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EP-3960709-B1 - NICKEL COMPOSITE HYDROXIDE, METHOD FOR PRODUCING NICKEL COMPOSITE HYDROXIDE, POSITIVE ELECTRODE ACTIVE MATERIAL FOR LITHIUM ION SECONDARY BATTERY, METHOD FOR PRODUCING POSITIVE ELECTRODE ACTIVE MATERIAL FOR LITHIUM ION SECONDARY BATTERY, AND LITHIUM ION SECONDARY BATTERY

EP3960709B1EP 3960709 B1EP3960709 B1EP 3960709B1EP-3960709-B1

Inventors

  • YAMAUCHI, MITSURU
  • ITO, TAI
  • KOMUKAI, TETSUFUMI

Dates

Publication Date
20260506
Application Date
20200424

Claims (8)

  1. A nickel composite hydroxide, which is composed of secondary particles to which plural primary particles are aggregated, wherein the nickel composite hydroxide comprises nickel, cobalt, manganese, and an element M with an atomic ratio of Ni: Co: Mn: M = 1-x1-y1-z1: x1: y1; z1, wherein M is at least one element selected from a group consisting of a transition metal element other than Ni, Co, Mn, a II group element. and a XIII group element, 0.15 ≦x1 ≤0.25, 0.15≦y1≦0.25, 0≦z1≤0.1, the nickel composite hydroxide is having a cobalt rich layer or a manganese rich layer from a surface of a particle of the secondary particles toward an inside of the particle of the secondary particles and a layered low-density layer between the cobalt rich layer or the manganese rich layer and a center of the particle of the secondary particles, the cobalt rich layer comprises nickel, cobalt, manganese, and an element M with an atomic ratio of Ni: Co: Mn: M = 1-x2-y2-z2: x2: y2: z2, wherein M is at least one element selected from a group consisting of a transition metal element other than Ni, Co, Mn, a II group element, and a XIII group element, x2, y2 and z2 satisfy x2=1, y2=0 and z2=0, or x2/((1-x2-y2-z2)+y2)≧1, and z2 is within a range of 0 ≦ z2 ≦ 0.1, the manganese rich layer comprises nickel, cobalt, manganese, and an element M with an atomic ratio of Ni: Co: Mn: M = 1-x2-y2-z2: x2: y2: z2, wherein M is at least one element selected from a group consisting of a transition metal element other than Ni, Co, Mn, a II group element, and a XIII group element, x2, y2 and z2 satisfy x2=0, y2=1 and z2=0, or y2/((1-x2-y2-z2)+x2) 2 1, and z2 is within a range of 0 ≦ z2 ≦ 0.1, and a thickness of the cobalt rich layer or the manganese rich layer is 1% or more and 10% or less with respect to a diameter of the secondary particles, and also, a thickness of the low-density layer is 1% or more and 10% or less with respect to the diameter of the secondary particles.
  2. The nickel composite hydroxide according to claim 1, wherein, in a particle size distribution measured by a laser diffraction scattering method, a volume average particle size (Mv) is 4 micrometers or more and 10 micrometers or less, and [(D90-D10)/Mv] indicating a particle size distribution width, which is calculated by a cumulative 90 volume% particle size (D90) and a cumulative 10 volume% particle size (D10), and the volume average particle size (Mv), is 0.60 or less.
  3. A method for producing a nickel composite hydroxide, which is composed of secondary particles to which plural primary particles are aggregated, comprising: a nucleation process for performing a nucleation by adjusting a first mixed aqueous solution containing at least one of a nickel salt, a cobalt salt, and a manganese salt such that a pH will be 12.5 or more on the basis of a liquid temperature of 25°C, in a non-oxidizing atmosphere with an oxygen concentration of less than 5 volume%; and a particle growth process for performing a particle growth by adjusting a slurry containing nucleus formed in the nucleation process such that a pH will be in a range of 10.5 or more and 12.5 or less on the basis of a liquid temperature of 25°C, and also, a pH will be lower than the pH in the nucleation process, wherein the particle growth process comprises: a first particle growth process; a second particle growth process; and a third