Lithium metal complex oxide, production method for activated lithium metal complex oxide, activated lithium metal complex oxide powder, positive pole active material for non-aqueous electrolyte secondary battery, and non-aqueous electrolyte secondary battery

Abstract

To provide a method for producing activated lithium metal complex oxide which, when used as a positive pole active material of a non-aqueous electrolyte secondary battery including a lithium ion secondary battery, exhibits a more excellent cycle property and lower resistance; and lithium metal complex oxide used in the production method.SOLUTION: Lithium metal complex oxide according to the present disclosure is represented by the general formula LixNi1-y-z-wCoyMnzM1wO2+α(where, M1 is one or more elements other than Li, Ni, Co, Mn, and O and 0<x≤1.2, 0≤y≤0.4, 0≤z≤0.4, 0≤w≤0.1, and -1.0≤α≤0.5 are satisfied) and has a cumulative pore volume in a pore size range of 25nm or more and 334nm or less as measured by a mercury intrusion technique of 25μL / g or more.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to a lithium metal composite oxide, a method for producing an activated lithium metal composite oxide, an activated lithium metal composite oxide powder, a positive electrode active material for a non-aqueous electrolyte secondary battery, and a non-aqueous electrolyte secondary battery. Regarding. [Background technology]

[0002] In recent years, portable and cordless electronic devices such as mobile phones and laptops have become increasingly popular, and non-aqueous secondary batteries, which are small, lightweight, and have high energy density, are used as power sources for these devices. Among these, lithium-ion secondary batteries, which use lithium nickel oxide as the positive electrode and have the advantage of having a large charge / discharge capacity, are widely used.

[0003] As a positive electrode active material for such lithium-ion secondary batteries, research has been actively conducted on layered rock salt oxide-based positive electrode active materials for lithium-ion secondary batteries (basic composition: Li(NiM)O2), which are versatile solid solutions of nickel (Ni) and other transition metals M.

[0004] Among these layered rock salt oxide-based positive electrode active materials, those containing, for example, tungsten (W) in addition to the transition metals that have traditionally been widely used, such as cobalt (Co), manganese (Mn), magnesium (Mg), and aluminum (Al), are attracting attention. The presence of tungsten on the particle surface or particle interface of the positive electrode active material improves electronic conductivity, and attempts are being made to use this positive electrode active material to produce higher performance lithium-ion secondary batteries.

[0005] For example, Patent Document 1 describes a method for producing a layered rock salt oxide-based positive electrode active material by adding a tungsten compound when mixing a composite oxide or composite hydroxide made of other transition metal compounds with a lithium compound, or when mixing another transition metal compound with a lithium compound, before a calcination step to obtain the positive electrode active material. [Prior art documents]

Patent Document

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] In recent years, in consideration of the global environment, the development and commercialization of electric vehicles and hybrid vehicles have been carried out, and for large-scale applications, there is an increasing demand for lithium-ion secondary batteries with better cycle characteristics and lower resistance.

[0008] This disclosure has been made in view of the above circumstances, and when used as a positive electrode active material of a non-aqueous electrolyte secondary battery including a lithium-ion secondary battery, it provides a method for producing an activated lithium metal composite oxide that exhibits better cycle characteristics and lower resistance, and a lithium metal composite oxide used in the production method.

Means for Solving the Problems

[0009] The inventors of the present invention have intensively studied to solve the above-mentioned problems. As a result, a general formula Li<00,000, w , z , 1-y-z-w , 2 , 1 , 2+α , 1 , <, x Ni 1-y-z-w Co y Mn z M 1 w O 2+α (where M 1 is one or more elements other than Li, Ni, Co, Mn, and O, 0 < x ≦ 1.2, 0 ≦ y ≦ 0.4, 0 ≦ z ≦ 0.4, 0 ≦ w ≦ 0.1, -1.0 ≦ α ≦ 0.5), and a lithium metal composite oxide having a cumulative pore volume of 25 μL / g or more in a pore diameter range of 25 nm or more and 334 nm or less measured by a mercury intrusion method, and M 1 independently of, one or more elements M other than Li, Ni, Co, Mn, and O 2A method for producing an activated lithium metal composite oxide includes a mixing step of obtaining a raw material mixture with a compound, and a firing step of firing the raw material mixture in an oxidizing atmosphere. The activated lithium metal composite oxide obtained by this method and a non-aqueous electrolyte secondary battery using the same exhibit more excellent cycle characteristics and lower resistance. Specifically, the present disclosure provides the following.

[0010] (1) A lithium metal composite oxide represented by the general formula Li x Ni 1-y-z-w Co y Mn z M 1 w O 2+α (where M 1 is one or more elements other than Li, Ni, Co, Mn, and O, 0 < x ≤ 1.2, 0 ≤ y ≤ 0.4, 0 ≤ z ≤ 0.4, 0 ≤ w ≤ 0.1, -1.0 ≤ α ≤ 0.5), and the cumulative pore volume in the pore diameter range of 25 nm or more and 334 nm measured by mercury intrusion porosimetry is 25 μL / g or more. Lithium metal composite oxide.

[0011] (2) A method for producing activated lithium metal composite oxide powder, including at least: a mixing step of mixing the lithium metal composite oxide according to (1) above and a compound containing one or more elements M 1 independently of M and other than Li, Ni, Co, Mn, and O to obtain a raw material mixture; and 2 a firing step of firing the raw material mixture in an oxidizing atmosphere. Method for producing activated lithium metal composite oxide powder.

[0012] (3) The method for producing activated lithium metal composite oxide powder according to (2) above, wherein in the mixing step, a lithium compound is further mixed.

[0013] (4) Activated lithium metal composite oxide powder, represented by the general formula Li[[ID=第44行]] x Ni 1-y-z-w-v Co<00000​​​​​​​​2+α (where M 1 and M 2 are each independently one or more elements other than Li, Ni, Co, Mn, and O, 0.9 ≦ x ≦ 1.2, 0 ≦ y ≦ 0.4, 0 ≦ z ≦ 0.4, 0 ≦ w ≦ 0.1, 0 < v ≦ 0.1, and -1.0 ≦ α ≦ 0.5), The ratio in terms of the amount of substance of the total amount of Ni, Co, and Mn in M 2 at the particle center to the total amount of Ni, Co, and Mn in M 2 at 1 μm from the surface is 0.90 or more with respect to the ratio in terms of the amount of substance of the total amount of Ni, Co, and Mn in M Activated lithium metal composite oxide powder.

[0014] (5) M 2 is W, the activated lithium metal composite oxide powder according to (4) above.

[0015] (6) The activated lithium metal composite oxide powder according to (4) or (5) above, including secondary particles with a distance from the surface to the particle center of 10 μm or more.

[0016] (7) A positive electrode active material for a non-aqueous electrolyte secondary battery, including the activated lithium metal composite oxide powder according to (4) or (5) above.

[0017] (8) A non-aqueous electrolyte secondary battery, including the positive electrode active material for a non-aqueous electrolyte secondary battery according to (7) above. [Effects of the Invention]

[0018] According to the present disclosure, when used as a positive electrode active material for a non-aqueous electrolyte secondary battery including a lithium ion secondary battery, a method for manufacturing an activated lithium metal composite oxide that exhibits more excellent cycle characteristics and lower resistance, and a lithium metal composite oxide as a precursor used in the manufacturing method can be provided. [Modes for Carrying Out the Invention]

[0019] Hereinafter, embodiments of the present disclosure (hereinafter referred to as "the present embodiments") will be described. However, the present disclosure is not limited to the description of the embodiments and can be implemented with appropriate modifications.

[0020] ≪Lithium metal composite oxide≫ The lithium metal composite oxide according to an embodiment of the present disclosure has the general formula Li x Ni 1-y-z-w Co y Mn z M 1 w O 2+α (where M 1 is one or more elements other than Li, Ni, Co, Mn, and O, 0 < x ≤ 1.2, 0 ≤ y ≤ 0.4, 0 ≤ z ≤ 0.4, 0 ≤ w ≤ 0.1, and -1.0 ≤ α ≤ 0.5), and is measured by mercury intrusion porosimetry, and the cumulative pore volume in the pore diameter range of 25 nm or more and 334 nm is 25 μL / g or more.

[0021] The activated lithium metal composite oxide obtained by firing such a lithium metal composite oxide by the method described later exhibits more excellent cycle characteristics and lower resistance when used as a positive electrode active material of a non-aqueous electrolyte secondary battery including a lithium ion secondary battery.

[0022] As the chemical composition of the lithium metal composite oxide, the general formula Li x Ni 1-y-z-w Co y Mn z M 1 w O 2+α (where M 1 is one or more elements other than Li, Ni, Co, Mn, and O, 0 < x ≤ 1.2, 0 ≤ y ≤ 0.4, 0 ≤ z ≤ 0.4, 0 ≤ w ≤ 0.1, and -1.0 ≤ α ≤ 0.5) is not particularly limited as long as it is represented by the formula.

[0023] In the general formula, the value of x is not particularly limited as long as it is within the range of 0 < x ≤ 1.2. For example, it may be 0.01 or more, 0.02 or more, 0.03 or more, 0.04 or more, 0.05 or more, 0.06 or more, 0.07 or more, 0.08 or more, 0.09 or more, 0.1 or more, 0.11 or more, 0.12 or more, 0.13 or more, 0.14 or more, 0.15 or more, 0.16 or more, 0.17 or more, 0.18 or more, 0.19 or more, 0.2 or more, 0.21 or more, 0.22 or more, 0.23 or more, 0.24 or more, 0.25 or more, 0.26 or more, 0.27 or more, 0.28 or more, 0.29 or more, 0.3 or more, 0.31 or more, 0.32 or more, 0.33 or more, 0.34 or more, 0.35 or more, 0.36 or more, 0.37 or more, 0.38 or more, 0.39 or more, 0.4 or more, 0.41 or more, 0.42 or more, 0.43 or more, 0.44 or more, 0.45 or more, 0.46 or more, 0.47 or more, 0.48 or more, 0.49 or more, 0.5 or more, 0.51 or more, 0.52 or more, 0.53 or more, 0.54 or more, 0.55 or more, 0.56 or more, 0.57 or more, 0.58 or more, 0.59 or more, 0.6 or more, 0.61 or more, 0.62 or more, 0.63 or more,

