Lithium ion conductor, lithium ion battery, and method for producing lithium ion conductor

Abstract

To provide a technique that can suppress deterioration of charging / discharging characteristics as much as possible when cracking has occurred in an electrolyte layer or an electrode in a lithium ion battery.SOLUTION: An electrolyte layer or an electrode of a lithium ion battery is allowed to contain a prescribed lithium ion conductor. The inventive lithium ion conductor contains a composite halogen compound represented by LiGaX4 (where X is one or more halogen).SELECTED DRAWING: None

Description

[Technical field]

[0001] The present application discloses a lithium ion conductor, a lithium ion battery, and a method for making the lithium ion conductor. [Background technology]

[0002] Patent Document 1 discloses an anode layer of an all-solid-state lithium-ion battery, which has particles of an alloy-based active material, and the particles of the alloy-based active material are twin crystal particles having two or more crystal orientations within one particle. In Patent Document 1, it is said that by using twin crystal particles as particles of the alloy-based active material, stress generated inside the anode layer is released to the twin crystal particles, and cracks inside the anode layer can be suppressed. Patent Document 2 discloses a solid electrolyte constituting a solid electrolyte layer of an all-solid-state lithium-ion battery, which includes a lithium salt, a sulfide solid electrolyte, and an organic electrolyte having a predetermined elastic modulus ratio. The organic electrolyte disclosed in Patent Document 2 has a property that the ratio of the storage elastic modulus to the loss elastic modulus decreases to less than 1 when heated. In Patent Document 2, by heating a solid electrolyte layer including a lithium salt, a sulfide solid electrolyte, and an organic electrolyte, the organic electrolyte changes from a solid behavior to a liquid behavior as the temperature increases, and the organic electrolyte becomes compatible with the sulfide solid electrolyte, thereby improving ion conductivity. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-092100 A [Patent Document 2] JP 2020-198270 A Summary of the Invention [Problem to be solved by the invention]

[0004] Even if the crystal orientation of the active material particles is adjusted, it is difficult to completely suppress cracking of the electrolyte layer and electrodes that accompany charging and discharging of a lithium-ion battery. The cracking of the electrolyte layer and electrodes in a lithium-ion battery may deteriorate the charging and discharging characteristics of the lithium-ion battery. In a lithium-ion battery, a technology is required that can suppress the deterioration of the charging and discharging characteristics as much as possible when the electrolyte layer or electrodes are cracked. [Means for solving the problem]

[0005] The present application discloses the following aspects as means for solving the above problems. <Aspect 1> A lithium ion conductor comprising a complex halide represented by LiGaX4 (wherein X is one or more halogens). <Aspect 2> The complex halide contains a plurality of the halogens. The lithium ion conductor of embodiment 1. <Aspect 3> The complex halide includes at least one of Br and Cl. The lithium ion conductor of embodiment 1 or 2. <Aspect 4> the complex halide comprises Br and I; The lithium ion conductor according to any one of embodiments 1 to 3. <Aspect 5> A lithium ion battery having a positive electrode, an electrolyte layer, and a negative electrode, At least one of the positive electrode, the electrolyte layer, and the negative electrode contains the lithium ion conductor according to any one of aspects 1 to 4. Lithium-ion battery. <Aspect 6> At least one of the positive electrode, the electrolyte layer, and the negative electrode contains the lithium ion conductor and a sulfide solid electrolyte. The lithium ion battery of embodiment 5. <Aspect 7> A method for producing a lithium ion conductive material, comprising the steps of: mixing at least one lithium halide with at least one gallium halide to obtain a complex halide represented by LiGaX4, where X is one or more halogens; Manufacturing method. Effect of the Invention

[0006] The lithium ion conductor of the present disclosure is soft and has a property that ion conductivity increases under pressure, and can cause a reaction such as a sintering reaction even at a low temperature such as room temperature. By including such a lithium ion conductor in at least one of the electrode and electrolyte layer of a lithium ion battery, even if a crack occurs in the electrode or electrolyte layer, the interface of the crack is repaired by the lithium ion conductor, and the lithium ion conduction path is unlikely to be interrupted. In other words, a lithium ion battery including the lithium ion conductor of the present disclosure is likely to maintain its charge and discharge characteristics even if a crack occurs in the electrolyte layer or electrode. [Brief description of the drawings]

[0007] [Figure 1] 1 shows a schematic configuration of a lithium-ion battery. [Diagram 2] The X-ray diffraction peaks of LiGaCl4 are shown. [Diagram 3] 1 shows the time dependence of ionic conductivity of a pellet cell under pressure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] 1. Lithium ion conductor The lithium ion conductors of the present disclosure include complex halides represented by LiGaX4, where X is one or more halogens.

[0009] 1.1 Complex halides represented by LiGaX4 According to the inventor's new findings, the complex halide represented by LiGaX4 has a property that the "room temperature sintering mechanism" in which the interface resistance disappears or decreases even at room temperature under pressure works, and the ionic conductivity gradually improves. On the other hand, when the lithium ion conductor is applied to various electrochemical devices, the lithium ion conductor may be in a state of being pressurized to a certain extent. Therefore, the lithium ion conductor of the present disclosure is likely to exhibit high ionic conductivity in various electrochemical devices. In addition, since the complex halide is relatively soft, it can follow the deformation of the surrounding material. In other words, the gaps generated by the deformation or cracking of the material are filled by the lithium ion conductor of the present disclosure, and the ionic conduction path is unlikely to be interrupted.

[0010] Whether or not the lithium ion conductor contains a complex halide represented by LiGaX4 can be confirmed by X-ray diffraction or the like. That is, when an X-ray diffraction peak is obtained from the lithium ion conductor of the present disclosure using CuKα as a radiation source, the X-ray diffraction peak contains a diffraction peak derived from LiGaX4. As far as the present inventors have confirmed, the diffraction peak derived from LiGaX4 differs depending on the type of X, but for example, the diffraction peak derived from LiGaCl4 appears at 15.3°±0.5°, 18.1°±0.5°, 18.7°±0.5°, 19.4°±0.5°, and 27.5°±0.5°.

[0011] In the composite halide represented by LiGaX4, X is one or more halogens, and may be, for example, at least one selected from the group consisting of Cl, Br, and I. According to the new findings of the present inventors, when the composite halide has one or more of the following configurations (1) to (3), the rate of increase in ion conductivity when maintained under pressure tends to be particularly large, and the composite halide tends to be more preferable as a lithium ion conductor. (1) The above complex halide contains multiple types of halogens. (2) The complex halide contains at least one of Br and Cl. (3) The above complex halides contain Br and I.