particle growth process for forming a cobalt rich layer or a manganese rich layer from a surface of a particle of the secondary particles toward an inside of the particle of the secondary particles, in the first particle growth process, a center of the particle is formed by supplying the first mixed aqueous solution to a mixed aqueous solution obtained in the nucleation process in a non-oxidizing atmosphere with an oxygen concentration of less than 5 volume%, in the second particle growth process, a layered low-density layer is formed by supplying the first mixed aqueous solution to a mixed aqueous solution obtained in the first particle growth process, and by switching to an oxidizing atmosphere with an oxygen concentration of 5 volume% or more, in the third particle growth process for forming the cobalt rich layer, the cobalt rich layer is formed by supplying a second mixed aqueous solution comprising nickel, cobalt, manganese, and an element M with an atomic ratio of Ni: Co: Mn: M = 1-x2-y2-z2: x2: y2: z2, wherein M is at least one element selected from a group consisting of a transition metal element other than Ni, Co, Mn, a II group element, and a XIII group element, x2, y2 and z2 satisfy x2=1, y2=0 and z2=0, or x2/((1-x2-y2-z2)+y2)≧1, and z2 is within a range of 0 ≦ z2 ≦ 0.1, to a mixed aqueous solution obtained in the second particle growth process, and by switching to a non-oxidizing atmosphere with an oxygen concentration of less than 5 volume%, or in the third particle growth process for forming the manganese rich layer, the manganese rich layer is formed by supplying a second mixed aqueous solution comprising nickel, cobalt, manganese, and an element M with an atomic ratio of Ni: Co: Mn: M = 1-x2-y2-z2: x2: y2: z2, wherein M is at least one element selected from a group consisting of a transition metal element other than Ni, Co, Mn, a II group element, and a XIII group element, x2, y2 and z2 satisfy x2=0, y2=1 and z2=0, or y2/((1-x2-y2-z2)+x2)≧1, and z2 is within a range of 0 ≦ 2 ≦ 0.1, to a mixed aqueous solution obtained in the second particle growth process, and by switching to a non-oxidizing atmosphere with an oxygen concentration of less than 5 volume%.
  4. The method for producing a nickel composite hydroxide according to claim 3, wherein, in the particle growth process, an ammonia adjusted to a concentration of 5 g/L or more and 20 g/L or less is added to the slurry.
  5. A positive electrode active material for a lithium ion secondary battery composed of a lithium nickel composite oxide having a hexagonal crystal layered structure, which is composed of secondary particles to which plural primary particles are aggregated, wherein the lithium nickel composite oxide comprises lithium, nickel, cobalt, manganese, and an element M with an atomic ratio of Li: Ni: Co: Mn: M = 1+u: 1-x1-y1-z1: x1: y1 : z1, wherein -0.05 ≤u≤ 0.50, M is at least one element selected from a group consisting of a transition metal element other than Ni, Co, Mn, a II group element, and a XIII group element, 0.15 ≦ x1 ≦ 0.25, 0.15≤yl ≦ 0.25, 0≦z1≤ 0.1, the lithium nickel composite oxide is having a cobalt rich layer or a manganese rich layer from a surface of a particle of the secondary particles toward an inside of the particle of the secondary particles and a layered void layer between the cobalt rich layer or the manganese rich layer and a center of the particle of the secondary particles, the cobalt rich layer comprises lithium, nickel, cobalt, manganese, and an element M with an atomic ratio of Li: Ni: Co: Mn: M = 1+u: 1-x2-y2-z2: x2: y2: z2, wherein -0.05 ≦ u ≦ 0.50, M is at least one element selected from a group consisting of a transition metal element other than Ni, Co, Mn, a II group element, and a XIII group element, x2, y2 and z2 satisfy x2=1, y2=0 and z2=0, or x2/((1-x2-y2-z2)+y2) ≧ 1, and z2 is within a range of 0 ≦ z2 ≦ 0.1, the manganese rich layer comprises