[0024] 0.64 or more, 0.65 or more, 0.66 or more, 0.67 or more, 0.68 or more, 0.69 or more, 0.7 or more, 0.71 or more, 0.72 or more, 0.73 or more, 0.74 or more, 0.75 or more, 0.76 or more, 0.77 or more, 0.78 or more, 0.79 or more, 0.8 or more, 0.81 or more, 0.82 or more, 0.83 or more, 0.84 or more, 0.85 or more, 0.86 or more, 0.87 or more, 0.88 or more, 0.89 or more, 0.9 or more, 0.91 or more, 0.92 or more, 0.93 or more, 0.94 or more, 0.95 or more, 0.96 or more. On the other hand, the value of x may be 1.2 or less, 1.195 or less, 1.19 or less, 1.185 or less, 1.18 or less, 1.175 or less, 1.17 or less, 1.165 or less, 1.16 or less, 1.155 or less, 1.15 or less, 1.145 or less, 1.14 or less, 1.135 or less, 1.13 or less, 1.125 or less, 1.12 or less, 1.115 or less, 1.11 or less, 1.105 or less, 1.10 or less, 1.095 or less, 1.09 or less, 1.085 or less, 1.08 or less, 1.075 or less, 1.07 or less, 1.065 or less, 1.06 or less, 1.055 or less, 1.05 or less. <> <>

[0024] <> In the general formula, the value of y is not particularly limited as long as it is within the range of 0≦y≦0.4, and examples thereof include greater than 0, 0.001 or more, 0.0015 or more, 0.002 or more, 0.0025 or more, 0.003 or more, 0.0035 or more, 0.004 or more, 0.0045 or more, 0.005 or more, 0.0055 or more, 0.006 or more, 0.0065 or more, 0.007 or more, 0.0075 or more, 0.008 or more, 0.0085 or more, 0.009 or more, 0.0095 or more, 0.01 or more, 0.015 or more, 0.02 or more, 0.025 or more, 0.03 or more, 0.035 or more, 0.04 or more, 0.045 or more, 0.05 or more, 0.055 or more, 0.06 or more, 0.065 or more, 0.07 or more, 0.075 or more, 0.08 or more, 0.085 or more, 0.09 or more, 0.095 or more, 0.1 or more, 0.102 or more, 0.105 or more, 0.107 or more, 0.11 or more, 0.112 or more, 0.115 or more, 0.117 or more, 0.12 or more, 0.122 or more, 0.125 or more, 0.127 or more, 0.13 or more, 0.132 or more, 0.135 or more, 0.137 or more, 0.14 or more, 0.142 or more, 0.145 or more, 0.147 or more, 0.15 or more, 0.152 or more, 0.155 or more, 0.157 or more, 0.16 or more, 0.162 or more, 0.165 or more, 0.167 or more, 0.17 or more, 0.172 or more, 0.175 or more, 0.177 or more, 0.18 or more, 0.182 or more, 0.185 or more, 0.187 or more, 0.19 or more, 0.192 or more, 0.195 or more, 0.197 or more, 0.2 or more, 0.202 or more, 0.205 or more, 0.207 or more, 0.21 or more, 0.212 or more, 0.215 or more, 0.217 or more, 0.22 or more, 0.222 or more, 0.225 or more, 0.227 or more, 0.23 or more, 0.232 or more , 0.235 or more, 0.237 or more, 0.24 or more, 0.242 or more, 0.245 or more, 0.247 or more, 0.25 or more, 0.252 or more, 0.255 or more, 0.257 or more, 0.26 or more, 0.262 or more, 0.265 or more, 0.267 or more, 0.27 or more, 0.272 or more, 0.275 or more, 0.277 or more, 0.282 or more, 0.285 or more, 0.287 or more, 0.29 or more, 0.292 or more, 0.295 or more, 0.297 or more, 0.3 or more, 0.302 or more, 0.305 or more, 0.307 or more, 0.31 or more, 0.312 or more, 0.315 or more, 0.317 or more, 0.32 or more, 0.322 or more, 0.325 or more, 0.327 or more, 0.33 or more, 0.332 or more, 0.335 or more, 0.337 or more, 0.34 or more, 0.342 or more, 0.345 or more, 0.347 or more, 0.35 or more, 0.352 or more, 0.355 or more, 0.357 or more, 0.362 or more, 0.365 or more, 0.367 or more, 0.37 or more, 0.372 or more, 0.375 or more, 0.377 or more, 0.382 or more, 0.385 or more, 0.387 or more, 0.39 or more, 0.392 or more, 0.395 or more, 0.397 or more is preferred. On the other hand, the values ​​of y are 0.397 or less, 0.395 or less, 0.392 or less, 0.39 or less, 0.387 or less, 0.385 or less, 0.382 or less, 0.38 or less, 0.377 or less, 0.375 or less, 0 .372 or less, 0.367 or less, 0.365 or less, 0.362 or less, 0.36 or less, 0.357 or less, 0.355 or less, 0.352 or less, 0.35 or less, 0.347 or less, 0.345 or less, 0.342 or less Below, 0.34 or less, 0.337 or less, 0.335 or less, 0.332 or less, 0.33 or less, 0.327 or less, 0.325 or less, 0.322 or less, 0.32 or less, 0.317 or less, 0.315 or less, 0.3 12 or less, 0.31 or less, 0.307 or less, 0.305 or less, 0.302 or less, 0.3 or less, 0.297 or less, 0.295 or less, 0.292 or less, 0.29 or less, 0.287 or less, 0.285 or less, 0. 282 or less, 0.28 or less, 0.277 or less, 0.275 or less, 0.272 or less, 0.27 or less, 0.267 or less, 0.265 or less, 0.26 or less, 0.257 or less, 0.255 or less, 0.252 or less , 0.25 or less, 0.247 or less, 0.245 or less, 0.242 or less, 0.24 or less, 0.237 or less, 0.235 or less, 0.232 or less, 0.23 or less, 0.227 or less, 0.225 or less, 0.222 0.22 or less, 0.217 or less, 0.215 or less, 0.212 or less, 0.21 or less, 0.207 or less, 0.205 or less, 0.202 or less, 0.2 or less, 0.197 or less, 0.195 or less, 0.19 2 or less, 0.19 or less, 0.187 or less, 0.185 or less, 0.182 or less, 0.18 or less, 0.177 or less, 0.175 or less, 0.172 or less, 0.17 or less, 0.167 or less, 0.165 or less, 0.162 or less, 0.16 or less, 0.155 or less, 0.152 or less, 0.15 or less, 0.147 or less, 0.145 or less, 0.142 or less, 0.14 or less, 0.137 or less, 0.135 or less, 0.132 or less, 0.13 or less, 0.127 or less, 0.125 or less, 0.122 or less, 0.12 or less, 0.117 or less, 0.115 or less, 0.112 or less, 0.11 or less, 0.107 or less, 0.105 or less, 0.102 or less, 0.1 or less, 0.095 or less, 0.09 or less, 0.085 or less, 0.08 or less, 0.075 or less, 0.07 or less, 0.065 or less, 0 Preferably, it is 0.06 or less, 0.055 or less, 0.05 or less, 0.045 or less, 0.04 or less, 0.035 or less, 0.03 or less, 0.025 or less, 0.02 or less, 0.015 or less, 0.01 or less, 0.0095 or less, 0.009 or less, 0.0085 or less, 0.008 or less, 0.0075 or less, 0.007 or less, 0.0065 or less, 0.0055 or less, 0.005 or less, 0.0045 or less, 0.004 or less, 0.0035 or less, 0.003 or less, 0.0025 or less, 0.002 or less, 0.0015 or less, or 0.001 or less.

