JPH09326255A - Manufacture of positive electrode active material and nonaqueous secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture positive electrode active material nickel acid lithium having a stable charging-discharging characteristic with excellent productivity, and provide a lithium ion battery with an excellent charging-discharging characteristic by manufacturing nickel acid lithium from a lithium compound and nickel compound by a prescribed process. SOLUTION: First of all, positive electrode active material nickel acid lithium is manufactured by mixing a melt obtained by a lithium compound or a nickel compound melting at a temperature not higher than 300 deg.C and a nickel compound or a lithium compound unmelting at a temperature not higher than 300 deg.C. Next, an obtained mixture is cooled or pulverized after cooling, and baked at a 700 to 950 deg.C in the air or in an oxygen atmosphere where a volume rate of oxygen is increased more than in the air. In a lithium ion battery using positive electrode active material nickel acid lithium manufactured in such a process, a positive electrode 14 and a negative electrode 16 are arranged and wound so as to oppose each other by sandwiching a separator 18.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a positive electrode active material and a non-aqueous secondary battery. More specifically, the present invention includes a method for producing a positive electrode active material made of LiNiO ₂ , a positive electrode containing the positive electrode active material, a lithium-containing material, or a material capable of inserting / removing lithium, particularly carbon or graphite. The present invention relates to a non-aqueous secondary battery including a negative electrode and a non-aqueous ionic conductor.

[0002]

2. Description of the Related Art With the miniaturization and power saving of electronic devices,
Research and development of a secondary battery that is lightweight and uses an alkali metal such as lithium capable of discharging a high voltage is in progress. When an alkali metal such as lithium is used alone for the negative electrode, dendrites (dendritic crystals) are generated and grow on the metal dissolution-precipitation surface due to repeated charge / discharge, that is, the dissolution-precipitation process of the alkali metal. This dendrite causes a short circuit inside the battery by penetrating the separator and coming into contact with the positive electrode. It was found that when an alkali metal alloy was used in the negative electrode for a secondary battery instead of an alkali metal, the generation of dendrite was suppressed and the charge / discharge cycle characteristics were improved as compared with the case of using a metal alone. But,
The use of the alloy does not completely prevent dendrites from being generated, and a short circuit inside the battery may occur in the same manner as described above.

In recent years, instead of using a dissolution-precipitation process or a dissolution-precipitation-diffusion process in a solid for a negative electrode, an absorption-desorption process of alkali metal ions is used. It has been reported to use organic materials such as carbon and conductive polymers. As a result, the generation of dendrites that occurred when an alkali metal or its alloy was used did not occur in principle, and the problem of short circuit inside the battery was drastically reduced. Therefore, at present, lithium ion batteries using carbon or graphite for the negative electrode and lithium cobalt oxide for the positive electrode have been put into practical use.

However, when lithium cobalt oxide is used for the positive electrode, there is a problem that the amount of cobalt is scarce and the cost of the raw material becomes high. Therefore, lithium nickel oxide (LiNiO ₂ ) using nickel, which is lower in cost and richer in resources, has been attracting attention since it was proposed by John Bannister Goodenaf et al. (Japanese Patent Publication No. 63-59507).

There are the following methods for producing lithium nickel oxide (LiNiO ₂ ). Method for firing anhydrous lithium hydroxide and metallic nickel in an oxygen atmosphere (J. Am. Chem. Soc., 76, 1499 (195
4)), LiOH.H ₂ O and NiO are mixed, fired at 600 ° C. in an air atmosphere, pulverized, and fired again at a temperature of 600 to 800 ° C. to obtain Li _y Ni _2-y O ₂ . Method (JP-A-2-40861), LiMO ₂ (where M is Co, Ni, and 600 to 800 ° C. (preferably 800 ° C., 6 hours of treatment is performed twice)).
Method for obtaining one or more elements selected from Fe and Mn (JP-A-4-181660), lithium peroxide (Li ₂ O ₂ ) and nickel oxide (Ni)
O) is mixed and reacted at a temperature of 750 ° C. or lower, and then rapidly cooled from that temperature (Japanese Patent Laid-Open No. 20574/1993).
No. 1), lithium nitrate, and at least one of nickel hydroxide and nickel oxyhydroxide, and firing at a temperature of 500 to 1000 ° C. (JP-A-5-2510).
No. 79) is known.

However, in the above method in which the compound of the lithium source and the compound of the nickel source are mixed in a solid state and then calcined,
There is a problem that the mixed state of nickel and lithium is not uniform before firing. Alternatively, nickel acetate and lithium acetate are heated and dissolved in ethylene glycol. Then, the heated and solidified material is mixed with 400
C., heat treated in air, pulverized, and fired at 700.degree. C. in an oxygen stream. Furthermore, there is a method of firing at 800 ° C. in an oxygen stream (JP-A-6-203834). However, this method is complicated in reaction time and manufacturing process.

