Battery

Abstract

A battery 2000 according to the present disclosure comprises: a positive electrode 201; a negative electrode 203; and an electrolyte layer 202 positioned between the positive electrode 201 and the negative electrode 203. The positive electrode 201 contains a positive electrode material 1000. The positive electrode material 1000 contains a positive electrode active material 110 and a first solid electrolyte material 100. The positive electrode active material 110 contains LixMnyO2. Here, 0≤x≤1.05 and 0.9≤y≤1.1 are satisfied. The negative electrode 203 contains Bi as a main component of a negative electrode active material.

Description

Technical Field

[0001] This disclosure relates to batteries.

Background Art

[0002] Patent Document 1 discloses using, as a positive electrode active material, a product obtained by mixing and firing LiOH and MnO₂. In the examples of Patent Document 1, a battery using the positive electrode active material and a LiPb alloy as a negative electrode active material is disclosed.

[0003] Non-Patent Document 1 reveals that the product obtained by mixing and firing LiOH and MnO₂ is a composite of Li₂MnO₃ and MnO₂.

[0004] Patent Document 2 discloses an all-solid-state battery using a halide solid electrolyte.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Non-Patent Documents

[0006]

Non-Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] The battery disclosed herein is Positive electrode and, The negative electrode and, An electrolyte layer located between the positive electrode and the negative electrode, Equipped with, The positive electrode includes a positive electrode material, The positive electrode material comprises a positive electrode active material and a first solid electrolyte material. The positive electrode active material includes a material represented by the following composition formula (1): Li x Mn y O2...Equation (1) Here, 0≦x≦1.05 and 0.9≦y≦1.1 are satisfied. The aforementioned negative electrode contains Bi as the main component of the negative electrode active material. [Effects of the Invention]

[0009] According to this disclosure, Li x Mn y A novel, operable battery is provided, using O2 (0≦x≦1.05, 0.9≦y≦1.1) as the positive electrode active material and Bi as the negative electrode active material. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a cross-sectional view showing the schematic configuration of the battery 2000 in Embodiment 1. [Figure 2] Figure 2 is a cross-sectional view showing the schematic configuration of the battery 3000 in Embodiment 2. [Figure 3] Figure 3 is a graph showing the charge and discharge curves of the battery in Example 1. [Modes for carrying out the invention]

[0011] (Summary of one aspect of this disclosure) The battery according to the first aspect of the present disclosure is a positive electrode, a negative electrode, and an electrolyte layer positioned between the positive electrode and the negative electrode, and includes the positive electrode includes a positive electrode material, the positive electrode material includes a positive electrode active material and a first solid electrolyte material, the positive electrode active material includes a material represented by the following compositional formula (1), Li x Mn y O2 ··· Formula (1) where 0 ≦ x ≦ 1.05 and 0.9 ≦ y ≦ 1.1 are satisfied, the negative electrode includes Bi as a main component of the negative electrode active material.

[0012] According to the first aspect, a novel operable battery is provided in which Li x Mn y O2 (0 ≦ x ≦ 1.05, 0.9 ≦ y ≦ 1.1) is used as the positive electrode active material and Bi is used as the negative electrode active material.

[0013] In the second aspect of the present disclosure, for example, in the battery according to the first aspect, the compositional formula (1) may satisfy 0 ≦ x ≦ 1.

[0014] In the battery according to the second aspect, the positive electrode active material sufficiently occludes and releases Li.

[0015] In the third aspect of the present disclosure, for example, in the battery according to the second aspect, the compositional formula (1) may satisfy x = 1.

[0016] In the battery according to the third aspect, since the positive electrode active material more sufficiently occludes and releases Li, charge and discharge at a deep depth may be possible.

[0017] In the fourth aspect of the present disclosure, for example, in the battery according to any one of the first to third aspects, the compositional formula (1) may satisfy y = 1.

[0018] The battery according to the fourth embodiment may be capable of charging and discharging at greater depths because the positive electrode active material absorbs and releases Li more sufficiently.

[0019] In a fifth aspect of this disclosure, for example, in a battery according to any one of the first to fourth aspects, the negative electrode may include a material represented by the following composition formula (2). Li z Bi--- type (2) Here, z satisfies 0 ≤ z ≤ 3.

[0020] According to the fifth embodiment, the discharge flatness of the negative electrode is improved, and the battery operates more smoothly.

[0021] In a sixth aspect of this disclosure, for example, in the battery according to the fifth aspect, the composition formula (1) may satisfy x=0 and y=1, and the composition formula (2) may satisfy z=3.

[0022] In the sixth embodiment, the battery is configured such that Li is sufficiently absorbed and released at the positive and negative electrodes.

[0023] In a seventh aspect of this disclosure, for example, in a battery according to the fifth aspect, the composition formula (1) may satisfy x=1 and y=1, and the composition formula (2) may satisfy z=0.

[0024] In the battery according to the seventh embodiment, Li is sufficiently absorbed and released at the positive and negative electrodes.

[0025] In the eighth aspect of this disclosure, for example, in a battery according to any one of the first to seventh aspects, the negative electrode may include Bi elemental as the negative electrode active material.

[0026] The battery according to the eighth embodiment has an improved capacity.

[0027] In the ninth aspect of this disclosure, for example, in a battery according to any one of the first to eighth aspects, the negative electrode may be a plated layer.

[0028] The battery according to the ninth embodiment has an improved capacity.

[0029] In a tenth aspect of this disclosure, for example, in a battery according to any one of the first to ninth aspects, the first solid electrolyte material may include Li, at least one selected from the group consisting of metal elements other than Li and metalloid elements, and at least one selected from the group consisting of Cl and Br.

