Method for producing metal complex compound, method for producing lithium metal complex oxide, and method for producing metal complex compound

Abstract

A metal complex compound in which the relative standard deviation of the volume-based crystallite diameter distribution calculated from the diffraction peaks in the range of 2θ = 19 ± 1° in powder X-ray diffraction measurement using CuKα rays is 0.50 or more.

Description

TECHNICAL FIELD

[0001] The present application relates to a metal complex compound, a manufacturing method of a lithium metal complex oxide, and a manufacturing method of a metal complex compound.

[0002] This application claims priority based on Japanese Patent Application No. 2021-042576 filed on March 16, 2021 and Japanese Patent Application No. 2022-015158 filed on February 2, 2022, and the contents thereof are hereby incorporated by reference. BACKGROUND

[0003] As a manufacturing method of a positive electrode active material for a lithium secondary battery, for example, there is a method of mixing a lithium compound and a metal complex compound containing a metal element other than Li and performing firing.

[0004] As a technique for improving the battery performance of a lithium secondary battery, attempts have been made to control the state of crystallization of a metal complex compound which is a raw material of a positive electrode active material.

[0005] For example, Patent Literature 1 discloses that if a precursor satisfying a specific half-value width in an X-ray diffraction profile using CuKα rays is used, it is possible to increase the capacity of a lithium secondary battery.

[0006] PRIOR ART DOCUMENTS

[0007] PATENT LITERATURE

[0008] Patent Literature 1: Japanese Patent Application Publication No. H10-310433 SUMMARY

[0009] PROBLEMS TO BE SOLVED BY THE INVENTION

[0010] The state of crystallization of a metal complex compound as a raw material is influenced by the state of crystallization of a positive electrode active material manufactured therefrom. Therefore, in order to further improve the battery performance of a lithium secondary battery, a metal complex compound whose state of crystallization is further controlled is required.

[0011] The present application was made in view of the above circumstances, and the object is to provide a metal complex compound which becomes a raw material of a positive electrode active material capable of manufacturing a lithium secondary battery having a high initial efficiency, a manufacturing method of a lithium metal complex oxide using the same, and a manufacturing method of a metal complex compound.

[0012] MEANS FOR SOLVING THE PROBLEMS

[0013] The present application includes [1] to

[10] .

[0014] [1] A metal complex compound, wherein a relative standard deviation of a volume-based crystallite diameter distribution calculated from diffraction peaks in a range of 2 theta = 19 ± 1° in powder X-ray diffraction measurement using CuKα rays is 0.50 or more.

[0015] [2] The metal complex compound according to [1], wherein a mode of the crystallite diameter distribution is or more.

[0016] [3] The metal complex compound according to [1] or [2], wherein an average crystallite diameter in the crystallite diameter distribution is or more.

[0017] [4] The metal complex compound according to any one of [1] to [3], wherein a ratio of the mode to the average crystallite diameter in the crystallite diameter distribution, i.e., mode / average crystallite diameter, is 0.57 or less.

[0018] [5] The metal complex compound according to any one of [1] to [4], which satisfies the following formula (A).

[0019]

[0020] (In formula (A), d10 is a crystallite diameter at which an area ratio with respect to a total area of a region surrounded by a crystallite diameter distribution function curve and a horizontal axis in the crystallite diameter distribution function curve with the volume-based crystallite diameter in the above-described crystallite diameter distribution as a horizontal axis and a probability density function of a crystallite with respect to the crystallite diameter as a vertical axis is 10% from a small-diameter side

[0021] d90 is a crystallite diameter at which the area ratio with respect to the total area is 90% from the small-diameter side )

[0022] [6] The metal complex compound according to any one of [1] to [5], which is represented by the following composition formula (I).

[0023] Ni 1-x-y Co x M y O z (OH) 2-α Formula (I)

[0024] (The composition formula (I) satisfies 0≤x≤0.5, 0≤y≤0.5, 0≤x+y<1, 0≤z≤3, -0.5≤α≤2, and α-z<2, M is one or more elements selected from the group consisting of Mn, Fe, Cu, Ti, Mg, Al, Zn, Sn, Zr, Nb, Ga, W, Mo, B, and Si.)

[0025] [7] A method for producing a lithium metal complex oxide, comprising a mixing step of mixing the metal complex compound according to any one of [1] to [6] with a lithium compound, and a firing step of firing the resulting mixture at a temperature of 500°C or higher and 1000°C or lower in an oxygen-containing atmosphere.

[0026] [8] A method for producing a metal complex compound, comprising a slurry preparation step of supplying a first raw material element-containing aqueous solution containing Ni and other elements, a second raw material element-containing aqueous solution containing the other elements, and an alkaline aqueous solution to a reaction tank to obtain a co-precipitate-containing slurry, and a separation step of dehydrating and drying the co-precipitate-containing slurry, in the slurry preparation step, the first raw material element-containing aqueous solution and the second raw material element-containing aqueous solution are supplied from different supply ports, respectively, under a condition that the total flow rate of the first raw material element-containing aqueous solution becomes the largest, the total concentration of the other elements in the first raw material element-containing aqueous solution is set to S1 (unit: g / L), and the total concentration of the other elements in the second raw material element-containing aqueous solution is set to S2 (unit: g / L), and when the ratio of S2 to S1, i.e., S2 / S1, satisfies 0.8 < S2 / S1 ≤ 2 10.0.

[0027] [9] A method for producing a metal complex compound, comprising a slurry preparation step of supplying a first raw material element-containing aqueous solution containing Ni and other elements, a second raw material element-containing aqueous solution containing the other elements, and an alkaline aqueous solution to a reaction tank to obtain a co-precipitate-containing slurry, and a separation step of dehydrating and drying the co-precipitate-containing slurry, in the slurry preparation step, the first raw material element-containing aqueous solution and the second raw material element-containing aqueous solution are supplied from different supply ports, respectively, under a condition that the total flow rate of the first raw material element-containing aqueous solution becomes the largest, the total concentration of the other elements in the first raw material element-containing aqueous solution is set to S1 (unit: g / L), and the total concentration of the other elements in the second raw material element-containing aqueous solution is set to S2 (unit: g / L), and when the ratio of S2 to S1, i.e., S2 / S1, satisfies 0.8 < S2 / S1 ≤ 4 00.0.

[0028]

[10] The production method of the metal composite compound according to [8] or [9], wherein, in the slurry preparation step, when the total number of the supply ports for supplying the first raw element-containing aqueous solution in the reaction tank is set to Nl and the total number of the supply ports for supplying the raw element-containing aqueous solution other than the first raw element-containing aqueous solution is set to N2, Nl / N2≥1.0 is satisfied.

[0029]

[11] The production method of the metal composite compound according to any one of [8] to

[10] , wherein, in the slurry preparation step, the flow rate of the liquid raw material supplied to the reaction tank is adjusted under the condition that the residence time of the coprecipitate in the slurry containing the coprecipitate in the reaction tank is 10.5 hours or less.

[0030] Effects of the Invention

[0031] According to the present application, it is possible to provide a metal composite compound which becomes a raw material of a positive active material of a lithium secondary battery having high initial efficiency, a production method of a lithium metal composite oxide using the same, and a production method of a metal composite compound. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 is a schematic configuration diagram showing one example of a lithium secondary battery.

[0033] Figure 2 is a schematic diagram showing the overall configuration of a full solid-state lithium secondary battery. DETAILED DESCRIPTION

[0034] In the present specification, "high initial efficiency" means that the value of the initial efficiency determined by the following method is 85% or more.

[0035] In the present specification, the metal composite compound (Metal Composite Compound) will be referred to as "MCC" hereinafter.

[0036] The lithium metal composite oxide (Lithium Metal composite Oxide) will be referred to as "LiMO" hereinafter.

[0037] The cathode active material for lithium secondary batteries (Cathode Active Material for lithium secondary batteries) will be referred to as "CAM" hereinafter.

[0038] The expression "Ni" means Ni element unless otherwise specified, and the same applies to the expressions of other elements such as Co and Mn.

[0039] The first efficiency of the lithium secondary battery was calculated by producing the lithium secondary battery in the following manner.

[0040] <Production of lithium metal complex oxide>

[0041] MCC and lithium hydroxide monohydrate powder were weighed in a molar ratio of Li / (Ni+Co+M) = 1.02 and mixed to obtain a mixture. The obtained mixture was fired at 740°C for 5 hours under an oxygen-containing atmosphere to obtain LiMO.

[0042] <Production of positive electrode for lithium secondary battery>

[0043] A paste-like positive electrode mixture was prepared by adding and kneading the CAM containing LiMO produced by the above-described method, a conductive material (acetylene black), and a binder (PVdF) in a ratio to become CAM: conductive material: binder = 92:5:3 (mass ratio). At the time of production of the positive electrode mixture, N-methyl-2-pyrrolidone was used as an organic solvent.

[0044] The obtained positive electrode mixture was coated on an Al foil having a thickness of 40 μm as a current collector and vacuum-dried at 150°C for 8 hours to obtain a positive electrode for a lithium secondary battery. The electrode area of the positive electrode for a lithium secondary battery was set to 1.65 cm 2 .

[0045] <Production of lithium secondary battery>

[0046] The following operations were performed in a glove box under an argon atmosphere.

[0047] The positive electrode for a lithium secondary battery produced in the <Production of positive electrode for lithium secondary battery> was placed on the lower cap of a member for a coin-type battery R2032 (for example, manufactured by Hokuriki Co., Ltd.) with the aluminum foil facing downward, and a separator (porous polyethylene film) was placed thereon. 300 μl of an electrolyte solution was injected thereinto. The electrolyte solution was a solution obtained by dissolving LiPF6 in a mixture of ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate at a ratio of 30:35:35 (volume ratio) to become 1.0 mol / l.

[0048] Next, using a metal lithium as a negative electrode, the above-described negative electrode was placed on the upper side of the separator, a gasket was placed on the upper cap, and caulking was performed with a caulking machine to produce a lithium secondary battery (coin-type half cell R2032).

[0049] <Charge / discharge test>

[0050] The first efficiency test was performed by the following method using the lithium secondary battery produced by the above-described method to calculate the first efficiency of the lithium secondary battery.

[0051] (Measurement method)

[0052] First, the lithium secondary battery produced as described above is left to stand at room temperature for 12 hours, whereby the electrolyte solution is sufficiently impregnated in the separator and the positive electrode mixture layer.

[0053] Next, at a test temperature of 25°C, the current set value is set to 0.2 CA for both charging and discharging, and constant current constant voltage charging and constant current discharging are performed, respectively. The maximum voltage for charging is set to 4.3 V, and the minimum voltage for discharging is set to 2.5 V. The charge capacity is measured, and the obtained value is set as the "first charge capacity" (mAh / g). Further, the discharge capacity is measured, and the obtained value is set as the "first discharge capacity" (mAh / g).

