Precursor for positive electrode active material for lithium secondary battery, lithium metal composite oxide, positive electrode active material for lithium secondary battery, positive electrode for lithium secondary battery and lithium secondary battery

Abstract

A precursor for a positive electrode active material of a lithium secondary battery, comprising at least Ni and element M, wherein element M is one or more elements selected from the group consisting of Co, Mn, Fe, Cu, Ti, Mg, Al, W, Mo, Nb, Zn, Sn, Zr, Ga, V, B, Si, S, and P, wherein the value of the ratio D60 / D10 of particle diameter D60 (μm) at which the cumulative volume from the small particle side is 60% and D10 (μm) at which the cumulative volume from the small particle side is 10% when the total is 100% in the cumulative particle size distribution curve obtained by measuring by a laser diffraction particle size distribution measuring device is 2.0 or less, and the BET specific surface area is 20 m² / g or more.

Description

Technology Field

[0001] The present invention relates to a precursor for a positive electrode active material for a lithium secondary battery, a lithium metal composite oxide, a positive electrode active material for a lithium secondary battery, a positive electrode for a lithium secondary battery, and a lithium secondary battery.

[0002] The present application claims priority based on Japanese Patent Application No. 2020-116515 filed in Japan on July 6, 2020, and incorporates the contents thereof herein. Background Technology

[0003] Lithium metal composite oxides are used as positive electrode active materials for lithium secondary batteries. Lithium secondary batteries are already being commercialized not only for small power sources such as mobile phones and laptop computers, but also for medium and large power sources such as automobiles and power storage.

[0004] Lithium metal composite oxides are manufactured by using a metal composite compound, for example, containing nickel or cobalt, as a precursor, mixing the precursor with a lithium compound, and calcining the mixture. In the process of manufacturing the precursor, by controlling the physical properties of the resulting precursor, a lithium metal composite oxide capable of exhibiting desired characteristics can be manufactured.

[0005] For example, Patent Document 1 describes uniformity (D) obtained from particle size distribution measurement. 60 / D 10 Lithium cobaltate with a specific range is described. Patent Document 1 controls the properties of lithium cobaltate produced by using granular cobaltate satisfying specific properties as a precursor. Prior art literature

[0006] JP-B-4412568 The problem to be solved

[0007] As the application fields of lithium secondary batteries advance, for example, further improvement in cycle retention rate is required.

[0008] The present invention has been made in consideration of the above circumstances and aims to provide a precursor for a positive electrode active material for a lithium secondary battery, a lithium metal composite oxide, a positive electrode active material for a lithium secondary battery, a positive electrode for a lithium secondary battery, and a lithium secondary battery, which can produce a lithium metal composite oxide capable of improving the cycle retention rate of a lithium secondary battery compared to conventional methods. means of solving the problem

[0009] [1] A precursor for a positive electrode active material of a lithium secondary battery containing at least Ni and element M, wherein element M is one or more elements selected from the group consisting of Co, Mn, Fe, Cu, Ti, Mg, Al, W, Mo, Nb, Zn, Sn, Zr, Ga, V, B, Si, S and P, and the particle size D such that the cumulative volume from the small particle side is 60% when the total is set to 100% in the cumulative particle size distribution curve obtained by measuring the precursor for the positive electrode active material of a lithium secondary battery by a laser diffraction particle size distribution measuring device. 60 (㎛) and particle size D at 10% 10 Ratio D of (㎛) 60 / D 10 A precursor for a positive electrode active material of a lithium secondary battery, wherein the value of is 2.0 or less and the BET specific surface area is 20 m² / g or more.

[0010] [2] A precursor for a lithium secondary battery positive electrode active material as described in [1], represented by the following composition formula (A).

[0011] Ni 1-x M x O z (OH) 2-t ··· (A)

[0012] (In compositional formula (A), 0 < x ≤ 0.3, 0 ≤ z ≤ 3, and -0.5 ≤ t ≤ 2 are satisfied, and M is one or more elements selected from the group consisting of Co, Mn, Fe, Cu, Ti, Mg, Al, W, Mo, Nb, Zn, Sn, Zr, Ga, V, B, Si, S, and P)

[0013] [3] A precursor for a lithium secondary battery positive electrode active material as described in [1] or [2], satisfying the following formula (B).

[0014] 6 / (D 50 × S) ≤ 0.035 g / ㎤···(B)

[0015] (D 50 ...is the particle diameter (μm) at which the cumulative volume from the small particle side is 50% when the total is set to 100% in the above cumulative particle size distribution curve. S is the BET specific surface area (m² / g) of the positive electrode active material precursor for the above lithium secondary battery.

[0016] [4] The above D 10 (㎛) and, in the above cumulative particle size distribution curve, particle diameter D at which the cumulative volume from the fine particle side is 50% when the whole is set to 100%. 50 Ratio D of (㎛) 10 / D 50 A precursor for a lithium secondary battery positive electrode active material described in any one of [1] to [3], having a value of 0.55 or higher.

[0017] [5] A precursor for a lithium secondary battery positive electrode active material described in any one of [1] to [4], having a BET specific surface area of ​​80 m² / g or less.

[0018] [6] A lithium metal composite oxide having a layered structure, containing at least Li and Ni and element M, wherein the element M is one or more elements selected from the group consisting of Co, Mn, Fe, Cu, Ti, Mg, Al, W, Mo, Nb, Zn, Sn, Zr, Ga, V, B, Si, S and P, and the lithium metal composite oxide is measured by a laser diffraction particle size distribution measuring device, and in the obtained cumulative particle size distribution curve, when the total is set to 100%, the particle size D such that the cumulative volume from the small particle side is 60%. 60 (㎛) and particle size D at 10% 10 Ratio D of (㎛) 60 / D 10 A lithium metal composite oxide having a value of 2.5 or less and a BET specific surface area of ​​0.30 m² / g or more and 0.60 m² / g or less.

[0019] [7] A lithium metal composite oxide as described in [6], represented by the following composition formula (1).

[0020] Li[Li m (Ni (1-n) M n ) 1-m ]O2··· (1)

[0021] (However, M is one or more elements selected from the group consisting of Co, Mn, Fe, Cu, Ti, Mg, Al, W, Mo, Nb, Zn, Sn, Zr, Ga, V, B, Si, S, and P, satisfying -0.1 ≤ m ≤ 0.2, 0 < n ≤ 0.3, and 0 < m + n < 0.3.)

[0022] [8] Above D 10 (㎛) and, in the above cumulative particle size distribution curve, particle diameter D at which the cumulative volume from the fine particle side is 50% when the whole is set to 100%. 50 Ratio D of (㎛) 10 / D 50Lithium metal composite oxide described in [6] or [7], which is 0.40 or more and less than 0.60.

[0023] [9] A lithium metal composite oxide described in any one of [6] to [8], wherein the ratio α / β of the crystallite size α obtained from the peak in the range 2θ = 18.7 ± 2° and the crystallite size β obtained from the peak in the range 2θ = 44.6 ± 2° in X-ray diffraction measurements using CuKα rays is 1.71 or greater and 2.50 or less.

[0024]

[10] [6] ~ [9] A positive electrode active material for a lithium secondary battery comprising a lithium metal composite oxide as described in any one of

[10] [6] ~ [9].

[0025]

[11] A positive electrode for a lithium secondary battery comprising the positive electrode active material for a lithium secondary battery described in

[10] .

[0026]

[12] A lithium secondary battery having a positive electrode for a lithium secondary battery as described in

[11] . Effects of the invention

[0027] According to the present invention, a precursor for a positive electrode active material for a lithium secondary battery, a lithium metal composite oxide, a positive electrode active material for a lithium secondary battery, a positive electrode for a lithium secondary battery, and a lithium secondary battery can be provided, which can produce a lithium metal composite oxide with a high cycle retention rate for a lithium secondary battery. Brief explanation of the drawing

[0028] Figure 1a is a schematic diagram showing an example of a lithium secondary battery. FIG. 1b is a schematic diagram showing an example of a lithium secondary battery. FIG. 2 is a schematic diagram showing an example of a stirring means used in the present embodiment. Figure 3 is a schematic diagram of a cross-section of a Taylor vortex continuous stirring reaction device. Figure 4 is a schematic diagram of a crystallograph having a crystal structure belonging to space group R-3m. FIG. 5 is a schematic diagram showing a laminated structure equipped with an all-solid-state lithium-ion secondary battery. Figure 6 is a schematic diagram showing the overall configuration of an all-solid-state lithium-ion secondary battery. Specific details for implementing the invention

[0029] <Justice>

[0030] In this specification, "precursor for a positive electrode active material of a lithium secondary battery" may be referred to as "precursor."

[0031] In this specification, lithium metal composite oxide is hereinafter referred to as "LiMO".

[0032] Unless otherwise specified, the notation "Li" indicates that it is the element Li, not the metallic element Li. The same applies to the notations for other elements such as Ni, Co, and Mn.

[0033] In this specification, the positive electrode active material for lithium secondary batteries may be referred to as "CAM" as an abbreviation for "Cathode Active Material for lithium secondary batteries".

[0034] In this specification, “cycle retention rate” is measured by the following method. “High cycle retention rate” means that the value of the cycle retention rate exceeds 82%.

[0035] [Method for Measuring Cycle Retention Rate]

[0036] (Fabrication of positive electrodes for lithium secondary batteries)

[0037] A paste-like positive electrode composite is prepared by adding and mixing LiMO, a conductive material (acetylene black), and a binder (PVdF) in a ratio of LiMO : conductive material : binder = 92 : 5 : 3 (mass ratio). When preparing the positive electrode composite, N-methyl-2-pyrrolidone is used as an organic solvent.

[0038] The obtained positive electrode composite is coated onto an Al foil with a thickness of 40 μm that serves as a current collector, vacuum dried at 150°C for 8 hours, and a positive electrode for a lithium secondary battery is obtained. The electrode area of ​​this positive electrode for a lithium secondary battery is set to 1.65 cm².

[0039] (Production of lithium secondary batteries (coin-type half cells))

[0040] The following operations are performed inside an argon-filled glove box.

[0041] The positive electrode for a lithium secondary battery produced in (Fabrication of a positive electrode for a lithium secondary battery) was placed with the aluminum foil side facing downward on the lower cover of a part for a coin-type battery R2032 (manufactured by Hosen Corporation), and a separator (porous film made of polyethylene) was placed on top of it. 300 μl of electrolyte was injected into it. The electrolyte used is a mixture of ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate in a 30:35:35 (volume ratio) ratio, in which LiPF6 is dissolved at a ratio of 1.0 mol / l.

[0042] Next, using metallic lithium as the negative electrode, the negative electrode is placed on the upper side of a laminated film separator, an upper cover is formed with a gasket interposed, and a lithium secondary battery (coin-type half cell R2032. Hereinafter referred to as "half cell") is manufactured by caulking with a caulking machine.

[0043] (Measurement of cycle maintenance rate)

[0044] First, the separator and positive electrode composite layer are sufficiently impregnated with electrolyte by leaving the coin-type lithium secondary battery at room temperature for 10 hours.

[0045] Next, the initial charge and discharge are performed by charging at a constant current of 1 mA to 4.3 V at room temperature, followed by charging at a constant voltage of 4.3 V for 5 hours, and then discharging at a constant current of 1 mA to 2.5 V.

[0046] Measure the discharge capacity, and the obtained value is called the “initial discharge capacity” (mAh / g).

[0047] Measure the charging capacity, and the obtained value is called the “initial charging capacity” (mAh / g).

[0048] After the initial charge and discharge, the charging and discharging are repeated at 1 mA and 1 mA, respectively, under the same conditions as the initial charge and discharge.

[0049] After that, the discharge capacity (mAh / g) at the 50th cycle is measured.

[0050] The cycle retention rate is calculated using the following formula from the initial discharge capacity and the 50th cycle discharge capacity. A higher cycle retention rate indicates that the decrease in battery capacity after repeated charging and discharging is suppressed, which is desirable for battery performance.

[0051] Cycle retention rate (%) = Discharge capacity at 50th cycle (mAh / g) ÷ Initial discharge capacity (mAh / g) × 100

[0052] [Measurement of Cumulative Volumetric Particle Size Distribution]

[0053] In this specification, the cumulative volume particle size distribution of the precursor and LiMO is measured by laser diffraction scattering. A particle size distribution measuring device may be used, for example, the MasterCider 2000 manufactured by Malvern Co.

[0054] In the obtained cumulative particle size distribution curve, when the total is set to 100%, the particle size at which the cumulative volume ratio from the finer particle side is 10% is D. 10 (㎛), the particle size that becomes 50% is D 50 (㎛), particle size D that becomes 60% 60 (㎛)

[0055] [Measurement of BET Specific Surface Area]

[0056] In this specification, the BET specific surface area of ​​the precursor and LiMO is measured using a BET specific surface area measuring device. As a BET specific surface area measuring device, for example, the fluid-type automatic specific surface area measuring device, Flosorb 2300II manufactured by Shimadzu Corporation, can be used. Specifically, 1 g of powder of the precursor or LiMO is dried in a nitrogen atmosphere at 105°C for 30 minutes, and then measured using a BET specific surface area measuring device.

[0057] [Composition Analysis of LiMO]

[0058] In this specification, the composition of LiMO is measured by dissolving a precursor or LiMO powder in hydrochloric acid and then using an ICP emission spectroscopic analyzer. For example, the Optima 7300 manufactured by PerkinElmer Inc. can be used as the ICP emission spectroscopic analyzer.