[0030] The battery according to the tenth embodiment has an improved capacity.

[0031] In the eleventh aspect of this disclosure, for example, in the battery according to the tenth aspect, the first solid electrolyte material may include a material represented by the following composition formula (3). Li α3 M β3 X γ3 ...Equation (3) Here, α3, β3, and γ3 are values ​​greater than 0, M is at least one element selected from the group consisting of metallic elements and metalloid elements other than Li, and X is at least one element selected from the group consisting of Cl and Br.

[0032] In the battery according to the 11th embodiment, the ionic conductivity of the first solid electrolyte material can be increased. This reduces the resistance caused by the movement of Li ions in the positive electrode material, and suppresses the increase in the internal resistance of the battery during charging.

[0033] In a twelfth aspect of this disclosure, for example, in the battery according to the eleventh aspect, the composition formula (3) is: 2.5 ≤ α3 ≤ 3, 1 ≤ β3 ≤ 1.1, γ3=6 It may satisfy the requirement.

[0034] In the battery according to the twelfth embodiment, the ionic conductivity of the first solid electrolyte material can be further increased. This makes it possible to further reduce the resistance caused by the movement of Li ions and to more effectively suppress the increase in the internal resistance of the battery during charging.

[0035] In a thirteenth aspect of this disclosure, for example, in a battery according to any one of the first to twelfth aspects, the electrolyte layer comprises a first electrolyte layer and a second electrolyte layer, wherein the first electrolyte layer is located between the positive electrode and the negative electrode, and the second electrolyte layer is located between the first electrolyte layer and the negative electrode.

[0036] The battery according to the 13th embodiment can suppress the increase in internal resistance during charging.

[0037] Embodiments of this disclosure will be described below with reference to the drawings. The following descriptions are general or specific examples. The numerical values, compositions, shapes, film thicknesses, electrical properties, battery structures, etc., shown below are examples and are not intended to limit this disclosure.

[0038] (Embodiment 1) Figure 1 is a cross-sectional view showing the schematic configuration of the battery 2000 in Embodiment 1 of the present disclosure.

[0039] The battery 2000 comprises a positive electrode 201, a negative electrode 203, and an electrolyte layer 202 located between the positive electrode 201 and the negative electrode 203. The positive electrode 201 includes a positive electrode material 1000. The positive electrode material 1000 includes a positive electrode active material 110 and a first solid electrolyte material 100. The positive electrode active material 110 includes a material represented by the following compositional formula (1). Li x Mn y O2...Equation (1) Here, the conditions 0 ≤ x ≤ 1.05 and 0.9 ≤ y ≤ 1.1 are satisfied.

[0040] Negative electrode 203 contains Bi as the main component of the negative electrode active material.

[0041] The statement "Negative electrode 203 contains Bi as the main component of the negative electrode active material" means that "in negative electrode 203, Bi is the component that is present in the largest molar ratio as the negative electrode active material."

[0042] The following describes the various components of the battery 2000 in this embodiment.

[0043] [Positive electrode 201] As described above, the positive electrode 201 has a positive electrode material 1000. The positive electrode material 1000 includes a positive electrode active material 110 and a first solid electrolyte material 100. The positive electrode active material 110 includes a material represented by the following compositional formula (1). Li x Mn y O2...Equation (1) Here, 0 ≤ x ≤ 1.05 and 0.9 ≤ y ≤ 1.1.

[0044] In empirical formula (1), the condition 0 ≤ x ≤ 1 may also be satisfied.

[0045] In empirical formula (1), x=1 may also be satisfied.

[0046] In composition formula (1), y=1 may be satisfied. That is, the positive electrode active material 110 may contain LiMnO2.

[0047] The material represented by composition formula (1) is inexpensive because it does not contain Co. With this configuration, the cost of the 2000 battery can be reduced.

[0048] The positive electrode active material 110 may consist only of the material represented by composition formula (1). The positive electrode active material 110 may consist only of LiMnO2.

[0049] The first solid electrolyte material 100 may include Li, at least one element selected from the group consisting of metal elements other than Li and metalloid elements, and at least one element selected from the group consisting of Cl and Br.

[0050] "Metallic elements" are B, Si, Ge, As, Sb, and Te.

[0051] "Metallic elements" refer to all elements in groups 1 through 12 of the periodic table, excluding hydrogen, as well as all elements in groups 13 through 16, excluding B, Si, Ge, As, Sb, Te, C, N, P, O, S, and Se. In other words, they are the elements that can form cations when forming halogen compounds and inorganic compounds.

[0052] With the above configuration, the positive electrode material 1000 has high oxidation resistance. Therefore, the increase in internal resistance during charging of the battery 2000 can be suppressed.

[0053] The first solid electrolyte material 100 may also be represented by the following compositional formula (3). Li α3 M β3 X γ3 ...Equation (3) Here, α3, β3, and γ3 are values ​​greater than 0, M is at least one element selected from the group consisting of metallic elements and metalloid elements other than Li, and X is at least one element selected from the group consisting of Cl and Br.

[0054] With the above configuration, the ionic conductivity of the first solid electrolyte material 100 can be further increased. This makes it possible to further reduce the resistance in the battery that is caused by the movement of Li ions in the positive electrode material 1000.

[0055] In compositional formula (3), M may contain Y. That is, the first solid electrolyte material 100 may contain Y as a metallic element.

[0056] With the above configuration, the ionic conductivity of the first solid electrolyte material 100 can be further increased. This makes it possible to further reduce the resistance in the battery that is caused by the movement of Li ions in the positive electrode material 1000.

