Positive electrode active material, positive electrode material, positive electrode layer, solid-state battery, and method for manufacturing a solid-state battery

Abstract

To provide a cathode active material capable of obtaining a battery with high initial discharge capacity and high capacity retention after repeated charging and discharging, a cathode material, a solid-state battery, and a manufacturing method of solid-state battery.SOLUTION: The cathode active material includes a lithium composite oxide having at least one structure selected from the O2 type structure, the T#2 type structure and the O6 type structure; defining the sum of the contents of metals other than Li and Na as 1, the Li content is 0.90 to 1.04; in a one-dimensional luminance spectrum, when the ratio of the maximum luminance Imax to the minimum luminance Imin at the maximum value of three consecutive peaks is calculated for a total of 75, the ratio of the maximum value Imax to the minimum value Imin is 0.3 or less in 2 out of 75. There are provided a cathode material, a solid-state battery, and a manufacturing method of the solid-state battery.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a positive electrode active material, a positive electrode material, a positive electrode layer, a solid-state battery, and a method for manufacturing a solid-state battery.

Background Art

[0002] A positive electrode active material containing a lithium composite oxide having an O2-type structure is stable up to a high potential, and thus has a large charge-discharge capacity in charge-discharge in a high potential region. Patent Document 1 discloses "a positive electrode active material used in a non-aqueous electrolyte secondary battery, which has a layered structure and contains a lithium-containing transition metal oxide in which the main arrangement of transition metal, oxygen, and lithium is represented by an O2 structure. The lithium-containing transition metal oxide has Li, Mn, and element M in a lithium-containing transition metal layer in the layered structure, and has a general composition formula Li x [Li α (Mn a M b ) 1-α O2, where 0.5 < x < 1.1, 0.1 < α < 0.33, 0.67 < a < 0.97, 0.03 < b < 0.33, and M contains at least one element selected from the group consisting of Ni, Mg, Ti, Fe, Sn, Zr, Nb, Mo, W, and Bi. A positive electrode active material for a non-aqueous electrolyte secondary battery." Further, Patent Document 2 discloses "a lithium-containing layered oxide Li a N ab M c O 2±α (0.5 ≦ a ≦ 1.3, 0 ≦ b ≦ 0.01, 0.9 ≦ c ≦ 1.1, 0 ≦ α ≦ 0.3, M = at least one element selected from manganese, cobalt, nickel, iron, aluminum, molybdenum, zirconium, magnesium). When the potential P(V) is in the range of 4.8 ≦ P ≦ 5.0 (vs. Li / Li+), and the molar ratios of lithium and M are a and c, respectively, and when c is converted to 1.0, the ratio of a is in the range of 0.08 ≦ a ≦ 0.12. A positive electrode active material for a non-aqueous electrolyte secondary battery."

Prior Art Documents

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-186937 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-92824 Summary of the Invention [Problem to be solved by the invention]

[0004] The stoichiometric composition of lithium composite oxides with O2-type structure is Li 2 / 3 Since it is MeO2 (Me is a metal element other than Li), the amount of Li in the battery can become insufficient, limiting the charge and discharge capacity. Here, in order to further increase the discharge and charge capacity, there is a method of directly pre-doping Li into the positive electrode active material, but this method makes it easy for Li to penetrate into the transition metal layer of the lithium composite oxide, and the capacity retention rate of the battery is likely to decrease when discharge and charge are repeated.

[0005] Therefore, an object of one embodiment of the present disclosure is to provide a positive electrode active material that can provide a battery having a high initial discharge capacity and a high capacity retention rate after repeated discharge and charge. Another problem to be solved by another embodiment of the present disclosure is to provide a positive electrode material that can provide a battery having a high initial discharge capacity and a high capacity retention rate after repeated discharge and charge. Another problem to be solved by another embodiment of the present disclosure is to provide a positive electrode layer that can provide a battery with a high initial discharge capacity and a high capacity retention rate after repeated discharge and charge. Another problem to be solved by another embodiment of the present disclosure is to provide a solid-state battery that has a high initial discharge capacity and a high capacity retention rate after repeated discharge and charge. Another embodiment of the present disclosure aims to solve a problem by providing a method for manufacturing a solid-state battery that can provide a solid-state battery having a high initial discharge capacity and a high capacity retention rate after repeated discharge and charge. [Means for solving the problem]

[0006] The means for solving the above problems include the following means. <1> a lithium composite oxide having at least one structure selected from an O2 type structure, a T#2 type structure, and an O6 type structure, When the sum of the contents of metals other than Li and Na is 1, the Li content is 0.90 or more and 1.04 or less, The luminance at the maximum of three consecutive peaks in a one-dimensional luminance spectrum Maximum I max against Minimum I min When a total of 75 ratios are calculated, Maximum I max against Minimum I min The ratio of the positive electrode active material having a value of 0.3 or less is 2 or less out of 75. <2> It is a compound represented by the following formula 1 <1> The positive electrode active material according to claim 1. Formula 1: Li a Na b Mn x-p Ni y-q Co z-r M p+q+r O2 (In the above formula 1, a, b, x, y, z, p, q, and r are numbers that satisfy 0.9≦a≦1.04, 0≦b≦0.05, x+y+z=1, and 0≦p+q+r≦0.20, M represents at least one selected from the group consisting of Li, B, Mg, Al, K, Ca, Ti, Cr, Ga, Zr, Nb, Mo, and W. <3> In X-ray diffraction measurements, the intensity I of the peaks present in the 2θ range of 18° or more and less than 19° hi Intensity I of the peaks present in the 2θ range of 17° or more and less than 18° Lo The ratio is less than 5 <1> or <2> The positive electrode active material according to claim 1. <4> <1> ~ <3> A positive electrode material comprising the positive electrode active material according to any one of the above items. <5> <4> A positive electrode layer comprising the positive electrode material according to claim 1. <6> <1> ~ <3> 10. A solid-state battery comprising the positive electrode active material according to any one of claims 1 to 9. <7> Discharging a battery having a positive electrode layer containing a lithium composite oxide having at least one structure selected from an O2-type structure, a T#2-type structure, and a 6-type structure, a separator, and a negative electrode layer containing metallic lithium; removing the positive electrode layer from the battery, and stacking the removed positive electrode layer, an electrolyte layer or a separator, and a negative electrode layer in this order. [Effects of the Invention]

