Separator, battery structure, and secondary battery

Abstract

Provided is a separator used for a secondary battery. The separator may comprises a complex-containing layer which is provided on a surface in contact with a negative electrode of the secondary battery and which contains an electrolyte complex. The electrolyte complex may contain a nitrate and a coordination substance. The nitrate may include at least one selected from lithium nitrate, potassium nitrate, cesium nitrate, sodium nitrate, silver nitrate, calcium nitrate, zinc nitrate, copper nitrate, magnesium nitrate, indium nitrate, aluminum nitrate, ammonium nitrate, barium nitrate, and iron nitrate.

Description

Separator, battery structure, and secondary battery

[0001] This invention relates to a separator, a battery structure, and a secondary battery.

[0002] Patent Document 1 discloses a secondary battery containing lithium nitrate powder and fluoroethylene carbonate (FEC) as an electrolyte. Patent Documents 2 and 3 disclose a secondary battery having a buffer layer containing lithium nitrate between the separator and the negative electrode. [Prior Art Documents] [Patent Documents] [Patent Document 1] Japanese Patent Application Publication No. 2023-55714 [Patent Document 2] Japanese Patent No. 7335022 [Patent Document 3] Japanese Patent Publication No. 2020-517056 General disclosure

[0003] (Means for solving the problem) In a first embodiment of the present invention, a separator for use in a secondary battery is provided. The separator is provided on the surface in contact with the negative electrode of the secondary battery and may include a complex-containing layer containing an electrolyte complex. The electrolyte complex may contain a nitrate and a coordination substance.

[0004] In the above separator, the electrolyte complex has a peak in the IR spectrum at 1350 cm⁻¹. －１ Above, 1395cm －１ It may be within the following range:

[0005] In any of the above separators, the electrolyte complex may have an ionic conductivity of 1E-7S / cm or more and 1E-3S / cm or less.

[0006] In any of the above separators, the electrolyte complex may have an ionic conductivity of 1E-5S / cm or more and 1E-3S / cm or less.

[0007] In any of the above separators, the amount of the coordination substance contained in the electrolyte complex may be 2% or more and 500% or less of the amount of the nitrate contained in the electrolyte complex.

[0008] In any of the above separators, the coordinating substance may contain one or more substructures selected from carbonyl groups, carboxyl groups, sulfinyl groups, sulfonyl groups, sulfides, ethers, esters, carbonate esters, amides, imides, phosphate esters, phosphine oxides, silyl groups, and borate esters.

[0009] In any of the above separators, the coordinating substance may include a structure obtained by radical polymerization of a monomer having a double bond or a triple bond.

[0010] In any of the above separators, the basis density of the electrolyte complex in the complex-containing layer is 0.01 g / cm³. ３ Above, 3.0g / cm ３ The following is acceptable:

[0011] In any of the above separators, the surface density of the electrolyte complex in the complex-containing layer is 0.01 mg / cm². ２ Above, 100mg / cm ２ The following is acceptable:

[0012] In any of the above-mentioned separators, the particle size of the electrolyte complex in the complex-containing layer may be 0.01 μm or more and 10 μm or less.

[0013] In any of the above-mentioned separators, the thickness of the complex-containing layer may be 0.01 μm or more and 20 μm or less.

[0014] In any of the above separators, the nitrate may include at least one selected from lithium nitrate, potassium nitrate, cesium nitrate, sodium nitrate, silver nitrate, calcium nitrate, zinc nitrate, copper nitrate, magnesium nitrate, indium nitrate, aluminum nitrate, ammonium nitrate, barium nitrate, and iron nitrate.

[0015] In any of the above separators, the coordinating substance may include at least one selected from fluoroethylene carbonate, vinylene carbonate, 1,2-dimethoxyethane, polyethylene oxide, carbonylmethylcellulose, polyimide, polyamide, polyimideamide, polysiloxane, and polycarbonate.

[0016] Any of the above separators may include a binder for supporting the electrolyte complex on the separator. The mass of the binder may be 0.5% or more and 30% or less of the mass of the electrolyte complex.

[0017] In any of the above separators, the binder may be at least one selected from polyvinylidene fluoride (PVDF), acrylic latex, acrylic resin, polyacrylic acid-styrene copolymer, styrene-butadiene rubber, polyvinyl alcohol, epoxy resin, sodium polyacrylate, polytetrafluoroethylene, polysiloxane, polyoxyethylene-methylpolysiloxane copolymer, polyimide, polyamide, polyamideimide, polyester, carboxymethylcellulose, cellulose derivatives, and polysulfone.

[0018] In any of the above-described separators, fibers for supporting the electrolyte complex on the separator may be included. The mass of the fibers may be 0.5% or more and 30% or less of the mass of the electrolyte complex.

[0019] In any of the above separators, the fiber may be at least one selected from hollow fibers, nanofibers, porous polymer fibers, and cellulose fibers.

[0020] A second embodiment of the present invention provides a battery structure comprising any of the above-described separators and a negative electrode in contact with the complex-containing layer.

[0021] In the above-described battery structure, the negative electrode may be selected from a lithium metal negative electrode, a graphite negative electrode, a silicon oxide negative electrode, and a silicon negative electrode.

[0022] A third aspect of the present invention provides a secondary battery comprising any of the above-described battery structures, a positive electrode disposed at a distance from the negative electrode, and a non-aqueous electrolyte.

[0023] The above-mentioned secondary battery may further contain the coordination substance in the non-aqueous electrolyte.

[0024] It should be noted that the above summary of the invention does not enumerate all of its features. Furthermore, subcombinations of these features may also constitute an invention.

[0025] A schematic diagram of the internal structure of the battery 100 is shown. A schematic diagram of the positive electrode 120 is shown. A schematic diagram of the negative electrode 140 is shown. A schematic diagram of the separator 130 is shown. A schematic diagram of the electrode structure 510 is shown. A schematic diagram of the manufacturing method of the battery 100 is shown.

[0026] The present invention will be described below through embodiments, but these embodiments are not intended to limit the scope of the claims. Furthermore, not all combinations of features described in the embodiments are necessarily essential to the solution of the invention.

[0027] In this specification, when a numerical range is expressed as "A to B", it means A or greater and B or less. Furthermore, "substituted or unsubstituted" means "substituted with any substituent, or not substituted with any substituent." The types of substituents are not particularly limited unless otherwise specified in the specification. Furthermore, the number of substituents is not particularly limited unless otherwise specified in the specification.

[0028] (Overview of the Battery 100) Figure 1 schematically shows an example of the internal structure of the battery 100. Figure 1 may be an example of a cross-sectional view of the battery 100. In this example, the details of the battery 100 will be explained using the case where the battery 100 is a rectangular secondary battery as an example.

[0029] In this example, the battery 100 stores electrical energy. The battery 100 also supplies the stored electrical energy to an external source. A power source can be created by connecting multiple batteries 100 in series and / or in parallel.

[0030] The type of storage battery 100 is not particularly limited, but the storage battery 100 may be an insertion-type storage battery or a reservoir-type storage battery. The storage battery 100 may also be a metal anode battery that uses a metal as the negative electrode active material. This makes it possible to obtain a storage battery 100 with a high energy density. Examples of metal anode batteries include alkali metal anode storage batteries, which are secondary batteries that use an alkali metal as the negative electrode material, and magnesium metal storage batteries, which are secondary batteries that use magnesium metal (sometimes called metallic magnesium) as the negative electrode material. An example of an alkali metal anode storage battery is a lithium metal storage battery, which is a secondary battery that uses lithium metal (sometimes called metallic lithium) as the negative electrode material.

[0031] The storage battery 100 may be a lithium-ion storage battery using an inorganic material as the negative electrode active material. The negative electrode active material may be artificial or natural graphite, silicon oxide (SiO2 ｘ ) or silicon (Si) may be included.

[0032] (Outline of parts of the storage battery 100) In this example, the storage battery 100 includes an electrode structure 110. In this example, the electrode structure 110 includes a positive electrode 120, a separator 130, and a negative electrode 140. As shown in Figure 1, in this example, the electrode structure 110 includes a laminate in which at least the negative electrode 140, the first separator 130, the positive electrode 120, and the second separator 130 are stacked in this order.

[0033] In this example, the details of the electrode structure 110 will be described using the case where one of the outermost layers of the electrode structure 110 is a positive electrode 120 and the other of the outermost layers of the electrode structure 110 is a negative electrode 140 as an example. However, the structure of the electrode structure 110 is not limited to this example. The electrode structure 110 may have various structures in which the positive electrode 120 and the negative electrode 140 are arranged opposite each other via a separator 130. For example, in a modified example, both of the outermost layers of the electrode structure 110 may be positive electrodes 120, or both of the outermost layers of the electrode structure 110 may be negative electrodes 140.

[0034] In this example, a positive electrode tab 122 is provided at the end of the positive electrode 120. In this example, a negative electrode tab 142 is provided at the end of the negative electrode 140. In this example, the storage battery 100 comprises a non-aqueous electrolyte 150, a battery case 160, a positive electrode terminal 162, a negative electrode terminal 164, a positive electrode lead 172, and a negative electrode lead 174.

[0035] In this example, the electrode structure 110 has a structure in which a positive electrode 120 and a negative electrode 140 are alternately stacked with a separator 130 in between. The separator 130 may be made up of a single sheet that has been folded, or it may be made up of multiple sheets.

[0036] In the storage battery 100 according to this example, the positive electrode 120 and the negative electrode 140 are arranged such that the positive electrode active material of the positive electrode 120 and the negative electrode active material of the negative electrode 140 face each other with a separator 130 in between. The negative electrode 140 has the function of directly exchanging charge in conjunction with the reaction of the positive electrode active material, for example. In contrast, depending on the type of battery, a third type of electrode may be provided in addition to the positive and negative electrodes.

[0037] For example, depending on the type of lithium-ion battery, a lithium electrode having lithium metal foil may be provided separately from the negative electrode. The lithium-ion battery described above includes, for example, an electrode stacking unit with a stacked structure of positive electrode / first separator / negative electrode / first separator / positive electrode / second separator / lithium electrode. In this case, the positive electrode and the lithium electrode are arranged so that the current collector of the positive electrode and the lithium metal foil of the lithium electrode face each other via the second separator. On the other hand, the positive electrode and the negative electrode are arranged so that the positive electrode active material of the positive electrode and the negative electrode active material of the negative electrode face each other with a separator in between. In this respect, the lithium electrode and the negative electrode can be distinguished.

[0038] (Positive electrode) The positive electrode 120 is positioned away from the negative electrode 140. In this example, the positive electrode 120 is electrically connected to the positive electrode terminal 162 via a positive electrode tab 122 and a positive electrode lead 172. In this example, the positive electrode tab 122 is positioned to protrude from the positive electrode 120. Details of the positive electrode 120 and the positive electrode tab 122 will be described later.

[0039] (Separator) In this example, the separator 130 is positioned between the positive electrode 120 and the negative electrode 140, separating them. This prevents the positive electrode 120 and the negative electrode 140 from directly contacting each other and causing a short circuit. The separator 130 ensures ionic conductivity between the positive electrode 120 and the negative electrode 140, for example, by holding the non-aqueous electrolyte 150.

[0040] In this example, the separator 130 includes a complex-containing layer 135 on the surface that contacts the negative electrode 140. Details of the complex-containing layer 135 will be described later. The separator 130 in this example may, together with the negative electrode 140, form a battery structure. That is, the storage battery 100 in this example may include a battery structure that includes the separator 130 and the negative electrode 140.

[0041] The separator 130 includes, for example, one or more polymer materials, one or more inorganic materials, and combinations thereof. Examples of materials for the separator 130 include cellulose, polyethylene terephthalate (PET), polyolefin, glass, and composites thereof. Examples of polyolefins include polyethylene, polypropylene, and ethylene-propylene copolymer.

[0042] Examples of the shape of the separator 130 include microporous films, nonwoven fabrics, and filters. The separator 130 may also be a laminate of these films or the like. The thickness of the separator 130 is not particularly limited, but is preferably 10 to 50 μm. The aperture ratio of the separator 130 is not particularly limited, but is preferably 30 to 70%.

