WO2018043436A1 - Dissimilar metal-containing lithium-nickel composite oxide and production method therefor - Google Patents

Dissimilar metal-containing lithium-nickel composite oxide and production method therefor Download PDF

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WO2018043436A1
WO2018043436A1 PCT/JP2017/030810 JP2017030810W WO2018043436A1 WO 2018043436 A1 WO2018043436 A1 WO 2018043436A1 JP 2017030810 W JP2017030810 W JP 2017030810W WO 2018043436 A1 WO2018043436 A1 WO 2018043436A1
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lithium
composite oxide
positive electrode
nickel
nickel composite
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PCT/JP2017/030810
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French (fr)
Japanese (ja)
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田渕　光春
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国立研究開発法人産業技術総合研究所
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Publication of WO2018043436A1 publication Critical patent/WO2018043436A1/en

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    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G53/00—Compounds of nickel
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to a dissimilar metal-containing lithium nickel composite oxide and a method for producing the same.
  • the lithium-containing composite oxide is used as a positive electrode active material for lithium ion secondary batteries.
  • Lithium ion secondary batteries are not only used for power supplies for mobile phones and laptop computers, but are also expected to be used for medium and large power supplies such as in-vehicle and power load leveling systems. Has been made.
  • lithium nickelate is expected as a 4V class positive electrode material having a high specific capacity (200 mAh / g).
  • a high voltage upper limit voltage: 4.3 V
  • the cycle characteristics are remarkably deteriorated.
  • the present invention has been made in view of the current state of the prior art described above, and has an object to provide a lithium-containing composite oxide having high initial charge / discharge efficiency and in which deterioration of cycle characteristics is remarkably suppressed. To do.
  • the present inventors have surprisingly found that a lithium nickel-based composite oxide having a specific composition has high initial charge / discharge efficiency and cycle characteristics. It has been found that deterioration is remarkably suppressed.
  • the inventors of the present invention have completed the present invention by repeating further research based on such knowledge.
  • Item 1 General formula (1): Li x (Ni 1-y M y ) O 2 + ⁇ (1) [Wherein M represents at least one selected from the group consisting of Ge, Sn, Al, Co and Mn. x, y, and ⁇ represent 0.8 ⁇ x ⁇ 1.4, 0 ⁇ y ⁇ 0.500, and ⁇ 0.20 ⁇ ⁇ ⁇ 0.20, respectively. ] Lithium nickel composite oxide represented by Item 2. Item 2. The lithium nickel composite oxide according to Item 1, wherein M is Ge, Sn, Al, or Mn, or a combination of Al and Co. Item 3. Item 3.
  • the lithium nickel-based composite oxide according to Item 1 or 2 comprising a crystal phase of a hexagonal layered rock salt type structure or a crystal phase of a monoclinic layered rock salt type structure.
  • Item 4. The lithium nickel composite oxide according to Item 3, comprising only a crystal phase of a hexagonal layered rock salt type structure or a crystal phase of a monoclinic layered rock salt type structure.
  • Item 5. The method for producing a lithium nickel composite oxide according to any one of Items 1 to 4, A first step in which a lithium compound, a metal M compound, nickel hydroxide and / or a water-soluble nickel salt are mixed in an aqueous solvent, and the mixture obtained in the first step is fired in an oxidizing atmosphere. A manufacturing method including a 2nd process.
  • Item 6. The method according to Item 5, wherein the first step is a step of adding a metal M compound and nickel hydroxide and / or a water-soluble nickel salt to an aqueous solution containing a lithium compound.
  • Item 7. A positive electrode material for a lithium ion secondary battery, comprising the lithium nickel composite oxide according to any one of Items 1 to 4.
  • Item 8. The lithium ion secondary battery containing the positive electrode material for lithium ion secondary batteries of the said claim
  • the lithium nickel composite oxide of the present invention as a positive electrode active material for a lithium ion secondary battery, it is possible to provide a lithium ion secondary battery having high initial charge / discharge efficiency and exhibiting high cycle characteristics. It becomes possible.
  • FIG. 2 is a diagram showing an X-ray diffraction pattern of a sample obtained in Example 1.
  • FIG. It is a figure which shows the result of the charging / discharging test of the sample obtained in Example 1.
  • FIG. 6 is a diagram showing an X-ray diffraction pattern of a sample obtained in Example 2.
  • FIG. It is a figure which shows the result of the charging / discharging test of the sample obtained in Example 2.
  • FIG. 4 is a diagram showing an X-ray diffraction pattern of a sample obtained in Example 3.
  • FIG. It is a figure which shows the result of the charging / discharging test of the sample obtained in Example 3.
  • FIG. 1 It is a figure which shows the result of the charging / discharging test of the sample obtained by the comparative example 1. It is a figure which shows the X-ray-diffraction pattern of the sample obtained in Example 4. It is a figure which shows the result of the charging / discharging test of the sample obtained in Example 4. 6 is a diagram showing an X-ray diffraction pattern of a sample obtained in Example 5.
  • FIG. In the figure, the upper right part shows an enlarged view of the diffraction angle 2 ⁇ around 17 to 32 °. It is a figure which shows the result of the charging / discharging test of the sample obtained in Example 5.
  • Lithium nickel composite oxide The present invention includes lithium nickel composite oxide.
  • the lithium nickel composite oxide of the present invention has the general formula (1): Li x (Ni 1-y M y ) O 2 + ⁇ (1) [Wherein M represents at least one selected from the group consisting of Ge, Sn, Al, Co, and Mn. x, y, and ⁇ represent 0.8 ⁇ x ⁇ 1.4, 0 ⁇ y ⁇ 0.500, and ⁇ 0.20 ⁇ ⁇ ⁇ 0.20, respectively. ] It is a compound represented by these.
  • M represents at least one selected from the group consisting of Ge, Sn, Al, Co, and Mn.
  • M may be a single species or a combination of two or more species.
  • the two combinations include Ge and Sn, Ge and Al, Sn and Al, Ge and Co, Ge and Mn, Sn and Co, Sn and Mn, Al and Co, Al and Mn, and Co and Mn.
  • Examples of the three combinations include Ge, Sn, and Al, and a combination of Al, Co, and Mn.
  • the ratio is not particularly limited and can be determined as appropriate.
  • M is preferably Ge, Sn, Al, or Mn, or a combination of Al and Co, more preferably Ge, Sn, or Al, and particularly preferably Ge or Al. preferable.
  • x corresponds to the molar ratio of Li, Ni, and M (Li / (Ni + M)).
  • x is less than 0.8, the capacity is reduced, and when x exceeds 1.4, the crystal structure changes to a monoclinic LiNiO 2 —Li 2 NiO 3 based solid solution having poor battery characteristics.
  • 0.8 ⁇ x ⁇ 1.4 is preferable, and 0.9 ⁇ x ⁇ 1.3 is more preferable.
  • y is 0.0 ⁇ y ⁇ 0.500, preferably 0.001 ⁇ y ⁇ 0.300, more preferably 0.001 ⁇ y ⁇ 0.200.
  • ⁇ corresponds to the non-stoichiometry of the oxygen amount.
  • ⁇ is ⁇ 0.20 ⁇ ⁇ ⁇ 0.20, preferably ⁇ 0.15 ⁇ ⁇ ⁇ 0.15, more preferably ⁇ 0.10 ⁇ ⁇ ⁇ 0.10.
  • Examples of the lithium nickel composite oxide represented by the general formula (1) include Li 1.1 (Ni 0.9 Ge 0.1 ) O 2 , Li 1.02 (Ni 0.9973 Ge 0. 0027) O 2, Li 1.1 ( Ni 0.9 Sn 0.1) O 2, Li 1.14 (Ni 0.989 Sn 0.011) O 2, Li 1.1 (Ni 0.9 Al 0 .1 ) O 2 , Li 1.00 (Ni 0.919 Al 0.081 ) O 2 , Li 1.00 (Ni 0.8 Co 0.15 Al 0.05 ) O 2 , and Li 1.00 ( Ni 0.7 Mn 0.3 ) O 2 and the like.
  • the lithium nickel composite oxide of the present invention has a space group:
  • the lithium nickel-based composite oxide of the present invention may contain the crystal phase of the above hexagonal layered rock salt structure or the crystal phase of the monoclinic layered rock salt structure. , Cubic rock salt structure, etc.).
  • the ratio of the crystal phase of the hexagonal layered rock salt structure or the crystal phase of the monoclinic layered rock salt structure is based on the entire mixed phase from the viewpoint of initial charge / discharge efficiency and cycle characteristics (100 weight %) Is preferably 50 to 90% by weight.
  • the lithium nickel composite oxide of the present invention may be composed of only the crystal phase of the above hexagonal layered rock salt structure or the crystal phase of the monoclinic layered rock salt structure.
  • lithium nickel composite oxide represented by the general formula (1) when M is Ge, Sn, or Al, or a combination of Al and Co, a hexagonal layered rock salt structure It is easy to obtain a lithium nickel composite oxide containing a crystalline phase, and when M is Mn, a lithium nickel composite oxide containing a monoclinic layered rock salt structure crystalline phase is likely to be obtained.
  • the lithium nickel composite oxide of the present invention is based on the total amount of elements present in the Ni layer (3b site) as a reference (100%) and the amount of Ni in the Ni layer and the M
  • the occupation ratio of the sum of the amounts is preferably 99.90% or less, particularly preferably 70.00 to 99.80%.
  • the lattice constant a is preferably 2.8702 or less, and is 2.850 ⁇ or more and 2.865 ⁇ or less. Is more preferable.
  • the lattice constant a is preferably 5.000 ⁇ or less, and is 4.900 ⁇ or more and 4.980 ⁇ or less, and the lattice constant b is 8.600 ⁇ . It is preferable that it is below, and it is more preferable that it is 8.570 to 8.590.
  • the positive electrode active material that is particularly excellent in cycle characteristics when the crystal constant of the hexagonal layered rock salt type structure is within the above range and the lattice constant a and b of the crystal phase of the monoclinic layered rock salt type structure are within the above ranges. It can be.
  • the lattice constant c is preferably 14.10 to 14.20.
  • the lattice constant c is preferably 4.90 to 5.10.
  • the lattice constant c is in this range, a positive electrode active material having particularly excellent initial charge / discharge efficiency and cycle characteristics can be obtained.
  • the lithium nickel composite oxide of the present invention includes a crystal phase of a hexagonal layered rock salt structure
  • the value (c / a) obtained by dividing the lattice constant c by the lattice constant a is 4.940 or more and 4.960 or less. It is preferable that When the value (c / a) obtained by dividing the lattice constant c by the lattice constant a is in this range, a positive electrode active material having particularly excellent initial charge / discharge efficiency and cycle characteristics can be obtained.
  • the angle ⁇ between the a axis and the c axis is preferably 105.0 ° or more and 112.0 ° or less.
  • the angle ⁇ between the a-axis and the c-axis is in this range, a positive electrode active material that is particularly excellent in initial charge / discharge efficiency and cycle characteristics can be obtained.
  • Lithium-nickel-based composite oxide of the present invention when containing a crystal phase of a hexagonal layered rock-salt structure, it is preferable that the lattice volume is 101.00A 3 or less, 99.00A 3 or more 100.90A 3 below Preferably there is. On the other hand, if it contains a crystal phase of monoclinic layered rock-salt structure, it is preferable lattice volume is 200.00A 3 or more 202.00A 3 or less. When the lattice volume is in the range, a positive electrode active material that is particularly excellent in initial charge / discharge efficiency and cycle characteristics can be obtained.
  • the crystal structure, the occupation ratio of the sum of Ni and M in the Ni layer, the lattice constants a and c, and the lattice volume all use CuK ⁇ as the radiation source, and the measurement range of the diffraction angle 2 ⁇ is 10 °. It is determined or calculated by performing powder X-ray diffraction measurement at a temperature of 125 ° or less, defining a crystal structure as a hexagonal layered rock salt structure based on the measurement result, and performing Rietveld analysis.
  • the present invention further includes a method for producing the lithium nickel composite oxide described above.
  • the method for producing a lithium nickel composite oxide of the present invention comprises a step of mixing a lithium compound, a metal M compound, nickel hydroxide and / or a water-soluble nickel salt in an aqueous solvent (in this specification, “No. 1 step ”), and a step of firing the mixture in an oxidizing atmosphere (may be referred to as“ second step ”in this specification).
  • the lithium compound used in the first step is not particularly limited.
  • lithium hydroxide including hydrate
  • lithium carbonate including hydrate
  • lithium acetate including hydrate
  • lithium nitrate lithium perchlorate (water) (Including Japanese).
  • the lithium compound used in the first step is preferably excessive with respect to the number of moles of charged nickel and metal M, and more preferably 1.5 times or more and 2.5 times or less.
  • the metal M compound used in the first step is not particularly limited, and examples thereof include metal M oxides, hydroxides, chlorides, sulfates, nitrates, acetates, and hydrates thereof. Specific examples include germanium oxide, sodium stannate, aluminum hydroxide, cobalt nitrate (including hydrate), cobalt hydroxide, manganese chloride (including hydrate), manganese hydroxide, and the like.
  • nickel hydroxide can be used as the nickel hydroxide used in the first step. Moreover, you may use what is obtained by neutralizing water-soluble nickel salt with an alkali as needed. In this case, nickel hydroxide obtained by neutralizing a water-soluble nickel salt with an alkali in advance can be used in the first step, or the water-soluble nickel salt is charged into an aqueous solvent and alkali in the system. Nickel hydroxide can also be obtained by neutralizing with. Examples of the water-soluble nickel salt include nitrates, chlorides, sulfates, acetates, and hydrates thereof. Moreover, water-soluble nickel salt may be used individually by 1 type, and 2 or more types may be mixed and used for it.
  • the alkali used for neutralizing the water-soluble nickel salt is not particularly limited, and for example, sodium hydroxide, potassium hydroxide, lithium hydroxide, ammonia and the like can be used.
  • the concentration of the alkali may be a concentration that can maintain pH 11 or more during the neutralization step in which the water-soluble nickel salt is dropped into the alkali.
  • the temperature during the neutralization step is preferably -10 ° C or higher and 50 ° C or lower. By reducing the neutralization temperature, the nucleation rate of nickel hydroxide is increased, and finer and more reactive nickel hydroxide can be obtained.
  • an antifreeze solution such as ethanol may be added to the alkaline aqueous solution.
  • lithium hydroxide when making it react at low temperature, it is preferable to use lithium hydroxide as an alkali. This is because the temperature dependency of the solubility is flat as compared with sodium hydroxide or potassium hydroxide, so that alkali precipitation at low temperatures hardly occurs. In addition, it is not necessary to remove other alkali ions as lithium hydroxide impurities, and the remaining lithium hydroxide can be used as the above-described lithium compound. In order to add the water-soluble nickel salt to the alkaline solution during the neutralization step, it is preferable to gradually carry out over several hours in the dropping step in order to obtain uniform nickel hydroxide.
  • a metal M compound a compound containing a metal that is not an amphoteric metal (that is, when M is Co or manganese) is used, and nickel hydroxide is obtained by neutralizing a water-soluble nickel salt with an alkali. When obtained, a uniform mixed state can be easily obtained, and composition control becomes easy. Therefore, it is preferable to add a water-soluble salt of metal M as a metal M compound to a water-soluble nickel salt.
  • the water-soluble salt of the metal M include nitrates, chlorides, sulfates, acetates, and hydrates of the metal M.
  • the specific method of the first step is not particularly limited, but from the viewpoints of the availability of the lithium nickel composite oxide of the present invention and the ease of the production process, the metal M is added to the aqueous solution containing the lithium compound.
