Battery

Abstract

The purpose of the present invention is to provide an intrinsically safe battery that can be stably charged and discharged even at a high temperature of 80°C or higher, and can exhibit a high coulombic efficiency and cycle capacity retention rate. This battery includes: a positive electrode containing a positive electrode active material; a negative electrode containing a negative electrode active material capable of inserting and desorbing carrier ions at 0.1 V (vs. Li / Li+) or more; and an electrolyte layer arranged between the positive electrode and the negative electrode. At least one of the positive electrode, the negative electrode, and the electrolyte layer includes a solid electrolyte represented by Mα aMβ bMγ cXd (where in the formula, Mα is at least one selected from the group consisting of Li, Na, and K, Mβ is an element that provides a trivalent cation, Mγ is an element that provides a tetravalent cation, X is at least one selected from the group consisting of F, Cl, Br, and I, and a, b, c, and d satisfy 0.9(3 - x) ≤ a ≤ 1.1(3 - x), 0.9(1 - x) ≤ b ≤ 1.1(1 - x), 0.9x ≤ c ≤ 1.1x, 5.4 ≤ d ≤ 6.6, and 0 < x < 1).

Description

battery

[0001] The present disclosure relates to batteries.

[0002] In recent years, with the development of portable devices such as personal computers and mobile phones, the demand for batteries as their power sources has expanded significantly. Batteries used for such applications have traditionally used organic electrolytes, in which an electrolyte is dissolved in a flammable organic solvent, as a medium for ion transfer. Batteries containing such organic electrolytes may pose safety issues, such as fires and explosions. Therefore, to ensure essential safety, development of all-solid-state batteries that use solid electrolytes instead of organic electrolytes has been promoted. Such all-solid-state batteries are inherently safe because the electrolyte is a non-flammable material and there is no risk of fire or explosion.

[0003] Solid electrolytes, such as sulfide-based solid electrolytes, are widely known to react with water to generate toxic hydrogen sulfide gas. Meanwhile, oxide-based solid electrolytes, which do not generate toxic gases like hydrogen sulfide, are also being widely developed. However, because they require densification through high-temperature sintering to increase conductivity, they can react with the active material during battery manufacturing, resulting in high resistance.

[0004] In recent years, halogenated solid electrolytes have been proposed. For example, Patent Document 1 (WO2019 / 135315) describes a lithium ion battery. ３ YX ６ (wherein X is two or more elements selected from the group consisting of Cl, Br, and I) and a battery containing this solid electrolyte material in at least one of the positive electrode, negative electrode, and electrolyte layer has also been disclosed. ６－（４－ｘ）ｂ (Zr １－ｘ Al ｘ ) ｂ F ６ (wherein 0<x<1 and 0<b≦1.5) and having a predetermined XRD peak profile. Also disclosed is a battery containing this solid electrolyte material in at least one of a positive electrode, a negative electrode, and an electrolyte layer.

[0005] WO2019 / 135315WO2023 / 013390

[0006] However, the halogenated solid electrolyte disclosed in Patent Document 1 is thermally unstable and has poor charge / discharge performance at high temperatures, and the solid electrolyte disclosed in Patent Document 2 has low ionic conductivity.

[0007] The present inventors have now discovered that by incorporating a halogenated solid electrolyte of a predetermined composition into at least one of the positive electrode, negative electrode, and electrolyte layer, it is possible to provide an essentially safe battery that is capable of stable charge and discharge even at high temperatures of 80°C or higher, and that exhibits high coulombic efficiency and cycle capacity retention rate.

[0008] Therefore, an object of the present invention is to provide an essentially safe battery that can be stably charged and discharged even at high temperatures of 80°C or higher, and that can exhibit high coulombic efficiency and cycle capacity retention rate.