lithium, nickel, cobalt, manganese, and an element M with an atomic ratio of Li: Ni: Co: Mn: M = 1+u: 1-x2-y2-z2: x2: y2: z2, wherein -0.05 ≦ u ≦ 0.50, M is at least one element selected from a group consisting of a transition metal element other than Ni, Co, Mn, a II group element, and a XIII group element, x2, y2 and z2 satisfy x2=0, y2=1 and z2=0, or y2/((1-x2-y2-z2)+x2) ≧ 1, and z2 is within a range of 0≦z2≦0.1, a thickness of the cobalt rich layer or the manganese rich layer is 1 % or more and 10% or less with respect to a diameter of the secondary particles, and also, a thickness of the void layer is 1% or more and 10% or less with respect to the diameter of the secondary particles, and a crystallite diameter calculated from a peak of (003) face by an X-ray diffraction measurement is 100 nm or more and 150 nm or less.
  6. The positive electrode active material for a lithium ion secondary battery according to claim 5, wherein, in a particle size distribution measured by a laser diffraction scattering method, a volume average particle size (Mv) is 4 micrometers or more and 10 micrometers or less, and [(D90-D10)/Mv] indicating a particle size distribution width, which is calculated by a cumulative 90 volume% particle size (D90) and a cumulative 10 volume% particle size (D10), and the volume average particle size (Mv), is 0.60 or less.
  7. A method for producing a positive electrode active material for a lithium ion secondary battery composed of a lithium nickel composite oxide having a hexagonal crystal layered structure, which is composed of secondary particles to which plural primary particles are aggregated, comprising: a lithium mixing process for forming a lithium mixture by mixing a nickel composite hydroxide and a lithium compound; and a firing process for firing the lithium mixture in an oxidizing atmosphere at a temperature of 800°C or more and 950°C or less, wherein the nickel composite hydroxide comprises nickel, cobalt, manganese, and an element M with an atomic ratio of Ni: Co: Mn: M = 1-x1-yl-z1: x1: y1; zl, wherein M is at least one element selected from a group consisting of a transition metal element other than Ni, Co, Mn, a II group element, and a XIII group element, 0.15≦x1≦0.25, 0.15≦y1≦0.25, 0≦z1≦0.1, the nickel composite hydroxide is having a cobalt rich layer or a manganese rich layer from a surface of a particle of the secondary particles toward an inside of the particle of the secondary particles and a layered low-density layer between the cobalt rich layer or the manganese rich layer and a center of the particle of the secondary particles, the cobalt rich layer comprises a nickel, a cobalt, a manganese, and an element M with an atomic ratio of Ni: Co: Mn: M = 1-x2-y2-z2: x2: y2: z2, wherein M is at least one element selected from a group consisting of a transition metal element other than Ni, Co, Mn, a II group element, and a XIII group element, x2, y2 and z2 satisfy x2=1, y2=0 and z2=0, or x2/((1-x2-y2-z2)+y2)≧1, and z2 is within a range of 0≦z2≦0.1, the manganese rich layer comprises a nickel, a cobalt, a manganese, and an element M with an atomic ratio of Ni: Co: Mn: M = 1-x2-y2-z2: x2: y2: z2, wherein M is at least one element selected from a group consisting of a transition metal element other than Ni, Co, Mn, a II group element, and a XIII group element, x2, y2 and z2 satisfy x2=0, y2=1 and z2=0, or y2/((1-x2-y2-z2)+x2)≧1, and z2 is within a range of 0 ≦z2≦0.1, and a thickness of the cobalt rich layer or the manganese rich layer is 1% or more and 10% or less with respect to a diameter of the secondary particles, and also, a thickness of the low-density layer is 1% or more and 10% or less with respect to the diameter of the secondary particles.
  8. A lithium ion secondary battery comprising a positive electrode at least including the positive electrode active material for the lithium ion secondary battery according to claim 5 or 6.