  • the step of adding the compound and nickel hydroxide and / or a water-soluble nickel salt is preferable.
  • the order in which the metal M compound and nickel hydroxide are added to the aqueous solution containing the lithium compound in the first step is not particularly limited, but the lithium nickel composite oxide of the present invention is easily obtained and the manufacturing process is easy. From this point of view, it is preferable to add nickel hydroxide after adding the metal M compound to the aqueous solution containing the lithium compound and confirming that the metal M compound is completely dissolved.
  • the aqueous solution containing the lithium compound used in the first step is preferably alkaline.
  • the alkali source is not particularly limited, and for example, sodium hydroxide, potassium hydroxide, lithium hydroxide, ammonia and the like can be used. It is preferable that an aqueous solution containing these alkali sources is first prepared, the metal M compound is added and dissolved, and then the lithium compound is added. Further, lithium hydroxide is preferable because it acts not only as an alkali source but also as a lithium compound.
  • the manufacturing method of the lithium nickel type complex oxide of the present invention includes a step of drying the mixture, if necessary, before the second step described later after the first step.
  • the drying method is not particularly limited and can be performed according to a conventional method. For example, a method of transferring the mixture obtained in the first step to a container such as a petri dish and putting it in a drier kept at 50 ° C. or more and drying for several hours can be mentioned.
  • the dry powder of the mixture obtained at the 1st process can be prepared.
  • the method for producing a lithium nickel composite oxide of the present invention includes a second step described later in an oxidizing atmosphere, if necessary, after the first step and before being subjected to a second step described later.
  • a step of firing at a temperature lower than the firing temperature (for example, 550 ° C. or lower) (hereinafter referred to as “pre-baking step”) may be included.
  • the oxidizing atmosphere is not particularly limited, and examples thereof include an atmospheric atmosphere and an oxygen stream.
  • the firing time is not particularly limited, and can be, for example, 5 hours or longer. Thus, since it can take in more lithium by performing preliminary
  • the mixture obtained in the first step is baked in an oxidizing atmosphere.
  • the oxidizing atmosphere is not particularly limited, and examples thereof include an atmospheric atmosphere and an oxygen stream.
  • the temperature is preferably 700 ° C. or less, and more preferably 600 ° C. or more and 700 ° C. or less.
  • the firing time is not particularly limited, and can be, for example, about 1 hour to 30 hours.
  • the fired product obtained in the above-described second step is optionally subjected to an oxidizing atmosphere in the same manner as in the above-described pre-firing step.
  • a step of baking at a temperature (for example, 550 ° C. or lower) lower than the baking temperature in the second step described above may be included.
  • the oxidizing atmosphere is not particularly limited, and examples thereof include an atmospheric atmosphere and an oxygen stream.
  • the firing time is not particularly limited, and can be, for example, 5 hours or longer. Thus, it is preferable to perform further baking after the above-described second step because more lithium can be taken in.
  • the method for producing a lithium nickel composite oxide of the present invention preferably includes a step of cooling the fired product obtained in the second step.
  • the method for cooling the fired product is not particularly limited, and can be performed according to a conventional method. For example, a method of leaving the fired product in a furnace to near room temperature can be used.
  • the obtained fired product is pulverized, washed, filtered, and dried. It is preferable to include at least one step.
  • the specific method of these steps is not particularly limited, and can be performed according to a conventional method.
  • Positive electrode material for lithium ion secondary battery and lithium ion secondary battery can be used as a positive electrode material for lithium ion secondary battery. Furthermore, by combining with the positive electrode material for lithium ion secondary battery, negative electrode, electrolyte (including solid electrolyte), and separator, the lithium ion secondary battery having high capacity and excellent cycle characteristics (non-aqueous lithium ion secondary battery) And an all-solid-state lithium ion secondary battery).
  • the negative electrode is not particularly limited, and examples thereof include metallic lithium, graphite, Si—SiO negative electrode, and LTO (Li 4 Ti 5 O 12 ) negative electrode.
  • the electrolyte is not particularly limited, and an organic electrolytic solution in which LiPF 6 or the like is used as an electrolyte salt and dissolved in various solvents such as ethyl carbonate (EC) or dimethyl carbonate (DMC), Li 2 S—P 2 S 5 , Li Examples thereof include inorganic sulfide solid electrolytes such as 2 S—GeS 2 —P 2 S 5 and Li 2 S—SiS 2 —Li 3 PO 4, and polymer polymers having lithium ion conductivity.
  • the separator is not particularly limited, and examples thereof include polyethylene and polypropylene.
  • Example 1 Sample Preparation 20.98 g (0.50 mol) of lithium hydroxide monohydrate was added to 200 ml of distilled water and completely dissolved. To the lithium hydroxide solution, 2.62 g (0.025 mol) of germanium oxide was added and completely dissolved, and then 20.86 g (0.225 mol) of nickel hydroxide was added and dispersed by stirring. The obtained mixture was transferred to a petri-tetrafluoroethylene petri dish, and the petri dish was placed in a drier kept at 100 ° C. and dried for 3 hours. The obtained dry powder was pulverized and mixed, heated to 650 ° C.
  • the obtained fired product was pulverized, washed with distilled water, filtered, and dried at 100 ° C. to obtain a product.
  • FIG. 1 shows an actual measurement (+) and a calculated (solid line) X-ray diffraction pattern of the product obtained above. Further, by Rietveld analysis, the obtained product is a hexagonal LiNiO 2 single phase having a layered rock salt structure, the lattice constant a is 2.86418 (4) ⁇ , and the lattice constant c is 14.19540 (17 ), Lattice volume is 100.851 (2) 3 3 , c / a value is 4.956, Ni and Ge ion occupancy in Ni layer is 92.07 (15)%, Ni and Ge in Li layer It was found that the ion occupancy was 0%.
  • the charge / discharge test was started at the start of charging, and was conducted up to 50 cycles under the conditions of potential range: 2.2 to 4.8 V, current density per positive electrode active material: 40 mA / g, test temperature: 30 ° C. The results are shown in FIG.
  • Example 2 the product obtained in Example 1 has an initial charge capacity of 239 mAh / g, an initial discharge capacity of 217 mAh / g, an initial charge / discharge efficiency of 90.7%, an initial discharge average voltage of 3.75 V, It was found that the initial discharge energy density was 815 mWh / g, the discharge capacity after 50 cycles was 184 mAh / g, and the discharge capacity retention rate after 50 cycles was 84.7%.
  • Example 2 Sample Preparation 20.98 g (0.50 mol) of lithium hydroxide monohydrate was added to 200 ml of distilled water and completely dissolved. To the lithium hydroxide solution, 6.67 g (0.025 mol) of sodium stannate was added and completely dissolved, and then 20.86 g (0.225 mol) of nickel hydroxide was added and dispersed by stirring. The obtained mixture was transferred to a petri-tetrafluoroethylene petri dish, and the petri dish was placed in a drier kept at 100 ° C. and dried for 3 hours. The obtained dry powder was pulverized and mixed, heated to 625 ° C.
  • the obtained fired product was pulverized, washed with distilled water, filtered, and dried at 100 ° C. to obtain a product.
  • FIG. 3 shows an actual measurement (+) and calculation (solid line) X-ray diffraction pattern of the product obtained above. Further, by Rietveld analysis, the obtained product is a hexagonal LiNiO 2 single phase having a layered rock salt structure, the lattice constant a is 2.86013 (10) 10, and the lattice constant c is 14.1509 (4 ), Lattice volume is 100.250 (6) ⁇ 3 , c / a value is 4.948, Ni and Sn ion occupancy in Ni layer is 81.12 (18)%, Ni and Sn in Li layer The ion occupancy was found to be 0.83 (6)%.
  • Example 4 the product obtained in Example 2 has an initial charge capacity of 236 mAh / g, an initial discharge capacity of 201 mAh / g, an initial charge / discharge efficiency of 84.8%, an initial discharge average voltage of 3.72 V, It was found that the initial discharge energy density was 746 mWh / g, the discharge capacity after 50 cycles was 171 mAh / g, and the discharge capacity retention rate after 50 cycles was 72.6%.
  • Example 3 Sample Preparation 20.98 g (0.50 mol) of lithium hydroxide monohydrate was added to 200 ml of distilled water and completely dissolved. After 1.95 g (0.025 mol) of aluminum hydroxide was added to the lithium hydroxide solution and completely dissolved, 20.86 g (0.225 mol) of nickel hydroxide was added and dispersed by stirring. The obtained mixture was transferred to a petri-tetrafluoroethylene petri dish, and the petri dish was placed in a drier kept at 100 ° C. and dried for 3 hours. The obtained dry powder was pulverized and mixed, heated to 650 ° C.
  • the obtained fired product was pulverized, washed with distilled water, filtered, and dried at 100 ° C. to obtain a product.
  • FIG. 5 shows an actual measurement (+) and calculation (solid line) X-ray diffraction pattern of the product obtained above. Further, by Rietveld analysis, the obtained product is a hexagonal LiNiO 2 single phase having a layered rock salt type structure, the lattice constant a is 2.86305 (5) ⁇ , and the lattice constant c is 14.1800 (2 ), Lattice volume is 100.62 (3) ⁇ 3 , c / a value is 4.953, Ni and Al ion occupancy in Ni layer is 99.78 (19)%, Ni and Al in Li layer The ion occupancy was found to be 0.09 (7)%.
  • Example 6 the product obtained in Example 3 has an initial charge capacity of 230 mAh / g, an initial discharge capacity of 207 mAh / g, an initial charge / discharge efficiency of 90.0%, an initial discharge average voltage of 3.70 V, It was found that the initial discharge energy density was 766 mWh / g, the discharge capacity after 50 cycles was 171 mAh / g, and the discharge capacity retention rate after 50 cycles was 82.6%.
  • the temperature is again raised to 750 ° C. in an oxygen stream over 1 hour in an electric furnace, fired for 20 hours, and then cooled to near room temperature in the furnace to obtain a fired product. It was.
  • the obtained fired product was pulverized, washed with distilled water, filtered, and dried at 100 ° C. to obtain a product.
  • FIG. 7 shows an actual measurement (+) and calculation (solid line) X-ray diffraction pattern of the product obtained above. Further, by Rietveld analysis, the obtained product is a hexagonal LiNiO 2 single phase having a layered rock salt structure, the lattice constant a is 2.87589 (3) ⁇ , and the lattice constant c is 14.19150 (13 ), Lattice volume is 100.6489 (18) 3 , c / a value is 4.935, Ni ion occupancy in Ni layer is 100%, Ni ion occupancy in Li layer is 0.56 (5 )%.
  • the product obtained in Comparative Example 1 has an initial charge capacity of 259 mAh / g, an initial discharge capacity of 220 mAh / g, an initial charge / discharge efficiency of 84.6%, an initial discharge average voltage of 3.80 V, Initial discharge energy density is 834 mWh / g, discharge capacity after 30 cycles is 176 mAh / g, discharge capacity maintenance rate after 30 cycles is 80.4%, discharge capacity after 50 cycles is 159 mAh / g, discharge after 50 cycles The capacity retention rate was found to be 72.6%.
  • Example 4 Sample Preparation Nickel (II) nitrate hexahydrate and cobalt (II) nitrate hexahydrate were weighed to a molar ratio of 80:15 (0.25 mol / batch), dissolved in 500 ml of distilled water, An aqueous metal salt solution was prepared. Next, 500 ml of distilled water was added to another container containing 50 g of sodium hydroxide and completely dissolved, and kept at 20 ° C. in a thermostatic bath. The aqueous metal salt solution prepared above was gradually added dropwise to the aqueous sodium hydroxide solution over about 3 hours to produce a coprecipitate. Thereafter, the coprecipitate was subjected to a bubbling treatment at room temperature for 2 days using an oxygen gas generator to ripen the precipitate. After aging, the precipitate was washed with water and filtered to obtain a raw material for firing.
  • Lithium hydroxide monohydrate 20.98 g (0.50 mol) was added to 200 ml of distilled water and completely dissolved. After 0.98 g (0.0125 mol) of aluminum hydroxide was added to the lithium hydroxide solution and completely dissolved, the firing raw material prepared above was added and dispersed by stirring with a mixer. The obtained mixture was transferred to a petri-tetrafluoroethylene petri dish, and the petri dish was placed in a drier kept at 50 ° C. and dried for 2 days. The obtained dry powder was pulverized and mixed, heated to 500 ° C. over 1 hour in an oxygen stream in an electric furnace, fired for 20 hours, and then cooled to near room temperature in the furnace to obtain a fired product. .
  • the temperature was again raised to 700 ° C. in an oxygen stream over 1 hour in an electric furnace, fired for 20 hours, and then cooled to near room temperature in the furnace to obtain a fired product. It was. After performing the water washing process using distilled water, it filtered, and the product was obtained by drying at 100 degreeC.
  • FIG. 9 shows an actual measurement (+) and calculation (solid line) X-ray diffraction pattern of the product obtained above. Further, the Rietveld analysis shows that the obtained product is a hexagonal LiNiO 2 single phase having a layered rock salt structure, the lattice constant a is 2.85522 (6) ⁇ , and the lattice constant c is 14.1473 (3 ), Lattice volume is 99.881 (4) ⁇ 3 , c / a value is 4.955, Ni, Al, and Co ion occupancy in Ni layer is 98.0 (3)%, in Li layer It was found that the occupation ratio of Ni, Al, and Co ions was 0%.
  • a positive electrode mixture was prepared using 0.5 mg of polytetrafluoroethylene, and the positive electrode mixture was pressure-bonded to an aluminum mesh to form a positive electrode It was.
  • a coin-type battery was fabricated using the positive electrode, metallic lithium as the negative electrode, 1M LiPF 6 / EC + DMC system as the electrolyte, and a separator, and a charge / discharge test was performed.
  • the charge / discharge test is the start of charging, with a potential range of 2.2 to 4.8 V (second and subsequent cycles: 2.2 to 4.6 V), current density per positive electrode active material: 40 mA / g, test temperature: 30 ° C. Up to 30 cycles were performed under the following conditions. The results are shown in FIG.
  • Example 10 the product obtained in Example 4 has an initial charge capacity of 209 mAh / g, an initial discharge capacity of 153 mAh / g, an initial charge / discharge efficiency of 73.2%, an initial discharge average voltage of 3.55 V, It was found that the initial discharge energy density was 566 mWh / g, the discharge capacity after 30 cycles was 126 mAh / g, and the discharge capacity retention rate after 30 cycles was 82.4%.
  • Example 5 Sample preparation Nickel (II) nitrate hexahydrate and manganese (II) chloride tetrahydrate were weighed to a molar ratio of 7: 3 (0.25 mol / batch), dissolved in 500 ml of distilled water, An aqueous metal salt solution was prepared. Next, 500 ml of distilled water was added to another container containing 50 g of sodium hydroxide and completely dissolved, and kept at 20 ° C. in a thermostatic bath. The aqueous metal salt solution prepared above was gradually added dropwise to the aqueous sodium hydroxide solution over about 3 hours to produce a coprecipitate. Thereafter, the coprecipitate was subjected to a bubbling treatment at room temperature for 2 days using an oxygen gas generator to ripen the precipitate. After aging, the precipitate was washed with water and filtered to obtain a raw material for firing.
  • Lithium hydroxide monohydrate 20.98 g (0.50 mol) was added to 200 ml of distilled water and completely dissolved.
  • the firing raw material prepared above was added to the lithium hydroxide solution and dispersed by stirring with a mixer.
  • the obtained mixture was transferred to a petri-tetrafluoroethylene petri dish, and the petri dish was placed in a drier kept at 50 ° C. and dried for 2 days.
