JP7347768B2 - Non-aqueous electrolytes for batteries and lithium secondary batteries - Google Patents

Description

The present disclosure relates to a non-aqueous electrolyte for batteries and a lithium secondary battery.

In recent years, lithium secondary batteries have been widely used as power sources for electronic devices such as mobile phones and notebook computers, electric vehicles, and power storage. Particularly recently, there has been a rapid increase in demand for batteries with high capacity, high output, and high energy density that can be installed in hybrid vehicles and electric vehicles.
BACKGROUND ART Conventionally, various additives have been incorporated into non-aqueous electrolytes of batteries such as the above-mentioned lithium secondary batteries.
For example, attempts have been made to improve battery performance by incorporating various cyclic sulfate ester compounds into the non-aqueous electrolyte of lithium secondary batteries (see, for example, Patent Documents 1 to 6).

Japanese Patent Application Publication No. 10-189042 Japanese Patent Application Publication No. 2003-151623 Japanese Patent Application Publication No. 2003-308875 Japanese Patent Application Publication No. 2004-22523 Japanese Patent Application Publication No. 2005-011762 International Publication No. 2012/053644

However, there are cases where it is required to further suppress the increase in battery resistance during storage.
An object of the first aspect of the present disclosure is to provide a battery in which an increase in battery resistance during storage is suppressed.
An object of the second aspect of the present disclosure is to provide a non-aqueous electrolyte for batteries that can suppress an increase in battery resistance during storage.

Means for solving the above problems include the following aspects.
<1> A battery comprising a positive electrode, a negative electrode, and a non-aqueous electrolyte,
The non-aqueous electrolyte contains an additive S containing a sulfur atom and an oxygen atom,
When measuring the narrow spectrum of sulfur atoms on the surface of the negative electrode by X-ray photoelectron spectroscopy and performing peak separation on the S2p orbit, 168. A battery in which the area ratio of peak 1 observed in the region of 4 eV to 171.1 eV is 10 to 150.

<2> The additive S is
The following partial structure (S1) and
At least one of the following partial structure (S2) and the following partial structure (S3),
The battery according to <1>, including:

In the partial structure (S1), the partial structure (S2), and the partial structure (S3), *11, *12, *21, *22, *31, and *32 each represent the bonding position with the carbon atom. .

<3> The battery according to <1> or <2>, wherein the additive S is composed of two or more types selected from the group consisting of compounds containing sulfur atoms and oxygen atoms.

<4> The additive S is
The following compound (1) and
At least one of the following compound (2), the following compound (3), and the following compound (4),
The battery according to any one of <1> to <3>.

In compound (1), R ¹¹ to R ¹⁴ each independently represent a hydrogen atom, a hydrocarbon group having 1 to 6 carbon atoms, a group represented by formula (1a), or a group represented by formula (1b). represents. In formula (1a) and formula (1b), * represents the bonding position.
In compound (2), R ²¹ to R ²⁶ each independently represent a hydrogen atom, a fluorine atom, a hydrocarbon group having 1 to 3 carbon atoms, or a fluorinated hydrocarbon group having 1 to 3 carbon atoms.
In compound (3), R ³¹ to R ³⁴ each independently represent a hydrogen atom, a fluorine atom, a hydrocarbon group having 1 to 3 carbon atoms, or a fluorinated hydrocarbon group having 1 to 3 carbon atoms.
In compound (4), R ⁴¹ to R ⁴⁴ each independently represent a hydrogen atom, a hydrocarbon group having 1 to 6 carbon atoms, a group represented by formula (4a), or a group represented by formula (4b). represents. In formula (4a) and formula (4b), * represents the bonding position.

<5> If the average number of oxygen atoms directly bonded to one sulfur atom in the additive S is the average number of S-O bonds in the additive S, then the average S-O bond in the additive S is The battery according to any one of <1> to <4>, which has a number of 3.10 to 3.90.
<6> The negative electrode includes a negative electrode active material,
The battery according to any one of <1> to <5>, wherein the negative electrode active material contains graphite.
<7> The battery according to any one of <1> to <6>, which is a lithium secondary battery.

<8> The following compound (1) and
At least one of the following compound (2), the following compound (3), and the following compound (4),
A nonaqueous electrolyte for batteries containing.

In compound (1), R ¹¹ to R ¹⁴ each independently represent a hydrogen atom, a hydrocarbon group having 1 to 6 carbon atoms, a group represented by formula (1a), or a group represented by formula (1b). represents. In formula (1a) and formula (1b), * represents the bonding position.
In compound (2), R ²¹ to R ²⁶ each independently represent a hydrogen atom, a fluorine atom, a hydrocarbon group having 1 to 3 carbon atoms, or a fluorinated hydrocarbon group having 1 to 3 carbon atoms.
In compound (3), R ³¹ to R ³⁴ each independently represent a hydrogen atom, a fluorine atom, a hydrocarbon group having 1 to 3 carbon atoms, or a fluorinated hydrocarbon group having 1 to 3 carbon atoms.
In compound (4), R ⁴¹ to R ⁴⁴ each independently represent a hydrogen atom, a hydrocarbon group having 1 to 6 carbon atoms, a group represented by formula (4a), or a group represented by formula (4b). represents. In formula (4a) and formula (4b), * represents the bonding position.

According to the first aspect of the present disclosure, a battery is provided in which an increase in battery resistance during storage is suppressed.
According to the second aspect of the present disclosure, a nonaqueous electrolyte for a battery is provided that can suppress an increase in battery resistance during storage.

1 is a schematic perspective view showing an example of a laminate type battery, which is an example of a battery according to a first aspect of the present disclosure. 2 is a schematic cross-sectional view in the thickness direction of a laminated electrode body housed in the laminated battery shown in FIG. 1. FIG. FIG. 2 is a schematic cross-sectional view showing an example of a coin-type battery, which is another example of the battery according to the first aspect of the present disclosure.

In this specification, a numerical range expressed using "~" means a range that includes the numerical values written before and after "~" as lower and upper limits.
In this specification, if there are multiple substances corresponding to each component in the composition, unless otherwise specified, the amount of each component in the composition refers to the total amount of the multiple substances present in the composition. means.

[First aspect; battery]
A battery according to a first aspect of the present disclosure includes a positive electrode, a negative electrode, and a non-aqueous electrolyte,
The non-aqueous electrolyte contains an additive S containing a sulfur atom and an oxygen atom,
When measuring the narrow spectrum of sulfur atoms on the surface of the negative electrode by X-ray photoelectron spectroscopy and performing peak separation on the S2p orbit, 168.4 eV for peak 2 observed in the region of 166.3 eV to 169.0 eV. The area ratio of peak 1 observed in the region of ~171.1 eV (hereinafter also referred to as "area ratio [peak 1/peak 2]") is 10 to 150.

