KR102615538B1 - Flame-retardant gel electrolyte and energy storage device including the same - Google Patents

Abstract

The present invention relates to a flame-retardant gel electrolyte and an energy storage device containing the same. One aspect of the present invention provides a flame-retardant gel electrolyte containing a compound represented by the following formula (1).
[Formula 1]

In Formula 1, n, m and l are each integers from 1 to 1,000, and at least one of A, B and C is -OCO(CF ₂ ) _x CF ₃ or -OCOR ¹ (CF ₂ ) _x CF ₃ , and among A, B and C -OCO(CF ₂ ) _x CF ₃ or ^{-OCOR 1} _{( CF 2} ^{) _ _ _} It is a substituted C _1-10 alkyl group, x is an integer of 1 to 10, and R ² is a substituted or unsubstituted C _1-10 alkyl group.

Description

Flame-retardant gel electrolyte and energy storage device containing the same {FLAME-RETARDANT GEL ELECTROLYTE AND ENERGY STORAGE DEVICE INCLUDING THE SAME}

The present invention relates to a flame-retardant gel electrolyte and an energy storage device containing the same.

As batteries, which were mainly used in small IT devices such as smartphones and laptops, are expanding to electric vehicles, energy storage systems (ESS), and electric equipment, there is a need for the development of batteries with high capacity and high energy density.

In addition, in order for batteries to be applied to special industries such as electric vehicles, aviation, shipbuilding, national defense, and medicine, a much higher level of reliability and stability is required than batteries used in everyday life, and as stability issues with lithium secondary batteries continue to be raised. Accordingly, technology development is underway to ensure not only battery performance but also stability.

One of the main technologies currently being developed related to battery stability is replacing liquid electrolyte or gel electrolyte with solid electrolyte to reduce the risk of explosion and fire that exists in existing secondary batteries using liquid electrolyte or gel electrolyte. This is a technology related to all-solid-state batteries.

However, all-solid-state batteries have the disadvantages of low battery output due to low ion movement speed, high resistance at the interface between the electrolyte and the anode and cathode, and lower lifespan compared to conventional batteries. Dendrites form the surface of the cathode material during charging and discharging. There is a problem where .

Therefore, there is a need to research new electrolyte technologies that can simultaneously secure battery stability and performance.

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 intended to solve the above-mentioned problems, and the purpose of the present invention is to provide a flame-retardant gel electrolyte that can simultaneously secure the performance and stability of energy storage devices, including batteries.

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 provides a flame-retardant gel electrolyte comprising a compound represented by the following formula (1).

[Formula 1]

In Formula 1, n, m and l are each integers from 1 to 1,000, and at least one of A, B and C is -OCO(CF ₂ ) _x CF ₃ or -OCOR ¹ (CF ₂ ) _x CF ₃ , and among A, B and C -OCO(CF ₂ ) _x CF ₃ or ^{-OCOR 1} _{( CF 2} ^{) _ _ _} It is a substituted C _1-10 alkyl group, x is an integer of 1 to 10, and R ² is a substituted or unsubstituted C _1-10 alkyl group.

According to one embodiment, A is -OH, -R ² OH or -OR ² OH, B is -CN, -R ² CN or -OR ² CN, and C is -OCO (CF ₂ ) _x CF ₃ or -OCOR ¹ (CF ₂ ) _x CF ₃ .

According to one embodiment, C is -OCO(CH ₂ ) _y (CF ₂ ) _x CF ₃ , and the compound represented by Formula 1 is a compound represented by Formula 2 as shown in Scheme 1 below. It may be manufactured by reacting with a compound represented by Formula 3.

[Scheme 1]

[Formula 2]

[Formula 3]

n, m and l are each integers from 1 to 1,000, and A and B are each OH, -CN, -R ² OH, -R ² CN, -OR ² OH or -OR ² CN, and , R ² is a substituted or unsubstituted C _1-10 alkyl group, x is an integer of 1 to 10, and y is an integer of 0 to 10.

According to one embodiment, the molar ratio of the compound represented by Formula 2 to the compound represented by Formula 3 may be 1:0.5 to 1:2.

According to one embodiment, the compound represented by Formula 1 may be gelled through a cross-linking reaction in which they cross-link each other in an electrolyte solution.

According to one embodiment, the crosslinking reaction may be performed at a temperature of 40°C to 80°C.

According to one embodiment, the compound represented by Formula 1 may be included in an amount of 2 to 5 parts by weight based on 100 parts by weight of the electrolyte solution.

