Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/05—Accumulators with non-aqueous electrolyte
  • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
  • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
  • H01M10/0566—Liquid materials
  • H01M10/0568—Liquid materials characterised by the solutes
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/05—Accumulators with non-aqueous electrolyte
  • H01M10/052—Li-accumulators
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/05—Accumulators with non-aqueous electrolyte
  • H01M10/052—Li-accumulators
  • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/05—Accumulators with non-aqueous electrolyte
  • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
  • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
  • H01M10/0566—Liquid materials
  • H01M10/0567—Liquid materials characterised by the additives
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
  • H01M10/00—Secondary cells; Manufacture thereof
  • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
  • H01M10/4235—Safety or regulating additives or arrangements in electrodes, separators or electrolyte
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
  • Y02E60/10—Energy storage using batteries

Definitions

• This disclosure relates to a non-aqueous electrolyte for batteries, a lithium secondary battery precursor, a lithium secondary battery, and a method for manufacturing a lithium secondary battery.
• Patent Document 1 discloses a battery including a positive electrode active material containing lithium iron phosphate.
• Patent Document 1 Patent No. 5317390
• evaluation items for lithium-ion secondary batteries have become more diverse.
• An object of one aspect of the present disclosure is to provide a nonaqueous electrolyte solution that can improve various characteristics of a lithium ion secondary battery, more specifically, improve the capacity retention rate after high-temperature storage, or reduce the resistance of the battery in a region where the SOC is medium or lower.
• An object of another aspect of the present disclosure is to provide a lithium secondary battery including a nonaqueous electrolyte solution for a battery, the lithium secondary battery having an improved capacity retention rate after high-temperature storage or reduced battery resistance in a region where the SOC is medium or lower, as well as a manufacturing method for a lithium secondary battery and a lithium secondary battery precursor capable of manufacturing the lithium secondary battery.
• a composition comprising a compound (A) and a compound (B),
• the compound (A) is at least one selected from the group consisting of a compound (1) represented by the following formula (1), a compound (2) which is at least one selected from the group consisting of lithium monofluorophosphate and lithium difluorophosphate, a compound (3) represented by the following formula (3), a compound (4) represented by the following formula (4), a compound (5) represented by the following formula (5), a compound (6) represented by the following formula (6), a compound (7) represented by the following formula (7), and a compound (8) represented by the following formula (8)
• the compound (B) is at least one selected from the group consisting of a compound (9) represented by the following formula (9), a compound (10) represented by the following formula (10), and a compound (11) represented by the following formula (11):
• R 11 represents an alkylene group having 1 to 6 carbon atoms, an alkenylene group having 2 to 6 carbon atoms, a group represented by formula (i-1), a group represented by formula (i-2), or a group represented by formula (i-3);
• R 12 represents an oxygen atom, an alkylene group having 1 to 6 carbon atoms, an alkenylene group having 2 to 6 carbon atoms, or an oxymethylene group, * represents a bonding position
• R 13 represents an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, or a hydrogen atom, * represents a bonding position
• R 14 represents a halogen atom, an alkyl group having 1 to 6 carbon atoms, a halogenated alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a group represented by formula (i-4),
• M represents an alkali metal
• b represents an integer of 1 to 3
• m represents an integer of 1 to 4
• n represents an integer from 0 to 8
• q represents 0 or 1
• R 31 represents an alkylene group having 1 to 10 carbon atoms, a halogenated alkylene group having 1 to 10 carbon atoms, an arylene group having 6 to 20 carbon atoms, or a halogenated arylene group having 6 to 20 carbon atoms (these groups may contain a substituent or a heteroatom in the structure, and when q is 1 and m is 2 to 4, m R 31s may each be bonded to each other);
• R 32 represents a halogen atom, an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 20 carbon atoms, or a halogenated aryl group having 6 to 20 carbon atoms (these groups may contain a substituent
• R 41 and R 42 each independently represent a hydrogen atom, a fluorine atom, a hydrocarbon group having 1 to 3 carbon atoms, or a fluorohydrocarbon group having 1 to 3 carbon atoms.
• R 51 to R 54 each independently represent a hydrogen atom, a fluorine atom, a hydrocarbon group having 1 to 3 carbon atoms, or a fluorohydrocarbon group having 1 to 3 carbon atoms, and the double line consisting of a solid line and a dotted line represents a single bond or a double bond.
• R 61 each independently represents a fluorine atom or a fluorohydrocarbon group having 1 to 6 carbon atoms; M represents an alkali metal.
• R 71 each independently represents a hydrocarbon group having 1 to 10 carbon atoms or a trialkylsilyl group having 3 to 18 carbon atoms.
• R 81 represents an alkylene group having 1 to 10 carbon atoms or a halogenated alkylene group having 1 to 10 carbon atoms;
• Each R 82 independently represents a hydrocarbon group having 1 to 10 carbon atoms, or a halogenated hydrocarbon group having 1 to 10 carbon atoms (however, two R 82 may be bonded to each other to form a divalent hydrocarbon group having 1 to 10 carbon atoms, or a divalent halogenated hydrocarbon group having 1 to 10 carbon atoms).
• R 91 and R 92 each independently represent an alkyl group having 1 to 10 carbon atoms (at least one hydrogen atom of the alkyl group may be substituted with a halogen atom), an alkenyl group having 2 to 10 carbon atoms (at least one hydrogen atom of the alkenyl group may be substituted with a halogen atom), an alkynyl group having 2 to 10 carbon atoms (at least one hydrogen atom of the alkynyl group may be substituted with a halogen atom), an aryl group (at least one hydrogen atom of the aryl group may be substituted with a halogen atom, an alkoxy group having 1 to 6 carbon atoms, or an alkyl group having 1 to 6 carbon atoms), or a halogen atom; L 1 and L 2 each independently represent a single bond or -O-.
• R 101 to R 103 each independently represent a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms.
• R 111 represents a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms, or a fluorinated hydrocarbon group having 1 to 10 carbon atoms;
• R 112 and R 113 each independently represent a hydrogen atom, a cyano group, a hydrocarbon group having 1 to 6 carbon atoms, a hydrocarbon group having 1 to 6 carbon atoms and a cyano group, or a halogenated hydrocarbon group having 1 to 6 carbon atoms (with the proviso that at least one of R 112 and R 113 is a cyano group or a hydrocarbon group having 1 to 6 carbon atoms and a cyano group);
• M represents an alkali metal.
• the compound (A) comprises the compound (2) and at least one selected from the group consisting of the compound (3), the compound (4), the compound (5), the compound (6), the compound (7), and the compound (8), The nonaqueous electrolyte solution for a battery according to ⁇ 1>, wherein the compound (B) is the compound (9).
• the compound (A) comprises the compound (1) and at least one selected from the group consisting of the compound (2), the compound (3), the compound (4), the compound (5), the compound (6), the compound (7), and the compound (8), The nonaqueous electrolyte solution for a battery according to ⁇ 1>, wherein the compound (B) is the compound (9).
• the compound (A) is composed of the compound (1), The nonaqueous electrolyte solution for a battery according to ⁇ 1>, wherein the compound (B) is at least one selected from the group consisting of the compound (9), the compound (10), and the compound (11).
• ⁇ 5> The nonaqueous electrolyte solution for a battery according to ⁇ 1>, wherein the compound (A) includes the compound (5).
• ⁇ 6> The nonaqueous electrolyte solution for a battery according to ⁇ 1>, wherein the compound (A) includes the compound (7).
• ⁇ 7> The nonaqueous electrolyte solution for a battery according to ⁇ 1>, wherein the compound (A) includes the compound (8).
• the nonaqueous electrolyte for a battery according to ⁇ 1> which is used for a lithium secondary battery including a positive electrode active material containing lithium metal phosphate.
• the compound (A) is composed of at least one selected from the group consisting of the compound (1), the compound (2), the compound (3), and the compound (4), The nonaqueous electrolyte solution for a battery according to ⁇ 8>, wherein the compound (B) is at least one selected from the group consisting of the compound (9) and the compound (10).
• ⁇ 10> A case, a positive electrode, a negative electrode, a separator, and an electrolyte solution contained in the case; Equipped with the positive electrode comprises a positive electrode active material including lithium metal phosphate;
• the electrolyte solution is the nonaqueous electrolyte solution for a battery according to any one of ⁇ 1> to ⁇ 9>.
• ⁇ 11> A lithium secondary battery obtained by charging and discharging the lithium secondary battery precursor according to ⁇ 10>.
• ⁇ 12> A step of preparing a lithium secondary battery precursor according to ⁇ 10>; charging and discharging the lithium secondary battery precursor;
• a method for producing a lithium secondary battery comprising:
• a nonaqueous electrolyte for a battery that can improve the capacity retention rate during storage of a battery that includes a positive electrode active material that includes lithium metal phosphate.
• a lithium secondary battery including a positive electrode containing a positive electrode active material including lithium metal phosphate and a nonaqueous electrolyte solution for a battery, the lithium secondary battery having an improved capacity retention rate during storage, as well as a method for producing a lithium secondary battery and a lithium secondary battery precursor capable of producing the lithium secondary battery.
• FIG. 1 is a schematic cross-sectional view showing a laminated battery, which is an example of a lithium secondary battery precursor according to the present disclosure.
• FIG. 2 is a schematic cross-sectional view showing a coin-type battery, which is another example of a lithium secondary battery precursor according to the present disclosure.
• a numerical range expressed using “to” means a range that includes the numerical values before and after “to” as the lower and upper limits.
• the amount of each component in a composition means, when a plurality of substances corresponding to each component are present in the composition, the total amount of the plurality of substances present in the composition, unless otherwise specified.
• the term "process” refers not only to an independent process, but also to a process that cannot be clearly distinguished from other processes, as long as the intended purpose of the process is achieved.
• Nonaqueous electrolyte for batteries contains compound (A) and compound (B).
• Compound (A) is a compound (1) represented by formula (1) described later, compound (2) which is at least one selected from the group consisting of lithium monofluorophosphate and lithium difluorophosphate, Compound (3) represented by formula (3) described later, compound (4) represented by formula (4) described later, compound (5) represented by formula (5) described later, and A compound represented by the following formula (6): (6) a compound represented by the following formula (7): (7) a compound represented by the following formula (8): At least one type.
• Compound (B) is a compound (9) represented by formula (9) described later, a compound (10) represented by formula (10) described later, and a compound (11) represented by formula (12) described later.
• the nonaqueous electrolyte is at least one selected from the group consisting of a lithium secondary battery including a positive electrode active material containing lithium metal phosphate (for example, the lithium secondary battery of the present disclosure described later). ) is preferably used.