[0025] In the general formula, the value of z is not particularly limited as long as it is within the range of 0≦z≦0.4, and examples thereof include greater than 0, 0.001 or more, 0.0015 or more, 0.002 or more, 0.0025 or more, 0.003 or more, 0.0035 or more, 0.004 or more, 0.0045 or more, 0.005 or more, 0.0055 or more, 0.006 or more, 0.0065 or more, 0.007 or more, 0.0075 or more, 0.008 or more, 0.0085 or more, 0.009 or more, 0.0095 or more, 0.01 or more, 0.015 or more, 0.02 or more, 0.025 or more, 0.03 or more, 0.035 or more, 0.04 or more, 0.045 or more, 0.05 or more, 0.055 or more, 0.06 or more, 0.065 or more, 0.07 or more, 0.075 or more, 0.08 or more, 0.085 or more, 0.09 or more, 0.095 or more, 0.1 or more, 0.102 or more, 0.105 or more, 0.107 or more, 0.11 or more, 0.112 or more, 0.115 or more, 0.117 or more, 0.12 or more, 0.122 or more, 0.125 or more, 0.127 or more, 0.13 or more, 0.132 or more, 0.135 or more, 0.137 or more, 0.14 or more, 0.142 or more, 0.145 or more, 0.147 or more, 0.15 or more, 0.152 or more, 0.155 or more, 0.157 or more, 0.16 or more, 0.162 or more, 0.165 or more, 0.167 or more, 0.17 or more, 0.172 or more, 0.175 or more, 0.177 or more, 0.18 or more, 0.182 or more, 0.185 or more, 0.187 or more, 0.19 or more, 0.192 or more, 0.195 or more, 0.197 or more, 0.2 or more, 0.202 or more, 0.205 or more, 0.207 or more, 0.21 or more, 0.212 or more, 0.215 or more, 0.217 or more, 0.22 or more, 0.222 or more, 0.225 or more, 0.227 or more, 0.23 or more, 0.232 or more , 0.235 or more, 0.237 or more, 0.24 or more, 0.242 or more, 0.245 or more, 0.247 or more, 0.25 or more, 0.252 or more, 0.255 or more, 0.257 or more, 0.26 or more, 0.262 or more, 0.265 or more, 0.267 or more, 0.27 or more, 0.272 or more, 0.275 or more, 0.277 or more, 0.282 or more, 0.285 or more, 0.287 or more, 0.29 or more, 0.292 or more, 0.295 or more, 0.297 or more, 0.3 or more, 0.302 or more, 0.305 or more, 0.307 or more, 0.31 or more, 0.312 or more, 0.315 or more, 0.317 or more, 0.32 or more, 0.322 or more, 0.325 or more, 0.327 or more, 0.33 or more, 0.332 or more, 0.335 or more, 0.337 or more, 0.34 or more, 0.342 or more, 0.345 or more, 0.347 or more, 0.35 or more, 0.352 or more, 0.355 or more, 0.357 or more, 0.362 or more, 0.365 or more, 0.367 or more, 0.37 or more, 0.372 or more, 0.375 or more, 0.377 or more, 0.382 or more, 0.385 or more, 0.387 or more, 0.39 or more, 0.392 or more, 0.395 or more, 0.397 or more is preferred. On the other hand, the values ​​of z are 0.397 or less, 0.395 or less, 0.392 or less, 0.39 or less, 0.387 or less, 0.385 or less, 0.382 or less, 0.38 or less, 0.377 or less, 0.375 or less, 0 .372 or less, 0.367 or less, 0.365 or less, 0.362 or less, 0.36 or less, 0.357 or less, 0.355 or less, 0.352 or less, 0.35 or less, 0.347 or less, 0.345 or less, 0.342 or less Below, 0.34 or less, 0.337 or less, 0.335 or less, 0.332 or less, 0.33 or less, 0.327 or less, 0.325 or less, 0.322 or less, 0.32 or less, 0.317 or less, 0.315 or less, 0.3 12 or less, 0.31 or less, 0.307 or less, 0.305 or less, 0.302 or less, 0.3 or less, 0.297 or less, 0.295 or less, 0.292 or less, 0.29 or less, 0.287 or less, 0.285 or less, 0. 282 or less, 0.28 or less, 0.277 or less, 0.275 or less, 0.272 or less, 0.27 or less, 0.267 or less, 0.265 or less, 0.26 or less, 0.257 or less, 0.255 or less, 0.252 or less , 0.25 or less, 0.247 or less, 0.245 or less, 0.242 or less, 0.24 or less, 0.237 or less, 0.235 or less, 0.232 or less, 0.23 or less, 0.227 or less, 0.225 or less, 0.222 0.22 or less, 0.217 or less, 0.215 or less, 0.212 or less, 0.21 or less, 0.207 or less, 0.205 or less, 0.202 or less, 0.2 or less, 0.197 or less, 0.195 or less, 0.19 2 or less, 0.19 or less, 0.187 or less, 0.185 or less, 0.182 or less, 0.18 or less, 0.177 or less, 0.175 or less, 0.172 or less, 0.17 or less, 0.167 or less, 0.165 or less, 0.162 or less, 0.16 or less, 0.155 or less, 0.152 or less, 0.15 or less, 0.147 or less, 0.145 or less, 0.142 or less, 0.14 or less, 0.137 or less, 0.135 or less, 0.132 or less, 0.13 or less, 0.127 or less, 0.125 or less, 0.122 or less, 0.12 or less, 0.117 or less, 0.115 or less, 0.112 or less, 0.11 or less, 0.107 or less, 0.105 or less, 0.102 or less, 0.1 or less, 0.095 or less, 0.09 or less, 0.085 or less, 0.08 or less, 0.075 or less, 0.07 or less, 0.065 or less, 0 Preferably, it is 0.06 or less, 0.055 or less, 0.05 or less, 0.045 or less, 0.04 or less, 0.035 or less, 0.03 or less, 0.025 or less, 0.02 or less, 0.015 or less, 0.01 or less, 0.0095 or less, 0.009 or less, 0.0085 or less, 0.008 or less, 0.0075 or less, 0.007 or less, 0.0065 or less, 0.0055 or less, 0.005 or less, 0.0045 or less, 0.004 or less, 0.0035 or less, 0.003 or less, 0.0025 or less, 0.002 or less, 0.0015 or less, or 0.001 or less.

[0026] In the general formula, the value of w is not particularly limited as long as it is within the range of 0≦w≦0.1, and may be, for example, 0.001 or more, 0.0012 or more, 0.0015 or more, 0.0017 or more, 0.002 or more, 0.0022 or more, 0.0025 or more, 0.0027 or more, 0.003 or more, 0.0032 or more, 0.0035 or more, 0.0037 or more, 0.004 or more, 0.0042 or more. Above, 0.0045 or more, 0.0047 or more, 0.005 or more, 0.0052 or more, 0.0055 or more, 0.0057 or more, 0.006 or more, 0.0062 or more, 0.0065 or more, 0.0067 or more, 0.007 or more, 0.0072 or more, 0.0075 or more, 0.0077 or more, 0.008 or more, 0.0082 or more, 0.0085 or more, 0.0087 or more, 0 0.009 or more, 0.0092 or more, 0.0095 or more, 0.0097 or more, 0.01 or more, 0.012 or more, 0.015 or more, 0.017 or more, 0.02 or more, 0.022 or more, 0.025 or more, 0.027 or more, 0.03 or more, 0.032 or more, 0.035 or more, 0.037 or more, 0.04 or more, 0.042 or more, 0.045 or more, 0.047 or more, 0.0 It is preferable that the molecular weight is 5 or more, 0.052 or more, 0.055 or more, 0.057 or more, 0.06 or more, 0.062 or more, 0.065 or more, 0.067 or more, 0.07 or more, 0.072 or more, 0.075 or more, 0.077 or more, 0.082 or more, 0.085 or more, 0.087 or more, 0.09 or more, 0.092 or more, 0.095 or more, or 0.097 or more.On the other hand, the values ​​of w are 0.097 or less, 0.095 or less, 0.092 or less, 0.09 or less, 0.087 or less, 0.085 or less, 0.082 or less, 0.08 or less, 0.077 or less, 0.075 or less, 0.072 or less, 0.07 or less, 0.067 or less, 0.065 or less, 0.062 or less, 0.06 or less, 0.057 or less, 0.055 or less, 0. 052 or less, 0.05 or less, 0.047 or less, 0.045 or less, 0.042 or less, 0.04 or less, 0.037 or less, 0.035 or less, 0.032 or less, 0.03 or less, 0. 027 or less, 0.025 or less, 0.022 or less, 0.02 or less, 0.017 or less, 0.015 or less, 0.012 or less, 0.01 or less, 0.0097 or less, 0.0095 or less , 0.0092 or less, 0.009 or less, 0.0087 or less, 0.0085 or less, 0.0082 or less, 0.008 or less, 0.0077 or less, 0.0075 or less, 0.0072 less than or equal to 0.007, less than or equal to 0.0067, less than or equal to 0.0065, less than or equal to 0.0062, less than or equal to 0.006, less than or equal to 0.0057, less than or equal to 0.0055, less than or equal to 0.0052, 0.00 It is preferable that the molecular weight is 5 or less, 0.0047 or less, 0.0045 or less, 0.0042 or less, 0.004 or less, 0.0037 or less, 0.0035 or less, 0.0032 or less, 0.003 or less, 0.0027 or less, 0.0025 or less, 0.0022 or less, 0.002 or less, 0.0017 or less, 0.0015 or less, 0.0012 or less, or 0.001 or less.

[0027] In the general formula, the value of v is not particularly limited as long as it is within the range of 0≦v≦0.1, and may be, for example, 0.001 or more, 0.0012 or more, 0.0015 or more, 0.0017 or more, 0.002 or more, 0.0022 or more, 0.0025 or more, 0.0027 or more, 0.003 or more, 0.0032 or more, 0.0035 or more, 0.0037 or more, 0.004 or more, 0.0042 or more. Above, 0.0045 or more, 0.0047 or more, 0.005 or more, 0.0052 or more, 0.0055 or more, 0.0057 or more, 0.006 or more, 0.0062 or more, 0.0065 or more, 0.0067 or more, 0.007 or more, 0.0072 or more, 0.0075 or more, 0.0077 or more, 0.008 or more, 0.0082 or more, 0.0085 or more, 0.0087 or more, 0 0.009 or more, 0.0092 or more, 0.0095 or more, 0.0097 or more, 0.01 or more, 0.012 or more, 0.015 or more, 0.017 or more, 0.02 or more, 0.022 or more, 0.025 or more, 0.027 or more, 0.03 or more, 0.032 or more, 0.035 or more, 0.037 or more, 0.04 or more, 0.042 or more, 0.045 or more, 0.047 or more, 0.0 It is preferable that the molecular weight is 5 or more, 0.052 or more, 0.055 or more, 0.057 or more, 0.06 or more, 0.062 or more, 0.065 or more, 0.067 or more, 0.07 or more, 0.072 or more, 0.075 or more, 0.077 or more, 0.082 or more, 0.085 or more, 0.087 or more, 0.09 or more, 0.092 or more, 0.095 or more, or 0.097 or more.On the other hand, the values ​​of v are 0.097 or less, 0.095 or less, 0.092 or less, 0.09 or less, 0.087 or less, 0.085 or less, 0.082 or less, 0.08 or less, 0.077 or less, 0.075 or less, 0.072 or less, 0.07 or less, 0.067 or less, 0.065 or less, 0.062 or less, 0.06 or less, 0.057 or less, 0.055 or less, 0. 052 or less, 0.05 or less, 0.047 or less, 0.045 or less, 0.042 or less, 0.04 or less, 0.037 or less, 0.035 or less, 0.032 or less, 0.03 or less, 0. 027 or less, 0.025 or less, 0.022 or less, 0.02 or less, 0.017 or less, 0.015 or less, 0.012 or less, 0.01 or less, 0.0097 or less, 0.0095 or less , 0.0092 or less, 0.009 or less, 0.0087 or less, 0.0085 or less, 0.0082 or less, 0.008 or less, 0.0077 or less, 0.0075 or less, 0.0072 less than or equal to 0.007, less than or equal to 0.0067, less than or equal to 0.0065, less than or equal to 0.0062, less than or equal to 0.006, less than or equal to 0.0057, less than or equal to 0.0055, less than or equal to 0.0052, 0.00 It is preferable that the molecular weight is 5 or less, 0.0047 or less, 0.0045 or less, 0.0042 or less, 0.004 or less, 0.0037 or less, 0.0035 or less, 0.0032 or less, 0.003 or less, 0.0027 or less, 0.0025 or less, 0.0022 or less, 0.002 or less, 0.0017 or less, 0.0015 or less, 0.0012 or less, or 0.001 or less.

[0028] In the formula, element M 1 The element is not particularly limited as long as it is one or more elements other than Li, Ni, Co, Mn, and O, but examples that can be used include Al, Mg, Zn, Nb, W, Mo, Sb, V, Cr, Ca, Fe, Ga, Sr, Y, Ru, In, Sn, Ta, Bi, Zr, and B.