According to the battery according to the first aspect, an increase in battery resistance during storage is suppressed.
The effect of suppressing the increase in battery resistance during storage is particularly remarkable with respect to battery resistance under low temperature conditions (for example, -20°C).

In this specification, the concept of "increase in battery resistance during storage is suppressed" includes a state in which battery resistance increases during storage but the degree of increase is suppressed, and a state in which battery resistance changes during storage. This includes all conditions in which the battery resistance is rather reduced during storage.

Although it is not clear why the above effects are achieved in the battery according to the first aspect, in the battery according to the first aspect, a film caused by the additive S is formed on the surface of the negative electrode, and this film is This is thought to be due to the fact that the resistance does not increase much during storage of the battery, or the resistance is further reduced.
This property of the film is thought to be achieved by the film containing two or more types of sulfur atoms with different electronic states in a specific ratio.

<Area ratio [Peak 1/Peak 2]>
In the battery according to the first aspect, it is satisfied that the area ratio [peak 1/peak 2] is 10 to 150. This suppresses an increase in battery resistance during storage.
Peak 1 is a peak observed in the region of 168.4 eV to 171.1 eV when measuring the narrow spectrum of sulfur atoms on the surface of the negative electrode by X-ray photoelectron spectroscopy and performing peak separation on the S2p orbit. .
Peak 1 is considered to be a peak derived from the partial structure represented by SO ₄ (specifically, partial structure (S1) below).
Peak 2 is a peak observed in the region of 166.3 eV to 169.0 eV when measuring the narrow spectrum of sulfur atoms on the surface of the negative electrode by X-ray photoelectron spectroscopy and performing peak separation on the S2p orbit. .
Peak 2 is considered to be a peak derived from the partial structure represented by SO ₃ (specifically, the following partial structure (S2) or the following partial structure (S3)).
The area ratio [peak 1/peak 2] of 10 to 150 means that both the partial structure (S1) and at least one of the partial structure (S2) and the partial structure (S3) are present on the surface of the negative electrode. This is thought to mean that a film containing a specific ratio of

In the partial structure (S1), the partial structure (S2), and the partial structure (S3), *11, *12, *21, *22, *31, and *32 each represent the bonding position with the carbon atom. .
The partial structure (S1) is part of the sulfate structure, the partial structure (S2) is part of the phosphonate structure, and the partial structure (S3) is part of the sulfite structure.

As described above, in the battery according to the first embodiment, the area ratio [Peak 1/Peak 2] is 10 to 150.
From the viewpoint of more effectively achieving the effect of the battery according to the first aspect (that is, the effect of suppressing an increase in battery resistance during storage), the area ratio [peak 1/peak 2] is preferably 10 to 100. It is preferably from 10 to 80, even more preferably from 10 to 60.

Each element of the battery according to the first aspect will be explained below.

<Nonaqueous electrolyte>
The non-aqueous electrolyte provided in the battery according to the first aspect contains an additive S containing sulfur atoms and oxygen atoms.
In the battery according to the first aspect, it is thought that a film derived from the additive S is formed on the negative electrode.

(Additive S)
The additive S may be composed of only one type selected from the group consisting of compounds containing a sulfur atom and an oxygen atom, or two or more types selected from the group consisting of compounds containing a sulfur atom and an oxygen atom. It may be composed of.
In any case, from the viewpoint of easily achieving an area ratio [Peak 1/Peak 2] of 10 to 150, the additive S has a partial structure (S1), a partial structure (S2), and a partial structure ( S3).

From the viewpoint of easily achieving the area ratio [Peak 1/Peak 2] of 10 to 150, the additive S may be composed of two or more types selected from the group consisting of sulfur atoms and compounds containing sulfur atoms. preferable.

The content of the additive S (if the additive S consists of two or more compounds, the total content of the two or more compounds) is 0.001% by mass to 10% by mass based on the total amount of the non-aqueous electrolyte. It is preferably 0.001% by mass to 5% by mass, even more preferably 0.001% to 3% by mass, even more preferably 0.01% to 3% by mass, It is more preferably 0.1 to 3% by weight, even more preferably 0.1 to 2% by weight, and particularly preferably 0.1 to 1% by weight.

From the viewpoint of easily achieving the area ratio [Peak 1/Peak 2] of 10 to 150, the additive S is the following compound (1), the following compound (2), the following compound (3), and the following compound. It is more preferable to consist of at least one of (4).

When additive S consists of compound (1) and at least one of compound (2), compound (3), and compound (4), the content of additive S is compound (1), This corresponds to the total content of compound (2), compound (3), and compound (4).
The preferable range of the content of the additive S is as described above.

When additive S consists of compound (1) and at least one of compound (2), compound (3), and compound (4), the amount of compound (2) relative to the content mass of compound (1) , compound (3), and compound (4) (i.e., content mass ratio [(compound (2) + compound (3) + compound (4))/compound (1)]) is 0. It is preferably from .1 to 10, more preferably from 0.2 to 5.0, and even more preferably from 0.3 to 3.0.

Each of compounds (1) to (4) will be explained below.

-Compound (1)-

In compound (1), R ¹¹ to R ¹⁴ each independently represent a hydrogen atom, a hydrocarbon group having 1 to 6 carbon atoms, a group represented by formula (1a), or a group represented by formula (1b). represents. In formula (1a) and formula (1b), * represents the bonding position.

In compound (1), the hydrocarbon group having 1 to 6 carbon atoms represented by R ¹¹ to R ¹⁴ may be a straight chain hydrocarbon group or a hydrocarbon group having a branched and/or ring structure. It may be.
The hydrocarbon group having 1 to 6 carbon atoms represented by R ¹¹ to R ¹⁴ is preferably an alkyl group, an alkenyl group, or an alkynyl group, more preferably an alkyl group or an alkenyl group, and particularly preferably an alkyl group.
The number of carbon atoms in the hydrocarbon group having 1 to 6 carbon atoms represented by R ¹¹ to R ¹⁴ is preferably 1 to 3, more preferably 1 or 2, and particularly preferably 1.

Specific examples of compound (1) include the following compounds (1-1) to (1-4), but compound (1) is not limited to these specific examples.
Among these, compounds (1-1) to (1-3) are particularly preferred.

When the additive S contained in the nonaqueous electrolyte consists of compound (1) and at least one of compound (2), compound (3), and compound (4), the additive S of compound (1) The content is preferably 0.001% by mass to 10% by mass, more preferably 0.001% by mass to 5% by mass, and 0.001% by mass to 3% by mass, based on the total amount of the nonaqueous electrolyte. is more preferably 0.01% by mass to 3% by mass, even more preferably 0.1% to 3% by mass, still more preferably 0.1% to 2% by mass, and even more preferably 0.01% to 3% by mass. Particularly preferred is 1 to 1% by weight.