  • the obtained dry powder was pulverized and mixed, heated to 500 ° C. over 1 hour in an oxygen stream in an electric furnace, fired for 20 hours, and then cooled to near room temperature in the furnace to obtain a fired product. . After the obtained fired product is pulverized, the temperature is again raised to 750 ° C.
  • FIG. 11 shows an actual measurement (+) and calculation (solid line) X-ray diffraction pattern of the product obtained above.
  • the diffraction angle 2 ⁇ is enlarged in the vicinity of 17 to 32 °.
  • Rietveld analysis revealed that the obtained product was a monoclinic Li 2 MnO 3 single phase having a layered rock salt structure.
  • the fact that the crystal phase of the product is monoclinic was confirmed by the presence of a small superlattice peak in the diffraction angle 2 ⁇ range of 20 to 30 ° as shown in the upper right part of FIG. .
  • the lattice constant a is 4.9425 (5) ⁇
  • the lattice constant b is 8.5575 (6) ⁇
  • the lattice constant c is 5.0099 (3) ⁇
  • ⁇ is 109.220 (9 ) °
  • lattice volume 200.5 (6) ⁇ 3 Ni and Mn ion occupancy in Ni layer 79.2 (4)%, Ni and Mn ion occupancy in Li layer 2.52 (7 )%.
  • Example 5 From FIG. 12, the product obtained in Example 5 has an initial charge capacity of 162 mAh / g, an initial discharge capacity of 125 mAh / g, an initial charge / discharge efficiency of 77.2%, an initial discharge average voltage of 3.73 V, It was found that the initial discharge energy density was 469 mWh / g, the discharge capacity after 50 cycles was 103 mAh / g, and the discharge capacity retention rate after 50 cycles was 82.0%.
  • Example 1 has almost the same initial charge / discharge capacity, initial discharge average voltage, and initial discharge energy density as compared with the sample of Comparative Example 1, and the initial charge / discharge efficiency, 50 cycles. It was found that the subsequent discharge capacity and the discharge capacity retention rate after 50 cycles were excellent.
  • Example 2 and 3 are sufficient as positive electrode materials for lithium ion secondary batteries although initial charge / discharge capacity, initial discharge average voltage, and initial discharge energy density are slightly inferior to those of Comparative Example 1. It was a usable level, the initial charge and discharge efficiency was almost the same, and it was found that the discharge capacity after 50 cycles and the discharge capacity maintenance rate after 50 cycles were excellent.
  • Example 4 Although the sample of Example 4 is inferior to the sample of Comparative Example 1 in initial charge / discharge capacity, initial charge / discharge efficiency, initial discharge average voltage, and initial discharge energy density, it is a positive electrode material for a lithium ion secondary battery. It was a usable level, and it was found that the discharge capacity retention rate after 30 cycles was excellent.
  • Example 5 is inferior to the sample of Comparative Example 1 in terms of initial charge / discharge capacity, initial charge / discharge efficiency, initial discharge average voltage, and initial discharge energy density, but as a positive electrode material for a lithium ion secondary battery. It was found that this was a usable level and the discharge capacity retention rate after 50 cycles was excellent.

Abstract

This lithium-nickel composite oxide represented by general formula (1): Lix(Ni1-yMy)O2+δ (1) [in the formula, M represents at least one selected from the group consisting of Ge, Sn, Al, Co, and Mn, and x, y, and δ represent 0.8≤x≤1.4, 0<y≤0.500, -0.20≤δ≤0.20, respectively] has a high capacitance and enables significant suppression of deterioration in cycle characteristics.

Description

異種金属含有リチウムニッケル複合酸化物及びその製造方法Dissimilar metal-containing lithium nickel composite oxide and method for producing the same
　本発明は、異種金属含有リチウムニッケル複合酸化物及びその製造方法に関する。 The present invention relates to a dissimilar metal-containing lithium nickel composite oxide and a method for producing the same.
　リチウム含有複合酸化物はリチウムイオン二次電池用の正極活物質として用いられている。リチウムイオン二次電池は、携帯電話、ノートパソコン用電源に使用されるだけでなく、車載用、電力負荷平準化システム用などの中型・大型電源用としても期待されており、一部実用化がなされている。 The lithium-containing composite oxide is used as a positive electrode active material for lithium ion secondary batteries. Lithium ion secondary batteries are not only used for power supplies for mobile phones and laptop computers, but are also expected to be used for medium and large power supplies such as in-vehicle and power load leveling systems. Has been made.
　リチウム含有複合酸化物の中でもニッケル酸リチウムは、高い比容量（２００ｍＡｈ／ｇ）を有する４Ｖ級正極材料として期待されている。しかしながら、ニッケル酸リチウムは、高容量を得るために高い電圧（上限電圧：４．３Ｖ）以上まで充電するとサイクル特性が著しく劣化することが知られている。 Among lithium-containing composite oxides, lithium nickelate is expected as a 4V class positive electrode material having a high specific capacity (200 mAh / g). However, it is known that when nickel nickelate is charged to a high voltage (upper limit voltage: 4.3 V) or higher in order to obtain a high capacity, the cycle characteristics are remarkably deteriorated.
　このような中、本発明者らは、特定の結晶構造を有し、かつ特定のパラメータを有するリチウム複合金属酸化物が、高容量を維持しつつ、サイクル特性の劣化を抑制することを見出している（下記特許文献１参照）。 Under such circumstances, the present inventors have found that a lithium composite metal oxide having a specific crystal structure and specific parameters suppresses deterioration of cycle characteristics while maintaining a high capacity. (See Patent Document 1 below).
　しかしながら、車載用および定置用などの長寿命が要求される用途においては、サイクル特性の劣化がさらに抑制された材料が必要である。 However, in applications that require a long life such as in-vehicle use or stationary use, a material in which deterioration of cycle characteristics is further suppressed is necessary.
特開２０１３－５６８０１号公報JP 2013-56801 A
　本発明は上記した従来技術の現状に鑑みてなされたものであり、高い初期充放電効率を有し、かつサイクル特性の劣化が顕著に抑制されたリチウム含有複合酸化物を提供することを目的とする。 The present invention has been made in view of the current state of the prior art described above, and has an object to provide a lithium-containing composite oxide having high initial charge / discharge efficiency and in which deterioration of cycle characteristics is remarkably suppressed. To do.
　本発明者らは上記した目的を達成すべく鋭意研究を重ねた結果、驚くべきことに、特定の組成を有するリチウムニッケル系複合酸化物が、高い初期充放電効率を有し、かつサイクル特性の劣化が顕著に抑制されることを見出した。本発明者らは、かかる知見に基づきさらなる研究を重ねることにより、本発明を完成させるに至った。 As a result of intensive studies to achieve the above object, the present inventors have surprisingly found that a lithium nickel-based composite oxide having a specific composition has high initial charge / discharge efficiency and cycle characteristics. It has been found that deterioration is remarkably suppressed. The inventors of the present invention have completed the present invention by repeating further research based on such knowledge.
　即ち、本発明は、以下の項に記載の発明を包含する。
項１．一般式（１）：
Ｌｉｘ（Ｎｉ１－ｙＭｙ）Ｏ２＋δ　　　　　（１）
［式中、ＭはＧｅ、Ｓｎ、Ａｌ、Ｃｏ及びＭｎからなる群から選択される少なくとも１種を示す。ｘ、ｙ及びδはそれぞれ、０．８≦ｘ≦１．４、０＜ｙ≦０．５００、－０．２０≦δ≦０．２０を示す。］
で表される、リチウムニッケル系複合酸化物。
項２．ＭがＧｅ、Ｓｎ、Ａｌ若しくはＭｎであるか、Ａｌ及びＣｏの組合せである、上記項１に記載のリチウムニッケル系複合酸化物。
項３．六方晶層状岩塩型構造の結晶相又は単斜晶層状岩塩型構造の結晶相を含む、上記項１又は２に記載のリチウムニッケル系複合酸化物。
項４．六方晶層状岩塩型構造の結晶相又は単斜晶層状岩塩型構造の結晶相のみからなる、上記項３に記載のリチウムニッケル系複合酸化物。
項５．上記項１～４のいずれかに記載のリチウムニッケル系複合酸化物の製造方法であって、
水性溶媒中で、リチウム化合物と、金属Ｍ化合物と、水酸化ニッケル及び／又は水溶性ニッケル塩とを混合する第１工程、及び
前記第１工程により得られた混合物を酸化性雰囲気下で焼成する第２工程
を含む、製造方法。
項６．前記第１工程が、リチウム化合物を含む水溶液に、金属Ｍ化合物と、水酸化ニッケル及び／又は水溶性ニッケル塩とを添加する工程である、上記項５に記載の製造方法。
項７．上記項１～４のいずれかに記載のリチウムニッケル系複合酸化物を含む、リチウムイオン二次電池用正極材料。
項８．上記項７に記載のリチウムイオン二次電池用正極材料を含む、リチウムイオン二次電池。 That is, the present invention includes the inventions described in the following sections.
Item 1. General formula (1):
Li x (Ni 1-y M y ) O 2 + δ (1)
[Wherein M represents at least one selected from the group consisting of Ge, Sn, Al, Co and Mn. x, y, and δ represent 0.8 ≦ x ≦ 1.4, 0 <y ≦ 0.500, and −0.20 ≦ δ ≦ 0.20, respectively. ]
Lithium nickel composite oxide represented by
Item 2. Item 2. The lithium nickel composite oxide according to Item 1, wherein M is Ge, Sn, Al, or Mn, or a combination of Al and Co.
Item 3. Item 3. The lithium nickel-based composite oxide according to Item 1 or 2, comprising a crystal phase of a hexagonal layered rock salt type structure or a crystal phase of a monoclinic layered rock salt type structure.
Item 4. Item 4. The lithium nickel composite oxide according to Item 3, comprising only a crystal phase of a hexagonal layered rock salt type structure or a crystal phase of a monoclinic layered rock salt type structure.
Item 5. The method for producing a lithium nickel composite oxide according to any one of Items 1 to 4,
A first step in which a lithium compound, a metal M compound, nickel hydroxide and / or a water-soluble nickel salt are mixed in an aqueous solvent, and the mixture obtained in the first step is fired in an oxidizing atmosphere. A manufacturing method including a 2nd process.
Item 6. Item 6. The method according to Item 5, wherein the first step is a step of adding a metal M compound and nickel hydroxide and / or a water-soluble nickel salt to an aqueous solution containing a lithium compound.
Item 7. A positive electrode material for a lithium ion secondary battery, comprising the lithium nickel composite oxide according to any one of Items 1 to 4.
Item 8. The lithium ion secondary battery containing the positive electrode material for lithium ion secondary batteries of the said claim | item 7.
　本発明のリチウムニッケル系複合酸化物をリチウムイオン二次電池用の正極活物質として用いることにより、高い初期充放電効率を有し、かつ高いサイクル特性を示すリチウムイオン二次電池を提供することが可能となる。 By using the lithium nickel composite oxide of the present invention as a positive electrode active material for a lithium ion secondary battery, it is possible to provide a lithium ion secondary battery having high initial charge / discharge efficiency and exhibiting high cycle characteristics. It becomes possible.
実施例１で得られた試料のＸ線回折パターンを示す図である。2 is a diagram showing an X-ray diffraction pattern of a sample obtained in Example 1. FIG. 実施例１で得られた試料の充放電試験の結果を示す図である。It is a figure which shows the result of the charging / discharging test of the sample obtained in Example 1. FIG. 実施例２で得られた試料のＸ線回折パターンを示す図である。6 is a diagram showing an X-ray diffraction pattern of a sample obtained in Example 2. FIG. 実施例２で得られた試料の充放電試験の結果を示す図である。It is a figure which shows the result of the charging / discharging test of the sample obtained in Example 2. FIG. 実施例３で得られた試料のＸ線回折パターンを示す図である。4 is a diagram showing an X-ray diffraction pattern of a sample obtained in Example 3. FIG. 実施例３で得られた試料の充放電試験の結果を示す図である。It is a figure which shows the result of the charging / discharging test of the sample obtained in Example 3. 比較例１で得られた試料のＸ線回折パターンを示す図である。It is a figure which shows the X-ray-diffraction pattern of the sample obtained by the comparative example 1. 比較例１で得られた試料の充放電試験の結果を示す図である。It is a figure which shows the result of the charging / discharging test of the sample obtained by the comparative example 1. 実施例４で得られた試料のＸ線回折パターンを示す図である。It is a figure which shows the X-ray-diffraction pattern of the sample obtained in Example 4. 実施例４で得られた試料の充放電試験の結果を示す図である。It is a figure which shows the result of the charging / discharging test of the sample obtained in Example 4. 実施例５で得られた試料のＸ線回折パターンを示す図である。なお、図中、右上部は回折角２θが１７～３２°付近を拡大した図を示す。6 is a diagram showing an X-ray diffraction pattern of a sample obtained in Example 5. FIG. In the figure, the upper right part shows an enlarged view of the diffraction angle 2θ around 17 to 32 °. 実施例５で得られた試料の充放電試験の結果を示す図である。It is a figure which shows the result of the charging / discharging test of the sample obtained in Example 5. FIG.
　以下、本発明について詳細に説明する。 Hereinafter, the present invention will be described in detail.
　１．リチウムニッケル系複合酸化物
　本発明は、リチウムニッケル系複合酸化物を包含する。本発明のリチウムニッケル系複合酸化物は、一般式（１）：
Ｌｉｘ（Ｎｉ１－ｙＭｙ）Ｏ２＋δ　　　　　（１）
［式中、ＭはＧｅ、Ｓｎ、Ａｌ、Ｃｏ、及びＭｎからなる群から選択される少なくとも１種を示す。ｘ、ｙ及びδはそれぞれ、０．８≦ｘ≦１．４、０＜ｙ≦０．５００、－０．２０≦δ≦０．２０を示す。］
で表される化合物である。 1. Lithium nickel composite oxide The present invention includes lithium nickel composite oxide. The lithium nickel composite oxide of the present invention has the general formula (1):
Li x (Ni 1-y M y ) O 2 + δ (1)
[Wherein M represents at least one selected from the group consisting of Ge, Sn, Al, Co, and Mn. x, y, and δ represent 0.8 ≦ x ≦ 1.4, 0 <y ≦ 0.500, and −0.20 ≦ δ ≦ 0.20, respectively. ]
It is a compound represented by these.
　上記一般式（１）において、ＭはＧｅ、Ｓｎ、Ａｌ、Ｃｏ、及びＭｎからなる群から選択される少なくとも１種を示す。Ｍは、１種単独であってもよいし、２種以上の組合せであってもよい。２種の組合せとしては、Ｇｅ及びＳｎ、Ｇｅ及びＡｌ、Ｓｎ及びＡｌ、Ｇｅ及びＣｏ、Ｇｅ及びＭｎ、Ｓｎ及びＣｏ、Ｓｎ及びＭｎ、Ａｌ及びＣｏ、Ａｌ及びＭｎ、並びにＣｏ及びＭｎの組合せが挙げられ、３種の組合せとしては、例えば、Ｇｅ、Ｓｎ及びＡｌ、並びにＡｌ、Ｃｏ及びＭｎの組合せが挙げられる。２種以上の組合せの場合、その比率は特に限定的ではなく、適宜決定することができる。また、中でも、Ｍは、Ｇｅ、Ｓｎ、Ａｌ若しくはＭｎであるか、Ａｌ及びＣｏの組合せであることが好ましく、Ｇｅ、Ｓｎ、又はＡｌであることがより好ましく、Ｇｅ又はＡｌであることが特に好ましい。 In the general formula (1), M represents at least one selected from the group consisting of Ge, Sn, Al, Co, and Mn. M may be a single species or a combination of two or more species. The two combinations include Ge and Sn, Ge and Al, Sn and Al, Ge and Co, Ge and Mn, Sn and Co, Sn and Mn, Al and Co, Al and Mn, and Co and Mn. Examples of the three combinations include Ge, Sn, and Al, and a combination of Al, Co, and Mn. In the case of a combination of two or more, the ratio is not particularly limited and can be determined as appropriate. Of these, M is preferably Ge, Sn, Al, or Mn, or a combination of Al and Co, more preferably Ge, Sn, or Al, and particularly preferably Ge or Al. preferable.