[0029] In the general formula, the value of α is not particularly limited as long as it is within the range of -1.0≦α≦0.5, and may be, for example, greater than -1, -0.95 or more, -0.9 or more, -0.85 or more, -0.8 or more, -0.75 or more, -0.7 or more, -0.65 or more, -0.6 or more, -0.5 or more, -0.45 or more, -0.4 or more, -0.35 or more, -0.30 or more, -0.25 or more, -0.2 or more, -0.15 or more, -0.1 or more, -0.075 or more, -0.05 or more, -0.025 or more, -0.02 or more, -0.015 or more, -0.01 or more, -0.05 or more, 0 or more, 0.001 or more, 0. 0.0015 or more, 0.002 or more, 0.0025 or more, 0.003 or more, 0.0035 or more, 0.004 or more, 0.0045 or more, 0.005 or more, 0.0055 or more, 0.006 or more, 0.0065 or more, 0.007 or more, 0.0075 or more, 0.008 or more, 0.0085 or more, 0.009 or more, 0.0095 or more, 0.01 or more, 0.015 or more, 0.02 or more, 0.025 or more, 0.03 or more, 0.035 or more, 0.04 or more, 0.045 or more, 0.05 or more, 0.055 or more, 0.06 or more, 0.065 or more, 0.07 or more, 0.075 or more, 0. 08 or higher, 0.085 or higher, 0.09 or higher, 0.095 or higher, 0.1 or higher, 0.102 or higher, 0.105 or higher, 0.107 or higher, 0.11 or higher, 0.112 or higher, 0.115 or higher, 0.117 or higher, 0.12 or higher, 0.122 or higher, 0.125 or higher, 0.127 or higher, 0.13 or higher, 0.132 or higher, 0.135 or higher, 0.137 or higher, 0.142 or higher, 0.145 or higher, 0.147 or higher, 0.15 or higher, 0.152 or higher, 0.155 or higher, 0.157 or higher, 0.16 or higher, 0.162 or higher, 0.165 or higher, 0.167 or higher, 0.17 or higher , 0.172 or more, 0.175 or more, 0.177 or more, 0.18 or more, 0.182 or more, 0.185 or more, 0.187 or more, 0.19 or more, 0.192 or more, 0.195 or more, 0.197 or more, 0.2 or more, 0.202 or more, 0.205 or more, 0.207 or more, 0.21 or more, 0.212 or more, 0.215 or more, 0.217 or more, 0.22 or more, 0.222 or more, 0.225 or more, 0.227 or more, 0.23 or more, 0.232 or more, 0.235 or more, 0.237 or more, 0.24 or more, 0.242 or more, 0.245 or more, 0.247 or more, 0.25 or more, 0.252 or more, 0.255 or more, 0.257 or more, 0.26 or more, 0.262 or more, 0.265 or more, 0.267 or more, 0.27 or more, 0.272 or more, 0.275 or more, 0.277 or more, 0.282 or more, 0.285 or more, 0.287 or more, 0.29 or more, 0.292 or more, 0.295 or more, 0.297 or more, 0.3 or more, 0.302 or more, 0.305 or more, 0.307 or more, 0.31 or more, 0.312 or more, 0. 315 or more, 0.317 or more, 0.32 or more, 0.322 or more, 0.325 or more, 0.327 or more, 0.33 or more, 0.332 or more, 0.335 or more, 0.337 or more, 0.34 or more, 0.342 or more, 0.345 or more, 0.347 or more, 0.35 or more, 0.352 or more, 0.355 or more, 0.357 or more, 0.362 or more, 0.365 or more, 0.367 or more, 0.37 or more, 0.372 or more, 0.375 or more, 0. 377 or more, 0.38 or more, 0.382 or more, 0.385 or more, 0.387 or more, 0.39 or more, 0.392 or more, 0.395 or more, 0.397 or more, 0.4 or more, 0.402 or more, 0.405 or more, 0.407 or more, 0.41 or more, 0.412 or more, 0.415 or more, 0.417 or more, 0.42 or more, 0.422 or more, 0.425 or more, 0.427 or more, 0.43 or more, 0.432 or more, 0.435 or more, 0.437 or more, 0. It is preferable that the molecular weight is 0.44 or more, 0.442 or more, 0.445 or more, 0.447 or more, 0.45 or more, 0.452 or more, 0.455 or more, 0.457 or more, 0.46 or more, 0.462 or more, 0.465 or more, 0.467 or more, 0.47 or more, 0.472 or more, 0.475 or more, 0.477 or more, 0.482 or more, 0.485 or more, 0.487 or more, 0.49 or more, 0.492 or more, 0.495 or more, or 0.497 or more. On the other hand, the values ​​of α are 0.497 or less, 0.495 or less, 0.492 or less, 0.49 or less, 0.487 or less, 0.485 or less, 0.482 or less, 0.48 or less, 0.477 or less, 0.475 or less, 0.472 or less, 0.467 or less, 0.465 or less. Below, 0.462 or less, 0.46 or less, 0.457 or less, 0.455 or less, 0.452 or less, 0.45 or less, 0.447 or less, 0.445 or less, 0.442 or less, 0.44 or less, 0.437 or less, 0.435 or less, 0.432 or less, 0.43 or less, 0.Below 427, below 0.425, below 0.422, below 0.42, below 0.417, below 0.415, below 0.412, below 0.41, below 0.407, below 0.405, below 0.402, below 0.4, below 0.397, below 0.395, below 0.392, below 0.39, below 0.387, below 0.385, below 0.382, below 0.38, below 0.377, below 0.375, below 0.372, below 0.367, below 0.365, below 0.362, below 0.36, below 0.357, below 0.355, below 0.352, below 0.35, below 0.347, 0.3 Below 45, below 0.342, below 0.34, below 0.337, below 0.335, below 0.332, below 0.33, below 0.327, below 0.325, below 0.322, below 0.32, below 0.317, below 0.315, below 0.312, below 0.31, below 0.307, below 0.305, below 0.302, below 0.3, below 0.297, below 0.295, below 0.292, below 0.29, below 0.287, below 0.285, below 0.282, below 0.28, below 0.277, below 0.275, below 0.272, below 0.27, below 0.267, 0.265 Below, below 0.26, below 0.257, below 0.255, below 0.252, below 0.25, below 0.247, below 0.245, below 0.242, below 0.24, below 0.237, below 0.235, below 0.232, below 0.23, below 0.227, below 0.225, below 0.222, below 0.22, below 0.217, below 0.215, below 0.212, below 0.21, below 0.207, below 0.205, below 0.202, below 0.2, below 0.197, below 0.195, below 0.192, below 0.19, below 0.187, below 0.185, below 0.182 Below 0.18, below 0.177, below 0.175, below 0.172, below 0.17, below 0.167, below 0.165, below 0.162, below 0.16, below 0.155, below 0.152, below 0.15, below 0.147, below 0.145, below 0.142, below 0.14, below 0.137, below 0.135, below 0.132, below 0.13, below 0.127, below 0.125, below 0.122, below 0.12, below 0.117, below 0.115, below 0.112, below 0.11, below 0.107, below 0.105, below 0.102, below 0.1, 0.It is preferably 0.095 or less, 0.09 or less, 0.085 or less, 0.08 or less, 0.075 or less, 0.07 or less, 0.065 or less, 0.06 or less, 0.055 or less, 0.05 or less, 0.045 or less, 0.04 or less, 0.035 or less, 0.03 or less, 0.025 or less, 0.02 or less, 0.015 or less, 0.01 or less, 0.0095 or less, 0.009 or less, 0.0085 or less, 0.008 or less, 0.0075 or less, 0.007 or less, 0.0065 or less, 0.006 or less, 0.0055 or less, 0.005 or less, 0.0045 or less, 0.004 or less, 0.0035 or less, 0.003 or less, 0.0025 or less, 0.002 or less, 0.0015 or less, 0.001 or less.

[0030] The cumulative pore volume in the pore diameter range of 25 nm or more and 334 nm is not particularly limited as long as it is 25 μL / g or more. For example, it may be 25.5 μL / g or more, 26 or more, 30 μL / g or more, 35 μL / g or more, 40 μL / g or more, 45 μL / g or more, 50 μL / g or more, 55 μL / g or more. On the other hand, the cumulative pore volume in the pore diameter range of 25 nm or more and 334 nm may be 150 μL / g or less, 120 μL / g or less, 100 μL / g or less, 90 μL / g or less, 80 μL / g or less, 70 μL / g or less. The method for measuring the cumulative pore volume in the pore diameter range of 25 nm or more and 334 nm follows the method shown in the examples described later.

[0031] ≪Activated Lithium Metal Composite Oxide Powder≫ The activated lithium metal composite oxide powder according to this embodiment has the general formula Li x Ni 1-y-z-w-v Co y Mn z M 1 w M 2 v O 2+α (In the formula, M 1 and M 2 are each independently one or more elements other than Li, Ni, Co, Mn, and O, 0.9 ≤ x ≤ 1.2, 0 ≤ y ≤ 0.4, 0 ≤ z ≤ 0.4, 0 ≤ w ≤ 0.1, 0 < v ≤ 0.1, -1.0 ≤ α ≤ 0.5), and M 2The ratio of the total amount of Ni, Co and Mn in terms of substance amount to the total amount of M 2 The ratio of the total amount of Ni, Co and Mn to the total amount of Ni, Co and Mn converted into substance amount is 0.90 or more.

[0032] Here, "M 2 The ratio of the total amount of Ni, Co and Mn converted into substance amount is M 2 The formula is expressed as the total amount of Ni / (total amount of Co+total amount of Mn). 2 It is sometimes abbreviated as "percentage of."

[0033] M at 1 μm from the surface 2 at the particle center to the ratio of M 2 The ratio of M at 1 μm from the surface is not particularly limited as long as it is 0.90 or more, but is preferably 0.91 or more, 0.92 or more, 0.93 or more, 0.94 or more, or 0.95 or more. 2 at the particle center to the ratio of M 2 The ratio of M may be 5 or less, 3 or less, 2.5 or less, 2 or less, 1.7 or less, 1.5 or less, 1.2 or less, or 1.1 or less. 2 at the particle center to the ratio of M 2 The method for calculating the ratio is in accordance with the method shown in the Examples below.

[0034] element M 2 The element M is not particularly limited as long as it is one or more elements other than Li, Ni, Co, Mn, and O, and examples thereof include Al, Mg, Zn, Nb, W, Mo, Sb, V, Cr, Ca, Fe, Ga, Sr, Y, Ru, In, Sn, Ta, Bi, Zr, and B. In one embodiment, the element M 2 It is preferable to use W as the metal.

[0035] The activated lithium metal composite oxide powder preferably contains secondary particles having a distance from the surface to the particle center of 10 μm or more. The "distance from the surface to the particle center" refers to the shortest distance from each point on the surface (on the particle outline) to the particle center (geometric center) when the activated lithium metal composite oxide powder is observed with a scanning electron microscope.