[0009] According to the present disclosure, the following aspects are provided: [Aspect 1] A positive electrode including a positive electrode active material, and a positive electrode active material having a voltage of 0.1 V (vs. Li / Li ＋ ) or more, and an electrolyte layer disposed between the positive electrode and the negative electrode, wherein at least one of the positive electrode, the negative electrode, and the electrolyte layer is represented by the following composition formula: M α ａ M β ｂ M γ ｃ X ｄ (In the formula, M α is at least one selected from the group consisting of Li, Na, and K, and M β is an element that provides a trivalent cation, and M γis an element that provides a tetravalent cation, X is at least one selected from the group consisting of F, Cl, Br, and I, and a, b, c, and d satisfy the following: 0.9(3-x)≦a≦1.1(3-x), 0.9(1-x)≦b≦1.1(1-x), 0.9x≦c≦1.1x, 5.4≦d≦6.6, and 0<x<1. [Aspect 2] The battery according to Aspect 1, wherein each of the positive electrode, the negative electrode, and the electrolyte layer contains the solid electrolyte. [Aspect 3] The battery according to Aspect 1, wherein the M α The battery according to aspect 1 or 2, wherein the M β The battery according to any one of Aspects 1 to 3, wherein the M contains Al. γ The battery according to any one of Aspects 1 to 4, wherein X comprises Si and / or Ge. [Aspect 6] The battery according to any one of Aspects 1 to 5, wherein X comprises F. [Aspect 7] The battery according to any one of Aspects 1 to 5, wherein M α contains Li, and the M β contains Al, and the M γ The battery according to any one of Aspects 1 to 6, wherein the solid electrolyte is Li ａ Al ｂ Si ｃ F ｄ The battery according to any one of Aspects 1 to 7, wherein the positive electrode active material comprises at least one selected from the group consisting of lithium nickel manganese oxide (LNMO), lithium nickel cobalt manganese oxide (NCM), lithium cobalt oxide (LCO), lithium nickel cobalt aluminum oxide (NCA), and lithium iron phosphate (LFP). [Aspect 10] The battery according to any one of Aspects 1 to 8, wherein the negative electrode active material comprises at least one selected from the group consisting of lithium titanate (LTO), SiO, Si or a Si alloy, and TiO ２ The battery according to any one of Aspects 1 to 9, comprising at least one selected from the group consisting of: [Aspect 11] The battery according to any one of Aspects 1 to 10, wherein none of the positive electrode, the negative electrode, and the electrolyte layer contains sulfide.

[0010] 1 is a schematic cross-sectional view showing an example of an all-solid-state battery according to the present invention; 2 is a charge / discharge curve of an all-solid-state battery produced in Example 1 (Comparative Example); 3 is a charge / discharge curve of an all-solid-state battery produced in Example 2; 4 is a charge / discharge curve of an all-solid-state battery produced in Example 4;

[0011] The battery of the present invention is typically an all-solid-state battery, but is not limited to an all-solid-state battery and may be a battery that uses a combination of a solid material (such as a solid electrolyte) and a liquid material (such as an electrolytic solution or an ionic liquid), which is called a semi-solid battery, or may be another type of battery.

[0012] FIG. 1 shows a schematic diagram of an example of an all-solid-state battery 10 according to the present invention. The battery 10 includes a positive electrode 12, a negative electrode 14, and an electrolyte layer 16. The positive electrode 12 includes a positive electrode active material. The negative electrode 14 is connected to a positive electrode 16 at a potential of 0.1 V (vs. Li / Li ＋ ) and includes a negative electrode active material capable of inserting and desorbing carrier ions. The electrolyte layer 16 is disposed between the positive electrode 12 and the negative electrode 14. At least one of the positive electrode 12, the negative electrode 14, and the electrolyte layer 16 includes a solid electrolyte. This solid electrolyte is M α ａ M β ｂ M γ ｃ X ｄ (In the formula, M α is at least one selected from the group consisting of Li, Na, and K, and M β is an element that provides a trivalent cation, and M γ is an element that provides a tetravalent cation, X is at least one selected from the group consisting of F, Cl, Br, and I, and a, b, c, and d satisfy 0.9(3−x)≦a≦1.1(3−x), 0.9(1−x)≦b≦1.1(1−x), 0.9x≦c≦1.1x, 5.4≦d≦6.6, and 0<x<1. By incorporating a halogenated solid electrolyte of the above composition into at least one of the positive electrode 12, the negative electrode 14, and the electrolyte layer 16, it is possible to provide an essentially safe battery 10 that can be stably charged and discharged (not only at room temperature) but also at high temperatures of 80° C. or higher (e.g., 100° C. or 150° C.), and that can exhibit high coulombic efficiency and cycle capacity retention.

