Battery

Abstract

A battery 2000 according to the present disclosure comprises a positive electrode 201, a negative electrode 203, and an electrolyte layer 202 that is 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 111. The positive electrode active material 110 contains oxides comprising Li, Ni, Mn, and O. The first solid electrolyte material 111 contains 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 F, Cl, and Br. The negative electrode 203 contains Bi as a principal component of a negative electrode active material.

Description

[Technical Field]

[0001] This disclosure relates to batteries. [Background technology]

[0002] Patent Document 1 discloses an all-solid-state secondary battery containing a solid electrolyte made of a compound containing indium as a cation and a halogen element as an anion. In this all-solid-state secondary battery, it is desirable that the Li-to-Potential of the positive electrode active material be 3.9V or less on average, as this suppresses the formation of a film made of decomposition products due to oxidative decomposition of the solid electrolyte, thereby obtaining good charge-discharge characteristics. Furthermore, LiCoO2 or LiNi is used as the positive electrode active material with an Li-to-Potential of 3.9V or less on average. 0.8 Co 0.15 Al 0.05 A layered transition metal oxide cathode such as O2 is disclosed. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2006-244734 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] This disclosure provides a novel, operable battery using a positive electrode active material comprising an oxide composed of Li, Ni, Mn, and O. [Means for solving the problem]

[0005] 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 comprises an oxide composed of Li, Ni, Mn, and O. 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 F, Cl, and Br. The aforementioned negative electrode contains Bi as the main component of the negative electrode active material. [Effects of the Invention]

[0006] This disclosure provides a novel, operable battery using a positive electrode active material comprising an oxide composed of Li, Ni, Mn, and O. [Brief explanation of the drawing]

[0007] [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. [Figure 4] Figure 4 is a graph showing the charge and discharge curves of the battery in Example 2. [Modes for carrying out the invention]

[0008] (Summary of one aspect of this disclosure) The battery relating to the first aspect of this disclosure 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 comprises an oxide composed of Li, Ni, Mn, and O. 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 F, Cl, and Br. The aforementioned negative electrode contains Bi as the main component of the negative electrode active material.

[0009] According to the first embodiment, a novel operable battery is provided that uses a positive electrode active material comprising an oxide composed of Li, Ni, Mn, and O. In the negative electrode of the battery according to the first embodiment, Bi is included as the main component of the negative electrode active material. Bi does not have the property of having a large difference in potential between multiple compounds formed with lithium, such as tin. Therefore, electrodes containing Bi as an active material have excellent discharge flatness. In the positive electrode of the battery according to the first embodiment, the positive electrode active material comprises an oxide composed of Li, Ni, Mn, and O, and has a relatively high potential.

[0010] In a second aspect of this disclosure, for example, in the battery according to the first aspect, the first solid electrolyte material may cover at least a portion of the surface of the positive electrode active material.

[0011] According to the second embodiment, since at least a portion of the surface of the positive electrode active material is covered with the first solid electrolyte material, the formation of an oxidative decomposition layer by the halide solid electrolyte is suppressed, and the increase in internal resistance can be suppressed. As a result, the battery according to the second embodiment has an improved charge and discharge capacity.

[0012] In a third aspect of this disclosure, for example, in a battery according to the first or second aspect, the positive electrode material may further include a second electrolyte material having a different composition from the first solid electrolyte material.

[0013] The battery according to the third embodiment has improved charge and discharge characteristics.

[0014] In a fourth aspect of this disclosure, for example, in a battery according to any one of the first to third aspects, the positive electrode active material may include a material represented by the following composition formula (1). LiNi x Mn 2-x O4···Formula (1) Here, x satisfies 0 < x < 2.

[0015] The battery according to the fourth aspect can operate at a high potential.

[0016] In the fifth aspect of the present disclosure, for example, in the battery according to the fourth aspect, the composition formula (1) may satisfy 0 < x < 1.

[0017] The battery according to the fifth aspect can operate at a higher potential.

[0018] In the sixth aspect of the present disclosure, for example, in the battery according to the fifth aspect, the composition formula (1) may satisfy x = 0.5.

[0019] The battery according to the sixth aspect can operate at a higher potential.

[0020] In the seventh aspect of the present disclosure, for example, in the battery according to any one of the first to sixth aspects, the oxide may have a spinel structure.

[0021] The battery according to the seventh aspect can operate at a high potential.

[0022] In the eighth aspect of the present disclosure, for example, in the battery according to any one of the first to seventh aspects, the first solid electrolyte material may contain Li, Ti, Al, and F.

[0023] The battery according to the eighth aspect has a high oxidation resistance for the first solid electrolyte material. Therefore, it is possible to suppress a decrease in charge-discharge capacity due to oxidative decomposition of the first solid electrolyte material.

[0024] In the ninth aspect of the present disclosure, for example, in the battery according to any one of the first to eighth aspects, the negative electrode may contain Bi single substance as the negative electrode active material.

[0025] The battery according to the 9th aspect has improved charge-discharge characteristics.

[0026] In the 10th aspect of the present disclosure, for example, in the battery according to any one of the 1st to 10th aspects, the negative electrode may be a plating layer.

[0027] The battery according to the 10th aspect has improved capacity.

[0028] In the 11th aspect of the present disclosure, for example, in the battery according to the 3rd aspect, the second electrolyte material may contain a material represented by the following compositional formula (3). Li α3 M β3 X γ3 O δ3 ···Formula (3) Here, α3, β3, and γ3 are values greater than 0, δ3 is a value of 0 or more, M is at least one selected from the group consisting of metal elements and metalloid elements other than Li, and X is at least one element selected from the group consisting of F, Cl, Br, and I.

