Battery

Abstract

The present invention provides a battery which is capable of achieving sufficiently high density of energy by increasing the battery voltage (or the output voltage).　Provided is a battery which comprises a positive electrode 1, a negative electrode 2, an electrolyte solution 3, and a separator 4. The separator 4 is a microporous film. The electrolyte solution 3 is a nonaqueous electrolyte solution which is composed of a positive electrode electrolyte solution 31 that is in contact with the positive electrode 1 and a negative electrode electrolyte solution 32 that is in contact with the negative electrode 2, the positive electrode electrolyte solution 31 and the negative electrode electrolyte solution 32 being arranged so that the separator 4 is sandwiched therebetween. The positive electrode electrolyte solution 31 and the negative electrode electrolyte solution 32 each contain a metal salt of a metal that is selected from the group consisting of alkali metals and alkaline earth metals, and a solvent that dissolves the metal salt. The activity of ions involved in a charge / discharge reaction in the positive electrode electrolyte solution 31 is higher than the activity of ions involved in a charge / discharge reaction in the negative electrode electrolyte solution 32.

Description

battery

[0001] This invention relates to batteries such as non-aqueous secondary batteries.

[0002] In recent years, development of non-aqueous secondary batteries has progressed as a power source for applications requiring high energy density, such as portable electronic devices, electric vehicles, and large-scale energy storage. Furthermore, the diversification of applications for devices using non-aqueous secondary batteries is expanding, and the demand for higher energy density is increasing year by year.

[0003] Non-aqueous secondary batteries comprise a positive electrode, a negative electrode, and a non-aqueous electrolyte, and various studies have been conducted regarding their battery configuration (for example, Patent Documents 1 to 6). In such non-aqueous secondary batteries, the battery voltage (or output voltage) based on the potential difference between the positive electrode potential and the negative electrode potential is generally determined predominantly by the combination of the positive electrode active material and the negative electrode active material.

[0004] Japanese Patent No. 02977252 WO2022 / 210698 WO2020 / 175555 Japanese Patent Publication No. 2017-139068 Japanese Patent Publication No. 2020-177890 Japanese Patent No. 5614431

[0005] However, conventional technology limits the combinations of positive electrode active materials and negative electrode active materials from the standpoint of reliability and other factors. On the other hand, as the applications of devices using non-aqueous secondary batteries diversify and the demand for higher energy density increases year by year, conventional technology has limitations in improving energy density.

[0006] The present invention aims to provide a battery that can sufficiently achieve high energy density by increasing the battery voltage (or output voltage).

[0007] The inventors of the present invention have discovered that a voltage boosting effect (more specifically, an effect that achieves a higher voltage) can be obtained in a battery by isolating specific positive electrode electrolytes and negative electrode electrolytes with a microporous membrane.

[0008] The present invention relates to a battery having a positive electrode, a negative electrode, an electrolyte, and a separator, wherein the separator is a microporous membrane, the electrolyte is a non-aqueous electrolyte composed of a positive electrode electrolyte in contact with the positive electrode and a negative electrode electrolyte in contact with the negative electrode, arranged on either side of the separator, each of the positive electrode electrolyte and the negative electrode electrolyte contains a metal salt of a metal selected from the group consisting of alkali metals and alkaline earth metals and a solvent for dissolving the metal salt, and the activity of charge-discharge reaction participating ions in the positive electrode electrolyte is greater than the activity of charge-discharge reaction participating ions in the negative electrode electrolyte.

[0009] The present invention also relates to a battery having a positive electrode, a negative electrode, an electrolyte, and a separator, wherein the separator is a microporous membrane, the electrolyte is a non-aqueous electrolyte composed of a positive electrode electrolyte in contact with the positive electrode and a negative electrode electrolyte in contact with the negative electrode, arranged on either side of the separator, each of the positive electrode electrolyte and the negative electrode electrolyte contains a metal salt of a metal selected from the group consisting of alkali metals and alkaline earth metals and a solvent for dissolving the metal salt, and the potential FVp of charge-discharge reaction participating ions in the positive electrode electrolyte is higher than the potential FVn of charge-discharge reaction participating ions in the negative electrode electrolyte.

[0010] The battery according to the present invention can achieve a higher battery voltage (or output voltage), and as a result, can sufficiently achieve high energy density.

[0011] Figure 1 shows a schematic cross-sectional view of an example of a battery according to one embodiment of the present invention. Figure 2 shows a schematic view showing the stacked structure of an example of a battery according to one embodiment of the present invention. Figure 3A is a schematic cross-sectional view illustrating an example of a manufacturing method for obtaining a secondary battery of the present invention having gel-like positive and negative electrode electrolytes. Figure 3B is a schematic cross-sectional view illustrating an example of a manufacturing method for obtaining a secondary battery of the present invention having gel-like positive and negative electrode electrolytes. Figure 3C is a schematic cross-sectional view illustrating an example of a manufacturing method for obtaining a secondary battery of the present invention having gel-like positive and negative electrode electrolytes. Figure 3D is a schematic cross-sectional view illustrating an example of a manufacturing method for obtaining a secondary battery of the present invention having gel-like positive and negative electrode electrolytes. Figure 4 shows schematic cross-sectional views and schematic plan views of the positive and negative electrodes manufactured in the examples. Figure 5 is a schematic cross-sectional view of a secondary battery manufactured in the examples (particularly experimental example A), which is a schematic cross-sectional view of an example of a secondary battery of the present invention having non-gel-like positive and negative electrode electrolytes. Figure 6 is a schematic cross-sectional view of a secondary battery manufactured in an example (particularly experimental example B), and is a schematic cross-sectional view of an example of a secondary battery of the present invention having gel-like positive electrode electrolytes and negative electrode electrolytes.

[0012] [Battery] The battery according to the present invention may have any structure as long as it has a positive electrode, a negative electrode, an electrolyte, and a separator, and may be, for example, a so-called primary battery or a secondary battery. A "primary battery" refers to a battery that cannot be repeatedly charged and discharged. A "secondary battery" refers to a battery that can be repeatedly charged and discharged. The following will describe in detail the case in which the battery of the present invention is a secondary battery, but the secondary battery according to one embodiment of the present invention is not overly bound by its name, and may also include electrochemical devices such as energy storage devices. In the following, the case in which the secondary battery of the present invention is a lithium-ion secondary battery in which charging and discharging are mainly performed by the movement of lithium ions between the positive electrode and the negative electrode will be described in detail. The ions involved in the charge-discharge reaction (hereinafter sometimes referred to as "charge-discharge reaction involved ions") are not particularly limited as long as charging and discharging are possible, and may be, for example, sodium ions, potassium ions, calcium ions, or magnesium ions.

[0013] In describing the secondary battery according to the present invention in detail below, the drawings will be referenced as necessary. However, the various elements in the drawings are shown schematically and illustratively for the purpose of understanding the present invention, and unless otherwise specified, their appearance and dimensional ratios may differ from those of the actual product. The terms “up and down” and “left and right” used directly or indirectly in this specification correspond to the up and down and left and right directions in the drawings, respectively. Unless otherwise specified, the same reference numerals or symbols indicate the same component and / or part or have the same meaning. In a preferred embodiment, the downward vertical direction (i.e., the direction in which gravity acts) can be considered as “downward,” and the opposite direction as “upward.” In this specification, terms indicating relationships between elements (e.g., “parallel,” “orthogonal,” “perpendicular,” etc.) and terms indicating the shape of elements or relationships between elements mean not only strictly defined embodiments, but also substantially equivalent ranges, for example, ranges including differences of a few percent.

[0014] The battery of the present invention, for example, has a positive electrode 1, a negative electrode 2, an electrolyte 3, and a separator 4, as shown in Figure 1. Figure 1 shows a schematic cross-sectional view of a battery according to one embodiment of the present invention.

[0015] More specifically, the battery of the present invention has, as shown in Figure 1, a positive electrode 1; a negative electrode 2; an electrolyte 3 containing a positive electrode electrolyte 31 and a negative electrode electrolyte 32; and a separator 4 disposed between the positive electrode 1 and the negative electrode 2, which separates the positive electrode electrolyte 31 and the negative electrode electrolyte 32.

[0016] In the battery of the present invention (particularly a secondary battery), the mixing of the positive electrode electrolyte 31 and the negative electrode electrolyte 32 is suppressed by the separator 4, which is a microporous membrane. Metal ions, which are ions involved in the charge-discharge reaction, permeate the separator 4 between the positive electrode electrolyte 31 and the negative electrode electrolyte 32 and are responsible for the transfer of charge.

[0017] (Electrolyte) The electrolyte 3 is a non-aqueous electrolyte composed of (or arranged) a "positive electrode electrolyte 31 in contact with the positive electrode 1" and a "negative electrode electrolyte 32 in contact with the negative electrode 2," which are placed on either side of the separator 4. In the battery of the present invention, the positive electrode electrolyte 31 and the negative electrode electrolyte 32 are separated by the separator 4, and metal ions are allowed to permeate the separator 4 as charge-discharge reaction participating ions. Charge-discharge reaction participating ions are ions that contribute to the charge-discharge reaction of the active material, and more specifically, are metal ions that are primarily responsible for the charge-discharge reaction. Charge-discharge reaction participating ions may be, for example, metal ions such as lithium ions, sodium ions, potassium ions, calcium ions, or magnesium ions.

[0018] Each of the positive electrode electrolyte 31 and the negative electrode electrolyte 32 contains an electrolyte and a solvent for dissolving the electrolyte.

[0019] The activity of the charge-discharge reaction-participating ions in the positive electrode electrolyte 31 is greater than the activity of the charge-discharge reaction-participating ions in the negative electrode electrolyte 32. By making the activity of the charge-discharge reaction-participating ions in the positive electrode electrolyte greater than the activity of the charge-discharge reaction-participating ions in the negative electrode electrolyte, a voltage boosting effect can be obtained in the battery, and as a result, the capacity energy density can be improved. The activity of the charge-discharge reaction-participating ions is a characteristic (or characteristic value) based on the force that binds the charge-discharge reaction-participating ions in the electrolyte. The greater the activity of the charge-discharge reaction-participating ions, the smaller the binding force on the charge-discharge reaction-participating ions. The binding force on the charge-discharge reaction-participating ions is the binding force that the charge-discharge reaction-participating ions experience, and is the binding force that the charge-discharge reaction-participating ions experience due to the solvent in the electrolyte.

[0020] This invention makes the activity of charge-discharge reaction-participating ions in the positive electrode electrolyte greater than the activity of charge-discharge reaction-participating ions in the negative electrode electrolyte. As a result, the binding force of charge-discharge reaction-participating ions in the positive electrode electrolyte is smaller than that of charge-discharge reaction-participating ions in the negative electrode electrolyte. This difference is then extracted externally as a potential difference between the positive electrode potential and the negative electrode potential. Consequently, the battery voltage can be increased.

[0021] The activity of ions involved in the charge-discharge reaction in the electrolyte can be controlled by the concentration of the electrolyte and the number of solvent donors in the electrolyte. More specifically, the activity of ions involved in the charge-discharge reaction in the positive electrode electrolyte and the negative electrode electrolyte can be controlled independently by the concentration of the electrolyte and / or the number of solvent donors in each of those electrolytes.