[0057] In the compositional formula (3), 1 ≦ α3 ≦ 4, 0 < β3 ≦ 2, and 3 ≦ γ3 < 7 may be satisfied.

[0058] In the compositional formula (3), 2.5 ≦ α3 ≦ 3, 1 ≦ β3 ≦ 1.1, and γ3 = 6 may be satisfied.

[0059] According to the above configuration, the ionic conductivity of the first solid electrolyte material 100 can be further increased. Thereby, the resistance derived from the movement of Li ions in the positive electrode material 1000 can be further reduced.

[0060] The first solid electrolyte material 100 containing Y is, for example, Li a Me b Y c It may be a compound represented by the compositional formula of X6. Here, a + m'b + 3c = 6 and c > 0 are satisfied. Me is at least one element selected from the group consisting of metal elements and semi-metal elements excluding Li and Y. Also, m' is the valence of Me.

[0061] As Me, at least one element selected from the group consisting of Mg, Ca, Sr, Ba, Zn, Sc, Al, Ga, Bi, Zr, Hf, Ti, Sn, Ta, and Nb may be used.

[0062] According to the above configuration, the ionic conductivity of the first solid electrolyte material 100 can be further increased. Thereby, the resistance derived from the movement of Li ions in the positive electrode material 1000 in the battery can be further reduced.

[0063] The first solid electrolyte material 100 may be a material represented by the following compositional formula (A1). Li 6-3d Y d X6 ··· Formula (A1) Here, in the compositional formula (A1), X is a halogen element and contains Cl. Also, 0 < d < 2 is satisfied.

[0064] With the above configuration, the ionic conductivity of the first solid electrolyte material 100 can be further increased. This makes it possible to further reduce the resistance caused by the movement of Li ions in the positive electrode material 1000.

[0065] The first solid electrolyte material 100 may be a material represented by the following compositional formula (A2). Li3YX6...Formula (A2) Here, in the composition formula (A2), X is a halogen element and also contains Cl.

[0066] With the above configuration, the ionic conductivity of the first solid electrolyte material 100 can be further increased. This makes it possible to further reduce the resistance caused by the movement of Li ions in the positive electrode material 1000 in the battery.

[0067] The first solid electrolyte material 100 may contain Li3YBr2Cl4.

[0068] The first solid electrolyte material 100 may be a material represented by the following compositional formula (A3). Li 3-3δ Y 1+δ Cl6...Formula (A3) Here, in empirical formula (A3), the condition 0 < δ ≤ 0.15 is satisfied.

[0069] With the above configuration, the ionic conductivity of the first solid electrolyte material 100 can be further increased. This makes it possible to further reduce the resistance caused by the movement of Li ions in the positive electrode material 1000 in the battery.

[0070] The first solid electrolyte material 100 may be a material represented by the following compositional formula (A4). Li 3-3δ+a4 Y 1+δ-a4 Me a4 Cl 6-x4 Br x4 ...Formula (A4) Here, in the compositional formula (A4), Me is at least one element selected from the group consisting of Mg, Ca, Sr, Ba, and Zn. Also, -1 < δ < 2, 0 < a4 < 3, 0 < (3 - 3δ + a4), 0 < (1 + δ - a4), and 0 ≤ x4 < 6 are satisfied.

[0071] According to the above configuration, the ionic conductivity of the first solid electrolyte material 100 can be further increased. As a result, the resistance derived from the movement of Li ions in the positive electrode material 1000 in the battery can be further reduced.

[0072] The first solid electrolyte material 100 may be a material represented by the following compositional formula (A5). Li 3-3δ Y 1+δ-a5 Me a5 Cl 6-x5 Br x5 ··· Formula (A5) Here, in the compositional formula (A5), Me is at least one element selected from the group consisting of Al, Sc, Ga, and Bi. Also, -1 < δ < 1, 0 < a5 < 2, 0 < (1 + δ - a5), and 0 ≤ x5 < 6 are satisfied.

[0073] According to the above configuration, the ionic conductivity of the first solid electrolyte material 100 can be further increased. As a result, the resistance derived from the movement of Li ions in the positive electrode material 1000 can be further reduced.

[0074] The first solid electrolyte material 100 may be a material represented by the following compositional formula (A6). Li 3-3δ-a6 Y 1+δ-a6 Me a6 Cl 6-x6 Br x6 ··· Formula (A6) Here, in the compositional formula (A6), Me is at least one element selected from the group consisting of Zr, Hf, and Ti. Also, -1 < δ < 1, 0 < a6 < 1.5, 0 < (3 - 3δ - a6), 0 < (1 + δ - a6), and 0 ≤ x6 < 6 are satisfied.

[0075] The first solid electrolyte material 100 may be a material represented by the following compositional formula (A7). Li 3-3δ-2a7 Y 1+δ-a7 Me a7 C l6-x7 Br x7 ··· Formula (A7) Here, in the compositional formula (A7), Me is at least one element selected from the group consisting of Ta and Nb. Also, -1 < δ < 1, 0 < a7 < 1.2, 0 < (3 - 3δ - 2a7), 0 < (1 + δ - a7), and 0 ≦ x7 < 6 are satisfied.

[0076] As the first solid electrolyte material 100, for example, Li3YX6, Li2MgX4, Li2FeX4, Li(Al, Ga, In)X4, Li3(Al, Ga, In)X6, etc. can be used. Here, X contains Cl. In the present disclosure, when an element in a formula is represented as "(Al, Ga, In)", this notation indicates at least one element selected from the group of elements within the parentheses. That is, "(Al, Ga, In)" is synonymous with "at least one selected from the group consisting of Al, Ga, and In". The same applies to other elements. Note that the first solid electrolyte material 100 may not contain sulfur.