[0029] The battery according to the 11th aspect has improved charge-discharge characteristics.

[0030] In the 12th aspect of the present disclosure, for example, in the battery according to the 11th aspect, the compositional formula (3) is 1 ≦ α3 ≦ 4, 0 < β3 ≦ 2, 3 ≦ γ3 < 7, and 0 ≦ δ3 ≦ 2, may satisfy.

[0031] In the battery according to the 12th aspect, the ionic conductivity of the second electrolyte material can be increased. Thereby, the resistance derived from the movement of Li ions can be further reduced.

[0032] In the 13th aspect of the present disclosure, for example, in the battery according to the 12th aspect, the compositional formula (3) is 2.5 ≦ α3 ≦ 3, 1 ≦ β3 ≦ 1.1, γ3=6, and δ3=0, It may satisfy the requirement.

[0033] In the battery according to the 13th embodiment, the ionic conductivity of the second electrolyte material can be increased. This makes it possible to further reduce the resistance caused by the movement of Li ions.

[0034] In a fourteenth aspect of this disclosure, for example, in a battery according to any one of the first to thirteenth aspects, the electrolyte layer may include a sulfide solid electrolyte.

[0035] The battery according to the 14th embodiment has improved charge and discharge characteristics.

[0036] In a 15th aspect of this disclosure, for example, in the battery according to the 14th aspect, the sulfide solid electrolyte may be Li6PS5Cl.

[0037] The battery according to the 15th embodiment has improved charge and discharge characteristics.

[0038] In a sixteenth aspect of this disclosure, for example, in a battery according to any one of the first to fifteenth aspects, the electrolyte layer may include a material comprising 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 F, Cl, and Br.

[0039] The battery according to the 16th embodiment has improved charge and discharge characteristics.

[0040] In a 17th aspect of this disclosure, for example, in the battery according to the 16th aspect, the electrolyte layer may include Li3YBr2Cl4.

[0041] The battery according to the 17th embodiment has improved charge and discharge characteristics.

[0042] In the eighteenth aspect of this disclosure, for example, in a battery according to any one of the first to seventeenth aspects, the electrolyte layer includes 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.

[0043] The battery according to the 18th embodiment can suppress the increase in internal resistance during charging.

[0044] In a 19th aspect of this disclosure, for example, in a battery according to the 18th aspect, the positive electrode material further comprises a second electrolyte material having a different composition from the first solid electrolyte material, and the first electrolyte layer may comprise a material having the same composition as the second electrolyte material.

[0045] The battery according to the 19th embodiment can further suppress the increase in internal resistance during charging.

[0046] 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.

[0047] (Embodiment 1) The battery of this disclosure comprises a positive electrode, a negative electrode, and an electrolyte layer located between the positive electrode and the negative electrode. 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 an oxide consisting of Li, Ni, Mn, and O. The first solid electrolyte material includes 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 F, Cl, and Br. The negative electrode includes Bi as the main component of the negative electrode active material.

[0048] The statement "The negative electrode contains Bi as the main component of the negative electrode active material" means that "in the negative electrode, Bi is the component that is present in the largest molar ratio as the negative electrode active material."

[0049] The first solid electrolyte material may cover at least a portion of the surface of the positive electrode active material.

[0050] The positive electrode material may further include a second electrolyte material having a different composition from the first solid electrolyte material.

[0051] Figure 1 is a cross-sectional view showing the schematic configuration of the battery 2000 in Embodiment 1.

[0052] 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 111. The positive electrode active material 110 includes an oxide composed of Li, Ni, Mn, and O. The first solid electrolyte material 111 includes 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 F, Cl, and Br. The negative electrode 203 contains Bi as the main component of the negative electrode active material. Figure 1 shows an example of the configuration of the battery 2000 in which the first solid electrolyte material 111 covers at least a portion of the surface of the positive electrode active material 110, and the positive electrode material 1000 further includes a second electrolyte material 100.

[0053] The following describes the various components of the battery 2000 in this embodiment.

[0054] [Positive electrode 201] As described above, 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 111. The positive electrode active material 110 includes an oxide consisting of Li, Ni, Mn, and O. The first solid electrolyte material 111 includes 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 F, Cl, and Br.

[0055] "Metallic elements" are B, Si, Ge, As, Sb, and Te.

[0056] The "metal element" refers to all elements contained in Groups 1 to 12 of the periodic table excluding hydrogen, and elements contained in Groups 13 to 16 excluding B, Si, Ge, As, Sb, Te, C, N, P, O, S, and Se. That is, it is a group of elements that can become cations when forming halogen compounds and inorganic compounds.

[0057] According to the above configuration, the positive electrode material 1000 has high oxidation resistance. Therefore, the positive electrode material 1000 can suppress the increase in the internal resistance of the battery during charging. Also, the first solid electrolyte material 111 has high ionic conductivity. Therefore, in the positive electrode material 1000, a low interfacial resistance between the first solid electrolyte material 111 and the positive electrode active material 110 can be realized.

[0058] The first solid electrolyte material 111 may cover at least a part of the surface of the positive electrode active material 110.

[0059] The positive electrode active material 110 may contain a material represented by the following compositional formula (1). LiNi x Mn 2-x O4 ··· Formula (1) Here, 0 < x < 2 is satisfied.

[0060] In the compositional formula (1), 0 < x < 1 may be satisfied.

[0061] In the compositional formula (1), x = 0.5 may be satisfied. That is, the positive electrode active material 110 may contain LiNi 0.5 Mn 1.5 O4.

