1. An acid inhibitor for lithium ion battery electrolyte is characterized in that the acid inhibitor comprises at least one of a compound A or a compound B with the structure shown as follows:

2. a lithium ion battery electrolyte comprising lithium hexafluorophosphate, an organic solvent and the acid inhibitor of claim 1.

3. The lithium ion battery electrolyte of claim 2, wherein the acid inhibitor is present in the electrolyte in an amount of 0.005 wt% to 0.05 wt%.

4. The lithium ion battery electrolyte of claim 3, wherein the acid inhibitor is present in the electrolyte in an amount of 0.01 to 0.03 wt%.

5. The lithium ion battery electrolyte of claim 2, wherein the concentration of the lithium hexafluorophosphate in the electrolyte is 0.8 to 1.2 mol/L.

6. The lithium ion battery electrolyte of claim 2, wherein the organic solvent comprises at least one of a carbonate, a carboxylate, and a fluorocarboxylate.

7. The lithium ion battery electrolyte of claim 6, wherein the carbonate comprises at least one of dimethyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, ethyl methyl carbonate, butylene carbonate, or propyl methyl carbonate.

8. The lithium ion battery electrolyte of claim 6, wherein the carboxylic acid ester comprises at least one of ethyl formate, ethyl acetate, propyl acetate, butyl acetate, propyl propionate, butyl propionate, ethyl butyrate, methyl formate, or ethyl propionate.

9. The lithium ion battery electrolyte of claim 6, wherein the fluorocarboxylic acid ester comprises at least one of ethylfluorocarboxylate, ethylfluoroacetate, propylfluoroacetate, butyl fluoroacetate, ethylfluoropropionate, propylfluoropropionate, butyl fluoropropionate, ethylfluorobutyrate, or methylfluorocarboxylate.

10. A lithium ion battery, comprising:

the positive electrode comprises a positive electrode current collector and a positive electrode active material layer which is arranged on the surface of the positive electrode current collector and contains a positive electrode active material;

the negative electrode comprises a negative electrode current collector and a negative electrode active material layer which is arranged on the surface of the negative electrode current collector and contains a negative electrode active material;

a separator provided between the positive electrode and the negative electrode; and

the electrolyte of any one of claims 2 to 9.

Background

A lithium ion battery is a type of secondary battery (rechargeable battery) that relies primarily on lithium ions (Li)⁺) Moving between the positive and negative electrodes to work. During charging of lithium ion batteries, Li⁺The lithium ion is extracted from the positive electrode and is inserted into the negative electrode through the electrolyte, so that the negative electrode is in a lithium-rich state, the conversion of electric energy into chemical energy is realized, and the reverse process is just realized in the discharge process。

The lithium ion battery has the advantages of higher working voltage, high energy density, environmental friendliness and the like, and is widely applied to the fields of 3C consumer batteries, power batteries, energy storage batteries and the like. In the lithium ion battery, the electrolyte is the only material in contact with the anode, the cathode and the diaphragm, and plays an important role in the specific capacity, the working temperature range, the cycle efficiency, the safety performance and the like of the battery.

The electrolyte of commercial lithium ion battery is generally lithium salt LiPF₆Dissolving in a mixed solvent of cyclic and linear carbonates to obtain a solution of 1 mol/L. However, the organic solvent inevitably contains a small amount of moisture, and the electrolyte is extremely sensitive to the presence of moisture, mainly due to LiPF contained therein₆Is highly sensitive to water, and under the condition that the water content is extremely low (< 10ppm), the LiPF₆All react with the catalyst to produce an acidic compound such as Hydrogen Fluoride (HF). HF is very undesirable for Li-ion batteries, has very high corrosion and dissolves Solid Electrolyte Interface (SEI) films, e.g., Li in the SEI film₂CO₃LiF is generated by reaction, so that the stability and compactness of the SEI film are damaged, and the impedance of an electrode interface is increased. In addition, HF reacts with the positive electrode material of the battery, causing elution of metal ions in the positive electrode material and destruction of the material structure.

