BATTERY

Abstract

A battery (10) includes a positive electrode active material layer (1), a negative electrode active material layer (2), and an electrolyte layer (3) disposed between the positive electrode active material layer (1) and the negative electrode active material layer (2). At least one of the positive electrode active material layer (1), the negative electrode active material layer (2), and the electrolyte layer (3) contains a Li-Al halide-based molten salt, the Li-Al halide-based molten salt containing a first salt as a main component and a second salt as a supplementary component. The first salt is a Li-Al halide salt containing at least LiAlCl4, and the second salt is an ionic liquid.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention

[0001] The present disclosure relates to a battery. 2. Description of the related art

[0002] Batteries have been actively developed in recent years. In the automotive industry, for example, batteries for battery electric vehicles (BEVs), plug-in hybrid electric vehicles (PHEVs), and hybrid electric vehicles (HEVs) are being developed. Components and materials for such batteries are also being developed.

[0003] For example, Japanese Unexamined Patent Application Laid-Open (PCT Application Translation) No. 2019-521475 discloses a battery including a first polymer electrolyte layer containing an aliphatic dinitrile compound, a lithium salt, and a lithium ion-conductive polymer; and a second polymer electrolyte layer containing an ionic liquid, a lithium salt, and a lithium ion-conductive polymer. Furthermore, Japanese Unexamined Patent Application Laid-Open No. 2023-074634 discloses that a negative electrode active material layer in an all-solid-state battery contains a molten salt. Furthermore, Japanese Unexamined Patent Application Laid-Open No. 2019-114531 discloses a liquid electrolyte composition for a lithium metal secondary battery and discloses that the liquid electrolyte composition may contain LiAlCl4. SUMMARY OF THE INVENTION

[0004] To improve battery performance, it is desirable to improve ionic conductivity and reduce battery resistance. The use of a Li-Al halide salt, such as LiAlCl4, as the electrolyte in a battery is being investigated. Since the Li-Al halide salt has low ionic conductivity, the battery resistance tends to be high in a battery using the Li-Al halide salt as the electrolyte.

[0005] The present disclosure has been developed in view of the above circumstances and provides a battery in which the battery resistance is reduced.

[0006] There is provided a battery according to a first aspect of the present disclosure, comprising: a positive electrode active material layer; a negative electrode active material layer; and an electrolyte layer disposed between the positive electrode active material layer and the negative electrode active material layer, wherein: at least one of the positive electrode active material layer, the negative electrode active material layer, and the electrolyte layer contains a Li-Al halide-based molten salt; the Li-Al halide-based molten salt contains a first salt as the main component and a second salt as the additional component; the first salt is a Li-Al halide salt containing at least LiAlCl4; and the second salt is an ionic liquid.

[0007] According to the first aspect of the present disclosure, the ratio of the first salt in the Li-Al halide-based molten salt may be not less than 50 mol% and not more than 95 mol%.

[0008] According to the first aspect of the present disclosure, the ratio of the second salt in the Li-Al halide-based molten salt may be not less than 10 mol% and not more than 30 mol%.

[0009] According to the first aspect of the present disclosure, the first salt may include LiAlCl4 and LiAlI4, and the ratio of LiAlCl4 in the first salt may be not less than 20 mol% and not more than 60 mol%.

[0010] According to the first aspect of the present disclosure, the second salt may contain, as a cationic component, at least one of a sulfonium-based cation, a pyrrolidinium-based cation, an ammonium-based cation, and a metal ion.

[0011] According to the first aspect of the present disclosure, the cationic component may be at least one of methyldiethylsulfonium, triethylsulfonium, N-methyl-N-methoxymethylpyrrolidinium, N-methyl-N-propylpyrrolidinium and 1-propyl-3-methylpyridinium.

[0012] According to the first aspect of the present disclosure, the second salt may contain, as an anion component, at least one of a sulfonylamide-based anion, a sulfuric acid-based anion, and a halogen ion.

[0013] According to the first aspect of the present disclosure, the anion component may be at least one of bis(trifluoromethanesulfonyl)amide, bis(fluorosulfonyl)amide and fluorosulfonyl(trifluoromethanesulfonylamide).