[0013] That is, the halogenated solid electrolyte of the above composition used in the present invention is a non-flammable and chemically stable material, thereby providing an essentially safe battery. Furthermore, this solid electrolyte can be densified by the pressure of press molding rather than sintering, and therefore does not react with the active material to increase resistance during battery fabrication. Furthermore, solid electrolytes containing halogen elements such as F exhibit high electrochemical stability and high thermal stability, thereby enabling stable charge / discharge even at temperatures above 80°C, and realizing all-solid-state batteries with high Coulombic efficiency and cycle capacity retention. In this regard, conventional halogenated solid electrolytes and batteries using such electrolytes, such as those disclosed in References 1 and 2, have problems such as thermal instability, poor charge / discharge performance at high temperatures, and low ionic conductivity. However, these problems can be successfully solved by the present invention.

[0014] As described above, the battery 10 of the present invention is typically an all-solid-state battery or an all-solid-state secondary battery. For example, the battery 10 can be a lithium-ion secondary battery (typically an all-solid-state lithium-ion secondary battery), a sodium-ion secondary battery (typically an all-solid-state sodium-ion secondary battery), or a potassium-ion secondary battery (typically an all-solid-state potassium-ion secondary battery). An all-solid-state lithium-ion secondary battery is particularly preferred. Therefore, although the following description of the positive electrode 12 and the negative electrode 14 mainly assumes an all-solid-state lithium-ion secondary battery, this does not in any way exclude the application of the present invention to other batteries.

[0015] The positive electrode 12 includes a positive electrode active material. The positive electrode active material preferably includes a lithium composite oxide. Examples of lithium composite oxides include lithium nickel manganese oxide (LNMO) (typically LiNi ０．５ Mn １．５ O ４ ), lithium nickel cobalt manganese oxide (NCM) (typically Li(Ni,Co,Mn)O ２ ), lithium cobalt oxide (LCO) (typically LiCoO ２ ), lithium nickel cobalt aluminate (NCA) (typically Li(Ni,Co,Al)O ２) and lithium iron phosphate (LFP) (typically LiFePO ４ ), and combinations thereof. NCM, LCO, and NCA have a layered rock salt structure. LNMO has a spinel structure. LFP has an olivine structure. A lithium composite oxide having a layered rock salt structure, such as NCM, is preferred. The positive electrode 12 preferably further contains a solid electrolyte and / or an electron conductive additive (carbon black, etc.) in addition to the positive electrode active material. The positive electrode 12 in this embodiment is formed by integrating these materials by pressure or heat. Therefore, as shown in FIG. 1, the positive electrode 12 is typically in the form of a positive electrode layer. When the positive electrode 12 contains a solid electrolyte, it is preferable to use such a solid electrolyte as described below.

[0016] The negative electrode 14 is 0.1 V (vs. Li / Li ＋ ) or more. The carrier ions are necessarily determined depending on the type of battery 10, and are not particularly limited. For example, the carrier ions are lithium ions in lithium ion secondary batteries, sodium ions in sodium ion secondary batteries, and potassium ions in potassium ion secondary batteries. ＋ ) or more can be applied not only to lithium ions but also to sodium ions and potassium ions (because the standard electrode potential of Na is 0.33 V higher than the standard electrode potential of Li, and the standard electrode potential of K is 0.11 V higher than the standard electrode potential of Li). Examples of negative electrode active materials include lithium titanate (LTO) (typically Li ４ Ti ５ O １２ ), SiO, Si or Si alloy, and TiO ２ The negative electrode active material is preferably LTO, SiO, or TiO in view of non-flammability. ２ In terms of cycleability, LTO is particularly preferred. Although LTO is typically known to have a spinel structure, it can also have other structures during charge and discharge. For example, LTO can have Li ４ Ti ５ O １２ (spinel structure) and Li ７ Ti５ O １２ The reaction proceeds in the coexistence of two phases, a solid electrolyte (rock salt structure) and a solid electrolyte (rock salt structure). Therefore, LTO is not limited to a spinel structure. From the viewpoint of improving ionic conductivity, it is preferable that the negative electrode 14 further contains a solid electrolyte in addition to the negative electrode active material. The negative electrode 14 may further contain an electron conduction aid (carbon black, etc.). The negative electrode 14 in this embodiment is formed by integrating these materials by pressure or heat. Therefore, as shown in FIG. 1, the negative electrode 14 is typically in the form of a negative electrode layer. When the negative electrode 14 contains a solid electrolyte, it is preferable to use such a solid electrolyte as described below.

[0017] The electrolyte layer 16 is a layer containing an electrolyte and disposed between the positive electrode 12 and the negative electrode 14. Typically, the electrolyte layer 16 contains a solid electrolyte, and is preferably made of a solid electrolyte. In this case, the electrolyte layer 16 can be said to also function as a separator. The solid electrolyte contained in the electrolyte layer 16 is preferably one described below.