　上記一般式（１）において、ｘは、ＬｉとＮｉ及びＭとのモル比（Ｌｉ／（Ｎｉ＋Ｍ））に相当する。ｘが０．８未満であると容量の低下を招き、ｘが１．４を超えると結晶構造が電池特性の劣る単斜晶ＬｉＮｉＯ２－Ｌｉ２ＮｉＯ３系固溶体に変化することから、ｘは、０．８≦ｘ≦１．４である。また、サイクル特性の高い正極活物質とする観点からは、０．８≦ｘ≦１．３とすることが好ましく、０．９≦ｘ≦１．３とすることがより好ましい。 In the general formula (1), x corresponds to the molar ratio of Li, Ni, and M (Li / (Ni + M)). When x is less than 0.8, the capacity is reduced, and when x exceeds 1.4, the crystal structure changes to a monoclinic LiNiO 2 —Li 2 NiO 3 based solid solution having poor battery characteristics. 0.8 ≦ x ≦ 1.4. Further, from the viewpoint of a positive electrode active material having high cycle characteristics, 0.8 ≦ x ≦ 1.3 is preferable, and 0.9 ≦ x ≦ 1.3 is more preferable.
　上記一般式（１）において、ｙは、０．０＜ｙ≦０．５００であり、好ましくは０．００１≦ｙ≦０．３００、より好ましくは０．００１≦ｙ≦０．２００である。このような範囲とすることにより、初期充放電効率及びサイクル特性を向上させることができる。 In the general formula (1), y is 0.0 <y ≦ 0.500, preferably 0.001 ≦ y ≦ 0.300, more preferably 0.001 ≦ y ≦ 0.200. By setting it as such a range, initial stage charge / discharge efficiency and cycling characteristics can be improved.
　上記一般式（１）において、δは、酸素量の不定比性に相当する。δは、－０．２０≦δ≦０．２０、好ましくは－０．１５≦δ≦０．１５、より好ましくは－０．１０≦δ≦０．１０である。 In the above general formula (1), δ corresponds to the non-stoichiometry of the oxygen amount. δ is −0.20 ≦ δ ≦ 0.20, preferably −0.15 ≦ δ ≦ 0.15, more preferably −0.10 ≦ δ ≦ 0.10.
　上記一般式（１）で表されるリチウムニッケル系複合酸化物としては、例えば、Ｌｉ１．１（Ｎｉ０．９Ｇｅ０．１）Ｏ２、Ｌｉ１．０２（Ｎｉ０．９９７３Ｇｅ０．００２７）Ｏ２、Ｌｉ１．１（Ｎｉ０．９Ｓｎ０．１）Ｏ２、Ｌｉ１．１４（Ｎｉ０．９８９Ｓｎ０．０１１）Ｏ２、Ｌｉ１．１（Ｎｉ０．９Ａｌ０．１）Ｏ２、Ｌｉ１．００（Ｎｉ０．９１９Ａｌ０．０８１）Ｏ２、Ｌｉ１．００（Ｎｉ０．８Ｃｏ０．１５Ａｌ０．０５）Ｏ２、及びＬｉ１．００（Ｎｉ０．７Ｍｎ０．３）Ｏ２などが挙げられる。 Examples of the lithium nickel composite oxide represented by the general formula (1) include Li 1.1 (Ni 0.9 Ge 0.1 ) O 2 , Li 1.02 (Ni 0.9973 Ge 0. 0027) O 2, Li 1.1 ( Ni 0.9 Sn 0.1) O 2, Li 1.14 (Ni 0.989 Sn 0.011) O 2, Li 1.1 (Ni 0.9 Al 0 .1 ) O 2 , Li 1.00 (Ni 0.919 Al 0.081 ) O 2 , Li 1.00 (Ni 0.8 Co 0.15 Al 0.05 ) O 2 , and Li 1.00 ( Ni 0.7 Mn 0.3 ) O 2 and the like.
　本発明のリチウムニッケル系複合酸化物は、空間群： The lithium nickel composite oxide of the present invention has a space group:
Figure JPOXMLDOC01-appb-M000001
Figure JPOXMLDOC01-appb-M000001
に帰属する六方晶層状岩塩型構造の結晶相、又は空間群： Crystal phase of hexagonal layered rock salt structure belonging to, or space group:
Figure JPOXMLDOC01-appb-M000002
Figure JPOXMLDOC01-appb-M000002
に帰属する単斜晶層状岩塩型構造の結晶相を含むことが好ましい。本発明のリチウムニッケル系複合酸化物は、上記の六方晶層状岩塩型構造の結晶相又は単斜晶層状岩塩型構造の結晶相を含んでいればよく、他の岩塩型構造の結晶相（例えば、立方晶岩塩型構造等）を含む混合相であってもよい。混合相である場合、六方晶層状岩塩型構造の結晶相又は単斜晶層状岩塩型構造の結晶相の割合は、初期充放電効率及びサイクル特性の観点から、当該混合相全体を基準（１００重量％）として、５０～９０重量％が好ましい。また、本発明のリチウムニッケル系複合酸化物は、上記の六方晶層状岩塩型構造の結晶相又は単斜晶層状岩塩型構造の結晶相のみからなるものであってもよい。 It preferably includes a crystal phase of a monoclinic layered rock salt structure belonging to The lithium nickel-based composite oxide of the present invention may contain the crystal phase of the above hexagonal layered rock salt structure or the crystal phase of the monoclinic layered rock salt structure. , Cubic rock salt structure, etc.). In the case of a mixed phase, the ratio of the crystal phase of the hexagonal layered rock salt structure or the crystal phase of the monoclinic layered rock salt structure is based on the entire mixed phase from the viewpoint of initial charge / discharge efficiency and cycle characteristics (100 weight %) Is preferably 50 to 90% by weight. Further, the lithium nickel composite oxide of the present invention may be composed of only the crystal phase of the above hexagonal layered rock salt structure or the crystal phase of the monoclinic layered rock salt structure.
　例えば、上記一般式（１）で表されるリチウムニッケル系複合酸化物のうち、ＭがＧｅ、Ｓｎ、若しくはＡｌであるか、Ａｌ及びＣｏの組合せである場合には、六方晶層状岩塩型構造の結晶相を含むリチウムニッケル系複合酸化物が得られやすく、ＭがＭｎである場合には、単斜晶層状岩塩型構造の結晶相を含むリチウムニッケル系複合酸化物が得られやすい。 For example, in the lithium nickel composite oxide represented by the general formula (1), when M is Ge, Sn, or Al, or a combination of Al and Co, a hexagonal layered rock salt structure It is easy to obtain a lithium nickel composite oxide containing a crystalline phase, and when M is Mn, a lithium nickel composite oxide containing a monoclinic layered rock salt structure crystalline phase is likely to be obtained.
　本発明のリチウムニッケル系複合酸化物は、初期充放電効率及びサイクル特性の観点から、Ｎｉ層（３ｂサイト）に存在する元素の総量を基準（１００％）として、Ｎｉ層内におけるＮｉ量及びＭ量の和の占有率が９９．９０％以下、特に７０．００～９９．８０％であることが好ましい。 From the viewpoint of initial charge / discharge efficiency and cycle characteristics, the lithium nickel composite oxide of the present invention is based on the total amount of elements present in the Ni layer (3b site) as a reference (100%) and the amount of Ni in the Ni layer and the M The occupation ratio of the sum of the amounts is preferably 99.90% or less, particularly preferably 70.00 to 99.80%.
　本発明のリチウムニッケル系複合酸化物は、六方晶層状岩塩型構造の結晶相を含む場合は、格子定数ａが２．８７０Å以下であることが好ましく、２．８５０Å以上２．８６５Å以下であることがより好ましい。一方、単斜晶層状岩塩型構造の結晶相を含む場合は、格子定数ａが５．０００Å以下であることが好ましく、４．９００Å以上４．９８０Å以下であること、格子定数ｂが８．６００Å以下であることが好ましく、８．５７０Å以上８．５９０Å以下であることがより好ましい。六方晶層状岩塩型構造の結晶相については格子定数ａ、単斜晶層状岩塩型構造の結晶相については格子定数ａ及びｂが、当該範囲にあることにより、サイクル特性に特に優れた正極活物質とすることができる。 When the lithium nickel composite oxide of the present invention includes a crystal phase of a hexagonal layered rock salt structure, the lattice constant a is preferably 2.870２ or less, and is 2.850Å or more and 2.865Å or less. Is more preferable. On the other hand, when the crystal phase of the monoclinic layered rock salt structure is included, the lattice constant a is preferably 5.000Å or less, and is 4.900Å or more and 4.980Å or less, and the lattice constant b is 8.600Å. It is preferable that it is below, and it is more preferable that it is 8.570 to 8.590. The positive electrode active material that is particularly excellent in cycle characteristics when the crystal constant of the hexagonal layered rock salt type structure is within the above range and the lattice constant a and b of the crystal phase of the monoclinic layered rock salt type structure are within the above ranges. It can be.
　本発明のリチウムニッケル系複合酸化物は、六方晶層状岩塩型構造の結晶相を含む場合は、格子定数ｃが１４．１０Å以上１４．２０Å以下であることが好ましい。一方、単斜晶層状岩塩型構造の結晶相を含む場合は、格子定数ｃが４．９０Å以上５．１０Å以下であることが好ましい。格子定数ｃが当該範囲にあることにより、初期充放電効率及びサイクル特性に特に優れた正極活物質とすることができる。 When the lithium nickel-based composite oxide of the present invention contains a crystal phase having a hexagonal layered rock salt structure, the lattice constant c is preferably 14.10 to 14.20. On the other hand, when a crystal phase having a monoclinic layered rock salt structure is included, the lattice constant c is preferably 4.90 to 5.10. When the lattice constant c is in this range, a positive electrode active material having particularly excellent initial charge / discharge efficiency and cycle characteristics can be obtained.
　本発明のリチウムニッケル系複合酸化物は、六方晶層状岩塩型構造の結晶相を含む場合は、格子定数ｃを格子定数ａで除した値（ｃ／ａ）が４．９４０以上４．９６０以下であることが好ましい。格子定数ｃを格子定数ａで除した値（ｃ／ａ）が当該範囲にあることにより、初期充放電効率及びサイクル特性に特に優れた正極活物質とすることができる。 When the lithium nickel composite oxide of the present invention includes a crystal phase of a hexagonal layered rock salt structure, the value (c / a) obtained by dividing the lattice constant c by the lattice constant a is 4.940 or more and 4.960 or less. It is preferable that When the value (c / a) obtained by dividing the lattice constant c by the lattice constant a is in this range, a positive electrode active material having particularly excellent initial charge / discharge efficiency and cycle characteristics can be obtained.
　一方、単斜晶層状岩塩型構造の結晶相を含む場合は、ａ軸とｃ軸との間の角度βが１０５．０°以上１１２．０°以下であることが好ましい。ａ軸とｃ軸との間の角度βが当該範囲にあることにより、初期充放電効率及びサイクル特性に特に優れた正極活物質とすることができる。 On the other hand, when a crystal phase having a monoclinic layered rock salt structure is included, the angle β between the a axis and the c axis is preferably 105.0 ° or more and 112.0 ° or less. When the angle β between the a-axis and the c-axis is in this range, a positive electrode active material that is particularly excellent in initial charge / discharge efficiency and cycle characteristics can be obtained.
　本発明のリチウムニッケル系複合酸化物は、六方晶層状岩塩型構造の結晶相を含む場合は、格子体積が１０１．００Å３以下であることが好ましく、９９．００Å３以上１００．９０Å３以下であることが好ましい。一方、単斜晶層状岩塩型構造の結晶相を含む場合は、格子体積が２００．００Å３以上２０２．００Å３以下であることが好ましい。格子体積が当該範囲にあることにより、初期充放電効率及びサイクル特性に特に優れた正極活物質とすることができる。 Lithium-nickel-based composite oxide of the present invention, when containing a crystal phase of a hexagonal layered rock-salt structure, it is preferable that the lattice volume is 101.00A 3 or less, 99.00A 3 or more 100.90A 3 below Preferably there is. On the other hand, if it contains a crystal phase of monoclinic layered rock-salt structure, it is preferable lattice volume is 200.00A 3 or more 202.00A 3 or less. When the lattice volume is in the range, a positive electrode active material that is particularly excellent in initial charge / discharge efficiency and cycle characteristics can be obtained.
　なお、上記した結晶構造、Ｎｉ層内におけるＮｉ量及びＭ量の和の占有率、格子定数ａ及びｃ、並びに格子体積は、いずれもＣｕＫαを線源とし、回折角２θの測定範囲を１０°以上１２５°以下とする粉末Ｘ線回折測定を行い、当該測定結果を元に結晶構造を六方晶層状岩塩型構造として定義してリートベルト解析を行うことにより決定又は算出したものである。 The crystal structure, the occupation ratio of the sum of Ni and M in the Ni layer, the lattice constants a and c, and the lattice volume all use CuKα as the radiation source, and the measurement range of the diffraction angle 2θ is 10 °. It is determined or calculated by performing powder X-ray diffraction measurement at a temperature of 125 ° or less, defining a crystal structure as a hexagonal layered rock salt structure based on the measurement result, and performing Rietveld analysis.
　２．リチウムニッケル系複合酸化物の製造方法
　本発明は、さらに、上記したリチウムニッケル系複合酸化物の製造方法を包含する。本発明のリチウムニッケル系複合酸化物の製造方法は、水性溶媒中で、リチウム化合物と、金属Ｍ化合物と、水酸化ニッケル及び／又は水溶性ニッケル塩とを混合する工程（本明細書において「第１工程」と記載する場合がある。）、及び当該混合物を酸化性雰囲気下で焼成する工程（本明細書において「第２工程」と記載する場合がある。）を含む。 2. Method for Producing Lithium Nickel Composite Oxide The present invention further includes a method for producing the lithium nickel composite oxide described above. The method for producing a lithium nickel composite oxide of the present invention comprises a step of mixing a lithium compound, a metal M compound, nickel hydroxide and / or a water-soluble nickel salt in an aqueous solvent (in this specification, “No. 1 step ”), and a step of firing the mixture in an oxidizing atmosphere (may be referred to as“ second step ”in this specification).
　第１工程において用いるリチウム化合物としては特に限定的ではなく、例えば、水酸化リチウム（水和物を含む）、炭酸リチウム、酢酸リチウム（水和物を含む）、硝酸リチウム、過塩素酸リチウム（水和物を含む）などが挙げられる。また、第１工程において用いるリチウム化合物は、仕込みニッケル及び金属Ｍのモル数に対して過剰であることが好ましく、１．５倍以上２．５倍以下であることがより好ましい。 The lithium compound used in the first step is not particularly limited. For example, lithium hydroxide (including hydrate), lithium carbonate, lithium acetate (including hydrate), lithium nitrate, lithium perchlorate (water) (Including Japanese). Further, the lithium compound used in the first step is preferably excessive with respect to the number of moles of charged nickel and metal M, and more preferably 1.5 times or more and 2.5 times or less.