[0014] According to the first aspect of the present disclosure, the melting point of the Li-Al halide-based molten salt may be not less than 10°C and not more than 70°C.

[0015] According to the first aspect of the present disclosure, the ionic conductivity of the Li-Al halide-based molten salt at 25°C may be not less than 4.9 × 10 -5 S / cm.

[0016] According to the first aspect of the present disclosure, the ionic conductivity of the Li-Al halide-based molten salt at 25°C may be not more than 3.4 × 10 -3 S / cm.

[0017] According to the first aspect of the present disclosure, the negative electrode active material layer may contain the Li-Al halide-based molten salt.

[0018] According to the first aspect of the present disclosure, the battery may be a solid-state battery.

[0019] In the present disclosure, the effect is achieved that a battery in which the resistance is reduced can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Features, advantages and technical and industrial significance of exemplary embodiments of the invention are described below with reference to the accompanying drawings, wherein like characters denote like elements and wherein: Fig. 1 is a schematic sectional view illustrating an example of a battery according to the present disclosure. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] Hereinafter, a battery in the present disclosure will be described in detail.

[0022] Fig. 1 is a schematic sectional view illustrating, by way of example, the battery of the present disclosure. In particular, Fig. Figure 1 schematically shows the battery in the present disclosure, and the measurements and shapes of the individual sections are properly exaggerated for easy understanding. Fig.The battery 10 illustrated in Figure 1 includes a positive electrode active material layer 1, a negative electrode active material layer 2, and an electrolyte layer 3 disposed between the positive electrode active material layer 1 and the negative electrode active material layer 2. Specifically, in the battery 10 of the present disclosure, at least one of the positive electrode active material layer 1, the negative electrode active material layer 2, and the electrolyte layer 3 contains a Li-Al halide-based molten salt. Furthermore, the Li-Al halide-based molten salt contains a first salt as a main component and a second salt as an additional component, wherein the first salt is a Li-Al halide salt including at least LiAlCl4, and the second salt is an ionic liquid.

[0023] In the battery of the present disclosure, the battery resistance is reduced because at least one of the positive electrode active material layer, the negative electrode active material layer, and the electrolyte layer contains a specific Li-Al halide-based molten salt.

[0024] A Li-Al halide salt is being investigated as the electrolyte in the battery. The Li-Al halide salt exhibits relatively low ionic conductivity. It is suspected that this is due to the strong interaction between Li cations and Al halide anions, which impairs Li diffusion.

[0025] Since the Li-Al halide-based molten salt included in the battery of the present disclosure has, as its main component, the first salt, which is the Li-Al halide salt containing at least LiAlCl4, and, as its additional component, the second salt, which is the ionic liquid, excellent ionic conductivity is achieved. It is believed that this is because LiAlCl4 has relatively excellent ionic conductivity among Li-Al halide salts, and, moreover, the second salt can effectively restrict the interaction between the Li cations and the Al halide anions. As a result, the resistance of the battery containing the Li-Al halide-based molten salt is reduced.

[0026] In particular, when the battery in the present disclosure is an all-solid-state battery, the following advantages also arise. First, in the all-solid-state battery, there is a case where electrode layers such as a negative electrode active material layer expand and contract during charging and discharging, and cracks are generated. These cracks interrupt a conduction path for ions and a conduction path for electrons, resulting in an increase in battery resistance after repeated charging and discharging. Since the Li-Al halide-based molten salt in the present disclosure has a relatively low melting point, the liquid molten salt can excellently fill cracks even if the cracks occur in the electrode layers.As a result, the all-solid-state battery containing the Li-Al halide-based molten salt restrains the increase in battery resistance caused by the interruption of one conduction path for ions and one conduction path for electrons and exhibits excellent cycling characteristics. 1. Li-Al halide-based molten salt

[0027] The Li-Al halide-based molten salt in the present disclosure contains the first salt as the main component and the second salt as the additional component. The Li-Al halide-based molten salt in the present disclosure is typically included as an electrolyte in the battery. (1) First salt

[0028] The first salt is the Li-Al halide salt, which contains at least LiAlCl4. The first salt can contain only LiAlCl4 or another compound (another salt). In other words, the first salt can be a salt consisting of two or more types of salts. Furthermore, the first salt can be a eutectic salt.