[0043] The separator 130 may include multiple layers. At least two of the multiple layers may be layers with different materials, structures, and / or physical properties.

[0044] The separator 130 may include at least one layer of polyolefin film. The polyolefin film may be an unoriented film or an oriented film. The polyolefin film may be a porous oriented film. The oriented film may be a uniaxially oriented film or a biaxially oriented film.

[0045] The method for producing the porous polyolefin membrane that can be used as the separator 130 is not particularly limited. Examples of the method for producing the porous membrane include a dry method and a wet method. According to the dry method, first, the resin material is heated. As a result, the resin material melts. Next, the molten resin material is formed into a film. Next, after the heat treatment is applied to the formed film, the resin is stretched under specific conditions. Thereby, a film-like resin with pores formed therein is produced.

[0046] According to the wet method, first, a mixture of a resin material and a plasticizer is heated. As a result, the above mixture melts. Note that the above mixture may contain an inorganic filler. Next, the molten mixture is formed into a film. Next, the formed film is stretched under specific conditions. Thereafter, a process for extracting the plasticizer and a washing process are carried out. Thereby, a film-like resin with pores formed therein is produced.

[0047] (Complex-containing layer) The complex-containing layer 135 is a layer containing an electrolyte complex. The complex-containing layer 135 of this example is provided on the surface of the separator 130 that contacts the negative electrode 140. The complex-containing layer 135 may be provided on the surface that contacts the positive electrode 120. The complex-containing layer 135 may be formed by applying a slurry in which a metal salt, a metal oxide, a polymer compound, or the like is dispersed in an organic solvent to the separator 130.

[0048] (Electrolyte complex) The complex-containing layer 135 has particles of an electrolyte complex. The electrolyte complex contains at least a nitrate and a coordination substance. The particle diameter of the electrolyte complex may be measured by an electron microscope (SEM), a transmission electron microscope (TEM), an atomic force microscope (AFM), or the like. In this example, the particle diameter of the electrolyte complex in the complex-containing layer is 0.01 μm or more and 10 μm or less.

[0049] The basis weight density of the electrolyte complex in the complex-containing layer 135 of this example is 0.01 g / cm ３ or more and 3.00 g / cm ３The following applies. Here, the basis density of the electrolyte complex is the basis amount (g) of the electrolyte complex contained in the complex-containing layer 135 multiplied by the volume (cm³) of the complex-containing layer 135. ３ It is calculated by dividing by ). The basis weight (g) of the electrolyte complex is calculated as the change in weight of the separator 130 before and after coating the separator 130 with the electrolyte complex.

[0050] Volume of complex-containing layer 135 (cm³ ３ The basis density of the electrolyte complex may be calculated by multiplying the bottom area of ​​the complex-containing layer 135 by the thickness of the complex-containing layer 135. The bottom area of ​​the complex-containing layer 135 may be the cross-sectional area of ​​the separator 130. The basis density of the electrolyte complex is calculated by approximating the electrolyte complex as a sphere having the above particle size and the volume per electrolyte complex particle (cm³). ３ ) the density of the electrolyte complex (g / cm³) ３ ) and the number of electrolyte complex particles per unit volume of the complex-containing layer 135 ( / cm²) ３ You can calculate it by multiplying by ).

[0051] The surface density of the electrolyte complex in the complex-containing layer 135 of this example is (mg / cm²). ２ ) is 0.01 (mg / cm³) ２ ) or more, 100 (mg / cm ２ ) or less. The surface density of the electrolyte complex in the complex-containing layer 135 (mg / cm³) ２ ) is 0.1 (mg / cm³ ２ ) or more, and 0.2 (mg / cm³ ２ ) or more is acceptable. The surface density of the electrolyte complex in the complex-containing layer 135 (mg / cm³) ２ ) is 20 (mg / cm³ ２ ) may be less than or equal to 10 (mg / cm³). ２ The surface density of the electrolyte complex (mg / cm³) may be less than or equal to the following. ２ ) is the weight (mg) of the electrolyte complex contained in the complex-containing layer 135, and the bottom area (cm²) of the complex-containing layer 135. ２ You can calculate it by dividing by ).

[0052] The nitrate contained in the electrolyte complex may be the nitrate of the carrier metal of the battery 100. The nitrate may be an alkali metal nitrate or an alkaline earth metal nitrate. The nitrate may be at least one selected from lithium nitrate, potassium nitrate, cesium nitrate, sodium nitrate, silver nitrate, calcium nitrate, zinc nitrate, copper nitrate, magnesium nitrate, and indium nitrate.

[0053] The coordinating substance contained in the electrolyte complex is a low-molecular-weight or high-molecular-weight compound capable of forming a coordinate bond with the nitrate. The coordinating substance may include one or more substructures selected from carbonyl groups, carboxyl groups, sulfinyl groups, sulfonyl groups, sulfides, ethers, esters, carbonate esters, amides, imides, phosphate esters, phosphine oxides, silyl groups, and borate esters, which are capable of forming a coordinate bond with the nitrate. As an example, the coordinating substance is at least one selected from fluoroethylene carbonate (FEC), vinylene carbonate (VC), 1,2-dimethoxyethane (DME), polyethylene oxide (PEO), carbonylmethylcellulose (CMC), polyimide, polyamide, polyimidoamide, polysiloxane, and polycarbonate.

[0054] The coordinating substance may include structures obtained by radical polymerization of monomers having double or triple bonds. The coordinating substance may be at least one selected from polyvinyl alcohol (PVA), polyvinyl acetate (PVAc), polyacrylic acid (PAA), polymethyl methacrylate (PMMA), ethylene-vinyl acetate copolymer (EVA), styrene-acrylonitrile copolymer (SAN), Nafion, polyacetylene, polyphosphate ester, polyvinylboric acid, and polyacrylamide.

[0055] The electrolyte complex contains a coordinating substance in an amount that can form a coordinate bond with the nitrate. The amount of coordinating substance contained in the electrolyte complex may be the same as the amount of nitrate contained in the electrolyte complex, or it may be more or less than the amount of nitrate. In this example, the amount of coordinating substance contained in the electrolyte complex is 2% or more and 500% or less of the amount of nitrate contained in the electrolyte complex.

[0056] Electrolyte complexes are formed when a coordinating substance coordinates to a nitrate. The presence or absence of complex formation can be determined, for example, by IR spectroscopy or X-ray crystal structure analysis. The presence or absence of complex formation can be determined by the shift in the IR spectrum peak originating from the nitro group of the nitrate. Typically, the IR spectrum peak originating from the nitro group of the nitrate is at 1400 cm⁻¹. －１ Although observed in the vicinity, the electrolyte complex in this example exhibits a peak shift due to complex formation, causing the peak in the IR spectrum to shift to 1350 cm⁻¹. －１ Above, 1395cm －１ It has the following range:

[0057] The electrolyte complex exhibits improved ionic conductivity compared to the nitrate alone. This is due to the decrease in the crystal lattice energy of the nitrate upon complex formation, and the improvement in interparticle contactability and reduction of grain boundary resistance due to the introduction of a coordinating substance. The electrolyte complex in this example has an ionic conductivity of 1E-7 S / cm or higher and 1E-3 S / cm or lower. The electrolyte complex may also have an ionic conductivity of 1E-5 S / cm or higher and 1E-3 S / cm or lower.

[0058] The electrolyte complex has lower solubility in the non-aqueous electrolyte 150 compared to nitrate alone. As a result, the rate of ion release from the complex-containing layer 135 to the non-aqueous electrolyte 150 decreases during charging and discharging of the battery 100, so that the amount of ions at the interface between the negative electrode 140 and the separator 130 is maintained and the interfacial resistance does not increase.

[0059] The electrolyte complex includes a binder for supporting the electrolyte complex on the separator 130. The mass of the binder contained in the electrolyte complex may be 0.5% or more and 30% or less of the mass of the electrolyte complex. By including the binder in the electrolyte complex, the binder functions as a buffer layer, and a flexible electrolytic film can be formed that follows the volume change of the negative electrode 140.

[0060] The binder only needs to be chemically stable in the storage battery 100, and its type is not particularly limited. A thermoplastic resin or a thermosetting resin may be used as the binder. The binder may be at least one selected from polyvinylidene fluoride (PVDF), acrylic latex acrylic resin, polyacrylic acid-styrene copolymer, styrene-butadiene rubber, polyvinyl alcohol, epoxy resin, sodium polyacrylate, polytetrafluoroethylene, polysiloxane, polyoxyethylene-methylpolysiloxane copolymer, polyimide, polyamide, polyamideimide, polyester, carboxymethylcellulose, cellulose derivatives, and polysulfone.

[0061] The complex-containing layer 135 contains fibers for supporting the electrolyte complex on the separator 130. The mass of the fibers contained in the complex-containing layer 135 may be 0.5% or more and 30% or less of the mass of the supported electrolyte complex.

[0062] The fibrous layer has multiple fibers or bundles of fibers (these may be referred to as filaments). Multiple filaments form one or more voids extending into the interior of the fibers. The fibers may be at least one selected from hollow fibers, nanofibers, porous polymer fibers, and cellulose fibers. The fibers may be natural fibers, synthetic fibers, glass fibers, metal fibers, ceramic fibers, pulp, carbon fibers, etc.

[0063] (Negative electrode) In this example, the negative electrode 140 is electrically connected to the negative electrode terminal 164 via the negative electrode tab 142 and the negative electrode lead 174. In this example, the negative electrode tab 142 is positioned to protrude from the negative electrode 140.

[0064] If the storage battery 100 is a lithium metal battery using lithium metal as the negative electrode active material, lithium metal may dissolve and leach from the negative electrode 140. If the storage battery 100 is a lithium metal battery using lithium metal as the negative electrode active material, the electrode potential of the negative electrode 140 with respect to Li / Li+ may be 0.5V or less. The above electrode potential may be 0.2V or less, and preferably 0.1V or less. Details of the negative electrode 140 and the negative electrode tab 142 will be described later.

[0065] (Non-aqueous electrolyte) The non-aqueous electrolyte 150 forms an electrolytic film on the negative electrode 140 when the storage battery 100 is charged. The non-aqueous electrolyte 150 enables ion conduction between the positive electrode active material and the negative electrode active material through the electrolyte contained in the non-aqueous electrolyte 150. A known organic electrolyte may be used as the non-aqueous electrolyte 150. The non-aqueous electrolyte 150 includes, for example, a metal salt as an electrolyte and a polar solvent. The non-aqueous electrolyte 150 may further contain a coordination substance contained in the electrolyte complex of the complex-containing layer 135. The polar solvent may be an organic solvent.

[0066] The metal salt contained in the non-aqueous electrolyte 150 may be a salt of the carrier metal of the storage battery 100. The carrier metal may be an alkali metal. Examples of metal salts include lithium salt, sodium salt, potassium salt, cesium salt, magnesium salt, calcium salt, aluminum salt, zinc salt, silver salt, indium salt, ammonium salt, barium salt, and iron salt. A single type of metal salt may be used, or a combination of multiple types of metal salts may be used.

[0067] The metal salt may include alkali metal salts or alkaline earth metal salts. The metal salt may include alkali metal or alkaline earth metal nitrates. The metal salt may be one or more selected from nitrates such as lithium nitrate, sodium nitrate, potassium nitrate, cesium nitrate, magnesium nitrate, calcium nitrate, aluminum nitrate, zinc nitrate, silver nitrate, lead nitrate, indium nitrate or copper nitrate, at least one alkali metal salt selected from the group consisting of alkali metal fluoride salts, chloride salts, bromide salts, iodide salts, nitrates, nitrites, borates, fluoroborates, phosphates, fluorophosphates, sulfates or fluorosulfates, and at least one alkaline earth metal salt selected from the group consisting of alkaline earth metal fluoride salts, chloride salts, bromide salts, iodide salts, nitrates, nitrites, borates, fluoroborates, phosphates, fluorophosphates, sulfates or fluorosulfates.