[0059] [Powder X-ray Diffraction Measurement]

[0060] In this specification, powder X-ray diffraction measurements can be performed by an X-ray diffraction device. As an X-ray diffraction device, for example, Ultima IV manufactured by Rigaku Co., Ltd. can be used.

[0061] Specifically, LiMO powder is loaded onto a dedicated substrate, and using a Cu-Kα source, measurements are performed under conditions of a diffraction angle 2θ = 10° to 90°, a sampling width of 0.02°, and a scan speed of 4° / min to obtain the powder X-ray diffraction spectrum. From the obtained X-ray diffraction spectrum, peaks within the range of 2θ = 18.7 ± 2° and peaks within the range of 2θ = 44.6 ± 2° are determined.

[0062] Using the integrated powder X-ray analysis software JADE, the full width at half maximum A of the diffraction peak within the range of 2θ = 18.7 ± 2° and the full width at half maximum B of the diffraction peak within the range of 2θ = 44.6 ± 2° are calculated from the powder X-ray diffraction spectrum.

[0063] The diffraction angle of the peak and the obtained full width at half maximum are substituted into the Scherrer equation (D = Kλ / Ecosθ (D: crystallite size, K: Scherrer constant, E: full width at half maximum of the peak)), and crystallite sizes α and β are calculated, respectively.

[0064] In addition, calculating the crystallite size from the full width at half maximum of a diffraction peak using the Scherrer equation is a method that has been used conventionally (for example, see "X-ray Structural Analysis - Determining Atomic Arrangement -", 3rd edition, April 30, 2002, by Yoshio Waseda and Eiichiro Matsubara).

[0065] <Precursor>

[0066] The present embodiment is a precursor containing at least Ni and element M. The precursor does not contain Li.

[0067] Element M is one or more elements selected from the group consisting of Co, Mn, Fe, Cu, Ti, Mg, Al, W, Mo, Nb, Zn, Sn, Zr, Ga, V, B, Si, S, and P.

[0068] LiMO can be manufactured by mixing a precursor and a lithium compound and calcining them.

[0069] [D 60 / D 10 ]

[0070] The precursor is, D 60 and D 10 Of D 60 / D 10 The value of is 2.0 or less, preferably 1.99 or less, more preferably 1.98 or less, and even more preferably 1.97 or less.

[0071] D 60 / D 10The closer it is to 1, the more the particle size distribution has a narrower peak width. In this specification, "particle size distribution with a narrow peak width" may be described as "sharp particle size distribution."

[0072] D 60 / D 10 The lower limit of is preferably as close to 1. Examples of lower limits include 1.00 or higher, 1.10 or higher, 1.20 or higher, and 1.30 or higher.

[0073] D 60 / D 10 The upper and lower limits of can be combined arbitrarily.

[0074] Examples of combinations include D 60 / D 10 Examples include 1.00 or more and 2.00 or less, 1.10 or more and 1.99 or less, 1.20 or more and 1.98 or less, and 1.30 or more and 1.97 or less.

[0075] D 60 / D 10 The precursor satisfying the aforementioned specific range means having a sharp particle size distribution, regardless of the shape of the particle size distribution. D 60 / D 10 Silver is a physical property that is also used as one of the evaluation indicators for powder flow characteristics.

[0076] [BET Specific Surface Area]

[0077] The precursor has a BET specific surface area of ​​20 m² / g or more, preferably 26 m² / g or more, and more preferably 30 m² / g or more.

[0078] The precursor preferably has a BET specific surface area of ​​80 m² / g or less, more preferably 76 m² / g or less, and even more preferably 72 m² / g or less.

[0079] The above upper and lower limits of the BET specific surface area may be combined arbitrarily. Examples of combinations include a BET specific surface area of ​​20 m² / g or more and 80 m² / g or less, 26 m² / g or more and 76 m² / g or less, and 30 m² / g or more and 72 m² / g or less.

[0080] D 60 / D 10 LiMO prepared using a precursor having a BET specific surface area of ​​20 m² / g or more and a value of 2.0 or less can improve the cycle retention rate of a lithium secondary battery when used as a CAM. The reason for this is thought to be as follows.

[0081] LiMO prepared using the precursor of the present embodiment as a raw material is D 60 / D 10 It is believed that the value of is close to 1, indicating a sharp particle size distribution. Particles exhibiting a sharp particle size distribution have a small proportion of secondary particles formed by the aggregation of primary particles. In such a CAM containing LiMO, the interfaces between primary particles are small, making it difficult for LiMO particles to crack during charging and discharging.

[0082] New surfaces formed by particle cracking decompose the electrolyte, causing gas generation. Additionally, the fine gaps between new surfaces can act as resistance to the movement of lithium ions.

[0083] LiMO manufactured using the precursor of the present embodiment as a raw material is less prone to cracking of LiMO particles, which can be a resistance to the movement of lithium ions. For this reason, when used as a CAM, the cycle retention rate of a lithium secondary battery can be improved.

[0084] Using a precursor with a BET specific surface area of ​​20 m² / g or more can increase reactivity with Li during the process of calcining a mixture of the precursor and a lithium compound. When such a precursor is used as a raw material, it is easy to obtain LiMO with a BET specific surface area of ​​0.30 m² / g or more and in which lithium ions are uniformly distributed within the LiMO particles.

[0085] In LiMO with a BET specific surface area of ​​less than 0.30 m² / g, the crystals of LiMO tend to grow excessively, and the contact area between LiMO particles tends to decrease. In this case, the resistance to the movement of lithium ions on the surface of LiMO may increase.

[0086] LiMO manufactured using the precursor of the present embodiment as a raw material does not undergo excessive crystal growth, so it is difficult to increase the resistance to lithium ion movement.

[0087] In addition, LiMO manufactured using the precursor of the present embodiment as a raw material tends to have lithium ions uniformly distributed within the particles. Such LiMO tends to have improved lithium ion conductivity. When such LiMO is used as a CAM, the cycle retention rate of a lithium secondary battery can be improved.

[0088] If a precursor with a BET specific surface area of ​​80 m² / g or less is used as a raw material, it is easy to obtain LiMO with a BET specific surface area of ​​0.60 m² / g or less.

[0089] A CAM using LiMO with a BET specific surface area below the upper limit is less likely to have an excessively increased contact area with the electrolyte, and irreversible reactions are less likely to be suppressed. Here, "irreversible reaction" refers to a reaction other than the movement of lithium ions when charging and discharging are repeated, for example.

[0090] LiMO manufactured using the precursor of the present embodiment as a raw material is less likely to have an excessively increased contact area with the electrolyte when used as a CAM. For this reason, irreversible reactions are easily suppressed, and the cycle retention rate of the lithium secondary battery can be improved.

[0091] [furtherance]

[0092] It is preferable that the precursor satisfies the following composition formula (A).

[0093] Ni 1-x M x O z (OH) 2-t ··· (A)

[0094] (In compositional formula (A), 0 < x ≤ 0.3, 0 ≤ z ≤ 3, and -0.5 ≤ t ≤ 2 are satisfied, and M is one or more elements selected from the group consisting of Co, Mn, Fe, Cu, Ti, Mg, Al, W, Mo, Nb, Zn, Sn, Zr, Ga, V, B, Si, S, and P)

[0095] As for the lower limit of x, 0.01 is preferred, 0.02 is more preferred, and 0.03 is particularly preferred. As for the upper limit of x, 0.44 is preferred, 0.42 is more preferred, and 0.40 is particularly preferred.

[0096] The upper and lower limits of x mentioned above can be combined arbitrarily.

[0097] Examples of combinations include 0.01 ≤ x ≤ 0.44, which is preferable, 0.02 ≤ x ≤ 0.42, which is more preferable, and 0.03 ≤ x ≤ 0.40, which is particularly preferable.

[0098] As for the lower limit of z, 0.02 is preferred, 0.03 is more preferred, and 0.05 is particularly preferred. As for the upper limit of z, 0.50 is preferred, 0.40 is more preferred, and 0.30 is particularly preferred. The upper and lower limits may be combined arbitrarily.

[0099] Examples of combinations include 0.02 ≤ z ≤ 0.50, which is preferable, 0.03 ≤ z ≤ 0.40, which is more preferable, and 0.05 ≤ z ≤ 0.30, which is particularly preferable.

[0100] As for the lower limit of t, -0.45 is preferred, -0.40 is more preferred, and -0.35 is particularly preferred. As for the upper limit of t, 1.8 is preferred, 1.6 is more preferred, and 1.4 is particularly preferred. The above upper and lower limits may be combined arbitrarily.

[0101] Examples of combinations include -0.45 ≤ t ≤ 1.8, which is preferable, -0.40 ≤ t ≤ 1.6, which is more preferable, and -0.35 ≤ t ≤ 1.4, which is particularly preferable.

[0102] It is desirable that the composition formula (A) satisfies t - z < 0.

[0103] [Equation (B)]

[0104] It is preferable that the precursor satisfies the following formula (B).

[0105] 6 / (D 50 × S) ≤ 0.035 g / ㎤···(B)

[0106] (D 50 (㎛) is the particle size at which the cumulative volume from the fine particle side is 50% when the total is set to 100% in the above cumulative particle size distribution curve. S is the BET specific surface area (m² / g) of the precursor.

[0107] 6 / (D 50 The value of × S) is more preferably 0.034 g / cm³ or less, and even more preferably 0.033 g / cm³ or less. 6 / (D 50 The lower limit of × S) can be, for example, 0.001 g / cm³ or more, 0.002 g / cm³ or more, or 0.003 g / cm³ or more.

[0108] 6 / (D 50The upper and lower limits of the value of × S) can be arbitrarily combined.

[0109] An example of a combination is 0.001 g / cm³ ≤ 6 / (D 50 × S) ≤ 0.035 g / ㎤, 0.002 g / ㎤ ≤ 6 / (D 50 × S) ≤ 0.034 g / ㎤, 0.003 g / ㎤ ≤ 6 / (D 50 × S) ≤ 0.033 g / cm³ can be cited.

[0110] A precursor satisfying Equation (B) has a larger BET specific surface area than a precursor with the same particle size and reacts easily with lithium compounds during the calcination process. When such a precursor is used as a raw material, it is easy to obtain LiMO in which lithium ions are uniformly distributed within the particles.

[0111] LiMO produced using the precursor of the present embodiment as a raw material tends to have lithium ions uniformly distributed within the particles. For this reason, when used as a CAM, the cycle retention rate of a lithium secondary battery can be improved.

[0112] [D 10 / D 50 ]

[0113] The precursor is, D 10 and D 50 Of D 10 / D 50 It is desirable that the value of is 0.55 or higher, more desirable that it is 0.56 or higher, and even more desirable that it is 0.57 or higher. D 10 / D 50 The upper limits of can be, for example, 1.0 or less, 0.90 or less, or 0.80 or less. D 10 / D 50 The above upper and lower limits can be combined arbitrarily.

[0114] Examples of combinations include D 10 / D 50Examples include 0.55 or higher and 1.0 or lower, 0.56 or higher and 0.90 or lower, and 0.57 or higher and 0.80 or lower.

[0115] D 10 / D 50 LiMO manufactured using a precursor with a value of 0.55 or higher as a raw material has a low proportion of particles with small particle sizes, i.e., particles with a large BET specific surface area. In CAM using LiMO with a low proportion of particles with a large BET specific surface area, the contact area with the electrolyte is difficult to increase excessively, and irreversible reactions are easily suppressed.

[0116] LiMO manufactured using the precursor of the present embodiment as a raw material is less likely to have an excessively increased contact area with the electrolyte when used as a CAM. For this reason, irreversible reactions are easily suppressed, and the cycle retention rate of the lithium secondary battery can be improved.

[0117] <LiMO>

[0118] This embodiment is a LiMO having a layered structure.

[0119] LiMO contains at least Li, Ni, and element M.

[0120] Element M is one or more elements selected from the group consisting of Co, Mn, Fe, Cu, Ti, Mg, Al, W, Mo, Nb, Zn, Sn, Zr, Ga, V, B, Si, S, and P.

[0121] [D 60 / D 10 ]

[0122] LiMO is, D 60 and D 10 Of D 60 / D 10 It is preferable that the value of be 2.50 or less, more preferable that it be 2.45 or less, even more preferable that it be 2.42 or less, and even more preferable that it be 2.40 or less.

[0123] D 60 / D10 The closer it is to 1, the sharper the particle size distribution.

[0124] D 60 / D 10 The lower limit of is preferably as close to 1 as possible, but examples of lower limits include 1.00 or higher, 1.10 or higher, 1.20 or higher, and 1.30 or higher.

[0125] D 60 / D 10 The upper and lower limits of can be combined arbitrarily.

[0126] Examples of combinations include non-D 60 / D 10 Examples include 1.00 or more and 2.50 or less, 1.10 or more and 2.45 or less, 1.20 or more and 2.42 or less, and 1.30 or more and 2.40 or less.

[0127] [BET Specific Surface Area]

[0128] LiMO has a BET specific surface area of ​​0.30 m² / g or more, preferably 0.31 m² / g or more, and more preferably 0.32 m² / g or more.

[0129] LiMO has a BET specific surface area of ​​0.60 m² / g or less, preferably 0.59 m² / g or less, and more preferably 0.55 m² / g or less.

[0130] The above upper and lower limits of the BET specific surface area can be combined arbitrarily. Examples of combinations include the BET specific surface area of ​​LiMO being 0.30 m² / g or more and 0.60 m² / g or less, 0.31 m² / g or more and 0.59 m² / g or less, and 0.32 m² / g or more and 0.55 m² / g or less.