According to one embodiment, the electrolyte solution may include a lithium salt and an organic solvent.

According to one embodiment, the lithium salt is LiPF ₆ , LiClO ₄ , LiBF ₄ , LiFSI, LiTFSI, LiSO ₃ CF ₃ , LiBOB, LiFOB, 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 contains one or more, and the concentration of the lithium salt may be 0.5 M to 3 M in the electrolyte solution.

According to one embodiment, the organic solvent is dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), and methylpropyl carbonate (MPC). , ethylpropyl carbonate (EPC), ethylmethyl carbonate (EMC), ethylene carbonate (EC), propylene carbonate (PC), and butylene carbonate (BC). It may include one or more selected from the group.

According to one embodiment, the flame-retardant gel electrolyte may be gelled inside the battery.

According to one embodiment, the flame-retardant gel electrolyte forms a solid electrolyte intermediate (SEI) layer on the surface of the negative electrode of a lithium secondary battery, and the solid electrolyte intermediate (SEI) layer may include LiF.

Another aspect of the present invention is an anode; A cathode containing at least one selected from the group consisting of graphite, silicon (Si), germanium (Ge), tin (Sn), and antimony (Sb); And it provides a lithium secondary battery comprising the flame-retardant gel electrolyte of claim 1.

According to one embodiment, the lithium secondary battery may have a capacity retention rate of 85% or more calculated by the following equation.

[Equation]

Capacity maintenance rate (%) = [600 ^th cycle discharge capacity / 1 ^st cycle discharge capacity] × 100.

Another aspect of the present invention provides an energy storage device comprising the flame-retardant gel electrolyte.

The flame-retardant gel electrolyte according to the present invention has the effect of ensuring the stability of the energy storage device to which it is applied by having characteristics that do not burn, and has the advantage of being able to be gelled in situ inside the battery. Additionally, it has the effect of improving the lifespan characteristics of lithium secondary batteries compared to existing liquid electrolytes.

The lithium secondary battery according to the present invention contains a flame-retardant gel electrolyte, so there is no risk of explosion or fire, and the lifespan characteristics are improved by forming an SEI layer on the negative electrode to suppress side reactions with the electrolyte and prevent deterioration of the negative electrode. there is.

The energy storage device according to the present invention has the effect of ensuring both stability and performance by including a flame-retardant gel electrolyte.

Figure 1 is a photograph showing the flame retardancy test results of the gel electrolyte of Example 1 and the conventional PVA-CN gel electrolyte.
Figure 2 is a graph showing the specific capacity (mAhg ^-1 ) and voltage (V) according to charging and discharging of the lithium secondary battery using the gel electrolyte of Example 1 and the lithium secondary battery using the liquid electrolyte.
Figure 3 is a graph showing the specific capacity (mAhg ^-1 ) and coulombic efficiency (%) according to charge and discharge cycle of the lithium secondary battery using the gel electrolyte of Example 1 and the lithium secondary battery using the liquid electrolyte.

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 provides a flame-retardant gel electrolyte comprising a compound represented by the following formula (1).

[Formula 1]

In Formula 1, n, m and l are each integers from 1 to 1,000, and at least one of A, B and C is -OCO(CF ₂ ) _x CF ₃ or -OCOR ¹ (CF ₂ ) _x CF ₃ , and among A, B and C -OCO(CF ₂ ) _x CF ₃ or ^{-OCOR 1} _{( CF 2} ^{) _ _ _} It is a substituted C _1-10 alkyl group, x is an integer of 1 to 10, and R ² is a substituted or unsubstituted C _1-10 alkyl group.

The flame-retardant gel electrolyte according to the present invention has improved flame retardancy by including a polymer into which a perfluoroalkylate group is introduced.

The n, m, and l may each be selected depending on the number average molecular weight of the compound. For example, n, m, and l are each 2 or more; over 10; 20 or more; 30 or more; over 50; or 100 or more; 200 or more; 300 or more; 500 or more; Or it may be an integer greater than 800.

According to one embodiment, A is -OH, -R ² OH or -OR ² OH, B is -CN, -R ² CN or -OR ² CN, and C is -OCO (CF ₂ ) _x CF ₃ or -OCOR ¹ (CF ₂ ) _x CF ₃ .

At this time, n, m, and l may each be selected according to the number average molecular weight of the compound. Preferably, n may be an integer of 10 to 50, m may be an integer of 800 to 900, and l may be an integer of 550 to 590.