[0022] For example, in both the positive and negative electrode electrolytes, increasing the electrolyte concentration increases the activity of the ions involved in the charge-discharge reaction in each electrolyte. On the other hand, in both the positive and negative electrode electrolytes, decreasing the electrolyte concentration decreases the activity of the ions involved in the charge-discharge reaction in each electrolyte.

[0023] Furthermore, for example, in both the positive and negative electrode electrolytes, increasing the number of solvent donors lowers the activity of the ions involved in the charge-discharge reaction in each electrolyte. On the other hand, in both the positive and negative electrode electrolytes, decreasing the number of solvent donors lowers the activity of the ions involved in the charge-discharge reaction in each electrolyte.

[0024] The electrolyte concentration refers to the concentration of ions involved in the charge-discharge reaction relative to the solvent in the electrolyte solution. The electrolyte concentration may also be expressed as the molar ratio of charge-discharge reaction ions to solvent.

[0025] The number of donors in a solvent is an indicator of the strength with which the solvent binds to metal ions (e.g., lithium ions), and may be based on its solvation-forming properties (e.g., solvation ability or solvating power). For example, the larger the number of donors in a solvent, the more readily it binds to metal ions and the higher its solvation ability. Conversely, the smaller the number of donors in a solvent, the less readily it binds to metal ions and the lower its solvation ability.

[0026] In this specification, the donor numbers are those listed in the reference "Eur. Chem. Bull. 4(2), 92-97 (2015), Table 2". Specifically, the donor numbers for major solvents are as follows. In the following description, the solvent compound name and its donor number are listed in that order. The unit for donor numbers is "kcal / mol".

[0027] 1,2-Dichloroethane 0 Hexane 0 Heptane 0 Tetrachloromethane 0 Benzene 0.1 Toluene 0.1 Thionyl chloride 0.4 Dichloromethane 1 m-Dichlorobenzene 2 Carbon disulfide 2 Benzoyl chloride 2.3 Nitromethane 2.7 Fluorobenzene 3 o-Dichlorobenzene 3 Bromobenzene 3 Chlorobenzene 3.3 Chloroform 4 Iodobenzene 4 Nitrobenzene 4.4 Nitroethane 5

[0028] m-xylene 5 p-xylene 5 styrene 5 2-chloroethanol 5 furan 6 ethylbenzene 6 cumene 6 phenethole 8 anisole 9 monochloroacetonitrile 9.6 mesitylene 10 acetic anhydride 10.5 phenol 11 biacetyl 11 methyl propanoate 11 phosphorus oxychloride 11.7 benzonitrile 11.9 ethyl chloroacetate 13 acetonitrile 14.1 dioxane 14.8

[0029] Sulfolane 14.8, 3-Pentanone 15, Ethyl Benzoate 15, Acetophenone 15, Butyl Acetate 15, 4-Methyl-2-oxo-1,3-Dioxolane 15.1, Benzyl Cyanide 15.1, Propylene Carbonate 15.1, i-Butanenitrile 15.4, Di(2-Chloroethyl) Ether 16, Propyl Acetate 16, Benzaldehyde 16, Methyl Isobutyl Ketone 16, Diethyl Carbonate 16, Propanenitrile 16.1, Methyl Acetate 16.3, Ethylene Carbonate 16.4, Butanenitrile 16.6

[0030] 2-Propanone (acetone) 17 t-Butyl-methyl ketone 17 Ethyl propanoate 17.1 Methyl i-propyl ketone 17.1 Ethyl acetate 17.1 Dimethyl carbonate 17.2 2 Butanone 17.4 Water 18 Cyclopentanone 18 Cyclohexanone 18 2-Methyltetrahydrofuran 18 4-Butyrolactone 18 Di-n-propyl ether 18 Di-i-propyl ether 19 Di-n-propyl ether 19 Formic acid 19 Methanol 19 Glycerol 19 Dibenzyl ether 19 Diethyl ether 19.2

[0031] Ethanol 19.2, Butanol 19.5, Propanol 19.8, Tetrahydrofuran 20, Acetic acid 20, 1,2-Ethanediol 20, 1,2-Dimethoxyethane 20, Tetrahydrofuran 20, 2-Propanol 21.1, 1,3-Dioxolane 21.2, 2-Methyl-2-Propanol 21.9, Tetrahydropyran 22, 2-Phenylenethanol 23, Benzyl alcohol 23, Trimethyl phosphate 23, Tributyl phosphate 23.7, 1,8-Cineole 24, Formamide 24, n-Pentanol 25, Triethyl phosphate 26, N,N-Dimethylformamide 26.6

[0032] N-methylformamide 27 N,N-dimethylaniline 27 N-methyl-ε-caprolactam 27.1 N-methylpyrrolidone (NMP) 27.3 N,N-dimethylacetamide 27.8 1,3-dimethylimidazolidine-2-one (DMEU) n-butanol 29.0 (NMe2)(EtO)2P=O 29.5 N,N,N',N'-tetramethylurea 29.6 Dimethyl sulfoxide 29.8 Methanol 30 n-propanol 30 n-hexanol 30 N,N-diethylformamide 30.9 o-chloroaniline 31

[0033] n-decanol 31 Dibutyl sulfoxide 31 Quinoline 32 Ethanol 32 Isopentanol 32 n-Octanol 32 N,N-Diethylacetamide 32.2 3,4,5,6-Tetrahydro-1,3-Dimethylpyrimidine-2(1H)-one (DMPU) 33 N-Methylaniline 33 Pyridine 33.1 4-Methylpyridine 34 Pyridine oxide 34.4 Aniline 35 Isopropanol 36 p-Methylpyridine N-Oxide 36.3 (NMe2)2(EtO)P=O 36.4 (NEt2)3P=O 36.6 Isobutanol 37 (NMe2)2(NEt2)2P=O 37.8 n-Butanol 38

[0034] (NMe2)2(pyrrolidino)P=O (MPPA) 38.0 HMPA or HMPT 38.8 3-methylpyridine 39 Dimethyl sulfide 40 (NEt2)2(pyrrolidino)P=O 40.2 (NMe2)(NHEt)2P=O 40.6 (piperidino)3P=O 40.9 Diethyl sulfide 41 (NMe2)2(azetidino)P=O 41.1 (NMe2)2(NHEt)P=O 41.2 n-butylamine 42 (NMe)2(MeN-CH2-CH2-NMe)P=O 42.1 (NMe2)(azetidino)2P=O 42.3 (NEt2)(pyrrolidino)2P=O 42.6

[0035] (Azetidino)3P=O 43 t-Pentanol 44 Hydrazine 44 (NMe2)(pyrrolidino)2P=O (DPPA) 45.4 (pyrrolidino)3P=O (TPPA or TPPT) 47.2 (NHEt)3P=O 47.3 (NMe2)2(aziridino)P=O 48.6 (NMe2)(aziridino)2P=O 49.1 Diethylamine 50 Tri-n-butylamine 50 (aziridino)3P=O (TEPA) 50 Piperidine 51 Trioctylamine N-oxide 52.3 Ammonia 59 Triethylamine 61

[0036] The number of donors for solvents not listed in the examples above can be measured, for example, by the following method: Add SbCl to the solvent to be measured. ５ to 10 －３ The value obtained from measuring the heat of dissolution when dissolving to a mol / L solution (kcal / mol) may be used as the donor number.

[0037] The electrolyte concentrations and solvent donor numbers of the positive electrode electrolyte and the negative electrode electrolyte are not particularly limited, as long as the activity of the charge-discharge reaction-involved ions in the positive electrode electrolyte is greater than the activity of the charge-discharge reaction-involved ions in the negative electrode electrolyte, and may be within the following ranges, for example.

[0038] The electrolyte concentration (particularly the charge-discharge reaction-participating ion concentration) Cp of the positive electrode electrolyte is not particularly limited, as long as the activity of the charge-discharge reaction-participating ions in the positive electrode electrolyte is greater than the activity of the charge-discharge reaction-participating ions in the negative electrode electrolyte. For example, the molar ratio of charge-discharge reaction-participating ions / solvent may be 0.01 or more and 0.70 or less. From the viewpoint of further increasing the battery voltage, it is preferably 0.08 or more and 0.67 or less, more preferably 0.10 or more and 0.67 or less, even more preferably 0.20 or more and 0.67 or less, sufficiently preferably 0.30 or more and 0.67 or less, even more sufficiently preferably 0.40 or more and 0.67 or less, particularly preferably 0.50 or more and 0.67 or less, and most preferably 0.55 or more and 0.67 or less. The electrolyte concentration of the positive electrode electrolyte may also be based on the total amount of electrolytes if the positive electrode electrolyte contains two or more types of electrolytes. The electrolyte concentration of the positive electrode electrolyte may also be based on the total amount of solvents if the positive electrode electrolyte contains two or more types of solvents.

[0039] The electrolyte concentration (especially the charge-discharge reaction-participating ion concentration) Cn of the negative electrode electrolyte is not particularly limited, as long as the activity of the charge-discharge reaction-participating ions in the positive electrode electrolyte is greater than the activity of the charge-discharge reaction-participating ions in the negative electrode electrolyte. For example, the molar ratio of electrolyte (especially charge-discharge reaction-participating ions) / solvent may be 0.01 or more and 0.50 or less. From the viewpoint of further increasing the battery voltage, it is preferably 0.02 or more and 0.40 or less, more preferably 0.03 or more and 0.30 or less, even more preferably 0.04 or more and 0.20 or less, sufficiently preferably 0.05 or more and 0.15 or less, even more sufficiently preferably 0.06 or more and 0.14 or less, particularly preferably 0.07 or more and 0.12 or less, and most preferably 0.08 or more and 0.10 or less. The electrolyte concentration of the negative electrode electrolyte may also be based on the total amount of electrolytes if the negative electrode electrolyte contains two or more types of electrolytes. The electrolyte concentration of the negative electrode electrolyte may also be based on the total amount of solvents if the negative electrode electrolyte contains two or more types of solvents.

[0040] From the viewpoint of further increasing the battery voltage, the electrolyte concentration (particularly the concentration of ions involved in the charge-discharge reaction) Cp of the positive electrode electrolyte is preferably higher than the electrolyte concentration (particularly the concentration of ions involved in the charge-discharge reaction) Cn of the negative electrode electrolyte. The difference (Cp-Cn) between the electrolyte concentration (particularly the concentration of ions involved in the charge-discharge reaction) of the positive electrode electrolyte and the electrolyte concentration (particularly the concentration of ions involved in the charge-discharge reaction) of the negative electrode electrolyte is not particularly limited, but from the viewpoint of further increasing the battery voltage, it is preferably 0.10 to 0.69, more preferably 0.20 to 0.68, even more preferably 0.30 to 0.67, sufficiently preferably 0.40 to 0.66, even more preferably 0.45 to 0.65, particularly preferably 0.50 to 0.65, and most preferably 0.55 to 0.65.

[0041] The electrolyte concentrations (especially the concentrations of ions involved in the charge-discharge reaction) of the positive and negative electrode electrolytes can be measured by first identifying the types (molecular weights) of the electrolytes and solvents using nuclear magnetic resonance spectroscopy, infrared absorption spectroscopy, inductively coupled plasma emission spectroscopy, and gas chromatography, and then identifying the composition ratio by comparing the peak intensity with that of standard substances using the aforementioned measurement methods.

