Method for producing lithium-metal composite oxide

Abstract

This invention provides a method comprising a precursor mixing step wherein lithium hydroxide powder and precursor metal compound are mixed and a firing step wherein the obtained precursor mixture is fired. The lithium hydroxide powder has a particle size distribution of 1-1000 µm, a first peak where a peak top frequency exhibits a maximum value, and a second peak where the peak top frequency exhibits a maximum value among peaks showing a peak top at particle sizes at least 50 µm away from the particle size at the first peak, a ratio of the frequency at the second peak to the frequency at the first peak is 0.2-0.95, and the loose bulk density is 0.10 g / cm3-0.45 g / cm3. The precursor mixture which is used has a loose bulk density of 0.95 g / cm3 or less, and a ratio of packing density to loose bulk density of 1.10 or more.

Description

[0001] 241051W001

[0002] 1

[0003] METHOD FOR PRODUCING LITHIUM-METAL COMPOSITE OXIDE

[0004] TECHNICAL FIELD

[0005] The present disclosure relates to a method for producing a lithium-metal composite oxide.

[0006] BACKGROUND

[0007] Lithium ion secondary batteries are small and lightweight, and also have a high energy density, a high charge / discharge voltage, and a substantial charging / discharging capacity, and have thus garnered attention as power sources for operating AV devices or personal computers and other such electronic devices.

[0008] Lithium ion secondary batteries in which layered or spinel type lithium transition metal composite oxides are employed as the positive electrode active material can provide a high voltage level of 4 volts, and are therefore increasingly being put to practical use as high-energy density batteries. Examples of materials that have been primarily proposed include: relatively easy-to-synthesize lithium-cobalt composite oxides (LiCoO2); lithium-nickel composite oxides (LiNiC>2) obtained using nickel, which is less expensive than cobalt; lithium-nickel-cobalt- manganese composite oxides (LiNii / sCoi / sMni / sCh); and lithium-manganese composite oxides (LiMn2C>4) obtained using manganese.

[0009] Such lithium-metal composite oxides can generally be produced by mixing a lithium source and a metal source such as nickel, and then firing the mixture. The positive electrodes of the lithium ion secondary batteries here are formed by, for example, mixing a positive electrode active material with a binder such as polyvinylidene fluoride (PVDF) or a solvent such as N-methyl-2- pyrrolidone (NMP) into the form of a positive electrode mix paste, which is applied to a current collector made of aluminum foil, for example. Any lithium that is released at that time from the lithium-metal composite oxide in the positive electrode mix paste may react with moisture in the binder, for example, resulting in lithium hydroxide.

[0010] As lithium hydroxide production increases in this way, reactions between the lithium hydroxide and binder can result in the gelation of the positive electrode mix paste. The gelation of the positive electrode mix paste leads to poor handling during the manufacturing process and to lower yields. This tendency becomes quite pronounced when the proportion of lithium in the lithium-transition metal composite oxide serving as the positive electrode active material is in excess of the stoichiometric ratio relative to the transition metal, especially when there is a high proportion of nickel in the transition metal.

[0011] The release of lithium here may possibly come from the portion of lithium that has not been incorporated into the crystal lattice of the lithium-metal composite oxide, as well as from lithium that has been incorporated into the crystal lattice of the lithium-metal composite oxide. When 241051W001

[0012] 2 the lithium that has been incorporated into the crystal lattice of the lithium-metal composite oxide is eluted, increases in the resistance of the lithium-metal composite oxide can lower the charging / discharging efficiency.

[0013] The fired material is washed with water to remove the portion of the lithium that has not been incorporated into the crystal lattice of the lithium-metal composite oxide, as disclosed in JP2005-97087A, for example.

[0014] However, when lithium-metal composite oxides are washed with water in an attempt to remove the lithium, as in JP2005-97087A, ion-proton exchange in the lithium that has been incorporated into the crystal lattice results in either the loss of lithium on the surface of the lithium-metal composite oxide or in rock-salt phase conversion of the surface of the lithium-metal composite oxide, leading to a lower lithium ion secondary battery charging / discharging capacity.

[0015] Furthermore, there may be a deterioration in producibility because the precursor mixture cannot be tightly packed in a sheath during firing, depending on the properties of the lithium source and the source of metals such as nickel. On the other hand, when the precursor mixture is tightly packed in the sheath, oxygen and heat may not sufficiently reach the precursor mixture inside, which may cause a reduction in the quality of the resulting lithium-metal composite oxide and a reduction in charging / discharging capacity of the lithium ion secondary battery.

[0016] SUMMARY OF THE INVENTION

[0017] In view of the circumstances noted above, an objective of the present disclosure lies in providing a method for producing a lithium-metal composite oxide that enables a lithium-metal composite oxide to be produced at a high yield and, when the lithium-metal composite oxide is used as a positive electrode active material in a nonaqueous electrolyte secondary battery such as a lithium ion secondary battery, enables the nonaqueous electrolyte secondary battery to demonstrate superior charging / discharging capacity.

[0018] The inventors of the present invention engaged in extensive research to solve the problems noted above. As a result, it was found that a lithium-metal composite oxide could be produced at a high yield, such that when the lithium-metal composite oxide is used as a positive electrode active material, a nonaqueous electrolyte secondary battery in which the lithium-metal composite oxide is used demonstrates superior charging / discharging capacity, by virtue of a production method comprising: a precursor mixing step in which a precursor mixture is obtained by mixing a lithium hydroxide powder and a precursor metal compound comprising at least a transition metal; and a firing step in which a lithium-metal composite oxide is obtained by firing the precursor mixture, wherein, in the precursor mixing step, the lithium hydroxide powder which is used has, in a particle size range of 1 pm-1000 pm of a particle size distribution obtained by performing dry laser diffraction measurement, a first peak where a peak top frequency value 241051W001

[0019] 3 exhibits a maximum value, and a second peak where the peak top frequency value exhibits a maximum value among peaks showing a peak top at particle sizes at least 50 pm away from the particle size showing the peak top of the first peak, a ratio of the peak top frequency value of the second peak to the peak top frequency value of the first peak (peak top frequency value of second peak / peak top frequency value of first peak) is 0.2-0.95, the loose bulk density is 0.10 g / cm3-0.45 g / cm3, and the precursor mixture is adjusted so that the loose bulk density thereof is 0.95 g / cm3or less, and so that a ratio of packing density to loose bulk density (sheath packing density / loose bulk density) is 1.10 or more. Specifically, the present disclosure provides the following.

[0020] (1) A method for producing a lithium-metal composite oxide, the method comprising: a precursor mixing step in which a precursor mixture is obtained by mixing a lithium hydroxide powder and a precursor metal compound comprising at least a transition metal; and a firing step in which a lithium-metal composite oxide is obtained by firing the precursor mixture, wherein, in the precursor mixing step, the lithium hydroxide powder which is used has, in a particle size range of 1 pm-1000 pm of a particle size distribution obtained by performing dry laser diffraction measurement, a first peak where a peak top frequency value exhibits a maximum value, and a second peak where the peak top frequency value exhibits a maximum value among peaks showing a peak top at particle sizes at least 50 pm away from the particle size showing the peak top of the first peak, a ratio of the peak top frequency value of the second peak to the peak top frequency value of the first peak (peak top frequency value of second peak / peak top frequency value of first peak) is 0.2-0.95, and the loose bulk density is 0.10 g / cm3-0.45 g / cm3, and the precursor mixture is adjusted so that the loose bulk density thereof is 0.95 g / cm3or less, and so that a ratio of packing density to loose bulk density (sheath packing density / loose bulk density) is 1.1 or more.

[0021] (2) The method for producing a lithium-metal composite oxide as disclosed in (1), wherein the lithium-metal composite oxide is represented by the general formula LiaNixCoyMnzMwOa (in the formula, M is one or more elements other than Li, Ni, Co, Mn and O; 0.90<a<1.15; x+y+z+w=1.00; and 1.60<a<2.40).

[0022] The present disclosure makes it possible to provide a method for producing a lithium-metal composite oxide that enables a lithium-metal composite oxide to be produced at a high yield and, when the lithium-metal composite oxide is used as a positive electrode active material in a nonaqueous electrolyte secondary battery such as a lithium ion secondary battery, enables the nonaqueous electrolyte secondary battery to demonstrate superior charging / discharging capacity.

[0023] Embodiments of the present disclosure are described below, but the present disclosure is not 241051W001

[0024] 4 limited in any way by the description of the embodiments and can be carried out with additional modifications, as appropriate.

[0025] A method for producing a lithium-metal composite oxide according to an embodiment of the present disclosure comprises: a precursor mixing step in which a precursor mixture is obtained by mixing a lithium hydroxide powder and a precursor metal compound comprising at least a transition metal; and a firing step in which a lithium-metal composite oxide is obtained by firing the precursor mixture. In the precursor mixing step, the lithium hydroxide powder which is used has, in a particle size range of 1 pm-1000 pm of a particle size distribution obtained by performing dry laser diffraction measurement, a first peak where a peak top frequency value exhibits a maximum value, and a second peak where the peak top frequency value exhibits a maximum value among peaks showing a peak top at particle sizes at least 50 pm away from the particle size showing the peak top of the first peak, a ratio of the peak top frequency value of the second peak to the peak top frequency value of the first peak (peak top frequency value of second peak / peak top frequency value of first peak) is 0.2-0.95, the loose bulk density is 0.10 g / cm3-0.45 g / cm3, and the precursor mixture is adjusted so that the loose bulk density thereof is 0.95 g / cm3or less, and so that a ratio of packing density to loose bulk density (sheath packing density / loose bulk density) is 1.10 or more.

