WO2016117280A1 - 非水系電解液及びそれを用いた非水系電解液電池 - Google Patents
非水系電解液及びそれを用いた非水系電解液電池 Download PDFInfo
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- WO2016117280A1 WO2016117280A1 PCT/JP2015/086564 JP2015086564W WO2016117280A1 WO 2016117280 A1 WO2016117280 A1 WO 2016117280A1 JP 2015086564 W JP2015086564 W JP 2015086564W WO 2016117280 A1 WO2016117280 A1 WO 2016117280A1
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- H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
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- H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
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- H01M4/583—Carbonaceous material, e.g. graphite-intercalation compounds or CFx
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- H01M2300/0037—Mixture of solvents
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- 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
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- 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
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- Y02T10/00—Road transport of goods or passengers
- Y02T10/60—Other road transportation technologies with climate change mitigation effect
- Y02T10/70—Energy storage systems for electromobility, e.g. batteries
Definitions
- the present invention relates to a non-aqueous electrolyte having excellent output characteristics at low temperatures and a battery using a non-aqueous electrolyte such as a lithium secondary battery using the non-aqueous electrolyte. Furthermore, the present invention relates to an additive useful as an additive for a non-aqueous electrolyte solution.
- Non-aqueous electrolyte batteries such as lithium ion batteries, lithium batteries, and lithium ion capacitors have been actively developed as candidates for these various power storage systems.
- a lithium secondary battery is mainly composed of a positive electrode, a non-aqueous electrolyte, and a negative electrode.
- the negative electrode constituting the lithium secondary battery for example, metal lithium, metal compounds capable of occluding and releasing lithium (for example, simple metals, oxides, alloys with lithium, etc.), carbon materials, etc. are known.
- Lithium secondary batteries using carbon materials such as coke, artificial graphite, and natural graphite that can occlude and release are widely put into practical use.
- a lithium secondary battery using a highly crystallized carbon material such as natural graphite or artificial graphite as a negative electrode material is generated due to reduction and decomposition of the nonaqueous solvent in the nonaqueous electrolyte solution on the negative electrode surface during charging. It has been reported that the decomposed product and gas inhibit the original electrochemical reaction of the battery, so that the cycle characteristics are deteriorated.
- lithium secondary batteries using lithium metal, its alloys, simple metals such as silicon and tin, and oxides as negative electrode materials have high initial capacity, but the negative electrode materials are becoming finer during the cycle.
- non-aqueous solvents are more likely to undergo reductive decomposition.
- the first cycle charge / discharge efficiency decreases as the initial irreversible capacity of the battery increases, and the battery performance such as the battery capacity and cycle characteristics associated therewith decreases. It is known that it decreases greatly.
- the negative electrode and the lithium cation, or the negative electrode and the electrolyte solvent react with each other, and the coating mainly contains lithium oxide, lithium carbonate, or alkyl lithium carbonate on the negative electrode surface.
- the coating on the electrode surface is called Solid Electrolyte Interface (SEI), and its properties have a great influence on the battery performance, such as suppressing the reductive decomposition of the solvent and suppressing the deterioration of the battery performance.
- SEI Solid Electrolyte Interface
- the positive electrode for example LiCoO 2, LiMn 2 O 4, LiNiO 2, LiFePO 4 , etc. are known.
- the non-aqueous solvent in the non-aqueous electrolyte solution is partially oxidized and decomposed locally at the interface between the positive electrode material and the non-aqueous electrolyte solution.
- decomposition products and gases generated thereby inhibit the battery's original electrochemical reaction, resulting in deterioration of battery performance such as cycle characteristics.
- a film made of an oxidative decomposition product is formed on the surface of the positive electrode similarly to the negative electrode, and this also plays an important role in suppressing the oxidative decomposition of the solvent and the amount of battery gas generated.
- SEI with high ion conductivity and low electron conductivity is stable over the long term. It is important to form a compound, and an attempt to positively form a good SEI by adding a small amount of compound called an additive to the electrolyte (usually 0.01% by mass or more and 10% by mass or less). Widely made.
- the non-aqueous electrolyte solution is decomposed with a non-aqueous electrolyte solution containing, for example, vinylene carbonate, vinyl ethylene carbonate, maleic anhydride, phthalic anhydride, or the like.
- a non-aqueous electrolyte solution containing, for example, vinylene carbonate, vinyl ethylene carbonate, maleic anhydride, phthalic anhydride, or the like Attempts have been made to improve the storage characteristics and cycle characteristics at high temperatures, storage characteristics at high temperatures, and cycle characteristics (Patent Document 1, Patent Document 2, Patent Document 3, and Patent Document 4). However, the level is still not enough.
- Patent Document 5 discloses a non-aqueous electrolyte battery using an electrolytic solution containing a diisocyanate compound, and attempts have been made to improve the long-term storage reliability of the battery.
- LiPF 6 or LiBF 4 which are general Li salts
- the thermal stability of the electrolyte is improved and the transition contained in the positive electrode active material
- Patent Document 6 A method for improving the life performance by suppressing the generation of hydrofluoric acid causing elution of metal has been studied.
- a lithium salt having an oxalate complex such as lithium bis (oxalato) borate as an anion, and at least one film forming agent selected from the group consisting of vinylene carbonate, vinyl ethylene carbonate, ethylene sulfite, and fluoroethylene carbonate;
- a non-aqueous electrolyte solution containing Pt (Patent Document 7) is disclosed.
- Non-aqueous electrolytes containing phosphorus and boron complexes such as lithium difluorooxalatoborate have been disclosed as additives for forming effective SEI (Patent Document 8), and have excellent regenerative output.
- Patent Document 8 As a means for providing a lithium ion secondary battery that can be shown, a case where a hard carbon negative electrode is used and a battery structure having a predetermined positive electrode / negative electrode capacity ratio and the same phosphorus or boron complex as a non-aqueous electrolyte is contained. (Patent Document 9) is disclosed.
- Patent Documents 10 and 11 proposals for improving input / output characteristics at low temperatures by containing a predetermined amount of vinylene carbonate or fluoroethylene carbonate and lithium difluoro (bisoxalato) phosphate (Patent Documents 10 and 11), difluoro (oxalato-O) , O ′) by using an electrolytic solution containing lithium borate or tetrafluoro (oxalato-O, O ′) lithium phosphate and a carbonate of an unsaturated compound such as vinylene carbonate or vinylethylene carbonate as an additive.
- Patent Document 12 for improving battery characteristics such as battery capacity, cycle characteristics and storage characteristics is disclosed.
- Patent Document 13 discloses a compound in which a triple bond is bonded to a ring structure by a single bond without any other functional group or heteroelement (4-ethynylethylene carbonate, 4-ethynyl-1,3,2-dioxathiolane- 2,2-dioxide, etc.), and compounds such as LiPO 2 F 2 and LiSO 3 F, lithium bis (oxalato) borate, lithium difluorooxalatoborate, lithium tetrafluorofluorooxalate phosphate, lithium difluorobis (oxalato) Cycle, storage by containing at least one of the group consisting of a phosphate, a lithium salt of an oxalato complex such as lithium tris (oxalato) phosphate, a carbon-carbon unsaturated bond, or a carbonate having at least one fluorine atom Durability characteristics and load characteristics such as Describes a proposed improved.
- Patent Document 14 includes a lithium transition metal composite oxide having a layered rock salt structure in a positive electrode, and a nonaqueous solvent containing a fluorinated solvent (such as fluorinated carbonate) in a range of 20 to 100% by volume in the nonaqueous solvent. And at least one compound selected from the group consisting of a compound having a carbon-nitrogen unsaturated bond, a compound having a substituent having a carbon-carbon unsaturated bond, and a compound having a sulfonate structure
- a proposal for improving the discharge capacity, the initial charge / discharge efficiency, and the load characteristics is described.
- Patent Document 15 includes an element capable of alloying with lithium and an element compound capable of alloying with lithium in the negative electrode, the non-aqueous solvent includes fluorine-based ethylene carbonate, and lithium difluorobis ( Oxalato) phosphate, lithium difluorooxalatoborate, lithium tetrafluorooxalatophosphate, and the like have been proposed to improve charge / discharge cycle characteristics.
- Patent Document 16 discloses that both difluoro (bisoxalato) phosphate and tetrafluoro (oxalato) phosphate contain low cycle characteristics ( ⁇ 20 ° C./25° C.) as well as cycle characteristics and high temperature storage characteristics.
- An electrolytic solution capable of improving the discharge capacity ratio is disclosed.
- Patent Document 19 also discloses a method for producing phosphorus and boron complexes including lithium difluorooxalatoborate used as an electrolyte for electrochemical devices.
- Patent Document 17 discloses a method for producing tris (oxalato) lithium phosphate.
- Patent Document 18 shows that when a diisocyanate compound (hexamethylene diisocyanate), which is one of compounds having a carbon-nitrogen unsaturated bond, is added to a non-aqueous electrolyte, cycle characteristics and storage characteristics are improved. Is disclosed.
- hexamethylene diisocyanate hexamethylene diisocyanate
- Non-Patent Document 1 discloses a method for producing a fluoro complex having silicon or the like as a complex center.
- non-aqueous electrolytes such as those described above, as the demand for higher performance of batteries in recent years increases, output characteristics at a low temperature of 0 ° C. or lower, storage characteristics at a high temperature of 60 ° C. or higher, etc. Further improvements were desired.
- many non-aqueous electrolyte batteries mainly lithium-ion batteries, have already been put into practical use, but in more severe conditions such as in-vehicle batteries and stationary batteries used outdoors from mid-winter to mid-summer. In applications that may be used, it could not be said that an electrolytic solution having sufficient characteristics was obtained.
- Patent Document 18 discloses that when a diisocyanate compound is added to a non-aqueous electrolyte, cycle characteristics and storage characteristics are improved, while low-temperature characteristics are lowered, specifically, charge / discharge capacity in a low-temperature environment. It also describes the problem of being reduced.
- the present inventors have made extensive studies on a six-coordinate ionic complex in which cis and trans isomers may exist, and added the cis and trans isomers separately, and the results of comparing the effects It was clarified that the cis body has a higher effect of improving the output characteristics at low temperatures after the cycle endurance test. Furthermore, the present invention includes both the cis hexacoordinate ionic complex and a specific compound, so that even when the battery is used to some extent, it can exhibit high output characteristics at a low temperature of 0 ° C. or lower.
- a non-aqueous electrolyte solution and a non-aqueous electrolyte battery that exhibit a large charge / discharge capacity at a high rate at room temperature and that can also exhibit sufficient performance at a low temperature even after being stored at a high temperature of 60 ° C. or higher Is to provide.
- the present invention provides a nonaqueous electrolytic solution comprising a nonaqueous organic solvent and an electrolyte dissolved in the nonaqueous organic solvent.
- the nonaqueous electrolyte solution characterized by including this is provided.
- a + is any one selected from the group consisting of metal ions, protons and onium ions
- M is any one selected from the group consisting of Si, P, As and Sb.
- F is a fluorine atom
- O is an oxygen atom.
- M is Si
- t is 2.
- X is an oxygen atom or —N (R 1 ) —.
- N is a nitrogen atom
- R 1 is a hydrocarbon group which may have a heteroatom having 1 to 10 carbon atoms or a halogen atom (in the case of 3 or more carbon atoms, it has a branched chain or cyclic structure). Can also be used).
- Y is a carbon atom or a sulfur atom.
- Q is 1 when Y is a carbon atom.
- Q is 1 or 2 when Y is a sulfur atom.
- W is a hydrocarbon group which may have a heteroatom having 1 to 10 carbon atoms or a halogen atom (in the case of 3 or more carbon atoms, a branched chain or cyclic structure can be used), or- N (R 2 ) — is represented.
- R 2 represents a hydrogen atom, an alkali metal, a hydrocarbon group having 1 to 10 carbon atoms or a halogen atom which may have a halogen atom.
- R 2 can take a branched chain or a cyclic structure.
- p represents 0 or 1
- q represents an integer of 0 to 2
- r represents an integer of 0 to 2, respectively.
- the present invention provides a non-aqueous electrolyte battery comprising the above non-aqueous electrolyte, a positive electrode, a negative electrode, and a separator.
- the present invention even in a state where the battery is used to some extent, it can exhibit high output characteristics at a low temperature of 0 ° C. or lower, exhibits a good high rate characteristic, and even after being stored at a high temperature of 60 ° C. or higher, Similarly, a non-aqueous electrolyte solution and a non-aqueous electrolyte battery that can exhibit sufficient performance at low temperatures can be provided.
- Non-aqueous electrolyte includes a non-aqueous organic solvent and an electrolyte dissolved in the non-aqueous organic solvent, and further has a cis-type conformation represented by the general formula (1-Cis). It comprises a complex (1-Cis) and at least one compound selected from the group consisting of the following compounds (II).
- a + is any one selected from the group consisting of metal ions, protons and onium ions
- M is a group consisting of Si, P, As and Sb. Any one selected from F is a fluorine atom, and O is an oxygen atom.
- M Si
- t is 2.
- X is an oxygen atom or —N (R 1 ) —.
- N is a nitrogen atom
- R 1 is a hydrocarbon group which may have a heteroatom having 1 to 10 carbon atoms or a halogen atom (in the case of 3 or more carbon atoms, it has a branched chain or cyclic structure).
- Y is a carbon atom or a sulfur atom.
- Q is 1 when Y is a carbon atom.
- Q is 1 or 2 when Y is a sulfur atom.
- W is a hydrocarbon group which may have a heteroatom having 1 to 10 carbon atoms or a halogen atom (in the case of 3 or more carbon atoms, a branched chain or cyclic structure can be used), or- N (R 2 ) — is represented.
- R 2 represents a hydrogen atom, an alkali metal, a hydrocarbon group having 1 to 10 carbon atoms or a halogen atom which may have a halogen atom.
- R 2 can take a branched chain or a cyclic structure.
- p represents 0 or 1
- q represents an integer of 0 to 2
- r represents an integer of 0 to 2, respectively.
- the difluoroionic complex (1) is a hexacoordinate complex in which a bidentate ligand is coordinated to a central element M by bimolecular coordination, and fluorine (hereinafter F) is coordinated bimolecularly.
- F fluorine
- a complex in which a ligand is coordinated to the central element M (Si, P, As, Sb) via oxygen or nitrogen is stable, and is isomerized by exchange of the ligand in the absence of a catalyst.
- Fluorine is obtained by improving the conditions described in Patent Document 19 and ditrioionic complex (1) obtained after excessive reaction proceeds, or a trimolecular coordination compound synthesized with reference to Patent Document 17
- a cis / trans mixture is obtained.
- a mixed solvent of a carbonate and a chlorinated solvent each of the filtrate side and the mother liquor side
- (1-Cis) and (1-Trans) having a purity of 99.9 mol% or more can be obtained separately.
- each of (1-Cis) and (1-Trans) may be selectively synthesized.
- the purity of each of (1-Cis) and (1-Trans) is preferably 95 mol% or more, more preferably 98 mol% or more, and even more preferably 99 mol% or more.
- the difluoroionic complex added to the nonaqueous electrolyte battery electrolyte of the present invention is not a cis / trans equivalent mixture, but is 95 mol% or more of the difluoroionic complex contained in the nonaqueous electrolyte battery electrolyte. Is preferably (1-Cis). That is, even when (1-Trans) is included in the electrolyte for a nonaqueous electrolyte battery, the mass ratio (1-Trans) / (1-Cis) between (1-Cis) and (1-Trans) is , 0.05 or less is preferable.
- each element constituting the difluoroionic complex (1) is a combination of elements selected from the following (1a) to (1d) Either is preferable.
- a + which is a cation constituting the difluoroionic complex (1) is any one selected from the group consisting of metal ions, protons and onium ions, and the non-aqueous electrolyte solution and the non-aqueous electrolyte solution of the present invention.
- the type is not particularly limited as long as it does not impair the performance of the battery, but from the viewpoint of helping ion conduction in the non-aqueous electrolyte battery, lithium ion, sodium ion, potassium ion, or quaternary.
- Alkyl ammonium ions are preferred.
- the quaternary alkylammonium ion is not particularly limited, and examples thereof include trimethylpropylammonium and 1-butyl-1-methylpyrrolidinium.
- (1a-Cis) and (1a-Trans) are mixed at 1: 9 and 5: 5, respectively, is There is no change in the ratio between (1a-Cis) and (1a-Trans).
- the non-aqueous electrolyte solution of the present invention includes one or more ionic complexes selected from an electrolyte, a non-aqueous solvent or a mixture of polymers, and a cis-conformation ionic complex represented by the general formula (1-Cis). It is preferable that 0.001 mass% or more and 20.0 mass% or less are contained. By including (1-Cis), the output characteristics (particularly the low temperature output characteristics after repeated charge / discharge) are greatly improved.
- the content of (1-Cis) in the nonaqueous electrolytic solution is preferably 0.01% by mass or more and 10.0% by mass or less. More preferably, it is 0.1 mass% or more and 3.0 mass% or less.
- the amount is less than 0.001% by mass, the effect of improving the output characteristics of the non-aqueous electrolyte battery at low temperature may not be sufficiently obtained.
- the amount exceeds 10.0% by mass, the viscosity of the electrolyte increases. Therefore, the movement of cations in the non-aqueous electrolyte battery is hindered, which may cause a decrease in battery performance.
- the compound of group (II) is preferably composed of the following (II-1) to (II-4).
- (II-1) A carbonate having an unsaturated bond represented by the general formula (II-1a) and / or (II-1b).
- (II-2) A carbonate having a fluorine atom represented by the general formula (II-2a).
- (II-3) An acid anhydride represented by the general formula (II-3a).
- II-4) A compound having an isocyanato group represented by the general formula (II-4a). These may be used alone or in combination of two or more.
- O is an oxygen atom
- R 3 and R 4 are each independently a hydrogen atom, an alkyl group, a hydrocarbon group containing an unsaturated bond, an alkoxy group, a halogen, a halogen-containing alkyl group, or an aryl group. Provided that R 3 and R 4 may contain an ether bond.
- O is an oxygen atom
- R 5 is an alkyl group, a hydrocarbon group containing an unsaturated bond, or an alkoxy group.
- R 6 is a hydrogen atom, an alkyl group, a hydrocarbon group containing an unsaturated bond, or An alkoxy group, provided that R 5 and R 6 may contain an ether bond, and (II-1b) excludes the case of propylene carbonate.
- R 7 to R 10 are each independently a hydrogen atom, an alkyl group, a hydrocarbon group containing an unsaturated bond, an alkoxy group, a halogen, an alkyl group having a halogen, or an aryl group. is there. However, at least one of R 7 to R 10 has a fluorine atom. R 7 to R 10 may contain an ether bond. )
- O is an oxygen atom
- C is a carbon atom
- R 11 and R 12 are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, a haloalkyl group having 1 to 12 carbon atoms, or an alkenyl group having 2 to 12 carbon atoms, either one of R 11 and R 12 is a halogen atom, an alkyl group or a haloalkyl group having 1 to 12 carbon atoms having 1 to 12 carbon atoms.
- the R 11 R 12 and the carbon atom to which they are bonded may form a cyclic aliphatic acid anhydride.
- N represents a nitrogen atom
- C represents a carbon atom
- O represents an oxygen atom
- R 13 represents a chain hydrocarbon having 1 to 10 carbon atoms.
- N represents an integer of 1 to 2
- Examples of the carbonate having an unsaturated bond represented by the general formula (II-1a) include vinylene carbonate derivatives, such as vinylene carbonate, fluorovinylene carbonate, methyl vinylene carbonate, fluoromethyl vinylene carbonate, ethyl vinylene carbonate, propyl vinylene carbonate. More preferred is at least one selected from the group consisting of butyl vinylene carbonate, dipropyl vinylene carbonate, 4,5-dimethyl vinylene carbonate, 4,5-diethyl vinylene carbonate, trifluoromethyl vinylene carbonate, and the like. Of these, vinylene carbonate is more preferable.
- the carbonate having an unsaturated bond represented by the general formula (II-1b) for example, at least one selected from the group consisting of vinylethylene carbonate, ethynylethylene carbonate, divinylethylene carbonate, vinyloxyethylene carbonate and the like is preferable. Of these, vinyl ethylene carbonate and ethynyl ethylene carbonate are more preferable.
- Examples of the carbonate having a fluorine atom represented by the general formula (II-2a) include fluoroethylene carbonate, 4,4-difluoroethylene carbonate, 4,5-difluoroethylene carbonate, and 4,5-difluoro-4,5- At least one selected from the group consisting of dimethylethylene carbonate and the like is more preferable. Of these, fluoroethylene carbonate and 4,5-difluoroethylene carbonate are preferred. As 4,5-difluoroethylene carbonate, a trans isomer is preferable to a cis isomer. This is because 4,5-difluoroethylene carbonate (trans form) gives high ionic conductivity and forms a suitable interface protective film.
- Examples of the acid anhydride represented by the general formula (II-3a) include succinic anhydride, glutaric anhydride, maleic anhydride, citraconic anhydride, glutaconic anhydride, itaconic anhydride, cycloaliphatic acid anhydride, Examples thereof include 2-methyl succinic anhydride, 2-allyl succinic anhydride, 2- (2-methylallyl) succinic anhydride and the like.
- fluorine-substituted aliphatic acid anhydrides fluorinated carboxylic acid anhydrides such as trifluoroacetic anhydride, pentafluoropropionic anhydride, heptafluoro-n-butyric anhydride, difluoromaleic anhydride, tetrafluorosuccinic anhydride, tetrafluoroanhydride Fluorine-substituted cyclic aliphatic anhydrides such as citraconic acid, tetrafluoroglutaconic anhydride, tetrafluoroitaconic anhydride, hexafluoroglutaric anhydride and the like can be mentioned. Of these, succinic anhydride, maleic anhydride, 2-allyl succinic anhydride, tetrafluorosuccinic anhydride, and the like are more preferable.
- Examples of the compound having an isocyanato group represented by the general formula (II-4a) include 1-isocyanatoethane, 1-isocyanatopropane, 2-isocyanatopropane, 1-isocyanato-3-methoxypropane and 1-isocyanate.
- the difluoroionic complex (1-Trans) / difluoroionic complex (1-Cis) is in the range of 0.0001 to 0.05, preferably 0.001 to 0.03. More preferably, it is 0.002 to 0.01.
- NMR analysis as a method for quantifying the mass ratio (1-Trans) / (1-Cis) of (1-Cis) to (1-Trans) in the electrolyte, NMR analysis or liquid chromatography mass spectrometry (LC -MS).
- LC -MS liquid chromatography mass spectrometry
- tetrafluoroionic complex (1-Tetra) in which F is a four-molecule bond to a non-aqueous electrolyte containing (1-Cis) or (1-Cis) + (1-Trans). It is possible to suppress an increase in the internal pressure of the container when the non-aqueous electrolyte is stored for a long time.
- the tetrafluoroionic complex (1-Tetra) / difluoroionic complex (1-Cis) (mass ratio) is in the range of 0.02 to 0.25, preferably 0.05 to 0.00. 22, more preferably 0.07 to 0.20.
- Each element of the anion portion of the tetrafluoroionic complex (1-Tetra) is any of the following elements selected from (Tetra-a), (Tetra-b), (Tetra-c), and (Tetra-d): It is preferable that it is the combination of these.
- a + which is a cation constituting the tetrafluoroionic complex (1-Tetra) is any one selected from the group consisting of metal ions, protons and onium ions, and the non-aqueous electrolyte solution of the present invention and the non-aqueous electrolyte
- the type is not particularly limited as long as it does not impair the performance of the aqueous electrolyte battery, but from the viewpoint of helping ion conduction in the non-aqueous electrolyte battery, lithium ion, sodium ion, potassium ion, Or a quaternary alkyl ammonium ion is preferable.
- the quaternary alkylammonium ion is not particularly limited, and examples thereof include trimethylpropylammonium and 1-butyl-1-methylpyrrolidinium.
- the selectivity and speed of the reaction with the functional groups on the electrode surface are different from the generation of a reduction reaction decomposition product due to a reduction reaction between the cis form and the trans form due to steric factors and electronic factors.
- the initiation of the reduction reaction between the negative electrode and the difluorophosphate complex (cis, trans) will first be considered from steric factors.
- the portion where the difluorophosphate complex receives electrons from the negative electrode and the reduction proceeds first is a ligand portion other than F. (If it is 1a, carbon of the carbonyl group) Therefore, in order for the reduction to proceed, it is necessary to approach the negative electrode from the surface where F is not bonded.
- F is bound to the top and bottom of the molecule, so it is inevitably only when the molecule approaches the electrode from the right or left, that is, within a total range of 180 degrees left and right excluding 180 degrees.
- the reduction reaction proceeds.
- the positions of F are gathered in the same direction in the cis isomer, it is sufficient that the cis isomer can be approached within the range of 200 to 250 degrees in the opposite direction, and the probability that the reduction reaction proceeds is higher than that of the trans isomer.
- the LUMO level is slightly lower in the cis isomer but lower than the trans isomer. For this reason, the cis form is more likely to receive electrons from the electrode, and the reduction reaction proceeds faster.
- the difluorophosphate complex before decomposition is a hexacoordinate phosphorus compound, but the difluorophosphate derivative that is one of the main components of SEI after decomposition is a pentacoordinate phosphorus compound.
- the difluorophosphate complex is decomposed to produce a highly active intermediate, and the intermediate reacts with a functional group on the negative electrode surface, it changes from 6-coordinate to 5-coordinate.
- the bond angle of FPF before decomposition (6-coordinate) is 180 degrees, but the bond angle of FPF after decomposition (5-coordinate) is about 100 degrees. , Requires major structural changes.
- the cis isomer has only a slight change from 90 degrees (before decomposition, 6-coordinate) to about 100 degrees (5-coordinate after decomposition). From this fact, it can be seen that the energy in the transition state of the reductive decomposition reaction is smaller in the cis form without a large structural change, and the reductive decomposition of the cis form is more advantageous than the reductive decomposition of the trans form.
- This is not limited to phosphorus as the central element, but the same can be said for arsenic, antimony, and silicon.
- the cis isomer has a fast reductive decomposition reaction, and SEI having a difluorophosphoric acid derivative and a carbonic acid derivative as main components is quickly formed.
- SEI composed of a difluorophosphoric acid derivative is excellent in improving the cycle characteristics, high-temperature storage characteristics, and output characteristics of the battery, and SEI composed of a carbonic acid derivative is superior in improving cycle characteristics and high-temperature storage characteristics. It has become clear.
- the reductive decomposition reaction of the trans isomer is slower than that of the cis isomer, and it is difficult to quickly form SEI consisting only of the difluorophosphoric acid derivative and the carbonic acid derivative.
- the reduction reaction of the solvent proceeds in parallel with the result, resulting in the formation of SEI mainly composed of a difluorophosphoric acid derivative and a carbonic acid derivative derived from a difluorophosphoric acid complex, and a mixture of carbonic acid and an alkyl carbonate derived from the solvent.
- the difluorophosphate complex is much easier to decompose than the solvent, but the number of solvent molecules is enormous and the decomposition of the solvent proceeds to a small extent.
- the SEI comprising the alkyl carbonate contained therein is a cycle.
- the characteristics and high temperature storage characteristics are improved, the cation conductivity is reduced as compared with SEI made of a carbonic acid derivative due to a decrease in the proportion of oxygen, and the effect of improving the output characteristics may be limited or conversely reduced. is there.
- the negative electrode SEI made of an alkyl carbonate is disadvantageous in output characteristics because of its low ionic conductivity, but it is possible to suppress the release of lithium from the negative electrode during high temperature storage and to suppress the capacity drop after high temperature storage. .
- the high capacity is maintained even after high temperature storage, and when the high rate discharge capacity at low temperature is compared thereafter (output characteristics), the ratio of the amount of electricity obtained at high rate discharge compared to the low rate is Although it is lower than the electrolyte solution containing only (1-Cis), since the original capacity is large, the absolute value of the amount of electricity obtained during high-rate discharge is a certain amount of (1-Trans) relative to (1-Cis). ) Is added more than the electrolyte containing only (1-Cis).
- the tetrafluoroionic complex (1-Tetra) in which F is tetramolecularly bonded has a higher electron-withdrawing effect of F than the difluoroionic complex (1) in which F is bimolecularly bonded. Has fallen and is prone to nucleophilic attacks. Therefore, when a small amount of water is present in the electrolytic solution, (1-Tetra) is selectively hydrolyzed rather than (1). For example, when the central element M is P, the tetrafluorophosphate site constituting (1-Tetra) is converted into hexafluorophosphate by hydrolysis (ligands other than F are not released after elimination). Leveling).
