KR20160055083A - Electrolyte formulation for reduced gassing wide temperature range cycling - Google Patents

Abstract

Provided is a secondary battery having a specific combination of an anode, a cathode, and electrolyte formulation. The electrolyte formulation comprises an additive system and a salt system. The additive system includes a sulfonyl group-containing first additive, a gas generation inhibitor, and a second additive. The salt system includes lithium salt and air salt. The disclosed electrolyte formulation has reduced gas generation in the wide range of temperature and improved capacity.

Description

ELECTROLYTE FORMULATION FOR REDUCED GASSING WIDE TEMPERATURE RANGE CYCLING [0002]

This application is a continuation-in-part of International Application No. PCT / US2013 / 045513 entitled " Non-Aqueous Electrolytic Rechargeable Batteries for Extended Temperature Range Operation ", filed June 12, 2013, U.S. Provisional Application No. 61 / 658,712 entitled " Microhybrid Battery " and filed on June 12, 2012, entitled " Lithium Ion Cell with Non-Aqueous Electrolyte with a Solvent Including an SO Bond " 61 / 658,704, the entire contents of which are incorporated herein by reference.

This disclosure relates to an electrolyte formulation for use in a secondary cell, the electrolyte formulation containing at least one sulfonyl-containing first additive, a specific salt system and a gas inhibitor additive in a certain ratio.

The secondary cell generates energy by an electrochemical reaction. In a typical secondary cell, the cell is designed to provide optimal performance at or near room temperature. Very high or very low temperatures impair the performance and / or lifetime of the cell. In order to solve performance problems at extreme temperatures, volume, weight, complexity and cost are increased because the battery incorporates a heating system and / or a cooling system. In many cases, this may limit the use of the battery for application in extreme temperature environments.

Recently, secondary batteries have been designed to have cells with a specific combination of anode, cathode, and electrolyte composition to maintain long cycle life at high temperatures and to provide power at low temperatures. For example, inventor Cho of International Laid-Open Publication No. 2013/188594 (incorporated herein by reference) discloses an electrolyte formulation comprising a sulfonyl group-containing first additive for use in a secondary cell. The use of a sulfonyl group-containing additive in an electrolyte as disclosed by Cho can significantly reduce the need for a thermal management system because it can provide a battery that maintains its cycle life at high temperatures and provides power at low temperatures.

Cho discloses a secondary battery comprising a nonaqueous electrolyte solution and an organic solvent mixture comprising LiPF ₆ , specifically a lithium salt of 0.6 to 2 M, and the organic solvent mixture comprises 35 vol% ethylenecarbonate, 5 vol 0.1 to 5% by weight of ethylene sulfite, which is at least one sulfonyl group-containing additive, and 0.2 to 8% by volume of ethylene carbonate, 50% by volume of propylene carbonate, 50% by volume of ethylmethyl carbonate and 10% by volume of diethyl carbonate, Vinylene carbonate. The electrolyte formulation provided by Cho increases the power for cold cranking engine of the engine and maintains its long life at high temperature compared to the lead acid battery.

The use of a sulfonyl group-containing additive together with vinylene carbonate in the organic electrolyte provides a stable, low-impedance secondary lithium ion cell. The sulfonyl group-containing additive is capable of lowering the impedance by forming a stable solid electrolyte interface (SEI) by reacting with the anode. In the SEI interface, the ionic conductivity is higher than the ion conductivity with the electrolyte even without using an additive. Vinylene carbonate may also be effective in reducing decomposition of the sulfonyl additive by anchoring the carbon-based anode during the initial charge so that the SEI is less soluble.

However, the inventors have recognized that improved electrolyte formulations based on electrolytes described herein by Cho can be provided to improve extreme temperature performance and reduce gas evolution. There is provided an electrolyte preparation comprising a sulfonyl group-containing first additive, a gas generation inhibitor, a second additive and a salt system. The electrolyte formulation also includes vinylene carbonate and a solvent system. Electrolyte formulations can be used in a variety of cell structures, but they are particularly advantageous because they can reduce gas generation.

The disclosed electrolyte formulations can reduce gas generation over a wide temperature range during the cycle. In addition, the ratio between the sulfonyl group additive and the vinylene carbonate can be adjusted to maintain an improved SEI layer for improved cell cycling efficiency. As provided herein, the optimal electrolyte formulation reduces / maintains impedance to provide improved power during cold start and reduces gas generation during hot cycling and / or storage.

As provided herein, the sulfonyl group-containing first additive may be from 0.1 to 5% by weight of the electrolyte formulation. The gas generation inhibitor may be 2% by weight or less of the electrolyte preparation, and the second additive may be 0.1 to 5% by weight of the electrolyte preparation. Additional additives may be selected to reduce the loading of vinylene carbonate while maintaining good SEI evolution. Salt systems can contain mixed lithium salts with co-salts, and the atmospheric salts are less prone to cause lysic acid degradation.

It is to be understood that the above summary is provided for the purpose of introducing the concepts described in the detailed description in a simplified form. This does not imply a representation of a core or essential feature of the claimed subject matter, and the claims are individually defined by the claims which follow the detailed description. Also, the claims are not limited to the practice of solving any of the disadvantages described above or any part of the disclosure.

Figure 1 shows the initial capacity loss of the electrolyte formulation in the LFP / graphite cell compared to the reference electrolyte.
Figure 2 shows the initial capacity loss of an electrolyte formulation in a cell comprising an NCM cathode and a graphite anode compared to a counter electrolyte.
Figure 3 shows the impedance of the electrolyte formulation in the LFP / graphite cell versus the reference electrolyte.
Figure 4 shows the impedance of the electrolyte formulation in the NCM / graphite cell versus the control electrolyte.
5A shows the hybrid pulse power capability (HPPC) at 23 DEG C of the electrolyte formulation in the LFP / graphite cell at 1 second pulse power versus the reference electrolyte.
Figure 5b shows the hybrid pulse power capability (HPPC) at 23 占 폚 of the electrolyte formulation in an LFP / graphite cell at 10 seconds pulse power versus the reference electrolyte.
6A shows the hybrid pulse power capability (HPPC) at -20 캜 of the electrolyte formulation in the LFP / graphite cell at 1 second pulse power versus the reference electrolyte.
Figure 6b shows the hybrid pulse power capability (HPPC) at -20 캜 of the electrolyte formulation in the LFP / graphite cell at a 10 second pulse power versus the counter electrolyte.
Figure 7 shows the power obtained from cold-start experiments at -30 [deg.] C using an electrolyte formulation in an LFP / graphite cell versus a counter electrolyte.
Figure 8 shows the power obtained from a cold start test at -30 캜 for an NCM / graphite cell containing an electrolyte formulation as compared to the control electrolyte.
Figure 9 shows the results of a high temperature cycle life test for an NCM / graphite cell comprising an electrolyte formulation as compared to a counter electrolyte.
Figure 10 shows the volume change during storage at 55 [deg.] C of the LFP / graphite cell containing the electrolyte formulation compared to the control electrolyte.
Figure 11 shows an exemplary pouch structure for use with an electrolyte formulation.