[0062] The oxides represented by these chemical formulas are materials obtained by substituting some of the manganese in LiMn2O4, which has a spinel structure, with nickel, and are suitable for improving the operating voltage of batteries. Oxides composed of Li, Ni, Mn, and O can also have a spinel structure. "Oxides composed of Li, Ni, Mn, and O" means that, apart from unavoidable impurities, no elements other than Li, Ni, Mn, and O have been intentionally added.

[0063] With the above configuration, the decrease in the battery's charge and discharge capacity can be suppressed. Furthermore, the material represented by composition formula (1) is inexpensive because it does not contain Co. With the above configuration, the cost of the Battery 2000 can be reduced.

[0064] An oxide composed of Li, Ni, Mn, and O may have a spinel structure.

[0065] The positive electrode active material 110 is LiNi 0.5 Mn 1.5 It may consist only of O4.

[0066] With the above configuration, the decrease in the battery's charge and discharge capacity can be suppressed.

[0067] The first solid electrolyte material 111 may contain Li, Ti, Al, and F.

[0068] The first solid electrolyte material 111 may consist substantially of Li, Ti, Al, and F. "The first solid electrolyte material 111 consists substantially of Li, Ti, Al, and F" means that the molar ratio (i.e., mole fraction) of the total amount of substance of Li, Ti, Al, and F to the total amount of substance of all elements constituting the first solid electrolyte material 111 is 90% or more. For example, this molar ratio may be 95% or more.

[0069] The first solid electrolyte material 111 may consist only of Li, Ti, Al, and F.

[0070] The first solid electrolyte material 111 may contain a material represented by the following compositional formula (2A). Here, α1, β1, γ1, and δ1 are values ​​greater than 0. Li α1 Ti β1 Al γ1 F δ1 ...Formula (2A)

[0071] In empirical formula (2A), δ1 may be greater than α1. δ1 may also be greater than each of α1, β1, and γ1.

[0072] In the composition formula (2A), the following conditions may be satisfied: 1.7 ≤ α1 ≤ 3.7, 0 < β1 < 1.5, 0 < γ1 < 1.5, and 5 ≤ δ1 ≤ 7.

[0073] In empirical formula (2A), the following conditions may be satisfied: 2.5 ≤ α1 ≤ 3, 0.1 ≤ β1 ≤ 0.6, 0.4 ≤ γ1 ≤ 0.9, and δ1 = 6.

[0074] The first solid electrolyte material 111 may contain as its main component the material represented by compositional formula (2A). Here, "the first solid electrolyte material 111 contains as its main component the material represented by compositional formula (2A)" means that "the material that is present in the largest mass of the first solid electrolyte material 111 is the material represented by compositional formula (2A)."

[0075] The first solid electrolyte material 111 may include a material represented by the following compositional formula (2B). Li α2 Ti β2 Al γ2 F6...Formula (2B) Here, α2, β2, and γ2 are values ​​greater than 0.

[0076] In empirical formula (2B), the equation α² + 4β² + 3γ² = 6 may also be satisfied.

[0077] In compositional formula (2B), α2, β2, and γ2 may satisfy the following conditions: α2=2.7, β2=0.3, and γ2=0.7. That is, the first solid electrolyte material 111 is Li 2.7 Ti 0.3 Al 0.7 It may include F6.

[0078] The first solid electrolyte material 111 may contain as its main component the material represented by compositional formula (2B). Here, "the first solid electrolyte material 111 contains as its main component the material represented by compositional formula (2B)" means that "the material that is present in the largest mass of the first solid electrolyte material 111 is the material represented by compositional formula (2B)."

[0079] The first solid electrolyte material 111 is Li 2.7 Ti 0.3 Al 0.7 It may contain F6 as its main component.

[0080] The first solid electrolyte material 111 is Li 2.7 Ti 0.3 Al 0.7 It may consist only of F6.

[0081] With the above configuration, the first solid electrolyte material 111 exhibits higher ionic conductivity. Therefore, in the positive electrode material 1000, a low interfacial resistance can be achieved between the first solid electrolyte material 111 and the positive electrode active material 110, thereby improving the charge and discharge efficiency of the battery 2000.

[0082] To further increase the ionic conductivity of the first solid electrolyte material 111, the first solid electrolyte material 111 may contain elements other than F as anions. Examples of elements that may be included as anions are Cl, Br, I, O, S, or Se. Furthermore, the first solid electrolyte material 111 may not contain sulfur.

[0083] The positive electrode material 1000 may further include a second electrolyte material 100 having a different composition from the first solid electrolyte material 111.

[0084] The second electrolyte material 100 may also be represented by the following compositional formula (3). Li α3 M β3 X γ3 O δ3 ...Equation (3) Here, α3, β3, and γ3 are values ​​greater than 0, δ3 is a value greater than or equal to 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 F, Cl, Br, and I.

[0085] With the above configuration, the ionic conductivity of the second 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.

[0086] In compositional formula (3), M may include at least one element selected from the group consisting of Y and Ta. That is, the second electrolyte material 100 may include at least one element selected from the group consisting of Y and Ta as a metallic element.

[0087] With the above configuration, the ionic conductivity of the second 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.

[0088] In empirical formula (3), the following conditions may be satisfied: 1 ≤ α3 ≤ 4, 0 < β3 ≤ 2, 3 ≤ γ3 < 7, and 0 ≤ δ3 ≤ 2.

[0089] With the above configuration, the ionic conductivity of the second 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.

[0090] In empirical formula (3), the following conditions may be satisfied: 2.5 ≤ α3 ≤ 3, 1 ≤ β3 ≤ 1.1, γ3 = 6, and δ3 = 0.