[0018] At least one of the positive electrode 12, the negative electrode 14, and the electrolyte layer 16 includes a solid electrolyte. The solid electrolyte has the following composition formula: α ａ M β ｂ M γ ｃ X ｄ (In the formula, M α is at least one selected from the group consisting of Li, Na, and K, and M β is an element that provides a trivalent cation, and M γis an element that provides a tetravalent cation, X is at least one selected from the group consisting of F, Cl, Br, and I, and a, b, c, and d satisfy the following conditions: 0.9(3-x)≦a≦1.1(3-x), 0.9(1-x)≦b≦1.1(1-x), 0.9x≦c≦1.1x, 5.4≦d≦6.6, and 0<x<1. This solid electrolyte exhibits high ionic conductivity (e.g., lithium ion conductivity). Furthermore, this solid electrolyte is non-flammable and chemically stable, and does not generate hydrogen sulfide gas, thereby achieving an intrinsically safe battery 10. However, it is not necessary for all of the positive electrode 12, the negative electrode 14, and the electrolyte layer 16 to contain the solid electrolyte; at least one of them may contain the solid electrolyte.

[0019] The meaning of the above composition formula is explained as follows. First, the above solid electrolyte is typically M α , M β and compounds containing X (e.g., Li ３ AlF ６ ) and M α ２ M γ X ６ (For example, Li ２ SiF ６ For example, the solid electrolyte may be obtained by mixing a compound represented by M α ３ M β X ６ and M α ２ M γ X ６ It is obtained by mixing M α ３ M β X ６ and M α ２ M γ X ６ When the two are mixed in such a manner that the ratio of the amounts of substances is (1-x):x (where 0<x<1), the solid electrolyte has the composition formula M α ３－ｘ M β １－ｘ M γ ｘ X ６If this composition is allowed to have a tolerance of ±0.1 times in consideration of measurement errors, etc. (i.e., the numerical range is from the lower limit multiplied by 0.9 to the upper limit multiplied by 1.1), M α , M β , M γ As described above, the ratios of the amounts of substances a:b:c:d of X are 0.9(3-x)≦a≦1.1(3-x), 0.9(1-x)≦b≦1.1(1-x), 0.9x≦c≦1.1x, and 5.4≦d≦6.6. In other words, within these numerical ranges, it can be said that the desired performance of the solid electrolyte (e.g., high ionic conductivity) can be equally obtained. In the above composition formula, it is preferable that 0.05≦x≦0.8 is satisfied, and more preferably 0.05≦x≦0.6. This allows for further improvement in ionic conductivity, such as lithium ion conductivity.

[0020] M α is at least one selected from the group consisting of Li, Na, and K. In the case of a lithium ion secondary battery, M α Preferably, M contains Li, and more preferably, M α is Li. In the case of a sodium ion secondary battery, M α Preferably, contains Na, more preferably, M α is Na. In the case of a potassium ion secondary battery, M α Preferably, contains K, more preferably M α is K. M β is an element that provides a trivalent cation. Examples of elements that provide a trivalent cation include Al, Ga, In, Sc, Y, and La, with Al being preferred. Therefore, M β Preferably, M contains Al. γ is an element that provides a tetravalent cation. Examples of elements that provide a tetravalent cation include Si, Ge, and Sn, preferably Si and / or Ge, and more preferably Si. Therefore, M γ Preferably, M contains Si and / or Ge, more preferably Si. X is at least one selected from the group consisting of F, Cl, Br and I, and is preferably F. Therefore, it is preferable that X contains F. Particularly preferably, Mα contains Li, and M β contains Al, and M γ contains Si and X contains F. Therefore, Li ａ Al ｂ Si ｃ F ｄ It is particularly preferred that the solid electrolyte represented by the formula (I) has high lithium ion conductivity. With such a composition, a solid electrolyte having high lithium ion conductivity can be more reliably produced.