The forms of the present disclosure will be described with reference to the embodiments described above by way of example. The components, process steps, and other elements may be substantially identical in one or more embodiments, and are described cooperatively and at least by repeating. However, the cooperative elements may be somewhat different.

The present disclosure provides an optimal electrolyte formulation comprising a sulfonyl group-containing first additive, a gas generation inhibitor, a second additive for reducing impedance, and a salt system. This optimal electrolyte formulation improves unexpected initial capacity loss compared to the counter electrolyte formulation shown in Figures 1 and 2. In addition, the optimal electrolyte formulation provides a direct current and alternating current resistance (DCR, ACR) similar to and / or reduced to the counter electrolyte formulation shown in Figures 3,4, 5a, 5b, 6a and 6b. The optimal electrolyte formulation also exhibits an unexpected improvement in cycling over the extended low temperature starting power shown in Figures 7 and 8 and the broad temperature range shown in Figure 9. [ In addition, certain electrolyte preparations have unpredictable results in reducing impedance while simultaneously reducing gas generation, as shown in Fig. Since the gas production of the electrolyte preparation is small, the electrolyte preparation can be used in various cell structures, specifically, the pouch structure shown in Fig.

As described above, the electrolyte formulation provides low gas generation at high temperatures while providing low impedance at very low temperatures and provides excellent SEI deployment. Table 1 lists the ranges of additives and salt systems of the exemplary electrolyte formulation according to this disclosure.

As shown in Table 1 above, the electrolyte formulation can be considered to have an additive system and a salt system. Additive systems each contain less than 5% by weight components. The additive system described above comprises a sulfonyl group-containing first additive, vinylene carbonate, an additive for preventing gas generation, and a second additive. A sulfonyl group-containing first additive, vinylene carbonate, an antistatic additive, and a second additive that reduces the impedance and strengthens the SEI layer.

In addition, the additive for preventing gas generation in the disclosed additive is for reducing gas generation, which can be obtained from the reaction of one or more other additives, for example, a sulfonyl group-containing first additive. Electrolyte additive systems can be used to control gas evolution and provide some additives (e. G., ≪ RTI ID = 0.0 > For example, a gas generation preventing additive and an SEI forming additive).

In the disclosed salt system, less amount of LiPF ₆ can be used since the atmospheric salt is used. The decongestion is selected from the group which does not generate the racemic acid species during degradation. If atmospheric salts are involved, there is an unexpected result that less weight percent of at least one sulfonyl group-containing additive can be used because the concentration of the Lewis acid product formed from LiPF ₆ decomposition is reduced. When at least one sulfonyl group-containing additive is used in a lower weight percent, there is another unexpected advantage of being able to use a small amount of gas generation inhibitor in order to generally reduce the effect of high impedance with the gas generation inhibitor. Such a unique formulation forms a cell with low gas generation and reduced impedance, which is contrary to use with a gas generation preventing additive in which a sulfonyl group-containing additive is incorporated.

In use, the electrolyte formulation provides an improved cell. For example, the secondary battery can include an anode (also referred to as a cathode), a cathode (also referred to as an anode), a separator, and a nonaqueous electrolyte solution, for example, an electrolyte of the present disclosure. The secondary cell comprising the cells disclosed herein produces less gas, maintains a long cycle life over a wide temperature range, and improves power during cold start. In one example, an electrolyte formulation can be used in a lithium ion battery.

As provided above, the electrolyte formulation is a non-aqueous electrolyte solution and may include an additive system and a salt system. The additive system comprises a sulfonyl group-containing first additive, vinylene carbonate, an additive for preventing gas generation, and a second additive. In one example, the salt system may comprise LiPF ₆ and a coprecipitate. Further, the electrolyte solution includes a solvent system.

At least one sulfonyl group-containing first additive can reduce the loading of vinylene carbonate while maintaining good SEI development. For example, the first sulfonyl group-containing additive may be represented by the following formula (1): "

R ₁ -AR ₂ (One)

R ₁ and R ₂ independently represent an aryl group or an alkyl group which may be substituted with a halogen atom; An alkyl group or an aryl group which may be substituted with a halogen atom; Or used together to form a cyclic structure which may further contain an unsaturated bond with -A-, where "A" is represented by the formula selected from the following group:

(2)

(2)

(3)

(3)

(4) 및

(4) and

(5)

(5)

R ₁ and R ₂ may be an alkyl group having 1 to 4 carbon atoms, and specifically exemplified by a methyl group, an ethyl group, a propyl group, an isopropyl group, and a butyl group. Examples of the aryl group capable of substituting the alkyl group include a phenyl group, a naphthyl group and an anthranyl group, and among these, a phenyl group is more preferable. Examples of the halogen atom capable of substituting the alkyl group include a fluorine atom, a chlorine atom and a bromine atom. A plurality of such substituents may substitute an alkyl group, and simultaneous substitution by an aryl group and a halogen atom is possible.

The cyclic structure formed when R ₁ and R ₂ are bonded to each other and -A- is a 4-membered ring or more ring, and may contain a double bond or a triple bond. Examples of the bonding group formed by combining R ₁ and R ₂ with each other include --CH ₂ -, --CH ₂ CH ₂ CH ₂ -, --CH ₂ CH ₂ CH ₂ CH ₂ -, --CH ₂ CH _{2 CH 2 CH 2 CH 2 -} , --CH = CH--, --CH = CHCH 2 -, --CH 2 CH = CHCH 2 -, and -CH ₂ CH ₂ C≡CCH ₂ CH ₂ --to be. At least one hydrogen atom of these groups may be substituted by an alkyl group, a halogen atom, an aryl group, and the like.