The range of n may be a range so that the compound represented by Formula 1 has hydrophilicity and forms hydrogen bonds inside the gel electrolyte, and the range of m may be a range in which crosslinking of each polymer chain can be optimized. It can be. In addition, the range of l may be a range that can secure the flame retardancy of the gel electrolyte and effectively form an SEI layer on the surface of the negative electrode of a lithium secondary battery.

Therefore, when n, m, and l are outside the above range, gelation may be difficult or solubility problems may occur, and flame retardancy and lifespan characteristics may be slightly improved.

According to one embodiment, A may be -OH, B may be -OCH ₂ CH ₂ CN, and C may be -OCOCF ₂ CF ₂ CF ₃ . At this time, the compound represented by Formula 1 may be represented by the following chemical structure.

[Formula 1-1]

According to one embodiment, the flame retardant gel electrolyte may be extinguished within 0.5 seconds after being ignited.

The flame-retardant gel electrolyte has the characteristic that even if it catches fire, the fire does not remain and can be extinguished within 0.5 seconds, preferably within 0.1 second, and more preferably within 0.01 second.

According to one embodiment, C is -OCO(CH ₂ ) _y (CF ₂ ) _x CF ₃ , and the compound represented by Formula 1 is a compound represented by Formula 2 as shown in Scheme 1 below. It may be manufactured by reacting with a compound represented by Formula 3.

[Scheme 1]

[Formula 2]

[Formula 3]

n, m and l are each integers from 1 to 1,000, and A and B are each OH, -CN, -R ² OH, -R ² CN, -OR ² OH or -OR ² CN, and , R ² is a substituted or unsubstituted C _1-10 alkyl group, x is an integer of 1 to 10, and y is an integer of 0 to 10.

Preferably, n may be an integer of 10 to 50, m may be an integer of 800 to 900, and l may be an integer of 550 to 590.

The x may be an integer from 1 to 10, which may be a range for optimizing the flame retardancy of the gel electrolyte and the performance of a lithium secondary battery to which it is applied.

If x is below the above range, the flame retardancy improvement effect may be minimal, and if x is above the above range, side reactions may increase in the electrolyte, which may deteriorate the performance of the lithium secondary battery.

According to one embodiment, the molar ratio of the compound represented by Formula 2 to the compound represented by Formula 3 may be 1:0.5 to 1:2.

The molar ratio of the compound represented by Formula 2 to the compound represented by Formula 3 may preferably be 1:0.8 to 1:2 or 1:1 to 1:2, and more preferably 1:1.2 to 1:2. It may be 1:2, and more preferably, it may be 1:1.5 to 1:2.

If the ratio of the compound represented by Formula 3 is less than the above range based on the case where the ratio of the compound represented by Formula 2 is 1, the lifespan characteristics of the battery to which the flame retardant gel electrolyte is applied may decrease, The effect of improving flame retardancy may be reduced, which may cause a problem in that the flame retardancy is no different from that of a general gel electrolyte.

For example, the solid electrolyte intermediate phase layer is not sufficiently formed at the negative electrode interface of the lithium secondary battery to which the flame-retardant gel electrolyte is applied, so the stability of the negative electrode interface may be reduced, side reactions with the electrolyte may occur, and insertion of lithium ions into the negative electrode may occur. The degree may decrease.

On the other hand, based on the case where the ratio of the compound represented by Formula 2 is 1, if the ratio of the compound represented by Formula 3 exceeds the above range, a problem may occur in which impurities increase during the synthesis process, It may be difficult to gel the flame-retardant gel electrolyte, and as the fluorine content relatively increases, side reactions in the electrolyte may increase, thereby significantly lowering the capacity retention rate.

In other words, the content of fluorine (F) contained in the compound represented by Formula 3 may be a key factor in determining the flame retardancy and battery performance of a lithium secondary battery or energy storage device using a gel electrolyte.

According to one embodiment, the compound represented by Formula 1 may be gelled through a cross-linking reaction in which they cross-link each other in an electrolyte solution.

That is, the compounds represented by Formula 1 can be initiated by a lithium salt in the electrolyte solution without adding a separate cross-linking agent, and can be gelled by cross-linking each other. Therefore, there is an advantage that it can be gelled in situ after addition to the electrolyte in the battery.

According to one embodiment, the crosslinking reaction may be performed at a temperature of 40°C to 80°C. Preferably, the crosslinking reaction may be performed at a temperature of 50°C to 70°C.

