Silane-based additive, electrolyte containing said additive, and lithium-ion battery

Abstract

The present invention provides the use of a silane-based additive containing a carbon-carbon triple bond in an electrolyte to suppress gas generation in a cell, the use of a composite additive of the silane-based additive and a film-forming additive in an electrolyte, the use of a composite additive of the silane-based additive and a fluorine-containing lithium salt additive in an electrolyte, and an electrolyte and a lithium-ion battery containing the silane-based additive. The combined use of the silane-based additive and the film-forming additive, or the combined use of the silane-based additive and the fluorine-containing lithium salt additive, not only suppresses gas generation in a cell and improves the high-temperature storage characteristics of the battery, but also improves the stability of the battery in high-temperature cycles and room-temperature cycles.

Description

[Technical field]

[0001] The present invention relates to a lithium ion battery electrolyte, in particular, a silane-based additive containing a carbon-carbon triple bond, a composite additive of the silane-based additive and a film-forming additive, a composite additive of the silane-based additive and a fluorine-containing lithium salt-based additive, an electrolyte containing the silane-based additive, and a lithium ion battery. [Background technology]

[0002] High energy density is the trend in the development of lithium batteries, and the most common methods to improve energy density are to increase the operating voltage and the nickel content of the positive electrode material, but each method brings new challenges to the cycle characteristics and safety of the cell, so attention has been focused on the high-temperature cycle characteristics and high-temperature storage stability of the battery.

[0003] In order to improve the high-temperature storage characteristics of lithium-ion batteries, additives such as vinylene carbonate (VC), vinylethylene carbonate (VEC), 1,3-propane sultone (PS), 1-propene 1,3-sultone (PST), and tris(trimethylsilyl)borate (TMSB) are usually added to the electrolyte to improve the high-temperature characteristics. VC and VEC form an SEI film on the negative electrode, suppress side reactions between the electrolyte and the negative electrode, and improve the stability of the electrode during high-temperature storage. In addition to forming a film on the negative electrode, PS, PST, and TMSB can form a CEI-based protective film on the surface of high-nickel positive electrode materials, suppressing the elution of metal ions in the high-nickel positive electrode and the associated parasitic reactions, and playing a role in improving the high-temperature storage characteristics of lithium batteries with high-nickel positive electrode materials.

[0004] However, these additives have their drawbacks. VEC or VC has a large volume expansion (gas generation) after high-temperature storage of the battery in the high-voltage battery system, and is poor at suppressing the rate of increase in cell impedance. PS and sulfonate-based additives such as PST have a significant effect of suppressing cell gas generation, but their initial impedance and impedance increase rate are high, which is disadvantageous to the low-temperature characteristics and rate characteristics of the battery. More importantly, PS is a carcinogen and is registered on the Reach restricted substance list, and its use is increasingly restricted. Homologues or structural analogues such as PST or 1,4-butane sultone (BS) also have the same risk, and their use is not recommended. TMSB can improve the high-temperature properties of high-nickel material systems, but its effect of suppressing cell gas generation is insufficient and its effect of suppressing impedance increase is also poor.

[0005] Patent CN109888386A of Dongguan Shanshan Battery Materials Co., Ltd. discloses a chain sulfate ester compound M and a cyclic sulfonate ester compound N. The compound M is involved in the formation of a passivation film at the interface between the positive electrode and the negative electrode, improving high-temperature characteristics and suppressing gas generation in the battery, but has high impedance and poor cycle characteristics. The compound N can improve the cycle characteristics of the battery and adjust the impedance, but is unstable and has very strict requirements for the storage environment and use environment. The combined use of compound M and compound N can optimize the cycle characteristics and storage characteristics of the battery, but faces the instability of compound N.

[0006] Patent CN109309248A of Ningde Times discloses a composite additive of sulfate ester compound and phosphate ester compound, which can preferentially form a film on the surface of the positive electrode, prevent gas generation caused by the combination of HF with SEI film or CEI film, and at the same time effectively protect the electrode interface, reduce the loss of active lithium under high temperature conditions, and significantly improve the high temperature storage properties of the battery. However, the high temperature storage properties of this composite additive still need to be improved, and no mention is made of the improvement of high temperature cycle stability.

[0007] In summary, the conventional high temperature property improving additives not only need to improve the high temperature storage property, but also have a high impedance in most of the interface protective film, and the impedance increase rate is also high, which deteriorates the rate property, low temperature property and long-term cycle stability of the battery. Therefore, it is currently one of the technical difficulties to improve the high temperature storage property while simultaneously achieving the high temperature cycle stability, low temperature property and rate property of the battery. Summary of the Invention [Problem to be solved by the invention]

[0008] In order to solve the above technical problems, the present invention proposes a silane-based additive and a silane-based additive composition, which are stable compounds and suppress gas generation in a cell while improving high-temperature storage characteristics and high-temperature cycle characteristics of a battery. [Means for solving the problem]

[0009] The object of the present invention is achieved by the following technical solutions: In one aspect, the present invention proposes the use of a silane-based additive containing a carbon-carbon triple bond in an electrolyte to suppress cell gassing and having the structure shown in formula (I):

[0010] [ka] (Note that R1, R2, R3, and R4 are independently any one selected from an alkyl group, an alkynyl group, a fluoroalkyl group, and a fluoroalkynyl group, and at least one of R1, R2, R3, and R4 contains a carbon-carbon triple bond.)