A specific example of the molecule having "A " represented by the formula (2) includes a linear sulfite. Examples of the solvent include dimethyl sulfite, diethyl sulfite, ethyl methyl sulfite, methyl propyl sulfite, ethyl propyl sulfite, diphenyl sulfite, methyl phenyl sulfite, ethyl sulfite, dibenzyl sulfite, Fate, and benzyl ethyl sulfite; Cyclic sulfites such as ethylene sulfite, propylene sulfite, butylene sulfite, vinylene sulfite, phenylethylene sulfite, 1-methyl-2-phenylethylenesulfite, and 1-ethyl- Sulfite; And halides of such linear and cyclic sulfites

Specific examples of the molecule having "A" represented by the formula (3) include linear sulfones such as dimethylsulfone, diethylsulfone, ethylmethylsulfone, methylpropylsulfone, ethylpropylsulfone, diphenylsulfone, Ethyl sulfone, dibenzyl sulfone, benzyl methyl sulfone and benzyl ethyl sulfone: cyclic sulfone such as sulfolane, 2-methyl sulfolane, 3-methyl sulfolane, 2-ethyl sulfolane, 2,4-dimethylsulfolane, sulfolene, 3-methylsulfolene, 2-phenylsulfolane and 3-phenylsulfolane; And halides of such linear and cyclic sulfone.

Specific examples of the molecule having "A" represented by the formula (4) include linear sulfonic acid esters such as methylmethanesulfonate, ethylmethanesulfonate, propylmethanesulfonate, methylethanesulfonate, ethylethanesulfonate, Ethyl benzene sulfonate, propyl benzene sulfonate, phenyl methane sulfonate, phenyl ethane sulfonate, phenyl propane sulfonate, methyl benzyl sulfonate, ethyl benzyl sulfonate, propyl benzyl sulfonate, Benzyl methane sulfonate, benzyl ethane sulfonate and benzyl propane sulfonate; Cyclic sulfonic esters such as 1,3-propane sultone, 1,4-butane sultone, 3-phenyl-1,3-propane sultone and 4-phenyl-1,4-butane sultone; And halides of such linear and cyclic sulfonic acid esters.

Specific examples of the molecule having "A" represented by the formula (5) include sulfuric acid esters such as dimethyl sulfate, diethyl sulfate, ethyl methyl sulfate, methyl propyl sulfate, ethyl propyl sulfate, methyl phenyl sulfate, Phenyl propyl sulfate, benzyl methyl sulfate and benzyl ethyl sulfate; Cyclic sulfuric acid esters such as ethylene glycol sulfuric acid esters, 1,2-propanediol sulfuric acid esters, 1,3-propanediol sulfuric acid esters, 1,2-butanediol sulfuric acid esters, 1,3-butanediol sulfuric acid esters, 2,3 -Butanediol sulfuric acid ester, phenylethylene glycol sulfuric acid ester, methylphenyl ethylene glycol sulfuric acid ester, and ethylphenylethylene glycol sulfuric acid ester; And halides of such chain and cyclic sulfuric acid esters.

The molecule represented by formula (1) may be used alone in the electrolyte preparation, or two or more of such molecules may be used together.

The first sulfonyl group-containing additive represented by the formula (1) is exemplified by ethylene sulfite, dimethyl sulfite, sulfolane, sulfolene, and sulphone.

The amount of the first additive represented by the formula (1) contained in the organic solvent of the nonaqueous electrolyte solution is in the range of 0.05 to 100% by volume, 0.05 to 60% by volume, 0.1 to 15% by volume, or 0.5 to 2% by volume. Also, the first additive is in the range of 0.1 to 5 wt%, 0.1 to 3 wt%, or 0.1 to 1 wt% of the electrolyte preparation. Some of the first additives represented by the formula (1) are solid at room temperature, and these molecules are preferably used in an amount of not more than the saturation solubility with respect to the organic solvent used, more preferably not more than 60% by weight of the saturation solubility, Preferably 30% by weight or less. Thus, the additive is dissolved in an organic solvent over an expected use temperature range, for example, -30 캜 to + 60 캜, and is maintained in a solution form.

Vinylene carbonate is effective because the SEI is less soluble when the carbon-based anode is immobilized during the initial charge, and decomposition of the additive can be reduced. Vinylene carbonate may be added in an amount of 0.1 to 5% by weight of the electrolyte preparation. The amount of vinylene carbonate is determined by optimizing the ratio (VC: - A--) between the vinylene carbonate and the sulfonyl group-containing additive, to maintain the excellent SEI layer for improved cell cycling efficiency, Adjust to reduce loading of the bonnet. In one example, the ratio of VC: - A-- may be 1: 1. In another example, the ratio of VC: - A-- may be 2: 1.5. In another example, the ratio of VC: - A-- may be 2: 1.

Also, in an additive system, a gas-generating inhibitor may be added to the electrolyte to reduce gas formation over the life of the cell. In some instances, the antisegging agent may act through a path that deactivates the catalyst site in the cathode active material. While gas inhibitors generally increase the impedance of the cell, the disclosed electrolyte formulation provides improved and / or maintained impedance levels. Specifically, in this disclosure, the electrolyte formulation can reduce loading of the gas generation inhibitor combined with certain combinations of additives and salt systems and further reduce cell impedance.

In some example embodiments, the gas generation inhibitor may be present at less than 2.0 wt%, less than 1.5 wt%, or less than 1.0 wt% of the electrolyte formulation. For example, the gas generation inhibitor may be 1,5,2,4-dioxadithiane-2,2,3,3-tetraoxide (MMDS), prop-1-ene-1,3- ), Or 1,3-propane sultone. In another example, the gas generation inhibitor is 1,5,2,4-dioxadidiane-2,2,3,3-tetraoxide (MMDS), prop-1-en-1,3- ), Or 1,3-propane sultone.

In other examples, other gas generation inhibitors may be selected to reduce gas formation during cell lifetime. In one example, 1,3-propane sultone may be used. The gas generation inhibitor differs from the at least one sulfonyl group-containing first additive and is used together with the sulfonyl group-containing additive. The gas-generating agent and the sulfonyl group-containing additive may play different roles in the electrolyte.

Also, as provided above, the additive system may comprise a second additive. If a second additive is used, loading of the vinylene carbonate can be reduced while maintaining good SEI development for improved cell cycling efficiency. The second additive may be present at less than 5% by weight of the electrolyte formulation. For example, the second additive may be present at 0.1 to 5.0 wt%. In one embodiment, more than one second additive can be used to maintain good cycle life over a wide temperature range and further reduce impedance while suppressing gas. In one example, fluoroethylene carbonate (FEC) may be included as a second additive.

Electrolyte formulations include salt systems, in addition to additive systems. Salt systems include lithium salts and protons. Specifically, the salt system used in the non-aqueous electrolyte solution includes a lithium salt compounded with a coprecipitate, and the coprecipitate is less prone to form Lewis acid product by decomposition. These salt system, when combined with a lithium salt which does not exhibit the drawbacks of gongyeom LiPF _6, lithium salts, for example, the advantage of the LiPF ₆ is maintained. Choosing the complex salt combined with the lithium salt can solve PF ₅ and OPF ₃ obtained from the decomposition mechanism of strong Lewis acid, for example, LiPF ₆ .