[0036] <Method for producing activated lithium metal composite oxide> The method for producing an activated lithium metal composite oxide according to an embodiment of the present disclosure comprises the steps of: 1 and independently, one or more elements M other than Li, Ni, Co, Mn and O. 2 and a firing step of firing the raw material mixture in an oxidizing atmosphere.

[0037] The activated lithium metal composite oxide obtained in this manner exhibits superior cycle characteristics and lower resistance when used as a positive electrode active material in non-aqueous electrolyte secondary batteries, including lithium ion secondary batteries. The reason for this is not yet clear, and is not necessarily limited to a specific theory, but the present inventors believe it to be as follows. In the method for producing an activated lithium metal composite oxide according to this embodiment, the lithium metal composite oxide described in the previous section is used, and this lithium metal composite oxide has a cumulative pore volume of 25 μL / g or more in the pore diameter range of 25 nm to 334 nm. An activated lithium metal composite oxide having such a large cumulative pore volume allows element M to escape from its pores. 2 It incorporates compounds containing element M, making it easier for them to reach the inside of the particle. 2 The additive elements are expected to have the effects of suppressing the elution of transition metals on the active material surface during cycling, improving electronic conductivity, reducing charge transfer resistance during lithium intercalation / deintercalation, and suppressing sintering of primary particles during firing. However, it is thought that these effects are achieved by sufficiently penetrating the secondary particles, thereby improving cycle characteristics and reducing resistance.

[0038] Specifically, the method for producing the activated lithium metal composite oxide can include the following steps. Precursor preparation step: A precursor complex compound containing at least nickel is prepared. Precursor mixing step: A precursor mixture is prepared by mixing the precursor composite compound prepared in the precursor preparation step with a lithium compound. Primary firing step: If necessary, the precursor mixture prepared in the precursor mixing step is fired. Mixing step: Mixing at least the lithium metal composite oxide as the primary fired product obtained in the primary firing step and the element M 2 and optionally a lithium compound. Secondary firing step (which refers to the aforementioned "firing step", but for convenience, will be referred to as the "secondary firing step" here to distinguish it from the primary firing step): The raw material mixture prepared in the mixing step is fired. Water washing step: If necessary, the activated lithium metal composite oxide obtained by firing in the secondary firing step is subjected to a water washing treatment. Surface treatment step: If necessary, the activated lithium metal composite oxide obtained in the secondary firing step or water washing step is subjected to a surface treatment.

[0039] [Precursor preparation step] First, a precursor composite compound containing at least nickel is synthesized. In one embodiment, it can be obtained as an aggregate of primary particles. The method for synthesizing the precursor composite compound is not particularly limited, and examples include a method in which an aqueous solution containing an aqueous solution of a transition metal such as nickel and various aqueous solutions of compounds containing other elements according to the composition of the target lithium metal composite oxide is dropped into a reaction vessel in which an aqueous alkaline solution such as a sodium hydroxide solution or an ammonia solution is stirred as a mother liquid, and while also dropping sodium hydroxide or the like, the pH is monitored and controlled to be within an appropriate range, and co-precipitation is carried out by a wet reaction to obtain, for example, a hydroxide, an oxide obtained by calcining the hydroxide, a carbonate, or the like.

[0040] In the synthesis reaction, after preparing the aqueous alkaline solution to serve as the mother liquid, it is preferable to create a nitrogen atmosphere in the reaction tank using an inert gas, or industrially preferably nitrogen gas, to reduce the oxygen concentration in the reaction tank system and in the solution. If the oxygen concentration is too high, there is a risk that the coprecipitated hydroxide may be excessively oxidized by a predetermined amount or more of remaining oxygen, or that the formation of aggregates by crystallization may be hindered.

[0041] The aqueous solution of the transition metal is not particularly limited, but for example, an acidic aqueous solution is preferably used, and in the case of a nickel compound, it is more preferable to use an aqueous sulfuric acid solution such as an aqueous nickel sulfate solution. In addition, one or more kinds of aqueous solutions of the transition metal can be used.

[0042] The nickel compound is not particularly limited, but for example, one or more selected from nickel sulfate, nickel oxide, nickel hydroxide, nickel nitrate, nickel carbonate, nickel chloride, nickel iodide, metallic nickel, and the like can be used.

[0043] The cobalt compound is not particularly limited, but for example, one or more compounds selected from cobalt sulfate, cobalt oxide, cobalt hydroxide, cobalt nitrate, cobalt carbonate, cobalt chloride, cobalt iodide, and metallic cobalt can be used.

[0044] The manganese compound is not particularly limited, but for example, one or more compounds selected from manganese sulfate, manganese oxide, manganese hydroxide, manganese nitrate, manganese carbonate, manganese chloride, manganese iodide, and manganese metal can be used.

[0045] In the formula, element M 1 The element M is not particularly limited as long as it is one or more elements other than Li, Ni, Co, Mn, and O, and examples thereof include Al, Mg, Zn, Nb, W, Mo, Sb, V, Cr, Ca, Fe, Ga, Sr, Y, Ru, In, Sn, Ta, Bi, Zr, and B. Hereinafter, the element M will be referred to as 1 Specific examples of compounds containing the following will be described.

[0046] The titanium compound is not particularly limited, but for example, one or more compounds selected from titanyl sulfate, titanium oxide, titanium hydroxide, titanium nitrate, titanium carbonate, titanium chloride, titanium iodide, and metallic titanium can be used.

[0047] The aluminum compound is not particularly limited, but examples thereof include aluminum sulfate, aluminum oxide, aluminum hydroxide, aluminum nitrate, aluminum carbonate, aluminum chloride, aluminum iodide, sodium aluminate, and metallic aluminum.

[0048] The iron compound is not particularly limited, but for example, one or more selected from iron sulfate, iron oxide, iron hydroxide, iron nitrate, iron carbonate, iron chloride, iron iodide, metallic iron, and the like can be used.

[0049] The niobium compound is not particularly limited, but for example, one or more compounds selected from niobium oxide, niobium chloride, lithium niobate, niobium iodide, and the like can be used.

[0050] The tungsten compound is not particularly limited, but for example, one or more compounds selected from tungsten oxide, sodium tungstate, ammonium paratungstate, tungsten hexacarbonyl, tungsten sulfide, and the like can be used.

[0051] The magnesium compound is not particularly limited, but for example, one or more compounds selected from magnesium sulfate, magnesium oxide, magnesium hydroxide, magnesium nitrate, magnesium carbonate, magnesium chloride, magnesium iodide, and metallic magnesium can be used.

[0052] The zirconium compound is not particularly limited, but for example, one or more compounds selected from zirconium sulfate, zirconium oxide, zirconium nitrate, ammonium zirconium carbonate, zirconium chloride, zirconium iodide, and metallic zirconium can be used.

[0053] As for other elements, one or more selected from sulfates, oxides, hydroxides, nitrates, carbonates, chlorides, iodides, metals, and the like can be used.

[0054] The mixing ratio of each compound may be adjusted so that the amount of each element is in a desired ratio, taking into consideration the composition of the desired lithium metal composite oxide.

[0055] The appropriate pH range for synthesizing the precursor complex compound is not particularly limited and can be determined so as to obtain the desired secondary particle size and shape, such as the degree of coarseness and density, and is generally in the range of about 10 to 13.

[0056] The precursor composite compound obtained by the wet reaction is preferably subjected to a washing treatment, dehydrated, and then dried.

[0057] By subjecting the precursor composite compound to a washing treatment, impurities such as sulfate groups, carbonate groups, and sodium that have been incorporated into the aggregated particles or attached to the surface during the reaction can be washed away. For small amounts of the washing, a Nutsche washing method using a Buchner funnel can be used, or a method in which the suspension after the reaction is sent to a press filter for washing and dehydration can be used. For example, pure water, an aqueous sodium hydroxide solution, an aqueous sodium carbonate solution, etc. can be used in the washing treatment, but pure water is preferred for industrial use. However, if a large amount of residual sulfate groups remains, an aqueous sodium hydroxide solution with its pH adjusted according to the amount of residual sulfate groups can also be used.

[0058] [Precursor mixing process] Next, the precursor composite compound thus synthesized and a lithium compound are mixed in a predetermined ratio to prepare a precursor mixture. The mixing may be a solvent-based mixing in which the precursor composite compound and the lithium compound are each made into solutions such as aqueous solutions and these solutions are mixed in a predetermined ratio, or a non-solvent-based mixing in which a powder of the precursor composite compound and a powder of the lithium compound are weighed out to give a predetermined ratio and then mixed together in a dry state.

[0059] The lithium compound is not particularly limited, and various lithium salts can be used. Specifically, the lithium compound can be at least one selected from anhydrous lithium hydroxide, lithium hydroxide hydrate, lithium nitrate, lithium carbonate, lithium acetate, lithium bromide, lithium chloride, lithium citrate, lithium fluoride, lithium iodide, lithium lactate, lithium oxalate, lithium phosphate, lithium pyruvate, lithium sulfate, and lithium oxide. Among these, it is preferable to use at least one selected from anhydrous lithium hydroxide and lithium hydroxide hydrate.

[0060] The blending ratio of the lithium compound and the precursor composite compound is not particularly limited, but may be adjusted appropriately so that the amount of lithium and the total amount of each element are in the desired ratio, taking into consideration the composition of the desired lithium metal composite oxide.

[0061] [Primary firing process] In the mixing step described below, a lithium metal composite oxide having a cumulative pore volume of 25 μL / g or more in the pore diameter range of 25 nm to 334 nm is used, and this cumulative pore volume can be adjusted by the temperature of the primary firing. Therefore, it is preferable to perform primary firing in order to obtain a lithium metal composite oxide having a cumulative pore volume of 25 μL / g or more in the pore diameter range of 25 nm to 334 nm. However, the primary firing step is not an essential step.

[0062] In addition, the secondary firing step described below is generally performed by weighing out a lithium compound, a precursor compound, and optionally compounds of other elements, mixing them in a mixer, and then filling the resulting mixed powder into a container such as a crucible or a sagger. However, particularly during the lithiation reaction, it becomes difficult to vent the generated gas to the outside and to diffuse the necessary oxygen concentration, especially toward the bottom of the container where the mixed powder is filled. As a result, it becomes difficult to control the uniformity of the reaction and the primary particle size. From this perspective, it is preferable to perform primary firing.

[0063] In this primary firing step, it is preferable to adopt a firing method that particularly promotes the lithiation reaction. Specifically, a method can be used that makes the precursor mixture more susceptible to heat, easily expels gas generated from the lithium compound, and diffuses gas with a high oxygen partial pressure into the precursor mixture (particles). For example, it is possible to achieve the desired properties by firing a smaller amount of precursor mixture.