• the inventors' investigations have revealed that there is room to reduce the capacity retention rate of a lithium secondary battery after high-temperature storage or the resistance in the medium or lower SOC (State of Charge) range (e.g., the 50% SOC range; the same applies below).
• the nonaqueous electrolyte of the present disclosure can improve the capacity retention rate after high-temperature storage or reduce the resistance of the battery in the medium or lower SOC range. This is thought to be because the nonaqueous electrolyte of the present disclosure contains compound (A) and compound (B), and thus a coating with excellent electrode protection effect or a coating with low resistance in the medium or lower SOC range is formed on the electrode surface.
• the nonaqueous electrolyte solution of the present disclosure contains compound (A).
• Compound (A) is at least one selected from the group consisting of compound (1) represented by formula (1) described below, compound (2) which is at least one selected from the group consisting of lithium monofluorophosphate and lithium difluorophosphate, compound (3) represented by formula (3) described below, compound (4) represented by formula (4) described below, compound (5) represented by formula (5) described below, compound (6) represented by formula (6) described below, compound (7) represented by formula (7) described below, and compound (8) represented by formula (8) described below.
• the content of compound (A) (total content when two or more types are used) is preferably 0.01% by mass to 5.0% by mass, more preferably 0.05% by mass to 3.0% by mass, even more preferably 0.10% by mass to 2.5% by mass, and even more preferably 0.10% by mass to 2.0% by mass, based on the total amount of the nonaqueous electrolyte.
• the amount of compound (A) may be reduced compared to the amount added to the non-aqueous electrolyte solution. Even in this case, if even a small amount of compound (A) is detected in the non-aqueous electrolyte solution taken out of the lithium secondary battery, the electrolyte solution of the lithium secondary battery is included in the scope of the non-aqueous electrolyte solution of the present disclosure. The same applies to the compound (B) described below.
• the ratio of the mass content of compound (A) to the mass content of compound (B) is preferably 0.10 to 10, more preferably 0.10 to 5.0, even more preferably 0.10 to 2.0, even more preferably 0.10 to 1.5, even more preferably 0.10 or more and less than 1.0, even more preferably 0.10 to 0.90.
• compound (1) which is one of the options for compound (A), is at least one selected from the group consisting of compounds represented by the following formula (1).
• R 11 represents an alkylene group having 1 to 6 carbon atoms, an alkenylene group having 2 to 6 carbon atoms, a group represented by formula (i-1), a group represented by formula (i-2), or a group represented by formula (i-3); * indicates the bond position.
• R 12 represents an oxygen atom, an alkylene group having 1 to 6 carbon atoms, an alkenylene group having 2 to 6 carbon atoms, or an oxymethylene group, * represents a bonding position
• R 13 represents an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, or a hydrogen atom, * represents a bonding position
• R 14 represents a halogen atom, an alkyl group having 1 to 6 carbon atoms, a halogenated alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a group represented by formula (i-4), * represents a bonding position
• R 15 represents an oxygen atom, an alkylene group having 1 to 6 carbon atoms, an alkenylene group having 2 to 6 carbon atoms, or an oxymethylene group, and * represents the bonding position.
• R 11 is preferably a group represented by formula (i-1) or a group represented by formula (i-2).
• R 12 is preferably an alkylene group having 1 to 3 carbon atoms, an alkenylene group having 1 to 3 carbon atoms, or an oxymethylene group, and more preferably an oxymethylene group.
• R 13 is preferably an alkyl group having 1 to 3 carbon atoms or an alkenyl group having 2 to 3 carbon atoms, and more preferably a propyl group.
• compound (1) examples include the following compound (1)-1, compound (1)-2, and compound (1)-3, with compound (1)-1 being particularly preferred.
• the content of compound (1) relative to the total amount of the nonaqueous electrolyte is preferably 0.01% by mass to 5.0% by mass, more preferably 0.05% by mass to 3.0% by mass, even more preferably 0.10% by mass to 1.5% by mass, and even more preferably 0.10% by mass to 1.0% by mass.
• the compound (A) preferably contains the compound (1).
• compound (A) is It consists of compound (1), or It is preferable that the composition comprises compound (1) and at least one selected from the group consisting of compound (2), compound (3), compound (4), and compound (5). It is more preferable that compound (A) consists of compound (1) and at least one selected from the group consisting of compound (2), compound (3), compound (4), and compound (5).
• the proportion of compound (1) in compound (A) is preferably 50% by mass to 100% by mass, more preferably 60% by mass to 100% by mass, and even more preferably 70% by mass to 90% by mass.
• compound (2) which is one of the options for compound (A)
• compound (2) is at least one selected from the group consisting of lithium monofluorophosphate and lithium difluorophosphate.
• compound (2)-1 is lithium difluorophosphate.
• the content of compound (2) relative to the total amount of the nonaqueous electrolyte is preferably 0.01% by mass to 5.0% by mass, more preferably 0.05% by mass to 3.0% by mass, even more preferably 0.10% by mass to 1.5% by mass, and even more preferably 0.10% by mass to 1.0% by mass.
• Compound (3) which is one of the options for compound (A), is at least one selected from the group consisting of compounds represented by the following formula (3).
• M represents an alkali metal
• b represents an integer of 1 to 3
• m represents an integer of 1 to 4
• n represents an integer from 0 to 8
• q represents 0 or 1
• R 31 represents an alkylene group having 1 to 10 carbon atoms, a halogenated alkylene group having 1 to 10 carbon atoms, an arylene group having 6 to 20 carbon atoms, or a halogenated arylene group having 6 to 20 carbon atoms (these groups may contain a substituent or a heteroatom in the structure, and when q is 1 and m is 2 to 4, m R 31s may each be bonded to each other);
• R 32 represents a halogen atom, an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 20 carbon atoms, or a halogenated aryl group having 6 to 20 carbon atoms (these groups may contain a substituent
• M is an alkali metal.
• the alkali metal include lithium, sodium, potassium, etc. Among these, M is preferably lithium.
• b represents the valence of the anion and the number of cations. b is an integer of 1 to 3, and is preferably 1. When b is 3 or less, the salt of the anion compound is easily dissolved in the mixed organic solvent.
• Each of m and n is a value related to the number of ligands. Each of m and n is determined depending on the type of M.
• m is an integer of 1 to 4.
• n is an integer of 0 to 8.
• q is 0 or 1.
• R 31 represents an alkylene group having 1 to 10 carbon atoms, a halogenated alkylene group having 1 to 10 carbon atoms, an arylene group having 6 to 20 carbon atoms, or a halogenated arylene group having 6 to 20 carbon atoms.
• These alkylene groups, halogenated alkylene groups, arylene groups, or halogenated arylene groups may contain a substituent or a heteroatom in their structure. Specifically, these groups may contain a substituent instead of a hydrogen atom.
• substituents examples include a halogen atom, a linear or cyclic alkyl group, an aryl group, an alkenyl group, an alkoxy group, an aryloxy group, a sulfonyl group, an amino group, a cyano group, a carbonyl group, an acyl group, an amide group, or a hydroxyl group.
• a nitrogen atom, a sulfur atom, or an oxygen atom may be introduced into the structure.
• q is 1 and m is 2 to 4, m R 31s may be bonded to each other.
• An example of such a ligand is ethylenediaminetetraacetic acid.
• R 32 represents a halogen atom, an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group having 1 to 10 carbon atoms, an aryl group having 6 to 20 carbon atoms, or a halogenated aryl group having 6 to 20 carbon atoms.
• these alkyl groups, halogenated alkyl groups, aryl groups, and halogenated aryl groups may contain a substituent or a heteroatom in the structure, and when n is 2 to 8, n R 32 may be bonded to each other to form a ring.
• R 32 is preferably an electron-withdrawing group, and particularly preferably a fluorine atom.
• Q1 and Q2 each independently represent -O- or -CH2- , that is, the ligand is bonded to B (boron atom) via Q1 and Q2 .
• compound (3) include the following compound (3)-1 and compound (3)-2, with compound (3)-1 being particularly preferred.
• the content of compound (3) relative to the total amount of the nonaqueous electrolyte is preferably 0.01% by mass to 5.0% by mass, more preferably 0.05% by mass to 3.0% by mass, even more preferably 0.10% by mass to 1.5% by mass, and even more preferably 0.10% by mass to 1.0% by mass.
• Compound (4) which is one of the options for compound (A), is at least one selected from the group consisting of compounds represented by the following formula (4).
• R 41 and R 42 each independently represent a hydrogen atom, a fluorine atom, a hydrocarbon group having 1 to 3 carbon atoms, or a fluorohydrocarbon group having 1 to 3 carbon atoms.
• the hydrocarbon group having 1 to 6 carbon atoms represented by R 41 and R 42 may be a linear hydrocarbon group or a hydrocarbon group having a branched and/or cyclic structure.
• the hydrocarbon group having 1 to 6 carbon atoms represented by R 41 and R 42 is preferably an alkyl group or an aryl group, more preferably an alkyl group.
• the hydrocarbon group having 1 to 6 carbon atoms, represented by R 41 and R 42 preferably has 1 to 3 carbon atoms, more preferably 1 or 2 carbon atoms, and particularly preferably 1 carbon atom.
• the fluorohydrocarbon group having 1 to 6 carbon atoms represented by R 51 or R 52 may be a linear fluorohydrocarbon group or a fluorohydrocarbon group having a branched and/or cyclic structure.
• the fluorohydrocarbon group having 1 to 6 carbon atoms represented by R 51 or R 52 preferably has 1 to 3 carbon atoms, more preferably 1 or 2 carbon atoms, and particularly preferably 1 carbon atom.
• compound (4) examples include the compound group described in paragraph 0062 of WO 2020/121850.
• compound (4) the following compound (4)-1 is particularly preferable.
• the content of compound (4) relative to the total amount of the nonaqueous electrolyte is preferably 0.01% by mass to 5.0% by mass, more preferably 0.05% by mass to 3.0% by mass, even more preferably 0.10% by mass to 1.5% by mass, and even more preferably 0.10% by mass to 1.0% by mass.
• Compound (5) which is one of the options for compound (A), is at least one selected from the group consisting of compounds represented by the following formula (5).
• R 51 to R 54 each independently represent a hydrogen atom, a fluorine atom, a hydrocarbon group having 1 to 3 carbon atoms, or a fluorohydrocarbon group having 1 to 3 carbon atoms, and the double line consisting of a solid line and a dotted line represents a single bond or a double bond.
• the hydrocarbon group having 1 to 3 carbon atoms represented by R 51 to R 54 may be a straight-chain hydrocarbon group or a hydrocarbon group having a branched structure.