[0077] The first solid electrolyte material 100 may contain a sulfide solid electrolyte. As the sulfide solid electrolyte, for example, Li2S - P2S5, Li2S - SiS2, Li2S - B2S3, Li2S - GeS2, Li 3.25 Ge 0.25 P 0.75 S4, Li 10 GeP2S 12 , Li6PS5Cl, etc. can be used. Also, to these, LiX, Li2O, MO q , Li p MO qThe following may be added: Here, X is at least one element selected from the group consisting of F, Cl, Br, and I. M is at least one element selected from the group consisting of P, Si, Ge, B, Al, Ga, In, Fe, and Zn. p and q are each independently natural numbers.

[0078] The first solid electrolyte material 100 may contain lithium sulfide and phosphorus sulfide. The sulfide solid electrolyte may be at least one selected from the group consisting of Li2S-P2S5 and Li6PS5Cl.

[0079] The shape of the first solid electrolyte material 100 is not particularly limited. If the first solid electrolyte material 100 is a powder material, its shape may be, for example, needle-shaped, spherical, ellipsoidal, etc. For example, the shape of the first solid electrolyte material 100 may be particulate.

[0080] For example, if the shape of the first solid electrolyte material 100 is particulate (e.g., spherical), the median diameter of the first solid electrolyte material 100 may be 100 μm or less. When the median diameter of the first solid electrolyte material 100 is 100 μm or less, the positive electrode active material 110 and the first solid electrolyte material 100 can form a good dispersion state in the positive electrode material 1000. As a result, the charge and discharge characteristics of the battery 2000 are improved.

[0081] The median diameter of the first solid electrolyte material 100 may be 10 μm or less. With the above configuration, the positive electrode active material 110 and the first solid electrolyte material 100 can form a good dispersion state in the positive electrode material 1000.

[0082] In Embodiment 1, the median diameter of the first solid electrolyte material 100 may be smaller than the median diameter of the positive electrode active material 110. With the above configuration, the first solid electrolyte material 100 and the positive electrode active material 110 can form a better dispersion state in the positive electrode.

[0083] The median diameter of the positive electrode active material 110 may be 0.1 μm or more and 100 μm or less.

[0084] When the median diameter of the positive electrode active material 110 is 0.1 μm or more, the positive electrode active material 110 and the first solid electrolyte material 100 can form a good dispersion state in the positive electrode material 1000. Therefore, the charge and discharge characteristics of the battery using the positive electrode material 1000 are improved. When the median diameter of the positive electrode active material 110 is 100 μm or less, the lithium diffusion rate within the positive electrode active material 110 is improved. Therefore, the battery 2000 can operate at high power.

[0085] The median diameter of the positive electrode active material 110 may be larger than the median diameter of the first solid electrolyte material 100. This allows the positive electrode active material 110 and the first solid electrolyte material 100 to form a good dispersion state.

[0086] In this disclosure, “median diameter” means the particle size at which the cumulative volume in the volume-based particle size distribution is equal to 50%. The volume-based particle size distribution is measured, for example, by a laser diffraction analyzer or an image analyzer.

[0087] The positive electrode material 1000 may further contain other positive electrode active materials besides the positive electrode active material 110.

[0088] The positive electrode active material includes a material having the property of intercalating and releasing metal ions (e.g., lithium ions). Other positive electrode active materials besides the positive electrode active material 110 include, for example, lithium-containing transition metal oxides, transition metal fluorides, polyanionic materials, fluorinated polyanionic materials, transition metal sulfides, transition metal oxysulfides, or transition metal oxynitrides. Examples of lithium-containing transition metal oxides include Li(Ni,Co,Al)O2, Li(Ni,Co,Mn)O2, and LiCoO2. In particular, using lithium-containing transition metal oxides can reduce the manufacturing cost of the positive electrode material 1000 and increase the average discharge voltage.

[0089] The positive electrode material 1000 in the battery 2000 of Embodiment 1 may include a plurality of first solid electrolyte materials 100 and a plurality of positive electrode active materials 110.

[0090] The content of the first solid electrolyte material 100 and the content of the positive electrode active material 110 in the positive electrode material 1000 may be the same or different.

[0091] In the positive electrode material 1000, as shown in Figure 1, the first solid electrolyte material 100 and the positive electrode active material 110 may be in contact with each other.

[0092] The volume ratio "v1:100-v1" of the positive electrode active material 110 and the first solid electrolyte material 100 contained in the positive electrode 201 may satisfy the condition 30≦v1≦98. Here, v1 represents the volume ratio of the positive electrode active material 110 when the total volume of the positive electrode active material 110 and the first solid electrolyte material 100 contained in the positive electrode 201 is set to 100. If 30≦v1 is satisfied, a sufficient energy density of the battery can be ensured. If v1≦98 is satisfied, the battery 2000 can operate at high power.

[0093] The positive electrode active material 110 may have at least a portion of its surface covered by a coating material.

[0094] Coating materials include sulfide solid electrolytes, oxide solid electrolytes, and halide solid electrolytes. The sulfide solid electrolyte used in the coating material may be the same material as exemplified in the first solid electrolyte material 100. Oxide solid electrolytes used in the coating material include Li-Nb-O compounds such as LiNbO3, Li-BO compounds such as LiBO2 and Li3BO3, Li-Al-O compounds such as LiAlO2, Li-Si-O compounds such as Li4SiO4, Li2SO4, and Li4Ti5O 12 Examples include Li-Ti-O compounds such as Li2ZrO3, Li-Zr-O compounds such as Li2MoO3, Li-Mo-O compounds such as LiV2O5, Li-WO compounds such as Li2WO4, and Li-PO compounds such as Li3PO4. The halide solid electrolyte does not need to contain sulfur.