- Ligand portions other than F are desorbed and decomposed from the central element P to release carbon dioxide and carbon monoxide.
- the amount of carbon dioxide and carbon monoxide released at this time is equivalent to 1 ⁇ 2 mole compared to (1), and as a result, the amount of carbon dioxide and carbon monoxide that causes an increase in internal pressure is greatly reduced. I can do it.
- the non-aqueous electrolyte is generally called a non-aqueous electrolyte, and if a polymer is used, the non-aqueous electrolyte is called a polymer solid electrolyte.
- the polymer solid electrolyte includes those containing a non-aqueous solvent as a plasticizer. It should be noted that this non-aqueous electrolyte, an anode material capable of reversibly inserting and desorbing alkali metal ions such as lithium ions and sodium ions, or alkaline earth metal ions, lithium ions and sodium ions, etc.
- An electrochemical device using a positive electrode material into which alkali metal ions or alkaline earth metal ions can be reversibly inserted and removed is called a non-aqueous electrolyte battery.
- the electrolyte is not particularly limited, and a salt composed of an arbitrary cation and anion pair can be used.
- a salt composed of an arbitrary cation and anion pair can be used.
- Specific examples include alkali metal ions such as lithium ions and sodium ions, alkaline earth metal ions, quaternary alkylammonium ions, etc. as cations.
- Examples of anions include hexafluorophosphoric acid, tetrafluoroboric acid, peroxides.
- One kind of these electrolytes may be used alone, or two or more kinds thereof may be mixed and used in an arbitrary combination and ratio according to the application.
- the cation is lithium, sodium, magnesium, quaternary alkylammonium cation
- the anion is hexafluorophosphoric acid, tetrafluoroboric acid, bis (trifluoromethanesulfonyl).
- Imide, bis (fluorosulfonyl) imide, and bis (difluorophosphonyl) imide anions are preferred.
- the non-aqueous solvent is not particularly limited as long as it is an aprotic solvent capable of dissolving the ionic complex of the present invention.
- an aprotic solvent capable of dissolving the ionic complex of the present invention.
- carbonates, esters, ethers, lactones, nitriles, imides , Sulfones and the like can be used.
- not only a single solvent but 2 or more types of mixed solvents may be sufficient.
- ethyl methyl carbonate dimethyl carbonate, diethyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, methyl butyl carbonate, ethylene carbonate, propylene carbonate, butylene carbonate, methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, Diethyl ether, acetonitrile, propionitrile, tetrahydrofuran, 2-methyltetrahydrofuran, furan, tetrahydropyran, 1,3-dioxane, 1,4-dioxane, dibutyl ether, diisopropyl ether, 1,2-dimethoxyethane, N, N- Examples include dimethylformamide, dimethyl sulfoxide, sulfolane, ⁇ -butyrolactone, and ⁇ -valerolactone.
- the nonaqueous solvent preferably contains at least one selected from the group consisting of cyclic carbonates and chain carbonates.
- cyclic carbonate include ethylene carbonate and propylene carbonate
- chain carbonate include ethyl methyl carbonate, dimethyl carbonate, diethyl carbonate, and methyl propyl carbonate.
- the polymer used for obtaining the polymer solid electrolyte containing the ionic complex of the present invention is not particularly limited as long as it is an aprotic polymer capable of dissolving the ionic complex or electrolyte.
- examples thereof include polymers having polyethylene oxide in the main chain or side chain, homopolymers or copolymers of polyvinylidene fluoride, methacrylic acid ester polymers, polyacrylonitrile and the like.
- a plasticizer is added to these polymers, the above-mentioned aprotic non-aqueous solvent can be used.
- the concentration of the electrolyte of the present invention in these ionic conductors is not particularly limited, but the lower limit is 0.5 mol / L or more, preferably 0.7 mol / L or more, more preferably 0.9 mol / L or more, Moreover, an upper limit is 5.0 mol / L or less, Preferably it is 4.0 mol / L or less, More preferably, it is the range of 2.0 mol / L or less. When the concentration is less than 0.5 mol / L, the ionic conductivity decreases, thereby reducing the cycle characteristics and output characteristics of the non-aqueous electrolyte battery.
- the concentration exceeds 5.0 mol / L
- the viscosity of the non-aqueous electrolyte increases.
- the ionic conduction may be lowered, and the cycle characteristics and output characteristics of the non-aqueous electrolyte battery may be degraded.
- the lithium salt in the non-aqueous electrolyte does not exceed 40 ° C. so that the temperature of the non-aqueous electrolyte does not exceed 40 ° C.
- Generation of free acid such as hydrogen fluoride (HF) due to reaction and decomposition can be suppressed, and as a result, decomposition of non-aqueous solvent can also be suppressed, which is effective in preventing deterioration of non-aqueous electrolyte. .
- the lithium salt dissolution step if the lithium salt is dissolved and prepared by adding a small amount so that the total lithium salt has a concentration of 0.5 to 4.0 mol / L, a free acid such as HF is similarly produced. It becomes possible to suppress it.
- a non-aqueous solvent first, the range of 10 to 35% by mass of the total lithium salt is added and dissolved, and then the range of 10 to 35% by mass of the total lithium salt is further added and dissolved to 2 to 2%. Nine times, and finally, the remaining lithium salt is gradually added and dissolved, so that the liquid temperature does not exceed 40 ° C.
- the side reaction is likely to proceed due to an increase in the temperature of the non-aqueous electrolyte solution at the time of preparation, so the liquid temperature of the non-aqueous electrolyte solution exceeds 40 ° C.
- the temperature rise so as not to occur, deterioration of the non-aqueous electrolyte solution can be prevented, and the quality can be maintained.
- additives generally used in the non-aqueous electrolyte solution of the present invention may be added at an arbitrary ratio.
- Specific examples include cyclohexylbenzene, biphenyl, tert-butylbenzene, tert-amylbenzene, biphenyl, o-terphenyl, 4-fluorobiphenyl, fluorobenzene, 2,4-difluorobenzene, difluoroanisole, 1,3-propane.
- Examples include compounds having an overcharge preventing effect, a negative electrode film forming effect, and a positive electrode protecting effect, such as sultone, 1,3-propene sultone, methylene methane disulfonate, dimethylene methane disulfonate, and trimethylene methane disulfonate.
- a non-aqueous electrolyte by quasi-solidifying it with a gelling agent or a cross-linked polymer as used in a non-aqueous electrolyte battery called a polymer battery.
- Non-aqueous electrolyte battery of the present invention includes (a) the non-aqueous electrolyte described above, (b) a positive electrode, (c) a negative electrode, and (d) a separator.
- the non-aqueous electrolyte battery of the present invention has ⁇ 1.
- Non-aqueous electrolyte solution described in ⁇ Non-aqueous electrolyte solution> is provided.
- the positive electrode preferably contains at least one oxide and / or polyanion compound as a positive electrode active material.
- the positive electrode active material constituting the positive electrode is not particularly limited as long as it is various materials that can be charged and discharged.
- the positive electrode active material constituting the positive electrode is not particularly limited as long as it is various materials that can be charged and discharged.
- mold phosphate and the lithium excess layered transition metal oxide which has (D) layered rock salt type structure is mentioned.
- lithium transition metal composite oxide Cathode active material
- lithium transition metal composite oxides containing at least one metal selected from nickel, manganese and cobalt and having a layered structure include lithium-cobalt composite oxides and lithium-nickel composite oxides. Lithium / nickel / cobalt composite oxide, lithium / nickel / cobalt / aluminum composite oxide, lithium / cobalt / manganese composite oxide, lithium / nickel / manganese composite oxide, lithium / nickel / manganese / cobalt composite oxide Etc.
- transition metal atoms that are the main components of these lithium transition metal composite oxides are Al, Ti, V, Cr, Fe, Cu, Zn, Mg, Ga, Zr, Si, B, Ba, Y, Sn. Those substituted with other elements such as may also be used.
- lithium-cobalt composite oxide and the lithium-nickel composite oxide include LiCoO 2 , LiNiO 2 , lithium cobalt oxide to which a different element such as Mg, Zr, Al, and Ti is added (LiCo 0.98 Mg 0. 01 Zr 0.01 O 2 , LiCo 0.98 Mg 0.01 Al 0.01 O 2 , LiCo 0.975 Mg 0.01 Zr 0.005 Al 0.01 O 2 ), international application WO 2014/034043 You may use the lithium cobaltate etc. which fixed the rare earth compound to the surface as described in the gazette. Further, as described in Japanese Patent Application Laid-Open No. 2002-151077, etc., a part of the particle surface of LiCoO 2 particle powder coated with aluminum oxide may be used.
- the lithium / nickel / cobalt composite oxide and the lithium / nickel / cobalt / aluminum composite oxide are represented by the general formula (1-1). LiaNi 1- bc Co b M 1 c O 2 (1-1)
- M 1 is at least one element selected from the group consisting of Al, Fe, Mg, Zr, Ti, and B, a is 0.9 ⁇ a ⁇ 1.2, and b , C satisfy the conditions of 0.1 ⁇ b ⁇ 0.3 and 0 ⁇ c ⁇ 0.1.
- LiNi 0.8 Co 0.2 O 2 LiNi 0.85 Co 0.10 Al 0.05 O 2 , LiNi 0.87 Co 0.10 Al 0.03 O 2 , LiNi 0.6 Examples include Co 0.3 Al 0.1 O 2 .
- lithium / cobalt / manganese composite oxide and the lithium / nickel / manganese composite oxide include LiNi 0.5 Mn 0.5 O 2 and LiCo 0.5 Mn 0.5 O 2 .
- lithium / nickel / manganese / cobalt composite oxide examples include a lithium-containing composite oxide represented by the general formula (1-2). Li d Ni e Mn f Co g M 2 h O 2 (1-2)
- M 2 is at least one element selected from the group consisting of Al, Fe, Mg, Zr, Ti, B, and Sn, and d is 0.9 ⁇ d ⁇ 1.2.
- Lithium / nickel / manganese / cobalt composite oxides contain manganese in the range represented by the general formula (1-2) in order to improve structural stability and improve safety at high temperatures in lithium secondary batteries.
- Li [Ni 1/3 Mn 1/3 Co 1/3 ] O 2 Li [Ni 0.45 Mn 0.35 Co 0.2 ] having a charge / discharge region of 4.3 V or higher.
- O 2 Li [Ni 0.5 Mn 0.3 Co 0.2 ] O 2 , Li [Ni 0.6 Mn 0.2 Co 0.2 ] O 2 , Li [Ni 0.49 Mn 0.3 Co 0.2 Zr 0.01 ] O 2 , Li [Ni 0.49 Mn 0.3 Co 0.2 Mg 0.01 ] O 2 and the like.
- lithium manganese composite oxide having spinel structure examples include a spinel type lithium manganese composite oxide represented by the general formula (1-3). Li j (Mn 2 -kM 3 k ) O 4 (1-3)
- M 3 is at least one metal element selected from the group consisting of Ni, Co, Fe, Mg, Cr, Cu, Al, and Ti, and j is 1.05 ⁇ j ⁇ 1. 15 and k is 0 ⁇ k ⁇ 0.20.
- LiMn 2 O 4 LiMn 1.95 Al 0.05 O 4 , LiMn 1.9 Al 0.1 O 4 , LiMn 1.9 Ni 0.1 O 4 , LiMn 1.5 Ni 0.5 O 4 etc. are mentioned.
- (C) Lithium-containing olivine-type phosphate examples include those represented by the general formula (1-4). LiFe 1-n M 4 n PO 4 (1-4)
- M 4 is at least one selected from Co, Ni, Mn, Cu, Zn, Nb, Mg, Al, Ti, W, Zr, and Cd, and n is 0 ⁇ n ⁇ 1.
- LiFePO 4 , LiCoPO 4 , LiNiPO 4 , LiMnPO 4 and the like can be mentioned, among which LiFePO 4 and / or LiMnPO 4 are preferable.
- lithium-excess layered transition metal oxide examples include those represented by the general formula (1-5).
- x is 0 ⁇ a number satisfying x ⁇ 1
- M 5 is at least one or more metal elements mean oxidation number is 3 +
- M 6 the average oxide the number is at least one or more metal elements 4 +.
- M 5 is preferably one or more metal elements selected from trivalent Mn, Ni, Co, Fe, V, and Cr. The average oxidation number may be trivalent with an amount of metal.
- M 6 is preferably one or more metal elements selected from Mn, Zr, and Ti. Specifically, 0.5 [LiNi 0.5 Mn 0.5 O 2 ] ⁇ 0.5 [Li 2 MnO 3 ], 0.5 [LiNi 1/3 Co 1/3 Mn 1/3 O 2 ] 0.5 [Li 2 MnO 3 ], 0.5 [LiNi 0.375 Co 0.25 Mn 0.375 O 2 ], 0.5 [Li 2 MnO 3 ], 0.5 [LiNi 0.375 Co 0.125 Fe 0.125 Mn 0.375 O 2 ] ⁇ 0.5 [Li 2 MnO 3 ], 0.45 [LiNi 0.375 Co 0.25 Mn 0.375 O 2 ] ⁇ 0.10 [Li 2 TiO 3 ] ⁇ 0.45 [Li 2 MnO 3 ] and the like.
- the positive electrode active material (D) represented by the general formula (1-5) is known to exhibit a high capacity when charged at a high voltage of 4.4 V (Li standard) or higher (for example, US Pat. No. 7 , 135, 252).
- positive electrode active materials can be prepared according to the production methods described in, for example, JP 2008-270201 A, International Publication WO 2013/118661, JP 2013-030284 A, and the like.
- the positive electrode active material may contain at least one selected from the above (A) to (D) as a main component, but other examples include FeS 2 , TiS 2 , V 2 0 5. , Transition element chalcogenides such as MoO 3 and MoS 2 , or conductive polymers such as polyacetylene, polyparaphenylene, polyaniline, and polypyrrole, activated carbon, polymers that generate radicals, and carbon materials.
- the positive electrode has a positive electrode current collector.
- the positive electrode current collector for example, aluminum, stainless steel, nickel, titanium, or an alloy thereof can be used.
- a positive electrode active material layer is formed on at least one surface of the positive electrode current collector.
- a positive electrode active material layer is comprised by the above-mentioned positive electrode active material, a binder, and a electrically conductive agent as needed, for example.
- binder examples include polytetrafluoroethylene, polyvinylidene fluoride, or styrene butadiene rubber (SBR) resin.
- SBR styrene butadiene rubber
- a carbon material such as acetylene black, ketjen black, carbon fiber, or graphite (granular graphite or flake graphite) can be used.
- acetylene black or ketjen black having low crystallinity.
- the negative electrode includes a negative electrode active material.
- the negative electrode active material constituting the negative electrode can be doped / dedoped with lithium ions.
- the negative electrode active material constituting the negative electrode can be doped / dedoped with lithium ions.
- E a carbon material having a d-value of 0.340 nm or less in the lattice plane (002 plane) in X-ray diffraction
- F a carbon having a d-value in the lattice plane (002 plane) in X-ray diffraction exceeding 0.340 nm.
- a material (G) an oxide of one or more metals selected from Si, Sn, Al, (H) one or more metals selected from Si, Sn, Al, alloys containing these metals, or these metals or alloys; Examples include an alloy with lithium and (I) at least one selected from lithium titanium oxide.
- These negative electrode active materials can be used individually by 1 type, and can also be used in combination of 2 or more type.
- Examples of the carbon material having a d value of 0.340 nm or less in the lattice plane (002 plane) in the negative electrode active material (E) X-ray diffraction include pyrolytic carbons and cokes (for example, pitch coke, needle coke, and petroleum coke).
- Graphites organic polymer compound fired bodies (for example, those obtained by firing and carbonizing a phenol resin, furan resin, etc.), carbon fibers, activated carbon, and the like. These may be graphitized.
- the carbon material has a (002) plane spacing (d002) of 0.340 nm or less measured by an X-ray diffraction method.
- d002 plane spacing
- graphite having a true density of 1.70 g / cm 3 or more, or A highly crystalline carbon material having close properties is preferred.
- amorphous carbon As the carbon material in which the d value of the lattice plane (002 plane) in the negative electrode active material (F) X-ray diffraction exceeds 0.340 nm, amorphous carbon can be cited, which is obtained by heat treatment at a high temperature of 2000 ° C. or higher. Is a carbon material whose stacking order hardly changes. Examples thereof include non-graphitizable carbon (hard carbon), mesocarbon microbeads (MCMB) baked at 1500 ° C. or less, and mesopage bitch carbon fiber (MCF). A typical example is Carbotron (registered trademark) P manufactured by Kureha Co., Ltd.
- Negative electrode active material (G) One or more metal oxides selected from Si, Sn, and Al)
- Negative electrode active material (G) One or more metal oxides selected from Si, Sn, and Al can be doped / dedoped with lithium ions, such as silicon oxide and tin oxide. .
- SiO x having a structure in which ultrafine particles of Si are dispersed in SiO 2 .
- this material is used as the negative electrode active material, since Si that reacts with Li is ultrafine particles, charging and discharging are performed smoothly, while the SiO x particles having the above structure itself have a small surface area.
- the coating properties and the adhesion of the negative electrode mixture layer to the current collector when the composition (paste) is used to form the film are also good.
- SiO x large volume change during charge and discharge, SiO x and above the negative electrode active material negative active material with high capacity by combining a good charge-discharge cycle characteristics at a specific ratio and a graphite (E) And both.
- Negative electrode active material (H) one or more metals selected from Si, Sn, Al, alloys containing these metals, or alloys of these metals or alloys and lithium)
- Negative electrode active material (H) one or more metals selected from Si, Sn, Al, alloys containing these metals, or alloys of these metals or alloys and lithium include, for example, metals such as silicon, tin, and aluminum, and silicon alloys , Tin alloys, aluminum alloys, and the like, and materials in which these metals and alloys are alloyed with lithium during charge and discharge can also be used.
- Examples of the negative electrode active material (I) lithium titanium oxide include lithium titanate having a spinel structure and lithium titanate having a ramsdellite structure.
- lithium titanate having a spinel structure examples include Li 4 + ⁇ Ti 5 O 12 ( ⁇ varies within the range of 0 ⁇ ⁇ ⁇ 3 due to charge / discharge reaction).
- lithium titanate having a ramsdellite structure examples include Li 2 + ⁇ Ti 3 O 7 ( ⁇ varies within the range of 0 ⁇ ⁇ ⁇ 3 due to charge / discharge reaction).
- These negative electrode active materials can be prepared according to the production methods described in, for example, Japanese Patent Application Laid-Open No. 2007-018883 and Japanese Patent Application Laid-Open No. 2009-176752.
- the cation in the nonaqueous electrolytic solution is mainly sodium
- hard carbon oxides such as TiO 2 , V 2 O 5 , and MoO 3 are used as the negative electrode active material.
- a sodium-containing transition metal composite oxide such as NaFeO 2 , NaCrO 2 , NaNiO 2 , NaMnO 2 , and NaCoO 2 as a positive electrode active material
- transition metals such as Fe, Cr, Ni, Mn, Co, etc.
- transition metal phosphate compounds such as Na 2 FeP 2 O 7 , NaCo 3 (PO 4 ) 2 P 2 O 7
- sulfides such as TiS 2 and FeS 2
- polyacetylene polypara Conductive polymers such as phenylene, polyaniline, and polypyrrole, activated carbon, polymers that generate radicals, carbon Material and the like are used.
- the negative electrode has a negative electrode current collector.
- the negative electrode current collector for example, copper, stainless steel, nickel, titanium, or an alloy thereof can be used.
- a negative electrode active material layer is formed on at least one surface of the negative electrode current collector.
- a negative electrode active material layer is comprised by the above-mentioned negative electrode active material, a binder, and a electrically conductive agent as needed, for example.
- binder examples include polytetrafluoroethylene, polyvinylidene fluoride, or styrene butadiene rubber (SBR) resin.
- SBR styrene butadiene rubber
- a carbon material such as acetylene black, ketjen black, carbon fiber, or graphite (granular graphite or flake graphite) can be used.
- the electrode is obtained, for example, by dispersing and kneading an active material, a binder, and, if necessary, a conductive agent in a solvent such as N-methyl-2-pyrrolidone (NMP) or water in a predetermined blending amount.
- NMP N-methyl-2-pyrrolidone
- the paste can be applied to a current collector and dried to form an active material layer.
- the obtained electrode is preferably compressed by a method such as a roll press to adjust the electrode to an appropriate density.
- the non-aqueous electrolyte battery of the present invention includes (d) a separator.
- a separator for preventing the contact between the positive electrode and the (c) negative electrode a nonwoven fabric or a porous sheet made of polyolefin such as polypropylene or polyethylene, cellulose, paper, glass fiber or the like is used. These films are preferably microporous so that the electrolyte can penetrate and ions can easily pass therethrough.
- the polyolefin separator examples include a membrane that electrically insulates the positive electrode and the negative electrode and is permeable to lithium ions, such as a microporous polymer film such as a porous polyolefin film.
- a porous polyolefin film for example, a porous polyethylene film alone or a porous polyethylene film and a porous polypropylene film may be overlapped and used as a multilayer film.
- the composite film etc. of the porous polyethylene film and the polypropylene film are mentioned.
- a metal can such as a coin shape, a cylindrical shape, or a square shape, or a laminate exterior body can be used.
- the metal can material include a steel plate subjected to nickel plating, a stainless steel plate, a stainless steel plate subjected to nickel plating, aluminum or an alloy thereof, nickel, and titanium.
- the laminate outer package for example, an aluminum laminate film, a SUS laminate film, a laminate film made of silica-coated polypropylene, polyethylene, or the like can be used.
- the configuration of the non-aqueous electrolyte battery according to the present embodiment is not particularly limited.
- an electrode element in which a positive electrode and a negative electrode are opposed to each other and a non-aqueous electrolyte are included in an outer package. It can be set as a structure.
- the shape of the non-aqueous electrolyte battery is not particularly limited, but an electrochemical device having a shape such as a coin shape, a cylindrical shape, a square shape, or an aluminum laminate sheet type is assembled from the above elements.
- a synthesis method of a difluoroionic complex (cis isomer / trans isomer) and a tetrafluoroionic complex is shown below.
- an ionic complex was synthesized using the method disclosed in Patent Document 19 or by applying the method disclosed in Non-Patent Document 1 and Patent Document 17, but synthesis by other methods is also possible. Is possible. In either case, the raw materials and products were handled in a nitrogen atmosphere with a dew point of -50 ° C or lower. The glass reactor used was one that had been dried at 150 ° C. for 12 hours or more and then cooled to room temperature under a nitrogen stream having a dew point of ⁇ 50 ° C. or less.
- DMC (60 mL) was added to dissolve the concentrated residue as much as possible, and then concentrated until the Li salt concentration was about 45% by mass. After removing insoluble components such as oxalic acid by filtration, 49 g of a DMC solution containing a mixture of (1a-Cis) and (1a-Trans) was obtained. Dichloromethane (hereinafter referred to as “CH 2 Cl 2 ”) was added to the DMC solution of the mixture at room temperature and stirred for 12 hours to precipitate a solid. The solid and mother liquor were separated by filtration, and DMC was distilled off from the mother liquor until a solid was obtained under reduced pressure.
- CH 2 Cl 2 Dichloromethane
- the solid obtained by filtration and the solid obtained from the mother liquor were separately dissolved in DMC, and a DMC solution having a concentration of about 45% by mass was prepared separately, and then CH 2 Cl 2 was added to precipitate the solid.
- the solids were collected by filtration, and the same procedure was repeated several times to prepare a DMC solution having a concentration of about 45% by mass and solid precipitation to obtain (1a) having F and P purity of 99.9 mol% (from NMR). -Cis) and (1a-Trans) were obtained.
- FIG. 1 shows the analysis result (ortep diagram) of (1a-Cis). (1a-Cis) was confirmed to be a cis conformation in which two molecules of fluorine were bonded in the same direction as viewed from the central element.
- (1a-Cis) and (1a-Trans) have the same mass and peaks are observed at different positions in F-NMR and P-NMR, they are compounds having the same atomic composition and different structures. it is obvious. Further, (1a-Trans) was confirmed by a single crystal X-ray structural analysis to be a trans conformation in which two molecules of fluorine were bonded in the opposite direction when viewed from the central element.
- a (1a-Cis) / EMC solution having a concentration of 10% by mass was prepared, and the dried ion exchange resin having a weight half the liquid weight was added thereto, followed by stirring at 25 ° C. for 6 hours. Thereafter, by removing the ion exchange resin by filtration, a (6a-Cis) / EMC solution (concentration of about 10% by mass) in which cations were exchanged from Li + to Na + was obtained. When the cation was quantified by ion chromatography, the ratio of Na + / Li + was 99.5.
- the (6a-Trans) / EMC solution having a concentration of about 10% by mass is similarly obtained. Obtained.
- LiPF 6 was added as an electrolyte to a non-aqueous solvent (volume ratio 1: 2) of ethylene carbonate (EC) and ethyl methyl carbonate (EMC) previously heated and dissolved in a nitrogen atmosphere dry box having a dew point of ⁇ 50 ° C. or less. After dissolving and preparing so as to have a concentration of 1 mol / L, various ionic complexes / EMC solutions according to the present invention and the compounds of the group (II) described above are added, whereby the nonaqueous electrolysis of the present invention shown below is performed. Liquid No. 1-1 to 1-41 were prepared.
- Nonaqueous electrolyte No. Preparation of 1-12 to 1-24 As an ionic complex according to the present invention, (1a-Cis) of Synthesis Example 1 is added in a predetermined amount described in Table 1 below, and VC is added as a compound of the group (II) described above in a predetermined amount described in Table 1 below. Further, (1a-Trans) of Synthesis Example 1 is added as the compound of Group (III) and / or (5a-Tetra) of Synthesis Example 2 is added as the compound of Group (IV). Therefore, non-aqueous electrolyte No. 1-12 to 1-24 were prepared.
- Nonaqueous electrolyte No. Preparation of 1-32 to 1-41 As the ionic complex according to the present invention, a predetermined amount of each of the cis-forms of Synthesis Example 1, Synthesis Example 4, Synthesis Example 6 to Synthesis Example 9 was added, and VC was selected as the compound of the group (II). Each of the trans isomers of Synthesis Example 1, Synthesis Example 4, Synthesis Example 6 to Synthesis Example 9 as a compound, and (5a-Tetra) of Synthesis Example 2 as a compound of the group (IV) described above in the predetermined amounts shown in Table 1 below By adding the non-aqueous electrolyte solution No. 1-32 to 1-41 were prepared.
- Comparative electrolyte No. Preparation of 1-3 Comparative electrolyte No. In the same manner as in 1-2, by adding a predetermined amount of (1a-Cis) of Synthesis Example 1 and (1b-Cis) of Synthesis Example 3 as shown in Table 1 below, the comparative electrolyte No. 1-3 was prepared.
- Comparative electrolyte No. Preparation of 1-4 Comparative electrolyte No. As in Table 1-2, as shown in Table 1, the comparative electrolyte No. By adding 1.0 mass% of VC instead of (1a-Cis) added in 1-2, the comparative electrolyte No. 1-4 was prepared.
- Comparative electrolyte No. Preparation of 1-5 Comparative electrolyte No. As in 1-4, VC was added in an amount of 1.0% by mass, and (1a-Trans) of Synthesis Example 1 was added in a predetermined amount as shown in Table 1 below. 1-5 was prepared.
- Comparative electrolyte No. Preparation of 1-6 Comparative electrolyte No. As in 1-4, 1.0% by mass of VC was added, and (1a-Trans) of Synthesis Example 1 and (5a-Tetra) of Synthesis Example 2 were added in predetermined amounts described in Table 1 below. Comparative electrolyte No. 1-6 was prepared.
- Non-aqueous electrolyte No. 1-1 to 1-41 and comparative electrolyte No. Each of 1-1 to 1-6 was subjected to an acceleration test in order to evaluate the stability during storage.
- a 20 L stainless steel pressure vessel equipped with a pressure gauge was filled with 21 kg of a non-aqueous electrolyte solution and stored at an environmental temperature of 45 ° C. for 2 months. Thereafter, the internal pressure in the container was measured at an ambient temperature of 25 ° C., and the amount of gas generated during storage was calculated.
- Compare electrolyte No. Table 1 shows the relative values when the gas generation amount of 1-1 is 100.
- a non-aqueous electrolyte solution (electrolyte solution No. 1) containing three types of compounds: difluoroionic complex (1a-Cis) in the cis conformation of Synthesis Example 1, VC, and tetrafluoroionic complex (5a-Tetra) of Synthesis Example 2. 1-15 to 1-17), and similarly, (1a-Cis), VC, (1a-Trans), and tetrafluoroionic complex (5a-Tetra), a non-aqueous electrolyte solution (electrolysis) The liquid Nos. 1-18 to 1-24) were compared with the non-aqueous electrolytes (electrolytes Nos.