[0064] In the primary firing step, the precursor mixture can be filled into a sagger or a crucible and fired in a stationary furnace, a roller hearth kiln, or a pusher furnace. However, it is preferable to fire the precursor mixture while flowing it, and in that case, a rotary kiln can be used as the firing apparatus.

[0065] The temperature for the primary firing is not particularly limited, but is preferably, for example, 350°C or higher, 360°C or higher, 370°C or higher, 380°C or higher, or 390°C or higher. On the other hand, the temperature for the primary firing is preferably 650°C or lower, 640°C or lower, 630°C or lower, 620°C or lower, or 610°C or lower. In particular, when controlling the cumulative pore volume, this can be adjusted by the chemical composition, surface state, pore state, particle size, etc. of the precursor composite compound and lithium compound, and the temperature can be in the range of less than 350°C or more than 650°C.

[0066] The time for the primary baking is not particularly limited as long as the lithiation reaction proceeds reliably and uniformly, but is preferably, for example, 1 to 10 hours, or 2 to 8 hours.

[0067] In this disclosure, the baking temperature is the maximum temperature when the object to be heated is heated. The maximum temperature refers to the temperature of the hottest part of the object to be heated. The baking time refers to the time during which the baking temperature reaches a predetermined range and remains within that range. The same definitions of baking temperature and baking time apply hereinafter.

[0068] The atmosphere for the primary firing is not particularly limited as long as it is an oxidizing atmosphere in which the lithiation reaction proceeds reliably and uniformly. For example, it is preferable to use a decarbonated oxidizing gas atmosphere with a carbon dioxide concentration of 30 ppm or less, or an oxygen atmosphere with an oxygen concentration of 80 vol% or more, 85 vol% or more, 90 vol% or more, or 95 vol% or more.

[0069] The fired product thus obtained is subjected to crystal growth and particle growth at a higher temperature, and the element M 2 In order to distribute the catalyst throughout the lithium metal composite oxide, a secondary baking is carried out in a later step.

[0070] If the lithium metal composite oxide obtained by the primary firing is in the form of agglomerates, it may be pulverized using a grinder or a mortar.

[0071] [Mixing process] In the present disclosure, at least a lithium metal composite oxide and an element M 2 The compound containing element M is mixed with a lithium compound, if necessary. The amount and method of the compound to be added may be the same as those described in the precursor preparation step. 2 The compound containing element M described in the precursor preparation process 1 Furthermore, the compound may be the same as a compound containing the element M 1 and element M 2 and may be the same element or different elements.

[0072] Specifically, element M 2 The element is not particularly limited as long as it is one or more elements other than Li, Ni, Co, Mn, and O, but examples that can be used include Al, Mg, Zn, Nb, W, Mo, Sb, V, Cr, Ca, Fe, Ga, Sr, Y, Ru, In, Sn, Ta, Bi, Zr, and B.

[0073] Also, element M 2 As the compound containing the above, one or more compounds selected from sulfates, oxides, hydroxides, nitrates, carbonates, chlorides, iodides, metals, and the like can be used.

[0074] In the mixing step, for example, when the amount of lithium used in the raw material mixing step is less than the amount of the desired lithium metal composite oxide, a lithium compound may be further added as necessary.

[0075] The lithium compound is not particularly limited, and the same lithium salts as those usable in the raw material mixing step can be used. Specifically, the lithium compound can be, for example, one or more selected from anhydrous lithium hydroxide, lithium hydroxide hydrate, lithium nitrate, lithium carbonate, lithium acetate, lithium bromide, lithium chloride, lithium citrate, lithium fluoride, lithium iodide, lithium lactate, lithium oxalate, lithium phosphate, lithium pyruvate, lithium sulfate, and lithium oxide. Among these, it is preferable to use one or more selected from anhydrous lithium hydroxide and lithium hydroxide hydrate. It is not necessary to use the same lithium compound as that used in the raw material mixing step.

[0076] [Secondary firing process] In the secondary firing, the lithium metal composite oxide contained in the raw material mixture undergoes a lithiation reaction and crystal growth. The lithiation reaction requires a certain oxygen partial pressure. The lithiation reaction produces an activated lithium metal composite oxide containing lithium. The temperature is then raised to a predetermined temperature to promote crystal growth.

[0077] The secondary firing temperature is not particularly limited as long as it is higher than the primary firing temperature, and can be adjusted depending on the composition of the activated lithium metal composite oxide to be obtained. For example, the firing temperature is preferably 700°C or higher, 710°C or higher, 720°C or higher, 730°C or higher, 740°C or higher, or 750°C or higher. On the other hand, the secondary firing temperature is preferably 1100°C or lower, 1070°C or lower, 1050°C or lower, 1020°C or lower, 1000°C or lower, 970°C or lower, 950°C or lower, 920°C or lower, 900°C or lower, 870°C or lower, 850°C or lower, 820°C or lower, or 800°C or lower. By keeping the secondary firing temperature within the required range, an activated lithium metal composite oxide having a desired crystal structure can be obtained. Furthermore, unreacted components can be reduced, and a deterioration in the battery characteristics of a nonaqueous electrolyte secondary battery using the obtained activated lithium metal composite oxide as a positive electrode can be prevented.

[0078] The time for secondary baking is not particularly limited as long as it is long enough to form an activated lithium metal composite oxide having a desired crystal structure, and is preferably, for example, 1 to 15 hours, 2 to 12 hours, or 2 to 10 hours.

[0079] The atmosphere for the secondary firing is not particularly limited, as long as it ensures reliable and uniform crystal growth, has an oxygen partial pressure that does not reduce the transition metals contained in the raw material mixture to be fired, and preferably has a low moisture content and carbon dioxide concentration. For example, it is preferable to use a decarbonated oxidizing gas atmosphere with a carbon dioxide concentration of 30 ppm or less, or an oxygen atmosphere with an oxygen concentration of preferably 80 vol% or more, or 90 vol% or more.

[0080] [Water washing process] The activated lithium metal composite oxide obtained in the secondary firing step may contain impurities such as unreacted lithium compounds and lithium compounds that appear on the particle surface due to the crystalline structure during the primary and secondary firing steps. Therefore, in order to remove or reduce these impurities, the oxide may be subjected to, for example, water washing and heat treatment. Note that the water washing step is not an essential step.

[0081] [Surface treatment process] By adding and mixing a compound of a predetermined element to the activated lithium metal composite oxide obtained in the secondary firing step or the water washing step and then subjecting it to heat treatment, the surfaces of the primary particles and / or secondary particles of the activated lithium metal composite oxide can be surface-treated with a compound of lithium and the added element. This can achieve effects such as reducing the amount of lithium compounds remaining on the particle surface, improving lithium ion conductivity, and reducing reaction resistance. Note that the surface treatment step is not an essential step.

[0082] The element compound added for the above-mentioned surface treatment can be selected from, for example, aluminum compounds, boron compounds, tungsten compounds, manganese compounds, cobalt compounds, phosphorus compounds, niobium compounds, strontium compounds, antimony compounds, zirconium compounds, titanium compounds, etc., and one or more of these compounds can be used.

[0083] The heat treatment temperature is not particularly limited, but is preferably, for example, 200° C. or higher, 210° C. or higher, 220° C. or higher, 230° C. or higher, 240° C. or higher, or 250° C. On the other hand, the heat treatment temperature is preferably 500° C. or lower, 490° C. or lower, 480° C. or lower, 470° C. or lower, 460° C. or lower, 450° C. or lower, 440° C. or lower, 430° C. or lower, 420° C. or lower, 410° C. or lower, or 400° C. or lower.

[0084] The heat treatment time is not particularly limited, and is preferably, for example, 1 hour to 15 hours, 2 hours to 12 hours, or 2 hours to 10 hours.

[0085] ≪Nonaqueous electrolyte secondary battery≫ The nonaqueous electrolyte secondary battery according to the embodiment of the present disclosure includes a positive electrode containing the above-described activated lithium metal composite oxide powder as a positive electrode active material for a nonaqueous electrolyte secondary battery, and the nonaqueous electrolyte secondary battery is composed of a positive electrode, a negative electrode, and an electrolytic solution containing an electrolyte.

[0086] When manufacturing a positive electrode, a conductive agent and a binder are added to and mixed with the activated lithium metal composite oxide powder according to the embodiment of the present disclosure. The conductive agent is preferably, for example, acetylene black, carbon black, graphite, or the like. The binder is preferably, for example, polytetrafluoroethylene, polyvinylidene fluoride, or the like.

[0087] The negative electrode is not particularly limited, and examples thereof include negative electrode active materials such as lithium metal, graphite, and low-crystalline carbon materials, as well as one or more nonmetallic or metallic elements selected from Si, Al, Sn, Pb, Zn, Bi, and Cd, alloys containing them, or chalcogen compounds containing them.

[0088] The solvent for the electrolytic solution is not particularly limited, but may be, for example, an organic solvent containing one or more selected from carbonates such as ethylene carbonate, propylene carbonate, dimethyl carbonate, and diethyl carbonate, and ethers such as dimethoxyethane.

[0089] As the electrolyte, in addition to lithium hexafluorophosphate (LiPF6), one or more selected from lithium salts such as lithium perchlorate and lithium tetrafluoroborate can be dissolved in a solvent and used.

[0090] Although specific examples of the embodiments of the present disclosure have been described above, modifications can be made as appropriate within the scope that does not impair the effects of the present invention. [Example]

[0091] The present disclosure will be described in more detail below with reference to examples, but the present disclosure is not limited to these examples.

[0092] <Preparation of activated lithium metal composite oxide powder sample> Activated lithium metal composite oxide powder samples of Examples 1 to 9 and Comparative Examples 1 to 12 were prepared by the methods described below.

[0093] Example 1 A mixed aqueous solution was obtained by mixing an aqueous nickel sulfate solution and an aqueous manganese sulfate solution so that the ratio (molar ratio) of Ni to Mn was Ni:Mn = 90:10. 10 L of pure water containing 300 g of sodium hydroxide solution and 500 g of ammonia water was prepared in advance in the reaction vessel as a mother liquid, and a nitrogen atmosphere was created in the reaction vessel by adding nitrogen gas at a flow rate of 0.7 L / min. The reaction was also carried out in a nitrogen atmosphere.