[0054] Then, the first efficiency is calculated by the following equation using the value of the first discharge capacity and the value of the first charge capacity.

[0055] First efficiency (%) = first discharge capacity (mAh / g) / first charge capacity (mAh / g) x 100

[0056] <metal composite compound>

[0057] The MCC of the present embodiment preferably contains at least Ni.

[0058] If the MCC is mixed with a lithium compound and fired, LiMO can be produced.

[0059] In one aspect of the present embodiment, the MCC is composed of primary particles and agglomerates of the primary particles, i.e., secondary particles.

[0060] In one aspect of the present embodiment, the MCC is a powder.

[0061] As the MCC, an oxide or hydroxide containing Ni, or an oxide or hydroxide containing Ni and one or more elements selected from the group consisting of Co and an element M can be exemplified. As the element M, one or more elements selected from the group consisting of Mn, Fe, Cu, Ti, Mg, Al, Zn, Sn, Zr, Nb, Ga, W, Mo, B and Si can be exemplified.

[0062] Relative standard deviation of crystallite diameter distribution of metal composite compound

[0063] The above relative standard deviation is obtained by the following method.

[0064] First, for the powdered MCC, powder X-ray diffraction measurement was performed with CuKa as the radiation source and the measurement range of the diffraction angle 2θ set to 10° or more and 90° or less, and a diffraction peak in the range of 2θ = 19 ± 1° was obtained. As the X-ray diffractometer used in the powder X-ray diffraction measurement, for example, Ultima IV manufactured by Rigaku Corporation can be cited.

[0065] The obtained diffraction peak was analyzed using an analysis software, and the relative standard deviation of the volume-based crystallite diameter distribution was obtained.

[0066] As the above analysis software, for example, the comprehensive powder X-ray analysis software PDXL2 manufactured by Rigaku Corporation can be used.

[0067] The above relative standard deviation is preferably 0.60 or more, more preferably 0.70 or more.

[0068] From the viewpoint of improving the initial efficiency of the lithium secondary battery, the crystallization of LiMO used in the CAM is preferably sufficiently grown. Such a CAM has an increase in the phase having lithium ion conductivity, and the initial efficiency of the lithium secondary battery can be improved.

[0069] The MCC having the above relative standard deviation of the above lower limit value or more means that the range of the crystallite diameter distribution is wide. If such a MCC is mixed with a lithium compound and fired, the MCC and the lithium compound react, and in the process of generating LiMO, the particles of the MCC having a large crystallite diameter preferentially sinter, and grow while incorporating the particles of the MCC having a small crystallite diameter, and thus the crystallization of LiMO easily grows.

[0070] The above relative standard deviation is preferably 1.50 or less, more preferably 1.40 or less, and further preferably 1.30 or less.

[0071] The above upper limit value and the lower limit value of the above relative standard deviation can be arbitrarily combined.

[0072] As examples of the combination, 0.50 or more and 1.50 or less, 0.60 or more and 1.40 or less, and 0.70 or more and 1.30 or less can be cited.

[0073] Mode of the Crystallite Diameter Distribution of the Metal Complex Compound

[0074] The above mode is obtained by analyzing the crystallite diameter distribution obtained by the above method using the above analysis software.

[0075] The above mode is preferably More preferably, the above mode is or more.

[0076] The mode is preferably More preferably, the mode is Further preferably, the mode is The mode is

[0077] The upper limit value and the lower limit value of the mode can be combined arbitrarily.

[0078] As an example of the combination, the following can be given The upper limit value and the lower limit value of the mode are The upper limit value and the lower limit value of the mode are The upper limit value and the lower limit value of the mode are The upper limit value and the lower limit value of the mode are The upper limit value and the lower limit value of the mode are The upper limit value and the lower limit value of the mode are

[0079] The mode being the MCC in the above range means that the MCC has a wide distribution of the crystallite diameters and has a large crystallite diameter, that is, the proportion of the MCC that easily reacts with a lithium compound is high. If such a MCC is used, the crystallization of LiMO can be made to grow sufficiently. The proportion of the phase having the lithium ion conductivity in the CAM containing such a LiMO increases, and the initial efficiency of the lithium secondary battery can be improved.

[0080] "Average Crystallite Diameter in the Distribution of Crystallite Diameters of a Metal Complex"

[0081] The average crystallite diameter is calculated from the crystallite diameters of the distribution of the crystallite diameters on a volume basis and the proportions of the respective crystallite diameters, which are obtained by the above method. Specifically, the values obtained by multiplying the crystallite diameters by the proportions of the respective crystallite diameters are calculated from the distribution of the crystallite diameters, and the sum of the values is taken as the average crystallite diameter.

[0082] The average crystallite diameter is preferably More preferably, the average crystallite diameter is Further preferably, the average crystallite diameter is The average crystallite diameter is

[0083] The average crystallite diameter is preferably More preferably, the average crystallite diameter is Further preferably, the average crystallite diameter is The average crystallite diameter is

[0084] The upper limit value and the lower limit value of the average crystallite diameter can be combined arbitrarily.

[0085] As an example of the combination of the upper limit value and the lower limit value, the following can be given The upper limit value and the lower limit value of the average crystallite diameter are The upper limit value and the lower limit value of the average crystallite diameter are The upper limit value and the lower limit value of the average crystallite diameter are The upper limit value and the lower limit value of the average crystallite diameter are The upper limit value and the lower limit value of the average crystallite diameter are The upper limit value and the lower limit value of the average crystallite diameter are

[0086] The MCC in which the average crystallite diameter is in the above range has a wide range of crystallite diameter distribution and has a high proportion of MCCs having a large crystallite diameter, i.e., which easily reacts with a lithium compound. If such MCCs are used, the particles of LiMO can be sufficiently grown. The phase having lithium ion conductivity in the CAM containing such LiMO increases, and the initial efficiency of the lithium secondary battery can be improved.

[0087] Mode / average crystallite diameter

[0088] The mode / average crystallite diameter of the MCC is preferably 0.55 or less, more preferably 0.54 or less, and further preferably 0.53 or less. In addition, the mode / average crystallite diameter of the MCC can be 0.57 or less, and can be 0.56 or less.

[0089] The mode / average crystallite diameter is the ratio of the above mode to the above average crystallite diameter.

[0090] The mode / average crystallite diameter is preferably 0.10 or more, more preferably 0.15 or more, and further preferably 0.20 or more.

[0091] The above upper limit value and lower limit value of the mode / average crystallite diameter can be combined arbitrarily.

[0092] As examples of the combination, 0.10 or more and 0.55 or less, 0.15 or more and 0.54 or less, and 0.20 or more and 0.53 or less can be given. In addition, as examples of the combination, 0.10 or more and 0.57 or less, and 0.15 or more and 0.56 or less can be given.

[0093] The MCC in which the mode / average crystallite diameter is in the above range has a wide range of crystallite diameter distribution on the side of a large crystallite diameter. In this case, the proportion of MCCs having a large crystallite diameter, i.e., which easily reacts with a lithium compound, is high. If such MCCs are used, the particles of LiMO can be sufficiently grown. The phase having lithium ion conductivity in the CAM containing such LiMO increases, and the initial efficiency of the lithium secondary battery can be improved.

[0094] d90-d10

[0095] The MCC preferably satisfies the following formula (A).

[0096]

[0097] Method for measuring d90 and d10

[0098] In formula (A), d10 and d90 are found by the following method.

[0099] First, the volume-based crystallite diameter distribution of the MCC is obtained by the above-described method. Next, a crystallite diameter distribution function curve is prepared with the volume-based crystallite diameter obtained as the horizontal axis and the probability density function of the crystallite with respect to the crystallite diameter as the vertical axis.

[0100] In the obtained crystallite diameter distribution function curve, the crystallite diameter at the area ratio of 10% from the small diameter side with respect to the total area of the region surrounded by the crystallite diameter distribution function curve and the horizontal axis is set as d10. Further, the crystallite diameter at the area ratio of 90% from the small diameter side with respect to the total area is set as d90.

[0101] The d90 - d10 of the MCC is more preferably The above, further preferably The above.

[0102] The d90 - d10 of the MCC is preferably The above, more preferably The above, further preferably The above.

[0103] The above upper limit value and lower limit value of d90 - d10 can be combined arbitrarily.

[0104] As examples of the combination of the upper limit value and lower limit value, the following can be listed The above and The above, The above and The above, The above and The above.

[0105] If the d90 - d10 of the MCC is in the above range, it means that the particles having a wide range of crystallite diameter distribution and a small crystallite diameter exist to a certain extent or more. Such a MCC is easily taken into the particles of the MCC having a large crystallite diameter when reacting with a lithium compound. As a result, the crystallization of LiMO becomes easy to grow.

[0106] <Composition Formula>

[0107] The MCC is preferably a compound represented by the following <Composition Formula> (I).

[0108] Ni 1-x-y Co x M y O z (OH) 2-α <Composition Formula> (I)

[0109] (Composition formula (I) satisfies 0≤x≤0.5, 0≤y≤0.5, 0≤x+y<1, 0≤z≤3, -0.5≤α≤2, and α-z<2, and M is one or more elements selected from the group consisting of Mn, Fe, Cu, Ti, Mg, Al, Zn, Sn, Zr, Nb, Ga, W, Mo, B, and Si.)

[0110] MCC is preferably a hydroxide represented by the following composition formula (I)-1.

[0111] Ni 1-x-y Co x M y (OH) 2-α Formula (I)-1

[0112] (In composition formula (I)-1, 0≤x≤0.5, 0≤y≤0.5, 0≤x+y<1, and -0.5≤α<2 are satisfied, and M is one or more elements selected from the group consisting of Mn, Fe, Cu, Ti, Mg, Al, Zn, Sn, Zr, Nb, Ga, W, Mo, B, and Si.)

[0113] (x)

[0114] x is preferably 0.01 or more, more preferably 0.02 or more, and particularly preferably 0.03 or more.

[0115] Further, x is preferably 0.44 or less, more preferably 0.42 or less, and particularly preferably 0.40 or less.

[0116] The above upper and lower limit values of x can be combined arbitrarily.

[0117] The above composition formula (I) or the above composition formula (I)-1 preferably satisfies 0.01≤x≤0.44, more preferably 0.02≤x≤0.42, and particularly preferably 0.03≤x≤0.40.

[0118] (y)

[0119] y is preferably 0.01 or more, more preferably 0.02 or more, and particularly preferably 0.03 or more.

[0120] Further, y is preferably 0.44 or less, more preferably 0.42 or less, and particularly preferably 0.40 or less.