• the hydrocarbon group having 1 to 3 carbon atoms represented by R 51 to R 54 is preferably an alkyl group having 1 to 3 carbon atoms, more preferably an alkyl group having 1 or 2 carbon atoms, and even more preferably an alkyl group having 1 carbon atom.
• the fluorohydrocarbon groups having 1 to 3 carbon atoms represented by R 51 to R 54 may be linear fluorohydrocarbon groups or may be fluorohydrocarbon groups having a branched structure.
• the fluorinated hydrocarbon group having 1 to 3 carbon atoms represented by R 51 to R 54 is preferably a fluorinated alkyl group having 1 to 3 carbon atoms, more preferably a fluorinated alkyl group having 1 or 2 carbon atoms, and even more preferably a fluorinated alkyl group having 1 carbon atom.
• compound (5) examples include the compound group described in paragraph 0085 of WO 2020/121850.
• compound (5) the following compound (5)-1 or the following compound (5)-2 is particularly preferable.
• the content of compound (5) relative to the total amount of the nonaqueous electrolyte is preferably 0.01% by mass to 5.0% by mass, more preferably 0.05% by mass to 3.0% by mass, even more preferably 0.10% by mass to 1.5% by mass, and even more preferably 0.10% by mass to 1.0% by mass.
• Compound (6) which is one of the options for compound (A), is at least one selected from the group consisting of compounds represented by the following formula (6).
• R 61 each independently represents a fluorine atom or a fluorohydrocarbon group having 1 to 6 carbon atoms, and M represents an alkali metal.
• the fluorohydrocarbon group having 1 to 3 carbon atoms represented by R 61 may be a linear fluorohydrocarbon group or a branched fluorohydrocarbon group.
• R 61 is more preferably a fluorine atom (fluoro group, --F), a trifluoromethyl group (--CF 3 ), or a pentafluoroethyl group (--CF 2 CF 3 ).
• M is an alkali metal, and examples of the alkali metal include lithium, sodium, and potassium. Of these, M is preferably lithium.
• the content of compound (6) relative to the total amount of the nonaqueous electrolyte is preferably 0.01% by mass to 5.0% by mass, more preferably 0.05% by mass to 3.0% by mass, even more preferably 0.10% by mass to 1.5% by mass, and even more preferably 0.10% by mass to 1.0% by mass.
• Compound (7) which is one of the options for compound (A), is at least one selected from the group consisting of compounds represented by the following formula (7).
• R 71 each independently represents a hydrocarbon group having 1 to 10 carbon atoms or a trialkylsilyl group having 3 to 18 carbon atoms.
• the hydrocarbon group having 1 to 10 carbon atoms represented by R 71 may be a linear hydrocarbon group, a hydrocarbon group having a branched structure, or a hydrocarbon group having a cyclic structure.
• the hydrocarbon group having 1 to 10 carbon atoms represented by R 71 an alkyl group having 1 to 8 carbon atoms is preferable.
• the trialkylsilyl group having 3 to 18 carbon atoms represented by R 71 is preferably a trimethylsilyl group (-Si(CH 3 ) 3 ), a triethylsilyl group (-Si(C 2 H 5 ) 3 ), a tri-t-butylsilyl group (-Si(tC 4 H 9 ) 3 ), or a triphenylsilyl group (-Si(C 6 H 5 ) 3 ).
• the content of compound (7) relative to the total amount of the nonaqueous electrolyte is preferably 0.01% by mass to 5.0% by mass, more preferably 0.05% by mass to 3.0% by mass, even more preferably 0.10% by mass to 1.5% by mass, and even more preferably 0.10% by mass to 1.0% by mass.
• Compound (8) which is one of the options for compound (A), is at least one selected from the group consisting of compounds represented by the following formula (8).
• R 81 represents an alkylene group having 1 to 10 carbon atoms or a halogenated alkylene group having 1 to 10 carbon atoms
• R 82 each independently represents a hydrocarbon group having 1 to 10 carbon atoms or a halogenated hydrocarbon group having 1 to 10 carbon atoms (however, two R 82 may be bonded to each other to form a divalent hydrocarbon group having 1 to 10 carbon atoms or a divalent halogenated hydrocarbon group having 1 to 10 carbon atoms).
• the alkylene group having 1 to 10 carbon atoms represented by R 81 may be a linear alkylene group or an alkylene group having a branched structure.
• the alkylene group having 1 to 10 carbon atoms represented by R 81 is preferably an alkylene group having 1 to 3 carbon atoms, more preferably an alkylene group having 1 or 2 carbon atoms, and particularly preferably a methylene group.
• the halogenated alkylene group having 1 to 10 carbon atoms represented by R 81 may be a linear halogenated alkylene group or a branched alkylene group.
• the halogenated alkylene group having 1 to 10 carbon atoms represented by R 81 is preferably a halogenated alkylene group having 1 to 3 carbon atoms, more preferably a halogenated alkylene group having 1 or 2 carbon atoms, and particularly preferably a difluoromethylene group.
• the hydrocarbon group having 1 to 10 carbon atoms represented by R 82 may be a straight-chain hydrocarbon group or a hydrocarbon group having a branched structure.
• the hydrocarbon group having 1 to 10 carbon atoms represented by R 82 is preferably a hydrocarbon group having 1 to 3 carbon atoms, more preferably a hydrocarbon group having 1 or 2 carbon atoms, and particularly preferably a methyl group.
• the halogenated hydrocarbon group having 1 to 10 carbon atoms represented by R 82 may be a linear halogenated hydrocarbon group or a branched halogenated hydrocarbon group.
• the halogenated hydrocarbon group having 1 to 10 carbon atoms represented by R 82 is preferably a halogenated hydrocarbon group having 1 to 3 carbon atoms, more preferably a halogenated hydrocarbon group having 1 or 2 carbon atoms, and particularly preferably a trifluoromethyl group.
• the divalent hydrocarbon group having 1 to 10 carbon atoms or the divalent halogenated hydrocarbon group having 1 to 10 carbon atoms sandwiched between the two oxa groups (-O-) may be a straight-chain hydrocarbon group or halogenated hydrocarbon group, or a hydrocarbon group or halogenated hydrocarbon group having a branched structure.
• the divalent hydrocarbon group having 1 to 10 carbon atoms or the divalent halogenated hydrocarbon group having 1 to 10 carbon atoms sandwiched between the two oxa groups (-O-) is preferably a methylene group, a difluoromethylene group, an ethylene group, or a tetrafluoroethylene group.
• compound (8) include the following compounds (8)-1 to (8)-13, with the following compound (8)-1 being particularly preferred.
• the content of compound (8) relative to the total amount of the nonaqueous electrolyte is preferably 0.01% by mass to 5.0% by mass, more preferably 0.05% by mass to 3.0% by mass, even more preferably 0.10% by mass to 1.5% by mass, and even more preferably 0.10% by mass to 1.0% by mass.
• the nonaqueous electrolyte solution of the present disclosure contains a compound (B).
• Compound (B) is at least one selected from the group consisting of compound (9) represented by formula (9) described below, compound (10) represented by formula (10) described below, and compound (11) represented by formula (11) described below.
• the content of compound (B) (total content when two or more types are used) is preferably 0.01 mass% to 5.0 mass%, more preferably 0.05 mass% to 3.0 mass%, further preferably 0.10 mass% to 1.5 mass%, and particularly preferably 0.20 mass% to 1.5 mass%, based on the total amount of the nonaqueous electrolyte.
• the preferred range of the content mass ratio [compound (A)/compound (B)] is as described above.
• Compound (9), which is one of the options for compound (B), is at least one selected from the group consisting of compounds represented by the following formula (9).
• Compound (9) is included in the lithium (N-carbonyl)sulfonamide compounds.
• R 91 and R 92 each independently represent an alkyl group having 1 to 10 carbon atoms (at least one hydrogen atom of the alkyl group may be substituted with a halogen atom), an alkenyl group having 2 to 10 carbon atoms (at least one hydrogen atom of the alkenyl group may be substituted with a halogen atom), an alkynyl group having 2 to 10 carbon atoms (at least one hydrogen atom of the alkynyl group may be substituted with a halogen atom), an aryl group (at least one hydrogen atom of the aryl group may be substituted with a halogen atom, an alkoxy group having 1 to 6 carbon atoms, or an alkyl group having 1 to 6 carbon atoms), or a halogen atom; L 1 and L 2 each independently represent a single bond or -O-.
• the "alkyl group having 1 to 10 carbon atoms" represented by each of R 91 and R 92 is a straight-chain or branched-chain alkyl group having from 1 to 10 carbon atoms.
• Examples of the "alkyl group having 1 to 10 carbon atoms” include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a 2-methylbutyl group, a 1-methylpentyl group, a neopentyl group, a 1-ethylpropyl group, a hexyl group, a 3,3-dimethylbutyl group, a heptyl group, an octyl group, a nonyl group, and a decyl group.
• the "alkyl group having 1 to 10 carbon atoms” is preferably an alkyl group having 1 to 6 carbon atoms, and more preferably an alkyl group having 1 to 3 carbon atoms. At least one hydrogen atom of the "alkyl group having 1 to 10 carbon atoms" may be substituted with a halogen atom.
• the halogen atom is preferably a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, more preferably a fluorine atom, a chlorine atom, or a bromine atom, further preferably a fluorine atom or a chlorine atom, and particularly preferably a fluorine atom.
• the number of hydrogen atoms substituted with halogen atoms is not particularly limited and is appropriately selected depending on the number of carbon atoms in the alkyl group, with 1 to 7 being preferred.
• the "alkenyl group having 2 to 10 carbon atoms” represented by each of R 91 and R 92 is a straight-chain or branched-chain alkenyl group having from 2 to 10 carbon atoms.
• Examples of the "alkenyl group having 2 to 10 carbon atoms” include a vinyl group, a 2-propenyl group, a 2-butenyl group, a 3-butenyl group, a 2-pentenyl group, a 3-pentenyl group, a 4-pentenyl group, and a 5-hexenyl group.
• the "alkenyl group having 2 to 10 carbon atoms” is preferably an alkenyl group having 2 to 6 carbon atoms, and more preferably an alkenyl group having 2 to 3 carbon atoms. At least one hydrogen atom of the "alkenyl group having 2 to 10 carbon atoms" may be substituted with a halogen atom.
• the halogen atom is preferably a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, more preferably a fluorine atom, a chlorine atom, or a bromine atom, further preferably a fluorine atom or a chlorine atom, and particularly preferably a fluorine atom.
• the number of hydrogen atoms substituted with halogen atoms is not particularly limited and is appropriately selected depending on the number of carbon atoms in the alkenyl group, with 1 to 7 being preferred.