[0026] By virtue of such a production method, there are more sites of contact between the lithium compound and the precursor compound in the precursor mixture, so the lithiation reaction progresses more evenly during firing, and it is therefore possible to reduce the amount of residual lithium in the lithium-metal composite oxide, and to improve battery characteristics. Furthermore, the particle size distribution of the lithium hydroxide, and the loose bulk density and packing density of the precursor mixture constituting a mixture with the precursor compound are controlled to predetermined values, thereby making it possible to inhibit scattering of lithium hydroxide due to the flow of air in the firing furnace during firing, so it is possible to reduce a mismatch between the composition of the lithium-metal composite oxide (reduction in amount of lithium) and the prescribed proportions of metals. In addition, the precursor mixture obtained in this way has a high packing density in relation to loose bulk density, so producibility is not hindered either. By this means, it is possible to provide a method for producing a lithium-metal composite oxide that enables a lithium-metal composite oxide to be produced at a high yield and, when the lithium-metal composite oxide is used as a positive electrode active material in a nonaqueous electrolyte secondary battery such as a lithium ion secondary battery, enables the nonaqueous electrolyte secondary battery to demonstrate superior charging / discharging capacity.

[0027] Each of the steps in an example of a method for producing coated particles according to the present embodiment will be described in detail below, but steps other than the precursor mixing 241051W001

[0028] 5 and firing steps are not essential, and any steps other than those two steps can be omitted. Furthermore, steps other than those given below may also be included before or after each step given below, provided that the effects of the present disclosure are not compromised as a result.

[0029] Precursor preparation step: a precursor metal compound comprising at least a transition metal is prepared.

[0030] Mixing step: a precursor mixture is obtained by mixing a lithium hydroxide powder and the precursor metal compound.

[0031] Firing step: the precursor mixture prepared in the precursor mixing step is fired.

[0032] Washing step: a lithium-metal composite oxide obtained by firing in a main firing step is subjected to a washing treatment.

[0033] Drying step: the lithium-metal composite oxide that has undergone the washing treatment is dried.

[0034] Addition step: an added compound comprising an added element is added to the lithium-metal composite oxide obtained in either the pre-firing step or the drying step, to obtain a mixture. Heat treatment step: the mixture obtained in the addition step is heat treated to obtain coated particles.

[0035] A precursor metal compound comprising at least a transition metal is first of all prepared. The method for synthesizing the precursor metal compound is not particularly limited, and the following method can be used, for example: an aqueous solution mixture, including an aqueous solution of a transition metal as well as a variety of aqueous solutions of compounds including other elements, depending on the composition of the intended lithium-metal composite oxide, is added drop-wise into a reaction tank in which an aqueous alkaline solution, such as a sodium hydroxide aqueous solution or ammonia solution, is being stirred as the mother liquor, the pH is monitored and controlled to within a suitable range as sodium hydroxide, for example, is also added drop-wise to bring about co-precipitation by means of a wet reaction, and the precursor composite compound is obtained in the form of a hydroxide, or in the form of an oxide or carbonate, for example, obtained by firing the hydroxide.

[0036] It should be noted that, once the alkaline aqueous solution serving as the mother liquor has been prepared for the reaction relating to synthesis of the precursor metal compound, an inert gas, or nitrogen gas which is industrially preferred, is preferably used to set a nitrogen atmosphere inside the reaction tank so that the oxygen concentration inside the reaction tank system and in the solutions is as low as possible. The oxygen concentration can be lowered in order to keep the co-precipitated hydroxide from being oxidized by any oxygen that remains in a given amount or more, and to facilitate the formation of the precursor metal compound via crystallization.

[0037] The transition metal aqueous solution is not particularly limited, but an acidic aqueous solution, 241051W001

[0038] 6 for example, is preferably used, and a sulfuric acid aqueous solution (such as a nickel sulfate aqueous solution, when a nickel compound is used) is even more preferably used. One or more transition metal aqueous solutions can also be used.

[0039] Specific examples of transition metals that can be used include nickel, cobalt, manganese, titanium, niobium, tungsten, molybdenum, vanadium, chromium, iron, yttrium, ruthenium, and tantalum.

[0040] Examples of nickel compounds that can be used include, but are not particularly limited to, one or more selected from among nickel sulfate, nickel oxide, nickel hydroxide, nickel nitrate, nickel carbonate, nickel chloride, nickel iodide, metallic nickel, and the like.

[0041] Examples of cobalt compounds that can be used include, but are not particularly limited to, one or more selected from among cobalt sulfate, cobalt oxide, cobalt hydroxide, cobalt nitrate, cobalt carbonate, cobalt chloride, cobalt iodide, metallic cobalt, and the like.

[0042] Examples of manganese compounds that can be used include, but are not particularly limited to, one or more selected from among manganese sulfate, manganese oxide, manganese hydroxide, manganese nitrate, manganese carbonate, manganese chloride, manganese iodide, metallic manganese, and the like.

[0043] Examples of titanium compounds that can be used include, but are not particularly limited to, one or more selected from among titanyl sulfate, titanium oxide, titanium hydroxide, titanium nitrate, titanium carbonate, titanium chloride, titanium iodide, metallic titanium, and the like.

[0044] Examples of niobium compounds that can be used include, but are not particularly limited to, one or more selected from among niobium oxide, niobium chloride, lithium niobate, niobium iodide, and the like.

[0045] Examples of tungsten compounds that can be used include, but are not particularly limited to, one or more selected from among tungsten oxide, sodium tungstate, ammonium para-tungstate, hexacarbonyl tungsten, tungsten sulfide, and the like.

[0046] Examples of iron compounds that can be used include, but are not particularly limited to, one or more selected from among iron sulfate, iron oxide, iron hydroxide, iron nitrate, iron carbonate, iron chloride, iron iodide, metallic iron, and the like.

[0047] Examples of other transition metals that can be used include one or more selected from among sulfates, oxides, hydroxides, nitrates, carbonates, chlorides, iodides, and metals.

[0048] Elements other than transition metals can also be used in addition to transition metals. 241051W001

[0049] 7

[0050] Examples of elements other than transition metals that can be used include, but are not particularly limited to, magnesium, aluminum, zinc, calcium, gallium, strontium, indium, tin, bismuth, zirconium, boron, and phosphorus.

[0051] Examples of magnesium compounds that can be used include, but are not particularly limited to, one or more selected from among magnesium sulfate, magnesium oxide, magnesium hydroxide, magnesium nitrate, magnesium carbonate, magnesium chloride, magnesium iodide, metallic magnesium, and the like.

[0052] Examples of aluminum compounds that can be used include, but are not particularly limited to, aluminum sulfate, aluminum oxide, aluminum hydroxide, aluminum nitrate, aluminum carbonate, aluminum chloride, aluminum iodide, sodium aluminate, and metallic aluminum.

[0053] Examples of zirconium compounds that can be used include, but are not particularly limited to, one or more selected from among zirconium sulfate, zirconium oxide, zirconium nitrate, ammonium zirconium carbonate, zirconium chloride, zirconium iodide, metallic zirconium, and the like.

[0054] Examples of zinc compounds that can be used include, but are not particularly limited to, one or more selected from zinc sulfate, zinc oxide, zinc hydroxide, zinc nitrate, zinc carbonate, zinc chloride, zinc iodide, and metallic zinc.

[0055] Examples of other elements that can be used include one or more selected from among sulfates, oxides, hydroxides, nitrates, carbonates, chlorides, iodides, and metals.

[0056] The proportions in which the various compounds are blended should be adjusted to ensure that the amounts of the various elements are in the desired proportions in the composition of the intended lithium-metal composite oxide.

[0057] The range of the pH of the liquid in the reaction tank during the synthesis of the precursor metal compound is not particularly limited, but should be determined so as to result in the desired secondary particle size or density, and should range from about 10 to 13, for example.

[0058] The precursor metal compound obtained by means of a wet reaction is preferably washed and then dried after being de-watered.

[0059] Washing the precursor metal compound with water will make it possible to wash out impurities such as sulfate radicals or carbonate radicals and sodium fractions that have been incorporated into aggregated particles or that have become stuck on the surface layer during the reaction. Washing treatments that can be used include procedures in which Nutsche washing is carried 241051W001

[0060] 8 out using a Buchner funnel for small amounts, and procedures in which the suspension after the reaction is pumped to a press filter to be washed with water and de-watered. Pure water, sodium hydroxide aqueous solution, or sodium carbonate aqueous solution, for example, can also be used in the washing treatment, but the use of pure water is preferred for industrial purposes.

[0061] At least the lithium hydroxide powder and the precursor metal compound prepared in the manner described above are mixed in predetermined proportions to prepare the precursor mixture. There is no particular limitation as to the mixing method, but, for example, at least a lithium hydroxide powder compound and the precursor metal compound should both be mixed in a powder state. It should be noted that where other components are used, such components may also be used as solutions or dispersions.

[0062] The lithium hydroxide powder which is used here has, in a particle size range of 1 pm-1000 pm of a particle size distribution obtained by performing dry laser diffraction measurement, a first peak where a peak top frequency value exhibits a maximum value, and a second peak where the peak top frequency value exhibits a maximum value among peaks showing a peak top at particle sizes at least 50 pm away from the particle size showing the peak top of the first peak, a ratio of the peak top frequency value of the second peak to the peak top frequency value of the first peak (peak top frequency value of second peak / peak top frequency value of first peak) is 0.2-0.95, and the loose bulk density is 0.10 g / cm3-0.45 g / cm3.