[0021] The solid electrolyte is (i) M α , M β and compounds containing X (e.g., Li ３ AlF ６ ) and M α ２ M γ X ６ (For example, Li ２ SiF ６ ), or (ii) a mixture with a compound represented by M β and a compound consisting of X (e.g., AlF ３ ) and M α and a compound consisting of X (e.g., LiF) and M α ２ M γ X ６ (For example, Li ２ SiF ６ ) and mechanical milling the mixture. In this way, a solid electrolyte with high ionic conductivity can be produced. Although the reason for this is not entirely clear, mechanical milling is thought to increase the ionic conductivity of M α In crystal structures containing M (e.g., Li), β (e.g., Al) and M γ (e.g., Si) and (e.g., Al ３＋ In contrast to Si ４＋ One possible reason is that the ZnO forms a solid solution.

[0022] When determining whether an unknown solid electrolyte is the above-mentioned solid electrolyte, chemical analysis is performed on the unknown solid electrolyte to determine whether the constituent elements are M α , M β , M γIt is sufficient to confirm whether the unknown solid electrolyte is of the above composition formula or not. In addition, to confirm whether the unknown solid electrolyte is of the above composition formula or not, for example, Li, Al, and Si can be quantified by an ICP-emission spectrometer. F can be quantified by an ion chromatograph. When the solid electrolyte contains elements other than Al, M, β When the element M β A measurement method capable of quantifying the above may be appropriately selected.

[0023] The solid electrolyte used in the present invention may be mixed with other substances (which may contain X, such as Li) and used as an electrolyte material. In this case, the solid electrolyte is preferably the component with the largest mass ratio among the components contained in the electrolyte material, i.e., the main component. The mass ratio of the main component in the electrolyte material is preferably 50 wt % or more, more preferably 60 wt % or more, and even more preferably 70 wt % or more.

[0024] As described above, in the battery 10 of the present invention, sulfide-free materials can be used for the positive electrode 12, the negative electrode 14, and the electrolyte layer 16. In other words, it is preferable that no part of the positive electrode 12, the negative electrode 14, or the electrolyte layer 16 contains sulfide. This prevents the generation of toxic gases such as hydrogen sulfide, making the battery 10 inherently safe.

[0025] The battery 10 preferably further includes a positive electrode current collector 18 and a negative electrode current collector 20. The positive electrode current collector 18 is preferably provided on the surface of the positive electrode 12 opposite the electrolyte layer 16, and the negative electrode current collector 20 is preferably provided on the surface of the negative electrode 14 opposite the electrolyte layer 16. Examples of materials that can be used to form the positive electrode current collector 18 and the negative electrode current collector 20 include aluminum (Al), copper (Cu), titanium (Ti), nickel (Ni), stainless steel (SUS), carbon, platinum (Pt), platinum (Pt) / palladium (Pd), gold (Au), silver (Ag), and ITO (indium-tin oxide).

[0026] The container 22 is not particularly limited as long as it can accommodate a single battery 10 or a stack of multiple batteries 10 stacked in series or parallel. In particular, when the battery 10 is an all-solid-state battery, a relatively simple container shape can be adopted for the container 22 because there is no concern about electrolyte leakage. For example, a chip shape for mounting on an electronic circuit or a laminate cell shape (e.g., a multi-layer product of aluminum (Al) / polypropylene (PP)) for thin and wide space applications can be adopted.

[0027] 2. Method for Producing Solid Electrolyte As an example of a preferred method for producing the above-mentioned solid electrolyte, ３ AlF ６ (hereinafter referred to as LAF) and Li ２ SiF ６ (hereinafter referred to as LSF) and then subjected to mechanical milling treatment.

[0028] First, LAF powder is prepared. For example, commercially available LiF (lithium fluoride) powder and commercially available AlF ３ (aluminum fluoride) powder and LiF:AlF ３ The components are weighed and mixed so that the molar ratio is 3:1. The resulting mixture is then heat-treated at a high temperature (e.g., 900°C) and pulverized to obtain LAF powder. LAF powder may also be produced by other methods.

[0029] On the other hand, LSF powder is prepared. Commercially available LSF powder may be used, but LSF powder may also be prepared by a known method.

[0030] Next, the LAF powder and the LSF powder are mixed to obtain a mixed powder, in which the proportion of the amount of LSF in the total amount of LAF and LSF is more than 0 mol % and less than 100 mol %, preferably 5 to 80 mol %, more preferably 5 to 60 mol %.

[0031] The mixed powder thus obtained is subjected to mechanical milling to obtain a solid electrolyte powder that can be used in the present invention. One example of mechanical milling is using a planetary ball mill. In a planetary ball mill, the pot rotates on its axis while the stage on which the pot is placed revolves, making it possible to generate very high impact energy. However, other types of grinders may also be used for mechanical milling. Mechanical milling may be performed at room temperature, but the temperature and other conditions may be changed as appropriate.