[0121] The above upper and lower limit values of y can be combined arbitrarily.

[0122] The above composition formula (I) or the above composition formula (I)-1 preferably satisfies 0.01≤y≤0.44, more preferably 0.02≤y≤0.42, and particularly preferably 0.03≤y≤0.40.

[0123] (z)

[0124] z is preferably 0.02 or more, more preferably 0.03 or more, and particularly preferably 0.05 or more.

[0125] z is preferably 2.8 or less, more preferably 2.6 or less, and particularly preferably 2.4 or less.

[0126] The upper limit value and the lower limit value can be combined arbitrarily.

[0127] The composition formula (I) preferably satisfies 0 ≤ z ≤ 2.8, more preferably 0.02 ≤ z ≤ 2.8, further preferably 0.03 ≤ z ≤ 2.6, and particularly preferably 0.05 ≤ z ≤ 2.4.

[0128] (α)

[0129] α is preferably -0.45 or more, more preferably -0.40 or more, and particularly preferably -0.35 or more.

[0130] α is preferably 1.8 or less, more preferably 1.6 or less, and particularly preferably 1.4 or less. The upper limit value and the lower limit value can be combined arbitrarily.

[0131] The composition formula (I) or the composition formula (I)-1 preferably satisfies -0.45 ≤ α ≤ 1.8, more preferably -0.40 ≤ α ≤ 1.6, and particularly preferably -0.35 ≤ α ≤ 1.4.

[0132] In the present embodiment, the composition formula (I) or the composition formula (I)-1 preferably satisfies 0.01 ≤ x ≤ 0.44, 0.01 ≤ y ≤ 0.44, 0 ≤ z ≤ 2.8, and -0.45 ≤ α ≤ 1.8.

[0133] Composition analysis of MCC

[0134] The composition analysis of the MCC can be performed by dissolving the obtained MCC powder in hydrochloric acid and then measuring using an ICP emission spectrometry device.

[0135] As the ICP emission spectrometry device, for example, Optima 8300 manufactured by PerkinElmer Corporation can be used.

[0136] Examples of the MCC described below are preferably used.

[0137] • (Example 1) The relative standard deviation of the MCC described above is 0.50 or more, and the mode described above is or more.

[0138] • (Example 2) The relative standard deviation of the MCC described above is 0.50 or more, and the mode described above is The above, and satisfies the composition formula (I).

[0139] • (Example 3) The above relative standard deviation of the MCC is 0.50 or more, and the above average crystallite diameter is or more.

[0140] • (Example 4) The above relative standard deviation of the MCC is 0.50 or more, and the above average crystallite diameter is The above, and satisfies the composition formula (I).

[0141] The MCC of the above (Example 1) to (Example 4) is likely to have a crystallite diameter distribution that is wide in the range of large crystallite diameters. In this case, the proportion of MCC that has a large crystallite diameter, that is, that is likely to react with a lithium compound, is high. If the MCC of the above (Example 1) to (Example 4) is used, the particles of LiMO can be made to grow sufficiently. A CAM that contains such LiMO can improve the initial efficiency of a lithium secondary battery.

[0142] <Manufacturing method 1 of metal complex compound>

[0143] The manufacturing method of the MCC of the present embodiment successively has a slurry preparation step and a separation step.

[0144] The slurry preparation step is a step of obtaining a co-precipitate-containing slurry by supplying a first raw element-containing aqueous solution containing Ni and other elements, a second raw element-containing aqueous solution containing other elements, and an alkaline aqueous solution to a reaction tank.

[0145] The other elements refer to elements other than Ni, and examples include one or more elements selected from the group consisting of Co and an element M. The element M is one or more elements selected from the group consisting of Mn, Fe, Cu, Ti, Mg, Al, Zn, Sn, Zr, Nb, Ga, W, Mo, B, and Si.

[0146] The separation step is a step of separating the MCC by dehydrating and drying the co-precipitate-containing slurry obtained in the slurry preparation step.

[0147] [Slurry preparation step]

[0148] In the slurry preparation step, the first raw element-containing aqueous solution and the second raw element-containing aqueous solution are supplied separately to the inside of the reaction tank from different supply ports. At this time, the first raw element-containing aqueous solution and the second raw element-containing aqueous solution are supplied under the condition that the total flow rate of the first raw element-containing aqueous solution becomes the largest among the raw element-containing aqueous solutions supplied to the reaction tank.

[0149] In other words, among the raw element-containing aqueous solutions supplied to the reaction tank, the raw element-containing aqueous solution having the largest total flow rate is set as the first raw element-containing aqueous solution. The second raw element-containing aqueous solution is a raw element-containing aqueous solution having a flow rate smaller than that of the first raw element-containing aqueous solution.

[0150] The first raw element-containing aqueous solution and the second raw element-containing aqueous solution can contain the same elements or different elements.

[0151] The same raw element-containing aqueous solution can also be supplied from multiple supply ports to the inside of the reaction tank by branching the pipe. In this case, the total value of the flow rates of the raw element-containing aqueous solution supplied from each of the supply ports is set as the total flow rate of the raw element-containing aqueous solution.

[0152] For example, in the case where the second raw element-containing aqueous solution is supplied to the reaction tank from two supply ports (supply port 1 and supply port 2), the total amount of the flow rate of the second raw element-containing aqueous solution in supply port 1 and the flow rate of the second raw element-containing aqueous solution in supply port 2 becomes the total flow rate of the second raw element-containing aqueous solution. The same applies to the first raw element-containing aqueous solution.

[0153] In the slurry preparation step, when the total flow rates of the respective raw element-containing aqueous solutions are compared, the respective raw element-containing aqueous solutions are supplied under the condition that the total flow rate of the first raw element-containing aqueous solution becomes the largest. By including Ni and other elements in the first raw element-containing aqueous solution whose total flow rate becomes the largest, the speed of nucleus generation becomes slow, the speed of nucleus generation of the co-precipitate easily varies, and the speed of growth of the crystallite diameter easily varies. If this condition is met, the range of the crystallite distribution of the manufactured MCC easily becomes wide, and an MCC in which the relative standard deviation of the crystallite diameter distribution, the mode, the average crystallite diameter, and d90-d10 are within the ranges of the present embodiment can be obtained.

[0154] When the total concentration of the other elements of the first raw element-containing aqueous solution is set as S1 (unit: g / L) and the total concentration of the other elements of the second raw element-containing aqueous solution is set as S2 (unit: g / L), the ratio of S2 to S1, that is, S2 / S1 satisfies 0.8 < S2 / S1 ≤ 2 10.0.

[0155] S2 / S1 is preferably 1.0 or more, more preferably 1.5 or more. S2 / S1 is preferably 100.0 or less, more preferably 25.0 or less, and particularly preferably 6.0 or less. The above upper and lower limits can be combined arbitrarily.

[0156] S2 / S1 preferably satisfies 1.0 ≤ S2 / S1 ≤ 100.0, more preferably 1.0 ≤ S2 / S1 ≤ 25.0, and particularly preferably 1.5 ≤ S2 / S1 ≤ 6.0.

[0157] Further, in the slurry preparation step, a plurality of kinds of raw material element-containing aqueous solutions other than the first and second raw material element-containing aqueous solutions can be used.

[0158] In the case where a plurality of kinds of raw material element-containing aqueous solutions are used, in each of the raw material element-containing aqueous solutions, the ratio of the total concentration of the other elements in the raw material element-containing aqueous solution to the total concentration of the other elements in the first raw material element-containing aqueous solution is preferably more than 0.8 and 210.0 or less.

[0159] For example, in the case where a third and a fourth raw material element-containing aqueous solution are used in addition to the first and second raw material element-containing aqueous solutions as the raw material element-containing aqueous solution supplied to the reaction tank, the total concentration of the other elements in the third raw material element-containing aqueous solution is set to S3 (unit: g / L), and the total concentration of the other elements in the fourth raw material element-containing aqueous solution is set to S4 (unit: g / L). In this case, in addition to the value of S2 / S1 described above, the values of S3 / S1 and S4 / S1 are preferably more than 0.8 and 210.0 or less.

[0160] One example of the total concentration of the other elements contained in the first raw material element-containing aqueous solution is more than 0 g / L and 100.0 g / L or less.

[0161] One example of the total concentration of the other elements contained in the second, third, or fourth raw material element-containing aqueous solution is 0.5 g / L or more and 300.0 g / L or less.

[0162] If the raw material element-containing aqueous solution having S2 / S1 in the above-described range is supplied, the speed of generation of the nuclei of the coprecipitate can be made to differ between the region where the second raw material element-containing aqueous solution is dropped and the region where the first raw material element-containing aqueous solution is dropped. Specifically, the nuclei of the coprecipitate are generated faster in the region where the second raw material element-containing aqueous solution is dropped than in the region where the first raw material element-containing aqueous solution is dropped.

[0163] If the generated nuclei are further supplied with the metal raw material, the growth of the crystallites progresses. When the growth of the crystallites proceeds, the growth speed of the crystallite diameter becomes likely to differ depending on the speed of generation of the nuclei. If this condition is met, the range of the distribution of the crystallites of the manufactured MCC is likely to become wide, and the MCC in which the relative standard deviation of the crystallite diameter distribution, the mode, the average crystallite diameter, and d90-d10 are within the range of the present embodiment can be obtained.

[0164] Further, in the slurry adjustment step, it is preferable that N1 / N2≥1.0 be satisfied.

[0165] Here, N1 is the total number of supply ports (unit: sites) for supplying the above-mentioned first raw element-containing aqueous solution to the reaction tank, and N2 is the total number of supply ports (unit: sites) for supplying a raw element-containing aqueous solution other than the above-mentioned first raw element-containing aqueous solution. The raw element-containing aqueous solution other than the first raw element-containing aqueous solution refers to, for example, a second raw element-containing aqueous solution, a third raw element-containing aqueous solution, a fourth raw element-containing aqueous solution, and the like.

[0166] For example, in the case where the first raw element-containing aqueous solution is supplied from four supply ports to the reaction tank, N1 is four sites, and in the case where the second raw element-containing aqueous solution is supplied from two supply ports and the third raw element-containing aqueous solution is supplied from three supply ports to the reaction tank, N2 is five sites.

[0167] More preferably, N1 / N2 is equal to or greater than 1.5, further preferably N1 / N2 is equal to or greater than 2.0, and particularly preferably N1 / N2 is equal to or greater than 2.5.

[0168] In the case where N1 / N2 is less than 1.0, the first raw element-containing aqueous solution is not easily dispersed when the first raw element-containing aqueous solution is supplied to the reaction tank, and it becomes difficult to obtain MCC having the desired crystallinity.