[0068] The organic solvent contained in the non-aqueous electrolyte 150 is not limited in type, as long as it dissolves the metal salts mentioned above and is unlikely to cause side reactions such as decomposition within the voltage range used as a battery. A single type of organic solvent may be used as the organic solvent, or a combination of multiple organic solvents may be used.

[0069] The organic solvent is an ether-based or ester-based solvent that can be solvated with the metal salt described above. The organic solvent may be at least one selected from ethylene carbonate (EC), fluoroethylene carbonate (FEC), and dimethyl carbonate (DMC).

[0070] The electrolyte contained in the non-aqueous electrolyte 150 acts as a transport medium for ions involved in electrochemical reactions within the secondary battery. The electrolyte is lithium hexafluoride phosphate (LiPF). ６ ), lithium bis(fluorosulfonyl)imide (LiFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), LiBF ４ LiClO ４ LiC (CF ３ SO ２ ) ３ LiCH (CF ３ SO ２ ) ２ , LiF, LiCl, LiBr, LiI, or Li ２ It includes at least one selected from S. The electrolyte is LiB １２ F １２ LiAsF ６ LiFSO ３ Li ２ SiF ６ LiCF ３ CO ２ LiCH ３ CO ２ LiCF ３ SO ３ LiC ４ F ９ SO ３ LiCF ３ CF ２ SO ３ LiCF ３ (CF ２ )７ SO ３ 、LiCF ３ CF ２ (CF) ３ ) ２ Carbon, Li (CF) ３ SO ２ ) ２ H、LinO ３ 、LiN(CN) ２ 、Lii}(FSO) ２ ) ２ 、Lii}(F ２ SO ２ ) ２ 、Lii}(FF ３ SO ２ ) ２ 、LiN(C ２ F ５ SO ２ ) ２ 、Li+P(CF ３ ) ６ 、Li+PF(FF ３ ) ５ 、Li)PF ２ (CF) ３ ) ４ 、Li)PF ３ (CF) ３ ) ３ 、Li)PF ４ (CF) ３ ) ２ 、Li)PF ４ (C ２ F ５ ) ２ 、Li)PF ４ (CF) ３ SO ２ ) ２ 、Li)PF ４ (C ２ F ５ SO ２ ) ２ 、Liida ２ C ２ O ４ 、LiBC ４ O ８ 、Liida ２ (CF) ３ ) ２ 、Liida ２ (C ２ F ５ ) ２ 、Liida ２ (CF)３ SO ２ ) ２ LiBF ２ (C ２ F ５ SO ２ ) ２ LiSbF ６ LiAlO ４ LiAlF ４ , LiSCN or LiAlCl ４ This may include things like the following.

[0071] The non-aqueous electrolyte 150 may contain additional additives. Examples of additives include hydrofluoroethers (HFE). Hydrofluoroethers include 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE), 1H,1H,5H-octafluoropentyl-1,1,2,2-tetrafluoroethyl ether (OTE), 3,3,4,4-tetrafluorotetrahydrofuran (FTHF), 1,1,1,2,2,3,4,5,5,5-decafluoro-3-methoxy-4-(trifluoromethyl)pentane (HFE-7300), hexafluoroisopropyl methyl ether, and methyl nonafluorobutyl It may contain at least one selected from ether, methyl 2,2,3,3,3-pentafluoropropyl ether, 1,1,2,3,3,3-hexafluoropropyl methyl ether, 1,1,2,3,3,3-hexafluoropropyl ethyl ether, 1,1,2,2-tetrafluoroethyl 2,2,2-trifluoroethyl ether, bis(2,2,2-trifluoroethyl) ether, methyl 1,1,2,2-tetrafluoroethyl ether, or ethyl 1,1,2,2-tetrafluoroethyl ether.

[0072] (Housing) The battery case 160 houses the electrode structure 110 and the non-aqueous electrolyte 150. The electrode structure 110 and the non-aqueous electrolyte 150 may be sealed.

[0073] (An example of another embodiment) In this example, an example of a storage battery 100 has been described using the case where the storage battery 100 is a rectangular battery. However, the storage battery 100 is not limited to this example. In the modified example, the storage battery 100 may be a cylindrical battery, a laminated battery (sometimes called a pouch battery), or a coin cell battery.

[0074] In this example, an example of an electrode structure 110 was described, in which the electrode structure 110 has a laminated structure in which the positive electrode and negative electrode are alternately stacked with a separator in between. However, the electrode structure 110 is not limited to this example. In a modified example, the electrode structure 110 may have a wound type (sometimes referred to as a jelly roll type) in which the positive electrode, separator and negative electrode are stacked and wound into a roll.

[0075] (Electrochemical performance of the battery 100) The electrochemical performance of the battery 100 is influenced by the chemical reactions on the negative electrode 140 during charging and discharging of the battery 100. Specifically, it is desirable that an electrolytic film with good ion carrier conductivity and electrical conductivity be formed on the negative electrode 140 during charging and discharging of the battery 100.

[0076] Patent Document 2, listed in the prior art documents, discloses the placement of a buffering functional layer containing a polymer electrolyte having a polyethylene oxide (PEO) main chain and containing lithium nitrate between the separator and the negative electrode. Furthermore, Patent Document 3, also listed in the prior art documents, discloses the placement of a highly elastic polymer made of PEO and containing lithium nitrate between the separator and the negative electrode. The present inventors conducted further tests on the disclosures in Patent Documents 2 and 3, and confirmed that the introduction of PEO increased resistance at the negative electrode interface, resulting in a problem of reduced charge-discharge cycle life of the battery.

[0077] The inventors have found that by placing an electrolyte complex containing a carrier metal nitrate and a coordinating substance that forms a coordination bond with the nitrate at the interface between the negative electrode 140 and the separator 130, the charge-discharge cycle life of the storage battery can be improved. In particular, they have found that even when a binder such as PEO is introduced, the increase in the interfacial resistance of the negative electrode 140 can be suppressed due to the sustained release properties described later, thereby improving the cycle life of the storage battery 100.

[0078] Since the electrolyte complex has lower solubility in non-aqueous electrolytes compared to nitrate alone, its release rate into the non-aqueous electrolyte during the charge-discharge process is slower than that of nitrate alone. As a result, the electrolyte complex has the property of being released into the electrolyte more gradually than nitrate alone, i.e., it has sustained-release properties. In this way, the sustained-release properties of the electrolyte complex suppress the rapid change in the concentration of carrier metal ions at the interface of the negative electrode 140 during the charge-discharge process, and as a result, the resistance value at the interface of the negative electrode 140 can be kept constant.

[0079] Furthermore, Patent Document 1, listed in the prior art documents, discloses a configuration in which powdered lithium nitrate and fluoroethylene carbonate (FEC) are contained in the electrolyte. In this case, it is possible that FEC forms a coordination bond with lithium nitrate in the electrolyte, and a complex is formed. However, in the configuration of Patent Document 1, even if a complex is formed in the electrolyte, most of it is dispersed in the electrolyte and does not exist near the interface of the negative electrode 140. Therefore, the effect of placing the electrolyte complex at the interface between the negative electrode 140 and the separator 130, as in this example, cannot be obtained.

[0080] (Positive electrode) Figure 2 schematically shows an example of a positive electrode 120. In this example, the positive electrode 120 comprises a positive electrode current collector 220 and a positive electrode active material layer 240. The positive electrode 120 may comprise a laminate in which the positive electrode current collector 220 and the positive electrode active material layer 240 are stacked in this order. In this example, the positive electrode current collector 220 has a first main surface 222, a second main surface 224, and a side surface 226 connecting the first main surface 222 and the second main surface 224.

[0081] In this example, for the purpose of simplifying the explanation, the details of the positive electrode 120 will be described using the example where the positive electrode active material layer 240 is arranged on one side of the positive electrode current collector 220. However, the positive electrode 120 is not limited to this example. In a modified example, the positive electrode active material layer 240 may be arranged on both sides of the positive electrode current collector 220.

[0082] In this example, one end of the positive electrode current collector 220 has a region where the positive electrode active material layer 240 is not formed. This region is used as the positive electrode tab 122. In a modified example, a conductive terminal member may be provided on at least a part of the positive electrode tab 122. The material of the terminal member is not particularly limited, but examples include nickel, iron, copper, and aluminum.

[0083] In this example, the positive electrode current collector 220 holds the positive electrode active material layer 240. The material of the positive electrode current collector 220 can be any chemically stable electron conductor in the storage battery 100, and its type is not particularly limited. Examples of materials for the positive electrode current collector 220 include nickel, copper, iron, aluminum, stainless steel, nickel, titanium, or alloys thereof. Examples of shapes for the positive electrode current collector 220 include foil, mesh, punched metal, expanded metal, etc. The thickness of the positive electrode current collector 220 is not particularly limited, but is preferably 5 to 200 μm. The thickness of the positive electrode current collector 220 may be 6 to 20 μm.

[0084] In this example, the positive electrode active material layer 240 is formed on at least one surface of the positive electrode current collector 220. The thickness of the positive electrode active material layer 240 may be 1 to 300 μm or 2 to 200 μm per side of the positive electrode current collector 220. The positive electrode active material layer 240 includes, for example, a positive electrode active material and a binder. The positive electrode active material layer 240 may also contain a conductive additive.

[0085] In one embodiment, the positive electrode active material layer 240 is formed by applying a paste containing the materials constituting the positive electrode active material layer 240 and an organic solvent to at least one surface of the positive electrode current collector 220, and then drying the paste. The type of organic solvent is not particularly limited, but examples of such organic solvents include N-methylpyrrolidone (NMP). In a modified example, the positive electrode active material layer 240 is formed by mixing the materials constituting the positive electrode active material layer 240, molding them into a sheet, and then pressing the sheet-like mixture onto at least one surface of the positive electrode current collector 220.

[0086] As the positive electrode active material, for example, a material that can insert and remove metal ions that act as charge carriers and has a higher potential than the negative electrode active material is used. For example, if the storage battery 100 is a lithium battery, insertion-type transition metal oxides such as lithium layered oxide systems, olivine systems, and spinel systems are used as the positive electrode active material. Examples of lithium batteries include lithium-ion batteries and lithium metal batteries.

[0087] A high-capacity conversion-type positive electrode active material may be used as the positive electrode active material. Examples of high-capacity conversion-type positive electrode active materials include sulfur, sulfur compounds, iron fluoride, and transition metal oxides. Conversion-type positive electrode active materials do not contain metals that act as charge carriers in their initial state. Therefore, when a positive electrode containing a conversion-type positive electrode active material is combined with a metal negative electrode, the energy density of the battery 100 is greatly improved.

[0088] In this example, the binder binds the materials constituting the positive electrode active material layer 240 (e.g., positive electrode active material, conductive additive, etc.) and maintains the electrode shape of the positive electrode 120. The binder only needs to be chemically stable in the storage battery 100, and its type is not particularly limited. A thermoplastic resin or a thermosetting resin may be used as the binder. Examples of binders include polyethylene, polypropylene, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyacrylic acid, and styrene-butadiene rubber.

[0089] In this example, the conductive additive reduces the resistance of the positive electrode 120. The conductive additive can be any material that is chemically stable in the battery 100 and has the desired electronic conductivity, and its type is not particularly limited. Inorganic materials or organic materials may be used as the conductive additive. Carbon materials are examples of conductive additives. Examples of carbon materials include graphite, carbon black (e.g., acetylene black, Ketjenblack, etc.), coke, amorphous carbon, carbon fibers, carbon nanotubes, and graphene. These conductive additives may be used alone or in combination of two or more types.

[0090] (Negative Electrode) In the embodiment shown in Figure 3, the negative electrode 140 comprises, for example, a negative electrode current collector 320 and a negative electrode active material layer 340. The negative electrode 140 may comprise a laminate in which the negative electrode current collector 320 and the negative electrode active material layer 340 are stacked in this order. This separates the positive electrode active material layer 240 of the positive electrode 120 and the negative electrode active material layer 340 of the negative electrode 140 by at least a separator 130. As a result, an electrode structure 110 with excellent short-circuit resistance, chemical stability, and / or physical stability is obtained. The negative electrode 140 may have other layers between the negative electrode current collector 320 and the negative electrode active material layer 340.