-Compound (2)-

In compound (2), R ²¹ to R ²⁶ each independently represent a hydrogen atom, a fluorine atom, a hydrocarbon group having 1 to 3 carbon atoms, or a fluorinated hydrocarbon group having 1 to 3 carbon atoms.

In compound (2), the hydrocarbon group having 1 to 3 carbon atoms represented by R ²¹ to R ²⁶ may be a straight chain hydrocarbon group or a hydrocarbon group having a branched and/or ring structure. It may be.
The hydrocarbon group having 1 to 3 carbon atoms represented by R ²¹ to R ²⁶ is preferably an alkyl group, an alkenyl group, or an alkynyl group, more preferably an alkyl group or an alkenyl group, and particularly preferably an alkyl group.
The number of carbon atoms in the hydrocarbon group having 1 to 3 carbon atoms represented by R ²¹ to R ²⁶ is preferably 1 or 2, and more preferably 1.

In compound (2), the fluorinated hydrocarbon group having 1 to 3 carbon atoms represented by R ²¹ to R ²⁶ is limited to a perfluorohydrocarbon group as long as it has at least one fluorine atom. It's not something you can do.
In compound (2), the fluorinated hydrocarbon group having 1 to 3 carbon atoms represented by R ²¹ to R ²⁶ may be a linear fluorinated hydrocarbon group, or may have a branched and/or ring structure. It may also be a fluorinated hydrocarbon group.
The fluorinated hydrocarbon group having 1 to 3 carbon atoms represented by R ²¹ to R ²⁶ is preferably a fluorinated alkyl group, a fluorinated alkenyl group, or a fluorinated alkynyl group; is more preferred, and a fluorinated alkyl group is particularly preferred.
The number of carbon atoms in the fluorinated hydrocarbon group having 1 to 3 carbon atoms represented by R ²¹ to R ²⁶ is preferably 1 or 2, and more preferably 1.

Specific examples of compound (2) include the following compounds (2-1) to (2-21), but compound (2) is not limited to these specific examples.
Among these, compound (2-1) is particularly preferred.

When the nonaqueous electrolyte contains a combination of compound (1) and compound (2) as additive S, the content of compound (2) is 0.001% by mass with respect to the total amount of the nonaqueous electrolyte. ~10% by mass is preferred, 0.001% by mass to 5% by mass is more preferred, even more preferably 0.001% to 3% by mass, and even more preferably 0.01% to 3% by mass. It is preferably 0.1 to 3% by weight, more preferably 0.1 to 2% by weight, and particularly preferably 0.1 to 1% by weight.

Further, when the non-aqueous electrolyte contains a combination of compound (1) and compound (2) as additive S, the content mass ratio of compound (2) to compound (1) (i.e. content mass ratio [compound (2)/Compound (1)]) is preferably from 0.1 to 10, more preferably from 0.2 to 5.0, even more preferably from 0.3 to 3.0.

-Compound (3)-

In compound (3), R ³¹ to R ³⁴ each independently represent a hydrogen atom, a fluorine atom, a hydrocarbon group having 1 to 3 carbon atoms, or a fluorinated hydrocarbon group having 1 to 3 carbon atoms.

A preferred embodiment of the hydrocarbon group having 1 to 3 carbon atoms represented by R ³¹ to R ³⁴ in compound (3) is the hydrocarbon group having 1 to 3 carbon atoms represented by R ²¹ to R ²⁶ in compound (2). This is the same as the preferred embodiment of the hydrocarbon group.

Specific examples of compound (3) include the following compounds (3-1) to (3-21), but compound (3) is not limited to these specific examples.
Among these, compound (3-1) is particularly preferred.

When the non-aqueous electrolyte contains a combination of compound (1) and compound (3) as additive S, the content of compound (3) is 0.001% by mass with respect to the total amount of the non-aqueous electrolyte. ~10% by mass is preferred, 0.001% by mass to 5% by mass is more preferred, even more preferably 0.001% to 3% by mass, and even more preferably 0.01% to 3% by mass. It is preferably 0.1 to 3% by weight, more preferably 0.1 to 2% by weight, and particularly preferably 0.1 to 1% by weight.

Further, when the non-aqueous electrolyte contains a combination of compound (1) and compound (3) as additive S, the content mass ratio of compound (3) to compound (1) (i.e. content mass ratio [compound (3)/Compound (1)]) is preferably from 0.1 to 10, more preferably from 0.2 to 5.0, even more preferably from 0.3 to 3.0.

-Compound (4)-

In compound (4), R ⁴¹ to R ⁴⁴ each independently represent a hydrogen atom, a hydrocarbon group having 1 to 6 carbon atoms, a group represented by formula (4a), or a group represented by formula (4b). represents. In formula (4a) and formula (4b), * represents the bonding position.

In compound (4), the hydrocarbon group having 1 to 6 carbon atoms represented by R ⁴¹ to R ⁴⁴ may be a straight chain hydrocarbon group or a hydrocarbon group having a branched and/or ring structure. It may be.
The hydrocarbon group having 1 to 6 carbon atoms represented by R ⁴¹ to R ⁴⁴ is preferably an alkyl group, an alkenyl group, or an alkynyl group, more preferably an alkyl group or an alkenyl group, and particularly preferably an alkyl group.
The number of carbon atoms in the hydrocarbon group having 1 to 6 carbon atoms represented by R ⁴¹ to R ⁴⁴ is preferably 1 to 3, more preferably 1 or 2, and particularly preferably 1.

Specific examples of compound (4) include the following compounds (4-1) to (4-7), but compound (4) is not limited to these specific examples.
Among these, compound (4-1) is particularly preferred.

When the nonaqueous electrolyte contains a combination of compound (1) and compound (4) as additive S, the content of compound (4) is 0.001% by mass with respect to the total amount of the nonaqueous electrolyte. ~10% by mass is preferred, 0.001% by mass to 5% by mass is more preferred, even more preferably 0.001% to 3% by mass, and even more preferably 0.01% to 3% by mass. It is preferably 0.1 to 3% by weight, more preferably 0.1 to 2% by weight, and particularly preferably 0.1 to 1% by weight.

In addition, when the non-aqueous electrolyte contains a combination of compound (1) and compound (4) as additive S, the content mass ratio of compound (4) to compound (1) (i.e. content mass ratio [compound (4)/Compound (1)]) is preferably from 0.1 to 10, more preferably from 0.2 to 5.0, even more preferably from 0.3 to 3.0.

-Average S-O bond number-
If the average number of oxygen atoms directly bonded to one sulfur atom in additive S is the average number of S-O bonds in additive S, then the average number of S-O bonds in additive S is 3. It is preferably .10 to 3.90.
When the average number of S--O bonds of the additive S is 3.10 to 3.90, the effect of the battery of the first aspect (the effect of suppressing the increase in battery resistance during storage) is more effectively achieved. .
The average number of SO bonds in the additive S is more preferably 3.20 to 3.80.