[0042] The number of solvent donors Dp in the positive electrode electrolyte is not particularly limited, as long as the activity of the charge-discharge reaction-involved ions in the positive electrode electrolyte is greater than the activity of the charge-discharge reaction-involved ions in the negative electrode electrolyte. For example, it may be 6.0 or more and 20.0 or less. From the viewpoint of further increasing the battery voltage, it is preferably 8.0 or more and 19.0 or less, more preferably 10.0 or more and 18.0 or less, even more preferably 12.0 or more and 17.0 or less, sufficiently preferably 14.0 or more and 16.0 or less, and even more preferably 14.5 or more and 15.5 or less. The number of solvent donors in the positive electrode electrolyte is the number of donors of the solvent with the largest donor number when the positive electrode electrolyte contains two or more types of solvents.

[0043] The number of solvent donors Dn in the negative electrode electrolyte is not particularly limited, as long as the activity of the charge-discharge reaction-involved ions in the positive electrode electrolyte is greater than the activity of the charge-discharge reaction-involved ions in the negative electrode electrolyte. For example, it may be 8.0 or more and 40.0 or less. From the viewpoint of further increasing the battery voltage, it is preferably 10.0 or more and 38.0 or less, more preferably 12.0 or more and 36.0 or less, even more preferably 14.0 or more and 34.0 or less, sufficiently preferably 16.0 or more and 32.0 or less, even more certainly preferably 19.0 or more and 30.0 or less, particularly preferably 22.0 or more and 30.0 or less, and most preferably 24.0 or more and 29.0 or less. The number of solvent donors in the negative electrode electrolyte is the number of donors of the solvent with the largest donor number when the negative electrode electrolyte contains two or more types of solvents.

[0044] From the viewpoint of further increasing the battery voltage, it is preferable that the number of solvent donors Dn in the negative electrode electrolyte is higher than the number of solvent donors Dp in the positive electrode electrolyte. The difference (Dn - Dp) between the number of solvent donors in the negative electrode electrolyte and the number of solvent donors in the positive electrode electrolyte is not particularly limited, but from the viewpoint of further increasing the battery voltage, it is preferably 0.1 to 20.0, more preferably 0.5 to 18.0, even more preferably 1.0 to 16.0, even more preferably 5.0 to 16.0, even more preferably 5.0 to 14.0, even more preferably 8.0 to 14.0, and even more preferably 11.0 to 14.0.

[0045] The types of solvents in the positive electrode electrolyte and the negative electrode electrolyte can be detected by analysis using methods such as nuclear magnetic resonance spectroscopy, infrared absorption spectroscopy, inductively coupled plasma emission spectroscopy, and gas chromatography, as described above.

[0046] In the present invention, the positive electrode electrolyte and the negative electrode electrolyte may have any one of the following relationships (I) to (IV) with respect to the molar ratio of charge-discharge contributing ions / solvent and the relative size of the number of solvent donors: (I) Cp > Cn and Dp < Dn; (II) Cp = Cn and Dp < Dn; (III) Cp < Cn and Dp < Dn; and (IV) Cp > Cn and Dp = Dn.

[0047] In the present invention, the positive electrode electrolyte and the negative electrode electrolyte preferably have one of the relationships (I) to (III), more preferably relationship (I) or (II), and even more preferably relationship (I), from the viewpoint of further increasing the battery voltage.

[0048] The activity of ions involved in the charge-discharge reaction in the electrolyte can be measured as the charge-discharge reaction ion potential, with the redox potential of ferrocene as the reference. For example, when the charge-discharge reaction ion is Li ions, ferrocene was added to each electrolyte so that it had a concentration of 1 mMol / L, which exhibits a constant redox potential regardless of the type of electrolyte, in the working electrode Pt / positive electrode electrolyte + ferrocene / counter electrode lithium and the working electrode Pt / negative electrode electrolyte + ferrocene / counter electrode lithium. The dissolution potential of lithium and the redox potential of ferrocene were measured by cyclic voltammetry. The "lithium deposition dissolution potential - ferrocene redox potential" can be compared for the positive electrode electrolyte and the negative electrode electrolyte. For example, the greater the activity of the ions involved in the charge-discharge reaction in the electrolyte, the greater the potential of the ions involved in the charge-discharge reaction in that electrolyte. Also, for example, the smaller the activity of the ions involved in the charge-discharge reaction in the electrolyte, the smaller the potential of the ions involved in the charge-discharge reaction in that electrolyte. Therefore, the potential of the charge-discharge reaction-participating ions in the electrolyte can also be controlled by the same method as the method for controlling the activity of the charge-discharge reaction-participating ions in the electrolyte described above. More specifically, the potentials of the charge-discharge reaction-participating ions in the positive electrode electrolyte and the negative electrode electrolyte can each be controlled independently by the concentration of the electrolyte and / or the number of solvent donors in each of the respective electrolytes.

[0049] For example, in both the positive and negative electrode electrolytes, increasing the electrolyte concentration increases the potential of the ions involved in the charge-discharge reaction in each electrolyte. On the other hand, in both the positive and negative electrode electrolytes, decreasing the electrolyte concentration decreases the potential of the ions involved in the charge-discharge reaction in each electrolyte.

[0050] Furthermore, for example, in both the positive and negative electrode electrolytes, increasing the number of solvent donors lowers the potential of the ions involved in the charge-discharge reaction in each electrolyte. On the other hand, in both the positive and negative electrode electrolytes, decreasing the number of solvent donors lowers the potential of the ions involved in the charge-discharge reaction in each electrolyte.

[0051] For example, Li ＋ When Li is an ion involved in the charge-discharge reaction, its potential is the potential relative to 1 mM ferrocene, and is the potential shown in the value of "The electrode potential of Li (V vs. Fc / Fc+)". ＋ When is the ion involved in the charge-discharge reaction, the potential of the ion involved in the charge-discharge reaction can be measured by the method described in the literature "Nature Energy 7, 1217-1224 (2022) Supplementary information, Table S1". More specifically, the redox potential of ferrocene is known as an internal standard potential that is not affected by the type of solvent, and the use of the redox potential of ferrocene was recommended by IUPAC in 1983 and is a method widely used in the fields of batteries and electrochemistry (RECOMMENDATIONS ON REPORTING ELECTRODE POTENTIALS IN NONAQUEOUS SOLVENTS, Pure & Appl. Chem. 56 (4), 461-466, (1984)).

[0052] Therefore, in the present invention, "the activity of charge-discharge reaction-participating ions in the positive electrode electrolyte is greater than the activity of charge-discharge reaction-participating ions in the negative electrode electrolyte" may mean "the potential of charge-discharge reaction-participating ions in the positive electrode electrolyte is higher than the potential of charge-discharge reaction-participating ions in the negative electrode electrolyte." For example, the potential of lithium ions in the positive electrode electrolyte is higher than the potential of lithium ions in the negative electrode electrolyte that is paired with the positive electrode electrolyte.

[0053] The potential of the ions involved in the charge-discharge reaction is measured using the following method. First, ferrocene (molecular weight 186.03) is dissolved in 100 mL of either the positive or negative electrode electrolyte to a concentration of 1 mmol / L. Next, using Pt as the working electrode, lithium metal as the counter electrode, and lithium metal as the reference electrode, cyclic voltammetry is performed to measure the potential value Ia that gives the oxidation current peak corresponding to lithium dissolution and the potential value Ib that gives the reduction current peak corresponding to lithium deposition, and the midpoint potential value Ic between potential values ​​Ia and Ib is calculated. Similarly, the midpoint potential value IIc is calculated from the potential value IIa that gives the oxidation current peak of ferrocene and the potential value IIb that gives the reduction current peak. The value of "the midpoint potential value Ic - the midpoint potential value IIc" is then taken as the potential of the ions involved in the charge-discharge reaction in the electrolyte (The electrode potential of Li (V vs. Fc / Fc+)).

[0054] The potential FVp of the ions involved in the charge-discharge reaction in the positive electrode electrolyte is usually -5.00V or higher and -1.00V or lower. From the viewpoint of further increasing the battery voltage, it is preferably -4.50V or higher and -1.50V or lower, more preferably -4.00V or higher and -1.50V or lower, even more preferably -3.50V or higher and -2.00V or lower, sufficiently preferably -3.30V or higher and -2.50V or lower, even more sufficiently preferably -3.20V or higher and -2.80V or lower, and particularly preferably -3.10V or higher and -2.85V or lower.

[0055] The potential FVn of the ions involved in the charge-discharge reaction in the negative electrode electrolyte is usually -6.00V or higher and -2.00V or lower. From the viewpoint of further increasing the battery voltage, it is preferably -5.00V or higher and -2.50V or lower, more preferably -4.50V or higher and -2.80V or lower, even more preferably -4.00V or higher and -3.00V or lower, sufficiently preferably -4.00V or higher and -3.30V or lower, even more certainly preferably -4.00V or higher and -3.50V or lower, and particularly preferably -3.90V or higher and -3.55V or lower.

[0056] The potential FVp of the ions involved in the charge-discharge reaction in the positive electrode electrolyte is usually higher than the potential FVn of the ions involved in the charge-discharge reaction in the negative electrode electrolyte. The difference (FVp - FVn) between the potential FVp of the ions involved in the charge-discharge reaction in the positive electrode electrolyte and the potential FVn of the ions involved in the charge-discharge reaction in the negative electrode electrolyte is not particularly limited, and from the viewpoint of further increasing the battery voltage, it is preferably 0.10 V or more and 2.00 V or less, more preferably 0.20 V or more and 1.50 V or less, still more preferably 0.35 V or more and 1.20 V or less, sufficiently preferably 0.55 V or more and 1.00 V or less, and even more sufficiently preferably 0.60 V or more and 0.95 V or less.

[0057] The electrolytes contained in the positive electrode electrolyte and the negative electrode electrolyte may each independently be metal salts of metals selected from the group consisting of alkali metals and alkaline earth metals. The metal constituting the electrolyte may be selected, for example, from the group consisting of lithium, sodium, potassium, calcium, and magnesium. From the viewpoint of further increasing the battery voltage, the metal is preferably lithium.

[0058] The electrolyte is not particularly limited as long as the electrolyte solution can contain the above metal in ionic form. For example, LiFSI (lithium bis(fluorosulfonyl)imide), LiTFSI (lithium bis(trifluoromethanesulfonyl)imide), LiClO ４ 、LiBF ４ 、LiPF ６ 、LiPOF ２ 、LiAsF ６ 、LiCF ３ SO ３ 、LiCF ３ CF ２ SO ３ 、LiC(CF ３ SO ２ ) ３ 、LiN(CF ３ SO ２ ) ２ 、LiN(CF ３ CF ２ SO ２ ) ２ 、LiN(CF ３ SO ２ )(C ４ F ９ SO２ ), LiN (CF ３ CF ２ CO) ２ Examples of lithium salts include LiFSI and LiPFA. The electrolyte is LiFSI, LiPFA, etc., from the viewpoint of further increasing the battery voltage. ６ It is preferable to select from the group consisting of LiTFSI. The electrolytes for the positive electrode electrolyte and the negative electrode electrolyte may be selected independently, but from the viewpoint of further increasing the battery voltage, it is preferable that the positive electrode electrolyte and the negative electrode electrolyte contain the same electrolyte. The same electrolyte means an electrolyte that can be represented by the same structural formula.