[0091] In this example, for the purpose of simplifying the explanation, the details of the negative electrode 140 will be described using the example where the negative electrode active material layer 340 is arranged on one side of the negative electrode current collector 320. However, the negative electrode 140 is not limited to this example. In a modified example, the negative electrode active material layer 340 may be arranged on both sides of the negative electrode current collector 320. In this case, the negative electrode 140 is formed by stacking, for example, the negative electrode active material layer 340, the negative electrode current collector 320, and the negative electrode active material layer 340 in that order.

[0092] In this example, the negative electrode current collector 320 has a first main surface 322, a second main surface 324, and a side surface 326 connecting the first main surface 322 and the second main surface 324. In this example, the negative electrode active material layer 340 has a first main surface 342, a second main surface 344, and a side surface 346 connecting the first main surface 342 and the second main surface 344.

[0093] In this example, the main surface of each layer may be a surface substantially perpendicular to the thickness direction of the negative electrode 140. In each layer, one of the two main surfaces may be a smooth surface (sometimes called a shiny surface or S surface). The other of the two main surfaces may be a rough surface (sometimes called a matte surface or M surface). The side surface of each layer may be a surface that extends in the thickness direction of the negative electrode 140.

[0094] For the purpose of simplifying the explanation, in this example, an example of the negative electrode 140 is described using the case where the negative electrode current collector 320 and the negative electrode active material layer 340 have a rectangular plate shape or a rectangular prism shape. However, the shape of the negative electrode current collector 320 and the negative electrode active material layer 340 is not limited to this example.

[0095] (Negative electrode current collector) In this example, the negative electrode current collector 320 electrically connects the negative electrode lead 174 and the negative electrode active material layer 340. As the negative electrode current collector 320, a material that does not react with lithium or a material with poor reactivity with lithium is used.

[0096] In one embodiment, the negative electrode current collector 320 is composed of one or more metal materials, one or more conductive resins, one or more carbon materials, and combinations thereof. Examples of the above-mentioned metal materials include copper, aluminum, stainless steel, nickel, titanium, or alloys thereof.

[0097] In a modified example, the negative electrode current collector 320 comprises a resin support layer and a metal layer disposed on the surface of the support layer. Examples of the resin include polyethylene, polypropylene, polyethylene terephthalate, and polyimide. The metal layer may be made of copper, aluminum, stainless steel, nickel, titanium, or an alloy thereof. The metal layer may include a layer made of copper, aluminum, stainless steel, nickel, titanium, or an alloy thereof. The metal layer may be a foil or a plated layer.

[0098] Examples of the shape of the negative electrode current collector 320 include foil, mesh, punched metal, expanded metal, and combinations thereof. The thickness of the negative electrode current collector 320 is not particularly limited, but may be 5 to 200 μm. Preferably, the thickness of the negative electrode current collector 320 is 6 to 20 μm.

[0099] (Negative electrode active material layer) In this example, the negative electrode active material layer 340 is disposed on at least one surface of the negative electrode current collector 320. In this example, the negative electrode active material layer 340 is disposed on the first main surface 322 of the negative electrode current collector 320. The second main surface 344 of the negative electrode active material layer 340 may be in contact with the first main surface 322 of the negative electrode current collector 320.

[0100] In this example, the negative electrode active material layer 340 contains a negative electrode active material. The negative electrode active material layer 340 may be composed of foil-like or film-like negative electrode active material. Various metals are exemplified as negative electrode active material. The negative electrode active material may contain at least one metal selected from the group consisting of alkali metals, magnesium metals, zinc metals, and aluminum metals.

[0101] In one embodiment, the negative electrode active material may be at least one selected from the group consisting of alkali metals, alloys containing alkali metals, and composite oxides containing alkali metals. In a modified example, the negative electrode active material may be an alkali metal and / or a composite oxide containing alkali metals. In a further modified example, the negative electrode active material may be an alkali metal. The alkali metal may be lithium metal and / or sodium metal. As described above, these negative electrode active materials may have a foil-like or film-like shape.

[0102] The alkali metal may be lithium metal. The negative electrode 140 may be a lithium metal negative electrode. In this case, the storage battery 100 is the lithium metal storage battery described above, and the electrode potential of the negative electrode 140 with respect to Li / Li+ is, for example, 0.5V or less. The above electrode potential may be 0.2V or less, or 0.1V or less. If the storage battery 100 is a lithium-ion battery, the electrode potential of the negative electrode 140 with respect to Li / Li+ is, for example, 0.05V or more and 3.0V or less.

[0103] In one embodiment, the alkali metal is configured to deposit and dissolve alkali metal ions in the negative electrode 140. For example, if the storage battery 100 is a non-aqueous electrolyte secondary battery, alkali metal is deposited on the negative electrode 140 when the storage battery 100 is charged. For example, alkali metal is deposited on the surface of the negative electrode current collector 320. On the other hand, when the storage battery 100 is discharged, the alkali metal of the negative electrode 140 dissolves in the non-aqueous electrolyte 150. In this case, for example, one or more metal materials are used as the negative electrode current collector 320.

[0104] In one embodiment, the alkali metal is configured in the negative electrode 140 to absorb and release alkali metal ions. For example, if the storage battery 100 is a non-aqueous electrolyte secondary battery, the negative electrode 140 absorbs alkali metal ions when the storage battery 100 is being charged. For example, the negative electrode active material layer 340 absorbs alkali metal ions (this may be referred to as alkali metal ions being inserted into the negative electrode active material layer 340). On the other hand, when the storage battery 100 is being discharged, the negative electrode 140 releases alkali metal ions into the non-aqueous electrolyte 150.

[0105] In one embodiment, one or more carbon materials may be used as the negative electrode active material layer 340. That is, the negative electrode 140 may be a graphite negative electrode. In a modified example, one or more silicon materials may be used as the negative electrode active material layer 340. That is, the negative electrode 140 may be a silicon oxide negative electrode or a silicon negative electrode.

[0106] The negative electrode active material layer 340 may consist of a single layer or multiple layers. If the negative electrode active material layer 340 consists of multiple layers, it may include a first layer containing negative electrode active material and a second layer made of a conductive material. The second layer may contain less negative electrode active material than the first layer, or may not contain negative electrode active material at all. In this case, the second layer may be in contact with the negative electrode current collector 320, and the first layer may be electrically connected to the negative electrode current collector 320 via the second layer.

[0107] If the negative electrode active material layer 340 is composed of multiple layers, the negative electrode active material layer 340 may include a resin support layer and a layer containing the negative electrode active material. In this case, the layer containing the negative electrode active material may be formed on one surface of the support layer or on both surfaces of the support layer.

[0108] The thickness of the negative electrode active material layer 340 may be 1 to 500 μm, 10 to 200 μm, or 50 to 100 μm. When a foil-like or film-like alkali metal (sometimes referred to as alkali metal foil) is used as the negative electrode active material layer 340, the thickness of the alkali metal foil may be 10 to 200 μm or 50 to 100 μm. The thickness and / or mass of the alkali metal foil may be determined according to the content of the positive electrode active material in the positive electrode active material layer 240.

[0109] In one embodiment, the negative electrode active material layer 340 is made by processing the material used as the negative electrode active material into a foil or sheet. In a modified example, the negative electrode active material layer 340 is formed by depositing the material constituting the negative electrode active material layer 340 on at least one surface of a resin support layer by (i) slurry coating, (ii) physical vapor deposition (PVD) methods such as sputtering, vapor deposition, and ion plating, (iii) chemical vapor deposition (CVD), or (iv) atomic layer deposition (ALD).

[0110] In the electrode structure 110, the positive electrode 120 is positioned on the side of the first main surface 132 of the separator 130. On the other hand, the negative electrode 140 is positioned on the side of the second main surface 134 of the separator 130. In this case, the first main surface 342 of the negative electrode active material layer 340 may be in contact with the second main surface 134 of the separator 130. The negative electrode 140 is in contact with the complex-containing layer 135 provided on the second main surface 134 of the separator 130.

[0111] (Example of modification) The negative electrode 140 does not have a negative electrode current collector 320. If the negative electrode 140 does not have a negative electrode current collector 320, the negative electrode active material layer 340 may have the function of the negative electrode current collector 320. Such a negative electrode 140 is used, for example, in a battery having an electrolyte containing alkali metal ions, or a battery using alkali metal ions as carriers. The above battery is manufactured, for example, by assembling a battery structure including the above negative electrode 140 and an electrolyte containing alkali metal ions into a battery housing. The above battery may also be a metal negative electrode battery.

[0112] When the above-described negative electrode 140 is incorporated into, for example, a storage battery 100 that uses alkali metal ions as a carrier, alkali metal is deposited on the surface of the negative electrode current collector 320 during charging of the storage battery 100. The alkali metal is derived, for example, from alkali metal ions contained in the electrolyte of the storage battery 100. This forms an alkali metal negative electrode active material layer 340. As a result, a negative electrode 140 is manufactured having a laminate in which the negative electrode current collector 320 and the negative electrode active material layer 340 are stacked in this order.

[0113] Figure 4 schematically shows an example of a separator 130. In this example, the separator 130 comprises a complex-containing layer 135 and a base layer 440. The separator 130 has a first main surface 132 and a second main surface 134.

[0114] In this example, for the purpose of simplifying the explanation, the details of the separator 130 will be described using the example where the complex-containing layer 135 is arranged on one side of the base layer 440. However, the separator 130 is not limited to this example. In a modified example, the complex-containing layer 135 may be arranged on both sides of the base layer 440.

[0115] The base layer 440 is a region of the separator 130 that does not contain the electrolyte complex. That is, the base layer 440 may be a region of the separator 130 that remains uncoated with the electrolyte complex. In the example in Figure 4, since the electrolyte complex is coated from the second main surface 134 side of the separator 130, the base layer 440 remains on the first main surface 132 side of the separator 130.

[0116] In the modified example, the base layer 440 may not be provided. The entire separator 130 may be coated with an electrolyte complex to form a complex-containing layer 135.

[0117] The thickness of the complex-containing layer 135 may be 10% or more, 1% or more, or 0.1% or more of the thickness of the base layer 440. The thickness of the complex-containing layer 135 may be 500% or less, 200% or less, or 50% or less of the thickness of the base layer 440. In this example, the thickness of the complex-containing layer 135 is 0.01 μm or more and 20 μm or less.

[0118] The separator 130 is arranged so that the complex-containing layer 135 and the negative electrode 140 are in contact. In the example shown in Figure 4, the first main surface 342 of the negative electrode 140 and the second main surface 134 of the separator 130 are facing each other.

[0119] The separator 130 and the negative electrode 140 may form a battery structure 450. The storage battery 100 in this example may have a structure in which the battery structure 450, which includes the separator 130 and the negative electrode 140 in contact with the complex-containing layer 135 of the separator 130, and the positive electrode 120 are stacked in this order.

[0120] Figure 5 schematically shows an example of the electrode structure 510. The electrode structure 510 is another example of the electrode structure 110. The electrode structure 510 differs from the electrode structure 110 in that it has a wound structure. The electrode structure 510 may have the same configuration as the electrode structure 110, except for the above-mentioned difference.

[0121] In this example, the electrode structure 510 is manufactured by winding a sheet in which a positive electrode 120, a separator 130, a negative electrode 140, and another separator 130 are stacked in this order into a roll. Although not shown in Figure 5, in this example as well, a complex-containing layer 135 is provided on the surface of the separator 130 that is in contact with the negative electrode 140. In this example, a positive electrode tab 122 is provided at one end of the positive electrode 120. A negative electrode tab 142 is provided at one end of the negative electrode 140.

[0122] (Example of Modification) In this example, an example of an electrode structure 510 has been described, in which the electrode structure 510 comprises a single positive electrode tab 122 and a single negative electrode tab 142. However, the electrode structure 510 is not limited to this example. In a modification, the electrode structure 510 may have a plurality of negative electrode tabs 142. Also, the electrode structure 510 may have a plurality of positive electrode tabs 122.