If the temperature during the crosslinking reaction is below the above range, the crosslinking reaction may not proceed sufficiently or the crosslinking reaction speed may be slow, and if it exceeds the above range, in situ gelation within the battery may be difficult or the performance of the battery may be impaired as a high temperature process is required. Deterioration may occur.

According to one embodiment, the compound represented by Formula 1 may be included in an amount of 2 to 5 parts by weight based on 100 parts by weight of the electrolyte solution.

If, based on the weight of the electrolyte solution, the content of the compound represented by Formula 1 is less than the above range, gelation through crosslinking reaction may be difficult or the flame retardancy obtained through gelation may be reduced, and if the content is less than the above range, If it exceeds , problems may occur in battery performance, such as a sharp drop in ionic conductivity and reduced lifespan characteristics.

According to one embodiment, the electrolyte solution may include a lithium salt and an organic solvent.

According to one embodiment, the lithium salt is LiPF ₆ , LiClO ₄ , LiBF ₄ , LiFSI, LiTFSI, LiSO ₃ CF ₃ , LiBOB, LiFOB, 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 contains one or more, and the concentration of the lithium salt may be 0.5 M to 3 M in the electrolyte solution.

The concentration of the lithium salt may preferably be 0.8 M to 1.5 M in the electrolyte solution, and more preferably 0.8 M to 1.2 M in the electrolyte solution.

If the concentration of the lithium salt is less than the above range, the crosslinking reaction of the compound represented by Formula 1 does not proceed sufficiently, which may cause a problem of gelation, and the flame retardancy of the gel electrolyte may decrease.

On the other hand, if the concentration of the lithium salt exceeds the above range, problems such as reduced ionic conductivity and reduced battery life characteristics may occur due to high viscosity.

According to one embodiment, the organic solvent is dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), and methylpropyl carbonate (MPC). , ethylpropyl carbonate (EPC), ethylmethyl carbonate (EMC), ethylene carbonate (EC), propylene carbonate (PC), and butylene carbonate (BC). It may include one or more selected from the group.

According to one embodiment, the organic solvent may include two or more types of carbonate-based solvents, and the carbonate-based solvent has excellent electrochemical stability, oxidation resistance, and reduction resistance, so that decomposition is minimized during the charging and discharging process of the battery. There are advantages to this.

For example, the organic solvent may include a first solvent containing ethylene carbonate (EC) and a second solvent containing ethylmethyl carbonate (EMC).

The volume ratio of the first solvent and the second solvent may be 1:1 to 1:10, preferably 1:1 to 1:5, and more preferably 1:2 to 1:5. It may be 1:3.

According to one embodiment, the flame-retardant gel electrolyte may be gelled inside the battery.

In other words, it has the characteristic of being able to gel in situ inside the battery, and this is because gelation can be initiated even when a small amount of the compound represented by Chemical Formula 1 is added to an electrolyte solution containing a lithium salt.

According to one embodiment, the flame-retardant gel electrolyte forms a solid electrolyte intermediate (SEI) layer on the surface of the negative electrode of a lithium secondary battery, and the solid electrolyte intermediate (SEI) layer may include LiF.

The solid electrolyte intermediate layer may be formed on the surface of the cathode when fluorine (F) contained in the flame-retardant gel electrolyte is decomposed, and includes a LiF component. By preventing side reactions between the negative electrode and the electrolyte, this prevents deterioration of the negative electrode and ultimately improves the lifespan of the lithium secondary battery.

The upper middle layer containing LiF can improve the mobility of lithium ions at the cathode interface, thereby improving the capacity retention rate of a lithium secondary battery.

Another aspect of the present invention is an anode; A cathode containing at least one selected from the group consisting of graphite, silicon (Si), germanium (Ge), tin (Sn), and antimony (Sb); And it provides a lithium secondary battery comprising the flame-retardant gel electrolyte of claim 1.

The lithium secondary battery according to the present invention contains a flame-retardant gel electrolyte, so there is no risk of explosion or fire, and the lifespan characteristics are improved by forming an SEI layer on the negative electrode to suppress side reactions with the electrolyte and prevent deterioration of the negative electrode. there is.

According to one embodiment, the lithium secondary battery may have a capacity retention rate of 85% or more calculated by the following equation.

[Equation]

Capacity maintenance rate (%) = [600 ^th cycle discharge capacity / 1 ^st cycle discharge capacity] × 100.