In addition, LiPF₆Also can decompose by itself to produce a trace amount of PF₅. Thermal failure studies showed that at PF₅Under the action of the organic silicon compound, the SEI film can be decomposed within a medium temperature range of 60-135 ℃, so that the thickening of the SEI film is accelerated, and the polarization degree of a battery is increased. In addition, the decomposition reaction of SEI film also includes acid catalyzed reaction, for example, strong Lewis acid PF₅Can catalyze Li₂CO₃The lithium alkylcarbonate decomposes to generate a gas or a soluble organic substance, thereby making the SEI film porous.

Thus, it can be seen that PF₅And HF have great damage to the battery performance, however, no particularly effective means for effectively inhibiting PF in electrolyte exists at present₅And reduction of activity ofThe content of HF.

Disclosure of Invention

Aiming at the defects in the prior art, the application provides an acid inhibitor for lithium ion battery electrolyte, the electrolyte and a lithium ion battery, which can reduce the content of hydrofluoric acid in the electrolyte and inhibit PF in the electrolyte₅Activity of (2).

In order to achieve the above object, in a first aspect, the present application provides an acid inhibitor for an electrolyte of a lithium ion battery, the acid inhibitor comprising at least one of a compound a or a compound B having a structure shown as follows:

in a second aspect, the present application provides a lithium ion battery electrolyte comprising lithium hexafluorophosphate (LiPF)₆) An organic solvent and an acid inhibitor according to claim 1.

In combination with the second aspect, in a possible embodiment, the acid inhibitor is present in the electrolyte in an amount of 0.005 wt% to 0.05 wt%.

In combination with the second aspect, in a possible embodiment, the acid inhibitor is present in the electrolyte in an amount of 0.01 wt% to 0.03 wt%.

In one possible embodiment in combination with the second aspect, the concentration of the lithium hexafluorophosphate in the electrolyte solution is 0.8mol/L to 1.2 mol/L.

In one possible embodiment in combination with the second aspect, the organic solvent includes at least one of a carbonate, a carboxylate, and a fluorocarboxylate.

In combination with the second aspect, in one possible embodiment, the carbonate includes at least one of dimethyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, ethyl methyl carbonate, butylene carbonate, or propyl methyl carbonate.

In one possible embodiment in combination with the second aspect, the carboxylic acid ester includes at least one of ethyl formate, ethyl acetate, propyl acetate, butyl acetate, propyl propionate, butyl propionate, ethyl butyrate, methyl formate, or ethyl propionate.

In one possible embodiment in combination with the second aspect, the fluorocarboxylic acid ester includes at least one of ethylfluorocarboxylate, ethylfluoroacetate, propylfluoroacetate, butyl fluoroacetate, ethylfluoropropionate, propylfluoropropionate, butyl fluoropropionate, ethylfluorobutyrate, or methylfluorocarboxylate.

In a third aspect, the present application provides a lithium ion battery comprising:

the positive electrode comprises a positive electrode current collector and a positive electrode active material layer which is arranged on the surface of the positive electrode current collector and contains a positive electrode active material;

the negative electrode comprises a negative electrode current collector and a negative electrode active material layer which is arranged on the surface of the negative electrode current collector and contains a negative electrode active material;

a separator provided between the positive electrode and the negative electrode; and

the electrolyte according to the second aspect above.

The technical scheme that this application provided compares and has following beneficial effect at least in prior art:

the acid inhibitor can react with water to reduce the water content in the electrolyte, thereby reducing LiPF₆The amount of HF formed by reaction with water; in addition, the acid inhibitor can react with HF, so that the amount of the generated HF in the electrolyte is further reduced; in addition, the antacid can be mixed with Lewis acid PF₅Coordination complexation, PF reduction₅Activity of (2).

Compared with the electrolyte without the acid inhibitor, the electrolyte containing the acid inhibitor can effectively reduce the content of water and HF in the electrolyte after the acid inhibitor is added, sealed and placed.