• the "alkynyl group having 2 to 10 carbon atoms” represented by each of R 91 and R 92 is a straight-chain or branched-chain alkynyl group having from 2 to 10 carbon atoms.
• Examples of the "alkynyl group having 2 to 10 carbon atoms” include an ethynyl group, a propargyl group (2-propynyl group), a 2-butynyl group, a 3-butynyl group, a 2-pentynyl group, a 3-pentynyl group, a 4-pentynyl group, and a 5-hexynyl group.
• the "alkynyl group having 2 to 10 carbon atoms” is preferably an alkynyl group having 2 to 6 carbon atoms, and more preferably an alkynyl group having 2 to 3 carbon atoms.
• At least one hydrogen atom of the "alkynyl group having 2 to 10 carbon atoms" may be substituted with a halogen atom.
• the halogen atom is preferably a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, more preferably a fluorine atom, a chlorine atom, or a bromine atom, further preferably a fluorine atom or a chlorine atom, and particularly preferably a fluorine atom.
• the number of hydrogen atoms substituted with halogen atoms is not particularly limited and is appropriately selected depending on the number of carbon atoms in the alkynyl group, with 1 to 7 being preferred.
• the "aryl group” represented by each of R 91 and R 92 includes a phenyl group or a naphthyl group, and a phenyl group is preferable.
• At least one hydrogen atom of the "aryl group" represented by each of R 91 and R 92 may be substituted with a halogen atom, an alkoxy group having 1 to 6 carbon atoms, or an alkyl group having 1 to 6 carbon atoms.
• the halogen atom is preferably a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, more preferably a fluorine atom, a chlorine atom, or a bromine atom, further preferably a fluorine atom or a chlorine atom, and particularly preferably a fluorine atom.
• the number of hydrogen atoms substituted with halogen atoms is not particularly limited, and is preferably 1 to 5.
• the alkyl group may be linear, branched, or cyclic.
• the alkoxy group having 1 to 6 carbon atoms include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, a t-butoxy group, and a pentyloxy group.
• the alkoxy group having 1 to 6 carbon atoms is preferably an alkoxy group having 1 to 3 carbon atoms, and more preferably a methoxy group or an ethoxy group.
• the number of hydrogen atoms substituted by the alkoxy group having 1 to 6 carbon atoms is not particularly limited, and is preferably 1 to 3.
• the alkyl group having 1 to 6 carbon atoms may be linear, branched, or cyclic.
• Examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, a t-butyl group, an n-pentyl group, an n-hexyl group, and a cyclohexyl group.
• the alkyl group having 1 to 6 carbon atoms is preferably an alkyl group having 1 to 3 carbon atoms, and more preferably a methyl group or an ethyl group.
• the number of hydrogen atoms substituted by the alkyl group having 1 to 6 carbon atoms is not particularly limited, and is preferably 1 to 3.
• the "halogen atom" represented by each of R 91 and R 92 is preferably a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, more preferably a fluorine atom, a chlorine atom, or a bromine atom, still more preferably a fluorine atom or a chlorine atom, and particularly preferably a fluorine atom.
• L 1 and L 2 each independently represent a single bond or —O—.
• L 1 and L 2 are Preferably, L 1 is -O- and L 2 is a single bond or -O-; or a combination in which L 2 is -O- and L 1 is a single bond or -O-; More preferred is a combination in which L 2 is --O-- and L 1 is a single bond or --O--, and particularly preferred is a combination in which L 2 is --O-- and L 1 is a single bond.
• R 92 and L 2 are A preferred combination is one in which R 92 is an alkyl group having 1 to 3 carbon atoms (at least one hydrogen atom of the alkyl group may be substituted with a halogen atom) and L 2 is --O--.
• R 91 is a halogen atom and L 1 is a single bond. More preferably, R 91 is a fluorine atom and L 1 is a single bond.
• compound (9) include the group of compounds described in paragraphs 0206 to 0418 of WO 2022/196230.
• the following compound (9)-1 is particularly preferable.
• the synthesis method of compound (9)-1 reference can be made to paragraphs 0389 to 0391 of WO 2022/196230 (the description of “lithium fluorosulfonylmethoxycarbonylamide [synthetic compound (I-42)]” in Synthesis Example 42).
• compound (B) contains compound (9), the content of compound (9) is preferably 0.01% by mass to 5.0% by mass, more preferably 0.05% by mass to 3.0% by mass, even more preferably 0.10% by mass to 1.5% by mass, and particularly preferably 0.20% by mass to 1.5% by mass, based on the total amount of the nonaqueous electrolyte.
• the compound (B) preferably contains the compound (9).
• compound (B) is or consisting of compound (9): It is preferable that the composition comprises compound (9) and at least one selected from the group consisting of compound (10) and compound (11). It is more preferable that compound (A) consists of compound (9) and at least one selected from the group consisting of compound (10) and compound (11).
• the proportion of compound (9) in compound (B) is preferably 10% by mass to 100% by mass, more preferably 20% by mass to 100% by mass, even more preferably 30% by mass to 100% by mass, and even more preferably 40% by mass to 90% by mass.
• Compound (10), which is one of the options for compound (B), is at least one selected from the group consisting of compounds represented by the following formula (10).
• R 101 to R 103 each independently represent a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms.
• the hydrocarbon group having 1 to 10 carbon atoms represented by R 101 to R 103 may be a straight-chain hydrocarbon group or a hydrocarbon group having a branched structure.
• the hydrocarbon group having 1 to 10 carbon atoms represented by R 101 to R 103 is preferably an alkyl group having 1 to 10 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms, even more preferably an alkyl group having 1 to 3 carbon atoms, even more preferably an alkyl group having 1 or 2 carbon atoms, and even more preferably an alkyl group having 1 carbon atom (i.e., a methyl group).
• R 101 to R 103 are each independently a hydrocarbon group having 1 to 10 carbon atoms (preferably an alkyl group having 1 to 10 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms, even more preferably an alkyl group having 1 to 3 carbon atoms, even more preferably an alkyl group having 1 or 2 carbon atoms, and even more preferably an alkyl group having 1 carbon atom (i.e., a methyl group)).
• a hydrocarbon group having 1 to 10 carbon atoms preferably an alkyl group having 1 to 10 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms, even more preferably an alkyl group having 1 to 3 carbon atoms, even more preferably an alkyl group having 1 or 2 carbon atoms, and even more preferably an alkyl group having 1 carbon atom (i.e., a methyl group)).
• compound (B) contains compound (10)
• the content of compound (10) is preferably 0.01% by mass to 5.0% by mass, more preferably 0.05% by mass to 3.0% by mass, even more preferably 0.10% by mass to 1.5% by mass, and particularly preferably 0.20% by mass to 1.5% by mass, based on the total amount of the nonaqueous electrolyte.
• Compound (11), which is one of the options for compound (B), is at least one selected from the group consisting of compounds represented by the following formula (11).
• R 111 represents a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms, or a fluorinated hydrocarbon group having 1 to 10 carbon atoms
• R 112 and R 113 each independently represent a hydrogen atom, a cyano group, a hydrocarbon group having 1 to 6 carbon atoms, a hydrocarbon group having 1 to 6 carbon atoms and a cyano group, or a halogenated hydrocarbon group having 1 to 6 carbon atoms (with the proviso that at least one of R 112 and R 113 is a cyano group or a hydrocarbon group having 1 to 6 carbon atoms and a cyano group);
• M represents an alkali metal.
• the hydrocarbon group having 1 to 10 carbon atoms represented by R 111 may be a straight-chain hydrocarbon group or a hydrocarbon group having a branched structure.
• the hydrocarbon group having 1 to 10 carbon atoms represented by R 111 is preferably an alkyl group having 1 to 10 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms, even more preferably an alkyl group having 1 to 3 carbon atoms, even more preferably an alkyl group having 1 or 2 carbon atoms, and even more preferably an alkyl group having 1 carbon atom (i.e., a methyl group).
• the fluorohydrocarbon group having 1 to 10 carbon atoms represented by R 111 is a group having a structure in which at least one hydrogen atom in a hydrocarbon group having 1 to 10 carbon atoms is replaced with a fluorine atom.
• Preferred embodiments of the hydrocarbon group having 1 to 10 carbon atoms which serves as the base of the fluorinated hydrocarbon group having 1 to 10 carbon atoms represented by R 111 are the same as the preferred embodiments of the hydrocarbon group having 1 to 10 carbon atoms represented by R 111 described above.
• R 111 is preferably a fluorinated hydrocarbon group having 1 to 10 carbon atoms (preferably a fluorinated alkyl group having 1 to 10 carbon atoms, more preferably a fluorinated alkyl group having 1 to 6 carbon atoms, even more preferably a fluorinated alkyl group having 1 to 3 carbon atoms, even more preferably a fluorinated alkyl group having 1 or 2 carbon atoms, even more preferably an alkyl group having 1 carbon atom, and even more preferably a trifluoromethyl group).
• a fluorinated hydrocarbon group having 1 to 10 carbon atoms preferably a fluorinated alkyl group having 1 to 10 carbon atoms, more preferably a fluorinated alkyl group having 1 to 6 carbon atoms, even more preferably a fluorinated alkyl group having 1 to 3 carbon atoms, even more preferably a fluorinated alkyl group having 1 or 2 carbon atoms, even more preferably an
• R 112 and R 113 each independently represent a hydrogen atom, a cyano group, a hydrocarbon group having 1 to 6 carbon atoms, a hydrocarbon group having 1 to 6 carbon atoms and a cyano group, or a halogenated hydrocarbon group having 1 to 6 carbon atoms, provided that at least one of R 112 and R 113 is a cyano group or a hydrocarbon group having 1 to 6 carbon atoms and a cyano group.
• the hydrocarbon group having 1 to 6 carbon atoms represented by each of R 112 and R 113 may be a straight-chain hydrocarbon group or a hydrocarbon group having a branched structure.
• the hydrocarbon group having 1 to 6 carbon atoms represented by each of R 112 and R 113 is preferably an alkyl group having 1 to 6 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms, even more preferably an alkyl group having 1 or 2 carbon atoms, and still more preferably an alkyl group having 1 carbon atom (i.e., a methyl group).
• the hydrocarbon group having 1 to 6 carbon atoms and having a cyano group represented by each of R 112 and R 113 is a group in which at least one hydrogen atom (preferably one hydrogen atom) in a hydrocarbon group having 1 to 6 carbon atoms is replaced with a cyano group.
• Preferred embodiments of the hydrocarbon group having 1 to 6 carbon atoms which serves as the base of the hydrocarbon group having 1 to 6 carbon atoms and having a cyano group represented by each of R 112 and R 113 are the same as the preferred embodiments of the hydrocarbon group having 1 to 6 carbon atoms represented by each of R 112 and R 113 .
