KR20230061936A - Compound and manufacturing method of the same - Google Patents

Abstract

The present invention relates to a silane-based compound capable of improving the performance of a battery when used as an electrode active material coating material, a non-aqueous electrolyte solution additive, and the like, and a method for preparing the same.

Description

Compound and its manufacturing method {COMPOUND AND MANUFACTURING METHOD OF THE SAME}

The present invention relates to a silane-based compound that can be used as an electrode active material coating material, a non-aqueous electrolyte solution additive, and the like, and a method for preparing the same.

As technology development and demand for mobile devices increase, demand for secondary batteries as an energy source is rapidly increasing. Among these secondary batteries, lithium secondary batteries having high energy density and voltage, long cycle life, and low self-discharge rate have been commercialized and widely used.

A lithium secondary battery is generally composed of a cathode active material made of lithium-containing transition metal oxide or a mixture of a carbon or silicon anode active material capable of occluding and releasing lithium ions, and optionally a binder and a conductive material, respectively, as a cathode current collector. and a negative electrode current collector to prepare a positive electrode and a negative electrode, and stacking them on both sides of a separator to form an electrode current collector of a predetermined shape, and then inserting the electrode current collector and the non-aqueous electrolyte into a battery case. Here, in order to secure the performance of the battery, it almost inevitably undergoes formation (formation) and aging (aging) processes. The formation process is a step of activating a secondary battery by repeating charging and discharging after assembling the battery, and during the charging, lithium ions from a lithium-containing transition metal oxide used as a positive electrode move to and insert into a carbonaceous negative electrode active material used as a negative electrode. do. At this time, highly reactive lithium ions react with the electrolyte to generate compounds such as Li ₂ CO ₃ , Li ₂ O, and LiOH, and these compounds form a solid electrolyte interface (SEI) layer on the surface of the electrode. The formation of the SEI layer is an important factor because the SEI layer closely affects lifespan and capacity retention. In recent years, especially in lithium secondary batteries for automobiles, high capacity, high output, and long lifespan characteristics have become important. In order to achieve high capacity, a positive electrode active material with high energy density but low stability is used on the positive electrode side, so it is necessary to form an active material-electrolyte interface that can stabilize the positive electrode active material by protecting the surface of the positive electrode active material. [0008] In [4], problems such as side reactions caused by decomposition of the surface species of the anode into the electrolyte have been reported, and thus the SEI layer needs to be formed to be robust and have low resistance. In addition, when stored at high temperature, the SEI layer gradually collapses and may cause problems such as electrode exposure, so attempts have been made to develop an additive in the electrolyte solution that helps to create an SEI interface that can suppress side reactions during high temperature storage. On the other hand, 1,3-propane sultone, 1,3,2-dioxathiolane 2,2-dioxide, etc., which are known to be effective in forming the SEI layer of the negative electrode, have problems such as gas generation and stability.

In addition, a lithium transition metal composite oxide is used as a cathode active material of a lithium secondary battery, and among them, a lithium cobalt composite metal oxide such as LiCoO ₂ having a high working voltage and excellent capacity characteristics is mainly used. However, LiCoO ₂ has poor thermal properties due to destabilization of the crystal structure due to delithiation. In addition, since the LiCoO ₂ is expensive, there is a limit to mass use as a power source in fields such as electric vehicles. As materials to replace the LiCoO ₂ , lithium manganese composite metal oxides (LiMnO ₂ or LiMn ₂ O _{4 ,} etc.), lithium iron phosphate compounds (LiFePO ₄ , etc.) or lithium nickel composite metal oxides (LiNiO _{2 ,} etc.) have been developed. . Among them, research and development on lithium-nickel composite metal oxide, which has a high reversible capacity of about 200 mAh/g and facilitates implementation of a large-capacity battery, is being actively researched. However, LiNiO ₂ has inferior thermal stability compared to LiCoO ₂ , and when an internal short circuit occurs due to pressure from the outside in a charged state, the cathode active material itself is decomposed, resulting in rupture and ignition of the battery. Accordingly, as a method for improving low thermal stability while maintaining excellent reversible capacity of LiNiO ₂ , a lithium transition metal oxide in which Ni is partially substituted with Co, Mn, or Al has been developed. In the case of a lithium secondary battery using such a lithium transition metal oxide, in particular, a lithium transition metal oxide containing a high amount of nickel (Ni-rich) as a cathode active material, the transition metal generated due to direct contact between the electrolyte and the cathode active material There is a problem in that the characteristics of the battery are deteriorated due to side reactions such as elution.

Finally, as an anode active material of a lithium secondary battery, a silicon-based anode material is used for high energy capacity. However, a battery including a silicon-based negative electrode material undergoes rapid volume expansion when charging/discharging is repeated several times or is left at a high temperature, thereby deteriorating life characteristics and high-temperature stability.

Accordingly, it is necessary to develop a compound that can be used as an electrode active material coating material, a non-aqueous electrolyte solution additive, etc. to improve battery performance.

An object of the present invention is to provide a silane-based compound capable of improving the performance of a battery when used as an electrode active material coating material, a non-aqueous electrolyte solution additive, and the like, and a method for preparing the same.