[0091] The second electrolyte material 100 containing Y may be, for example, a compound represented by the composition formula of Li a Me b Y c X6, where 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 other than Li and Y. Also, m' is the valence of Me.

[0092] 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.

[0093] According to the above configuration, the ionic conductivity of the second electrolyte material 100 can be further increased. Thereby, the resistance resulting from the movement of Li ions in the positive electrode material 1000 can be further reduced.

[0094] The second electrolyte material 100 may be a material represented by the following composition formula (A1). Li 6-3d Y d X6 ··· formula (A1) Here, in the composition formula (A1), X is a halogen element and contains Cl. Also, 0 < d < 2 is satisfied.

[0095] According to the above configuration, the ionic conductivity of the second electrolyte material 100 can be further increased. Thereby, the resistance resulting from the movement of Li ions in the positive electrode material 1000 can be further reduced.

[0096] The second electrolyte material 100 may be a material represented by the following composition formula (A2). Li3YX6 ··· formula (A2) Here, in the composition formula (A2), X is a halogen element and contains Cl.

[0097] According to the above configuration, the ionic conductivity of the second electrolyte material 100 can be further increased. Thereby, the resistance resulting from the movement of Li ions in the positive electrode material 1000 can be further reduced.

[0098] The second 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 the compositional formula (A3), 0 < δ ≦ 0.15 is satisfied.

[0099] According to the above configuration, the ionic conductivity of the second electrolyte material 100 can be further increased. Thereby, the resistance resulting from the movement of Li ions in the positive electrode material 1000 can be further reduced.

[0100] The second 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.

[0101] According to the above configuration, the ionic conductivity of the second electrolyte material 100 can be further increased. Thereby, the resistance resulting from the movement of Li ions in the positive electrode material 1000 can be further reduced.

[0102] The second 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.

[0103] According to the above configuration, the ionic conductivity of the second electrolyte material 100 can be further increased. Thereby, the resistance resulting from the movement of Li ions in the positive electrode material 1000 can be further reduced.

[0104] The second 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.

[0105] The second electrolyte material 100 may be a material represented by the following compositional formula (A7). Li 3-3δ-2a7 Y 1+δ-a7 Me a7 Cl 6-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.

[0106] As the second electrolyte material 100, for example, Li3YX6, Li2MgX4, Li2FeX4, Li(Al,Ga,In)X4, Li3(Al,Ga,In)X6, etc. can be used. Here, X includes Cl. In this 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 in parentheses. That is, "(Al,Ga,In)" is synonymous with "at least one element selected from the group consisting of Al, Ga, and In". The same applies to other elements. The second electrolyte material 100 does not have to contain sulfur.

[0107] The second electrolyte material 100 may contain a sulfide solid electrolyte. Examples of sulfide solid electrolytes include 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. In addition, LiX, Li2O, MO q Li p MO q The 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.

[0108] The second 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.

[0109] The second electrolyte material 100 may be a sulfide solid electrolyte.

[0110] The second electrolyte material 100 may further contain an electrolyte solution.

[0111] The electrolyte contains water or a non-aqueous solvent and a lithium salt dissolved in the solvent.

[0112] Examples of solvents include water, cyclic carbonate solvents, linear carbonate solvents, cyclic ether solvents, linear ether solvents, cyclic ester solvents, linear ester solvents, or fluorine solvents.

[0113] Examples of cyclic carbonate ester solvents include ethylene carbonate, propylene carbonate, or butylene carbonate. Examples of linear carbonate ester solvents include dimethyl carbonate, ethyl methyl carbonate, or diethyl carbonate. Examples of cyclic ether solvents include tetrahydrofuran, 1,4-dioxane, or 1,3-dioxolane. Examples of linear ether solvents include 1,2-dimethoxyethane or 1,2-diethoxyethane. Examples of cyclic ester solvents include γ-butyrolactone. Examples of linear ester solvents include methyl acetate. Examples of fluorine solvents include fluoroethylene carbonate, methyl fluoropropionate, fluorobenzene, fluoroethyl methyl carbonate, or fluorodimethylene carbonate.

[0114] One solvent selected from these may be used alone, or a combination of two or more solvents selected from these may be used.

[0115] The electrolyte may contain at least one fluorine solvent selected from the group consisting of fluoroethylene carbonate, methyl fluoropropionate, fluorobenzene, fluoroethyl methyl carbonate, and fluorodimethylene carbonate.

[0116] Lithium salts that can be used include LiPF6, LiBF4, LiSbF6, LiAsF6, LiSO3CF3, LiN(SO2CF3)2, LiN(SO2C2F5)2, LiN(SO2CF3)(SO2C4F9), LiC(SO2CF3)3, etc. One lithium salt selected from these can be used alone, or a mixture of two or more lithium salts selected from these can be used. The concentration of the lithium salt is, for example, in the range of 0.1 mol / liter to 15 mol / liter.

[0117] The positive electrode material 1000 may further contain other positive electrode active materials besides the positive electrode active material 110, which is an oxide composed of Li, Ni, Mn, and O.

[0118] 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.

[0119] A first solid electrolyte material 111 may be provided between the positive electrode active material 110 and the second electrolyte material 100.

[0120] With the above configuration, the first solid electrolyte material 111, which has high oxidation resistance, is interposed between the positive electrode active material 110 and the second electrolyte material 100, thereby suppressing the oxidative decomposition of the second electrolyte material 100. As a result, the decrease in capacity during charging of the battery 2000 can be suppressed.

[0121] When the first solid electrolyte material 111 covers at least a portion of the surface of the positive electrode active material 110, the thickness of the first solid electrolyte material 111 covering at least a portion of the surface of the positive electrode active material 110 may be 1 nm or more and 500 nm or less.