• the halogenated hydrocarbon group having 1 to 6 carbon atoms represented by each of R 112 and R 113 is a group in which at least one hydrogen atom (preferably one hydrogen atom) in a hydrocarbon group having 1 to 6 carbon atoms is replaced with a halogen atom.
• Preferred embodiments of the hydrocarbon group having 1 to 6 carbon atoms which serves as the base for the halogenated hydrocarbon group represented by each of R 112 and R 113 are the same as the preferred embodiments of the hydrocarbon group having 1 to 6 carbon atoms represented by each of R 112 and R 113 .
• the halogen atom in the halogenated hydrocarbon group represented by each of R 112 and R 113 is preferably a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom, more preferably a fluorine atom, a chlorine atom, or a bromine atom, even more preferably a fluorine atom or a chlorine atom, and even more preferably a fluorine atom.
• At least one of R 112 and R 113 is a cyano group or a hydrocarbon group having a cyano group and having 1 to 6 carbon atoms.
• a preferred embodiment of R 112 and R 113 is one in which R 112 and R 113 are each independently a cyano group or a hydrocarbon group having 1 to 6 carbon atoms and a cyano group, and a more preferred embodiment of R 112 and R 113 is one in which both R 112 and R 113 are a cyano group.
• M is an alkali metal.
• the alkali metal include lithium, sodium, potassium, etc. Among these, M is preferably lithium.
• the content of compound (8) is preferably 0.01% by mass to 5.0% by mass, more preferably 0.05% by mass to 3.0% by mass, even more preferably 0.10% by mass to 1.5% by mass, and particularly preferably 0.20% by mass to 1.5% by mass, based on the total amount of the nonaqueous electrolyte.
• the combinations of compounds (A) (1) to (8) and compounds (B) (9) to (11) are not particularly limited, but preferred combinations are exemplified below.
• compound (A) consists of compound (2) and at least one selected from the group consisting of compound (3), compound (4), compound (5), compound (6), compound (7), and compound (8)
• compound (B) consists of compound (9).
• the non-aqueous electrolyte may contain compound (2), compound (3), and compound (9).
• the non-aqueous electrolyte may contain compound (2), compound (4), and compound (9).
• the non-aqueous electrolyte may contain compound (2), compound (5), and compound (9).
• the non-aqueous electrolyte may contain compound (2), compound (6), and compound (9).
• the non-aqueous electrolyte may contain compound (2), compound (7), and compound (9).
• the non-aqueous electrolyte may contain compound (2), compound (8), and compound (9).
• compound (A) consists of compound (1) and at least one selected from the group consisting of compound (2), compound (3), compound (4), compound (5), compound (6), compound (7), and compound (8)
• compound (B) consists of compound (9).
• the non-aqueous electrolyte may contain compound (1), compound (2), and compound (9).
• the non-aqueous electrolyte may contain compound (1), compound (3), and compound (9).
• the non-aqueous electrolyte may contain compound (1), compound (4), and compound (9).
• the non-aqueous electrolyte may contain compound (1), compound (5), and compound (9).
• the non-aqueous electrolyte may contain compound (1), compound (6), and compound (9).
• the non-aqueous electrolyte may contain compound (1), compound (7), and compound (9).
• compound (A) consists of compound (1)
• compound (B) consists of compound (9) and at least one selected from the group consisting of compound (10) and compound (11).
• the nonaqueous electrolyte may contain the compound (1), the compound (9), and the compound (10).
• the nonaqueous electrolyte may contain the compound (1), the compound (9), and the compound (11).
• the compound (A) is a nonaqueous electrolyte solution containing the compound (5).
• the non-aqueous electrolyte may contain the compound (5) and the compound (9).
• the non-aqueous electrolyte may contain the compound (5) and the compound (10).
• the non-aqueous electrolyte may contain the compound (5) and the compound (11).
• compound (A) contains compound (7).
• the non-aqueous electrolyte may contain compound (7) and compound (9).
• the non-aqueous electrolyte may contain compound (7) and compound (10).
• the non-aqueous electrolyte may contain compound (7) and compound (11).
• compound (A) contains compound (8).
• the non-aqueous electrolyte may contain compound (8) and compound (9).
• the non-aqueous electrolyte may contain compound (8) and compound (10).
• the non-aqueous electrolyte may contain compound (8) and compound (11).
• the nonaqueous electrolyte may contain compound (1) and compound (9).
• the non-aqueous electrolyte may contain compound (2) and compound (9).
• the non-aqueous electrolyte may contain compound (3) and compound (9).
• the non-aqueous electrolyte may contain compound (4) and compound (9).
• the non-aqueous electrolyte may contain compound (1) and compound (10).
• the non-aqueous electrolyte may contain compound (2) and compound (10).
• the non-aqueous electrolyte may contain compound (3) and compound (10).
• the non-aqueous electrolyte may contain compound (4) and compound (10).
• the non-aqueous electrolyte generally contains a non-aqueous solvent.
• a non-aqueous solvent various known ones can be appropriately selected.
• the non-aqueous solvent may be one kind or two or more kinds.
• non-aqueous solvent examples include cyclic carbonates, fluorine-containing cyclic carbonates, chain carbonates, fluorine-containing chain carbonates, aliphatic carboxylic acid esters, fluorine-containing aliphatic carboxylic acid esters, ⁇ -lactones, fluorine-containing ⁇ -lactones, cyclic ethers, fluorine-containing cyclic ethers, chain ethers, fluorine-containing chain ethers, nitriles, amides, lactams, nitromethane, nitroethane, sulfolane, trimethyl phosphate, dimethyl sulfoxide, and dimethyl sulfoxide phosphate.
• Examples of cyclic carbonates include ethylene carbonate (EC), propylene carbonate (PC), and butylene carbonate (BC).
• Examples of fluorine-containing cyclic carbonates include fluoroethylene carbonate (FEC).
• Examples of chain carbonates include dimethyl carbonate (DMC), diethyl carbonate (DEC), ethyl methyl carbonate (EMC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), and dipropyl carbonate (DPC).
• aliphatic carboxylate esters examples include methyl formate, methyl acetate, methyl propionate, methyl butyrate, methyl isobutyrate, methyl trimethylbutyrate, ethyl formate, ethyl acetate, ethyl propionate, ethyl butyrate, ethyl isobutyrate, and ethyl trimethylbutyrate.
• ⁇ -lactones include ⁇ -butyrolactone and ⁇ -valerolactone.
• Examples of cyclic ethers include tetrahydrofuran, 2-methyltetrahydrofuran, tetrahydropyran, 1,3-dioxolane, 4-methyl-1,3-dioxolane, 1,3-dioxane, and 1,4-dioxane.
• Examples of chain ethers include 1,2-ethoxyethane (DEE), ethoxymethoxyethane (EME), diethyl ether, 1,2-dimethoxyethane, and 1,2-dibutoxyethane.
• Examples of nitriles include acetonitrile, glutaronitrile, adiponitrile, methoxyacetonitrile, and 3-methoxypropionitrile.
• the amides include, for example, N,N-dimethylformamide.
• Examples of lactams include N-methylpyrrolidinone, N-methyloxazolidinone, and N,N'-dimethylimidazo
• the non-aqueous solvent preferably contains at least one selected from the group consisting of cyclic carbonates, fluorine-containing cyclic carbonates, chain carbonates, and fluorine-containing chain carbonates.
• the total proportion of the cyclic carbonates, fluorine-containing cyclic carbonates, chain carbonates and fluorine-containing chain carbonates is preferably 50 mass% or more and 100 mass% or less, more preferably 60 mass% or more and 100 mass% or less, and even more preferably 80 mass% or more and 100 mass% or less, based on the total amount of the non-aqueous solvent.
• the non-aqueous solvent preferably contains at least one selected from the group consisting of cyclic carbonates and chain carbonates.
• the total proportion of cyclic carbonates and chain carbonates in the nonaqueous solvent is preferably 50% by mass or more and 100% by mass or less, more preferably 60% by mass or more and 100% by mass or less, and even more preferably 80% by mass or more and 100% by mass or less, based on the total amount of the nonaqueous solvent.
• the lower limit of the content of the nonaqueous solvent is preferably 60 mass % or more, and more preferably 70 mass % or more, based on the total amount of the nonaqueous electrolyte.
• the upper limit of the content of the nonaqueous solvent is preferably 99 mass %, more preferably 97 mass %, and further preferably 90 mass %, based on the total amount of the nonaqueous electrolyte.
• the non-aqueous electrolyte generally contains an electrolyte.
• the electrolyte preferably contains at least one of a fluorine-containing lithium salt (hereinafter sometimes referred to as a "fluorine-containing lithium salt”) and a fluorine-free lithium salt.
• a fluorine-containing lithium salt hereinafter sometimes referred to as a "fluorine-containing lithium salt”
• fluorine-free lithium salt a fluorine-free lithium salt
• Examples of the fluorine-containing lithium salt include inorganic acid anion salts and organic acid anion salts.
• inorganic acid anion salts include lithium hexafluorophosphate (LiPF 6 ), lithium tetrafluoroborate (LiBF 4 ), lithium hexafluoroarsenate (LiAsF 6 ), and lithium hexafluorotantalate (LiTaF 6 ).
• organic acid anion salts examples include lithium trifluoromethanesulfonate (LiCF 3 SO 3 ), lithium bis(trifluoromethanesulfonyl)imide (Li(CF 3 SO 2 ) 2 N), and lithium bis(pentafluoroethanesulfonyl)imide (Li(C 2 F 5 SO 2 ) 2 N).
• lithium hexafluorophosphate (LiPF 6 ) is more preferable as the fluorine-containing lithium salt.
• fluorine-free lithium salts examples include lithium perchlorate (LiClO 4 ), lithium aluminum tetrachloride (LiAlCl 4 ), and lithium decachlorodecaborate (Li 2 B 10 Cl 10 ).
• the content of the fluorine-containing lithium salt is preferably 50 mass % or more and 100 mass % or less, more preferably 60 mass % or more and 100 mass % or less, and even more preferably 80 mass % or more and 100 mass % or less, based on the total amount of the electrolyte.
• the fluorine-containing lithium salt contains lithium hexafluorophosphate (LiPF 6 )
• the content of lithium hexafluorophosphate (LiPF 6 ) is preferably 50 mass % or more and 100 mass % or less, more preferably 60 mass % or more and 100 mass % or less, and even more preferably 80 mass % or more and 100 mass % or less, based on the total amount of the electrolyte.