The present invention provides a compound represented by Formula I below.

[Formula I]

In the above formula I,

a, c are each independently an integer from 1 to 3, b is an integer from 0 to 2, a + b + c = 4,

n and m are each independently 1 or 2;

R ₁ and R ₂ are each independently hydrogen; Or a C ₁ -C ₁₀ alkyl group unsubstituted or substituted with a halogen group;

Ak ₁ , Ak ₂ , Ak ₃ is each independently a single bond; Or an unsubstituted C ₁ -C ₁₀ alkylene group;

Ak ₄ is an unsubstituted C ₁ -C ₁₀ alkylene group.

(However, in Formula I, the case where a, b, c, n, m are 1, 0, 3, 1, 1 in order and the case where 1, 1, 2, 1, 1 are excluded.)

And, the present invention relates to (A) preparing a compound represented by formula I through a hydrosilylation reaction of a compound represented by formula X and a compound represented by formula Y; Provides a method for producing a compound represented by

[Formula X]

In Formula X,

a' and c' are each independently an integer from 1 to 3, b is an integer from 0 to 2, a' + b' + c' = 4,

R ₁ and R ₂ are each independently hydrogen; Or a C ₁ -C ₁₀ alkyl group unsubstituted or substituted with a halogen group;

[Formula Y]

In the formula Y,

n and m are each independently 1 or 2;

Ak ₁ , Ak ₂ , Ak ₃ is each independently a single bond; Or an unsubstituted C ₁ -C ₁₀ alkylene group;

Ak ₄ is an unsubstituted C ₁ -C ₁₀ alkylene group.

When the compound represented by Formula I according to the present invention is used as an electrode active material coating material, a non-aqueous electrolyte solution additive, etc., the performance of a finally manufactured battery can be improved.

1 is a ¹ H-NMR spectrum of the compound represented by Formula b prepared in Example 2.

Hereinafter, the present invention will be described in more detail.

The terms or words used in this specification and claims should not be construed as being limited to ordinary or dictionary meanings, and the inventors may appropriately define the concept of terms in order to explain their invention in the best way. It should be interpreted as a meaning and concept consistent with the technical idea of the present invention based on the principle that there is.

Terms used in this specification are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, terms such as 'include' or 'have' designate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, but one or more other It should be understood that the presence or addition of features, numbers, steps, operations, components, parts, or combinations thereof is not precluded.

In this specification, the term 'on' means not only a case where a certain element is formed directly on top of another element, but also a case where a third element is interposed between these elements.

In the present specification, the average particle diameter (D ₅₀ ) may be defined as a particle diameter corresponding to 50% of the cumulative volume in the particle size distribution curve (graph curve of the particle size distribution) of each particle. The D ₅₀ can be measured using, for example, a laser diffraction method. The laser diffraction method is generally capable of measuring particle diameters of several millimeters in the submicron region, and can obtain results with high reproducibility and high resolution.

Compound represented by Formula I

The present invention provides a compound represented by Formula I below.

[Formula I]

In the above formula I,

a, c are each independently an integer from 1 to 3, b is an integer from 0 to 2, a + b + c = 4,

n and m are each independently 1 or 2;

R ₁ and R ₂ are each independently hydrogen; Or a C ₁ -C ₁₀ alkyl group unsubstituted or substituted with a halogen group;

Ak ₁ , Ak ₂ , Ak ₃ is each independently a single bond; Or an unsubstituted C ₁ -C ₁₀ alkylene group;

Ak ₄ is an unsubstituted C ₁ -C ₁₀ alkylene group.

(However, in Formula I, the case where a, b, c, n, m are 1, 0, 3, 1, 1 in order and the case where 1, 1, 2, 1, 1 are excluded.)

When the compound represented by Formula I is used as an electrode active material coating material, it is possible to form a coating layer having the same or similar role as the SEI layer on the surface of the electrode active material, thereby improving the surface stability of the electrode active material. , It is possible to improve the lifespan characteristics and stability of a secondary battery including such an electrode active material.

For example, when the compound represented by the formula (I) is used as a coating material for the positive electrode active material, a coating layer derived from the compound represented by the formula (I) is formed on the surface of the positive electrode active material, and the coating layer contains a cyano group to The elution of the transition metal is suppressed, and even if the transition metal is eluted, the transfer of the transition metal to the negative electrode through a coordination bond is prevented, thereby improving the lifespan of the battery. And, even when the compound represented by Formula I is used as a coating material for the negative electrode active material, a coating layer derived from the compound represented by Formula I is formed on the surface of the negative electrode active material, and the coating layer can improve surface stability of the negative electrode active material. In addition, it can adsorb transition metals eluted from the cathode active material. On the other hand, when a CN group is present at the terminal, as in the compound represented by Formula I, the coordination bond between the unshared electron pair of the nitrogen element and the eluted transition metal ion can be better formed because of the small steric hindrance.