[0029] For example, in the first salt, the ratio of LiAlCl4 is not less than 10 mol%, cannot be less than 20 mol%, cannot be less than 30 mol%, or cannot be less than 40 mol%. On the other hand, the ratio of LiAlCl4 can be 100 mol% or less than 100 mol%. In addition, the ratio of LiAlCl4 can be not more than 90 mol%, not more than 80 mol%, not more than 70 mol%, not more than 60 mol%, or not more than 50 mol%.

[0030] Examples of salts other than LiAlCl4 include LiAlX4 (X is any of the elements F, Br, and I). A salt other than LiAlCl4 can be used, or two or more salts other than LiAlCl4 can be used. Among these, LiAlI4 can also be used.

[0031] The Li-Al halide-based molten salt contains the first salt as the main component. "Main component" means a component included in the Li-Al halide-based molten salt in a proportion of not less than 50 mol%. The proportion of the first salt must not be less than 60 mol% or not less than 70 mol%. On the other hand, the proportion of the first salt can be, for example, not more than 95 mol%, not more than 90 mol%, or not more than 80 mol%. (2) Second salt

[0032] The second salt is the ionic liquid. The ionic liquid is a liquid-like salt with a cation component and an anion component and means a salt that is liquid, for example, at or below 100°C. The ionic liquid can be a monocation-type ionic liquid with one cation structure or a dication-type ionic liquid with two cation structures. Furthermore, in the dication-type ionic liquid, the two cation structures can be identical or different. In particular, the second salt in the present disclosure does not normally correspond to the Li-Al halide salt.

[0033] Examples of the cation component include sulfonium-based cations such as methyldiethylsulfonium (S 122 ) and triethylsulfonium (S 222 ), pyrrolidinium-based cations such as N-methyl-N-methoxymethylpyrrolidinium (P 1(101)) and N-methyl-N-propylpyrrolidinium (P 13 ), pyridinium-based cations such as 1-propyl-3-methylpyridinium (1Pr-3Me-Py), ammonium-based cations such as tetrahexylammonium (THA), and metal ions such as lithium ions. The term "sulfonium-based cation" is used in particular for a cation with a sulfonium group (R 1 (R 2 )(R 3 )S + , where each of the residues R 1 to R 3 is a hydrogen or an organic group. Likewise, the terms "pyrrolidinium-based," "pyridinium-based," and "ammonium-based" are used for cations with a pyrrolidinium group, a pyridinium group, or an ammonium group, respectively. The second salt can contain one type of cation or two or more types of cations.

[0034] Among the cation components mentioned above, sulfonium-based cations, pyrrolidinium-based cations, and pyridinium-based cations can be used. This is due to their large molecular weights and bulkiness. When the second salt contains the bulky cation component, the interaction between Li and Al halide anions in the first salt can be weakened, resulting in a Li-Al halide-based molten salt with better ionic conductivity.

[0035] Examples of the anion component include sulfonylamide-based anions such as bis(trifluoromethanesulfonyl)amide (TFSA), bis(fluorosulfonyl)amide (FSA), and fluorosulfonyl(trifluoromethanesulfonylamide) (FTA), sulfuric acid-based anions such as hydrogen sulfate ion, and halogen ions such as chloride ion. Examples of the anion component also include boron fluoride anion, phosphorus fluoride ion, and trifluoromethanesulfonate. The second salt may contain one type of anion component or contain two or more types of anion components.

[0036] Sulfonylamide-based anions can be used as the anion component. This is due to their large molecular weight and bulkiness. It is believed that the bulky anion component can weaken the interaction between Li and Al halide anions in the first salt.

[0037] The second salt can be one type of salt or a salt formed from two or more types of salts.

[0038] The Li-Al halide-based molten salt contains the second salt (ionic liquid) as an additional component. The "additional component" refers to a component that is present in the Li-Al halide-based molten salt in a smaller proportion than that of the first salt as the main component.

[0039] The proportion of the second salt in the Li-Al halide-based molten salt is, for example, not less than 5 mol%, may not be less than 10 mol%, may not be less than 15 mol%, or may not be less than 20 mol%. On the other hand, the proportion of the second salt is, for example, not more than 40 mol%, may not be more than 35 mol%, may not be more than 30 mol%, or may not be more than 25 mol%.