[0123] Figure 6 schematically shows an example of a method for manufacturing a storage battery 100. In this example, an example of a method for manufacturing a storage battery 100 equipped with the battery structure 450 described in relation to Figure 4 is described.

[0124] In this example, first, in step 610 (the step may be referred to as S), the negative electrode 140 is prepared. Specifically, for example, a foil-like or film-like active material containing an alkali metal is prepared. As described above, examples of the active material included in the negative electrode 140 include at least one selected from the group consisting of alkali metals, alloys containing alkali metals, and composite oxides containing alkali metals. The above active material may be an alkali metal or a composite oxide containing an alkali metal.

[0125] In this example, in step S620, the separator 130 is prepared. Specifically, an organic solvent containing an electrolyte complex is coated onto a polyethylene film or the like, and after drying, it is cut to a predetermined size to prepare the separator 130 having a complex-containing layer 135.

[0126] In this example, in S630, the positive electrode 120 and the battery structure 450 are prepared. In S640, the electrode structure 110 is assembled using the positive electrode 120 and the battery structure 450. Specifically, the negative electrode 140 is placed on the side of the separator 130 that has the complex-containing layer 135, and the battery structure 450 is prepared. In this example, the negative electrode 140 is placed on the side of the second main surface 134. In addition, the positive electrode 120 is placed on the side of the separator 130 that has the first main surface 132 of the battery structure 450. The above process is repeated to assemble the electrode structure 110. This results in an electrode structure 110 comprising the positive electrode 120, the separator 130, and the negative electrode 140.

[0127] Next, in S650, the storage battery 100 is assembled using the electrode structure 110. Specifically, the electrode structure 110 and the non-aqueous electrolyte 150 are housed inside the battery case 160. For example, after the electrode structure 110 is placed inside the battery case 160, the non-aqueous electrolyte 150 is filled inside the battery case 160. This completes the storage battery 100.

[0128] Step 610 may be an example of a method for producing electrodes. Steps 610 to 640 may be an example of a method for producing a battery structure.

[0129] For the purpose of further explaining the storage battery 100, the details of the storage battery 100 will be described by the following embodiment. However, various modifications or improvements may be made to the following embodiment, and the storage battery 100 is not limited to the following embodiment.

[0130] (Nitrate production 1) Lithium nitrate (LiNO) ３ A mixture of 6 g of lithium nitrate (98% purity, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) and 100 g of 1,2-dimethoxyethane was prepared and heated to 40°C to dissolve lithium nitrate. When this solution was cooled to 25°C, crystals precipitated. The precipitated crystals were filtered, washed with dimethyl carbonate (DMC), and dried at 80°C to obtain needle-shaped crystals of lithium nitrate.

[0131] (Production of nitrates 2 to 5) Lithium nitrate (LiNO) ３ Instead of ), cesium nitrate (CsNO) ３ ), silver nitrate (AgNO) ３ ), calcium nitrate (Ca(NO) ３ ) ２ ), indium nitrate (In(NO ３ ) ３ Except for using ), the nitrates shown in Table 1, from (Nitrate Production 2) to (Nitrate Production 5), were obtained using the same method as in (Nitrate Production 1). Subsequently, the IR spectra and ionic conductivity of the nitrates obtained from (Nitrate Production 1) to (Nitrate Production 5) were measured.

[0132] (Measurement of IR spectrum) The crystals obtained in (Nitrate production 1) to (Nitrate production 5) above were crushed in a mortar to obtain a fine powder. Under conditions with a dew point of -10°C or lower, the nitrate complex was fixed in a holder inside a thunderdome and measured using an FT-IR spectrometer in a spectral range of 4,000 to 400 cm². －１ , resolution 4cm －１ The infrared absorption spectra were measured under the condition of 128 scans. Table 1 shows the wavenumbers of the peaks originating from the nitro group of each nitrate. As shown in Table 1, each nitrate obtained from (nitrate production 1) to (nitrate production 5) was measured at 1400 cm⁻¹. －１ A peak was observed in the vicinity.

[0133] (Measurement of Ionic Conductivity) The crystals obtained from (Nitrate Production 1) to (Nitrate Production 5) above were crushed in a mortar to obtain a fine powder. Under conditions with a dew point of -10°C or lower, the nitrate complex was placed in a stainless steel mold and molded into pellets with a thickness of 1 mm and a diameter of 10 mm at a pressure of 10 MPa. After applying conductive carbon to both sides of the pellets, they were sandwiched in a stainless steel electrode holder, and the ionic conductivity was measured using an impedance analyzer (Solartron, VSP-300) in the frequency range of 7 MHz to 1 Hz. Table 1 shows the ionic conductivity of each nitrate pellet. As shown in Table 1, each nitrate obtained from (Nitrate Production 1) to (Nitrate Production 5) showed an ionic conductivity in the range of 1 μS / cm to 6 μS / cm. [Table 1]

[0134] (Preparation of Electrolyte Complex 1-1) In an environment with a dew point of -10°C or lower, fluoroethylene carbonate (FEC) was mixed with the nitrate obtained in (Nitrate Production 1) as a coordinating agent in a mortar in a molar ratio of 1:1. This yielded Electrolyte Complex 1-1.

[0135] (Preparation of Electrolyte Complexes 1-2 to 1-5) The electrolyte complexes listed in Table 2, from (Electrolyte Complex 1-2) to (Preparation of Electrolyte Complex 1-5), were obtained using the same method as in (Preparation of Electrolyte Complex 1-1), except that the molar ratios were changed. Specifically, fluoroethylene carbonate (FEC) was mixed in a mortar with the nitrate obtained in (Production of Nitrate 1) as a coordinating substance in molar ratios of 1:0.01, 1:0.1, 1:2, and 1:5, respectively. Subsequently, the IR spectra and ionic conductivity of the electrolyte complexes obtained from (Electrolyte Complex 1-1) to (Preparation of Electrolyte Complex 1-5) were measured.

[0136] (Preparation of Electrolyte Complexes 2-1 to 2-2) The electrolyte complexes listed in Table 2, from (Electrolyte Complex 2-1) to (Preparation of Electrolyte Complex 2-2), were obtained using the same method as in (Preparation of Electrolyte Complex 1-1), except that the coordinating substances were changed. Specifically, vinylene carbonate (VC) and 1,2-dimethoxyethane (DME), respectively, were mixed in a mortar with a molar ratio of 1:1 to the nitrate obtained in (Production of Nitrate 1). Subsequently, the IR spectra and ionic conductivity of the electrolyte complexes obtained from (Electrolyte Complex 2-1) to (Preparation of Electrolyte Complex 2-2) were measured.

[0137] (Preparation of Electrolyte Complexes 3-1 to 3-4) The electrolyte complexes listed in Table 2, from (Electrolyte Complex 3-1) to (Preparation of Electrolyte Complex 3-4), were obtained using the same method as in (Preparation of Electrolyte Complex 1-1), except that the nitrate was changed. Specifically, fluoroethylene carbonate (FEC) was mixed in a mortar with a molar ratio of 1:1 as a coordinating agent to the nitrates obtained in (Nitrate Production 2) to (Nitrate Production 5). Subsequently, the IR spectra and ionic conductivity of the electrolyte complexes obtained in (Electrolyte Complex 3-1) to (Preparation of Electrolyte Complex 3-4) were measured.

[0138] (Measurement of IR Spectra) The method for measuring the IR spectrum is the same as the method for measuring the IR spectrum of the nitrates obtained in (Nitrate Production 1) to (Nitrate Production 5), so the explanation is omitted. Table 2 shows the wavenumbers of the peaks of the electrolyte complexes obtained in (Electrolyte Complex 1-1) to (Preparation of Electrolyte Complex 3-4).

[0139] The electrolyte complex obtained in (Preparation of Electrolyte Complex 1-1) has a peak position shifted to lower wavenumbers compared to the nitrate obtained in (Production of Nitrate 1). Furthermore, the electrolyte complex obtained in (Preparation of Electrolyte Complex 1-3), where the molar ratio of the coordinating substance to the nitrate is smaller than that of the electrolyte complex obtained in (Preparation of Electrolyte Complex 1-1), has a peak position on the higher wavenumber side. The electrolyte complex obtained in (Preparation of Electrolyte Complex 1-2), where the molar ratio of the coordinating substance to the nitrate is even smaller than that of the electrolyte complex obtained in (Preparation of Electrolyte Complex 1-3), has a peak position on the even higher wavenumber side. These results are thought to be due to the formation of a complex by adding a coordinating substance to the nitrate.

[0140] The peak positions of the electrolyte complexes obtained in (Preparation of Electrolyte Complex 1-4) and (Preparation of Electrolyte Complex 1-5) did not change from the peak positions of the electrolyte complex obtained in (Preparation of Electrolyte Complex 1-1). These results are thought to be due to the saturation of coordinate bond formation by mixing fluoroethylene carbonate (FEC) as a coordinating agent with the nitrate obtained in (Production of Nitrate 1) in a molar ratio of 1:1 or higher.

[0141] The electrolyte complex obtained from (Electrolyte Complex 2-1) to (Preparation of Electrolyte Complex 2-2) has a peak position shifted to the lower wavenumber side compared to the nitrate obtained in (Production of Nitrate 1). Thus, it can be seen that a complex is formed even when vinylene carbonate (VC) and 1,2-dimethoxyethane (DME) are used instead of fluoroethylene carbonate (FEC) as coordinating agents.

[0142] The electrolyte complexes obtained from (Electrolyte Complex 3-1) to (Preparation of Electrolyte Complex 3-4) above have peaks that are shifted to lower wavenumbers compared to the nitrates obtained from (Nitrate Production 2) to (Nitrate Production 5), respectively. Thus, lithium nitrate (LiNO) is used as the nitrate. ３ Instead of ) cesium nitrate (CsNO) ３ ), silver nitrate (AgNO) ３ ), calcium nitrate (Ca(NO) ３ ) ２ ), indium nitrate (In(NO ３ ) ３ It can be seen that a complex is formed even when using (electrolyte complex 1-1) and (preparation of electrolyte complex 3-4). Thus, the electrolyte complex obtained from (electrolyte complex 1-1) to (preparation of electrolyte complex 3-4) shows that the peak position is 1400 cm due to complex formation. －１ Approximately 1350 cm from the vicinity －１ Above, 1395cm －１ Shift to the following range:

[0143] (Measurement of Ionic Conductivity) The method for measuring ionic conductivity is the same as the method for measuring the ionic conductivity of nitrates obtained in (Nitrate Production 1) to (Nitrate Production 5), so the explanation is omitted. Table 2 shows the ionic conductivity of the electrolyte complexes obtained in (Electrolyte Complex 1-1) to (Preparation of Electrolyte Complex 3-4).

[0144] The electrolyte complexes obtained from (Electrolyte Complex 1-1) to (Preparation of Electrolyte Complex 3-4) all exhibit higher ionic conductivity than the nitrates obtained from (Nitrate Production 1) to (Nitrate Production 5). Thus, by mixing a coordinating agent with the nitrate, the ionic conductivity is improved compared to when the nitrate is used alone. [Table 2]

[0145] (Separator preparation 1-1) 0.2 g of fine particles obtained in (Electrolyte complex preparation 1-1) were added to 4 g of dimethyl carbonate (DMC), and a dispersion was obtained by sonication. The dispersion was applied to polyethylene film (Celgard, USA, #2320) using the doctor blade method, and then dried under reduced pressure at 60°C for 10 minutes to remove the DMC. Separator 1-1 was then prepared by cutting it into a flat shape of 45 mm in length and 45 mm in width.

[0146] (Separator preparation 1-2 to 1-17) Separator 1-17 was prepared from separator 1-2 shown in Table 3 using the same method as in (Separator preparation 1-1), except for changing the type of electrolyte complex. Specifically, separator 1-17 was prepared from separator 1-2 using the electrolyte complexes obtained in (Preparation of electrolyte complexes 1-2 to 1-5, 2-1, 2-2, 3-1 to 3-4) described above.