[0169] In the slurry preparation step, the flow rate of the liquid raw material supplied to the above-mentioned reaction tank is preferably adjusted under the condition that the residence time of the coprecipitate in the slurry in the reaction tank is 10.5 hours or less.

[0170] Here, the liquid raw material is each aqueous solution supplied to the reaction tank, and refers to, for example, the first raw element-containing aqueous solution, the second raw element-containing aqueous solution, the alkaline aqueous solution, the complexing agent, and the like.

[0171] More preferably, the above-mentioned residence time is 10.0 hours or less, and further preferably 9.0 hours or less.

[0172] Here, the residence time refers to the average time until the nucleus of the coprecipitate generated at a certain time is retained in the reaction tank together with the coprecipitate-containing slurry in the reaction tank by the newly supplied liquid raw material to the reaction tank and is discharged out of the reaction tank system. Specifically, it is a value calculated by the following formula. Residence time (time) = volume of the reaction tank (L) / total flow rate of the supplied liquid raw material (L / h)

[0173] If the residence time is the above-mentioned upper limit value or less, the amount of MCC obtained per unit time is large, and the production efficiency easily becomes high.

[0174] The residence time is preferably 2.0 hours or more, more preferably 3.0 hours or more, and more preferably 4.0 hours or more.

[0175] The residence time can be, for example, 2.0 hours or more and 10.5 hours or less, 2.0 hours or more and 10.0 hours or less, 3.0 hours or more and 9.0 hours or less, or 4.0 hours or more and 9.0 hours or less.

[0176] In the case where the residence time exceeds the lower limit value, the generated MCC can sufficiently grow, and the desired crystallinity can be easily satisfied.

[0177] Other conditions for the preparation method in the slurry preparation step will be described in detail below using, as an example, a metal complex hydroxide containing Ni, Co, and Al.

[0178] The slurry preparation step can be performed by a known batch coprecipitation method or a continuous coprecipitation method.

[0179] Specifically, a nickel salt solution, a cobalt salt solution, an aluminum salt solution, and a complexing agent, which are aqueous solutions containing raw material elements, are reacted by the continuous coprecipitation method described in JP-A-2002-201028 to produce a Ni (1-x-y) Co x Al y hydroxide represented by the formula: NiCoAl(OH)2(OH)2 (in the formula, 0 < x ≤ 0.5, 0 < y ≤ 0.5, and 0 ≤ x + y < 1).

[0180] The solute, i.e., the nickel salt, of the above-mentioned nickel salt solution is not particularly limited, but at least one of nickel sulfate, nickel nitrate, nickel chloride, and nickel acetate, for example, can be used.

[0181] The solute, i.e., the cobalt salt, of the above-mentioned cobalt salt solution can be, for example, at least one of cobalt sulfate, cobalt nitrate, cobalt chloride, and cobalt acetate.

[0182] The solute, i.e., the aluminum salt, of the above-mentioned aluminum salt solution can be, for example, at least one of aluminum sulfate, aluminum nitrate, and aluminum chloride.

[0183] The above-mentioned aqueous solution containing raw material elements is used in a proportion corresponding to the composition ratio of the above-mentioned Ni (1-x-y) Co x Al y (OH)2. That is, the amount of each metal salt is defined in a proportion corresponding to the molar ratio of Ni, Co, and Al resulting from the mixing of the above-mentioned aqueous solution containing raw material elements to the proportion of (1-x-y):x:y of the composition formula (I) of the MCC. In addition, water is used as the solvent.

[0184] As the complexing agent, a substance capable of forming a complex with nickel ions, cobalt ions, and aluminum ions in an aqueous solution, such as an ammonium ion donor, hydrazine, ethylenediaminetetraacetic acid, nitrilotriacetic acid, and uracil diacetic acid, and glycine, for example, can be used. The ammonium ion donor is, for example, ammonium hydroxide, ammonium sulfate, ammonium chloride, ammonium carbonate, or ammonium fluoride.

[0185] In the manufacturing process of the MCC, the amount of the complexing agent contained in the mixed solution containing a nickel salt solution, a cobalt salt solution, an aluminum salt solution, and a complexing agent is, for example, greater than 0 and 2.0 or less, in terms of a molar ratio with respect to the total number of moles of the metal salts (the nickel salt, the cobalt salt, and the aluminum salt).

[0186] In the coprecipitation method, in order to adjust the pH of the mixed solution containing a nickel salt solution, a cobalt salt solution, an aluminum salt solution, and a complexing agent, an alkali metal hydroxide is added to the mixed solution before the pH of the mixed solution changes from alkaline to neutral. The alkali metal hydroxide is, for example, sodium hydroxide or potassium hydroxide.

[0187] In the coprecipitation method, a continuous reaction tank is preferably used. The MCC obtained by the continuous coprecipitation method contains both fine particles and coarse particles, and the distribution of the crystallite diameter of the MCC easily becomes large.

[0188] The reaction tank used in the continuous coprecipitation method can use a reaction tank of a type in which the reaction precipitate formed is overflowed in order to separate the reaction precipitate.

[0189] Further, in the reaction, the pH in the reaction tank is controlled, for example, in a range of 9 or higher and 13 or lower. If the pH is in the above range, the crystal of the obtained MCC easily grows, and the MCC in which the mode, the average crystallite diameter, and d90-d10 of the distribution of the crystallite diameter are in the range of the present embodiment can be obtained.

[0190] Note that the value of the pH in the present specification is defined as a value measured at a temperature of 40°C of a solution to be measured. The pH of the solution to be measured is measured when the temperature of the solution sampled from the reaction tank reaches 40°C.

[0191] In the case where the temperature of the sampled solution is lower than 40°C, the pH is measured when the solution is heated to reach 40°C.

[0192] In the case where the temperature of the sampled solution is higher than 40°C, the pH is measured when the solution is cooled to reach 40°C.

[0193] In the reaction, the temperature of the solution in the reaction tank is controlled, for example, in a range of 20°C or higher and 80°C or lower, preferably in a range of 30°C or higher and 75°C or lower.

[0194] By the slurry preparation process, a coprecipitate-containing slurry is obtained.

[0195] [Separation Process]

[0196] After the above reaction, the MCC is obtained by dehydrating and drying the slurry containing the co-precipitate. In the above example, a nickel-cobalt-aluminum metal composite hydroxide is obtained as the MCC. In addition, in the case where impurities derived from the aqueous solution containing the raw material elements remain when the co-precipitate is washed with water, the co-precipitate can be washed with weak acid water or an alkaline solution containing sodium hydroxide or potassium hydroxide as needed.

[0197] Note that, in the above example, a nickel-cobalt-aluminum metal composite hydroxide is produced as the MCC, but a nickel-cobalt-aluminum metal composite oxide can also be produced.

[0198] For example, a nickel-cobalt-aluminum metal composite oxide can be produced by oxidizing the nickel-cobalt-aluminum metal composite hydroxide. The total time from the start of temperature increase to the end of temperature maintenance at the maximum temperature is preferably set to 1 hour or more and 30 hours or less. The maximum temperature is preferably 350°C or more and 800°C or less, more preferably 400°C or more and 700°C or less.

[0199] The maximum temperature in the present specification refers to the maximum temperature of the temperature maintained in the atmosphere of the firing furnace in the firing process, and is the firing temperature in the firing process. In the case of a formal firing process having a plurality of heating processes, the maximum temperature refers to the maximum temperature in each heating process.

[0200] The temperature increase rate in the present specification is calculated from the time from the start of temperature increase to the time at which the maximum temperature is reached in the firing device and the temperature difference from the temperature at the start of temperature increase to the maximum temperature in the atmosphere of the firing furnace of the firing device.

[0201] <Method 2 for producing a metal composite compound>

[0202] The method 2 for producing a metal composite compound is the same as the above <Method 1 for producing a metal composite compound> except that S2 / S1 satisfies 0.8 < S2 / S1 ≤ 400.0.

[0203] In the method 2 for producing a metal composite compound, S2 / S1 is preferably 1.0 or more, more preferably 1.5 or more. S2 / S1 is preferably 390.0 or less, more preferably 385.0 or less, and particularly preferably 380.0 or less. The above upper and lower limits can be combined arbitrarily.

[0204] S2 / S1 preferably satisfies 1.0 ≤ S2 / S1 ≤ 390.0, more preferably 1.0 ≤ S2 / S1 ≤ 385.0, and particularly preferably 1.5 ≤ S2 / S1 ≤ 380.0.

[0205] If S2 / S1 is within the above range, particularly below the above upper limit, then when compared with the same composition, it is easy to obtain MCC having a wide distribution of crystallite diameters on the side having a larger average crystallite diameter.

[0206] <Method for producing lithium metal complex oxide>

[0207] The method for producing LiMO of the present embodiment has a mixing step of mixing the MCC with a lithium compound, and a firing step of firing the obtained mixture in an oxygen-containing atmosphere at a temperature of 500°C or higher and 1000°C or lower.

[0208] In the method for producing LiMO, the above-described MCC of the present embodiment is used. The MCC is produced by the method described in the above <Method for producing metal complex compound>.

[0209] [The mixing step]

[0210] The MCC is mixed with a lithium compound.

[0211] As the lithium compound, one or more selected from the group consisting of lithium carbonate, lithium hydroxide, and lithium hydroxide monohydrate can be used.

[0212] The lithium compound and the MCC are mixed in consideration of the composition ratio of the final target object, and a mixture of the lithium compound and the MCC is obtained.

[0213] [The firing step]

[0214] The obtained mixture is fired in an oxygen-containing atmosphere at a firing temperature of 500°C or higher and 1000°C or lower. By firing the mixture, the crystallization of LiMO is grown.

[0215] The firing temperature in the present specification refers to the temperature of the atmosphere in the firing furnace, and the maximum temperature of the holding temperature (maximum holding temperature).

[0216] In the case where the firing step has a plurality of heating steps, the firing temperature refers to the temperature at the time of heating at the maximum holding temperature in each heating step.

[0217] As the holding temperature, specifically, 550°C or higher and 980°C or lower, and preferably 600°C or higher and 960°C or lower are preferable.

[0218] Further, the time of holding at the above-described holding temperature can be exemplified by 0.1 hours or more and 20 hours or less, and preferably 0.5 hours or more and 10 hours or less.

[0219] Further, it is preferable to perform the firing in an oxygen-containing atmosphere. Specifically, it is preferable to introduce oxygen gas and set the inside of the firing furnace to an oxygen-containing atmosphere.

[0220] The temperature increase rate is calculated from the time from the start of temperature increase in the firing device to the time when the highest holding temperature is reached and the temperature difference from the temperature at the start of temperature increase to the highest holding temperature in the firing furnace of the firing device.

