface of the lithium metal anode before other components, and through this, a lithium-indium alloy layer, that is, a protective film layer, can be formed.

The indium-lithium-containing layer lowers the energy barrier on the surface of lithium metal, thereby increasing the reversibility of lithium metal during the electrodeposition and desorption process of lithium, and physically disconnecting the electrochemically unstable lithium metal cathode from the electrolyte solution. Protects the lithium metal cathode from side reactions.

According to one embodiment, the additive containing the indium ion may be included in an amount of 0.5% by weight to 2% by weight.

Preferably, it may be included in 0.5% by weight to 1.5% by weight, and more preferably, it may be included in 0.8% by weight to 1.2% by weight.

If the additive containing indium ions is contained below the above range, an indium-lithium alloy layer may not be sufficiently formed on the lithium metal anode.

On the other hand, when the additive containing the indium ion is included in excess of the above range, it is relatively difficult to form a LiF film layer, and the strength of the protective film layer may be reduced.

According to one embodiment, the lithium salt is LiFSI, LiTFSI, LiBF ₄ , LiBOB, LiPF ₆ , LiFOB, LiClO ₄ , LiSO ₃ CF ₃ , LiDFBP, LiTFOP, LiPO ₂ F ₂ , LiCl, LiBr, LiI, LiB ₁₀ Cl ₁₀ , LiCF ₃ SO ₃ , LiCF ₃ CO ₂ , LiAsF ₆ , LiSbF ₆ , LiAlCl ₄ , CH ₃ SO ₃ Li, CF ₃ SO ₃ Li, LiSCN, and LiC(CF ₃ SO ₂ ) ₃ selected from the group consisting of It may contain more than one.

According to one embodiment, the concentration of the lithium salt may be 1 M to 5 M.

Preferably, it may be 1 M to 3 M, more preferably, it may be 1.5 M to 3 M, and even more preferably, it may be 1.5 M to 2.5 M.

If the concentration of the lithium salt is less than the above range, the conductivity in the electrolyte composition for indium plating may be lowered, thereby reducing the plating speed, and the reversibility of lithium may be reduced due to decomposition of the organic solvent.

On the other hand, when the concentration of the lithium salt exceeds the above range, electrodeposition may be difficult due to poor wetting of the separator due to high viscosity. In addition, the frequency of contact of the indium additive in the electrolyte composition for indium plating with lithium ions increases compared to the frequency of contact with the surface of the lithium metal anode, resulting in less reduction of the indium additive on the surface of the lithium metal anode, which may result in insufficient plating.

According to one embodiment, the organic solvent may be included in an amount of 60% by weight to 99% by weight based on the total volume of the electrolyte composition for indium plating.

According to one embodiment, the glyme-based solvent includes at least one selected from the group consisting of dimethyl ether, 1,3-dioxolane, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, and tetraethylene glycol dimethyl ether. It may be.

The glyme-based solvent has a high dipole moment, which can improve lithium ion mobility and lithium salt dissociation, and has the effect of improving ion conductivity of the electrolyte composition for indium plating.

According to one embodiment, the glyme-based solvent may be included in an amount of 70% to 90% by volume based on the total volume of the electrolyte composition for indium plating.

According to one embodiment, the fluorine-based solvent is fluoroethylene carbonate (FEC), difluoroethylene carbonate (DFEC), 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetra fluorine Ropropyl ether, 1,1,2,2-tetrafluoro ethyl-1H,1H,5H-octafluoropentyl ether and 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoro. It may include one or more selected from the group consisting of loethyl ether.

The fluorine-based solvent is a fluorinated solvent, and forms a protective film layer together with the indium-lithium alloy layer by forming a LiF film layer on lithium metal.

The LiF film layer has high strength and has the characteristic of improving the reversibility of the lithium metal anode by physically suppressing the growth of lithium dendrites on the lithium metal surface.

According to one embodiment, the fluorine-based solvent may be included in an amount of 10% to 30% by volume based on the total volume of the electrolyte composition for indium plating.

According to one embodiment, the volume ratio of the glyme-based solvent and the fluorine-based solvent may be 10:1 to 1:1.