The lithium salt may be selected to have beneficial properties similar to LiPF _6. For example, the lithium salt is _{LiPF 6, LiClO 4, LiBF 4} , LiCF 3 SO 3, LiN (CF 3 SO 2) 2, LiN (CF 3 CF 2 SO 2) 2, LiN (CFSO 2) (C 4 F ₉ SO ₂ ), and LiC (CF ₃ SO ₂ ) ₂ .

The pyrophosphate is a salt which is not easily decomposed; Salts that do not generate Lewis acid species during degradation and thereby reduce gas evolution through electrolyte degradation pathways; Salts that resist proton solvent or proton impurities in a solvent system; Salts which are inherently low in gas generation; And a salt having at least one of excellent conductivity at low temperature, and may not increase the impedance particularly in a low-temperature cell. In addition, the selected pyrophoris can have at least one of good conductivity over carbonaceous solvents, high solubility over temperature, and does not increase the impedance. For example, it may be chosen that the pyrophosphate produces or does not generate Lewis acid degradation during degradation. In one example, it can be chosen that the pyrophosphate produces or does not generate Lewis acid decomposition products during pyrolysis.

The pyrethroids are not limited as one example, and examples thereof include imide salts, triflate salts, organic borate salts, and fluorinated analogues thereof. Examples of the imide salt include bis (trifluoromethane) sulfonamide lithium salt (LiTFSI) and lithium bispentafluoroethanesulfonylimide (LiBETI). The triflate salt includes lithium trifluoromethane sulfonate (LiSO ₃ CF ₃ ). Organoborate salts include lithium bisoxalatoborate (LiBOB) and their fluorinated analogs, such as lithium difluorobioxalatoborate (LiFOB).

In one particular embodiment, the salt system includes LiPF ₆ and a sulfonamide lithium salt. As another non-limiting specific example, the salt systems include LiPF ₆ and LiTFSI.

The salt system may be 2.0M or less, or 0.5M to 1.5M or 0.5M to 1.0M. Communitivity can be present as a fraction of the total molar loading of the salt in the salt system. The decay may be less than 0.25M or 0.05M to 0.15M.

In addition to additive systems and salt systems, the electrolyte formulation may include an organic solvent system. Examples of the organic solvent include cyclic carbonates such as ethylene carbonate, propylene carbonate and butylene carbonate; Chain carbonates such as dimethyl carbonate, diethyl carbonate and ethyl methyl carbonate; Cyclic esters, for example, gamma -valerolactone; Chain esters such as methyl acetate and methyl propionate; Cyclic ethers such as tetrahydrofuran, 2-methyltetrahydrofuran and tetrahydrofuran; Chain ethers such as dimethoxyethane and dimethoxymethane; Cyclic phosphate esters such as ethylene methyl phosphate and ethyl ethylene phosphate; Chain phosphate esters such as trimethyl phosphate and triethyl phosphate; Its halide; Containing organic solvents other than those represented by the formula (1) by vinyl ethylene carbonate (VEC) and fluoroethylene carbonate (FEC), poly (ethylene glycol) diacrylate. These organic solvents may be used alone or in combination of two or more such solvents.

In one example, the electrolyte formulation is a mixture of at least one compound selected from the group consisting of a pyrophosphate containing LiPF ₆ and LiTFSI, ethylene carbonate (EC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), and propylene carbonate (ES) as a sulfonyl group-containing additive, vinylene carbonate (VC) and fluoroethylene carbonate (FEC) as further additives, and 1,3, - propane sultone (PS).

The secondary battery contains a positive electrode. In some instances, the positive electrochemically active material may be a lithium metal oxide. For example, LiCoO _{2, which} is lithium cobalt oxide, may be used as the positive electrochemically active material. In some other examples, the positive electrochemically active material may be a lithium transition metal oxo anion material selected from the following group.

(a) formula _{Li x (M '1-a} M''a) y (XO 4) z, Li x (M' 1-a M '' a) y (OXO 4) z , or Li _x (M _{'1 -a M '' a) y (} X 2 O 7) z, to have a conductivity at least 27 ℃ of about 10 ^-8 S / cm, M 'is a first row transition metal, X is phosphorus, sulfur, arsenic Wherein M " is at least one of boron, aluminum, silicon, vanadium, molybdenum and tungsten and M " is at least one of Group IIA, IIIA, IVA, VA, VIA, VIIA, VIIIA, IB, IIB, IIIB, IVB, VB, Y, and z are greater than 0 and x + y (1-a) x (formal valence or valence of M ') + ya x (M' Is a value such that z x (XO ₄ , X ₂ O ₇ , or the formal valency of the OXO ₄ group).

(b) formula _{(Li 1-a M ''} a) x M 'y (XO 4) z, (Li 1-a M''a) x M' y (OXO 4) z, or (Li _1-a M '' _a ) _x M ' _y (X ₂ O ₇ ) _z , at least about 10 ^-8 S / cm, wherein M' is the first thermal transition metal and X is phosphorus, Wherein M " is at least one of boron, aluminum, silicon, vanadium, molybdenum and tungsten and M " is at least one of Group IIA, IIIA, IVA, VA, VIA, VIIA, VIIIA, IB, IIB, IIIB, IVB, VB, X, y, and z are greater than 0 and x + y (1-a) x (the valence or valence of the formal moiety of M ') + ya x (M " Valence) has a value such that z x (formal valency of XO ₄ , X ₂ O ₇ , or OXO ₄ group).

(c) expression _{(Li ba) M '' a} ) x M 'y (XO 4) z, (Li ba) M''a) x M' y (OXO 4) z, or (Li _ba) M '' _{a) x} M 'has a conductivity in the _{y (X 2 O 7) z} , of at least about 10 ^-8 27 ℃ the S / cm M' is a first thermal transition metal, X is phosphorus, sulfur, arsenic, boron, Wherein M " is at least one of aluminum, silicon, vanadium, molybdenum and tungsten and M " is at least one of IIA, IIIA, IVA, VA, VIA, VIIA, VIIIA, IB, IIB, IIIB, IVB, VB, X, y, and z are greater than 0, and (b) x + y (1-a) x (M is a formal valence or valence) + ya x (M Quot; 'has a value such that z x (the formal valency of XO ₄ , X ₂ O ₇ , or OXO ₄ group).