[0007] According to one embodiment of the present disclosure, a positive electrode active material is provided that allows for obtaining a battery that has a high initial discharge capacity and a high capacity retention rate after repeated discharge and charge. According to another embodiment of the present disclosure, there is provided a positive electrode material that can provide a battery that has a high initial discharge capacity and a high capacity retention rate after repeated discharge and charge. According to another embodiment of the present disclosure, there is provided a positive electrode layer that can provide a battery having a high initial discharge capacity and a high capacity retention rate after repeated discharge and charge. According to another embodiment of the present disclosure, a solid state battery is provided that has a high initial discharge capacity and a high capacity retention rate after repeated discharge and charge. According to another embodiment of the present disclosure, there is provided a method for manufacturing a solid-state battery that can obtain a solid-state battery that has a high initial discharge capacity and a high capacity retention rate after repeated discharge and charging. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic cross-sectional view showing an example of a solid-state battery. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of the present disclosure will be described. These descriptions and examples are intended to illustrate the embodiment and are not intended to limit the scope of the invention. In the present specification, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range. In addition, in the present specification, the upper or lower limit of a numerical range may be replaced with a value shown in the examples.

[0010] Each component may contain multiple types of the corresponding substance. When referring to the amount of each component in a composition, if there are multiple substances corresponding to each component in the composition, the amount refers to the total amount of those multiple substances present in the composition, unless otherwise specified. The term "process" includes not only independent processes but also processes that cannot be clearly distinguished from other processes as long as the intended effect of the process is achieved.

[0011] <Cathode active material> The positive electrode active material according to the present disclosure includes a lithium composite oxide having at least one structure selected from an O2 type structure, a T#2 type structure, and an O6 type structure, and when the sum of the contents of metals other than Li and Na is taken as 1, the Li content is 0.90 or more and 1.04 or less, and the luminance at the maximum values ​​of three consecutive peaks in a one-dimensional luminance spectrum is Maximum I max against Minimum I min If we calculate a total of 75 ratios, Maximum I max against Minimum I min The ratio of these is 0.3 or less in 2 out of 75 cases.

[0012] The positive electrode active material according to the present disclosure has the above-described configuration, and is a positive electrode active material that can provide a battery having a high initial discharge capacity and a high capacity retention rate after repeated discharge and charge. The reason for this is presumed to be as follows.

[0013] The positive electrode active material according to the present disclosure includes a lithium composite oxide having at least one structure selected from the group consisting of an O2-type structure, a T#2-type structure, and an O6-type structure. When the sum of the contents of metals other than Li and Na is taken as 1, the Li content is 0.90 or more and 1.04 or less. This increases the amount of Li in the composition of the positive electrode active material, resulting in a larger discharge and charge capacity. Furthermore, the luminance at the maximum values ​​of three consecutive peaks in a one-dimensional luminance spectrum is Maximum I max against Minimum I min If we calculate a total of 75 ratios, Maximum I max against Minimum I min By setting the ratio of the positive electrode active material to 2 or less out of 75, the amount of Li in the transition metal layer in the crystal structure of the positive electrode active material is reduced. When the amount of Li in the transition metal layer in the crystal structure of the positive electrode active material is reduced, the capacity retention rate after repeated charging and discharging is likely to increase. Therefore, the positive electrode active material according to the present disclosure has a high capacity retention rate even after repeated charging.

[0014] The positive electrode active material according to the present disclosure will be described below.

[0015] -Lithium composite oxide- The positive electrode active material according to the present disclosure contains a lithium composite oxide having at least one structure selected from the group consisting of an O2 type structure, a T#2 type structure, and an O6 type structure. Here, the O2 type structure is a structure that belongs to the space group P63mc, in which lithium is present at the center of an oxygen octahedron, and there are two types of overlapping between oxygen and transition metal per unit cell. The T#2 structure belongs to the space group Cmca, in which lithium is present at the center of an oxygen tetrahedron and there are two types of overlapping between oxygen and the transition metal per unit cell. The O6 type structure belongs to the space group R-3m, in which lithium is present at the center of the oxygen octahedron, and there are six different ways in which oxygen and transition metals overlap per unit cell.

[0016] -Li content- In the positive electrode active material according to the present disclosure, when the total content of metals other than Li and Na is taken as 1, the Li content is 0.90 or more and 1.04 or less. From the viewpoint of charge-discharge capacity, when the sum of the contents of metals other than Li and Na is taken as 1, the Li content is preferably 0.93 or more and 1.03 or less, more preferably 0.95 or more and 1.02 or less, and even more preferably 0.98 or more and 1.01 or less.

[0017] The total content of metals other than Li and Na and the Li content are measured by ICP optical emission spectroscopy. A measuring device such as Ultima Expert manufactured by Horiba, Ltd. can be used for ICP optical emission spectroscopy. The procedure for measuring the total content of metals other than Li and Na and the Li content is as follows. Approximately 10 mg of positive electrode active material is weighed out and dissolved in acid. If p + q + r = 0 in the following formula 1, sulfuric acid is used as the acid. In other cases, nitric acid, hot concentrated sulfuric acid, aqua regia, etc. is used depending on the contained elements. The solution dissolved in acid is introduced into an ICP-AES device to obtain the mass of each element contained in the solution. Assuming that x + y + z = 1, this is converted into the content of each metal other than Li and Na. The content of Li and Na is also converted under the same assumption.

[0018] - Maximum I max against Minimum I min Ratio of - The positive electrode active material according to the present disclosure has a luminance at the maximum value of three consecutive peaks in a one-dimensional luminance spectrum. Maximum I max against Minimum I min If we calculate a total of 75 ratios, Maximum I max against Minimum I minThe ratio of the maximum value of the peak is 0.3 or less in 2 or less out of 75. The brightness of the maximum value of the peak correlates with the amount of transition metal contained in that site. Therefore, the more transition metal present at an atomic site where a peak exists, the greater the brightness of the maximum value, and the greater the amount of Li, the smaller the brightness of the maximum value. In general, in layered compounds containing Li in the transition metal layer, sites containing a lot of Li and sites containing almost no Li are arranged periodically. The brightness at the maximum value of three consecutive peaks is Maximum I max against Minimum I min The ratio of is small when a site containing a large amount of Li is present among the three peaks, and is large when no such site is present.