[0059] The solvents for the positive electrode electrolyte and the negative electrode electrolyte are non-aqueous solvents that dissolve the electrolyte, and examples include the solvent compounds shown in the donor number. The solvents for the positive electrode electrolyte and the negative electrode electrolyte are not particularly limited as long as the activity of the charge-discharge reaction participating ions in the positive electrode electrolyte and the negative electrode electrolyte (especially the molar ratio of charge-discharge contributing ions / solvent and the number of solvent donors in the positive electrode electrolyte and the negative electrode electrolyte) has the gradient described above, and may be selected independently.

[0060] The types of solvents for the positive electrode electrolyte and the negative electrode electrolyte are not particularly limited and may be independently selected from the group consisting of, for example, cyclic ureas, cyclic carbamates, cyclic amides, cyclic carbonates, cyclic esters, ethers, and phosphate esters.

[0061] Cyclic ureas are organic compounds represented by the following general formula (1).

[0062]

[0063] In formula (1), R １ and R ２ Each of these is independently a linear or branched alkyl group or phenyl group having 1 to 6 carbon atoms, and from the viewpoint of further increasing the battery voltage, it is preferably a linear or branched alkyl group or phenyl group having 1 to 3 carbon atoms, and more preferably a linear or branched alkyl group having 1 to 3 carbon atoms. １ and R ２These may be the same or different from one another. n is an integer between 2 and 4, and is preferably 2 or 3 from the viewpoint of further increasing the battery voltage.

[0064] Specific examples of cyclic ureas include, for example, 1,3-dimethylimidazolidinone, 1-ethyl-3-methylimidazolidinone, 1,3-diethylimidazolidinone, 1-propyl-3-methylpyrimidinone, 1,3-dimethylpropyleneurea (DMPU), 1-ethyl-3-propyleneurea, 1,3-diethylpropyleneurea, and 1-propyl-3-methylpropyleneurea. Among these, 1,3-dimethylimidazolidinone or 1,3-dimethylpropyleneurea are particularly preferred. The solvent may be the cyclic urea alone or mixed with other solvents.

[0065] Cyclic carbamates are organic compounds represented by the following general formula (2).

[0066]

[0067] In formula (2), R ３ R is a linear or branched alkyl group, allyl group, cyclohexyl group, or aryl or aralkyl group having 1 to 4 carbon atoms. ３ From the viewpoint of further increasing the battery voltage, it is preferably a linear or branched alkyl group or phenyl group having 1 to 4 carbon atoms, and more preferably a linear or branched alkyl group having 1 to 3 carbon atoms. ４ This is a linear or branched alkylene group having 2 to 8 carbon atoms, preferably 2 to 3 carbon atoms.

[0068] Specific examples of cyclic carbamates include, for example, 3-methyl-2-oxazolidone, 3-ethyl-2-oxazolidone, 3-vinyl-2-oxazolidone, and 3-allyl-2-oxazolidone, with 3-methyl-2-oxazolidone and 3-ethyl-2-oxazolidone being particularly preferred.

[0069] Cyclic amides are organic compounds represented by the following general formula (3).

[0070]

[0071] In formula (3), in the formula, R ５ R is a linear or branched alkyl group, allyl group, or cycloalkyl group, aryl group, or aralkyl group having 1 to 4 carbon atoms. ５ From the viewpoint of further increasing the battery voltage, it is preferably a linear or branched alkyl group having 1 to 4 carbon atoms, and more preferably a linear or branched alkyl group having 1 to 3 carbon atoms. ６ This is a linear or branched alkylene group having 2 to 8 carbon atoms, preferably 2 to 5 carbon atoms.

[0072] Specific examples of cyclic amides include, for example, 1-methyl-2-pyrrolidone (NMP), 1-ethyl-2-pyrrolidone, 1-vinyl-2-pyrrolidone, 1-allyl-2-pyrrolidone, 1-methyl-2-piperidone, 1-ethyl-2-piperidone, 1-methyl-2-caprolactam, and 1-ethyl-2-caprolactam. Particularly preferred cyclic amides include 1-methyl-2-pyrrolidone, 1-ethyl-2-pyrrolidone, 1-vinyl-2-pyrrolidone, 1-allyl-2-pyrrolidone, 1-methyl-2-caprolactam, and 1-ethyl-2-caprolactam.

[0073] Cyclic carbonates are organic compounds represented by the following general formula (4).

[0074]

[0075] In formula (4), in the formula, R ７ The alkylene group is a linear or branched alkylene group having 2 to 8 carbon atoms, and from the viewpoint of further increasing the battery voltage, it is preferably a linear or branched alkylene group having 2 to 4 carbon atoms. Some or all of the hydrogen atoms of the alkylene group may be substituted with halogen atoms (especially fluorine atoms).

[0076] Specific examples of cyclic carbonates include ethylene carbonate, propylene carbonate, and fluoroethylene carbonate. Particularly preferred cyclic carbonates include propylene carbonate and fluoroethylene carbonate.

[0077] Cyclic esters are organic compounds represented by the following general formula (5).

[0078]

[0079] In formula (5), in the formula, R ８ This is a linear or branched alkylene group having 2 to 8 carbon atoms, and from the viewpoint of further increasing the battery voltage, it is preferably a linear or branched alkylene group having 2 to 5 carbon atoms, more preferably 2 to 4 carbon atoms.

[0080] Specific examples of cyclic esters include, for example, 4-butyrolactone (GBL), delta-valerolactone, gamma-valerolactone, and epsilon-caprolactone. A particularly preferred cyclic ester is 4-butyrolactone (GBL).

[0081] The ethers include linear (or chain-like) ethers and cyclic ethers. From the viewpoint of further increasing the battery voltage, the ethers are preferably linear ethers.

[0082] Linear ethers are organic compounds represented by the following general formula (6). Cyclic ethers are heterocyclic compounds having one to three (particularly one or two) oxygen atoms as heteroatoms in one molecule, and are compounds with a 3-membered ring to an 8-membered ring (particularly a 5-membered or 6-membered ring). A cyclic ether is, for example, R in the following general formula (6). ９ and R １１ It is an organic compound formed by the formation of a ring, and for details, see R ９ Any one of the carbon atoms contained in and R １１ It may have a ring formed by a single bond connecting any one of the carbon atoms contained within it.

[0083]

[0084] In formula (6), in the formula, R９ and R １１ Each of these is independently a linear or branched alkyl group having 1 to 9 carbon atoms, a phenyl group, or a cyclohexyl group, and from the viewpoint of further increasing the battery voltage, it is preferably a linear or branched alkyl group having 1 to 3 carbon atoms or a phenyl group, and more preferably a linear or branched alkyl group having 1 to 3 carbon atoms. ９ and R １１ They may be the same as, or they may be different from, each other. １０ This is a linear or branched alkylene group having 2 to 8 carbon atoms, and from the viewpoint of further increasing the battery voltage, it is preferably a linear or branched alkylene group having 2 to 4 carbon atoms. n is 0 to 10 (particularly 1 to 10), and from the viewpoint of further increasing the battery voltage, it is preferably 1 to 5.

[0085] Examples of linear ethers include 1,2-dimethoxyethane, diethylene glycol diethyl ether (G2), triethylene glycol dimethyl ether (G3), tetraethylene glycol dimethyl ether (G4), diethylene glycol dibutyl ether, diethylene glycol methyl ethyl ether, triethylene glycol methyl ethyl ether, triethylene glycol butyl methyl ether, tetraethylene glycol dimethyl ether, and 1,2-crown-4 ether. Preferably, these are 1,2-dimethoxyethane and triethylene glycol dimethyl ether. Examples of cyclic ethers include tetrahydrofuran, 2-methyltetrahydrofuran, and 1,3-dioxolane-1,4-dioxane.

[0086] Phosphate esters are organic compounds represented by the following general formula (7).

[0087]

[0088] In formula (7), in the formula, R １２ , R １３ and R １４Each of these is independently a linear or branched alkyl group or phenyl group having 1 to 6 carbon atoms, and from the viewpoint of further increasing the battery voltage, it is preferably a linear or branched alkyl group or phenyl group having 1 to 3 carbon atoms, and more preferably a linear or branched alkyl group having 1 to 3 carbon atoms. １２ , R １３ and R １４ They may be the same as, or they may be different from, each other.

[0089] Specific examples of phosphate esters include triethyl phosphate (TEP) and trimethyl phosphate (TMP). A particularly preferred phosphate ester is triethyl phosphate (TEP).

[0090] The solvent of the positive electrode electrolyte preferably contains one or more compounds selected from the group consisting of cyclic carbonates, from the viewpoint of further increasing the battery voltage. In this case, the content of cyclic carbonate is usually 30 mol% or more (particularly 30 mol% or more and 100 mol% or less) relative to the total amount of solvent of the positive electrode electrolyte, preferably 50 mol% or more (particularly 50 mol% or more and 100 mol%), more preferably 70 mol% or more (particularly 70 mol% or more and 100 mol%), even more preferably 90 mol% or more (particularly 90 mol% or more and 100 mol%), and very preferably 95 mol% or more (particularly 95 mol% or more and 100 mol%), from the viewpoint of further increasing the battery voltage.

[0091] The solvent of the negative electrode electrolyte preferably contains one or more solvents selected from the group consisting of cyclic ureas, cyclic carbamates, cyclic amides, cyclic carbonates, cyclic esters, linear ethers, and phosphate esters (hereinafter sometimes simply referred to as "Group A"), more preferably contains one or more solvents selected from the group consisting of cyclic amides, cyclic carbonates, cyclic esters, linear ethers, and phosphate esters, even more preferably contains one or more solvents selected from the group consisting of cyclic amides, cyclic esters, linear ethers, and phosphate esters, and very preferably contains one or more solvents selected from the group consisting of cyclic amides and phosphate esters. In the solvent of the negative electrode electrolyte, the total content of solvents belonging to group A is usually 30 mol% or more (particularly 30 mol% to 100 mol%) relative to the total amount of solvent in the negative electrode electrolyte, preferably 50 mol% or more (particularly 50 mol% to 100 mol%), more preferably 70 mol% or more (particularly 70 mol% to 100 mol%), even more preferably 90 mol% or more (particularly 90 mol% to 100 mol%), and very preferably 95 mol% or more (particularly 95 mol% to 100 mol%).

[0092] From the viewpoint of further increasing the battery voltage, the following combinations of solvents for the positive electrode electrolyte and the negative electrode electrolyte are preferred: (i) cyclic carbonate-cyclic carbonate (especially PC-PC); (ii) cyclic carbonate-cyclic ester (especially PC-GBL); (iii) cyclic carbonate-linear ether (especially PC-DME); (iv) cyclic carbonate-cyclic amide (especially PC-NMP); (v) cyclic carbonate-phosphate ester (especially PC-TEP); PC: propylene carbonate GBL: 4-butyrolactone DME: 1,2-dimethoxyethane NMP: N-methylpyrrolidone TEP: triethyl phosphate

[0093] In the above combinations, the former and the latter represent the solvent for the positive electrode electrolyte and the solvent for the negative electrode electrolyte, respectively. From the viewpoint of further increasing the voltage, preferred combinations are combinations (ii) to (v), and more preferred combinations are combination (iv) or (v).