Description

Background of the Invention Field of the Invention The present invention relates to a nickel composite hydroxide, which is a precursor of a positive electrode active material for a lithium ion secondary battery, and a production method thereof, a positive electrode active material for a lithium ion secondary battery, which is having the nickel composite hydroxide as a raw material, and a production method thereof, and a lithium ion secondary battery using the positive electrode active material for the lithium ion secondary battery as a positive electrode material. This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2019-086217 filed on April 26, 2019, and Japanese Patent Application No. 2019-086218 filed on April 26, 2019. Description of Related Art In recent years, there is a strong demand for a development of compact and lightweight secondary batteries having a high energy density, due to the widespread use of portable electronic devices such as smart phones and notebook computers. For a positive electrode material of a lithium ion secondary battery, a lithium composite oxide is used as a positive electrode active material. A lithium cobalt composite oxide is relatively easy to synthesize, and also, in a lithium ion secondary battery using a lithium cobalt composite oxide as a positive electrode material, a 4 V-class high voltage can be obtained, so it is expected as a material for putting the secondary battery having high energy density into practical use. With respect to a lithium cobalt composite oxide, research and development have been promoted for achieving excellent initial capacity property and cycle characteristic in the secondary battery, and various results have been obtained already. However, a lithium cobalt composite oxide uses a rare and expensive cobalt compound as a raw material, so it is being a cause for an increase in cost of a positive electrode material and a secondary battery. A lithium ion secondary battery using a lithium cobalt composite oxide is having a unit cost per capacity four times higher than which of a nickel hydrogen battery, so its applicable use is limited extremely. Therefore, from a point of view of achieving further weight reduction and miniaturization of mobile devices, it is necessary to be able to produce a lithium ion secondary battery at a lower cost, by reducing a cost of a positive electrode active material. As a positive electrode active material, which can replace a lithium cobalt composite oxide, for example, a lithium nickel composite oxide (LiNiO2), a lithium nickel cobalt manganese composite oxide (LiNi1/3Co1/3Mn1/3O2) or the like can be cited. A lithium nickel composite oxide is expected as a positive electrode active material enabling a high capacity of a secondary battery, as a problem by an oxidization of an electrolyte solution is hardly caused, because a lithium nickel composite oxide shows an electric potential lower than a lithium cobalt composite oxide, and also, a lithium nickel composite oxide shows a high electric voltage similar to a lithium cobalt composite oxide. For example, in Patent Literature 1, nuclei having an empirical formula: LixM'zNi1-yM"yO2, and a composition having a coating with a cobalt/nickel ratio higher than the nuclei, are proposed, and indicated that they are excellent in a safety and a cycle efficiency. Also, in Patent Literature 2, it is proposed to inhibit a gelation at the time of a production of an electrode by reducing an alkalinity of an active material by having a manganese rich layer at an outer shell. Also, in Patent Literature 2 and Patent Literature 3, nickel manganese composite hydroxide particles and nickel cobalt manganese composite hydroxide particles, which are a precursor of a positive electrode active material for a non-aqueous electrolyte secondary battery, are proposed, and a high output and a high capacity are realized. Patent Literature 1: JP 2004-533104 APatent Literature 2: JP 2012-256435 APatent Literature 3: JP 2011-116580 A Summary of the Invention However, in Patent Literature 1, there is no description about a positive electrode resistance, and also, there is no description about a composition gradient. In Patent Literature 2, a gap is not introduced between a center layer and a manganese rich layer of an outer shell, so a diffusion of elements at the time of firing cannot be inhibited sufficiently, and more improvement of a cycle characteristic is required. Further, it is required that a positive electrode resistance is low as a positive electrode of a secondary battery, and an improvement of an output characteristic is required in a level higher than a conventional positive electrode, or an improvement of a cycle characteristic is required in a level higher than a conventional positive electrode, as a positive electrode of a secondary battery. Here, considering the above problems, a purpose of the present invention is to provide a nickel