That is, the lithium secondary battery according to the present invention exhibits excellent lifespan characteristics, and in particular, has improved lifespan characteristics compared to a lithium secondary battery using a conventional liquid electrolyte.

Another aspect of the present invention provides an energy storage device comprising the flame-retardant gel electrolyte.

Examples of the energy storage device include, but are not limited to, lithium secondary batteries, capacitors, and solar cells.

The flame-retardant gel electrolyte can be applied to all devices in the electrochemical device field.

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 1> Preparation of gel electrolyte

1. Synthesis of polymer compounds

PVA-CN (3 g, 0.01925 mol) and 87.5 ml of DMF were added to a 250 ml round flask and stirred. Perfluorobutanoic acid (3,3 g, 0.0288 mol) and DCC (5.94 g, 0.0288 mol) were added to the mixed solution, and the round flask was immersed in ice water. DMAP (0.15 g, 0.0012 mol) was dissolved in 12 ml of DMF and then slowly added to the round flask. After 10 minutes, the ice water was removed and reacted at room temperature for 67 hours. After the reaction was completed, the precipitate was filtered, the remaining polymer solution was precipitated in distilled water, and the polymer was dried in a vacuum oven at 80 degrees.

The polymer compound synthesis process is shown in Scheme 2.

[Scheme 2]

2. Gel electrolyte preparation

Next, 0.03 g of the synthesized polymer was dissolved in 1.47 g of electrolyte solution (1 M LiPF ₆ in EC/EMC (3/7)), and then a crosslinking reaction was performed at a temperature of 60 °C to obtain a gelled electrolyte.

The molar ratio of reaction compounds during polymer synthesis is shown in Table 1.

Reactive Compound 2
(n= 10 ~ 50, m = 800 ~ 900) Reactive Compound 3 Example 1 One 1.5

<Experimental Example 1> Flame retardancy test

In order to confirm the flame retardancy of the gel electrolyte prepared in Example 1, the gel electrolyte of Example 1 and the conventionally used PVA-CN gel electrolyte were ignited and observed to see whether they burned.

Figure 1 is a photograph showing the flame retardancy test results of the gel electrolyte of Example 1 and the conventional PVA-CN gel electrolyte.

Referring to Figure 1, in the case of the PVA-CN gel electrolyte, it is confirmed that it is still burning even 5 seconds after ignition, whereas in the case of the gel electrolyte according to the present invention, the fire goes out within 0.5 seconds and does not burn. You can confirm that you have .

<Experimental Example 2> Performance evaluation of lithium secondary battery using flame-retardant gel electrolyte

Performance of the lithium secondary battery with NCM622/Gr full cell configuration using the gel electrolyte of Example 1 and the lithium secondary battery with NCM622/Gr full cell configuration using conventional liquid electrolyte (1 M LiPF6 in EC/EMC (3/7)) To compare and analyze, a charging and discharging experiment of a coin-type battery was conducted.

Here, the NCM622 electrode was manufactured as a 2.5 mAh/cm ² grade with a mass ratio of NCM622 : PVdF : Super P = 94 : 3 : 3. Additionally, the Gr electrode was manufactured with a mass ratio of Gr:SBR-CMC:Super P = 94:3:3.

As a comparative example, a coin-type battery was made with a liquid electrolyte, went through a chemical conversion step of 0.1 C-rate, gelled, and then charged and discharged.

At this time, the performance of the batteries was compared with a driving voltage range of 3 - 4.2 V, a charge/discharge rate of 1C-rate (165 mA/g), and a driving temperature of 25°C.

Figure 2 is a graph showing the specific capacity (mAhg ^-1 ) and voltage (V) according to charging and discharging of the lithium secondary battery using the gel electrolyte of Example 1 and the lithium secondary battery using the liquid electrolyte.

Figure 2a is a graph showing the specific capacity (mAhg ^-1 ) and voltage (V) according to charging and discharging of a lithium secondary battery using a liquid electrolyte, and Figure 2b is a graph showing the charging of a lithium secondary battery using the gel electrolyte of Example 1. This is a graph showing the specific capacity (mAhg ^-1 ) and voltage (V) according to discharge.

Figure 3 is a graph showing the specific capacity (mAhg ^-1 ) and coulombic efficiency (%) according to charge and discharge cycle of the lithium secondary battery using the gel electrolyte of Example 1 and the lithium secondary battery using the liquid electrolyte.