In another example, the cathode active material is formula _{(Li 1 - x Z x)} MPO 4 (M is at least one of vanadium, chromium, manganese, iron, cobalt and nickel, Z is titanium, zirconium, niobium, aluminum, tantalum, Tungsten or magnesium and x is 0 to 0.05) or Li _{1 -x} MPO ₄ (M is selected from the group of vanadium, chromium, manganese, iron, cobalt and nickel and 0 ≦ x ≦ 1) Lithium transition metal phosphate compound.

In another example, the positive electrochemically active material is a lithium metal phosphate, such as lithium iron phosphate. The positive electrochemically active material may be present in powder or particulate form having a specific surface area of 5 m 2 / g, 10 m 2 / g, or greater than 15 m 2 / g, greater than 20 m 2 / g, or greater than 30 m 2 / g.

For example, the cathode may comprise a lithium metal phosphate. In one example, the lithium metal phosphate may be lithium iron phosphate LiFePO ₄ . In addition, LiFePO ₄ has an olivine structure and is produced in the form of very small, high specific surface area particles, which, even at elevated temperatures, can be produced in the presence of an oxidizing organic solvent, for example, an electrolyte, ) Stable Li-ion cell having a very high charge-discharge rate capability is obtained and shows excellent retention of lithium insertion and tear capacity during hundreds or thousands of high-speed cycles.

The secondary battery contains a negative electrode capable of inserting and dissociating lithium. For example, the anode may comprise graphite or a silicon / graphitic electrochemically active material. In one example, artificial graphite produced from soft (graphitizable) pitches of various origins processed by annealing and refined natural graphite when graphite carbonaceous material is used; Alternatively, graphite having various surface treatments at a pitch can be used, for example.

The method of manufacturing the positive electrode or the negative electrode by using the above active material is not limited. In one example, the electroactive material is prepared by mixing a binder, a conductive material, a solvent, etc. to form a slurry, coating the slurry on a substrate of the current collector, and then drying to produce an electrode. In addition, such electrode materials can be made into sheets or pellets by performing roll forming or compression molding.

The type of the binder used in the production of the electrode is not particularly limited as long as it is stable in the solvent used in the production of the electrode and in the electrolyte solution. As the binder, resin polymers such as polyethylene, polypropylene, polyethylene terephthalate, aromatic polyamide and cellulose; Rubber-like polymers such as styrene butadiene rubber, isoprene rubber, butadiene rubber and ethylene propylene rubber; Thermoplastic elastomeric polymers such as styrene butadiene styrene block copolymers and hydrogenated products thereof, styrene-ethylene-styrene block copolymers and their hydrides; Flexible resin polymers such as syndiotactic 1,2-polybutadiene, ethylene-vinyl acetate copolymers, and propylene- alpha -olefin (2 to 12 carbon atoms) copolymers; And fluorocarbon polymers such as polyvinylidene fluoride, polytetrafluoroethylene, and polytetrafluoroethylene-ethylene copolymers.

As the binder, a polymer preparation having an alkali metal ion (specifically, lithium ion) conductivity can be used. Such an ion conductive polymer preparation can be used in a complex system made of a polymer compound compounded with a lithium salt or an alkali metal salt.

The negative electrode material and the binder may be mixed in various ways. For example, the two particles may be mixed or the particles of the negative electrode material may entangled with the fibrous binder to form a mixture, or a layer of the binder may be deposited on the surface of the negative electrode particle. In one example, the mixing ratio of the binder to the cathode material may be from 0.1 to 30% by weight of the cathode material. In another example, the mixing ratio of the binder to the negative electrode material may be 0.5 to 10 wt% of the negative electrode material. If the binder is added in an amount exceeding 30 wt%, the internal resistance of the electrode is increased. If the binder is less than 0.1 wt%, the adhesion strength between the collector and the negative electrode material may be weak.

Upon mixing of the negative electrode material and the binder, the electrode material may be mixed together. As the conductive material used is not limited to a type, the conductive material can be a metal or a non-metal. For example, the metallic conductive material may be composed of a metallic element, for example, Cu or Ni. In another example, the non-metallic conductive material may be, for example, graphite, carbon black, acetylene black, and Ketjenblack. The average particle diameter of the conductive material may be 1 탆 or less.

In one example, the mixing ratio of the conductive material may be 0.1 to 30 wt% of the cathode material. In another example, the mixing ratio of the conductive material may be 0.5 to 15 wt% of the cathode material. If the mixing ratio of the conductive additive exceeds 0.1 wt%, it is possible to provide a sufficiently formed conductive path between the conductive materials in the electrode.

A mixture containing at least a negative electrode material and a binder may be applied to the current collector foil. The mixture can be applied to the current collector by means known to those skilled in the art. For example, if the mixture is a slurry, the slurry may be applied to the current collector by roller coating. In another example, when a solvent is contained in the mixture, the solvent may be removed by drying the solvent to prepare an electrode.

The anode containing the positive electroactive material has a specific surface area of greater than 5 m < 2 > / g measured using a nitrogen adsorption Brunauer-Emmet-Teller (BET) after concentration or calendering step. The anode has a thickness of less than 125 μm, for example, 50 to 125 μm, or 80 to 100 μm on one side of the current collector, and a pore volume fraction of about 40 to 70 vol%. The active material is generally about 10 to 20 mg / cm 2 and generally about 11 to 15 mg / cm 2.

The negative electrode active material is composed of powder or particles and has a specific surface area of more than about 2 m 2 / g, or more than 4 m 2 / g, or more than about 6 m 2 / g, as measured by nitrogen adsorption BET method. The negative electrode has a thickness of less than 75 占 퐉, for example, about 20 占 퐉 to 65 占 퐉, or about 40 占 퐉 to 55 占 퐉 and a pore volume fraction of 20 to 40% by volume on both sides of the current collector. The active material may be loaded generally at about 5 to 20 mg / cm 2, or about 4 to 5 mg / cm 2.

The manufacturing method of the anode is not particularly limited, and it can be noted that a method similar to the cathode described above can be used.

It is noted that the morphology or source material of the separation membrane used for the cell of the present disclosure is not particularly limited. The separator serves to separate the cathode and the anode in order to avoid such physical contact. In one example, the membrane may have high ion permeability and low electrical resistance. The material for the separator is preferably selected from those having excellent stability to the electrolyte solution and excellent liquid retentivity. For example, a nonwoven fabric or a porous film made of a polyolefin, for example, polyethylene and polypropylene is used as a separator, and an electrolyte solution is injected into the separator.

The method of producing a nonaqueous electrolyte solution cell using such a nonaqueous electrolyte solution, a negative electrode, a positive electrode, an outer container, and a separation membrane may be selected from those generally used without particular limitations. The non-aqueous electrolyte cell of the present disclosure may include a gasket, a sealing plate, and such a non-aqueous electrolyte solution, a cathode, an anode, an outer can or pouch material, and a separator. In one example, the nonaqueous electrolyte solution cell of the present disclosure can be fabricated into a pouch because of less gas evolution of the electrolyte over a wide temperature range.