[0012] According to the findings of the present inventors, when a composite halide contains Br as a halogen, the increase rate of ionic conductivity when maintained under pressure is likely to be even greater by containing at least one of Cl and I together with the Br. In this case, there is no particular limitation on the molar ratio of Cl or I to Br, and high ionic conductivity can be ensured regardless of the molar ratio. In addition, when a composite halide contains Cl and I as halogens, the increase rate of ionic conductivity when maintained under pressure is likely to be particularly high if the molar ratio of Cl to the total of Cl and I is 50 mol % or more.

[0013] In the lithium ion conductor of the present disclosure, the above-mentioned composite halide may have a crystal structure made of a plurality of kinds of LiGaX4, or may have a eutectic structure made of a plurality of kinds of LiGaX4. That is, in the above-mentioned composite halide, a plurality of kinds of LiGaX4 may be solid-dissolved or substituted with each other, and may have a structure or structure different from the structure or structure of each alone. The above-mentioned composite halide may have a eutectic structure of LiGaBr4 and LiGaCl4, a eutectic structure of LiGaBr4 and LiGaI4, a eutectic structure of LiGaCl4 and LiGaI4, or a eutectic structure of LiGaBr4, LiGaCl4 and LiGaI4. The ratio of the plurality of kinds of LiGaX4 is not particularly limited. For example, when the complex halide has a first complex halide represented by LiGaXa4 (wherein Xa is one of Br, Cl, and I) and a second complex halide represented by LiGaXb4 (wherein Xb is a halogen different from Xa and is one of Br, Cl, and I), the molar ratio of the first complex halide to the second complex halide (first complex halide / second complex halide) may be 1 / 4 or more and 4 or less, 3 / 7 or more and 7 / 3 or less, or 2 / 3 or more and 3 / 2 or less.

[0014] 1.2 Components other than complex halides represented by LiGaX4 The lithium ion conductor of the present disclosure may contain other halides in addition to the complex halide represented by LiGaX4. For example, it may contain LiX, GaX2, GaX3, LiGaX3, etc. That is, the lithium ion conductor of the present disclosure does not necessarily have to contain Li, Ga, and X in a molar ratio of 1:1:4 as the entire chemical composition. In addition, it is considered that the complex halide constituting the lithium ion conductor of the present disclosure can also be eutecticized with other lithium compounds, and in that case, it is considered that the same effect is exhibited. For example, it is considered that it is possible to soften the inorganic lithium compound or improve the lithium ion conductivity under pressure by forming a eutectic mixture with at least one inorganic lithium compound selected from B-based lithium salts, Al-based lithium salts, In-based lithium salts, other halogen-based lithium salts such as LiPF6 and LiBF4, hydride-based lithium salts such as LiBH4 and LiCBH, lithium sulfides such as Li3PS4 and LPSI, lithium oxides such as LLZO, LPO, and LLTO, and other inorganic lithium compounds such as nitrates, hydroxides, sulfates, and carbonates, with the above-mentioned composite halides. Alternatively, it is also possible to combine the above-mentioned composite halides with organic lithium salts such as amide salts or imide salts such as LiTFSA (LiTFSI, lithium bistrifluoromethanesulfonylimide), LiBETI (lithium bispentafluoroethanesulfonylimide), LiFSA (LiFSI, lithium bisfluorosulfonylimide), and LiFTA (LiFTI, lithium fluorosulfonyl(trifluoromethanesulfonyl)imide). In this manner, the lithium ion conductor of the present disclosure may be composed only of the above-mentioned complex halide, or may be a combination of the above-mentioned complex halide with other lithium compounds, etc.

[0015] The lithium ion conductor of the present disclosure may be a combination of the above composite halide and a solid electrolyte. The solid electrolyte may be any solid electrolyte used in a battery. The solid electrolyte may be a sulfide solid electrolyte containing at least Li and S as constituent elements. In particular, sulfide solid electrolytes containing at least Li, S, and P as constituent elements have high performance, and sulfide solid electrolytes based on a Li3PS4 skeleton and containing at least one halogen are also high in performance. Examples of sulfide solid electrolytes include Li2S-P2S5, Li2S-SiS2, LiI-Li2S-SiS2, LiI-Si2S-P2S5, Li2S-P2S5-LiI-LiBr, LiI-Li2S-P2S5, LiI-Li2S-P2O5, LiI-Li3PO4-P2S5, Li2S-P2S5-GeS2, and the like. The sulfide solid electrolyte may be amorphous or crystalline. The sulfide solid electrolyte may be, for example, in the form of particles. The sulfide solid electrolyte may be used alone or in combination of two or more kinds.

[0016] When the lithium ion conductor of the present disclosure includes a sulfide solid electrolyte together with the composite halide, the mass ratio of the sulfide solid electrolyte to the composite halide is not particularly limited. For example, the total of the sulfide solid electrolyte and the composite halide is taken as 100 mass%, and the ratio of the sulfide solid electrolyte may be 40 mass% or more and less than 100 mass%, 50 mass% or more and less than 100 mass%, 60 mass% or more and less than 100 mass%, 70 mass% or more and less than 100 mass%, or 80 mass% or more and less than 100 mass%, and the ratio of the composite halide may be more than 0 mass% and less than 60 mass%, more than 0 mass% and less than 50 mass%, more than 0 mass% and less than 40 mass%, more than 0 mass% and less than 30 mass%, or more than 0 mass% and less than 20 mass%.

[0017] When the lithium ion conductor of the present disclosure is used as an electrochemical device material, the above-mentioned complex halide, any solid electrolyte, and other components may be combined. The other components may be appropriately determined according to the specific application of the lithium ion conductor. For example, when the lithium ion conductor is used as an electrode material of a lithium ion battery, the lithium ion conductor may be combined with an active material, a conductive assistant, a binder, and the like. When the lithium ion conductor is used as a material constituting an electrolyte layer of a lithium ion battery, the lithium ion conductor may be combined with a binder, and the like. The lithium ion conductor may contain the above-mentioned complex halide, any solid electrolyte, and other electrolytes (solid electrolytes other than sulfide solid electrolytes or liquid electrolytes). Furthermore, the lithium ion conductor of the present disclosure may contain various additives.