[0063] Furthermore, in this step, the precursor mixture is adjusted so that the loose bulk density thereof is 0.95 g / cm3or less, and so that a ratio of packing density to loose bulk density (packing density / loose bulk density) is 1.10 or more.

[0064] By using a lithium hydroxide powder and a precursor mixture having such features, it is possible to obtain a lithium-metal composite oxide exhibiting high charging / discharging capacity when used as a positive electrode active material in a lithium ion secondary battery, even if the precursor mixture is packed in a sheath relatively tightly in the firing step which will be described below.

[0065] There is no particular limitation as to the ratio of the peak top frequency value of the second peak to the peak top frequency value of the first peak (peak top frequency value of second peak / peak top frequency value of first peak) in the lithium hydroxide powder, provided that this ratio is 0.2-0.95, and it is preferably 0.25 or more, 0.3 or more, 0.35 or more, or 0.4 or more, for example. Meanwhile, the ratio of the peak top frequency value of the second peak to the peak top frequency value of the first peak is preferably 0.94 or less, 0.93 or less, or 0.92 or less.

[0066] There is no particular limitation as to the loose bulk density of the lithium hydroxide powder 241051W001

[0067] 9 provided that it is 0.10 g / cm3-0.45 g / cm3, and it is preferably 0.12 g / cm3or more, 0.15 g / cm3or more, 0.17 g / cm3or more, 0.20 g / cm3or more, 0.22 g / cm3or more, or 0.25 g / cm3or more, for example. Meanwhile, the loose bulk density of the lithium hydroxide powder is preferably 0.44 g / cm3or less, 0.43 g / cm3or less, or 0.42 g / cm3or less.

[0068] There is no particular limitation as to the loose bulk density of the precursor mixture provided that it is 0.95 g / cm3or less, and it is preferably 0.10 g / cm3or more, 0.20 g / cm3or more, 0.30 g / cm3or more, 0.40 g / cm3or more, 0.50 g / cm3or more, or 0.60 g / cm3or more, for example. Meanwhile, the loose bulk density of the precursor mixture is preferably 0.94 g / cm3or less, 0.93 g / cm3or less, or 0.92 g / cm3or less.

[0069] There is no particular limitation as to the ratio of packing density to loose bulk density of the precursor powder (sheath packing density / loose bulk density), provided that it is 1.10 or more, and it is preferably 1.11 or more, 1.12 or more, or 1.13 or more. Meanwhile, the ratio of the packing density to loose bulk density of the precursor mixture is preferably 1.7 or less, 1.65 or less, 1.60 or less, 1.55 or less, 1.50 or less, 1.45 or less, 1.40 or less, or 1.35 or less.

[0070] There is no particular limitation as to the mixing proportions of the lithium hydroxide powder and the precursor metal compound, but in view of the composition of the target lithium-metal composite oxide, the amount of lithium and the total amount of the other elements should be adjusted, as appropriate, to achieve the desired proportions.

[0071] Moreover, there is no particular limitation as to the lithium hydroxide, and it is possible to use either a lithium hydroxide hydrate such as lithium hydroxide monohydrate (LiOH*H2O) or anhydrous lithium hydroxide (LiOH), but anhydrous lithium hydroxide (LiOH) is preferably used.

[0072] Furthermore, when the lithium hydroxide powder and the precursor metal compound are mixed, a compound of any element may be added in a given proportion and mixed at the same time. The type of element that is added, and the proportions in which it is added, are not particularly limited, but should be adjusted, as appropriate, so as to ensure proportions that are desirable for the intended lithium-metal composite oxide composition.

[0073] The element is not particularly limited, provided that it is an element other than lithium and allows a lithium-metal composite compound to be produced. Specifically, the element can be selected as befits the intended lithium-metal composite oxide composition, where examples of transition metal elements that can be used include nickel, cobalt, manganese, titanium, niobium, tungsten, molybdenum, vanadium, chromium, iron, yttrium, ruthenium, and tantalum, and examples of elements other than transition metals that can be used include magnesium, aluminum, zinc, calcium, gallium, strontium, indium, tin, bismuth, zirconium, boron, and phosphorus. There is no particular limitation as to the state of these elements, and one or more 241051W001

[0074] 10 selected from sulfates, oxides, hydroxides, nitrates, carbonates, chlorides, iodides, and metals may be used.

[0075] The firing step is a step for obtaining a lithium-metal composite oxide by firing the precursor mixture obtained in the precursor mixing step. The firing step may be carried out in two stages comprising a pre-firing step and a main firing step, or may be carried out in only a single stage comprising a main firing step.

[0076] The pre-firing step is a step in which the precursor mixture is fired at a temperature lower than that of the main firing step described below to form a pre-fired material in the form of a lithium- metal composite oxide. Specifically, the precursor mixture is lithiated in the pre-firing step, forming a lithium-metal composite oxide containing at least lithium and a transition metal.

[0077] The main firing step described below is generally carried out by weighing out the lithium hydroxide powder, the precursor metal compound, and compounds of other elements as needed, which are mixed in a mixer, and packing a container such as crucible or sagger with the resulting powder mixture. However, the closer the powder mixture gets to the bottom of the filled container, the more difficult it becomes for the gas that is generated to be evacuated out of the container and for the oxygen to be diffused in the required concentration, particularly in the lithiation reaction. The reaction homogeneity and the primary particle size thus become more difficult to control. Pre-firing is therefore preferably carried out to control the reaction homogeneity and the primary particle size, and is preferably carried out to ensure that the lithiation reaction of the precursor metal compound progresses prior to the main firing.

[0078] A firing method that promotes the lithiation reaction in particular should therefore be incorporated in this pre-firing step. A specific example that may be cited is a method that allows the mixture to be more easily heated, allows the gas that is generated from the lithium compound to be easily discharged, and allows gas having a high oxygen partial pressure to be diffused into the mixture (into the particles). The desired properties can be achieved by, for example, pre-firing less of the mixture.

[0079] To pre-fire the mixture in the pre-firing step, the mixture can be loaded into a sagger or crucible and fired in a static furnace, roller hearth kiln, or pusher furnace, but the mixture is preferably fired while allowed to flow. In this case, a rotary kiln can be used as the apparatus.

[0080] The pre-firing temperature is not particularly limited, but is, for example, preferably 350°C or higher, 360°C or higher, 370°C or higher, 380°C or higher, or 390°C or higher. Meanwhile, the pre-firing temperature is preferably 650°C or lower, 640°C or lower, 630°C or lower, 620°C or lower, or 610°C or lower. 241051W001

[0081] 11

[0082] The length of time for carrying out pre-firing is not particularly limited, provided that it is a period of time ensuring the reliable and homogeneous progress of the lithiation reaction, but it is preferably 1 to 10 hours or 2 to 8 hours, for example.

[0083] The firing temperature in the present disclosure is the maximum temperature when the material being heated is heated. The maximum temperature means the temperature of the part of the material being heated that has the highest temperature. The firing time refers to the time for which the firing temperature is maintained in the prescribed range after reaching that range.

[0084] The atmosphere during pre-firing should be, but is not particularly limited to, an oxidizing atmosphere that ensures the reliable and homogeneous progress of the lithiation reaction. For example, an oxidative decarboxylation gas atmosphere having a carbon dioxide gas concentration of 30 ppm or less, or an oxygen atmosphere having an oxygen concentration of 80 vol% or more, 90 vol% or more, or 95 vol% or more, is preferably used.

[0085] The mixture that has thus been pre-fired is subjected to main firing in a subsequent step to ensure crystal growth or particle growth at a higher temperature.

[0086] A lithium-metal composite oxide obtained by the pre-firing step that becomes aggregated can also be made into powder by using a disc mill or mortar, for example. To ensure a homogeneous reaction in the main firing step, the resulting pre-fired mixture may also be homogenized by being mixed, and additives may be added during the mixing process.

[0087] Crystal growth takes place in the main firing step. The lithium-metal composite oxide thus obtained by the firing step will be in the form of primary particles or secondary particles.

[0088] The main firing temperature is not particularly limited, provided that it is higher than the prefiring temperature, but can be adjusted depending on the composition, for example, of the lithium-metal composite oxide that is to be obtained. For example, the firing temperature is preferably 700°C or higher, 710°C or higher, 720°C or higher, 730°C or higher, 740°C or higher, or 750°C or higher. Meanwhile, the main firing temperature is preferably 1100°C or lower, 1070°C or lower, 1050°C or lower, 1020°C or lower, 1000°C or lower, 970°C or lower, 950°C or lower, 920°C or lower, 900°C or lower, 870°C or lower, 850°C or lower, 820°C or lower, or 800°C or lower. Ensuring that the main firing temperature is within the prescribed range will allow a lithium-metal composite oxide having the desired crystal structure to be obtained. In addition to allowing unreacted components to be minimized, this can also prevent the loss of battery characteristics of non-aqueous electrolyte secondary batteries in which the resulting lithium- metal composite oxide is used in the positive electrode. 241051W001

[0089] 12

[0090] The length of time for which main firing is carried out is not particularly limited, but should be enough time for a composite oxide having the desired crystal structure to be formed. The length of time is, for example, preferably 1 to 15 hours, 2 to 12 hours, or 2 to 10 hours.