[0011] In order to avoid problems such as low film formation efficiency at the interface between the material and the electrolyte and high internal resistance due to steric effects caused by too long alkyl or alkynyl group chains, preferably, R1, R2, R3, and R4 are independently one selected from C1-C6 alkyl groups, C2-C6 alkynyl groups, fluoro C1-C6 alkyl groups, and fluoro C2-C6 alkynyl groups. More preferably, R1, R2, R3, and R4 are independently one selected from methyl groups, ethyl groups, trifluoromethyl groups, trifluoroethyl groups, ethynyl groups, or propynyl groups. Most preferably, the silane-based additive is at least one selected from the following structures:

[0012] [ka]

[0013] The silane additive accounts for 0.1% to 5.0% of the total mass of the electrolyte, and at this concentration, the silane additive can play a role in suppressing gas generation in the cell. Preferably, the silane additive accounts for 0.2% to 3.0% of the total mass of the electrolyte.

[0014] In the silane-based additive of the present invention, oxidation polymerization or reduction polymerization occurs at the positive and negative electrodes during formation in the electrolyte, forming a dense surface film, which has a certain degree of ion permeability and can isolate the electrolyte from the highly oxidizing positive electrode (or the highly reducing negative electrode), thereby reducing the side reaction that occurs between the solvent in the electrolyte and the electrode sheet at high temperatures. For example, the decomposition reaction or oxidation reaction of the carbonate ester-based solvent generates carbon dioxide, carbon monoxide, alkanes, and olefin-based gases, causing the cell to generate gas during storage or standing. If the side reaction between the solvent and the electrode sheet can be suppressed, the generation of gas during high-temperature storage of the battery can be suppressed.

[0015] Although the silane compound of the present invention exerts the effect of suppressing gas generation in the cell during high-temperature storage, its high-temperature cycle characteristics are still not ideal, which may be due to the high impedance during unsaturated silane film formation, and the interface impedance inside the battery being a little too high.The inventors have found through research that adding other film-forming additives to the electrolyte can form a new surface film on the negative or positive electrode, affecting the structure of the surface film, thereby effectively reducing the electrode sheet impedance, and also improving the high-temperature storage characteristics and high-temperature cycle characteristics.

[0016] Therefore, the present invention also provides a composite additive of a silane-based additive and a film-forming additive in the electrolyte solution according to any one of the above, the film-forming additive having a film-forming potential of 1.5 V (vs. Li + / Li), occupying 0.1% to 8.0% of the total mass of the electrolyte, and the silane-based additive occupying 0.1% to 5.0% of the total mass of the electrolyte. Preferably, the film-forming additive occupies 0.2 to 3.0% of the total mass of the electrolyte, and the silane-based additive occupies 0.2 to 3.0% of the total mass of the electrolyte. More preferably, the film-forming additive occupies 0.2 to 2.0% of the total mass of the electrolyte, and the silane-based additive occupies 0.2 to 2.0% of the total mass of the electrolyte.

[0017] According to the use of the composite additive of the silane-based additive and the film-forming additive in the electrolytic solution, the film-forming additive is preferably at least one selected from an acid anhydride-based compound, a sulfonate-based compound, a sulfate-based compound, a trimethylsilyl ester-based compound, an unsaturated cyclic carbonate-based compound, and a fluorocyclic carbonate-based compound.

[0018] The acid anhydride compound is at least one selected from succinic anhydride, maleic anhydride, and citraconic anhydride, the sulfonate ester compound is at least one selected from 1,3-propane sultone, 1,4-butane sultone, methylenemethane disulfonate, and 1-propene 1,3-sultone, the sulfate ester compound is at least one selected from ethylene sulfate, cyclic trimethylene sulfate, cyclic 1,2-propylene sulfate, and 4,4'-biethylene sulfate, and the trimethylsilyl ester compound is at least one selected from ethylene sulfate, cyclic trimethylene sulfate, cyclic 1,2-propylene sulfate, and 4,4'-biethylene sulfate. The compound is at least one selected from tris(trimethylsilyl)borate, tris(trimethylsilyl)phosphate, tris(trimethylsilyl)phosphite, and tris(trimethylsilyl)trifluoromethanesulfonate, the unsaturated cyclic carbonate compound is selected from vinylene carbonate and / or vinylethylene carbonate, and the fluorocyclic carbonate compound is at least one selected from fluoroethylene carbonate, difluoroethylene carbonate, or trifluoromethylethylene carbonate. More preferably, the film-forming additive is at least one selected from vinylene carbonate, 1,3-propane sultone, tris(trimethylsilyl)phosphate, and ethylene sulfate.

[0019] The present invention also provides a lithium ion battery electrolyte solution comprising a lithium salt, an organic solvent, and the silane-based additive or a composite additive of a silane-based additive and a film-forming additive described in any one of the above.

[0020] The lithium salt may be any lithium salt commonly used in electrolyte solutions. Preferably, the lithium salt is at least one selected from lithium hexafluorophosphate, lithium tetrafluoroborate, lithium bis(oxalato)borate, lithium difluoro(oxalato)borate, lithium bis(fluorosulfonyl)imide, and lithium bis(trifluoromethanesulfonyl)imide, and the concentration of the lithium salt in the electrolyte solution is 0.3 M to 3 M. More preferably, the lithium salt includes lithium hexafluorophosphate, and the concentration in the electrolyte solution is 0.3 to 2 M.