[0095] The thickness of the positive electrode 201 may be 10 μm or more and 500 μm or less. If the thickness of the positive electrode 201 is 10 μm or more, sufficient energy density of the battery can be ensured. If the thickness of the positive electrode 201 is 500 μm or less, the battery 2000 can operate at high power.

[0096] [Electrolyte layer 202] The electrolyte layer 202 is placed between the positive electrode 201 and the negative electrode 203.

[0097] The electrolyte layer 202 contains an electrolyte material. This electrolyte material is, for example, a solid electrolyte material. The electrolyte layer 202 may also be a solid electrolyte layer.

[0098] The same material as the first solid electrolyte material 100 may be used as the solid electrolyte material contained in the electrolyte layer 202. In other words, the electrolyte layer 202 may contain the same material as the first solid electrolyte material 100.

[0099] As the solid electrolyte material contained in the electrolyte layer 202, a halogen solid electrolyte, a sulfide solid electrolyte, an oxide solid electrolyte, a polymer solid electrolyte, or a complex hydride solid electrolyte may be used.

[0100] Examples of oxide solid electrolytes included in the electrolyte layer 202 include NASICON-type solid electrolytes such as LiTi2(PO4)3 and its elemental substitutions, (LaLi)TiO3-based perovskite-type solid electrolytes, and Li 14 ZnGe4O 16 , LiSICON-type solid electrolytes such as Li4SiO4, LiGeO4 and their elemental substitutions, Li7La3Zr2O 12 Garnet-type solid electrolytes, such as those represented by elemental substitutions thereof, Li3PO4 and its N-substituted counterparts, and glass or glass ceramics based on Li-BO compounds such as LiBO2 and Li3BO3, with Li2SO4, Li2CO3, etc., added, can be used.

[0101] As the polymer solid electrolyte contained in the electrolyte layer 202, for example, a compound of a polymer compound and a lithium salt can be used. The polymer compound may have an ethylene oxide structure. Polymer compounds having an ethylene oxide structure can contain a large amount of lithium salt. Therefore, the ionic conductivity can be further increased. Examples of lithium salts that can be used include LiPF6, LiBF4, LiSbF6, LiAsF6, LiSO3CF3, LiN(SOCF3)2, LiN(SO2C2F5)2, LiN(SO2CF3)(SO2C4F9), and LiC(SO2CF3)3. One lithium salt selected from the exemplified lithium salts can be used alone. Alternatively, a mixture of two or more lithium salts selected from the exemplified lithium salts can be used.

[0102] Examples of complex hydride solid electrolytes that can be included in the electrolyte layer 202 include LiBH4-LiI and LiBH4-P2S5.

[0103] The electrolyte layer 202 may contain a solid electrolyte material as its main component. That is, the electrolyte layer 202 may contain a solid electrolyte material in an amount of 50% or more (i.e., 50% by mass or more) of the total mass of the electrolyte layer 202.

[0104] With the above configuration, the charge and discharge characteristics of the battery 2000 can be improved.

[0105] The electrolyte layer 202 may contain a solid electrolyte material in an amount of 70% or more by mass relative to the total electrolyte layer 202 (i.e., 70% by mass or more).

[0106] With the above configuration, the charge and discharge characteristics of the battery 2000 can be further improved.

[0107] The electrolyte layer 202 mainly contains a solid electrolyte material, but may also contain unavoidable impurities, or starting materials, by-products, and decomposition products used in the synthesis of the solid electrolyte material.

[0108] The electrolyte layer 202 may contain solid electrolyte material in a mass ratio of 100% (i.e., 100% by mass) of the total electrolyte layer 202, for example, excluding impurities that are unavoidable to be present.

[0109] With the above configuration, the charge and discharge characteristics of the battery 2000 can be further improved.

[0110] As described above, the electrolyte layer 202 may be composed solely of solid electrolyte material.

[0111] The electrolyte layer 202 may contain two or more of the materials listed as solid electrolyte materials. For example, the electrolyte layer 202 may contain a halide solid electrolyte and a sulfide solid electrolyte.

[0112] The thickness of the electrolyte layer 202 may be 1 μm or more and 300 μm or less. If the thickness of the electrolyte layer 202 is 1 μm or more, short circuits between the positive electrode 201 and the negative electrode 203 become less likely. If the thickness of the electrolyte layer 202 is 300 μm or less, the battery 2000 can operate at high output.

[0113] Although this explanation primarily describes the case where the electrolyte layer 202 is a solid electrolyte layer containing a solid electrolyte material, the electrolyte material contained in the electrolyte layer 202 may also be an electrolyte solution. For example, the electrolyte layer 202 may consist of a separator and an electrolyte solution impregnated into the separator.

[0114] [Negative electrode 203] The negative electrode 203 contains a material having the property of intercalating and releasing metal ions (e.g., lithium ions). That is, the negative electrode 203 contains a negative electrode active material. The negative electrode 203 contains Bi as the main component of the negative electrode active material.

[0115] Unlike tin, for example, Bi does not have the property of having significantly different electrical potentials between the various compounds it forms with lithium. Therefore, electrodes containing Bi as an active material exhibit excellent discharge flatness.