[0018] 2. Lithium-ion battery The lithium ion conductor of the present disclosure can be applied, for example, as a lithium ion conductive material in a lithium ion battery. As shown in FIG. 1, a lithium ion battery 100 according to an embodiment has a positive electrode 10, an electrolyte layer 20, and an anode 30. Here, at least one of the positive electrode 10, the electrolyte layer 20, and the anode 30 includes the lithium ion conductor of the present disclosure. As described above, the complex halide constituting the lithium ion conductor of the present disclosure is soft, and the ion conductivity gradually improves when a pressurized state is maintained. Therefore, for example, during the manufacture of the battery, the complex halide deforms and fills the gaps in the electrodes and electrolyte layer, so that the filling rate in the electrodes and electrolyte layer is likely to increase. In addition, even if cracks or peeling occur in the electrodes or electrolyte layer during use of the battery, the complex halide fills the cracked or peeled part, thereby eliminating the gaps caused by the cracks or peeling, and the ion conduction path is less likely to be interrupted. In addition, the lithium ion conductor of the present disclosure is likely to be pressurized inside the lithium ion battery, and is likely to exhibit excellent lithium ion conductivity. Furthermore, by using the lithium ion conductor of the present disclosure in combination with a lithium ion battery using lithium metal, it is expected that the generation of dendrites can be suppressed. In this way, by including the lithium ion conductor of the present disclosure in at least one of the positive electrode 10, the electrolyte layer 20, and the negative electrode 30 of the lithium ion battery 100, the performance of the lithium ion battery 100 is likely to be improved.

[0019] In the lithium ion battery 100, a solid electrolyte, other liquid electrolytes, or liquid additives may be used in combination with the lithium ion conductor of the present disclosure. The lithium ion battery 100 may be, for example, an all-solid-state battery that does not contain liquid, or may contain a solid electrolyte and a liquid. In particular, in the lithium ion battery 100, when at least one of the positive electrode 10, the electrolyte layer 20, and the negative electrode 30 contains the lithium ion conductor of the present disclosure and a solid electrolyte (particularly a sulfide solid electrolyte), the lithium ion conductor of the present disclosure can follow the deformation or cracking of the solid electrolyte, and even if a gap occurs due to the deformation or cracking of the sulfide solid electrolyte, the lithium ion conductor of the present disclosure can fill the gap, thereby suppressing interruption of the ion conduction path, etc.

[0020] 2.1 Positive electrode As shown in FIG. 1, a positive electrode 10 according to one embodiment may include a positive electrode active material layer 11 and a positive electrode current collector 12. In this case, the positive electrode active material layer 11 may contain the above-mentioned lithium ion conductor.

[0021] 2.1.1 Cathode active material layer The positive electrode active material layer 11 includes a positive electrode active material, and may further include an electrolyte, a conductive assistant, a binder, and the like. Furthermore, the positive electrode active material layer 11 may further include various additives. When the positive electrode active material layer 11 includes the lithium ion conductor of the present disclosure as an electrolyte, the positive electrode active material layer 11 includes a positive electrode active material in addition to the lithium ion conductor, and may further include other electrolytes, conductive assistants, binders, and various additives. The content of each of the positive electrode active material, electrolyte, conductive assistant, binder, and the like in the positive electrode active material layer 11 may be appropriately determined according to the intended battery performance. For example, the content of the positive electrode active material may be 40% by mass or more, 50% by mass or more, or 60% by mass or more, or less than 100% by mass or 90% by mass or less, with the entire positive electrode active material layer 11 (total solid content) being 100% by mass. The shape of the positive electrode active material layer 11 is not particularly limited, and may be, for example, a sheet having a substantially flat surface. The thickness of the positive electrode active material layer 11 is not particularly limited, and may be, for example, 0.1 μm or more, 1 μm or more, 10 μm or more, or 30 μm or more, and may be 2 mm or less, 1 mm or less, 500 μm or less, or 100 μm or less.

[0022] The positive electrode active material may be a known positive electrode active material for lithium ion batteries. Among known active materials, a material that exhibits a potential (charge / discharge potential) for absorbing and releasing lithium ions that is higher than that of the negative electrode active material described below can be used as the positive electrode active material. As the positive electrode active material, various lithium-containing composite oxides such as lithium cobalt oxide, lithium nickel oxide, lithium manganate, lithium manganese nickel cobalt oxide, and spinel-based lithium compounds may be used, or oxide-based active materials other than lithium-containing composite oxides may be used, or sulfur-based active materials such as elemental sulfur and sulfur compounds may be used. Only one type of positive electrode active material may be used alone, or two or more types may be used in combination. The positive electrode active material may be, for example, particulate, and the size is not particularly limited. The particles of the positive electrode active material may be solid particles, hollow particles, or particles having voids. The particles of the positive electrode active material may be primary particles, or secondary particles in which a plurality of primary particles are aggregated. The average particle diameter (D50) of the particles of the positive electrode active material may be, for example, 1 nm or more, 5 nm or more, or 10 nm or more, and may be 500 μm or less, 100 μm or less, 50 μm or less, or 30 μm or less. Note that the average particle diameter D50 referred to in this application is the particle diameter (median diameter) at an integrated value of 50% in a volume-based particle size distribution obtained by a laser diffraction / scattering method.

[0023] The surface of the positive electrode active material may be covered with a protective layer containing an ion-conductive oxide. That is, the positive electrode active material layer 11 may contain a composite having the above-mentioned positive electrode active material and a protective layer provided on the surface thereof. This makes it easier to suppress the reaction between the positive electrode active material and a sulfide (for example, the above-mentioned sulfide solid electrolyte, etc.). When the battery is a lithium ion battery, examples of the ion-conductive oxide that covers and protects the surface of the positive electrode active material include Li3BO3, LiBO2, Li2CO3, LiAlO2, Li4SiO4, Li2SiO3, Li3PO4, Li2SO4, Li2TiO3, Li4Ti5O 12, Li2Ti2O5, Li2ZrO3, LiNbO3, Li2MoO4, and Li2WO4. The coverage (area ratio) of the protective layer may be, for example, 70% or more, 80% or more, or 90% or more. The thickness of the protective layer may be, for example, 0.1 nm or more or 1 nm or more, and may be 100 nm or less, or 20 nm or less.

[0024] The electrolyte that can be contained in the positive electrode active material layer 11 may be a solid electrolyte, a liquid electrolyte (electrolytic solution), or a combination thereof.

[0025] The solid electrolyte may be any known solid electrolyte for lithium ion batteries. The solid electrolyte may be an inorganic solid electrolyte or an organic polymer electrolyte. In particular, inorganic solid electrolytes are excellent in ion conductivity and heat resistance. In addition to the above-mentioned sulfide solid electrolytes, examples of inorganic solid electrolytes include lithium lanthanum zirconate, LiPON, Li 1+X Al X Ge 2-X Examples of oxide solid electrolytes include (PO4)3, Li-SiO-based glass, and Li-Al-SO-based glass. In particular, sulfide solid electrolytes, particularly sulfide solid electrolytes containing at least Li, S, and P as constituent elements, have high performance. When the positive electrode active material layer 11 contains a solid electrolyte (particularly, a sulfide solid electrolyte) together with the lithium ion conductor of the present disclosure, the effect of repairing cracks in the solid electrolyte by the lithium ion conductor of the present disclosure can be expected. The solid electrolyte may be amorphous or crystalline. The solid electrolyte may be, for example, particulate. Only one type of solid electrolyte may be used alone, or two or more types may be used in combination.