[0032] The present invention will be explained in more detail by the following examples, but the present invention is not limited to the following examples.

[0033] Example 1 (Comparison) (1) Preparation of LYC Solid Electrolyte Powder Commercially available LiCl powder and commercially available YCl powder were mixed in a glove box or dry room with a dew point of −40° C. or less. ３ The powder was dissolved in LiCl:YCl ３ The mixture was weighed and mixed in a molar ratio of 3:1, and subjected to mechanical milling using a planetary ball mill to obtain Li ３ Y １ Cl ６ Thus, an LYC solid electrolyte powder having the composition shown below was obtained.

[0034] (2) Preparation of Positive Electrode Sheet A positive electrode blend powder was obtained by weighing and mixing LYC solid electrolyte powder, lithium nickel cobalt manganese oxide (NCM) powder as a positive electrode active material, and carbon powder as a conductive additive in a volume ratio of LYC:NCM:carbon = 50:50:2. An organic binder and an organic solvent were added to the obtained positive electrode blend powder and kneaded, and a positive electrode sheet was prepared by the doctor blade method.

[0035] (3) Preparation of Negative Electrode Sheet A negative electrode blend was obtained by weighing and mixing LYC solid electrolyte powder, lithium titanate (LTO) powder as a negative electrode active material, and carbon powder as a conductive additive in a volume ratio of LYC:LTO:carbon = 50:50:2. An organic binder and an organic solvent were added to the obtained negative electrode blend powder and kneaded, and a negative electrode sheet was prepared by the doctor blade method.

[0036] (4) Preparation of Solid Electrolyte Sheet An organic binder and an organic solvent were added to the LYC solid electrolyte powder and kneaded, and a solid electrolyte sheet was prepared by a doctor blade method.

[0037] (5) Preparation of an all-solid-state battery The positive electrode sheet, negative electrode sheet, and solid electrolyte sheet were punched out with a punch to obtain positive electrode sheet pieces, negative electrode sheet pieces, and solid electrolyte sheet pieces, each with a diameter of 10 mm. The positive electrode sheet pieces, solid electrolyte sheet pieces, and negative electrode sheet pieces were placed in this order in a mold made of PEEK resin with an inner diameter of 10 mm, and the mold was sandwiched between a pair of stainless steel metal punches from above and below. In this state, the sheets were laminated and integrated by uniaxial pressing at a pressure of 150 MPa to obtain an all-solid-state battery.

[0038] (6) Evaluation of All-Solid-State Battery (Charge-Discharge Test) Conductors were connected to the top and bottom of a pair of metal punches, respectively, and the all-solid-state battery was placed in a thermostatic chamber at 100°C. A charge-discharge test of the all-solid-state battery was performed as follows. First, the all-solid-state battery was charged under the conditions of a charge cut-off voltage of 2.7 V, a CC charge current of 0.1 C, and a CV charge current of 0.01 C. That is, the battery was charged at a constant current (CC) rate of 0.1 C until a voltage of 2.7 V was reached, followed by constant voltage (CV) charging until the current value reached a 0.01 C rate. The all-solid-state battery thus charged was discharged under the conditions of a discharge cut-off voltage of 1.5 V, a CC discharge current of 0.1 C, and a CV discharge current of 0.01 C. That is, the battery was discharged at a constant current (CC) rate of 0.1 C until a voltage of 1.5 V was reached, followed by constant voltage (CV) discharging until the current value reached a 0.01 C rate. This series of charge-discharge operations constitutes one cycle. The coulombic efficiency at the first cycle was 45%, and the discharge capacity at the first cycle was 62 mAh / g per gram of positive electrode active material. The above charge / discharge cycle was repeated, and the coulombic efficiency and discharge capacity at the third cycle were measured. The coulombic efficiency at the third cycle was 93%. The discharge capacity at the third cycle was divided by the discharge capacity at the first cycle and multiplied by 100 to calculate the discharge capacity retention rate (i.e., cycle capacity retention rate), which was 67%. These results are shown in Table 1 and FIG. 2.