Preferably, it may be 8:1 to 1:1, more preferably, it may be 7:1 to 2:1, and even more preferably, it may be 5:1 to 3:1.

The volume ratio of the glyme-based solvent and the fluorine-based solvent may be in a range that maximizes the performance of the protective film layer by optimizing the ratio of the indium-lithium alloy layer and the LiF film layer formed on lithium metal.

The indium-lithium alloy layer has the characteristics of increasing the reversibility of the electrodeposition and desorption reaction of lithium on the surface of the lithium electrode, suppressing the formation of dendritic lithium, and suppressing side reactions with the electrolyte solution.

In addition, the LiF film layer is a high-strength film with high ion conductivity and suppresses the formation of dendritic lithium by allowing uniform lithium electrodeposition to occur.

Therefore, the performance of the protective film layer can be maximized by maximizing the synergy effect of the indium-lithium alloy layer and the LiF film layer.

The protective film layer suppresses side reactions between the lithium electrode and the electrolyte solution, increases the reversibility of lithium electrodeposition and desorption reactions, and inhibits the formation of dendritic lithium, thereby improving the performance and stability of the lithium metal secondary battery.

Here, the side reaction between the lithium electrode and the electrolyte may include an irreversible decomposition reaction of the electrolyte on the surface of the lithium electrode.

Another aspect of the present invention is a lithium metal anode; Indium metal anode; and an electrolyte solution containing the electrolyte composition for indium plating; manufacturing an indium-lithium battery including a; and applying a current to the indium-lithium battery to form an indium-lithium alloy layer on the surface of the lithium metal anode.

The method for manufacturing a lithium metal negative electrode for a lithium secondary battery according to the present invention can produce a lithium metal negative electrode with an indium-lithium alloy layer formed by electrodepositing indium on a lithium metal negative electrode using an electrolyte solution containing an electrolyte composition for indium plating. It works.

According to one embodiment, a film layer containing LiF may be simultaneously formed on the surface of the lithium metal anode.

That is, the lithium metal anode manufactured by the above manufacturing method has an indium-lithium alloy layer and a film layer containing LiF simultaneously formed on the surface to form a protective film layer, thereby increasing the reversibility of the electrodeposition and desorption reaction of lithium and forming a lithium dendrite layer. Its growth is suppressed and it is protected from the electrolyte solution, thereby improving the performance of lithium secondary batteries.

Another aspect of the present invention is a lithium metal anode having a protective film layer formed on the surface of the lithium metal; anode; electrolyte; and a separator, wherein the protective film layer includes an indium-lithium alloy layer and a film layer containing LIF.

The lithium secondary battery according to the present invention has improved performance based on the improved reversibility of the electrodeposition and desorption reaction of lithium in the lithium metal anode and the effect of inhibiting the growth of lithium dendrites occurring during repeated charging and discharging.

The indium-lithium alloy layer has the effect of increasing the reversibility of the electrodeposition and desorption reaction of lithium on the surface of the lithium metal anode, physically inhibiting the growth of lithium dendrites, and suppressing side reactions between the lithium metal anode and the electrolyte solution. have

The LiF film layer has high strength, physically inhibits the growth of lithium dendrites on the surface of the lithium electrode, and improves the reversibility of the lithium metal anode. In addition, it has the effect of suppressing salt decomposition in the lithium secondary battery electrolyte solution.

According to one embodiment, the thickness of the protective film layer may be 2 ㎛ to 8 ㎛.

Preferably, the thickness of the protective film layer may be 2 ㎛ to 6 ㎛, more preferably 3 ㎛ to 6 ㎛, and even more preferably 3 ㎛ to 5 ㎛.

If the thickness of the protective film layer is less than the above range, the effect of inhibiting lithium dendritic growth and side reactions with the electrolyte may be reduced, and if it exceeds the above range, it may act as a resistance layer and reduce cell performance. .

According to one embodiment, the positive electrode may be used as a positive electrode active material of a lithium secondary battery including a lithium metal negative electrode without limitation. For example, the anode may contain copper.