The average number of SO bonds in the additive S is determined as follows.
First, for each compound contained in the additive S, the average value of the number of oxygen atoms directly bonded to one sulfur atom (hereinafter referred to as "average number of SO bonds of the compound") is determined.
In a compound containing only one sulfur atom in one molecule, the average number of S—O bonds in the compound corresponds to the number of oxygen atoms directly bonded to one sulfur atom. For example, the above-mentioned compound (1-4) containing only one sulfur atom has an average number of S—O bonds of four.
For compounds containing two or more sulfur atoms in one molecule, the average number of S-O bonds in the compound is determined by calculating the number of oxygen atoms directly bonded to one sulfur atom for each sulfur atom. Obtain by simple averaging of the values. For example, the above-mentioned compound (1-2) containing one sulfur atom to which the number of directly bonded oxygen atoms is 4 and one sulfur atom to which the number of directly bonded oxygen atoms is 3 The average number of SO bonds in the compound is 3.5. Further, the above-mentioned compound (1-1) containing two sulfur atoms to which the number of directly bonded oxygen atoms is 4 has an average number of S—O bonds of 4.

The average number of SO bonds of the additive S is determined by weighted averaging the average number of SO bonds of each compound contained in the additive S based on the molar ratio of each compound based on sulfur atoms.
Specifically, in Equation 1 below, the average number of S--O bonds of compounds of type _i (i represents an integer of 1 or more) contained in additive S is substituted for S i, and W _i is By substituting the molar fraction of the i-type compound in S on a sulfur atom basis, the weighted average value of each compound contained in the additive S (i.e., the average S- The number of O bonds) can be calculated.

For example, for the additive S in Example 101, which will be described later, the average number of SO bonds in the additive S is determined as follows.
The non-aqueous electrolyte in Example 101 contained compound (1-1) whose content was 0.75% by mass based on the total amount of the non-aqueous electrolyte as the additive S, and compound (1-1) whose content was 0.75% by mass based on the total amount of the non-aqueous electrolyte. 0.25% by mass of compound (4-1).
Compound (1-1) has a molecular weight of 246, and compound (4-1) has a molecular weight of 108. Compound (1-1) contains two sulfur atoms in one molecule, and compound (4-1) contains one sulfur atom in one molecule.
From these facts, the molar ratio [compound (1-1): compound (4-1)] on the basis of sulfur atoms in additive S is determined to be 0.725:0.275 according to the following formula.
Molar ratio based on sulfur atoms in additive S [compound (1-1): compound (4-1)]
=((0.75/246)×2):(0.25/108)
=0.00610:0.00231
=0.725:0.275

Here, the compound (1-1) has an average number of SO bonds of 4, and the compound (4-1) has an average number of SO bonds of 3.
Therefore, the average number of SO bonds in the additive S is determined to be 3.72 using the following formula (see Table 2 below).
Average number of SO bonds in additive S = (4 x 0.725 + 3 x 0.275) / (0.725 + 0.275)
=3.72

Next, other components of the non-aqueous electrolyte will be explained. A non-aqueous electrolyte generally contains an electrolyte and a non-aqueous solvent.

(Non-aqueous solvent)
A non-aqueous electrolyte generally contains a non-aqueous solvent.
The number of non-aqueous solvents that may be contained in the non-aqueous electrolyte may be only one, or two or more.
As the non-aqueous solvent, various known ones can be appropriately selected.
As the nonaqueous solvent, for example, the nonaqueous solvents described in paragraphs 0069 to 0087 of JP 2017-45723A can be used.

Preferably, the nonaqueous solvent contains a cyclic carbonate compound and a chain carbonate compound.
In this case, the number of cyclic carbonate compounds and chain carbonate compounds contained in the nonaqueous solvent may be one, or two or more.

Examples of the cyclic carbonate compound include ethylene carbonate, propylene carbonate, 1,2-butylene carbonate, 2,3-butylene carbonate, 1,2-pentylene carbonate, and 2,3-pentylene carbonate.
Among these, ethylene carbonate and propylene carbonate, which have a high dielectric constant, are preferred. In the case of a battery using a negative electrode active material containing graphite, the nonaqueous solvent more preferably contains ethylene carbonate.

Examples of chain carbonate compounds include dimethyl carbonate, methylethyl carbonate, diethyl carbonate, methylpropyl carbonate, methylisopropyl carbonate, ethylpropyl carbonate, dipropyl carbonate, methylbutyl carbonate, ethylbutyl carbonate, dibutyl carbonate, methylpentyl carbonate, and ethylpentyl. carbonate, dipentyl carbonate, methylheptyl carbonate, ethylheptyl carbonate, diheptyl carbonate, methylhexyl carbonate, ethylhexyl carbonate, dihexyl carbonate, methyloctyl carbonate, ethyl octyl carbonate, dioctyl carbonate, and the like.

Examples of combinations of cyclic carbonate and linear carbonate include ethylene carbonate and dimethyl carbonate, ethylene carbonate and methyl ethyl carbonate, ethylene carbonate and diethyl carbonate, propylene carbonate and dimethyl carbonate, propylene carbonate and methyl ethyl carbonate, propylene carbonate and Diethyl carbonate, ethylene carbonate and propylene carbonate and methyl ethyl carbonate, ethylene carbonate and propylene carbonate and diethyl carbonate, ethylene carbonate and dimethyl carbonate and methyl ethyl carbonate, ethylene carbonate and dimethyl carbonate and diethyl carbonate, ethylene carbonate and methyl ethyl carbonate and diethyl carbonate , ethylene carbonate and dimethyl carbonate and methyl ethyl carbonate and diethyl carbonate, ethylene carbonate and propylene carbonate and dimethyl carbonate and methyl ethyl carbonate, ethylene carbonate and propylene carbonate and dimethyl carbonate and diethyl carbonate, ethylene carbonate and propylene carbonate and methyl ethyl carbonate and diethyl carbonate, ethylene carbonate, propylene carbonate, dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, and the like.

The mixing ratio of the cyclic carbonate compound and the chain carbonate compound, expressed in mass ratio, is cyclic carbonate compound:chain carbonate compound, for example, 5:95 to 80:20, preferably 10:90 to 70:30, more preferably is from 15:85 to 55:45. By setting such a ratio, it is possible to suppress the increase in viscosity of the non-aqueous electrolyte and increase the degree of dissociation of the electrolyte, thereby increasing the conductivity of the non-aqueous electrolyte, which is related to the charging and discharging characteristics of the battery. . Furthermore, the solubility of the electrolyte can be further increased. Therefore, a non-aqueous electrolyte having excellent electrical conductivity at room temperature or low temperature can be obtained, so that the load characteristics of the battery at room temperature or low temperature can be improved.