[0094] Then, while rotating the stirring blade at 600 rpm, the mixed aqueous solution, sodium hydroxide aqueous solution, and ammonia water were simultaneously added dropwise using a metering pump. The amount of alkaline solution added was adjusted so that the pH was 10.8, and a crystallization reaction was carried out. A coaxial nozzle with a double-tube structure equipped with an internal tube was installed in the reaction vessel, and the length of the raw material injection nozzle was set long so that the distance between the inlet of the raw material injection nozzle (internal tube) that injected the mixed solution of nickel sulfate and manganese sulfate and the inlet of the alkaline injection nozzle that injected the sodium hydroxide aqueous solution and ammonia water (nozzle inlet distance) was 1 mm, and the raw material was continuously added to the reaction mother liquor. During the crystallization reaction, the reaction slurry was sampled appropriately from the overflow pipe installed at the top of the reaction vessel, and the pH of the reaction slurry was confirmed to be stable at 10.8, after which the slurry was recovered.

[0095] The slurry was then subjected to solid-liquid separation and washed with pure water to reduce residual impurities. The coprecipitate cake was then dried at 100°C for 10 hours in an air environment to obtain the product with the formula Ni 0.90 Mn 0.10 The precursor complex compound 1 represented by (OH)2 was obtained.

[0096] Precursor composite compound 1 and lithium hydroxide were weighed and mixed so that Li / (Ni+Mn)=1.040, and then primary calcined at 400°C for 6 hours in an oxygen atmosphere (oxygen concentration: 97 vol%) to obtain a lithium metal composite oxide.

[0097] Next, the obtained lithium metal composite oxide and tungsten (VI) oxide were weighed and mixed so that W / (Ni+Mn)=0.5 mol%, and then secondary fired in an oxygen atmosphere (oxygen concentration: 97 vol%) at 800°C for 6 hours. The fired product was pulverized to obtain an activated lithium metal composite oxide powder sample of Example 1.

[0098] Example 2 An activated lithium metal composite oxide powder sample of Example 2 was obtained in the same manner as in Example 1, except that the primary firing was carried out at 500°C.

[0099] Example 3 An activated lithium metal composite oxide powder sample of Example 3 was obtained in the same manner as in Example 1, except that the primary firing was carried out at 600°C.

[0100] Comparative Example 1 An activated lithium metal composite oxide powder sample of Comparative Example 1 was obtained in the same manner as in Example 1, except that the primary firing was carried out at 700°C.

[0101] Comparative Example 2 An activated lithium metal composite oxide powder sample of Comparative Example 2 was obtained in the same manner as in Example 1, except that the primary firing was carried out at 800°C.

[0102] Comparative Example 3 The precursor composite compound, lithium hydroxide, and tungsten (VI) oxide were weighed and mixed so that Li / (Ni+Mn) = 1.040 and W / (Ni+Mn) = 0.5 mol%, respectively. After that, the mixture was first baked at 570°C for 6 hours in an oxygen atmosphere (oxygen concentration: 97 vol%) to obtain a lithium metal composite oxide.

[0103] The obtained lithium metal composite oxide was then subjected to secondary firing in an oxygen atmosphere (oxygen concentration: 97 vol%) at 800° C. for 6 hours. The fired product was pulverized to obtain an activated lithium metal composite oxide powder sample of Comparative Example 3.

[0104] Example 4 A mixed aqueous solution was obtained by mixing an aqueous nickel sulfate solution, a cobalt sulfate solution, and an aqueous manganese sulfate solution so that the molar ratio of Ni to Co to Mn was Ni:Co:Mn = 90:5:5. 10 L of pure water containing 300 g of sodium hydroxide solution and 500 g of ammonia water was prepared in advance in the reaction vessel as a mother liquor. The reaction vessel was filled with nitrogen gas at a flow rate of 0.7 L / min to create a nitrogen atmosphere, and the reaction was also carried out in a nitrogen atmosphere.

[0105] Then, while rotating the stirring blade at 600 rpm, the mixed aqueous solution, sodium hydroxide aqueous solution, and ammonia water were simultaneously added dropwise using a metering pump, and the amount of alkaline solution added was adjusted so that the pH was 11.4, and a crystallization reaction was carried out. A coaxial nozzle with a double-tube structure equipped with an internal tube was installed in the reaction vessel, and the length of the raw material injection nozzle was set long so that the distance between the inlet of the raw material injection nozzle (internal tube) for injecting a solution containing nickel sulfate, cobalt sulfate, and manganese sulfate and the inlet of the alkaline injection nozzle for injecting the sodium hydroxide aqueous solution and ammonia water (nozzle inlet distance) was 15 mm, and the raw material was continuously added to the reaction mother liquor. During the crystallization reaction, the reaction slurry was sampled appropriately from the overflow pipe installed at the top of the reaction vessel, and after confirming that the pH of the reaction slurry was stable at 11.4, the slurry was recovered.

[0106] The slurry was then subjected to solid-liquid separation and washed with pure water to reduce residual impurities. The coprecipitate cake was then dried at 100°C for 10 hours in an air environment to obtain the product with the formula Ni 0.90 Co 0.05 Mn 0.05 The precursor complex compound 2 represented by (OH)2 was obtained.

[0107] Precursor composite compound 2 and lithium hydroxide were weighed and mixed so that Li / (Ni+Co+Mn) = 1.040, and then primary calcined at 400°C for 6 hours in an oxygen atmosphere (oxygen concentration: 97 vol%) to obtain a lithium metal composite oxide.

[0108] Next, the obtained lithium metal composite oxide after primary firing and tungsten (VI) oxide were weighed and mixed so that W / (Ni+Mn)=0.5 mol%, and then primary firing was performed for 6 hours at 800°C in an oxygen atmosphere (oxygen concentration: 97 vol%). The obtained fired product was pulverized to obtain an activated lithium metal composite oxide sample of Example 4.

[0109] Example 5 An activated lithium metal composite oxide powder sample of Example 5 was obtained in the same manner as in Example 4, except that the primary firing was carried out at 500°C.

[0110] Comparative Example 4 An activated lithium metal composite oxide powder sample of Comparative Example 4 was obtained in the same manner as in Example 4, except that the primary firing was carried out at 600°C.

[0111] Comparative Example 5 An activated lithium metal composite oxide powder sample of Comparative Example 5 was obtained in the same manner as in Example 4, except that the primary firing was carried out at 700°C.

[0112] Comparative Example 6 An activated lithium metal composite oxide powder sample of Comparative Example 6 was obtained in the same manner as in Example 4, except that the primary firing was carried out at 800°C.

[0113] Comparative Example 7 Precursor composite compound 2, lithium hydroxide, and tungsten (VI) oxide were weighed and mixed so that Li / (Ni+Co+Mn) = 1.040 and W / (Ni+Co+Mn) = 0.5 mol%, and then primary calcined at 570°C for 6 hours in an oxygen atmosphere (oxygen concentration: 97 vol%) to obtain a lithium metal composite oxide.

[0114] The obtained lithium metal composite oxide was then subjected to secondary firing in an oxygen atmosphere (oxygen concentration: 97 vol%) at 800° C. for 6 hours. The fired product was pulverized to obtain an activated lithium metal composite oxide powder sample of Comparative Example 7.

[0115] Example 6 A lithium metal composite oxide was obtained in the same manner as in Example 3. This lithium metal composite oxide and aluminum hydroxide were weighed and mixed so that Al / (Ni+Mn) = 1.0 mol%, and then secondary fired in an oxygen atmosphere (oxygen concentration: 97 vol%) at 780°C for 6 hours. The fired product was pulverized to obtain an activated lithium metal composite oxide powder sample of Example 6.

[0116] Comparative Example 8 Precursor composite compound 1, lithium hydroxide, and aluminum hydroxide were weighed and mixed so that Li / (Ni+Mn)=1.040 and Al / (Ni+Mn)=1.0 mol%, and then primary calcined at 600°C for 6 hours in an oxygen atmosphere (oxygen concentration: 97 vol%) to obtain a lithium metal composite oxide of Comparative Example 8.

[0117] Next, the obtained lithium metal composite oxide after the primary firing was subjected to secondary firing for 6 hours at 780°C in an oxygen atmosphere (oxygen concentration: 97 vol%). The obtained fired product was pulverized to obtain an activated lithium metal composite oxide powder sample of Comparative Example 8.

[0118] Example 7 A lithium metal composite oxide was obtained in the same manner as in Example 3. This lithium metal composite oxide after primary firing and titanium oxide were weighed and mixed so that Ti / (Ni+Mn) = 1.0 mol%, and then secondary firing was performed in an oxygen atmosphere (oxygen concentration: 97 vol%) at 780°C for 6 hours. The obtained fired product was pulverized to obtain an activated lithium metal composite oxide powder sample of Example 7.

[0119] Comparative Example 9 Precursor composite compound 1, lithium hydroxide, and titanium oxide were weighed and mixed so that Li / (Ni+Mn)=1.040 and Ti / (Ni+Mn)=1.0 mol%, and then primary calcined at 600°C for 6 hours in an oxygen atmosphere (oxygen concentration: 97 vol%) to obtain a lithium metal composite oxide of Comparative Example 9.

[0120] The obtained lithium metal composite oxide was then subjected to secondary firing in an oxygen atmosphere (oxygen concentration: 97 vol%) at 780° C. for 6 hours. The fired product was pulverized to obtain an activated lithium metal composite oxide powder sample of Comparative Example 9.

[0121] Example 8 A lithium metal composite oxide sample was obtained in the same manner as in Example 3. Next, the obtained lithium metal composite oxide and niobium (V) oxide were weighed and mixed so that Nb / (Ni+Mn) = 0.2 mol%, and then secondary fired in an oxygen atmosphere (oxygen concentration: 97 vol%) at 780°C for 6 hours. The fired product was pulverized to obtain an activated lithium metal composite oxide powder sample of Example 8.

[0122] Comparative Example 10 Precursor composite compound 1, lithium hydroxide, and niobium (V) oxide were weighed and mixed so that Li / (Ni+Mn)=1.040 and Nb / (Ni+Mn)=0.2 mol%, and then primary calcined at 600°C for 6 hours in an oxygen atmosphere (oxygen concentration: 97 vol%) to obtain a lithium metal composite oxide of Comparative Example 10.

[0123] The obtained lithium metal composite oxide was then subjected to secondary firing in an oxygen atmosphere (oxygen concentration: 97 vol%) at 780° C. for 6 hours. The fired product was pulverized to obtain an activated lithium metal composite oxide powder sample of Comparative Example 10.