According to one embodiment, the electrolyte solution includes lithium salt; and a glyme-based organic solvent.

According to one embodiment, the electrolyte solution is additive-free, and the additive may form a film on the surface of lithium metal.

That is, the lithium secondary battery according to the present invention uses a lithium metal negative electrode with a protective film layer formed on the lithium metal, thereby improving the interfacial stability of the lithium negative electrode without separately using a functional additive that generally forms a film layer on the surface of the lithium negative electrode. It has features that can be secured.

According to one embodiment, the ratio of the indium-lithium alloy layer and the coating layer containing the LIF may be 1:1 to 10:1.

Preferably, it may be 1:1 to 8:1, more preferably, it may be 2:1 to 7:1, and even more preferably, it may be 3:1 to 5:1.

The above ratio is a range that can maximize the performance of the protective film layer by maximizing the synergy effect of the indium-lithium alloy layer and the LiF film layer.

The protective film layer suppresses side reactions between the lithium electrode and the electrolyte solution, increases the reversibility of lithium electrodeposition and desorption reactions, and inhibits the formation of dendritic lithium, thereby improving the performance and stability of the lithium metal secondary battery.

According to one embodiment, the electrolyte solution includes a functional additive including lithium difluoro bis(oxalato)phosphate (LiDFBP) and lithium nitrate (LiNO ₃ ). Additionally, the functional additive may be included in an amount of 1% to 10% by weight in the electrolyte solution.

Preferably, the functional additive may be included in 3% to 10% by weight of the electrolyte solution, and more preferably, may be included in 4% to 8% by weight.

The functional additive may form a film on the surface of the lithium metal anode to reinforce the high-strength characteristics and high ionic conductivity characteristics of the lithium metal anode.

Hereinafter, the present invention will be described in more detail through examples and comparative examples.

However, the following examples are only for illustrating the present invention, and the content of the present invention is not limited to the following examples.

<Example> Preparation of electrolyte composition for indium plating, lithium metal electrode, and lithium metal secondary battery

1) Preparation of electrolyte composition for indium plating

An electrolyte composition for indium plating was prepared by mixing lithium salt, organic solvent, and indium ion additive. Additionally, for performance comparison, an electrolyte composition without indium ion additives was prepared.

The component composition of each electrolyte composition prepared is shown in Table 1.

Electrolyte composition for indium plating Example 1 2M LiFSI, DME, 1% In(TFSI) ₃ Example 2 2M LiFSI, DME/FEC (8/2, v/v), 1% In(TFSI) ₃ Comparative Example 1 2M LiFSI, DME/FEC (8/2, v/v)

2) Preparation of lithium metal electrode

In order to manufacture a lithium metal anode with an indium-lithium alloy layer formed, a battery consisting of an indium metal anode, a lithium metal anode, and an electrolyte composition for indium plating was manufactured. Afterwards, plating was performed by applying a charging current to allow indium ions to move from the indium metal anode to the lithium metal cathode. That is, by applying a current to the battery, indium was electrodeposited on the lithium surface through an oxidation reaction of the anode and a reduction reaction of the cathode, forming an alloy layer.

Indium additives have a lower LUMO compared to other materials in the electrolyte, so they are preferentially reduced on the surface of the lithium cathode.

3) Manufacturing of lithium metal secondary battery

A lithium metal secondary battery was manufactured using a lithium metal anode with an indium-lithium alloy layer formed on the surface, a copper (Cu) anode, and an electrolyte.

Figure 1 is a schematic diagram showing a method for manufacturing a lithium negative electrode plated with an indium-lithium alloy layer and a method for evaluating the reversibility of a battery manufactured using the same according to an embodiment of the present invention.

Referring to FIG. 1, it will be understood that a lithium metal electrode with an indium-lithium alloy layer formed on the surface of the lithium metal cathode can be manufactured by electrodepositing indium on the lithium surface using an indium anode, a lithium cathode, and an electrolyte composition for indium plating. You can.

In addition, it can be understood that the manufactured lithium metal electrode can be recovered and a lithium metal secondary battery using it as a negative electrode can be manufactured.