[0091] The firing atmosphere is not particularly limited, but preferably has an oxygen partial pressure that will ensure reliable and homogeneous crystal growth, without any reduction of the transition metals included in the pre-fired material during the main firing step. The atmosphere should preferably have a low moisture content or low carbon dioxide gas concentration. For example, an oxidative decarboxylation gas atmosphere having a carbon dioxide gas concentration of 30 ppm or less, or an oxygen atmosphere preferably having an oxygen concentration of 80% by volume or more, 85% by volume or more, 90% by volume or more, or 95% by volume or more, is preferably used.

[0092] There is no particular limitation as to the firing method in the main firing step, but it is possible to pack a sagger or a crucible with the material being fired (the precursor mixture or a pre-fired material that has passed through the pre-firing step), and to fire the material in a static furnace, a roller hearth kiln, or a pusher furnace.

[0093] If the precursor mixture or the pre-fired material obtained in the pre-firing step is fired using a sagger, then there is no particular limitation as to the packing height of the precursor mixture or the pre-fired material obtained in the pre-firing step when the material is packed in the sagger, but it is preferably 100 mm or more, 105 mm or more, 110 mm or more, 115 mm or more, 120 mm or more, 125 mm or more, 130 mm or more, or 135 mm or more. A packing height at or above the required value makes it possible to increase the mass of precursor mixture packed in each sagger, and producibility can be further improved by packing the sagger in a highly compressed manner in relation to the loose bulk density of the precursor mixture. Meanwhile, the packing height is preferably 140 mm or less, 135 mm or less, 130 mm or less, 125 mm or less, 120 mm or less, 115 mm or less, 110 mm or less, or 105 mm or less. If the packing height of the precursor mixture in the sagger is excessively high, then quality may deteriorate due to the difficulty of gas diffusion in the bottom of the sagger and non-uniformity of the reaction in the firing step, and although there may be an increase in the amount of residual LiOH in the lithium- metal composite oxide which is finally obtained or a reduction in battery capacity, it is possible to inhibit a drop in quality with a packing height of no greater than the required value.

[0094] In one embodiment, the lithium-metal composite oxide obtained in the firing step comprises at least lithium and a transition metal, and is in the form of primary particles or secondary particles.

[0095] The chemical composition of the lithium-metal composite oxide is preferably, but not particularly limited to, one that has a layered rock-salt structure and that is represented by the general formula LiaNixCoyMnzMwOa (in the formula, M is one or more elements other than Li, Ni, Co, Mn, 241051W001

[0096] 13 and O; 0.90<a<1.15; x+y+z+w=1.00; and 1.60<a<2.40).

[0097] In the general formula for the lithium-metal composite oxide, the value of a is not particularly limited, provided that it is within the range of 0.90<a<1.2, but it is, for example, preferably 0.905 or more, 0.91 or more, 0.915 or more, 0.92 or more, 0.925 or more, 0.93 or more, 0.935 or more, 0.94 or more, 0.945 or more, 0.95 or more, 0.955 or more, 0.96 or more, 0.965 or more, 0.97 or more, 0.975 or more, 0.98 or more, 0.985 or more, 0.99 or more, 0.995 or more, 1 or more, 1.005 or more, 1.01 or more, 1.015 or more, 1.02 or more, 1.025 or more, 1.03 or more, 1.035 or more, 1.04 or more, 1 .045 or more, 1 .05 or more, 1.055 or more, 1.06 or more, 1.065 or more, 1.07 or more, 1.075 or more, 1.08 or more, 1.085 or more, 1.09 or more, 1 .095 or more, 1.1 or more, 1.105 or more, 1.11 or more, 1.115 or more, 1.12 or more, 1.125 or more, 1.13 or more, 1.135 or more, 1.14 or more, 1.145 or more, 1.15 or more, 1.155 or more, 1.16 or more, 1.165 or more, 1.17 or more, 1 .175 or more, 1.18 or more, 1.185 or more, 1.19 or more, or 1.195 or more. Meanwhile, the value of a is preferably 1.2 or less, 1.195 or less, 1.19 or less, 1.185 or less, 1.18 or less, 1.175 or less, 1.17 or less, 1.165 or less, 1.16 or less, 1.155 or less, 1.15 or less, 1.145 or less, 1.14 or less, 1.135 or less, 1.13 or less, 1.125 or less, 1.12 or less, 1.115 or less, 1.11 or less, 1.105 or less, 1.1 or less, 1.095 or less, 1.09 or less, 1.085 or less, 1.08 or less, 1.075 or less, 1.07 or less, 1.065 or less, 1.06 or less, 1 .055 or less, 1.05 or less, 1.045 or less, 1.04 or less, 1.035 or less, 1.03 or less, 1.025 or less, 1.02 or less, 1.015 or less, 1.01 or less, 1.005 or less, 1 or less, 0.995 or less, 0.99 or less, 0.985 or less, 0.98 or less, 0.975 or less, 0.97 or less, 0.965 or less, 0.96 or less, 0.955 or less, 0.95 or less, 0.945 or less, 0.94 or less, 0.935 or less, 0.93 or less, 0.925 or less, 0.92 or less, 0.915 or less, 0.91 or less, 0.905 or less, or 0.90 or less.

[0098] The value of x in the general formula for the lithium-metal composite oxide is not particularly limited, but is preferably, for example, 0 or more, more than 0, 0.001 or more, 0.0015 or more, 0.002 or more, 0.0025 or more, 0.003 or more, 0.0035 or more, 0.004 or more, 0.0045 or more,

[0099] 0.005 or more, 0.0055 or more, 0.006 or more, 0.0065 or more, 0.007 or more, 0.0075 or more,

[0100] 0.008 or more, 0.0085 or more, 0.009 or more, 0.0095 or more, 0.01 or more, 0.015 or more,

[0101] 0.02 or more, 0.025 or more, 0.03 or more, 0.035 or more, 0.04 or more, 0.045 or more, 0.05 or more, 0.055 or more, 0.06 or more, 0.065 or more, 0.07 or more, 0.075 or more, 0.08 or more, 0.085 or more, 0.09 or more, 0.095 or more, 0.1 or more, 0.105 or more, 0.11 or more, 0.115 or more, 0.12 or more, 0.125 or more, 0.13 or more, 0.135 or more, 0.14 or more, 0.145 or more, 0.15 or more, 0.155 or more, 0.16 or more, 0.165 or more, 0.17 or more, 0.175 or more, 0.18 or more, 0.185 or more, 0.19 or more, 0.195 or more, 0.2 or more, 0.205 or more, 0.21 or more, 0.215 or more, 0.22 or more, 0.225 or more, 0.23 or more, 0.235 or more, 0.24 or more, 0.245 or more, 0.25 or more, 0.255 or more, 0.26 or more, 0.265 or more, 0.27 or more, 0.275 or more, 0.28 or more, 0.285 or more, 0.29 or more, 0.295 or more, 0.3 or more, 0.305 or more, 0.31 or more, 0.315 or more, 0.32 or more, 0.325 or more, 0.33 or more, 0.335 or more, 0.34 or more, 0.345 or more, 0.35 or more, 0.355 or more, 0.36 or more, 0.365 or more, 0.37 or more, 241051W001

[0102] 14

[0103] 0.375 or more, 0.38 or more, 0.385 or more, 0.39 or more, 0.395 or more, 0.4 or more, 0.405 or more, 0.41 or more, 0.415 or more, 0.42 or more, 0.425 or more, 0.43 or more, 0.435 or more, 0.44 or more, 0.445 or more, 0.45 or more, 0.455 or more, 0.46 or more, 0.465 or more, 0.47 or more, 0.475 or more, 0.48 or more, 0.485 or more, 0.49 or more, 0.495 or more, 0.5 or more, 0.505 or more, 0.51 or more, 0.515 or more, 0.52 or more, 0.525 or more, 0.53 or more, 0.535 or more, 0.54 or more, 0.545 or more, 0.55 or more, 0.555 or more, 0.56 or more, 0.565 or more, 0.57 or more, 0.575 or more, 0.58 or more, 0.585 or more, 0.59 or more, 0.595 or more, 0.6 or more, 0.605 or more, 0.61 or more, 0.615 or more, 0.62 or more, 0.625 or more, 0.63 or more, 0.635 or more, 0.64 or more, 0.645 or more, 0.65 or more, 0.655 or more, 0.66 or more, 0.665 or more, 0.67 or more, 0.675 or more, 0.68 or more, 0.685 or more, 0.69 or more, 0.695 or more, 0.7 or more, 0.705 or more, 0.71 or more, 0.715 or more, 0.72 or more, 0.725 or more, 0.73 or more, 0.735 or more, 0.74 or more, 0.745 or more, 0.75 or more, 0.755 or more, 0.76 or more, 0.765 or more, 0.77 or more, 0.775 or more, 0.78 or more, 0.785 or more, 0.79 or more, 0.795 or more, 0.8 or more, 0.805 or more, 0.81 or more, 0.815 or more, 0.82 or more, 0.825 or more, 0.83 or more, 0.835 or more, 0.84 or more, 0.845 or more, 0.85 or more, 0.855 or more, 0.86 or more, 0.865 or more, 0.87 or more, 0.875 or more, 0.88 or more, 0.885 or more, 0.89 or more, 0.895 or more, 0.9 or more, 0.905 or more, 0.91 or more, 0.915 or more, 0.92 or more, 0.925 or more, 0.93 or more, 0.935 or more, 0.94 or more, 0.945 or more, 0.95 or more, 0.955 or more, 0.96 or more, 0.965 or more, 0.97 or more, 0.975 or more, 0.98 or more, 0.985 or more, 0.99 or more, or 0.995 or more. Meanwhile, the value of x is preferably 1 or less, 0.997 or less, 0.995 or less, 0.992 or less, 0.99 or less, 0.987 or less, 0.985 or less, 0.982 or less, 0.98 or less, 0.977 or less, 0. 975 or less, 0.972 or less, 0.97 or less, 0.967 or less, 0.965 or less, 0.962 or less, 0.96 or less, 0.957 or less, 0.955 or less, 0.952 or less, 0.95 or less, 0.947 or less, 0.945 or less, 0.942 or less, 0.94 or less, 0.937 or less, 0.935 or less, 0.932 or less, 0.93 or less, 0.927 or less, 0.925 or less, 0.922 or less, 0.92 or less, 0.917 or less, 0.915 or less, 0.912 or less, 0.91 or less, 0.907 or less, 0.905 or less, 0.902 or less, or 0.9 or less.