[0026] The electrolyte may contain, for example, lithium ions as carrier ions. The electrolyte may be, for example, a non-aqueous electrolyte. For example, the electrolyte may be a carbonate-based solvent in which a lithium salt is dissolved at a predetermined concentration. Examples of the carbonate-based solvent include fluoroethylene carbonate (FEC), ethylene carbonate (EC), and dimethyl carbonate (DMC). Examples of the lithium salt include hexafluorophosphate.

[0027] Examples of the conductive assistant that may be included in the positive electrode active material layer 11 include carbon materials such as vapor grown carbon fiber (VGCF), acetylene black (AB), ketjen black (KB), carbon nanotubes (CNT), and carbon nanofibers (CNF); and metal materials such as nickel, aluminum, and stainless steel. The conductive assistant may be, for example, particulate or fibrous, and the size is not particularly limited. Only one type of conductive assistant may be used alone, or two or more types may be used in combination.

[0028] Examples of binders that can be included in the positive electrode active material layer 11 include butadiene rubber (BR)-based binders, butylene rubber (IIR)-based binders, acrylate butadiene rubber (ABR)-based binders, styrene butadiene rubber (SBR)-based binders, polyvinylidene fluoride (PVdF)-based binders, polytetrafluoroethylene (PTFE)-based binders, polyimide (PI)-based binders, polyacrylic acid-based binders, etc. Only one type of binder may be used alone, or two or more types may be used in combination.

[0029] 2.1.2 Positive electrode current collector As shown in FIG. 1, the positive electrode 10 may include a positive electrode collector 12 in contact with the positive electrode active material layer 11. The positive electrode collector 12 may be any of those commonly used as a positive electrode collector for a battery. The positive electrode collector 12 may be in the form of a foil, a plate, a mesh, a punched metal, a foam, or the like. The positive electrode collector 12 may be made of a metal foil or a metal mesh. In particular, a metal foil is excellent in terms of ease of handling. The positive electrode collector 12 may be made of a plurality of foils. Examples of metals constituting the positive electrode collector 12 include Cu, Ni, Cr, Au, Pt, Ag, Al, Fe, Ti, Zn, Co, stainless steel, and the like. In particular, from the viewpoint of ensuring oxidation resistance, the positive electrode collector 12 may contain Al. The positive electrode collector 12 may have some kind of coating layer on its surface for the purpose of adjusting resistance, or the like. The positive electrode current collector 12 may be a metal foil or a substrate plated or vapor-deposited with the above metal. When the positive electrode current collector 12 is made of a plurality of metal foils, some layer may be present between the plurality of metal foils. The thickness of the positive electrode current collector 12 is not particularly limited. For example, it may be 0.1 μm or more or 1 μm or more, and may be 1 mm or less or 100 μm or less.

[0030] In addition to the above configuration, the positive electrode 10 may have a general configuration as a positive electrode of a lithium ion battery. For example, a tab, a terminal, etc. The positive electrode 10 can be manufactured by applying a known method. For example, the positive electrode active material layer 11 can be easily formed by forming a positive electrode mixture containing the above various components in a dry or wet manner. The positive electrode active material layer 11 may be formed together with the positive electrode current collector 12, or may be formed separately from the positive electrode current collector 12.

[0031] 2.2 Electrolyte layer The electrolyte layer 20 includes at least an electrolyte. The electrolyte layer 20 may include a solid electrolyte, and may further include a binder or the like. When the electrolyte layer 20 includes the lithium ion conductor of the present disclosure as an electrolyte, the electrolyte layer 20 may further include other electrolytes, binders, and various additives in addition to the lithium ion conductor. In this case, the content of the electrolyte and binders in the electrolyte layer 20 is not particularly limited. Alternatively, the electrolyte layer 20 may include an electrolytic solution, and may further include a separator or the like for holding the electrolytic solution and preventing contact between the positive electrode active material layer 11 and the negative electrode active material layer 31. The thickness of the electrolyte layer 20 is not particularly limited, and may be, for example, 0.1 μm or more or 1 μm or more, and may be 2 mm or less or 1 mm or less.

[0032] The electrolyte contained in the electrolyte layer 20 may be appropriately selected from the lithium ion conductor of the present disclosure and the electrolytes exemplified as the electrolytes that may be contained in the positive electrode active material layer. For example, when the electrolyte layer 20 contains a solid electrolyte (particularly, a sulfide solid electrolyte) together with the lithium ion conductor of the present disclosure, the effect of repairing cracks in the solid electrolyte by the lithium ion conductor of the present disclosure can be expected. The binder that may be contained in the electrolyte layer 20 may also be appropriately selected from the binders exemplified as the binders that may be contained in the positive electrode active material layer. Only one type of electrolyte or binder may be used alone, or two or more types may be used in combination. When the lithium ion battery is an electrolyte battery, the separator for holding the electrolyte may be any separator that is commonly used in lithium ion batteries, and examples thereof include separators made of resins such as polyethylene (PE), polypropylene (PP), polyester, and polyamide. The separator may have a single layer structure or a multilayer structure. Examples of the separator having a multi-layer structure include a separator having a two-layer structure of PE / PP, or a separator having a three-layer structure of PP / PE / PP or PE / PP / PE, etc. The separator may be made of a nonwoven fabric such as a cellulose nonwoven fabric, a resin nonwoven fabric, or a glass fiber nonwoven fabric.

[0033] 2.3 Negative electrode As shown in FIG. 1, an anode 30 according to one embodiment may include an anode active material layer 31 and an anode current collector 32. In this case, the anode active material layer 31 may contain the above-mentioned lithium ion conductor.