[0019] Minimum I min and maximum value I max is measured using a transmission electron microscope. A JEM-ARM200F manufactured by JEOL Ltd. can be used as the transmission electron microscope. Maximum I max against Minimum I min The procedure for measuring the ratio will be described below. High-angle annular dark-field scanning transmission electron microscope (HAADF-STEM) images were obtained over a 10 nm x 10 nm area of ​​the surface of the positive electrode active material at an accelerating voltage of 200 kV, an electron beam incident direction of <1-10>, and a resolution of 0.2 nm or less, with both vertical and horizontal resolutions of 512 or greater. Five HAADF-STEM images were obtained, one for each of five different positive electrode active materials. Three one-dimensional brightness spectra were then obtained by integrating over 0.47 nm in the

[0001] direction in three random regions that did not contain one-dimensional or higher lattice defects such as dislocations, stacking faults, pores, or grain boundaries. Since there were five HAADF-STEM images, a total of 15 one-dimensional brightness spectra were obtained. In any one-dimensional luminance spectrum, the luminance at the maximum value of the peaks that exist at a period of 0.2 nm or less is obtained for three consecutive peaks. If there are no peaks at a period of 0.2 nm or less, a total of three luminances are obtained: the luminance of two adjacent peaks and the luminance at the midpoint between the two peaks. The maximum value of the obtained three luminances is called the maximum value I. max The minimum value is the minimum value I min And, Maximum I max against Minimum I min The ratio ( Minimum I min / Maximum I max ) is calculated in different regions of the same one-dimensional radiance spectrum using the same procedure. Maximum I max against Minimum I min The ratio ( Minimum I min / Maximum I max ) is calculated, and a total of five values ​​are calculated for each one-dimensional radiance spectrum. Maximum I max against Minimum I min The ratio ( Minimum I min / Maximum I max ) is calculated. For the remaining one-dimensional radiance spectra, the same procedure is used to obtain a total of five values ​​per one-dimensional radiance spectrum. Maximum I max against Minimum I min The ratio ( Minimum I min / Maximum I max ) and calculate a total of 75 Maximum I max against Minimum I min The ratio ( Minimum I min / Maximum I max ) is calculated. Maximum I max against Minimum I minCheck whether the ratio of 0.3 or less is 2 or less out of 75.

[0020] The above ratio is preferably 1 in 75 or less, and more preferably 0 in 75.

[0021] -Composition formula of positive electrode active material- From the viewpoint of the initial discharge capacity and the capacity retention rate, the positive electrode active material according to the present disclosure is preferably a compound represented by the following formula 1. Formula 1: Li a Na b Mn x-p Ni y-q Co z-r M p+q+r O2 In the above formula 1, a, b, x, y, z, p, q, and r are numbers that satisfy 0.9≦a≦1.04, 0≦b≦0.05 (preferably 0≦b≦0.03), x+y+z=1, and 0≦p+q+r≦0.20 (preferably 0≦p+q+r≦0.10), and M represents at least one element selected from the group consisting of B, Mg, Al, K, Ca, Ti, Cr, Ga, Zr, Nb, Mo, and W. M represents at least one selected from the group consisting of B, Mg, Al, K, Ca, Ti, Cr, Ga, Zr, Nb, Mo and W.

[0022] x is preferably a number that satisfies 0≦x≦1, and more preferably a number that satisfies 0.1≦x≦1. y is preferably a number that satisfies 0≦y≦0.5, and more preferably a number that satisfies 0≦y≦0.33. It is preferable that z is a number that satisfies 0≦z≦1, and it is more preferable that z is a number that satisfies 0≦z≦0.67. It is preferable that p is a number that satisfies 0≦p≦0.10. It is preferable that q is a number that satisfies 0≦q≦0.10. It is preferable that r is a number that satisfies 0≦r≦0.10.

[0023] -Intensity I hi and Intensity ILo - From the viewpoint of the initial discharge capacity and capacity retention rate, the intensity I of the peak present in the 2θ range of 18° or more and less than 19° in X-ray diffraction measurement hi The intensity I of the peaks present in the 2θ range of 17° or more and less than 18° Lo The ratio is preferably 5 or less, more preferably 3 or less, and even more preferably 2 or less.

[0024] Strength I hi and Intensity I Lo is measured by X-ray diffraction measurement. The X-ray diffraction measurement device that can be used is Rigaku Corporation, product name RINT-2000. Hereinafter, the intensity I hi and Intensity I Lo The measurement procedure will be explained. The maximum intensity of the peak with the greatest intensity among the peaks present in the range of 17° to less than 18° in the X-ray diffraction measurement results obtained under conditions of 0.01° step and 0.1 seconds / step or more so as to include at least the range of 2θ from 10° to 20° is defined as I. LO The intensity of the peaks in the range of 18° to 19° from the measurement results is defined as I HI Let's say.

[0025] -Specific examples of positive electrode active materials- The positive electrode active material according to the present disclosure is specifically Li 1.0 Na 0.0 Mn 0.5 Ni 0.2 Co 0.3 O2, Li 1.0 Na 0.0 Mn 0.4 Ni 0.2 Co 0.3 Cr 0.1 O2, Li 1.0 Na 0.0 Mn 0.67 Ni 0.33 Co 0.0 O2, Li 0.95 Na 0.05 Mn 0.5 Ni 0.2 Co 0.3 O2, Li 1.04 Na0.00 Mn 0.5 Ni 0.2 Co 0.3 O2, Li 1.0 Na 0.0 Mn 0.5 Ni 0.1 Co 0.3 Mg 0.1 Examples include O2.

[0026] <Cathode materials> The positive electrode material according to the present disclosure contains a positive electrode active material, and may contain a conductive additive, a solid electrolyte, a binder, and other components as necessary.

[0027] (Cathode active material) The positive electrode active material included in the positive electrode material according to the present disclosure is the positive electrode active material according to the present disclosure, and the same applies to preferred aspects.

[0028] The positive electrode active material contained in the positive electrode material according to the present disclosure may contain a positive electrode active material other than the positive electrode active material according to the present disclosure. The other positive electrode active material preferably includes a lithium composite oxide. The lithium composite oxide may contain at least one element selected from the group consisting of F, Cl, N, S, Br, and I. The lithium composite oxide may have a crystal structure belonging to at least one space group selected from the space groups R-3m, Immm, and P63-mmc (also referred to as P63mc or P6 / mmc). The lithium composite oxide may have an O2-type structure in which the transition metal, oxygen, and lithium are primarily arranged.