[0104] The value of y in the general formula for the lithium-metal composite oxide is not particularly limited, but is preferably, for example, 0 or more, more than 0, 0.001 or more, 0.0015 or more, 0.002 or more, 0.0025 or more, 0.003 or more, 0.0035 or more, 0.004 or more, 0.0045 or more,

[0105] 0.005 or more, 0.0055 or more, 0.006 or more, 0.0065 or more, 0.007 or more, 0.0075 or more,

[0106] 0.008 or more, 0.0085 or more, 0.009 or more, 0.0095 or more, 0.01 or more, 0.015 or more,

[0107] 0.02 or more, 0.025 or more, 0.03 or more, 0.035 or more, 0.04 or more, 0.045 or more, 0.05 or more, 0.055 or more, 0.06 or more, 0.065 or more, 0.07 or more, 0.075 or more, 0.08 or more, 0.085 or more, 0.09 or more, 0.095 or more, 0.1 or more, 0.102 or more, 0.105 or more, 0.107 or more, 0.11 or more, 0.112 or more, 0.115 or more, 0.117 or more, 0.12 or more, 0.122 or more, 0.125 or more, 0.127 or more, 0.13 or more, 0.132 or more, 0.135 or more, 0.137 or more, 0.14 or more, 0.142 or more, 0.145 or more, 0.147 or more, 0.15 or more, 0.152 or more, 0.155 or more, 0.157 or more, 0.16 or more, 0.162 or more, 0.165 or more, 0.167 or more, 0.17 or more, 0.172 or more, 0.175 or more, 0.177 or more, 0.18 or more, 0.182 or more, 0.185 or 241051W001

[0108] 15 more, 0.187 or more, 0.19 or more, 0.192 or more, 0.195 or more, 0.197 or more, 0.2 or more, 0.202 or more, 0.205 or more, 0.207 or more, 0.21 or more, 0.212 or more, 0.215 or more,

[0109] 0.217 or more, 0.22 or more, 0.222 or more, 0.225 or more, 0.227 or more, 0.23 or more, 0.232 or more, 0.235 or more, 0.237 or more, 0.24 or more, 0.242 or more, 0.245 or more, 0.247 or more, 0.25 or more, 0.252 or more, 0.255 or more, 0.257 or more, 0.26 or more, 0.262 or more, 0.265 or more, 0.267 or more, 0.27 or more, 0.272 or more, 0.275 or more, 0.277 or more, 0.28 or more, 0.282 or more, 0.285 or more, 0.287 or more, 0.29 or more, 0.292 or more, 0.295 or more, 0.297 or more, 0.3 or more, 0.302 or more, 0.305 or more, 0.307 or more, 0.31 or more, 0.312 or more, 0.315 or more, 0.317 or more, 0.32 or more, 0.322 or more, 0.325 or more, 0.327 or more, 0.33 or more, 0.332 or more, 0.335 or more, 0.337 or more, 0.34 or more, 0.342 or more, 0.345 or more, 0.347 or more, 0.35 or more, 0.352 or more, 0.355 or more, 0.357 or more, 0.36 or more, 0.362 or more, 0.365 or more, 0.367 or more, 0.37 or more, 0.372 or more,

[0110] 0.375 or more, 0.377 or more, 0.38 or more, 0.382 or more, 0.385 or more, 0.387 or more, 0.39 or more, 0.392 or more, 0.395 or more, 0.397 or more. Meanwhile, the value of y is preferably 0.4 or less, 0.397 or less, 0.395 or less, 0.392 or less, 0.39 or less, 0.387 or less, 0.385 or less, 0.382 or less, 0.38 or less, 0.377 or less, 0.375 or less, 0.372 or less, 0.37 or less, 0.367 or less, 0.365 or less, 0.362 or less, 0.36 or less, 0.357 or less, 0.355 or less, 0.352 or less, 0.35 or less, 0.347 or less, 0.345 or less, 0.342 or less, 0.34 or less, 0.337 or less, 0.335 or less, 0.332 or less, 0.33 or less, 0.327 or less, 0.325 or less, 0.322 or less, 0.32 or less, 0.317 or less, 0.315 or less, 0.312 or less, 0.31 or less, 0.307 or less, 0.305 or less, 0.302 or less, 0.3 or less, 0.297 or less, 0.295 or less, 0.292 or less, 0.29 or less, 0.287 or less, 0.285 or less, 0.282 or less, 0.28 or less, 0.277 or less, 0.275 or less, 0.272 or less, 0.27 or less, 0.267 or less, 0.265 or less, 0.26 or less, 0.257 or less, 0.255 or less, 0.252 or less, 0.25 or less, 0.247 or less, 0.245 or less, 0.242 or less, 0.24 or less, 0.237 or less, 0.235 or less, 0.232 or less, 0.23 or less, 0.227 or less, 0.225 or less, 0.222 or less, 0.22 or less, 0.217 or less, 0.215 or less, 0.212 or less, 0.21 or less, 0.207 or less, 0.205 or less, 0.202 or less, 0.2 or less, 0.197 or less, 0.195 or less, 0.192 or less, 0.19 or less, 0.187 or less, 0.185 or less, 0.182 or less, 0.18 or less, 0.177 or less, 0.175 or less, 0.172 or less, 0.17 or less, 0.167 or less, 0.165 or less, 0.162 or less, 0.16 or less, 0.155 or less, 0.152 or less, 0.15 or less, 0.147 or less, 0.145 or less, 0.142 or less, 0.14 or less, 0.137 or less, 0.135 or less, 0.132 or less, 0.13 or less, 0.127 or less, 0.125 or less, 0.122 or less, 0.12 or less, 0.117 or less, 0.115 or less, 0.112 or less, 0.11 or less, 0.107 or less, 0.105 or less, 0.102 or less, 0.1 or less, 0.095 or less, 0.09 or less, 0.085 or less, 0.08 or less, 0.075 or less, 0.07 or less, 0.065 or less, 0.06 or less, 0.055 or less, 0.05 or less, 0.045 or less, 0.04 or less, 0.035 or less, 0.03 or less, 0.025 or less, 0.02 or less, 0.015 or less, 0.01 or less, 0.0095 or less, 0.009 or less, 0.0085 or less, 0.008 or less, 0.0075 or less, 0.007 or less, 0.0065 or less, 0.006 or less, 0.0055 or less, 0.005 or less, 0.0045 or less, 0.004 or less, 0.0035 or less, 0.003 or less, 0.0025 or less, 0.002 or less, 0.0015 or less, or 0.001 or less.

[0111] The value of z in the general formula for the lithium-metal composite oxide is not particularly 241051W001

[0112] 16 limited, but is preferably, for example, 0 or more, more than 0, 0.001 or more, 0.0015 or more, 0.002 or more, 0.0025 or more, 0.003 or more, 0.0035 or more, 0.004 or more, 0.0045 or more,

[0113] 0.005 or more, 0.0055 or more, 0.006 or more, 0.0065 or more, 0.007 or more, 0.0075 or more,

[0114] 0.008 or more, 0.0085 or more, 0.009 or more, 0.0095 or more, 0.01 or more, 0.015 or more,