[0034] 2.3.1 Negative electrode active material layer The negative electrode active material layer 31 includes a negative electrode active material, and may further include an electrolyte, a conductive assistant, a binder, and the like. Furthermore, the negative electrode active material layer 31 may further include various additives. When the negative electrode active material layer 31 includes the lithium ion conductor of the present disclosure as an electrolyte, the negative electrode active material layer 31 includes a negative electrode active material in addition to the lithium ion conductor, and may further include other electrolytes, conductive assistants, binders, and various additives. The contents of the negative electrode active material, electrolyte, conductive assistant, binder, and the like in the negative electrode active material layer 31 may be appropriately determined according to the intended battery performance. For example, the content of the negative electrode active material may be 40% by mass or more, 50% by mass or more, or 60% by mass or more, or may be less than 100% by mass or 90% by mass or less, with the entire negative electrode active material layer 31 (total solid content) being 100% by mass. The shape of the negative electrode active material layer 31 is not particularly limited, and may be, for example, a sheet having a substantially flat surface. The thickness of the negative electrode active material layer 31 is not particularly limited, and may be, for example, 0.1 μm or more, 1 μm or more, 10 μm or more, or 30 μm or more, and may be 2 mm or less, 1 mm or less, 500 μm or less, or 100 μm or less.

[0035] As the negative electrode active material, various materials having a potential (charge / discharge potential) for absorbing and releasing a predetermined ion that is lower than that of the positive electrode active material can be used. For example, silicon-based active materials such as Si, Si alloys, and silicon oxide; carbon-based active materials such as graphite and hard carbon; various oxide-based active materials such as lithium titanate; metallic lithium, lithium alloys, and the like can be used. The negative electrode active material may be used alone or in combination of two or more. The shape of the negative electrode active material may be a general shape as a negative electrode active material for a lithium ion battery. For example, the negative electrode active material may be in a particulate form. The negative electrode active material particles may be primary particles or secondary particles formed by agglomeration of a plurality of primary particles. The average particle diameter (D50) of the negative electrode active material particles may be, for example, 1 nm or more, 5 nm or more, or 10 nm or more, and may be 500 μm or less, 100 μm or less, 50 μm or less, or 30 μm or less. Alternatively, the negative electrode active material may be in the form of a sheet (foil or film) such as lithium foil, etc. In other words, the negative electrode active material layer 31 may be made of a sheet of the negative electrode active material.

[0036] Examples of the electrolyte that can be contained in the negative electrode active material layer 31 include the lithium ion conductor of the present disclosure, the solid electrolyte, the electrolyte solution, or a combination thereof. For example, when the negative electrode active material layer 31 contains a solid electrolyte (particularly, a sulfide solid electrolyte) together with the lithium ion conductor of the present disclosure, the lithium ion conductor of the present disclosure can be expected to have the effect of repairing cracks in the solid electrolyte. Examples of the conductive assistant that can be contained in the negative electrode active material layer 31 include the carbon material and the metal material. The binder that can be contained in the negative electrode active material layer 31 may be appropriately selected from, for example, those exemplified as the binder that can be contained in the positive electrode active material layer 11. The electrolyte and the binder may each be used alone, or two or more types may be used in combination.

[0037] 2.3.2 Negative electrode current collector As shown in FIG. 1, the negative electrode 30 may include a negative electrode current collector 32 in contact with the negative electrode active material layer 31. The negative electrode current collector 32 may be any of those commonly used as a negative electrode current collector for a battery. The negative electrode current collector 32 may be in the form of a foil, a plate, a mesh, a punched metal, a foam, or the like. The negative electrode current collector 32 may be a metal foil or a metal mesh, or may be a carbon sheet. In particular, a metal foil is excellent in terms of ease of handling. The negative electrode current collector 32 may be made of a plurality of foils or sheets. Examples of metals constituting the negative electrode current collector 32 include Cu, Ni, Cr, Au, Pt, Ag, Al, Fe, Ti, Zn, Co, stainless steel, and the like. In particular, from the viewpoint of ensuring reduction resistance and being difficult to alloy with lithium, the negative electrode current collector 32 may contain at least one metal selected from Cu, Ni, and stainless steel. The negative electrode current collector 32 may have some kind of coating layer on its surface for the purpose of adjusting the resistance or the like. The negative electrode current collector 32 may be a metal foil or a base material on which the above metal is plated or vapor-deposited. When the negative electrode current collector 32 is made of a plurality of metal foils, some kind of layer may be present between the plurality of metal foils. The thickness of the negative electrode current collector 32 is not particularly limited. For example, it may be 0.1 μm or more or 1 μm or more, and may be 1 mm or less or 100 μm or less.

[0038] In addition to the above configuration, the negative electrode 30 may have a general configuration as a negative electrode of a lithium ion battery. For example, a tab, a terminal, etc. The negative electrode 30 can be manufactured by applying a known method. For example, the negative electrode active material layer 31 can be easily formed by forming a negative electrode mixture containing the above various components in a dry or wet manner. The negative electrode active material layer 31 may be formed together with the negative electrode current collector 32 or may be formed separately from the negative electrode current collector 32.

[0039] 2.4 Other matters The lithium ion battery 100 may have the above-mentioned components housed inside an exterior body. Any known exterior body for a battery can be used as the exterior body. A plurality of lithium ion batteries 100 may be electrically connected and stacked in any manner to form an assembled battery. In this case, the assembled battery may be housed inside a known battery case. The lithium ion battery 100 may also have other obvious components such as necessary terminals. The shape of the lithium ion battery 100 may be, for example, a coin type, a laminate type, a cylindrical type, a square type, or the like.

[0040] The lithium ion battery 100 can be manufactured by applying a known method. For example, it can be manufactured as follows. However, the manufacturing method of the lithium ion battery 100 is not limited to the following method, and each layer may be formed by, for example, dry molding. (1) The positive electrode active material constituting the positive electrode active material layer is dispersed in a solvent to obtain a positive electrode layer slurry. The solvent used in this case is not particularly limited, and water or various organic solvents can be used. The positive electrode layer slurry is applied to the surface of a positive electrode current collector using a doctor blade or the like, and then dried to form a positive electrode active material layer on the surface of the positive electrode current collector, thereby forming a positive electrode. (2) The negative electrode active material constituting the negative electrode active material layer is dispersed in a solvent to obtain a negative electrode layer slurry. The solvent used in this case is not particularly limited, and water or various organic solvents can be used. The negative electrode layer slurry is applied to the surface of the negative electrode current collector using a doctor blade or the like, and then dried to form a negative electrode active material layer on the surface of the negative electrode current collector, thereby forming a negative electrode. (3) The layers are laminated so that the electrolyte layer (solid electrolyte layer or separator) is sandwiched between the negative electrode and the positive electrode to obtain a laminate having the negative electrode current collector, the negative electrode active material layer, the electrolyte layer, the positive electrode active material layer, and the positive electrode current collector in this order. Other members such as terminals are attached to the laminate as necessary. (4) The laminate is housed in a battery case, and in the case of an electrolyte battery, the battery case is filled with electrolyte, and the laminate is immersed in the electrolyte and sealed in the battery case to produce a lithium ion battery. In the case of a battery containing electrolyte, the electrolyte may be impregnated in the negative electrode active material layer, the separator, and the positive electrode active material layer at the above step (3).

