JP7399626B2 - Non-aqueous electrolyte and energy devices using it - Google Patents

Description

The present invention relates to a nonaqueous electrolyte and an energy device using the same.

With the rapid advancement of portable electronic devices such as mobile phones and notebook personal computers, there is an increasing demand for higher capacity batteries used as main power sources and backup power sources. Energy devices such as lithium ion secondary batteries, which have higher energy density than hydrogen batteries, are attracting attention.
Examples of electrolytes for lithium ion secondary batteries include LiPF ₆ , LiBF ₄ , LiN(CF ₃
An electrolyte such as SO ₂ ) ₂ , LiCF ₃ (CF ₂ ) ₃ SO ₃ is mixed with a high dielectric constant solvent such as ethylene carbonate or propylene carbonate, and a low viscosity solvent such as dimethyl carbonate, diethyl carbonate, or ethyl methyl carbonate. A typical example is a non-aqueous electrolyte solution dissolved in .

In addition, carbonaceous materials that can absorb and release lithium ions are mainly used as negative electrode active materials for lithium ion secondary batteries, and typical examples include natural graphite, artificial graphite, and amorphous carbon. Can be mentioned. Furthermore, metal or alloy-based negative electrodes using silicon, tin, or the like are also known with the aim of increasing capacity. As the positive electrode active material, transition metal composite oxides capable of intercalating and deintercalating lithium ions are mainly used, and representative examples of the transition metals include cobalt, nickel, manganese, iron, and the like.

Since these lithium-ion secondary batteries use highly active positive and negative electrodes, it is known that side reactions between the electrodes and the electrolyte can cause a decrease in charge/discharge capacity, so it is important to improve battery characteristics. In order to achieve this, various studies have been made on non-aqueous organic solvents and electrolytes.
Patent Document 1 proposes a technique for improving high-temperature storage characteristics of a battery by using an electrolytic solution containing an alkyl nitrile.

Patent Document 2 describes a technology that improves battery charging and discharging efficiency by suppressing the decomposition reaction of the electrolyte on the negative electrode by using an electrolyte containing a nitrile compound having a carbon-carbon unsaturated bond. is proposed.
Patent Documents 3 and 4 propose a technique for suppressing swelling during battery storage at high temperatures by using an electrolytic solution containing a nitrile compound having a carbon-carbon unsaturated bond.

Patent Document 5 proposes a technique for suppressing the reductive decomposition reaction of a solvent that occurs when highly crystalline carbon such as graphite is used as a negative electrode by using an electrolytic solution containing a compound having a cyanoethoxy group. There is.
Patent Documents 6 and 7 propose techniques for suppressing battery swelling and capacity deterioration during high-temperature storage by using an electrolytic solution containing a nitrile compound having a specific unsaturated hydrocarbon group.

Patent Document 8 proposes a technique for suppressing capacity deterioration during high-temperature storage and cycle testing by using an electrolytic solution containing an aliphatic cyano compound having three or more cyano groups.

Japanese Patent Application Publication No. 10-189008 JP2003-86248A China Patent Application Publication No. 102738511 US Patent Application Publication No. 2014/0356734 Japanese Patent Application Publication No. 2000-243444 China Patent Application Publication No. 105428717 China Patent Application Publication No. 105742707 Japanese Patent Application Publication No. 2010-073367

The nitrile compounds described in Patent Documents 1 to 8 have a problem in that reduction side reactions also proceed on the negative electrode and the effect of improving battery characteristics is insufficient. In addition, the effect of their action on the positive electrode is weak, and there is a problem that the effect of improving durability characteristics in a battery high-temperature storage durability test is insufficient.
The present invention was made to solve the above problems, and provides a non-aqueous electrolytic solution that can simultaneously improve the initial capacity and rate characteristics after a high-temperature storage durability test in an energy device, and the non-aqueous electrolytic solution. The goal is to provide an energy device using

As a result of various studies to achieve the above object, the present inventors have discovered that the above problem can be solved by incorporating a carboxylic acid ester and a specific nitrile into the electrolyte in a specific ratio, The present invention has now been completed. The gist of the embodiments of the present invention is as shown below.
(a) A non-aqueous electrolytic solution for an energy device comprising a positive electrode and a negative electrode, the non-aqueous electrolytic solution together with an electrolyte and a non-aqueous solvent,
(A) carboxylic acid ester; and (B) at least one compound selected from the group consisting of compounds represented by formula (1) and formula (2).
The above (A) contains a species compound and is based on the total content of the above (A) group and the above (B) group.
) A non-aqueous electrolytic solution having a content of 50% by mass or more and 99.5% by mass or less.

(In the formula, R ¹ is an unsaturated hydrocarbon group having 3 to 12 carbon atoms that may have a substituent having at least one carbon-carbon unsaturated bond, and R ² is an unsaturated hydrocarbon group having 2 to 10 carbon atoms. ^R3 is an aliphatic hydrocarbon group having 1 to 10 carbon atoms, and a is 0 or 1.
It is. However, a plurality of R ³ 's may be the same or different. )

(b) The nonaqueous electrolyte according to (a), wherein the unsaturated hydrocarbon group of R ¹ in the formula (1) has at least one carbon-carbon double bond.
(c) In the formula (1), the unsaturated hydrocarbon group of R ¹ is an aliphatic unsaturated hydrocarbon group having at least one carbon-carbon double bond, as described in (a) or (b). non-aqueous electrolyte.
(d) In the formula (1), R ² is an alkylene group having 2 or more and 10 or less carbon atoms, (a) to (
The non-aqueous electrolyte according to any one of c).

(e) The non-aqueous electrolyte according to (a), wherein in formula (2), R ³ is an alkylene group having 2 or more and 10 or less carbon atoms.
(f) The non-aqueous electrolytic solution according to (a) or (e), wherein a is 0 in the formula (2).
(g) The non-aqueous electrolyte is a compound represented by the above formula (1) and/or the above formula (2)
(a) to (f) containing a compound represented by 0.001% by mass or more and 10% by mass or less
The non-aqueous electrolyte according to any one of the above.

(h) The non-aqueous electrolytic solution according to any one of (a) to (g), wherein the content of the carboxylic acid ester based on the total amount of the non-aqueous electrolytic solution is 0.001% by mass or more and 70% by mass or less.
(i) The non-aqueous electrolytic solution according to any one of (a) to (h), wherein the carboxylic acid ester is a propionic acid ester.
(j) Furthermore, a cyclic carbonate having a carbon-carbon unsaturated bond, a fluorine-containing cyclic carbonate, a sulfur-containing organic compound, a phosphorus-containing organic compound, an organic compound having a cyano group other than the above formulas (1) and (2), and isocyanate. (a ) to (i).

(k) cyclic carbonate having a carbon-carbon unsaturated bond, fluorine-containing cyclic carbonate,
Sulfur-containing organic compounds, phosphorus-containing organic compounds, organic compounds having a cyano group other than the above formulas (1) and (2), organic compounds having an isocyanate group, silicon-containing compounds, monofluorophosphates, difluorophosphates, (j ) The non-aqueous electrolyte described in ).
(l) An energy device comprising a negative electrode, a positive electrode, and the nonaqueous electrolyte according to any one of (a) to (k).

(m) The negative electrode has a negative electrode active material layer on a current collector, and the negative electrode active material layer includes a simple metal, alloy, and compound of silicon, a simple metal, alloy, and compound of tin, a carbonaceous material, and The energy device according to (l), containing at least one selected from the group consisting of lithium titanium composite oxides.
(n) The positive electrode has a positive electrode active material layer on the current collector, and the positive electrode active material layer is made of a lithium-cobalt composite oxide, a lithium-cobalt-nickel composite oxide,
Lithium-manganese composite oxide, lithium-cobalt-manganese composite oxide, lithium
Nickel composite oxide, lithium-nickel-manganese composite oxide,
and lithium-cobalt-nickel-manganese composite oxide, the energy device according to (l) or (m).

According to the present invention, it is possible to provide a non-aqueous electrolytic solution for realizing an energy device that simultaneously improves initial capacity and rate characteristics after a high-temperature storage durability test. This makes it possible to achieve smaller size, higher performance, and higher safety of energy devices.
In the energy device produced using the nonaqueous electrolyte of the present invention, the operation and principle by which the initial capacity and the rate characteristics after the high-temperature storage durability test are improved is not clear, but it is thought to be as follows. However, the present invention is not limited to the operation and principle described below.

Normally, nitrile compounds, as typified by Patent Document 1, suppress oxidative decomposition of non-aqueous electrolytes by coordinating cyano groups with metal oxides in the positive electrode active material, and suppress the oxidative decomposition of non-aqueous electrolyte solutions, resulting in gas emissions after high-temperature storage durability tests. It brings about improvement effects such as reducing occurrence. However, these nitrile compounds have low bonding energy to metal oxides and easily break off during durability tests, so their effectiveness in suppressing the oxidation reaction of non-aqueous electrolytes was small. Furthermore, since compounds having a cyano group have low resistance to reduction, reduction side reactions proceed significantly on the negative electrode. As a result, the charging/discharging efficiency after the durability test decreases, leading to capacity loss of the energy device.

In addition, compounds having a carbon-carbon unsaturated bond at the α-position relative to the cyano group, as represented by Patent Document 2, improve battery characteristics by coordinating the cyano group with the metal oxide in the positive electrode active material. bring about. However, because the carbon-carbon unsaturated bond and the electron-withdrawing cyano group are close to each other in the molecule, resistance to reduction at the negative electrode is low, and reduction side reactions on the negative electrode proceed significantly. Put it away. As a result, the charging/discharging efficiency after the durability test decreases, leading to capacity loss of the energy device.

Furthermore, in nitrile compounds having carbon-carbon unsaturated bonds, as typified by Patent Documents 3 and 4, the cyano group acts on the metal oxide in the positive electrode active material, resulting in the production of gas by-products, similar to the alkyl nitriles mentioned above. suppresses this and improves battery characteristics. In addition, the reaction of carbon-carbon unsaturated bonds forms a negative electrode protective film and improves battery characteristics. However, because the reduction reactivity of the carbon-carbon unsaturated bond is high due to the electron-withdrawing effect of the nitrile group, reduction side reactions on the negative electrode cannot be suppressed, and as a result, the charging after the durability test Discharge efficiency decreases, leading to capacity loss in energy devices.

In addition, the nitrile compounds having an ether group shown in Patent Documents 5 to 8 undergo a remarkable reductive decomposition reaction on the negative electrode, and a high-resistance film is formed on the positive electrode by oxidation of ether oxygen. The rate characteristics after the durability test deteriorate.
In the non-aqueous electrolyte of the present invention, in the compound represented by formula (1) and the compound represented by formula (2), ether oxygen and cyano group exist via an aliphatic hydrocarbon group. Therefore, the ether oxygen and the cyano group can be used to perform chelate coordination to the metal oxide of the positive electrode, increasing the bonding energy with the metal oxide. As a result, it can act stably on the metal oxide of the positive electrode. On the other hand, carboxylic acid esters produce anionic compounds as by-products by being reduced on the negative electrode, and when this substance is oxidized on the positive electrode, the positive electrode deteriorates. However, the expression (
Since the compound represented by 1) and the compound represented by formula (2) each have an unsaturated hydrocarbon group or multiple cyanoethoxy groups, they are capable of trapping oxidation reaction intermediates of anionic compounds. can. As a result, deterioration of the positive electrode caused by anionic compounds can be suppressed. On the other hand, the compound represented by formula (1) and the compound represented by formula (2) are
The ether oxygen moiety acts strongly on the metal cation in the system and approaches the outermost surface of the negative electrode, easily causing a reduction side reaction due to the CN group. However, the reaction between the side reaction intermediate produced here and the carboxylic acid ester suppresses the subsequent negative electrode deterioration side reaction. Furthermore, since the reaction product incorporates ether oxygen, it forms a high-quality insulating film with excellent metal cation conductivity. Therefore, the initial capacity and the rate characteristics after the high temperature storage durability test can be improved at the same time.

Embodiments of the present invention will be described below, but the present invention is not limited to these embodiments.
Any modifications can be made without departing from the spirit of the invention.

1. Non-Aqueous Electrolyte The non-aqueous electrolyte of the present invention is a non-aqueous electrolyte for an energy device having a positive electrode and a negative electrode, and the non-aqueous electrolyte contains a carboxylic acid ester of formula (1) together with an electrolyte and a non-aqueous solvent.
) or at least one compound selected from the group consisting of compounds represented by formula (2).
1-1. At least one compound selected from the group consisting of a carboxylic acid ester and a compound represented by formula (1) or formula (2)

1-1-1. Carboxylic Acid Ester The non-aqueous electrolyte of the present invention contains a carboxylic acid ester. In the non-aqueous electrolytic solution of the present invention, by using a compound represented by formula (1) or formula (2) described later and a carboxylic acid ester in combination, energy device characteristics can be improved due to a synergistic effect. Although the structure of the carboxylic acid ester is not particularly limited, it is preferably a fluorine-free chain carboxylic ester, more preferably a fluorine-free saturated chain carboxylic ester. The total number of carbon atoms in the carboxylic acid ester is preferably 3 or more, more preferably 4 or more, even more preferably 5 or more, and preferably 7 or less, more preferably 6 or less, still more preferably 5 or less.

Examples of the carboxylic acid ester according to the present invention include the following.
Methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, tert-butyl acetate, methyl propionate, ethyl propionate, n-propyl propionate, isopropyl propionate, n- propionate Butyl, isobutyl propionate, tert-butyl propionate, methyl butyrate, ethyl butyrate, n butyrate
-Propyl, isopropyl butyrate, n-butyl butyrate, isobutyl butyrate, tert-butyl butyrate, methyl isobutyrate, ethyl isobutyrate, n-propyl isobutyrate, isopropyl isobutyrate, n-butyl isobutyrate, isobutyl isobutyrate, isobutyric acid -tert-butyl, methyl valerate, ethyl valerate, n-propyl valerate, isopropyl valerate, n-butyl valerate, isobutyl valerate, tert-butyl valerate, methyl hydroangelate, ethyl hydroangelate, n-propyl hydroangelate, isopropyl hydroangelate, n-butyl hydroangelate, isobutyl hydroangelate, -te hydroangelate
rt-butyl, methyl isovalerate, ethyl isovalerate, n-propyl isovalerate, isopropyl isovalerate, n-butyl isovalerate, isobutyl isovalerate, tert isovalerate
Saturated chain carboxylic acid esters such as t-butyl, methyl pivalate, ethyl pivalate, n-propyl pivalate, isopropyl pivalate, n-butyl pivalate, isobutyl pivalate, tert-butyl pivalate, methyl acrylate , ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, methyl methacrylate, ethyl methacrylate, n- methacrylate
Propyl, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, methyl crotonate, ethyl crotonate, n-propyl crotonate, isopropyl crotonate, n-butyl crotonate, isobutyl crotonate , tert-butyl crotonate, methyl 3-butenoate, ethyl 3-butenoate, n-propyl 3-butenoate, isopropyl 3-butenoate, n-butyl 3-butenoate, isobutyl 3-butenoate, 3- tert-butyl butenoate, methyl 4-pentenoate, ethyl 4-pentenoate, n-propyl 4-pentenoate, isopropyl 4-pentenoate, n-butyl 4-pentenoate, isobutyl 4-pentenoate, 4-pentene -tert-butyl acid, methyl 3-pentenoate, ethyl 3-pentenoate, n-propyl 3-pentenoate, isopropyl 3-pentenoate, n-butyl 3-pentenoate, isobutyl 3-pentenoate, 3-pentenoic acid -
tert-butyl, methyl 2-pentenoate, ethyl 2-pentenoate, n-2-pentenoate
Propyl, isopropyl 2-pentenoate, n-butyl 2-pentenoate, isobutyl 2-pentenoate, tert-butyl 2-pentenoate, methyl 2-propylate, ethyl 2-propinate, n-propyl 2-propyl acid , 2-propyl isopropyl, 2-propyl n
-butyl, isobutyl 2-propylate, tert-butyl 2-propylate, methyl 3-butyrate, ethyl 3-butyrate, n-propyl 3-butyrate, isopropyl 3-butyrate, n- 3-butyrate Butyl, isobutyl 3-butate, tert-butyl 3-butate, methyl 2-butate, ethyl 2-butate, n-propyl 2-butate, isopropyl 2-butate, n-butyl 2-butate , 2-butyric acid isobutyl, 2-butyric acid-te
rt-butyl, methyl 4-pentate, ethyl 4-pentate, n-propyl 4-pentate, isopropyl 4-pentate, n-butyl 4-pentate, isobutyl 4-pentate, tert 4-pentate -butyl, methyl 3-pentate, ethyl 3-pentate, n-propyl 3-pentate, isopropyl 3-pentate, n-butyl 3-pentate, isobutyl 3-pentate, tert-3-pentate Butyl, methyl 2-pentate, ethyl 2-pentate, n-propyl 2-pentate, isopropyl 2-pentate, n-butyl 2-pentate, isobutyl 2-pentate, ter-2-pentate
Unsaturated chain carboxylic acid esters such as t-butyl.

Among these, methyl acetate, ethyl acetate, n-propyl acetate, n-butyl acetate, methyl propionate, ethyl propionate, n-propionate, and
Propyl, n-butyl propionate, methyl butyrate, ethyl butyrate, n-propyl butyrate, n-butyl butyrate, methyl valerate, ethyl valerate, n-propyl valerate, n-butyl valerate, methyl pivalate, pivalic acid Ethyl, n-propyl pivalate, or n-butyl pivalate are preferred, and from the viewpoint of improving ionic conductivity by reducing the viscosity of the electrolyte, methyl acetate, ethyl acetate, n-propyl acetate, n-butyl acetate, methyl propionate, Ethyl propionate, n-propyl propionate, or n-butyl propionate are more preferred, methyl propionate, ethyl propionate, n-propyl propionate, or n-butyl propionate are even more preferred, and ethyl propionate or n-butyl propionate is more preferred. Propyl is particularly preferred.

One type of carboxylic acid ester may be used alone, or two or more types may be used in combination in any combination and ratio.
The amount of carboxylic acid ester (total amount if two or more types) is usually 0.001% by mass or more, preferably 0.01% by mass or more, more preferably 0.1% by mass based on 100% by mass of the non-aqueous electrolyte. % or more, more preferably 0.3% by mass or more, particularly preferably 0.6% by mass or more,
Further, it is usually 70% by mass or less, preferably 30% by mass or less, more preferably 15% by mass or less, still more preferably 5% by mass or less, particularly preferably 3% by mass or less. Within this range, it is easy to suppress an increase in negative electrode resistance and control output characteristics, load characteristics, low temperature characteristics, cycle characteristics, and high temperature storage characteristics.

1-1-2. Compound Represented by Formula (1) The non-aqueous electrolyte of the present invention preferably contains a compound represented by the following formula (1).
In the compound represented by formula (1), no distinction is made between cis-trans isomers and optical isomers, and any of the isomers may be used alone or as a mixture thereof.

In the formula, R ¹ is an unsaturated hydrocarbon group having at least one carbon-carbon unsaturated bond and having 3 to 12 carbon atoms and optionally having a substituent, and R ² has 2 to 10 carbon atoms. is an aliphatic hydrocarbon group.
R ¹ in formula (1) has at least one carbon-carbon unsaturated bond and is not particularly limited as long as it is an unsaturated hydrocarbon group having 3 to 12 carbon atoms, even if it has a substituent. good. This R
¹ is an unsaturated hydrocarbon group having at least one carbon-carbon double bond or an unsaturated hydrocarbon group having at least one carbon-carbon triple bond, preferably at least one carbon-carbon It is an unsaturated hydrocarbon group with a double bond.

More specifically, as ^R1 , the unsaturated hydrocarbon group is an aliphatic unsaturated chain hydrocarbon group having at least one carbon-carbon double bond, an aliphatic unsaturated chain hydrocarbon group having at least one carbon-carbon triple bond, A saturated chain hydrocarbon group, an aromatic hydrocarbon group having at least one aromatic ring is preferable, an aliphatic unsaturated hydrocarbon group having at least one carbon-carbon double bond, an aromatic group having at least one aromatic ring Hydrocarbon groups are more preferred, with at least one carbon-carbon double bond.
More preferred are aliphatic unsaturated hydrocarbon groups. When R ¹ is one of these unsaturated hydrocarbon groups, it is preferable because a negative electrode protective film can be effectively formed and excessive negative electrode reaction can be suppressed.

Furthermore, the unsaturated hydrocarbon group of R ¹ in formula (1) is an unsaturated hydrocarbon group having no substituent other than a hydrocarbon group, or an unsaturated hydrocarbon group in which some H is substituted with F. Preferably, an unsaturated hydrocarbon group having no substituent other than a hydrocarbon group is more preferable. When R ¹ is a group like these, the chelate coordination to the positive electrode metal oxide using ether oxygen and cyano group is not inhibited, so it can be more effectively coordinated to the positive electrode, and the high-temperature storage durability is improved. It is easy to obtain the effects of the present invention such as reducing gas generation after the test, and it is also easy to obtain the effect of improving rate characteristics because the interaction with cations is not inhibited.Furthermore, excess reaction at the negative electrode is also suppressed, so charging and discharging efficiency is improved. This is preferable because it can also improve

Further, the number of carbon atoms in the unsaturated hydrocarbon group of R ¹ in formula (1) is preferably 3 to 12,
3 to 9 are more preferred, and 3 to 7 are even more preferred. If the carbon number is within this range, formula (1)
The compound represented by has excellent solubility in an electrolytic solution.
Specific examples of R ¹ in formula (1) include the following.
<<Aliphatic unsaturated chain hydrocarbon group having at least one carbon-carbon double bond>>

Note that * represents a bonding site with ether oxygen. The same applies below.
<<Aliphatic unsaturated chain hydrocarbon group having at least one carbon-carbon triple bond>>

≪Aromatic hydrocarbon group having at least one aromatic ring≫

^R2 in formula (1) is not particularly limited as long as it is an aliphatic hydrocarbon group having 2 or more and 10 or less carbon atoms; An alkylene group having no substituent is preferable, and an alkylene group having no substituent is more preferable. When R ² is a group like these, chelate coordination to the positive electrode metal oxide using ether oxygen and a cyano group is not inhibited, and therefore coordination to the positive electrode can be performed more effectively, which is preferable. Further, the number of carbon atoms is usually 2 or more, and usually 10 or less, preferably 5 or less, and more preferably 3 or less. This range is preferable because a more stabilizing effect due to the chelate structure can be obtained. Examples of the compound represented by formula (1) include the following compounds.

<<When R ¹ is an aliphatic unsaturated chain hydrocarbon group having at least one carbon-carbon double bond>>

<<When R ¹ is an aliphatic unsaturated chain hydrocarbon group having at least one carbon-carbon triple bond>>

<<When R ¹ is an aromatic hydrocarbon group having at least one aromatic ring>>

Among these, the following compounds are preferred in terms of solubility in the electrolytic solution and ease of production.

Among these, the following compounds are more preferred in terms of ease of coordination to the positive electrode metal and high coordination bond energy.

Among these, the following compounds are most preferred from the viewpoint of low side reactions in energy devices.