According to the lithium ion battery provided by the application, the acid inhibitor is added into the electrolyte, so that the amount of HF generated in the electrolyte can be reduced, the side reaction of the lithium ion battery is reduced, the stability and compactness of an SEI (solid electrolyte interphase) film on the surface of a pole piece are improved, the impedance of an electrode interface is reduced, and the cycling stability of the battery is improved.

Detailed Description

In order to make the present application more clearly understood by those skilled in the art, the present application will be described in further detail with reference to the following examples, but it should be understood that the following examples are only preferred embodiments of the present application, and the scope of the present application is defined by the scope of the claims.

In a first aspect, the present application provides an acid inhibitor for an electrolyte of a lithium ion battery, the acid inhibitor comprising at least one of a compound a or a compound B having a structure shown as follows:

the inventors found that in the presence of a lithium salt LiPF₆In the lithium ion battery electrolyte of (1), LiPF₆The reaction process for the reaction with water to form HF is shown below:

LiPF₆→LiF+PF₅

H₂O+PF₅→POF₃+2HF

as can be seen from the above reaction formula, LiPF₆First decompose itself to produce a trace amount of PF₅，PF₅Belongs to strong Lewis acid, has strong chemical activity and is easy to react with water to generate HF, so the LiPF₆The reaction with water is mainly its own decomposition product PF₅React with water to form HF.

Therefore, based on the above situation, the present application slave controls the PF₅Starting from the key point of the activity and amount of (a), effective inhibition of PF in the electrolyte is achieved by adding an acid inhibitor (compound A and/or compound B)₅Activity and reduction of the content of HF.

In the technical scheme of the application, the acid inhibitor comprises at least one of a compound A (bis (trimethylsilyl) trifluoroacetamide) or a compound B (5-methyl-3- (trimethylsilyl) oxazolidin-2-one), and the acid inhibitor can be firstly reacted with H₂O reaction, reducing the water content in the electrolyte, thereby reducing LiPF from the source₆PF as a decomposition product of₅The amount of HF formed by reaction with water; secondly, compounds A and B both contain Trimethylsilyl (TMS) groups that can react with HF, effectively trapping F of HF^-Thereby reducing the amount of HF generated in the electrolyte, and the nitrogen atoms connected with TMS in the compounds A and B are also connected with a strong electron-withdrawing group (trifluoromethyl carbonyl or oxycarbonyl), thereby being more beneficial to the fracture of Si-N bonds, promoting the release of TMS and further increasing the F-pair^-The captured force is used for further removing HF; thirdly, the N atoms contained in the compound A and the compound B have lone pair electrons, have stronger coordination complexing ability and can be matched with the PF of the Lewis acid₅Coordination complexation, PF reduction₅Reactivity with water and thus also the production of HF can be reduced.

Therefore, the acid inhibitor for the lithium ion battery electrolyte can play a role in three aspects of water removal, acid absorption, activity inhibition and the like, greatly inhibits the generation of HF in the lithium ion battery electrolyte, further reduces the damage to battery components such as an SEI film and a positive electrode material, effectively maintains the charge and discharge performance of the lithium ion battery, and improves the cycle life of the lithium ion battery.

In a second aspect, the present application provides a lithium ion battery electrolyte comprising lithium hexafluorophosphate (LiPF)₆) An organic solvent and the above acid inhibitor.

In the prior art, organic solvents and the like inevitably contain trace moisture and moisture introduced in the preparation process, so that the lithium ion battery electrolyte contains moisture and is mixed with LiPF₆The reaction produces HF. In order to solve the problem, a specific acid inhibitor is added into the lithium ion battery electrolyte, so that the content of water and HF in the electrolyte can be effectively reduced after the electrolyte is placed in a sealed mode compared with the electrolyte which is not added.

Further, in the lithium ion battery electrolyte, the mass content of the acid inhibitor in the electrolyte is 0.005 wt% -0.05 wt%, namely 50-500 ppm. The mass content of the acid inhibitor may be specifically 0.005 wt%, 0.006 wt%, 0.008 wt%, 0.01 wt%, 0.02 wt%, 0.03 wt%, 0.04 wt%, or 0.05 wt%, but it is not limited thereto, and may be other values within the above range.