[0041] 3. Manufacturing method of lithium ion conductor The lithium ion conductor of the present disclosure can be produced, for example, by mixing a lithium halide and a gallium halide. Specifically, the method for producing the lithium ion conductor of the present disclosure may include mixing at least one lithium halide and at least one gallium halide to obtain a composite halide represented by LiGaX4 (X is one or more halogens).

[0042] 3.1 Lithium halides The lithium halide may be lithium chloride, lithium bromide, lithium iodide, or a combination thereof. The lithium halide may be in any form that can be mixed with the gallium halide, for example, in particulate form.

[0043] 3.2 Gallium halides The gallium halide may be gallium chloride, gallium bromide, gallium iodide, or a combination thereof. The gallium halide may be in any form that can be mixed with lithium halide, for example, in particulate form. The valence of gallium in the gallium halide may be divalent or trivalent, but high ionic conductivity is easily ensured when it is trivalent. That is, GaX3 (X is one or more halogens) may be used as the gallium halide.

[0044] 3.3 Mixing ratio The mixing ratio of the lithium halide and the gallium halide may be such that LiGaX4 is generated in the lithium ion conductor after mixing. For example, the molar ratio (Li / Ga) of the lithium in the lithium halide and the gallium in the gallium halide may be 0.6 or more and 1.5 or less. The molar ratio may be 0.7 or more, 0.8 or more, or 0.9 or more, and may be 1.4 or less, 1.3 or less, 1.2 or less, or 1.1 or less.

[0045] 3.4 Mixing means The composite halide constituting the lithium ion conductor of the present disclosure can be produced, for example, by mixing the lithium halide and the gallium halide while applying stress to them. The stress may be, for example, frictional force, shear force, shear stress, impact force, etc. Examples of the method of applying such stress during mixing include a method of mixing while pulverizing the materials by a mechanical mixing means such as a ball mill.

[0046] 4. How to Use Lithium Ion Conductors The technology of the present disclosure also has an aspect of a method for using a lithium ion conductor. That is, the method for using a lithium ion conductor of the present disclosure is characterized in that the lithium ion conductor of the present disclosure is used in an electrochemical device while being pressurized. For example, the lithium ion conductor of the present disclosure is used in a pressurized state in at least one of the positive electrode, electrolyte layer, and negative electrode of a lithium ion battery. The magnitude of the pressure applied to the lithium ion conductor is not particularly limited. For example, when the lithium ion conductor is included in a pressurized state in at least one of the positive electrode, electrolyte layer, and negative electrode of a lithium ion battery, the pressure applied to the lithium ion conductor may be 0.1 MPa or more and 100 MPa or less, 1 MPa or more and 50 MPa or less, or 5 MPa or more or 30 MPa or less.

[0047] 5. Method for charging and discharging a lithium-ion battery and method for improving cycle characteristics of a lithium-ion battery When the lithium ion conductor of the present disclosure is contained in at least one of the positive electrode, electrolyte layer, and negative electrode of a lithium ion battery, the charge and discharge cycle characteristics of the lithium ion battery are likely to be improved. That is, the method of charging and discharging a lithium ion battery and the method of improving the cycle characteristics of a lithium ion battery of the present disclosure include repeating charging and discharging the lithium ion battery, the lithium ion battery has a positive electrode, an electrolyte layer, and a negative electrode, at least one of the positive electrode, the electrolyte layer, and the negative electrode includes the lithium ion conductor of the present disclosure, and when a gap occurs in at least one of the positive electrode, the electrolyte layer, and the negative electrode due to charging and discharging of the lithium ion battery, at least a part of the gap is eliminated by the lithium ion conductor of the present disclosure. Here, the "gap" may be one that can occur in at least one of the positive electrode, the electrolyte layer, and the negative electrode due to a volume change of an active material. The "gap" is a concept that includes "cracks" and the like. It is believed that by eliminating at least a portion of the gap with the ionic conductor of the present disclosure (i.e., by filling at least a portion of the gap with the lithium ion conductor of the present disclosure), the ionic conduction paths and conductive paths that were interrupted by the gap can be restored.

[0048] 6. Vehicles with lithium-ion batteries As described above, when the lithium ion conductor of the present disclosure is contained in at least one of the positive electrode, electrolyte layer, and negative electrode of a lithium ion battery, the charge / discharge cycle characteristics of the lithium ion battery can be expected to be improved. A lithium ion battery having such excellent charge / discharge cycle characteristics can be suitably used in at least one vehicle selected from, for example, a hybrid vehicle (HEV), a plug-in hybrid vehicle (PHEV), and an electric vehicle (BEV). That is, the technology of the present disclosure also has an aspect of a vehicle having a lithium ion battery, the lithium ion battery having a positive electrode, an electrolyte layer, and a negative electrode, and at least one of the positive electrode, the electrolyte layer, and the negative electrode containing the lithium ion conductor of the present disclosure. EXAMPLES

[0049] As described above, one embodiment of the lithium ion conductor, lithium ion battery, and method for manufacturing the lithium ion conductor of the present disclosure has been described, but the lithium ion conductor, lithium ion battery, and method for manufacturing the lithium ion conductor of the present disclosure can be modified in various ways other than the above embodiment without departing from the gist of the present disclosure. Hereinafter, the technology of the present disclosure will be described in more detail while showing examples, but the technology of the present disclosure is not limited to the following examples.

[0050] 1. Synthesis of mixed halides as lithium ion conductors 1.1 reference Example 1 LiCl (manufactured by Kojundo Chemical Co., Ltd.) and GaCl3 (manufactured by Tokyo Chemical Industry Co., Ltd.) were weighed out to a molar ratio of 50:50, and placed in a 500 ml ZrO2 pot, with φ5 mm ZrO2 balls added, and 100 g of heptane (manufactured by Kanto Chemical Co., Ltd.) added. The mixture was ground at 300 rpm for 1 hour, and this was repeated 20 times. The mixture was dried to obtain LiGaCl4.

[0051] 1.2 reference Example 2 Except for using LiI (Kojundo Chemical Co., Ltd.) instead of LiCl and GaI3 (Aldrich Co., Ltd.) instead of GaCl3, reference Mixing was carried out in the same manner as in Example 1 to obtain LiGaI4. reference LiGaCl4 synthesized in the same manner as in Example 1 and LiGaI4 were mixed in a molar ratio of 80:20, and the mixture was heated and stirred at a temperature above the melting point to obtain a melt. The resulting melt was cooled to room temperature and crushed in a mortar to obtain the molten salt 80LiGaCl4-20LiGaI4.