[0221] After the firing process, the fired product obtained by firing is appropriately pulverized and sieved to obtain LiMO.

[0222] < Lithium secondary battery >

[0223] Next, the constitution of a preferred lithium secondary battery in the case where LiMO of the present embodiment is used as a CAM is described.

[0224] Further, a preferred positive electrode for a lithium secondary battery in the case where LiMO of the present embodiment is used as a CAM (hereinafter, sometimes referred to as a positive electrode) is described.

[0225] Further, a preferred lithium secondary battery for use as a positive electrode is described.

[0226] One example of a preferred lithium secondary battery in the case where LiMO of the present embodiment is used as a CAM has a positive electrode and a negative electrode, a separator interposed between the positive electrode and the negative electrode, and an electrolyte disposed between the positive electrode and the negative electrode.

[0227] One example of a lithium secondary battery has a positive electrode and a negative electrode, a separator interposed between the positive electrode and the negative electrode, and an electrolyte disposed between the positive electrode and the negative electrode.

[0228] Figure 1 is a schematic view showing one example of a lithium secondary battery. The cylindrical lithium secondary battery 10 of the present embodiment is manufactured as follows.

[0229] First, as shown in Figure 1 the electrode group 4 is made by stacking and winding a pair of separators 1 in a belt shape, a positive electrode 2 in a belt shape having a positive electrode lead 21 at one end, and a negative electrode 3 in a belt shape having a negative electrode lead 31 at one end in the order of the separator 1, the positive electrode 2, the separator 1, and the negative electrode 3.

[0230] Next, after the electrode group 4 and an insulator not shown are accommodated in the battery can 5, the bottom of the can is sealed, the electrolyte 6 is impregnated in the electrode group 4, and the electrolyte is disposed between the positive electrode 2 and the negative electrode 3. Further, by sealing the upper portion of the battery can 5 with a top insulator 7 and a closure 8, the lithium secondary battery 10 can be manufactured.

[0231] As the shape of the electrode group 4, for example, a columnar shape can be cited in which the cross-sectional shape when the electrode group 4 is cut in the vertical direction with respect to the axis of winding is a circle, an ellipse, a rectangle, or a rectangle obtained by rounding the corners.

[0232] Further, as the shape of the lithium secondary battery having such an electrode group 4, a shape prescribed in a standard for batteries prescribed by the International Electrotechnical Commission (IEC), namely, IEC60086 or JIS C 8500 can be adopted. Shapes such as a cylindrical shape or a square shape can be cited as examples.

[0233] Further, the lithium secondary battery is not limited to the above-described wound-type configuration, and can be a stacked-type configuration obtained by repeatedly stacking the positive electrode, the separator, the negative electrode, and the separator. As the lithium secondary battery of the stacked type, a so-called coin-type battery, a button-type battery, or a paper-type (or sheet-type) battery can be cited as examples.

[0234] Hereinafter, each configuration will be described in order.

[0235] (Positive electrode)

[0236] The positive electrode can be manufactured by first preparing a positive electrode mixture containing the CAM, the conductive material, and the binder, and supporting the positive electrode mixture on a positive electrode current collector.

[0237] (Conductive material)

[0238] As the conductive material possessed by the positive electrode, a carbon material can be used. As the carbon material, graphite powder, carbon black (for example, acetylene black), and fibrous carbon material, and the like can be cited as examples.

[0239] The proportion of the conductive material in the positive electrode mixture is preferably 5 to 20 parts by mass with respect to 100 parts by mass of the CAM.

[0240] (Binder)

[0241] As the binder possessed by the positive electrode, a thermoplastic resin can be used. As the thermoplastic resin, a polyimide resin, a polyvinylidene fluoride (hereinafter sometimes referred to as PVdF), a polytetrafluoroethylene, and the like fluororesin; a polyolefin resin such as polyethylene and polypropylene, and the resin described in WO2019 / 098384A1 or US2020 / 0274158A1 can be cited as examples.

[0242] (Positive electrode current collector)

[0243] As the positive electrode current collector possessed by the positive electrode, a strip-shaped member using a metal material such as Al, Ni, or stainless steel as a forming material can be used.

[0244] As the method of supporting the positive electrode mixture on the positive electrode current collector, a method in which the positive electrode mixture is pasted using an organic solvent, the paste of the obtained positive electrode mixture is applied to at least one side of the positive electrode current collector and dried, an electrode pressing process is performed, and cementation is performed can be cited as an example.

[0245] In the case where the positive electrode mixture is pasted, as the organic solvent that can be used, N-methyl-2-pyrrolidone (hereinafter sometimes referred to as NMP) can be exemplified.

[0246] As a method of applying the paste of the positive electrode mixture to the positive electrode current collector, for example, a slit extrusion coating method, a screen coating method, a curtain coating method, a doctor blade coating method, a gravure coating method, and an electrostatic spray method can be exemplified.

[0247] By the above exemplified method, the positive electrode can be manufactured.

[0248] (Negative electrode)

[0249] The negative electrode of the lithium secondary battery can be exemplified as an electrode in which a negative electrode active material is supported on a negative electrode current collector and an electrode in which a negative electrode active material alone is formed, as long as the lithium ion can be doped and dedoped at a lower potential than the positive electrode.

[0250] (Negative electrode active material)

[0251] As the negative electrode active material possessed by the negative electrode, a carbon material, a chalcogenide compound (oxide or sulfide, etc.), a nitride, a metal or an alloy, and a material capable of doping and dedoping the lithium ion at a lower potential than the positive electrode can be exemplified.

[0252] As the carbon material that can be used as the negative electrode active material, graphite such as natural graphite or artificial graphite, coke, carbon black, carbon fiber, and a sintered body of an organic high molecular compound can be exemplified.

[0253] As the oxide that can be used as the negative electrode active material, a silicon oxide represented by SiOx (wherein x is a positive real number), SnO2, and SnO represented by SnOx (wherein x is a positive real number) can be exemplified. x x As the tin oxide, SnO2, and SnO represented by SnOx (wherein x is a positive real number) can be exemplified. 12 and a metal complex oxide containing Li and Ti such as Li4Ti5O12 and LiVO2.

[0254] Further, as the metal that can be used as the negative electrode active material, lithium metal, silicon metal, and tin metal can be exemplified. As the material that can be used as the negative electrode active material, the material described in WO2019 / 098384A1 or US2020 / 0274158A1 can also be used.

[0255] These metals or alloys are mainly used alone as an electrode, for example, after being processed into a foil shape.

[0256] ​Among the above-described negative electrode active materials, a carbon material using graphite such as natural graphite or artificial graphite as a main component is preferably used from the reasons that the potential of the negative electrode does not substantially change from the uncharged state to the fully charged state at the time of charging (the potential flatness is good), the average discharge potential is low, and the capacity retention rate at the time of repeated charging and discharging is high (the cycle characteristics are good). As the shape of the carbon material, any one of, for example, a flake shape like natural graphite, a spherical shape like a mesocarbon microbead, a fibrous shape like a graphitized carbon fiber, or an agglomerate of fine powder can be used.

[0257] The above-described negative electrode mixture can also contain a binder as needed. As the binder, a thermoplastic resin can be used, and specifically, PVdF, a thermoplastic polyimide, carboxymethyl cellulose (hereinafter sometimes referred to as CMC), a styrene butadiene rubber (hereinafter sometimes referred to as SBR), polyethylene, and polypropylene can be used.

[0258] (Negative electrode current collector)

[0259] As the negative electrode current collector possessed by the negative electrode, a belt-shaped member using a metal material such as Cu, Ni, or stainless steel as a forming material can be used.

[0260] As a method of supporting the negative electrode mixture on such a negative electrode current collector, a method using press molding, a method of paste-forming using a solvent or the like and coating on the negative electrode current collector or drying and then pressing and crimping can be used as in the case of the positive electrode.

[0261] (Separator)

[0262] As the separator possessed by the lithium secondary battery, a material having a porous film, a nonwoven fabric, or a woven fabric or the like shape formed of a polyolefin resin such as polyethylene and polypropylene, a fluororesin, or a nitrogen-containing aromatic polymer or the like can be used. Furthermore, two or more of these materials can be used to form the separator, and these materials can be stacked to form the separator. Furthermore, the separator described in JP-A-2000-030686 or US20090111025A1 can be used.

[0263] (Electrolyte solution)

[0264] The electrolyte solution possessed by the lithium secondary battery contains an electrolyte and an organic solvent.

[0265] As the electrolyte contained in the electrolyte solution, a lithium salt such as LiClO4and LiPF6can be used, and a mixture of two or more of these can also be used.

[0266] Furthermore, as the organic solvent contained in the above-described electrolyte solution, a carbonate such as propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate can be used.

[0267] As the organic solvent, it is preferable to use two or more of them in combination. Among them, a mixed solvent containing a carbonate is preferable, and a mixed solvent of a cyclic carbonate and a non-cyclic carbonate and a mixed solvent of a cyclic carbonate and an ether are further preferable.

[0268] Further, as the electrolyte, in order to improve the safety of the obtained lithium secondary battery, it is preferable to use an electrolyte containing a lithium salt containing fluorine such as LiPF6and an organic solvent having a fluorine substituent. As the electrolyte and the organic solvent contained in the electrolyte, the electrolyte and the organic solvent described in WO2019 / 098384A1 or US2020 / 0274158A1 can also be used.

[0269] <All-solid-state lithium secondary battery>

[0270] Next, the constitution of the all-solid-state lithium secondary battery will be described, and a positive electrode using LiMO of one aspect of the present application as the CAM of the all-solid-state lithium secondary battery and an all-solid-state lithium secondary battery having the same will be described.

[0271] Figure 2 is a schematic view showing one example of the all-solid-state lithium secondary battery of the present embodiment. Figure 2 The all-solid-state lithium secondary battery 1000 shown in FIG. 1 has a laminate 100 having a positive electrode 110, a negative electrode 120, and a solid electrolyte layer 130, and an outer packaging body 200 that accommodates the laminate 100. Further, the all-solid-state lithium secondary battery 1000 can also be of a bipolar structure in which a CAM and a negative electrode active material are arranged on both sides of a current collector. As a specific example of the bipolar structure, for example, the structure described in JP-A-2004-95400 can be cited. As for the materials constituting each member, they will be described later.

[0272] The laminate 100 can also have an external terminal 113 connected to the positive electrode current collector 112 and an external terminal 123 connected to the negative electrode current collector 122. Further, the all-solid-state lithium secondary battery 1000 can also have a separator between the positive electrode 110 and the negative electrode 120.