(Electrolytes)
A non-aqueous electrolyte generally contains an electrolyte.
As the electrolyte, various known electrolytes can be used, and any electrolyte that is normally used as an electrolyte for non-aqueous electrolytes can be used.

Specific examples of electrolytes include (C ₂ H ₅ ) ₄ NPF ₆ , (C ₂ H ₅ ) ₄ NBF ₄ , (C ₂ H ₅ ) ₄ NClO ₄ , (C ₂ H ₅ ) ₄ NAsF ₆ , (C ₂ H ₅ ) ₄ N ₂ SiF ₆ , (C ₂ H ₅ ) ₄ NOSO ₂ C _k F _(2k+1) (k=integer from 1 to 8), (C ₂ H ₅ ) ₄ NPF _n [C _k F _(2k+1) ] _(6-n) Tetraalkylammonium salts such as (n=1 to 5, k=an integer of 1 to 8), LiPF ₆ , LiBF ₄ , LiClO ₄ , LiAsF ₆ , Li ₂ SiF ₆ , LiOSO ₂ C _k F _(2k+1) (k=an integer of 1 to 8), LiPF _n [C _k F _(2k+1) ] _(6-n) (n=1 to 5, k=an integer of 1 to 8), and other lithium salts. . Furthermore, a lithium salt represented by the following general formula can also be used.

LiC( _SO2R7 )( ^SO2R8 )( ^{SO2R9 ) ,} LiN( _SO2OR10 ) ^{( SO2OR11} ₎ , _LiN ( _SO2R12 )( _SO2R13 ⁾ ( _where R ⁷ to R ¹³ may be the same or different and are a fluorine atom or a perfluoroalkyl group having 1 to 8 carbon atoms). These electrolytes may be used alone, or two or more types may be mixed.
Among these, lithium salts are particularly desirable, and furthermore, LiPF ₆ , LiBF ₄ , LiOSO ₂ C _k F _(2k+1) (k=an integer of 1 to 8), LiClO ₄ , LiAsF ₆ , LiNSO ₂ [C _k F _{( 2k+1)} ] ₂ (k=an integer of 1 to 8), LiPF _n [C _k F _(2k+1) ] _(6−n) (n=1 to 5, k=an integer of 1 to 8) are preferred.

The electrolyte is normally contained in the nonaqueous electrolyte at a concentration of 0.1 mol/L to 3 mol/L, preferably 0.5 mol/L to 2 mol/L.

Preferably, the electrolyte contains _LiPF6 .
Since LiPF ₆ has a high degree of dissociation, it can increase the conductivity of the electrolyte and further has the effect of suppressing the reductive decomposition reaction of the non-aqueous electrolyte on the negative electrode.
LiPF ₆ may be used alone, or LiPF ₆ and other electrolytes may be used. Any other electrolyte that is normally used as an electrolyte for non-aqueous electrolytes can be used, but among the specific examples of lithium salts mentioned above, lithium salts other than LiPF ₆ are preferred. .
Specific examples include LiPF ₆ and LiBF ₄ , LiPF ₆ and LiN [SO ₂ C _k F _(2k+1) ] ₂ (k=an integer from 1 to 8), LiPF ₆ and LiBF ₄ and LiN [SO ₂ C _k F _{( 2k+1)} ] (k=an integer from 1 to 8).

The proportion of LiPF ₆ in the lithium salt is preferably 1% by mass to 100% by mass, more preferably 10% by mass to 100% by mass, even more preferably 50% by mass to 100% by mass. Such an electrolyte is preferably contained in the non-aqueous electrolyte at a concentration of 0.1 mol/L to 3 mol/L, preferably 0.5 mol/L to 2 mol/L.

<Negative electrode>
The negative electrode may include a negative electrode active material and a negative electrode current collector.
The negative electrode active materials in the negative electrode include metallic lithium, lithium-containing alloys, metals or alloys that can be alloyed with lithium, oxides that can dope and dedope lithium ions, and oxides that can dope and dedope lithium ions. At least one member selected from the group consisting of a transition metal nitride and a carbon material capable of doping and dedoping lithium ions (it may be used alone or a mixture containing two or more of these may be used) good) can be used.
Examples of metals or alloys that can be alloyed with lithium (or lithium ions) include silicon, silicon alloys, tin, and tin alloys. Alternatively, lithium titanate may be used.
Among these, carbon materials that can be doped and dedoped with lithium ions are preferred. Examples of such carbon materials include carbon black, activated carbon, graphite (artificial graphite, natural graphite), amorphous carbon materials, and the like. The carbon material may be in any of fibrous, spherical, potato-like, and flake-like forms.

Specific examples of the amorphous carbon material include hard carbon, coke, mesocarbon microbeads (MCMB) fired at 1500° C. or lower, and mesophase pitch carbon fiber (MCF).
Examples of the graphite include natural graphite and artificial graphite. As the artificial graphite, graphitized MCMB, graphitized MCF, etc. are used. Further, as the graphite, one containing boron can also be used. Further, as the graphite, those coated with metals such as gold, platinum, silver, copper, and tin, those coated with amorphous carbon, and those coated with a mixture of amorphous carbon and graphite can also be used.

These carbon materials may be used alone or in combination of two or more.
The above-mentioned carbon material is particularly preferably a carbon material in which the interplanar spacing d(002) of the (002) plane measured by X-ray analysis is 0.340 nm or less. Further, as the carbon material, graphite having a true density of 1.70 g/cm ³ or more or a highly crystalline carbon material having properties similar to graphite is also preferable. By using carbon materials such as those described above, it is possible to further increase the energy density of the battery.

It is particularly preferable that the negative electrode active material contains graphite.
As a result, a film caused by the additive S is more likely to be formed on the surface of the negative electrode, and the area ratio [peak 1/peak 2] of 10 to 150 is more likely to be satisfied.

The material of the negative electrode current collector in the negative electrode is not particularly limited, and any known material can be used.
Specific examples of the negative electrode current collector include metal materials such as copper, nickel, stainless steel, and nickel-plated steel. Among these, copper is particularly preferred from the viewpoint of ease of processing.