[0021] The organic solvent may be a solvent that is often used in electrolytic solutions. Preferably, the organic solvent is at least one selected from C3-C6 carbonate compounds, C3-C8 carboxylate compounds, sulfone compounds, and ether compounds. More preferably, the C3-C6 carbonate compounds are at least one selected from ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, dipropyl carbonate, methyl propyl carbonate, and ethyl propyl carbonate, the C3-C8 carboxylate compounds are at least one selected from γ-butyrolactone, methyl acetate, methyl propionate, methyl butanoate, ethyl acetate, ethyl propionate, ethyl butanoate, propyl acetate, and propyl propionate, the sulfone compounds are selected from sulfolane, and the ether compounds are at least one selected from triethylene glycol dimethyl ether and tetraethylene glycol dimethyl ether.

[0022] The present invention also provides a lithium ion battery comprising a positive electrode, a negative electrode, a separator, and the electrolyte solution according to any one of the above claims.

[0023] The positive electrode may be a positive electrode commonly used in the field of lithium batteries. Preferably, the positive electrode active material is LiNi 1-x-y-z Cox Mn y Al z One selected from O2, lithium nickel manganese oxide, lithium cobalt oxide, lithium-rich manganese solid solution, lithium manganese oxide, or lithium iron phosphate, where 0≦x≦1, 0≦y≦1, 0≦z≦1, and 0≦x+y+z≦1.

[0024] The negative electrode may be a negative electrode commonly used in the field of lithium batteries. Preferably, the negative electrode active material is one selected from artificial graphite, coated natural graphite, silicon-carbon negative electrode, silicon negative electrode, and lithium titanate.

[0025] The voltage of the lithium ion battery may be in a general battery voltage range of 2.5 to 4.2 V or in a high voltage test range of 4.2 V or more.

[0026] The present invention also provides a method for simultaneously improving the high-temperature storage characteristics and high-temperature cycle characteristics of a battery, the method comprising adding to an electrolyte a composite additive of a silane-based additive having a structure of formula (I) described in any one of the above, which accounts for 0.1% to 5.0% of the total mass of the electrolyte, and another film-forming additive, which accounts for 0.1% to 8.0% of the total mass of the electrolyte.

[0027] In another aspect, the present invention also provides a method for producing a method for treating a pulmonary arthritis, comprising: The composition comprises: A silane-based additive that suppresses gas generation in a cell, accounts for 0.01% to 10.0% of the total mass of the electrolyte, and has a structure represented by the following formula (I): The present invention provides use of a silane-based additive composition in an electrolyte, the composition comprising: a fluorine-containing lithium salt-based additive that improves the initial impedance of a cell and suppresses a sustained increase in the impedance of the cell during cycling, the fluorine-containing lithium salt-based additive accounting for 0.1% to 10.0% of the total mass of the electrolyte.

[0028] [ka] (Note that R1, R2, R3, and R4 are independently any one selected from an alkyl group, an alkynyl group, a fluoroalkyl group, and a fluoroalkynyl group, and at least one of R1, R2, R3, and R4 contains a carbon-carbon triple bond.)

[0029] More preferably, the silane-based additive accounts for 0.1% to 3.0% of the total mass of the electrolyte, and the fluorine-containing lithium salt-based additive accounts for 0.2% to 5.0% of the total mass of the electrolyte.

[0030] According to the use of the above silane-based additive composition in the electrolyte, preferably, R1, R2, R3, and R4 are independently selected from a C1-C6 alkyl group, a C2-C6 alkynyl group, a fluoro C1-C6 alkyl group, and a fluoro C2-C6 alkynyl group, and more preferably, the silane-based additive is at least one selected from the following structures:

[0031] [ka]

[0032] The silane additive is oxidized and decomposed at the positive electrode before the solvent, forms a stable protective film on the surface of the positive electrode, suppresses the parasitic reaction between the electrolyte and the positive electrode material, and prevents the elution of the positive electrode metal ions, thereby improving the high-temperature storage characteristics of the battery. In addition, the silane additive of the present invention has a lower initial impedance than conventional high-temperature additives, which is advantageous in improving the overall characteristics of the battery.

[0033] The fluorine-containing lithium salt additive is a fluorine-containing lithium salt compound with boron or phosphorus as the central ion, and preferably, the fluorine-containing lithium salt additive is at least one selected from lithium difluoro(oxalato)borate (abbreviation LiDFOB), lithium tetrafluoroborate (abbreviation LiBF4), lithium difluorobis(oxalato)phosphate (abbreviation LiDFOP), and lithium tetrafluoro(oxalato)phosphate (abbreviation LiTFOP). The fluorine-containing lithium salt additive can form an interface film with higher ionic conductivity and favorable charge transfer, and the interface film continuously modifies the interface film of the positive and negative electrodes, suppresses a sustained increase in the impedance of the cell during the cycle of the battery, and improves the long-term high-temperature cycle stability of the battery.