The compound represented by formula (1) may be used alone or in combination of two or more. The amount of the compound represented by formula (1) (total amount in the case of two or more types) in the total amount (100% by mass) of the non-aqueous electrolyte is not particularly limited in order to achieve the effects of the present invention. , preferably 0.001% by mass
Above, more preferably 0.01% by mass or more, still more preferably 0.1% by mass or more, particularly preferably 0.3% by mass or more, most preferably 0.6% by mass or more, and preferably The content is 10% by weight or less, more preferably 5% by weight or less, even more preferably 3% by weight or less, particularly preferably 1.5% by weight or less, and most preferably 1.0% by weight or less. Within this range, it is easy to control the charge/discharge efficiency, rate characteristics, gas generation, rate characteristics, initial charge/discharge efficiency, rate characteristics, continuous charging capacity, low temperature characteristics, cycle characteristics, etc. after the durability test.

1-1-3. Compound Represented by Formula (2) The non-aqueous electrolyte of the present invention preferably contains a compound represented by Formula (2). In the compound represented by formula (2), no distinction is made between cis-trans isomers and optical isomers, and either isomer may be used alone or as a mixture thereof.

In the formula, R ³ is an aliphatic hydrocarbon group having 1 to 10 carbon atoms, and a is 0 or 1. However, a plurality of R ³ 's may be the same or different.
^R3 in formula (2) is not particularly limited as long as it is an aliphatic hydrocarbon group having 2 or more and 10 or less carbon atoms, but it can be an alkylene group without a substituent, or a part of the H of the alkylene is substituted with F. An alkylene group is preferable, and an alkylene group having no substituent is more preferable. When R ² is a group such as these, chelate coordination to the positive electrode metal oxide using ether oxygen and cyano group is not inhibited, and therefore coordination to the positive electrode can be performed more effectively, which is preferable. Further, the number of carbon atoms is usually 2 or more, and usually 10 or less, preferably 5 or less, and more preferably 3 or less. This range is preferable because a more stabilizing effect due to the chelate structure can be obtained. Moreover, it is preferable that the plurality of R ³ 's are the same.

In formula (2), a is 0 or 1, but is preferably 1 in view of the solubility of the compound.
Examples of the compound represented by formula (2) include the following compounds.
≪If a is 0≫

≪If a is 1≫

Among these, the following compounds are more preferred in terms of ease of coordination to the positive electrode metal and high coordination bond energy.

Among these, the following compounds are most preferred from the viewpoint of low side reactions in energy devices.

The compound represented by formula (2) may be used alone or in combination of two or more. The amount of the compound represented by formula (2) (total amount in the case of two or more types) in the total amount of the non-aqueous electrolyte (100% by mass) is not particularly limited in order to achieve the effects of the present invention. , preferably 0.001% by mass
Above, more preferably 0.01% by mass or more, still more preferably 0.1% by mass or more, particularly preferably 0.3% by mass or more, most preferably 0.6% by mass or more, and preferably The content is 10% by weight or less, more preferably 5% by weight or less, even more preferably 3% by weight or less, particularly preferably 1.5% by weight or less, and most preferably 1.0% by weight or less. Within this range, it is easy to control the charge/discharge efficiency, rate characteristics, gas generation, rate characteristics, initial charge/discharge efficiency, rate characteristics, continuous charging capacity, low temperature characteristics, cycle characteristics, etc. after the durability test.

The above carboxylic acid ester (hereinafter sometimes referred to as group (A)) and formula (1) or formula (2)
) The content of the above group (A) relative to the total content of at least one compound selected from the group consisting of compounds represented by (hereinafter sometimes referred to as group (B)) is usually 50% by mass or more9
The content is 9.5% by mass or less, preferably 75% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, particularly preferably 98% by mass or more. Within this range, a synergistic effect by the compound of group (A) and the compound of group (B) can be easily obtained.

1-2. Cyclic carbonate having a carbon-carbon unsaturated bond, fluorine-containing cyclic carbonate, sulfur-containing organic compound, phosphorus-containing organic compound, organic compound having a cyano group other than the above formulas (1) and (2), organic compound having an isocyanate group , silicon-containing compounds, monofluorophosphates, difluorophosphates, borates, oxalates, and fluorosulfonates.Aspects of the present invention include the compounds of the groups (A) and (B), as well as carbon- Cyclic carbonates having carbon unsaturated bonds, fluorine-containing cyclic carbonates, sulfur-containing organic compounds, phosphorus-containing organic compounds, organic compounds having cyano groups other than the above formulas (1) and (2), organic compounds having isocyanate groups, silicon Contains at least one compound selected from the group consisting of monofluorophosphates, difluorophosphates, borates, oxalates, and fluorosulfonates (hereinafter sometimes referred to as concomitant additives) It is preferable. This is because by using these in combination, side reactions on the positive and negative electrodes that can be caused by the compounds of group (A) and group (B) can be efficiently suppressed.

Among these, at least one compound selected from the group consisting of a cyclic carbonate having a carbon-carbon unsaturated bond, a fluorine-containing cyclic carbonate, and a sulfur-containing organic compound forms a high-quality composite film on the negative electrode and improves the initial battery characteristics. It is preferable because the battery characteristics after the durability test are improved in a well-balanced manner, and at least one compound selected from the group consisting of a cyclic carbonate having a carbon-carbon unsaturated bond and a fluorine-containing cyclic carbonate is more preferable. The reason is that these compounds, which form a relatively low molecular weight film on the negative electrode, can efficiently prevent deterioration due to side reactions between the (A) group and (B) group compounds because the formed negative electrode film is dense. One example is that it can suppress the By effectively suppressing side reactions in this way, it is possible to simultaneously improve the initial capacity and the rate characteristics after the high temperature storage durability test.

There are no particular restrictions on the method of blending the additives into the electrolytic solution of the present invention. In addition to the method of directly adding the above-mentioned compound to the electrolyte, there is a method of generating a concomitant additive in the battery or in the electrolyte. Examples of the method for generating the combined additive include a method of adding a compound other than the combined additive and generating it by oxidizing or hydrolyzing a battery component such as an electrolytic solution. Furthermore, there is also a method of generating electricity by producing a battery and applying an electrical load such as charging and discharging.

In addition, when combined additives are included in a non-aqueous electrolyte and used to actually produce an energy device, the content in the non-aqueous electrolyte decreases significantly even if the battery is disassembled and the non-aqueous electrolyte is extracted again. There are many cases. Therefore, a non-aqueous electrolytic solution extracted from a battery that can detect even a very small amount of a concomitant additive is considered to be included in the present invention. In addition, when the combined additive is actually used in the production of energy devices as a non-aqueous electrolyte, the non-aqueous electrolyte extracted after disassembling the battery contains only a very small amount of the combined additive. Even though
It is often detected on the positive electrode, negative electrode, or separator, which are other constituent members of the energy device. Therefore, when a combined additive is detected from the positive electrode, negative electrode, and separator, it can be assumed that the total amount was contained in the non-aqueous electrolyte. Under this assumption, it is preferable that the concomitant additives be included within the range described below.

The combined additives will be explained below. However, the explanation in "1-3. Electrolytes" applies to monofluorophosphates, difluorophosphates, borates, oxalates, and fluorosulfonates. Further, regarding the carboxylic acid ester and the compound represented by formula (1) or formula (2) in combination with the above compound, the above description is applied, including illustrations and preferable examples. In addition, in embodiments containing a certain compound, other compounds among the aforementioned compounds may be included.

1-2-1. Cyclic carbonate having a carbon-carbon unsaturated bond The cyclic carbonate having a carbon-carbon unsaturated bond according to the present invention (hereinafter also referred to as "unsaturated cyclic carbonate") includes a carbon-carbon double bond or a carbon-carbon triple bond. There is no particular restriction as long as it is a cyclic carbonate having a bond. A cyclic carbonate having an aromatic ring is also included in the unsaturated cyclic carbonate.

Examples of unsaturated cyclic carbonates include vinylene carbonates, ethylene carbonates substituted with a substituent having an aromatic ring, a carbon-carbon double bond or a carbon-carbon triple bond, phenyl carbonates, vinyl carbonates, allyl carbonates, Examples include catechol carbonates. Among them, vinylene carbonates, or aromatic rings or carbon-
Ethylene carbonates substituted with a substituent having a carbon double bond or a carbon-carbon triple bond are preferred.
Specific examples of unsaturated cyclic carbonates include vinylene carbonate, methylvinylene carbonate, 4,5-dimethylvinylene carbonate, phenylvinylene carbonate,
Vinylene carbonates such as 4,5-diphenylvinylene carbonate, vinyl vinylene carbonate, 4,5-vinyl vinylene carbonate, allyl vinylene carbonate, 4,5-diallyl vinylene carbonate;
Vinyl ethylene carbonate, 4,5-divinyl ethylene carbonate, 4-methyl-5
-vinylethylene carbonate, 4-allyl-5-vinylethylene carbonate, ethynylethylene carbonate, 4,5-diethynylethylene carbonate, 4-methyl-5-
Ethynyl ethylene carbonate, 4-vinyl-5-ethynyl ethylene carbonate, 4-
Allyl-5-ethynylethylene carbonate, phenylethylene carbonate, 4,5-
diphenylethylene carbonate, 4-phenyl-5-vinylethylene carbonate, 4
-Allyl-5-phenylethylene carbonate, allylethylene carbonate, 4,5-
Ethylene carbonates substituted with a substituent having an aromatic ring or a carbon-carbon double bond or a carbon-carbon triple bond, such as diallylethylene carbonate and 4-methyl-5-allylethylene carbonate;
etc. Among them, vinylene carbonate, vinylethylene carbonate, and ethynylethylene carbonate are preferred because they form a more stable interfacial protective film, vinylene carbonate and vinylethylene carbonate are more preferred, and vinylene carbonate is even more preferred.

One type of unsaturated cyclic carbonate may be used alone, or two or more types may be used together in any combination and ratio. The amount of unsaturated cyclic carbonates (total amount if two or more types) can be 0.001% by mass or more, preferably 0.01% by mass or more, more preferably 0.01% by mass or more, based on 100% by mass of the electrolytic solution. .1% by weight or more, and preferably 5% by weight, preferably 4% by weight or less, more preferably 3% by weight or less. Within this range, non-aqueous electrolyte batteries are likely to exhibit sufficient cycle characteristics improvement effects, and also avoid situations such as deterioration of high-temperature storage characteristics, increase in gas generation, and decrease in discharge capacity retention rate. Easy to avoid.

The mass ratio of the compound represented by formula (1) or formula (2) above to the unsaturated cyclic carbonate (total amount if two or more types) is: compound represented by formula (1) or formula (2): unsaturated The ratio of cyclic carbonate is usually 1:100 or more, preferably 10:100 or more, more preferably 20
:100 or more, more preferably 25:100 or more, usually 10000:100 or less, preferably 500:100 or less, more preferably 300:100 or less, still more preferably 100:100 or less, particularly preferably 75: 100 or less, most preferably 50:1
00 or less. Within this range, battery characteristics, particularly durability characteristics, can be significantly improved. Although the principle behind this is not certain, it is thought that by mixing at this ratio, side reactions of the additive on the electrode can be minimized.

1-2-2. Fluorine-containing cyclic carbonate The fluorine-containing cyclic carbonate according to the present invention is not particularly limited as long as it has a cyclic carbonate structure and contains a fluorine atom.
Examples of the fluorine-containing cyclic carbonate include fluorinated cyclic carbonates having an alkylene group having 2 to 6 carbon atoms, and derivatives thereof, such as fluorinated ethylene carbonate (hereinafter referred to as "fluorinated ethylene carbonate") ) and its derivatives. Examples of fluorinated ethylene carbonate derivatives include fluorinated ethylene carbonate substituted with an alkyl group (for example, an alkyl group having 1 to 4 carbon atoms). Among them, fluorinated ethylene carbonate having a fluorine number of 1 to 8 and derivatives thereof are preferred.

Examples of fluorinated ethylene carbonate having a fluorine number of 1 to 8 and its derivatives include monofluoroethylene carbonate, 4,4-difluoroethylene carbonate, 4,5-difluoroethylene carbonate, 4-fluoro-4-methylethylene carbonate, 4,
5-difluoro-4-methylethylene carbonate, 4-fluoro-5-methylethylene carbonate, 4,4-difluoro-5-methylethylene carbonate, 4-(fluoromethyl)-ethylene carbonate, 4-(difluoromethyl)-ethylene carbonate,
4-(trifluoromethyl)-ethylene carbonate, 4-(fluoromethyl)-4-fluoroethylene carbonate, 4-(fluoromethyl)-5-fluoroethylene carbonate, 4-fluoro-4,5-dimethylethylene carbonate, 4 ,5-difluoro-4
, 5-dimethylethylene carbonate, 4,4-difluoro-5,5-dimethylethylene carbonate, and the like. Among these, monofluoroethylene carbonate, 4,4-difluoroethylene carbonate, and 4,5-difluoroethylene carbonate are preferred because they provide high ionic conductivity to the electrolytic solution and can easily form a stable interfacial protective film.

One type of fluorinated cyclic carbonate may be used alone, or two or more types may be used in combination in any combination and ratio. The amount of fluorinated cyclic carbonate (total amount if two or more types) is preferably 0.001% by mass or more, more preferably 0.0% by mass in 100% by mass of the electrolyte.
1% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.5% by mass or more, particularly preferably 1% by mass or more, most preferably 1.2% by mass or more, and preferably The content is 10% by weight or less, more preferably 7% by weight or less, even more preferably 5% by weight or less, particularly preferably 3% by weight or less, most preferably 2% by weight or less. Further, when the fluorinated cyclic carbonate is used as a non-aqueous solvent, the blending amount is preferably 1% by volume or more, more preferably 5% by volume or more, and even more preferably 10% by volume or more based on 100% by volume of the non-aqueous solvent. The content is preferably 50% by volume or less, more preferably 35% by volume or less, even more preferably 25% by volume or less.

The mass ratio of the compound represented by formula (1) or formula (2) above to the fluorinated cyclic carbonate (total amount in the case of two or more types) is: compound represented by formula (1) or formula (2): fluorinated cyclic carbonate The ratio of cyclic carbonate is usually 1:100 or more, preferably 10:100 or more, more preferably 20:100 or more, even more preferably 25:100 or more, and usually 10,000:100 or less, preferably 500:100. The ratio is more preferably 300:100 or less, further preferably 100:100 or less, particularly preferably 75:100 or less, and most preferably 50:100 or less.
:100 or less. Within this range, battery characteristics, particularly durability characteristics, can be significantly improved. Although the principle behind this is not certain, it is thought that by mixing at this ratio, side reactions of the additive on the electrode can be minimized.

1-2-3. Sulfur-Containing Organic Compound The sulfur-containing organic compound according to the present invention is not particularly limited as long as it is an organic compound having at least one sulfur atom in its molecule.
The sulfur-containing organic compound is preferably an organic compound having an S=O group in the molecule, and includes chain sulfonic acid esters, cyclic sulfonic acid esters, chain sulfuric esters, cyclic sulfuric esters, chain sulfite esters, and cyclic sulfonic acid esters. Examples include sulfite esters. However, those corresponding to fluorosulfonates are not included in "1-2-3. Sulfur-containing organic compounds" but are included in "fluorosulfonates" which are electrolytes described later. Among these, chain sulfonic acid esters, cyclic sulfonic acid esters, chain sulfuric esters, cyclic sulfuric esters, chain sulfites, and cyclic sulfite esters are preferable, and compounds having _two S(=O) groups are more preferable, and Preferred are chain sulfonic esters and cyclic sulfonic esters,
Particularly preferred are cyclic sulfonic acid esters. A battery using the electrolyte of the present invention in combination with a sulfur-containing organic compound can have improved durability characteristics.
Specific examples of sulfur-containing organic compounds include the following.

≪Chained sulfonic acid ester≫
Fluorosulfonic acid esters such as methyl fluorosulfonate and ethyl fluorosulfonate;
Methyl methanesulfonate, ethyl methanesulfonate, 2-propynyl methanesulfonate, 3-butynyl methanesulfonate, busulfan, methyl 2-(methanesulfonyloxy)propionate, ethyl 2-(methanesulfonyloxy)propionate, 2- 2-propynyl (methanesulfonyloxy)propionate, 3-butynyl 2-(methanesulfonyloxy)propionate, methyl methanesulfonyloxyacetate, ethyl methanesulfonyloxyacetate, 2-propynyl methanesulfonyloxyacetate and 3-methanesulfonyloxyacetate
- methanesulfonic acid esters such as butynyl;
Methyl vinylsulfonate, ethyl vinylsulfonate, allyl vinylsulfonate, propargyl vinylsulfonate, methyl allylsulfonate, ethyl allylsulfonate, allyl allylsulfonate, propargyl allylsulfonate, and 1,2-bis(vinylsulfonyloxy) ) alkenyl sulfonic acid esters such as ethane;
Methoxycarbonylmethyl methanedisulfonate, ethoxycarbonylmethyl methanedisulfonate, 1-methoxycarbonylethyl methanedisulfonate, 1-methanedisulfonate
Ethoxycarbonylethyl, methoxycarbonylmethyl 1,2-ethanedisulfonate, 1
,2-ethanedisulfonic acid ethoxycarbonylmethyl,1,2-ethanedisulfonic acid 1-
Methoxycarbonylethyl, 1-ethoxycarbonylethyl 1,2-ethanedisulfonate, methoxycarbonylmethyl 1,3-propanedisulfonate, ethoxycarbonylmethyl 1,3-propanedisulfonate, 1-methoxycarbonyl 1,3-propanedisulfonate Ethyl, 1-ethoxycarbonylethyl 1,3-propanedisulfonate, methoxycarbonylmethyl 1,3-butanedisulfonate, ethoxycarbonylmethyl 1,3-butanedisulfonate, 1-methoxycarbonylethyl 1,3-butanedisulfonate, Alkyldisulfonic acid esters such as 1-ethoxycarbonylethyl 1,3-butanedisulfonic acid;

≪Cyclic sulfonic acid ester≫
1,3-propane sultone, 1-fluoro-1,3-propane sultone, 2-fluoro-1,3-propane sultone, 3-fluoro-1,3-propane sultone, 1-methyl-
1,3-propane sultone, 2-methyl-1,3-propane sultone, 3-methyl-1,
3-propane sultone, 1-propene-1,3-sultone, 2-propene-1,3-sultone, 1-fluoro-1-propene-1,3-sultone, 2-fluoro-1-propene-
1,3-sultone, 3-fluoro-1-propene-1,3-sultone, 1-fluoro-2
-Propene-1,3-sultone, 2-fluoro-2-propene-1,3-sultone, 3-
Fluoro-2-propene-1,3-sultone, 1-methyl-1-propene-1,3-sultone, 2-methyl-1-propene-1,3-sultone, 3-methyl-1-propene-1,
3-sultone, 1-methyl-2-propene-1,3-sultone, 2-methyl-2-propene-1,3-sultone, 3-methyl-2-propene-1,3-sultone, 1,4- Sultone compounds such as butane sultone and 1,5-pentane sultone;
Cyclic disulfonate compounds such as methylene methane disulfonate and ethylene methane disulfonate;

≪Chained sulfate ester≫
Dialkyl sulfate compounds such as dimethyl sulfate, ethyl methyl sulfate and diethyl sulfate.

≪Cyclic sulfate ester≫
1,2-ethylene sulfate, 1,2-propylene sulfate, 1,3-propylene sulfate, 1,2-butylene sulfate, 1,3-butylene sulfate, 1,
Alkylene sulfate compounds such as 4-butylene sulfate, 1,2-pentylene sulfate, 1,3-pentylene sulfate, 1,4-pentylene sulfate and 1,5-pentylene sulfate.

≪Chained sulfite ester≫
Dialkyl sulfite compounds such as dimethyl sulfite, ethyl methyl sulfite and diethyl sulfite.

≪Cyclic sulfite ester≫
1,2-ethylene sulfite, 1,2-propylene sulfite, 1,3-propylene sulfite, 1,2-butylene sulfite, 1,3-butylene sulfite, 1,
Alkylene sulfite compounds such as 4-butylene sulfite, 1,2-pentylene sulfite, 1,3-pentylene sulfite, 1,4-pentylene sulfite and 1,5-pentylene sulfite.

Among these, methyl 2-(methanesulfonyloxy)propionate, ethyl 2-(methanesulfonyloxy)propionate, 2-(methanesulfonyloxy)propionate
-Propynyl, 1-methoxycarbonylethyl propanedisulfonate, 1-ethoxycarbonylethyl propanedisulfonate, 1-methoxycarbonylethyl butanedisulfonate, 1-ethoxycarbonylethyl butanedisulfonate, 1,3-propane sultone, 1-
Propene-1,3-sultone, 1,4-butanesultone, 1,2-ethylene sulfate, 1,2-ethylene sulfite, methyl methanesulfonate and ethyl methanesulfonate are preferred from the viewpoint of improving initial efficiency, and propane disulfone 1-methoxycarbonylethyl acid, 1-ethoxycarbonylethyl propanedisulfonate, 1-methoxycarbonylethyl butanedisulfonate, 1-ethoxycarbonylethyl butanedisulfonate, 1,3-propane sultone, 1-propene-1,3-sultone , 1,2-ethylene sulfate, 1,
2-ethylene sulfite is more preferred, 1,3-propane sultone, 1-propene-
1,3-sultone is more preferred.

One type of sulfur-containing organic compound may be used alone, or two or more types may be used together in any combination and ratio. The content of the sulfur-containing organic compound (total amount if two or more types) is usually 0.001% by mass or more, preferably 0.01% by mass or more, more preferably 0.01% by mass or more, based on 100% by mass of the electrolyte. 1% by mass or more, particularly preferably 0.3% by mass or more, particularly preferably 0.6% by mass or more, and usually 10% by mass or less, preferably 5% by mass.
The following is more preferably 3% by mass or less, still more preferably 2% by mass or less, particularly preferably 1.
It is 5% by weight or less, most preferably 1.0% by weight or less. Within this range, the output characteristics,
Easy to control load characteristics, low temperature characteristics, cycle characteristics, high temperature storage characteristics, etc.

1-2-4. Phosphorus-Containing Organic Compound The phosphorus-containing organic compound according to the present invention is not particularly limited as long as it is an organic compound having at least one phosphorus atom in its molecule. A battery using the electrolyte of the present invention in combination with a phosphorus-containing organic compound can have improved durability characteristics.
As the phosphorus-containing organic compound, phosphoric esters, phosphonic esters, phosphinic esters, and phosphorous esters are preferred, phosphoric esters and phosphonic esters are more preferred, and phosphonic esters are still more preferred.
Examples of phosphorus-containing organic compounds include the following.