- the gas generation suppression effect is the ratio of the tetrafluoroionic complex (5a-Tetra) to the difluoroionic complex (1a-Cis), that is, the tetrafluoroionic complex (1-Tetra) / difluoroionic complex ( 1-Cis) (mass ratio) increased from 0.07 to 0.12, 0.20, and it was confirmed that the gas generation suppression effect increased (for example, “Electrolytic Solution No. 1”). ⁇ 15 to 1-17 ”).
- non-aqueous electrolyte solution No. 1 shown in Table 1 was placed in an aluminum laminate exterior cell (capacity 30 mAh) comprising the above test NMC positive electrode, a test graphite negative electrode, and a cellulose separator.
- 1-1 to 1-41 and comparative electrolyte No. 1-1 to 1-6 were impregnated, respectively, to obtain non-aqueous electrolyte batteries according to Examples 1-1 to 1-41 and Comparative Examples 1-1 to 1-6.
- charging / discharging cycle is performed three times by charging at a constant current / constant voltage at a charging upper limit voltage of 4.3V and a 0.2C rate (6 mA) and discharging at a constant current of 0.2C (6 mA) to a discharge end voltage of 3.0V. Repeated. After this conditioning, a charge / discharge test at an environmental temperature of 60 ° C. was performed.
- Charging is performed at a constant current / constant voltage charging at a 3C rate (90 mA) up to a charging upper limit voltage of 4.3V, and discharging is performed at a charging / discharging cycle in which discharging is performed at a 3C rate (90 mA) constant current up to a discharge end voltage of 3.0V. Repeated 500 times. Subsequently, the non-aqueous electrolyte battery was cooled to 25 ° C., discharged to 3.0 V again, and then subjected to constant current and constant voltage charging to 4.3 V at 0 ° C. and a 0.2 C rate.
- the discharge is performed at a constant current at a 5 C rate (150 mA) up to a discharge end voltage of 3.0 V while maintaining the temperature at 0 ° C., and the capacity obtained at this time is expressed as low-temperature characteristics (0 ° C.) after 60 ° C. long-term cycle. did.
- the nonaqueous electrolyte battery is subsequently cooled to 25 ° C. and discharged to 3.0 V again.
- constant current and constant voltage charging was performed up to 4.3 V at 25 ° C. and 5 C rate.
- the discharge is performed at a constant current at a 5C rate (150 mA) up to a discharge end voltage of 3.0 V while maintaining the temperature at 25 ° C., and the capacity obtained at this time is a 5C rate characteristic after a long cycle of 60 ° C. (25 ° C.). It was.
- the discharge was performed at a constant current of 5 C rate (150 mA) up to a final discharge voltage of 3.0 V, and the capacity obtained at this time was set as a low temperature characteristic (0 ° C.) after storage at 60 ° C. .
- Example 1-4 Comparing Example 1-4 and Comparative Example 1-2, the non-aqueous electrolyte battery containing the same (1a-Cis) and VC is more non-aqueous electrolyte battery containing the same (1a-Cis). It was confirmed that the effect was higher.
- the non-aqueous electrolyte solution of the present invention contains a difluoroionic complex (1a-Cis) and a carbonate having an unsaturated bond such as VC, so that these additives are difluoroionic complex ( 1a-Cis) and VC are reduced and decomposed on the negative electrode in this order to form a stable coating (SEI) on the negative electrode surface.
- this reaction coating layer has high ionic conductivity and long-term stable SEI covers the negative electrode surface, side reactions such as decomposition of the solvent that have occurred on the negative electrode surface are suppressed. It is presumed that not only the initial irreversible capacity of the battery is suppressed, but also the long-term durability and output characteristics are improved.
- Example 1-1 to Example 1-11 Comparing Example 1-1 to Example 1-11, the effects of the difluoroionic complex (1a-Cis) and VC can be slightly confirmed even when the respective contents are 0.05% by mass. It was confirmed that the content of the ionic complex increased as it increased from 0.05% by mass to 0.1, 0.5, and 1.0% by mass. Further, when comparing Example 1-4 and Comparative Example 1-5, the non-aqueous electrolyte battery containing the cis-constant difluoroionic complex (1a-Cis) of Example 1-4 and VC is more preferable.
- Example 1-16 and Comparative Example 1-6 are compared, a non-aqueous electrolyte solution containing three types of compounds (1a-Cis), VC, and (IV) group (5a-Tetra) It has been confirmed that the battery is more effective than the non-aqueous electrolyte battery containing the trans-conformation difluoroionic complex (1a-Trans) and VC, and (5a-Tetra) as a compound of group (IV). It was.
- the (Cis) (mass ratio) increases from 0.002 to 0.005, 0.01, the discharge capacity after storage at 60 ° C. (0 ° C. without adversely affecting the discharge capacity after long-term cycle at 60 ° C. (0 ° C.) ) was somewhat improved.
- the ratio of the tetrafluoroionic complex (5a-Tetra) to the difluoroionic complex (1a-Cis) in cis conformation that is, the tetrafluoroionic complex (5a-Tetra) / difluoroionic complex (1-Cis)
- Discharge capacity after 60 ° C storage without adversely affecting 60 ° C long-term cycle discharge capacity (0 ° C) as (mass ratio) increases from 0.07 to 0.12, 0.20 The tendency which (0 degreeC) improves has been confirmed.
- Example 1-36 when the central element was changed from P to Si (1c-Cis), the solubility was low, and 1.0 mass% was not sufficiently dissolved, but 0.8 mass% was added. A relatively good effect was observed.
- difluoroionic complexes (6a-Trans, 6b-Trans, 6c-Trans, 6d-Trans) of trans conformations of different cationic species Similarly, when a trans-conformation difluoroionic complex (1c-Trans) in which the central element is changed from P to Si is added, the discharge capacity after 60 ° C long-term cycle (0 ° C) is higher than that of Comparative Example 1-1. 5C rate characteristics after 60 ° C. long-term cycle were obtained.
- Nonaqueous Electrolytic Solution No. Preparation of 2-1 to 2-31 Non-aqueous electrolyte No. 1 of the present invention.
- 2-1 to 2-31 the above-mentioned non-aqueous electrolyte No. Prepared in the same procedure as 1-1 to 1-41.
- EC and EMC volume ratio 1: 2 as non-aqueous solvents and LiPF 6 as an electrolyte were dissolved and prepared so as to have a concentration of 1 mol / L, and then various ionic complexes / EMC solutions according to the present invention.
- a compound of the above group (II) the following non-aqueous electrolyte solution No.
- Each of 2-1 to 2-31 was prepared.
- Nonaqueous electrolyte No. Preparation of 2-1 to 2-11 As the ionic complex according to the present invention, (1a-Cis) of Synthesis Example 1 is added in a predetermined amount described in Table 3 to be described later, and VEC is further added in a predetermined amount described in Table 3, so that the non-aqueous electrolyte solution No. . 2-1 to 2-11 were prepared.
- Nonaqueous electrolyte No. Preparation of 2-12 to 2-24 As a ionic complex according to the present invention, (1a-Cis) of Synthesis Example 1 was added in a predetermined amount described in Table 3 below, and VEC was added as a compound of the above-mentioned (II) group in a predetermined amount described in Table 3 below. Further, (1a-Trans) of Synthesis Example 1 is added as the compound of Group (III) and / or (5a-Tetra) of Synthesis Example 2 is added as the compound of Group (IV). Therefore, non-aqueous electrolyte No. 2-12 to 2-24 were prepared.
- Comparative electrolyte No. Preparation of 2-1 Comparative electrolyte No.
- VEC was added in an amount of 1.0% by mass instead of VC, so that the comparative electrolyte No. 2-1 was prepared.
- Comparative electrolyte No. Preparation of 2-2 Comparative electrolyte No. In the same procedure and composition as in 1-5, 1.0% by mass of VEC was added instead of VC as described in Table 3 below, and (1a-Trans) of Synthesis Example 1 was added in Table 3 below. By adding the predetermined amount described in the above, comparative electrolyte No. 2-2 was prepared.
- Comparative electrolyte No. Preparation of 2-3 Comparative electrolyte No. In the same procedure and composition as in 1-6, 1.0% by mass of VEC was added instead of VC as described in Table 3 below, and (1a-Trans) of Synthesis Example 1 was added in Table 3 below. By adding the predetermined amount described in the above, comparative electrolyte No. 2-3 was prepared.
- Each of 2-1, 2-2, and 2-3 was subjected to an acceleration test in order to evaluate the stability during storage.
- a 20 L stainless steel pressure vessel equipped with a pressure gauge was filled with 21 kg of a non-aqueous electrolyte solution and stored at an environmental temperature of 45 ° C. for 2 months. Thereafter, the internal pressure in the container was measured at an ambient temperature of 25 ° C., and the amount of gas generated during storage was calculated.
- the comparative electrolyte No. Table 3 shows the relative values when the gas generation amount of 1-1 is 100.
- Non-aqueous electrolyte solution (electrolyte solution No. 1) containing three kinds of compounds of difluoroionic complex (1a-Cis), VEC of synthesis example 1 and tetrafluoroionic complex (5a-Tetra) of synthesis example 2 2-15 to 2-17), and similarly, (1a-Cis), VEC, (1a-Trans), and a non-aqueous electrolytic solution (electrolysis) containing four types of compounds of a tetrafluoroionic complex (5a-Tetra) Liquid Nos. 2-18 to 1-24) were compared with non-aqueous electrolytes (electrolytes Nos.
- the gas generation suppression effect is the ratio of the tetrafluoroionic complex (5a-Tetra) to the difluoroionic complex (1a-Cis), that is, the tetrafluoroionic complex (1-Tetra) / difluoroionic complex ( 1-Cis) (mass ratio) increased from 0.07 to 0.12, 0.20, and it was confirmed that the effect of suppressing gas generation increased (for example, “Electrolytic Solution No. 2”). -15 to 2-17 ").
- Example 2-1 to Example 2-31 and Comparative Example 2-1 to Comparative Example 2-3-Production and Evaluation of Nonaqueous Electrolyte Battery In the same procedure as the non-aqueous electrolyte batteries according to Examples 1-1 to 1-41 and Comparative Examples 1-1 to 1-6, the test NMC positive electrode, the test graphite negative electrode, and cellulose A non-aqueous electrolyte solution No. 1 described in Table 3 was applied to an aluminum laminate exterior cell (capacity 30 mAh) provided with a separator. 2-1 to 2-31, Comparative electrolyte No. 2-1 and 2-2 were impregnated, respectively, to prepare non-aqueous electrolyte batteries according to Example 2-1 to Example 2-31 and Comparative Example 2-1 to Comparative Example 2-3.
- Example 2-4 and Comparative Example 1-2 are compared, the non-aqueous electrolyte battery containing the same (1a-Cis) and VEC is the non-aqueous electrolyte battery containing only the same (1a-Cis). It was confirmed that the effect was higher.
- Example 2-4 was compared with Comparative Example 2-2, and Example 2-16 was compared with Comparative Example 2-3, a non-aqueous system containing a cis-constant difluoroionic complex (1a-Cis) and VEC It was confirmed that the electrolyte battery was more effective than the nonaqueous electrolyte battery containing the trans-conformation difluoroionic complex (1a-Trans) and VEC.
- This is similar to Examples 1-1 to 1-11 and Examples 1-16 described above, and the non-aqueous electrolyte difluoroionic complex (1a-Cis) of the present invention and unsaturated such as VEC.
- these additives are reduced and decomposed on the negative electrode in the order of the same (1a-Cis) and VEC (or EEC) at the time of charge in the first cycle. ) Seems to form.
- Example 2-1 to Example 2-11 are compared, the effects of the difluoroionic complex (1a-Cis) and VEC are slightly increased even when the respective contents are 0.05% by mass. It was confirmed that the ionic complex content increased as it increased from 0.05% by mass to 0.1, 0.5, and 1.0% by mass.
- Example 2-5 When the content of the difluoroionic complex (1a-Cis) is 3.0% by mass (Example 2-5), the effect is slightly smaller than when the content is 1.0% by mass (Example 2-4). In the case of 5.0% by mass (Example 2-6), the effect was greatly reduced compared to 1.0% by mass. This is because, as in Examples 1-1 to 1-11 described above, when the content of the difluoroionic complex (1a-Cis) reaches 3.0% by mass or more, the viscosity of the non-aqueous electrolyte increases. It is expected that the movement of the cation in the non-aqueous electrolyte battery is hindered and the battery performance may be deteriorated.
- the ratio of the trans-conformation difluoroionic complex (1a-Trans) to the cis-conformation difluoroionic complex (1a-Cis), that is, the difluoroionic complex (1-Trans) / difluoroionic complex (1 -Cis) increased from 0.002 to 0.005, 0.01, the discharge capacity after storage at 60 ° C. (0 ° C. without adversely affecting the discharge capacity after 60 ° C. long-term cycle (0 ° C.) It was confirmed that there was a tendency to improve somewhat.
- the discharge capacity after long-term cycle at 60 ° C (0 ° C) and 5C It was confirmed that there was a tendency to further improve the discharge capacity (0 ° C.) after storage at 60 ° C.
- the complex (1-Cis) mass ratio
- Example 2-18 to Example 2-31 Further, as shown in Example 2-18 to Example 2-31, the cis-conformation difluoroionic complex (1a-Cis) of Synthesis Example 1 and the cis-conformation difluoroionic complex of Synthesis Example 3 ( 1b-Cis), VEC and EEC, the trans-conformation difluoroionic complex (1a-Trans) of Synthesis Example 1 and the trans-conformation difluoroionic complex (1b-Trans) of Synthesis Example 3, and shown in Synthesis Example 2
- the non-aqueous electrolyte solution containing a compound selected from four groups of the tetrafluoroionic complex (5a-Tetra) and the tetrafluoroionic complex (5b-Tetra) of Synthesis Example 5 is used for the tetrafluoroionic complex (5a -Tetra) and (5b-Tetra) free non-aqueous electrolytes (Examples 2-12 to 2-14) and trans-conformation difluoroi
- Non-aqueous electrolyte No. 1 of the present invention As for 3-1 to 3-28, the above-mentioned non-aqueous electrolyte No. Prepared in the same procedure as 1-1 to 1-41. Specifically, EC and EMC (volume ratio 1: 2) as non-aqueous solvents and LiPF 6 as an electrolyte were dissolved and prepared so as to have a concentration of 1 mol / L, and then various ionic complexes / EMC solutions according to the present invention. Or the compound of the above-mentioned (II) group, the following non-aqueous electrolyte solution No. 3-1 to 3-28 were prepared.
- Comparative electrolyte No. Preparation of 3-1 Comparative electrolyte No. In the same procedure and composition as in 1-4, as described in Table 5 below, by adding 2.0 mass% of FEC instead of VC, comparative electrolyte No. 3-1 was prepared.
- Comparative electrolyte No. Preparation of 3-2 Comparative electrolyte No.
- Comparative electrolyte No. In the same procedure and composition as in 1-5, as described in Table 5 described later, 2.0 mass% of FEC was added instead of VC, and (1a-Trans) of Synthesis Example 1 was added in Table 5 described later. By adding the predetermined amount described in the above, comparative electrolyte No. 3-2 was prepared.
- Comparative electrolyte No. Preparation of 3-3 Comparative electrolyte No. In the same procedure and composition as in 1-6, as described in Table 5 below, 2.0 mass% of FEC was added instead of VC, and (1a-Trans) of Synthesis Example 1 was further added. (5a-Tetra) was added in a predetermined amount as described in Table 5 below, so that the comparative electrolyte No. 3-3 was prepared.
- Example 3-4 shows that the nonaqueous electrolyte battery containing the same (1a-Cis) and FEC is the nonaqueous electrolyte battery containing only the same (1a-Cis). It was confirmed that the effect was higher.
- Example 3-4 and Comparative Example 3-2 were compared, and Example 3-16 and Comparative Example 3-3 were compared, a non-aqueous system containing a cis-constant difluoroionic complex (1a-Cis) and FEC It was confirmed that the electrolyte battery was more effective than the nonaqueous electrolyte battery containing the trans-conformation difluoroionic complex (1a-Trans) and FEC.
- the non-aqueous electrolyte solution of the present invention contains a difluoroionic complex (1a-Cis) and a carbonate containing a fluorine atom, such as FEC, so that these additives are difluoroionic complex ( 1a-Cis) and FEC (or trans-DFEC) in order of reductive decomposition on the negative electrode to form a stable coating (SEI) on the negative electrode surface.
- a-Cis difluoroionic complex
- FEC trans-DFEC
- Example 3-1 Compared Example 3-1 to Example 3-11, the effects of the difluoroionic complex (1a-Cis) and FEC are low addition amounts (for example, 0.05% by mass) of the respective contents. Even in the case, the difference could be confirmed, and it was confirmed that the content of (1a-Cis) increased as the content increased from 0.05% by mass to 0.1, 0.5, and 1.0% by mass.
- Example 3-5 When the content of the difluoroionic complex (1a-Cis) is 3.0% by mass (Example 3-5), the effect is slightly smaller than when the content is 1.0% by mass (Example 3-4). In the case of 5.0% by mass (Example 3-6), the effect was greatly reduced compared to 1.0% by mass. This is because, as in Examples 1-1 to 1-11 described above, when the content of the difluoroionic complex (1a-Cis) reaches 3.0% by mass or more, the viscosity of the non-aqueous electrolyte increases. It is expected that the movement of the cation in the non-aqueous electrolyte battery is hindered and the battery performance may be deteriorated.
- the ratio of the trans-conformation difluoroionic complex (1a-Trans) to the cis-conformation difluoroionic complex (1a-Cis), that is, the difluoroionic complex (1-Trans) / difluoroionic complex (1 -Cis) increased from 0.002 to 0.005, 0.01, the discharge capacity after storage at 60 ° C. (0 ° C. without adversely affecting the discharge capacity after 60 ° C. long-term cycle (0 ° C.) It was confirmed that there was a tendency to improve somewhat.
- the ratio of the tetrafluoroionic complex (5a-Tetra) to the difluoroionic complex (1a-Cis) in cis conformation that is, the tetrafluoroionic complex (5a-Tetra) / difluoroionic complex (1-Cis)
- Discharge capacity after 60 ° C storage without adversely affecting 60 ° C long-term cycle discharge capacity (0 ° C) as (mass ratio) increases from 0.07 to 0.12, 0.20 The tendency which (0 degreeC) improves has been confirmed.
- Non-aqueous electrolyte No. 1 of the present invention Non-aqueous electrolyte No. 1 of the present invention.
- non-aqueous electrolyte No. Prepared in the same procedure as 1-1 to 1-41.
- EC and EMC volume ratio 1: 2 as non-aqueous solvents and LiPF 6 as an electrolyte were dissolved and prepared so as to have a concentration of 1 mol / L, and then various ionic complexes / EMC solutions according to the present invention.
- the compound of the above-mentioned (II) group the following non-aqueous electrolyte solution No. 4-1 to 4-20 were prepared.
- Comparative electrolyte No. Preparation of 4-1 Comparative electrolyte No. In the same procedure and composition as in 1-4, as described in Table 7 below, 0.5% by mass of 1,6-DICNH was added instead of VC, so that the comparative electrolyte No. 4-1 was prepared.
- Comparative electrolyte No. Preparation of 4-2 Comparative electrolyte No. As described in Table 7 below, in the same procedure and composition as 1-6, 0.5% by mass of 1,6-DICNH was added instead of VC, and (1a-Trans) of Synthesis Example 1 was further added. By adding a predetermined amount of (5a-Tetra) of Synthesis Example 2 described in Table 7 below, the comparative electrolyte No. 4-2 was prepared.
- Example 4-1 to Example 4-20 and Comparative Example 4-1 Comparative Example 4-2-Production and Evaluation of Nonaqueous Electrolyte Battery
- the test NMC positive electrode the test graphite negative electrode
- cellulose In an aluminum laminate exterior cell (capacity 30 mAh) provided with a separator, the nonaqueous electrolyte solution No. 4-1 to 4-20, comparative electrolyte No. 4-1 and 4-2 were impregnated, and non-aqueous electrolyte batteries according to Example 4-1 to Example 4-20, Comparative Example 4-1, and Comparative Example 4-2 were produced.
- Examples 4-1 to 4-20 are the same as in Example 3-1 to Example 3-28 as the compounds of Group (I) (1a-Cis) of Synthesis Example 1. Or (1b-Cis) of Synthesis Example 3 and 1,6-DICNH or VC as a compound of Group (II), and (1a-Trans) of Synthesis Example 1 as a compound of Group (III) (1b-Trans) of Synthesis Example 3 and a compound selected from the tetrafluoroionic complex (5a-Tetra) shown in Synthesis Example 2 and (5b-Tetra) of Synthesis Example 5 as a compound of (IV) group
- a non-aqueous electrolyte that can be used, the discharge capacity after a 60 ° C. long-term cycle (0 ° C.), 5C rate characteristics (25 ° C.), and the discharge capacity after 60 ° C. storage (in comparison with Comparative Examples 4-1 and 4-2) 0 ° C) is confirmed to improve. It was.
- Positive electrode active materials LiNi 1/3 Mn 1/3 Co 1/3 O used in the non-aqueous electrolyte batteries according to Examples 1-1 to 1-41 and Comparative Examples 1-1 to 1-6 described above. 2 (NMC)
- NMC lithium / nickel / cobalt / aluminum composite oxide LiNi 0.85 Co 0.10 Al 0.05 O 2
- NCA positive electrode LiNi 0.85 Co 0.10 Al 0.05 O 2 (NCA) powder (manufactured by Toda Kogyo Co., Ltd.) and acetylene black (conductive agent) are dry-mixed and uniformly in NMP in which PVDF as a binder is dissolved in advance.
- NCA mixture paste was prepared by adding NMP for viscosity adjustment. This paste was applied on an aluminum foil (current collector), dried and pressurized, and then a test NCA positive electrode processed into a predetermined size was obtained.
- the charge upper limit voltage of 4.3 V was changed to 4.2 V in the initial charge / discharge of conditioning at an environmental temperature of 25 ° C., and the 0.1 C rate (3 mA ) At a constant current and a constant voltage, and discharge at a constant current of 0.2 C (6 mA) up to a discharge end voltage of 3.0 V. Thereafter, the charge upper limit voltage 4.3 V is changed to 4.2 V, and the 0.2 C rate is reached.
- a charge / discharge cycle in which the battery was charged at a constant current and a constant voltage at (6 mA) and discharged at a 0.2 C rate (6 mA) constant current to a discharge end voltage of 3.0 V was repeated three times.
- Example 5-1 and Example 5-5, Example 5-9 and Example 5-13 were compared with Comparative Example 5-2, the compounds of the same (1a-Cis) and (II) groups It was confirmed that the non-aqueous electrolyte battery containing each of the above had a higher effect than the non-aqueous electrolyte battery containing only (1a-Cis).
- Example 5-3 and Comparative Example 5-4 were compared, VC was used as a compound in the (1a-Cis) and (II) groups, and (5a-Tetra) was used as a compound in the (IV) group.
- the non-aqueous electrolyte battery containing a compound has three types: a trans-conformation difluoroionic complex (1a-Trans) and VC as a compound of group (II) and (5a-Tetra) as a compound of group (IV) It has been confirmed that the discharge capacity after long-term 60 ° C cycling (0 ° C), 5C rate characteristics (25 ° C), and discharge capacity after storage at 60 ° C (0 ° C) are improved as compared with non-aqueous electrolyte batteries containing these compounds It was.
- Examples 5-7 (compound (II) group; VEC) and Comparative Example 5-6, Example 5-11 ((II) group compound; FEC), Comparative Example 5-8 and Example 5 It was confirmed that -15 ((II) group compound; 1,6-DICNH) and Comparative Example 5-10 were similarly effective.
- each compound of (1a-Cis) and (II) group and (III) group Each compound (trans-conformation difluoroionic complex (1a-Trans)) and each compound of (IV) group (tetrafluoroionic complex (5a-Tetra)) is included in a predetermined amount
- non-aqueous electrolyte solutions not containing the same (5a-Tetra) Example 5-2, Example 5-6, Example 5-10, Example 5-14
- (1a -Discharge capacity (0 ° C) after 60 ° C long-term cycle and 5C compared to non-aqueous electrolytes not containing (Trans) Example 5-3, Example 5-7, Example 5-11, Example 5-15
- Rate characteristics (25 ° C) and discharge capacity (0 ° C) after 60 ° C storage are improved That there is a direction it has been confirmed.
- Example 6-1 to Example 6-16 and Comparative Example 6-1 to Comparative Example 6-10 Provide and Evaluation of Nonaqueous Electrolyte Battery
- Examples 5-1 to 5-16 and Comparative Examples 5-1 to 5-5 described above are used.
- the positive electrode active material LiNi 0.85 Co 0.10 Al 0.05 O 2 (NCA)
- NCA positive electrode active material
- LiFePO 4 LiFePO 4
- the LFP positive electrode for a test was produced in the following procedures using (LFP) powder.
- LFP positive electrode LiFePO 4 (LFP) powder and acetylene black (conductive agent 1) and vapor grown carbon fiber (Showa Denko VGCF (registered trademark) -H) (conductive agent 2) are dry-mixed and PVDF as a binder
- conductive agent 1 LiFePO 4
- conductive agent 2 acetylene black
- vapor grown carbon fiber Showa Denko VGCF (registered trademark) -H)
- non-aqueous electrolyte battery Various non-aqueous electrolytes listed in Table 9 were placed in an aluminum laminate outer cell (capacity 30 mAh) comprising the above test LFP positive electrode, a test graphite negative electrode, and a separator made of a microporous polypropylene-polyethylene bilayer film. Examples 6-1 to 6-16 were impregnated with various comparative electrolytes, and the same procedures as in Examples 5-1 to 5-16 and Comparative examples 5-1 to 5-10 were performed. In addition, non-aqueous electrolyte batteries according to Comparative Examples 6-1 to 6-10 were obtained.
- charge / discharge cycles of charging with a constant current and constant voltage at a charge upper limit voltage of 3.6 V and a 0.2 C rate (6 mA) and discharging at a constant current of 0.2 C (6 mA) to a discharge end voltage of 2.0 V are performed three times. Repeated. After this conditioning, a charge / discharge test at an environmental temperature of 60 ° C. was performed. Charging is performed at a constant current / constant voltage charging at a 3C rate (90 mA) up to a charging upper limit voltage of 3.6 V, and discharging is performed at a charging / discharging cycle in which discharging is performed at a 3C rate (90 mA) constant current up to a discharge end voltage of 2.0 V.
- the non-aqueous electrolyte battery was cooled to 25 ° C., discharged to 2.0 V again, and then charged with constant current and constant voltage to 3.6 V at 0 ° C. and a 0.2 C rate. Furthermore, the discharge is performed at a constant current at a 5 C rate (150 mA) up to a discharge end voltage of 2.0 V while maintaining the temperature at 0 ° C., and the capacity obtained at this time is expressed as a low-temperature characteristic (0 ° C.) after a 60 ° C. long-term cycle. did.
- ⁇ Evaluation 2> 5C rate characteristics after 60 ° C. 500 cycles After performing 500 cycles at the environmental temperature of 60 ° C. in the above evaluation 1, the non-aqueous electrolyte battery is subsequently cooled to 25 ° C. and discharged to 2.0 V again. Then, constant current and constant voltage charging was performed up to 3.6 V at 25 ° C. and 5 C rate. Furthermore, the discharge is performed at a constant current of 5 C rate (150 mA) up to a discharge end voltage of 2.0 V while maintaining the temperature at 25 ° C., and the capacity obtained at this time is the 5 C rate characteristic after a long cycle of 60 ° C. (25 ° C.). It was.
- the discharge was performed at a constant current at a 5C rate (150 mA) up to a discharge end voltage of 2.0 V while maintaining the temperature at 0 ° C., and the capacity obtained at this time was defined as a low temperature characteristic (0 ° C.) after storage at 60 ° C. .
- Examples 6-1 to 6-16 showed the same tendency as Examples 5-1 to 5-16. That is, even when LFP is used as the positive electrode active material in place of NCA, (1a-Cis) of Synthesis Example 1 and VC as the compound of (II) group are used as the compounds of group (I) according to the examples.