[0029] Examples of lithium composite oxides having a crystal structure belonging to R-3m include Li x Me y O α X β(Me represents at least one selected from the group consisting of Mn, Co, Ni, Fe, Al, Cu, V, Nb, Mo, Ti, Cr, Zr, Zn, Na, K, Ca, Mg, Pt, Au, Ag, Ru, W, B, Si, and P, and X represents at least one selected from the group consisting of F, Cl, N, S, Br, and I, and satisfy the conditions 0.5≦x≦1.5, 0.5≦y≦1.0, 1≦α<2, and 0<β≦1.)

[0030] Examples of lithium composite oxides having a crystal structure belonging to Immm include Li x1 M 1 A 1 2(1.5≦x1≦2.3, M 1 contains at least one selected from the group consisting of Ni, Co, Mn, Cu and Fe, and A 1 contains at least oxygen, and A 1 The ratio of oxygen in the oxide is 85 atomic % or more. x1 M 1A 1-x2 M 1B x2 O 2-y A 2 y (0≦x2≦0.5, 0≦y≦0.3, and at least one of x2 and y is not 0, and M 1A represents at least one selected from the group consisting of Ni, Co, Mn, Cu, and Fe, and M 1B represents at least one selected from the group consisting of Al, Mg, Sc, Ti, Cr, V, Zn, Ga, Zr, Mo, Nb, Ta and W, and A2 represents at least one selected from the group consisting of F, Cl, Br, S and P.

[0031] Examples of lithium composite oxides having a crystal structure belonging to P63-mmc include M1 x M2 yO2 (where M1 represents an alkali metal (preferably at least one of Na and K), M2 represents a transition metal (preferably at least one selected from the group consisting of Mn, Ni, Co, and Fe), and 0 < x + y ≤ 2). Examples of the composite oxide include those represented by this formula.

[0032] As the lithium composite oxide having an O2-type structure, for example, Li x [Li α (Mn a Co b M c ) 1-α O2 (where 0.5 < x < 1.1, 0.1 < α < 0.33, 0.17 < a < 0.93, 0.03 < b < 0.50, 0.04 < c < 0.33, and M represents at least one selected from the group consisting of Ni, Mg, Ti, Fe, Sn, Zr, Nb, Mo, W, and Bi). Examples of the composite oxide include those represented by this formula, and specific examples include Li 0.744 [Li 0.145 Mn 0.625 Co 0.115 Ni 0.115 O2 and the like.

[0033] A more preferred embodiment is that at least a part of the surface of the positive electrode active material is coated with a sulfide solid electrolyte, an oxide solid electrolyte, or a halide solid electrolyte. As the halide solid electrolyte for coating at least a part of the surface of the positive electrode active material, Li 6-(4-x)b (Ti 1-x Al x ) b F6 (where 0 < x < 1, 0 < b ≤ 1.5) [LTAF electrolyte] is preferred.

[0034] (Conductive aid) Examples of the conductive aid include carbon materials, metal materials, and conductive polymer materials. Examples of the carbon materials include carbon black (e.g., acetylene black, furnace black, ketjen black, etc.), fibrous carbon (e.g., vapor-grown carbon fiber, carbon nanotube, carbon nanofiber, etc.), graphite, carbon fluoride, etc. Examples of the metal materials include metal powder (e.g., aluminum powder, etc.), conductive whisker (e.g., zinc oxide, potassium titanate, etc.), conductive metal oxide (e.g., titanium oxide, etc.), etc. Examples of the conductive polymer materials include polyaniline, polypyrrole, polythiophene, etc. The conductive aid may be used alone as only one type, or two or more types may be mixed and used.

[0035] (Solid electrolyte) As the solid electrolyte, it is preferable to contain at least one solid electrolyte species selected from the group of solid electrolytes consisting of sulfide solid electrolytes, oxide solid electrolytes, and halide solid electrolytes.

[0036] As the sulfide solid electrolyte, it preferably contains sulfur (S) as the main component of the anion element, and further preferably contains, for example, Li element and A element. The A element is at least one selected from the group consisting of P, As, Sb, Si, Ge, Sn, B, Al, Ga, and In. The sulfide solid electrolyte may further contain at least one of O and halogen elements. Examples of the halogen element (X) include F, Cl, Br, I, etc. The composition of the sulfide solid electrolyte is not particularly limited, and examples include xLi2S·(100-x)P2S5 (70≦x≦80), yLiI·zLiBr·(100-y-z)(xLi2S·(1-x)P2S5) (0.7≦x≦0.8, 0≦y≦30, 0≦z≦30). The sulfide solid electrolyte may have a composition represented by the following general formula (1). Li 4-x Ge 1-x P x S4(0<x<1) ··· Formula (1) In formula (1), at least a portion of the Ge may be substituted with at least one selected from the group consisting of Sb, Si, Sn, B, Al, Ga, In, Ti, Zr, V, and Nb. At least a portion of the P may be substituted with at least one selected from the group consisting of Sb, Si, Sn, B, Al, Ga, In, Ti, Zr, V, and Nb. At least a portion of the Li may be substituted with at least one selected from the group consisting of Na, K, Mg, Ca, and Zn. At least a portion of the S may be substituted with a halogen. The halogen is at least one of F, Cl, Br, and I.

[0037] The oxide solid electrolyte contains oxygen (O) as the main anion element, and may also contain Li and Q elements (Q represents at least one of Nb, B, Al, Si, P, Ti, Zr, Mo, W, and S). Examples of the oxide solid electrolyte include garnet-type solid electrolytes, perovskite-type solid electrolytes, Nasicon-type solid electrolytes, Li-PO-based solid electrolytes, and Li-BO-based solid electrolytes. Examples of the garnet-type solid electrolyte include Li7La3Zr2O 12 , Li 7-x La3(Zr 2-x Nb x )O 12 (0≦x≦2), Li5La3Nb2O 12 Examples of perovskite-type solid electrolytes include (Li,La)TiO3, (Li,La)NbO3, (Li,Sr)(Ta,Zr)O3, etc. Examples of Nasicon-type solid electrolytes include Li(Al,Ti)(PO4)3, Li(Al,Ga)(PO4)3, etc. Examples of Li-PO-based solid electrolytes include Li3PO4 and LIPON (a compound in which part of the O in Li3PO4 is substituted with N), and examples of Li-BO-based solid electrolytes include Li3BO3 and a compound in which part of the O in Li3BO3 is substituted with C, etc.