[0131] D 60 / D 10 LiMO satisfying this 2.5 or less and a BET specific surface area of ​​0.30 m² / g or more and 0.60 m² / g or less can improve the cycle retention rate of a lithium secondary battery when used as a CAM. The reason is thought to be as follows.

[0132] The LiMO of this embodiment is D 60 / D 10 It has a sharp particle size distribution with a value close to 1. Particles exhibiting a sharp particle size distribution have a small proportion of secondary particles formed by the aggregation of primary particles. In a CAM using such LiMO, the interface between primary particles is small, making it difficult for LiMO particles to crack during charging and discharging.

[0133] When the electrolyte comes into contact with the newly formed surface created by the cracking of LiMO particles, the electrolyte decomposes and causes gas generation. In addition, the fine gaps between the newly formed surfaces can act as resistance when lithium ions move.

[0134] D 60 / D 10 LiMO within the aforementioned specific range is resistant to particle cracking and resistant to lithium ion movement. For this reason, when used as a CAM, it can improve the cycle retention rate of a lithium secondary battery.

[0135] LiMO having a BET specific surface area within the above specific range is a particle that has been properly crystal-grown, and it is easy to reduce the resistance to lithium ion movement on the surface of the LiMO particle.

[0136] In addition, when the above LiMO is used as a CAM, the contact area with the electrolyte is difficult to increase excessively, and irreversible reactions are easily suppressed.

[0137] LiMO having a BET specific surface area within the above specific range is less likely to have an excessively increased contact area with the electrolyte when used as a CAM, and irreversible reactions are less likely to be suppressed. For this reason, the cycle retention rate of a lithium secondary battery can be improved.

[0138] [furtherance]

[0139] It is desirable that LiMO satisfies the following composition formula (1).

[0140] Li[Li m (Ni (1-n) M n ) 1-m ]O2··· (1)

[0141] (However, M is one or more elements selected from the group consisting of Co, Mn, Fe, Cu, Ti, Mg, Al, W, Mo, Nb, Zn, Sn, Zr, Ga, V, B, Si, S, and P, satisfying -0.1 ≤ m ≤ 0.2, 0 < n ≤ 0.3, and 0 < m + n < 0.3.)

[0142] In the composition formula (1), m is preferably -0.05 or higher, more preferably -0.02 or higher, and particularly preferably 0 or higher. Also, m is preferably 0.10 or lower, more preferably 0.08 or lower, and particularly preferably 0.06 or lower.

[0143] The upper and lower limits of m mentioned above can be combined arbitrarily.

[0144] It is preferable that m be -0.05 or more and 0.20 or less, more preferable that it be -0.02 or more and 0.10 or less, and particularly preferable that it be 0 or more and 0.06 or less.

[0145] In the composition formula (1), from the perspective of obtaining a lithium secondary battery with high discharge rate characteristics, it is preferable that 0 < m + n ≤ 0.25, more preferable that 0.05 ≤ m + n ≤ 0.20, and particularly preferable that 0.07 ≤ m + n ≤ 0.12.

[0146] In the composition formula (1), n ​​is preferably 0.05 or higher, and more preferably 0.09 or higher. Also, n is preferably 0.20 or lower, and more preferably 0.15 or lower.

[0147] The upper and lower limits of n can be combined arbitrarily. Examples of combinations include n being 0.05 or greater and 0.20 or less, and 0.09 or greater and 0.15 or less.

[0148] For combinations of m and n, it is desirable that -0.02 ≤ m ≤ 0.10 and 0.09 ≤ n ≤ 0.15.

[0149] [D 10 / D 50 ]

[0150] LiMO is, D 10 and D 50 Of D 10 / D 50 It is desirable that the value of is 0.40 or higher and less than 0.60. D 10 / D 50 Silver is more preferably 0.55 or less, and even more preferably 0.54 or less. D 10 / D 50 For silver, 0.43 or higher is more preferable, and 0.44 or higher is even more preferable. D 10 / D 50 The above upper and lower limits may be combined arbitrarily. Examples of combinations include 0.43 or more and 0.55 or less, and 0.44 or more and 0.54 or less.

[0151] D 10 / D 50 LiMO in which the value satisfies the aforementioned specific range has a small proportion of particles with small particle sizes, that is, particles with a large BET specific surface area. In a CAM using LiMO with a small proportion of particles with a large BET specific surface area, it is difficult for the contact area with the electrolyte to increase excessively. For this reason, irreversible reactions are easily suppressed.

[0152] D 10 / D 50 LiMOs in which the value of the above specific range are used as CAMs, so that the contact area with the electrolyte is not excessively increased. For this reason, irreversible reactions are easily suppressed, and the cycle retention rate of the lithium secondary battery can be improved.

[0153] (Layered structure)

[0154] The crystal structure of LiMO is layered, and it is more preferable that it be a hexagonal crystal structure or a monoclinic crystal structure.

[0155] The hexagonal crystal structure is, P3, P31, P32, R3, P-3, R-3, P312, P321, P3112, P3121, P3212, P3221, R32, P3m1, P31m, P3c1, P31c, R3m, R3c, P-31m, P-31c, P-3 m1, P-3c1, R-3m, R-3c, P6, P61, P65, P62, P64, P63, P-6, P6 / m, P63 / m, P622, P6122, P6522, P6222, P6422, P6322, P6㎜, P6cc, P63㎝, P63mc, P-6m2, P-6c2, P-62m, It belongs to any one space group selected from the group consisting of P-62c, P6 / mmm, P6 / mcc, P63 / mcm and P63 / mmc.

[0156] Also, the monoclinic crystal structure belongs to any one space group selected from the group consisting of P2, P21, C2, Pm, Pc, Cm, Cc, P2 / m, P21 / m, C2 / m, P2 / c, P21 / c, and C2 / c.

[0157] Among these, from the perspective of obtaining a lithium secondary battery with a high discharge capacity, it is particularly desirable that the crystal structure be a hexagonal crystal structure belonging to the space group R-3m or a monoclinic crystal structure belonging to C2 / m.

[0158] [Method for Measuring Crystal Structure]

[0159] The crystal structure of LiMO can be measured by observing it using a powder X-ray diffraction measuring device (e.g., Ultima IV manufactured by Rigaku Inc.).

[0160] [α / β]

[0161] For LiMO, it is preferable that the ratio α / β of the crystallite size α obtained from the peak in the range 2θ = 18.7 ± 2° and the crystallite size β obtained from the peak in the range 2θ = 44.6 ± 2° in X-ray diffraction measurements using CuKα rays is 1.71 or higher and 2.50 or lower.

[0162] "Crystallite size α" and "Crystallite size β" are calculated using values ​​measured by powder X-ray diffraction using CuKα rays, as described in [Powder X-ray Diffraction Measurement] above.

[0163] Below, the case where LiMO has a hexagonal crystal structure belonging to space group R-3m will be explained in more detail using drawings.

[0164] FIG. 4 is a schematic diagram of a crystallizer having a crystal structure belonging to space group R-3m. In the crystallizer shown in FIG. 4, the crystallizer size in the direction of the perpendicular to the 003 plane corresponds to the crystallizer size α described above. Also, in the crystallizer shown in FIG. 4, the crystallizer size in the direction of the perpendicular to the 104 plane corresponds to the crystallizer size β.

[0165] As the value of α / β is greater than 1, it indicates that the crystallites are growing anisotropically parallel to the z-axis in Fig. 4, and as the value of α / β approaches 1, it indicates that the crystallites are growing isotropically.

[0166] In LiMOs with α / β greater than 1.0, crystallites grow anisotropically in the z-axis direction with respect to the x-axis or y-axis in Fig. 4.

[0167] Using such LiMO as a CAM can improve battery performance, such as the discharge capacity of a lithium secondary battery.

[0168] For example, a crystallite of LiMO with an α / β of 1.0 or greater is designated as Case 1, and a flat crystallite in which the crystallite has grown anisotropically in a direction parallel to the xy plane of Fig. 4 is designated as Case 2, and the crystallites of Case 1 and Case 2 of the same volume are compared. In this case, the distance to the center of the crystallite of Case 1 is shorter than that of the crystallite of Case 2. Therefore, in the crystallite of Case 1, the movement of lithium ions accompanying charging and discharging is facilitated.

[0169] It is preferable that α / β be 1.71 or higher and 2.50 or lower. It is more preferable that α / β be 1.72 or higher, and even more preferable that 1.73 or higher. It is more preferable that α / β be 2.40 or lower, and even more preferable that 2.30 or lower.

[0170] The upper and lower limits of α / β above may be combined arbitrarily. Examples of combinations include α / β being 1.72 or higher and 2.40 or lower, and 1.73 or higher and 2.30 or lower.

[0171] LiMO satisfying the above specific range for α / β has low resistance to the movement of lithium ions during charging and discharging, so when used as a CAM, it can improve the cycle retention rate of a lithium secondary battery.

[0172] In one aspect of the present embodiment, the precursor and LiMO consist only of primary particles.

[0173] In one aspect of the present embodiment, the precursor and LiMO consist of secondary particles which are aggregates of primary particles and primary particles which exist independently of the secondary particles.

[0174] In one aspect of the present embodiment, the precursor and LiMO consist only of secondary particles that are aggregates of primary particles.

[0175] In one aspect of the present embodiment, the precursor and LiMO are powders.

[0176] <Method for manufacturing a precursor>

[0177] Explain the method for manufacturing the precursor.

[0178] The precursor comprises at least Ni and element M. Examples of precursors include nickel-cobalt-manganese complex hydroxide as a metal complex hydroxide or nickel-cobalt-manganese complex oxide as a metal complex oxide.

[0179] Hereinafter, an embodiment for manufacturing a nickel-cobalt-manganese complex hydroxide is described as an example of a method for manufacturing a precursor.

[0180] The process for manufacturing a precursor involves continuously supplying a metal-containing aqueous solution containing nickel, cobalt, and manganese, a pH adjusting solution, and a complexing agent solution to a reaction apparatus equipped with stirring means and a reaction channel to react them. By doing so, Ni a Co b Mn c A metal complex hydroxide represented by (OH)2 (where a + b + c = 1) is obtained.

[0181] [Each ingredient]

[0182] The metal-containing aqueous solution, pH adjustment solution, and complexing agent solution, which are raw material solutions used in the manufacture of the precursor, are described.

[0183] As for the nickel salt that is the solute of the above nickel salt solution, it is not particularly limited, but, for example, one or more of nickel sulfate, nickel nitrate, nickel chloride, and nickel acetate may be used.

[0184] As the cobalt salt that is the solute of the above cobalt salt solution, for example, one or two or more of cobalt sulfate, cobalt nitrate, cobalt chloride, and cobalt acetate may be used.

[0185] As the manganese salt that is the solute of the above manganese salt solution, for example, one or two or more of manganese sulfate, manganese nitrate, manganese chloride, and manganese acetate may be used.

[0186] The metal salt above is the above Ni a Co b Mn c It is used in a ratio corresponding to the compositional ratio of (OH)2. That is, for each metal salt, the molar ratio of Ni in the solute of the nickel salt solution, Co in the solute of the cobalt salt solution, and Mn in the solute of the manganese salt solution is such that Ni a Co b Mn c Use an amount that satisfies a : b : c corresponding to the composition ratio of (OH)2.

[0187] Also, the solvent for nickel salt solution, cobalt salt solution, and manganese salt solution is water.

[0188] An alkaline aqueous solution is used as a pH adjustment solution. As alkaline aqueous solutions, for example, an aqueous solution of sodium hydroxide or an aqueous solution of potassium hydroxide can be used.

[0189] In addition, the pH value in this specification is defined as the value measured when the temperature of the reactant is 40°C. The pH of the mixture is measured when the temperature of the reactant sampled from the reaction apparatus reaches 40°C.

[0190] If the temperature of the sampled reactant is lower than 40 ℃, the reactant is heated until it reaches 40 ℃, at which point the pH is measured.

[0191] If the temperature of the sampled reactant is higher than 40 ℃, the reactant is cooled until it reaches 40 ℃, at which point the pH is measured.

[0192] A complexing agent solution is a compound capable of forming a complex with nickel ions, cobalt ions, and manganese ions in an aqueous solution. Examples of complexing agents include ammonium ion donors, hydrazine, ethylenediaminetetraacetic acid, nitrileto-tetraacetic acid, uracil-tetraacetic acid, and glycine.

[0193] As ammonium ion sources, ammonium salts such as ammonium hydroxide, ammonium sulfate, ammonium chloride, ammonium carbonate, and ammonium fluoride can be used.

[0194] In addition, during the reaction, the pH value in the reaction vessel is controlled to, for example, within the range of pH 9 or higher and pH 13 or lower, preferably pH 11 or higher and pH 13 or lower.

[0195] [Means of Reaction]

[0196] As a reaction apparatus equipped with stirring means and a reaction channel, for example, a reaction apparatus equipped with a Taylor-type reaction apparatus or a microreactor may be used. In addition, a reaction apparatus such as an overflow type reaction vessel may be used to separate the formed reaction precipitate. Particle size (D 60 , D 50 , D 10 From the perspective of controlling ), it is desirable to use a device with high shear force of the stirring means. Examples of such devices include Taylor-type reactors or microreactors.

[0197] As the reaction apparatus used in the batch co-precipitation method, a reaction vessel without an overflow pipe may be used. Alternatively, a type of apparatus may be used that is equipped with a concentration tank connected to an overflow pipe, and has a mechanism for concentrating the overflowed reaction precipitate into a concentration layer and recirculating it back into the reaction vessel.