- Example 7-1 to Example 7-10 and Comparative Example 7-1 to Comparative Example 7-15-Preparation of Nonaqueous Electrolyte [Nonaqueous electrolyte No. 7-1 to 7-5, comparative electrolyte No. Preparation of 7-2 to 7-8] FEC (volume ratio: 25: 70: 5 / mass ratio: 29), which was previously heated and dissolved in a nitrogen atmosphere dry box having a dew point of -50 ° C. 7: 63.6: 6.7), LiPF 6 as an electrolyte is dissolved and prepared to a concentration of 1.2 mol / L, and then various ionic complexes / EMC solutions according to the present invention are used.
- the non-aqueous electrolyte solution No. 1 of the present invention is added. 7-1 to 7-5, comparative electrolyte No. 7-2 to 7-8 were prepared. That is, (1a-Cis) of Synthesis Example 1 which is a compound of the group (I), and VC, VEC, EEC, 2-allyl succinic anhydride, 1,6-DICNH, (Compound 2 of the group (II)) ( The compounds selected from the four groups of (1a-Trans) of Synthesis Example 1 as the compound of Group III) and the tetrafluoroionic complex (5a-Tetra) of Synthesis Example 2 as the compound of Group (IV) are respectively shown below. By adding the predetermined amount described in Table 12, the non-aqueous electrolyte solution No. 7-1 to 7-5, comparative electrolyte No. 7-2 to 7-8 were prepared.
- FEC volume ratio 20: 70: 10 / mass ratio 23
- II compound of the above-mentioned group
- LiPF 6 as an electrolyte is dissolved and prepared so as to have a concentration of 1.2 mol / L, and then various ionic complexes / EMC solutions according to the present invention and the above-mentioned ( II) Group non-aqueous electrolyte solution No. 2 of the present invention is added. 7-6 to 7-10, comparative electrolyte No. 7-9 to 7-15 were prepared.
- (1a-Cis) of Synthesis Example 1 which is a compound of the group (I), and VC, VEC, EEC, 2-allyl succinic anhydride, 1,6-DICNH, (Compound 2 of the group (II))
- the compounds selected from the four groups of (1a-Trans) of Synthesis Example 1 as the compound of Group III) and the tetrafluoroionic complex (5a-Tetra) of Synthesis Example 2 as the compound of Group (IV) are respectively shown below.
- the non-aqueous electrolyte solution No. 7-6 to 7-10, comparative electrolyte No. 7-9 to 7-15 were prepared.
- the positive electrode active material LiNi 0.85 Co 0.10 Al 0.05 O used in the non-aqueous electrolyte batteries according to Examples 5-1 to 5-16 and Comparative Examples 5-1 to 5-10 described above. 2 (NCA)) instead of 0.5 [LiNi 0.5 Mn 0.5 O 2 ] ⁇ 0.5 [Li 2 MnO 3 ] (OLO) as a lithium-excess layered transition metal oxide having a layered rock salt structure -1)
- NCA Nonaqueous Electrolyte Battery
- non-aqueous electrolyte battery Various non-aqueous systems as described in Table 12 were provided in an aluminum laminate outer cell (capacity 30 mAh) comprising the test OLO-1 positive electrode, the test graphite negative electrode, and a separator made of a microporous polypropylene-polyethylene bilayer film.
- Examples 7-1 to 7 were impregnated with an electrolytic solution and various comparative electrolytic solutions, respectively, in the same procedure as in Examples 5-1 to 5-16 and Comparative Examples 5-1 to 5-10.
- -10 and non-aqueous electrolyte batteries according to Comparative Examples 7-1 to 7-15 were obtained.
- Example 7-1 to 7-10 Comparative Examples 7-1 to 7-15-Evaluation of prototype cell
- Discharging was performed at a constant current of 0.1 C (3 mA) up to 5V. After that, charge / discharge cycles of charging at a constant current and constant voltage at a charging upper limit voltage of 4.4 V and a 0.1 C rate (3 mA) and discharging at a constant current of 0.1 C (3 mA) up to a discharge end voltage of 2.5 V are performed five times. Repeated. After this conditioning, the battery is charged at a constant current and constant voltage at an ambient temperature of 25 ° C. at a charge upper limit voltage of 4.6 V and a 0.1 C rate (3 mA), and at a 0.2 C rate (6 mA) constant current up to a discharge end voltage of 2.5 V. The charge / discharge cycle for discharging was repeated 3 times.
- a charge / discharge test at an environmental temperature of 60 ° C. was performed. Charging is performed at a constant current / constant voltage charge at a 1C rate (30 mA) up to a charge upper limit voltage of 4.6V, and discharging is performed at a charge / discharge cycle in which discharge is performed at a 2C rate (60 mA) constant current up to a discharge end voltage of 2.5V. Repeated 300 times. Subsequently, the non-aqueous electrolyte battery was cooled to 25 ° C. and discharged again to 2.5 V, and then constant current and constant voltage charging was performed up to 4.6 V at 0 ° C. and 0.2 C rate.
- the battery was discharged at a constant current at a 3C rate (90 mA) up to a discharge end voltage of 2.5 V while maintaining the temperature at 0 ° C., and the capacity obtained at this time was defined as a low temperature characteristic (0 ° C.) after a 60 ° C. long-term cycle.
- the non-aqueous electrolyte battery is subsequently cooled to 25 ° C. and discharged to 2.5 V again.
- constant current and constant voltage charging was performed up to 4.6 V at 25 ° C. and a 0.1 C rate.
- the discharge is performed at a constant current at a 3C rate (90 mA) up to a discharge end voltage of 2.5 V while maintaining the temperature at 25 ° C. It was.
- the discharge was performed at a constant current at a 3C rate (90 mA) up to a final discharge voltage of 2.5 V while maintaining the temperature at 0 ° C., and the capacity obtained at this time was defined as a low temperature characteristic (0 ° C.) after storage at 60 ° C. .
- the positive electrode contains at least one metal of nickel, manganese and cobalt and has a layered structure, a lithium transition metal composite oxide having a spinel structure, a lithium manganese composite oxide having a spinel structure, and a lithium-containing olivine-type phosphorus. It was confirmed that the non-aqueous electrolyte solution of the present invention showed a good effect in both cases of using an iron salt and a lithium-excess layered transition metal oxide having a layered rock salt type structure.
- the non-aqueous electrolyte of the present invention and a battery using the non-aqueous electrolyte do not depend on a specific positive electrode, and can exhibit high output characteristics at a low temperature even when the battery is used to some extent, and can be stored at a high temperature. It is clear that sufficient performance can be exhibited at a low temperature even after being applied.
- Example 8-1 to Example 8-24, and Comparative Example 8-1 to Comparative Example 8-14-Production and Evaluation of Nonaqueous Electrolyte Battery instead of the negative electrode active material (graphite powder) used in the non-aqueous electrolyte batteries according to Examples 1-1 to 1-41 and Comparative Examples 1-1 to 1-6 described above, a lattice plane in X-ray diffraction As a carbon material having a d value of (002 face) exceeding 0.340 nm, an amorphous carbon negative electrode for testing was prepared by the following procedure using amorphous carbon powder.
- amorphous carbon powder Kaboha Co., Ltd. Carbotron (registered trademark) P is used, and PVDF as a binder is uniformly dispersed and mixed in NMP previously dissolved, and further NMP for viscosity adjustment is added.
- an amorphous carbon mixture paste was prepared. This paste was applied onto a copper foil (current collector), dried and pressurized, and then an amorphous carbon negative electrode for testing processed into a predetermined size was obtained.
- Non-aqueous electrolyte No. 1 of the present invention. 8-1 to 8-24, and comparative electrolyte No. 8-2 to 8-14 were prepared.
- (1a-Cis) of Synthesis Example 1 which is a compound of the aforementioned group (I), VC, VEC, EEC, FEC, 2-allyl succinic anhydride, 1,6-DICNH as a compound of the aforementioned group (II),
- the non-aqueous electrolyte solution No. 8-1 to 8-24, and comparative electrolyte No. 8-2 to 8-14 were prepared.
- Non-aqueous electrolyte battery An aluminum laminate outer cell (capacity 30 mAh) comprising the above test NMC positive electrode, a test amorphous carbon negative electrode, and a separator made of a microporous polypropylene-polyethylene two-layer film was used.
- a nonaqueous electrolyte battery according to Examples 8-1 to 8-24 and Comparative examples 8-1 to 8-14 was obtained by impregnation with an aqueous electrolyte and various comparative electrolytes, respectively.
- the battery was charged with a constant current and a constant voltage at a charge upper limit voltage 4.2 V 0.1 C rate (3 mA), and 0 to a discharge end voltage 2.7 V.
- Discharge at a constant current of 2 C rate (6 mA) then charge at a constant current and a constant voltage at a charge upper limit voltage of 4.2 V and a 0.2 C rate (6 mA), and reach a final discharge voltage of 2.7 V at a 0.2 C rate (6 mA).
- the charge / discharge cycle for discharging at a constant current was repeated three times.
- the discharge end voltage 3.0V was changed to 2.7V, and the constant current was constant up to 4.2V at 0 ° C and 0.2C rate.
- the discharge end voltage 3.0 V was changed to 2.7 V, and the same evaluation was made except that the discharge was changed to a constant current at a 5 C rate (150 mA). .
- the capacity obtained at this time was defined as a low temperature characteristic (0 ° C.) after a 60 ° C. long-term cycle.
- Example 9-1 to Example 9-24 and Comparative Example 9-1 to Comparative Example 9-14-Production and Evaluation of Nonaqueous Electrolyte Battery An artificial graphite negative electrode instead of the negative electrode active material (amorphous carbon powder) used in the non-aqueous electrolyte batteries according to Examples 8-1 to 8-24 and Comparative Examples 8-1 to 8-14 described above
- a negative electrode for testing artificial graphite + natural graphite mixed was prepared by the following procedure using a negative electrode active material obtained by mixing a graphite with natural graphite.
- This paste was applied on a copper foil (current collector), dried and pressurized, and then a test (artificial graphite + natural graphite mixed) negative electrode processed into a predetermined size was obtained.
- Table 16 shows an aluminum laminate outer cell (capacity 30 mAh) including the above test NMC positive electrode, a test (artificial graphite + natural graphite mixed) negative electrode, and a separator made of a microporous polypropylene-polyethylene bilayer film. Examples were impregnated with various non-aqueous electrolytes and various comparative electrolytes, respectively, in the same procedure as in Examples 6-1 to 6-16 and Comparative Examples 6-1 to 6-10. Non-aqueous electrolyte batteries according to 9-1 to 9-24 and Comparative Examples 9-1 to 9-14 were obtained.
- Examples 9-1 to 9-24 showed the same tendency as Examples 8-1 to 8-24. That is, even when a powder obtained by mixing artificial graphite and natural graphite is used as the negative electrode active material, (1a-Cis) of Synthesis Example 1 and (II) VC, VEC, EEC, FEC, 2-allyl succinic anhydride, and 1,6-DICNH are used in combination as the compound, and (1a-Trans) of Synthesis Example 1 as a compound of Group (III), and (IV) By using a non-aqueous electrolyte solution that can contain a compound selected from the tetrafluoroionic complex (5a-Tetra) shown in Synthesis Example 2 as a compound of the group, 60% more than Comparative Examples 9-1 to 9-14. It was confirmed that the discharge capacity after long-term cycle at 0 ° C. (0 ° C.), the 5C rate characteristic (25 ° C.) and the discharge capacity after storage at 60 ° C. (0
- LiPF 6 as an electrolyte is dissolved and prepared so as to have a concentration of 1.2 mol / L, and then various ionic complexes / EMC solutions according to the present invention and the above-mentioned ( II) Group non-aqueous electrolyte solution No. 2 of the present invention is added. 10-1 to 10-5, and comparative electrolyte No. 10-2 to 10-8 were prepared.
- (1a-Cis) of Synthesis Example 1 which is a compound of the group (I), and VC, VEC, EEC, 2-allyl succinic anhydride, 1,6-DICNH, (Compound 2 of the group (II))
- the compounds selected from the four groups of (1a-Trans) of Synthesis Example 1 as the compound of Group III) and the tetrafluoroionic complex (5a-Tetra) of Synthesis Example 2 as the compound of Group (IV) are respectively shown below.
- the non-aqueous electrolyte solution No. 10-1 to 10-5, and comparative electrolyte No. 10-2 to 10-8 were prepared.
- Nonaqueous electrolyte No. 10-6 to 10-10 comparative electrolyte No. Preparation of 10-9 to 10-15
- FEC volume ratio 15: 70: 15 / mass ratio 17
- EC volume ratio 15: 70: 15 / mass ratio 17
- LiPF 6 as an electrolyte was dissolved and prepared to a concentration of 1.2 mol / L, and then various ionic complexes / EMC solutions according to the present invention and the above-mentioned ( II) Group non-aqueous electrolyte solution No. 2 of the present invention is added. 10-6 to 10-10 and comparative electrolyte No. 10-9 to 10-15 were prepared.
- (1a-Cis) of Synthesis Example 1 which is a compound of the group (I), and VC, VEC, EEC, 2-allyl succinic anhydride, 1,6-DICNH, (Compound 2 of the group (II))
- the compounds selected from the four groups of (1a-Trans) of Synthesis Example 1 as the compound of Group III) and the tetrafluoroionic complex (5a-Tetra) of Synthesis Example 2 as the compound of Group (IV) are respectively shown below.
- the non-aqueous electrolyte solution No. 10-6 to 10-10 and comparative electrolyte No. 10-9 to 10-15 were prepared.
- Example 10-1 to Example 10-10 and Comparative Example 10-1 to Comparative Example 10-15 Provide and Evaluation of Nonaqueous Electrolyte Battery
- the negative electrode active material powder obtained by mixing artificial graphite and natural graphite
- a test SiO x negative electrode was prepared by the following procedure using a mixed powder of silicon oxide powder and massive artificial graphite powder as a negative electrode active material.
- SiO x negative electrode As the silicon oxide powder, silicon oxide powder disproportionated by heat treatment (SiO x (x is 0.3 to 1.6) manufactured by Sigma-Aldrich Japan, average particle size 5 ⁇ m), and bulk artificial graphite powder Using a mixed powder of MAG-D (particle size 20 ⁇ m or less) manufactured by Hitachi Chemical Co., Ltd., uniformly dispersing it in NMP in which PVDF, a binder, was previously dissolved, and adding ketjen black (conductive agent) and mixing Further, NMP for viscosity adjustment was added to prepare a SiO x mixture paste.
- SiO x silicon oxide powder disproportionated by heat treatment
- MAG-D particle size 20 ⁇ m or less
- This paste was applied on a copper foil (current collector), dried and pressurized, and then a test SiO x negative electrode processed into a predetermined size was obtained.
- the amount of the NMC positive electrode active material and the SiO x powder is adjusted so that the charge capacity of the SiO x negative electrode is larger than the charge capacity of the NMC positive electrode so that lithium metal does not deposit on the SiO x negative electrode during the charge.
- the coating amount was also adjusted.
- Non-aqueous electrolysis described in Table 18 were made on an aluminum laminate outer cell (capacity 30 mAh) comprising the above test NMC positive electrode, test SiO x negative electrode, and a separator made of a microporous polypropylene-polyethylene two-layer film.
- Examples 10-1 to 10- were impregnated with a liquid and various comparative electrolytes, respectively, in the same procedure as in Examples 9-1 to 9-24 and Comparative Examples 9-1 to 9-14. 10 and non-aqueous electrolyte batteries according to Comparative Examples 10-1 to 10-15 were obtained.
- the polypropylene side of the separator made of the microporous polypropylene-polyethylene bilayer film is arranged on the positive electrode side. Then, the positive electrode and the negative electrode were made to face each other to obtain a nonaqueous electrolyte battery.
- the charge / discharge cycle for discharging at a constant current (3 mA) was repeated 5 times.
- the battery was charged at a constant current and constant voltage at an ambient temperature of 25 ° C. at a charging upper limit voltage of 4.2 V and a 0.2 C rate (6 mA), and at a 0.2 C rate (6 mA) constant current up to a discharge end voltage of 2.5 V.
- the charge / discharge cycle for discharging was repeated 3 times. Thereafter, a charge / discharge test at an environmental temperature of 60 ° C.
- the battery was discharged at a constant current at a 3C rate (90 mA) up to a discharge end voltage of 2.5 V while maintaining the temperature at 0 ° C., and the capacity obtained at this time was defined as a low temperature characteristic (0 ° C.) after a 60 ° C. long-term cycle.
- the nonaqueous electrolyte battery is subsequently cooled to 25 ° C. and discharged to 2.5 V again.
- constant current and constant voltage charging was performed up to 4.2 V at a rate of 25 ° C. and a 0.1 C rate.
- the discharge is performed at a constant current at a 3C rate (90 mA) up to a discharge end voltage of 2.5 V while maintaining the temperature at 25 ° C. It was.
- the discharge was performed at a constant current at a 3C rate (90 mA) up to a final discharge voltage of 2.5 V while maintaining the temperature at 0 ° C., and the capacity obtained at this time was defined as a low temperature characteristic (0 ° C.) after storage at 60 ° C. .
- Example 10-1 to Example 10-10 For Example 10-1 to Example 10-10 in which a mixed powder of silicon oxide powder and massive artificial graphite powder was used instead of the powder obtained by mixing artificial graphite and natural graphite as the negative electrode active material, From the results, the following was confirmed.
- the compound of (III) group is selected from four groups of (1a-Trans) of Synthesis Example 1 and the compound of (IV) group is a tetrafluoroionic complex (5a-Tetra) shown in Synthesis Example 2
- the discharge capacity after long-term 60 ° C cycling (0 ° C), 3C rate characteristics (25 ° C), and after 60 ° C storage compared to Comparative Examples 10-1 to 10-15 It was confirmed that all the discharge capacities (0 ° C.) were improved.
- Negative electrode active material mixed powder of silicon oxide powder and massive artificial graphite powder used in the non-aqueous electrolyte batteries according to Examples 10-1 to 10-10 and Comparative Examples 10-1 to 10-15 described above Instead of, a Si negative electrode for testing was prepared by the following procedure using Si powder as the negative electrode active material.
- the amount of the NMC positive electrode active material and the Si powder is adjusted so that the charge capacity of the Si negative electrode is larger than the charge capacity of the NMC positive electrode, and the coating amount is set so that lithium metal does not deposit on the Si negative electrode during the charge. Adjusted.
- non-aqueous electrolyte battery Various non-aqueous electrolytes listed in Table 18 were placed in an aluminum laminate outer cell (capacity 30 mAh) comprising the above test NMC positive electrode, a test Si negative electrode, and a separator made of a microporous polypropylene-polyethylene bilayer film. Examples 11-1 to 11-10 were impregnated with various comparative electrolytes, respectively, in the same procedure as in Examples 10-1 to 10-10 and Comparative Examples 10-1 to 10-15 described above. In addition, non-aqueous electrolyte batteries according to Comparative Examples 11-1 to 11-15 were obtained.
- Example 11-1 to 11-10 and Comparative Examples 11-1 to 11-15-Evaluation of Nonaqueous Electrolyte Battery Similar to the non-aqueous electrolyte batteries according to Examples 10-1 to 10-10 and Comparative Examples 10-1 to 10-15, the following evaluations were performed.
- Example 12-1 to Example 12-12 and Comparative Example 12-1 to Comparative Example 12-8—Preparation of Nonaqueous Electrolyte) [Nonaqueous electrolyte No. 12-1 to 12-12, comparative electrolyte No. Preparation of 12-2 to 12-8] Concentrations of LiPF 6 and LiBF 4 as electrolytes in a non-aqueous solvent of PC and EMC (volume ratio 30: 70 / mass ratio 33.8: 66.2) in a nitrogen atmosphere dry box with a dew point of ⁇ 50 ° C.
- Li 4 Ti 5 O 12 Using the (LTO) powder as a negative electrode active material, a test LTO alloy negative electrode was prepared by the following procedure.
- Non-aqueous electrolyte battery Various non-aqueous electrolytes shown in Table 21 and various comparative electrolytes are placed on an aluminum laminate outer cell (capacity 30 mAh) including the test NMC positive electrode, the test LTO negative electrode, and a separator made of cellulose. Examples 12-1 to 12-12 and Comparative Examples 12-1 to 12-12 were impregnated in the same procedure as in Examples 6-1 to 6-16 and Comparative Examples 6-1 to 6-10. A non-aqueous electrolyte battery according to 12-8 was obtained.
- the battery was discharged at a constant current of 0.1 C rate (3 mA), and then charged at a constant current and constant voltage at a charging upper limit voltage of 2.8 V and a 0.1 C rate (3 mA). 3 mA)
- the charge / discharge cycle for discharging at a constant current was repeated three times. After this conditioning, the battery was charged at a constant current and constant voltage at an ambient temperature of 25 ° C. at a charge upper limit voltage of 2.8 V and a 0.2 C rate (6 mA), and at a 0.2 C rate (6 mA) constant current up to a discharge end voltage of 1.5 V.
- the charge / discharge cycle for discharging was repeated 3 times. Thereafter, a charge / discharge test at an environmental temperature of 60 ° C. was performed.
- Charging is performed at a constant current / constant voltage charge at a 2C rate (30 mA) up to an upper limit voltage of 2.8 V, and a charge / discharge cycle of discharging at a constant current of 2 C rate (60 mA) at a discharge end voltage of 1.5 V is repeated 500 times. It was. Subsequently, the non-aqueous electrolyte battery was cooled to 25 ° C. and discharged again to 1.5 V, and then constant current and constant voltage charging was performed up to 2.8 V at 0 ° C. and 0.2 C rate.
- the battery was discharged at a constant current at a 5C rate (150 mA) up to a final discharge voltage of 1.5 V while maintaining the temperature at 0 ° C., and the capacity obtained at this time was defined as a low temperature characteristic (0 ° C.) after a 60 ° C. long-term cycle.
- the nonaqueous electrolyte battery is subsequently cooled to 25 ° C. and discharged to 1.5 V again. Then, constant current and constant voltage charging was performed up to 2.8 V at a rate of 25 ° C. and 0.1 C. Further, the battery was discharged at a constant current of 5 C rate (150 mA) up to a discharge end voltage of 1.5 V while maintaining the temperature at 25 ° C., and the capacity obtained at this time was defined as the 5 C rate characteristic (25 ° C.) after 60 ° C. long-term cycle.
- the battery was discharged at a constant current of 5 C rate (150 mA) up to a discharge end voltage of 1.5 V while maintaining the temperature at 0 ° C., and the capacity obtained at this time was defined as a low temperature characteristic (0 ° C.) after storage at 60 ° C.
- the carbon material in which the d value of the lattice plane (002 plane) in the X-ray diffraction exceeds 0.340 nm and the d value of the lattice plane (002 plane) in the X-ray diffraction are 0.340 nm or less Material, oxide of one or more metals selected from Si, Sn, Al, one or more metals selected from Si, Sn, Al, alloys containing these metals, or alloys of these metals or alloys with lithium, lithium
- the nonaqueous electrolytic solution of the present invention exhibits the same effects as those of Examples 1-1 to 1-47. That is, it is clear that the non-aqueous electrolyte solution of the present invention and the battery using the same have the effect of improving the cycle characteristics without depending on the specific negative electrode, like the above-described positive electrode.