Referring to Figures 2 and 3, the lithium secondary battery using a liquid electrolyte has a capacity retention rate of 80.4% after 600 cycles, while the capacity retention rate of 85.5% after 600 cycles when using the gel electrolyte of Example 1 according to the present invention You can see that it represents the retention rate.

Through this, it can be understood that the gel electrolyte according to the present invention improves the lifespan characteristics of a lithium secondary battery compared to the case of using a conventional liquid electrolyte.

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)

Containing a compound represented by Formula 1 below,
Flame retardant gel electrolyte:
[Formula 1]

In Formula 1, n, m, and l are each integers from 1 to 1,000,
One or more of A, B and C is -OCO(CF ₂ ) _x CF ₃ ;
Among A, B and C, the remainder other than -OCO(CF ₂ ) _x CF ₃ is -OH, -CN, -R ² OH, -R ² CN, -OR ² OH or -OR ² CN,
The x is an integer from 1 to 10,
Said R ² is an unsubstituted C _1-10 alkyl group.
According to paragraph 1,
The A is -OH, -R ² OH or -OR ² OH,
The B is -CN, -R ² CN or -OR ² CN,
The C is -OCO(CF ₂ ) _x CF ₃ ,
Flame retardant gel electrolyte.
According to paragraph 1,
The C is -OCO(CF ₂ ) _x CF ₃ ,
The compound represented by Formula 1 is,
As shown in Scheme 1 below, it is prepared by reacting a compound represented by Formula 2 below with a compound represented by Formula 3 below,
Flame retardant gel electrolyte:
[Scheme 1]

[Formula 2]

[Formula 3]

The n, m and l are each integers from 1 to 1,000,
The A and B are each OH, -CN, -R ² OH, -R ² CN, -OR ² OH or -OR ² CN,
R ² is an unsubstituted C _1-10 alkyl group,
The x is an integer from 1 to 10.
According to paragraph 3,
The molar ratio of the compound represented by Formula 2: the compound represented by Formula 3 is,
1:0.5 to 1:2,
Flame retardant gel electrolyte.
According to paragraph 1,
The compound represented by Formula 1 is,
It is gelled through a cross-linking reaction that cross-links each other in the electrolyte solution.
Flame retardant gel electrolyte.
According to clause 5,
The crosslinking reaction is,
which is carried out at a temperature of 40 ℃ to 80 ℃,
Flame retardant gel electrolyte.
According to clause 5,
For 100 parts by weight of the electrolyte,
The compound represented by Formula 1 is contained in an amount of 2 to 5 parts by weight,
Flame retardant gel electrolyte.
According to clause 5,
The electrolyte is,
Containing a lithium salt and an organic solvent,
Flame retardant gel electrolyte.
According to clause 8,
The lithium salt is LiPF ₆ , LiClO ₄ , LiBF ₄ , LiFSI, LiTFSI, LiSO ₃ CF ₃ , LiBOB, LiFOB, 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 and includes one or more selected from the group consisting of ,
The concentration of the lithium salt is 0.5 M to 3 M in the electrolyte solution,
Flame retardant gel electrolyte.
According to clause 8,
The organic solvent is,
Dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methylpropyl carbonate (MPC), ethylpropyl carbonate (EPC), Containing at least one selected from the group consisting of ethylmethyl carbonate (EMC), ethylene carbonate (EC), propylene carbonate (PC), and butylene carbonate (BC). ,
Flame retardant gel electrolyte.
According to paragraph 1,
The flame retardant gel electrolyte is,
which gels inside the battery,
Flame retardant gel electrolyte.
According to paragraph 1,
The flame retardant gel electrolyte is,
Forming a solid electrolyte intermediate (SEI) layer on the surface of the negative electrode of a lithium secondary battery,
The solid electrolyte intermediate phase (SEI) layer includes LiF,
Flame retardant gel electrolyte.
anode;
A cathode containing at least one selected from the group consisting of graphite, silicon (Si), germanium (Ge), tin (Sn), and antimony (Sb); and
Containing the flame retardant gel electrolyte of claim 1,
Lithium secondary battery.
According to clause 13,
The capacity maintenance rate calculated by the following equation is 85% or more,
Lithium secondary battery:
[Equation]
Capacity maintenance rate (%) = [600 ^th cycle discharge capacity / 1 ^st cycle discharge capacity] × 100.
Comprising the flame retardant gel electrolyte of claim 1,
Energy storage device.