<Positive electrode>
The positive electrode may include a positive electrode active material and a positive electrode current collector.
As the positive electrode active material in the positive electrode, transition metal oxides or transition metal sulfides such as MoS ₂ , TiS ₂ , MnO ₂ , V ₂ O ₅ , LiCoO ₂ , LiMnO ₂ , LiMn ₂ O ₄ , LiNiO ₂ , LiNi _X Co _{( 1 -X) O 2} [0 _< ≦(1+α)/(1-α)≦1.6), LiNi _x Co _y Mn _z O ₂ [x+y+z=1, 0<x<1, 0<y<1, 0<z<1] (for example, Composite oxides made of lithium and transition metals such as LiNi _0.33 Co _0.33 Mn _0.33 O ₂ , LiNi _0.5 Co _0.2 Mn _0.3 O ₂ etc.), LiFePO ₄ and LiMnPO ₄ ; Examples include conductive polymer materials such as polyaniline, polythiophene, polypyrrole, polyacetylene, polyacene, dimercaptothiadiazole, and polyaniline composites. Among these, a composite oxide consisting of lithium and a transition metal is particularly preferred. When the negative electrode is lithium metal or lithium alloy, a carbon material can also be used as the positive electrode. Moreover, a mixture of a composite oxide of lithium and a transition metal and a carbon material can also be used as the positive electrode.
One type of positive electrode active material may be used, or two or more types may be used in combination. If the positive electrode active material has insufficient electrical conductivity, it can be used together with a conductive additive to form a positive electrode. Examples of the conductive aid include carbon materials such as carbon black, amorphous whiskers, and graphite.

The material of the positive electrode current collector in the positive electrode is not particularly limited, and any known material can be used.
Specific examples of the positive electrode current collector include metal materials such as aluminum, aluminum alloy, stainless steel, nickel, titanium, and tantalum; carbon materials such as carbon cloth and carbon paper; and the like.

<Separator>
The battery according to the first aspect of the present disclosure preferably includes a separator between the negative electrode and the positive electrode.
The separator is a membrane that electrically insulates the positive electrode and the negative electrode and transmits lithium ions, and examples thereof include a porous membrane and a polymer electrolyte.
A microporous polymer film is preferably used as the porous membrane, and examples of the material include polyolefin, polyimide, polyvinylidene fluoride, and polyester.
Particularly preferred are porous polyolefins, and specific examples include porous polyethylene films, porous polypropylene films, and multilayer films of porous polyethylene films and polypropylene films. Other resins having excellent thermal stability may be coated on the porous polyolefin film.
Examples of the polymer electrolyte include a polymer in which a lithium salt is dissolved, a polymer swollen with an electrolytic solution, and the like.
The above-mentioned non-aqueous electrolyte may be used for the purpose of swelling a polymer to obtain a polymer electrolyte.

<Battery configuration>
The battery according to the first aspect is not particularly limited as long as it has the above-described configuration, but is particularly preferably a lithium secondary battery.
When the battery according to the first aspect is a lithium secondary battery, the lithium secondary battery can take various known shapes, such as a cylindrical shape, a coin shape, a square shape, a laminate shape, a film shape, and other arbitrary shapes. can be formed. However, the basic structure of a battery is the same regardless of its shape, and the design can be changed depending on the purpose.

An example of a lithium secondary battery is a laminate type battery.
FIG. 1 is a schematic perspective view showing an example of a laminated battery, which is an example of a lithium secondary battery, and FIG. 2 is a schematic perspective view of a laminated electrode body housed in the laminated battery shown in FIG. 1 in the thickness direction. FIG.
The laminated battery shown in FIG. 1 contains a non-aqueous electrolyte (not shown in FIG. 1) and a laminated electrode body (not shown in FIG. 1), and has a sealed peripheral edge. The device includes a laminate exterior body 1 whose interior is hermetically sealed. As the laminate exterior body 1, for example, a laminate exterior body made of aluminum is used.
As shown in FIG. 2, the laminated electrode body housed in the laminate exterior body 1 includes a laminated body in which positive electrode plates 5 and negative electrode plates 6 are alternately laminated with separators 7 in between, and a laminated body of this laminated body. A separator 8 surrounding the periphery is provided. The positive electrode plate 5, the negative electrode plate 6, the separator 7, and the separator 8 are impregnated with the above-mentioned non-aqueous electrolyte.
Each of the plurality of positive electrode plates 5 in the laminated electrode body is electrically connected to the positive electrode terminal 2 via a positive electrode tab (not shown), and a part of the positive electrode terminal 2 is connected to the laminate exterior body 1. It protrudes outward from the peripheral edge (Figure 1). A portion of the peripheral end of the laminate exterior body 1 from which the positive electrode terminal 2 protrudes is sealed with an insulating seal 4.
Similarly, each of the plurality of negative electrode plates 6 in the laminated electrode body is electrically connected to the negative electrode terminal 3 via a negative electrode tab (not shown), and a part of the negative electrode terminal 3 is connected to the laminate exterior. It protrudes outward from the peripheral end of the body 1 (Fig. 1). A portion of the peripheral end of the laminate exterior body 1 from which the negative electrode terminal 3 protrudes is sealed with an insulating seal 4.
In addition, in the laminated battery according to the above example, the number of positive electrode plates 5 is five and the number of negative electrode plates 6 is six, and the positive electrode plates 5 and the negative electrode plates 6 are connected to the uppermost part of both sides with a separator 7 in between. The outer layers are laminated in such a manner that each of them becomes a negative electrode plate 6. However, it goes without saying that the number of positive electrode plates, the number of negative electrode plates, and their arrangement in the laminate type battery are not limited to this example, and various changes may be made.

Another example of a lithium secondary battery is a coin-type battery.
FIG. 3 is a schematic perspective view showing an example of a coin-type battery, which is another example of a lithium secondary battery.
In the coin-type battery shown in FIG. 3, a disc-shaped negative electrode 12, a separator 15 injected with a non-aqueous electrolyte, a disc-shaped positive electrode 11, and spacer plates 17 and 18 made of stainless steel or aluminum, if necessary, are arranged in this order. The stacked state is stored between the positive electrode can 13 (hereinafter also referred to as "battery can") and the sealing plate 14 (hereinafter also referred to as "battery can lid"). The positive electrode can 13 and the sealing plate 14 are caulked and sealed via a gasket 16.
In this example, the above-mentioned non-aqueous electrolyte is used as the non-aqueous electrolyte injected into the separator 15.

Note that a lithium secondary battery is a lithium secondary battery obtained by charging and discharging a lithium secondary battery (a lithium secondary battery before charging and discharging) that includes a negative electrode, a positive electrode, and the above-mentioned nonaqueous electrolyte. It may also be a battery.
That is, a lithium secondary battery is manufactured by first producing a lithium secondary battery containing a negative electrode, a positive electrode, and the above-mentioned non-aqueous electrolyte before charging and discharging, and then manufacturing the lithium secondary battery before charging and discharging. It may be a lithium secondary battery produced by charging and discharging one or more times (charged and discharged lithium secondary battery).

The use of the battery (preferably a lithium secondary battery) according to the first aspect is not particularly limited, and can be used for various known uses. For example, notebook computers, mobile computers, mobile phones, headphone stereos, video movies, LCD TVs, handy cleaners, electronic notebooks, calculators, radios, backup power supplies, motors, automobiles, electric vehicles, motorcycles, electric motorcycles, bicycles, electric It can be widely used in bicycles, lighting equipment, game consoles, watches, power tools, cameras, etc., regardless of whether they are small portable devices or large devices.