[0147] (Separator Preparation 2-1) 0.02 g of polyvinylidene fluoride (PVDF) and 4 g of N-methyl-2-pyrrolidinone (NMP) were mixed as a binder to obtain an NMP binder solution. Then, 0.2 g of the electrolyte complex obtained in (Electrolyte Complex 1-1) was added, and the mixture was sonicated to obtain a dispersion. The dispersion was applied to a polyethylene film (Celgard, USA, #2320) using the doctor blade method, and then dried under reduced pressure at 60°C for 10 minutes to remove DMC. Separator 2-1 was then prepared by cutting it into a planar shape of 45 mm in length and 45 mm in width.

[0148] (Separator Preparation 2-2 to 2-17) Separators 2-2 to 2-17 shown in Table 3 were prepared using the same method as in (Separator Preparation 2-1), except for changing the type of electrolyte complex. Specifically, separators 2-2 to 2-17 were prepared using the electrolyte complexes obtained in (Preparation of Electrolyte Complexes 1-2 to 1-5, 2-1 to 2-2, 3-1 to 3-4) described above. [Table 3]

[0149] (Separator Fabrication 3-1) An uncoated separator was fabricated. Specifically, polyethylene film (Celgard, USA, #2320) was cut into a flat shape of 45 mm in length and 45 mm in width to produce the separator fabrication 3-1 shown in Table 4.

[0150] (Separator Preparation 3-2) 0.2 g of fine particles obtained in (Nitrate Production 1) above were added to 4 g of DMC and ultrasonically treated to obtain a dispersion. The dispersion was applied to polyethylene film (Celgard, USA, #2320) using the doctor blade method, then dried under reduced pressure at 60°C for 10 minutes to remove the DMC, and cut into a flat shape of 45 mm in length and 45 mm in width to prepare separator 3-1.

[0151] (Separator preparation 3-3 to 3-6) Separators 3-2 to 3-6 shown in Table 4 were prepared using the same method as in (Separator preparation 3-2), except for changing the type of nitrate. Specifically, separators 3-2 to 3-6 were prepared using the nitrates obtained in (Nitrate production 2) to (Nitrate production 5) above.

[0152] (Separator preparation 3-7) 0.02 g of polyvinylidene fluoride (PVDF) and 4 g of N-methyl-2-pyrrolidinone (NMP) were mixed as a binder to obtain an NMP binder solution. Then, 0.2 g of the electrolyte complex obtained in (Nitrate preparation 1) was added, and the mixture was sonicated to obtain a dispersion. The dispersion was applied to a polyethylene film (Celgard, USA, #2320) using the doctor blade method, and then dried under reduced pressure at 60°C for 10 minutes to remove DMC. Separator 3-7 was then prepared by cutting it into a planar shape of 45 mm in length and 45 mm in width.

[0153] (Separator Preparation 3-8 to 3-11) Separators 3-8 to 3-11 shown in Table 4 were prepared using the same method as in (Separator Preparation 3-7), except for changing the type of nitrate. Specifically, separators 3-8 to 3-11 were prepared using the nitrates obtained in (Nitrate Production 2) to (Nitrate Production 5) above. [Table 4]

[0154] (Preparation of test NCM cathode) An NCM cathode was prepared according to the following procedure. First, as the cathode active material, the median diameter (D) based on the number of particles was prepared. ５０ ) is 5 μm NCM (LiNi １／３ Mn １／３ Co １／３ O ２ We prepared the following: Carbon black and graphite as conductive additives. Polyvinylidene fluoride (PVDF) as a binder.

[0155] Next, PVDF and N-methyl-2-pyrrolidinone (NMP) were mixed to prepare 50 g of a PVDF-NMP solution. The PVDF content in the NMP solution was 10 wt%. Next, 85 g of NCM, 5 g of carbon black, and 5 g of graphite were mixed. Then, the above mixture was mixed with the 50 g of the PVDF-NMP solution to prepare 145 g of paint.

[0156] Next, the above-mentioned paint was applied to the surface of an aluminum foil with a thickness of 20 μm using the doctor blade method. By drying the above-mentioned paint at a temperature of 90°C, an aluminum foil with a positive electrode active material layer formed on it was obtained. After that, the above-mentioned aluminum foil was cut into a square of 40 mm in length and 40 mm in width, and terminals were welded to it. This created a positive electrode.

[0157] (Fabrication of Lithium Metal Anode) A lithium metal foil with a thickness of 100 μm and a purity of 99.5% or higher was prepared. The planar shape of the lithium metal foil was a square with dimensions of 40 mm in length and 40 mm in width. The lithium metal foil was placed on the anode current collector. Next, terminals were welded to the metal foil. This completed the fabrication of the lithium metal anode.

[0158] (Preparation of graphite anode) SCMG (registered trademark)-AR powder (manufactured by Showa Denko K.K.) was used as the artificial graphite, and natural graphite particles (average particle size 25 μm) (manufactured by Kansai Thermal Chemical Co., Ltd.) were used as the natural graphite. The artificial graphite and natural graphite were uniformly dispersed in NMP (polymeric polymer) in which PVDF (a binder) had been dissolved beforehand, and then NMP for viscosity adjustment was added to prepare a mixture paste of artificial graphite and natural graphite.

[0159] This paste was applied to copper foil (current collector), dried, and pressurized. After processing to a predetermined size (40 mm vertically, 40 mm horizontally), terminals were welded to obtain a graphite negative electrode. The solid content ratio in the negative electrode was set to artificial graphite powder:natural graphite powder:PVDF = 72:18:10 (mass ratio). The amounts of NMC positive electrode active material, artificial graphite, and natural graphite were adjusted so that the charging capacity of the graphite negative electrode was greater than that of the NMC positive electrode. The amount of coating was also adjusted to prevent lithium metal from precipitation on the graphite negative electrode during charging.

[0160] (Fabrication of silicon oxide anode) As silicon oxide powder, disproportionated silicon oxide powder (manufactured by Sigma-Aldrich Japan Co., Ltd., SiO2) is used. ｘ (x is 0.3 to 1.6, average particle size 5 μm), and MAG-D (particle size 20 μm or less) (manufactured by Hitachi Chemical Co., Ltd.) was used as the bulk artificial graphite powder. The mixed powder of silicon oxide powder and bulk artificial graphite powder was uniformly dispersed in NMP in which PVDF as a binder had been dissolved in advance, and Ketjenblack (conductive agent) was added and mixed. Furthermore, NMP for viscosity adjustment was added, and SiO ｘ A compound paste was prepared.

[0161] This paste was applied to copper foil (current collector), dried, and pressurized. After processing to a predetermined size (40 mm vertically, 40 mm horizontally), terminals were welded to obtain a silicon oxide negative electrode. The solid content ratio in the negative electrode was SiO ｘ The ratio of MAGD, conductive agent, and PVDF was set to 35:47:8:10 (mass ratio). Furthermore, the NMC cathode active material and SiO were adjusted so that the charging capacity of the silicon oxide anode was greater than that of the NMC cathode. ｘ The amount of powder was adjusted, and the coating amount was also adjusted to prevent lithium metal from depositing on the silicon oxide negative electrode during charging.

[0162] (Preparation of Silicon Anode) As the Si powder, a mixed powder of Si powder (average particle size: 10 μm / 6 μm = mass ratio 9 / 1) was used. The Si powder was uniformly dispersed in NMP in which PVDF, which is a binder, had been dissolved in advance, and then Ketjenblack (conductive agent 1) and vapor-phase carbon fiber (VGCF®, manufactured by Showa Denko) (conductive agent 2) were added and mixed. Furthermore, NMP for viscosity adjustment was added to prepare the Si mixture paste.

[0163] This paste was applied to copper foil (current collector), dried, and pressurized. After processing to a predetermined size (40 mm vertically, 40 mm horizontally), terminals were welded to obtain a silicon anode. The solid content ratio in the anode was Si powder:conductive agent 1:conductive agent 2:PVDF = 78:7:3:12 (mass ratio). The amounts of NMC positive electrode active material and Si powder were adjusted so that the charging capacity of the silicon anode was greater than that of the NMC positive electrode, and the amount of coating was adjusted so that lithium metal would not precipitate on the silicon anode during charging.

[0164] (Preparation of Electrolyte 1) Electrolyte 1 to be used in Example 1 was prepared according to the following procedure. After dissolving the electrolyte in a non-aqueous solvent while cooling so that the liquid temperature does not exceed 40°C, other raw materials were added and mixed and stirred to prepare the solution so that the following raw materials were in the specified mass %. Specifically, a mixed solvent of ethylene carbonate (EC, manufactured by Kishida Chemical Co., Ltd., purity 99.5%) and dimethyl carbonate (DMC, manufactured by Kishida Chemical Co., Ltd., purity 99.5%) (EC:DMC = 23:60 mass%) was mixed with lithium hexafluoride phosphate (LiPF) ６ Dissolve 12% by mass of 99.9% purity fluoride from Kishida Chemical Co., Ltd., and add 5% by mass of 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE, manufactured by Tokyo Chemical Industry Co., Ltd., 95% purity) as hydrofluoroether (HFE), then mix and stir. This yielded electrolyte 1.

[0165] (Preparation of Electrolyte 2) Electrolyte 2 was prepared in the same manner as described above (Preparation of Electrolyte 1), except that fluoroethylene carbonate (FEC, manufactured by Kishida Chemical Co., Ltd., purity 99.5%) was used as the non-aqueous solvent instead of ethylene carbonate (EC).

[0166] (Example 1) Test pouch cells were prepared. Specifically, test pouch cells were prepared according to the following procedure.

[0167] (Preparation of test laminate) The separator obtained in (Preparation of separator 1-1) above was placed on the surface of the lithium metal negative electrode where the lithium foil was arranged, with the complex-containing layer in contact with the lithium foil. Next, the positive electrode was placed on the separator so that the surface of the positive electrode active material of the positive electrode was in contact with the surface of the separator. As a result, a laminate was obtained in which the negative electrode, separator and positive electrode were laminated in this order.

[0168] (Preparation of test pouch cell) First, the above laminate was placed inside a bag-shaped aluminum laminate having an opening. Next, the electrolyte 1 prepared in (Preparation of electrolyte 1) above was vacuum injected into the aluminum laminate. Then, the opening of the aluminum laminate was heated and sealed. This produced the test pouch cell described in Example 1 of Table 5.

[0169] (Examples 2 to 17) The test pouch cells described in Examples 2 to 17 in Table 5 were prepared by following the same procedure as in Example 1, except that the type of separator was changed. Specifically, the test pouch cells described in Examples 2 to 17 were prepared using the separators obtained in (Separator Preparation 1-2 to 1-17) above.

[0170] (Examples 18 to 34) The test pouch cells described in Examples 18 to 34 in Table 5 were prepared using the same procedure as in Example 1, except that the type of separator was changed. Specifically, the test pouch cells described in Examples 18 to 34 were prepared using the separators obtained in (Separator Preparation 2-1 to 2-17) above. [Table 5]

[0171] (Examples 35 to 68) The test pouch cells described in Examples 35 to 68 in Table 6 were prepared by following the same procedure as in Example 1, except that the type of electrolyte was changed. Specifically, the separators obtained in (Separator Preparation 1-1 to 1-17, 2-1 to 2-17) above were used, and (Electrolyte 2) was used instead of (Electrolyte 1) as the electrolyte to prepare the test pouch cells described in Examples 35 to 68. [Table 6]

[0172] (Examples 69 to 80) The test pouch cells described in Examples 69 to 80 in Table 7 were prepared by following the same procedure as in Example 1, except that the type of negative electrode was changed. Specifically, the test pouch cells described in Examples 69 to 80 were prepared by using a graphite negative electrode instead of a lithium metal negative electrode, and by using the separator obtained in (Separator Preparation 1-1, 1-6, 1-7, 2-1, 2-6 and 2-7) above, and (Electrolyte 1) or (Electrolyte 2) above. [Table 7]

[0173] (Examples 81 to 92) The test pouch cells described in Examples 81 to 92 in Table 8 were prepared by following the same procedure as in Example 1, except that the type of negative electrode was changed. Specifically, the test pouch cells described in Examples 81 to 92 were prepared by using a silicon oxide negative electrode instead of a lithium metal negative electrode, and by using the separator obtained in (Separator Preparation 1-1, 1-6, 1-7, 2-1, 2-6 and 2-7) above, and (Electrolyte 1) or (Electrolyte 2) above. [Table 8]

[0174] (Examples 93 to 104) The test pouch cells described in Examples 93 to 104 in Table 9 were prepared by following the same procedure as in Example 1, except that the type of negative electrode was changed. Specifically, the test pouch cells described in Examples 93 to 104 were prepared by using a silicon negative electrode instead of a lithium metal negative electrode, and by using the separator obtained in (Separator Preparation 1-1, 1-6, 1-7, 2-1, 2-6 and 2-7) above, and (Electrolyte 1) or (Electrolyte 2) above. [Table 9]

[0175] (Comparative Example 1) A test pouch cell described in Comparative Example 1 in Table 10 was prepared by following the same procedure as in Example 1, except that the type of separator was changed. Specifically, a separator without nitrate coating, obtained in (Separator Preparation 3-1) above, was used.