≪Phosphate ester≫
Containing vinyl groups such as dimethyl vinyl phosphate, diethyl vinyl phosphate, dipropyl vinyl phosphate, dibutyl vinyl phosphate, dipentyl vinyl phosphate, methyl divinyl phosphate, ethyl divinyl phosphate, propyl divinyl phosphate, butyl divinyl phosphate, pentyl divinyl phosphate, and trivinyl phosphate. Compound;

Contains an allyl group such as allyl dimethyl phosphate, allyl diethyl phosphate, allyl dipropyl phosphate, allyl dibutyl phosphate, allyl dipentyl phosphate, diallyl methyl phosphate, diallyl ethyl phosphate, diallyl propyl phosphate, diallyl butyl phosphate, diallypentyl phosphate, and triallyl phosphate. Compound;

Propargyl dimethyl phosphate, propargyl diethyl phosphate, propargyl dipropyl phosphate, propargyl dibutyl phosphate, propargyl dipentyl phosphate, dipropargyl methyl phosphate, dipropargyl ethyl phosphate, dipropargyl propyl phosphate, dipropargyl butyl phosphate, dipropargyl pentyl phosphate and tripropargyl phosphate, etc. A compound having a propargyl group;

2-acryloyloxymethyl dimethyl phosphate, 2-acryloyloxymethyl diethyl phosphate, 2-acryloyloxymethyl dipropyl phosphate, 2-acryloyloxymethyl dibutyl phosphate, 2-acryloyloxymethyl dipentyl phosphate, bis(2-acryloyloxymethyl)methyl Phosphate, bis(2)
-Acryloyloxymethyl)ethyl phosphate, bis(2-acryloyloxymethyl)propyl phosphate, bis(2-acryloyloxymethyl)butyl phosphate, bis(2-acryloyloxymethyl)pentyl phosphate and tris(2-acryloyloxymethyl)phosphate A compound having a 2-acryloyloxymethyl group;

2-Acryloyloxyethyl dimethyl phosphate, 2-acryloyloxyethyl diethyl phosphate, 2-acryloyloxyethyl dipropyl phosphate, 2-acryloyloxyethyl dibutyl phosphate, 2-acryloyloxyethyl dipentyl phosphate, bis(2-acryloyloxyethyl)methyl Phosphate, bis(2)
- acryloyloxyethyl) ethyl phosphate, bis(2-acryloyloxyethyl) propyl phosphate, bis(2-acryloyloxyethyl) butyl phosphate and bis(2-acryloyloxyethyl) pentyl phosphate and tris(2-acryloyloxyethyl) phosphate

≪Phosphonate ester≫
Trimethyl phosphonoformate, methyl diethylphosphonoformate, methyl dipropylphosphonoformate, methyl dibutylphosphonoformate, triethylphosphonoformate, ethyl dimethylphosphonoformate, ethyl dipropylphosphonoformate, ethyl Dibutylphosphonoformate, tripropyl phosphonoformate, propyl dimethylphosphonoformate, propyl diethylphosphonoformate, propyl dibutylphosphonoformate, tributyl phosphonoformate, butyl dimethylphosphonoformate, butyl diethylphosphonoformate Noformate, Butyl dipropylphosphonoformate, Methyl bis(2,2,2-trifluoroethyl)phosphonoformate, Ethyl bis(2,2,2-trifluoroethyl)phosphonoformate, Propyl bis (2,2,2-trifluoroethyl)phosphonoformate, butyl bis(2,2,2-trifluoroethyl)phosphonoformate, trimethyl phosphonoacetate, methyl diethylphosphonoacetate, methyl dipropylphosphonoacetate Acetate, Methyl dibutylphosphonoacetate, Triethyl phosphonoacetate, Ethyl dimethylphosphonoacetate, Ethyl dipropylphosphonoacetate, Ethyl dibutylphosphonoacetate, Tripropyl phosphonoacetate, Propyl dimethylphosphonoacetate, Propyl diethylphosphonoacetate, Propyl dibutylphosphonoacetate, tributyl phosphonoacetate, butyl dimethylphosphonoacetate, butyl diethylphosphonoacetate, butyl dipropylphosphonoacetate, methyl bis(2,2,2-trifluoroethyl)phosphonoacetate, ethyl bis( 2,2,2-trifluoroethyl)phosphonoacetate, propyl bis(
2,2,2-trifluoroethyl)phosphonoacetate, butyl bis(2,2,2-trifluoroethyl)phosphonoacetate, allyl dimethylphosphonoacetate, allyl diethylphosphonoacetate, 2-propynyl dimethylphosphonoacetate , 2-propynyl diethylphosphonoacetate, trimethyl 3-phosphonopropionate, methyl 3-(diethylphosphono)propionate, methyl 3-(dipropylphosphono)
Propionate, methyl 3-(dibutylphosphono)propionate, triethyl 3-
Phosphonopropionate, ethyl 3-(dimethylphosphono)propionate, ethyl
3-(dipropylphosphono)propionate, ethyl 3-(dibutylphosphono)propionate, tripropyl 3-phosphonopropionate, propyl 3-(dimethylphosphono)propionate, propyl 3-(diethylphosphono)propionate, Propyl 3-(dibutylphosphono)propionate, tributyl 3-phosphonopropionate, butyl 3-(dimethylphosphono)propionate, butyl 3-(diethylphosphono)propionate, butyl 3-(dipropylphosphono)propionate, Methyl 3-
(bis(2,2,2-trifluoroethyl)phosphono)propionate, ethyl 3-(
Bis(2,2,2-trifluoroethyl)phosphono)propionate, propyl 3-(
Bis(2,2,2-trifluoroethyl)phosphono)propionate, Butyl 3-(bis(2,2,2-trifluoroethyl)phosphono)propionate, Trimethyl 4-phosphonobutyrate, Methyl 4-(diethylphosphono) ) Butyrate, methyl 4-(dipropylphosphono)butyrate, methyl 4-(dibutylphosphono)butyrate, triethyl 4-phosphonobutyrate, ethyl 4-(dimethylphosphono)butyrate, ethyl
4-(dipropylphosphono)butyrate, ethyl 4-(dibutylphosphono)butyrate, tripropyl 4-phosphonobutyrate, propyl 4-(dimethylphosphono)butyrate, propyl 4-(diethylphosphono)butyrate, propyl 4-(dibutylphosphono)butyrate, tributyl 4-phosphonobutyrate, butyl 4-(dimethylphosphono)butyrate, butyl 4-(diethylphosphono)butyrate, butyl 4-(dipropylphosphono)butyrate, etc.

Among these, from the viewpoint of improving battery characteristics, triallyl phosphate, tris(2-acryloyloxyethyl) phosphate, trimethyl phosphonoacetate, triethylphosphonoacetate, 2-propynyl dimethylphosphonoacetate, 2-propynyl
Diethylphosphonoacetate is preferred.
One type of phosphorus-containing organic compound may be used alone, or two or more types may be used together in any combination and ratio. The content of the phosphorus-containing organic compound (total amount in the case of two or more types) is usually 0.001% by mass or more, preferably 0.01% by mass or more, more preferably 0.01% by mass or more, based on 100% by mass of the electrolyte. 1% by mass or more, more preferably 0.4% by mass or more, particularly preferably 0.6% by mass or more, and usually 10% by mass or less, preferably 5% by mass or less,
The content is more preferably 3% by mass or less, still more preferably 2% by mass or less, particularly preferably 1.2% by mass or less, most preferably 0.9% by mass or less. Within this range, output characteristics, load characteristics, low temperature characteristics, cycle characteristics, high temperature storage characteristics, etc. can be easily controlled.

1-2-5. Organic compounds having cyano groups other than the above formulas (1) and (2) Organic compounds having cyano groups other than the above formulas (1) and (2) according to the present invention include:
It is not particularly limited as long as it is an organic compound having a cyano group other than those of formulas (1) and (2) that has at least one cyano group in its molecule. Among these, organic compounds having cyano groups other than those of formulas (1) and (2) having two or three cyano groups are preferred. Formula (1
) and (2) A battery using the electrolytic solution of the present invention containing an organic compound having a cyano group other than (2) can have improved durability characteristics.
Specific examples of organic compounds having a cyano group other than those of formulas (1) and (2) include the following.

≪Compound having one cyano group≫
Propionitrile, butyronitrile, pentanenitrile, hexanenitrile, heptanenitrile, octanenitrile, pelargononitrile, decanenitrile, undecanenitrile, dodecanenitrile, cyclopentanecarbonitrile, cyclohexanecarbonitrile, acrylonitrile, methacrylonitrile, crotononitrile, 3-methylcrotononitrile, 2-methyl-2-butenenitrile, 2-pentenenitrile, 2-methyl-2-pentenenitrile, 3-methyl-2-pentenenitrile and 2-hexenenitrile;

≪Compound having two cyano groups≫
Malononitrile, succinonitrile, glutaronitrile, adiponitrile, pimelonitrile, suberonitrile, azelanitrile, sebaconitrile, undecanedinitrile, dodecanedinitrile, methylmalononitrile, ethylmalononitrile, isopropylmalononitrile, tert-butylmalononitrile, methylsuccinonitrile , 2,2-dimethylsuccinonitrile, 2,3-dimethylsuccinonitrile, 2,3,3-trimethylsuccinonitrile, 2,2,3,3-tetramethylsuccinonitrile, 2,3-diethyl- 2,
3-dimethylsuccinonitrile, 2,2-diethyl-3,3-dimethylsuccinonitrile, bicyclohexyl-1,1-dicarbonitrile, bicyclohexyl-2,2-dicarbonitrile, bicyclohexyl-3,3 -dicarbonitrile, 2,5-dimethyl-2,5-
Hexane dicarbonitrile, 2,3-diisobutyl-2,3-dimethylsuccinonitrile, 2,2-diisobutyl-3,3-dimethylsuccinonitrile, 2-methylglutaronitrile, 2,3-dimethylglutaronitrile , 2,4-dimethylglutaronitrile, 2,2
, 3,3-tetramethylglutaronitrile, 2,2,4,4-tetramethylglutaronitrile, 2,2,3,4-tetramethylglutaronitrile, 2,3,3,4-tetramethylglutaronitrile Talonitrile, maleonitrile, fumaronitrile, 1,4-dicyanopentane, 2,
6-dicyanoheptane, 2,7-dicyanooctane, 2,8-dicyanononane, 1,6-
Dicyanodecane, 1,2-didianobenzene, 1,3-dicyanobenzene, 1,4-dicyanobenzene, 3,3'-(ethylenedioxy)dipropionitrile, 3,3'-(ethylenedithio)dipropio Nitrile and 3,9-bis(2-cyanoethyl)-2,4,8,
10-tetraoxaspiro[5,5]undecane;

≪Compound having three cyano groups≫
Tris(2-cyanoethyl)amine, 1,2,3-propane tricarbonitrile, 1,2
, 3-butanetricarbonitrile, 1,2,3-pentanetricarbonitrile, 1,3,4-
Pentane tricarbonitrile, 1,3,5-pentane tricarbonitrile, 1,3,6-pentane tricarbonitrile;
Among these, malononitrile, succinonitrile, glutaronitrile, adiponitrile, pimelonitrile, suberonitrile, azelanitrile, sebaconitrile, undecanedinitrile, dodecanedinitrile and 3,9-bis(2-cyanoethyl)-2,4,8,1
0-tetraoxaspiro[5,5]undecane, fumaronitrile, and 1,3,5-pentanetricarbonitrile are preferred from the viewpoint of improving high-temperature storage durability. Furthermore, succinonitrile,
Glutaronitrile, adiponitrile, pimelonitrile, suberonitrile, glutaronitrile, 3,9-bis(2-cyanoethyl)-2,4,8,10-tetraoxaspiro[5,
5] Undecane and 1,3,5-pentanetricarbonitrile are more preferable because they have a particularly excellent effect of improving high-temperature storage durability characteristics and are less susceptible to deterioration due to side reactions at the electrode.

The organic compounds having a cyano group other than those of formulas (1) and (2) may be used alone or in combination of two or more in any combination and ratio. The content of organic compounds having a cyano group other than formulas (1) and (2) (total amount in the case of two or more types) is usually 0.001% by mass or more in 100% by mass of the electrolyte, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.4% by mass or more, particularly preferably 0.6% by mass
or more, and usually 10% by mass or less, preferably 5% by mass or less, more preferably 3% by mass or less, still more preferably 2% by mass or less, particularly preferably 1.2% by mass or less, and most preferably It is 0.9% by mass or less. Within this range, output characteristics, load characteristics, low temperature characteristics, cycle characteristics, high temperature storage characteristics, etc. can be easily controlled.

1-2-6. Organic compound having an isocyanate group The organic compound having an isocyanate group according to the present invention is not particularly limited as long as it has at least one isocyanate group in the molecule, but the number of isocyanate groups in one molecule is Preferably it is 1 or more and 4 or less, more preferably 2 or more and 3 or less, and even more preferably 2. A battery using the electrolyte of the present invention in combination with an organic compound having an isocyanate group can have improved durability characteristics.

Examples of the organic compound having an isocyanate group include the following.
Isocyanate groups such as methyl isocyanate, ethyl isocyanate, propyl isocyanate, isopropylisocyanate, butyl isocyanate, tertiary butyl isocyanate, pentyl isocyanate, hexyl isocyanate, cyclohexyl isocyanate, vinyl isocyanate, allyl isocyanate, ethynyl isocyanate, propargyl isocyanate, phenyl isocyanate, fluorophenyl isocyanate An organic compound having one;

Monomethylene diisocyanate, dimethylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, heptamethylene diisocyanate, octamethylene diisocyanate, nonamethylene diisocyanate, decamethylene diisocyanate, dodecamethylene diisocyanate, 1,3-diisocyanate Natopropane, 1,4-diisocyanato-2
-butene, 1,4-diisocyanato-2-fluorobutane, 1,4-diisocyanato-2
,3-difluorobutane, 1,5-diisocyanato-2-pentene, 1,5-diisocyanato-2-methylpentane, 1,6-diisocyanato-2-hexene, 1,6-diisocyanato-3-hexene, 1,6 -diisocyanato-3-fluorohexane, 1,6-diisocyanato-3,4-difluorohexane, toluene diisocyanate, xylene diisocyanate, tolylene diisocyanate, 1,2-bis(isocyanatomethyl)cyclohexane, 1,3-bis(isocyanatomethyl)cyclohexane cyclohexane, 1,4-bis(isocyanatomethyl)cyclohexane, 1,2-diisocyanatocyclohexane, 1,3-diisocyanatocyclohexane, 1,4-diisocyanatocyclohexane, dicyclohexylmethane-1,1 '-diisocyanate, dicyclohexylmethane-2,2'-diisocyanate, dicyclohexylmethane-3,3'-diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, bicyclo[2.2.1]heptane-2,5-diylbis( methyl isocyanate), bicyclo[2.2.1]heptane-2,6-diylbis(methyl isocyanate), isophorone diisocyanate, carbonyl diisocyanate, 1,
4-diisocyanatobutane-1,4-dione, 1,5-diisocyanatopentane-1,5
- dione, an organic compound having two isocyanate groups such as 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate;
etc.

Among these, monomethylene diisocyanate, dimethylene diisocyanate, trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, heptamethylene diisocyanate, octamethylene diisocyanate, nonamethylene diisocyanate, decamethylene diisocyanate, dodecamethylene diisocyanate, 1, 3-bis(isocyanatomethyl)cyclohexane, dicyclohexylmethane-4,4'-diisocyanate, bicyclo[2.2.1]
Heptane-2,5-diylbis(methyl isocyanate), bicyclo[2.2.1]heptane-2,6-diylbis(methylisocyanate), isophorone diisocyanate, 2,
Organic compounds having two isocyanate groups such as 2,4-trimethylhexamethylene diisocyanate and 2,4,4-trimethylhexamethylene diisocyanate are preferred from the viewpoint of improving storage properties, and hexamethylene diisocyanate, 1,3- Bis(isocyanatomethyl)cyclohexane, dicyclohexylmethane-4,4'-diisocyanate, bicyclo[
2.2.1] Heptane-2,5-diylbis(methyl isocyanate), bicyclo[2.
2.1] Heptane-2,6-diylbis(methyl isocyanate), isophorone diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate are more preferred, and 1 , 3-bis(isocyanatomethyl)cyclohexane, dicyclohexylmethane-4,4'-diisocyanate, bicyclo[2.2.1]heptane-2,5-diylbis(methylisocyanate), bicyclo[2
．． 2.1] Heptane-2,6-diylbis(methyl isocyanate) is more preferred.

The organic compound having an isocyanate group may be a trimer compound derived from a compound having at least two isocyanate groups in the molecule, or an aliphatic polyisocyanate obtained by adding a polyhydric alcohol thereto. For example, the following formulas (2-6-1) to (2-6
Biuret, isocyanurate, adduct, and bifunctional type modified polyisocyanates having the basic structure shown in -4) can be mentioned.

In formulas (2-6-1) to (2-6-4), R and R' are each independently any divalent or trivalent hydrocarbon group (for example, a tetramethylene group, a hexamethylene group, ). )
Organic compounds having at least two isocyanate groups in the molecule also include so-called blocked isocyanates, which are blocked with a blocking agent to improve storage stability. Blocking agents include alcohols, phenols, organic amines, oximes, and lactams, and specifically include n-butanol, phenol, tributylamine, diethylethanolamine, methylethylketoxime, and ε-caprolactam. etc. can be mentioned.

In order to accelerate reactions based on organic compounds having isocyanate groups and obtain higher effects, metal catalysts such as dibutyltin dilaurate and 1,8-diazabicyclo[5.4
．． It is also preferable to use an amine catalyst such as undecene-7.
The organic compounds having an isocyanate group may be used alone or in combination of two or more in any ratio. The content of the organic compound having an isocyanate group (in the case of two or more types, the total amount) can be 0.001% by mass or more, preferably 0.1% by mass or more, and more preferably 0.1% by mass or more in 100% by mass of the electrolytic solution. It is preferably 0.3% by mass or more, and can be 10% by mass or less, preferably 5% by mass or less, more preferably 3% by mass.
It is as follows. Within this range, it is easy to control output characteristics, load characteristics, low temperature characteristics, cycle characteristics, high temperature storage characteristics, etc.

1-2-7. Silicon-Containing Compound The silicon-containing compound according to the present invention is not particularly limited as long as it is a compound having at least one silicon atom in the molecule. A battery using the electrolyte of the present invention in combination with a silicon-containing compound can have improved durability characteristics.
Examples of silicon-containing compounds include the following compounds.

Tris(trimethylsilyl) borate, tris(trimethoxysilyl) borate, tris(triethylsilyl) borate, tris(triethoxysilyl) borate, tris(dimethylvinylsilyl) borate and tris(diethylvinylsilyl) borate Boric acid compounds such as; Tris phosphate (trimethylsilyl), Tris phosphate (triethylsilyl), Tris phosphate (
Tris phosphate (triphenylsilyl), tris phosphate (trimethoxysilyl), tris phosphate (triethoxysilyl), tris phosphate (triphenoxysilyl), tris phosphate (dimethylvinylsilyl) and phosphoric acid compounds such as tris(diethylvinylsilyl) phosphate;

Tris phosphite (trimethylsilyl), tris phosphite (triethylsilyl), tris phosphite (tripropylsilyl), tris phosphite (triphenylsilyl), tris phosphite (trimethoxysilyl), phosphorous acid Phosphite compounds such as tris (triethoxysilyl), tris phosphite (triphenoxysilyl), tris phosphite (dimethylvinylsilyl) and tris phosphite (diethylvinylsilyl); trimethylsilyl methanesulfonate,
Sulfonic acid compounds such as trimethylsilyl tetrafluoromethanesulfonate;
Hexamethyldisilane, hexaethyldisilane, 1,1,2,2-tetramethyldisilane, 1,1,2,2-tetraethyldisilane, 1,2-diphenyltetramethyldisilane and 1,1,2,2-tetraphenyl Disilane compounds such as disilane;
etc.

Among these, tris(trimethylsilyl) borate, tris(trimethylsilyl) phosphate, tris(trimethylsilyl) phosphite, trimethylsilyl methanesulfonate, trimethylsilyl tetrafluoromethanesulfonate, hexamethyldisilane, hexaethyldisilane, 1,2- Diphenyltetramethyldisilane and 1,1,2,2-tetraphenyldisilane are preferred, and tris(trimethylsilyl) borate, tris(trimethylsilyl) phosphate, tris(trimethylsilyl) phosphite and hexamethyldisilane are more preferred.

One silicon-containing compound may be used alone, or two or more silicon-containing compounds may be used in any combination and ratio. The silicon-containing compound (total amount if two or more) is usually 0.001% by mass or more, preferably 0.1% by mass or more, more preferably 0.3% by mass or more in 100% by mass of the electrolyte. The content is usually 10% by mass or less, preferably 5% by mass or less, more preferably 3% by mass or less. Within this range, it is easy to control output characteristics, load characteristics, low temperature characteristics, cycle characteristics, high temperature storage characteristics, etc.

1-3. Electrolyte The electrolyte according to the present invention is not particularly limited, and any known electrolyte can be used. In the case of lithium secondary batteries, lithium salts are usually used. Specifically, LiPF
₆ , LiBF4 _{, LiClO4} , _LiAlF4 , _LiSbF6 , _LiTaF6 , LiWF
Inorganic lithium salts such as ₇ ; Lithium tungstates such as LiWOF ₅ ; HCO ₂ Li, C
_{H3CO2Li , CH2FCO2Li , CHF2CO2Li , CF3CO2Li , CF3
CH2CO2Li , CF3CF2CO2Li , CF3CF2CF2CO2Li , CF3C _ _ _}
Carboxylic acid lithium salts such as F ₂ CF ₂ CF ₂ CO ₂ Li; FSO ₃ Li, CH ₃ SO _{3
Li , CH2FSO3Li , CHF2SO3Li} , _{CF3SO3Li , CF3CF2SO
3} Li, sulfonic acid lithium salts such as CF ₃ CF ₂ CF ₂ SO ₃ Li, CF ₃ CF ₂ CF ₂ CF ₂ SO ₃ Li; LiN(FCO) ₂ , LiN(FCO) (FSO ₂ ), LiN(F
_SO2 ) ₂ , LiN( _FSO2 )( _{CF3SO2 )} , LiN( _{CF3SO2 ) 2} , LiN
(C ₂ F ₅ SO ₂ ) ₂ , lithium cyclic 1,2-perfluoroethane disulfonylimide,
Lithium cyclic 1,3-perfluoropropanedisulfonylimide, LiN(CF ₃ SO ₂
) (C ₄ F ₉ SO ₂ ); LiC(FSO ₂ ) ₃ , LiC(CF ₃
Lithium methide salts such as _SO2 ) ₃ , LiC( _{C2F5SO2 ) 3} ; Lithium ( _malonato )borate salts such as lithium bis(malonato)borate and lithium difluoro(malonato)borate; lithium tris(malonato)phosphate, lithium Lithium (such as difluorobis(malonato)phosphate, lithium tetrafluoro(malonato)phosphate)
Malonato) phosphate salts; Others, LiPF ₄ (CF ₃ ) ₂ , LiPF ₄ (C ₂ F ₅
) ₂ , LiPF ₄ (CF ₃ SO ₂ ) ₂ , LiPF ₄ (C ₂ F ₅ SO ₂ ) ₂ , LiBF ₃ C
F ₃ , LiBF ₃ C ₂ F ₅ , LiBF ₃ C ₃ F ₇ , LiBF ₂ (CF ₃ ) ₂ , LiBF ₂
Fluorine-containing organic lithium salts such as (C ₂ F ₅ ) ₂ , LiBF ₂ (CF ₃ SO ₂ ) ₂ , LiBF ₂ (C ₂ F ₅ SO ₂ ) ₂ ; lithium difluorooxalatoborate, lithium bis(oxalato)borate, etc. lithium oxalatoborate salts;
Lithium oxalatophosphate salts such as lithium tetrafluorooxalatophosphate, lithium difluorobis(oxalato)phosphate, and lithium tris(oxalato)phosphate; and the like.