[0122] When the thickness of the first solid electrolyte material 111 is 1 nm or more, direct contact between the positive electrode active material 110 and the second electrolyte material 100 is suppressed, and oxidative decomposition of the second electrolyte material 100 can be suppressed. Therefore, the charge and discharge efficiency of the battery using the positive electrode material 1000 can be improved. When the thickness of the first solid electrolyte material 111 is 500 nm or less, the thickness of the first solid electrolyte material 111 does not become too thick. Therefore, the internal resistance of the battery using the positive electrode material 1000 can be sufficiently reduced, and the energy density of the battery can be increased.

[0123] The method for measuring the thickness of the first solid electrolyte material 111 is not particularly limited, but for example, it can be determined by directly observing the thickness of the first solid electrolyte material 111 using a transmission electron microscope.

[0124] The mass ratio of the first solid electrolyte material 111 to the positive electrode active material 110 may be 0.01% or more and 30% or less.

[0125] When the mass ratio of the first solid electrolyte material 111 to the positive electrode active material 110 is 0.01% or more, direct contact between the positive electrode active material 110 and the second electrolyte material 100 is suppressed, and oxidative decomposition of the second electrolyte material 100 can be suppressed. Therefore, the charge and discharge efficiency of the battery can be improved. When the mass ratio of the first solid electrolyte material 111 to the positive electrode active material 110 is 30% or less, the thickness of the first solid electrolyte material 111 does not become too thick. Therefore, the internal resistance of the battery can be sufficiently reduced, and the energy density of the battery can be increased.

[0126] The first solid electrolyte material 111 may uniformly coat the surface of the positive electrode active material 110. This suppresses direct contact between the positive electrode active material 110 and the second electrolyte material 100, thereby suppressing side reactions of the second electrolyte material 100. As a result, the charge and discharge characteristics of the battery can be further improved, and capacity degradation can be suppressed.

[0127] The first solid electrolyte material 111 may cover a portion of the surface of the positive electrode active material 110. Direct contact between multiple positive electrode active materials 110 through the portion without the first solid electrolyte material 111 improves the electronic conductivity between them. This enables the battery to operate at high power.

[0128] The first solid electrolyte material 111 may cover 30% or more, 60% or more, or 90% or more of the surface of the positive electrode active material 110. The first solid electrolyte material 111 may substantially cover the entire surface of the positive electrode active material 110.

[0129] The positive electrode active material 110 may be covered with at least a portion of its surface by a coating material different from the first solid electrolyte material 111.

[0130] Coating materials include sulfide solid electrolytes, oxide solid electrolytes, and fluoride solid electrolytes. The sulfide solid electrolyte used in the coating material may be the same material as exemplified in the second 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 12Examples 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. Examples of fluoride solid electrolytes used in coating materials include solid electrolytes containing Li, Ti, M1, and F, where M1 is at least one element selected from the group consisting of Ca, Mg, Al, Y, and Zr.

[0131] With the above configuration, the oxidation resistance of the positive electrode material 1000 can be further improved. This makes it possible to suppress the decrease in capacity of the battery 2000 during charging.

[0132] The positive electrode active material 110 and the first solid electrolyte material 111 do not need to be in direct contact with each other, as they are separated by a coating material.

[0133] With the above configuration, the oxidation resistance of the positive electrode material 1000 can be further improved. This makes it possible to suppress the decrease in battery capacity during charging.

[0134] The shape of the second electrolyte material 100 is not particularly limited. If the second electrolyte material 100 is a powder material, its shape may be, for example, needle-shaped, spherical, ellipsoidal, etc. For example, the shape of the second electrolyte material 100 may be particulate.

[0135] For example, if the shape of the second electrolyte material 100 is particulate (e.g., spherical), the median diameter of the second electrolyte material 100 may be 100 μm or less. When the median diameter of the second electrolyte material 100 is 100 μm or less, the positive electrode active material 110 and the second 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 using the positive electrode material 1000 are improved.

[0136] The median diameter of the second electrolyte material 100 may be 10 μm or less. With the above configuration, the positive electrode active material 110 and the second electrolyte material 100 can form a good dispersion state in the positive electrode material 1000.

[0137] In Embodiment 1, the median diameter of the second electrolyte material 100 may be smaller than the median diameter of the positive electrode active material 110. With the above configuration, the second electrolyte material 100 and the positive electrode active material 110 can form a better dispersion state in the positive electrode.

[0138] The median diameter of the positive electrode active material 110 may be 0.1 μm or more and 100 μm or less.

[0139] 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 second 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 using the positive electrode material 1000 can operate at high power.

[0140] The median diameter of the positive electrode active material 110 may be larger than the median diameter of the second electrolyte material 100. This allows the positive electrode active material 110 and the second electrolyte material 100 to form a good dispersion state.

[0141] 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.

[0142] In the positive electrode material 1000, the second electrolyte material 100 and the first solid electrolyte material 111 may be in contact with each other, as shown in Figure 1. In this case, the first solid electrolyte material 111 and the positive electrode active material 110 are in contact with each other.

[0143] The positive electrode material 1000 may include a plurality of second electrolyte materials 100 and a plurality of positive electrode active materials 110.

[0144] The content of the second 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.

[0145] The volume ratio "v1:100-v1" of the positive electrode active material 110 and the first solid electrolyte material 111 to the second electrolyte material 100 contained in the positive electrode 201 may satisfy 30 ≤ v1 ≤ 98. Here, v1 represents the volume ratio of the positive electrode active material 110 and the first solid electrolyte material 111 when the total volume of the positive electrode active material 110, the first solid electrolyte material 111, and the second 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.