At such a small amount, the acid inhibitor according to the present application can exhibit remarkable water removal, acid absorption, and activity inhibition effects. In view of the control of the initial water content of the electrolyte and the improvement of the water and acid removing effect in the actual industry, the acid inhibitor can be preferably contained in the electrolyte in an amount of 0.01 to 0.03 wt%, i.e., 100 to 300ppm by mass. Specifically, the water content of lithium ion battery electrolyte in actual industry is usually much less than 300ppm, in this case, adding 300ppm of acid inhibitor can fully exert sufficient effect, and when the adding amount of acid inhibitor is 300-500 ppm, the water and acid removing effect is still further improved, but the improvement range is slowed down.

Further, in the electrolyte for a lithium ion battery according to the present application, the concentration of the lithium hexafluorophosphate in the electrolyte may be 0.8mol/L to 1.2mol/L, specifically, 0.8mol/L, 0.9mol/L, 0.95mol/L, 1.0mol/L, 1.05mol/L, 1.1mol/L, 1.15mol/L, or 1.2mol/L, and the like, and may of course be other values within the above range. When the concentration of the hexafluorophosphoric acid is less than 0.8mol/L, the lithium ion concentration of the electrolyte is low, and the ionic conductivity is too low, resulting in the reduction of the rate capability and cycle performance of the battery. When the concentration of the hexafluorophosphoric acid is more than 1.2mol/L, the lithium salt may be difficult to dissolve, or crystallization may occur during low-temperature storage after dissolution, the viscosity of the electrolyte is too high, the conductivity of lithium ions is reduced, the use window of the electrolyte is narrow, the wettability is poor, and the electrochemical performance of the battery is affected. The concentration of the lithium hexafluorophosphate in the electrolyte is preferably 0.8mol/L to 1.0 mol/L.

Further, in the lithium ion battery electrolyte according to the present application, the organic solvent includes at least one of carbonate, carboxylate, and fluorocarboxylate. In the present application, the organic solvent may be various organic solvents commonly used in lithium ion battery electrolytes, and those skilled in the art may select the organic solvent according to actual needs. The acid inhibitor according to the present invention can be applied to various organic solvents described above, and the application range is very wide.

The carbonate may include at least one of dimethyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, ethyl methyl carbonate, butylene carbonate, or propyl methyl carbonate.

The carboxylic acid ester may include at least one of ethyl formate, ethyl acetate, propyl acetate, butyl acetate, propyl propionate, butyl propionate, ethyl butyrate, methyl formate, or ethyl propionate.

The fluorocarboxylic acid ester may include at least one of fluoroethyl formate, fluoroethyl acetate, fluoropropyl acetate, fluoroacetyl acetate, fluoropropyl propionate, fluorobutyl butyrate, or fluoromethyl formate.

Further, in the lithium ion battery electrolyte according to the present application, the electrolyte further includes an additive including at least one of fluoroethylene carbonate (FEC), 1, 3-Propane Sultone (PS), Vinylene Carbonate (VC), or nitrile compounds. The additive is added into the electrolyte, so that a stable electrolyte film is formed on the surface of the battery pole piece, and the cycle stability of the lithium ion battery is improved.

The application also provides an electrochemical device, which comprises a positive current collector and a positive active material layer which is arranged on the surface of the positive current collector and contains a positive active material;

the negative electrode comprises a negative electrode current collector and a negative electrode active material layer which is arranged on the surface of the negative electrode current collector and contains a negative electrode active material;

a separator provided between the positive electrode and the negative electrode;

and an electrolyte according to the above.

As an optional technical scheme, the positive electrode active material layer comprises a positive electrode active material, a binder and a conductive agent.