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Abstract
Description
1サイクル目充電時に負極にリチウムカチオンが挿入される際に、負極とリチウムカチオン、又は負極と電解液溶媒が反応し、負極表面上に酸化リチウムや炭酸リチウム、アルキル炭酸リチウムを主成分とする被膜を形成する。この電極表面上の被膜はSolid Electrolyte Interface(SEI)と呼ばれ、溶媒の還元分解を抑制し電池性能の劣化を抑える等、その性質が電池性能に大きな影響を与えている。
このように、非水系溶媒の分解物の蓄積やガスの発生、負極材料の微粉化による悪影響などにより、負極へのリチウムの吸蔵及び放出がスムーズにできなくなり、結果としてサイクル特性などの電池特性の低下が著しいという問題を有している。
また特許文献5においては、ジイソシアネート化合物を含む電解液を用いた非水系電解質電池が開示されており、電池の長期保存信頼性などの向上を図る試みがなされている。
また、ビニレンカーボネートやフルオロエチレンカーボネートと、ジフルオロ(ビスオキサラト)リン酸リチウムとを所定量含有することで低温での入出力特性を向上させる提案(特許文献10、特許文献11)、ジフルオロ(オキサラト-O,O’)ホウ酸リチウムやテトラフルオロ(オキサラト-O,O’)リン酸リチウムと、添加剤としてビニレンカーボネートやビニルエチレンカーボネートなどの不飽和化合物の炭酸エステルとを含有する電解液を用いることで、電池容量、サイクル特性及び保存特性などの電池特性を向上させる提案(特許文献12)が開示されている。
また、特許文献17には、トリス(オキサラト)リン酸リチウムの製造方法が開示されている。
特許文献18には、炭素-窒素不飽和結合を有する化合物の1つである、ジイソシアネート化合物(ヘキサメチレンジイソシアネート)を、非水系電解液中に添加すると、サイクル特性や保存特性の向上が見られることが開示されている。
(I)一般式(1-Cis)で示されるシス型の立体配座をとるジフルオロイオン性錯体(1-Cis)と、
(II)不飽和結合を有するカーボネート、フッ素原子を有するカーボネート、酸無水物、及びイソシアナト基を有する化合物からなる群より選ばれる少なくとも1種の化合物と、
を含むことを特徴とする非水系電解液を提供するものである。
本発明の非水系電解液は、非水有機溶媒と該非水有機溶媒に溶解される電解質とを含み、さらに一般式(1-Cis)で示される、シス型の立体配座をとるジフルオロイオン性錯体(1-Cis)と、下記(II)の化合物からなる群から選ばれる少なくとも1種の化合物とを含むことを特徴とする。
Xは酸素原子又は-N(R1)-である。Nは窒素原子であり、R1は炭素数1~10のヘテロ原子やハロゲン原子を有していてもよい炭化水素基(炭素数が3以上の場合にあっては、分岐鎖又は環状構造のものも使用できる)である。
Xが-N(R1)-でpが0の場合、XとWは直接結合し、その際は下記一般式(2)~(4)のような構造をとることもできる。直接結合が二重結合となる下記一般式(3)の場合、R1は存在しない。
Wは炭素数1~10のヘテロ原子やハロゲン原子を有していてもよい炭化水素基(炭素数が3以上の場合にあっては、分岐鎖あるいは環状構造のものも使用できる)、又は-N(R2)-を表す。このとき、R2は水素原子、アルカリ金属、炭素数1~10のヘテロ原子やハロゲン原子を有していてもよい炭化水素基を表す。炭素数が3以上の場合にあっては、R2は分岐鎖又は環状構造をとることもできる。
pは0又は1、qは0~2の整数、rは0~2の整数をそれぞれ表す。また、p+r≧1である。
(1a)M=P、X=O、Y=C、p、q、t=1、r=0
(1b)M=P、X=O、W=C(CF3)2、p、q=0、r、t=1
(1c)M=Si、X=O、Y=C、p、q=1、t=2、r=0
(1d)M=P、X=N(R1)、Y=C、R1=CH3、p、q、t=1、r=0
(II-1)一般式(II-1a)及び/又は(II-1b)で示される不飽和結合を有するカーボネート。
(II-2)一般式(II-2a)で示されるフッ素原子を有するカーボネート。
(II-3)一般式(II-3a)で示される酸無水物。
(II-4)一般式(II-4a)で示されるイソシアナト基を有する化合物。
これらは単独でも2種以上を適宜組み合わせて用いてもよい。
但し、R7~R10のうち少なくとも一つにフッ素原子を有する。R7~R10はエーテル結合を含んでもよい。)
(Tetra-a)M=P、X=O、Y=C、p、q、t=1、r=0
(Tetra-b)M=P、X=O、W=C(CF3)2、p、q=0、r、t=1
(Tetra-c)M=Si、X=O、Y=C、p、q=1、t=2、r=0
(Tetra-d)M=P、X=N(R1)、Y=C、R1=CH3、p、q、t=1、r=0
負極とジフルオロリン酸錯体(シス、トランス)の還元反応の開始について、まずは立体的要因から考察する。ジフルオロリン酸錯体が負極から電子を受け取り、還元が最初に進行する箇所はF以外の配位子部分である。(1aであればカルボニル基の炭素)そのため、還元が進行するためにはFが結合していない面から負極に接近する必要がある。トランス体はFが分子の上と下に結合しているため、必然的に右、又は左から、すなわち上下180度を除いた左右の計180度の範囲の中で分子が電極に接近した場合にのみ還元反応が進行する。それに対してシス体は、Fの位置が同一方向にまとまっているため、その逆方向の200~250度の範囲の中で接近できれば良く、還元反応が進行する確率がトランス体よりも高くなる。
なお、この非水系電解液と、リチウムイオンやナトリウムイオンを始めとするアルカリ金属イオン、又はアルカリ土類金属イオンが可逆的に挿入-脱離可能な負極材料と、リチウムイオンやナトリウムイオンを始めとするアルカリ金属イオン、又はアルカリ土類金属イオンが可逆的に挿入-脱離可能な正極材料を用いる電気化学デバイスを非水系電解液電池と呼ぶ。
例えば、非水系溶媒中にまず全リチウム塩の10~35質量%の範囲を加えて溶解した後、次いで、更に全リチウム塩の10~35質量%の範囲を加えて、溶解する操作を2~9回実施し、最後に、残りのリチウム塩を徐々に加えて溶解することで、液温が40℃を越えないようにすることが好ましい。
特に、本発明の非水系電解液を調合する場合は、調合時の非水系電解液の液温上昇により、前記副反応が進行しやすくなるため、非水系電解液の液温が40℃を越えないように温度上昇を抑えることで、非水系電解液の劣化を防ぐことが可能となり、その品質を維持することが可能となる。
本発明の非水系電解液電池は、(ア)上記の非水系電解液と、(イ)正極と、(ウ)負極と、(エ)セパレータとを備える。
本発明の非水系電解液電池は、<1.非水系電解液>で説明した非水系電解液を備える。
(イ)正極は、少なくとも1種の酸化物及び/又はポリアニオン化合物を正極活物質として含むことが好ましい。
非水系電解液中のカチオンがリチウム主体となるリチウムイオン二次電池の場合、(イ)正極を構成する正極活物質は、充放電が可能な種々の材料であれば特に限定されるものでないが、例えば、(A)ニッケル、マンガン、コバルトの少なくとも1種以上の金属を含有し、かつ層状構造を有するリチウム遷移金属複合酸化物、(B)スピネル構造を有するリチウムマンガン複合酸化物、(C)リチウム含有オリビン型リン酸塩、及び(D)層状岩塩型構造を有するリチウム過剰層状遷移金属酸化物から少なくとも1種を含有するものが挙げられる。
正極活物質(A)ニッケル、マンガン、コバルトの少なくとも1種以上の金属を含有し、かつ層状構造を有するリチウム遷移金属複合酸化物としては、例えば、リチウム・コバルト複合酸化物、リチウム・ニッケル複合酸化物、リチウム・ニッケル・コバルト複合酸化物、リチウム・ニッケル・コバルト・アルミニウム複合酸化物、リチウム・コバルト・マンガン複合酸化物、リチウム・ニッケル・マンガン複合酸化物、リチウム・ニッケル・マンガン・コバルト複合酸化物等が挙げられる。また、これらリチウム遷移金属複合酸化物の主体となる遷移金属原子の一部を、Al、Ti、V、Cr、Fe、Cu、Zn、Mg、Ga、Zr、Si、B、Ba、Y、Sn等の他の元素で置換したものを用いても良い。
LiaNi1-b-cCobM1 cO2 (1-1)
LidNieMnfCogM2 hO2 (1-2)
正極活物質(B)スピネル構造を有するリチウムマンガン複合酸化物としては、例えば、一般式(1-3)で示されるスピネル型リチウムマンガン複合酸化物が挙げられる。
Lij(Mn2-kM3 k)O4 (1-3)
正極活物質(C)リチウム含有オリビン型リン酸塩としては、例えば一般式(1-4)で示されるものが挙げられる。
LiFe1-nM4 nPO4 (1-4)
正極活物質(D)層状岩塩型構造を有するリチウム過剰層状遷移金属酸化物としては、例えば一般式(1-5)で示されるものが挙げられる。
xLiM5O2・(1-x)Li2M6O3 (1-5)
(イ)正極は、正極集電体を有する。正極集電体としては、例えば、アルミニウム、ステンレス鋼、ニッケル、チタン又はこれらの合金等を用いることができる。
(イ)正極は、例えば正極集電体の少なくとも一方の面に正極活物質層が形成される。正極活物質層は、例えば、前述の正極活物質と、結着剤と、必要に応じて導電剤とにより構成される。
(ウ)負極は、負極活物質を含む。
非水系電解液中のカチオンがリチウム主体となるリチウムイオン二次電池の場合、(ウ)負極を構成する負極活物質としては、リチウムイオンのド-プ・脱ド-プが可能なものであり、例えば(E)X線回折における格子面(002面)のd値が0.340nm以下の炭素材料、(F)X線回折における格子面(002面)のd値が0.340nmを超える炭素材料、(G)Si、Sn、Alから選ばれる1種以上の金属の酸化物、(H)Si、Sn、Alから選ばれる1種以上の金属若しくはこれら金属を含む合金又はこれら金属若しくは合金とリチウムとの合金、及び(I)リチウムチタン酸化物から選ばれる少なくとも1種を含有するものが挙げられる。これら負極活物質は、1種を単独で用いることができ、2種以上を組合せて用いることもできる。
負極活物質(E)X線回折における格子面(002面)のd値が0.340nm以下の炭素材料としては、例えば熱分解炭素類、コークス類(例えばピッチコークス、ニードルコークス、石油コークス等)、グラファイト類、有機高分子化合物焼成体(例えばフェノール樹脂、フラン樹脂等を適当な温度で焼成し炭素化したもの)、炭素繊維、活性炭等が挙げられ、これらは黒鉛化したものでもよい。当該炭素材料は、X線回折法で測定した(002)面の面間隔(d002)が0.340nm以下のものであり、中でも、その真密度が1.70g/cm3以上である黒鉛又はそれに近い性質を有する高結晶性炭素材料が好ましい。
負極活物質(F)X線回折における格子面(002面)のd値が0.340nmを超える炭素材料としては、非晶質炭素が挙げられ、これは、2000℃以上の高温で熱処理してもほとんど積層秩序が変化しない炭素材料である。例えば難黒鉛化炭素(ハードカーボン)、1500℃以下で焼成したメソカーボンマイクロビーズ(MCMB)、メソペーズビッチカーボンファイバー(MCF)等が例示される。株式会社クレハ製のカーボトロン(登録商標)P等は、その代表的な事例である。
負極活物質(G)Si、Sn、Alから選ばれる1種以上の金属の酸化物としては、リチウムイオンのド-プ・脱ド-プが可能な、例えば酸化シリコン、酸化スズ等が挙げられる。
負極活物質(H)Si、Sn、Alから選ばれる1種以上の金属若しくはこれら金属を含む合金又はこれら金属若しくは合金とリチウムとの合金としては、例えばシリコン、スズ、アルミニウム等の金属、シリコン合金、スズ合金、アルミニウム合金等が挙げられ、これらの金属や合金が、充放電に伴いリチウムと合金化した材料も使用できる。
負極活物質(I)リチウムチタン酸化物としては、例えば、スピネル構造を有するチタン酸リチウム、ラムスデライト構造を有するチタン酸リチウム等を挙げることができる。
(ウ)負極は、負極集電体を有する。負極集電体としては、例えば、銅、ステンレス鋼、ニッケル、チタン又はこれらの合金等を用いることができる。
(ウ)負極は、例えば負極集電体の少なくとも一方の面に負極活物質層が形成される。負極活物質層は、例えば、前述の負極活物質と、結着剤と、必要に応じて導電剤とにより構成される。
電極は、例えば、活物質と、結着剤と、必要に応じて導電剤とを所定の配合量でN-メチル-2-ピロリドン(NMP)や水等の溶媒中に分散混練し、得られたペーストを集電体に塗布、乾燥して活物質層を形成することで得ることができる。得られた電極は、ロールプレス等の方法により圧縮して、適当な密度の電極に調節することが好ましい。
本発明の非水系電解液電池は、(エ)セパレータを備える。(イ)正極と(ウ)負極の接触を防ぐためのセパレータとしては、ポリプロピレン、ポリエチレン等のポリオレフィンや、セルロース、紙、又はガラス繊維等で作られた不織布や多孔質シートが使用される。これらのフィルムは、電解液がしみ込んでイオンが透過し易いように、微多孔化されているものが好ましい。
非水系電解液電池を構成するにあたり、非水系電解液電池の外装体としては、例えばコイン型、円筒型、角型等の金属缶や、ラミネート外装体を用いることができる。金属缶材料としては、例えばニッケルメッキを施した鉄鋼板、ステンレス鋼板、ニッケルメッキを施したステンレス鋼板、アルミニウム又はその合金、ニッケル、チタン等が挙げられる。
ラミネート外装体としては、例えば、アルミニウムラミネートフィルム、SUS製ラミネートフィルム、シリカをコーティングしたポリプロピレン、ポリエチレン等のラミネートフィルム等を用いることができる。
いずれも原料や、生成物の取り扱いは露点が-50℃以下の窒素雰囲気下にて行った。また、使用する硝子製反応器は150℃で12時間以上乾燥させた後に、露点が-50℃以下の窒素気流下で室温まで冷却させたものを用いた。
特許文献17に開示された方法に従って、シュウ酸の三配位であるトリスオキサラトリン酸リチウムを得た。トリスオキサラトリン酸リチウム(30g、99.4mmol)をジメチルカーボネート(以下DMC)(120mL)に溶解させ、フッ化水素(以下HF)(11.9g、596.4mmol)を添加した。25℃にて48時間攪拌させた後、減圧にて残留するHFとDMCの除去を行った。そしてDMC(60mL)を加えて濃縮残渣を可能な限り溶解させた後に、Li塩濃度が約45質量%となるまで濃縮を行った。シュウ酸を始めとする不溶解成分をろ過にて除去した後、(1a-Cis)と(1a-Trans)とが含まれた混合物のDMC溶液49gを得た。
混合物のDMC溶液に対してジクロロメタン(以下、「CH2Cl2」という。)を室温にて添加して12時間攪拌する事で固体が析出した。ろ過にて固体と母液に分離し、母液は減圧にて固形物が得られるまでDMCを留去した。ろ別した固体と、母液から得た固形物を別々にDMCに溶解させ、濃度約45質量%のDMC溶液を別々に調製した後にCH2Cl2を加えて固体を析出させた。ろ過にてそれぞれ固体を回収し、更に同様の手順にて数回の濃度約45質量%DMC溶液調製と固体析出を繰り返すことで、F、P純度99.9モル%(NMRより)の(1a-Cis)と(1a-Trans)が得られた。
特許文献19に記載された方法を参考に反応を実施した。20.0g(132mモル)のLiPF6とジメチルカーボネート(DMC)110mL、そしてシュウ酸11.9g(132mモル)を容積500mLの硝子製フラスコに加えた。このとき、LiPF6は完全に溶解したが、シュウ酸の大部分は溶け残っていた。25℃撹拌下、13.4g(79mモル)のSiCl4をフラスコ内へ滴下した後、撹拌を4時間継続した。続いて、減圧にてテトラフルオロシラン及び塩酸を除去し、イオン性錯体(5a-Tetra)を主成分とする粗体(純度91モル%)のDMC溶液を得た。
この溶液を、Li塩濃度が約50質量%となるまで濃縮し、濃縮液51gを得た。濾過にて不溶解成分を除去した後にCH2Cl2を攪拌しながら室温にて添加した。12時間攪拌後、ろ過にて析出した固体を回収した。再度、DMCへ溶解させてLi塩濃度約50質量%のDMC溶液を調整した後、同様の手順にてCH2Cl2添加と、固体の析出、固体の回収を行うことでF、P純度99.9%である(5a-Tetra)を得た。
原料のシュウ酸をヘキサフルオロ-2-ヒドロキシイソ酪酸に変更した以外は合成例1と同様の手法にて、(1b-Cis)、(1b-Trans)をそれぞれ得た。
ダウケミカル製強酸性陽イオン交換樹脂252(以後、イオン交換樹脂)を500g量り取り、0.1規定の水酸化ナトリウム水溶液(2.5kg)に浸漬させ、25℃で6時間攪拌を行った。ろ過でイオン交換樹脂を回収し、洗液のpHが8以下になるまで純水で充分に洗浄した。その後、12時間の減圧乾燥(120℃、1.3kPa)にて水分を除去した。
濃度10質量%の(1a-Cis)/EMC溶液を調製し、そこに液重量の半分の重量の乾燥済み前記イオン交換樹脂を加え、25℃にて6時間攪拌を行った。その後、ろ過にてイオン交換樹脂を取り除く事で、カチオンがLi+からNa+へ交換された(6a-Cis)/EMC溶液(濃度約10質量%)が得られた。イオンクロマトグラフィーにてカチオンの定量を行うと、Na+/Li+の比率は99.5であった。
また、上述の方法にて(1a-Cis)/EMC溶液の代わりに同濃度の(1a-Trans)/EMC溶液を用いる事で同様に濃度約10質量%の(6a-Trans)/EMC溶液が得られた。
合成例4で使用される(1a-cis)/EMC溶液の代わりに(5a-Tetra)/EMC溶液を用いる事で、カチオンがLi+からNa+へ交換された濃度約10質量%の(5b-Tetra)/EMC溶液が得られた。イオンクロマトグラフィーにてカチオンの定量を行うと、Na+/Li+の比率は99.4であった。
合成例4で使用される0.1規定の水酸化ナトリウム水溶液(2.5kg)を0.1規定の水酸化カリウム水溶液(2.5kg)に変更する事で、カチオンがLi+からK+へ交換された濃度約10質量%の(6b-Cis)/EMC、(6b-Trans)/EMC溶液が得られた。イオンクロマトグラフィーにてカチオンの定量を行うと、どちらの溶液もK+/Li+の比率は99.6であった。
EMC 90gにトリメチルプロピルアンモニウムクロリド 5.7g(41.7mmol)と(1a-Cis) 10.0g(39.7mmol)を加え、45℃にて6時間攪拌を行った。5℃まで冷却した後に不溶解物をろ過で取り除く事でカチオンがLi+からトリメチルプロピルアンモニウムカチオン(以下、TMPA)へ交換された(6c-Cis)/EMC溶液(濃度約13質量%)が得られた。
また、上述の方法にて(1a-Cis)の代わりに同重量の(1a-Trans)を用いる事で同様に濃度約13質量%の(6c-Trans)/EMC溶液が得られた。イオンクロマトグラフィーにてカチオンの定量を行うと、どちらの溶液もTMPA/Li+の比率は98.5であった。
EMC 90gに1-ブチル-1-メチルピロリジニウムクロリド 7.4g(41.7mmol)と(1a-Cis) 10.0g(39.7mmol)を加え、45℃にて6時間攪拌を行った。5℃まで冷却した後に不溶解物をろ過で取り除く事でカチオンがLi+から1-ブチル-1-メチルピロリジニウムカチオン(以下、PP13)へ交換された(6d-Cis)/EMC溶液(濃度約15質量%)が得られた。
また、上述の方法にて(1a-Cis)の代わりに同重量の(1a-Trans)を用いる事で同様に濃度約15質量%の(6d-Trans)/EMC溶液が得られた。イオンクロマトグラフィーにてカチオンの定量を行うと、どちらの溶液もPP13/Li+の比率は98.3であった。
非特許文献1に記載の方法を応用して前記(1-Cis)のアニオン部分が(Cis-c)でA=Liである(1c-Cis)、前記(1-Trans)のアニオン部分が(Trans-c)でA=Liである(1c-Trans)をそれぞれ得た。
露点が-50℃以下の窒素雰囲気ドライボックス中に、予め加熱、溶解させたエチレンカーボネート(EC)とエチルメチルカーボネート(EMC)の非水溶媒(体積比1:2)に、電解質としてLiPF6を濃度が1mol/Lになるように溶解、調製した後、本発明に係る種々のイオン性錯体/EMC溶液や前述(II)群の化合物とを加えることで、以下に示す本発明の非水系電解液No.1-1~1-41を調製した。
本発明に係るイオン性錯体として合成例1の(1a-Cis)を下記表1に記載した所定量添加し、さらにビニレンカーボネート(VC)を下記表1に記載した所定量添加することで、非水系電解液No.1-1~1-11を調製した。
本発明に係るイオン性錯体として合成例1の(1a-Cis)を下記表1に記載した所定量添加し、前述(II)群の化合物としてVCを下記表1に記載した所定量添加し、さらに前述(III)群の化合物として合成例1の(1a-Trans)、及び/又は前述(IV)群の化合物として合成例2の(5a-Tetra)を下記表1に記載した所定量添加することで、非水系電解液No.1-12~1-24を調製した。
本発明に係るイオン性錯体として合成例1の(1a-Cis)や合成例3の(1b-Cis)を下記表1に記載した所定量添加し、前述(II)群の化合物としてVCやビニルエチレンカーボネート(VEC)、前述(III)群の化合物として合成例1の(1a-Trans)や合成例3の(1b-Trans)、さらに前述(IV)群の化合物として合成例2の(5a-Tetra)や合成例5の(5b-Tetra)を下記表1に記載した所定量添加することで、非水系電解液No.1-25~1-31を調製した。
本発明に係るイオン性錯体として合成例1、合成例4、合成例6~合成例9のそれぞれのCis体を所定量添加し、前述(II)群の化合物としてVC、前述(III)群の化合物として合成例1、合成例4、合成例6~合成例9のそれぞれのTrans体、さらに前述(IV)群の化合物として合成例2の(5a-Tetra)を下記表1に記載した所定量添加することで、非水系電解液No.1-32~1-41を調製した。
露点が-50℃以下の窒素雰囲気ドライボックス中に、予め加熱、溶解させたECとEMCの非水溶媒(体積比1:2)に、電解質としてLiPF6を濃度が1mol/Lになるように溶解、調製することで、比較電解液No.1-1を得た。なお、下記表1に記載の種々のイオン性錯体/EMC溶液や上述(II)群の化合物を加えないほかは、本発明の非水系電解液1-1~1-41と同じ手順にて調製した。
露点が-50℃以下の窒素雰囲気ドライボックス中に、予め加熱、溶解させたECとEMCの非水溶媒(体積比1:2)に、電解質としてLiPF6を濃度が1mol/Lになるように溶解、調製した後、合成例1の(1a-Cis)を下記表1に記載した所定量添加することで、比較電解液No.1-2を調製した。
比較電解液No.1-2と同様に、合成例1の(1a-Cis)と合成例3の(1b-Cis)とを下記表1に記載した所定量添加することで、比較電解液No.1-3を調製した。
比較電解液No.1-2と同様に、表1に記載した通り、比較電解液No.1-2で添加した(1a-Cis)の代わりに、VCを1.0質量%添加することで、比較電解液No.1-4を調製した。
比較電解液No.1-4と同様に、VCを1.0質量%添加し、さらに合成例1の(1a-Trans)を下記表1に記載した所定量添加することで、比較電解液No.1-5を調製した。
比較電解液No.1-4と同様に、VCを1.0質量%添加し、さらに合成例1の(1a-Trans)、合成例2の(5a-Tetra)を下記表1に記載した所定量添加することで、比較電解液No.1-6を調製した。
圧力計を備え付けた20Lのステンレス製耐圧容器に非水系電解液21kgをそれぞれ充填し、45℃の環境温度にて2ヶ月間保管した。その後、25℃環境温度下にて容器内の内圧を計測して保管中に発生したガス量の算出を行った。
非水系電解液No.1-1~1-41及び比較電解液No.1-2~1-6のガス発生量については、比較電解液No.1-1のガス発生量を100としたときの相対値として表1に示す。
また、このガス発生抑制効果は、テトラフルオロイオン性錯体(5a-Tetra)のジフルオロイオン性錯体(1a-Cis)に対する割合、すなわち、テトラフルオロイオン性錯体(1-Tetra)/ジフルオロイオン性錯体(1-Cis)(質量比)が0.07から、0.12、0.20へと大きくなるのに伴って、そのガス発生抑制効果が高まることが確認された(例えば「電解液No.1-15~1-17」参照)。
正極活物質として、LiNi1/3Mn1/3Co1/3O2(NMC)粉末及びアセチレンブラック(導電剤)を乾式混合し、結着剤であるポリフッ化ビニリデン(PVDF)を予め溶解させたN-メチル-2-ピロリドン(NMP)中に均一に分散させ、混合し、さらに粘度調整用NMPを加え、NMC合剤ペーストを調製した。このペーストをアルミニウム箔(集電体)上に塗布して、乾燥、加圧を行った後に、所定のサイズに加工した試験用NMC正極を得た。正極中の固形分比率は、NMC:導電剤:PVDF=85:5:10(質量比)とした。
負極活物質として、黒鉛粉末を、結着剤であるPVDFを予め溶解させたNMP中に均一に分散させ、混合し、さらに粘度調整用NMPを加え、黒鉛合剤ペーストを調製した。このペーストを銅箔(集電体)上に塗布して、乾燥、加圧を行った後に、所定のサイズに加工した試験用黒鉛負極を得た。負極中の固形分比率は、黒鉛粉末:PVDF=90:10(質量比)とした。
上記の試験用NMC正極と、試験用黒鉛負極と、セルロース製セパレータとを備えるアルミラミネート外装セル(容量30mAh)に、表1に記載の非水系電解液No.1-1~1-41及び比較電解液No.1-1~1-6をそれぞれ含浸させ、実施例1-1~1-41及び比較例1-1~1-6に係る非水系電解液電池を得た。
<評価1> 60℃500サイクル後の低温特性(0℃)
実施例1-1~1-41、及び比較例1-1~1-6に係る非水系電解液電池のそれぞれについて、以下の評価を実施した。
まず、作製したセルを用いて、25℃の環境温度で、以下の条件でコンディショニングを実施した。すなわち、初回充放電として、充電上限電圧4.3V、0.1Cレート(3mA)で定電流定電圧充電し、放電終止電圧3.0Vまで0.2Cレート(6mA)定電流で放電を行い、その後、充電上限電圧4.3V、0.2Cレート(6mA)で定電流定電圧充電し、放電終止電圧3.0Vまで0.2Cレート(6mA)定電流で放電を行う充放電サイクルを3回繰り返した。
このコンディショニング後、60℃の環境温度での充放電試験を実施した。充電は、充電上限電圧4.3Vまで3Cレート(90mA)で定電流定電圧充電を実施し、放電は、放電終止電圧3.0Vまで3Cレート(90mA)定電流で放電を行う充放電サイクルを500回繰り返した。
続いて25℃まで非水系電解液電池を冷却し、再度3.0Vまで放電させた後に、0℃、0.2Cレートにて4.3Vまで定電流定電圧充電を実施した。更に0℃のまま、放電は、放電終止電圧3.0Vまで5Cレート(150mA)での定電流で放電を行い、この時に得られる容量を、60℃長期サイクル後の低温特性(0℃)とした。
上述評価1にて60℃の環境温度で500サイクルを実施後、続いて25℃まで非水系電解液電池を冷却し、再度3.0Vまで放電させた後に、25℃、5Cレートにて4.3Vまで定電流定電圧充電を実施した。更に25℃のまま、放電は、放電終止電圧3.0Vまで5Cレート(150mA)での定電流で放電を行い、この時に得られる容量を、60℃長期サイクル後の5Cレート特性(25℃)とした。
実施例1-1~1-41、及び比較例1-1~1-6に係る非水系電解液電池のそれぞれについて、60℃の環境温度での貯蔵試験(4.3V充電後、10日間保存)を実施した。
続いて25℃まで非水系電解液電池を冷却し、3.0Vまで放電させた後に、0℃、0.2Cレートにて4.3Vまで定電流定電圧充電を実施した。更に0℃のまま、放電は、放電終止電圧3.0Vまで5Cレート(150mA)での定電流で放電を行い、この時に得られる容量を、60℃貯蔵後の低温特性(0℃)とした。
表1、表2の結果から、実施例に係る合成例1のシス配座のジフルオロイオン性錯体(1a-Cis)とVCとを含む非水系電解液電池は、該イオン性錯体とVCの両方を含まない非水系電解液電池(比較例1-1)と比較して高い60℃長期サイクル後放電容量(0℃)、60℃長期サイクル後の5Cレート特性が得られた。
実施例1-4と比較例1-2とを比較すると、同(1a-Cis)とVCとを含む非水系電解液電池の方が、同(1a-Cis)のみを含む非水系電解液電池よりも効果が高い事が確認された。
従って、表2に示されるように、60℃長期サイクル後の放電容量(0℃)や5Cレート特性(25℃)などで格段の特性改善が確認されたものと思われ、このジフルオロイオン性錯体(1a-Cis)とVCなどの不飽和結合を有するカーボネートとを組み合わせるという新規な構成により、他に類を見ない特性改善効果が得られたものと思われる。
合成例1のシス配座のジフルオロイオン性錯体(1a-Cis)とトランス配座のジフルオロイオン性錯体(1a-Trans)、そしてVCの3種類の化合物を含む非水系電解液を用いた実施例1-12~1-14の場合は、同(1a-Cis)とVCとを含む非水系電解液電池(実施例1-4)に比べて、60℃長期サイクル後放電容量(0℃)を低下させる事なく、さらに60℃貯蔵後放電容量(0℃)を向上させる傾向があることが確認された。
また、実施例1-16と比較例1-6とを比較すると、同(1a-Cis)とVC、(IV)群の化合物として(5a-Tetra)の3種類の化合物を含む非水系電解液電池の方が、トランス配座のジフルオロイオン性錯体(1a-Trans)とVC、(IV)群の化合物として(5a-Tetra)とを含む非水系電解液電池よりも効果が高い事が確認された。
さらにシス配座のジフルオロイオン性錯体(1a-Cis)に対するトランス配座のジフルオロイオン性錯体(1a-Trans)の割合、すなわち、ジフルオロイオン性錯体(1-Trans)/ジフルオロイオン性錯体(1-Cis)(質量比)が0.002から0.005、0.01へと大きくなるに従って、60℃長期サイクル後放電容量(0℃)に悪影響を与えることなく60℃貯蔵後放電容量(0℃)が幾分向上する傾向が確認できた。
さらに、ジフルオロイオン性錯体(1a-Cis)、VC、そしてテトラフルオロイオン性錯体(5a-Tetra)の3種類の化合物を含む非水系電解液を用いた実施例1-15~1-17の場合は、同(1a-Cis)とVCとを含む非水系電解液電池(実施例1-4)に比べて、60℃長期サイクル後放電容量(0℃)や5Cレート特性(25℃)を低下させる事なく、さらに60℃貯蔵後放電容量(0℃)を向上させる傾向があることが確認された。