Figure 2 shows the HOMO/LUMO energy of each component included in the electrolyte composition for indium plating according to an embodiment of the present invention.

Referring to FIG. 2, it can be seen that the fluorine-based solvent also has low LUMO energy and is reduced and decomposed on the lithium metal surface during the electrodeposition process of indium ions to form a high-strength LiF film.

The formed LiF film can improve the reversibility of the cathode by physically inhibiting the growth of the lithium resin phase. Therefore, it can be seen that the reversibility of lithium can be greatly improved by working together with the indium-lithium alloy protective layer.

<Experimental Example 1> Reductive decomposition evaluation according to application of indium additive

Using Example 1 and Comparative Example 1, the degree of reductive decomposition of electrolyte solutions containing additives containing indium ions was evaluated through linear sweep voltammetry.

The experimental conditions are as follows.

1) Electrolyte

Comparative Example 1: 2M LiFSI + DME/FEC (8/2, v/v)

Example 1: 2M LiFSI + DME/FEC (8/2, v/v) + 1% In(TFSI) ₃

2) Separator

Polyethylene (PE) (thickness 15~16 ㎛, porosity 41%)

Figure 3 shows the reduction decomposition evaluation according to the application of indium additive.

Referring to Figure 3, it can be seen that when the In(TFSI) ₃ additive is applied, the amount of current due to reductive decomposition at a low potential of 2.0 V or less is greatly reduced.

This was thought to be due to the formation of an indium-lithium alloy layer due to reductive decomposition of the In(TFSI) ₃ additive in the 2.5 V range.

<Experimental Example 2> Confirmation of indium-lithium alloy layer formation on lithium metal electrode

Scanning Electron microscope analysis and Energy Dispersive X-ray Spectroscopy analysis were performed to confirm the indium-lithium alloy layer formed when an additive containing indium ions was used.

The experimental conditions are as follows.

1) Cell type: 1T spacer/20 lithium/16 separator/127 Indium, coin type cell (2032)

2) Experiment conditions: 1 hour aging at room temperature, current density (0.2 mAcm ^-2 ), capacity (2 mAhcm ^-2 )

3) Electrolyte

Comparative Example 1: 2M LiFSI + DME/FEC (8/2, v/v)

Example 2: 2M LiFSI + DME/FEC (8/2, v/v) + 1% In(TFSI) ₃

Figure 4 shows SEM images and EDS analysis results for the plated indium-lithium alloy layer.

Referring to FIG. 4, when an electrolyte for indium plating using an In(TFSI) ₃ additive is applied, it can be seen that much more indium exists on the lithium metal surface after the indium electrodeposition process in the indium-lithium cell.

This was believed to be because when an indium additive is applied, indium ions in the electrolyte exist closer to the lithium cathode, making electrodeposition easier.

<Experimental Example 3> Reversibility evaluation of lithium metal anode (ICE)

The reversibility of a lithium metal anode with an indium-lithium alloy layer formed on its surface was evaluated.

The experimental conditions are as follows.

1) Cell type: 1T spacer/20 lithium/16 separator/Cu, coin type cell (2032)

2) Experiment conditions: 1 hour aging at room temperature, current density (0.1 mAcm ^-2 ), capacity (1 mAhcm ^-2 )

3) Electrolyte: 2M LiFSI + DME + 5% LiNO ₃ + 1% LiDFBP

4) Electrolyte for indium plating

Pristine: No plating

Example 1 (DME + In(TFSI) ₃ ): 2M LiFSI + DME + 1% In(TFSI) ₃

Example 2 (DME/FEC + In(TFSI) ₃ ): 2M LiFSI + DME/FEC(8/2) + 1% In(TFSI) ₃

Figure 5 shows the results of reversibility evaluation of a lithium metal anode according to an embodiment of the present invention.

Referring to Figure 5, it can be seen that in the case of a lithium metal anode in which an indium-lithium alloy layer is formed through a plating electrolyte containing an In(TFSI) ₃ additive, initial reversibility is improved compared to an unplated pristine lithium anode.