[0040] In addition, in the Li-Al halide-based molten salt, the ratio of the second salt to the first salt is, for example, not less than 5 mol% and not more than 45 mol%. (3) Li-Al halide-based molten salt

[0041] The melting point of the Li-Al halide-based molten salt is, for example, 100°C, may not exceed 80°C, may not exceed 70°C, may not exceed 60°C, or may not exceed 50°C. On the other hand, the melting point is, for example, not less than 10°C, not less than 20°C, not less than 30°C, or not less than 40°C. The melting point can be determined, for example, by differential scanning calorimetry (DSC measurement).

[0042] The ionic conductivity of the Li-Al halide-based molten salt (ionic conductivity at 25°C) is not specifically limited and can be high. For example, the ionic conductivity is not less than 4.5 × 10 -5S / cm, can not be less than 4.9 × 10 -5 S / cm, can not be less than 1.0 × 10 -4 S / cm, can not be less than 3.0 × 10 -4 S / cm or can not be less than 5.0 × 10 -4 S / cm. On the other hand, the ionic conductivity, for example, is not more than 4.0 × 10 -3 S / cm, can not exceed 3.4 × 10 -3 S / cm, can not exceed 3.0 × 10 -3 S / cm, can not exceed 2.0 × 10 -3 S / cm or can not exceed 1.5 × 10 -3 S / cm. Ionic conductivity can be determined, for example, using an alternating current impedance method.

[0043] In the battery, the Li-Al halide-based molten salt is contained in the positive electrode active material layer, the negative electrode active material layer, and / or the electrolyte layer. The Li-Al halide-based molten salt may be contained only in the positive electrode active material layer, only in the negative electrode active material layer, or only in the electrolyte layer. Otherwise, the Li-Al halide-based molten salt may be contained in any two of the positive electrode active material layer, the negative electrode active material layer, and the electrolyte layer, or in all three layers. Specifically, in the battery of the present disclosure, the Li-Al halide-based molten salt may be contained in the negative electrode active material layer.The Li-Al halide-based molten salt can be used in conjunction with another electrolyte in the positive electrode active material layer, the negative electrode active material layer, and the electrolyte layer. The other electrolyte will be mentioned later.

[0044] In addition, the Li-Al halide-based molten salt can be prepared by a method described for examples. 2. Positive electrode active material layer

[0045] The positive electrode active material layer contains at least one positive electrode active material.

[0046] Examples of positive electrode active materials include oxide active materials. Examples of oxide active materials include layered rock salt-type active materials such as LiNi 1 / 3 CO 1 / 3 Mn 1 / 3 02 and LiNi 0,8 Co 0,15 Al 0,05O2, spinel-type active materials such as LiMn2O4, and olivine-type active materials such as LiFePO4. Sulfur (S) can also be used for the positive electrode active material.

[0047] For example, one form of positive electrode active material is particulate. The average particle size (D 50 ) of the positive electrode active material is, for example, not less than 0.5 µm and not more than 50 µm. The average particle size (D 50 ) is a volume-cumulative particle diameter measured with a laser diffraction particle size distribution measuring device. For example, the ratio of the positive electrode active material in the positive electrode active material layer is not less than 50 wt% and not more than 80 wt%.

[0048] The positive electrode active material layer may contain at least an electrolyte, a conductive material, and a binder, as required. The positive electrode active material layer may or may not contain the above-mentioned Li-Al halide-based molten salt as the electrolyte. Furthermore, the positive electrode active material layer may contain only the Li-Al halide-based molten salt as the electrolyte, or it may contain the Li-Al halide-based molten salt and another electrolyte. The electrolyte is described in "4. Electrolyte Layer."

[0049] Examples of the conductive material include carbon materials. Examples of carbon materials include particulate carbon materials such as acetylene black (AB) and Ketjen black (KB), as well as fibrous carbon materials such as carbon fibers, carbon nanotubes (CNTs), and carbon nanofibers (CNFs). The proportion of the conductive material in the positive electrode active material layer is, for example, not less than 0.01 wt% and not more than 10 wt%.