また、シス配座のジフルオロイオン性錯体(1a-Cis)に対するテトラフルオロイオン性錯体(5a-Tetra)の割合、すなわち、テトラフルオロイオン性錯体(5a-Tetra)/ジフルオロイオン性錯体(1-Cis)(質量比)が0.07から、0.12、0.20へと大きくなるのに伴って、60℃長期サイクル後放電容量(0℃)に悪影響を与えることなく60℃貯蔵後放電容量(0℃)が向上する傾向が確認できた。
また、実施例1-18~実施例1-31に示されるように、合成例1のシス配座のジフルオロイオン性錯体(1a-Cis)や合成例3のシス配座のジフルオロイオン性錯体(1b-Cis)、VCやVEC、合成例1のトランス配座のジフルオロイオン性錯体(1a-Trans)や合成例3のトランス配座のジフルオロイオン性錯体(1b-Trans)、合成例2に示されるテトラフルオロイオン性錯体(5a-Tetra)や合成例5のテトラフルオロイオン性錯体(5b-Tetra)の4つの群から選ばれる化合物を含む非水系電解液については、テトラフルオロイオン性錯体(5a-Tetra)や(5b-Tetra)を含まない非水系電解液(実施例1-12~1-14)や、トランス配座のジフルオロイオン性錯体(1a-Trans)や(1b-Trans)を含まない非水系電解液(実施例1-15~1-17)よりも60℃長期サイクル後放電容量(0℃)や5Cレート特性(25℃)や60℃貯蔵後放電容量(0℃)が向上する傾向があることが確認された(例えば、上記(I)群の化合物と上記(II)群の化合物の含有量がそれぞれの実施例において同程度である、「実施例1-12~1-17」と「実施例1-21、1-25~1-31」との比較)。
一方、実施例1-32~実施例1-35に示されるように、Li+、Na+、K+をカチオンとして有するイオン性錯体(1a-Cis)、(6a-Cis)、(6b-Cis)を比較すると、その効果に差はなく、いずれも高いサイクル後放電容量(0℃)を得られた(実施例1-21又は1-30と、実施例1-32、1-33との比較)。シス配座体がトランス配座体よりも高い効果を示す傾向も同じであった(実施例1-32~1-36と、実施例1-37~1-41において(I)群と(III)群の対応する組み合わせとの比較)。同様に、Li+、TMPA、PP13をカチオンとして有するイオン性錯体(1a-Cis)、(6c-Cis)、(6d-Cis)を比較すると、TMPA、PP13の場合でも効果はあるものの、Li+が一番優れている結果となった(実施例1-21又は1-30と、実施例1-34、1-35との比較)。これは、TMPA、PP13はカチオンの分子量が大きいため、有効部位であるアニオン側の含有量が減少した事と、TMPA、PP13の一部が還元又は酸化分解され、その分解残渣が高抵抗成分として電極表面上に堆積したためだと推測される。
本発明の非水系電解液No.2-1~2-31については、前述の非水系電解液No.1-1~1-41と同様の手順にて調製した。
すなわち、非水溶媒としてEC、EMC(体積比1:2)、電解質としてLiPF6を濃度が1mol/Lになるように溶解、調製した後で、本発明に係る種々のイオン性錯体/EMC溶液や 上述(II)群の化合物とを加えることで、以下に示す非水系電解液No.2-1~2-31をそれぞれ調製した。
本発明に係るイオン性錯体として合成例1の(1a-Cis)を後述の表3に記載した所定量添加し、さらにVECを表3に記載した所定量添加することで、非水系電解液No.2-1~2-11を調製した。
本発明に係るイオン性錯体として合成例1の(1a-Cis)を後述の表3に記載した所定量添加し、前述(II)群の化合物としてVECを下記表3に記載した所定量添加し、さらに前述(III)群の化合物として合成例1の(1a-Trans)、及び/又は前述(IV)群の化合物として合成例2の(5a-Tetra)を表3に記載した所定量添加することで、非水系電解液 No.2-12~2-24を調製した。
本発明に係るイオン性錯体として合成例1の(1a-Cis)や合成例3の(1b-Cis)を後述する表3に記載した所定量添加し、前述(II)群の化合物として VECやエチニルエチレンカーボネート(EEC)、前述(III)群の化合物として合成例1の(1a-Trans)や合成例3の(1b-Trans)、さらに前述(IV)群の化合物として合成例2の(5a-Tetra)や合成例5の(5b-Tetra)を表3に記載した所定量添加することで、非水系電解液No.2-25~2-31を調製した。
比較電解液No.1-4と同様の手順、組成にて、後述の表3に記載した通り、VCの代わりにVECを1.0質量%添加することで、比較電解液No.2-1を調製した。
比較電解液No.1-5と同様の手順、組成にて、後述の表3に記載した通り、VCの代わりにVECを1.0質量%添加し、さらに合成例1の(1a-Trans)を後述の表3に記載した所定量添加することで、比較電解液No.2-2を調製した。
比較電解液No.1-6と同様の手順、組成にて、後述の表3に記載した通り、VCの代わりにVECを1.0質量%添加し、さらに合成例1の(1a-Trans)を後述の表3に記載した所定量添加することで、比較電解液No.2-3を調製した。
圧力計を備え付けた20Lのステンレス製耐圧容器に非水系電解液21kgをそれぞれ充填し、45℃の環境温度にて2ヶ月間保管した。その後、25℃環境温度下にて容器内の内圧を計測して保管中に発生したガス量の算出を行った。
非水系電解液No.2-1~2-31及び比較電解液No.1-2、1-3、No.2-1、2-2、2-3のガス発生量については、比較電解液No.1-1のガス発生量を100としたときの相対値として表3に示す。
また、このガス発生抑制効果は、テトラフルオロイオン性錯体(5a-Tetra)のジフルオロイオン性錯体(1a-Cis)に対する割合、すなわち、テトラフルオロイオン性錯体(1-Tetra)/ジフルオロイオン性錯体(1-Cis)(質量比)が0.07から、0.12、0.20へと大きくなるのに伴って、そのガス発生抑制効果が高まることが確認された(例えば「電解液No.2-15~2-17」)。
前述の実施例1-1~1-41、及び比較例1-1~1-6に係る非水系電解液電池と同様の手順にて、試験用NMC正極と、試験用黒鉛負極と、セルロース製セパレータとを備えるアルミラミネート外装セル(容量30mAh)に、表3に記載の非水系電解液No.2-1~2-31、比較電解液No.2-1、2-2をそれぞれ含浸させ、実施例2-1~実施例2-31及び比較例2-1~比較例2-3に係る非水系電解液電池を作製した。これら非水系電解液電池については、前述の実施例1-1~1-41、及び比較例1-1~1-6と同様、それぞれ前述の以下の評価を実施した。
<評価1> 60℃500サイクル後の低温特性(0℃)
<評価2> 60℃500サイクル後の5Cレート特性
<評価3> 60℃貯蔵後の低温特性(0℃)
表3~表4の結果から、実施例に係る合成例1のシス配座のジフルオロイオン性錯体(1a-Cis)と、VECとを含む非水系電解液電池は、該イオン性錯体と、VECの両方を含まない非水系電解液電池(比較例1-1)と比較して高い60℃長期サイクル後放電容量(0℃)、60℃長期サイクル後の5Cレート特性が得られた。
実施例2-4と比較例1-2とを比較すると、同(1a-Cis)とVECとを含む非水系電解液電池の方が、同(1a-Cis)のみを含む非水系電解液電池よりも効果が高い事が確認された。
これは、前述の実施例1-1~実施例1-11や実施例1-16等と同様に、本発明の非水系電解液のジフルオロイオン性錯体(1a-Cis)とVECなどの不飽和結合を有するカーボネートを含有することで、これら添加剤が1サイクル目充電時に同(1a-Cis)、VEC(もしくはEEC)の順に負極上で還元分解することにより、負極表面に安定な被膜(SEI)を形成するためと思われる。
合成例1のシス配座のジフルオロイオン性錯体(1a-Cis)とトランス配座のジフルオロイオン性錯体(1a-Trans)、そしてVECの3種類の化合物を含む非水系電解液を用いた実施例2-12~2-14の場合は、同(1a-Cis)とVECとを含む非水系電解液電池(実施例2-4)に比べて、60℃長期サイクル後放電容量(0℃)を低下させる事なく、さらに60℃貯蔵後放電容量(0℃)を向上させる傾向があることが確認された。
また、シス配座のジフルオロイオン性錯体(1a-Cis)に対するトランス配座のジフルオロイオン性錯体(1a-Trans)の割合、すなわち、ジフルオロイオン性錯体(1-Trans)/ジフルオロイオン性錯体(1-Cis)(質量比)が0.002から0.005、0.01へと大きくなるに従って、60℃長期サイクル後放電容量(0℃)に悪影響を与えることなく60℃貯蔵後放電容量(0℃)が幾分向上する傾向が確認できた。
さらに、シス配座のジフルオロイオン性錯体(1a-Cis)、VEC、そしてテトラフルオロイオン性錯体(5a-Tetra)の3種類の化合物を含む非水系電解液を用いた実施例2-15~2-17の場合は、同ジフルオロイオン性錯体(1a-Cis)とVECとを含む非水系電解液電池(実施例2-4)に比べて、60℃長期サイクル後放電容量(0℃)や5Cレート特性(25℃)を低下させる事なく、さらに60℃貯蔵後放電容量(0℃)を向上させる傾向があることが確認された。
また、上記のいずれにおいても、シス配座のジフルオロイオン性錯体(1a-Cis)に対するテトラフルオロイオン性錯体(5a-Tetra)の割合、すなわち、テトラフルオロイオン性錯体(5a-Tetra)/ジフルオロイオン性錯体(1-Cis)(質量比)が0.07から、0.12、0.20へと大きくなるのに伴って、60℃長期サイクル後放電容量(0℃)に悪影響を与えることなく60℃貯蔵後放電容量(0℃)が向上する傾向が確認できた。
また、実施例2-18~実施例2-31に示されるように、合成例1のシス配座のジフルオロイオン性錯体(1a-Cis)や合成例3のシス配座のジフルオロイオン性錯体(1b-Cis)、VECやEEC、合成例1のトランス配座のジフルオロイオン性錯体(1a-Trans)や合成例3のトランス配座のジフルオロイオン性錯体(1b-Trans)、合成例2に示されるテトラフルオロイオン性錯体(5a-Tetra)や合成例5のテトラフルオロイオン性錯体(5b-Tetra)の4つの群から選ばれる化合物を含む非水系電解液については、テトラフルオロイオン性錯体(5a-Tetra)や(5b-Tetra)を含まない非水系電解液(実施例2-12~2-14)や、トランス配座のジフルオロイオン性錯体(1a-Trans)や(1b-Trans)を含まない非水系電解液(実施例2-15~2-17)よりも60℃長期サイクル後放電容量(0℃)や5Cレート特性(25℃)や60℃貯蔵後放電容量(0℃)が向上する傾向があることが確認された(例えば、上記(I)群の化合物と上記(II)群の化合物の含有量がそれぞれの実施例において同程度である、「実施例2-12~2-17」と「実施例2-21、2-25~2-31」との比較)。
本発明の非水系電解液No.3-1~3-28についても、前述の非水系電解液No.1-1~1-41と同様の手順にて調製した。
すなわち、非水溶媒としてEC、EMC(体積比1:2)、電解質としてLiPF6を濃度が1mol/Lになるように溶解、調製した後で、本発明に係る種々のイオン性錯体/EMC溶液や前述(II)群の化合物とを加えることで、以下に示す非水系電解液No.3-1~3-28を調製した。
本発明に係るイオン性錯体として合成例1の(1a-Cis)や合成例3の(1b-Cis)を後述の表5に記載した所定量添加し、前述(II)群の化合物としてフルオロエチレンカーボネート(FEC)やVC、前述(III)群の化合物として合成例1の(1a-Trans)や合成例3の(1b-Trans)、さらに前述(IV)群の化合物として合成例2の(5a-Tetra)や合成例5の(5b-Tetra)を表5に記載した所定量添加することで、非水系電解液No.3-1~3-28を調製した。
比較電解液No.1-4と同様の手順、組成にて、後述の表5に記載した通り、VCの代わりにFECを2.0質量%添加することで、比較電解液No.3-1を調製した。
比較電解液No.1-5と同様の手順、組成にて、後述の表5に記載した通り、VCの代わりにFECを2.0質量%添加し、さらに合成例1の(1a-Trans)を後述の表5に記載した所定量添加することで、比較電解液No.3-2を調製した。
比較電解液No.1-6と同様の手順、組成にて、後述の表5に記載した通り、VCの代わりにFECを2.0質量%添加し、さらに合成例1の(1a-Trans)、合成例2の(5a-Tetra)を後述の表5に記載した所定量添加することで、比較電解液No.3-3を調製した。
前述の実施例1-1~1-41、及び比較例1-1~1-6に係る非水系電解液電池と同様の手順にて、試験用NMC正極と、試験用黒鉛負極と、セルロース製セパレータとを備えるアルミラミネート外装セル(容量30mAh)に、後述の表6に記載の非水系電解液No.3-1~3-28、比較電解液No.3-1、3-2をそれぞれ含浸させ、実施例3-1~実施例3-28及び比較例3-1、比較例3-2、比較例3-3に係る非水系電解液電池を作製した。これら非水系電解液電池については、前述の実施例1-1~1-41、及び比較例1-1~1-6と同様、それぞれ前述の以下の評価を実施した。
<評価1> 60℃500サイクル後の低温特性(0℃)
<評価2> 60℃500サイクル後の5Cレート特性
<評価3> 60℃貯蔵後の低温特性(0℃)
表6の結果から、実施例に係る合成例1のシス配座のジフルオロイオン性錯体(1a-Cis)と、FEC又はtrans-DFECとを含む非水系電解液電池は、同イオン性錯体と、FEC又はtrans-DFECの双方を含まない非水系電解液電池(比較例1-1)と比較して高い60℃長期サイクル後放電容量(0℃)、60℃長期サイクル後の5Cレート特性が得られた。
実施例3-4と比較例1-2とを比較すると、同(1a-Cis)とFECとを含む非水系電解液電池の方が、同(1a-Cis)のみを含む非水系電解液電池よりも効果が高い事が確認された。
これは、本発明の非水系電解液のジフルオロイオン性錯体(1a-Cis)とFECなどのフッ素原子を含有するカーボネートを含有することで、これら添加剤が1サイクル目充電時にジフルオロイオン性錯体(1a-Cis)、FEC(もしくはtrans-DFEC)の順に負極上で還元分解することにより、負極表面に安定な被膜(SEI)を形成するためと思われる。
ジフルオロイオン性錯体(1a-Cis)と(1a-Trans)、そしてFECの3種類の化合物を含む非水系電解液を用いた実施例3-12~4-14の場合は、同(1a-Cis)とFECとを含む非水系電解液電池(実施例3-4)に比べて、60℃長期サイクル後放電容量(0℃)を低下させる事なく、さらに60℃貯蔵後放電容量(0℃)を向上させる傾向があることが確認された。
また、シス配座のジフルオロイオン性錯体(1a-Cis)に対するトランス配座のジフルオロイオン性錯体(1a-Trans)の割合、すなわち、ジフルオロイオン性錯体(1-Trans)/ジフルオロイオン性錯体(1-Cis)(質量比)が0.002から0.005、0.01へと大きくなるに従って、60℃長期サイクル後放電容量(0℃)に悪影響を与えることなく60℃貯蔵後放電容量(0℃)が幾分向上する傾向が確認できた。
さらに、ジフルオロイオン性錯体(1a-Cis)、FEC、そしてテトラフルオロイオン性錯体(5a-Tetra)の3種類の化合物を含む非水系電解液を用いた実施例3-15~3-17の場合は、同(1a-Cis)とFECとを含む非水系電解液電池(実施例3-4)に比べて、60℃長期サイクル後放電容量(0℃)や5Cレート特性(25℃)を低下させる事なく、さらに60℃貯蔵後放電容量(0℃)を向上させる傾向があることが確認された。
また、シス配座のジフルオロイオン性錯体(1a-Cis)に対するテトラフルオロイオン性錯体(5a-Tetra)の割合、すなわち、テトラフルオロイオン性錯体(5a-Tetra)/ジフルオロイオン性錯体(1-Cis)(質量比)が0.07から、0.12、0.20へと大きくなるのに伴って、60℃長期サイクル後放電容量(0℃)に悪影響を与えることなく60℃貯蔵後放電容量(0℃)が向上する傾向が確認できた。
実施例3-18~実施例3-28に示されるように、合成例1のシス配座のジフルオロイオン性錯体(1a-Cis)や合成例3のシス配座のジフルオロイオン性錯体(1b-Cis)、FECやVC、合成例1のトランス配座のジフルオロイオン性錯体(1a-Trans)や合成例3のトランス配座のジフルオロイオン性錯体(1b-Trans)、合成例2に示されるテトラフルオロイオン性錯体(5a-Tetra)や合成例5のテトラフルオロイオン性錯体(5b-Tetra)の4つの群から選ばれる化合物を含む非水系電解液については、テトラフルオロイオン性錯体(5a-Tetra)や(5b-Tetra)を含まない非水系電解液(実施例3-12~3-14)や、トランス配座のジフルオロイオン性錯体(1a-Trans)や(1b-Trans)を含まない非水系電解液(実施例3-15~3-17)よりも60℃長期サイクル後放電容量(0℃)や5Cレート特性(25℃)や60℃貯蔵後放電容量(0℃)が向上する傾向があることが確認された(例えば、上記(I)群の化合物と上記(II)群の化合物の含有量がそれぞれの実施例において同程度である、「実施例3-12~3-17」と「実施例3-21、3-25~3-28」との比較)。
本発明の非水系電解液No.4-1~4-20についても、非水系電解液No.1-1~1-41と同様の手順にて調製した。
すなわち、非水溶媒としてEC、EMC(体積比1:2)、電解質としてLiPF6を濃度が1mol/Lになるように溶解、調製した後で、本発明に係る種々のイオン性錯体/EMC溶液や前述(II)群の化合物とを加えることで、以下に示す非水系電解液No.4-1~4-20を調製した。
本発明に係るイオン性錯体として合成例1の(1a-Cis)や合成例3の(1b-Cis)を後述の表7に記載した所定量添加し、前述(II)群の化合物として、1,6-ジイソシアナトヘキサン(1,6-DICNH)やVC、前述(III)群の化合物として、合成例1の(1a-Trans)や合成例3の(1b-Trans)、さらに前述(IV)群の化合物として、合成例2の(5a-Tetra)や合成例5の(5b-Tetra)を表7に記載した所定量添加することで、非水系電解液No.4-1~4-20を調製した。
比較電解液No.1-4と同様の手順、組成にて、後述の表7に記載した通り、VCの代わりに1,6-DICNHを0.5質量%添加することで、比較電解液No.4-1を調製した。
比較電解液No.1-6と同様の手順、組成にて、後述の表7に記載した通り、VCの代わりに1,6-DICNHを0.5質量%添加し、さらに合成例1の(1a-Trans)、合成例2の(5a-Tetra)を後述の表7に記載した所定量添加することで、比較電解液No.4-2を調製した。
前述の実施例1-1~1-41、及び比較例1-1~1-6に係る非水系電解液電池と同様の手順にて、試験用NMC正極と、試験用黒鉛負極と、セルロース製セパレータとを備えるアルミラミネート外装セル(容量30mAh)に、後述の表8に記載の非水系電解液No.4-1~4-20、比較電解液No.4-1、4-2をそれぞれ含浸させ、実施例4-1~実施例4-20及び比較例4-1、比較例4-2に係る非水系電解液電池を作製した。これら非水系電解液電池については、前述の実施例1-1~1-41、及び比較例1-1~1-6と同様、それぞれ前述の以下の評価を実施した。
<評価1> 60℃500サイクル後の低温特性(0℃)
<評価2> 60℃500サイクル後の5Cレート特性
<評価3> 60℃貯蔵後の低温特性(0℃)
表8の結果から、実施例4-1~実施例4-20については、実施例3-1~実施例3-28と同様、(I)群の化合物として合成例1の(1a-Cis)や合成例3の(1b-Cis)と、(II)群の化合物として1,6-DICNHやVCとを併用し、さらに、(III)群の化合物として合成例1の(1a-Trans)や合成例3の(1b-Trans)、そして(IV)群の化合物として合成例2に示されるテトラフルオロイオン性錯体(5a-Tetra)や合成例5の(5b-Tetra)から選ばれる化合物を含みうる非水系電解液を用いることで、比較例4-1、比較例4-2よりも60℃長期サイクル後放電容量(0℃)や5Cレート特性(25℃)や60℃貯蔵後放電容量(0℃)のいずれも向上することが確認された。
前述の実施例1-1~1-41、及び比較例1-1~1-6に係る非水系電解液電池にて用いた正極活物質(LiNi1/3Mn1/3Co1/3O2(NMC))の代わりに、リチウム・ニッケル・コバルト・アルミニウム複合酸化物LiNi0.85Co0.10Al0.05O2(NCA)粉末を用いて、以下の手順にて試験用NCA正極を作製した。
LiNi0.85Co0.10Al0.05O2(NCA)粉末(戸田工業製)及びアセチレンブラック(導電剤)を乾式混合し、結着剤であるPVDFを予め溶解させたNMP中に均一に分散させ、混合し、さらに粘度調整用NMPを加え、NCA合剤ペーストを調製した。このペーストをアルミニウム箔(集電体)上に塗布して、乾燥、加圧を行った後に、所定のサイズに加工した試験用NCA正極を得た。正極中の固形分比率は、NCA:導電剤:PVDF=85:5:10(質量比)とした。
上記の試験用NCA正極と、試験用黒鉛負極と、セルロース製セパレータとを備えるアルミラミネート外装セル(容量30mAh)に、表9に記載の種々の非水系電解液及び種々の比較電解液をそれぞれ含浸させ、実施例5-1~5-16及び比較例5-1~5-10に係る非水系電解液電池を得た。なお、表9は既出の電解液の組成をまとめたものである。
<評価1> 60℃500サイクル後の低温特性(0℃)
実施例5-1~5-16、及び比較例5-1~5-10に係る非水系電解液電池のそれぞれについて、実施例1-1~1-41、及び比較例1-1~1-6に係る非水系電解液電池での評価1にて、25℃の環境温度でのコンディショニングの初回充放電にて、充電上限電圧4.3Vを4.2Vに変更し、0.1Cレート(3mA)で定電流定電圧充電し、放電終止電圧3.0Vまで0.2Cレート(6mA)定電流で放電を行い、その後、充電上限電圧4.3Vを4.2Vに変更し、0.2Cレート(6mA)で定電流定電圧充電し、放電終止電圧3.0Vまで0.2Cレート(6mA)定電流で放電を行う充放電サイクルを3回繰り返した。
さらに、このコンディショニング後、60℃の環境温度で500サイクルを実施する際にて、充電上限電圧4.3Vを4.2Vに変更したこと、0℃、0.2Cレートにて4.3Vまで定電流定電圧充電することを4.2Vまで定電流定電圧充電に変更したこと以外は、同様の評価とした。この時に得られる容量を、60℃長期サイクル後の低温特性(0℃)とした。
実施例5-1~5-16、比較例5-1~5-10に係る非水系電解液電池のそれぞれについては、実施例1-1~1-41、及び比較例1-1~1-6に係る非水系電解液電池での評価2である、25℃、5Cレートにて4.3Vまで定電流定電圧充電することを、4.2Vまで定電流定電圧充電に変更したこと以外は、同様の評価とした。この時に得られる容量を、60℃長期サイクル後の5Cレート特性(25℃)とした。
実施例5-1~5-16、比較例5-1~5-10に係る非水系電解液電池のそれぞれについては、実施例1-1~1-41、及び比較例1-1~1-6に係る非水系電解液電池での評価3である60℃の環境温度での貯蔵試験(4.3V定電流定電圧充電後を4.2V定電流定電圧充電後に変更して10日間保存)を実施したこと、そして、0℃、0.2Cレートにて4.3Vまで定電流定電圧充電することを、4.2Vまで定電流定電圧充電に変更したこと以外は、同様の評価とした。この時に得られる容量を、60℃貯蔵後の低温特性(0℃)とした。
表10の結果から、正極活物質としてNMCの代わりに、NCAを用いた場合においても、実施例に係る(I)群の化合物として、合成例1のシス配座のジフルオロイオン性錯体(1a-Cis)と(II)群の化合物としてVC、VEC、FEC、1,6-DICNHとをそれぞれ含む非水系電解液電池は、該イオン性錯体とVCの両方を含まない非水系電解液電池(比較例5-1)と比較して、高い60℃長期サイクル後放電容量(0℃)、60℃長期サイクル後の5Cレート特性が得られた。
また、実施例5-1、実施例5-5、実施例5-9、実施例5-13と、比較例5-2とを比較すると、同(1a-Cis)と(II)群の化合物とをそれぞれ含む非水系電解液電池の方が、同(1a-Cis)のみを含む非水系電解液電池よりも効果が高い事が確認された。
これは、実施例5-7((II)群の化合物;VEC)と比較例5-6、実施例5-11((II)群の化合物;FEC)と比較例5-8、実施例5-15((II)群の化合物;1,6-DICNH)と比較例5-10でも同様に効果があることが確認された。
実施例6-1~6-16、及び比較例6-1~6-10に係る非水系電解液電池については、前述の実施例5-1~5-16、及び比較例5-1~5-10に係る非水系電解液電池にて用いた正極活物質(LiNi0.85Co0.10Al0.05O2(NCA))の代わりに、リチウム含有オリビン型リン酸塩としてLiFePO4(LFP)粉末を用いて、以下の手順にて試験用LFP正極を作製した。
LiFePO4(LFP)粉末及びアセチレンブラック(導電剤1)と、気相法炭素繊維(昭和電工製VGCF(登録商標)-H)(導電剤2)とを乾式混合し、結着剤であるPVDFを予め溶解させたNMP中に均一に分散させ、混合し、さらに粘度調整用NMPを加え、LFP合剤ペーストを調製した。このペーストをアルミニウム箔(集電体)上に塗布して、乾燥、加圧を行った後に、所定のサイズに加工した試験用LFP正極を得た。
正極中の固形分比率は、LFP:導電剤1:導電剤2:PVDF=85:4:1:10(質量比)とした。
上記の試験用LFP正極と、試験用黒鉛負極と、微多孔性ポリプロピレン-ポリエチレン2層フィルムからなるセパレータとを備えるアルミラミネート外装セル(容量30mAh)に、表9に記載の種々の非水系電解液及び種々の比較電解液をそれぞれ含浸させ、前述の実施例5-1~5-16、及び比較例5-1~5-10と同様の手順にて、実施例6-1~6-16、及び比較例6-1~6-10に係る非水系電解液電池を得た。
<評価1> 60℃500サイクル後の低温特性(0℃)
実施例6-1~6-16、及び比較例6-1~6-10に係る非水系電解液電池のそれぞれについて、以下の評価を実施した。
まず、前述の通り作製したセルを用いて、25℃の環境温度で、以下の条件でコンディショニングを実施した。すなわち、初回充放電として、充電上限電圧3.6V、0.1Cレート(3mA)で定電流定電圧充電し、放電終止電圧2.0Vまで0.2Cレート(6mA)定電流で放電を行い、その後、充電上限電圧3.6V、0.2Cレート(6mA)で定電流定電圧充電し、放電終止電圧2.0Vまで0.2Cレート(6mA)定電流で放電を行う充放電サイクルを3回繰り返した。
このコンディショニング後、60℃の環境温度での充放電試験を実施した。充電は、充電上限電圧3.6Vまで3Cレート(90mA)で定電流定電圧充電を実施し、放電は、放電終止電圧2.0Vまで3Cレート(90mA)定電流で放電を行う充放電サイクルを500回繰り返した。
続いて25℃まで非水系電解液電池を冷却し、再度2.0Vまで放電させた後に、0℃、0.2Cレートにて3.6Vまで定電流定電圧充電を実施した。更に0℃のまま、放電は、放電終止電圧2.0Vまで5Cレート(150mA)での定電流で放電を行い、この時に得られる容量を、60℃長期サイクル後の低温特性(0℃)とした。
上述評価1にて60℃の環境温度で500サイクルを実施後、続いて25℃まで非水系電解液電池を冷却し、再度2.0Vまで放電させた後に、25℃、5Cレートにて3.6Vまで定電流定電圧充電を実施した。更に25℃のまま、放電は、放電終止電圧2.0Vまで5Cレート(150mA)での定電流で放電を行い、この時に得られる容量を、60℃長期サイクル後の5Cレート特性(25℃)とした。
実施例6-1~6-16、及び比較例6-1~6-10に係る非水系電解液電池のそれぞれについて、60℃の環境温度での貯蔵試験(3.6V充電後、10日間保存)を実施した。
続いて25℃まで非水系電解液電池を冷却し、2.0Vまで放電させた後に、0℃、0.2Cレートにて3.6Vまで定電流定電圧充電を実施した。更に0℃のまま、放電は、放電終止電圧2.0Vまで5Cレート(150mA)での定電流で放電を行い、この時に得られる容量を、60℃貯蔵後の低温特性(0℃)とした。
表11の結果から、実施例6-1~6-16については、実施例5-1~実施例5-16と同様の傾向を示した。
すなわち、正極活物質としてNCAの代わりに、LFPを用いた場合においても、実施例に係る(I)群の化合物として、合成例1の(1a-Cis)と、(II)群の化合物としてVC、VEC、FEC、1,6-DICNHとを併用し、(III)群の化合物として合成例1の(1a-Trans)、そして(IV)群の化合物として合成例2に示されるテトラフルオロイオン性錯体(5a-Tetra)から選ばれる化合物を含みうる非水系電解液を用いることで、比較例6-1~比較例6-10よりも60℃長期サイクル後放電容量(0℃)や5Cレート特性(25℃)や60℃貯蔵後放電容量(0℃)のいずれも向上することが確認された。
[非水系電解液No.7-1~7-5、比較電解液No.7-2~7-8の調製]
露点が-50℃以下の窒素雰囲気ドライボックス中に、予め加熱、溶解させたECとEMCの非水溶媒と前述(II)群の化合物であるFEC(体積比25:70:5 / 質量比29.7:63.6:6.7)に、電解質としてLiPF6を濃度が1.2mol/Lになるように溶解、調製した後、本発明に係る種々のイオン性錯体/EMC溶液や、前述(II)群の化合物とを加えることで、本発明の非水系電解液No.7-1~7-5、比較電解液No.7-2~7-8を調製した。
すなわち、前述(I)群の化合物である合成例1の(1a-Cis)、前述(II)群の化合物2としてVC、VEC、EEC、2-アリルコハク酸無水物、1,6-DICNH、(III)群の化合物として合成例1の(1a-Trans)、そして、(IV)群の化合物として合成例2のテトラフルオロイオン性錯体(5a-Tetra)の4つの群から選ばれる化合物をそれぞれ下記表12に記載した所定量添加することで、非水系電解液No.7-1~7-5、比較電解液No.7-2~7-8を調製した。
露点が-50℃以下の窒素雰囲気ドライボックス中に、予め加熱、溶解させたECとEMCの非水溶媒と前述(II)群の化合物であるFEC(体積比20:70:10/質量比23.6:63.1:13.3)に、電解質としてLiPF6を濃度が1.2mol/Lになるように溶解、調製した後、本発明に係る種々のイオン性錯体/EMC溶液や前述(II)群の化合物とを加えることで、本発明の非水系電解液No.7-6~7-10、比較電解液No.7-9~7-15を調製した。