[0038] As the halide solid electrolyte, a solid electrolyte containing Li, M, and X (M represents at least one of Ti, Al, and Y, and X represents F, Cl, or Br) is suitable. 6-3z Y zX6 (where X represents Cl or Br, and z satisfies 0 < z < 2), Li 6-(4-x)b (Ti 1-x Al x ) b F6 (0 < x < 1, 0 < b ≤ 1.5) is preferred. Li 6-3z Y z Among X6, Li3YX6 (where X represents Cl or Br) is more preferred in terms of excellent lithium ion conductivity, and further Li3YCl6 is preferred. Also, Li 6-(4-x)b (Ti 1-x Al x ) b F6 (0 < x < 1, 0 < b ≤ 1.5) is preferably included together with a solid electrolyte such as a sulfide solid electrolyte from viewpoints such as suppressing oxidative decomposition of the sulfide solid electrolyte.

[0039] (Binder) Examples of the binder include vinyl halide resins, rubbers, polyolefin resins, etc. Examples of the vinyl halide resin include polyvinylidene fluoride (PVdF), a copolymer of polyvinylidene fluoride and hexafluoropropylene (PVdF-HFP), etc. Examples of the polyolefin resin include butadiene rubber (BR), acrylate butadiene rubber (ABR), styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), butyl rubber (isobutylene-isoprene rubber), etc. Examples of the polyolefin resin include polyethylene, polypropylene, etc. The binder may be a diene-based rubber containing a double bond in the main chain, for example, a butadiene-based rubber in which butadiene occupies 30 mol% or more of the whole.

[0040] (Other components) Examples of the other components include oxide solid electrolytes, halide solid electrolytes, thickeners, surfactants, dispersants, wetting agents, defoamers, solvents, etc.

[0041] <Solid battery> The solid battery according to the present disclosure contains the positive electrode active material according to the present disclosure. The solid-state battery according to the present disclosure preferably includes a positive electrode layer, a negative electrode layer, and an electrolyte layer or a separator disposed between the positive electrode layer and the negative electrode layer, and the positive electrode layer preferably contains the positive electrode material according to the present disclosure.

[0042] (Battery structure) Solid-state batteries include so-called all-solid-state batteries (in which the content of electrolytic solution as electrolyte is less than 10 mass % of the total amount of electrolyte) that use an inorganic solid electrolyte as the electrolyte. The structure of the solid-state battery of the present disclosure may include a positive electrode current collector, a positive electrode layer, a solid electrolyte layer, a negative electrode layer, and a negative electrode current collector in this order, for example, as shown in FIG. 1. The solid electrolyte layer B in FIG. 1 may have a two-layer structure. FIG. 1 is a schematic cross-sectional view showing an example of a solid-state battery. The solid-state battery shown in FIG. 1 includes an anode including a negative electrode current collector 113 and a negative electrode layer A, a solid electrolyte layer B, a positive electrode including a positive electrode current collector 115 and a positive electrode layer C, and anode layer A. The negative electrode layer A includes a negative electrode active material 101, a conductive additive 105, a binder 109, and a solid electrolyte 102. The positive electrode layer C includes a positive electrode active material 103, a binder 111, and a solid electrolyte 102.

[0043] When a set of a positive electrode layer, a solid electrolyte layer, and a negative electrode layer is defined as a power generation unit, the solid-state battery may have only one power generation unit or may have two or more power generation units. When the solid-state battery has two or more power generation units, the power generation units may be connected in series or in parallel.

[0044] The solid-state battery may be configured by sealing the end faces (side faces) of the stacked structure of the positive electrode layer / solid electrolyte layer / negative electrode layer with resin. The electrode current collector may have a buffer layer, an elastic layer, or a PTC (Positive Temperature Coefficient) thermistor layer disposed on the surface. The shape of the solid-state battery is not particularly limited, and may be, for example, a coin type, a cylindrical type, a square type, a sheet type, a button type, a flat type, or a laminate type.

[0045] (Electrolyte layer and separator) A solid-state battery includes an electrolyte layer or separator.

[0046] The electrolyte layer may be a layer containing a solid electrolyte. In the case of a layer containing a solid electrolyte (solid electrolyte layer), the solid electrolyte layer preferably contains one selected from the group consisting of a sulfide solid electrolyte, an oxide solid electrolyte, and a halide solid electrolyte. Specific examples of the sulfide solid electrolyte, oxide solid electrolyte, and halide solid electrolyte are the same as those described above.

[0047] The solid electrolyte layer may have a single layer structure or a multi-layer structure of two or more layers.

[0048] The solid electrolyte layer may contain a binder, or may not contain a binder. The binder that can be contained in the solid electrolyte layer is the same as the binder described above.

[0049] As the separator, a porous sheet (film) made of a resin such as polyethylene (PE), polypropylene (PP), polyester, cellulose, or polyamide can be used.

[0050] (positive electrode layer) The solid-state battery includes a positive electrode layer, which includes the positive electrode material of the present disclosure.

[0051] (Positive electrode current collector) The solid-state battery may further include a positive electrode current collector that collects current from the positive electrode layer and is disposed on the opposite side of the positive electrode layer from the solid electrolyte layer. The positive electrode current collector may be made of, for example, stainless steel, aluminum, copper, nickel, iron, titanium, or carbon, and is preferably an aluminum alloy foil or aluminum foil. The aluminum alloy foil or aluminum foil may be manufactured using powder. The positive electrode current collector may be, for example, in the form of a foil or a mesh. The positive electrode current collector may have a buffer layer, an elastic layer, or a PTC (Positive Temperature Coefficient) thermistor layer disposed on the surface thereof.

[0052] (negative electrode layer) The solid-state battery includes a negative electrode layer. The negative electrode layer contains a negative electrode active material. The negative electrode layer may contain at least one of a negative electrode solid electrolyte, a conductive additive, and a binder, as needed. Examples of negative electrode active materials include Li-based active materials such as metallic lithium, carbon-based active materials such as graphite, oxide-based active materials such as lithium titanate, and Si-based active materials such as elemental Si. The conductive additive, negative electrode solid electrolyte, and binder used in the negative electrode layer may be the same as those exemplified as the conductive additive contained in the positive electrode layer, the solid electrolyte contained in the solid electrolyte layer, and the binder.

[0053] (Negative electrode current collector) The solid-state battery may further include a negative electrode current collector that collects current from the negative electrode layer and is disposed on the opposite side of the negative electrode layer from the solid electrolyte layer. The negative electrode current collector may be made of, for example, stainless steel, aluminum, copper, nickel, iron, titanium, or carbon, with copper being preferred. The negative electrode current collector may be in the form of, for example, a foil or mesh. The negative electrode current collector may have a buffer layer, an elastic layer, or a PTC (Positive Temperature Coefficient) thermistor layer disposed on the surface thereof.