Among these, LiPF ₆ , LiSbF ₆ , LiTaF ₆ , FSO ₃ Li, CF ₃ S
O ₃ Li, LiN(FSO ₂ ) ₂ , LiN(FSO ₂ )(CF ₃ SO ₂ ), LiN(CF
₃ SO ₂ ) ₂ , LiN(C ₂ F ₅ SO ₂ ) ₂ , lithium cyclic 1,2-perfluoroethanedisulfonylimide, lithium cyclic 1,3-perfluoropropanedisulfonylimide,
LiC( _FSO2 ) ₃ , LiC( _CF3SO2 ) ₃ , _LiC ( _{C2F5SO2 ) 3} , _Li
BF ₃ CF ₃ , LiBF ₃ C ₂ F ₅ , LiPF ₃ (CF ₃ ) ₃ , LiPF ₃ (C ₂ F ₅ )
_3. Lithium difluorooxalatoborate, lithium bis(oxalato)borate, lithium difluorobis(oxalato)phosphate, etc. are preferred because they are effective in improving output characteristics, high rate charge/discharge characteristics, high temperature storage characteristics, cycle characteristics, etc. Also, Li
More preferred are _PF6 , _FSO3Li , LiN( _FSO2 ) ₂ , LiN( _{CF3SO2 ) 2} , lithium difluorooxalatoborate, lithium bis(oxalato)borate, and lithium difluorobis(oxalato)phosphate, _LiPF6 , FSO ₃ Li, LiN
(FSO ₂ ) ₂ and lithium bis(oxalato)borate are more preferable because they have the effect of further improving output characteristics, high rate charge/discharge characteristics, high temperature storage characteristics, cycle characteristics, etc., and from the viewpoint of redox stability of the electrolyte. LiPF ₆ is most preferred.

The ratio of the molar content of the compound represented by formula (1) or formula (2) to the molar content of the electrolyte contained in the non-aqueous electrolytic solution is not particularly limited in order to achieve the effects of the present invention. , usually 0.043 or more, preferably 0.050 or more, more preferably 0.075 or more, even more preferably 0.080 or more, particularly preferably 0.100 or more, and usually 0.935 or less, preferably 0.850 or less, more preferably 0.760 or less, even more preferably 0.3
00 or less, particularly preferably 0.200 or less. Within this range, battery characteristics, especially continuous charge durability characteristics, can be significantly improved. I am not sure about this principle, but
It is thought that this is because mixing at this ratio facilitates efficient complex formation with the decomposition products of the electrolyte. Note that the ratio of the molar content of the compound represented by formula (1) or formula (2) to the molar content of the electrolyte refers to the ratio of the molar content of the compound represented by formula (1) or formula (2) to the molar content of the electrolyte. It represents the value divided by the molar content, and is an index representing the number of molecules of the compound represented by formula (1) or formula (2) with respect to one molecule of electrolyte.

The concentration of these electrolytes in the non-aqueous electrolyte is not particularly limited as long as it does not impair the effects of the present invention, but it is important to keep the electrical conductivity of the electrolyte within a good range and ensure good battery performance. From this point, the total molar concentration of lithium in the non-aqueous electrolyte is preferably 0.25 mol/L.
Above, it is more preferably 0.5 mol/L or more, still more preferably 1.1 mol/L or more, and preferably 3.0 mol/L or less, more preferably 2.5 mol/L or less, still more preferably 2. It is 0 mol/L or less. Within this range, the amount of lithium, which is a charged particle, is not too small and the viscosity can be kept within an appropriate range, making it easy to ensure good electrical conductivity.

When two or more electrolytes are used together, it is also preferred that at least one of them is a salt selected from the group consisting of monofluorophosphates, difluorophosphates, borates, oxalates, and fluorosulfonates. More preferably, it is a salt selected from the group consisting of monofluorophosphate, difluorophosphate, oxalate, and fluorosulfonate. Among these, lithium salts are preferred. The salt selected from the group consisting of monofluorophosphate, difluorophosphate, borate, oxalate and fluorosulfonate can be 0.01% by weight or more, preferably 0.1% by weight. % or more and can be 20% by mass or less, preferably 10% by mass or less.

The electrolyte preferably contains one or more selected from the group consisting of monofluorophosphate, difluorophosphate, borate, oxalate, and fluorosulfonate, and one or more other salts. . Examples of other salts include the lithium salts listed above, particularly LiPF ₆ , LiN(FSO ₂ )(CF ₃ SO ₂ ), LiN(CF ₃ SO ₂ ) ₂ , L
iN(C ₂ F ₅ SO ₂ ) ₂ , lithium cyclic 1,2-perfluoroethanedisulfonylimide, lithium cyclic 1,3-perfluoropropanedisulfonylimide, LiC(FSO ₂
) ₃ , LiC(CF ₃ SO ₂ ) ₃ , LiC(C ₂ F ₅ SO ₂ ) ₃ , LiBF ₃ CF ₃ , L
iBF ₃ C ₂ F ₅ , LiPF ₃ (CF ₃ ) ₃ and LiPF ₃ (C ₂ F ₅ ) ₃ are preferred, and L
iPF ₆ is even more preferred. The other salts can be 0.01% by mass or more, preferably 0.1% by mass or more, and 20% by mass from the viewpoint of ensuring an appropriate balance between the conductivity and viscosity of the electrolytic solution. It can be at most 15% by mass, preferably at most 10% by mass.

1-3-1. Monofluorophosphate, difluorophosphate The monofluorophosphate and difluorophosphate according to the present invention are salts having at least one monofluorophosphate or difluorophosphate structure in the molecule, respectively; There are no particular restrictions. In the electrolyte solution of the present invention, by using the compound represented by the above formula (1) or formula (2) together with one or more selected from monofluorophosphates and difluorophosphates, this electrolyte solution can be used. The durability of the battery can be improved.

Counter cations in monofluorophosphate and difluorophosphate are not particularly limited, and include lithium, sodium, potassium, magnesium, calcium, NR ¹²¹ R
Examples include ammonium represented by ¹²² R ¹²³ R ¹²⁴ (wherein R ¹²¹ to R ¹²⁴ are independently a hydrogen atom or an organic group having 1 to 12 carbon atoms). The organic group having 1 to 12 carbon atoms represented by R ¹²¹ to R ¹²⁴ of the above ammonium is not particularly limited, and may be substituted with an alkyl group optionally substituted with a fluorine atom, a halogen atom, or an alkyl group. Examples include a cycloalkyl group which may be substituted with a halogen atom or an alkyl group, a nitrogen atom-containing heterocyclic group which may have a substituent.
Among these, R ¹²¹ to R ¹²⁴ are preferably independently a hydrogen atom, an alkyl group, a cycloalkyl group, a nitrogen atom-containing heterocyclic group, or the like. As the counter cation, lithium, sodium, and potassium are preferable, and lithium is especially preferable.

Examples of the monofluorophosphate and difluorophosphate include lithium monofluorophosphate, sodium monofluorophosphate, potassium monofluorophosphate, lithium difluorophosphate, sodium difluorophosphate, potassium difluorophosphate, etc. Lithium monofluorophosphate and lithium difluorophosphate are preferred, and lithium difluorophosphate is more preferred. One type of monofluorophosphate and difluorophosphate may be used alone, or two or more types may be used in combination in any combination and ratio.

The amount of one or more selected from monofluorophosphate and difluorophosphate (total amount if two or more) is usually 0.001% by mass or more, preferably 0.01% by mass or more,
More preferably 0.1% by mass or more, still more preferably 0.2% by mass or more, particularly preferably 0
．． 3% by mass or more, and usually 5% by mass or less, preferably 3% by mass or less, more preferably 2% by mass or less, even more preferably 1.5% by mass or less, particularly preferably 1% by mass or less. be. Within this range, the effect of improving the initial irreversible capacity is significantly exhibited.

1-3-2. Borate The borate according to the present invention is not particularly limited as long as it has at least one boron atom in the molecule. However, those that fall under oxalates are listed in 1-3-2. Not borate, but 1-3-3 described below. shall be included in oxalates. By using the compound represented by formula (1) or formula (2) in combination with a borate in the electrolytic solution of the present invention, the durability characteristics of a battery using this electrolytic solution can be improved.

Examples of the counter cation in the borate include lithium, sodium, potassium, magnesium, calcium, rubidium, cesium, barium, and the like, with lithium being preferred.
As the borate, lithium salts are preferred, and borate-containing lithium salts can also be suitably used. For example, LiBF ₄ , LiBF ₃ CF ₃ , LiBF ₃ C ₂ F ₅ , LiBF ₃ C ₃
F ₇ , LiBF ₂ (CF ₃ ) ₂ , LiBF ₂ (C ₂ F ₅ ) ₂ , LiBF ₂ (CF ₃ SO ₂
) ₂ , LiBF ₂ (C ₂ F ₅ SO ₂ ) ₂ , and the like. Among these, LiBF ₄ is more preferable since it has the effect of improving initial charge/discharge efficiency, high temperature cycle characteristics, and the like. The borate is
One type may be used alone, or two or more types may be used in combination in any combination and ratio.

The amount of borates (total amount in the case of two or more types) is usually 0.05% by mass or more, preferably 0.1% by mass or more, more preferably 0.2% by mass or more, even more preferably 0. .3% by mass
Above, it is particularly preferably 0.4% by mass or more, and usually 10.0% by mass or less,
Preferably 5.0% by mass or less, more preferably 3.0% by mass or less, even more preferably 2.0% by mass
It is preferably at most 1.0% by mass, particularly preferably at most 1.0% by mass. Within this range, side reactions at the battery negative electrode are suppressed, making it difficult to increase resistance.

1-3-3. Oxalate The oxalate according to the present invention is not particularly limited as long as it is a compound having at least one oxalic acid structure in the molecule. By using the compound represented by formula (1) or formula (2) and oxalate together in the electrolytic solution of the present invention, the durability characteristics of a battery using this electrolytic solution can be improved.
As the oxalate, a metal salt represented by the following formula (9) is preferable. This salt is a salt having an oxalato complex as an anion.

(In the formula, M ¹ is an element selected from the group consisting of Group 1, Group 2 and aluminum (Al) in the periodic table, and M ² is a transition metal, selected from the group consisting of Groups 13, 14 and 15 of the periodic table. ^R91 is a group selected from the group consisting of halogen, an alkyl group having 1 to 11 carbon atoms, and a halogen-substituted alkyl group having 1 to 11 carbon atoms, and a and b are is a positive integer, c is 0 or a positive integer, and d is an integer from 1 to 3.)
From the viewpoint of battery characteristics when the electrolytic solution of the present invention is used in a lithium secondary battery, M ¹ is preferably lithium, sodium, potassium, magnesium, or calcium, and particularly preferably lithium.

M ² is particularly preferably boron or phosphorus in terms of electrochemical stability when used in a lithium secondary battery.
^R91 is fluorine, chlorine, methyl group, trifluoromethyl group, ethyl group, pentafluoroethyl group, propyl group, isopropyl group, butyl group, sec-butyl group, ter
Examples include t-butyl group, and fluorine and trifluoromethyl groups are preferred.

Examples of the metal salt represented by formula (9) include the following.
Lithium oxalatoborate salts such as lithium difluorooxalatoborate and lithium bis(oxalato)borate;
Lithium oxalatophosphate salts such as lithium tetrafluorooxalatophosphate, lithium difluorobis(oxalato)phosphate, lithium tris(oxalato)phosphate;
Among these, lithium bis(oxalato)borate and lithium difluorobis(oxalato)phosphate are preferred, and lithium bis(oxalato)borate is more preferred.

One type of oxalate may be used alone, or two or more types may be used in combination in any combination and ratio.
The amount of oxalate (total amount in case of two or more types) is usually 0.001% by mass or more, preferably 0.01% by mass or more, more preferably 0.1% by mass or more, particularly preferably 0. .3
It is at least 10% by mass, preferably at most 5% by mass, more preferably at most 3% by mass, even more preferably at most 2% by mass, particularly preferably at most 1% by mass. Within this range, it is easy to control output characteristics, load characteristics, low temperature characteristics, cycle characteristics, high temperature storage characteristics, etc.

1-3-4. Fluorosulfonate The fluorosulfonate according to the present invention is not particularly limited as long as it has at least one fluorosulfonic acid structure in the molecule. In the electrolytic solution of the present invention, by using the compound represented by the above formula (1) or formula (2) together with a fluorosulfonate, the durability characteristics of a battery using this electrolytic solution can be improved. .

Counter cations in the fluorosulfonate are not particularly limited, and include lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, barium, and NR ¹³¹ R ¹³² R ¹³³ R ¹³⁴ (wherein R ¹³¹ to R ¹³⁴ are Examples include ammonium, each independently represented by a hydrogen atom or an organic group having 1 or more and 12 or less carbon atoms. The organic group having 1 to 12 carbon atoms represented by R ¹³¹ to R ¹³⁴ of the above ammonium is not particularly limited, and may be substituted with an alkyl group optionally substituted with a fluorine atom, a halogen atom, or an alkyl group. Examples thereof include a cycloalkyl group that may be substituted with a halogen atom or an alkyl group, an aryl group that may be substituted with a halogen atom or an alkyl group, and a nitrogen-containing heterocyclic group that may have a substituent. Among these, R ¹³¹ to R ¹³⁴ are preferably independently a hydrogen atom, an alkyl group, a cycloalkyl group, a nitrogen atom-containing heterocyclic group, or the like. As the counter cation, lithium, sodium, and potassium are preferable, and lithium is especially preferable.

Examples of the fluorosulfonate include lithium fluorosulfonate, sodium fluorosulfonate, potassium fluorosulfonate, rubidium fluorosulfonate, cesium fluorosulfonate, and the like, with lithium fluorosulfonate being preferred. Lithium bis(
An imide salt having a fluorosulfonic acid structure such as fluorosulfonyl)imide can also be used as the fluorosulfonate.

One type of fluorosulfonate may be used alone, or two or more types may be used in combination in any combination and ratio.
The content of fluorosulfonic acid salts (total amount in the case of two or more types) is usually 0.05% by mass or more, preferably 0.1% by mass or more, more preferably 0.2% by mass or more, even more preferably is 0.3% by mass or more, particularly preferably 0.4% by mass or more, and usually 10% by mass
or less, preferably 8% by mass or less, more preferably 5% by mass or less, even more preferably 2% by mass or less.
It is not more than 1% by mass, particularly preferably not more than 1% by mass. Within this range, there are few side reactions in the battery and it is difficult to increase the resistance.

1-4. Nonaqueous Solvent There are no particular limitations on the nonaqueous solvent in the present invention, and any known organic solvent can be used. Specifically, cyclic carbonates (excluding fluorine-containing cyclic carbonates).
), chain carbonates, cyclic and chain carboxylic acid esters, ether compounds, sulfone compounds, and the like.
Further, in this specification, the volume of a nonaqueous solvent is a value measured at 25°C, but for a substance that is solid at 25°C, such as ethylene carbonate, a value measured at the melting point is used.

1-4-1. Cyclic carbonates (excluding fluorine-containing cyclic carbonates)
The cyclic carbonate according to the present invention includes a cyclic carbonate having an alkylene group having 2 to 4 carbon atoms.
Specific examples of cyclic carbonates having an alkylene group having 2 to 4 carbon atoms include ethylene carbonate, propylene carbonate, and butylene carbonate. Among these, ethylene carbonate and propylene carbonate are particularly preferable from the viewpoint of improving battery characteristics due to improved degree of lithium ion dissociation.
One type of cyclic carbonate may be used alone, or two or more types may be used in combination in any combination and ratio.

The amount of the cyclic carbonate to be blended is not particularly limited and may be arbitrary as long as it does not significantly impair the effects of the present invention, but when one type is used alone, the amount to be blended is 5% by volume in 100% by volume of the non-aqueous solvent.
The content is more preferably 10% by volume or more. By setting this range, it is possible to avoid a decrease in electrical conductivity due to a decrease in the dielectric constant of the non-aqueous electrolyte, and it is easier to maintain the large current discharge characteristics, stability against the negative electrode, and cycle characteristics of the energy device within a favorable range. . Moreover, it is 95 volume% or less, more preferably 90 volume% or less, and even more preferably 85 volume% or less. By setting it within this range, the viscosity of the non-aqueous electrolyte can be set in an appropriate range, a decrease in ionic conductivity can be suppressed, and the load characteristics of the energy device can be easily set in a good range.

1-4-2. Chain Carbonate The chain carbonate according to the present invention is preferably a chain carbonate having 3 to 7 carbon atoms, and more preferably a dialkyl carbonate having 3 to 7 carbon atoms.
Examples of chain carbonates include dimethyl carbonate, diethyl carbonate, di-n-
Propyl carbonate, diisopropyl carbonate, n-propyl isopropyl carbonate, ethyl methyl carbonate, methyl-n-propyl carbonate, n-butyl methyl carbonate, isobutyl methyl carbonate, tert-butyl methyl carbonate, ethyl-n-propyl carbonate, n-butylethyl carbonate, isobutylethyl carbonate, tert-butylethyl carbonate and the like.

Among them, dimethyl carbonate, diethyl carbonate, di-n-propyl carbonate, diisopropyl carbonate, n-propylisopropyl carbonate, ethylmethyl carbonate, and methyl-n-propyl carbonate are preferred, and dimethyl carbonate, diethyl carbonate, and ethylmethyl carbonate are particularly preferred. be.
In addition, chain carbonates having a fluorine atom (hereinafter referred to as "fluorinated chain carbonates")
) can also be suitably used.

The number of fluorine atoms that the fluorinated chain carbonate has is not particularly limited as long as it is 1 or more, but it is usually 6 or less, preferably 4 or less. When the fluorinated chain carbonate has a plurality of fluorine atoms, they may be bonded to the same carbon or different carbons.
As the fluorinated chain carbonate, fluorinated dimethyl carbonate and its derivatives,
Examples include fluorinated ethyl methyl carbonate and its derivatives, fluorinated diethyl carbonate and its derivatives, and the like.

Examples of fluorinated dimethyl carbonate and its derivatives include fluoromethylmethyl carbonate, difluoromethylmethyl carbonate, trifluoromethylmethyl carbonate, bis(fluoromethyl) carbonate, bis(difluoro)methyl carbonate, bis(trifluoromethyl) carbonate, etc. It will be done.
Examples of fluorinated ethylmethyl carbonate and its derivatives include 2-fluoroethylmethyl carbonate, ethylfluoromethyl carbonate, 2,2-difluoroethylmethyl carbonate, 2-fluoroethylfluoromethyl carbonate, ethyl difluoromethyl carbonate, 2,2,2 -trifluoroethylmethyl carbonate, 2,2-difluoroethylfluoromethyl carbonate, 2-fluoroethyldifluoromethyl carbonate, ethyltrifluoromethyl carbonate and the like.

Examples of fluorinated diethyl carbonate and its derivatives include ethyl-(2-fluoroethyl) carbonate, ethyl-(2,2-difluoroethyl) carbonate, bis(2-fluoroethyl) carbonate, ethyl-(2,2,2- trifluoroethyl) carbonate, 2,2-difluoroethyl-2'-fluoroethyl carbonate, bis(2,2-difluoroethyl) carbonate, 2,2,2-trifluoroethyl-2'-fluoroethyl carbonate, 2, Examples include 2,2-trifluoroethyl-2',2'-difluoroethyl carbonate and bis(2,2,2-trifluoroethyl) carbonate.

One type of chain carbonate may be used alone, or two or more types may be used in combination in any combination and ratio. The blending amount of the chain carbonate is preferably 5% by volume or more, more preferably 10% by volume or more, still more preferably 15% by volume or more in 100% by volume of the nonaqueous solvent. By setting the lower limit in this manner, the viscosity of the non-aqueous electrolyte can be set in an appropriate range, a decrease in ionic conductivity can be suppressed, and the large current discharge characteristics of the energy device can be easily set in a good range. Moreover, it is preferable that the linear carbonate is 90 volume % or less, more preferably 85 volume % or less in 100 volume % of the nonaqueous solvent. By setting the upper limit in this way, it is possible to avoid a decrease in electrical conductivity due to a decrease in the dielectric constant of the non-aqueous electrolyte, and it becomes easier to maintain the large current discharge characteristics of the energy device within a favorable range.

1-4-3. Cyclic and Chain Carboxylic Acid Ester The cyclic carboxylic acid ester according to the present invention preferably has 3 to 12 carbon atoms.
Specifically, gamma butyrolactone, gamma valerolactone, gamma macaprolactone,
Examples include epsilon caprolactone. Among these, gamma-butyrolactone is particularly preferable from the viewpoint of improving battery characteristics due to an improvement in the degree of lithium ion dissociation.

One type of cyclic carboxylic acid ester may be used alone, or two or more types may be used in combination in any combination and ratio.
The amount of the cyclic carboxylic acid ester is usually preferably 5% by volume or more, more preferably 10% by volume or more, based on 100% by volume of the nonaqueous solvent. Within this range, the electrical conductivity of the non-aqueous electrolyte can be improved and the large current discharge characteristics of the energy device can be easily improved. Also,
The content of the cyclic carboxylic acid ester is preferably 50% by volume or less, more preferably 40% by volume or less. By setting the upper limit in this way, the viscosity of the non-aqueous electrolyte can be kept within an appropriate range, a decrease in electrical conductivity can be avoided, an increase in negative electrode resistance can be suppressed, and the large current discharge characteristics of energy devices can be maintained within a good range. It becomes easier to

Examples of chain carboxylic esters include those shown in "1-1-1. Carboxylic esters".
When the chain carboxylic acid ester is used as a non-aqueous solvent, the blending amount is preferably 1% by volume or more, more preferably 5% by volume or more, still more preferably 10% by volume or more, and even more preferably in 100% by volume of the non-aqueous solvent. It is preferably contained in an amount of 20 vol% or more, and can be contained in an amount of 50 vol% or less, more preferably 45 vol% or less, still more preferably 40 vol% or less. When the content of the chain carboxylic acid ester is within the above range, the electrical conductivity of the nonaqueous electrolyte is improved, and the input/output characteristics and charge/discharge rate characteristics of the nonaqueous electrolyte secondary battery are easily improved. Also,
This suppresses the increase in negative electrode resistance and makes it easier to maintain the input/output characteristics and charge/discharge rate characteristics of the nonaqueous electrolyte secondary battery within a favorable range.