• the concentration of the electrolyte in the non-aqueous electrolyte is preferably 0.1 mol/L or more and 3 mol/L or less, more preferably 0.2 mol/L or more and 2 mol/L or less, and even more preferably 0.5 mol/L or more and 2 mol/L or less.
• the concentration of lithium hexafluorophosphate (LiPF 6 ) in the non-aqueous electrolyte is preferably 0.1 mol/L or more and 3 mol/L or less, more preferably 0.2 mol/L or more and 2 mol/L or less, and even more preferably 0.5 mol/L or more and 2 mol/L or less.
• the non-aqueous electrolyte may contain other components as necessary.
• Other components include acid anhydrides.
• the lithium secondary battery precursor of the present disclosure is Case and A positive electrode, a negative electrode, a separator, and an electrolyte solution, all of which are housed in a case; Equipped with.
• the positive electrode contains a positive electrode active material containing lithium metal phosphate.
• the electrolyte is a non-aqueous electrolyte of the present disclosure.
• a lithium secondary battery precursor refers to a lithium secondary battery before it is charged and discharged.
• the lithium secondary battery precursor of the present disclosure it is possible to manufacture a lithium secondary battery having an improved capacity retention rate after high-temperature storage or reduced resistance in a region where the SOC is at or below a medium level. Such an effect is brought about by the combination of compound (A) and compound (B) in the nonaqueous electrolyte.
• the shape of the case is not particularly limited and may be appropriately selected depending on the application of the lithium secondary battery precursor of the present disclosure.
• Examples of the case include a case including a laminate film, and a case consisting of a battery can and a battery can lid.
• the positive electrode preferably comprises a positive electrode active material.
• the positive electrode active material is transition metal oxides or sulfides such as MoS2 , TiS2 , MnO2 , V2O5 ; LiCoO 2 , LiMnO 2 , LiMn 2 O 4 , LiNiO 2 , LiNi x Co (1-X) O 2 (0 ⁇ x ⁇ 1), LiNi x Co y Mn z O 2 (x, y and z are each independently greater than 0 and less than 1.00, and the sum of x, y and z is 0.99 to 1.00) (so-called "NCM"; e.g., LiNi 0.33 Co 0.33 Mn 0.33 O 2 , LiNi 0.5 Co 0.3 Mn 0.2 O 2 , LiNi 0.5 Co 0.2 Mn 0.3 O 2 , LiNi 0.6 Co 0.2 Mn composite oxides of lithium and transition metals , such as LiNi0.2O2
• the positive electrode active material preferably contains lithium metal phosphate.
• the nonaqueous electrolyte of the present disclosure can improve the capacity retention rate after high-temperature storage or reduce the resistance of the battery in the region where the SOC is medium or lower, and is particularly excellent in improving the capacity retention rate during storage of a battery containing a positive electrode active material containing lithium metal phosphate (e.g., lithium iron phosphate).
• a positive electrode active material containing lithium metal phosphate e.g., lithium iron phosphate.
• metal is dissolved from the lithium metal phosphate as the positive electrode active material during storage of the battery and precipitates on the negative electrode.
• the nonaqueous electrolyte of the present disclosure can improve the capacity retention rate during storage of a battery containing a positive electrode active material containing lithium metal phosphate (e.g., lithium iron phosphate).
• a positive electrode active material containing lithium metal phosphate e.g., lithium iron phosphate.
• the reason why such an effect is achieved is not clear, but is presumed to be as follows.
• One of the causes of the decrease in the capacity retention rate during storage in the lithium secondary battery is that metal is dissolved from the positive electrode active material containing lithium metal phosphate during storage of the battery and precipitates on the negative electrode.
• lithium metal phosphate examples include lithium iron phosphate (LiFePO 4 ), lithium manganese phosphate (LiMnPO 4 ), lithium manganese iron phosphate (LiMn x Fe 1-x PO 4 ; 0 ⁇ x ⁇ 1), lithium cobalt phosphate (LiCoPO 4 ), and lithium nickel phosphate (LiNiPO 4 ).
• the positive electrode active material preferably contains lithium iron phosphate.
• the positive electrode active material may contain components other than lithium metal phosphate.
• Ingredients other than lithium metal phosphate include: transition metal oxides or sulfides such as MoS2 , TiS2 , MnO2 , V2O5 ; LiCoO 2 , LiMnO 2 , LiMn 2 O 4 , LiNiO 2 , LiNi x Co (1-X) O 2 [0 ⁇ x ⁇ 1], LiNi x Co y Mn z O 2 [x, y and z are each independently greater than 0 and less than 1.00, and the sum of x, y and z is 0.99 to 1.00.
• Lithium and transition metal composite oxides such as LiNi0.33Co0.33Mn0.33O2 , LiNi0.5Co0.3Mn0.2O2 , LiNi0.5Co0.2Mn0.3O2 , LiNi0.6Co0.2Mn0.2O2 , LiNi0.8Co0.1Mn0.1O2 , etc.
• composite oxides consisting of lithium, a transition metal, and a typical metal, such as Li t Ni 1-x-y Co x Al y O 2 (t is 0.95 or more and 1.15 or less, x is 0 or more and 0.3 or less, y is 0.01 or more and 0.2 or less, and the sum of x and y is less than 0.5) (so-called "NCA"; for example, LiNi 0.8 Co 0.15 Al 0.05 O 2 ); Conductive polymer materials such as polyaniline, polythiophene, polypyrrole, polyacetylene, polyacene, dimercaptothiadiazole, and polyaniline composites; etc.
• a typical metal such as Li t Ni 1-x-y Co x Al y O 2 (t is 0.95 or more and 1.15 or less, x is 0 or more and 0.3 or less, y is 0.01 or more and 0.2 or less, and the sum of x and y is less than 0.5) (so-called "
• the proportion of lithium metal phosphate in the positive electrode active material is preferably 70 mass % or more, more preferably 80 mass % or more, and even more preferably 90 mass % or more.
• the proportion of lithium metal phosphate in the positive electrode active material may be 100% by mass or less than 100% by mass.
• the proportion of lithium iron phosphate in the positive electrode active material is preferably 70 mass % or more, more preferably 80 mass % or more, and even more preferably 90 mass % or more.
• the proportion of lithium iron phosphate in the positive electrode active material may be 100 mass % or less than 100 mass %.
• the positive electrode preferably comprises a positive electrode mixture layer containing a positive electrode active material.
• the positive electrode mixture layer may contain components other than the positive electrode active material.
• the components other than the positive electrode active material include a conductive assistant and a binder.
• the conductive assistant include carbon materials such as carbon black (for example, acetylene black), amorphous whiskers, and graphite.
• the binder may be polyvinylidene fluoride or the like.
• the positive electrode mixture layer can be formed by applying a positive electrode mixture slurry containing a positive electrode active material and a solvent onto a positive electrode current collector, which will be described later, and drying the slurry.
• the positive electrode mixture slurry may contain components other than the positive electrode active material (for example, a conductive assistant, a binder, etc.).
• the solvent in the positive electrode mixture slurry may be, for example, an organic solvent such as N-methylpyrrolidone.
• the proportion of the positive electrode active material in the total solid content of the positive electrode mixture layer is preferably 70 mass % or more, more preferably 80 mass % or more, and even more preferably 90 mass % or more.
• the proportion of the positive electrode active material in the total solid content of the positive electrode mixture layer may be 100 mass %.
• the total solid content of the positive electrode mixture layer means the total amount excluding the solvent from the positive electrode mixture layer when the solvent remains in the positive electrode mixture layer, and means the total amount of the positive electrode mixture layer when no solvent remains in the positive electrode mixture layer.
• the proportion of lithium metal phosphate in the total solid content of the positive electrode mixture layer is preferably 70 mass % or more, more preferably 80 mass % or more, and even more preferably 90 mass % or more.
• the proportion of lithium metal phosphate in the total solid content of the positive electrode mixture layer may be 100 mass % or less than 100 mass %.
• the proportion of lithium iron phosphate in the total solid content of the positive electrode mixture layer is preferably 70 mass % or more, more preferably 80 mass % or more, and even more preferably 90 mass % or more.
• the proportion of lithium iron phosphate in the total solid content of the positive electrode mixture layer may be 100 mass % or less than 100 mass %.
• the positive electrode preferably includes a positive electrode current collector.
• a positive electrode current collector There is no particular limitation on the material of the positive electrode current collector, and any known material can be used. Specific examples of the positive electrode current collector include metal materials such as aluminum, aluminum alloys, stainless steel, nickel, titanium, and tantalum; carbon materials such as carbon cloth and carbon paper; and the like.
• the negative electrode preferably includes a negative electrode active material.
• the negative electrode active material for example, at least one selected from the group consisting of metallic lithium, lithium-containing alloys, metals or alloys capable of being alloyed with lithium, oxides capable of being doped/dedoped with lithium ions, transition metal nitrides capable of being doped/dedoped with lithium ions, and carbon materials capable of being doped/dedoped with lithium ions can be used.
• metals or alloys that can be alloyed with lithium (or lithium ions) include silicon, silicon alloys, tin, and tin alloys.
• the negative electrode active material also includes lithium titanate.
• carbon materials capable of being doped and dedoped with lithium ions are preferable.
• examples of such carbon materials include carbon black, activated carbon, graphite materials (artificial graphite, natural graphite), amorphous carbon materials, etc.
• the form of the carbon material may be any of fibrous, spherical, potato-like, and flake-like forms.
• amorphous carbon material examples include hard carbon, coke, mesocarbon microbeads (MCMB) calcined at 1500° C. or less, and mesophase pitch carbon fiber (MCF).
• examples of the graphite material include natural graphite and artificial graphite.
• examples of the artificial graphite include graphitized MCMB and graphitized MCF.
• Examples of the graphite material that can be used include those containing boron.
• Examples of the graphite material that can be used include those coated with metals such as gold, platinum, silver, copper, and tin, those coated with amorphous carbon, and those mixed with amorphous carbon and graphite.
• carbon materials may be used alone or in combination of two or more.
• a carbon material having a lattice spacing d(002) of 0.340 nm or less as measured by X-ray analysis is particularly preferred.
• graphite having a true density of 1.70 g/cm 3 or more or a highly crystalline carbon material having properties similar thereto is also preferred. By using such carbon materials, the energy density of the battery can be increased.
• the proportion of the carbon material (preferably graphite material) in the negative electrode active material is preferably 70 mass % or more, more preferably 80 mass % or more, and further preferably 90 mass % or more.
• the proportion of the carbon material (preferably the graphite material) in the negative electrode active material may be 100% by mass or less than 100% by mass.
• the negative electrode preferably includes a negative electrode mixture layer containing a negative electrode active material.