[0115] 0.02 or more, 0.025 or more, 0.03 or more, 0.035 or more, 0.04 or more, 0.045 or more, 0.05 or more, 0.055 or more, 0.06 or more, 0.065 or more, 0.07 or more, 0.075 or more, 0.08 or more, 0.085 or more, 0.09 or more, 0.095 or more, 0.1 or more, 0.102 or more, 0.105 or more, 0.107 or more, 0.11 or more, 0.112 or more, 0.115 or more, 0.117 or more, 0.12 or more, 0.122 or more, 0.125 or more, 0.127 or more, 0.13 or more, 0.132 or more, 0.135 or more, 0.137 or more, 0.14 or more, 0.142 or more, 0.145 or more, 0.147 or more, 0.15 or more, 0.152 or more, 0.155 or more, 0.157 or more, 0.16 or more, 0.162 or more, 0.165 or more, 0.167 or more, 0.17 or more, 0.172 or more, 0.175 or more, 0.177 or more, 0.18 or more, 0.182 or more, 0.185 or more, 0.187 or more, 0.19 or more, 0.192 or more, 0.195 or more, 0.197 or more, 0.2 or more, 0.202 or more, 0.205 or more, 0.207 or more, 0.21 or more, 0.212 or more, 0.215 or more, 0.217 or more, 0.22 or more, 0.222 or more, 0.225 or more, 0.227 or more, 0.23 or more, 0.232 or more, 0.235 or more, 0.237 or more, 0.24 or more, 0.242 or more, 0.245 or more, 0.247 or more, 0.25 or more, 0.252 or more, 0.255 or more, 0.257 or more, 0.26 or more, 0.262 or more, 0.265 or more, 0.267 or more, 0.27 or more, 0.272 or more, 0.275 or more, 0.277 or more, 0.28 or more, 0.282 or more, 0.285 or more, 0.287 or more, 0.29 or more, 0.292 or more, 0.295 or more, 0.297 or more, 0.3 or more, 0.302 or more, 0.305 or more, 0.307 or more, 0.31 or more, 0.312 or more, 0.315 or more, 0.317 or more, 0.32 or more, 0.322 or more, 0.325 or more, 0.327 or more, 0.33 or more, 0.332 or more, 0.335 or more, 0.337 or more, 0.34 or more, 0.342 or more, 0.345 or more, 0.347 or more, 0.35 or more, 0.352 or more, 0.355 or more, 0.357 or more, 0.36 or more, 0.362 or more, 0.365 or more, 0.367 or more, 0.37 or more, 0.372 or more, 0.375 or more, 0.377 or more, 0.38 or more, 0.382 or more, 0.385 or more, 0.387 or more, 0.39 or more, 0.392 or more, 0.395 or more, or 0.397 or more. Meanwhile, the value of z is preferably 0.4 or less, 0.397 or less, 0.395 or less, 0.392 or less, 0.39 or less, 0.387 or less, 0.385 or less, 0.382 or less, 0.38 or less, 0.377 or less, 0.375 or less, 0.372 or less, 0.37 or less, 0.367 or less, 0.365 or less, 0.362 or less, 0.36 or less, 0.357 or less, 0.355 or less, 0.352 or less, 0.35 or less, 0.347 or less, 0.345 or less, 0.342 or less, 0.34 or less, 0.337 or less, 0.335 or less, 0.332 or less, 0.33 or less, 0.327 or less, 0.325 or less, 0.322 or less, 0.32 or less, 0.317 or less, 0.315 or less, 0.312 or less, 0.31 or less, 0.307 or less, 0.305 or less, 0.302 or less, 0.3 or less, 0.297 or less, 0.295 or less, 0.292 or less, 0.29 or less, 0.287 or less, 0.285 or less, 0.282 or less, 0.28 or less, 0.277 or less, 0.275 or less, 0.272 or less, 0.27 or less, 0.267 or less, 0.265 or less, 0.26 or less, 0.257 or less, 0.255 or less, 0.252 or less, 0.25 or less, 0.247 or less, 0.245 or less, 0.242 or less, 0.24 or less, 0.237 or less, 0.235 or less, 0.232 or less, 0.23 or less, 0.227 or less, 0.225 or less, 0.222 or less, 0.22 or less, 0.217 or less, 0.215 or less, 0.212 or less, 0.21 or less, 0.207 or less, 0.205 or less, 0.202 or less, 0.2 or less,

[0116] 0.197 or less, 0.195 or less, 0.192 or less, 0.19 or less, 0.187 or less, 0.185 or less, 0.182 or less, 0.18 or less, 0.177 or less, 0.175 or less, 0.172 or less, 0.17 or less, 0.167 or less, 0.165 241051W001

[0117] 17 or less, 0.162 or less, 0.16 or less, 0.155 or less, 0.152 or less, 0.15 or less, 0.147 or less, 0.145 or less, 0.142 or less, 0.14 or less, 0.137 or less, 0.135 or less, 0.132 or less, 0.13 or less, 0.127 or less, 0.125 or less, 0.122 or less, 0.12 or less, 0.117 or less, 0.115 or less, 0.112 or less, 0.11 or less, 0.107 or less, 0.105 or less, 0.102 or less, 0.1 or less, 0.095 or less, 0.09 or less, 0.085 or less, 0.08 or less, 0.075 or less, 0.07 or less, 0.065 or less, 0.06 or less, 0.055 or less, 0.05 or less, 0.045 or less, 0.04 or less, 0.035 or less, 0.03 or less, 0.025 or less, 0.02 or less, 0.015 or less, 0.01 or less, 0.0095 or less, 0.009 or less, 0.0085 or less, 0.008 or less, 0.0075 or less, 0.007 or less, 0.0065 or less, 0.006 or less, 0.0055 or less, 0.005 or less, 0.0045 or less, 0.004 or less, 0.0035 or less, 0.003 or less, 0.0025 or less, 0.002 or less, 0.0015 or less, or 0.001 or less.

[0118] In the general formula for the lithium-metal composite oxide, the value of w is not particularly limited, but is preferably, for example, 0 or more, more than 0, 0.001 or more, 0.0012 or more, 0.0015 or more, 0.0017 or more, 0.002 or more, 0.0022 or more, 0.0025 or more, 0.0027 or more, 0.003 or more, 0.0032 or more, 0.0035 or more, 0.0037 or more, 0.004 or more, 0.0042 or more, 0.0045 or more, 0.0047 or more, 0.005 or more, 0.0052 or more, 0.0055 or more, 0.0057 or more, 0.006 or more, 0.0062 or more, 0.0065 or more, 0.0067 or more, 0.007 or more, 0.0072 or more, 0.0075 or more, 0.0077 or more, 0.008 or more, 0.0082 or more, 0.0085 or more, 0.0087 or more, 0.009 or more, 0.0092 or more, 0.0095 or more, 0.0097 or more, 0.01 or more, 0.012 or more, 0.015 or more, 0.017 or more, 0.02 or more, 0.022 or more, 0.025 or more, 0.027 or more, 0.03 or more, 0.032 or more, 0.035 or more, 0.037 or more, 0.04 or more, 0.042 or more, 0.045 or more, 0.047 or more, 0.05 or more, 0.052 or more, 0.055 or more, 0.057 or more, 0.06 or more, 0.062 or more, 0.065 or more, 0.067 or more, 0.07 or more, 0.072 or more, 0.075 or more, 0.077 or more, 0.08 or more, 0.082 or more, 0.085 or more, 0.087 or more, 0.09 or more, 0.092 or more, 0.095 or more, or 0.097 or more. Meanwhile, the value of w is preferably 0.1 or less, 0.097 or less, 0.095 or less, 0.092 or less, 0.09 or less, 0.087 or less, 0.085 or less, 0.082 or less, 0.08 or less, 0.077 or less, 0.075 or less, 0.072 or less, 0.07 or less, 0.067 or less, 0.065 or less, 0.062 or less, 0.06 or less, 0.057 or less, 0.055 or less, 0.052 or less, 0.05 or less, 0.047 or less, 0.045 or less, 0.042 or less, 0.04 or less, 0.037 or less, 0.035 or less, 0.032 or less, 0.03 or less, 0.027 or less, 0.025 or less, 0.022 or less, 0.02 or less, 0.017 or less, 0.015 or less, 0.012 or less, 0.01 or less, 0.0097 or less, 0.0095 or less, 0.0092 or less, 0.009 or less, 0.0087 or less, 0.0085 or less, 0.0082 or less, 0.008 or less,

[0119] 0.0077 or less, 0.0075 or less, 0.0072 or less, 0.007 or less, 0.0067 or less, 0.0065 or less,

[0120] 0.0062 or less, 0.006 or less, 0.0057 or less, 0.0055 or less, 0.0052 or less, 0.005 or less,

[0121] 0.0047 or less, 0.0045 or less, 0.0042 or less, 0.004 or less, 0.0037 or less, 0.0035 or less,

[0122] 0.0032 or less, 0.003 or less, 0.0027 or less, 0.0025 or less, 0.0022 or less, 0.002 or less,

[0123] 0.0017 or less, 0.0015 or less, 0.0012 or less, or 0.001 or less.

[0124] In the general formula, the element M is not particularly limited, provided that it is one or more elements other than Li, Ni, Mn and O, where examples that can be used include Co, Al, Ti, Mg, 241051W001

[0125] 18

[0126] Zn, Nb, W, Mo, Sb, V, Cr, Ca, Fe, Ga, Sr, Y, Ru, In, Sn, Ta, Bi, Zr, and B. The type of element M should be selected depending on the purpose for which it is being added. When a plurality of elements are used as the element M, the value of w represents the total amount of the plurality of elements.

[0127] The lithium-metal composite oxide obtained in the main firing step may contain impurities, such as unreacted lithium compounds or lithium compounds from the crystal structure that become exposed at the particle surface layer in the course of the pre-firing step and main firing step. When there are large amounts of such lithium compounds, as indicated above, reactions between the lithium hydroxide and binder can result in the gelation of the positive electrode mix paste, leading poor operability in the production process and a deterioration in yield.

[0128] Furthermore, the added compound that is used in the addition step described below will result in the formation of an oxide of lithium and the elements included in the added compound (sometimes referred to below as “added elements”), but the lithium-metal composite oxide may sometimes not be coated. Washing is therefore performed in order to remove or reduce the impurity lithium compounds.

[0129] The solution used in the washing step is not particularly limited; acidic solutions, neutral solutions, or alkaline solutions, for example, can be used, but the use of pure water, which is neutral, is preferred. Depending on the physical properties of the lithium metal compound being washed, a solution adjusted to an alkaline pH can also be used if the use of pure water will result in more Li than necessary being extracted from the particle surface layer.

[0130] The lithium-metal composite oxide obtained in the main firing step is preferably washed in order to produce the coated particles according to the embodiment of the present disclosure in the above manner. On the other hand, over-washing the lithium-metal composite oxide may result in extensive removal of even the lithium contained in the crystal lattice of the lithium-metal composite oxide, which may adversely affect conductivity.