In addition, when the compound represented by Formula I is included in the non-aqueous electrolyte, side reactions inside the battery due to metal ions eluted from the electrode can be suppressed, and thus high-temperature stability and lifespan characteristics of the battery can be improved. Specifically, the compound represented by Formula I contains a cyano group and when a transition metal is eluted, suppresses elution through multidentate coordination and forms a complex to form a stable ion conductive film on the surface of the anode. Side reactions can be inhibited. Moreover, even in the state where no film is formed, metal ions eluted from the anode can be adsorbed and electrodeposited to the cathode can be suppressed.

According to the present invention, the compound represented by Formula I may be any one of the compounds represented by Formulas 1 to 4 below.

[Formula 1]

In Formula 1,

n1 and m1 are each independently 1 or 2,

R ₁ is hydrogen; Or a C ₁ -C ₁₀ alkyl group unsubstituted or substituted with a halogen group;

Ak ₁ , Ak ₂ , Ak ₃ is each independently a single bond; Or an unsubstituted C ₁ -C ₁₀ alkylene group;

Ak ₄ is an unsubstituted C ₁ -C ₁₀ alkylene group.

(However, the case where n1 and m1 are both 1 in Formula 1 is excluded.)

[Formula 2]

In Formula 2,

n2 and m2 are each independently 1 or 2,

R ₁ and R ₂ are each independently hydrogen; Or a C ₁ -C ₁₀ alkyl group unsubstituted or substituted with a halogen group;

Ak ₁ , Ak ₂ , Ak ₃ is each independently a single bond; Or an unsubstituted C ₁ -C ₁₀ alkylene group;

Ak ₄ is an unsubstituted C ₁ -C ₁₀ alkylene group.

(However, in Formula 2, the case where n2 and m2 are both 1 is excluded.)

[Formula 3]

In Formula 3,

n3 and m3 are each independently 1 or 2,

R ₁ and R ₂ are each independently hydrogen; Or a C ₁ -C ₁₀ alkyl group unsubstituted or substituted with a halogen group;

Ak ₁ , Ak ₂ , Ak ₃ is each independently a single bond; Or an unsubstituted C ₁ -C ₁₀ alkylene group;

Ak ₄ is an unsubstituted C ₁ -C ₁₀ alkylene group.

[Formula 4]

In Formula 4,

n4 and m4 are each independently 1 or 2,

R ₁ is hydrogen; Or a C ₁ -C ₁₀ alkyl group unsubstituted or substituted with a halogen group;

Ak ₁ , Ak ₂ , Ak ₃ is each independently a single bond; Or an unsubstituted C ₁ -C ₁₀ alkylene group;

Ak ₄ is an unsubstituted C ₁ -C ₁₀ alkylene group.

In view of the ease of synthesis of the compound represented by Formula I and the compound represented by Formulas 1 to 4, R ₁ and R ₂ are each independently hydrogen; Or it may be a C ₁ -C ₆ alkyl group substituted or unsubstituted with a halogen group, wherein Ak ₁ , Ak ₃ is each independently a single bond; Or it may be an unsubstituted C ₁ -C ₆ alkylene group, wherein Ak ₂ , Ak ₄ may each independently be an unsubstituted C ₁ -C ₆ alkylene group.

According to the present invention, the compound represented by Formula I may be a compound represented by Formulas a to h below.

[Formula a]

[Formula b]

[Formula c]

[Formula d]

[Formula e]

[Formula f]

[Formula g]

[Formula h]

.

.

Method for preparing the compound represented by Formula I

And, the present invention relates to (A) preparing a compound represented by formula I through a hydrosilylation reaction of a compound represented by formula X and a compound represented by formula Y; Provides a method for producing a compound represented by

[Formula X]

In Formula X,

a' and c' are each independently an integer from 1 to 3, b is an integer from 0 to 2, a' + b' + c' = 4,

R ₁ and R ₂ are each independently hydrogen; Or a C ₁ -C ₁₀ alkyl group unsubstituted or substituted with a halogen group;

[Formula Y]

In the formula Y,

n and m are each independently 1 or 2;

Ak ₁ , Ak ₂ , Ak ₃ is each independently a single bond; Or an unsubstituted C ₁ -C ₁₀ alkylene group;

Ak ₄ is an unsubstituted C ₁ -C ₁₀ alkylene group.

According to the present invention, the hydrosilylation reaction may be performed in the presence of a platinum-based catalyst to reduce side reactions and increase yield. For example, it may be performed in the presence of Karstedt's catalyst.

According to the present invention, the hydrosilylation reaction may be carried out at a temperature of 70 °C to 200 °C, specifically 80 °C to 140 °C, in order to activate the catalyst.

According to the present invention, the hydrosilylation reaction may be carried out in a toluene solvent in terms of ease of purification.

Hereinafter, the present invention will be described in more detail through specific examples. However, the following examples are only examples to help understanding of the present invention, and do not limit the scope of the present invention. It is obvious to those skilled in the art that various changes and modifications are possible within the scope and spirit of the present disclosure, and it is natural that such changes and modifications fall within the scope of the appended claims.