[0034] By using a silane-based additive and a fluorine-containing salt-based additive in combination in the electrolyte, gas generation during high-temperature storage of the battery can be further suppressed, the initial impedance and the increase in impedance during battery cycling can be suppressed, the capacity recovery characteristics and capacity retention characteristics of the battery can be improved, and the rate characteristics and low-temperature discharge characteristics of the battery can be improved.

[0035] The present invention also provides a lithium ion battery electrolyte comprising a lithium salt, an organic solvent, and a composition of the silane-based additive and the fluorine-containing lithium salt-based additive described in any one of the above.

[0036] The lithium salt may be any lithium salt commonly used in electrolyte solutions. Preferably, the lithium salt is at least one selected from lithium hexafluorophosphate, lithium bis(fluorosulfonyl)imide, and lithium bis(trifluoromethanesulfonyl)imide, and the molar concentration of the lithium salt in the electrolyte solution is 0.4 to 1.6 mol / L. More preferably, the lithium salt includes lithium hexafluorophosphate, and the molar concentration of the lithium hexafluorophosphate in the electrolyte solution is 0.6 to 1.2 mol / L.

[0037] The organic solvent may be a solvent that is often used in electrolytic solutions. Preferably, the organic solvent is at least one selected from C3-C6 carbonate compounds, C3-C8 carboxylate compounds, sulfone compounds, and ether compounds. More preferably, the C3-C6 carbonate compounds are at least one selected from ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, dipropyl carbonate, methyl propyl carbonate, and ethyl propyl carbonate, the C3-C8 carboxylate compounds are at least one selected from γ-butyrolactone, methyl acetate, methyl propionate, methyl butanoate, ethyl acetate, ethyl propionate, ethyl butanoate, propyl acetate, and propyl propionate, the sulfone compounds are selected from sulfolane, and the ether compounds are at least one selected from triethylene glycol dimethyl ether and tetraethylene glycol dimethyl ether. Most preferably, the C3 to C6 carbonate ester compound is at least one selected from ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, dipropyl carbonate, methyl propyl carbonate, and ethyl propyl carbonate, the C3 to C8 carboxylate ester compound is at least one selected from γ-butyrolactone, methyl acetate, methyl propionate, methyl butanoate, ethyl acetate, ethyl propionate, ethyl butanoate, propyl acetate, and propyl propionate, the sulfone compound is selected from sulfolane, and the ether compound is at least one selected from triethylene glycol dimethyl ether and tetraethylene glycol dimethyl ether.

[0038] The present invention also provides a lithium ion battery comprising a positive electrode, a negative electrode, a separator, and the electrolyte solution according to any one of the above claims.

[0039] The positive electrode may be a positive electrode commonly used in the field of lithium batteries. Preferably, the positive electrode active material is a nickel-cobalt-manganese ternary material LiNi 1-x-y-z Co x Mn y Al z O 2、 One selected from lithium nickel manganese oxide, lithium cobalt oxide, lithium-rich manganese solid solution, lithium manganese oxide, or lithium iron phosphate, where 0≦x≦1, 0≦y≦1, 0≦z≦1, and 0≦x+y+z≦1.

[0040] The negative electrode may be a negative electrode commonly used in the field of lithium batteries. Preferably, the negative electrode active material is one selected from artificial graphite, coated natural graphite, silicon-carbon negative electrode, silicon negative electrode, and lithium titanate.

[0041] The voltage of the lithium ion battery may be in a general battery voltage range of 2.0 to 4.2 V, or in a high voltage test range of 4.2 V or more.

[0042] The present invention also provides a method for simultaneously improving the high-temperature storage characteristics and high-temperature cycle characteristics of a battery, comprising adding a composition of the silane-based additive and the fluorine-containing lithium salt-based additive described in any one of the above to an electrolyte solution. Effect of the Invention

[0043] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The silane-based additive containing a carbon-carbon triple bond of the present invention is more stable at high temperatures when applied to an electrolyte, and the CEI film formed on the surface of the positive or negative electrode is less likely to be destroyed, reducing gas generation, inhibiting gas generation in the cell, and improving the high-temperature storage characteristics of the battery. 2. The present invention uses a silane-based additive in combination with other film-forming additives to form a new surface film on the negative or positive electrode, effectively reducing the impedance of the electrode sheet and simultaneously improving the high-temperature storage characteristics and high-temperature cycle stability of the battery. 3. The silane-based additive containing a carbon-carbon triple bond of the present invention can form a protective layer on the surface of the positive electrode, thereby suppressing the parasitic reaction between the electrolyte and the positive electrode material during high-temperature storage, suppressing the catalytic decomposition of the electrolyte by the positive electrode material, and effectively improving the volume expansion during high-temperature storage and high-temperature cycles, and has a lower initial impedance and impedance increase rate than the high-temperature additives of the prior art. In addition, the fluorine-containing lithium salt-based additive of the present invention simultaneously and continuously causes a film-forming reaction on the positive and negative electrodes, adjusts the structure and components of the interface film of the positive and negative electrodes, promotes the formation of an interface film with low impedance and high stability on the positive and negative electrodes, suppresses the sustained increase in impedance during cycles, and improves the rate characteristics, low-temperature discharge characteristics, and long-term high-temperature cycle stability of the battery. When applied to a ternary lithium-ion battery or other high-voltage battery system, the present invention can simultaneously improve the high-temperature storage characteristics and high-temperature cycle stability of the battery by using a silane-based additive containing a carbon-carbon triple bond in combination with a fluorine-containing lithium salt-based additive, and can also achieve both low-temperature discharge characteristics and rate characteristics of the battery. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0044] The present invention will be further described below with reference to specific examples, but the present invention is not limited to these specific embodiments. As will be apparent to those skilled in the art, the present invention includes all possible alternatives, modifications and equivalents that may be included within the scope of the claims. EXAMPLES

[0045] In one aspect, preparations and examples of embodiments of the present invention are as follows.