[0116] Bi is an active material that intercepts and releases lithium ions at 0.8V relative to lithium. Bi is a metal that alloys with lithium. During charging, lithium is intercepted by Bi forming an alloy with lithium. That is, a lithium-bismuth alloy is formed in the negative electrode 203 when the battery 2000 is charged. The formed lithium-bismuth alloy includes, for example, at least one selected from the group consisting of LiBi and Li3Bi. That is, when the battery 2000 is charged, the negative electrode 203 includes, for example, at least one selected from the group consisting of LiBi and Li3Bi. When the battery 2000 is discharged, lithium is released from the lithium-bismuth alloy, and the lithium-bismuth alloy returns to Bi.

[0117] The negative electrode 203 may contain a material represented by the following composition formula (2). Li z Bi--- type (2) Here, z satisfies 0 ≤ z ≤ 3.

[0118] When x=0 and y=1 are satisfied in composition formula (1), z=3 may also be satisfied in composition formula (2). That is, when the positive electrode active material 110 contains MnO2, the negative electrode 203 may contain Li3Bi.

[0119] When x=1 and y=1 are satisfied in composition formula (1), z=0 may also be satisfied in composition formula (2). That is, when the positive electrode active material 110 contains LiMnO2, the negative electrode 203 may contain Bi.

[0120] In compositional formula (2), z=1 may be satisfied, or z=3 may be satisfied. The negative electrode 203 may include at least one selected from the group consisting of LiBi and Li3Bi.

[0121] The negative electrode 203 may contain elemental Bi as the negative electrode active material.

[0122] The negative electrode 203 may contain only elemental Bi as the negative electrode active material.

[0123] The negative electrode 203 may contain materials other than Bi as the negative electrode active material.

[0124] The negative electrode active material may be a metallic material, a carbon material, an oxide, a nitride, a tin compound, or a silicon compound. The metallic material may be a pure metal or an alloy. Examples of metallic materials include lithium metal or lithium alloys. Examples of carbon materials include natural graphite, coke, carbon in the process of graphitization, carbon fibers, spheroidal carbon, artificial graphite, or amorphous carbon. From the viewpoint of capacity density, silicon, tin, silicon compounds, or tin compounds may be used.

[0125] The negative electrode 203 does not necessarily have to contain an electrolyte. For example, the negative electrode 203 may be a layer made of the material represented by composition formula (2).

[0126] The negative electrode 203 may be in the form of a thin film.

[0127] The negative electrode 203 may be a plated layer.

[0128] The negative electrode 203 may be a plated layer formed by the deposition of Bi by plating.

[0129] The thickness of the negative electrode 203 is not particularly limited and may be, for example, 1 μm or more and 500 μm or less. For example, if the negative electrode 203 is a plated layer formed by depositing Bi by plating, the thickness of the negative electrode 203 may be, for example, 1 μm or more and 100 μm or less. When the thickness of the negative electrode 203 is 1 μm or more, a sufficient energy density of the battery 2000 can be ensured. When the thickness of the negative electrode 203 is 500 μm or less, the battery 2000 can operate at high power.

[0130] The negative electrode 203 may further contain a conductive material. Examples of conductive materials include carbon materials, metals, inorganic compounds, and conductive polymers. Examples of carbon materials include graphite, acetylene black, carbon black, Ketjen black, carbon whiskers, needle coke, and carbon fibers. Examples of graphite include natural graphite and artificial graphite. Examples of natural graphite include lump graphite and flake graphite. Examples of metals include copper, nickel, aluminum, silver, and gold. Examples of inorganic compounds include tungsten carbide, titanium carbide, tantalum carbide, molybdenum carbide, titanium boride, and titanium nitride. These materials may be used individually or in combination.

[0131] In the battery 2000 of Embodiment 1, a current collector electrically connected to the positive electrode 201 or the negative electrode 203 may be provided. That is, the battery 2000 may further include a positive electrode current collector and a negative electrode current collector.

[0132] The negative electrode 203 may be positioned in direct contact with the surface of the negative electrode current collector.

[0133] The negative electrode 203 may be a plated layer formed by depositing Bi on the negative electrode current collector by plating. The negative electrode 203 may also be a Bi plated layer provided in direct contact with the surface of the negative electrode current collector.

[0134] If the negative electrode 203 is a plating layer that is in direct contact with the surface of the negative electrode current collector, the negative electrode 203 adheres closely to the negative electrode current collector. This suppresses the deterioration of the current collection characteristics of the negative electrode 203 that occurs when the negative electrode 203 repeatedly expands and contracts. Therefore, the charge and discharge characteristics of the battery 2000 are further improved. Furthermore, if the negative electrode 203 is a plating layer, the negative electrode 203 contains Bi, which is the active material, at a high density, so even higher capacity can be achieved.

[0135] The material of the negative electrode current collector is, for example, a single metal or alloy. More specifically, it may be a single metal or alloy containing at least one selected from the group consisting of copper, chromium, nickel, titanium, platinum, gold, aluminum, tungsten, iron, and molybdenum. The current collector may also be stainless steel. These materials can also be used as the material for the positive electrode current collector.

[0136] The negative electrode current collector may contain copper (Cu).

[0137] From the viewpoint of easily ensuring high conductivity, the negative electrode current collector may be a metal foil, or a metal foil containing copper. Examples of copper-containing metal foils include copper foil and copper alloy foil. The copper content in the metal foil may be 50% by mass or more, or 80% by mass or more. In particular, the metal foil may be a copper foil containing substantially only copper as the metal.