In addition, when a chain carboxylic acid ester is used as a non-aqueous solvent, it is preferably used in combination with a cyclic carbonate, and more preferably a combination of a cyclic carbonate and a chain carbonate.
For example, when a cyclic carbonate and a chain carboxylic acid ester are used together, the content of the cyclic carbonate is not particularly limited and may be arbitrary as long as it does not significantly impair the effects of the present invention, but it is usually 15% by volume or more, preferably 20% by volume or more. The content of the chain carboxylic acid ester is usually 20 volume% or more, preferably 30 volume% or more, and usually 55 volume% or less, preferably 45 volume% or less, preferably 40 volume% or less. is 50% by volume or less. In addition, when a cyclic carbonate, a chain carbonate, and a chain carboxylic acid ester are used together, the content of the cyclic carbonate is not particularly limited, and is arbitrary as long as it does not significantly impair the effects of the present invention, but it is usually 15% by volume or more. , preferably 20 volume %, and usually 45 volume % or less, preferably 40 volume % or less, and the content of chain carbonate is usually 25 volume % or more, preferably 30 volume % or more, and usually 84 volume % or less. , preferably 80% by volume or less. By keeping the content within the above range, it is possible to lower the low-temperature precipitation temperature of the electrolyte, while also lowering the viscosity of the non-aqueous electrolyte and improving the ionic conductivity, making it possible to obtain higher input and output even at low temperatures. It is also preferable from the viewpoint of further reducing battery swelling.

1-4-4. Ether Compound The ether compound according to the present invention is preferably a chain ether having 3 to 10 carbon atoms and a cyclic ether having 3 to 6 carbon atoms, in which some of the hydrogens may be replaced with fluorine.
As a chain ether having 3 to 10 carbon atoms,
Diethyl ether, di(2-fluoroethyl)ether, di(2,2-difluoroethyl)ether, di(2,2,2-trifluoroethyl)ether, ethyl(2-fluoroethyl)ether, ethyl(2, 2,2-trifluoroethyl)ether, ethyl (1,
1,2,2-tetrafluoroethyl)ether, (2-fluoroethyl)(2,2,2-
(trifluoroethyl) ether, (2-fluoroethyl)(1,1,2,2-tetrafluoroethyl)ether, (2,2,2-trifluoroethyl)(1,1,2,2-tetrafluoroethyl) ) ether, ethyl-n-propyl ether, ethyl (3-fluoro-n
-propyl) ether, ethyl (3,3,3-trifluoro-n-propyl) ether,
Ethyl (2,2,3,3-tetrafluoro-n-propyl)ether, ethyl (2,2,
3,3,3-pentafluoro-n-propyl) ether, 2-fluoroethyl-n-propyl ether, (2-fluoroethyl)(3-fluoro-n-propyl)ether, (2
-fluoroethyl)(3,3,3-trifluoro-n-propyl)ether, (2-fluoroethyl)(2,2,3,3-tetrafluoro-n-propyl)ether, (2-fluoroethyl) (2,2,3,3,3-pentafluoro-n-propyl)ether, 2,2
, 2-trifluoroethyl-n-propyl ether, (2,2,2-trifluoroethyl)(3-fluoro-n-propyl)ether, (2,2,2-trifluoroethyl)(3
, 3,3-trifluoro-n-propyl)ether, (2,2,2-trifluoroethyl)(2,2,3,3-tetrafluoro-n-propyl)ether, (2,2,2- trifluoroethyl)(2,2,3,3,3-pentafluoro-n-propyl)ether, 1,
1,2,2-tetrafluoroethyl-n-propyl ether, (1,1,2,2-tetrafluoroethyl)(3-fluoro-n-propyl)ether, (1,1,2,2-tetrafluoro ethyl)(3,3,3-trifluoro-n-propyl)ether, (1,1,2
,2-tetrafluoroethyl)(2,2,3,3-tetrafluoro-n-propyl)ether,(1,1,2,2-tetrafluoroethyl)(2,2,3,3,3-penta fluoro-n-propyl) ether, di-n-propyl ether, (n-propyl)(3-fluoro-n-propyl)ether, (n-propyl)(3,3,3-trifluoro-n-propyl) Ether, (n-propyl)(2,2,3,3-tetrafluoro-n-propyl)ether, (n-propyl)(2,2,3,3,3-pentafluoro-n-propyl)
Ether, di(3-fluoro-n-propyl) ether, (3-fluoro-n-propyl)(3,3,3-trifluoro-n-propyl)ether, (3-fluoro-n-propyl)(2 , 2,3,3-tetrafluoro-n-propyl)ether, (3-fluoro-n
-propyl)(2,2,3,3,3-pentafluoro-n-propyl)ether, di(3
, 3,3-trifluoro-n-propyl)ether, (3,3,3-trifluoro-n-
propyl)(2,2,3,3-tetrafluoro-n-propyl)ether, (3,3,3
-trifluoro-n-propyl)(2,2,3,3,3-pentafluoro-n-propyl)ether, di(2,2,3,3-tetrafluoro-n-propyl)ether, (2, 2
,3,3-tetrafluoro-n-propyl)(2,2,3,3,3-pentafluoro-n
-propyl) ether, di(2,2,3,3,3-pentafluoro-n-propyl) ether, di-n-butyl ether, dimethoxymethane, methoxyethoxymethane, methoxy(2-fluoroethoxy)methane, methoxy( 2,2,2-trifluoroethoxy)methane Methoxy(1,1,2,2-tetrafluoroethoxy)methane, diethoxymethane, ethoxy(2-fluoroethoxy)methane, ethoxy(2,2,2-trifluoroethoxy)methane ethoxy)methane, ethoxy(1,1,2,2-tetrafluoroethoxy)methane, di(2-fluoroethoxy)methane, (2-fluoroethoxy)(2,2,2-trifluoroethoxy)methane, (2 -fluoroethoxy)(1,1,2,2-tetrafluoroethoxy)methanedi(2,2,2-trifluoroethoxy)methane,(2,2,2-trifluoroethoxy)(1,1,2,2 -tetrafluoroethoxy)methane, di(1,1,2,2-tetrafluoroethoxy)methane, dimethoxyethane, methoxyethoxyethane, methoxy(2
-fluoroethoxy)ethane, methoxy(2,2,2-trifluoroethoxy)ethane,
Methoxy(1,1,2,2-tetrafluoroethoxy)ethane, diethoxyethane, ethoxy(2-fluoroethoxy)ethane, ethoxy(2,2,2-trifluoroethoxy)
Ethane, ethoxy(1,1,2,2-tetrafluoroethoxy)ethane, di(2-fluoroethoxy)ethane, (2-fluoroethoxy)(2,2,2-trifluoroethoxy)
Ethane, (2-fluoroethoxy)(1,1,2,2-tetrafluoroethoxy)ethane, di(2,2,2-trifluoroethoxy)ethane, (2,2,2-trifluoroethoxy)(1 , 1,2,2-tetrafluoroethoxy)ethane, di(1,1,2,2-tetrafluoroethoxy)ethane, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, diethylene glycol dimethyl ether, etc. Can be mentioned.

Examples of the cyclic ether having 3 to 6 carbon atoms include tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, 1,4-dioxane, and fluorinated compounds thereof.
Among them, dimethoxymethane, diethoxymethane, ethoxymethoxymethane, ethylene glycol di-n-propyl ether, ethylene glycol di-n-butyl ether, and diethylene glycol dimethyl ether have a high ability to solvate lithium ions and improve ion dissociation properties. Dimethoxymethane, diethoxymethane, and ethoxymethoxymethane are particularly preferred because they have low viscosity and high ionic conductivity.

The ether compounds may be used alone or in combination of two or more in any desired ratio.
The amount of the ether compound is usually preferably 5% by volume or more, more preferably 10% by volume or more, even more preferably 15% by volume or more, and preferably 70% by volume or less, based on 100% by volume of the nonaqueous solvent. The content is more preferably 60% by volume or less, and still more preferably 50% by volume or less. Within this range, it is easy to ensure the effect of improving the ionic conductivity due to the improvement in the dissociation degree of lithium ions and the decrease in viscosity of the chain ether, and when the negative electrode active material is a carbonaceous material, the chain ether together with the lithium ions can be easily secured. It is easy to avoid a situation where the capacity decreases due to co-insertion.

1-4-5. Sulfone compound The sulfone compound according to the present invention includes a cyclic sulfone having 3 to 6 carbon atoms, and a cyclic sulfone having 2 to 6 carbon atoms.
~6 chain sulfones are preferred. The number of sulfonyl groups in one molecule is preferably 1 or 2.
Examples of cyclic sulfones having 3 to 6 carbon atoms include monosulfone compounds such as trimethylene sulfones, tetramethylene sulfones, and hexamethylene sulfones;
Examples include disulfone compounds such as trimethylene disulfones, tetramethylene disulfones, and hexamethylene disulfones.

Among them, from the viewpoint of dielectric constant and viscosity, tetramethylene sulfones, tetramethylene disulfones, hexamethylene sulfones, and hexamethylene disulfones are more preferable, and tetramethylene sulfones (sulfolanes) are particularly preferable.
As the sulfolanes, sulfolanes and/or sulfolane derivatives (hereinafter, sulfolanes may also be referred to as "sulfolanes") are preferred. As the sulfolane derivative, one in which one or more of the hydrogen atoms bonded to the carbon atoms constituting the sulfolane ring is substituted with a fluorine atom or an alkyl group is preferable.

Among them, 2-methylsulfolane, 3-methylsulfolane, 2-fluorosulfolane, 3
-Fluorosulfolane, 2,2-difluorosulfolane, 2,3-difluorosulfolane, 2,4-difluorosulfolane, 2,5-difluorosulfolane, 3,4-difluorosulfolane, 2-fluoro-3-methylsulfolane, 2- Fluoro-2-methylsulfolane, 3-fluoro-3-methylsulfolane, 3-fluoro-2-methylsulfolane, 4-
Fluoro-3-methylsulfolane, 4-fluoro-2-methylsulfolane, 5-fluoro-3-methylsulfolane, 5-fluoro-2-methylsulfolane, 2-fluoromethylsulfolane, 3-fluoromethylsulfolane, 2-difluoromethyl Sulfolane, 3-difluoromethylsulfolane, 2-trifluoromethylsulfolane, 3-trifluoromethylsulfolane, 2-fluoro-3-(trifluoromethyl)sulfolane, 3-fluoro-3
-(trifluoromethyl)sulfolane, 4-fluoro-3-(trifluoromethyl)sulfolane, 5-fluoro-3-(trifluoromethyl)sulfolane, etc. are preferred in terms of high ionic conductivity and high input/output characteristics. .

In addition, as a chain sulfone having 2 to 6 carbon atoms,
Dimethylsulfone, ethylmethylsulfone, diethylsulfone, n-propylmethylsulfone, n-propylethylsulfone, di-n-propylsulfone, isopropylmethylsulfone, isopropylethylsulfone, diisopropylsulfone, n-butylmethylsulfone, n-butylethyl Sulfone, tert-butylmethylsulfone, tert-butylethylsulfone, monofluoromethylmethylsulfone, difluoromethylmethylsulfone, trifluoromethylmethylsulfone, monofluoroethylmethylsulfone, difluoroethylmethylsulfone, trifluoroethylmethylsulfone, pentafluoro Ethyl methyl sulfone, ethyl monofluoromethyl sulfone, ethyl difluoromethyl sulfone,
Ethyltrifluoromethylsulfone, perfluoroethylmethylsulfone, ethyltrifluoroethylsulfone, ethylpentafluoroethylsulfone, di(trifluoroethyl)sulfone, perfluorodiethylsulfone, fluoromethyl-n-propylsulfone,
Difluoromethyl-n-propylsulfone, trifluoromethyl-n-propylsulfone, fluoromethylisopropylsulfone, difluoromethylisopropylsulfone, trifluoromethylisopropylsulfone, trifluoroethyl-n-propylsulfone, trifluoroethylisopropylsulfone, pentafluoro Ethyl-n-propylsulfone, pentafluoroethylisopropylsulfone, trifluoroethyl-n-butylsulfone, trifluoroethyl-tert-butylsulfone, pentafluoroethyl-n-butylsulfone, pentafluoroethyl-tert-butylsulfone, etc. Can be mentioned.

Among them, dimethylsulfone, ethylmethylsulfone, diethylsulfone, n-propylmethylsulfone, isopropylmethylsulfone, n-butylmethylsulfone, tert-
Butyl methyl sulfone, monofluoromethyl methyl sulfone, difluoromethyl methyl sulfone, trifluoromethyl methyl sulfone, monofluoroethyl methyl sulfone, difluoroethyl methyl sulfone, trifluoroethyl methyl sulfone, pentafluoroethyl methyl sulfone, ethyl monofluoromethyl sulfone, Ethyldifluoromethylsulfone, ethyltrifluoromethylsulfone, ethyltrifluoroethylsulfone, ethylpentafluoroethylsulfone, trifluoromethyl-n-propylsulfone, trifluoromethylisopropylsulfone, trifluoroethyl-n-butylsulfone, trifluoroethyl -tert-butylsulfone, trifluoromethyl-n-butylsulfone, trifluoromethyl-tert-butylsulfone and the like are preferred because they have high ionic conductivity and high input/output characteristics.

One type of sulfone compound may be used alone, or two or more types may be used in combination in any combination and ratio.
The amount of the sulfone compound is usually preferably 0.3% by volume or more, more preferably 1% by volume or more, still more preferably 5% by volume or more, and preferably 40% by volume or more, based on 100% by volume of the nonaqueous solvent. It is less than 35% by volume, more preferably less than 30% by volume, even more preferably less than 30% by volume. Within this range, it is easy to obtain the effect of improving durability such as cycle characteristics and storage characteristics, and it is also possible to keep the viscosity of the non-aqueous electrolyte within an appropriate range and avoid a decrease in electrical conductivity. When charging and discharging a device at a high current density, it is easy to avoid a situation where the charge/discharge capacity retention rate decreases.

1-4-6. Composition of Nonaqueous Solvent As the nonaqueous solvent of the present invention, one type of nonaqueous solvent exemplified above may be used alone, or two or more types may be used in combination in any combination and ratio.
For example, one preferred combination of nonaqueous solvents is a combination mainly consisting of a cyclic carbonate (excluding fluorine-containing cyclic carbonates) and a chain carbonate.

Among them, the total of the cyclic carbonate and the chain carbonate in the nonaqueous solvent is preferably 70% by volume or more, more preferably 80% by volume or more, and still more preferably 90% by volume or more, and the cyclic carbonate and the chain carbonate The ratio of cyclic carbonate to the total of
The content is preferably 50% by volume or less, more preferably 35% by volume or less, still more preferably 30% by volume or less, particularly preferably 25% by volume or less.

When a combination of these non-aqueous solvents is used, the cycle characteristics and high-temperature storage characteristics (particularly the residual capacity after high-temperature storage and high-load discharge capacity) of a battery manufactured using the same may be better balanced.
For example, a preferable combination of a cyclic carbonate and a chain carbonate is:
Ethylene carbonate and dimethyl carbonate, ethylene carbonate and diethyl carbonate, ethylene carbonate and ethyl methyl carbonate, ethylene carbonate and dimethyl carbonate and diethyl carbonate, ethylene carbonate and dimethyl carbonate and ethyl methyl carbonate, ethylene carbonate and diethyl carbonate and ethyl methyl carbonate, ethylene carbonate and dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate.

Among the combinations of a cyclic carbonate and a chain carbonate, those containing an asymmetric chain alkyl carbonate as the chain carbonate are more preferable, and in particular, ethylene carbonate, dimethyl carbonate and ethyl methyl carbonate, ethylene carbonate, diethyl carbonate and ethyl Those containing ethylene carbonate, symmetrical chain carbonates, and asymmetric chain carbonates such as methyl carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, and ethylmethyl carbonate are preferred because they have a good balance between cycle characteristics and large current discharge characteristics.

Among these, the asymmetric chain carbonate is preferably ethyl methyl carbonate, and the alkyl group of the chain carbonate preferably has 1 to 2 carbon atoms.
Combinations in which propylene carbonate is further added to these combinations of ethylene carbonate and chain carbonates are also cited as preferred combinations.
When containing propylene carbonate, the volume ratio of ethylene carbonate to propylene carbonate is preferably 99:1 to 40:60, particularly preferably 95:5 to 50.
:50. Further, the proportion of propylene carbonate in the entire non-aqueous solvent is preferably 0.1% by volume or more, more preferably 1% by volume or more, even more preferably 2% by volume or more, and more preferably 20% by volume or less, more preferably is 8% by volume or less, more preferably 5% by volume or less.

Containing propylene carbonate in this concentration range is preferable because it may provide even better low-temperature properties while maintaining the properties of the combination of ethylene carbonate and chain carbonate.
When dimethyl carbonate is contained in the nonaqueous solvent, the proportion of dimethyl carbonate in the total nonaqueous solvent is preferably 10% by volume or more, more preferably 20% by volume or more, still more preferably 25% by volume or more, especially The content is preferably 30% by volume or more, and preferably 90% by volume or less, more preferably 80% by volume or less, even more preferably 75% by volume or less, particularly preferably 70% by volume or less, The load characteristics of the battery may be improved.

Among these, it contains dimethyl carbonate and ethyl methyl carbonate, and by making the content of dimethyl carbonate higher than the content of ethyl methyl carbonate, it is possible to maintain the electrical conductivity of the electrolyte while improving the battery characteristics after high-temperature storage. This is preferable because it can improve the
The volume ratio of dimethyl carbonate to ethyl methyl carbonate in the total nonaqueous solvent (dimethyl carbonate/ethyl methyl carbonate) is 1.1 or more in terms of improving the electrical conductivity of the electrolyte and improving the battery characteristics after storage. is preferable, 1.5 or more is more preferable, and 2.5 or more is still more preferable. The volume ratio (dimethyl carbonate/ethyl methyl carbonate) is preferably 40 or less, more preferably 20 or less, even more preferably 10 or less, particularly preferably 8 or less, from the viewpoint of improving battery characteristics at low temperatures.

In combinations mainly consisting of the above cyclic carbonates (excluding fluorine-containing cyclic carbonates) and chain carbonates, cyclic carboxylic acid esters, chain carboxylic acid esters, cyclic ethers, chain ethers, sulfur-containing Other solvents such as organic solvents, phosphorus-containing organic solvents, aromatic fluorine-containing solvents, etc. may be mixed.

1-5. Auxiliary Agent In the non-aqueous electrolytic solution of the present invention, in addition to the above-mentioned compounds, an appropriate auxiliary agent may be used depending on the purpose. Examples of the auxiliary agent include other auxiliary agents shown below.

1-5-1. Other Auxiliary Agents Other known auxiliary agents can be used in the non-aqueous electrolyte of the present invention. Other auxiliary agents include carbonate compounds such as erythritan carbonate, spiro-bis-dimethylene carbonate, methoxyethyl-methyl carbonate; succinic anhydride, glutaric anhydride, maleic anhydride, citraconic anhydride, glutaconic anhydride, Carboxylic acid anhydrides such as itaconic acid, diglycolic anhydride, cyclohexanedicarboxylic anhydride, cyclopentanetetracarboxylic dianhydride, and phenylsuccinic anhydride; 3,9-divinyl-2,4,8,
Spiro compounds such as 10-tetraoxaspiro[5.5]undecane; Sulfur-containing compounds such as N,N-dimethylmethanesulfonamide, N,N-diethylmethanesulfonamide; Trimethyl phosphite, triethyl phosphite, Phosphorous compounds such as triphenyl phosphate, trimethyl phosphate, triethyl phosphate, triphenyl phosphate, methyl dimethylphosphinate, ethyl diethylphosphinate, trimethylphosphine oxide, triethylphosphine oxide; 1-methyl-2-pyrrolidinone, 1 - Nitrogen-containing compounds such as methyl-2-piperidone, 3-methyl-2-oxazolidinone, 1,3-dimethyl-2-imidazolidinone and N-methylsuccinimide; carbonization of heptane, octane, nonane, decane, cycloheptane, etc. Hydrogen compound; 2-propynyl 2-(diethoxyphosphoryl)acetate, 1-methyl-2-
Propynyl 2-(diethoxyphosphoryl)acetate, 1,1-dimethyl-2-propynyl 2-(diethoxyphosphoryl)acetate, pentafluorophenyl methanesulfonate, pentafluorophenyl trifluoromethanesulfonate, pentafluorophenyl acetate, pentafluoroacetate Fluorophenyl, methylpentafluorophenyl carbonate, 2-propynyl 2-(methanesulfonyloxy)propionate, 2-methyl 2-(methanesulfonyloxy)propionate, 2-ethyl 2-(methanesulfonyloxy)propionate, methanesulfonyl 2-propynyl oxyacetate, 2-methyl methanesulfonyloxyacetate, 2-ethyl methanesulfonyloxyacetate, lithium ethyl methyloxycarbonylphosphonate, lithium ethyl ethyloxycarbonylphosphonate, lithium ethyl 2-propynyloxycarbonylphosphonate, lithium ethyl 1-methyl -2-Propynyloxycarbonylphosphonate, lithium ethyl 1
, 1-dimethyl-2-propynyloxycarbonylphosphonate, lithium methyl sulfate, lithium ethyl sulfate, lithium 2-propynyl sulfate, lithium 1-methyl-2-propynyl sulfate, lithium 1,1-dimethyl-2-propynyl sulfate, lithium 2 ,2,2-trifluoroethyl sulfate, methyl trimethylsilyl sulfate, ethyl trimethylsilyl sulfate, 2-propynyl trimethylsilyl sulfate, dilithium ethylene
Disulfate, 2-butyne-1,4-diyl dimethane sulfonate, 2-butyne-1
,4-diyl diethanesulfonate, 2-butyne-1,4-diyl diformate, 2
-Butyne-1,4-diyl diacetate, 2-butyne-1,4-diyl dipropionate, 4-hexadiyn-1,6-diyl dimethanesulfonate, 2-propynyl methanesulfonate, 1-methyl-2-propynyl methanesulfonate , 1,1-dimethyl-2-propynyl methanesulfonate, 2-propynyl ethanesulfonate, 2-
Propynyl vinyl sulfonate, methyl 2-propynyl carbonate, ethyl 2
-Propynyl carbonate, bis(2-propynyl) carbonate, methyl 2-propynyl oxalate, ethyl 2-propynyl oxalate, bis(2-propynyl) oxalate, 2-propynyl acetate, 2-propynyl formate, 2-propynyl methacrylate, di(2 -propynyl) glutarate, 2,2-dioxide-1,2-oxathiolan-4-yl acetate, 2,2-dioxide-1,2-oxathiolan-4-yl propionate, 5-methyl-1,2-oxathiolan-4 -one 2,2-dioxide, 5,5-dimethyl-1,2-oxathiolan-4-one 2,
2-Dioxide, 2-isocyanatoethyl acrylate, 2-isocyanatoethyl methacrylate, 2-isocyanatoethyl crotonate, 2-(2-isocyanatoethoxy)ethyl acrylate, 2-(2-isocyanatoethoxy)ethyl methacrylate, 2 -(2-isocyanatoethoxy)ethyl crotonate, 2-allyl succinic anhydride,
2-(1-penten-3-yl)succinic anhydride, 2-(1-hexen-3-yl)succinic anhydride, 2-(1-hepten-3-yl)succinic anhydride, 2-(1- octen-3-yl) succinic anhydride, 2-(1-nonen-3-yl) succinic anhydride, 2-(3-butene-2-
yl) succinic anhydride, 2-(2-methylallyl)succinic anhydride, 2-(3-methyl-3-
buten-2-yl) succinic anhydride, and the like. These may be used alone or in combination of two or more. By adding these auxiliaries, capacity retention characteristics and cycle characteristics after high-temperature storage can be improved.