[0046] Preparation Example 1 Preparation of base electrolyte: In a high-purity argon glove box with oxygen and water contents of 0.1 ppm or less, ethylene carbonate (EC), diethyl carbonate (DEC), and methyl ethyl carbonate (EMC) were mixed in a mass ratio of EC:DEC:EMC = 3:2:5, and then lithium hexafluorophosphate (LiPF6) with a mass percentage of 12.5 wt% was slowly added to the mixture. Preparation of lithium-ion battery: 4.3V LiNi after thoroughly drying the electrolyte of the lithium-ion battery prepared above. 0.83 Co 0.07 Mn 0.2 The mixture was injected into an O2 / graphite polymer battery, which was then left at 45°C for formation and secondary sealing, after which capacity grading and testing were performed.

[0047] Example 1.1 The procedure of this example was the same as that of Preparation Example 1, except that Compound 1 was added to the electrolyte in an amount of 0.5 wt % of the total weight of the electrolyte.

[0048] Example 1.2 The procedure of this example was the same as that of Preparation Example 1, except that Compound 3 was added to the electrolyte in an amount of 0.5 wt % of the total weight of the electrolyte.

[0049] Example 1.3 The procedure of this example was the same as that of Preparation Example 1, except that Compound 5 was added to the electrolyte in an amount of 0.5 wt % of the total weight of the electrolyte.

[0050] Example 1.4 The procedure of this example was the same as that of Preparation Example 1, except that Compound 10 was added to the electrolyte in an amount of 0.5 wt % of the total weight of the electrolyte.

[0051] Example 1.5 The procedure of this example was the same as that of Preparation Example 1, except that Compound 1 was added to the electrolyte in an amount of 1.5 wt % of the total weight of the electrolyte.

[0052] Example 1.6 The procedure of this example was the same as that of Preparation Example 1, except that Compound 1 was added to the electrolyte in an amount of 0.5 wt % of the total electrolyte mass, and vinylene carbonate (VC) was added in an amount of 1.0 wt % of the total electrolyte mass.

[0053] Example 1.7 The procedure of this example was the same as that of Preparation Example 1, except that the electrolyte contained Compound 3, which accounted for 0.5 wt % of the total electrolyte mass, and 1,3-propane sultone (PS), which accounted for 1.0 wt % of the total electrolyte mass.

[0054] Example 1.8 The procedure of this example was the same as that of Preparation Example 1, except that the electrolyte contained Compound 5, which accounted for 0.5 wt % of the total electrolyte mass, and Tris(trimethylsilyl)phosphate (TMSP), which accounted for 1.0 wt % of the total electrolyte mass.

[0055] Example 1.9 The procedure of this example was the same as that of Preparation Example 1, except that the electrolyte contained Compound 7, which accounted for 0.5 wt % of the total electrolyte mass, and ethylene sulfate (DTD), which accounted for 1.0 wt % of the total electrolyte mass.

[0056] Example 1.10 The procedure of this example was the same as that of Preparation Example 1, except that the electrolyte contained Compound 10, which accounted for 0.5 wt % of the total electrolyte mass, and 1-propene-1,3-sultone (PES), which accounted for 1.0 wt % of the total electrolyte mass.

[0057] Example 1.11 The procedure of this example was the same as that of Preparation Example 1, except that Compound 1 was added to the electrolyte in an amount of 0.2 wt % of the total electrolyte mass, and vinylene carbonate (VC) was added in an amount of 1.0 wt % of the total electrolyte mass.

[0058] Example 1.12 The procedure of this example was the same as that of Preparation Example 1, except that the electrolyte contained Compound 3, which accounted for 1.0 wt % of the total electrolyte mass, and vinylene carbonate (VC), which accounted for 1.0 wt % of the total electrolyte mass.

[0059] Example 1.13 The procedure of this example was the same as that of Preparation Example 1, except that the electrolyte contained Compound 5, which accounted for 2.0 wt % of the total electrolyte mass, and vinylene carbonate (VC), which accounted for 1.0 wt % of the total electrolyte mass.

[0060] Example 1.14 The procedure of this example was the same as that of Preparation Example 1, except that the electrolyte contained Compound 10, which accounted for 3.0 wt % of the total electrolyte mass, and vinylene carbonate (VC), which accounted for 1.0 wt % of the total electrolyte mass.

[0061] Example 1.15 The procedure of this example was the same as that of Preparation Example 1, except that Compound 1 was added to the electrolyte in an amount of 0.5 wt % of the total electrolyte mass, and vinylene carbonate (VC) was added in an amount of 0.2 wt % of the total electrolyte mass.