• the negative electrode mixture layer may contain components other than the negative electrode active material.
• components other than the negative electrode active material include a conductive assistant and a binder.
• the conductive assistant include the same conductive assistants as those exemplified as the conductive assistants that can be contained in the positive electrode mixture layer.
• the binder include carboxymethyl cellulose and SBR latex.
• the negative electrode mixture layer can be formed by applying a negative electrode mixture slurry containing a negative electrode active material and a solvent onto a negative electrode current collector described below, and drying the slurry.
• the negative electrode mixture slurry may contain components other than the negative electrode active material (for example, a conductive assistant, a binder, etc.).
• An example of the solvent in the negative electrode mixture slurry is water.
• the proportion of the negative electrode active material in the total solid content of the negative electrode mixture layer is preferably 70 mass % or more, more preferably 80 mass % or more, and even more preferably 90 mass % or more.
• the proportion of the negative electrode active material in the total solid content of the negative electrode mixture layer may be 100 mass %.
• the total solid content of the negative electrode mixture layer means the total amount excluding the solvent from the negative electrode mixture layer when the solvent remains in the negative electrode mixture layer, and means the total amount of the negative electrode mixture layer when no solvent remains in the negative electrode mixture layer.
• the proportion of the carbon material (preferably graphite material) in the total solid content of the negative electrode mixture layer is preferably 70 mass % or more, more preferably 80 mass % or more, and even more preferably 90 mass % or more.
• the proportion of the carbon material (preferably the graphite material) in the total solid content of the negative electrode mixture layer may be 100 mass %.
• the negative electrode preferably includes a negative electrode current collector.
• the material of the negative electrode current collector is not particularly limited, and any known material can be used.
• Specific examples of the negative electrode current collector include metal materials such as copper, nickel, stainless steel, nickel-plated steel, etc. Among these, copper is particularly preferred from the viewpoint of ease of processing.
• the separator may be, for example, a porous resin plate.
• the material of the porous resin plate may be a resin, a nonwoven fabric containing the resin, etc.
• the resin may be polyethylene (PE), polypropylene (PP), polymethylpentene (PMP), polyester, cellulose, polyamide, etc.
• the separator is preferably a porous resin sheet having a single layer or a multilayer structure.
• the material of the porous resin sheet is mainly composed of one or more polyolefin resins.
• the thickness of the separator is preferably 5 ⁇ m or more and 30 ⁇ m or less.
• the separator is preferably disposed between the positive electrode and the negative electrode.
• FIG. 1 is a schematic cross-sectional view showing a laminated type lithium secondary battery precursor, which is an example of a lithium secondary battery precursor according to the present disclosure.
• a lithium secondary battery precursor 1 is a laminated type battery precursor. Specifically, in the lithium secondary battery precursor 1, the battery element 10 is enclosed inside an exterior body 30.
• the exterior body 30 is formed of a laminate film.
• a positive electrode lead 21 and a negative electrode lead 22 are each attached to the battery element 10.
• the positive electrode lead 21 and the negative electrode lead 22 are each led out in opposite directions from the inside to the outside of the exterior body 30.
• the battery element 10 is formed by stacking a positive electrode 11, a separator 13, and a negative electrode 12.
• the positive electrode 11 is formed by forming a positive electrode composite layer 11B on both main surfaces of a positive electrode collector 11A.
• the negative electrode 12 is formed by forming a negative electrode composite layer 12B on both main surfaces of a negative electrode collector 12A.
• the positive electrode composite layer 11B formed on one main surface of the positive electrode collector 11A of the positive electrode 11 and the negative electrode composite layer 12B formed on one main surface of the negative electrode collector 12A of the negative electrode 12 adjacent to the positive electrode 11 face each other via the separator 13.
• the nonaqueous electrolyte of the present disclosure is injected into the interior of the exterior body 30 of the lithium secondary battery precursor 1.
• the nonaqueous electrolyte of the present disclosure permeates the positive electrode composite layer 11B, the separator 13, and the negative electrode composite layer 12B.
• one single cell layer 14 is formed by the adjacent positive electrode composite layer 11B, the separator 13, and the negative electrode composite layer 12B.
• the positive electrode and the negative electrode may each have a composite layer formed on one side of each current collector.
• the lithium secondary battery precursor 1 is a laminated type lithium secondary battery precursor, but the lithium secondary battery precursor of the present disclosure is not limited to this and may be, for example, a wound type lithium secondary battery precursor.
• a wound type lithium secondary battery precursor is formed by stacking a positive electrode, a separator, a negative electrode, and a separator in this order and winding them into layers.
• Wound type lithium secondary battery precursors include cylindrical lithium secondary battery precursors and prismatic lithium secondary battery precursors.
• the directions in which the positive electrode lead and the negative electrode lead each protrude from the inside of the exterior body 30 to the outside are opposite directions relative to the exterior body 30, but the present disclosure is not limited to this.
• the directions in which the positive electrode lead and the negative electrode lead each protrude from the inside of the exterior body 30 to the outside may be in the same direction relative to the exterior body 30.
• An example of the lithium secondary battery of the present disclosure described below is a lithium secondary battery obtained by charging and discharging the lithium secondary battery precursor 1.
• FIG. 2 is a schematic cross-sectional view showing a coin-type lithium secondary battery precursor, which is another example of a lithium secondary battery precursor according to the present disclosure.
• a disk-shaped negative electrode 42, a separator 45 filled with a nonaqueous electrolyte, a disk-shaped positive electrode 41, and, if necessary, spacer plates 47, 48 made of stainless steel, aluminum, or the like are stacked in this order and housed between a positive electrode can 43 (hereinafter also referred to as a "battery can") and a sealing plate 44 (hereinafter also referred to as a “battery can lid").
• the positive electrode can 43 and the sealing plate 44 are crimped and sealed via a gasket 46.
• the nonaqueous electrolyte of the present disclosure is used as the nonaqueous electrolyte injected into separator 45 .
• An example of the lithium secondary battery of the present disclosure described below is a lithium secondary battery obtained by charging and discharging the coin-type lithium secondary battery precursor shown in FIG. 2.
• the method for producing a lithium secondary battery according to the present disclosure includes: A step of preparing the lithium secondary battery precursor of the present disclosure described above (hereinafter also referred to as a "preparation step”); charging and discharging the lithium secondary battery precursor; Includes.
• the lithium secondary battery of the present disclosure is a lithium secondary battery obtained by charging and discharging the above-mentioned lithium secondary battery precursor of the present disclosure.
• the lithium secondary battery and manufacturing method thereof disclosed herein can improve the capacity retention rate of the lithium secondary battery during storage.
• the preparation step may be a step of simply preparing a previously manufactured lithium secondary battery precursor of the present disclosure for a step of charging and discharging, or may be a step of manufacturing a lithium secondary battery precursor of the present disclosure.
• the lithium secondary battery precursor is as described above.
• the lithium secondary battery precursor can be charged and discharged according to a known method.
• the lithium secondary battery precursor may be subjected to a cycle of charging and discharging multiple times.
• this charging and discharging preferably forms a SEI (Solid Electrolyte Interface) film on the surface of the positive electrode (particularly the positive electrode active material) and/or the negative electrode (particularly the negative electrode active material) in the lithium secondary battery precursor.
• SEI Solid Electrolyte Interface
• the charging and discharging process preferably involves subjecting the lithium secondary battery precursor to a combination of charging and discharging at least once in an environment of 25°C to 70°C.
• Example 1-1 Preparation of non-aqueous electrolyte> Ethylene carbonate (hereinafter, “EC”), dimethyl carbonate (hereinafter, “DMC”), and ethyl methyl carbonate (hereinafter, “EMC”) were mixed.
• the volume ratio (EC:DMC:EMC) was 30:35:35.
• a mixed solvent was obtained as a non-aqueous solvent.
• LiPF6 as an electrolyte was dissolved so that the concentration in the finally obtained nonaqueous electrolyte solution was 1.2 mol/L, to obtain an electrolyte solution (hereinafter also referred to as “basic electrolyte solution”).
• Graphite (96% by mass) as a negative electrode active material, carbon black (1% by mass) as a conductive assistant, 1% by mass in terms of solid content of sodium carboxymethylcellulose dispersed in pure water as a thickener, and 2% by mass in terms of solid content of styrene-butadiene rubber (SBR) dispersed in pure water as a binder were mixed together to obtain a negative electrode mixture slurry.
• a copper foil having a thickness of 10 ⁇ m was prepared as a negative electrode current collector.
• the obtained negative electrode mixture slurry was applied onto a copper foil, dried, and then rolled with a press to obtain a sheet-shaped negative electrode.
• the negative electrode was composed of a negative electrode current collector and a negative electrode mixture layer.
• the negative electrode was punched out into a disk shape with a diameter of 14 mm.
• the positive electrode was punched out into a disk shape with a diameter of 13 mm.
• the separator was punched out into a disk shape with a diameter of 17 mm.
• a coin-shaped negative electrode, a coin-shaped positive electrode, and a coin-shaped separator were obtained.
• the obtained coin-shaped negative electrode, coin-shaped separator, and coin-shaped positive electrode were stacked in this order in a stainless steel battery can (size: 2032 size).
• a coin-type lithium secondary battery precursor i.e., a lithium secondary battery before being charged and discharged
• the lithium secondary battery precursor had a diameter of 20 mm and a height of 3.2 mm.
• the lithium secondary battery precursor was charged to 4.2 V and discharged to 2.5 V three times in a temperature range of 25° C. to 70° C. to obtain a lithium secondary battery.
• Example 1-1 A nonaqueous electrolyte was obtained in the same manner as in Example 1-1, except that the type and content of the additive in the nonaqueous electrolyte were changed as shown in Table 1. Using the obtained nonaqueous electrolyte, the battery resistance (SOC 50%) and the battery resistance (SOC 25%) were measured in the same manner as in Example 1-1. The results are shown in Table 1.
• the additives added to the nonaqueous electrolytes of Examples 1-2 to 1-3 and Reference Example 1-1 are as shown in the following formulas, respectively, and compound (6)-1 (i.e., bis(fluorosulfonyl)imide) of Reference Example 1-1 is a specific example of compound (6). Each result is shown as a relative value when the value of Reference Example 1-1 is set to 100.
• the nonaqueous electrolyte solutions for batteries in Examples 1-1 to 1-3 contained compound (A) and compound (B).
• Compound (A) in Examples 1-1 to 1-3 consisted of compound (2) and compound (3).
• Compound (B) in Examples 1-1 to 1-3 consisted of compound (9).