[0124] Example 9 A lithium metal composite oxide was obtained in the same manner as in Example 3. Next, the obtained lithium metal composite oxide and zirconium oxide were weighed and mixed so that Zr / (Ni+Mn)=1.0 mol%, and then secondary fired in an oxygen atmosphere (oxygen concentration: 97 vol%) at 780°C for 6 hours. The fired product was pulverized to obtain an activated lithium metal composite oxide powder sample of Example 9.

[0125] Comparative Example 11 Precursor composite compound 1, lithium hydroxide, and zirconium oxide were weighed and mixed so that Li / (Ni+Mn)=1.040 and Zr / (Ni+Mn)=1.0 mol%, and then primary calcined at 600°C for 6 hours in an oxygen atmosphere (oxygen concentration: 97 vol%) to obtain a lithium metal composite oxide of Comparative Example 11.

[0126] The obtained lithium metal composite oxide was then subjected to secondary firing in an oxygen atmosphere (oxygen concentration: 97 vol%) at 780° C. for 6 hours. The fired product was pulverized to obtain an activated lithium metal composite oxide powder sample of Comparative Example 11.

[0127] <Evaluation method> [Composition analysis of precursor complex compounds] The composition of the precursor composite compound was determined by the following method. 0.2 g of sample was heated and dissolved in 25 ml of 20% hydrochloric acid solution, cooled, and then transferred to a 100 ml measuring flask. Pure water was added to prepare a solution. The elements in the obtained solution were quantified using ICP-AES (Optima 8300, manufactured by PerkinElmer Japan Co., Ltd.).

[0128] [Measurement of cumulative pore volume of precursor composite compound and lithium metal composite oxide after primary firing] The cumulative pore volume of the lithium metal composite oxide after primary firing was measured after it had been washed with water and dried in advance. Specifically, the lithium metal composite oxide after primary firing was mixed with pure water adjusted to a liquid temperature of 25°C at a ratio of 200 g / L to produce a slurry. The slurry was stirred for 10 minutes and then dehydrated to obtain a cake-like compound. The cake-like compound was dried in a vacuum dryer at 75°C for 2 hours and then at 120°C for 10 hours, and used for various evaluations.

[0129] The cumulative pore volume of the precursor composite compound and the lithium metal composite oxide after the primary firing with a pore diameter of 25 to 336 nm was determined using mercury intrusion porosimetry. The pore diameter was calculated using the Washburn equation.

[0130] (Mercury porosimetry measurement conditions) Measurement device: Autopore V9620 (manufactured by Micrometritics) Surface tension of mercury: 480 dynes / cm Contact angle between mercury and sample: 140 degrees

[0131] [Battery characteristic evaluation using coin cells with positive electrode active material samples] A 2032-type coin cell using the positive electrode active material particles was manufactured using a positive electrode, a negative electrode, and an electrolyte solution prepared by the following methods.

[0132] (positive electrode) Acetylene black and graphite were used as conductive agents in a weight ratio of 1:1, and polyvinylidene fluoride was used as a binder. The positive electrode active material, conductive agent, and binder were blended in a weight ratio of 90:6:4, and these were mixed with N-methylpyrrolidone. The mixture was applied to aluminum foil. This was dried at 110°C to produce a sheet, which was then punched into a 15 mm diameter sheet and then coated with a 3 t / cm 2 The resultant was rolled to form a positive electrode.

[0133] (Negative electrode) A lithium foil with a thickness of 500 μm and punched to 16 mm diameter was used as the negative electrode.

[0134] (electrolyte) A mixed solvent of EC and DMC was prepared so that the volume ratio of EC:DMC was 1:2, and the electrolyte was mixed with 1 mol / L of LiPF6 to prepare an electrolyte solution.

[0135] (Reaction resistance of non-aqueous electrolyte secondary battery) Using the coin cell manufactured by the above method, constant current charging was performed at a current density of 0.1 C rate to a voltage of 4.3 V in an environment of 25°C. After reaching 4.3 V, constant voltage charging was performed until the current density reached 0.01 C rate. After a 5-minute pause, constant current discharging was performed at a current density of 0.1 C rate to a voltage of 3.0 V in the same environment. After another 5-minute pause, constant current charging was performed at a current density of 0.1 C rate to a voltage of 4.3 V in the same environment. After reaching 4.3 V, constant voltage charging was performed until the current density reached 0.01 C rate, and then a 5-minute pause was performed. Impedance measurements were then performed under the following conditions, and the reaction resistance was calculated. Impedance measurement device: [Solartron 1400 type & FRA type 1470, manufactured by Solartron] Measurement environment: 25°C Coin Cell: Half Cell Measurement voltage: 4.3V Applied voltage: 10mV Scanning frequency: 1M~0.01Hz

[0136] (Cycle characteristics of non-aqueous electrolyte secondary batteries) A cycle test was carried out using the coin cell manufactured by the above-mentioned method. 1. First charge / discharge In an environment of 60°C, constant current charging was performed at a current density of 0.2C up to a voltage of 4.3V, and after reaching 4.3V, constant voltage charging was performed until the rate reached 0.01C. Next, after a 5-minute pause, constant current discharging was performed in the same environment at a current density of 0.2C from 4.3V to 3.0V. Next, after a 5-minute pause, constant current charging was performed in the same environment at a current density of 0.1C up to a voltage of 4.3V, and after reaching 4.3V, constant voltage charging was performed until the rate reached 0.01C, and then a 5-minute pause was performed.

[0137] 2. Cycle test In a 60°C environment, the battery was charged at a constant current density of 0.5 C up to a voltage of 4.3 V, and after reaching 4.3 V, it was charged at a constant voltage down to a rate of 0.01 C. After a 5-minute break, it was discharged at a constant current density of 1.0 C up to a voltage of 3.0 V in the same environment, and then a 5-minute break was repeated 100 times. The cycle characteristics were then calculated based on the following equation. Cycle characteristics (%) = [(100th discharge capacity) / (1st discharge capacity)] × 100

[0138] [Addition element M of the positive electrode active material sample 2 Uniformity within secondary particles The uniformity of the added element D within the secondary particles of the positive electrode active material sample was evaluated as follows.

[0139] (Cross-sectional SEM-EDX measurement of secondary particles) Cross sections of the secondary particles were prepared using a cross section polisher (SM-09010) manufactured by JEOL Ltd. at an acceleration voltage of 6 kV.

[0140] Using a field emission scanning electron microscope (JSM-7100F, manufactured by JEOL Ltd.), cross-sectional SEM-EDX measurement of the secondary particles was carried out at an acceleration voltage of 20 kV. First, quantitative analysis was carried out at a point 1 μm away from the outermost surface of the secondary particles toward the center of gravity of the cross section. 2 From the atomic weight ratio of Ni, Co, and Mn, the added element M at a point 1 μm away from the outermost surface of the secondary particle 2 Then, quantitative analysis was performed at the center of gravity of the cross section, and the obtained additive element M 2 From the atomic weight ratio of Ni, Co, and Mn, the added element M at the point farthest from the outermost surface of the secondary particle 2 / (Ni+Co+Mn) was calculated.

[0141] The above SEM-EDX measurement was carried out on 100 secondary particles with a major axis of 20 μm or more, and the added element M at a point 1 μm away from the outermost surface of the secondary particles was measured. 2 / (Ni+Co+Mn) 100 average values ​​are added element M on the secondary particle surface. 2 / (Ni+Co+Mn) is A, and the added element M is the point furthest from the outermost surface of the secondary particle. 2 / (Ni+Co+Mn) 100 average values ​​are added element M at the center of secondary particles 2 / (Ni+Co+Mn) was calculated as B.

[0142] Next, the additive element M 2 As an index for judging the uniformity within the secondary particles, the value (B / A) obtained by dividing B by A was calculated.

[0143] <Evaluation results> The above-mentioned evaluations were carried out for Examples 1 to 3 and Comparative Examples 1 to 3. The results are shown in Table 1.

[0144] [Table 1]

[0145] The above-mentioned evaluations were carried out for Examples 4 to 9 and Comparative Examples 4 to 11. The results are shown in Table 2. Although B / A is not shown in the table, the activated lithium metal composite oxides of Examples 4 to 9 had a B / A of 0.9 or more, while the activated lithium metal composite oxides of Comparative Examples 4 to 11 had a B / A of less than 0.90.

[0146] [Table 2]

Claims

1. General formula Li ｘ Ni １－ｙ－ｚ－ｗ Co ｙ Mn ｚ M １ ｗ O ２＋α (In the formula, M １ is one or more elements other than Li, Ni, Co, Mn, and O, and 0<x≦1.2, 0≦y≦0.4, 0≦z≦0.4, 0≦w≦0.1, −1.0≦α≦0.5), and the cumulative pore volume in the pore diameter range of 25 nm to 334 nm measured by mercury intrusion porosimetry is 25 μL / g or more. Lithium metal composite oxide.

2. At least the lithium metal composite oxide according to claim 1 and M １ and independently one or more elements M other than Li, Ni, Co, Mn and O. ２ a mixing step of mixing the compound containing the compound with the compound to obtain a raw material mixture; and a calcination step of calcining the raw material mixture in an oxidizing atmosphere. A method for producing activated lithium metal composite oxide.

3. In the mixing step, a lithium compound is further mixed. The method for producing the activated lithium metal composite oxide according to claim 2 .

4. An activated lithium metal composite oxide powder, General formula Li ｘ Ni １－ｙ－ｚ－ｗ－ｖ Co ｙ Mn ｚ M １ ｗ M ２ ｖ O ２＋α (In the formula, M １ and M ２ each independently represents one or more elements other than Li, Ni, Co, Mn, and O, and 0.9≦x≦1.2, 0≦y≦0.4, 0≦z≦0.4, 0≦w≦0.1, 0<v≦0.1, and −1.0≦α≦0.5; M at the particle center ２ The ratio of the total amount of Ni, Co and Mn in terms of substance amount to the total amount of M ２ The ratio of the total amount of Ni, Co and Mn to the total amount of Ni, Co and Mn in terms of substance amount is 0.90 or more. Activated lithium metal composite oxide powder.

5. M ２ is W The activated lithium metal composite oxide powder according to claim 4.

6. Contains secondary particles with a distance from the surface to the particle center of 10 μm or more 6. The activated lithium metal composite oxide powder according to claim 4 or 5.

7. The activated lithium metal composite oxide powder according to claim 4 or 5 is included. Positive electrode active material for non-aqueous electrolyte secondary batteries.

8. The positive electrode active material for a non-aqueous electrolyte secondary battery according to claim 7 is provided. Nonaqueous electrolyte secondary battery.

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