[0050] Examples of the binder include rubber-based binders such as butadiene rubber (BR), acrylate butadiene rubber (ABR), and styrene butadiene rubber (SBR), as well as fluorine-containing binders such as polyvinylidene fluoride (PVDF) and polytetrafluoroethylene (PTFE). The binder content in the positive electrode active material layer is, for example, not less than 0.5 wt% and not more than 10 wt%.

[0051] The thickness of the positive electrode active material layer is not specifically limited and is, for example, not less than 0.1 µm and not more than 1000 µm. 3. Negative electrode active material layer

[0052] The negative electrode active material layer contains at least one negative electrode active material.

[0053] Examples of the negative electrode active material include a Si-based active material. The Si-based active material is an active material containing a Si element. Examples of the Si-based active material include a simple Si substance, a Si alloy, and a Si oxide. The Si alloy may contain the Si element as a main component. The ratio of the Si element in the Si alloy is, for example, not less than 50 mol%, not less than 70 mol%, or not less than 90 mol%. On the other hand, the ratio of the Si element in the Si alloy is, for example, not more than 99 mol%.Examples of Si alloys include Si-Al-based alloys, Si-Sn-based alloys, Si-In-based alloys, Si-Ag-based alloys, Si-Pb-based alloys, Si-Sb-based alloys, Si-Bi-based alloys, Si-Mg-based alloys, Si-Ca-based alloys, Si-Ge-based alloys, Si-Pb-based alloys, and the like. Si alloys may be two-component alloys or multi-component alloys composed of three or more components. Examples of Si oxides include SiO.

[0054] Furthermore, the Si-based active material can have a diamond-like crystal phase, a Type I clathrate crystal phase, or a Type II clathrate crystal phase. In the Type I or Type II clathrate crystal phase, a polyhedron (cage) containing pentagons or hexagons is formed with a plurality of Si elements. Since this polyhedron has an internal space in which a clathrate of metal ions such as Li ions can form, volume change during charging and discharging can be limited. In addition, the Si-based active material can have voids in its primary particles. These voids can limit the volume change of the active material and prevent cracks in the negative electrode active material layer. The porosity is not specifically limited and is, for example, not less than 4% and not more than 40%.The presence of voids and porosity in the primary particles can be investigated by scanning electron microscopy (SEM) observation.

[0055] The negative electrode active material layer may contain at least an electrolyte, a conductive material, and a binder as needed. The negative electrode active material layer may or may not contain the above-mentioned Li-Al halide-based molten salt as the electrolyte, and the former may also be used. Furthermore, the negative electrode active material layer may contain only the Li-Al halide-based molten salt as the electrolyte, or it may contain the Li-Al halide-based molten salt and another electrolyte. The electrolyte, the Li-Al halide-based molten salt, the conductive material, and the binder are as described in "2. Positive Electrode Active Material Layer."

[0056] The thickness of the negative electrode active material layer is not specifically limited and is, for example, not less than 0.1 µm and not more than 1000 µm. 4. Electrolyte layer

[0057] The electrolyte layer contains at least one electrolyte. Furthermore, the electrolyte layer may or may not contain the aforementioned Li-Al halide-based molten salt as the electrolyte. Furthermore, the electrolyte layer may contain only the Li-Al halide-based molten salt or the Li-Al halide-based molten salt and another electrolyte as the electrolyte.

[0058] In the electrolyte layer, the ratio of the Li-Al halide-based molten salt to the total electrolyte can be 100 wt% or less than 100 wt%. In the latter case, the ratio is, for example, not less than 10 wt% and not more than 80 wt%.

[0059] The electrolyte layer may contain an electrolyte other than the Li-Al halide-based molten salt. Examples of the electrolyte include a solid electrolyte. Examples of the solid electrolyte include inorganic solid electrolytes such as a sulfide solid electrolyte, an oxide solid electrolyte, and a halide solid electrolyte. The sulfide solid electrolyte may contain sulfur (S) as the main component of the anion elements. The oxide solid electrolyte may contain oxygen (O) as the main component of the anion elements. The halogen-based solid electrolyte may contain halogen as the main component of the anions. Among these, the sulfide solid electrolyte can also be used.

[0060] The sulfide solid electrolyte may contain a Li element, an M element (M is at least one of P, Sn, Al, Zn, In, Ge, Si, Sb, Ga, and Bi), and an S element. Furthermore, the sulfide solid electrolyte may contain a halogen element such as F, Cl, Br, and I. Furthermore, one or more S elements may be substituted with O elements in the sulfide solid electrolyte.