The amount of other auxiliary agents to be blended is not particularly limited, and is arbitrary as long as it does not significantly impair the effects of the present invention. The amount of other auxiliary agents is preferably 0.01% by mass or more and 5% by mass or less in 100% by mass of the non-aqueous electrolyte. Within this range, the effects of other auxiliary agents are likely to be fully expressed, and it is easy to avoid a situation where battery characteristics such as high load discharge characteristics deteriorate.
The amount of other auxiliary agents is more preferably 0.1% by mass or more, still more preferably 0.2% by mass or more, and more preferably 3% by mass or less, still more preferably 1% by mass or less. .

2. Energy device using a non-aqueous electrolyte The energy device using a non-aqueous electrolyte of the present invention includes a positive electrode, a negative electrode, the non-aqueous electrolyte, together with an electrolyte and a non-aqueous solvent, a fluorine-containing cyclic carbonate, and a fluorine-containing cyclic carbonate, ) is characterized by containing the compound represented by.
Energy devices using the nonaqueous electrolyte of the present invention include lithium batteries, polyvalent cation batteries, metal-air secondary batteries, secondary batteries using S-block metals other than those listed above, lithium ion capacitors, electric double layer capacitors, etc. are preferred, lithium batteries and lithium ion capacitors are more preferred, and lithium batteries are even more preferred. The nonaqueous electrolyte used in these energy devices is also preferably a so-called gel electrolyte, which is pseudo-solidified with a polymer, filler, or the like.

2-1. Lithium Battery A lithium battery using the non-aqueous electrolyte of the present invention includes a positive electrode having a current collector and a positive electrode active material layer provided on the current collector, a current collector and a positive electrode active material layer provided on the current collector. The present invention comprises a negative electrode having a negative electrode active material layer and capable of occluding and releasing ions, and the above-mentioned non-aqueous electrolyte of the present invention. Note that the lithium battery in the present invention is a general term for a lithium primary battery and a lithium secondary battery.

2-1-1. Battery Configuration The lithium battery of the present invention is the same as a conventionally known lithium battery except for the above-mentioned non-aqueous electrolyte of the present invention. Usually, a positive electrode and a negative electrode are laminated with a porous membrane (separator) impregnated with the non-aqueous electrolyte of the present invention interposed therebetween, and these are housed in a case (exterior body). Therefore, the shape of the lithium battery of the present invention is not particularly limited, and may be cylindrical, prismatic, laminated, coin-shaped, large-sized, or the like.

2-1-2. Non-Aqueous Electrolyte As the non-aqueous electrolyte, the above-mentioned non-aqueous electrolyte of the present invention is used. Note that it is also possible to mix and use other non-aqueous electrolytes with the non-aqueous electrolyte of the present invention without departing from the spirit of the present invention.

2-1-3. Negative electrode The negative electrode according to the present invention has a negative electrode active material layer on a current collector, and the negative electrode active material layer contains a negative electrode active material. The negative electrode active material will be described below.
The negative electrode active material is not particularly limited as long as it can electrochemically release metal ions. The negative electrode active material used in the lithium primary battery is not particularly limited as long as it can electrochemically release lithium ions. A specific example thereof is metallic lithium. The negative electrode active material used in the lithium secondary battery is not particularly limited as long as it is capable of electrochemically intercalating and deintercalating metal ions (for example, lithium ions). Specific examples of negative electrode active materials capable of releasing lithium ions include carbonaceous materials, alloy materials, lithium-containing metal composite oxide materials, and the like. These may be used alone or in any combination of two or more.

<Negative electrode active material>
Examples of the negative electrode active material include carbonaceous materials, alloy materials, lithium-containing metal composite oxide materials, and the like.
Carbonaceous materials used as negative electrode active materials include:
(1) Natural graphite,
(2) A carbonaceous material obtained by heat-treating an artificial carbonaceous substance and an artificial graphite substance at least once in the range of 400 to 3200°C;
(3) a carbonaceous material in which the negative electrode active material layer is made of at least two or more types of carbonaceous substances having different crystallinities and/or has an interface where the carbonaceous substances having different crystallinities are in contact with each other;
(4) A carbonaceous material in which the negative electrode active material layer is made of at least two types of carbonaceous materials having different orientations and/or has an interface where the carbonaceous materials with different orientations come into contact;
A material selected from the following is preferable since it has a good balance of initial irreversible capacity and high current density charge/discharge characteristics. Furthermore, the carbonaceous materials (1) to (4) may be used alone or in combination of two or more in any combination and ratio.

The artificial carbonaceous substances and artificial graphite substances in (2) above include natural graphite, coal-based coke, petroleum-based coke, coal-based pitch, petroleum-based pitch, and oxidation-treated pitches thereof;
Needle coke, pitch coke, carbon materials partially graphitized from these, furnace black, acetylene black, thermal decomposition products of organic materials such as pitch-based carbon fibers, carbonizable organic materials and their carbonized products, or carbonizable organic materials with benzene , solutions dissolved in low-molecular organic solvents such as toluene, xylene, quinoline, and n-hexane, and carbides thereof.

Alloy materials used as negative electrode active materials include lithium alone, single metals and alloys forming lithium alloys, or their oxides, carbides, nitrides, silicides, and sulfides, as long as they can absorb and release lithium. It may be a compound such as a compound or a phosphide, and is not particularly limited. The single metals and alloys forming the lithium alloy are preferably materials containing metals and metalloid elements of groups 13 and 14 (that is, excluding carbon), and more preferably aluminum, silicon, and tin (hereinafter referred to as " These are elemental metals (sometimes abbreviated as "specific metal elements") and alloys or compounds containing these atoms. One type of these may be used alone, or two or more types may be used in combination in any combination and ratio.

The negative electrode active material having at least one type of atom selected from specific metal elements includes an elemental metal of any one type of specific metal element, an alloy consisting of two or more types of specific metal elements, and one or more types of specified metal elements. An alloy consisting of a metal element and one or more other metal elements, and
Compounds containing one or more specific metal elements, and oxides and carbides of the compounds,
Examples include complex compounds such as nitrides, silicides, sulfides, and phosphides. By using these metals, alloys, or metal compounds as the negative electrode active material, it is possible to increase the capacity of the battery.

Also included are compounds in which these composite compounds are complexly combined with several types of elements such as simple metals, alloys, and nonmetallic elements. Specifically, for example, in the case of silicon or tin, an alloy of these elements and a metal that does not function as a negative electrode can be used. For example, in the case of tin, it is possible to use a complex compound containing 5 to 6 types of elements in combination with a metal other than tin and silicon that acts as a negative electrode, a metal that does not function as a negative electrode, and a nonmetallic element. can.

Among these negative electrode active materials, since they have a large capacity per unit mass when used in batteries, metals of any one specific metal element, alloys of two or more specific metal elements, and oxidation of specific metal elements are used. Preferred are metals, carbides, nitrides, etc., and particularly preferred are silicon and/or tin metals, alloys, oxides, carbides, nitrides, etc. from the viewpoint of capacity per unit mass and environmental load.

The lithium-containing metal composite oxide material used as the negative electrode active material is not particularly limited as long as it can absorb and release lithium, but materials containing titanium and lithium are preferred from the viewpoint of high current density charge and discharge characteristics. More preferably, a lithium-containing composite metal oxide material containing titanium is preferred, and further a composite oxide of lithium and titanium (hereinafter sometimes abbreviated as "lithium titanium composite oxide"). That is, it is particularly preferable to use a lithium titanium composite oxide having a spinel structure in a negative electrode active material for an energy device because the output resistance is greatly reduced.

In addition, lithium and titanium of the lithium titanium composite oxide may be mixed with other metal elements, such as Na.
, K, Co, Al, Fe, Ti, Mg, Cr, Ga, Cu, Zn, and Nb.
The metal oxide is a lithium titanium composite oxide represented by the formula (A), where 0.7≦x≦1.5, 1.5≦y≦2.3, 0≦ It is preferable that z≦1.6 because the structure is stable during doping and dedoping of lithium ions.

Li _x Ti _y M _z O ₄ (A)
[In formula (A), M is Na, K, Co, Al, Fe, Ti, Mg, Cr, Ga, Cu, Z
Represents at least one element selected from the group consisting of n and Nb. ]
Among the compositions represented by the above formula (A),
(a) 1.2≦x≦1.4, 1.5≦y≦1.7, z=0
(b) 0.9≦x≦1.1, 1.9≦y≦2.1, z=0
(c) 0.7≦x≦0.9, 2.1≦y≦2.3, z=0
This structure is particularly preferable because it has a good balance of battery performance.
A particularly preferred representative composition of the above compound is (a): Li _4/3 Ti _5/3 O ₄ , (
In b) it is Li ₁ Ti ₂ O ₄ and in (c) it is Li _4/5 Ti _11/5 O ₄ . Also, Z≠
As for the structure of 0, for example, Li _4/3 Ti _4/3 Al _1/3 O ₄ is preferred.

<Configuration and manufacturing method of negative electrode>
Any known method can be used to manufacture the electrode as long as it does not significantly impair the effects of the present invention. For example, it can be formed by adding a binder, a solvent, and if necessary, a thickener, a conductive material, a filler, etc. to a negative electrode active material to form a slurry, applying this to a current collector, drying it, and then pressing it. I can do it.
In addition, when using alloy-based materials, methods such as vapor deposition, sputtering, and plating can be used to
A method of forming a thin film layer (negative electrode active material layer) containing the above-mentioned negative electrode active material can also be used.

(current collector)
Any known current collector can be used as the current collector for holding the negative electrode active material. Examples of the current collector of the negative electrode include metal materials such as aluminum, copper, nickel, stainless steel, and nickel-plated steel, and copper is particularly preferred from the viewpoint of ease of processing and cost.

When the current collector is made of a metal material, examples of the shape of the current collector include metal foil, metal cylinder, metal coil, metal plate, metal thin film, expanded metal, punched metal, and foamed metal. Among these, metal thin films are preferred, copper foils are more preferred, and even more preferred are rolled copper foils produced by rolling methods and electrolytic copper foils produced by electrolytic methods, both of which can be used as the current collector.
The thickness of the current collector is usually 1 μm or more, preferably 5 μm or more, and usually 100 μm or less, preferably 50 μm or less, from the viewpoint of ensuring battery capacity and handling properties.

(Thickness ratio between current collector and negative electrode active material layer)
The ratio of the thickness of the current collector and the negative electrode active material layer is not particularly limited, but the value of "(thickness of the negative electrode active material layer on one side immediately before pouring the non-aqueous electrolyte)/(thickness of the current collector)" is preferably 150 or less, more preferably 20 or less, particularly preferably 10 or less, preferably 0.1 or more, even more preferably 0.4 or more, and particularly preferably 1 or more. When the ratio of the thickness of the current collector to the negative electrode active material layer is within the above range, battery capacity can be ensured and heat generation of the current collector during high current density charging and discharging can be suppressed.

(binder)
The binder for binding the negative electrode active material is not particularly limited as long as it is a material that is stable against non-aqueous electrolytes and solvents used during electrode manufacture.
Specific examples include resin polymers such as polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate, aromatic polyamide, polyimide, cellulose, and nitrocellulose; SBR (styrene butadiene rubber), isoprene rubber, butadiene rubber, fluororubber, NBR Rubber-like polymers such as (acrylonitrile/butadiene rubber), ethylene/propylene rubber; styrene/butadiene/styrene block copolymer or its hydrogenated product; EPDM (ethylene/propylene/diene terpolymer), styrene/ethylene・Thermoplastic elastomeric polymers such as butadiene/styrene copolymer, styrene/isoprene/styrene block copolymer or their hydrogenated products; syndiotactic-1,2-polybutadiene, polyvinyl acetate, ethylene/vinyl acetate, etc. Polymers, soft resinous polymers such as propylene/α-olefin copolymers; fluorine-based polymers such as polyvinylidene fluoride, polytetrafluoroethylene, fluorinated polyvinylidene fluoride, polytetrafluoroethylene/ethylene copolymers; Examples include polymer compositions having ion conductivity for alkali metal ions (particularly lithium ions). These may be used alone or in combination of two or more in any combination and ratio.

The ratio of the binder to the negative electrode active material is preferably 0.1% by mass or more, and 0.5% by mass.
The above is more preferable, 0.6% by weight or more is particularly preferable, 20% by weight or less is preferable, 15% by weight or less is more preferable, still more preferably 10% by weight or less, and particularly preferably 8% by weight or less. When the ratio of the binder to the negative electrode active material is within the above range, battery capacity and strength of the negative electrode can be sufficiently ensured.

In particular, when containing a rubbery polymer represented by SBR as a main component, the ratio of binder to negative electrode active material is usually 0.1% by mass or more, preferably 0.5% by mass or more, and 0.1% by mass or more, preferably 0.5% by mass or more, It is more preferably .6% by mass or more, and usually 5% by mass or less, preferably 3% by mass or less, and even more preferably 2% by mass or less. In addition, when a fluorine-based polymer represented by polyvinylidene fluoride is contained as a main component, its proportion to the negative electrode active material is usually 1% by mass or more, preferably 2% by mass or more, and even more preferably 3% by mass or more. The content is preferably 15% by mass or less, preferably 10% by mass or less, and more preferably 8% by mass or less.

(slurry forming solvent)
There are no particular restrictions on the type of solvent used to form the slurry, as long as it can dissolve or disperse the negative electrode active material, the binder, and the thickener and conductive material used as necessary. Either an aqueous solvent or an organic solvent may be used.
Examples of aqueous solvents include water and alcohol, and examples of organic solvents include N-methylpyrrolidone (NMP), dimethylformamide, dimethylacetamide, methylethylketone, cyclohexanone, methyl acetate, methyl acrylate, diethyltriamine, N,N- Examples include dimethylaminopropylamine, tetrahydrofuran (THF), toluene, acetone, diethyl ether, hexamethylphosphalamide, dimethylsulfoxide, benzene, xylene, quinoline, pyridine, methylnaphthalene, hexane, and the like.
Particularly when using an aqueous solvent, it is preferable to contain a dispersant and the like in addition to a thickener, and to form a slurry using a latex such as SBR. In addition, these solvents may be used alone or in combination of two or more in any combination and ratio.

(thickener)
Thickeners are commonly used to adjust the viscosity of the slurry. The thickener is not particularly limited, but specific examples include carboxymethyl cellulose, methyl cellulose, hydroxymethyl cellulose, ethyl cellulose, polyvinyl alcohol, oxidized starch, phosphorylated starch, casein, and salts thereof. These may be used alone or in combination of two or more in any combination and ratio.

Furthermore, when using a thickener, the ratio of the thickener to the negative electrode active material is usually 0.1% by mass.
The content is preferably 0.5% by mass or more, more preferably 0.6% by mass or more, and usually 5% by mass or less, preferably 3% by mass or less, and even more preferably 2% by mass or less. When the ratio of the thickener to the negative electrode active material is within the above range, a decrease in battery capacity and an increase in resistance can be suppressed, and good applicability can be ensured.

(electrode density)
The electrode structure when the negative electrode active material is made into an electrode is not particularly limited, but the density of the negative electrode active material present on the current collector is preferably 1 g·cm ^-3 or more, and 1.2 g·cm ^-3 or more. is more preferable, more than 1.3 g·cm ⁻³ is particularly preferable, less than 2.2 g·cm ⁻³ is preferable, less than 2.1 g·cm ⁻³ is more preferable, and less than 2.0 g·cm ⁻³ is more preferable. More preferably, it is 1.9 g·cm ^-3 or less. When the density of the negative electrode active material present on the current collector is within the above range, destruction of the negative electrode active material particles can be prevented, and the initial irreversible capacity can be increased or the negative electrode active material particles can be deposited near the current collector/negative electrode active material interface. While it is possible to suppress deterioration of high current density charge/discharge characteristics due to a decrease in permeability of the non-aqueous electrolyte, it is also possible to suppress a decrease in battery capacity and an increase in resistance.

(thickness of negative electrode plate)
The thickness of the negative electrode plate is designed according to the positive electrode plate used and is not particularly limited, but the thickness of the composite material layer after subtracting the thickness of the metal foil of the core material is usually 15 μm or more, preferably 20 μm.
m or more, preferably 30 μm or more, and usually 300 μm or less, preferably 280 μm
The thickness is preferably 250 μm or less, more preferably 250 μm or less.

(Surface coating of negative electrode plate)
Furthermore, the negative electrode plate may have a substance having a different composition adhered to its surface. Substances attached to the surface include oxides such as aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, magnesium oxide, calcium oxide, boron oxide, antimony oxide, and bismuth oxide, lithium sulfate, sodium sulfate, potassium sulfate, magnesium sulfate, and calcium sulfate. , sulfates such as aluminum sulfate, carbonates such as lithium carbonate, calcium carbonate, magnesium carbonate, and the like.

2-1-4. Positive Electrode The positive electrode according to the present invention has a positive electrode active material layer on a current collector, and the positive electrode active material layer contains a positive electrode active material. The positive electrode active material will be described below.

<Cathode active material>
(composition)
The positive electrode active material is not particularly limited as long as it can electrochemically occlude metal ions. The positive electrode active material used in the lithium primary battery is not particularly limited as long as it is capable of electrochemically occluding lithium ions. Specific examples include fluorinated graphite, manganese dioxide, thionyl chloride, iron disulfide, and copper oxide.

The positive electrode active material used in lithium secondary batteries is not particularly limited as long as it can electrochemically intercalate and release metal ions (for example, lithium ions), but for example, lithium and at least one transition metal can be used. Preferred is a substance containing Specific examples include lithium transition metal composite oxides and lithium-containing transition metal phosphate compounds. These may be used alone or in any combination of two or more.

The transition metals of the lithium transition metal composite oxide include V, Ti, Cr, Mn, Fe, Co,
Ni, Cu, etc. are preferable, and specific examples include lithium-cobalt composite oxides such as LiCoO ₂ , lithium-nickel composite oxides such as LiNiO ₂ , LiMnO ₂ , LiMn ₂ O ₄
, Lithium-manganese composite oxide such as Li ₂ MnO ₄ , LiNi _1/3 Mn _1/3 Co ₁
Lithium-nickel-manganese-cobalt composite oxides such as _/3 O ₂ , LiNi _0.5 Mn _0.3 Co _0.2 O ₂ , and some of the transition metal atoms that are the main components of these lithium transition metal composite oxides Na, K, B, F, Al, Ti, V, Cr, Mn, Fe, Co, Li, Ni, C
Examples include those substituted with other elements such as u, Zn, Mg, Ga, Zr, Si, Nb, Mo, Sn, and W. Substituted substances include LiNi _0.5 Mn _0.5 O ₂ , LiNi _{0
．． 85} Co _0.10 Al _0.05 O ₂ , LiNi _0.33 Co _0.33 Mn _0.33 O ₂
, LiNi _0.45 Co _0.10 Al _0.45 O ₂ , LiMn _1.8 Al _0.2 O ₄ , L
Examples include iMn _1.5 Ni _0.5 O ₄ and the like.

Transition metals in the lithium-containing transition metal phosphate compound include V, Ti, Cr, Mn, and Fe.
, Co, Ni, Cu, etc., and specific examples include LiFePO ₄ , Li ₃ Fe ₂ (P
O ₄ ) ₃ , iron phosphates such as LiFeP ₂ O ₇ , cobalt phosphates such as LiCoPO ₄ , and some of the transition metal atoms that are the main components of these lithium transition metal phosphate compounds are replaced with Al, Ti, and V.
, Cr, Mn, Fe, Co, Li, Ni, Cu, Zn, Mg, Ga, Zr, Nb, Si, and other elements substituted.

Further, it is preferable to include lithium phosphate in the positive electrode active material, since this improves continuous charging characteristics. Although there are no restrictions on the use of lithium phosphate, it is preferable to use a mixture of the above positive electrode active material and lithium phosphate. The lower limit of the amount of lithium phosphate used is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, and even more preferably 0.5% by mass, based on the total of the positive electrode active material and lithium phosphate. % or more, and the upper limit is preferably 10% by mass or less, more preferably 8% by mass or less, even more preferably 5% by mass or less.

(Surface coating)
Alternatively, a material having a composition different from this may be used on the surface of the positive electrode active material. Substances attached to the surface include oxides such as aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, magnesium oxide, calcium oxide, boron oxide, antimony oxide, and bismuth oxide, lithium sulfate, sodium sulfate, potassium sulfate, magnesium sulfate, and calcium sulfate. , sulfates such as aluminum sulfate, carbonates such as lithium carbonate, calcium carbonate, and magnesium carbonate, and carbon.

These surface-attached substances can be dissolved or suspended in a solvent and added to the positive electrode active material by impregnation, for example.
A method of drying, a method of dissolving or suspending a surface-adhering material precursor in a solvent and adding it to the cathode active material by impregnation, and a method of reacting by heating, etc., a method of adding it to the cathode active material precursor and baking it at the same time, etc. It can be attached to the surface of the positive electrode active material. In addition, when attaching carbon, it is also possible to use a method of mechanically attaching carbonaceous matter in the form of activated carbon or the like afterwards.

The amount of the surface-attached substance is preferably 0.0 as the lower limit, expressed by mass relative to the positive electrode active material.
It is used in an amount of 1 ppm or more, more preferably 1 ppm or more, still more preferably 10 ppm or more, and the upper limit is preferably 20% or less, more preferably 10% or less, and still more preferably 5% or less. Substances attached to the surface can suppress the oxidation reaction of the electrolyte on the surface of the positive electrode active material and improve battery life, but if the amount attached is too small, the effect will not be fully realized and many If it is too large, the resistance may increase because the ingress and egress of lithium ions is inhibited.
In the present invention, a positive electrode active material to which a substance having a different composition is attached to the surface thereof is also referred to as a "positive electrode active material."

(shape)
Examples of the shape of the particles of the positive electrode active material include conventionally used shapes such as a lump, a polyhedron, a sphere, an ellipsoid, a plate, a needle, and a column. Further, primary particles may aggregate to form secondary particles.

(Production method of positive electrode active material)
As a method for manufacturing the positive electrode active material, a general method for manufacturing inorganic compounds is used.
In particular, various methods can be used to produce spherical or ellipsoidal active materials. For example, a transition metal raw material may be dissolved or pulverized and dispersed in a solvent such as water, and the pH may be adjusted while stirring. After preparing and collecting a spherical precursor and drying it as necessary, LiOH, Li ₂ CO
₃ , a method of adding a Li source such as LiNO ₃ and firing at a high temperature to obtain an active material.

For producing a positive electrode, the above positive electrode active materials may be used alone, or one or more of different compositions may be used in combination in any combination or ratio. In this case, a preferable combination is LiCoO ₂ and LiMn ₂ O ₄ such as LiNi _0.33 Co _0.33 Mn _0.33 O ₂
Or a combination with a part of this Mn replaced with other transition metals, or L
Examples include a combination with iCoO ₂ or Co in which a part of Co is replaced with another transition metal or the like.