[0094] The positive electrode electrolyte and the negative electrode electrolyte may each independently contain additives other than the electrolyte and solvent. The additives are not particularly limited and may be any additives known as electrolyte additives in the field of batteries, such as non-aqueous secondary batteries. Examples of such additives include stabilizers.

[0095] Examples of stabilizers include dinitryl compounds. Dinitrile compounds are aliphatic hydrocarbon compounds having two nitrile groups (-CN), and may, for example, be composed of one alkylene group and two nitrile groups. Specific examples of dinitrile compounds include succinonitrile (number of C12 in the alkylene group = 2), glutalonitrile (number of C13 in the alkylene group = 3), adiponitrile (number of C14 in the alkylene group = 4), pimeronitrile (number of C15 in the alkylene group = 5), suberonitrile (number of C16 in the alkylene group = 6), azeranitrile (number of C17 in the alkylene group = 7), sebaconitrile (number of C18 in the alkylene group = 8), undecanedinitrile (number of C19 in the alkylene group = 9), and dodecaneditonyl (number of C10 in the alkylene group = 10).

[0096] The positive electrode electrolyte and the negative electrode electrolyte can each be prepared independently by adding and mixing an electrolyte and optionally an additive to a solvent, and then dissolving or dispersing them.

[0097] The electrolytes, such as the positive electrode electrolyte and the negative electrode electrolyte, may or may not be gel-like. If the electrolyte is not gel-like, it can be said to be non-gel-like. Gel-like means that when dynamic viscoelasticity measurements are performed on the electrolyte using a cone-shaped plate with a rheometer, the storage modulus G' is greater than or equal to the loss modulus G''. On the other hand, a state in which the storage modulus G' is less than the loss modulus G'' can be called non-gel-like (especially a sol (fluid) state). Only one of the positive electrode electrolyte or the negative electrode electrolyte may be gel-like. When at least one (preferably both) of the positive electrode electrolyte and the negative electrode electrolyte is gel-like, the fluidity of the electrolyte is eliminated, thus increasing the reliability of leak resistance.

[0098] When the positive electrode electrolyte and the negative electrode electrolyte are gel-like, each of the positive electrode electrolyte and the negative electrode electrolyte contains a gelling agent along with the electrolyte and solvent described above. Any polymer can be used as the gelling agent, as long as it does not impair the pressure-boosting effect of the battery of the present invention. Examples of such gelling agents include one or more polymers selected from the group consisting of polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, and polyacrylonitrile. These gelling agent polymers may further contain one or more monomer components selected from the group consisting of monomethyl maleate, trifluoroethylene, chlorotrifluoroethylene, acrylic acid, and methacrylic acid as copolymer components. Such gelling agents enable the gelation of the electrolyte without adversely affecting the coordination state of the charge-discharge reaction-participating ions (especially lithium ions) involved in the pressure-boosting effect and the state of the solvent (particularly the state relating to the activity and / or potential gradient of the charge-discharge reaction-participating ions in the positive electrode electrolyte and the negative electrode electrolyte). The gelling agent is preferably a vinylidene fluoride-hexafluoropropylene copolymer, from the viewpoint of further increasing the battery voltage and further increasing the energy density.

[0099] When the positive electrode electrolyte and the negative electrode electrolyte are gel-like, they maintain a gel state under battery operating conditions such as temperature, based on the physical or chemical crosslinking of the gelling agent polymer described above. In such cases, the positive electrode electrolyte and the negative electrode electrolyte can each be gelled independently by adding and mixing an electrolyte, gelling agent, and optionally additives to a solvent to obtain a coating solution, and then, as will be detailed later, by physically or chemically crosslinking the coating solution.

[0100] The gelling agent content in each of the gel-type positive electrode electrolyte and gel-type negative electrode electrolyte is usually 1% to 20% by weight of the total weight of the positive or negative electrode electrolyte, respectively, and is preferably 1% to 15% by weight, more preferably 1% to 10% by weight, from the viewpoint of further increasing the battery voltage, further increasing the energy density, and from the viewpoint of leak resistance reliability. "Total weight of the positive or negative electrode electrolyte" refers to "the total weight of the positive or negative electrode electrolyte in the finished product," and for example, it includes only solvents with a boiling point of 150°C or higher as the solvent. This is because solvents with a boiling point below 150°C will volatilize during the battery manufacturing process.

[0101] If the positive electrode electrolyte and the negative electrode electrolyte are gel-like, the positive electrode electrolyte and the negative electrode electrolyte may each independently further contain an alkali source compound. The alkali source compound promotes gelation.

[0102] Examples of alkali source compounds include lithium carbonate and LLZ-type solid electrolytes. Examples of LLZ-type solid electrolytes include Li ７ La ３ Zr ２ O １２ (and its powder) are examples.

[0103] The content of alkali source compounds (particularly lithium carbonate) in each of the gel-type positive electrode electrolyte and the gel-type negative electrode electrolyte is usually preferably 0.1% by weight or more and 5.0% by weight or less, and more preferably 0.3% by weight or more and 4.5% by weight or less, based on the total weight of the positive electrode electrolyte or the negative electrode electrolyte.

[0104] When the positive electrode electrolyte and the negative electrode electrolyte are gel-like, they can be obtained by independently adding and mixing an electrolyte, gelling agent, and optionally additives to a solvent to obtain a coating solution, which is then applied to the positive or negative electrode, and subsequently crosslinked physically or chemically. In this case, the coating solution may be diluted with a low-boiling point solvent to reduce its viscosity, so that it can easily penetrate into the electrode void. Such a low-boiling point solvent is usually removed by evaporation or other means after the coating solution has penetrated the electrodes, and may, for example, be a solvent with a boiling point of less than 150°C.

[0105] (Separator) Separator 4 is a microporous membrane with electrical insulating properties. Microporous means that it has a pore size that allows metal ions to pass through but not solvent molecules. Such pore sizes are usually 0.5 nm or more and less than 100 nm, and from the viewpoint of further increasing the battery voltage, it is preferably 1 nm or more and 80 nm or less, more preferably 1 nm or more and 50 nm or less, and even more preferably 1 nm or more and 10 nm or less. If a separator with a pore size that is too large is used, the battery voltage (or output voltage) cannot be increased sufficiently.

[0106] In this specification, pore diameters are those measured by the following method: The pore diameters of any 100 pores are measured from scanning electron microscope images, and the average value is calculated. The pore diameter may also be the maximum dimension.

[0107] The thickness of the separator is not particularly limited and may be, for example, 10 μm or more and 2 mm or less. From the viewpoint of further increasing the battery voltage, it is preferably 100 μm or more and 1.5 mm or less, and more preferably 500 μm or more and 1.2 mm or less.

[0108] The separator only needs to have the above-mentioned hole diameter in at least a portion of the thickness direction of the separator, but from the viewpoint of further increasing the voltage, it is preferable that the above-mentioned hole diameter is present throughout the entire thickness direction of the separator. The hole diameter is determined by using the average value of the diameter (maximum width) measured for any 100 holes in one surface portion of the separator, the other surface portion, and the central portion between them (a portion with a depth of thickness × 0.5). Having the above-mentioned hole diameter throughout the thickness direction of the separator means that all of the measured values ​​are within the range of their average value ± 5%.

[0109] The Guarley permeability of separator 4 is usually 500 seconds / 100 mL or more, preferably 1000 seconds / 100 mL or more, more preferably 1500 seconds / 100 mL or more, and even more preferably 1800 seconds / 100 mL or more, from the viewpoint of mitigating the mixing of the positive electrode electrolyte and the negative electrode electrolyte. The upper limit of the Guarley permeability of separator 4 is not particularly limited, and the Guarley permeability may usually be less than 8000 seconds / 100 mL, and particularly less than or equal to 5000 seconds / 100 mL.

[0110] In this specification, Gurley air permeability is defined as the time it takes for 100 mL of air to pass through the object being measured, and the value used is that measured by the Gurley method described in JIS-P8117 (Paper and cardboard - Air permeability test method). Specifically, for an area of ​​642 mm², ２ The time it takes for 100 mL of air to pass through the film (the object being measured) is measured by applying an inner cylinder pressure of 567 g.

[0111] The material of the separator is not particularly limited and may be composed of inorganic materials such as silica glass, borosilicate glass, alumina, or zirconia.

[0112] Separators are available commercially. For example, commercially available separators such as product name VF1-3 (silica glass, 1 mm thickness, 4 nm pore size, manufactured by EC Frontier Co., Ltd., Gurley permeability 2000 seconds / 100 mL) can be used.

[0113] (Positive electrode) The positive electrode 1 is configured with a positive electrode mixture layer on both or one side of the positive electrode current collector. The positive electrode mixture layer can be formed by applying a slurry containing a positive electrode active material, a conductive agent, and a binder to the positive electrode current collector and drying it.

[0114] The positive electrode active material is not particularly limited as long as it is capable of intercalating and deintercalating charge-discharge reaction-participating ions, and deintercalating and intercalating charge-discharge reaction-participating ions, and known electrode active material materials can be used. When the charge-discharge reaction-participating ions are lithium ions, lithium cobalt oxide (LiCoO) ２ ), lithium nickelate (LiNiO ２ ), lithium manganese spinel (LiMn ２ O ４ ), general formula: LiNi ｘ Co ｙ Mn ｚ O ２ (x+y+z=1) or Li ａ Ni ｘ Co ｙ Al １－ｘ－ｙ O ２ A composite metal oxide represented by (0.98 < a < 1.2, 0 < x, y < 1), olivine-type LiMPO ４ (wherein M represents Co, Ni, Mn, Fe, or V), lithium vanadium compounds (LiVOPO) ４ Examples include composite metal oxides such as ). The positive electrode active material is olivine-type LiMPO ４ Preferably, LiFePO ４ LiMn １－ｘ Fe ｘ PO ４ (It is preferable that x is a number greater than 0 and less than 1.)

[0115] The conductive agent in the positive electrode mixture layer is not particularly limited, and known conductive agents can be used. Examples include pyrolytic carbon such as carbon black, coke, glassy carbons, calcined organic polymer compounds, carbon fibers, or activated carbon. Among carbon blacks, acetylene black and Ketjen black are particularly preferred, with acetylene black being particularly preferred.

[0116] The binder for the positive electrode active material layer is not particularly limited as long as it can bind the particles of the positive electrode active material and the particles of the conductive agent. For example, fluororesins such as polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), tetrafluoroethylene - hexafluoropropylene copolymer (FEP), tetrafluoroethylene - perfluoroalkyl vinyl ether copolymer (PFA), ethylene - tetrafluoroethylene copolymer (ETFE), polychlorotrifluoroethylene (PCTFE), ethylene - chlorotrifluoroethylene copolymer (ECTFE), and polyvinyl fluoride (PVF) can be mentioned. The binder may contribute not only to the binding of the particles of the positive electrode active material and the particles of the conductive agent but also to the binding to the positive electrode current collector.

[0117] For the positive electrode current collector, various known metal foils used for current collectors in lithium - ion secondary batteries can be used. Specifically, it is preferable to use an aluminum foil.

[0118] (Negative electrode) The negative electrode 2 is configured to include a negative electrode active material layer on both sides or one side of the negative electrode current collector The negative electrode active material layer can be formed by applying a slurry containing a negative electrode active material, a conductive agent, and a binder to the negative electrode current collector and drying it.