[0176] (Comparative Examples 2 to 40) Except for changing the type of separator, the type of negative electrode, and the type of electrolyte, the test pouch cells described in Comparative Examples 2 to 40 in Table 10 were prepared using the same procedure as in Comparative Example 1. In Comparative Examples 2 to 8, the nitrate-uncoated separator obtained in (Separator Preparation 3-1) above was used, and the test pouch cells were prepared by changing the type of negative electrode and the type of electrolyte. In Comparative Examples 9 to 18, the separator obtained in (Separator Preparation 3-2 to 3-11) above was used, and the test pouch cells were prepared using a lithium metal negative electrode and electrolyte 1. In Comparative Examples 19 to 28, the separator obtained in (Separator Preparation 3-2 to 3-11) above was used, and the test pouch cells were prepared using a lithium metal negative electrode and electrolyte 2. In Comparative Examples 29 to 40, the separators obtained in (Separator Preparation 3-2) or (Separator Preparation 3-7) above were used, and instead of a lithium metal anode, a graphite anode, a silicon oxide anode, or a silicon anode was used as the negative electrode. Test pouch cells were prepared using electrolyte 1 or electrolyte 2. [Table 10]

[0177] (Evaluation) A cycle test was performed on each test pouch cell prepared in each example and comparative example. Specifically, the test pouch cells were charged and discharged at 0.1C in a 25°C environment, and the initial charge / discharge capacity was measured. Then, the ratio of the discharge capacity to the initial charge / discharge capacity after a predetermined number of charge / discharge cycles under the charge / discharge conditions shown in Tables 5 to 10 was calculated and defined as the discharge capacity retention rate (%). The evaluation results of the cycle tests in each example and comparative example are shown in Tables 5 to 10.

[0178] (1) Evaluation by coating with nitrate or electrolyte complex: As shown in Comparative Example 1 of Table 10, when separator 3-1 without nitrate coating was used, a short circuit occurred before reaching 200 cycles. In contrast, as shown in Comparative Example 9 of Table 10, the cycle characteristics were improved by using separator 3-2 coated with lithium nitrate as the nitrate. Furthermore, as shown in Example 1 of Table 5, when separator 1-1 coated with electrolyte complex 1-1, which is a mixture of lithium nitrate and a coordinating agent (FEC), was used, the cycle characteristics were further improved. Thus, in this example, by coating the separator with an electrolyte complex, which is a mixture of nitrate and a coordinating agent, the cycle characteristics can be improved compared to the case of no coating and the case of coating with nitrate only.

[0179] (2) Evaluation based on the amount of coordination substance As shown in Example 2 of Table 5, even when the molar ratio of nitrate to coordination substance (FEC) was reduced to 1:0.01, the cycle characteristics were improved compared to Comparative Example 9 in Table 10. Also, as shown in Examples 3 to 5 of Table 5, when the amount of coordination substance relative to nitrate was increased, the cycle characteristics were improved. Thus, in this example, by mixing the coordination substance with nitrate at a molar ratio of 1% or more, the cycle characteristics can be improved compared to when no coordination substance is mixed.

[0180] (3) Evaluation by type of coordination substance As shown in Examples 6 and 7 of Table 5, even when VC or DME was used instead of FEC as the coordination substance, the cycle characteristics were improved compared to Comparative Example 9 in Table 10. Thus, in this example, cycle characteristics can be improved even when a coordination substance that does not contain fluorine atoms is used.

[0181] (4) Evaluation by type of nitrate As shown in Comparative Examples 10 to 13 of Table 10, lithium nitrate (LiNO) ３ Instead of ) cesium nitrate (CsNO) ３ ), silver nitrate (AgNO) ３ ), calcium nitrate (Ca(NO) ３ ) ２ ), indium nitrate (In(NO ３ ) ３Even when separators 3-3 to 3-6 coated with ) were used, the cycle characteristics were improved compared to Comparative Example 1, which used uncoated separator 3-1. Furthermore, as shown in Examples 8 to 11 in Table 5, lithium nitrate (LiNO) was used. ３ When separators 1-8 to 1-11 coated with electrolyte complexes 3-1 to 3-4 containing the above-mentioned nitrate were used instead of lithium nitrate, the cycle characteristics were further improved compared to when nitrate alone was used. Thus, in this example, even when nitrates other than lithium nitrate are used, the cycle characteristics can be improved compared to the case of no coating or when only nitrate is coated by coating with an electrolyte complex mixed with nitrate and a coordination substance.

[0182] (5) Evaluation based on the amount of electrolyte complex coating As shown in Examples 12 and 13 of Table 5, when the amount of electrolyte complex coated on the separator was increased compared to Example 1, the cycle characteristics improved. Also, as shown in Examples 14 and 15, and 16 and 17 of Table 5, even when VC or DME was used instead of FEC as the coordination substance, increasing the amount of electrolyte complex coated on the separator improved the cycle characteristics compared to Examples 6 and 7. In particular, in Examples 12 to 17, the discharge capacity retention rate at 400 cycles increased significantly compared to Examples 1, 6 and 7. Thus, in this example, the cycle characteristics can be improved by increasing the amount of electrolyte complex coated, which is a mixture of nitrate and coordination substance.

[0183] (6) Evaluation with and without binder As shown in Example 18 of Table 5, when the separator was coated with an electrolyte complex and a binder, the cycle characteristics were improved compared to Comparative Example 14 of Table 10, where nitrate and a binder were coated. In addition, the discharge capacity retention rate at 400 cycles increased compared to Example 1, where no binder was coated. Thus, in this example, coating the separator with an electrolyte complex and a binder can improve cycle characteristics compared to when nitrate and a binder are coated.

[0184] Examples 19 to 24 in Table 5 are modifications of Examples 2 to 7 in which a binder is coated on the separator. Similar to Examples 2 to 7, Examples 19 to 24 also showed improved cycle characteristics compared to Comparative Example 9 in Table 10. In particular, Examples 19 to 24 showed an increased discharge capacity retention rate at 400 cycles compared to Examples 2 to 7. Thus, in this example, cycle characteristics can be improved by coating the electrolyte complex with a binder.

[0185] Examples 25 to 28 in Table 5 are modifications of Examples 8 to 11 in which a binder is coated on the separator. That is, Examples 25 to 28 use lithium nitrate (LiNO2). ３ Instead of ) cesium nitrate (CsNO) ３ ), silver nitrate (AgNO) ３ ), calcium nitrate (Ca(NO) ３ ) ２ ), indium nitrate (In(NO ３ ) ３ A separator coated with an electrolyte complex containing ) and a binder is used. In contrast, Comparative Examples 15 to 18 in Table 10 use lithium nitrate (LiNO). ３ Instead of the above nitrate and binder, a separator coated with the above nitrate and binder is used. Examples 25 to 28 showed improved cycle characteristics compared to Comparative Examples 15 to 18. Thus, in this example, lithium nitrate (LiNO) is used. ３ Even when using nitrates other than those specified above, coating the separator with an electrolyte complex and a binder can improve the cycle characteristics compared to coating it with nitrates and a binder.

[0186] Examples 29 to 34 in Table 5 are modifications of Examples 12 to 17 in which a binder is coated on the separator. Even when a binder is coated on the separator, as in Examples 29 to 34, the cycle characteristics can be improved, as in Examples 12 to 17. In particular, Examples 29 to 34 showed an increased discharge capacity retention rate at 400 cycles compared to Examples 12 to 17. Thus, in this example, by coating the separator with a binder in addition to the electrolyte complex, the discharge capacity retention rate over long cycles can be improved compared to when only the electrolyte complex is coated.

[0187] (7) Evaluation when the electrolyte contains a coordination substance Examples 35 to 68 in Table 6 are modifications of Examples 1 to 34 in Table 5, in which electrolyte 2 is used instead of electrolyte 1. Electrolyte 2 contains fluoroethylene carbonate (FEC), a coordination substance, instead of ethylene carbonate (EC) in electrolyte 1. Examples 35 to 68 in Table 6 show improved cycle characteristics compared to Comparative Examples 2, 19 to 28 in Table 10, which also use electrolyte 2. Thus, in this example, even when the electrolyte further contains a coordination substance, the cycle characteristics can be improved by coating the separator with an electrolyte complex compared to the case where only nitrate is coated.

[0188] (8) Comparative Example 3 in Evaluation Table 10 for the case using a graphite anode is an example in which separator 3-1 without nitrate coating was used and a graphite anode was used instead of a lithium metal anode. In contrast, Comparative Example 29, which used separator 3-2 coated with lithium nitrate as the nitrate, showed higher cycle characteristics than Comparative Example 3. Furthermore, Comparative Example 30, which used separator 3-7 coated with lithium nitrate and binder, also showed higher cycle characteristics than Comparative Example 3. Thus, it can be seen that coating the separator with nitrate improves cycle characteristics even when a graphite anode is used.

[0189] Examples 69 to 71 in Table 7 are modifications using separators 1-1, 1-6, and 1-7 coated with lithium nitrate as the nitrate and electrolyte complexes containing FEC, VC, and DME as coordination substances, respectively, and using a graphite anode instead of a lithium metal anode. All of these examples 69 to 71 showed improved cycle characteristics compared to Comparative Example 29 in Table 10, where the separator was not coated with a coordination substance. Thus, in these examples, even when using a graphite anode, coating the separator with an electrolyte complex can improve cycle characteristics compared to coating the separator with nitrate.

[0190] Examples 75 to 77 in Table 7 are modifications of Examples 69 to 71, in which the separator further includes a binder. In all of these Examples 75 to 77, the cycle characteristics were improved compared to Comparative Example 30 in Table 10, in which the separator was not coated with a coordination substance. Thus, in this example, even when using a graphite anode, coating the separator with an electrolyte complex and a binder can improve the cycle characteristics compared to coating the separator with nitrate and a binder.

[0191] Comparative Examples 4, 31, and 32 in Table 10 are examples in which electrolyte 2 is used instead of electrolyte 1 compared to Comparative Examples 3, 29, and 30. It can be seen that even when electrolyte 2 is used, the cycle characteristics are improved by coating the separator with nitrate.

[0192] Examples 72 to 74 in Table 7 are modifications of Examples 69 to 71, using electrolyte 2 instead of electrolyte 1. All of these Examples 72 to 74 showed improved cycle characteristics compared to Comparative Example 31 in Table 10, in which the separator was not coated with a coordination substance. Thus, in this example, even when using a graphite anode and the electrolyte contains a coordination substance, coating the separator with an electrolyte complex can improve cycle characteristics compared to coating the separator with nitrate.

[0193] Examples 78 to 80 in Table 7 are modifications of Examples 75 to 77, using electrolyte 2 instead of electrolyte 1. In all of these Examples 78 to 80, the cycle characteristics were improved compared to Comparative Example 32 in Table 10, in which the separator was not coated with a coordination substance. Thus, in this example, even when using a graphite anode and the electrolyte contains a coordination substance, coating the separator with an electrolyte complex and a binder can improve the cycle characteristics compared to coating the separator with nitrate and a binder.