[0131] In cases where process design, for example, precludes cleaning, another option is to increase the amount in which the added compound (to be described later) is added. The added compound will react with any lithium that is not included in the crystal lattice to form a compound, whereby it is possible to inhibit formation of lithium hydroxide and to inhibit gelation of the positive electrode mix when it is formed into a slurry.

[0132] Lithium-metal composite oxides that have been washed in the washing step will contain the water used in the washing step, and should therefore be de-watered and dried in the drying step.

[0133] The specific drying method is not particularly limited. Drying may be effected, for example, in air, 241051W001

[0134] 19 in an oxygen atmosphere, in an oxidative decarboxylation atmosphere having a carbon dioxide concentration of 30 ppm or less, in an inert gas atmosphere such as argon gas, or in a vacuum. Heating also may or may not be effected. The heating temperature is not particularly limited, and may be, for example, 40-200°C, 60-180°C, or 80-160°C.

[0135] In one embodiment, the washing step is followed by a de-watering treatment, where the moisture content of the lithium-metal composite oxide is reduced to no more than 1 mass% using a dryer, for example. This can stave off water-induced conversion of the lithium-metal composite oxide into a rock salt structure and loss of quality.

[0136] The de-watering treatment can be effected via solid-liquid separation of the lithium-metal composite oxide, which is in the form of a slurry after the washing step. Specifically, the solids and liquid should be separated using a filter fabric. Filtration using a press filter and reduced pressure filtration using a Buchner funnel can also be performed.

[0137] The addition step is a step in which an added compound containing an added element is added to a lithium-metal composite oxide to obtain a mixture. The added compound may be added to the lithium-metal composite oxide which is wet prior to the drying step, or may also be added to the lithium-metal composite oxide which has passed through the drying step.

[0138] There is no particular limitation as to the added element which is specifically used here, and it should be selected from transition metals and elements other than transition metals. Examples of transition metals which may be used include: nickel, cobalt, manganese, titanium, niobium, tungsten, molybdenum, vanadium, chromium, iron, yttrium, ruthenium, and tantalum, etc., and examples of elements other than transition metals which may be used include magnesium, aluminum, zinc, calcium, gallium, strontium, indium, tin, bismuth, zirconium, boron, and phosphorus, etc. There is no particular limitation as to the state of these elements, and one or more selected from sulfates, oxides, hydroxides, nitrates, carbonates, chlorides, iodides, and metals may be used.

[0139] In the heat treatment step, the mixture of the lithium-metal composite oxide and the added compound is heat treated, and a coating of the added element is formed on the surface of the lithium-metal composite oxide.

[0140] The heat treatment temperature is not particularly limited, but is, for example, preferably 200°C or higher, 210°C or higher, 220°C or higher, 230°C or higher, 240°C or higher, or 250°C or higher. Meanwhile, the heat treatment temperature is preferably 500°C or lower, 490°C or lower, 480°C or lower, 470°C or lower, 460°C or lower, 450°C or lower, 440°C or lower, 430°C or lower, 420°C or lower, 410°C or lower, or 400°C or lower. 241051W001

[0141] 20

[0142] The length of time of the heat treatment is not particularly limited, but is, for example, preferably 1 to 15 hours, 2 to 12 hours, or 2 to 10 hours.

[0143] Note that the heat treatment temperature in the present disclosure is the maximum temperature when the material being heated is heated. The maximum temperature means the temperature of the part of the material being heated that has the highest temperature. The length of time of the heat treatment refers to the time for which the heat treatment temperature is maintained in the prescribed range after reaching that range.

[0144] EXAMPLES

[0145] The present disclosure will be described in greater detail below using examples, but is not limited to these examples.

[0146] Samples of lithium-metal composite oxides of Examples 1-3 and Comparative Example 1 were prepared in accordance with the method shown below.

[0147] Example 1

[0148] Preparation of precursor compound>

[0149] A nickel sulfate aqueous solution, and cobalt sulfate and sodium aluminate aqueous solutions were mixed to an Ni and Co ratio (molar ratio) of Ni:Co= 89:6 to obtain a metal aqueous solution. Separately from this mixed aqueous solution, a sodium aluminate aqueous solution was prepared so that the amount of Al was AI / (Ni+Co+AI)x100 = 5.0 mol%. 10 L of pure water to which 300 g of a sodium hydroxide aqueous solution and 500 g of aqueous ammonia had been added were prepared in advance as the mother liquor in a reactor, the interior of the reactor was flushed with nitrogen gas at a flow rate of 0.7 L / min to create a nitrogen atmosphere, and the reaction was also carried out under a nitrogen atmosphere. The interior of the reactor was purged with nitrogen gas, and this was also maintained during the reaction.

[0150] After this, the mixed aqueous solution, sodium aluminate aqueous solution, sodium hydroxide aqueous solution and ammonia water were simultaneously dripped at a predetermined rate while a stirring blade was rotated at 1000 rpm, and, by means of a wet reaction in which the dripping amount of alkaline solution was adjusted to achieve a pH of 12.1 , the Ni, Co and Al were reacted so as to crystallize and form particle aggregates, whereby the Ni, Co and Al coprecipitated so as to crystallize and form particle aggregates, and a coprecipitate was obtained.

[0151] After this, the slurry inside the reactor was subjected to solid-liquid separation and further washed with pure water to thereby reduce residual impurities, after which the coprecipitate in a caked state was dried for 12 hours at 100°C under the atmosphere to obtain a precursor metal compound. 241051W001

[0152] 21

[0153] Preparation of lithium hydroxide powder>

[0154] Lithium hydroxide hydrate was de-watered in a vacuum dryer by reducing the pressure of the atmosphere from atmospheric pressure to -50 Pa and performing vacuum drying for 5 hours at 150°C. Here, the loose bulk density of the resulting anhydrous lithium hydroxide was 0.57 g / cm3.

[0155] The resulting anhydrous lithium hydroxide was ground under the following conditions using a jet mill (PJM-280SP, manufactured by Nippon Pneumatic Mfg. Co., Ltd.).

[0156] <Operating conditions of jet mill>

[0157] • Feed rate: 100 Kg / hour

[0158] • Grinding pressure: 0.25 MPa

[0159] The resulting lithium hydroxide powder had a loose bulk density of 0.25 g / cm3, the particle size at the peak top of the maximum peak in accordance with volume-based particle size distribution measurement in dry laser diffraction particle size distribution measurement (Seishin Enterprise) was 7.4 pm, the particle size at the peak top of the second highest peak (second peak top) was 122.2 pm, and the ratio of peak top frequency in the maximum peak and the second peak was 0.43.

[0160] Production of Lithium-Metal Composite Oxide>

[0161] The precursor compound and lithium hydroxide powder obtained in this way were weighed out so that the ratio (molar ratio) of the total amount of Li and Ni, Co and Al were Li / (Ni+Co+AI)=1.035, and the materials were mixed using a mixer to prepare a precursor mixture. The loose bulk density of the mixture was measured using a powder tester (manufactured by Hosokawa Micron).

[0162] Saggers of length x width x height of 320 mm x 320 mm x 150 mm were then packed for 20 seconds per sagger with the precursor mixture using a packer, degassing was performed until the degassing pressure reached -0.002 MPa, the packing height was confirmed as 130-140 mm, and the density at this time was taken as the sheath packing density.

[0163] The mixture was then fired over a 5-hour period at a maximum temperature of 740°C in an oxygen atmosphere (oxygen concentration: 97 vol%) using an electric furnace, cooled and then ground using a grinding mill. A lithium-metal composite oxide was obtained. The amount of residual LiOH in the resulting lithium-metal composite oxide according to the Warder method was approximately 1.18 mass%.

[0164] The resulting lithium-metal composite oxide was introduced into pure water (water temperature: 241051W001

[0165] 22

[0166] 25°C) in a reaction tank (10 L capacity), and the contents were stirred over a 10-minute period to prepare a slurry. Here, the ratio of the amount of the lithium-metal composite oxide relative to the amount of pure water (solid-liquid ratio) was adjusted to 1500g / L. The resulting slurry was filtered using a Buchner funnel to obtain lithium-metal composite oxide cake. The cake had a moisture content of 5.3 wt%.

[0167] Tungsten oxide (WO3) powder was admixed with the resulting cake so that W / (Ni + Co + Al) x100 = 0.5 mol%, after which a heat treatment was performed over a 60-minute period at 100°C using a vacuum drying apparatus, and the cake was dried. After cooling, a lithium-metal composite oxide sample was obtained by grinding the cake in a grinding mill.

[0168] Example 2

[0169] A lithium-metal composite oxide sample was obtained in the same way as in Example 1, except that anhydrous lithium hydroxide prepared under the same conditions as in Example 1 was ground under the following conditions using a Masscolloider (manufactured by Masuko Sangyo Co., Ltd.) (Masscolloider operating conditions)

[0170] • Grinder size: 300 mm diameter

[0171] • Feed rate: 200 kg / hr

[0172] • Clearance between upper and lower grinders: 350 pm

[0173] • Rotation speed during processing: 1500 rpm

[0174] Moreover, the resulting lithium hydroxide powder had a loose bulk density of 0.30 g / cm3, the particle size at the peak top of the maximum peak in accordance with a volume-based particle size distribution in dry laser diffraction particle size distribution measurement (Seishin Enterprise) was 7.4 pm, the particle size at the peak top of the second highest peak (second peak top) was 332.5 pm, and the ratio of peak top frequency in the maximum peak and the second peak was 0.65.