すなわち、前述(I)群の化合物である合成例1の(1a-Cis)、前述(II)群の化合物2としてVC、VEC、EEC、2-アリルコハク酸無水物、1,6-DICNH、(III)群の化合物として合成例1の(1a-Trans)、そして、(IV)群の化合物として合成例2のテトラフルオロイオン性錯体(5a-Tetra)の4つの群から選ばれる化合物をそれぞれ下記表12に記載した所定量添加することで、非水系電解液No.7-6~7-10、比較電解液No.7-9~7-15を調製した。
露点が-50℃以下の窒素雰囲気ドライボックス中に、予め加熱、溶解させたECとEMCの非水溶媒(体積比30:70 / 質量比35.9:64.1)に、電解質としてLiPF6を濃度が1.2mol/Lになるように溶解、調製することで、比較電解液No.7-1を得た。なお、下記表12に記載の種々のイオン性錯体/EMC溶液や上述(II)群の化合物を加えないほかは、本発明の非水系電解液7-1~7-5と同じ手順にて比較電解液No.7-1を調製した。
前述の実施例5-1~5-16、及び比較例5-1~5-10に係る非水系電解液電池にて用いた正極活物質(LiNi0.85Co0.10Al0.05O2(NCA))の代わりに、層状岩塩型構造を有するリチウム過剰層状遷移金属酸化物として0.5[LiNi0.5Mn0.5O2]・0.5[Li2MnO3](OLO-1)粉末を用いて、以下の手順にて試験用OLO-1正極を作製した。
0.5[LiNi0.5Mn0.5O2]・0.5[Li2MnO3](OLO-1)粉末及びアセチレンブラック(導電剤1)、気相法炭素繊維(昭和電工製VGCF(登録商標)-H)(導電剤2)とを乾式混合し、結着剤であるPVDFを予め溶解させたNMP中に均一に分散させ、混合し、さらに粘度調整用NMPを加え、OLO-1合剤ペーストを調製した。このペーストをアルミニウム箔(集電体)上に塗布して、乾燥、加圧を行った後に、所定のサイズに加工した試験用OLO-1正極を得た。正極中の固形分比率は、OLO-1:導電剤1:導電剤2:PVDF=85:4:1:10(質量比)とした。
上記の試験用OLO-1正極と、試験用黒鉛負極と、微多孔性ポリプロピレン-ポリエチレン2層フィルムからなるセパレータとを備えるアルミラミネート外装セル(容量30mAh)に、表12に記載の種々の非水系電解液、及び種々の比較電解液をそれぞれ含浸させ、前述の実施例5-1~5-16、及び比較例5-1~5-10と同様の手順にて、実施例7-1~7-10、及び比較例7-1~7-15に係る非水系電解液電池を得た。
<評価1> 60℃300サイクル後の低温特性(0℃)
実施例7-1~7-10、及び比較例7-1~7-15に係る非水系電解液電池のそれぞれについて、以下の評価を実施した。
まず、25℃の環境温度で、以下の条件でコンディショニングを実施した。
すなわち、作製したセルを用いて、25℃の環境温度で、初回充放電として、充電上限電圧4.2V、0.05Cレート(1.5mA)で定電流定電圧充電し、放電終止電圧2.5Vまで0.1Cレート(3mA)定電流で放電を実施した。その後、充電上限電圧4.4V、0.1Cレート(3mA)で定電流定電圧充電し、放電終止電圧2.5Vまで0.1Cレート(3mA)定電流で放電を行う充放電サイクルを5回繰り返した。
このコンディショニング後、25℃の環境温度で、充電上限電圧4.6V、0.1Cレート(3mA)で定電流定電圧充電し、放電終止電圧2.5Vまで0.2Cレート(6mA)定電流で放電を行う充放電サイクルを3回繰り返した。
その後、60℃の環境温度での充放電試験を実施した。充電は、充電上限電圧4.6Vまで1Cレート(30mA)で定電流定電圧充電を実施し、放電は、放電終止電圧2.5Vまで2Cレート(60mA)定電流で放電を行う充放電サイクルを300回繰り返した。
続いて25℃まで非水系電解液電池を冷却し、再度2.5Vまで放電させた後に、0℃、0.2Cレートにて4.6Vまで定電流定電圧充電を実施した。更に0℃のまま、放電終止電圧2.5Vまで3Cレート(90mA)での定電流で放電を行い、この時に得られる容量を、60℃長期サイクル後の低温特性(0℃)とした。
上述評価1にて60℃の環境温度で300サイクルを実施後、続いて25℃まで非水系電解液電池を冷却し、再度2.5Vまで放電させた後に、25℃、0.1Cレートにて4.6Vまで定電流定電圧充電を実施した。更に25℃のまま、放電は、放電終止電圧2.5Vまで3Cレート(90mA)での定電流で放電を行い、この時に得られる容量を、60℃長期サイクル後の3Cレート特性(25℃)とした。
実施例7-1~7-10、及び比較例7-1~7-15に係る非水系電解液電池のそれぞれについて、60℃の環境温度での貯蔵試験(4.6V充電後、10日間保存)を実施した。
続いて25℃まで非水系電解液電池を冷却し、2.5Vまで放電させた後に、0℃、0.2Cレートにて4.6Vまで定電流定電圧充電を実施した。更に0℃のまま、放電は、放電終止電圧2.5Vまで3Cレート(90mA)での定電流で放電を行い、この時に得られる容量を、60℃貯蔵後の低温特性(0℃)とした。
表13の結果から、実施例7-1~実施例7-10については、正極活物質としてOLO-1を用いた場合においても、実施例に係る(I)群の化合物として合成例1の(1a-Cis)、(II)群の化合物としてVC、VEC、EEC、FEC、2-アリルコハク酸無水物、1,6-DICNH、(III)群の化合物として合成例1の(1a-Trans)、そして(IV)群の化合物として合成例2に示されるテトラフルオロイオン性錯体(5a-Tetra)の4つの群から選ばれる化合物をそれぞれ含む非水系電解液を用いることで、比較例7-1~比較例7-15よりも60℃長期サイクル後放電容量(0℃)や3Cレート特性(25℃)や60℃貯蔵後放電容量(0℃)のいずれも向上することが確認された。
つまり、本発明の非水系電解液及びこれを用いた電池には、特定の正極に依存せず、ある程度電池が使用された状態においても低温にて高い出力特性を発揮でき、さらに高温にて貯蔵された後においても同様に低温にて十分な性能を発揮できることは明らかである。
前述の実施例1-1~1-41、及び比較例1-1~1-6に係る非水系電解液電池にて用いた負極活物質(黒鉛粉末)の代わりに、X線回折における格子面(002面)のd値が0.340nmを超える炭素材料として、非晶質炭素粉末を用いて、以下の手順にて試験用非晶質炭素負極を作製した。
非晶質炭素粉末としては、株式会社クレハ製のカーボトロン(登録商標)Pを用い、結着剤であるPVDFを予め溶解させたNMP中に均一に分散させ、混合し、さらに粘度調整用NMPを加え、非晶質炭素合剤ペーストを調製した。このペーストを銅箔(集電体)上に塗布して、乾燥、加圧を行った後に、所定のサイズに加工した試験用非晶質炭素負極を得た。負極中の固形分比率は、非晶質炭素粉末:PVDF=90:10(質量比)とした。
[非水系電解液No.8-1~8-24、比較電解液No.8-2~8-14の調製]
露点が-50℃以下の窒素雰囲気ドライボックス中に、プロピレンカーボネート(PC)とEMC、DECの非水溶媒(体積比30:40:30 / 質量比34.1:38.3:27.6)に、電解質としてLiPF6を濃度が1.1mol/Lになるように溶解、調製した後、本発明に係る種々のイオン性錯体/EMC溶液や前述(II)群の化合物とを加えることで、本発明の非水系電解液No.8-1~8-24、及び比較電解液No.8-2~8-14を調製した。
すなわち、前述(I)群の化合物である合成例1の(1a-Cis)、前述(II)群の化合物としてVC、VEC、EEC、FEC、2-アリルコハク酸無水物、1,6-DICNH、(III)群の化合物として合成例1の(1a-Trans)、そして、(IV)群の化合物として合成例2のテトラフルオロイオン性錯体(5a-Tetra)の4つの群から選ばれる化合物をそれぞれ下記表14に記載した所定量添加することで、非水系電解液No.8-1~8-24、及び比較電解液No.8-2~8-14を調製した。
露点が-50℃以下の窒素雰囲気ドライボックス中に、PCとEMC、DECの非水溶媒(体積比30:40:30 / 質量比34.1:38.3:27.6)に、電解質としてLiPF6を濃度が1.1mol/Lになるように溶解、調製することで、比較電解液No.8-1を得た。
なお、下記表14に記載の種々のイオン性錯体/EMC溶液や上述(II)群の化合物を加えないほかは、本発明の非水系電解液8-1~8-24と同じ手順にて比較電解液No.8-1を調製した。
上記の試験用NMC正極と、試験用非晶質炭素負極と、微多孔性ポリプロピレン-ポリエチレン2層フィルムからなるセパレータとを備えるアルミラミネート外装セル(容量30mAh)に、表14に記載の種々の非水系電解液及び種々の比較電解液をそれぞれ含浸させ、実施例8-1~8-24及び比較例8-1~8-14に係る非水系電解液電池を得た。
<評価1> 60℃500サイクル後の低温特性(0℃)
実施例8-1~8-24、及び比較例8-1~8-14に係る非水系電解液電池のそれぞれについては、実施例5-1~5-24、及び比較例5-1~5-14に係る非水系電解液電池での評価1にて、25℃の環境温度で、以下の条件でコンディショニングを実施した。
すなわち、作製したセルを用いて、25℃の環境温度で、初回充放電として、充電上限電圧4.2V 0.1Cレート(3mA)で定電流定電圧充電し、放電終止電圧2.7Vまで0.2Cレート(6mA)定電流で放電を行い、その後、充電上限電圧4.2V、0.2Cレート(6mA)で定電流定電圧充電し、放電終止電圧2.7Vまで0.2Cレート(6mA)定電流で放電を行う充放電サイクルを3回繰り返した。
このコンディショニング後、60℃の環境温度で500サイクルを実施する際にて、放電終止電圧3.0Vを2.7Vに変更したこと、0℃、0.2Cレートにて4.2Vまで定電流定電圧充電し、更に0℃のまま放電の際、放電終止電圧3.0Vを2.7Vに変更し、5Cレート(150mA)での定電流で放電に変更したこと以外は、同様の評価とした。この時に得られる容量を、60℃長期サイクル後の低温特性(0℃)とした。
実施例8-1~8-24、比較例8-1~8-14に係る非水系電解液電池のそれぞれについては、実施例5-1~5-24、比較例5-1~5-14に係る非水系電解液電池での評価2である、25℃5Cレートでの放電の際、放電終止電圧3.0Vを2.7Vに変更したこと以外は、同様の評価とした。この時に得られる容量を、60℃長期サイクル後の5Cレート特性(25℃)とした。
実施例8-1~8-24、比較例8-1~8-14に係る非水系電解液電池のそれぞれについては、実施例5-1~5-24、比較例5-1~5-14に係る非水系電解液電池での評価3である60℃の環境温度での貯蔵試験(4.2V定電流定電圧充電後、10日間保存)を実施し、0℃のまま、5Cレートでの放電の際、放電終止電圧3.0Vを2.7Vに変更したこと以外は、同様の評価とした。この時に得られる容量を、60℃貯蔵後の低温特性(0℃)とした。
表15の結果から、実施例8-1~実施例8-24については、負極活物質として黒鉛粉末の代わりに、非晶質炭素粉末(カーボトロン(登録商標)P)を用いた場合においても、実施例に係る(I)群の化合物として合成例1の(1a-Cis)と、(II)群の化合物としてVC、VEC、EEC、FEC、2-アリルコハク酸無水物、1,6-DICNHとを併用し、(III)群の化合物として合成例1の(1a-Trans)、そして、(IV)群の化合物として合成例2に示されるテトラフルオロイオン性錯体(5a-Tetra)から選ばれる化合物を含みうる非水系電解液を用いることで、比較例8-1~比較例8-14よりも60℃長期サイクル後放電容量(0℃)や5Cレート特性(25℃)や60℃貯蔵後放電容量(0℃)のいずれも向上することが確認された。
[非水系電解液No.9-1~9-24、比較電解液No.9-2~9-14の調製]
露点が-50℃以下の窒素雰囲気ドライボックス中に、予め加熱、溶解させたECとEMC、DECの非水溶媒(体積比25:45:30/質量比30.7:42.2:27.1)に、電解質としてLiPF6を濃度が1.2mol/Lになるように溶解、調製した後、本発明に係る種々のイオン性錯体/EMC溶液や前述(II)群の化合物とを加えることで、本発明の非水系電解液No.9-1~9-24、及び比較電解液No.9-2~9-14を調製した。
すなわち、前述(I)群の化合物である合成例1の(1a-Cis)、前述(II)群の化合物としてVC、VEC、EEC、FEC、2-アリルコハク酸無水物、1,6-DICNH、(III)群の化合物として合成例1の(1a-Trans)、そして、(IV)群の化合物として合成例2のテトラフルオロイオン性錯体(5a-Tetra)の4つの群から選ばれる化合物をそれぞれ下記表16に記載した所定量添加することで、非水系電解液No.9-1~9-24、及び比較電解液No.9-2~9-14を調製した。
露点が-50℃以下の窒素雰囲気ドライボックス中に、予め加熱、溶解させたECとEMC、DECの非水溶媒(体積比25:45:30 / 質量比30.7:42.2:27.1)に、電解質としてLiPF6を濃度が1.2mol/Lになるように溶解、調製することで、比較電解液No.9-1を得た。
なお、下記表16に記載の種々のイオン性錯体/EMC溶液や上述(II)群の化合物を加えないほかは、本発明の非水系電解液9-1~9-24と同じ手順にて比較電解液No.9-1を調製した。
前述の実施例8-1~8-24、及び比較例8-1~8-14に係る非水系電解液電池にて用いた負極活物質(非晶質炭素粉末)の代わりに、人造黒鉛負極と天然黒鉛とを混合した負極活物質を用いて、以下の手順にて試験用(人造黒鉛+天然黒鉛混合)負極を作製した。
人造黒鉛としては、昭和電工(株)製SCMG(登録商標)-AR粉末、天然黒鉛として関西熱化学(株)製天然黒鉛粒子(平均粒子径25μm)を用い、結着剤であるPVDFを予め溶解させたNMP中に均一に分散させ、混合し、さらに粘度調整用NMPを加え、(人造黒鉛+天然黒鉛)混合の合剤ペーストを調製した。このペーストを銅箔(集電体)上に塗布して、乾燥、加圧を行った後に、所定のサイズに加工した試験用(人造黒鉛+天然黒鉛混合)負極を得た。負極中の固形分比率は、人造黒鉛粉末:天然黒鉛粉末:PVDF=72:18:10(質量比)とした。
上記の試験用NMC正極と、試験用(人造黒鉛+天然黒鉛混合)負極と、微多孔性ポリプロピレン-ポリエチレン2層フィルムからなるセパレータとを備えるアルミラミネート外装セル(容量30mAh)に、表16に記載の種々の非水系電解液、及び種々の比較電解液をそれぞれ含浸させ、前述の実施例6-1~6-16、及び比較例6-1~6-10と同様の手順にて、実施例9-1~9-24、及び比較例9-1~9-14に係る非水系電解液電池を得た。
これら非水系電解液電池については、前述の実施例1-1~1-41、及び比較例1-1~1-6と同様、それぞれ前述の以下の評価を実施した。
<評価1> 60℃500サイクル後の低温特性(0℃)
<評価2> 60℃500サイクル後の5Cレート特性
<評価3> 60℃貯蔵後の低温特性(0℃)
表17の結果から、実施例9-1~実施例9-24については、実施例8-1~実施例8-24と同様の傾向を示した。
すなわち、負極活物質として人造黒鉛と天然黒鉛とを混合した粉末を用いた場合においても、実施例に係る(I)群の化合物として合成例1の(1a-Cis)と、(II)群の化合物としてVC、VEC、EEC、FEC、2-アリルコハク酸無水物、1,6-DICNHとを併用し、さらに、(III)群の化合物として合成例1の(1a-Trans)、そして(IV)群の化合物として合成例2に示されるテトラフルオロイオン性錯体(5a-Tetra)から選ばれる化合物を含みうる非水系電解液を用いることで、比較例9-1~比較例9-14よりも60℃長期サイクル後放電容量(0℃)や5Cレート特性(25℃)や60℃貯蔵後放電容量(0℃)のいずれも向上することが確認された。
[非水系電解液No.10-1~10-5、比較電解液No.10-2~10-8の調製]
露点が-50℃以下の窒素雰囲気ドライボックス中に、予め加熱、溶解させたECとEMCの非水溶媒と前述(II)群の化合物であるFEC(体積比20:70:10 /質量比23.6:63.1:13.3)に、電解質としてLiPF6を濃度が1.2mol/Lになるように溶解、調製した後、本発明に係る種々のイオン性錯体/EMC溶液や前述(II)群の化合物とを加えることで、本発明の非水系電解液No.10-1~10-5、及び比較電解液No.10-2~10-8を調製した。
すなわち、前述(I)群の化合物である合成例1の(1a-Cis)、前述(II)群の化合物2としてVC、VEC、EEC、2-アリルコハク酸無水物、1,6-DICNH、(III)群の化合物として合成例1の(1a-Trans)、そして、(IV)群の化合物として合成例2のテトラフルオロイオン性錯体(5a-Tetra)の4つの群から選ばれる化合物をそれぞれ下記表18に記載した所定量添加することで、非水系電解液No.10-1~10-5、及び比較電解液No.10-2~10-8を調製した。
露点が-50℃以下の窒素雰囲気ドライボックス中に、予め加熱、溶解させたECとEMCの非水溶媒と前述(II)群の化合物であるFEC(体積比15:70:15 /質量比17.5:62.6:19.9)に、電解質としてLiPF6を濃度が1.2mol/Lになるように溶解、調製した後、本発明に係る種々のイオン性錯体/EMC溶液や前述(II)群の化合物とを加えることで、本発明の非水系電解液No.10-6~10-10、及び比較電解液No.10-9~10-15を調製した。
すなわち、前述(I)群の化合物である合成例1の(1a-Cis)、前述(II)群の化合物2としてVC、VEC、EEC、2-アリルコハク酸無水物、1,6-DICNH、(III)群の化合物として合成例1の(1a-Trans)、そして、(IV)群の化合物として合成例2のテトラフルオロイオン性錯体(5a-Tetra)の4つの群から選ばれる化合物をそれぞれ下記表18に記載した所定量添加することで、非水系電解液No.10-6~10-10、及び比較電解液No.10-9~10-15を調製した。
露点が-50℃以下の窒素雰囲気ドライボックス中に、予め加熱、溶解させたECとEMCの非水溶媒(体積比30:70 / 質量比35.9:64.1)に、電解質としてLiPF6を濃度が1.2mol/Lになるように溶解、調製することで、比較電解液No.10-1を得た。なお、下記表18に記載の種々のイオン性錯体/EMC溶液や上述(II)群の化合物を加えないほかは、本発明の非水系電解液10-1~10-5と同じ手順にて比較電解液No.10-1を調製した。
前述の実施例9-1~9-24、及び比較例9-1~9-14に係る非水系電解液電池にて用いた負極活物質(人造黒鉛と天然黒鉛とを混合した粉末)の代わりに、ケイ素酸化物粉末と塊状人造黒鉛粉末の混合粉末を負極活物質として用いて、以下の手順にて試験用SiOx負極を作製した。
ケイ素酸化物粉末としては、熱処理により不均化されたケイ素酸化物粉末(シグマアルドリッチジャパン株式会社製SiOx(xは0.3~1.6)、平均粒径5μm)、塊状人造黒鉛粉末として日立化成工業製MAG-D(粒径20μm以下)の混合粉末を用い、結着剤であるPVDFを予め溶解させたNMP中に均一に分散させ、さらにケッチェンブラック(導電剤)を加えて混合し、さらに粘度調整用NMPを加え、SiOx合剤ペーストを調製した。
このペーストを銅箔(集電体)上に塗布して、乾燥、加圧を行った後に、所定のサイズに加工した試験用SiOx負極を得た。負極中の固形分比率は、SiOx:MAG―D:導電剤:PVDF=35:47:8:10(質量比)とした。
なお、SiOx負極の充電容量がNMC正極の充電容量よりも大きくなるように、NMC正極活物質とSiOx粉末との量を調節し、充電の途中でSiOx負極にリチウム金属が析出しないように塗布量も調節した。
上記の試験用NMC正極と、試験用SiOx負極と、微多孔性ポリプロピレン-ポリエチレン2層フィルムからなるセパレータとを備えるアルミラミネート外装セル(容量30mAh)に、表18に記載の種々の非水系電解液、及び種々の比較電解液をそれぞれ含浸させ、前述の実施例9-1~9-24、及び比較例9-1~9-14と同様の手順にて、実施例10-1~10-10、及び比較例10-1~10-15に係る非水系電解液電池を得た。
なお、前述の実施例6-1~6-16、及び比較例6-1~6-10と同様、微多孔性ポリプロピレン-ポリエチレン2層フィルムからなるセパレータのポリプロピレン側を正極側に配置するように介して、正極、負極を対向させ、非水系電解液電池を得た。
<評価1> 60℃200サイクル後の低温特性(0℃)
実施例10-1~10-10、及び比較例10-1~10-15に係る非水系電解液電池のそれぞれについて、以下の評価を実施した。
まず、25℃の環境温度で、以下の条件でコンディショニングを実施した。
すなわち、作製したセルを用いて、25℃の環境温度で、初回充放電として、充電上限電圧4.2V、0.05Cレート(1.5mA)で定電流定電圧充電し、放電終止電圧2.5Vまで0.1Cレート(3mA)定電流で放電を行い、その後、充電上限電圧4.2V、0.1Cレート(3mA)で定電流定電圧充電し、放電終止電圧2.5Vまで0.1Cレート(3mA)定電流で放電を行う充放電サイクルを5回繰り返した。
このコンディショニング後、25℃の環境温度で、充電上限電圧4.2V、0.2Cレート(6mA)で定電流定電圧充電し、放電終止電圧2.5Vまで0.2Cレート(6mA)定電流で放電を行う充放電サイクルを3回繰り返した。
その後、60℃の環境温度での充放電試験を実施した。充電は、充電上限電圧4.2Vまで1Cレート(30mA)で定電流定電圧充電を実施し、放電は、放電終止電圧2.5Vまで2Cレート(60mA)定電流で放電を行う充放電サイクルを200回繰り返した。
続いて25℃まで非水系電解液電池を冷却し、再度2.5Vまで放電させた後に、0℃、0.2Cレートにて4.2Vまで定電流定電圧充電を実施した。更に0℃のまま、放電終止電圧2.5Vまで3Cレート(90mA)での定電流で放電を行い、この時に得られる容量を、60℃長期サイクル後の低温特性(0℃)とした。
上述評価1にて60℃の環境温度で200サイクルを実施後、続いて25℃まで非水系電解液電池を冷却し、再度2.5Vまで放電させた後に、25℃、0.1Cレートにて4.2Vまで定電流定電圧充電を実施した。更に25℃のまま、放電は、放電終止電圧2.5Vまで3Cレート(90mA)での定電流で放電を行い、この時に得られる容量を、60℃長期サイクル後の3Cレート特性(25℃)とした。
実施例10-1~10-10、及び比較例10-1~10-15に係る非水系電解液電池のそれぞれについて、60℃の環境温度での貯蔵試験(4.2V充電後、10日間保存)を実施した。
続いて25℃まで非水系電解液電池を冷却し、2.5Vまで放電させた後に、0℃、0.2Cレートにて4.2Vまで定電流定電圧充電を実施した。更に0℃のまま、放電は、放電終止電圧2.5Vまで3Cレート(90mA)での定電流で放電を行い、この時に得られる容量を、60℃貯蔵後の低温特性(0℃)とした。
負極活物質として人造黒鉛と天然黒鉛とを混合した粉末の代わりに、ケイ素酸化物粉末と塊状人造黒鉛粉末の混合粉末を用いた実施例10-1~実施例10-10については、表19の結果から、以下のことが確認された。
すなわち、実施例に係る(I)群の化合物として合成例1の(1a-Cis)、(II)群の化合物としてVC、VEC、EEC、FEC、2-アリルコハク酸無水物、1,6-DICNH、(III)群の化合物として合成例1の(1a-Trans)、そして、(IV)群の化合物として合成例2に示されるテトラフルオロイオン性錯体(5a-Tetra)の4つの群から選ばれる化合物をそれぞれ含む非水系電解液を用いることで、比較例10-1~比較例10-15よりも60℃長期サイクル後放電容量(0℃)や3Cレート特性(25℃)や60℃貯蔵後放電容量(0℃)のいずれも向上することが確認された。
前述の実施例10-1~10-10、及び比較例10-1~10-15に係る非水系電解液電池にて用いた負極活物質(ケイ素酸化物粉末と塊状人造黒鉛粉末の混合粉末)の代わりに、Si粉末を負極活物質として用いて、以下の手順にて試験用Si負極を作製した。
Si粉末としては、Si粉末(平均粒子径:10μm/6μm=質量比9/1の混合粉末)を用い、結着剤であるPVDFを予め溶解させたNMP中に均一に分散させ、さらにケッチェンブラック(導電剤1)と気相法炭素繊維(昭和電工製VGCF(登録商標)-H)(導電剤2)とを加えて混合し、さらに粘度調整用NMPを加え、Si合剤ペーストを調製した。
このペーストを銅箔(集電体)上に塗布して、乾燥、加圧を行った後に、所定のサイズに加工した試験用Si負極を得た。
負極中の固形分比率は、Si粉末:導電剤1:導電剤2:PVDF=78:7:3:12(質量比)とした。
なお、Si負極の充電容量がNMC正極の充電容量よりも大きくなるように、NMC正極活物質とSi粉末との量を調節し、充電の途中でSi負極にリチウム金属が析出しないように塗布量を調節した。
上記の試験用NMC正極と、試験用Si負極と、微多孔性ポリプロピレン-ポリエチレン2層フィルムからなるセパレータとを備えるアルミラミネート外装セル(容量30mAh)に、表18に記載の種々の非水系電解液、及び種々の比較電解液をそれぞれ含浸させ、前述の実施例10-1~10-10、及び比較例10-1~10-15と同様の手順にて、実施例11-1~11-10、及び比較例11-1~11-15に係る非水系電解液電池を得た。
前述の実施例10-1~10-10、及び比較例10-1~10-15に係る非水系電解液電池と同様、それぞれ前述の以下の評価を実施した。
<評価1> 60℃200サイクル後の低温特性(0℃)
<評価2> 60℃200サイクル後の3Cレート特性
<評価3> 60℃貯蔵後の低温特性(0℃)
表20の結果から、負極活物質として、Si粉末を用いた場合においても、実施例に係る(I)群の化合物として合成例1の(1a-Cis)、(II)群の化合物としてVC、VEC、EEC、FEC、2-アリルコハク酸無水物、1,6-DICNH、(III)群の化合物として合成例1の(1a-Trans)、そして、(IV)群の化合物として合成例2に示されるテトラフルオロイオン性錯体(5a-Tetra)の4つの群から選ばれる化合物をそれぞれ含む非水系電解液を用いることで、比較例11-1~比較例11-15よりも60℃長期サイクル後放電容量(0℃)や3Cレート特性(25℃)や60℃貯蔵後放電容量(0℃)のいずれも向上することが確認された。
[非水系電解液No.12-1~12-12、比較電解液No.12-2~12-8の調製]
露点が-50℃以下の窒素雰囲気ドライボックス中に、PCとEMCの非水溶媒(体積比30:70 / 質量比33.8:66.2)に、電解質としてLiPF6と、LiBF4の濃度がそれぞれ1.1mol/L、0.4mol/Lになるように溶解、調製した後、本発明に係る種々のイオン性錯体/EMC溶液や前述(II)群の化合物とを加えることで、本発明の非水系電解液No.12-1~12-12、及び比較電解液No.12-2~12-8を調製した。
すなわち、前述の(I)群の化合物である合成例1の(1a-Cis)、前述(II)群の化合物として1,6-DICNH、1-ICNE、1,4-ジイソシアナトブタン(1,4-DICNB)、(III)群の化合物として合成例1の(1a-Trans)、そして、(IV)群の化合物として合成例2のテトラフルオロイオン性錯体(5a-Tetra)の4つの群から選ばれる化合物をそれぞれ下記表21に記載した所定量添加することで、非水系電解液No.12-1~12-12、及び比較電解液No.12-2~12-8を調製した。
露点が-50℃以下の窒素雰囲気ドライボックス中に、PCとEMCの非水溶媒(体積比30:70 / 質量比33.8:66.2)に、電解質としてLiPF6と、LiBF4の濃度がそれぞれ1.1mol/L、0.4mol/Lになるように溶解、調製することで、比較電解液No.12-1を得た。
なお、下記表21に記載の種々のイオン性錯体/EMC溶液や上述(II)群の化合物を加えないほかは、本発明の非水系電解液12-1~12-12と同じ手順にて比較電解液No.12-1を調製した。
前述の実施例11-1~11-10、及び比較例11-1~11-15に係る非水系電解液電池にて用いた負極活物質(Si粉末)の代わりに、Li4Ti5O12(LTO)粉末を負極活物質として用いて、以下の手順にて試験用LTO合金負極を作製した。
Li4Ti5O12(LTO)粉末としては、LTO粉末(平均粒子径:0.90μm/3.40μm=質量比9/1の混合粉末)を用い、結着剤であるPVDFを予め溶解させたNMP中に均一に分散させ、さらにケッチェンブラック(導電剤1)と気相法炭素繊維(昭和電工製VGCF(登録商標)-H)(導電剤2)を加えて混合し、さらに粘度調整用NMPを加え、LTO合剤ペーストを調製した。
このペーストをアルミニウム箔(集電体)上に塗布して、乾燥、加圧を行った後に、所定のサイズに加工した試験用LTO負極を得た。
負極中の固形分比率は、LTO粉末:導電剤1:導電剤2:PVDF=83:5:2:10(質量比)とした。
上記の試験用NMC正極と、試験用LTO負極と、セルロースからなるセパレータとを備えるアルミラミネート外装セル(容量30mAh)に、表21に記載の種々の非水系電解液、及び種々の比較電解液をそれぞれ含浸させ、前述の実施例6-1~6-16、及び比較例6-1~6-10と同様の手順にて、実施例12-1~12-12、及び比較例12-1~12-8に係る非水系電解液電池を得た。
<評価1> 60℃500サイクル後の低温特性(0℃)
実施例12-1~12-12、及び比較例12-1~12-8に係る非水系電解液電池のそれぞれについて、以下の評価を実施した。
まず、25℃の環境温度で、以下の条件でコンディショニングを実施した。
すなわち、作製したセルを用いて、25℃の環境温度で、初回充放電として、充電上限電圧2.8V、0.1Cレート(3mA)で定電流定電圧充電し、放電終止電圧1.5Vまで0.1Cレート(3mA)定電流で放電を行い、その後、充電上限電圧2.8V、0.1Cレート(3mA)で定電流定電圧充電し、放電終止電圧1.5Vまで0.1Cレート(3mA)定電流で放電を行う充放電サイクルを3回繰り返した。
このコンディショニング後、25℃の環境温度で、充電上限電圧2.8V、0.2Cレート(6mA)で定電流定電圧充電し、放電終止電圧1.5Vまで0.2Cレート(6mA)定電流で放電を行う充放電サイクルを3回繰り返した。