　第１工程において用いる金属Ｍ化合物としては特に限定的ではなく、例えば、金属Ｍの酸化物、水酸化物、塩化物、硫酸塩、硝酸塩、酢酸塩、及びこれらの水和物などが挙げられる。具体的には、酸化ゲルマニウム、スズ酸ナトリウム、水酸化アルミニウム、硝酸コバルト（水和物を含む）、水酸化コバルト、塩化マンガン（水和物を含む）、水酸化マンガンなどが挙げられる。 The metal M compound used in the first step is not particularly limited, and examples thereof include metal M oxides, hydroxides, chlorides, sulfates, nitrates, acetates, and hydrates thereof. Specific examples include germanium oxide, sodium stannate, aluminum hydroxide, cobalt nitrate (including hydrate), cobalt hydroxide, manganese chloride (including hydrate), manganese hydroxide, and the like.
　第１工程において用いる水酸化ニッケルとしては、市販のものを用いることができる。また、必要に応じて、水溶性ニッケル塩をアルカリで中和することにより得られるものを用いてもよい。この場合、あらかじめ水溶性ニッケル塩をアルカリで中和することにより得られた水酸化ニッケルを第１工程に使用することもできるし、水性溶媒中に水溶性ニッケル塩を投入して系中でアルカリで中和することで水酸化ニッケルを得ることもできる。水溶性ニッケル塩としては、例えば、硝酸塩、塩化物、硫酸塩、酢酸塩、及びその水和物などが挙げられる。また、水溶性ニッケル塩は１種単独で用いてもよいし、２種以上を混合して用いてもよい。 Commercially available nickel hydroxide can be used as the nickel hydroxide used in the first step. Moreover, you may use what is obtained by neutralizing water-soluble nickel salt with an alkali as needed. In this case, nickel hydroxide obtained by neutralizing a water-soluble nickel salt with an alkali in advance can be used in the first step, or the water-soluble nickel salt is charged into an aqueous solvent and alkali in the system. Nickel hydroxide can also be obtained by neutralizing with. Examples of the water-soluble nickel salt include nitrates, chlorides, sulfates, acetates, and hydrates thereof. Moreover, water-soluble nickel salt may be used individually by 1 type, and 2 or more types may be mixed and used for it.
　水溶性ニッケル塩を中和する際に用いるアルカリとしては特に限定的ではなく、例えば、水酸化ナトリウム、水酸化カリウム、水酸化リチウム、アンモニアなどを用いることができる。アルカリの濃度は、アルカリに対して水溶性ニッケル塩を滴下していく中和工程の間中、ｐＨ１１以上を維持できる濃度であればよい。また、中和工程時の温度は－１０℃以上５０℃以下とすることが好ましい。中和温度を低下させることにより水酸化ニッケルの核生成速度が速くなり、より微細な反応性の高い水酸化ニッケルを得ることができる。特に反応温度を０℃以下に保持するために、アルカリ水溶液にエタノールなどの不凍液を加えてもよい。このように、低温で反応させる場合、アルカリとしては水酸化リチウムを用いることが好ましい。これは、溶解度の温度依存性が水酸化ナトリウムや水酸化カリウムに比べてフラットであるため、低温でのアルカリ析出が起こりにくいためである。また、水酸化リチウム不純物として他のアルカリイオンを除去する必要がないうえに、残存する水酸化リチウムは上記したリチウム化合物として使用することもできるという工程上のメリットもある。中和工程時にアルカリ溶液に水溶性ニッケル塩を加えるには、均一な水酸化ニッケルを得るために滴下工程により数時間かけて徐々に行うことが好ましい。また、必要に応じて滴下終了後、沈殿を熟成するために沈殿を室温にて空気を吹き込みながら数時間以上撹拌してもよい。さらに、必要に応じて、沈殿を調製した後、残留アルカリを除去するために、沈殿を蒸留水で水洗後、濾過してもよい。 The alkali used for neutralizing the water-soluble nickel salt is not particularly limited, and for example, sodium hydroxide, potassium hydroxide, lithium hydroxide, ammonia and the like can be used. The concentration of the alkali may be a concentration that can maintain pH 11 or more during the neutralization step in which the water-soluble nickel salt is dropped into the alkali. The temperature during the neutralization step is preferably -10 ° C or higher and 50 ° C or lower. By reducing the neutralization temperature, the nucleation rate of nickel hydroxide is increased, and finer and more reactive nickel hydroxide can be obtained. In particular, in order to maintain the reaction temperature at 0 ° C. or lower, an antifreeze solution such as ethanol may be added to the alkaline aqueous solution. Thus, when making it react at low temperature, it is preferable to use lithium hydroxide as an alkali. This is because the temperature dependency of the solubility is flat as compared with sodium hydroxide or potassium hydroxide, so that alkali precipitation at low temperatures hardly occurs. In addition, it is not necessary to remove other alkali ions as lithium hydroxide impurities, and the remaining lithium hydroxide can be used as the above-described lithium compound. In order to add the water-soluble nickel salt to the alkaline solution during the neutralization step, it is preferable to gradually carry out over several hours in the dropping step in order to obtain uniform nickel hydroxide. Moreover, after completion | finish of dripping as needed, in order to mature | ripen a precipitation, you may stir a precipitation for several hours or more, blowing in air at room temperature. Further, if necessary, after preparing the precipitate, the precipitate may be washed with distilled water and then filtered in order to remove residual alkali.
　また、金属Ｍ化合物として、両性金属ではない金属を含む化合物（即ち、ＭがＣｏ又はマンガンである場合）を用いる場合であって、水溶性ニッケル塩をアルカリで中和することにより水酸化ニッケルを得る場合、容易に均一混合状態が得られ、組成制御が容易になるため、水溶性ニッケル塩に金属Ｍ化合物として金属Ｍの水溶性塩を添加することが好ましい。このような金属Ｍの水溶性塩としては、例えば、金属Ｍの硝酸塩、塩化物、硫酸塩、酢酸塩、及びこれらの水和物などが挙げられる。 Further, as a metal M compound, a compound containing a metal that is not an amphoteric metal (that is, when M is Co or manganese) is used, and nickel hydroxide is obtained by neutralizing a water-soluble nickel salt with an alkali. When obtained, a uniform mixed state can be easily obtained, and composition control becomes easy. Therefore, it is preferable to add a water-soluble salt of metal M as a metal M compound to a water-soluble nickel salt. Examples of the water-soluble salt of the metal M include nitrates, chlorides, sulfates, acetates, and hydrates of the metal M.
　このような第１工程の具体的な方法としては、特に制限されないが、本発明のリチウムニッケル系複合酸化物の得やすさと製造工程の容易さの観点から、リチウム化合物を含む水溶液に、金属Ｍ化合物と、水酸化ニッケル及び／又は水溶性ニッケル塩とを添加する工程とすることが好ましい。この場合、第１工程において、リチウム化合物を含む水溶液に金属Ｍ化合物及び水酸化ニッケルを添加する順序としては、特に制限されないが、本発明のリチウムニッケル系複合酸化物の得やすさと製造工程の容易さの観点から、リチウム化合物を含む水溶液に金属Ｍ化合物を添加し、金属Ｍ化合物が完全に溶解したことを確認した後に、水酸化ニッケルを添加することが好ましい。 The specific method of the first step is not particularly limited, but from the viewpoints of the availability of the lithium nickel composite oxide of the present invention and the ease of the production process, the metal M is added to the aqueous solution containing the lithium compound. The step of adding the compound and nickel hydroxide and / or a water-soluble nickel salt is preferable. In this case, the order in which the metal M compound and nickel hydroxide are added to the aqueous solution containing the lithium compound in the first step is not particularly limited, but the lithium nickel composite oxide of the present invention is easily obtained and the manufacturing process is easy. From this point of view, it is preferable to add nickel hydroxide after adding the metal M compound to the aqueous solution containing the lithium compound and confirming that the metal M compound is completely dissolved.
　また、第１工程において用いるリチウム化合物を含む水溶液は、アルカリ性であることが好ましい。アルカリ源としては特に限定的ではなく、例えば、水酸化ナトリウム、水酸化カリウム、水酸化リチウム、アンモニアなどを用いることができる。これらアルカリ源を含む水溶液をまず作製し、金属Ｍ化合物を添加して溶解した後、リチウム化合物を添加することが好ましい。また、水酸化リチウムは、アルカリ源としてだけではなく、リチウム化合物としても作用するため好ましい。 Further, the aqueous solution containing the lithium compound used in the first step is preferably alkaline. The alkali source is not particularly limited, and for example, sodium hydroxide, potassium hydroxide, lithium hydroxide, ammonia and the like can be used. It is preferable that an aqueous solution containing these alkali sources is first prepared, the metal M compound is added and dissolved, and then the lithium compound is added. Further, lithium hydroxide is preferable because it acts not only as an alkali source but also as a lithium compound.
　また、本発明のリチウムニッケル系複合酸化物の製造方法は、上記した第１工程の後、後述する第２工程に供する前に、必要に応じて、混合物を乾燥する工程を含むことが好ましい。乾燥方法としては特に限定的ではなく常法に従って行うことができる。例えば、第１工程で得られた混合物をシャーレ等の容器に移し、５０℃以上に保温した乾燥機に入れて数時間乾燥を行う方法などが挙げられる。当該乾燥工程により、第１工程で得られた混合物の乾燥粉末を調製することができる。また、乾燥後、第２工程に供する前に、必要に応じて得られた乾燥粉末を粉砕してもよい。 Moreover, it is preferable that the manufacturing method of the lithium nickel type complex oxide of the present invention includes a step of drying the mixture, if necessary, before the second step described later after the first step. The drying method is not particularly limited and can be performed according to a conventional method. For example, a method of transferring the mixture obtained in the first step to a container such as a petri dish and putting it in a drier kept at 50 ° C. or more and drying for several hours can be mentioned. By the said drying process, the dry powder of the mixture obtained at the 1st process can be prepared. Moreover, you may grind | pulverize the dry powder obtained as needed before using for a 2nd process after drying.
　また、本発明のリチウムニッケル系複合酸化物の製造方法は、上記した第１工程の後、後述する第２工程に供する前に、必要に応じて、酸化性雰囲気下で、後述する第２工程における焼成温度よりも低い温度（例えば、５５０℃以下）で焼成する工程（以下、「予備焼成工程」と記載する。）を含んでいてもよい。酸化性雰囲気としては特に限定的ではなく、例えば、大気中雰囲気、酸素気流中などが挙げられる。また、焼成時間としては特に限定的ではなく、例えば、５時間以上とすることができる。このように、後述する第２工程に供する前に、予備焼成を行うことにより、リチウムをより多く取り込むことができるため、好ましい。 In addition, the method for producing a lithium nickel composite oxide of the present invention includes a second step described later in an oxidizing atmosphere, if necessary, after the first step and before being subjected to a second step described later. A step of firing at a temperature lower than the firing temperature (for example, 550 ° C. or lower) (hereinafter referred to as “pre-baking step”) may be included. The oxidizing atmosphere is not particularly limited, and examples thereof include an atmospheric atmosphere and an oxygen stream. Further, the firing time is not particularly limited, and can be, for example, 5 hours or longer. Thus, since it can take in more lithium by performing preliminary | backup baking before using for the 2nd process mentioned later, it is preferable.
　第２工程では、第１工程で得られた混合物を酸化性雰囲気下で焼成する。酸化性雰囲気としては特に限定的ではなく、例えば、大気中雰囲気、酸素気流中などが挙げられる。焼成温度としては、７００℃を超えるとサイクル特性が劣化するおそれがあるため、７００℃以下の温度とすることが好ましく、６００℃以上７００℃以下とすることがより好ましい。また、焼成時間としては特に限定的ではなく、例えば、１時間～３０時間程度とすることができる。 In the second step, the mixture obtained in the first step is baked in an oxidizing atmosphere. The oxidizing atmosphere is not particularly limited, and examples thereof include an atmospheric atmosphere and an oxygen stream. As the firing temperature, if the temperature exceeds 700 ° C., the cycle characteristics may be deteriorated. Therefore, the temperature is preferably 700 ° C. or less, and more preferably 600 ° C. or more and 700 ° C. or less. Further, the firing time is not particularly limited, and can be, for example, about 1 hour to 30 hours.
　また、本発明のリチウムニッケル系複合酸化物の製造方法は、上記した第２工程により得られた焼成物を、必要に応じて、上記した予備焼成工程と同様にして、酸化性雰囲気下で、上記した第２工程における焼成温度よりも低い温度（例えば、５５０℃以下）で焼成する工程を含んでいてもよい。酸化性雰囲気としては特に限定的ではなく、例えば、大気中雰囲気、酸素気流中などが挙げられる。また、焼成時間としては特に限定的ではなく、例えば、５時間以上とすることができる。このように、上記した第２工程の後に、さらに焼成を行うことにより、リチウムをより多く取り込むことができるため、好ましい。 Further, in the method for producing a lithium nickel-based composite oxide of the present invention, the fired product obtained in the above-described second step is optionally subjected to an oxidizing atmosphere in the same manner as in the above-described pre-firing step. A step of baking at a temperature (for example, 550 ° C. or lower) lower than the baking temperature in the second step described above may be included. The oxidizing atmosphere is not particularly limited, and examples thereof include an atmospheric atmosphere and an oxygen stream. Further, the firing time is not particularly limited, and can be, for example, 5 hours or longer. Thus, it is preferable to perform further baking after the above-described second step because more lithium can be taken in.
　また、本発明のリチウムニッケル系複合酸化物の製造方法は、上記した第２工程により得られた焼成物を冷却する工程を含むことが好ましい。焼成物の冷却方法としては特に限定的ではなく常法に従って行うことができ、例えば、焼成後、炉内で室温付近まで放置する方法などが挙げられる。 Moreover, the method for producing a lithium nickel composite oxide of the present invention preferably includes a step of cooling the fired product obtained in the second step. The method for cooling the fired product is not particularly limited, and can be performed according to a conventional method. For example, a method of leaving the fired product in a furnace to near room temperature can be used.
　さらに、本発明のリチウムニッケル系複合酸化物の製造方法は、必要に応じて、上記した冷却工程を経た後、得られた焼成物を粉砕する工程、洗浄する工程、濾過する工程、及び乾燥する工程の少なくとも１つの工程を含むことが好ましい。これらの工程の具体的な方法としては特に限定的ではなく、常法に従って行うことができる。 Furthermore, in the method for producing a lithium nickel composite oxide of the present invention, if necessary, after the cooling step described above, the obtained fired product is pulverized, washed, filtered, and dried. It is preferable to include at least one step. The specific method of these steps is not particularly limited, and can be performed according to a conventional method.