[0052] 1.3 reference Example 3 Except for mixing LiGaCl4 and LiGaI4 in a molar ratio of 50:50, reference The same procedure as in Example 2 was used to obtain the molten salt 50LiGaCl4-50LiGaI4.

[0053] 1.4 reference Example 4 Except for using LiBr (manufactured by Kojundo Chemical Co., Ltd.) instead of LiCl and GaBr3 (manufactured by Alpha Corp.) instead of GaCl3, reference Mixing was carried out in the same manner as in Example 1 to synthesize LiGaBr4. reference LiGaCl4 synthesized in the same manner as in Example 1 and LiGaBr4 were mixed in a molar ratio of 80:20, and a molten liquid was obtained by heating and stirring at a temperature above the melting point. The resulting molten liquid was cooled to room temperature and crushed in a mortar to obtain a molten salt, 80LiGaCl4-20LiGaBr4.

[0054] 1.5 reference Example 5 Except for mixing LiGaCl4 and LiGaBr4 in a molar ratio of 50:50, reference The same procedure as in Example 4 was used to obtain the molten salt 50LiGaCl4-50LiGaBr4.

[0055] 1.6 reference Example 6 Except for mixing LiGaCl4 and LiGaBr4 in a molar ratio of 20:80, reference The same procedure as in Example 4 was used to obtain the molten salt 20LiGaCl4-80LiGaBr4.

[0056] 1.7 reference Example 7 Except for using LiBr (manufactured by Kojundo Chemical Co., Ltd.) instead of LiCl and GaBr3 (manufactured by Alpha Corp.) instead of GaCl3, reference Mixing was carried out in the same manner as in Example 1 to obtain LiGaBr4.

[0057] 1.8 Example 8 LiGaBr4 and LiGaI4 were mixed in a molar ratio of 80:20, and the mixture was heated and stirred at a temperature above the melting point to obtain a melt. The resulting melt was cooled to room temperature and crushed in a mortar to obtain the molten salt 80LiGaBr4-20LiGaI4.

[0058] 1.9 Example 9 LiGaBr4 and LiGaI4 were mixed in a molar ratio of 70:30, and heated and stirred at a temperature above the melting point to obtain a melt. The resulting melt was cooled to room temperature and crushed in a mortar to obtain the molten salt 70LiGaBr4-30LiGaI4.

[0059] 1.10 Example 10 LiGaBr4 and LiGaI4 were mixed in a molar ratio of 60:40, and the mixture was heated and stirred at a temperature above the melting point to obtain a melt. The resulting melt was cooled to room temperature and crushed in a mortar to obtain the molten salt 60LiGaBr4-40LiGaI4.

[0060] 1.11 Example 11 LiGaBr4 and LiGaI4 were mixed in a molar ratio of 50:50, and the mixture was heated and stirred at a temperature above the melting point to obtain a melt. The resulting melt was cooled to room temperature and crushed in a mortar to obtain the molten salt 50LiGaBr4-50LiGaI4.

[0061] 1.12 Example 12 LiGaBr4 and LiGaI4 were mixed in a molar ratio of 40:60, and the mixture was heated and stirred at a temperature above the melting point to obtain a melt. The resulting melt was cooled to room temperature and crushed in a mortar to obtain the molten salt 40LiGaBr4-60LiGaI4.

[0062] 1.13 Example 13 LiGaBr4 and LiGaI4 were mixed in a molar ratio of 40:60, and heated and stirred at a temperature above the melting point to obtain a melt. The resulting melt was cooled to room temperature and crushed in a mortar to obtain the molten salt 20LiGaBr4-80LiGaI4.

[0063] 1.14 Comparative Example 1 LiCl and AlCl3 (Wako Pure Chemical Industries, Ltd.) were weighed out to a molar ratio of 50:50, and placed in a 500 ml ZrO2 pot. A φ5 mm ZrO2 ball was placed in the pot, and 100 g of heptane (Kanto Chemical Industries, Ltd.) was placed in the pot. The pot was then ground at 300 rpm for 1 hour, and this was repeated 20 times. The mixture was dried to obtain LiAlCl4.

[0064] 1.15 Comparative Example 2 A Li-PSI-Br type sulfide solid electrolyte was prepared.

[0065] 2. Confirmation of crystal structure Figure 2 shows: reference The X-ray diffraction peaks for LiGaCl4 in Example 1 are shown. As is clear from FIG. 2, in the X-ray diffraction peaks for LiGaCl4 obtained after mixing using a ball mill, the peaks derived from the raw materials LiCl and GaCl3 are substantially not observed (or the peaks are reduced compared to the raw materials), and it can be seen that a crystal phase different from LiCl and GaCl3 has been formed, specifically a crystal phase related to LiGaCl4. Similarly, reference In Example 7, a crystalline phase related to LiGaBr4 was confirmed. reference It was confirmed that each of Examples 2 to 6 and Examples 8 to 13 had a eutectic structure of the complex halide.

[0066] 3. Measurement of ionic conductivity reference Example 1~ 7. Examples 8 to The ionic conductivity of each of the lithium ion conductors of No. 13 and Comparative Examples 1 and 2 was measured. Specifically, 150 mg of the ionic conductor was filled in a cylinder and pressed uniaxially to prepare a pellet cell. This was placed in a desiccator and impedance measurement was performed at 25°C in a thermostatic chamber. The ionic conductivity after pressing was calculated from the obtained resistance value and sample thickness. This pellet cell was left in the thermostatic chamber for a certain period of time, the resistance value at the time when the resistance reduction was saturated was read, and the ionic conductivity after storage was calculated.

[0067] 4. Preparation and evaluation of the evaluation battery 4.1 Applications reference Example 1 4.1.1 Preparation of negative electrode mixture The sulfide solid electrolyte of Comparative Example 2, reference The molten salt of Example 2 was weighed out to give a volume ratio of 80:20 to obtain a mixed electrolyte. Crystalline Si as a negative electrode active material, the mixed electrolyte, and VGCF as a conductive additive were mixed in a mortar to obtain a negative electrode mixture.

[0068] 4.1.2 Preparation of the positive electrode mixture LiNbO3-coated NCM (LiNi 1 / 3 Co 1 / 3 Mn 1 / 3 O2), the sulfide solid electrolyte of Comparative Example 2, and VGCF as a conductive additive were mixed in a mortar to obtain a positive electrode mixture.