[0198] In this embodiment, it is preferable to use a reaction means equipped with a Taylor-type reaction device. As the Taylor-type reaction device, a Taylor vortex continuous stirring reaction device may be preferably used.

[0199] FIG. 2 shows a schematic diagram of an example of a reaction means equipped with a Taylor-type reaction device. The reaction means (60) shown in FIG. 2 is equipped with a raw material liquid storage tank (T1), a raw material liquid storage tank (T2), a raw material liquid storage tank (T3), a transport pump (P1), a transport pump (P2), a transport pump (P3), a heat exchanger (H1), a heat exchanger (H2), a heat exchanger (H3), a Taylor vortex continuous stirring reaction device (40), and a reactant storage tank (50). The Taylor vortex continuous stirring reaction device (40) may be referred to as "reaction device (40)" hereinafter.

[0200] A metal-containing aqueous solution containing, for example, Ni, Co, and Mn is stored in a raw material liquid storage tank (T1). The metal-containing aqueous solution containing Ni, Co, and Mn is transferred from the raw material liquid storage tank (T1) to a reaction device (40) by a transport pump (P1). If it is necessary to adjust the temperature of the metal-containing aqueous solution containing Ni, Co, and Mn, it is adjusted by a heat exchanger (H1).

[0201] For example, a pH adjustment solution is stored in the raw material storage tank (T2). The pH adjustment solution is transferred from the raw material storage tank (T2) to the reaction device (40) by a transport pump (P2). If it is necessary to adjust the temperature of the pH adjustment solution, it is adjusted by a heat exchanger (H2).

[0202] For example, a complexing agent solution is stored in the raw material liquid storage tank (T3). The complexing agent solution is transferred from the raw material liquid storage tank (T3) to the reaction device (40) by a transport pump (P3). If it is necessary to adjust the temperature of the complexing agent solution, it is adjusted by a heat exchanger (H3).

[0203] In addition, the reaction means is not specifically limited to FIG. 2, and, for example, one or more storage tanks and one or more heat exchangers may be used.

[0204] The reactants, in which the metal-containing aqueous solution containing Ni, Co, and Mn, the pH adjustment solution, and the complexing agent solution are reacted in the reaction device (40), are sent from the reaction device (40) to the reactant storage tank (50).

[0205] FIG. 3 shows a schematic cross-sectional view of a reaction device (40). The reaction device (40) is equipped with a cylinder (41) and a stirring means (42). The cylinder (41) is a hollow cylindrical reaction vessel. The stirring means (42) is cylindrical.

[0206] The stirring means (42) is positioned inside the cylinder (41) in a manner that does not come into contact with the cylinder (41). The cylinder (41) and the stirring means (42) form a coaxial double cylinder structure. By rotating the stirring means (42) around the axis of rotation, the fluid present in the reaction channel (S) is stirred.

[0207] One or more inlet ports for introducing raw material liquid are formed in the cylinder (41).

[0208] The cylinder (41) has three inlets (43a, 43b, and 43c) at one end. The cylinder (41) also has an outlet (44) for discharging reactants at the other end.

[0209] For example, the inlet port (43a) is connected to the raw material storage tank (T1), the inlet port (43b) is connected to the raw material storage tank (T2), and the inlet port (43c) is connected to the raw material storage tank (T3), each via a transport pump and a heat exchanger.

[0210] When raw material liquid is introduced into the reaction device (40) from the inlet port (43a, 43b and 43c), each raw material liquid is mixed and reacted in the reaction channel (S) near the inlet port, and the resulting reaction product is discharged from the outlet port (44).

[0211] Each raw material liquid introduced from the inlet is mixed and reacted in the reaction channel (S) and becomes a reactant.

[0212] In the reaction channel (S), which is the gap between the cylinder (41) and the stirring means (42), a reaction proceeds. When the cylinder (41) is fixed and only the stirring means (42) is rotated by a driving unit not shown, a flow of fluid is generated in the reaction channel (S) that rotates along the direction of rotation of the stirring means (42) while drawing a spiral due to centrifugal force and Coriolis force. The "fluid" referred to here means a mixed liquid in which each raw material liquid is mixed and a reaction product in which each raw material liquid is mixed and reacted.

[0213] Thus, the fluid forms a plurality of annular vortices (U) in pairs, consisting of a first annular vortex (U1) and a second annular vortex (U2), which rotate regularly and in opposite directions along the stirring means (42). The annular vortex (U) is called a Taylor vortex. The annular vortex (U) does not disperse in the axial direction of the stirring means (42) but moves parallel.

[0214] Due to the spiral flow of the Taylor vortex, the fluid in the reaction channel (S) is efficiently mixed and heat is also efficiently transferred.

[0215] A neutralization reaction occurs near the inlet (43a, 43b and 43c), and a metal complex hydroxide is produced. After the metal complex hydroxide is produced, while the fluid is discharged from the outlet (44), crystals of the metal complex hydroxide grow in the reaction channel (S).

[0216] It is desirable to control the temperature near the inlet of each raw material liquid. Specifically, for example, the temperature of each raw material liquid is measured at the temperature measurement locations indicated by the symbols Ma, Mb, and Mc in FIG. 3.

[0217] The temperature of each raw material liquid is adjusted under the condition that the difference between the maximum and minimum temperatures at the temperature measurement location is 1.5 ℃ or less.

[0218] The maximum and minimum temperatures are the maximum and minimum temperatures of each raw material solution at the temperature measurement location. By adjusting the difference between the maximum and minimum temperatures to 1.5 ℃ or less, the reaction immediately after each raw material solution is introduced from the inlet into the reaction channel (S) can be stabilized, thus the precursor D 60 / D 10 The value of and the BET specific surface area can be controlled within the range of this embodiment.

[0219] The temperature of each raw material solution is adjusted, for example, by the heat exchangers (H1, H2, and H3) shown in FIG. 2. The raw material solution for temperature adjustment is not particularly limited and may be any of the nickel-cobalt-manganese metal-containing aqueous solution, pH adjustment solution, or complexing agent solution. In this embodiment, since the reaction is initiated by adding the pH adjustment solution, it is preferable to adjust the temperature of the pH adjustment solution first.

[0220] It is preferable to rotate the stirring means (42) under conditions where the Taylor number satisfies 60 or more and 20,000 or less. By adjusting the Taylor number, the D of the precursor 10 / D 50The value of can be controlled. The Taylor number Ta is calculated by the following formula.

[0221] [Mathematical Formula 1]

[0222]

[0223] (R i θ is the outer diameter (mm) of the stirring means (42), ω is the rotational speed (rad / s) of the stirring means (42), d is the distance (mm) between the inner wall surface of the cylinder (41) and the stirring means (42), μ is the viscosity of the fluid (Pa·s), and ρ is the density of the fluid (kg / m³))

[0224] The reaction device (40) adjusts the gap width (d1), which is the gap between the inner wall surface of the cylinder (41) and the stirring means (42), thereby controlling the D of the precursor 60 / D 10 The value of and the BET specific surface area can be controlled. The D of the precursor 60 / D 10 In order to control the value and BET specific surface area within the range of the present embodiment, it is preferable to adjust the gap width (d1) to a range of 2 mm or more and 20 mm or less.

[0225] The rotational speed of the stirring means (42) is preferably 10 rad / s or more, and more preferably 25 rad / s or more.

[0226] For example, the TVF-1 type manufactured by Chipton Co., Ltd. can be used as a Taylor vortex continuous stirring reaction device.

[0227] After the above reaction, the obtained reaction product is washed with water and then dried to obtain a metal complex compound. A nickel-cobalt-manganese complex hydroxide is obtained as a nickel-cobalt-manganese complex compound. In addition, if impurities originating from the reaction product remain when the reaction product is washed with water, the reaction product may be washed with a weakly acidic aqueous solution or an alkaline aqueous solution containing sodium hydroxide or potassium hydroxide.

[0228] If significant cracking or defects occur in the particles of the metal composite compound during the above washing or drying process, classification may be performed. As a classification method, for example, wind classification or screen sorting using a sieve may be used.

[0229] In addition, in the above example, a nickel-cobalt-manganese complex hydroxide is prepared, but a nickel-cobalt-manganese complex oxide may also be prepared.

[0230] For example, a nickel-cobalt-manganese complex oxide can be prepared by calcining a nickel-cobalt-manganese complex hydroxide in an oxygen-containing atmosphere. The maximum holding temperature may be, for example, in the range of 350 °C or higher and 800 °C or lower. During the calcination time, the total time from the start of the heating process to the end of the temperature holding process may be, for example, in the range of 1 hour or higher and 30 hours or lower. The heating rate of the heating process to reach the maximum holding temperature may be, for example, in the range of 100 °C / hour or higher. In addition, air, oxygen, nitrogen, argon, or a mixture thereof may be used as the atmosphere for calcination.

[0231] The maximum holding temperature refers to the maximum temperature of the atmosphere within the kiln during the firing process, and signifies the firing temperature during the firing process. In the case of this firing process having multiple heating processes, the maximum holding temperature refers to the maximum temperature during each heating process.

[0232] The heating rate is calculated from the time from when heating is started in the firing apparatus until the maximum holding temperature is reached, and the temperature difference from the temperature at the start of heating in the firing furnace of the firing apparatus to the maximum holding temperature.

[0233] <Method for Manufacturing Lithium Metal Composite Oxide>

[0234] A method for manufacturing LiMO comprising a mixing process for mixing a precursor obtained by the above-described method for manufacturing a precursor with a lithium compound, and a calcination process for calcining the obtained mixture. By using the above-described precursor, D 60 / D 10 LiMO can be manufactured in which the BET specific surface area is within the range of this embodiment.

[0235] [Mixing Process]

[0236] This process is a process of mixing a precursor and a lithium compound to obtain a mixture.

[0237] The lithium compound may be used as one of lithium carbonate, lithium nitrate, lithium acetate, lithium hydroxide, lithium oxide, lithium chloride, and lithium fluoride, or as a mixture of two or more. Among these, either or both of lithium hydroxide and lithium carbonate are preferred.

[0238] The method of mixing the precursor and the lithium compound is explained.

[0239] The precursor and the lithium compound are mixed taking into account the compositional ratio of the final product. For example, when using a nickel-cobalt-manganese metal complex compound, the nickel-cobalt-manganese complex compound and the lithium compound are Li[Li m (Ni a Co b Mn c ) 1-m It is used in a ratio corresponding to the composition ratio of ]O2(a + b + c = 1). Also, in the case of the final product LiMO, if Li is in excess (the molar ratio of Li is greater than 1), it is mixed in a ratio such that the molar ratio of Li contained in the lithium compound and the metal element contained in the metal complex compound exceeds 1.

[0240] A lithium-nickel-cobalt-manganese composite oxide is obtained by calcining a mixture of a nickel-cobalt-manganese composite compound and a lithium compound. Additionally, for calcination, dry air, an oxygen-containing atmosphere, an inert atmosphere, etc., are used depending on the desired composition, and multiple heating processes are performed if necessary.

[0241] In the present embodiment, calcination of the mixture may be performed in the presence of an inert flux. By performing calcination in the presence of an inert flux, the reaction of the mixture can be accelerated. The inert flux may remain in the LiMO after calcination, or it may be removed by washing with water or alcohol after calcination. In the present embodiment, it is preferable to wash the LiMO after calcination using water or alcohol.

[0242] By adjusting the holding temperature during calcination, the particle size of the obtained LiMO can be controlled.

[0243] The firing process may be a single firing step or may have multiple firing steps.

[0244] In cases where there are multiple firing stages, the process of firing at the highest temperature is designated as the main firing. Prior to the main firing, a preliminary firing at a temperature lower than that of the main firing may be performed. Additionally, after the main firing, a subsequent firing at a temperature lower than that of the main firing may be performed.

[0245] The calcination temperature (maximum holding temperature) of the present invention is preferably 600°C or higher, more preferably 650°C or higher, and particularly preferably 700°C or higher, from the perspective of promoting the growth of LiMO particles. In addition, from the perspective of preventing the formation of cracks in LiMO particles and maintaining the strength of LiMO particles, it is preferably 1200°C or lower, more preferably 1100°C or lower, and particularly preferably 1000°C or lower.

[0246] The upper and lower limits of the maximum holding temperature for this firing can be combined arbitrarily.

[0247] Examples of combinations include 600°C or higher and 1200°C or lower, 650°C or higher and 1100°C or lower, and 700°C or higher and 1000°C or lower.

[0248] The firing temperature of the pre-firing or post-firing may be lower than the firing temperature of the main firing, for example, in the range of 350°C or higher and 700°C or lower.

[0249] As the maximum holding temperature increases, the particle size of LiMO tends to increase, and the BET specific surface area tends to decrease. By adjusting the maximum holding temperature, the particle size, BET specific surface area, and α / β values ​​of LiMO can be adjusted. The holding temperature during calcination can be appropriately adjusted according to the type of transition metal element used, the precipitating agent, and the type and amount of inert flux.

[0250] The setting of the holding temperature should be done by considering the melting point of the inert flux described below, and it is preferable to perform it in the range of minus 200°C or higher and plus 200°C or lower of the melting point of the inert flux.

[0251] In addition, the holding time at the above holding temperature may be 0.1 hours or more and 20 hours or less, and preferably 0.5 hours or more and 10 hours or less. The heating rate to the above holding temperature is typically 50 ℃ / hour or more and 400 ℃ / hour or less, and the cooling rate from the above holding temperature to room temperature is typically 10 ℃ / hour or more and 400 ℃ / hour or less. In addition, as the atmosphere for firing, air, oxygen, nitrogen, argon, or a mixture thereof may be used.