[0054] <Solid-state battery manufacturing method> The method for producing a solid-state battery according to the present disclosure includes a step of discharging a battery having a positive electrode layer containing a lithium composite oxide having at least one structure selected from an O2-type structure, a T#2-type structure, and a 6-type structure, and a negative electrode layer containing metallic lithium (doping step); The method includes a step of removing the positive electrode layer from the battery, and laminating the removed positive electrode layer, an electrolyte layer or a separator, and a negative electrode layer in this order (lamination step). The method for manufacturing a solid-state battery according to the present disclosure may include other steps, such as a step of housing the battery in a case, in addition to the steps described above.

[0055] (Doping process) The doping step is a step of discharging a battery having a positive electrode layer containing a lithium composite oxide having at least one structure selected from the group consisting of an O2-type structure, a T#2-type structure, and a 6-type structure, a separator, and a negative electrode layer containing metallic lithium.

[0056] -Positive electrode layer manufacturing procedure- The procedure for producing the positive electrode layer used in the doping step will be described. The positive electrode layer used in the doping step contains a lithium composite oxide having at least one structure selected from the group consisting of an O2-type structure, a T#2-type structure, and a 6-type structure, and may contain a conductive additive, a solid electrolyte, a binder, and other components as necessary. The positive electrode layer is preferably produced by kneading the components that can be contained in the positive electrode layer to obtain a slurry, applying the slurry to a substrate, drying the slurry, and pressing the resulting dried film.

[0057] The method for kneading the components that can be contained in the positive electrode layer when obtaining the slurry is not particularly limited, and examples thereof include a method of kneading using a kneading device, such as an ultrasonic homogenizer, a shaker, a thin film rotary mixer, a dissolver, a homomixer, a kneader, a roll mill, a sand mill, an attritor, a ball mill, a vibrator mill, and a high-speed impeller mill.

[0058] Methods for pressing the dried film include roll pressing and cold isostatic pressing (CIP).

[0059] The pressure during pressing is preferably 0.1 ton / cm 2 More than 0.5t / cm 2 More preferably, 1 t / cm 2 The pressure during pressing is preferably 10 t / cm 2 Less than 8t / cm, preferably 8t / cm 2Less than 6t / cm, more preferably 2 The following is the result.

[0060] The lithium composite oxide having at least one structure selected from the O2-type structure, the T#2-type structure, and the 6-type structure contained in the positive electrode layer used in the doping step is preferably prepared by ion-exchanging Na contained in the Na-doped precursor with Li.

[0061] The Na-doped precursor may be a sodium composite oxide having a P2 structure belonging to the space group P63 / mmc. The sodium composite oxide may be, for example, a compound represented by the following formula 2. Formula 2: Na c Mn x-p Ni y-q Co z-r M p+q+r O2 In the above formula 2, c, x, y, z, p, q, and r are numbers that satisfy 0≦c≦1 (preferably 0.6≦c≦0.9), x+y+z=1, and 0≦p+q+r≦0.20 (preferably 0≦p+q+r≦0.1), M represents at least one selected from the group consisting of Li, B, Mg, Al, K, Ca, Ti, Cr, Ga, Zr, Nb, Mo, and W. x is preferably a number that satisfies 0≦x≦1, and more preferably a number that satisfies 0.1≦x≦1. y is preferably a number that satisfies 0≦y≦0.5, and more preferably a number that satisfies 0≦y≦0.33. It is preferable that z is a number that satisfies 0≦z≦1, and it is more preferable that z is a number that satisfies 0≦z≦0.67. It is preferable that p is a number that satisfies 0≦p≦0.10. It is preferable that q is a number that satisfies 0≦q≦0.10. It is preferable that r is a number that satisfies 0≦r≦0.10.

[0062] Ion exchange of the Na-doped precursor can be performed using a molten salt bed containing a mixture of lithium nitrate and lithium chloride. The temperature conditions during ion exchange are preferably in the range of not less than the temperature at which the molten salt bed melts but less than 320°C.

[0063] -battery- The battery used in the doping process will be described. The battery used in the doping step has the positive electrode layer prepared by the above procedure, a separator, and a negative electrode layer containing metallic lithium.

[0064] As the separator, a porous sheet (film) made of a resin such as polyethylene (PE), polypropylene (PP), polyester, cellulose, or polyamide can be used. The negative electrode layer contains metallic lithium. From the viewpoint of efficiency of the doping process, the negative electrode layer is preferably made of metallic lithium.

[0065] The battery used in the doping step may further contain a non-aqueous electrolyte solution. The non-aqueous electrolyte is not particularly limited, and any conventionally known non-aqueous electrolyte can be used. The non-aqueous electrolyte preferably contains a non-aqueous solvent and a supporting salt. Examples of the non-aqueous solvent include carbonates such as ethylene carbonate, diethyl carbonate, dimethyl carbonate, and ethyl methyl carbonate, as well as ethers and esters. Examples of the supporting salt include lithium salts such as LiPF6 and LiBF4.

[0066] The battery used in the doping step preferably further contains a positive electrode current collector. The positive electrode current collector may be the same as the positive electrode current collector applied to the solid state battery according to the present disclosure described above.

[0067] The battery used in the doping step is preferably produced by laminating a positive electrode current collector, a positive electrode layer, a separator, and a negative electrode layer in this order to obtain an electrode body, and then housing the electrode body and the nonaqueous electrolyte solution in a battery case (external container).

[0068] -Discharge- In the doping step, the battery fabricated by the above procedure is discharged. By discharging the produced battery, lithium ions are doped from the negative electrode layer into the positive electrode active material, and the lithium content of the positive electrode active material increases.

[0069] The battery is preferably discharged, for example, at a current of 0.01 C to 0.2 C to a voltage of 1 V to 3 V. Furthermore, it is preferable that the discharge be maintained at 1 V to 3 V until the final current reaches 0.05 C to 0.02 C.

[0070] (Lamination process) The lamination step is a step of removing the positive electrode layer from the battery, and laminating the removed positive electrode layer, an electrolyte layer or a separator, and a negative electrode layer in this order.

[0071] -Extraction of the positive electrode layer- In the lamination step, the positive electrode layer is removed from the battery that has undergone the doping step. The method for removing the positive electrode layer is not particularly limited, but it is preferable to remove the positive electrode layer by disassembling the battery.