[0061] The sulfide solid electrolyte can be a glass-based (amorphous) sulfide solid electrolyte, a glass-ceramic sulfide solid electrolyte, or a crystalline sulfide solid electrolyte. Examples of crystal phases contained in the sulfide solid electrolyte include an LGPS-type crystal phase, a thio-LISICON-type crystal phase, and an argyrodite-type crystal phase.

[0062] Examples of the sulfide solid electrolyte include Li2S-P2S5, Li2S-P2S5-LiI, Li2S-P2S5-GeS2, Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, Li2S-P2S5-LiI-LiBr, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, Li2S-B2S3, Li2S-P2S5-Z m S n (where m and n are positive numbers and Z is one of Ge, Zn and Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li x MO y (where x and y are positive numbers and M is one of P, Si, Ge, B, Al, Ga and In).

[0063] In addition, the electrolyte layer may contain a binder as needed. The binder corresponds to that described in "2. Positive Electrode Active Material Layer."

[0064] The thickness of the electrolyte layer is not specifically limited and is, for example, not less than 0.1 µm and not more than 1000 µm. 5. Other configurations

[0065] As in Fig.As shown in Figure 1, the battery 10 in the present disclosure typically includes a positive electrode current collector body 4 that collects electrons from the positive electrode active material layer 1, and a negative electrode current collector body 5 that collects electrons from the negative electrode active material layer 2. Examples of the material of the positive electrode current collector include SUS, aluminum, nickel, iron, titanium, and carbon. Examples of the material of the negative electrode current collector body include SUS, copper, nickel, and carbon.

[0066] Furthermore, the battery in the present disclosure may include an outer body that accommodates the aforementioned elements. Examples of the outer body include a laminate-type outer body and a case-type outer body. Furthermore, the battery in the present disclosure may include a clamping device that applies a confining pressure in the thickness direction to the aforementioned elements. Any known device can be used as the restricting device. For example, the limiting pressure is not less than 0.1 MPa and not more than 50 MPa, or not less than 1 MPa and not more than 20 MPa. 6. Battery

[0067] The battery in the present disclosure is typically a lithium-ion secondary battery. Furthermore, the battery in the present disclosure may be a liquid battery or a solid-state battery. If the electrolyte layer in the battery contains an electrolyte that is solid at ambient temperature (e.g., an inorganic solid electrolyte), the battery may be considered a solid-state battery. Furthermore, the solid-state battery may be a semi-solid-state battery or a solid-state battery. If the electrolyte layer in the battery contains an electrolyte that is solid at ambient temperature and an electrolyte that is liquid at ambient temperature (e.g., a molten salt), the battery may be considered a semi-solid-state battery.If the electrolyte layer in the battery contains only an electrolyte that is solid at ambient temperature, the battery can also be considered a solid-state battery.

[0068] Examples of applications of the battery include power supplies for vehicles such as a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), a battery electric vehicle (BEV), a gasoline car, and a diesel car. Furthermore, the battery in the present disclosure may be used for power supplies for moving bodies (e.g., a railway, a ship, and an aircraft) other than vehicles, or may be used for power supplies for electrical devices such as information processing devices.

[0069] In particular, the present disclosure is not limited to the aforementioned embodiment. The aforementioned embodiment is an exemplary illustration, and anything having a substantially equivalent configuration to that based on the technical concept disclosed in the claims of the present disclosure and achieving a similar effect(s) is included within the technical scope of the present disclosure. Example 1: Making the first salt

[0070] A total of 10 g of LiCl and AlCl3, as well as 100 g of heptane, were weighed as raw materials. These were placed in a Fritsch ball mill (size: 500 ml; balls used: ZrO2) and ground for 20 hours at 300 rpm. This yielded LiAlCl4. LiAlI4 was obtained using the same procedure using LiI and AlI3 as raw materials. LiAlCl4 and LiAlI4 were mixed in a molar ratio of 20:80. This yielded a first salt (eutectic Li-Al halide salt: 20LiAlCl4-80LiAlI4). Making a molten salt