[0273] The all-solid-state lithium secondary battery 1000 further has an insulator not shown that insulates the laminate 100 from the outer packaging body 200 and a seal not shown that seals the opening portion 200a of the outer packaging body 200.

[0274] The outer packaging body 200 can use a container obtained by molding a metal material having high corrosion resistance such as aluminum, stainless steel, or nickel-plated steel. Further, as the outer packaging body 200, a container obtained by processing a laminated film on which corrosion-resistant processing has been performed on at least one face into a bag shape can also be used.

[0275] As the shape of the all-solid-state lithium secondary battery 1000, for example, a coin type, a button type, a paper type (or a sheet type), a cylindrical type, a square type, or a laminate type (a pouch type) or the like can be exemplified.

[0276] For the all-solid-state lithium secondary battery 1000, a configuration having one stack 100 is illustrated as one example, but the present embodiment is not limited thereto. The all-solid-state lithium secondary battery 1000 can also be configured such that the stack 100 is a unit cell, and a plurality of unit cells (stacks 100) are enclosed in the inside of the outer packaging body 200.

[0277] Hereinafter, each configuration will be described in order.

[0278] (Positive electrode)

[0279] The positive electrode 110 has a positive electrode active material layer 111 and a positive electrode current collector 112.

[0280] The positive electrode active material layer 111 contains the LiMO described above as one aspect of the present application and a solid electrolyte. In addition, the positive electrode active material layer 111 can also contain a conductive material and a binder.

[0281] (Solid electrolyte)

[0282] As the solid electrolyte contained in the positive electrode active material layer 111 of the present embodiment, a solid electrolyte known to be used in an all-solid-state lithium secondary battery having lithium ion conductivity can be used. As such a solid electrolyte, an inorganic electrolyte and an organic electrolyte can be exemplified. As the inorganic electrolyte, an oxide-based solid electrolyte, a sulfide-based solid electrolyte, and a hydride-based solid electrolyte can be exemplified. As the organic electrolyte, a polymer-based solid electrolyte can be exemplified. As each electrolyte, the compounds described in WO2020 / 208872A1, US2016 / 0233510A1, US2012 / 0251871A1, US2018 / 0159169A1 can be exemplified, for example, the following compounds can be exemplified.

[0283] (Oxide-based solid electrolyte)

[0284] As the oxide-based solid electrolyte, for example, a perovskite-type oxide, a NASICON-type oxide, a LISICON-type oxide, and a garnet-type oxide, or the like can be exemplified. Specific examples of each oxide can exemplify the compounds described in WO2020 / 208872A1, US2016 / 0233510A1, US2020 / 0259213A1, for example, the following compounds can be exemplified.

[0285] As the perovskite-type oxide, Li a La 1-aLi3La2TiO7 (0 < a < 1) and the like Li-La-Ti-based oxides, Li b La 1-b TaO3 (0 < b < 1) and the like Li-La-Ta-based oxides, and Li c La 1-c NbO3 (0 < c < 1) and the like Li-La-Nb-based oxides, and the like.

[0286] As the NASICON-type oxide, there can be mentioned Li 1+d Al d Ti 2-d (PO4)3 (0 < d < 1) and the like. The NASICON-type oxide is Li m M 1 n M 2 o P p O q (In the formula, M 1 is one or more kinds of elements selected from the group consisting of B, Al, Ga, In, C, Si, Ge, Sn, Sb, and Se. M 2 is one or more kinds of elements selected from the group consisting of Ti, Zr, Ge, In, Ga, Sn, and Al. m, n, o, p, and q are arbitrary positive numbers.)-represented oxides.

[0287] As the LISICON-type oxide, there can be mentioned Li4M 3 O4-Li3M 4 O4 (M 3 is one or more kinds of elements selected from the group consisting of Si, Ge, and Ti. M 4 is one or more kinds of elements selected from the group consisting of P, As, and V.)-represented oxides and the like.

[0288] As the garnet-type oxide, there can be mentioned Li7La3Zr2O 12 (also called LLZ) and the like Li-La-Zr-based oxides and the like.

[0289] The oxide-based solid electrolyte can be a crystalline material or a non-crystalline material.

[0290] (Sulfide-based solid electrolyte)

[0291] As the sulfide-based solid electrolyte, there can be mentioned Li2S-P2S5-based compounds, Li2S-SiS2-based compounds, Li2S-GeS2-based compounds, Li2S-B2S3-based compounds, LiI-Si2S-P2S5-based compounds, LiI-Li2S-P2O5-based compounds, LiI-Li3PO4-P2S5-based compounds, and Li10 GeP2S 12 compounds, etc.

[0292] Note that in the present specification, the expression "a compound of the sulfide-based solid electrolyte" is used as a general term for a solid electrolyte mainly containing the "compound of the sulfide-based solid electrolyte" described above. For example, for a Li2S-P2S5 compound, a solid electrolyte mainly containing Li2S and P2S5, further containing other raw materials is included. The proportion of Li2S included in the Li2S-P2S5 compound is, for example, 50 to 90% by mass with respect to the entire Li2S-P2S5 compound. The proportion of P2S5 included in the Li2S-P2S5 compound is, for example, 10 to 50% by mass with respect to the entire Li2S-P2S5 compound. Further, the proportion of other raw materials included in the Li2S-P2S5 compound is, for example, 0 to 30% by mass with respect to the entire Li2S-P2S5 compound. Further, for the Li2S-P2S5 compound, a solid electrolyte in which the mixing ratio of Li2S to P2S5 is different is also included.

[0293] As the Li2S-P2S5 compound, Li2S-P2S5, Li2S-P2S5-LiI, Li2S-P2S5-LiCl, Li2S-P2S5-LiBr, Li2S-P2S5-LiI-LiBr, Li2S-P2S5-Li2O, Li2S-P2S5-Li2O-LiI, and Li2S-P2S5-ZnS can be exemplified. m S n (m, n are positive numbers. Z is Ge, Zn, or Ga.) and the like.

[0294] As the Li2S-SiS2 compound, Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, Li2S-SiS2-P2S5-LiCl, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li2SO4, and Li2S-SiS2-LiI can be exemplified. x MO y (x, y are positive numbers. M is P, Si, Ge, B, Al, Ga, or In.) and the like.

[0295] As the Li2S-GeS2 compound, Li2S-GeS2 and Li2S-GeS2-P2S5 and the like can be exemplified.

[0296] The sulfide-based solid electrolyte can be a crystalline material or an amorphous material.

[0297] (Hydride-based solid electrolyte)

[0298] As the hydride-based solid electrolyte material, LiBH4, LiBH4-3KI, LiBH4-P12, LiBH4-P2S5, LiBH4-LiNH2, 3LiBH4-LiI, LiNH2, Li2AlH6, Li(NH2)2I, Li2NH, LiGd(BH4)3Cl, Li2(BH4)(NH2), Li3(NH2)I, and Li4(BH4)(NH2)3, and the like can be listed.

[0299] (Polymer-based solid electrolyte)

[0300] As the polymer-based solid electrolyte, for example, a polyethylene oxide-based high molecular compound, an organic polymer electrolyte including one or more high molecular compounds selected from the group consisting of a polyorganosiloxane chain and a polyoxyalkylene chain, and the like can be listed. In addition, a so-called gel type electrolyte in which a nonaqueous electrolyte solution is held in a high molecular compound can also be used.

[0301] The solid electrolyte can be used in combination with two or more types without impairing the effects of the present application.

[0302] (Conductive material and binder)

[0303] As the conductive material possessed by the positive electrode active material layer 111, the materials described in the above (conductive material) can be used. In addition, the proportion of the conductive material in the positive electrode mixture can also be applied as described in the above (conductive material). In addition, as the binder possessed by the positive electrode, the materials described in the above (binder) can be used.

[0304] (Positive electrode current collector)

[0305] As the positive electrode current collector 112 possessed by the positive electrode 110, the materials described in the above (positive electrode current collector) can be used.

[0306] As the method of supporting the positive electrode active material layer 111 on the positive electrode current collector 112, a method of pressure molding the positive electrode active material layer 111 on the positive electrode current collector 112 can be listed. For the pressure molding, cold pressing or hot pressing can be used.

[0307] Further, the positive electrode active material layer 111 can be formed by using an organic solvent to paste a mixture of the CAM, the solid electrolyte, and the conductive material, and coating the obtained positive electrode active material on at least one surface of the positive electrode current collector 112 and drying and sintering it.

[0308] Further, the positive electrode active material layer 111 can be formed by using an organic solvent to paste a mixture of the CAM, the solid electrolyte, and the conductive material, and coating the obtained positive electrode active material on at least one surface of the positive electrode current collector 112 and drying and sintering it.

[0309] As the organic solvent that can be used in the positive electrode active material, the same solvent as that which can be used in the case of pasting the positive electrode active material described in the above (positive electrode current collector) can be used.

[0310] As the method of coating the positive electrode active material on the positive electrode current collector 112, the method described in the above (positive electrode current collector) can be cited.

[0311] The positive electrode 110 can be manufactured by the above cited methods. As the combination of the specific materials used in the positive electrode 110, the combinations of the CAM described in the present embodiment and those described in Table 1 can be cited.

[0312] [Table 1]

[0313]

[0314] [Table 2]

[0315]

[0316] [Table 3]

[0317]

[0318] (Negative electrode)

[0319] The negative electrode 120 has a negative electrode active material layer 121 and a negative electrode current collector 122. The negative electrode active material layer 121 contains a negative electrode active material. Further, the negative electrode active material layer 121 can also contain a solid electrolyte and a conductive material. The negative electrode active material, the negative electrode current collector, the solid electrolyte, the conductive material, and the binder can use the above described substances.

[0320] As a method of supporting the negative electrode active material layer 121 on the negative electrode current collector 122, a method of using press molding, a method of coating a paste-like negative electrode mixture containing a negative electrode active material on the negative electrode current collector 122 and drying and then pressing and pressure bonding, and a method of coating a paste-like negative electrode mixture containing a negative electrode active material on the negative electrode current collector 122 and drying and then sintering can be exemplified as in the case of the positive electrode 110.

[0321] (Solid electrolyte layer)

[0322] The solid electrolyte layer 130 has the above-described solid electrolyte.

[0323] The solid electrolyte layer 130 can be formed by depositing an inorganic solid electrolyte on the surface of the positive electrode active material layer 111 of the above-described positive electrode 110 by a sputtering method.

[0324] Further, the solid electrolyte layer 130 can be formed by coating a paste-like mixture containing a solid electrolyte on the surface of the positive electrode active material layer 111 of the above-described positive electrode 110 and drying. Press molding can be performed after drying, and further, the solid electrolyte layer 130 can be formed by pressurization by a cold isostatic press (CIP) method.