As an improvement of the electrochemical device, the positive active material is at least one selected from lithium cobaltate LiCoO2, lithium nickel manganese cobalt ternary material, lithium iron phosphate, lithium iron manganese phosphate and lithium manganate.

As an improvement of the electrochemical device of the present application, the negative electrode active material layer of the present application includes a negative electrode active material, a binder, and a conductive agent.

As a modification of the electrochemical device of the present application, the negative electrode active material is selected from at least one of lithium metal or lithium metal alloy compound, carbon material, graphite material, silicon material, or silicon oxide material.

The present application also provides an electronic device comprising the electrochemical device described above.

The lithium ion battery electrolyte acid inhibitor according to the application can react with water firstly, so that the water content in the electrolyte is reduced, and LiPF is reduced₆The amount of HF formed by reaction with water; secondly, the acid inhibitor can react with HF, so that the amount of the generated HF in the electrolyte is further reduced; thirdly, the antacid can also react with Lewis acid PF₅Coordination complexation, PF reduction₅Activity of (2).

In addition, compared with the electrolyte without the acid inhibitor, the lithium ion battery electrolyte containing the acid inhibitor can effectively reduce the content of water and HF in the electrolyte after being sealed and placed for a period of time, further reduces damage to battery components such as SEI films and cathode materials, effectively maintains the charge and discharge performance of the lithium ion battery, and improves the cycle life of the lithium ion battery.

In addition, each of the compounds used herein is commercially available or ordered, and can be commercially obtained on the market by those skilled in the art as needed.

The technical solution of the present application is exemplarily described below by specific embodiments:

< example >

Comparative example 1

A mixed solvent of Ethylene Carbonate (EC), Ethyl Methyl Carbonate (EMC) and dimethyl carbonate (BMC) in a weight ratio of 1:1:1 is used as an organic solvent of the lithium ion battery electrolyte, and Vinylene Carbonate (VC) and fluoroethylene carbonate (FEC) which are additives accounting for 2.5 wt% of the system are added into the mixed solvent. Mixing lithium hexafluorophosphate (LiPF)₆) Dissolved in the above system to prepare a solution having a concentration of 1.0mol/L, thereby obtaining a lithium ion battery electrolyte X.

Comparative example 2

To the lithium ion battery electrolyte X of comparative example 1, water was added so that the initial concentration of water was 0.01 wt% (100ppm), thereby obtaining a lithium ion battery electrolyte Y.

Comparative example 3

To the lithium ion battery electrolyte X of comparative example 1, water was added so that the initial concentration of water was 0.03 wt% (300ppm), thereby obtaining a lithium ion battery electrolyte Z.

Examples 1 to 1

A mixed solvent of Ethylene Carbonate (EC), Ethyl Methyl Carbonate (EMC) and dimethyl carbonate (BMC) in a weight ratio of 1:1:1 is used as an organic solvent of the lithium ion battery electrolyte, and Vinylene Carbonate (VC) and fluoroethylene carbonate (FEC) which are additives accounting for 2.5 wt% of the system are added into the mixed solvent. Mixing lithium hexafluorophosphate (LiPF)₆) Dissolved in the above system to prepare a solution having a concentration of 1.0mol/L, and the compound A of the present application was added as an acid inhibitor so that the mass content of the compound A was 0.005 wt% (50ppm), thereby obtaining a lithium ion battery electrolyte XA1 according to the present application.

Examples 1 to 2

A lithium ion battery electrolyte XA2 according to the present application was obtained in the same manner as in example 1-1, except that the compound A of the present application was added as an acid inhibitor so that the mass content of the compound A was 0.02 wt% (200 ppm).

Examples 1 to 3

A lithium ion battery electrolyte XA3 according to the present application was obtained in the same manner as in example 1-1, except that the compound a of the present application was added as an acid inhibitor so that the mass content of the compound a was 0.03 wt% (300 ppm).

Examples 1 to 4

A lithium ion battery electrolyte XA4 according to the present application was obtained in the same manner as in example 1-1, except that the compound a of the present application was added as an acid inhibitor so that the mass content of the compound a was 0.05 wt% (500 ppm).