[0039] Example 2 An all-solid-state battery was fabricated and evaluated in the same manner as in Example 1, except that 1) LAF-LSF solid electrolyte powder was fabricated, evaluated, and used instead of LYC solid electrolyte powder as described below, and 2) the charge-discharge cycle was further repeated in the charge-discharge test, and the Coulombic efficiency and discharge capacity retention rate at the 10th cycle were also measured. The discharge capacity retention rate at the 10th cycle (i.e., cycle capacity retention rate) was calculated by dividing the discharge capacity at the 10th cycle by the discharge capacity at the 1st cycle and multiplying the result by 100. The results are shown in Table 1 and FIG. 3.

[0040] (Preparation of LAF-LSF Solid Electrolyte Powder) LAF-LSF solid electrolyte powder was prepared in a glove box or dry room with a dew point of −40° C. or less as follows. First, commercially available LiF powder and commercially available AlF ３ The powder was dissolved in LiF:AlF ３ The mixture was weighed and mixed in a molar ratio of 3:1, treated at 900°C in an Ar atmosphere, and then crushed in a mortar. ３ AlF ６ The LAF powder thus obtained was mixed with commercially available Li ２ SiF ６ powder and LAF(Li ３ AlF ６ ): Li ２ SiF ６ The mixture was weighed and mixed in a molar ratio of 8:2, and mechanical milling was carried out using a planetary ball mill to obtain Li ２．８ Al ０．８ Si ０．２ F ６．０ Thus, an LAF-LSF solid electrolyte powder having the following composition was obtained.

[0041] (Measurement of ionic conductivity) The LAF-LSF solid electrolyte powder was placed in a mold equipped with a PEEK (polyether ether ketone) resin sleeve and upper and lower stainless steel punches, and uniaxial press molding was performed under a pressure of 400 MPa. Conductors were connected to the upper and lower punches, respectively, and impedance measurements were performed at room temperature to calculate the ionic conductivity. As a result, the ionic conductivity of the LAF-LSF solid electrolyte was found to be 5×10 at room temperature. －６ The viscosity was 200 S / cm or more.

[0042] Example 3 An all-solid-state battery was produced and evaluated in the same manner as in Example 2, except that the temperature of the thermostatic chamber in the charge-discharge test was set to 150° C. The results are shown in Table 1.

[0043] Example 4 Except for using SiO powder as the negative electrode active material, an all-solid-state battery was produced and evaluated in the same manner as in Example 2. The results are shown in Table 1 and FIG.

[0044]

Claims

1. A positive electrode containing a positive electrode active material and a voltage of 0.1 V (vs. Li / Li ＋ ) or more, and an electrolyte layer disposed between the positive electrode and the negative electrode, wherein at least one of the positive electrode, the negative electrode, and the electrolyte layer is represented by the following composition formula: M α ａ M β ｂ M γ ｃ X ｄ (In the formula, M α is at least one selected from the group consisting of Li, Na and K, M β is an element that provides a trivalent cation, M γ is an element which provides a tetravalent cation, X is at least one selected from the group consisting of F, Cl, Br, and I, and a, b, c, and d satisfy the following: 0.9(3-x)≦a≦1.1(3-x), 0.9(1-x)≦b≦1.1(1-x), 0.9x≦c≦1.1x, 5.4≦d≦6.6, and 0<x<1.

2. The battery of claim 1, wherein each of the positive electrode, the negative electrode and the electrolyte layer comprises the solid electrolyte.

3. Said M α The battery of claim 1 or 2, wherein 4. Said M β The battery of claim 1 or 2, wherein comprises Al.

5. Said M γ The battery of claim 1 or 2, wherein comprises Si and / or Ge.

6. The battery of claim 1 or 2, wherein X comprises F.

7. Said M α contains Li, and the M β contains Al, and the M γ The battery of claim 1 or 2, wherein X comprises Si and F.

8. The solid electrolyte is Li ａ A ｂ S ｃ F ｄ The battery according to claim 1 or 2, wherein 9. The battery according to claim 1 or 2, wherein the positive electrode active material comprises at least one selected from the group consisting of lithium nickel manganese oxide (LNMO), lithium nickel cobalt manganese oxide (NCM), lithium cobalt oxide (LCO), lithium nickel cobalt aluminate (NCA), and lithium iron phosphate (LFP).

10. The negative electrode active material is lithium titanate (LTO), SiO, Si or a Si alloy, and TiO ２ The battery according to claim 1 or 2, comprising at least one selected from the group consisting of:

11. The battery of claim 1 or 2, wherein no portion of the positive electrode, the negative electrode, or the electrolyte layer contains sulfide.

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