Although the embodiments have been described with limited drawings as described above, those skilled in the art can apply various technical modifications and variations based on the above. For example, the described techniques are performed in a different order than the described method, and/or components of the described system, structure, device, circuit, etc. are combined or combined in a different form than the described method, or other components are used. Alternatively, appropriate results may be achieved even if substituted or substituted by an equivalent.

Therefore, other implementations, other embodiments, and equivalents of the claims also fall within the scope of the following claims.

Claims (15)

lithium salt;
Organic solvents, including a glyme-based solvent or a mixed solvent of a glyme-based solvent and a fluorine-based solvent; and
Additives containing indium ions (In ³⁺ );
Including,
The lithium salt is,
LiFOB, LiSO ₃ CF ₃ , LiDFBP, LiTFOP, LiPO ₂ F ₂ , LiB ₁₀ Cl ₁₀ , LiCF ₃ CO ₂ , CH ₃ SO ₃ Li, CF ₃ SO ₃ Li, LiSCN and LiC(CF ₃ SO ₂ ) ₃ Containing one or more selected from the group,
Electrolyte composition for indium plating of lithium electrodes.
According to paragraph 1,
The additive containing the indium ion is,
Containing at least one selected from the group consisting of indium nitrate (In(NO ₃ ) ₃ ), indium bis (trifluoromethanesulfonyl)imide (In(TFSI) ₃ ), and indium fluoride (InF ₃ ). thing,
Electrolyte composition for indium plating of lithium electrodes.
According to paragraph 1,
The additive containing the indium ion is,
Contained from 0.5% to 2% by weight,
Electrolyte composition for indium plating of lithium electrodes.
delete According to paragraph 1,
The concentration of the lithium salt is 1 M to 5 M,
Electrolyte composition for indium plating of lithium electrodes.
According to paragraph 1,
The glyme-based solvent is,
Containing at least one selected from the group consisting of dimethyl ether, 1,3-dioxolane, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, and tetraethylene glycol dimethyl ether,
Electrolyte composition for indium plating of lithium electrodes.
According to paragraph 1,
The fluorine-based solvent is,
Fluoroethylene carbonate (FEC), difluoroethylene carbonate (DFEC), 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetra fluoropropyl ether, 1,1,2,2 -at least one selected from the group consisting of tetrafluoroethyl-1H,1H,5H-octafluoropentyl ether and 1,1,2,2-tetrafluoroethyl-2,2,2-trifluoroethyl ether which includes,
Electrolyte composition for indium plating of lithium electrodes.
According to paragraph 1,
The volume ratio of the glyme-based solvent and the fluorine-based solvent is,
10:1 to 1:1,
Electrolyte composition for indium plating of lithium electrodes.
Lithium metal cathode; Indium metal anode; and an electrolyte solution containing the electrolyte composition for indium plating of claim 1; manufacturing an indium-lithium battery including; and
Applying current to the indium-lithium battery to form an indium-lithium alloy layer on the surface of the lithium metal anode;
Including,
Method for manufacturing lithium metal anode for lithium secondary battery.
According to clause 9,
A film layer containing LiF is simultaneously formed on the surface of the lithium metal cathode,
Method for manufacturing lithium metal anode for lithium secondary battery.
A lithium metal anode with a protective film layer formed on the surface of the lithium metal;
anode;
An electrolyte solution containing the electrolyte composition for indium plating of claim 1; and
separation membrane;
Including,
The protective film layer includes an indium-lithium alloy layer and a film layer containing LIF,
Lithium secondary battery.
According to clause 11,
The thickness of the protective film layer is 2 ㎛ to 8 ㎛,
Lithium secondary battery.
delete According to clause 11,
The ratio of the indium-lithium alloy layer and the coating layer containing the LIF is,
1:1 to 5:1,
Lithium secondary battery.
According to clause 11,
The electrolyte solution further includes a functional additive including lithium difluoro bis(oxalato)phosphate (LiDFBP) and lithium nitrate (LiNO ₃ ),
The functional additive is contained in 1% by weight to 10% by weight in the electrolyte solution,
Lithium secondary battery.

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