Example

Example 1. Preparation of the compound represented by Formula (a)

20 ml of anhydrous dichloromethane and 3.32 g (1 equivalent) of 3-hydroxyglutaronitrile (hereinafter referred to as HGN) were dissolved in a 100 ml round bottom flask, and 0.944 g (1.3 equivalent) of NaH was added at 0 ° C. After that, it was stirred for 1 hour. Then, 1.72 ml (1.1 equivalent) of allyl bromide was slowly added dropwise, followed by reaction while stirring at room temperature until HGN was completely consumed. After completion of the reaction, the mixture was passed through a celite filter and sufficiently washed with dichloromethane. After concentrating the solution with a rotary evaporator, the material was purified through a silica column (ethyl acetate:hexane=1:3) to obtain 0.2 g of a compound represented by Formula X-1 below.

[Formula X-1]

In a 50ml round bottom flask, add 0.2g (1.05 equivalent) of the compound represented by Formula X-1 and 0.008g (0.001 equivalent) of Karstedt's catalyst, which is a Pt (0) catalyst, and stir, and then add 0.15g (1 equivalent) of triethoxysilane. and 5 ml of toluene were added, and reacted with stirring at 100° C. for 1 hour to obtain 0.3 g of a compound represented by Formula (a) below.

[Formula a]

Synthesis of the compound represented by Formula (a) was confirmed by ¹ H-NMR spectrum (Bruker Co., AVANCE NEO), and ¹ H-NMR data are as follows.

¹ H-NMR (400 MHz, DMSO): δ (ppm) = 0.56 (2H, t), 1.21 (9H, t), 1.42 (2H, q), 2.52 (4H, d), 3.3 (1H, m), 3.35 (2H, m), 3.83 (6H, m)

Example 2. Preparation of the compound represented by formula (b)

After placing the 100ml round-bottom flask in an ice-bath, 3-butene-1,2-diol (3-butene-1,2-diol) 3g (1 equivalent) and acrylonitrile (acrylonitrile) 11.6 ml (5 equivalents) was added and stirred for 10 minutes or more. Then, after slowly adding 0.5 ml of tetramethylammonium hydroxide (TMAH) dropwise, the mixture was reacted with stirring while maintaining 0°C until all 3-butene-1,2-diol was consumed. When 3-butene-1,2-diol was exhausted, the reaction was quenched with 1N HCl, and extracted using ethyl acetate and brine. The material was purified through a silica column (ethyl acetate:hexane = 1:3) to obtain 7 g of a compound represented by Formula X-2 below.

[Formula X-2]

In a 50ml round bottom flask, add 0.5g (1.05 equivalent) of the compound represented by Formula X-2 and 0.0018g (0.001 equivalent) of Karstedt's catalyst, which is a Pt (0) catalyst, and stir, and then add 0.4g (1 equivalent) of triethoxysilane. and 5 ml of toluene were added, and reacted with stirring at 100° C. for 1 hour to obtain 0.8 g of a compound represented by Formula b below.

Synthesis of the compound represented by Formula b was confirmed by ¹ H-NMR spectrum (Bruker, AVANCE NEO), and ^{the 1} H-NMR spectrum of the compound represented by Formula b is shown in FIG. 1 .

[Formula b]

Example 3. Preparation of the compound represented by formula c

In a 50ml round bottom flask, add 0.2g (1.05 equivalent) of the compound represented by Formula X-1 prepared in the same manner as in Example 1 and 0.008g (0.001 equivalent) of Karstedt's catalyst, which is a Pt (0) catalyst, and stir. 0.12 g (1 equivalent) of diethoxy methyl silane and 5 ml of toluene were added and reacted with stirring at 100° C. for 1 hour to obtain 0.3 g of a compound represented by Formula c below.

[Formula c]

Synthesis of the compound represented by Formula c was confirmed by ¹ H-NMR spectrum (Bruker, AVANCE NEO), and ¹ H-NMR data are as follows.

¹ H-NMR (400 MHz, DMSO): δ (ppm) = 0.14 (3H, s), 0.61 (2H, t), 1.21 (6H, t), 1.42 (2H, m), 2.52 (4H, d), 3.3 (1H, m), 3.35 (2H, m), 3.83 (4H, m)

Example 4. Preparation of the compound represented by formula d

0.5 g (1.05 equivalent) of the compound represented by Formula X-2 prepared in the same manner as in Example 2 and 0.0018 g (0.001 equivalent) of Karstedt's catalyst, which is a Pt (0) catalyst, were added to a 50 ml round bottom flask and stirred. 0.4 g (1 equivalent) of diethoxy methyl silane and 5 ml of toluene were added and reacted with stirring at 100° C. for 1 hour to obtain 0.8 g of a compound represented by Formula d below.

[Formula d]

Synthesis of the compound represented by Formula d was confirmed by ¹ H-NMR spectrum (Bruker, AVANCE NEO), and ¹ H-NMR data are as follows.