[0146] 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.

[0147] <Method for manufacturing positive electrode material 1000> The positive electrode material 1000 included in the battery 2000 in Embodiment 1 can be manufactured, for example, by the following method.

[0148] First, the first solid electrolyte material 111 is prepared. A binary halide raw material powder is prepared in a ratio that matches the desired composition. For example, Li 2.7 Ti 0.3 Al 0.7 When preparing F6, LiF, TiF4, and AlF3 should be prepared in a molar ratio of approximately LiF:TiF4:AlF3 = 2.7:0.3:0.7. The mixing ratio may be adjusted beforehand to compensate for any changes in composition during the synthesis process.

[0149] After thoroughly mixing the raw material powders, the powders are mixed and pulverized using a mechanochemical milling method and then reacted. The mixture may then be fired in a vacuum or inert atmosphere. Alternatively, the raw material powders may be thoroughly mixed before firing in a vacuum or inert atmosphere. The firing conditions are preferably, for example, within a temperature range of 100°C to 300°C for at least one hour. Furthermore, to suppress changes in composition during the firing process, it is preferable to seal the raw material powders in a sealed container such as a quartz tube before firing.

[0150] This yields a first solid electrolyte material 111 containing the composition described above.

[0151] Next, a positive electrode active material 110 and a first solid electrolyte material 111 are prepared in a predetermined mass ratio. For example, LiNi 0.5 Mn 1.5 O4, Li as the first solid electrolyte material 111 2.7 Ti 0.3 Al 0.7 Prepare F6. These two materials are placed in the same reaction vessel, and a shear force is applied to the two materials using a rotating blade, or the two materials are made to collide using a jet stream, thereby generating the positive electrode active material LiNi 0.5 Mn 1.5 Li, which is the first solid electrolyte material 111, is present on at least a portion of the surface of the O4. 2.7 Ti 0.3 Al 0.7 F6 can be coated. For example, devices such as the dry particle compounding device Novilta (manufactured by Hosokawa Micron), the high-speed airflow impact device (manufactured by Nara Machine Works), and the jet mill can be used. In this way, LiNi, which is the positive electrode active material 110, can be coated. 0.5 Mn 1.5 At least a portion of the surface of O4 is Li, which is the first solid electrolyte material 111. 2.7 Ti 0.3 Al 0.7 A positive electrode active material coated with F6 can be manufactured.

[0152] Next, the second electrolyte material 100 is prepared. For example, when synthesizing the second electrolyte material 100 consisting of Li, Y, Cl, and Br, LiCl raw material powder, LiBr raw material powder, YBr3 raw material powder, and YCl3 raw material powder are mixed. The raw material powders may be mixed in a pre-adjusted molar ratio to counteract any compositional changes that may occur during the synthesis process. In this way, the second electrolyte material 100 is obtained.

[0153] A positive electrode material 1000 can be manufactured by mixing a positive electrode active material 110, whose surface is coated with a first solid electrolyte material 111, with a second electrolyte material 100.

[0154] [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.

[0155] 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.

[0156] Unlike tin, for example, Bi does not exhibit the property of having significantly different potentials among the various compounds it forms with lithium. For this reason, negative electrode 203, which contains Bi as the negative electrode active material, exhibits excellent discharge flatness.

[0157] The negative electrode 203 may include at least one selected from the group consisting of LiBi and Li3Bi.

[0158] The negative electrode 203 may contain elemental Bi as the negative electrode active material.

[0159] The negative electrode 203 may contain only elemental Bi as the negative electrode active material.

[0160] The negative electrode 203 may contain materials other than Bi as the negative electrode active material.

[0161] 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.

[0162] The negative electrode 203 does not necessarily contain an electrolyte. For example, the negative electrode 203 may consist of at least one layer selected from the group consisting of pure Bi and a lithium bismuth alloy produced during charging.

[0163] The negative electrode 203 may be in the form of a thin film.

[0164] The negative electrode 203 may be a plated layer.

[0165] The negative electrode 203 may be a plated layer formed by the deposition of Bi by plating.

[0166] 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.

[0167] 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.

[0168] 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.

[0169] The negative electrode 203 may be positioned in direct contact with the surface of the negative electrode current collector.

[0170] 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.

[0171] 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.

[0172] 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.

[0173] The negative electrode current collector may contain copper (Cu).

[0174] 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.

[0175] [Electrolyte layer 202] The electrolyte layer 202 is placed between the positive electrode 201 and the negative electrode 203.

[0176] 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.

[0177] As the solid electrolyte material contained in the electrolyte layer 202, the same material as the first solid electrolyte material 111 or the second electrolyte material 100 may be used. That is, the electrolyte layer 202 may contain the same material as the first solid electrolyte material 111 or the second electrolyte material 100. The electrolyte layer 202 may contain a material containing Li, at least one selected from the group consisting of metal elements and metalloid elements other than Li, and at least one selected from the group consisting of F, Cl, and Br. The electrolyte layer 202 may contain a material represented by the above composition formula (3).

[0178] According to the above configuration, the output density and charge-discharge characteristics of the battery 2000 can be further improved.

[0179] As the solid electrolyte material contained in the electrolyte layer 202, the same material as the first solid electrolyte material 111 may be used. That is, the electrolyte layer 202 may contain the same material as the first solid electrolyte material 111.

[0180] According to the above configuration, an increase in the internal resistance of the battery 2000 due to oxidation of the electrolyte layer 202 can be suppressed, and the output density and charge-discharge characteristics of the battery 2000 can be further improved.