[0194] (9) Comparative Example 5 in Evaluation Table 10 for Cases Using Silicon Oxide Anodes is an example in which separator 3-1 without nitrate coating was used and a silicon oxide anode was used instead of a lithium metal anode. In contrast, Comparative Example 33, which used separator 3-2 coated with lithium nitrate as the nitrate, showed higher cycle characteristics than Comparative Example 5. Furthermore, Comparative Example 34, which used separator 3-7 coated with lithium nitrate and binder, also showed higher cycle characteristics than Comparative Example 5. Thus, it can be seen that coating the separator with nitrate improves cycle characteristics even when a silicon oxide anode is used.

[0195] Examples 81 to 83 in Table 8 are modifications using separators 1-1, 1-6, and 1-7 coated with lithium nitrate as the nitrate and electrolyte complexes containing FEC, VC, and DME as coordination substances, respectively, and using a silicon oxide anode instead of a lithium metal anode. All of these examples 81 to 83 showed improved cycle characteristics compared to Comparative Example 33 in Table 10, in which no coordination substance was coated on the separator. Thus, in these examples, even when using a silicon oxide anode, coating the separator with an electrolyte complex can improve cycle characteristics compared to coating the separator with nitrate.

[0196] Examples 87 to 89 in Table 8 are modifications of Examples 81 to 83, in which the separator further includes a binder. In all of these Examples 87 to 89, the cycle characteristics were improved compared to Comparative Example 34 in Table 10, in which the separator was not coated with a coordination substance. Thus, in this example, even when using a silicon oxide anode, coating the separator with an electrolyte complex and a binder can improve the cycle characteristics compared to coating the separator with nitrate and a binder.

[0197] Comparative Examples 6, 35, and 36 in Table 10 are examples in which electrolyte 2 is used instead of electrolyte 1 compared to Comparative Examples 5, 33, and 34. It can be seen that even when electrolyte 2 is used, the cycle characteristics are improved by coating the separator with nitrate.

[0198] Examples 84 to 86 in Table 8 are modifications of Examples 81 to 83, using electrolyte 2 instead of electrolyte 1. In all of these Examples 84 to 86, the cycle characteristics were improved compared to Comparative Example 35 in Table 10, in which the separator was not coated with a coordination substance. Thus, in this example, when using a silicon oxide anode, even when the electrolyte contains a coordination substance, coating the separator with an electrolyte complex can improve the cycle characteristics compared to coating the separator with nitrate.

[0199] Examples 90 to 92 in Table 8 are modifications of Examples 87 to 89, using electrolyte 2 instead of electrolyte 1. All of these Examples 90 to 92 showed improved cycle characteristics compared to Comparative Example 36 in Table 10, in which the separator was not coated with a coordination substance. Thus, in this example, when using a silicon oxide anode, even when the electrolyte contains a coordination substance, coating the separator with an electrolyte complex and a binder can improve cycle characteristics compared to coating the separator with nitrate and a binder.

[0200] (10) Comparative Example 7 in Evaluation Table 10 for Cases Using a Silicon Anode is an example in which a separator 3-1 without nitrate coating was used and a silicon anode was used instead of a lithium metal anode. In contrast, Comparative Example 37, which used a separator 3-2 coated with lithium nitrate as the nitrate, showed higher cycle characteristics than Comparative Example 7. Furthermore, Comparative Example 38, which used a separator 3-7 coated with lithium nitrate and binder, also showed higher cycle characteristics than Comparative Example 7. Thus, it can be seen that coating the separator with nitrate improves cycle characteristics even when a silicon anode is used.

[0201] Examples 93 to 95 in Table 9 are modifications using separators 1-1, 1-6, and 1-7 coated with electrolyte complexes containing lithium nitrate as the nitrate and FEC, VC, and DME as coordination substances, respectively, and using a silicon anode instead of a lithium metal anode. All of these examples 93 to 95 showed improved cycle characteristics compared to Comparative Example 37 in Table 10, in which the separator was not coated with a coordination substance. Thus, in these examples, even when using a silicon anode, coating the separator with an electrolyte complex can improve cycle characteristics compared to when the separator is coated with nitrate.

[0202] Examples 99 to 101 in Table 9 are modifications of Examples 93 to 95, in which the separator further includes a binder. All of these Examples 99 to 101 showed improved cycle characteristics compared to Comparative Example 38 in Table 10, in which the separator was not coated with a coordination substance. Thus, in this example, even when using a silicon anode, coating the separator with an electrolyte complex and a binder can improve cycle characteristics compared to coating the separator with nitrate and a binder.

[0203] Comparative Examples 8, 39, and 40 in Table 10 are examples in which electrolyte 2 is used instead of electrolyte 1 compared to Comparative Examples 7, 37, and 38. It can be seen that even when electrolyte 2 is used, the cycle characteristics are improved by coating the separator with nitrate.

[0204] Examples 96 to 98 in Table 9 are modifications of Examples 93 to 95, using electrolyte 2 instead of electrolyte 1. All of these Examples 96 to 98 showed improved cycle characteristics compared to Comparative Example 39 in Table 10, in which the separator was not coated with a coordination substance. Thus, in this example, even when using a silicon negative electrode and the electrolyte contains a coordination substance, coating the separator with an electrolyte complex can improve cycle characteristics compared to coating the separator with nitrate.

[0205] Examples 102 to 104 in Table 9 are modifications of Examples 99 to 101, using electrolyte 2 instead of electrolyte 1. All of these Examples 102 to 104 showed improved cycle characteristics compared to Comparative Example 40 in Table 10, in which the separator was not coated with a coordination substance. Thus, in this example, even when using a silicon negative electrode and the electrolyte contains a coordination substance, coating the separator with an electrolyte complex and a binder can improve cycle characteristics compared to coating the separator with nitrate and a binder.

[0206] (11) Comparing Examples 1 to 104 and Comparative Examples 1 to 40 described in Summary Tables 5 to 10, it can be seen that the test pouch cell according to this embodiment has a complex-containing layer containing an electrolyte complex with nitrate and a coordination substance in the separator, resulting in superior cycle characteristics compared to the test pouch cells of Comparative Examples 1 to 40 in which the separator does not contain a coordination substance. Furthermore, it can be seen that the cycle characteristics are further improved when a binder is included in addition to the electrolyte complex, or when the electrolyte contains a coordination substance.

[0207] Although the present invention has been described above using embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be apparent to those skilled in the art that various modifications or improvements can be made to the above embodiments. It will be clear from the claims that such modified or improved forms may also be included in the technical scope of the present invention.

[0208] It should be noted that the execution order of operations, procedures, steps, and stages in the devices, systems, programs, and methods shown in the claims, specifications, and drawings is not explicitly stated as "before," "prior to," etc., and that these can be performed in any order unless the output of a previous process is used in a later process. Even if the operation flow in the claims, specifications, and drawings is described using phrases such as "first," "next," etc. for convenience, this does not mean that it is mandatory to perform the operations in that order.

[0209] 100...Battery, 110...Electrode structure, 120...Positive electrode, 122...Positive electrode tab, 130...Separator, 132...First main surface, 134...Second main surface, 135...Complex-containing layer, 140...Negative electrode, 142...Negative electrode tab, 150...Electrolyte, 160...Battery case, 162...Positive electrode terminal, 164...Negative electrode terminal, 172...Positive electrode lead, 174...Negative electrode lead 220... Positive electrode current collector, 222... First main surface, 224... Second main surface, 226... Side surface, 240... Positive electrode active material layer, 320... Negative electrode current collector, 322... First main surface, 324... Second main surface Surface, 326... Side surface, 340... Negative electrode active material layer, 342... First main surface, 344... Second main surface, 346... Side surface, 440... Base material layer, 450... Battery structure, 510... Electrode structure

Claims

1. A separator for use in a secondary battery, comprising a complex-containing layer comprising an electrolyte complex, provided on the surface in contact with the negative electrode of the secondary battery, wherein the electrolyte complex comprises a nitrate and a coordination substance.

2. The electrolyte complex has a peak in the IR spectrum at 1350 cm⁻¹. －１ Above, 1395cm －１ The separator according to claim 1, having the following range:

3. The separator according to claim 1, wherein the electrolyte complex has an ionic conductivity of 1E-7 S / cm or more and 1E-3 S / cm or less.

4. The separator according to claim 1, wherein the electrolyte complex has an ionic conductivity of 1E-5S / cm or more and 1E-3S / cm or less.

5. The separator according to claim 1, wherein the amount of substance of the coordination substance contained in the electrolyte complex is 2% or more and 500% or less of the amount of substance of the nitrate contained in the electrolyte complex.

6. The separator according to claim 1, wherein the coordinating substance comprises one or more substructures selected from carbonyl groups, carboxyl groups, sulfinyl groups, sulfonyl groups, sulfides, ethers, esters, carbonate esters, amides, imides, phosphate esters, phosphine oxides, silyl groups, and borate esters.

7. The separator according to claim 1, wherein the coordinating substance includes a structure obtained by radical polymerization of a monomer having a double bond or a triple bond.

8. The basis density of the electrolyte complex in the complex-containing layer is 0.01 g / cm³. ３ Above, 3.0g / cm ３ The separator according to claim 1, which is as follows:

9. The surface density of the electrolyte complex in the complex-containing layer is 0.01 mg / cm². ２ Above, 100mg / cm ２ The separator according to claim 1, which is as follows:

10. The separator according to claim 1, wherein the particle size of the electrolyte complex in the complex-containing layer is 0.01 μm or more and 10 μm or less.

11. The separator according to claim 1, wherein the thickness of the complex-containing layer is 0.01 μm or more and 20 μm or less.

12. The separator according to any one of claims 1 to 11, wherein the nitrate comprises at least one selected from lithium nitrate, potassium nitrate, cesium nitrate, sodium nitrate, silver nitrate, calcium nitrate, zinc nitrate, copper nitrate, magnesium nitrate, indium nitrate, aluminum nitrate, ammonium nitrate, barium nitrate, and iron nitrate.

13. The separator according to any one of claims 1 to 11, wherein the coordinating substance comprises at least one selected from fluoroethylene carbonate, vinylene carbonate 1,2-dimethoxyethane, polyethylene oxide, carbonylmethylcellulose, polyimide, polyamide, polyimideamide, polysiloxane, and polycarbonate.

14. A separator according to any one of claims 1 to 11, comprising a binder for supporting the electrolyte complex on the separator, wherein the mass of the binder is 0.5% or more and 30% or less of the mass of the electrolyte complex.

15. The separator according to claim 14, wherein the binder is at least one selected from polyvinylidene fluoride, acrylic latex, acrylic resin, polyacrylic acid-styrene copolymer, styrene-butadiene rubber, polyvinyl alcohol, epoxy resin, sodium polyacrylate, polytetrafluoroethylene, polysiloxane, polyoxyethylene-methylpolysiloxane copolymer, polyimide, polyamide, polyamideimide, polyester, carboxymethylcellulose, cellulose derivatives, and polysulfone.

16. A separator according to any one of claims 1 to 11, comprising fibers for supporting the electrolyte complex on the separator, wherein the mass of the fibers is 0.5% or more and 30% or less of the mass of the electrolyte complex.

17. The separator according to claim 16, wherein the fiber is at least one selected from hollow fibers, nanofibers, porous polymer fibers, and cellulose fibers.

18. A battery structure comprising the separator described in claim 1 and a negative electrode in contact with the complex-containing layer.

19. The battery structure according to claim 18, wherein the negative electrode is selected from a lithium metal negative electrode, a graphite negative electrode, a silicon oxide negative electrode, and a silicon negative electrode.

20. A secondary battery comprising the battery structure described in claim 18, a positive electrode disposed at a distance from the negative electrode, and a non-aqueous electrolyte.

21. The secondary battery according to claim 20, wherein the secondary battery further comprises the coordination substance in the non-aqueous electrolyte.

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