[0252] The LiMO obtained by calcination is appropriately classified after grinding to become a CAM applicable to lithium secondary batteries.

[0253] The inert flux is not particularly limited as long as it is difficult to react with the mixture during calcination. In the present embodiment, examples include one or more selected from the group consisting of a fluoride of one or more elements selected from the group consisting of Na, K, Rb, Cs, Ca, Mg, Sr, and Ba (hereinafter referred to as "A"), a chloride of A, a carbonate of A, a sulfate of A, a nitrate of A, a phosphate of A, a hydroxide of A, a molybdate of A, and a tungstate of A.

[0254] Examples of fluorides of A include NaF (melting point: 993 ℃), KF (melting point: 858 ℃), RbF (melting point: 795 ℃), CsF (melting point: 682 ℃), CaF2 (melting point: 1402 ℃), MgF2 (melting point: 1263 ℃), SrF2 (melting point: 1473 ℃) and BaF2 (melting point: 1355 ℃).

[0255] Examples of chlorides of A include NaCl (melting point: 801 °C), KCl (melting point: 770 °C), RbCl (melting point: 718 °C), CsCl (melting point: 645 °C), CaCl2 (melting point: 782 °C), MgCl2 (melting point: 714 °C), SrCl2 (melting point: 857 °C) and BaCl2 (melting point: 963 °C).

[0256] Examples of carbonates of A include Na2CO3 (melting point: 854 ℃), K2CO3 (melting point: 899 ℃), Rb2CO3 (melting point: 837 ℃), Cs2CO3 (melting point: 793 ℃), CaCO3 (melting point: 825 ℃), MgCO3 (melting point: 990 ℃), SrCO3 (melting point: 1497 ℃) and BaCO3 (melting point: 1380 ℃).

[0257] Examples of sulfates of A include Na2SO4 (melting point: 884 ℃), K2SO4 (melting point: 1069 ℃), Rb2SO4 (melting point: 1066 ℃), Cs2SO4 (melting point: 1005 ℃), CaSO4 (melting point: 1460 ℃), MgSO4 (melting point: 1137 ℃), SrSO4 (melting point: 1605 ℃) and BaSO4 (melting point: 1580 ℃).

[0258] Examples of nitrates of A include NaNO3 (melting point: 310 ℃), KNO3 (melting point: 337 ℃), RbNO3 (melting point: 316 ℃), CsNO3 (melting point: 417 ℃), Ca(NO3)2 (melting point: 561 ℃), Mg(NO3)2, Sr(NO3)2 (melting point: 645 ℃), and Ba(NO3)2 (melting point: 596 ℃).

[0259] Examples of phosphates of A include Na3PO4, K3PO4 (melting point: 1340 ℃), Rb3PO4, Cs3PO4, Ca3(PO4)2, Mg3(PO4)2 (melting point: 1184 ℃), Sr3(PO4)2 (melting point: 1727 ℃) and Ba3(PO4)2 (melting point: 1767 ℃).

[0260] Examples of hydroxides of A include NaOH (melting point: 318 ℃), KOH (melting point: 360 ℃), RbOH (melting point: 301 ℃), CsOH (melting point: 272 ℃), Ca(OH)2 (melting point: 408 ℃), Mg(OH)2 (melting point: 350 ℃), Sr(OH)2 (melting point: 375 ℃) and Ba(OH)2 (melting point: 853 ℃).

[0261] Examples of molybdates of A include Na2MoO4 (melting point: 698 ℃), K2MoO4 (melting point: 919 ℃), Rb2MoO4 (melting point: 958 ℃), Cs2MoO4 (melting point: 956 ℃), CaMoO4 (melting point: 1520 ℃), MgMoO4 (melting point: 1060 ℃), SrMoO4 ​​(melting point: 1040 ℃) and BaMoO4 (melting point: 1460 ℃).

[0262] Examples of tungstates of A include Na2WO4 (melting point: 687 °C), K2WO4, Rb2WO4, Cs2WO4, CaWO4, MgWO4, SrWO4, and BaWO4.

[0263] Two or more of these inert fluxes may be used. When two or more are used, the melting point of the entire inert flux may be lowered.

[0264] In addition, among these inert fluxes, for obtaining LiMO with higher crystallinity, one or more salts selected from the group consisting of carbonates of A, sulfates of A and chlorides of A are preferred.

[0265] Also, it is preferable that A be either or both of Na and K.

[0266] That is, among the above inert fluxes, particularly preferred inert fluxes are preferably one or more selected from the group consisting of NaCl, KCl, Na2CO3, K2CO3, Na2SO4, and K2SO4, and it is more preferable to use either or both of K2SO4 and Na2SO4.

[0267] The amount of inert flux present during calcination can be appropriately selected. For example, the amount of inert flux present during calcination is preferably 0.1 parts by mass or more per 100 parts by mass of the lithium compound, and more preferably 1 part by mass or more. In addition, if it is necessary to promote particle growth, an inert flux other than the aforementioned inert flux may be used together. Examples of inert fluxes used in this case include ammonium salts such as NH4Cl and NH4F.

[0268] <CAM>

[0269] The CAM of the present embodiment contains the LiMO of the present embodiment. The CAM of the present embodiment may contain a LiMO other than the LiMO of the present embodiment.

[0270] <Lithium Secondary Battery>

[0271] Next, while describing the composition of the lithium secondary battery, the CAM using LiMO of the present embodiment, the positive electrode using the CAM, and the lithium secondary battery having the positive electrode will be described.

[0272] CAM is preferably composed of the LiMO of the above embodiment, but may contain other components within a range that does not impede the effects of the present invention.

[0273] An example of a lithium secondary battery has a positive electrode and a negative electrode, a separator placed between the positive electrode and the negative electrode, and an electrolyte placed between the positive electrode and the negative electrode.

[0274] FIGS. 1a and 1b are schematic diagrams showing an example of a lithium secondary battery of the present embodiment. The cylindrical lithium secondary battery (10) of the present embodiment is manufactured as follows.

[0275] First, as shown in FIG. 1a, a pair of separators (1) having a strip shape, a strip-shaped positive electrode (2) having a positive electrode lead (21) at one end, and a strip-shaped negative electrode (3) having a negative electrode lead (31) at one end are stacked in the order of separator (1), positive electrode (2), separator (1), and negative electrode (3) and wound to form an electrode group (4).

[0276] Next, as shown in FIG. 1b, an electrode group (4) and an insulator not shown are placed in a battery can (5), the bottom of the can is sealed, and an electrolyte (6) is impregnated into the electrode group (4) to place the electrolyte between the positive electrode (2) and the negative electrode (3). Additionally, a lithium secondary battery (10) can be manufactured by sealing the top of the battery can (5) with a top insulator (7) and a sealing body (8).

[0277] For example, the shape of the electrode group (4) can be a columnar shape in which the cross-sectional shape when the electrode group (4) is cut perpendicular to the axis of the winding is a circle, an ellipse, a rectangle, or a rectangle with rounded corners.

[0278] In addition, the shape of the lithium secondary battery having such an electrode group (4) may be adopted from the shape specified in IEC60086, a battery standard set by the International Electrotechnical Commission (IEC), or JIS C 8500. For example, cylindrical or prismatic shapes may be used.

[0279] In addition, the lithium secondary battery is not limited to the above-mentioned wound configuration, but may also have a stacked configuration in which a stacked structure of a positive electrode, a separator, a negative electrode, and a separator is repeatedly stacked. Examples of stacked lithium secondary batteries include so-called coin-type batteries, button-type batteries, and paper-type (or sheet-type) batteries.

[0280] Below, each component will be explained in turn.

[0281] (Straight play)

[0282] The positive electrode of the present embodiment can be manufactured by first preparing a positive electrode mixture comprising a CAM, a conductive material, and a binder, and then supporting the positive electrode mixture on a positive electrode current collector.

[0283] (Challenge)

[0284] Carbon materials can be used as the conductive material for the positive electrode. Examples of carbon materials include graphite powder, carbon black (e.g., acetylene black), and fibrous carbon materials.

[0285] The ratio of the conductive material in the positive electrode composite is preferably 5 parts by mass or more and 20 parts by mass or less per 100 parts by mass of CAM. When fibrous carbon materials such as graphitized carbon fibers or carbon nanotubes are used as the conductive material, this ratio can also be lowered.

[0286] (bookbinder)

[0287] As a binder for the positive electrode, a thermoplastic resin may be used. Examples of such thermoplastic resins include polyimide resin; polyvinylidene fluoride (hereinafter referred to as PVdF); fluoropolymer resins such as polytetrafluoroethylene; polyolefin resins such as polyethylene and polypropylene; and resins described in WO2019 / 098384A1 or US2020 / 0274158A1.

[0288] These thermoplastic resins may be used by mixing two or more types. Fluoropolymer resin and polyolefin resin are used as binders, and by setting the ratio of fluoropolymer resin to the total positive electrode composite to 1 mass% or more and 10 mass% or less, and the ratio of polyolefin resin to 0.1 mass% or more and 2 mass% or less, a positive electrode composite with high adhesion to the positive electrode current collector and high bonding strength within the positive electrode composite can be obtained.

[0289] (The entire drama house)

[0290] As a positive electrode current collector, a strip-shaped member made of a metal material such as aluminum, nickel, or stainless steel can be used. Among these, it is preferable to use Al as the forming material and process it into a thin film shape, as it is easy to process and inexpensive.

[0291] One method for supporting a positive electrode composite on a positive electrode current collector is to press-mold the positive electrode composite onto the positive electrode current collector. Alternatively, the positive electrode composite may be supported on the positive electrode current collector by using an organic solvent to form a paste of the positive electrode composite, applying the resulting paste of the positive electrode composite to at least one side of the positive electrode current collector, drying it, and then pressing it to fix it.

[0292] When forming a positive electrode composite into a paste, organic solvents that can be used include amine-based solvents such as N,N-dimethylaminopropylamine and diethylenetriamine; ether-based solvents such as tetrahydrofuran; ketone-based solvents such as methyl ethyl ketone; ester-based solvents such as methyl acetate; and amide-based solvents such as dimethylacetamide and N-methyl-2-pyrrolidone (hereinafter referred to as NMP).

[0293] Methods for applying a positive electrode paste to a positive electrode current collector include, for example, slit die coating, screen coating, curtain coating, knife coating, gravure coating, and electrostatic spraying.

[0294] A positive electrode can be manufactured by the method described above.

[0295] (Polar)

[0296] The negative electrode of a lithium secondary battery can be formed by enabling doping and undoping of lithium ions at a lower potential than that of the positive electrode, and may include an electrode formed by a negative electrode composite containing a negative electrode active material supported on a negative electrode current collector, and an electrode formed by a negative electrode active material alone.

[0297] (Negative electrode active material)

[0298] Examples of negative electrode active materials include carbon materials, chalcogen compounds (oxides, sulfides, etc.), nitrides, metals, or alloys, which are materials capable of doping and undoping lithium ions at a potential lower than that of the positive electrode.

[0299] Carbon materials that can be used as negative electrode active materials include graphite such as natural graphite and artificial graphite, coke, carbon black, pyrolytic carbon, carbon fiber, and calcined organic polymer compounds.

[0300] Oxides usable as negative electrode active materials include SiO2 and SiO2, etc., of the formula SiO2 x Oxides of silicon represented by (where x is a defined real number); SnO2 and SnO2, etc. x Tin oxide represented as (where x is a defined real number); Li4Ti5O 12 Examples include metal complex oxides containing Li and Ti or V, such as LiVO2.

[0301] In addition, metals that can be used as negative electrode active materials include lithium metal, silicon metal, and tin metal.

[0302] As a material that can be used as a negative electrode active material, the material described in WO2019 / 098384A1 or US2020 / 0274158A1 may be used.

[0303] In addition, metals that can be used as negative electrode active materials include lithium metal, silicon metal, and tin metal.

[0304] Alloys that can be used as negative electrode active materials include lithium alloys such as Li-Al, Li-Ni, Li-Si, Li-Sn, Li-Sn-Ni; silicon alloys such as Si-Zn; tin alloys such as Sn-Mn, Sn-Co, Sn-Ni, Sn-Cu, Sn-La; and alloys such as Cu2Sb, La3Ni2Sn7.

[0305] These metals or alloys, for example, are processed into thin sheets and used primarily alone as electrodes.

[0306] Among the above negative electrode active materials, carbon materials with graphite as the main component, such as natural graphite or synthetic graphite, are preferably used for reasons such as the negative electrode potential remaining almost unchanged from the uncharged state to the fully charged state during charging (good potential flatness), the average discharge potential being low, and the capacity retention rate being high when subjected to repeated charge-discharge (good cycle characteristics). The shape of the carbon material may be any of the following: flake-like, such as natural graphite; spherical, such as mesocarbon micro beads; fibrous, such as graphitized carbon fibers; or aggregates of fine powder.

[0307] The above negative electrode composite may contain a binder as needed. Examples of binders include thermoplastic resins, specifically PVdF, thermoplastic polyimide, carboxymethylcellulose (hereinafter referred to as CMC), styrene-butadiene rubber (hereinafter referred to as SBR), polyethylene, and polypropylene.

[0308] (The entire Bu-geuk house)

[0309] As a negative electrode current collector for the negative electrode, a strip-shaped member made of a metal material such as copper, nickel, or stainless steel can be used as the forming material. Among these, it is preferable to use Cu as the forming material and process it into a thin film, as it is difficult to form an alloy with lithium and is easy to process.