[0325] The laminated body 100 can be manufactured by laminating the negative electrode 120 in such a manner that the negative electrode active material layer 121 contacts the surface of the solid electrolyte layer 130 using a publicly known method with respect to the solid electrolyte layer 130 provided on the positive electrode 110 as described above.

[0326] In the lithium secondary battery having the above-described configuration, since the CAM uses LiMO manufactured by the above-described embodiment, the first efficiency of the lithium secondary battery using the CAM can be improved.

[0327] Further, the positive electrode having the above-described configuration can improve the first efficiency of the lithium secondary battery since the CAM having the above-described configuration is used.

[0328] Further, the lithium secondary battery having the above-described configuration can be a secondary battery having a high first efficiency since the positive electrode having the above-described configuration is used.

[0329] Embodiment

[0330] Next, the present application is further described in detail through an embodiment.

[0331] <Composition analysis>

[0332] The composition analysis of the MCC manufactured by the method described below is performed by the method described in the above-mentioned "Composition analysis of MCC".

[0333] <Relative standard deviation, mode, and average crystallite diameter of the metal complex compound>

[0334] The relative standard deviation, mode, and average crystallite diameter of the crystallite diameter distribution of the MCC are obtained by the methods described above in <Relative standard deviation of the crystallite diameter distribution of the metal complex compound>, <Mode of the crystallite diameter distribution of the metal complex compound>, and <Average crystallite diameter in the crystallite diameter distribution of the metal complex compound>, respectively.

[0335] <Mode / average crystallite diameter>

[0336] From the values of the mode and average crystallite diameter obtained above, the value of the mode / average crystallite diameter is obtained.

[0337] <d90-d10>

[0338] The d90 and d10 of the MCC are obtained by the above-described "Method for measuring d90 and d10". The d90-d10 is obtained from the obtained d10 and d90.

[0339] <Calculation of initial efficiency>

[0340] The CAM is produced by the method described in the above <Production of lithium metal complex oxide>. Further, the cathode for lithium secondary battery is produced by the method described in the above <Production of cathode for lithium secondary battery>. Further, the lithium secondary battery is produced by the method described in the above <Production of lithium secondary battery>. The initial efficiency is calculated by the method described in the above <Charge / discharge test> using the obtained lithium secondary battery.

[0341] <Example 1>

[0342] First, after adding water to a reaction tank equipped with a stirrer and an overflow pipe, an aqueous sodium hydroxide solution is supplied, and the liquid temperature is maintained at 70°C.

[0343] An aqueous nickel sulfate solution, an aqueous cobalt sulfate solution, and an aqueous aluminum sulfate solution are mixed to prepare a first raw element-containing aqueous solution 1.

[0344] As the second raw element-containing aqueous solution 1, an aqueous solution containing aluminum sulfate is prepared. At this time, the second raw element-containing aqueous solution 1 is prepared so that the ratio S2 / S1 of the total concentration S1 (unit: g / L) of Co and Al in the first raw element-containing aqueous solution 1 to the concentration S2 (unit: g / L) of Al in the second raw element-containing aqueous solution 1 becomes 3.7.

[0345] Next, to the reaction tank, under stirring, the first raw element-containing aqueous solution 1, an aqueous ammonium sulfate solution as a complexing agent are continuously added from the supply port 1, and the second raw element-containing aqueous solution 1 is continuously added from the supply port 2, so that the atomic ratio of Ni to Co to Al in the reaction tank becomes 88.0:9.0:3.0. In addition, the aqueous sodium hydroxide solution is supplied in a timely manner so that the pH of the solution in the reaction tank becomes 11.6 (measured at a liquid temperature of 40°C).

[0346] At this time, the flow rates of the aqueous sodium hydroxide solution, the aqueous ammonium sulfate solution, the first raw element-containing aqueous solution 1, and the second raw element-containing aqueous solution 1 are adjusted under the condition that the flow rate of the first raw element-containing aqueous solution 1 becomes greater than that of the second raw element-containing aqueous solution 1, and the residence time of the coprecipitate in the reaction tank becomes 7.1 hours. Thus, particles of nickel-cobalt-aluminum complex hydroxide are obtained. At this time, N1 / N2 = 1.0.

[0347] The nickel-cobalt-aluminum composite hydroxide 1 as the metal composite compound was obtained by washing the particles of the nickel-cobalt-aluminum composite hydroxide, dehydrating with a centrifugal separator, isolating, and drying at 105°C.

[0348] <Example 2>

[0349] First, after adding water to a reaction tank equipped with a stirrer and an overflow pipe, an aqueous sodium hydroxide solution was supplied, and the liquid temperature was maintained at 55°C.

[0350] An aqueous solution 2 containing raw material elements was prepared by mixing an aqueous nickel sulfate solution and an aqueous cobalt sulfate solution.

[0351] As the aqueous solution 2 containing raw material elements, an aqueous solution containing manganese sulfate was prepared. At this time, the aqueous solution 2 containing raw material elements was prepared in such a manner that the ratio S2 / S1 of the concentration S1 (unit: g / L) of Co in the aqueous solution 2 containing raw material elements 2 to the concentration S2 (unit: g / L) of Mn in the aqueous solution 2 containing raw material elements 2 became 3.9.

[0352] Next, to the reaction tank, under stirring, the aqueous solution 2 containing raw material elements, the aqueous ammonium sulfate solution as the complexing agent were continuously added from the supply port 1 at a ratio of the atomic ratio of Ni to Co to Mn in the reaction tank to become 55.0:20.0:25.0, and the aqueous solution 2 containing raw material elements was continuously added from the supply port 2. In addition, the aqueous sodium hydroxide solution was supplied in time in such a manner that the pH of the solution in the reaction tank became 10.7 (measured at a liquid temperature of 40°C).

[0353] At this time, the flow rates of the aqueous sodium hydroxide solution, the aqueous ammonium sulfate solution, the aqueous solution 2 containing raw material elements, and the aqueous solution 2 containing raw material elements were adjusted under the condition that the flow rate of the aqueous solution 2 containing raw material elements became larger than that of the aqueous solution 2 containing raw material elements, and the residence time of the coprecipitate in the reaction tank became 10.5 hours. Thus, particles of a nickel-cobalt-manganese composite hydroxide were obtained. At this time, N1 / N2 = 1.0.

[0354] The nickel-cobalt-manganese composite hydroxide 1 as the metal composite compound was obtained by washing the particles of the nickel-cobalt-manganese composite hydroxide, dehydrating with a centrifugal separator, isolating, and drying at 105°C.

[0355] <Comparative Example 1>

[0356] First, after adding water to a reaction tank equipped with a stirrer and an overflow pipe, an aqueous sodium hydroxide solution was supplied, and the liquid temperature was maintained at 40°C.

[0357] An aqueous solution 3 containing raw material elements was prepared by mixing an aqueous nickel sulfate solution and an aqueous cobalt sulfate solution.

[0358] As the second raw element-containing aqueous solution 3, an aqueous solution containing aluminum sulfate was prepared. At this time, the first raw element-containing aqueous solution 3 and the second raw element-containing aqueous solution 3 were prepared in such a manner that the ratio S2 / S1 of the total concentration S1 (unit: g / L) of Co of the first raw element-containing aqueous solution 3 to the concentration S2 (unit: g / L) of Al of the second raw element-containing aqueous solution 3 became 0.8.

[0359] Next, into the reaction tank, the first raw element-containing aqueous solution 3, the aqueous ammonium sulfate solution as a complexing agent were continuously added from the supply port 1, and the second raw element-containing aqueous solution 3 was continuously added from the supply port 2, at a ratio of the atomic ratio of Ni to Co to Al in the reaction tank to be 88.0:9.0:3.0, with stirring. The aqueous sodium hydroxide solution was supplied in time in such a manner that the pH of the solution in the reaction tank became 11.9 (measured at a liquid temperature of 40°C).

[0360] At this time, the flow rates of the aqueous sodium hydroxide solution, the aqueous ammonium sulfate solution, the first raw element-containing aqueous solution 3, and the second raw element-containing aqueous solution 3 were adjusted under the condition that the flow rate of the first raw element-containing aqueous solution 3 became larger than that of the second raw element-containing aqueous solution 3, and the residence time of the coprecipitate in the reaction tank became 14.2 hours. Thus, the nickel-cobalt-aluminum composite hydroxide particles were obtained. At this time, N1 / N2 = 1.0.

[0361] The nickel-cobalt-aluminum composite hydroxide particles were washed, dehydrated with a centrifugal separator, isolated, and dried at 105°C to obtain the nickel-cobalt-aluminum composite hydroxide 2 as a metal composite compound.

[0362] <Example 3>

[0363] First, into a reaction tank equipped with a stirrer and an overflow pipe, water was added, and then an aqueous sodium hydroxide solution was supplied to maintain the liquid temperature at 70°C.

[0364] The aqueous nickel sulfate solution and the aqueous cobalt sulfate solution were mixed to prepare the first raw element-containing aqueous solution 4.

[0365] As the second raw element-containing aqueous solution 4, an aqueous solution containing manganese sulfate was prepared. At this time, the first raw element-containing aqueous solution 4 and the second raw element-containing aqueous solution 4 were prepared in such a manner that the ratio S2 / S1 of the concentration S1 (unit: g / L) of Co of the first raw element-containing aqueous solution 4 to the concentration S2 (unit: g / L) of Mn of the second raw element-containing aqueous solution 4 became 166.4.

[0366] Next, to the reaction tank, under stirring, the first raw element-containing aqueous solution 4, the aqueous ammonium sulfate solution as a complexing agent were continuously added from the supply port 1 at a ratio of 90.5:0.5:9.0 of the atomic ratio of Ni to Co to Mn in the reaction tank, and the second raw element-containing aqueous solution 4 was continuously added from the supply port 2. Further, the aqueous sodium hydroxide solution was supplied in time so that the pH of the solution in the reaction tank became 11.6 (measured at a liquid temperature of 40°C).

[0367] At this time, the flow rates of the aqueous sodium hydroxide solution, the aqueous ammonium sulfate solution, the first raw element-containing aqueous solution 4, and the second raw element-containing aqueous solution 4 were adjusted under the condition that the flow rate of the first raw element-containing aqueous solution 4 became larger than that of the second raw element-containing aqueous solution 4, and the residence time of the coprecipitate in the reaction tank became 7.2 hours. Thus, the nickel-cobalt-manganese composite hydroxide particles were obtained. At this time, N1 / N2 = 1.0.

[0368] The nickel-cobalt-manganese composite hydroxide particles were washed, dehydrated with a centrifugal separator, isolated, and dried at 105°C to obtain the nickel-cobalt-manganese composite hydroxide 2 as a metal composite compound.