Examples 1 to 5

A lithium ion battery electrolyte YA5 according to the present application was obtained in the same manner as in example 1-1, except that the compound a of the present application was added as an acid inhibitor so that the mass content of the compound a was 0.02 wt% (200ppm), and water was added so that the initial concentration of water was 0.01 wt% (100 ppm).

Examples 1 to 6

A lithium ion battery electrolyte YA6 according to the present application was obtained in the same manner as in example 1-1, except that the compound a of the present application was added as an acid inhibitor so that the mass content of the compound a was 0.03 wt% (300ppm), and water was added so that the initial concentration of water was 0.01 wt% (100 ppm).

Examples 1 to 7

A lithium ion battery electrolyte YA7 according to the present application was obtained in the same manner as in example 1-1, except that the compound a of the present application was added as an acid inhibitor so that the mass content of the compound a was 0.05 wt% (500ppm), and water was added so that the initial concentration of water was 0.01 wt% (100 ppm).

Examples 1 to 8

A lithium ion battery electrolyte ZA8 according to the present application was obtained in the same manner as in example 1-1, except that the compound a of the present application was added as an acid inhibitor so that the mass content of the compound a was 0.02 wt% (200ppm), and water was added so that the initial concentration of water was 0.03 wt% (300 ppm).

Examples 1 to 9

A lithium ion battery electrolyte ZA9 according to the present application was obtained in the same manner as in example 1-1, except that the compound a of the present application was added as an acid inhibitor so that the mass content of the compound a was 0.03 wt% (300ppm), and water was added so that the initial concentration of water was 0.03 wt% (300 ppm).

Examples 1 to 10

A lithium ion battery electrolyte ZA10 according to the present application was obtained in the same manner as in example 1-1, except that the compound a of the present application was added as an acid inhibitor so that the mass content of the compound a was 0.05 wt% (500ppm), and water was added so that the initial concentration of water was 0.03 wt% (300 ppm).

Example 2-1

A mixed solvent of Ethylene Carbonate (EC), Ethyl Methyl Carbonate (EMC) and dimethyl carbonate (BMC) in a weight ratio of 1:1:1 is used as an organic solvent of the lithium ion battery electrolyte, and Vinylene Carbonate (VC) and fluoroethylene carbonate (FEC) which are additives accounting for 2.5 wt% of the system are added into the mixed solvent. Mixing lithium hexafluorophosphate (LiPF)₆) Dissolved in the above system to prepare a solution having a concentration of 1.0mol/L, and the compound B of the present application was added as an acid inhibitor so that the mass content of the compound B was 0.005 wt% (50ppm), thereby obtaining a lithium ion battery electrolyte XB1 according to the present application.

Examples 2 to 2

Except that the compound B of the present application was added as an acid inhibitor so that the mass content of the compound B was 0.02 wt% (200ppm), a lithium ion battery electrolyte XB2 according to the present application was obtained in the same manner as in example 2-1.

Examples 2 to 3

Except that the compound B of the present application was added as an acid inhibitor so that the mass content of the compound B was 0.03 wt% (300ppm), a lithium ion battery electrolyte XB3 according to the present application was obtained in the same manner as in example 2-1.

Examples 2 to 4

Except that the compound B of the present application was added as an acid inhibitor so that the mass content of the compound B was 0.05 wt% (500ppm), a lithium ion battery electrolyte XB4 according to the present application was obtained in the same manner as in example 2-1.

Examples 2 to 5

A lithium-ion battery electrolyte YB5 according to the present application was obtained in the same manner as in example 2-1, except that the compound B of the present application was added as an acid inhibitor so that the mass content of the compound B was 0.02 wt% (200ppm), and water was added so that the initial concentration of water was 0.01 wt% (100 ppm).

Examples 2 to 6

A lithium-ion battery electrolyte YB6 according to the present application was obtained in the same manner as in example 2-1, except that the compound B of the present application was added as an acid inhibitor so that the mass content of the compound B was 0.03 wt% (300ppm), and water was added so that the initial concentration of water was 0.01 wt% (100 ppm).