[0175] Example 3

[0176] A lithium-metal composite oxide sample was obtained in the same way as in Example 1, except that anhydrous lithium hydroxide powder prepared under the same conditions as in Example 1 was ground under the following conditions using a Masscolloider (manufactured by Masuko Sangyo Co., Ltd.) (Masscolloider operating conditions)

[0177] • Grinder size: 300 mm diameter

[0178] • Feed rate: 200 kg / hr

[0179] • Clearance between upper and lower grinders: 580 pm

[0180] • Rotation speed during processing: 1500 rpm 241051W001

[0181] 23

[0182] Moreover, the resulting lithium hydroxide powder had a loose bulk density of 0.42 g / cm3, the particle size at the peak top of the maximum peak in accordance with a volume-based particle size distribution in dry laser diffraction particle size distribution measurement (Seishin Enterprise) was 406.2 pm, the particle size at the peak top of the second highest peak (second peak top) was 7.4 pm, and the ratio of peak top frequency in the maximum peak and the second peak was 0.91.

[0183] Comparative Example 1

[0184] A lithium-metal composite oxide sample was obtained in the same way as in Example 1, except that anhydrous lithium hydroxide prepared under the same conditions as in Example 1 was ground under the following conditions using a Masscolloider (manufactured by Masuko Sangyo Co., Ltd.) (Masscolloider operating conditions)

[0185] • Grinder size: 300 mm diameter

[0186] • Feed rate: 200 kg / hr

[0187] • Clearance between upper and lower grinders: 800 pm

[0188] • Rotation speed during processing: 1500 rpm

[0189] Moreover, the resulting lithium hydroxide powder had a loose bulk density of 0.49 g / cm3, the particle size at the peak top of the maximum peak in accordance with a volume-based particle size distribution in dry laser diffraction particle size distribution measurement (Seishin Enterprise) was 406.2 pm, the particle size at the peak top of the second highest peak (second peak top) was 7.4 pm, and the ratio of peak top frequency in the maximum peak and the second peak was 0.81.

[0190] Samples of Examples 1-3 and Comparative Example 1 were evaluated by the methods given below. The examples are shown along with the results.

[0191] Composition of Precursor Compounds and Lithium-Metal Composite Oxide Samples: Samples of 0.2 g of precursor compounds or lithium-metal composite oxides were heated and dissolved in 25 mL of 20% hydrochloric acid solution, the solutions were cooled and then transferred to 100 mL measuring flasks, and pure water was introduced to prepare adjusted solutions. The constituent elements of the solutions that had been prepared were quantified using an ICP-AES [Optima 8300, manufactured by PerkinElmer Co., Ltd.], confirming that the proportions of the metals in the precursor compounds and lithium-metal composite oxides were as prescribed.

[0192] Measurement of Loose Bulk Density>

[0193] The loose bulk density of the anhydrous lithium hydroxide powders and the precursor mixtures was measured using a powder tester in accordance with JIS Z 8804-2:2002 “Methods for measuring physical properties of powders - Section 2: Bulk density test”. 241051W001

[0194] 24

[0195] <Dry Laser Particle Size Distribution Measurement

[0196] Dry laser particle size distribution measurements were carried out using a laser particle size distribution measurement apparatus (LMS-2000e, Seishin Enterprise Co., Ltd.) with air as a dispersion medium and an air pressure of 4 bar. A volume-based particle size distribution was obtained from the measurement results.

[0197] The measurements were performed 8 times, and the results of measurements for which the particle size distribution chart clearly differs as follows were excluded.

[0198] (1) Measurement results in which the magnitude relationship between peak top values of two or more peaks is different

[0199] (2) Measurement results having a peak at 1000 pm or more

[0200] (3) Measurement results having four or more peaks

[0201] In the remaining measurement results, the particle size in a range of 1 pm-1000 pm at the peak top having the maximum peak was calculated as a particle size corresponding to the peak top of a first peak (also referred to below as the “first peak top particle size”), and the particle size at the peak top having the next largest peak was calculated as a particle size corresponding to the peak top of a second peak (also referred to below as the “second peak top particle size”), and the average value of the particle sizes at those peaks was used.

[0202] Furthermore, a ratio (second peak / first peak) of the frequency value of the particle size at the second peak top (also referred to below as the “second peak top frequency (%)”) to the frequency value of the particle size at the first peak top (also referred to below as the “first peak top frequency (%)”) was calculated.

[0203] Measurement of Moisture Content>

[0204] The moisture content (ppm) of the samples was determined as the amount of moisture that had been produced up to 300°C based on the Karl Fischer method (coulometric titration).

[0205] Measurement of Amount of Residual Lithium Hydroxide>

[0206] The amount of residual lithium hydroxide in samples was measured and calculated based on the Warder method during neutralizing titration. Specifically, the amount was determined by adding 20 g of a particle powder sample to 100 mL of water, stirring the contents for 20 minutes at room temperature, filtering off the solids, and titrating the resulting supernatant using 0.2 N hydrochloric acid. Two points where the gradient was greatest on a pH curve drawn by plotting the titrated amount (mL) on the horizontal axis and supernatant pH on the vertical axis were used as the first titration point and second titration point, starting from the point where the titrated amount was smaller, and the amount of residual lithium was the value obtained from the titrated amounts at these points, as calculated using a calculation formula.

[0207] <Nonaqueous Electrolyte Secondary Battery Characteristics> 241051W001

[0208] 25

[0209] Production of Coin Cells Using Positive Electrode Active Material: 2032-type coin cells employing the lithium-metal composite oxide as the positive electrode active material were produced by using a positive electrode, negative electrode and electrolytic solution produced by the following methods.

[0210] Using acetylene black and graphite as the conductive agent at a weight ratio of acetylene black:graphite=1 :1 , and using polyvinylidene fluoride as the binder, the sample serving as a positive electrode active material, a conductive agent and a binder were blended to achieve a weight ratio of positive electrode active materiakconductive agent:binder=90:6:4, and a slurry obtained by mixing these materials with N-methylpyrrolidone was coated on an aluminum foil. The coated aluminum foil was dried at 110°C to prepare a sheet, which was punched to a diameter of 15 mm and then rolled to a composite material density of 3.0 g / cm3for use as the positive electrode.

[0211] Lithium foil having a thickness of 500 pm punched to a diameter of 16 mm was used as the negative electrode.

[0212] An ethylene carbonate (EC) and dimethyl carbonate (DMC) solvent mixture prepared to an EC:DMC volume ratio of 1 :2 was prepared, and a solution obtained by mixing 1 M LiPF6(electrolyte) with the solvent mixture was used as the electrolytic solution.

[0213] Coin cells produced by the method above were charged (constant current) at a current density of 0.1 C to 4.30 V (upper limit voltage) at 25°C, and were then charged at a constant voltage to a current of 0.01 C. The capacity at this time was used as the initial charging capacity (mAh / g).

[0214] After a 5-minute pause, constant current discharging was then performed at a constant current density of 0.1 C to 3.00 V under the same conditions, and the initial discharging capacity (mAh / g) was determined after a 5-minute pause.

[0215] The initial charging / discharging efficiency was calculated on the basis of the following equation using the measured value of the initial charging capacity and the measured value of the initial discharging capacity.

[0216] Initial charging / discharging efficiency (%) = (initial discharging capacity / initial charging capacity) x 100

[0217] The results of the tests described above are shown in Table 1.

Claims

241051W00127CLAIMS1. A method for producing a lithium-metal composite oxide, the method comprising: a precursor mixing step in which a precursor mixture is obtained by mixing a lithium hydroxide powder and a precursor metal compound comprising at least a transition metal; and a firing step in which a lithium-metal composite oxide is obtained by firing the precursor mixture, wherein, in the precursor mixing step, the lithium hydroxide powder which is used has, in a particle size range of 1 pm-1000 pm of a particle size distribution obtained by performing dry laser diffraction measurement, a first peak where a peak top frequency value exhibits a maximum value, and a second peak where the peak top frequency value exhibits a maximum value among peaks showing a peak top at particle sizes at least 50 pm away from the particle size showing the peak top of the first peak, a ratio of the peak top frequency value of the second peak to the peak top frequency value of the first peak (peak top frequency value of second peak / peak top frequency value of first peak) is 0.2-0.95, and the loose bulk density is 0.10 g / cm3-0.45 g / cm3, and the precursor mixture is adjusted so that the loose bulk density thereof is 0.95 g / cm3or less, and so that a ratio of packing density to loose bulk density (sheath packing density / loose bulk density) is 1.10 or more.

2. The method for producing a lithium-metal composite oxide as claimed in claim 1, wherein the lithium-metal composite oxide is represented by the general formula LiaNixCoyMnzMwOa (in the formula, M is one or more elements other than Li, Ni, Co, Mn and O; 0.90<a<1.15; x+y+z+w=1.00; and 1.60<a<2.40).

3. A lithium hydroxide powder having, in a particle size range of 1 pm-1000 pm of a particle size distribution obtained by performing dry laser diffraction measurement, a first peak where a peak top frequency value exhibits a maximum value, and a second peak where the peak top frequency value exhibits a maximum value among peaks showing a peak top at particle sizes at least 50 pm away from the particle size showing the peak top of the first peak, a ratio of the peak top frequency value of the second peak to the peak top frequency value of the first peak (peak top frequency value of second peak / peak top frequency value of first peak) is 0.2-0.95, and the loose bulk density is 0.10 g / cm3-0.45 g / cm3.

4. The lithium hydroxide powder as claimed in claim 3, for use as a starting material for the production of a lithium-metal composite oxide.

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