[0062] Example 1.16 The procedure of this example was the same as that of Preparation Example 1, except that the electrolyte contained Compound 5, which accounted for 0.5 wt % of the total electrolyte mass, and vinylene carbonate (VC), which accounted for 2.0 wt % of the total electrolyte mass.

[0063] Example 1.17 The procedure of this example was the same as that of Preparation Example 1, except that the electrolyte contained Compound 9, which accounted for 0.5 wt % of the total electrolyte mass, and vinylene carbonate (VC), which accounted for 3.0 wt % of the total electrolyte mass.

[0064] Example 1.18 The procedure of this example was the same as that of Preparation Example 1, except that the electrolyte contained Compound 3, which accounted for 0.5 wt % of the total electrolyte mass, and vinylene carbonate (VC), which accounted for 8.0 wt % of the total electrolyte mass.

[0065] Comparative Example 1.1 The procedure of this comparative example was the same as that of Preparation Example 1, except that the compound 1,3-propane sultone (PS) was added to the electrolyte, accounting for 0.5 wt % of the total electrolyte mass.

[0066] Comparative Example 1.2 The procedure for this comparative example was the same as that of Preparation Example 1, except that the electrolyte contained the compound adiponitrile (ADN), which accounted for 0.5 wt % of the total electrolyte mass.

[0067] Comparative Example 1.3 The procedure for this comparative example was the same as that of Preparation Example 1, except that the electrolyte contained the compound diphenyldimethoxysilane (DPDMS), which accounted for 0.5 wt % of the total electrolyte mass.

[0068] Comparative Example 1.4 The procedure for this comparative example was the same as that of Preparation Example 1, except that the electrolyte contained the compound vinylene carbonate (VC), which accounted for 1.5 wt % of the total electrolyte mass.

[0069] Comparative Example 1.5 The procedure of this comparative example was the same as that of Preparation Example 1, except that vinylene carbonate (VC) was added to the electrolyte in an amount of 1.0 wt % of the total electrolyte mass.

[0070] Comparative Example 1.6 The procedure of this comparative example was the same as that of Preparation Example 1, except that 1,3-propane sultone (PS) was added to the electrolyte in an amount of 1.0 wt % of the total electrolyte mass.

[0071] Comparative Example 1.7 The procedure of this comparative example was the same as that of Preparation Example 1, except that 1-propene-1,3-sultone (PES) was added to the electrolyte, accounting for 1.0 wt % of the total electrolyte mass.

[0072] Comparative Example 1.8 The procedure of this comparative example was the same as that of Preparation Example 1, except that tris(trimethylsilyl)phosphate (TMSP) was added to the electrolyte in an amount of 1.0 wt % of the total electrolyte mass.

[0073] Comparative Example 1.9 The procedure of this comparative example was the same as that of Preparation Example 1, except that ethylene sulfate (DTD) was added to the electrolyte in an amount of 1.0 wt % of the total mass of the electrolyte.

[0074] Comparative Example 1.10 The procedure of this comparative example was the same as that of Preparation Example 1, except that vinylene carbonate (VC) was added to the electrolyte in an amount of 2.0 wt % of the total electrolyte mass.

[0075] Comparative Example 1.11 The procedure of this comparative example was the same as that of Preparation Example 1, except that vinylene carbonate (VC) was added to the electrolyte in an amount of 8.0 wt % of the total electrolyte mass.

[0076] Comparative Example 1.12 The procedure of this comparative example was the same as that of Preparation Example 1, except that the electrolyte contained Compound 5, which accounted for 0.5 wt % of the total electrolyte mass, and adiponitrile (ADN), which accounted for 1.0 wt % of the total electrolyte mass.

[0077] Comparative Example 1.13 The procedure of this comparative example was the same as that of Preparation Example 1, except that the electrolyte contained Compound 7, which accounted for 0.5 wt % of the total electrolyte mass, and trimethylsilylmethylisocyanate (TMSNCS), which accounted for 1.0 wt % of the total electrolyte mass. For Examples 1.1 to 1.18 and Comparative Examples 1.1 to 1.13, the room temperature cycle characteristics, high temperature cycle characteristics, and high temperature storage characteristics of the batteries were tested. The test results are shown in Table 1.

[0078] [Table 1]

[0079] Comparing the test results of Examples 1.1 to 1.4 and Comparative Examples 1.1 to 1.3, it was found that the addition of the silane-based additive containing the carbon-carbon triple bond of the present invention to the electrolyte solution reduced gas generation in the cell. Comparing the test results of Examples 1.5 to 1.18 and Comparative Examples 1.4 to 1.11, it was found that the use of a silane-based additive containing a carbon-carbon triple bond in combination with a film-forming additive improved the high-temperature cycle characteristics of the cell and also improved the high-temperature storage characteristics. Among them, vinylene carbonate, 1,3-propane sultone, tris(trimethylsilyl)phosphate, and ethylene sulfate were highly effective. As a result of comparing the test results of Examples 1.5 to 1.10 and Comparative Examples 1.12 to 1.13, the high-temperature cycle characteristics and high-temperature storage characteristics were more significantly improved when the silane-based additive of the present invention was used in combination with the film-forming additive, compared with the case where the additive was used in combination with other general additives having excellent high-temperature cycle characteristics.

[0080] In another aspect, preparations and examples of embodiments of the present invention are as follows.