　３．リチウムイオン二次電池用正極材料及びリチウムイオン二次電池
　上記した本発明のリチウムニッケル系複合酸化物は、リチウムイオン二次電池用正極材料として用いることができる。さらに、当該リチウムイオン二次電池用正極材料、負極、電解質（固体電解質を含む）、及びセパレータと組み合わせることにより、高容量かつサイクル特性に優れたリチウムイオン二次電池（非水系リチウムイオン二次電池及び全固体リチウムイオン二次電池）とすることができる。負極としては特に限定的ではなく、例えば、金属リチウム、黒鉛、Ｓｉ－ＳｉＯ系負極、ＬＴＯ（Ｌｉ４Ｔｉ５Ｏ１２）系負極などが挙げられる。電解質としては特に限定的ではなく、ＬｉＰＦ６等を電解質塩とし、炭酸エチル（ＥＣ）や炭酸ジメチル（ＤＭＣ）などの各種溶媒に溶解させた有機電解液、Ｌｉ２Ｓ－Ｐ２Ｓ５、Ｌｉ２Ｓ－ＧｅＳ２－Ｐ２Ｓ５、Ｌｉ２Ｓ－ＳｉＳ２－Ｌｉ３ＰＯ４などの無機硫化物系固体電解質、リチウムイオン導電性を有する高分子ポリマーなどが挙げられる。セパレータとしては特に限定的ではなく、ポリエチレン、ポリプロピレンなどが挙げられる。 3. Positive electrode material for lithium ion secondary battery and lithium ion secondary battery The above-described lithium nickel composite oxide of the present invention can be used as a positive electrode material for lithium ion secondary battery. Furthermore, by combining with the positive electrode material for lithium ion secondary battery, negative electrode, electrolyte (including solid electrolyte), and separator, the lithium ion secondary battery having high capacity and excellent cycle characteristics (non-aqueous lithium ion secondary battery) And an all-solid-state lithium ion secondary battery). The negative electrode is not particularly limited, and examples thereof include metallic lithium, graphite, Si—SiO negative electrode, and LTO (Li 4 Ti 5 O 12 ) negative electrode. The electrolyte is not particularly limited, and an organic electrolytic solution in which LiPF 6 or the like is used as an electrolyte salt and dissolved in various solvents such as ethyl carbonate (EC) or dimethyl carbonate (DMC), Li 2 S—P 2 S 5 , Li Examples thereof include inorganic sulfide solid electrolytes such as 2 S—GeS 2 —P 2 S 5 and Li 2 S—SiS 2 —Li 3 PO 4, and polymer polymers having lithium ion conductivity. The separator is not particularly limited, and examples thereof include polyethylene and polypropylene.
　以下、実施例を挙げて本発明をさらに詳細に説明するが、本発明は下記の例に限定されるものではない。 Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples.
　［実施例１］
　試料の調製
　水酸化リチウム１水和物２０．９８ｇ（０．５０ｍｏｌ）を２００ｍｌの蒸留水に加え完全に溶解させた。当該水酸化リチウム溶液に酸化ゲルマニウム２．６２ｇ（０．０２５ｍｏｌ）を加えて完全に溶解させた後、水酸化ニッケル２０．８６ｇ（０．２２５ｍｏｌ）を加えて撹拌して分散させた。得られた混合物をポリテトラフルオロエチレン製シャーレに移し、当該シャーレを１００℃に保たれた乾燥機に入れ、３時間かけて乾燥を行った。得られた乾燥粉末を粉砕混合し、電気炉にて酸素気流中１時間かけて６５０℃に昇温し、２０時間焼成を行い、その後、炉内で室温付近まで冷却して焼成物を得た。得られた焼成物を粉砕後、蒸留水を用いて水洗処理を行った後、濾過し、１００℃で乾燥することにより生成物を得た。 [Example 1]
Sample Preparation 20.98 g (0.50 mol) of lithium hydroxide monohydrate was added to 200 ml of distilled water and completely dissolved. To the lithium hydroxide solution, 2.62 g (0.025 mol) of germanium oxide was added and completely dissolved, and then 20.86 g (0.225 mol) of nickel hydroxide was added and dispersed by stirring. The obtained mixture was transferred to a petri-tetrafluoroethylene petri dish, and the petri dish was placed in a drier kept at 100 ° C. and dried for 3 hours. The obtained dry powder was pulverized and mixed, heated to 650 ° C. over 1 hour in an oxygen stream in an electric furnace, fired for 20 hours, and then cooled to near room temperature in the furnace to obtain a fired product. . The obtained fired product was pulverized, washed with distilled water, filtered, and dried at 100 ° C. to obtain a product.
　Ｘ線回折による評価
　上記で得られた生成物の実測（＋）及び計算（実線）Ｘ線回折パターンを図１に示す。また、リートベルト解析により、得られた生成物が層状岩塩型構造を有する六方晶ＬｉＮｉＯ２単相であること、格子定数ａが２．８６４１８（４）Å、格子定数ｃが１４．１９５４０（１７）Å、格子体積が１００．８５１（２）Å３、ｃ／ａ値が４．９５６、Ｎｉ層内のＮｉ及びＧｅイオン占有率が９２．０７（１５）％、Ｌｉ層内のＮｉ及びＧｅイオン占有率が０％であることが分かった。 Evaluation by X-ray diffraction FIG. 1 shows an actual measurement (+) and a calculated (solid line) X-ray diffraction pattern of the product obtained above. Further, by Rietveld analysis, the obtained product is a hexagonal LiNiO 2 single phase having a layered rock salt structure, the lattice constant a is 2.86418 (4) Å, and the lattice constant c is 14.19540 (17 ), Lattice volume is 100.851 (2) ３ 3 , c / a value is 4.956, Ni and Ge ion occupancy in Ni layer is 92.07 (15)%, Ni and Ge in Li layer It was found that the ion occupancy was 0%.
　化学分析
　ＩＣＰ発光分析により上記で得られた生成物の化学組成を求めたところ、Ｌｉ／（Ｎｉ＋Ｇｅ）比が１．０２、Ｇｅ／（Ｎｉ＋Ｇｅ）比が０．００２７であることが分かった。 Chemical analysis The chemical composition of the product obtained above was determined by ICP emission analysis, and it was found that the Li / (Ni + Ge) ratio was 1.02 and the Ge / (Ni + Ge) ratio was 0.0027.
　充放電特性評価
　上記で得られた生成物５ｍｇをアセチレンブラック５ｍｇと混合した後、ポリテトラフルオロエチレン０．５ｍｇを用いて正極合材を作製し、当該正極合材をアルミニウムメッシュに圧着して正極とした。次いで、当該正極、負極として金属リチウム、電解液として１Ｍ　ＬｉＰＦ６／ＥＣ＋ＤＭＣ系（ＥＣは炭酸エチレン、ＤＭＣは炭酸ジメチルを示す。）、及びセパレータを用いてコイン型電池を作製し、充放電試験を行った。充放電試験は充電開始で、電位範囲：２．２～４．８Ｖ、正極活物質あたりの電流密度：４０ｍＡ／ｇ、試験温度：３０℃の条件で５０サイクルまで行った。結果を図２に示す。 Evaluation of charge / discharge characteristics After 5 mg of the product obtained above was mixed with 5 mg of acetylene black, a positive electrode mixture was prepared using 0.5 mg of polytetrafluoroethylene, and the positive electrode mixture was pressure-bonded to an aluminum mesh to form a positive electrode It was. Subsequently, a coin-type battery was prepared using the positive electrode, metallic lithium as the negative electrode, and 1M LiPF 6 / EC + DMC system (EC represents ethylene carbonate, DMC represents dimethyl carbonate) as an electrolyte, and a separator, and a charge / discharge test was performed. went. The charge / discharge test was started at the start of charging, and was conducted up to 50 cycles under the conditions of potential range: 2.2 to 4.8 V, current density per positive electrode active material: 40 mA / g, test temperature: 30 ° C. The results are shown in FIG.
　図２より、実施例１で得られた生成物は、初期充電容量が２３９ｍＡｈ／ｇ、初期放電容量が２１７ｍＡｈ／ｇ、初期充放電効率が９０．７％、初期放電平均電圧が３．７５Ｖ、初期放電エネルギー密度が８１５ｍＷｈ／ｇ、５０サイクル後の放電容量が１８４ｍＡｈ／ｇ、５０サイクル後の放電容量維持率が８４．７％であることが分かった。 2, the product obtained in Example 1 has an initial charge capacity of 239 mAh / g, an initial discharge capacity of 217 mAh / g, an initial charge / discharge efficiency of 90.7%, an initial discharge average voltage of 3.75 V, It was found that the initial discharge energy density was 815 mWh / g, the discharge capacity after 50 cycles was 184 mAh / g, and the discharge capacity retention rate after 50 cycles was 84.7%.
　［実施例２］
　試料の調製
　水酸化リチウム１水和物２０．９８ｇ（０．５０ｍｏｌ）を２００ｍｌの蒸留水に加え完全に溶解させた。当該水酸化リチウム溶液にスズ酸ナトリウム６．６７ｇ（０．０２５ｍｏｌ）を加えて完全に溶解させた後、水酸化ニッケル２０．８６ｇ（０．２２５ｍｏｌ）を加えて撹拌して分散させた。得られた混合物をポリテトラフルオロエチレン製シャーレに移し、当該シャーレを１００℃に保たれた乾燥機に入れ、３時間かけて乾燥を行った。得られた乾燥粉末を粉砕混合し、電気炉にて酸素気流中１時間かけて６２５℃に昇温し、２０時間焼成を行い、その後、炉内で室温付近まで冷却して焼成物を得た。得られた焼成物を粉砕後、蒸留水を用いて水洗処理を行った後、濾過し、１００℃で乾燥することにより生成物を得た。 [Example 2]
Sample Preparation 20.98 g (0.50 mol) of lithium hydroxide monohydrate was added to 200 ml of distilled water and completely dissolved. To the lithium hydroxide solution, 6.67 g (0.025 mol) of sodium stannate was added and completely dissolved, and then 20.86 g (0.225 mol) of nickel hydroxide was added and dispersed by stirring. The obtained mixture was transferred to a petri-tetrafluoroethylene petri dish, and the petri dish was placed in a drier kept at 100 ° C. and dried for 3 hours. The obtained dry powder was pulverized and mixed, heated to 625 ° C. in an oxygen stream over 1 hour in an electric furnace, fired for 20 hours, and then cooled to near room temperature in the furnace to obtain a fired product. . The obtained fired product was pulverized, washed with distilled water, filtered, and dried at 100 ° C. to obtain a product.
　Ｘ線回折による評価
　上記で得られた生成物の実測（＋）及び計算（実線）Ｘ線回折パターンを図３に示す。また、リートベルト解析により、得られた生成物が層状岩塩型構造を有する六方晶ＬｉＮｉＯ２単相であること、格子定数ａが２．８６０１３（１０）Å、格子定数ｃが１４．１５０９（４）Å、格子体積が１００．２５０（６）Å３、ｃ／ａ値が４．９４８、Ｎｉ層内のＮｉ及びＳｎイオン占有率が８１．１２（１８）％、Ｌｉ層内のＮｉ及びＳｎイオン占有率が０．８３（６）％であることが分かった。 Evaluation by X-ray diffraction FIG. 3 shows an actual measurement (+) and calculation (solid line) X-ray diffraction pattern of the product obtained above. Further, by Rietveld analysis, the obtained product is a hexagonal LiNiO 2 single phase having a layered rock salt structure, the lattice constant a is 2.86013 (10) １０, and the lattice constant c is 14.1509 (4 ), Lattice volume is 100.250 (6) Å 3 , c / a value is 4.948, Ni and Sn ion occupancy in Ni layer is 81.12 (18)%, Ni and Sn in Li layer The ion occupancy was found to be 0.83 (6)%.
　化学分析
　ＩＣＰ発光分析により上記で得られた生成物の化学組成を求めたところ、Ｌｉ／（Ｎｉ＋Ｓｎ）比が１．１４、Ｓｎ／（Ｎｉ＋Ｓｎ）比が０．０１１であることが分かった。 When the chemical composition of the product obtained above was determined by chemical analysis ICP emission analysis, it was found that the Li / (Ni + Sn) ratio was 1.14 and the Sn / (Ni + Sn) ratio was 0.011.
　充放電特性評価
　上記で得られた生成物５ｍｇをアセチレンブラック５ｍｇと混合した後、ポリテトラフルオロエチレン０．５ｍｇを用いて正極合材を作製し、当該正極合材をアルミニウムメッシュに圧着して正極とした。次いで、当該正極、負極として金属リチウム、電解液として１Ｍ　ＬｉＰＦ６／ＥＣ＋ＤＭＣ系、及びセパレータを用いてコイン型電池を作製し、充放電試験を行った。充放電試験は充電開始で、電位範囲：２．２～４．８Ｖ、正極活物質あたりの電流密度：４０ｍＡ／ｇ、試験温度：３０℃の条件で５０サイクルまで行った。結果を図４に示す。 Evaluation of charge / discharge characteristics After 5 mg of the product obtained above was mixed with 5 mg of acetylene black, a positive electrode mixture was prepared using 0.5 mg of polytetrafluoroethylene, and the positive electrode mixture was pressure-bonded to an aluminum mesh to form a positive electrode It was. Next, a coin-type battery was fabricated using the positive electrode, metallic lithium as the negative electrode, 1M LiPF 6 / EC + DMC system as the electrolyte, and a separator, and a charge / discharge test was performed. The charge / discharge test was started at the start of charging, and was conducted up to 50 cycles under the conditions of potential range: 2.2 to 4.8 V, current density per positive electrode active material: 40 mA / g, test temperature: 30 ° C. The results are shown in FIG.
　図４より、実施例２で得られた生成物は、初期充電容量が２３６ｍＡｈ／ｇ、初期放電容量が２０１ｍＡｈ／ｇ、初期充放電効率が８４．８％、初期放電平均電圧が３．７２Ｖ、初期放電エネルギー密度が７４６ｍＷｈ／ｇ、５０サイクル後の放電容量が１７１ｍＡｈ／ｇ、５０サイクル後の放電容量維持率が７２．６％であることが分かった。 4, the product obtained in Example 2 has an initial charge capacity of 236 mAh / g, an initial discharge capacity of 201 mAh / g, an initial charge / discharge efficiency of 84.8%, an initial discharge average voltage of 3.72 V, It was found that the initial discharge energy density was 746 mWh / g, the discharge capacity after 50 cycles was 171 mAh / g, and the discharge capacity retention rate after 50 cycles was 72.6%.
　［実施例３］
　試料の調製
　水酸化リチウム１水和物２０．９８ｇ（０．５０ｍｏｌ）を２００ｍｌの蒸留水に加え完全に溶解させた。当該水酸化リチウム溶液に水酸化アルミニウム１．９５ｇ（０．０２５ｍｏｌ）を加えて完全に溶解させた後、水酸化ニッケル２０．８６ｇ（０．２２５ｍｏｌ）を加えて撹拌して分散させた。得られた混合物をポリテトラフルオロエチレン製シャーレに移し、当該シャーレを１００℃に保たれた乾燥機に入れ、３時間かけて乾燥を行った。得られた乾燥粉末を粉砕混合し、電気炉にて酸素気流中１時間かけて６５０℃に昇温し、２０時間焼成を行い、その後、炉内で室温付近まで冷却して焼成物を得た。得られた焼成物を粉砕後、蒸留水を用いて水洗処理を行った後、濾過し、１００℃で乾燥することにより生成物を得た。 [Example 3]
Sample Preparation 20.98 g (0.50 mol) of lithium hydroxide monohydrate was added to 200 ml of distilled water and completely dissolved. After 1.95 g (0.025 mol) of aluminum hydroxide was added to the lithium hydroxide solution and completely dissolved, 20.86 g (0.225 mol) of nickel hydroxide was added and dispersed by stirring. The obtained mixture was transferred to a petri-tetrafluoroethylene petri dish, and the petri dish was placed in a drier kept at 100 ° C. and dried for 3 hours. The obtained dry powder was pulverized and mixed, heated to 650 ° C. over 1 hour in an oxygen stream in an electric furnace, fired for 20 hours, and then cooled to near room temperature in the furnace to obtain a fired product. . The obtained fired product was pulverized, washed with distilled water, filtered, and dried at 100 ° C. to obtain a product.