[0072] -Lamination of a positive electrode layer, an electrolyte layer (or separator), and a negative electrode layer- In the lamination step, the removed positive electrode layer, an electrolyte layer or a separator, and a negative electrode layer are laminated in this order.

[0073] As the electrolyte layer and the negative electrode layer, the electrolyte layer and the negative electrode layer that are applied to the solid state battery according to the present disclosure described above are applied. The method for producing the electrolyte layer and the negative electrode layer is not particularly limited, and it is preferable to produce them by kneading the components that can be contained in the electrolyte layer and the negative electrode layer to obtain a slurry, applying the slurry to a substrate, drying it, and pressing the resulting dried film. A commercially available porous sheet (film) can be used as the separator. The removed positive electrode layer, an electrolyte layer or a separator, and a negative electrode layer are then stacked in this order, and pressed as necessary to obtain a laminate (electrode body).

[0074] It is preferable to fabricate the solid state battery according to the present disclosure through the above steps. [Example]

[0075] Examples will be described below, but the present invention is not limited to these examples. In the following description, unless otherwise specified, all "parts" and "%" are by mass.

[0076] <Preparation of lithium composite oxide contained in the positive electrode layer used in the doping process>

[0077] (Preparation of lithium composite oxide 1) - Preparation of Na-doped precursor - Mn(NO3)2·6H2O, Ni(NO3)2·6H2O, and Co(NO3)2·6H2O were used as raw materials and dissolved in pure water to achieve a molar ratio of Mn, Ni, and Co of 5:2:3. A 12% by mass Na2CO3 solution was prepared, and these two solutions were simultaneously titrated into a beaker. The titration rate was controlled to maintain a pH between 7.0 and 7.1. After the titration, the mixed solution was stirred at 50°C and 300 rpm for 24 hours. The resulting reaction product was washed with pure water, and the precipitated powder was separated by centrifugation. The resulting powder was dried at 120°C for 48 hours and then crushed in an agate mortar to obtain a powder. The obtained powder was added with Na2CO3 in a composition ratio of Na 0.75 Mn 0.5 Ni 0.2 Co 0.3 The Na-doped precursor was synthesized by cold isostatic pressing under a load of 2 tons. The resulting pellets were pre-baked in air at 600°C for 6 hours and then sintered at 700°C for 24 hours. The pellets were then cooled to 250°C at a rate of 3°C / min and allowed to cool.

[0078] -Preparation of lithium composite oxide- LiNO3 and LiCl were mixed at a mass ratio of 88:12 to obtain a mixed powder. The Na-doped precursor was weighed so that the ratio of the number of moles of Li contained in the mixed powder was 10 times the number of moles of the Na-doped precursor. The Na-doped precursor and the mixed powder were mixed, and ion exchange was carried out in air at 280°C for 1 hour. After the ion exchange, water was added to dissolve the salt, and the mixture was washed with water to obtain a lithium composite oxide 1(Li) with an O2 structure. 0.65 Mn 0.5 Ni 0.2 Co 0.3 O2) was obtained.

[0079] (Preparation of lithium composite oxide 2) In the preparation of lithium composite oxide, lithium composite oxide 2 (Li) with an O2-type structure was prepared by the same procedure as in the preparation of lithium composite oxide 1, except that LiI was used instead of LiCl. 0.91 Mn 0.5 Ni 0.2 Co 0.3 O2) was obtained.

[0080] (Preparation of lithium composite oxide 3) Lithium composite oxide 3 (Li) with an O2-type structure was prepared by the same procedure as in (Preparation of lithium composite oxide 1), except that the procedure in "Preparation of Na-doped precursor" was changed as follows: 0.1 Na 0.75 Mn 0.55 Ni 0.1 Co 0.25 O2) was obtained.

[0081] - Preparation of Na-doped precursor - Mn(NO3)2·6H2O, Ni(NO3)2·6H2O, and Co(NO3)2·6H2O were used as raw materials and dissolved in pure water to a molar ratio of Mn, Ni, and Co of 55:10:25. A 12% by mass Na2CO3 solution was prepared, and these two solutions were simultaneously titrated into a beaker. The titration rate was controlled to maintain a pH between 7.0 and 7.1. After the titration, the mixed solution was stirred at 50°C and 300 rpm for 24 hours. The resulting reaction product was washed with pure water, and the precipitated powder was separated by centrifugation. The resulting powder was dried at 120°C for 48 hours and then crushed in an agate mortar to obtain a powder. The obtained powder was mixed with Na2CO3 and Li2CO3 in a composition ratio of Li 0.1 Na 0.75 Mn 0.55 Ni 0.1 Co 0.25 The Na-doped precursor was synthesized by cold isostatic pressing under a load of 2 tons. The resulting pellets were pre-baked in air at 600°C for 6 hours and then sintered at 700°C for 24 hours. The pellets were then cooled to 250°C at a rate of 3°C / min and allowed to cool.

[0082] Example 1 (Doping process) -Creating the positive electrode layer- 85 g of the lithium composite oxide 1 (powdered by ball milling) obtained by the above procedure and 10 g of carbon black (conductive additive) were added to 125 mL of n-methylpyrrolidone solution containing 5 g of polyvinylidene fluoride (PVDF) as a binder, and the mixture was kneaded until uniformly mixed to prepare a slurry. This slurry was applied to a 15 μm thick Al current collector as a substrate with a basis weight of 6 mg / cm. 2 The electrode was then pressed to a thickness of 45 μm and a density of 2.4 g / cm. 3 Finally, this electrode was cut into a circle having a diameter of 16 mm to obtain a positive electrode including a positive electrode layer and a positive electrode current collector.

[0083] -Creating the negative electrode layer- The Li foil was cut to a diameter of 19 mm to obtain a negative electrode layer.

[0084] -Battery manufacturing- A CR2032 coin cell battery was fabricated using the resulting positive and negative electrode layers. A porous PP sheet was used as the separator, and the nonaqueous electrolyte was a mixture of EC (ethylene carbonate) and DMC (dimethyl carbonate) in a volume ratio of 3:7, with lithium hexafluorophosphate (LiPF6) dissolved at a concentration of 1 mol / L as the supporting electrolyte.

[0085] -Discharge- The fabricated battery was discharged to 2.0 V at 0.1 C, and then held at 2.0 V until the final current was 0.01 C, thereby doping with lithium ions. The discharge time was 512 minutes.