<Configuration and manufacturing method of positive electrode>
The configuration of the positive electrode will be described below. In the present invention, the positive electrode can be produced by forming a positive electrode active material layer containing a positive electrode active material and a binder on a current collector. A positive electrode using a positive electrode active material can be produced by a conventional method. That is, a positive electrode active material, a binder, and if necessary a conductive material and a thickener are mixed together in a dry process and formed into a sheet, which is then pressed onto a positive electrode current collector, or these materials are mixed in a liquid medium. A positive electrode can be obtained by dissolving or dispersing the slurry in a slurry, applying the slurry to a positive electrode current collector, and drying it to form a positive electrode active material layer on the current collector.

The content of the positive electrode active material in the positive electrode active material layer is preferably 80% by mass or more, more preferably 82% by mass or more, particularly preferably 84% by mass or more. Also, the upper limit is preferably 99
It is not more than 98% by mass, more preferably not more than 98% by mass. Within the above range, the electric capacity of the positive electrode active material in the positive electrode active material layer can be ensured, and the strength of the positive electrode can be maintained. coating,
The positive electrode active material layer obtained by drying is preferably compacted by hand press, roller press, etc. in order to increase the packing density of the positive electrode active material. The lower limit of the density of the positive electrode active material layer is preferably 1.5 g/cm ³ or more, more preferably 2 g/cm ³ , even more preferably 2.2 g/cm ³ or more, and the upper limit is preferably 5 g/cm 3 or more. ³ or less, more preferably 4.5 g/cm ³ or less, still more preferably 4 g/cm ³ or less. Within the above range, good charge/discharge characteristics can be obtained and an increase in electrical resistance can be suppressed.

(conductive material)
As the conductive material, any known conductive material can be used. Specific examples include metal materials such as copper and nickel; graphite such as natural graphite and artificial graphite; carbon black such as acetylene black; and carbon materials such as amorphous carbon such as needle coke. In addition, these may be used individually by 1 type, and may use 2 or more types together in arbitrary combinations and ratios. The conductive material is usually 0.01% by mass or more, preferably 0.01% by mass or more in the positive electrode active material layer.
．． The content is 1% by mass or more, more preferably 1% by mass or more, and the upper limit is usually 50% by mass or less, preferably 30% by mass or less, more preferably 15% by mass or less. Within the above range, sufficient conductivity and battery capacity can be ensured.

(binder)
The binder used in the production of the positive electrode active material layer is not particularly limited, and in the case of a coating method, any material that can be dissolved or dispersed in the liquid medium used during electrode production may be used, but specific examples include , polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate, polyimide, aromatic polyamide, cellulose, nitrocellulose, and other resin polymers; SBR (styrene-butadiene rubber), NBR (acrylonitrile-butadiene rubber), fluororubber, isoprene rubber Rubbery polymers such as , butadiene rubber, ethylene-propylene rubber; styrene-butadiene-styrene block copolymer or its hydrogenated product, EP
Thermoplastic elastomeric polymers such as DM (ethylene-propylene-diene terpolymer), styrene-ethylene-butadiene-ethylene copolymer, styrene-isoprene-styrene block copolymer or hydrogenated products thereof; Syndiotac Soft resinous polymers such as tic-1,2-polybutadiene, polyvinyl acetate, ethylene/vinyl acetate copolymer, propylene/α-olefin copolymer; polyvinylidene fluoride (PVdF), polytetrafluoroethylene, fluorinated Examples include fluorine-based polymers such as polyvinylidene fluoride and polytetrafluoroethylene/ethylene copolymers; polymer compositions having ion conductivity for alkali metal ions (particularly lithium ions), and the like. In addition, these substances may be used alone or in combination.
More than one species may be used in combination in any combination and ratio.

The proportion of the binder in the positive electrode active material layer is usually 0.1% by mass or more, preferably 1% by mass or more,
More preferably, it is 1.5% by mass or more, and the upper limit is usually 80% by mass or less, preferably 60% by mass.
It is not more than 40% by weight, more preferably not more than 40% by weight, and most preferably not more than 10% by weight. If the proportion of the binder is too low, the positive electrode active material may not be retained sufficiently, resulting in insufficient mechanical strength of the positive electrode, which may deteriorate battery performance such as cycle characteristics. On the other hand, if it is too high, it may lead to a decrease in battery capacity and conductivity.

(slurry forming solvent)
There are no particular restrictions on the type of solvent used to form the slurry, as long as it is capable of dissolving or dispersing the positive electrode active material, conductive material, binder, and thickener used as necessary. Either an aqueous solvent or an organic solvent may be used. Examples of the aqueous medium include water, a mixed medium of alcohol and water, and the like. Examples of organic media include aliphatic hydrocarbons such as hexane; aromatic hydrocarbons such as benzene, toluene, xylene, and methylnaphthalene; heterocyclic compounds such as quinoline and pyridine; ketones such as acetone, methyl ethyl ketone, and cyclohexanone; Esters such as methyl acetate and methyl acrylate; diethylenetriamine, N,N
-Amines such as dimethylaminopropylamine; ethers such as diethyl ether, propylene oxide, and tetrahydrofuran (THF); amides such as N-methylpyrrolidone (NMP), dimethylformamide, and dimethylacetamide; hexamethylphosphalamide, dimethyl Examples include aprotic polar solvents such as sulfoxide.

Particularly when using an aqueous medium, it is preferable to form a slurry using a thickener and a latex such as styrene-butadiene rubber (SBR). Thickeners are commonly used to adjust the viscosity of the slurry. The thickener is not particularly limited, but specific examples include carboxymethyl cellulose, methyl cellulose, hydroxymethyl cellulose, ethyl cellulose, polyvinyl alcohol, oxidized starch, phosphorylated starch, casein, and salts thereof. These may be used alone or in combination of two or more in any combination and ratio. If a thickener is further added, the ratio of the thickener to the active material is 0.1
The content is at least 5% by mass, preferably at least 0.2% by mass, more preferably at least 0.3% by mass, and the upper limit is at most 5% by mass, preferably at most 3% by mass, and more preferably at most 2% by mass. range. Within the above range, good coating properties can be obtained, and a decrease in battery capacity and an increase in resistance can be suppressed.

(current collector)
The material of the positive electrode current collector is not particularly limited, and any known material can be used.
Specific examples include metal materials such as aluminum, stainless steel, nickel plating, titanium, and tantalum; carbon materials such as carbon cloth and carbon paper. Among these, metal materials, particularly aluminum, are preferred.

In the case of metal materials, the shape of the current collector includes metal foil, metal cylinder, metal coil, metal plate, metal thin film, expanded metal, punch metal, foam metal, etc. In the case of carbon materials, carbon plates, carbon Examples include thin films and carbon cylinders. Among these, metal thin films are preferred. Note that the thin film may be formed into a mesh shape as appropriate. The thickness of the thin film is arbitrary, but from the viewpoint of strength and handleability as a current collector, it is usually 1 μm or more, preferably 3 μm or more, more preferably 5 μm or more, and the upper limit is usually 1 mm or less, preferably 100 μm or less. , more preferably 50 μm or less.

Further, it is also preferable that a conductive additive be applied to the surface of the current collector from the viewpoint of reducing the electronic contact resistance between the current collector and the positive electrode active material layer. Examples of the conductive aid include carbon and noble metals such as gold, platinum, and silver.
The ratio of the thickness of the current collector to the positive electrode active material layer is not particularly limited, but the value of (thickness of the positive electrode active material layer on one side immediately before electrolyte injection)/(thickness of the current collector) is 20. It is preferably below, more preferably 15 or less, most preferably 10 or less, and the lower limit is preferably 0.5 or more, more preferably 0.8 or more, and most preferably 1 or more. If it exceeds this range, the current collector may generate heat due to Joule heat during high current density charging and discharging. Within the above range, heat generation of the current collector during high current density charging and discharging can be suppressed, and battery capacity can be ensured.

(electrode area)
When using the electrolytic solution of the present invention, the area of the positive electrode active material layer is preferably larger than the outer surface area of the battery outer case from the viewpoint of increasing stability at high output and high temperatures. Specifically, the total area of the positive electrode relative to the surface area of the exterior of the secondary battery is preferably 15 times or more, more preferably 40 times or more. In the case of a square shape with a bottom, the outer surface area of the outer case refers to the total area calculated from the length, width, and thickness of the case filled with the power generation element, excluding the protruding parts of the terminals. . In the case of a cylindrical shape with a bottom, the geometric surface area is approximated by assuming that the case portion filled with the power generation element excluding the protruding portion of the terminal is a cylinder. The total electrode area of the positive electrode is the geometric surface area of the positive electrode composite material layer facing the composite material layer containing the negative electrode active material. , refers to the sum of the areas calculated for each surface separately.

(Thickness of positive electrode plate)
The thickness of the positive electrode plate is not particularly limited, but from the viewpoint of high capacity and high output, the thickness of the composite material layer after subtracting the thickness of the metal foil of the core material is preferably set as the lower limit for one side of the current collector. is 10 μm or more, more preferably 20 μm or more, and the upper limit is preferably 500 μm or less, more preferably 450 μm or less.

(Surface coating of positive electrode plate)
Furthermore, the positive electrode plate may have a substance having a different composition adhered to its surface. Substances attached to the surface include oxides such as aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, magnesium oxide, calcium oxide, boron oxide, antimony oxide, and bismuth oxide, lithium sulfate, sodium sulfate, potassium sulfate, magnesium sulfate, and calcium sulfate. , sulfates such as aluminum sulfate, carbonates such as lithium carbonate, calcium carbonate, magnesium carbonate, and carbon.

2-1-5. Separator A separator is usually interposed between the positive electrode and the negative electrode to prevent short circuits. In this case, the electrolytic solution of the present invention is usually used by impregnating the separator.
The material and shape of the separator are not particularly limited, and any known materials can be used as long as they do not significantly impair the effects of the present invention. Among these, it is preferable to use a porous sheet or nonwoven fabric that is made of a material that is stable to the electrolytic solution of the present invention, such as a resin, glass fiber, or an inorganic material, and has excellent liquid retention properties. .

Materials for resin and glass fiber separators include polyolefins such as polyethylene and polypropylene, aromatic polyamides, polytetrafluoroethylene, polyethersulfone,
A glass filter or the like can be used. Among these, glass filters and polyolefins are preferred, polyolefins are more preferred, and polypropylene is particularly preferred. One type of these materials may be used alone, two or more types may be used in combination in any combination and ratio, or a layered material may be used. Specific examples of laminated layers of two or more types in any combination include a three-layer separator in which polypropylene, polyethylene, and polypropylene are laminated in this order.

Although the thickness of the separator is arbitrary, it is usually 1 μm or more, preferably 5 μm or more, and 8 μm or more.
It is more preferably 50 μm or more, preferably 40 μm or less, and 3 μm or more.
More preferably, it is 0 μm or less. Within the above range, insulation and mechanical strength can be ensured, while battery performance such as rate characteristics and energy density can be ensured.
Furthermore, when using a porous material such as a porous sheet or a nonwoven fabric as a separator, the porosity of the separator is arbitrary, but is usually 20% or more, preferably 35% or more, more preferably 45% or more, Further, it is usually 90% or less, preferably 85% or less, and more preferably 75% or less. When the porosity is within the above range, insulation and mechanical strength can be ensured, while
It is possible to suppress membrane resistance and obtain good rate characteristics.

The average pore diameter of the separator is also arbitrary, but it is usually 0.5 μm or less, and 0.2 μm or less.
The thickness is preferably 0.05 μm or more, and usually 0.05 μm or more. When the average pore diameter exceeds the above range, short circuits tend to occur. When the average pore diameter is within the above range, short circuits can be prevented, membrane resistance can be suppressed, and good rate characteristics can be obtained. On the other hand, as inorganic materials, oxides such as alumina and silicon dioxide, nitrides such as aluminum nitride and silicon nitride, and sulfates such as barium sulfate and calcium sulfate are used, and those in the form of particles or fibers are used. .

As for the form, those in the form of thin films such as nonwoven fabrics, woven fabrics, and microporous films are used. In the case of a thin film, one having a pore diameter of 0.01 to 1 μm and a thickness of 5 to 50 μm is preferably used.
In addition to the independent thin film configuration described above, a separator can be used in which a composite porous layer containing the inorganic particles is formed on the surface layer of the positive electrode and/or negative electrode using a resin binder. For example, a porous layer may be formed on both sides of the positive electrode using alumina particles having a 90% particle size of less than 1 μm and a fluororesin as a binder.

2-1-6. Battery design <electrode group>
The electrode group has a laminated structure consisting of the above-mentioned positive electrode plate and negative electrode plate with the above-mentioned separator interposed therebetween;
Alternatively, the positive electrode plate and the negative electrode plate may be spirally wound with the separator interposed therebetween. The ratio of the mass of the electrode group to the battery internal volume (hereinafter referred to as electrode group occupancy) is usually 40% or more, preferably 50% or more, and usually 90% or less,
80% or less is preferable. When the electrode group occupancy is within the above range, battery capacity can be secured, and deterioration of characteristics such as charge/discharge repeat performance and high temperature storage due to increase in internal pressure can be suppressed, and furthermore, operation of the gas release valve can be prevented. I can do it.

<Current collection structure>
Although the current collecting structure is not particularly limited, it is preferable to have a structure that reduces the resistance of wiring portions and bonding portions. When the electrode group has the above-mentioned laminated structure, a structure in which the metal core portions of each electrode layer are bundled and welded to a terminal is preferably used. When the area of one electrode becomes large,
Since the internal resistance increases, it is also preferable to provide a plurality of terminals within the electrode to reduce the resistance. When the electrode group has the above-mentioned wound structure, internal resistance can be lowered by providing a plurality of lead structures for each of the positive and negative electrodes and bundling them into a terminal.

<Exterior case>
The material of the outer case is not particularly limited as long as it is stable with respect to the non-aqueous electrolyte used. Specifically, metals such as nickel-plated steel plates, stainless steel, aluminum or aluminum alloys, magnesium alloys, or laminated films of resin and aluminum foil are used. From the viewpoint of weight reduction, aluminum or aluminum alloy metals and laminate films are preferably used.

For exterior cases that use metals, the metals are welded together by laser welding, resistance welding, or ultrasonic welding to create a hermetically sealed structure, or the metals are caulked using a resin gasket. Things can be mentioned. Examples of exterior cases using the above-mentioned laminate film include those in which resin layers are heat-sealed to each other to form a hermetically sealed structure. In order to improve sealing performance, a resin different from the resin used for the laminate film may be interposed between the resin layers. In particular, when creating a sealed structure by heat-sealing a resin layer through a current collector terminal, the metal and resin are joined, so the intervening resin may be a resin with a polar group or a modified resin with a polar group introduced. Resin is preferably used. Further, the shape of the exterior body is also arbitrary, and may be, for example, cylindrical, square, laminated, coin-shaped, large-sized, or the like.

<Protective element>
As a protective element, PTC (Posit
It is possible to use a thermal fuse, a thermistor, a valve (current cutoff valve), etc. that cuts off the current flowing through the circuit due to a sudden rise in the internal pressure or temperature of the battery when abnormal heat generation occurs. It is preferable to select the protection element that does not operate under normal use of high current, and it is more preferable to use a design that does not lead to abnormal heat generation or thermal runaway even without the protection element.

<2-2. Polyvalent cation battery>
An oxide material or the like is used for the positive electrode, and metals such as magnesium, calcium, aluminum, or compounds containing these metals are used for the negative electrode. The electrolyte is a nonaqueous electrolyte solution in which magnesium salts, calcium salts, aluminum salts, etc. are dissolved in a nonaqueous solvent so as to provide the same elements as the reactive active material species of the negative electrode, that is, magnesium ions, calcium ions, and aluminum ions. and at least one compound selected from the group consisting of (A) carboxylic acid ester and (B) compounds represented by formula (1) and formula (2).
The above-mentioned (A) contains a species compound, and the above-mentioned (A)
) A non-aqueous electrolyte for a polyvalent cation battery can be prepared by dissolving the group in a content of 50% by mass or more and 99.5% by mass or less.

<2-3. Metal air battery＞
Metals such as zinc, lithium, sodium, magnesium, aluminum, calcium, and compounds containing these metals are used for the negative electrode. Since the positive electrode active material is oxygen, a porous gas diffusion electrode is used as the positive electrode. Preferably, the porous material is carbon. For the electrolyte, lithium salt, sodium salt, magnesium salt, aluminum salt, calcium salt, etc. are dissolved in a nonaqueous solvent so as to provide the same elements as the negative electrode active material species, that is, lithium, sodium, magnesium, aluminum, calcium, etc. At least one compound selected from the group consisting of (A) carboxylic acid ester and (B) compounds represented by formula (1) and formula (2) is used.
The above-mentioned (A) contains a species compound, and the above-mentioned (A)
) A non-aqueous electrolytic solution for metal-air batteries can be prepared by dissolving the group in a content of 50% by mass or more and 99.5% by mass or less.

<2-4. Secondary batteries using s-block metals other than those listed above>
S-block elements are Group 1 elements (hydrogen, alkali metals), Group 2 elements (beryllium, magnesium, and alkaline earth metals), and helium. - Represents a secondary battery that uses block metal as the negative electrode and/or electrolyte.
Specific examples of S-block metal secondary batteries other than those mentioned above include lithium-sulfur batteries, sodium-sulfur batteries, and sodium ion batteries that use sulfur as the positive electrode.

<2-5. Lithium ion capacitor>
A material that can form an electric double layer is used for the positive electrode, and a material that can insert and release lithium ions is used for the negative electrode. Activated carbon is preferred as the positive electrode material. Further, as the negative electrode material, a carbonaceous material is preferable. The non-aqueous electrolyte contains at least one compound selected from the group consisting of a cyclic carbonate having a carbon-carbon unsaturated bond and a fluorine-containing cyclic carbonate, and a compound represented by formula (1). Uses electrolyte.

<2-6. Electric double layer capacitor>
A material that can form an electric double layer is used for the positive and negative electrodes. Activated carbon is preferred as the positive electrode material and negative electrode material. Non-aqueous electrolytes include
(A) carboxylic acid ester; and (B) at least one compound selected from the group consisting of compounds represented by formula (1) and formula (2).
The above-mentioned (A) contains a species compound, and the above-mentioned (A)
) A non-aqueous electrolytic solution having a content of 50% by mass or more and 99.5% by mass or less is used.

The present invention will be described in more detail below with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.
The structures of the compounds of group (A) used in this example are shown below.

The structures of the compounds of group (B) used in this example are shown below.

Moreover, the structure of the compound used in the comparative example is shown below.

<Examples 1-1 to 1-2 and Comparative Examples 1-1 to 1-6>
[Example 1-1]
[Preparation of non-aqueous electrolyte]
Under a dry argon atmosphere, ethylene carbonate (hereinafter referred to as EC), ethyl methyl carbonate (hereinafter referred to as EMC), compound (A-1) and diethyl carbonate (hereinafter referred to as DE)
LiPF ₆ , which is an electrolyte, was dissolved in a mixed solvent consisting of C). Then, monofluoroethylene carbonate (hereinafter referred to as MFEC) was blended to form the basic electrolyte solution 1.
Furthermore, Example 1-
A non-aqueous electrolyte solution of No. 1 was prepared. This nonaqueous electrolyte contains 14.30% by mass of LiPF ₆ .
, EC is 29.76% by mass, EMC is 14.97% by mass, compound (A-1) is 13.69%.
mass %, DEC 22.04 mass %, MFEC 4.74 mass %, compound (B-1) 0
．． Contains 50% by mass. The content of group (A) relative to the total content of groups (A) and (B) is 9
It is 6.5% by mass.

[Preparation of positive electrode]
97% by mass of lithium cobalt oxide (LiCoO ₂ ) as a positive electrode active material, 1.5% by mass of acetylene black as a conductive material, and 1.5% by mass of polyvinylidene fluoride (PVdF) as a binder.
5% by mass were mixed in an N-methylpyrrolidone solvent using a disperser to form a slurry. This was applied uniformly to both sides of a 15 μm thick aluminum foil, dried, and then pressed to form a positive electrode.

[Preparation of negative electrode]
Natural graphite powder as the negative electrode active material, an aqueous dispersion of sodium carboxymethylcellulose (concentration of sodium carboxymethylcellulose 1% by mass) as the thickener, and an aqueous dispersion of styrene-butadiene rubber (concentration of styrene-butadiene rubber 50% by mass) as the binder. ) and mixed with a disperser to form a slurry. This slurry was uniformly applied to one side of a copper foil having a thickness of 10 μm, dried, and then pressed to form a negative electrode. In addition, in the negative electrode after drying, it was produced so that the mass ratio of natural graphite: sodium carboxymethyl cellulose: styrene butadiene rubber was 98:1:1.

[Preparation of lithium secondary battery]
The above positive electrode, negative electrode, and polypropylene separator are combined into a negative electrode, a separator, a positive electrode,
A battery element was produced by laminating a separator and a negative electrode in this order. This battery element was inserted into a bag made of a laminate film made of aluminum (40 μm thick) coated with resin layers on both sides, with the positive and negative terminals protruding, and then a non-aqueous electrolyte was injected into the bag. Vacuum sealing was performed to produce a sheet-shaped lithium secondary battery.

[Initial charge/discharge test]
With the lithium secondary battery sandwiched between glass plates and pressurized, it was charged at a constant current of 6 hours at a current equivalent to 0.05C at 25°C, and then discharged at a constant current of 0.2C to 3.0V. Furthermore, after constant current-constant voltage charging (also referred to as "CC-CV charging") (0.05C cut) to 4.1V with a current equivalent to 0.2C, the battery charges to 3.0V with a constant current of 0.2C. It discharged. Next, after CC-CV charging (0.05C cut) to 4.4V at 0.2C, 3.
The battery was discharged again to 0V to stabilize the initial battery characteristics. After that, C up to 4.4V at 0.2C.
After C-CV charging (0.05C cut), the battery was discharged again to 3.0V at 0.2C, and this was taken as the initial capacity.
Here, 1C represents the current value that discharges the standard capacity of the battery in 1 hour, for example, 0.2C
represents a current value of 1/5 of that value. The same applies below.

[High temperature storage durability test (post-storage rate characteristics)]
The lithium secondary battery that had been initially charged and discharged was CC-CV charged (0.05C cut) at 0.2C to 4.4V at 25°C, and then stored at high temperature at 85°C for 1 day. . Then, at 25°C, constant current discharge was performed at 0.2C to 3.0V. After that, 25℃
After CC-CV charging (0.05C cut) to 4.4V with a constant current of 0.2C,
The battery was discharged again to 3.0V at 0.5C, and this was taken as the capacity after storage. Furthermore, 4.4 at 0.2C
After CC-CV charging to V (0.05C cut), the battery was discharged to 3.0V at 1.0C, and this was taken as high-rate capacity after storage. At this time, the ratio of the post-storage high rate capacity to the post-storage capacity was determined, and this was defined as the post-storage rate characteristic (%). Note that an improvement in the rate characteristics after storage indicates that the non-aqueous electrolyte in the lithium secondary battery has excellent stability, and that a high-quality coating with high durability and low resistance is formed.
An initial charge/discharge test and a high temperature storage durability test were conducted using the lithium secondary battery produced above. The evaluation results are shown in Table 1 as relative values when Comparative Example 1-1, which will be described later, is taken as 100.0%. The same applies to Example 1-2 and Comparative Examples 1-2 to 1-6 below.