¹ H-NMR (400 MHz, DMSO): δ (ppm) = 0.14 (3H, s), 0.61 (2H, t), 1.21 (6H, t), 1.36 (2H, m), 2.58 (4H, t), 3.35 to 3.74 (7H, m), 3.83 (4H, m)

Example 5. Preparation of the compound represented by Formula e

In a 100ml round bottom flask, 20ml of anhydrous dichloromethane and 2g (1 equivalent) of 3-hydroxypropanenitrile were dissolved, and 0.944g (1.3 equivalent) of NaH was added thereto at 0° C., followed by stirring for 1 hour. . Then, 1.72 ml (1.1 equivalent) of allyl bromide was slowly added dropwise, followed by reaction at room temperature with stirring until all 3-hydroxypropanenitrile was consumed. After completion of the reaction, the mixture was passed through a celite filter and sufficiently washed with dichloromethane. After concentrating the solution with a rotary evaporator, the material was purified through a silica column (ethyl acetate:hexane = 1:3) to obtain 1.8 g of a compound represented by Formula X-3 below.

[Formula X-3]

In a 50ml round bottom flask, 0.13 g (1.05 equivalent) of the compound represented by Formula X-3 and 0.008 g (0.001 equivalent) of Karstedt's catalyst, which is a Pt (0) catalyst, were stirred, and then 0.15 ethoxy dimethyl silane g (1 equivalent) and 5 ml of toluene were added, and reacted with stirring at 100° C. for 1 hour to obtain 0.2 g of a compound represented by Formula e below.

[Formula e]

Synthesis of the compound represented by Formula e was confirmed by ¹ H-NMR spectrum (Bruker, AVANCE NEO), and ¹ H-NMR data are as follows.

¹ H-NMR (400 MHz, DMSO): δ (ppm) = 0.21 (6H, s), 1.21 (3H, t), 1.42 (2H, m), 2.58 (2H, t), 3.35 (2H, t), 3.74 (2H, t), 3.83 (3H, m)

Example 6. Preparation of the compound represented by formula f

In a 50ml round bottom flask, add 0.2g (1.05 equivalent) of the compound represented by Formula X-1 prepared in the same manner as in Example 1 and 0.008g (0.001 equivalent) of Karstedt's catalyst, which is a Pt (0) catalyst, and stir. 0.17 g (1 equivalent) of ethoxy dimethyl silane and 5 ml of toluene were added, and reacted with stirring at 100° C. for 1 hour to obtain 0.3 g of a compound represented by Formula f below.

[Formula f]

Synthesis of the compound represented by Formula f was confirmed by ¹ H-NMR spectrum (Bruker, AVANCE NEO), and ¹ H-NMR data are as follows.

¹ H-NMR (400 MHz, DMSO): δ (ppm) = 0.21 (6H, s), 0.61 (2H, t), 1.21 (3H, t), 1.42 (2H, m), 2.52 (4H, d), 3.3 (1H, m), 3.35 (2H, m), 3.83 (2H, q)

Example 7. Preparation of the compound represented by formula g

0.5 g (1.05 equivalent) of the compound represented by Formula X-2 prepared in the same manner as in Example 2 and 0.0018 g (0.001 equivalent) of Karstedt's catalyst, which is a Pt (0) catalyst, were added to a 50 ml round bottom flask and stirred. 0.4 g (1 equivalent) of ethoxy dimethyl silane and 5 ml of toluene were added and reacted with stirring at 100° C. for 1 hour to obtain 0.8 g of a compound represented by Formula g below.

[Formula g]

Synthesis of the compound represented by Formula g was confirmed by ¹ H-NMR spectrum (Bruker, AVANCE NEO), and ¹ H-NMR data are as follows.

¹ H-NMR (400 MHz, DMSO): δ (ppm) = 0.21 (6H, s), 0.61 (2H, t), 1.21 (3H, t), 1.36 (2H, m), 2.58 (4H, t), 3.35 to 3.74 (7H, m), 3.83 (2H, m)

Example 8. Preparation of the compound represented by formula h

In a 50ml round bottom flask, 0.23 g (2.1 equivalent) of the compound represented by Formula X-3 prepared in the same manner as in Example 5 and 0.008 g (0.001 equivalent) of Karstedt's catalyst, which is a Pt (0) catalyst, were added and stirred, 0.12 g (1 equivalent) of ethoxy dimethyl silane and 5 ml of toluene were added and reacted with stirring at 100° C. for 1 hour to obtain 0.2 g of a compound represented by Formula h below.

[Formula h]

Synthesis of the compound represented by Chemical Formula h was confirmed through ¹ H-NMR spectrum (Bruker, AVANCE NEO), and ¹ H-NMR data are as follows.

¹ H-NMR (400 MHz, DMSO): δ (ppm) = 0.61 (4H, t), 1.21 (6H, t), 1.42 (4H, m), 2.58 (4H, t), 3.35 (4H, t), 3.74(4H, t), 3.83(4H, q)

Experimental example

Experimental Example 1: Confirmation of effect when used as a non-aqueous electrolyte additive

(Manufacture of non-aqueous electrolyte solution)

A non-aqueous electrolyte solution was prepared by adding additives as shown in Table 1 below to an organic solvent (ethylene carbonate (EC):ethylmethyl carbonate (EMC) = 3:7 volume ratio) in which 1.0M LiPF ₆ was dissolved.

(Secondary battery manufacturing)

Cathode active material (LiNi _0.8 Co _0.1 Mn _0.1 O ₂ ): _conductive material (carbon black):binder (polyvinylidene fluoride) in a weight ratio of 97.5:1:1.5 N-methyl-2-pyrrolidone (NMP) was added to prepare a slurry for a positive electrode (60% by weight of solid content). The positive electrode slurry was applied to one surface of a positive electrode current collector (Al thin film) having a thickness of 15 μm, and dried and roll pressed to prepare a positive electrode.