[Second aspect; non-aqueous electrolyte for batteries]
The non-aqueous electrolyte for batteries according to the second aspect of the present disclosure includes:
The following compound (1) and
At least one of the following compound (2), the following compound (3), and the following compound (4),
Contains.

In compound (1), R ¹¹ to R ¹⁴ each independently represent a hydrogen atom, a hydrocarbon group having 1 to 6 carbon atoms, a group represented by formula (1a), or a group represented by formula (1b). represents. In formula (1a) and formula (1b), * represents the bonding position.
In compound (2), R ²¹ to R ²⁶ each independently represent a hydrogen atom, a fluorine atom, a hydrocarbon group having 1 to 3 carbon atoms, or a fluorinated hydrocarbon group having 1 to 3 carbon atoms.
In compound (3), R ³¹ to R ³⁴ each independently represent a hydrogen atom, a fluorine atom, a hydrocarbon group having 1 to 3 carbon atoms, or a fluorinated hydrocarbon group having 1 to 3 carbon atoms.
In compound (4), R ⁴¹ to R ⁴⁴ each independently represent a hydrogen atom, a hydrocarbon group having 1 to 6 carbon atoms, a group represented by formula (4a), or a group represented by formula (4b). represents. In formula (4a) and formula (4b), * represents the bonding position.

According to the nonaqueous electrolyte for a battery according to the second aspect, an increase in battery resistance during storage is suppressed.
The effect of suppressing the increase in battery resistance during storage is particularly remarkable with respect to battery resistance under low temperature conditions (for example, -20°C).
Although the reason for this effect is not clear, in a battery using the non-aqueous battery electrolyte according to the second aspect, compound (1), compound (2), compound (3), and at least one of compound (4), and this film has a property that the increase in resistance is small or the resistance is further reduced during storage of the battery. it is conceivable that.

The nonaqueous electrolyte for a battery according to the second aspect is suitable as the nonaqueous electrolyte in the battery according to the first aspect described above.
However, the non-aqueous electrolyte for batteries according to the second aspect is not limited to being used in batteries having an area ratio [peak 1/peak 2] of 10 to 150.

A preferred embodiment of the non-aqueous electrolyte for a battery according to the second aspect is that it is not limited to being used in a battery having an area ratio [peak 1/peak 2] of 10 to 150. This is the same as the preferred embodiment of the non-aqueous electrolyte in .

Examples of the present disclosure will be shown below, but the present disclosure is not limited to the following examples.
In the following, "addition amount" means the content based on the total amount of the non-aqueous electrolyte finally obtained, and "wt%" means mass %.

[Example 1]
A coin-type battery (test battery), which is a lithium secondary battery, was produced using the following procedure.
<Preparation of negative electrode>
A paste-like negative electrode mixture slurry was prepared by kneading amorphous coated natural graphite (97 parts by mass), carboxymethyl cellulose (1 part by mass), and SBR latex (2 parts by mass) with a water solvent.
Next, this negative electrode mixture slurry is applied to a 10 μm thick strip-shaped copper foil negative electrode current collector, dried, and then compressed with a roll press to form a sheet-like negative electrode consisting of the negative electrode current collector and negative electrode active material layer. I got it. The coating density of the negative electrode active material layer at this time was 10 mg/cm ² and the packing density was 1.5 g/ml.

<Preparation of positive electrode>
LiNi _0.5 Mn _0.3 Co _0.2 O ₂ (90 parts by mass), acetylene black (5 parts by mass) and polyvinylidene fluoride (5 parts by mass) were kneaded using N-methylpyrrolidinone as a solvent to form a paste. A positive electrode mixture slurry was prepared.
Next, this positive electrode mixture slurry is applied to a positive electrode current collector made of a strip of aluminum foil with a thickness of 20 μm, dried, and then compressed with a roll press to form a sheet-like positive electrode consisting of a positive electrode current collector and a positive electrode active material layer. I got it. The coating density of the positive electrode active material layer at this time was 30 mg/cm ² and the packing density was 2.5 g/ml.

<Preparation of non-aqueous electrolyte>
As a nonaqueous solvent, ethylene carbonate (EC), dimethyl carbonate (DMC), and methyl ethyl carbonate (EMC) were mixed at a ratio of 30:40:30 (mass ratio), respectively, to obtain a mixed solvent.
LiPF ₆ as an electrolyte was dissolved in the obtained mixed solvent so that the concentration of LiPF ₆ in the finally obtained non-aqueous electrolyte was 1.1 mol/L.
To the solution obtained above, the following compound (1-1) (addition amount 0.75% by mass) and the following compound (2-1) (addition amount 0.25% by mass) were added as additive S. A non-aqueous electrolyte was obtained.

(Calculation of average S-O bond number of additive S)
The average number of SO bonds of Additive S was calculated by the method described above.
The results are shown in Table 1.

<Production of coin-type battery>
The above-mentioned negative electrode was punched out into a disk shape with a diameter of 14 mm, and the above-mentioned positive electrode was punched out into a disk shape with a diameter of 13 mm to obtain a coin-shaped negative electrode and a coin-shaped positive electrode, respectively. Further, a 20 μm thick microporous polyethylene film was punched out into a disc shape with a diameter of 17 mm to obtain a separator.
The obtained coin-shaped negative electrode, separator, and coin-shaped positive electrode were stacked in this order in a stainless steel battery can (2032 size), and then 20 μL of the above-mentioned non-aqueous electrolyte was poured into the battery can. It was injected into the separator, positive electrode, and negative electrode.
Next, an aluminum plate (thickness: 1.2 mm, diameter: 16 mm) and a spring were placed on the positive electrode, and a battery can lid was caulked through a polypropylene gasket to seal the battery.
As a result, a coin-shaped battery (ie, a coin-shaped lithium secondary battery) having the configuration shown in FIG. 3 and having a diameter of 20 mm and a height of 3.2 mm was obtained.

<XPS of negative electrode surface>
The obtained coin-type battery was subjected to conditioning.
Here, "conditioning" refers to charging and discharging a coin-type battery three times between 2.75V and 4.2V in a constant temperature bath at 25°C (the same shall apply hereinafter). .
After conditioning, the coin-shaped battery was disassembled and the coin-shaped negative electrode was taken out.
A narrow spectrum of sulfur atoms was measured by X-ray photoelectron spectroscopy (XPS, ESCA) on the surface of the taken out negative electrode that was facing the separator, and peak separation was performed on the S2p orbit.
Based on the obtained results, the area ratio (area ratio [peak 1/peak 2]) was calculated.
The results are shown in Table 1.