[0310] Methods for supporting a negative electrode composite on such a negative electrode current collector include, as with the positive electrode, a method by pressure molding, or a method of forming a paste using a solvent, applying it onto the negative electrode current collector, drying it, and then pressing it.

[0311] (Separator)

[0312] As a separator for a lithium secondary battery, materials having the form of a porous membrane, nonwoven fabric, woven fabric, etc., made of materials such as polyolefin resins like polyethylene and polypropylene, fluoropolymers, and nitrogen-containing aromatic polymers, may be used. In addition, a separator may be formed by using two or more of these materials, or by stacking these materials to form a separator. Also, a separator described in JP-A-2000-030686 or US20090111025A1 may be used.

[0313] In order to allow the electrolyte to pass through well when using the battery (during charging and discharging), the separator preferably has a permeability resistance according to the Gullley method specified in JIS P 8117 of 50 sec / 100 cc or more and 300 sec / 100 cc or less, and more preferably 50 sec / 100 cc or more and 200 sec / 100 cc or less.

[0314] In addition, the porosity of the separator is preferably 30 volume% or more and 80 volume% or less, and more preferably 40 volume% or more and 70 volume% or less. The separator may be a stack of separators with different porosities.

[0315] (Electrolyte)

[0316] The electrolyte of a lithium secondary battery contains an electrolyte and an organic solvent.

[0317] Examples of electrolytes included in the electrolyte include lithium salts such as LiClO4, LiPF6, and LiBF4, and a mixture of two or more of these may be used. Additionally, an electrolyte described in WO2019 / 098384A1 or US2020 / 0274158A1 may be used. Among these, it is preferable to use an electrolyte that includes at least one selected from the group consisting of fluorine-containing LiPF6, LiAsF6, LiSbF6, LiBF4, LiCF3SO3, LiN(SO2CF3)2, and LiC(SO2CF3)3.

[0318] In addition, as an organic solvent included in the above electrolyte, for example, propylene carbonate, ethylene carbonate, dimethyl carbonate, diethyl carbonate, ethylmethyl carbonate, or an organic solvent described in WO2019 / 098384A1 or US2020 / 0274158A1 may be used.

[0319] As for organic solvents, it is preferable to use a mixture of two or more of these, and a mixed solvent of cyclic carbonates and non-cyclic carbonates, and a mixed solvent of cyclic carbonates and ethers are even more preferable. As for the mixed solvent of cyclic carbonates and non-cyclic carbonates, a mixed solvent containing ethylene carbonate, dimethyl carbonate, and ethyl methyl carbonate is preferred.

[0320] In addition, as the safety of the resulting lithium secondary battery is enhanced, it is preferable to use an electrolyte containing a lithium salt containing fluorine, such as LiPF6, and an organic solvent having a fluorine substituent.

[0321] Since the CAM with the above configuration uses the LiMO of the present embodiment, it can improve the cycle retention rate of the lithium secondary battery using the CAM.

[0322] In addition, the positive electrode with the above configuration can improve the cycle retention rate of the lithium secondary battery because it has the CAM with the configuration described above.

[0323] In addition, a lithium secondary battery with the above configuration becomes a secondary battery with a high cycle retention rate because it has the positive electrode described above.

[0324] All-solid-state lithium-ion secondary battery

[0325] Next, while describing the composition of an all-solid-state lithium-ion secondary battery, a positive electrode using the LiMO of the present embodiment as a CAM of an all-solid-state lithium-ion secondary battery, and an all-solid-state lithium-ion secondary battery having said positive electrode will be described.

[0326] FIGS. 5 and 6 are schematic diagrams illustrating an example of an all-solid-state lithium-ion secondary battery. FIG. 5 is a schematic diagram illustrating a laminated structure provided by an all-solid-state lithium-ion secondary battery. FIG. 6 is a schematic diagram illustrating the overall configuration of an all-solid-state lithium-ion secondary battery.

[0327] The all-solid-state lithium-ion secondary battery (1000) has a laminate (100) having a positive electrode (110), a negative electrode (120), and a solid electrolyte layer (130), and an outer body (200) that accommodates the laminate (100). Additionally, the all-solid-state lithium secondary battery (1000) may have 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 a bipolar structure, the structure described in JP-A-2004-95400 may be cited.

[0328] The materials constituting each component will be described later.

[0329] The laminate (100) may have an external terminal (113) connected to a positive electrode current collector (112) and an external terminal (123) connected to a negative electrode current collector (122).

[0330] In the laminate (100), the positive electrode (110) and the negative electrode (120) are held together by a solid electrolyte layer (130) so as not to short-circuit each other. Additionally, the all-solid-state lithium-ion secondary battery (1000) may have a separator between the positive electrode (110) and the negative electrode (120), such as one used in conventional liquid-based lithium-ion secondary batteries, to prevent short-circuiting between the positive electrode (110) and the negative electrode (120).

[0331] The all-solid-state lithium-ion secondary battery (1000) has an insulator not shown that insulates the laminate (100) and the outer body (200), or an encapsulator not shown that encapsulates the opening (200a) of the outer body (200).

[0332] The outer body (200) may be a container formed from a metal material with high corrosion resistance, such as aluminum, stainless steel, or nickel-plated steel. Alternatively, a container may be used in which a laminate film with corrosion resistance treatment applied to at least one surface is processed into a pocket shape.

[0333] The shapes of the all-solid-state lithium-ion secondary battery (1000) include, for example, coin type, button type, paper type (or sheet type), cylindrical type, prismatic type, etc.

[0334] The all-solid-state lithium-ion secondary battery (1000) is illustrated as having one laminate (100), but is not limited thereto. The all-solid-state lithium-ion secondary battery (1000) may be configured such that the laminate (100) is a unit cell and a plurality of unit cells (laminated (100)) are sealed inside an outer body (200).

[0335] Below, each component will be explained in turn.

[0336] (Straight play)

[0337] The positive electrode (110) has a positive electrode active material layer (111) and a positive electrode current collector (112).

[0338] The positive electrode active material layer (111) includes CAM. Also, the positive electrode active material layer (111) may include a solid electrolyte, a conductive material, and a binder.

[0339] (Solid electrolyte)

[0340] As a solid electrolyte included in the positive electrode active material layer (111), a solid electrolyte used in known all-solid-state batteries that has lithium ion conductivity may be employed. Examples of such solid electrolytes include inorganic electrolytes and organic electrolytes. Examples of inorganic electrolytes include oxide-based solid electrolytes, sulfide-based solid electrolytes, and hydride-based solid electrolytes. Examples of organic electrolytes include polymer-based solid electrolytes. Examples of each electrolyte include compounds described in WO2020 / 208872A1, US2016 / 0233510A1, US2012 / 0251871A1, and US2018 / 0159169A1, and examples include the following compounds.

[0341] (Oxide-based solid electrolyte)

[0342] Examples of oxide-based solid electrolytes include perovskite-type oxides, NASICON-type oxides, LISICON-type oxides, and garnet-type oxides. Specific examples of each oxide include compounds described in WO2020 / 208872A1, US2016 / 0233510A1, and US2020 / 0259213A1.

[0343] As for garnet-type oxides, Li7La3Zr2O 12 Examples include Li-La-Zr system oxides such as (LLZ).

[0344] Oxide-based solid electrolytes may be crystalline or amorphous materials. Examples of amorphous solid electrolytes include Li-BO compounds such as Li3BO3, Li2B4O7, and LiBO2. It is preferable that oxide-based solid electrolytes include amorphous materials.

[0345] (Sulride-based solid electrolyte)

[0346] Sulfide-based solid electrolytes include Li2S-P2S5 compounds, Li2S-SiS2 compounds, Li2S-GeS2 compounds, Li2S-B2S3 compounds, LiI-Si2S-P2S5 compounds, LiI-Li2S-P2O5 compounds, LiI-Li3PO4-P2S5 compounds, and Li 10 GeP2S 12 You can lift the back.

[0347] In addition, in this specification, the expression "system compound" referring to a sulfide-based solid electrolyte refers to "Li2S" and "P2S" listed before "system compound". 5」 It is used as a general term for solid electrolytes that mainly contain raw materials such as Li2S and P2S5. For example, Li2S-P2S5-based compounds include solid electrolytes that contain Li2S and P2S5 and other raw materials. In addition, Li2S-P2S5-based compounds also include solid electrolytes with different mixing ratios of Li2S and P2S5.

[0348] Examples of Li2S-P2S5-based compounds include Li2S-P2S5, Li2S-P2S5-LiI, Li2S-P2S5-LiCl, Li2S-P2S5-LiBr, Li2S-P2S5-LiI-LiBr, etc.

[0349] Examples of Li2S-SiS2-based compounds include Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, and Li2S-SiS2-P2S5-LiCl.

[0350] Examples of Li2S-P2S5-based compounds include Li2S-P2S5, Li2S-P2S5-LiI, Li2S-P2S5-LiCl, Li2S-P2S5-LiBr, Li2S-P2S5-LiI-LiBr, etc.

[0351] Examples of Li2S-SiS2-based compounds include Li2S-SiS2, Li2S-SiS2-LiI, Li2S-SiS2-LiBr, Li2S-SiS2-LiCl, Li2S-SiS2-B2S3-LiI, Li2S-SiS2-P2S5-LiI, and Li2S-SiS2-P2S5-LiCl.

[0352] Examples of Li2S-GeS2-based compounds include Li2S-GeS2 and Li2S-GeS2-P2S5.

[0353] Sulfide-based solid electrolytes may be crystalline materials or amorphous materials. It is preferable that sulfide-based solid electrolytes include amorphous materials.

[0354] Two or more types of solid electrolytes may be used in combination to the extent that they do not impede the effects of the invention.

[0355] (Challenge material and binder)

[0356] As the conductive material of the positive electrode active material layer (111), the material described in the above description (conductive material) can be used. Also, regarding the ratio of the conductive material in the positive electrode composite, the ratio described in the above description (conductive material) can be applied in the same way. Also, as the binder of the positive electrode, the material described in the above description (binder) can be used.

[0357] (The entire drama house)

[0358] For the positive electrode current collector (112) of the positive electrode (110), the material described in the above description (positive electrode current collector) can be used.

[0359] One method of supporting the positive electrode active material layer (111) on the positive electrode current collector (112) is to press-form the positive electrode active material layer (111) on the positive electrode current collector (112). A cold press or a hot press can be used for press-forming.

[0360] In addition, a mixture of a positive electrode active material, a solid electrolyte, a conductive material, and a binder may be paste-formed into a positive electrode composite using an organic solvent, and the resulting positive electrode composite may be applied to at least one surface of a positive electrode current collector (112), dried, and fixed by pressing, thereby allowing a positive electrode active material layer (111) to be supported on the positive electrode current collector (112).

[0361] In addition, a mixture of CAM, a solid electrolyte, and a conductive material may be paste-formed using an organic solvent to form a positive electrode composite, and the resulting positive electrode composite may be applied to at least one surface of a positive electrode current collector (112), dried, and sintered to support a positive electrode active material layer (111) on the positive electrode current collector (112).

[0362] As for the organic solvent that can be used for the positive electrode composite, the same organic solvent that can be used when the positive electrode composite described in the above description (positive electrode current collector) is made into a paste can be used.

[0363] Methods for applying the positive electrode mixture to the positive electrode current collector (112) include, for example, slit die coating method, screen coating method, curtain coating method, knife coating method and gravure coating method and electrostatic spray method.

[0364] By the method described above, a positive electrode (110) can be manufactured.

[0365] (Polar)

[0366] 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) includes a negative electrode active material. Additionally, the negative electrode active material layer (121) may include a solid electrolyte and a conductive material. The negative electrode active material, negative electrode current collector, solid electrolyte, conductive material, and binder may be those described above.

[0367] (Solid electrolyte layer)

[0368] The solid electrolyte layer (130) has the solid electrolyte described above.

[0369] 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 positive electrode (110) described above by sputtering.

[0370] Additionally, the solid electrolyte layer (130) can be formed by applying a paste-like mixture containing a solid electrolyte to the surface of the positive electrode active material layer (111) of the positive electrode (110) described above, and drying it. After drying, the solid electrolyte layer (130) may be formed by press molding and further applying pressure by cold isostatic pressing (CIP).

[0371] The laminate (100) can be manufactured by laminating a negative electrode (120) in such a manner that the negative electrode electrolyte layer (121) contacts the surface of the solid electrolyte layer (130) using a known method with respect to the solid electrolyte layer (130) formed on the positive electrode (110) as described above.

[0372] According to the positive electrode with the above configuration, the cycle retention rate of the all-solid-state lithium-ion battery can be improved because it has the CAM described above.

[0373] The present invention further includes the following embodiments.

[0374]

[13] A method for manufacturing a precursor for a lithium secondary battery positive electrode active material, comprising the following processes (A), (B), (C) and (D).

[0375] Process (A): A process for preparing a reaction means comprising a cylinder having a hollow interior, a stirring means disposed inside the cylinder and isolated from the inner wall surface of the cylinder, and one or more raw material liquid storage tanks for storing raw material liquid. wherein the cylinder and the stirring means form a coaxial double cylindrical structure and a reaction flow path is provided between the cylinder and the stirring means.

[0376] Process (B): A process of filling the above raw material liquid storage tank with a metal-containing aqueous solution, a pH adjustment solution, and a complexing agent solution, respectively.

[0377] Process (C): A process for adjusting the difference between the maximum and minimum temperatures to 1.5°C or less in the vicinity of the inlet to the reaction channel of the metal-containing aqueous solution, the pH adjusting solution, and the complexing agent solution.