[0119] The negative electrode active materials include carbon materials such as natural graphite, artificial graphite (hard - graphitized carbon, easy - graphitized carbon, low - temperature - fired carbon, etc.), and MCF (mesocarbon fiber); metals that can form compounds with alkali metals containing lithium such as Al, Si, Sn, etc., amorphous compounds mainly composed of oxides such as SiO ２ 、SnO ２ etc.; oxides such as lithium titanate (Li<� ４ Ti ５ O １２ ), niobium titanate (TiNb ２ O ７ ). From the perspective of further increasing the battery voltage, the negative electrode active material is preferably an oxide (particularly lithium titanate (Li ４ Ti ５ O １２ ).

[0120] The conductive agent and binder in the negative electrode mixture layer can be the same materials as those used in the positive electrode mixture layer. Therefore, the binder contained in the negative electrode mixture layer may contribute not only to the bonding of the negative electrode active material particles and the conductive agent particles, but also to the bonding to the negative electrode current collector.

[0121] The negative electrode current collector can be any known metal foil used in current collectors for lithium-ion secondary batteries. Specifically, aluminum foil or copper foil is preferred.

[0122] (Battery) In the battery of the present invention (particularly a secondary battery), the mixing of the positive electrode electrolyte 31 and the negative electrode electrolyte 32 is suppressed by the separation of a microporous membrane separator 4. Metal ions, which are ions involved in the charge-discharge reaction, permeate the separator 4 between the positive electrode electrolyte 31 and the negative electrode electrolyte 32 and are responsible for the transfer of charge.

[0123] (Outer casing) The outer casing is not particularly limited and may be, for example, a flexible pouch (soft bag) or a hard case (rigid housing).

[0124] When the outer packaging is a flexible pouch, the flexible pouch is usually formed from a laminate film, and sealing is achieved by heat-sealing the periphery. The laminate film is typically a film made by laminating a metal foil and a polymer film. Specifically, a three-layer structure consisting of an outer polymer film, metal foil, and an inner polymer film is exemplified. The outer polymer film prevents the permeation of moisture and damage to the metal foil due to contact, and polymers such as polyamide and polyester are suitably used. The metal foil prevents the permeation of moisture and gases, and foils such as copper, aluminum, and stainless steel are suitably used. The inner polymer film protects the metal foil from the electrolyte contained within and allows for melt sealing during heat sealing; polyolefin (e.g., polypropylene) or acid-modified polyolefin is suitably used. The thickness of the laminate film is not particularly limited and may be, for example, 1 μm or more and 1 mm or less.

[0125] When the outer casing is a hard case, the hard case is usually formed from a metal plate, and sealing is achieved by laser irradiation of the periphery. Common metal materials for the metal plate include aluminum, nickel, iron, copper, stainless steel, etc. The thickness of the metal plate is not particularly limited and may be, for example, 1 μm or more and 1 mm or less.

[0126] [Method for Manufacturing a Battery] The secondary battery of the present invention may be manufactured by any method. For example, if the positive electrode electrolyte and the negative electrode electrolyte are non-gel-like, it can be manufactured by a method including the following steps: A housing step in which the positive electrode 1, the negative electrode 2, and the separator 4 are housed in the outer casing through its opening; an injection step in which the positive electrode electrolyte 31 is injected into the positive electrode 1 side of the separator 4 within the outer casing while in contact with the positive electrode 1, and the negative electrode electrolyte 32 is injected into the negative electrode 2 side of the separator 4 while in contact with the negative electrode 2; a sealing step in which the opening is sealed after the inside of the outer casing has been degassed.

[0127] Prior to the housing process, the positive electrode 1, the negative electrode (not shown), and the separator 4 placed between the positive and negative electrodes may be pre-stacked to form a laminate, as shown in Figure 2. Figure 2 is a schematic view showing an example of a laminated structure of a battery according to one embodiment of the present invention. In Figure 2, 1A shows the positive electrode tab drawn out from the positive electrode 1, and 2A shows the negative electrode tab drawn out from the negative electrode (not shown).

[0128] In the sealing process, the sealing method is not particularly limited. For example, if the outer packaging is a flexible pouch, a heat sealing method may be used. Alternatively, if the outer packaging is a hard case, a laser irradiation method or a crimping method may be employed.

[0129] If the positive electrode electrolyte and the negative electrode electrolyte are gel-like, the secondary battery of the present invention can be manufactured in the same manner as described above, except that instead of injecting the positive electrode electrolyte and the negative electrode electrolyte after the housing step, the positive electrode electrolyte and the negative electrode electrolyte are applied to the positive electrode and the negative electrode, respectively, before the housing step and allowed to gel.

[0130] In detail, first, a coating solution is obtained by mixing a diluent, a predetermined electrolyte, and a gelling agent with a solvent. Next, as shown in Figure 3A, one side (back side) of the electrode sheet is protected with adhesive masking tape 70, and the coating solution 71 is applied to the other side (front side) of the electrode sheet using a dispenser D. After that, the electrolyte is made into a gel by evaporating the diluent. As shown in Figure 3B, a gel-containing electrode sheet 75 is obtained in which the gel-like electrolyte 72 covers one side of the electrode sheet, the electrode surface is coated, and the gel has penetrated (or impregnated) into the electrode layer. Next, a non-porous polyolefin film 80 without an adhesive layer or an easy-adhesion layer is attached to the gel-coated surface of the gel-containing electrode sheet as a masking film, the masking tape 70 on the back side is peeled off, and the coating solution 71 is applied in the same manner as above, as shown in Figure 3C. After that, the electrolyte is made into a gel by evaporating the diluent, in the same manner as above. As shown in Figure 3D, a gel-containing electrode sheet 1 (or 2) can be obtained in which a gel-like electrolyte 72 is coated on both sides of the electrode sheet and penetrates (or impregnates) into the electrode layer, serving as the positive electrode 1 (or negative electrode 2). Figures 3A to 3D are schematic cross-sectional views illustrating an example of a manufacturing method for obtaining the secondary battery of the present invention having gel-like positive and negative electrode electrolytes.

[0131] By volatilizing the aforementioned diluting solvent, physical or chemical crosslinking occurs, and gelation is achieved. Physical crosslinking may be achieved by any scientifically known physical crosslinking method, for example, by the formation of entanglement of polymer chains and / or microcrystal formation due to temperature changes or stretching, etc. Chemical crosslinking may be achieved by any scientifically known chemical crosslinking method, for example, if the polymer chain of the gelling agent has an ionic group, an ionic crosslinking point may be formed by adding an ion with the opposite sign to the sign of the ionic group, or a covalent crosslinking point may be formed by adding a crosslinking agent to the gelling agent polymer.

[0132] In Figures 3A to 3D (especially Figure 3D), the positive electrode 1 (or negative electrode 2) has a positive electrode mixture layer (or negative electrode mixture layer) and a gel-like positive electrode electrolyte (or gel-like negative electrode electrolyte) covering the surface of the positive electrode mixture layer (or negative electrode mixture layer) and penetrating into its interior on both sides of the current collector. The positive electrode (or negative electrode) is not limited to this structure; for example, it may have a positive electrode mixture layer (or negative electrode mixture layer) and a gel-like positive electrode electrolyte (or gel-like negative electrode electrolyte) covering the surface of the positive electrode mixture layer (or negative electrode mixture layer) and penetrating into its interior on only one side of the current collector. Thus, an electrode (or electrode sheet) having a positive electrode mixture layer (or negative electrode mixture layer) and a gel-like positive electrode electrolyte (or gel-like negative electrode electrolyte) on only one side of the current collector may be manufactured by the same method as shown in Figures 3A and 3B, except that the positive electrode mixture layer (or negative electrode mixture layer) is not placed on the protective surface of the electrode sheet by the masking tape 70.

[0133] After obtaining the positive electrode 1 and negative electrode 2 by performing the gelation treatment described above, the secondary battery of the present invention can be obtained by performing the housing step in the outer casing and the sealing step of the opening.

[0134] The secondary battery of the present invention may have any structure as long as it includes the separator, positive electrode electrolyte, and negative electrode electrolyte described above, and may have, for example, a stacked structure. A stacked structure may be, for example, a structure in which the positive electrode, negative electrode, and separator are stacked in a planar manner.

[0135] <1> A battery having a positive electrode, a negative electrode, an electrolyte, and a separator, wherein the separator is a microporous membrane, the electrolyte is a non-aqueous electrolyte composed of a positive electrode electrolyte in contact with the positive electrode and a negative electrode electrolyte in contact with the negative electrode, arranged on either side of the separator, each of the positive electrode electrolyte and the negative electrode electrolyte contains a metal salt of a metal selected from the group consisting of alkali metals and alkaline earth metals and a solvent for dissolving the metal salt, and the activity of charge-discharge reaction participating ions in the positive electrode electrolyte is greater than the activity of charge-discharge reaction participating ions in the negative electrode electrolyte. <2> The battery according to claim 1, wherein the potential FVp (V vs Fc / Fc+) of charge-discharge reaction participating ions in the positive electrode electrolyte is higher than the potential FVn (V vs Fc / Fc+) of charge-discharge reaction participating ions in the negative electrode electrolyte. <3> The battery according to claim 2, wherein the potential FVp of the charge-discharge reaction-involved ions in the positive electrode electrolyte is -5.00 (V vs Fc / Fc+) or more and -1.00 (V vs Fc / Fc+) or less, and the potential FVn of the charge-discharge reaction-involved ions in the negative electrode electrolyte is -6.00 (V vs Fc / Fc+) or more and -2.00 (V vs Fc / Fc+) or less. <4> The battery according to claim 2 or 3, wherein the difference (FVp - FVn) between the potential FVp of the charge-discharge reaction-involved ions in the positive electrode electrolyte and the potential FVn of the charge-discharge reaction-involved ions in the negative electrode electrolyte is 0.10 V or more and 2.00 V or less. <5> The battery according to any one of claims 1 to 4, wherein the molar ratio Cp of charge-discharge reaction-involved ions / solvent in the positive electrode electrolyte is higher than the molar ratio Cn of charge-discharge reaction-involved ions / solvent in the negative electrode electrolyte. <6> The battery according to any one of claims 1 to 5, wherein the molar ratio Cp of charge / discharge reaction-involved ions / solvent in the positive electrode electrolyte is 0.01 or more and 0.70 or less, and the molar ratio Cn of charge / discharge reaction-involved ions / solvent in the negative electrode electrolyte is 0.01 or more and 0.50 or less. <7> The battery according to any one of claims 1 to 6, wherein the difference (Cp - Cn) between the molar ratio Cp of charge / discharge reaction-involved ions / solvent in the positive electrode electrolyte and the molar ratio Cn of charge / discharge reaction-involved ions / solvent in the negative electrode is 0.10 or more and 0.69 or less.<8> The battery according to any one of claims 1 to 7, wherein the number of solvent donors Dn of the negative electrode electrolyte is higher than the number of solvent donors Dp of the positive electrode electrolyte. <9> The battery according to any one of claims 1 to 8, wherein the number of solvent donors Dp of the positive electrode electrolyte is 6.0 or more and 20.0 or less, and the number of solvent donors Dn of the negative electrode electrolyte is 8.0 or more and 40.0 or less. <10> The battery according to any one of claims 1 to 9, wherein the difference (Dn-Dp) between the number of solvent donors Dn of the negative electrode electrolyte and the number of solvent donors Dp of the positive electrode electrolyte is 0.1 or more and 20.0 or less. <11> The battery according to any one of claims 1 to 10, wherein the molar ratio Cp of charge / discharge reaction-involved ions / solvent in the positive electrode electrolyte is higher than the molar ratio Cn of charge / discharge reaction-involved ions / solvent in the negative electrode electrolyte, and the number of solvent donors Dn of the negative electrode electrolyte is higher than the number of solvent donors Dp of the positive electrode electrolyte. <12> The battery according to any one of claims 1 to 11, wherein the separator has a pore size of 0.5 nm or more and less than 100 nm. <13> The battery according to any one of claims 1 to 12, wherein the metal is selected from the group consisting of lithium, sodium, potassium, calcium, and magnesium. <14> The battery according to any one of claims 1 to 13, wherein the battery is a lithium-ion secondary battery. <15> The battery according to any one of claims 1 to 14, wherein the solvent is a non-aqueous solvent. <16> The battery according to any one of claims 1 to 15, wherein the solvent of the positive electrode electrolyte contains one or more compounds selected from the group consisting of cyclic carbonates, and the solvent of the negative electrode electrolyte contains one or more solvents selected from the group consisting of cyclic ureas, cyclic carbamates, cyclic amides, cyclic carbonates, cyclic esters, cyclic and linear ethers, and phosphate esters. <17> The battery according to any one of claims 1 to 16, wherein the positive electrode electrolyte and / or the negative electrode electrolyte is a gel electrolyte. <18> The battery according to any one of claims 1 to 17, wherein the positive electrode and the negative electrode are electrodes capable of intercalating and deintercalating lithium ions.