[Example 1-2]
In the non-aqueous electrolyte of Example 1-1, LiPF ₆ was 14.59% by mass and EC was 30.
33% by mass, 27.38% by mass of compound (A-1), 22.47% by mass of DEC, MFE
A lithium secondary battery was produced in the same manner as in Example 1-1, except that a nonaqueous electrolyte containing 4.74% by mass of C and 0.50% by mass of compound (B-1) was used, and the above evaluation was carried out. was carried out. In the nonaqueous electrolyte of Example 1-2, the content of group (A) relative to the total content of groups (A) and (B) was 98.2% by mass.

[Comparative example 1-1]
A lithium secondary battery was produced in the same manner as in Example 1-1, except that a non-aqueous electrolyte containing no compound (A-1) and compound (B-1) was used in the non-aqueous electrolyte of Example 1-1. was prepared and the above evaluation was performed. This nonaqueous electrolyte contains 14.08% by mass of LiPF ₆ and E
C 29.33% by mass, EMC 30.10% by mass, DEC 21.73% by mass, MFE
Contains 4.76% by mass of C.

[Comparative example 1-2]
A lithium secondary battery was produced in the same manner as in Example 1-1, except that a non-aqueous electrolyte containing no compound (A-1) was used in the non-aqueous electrolyte in Example 1-1, and the above-mentioned An evaluation was conducted. This nonaqueous electrolyte contains 14.01% by mass of LiPF ₆ and 29.18% by mass of EC.
, EMC is 29.95% by mass, DEC is 21.62% by mass, MFEC is 4.74% by mass,
Compound (B-1) is contained in an amount of 0.50% by mass. In the non-aqueous electrolyte of Comparative Example 1-2, (
The content of group (A) relative to the total content of groups A) and (B) is 0.0% by mass.

[Comparative example 1-3]
A lithium secondary battery was produced in the same manner as in Example 1-1 except that a non-aqueous electrolyte containing no compound (B-1) was used in the non-aqueous electrolyte of Example 1-1, and the above evaluation was carried out. was carried out. This nonaqueous electrolyte contains 14.37% by mass of LiPF ₆ , 29.91% by mass of EC,
EMC is 15.05% by mass, compound (A-1) is 13.76% by mass, DEC is 22.16% by mass.
It contains 4.76% by mass of MFEC. In the non-aqueous electrolyte of Comparative Example 1-3, (
The content of group (A) relative to the total content of groups A) and (B) is 100.0% by mass.

[Comparative example 1-4]
A lithium secondary battery was produced in the same manner as in Example 1-2 except that a non-aqueous electrolyte containing no compound (B-1) was used in the non-aqueous electrolyte of Example 1-2, and the above evaluation was carried out. was carried out. This nonaqueous electrolyte contains 14.66% by mass of LiPF ₆ , 30.48% by mass of EC,
Compound (A-1) is 27.52% by mass, DEC is 22.58% by mass, MFEC is 4.76%
Contains % by mass. In the non-aqueous electrolyte of Comparative Example 1-4, the content of group (A) relative to the total content of groups (A) and (B) was 100.0% by mass.

[Comparative example 1-5]
In the non-aqueous electrolyte of Example 1-1, compound (C-1) was used instead of compound (B-1).
A lithium secondary battery was produced in the same manner as in Example 1-1 except that 0.50% by mass of was used, and the above evaluation was performed. This nonaqueous electrolyte contains 14.30% by mass of LiPF ₆ , 29.76% by mass of EC, 14.97% by mass of EMC, 13.69% by mass of compound (A-1),
It contains 22.04% by mass of DEC, 4.74% by mass of MFEC, and 0.50% by mass of compound (C-1). In the non-aqueous electrolyte of Comparative Example 1-5, the content of group (A) relative to the total content of groups (A) and (B) was 100.0% by mass.

[Comparative example 1-6]
In the non-aqueous electrolyte of Example 1-2, compound (C-1) was used instead of compound (B-1).
A lithium secondary battery was produced in the same manner as in Example 1-2 except that 0.50% by mass of was used, and the above evaluation was performed. This nonaqueous electrolyte contains 14.59% by mass of LiPF ₆ , 30.33% by mass of EC, 27.38% by mass of compound (A-1), 22.47% by mass of DEC,
It contains 4.74% by mass of MFEC and 0.50% by mass of compound (C-1). Comparative example 1-6
In the non-aqueous electrolyte, the content of group (A) relative to the total content of groups (A) and (B) is 100.0% by mass.

From Table 1, when using the non-aqueous electrolytes of Examples 1-1 and 1-2 according to the present invention, (A
) When neither the compound of group (B) nor the compound of group (B) is added (Comparative Example 1-1)
The initial capacity and post-storage rate characteristics are improved compared to . Furthermore, when the compound of group (A) or group (B) is used alone (Comparative Examples 1-2 to 1-4), both the initial capacity and the rate characteristics after storage are decreased. That is, by adding the compounds of group (A) and compound of group (B) at the same time, the initial capacity is improved by suppressing the decomposition reaction caused by each compound,
It was also suggested that the rate characteristics after storage were improved due to the high quality film formed on the electrode.
In addition, when using a compound that contains a compound of group (A) but is not included in the range of group (B) (Comparative Examples 1-5 and 1-6), although the initial capacity increases, the improvement effect is small; moreover,
The rate characteristics after storage are inferior to Comparative Example 1-1. Therefore, it is clear that the lithium secondary battery using the non-aqueous electrolyte according to the present invention has superior characteristics.

<Example 2-1 and Comparative Examples 2-1 to 2-2>
[Example 2-1]
[Preparation of non-aqueous electrolyte]
LiPF ₆ as an electrolyte was dissolved in a mixed solvent consisting of EC, compound (A-1), and DEC under a dry argon atmosphere. Then, MFEC was blended into the basic electrolyte solution 2.
Further, 0.24% by mass of compound (B-2) was added to the basic electrolyte 2 to prepare a non-aqueous electrolyte of Example 2-1. This nonaqueous electrolyte contains 14.62% by mass of LiPF ₆ and E
Contains 30.41% by mass of C, 27.45% by mass of compound (A-1), 22.53% by mass of DEC, 4.75% by mass of MFEC, and 0.24% by mass of compound (B-2). It can be done. The content of group (A) relative to the total content of groups (A) and (B) is 99.1% by mass.

[Preparation of positive electrode]
It was produced in the same manner as in Example 1-1.
[Preparation of negative electrode]
It was produced in the same manner as in Example 1-1.
[Preparation of lithium secondary battery]
It was produced in the same manner as in Example 1-1 except that the non-aqueous electrolyte prepared in Example 2-1 was used.

[Initial charge/discharge test]
With the lithium secondary battery sandwiched between glass plates and pressurized, it was charged at a constant current of 6 hours at a current equivalent to 0.05C at 25°C, and then discharged at a constant current of 0.2C to 3.0V. Furthermore, after constant current-constant voltage charging (also referred to as "CC-CV charging") (0.05C cut) to 4.1V with a current equivalent to 0.2C, it was left at 45°C for 72 hours. . Then 0
．． It was discharged to 3.0V at a constant current of 2C. Next, after CC-CV charging (0.05C cut) to 4.4V at 0.2C, the battery was discharged again to 3.0V at 0.2C to stabilize the initial battery characteristics. Thereafter, after CC-CV charging (0.05C cut) to 4.4V at 0.2C, the battery was discharged again to 3.0V at 0.2C, and this was taken as the initial capacity.

[High temperature storage durability test (post-storage rate characteristics)]
Evaluation was made in the same manner as in Example 1-1.
An initial charge/discharge test and a high temperature storage durability test were conducted using the lithium secondary battery produced above. The evaluation results are shown in Table 2 as relative values when Comparative Example 2-1, which will be described later, is taken as 100.0%. The same applies to Comparative Example 2-2 below.

[Comparative example 2-1]
A lithium secondary battery was produced in the same manner as in Example 2-1 except that a non-aqueous electrolyte containing no compound (B-2) was used in the non-aqueous electrolyte of Example 2-1, and the above evaluation was carried out. was carried out. This nonaqueous electrolyte contains 14.66% by mass of LiPF ₆ , 30.49% by mass of EC,
Compound (A-1) is 27.51% by mass, DEC is 22.58% by mass, MFEC is 4.76%
Contains % by mass. In the non-aqueous electrolyte of Comparative Example 2-1, the content of group (A) relative to the total content of groups (A) and (B) was 100.0% by mass.

[Comparative example 2-2]
In the non-aqueous electrolyte of Example 2-1, compound (C-2) was used instead of compound (B-2).
A lithium secondary battery was produced in the same manner as in Example 2-1 except that 0.24% by mass of was used, and the above evaluation was performed. This nonaqueous electrolyte contains 14.62% by mass of LiPF ₆ , 30.41% by mass of EC, 27.45% by mass of compound (A-1), 22.53% by mass of DEC,
It contains 4.75% by mass of MFEC and 0.24% by mass of compound (C-2). Comparative example 2-2
In the non-aqueous electrolyte, the content of group (A) relative to the total content of groups (A) and (B) is 100.0% by mass.

Table 2 shows that when the non-aqueous electrolyte of Example 2-1 according to the present invention is used, the initial capacity and post-storage rate Characteristics improve. In other words, by simultaneously adding a compound of group (A) and a compound of group (B), the initial capacity is improved by suppressing the decomposition reaction caused by each compound, and the high-quality It was suggested that the coating improved the rate characteristics after storage.

In addition, when using a compound that contains a compound of group (A) but is not included in group (B) (Comparative Example 2-2), the rate characteristics after storage are improved, but the improvement effect is small; The initial capacity is inferior to Comparative Example 2-1. Therefore, it is clear that the battery using the non-aqueous electrolyte according to the present invention has superior characteristics.

<Examples 3-1 to 3-2 and Comparative Examples 3-1 to 3-6>
[Example 3-1]
[Preparation of non-aqueous electrolyte]
EC, EMC and diethyl carbonate (hereinafter referred to as DEC) under a dry argon atmosphere
(mixed volume ratio EC:EMC:DEC=3:4:3), electrolyte L
iPF ₆ was dissolved at a rate of 1.2 mol/L. Then, 2.0% by mass of vinylene carbonate (hereinafter referred to as VC) and 2.0% by mass of MFEC were blended to form a basic electrolyte solution 3. Furthermore, 9.00% by mass of compound (A-2) and compound (B
-2) A non-aqueous electrolytic solution of Example 3-1 was prepared by blending 0.30% by mass. This non-aqueous electrolyte contains 12.87% by mass of LiPF ₆ , 26.81% by mass of EC, and 27% by mass of EMC.
52% by mass, DEC 19.87% by mass, VC 1.81% by mass, MFEC 1.81% by mass, compound (A-2) 9.00% by mass, compound (B-2) 0. Contains 30% by mass. The content of group (A) relative to the total content of groups (A) and (B) is 96.8% by mass.

[Preparation of positive electrode]
It was produced in the same manner as in Example 1-1.
[Preparation of negative electrode]
It was produced in the same manner as in Example 1-1.
[Preparation of lithium secondary battery]
It was produced in the same manner as Example 1-1 except that the non-aqueous electrolyte prepared in Example 3-1 was used.

[Initial charge/discharge test]
With the lithium secondary battery sandwiched between glass plates and pressurized, it was charged at a constant current of 6 hours at a current equivalent to 0.05C at 25°C, and then discharged at a constant current of 0.2C to 3.0V. was taken as the initial capacity.

[High temperature storage durability test (post-storage rate characteristics)]
The lithium secondary battery that had been initially charged and discharged was CC-CV charged (0.05C cut) at 0.2C to 4.4V at 25°C, and then stored at high temperature at 85°C for 1 day. . Then, at 25°C, constant current discharge was performed at 0.2C to 3.0V. After that, 25℃
After CC-CV charging (0.05C cut) to 4.4V with a constant current of 0.2C,
The battery was discharged again to 3.0V at 0.5C, and this was taken as the capacity after storage. Furthermore, 4.4 at 0.2C
After CC-CV charging to V (0.05C cut), it was discharged to 3.0V at 1.0C, and this was taken as high-rate capacity after storage. At this time, the ratio of the post-storage high rate capacity to the post-storage capacity was determined, and this was defined as the post-storage rate characteristic (%). Note that an improvement in the rate characteristics after storage indicates that the non-aqueous electrolyte in the lithium secondary battery has excellent stability, and that a high-quality coating with high durability and low resistance is formed.
An initial charge/discharge test and a high temperature storage durability test were conducted using the lithium secondary battery produced above. The evaluation results are shown in Table 3 as relative values when Comparative Example 3-1, which will be described later, is taken as 100.0%. The same applies to Example 3-2 and Comparative Examples 3-2 to 3-6 below.

[Example 3-2]
In the non-aqueous electrolyte of Example 3-1, LiPF ₆ was 12.77% by mass and EC was 26%.
61% by mass, 27.31% by mass of EMC, 19.71% by mass of DEC, 1.80% by mass of VC, 1.80% by mass of MFEC, 9.00% by mass of compound (A-2), compound (B-2
) A lithium secondary battery was produced in the same manner as in Example 3-1 except that a non-aqueous electrolyte containing 1.00% by mass was used, and the above evaluation was performed. In the non-aqueous electrolyte of Example 3-2, (A
The content of group (A) relative to the total content of group ) and group (B) is 90.0% by mass.

[Comparative example 3-1]
A lithium secondary battery was produced in the same manner as in Example 3-1 except that a non-aqueous electrolyte containing no compound (A-2) and compound (B-2) was used in the non-aqueous electrolyte of Example 3-1. was prepared and the above evaluation was performed. In this non-aqueous electrolyte,
LiPF ₆ is 14.19% by mass, EC is 29.56% by mass, EMC is 30.34% by mass,
It contains 21.90% by mass of DEC, 2.00% by mass of VC, and 2.00% by mass of MFEC.

[Comparative example 3-2]
A lithium secondary battery was produced in the same manner as in Example 3-1 except that a non-aqueous electrolyte containing no compound (A-2) was used in the non-aqueous electrolyte of Example 3-1, and the above evaluation was carried out. was carried out. This non-aqueous electrolyte contains 14.15% by mass of LiPF ₆ , 29.47% by mass of EC,
EMC is 30.25% by mass, DEC is 21.84% by mass, VC is 1.99% by mass, MFE
It contains 1.99% by mass of C and 0.30% by mass of compound (B-2). In the non-aqueous electrolyte of Comparative Example 3-2, the content of group (A) relative to the total content of groups (A) and (B) is 0.0.
Mass%.

[Comparative example 3-3]
A lithium secondary battery was produced in the same manner as in Example 3-1, except that a non-aqueous electrolyte containing no compound (A-2) was used as the non-aqueous electrolyte in Example 3-2, and the above evaluation was carried out. was carried out. This nonaqueous electrolyte contains 14.05% by mass of LiPF ₆ , 29.27% by mass of EC,
EMC is 30.04% by mass, DEC is 21.68% by mass, VC is 1.98% by mass, MFE
It contains 1.98% by mass of C and 1.00% by mass of compound (B-2). In the non-aqueous electrolyte of Comparative Example 3-3, the content of group (A) relative to the total content of groups (A) and (B) is 0.0.
Mass%.

[Comparative example 3-4]
Comparative Example 3-3 except that a non-aqueous electrolyte containing 27.00% by mass of compound (B-2) was used instead of 1.00% by mass of compound (B-2). A lithium secondary battery was produced in the same manner as in 3-3, and the above evaluation was performed. In this non-aqueous electrolyte, L
iPF ₆ is 10.36% by mass, EC is 21.58% by mass, EMC is 22.15% by mass, D
EC is 15.99% by mass, VC is 1.46% by mass, MFEC is 1.46% by mass, compound (
Contains 27.00% by mass of B-2). In the non-aqueous electrolyte of Comparative Example 3-4, the content of group (A) with respect to the total content of groups (A) and (B) was 0.0% by mass.

[Comparative example 3-5]
A lithium secondary battery was produced in the same manner as in Example 3-1 except that a non-aqueous electrolyte containing no compound (B-2) was used in the non-aqueous electrolyte of Example 3-1, and the above evaluation was carried out. was carried out. This nonaqueous electrolyte contains 12.92% by mass of LiPF ₆ , 26.90% by mass of EC,
EMC is 27.61% by mass, DEC is 19.93% by mass, VC is 1.82% by mass, MFE
It contains 1.82% by mass of C and 9.00% by mass of compound (A-2). In the non-aqueous electrolyte of Comparative Example 3-5, the content of group (A) relative to the total content of groups (A) and (B) was 100
．． It is 0% by mass.

[Comparative example 3-6]
Example except that in the non-aqueous electrolyte of Example 3-1, a non-aqueous electrolyte containing 27.00% by mass of compound (B-2) was used instead of 0.30% by mass of compound (B-2). A lithium secondary battery was produced in the same manner as in 3-1, and the above evaluation was performed. In this non-aqueous electrolyte, L
iPF ₆ 9.08% by mass, EC 18.92% by mass, EMC 19.42% by mass, DE
C was 14.02% by mass, VC was 1.28% by mass, MFEC was 1.28% by mass, compound (A
-2) and 27.00% by mass of compound (B-2) and compound (B-2), respectively. Comparative example 3-6
In the non-aqueous electrolyte, the content of group (A) relative to the total content of groups (A) and (B) is 25.0% by mass.

From Table 3, when using the non-aqueous electrolytes of Examples 3-1 and 3-2 according to the present invention, (A
) When neither the compound of group (B) nor the compound of group (B) is added (Comparative Example 3-1)
The initial capacity and post-storage rate characteristics are improved compared to . Furthermore, when a compound of Group (A) or Group (B) is used alone (Comparative Examples 3-2 to 3-5), the rate characteristics after storage are reduced. In other words, by simultaneously adding a compound of group (A) and a compound of group (B) at a certain specific ratio, the initial capacity is improved by suppressing the decomposition reaction caused by each compound, and It was suggested that the rate characteristics after storage were improved due to the high-quality film produced.

In addition, when the compound of group (A) and the compound of group (B) are outside the specific range of the present invention (Comparative Example 3-6), both the compound of group (A) and the compound of group (B) are Compared to the case where it is not added (Comparative Example 3-1), the initial capacity and rate characteristics after storage are significantly reduced. Therefore, it is clear that the battery using the non-aqueous electrolyte according to the present invention has superior characteristics.

According to the non-aqueous electrolyte of the present invention, it is possible to improve the charge/discharge efficiency and rate characteristics after a high-temperature storage durability test of an energy device containing a non-aqueous electrolyte, and further reduce gas generation after a high-temperature storage durability test, which is useful. It is. Therefore, the non-aqueous electrolyte and energy device of the present invention can be used in various known applications. Specific examples include notebook computers, pen input computers, mobile computers, e-book players, mobile phones, mobile fax machines, mobile copiers, mobile printers, headphone stereos, video movies, LCD televisions,
Handy cleaners, portable CDs, mini discs, transceivers, electronic notebooks, calculators, memory cards, portable tape recorders, radios, backup power supplies, motors, cars, motorcycles, motorized bicycles, bicycles, lighting equipment, toys, game equipment, watches, Examples include power tools, strobes, cameras, home backup power supplies, business backup power supplies, load leveling power supplies, natural energy storage power supplies, etc.

Claims (10)

A non-aqueous electrolytic solution for an energy device comprising a positive electrode and a negative electrode, the non-aqueous electrolytic solution together with an electrolyte and a non-aqueous solvent,
(A) a carboxylic acid ester; and (B) a compound represented by formula (1) , and the content of the (A) group relative to the total content of the (A) group and the (B) group. The amount is 50% by mass or more and 99.5% by mass or less,
The content of the compound represented by the formula (1) based on the total amount of the non-aqueous electrolyte is 0.1% by mass or more and 5 % by mass or less,
A non-aqueous electrolytic solution characterized in that the content of the carboxylic acid ester based on the total amount of the non-aqueous electrolytic solution is 0.6% by mass or more and 70% by mass or less (provided that the embodiment includes a compound represented by formula (0)) except for) .

(In the formula, R ¹ is an unsaturated hydrocarbon group having at least one carbon-carbon unsaturated bond and having 3 to 12 carbon atoms and optionally having a substituent, and the unsaturated hydrocarbon group is has at least one carbon-carbon double bond, and R ² is an aliphatic hydrocarbon group having 2 to 10 carbon atoms. R ⁰³ , R ⁰⁴ and R ⁰⁵ each independently have 1 to 4 carbon atoms; is a hydrocarbyl group, and at least one of R ⁰³ , R ⁰⁴ and R ⁰⁵ is an unsaturated hydrocarbyl group having a triple bond. ) The non-aqueous electrolyte according to claim 1 , wherein the unsaturated hydrocarbon group of R ¹ in the formula (1) is an aliphatic unsaturated hydrocarbon group having at least one carbon-carbon double bond. The non-aqueous electrolytic solution according to claim 1 or 2 , wherein in the formula (1), ^R2 is an alkylene group having 2 or more and 10 or less carbon atoms. The nonaqueous electrolyte according to any one of claims 1 to 3, wherein the content of the compound represented by formula (1) based on the total amount of the nonaqueous electrolyte is 0.3% by mass or more and 3 % by mass or less. Electrolyte. The nonaqueous electrolytic solution according to any one of claims 1 to 4 , wherein the carboxylic acid ester is a propionic acid ester. Furthermore, a cyclic carbonate having a carbon-carbon unsaturated bond, a fluorine-containing cyclic carbonate, a sulfur-containing organic compound, a phosphorus-containing organic compound, an organic compound having a cyano group other than the above formula (1) , an organic compound having an isocyanate group, Any one of claims 1 to 5 , containing at least one compound selected from the group consisting of silicon-containing compounds, monofluorophosphates, difluorophosphates, borates, oxalates, and fluorosulfonates. The non-aqueous electrolyte according to item 1. Cyclic carbonate having a carbon-carbon unsaturated bond, fluorine-containing cyclic carbonate, sulfur-containing organic compound, phosphorus-containing organic compound, organic compound having a cyano group other than the above formula (1) , organic compound having an isocyanate group, silicon-containing The total content of at least one compound selected from the group consisting of compounds, monofluorophosphates, difluorophosphates, borates, oxalates, and fluorosulfonates based on the total amount of the nonaqueous electrolyte is 0. 7. The non-aqueous electrolytic solution according to claim 6 , which has a content of 0.001% by mass or more and 50% by mass or less. An energy device comprising a negative electrode, a positive electrode, and the nonaqueous electrolyte according to any one of claims 1 to 7 . The negative electrode has a negative electrode active material layer on a current collector, and the negative electrode active material layer is made of a single metal, alloy, or compound of silicon, a single metal, alloy, or compound of tin, a carbonaceous material, or a lithium titanium composite. The energy device according to claim 8 , containing at least one selected from the group consisting of oxides. The positive electrode has a positive electrode active material layer on a current collector, and the positive electrode active material layer includes a lithium-cobalt composite oxide, a lithium-cobalt-nickel composite oxide, a lithium-manganese composite oxide, and a lithium-cobalt composite oxide.・Contains at least one selected from the group consisting of manganese composite oxide, lithium-nickel composite oxide, lithium-nickel-manganese composite oxide, and lithium-cobalt-nickel-manganese composite oxide, or 9. The energy device according to 9 .