[0378] Process (D): A process in which the metal-containing aqueous solution, the pH adjustment solution, and the complexing agent solution, each filled in the raw material storage tank, are each transferred to the reaction channel by means of a transport pump, and the metal-containing aqueous solution, the pH adjustment solution, and the complexing agent solution are mixed and reacted in the reaction channel by rotating the stirring means to obtain a reaction product.

[0379] The above precursor for the positive electrode active material of a lithium secondary battery is measured by a laser diffraction particle size distribution measuring device, and in the obtained cumulative particle size distribution curve, when the total is set to 100%, the particle size D such that the cumulative volume from the small particle side is 60%. 60 (㎛) and particle size D at 10% 10 Ratio D of (㎛) 60 / D 10 The value of is 2.0 or less, and the BET specific surface area is 20 m² / g or more.

[0380]

[14] The above process (D) is a method for manufacturing a precursor for a lithium secondary battery positive electrode active material described in

[13] , wherein the stirring means is rotated under conditions where the Taylor number is 60 or more and 20000 or less.

[0381] Examples

[0382] Next, the present invention will be explained in more detail by way of examples.

[0383] <Composition Analysis of LiMO>

[0384] The composition analysis of LiMO manufactured by the method described below was carried out by the method described in [Composition Analysis of LiMO] above.

[0385] <Analysis of Precursor Composition>

[0386] The compositional analysis of the precursor manufactured by the method described below was carried out by the following method.

[0387] First, the metal complex hydroxide obtained as a precursor was maintained at 650 °C for 5 hours under an atmospheric temperature, and then cooled to room temperature to obtain a metal complex oxide. The weight (g) of the metal complex hydroxide and the metal complex oxide was measured, and the weight loss rate (%) of the precursor before and after heating was calculated using the following formula.

[0388] Weight loss rate of precursor (%) = (Weight of metal complex hydroxide (g) - Weight of metal complex oxide (g)) ÷ Weight of metal complex hydroxide (g) × 100

[0389] The composition analysis of the metal complex hydroxide and metal complex oxide was performed by dissolving the powders of the metal complex hydroxide and metal complex oxide in hydrochloric acid and then using an ICP emission spectroscopic analyzer (Optima 7300 manufactured by PerkinElmer Inc.).

[0390] In addition, from the total mass part (%) of the metal in the metal complex hydroxide obtained by compositional analysis, the total molar mass (g / mol) of the metal in the metal complex hydroxide, and the weight loss rate (%) of the precursor, z and t in the following compositional formula (A) were each calculated using the following formula.

[0391] Ni 1-x M x O z (OH) 2-t ··· (A)

[0392] z = (100 - Total mass part of metal in metal complex hydroxide (%) - (Molar mass of oxygen (g / mol) + Molar mass of hydrogen (g / mol)) × 2 ÷ (Molar mass of oxygen (g / mol) + Molar mass of hydrogen (g / mol) × 2) × Weight loss rate of precursor (%)) ÷ Molar mass of oxygen (g / mol) ÷ Total mass part of metal in metal complex hydroxide (%) × Total molar mass of metal in metal complex hydroxide (g / mol)

[0393] t = 2 - (Molar mass of oxygen (g / mol) + Molar mass of hydrogen (g / mol)) × 2 ÷ (Molar mass of oxygen (g / mol) + Molar mass of hydrogen (g / mol) × 2) × Weight loss rate of precursor (%) ÷ (Molar mass of oxygen (g / mol) + Molar mass of hydrogen (g / mol)) ÷ Total mass part of metal in metal complex hydroxide (%) × Total molar mass of metal in metal complex hydroxide (g / mol)

[0394] <Measurement of Particle Size Distribution>

[0395] The cumulative volumetric particle size distribution of the precursor and LiMO prepared by the method described below was measured by the method described in [Measurement of Cumulative Volumetric Particle Size Distribution] above. The obtained D 10 , D 50 , D 60 Using the value of, D 60 / D 10 , D 10 / D50 Each was calculated.

[0396] <BET Specific Surface Area>

[0397] The BET specific surface area of ​​the precursor or LiMO prepared by the method described below was measured by the method described in [Measurement of BET specific surface area] above.

[0398] <X-ray diffraction measurement using CuKα rays>

[0399] The powder X-ray diffraction measurement of LiMO prepared by the method described below was carried out by the method described in [Powder X-ray Diffraction Measurement] above, and α / β was calculated from the obtained α and β. In addition, as a result of the measurement, all LiMO prepared by the method described below had a hexagonal crystal structure belonging to the space group R-3m.

[0400] <Measurement of Cycle Maintenance Rate>

[0401] The cycle retention rate was measured by the method described in the [Method for Measuring Cycle Retention Rate] above. In addition, the initial efficiency was calculated using the values ​​of the initial discharge capacity and the initial charge capacity according to the following formula.

[0402] First-cycle efficiency = First-cycle discharge capacity (mAh / g) ÷ First-cycle charge capacity (mAh / g) × 100

[0403] ≪Example 1≫

[0404] For the reaction apparatus, a Taylor vortex continuous stirring reaction apparatus (manufactured by Chipton Co., Ltd., TVF-1 type) was used.

[0405] In the Taylor vortex continuous stirring reaction device (40) shown in FIG. 3, the inner cylinder diameter Ro of the cylinder (41) is 101 mm, the outer cylinder diameter Ri of the stirring means (42) is 91.8 mm, and the gap width (d1), which is the distance between the cylinder (41) and the stirring means (42), is 4.6 mm. The gap width (d1) is the value obtained by multiplying the difference between the inner cylinder diameter Ro of the cylinder (41) and the outer cylinder diameter Ri of the stirring means (42) by 1 / 2.

[0406] A metal-containing aqueous solution was prepared by mixing an aqueous nickel sulfate solution, an aqueous cobalt sulfate solution, and an aqueous manganese sulfate solution in a ratio such that the atomic ratio of Ni, Co, and Mn was 91:5:4.

[0407] The adjusted metal-containing aqueous solution was filled into the raw material liquid storage tank (T1) shown in Fig. 2, the sodium hydroxide aqueous solution as the pH adjustment solution was filled into the raw material liquid storage tank (T2), and the ammonium sulfate aqueous solution as the complexing agent solution was filled into the raw material liquid storage tank (T3).

[0408] The inlet port (43a) shown in FIG. 3 is connected to the raw material liquid storage tank (T1) via the transport pump (P1) and heat exchanger (H1) shown in FIG. 2, the inlet port (43b) is connected to the raw material liquid storage tank (T2) via the transport pump (P2) and heat exchanger (H2), and the inlet port (43c) is connected to the raw material liquid storage tank (T3) via the transport pump (P3) and heat exchanger (H3).

[0409] After filling the reaction channel with water, the fluid temperature inside the reaction channel (S) was maintained at 55°C.

[0410] While rotating the stirring means (42) of the Taylor vortex continuous stirring reaction device (40), a metal-containing aqueous solution from the inlet port (43a), an aqueous solution of sodium hydroxide from the inlet port (43b), and an aqueous solution of ammonium sulfate from the inlet port (43c) were each continuously introduced into the reaction channel (S) at a ratio such that the ratio of the number of moles of metal to the number of moles of ammonium sulfate is 3.59 and the ratio of the number of moles of sodium hydroxide to the number of moles of metal is 8.68.

[0411] At this time, a thermometer was installed at the temperature measurement location Mb, and the temperature of the sodium hydroxide solution was adjusted by a heat exchanger (H2) under the condition that the difference between the highest and lowest temperatures of the sodium hydroxide solution at the temperature measurement location Mb was 1.4 ℃.

[0412] The rotational speed of the stirring means (42) was set to 183 rad / s, the Taylor number to 5140, and the total introduction rate of the total raw material liquid to 5.14 mL / min. After the reaction product was retained in the reaction channel (S) for 112 minutes, the nickel-cobalt-manganese composite hydroxide particles were recovered from the outlet (44) and stored in the reaction product storage tank (50).

[0413] After washing the particles of nickel-cobalt-manganese complex hydroxide, dehydrate them using a centrifuge, isolate them, and dry them at 120°C to obtain nickel-cobalt-manganese complex hydroxide 1.

[0414] As a result of the compositional analysis of nickel-cobalt-manganese complex hydroxide 1, in compositional formula (A), x = 0.092, z = 0.12, t = -0.12, and the elements M were Co and Mn.

[0415] D of nickel-cobalt-manganese complex hydroxide 1 60 / D 10 , BET specific surface area, D 10 / D 50 , 6 / (D 50 Write the value of × S) in Table 1 below.

[0416] ≪Example 2≫

[0417] Nickel-cobalt-manganese composite hydroxide 2 was obtained by the same method as in Example 1, except that the ratio of the number of moles of metal to the number of moles of ammonium sulfate was 3.56, the rotational speed of the stirring means (42) was 79 rad / s, the Taylor number was 5140, the total introduction rate of the total raw material solution was 5.11 mL / min, the ratio of the number of moles of sodium hydroxide to the number of moles of metal was 8.67, the residence time in the reaction channel was 113 min, and the temperature of the sodium hydroxide aqueous solution was adjusted so that the difference between the highest and lowest temperatures of the sodium hydroxide aqueous solution at the temperature measurement position Mb was 1.3 ℃.

[0418] As a result of the compositional analysis of nickel-cobalt-manganese complex hydroxide 2, in compositional formula (A), x = 0.091, z = 0.09, t = -0.21, and the elements M were Co and Mn.

[0419] D of nickel-cobalt-manganese complex hydroxide 2 60 / D 10 , BET specific surface area, D 10 / D 50 , 6 / (D 50 Write the value of × S) in Table 1 below.

[0420] ≪Comparative Example 1≫

[0421] Nickel-cobalt-manganese complex hydroxide 3 was obtained by the same method as in Example 1, except that the temperature of the sodium hydroxide aqueous solution was adjusted under conditions where the ratio of the molar amount of metal to the molar amount of ammonium sulfate was 9.53, the total introduction rate of the raw material solution was 5.26 mL / min, the ratio of the molar amount of sodium hydroxide to the molar amount of metal was 7.05, the residence time in the reaction channel was 109 min, and the difference between the highest and lowest temperatures of the sodium hydroxide aqueous solution at the temperature measurement position Mb was 1.9 ℃.

[0422] As a result of the compositional analysis of nickel-cobalt-manganese complex hydroxide 3, in compositional formula (A), x = 0.091, z = 0.08, t = -0.11, and the elements M were Co and Mn.

[0423] D of nickel-cobalt-manganese complex hydroxide 3 60 / D 10 , BET specific surface area, D 10 / D 50 , 6 / (D 50 Write the value of × S) in Table 1 below.

[0424] ≪Comparative Example 2≫

[0425] A device having a reaction vessel equipped with a stirrer and an overflow pipe, a concentration tank connected to the overflow pipe, and a mechanism for circulating from the concentration tank to the reaction vessel was used, and after water was put into the reaction vessel equipped with a stirrer and an overflow pipe, an aqueous sodium hydroxide solution was added, and the temperature of the solution in the reaction vessel was maintained at 50°C.

[0426] A nickel sulfate aqueous solution, a cobalt sulfate aqueous solution, and a manganese sulfate aqueous solution were mixed in a ratio such that the atomic ratio of Ni, Co, and Mn was 91:5:4, and a metal-containing aqueous solution was prepared.

[0427] Next, the adjusted metal-containing aqueous solution and the ammonium sulfate aqueous solution were added to the reaction vessel under stirring using a batch co-precipitation method as complexing agents. An aqueous sodium hydroxide solution was added dropwise under conditions where the pH of the solution in the reaction vessel was 10.5 (measured at a temperature of 40 ℃). After 33 hours, the dropwise addition of the sodium hydroxide solution was stopped, and particles of nickel-cobalt-manganese complex hydroxide were obtained.

[0428] After washing the particles of the nickel-cobalt-manganese complex hydroxide, dehydrate them using a centrifuge, isolate them, and dry them at 105°C to obtain nickel-cobalt-manganese complex hydroxide 4.

[0429] As a result of the compositional analysis of nickel-cobalt-manganese complex hydroxide 4, in compositional formula (A), x = 0.091, z = 0.13, t = -0.18, and the elements M were Co and Mn.

[0430] D of nickel-cobalt-manganese complex hydroxide 4 60 / D 10 , BET specific surface area, D 10 / D 50 , 6 / (D 50 Write the value of × S) in Table 1 below.

[0431] ≪Comparative Example 3≫

[0432] After adding water to a reaction vessel equipped with a stirrer and an overflow pipe, an aqueous sodium hydroxide solution was added, and the solution temperature was maintained at 60°C.

[0433] A nickel sulfate aqueous solution, a cobalt sulfate aqueous solution, and a manganese sulfate aqueous solution were mixed in a ratio such that the atomic ratio of Ni, Co, and Mn was 91:5:4, and a metal-containing aqueous solution was prepared.

[0434] Next, the adjusted metal-containing aqueous solution and the ammonium sulfate aqueous solution were continuously added to the reaction apparatus under stirring as complexing agent solutions. An aqueous sodium hydroxide solution was added dropwise at specific times under conditions where the pH of the solution in the reaction apparatus was 12.0 (measured at a temperature of 40 ℃), and particles of nickel-cobalt-manganese complex hydroxide were obtained.

[0435] After washing the particles of nickel-cobalt-manganese complex hydroxide, dehydrate them using a centrifuge, isolate them, and dry them at 105°C to obtain nickel-cobalt-manganese complex hydroxide powder.