[0069] 4.1.3 Cell preparation A 6t press was performed on an alumina cylinder having a diameter of 11.28 mm in which the positive electrode composite, the sulfide solid electrolyte of Comparative Example 2, and the negative electrode composite were layered to obtain a laminate consisting of a positive electrode composite layer / sulfide solid electrolyte layer / negative electrode composite layer. The laminate was restrained at 6 N to produce an all-solid-state battery for evaluation.

[0070] 4.1.4 Charge / discharge cycle test The fabricated all-solid-state battery was subjected to 50 cycles of CCCV charging and discharging at a charge / discharge rate of 1 / 3C at room temperature, and the ratio of the capacity after 50 cycles to the initial capacity was calculated as the "capacity retention rate."

[0071] 4.2 Comparative application example 1 In the negative electrode mixture, reference Except for using LiAlCl4 in Comparative Example 1 instead of the molten salt in Example 2, reference An all-solid-state battery was produced in the same manner as in Example 1, and a charge-discharge cycle test was carried out.

[0072] 4.3 Comparative application example 2 In the negative electrode mixture, the same procedure as in Comparative Example 2 was repeated except that only the sulfide solid electrolyte was used as the electrolyte. referenceAn all-solid-state battery was produced in the same manner as in Example 1, and a charge-discharge cycle test was carried out.

[0073] 5. Evaluation Results In Table 1 below, reference Example 1~ 7. Examples 8 to The types and ionic conductivities of the lithium ion conductors of Comparative Examples 1 and 2 are shown in Table 2 below. reference The results of measuring the capacity retention rate of each of the all-solid-state batteries of Example 1 and Comparative Application Examples 1 and 2 are shown in FIG. reference 1 shows the time dependence of ionic conductivity for the pellet cell of Example 2.

[0074] [Table 1]

[0075] [Table 2]

[0076] The results shown in Tables 1 and 2 and FIG.

[0077] As shown in Table 1, reference Example 1~ 7. Examples 8 to It can be seen that the lithium ion conductor No. 13 gradually improves in ionic conductivity when the pressurized state is maintained even at room temperature (25°C). reference Example 1~ 7. Examples 8 to The lithium ion conductor of 13 is considered to be a material that exhibits a "room-temperature sintering mechanism" in which the interfacial resistance disappears or decreases even at room temperature under pressure. Specifically, reference Example 1~ 7. Examples 8 to The lithium ion conductor according to claim 13 undergoes room temperature sintering when pressed into a pellet cell, the interface resistance gradually disappears, and the ionic conductivity increases. As shown in FIG. 3, when this pellet cell is crushed and pressure molded again to form a pellet cell, the interface resistance disappears and the ionic conductivity increases in the same manner as before crushing. That is, reference Example 1~ 7. Examples 8 toIt can be seen that the lithium ion conductor of 13 can be repeatedly sintered at room temperature by pressure and the interface resistance disappears. reference Example 1~ 7. Examples 8 to The lithium ion conductor according to No. 13 is relatively soft and can follow the deformation of the surrounding material. When such a lithium ion conductor is applied to a lithium ion battery, even if the active material expands and contracts during charging and discharging, causing cracks in the solid electrolyte, the lithium ion conductor is thought to repeatedly repair the cracked interface. As a result, as shown in Table 2, the cycle characteristics of the battery are improved, and a high capacity can be maintained before and after the charge and discharge cycles. Such an effect was not confirmed in Comparative Examples 1 and 2, and it is understood that this is a unique effect of the composite halide of Li and Ga.

[0078] In addition, the above reference Example 1~ 7. Examples 8 to In 13, a lithium ion conductor containing a complex halide represented by LiGaX4 (X is one or more halogens) was applied to the negative electrode of a lithium ion battery, but the lithium ion conductor is considered to have the desired effect whether it is contained in the positive electrode, the electrolyte layer, or the negative electrode. In particular, when it is contained in the negative electrode, a higher effect can be expected. For example, when an alloy-based active material (Si, Si alloy, Sn, Sn alloy, etc., especially Si) is used as the negative electrode active material, the negative electrode active material expands and contracts greatly during charging and discharging, and cracks and peeling are likely to occur in the negative electrode due to charging and discharging. However, by including the above-mentioned lithium ion conductor, the cracked interface is repaired by the lithium ion conductor, and interruptions of the ion conduction path are likely to be significantly suppressed.

[0079] In addition, reference Example 1~ 7. Examples 8 toIn 13, a lithium ion conductor containing a composite halide represented by LiGaX4 (X is one or more halogens) was applied to an all-solid-state lithium ion battery that does not substantially contain liquid, but the lithium ion conductor can also be applied to lithium ion batteries that contain liquid. However, when the lithium ion conductor is used together with a solid electrolyte, the effect of repairing cracks and peeling of the solid electrolyte is easily exhibited. In other words, the lithium ion conductor can be expected to be more effective when applied to a battery that contains a solid electrolyte.

[0080] From the above results, it can be said that a lithium ion conductor containing a complex halide represented by LiGaX4 (X is one or more halogens) is soft and has the property of increasing ion conductivity under pressure, and can cause a reaction such as a sintering reaction even at a low temperature such as room temperature. By including such a lithium ion conductor in at least one of the electrode and electrolyte layer of a lithium ion battery, even if a crack occurs in the electrode or electrolyte layer, the interface of the crack can be repaired by the lithium ion conductor, and interruption of the lithium ion conduction path can be suppressed. In other words, a lithium ion battery containing the lithium ion conductor is likely to maintain its charge and discharge characteristics even if a crack occurs in the electrolyte layer or electrode. [Explanation of symbols]

[0081] 10 positive electrode 11 Cathode active material layer 12 Positive electrode current collector 20 Electrolyte layer 30 negative electrode 31 Negative electrode active material layer 32 Negative electrode current collector 100 Lithium-ion batteries

Claims

1. A lithium ion battery having a positive electrode, an electrolyte layer, and a negative electrode, At least one of the positive electrode, the electrolyte layer, and the negative electrode includes a lithium ion conductor and a sulfide solid electrolyte; The lithium ion conductor is LiGaX ４ (X is a halogen, including Br and I), The pressure applied to the lithium ion conductor is 1 MPa or more and 100 MPa or less. Lithium-ion battery.

2. The complex halide has a first complex halide represented by LiGaXa 4 (wherein Xa is one of Br and I) and a second complex halide represented by LiGaXb 4 (wherein Xb is a halogen different from Xa and is one of Br and I); The molar ratio of the first complex halide to the second complex halide (first complex halide / second complex halide) is 1 / 4 or more and 4 or less; 2. The lithium ion battery of claim 1.

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