[0181] As the solid electrolyte material contained in the electrolyte layer 202, a halide solid electrolyte, a sulfide solid electrolyte, an oxide solid electrolyte, a polymer solid electrolyte, or a complex hydride solid electrolyte may be used.

[0182] Examples of the oxide solid electrolyte contained in the electrolyte layer 202 include NASICON-type solid electrolytes represented by LiTi2(PO4)3 and its element substitution products, perovskite-type solid electrolytes of the (LaLi)TiO3 system, Li 14 ZnGe4O 16 , Li4SiO4, LiGeO4, and LISICON-type solid electrolytes represented by their element substitution products, Li7La3Zr2O 12Garnet-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.

[0183] As the polymer solid electrolyte contained in the electrolyte layer 202, for example, a compound of a polymer compound and a lithium salt may 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(SO2CF3)2, LiN(SO2C2F5)2, LiN(SO2CF3)(SO2C4F9), and LiC(SO2CF3)3. One lithium salt selected from the exemplified lithium salts may be used alone. Alternatively, a mixture of two or more lithium salts selected from the exemplified lithium salts may be used.

[0184] Examples of complex hydride solid electrolytes that can be included in the electrolyte layer 202 include LiBH4-LiI and LiBH4-P2S5.

[0185] 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.

[0186] With the above configuration, the charge and discharge characteristics of the battery 2000 can be further improved.

[0187] 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).

[0188] With the above configuration, the charge and discharge characteristics of the battery 2000 can be further improved.

[0189] 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.

[0190] 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.

[0191] With the above configuration, the charge and discharge characteristics of the battery 2000 can be further improved.

[0192] As described above, the electrolyte layer 202 may be composed solely of solid electrolyte material.

[0193] 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.

[0194] The electrolyte layer 202 may contain Li6PS5Cl.

[0195] The electrolyte layer 202 may contain Li3YBr2Cl4.

[0196] 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.

[0197] 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.

[0198] 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.

[0199] 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.

[0200] Examples of the shapes of the battery 2000 in Embodiment 1 include coin-shaped, cylindrical, rectangular, sheet-shaped, button-shaped, flat, and stacked types.

[0201] 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.

[0202] (Embodiment 2) Embodiment 2 will be described below. Descriptions that overlap with Embodiment 1 will be omitted as appropriate.

[0203] Figure 2 is a cross-sectional view showing the schematic configuration of the battery 3000 in Embodiment 2.

[0204] 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.

[0205] With the above configuration, the increase in the internal resistance of the battery 3000 during charging can be suppressed.

[0206] The first electrolyte layer 301 may contain a material having the same composition as the second electrolyte material 100.

[0207] The first electrolyte layer 301 may contain a material having the same composition as the first solid electrolyte material 111.

[0208] By including a first solid electrolyte material 111 with excellent oxidation resistance in the first electrolyte layer 301, oxidative decomposition of the first electrolyte layer 301 can be suppressed, thereby suppressing the increase in the internal resistance of the battery 3000 during charging.

[0209] The second electrolyte layer 302 may also contain a material having a different composition from the first solid electrolyte material 111.

[0210] For example, the reduction potential of the solid electrolyte material contained in the second electrolyte layer 302 may be lower than that 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 becomes less susceptible to reduction. This can improve the charge and discharge efficiency of the battery 3000.

[0211] For example, the second electrolyte layer 302 may include a sulfide solid electrolyte. Here, the reduction potential of the sulfide solid electrolyte 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. According to the above configuration, the solid electrolyte material contained in the first electrolyte layer 301 is less likely to be reduced. Thereby, the charge and discharge efficiency of the battery 3000 can be improved.

[0212] The thicknesses 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 thicknesses of the first electrolyte layer 301 and the second electrolyte layer 302 are 1 μm or more, it becomes difficult for the positive electrode 201 and the negative electrode 203 to short-circuit. When the thicknesses of the first electrolyte layer 301 and the second electrolyte layer 302 are 300 μm or less, the battery 3000 can operate at high power.

Example

[0213] Hereinafter, the present disclosure will be described in more detail while referring to examples.

[0214] <Example 1> [Preparation of the first solid electrolyte material] In an argon atmosphere, LiF, TiF4, and AlF3 as raw material powders were weighed so as to have a molar ratio of LiF:TiF4:AlF3 = 2.7:0.3:0.7. Then, using a planetary ball mill (manufactured by Fritsch, P-7 type), milling was performed at 500 rpm for 12 hours to obtain a powder of Li 2.7 Ti 0.3 Al 0.7 F6.

[0215] [Preparation of a positive electrode active material coated with the first solid electrolyte material] In an argon atmosphere, LiNi 0.5 Mn 1.5 O4 as a positive electrode active material and the first solid electrolyte material of Example 1 were mixed with LiNi 0.5 Mn 1.5The materials were weighed to achieve a mass ratio of O4:first solid electrolyte material = 100:3. These materials were placed in a dry particle compounding device, Novilta (manufactured by Hosokawa Micron), and compounding treatment was carried out at 6000 rpm for 30 minutes to obtain a positive electrode active material whose surface was coated with the first solid electrolyte material of Example 1.

[0216] [Preparation of the second electrolyte material] In a dry atmosphere with a dew point of -30°C or lower (hereinafter referred to as the "dry atmosphere"), Li2O2 and TaCl5 were prepared as raw material powders in a molar ratio of Li2O2:TaCl5 = 1.2:2. These raw material powders were ground and mixed in a mortar to obtain a mixed powder. The obtained mixed powder was milled using a planetary ball mill at 600 rpm for 24 hours. Then, the mixed powder was calcined at 200°C for 6 hours. In this way, a powder of the Li-Ta-O-Cl system second electrolyte material was obtained.