[0081] Preparation Example 2: Preparation of base electrolyte: In a high-purity argon glove box with oxygen and water contents of 0.1 ppm or less, ethylene carbonate (EC), diethyl carbonate (DEC), and methyl ethyl carbonate (EMC) were mixed in a mass ratio of EC:DEC:EMC = 3:2:5, and lithium hexafluorophosphate (LiPF6) was added to the mixture until the molar concentration reached 1 mol / L. Preparation of lithium-ion battery: 4.3V LiNi after thoroughly drying the electrolyte of the lithium-ion battery prepared above. 0.83 Co 0.07 Mn 0.2 The mixture was poured into an O2 / graphite battery, the battery was left at 45°C, and after formation and secondary sealing, the battery was subjected to capacity grading and testing.

[0082] Example 2.1 The operation of this example was the same as that of Preparation Example 2, except that 0.5% of Compound 1 based on the total mass of the electrolyte and 0.5% of lithium difluoro(oxalato)borate (LiDFOB) based on the total mass of the electrolyte were added to the electrolyte.

[0083] Example 2.2 The operation of this example was the same as that of Preparation Example 2, except that 0.5% of Compound 1 based on the total mass of the electrolyte and 1.0% of lithium difluoro(oxalato)borate (LiDFOB) based on the total mass of the electrolyte were added to the electrolyte.

[0084] Example 2.3 The operation of this example was the same as that of Preparation Example 2, except that 0.5% of Compound 1 based on the total mass of the electrolyte and 2.0% of lithium difluoro(oxalato)borate (LiDFOB) based on the total mass of the electrolyte were added to the electrolyte.

[0085] Example 2.4 The operation of this example was the same as that of Preparation Example 2, except that 0.5% of Compound 1 based on the total mass of the electrolyte and 3.0% of lithium difluoro(oxalato)borate (LiDFOB) based on the total mass of the electrolyte were added to the electrolyte.

[0086] Example 2.5 The operation of this example was the same as that of Preparation Example 2, except that 0.5% of Compound 1 based on the total mass of the electrolyte and 5.0% of lithium difluoro(oxalato)borate (LiDFOB) based on the total mass of the electrolyte were added to the electrolyte.

[0087] Example 2.6 The operation of this example was the same as that of Preparation Example 2, except that 1.0% of Compound 1 and 1.0% of lithium difluoro(oxalato)borate (LiDFOB) were added to the electrolyte solution based on the total weight of the electrolyte solution.

[0088] Example 2.7 The operation of this example was the same as that of Preparation Example 2, except that 2.0% of Compound 1 based on the total mass of the electrolyte and 1.0% of lithium difluoro(oxalato)borate (LiDFOB) based on the total mass of the electrolyte were added to the electrolyte.

[0089] Example 2.8 The operation of this example was the same as that of Preparation Example 2, except that 3.0% of Compound 1 based on the total mass of the electrolyte and 1.0% of lithium difluoro(oxalato)borate (LiDFOB) based on the total mass of the electrolyte were added to the electrolyte.

[0090] Example 2.9 The operation of this example was the same as that of Preparation Example 2, except that 0.5% of compound 3 based on the total mass of the electrolyte and 1.0% of lithium difluoro(oxalato)borate (LiDFOB) based on the total mass of the electrolyte were added to the electrolyte.

[0091] Example 2.10 The operation of this example was the same as that of Preparation Example 2, except that 0.5% of compound 3 based on the total mass of the electrolyte and 1.0% of lithium difluorobis(oxalato)phosphate (LiDFOP) based on the total mass of the electrolyte were added to the electrolyte.

[0092] Example 2.11 The operation of this example was the same as that of Preparation Example 2, except that 0.5% of Compound 3 based on the total mass of the electrolyte and 1.0% of lithium tetrafluoro(oxalato)phosphate (LiTFOP) based on the total mass of the electrolyte were added to the electrolyte.

[0093] Example 2.12 The operation of this example was the same as that of Preparation Example 2, except that 0.5% of Compound 3 based on the total mass of the electrolyte and 1.0% of lithium tetrafluoroborate (LiBF4) based on the total mass of the electrolyte were added to the electrolyte.

[0094] Example 2.13 The operation of this example was the same as that of Preparation Example 2, except that 0.5% of compound 5 based on the total mass of the electrolyte and 1.0% of lithium difluoro(oxalato)borate (LiDFOB) based on the total mass of the electrolyte were added to the electrolyte.

[0095] Example 2.14 The operation of this example was the same as that of Preparation Example 2, except that 0.5% of compound 7 based on the total mass of the electrolyte and 1.0% of lithium difluoro(oxalato)borate (LiDFOB) based on the total mass of the electrolyte were added to the electrolyte.

[0096] Example 2.15 The operation of this example was the same as that of Preparation Example 2, except that 0.5% of compound 10 based on the total mass of the electrolyte and 1.0% of lithium difluoro(oxalato)borate (LiDFOB) based on the total mass of the electrolyte were added to the electrolyte.

[0097] Comparative Example 2.1 The procedure for this comparative example was the same as in Preparation Example 2, ie, using the base electrolyte and no additives.

[0098] Comparative Example 2.2 The procedure of this comparative example was the same as that of Preparation Example 2, except that 0.5% of Compound 1 based on the total mass of the electrolyte was added to the electrolyte.