その後、60℃の環境温度での充放電試験を実施した。充電は、充電上限電圧2.8Vまで2Cレート(30mA)で定電流定電圧充電を実施し、放電終止電圧1.5Vまで2Cレート(60mA)定電流で放電を行う充放電サイクルを500回繰り返した。
続いて25℃まで非水系電解液電池を冷却し、再度1.5Vまで放電させた後に、0℃、0.2Cレートにて2.8Vまで定電流定電圧充電を実施した。更に0℃のまま、放電終止電圧1.5Vまで5Cレート(150mA)での定電流で放電を行い、この時に得られる容量を、60℃長期サイクル後の低温特性(0℃)とした。
上述評価1にて60℃の環境温度で500サイクルを実施後、続いて25℃まで非水系電解液電池を冷却し、再度1.5Vまで放電させた後に、25℃、0.1Cレートにて2.8Vまで定電流定電圧充電を実施した。更に25℃のまま、放電終止電圧1.5Vまで5Cレート(150mA)での定電流で放電を行い、この時に得られる容量を、60℃長期サイクル後の5Cレート特性(25℃)とした。
実施例12-1~12-12、及び比較例12-1~12-8に係る非水系電解液電池のそれぞれについて、60℃の環境温度での貯蔵試験(2.8V充電後、10日間保存)を実施した。
続いて25℃まで非水系電解液電池を冷却し、1.5Vまで放電させた後に、0℃、0.2Cレートにて2.8Vまで定電流定電圧充電を実施した。更に0℃のまま、放電終止電圧1.5Vまで5Cレート(150mA)での定電流で放電を行い、この時に得られる容量を60℃貯蔵後の低温特性(0℃)とした。
表22の結果から、負極活物質としてLTOを用いた場合においても、実施例に係る(I)群の化合物として合成例1の(1a-Cis)と、(II)群の化合物として1,6-DICNH、1-ICNE、1,4-DICNBとを併用し、さらに、(III)群の化合物として合成例1の(1a-Trans)、そして(IV)群の化合物として合成例2に示されるテトラフルオロイオン性錯体(5a-Tetra)から選ばれる化合物を含みうる非水系電解液を用いることで、比較例12-1~比較例12-8よりも60℃長期サイクル後放電容量(0℃)や5Cレート特性(25℃)や60℃貯蔵後放電容量(0℃)のいずれも向上することが確認された。
つまり、本発明の非水系電解液及びこれを用いた電池には、前述の正極と同様、特定の負極に依存せずにサイクル特性の改善効果が生じることは明らかである。
Claims (19)
- 非水有機溶媒と該非水有機溶媒に溶解される電解質とを含む非水系電解液において、
(I)一般式(1-Cis)で示されるシス型の立体配座をとるジフルオロイオン性錯体(1-Cis)と、
(II)不飽和結合を有するカーボネート、フッ素原子を有するカーボネート、酸無水物、及びイソシアナト基を有する化合物からなる群から選ばれる少なくとも1種の化合物と、
を含むことを特徴とする非水系電解液。
- 前記(II)群の化合物が、下記(II-1)~(II-4)からなることを特徴とする請求項1に記載の非水系電解液。
(II-1) 一般式(II-1a)及び/又は(II-1b)で示される不飽和結合を有するカーボネート。
(II-2) 一般式(II-2a)で示されるフッ素原子を有するカーボネート。
(II-3) 一般式(II-3a)で示される酸無水物。
(II-4) 一般式(II-4a)で示されるイソシアナト基を有する化合物。
但し、R7~R10のうち少なくとも一つにフッ素原子を有する。R7~R10はエーテル結合を含んでもよい。)
- 前記ジフルオロイオン性錯体(1-Cis)のアニオン部分の各元素が、以下に示される(Cis-a)、(Cis-b)、(Cis-c)及び(Cis-d)からなる群より選ばれる少なくとも一つであることを特徴とする請求項1又は2に記載の非水系電解液。
(Cis-a)M=P、X=O、Y=C、p、q、t=1、r=0
(Cis-b)M=P、X=O、W=C(CF3)2、p、q=0、r、t=1
(Cis-c)M=Si、X=O、Y=C、p、q=1、t=2、r=0
(Cis-d)M=P、X=N(R1)、Y=C、R1=CH3、p、q、t=1、r=0 - 前記ジフルオロイオン性錯体(1-Cis)の前記A+がリチウムイオン、ナトリウムイオン、カリウムイオン、及び四級アルキルアンモニウムイオンからなる群より選ばれる少なくとも1種のイオンであることを特徴とする請求項1~3のいずれかに記載の非水系電解液。
- 前記ジフルオロイオン性錯体(1-Cis)の含有量が非水系電解液に対して0.001質量%以上20質量%以下の範囲であり、
前記(II)群の化合物の合計含有量が非水系電解液に対して0.01質量%以上25質量%以下の範囲であり、
前記(II)群の化合物が非水系電解液に対してそれぞれ以下の範囲で少なくとも1種含まれていることを特徴とする、請求項1~4のいずれかに記載の非水系電解液。
(II-1)不飽和結合を有するカーボネート:0.01質量%以上5質量%以下の範囲
(II-2)フッ素原子を有するカーボネート:0.01質量%以上20質量%以下の範囲
(II-3)酸無水物:0.01質量%以上2質量%以下の範囲
(II-4)イソシアナト基を有する化合物:0.01質量%以上5質量%以下の範囲 - さらに、(III)一般式(1-Trans)で示されるトランス型の立体配座をとるジフルオロイオン性錯体(1-Trans)を含むことを特徴とする請求項1~5のいずれか1項に記載の非水系電解液。
- 前記ジフルオロイオン性錯体(1-Trans)のアニオン部分の各元素が、以下に示される(Trans-a)、(Trans-b)、(Trans-c)及び(Trans-d)からなる群より選ばれる少なくとも一つであることを特徴とする請求項6に記載の非水系電解液。
(Trans-a)M=P、X=O、Y=C、p、q、t=1、r=0
(Trans-b)M=P、X=O、W=C(CF3)2、p、q=0、r、t=1
(Trans-c)M=Si、X=O、Y=C、p、q=1、t=2、r=0
(Trans-d)M=P、X=N(R1)、Y=C、R1=CH3、p、q、t=1、r=0 - 前記ジフルオロイオン性錯体(1-Trans)の前記A+がリチウムイオン、ナトリウムイオン、カリウムイオン、及び四級アルキルアンモニウムイオンからなる群より選ばれる少なくとも1種のイオンであることを特徴とする請求項6又は7に記載の非水系電解液。
- 前記ジフルオロイオン性錯体(1-Trans)の含有量の、前記ジフルオロイオン性錯体(1-Cis)の質量に対する割合が0.0001以上、0.05以下であることを特徴とする請求項6~8のいずれかに記載の非水系電解液。
- さらに、(IV)一般式(1-Tetra)で示されるテトラフルオロイオン性錯体を含むことを特徴とする請求項1~9のいずれか1項に記載の非水系電解液。
- 前記テトラフルオロイオン性錯体のアニオン部分の各元素が、以下に示される(Tetra-a)、(Tetra-b)、(Tetra-c)及び(Tetra-d)からなる群より選ばれるいずれかであることを特徴とする請求項10に記載の非水系電解液。
(Tetra-a)M=P、X=O、Y=C、p、q、t=1、r=0
(Tetra-b)M=P、X=O、W=C(CF3)2、p、q=0、r、t=1
(Tetra-c)M=Si、X=O、Y=C、p、q=1、t=2、r=0
(Tetra-d)M=P、X=N(R1)、Y=C、R1=CH3、p、q、t=1、r=0 - 前記A+がリチウムイオン、ナトリウムイオン、カリウムイオン及び四級アルキルアンモニウムイオンからなる群より選ばれる少なくとも1種のイオンであることを特徴とする請求項10又は11に記載の非水系電解液。
- 前記テトラフルオロイオン性錯体(1-Tetra)の含有量の、前記ジフルオロイオン性錯体(1-Cis)の質量に対する割合が、0.02以上0.25以下である、請求項10~12のいずれか1項に記載の非水系電解液。
- 前記非水有機溶媒が、環状カーボネート及び鎖状カーボネートからなる群から選ばれる少なくとも1種を含むことを特徴とする請求項1~13のいずれか1項に記載の非水系電解液。
- 前記環状カーボネートが、エチレンカーボネート及びプロピレンカーボネートからなる群から選ばれる少なくとも1種であり、前記鎖状カーボネートが、エチルメチルカーボネート、ジメチルカーボネート、ジエチルカーボネート及びメチルプロピルカーボネートからなる群から選ばれる少なくとも1種であることを特徴とする請求項14に記載の非水系電解液。
- 前記非水有機溶媒が、さらにエステル類、エーテル類、ラクトン類、ニトリル類、アミド類及びスルホン類からなる群から選ばれる少なくとも1種の化合物を含有することを特徴とする請求項14又は15に記載の非水系電解液。
- 前記電解質が、リチウム、ナトリウム、カリウム、及び四級アンモニウムからなる群から選ばれる少なくとも1種のカチオンと、ヘキサフルオロリン酸、テトラフルオロホウ酸、過塩素酸、ヘキサフルオロヒ酸、ヘキサフルオロアンチモン酸、トリフルオロメタンスルホン酸、ビス(トリフルオロメタンスルホニル)イミド、ビス(ペンタフルオロエタンスルホニル)イミド、(トリフルオロメタンスルホニル)(ペンタフルオロエタンスルホニル)イミド、ビス(フルオロスルホニル)イミド、(トリフルオロメタンスルホニル)(フルオロスルホニル)イミド、(ペンタフルオロエタンスルホニル)(フルオロスルホニル)イミド、トリス(トリフルオロメタンスルホニル)メチド、及びビス(ジフルオロホスホニル)イミドからなる群から選ばれる少なくとも1種のアニオンの対からなる塩であることを特徴とする請求項1~16のいずれか1項に記載の非水系電解液。
- 請求項1~17のいずれか1項に記載の非水系電解液と、正極と、負極と、セパレータとを備えた非水系電解液電池。
- (ア)請求項1から17のいずれかに記載の非水系電解液と、
(イ)少なくとも1種の酸化物及び/又はポリアニオン化合物を正極活物質として含む正極と、
(ウ)負極活物質を含む負極と、
(エ)ポリオレフィン又はセルロースを主成分とするセパレータとを備え、
前記正極活物質は、(A)ニッケル、マンガン、コバルトの少なくとも1種以上の金属を含有し、層状構造を有するリチウム遷移金属複合酸化物、(B)スピネル構造を有するリチウムマンガン複合酸化物、(C)リチウム含有オリビン型リン酸塩及び(D)層状岩塩型構造を有するリチウム過剰層状遷移金属酸化物からなる群から選択される少なくとも1種以上であり、
前記負極活物質は、(E)X線回折における格子面(002面)のd値が0.340nm以下の炭素材料、(F)X線回折における格子面(002面)のd値が0.340nmを超える炭素材料、(G)Si、Sn、Alから選ばれる1種以上の金属の酸化物、(H)Si、Sn、Alから選ばれる1種以上の金属若しくはこれら金属を含む合金又はこれら金属若しくは合金とリチウムとの合金、及び(I)リチウムチタン酸化物からなる群から選択される少なくとも1種以上である、非水系電解液電池。
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Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2017026181A1 (ja) * | 2015-08-12 | 2017-02-16 | セントラル硝子株式会社 | 非水系電解液及びそれを用いた非水系電解液電池 |
JP2017216040A (ja) * | 2016-05-30 | 2017-12-07 | セントラル硝子株式会社 | 非水系電解液二次電池用電解液及びそれを用いた非水系電解液二次電池 |
WO2018008650A1 (ja) * | 2016-07-06 | 2018-01-11 | セントラル硝子株式会社 | 非水系電解液及びそれを用いた非水系電解液電池 |
Families Citing this family (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP6746099B2 (ja) * | 2016-11-07 | 2020-08-26 | 株式会社Gsユアサ | 非水電解質二次電池用活物質、非水電解質二次電池用活物質の製造方法、非水電解質二次電池用正極及び非水電解質二次電池 |
CN108091760B (zh) * | 2016-11-23 | 2019-11-22 | 清华大学 | 调控含氢过渡金属氧化物相变的方法 |
JP6880748B2 (ja) * | 2017-01-10 | 2021-06-02 | 株式会社リコー | 光電変換素子及び太陽電池 |
CN109687026B (zh) * | 2019-03-04 | 2020-12-01 | 杉杉新材料(衢州)有限公司 | 一种高压三元锂离子电池电解液及含该电解液的锂离子电池 |
CN112670576A (zh) * | 2020-12-23 | 2021-04-16 | 远景动力技术(江苏)有限公司 | 一种兼具长循环与高温特性的非水电解液及锂离子电池 |
CN113206295A (zh) * | 2021-04-30 | 2021-08-03 | 宁德新能源科技有限公司 | 电化学装置和包含其的电子设备 |
EP4191740A1 (de) * | 2021-12-01 | 2023-06-07 | Hilti Aktiengesellschaft | Verfahren zum laden eines akkumulators einer mobilen werkzeugmaschine sowie ladevorrichtung |
Citations (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2003137890A (ja) * | 2001-11-05 | 2003-05-14 | Central Glass Co Ltd | イオン性金属錯体の合成法 |
JP2007035357A (ja) * | 2005-07-25 | 2007-02-08 | Toyota Central Res & Dev Lab Inc | リチウムイオン二次電池 |
JP2008004503A (ja) * | 2006-06-26 | 2008-01-10 | Sony Corp | 非水電解質組成物及び非水電解質二次電池 |
WO2010067549A1 (ja) * | 2008-12-12 | 2010-06-17 | 株式会社村田製作所 | 非水電解液二次電池 |
WO2011125397A1 (ja) * | 2010-04-06 | 2011-10-13 | セントラル硝子株式会社 | 非水電解液電池用電解液及びこれを用いる非水電解液電池 |
WO2012102259A1 (ja) * | 2011-01-25 | 2012-08-02 | 株式会社 村田製作所 | 非水電解液二次電池 |
JP2013232417A (ja) * | 2012-04-30 | 2013-11-14 | Samsung Sdi Co Ltd | リチウム二次電池用電解液およびリチウム二次電池 |
WO2013180174A1 (ja) * | 2012-05-30 | 2013-12-05 | セントラル硝子株式会社 | シュウ酸を配位子とする金属錯体精製物及び該金属錯体の非水溶媒精製溶液の製造方法 |
WO2014157591A1 (ja) * | 2013-03-27 | 2014-10-02 | 三菱化学株式会社 | 非水系電解液及びそれを用いた非水系電解液電池 |
WO2015174455A1 (ja) * | 2014-05-14 | 2015-11-19 | 宇部興産株式会社 | 非水電解液、それを用いた蓄電デバイス、及びそれに用いるリチウム塩 |
Family Cites Families (38)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP3066126B2 (ja) | 1991-09-10 | 2000-07-17 | 三洋電機株式会社 | 非水系電解液電池 |
JPH07176323A (ja) | 1993-12-21 | 1995-07-14 | Mitsubishi Cable Ind Ltd | Li二次電池用電解液及び負極 |
FR2719161B1 (fr) | 1994-04-22 | 1996-08-02 | Accumulateurs Fixes | Générateur électrochimique rechargeable au lithium à anode de carbone. |
DE19829030C1 (de) | 1998-06-30 | 1999-10-07 | Metallgesellschaft Ag | Lithium-bisoxalatoborat, Verfahren zu dessen Herstellung und dessen Verwendung |
JP2001006729A (ja) | 1999-06-18 | 2001-01-12 | Mitsubishi Chemicals Corp | 非水系電解液二次電池 |
CN1181592C (zh) | 1999-06-18 | 2004-12-22 | 三菱化学株式会社 | 非水系电解液蓄电池 |
DE19933898A1 (de) | 1999-07-22 | 2001-02-01 | Chemetall Gmbh | Tris(oxalato)phosphate, Verfahren zu deren Herstellung und deren Verwendung |
JP2001057235A (ja) | 1999-08-19 | 2001-02-27 | Mitsui Chemicals Inc | 非水電解液および非水電解液二次電池 |
US6680143B2 (en) | 2000-06-22 | 2004-01-20 | The University Of Chicago | Lithium metal oxide electrodes for lithium cells and batteries |
JP3722685B2 (ja) | 2000-10-03 | 2005-11-30 | セントラル硝子株式会社 | 電気化学ディバイス用電解質及びそれを用いた電池 |
DE60143070D1 (de) | 2000-10-03 | 2010-10-28 | Central Glass Co Ltd | Elektrolyt für elektrochemische Vorrichtung |
JP4973825B2 (ja) | 2000-11-14 | 2012-07-11 | 戸田工業株式会社 | 非水電解質二次電池用正極活物質の製造法、非水電解質二次電池 |
JP4190162B2 (ja) | 2001-03-01 | 2008-12-03 | 三井化学株式会社 | 非水電解液、それを用いた二次電池、および電解液用添加剤 |
JP2003115324A (ja) | 2001-10-04 | 2003-04-18 | Japan Storage Battery Co Ltd | 非水電解質電池。 |
US6849752B2 (en) | 2001-11-05 | 2005-02-01 | Central Glass Company, Ltd. | Process for synthesizing ionic metal complex |
JP3417411B2 (ja) | 2002-05-17 | 2003-06-16 | 宇部興産株式会社 | 非水電解液及びリチウム二次電池 |
GB2395059B (en) | 2002-11-05 | 2005-03-16 | Imp College Innovations Ltd | Structured silicon anode |
WO2004100293A1 (ja) | 2003-05-09 | 2004-11-18 | Sony Corporation | 負極活物質及びその製造方法、これを用いた非水電解質二次電池 |
JP4423888B2 (ja) | 2003-06-11 | 2010-03-03 | ソニー株式会社 | リチウムイオン二次電池用電解質およびそれを用いたリチウムイオン二次電池 |
JP2006196250A (ja) | 2005-01-12 | 2006-07-27 | Sanyo Electric Co Ltd | リチウム二次電池 |
KR20060042201A (ko) | 2004-02-27 | 2006-05-12 | 산요덴키가부시키가이샤 | 리튬 2차 전지 |
JP2007018883A (ja) | 2005-07-07 | 2007-01-25 | Toshiba Corp | 負極活物質、非水電解質電池及び電池パック |
GB0601319D0 (en) | 2006-01-23 | 2006-03-01 | Imp Innovations Ltd | A method of fabricating pillars composed of silicon-based material |
JP2007242411A (ja) | 2006-03-08 | 2007-09-20 | Sony Corp | 電池及び電解液組成物 |
JP4605133B2 (ja) | 2006-06-05 | 2011-01-05 | ソニー株式会社 | 非水電解質およびこれを用いた非水電解質電池、並びに非水電解質の製造方法 |
JP2007335143A (ja) | 2006-06-13 | 2007-12-27 | Toyota Central Res & Dev Lab Inc | リチウムイオン二次電池 |
JP5256816B2 (ja) | 2007-03-27 | 2013-08-07 | 学校法人神奈川大学 | リチウムイオン電池用正極材料 |
WO2009063613A1 (ja) | 2007-11-12 | 2009-05-22 | Toda Kogyo Corporation | 非水電解液二次電池用Li-Ni系複合酸化物粒子粉末及びその製造方法、並びに非水電解質二次電池 |
JP5258353B2 (ja) * | 2008-03-31 | 2013-08-07 | 三洋電機株式会社 | 非水電解質二次電池 |
JP5278442B2 (ja) * | 2009-01-06 | 2013-09-04 | 株式会社村田製作所 | 非水電解液二次電池 |
KR101930558B1 (ko) | 2010-05-12 | 2018-12-18 | 미쯔비시 케미컬 주식회사 | 비수계 전해액 및 비수계 전해액 2차 전지 |
JP5989634B2 (ja) | 2011-02-28 | 2016-09-07 | 三洋電機株式会社 | 非水電解液二次電池 |
JP5988134B2 (ja) * | 2011-05-11 | 2016-09-07 | 株式会社Gsユアサ | 蓄電素子 |
JP2013030284A (ja) | 2011-07-26 | 2013-02-07 | Mitsubishi Chemicals Corp | 非水系電解液電池 |
JP5796417B2 (ja) * | 2011-08-31 | 2015-10-21 | セントラル硝子株式会社 | 非水電解液電池用電解液及び非水電解液電池 |
US9865872B2 (en) | 2012-02-06 | 2018-01-09 | Nec Corporation | Lithium-ion battery and method for producing same |
WO2013132824A1 (ja) | 2012-03-05 | 2013-09-12 | 株式会社豊田自動織機 | リチウムイオン二次電池 |
CN104685698B (zh) | 2012-08-27 | 2017-04-19 | 三洋电机株式会社 | 非水电解质二次电池 |
-
2015
- 2015-01-23 JP JP2015011735A patent/JP6007994B2/ja active Active
- 2015-12-28 CN CN201580073997.6A patent/CN107210485B/zh active Active
- 2015-12-28 EP EP15878968.5A patent/EP3246983B1/en active Active
- 2015-12-28 WO PCT/JP2015/086564 patent/WO2016117280A1/ja active Application Filing
- 2015-12-28 KR KR1020177023184A patent/KR101958865B1/ko active IP Right Grant
- 2015-12-28 HU HUE15878968A patent/HUE050023T2/hu unknown
- 2015-12-28 PL PL15878968T patent/PL3246983T3/pl unknown
- 2015-12-28 US US15/545,171 patent/US10186733B2/en active Active
-
2016
- 2016-01-20 TW TW105101757A patent/TW201640733A/zh unknown
Patent Citations (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2003137890A (ja) * | 2001-11-05 | 2003-05-14 | Central Glass Co Ltd | イオン性金属錯体の合成法 |
JP2007035357A (ja) * | 2005-07-25 | 2007-02-08 | Toyota Central Res & Dev Lab Inc | リチウムイオン二次電池 |
JP2008004503A (ja) * | 2006-06-26 | 2008-01-10 | Sony Corp | 非水電解質組成物及び非水電解質二次電池 |
WO2010067549A1 (ja) * | 2008-12-12 | 2010-06-17 | 株式会社村田製作所 | 非水電解液二次電池 |
WO2011125397A1 (ja) * | 2010-04-06 | 2011-10-13 | セントラル硝子株式会社 | 非水電解液電池用電解液及びこれを用いる非水電解液電池 |
WO2012102259A1 (ja) * | 2011-01-25 | 2012-08-02 | 株式会社 村田製作所 | 非水電解液二次電池 |
JP2013232417A (ja) * | 2012-04-30 | 2013-11-14 | Samsung Sdi Co Ltd | リチウム二次電池用電解液およびリチウム二次電池 |
WO2013180174A1 (ja) * | 2012-05-30 | 2013-12-05 | セントラル硝子株式会社 | シュウ酸を配位子とする金属錯体精製物及び該金属錯体の非水溶媒精製溶液の製造方法 |
WO2014157591A1 (ja) * | 2013-03-27 | 2014-10-02 | 三菱化学株式会社 | 非水系電解液及びそれを用いた非水系電解液電池 |
WO2015174455A1 (ja) * | 2014-05-14 | 2015-11-19 | 宇部興産株式会社 | 非水電解液、それを用いた蓄電デバイス、及びそれに用いるリチウム塩 |
Non-Patent Citations (1)
Title |
---|
See also references of EP3246983A4 * |
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2017026181A1 (ja) * | 2015-08-12 | 2017-02-16 | セントラル硝子株式会社 | 非水系電解液及びそれを用いた非水系電解液電池 |
JP2017037808A (ja) * | 2015-08-12 | 2017-02-16 | セントラル硝子株式会社 | 非水電解液二次電池用電解液及びそれを用いた非水電解液二次電池 |
US11114693B2 (en) | 2015-08-12 | 2021-09-07 | Central Glass Company, Ltd. | Electrolytic solution for nonaqueous electrolytic solution secondary batteries and nonaqueous electrolytic solution secondary battery |
JP2017216040A (ja) * | 2016-05-30 | 2017-12-07 | セントラル硝子株式会社 | 非水系電解液二次電池用電解液及びそれを用いた非水系電解液二次電池 |
WO2017208944A1 (ja) * | 2016-05-30 | 2017-12-07 | セントラル硝子株式会社 | 非水系電解液及びそれを用いた非水系電解液電池 |
US10991983B2 (en) | 2016-05-30 | 2021-04-27 | Central Glass Company Limited | Nonaqueous electrolytic solution and nonaqueous electrolytic solution secondary battery |
WO2018008650A1 (ja) * | 2016-07-06 | 2018-01-11 | セントラル硝子株式会社 | 非水系電解液及びそれを用いた非水系電解液電池 |
JP2018014319A (ja) * | 2016-07-06 | 2018-01-25 | セントラル硝子株式会社 | 非水系電解液及びそれを用いた非水系電解液二次電池 |
US11101499B2 (en) | 2016-07-06 | 2021-08-24 | Central Glass Company Limited | Nonaqueous electrolytic solution and nonaqueous electrolytic solution secondary battery |
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US10186733B2 (en) | 2019-01-22 |
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US20180241082A1 (en) | 2018-08-23 |
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