The cells described herein demonstrate that they have desirable properties over a wide temperature range that may be expected to operate the cell. For example, the cell may operate at -30 캜 to + 60 캜. In addition, a cell with the disclosed electrolyte formulation reduces gas generation and reduces impedance. The low impedance of the cell is important because it increases performance at low temperatures and increases battery life. Preferred and unexpected properties include organic solvents, sulfonic group-containing first additives, vinylene carbonate, antistatic agents, a second additive to reduce vinylene carbonate loading, and a salt system in which the lithium salt is combined with a coprecipitate Lt; RTI ID = 0.0 > Lewis < / RTI > acid decomposition products. The amount of vinylene carbonate can be optimized by optimizing the ratio between the sulfonyl group-containing additive and the vinylene carbonate and also by reducing the loading of the vinylene carbonate while maintaining a good SEI layer for improved cell cycling efficiency .

Generally, the thickened electrode layer (and increased active material loading) increases the total capacitance to the cell. However, when the layer becomes thick, the impedance of the electrode also increases. Unlike the prior art, high capacities and thick layers may be used in low impedance (high speed) cells according to one or more embodiments. The use of a high specific surface area active material provides the desired capacity without increasing the impedance to an undesirably high level while maintaining a suitable pore volume.

In terms of the battery container, if the generation of gas of the electrolyte preparation is reduced, it can be used as a pouch and other structures.

The choice of organic solvent in the electrolyte is important for impedance reduction. In some embodiments, it is preferred that the electrolyte does not contain gamma -butyrolactone, because gamma -butyrolactone can perform reduced oxidation at the cathode upon battery charging (Petibon et al, Journal of the Electrochemical Society , 160 (1) A117-A124 (2013)). The obtained decomposition product may cause clogging of the separation membrane. Then, by increasing the surface resistance of the cathode by clogging and increasing the impedance at the anode, the capacity is considerably lost during cycling.

Further, when the additive represented by the formula (1) is used in addition to vinylene carbonate (VC) in the non-aqueous organic electrolyte, a stable and low-impedance lithium ion battery is formed. Without being bound by any theory, it can be seen that such an additive reacts with the anode to form an SEI to reduce the impedance, and the SEI has a higher ionic conductivity than the ionic conductivity with the electrolyte without the additive. In addition, VC is effective in fixing the carbon-based anode during initial charging. The VC prevents dissolution of the additive by dissolving the SEI less.

The SEI arises from the thermodynamic instability of the graphitic anodes in the organic electrolyte. First, the cell is charged (which is referred to as formation), and then graphite reacts with the electrolyte. This forms a porous pinning layer (referred to as the solid electrolyte interface (SEI) which protects the cathode from further attack), regulates the charge rate and limits the current. This reaction also rarely consumes lithium. At high temperatures, or as the cell progresses to zero charge ("deep cycling"), the SEI can be partially dissolved in the electrolyte. At high temperatures, the electrolyte decomposes to promote side reactions, potentially leading to thermal runaway. When the temperature is reduced, another protective layer is formed, but a large amount of lithium is consumed, and the loss of the cap can be large. Thus, the stability of SEI at high temperature is important to increase the lifetime of the cell with one advantage of the cell described herein. In addition, the cells described herein reduce gas generation over a wide temperature range.

However, when the SEI layer becomes too thick, it becomes a barrier to the actual lithium ion and increases the impedance. The thickness of the SEI layer affects power performance and is important in electric vehicles.

The method of defining the battery impedance is to measure the region-specific impedance. The impedance value may be determined for the entire cell or for a specific junction, for example, an anode or a cathode. The area specific impedance (ASI) is the impedance of the device normalized to the surface area and is defined as the value measured at 1 kHz (Ω) by the LCZ meter or the frequency response analyzer multiplied by the surface area (㎠) of the opposite electrode do. This measurement is performed by applying a small (e. G., 5mV) sinusoidal voltage to the cell and measuring the resulting current response. The obtained response can be described by the in-phase component and the abnormal component. The in-phase component (real or resistive) component of the impedance of 1 kHz multiplied by the surface area (cm 2) of the opposite electrode provides a region-specific impedance. The region-specific impedance can be used to determine the impedance at the anode or cathode.

In one form, the secondary battery is used in a battery system that operates as a microhybrid cell. For example, when stopping at a traffic signal, the microhybrid battery (or vehicle having a start-stop feature) can stop the vehicle by the internal combustion engine of the vehicle, It is saved. When the driver releases the brakes and presses the gas pedal, the engine starts up again quickly and the vehicle moves forward. While the early-generation micro-hybrid focuses on re-engineer- ing smooth engines, next-generation systems are expected to restore brake energy as a direction toward even greater fuel economy. Conventional lead acid microhybrid battery technology has some design constraints because it can not charge very quickly and most of the vehicle's brake energy is still lost. Batteries with lithium ion chemistry are positioned to support the next generation of microhybrid systems as the fuel economy is improving at a faster rate because of the very fast filling rate.

The microhybrid battery can be used as a starter battery of an automobile engine. Near the engine and under the hood, there is often no room for a large thermal management circuit. Therefore, the battery needs to operate without heat input to the engine at an ambient temperature cooled down to -30 占 폚. In addition, the battery needs to operate for extended periods of time at the operating temperature of the automotive engine (60 < 0 > C or less) without external cooling. Conventional lithium ion batteries have a high impedance at low temperatures and have a reduced ability to operate the engine. Further, the design of increasing the power at a low temperature in a lithium ion battery often shortens the lifetime at a high temperature. Although the lead acid battery improves the low temperature starting ability, it has a short lifetime unlike the lithium ion battery for the start-stop application.

The nonaqueous electrolyte solution cell of the present disclosure has excellent low temperature characteristics and long life stability, and excellent cycle characteristics when used in a microhybrid cell system. This technology has been particularly successful in microhybrid lithium-ion batteries in starter batteries, which can increase the low-temperature power of the battery and drive the vehicle engine even in the worst-case scenario. In addition, the extended service life of the battery in a high temperature environment is important because a typical package of the starter battery is located in an engine compartment of a temperature higher than the normal room temperature during vehicle operation. In addition, the nonaqueous electrolyte solution of the cell of the present invention generates a small amount of gas over a temperature range.