　Ｘ線回折による評価
　上記で得られた生成物の実測（＋）及び計算（実線）Ｘ線回折パターンを図５に示す。また、リートベルト解析により、得られた生成物が層状岩塩型構造を有する六方晶ＬｉＮｉＯ２単相であること、格子定数ａが２．８６３０５（５）Å、格子定数ｃが１４．１８００（２）Å、格子体積が１００．６６２（３）Å３、ｃ／ａ値が４．９５３、Ｎｉ層内のＮｉ及びＡｌイオン占有率が９９．７８（１９）％、Ｌｉ層内のＮｉ及びＡｌイオン占有率が０．０９（７）％であることが分かった。 Evaluation by X-ray diffraction FIG. 5 shows an actual measurement (+) and calculation (solid line) X-ray diffraction pattern of the product obtained above. Further, by Rietveld analysis, the obtained product is a hexagonal LiNiO 2 single phase having a layered rock salt type structure, the lattice constant a is 2.86305 (5) Å, and the lattice constant c is 14.1800 (2 ), Lattice volume is 100.62 (3) Å 3 , c / a value is 4.953, Ni and Al ion occupancy in Ni layer is 99.78 (19)%, Ni and Al in Li layer The ion occupancy was found to be 0.09 (7)%.
　化学分析
　ＩＣＰ発光分析により上記で得られた生成物の化学組成を求めたところ、Ｌｉ／（Ｎｉ＋Ａｌ）比が１．００、Ａｌ／（Ｎｉ＋Ａｌ）比が０．０８１であることが分かった。 Chemical analysis When the chemical composition of the product obtained above was determined by ICP emission analysis, it was found that the Li / (Ni + Al) ratio was 1.00 and the Al / (Ni + Al) ratio was 0.081.
　充放電特性評価
　上記で得られた生成物５ｍｇをアセチレンブラック５ｍｇと混合した後、ポリテトラフルオロエチレン０．５ｍｇを用いて正極合材を作製し、当該正極合材をアルミニウムメッシュに圧着して正極とした。次いで、当該正極、負極として金属リチウム、電解液として１Ｍ　ＬｉＰＦ６／ＥＣ＋ＤＭＣ系、及びセパレータを用いてコイン型電池を作製し、充放電試験を行った。充放電試験は充電開始で、電位範囲：２．２～４．８Ｖ、正極活物質あたりの電流密度：４０ｍＡ／ｇ、試験温度：３０℃の条件で５０サイクルまで行った。結果を図６に示す。 Evaluation of charge / discharge characteristics After 5 mg of the product obtained above was mixed with 5 mg of acetylene black, a positive electrode mixture was prepared using 0.5 mg of polytetrafluoroethylene, and the positive electrode mixture was pressure-bonded to an aluminum mesh to form a positive electrode It was. Next, a coin-type battery was fabricated using the positive electrode, metallic lithium as the negative electrode, 1M LiPF 6 / EC + DMC system as the electrolyte, and a separator, and a charge / discharge test was performed. The charge / discharge test was started at the start of charging, and was conducted up to 50 cycles under the conditions of potential range: 2.2 to 4.8 V, current density per positive electrode active material: 40 mA / g, test temperature: 30 ° C. The results are shown in FIG.
　図６より、実施例３で得られた生成物は、初期充電容量が２３０ｍＡｈ／ｇ、初期放電容量が２０７ｍＡｈ／ｇ、初期充放電効率が９０．０％、初期放電平均電圧が３．７０Ｖ、初期放電エネルギー密度が７６６ｍＷｈ／ｇ、５０サイクル後の放電容量が１７１ｍＡｈ／ｇ、５０サイクル後の放電容量維持率が８２．６％であることが分かった。 6, the product obtained in Example 3 has an initial charge capacity of 230 mAh / g, an initial discharge capacity of 207 mAh / g, an initial charge / discharge efficiency of 90.0%, an initial discharge average voltage of 3.70 V, It was found that the initial discharge energy density was 766 mWh / g, the discharge capacity after 50 cycles was 171 mAh / g, and the discharge capacity retention rate after 50 cycles was 82.6%.
　［比較例１］
　試料の調製
　水酸化リチウム１水和物１０.７０ｇ（０．２５５ｍｏｌ）を２００ｍｌの蒸留水に加え完全に溶解させた。当該水酸化リチウム溶液に水酸化ニッケル２３．１８ｇ（０．２５ｍｏｌ）を加えて撹拌して分散させた。得られた混合物をポリテトラフルオロエチレン製シャーレに移し、当該シャーレを１００℃に保たれた乾燥機に入れ、３時間かけて乾燥を行った。得られた乾燥粉末を粉砕混合し、電気炉にて酸素気流中１時間かけて７００℃に昇温し、２０時間焼成を行い、その後、炉内で室温付近まで冷却して焼成物を得た。得られた焼成物を粉砕後、再度、電気炉にて酸素気流中１時間かけて７５０℃に昇温し、２０時間焼成を行い、その後、炉内で室温付近まで冷却して焼成物を得た。得られた焼成物を粉砕後、蒸留水を用いて水洗処理を行った後、濾過し、１００℃で乾燥することにより生成物を得た。 [Comparative Example 1]
Sample Preparation 10.70 g (0.255 mol) of lithium hydroxide monohydrate was added to 200 ml of distilled water and completely dissolved. To the lithium hydroxide solution, 23.18 g (0.25 mol) of nickel hydroxide was added and dispersed by stirring. The obtained mixture was transferred to a petri-tetrafluoroethylene petri dish, and the petri dish was placed in a drier kept at 100 ° C. and dried for 3 hours. The obtained dry powder was pulverized and mixed, heated to 700 ° C. over 1 hour in an oxygen stream in an electric furnace, fired for 20 hours, and then cooled to near room temperature in the furnace to obtain a fired product. . After the obtained fired product is pulverized, the temperature is again raised to 750 ° C. in an oxygen stream over 1 hour in an electric furnace, fired for 20 hours, and then cooled to near room temperature in the furnace to obtain a fired product. It was. The obtained fired product was pulverized, washed with distilled water, filtered, and dried at 100 ° C. to obtain a product.
　Ｘ線回折による評価
　上記で得られた生成物の実測（＋）及び計算（実線）Ｘ線回折パターンを図７に示す。また、リートベルト解析により、得られた生成物が層状岩塩型構造を有する六方晶ＬｉＮｉＯ２単相であること、格子定数ａが２．８７５８９（３）Å、格子定数ｃが１４．１９１５０（１３）Å、格子体積が１００．６４８９（１８）Å３、ｃ／ａ値が４．９３５、Ｎｉ層内のＮｉイオン占有率が１００％、Ｌｉ層内のＮｉイオン占有率が０．５６（５）％であることが分かった。 Evaluation by X-ray diffraction FIG. 7 shows an actual measurement (+) and calculation (solid line) X-ray diffraction pattern of the product obtained above. Further, by Rietveld analysis, the obtained product is a hexagonal LiNiO 2 single phase having a layered rock salt structure, the lattice constant a is 2.87589 (3) Å, and the lattice constant c is 14.19150 (13 ), Lattice volume is 100.6489 (18) 3 , c / a value is 4.935, Ni ion occupancy in Ni layer is 100%, Ni ion occupancy in Li layer is 0.56 (5 )%.
　化学分析
　ＩＣＰ発光分析により上記で得られた生成物の化学組成を求めたところ、Ｌｉ／Ｎｉ比が１．０２であることが分かった。 Chemical analysis When the chemical composition of the product obtained above was determined by ICP emission analysis, the Li / Ni ratio was found to be 1.02.
　充放電特性評価
　上記で得られた生成物５ｍｇをアセチレンブラック５ｍｇと混合した後、ポリテトラフルオロエチレン０．５ｍｇを用いて正極合材を作製し、当該正極合材をアルミニウムメッシュに圧着して正極とした。次いで、当該正極、負極として金属リチウム、電解液として１Ｍ　ＬｉＰＦ６／ＥＣ＋ＤＭＣ系、及びセパレータを用いてコイン型電池を作製し、充放電試験を行った。充放電試験は充電開始で、電位範囲：２．２～４．８Ｖ、正極活物質あたりの電流密度：４０ｍＡ／ｇ、試験温度：３０℃の条件で５０サイクルまで行った。結果を図８に示す。 Evaluation of charge / discharge characteristics After 5 mg of the product obtained above was mixed with 5 mg of acetylene black, a positive electrode mixture was prepared using 0.5 mg of polytetrafluoroethylene, and the positive electrode mixture was pressure-bonded to an aluminum mesh to form a positive electrode It was. Next, a coin-type battery was fabricated using the positive electrode, metallic lithium as the negative electrode, 1M LiPF 6 / EC + DMC system as the electrolyte, and a separator, and a charge / discharge test was performed. The charge / discharge test was started at the start of charging, and was conducted up to 50 cycles under the conditions of potential range: 2.2 to 4.8 V, current density per positive electrode active material: 40 mA / g, test temperature: 30 ° C. The results are shown in FIG.
　図８より、比較例１で得られた生成物は、初期充電容量が２５９ｍＡｈ／ｇ、初期放電容量が２２０ｍＡｈ／ｇ、初期充放電効率が８４．６％、初期放電平均電圧が３．８０Ｖ、初期放電エネルギー密度が８３４ｍＷｈ／ｇ、３０サイクル後の放電容量が１７６ｍＡｈ／ｇ、３０サイクル後の放電容量維持率が８０．４％、５０サイクル後の放電容量が１５９ｍＡｈ／ｇ、５０サイクル後の放電容量維持率が７２．６％であることが分かった。 From FIG. 8, the product obtained in Comparative Example 1 has an initial charge capacity of 259 mAh / g, an initial discharge capacity of 220 mAh / g, an initial charge / discharge efficiency of 84.6%, an initial discharge average voltage of 3.80 V, Initial discharge energy density is 834 mWh / g, discharge capacity after 30 cycles is 176 mAh / g, discharge capacity maintenance rate after 30 cycles is 80.4%, discharge capacity after 50 cycles is 159 mAh / g, discharge after 50 cycles The capacity retention rate was found to be 72.6%.
　［実施例４］
　試料の調製
　硝酸ニッケル（ＩＩ）６水和物と硝酸コバルト（ＩＩ）６水和物を８０：１５のモル比（０．２５ｍｏｌ／バッチ）となるように秤量し、蒸留水５００ｍｌに溶解させ、金属塩水溶液を調製した。次いで、水酸化ナトリウム５０ｇの入った別の容器に蒸留水５００ｍｌを加えて完全に溶解させ、恒温槽にて２０℃に保持した。水酸化ナトリウム水溶液に対して、上記で調製した金属塩水溶液を約３時間かけて徐々に滴下し、共沈物を作製した。その後、酸素ガス発生器を用いて共沈物を室温にて２日間バブリング処理を行うことにより沈殿を熟成した。熟成後、沈殿を水洗及び濾過して焼成用原料とした。 [Example 4]
Sample Preparation Nickel (II) nitrate hexahydrate and cobalt (II) nitrate hexahydrate were weighed to a molar ratio of 80:15 (0.25 mol / batch), dissolved in 500 ml of distilled water, An aqueous metal salt solution was prepared. Next, 500 ml of distilled water was added to another container containing 50 g of sodium hydroxide and completely dissolved, and kept at 20 ° C. in a thermostatic bath. The aqueous metal salt solution prepared above was gradually added dropwise to the aqueous sodium hydroxide solution over about 3 hours to produce a coprecipitate. Thereafter, the coprecipitate was subjected to a bubbling treatment at room temperature for 2 days using an oxygen gas generator to ripen the precipitate. After aging, the precipitate was washed with water and filtered to obtain a raw material for firing.
　水酸化リチウム１水和物２０．９８ｇ（０．５０ｍｏｌ）を２００ｍｌの蒸留水に加え完全に溶解させた。当該水酸化リチウム溶液に水酸化アルミニウム０．９８ｇ（０．０１２５ｍｏｌ）を加えて完全に溶解させた後、上記で作成した焼成用原料を加えてミキサー撹拌して分散させた。得られた混合物をポリテトラフルオロエチレン製シャーレに移し、当該シャーレを５０℃に保たれた乾燥機に入れ、２日間かけて乾燥を行った。得られた乾燥粉末を粉砕混合し、電気炉にて酸素気流中１時間かけて５００℃に昇温し、２０時間焼成を行い、その後、炉内で室温付近まで冷却して焼成物を得た。得られた焼成物を粉砕後、再び電気炉にて酸素気流中１時間かけて７００℃に昇温し、２０時間焼成を行い、その後、炉内で室温付近まで冷却をして焼成物を得た。蒸留水を用いて水洗処理を行った後、濾過し、１００℃で乾燥することにより生成物を得た。 Lithium hydroxide monohydrate 20.98 g (0.50 mol) was added to 200 ml of distilled water and completely dissolved. After 0.98 g (0.0125 mol) of aluminum hydroxide was added to the lithium hydroxide solution and completely dissolved, the firing raw material prepared above was added and dispersed by stirring with a mixer. The obtained mixture was transferred to a petri-tetrafluoroethylene petri dish, and the petri dish was placed in a drier kept at 50 ° C. and dried for 2 days. The obtained dry powder was pulverized and mixed, heated to 500 ° C. over 1 hour in an oxygen stream in an electric furnace, fired for 20 hours, and then cooled to near room temperature in the furnace to obtain a fired product. . After pulverizing the obtained fired product, the temperature was again raised to 700 ° C. in an oxygen stream over 1 hour in an electric furnace, fired for 20 hours, and then cooled to near room temperature in the furnace to obtain a fired product. It was. After performing the water washing process using distilled water, it filtered, and the product was obtained by drying at 100 degreeC.
　Ｘ線回折による評価
　上記で得られた生成物の実測（＋）及び計算（実線）Ｘ線回折パターンを図９に示す。また、リートベルト解析により、得られた生成物が層状岩塩型構造を有する六方晶ＬｉＮｉＯ２単相であること、格子定数ａが２．８５５２２（６）Å、格子定数ｃが１４．１４７３（３）Å、格子体積が９９．８８１（４）Å３、ｃ／ａ値が４．９５５、Ｎｉ層内のＮｉ、Ａｌ、及びＣｏイオン占有率が９８．０（３）％、Ｌｉ層内のＮｉ、Ａｌ、及びＣｏイオンの占有率が０％であることが分かった。 Evaluation by X-ray diffraction FIG. 9 shows an actual measurement (+) and calculation (solid line) X-ray diffraction pattern of the product obtained above. Further, the Rietveld analysis shows that the obtained product is a hexagonal LiNiO 2 single phase having a layered rock salt structure, the lattice constant a is 2.85522 (6) Å, and the lattice constant c is 14.1473 (3 ), Lattice volume is 99.881 (4) Å 3 , c / a value is 4.955, Ni, Al, and Co ion occupancy in Ni layer is 98.0 (3)%, in Li layer It was found that the occupation ratio of Ni, Al, and Co ions was 0%.
　充放電特性評価
　上記で得られた生成物５ｍｇをアセチレンブラック５ｍｇと混合した後、ポリテトラフルオロエチレン０．５ｍｇを用いて正極合材を作製し、当該正極合材をアルミニウムメッシュに圧着して正極とした。次いで、当該正極、負極として金属リチウム、電解液として１Ｍ　ＬｉＰＦ６／ＥＣ＋ＤＭＣ系、及びセパレータを用いてコイン型電池を作製し、充放電試験を行った。充放電試験は充電開始で、電位範囲：２．２～４．８Ｖ（２サイクル目以降：２．２～４．６Ｖ）、正極活物質あたりの電流密度：４０ｍＡ／ｇ、試験温度：３０℃の条件で３０サイクルまで行った。結果を図１０に示す。 Evaluation of charge / discharge characteristics After 5 mg of the product obtained above was mixed with 5 mg of acetylene black, a positive electrode mixture was prepared using 0.5 mg of polytetrafluoroethylene, and the positive electrode mixture was pressure-bonded to an aluminum mesh to form a positive electrode It was. Next, a coin-type battery was fabricated using the positive electrode, metallic lithium as the negative electrode, 1M LiPF 6 / EC + DMC system as the electrolyte, and a separator, and a charge / discharge test was performed. The charge / discharge test is the start of charging, with a potential range of 2.2 to 4.8 V (second and subsequent cycles: 2.2 to 4.6 V), current density per positive electrode active material: 40 mA / g, test temperature: 30 ° C. Up to 30 cycles were performed under the following conditions. The results are shown in FIG.