[0138] At least one selected from the group consisting of a positive electrode 201, an electrolyte layer 202, and a negative electrode 203 may contain a binder for the purpose of improving the adhesion between particles. The binder is used to improve the bonding properties of the materials constituting the electrode. Examples of binders include polyvinylidene fluoride, polytetrafluoroethylene, polyethylene, polypropylene, aramid resin, polyamide, polyimide, polyamideimide, polyacrylonitrile, polyacrylic acid, polymethyl polyacrylate, polyethyl polyacrylate, polyhexyl polyacrylate, polymethacrylic acid, polymethyl polymethacrylate, polyethyl polymethacrylate, polyhexyl polymethacrylate, polyvinyl acetate, polyvinylpyrrolidone, polyether, polyethersulfone, hexafluoropolypropylene, styrene-butadiene rubber, and carboxymethylcellulose. Furthermore, a copolymer of two or more materials selected from the group consisting of tetrafluoroethylene, hexafluoroethylene, hexafluoropropylene, perfluoroalkyl vinyl ether, vinylidene fluoride, chlorotrifluoroethylene, ethylene, propylene, pentafluoropropylene, fluoromethyl vinyl ether, acrylic acid, and hexadiene may be used as a binder. Alternatively, a mixture of two or more materials selected from these may be used.

[0139] At least one of the positive electrode 201 and the negative electrode 203 may contain a conductive additive for the purpose of enhancing electronic conductivity. Examples of conductive additives include graphites such as natural graphite or artificial graphite, carbon blacks such as acetylene black and Ketjenblack, conductive fibers such as carbon fibers and metal fibers, metal powders such as carbon fluoride and aluminum, conductive whiskers such as zinc oxide and potassium titanate, conductive metal oxides such as titanium oxide, and conductive polymer compounds such as polyaniline, polypyrrole, and polythiophene. When a carbon conductive additive is used as the conductive additive, costs can be reduced.

[0140] Examples of the shapes of the battery 2000 in Embodiment 1 include coin-shaped, cylindrical, rectangular, sheet-shaped, button-shaped, flat, and stacked types.

[0141] The battery 2000 in Embodiment 1 may be manufactured, for example, by preparing a material for forming a positive electrode, a material for forming an electrolyte layer, and a material for forming a negative electrode, and then creating a laminate in which the positive electrode, electrolyte layer, and negative electrode are arranged in that order using a known method.

[0142] (Embodiment 2) Embodiment 2 will be described below. Descriptions that overlap with Embodiment 1 will be omitted as appropriate.

[0143] Figure 2 is a cross-sectional view showing the schematic configuration of the battery 3000 in Embodiment 2.

[0144] The battery 3000 in Embodiment 2 comprises a positive electrode 201, an electrolyte layer 202, and a negative electrode 203. The electrolyte layer 202 is disposed between the positive electrode 201 and the negative electrode 203. The electrolyte layer 202 includes a first electrolyte layer 301 and a second electrolyte layer 302. The first electrolyte layer 301 is located between the positive electrode 201 and the negative electrode 203, and the second electrolyte layer 302 is located between the first electrolyte layer 301 and the negative electrode 203. Figure 2 shows an example configuration of the battery 3000 in which the first electrolyte layer 301 is in contact with the positive electrode 201 and the second electrolyte layer 302 is in contact with the negative electrode 203.

[0145] With the above configuration, the increase in the internal resistance of the battery 3000 during charging can be suppressed.

[0146] The first electrolyte layer 301 and the second electrolyte layer 302 may be solid electrolyte layers.

[0147] From the viewpoint of the reduction resistance of the solid electrolyte material, the reduction potential of the solid electrolyte material contained in the second electrolyte layer 302 may be lower than the reduction potential of the solid electrolyte material contained in the first electrolyte layer 301. With the above configuration, the solid electrolyte material contained in the first electrolyte layer 301 can be used without reduction. This makes it possible to improve the charge and discharge efficiency of the battery 3000.

[0148] For example, the second electrolyte layer 302 may contain a sulfide solid electrolyte. Here, the reduction potential of the sulfide solid electrolyte contained in the second electrolyte layer 302 is lower than the reduction potential of the solid electrolyte material contained in the first electrolyte layer 301. With this configuration, the solid electrolyte material contained in the first electrolyte layer 301 can be used without reduction. This makes it possible to improve the charge and discharge efficiency of the battery 3000.

[0149] The thickness of the first electrolyte layer 301 and the second electrolyte layer 302 may be 1 μm or more and 300 μm or less. When the thickness of the first electrolyte layer 301 and the second electrolyte layer 302 is 1 μm or more, short circuits between the positive electrode 201 and the negative electrode 203 become less likely. When the thickness of the first electrolyte layer 301 and the second electrolyte layer 302 is 300 μm or less, the battery 3000 can operate at high output. [Examples]

[0150] The present disclosure will be described in more detail below with reference to examples.

[0151] <Example 1> [Preparation of the first solid electrolyte material] In an argon atmosphere, the raw material powders LiBr, YBr3, LiCl, and YCl3 were weighed in a molar ratio of LiBr:YBr3:LiCl:YCl3 = 1:1:5:1. Then, using a planetary ball mill (Fritsch, P-7 type), the mixture was milled at 600 rpm for 25 hours to obtain Li3YBr2Cl4 powder as the first solid electrolyte material.

[0152] [Fabrication of positive electrode active material] Benzophenone and methyl ethyl carbonate were mixed to prepare a mixed solution. The concentration of benzophenone in the mixed solution was 1 mol / liter. Lithium metal was dissolved in the mixed solution to saturation to prepare a lithium solution. The concentration of lithium in the lithium solution was 1 mol / liter. The prepared lithium solution was immersed in γ-β-MnO2 for 1.8 days. Then, the lithium solution was removed, washed with methyl ethyl carbonate, and vacuum dried to obtain the positive electrode active material Li x Mn y O2(0 < x ≦ 1.05, 0.9 ≦ y ≦ 1.1).