The present application will be explained in more detail with reference to the following examples. The above-described materials, amounts used, ratios, manipulations, and the like can be changed without departing from the spirit of the present invention. Therefore, the scope of the present invention is not limited to the specific examples described below. The disclosed electrolyte preparation can be applied to any form of battery, for example, a prism, a button cell, a can, a pouch, and the like.

Examples of electrolyte preparations are provided below. Electrolyte formulations provide less gas generation over a wide temperature range. An electrolyte preparation with reduced gas generation at a wide temperature is an example of the electrolyte described in this application.

Example  1: Electrolyte preparation

The electrolyte formulation of the example according to the present disclosure was prepared by mixing 1.0 M LiPF ₆ , 0.15 M LiTFSI, 40 vol% EC, 45 vol% EMC, 10 vol% DEC, 5 vol% PC, 1.5 wt% ES, 1 wt.% VC and 1.5 wt.% PS.

The electrolyte preparations are compared to the reference electrolyte preparations in Figures 1 to 10 described below. Electrolyte formulations exhibit improved properties during low and high temperature experiments compared to reference electrolyte formulations

The first reference electrolyte formulation comprises 1.15 M LiPF ₆ , 30 vol% EC, 55 vol% EMC, 10 vol% DEC, 5 vol% PC, 1 wt% ES, and 2 wt% VC. The first contrast electrolyte preparation contains the first sulfonyl group-containing additive, ES, but does not provide the gas generating additive or salt solution of the present application.

The second comparative electrolyte formulation contained 1.15 M LiPF ₆ , 35% by volume EC, 40% by volume EMC, 20% by volume DMC, 5% by volume PC, 2.5% by weight VC, 0.2% by weight of triphenylphosphite (TPPI) 2 wt% PS. The second contrast electrolyte formulation contains PS but does not provide a first sulfonyl group containing additive or salt system.

The electrolytes of the above example and the control electrolyte preparations can be referred to the following description of the drawings. The cell may be constructed using a lithium iron phosphate (LFP) cathode having a graphite anode or a nickel cobalt metal (NCM) cathode having a graphite anode. Other cathode / anode combinations may be possible.

Referring to FIG. 1, initial capacity losses are shown for the formation and quantification of cells with a lithium iron phosphate (LFP) cathode and a graphite anode. The LFP / graphite cell was fabricated with the electrolyte formulation described in Example 1 and another LFP / graphite cell was fabricated with the first contrast electrolyte formulation. The initial capacity loss for the newly reduced gas generating electrolyte during formation 101 and quantification 102 shows improved initial capacity loss compared to the first control electrolyte formulation at formations 103 and quantities 104. [

Referring to FIG. 2, there is shown the initial capacity loss for the formation and quantification of a cell having a nickel cobalt manganese (NCM) cathode and a graphite anode. The NCM / graphite cell was fabricated with the electrolyte formulation described in Example 1 and another NCM / graphite cell was fabricated with the second control electrolyte formulation. The initial capacity loss for the newly reduced gas generating electrolyte 201 shows improved initial capacity loss as compared to the second control electrolyte preparation 202.

Thus, the initial capacity loss data indicates that the new electrolyte formulation provides excellent initial capacity loss as compared to the first and second reference electrolyte formulations under various experimental conditions, as shown in FIGS. 1 and 2.

Referring to FIG. 3, the AC resistance / DC resistance (ACR / DCR) impedance between the new electrolyte preparation and the second reference electrolyte preparation in the LFT / graphite cell is parity. The new electrolyte formulation exhibits similar or lower impedance measurements than both DCR (square) and ACR (diamond) compared to the first control electrolyte.

Referring to FIG. 4, the ACR impedance of the cell having the electrolyte in Example 1 is shown. Compared to the second control electrolyte 402 for a cell having an NCM cathode and a graphite anode, the new electrolyte formulation 401 exhibits an improved ACR impedance in the NCM / graphite cell.

Thus, as shown in Figures 3 and 4, the new electrolyte formulation maintains / decreases the impedance.

Referring to FIGS. 5A and 5B, the hybrid pulse power capability (HPPC) experiment is shown at 23 DEG C with the 1 second pulse power shown in FIG. 5A and the 10 second pulse power shown in FIG. 5B. The new electrolyte preparation 501 shows a reduction in DCR during the HPPC experiment compared to the first reference electrolyte preparation 502. All electrolytes were used in LFP / graphite cells.

Referring to FIGS. 6A and 6B, a hybrid pulse power capability (HPPC) experiment is shown at -20 DEG C at 1 second pulse power shown in FIG. 6A and 10 second pulse power shown in FIG. 6B. The new electrolyte formulation 601 shows a large reduction in DCR during HPPC experiments compared to the first reference electrolyte formulation 602. [ Thus, new electrolyte preparations exhibit improved performance at low temperatures. All electrolytes were used in LFP / graphite cells.

Referring to Figure 7, the power at 70% state of charge (SOC) during cold start at -30 [deg.] C is shown. The new electrolyte preparation 701 (solid line) indicated by the upper arrow represents increased power compared to the first reference electrolyte preparation 702 (dotted line) indicated by the lower arrow. Thus, new electrolyte formulations exhibit improved performance at low temperatures.

Referring to Fig. 8, the power during NC-start of NCM / graphite cells at -30 [deg.] C is shown. The new electrolyte formulation 801 shows a cold start power increase of about 20% compared to the second control electrolyte formulation 802. Thus, new electrolyte formulations exhibit improved performance at low temperatures.

Referring to Figure 9, the cycle life of an NCM cathode / graphite anode cell is shown. The new electrolyte, black line 901, exhibits improved cycle life compared to second contrast electrolyte gray line 902. Thus, new electrolytic formulations can extend cycle life.

Referring to Fig. 10, the gas volume after storage at 55 占 폚 is shown in the LFP / graphite cell. New electrolyte preparations 1001,1002,1003 can be used for pouch construction, for example, over time time 0, time 1, and time 2 for use with the second reference electrolyte preparation 1004,1005,1006 It provides a level of gas generation in series with other acceptable electrolytes. Thus, new electrolyte formulations provide less gas evolution.

The disclosed electrolyte preparations include additive systems and salt systems that provide low gas generation, wide temperature cycling systems. In one example, the disclosed formulation comprises a non-aqueous electrolyte solution comprising a sulfonyl group, an antistag agent, a second additive and a salt system. The gas-generation inhibitor, a salt system containing a coprecipitate can reduce gas production of the sulfonyl group-containing additive while reducing LiPF ₆ , and the coprecipitate will be less prone to generate Lewis acid decomposition products. Also, in some instances, a second additive, e. G., FEC, can be used to reduce the impedance and enhance the SEI layer.