[0136] The present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited in any way to these examples.

[0137] <Experimental Example A (Investigation of secondary batteries having microporous membranes and non-gel electrolytes)> [Example 1] (Preparation of positive electrode electrolyte) In an Ar glove box at a temperature of 25°C, Li salt (LiFSI: lithium bis(fluorosulfonyl)imide) and solvent (PC: propylene carbonate) were dissolved in a molar ratio of 1:2 to obtain a positive electrode electrolyte.

[0138] (Preparation of negative electrode electrolyte) In an Ar glove box at a temperature of 25°C, the Li salt (LiFSI: lithium bis(fluorosulfonyl)imide) and solvent (PC: propylene carbonate) were dissolved in a molar ratio of 1:10.6 to obtain the negative electrode electrolyte.

[0139] (Measurement of the potential of ions involved in charge-discharge reactions in the positive electrode electrolyte) 18.63 g of ferrocene (molecular weight 186.03) was dissolved in 100 mL of positive electrode electrolyte to a concentration of 1 mmol / L. Cyclic voltammetry measurements were performed in an Ar glove box at 25°C with Pt as the working electrode, lithium metal as the counter electrode, and lithium metal as the reference electrode, at a sweep rate of 5 mV / sec. The potential value Ia, which gives the oxidation current peak corresponding to lithium dissolution, and the potential value Ib, which gives the reduction current peak corresponding to lithium ion electrodeposition, were used to calculate the midpoint potential value Ic between potential value Ia and potential value Ib. Similarly, the midpoint potential value IIc was calculated from the potential value IIa, which gives the oxidation current peak of ferrocene, and the potential value IIb, which gives the reduction current peak. Next, the value of "the aforementioned central potential value Ic - the aforementioned central potential value IIc" was defined as the potential of the ions involved in the charge-discharge reaction in the positive electrode electrolyte (The electrode potential of Li (V vs. Fc / Fc+)).

[0140] (Measurement of the potential of ions involved in charge-discharge reactions in the negative electrode electrolyte) The potential of ions involved in charge-discharge reactions in the negative electrode electrolyte (The electrode potential of Li (V vs. Fc / Fc+)) was obtained using the same method as for measuring the positive electrode potential in the positive electrode electrolyte, except that the negative electrode electrolyte was used instead of the positive electrode electrolyte.

[0141] (Manufacturing of the positive electrode) LiFePO4 as the positive electrode active material ４, acetylene black was used as the conductive agent and polyvinylidene fluoride was used as the binder, and they were mixed at a mass ratio of 80:12:8. This mixture was dispersed in N-methyl-2-pyrrolidone to prepare a positive electrode slurry. Next, this positive electrode slurry was coated on one side of an aluminum foil with a thickness of 15 μm, which is the positive electrode current collector. By drying and removing NMP by hot air heating and pressing, a positive electrode sheet with a positive electrode mixture layer formed on one side of the positive electrode current collector was obtained. In Example 1, the coating amount of LiFePO ４ was adjusted to be 10 mg / cm ２ .

[0142] (Manufacture of negative electrode) As the negative electrode active material, Li ４ Ti ５ O １２ , acetylene black as the conductive agent, and polyvinylidene fluoride as the binder were mixed at a mass ratio of 90:5:5. This mixture was dispersed in N-methyl-2-pyrrolidone to prepare a negative electrode slurry. Next, this negative electrode slurry was coated on one side of an aluminum foil with a thickness of 15 μm, which is the negative electrode current collector. By drying and removing NMP by hot air heating and pressing, a negative electrode sheet with a negative electrode mixture layer formed on one side of the negative electrode current collector was obtained. In Example 1, the coating amount of Li ４ Ti ５ O １２ was adjusted to be 14.3 mg / cm ２ .

[0143] (Manufacture of "Evaluation Battery A") Using the positive electrode sheet and negative electrode sheet manufactured above, the active material layer (mixture layer) was peeled off and the sheets were cut. As shown in FIG. 4, a positive electrode 1 and a negative electrode 2 having a rectangular active material layer 11, 21 with dimensions of 10 mm × 10 mm and only the portions of the current collectors (aluminum supports) 10, 20 where the active material layer was peeled off and exposed were manufactured. FIG. 4 shows schematic cross-sectional views and schematic plan views of the positive electrode and negative electrode manufactured in the example, respectively.

[0144] As shown in Figure 5, an "evaluation battery A" was manufactured in an Ar glove box using a positive electrode 1, a negative electrode 2, positive electrode electrolyte 31, and negative electrode electrolyte 32, with a microporous membrane (product name VF1-3, silica-containing glass, 15 mm x 15 mm rectangle, 1 mm thick, manufactured by EC Frontier, Gurley permeability 2000 sec / 100 mL) with a pore size of 4 nm as the separator 4. The positive electrode electrolyte 31 and negative electrode electrolyte 32 were sealed inside. Figure 5 shows a schematic cross-sectional view of the secondary battery manufactured in the example (particularly experimental example A). The separator had the above-mentioned pore size throughout its entire thickness.

[0145] (Evaluation of "Evaluation Battery A") First, a separate "Condition Setting Battery A" was manufactured, and the "SOC 30% charge" condition and the "0.1C current value" were determined using "Condition Setting Battery A". In detail, "Condition Setting Battery A" had the same structure as Figure 5, except that it did not use a microporous membrane separator and used a common electrolyte for both the positive and negative electrode electrolytes. More specifically, the positive electrode 1 and negative electrode 2 described above were used with a 1 mol / L LiPF4 solution with propylene carbonate as the solvent. ６ A "condition setting battery A" was manufactured by sealing in the electrolyte. This "condition setting battery A" was charged to 2.2V with a constant current and constant voltage, and the amount of charge was determined. The amount of charge obtained by multiplying this amount by 0.3 was defined as the "30% SOC charge." Furthermore, the current value that can charge the aforementioned amount of charge with a constant current in 10 hours was defined as the "0.1C current value."

[0146] Next, using "Evaluation Battery A," it was charged at a constant current and voltage of 0.1C current until it reached 3.0V, and then discharged at a constant current of 0.1C current until it reached 1.5V. This discharged amount was taken as the battery capacity. After standing for one hour, it was charged at a constant current of 0.1C current until it reached 30% of its state of charge (SOC). After standing for one hour, the open-circuit voltage was measured.

[0147] [Examples 2-8 and Comparative Examples 1-3] Except for the production of positive electrode electrolytes and negative electrode electrolytes having the compositions shown in Table 1, the potential of ions involved in the charge-discharge reaction in the positive electrode electrolytes and negative electrode electrolytes, as well as the production and evaluation of "Evaluation Battery A," were carried out in the same manner as in Example 1.

[0148] [Evaluation of Open-Circuit Voltage] The open-circuit voltage Vo was evaluated according to the following criteria: ◎: 2.6 ≤ Vo (best); ○: 2.3 ≤ Vo < 2.6 (good); △: 2.1 ≤ Vo < 2.3 (no practical problems); ×: Vo < 2.1 (practical problems).

[0149] <Experimental Example B (Investigation of a secondary battery having a microporous membrane and a gel-like electrolyte)> [Example 9] The potential of ions involved in the charge-discharge reaction in the positive electrode electrolyte and the negative electrode electrolyte was measured, and the "evaluation battery B" was manufactured and evaluated using the same method as in Example 4 of Experimental Example A, except that the positive electrode electrolyte and the negative electrode electrolyte were gel-like and the "evaluation battery" had the structure shown in Figure 6. Details are as follows.

[0150] (Manufacturing of gel-containing cathode sheet) A cathode sheet obtained by the same method as in Example 4 was used. A powder of propylene carbonate and vinylidene fluoride-hexafluoropropylene copolymer was dissolved at 40°C in a weight ratio of 20:1 in a dry air atmosphere with a dew point of -40°C. Next, lithium bis(fluorosulfonyl)imide was added so that the molar ratio of propylene carbonate to lithium bis(fluorosulfonyl)imide was 1:1.5. Next, dimethyl carbonate was added in a weight ratio of 1:2 with propylene carbonate. Next, Li with an average particle size of 1 μm was added as an alkali source. ７ La ３ Zr ２ O １２The powder was added to the propylene carbonate at a concentration of 1% by weight, stirred and mixed to obtain a coating solution. One side of the positive electrode sheet (the side without the positive electrode mixture layer) was protected with adhesive masking tape 70. The coating solution 71 was applied to the other side of the positive electrode sheet (the side with the positive electrode mixture layer) using dispenser D (Figure 3A), and dried and concentrated at 40°C, mainly by volatilizing dimethyl carbonate (Figure 3B). As a result, a gel-containing positive electrode sheet (gel-like positive electrode electrolyte-containing positive electrode sheet) 75 was obtained in which the gel-like electrolyte 72 coated the positive electrode surface on one side of the positive electrode sheet at 25°C and penetrated (or impregnated) into the positive electrode layer. The gelling agent content was 2.19% by weight of the total weight of the gel-like positive electrode electrolyte. The alkali source compound content was 0.438% by weight of the total weight of the gel-like positive electrode electrolyte.