• the nonaqueous electrolyte solution for batteries in Reference Example 1-1 contained compound (A) but did not contain compound (B). Therefore, in the region where the SOC was moderate or lower (specifically, SOC 50% and SOC 25%), the battery resistances of Examples 1-1 to 1-3 were reduced compared to Reference Example 1-1.
• Examples 2-1 to 2-17, Comparative Example 2-1] Preparation of non-aqueous electrolyte> A nonaqueous electrolyte solution was obtained in the same manner as in Example 1-1, except that the type and content of the additive in the nonaqueous electrolyte solution were changed as shown in Table 2.
• the lithium secondary battery was charged to 3.5 V at a charge rate of 0.2 C in a thermostatic chamber at 25° C. using CC-CV (Constant Current-Constant Voltage), and then the initial (i.e., before high-temperature storage) discharge capacity (0.2 C) (mAh) was measured at 25° C. and a discharge rate of 0.2 C.
• CC-CV Constant Current-Constant Voltage
• the lithium secondary battery whose initial discharge capacity (0.2 C) had been measured was CC-CV charged to 4.2 V at a charge rate of 0.2 C at 25° C., and then stored in a temperature environment of 60° C. (hereinafter referred to as "high temperature storage"). The storage time of this high temperature storage will be described later.
• the recovered discharge capacity after high-temperature storage was measured as follows.
• the lithium secondary battery after high-temperature storage was CC-discharged at a discharge rate of 0.2 C at 25° C. until the SOC became 0%, and then CC-CV charged at a charge rate of 0.2 C to 4.2 V.
• this lithium secondary battery was CC-discharged at a discharge rate of 0.2 C, and the recovered discharge capacity (0.2 C) (mAh) after high-temperature storage was measured.
• the nonaqueous electrolytes of Examples 2-1 to 2-17 contained compound (A) and compound (B).
• Compound (A) of Examples 2-1 to 2-17 was at least one selected from the group consisting of compound (1), compound (2), compound (3), compound (4), compound (5), compound (6), compound (7), and compound (8).
• Compound (B) of Examples 2-1 to 2-17 consisted of compound (9).
• the nonaqueous electrolyte of Comparative Example 2-1 contained compound (B) and did not contain compound (A).
• Compound (B) of Comparative Example 2-1 consisted of compound (9).
• Examples 2-1 to 2-17 were improved compared to Comparative Example 2-1, and the battery resistances of Examples 2-1 to 2-17 were reduced compared to Comparative Example 2-1 in the medium or lower SOC range (specifically, SOC 50% (25°C) and SOC 50% (-10°C)).
• Example 3-1 Preparation of non-aqueous electrolyte>
• ethylene carbonate (EC), dimethyl carbonate (DMC), and methyl ethyl carbonate (EMC) were mixed to obtain a mixed solvent with a volume ratio (EC:DMC:EMC) of 20:35:45.
• LiPF 6 was dissolved as an electrolyte so that the electrolyte concentration in the finally prepared nonaqueous electrolyte solution was 0.9 mol/L.
• additives were added as follows to obtain a non-aqueous electrolyte solution.
• the above-mentioned compound (9)-1 which is a specific example of the compound (9), was added so that the content thereof was 1.0% by mass relative to the total mass of the nonaqueous electrolyte solution. Furthermore, the above-mentioned compound (1)-1, which is a specific example of compound (1), was added so that the content thereof was 0.5% by mass relative to the total mass of the nonaqueous electrolyte solution.
• Lithium iron phosphate (LiFePO 4 ; hereinafter also referred to as “LFP”) (90 parts by mass) as a positive electrode active material, acetylene black (5 parts by mass) as a conductive assistant, and polyvinylidene fluoride (5 parts by mass) as a binder were kneaded using N-methylpyrrolidinone as a solvent to prepare a paste-like positive electrode composite slurry.
• the positive electrode mixture slurry was applied to a positive electrode current collector made of a strip of aluminum foil having a thickness of 20 ⁇ m, dried, and then compressed by a roll press to obtain a sheet-like positive electrode consisting of the positive electrode current collector and a positive electrode mixture layer.
• the coating density of the positive electrode mixture layer at this time was 12 mg/ cm2 , and the filling density was 2.0 g/mL.
• Natural graphite (98 parts by mass) as a negative electrode active material, carboxymethyl cellulose (1 part by mass) as a binder, and SBR latex (1 part by mass) as a binder were kneaded with an aqueous solvent to prepare a paste-like negative electrode mixture slurry.
• the negative electrode composite slurry was applied to a negative electrode current collector made of a strip of copper foil having a thickness of 10 ⁇ m, dried, and then compressed by a roll press to obtain a sheet-like negative electrode consisting of the negative electrode current collector and a negative electrode composite layer.
• the coating density of the negative electrode composite layer at this time was 6.0 mg/ cm2 , and the filling density was 1.5 g/mL.
• a microporous polyethylene film having a thickness of 20 ⁇ m was prepared.
• the negative electrode was punched out into a disk shape with a diameter of 14 mm.
• the positive electrode was punched out into a disk shape with a diameter of 13 mm.
• a coin-shaped negative electrode and a coin-shaped positive electrode were obtained.
• the separator was punched out into a disk shape with a diameter of 17 mm to obtain a coin-shaped separator.
• the obtained coin-shaped negative electrode, coin-shaped separator, and coin-shaped positive electrode were stacked in this order in a stainless steel battery can (size 2032).
• 18 ⁇ L of non-aqueous electrolyte was poured into the battery can to impregnate the separator, positive electrode, and negative electrode.
• a coin-type lithium secondary battery precursor i.e., a lithium secondary battery before being charged and discharged
• the lithium secondary battery precursor had a diameter of 20 mm and a height of 3.2 mm.
• the lithium secondary battery was charged to 3.5 V at a charge rate of 0.2 C in a thermostatic chamber at 25° C. by CC-CV (Constant Current - Constant Voltage), and then the initial (i.e., before high-temperature storage) discharge capacity (0.2 C) (mAh) was measured at 25° C. and a discharge rate of 0.2 C.
• CC-CV Constant Current - Constant Voltage
• the lithium secondary battery whose initial discharge capacity (0.2 C) had been measured was CC-CV charged to 3.5 V at a charge rate of 0.2 C at 25° C., and then stored in a temperature environment of 60° C. (hereinafter referred to as "high temperature storage"). The storage time of this high temperature storage will be described later.
• the recovered discharge capacity after high-temperature storage was measured as follows.
• the lithium secondary battery after high-temperature storage was CC-discharged at a discharge rate of 0.2 C at 25° C. until the SOC (State of charge) became 0%, and then CC-CV charged to 3.5 V at a charge rate of 0.2 C.
• this lithium secondary battery was CC-discharged at a discharge rate of 0.2 C, and the recovered discharge capacity (0.2 C) (mAh) after high-temperature storage was measured.
• Capacity retention rate during storage [(recovered discharge capacity after high-temperature storage (0.2C))/(initial discharge capacity (0.2C)] x 100
• Examples 3-2 to 3-14, Comparative Examples 3-1 to 3-3 A nonaqueous electrolyte solution was obtained in the same manner as in Example 3-1, except that the type and content of the additives used in the preparation of the nonaqueous electrolyte solution were changed as shown in Table 3. Using the obtained nonaqueous electrolyte solution, the initial capacity retention rate, the capacity retention rate during storage 7 days after the start of high-temperature storage, and the capacity retention rate during storage 14 days after the start of high-temperature storage were measured in the same manner as in Example 3-1. The results are shown in Table 3. The additives added to the nonaqueous electrolytes of Examples 3-1 to 3-14 and Comparative Examples 3-1 to 3-3 are as shown below. In Table 3, "-" means that no additive was added.
• the nonaqueous electrolytes of Examples 3-2 to 3-14 contained the compound (A) and the compound (B).
• the nonaqueous electrolytes of Comparative Examples 3-1 to 3-3 contained the compound (B) but did not contain the compound (A). Therefore, the capacity retention rates during storage of the batteries of Examples 3-1 to 3-14 were superior to those of Comparative Examples 3-1 to 3-3.
• the compound (A) in Examples 3-8 to 3-12 consisted of at least one selected from the group consisting of compound (1), compound (2), compound (3), compound (4), and compound (5).
• the compound (A) in Examples 3-1 to 3-7 consisted of only one compound. Therefore, the capacity retention rate during storage of the batteries in Examples 3-8 to 3-12 was superior to that of Examples 3-1 to 3-7.
• Examples 3-15 to 3-19, Comparative Example 3-4 The same operations as in Example 3-1 were performed except that the type and content of the additives used in the preparation of the nonaqueous electrolyte were changed as shown in Table 4, and further, the lithium ion secondary battery precursor was produced as follows. The results are shown in Table 4.
• the additives added to the nonaqueous electrolytes of Examples 3-1 to 3-19 and Comparative Example 3-4 are as shown in the following formulas. In Table 4, "-" means that no additive was added.
• a sheet-shaped negative electrode similar to the sheet-shaped negative electrode in Example 3-1 was prepared, and a sheet-shaped positive electrode similar to the sheet-shaped positive electrode in Example 3-1 was prepared.
• the sheet-like negative electrode was punched out into a rectangular shape of 42 mm in length and 31 mm in width.
• the sheet-like positive electrode was punched out into a rectangular shape of 40 mm in length and 29 mm in width.
• a rectangular negative electrode and a rectangular positive electrode were obtained.
• the separator was punched out into a rectangular shape of 45 mm in length and 35 mm in width to obtain a rectangular separator.
• the rectangular negative electrode, the rectangular separator, and the rectangular positive electrode obtained were stacked in this order in a bag-shaped aluminum laminate, and then 125 ⁇ L of a non-aqueous electrolyte was poured into the aluminum laminate to impregnate the rectangular separator, the rectangular positive electrode, and the rectangular negative electrode.
• the cell was then sealed by closing the opening of the bag with a heat sealer.
• a laminated lithium secondary battery precursor having the structure shown in FIG. 1 (that is, a lithium secondary battery before being charged and discharged) was obtained.
• the nonaqueous electrolytes of Examples 3-15 to 3-19 contained the compound (A) and the compound (B).
• the nonaqueous electrolyte of Comparative Example 3-4 contained the compound (B) but did not contain the compound (A). Therefore, the capacity retention rates during storage of the batteries of Examples 3-15 to 3-19 were superior to that of Comparative Example 4.
• the compound (B) in Examples 3-16 to 3-19 consisted of at least one selected from the group consisting of the compound (6), the compound (7), and the compound (8).
• the compound (B) in Example 3-15 consisted of one compound. Therefore, the capacity retention rates during storage of the batteries in Examples 3-16 to 3-19 were superior to that of Example 3-15.

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