As briefly described above, new electrolyte formulations can be used in a variety of different cell structures, including pouch structures. For example, the anti-gassing properties of the disclosed formulation can specifically improve its use in the pouch.

An exemplary pouch structure for use with the disclosed electrolyte formulation is shown with reference to FIG. The pouch includes an anode and a cathode sheet and seals around the anode and the cathode. For example, the pouch material may comprise a laminated layer comprising at least one of polyethylene, nylon and aluminum foil. In one example, the internal components can be hermetically sealed within an enclosure made of a pouch material. Other suitable materials can be used to seal the internal components of the cell.

The diagram of Figure 11 illustrates a wide variety of exemplary prismatic battery cells 200 including collection taps 304a and 304b, extension taps 308a and 308b, weld sections 604a and 604b, and strips 504a and 504b. Lt; / RTI > The pouch structure may be susceptible to rupture if a large amount of gas is generated in the cell. The use of the electrolyte formulation disclosed in the pouch provides for reduced gas generation, improved / sustained impedance, improved low temperature starting power and use over a wide temperature range.

The above description is to be understood in all respects as illustrative and not in any way limiting. While the invention has been illustrated and described with reference to a preferred embodiment, it will be understood that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

The corresponding structures, materials, acts and equivalents of all means or steps and functional elements within the scope of the following claims are to be accorded the fullest permutation that follows, including any structure, material, or action for performing a function with any other claimed element It is intended.

Finally, the articles, systems, and methods described above are embodiments of this disclosure-non-limiting example in which a number of variations and extensions are contemplated. Accordingly, the present disclosure includes all new and unambiguous combinations and subcombinations of articles, systems and methods disclosed herein, and any and all equivalents thereof.

Claims (15)

A negative electrode capable of inserting and dissociating lithium;
A positive electrode comprising an oxo anion electroactive material which is a lithium transition metal;
Separation membrane; And
Wherein the non-aqueous electrolyte solution comprises a non-aqueous electrolyte solution,
A lithium salt present in 0.85 to 1.5 M and a quaternary salt present in 0.05 M to 0.25 M, wherein the quaternary salt does not generate Lewis acid decomposition products;
Additive system; The additive system comprises:
Gas generation inhibitor,
At least one sulfonyl group-containing first additive represented by formula (1):
R ₁ -AR ₂ (One)
(Wherein R ₁ and R ₂ independently represent an alkyl group which may be substituted with an aryl group or a halogen atom, an aryl group which may be substituted with an alkyl group or a halogen atom, or an aryl group which may be substituted by -A- together with an unsaturated bond "A" is represented by the formula selected from the following group:

(2)

(3)

(4) and

(5)
A second additive, and
Vinylene carbonate; And
A secondary battery comprising at least one organic solvent, wherein the non-aqueous electrolyte solution does not contain? -Butyrolactone.
The method according to claim 1,
Wherein the sulfonyl group-containing first additive is present at 0.1 wt% to 5 wt% of the electrolyte formulation, and the vinylene carbonate is present at 0.1 wt% to 5 wt% of the electrolyte formulation.
The method according to claim 1,
The gas generation inhibitor may be 1,5,2,4-dioxadidiane-2,2,3,3-tetraoxide (MMDS), prop-1-en-1,3- , 3-propane sultone.
The method according to claim 1,
Wherein the gas generation inhibitor is present in an amount of 2% by weight or less.
The method according to claim 1,
Wherein the atmospheric salt is selected from one of the classes of salts comprising an imide salt, a triflate salt, or an organic borate salt, or wherein the at least one of the at least two classes of salts is bis (trifluoromethane) sulfonamide lithium salt (LiTFSI).
The method according to claim 1,
The lithium salt is _{LiPF 6, LiClO 4, LiBF 4} , LiCF 3 SO 3, LiN (CF 3 SO 2) 2, LiN (CF 3 CF 2 SO 2) 2, LiN (CFSO 2) (C 4 F 9 SO 2 ), and LiC (CF ₃ SO _{2) 2} , Or wherein the lithium salt is present at 1.0 M and the conjugate is present at 0.05 to 0.2 M.
The method according to claim 1,
Wherein the second additive is fluoroethylene carbonate and is present at 1% by weight.
The method according to claim 1,
The organic solvent may be at least one selected from the group consisting of ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate, gamma -valerolactone, methyl acetate, Tetrafluoroethane, and the like), tetrahydrofuran, 2-methyltetrahydrofuran and tetrahydropyran, dimethoxyethane and dimethoxymethane, ethylene methyl phosphate and ethyl ethylene phosphate, trimethyl phosphate and triethyl phosphate, halides thereof, vinyl ethylene carbonate VEC), and at least one of fluoroethylene carbonate (FEC), poly (ethylene glycol) diacrylate, and combinations thereof, or the organic solvent includes ethylene carbonate, ethyl methyl carbonate, diethyl A mixture of a carbonate and a propylene carbonate.
The method according to claim 1,
Wherein the secondary battery is contained in the pouch.
The method according to claim 1,
Wherein the negative electrode is a natural graphite compound of carbonaceous material comprising non-graphite carbon, artificial graphite, or silicon or silicon oxide.
The method according to claim 1,
Wherein the anode comprises a lithium transition metal oxide.
The method according to claim 1,
Wherein the organic solvent mixture comprises a secondary battery comprising 30 vol% of ethylene carbonate, 55 vol% ethyl methyl carbonate, 10 vol% diethyl carbonate, and 5 vol% propylene carbonate. .
A lithium salt present at 0.85 to 1.5 M and a quasi-salt present at 0.05 M to 0.25 M, said salt being a salt system that is less prone to generate Lewis acid decomposition products; And
Additive system;
Said additive system comprising:
At least one sulfonyl group-containing first additive represented by formula (1):
R ₁ -AR ₂ (One)
(Wherein R ₁ and R ₂ independently represent an alkyl group which may be substituted with an aryl group or a halogen atom, an aryl group which may be substituted with an alkyl group or a halogen atom, or an aryl group which may be substituted by -A- together with an unsaturated bond "A" is represented by the formula selected from the following group:

(2)

(3)

(4) and

(5)
Gas generation inhibitor,
A second additive, and
Vinylene carbonate;
Wherein the electrolytic solution is a water-soluble polymer.
14. The method of claim 13,
Solvent system, or the first additive is present in an amount of 0.1 to 5 wt%, the gas generation inhibitor is present in an amount of 2 wt% or less, the second additive is present in an amount of 0.1 wt% to 5 wt% And the vinylene carbonate is present in an amount of 0.1 wt% to 5 wt%.
The method according to claim 1,
Wherein the second additive is present in an amount of up to 5% by weight of the electrolyte formulation.

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