[0151] (Manufacturing of Gel-Containing Anode Sheet) An anode sheet obtained by the same method as in Example 4 was used. In a dry air atmosphere with a dew point of -40°C, powders of N-methylpyrrolidone and vinylidene fluoride-hexafluoropropylene copolymer were dissolved at 40°C in a weight ratio of 20:1. Next, lithium bis(fluorosulfonyl)imide was added to the above so that the molar ratio of N-methylpyrrolidone was 10.5. Next, dimethyl carbonate was dissolved to the above N-methylpyrrolidone in a weight ratio of 1:2. Next, Li with an average particle size of 1 μm was used as an alkali source. ７ La ３ Zr ２ O １２The powder was added to N-methylpyrrolidone at a concentration of 2% by weight, stirred, and mixed to obtain a coating solution. One side of the negative electrode sheet (the side without the negative electrode mixture layer) was protected with adhesive masking tape 70. The coating solution 71 was applied to the other side of the negative electrode sheet (the side with the negative electrode mixture layer) using dispenser D (Figure 3A), and the dimethyl carbonate was evaporated at 40°C to dry and concentrate the solution (Figure 3B). As a result, a gel-containing negative electrode sheet (gel-like negative electrode electrolyte-containing negative electrode sheet) 75 was obtained in which the gel-like electrolyte 72 coated the negative electrode surface on one side of the negative electrode sheet at 25°C and penetrated (or impregnated) into the negative electrode layer. The gelling agent content was 4.0% by weight of the total weight of the negative electrode electrolyte. The alkali source compound content was 1.6% by weight of the total weight of the negative electrode electrolyte.

[0152] (Measurement of the potential of charge-discharge reaction-involved ions in gel-type positive electrode electrolyte) The potential of charge-discharge reaction-involved ions in the gel-type positive electrode electrolyte was measured using the same method as in the "Measurement of the potential of charge-discharge reaction-involved ions in positive electrode electrolyte" method of Experimental Example A described above, except that a gel-type positive electrode electrolyte was used. The gel-type positive electrode electrolyte was obtained by volatilizing dimethyl carbonate without applying the coating solution obtained in the "Manufacturing of gel-containing positive electrode sheet" method described above.

[0153] (Measurement of the potential of charge-discharge reaction-involved ions in gel-type negative electrode electrolyte) The potential of charge-discharge reaction-involved ions in the gel-type negative electrode electrolyte was measured using the same method as in the "Measurement of the potential of charge-discharge reaction-involved ions in negative electrode electrolyte" method of Experimental Example A described above, except that a gel-type negative electrode electrolyte was used. The gel-type negative electrode electrolyte was obtained by volatilizing dimethyl carbonate without applying the coating solution obtained in the "Manufacturing of gel-containing negative electrode sheet" method described above.

[0154] (Manufacturing of "Evaluation Battery B") A gel-containing positive electrode 75A and a gel-containing negative electrode 75B were obtained by the same method as the manufacturing method for the positive electrode and negative electrode in the manufacturing method of "Evaluation Battery A" in Experimental Example A, except that the gel-containing positive electrode sheet and gel-containing negative electrode sheet manufactured as described above were used. As shown in Figure 6, the gel-containing positive electrode 75A has a positive electrode mixture layer 11 and a gel-like positive electrode electrolyte 72A that covers the surface of the positive electrode mixture layer 11 and penetrates into its interior on a part of one side of the positive electrode current collector 10. As shown in Figure 6, the gel-containing negative electrode 75B has a negative electrode mixture layer 21 and a gel-like negative electrode electrolyte 72B that covers the surface of the negative electrode mixture layer 21 and penetrates into its interior on a part of one side of the negative electrode current collector 20.

[0155] As shown in Figure 6, an "evaluation battery B" was manufactured in an Ar glove box using a gel-containing positive electrode 75A and a gel-containing negative electrode 75B, with a microporous membrane (product name VF1-3, silica-containing glass, 15 mm x 15 mm rectangle, 1 mm thick, manufactured by EC Frontier, Gurley permeability 2000 sec / 100 mL) with a pore size of 4 nm as the separator 4. Figure 6 shows a schematic cross-sectional view of the secondary battery manufactured in the example (particularly experimental example B). The separator had the above-mentioned pore size throughout its entire thickness.

[0156] (Evaluation of "Evaluation Battery B") First, a "Condition Setting Battery B" was manufactured separately from "Evaluation Battery B," and the "SOC 30% charge" condition and the "0.1C current value" were determined using "Condition Setting Battery B." In detail, "Condition Setting Battery B" had the same structure as Evaluation Battery B (Figure 6), except that it did not use a microporous membrane separator and the gel-like positive electrode electrolyte was used in common on both the positive and negative electrode sides. More specifically, "Condition Setting Battery B" was manufactured using a gel-containing positive electrode and a gel-containing negative electrode manufactured by the same method as the manufacturing method for the gel-containing positive electrode and gel-containing negative electrode described above, except that they had a common composition as the gel-like positive electrode electrolyte and gel-like negative electrode electrolyte. This "Condition Setting Battery B" was charged to 2.2V with a constant current and constant voltage, and the amount of charge was determined. The amount of charge obtained by multiplying this amount of charge by 0.3 was defined as the "SOC 30% charge." Furthermore, the current value that allows the aforementioned amount of charge to be charged at a constant current in 10 hours was defined as the "0.1C current value."

[0157] Next, using "Evaluation Battery B," it was charged at a constant current and voltage of 0.1C current until it reached 3.0V, and then discharged at a constant current of 0.1C current until it reached 1.5V. This discharged amount was taken as the battery capacity. After standing for one hour, it was charged at a constant current of 0.1C current until it reached 30% of its state of charge (SOC). After standing for one hour, the open-circuit voltage was measured.

[0158] [Evaluation of Open-Circuit Voltage] The open-circuit voltage Vo was evaluated using the same method as in Experimental Example A.

[0159]

[0160] The battery according to the present invention can be used in various fields where voltage (or current) supply is anticipated. For example, the secondary battery according to the present invention can be used in various fields where battery use or energy storage is anticipated. Although this is merely an example, the secondary battery according to the present invention, in particular the non-aqueous electrolyte secondary battery, can be used in the field of electronics. The secondary battery according to the present invention, in particular the non-aqueous electrolyte secondary battery, can also be used in the electrical, information, and communication fields where mobile devices are used (e.g., the electrical and electronic equipment field or mobile device field, including small electronic devices such as mobile phones, smartphones, smartwatches, laptops, digital cameras, activity trackers, arm computers, electronic paper, wearable devices, RFID tags, card-type electronic money, and smartwatches), household and small industrial applications (e.g., power tools, golf carts, household, caregiving, and industrial robots), large industrial applications (e.g., forklifts, elevators, and port cranes), transportation systems (e.g., hybrid vehicles, electric vehicles, buses, trains, electric assist bicycles, electric motorcycles, etc.), power grid applications (e.g., various power generation systems, road conditioners, smart grids, and general household energy storage systems), medical applications (medical equipment fields such as earphones and hearing aids), pharmaceutical applications (medication management systems, etc.), and IoT fields, space and deep-sea applications (e.g., space probes, submersible research vessels, etc.).

Claims

1. A battery having a positive electrode, a negative electrode, an electrolyte, and a separator, wherein the separator is a microporous membrane, the electrolyte is a non-aqueous electrolyte composed of a positive electrode electrolyte in contact with the positive electrode and a negative electrode electrolyte in contact with the negative electrode, arranged on either side of the separator, each of the positive electrode electrolyte and the negative electrode electrolyte contains a metal salt of a metal selected from the group consisting of alkali metals and alkaline earth metals and a solvent for dissolving the metal salt, and the activity of charge-discharge reaction participating ions in the positive electrode electrolyte is greater than the activity of charge-discharge reaction participating ions in the negative electrode electrolyte.

2. The battery according to claim 1, wherein the potential FVp (V vs Fc / Fc+) of the charge-discharge reaction-participating ions in the positive electrode electrolyte is higher than the potential FVn (V vs Fc / Fc+) of the charge-discharge reaction-participating ions in the negative electrode electrolyte.

3. The battery according to claim 2, wherein the potential FVp of the charge-discharge reaction-participating ions in the positive electrode electrolyte is -5.00 (V vs Fc / Fc+) or more and -1.00 (V vs Fc / Fc+) or less, and the potential FVn of the charge-discharge reaction-participating ions in the negative electrode electrolyte is -6.00 (V vs Fc / Fc+) or more and -2.00 (V vs Fc / Fc+) or less.

4. The battery according to claim 2 or 3, wherein the difference (FVp - FVn) between the potential FVp of the charge-discharge reaction-involved ions in the positive electrode electrolyte and the potential FVn of the charge-discharge reaction-involved ions in the negative electrode electrolyte is 0.10 V or more and 2.00 V or less.

5. The battery according to any one of claims 1 to 4, wherein the molar ratio Cp of charge-discharge reaction-involved ions / solvent in the positive electrode electrolyte is higher than the molar ratio Cn of charge-discharge reaction-involved ions / solvent in the negative electrode electrolyte.

6. The battery according to any one of claims 1 to 5, wherein the molar ratio Cp of charge / discharge reaction-participating ions / solvent in the positive electrode electrolyte is 0.01 or more and 0.70 or less, and the molar ratio Cn of charge / discharge reaction-participating ions / solvent in the negative electrode electrolyte is 0.01 or more and 0.50 or less.

7. The battery according to any one of claims 1 to 6, wherein the difference (Cp - Cn) between the molar ratio of charge / discharge reaction-participating ions / solvent in the positive electrode electrolyte and the molar ratio of charge / discharge reaction-participating ions / solvent in the negative electrode is 0.10 or more and 0.69 or less.

8. The battery according to any one of claims 1 to 7, wherein the number of solvent donors Dn of the negative electrode electrolyte is higher than the number of solvent donors Dp of the positive electrode electrolyte.

9. The battery according to any one of claims 1 to 8, wherein the number of solvent donors Dp of the positive electrode electrolyte is 6.0 or more and 20.0 or less, and the number of solvent donors Dn of the negative electrode electrolyte is 8.0 or more and 40.0 or less.

10. The battery according to any one of claims 1 to 9, wherein the difference (Dn - Dp) between the number of solvent donors Dn of the negative electrode electrolyte and the number of solvent donors Dp of the positive electrode electrolyte is 0.1 or more and 20.0 or less.

11. The battery according to any one of claims 1 to 10, wherein the molar ratio Cp of charge / discharge reaction-involved ions / solvent in the positive electrode electrolyte is higher than the molar ratio Cn of charge / discharge reaction-involved ions / solvent in the negative electrode electrolyte, and the number of solvent donors Dn in the negative electrode electrolyte is higher than the number of solvent donors Dp in the positive electrode electrolyte.

12. The battery according to any one of claims 1 to 11, wherein the separator has a pore size of 0.5 nm or more and less than 100 nm.

13. The battery according to any one of claims 1 to 12, wherein the metal is selected from the group consisting of lithium, sodium, potassium, calcium, and magnesium.

14. The battery according to any one of claims 1 to 13, wherein the battery is a lithium-ion secondary battery.

15. The battery according to any one of claims 1 to 14, wherein the solvent is a non-aqueous solvent.

16. The battery according to any one of claims 1 to 15, wherein the solvent of the positive electrode electrolyte comprises one or more compounds selected from the group consisting of cyclic carbonates, and the solvent of the negative electrode electrolyte comprises one or more solvents selected from the group consisting of cyclic ureas, cyclic carbamates, cyclic amides, cyclic carbonates, cyclic esters, cyclic and linear ethers, and phosphate esters.

17. The battery according to any one of claims 1 to 16, wherein the positive electrode electrolyte and / or the negative electrode electrolyte is a gel electrolyte.

18. The battery according to any one of claims 1 to 17, wherein the positive electrode and the negative electrode are electrodes capable of intercalating and deintercalating lithium ions.

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