[0071] The second salt was an ionic liquid (S 122 TFSA), which consists of methyldiethylsulfonium (S 122) as the cation component and bis(trifluoromethanesulfonyl)amide (TFSA) as the anion component. The first salt and the second salt were mixed in a screw-top bottle. They were then heated to 160°C with a hot stirrer and stirred to form a homogeneous compound (molten salt) in a molten state. Specifically, the first salt and the second salt were added in appropriate amounts so that the ratio of the second salt in the molten salt was 30 mol%. The evaluations mentioned later were conducted using the obtained molten salt as a sample. Example 2 to Example 21

[0072] Each molten salt was obtained as in Example 1, except that at least one of the types of the first salt, the type of the second salt, and the ratio of the second salt was changed as shown in Table 1. Comparative Example 1 to Comparative Example 6

[0073] The salt shown in Table 1 was prepared as a sample in each case, whereby the second salt was not used. Comparative Example 7 to Comparative Example 9

[0074] The salt (LiAlI4) containing no LiAlCl4 and the second salt shown in Table 1 were prepared to prepare a molten salt (sample) according to a similar procedure as in Example 1 with the ratio shown in Table 1. ReviewsMeasurement of the melting point

[0075] The melting point was determined by DSC measurement. Specifically, each sample was enclosed and sealed in an aluminum tray. The temperature of this tray was increased from -100°C to 100°C at a rate of 5°C / min using a DSC meter for very low temperatures (DSC-200 F3) manufactured by NETZSCH. From the obtained profile, the inflection point of an endothermic change indicating melting was determined as the melting point. Meanwhile, for one sample (a high-melting-point sample) in which an inflection point in an endothermic change was observed only at 100°C, the temperature was increased from room temperature to 200°C at 5°C / min using a meter (DSC-60) manufactured by Shimadzu Corporation. From the obtained profile, the inflection point of an endothermic change indicating melting was determined as the melting point. Table 1 shows the results. Measurement of ionic conductivity

[0076] Ionic conductivity was determined by impedance measurement. Specifically, each sample was first melted into a liquid state. The liquid sample was filled into a battery evaluation batch cell (SB1A) manufactured by EC FRONTIER CO., LTD. to perform an impedance measurement at 25°C. The ionic conductivity was calculated from the resulting resistance value and the shape factor. Table 1 shows the results. [Table 1] First salt Second salt Melting point (°C) Ionic conductivity (S / cm) type Ratio (mol%) Comparison example 1 LiAlI4 - - 210 1,0×10 -5 Comparison example 2 20LiAlCl4-80LiAlI4 - - 137 7,5×10 -6 Comparison example 3 40LiAlCl4-60LiAlI4 - - 72 7,4×10 -6 Comparison example 4 60LiAlCl4-40LiAlI4 - - 73 3,7×10 -6 Comparison example 5 80LiAICl4-20LiAlI4 - - 70 3,4×10 -7 Comparison example 6 LiAlCl4 - - 140 8,8×10 -8 Comparison example 7 LiAll4 P 1(101) TFSA 30 123 1,1×10 -6 Comparison example 8 LiAll4 P 1(101) TFSA 40 82 3,8×10 -6 Comparison example 9 LiAll4 P 13 TFSA 30 78 2,3×10 -8 Example 1 20LiAlCl4-80LiAll4 S 122 TFSA 30 10 4,0×10 -4 Example 2 20LiAlCl4-80LiAll4 1 Pr-3Me-PyTFSA 30 Hypothermia 1,4× 10 -4 Example 3 40LiAlCl4-60LiAll4 S 222 TFSA 10 41 1,8×10 -4 Example 4 40LiAlCl4-60LiAll4 S 122 TFSA 30 Hypothermia 7,3×10- 4 Example 5 40LiAlCl4-60LiAll4 P 13 TFSA 30 4 3,3×10 4 Example 6 40LiAlCl4-60LiAll4 1 Pr-3Me-PyTFSA 30 Hypothermia 4,9×10 -4 Example 7 60LiAlCl4-40LiAlI4 LiTFSA 10 57 7,6×10 -5 Example 8 60LiAlCl4-40LiAlI4 LiFTA 10 45 4,5×10 -4 Example 9 60LiAlCl4-40LiAlI4 LiFSA 10 58 1,1×10 -4 Example 10 60LiAlCl4-40LiAlI4 THACI 10 53 1,2×10 -4 Example 11 60LiAlCl4-40LiAlI4 THAHSO4 10 29 4,9×10 -5 Example 12 60LiAlCl4-40LiAlI4 S 122 TFSA 10 52 2,3×10 -4 Example 13 60LiAlCl4-40LiAlI4 S 222 TFSA 10 45 7,6×10 -5 Example 14 60LiAlCl4-40LiAlI4 S 122 TFSA 20 30 9,8×10 -4 Example 15 60LiAlCl4-40LiAlI4 S 222 TFSA 20 28 1,2×10 -3 Example 16 60LiAlCl4-40LiAlI4 S 122 TFSA 30 24 1,3×10 -3 Example 17 60LiAlCl4-40LiAlI4 P 13 TFSA 30 16 3,6×10 -4 Example 18 60LiAlCl4-40LiAlI4 P1( 101 )TFSA 30 30 1,5×10 -4 Example 19 60LiAlCl4-40LiAlI4 1Pr-3Me-PyTFSA 30 Hypothermia 1,1×10 -3 Example 20 LiAlCl4 S 122 TFSA 20 16 3,4×10 -3 Example 21 LiAlCl4 P 1(101) TFSA 30 21 1,5×10 -3