[0217] [Fabrication of cathode materials] The cathode active material of Example 1 was prepared by weighing the surface coated with the first solid electrolyte material of Example 1, the second electrolyte material, and vapor-phase carbon fiber (VGCF (manufactured by Showa Denko K.K.)) as a conductive additive in a mass ratio of coated cathode active material:second electrolyte material:VGCF = 72.8:26.2:1.0 and mixing them in a mortar. VGCF is a registered trademark of Showa Denko K.K.

[0218] [Fabrication of solid electrolyte materials for the electrolyte layer] 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.

[0219] [Fabrication of the negative electrode] As a pretreatment, copper foil (10cm x 10cm, thickness: 10μm) was pre-degreased with an organic solvent, then one side was masked and degreased by immersion in an acidic solvent to activate the copper foil surface. In 1.0 mol / L of methanesulfonic acid, bismuth methanesulfonate was added as a soluble bismuth salt. 3+ A plating bath was prepared by adding ions to a concentration of 0.18 mol / L. The activated copper foil was connected to a power supply so that current could be applied, and then immersed in the plating bath. Subsequently, the current density was set to 2 A / dm². 2 By controlling the process, Bi was electroplated onto the unmasked copper foil surface to a thickness of approximately 3 μm. After electroplating, the copper foil was recovered from the acidic bath, the masking was removed, and it was washed with pure water and dried. Subsequently, the negative electrode, which is the plated layer deposited on the current collector, was obtained by punching it out to a size of φ0.92 cm.

[0220] [Battery construction] The battery for Example 1 was fabricated using the following procedure.

[0221] First, 480 mg of Li3YBr2Cl was placed inside an insulating outer cylinder and molded under pressure at 2 MPa. Next, 20 mg of the second electrolyte material used as the positive electrode material in Example 1 was placed inside and molded under pressure at 2 MPa. Furthermore, 8.2 mg of the positive electrode material was placed inside and molded under pressure at 2 MPa. This resulted in obtaining a laminate consisting of a positive electrode and a solid electrolyte layer.

[0222] 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.

[0223] Next, stainless steel current collectors were placed above and below the laminate, and current collection leads were attached to the current collectors.

[0224] 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.

[0225] Based on the above, the battery of Example 1 described above was fabricated.

[0226] <Example 2> The battery of Example 2 was fabricated in the same manner as in Example 1, except that Li6PS5Cl was used in the solid electrolyte layer instead of Li3YBr2Cl4.

[0227] [Charging test] A charging test was conducted using the batteries from Example 1 and Example 2 described above, under the following conditions.

[0228] The battery was placed in a constant temperature bath at 85°C.

[0229] The battery was charged with a constant current of 6.8 μA, which corresponds to a rate of 0.01 C (20-hour rate) relative to its theoretical capacity. The charging termination voltage was set to 4.5 V. Next, the discharge termination voltage was set to 2.5 V, and the battery was discharged with a constant current.

[0230] Figure 3 is a graph showing the charge-discharge curve of the battery in Example 1. Figure 4 is a graph showing the charge-discharge curve of the battery in Example 2. As shown in Figures 3 and 4, the batteries in Examples 1 and 2 were charged and discharged. [Industrial applicability]

[0231] 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 an oxide composed of Li, Ni, Mn, and O. The first solid electrolyte material comprises Li, Ti, Al, and F. The aforementioned negative electrode contains Bi as the main component of the negative electrode active material. battery.

2. The first solid electrolyte material covers at least a portion of the surface of the positive electrode active material. The battery according to claim 1.

3. The positive electrode material further comprises a second electrolyte material having a different composition from the first solid electrolyte material. The battery according to claim 1 or 2.

4. The positive electrode active material includes a material represented by the following compositional formula (1): The battery according to claim 1 or 2. LiNi x Mn 2-x O 4 ・・・Form (1) Here, x satisfies 0 < x < 2.

5. The above composition formula (1) satisfies 0 < x < 1, The battery according to claim 4.

6. The above compositional formula (1) satisfies x = 0.5, The battery according to claim 5.

7. The said oxide has a spinel structure, The battery according to claim 1 or 2.

8. The negative electrode contains Bi elemental as the negative electrode active material. The battery according to claim 1 or 2.

9. The aforementioned negative electrode is a plating layer. The battery according to claim 1 or 2.

10. The second electrolyte material includes a material represented by the following compositional formula (3): The battery according to claim 3. Li α3 M β3 X γ3 O δ3 ... Formula (3) Here, α3, β3, and γ3 are values ​​greater than 0, and δ3 is a value greater than or equal to 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 F, Cl, Br, and I.

11. The aforementioned composition formula (3) is, １≦α３≦４、 ０＜β３≦２、 3 ≤ γ3 < 7, and 0 ≤ δ³ ≤ 2 Satisfying The battery according to claim 10.

12. The aforementioned composition formula (3) is, ２．５≦α３≦３、 １≦β３≦１．１、 γ3 = 6, and δ³ = 0 Satisfying The battery according to claim 11.

13. The electrolyte layer contains a sulfide solid electrolyte. The battery according to claim 1 or 2.

14. The sulfide solid electrolyte is Li 6 PS 5 Cl, The battery according to claim 13.

15. The electrolyte layer comprises a material containing 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 F, Cl, and Br. The battery according to claim 1 or 2.

16. The electrolyte layer is Li 3 YBr 2 Cl 4 including, The battery according to claim 15.

17. 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 or 2.

18. The positive electrode material further comprises a second electrolyte material having a different composition from the first solid electrolyte material. The first electrolyte layer comprises a material having the same composition as the second electrolyte material. The battery according to claim 17.

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