A negative electrode active material (graphite):conductive material (carbon black):binder (polyvinylidene fluoride) was added to distilled water in a weight ratio of 96:0.5:3.5 to prepare a slurry (solid content: 50% by weight). The negative electrode slurry was coated on one surface of a positive electrode current collector (Cu thin film) having a thickness of 8 μm, and dried and roll pressed to prepare a negative electrode.

After preparing an electrode assembly by placing a porous polypropylene separator between the positive electrode and the negative electrode in a dry room, inserting it into a battery case, injecting each non-aqueous electrolyte solution, and sealing it to obtain a pouch-type lithium secondary battery (battery capacity: 6.24mAh). ) was prepared.

lithium salt organic solvent additive composition Amount added (g) type Amount added (g) Experimental Example 1-1 1.0 LiPF ₆ EC:EMC = 3:7 volume ratio 99 The compound represented by formula (a) of Example 1 One Experimental Example 1-2 99 The compound represented by formula b of Example 2 One Experimental Example 1-3 99 The compound represented by formula c of Example 3 One Experimental Example 1-4 99 The compound represented by formula d of Example 4 One Comparative Experimental Example 1-1 100 - - Comparative Experimental Example 1-2 99 DMSCN One Comparative Experimental Example 1-3 99 DESCN One

The structures of DMSCN and DESCN, which are additives used in Comparative Experimental Example 1-2 and Comparative Experimental Example 1-3, are as follows.

(DMSCN)

(DESCN)

- Evaluation of storage characteristics at high temperature (60℃)

Each of the secondary batteries manufactured according to Experimental Examples 1-1 to 1-4 and Comparative Experimental Examples 1-1 to 1-3 was activated with 0.1C constant current (CC). Subsequently, it was charged with 0.33C constant current to 4.2V under constant current-constant voltage (CC-CV) charging conditions at 25 ° C, followed by a 0.05C current cut, and discharged at 0.33C to 2.5V under CC conditions. Two cycles were performed with the charging and discharging as one cycle. Subsequently, fully charged with 0.33C constant current up to 4.2V under CC-CV charging conditions, adjusted SOC to 50% SOC, and then discharged at 2.5C for 10 seconds. was calculated. Then, it was discharged until it became 2.5V with 0.33C constant current. Subsequently, degas was performed, and the initially charged and discharged lithium secondary battery was put into a bowl filled with water at room temperature using Two-pls' TWD-150DM equipment to measure the initial volume. Then, the lithium secondary battery was fully charged at 0.33C/4.2V constant current-constant voltage, stored at 60°C for 4 weeks (SOC 100%), and then watered at room temperature using Two-pls' TWD-150DM equipment. A lithium secondary battery was put into a filled bowl and the volume after high-temperature storage was measured.

The volume change rate (%) was calculated by substituting the measured initial volume and the volume after high temperature storage into the following formula (1), and it is shown in Table 2 below.

Equation (1): Volume change rate after high temperature storage (%) = {(volume after high temperature storage - initial volume) / (initial volume)} × 100

- Evaluation of cycle characteristics

Each of the secondary batteries manufactured according to Experimental Examples 1-1 to 1-4 and Comparative Experimental Examples 1-1 to 1-3 was activated with 0.1C constant current (CC). Subsequently, it was charged with 0.33C constant current to 4.2V under constant current-constant voltage (CC-CV) charging conditions at 25 ° C, followed by a 0.05C current cut, and discharged at 0.33C to 2.5V under CC conditions. Two cycles were performed with the charging and discharging as one cycle. Subsequently, fully charged with 0.33C constant current up to 4.2V under CC-CV charging conditions, adjusted SOC to 50% SOC, and then discharged at 2.5C for 10 seconds. was calculated. Then, it was discharged until it became 2.5V with 0.33C constant current.

Subsequently, degas was performed, and charging was performed with 0.33C constant current up to 4.2V under CC-CV charging conditions at 45°C, followed by 0.05C current cut, and after leaving it for 20 minutes, it was left at 0.33C up to 2.5V under CC conditions. discharged. 100 cycles were performed with the charging and discharging as one cycle. At this time, the discharge capacity after the first cycle (initial discharge capacity) and the discharge capacity after the 100th cycle were measured. The discharge capacity retention rate after 100 cycles was calculated using Equation (2) below, and the results are shown in Table 2 below.