[0153] [Fabrication of Positive Electrode Material] The prepared positive electrode active material, the first solid electrolyte material, and vapor-grown carbon fiber (VGCF (manufactured by Showa Denko K.K.)) as a conductive assistant were weighed so that the mass ratio of the positive electrode active material: the first solid electrolyte material: VGCF was 27.75:64.75:7.5, and mixed in a mortar to fabricate the positive electrode material of Example 1. Note that VGCF is a registered trademark of Showa Denko K.K.

[0154] [Fabrication of Negative Electrode] As a pretreatment, a copper foil (10 cm × 10 cm, thickness: 10 μm) was pre-degreased with an organic solvent, then one side was masked and immersed in an acidic solvent for degreasing to activate the copper foil surface. Bismuth methanesulfonate as a soluble bismuth salt was added to 1.0 mol / L methanesulfonic acid so that the Bi 3+ ion concentration became 0.18 mol / L to prepare a plating bath. The activated copper foil was connected to a power source so that current could be applied, and then immersed in the plating bath. Then, by controlling the current density to 2 A / dm 2 Bi was electroplated to a thickness of approximately 3 μm on the surface of the unmasked copper foil. After electroplating, the copper foil was recovered from the acidic bath, the masking was removed, and then washed and dried with pure water. Then, by punching out to a size of φ0.92 cm, a negative electrode which is a plated layer deposited on the current collector was obtained.

[0155] [Fabrication of Battery] The battery for Example 1 was fabricated using the following procedure.

[0156] First, 480 mg of Li3YBr2Cl was placed inside an insulating outer cylinder and molded under pressure at 2 MPa. Then, 12.0 mg of positive electrode material was placed inside and molded under pressure at 2 MPa. This resulted in a laminate consisting of a positive electrode and a solid electrolyte layer.

[0157] Next, the negative electrode was laminated on the side of the solid electrolyte layer opposite to the side in contact with the positive electrode, with the Bi-plated surface facing the solid electrolyte layer. This was then pressure-molded at a pressure of 720 MPa to produce a laminate consisting of the positive electrode, solid electrolyte layer, and negative electrode.

[0158] Next, stainless steel current collectors were placed above and below the laminate, and current collection leads were attached to the current collectors.

[0159] Finally, the battery was fabricated by using an insulating ferrule to isolate and seal the inside of the insulating outer casing from the outside atmosphere.

[0160] Based on the above, the battery of Example 1 described above was fabricated.

[0161] [Charging test] A charging test was conducted using the battery from Example 1 described above, under the following conditions.

[0162] The battery was placed in a constant temperature bath at 85°C.

[0163] The battery was charged with a constant current of 33 μA, which corresponds to a rate of 0.05 C (20-hour rate) relative to its theoretical capacity. The charging termination voltage was set to 3.5 V. Next, the discharge termination voltage was set to 0.5 V, and the battery was discharged with a constant current.

[0164] Figure 3 is a graph showing the charge and discharge curves of the battery in Example 1. As shown in Figure 3, the battery in Example 1 was charged and discharged. [Industrial applicability]

[0165] The battery described herein can be used, for example, as an all-solid-state lithium-ion secondary battery.

Claims

1. Positive electrode and, The negative electrode and, An electrolyte layer located between the positive electrode and the negative electrode, Equipped with, The positive electrode includes a positive electrode material, The positive electrode material comprises a positive electrode active material and a first solid electrolyte material. The positive electrode active material comprises a material represented by the following compositional formula (1), Li x Mn y O 2 ... Formula (1) Here, 0 ≤ x ≤ 1.05 and 0.9 ≤ y ≤ 1.1 are satisfied. The aforementioned negative electrode contains Bi as the main component of the negative electrode active material. The negative electrode is a plating layer containing Bi elemental as the negative electrode active material. battery.

2. The above compositional formula (1) satisfies 0 ≤ x ≤ 1, The battery according to claim 1.

3. The aforementioned empirical formula (1) satisfies x = 1, The battery according to claim 2.

4. The aforementioned empirical formula (1) satisfies y = 1. The battery according to claim 1.

5. The aforementioned negative electrode comprises a material represented by the following composition formula (2): The battery according to claim 1. Li z Bi・・・Formula (2) Here, z satisfies 0 ≤ z ≤ 3.

6. The aforementioned compositional formula (1) satisfies x = 0 and y = 1, and the aforementioned compositional formula (2) satisfies z = 3. The battery according to claim 5.

7. The aforementioned compositional formula (1) satisfies x = 1 and y = 1, and the aforementioned compositional formula (2) satisfies z = 0. The battery according to claim 5.

8. The first solid electrolyte material comprises Li, at least one element selected from the group consisting of metal elements and metalloid elements other than Li, and at least one element selected from the group consisting of Cl and Br. The battery according to claim 1.

9. The first solid electrolyte material includes a material represented by the following compositional formula (3): The battery according to claim 8. Li α3 M β3 X γ3 ... Equation (3) Here, α3, β3, and γ3 are values ​​greater than 0. M is at least one element selected from the group consisting of metallic elements and metalloid elements other than Li. X is at least one element selected from the group consisting of Cl and Br.

10. The aforementioned composition formula (3) is, ２．５≦α３≦３、 １≦β３≦１．１、 γ3 = 6 Satisfying The battery according to claim 9.

11. The electrolyte layer includes a first electrolyte layer and a second electrolyte layer. The first electrolyte layer is located between the positive electrode and the negative electrode. The second electrolyte layer is located between the first electrolyte layer and the negative electrode. The battery according to claim 1.

Images