　図１０より、実施例４で得られた生成物は、初期充電容量が２０９ｍＡｈ／ｇ、初期放電容量が１５３ｍＡｈ／ｇ、初期充放電効率が７３．２％、初期放電平均電圧が３．５５Ｖ、初期放電エネルギー密度が５６６ｍＷｈ／ｇ、３０サイクル後の放電容量が１２６ｍＡｈ／ｇ、３０サイクル後の放電容量維持率が８２．４％であることが分かった。 10, the product obtained in Example 4 has an initial charge capacity of 209 mAh / g, an initial discharge capacity of 153 mAh / g, an initial charge / discharge efficiency of 73.2%, an initial discharge average voltage of 3.55 V, It was found that the initial discharge energy density was 566 mWh / g, the discharge capacity after 30 cycles was 126 mAh / g, and the discharge capacity retention rate after 30 cycles was 82.4%.
　［実施例５］
　試料の調製
　硝酸ニッケル（ＩＩ）６水和物と塩化マンガン（ＩＩ）４水和物を７：３のモル比（０．２５ｍｏｌ／バッチ）となるように秤量し、蒸留水５００ｍｌに溶解させ、金属塩水溶液を調製した。次いで、水酸化ナトリウム５０ｇの入った別の容器に蒸留水５００ｍｌを加えて完全に溶解させ、恒温槽にて２０℃に保持した。水酸化ナトリウム水溶液に対して、上記で調製した金属塩水溶液を約３時間かけて徐々に滴下し、共沈物を作製した。その後、酸素ガス発生器を用いて共沈物を室温にて２日間バブリング処理を行うことにより沈殿を熟成した。熟成後、沈殿を水洗及び濾過して焼成用原料とした。 [Example 5]
Sample preparation Nickel (II) nitrate hexahydrate and manganese (II) chloride tetrahydrate were weighed to a molar ratio of 7: 3 (0.25 mol / batch), dissolved in 500 ml of distilled water, An aqueous metal salt solution was prepared. Next, 500 ml of distilled water was added to another container containing 50 g of sodium hydroxide and completely dissolved, and kept at 20 ° C. in a thermostatic bath. The aqueous metal salt solution prepared above was gradually added dropwise to the aqueous sodium hydroxide solution over about 3 hours to produce a coprecipitate. Thereafter, the coprecipitate was subjected to a bubbling treatment at room temperature for 2 days using an oxygen gas generator to ripen the precipitate. After aging, the precipitate was washed with water and filtered to obtain a raw material for firing.
　水酸化リチウム１水和物２０．９８ｇ（０．５０ｍｏｌ）を２００ｍｌの蒸留水に加え完全に溶解させた。当該水酸化リチウム溶液に上記で作成した焼成用原料を加えてミキサー撹拌して分散させた。得られた混合物をポリテトラフルオロエチレン製シャーレに移し、当該シャーレを５０℃に保たれた乾燥機に入れ、２日間かけて乾燥を行った。得られた乾燥粉末を粉砕混合し、電気炉にて酸素気流中１時間かけて５００℃に昇温し、２０時間焼成を行い、その後、炉内で室温付近まで冷却して焼成物を得た。得られた焼成物を粉砕後、再び電気炉にて酸素気流中１時間かけて７５０℃に昇温し、２０時間焼成を行い、その後、炉内で室温付近まで冷却をして焼成物を得た。蒸留水を用いて水洗処理を行った後、濾過し、１００℃で乾燥することにより生成物を得た。 Lithium hydroxide monohydrate 20.98 g (0.50 mol) was added to 200 ml of distilled water and completely dissolved. The firing raw material prepared above was added to the lithium hydroxide solution and dispersed by stirring with a mixer. The obtained mixture was transferred to a petri-tetrafluoroethylene petri dish, and the petri dish was placed in a drier kept at 50 ° C. and dried for 2 days. The obtained dry powder was pulverized and mixed, heated to 500 ° C. over 1 hour in an oxygen stream in an electric furnace, fired for 20 hours, and then cooled to near room temperature in the furnace to obtain a fired product. . After the obtained fired product is pulverized, the temperature is again raised to 750 ° C. in an oxygen stream over 1 hour in an electric furnace, fired for 20 hours, and then cooled to near room temperature in the furnace to obtain a fired product. It was. After performing the water washing process using distilled water, it filtered, and the product was obtained by drying at 100 degreeC.
　Ｘ線回折による評価
　上記で得られた生成物の実測（＋）及び計算（実線）Ｘ線回折パターンを図１１に示す。なお、図１１の右上部は、回折角２θが１７～３２°付近を拡大したものである。また、リートベルト解析により、得られた生成物が層状岩塩型構造を有する単斜晶Ｌｉ２ＭｎＯ３単相であることが分かった。また、当該生成物の結晶相が単斜晶であることは、図１１の右上部に示される通り、回折角２θが２０～３０°の範囲において小さな超格子ピークが存在することにより確認された。さらに、リートベルト解析により、格子定数ａが４．９４２５（５）Å、格子定数ｂが８．５７５１（６）Å、格子定数ｃが５．００９９（３）Å、βが１０９．２２０（９）°、格子体積が２００．５（６）Å３、Ｎｉ層内のＮｉ及びＭｎイオン占有率が７９．２（４）％、Ｌｉ層内のＮｉ及びＭｎイオン占有率が２．５２（７）％であることが分かった。 Evaluation by X-ray diffraction FIG. 11 shows an actual measurement (+) and calculation (solid line) X-ray diffraction pattern of the product obtained above. In the upper right part of FIG. 11, the diffraction angle 2θ is enlarged in the vicinity of 17 to 32 °. Further, Rietveld analysis revealed that the obtained product was a monoclinic Li 2 MnO 3 single phase having a layered rock salt structure. Further, the fact that the crystal phase of the product is monoclinic was confirmed by the presence of a small superlattice peak in the diffraction angle 2θ range of 20 to 30 ° as shown in the upper right part of FIG. . Further, by Rietveld analysis, the lattice constant a is 4.9425 (5) Å, the lattice constant b is 8.5575 (6) Å, the lattice constant c is 5.0099 (3) Å, and β is 109.220 (9 ) °, lattice volume 200.5 (6) Å 3 , Ni and Mn ion occupancy in Ni layer 79.2 (4)%, Ni and Mn ion occupancy in Li layer 2.52 (7 )%.
　充放電特性評価
　上記で得られた生成物５ｍｇをアセチレンブラック５ｍｇと混合した後、ポリテトラフルオロエチレン０．５ｍｇを用いて正極合材を作製し、当該正極合材をアルミニウムメッシュに圧着して正極とした。次いで、当該正極、負極として金属リチウム、電解液として１Ｍ　ＬｉＰＦ６／ＥＣ＋ＤＭＣ系、及びセパレータを用いてコイン型電池を作製し、充放電試験を行った。充放電試験は充電開始で、電位範囲：２．２～４．８Ｖ、正極活物質あたりの電流密度：４０ｍＡ／ｇ、試験温度：３０℃の条件で５０サイクルまで行った。結果を図１２に示す。 Evaluation of charge / discharge characteristics After 5 mg of the product obtained above was mixed with 5 mg of acetylene black, a positive electrode mixture was prepared using 0.5 mg of polytetrafluoroethylene, and the positive electrode mixture was pressure-bonded to an aluminum mesh to form a positive electrode It was. Next, a coin-type battery was fabricated using the positive electrode, metallic lithium as the negative electrode, 1M LiPF 6 / EC + DMC system as the electrolyte, and a separator, and a charge / discharge test was performed. The charge / discharge test was started at the start of charging, and was conducted up to 50 cycles under the conditions of potential range: 2.2 to 4.8 V, current density per positive electrode active material: 40 mA / g, test temperature: 30 ° C. The results are shown in FIG.
　図１２より、実施例５で得られた生成物は、初期充電容量が１６２ｍＡｈ／ｇ、初期放電容量が１２５ｍＡｈ／ｇ、初期充放電効率が７７．２％、初期放電平均電圧が３．７３Ｖ、初期放電エネルギー密度が４６９ｍＷｈ／ｇ、５０サイクル後の放電容量が１０３ｍＡｈ／ｇ、５０サイクル後の放電容量維持率が８２．０％であることが分かった。 From FIG. 12, the product obtained in Example 5 has an initial charge capacity of 162 mAh / g, an initial discharge capacity of 125 mAh / g, an initial charge / discharge efficiency of 77.2%, an initial discharge average voltage of 3.73 V, It was found that the initial discharge energy density was 469 mWh / g, the discharge capacity after 50 cycles was 103 mAh / g, and the discharge capacity retention rate after 50 cycles was 82.0%.
　［結果及び考察］
　以上の実施例１～５及び比較例１の試料のＸ線回折による評価結果及び化学分析結果を下記表１に、充放電特性評価の結果を下記表２に示す。 [Results and discussion]
The evaluation results by X-ray diffraction and the chemical analysis results of the samples of Examples 1 to 5 and Comparative Example 1 are shown in Table 1 below, and the results of charge / discharge characteristic evaluation are shown in Table 2 below.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
　以上の結果から、実施例１の試料は、比較例１の試料と比較して、初期充放電容量、初期放電平均電圧、及び初期放電エネルギー密度はほぼ同等であり、初期充放電効率、５０サイクル後の放電容量、及び５０サイクル後の放電容量維持率が優れることが分かった。 From the above results, the sample of Example 1 has almost the same initial charge / discharge capacity, initial discharge average voltage, and initial discharge energy density as compared with the sample of Comparative Example 1, and the initial charge / discharge efficiency, 50 cycles. It was found that the subsequent discharge capacity and the discharge capacity retention rate after 50 cycles were excellent.
　また、実施例２及び３の試料は、比較例１の試料と比較して、初期充放電容量、初期放電平均電圧、及び初期放電エネルギー密度はやや劣るもののリチウムイオン二次電池用正極材料として十分使用可能な水準であり、初期充放電効率はほぼ同等であり、５０サイクル後の放電容量、及び５０サイクル後の放電容量維持率が優れていることが分かった。 In addition, the samples of Examples 2 and 3 are sufficient as positive electrode materials for lithium ion secondary batteries although initial charge / discharge capacity, initial discharge average voltage, and initial discharge energy density are slightly inferior to those of Comparative Example 1. It was a usable level, the initial charge and discharge efficiency was almost the same, and it was found that the discharge capacity after 50 cycles and the discharge capacity maintenance rate after 50 cycles were excellent.
　実施例４の試料は、比較例１の試料と比較して、初期充放電容量、初期充放電効率、初期放電平均電圧、及び初期放電エネルギー密度は劣るもののリチウムイオン二次電池用正極用材料として使用可能な水準であり、３０サイクル後の放電容量維持率が優れていることが分かった。 Although the sample of Example 4 is inferior to the sample of Comparative Example 1 in initial charge / discharge capacity, initial charge / discharge efficiency, initial discharge average voltage, and initial discharge energy density, it is a positive electrode material for a lithium ion secondary battery. It was a usable level, and it was found that the discharge capacity retention rate after 30 cycles was excellent.
　実施例５の試料は、比較例１の試料と比較して、初期充放電容量、初期充放電効率、初期放電平均電圧、及び初期放電エネルギー密度は劣るもののリチウムイオン二次電池用正極用材料として使用可能な水準であり、５０サイクル後の放電容量維持率が優れていることが分かった。 The sample of Example 5 is inferior to the sample of Comparative Example 1 in terms of initial charge / discharge capacity, initial charge / discharge efficiency, initial discharge average voltage, and initial discharge energy density, but as a positive electrode material for a lithium ion secondary battery. It was found that this was a usable level and the discharge capacity retention rate after 50 cycles was excellent.

Claims (8)

  1. 一般式（１）：
    Ｌｉｘ（Ｎｉ１－ｙＭｙ）Ｏ２＋δ　　　　　（１）
    ［式中、ＭはＧｅ、Ｓｎ、Ａｌ、Ｃｏ、及びＭｎからなる群から選択される少なくとも１種を示す。ｘ、ｙ及びδはそれぞれ、０．８≦ｘ≦１．４、０＜ｙ≦０．５００、－０．２０≦δ≦０．２０を示す。］
    で表される、リチウムニッケル系複合酸化物。     General formula (1):
    Li x (Ni 1-y M y ) O 2 + δ (1)
    [Wherein M represents at least one selected from the group consisting of Ge, Sn, Al, Co, and Mn. x, y, and δ represent 0.8 ≦ x ≦ 1.4, 0 <y ≦ 0.500, and −0.20 ≦ δ ≦ 0.20, respectively. ]
    Lithium nickel composite oxide represented by
  2. ＭがＧｅ、Ｓｎ、Ａｌ若しくはＭｎであるか、Ａｌ及びＣｏの組合せである、請求項１に記載のリチウムニッケル系複合酸化物。 The lithium nickel-based composite oxide according to claim 1, wherein M is Ge, Sn, Al, or Mn, or a combination of Al and Co.
  3. 六方晶層状岩塩型構造の結晶相又は単斜晶層状岩塩型構造の結晶相を含む、請求項１又は２に記載のリチウムニッケル系複合酸化物。 3. The lithium nickel composite oxide according to claim 1, comprising a crystal phase of a hexagonal layered rock salt structure or a crystal phase of a monoclinic layered rock salt structure.
  4. 六方晶層状岩塩型構造の結晶相又は単斜晶層状岩塩型構造の結晶相のみからなる、請求項３に記載のリチウムニッケル系複合酸化物。 The lithium nickel composite oxide according to claim 3, comprising only a crystal phase of a hexagonal layered rock salt type structure or a crystal phase of a monoclinic layered rock salt type structure.
  5. 請求項１～４のいずれかに記載のリチウムニッケル系複合酸化物の製造方法であって、
    水性溶媒中で、リチウム化合物と、金属Ｍ化合物と、水酸化ニッケル及び／又は水溶性ニッケル塩とを混合する第１工程、及び
    前記第１工程により得られた混合物を酸化性雰囲気下で焼成する第２工程
    を含む、製造方法。     A method for producing a lithium nickel composite oxide according to any one of claims 1 to 4,
    A first step in which a lithium compound, a metal M compound, nickel hydroxide and / or a water-soluble nickel salt are mixed in an aqueous solvent, and the mixture obtained in the first step is fired in an oxidizing atmosphere. A manufacturing method including a 2nd process.
  6. 前記第１工程が、リチウム化合物を含む水溶液に、金属Ｍ化合物と、水酸化ニッケル及び／又は水溶性ニッケル塩とを添加する工程である、請求項５に記載の製造方法。 The manufacturing method according to claim 5, wherein the first step is a step of adding a metal M compound and nickel hydroxide and / or a water-soluble nickel salt to an aqueous solution containing a lithium compound.
  7. 請求項１～４のいずれかに記載のリチウムニッケル系複合酸化物を含む、リチウムイオン二次電池用正極材料。 A positive electrode material for a lithium ion secondary battery, comprising the lithium nickel composite oxide according to any one of claims 1 to 4.
  8. 請求項７に記載のリチウムイオン二次電池用正極材料を含む、リチウムイオン二次電池。 The lithium ion secondary battery containing the positive electrode material for lithium ion secondary batteries of Claim 7.
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