[0077] As shown in Table 1, the Li-Al halide-based molten salts in the present disclosure exhibited ionic conductivities of not less than 4.9 × 10 -5S / cm and exhibited more excellent ionic conductivities than in the comparative examples. This indirectly demonstrated that the battery resistance was reduced in the battery containing the Li-Al halide-based molten salt in the present disclosure. According to Table 1, the samples of Example 2, Example 4, Example 6, and Example 19 were in a state of supercooling during DSC measurement, and it can be concluded that their melting points were close to room temperature. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2019-521475

[0003] JP 2023-074634

[0003] JP 2019-114531

[0003]

Claims

[1] Battery (10) comprising: a positive electrode active material layer (1); a negative electrode active material layer (2); and an electrolyte layer (3) arranged between the positive electrode active material layer (1) and the negative electrode active material layer (2), wherein: at least one of the positive electrode active material layer (1), the negative electrode active material layer (2) and the electrolyte layer (3) contains a Li-Al halide-based molten salt; the Li-Al halide-based molten salt contains a first salt as a main component and a second salt as an additional component; the first salt is a Li-Al halide salt containing at least LiAlCl4; and the second salt is an ionic liquid. [2] The battery (10) according to claim 1, wherein a ratio of the second salt in the Li-Al halide-based molten salt is not less than 10 mol% and not more than 30 mol%. [3] Battery (10) according to claim 1, wherein: the first salt contains LiAlCl4 and LiAlI4; and a ratio of LiAlCl4 in the first salt is not less than 20 mol% and not more than 60 mol%. [4] The battery (10) according to claim 1, wherein the second salt contains as a cation component at least one of a sulfonium-based cation, a pyrrolidinium-based cation, an ammonium-based cation and a metal ion. [5] The battery (10) of claim 4, wherein the cationic component is at least one of methyldiethylsulfonium, triethylsulfonium, N-methyl-N-methoxymethylpyrrolidinium, N-methyl-N-propylpyrrolidinium, and 1-propyl-3-methylpyridinium. [6] The battery (10) according to claim 1, wherein the second salt contains as an anion component at least one of a sulfonylamide-based anion, a sulfuric acid-based anion, and a halogen ion. [7] The battery (10) of claim 6, wherein the anion component is at least one of bis(trifluoromethanesulfonyl)amide, bis(fluorosulfonyl)amide, and fluorosulfonyl(trifluoromethanesulfonylamide). [8] The battery (10) according to claim 1, wherein the melting point of the Li-Al halide-based molten salt is not less than 10°C and not more than 70°C. [9] The battery (10) according to claim 1, wherein an ionic conductivity of the Li-Al halide-based molten salt at 25°C is not less than 4.9 × 10 -5 S / cm. [10] Battery (10) according to claim 1, wherein an ionic conductivity of the Li-Al halide-based molten salt at 25°C is not more than 3.4 × 10 -3 S / cm.

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