The detailed conditions for X-ray photoelectron spectroscopy (XPS, ESCA) are as follows.
・Device: AXIS-NOVA (manufactured by KratoS)
・X-ray source: Monochromatic AlKα (1486.6eV)
・Analysis area: 700μm x 300μm

<Evaluation of battery resistance>
The obtained coin-shaped battery was subjected to conditioning, and the battery resistance of the coin-shaped battery after conditioning was evaluated.
Hereinafter, "high-temperature storage" refers to an operation in which a coin-type battery is stored at 60° C. for 72 hours in a constant temperature bath.
Hereinafter, battery resistance (DCIR) was measured under two temperature conditions, 25°C and -20°C.

(Measurement of battery resistance (DCIR) before high temperature storage)
The SOC (State of Charge) of the coin-shaped battery after conditioning was adjusted to 80%, and then, the DCIR (Direct current internal resistance) of the coin-shaped battery before high temperature storage was measured by the following method.
Using the above coin-type battery adjusted to SOC 80%, CC10s discharge at a discharge rate of 0.2C, pause for 300 seconds, CC10s discharge at a discharge rate of 1C, pause for 300 seconds, CC10s discharge at a discharge rate of 2C, A pause of 300 seconds and CC10s discharge at a discharge rate of 5C were performed in this order.
Note that CC10s discharge means discharging at a constant current for 10 seconds.
The DC resistance is calculated based on the relationship between each discharge rate and the voltage 10 seconds after the start of discharge at each discharge rate, and the obtained DC resistance (Ω) is calculated as the battery resistance of the coin-type battery before high temperature storage ( Ω).
The results are shown in Table 1.

(Measurement of battery resistance (DCIR) after high temperature storage)
After conditioning, but before adjusting the SOC to 80%, the coin-type battery is CC-CV charged to 4.25V at a charging rate of 0.2C at 25℃ in a thermostatic chamber, and then stored at high temperature. The battery resistance (Ω) after high-temperature storage was measured in the same manner as the measurement of battery resistance before high-temperature storage described above, except that .
The results are shown in Table 1.
Here, CC-CV charging means constant current-constant voltage.

(Measurement of rate of increase in battery resistance during high temperature storage)
The rate of increase in battery resistance during high-temperature storage (in Table 1, simply referred to as "rate of increase (%)") was calculated using the following formula. The results are shown in Table 1.
Rate of increase in battery resistance (%) during high temperature storage
= [(Battery resistance after high temperature storage (Ω) - Battery resistance before high temperature storage (Ω)) / Battery resistance before high temperature storage (Ω)] × 100

The rate of increase (%) may not only be a positive value but also a negative value or 0.
A positive value for the rate of increase (%) means that the battery resistance has increased during high-temperature storage, and a negative value for the rate of increase (%) means that the battery resistance has increased during high-temperature storage. The increase rate (%) of 0 means that the battery resistance did not change during high-temperature storage.

[Example 2 and 3]
In preparing the nonaqueous electrolyte, the same operation as in Example 1 was performed except that the amount of compound (1-1) and the amount of compound (2-1) added were changed as shown in Table 1. .
The results are shown in Table 1.

[Comparative example 1]
In preparing the non-aqueous electrolyte, the same operation as in Example 1 was performed except that compound (2-1) was not used and the amount of compound (1-1) added was changed as shown in Table 1. Ta.
The results are shown in Table 1.

[Comparative example 2]
In preparing the non-aqueous electrolyte, the same operation as in Example 1 was performed except that compound (1-1) was not used and the amount of compound (2-1) added was changed as shown in Table 1. Ta.
The results are shown in Table 1.

As shown in Table 1, it was confirmed that in Examples 1 to 3 in which the area ratio [Peak 1/Peak 2] was 10 to 150, the increase in battery resistance during high temperature storage was suppressed.
The effect of suppressing the increase in battery resistance was particularly remarkable in battery resistance under low temperature (-20°C) conditions.

[Examples 101 to 103, and Comparative Example 101 and Comparative Example 102]
The same operations as in Examples 1 to 3 and Comparative Examples 1 and 2 were performed except that compound (2-1) was replaced with the same mass of compound (4-1) below.
Note that Comparative Example 101 is the same as Comparative Example 1 described above.
The results are shown in Table 2.

As shown in Table 2, in Examples 101 to 103 in which the area ratio [Peak 1/Peak 2] was 10 to 150, it was confirmed that the increase in battery resistance during high temperature storage was suppressed.
The effect of suppressing the increase in battery resistance was particularly remarkable in battery resistance under low temperature (-20°C) conditions.

1 Laminate exterior body 2 Positive electrode terminal 3 Negative electrode terminal 4 Insulating seal 5 Positive electrode plate 6 Negative electrode plates 7, 8 Separator 11 Positive electrode 12 Negative electrode 13 Positive electrode can 14 Sealing plate 15 Separator 16 Gasket 17, 18 Spacer plate

Claims (5)

A battery comprising a positive electrode, a negative electrode, and a non-aqueous electrolyte,
The non-aqueous electrolyte contains an additive S containing a sulfur atom and an oxygen atom,
When measuring the narrow spectrum of sulfur atoms on the surface of the negative electrode by X-ray photoelectron spectroscopy and performing peak separation on the S2p orbit, 168. The area ratio of peak 1 observed in the region of 4 eV to 171.1 eV is 10 to 150,
The additive S is a battery comprising the following compound (1) and the following compound (2).

[In compound (1), R ¹¹ to R ¹⁴ are each independently a hydrogen atom, a hydrocarbon group having 1 to 6 carbon atoms, a group represented by formula (1a), or a group represented by formula (1b) represents a group (except when all of R ¹¹ to R ¹⁴ are hydrogen atoms). In formula (1a) and formula (1b), * represents the bonding position.
In compound (2), R ²¹ to R ²⁶ each independently represent a hydrogen atom, a fluorine atom, a hydrocarbon group having 1 to 3 carbon atoms, or a fluorinated hydrocarbon group having 1 to 3 carbon atoms. ] If the average number of oxygen atoms directly bonded to one sulfur atom in the additive S is the average number of S-O bonds in the additive S, then the average number of S-O bonds in the additive S is , 3.10 to 3.90. The negative electrode includes a negative electrode active material,
The battery according to claim 1 or 2, wherein the negative electrode active material contains graphite. The battery according to any one of claims 1 to 3, which is a lithium secondary battery. A non-aqueous electrolyte for batteries containing the following compound (1) and the following compound (2).

[In compound (1), R ¹¹ to R ¹⁴ are each independently a hydrogen atom, a hydrocarbon group having 1 to 6 carbon atoms, a group represented by formula (1a), or a group represented by formula (1b) represents a group (except when all of R ¹¹ to R ¹⁴ are hydrogen atoms). In formula (1a) and formula (1b), * represents the bonding position.
In compound (2), R ²¹ to R ²⁶ each independently represent a hydrogen atom, a fluorine atom, a hydrocarbon group having 1 to 3 carbon atoms, or a fluorinated hydrocarbon group having 1 to 3 carbon atoms. ]