Examples 2 to 7

A lithium-ion battery electrolyte YB7 according to the present application was obtained in the same manner as in example 2-1, except that the compound B of the present application was added as an acid inhibitor so that the mass content of the compound B was 0.05 wt% (500ppm), and water was added so that the initial concentration of water was 0.01 wt% (100 ppm).

Examples 2 to 8

A lithium ion battery electrolyte ZB8 according to the present application was obtained in the same manner as in example 2-1, except that the compound B of the present application was added as an acid inhibitor so that the mass content of the compound B was 0.02% by weight (200ppm), and water was added so that the initial concentration of water was 0.03% by weight (300 ppm).

Examples 2 to 9

A lithium ion battery electrolyte ZB9 according to the present application was obtained in the same manner as in example 2-1, except that the compound B of the present application was added as an acid inhibitor so that the mass content of the compound B was 0.03 wt% (300ppm), and water was added so that the initial concentration of water was 0.03 wt% (300 ppm).

Examples 2 to 10

A lithium ion battery electrolyte ZB10 according to the present application was obtained in the same manner as in example 2-1, except that the compound B of the present application was added as an acid inhibitor so that the mass content of the compound B was 0.05 wt% (500ppm), and water was added so that the initial concentration of water was 0.03 wt% (300 ppm).

In the above comparative examples and examples, the concentrations of the added water and/or the acid inhibitor according to the present application were very slight, and thus the addition thereof was made to the organic solvent and LiPF in the electrolyte system₆The influence of the content ratio of (A) is negligible.

The lithium ion battery electrolytes in the comparative examples and the examples were sealed and left standing at normal temperature for 1 day and 1 week, respectively, and H was measured₂The contents of O (wt%) and HF (wt%), the results of which are shown in Table 1 below.

[ Table 1]

As can be seen from table 1 above, the lithium ion battery electrolytes according to the examples of the present application contain the acid inhibitor compound a/B in a minute amount, but are still capable of significantly and continuously suppressing the contents of water and HF, as compared to comparative examples 1 to 3.

Specifically, as shown in comparative examples 1 to 3, in the presence of raw water in the electrolyte or after further addition of water, water reacts with LiPF₆The reaction takes place, the water content decreases after 1 week, the HF content gradually increases and this phenomenon increases with the initial water content in the electrolyte. In contrast, examples 1-1 to 1-10, in which the acid inhibitor compound a according to the present application was added, all of them had a significant effect of reducing the water content and the HF content after standing for 1 day and 1 week at the sealing normal temperature at different initial water contents of the electrolyte, and the effect was better as the acid inhibitor addition amount was increased. And along with the increase of the initial water content of the electrolyte, the addition amount of the acid inhibitor is also correspondingly increased to achieve better water and acid removing effects. Considering that the water and acid removing effect of the acid inhibitor is 0.05 wt% (500ppm) and the addition amount is 0.03 wt%The improvement of the effect is limited when the electrolyte is (300ppm), and in the practical application process, the initial water content of the electrolyte can be controlled below 0.03 wt%, so that the addition amount of the acid inhibitor is 0.03 wt% to meet the conventional production requirement.

In addition, examples 2-1 to 2-10, in which the acid inhibitor compound B according to the present application was added, have effects similar to those of examples 1-1 to 1-10, but the effect of compound A is more excellent than that of compound A, which is mainly due to the fact that the group (trifluoromethylcarbonyl) bonded to N in compound A has a stronger electron-withdrawing ability in relation to the bond energy of the Si-N bond, Si-N is more easily cleaved, and trimethylsilyl is more easily released to react with water and HF.

The above-described embodiments of the present application are only examples of the present application and should not be construed as limiting the present application, and those skilled in the art can make modifications without inventive contribution as required after reading the present specification, however, any modifications, equivalents, improvements, etc. within the spirit and principle of the present application should be included in the scope of the present application.