Equation (2): Discharge capacity retention rate after 100 cycles (%) = {(discharge capacity after 100 cycles)/initial discharge capacity} × 100

Volume change rate after high temperature storage (%) Discharge capacity retention rate after 100 cycles (%) Experimental Example 1-1 8 94 Experimental Example 1-2 10 92 Experimental Example 1-3 9 95 Experimental Example 1-4 9 93 Comparative Experimental Example 1-1 37 78 Comparative Experimental Example 1-2 14 87 Comparative Experimental Example 1-3 16 88

Referring to Table 2, it can be confirmed that the secondary battery prepared according to Experimental Examples 1-1 to 1-4 has a significantly lower volume change rate even after storage at a high temperature than the secondary battery manufactured according to Experimental Examples 1-1 to 1-3. there is. In addition, it can be seen that the secondary batteries manufactured according to Experimental Examples 1-1 to 1-4 have significantly better lifespan characteristics than the secondary batteries manufactured according to Experimental Examples 1-1 to 1-3. These characteristics are such that the compound represented by Formula I contained in the non-aqueous electrolyte of the secondary battery prepared according to Experimental Examples 1-1 to 1-4 adsorbs metal ions eluted from the electrode, thereby preventing the inside of the battery that may be generated by metal ions. This is because side reactions are suppressed and stability is increased.

Experimental Example 2: Checking the effect of using a cathode active material as a coating material

(Manufacture of cathode active material coated with coating layer)

After adding lithium transition metal oxide having a composition represented by LiNi _0.8 Co _0.1 Mn _0.1 O ₂ to 27 g of toluene and having an average particle diameter (D ₅₀ ) of 10 μm, 27 g of a positive electrode active material and a positive electrode active material coating material as shown in Table 3, The mixture was stirred and reacted at room temperature for 12 hours. After completion of the reaction, the mixture was filtered and dried in a vacuum oven at 200° C. for 1 hour to remove the solvent, thereby forming a coating layer on the surface of the positive electrode active material.

(Manufacture of lithium secondary battery)

Cathode active material coated with the coating layer prepared in the above (preparation of cathode active material coated with coating layer): conductive material (carbon black): binder (polyvinylidene fluoride) at a weight ratio of 97.5: 1: 1.5 N-methyl-2- It was added to pyrrolidone (NMP) to prepare a positive electrode active material slurry (solid content concentration: 60% by weight). The positive electrode active material slurry was coated on one surface of a positive electrode current collector (Al thin film) having a thickness of 15 μm, and dried and roll pressed to prepare a positive electrode.

A negative active material (graphite):conductive material (carbon black):binder (polyvinylidene fluoride) was added to distilled water in a weight ratio of 96:0.5:3.5 to prepare a negative active material slurry (solid content: 50% by weight). The negative electrode active material slurry was coated on one surface of a positive electrode current collector (Cu thin film) having a thickness of 8 μm, and dried and roll pressed to prepare a negative electrode.

A non-aqueous electrolyte was prepared by adding 1.5 g of vinylene carbonate (VC) to 98.5 g of an organic solvent (ethylene carbonate (EC):ethylmethyl carbonate (EMC) = 3:7 volume ratio) in which 1.0M LiPF ₆ was dissolved.

After preparing an electrode assembly by interposing a porous polyethylene separator between the positive electrode and the negative electrode, the electrode assembly was placed in a battery case, the non-aqueous electrolyte was injected, and sealed to prepare a pouch-type lithium secondary battery (battery capacity: 6.24 mAh).

Cathode active material coating material type Input amount (g) Experimental example 2-1 The compound represented by formula (a) of Example 1 3 Experimental Example 2-2 The compound represented by formula b of Example 2 3 Experimental example 2-3 The compound represented by formula c of Example 3 3 Experimental Example 2-4 The compound represented by formula d of Example 4 3 Comparative Experimental Example 2-1 - - Comparative Experimental Example 2-2 DMSCN 3

- Evaluation of initial discharge capacity

After activating each of the secondary batteries prepared according to Experimental Examples 2-1 to 2-4 and Comparative Experimental Examples 2-1 to 2-2 with 0.1C constant current (CC) at 25 ° C, constant current-constant voltage (CC- CV) Charged with 0.33C constant current to 4.2V under charging conditions, then 0.05C current cut was performed, and discharged at 0.33C to 2.5V under CC conditions. 3 cycles were performed with the charging and discharging as one cycle. Subsequently, the initial discharge capacity was measured using a PNE-0506 charger and discharger (PNE Solution Co., Ltd., 5V, 6A), and is shown in Table 4 below.

- Evaluation of transition metal elution amount

After activating each of the secondary batteries prepared according to Experimental Examples 2-1 to 2-4 and Comparative Experimental Examples 2-1 to 2-2 at 25° C. with 0.1C constant current (CC), charge and discharge were performed for 3 cycles. After that, it was charged with 0.33C constant current up to 4.2V under constant current-constant voltage (CC-CV) charging conditions at 25 °C. After charging, the battery is disassembled, the positive electrode is taken out, put into a non-aqueous electrolyte (an organic solvent in which 1.0M LiPF ₆ is dissolved (ethylene carbonate (EC): ethylmethyl carbonate (EMC) = 3:7 volume ratio)), and then sealed to 60 Stored at °C for 1 week. After one week, each non-aqueous electrolyte was taken, and the Ni elution amount obtained from the ICP-OES analyzer (Perkinelmer Co.) is shown in Table 4 below.