[0099] Comparative Example 2.3 The procedure of this comparative example was the same as that of Preparation Example 2, except that 1.0% of Compound 1 was added to the electrolyte solution based on the total mass of the electrolyte solution.

[0100] Comparative Example 2.4 The procedure of this comparative example was the same as that of Preparation Example 2, except that lithium difluoro(oxalato)borate (LiDFOB) was added to the electrolyte in an amount of 1.0% based on the total mass of the electrolyte.

[0101] Comparative Example 2.5 The procedure of this comparative example was the same as that of Preparation Example 2, except that 1.0% of 1,3-propane sultone (PS) was added to the electrolyte solution based on the total electrolyte solution mass.

[0102] Comparative Example 2.6 The procedure of this comparative example was the same as that of Preparation Example 2, except that 1.0% of 1,3-propane sultone (PS) and 1.0% of lithium difluoro(oxalato)borate (LiDFOB) were added to the electrolyte solution based on the total weight of the electrolyte solution.

[0103] Comparative Example 2.7 The procedure of this comparative example was the same as that of Preparation Example 2, except that 1.0% of Compound 3 was added to the electrolyte solution based on the total weight of the electrolyte solution.

[0104] Comparative Example 2.8 The procedure of this comparative example was the same as that of Preparation Example 2, except that lithium difluorobis(oxalato)phosphate (LiDFOP) was added to the electrolyte in an amount of 1.0% based on the total mass of the electrolyte.

[0105] Comparative Example 2.9 The procedure of this comparative example was the same as that of Preparation Example 2, except that 0.5% of 1-propene-1,3-sultone (PST) based on the total mass of the electrolyte was added to the electrolyte.

[0106] Comparative Example 2.10 The procedure of this comparative example was the same as that of Preparation Example 2, except that 0.5% PST and 1.0% lithium difluorobis(oxalato)phosphate (LiDFOP) were added to the electrolyte solution based on the total weight of the electrolyte solution.

[0107] Comparative Example 2.11 The procedure of this comparative example was the same as that of Preparation Example 2, except that 0.5% PST and 1.0% lithium difluoro(oxalato)borate (LiDFOB) were added to the electrolyte solution based on the total weight of the electrolyte solution.

[0108] Comparative Example 2.12 The procedure of this comparative example was the same as that of Preparation Example 2, except that 1.0% of tris(trimethylsilyl)borate (TMSB) was added to the electrolyte solution based on the total weight of the electrolyte solution.

[0109] Comparative Example 2.13 The procedure of this comparative example was the same as that of Preparation Example 2, except that 1.0% tris(trimethylsilyl)borate (TMSB) and 0.5% lithium difluoro(oxalato)borate (LiDFOB) were added to the electrolyte solution based on the total weight of the electrolyte solution.

[0110] For Examples 2.1 to 2.15 and Comparative Examples 2.1 to 2.13, the initial DCR, low-temperature discharge at -20°C, battery 3C rate discharge, high-temperature cycle characteristics, and high-temperature storage characteristics of the nickel-cobalt-manganese ternary batteries were tested. The test results are shown in Table 2.

[0111] [Table 2]

[0112] As can be seen from the above results, both the silane additive and the fluorine-containing lithium salt additive have a synergistic effect, and both are indispensable, ensuring high-temperature storage characteristics and high-temperature cycle stability while achieving low-temperature characteristics and rate characteristics of the battery. When the silane additive and the fluorine-containing lithium salt additive are used in combination, the overall characteristics are superior to those of the comparative example that uses no additive, a single silane additive or a single fluorine-containing lithium salt additive, and a combination of a general high-temperature additive (such as PS, PST, TMSB, etc.) and a fluorine-containing lithium salt additive.

Claims

1. a silane-based additive composition comprising: a silane-based additive which is at least one selected from the following structures, accounts for 0.1% to 3.0% of the total mass of the lithium-ion battery electrolyte and suppresses gas generation from the electrolyte in a cell; and a fluorine-containing lithium salt-based additive which accounts for 0.2% to 3.0% of the total mass of the lithium-ion battery electrolyte and improves the initial impedance of the cell and suppresses an increase in the impedance of the cell during cycles; A lithium salt; An organic solvent; Including, 【Chemistry 1】 the fluorine-containing lithium salt additive is at least one selected from the group consisting of lithium difluoro(oxalato)borate, lithium tetrafluoroborate, lithium difluorobis(oxalato)phosphate, and lithium tetrafluoro(oxalato)phosphate; the lithium salt is at least one selected from the group consisting of lithium hexafluorophosphate, lithium bis(fluorosulfonyl)imide, and lithium bis(trifluoromethanesulfonyl)imide; The lithium ion battery electrolyte has a molar concentration of the lithium salt in the lithium ion battery electrolyte of 0.4 mol / L to 1.6 mol / L.

2. The lithium ion battery electrolyte according to claim 1, wherein the organic solvent is at least one selected from the group consisting of C3 to C6 carbonate ester compounds, C3 to C8 carboxylate ester compounds, sulfone compounds, and ether compounds.

3. A positive electrode sheet containing a positive electrode active material; a negative electrode sheet containing a negative electrode active material; A separator; A lithium ion battery comprising the lithium ion battery electrolyte according to claim 1 or 2.

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