[0436] The above nickel-cobalt-manganese composite hydroxide powder was classified using an elbow jet classifier manufactured by Matsubo Co., Ltd. to obtain nickel-cobalt-manganese composite hydroxide 5.

[0437] As a result of the compositional analysis of nickel-cobalt-manganese complex hydroxide 5, in compositional formula (A), x = 0.090, z = 0.05, t = -0.18, and the elements M were Co and Mn.

[0438] D of nickel-cobalt-manganese complex hydroxide 5 60 / D 10 , BET specific surface area, D 10 / D 50 , 6 / (D 50 Write the value of × S) in Table 1 below.

[0439]

[0440] ≪Example 3≫

[0441] The obtained nickel-cobalt-manganese complex hydroxide 1 was maintained at 650°C for 5 hours under an oxygen-containing atmosphere, and then cooled to room temperature to obtain nickel-cobalt-manganese complex oxide 1.

[0442] A mixture was obtained by mixing lithium hydroxide, weighed at a ratio such that the amount of Li (molar ratio) to the total amount of Ni, Co, and Mn contained in the obtained nickel-cobalt-manganese complex oxide 1 is 1.10, and potassium carbonate, weighed at a ratio such that the amount of potassium carbonate (molar ratio) to the total amount of potassium carbonate, an inert flux, is 0.10, by mortar and pestle.

[0443] Next, the obtained mixture was maintained at 790°C for 5 hours in an oxygen-containing atmosphere, and then cooled to room temperature to obtain a sintered product.

[0444] After washing the obtained calcined product, dehydrate it, maintain it at 760°C for 5 hours under an oxygen-containing atmosphere, and then cool it to room temperature to obtain powdered LiMO-1.

[0445] As a result of analyzing the composition of LiMO-1, in composition formula (1), m = 0.02 and n = 0.096, and the elements M were Co and Mn.

[0446] LiMO-1's D60 / D 10 , BET specific surface area, D 10 / D 50 The values ​​of , α / β are recorded in Table 2 below.

[0447] ≪Example 4≫

[0448] A mixture was obtained by mixing the obtained nickel-cobalt-manganese complex oxide 1, lithium hydroxide weighed at a ratio such that the amount of Li (molar ratio) to the total amount of Ni, Co, and Mn contained in the obtained nickel-cobalt-manganese complex oxide 1 is 1.10, and potassium carbonate weighed at a ratio such that the amount of potassium carbonate (molar ratio) to the total amount of potassium carbonate, an inert flux, is 0.10 by mortar and pestle.

[0449] Next, the obtained mixture was maintained at 820°C for 5 hours under an oxygen-containing atmosphere, and then cooled to room temperature to obtain a sintered product.

[0450] After washing the obtained calcined product, dehydrate it, maintain it at 760°C for 5 hours under an oxygen-containing atmosphere, cool it to room temperature, and obtain powdered LiMO-2.

[0451] As a result of analyzing the composition of LiMO-2, in composition formula (1), m = 0.01 and n = 0.095, and the elements M were Co and Mn.

[0452] LiMO-2's D 60 / D 10 , BET specific surface area, D 10 / D 50 The values ​​of , α / β are recorded in Table 2 below.

[0453] ≪Example 5≫

[0454] A mixture was obtained by mixing the obtained nickel-cobalt-manganese complex oxide 1, lithium hydroxide weighed at a ratio such that the amount of Li (molar ratio) to the total amount of Ni, Co, and Mn contained in the obtained nickel-cobalt-manganese complex oxide 1 is 1.10, and potassium carbonate weighed at a ratio such that the amount of potassium carbonate (molar ratio) to the total amount of potassium carbonate, an inert flux, is 0.10 by mortar and pestle.

[0455] Next, the obtained mixture was maintained at 850°C for 5 hours in an oxygen-containing atmosphere to fire, and then cooled to room temperature to obtain a fired product.

[0456] After washing the obtained calcined product, dehydrate it, maintain it at 760°C for 5 hours under an oxygen-containing atmosphere, cool it to room temperature, and obtain powdered LiMO-3.

[0457] As a result of analyzing the composition of LiMO-3, in composition formula (1), m = 0.00 and n = 0.095, and the elements M were Co and Mn.

[0458] LiMO-3's D 60 / D 10 , BET specific surface area, D 10 / D 50 The values ​​of , α / β are recorded in Table 2 below.

[0459] ≪Comparative Example 4≫

[0460] A mixture was obtained by mixing the obtained nickel-cobalt-manganese complex hydroxide 3, lithium hydroxide weighed at a ratio such that the amount of Li (molar ratio) to the total amount of Ni, Co, and Mn contained in the obtained nickel-cobalt-manganese complex hydroxide is 1.10, and potassium carbonate weighed at a ratio such that the amount of potassium carbonate (molar ratio) to the total amount of potassium carbonate, an inert flux, is 0.10 by mortar and pestle.

[0461] Next, the obtained mixture was maintained at 820°C for 5 hours under an oxygen-containing atmosphere, and then cooled to room temperature to obtain a sintered product.

[0462] After washing the obtained calcined product, dehydrate it, maintain it at 760°C for 5 hours under an oxygen-containing atmosphere, cool it to room temperature, and obtain powdered LiMO-4.

[0463] As a result of analyzing the composition of LiMO-4, in composition formula (1), m = 0.01 and n = 0.092, and the elements M were Co and Mn.

[0464] LiMO-4's D 60 / D 10 , BET specific surface area, D 10 / D 50 The values ​​of , α / β are recorded in Table 2 below.

[0465] ≪Comparative Example 5≫

[0466] A mixture was obtained by mixing the obtained nickel-cobalt-manganese complex hydroxide 4, lithium hydroxide weighed at a ratio such that the amount of Li (molar ratio) to the total amount of Ni, Co, and Mn contained in the obtained nickel-cobalt-manganese complex hydroxide 4 is 1.20, and potassium sulfate weighed at a ratio such that the amount of potassium sulfate (molar ratio) to the total amount of potassium sulfate, an inert flux, is 0.10 by mortar and pestle.

[0467] Next, the obtained mixture was maintained at 940°C for 5 hours in an oxygen-containing atmosphere, and then cooled to room temperature to obtain a sintered product.

[0468] After washing the obtained calcined product, dehydrate it, maintain it at 760°C for 5 hours under an oxygen-containing atmosphere, cool it to room temperature, and obtain powdered LiMO-5.

[0469] As a result of analyzing the composition of LiMO-5, in composition formula (1), m = -0.07 and n = 0.097, and the elements M were Co and Mn.

[0470] LiMO-5's D 60 / D 10 , BET specific surface area, D10 / D 50 The values ​​of , α / β are recorded in Table 2 below.

[0471] ≪Comparative Example 6≫

[0472] A mixture was obtained by mixing the obtained nickel-cobalt-manganese complex hydroxide 5, lithium hydroxide weighed at a ratio such that the amount of Li (molar ratio) to the total amount of Ni, Co, and Mn contained in the obtained nickel-cobalt-manganese complex hydroxide 5 is 1.10, and potassium carbonate weighed at a ratio such that the amount of potassium carbonate (molar ratio) to the total amount of potassium carbonate, an inert flux, is 0.10 by mortar and pestle.

[0473] Next, the obtained mixture was maintained at 850°C for 5 hours under an oxygen atmosphere, and then cooled to room temperature to obtain a sintered product.

[0474] After washing the obtained calcined product, dehydrate it, maintain it at 760°C for 5 hours under an oxygen-containing atmosphere, cool it to room temperature, and obtain powdered LiMO-6.

[0475] As a result of analyzing the composition of LiMO-6, in composition formula (1), m = 0.01 and n = 0.089, and the elements M were Co and Mn.

[0476] LiMO-6's D 60 / D 10 , BET specific surface area, D 10 / D 50 The values ​​of , α / β are recorded in Table 2 below.

[0477] Table 2 lists the initial charge capacity, initial discharge capacity, initial efficiency, and cycle retention rate of lithium secondary batteries using LiMO of Examples 3 to 5 and Comparative Examples 4 to 6 as CAM.

[0478]

[0479] As described in the results above, it was confirmed that the lithium secondary battery using LiMO of Examples 3 to 5 as CAM had an improved cycle retention rate compared to the comparative example. Explanation of the symbols

[0480] 1 : Separator 2 : Straight Drama 3 : Negative pole 4: Electrode group 5 : Battery can 6 : Electrolyte 7: Top Insulator 8 : Bongguche 10: Lithium secondary battery 21: Straight Drama Lead 31: Negative lead 40: Taylor vortex continuous stirring reaction device 41 : Cylinder 42: Stirring means 43 : Introduction 44 : Outlet S: Reaction Euro U: 1 set of phantom vortex U1: First annular vortex U2: Second annular vortex Ma, Mb, and Mc: Temperature measurement locations Ro: Inner cylinder diameter of the cylinder (41) Ri: Diameter of the outer cylinder of the stirring means (42) d1 : Gap width T1, T2, and T3: Raw material liquid storage tanks P1, P2 and P3: Transport pumps H1, H2 and H3: Heat exchangers 50: Reactant storage tank 60: Reaction means

Claims

Claim 1 A precursor for a positive electrode active material of a lithium secondary battery containing at least Ni and element M, wherein the element M is one or more elements selected from the group consisting of Co, Mn, Fe, Cu, Ti, Mg, Al, W, Mo, Nb, Zn, Sn, Zr, Ga, V, B, Si, S, and P (provided that the element M includes at least Mn), and the particle size D such that when the total is set to 100% in the cumulative particle size distribution curve obtained by measuring the precursor for the positive electrode active material of a lithium secondary battery using a laser diffraction particle size distribution measuring device, the cumulative volume from the small particle side is 60%. 60 (㎛) and particle size D at 10% 10 Ratio D of (㎛) 60 / D 10 A precursor for a positive electrode active material of a lithium secondary battery, wherein the value of is 2.0 or less, the BET specific surface area is 30 m² / g or more, and the following formula (B) is satisfied. 0.027 ≤ 6 / (D 50 × S) ≤ 0.035 g / ㎤··· (B)(D 50 ε is the particle size (μm) at which the cumulative volume from the small particle side is 50% when the total is set to 100% in the above cumulative particle size distribution curve. S is the BET specific surface area (m² / g) of the precursor for the positive electrode active material of a lithium secondary battery. Claim 2 A precursor for a positive electrode active material of a lithium secondary battery, satisfying the following compositional formula (A) in claim 1. 1-x M x O z (OH) 2-t ··· (A)(In compositional formula (A), 0 < x ≤ 0.3, 0 ≤ z ≤ 3, and -0.5 ≤ t ≤ 2 are satisfied, and M is one or more elements selected from the group consisting of Co, Mn, Fe, Cu, Ti, Mg, Al, W, Mo, Nb, Zn, Sn, Zr, Ga, V, B, Si, S, and P. provided that the element M includes at least Mn.) Claim 3 In claim 1 or 2, the above D 10 (㎛) and, in the above cumulative particle size distribution curve, particle diameter D at which the cumulative volume from the fine particle side is 50% when the whole is set to 100%. 50 Ratio D of (㎛) 10 / D 50 A precursor for a positive electrode active material of a lithium secondary battery, having a value of 0.55 or higher. Claim 4 A precursor for a positive electrode active material of a lithium secondary battery, wherein, in claim 1 or 2, the BET specific surface area is 80 m² / g or less. Claim 5 A lithium metal composite oxide having a layered structure, containing at least Li and Ni and element M, wherein the element M is one or more elements selected from the group consisting of Co, Mn, Fe, Cu, Ti, Mg, Al, W, Mo, Nb, Zn, Sn, Zr, Ga, V, B, Si, S, and P, and wherein the lithium metal composite oxide is measured by a laser diffraction particle size distribution measuring device, and in the obtained cumulative particle size distribution curve, the cumulative volume from the small particle side is 60% when the total is set to 100%, and the particle size D 60 (㎛) and particle size D at 10% 10 Ratio D of (㎛) 60 / D 10 The value of is 2.19 or higher and 2.5 or lower, the BET specific surface area is 0.30 m² / g or higher and 0.50 m² / g or lower, and is represented by the following composition formula (1), and the above D 10 (㎛) and, in the above cumulative particle size distribution curve, particle diameter D at which the cumulative volume from the fine particle side is 50% when the whole is set to 100%. 50 Ratio D of (㎛) 10 / D 50 Lithium metal composite oxide, which is 0.40 or more and less than 0.60.Li[Li m (Ni (1-n) M n ) 1-m ]O2··· (1)(wherein M is one or more elements selected from the group consisting of Co, Mn, Fe, Cu, Ti, Mg, Al, W, Mo, Nb, Zn, Sn, Zr, Ga, V, B, Si, S and P, satisfying -0.1 ≤ m ≤ 0.2, 0 < n ≤ 0.3, and 0 < m + n < 0.3.) Claim 6 A lithium metal composite oxide according to claim 5, wherein the ratio α / β of the crystallite size α obtained from a peak within the range 2θ = 18.7 ± 2° and the crystallite size β obtained from a peak within the range 2θ = 44.6 ± 2° in X-ray diffraction measurements using CuKα rays is 1.71 or greater and 2.50 or less. Claim 7 A positive electrode active material for a lithium secondary battery comprising a lithium metal composite oxide as described in claim 5 or 6. Claim 8 A positive electrode for a lithium secondary battery comprising the positive electrode active material for a lithium secondary battery described in claim 7. Claim 9 A lithium secondary battery having a positive electrode for a lithium secondary battery as described in claim 8. Claim 10 delete Claim 11 delete Claim 12 delete

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