[0369] <Example 4>

[0370] First, to the reaction tank equipped with a stirrer and an overflow pipe, water was added, and then the aqueous sodium hydroxide solution was supplied to maintain the liquid temperature at 75°C.

[0371] The aqueous nickel sulfate solution and the aqueous cobalt sulfate solution were mixed to prepare the first raw element-containing aqueous solution 5.

[0372] As the second raw element-containing aqueous solution 5, an aqueous solution containing manganese sulfate was prepared. At this time, the first raw element-containing aqueous solution 5 and the second raw element-containing aqueous solution 5 were prepared so that the ratio S2 / S1 of the concentration S1 (unit: g / L) of Co in the first raw element-containing aqueous solution 5 to the concentration S2 (unit: g / L) of Mn in the second raw element-containing aqueous solution 5 became 375.0.

[0373] Next, to the reaction tank, under stirring, the first raw element-containing aqueous solution 5, the aqueous ammonium sulfate solution as a complexing agent were continuously added from the supply port 1 at a ratio of 90.5:0.5:9.0 of the atomic ratio of Ni to Co to Mn in the reaction tank, and the second raw element-containing aqueous solution 5 was continuously added from the supply port 2. Further, the aqueous sodium hydroxide solution was supplied in time so that the pH of the solution in the reaction tank became 11.3 (measured at a liquid temperature of 40°C).

[0374] At this time, the flow rate of the first raw element-containing aqueous solution 5 was made larger than that of the second raw element-containing aqueous solution 5, and the residence time of the coprecipitate in the reaction tank was made 8.5 hours, and the flow rates of the sodium hydroxide aqueous solution, the ammonium sulfate aqueous solution, the first raw element-containing aqueous solution 5, and the second raw element-containing aqueous solution 5 were adjusted. Thus, particles of the nickel-cobalt-manganese composite hydroxide were obtained. At this time, N1 / N2 = 1.0.

[0375] The particles of the nickel-cobalt-manganese composite hydroxide were washed, dehydrated with a centrifugal separator, isolated, and dried at 105°C to obtain the nickel-cobalt-manganese composite hydroxide 3 as a metal composite compound.

[0376] <Example 5>

[0377] First, water was added to a reaction tank equipped with a stirrer and an overflow pipe, and a sodium hydroxide aqueous solution was supplied, and the liquid temperature was maintained at 70°C.

[0378] A nickel sulfate aqueous solution and a manganese sulfate aqueous solution were mixed to prepare the first raw element-containing aqueous solution 6.

[0379] As the second raw element-containing aqueous solution 6, an aqueous solution containing aluminum sulfate was prepared. At this time, the first raw element-containing aqueous solution 6 and the second raw element-containing aqueous solution 6 were prepared in such a manner that the ratio S2 / S1 of the concentration S1 (unit: g / L) of Mn in the first raw element-containing aqueous solution 6 to the concentration S2 (unit: g / L) of Al in the second raw element-containing aqueous solution 6 became 14.7.

[0380] Next, to the reaction tank, under stirring, the first raw element-containing aqueous solution 6, the ammonium sulfate aqueous solution as a complexing agent were continuously added from the supply port 1, and the second raw element-containing aqueous solution 6 was continuously added from the supply port 2, in such a manner that the atomic ratio of Ni to Mn to Al in the reaction tank became 93.0:3.5:3.5. In addition, the sodium hydroxide aqueous solution was supplied in a timely manner in such a manner that the pH of the solution in the reaction tank became 10.7 (measured at a liquid temperature of 40°C).

[0381] At this time, the flow rate of the first raw element-containing aqueous solution 6 was made larger than that of the second raw element-containing aqueous solution 6, and the residence time of the coprecipitate in the reaction tank was made 9.9 hours, and the flow rates of the sodium hydroxide aqueous solution, the ammonium sulfate aqueous solution, the first raw element-containing aqueous solution 6, and the second raw element-containing aqueous solution 6 were adjusted. Thus, particles of the nickel-manganese-aluminum composite hydroxide were obtained. At this time, N1 / N2 = 1.0.

[0382] The particles of the nickel-manganese-aluminum composite hydroxide were washed, dehydrated with a centrifugal separator, isolated, and dried at 105°C to obtain the nickel-manganese-aluminum composite hydroxide 1 as a metal composite compound.

[0383] In Table 4 below, values of S2 / S1, N1 / N2, residence time, composition of the obtained MCC, relative standard deviation, mode, average crystallite diameter, mode / average crystallite diameter, and d90-d10, and initial efficiency of the lithium secondary battery are respectively described.

[0384]

[0385] It was confirmed that the lithium secondary battery using the CAM using the MCC of Examples 1 to 5 as a raw material had a higher initial efficiency than the case where the MCC of Comparative Example 1 was used.

[0386] Explanation of symbols

[0387] 1: separator, 2: positive electrode, 3: negative electrode, 4: electrode group, 5: battery can, 6: electrolyte, 7: top insulator, 8: sealing body, 10: lithium secondary battery, 21: positive electrode lead wire, 31: negative electrode lead wire, 100: laminate, 110: positive electrode, 111: positive electrode active material layer, 112: positive electrode current collector, 113: external terminal, 120: negative electrode, 121: negative electrode active material layer, 122: negative electrode current collector, 123: external terminal, 130: solid electrolyte layer, 200: outer packaging body, 200a: opening, 1000: all-solid-state lithium secondary battery.

Claims

1. A metal complex compound, wherein, In powder X-ray diffraction measurement using CuKα rays, the relative standard deviation of the volume-based crystallite diameter distribution calculated from the diffraction peaks in the range of 2θ = 19 ± 1° is 0.50 or greater, which is represented by the following composition formula (I), The mode of the microcrystal diameter distribution is The above, The average crystallite diameter in the crystallite diameter distribution is The above, which satisfies the following formula (A), Ni 1-x-y Co x M y O z (OH) 2-α Formula (I) The composition formula (I) satisfies 0 < x ≤ 0.5, 0 < y ≤ 0.5, 0 < x + y < 1, 0 ≤ z ≤ 3, -0.5 ≤ α ≤ 2, and α - z < 2, M is one or more elements selected from the group consisting of Mn, Fe, Cu, Ti, Mg, Al, Zn, Sn, Zr, Nb, Ga, W, Mo, B, and Si, In formula (A), d10 is the crystal diameter at 10% from the small diameter side with respect to the total area of the area surrounded by the crystal diameter distribution function curve and the horizontal axis in a crystal diameter distribution function curve in which the crystal diameter on a volume basis in the crystal diameter distribution is taken as the horizontal axis and the probability density function of the crystal with respect to the crystal diameter is taken as the vertical axis, d90 is the crystal diameter at 90% from the small diameter side with respect to the total area, and d10 and d90 are in 2. The metal complex compound according to claim 1, wherein, The mode of the diameter distribution of the microcrystals is The above and The following.

3. The metal complex compound according to claim 1 or 2, wherein, The average crystallite diameter in the crystallite diameter distribution is The above and The following.

4. The metal complex compound according to claim 1 or 2, wherein, The ratio of the mode of the crystallite diameter distribution to the average crystallite diameter in the crystallite diameter distribution, that is, the mode / average crystallite diameter is 0.57 or less.

5. The metal complex compound according to claim 1 or 2, wherein, d90-d10 is The above and The following.

6. The metal complex compound according to claim 1 or 2, wherein, In powder X-ray diffraction measurement using CuKα rays, the relative standard deviation of the volume-based crystallite diameter distribution calculated from the diffraction peaks in the range of 2θ = 19 ± 1° is 0.70 or greater and 1.30 or less.

7. The metal complex compound according to claim 1 or 2, wherein, The mode of the microcrystal diameter distribution is The above and The following.

8. The metal complex compound according to claim 1 or 2, wherein, The average crystallite diameter in the crystallite diameter distribution is The above and Below.

9. The metal complex compound according to claim 1 or 2, wherein, The ratio of the mode of the crystallite diameter distribution to the average crystallite diameter in the crystallite diameter distribution, that is, the mode / average crystallite diameter is 0.15 or greater and 0.56 or less.

10. A method for producing a lithium metal complex oxide, comprising a mixing step of mixing the metal complex compound according to any one of claims 1 to 9 with a lithium compound, and a firing step of firing the obtained mixture at a temperature of 500°C or higher and 1000°C or lower in an oxygen-containing atmosphere.

11. A method for producing the metal complex compound according to any one of claims 1 to 9, comprising a slurry preparation step of supplying a first raw material element-containing aqueous solution containing Ni and other elements, a second raw material element-containing aqueous solution containing other elements, and an alkaline aqueous solution to a reaction tank to obtain a co-precipitate-containing slurry, and a separation step of dehydrating and drying the co-precipitate-containing slurry, in the slurry preparation step, the first raw material element-containing aqueous solution and the second raw material element-containing aqueous solution are separately supplied from different supply ports under a condition that the total flow rate of the first raw material element-containing aqueous solution becomes the largest, the total concentration of the other elements in the first raw material element-containing aqueous solution is set to S1, and the total concentration of the other elements in the second raw material element-containing aqueous solution is set to S2, and when the ratio of S2 to S1, that is, S2 / S1, satisfies 0.8 < S2 / S1 ≤ 400.0, the units of S1 and S2 are g / L, the other elements in the first raw material element-containing aqueous solution and the other elements in the second raw material element-containing aqueous solution are each independently one or more elements selected from the group consisting of Co and an element M, the element M being one or more elements selected from the group consisting of Mn, Fe, Cu, Ti, Mg, Al, Zn, Sn, Zr, Nb, Ga, W, Mo, B, and Si, in the slurry preparation step, the flow rate of the liquid raw material supplied to the reaction tank is adjusted under a condition that the residence time of the co-precipitate in the reaction tank in the co-precipitate-containing slurry is 10.5 hours or less.

12. The method of producing a metal complex compound according to claim 11, wherein The S2 / S1 satisfies 0.8 < S2 / S1 ≤ 2 10.

0.

13. The method of producing a metal complex compound according to claim 11 or 12, wherein, In the slurry preparation step, when the total number of supply ports for supplying the first raw element-containing aqueous solution in the reaction tank is set to N1 and the total number of supply ports for supplying raw element-containing aqueous solutions other than the first raw element-containing aqueous solution is set to N2, N1 / N2 ≥ 1.0 is satisfied.

14. The method of producing a metal complex compound according to claim 11 or 12, wherein, In the slurry preparation step, the flow rate of the liquid raw material supplied to the reaction tank is adjusted so that the residence time of the coprecipitate in the reaction tank in the coprecipitate-containing slurry is 4.0 hours or more and 9.0 hours or less.

Images