[0086] (Lamination process) -Removal of the positive electrode- After discharging, the battery was disassembled, and the positive electrode having the positive electrode layer and the positive electrode current collector was taken out.

[0087] -Preparing the separator- A separator was obtained by cutting a porous PP sheet into a piece having a diameter of 19 mm.

[0088] -Preparation of the negative electrode layer- A 1 mm thick Li foil was cut to have a diameter of 19 mm to obtain a negative electrode layer.

[0089] -Lamination of positive electrode layer, electrolyte layer, and negative electrode layer- The removed positive electrode, separator, and negative electrode layer were stacked in this order to obtain a laminate. The positive electrode was stacked so that the positive electrode layer faced the separator. The laminate and a nonaqueous electrolyte (a mixture of EC (ethylene carbonate) and DMC (dimethyl carbonate) in a volume ratio of 3:7, with lithium hexafluorophosphate (LiPF6) dissolved at a concentration of 1 mol / L as a supporting electrolyte) were placed in a coin cell to prepare a CR2032 coin cell battery.

[0090] <Example 2> A CR2032 coin cell battery was produced in the same manner as in Example 1, except that the discharging step in the doping step was changed to the following procedure. -Discharge- A voltage sweep was performed from the open circuit voltage (OCV) to 1.5 V at a sweep rate of 5 mV / sec, and the voltage was held at 1.5 V for 10 minutes. The time required for discharge was 16 minutes.

[0091] <Comparative Example 1> A positive electrode was prepared according to the procedure of - Preparation of positive electrode layer - in (Doping step) of Example 1, and a battery was prepared according to the same procedure as (Lamination step) of Example 1, except that the above positive electrode was used instead of the positive electrode taken out by disassembling the battery in (Lamination step).

[0092] <Comparative Example 2> A positive electrode was produced in the same manner as in (Doping step) - Preparation of positive electrode layer - of Example 1, except that lithium composite oxide 2 was used instead of lithium composite oxide 1 in (Doping step) - Preparation of positive electrode layer - of Example 1, and a battery was produced in the same manner as in (Lamination step) of Example 1, except that the above positive electrode was used instead of the positive electrode taken out by disassembling the battery in (Lamination step).

[0093] <Comparative Example 3> A positive electrode was produced in the same manner as in (Doping step) - Preparation of positive electrode layer - of Example 1, except that lithium composite oxide 3 was used instead of lithium composite oxide 1 in (Doping step) - Preparation of positive electrode layer - of Example 1, and a battery was produced in the same manner as in (Lamination step) of Example 1, except that the above positive electrode was used instead of the positive electrode taken out by disassembling the battery in (Lamination step).

[0094] <Evaluation> (Li content, Minimum I min / Maximum I max , and intensity I Lo / Intensity I hi ) The positive electrode active material contained in the battery obtained in each example is "the Li content ("Li content" in Table 1) when the total content of metals other than Li and Na is set to 1" Maximum I max against Minimum I min The ratio of 0.3 or less (see " I min / I max "Proportion (pieces) where the value is 0.3 or less" and "Intensity I hi Intensity I Lo Ratio of Strength I in Table 1 Lo / Intensity I hi The results of calculating "")" according to the procedure described above are shown in Table 1.

[0095] (Initial discharge capacity) A charge-discharge test was carried out using a galvanostat under the conditions of a current of 0.1 C, a charge cut-off voltage of 4.8 V, and a discharge cut-off voltage of 2.0 V. Starting with charging, after the first charge was completed, the amount of current required for discharging down to 2.0 V was calculated, and the initial discharge capacity was calculated by dividing this by the weight of the active material used in the measurement.

[0096] (Capacity retention rate after 20 cycles) A charge-discharge test was carried out under the same conditions as above, and the first discharge capacity and the 20th discharge capacity were calculated. The 20th discharge capacity was divided by the first discharge capacity to obtain the capacity retention rate after 20 cycles.

[0097] [Table 1]

[0098] Table 1 shows the structure and composition formula of the positive electrode active material contained in the battery obtained in each example. In addition, the description of the structure as "O2+T#2 type" means that it has both the O2 type structure and the T#2 type structure.

[0099] From the above results, it is understood that the positive electrode active material of this example can provide a battery having a high initial discharge capacity and a high capacity retention rate after repeated discharge and charge. [Explanation of symbols]

[0100] A negative electrode layer B Solid electrolyte layer C positive electrode layer 101 Negative electrode active material 102 Solid electrolyte 103 Cathode active material 105 Conductive additives 109,111 binders 113 Negative electrode current collector 115 Positive electrode current collector

Claims

1. It contains a lithium composite oxide having at least one structure selected from an O2 type structure, a T#2 type structure, and an O6 type structure, the lithium composite oxide contains Ni, Co, and Mn, When the sum of the contents of metals other than Li and Na is 1, the Li content is 0.90 or more and 1.04 or less, The minimum luminance value I at the maximum of three consecutive peaks in a one-dimensional luminance spectrum ｍｉｎ Maximum value I for ｍａｘ When a total of 75 ratios are calculated, the minimum value I ｍｉｎ Maximum value I for ｍａｘ The ratio of the positive electrode active material having a value of 0.3 or less is 2 or less out of 75 positive electrode active materials.

2. The positive electrode active material according to claim 1 , which is a compound represented by the following formula 1: Formula 1: Li ａ Na ｂ Mn ｘ－ｐ Ni ｙ－ｑ Co ｚ－ｒ M ｐ＋ｑ＋ｒ O ２ (In the above formula 1, a, b, x, y, z, p, q, and r are numbers that satisfy 0.9≦a≦1.04, 0≦b≦0.05, x+y+z=1, and 0≦p+q+r≦0.20, M represents at least one element selected from the group consisting of B, Mg, Al, K, Ca, Ti, Cr, Ga, Zr, Nb, Mo, and W.

3. In X-ray diffraction measurement, the intensity I of the peak present in the range of 2θ of 18° or more and less than 19° ｈｉ The intensity I of the peak present in the range of 2θ of 17° or more and less than 18° Ｌｏ The positive electrode active material according to claim 2 , wherein the ratio of

4. A positive electrode material comprising the positive electrode active material according to any one of claims 1 to 3.

5. A positive electrode layer comprising the positive electrode material of claim 4 .

6. A solid state battery comprising the positive electrode active material according to any one of claims 1 to 3.

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