Initial discharge capacity (mAh/g) Ni elution amount (ppm) Experimental Example 2-1 202 86 Experimental Example 2-2 204 88 Experimental example 2-3 203 89 Experimental example 2-4 203 88 Comparative Experimental Example 2-1 198 120 Comparative Experimental Example 2-2 202 100

Referring to Table 4, in the case of a secondary battery using a cathode active material having a coating layer formed by using the compound represented by Formula I according to the present invention as a cathode active material coating material, Comparative Experimental Example 2- using a cathode active material not coated with a coating layer Compared to the secondary battery of No. 1, it can be seen that the initial discharge capacity is improved and the amount of Ni elution is reduced. From these results, when the compound of Formula I according to the present invention is used as a coating material for the positive electrode active material, the formed coating layer prevents side reactions between the positive electrode active material and the electrolyte and prevents the layer structure of the positive electrode active material from collapsing, thereby preventing the elution of the transition metal. know that you can.

Claims (9)

A compound represented by Formula I:
[Formula I]

In the above formula I,
a, c are each independently an integer from 1 to 3, b is an integer from 0 to 2, a + b + c = 4,
n and m are each independently 1 or 2;
R ₁ and R ₂ are each independently hydrogen; Or a C ₁ -C ₁₀ alkyl group unsubstituted or substituted with a halogen group;
Ak ₁ , Ak ₂ , Ak ₃ is each independently a single bond; Or an unsubstituted C ₁ -C ₁₀ alkylene group;
Ak ₄ is an unsubstituted C ₁ -C ₁₀ alkylene group.
(However, in Formula I, the case where a, b, c, n, m are 1, 0, 3, 1, 1 in order and the case where 1, 1, 2, 1, 1 are excluded.)
The method of claim 1,
The compound represented by Formula I is a compound represented by Formula 1 below:
[Formula 1]

In Formula 1,
n1 and m1 are each independently 1 or 2,
R ₁ is hydrogen; Or a C ₁ -C ₁₀ alkyl group unsubstituted or substituted with a halogen group;
Ak ₁ , Ak ₂ , Ak ₃ is each independently a single bond; Or an unsubstituted C ₁ -C ₁₀ alkylene group;
Ak ₄ is an unsubstituted C ₁ -C ₁₀ alkylene group.
(However, the case where n1 and m1 are both 1 in Formula 1 is excluded.)
The method of claim 1,
The compound represented by Formula I is a compound represented by Formula 2 below:
[Formula 2]

In Formula 2,
n2 and m2 are each independently 1 or 2,
R ₁ and R ₂ are each independently hydrogen; Or a C ₁ -C ₁₀ alkyl group unsubstituted or substituted with a halogen group;
Ak ₁ , Ak ₂ , Ak ₃ is each independently a single bond; Or an unsubstituted C ₁ -C ₁₀ alkylene group;
Ak ₄ is an unsubstituted C ₁ -C ₁₀ alkylene group.
(However, in Formula 2, the case where n2 and m2 are both 1 is excluded.)
The method of claim 1,
The compound represented by Formula I is a compound represented by Formula 3 below:
[Formula 3]

In Formula 3,
n3 and m3 are each independently 1 or 2,
R ₁ and R ₂ are each independently hydrogen; Or a C ₁ -C ₁₀ alkyl group unsubstituted or substituted with a halogen group;
Ak ₁ , Ak ₂ , Ak ₃ is each independently a single bond; Or an unsubstituted C ₁ -C ₁₀ alkylene group;
Ak ₄ is an unsubstituted C ₁ -C ₁₀ alkylene group.
The method of claim 1,
The compound represented by Formula I is a compound represented by the following Formula 4:
[Formula 4]

In Formula 4,
n4 and m4 are each independently 1 or 2,
R ₁ is hydrogen; Or a C ₁ -C ₁₀ alkyl group unsubstituted or substituted with a halogen group;
Ak ₁ , Ak ₂ , Ak ₃ is each independently a single bond; Or an unsubstituted C ₁ -C ₁₀ alkylene group;
Ak ₄ is an unsubstituted C ₁ -C ₁₀ alkylene group.
The method of claim 1,
The compound represented by Formula I is a compound represented by the following Formulas a to h:
[Formula a]

[Formula b]

[Formula c]

[Formula d]

[Formula e]

[Formula f]

[Formula g]

[Formula h]

.
(A) preparing a compound represented by Formula I through a hydrosilylation reaction of a compound represented by Formula X and a compound represented by Formula Y; :
[Formula X]

In Formula X,
a' and c' are each independently an integer from 1 to 3, b is an integer from 0 to 2, a' + b' + c' = 4,
R ₁ and R ₂ are each independently hydrogen; Or a C ₁ -C ₁₀ alkyl group unsubstituted or substituted with a halogen group;
[Formula Y]

In the formula Y,
n and m are each independently 1 or 2;
Ak ₁ , Ak ₂ , Ak ₃ is each independently a single bond; Or an unsubstituted C ₁ -C ₁₀ alkylene group;
Ak ₄ is an unsubstituted C ₁ -C ₁₀ alkylene group.
The method of claim 7,
The hydrosilylation reaction is a method for producing a compound that is carried out in the presence of a platinum-based catalyst.
The method of claim 7,
The hydrogen silylation reaction is a method for producing a compound that is carried out at a temperature of 70 ℃ to 200 ℃.

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