In view of the above problems, there has been proposed a method for easily producing nickel lithium oxide by uniformly mixing. That is, (1) 60 mol of a 4.5 mol / l lithium hydroxide aqueous solution and a 1.0 mol / l nickel nitrate aqueous solution are used.
Mix equimolar at ℃ and stir it. Then, the substance obtained by drying under reduced pressure is pulverized, pre-baked at 300 ° C., and then main-baked at 800 ° C. (Chemistry Express, 6,
161 (1991)), (2) nickel salt and lithium salt, and optionally cobalt salt dissolved in a solvent, wet-mixed, and then heated and baked to obtain LiCo _x Ni _1-x O ₂ (0 ≦ x ≦ 0.
Method (5) (JP-A-5-325966), (3)
A water-soluble nickel salt and a water-soluble lithium salt are mixed in an aqueous solution, and the cake-like substance dried and solidified is heated to 600 to 800 ° C.
There is known a method such as a method of firing at the temperature (Japanese Patent Laid-Open No. 6-44970). These are methods in which an aqueous solution is mixed, dried and fired.

[0008] Further, in view of a macroscopic view, in order to uniformly mix, a cake-like substance obtained by stirring and kneading an aqueous solution of a nickel compound powder which is hardly soluble or insoluble in water and an aqueous solution of a lithium salt is dried and solidified. A method of baking at a temperature of 600 to 800 ° C. (JP-A-6-44971), a lithium source and a nickel source are weighed so that the molar ratio of lithium and nickel is 1: 1 and a small amount of water is added as a dispersant. There is also known a method of thoroughly mixing, drying and firing at 650 ° C. in the atmosphere (JP-A-6-96769).

[0009]

In a method for producing a positive electrode active material LiNiO ₂ for a non-aqueous secondary battery, in a method of mixing a lithium source compound and a nickel source compound in a solid and then firing the mixture, nickel before firing and nickel before firing are used. There is a problem that the mixed state of lithium is not uniform. Further, in the method of mixing using an aqueous solution, drying and firing, the mixed state of nickel and lithium is improved by dissolving the nickel source and / or the lithium source in water, as compared with the mixing of solids. However, there is a problem that they are not mixed uniformly.

Further, a method in which nickel acetate and lithium acetate are heated and dissolved in ethylene glycol, the substance which is heated and solidified is heat-treated in air, pulverized, fired in an oxygen stream, and further fired in an oxygen stream is used. is there. However, this method has a problem that the reaction time and the manufacturing process are complicated. Further, it is attempted to obtain a more uniform mixture by a method of stirring and kneading an aqueous solution of a slightly soluble or insoluble nickel compound powder and a water-soluble lithium salt, and drying and solidifying the mixture, or by using water as a dispersion medium. However, there is a problem that when water is removed as a solvent or a dispersion medium, it is not uniformly mixed.

[0011]

In order to solve these problems, the inventors of the present invention have earnestly studied, and as a result, 3
It was found that a lithium compound and a nickel compound that melt at a temperature of 00 ° C or lower and a nickel compound or a lithium compound that does not melt at a temperature of 300 ° C or lower are stirred or kneaded as described below to uniformly mix the lithium compound and the nickel compound. The present invention has been completed.

Thus, according to the present invention, a melt obtained by melting a lithium compound that melts at a temperature of 300 ° C. or lower or a nickel compound that melts at a temperature of 300 ° C. or lower does not melt at a temperature of 300 ° C. or lower. After mixing with a nickel compound or a lithium compound that does not melt at a temperature of 300 ° C. or lower, the obtained mixture is cooled or crushed after cooling, and at a temperature of 700 to 950 ° C. and in air or in air, a volume ratio of oxygen. Under a high oxygen atmosphere (main firing), lithium nickel oxide (LiN
A method for producing a positive electrode active material is provided, which comprises producing iO ₂ ).

Further, according to the present invention, a lithium compound or a nickel compound, which melts at a temperature of 300 ° C. or lower, and
A nickel compound or a lithium compound that does not melt at a temperature of 0 ° C or lower is mixed, and this is melted at a temperature of 300 ° C or lower, stirred and kneaded, and the obtained mixture is cooled or crushed after cooling, and 700 to 950 ° C. Lithium Nickelate (LiNiO ₂ ) which is a positive electrode active material after being fired in the air at an ambient temperature
A method for producing a positive electrode active material, comprising:

According to the present invention, a lithium compound that melts at a temperature of 300 ° C. or lower, a nickel compound that melts at a temperature of 300 ° C. or lower, and a nickel compound that does not melt at a temperature of 300 ° C. or lower or a temperature of 300 ° C. or lower. Lithium compounds that do not melt at 3 and transition metal compounds or 3B, 4
LiNi, which is a positive electrode active material, is prepared by using a compound containing a Group B or 5B element, cooling, or crushing after cooling, and then performing main firing in air or an oxygen atmosphere in which the volume ratio of oxygen is higher than that of air.
_1-x M _x O ₂ (0 <x <0.5, M is a transition metal or 3
B, 4B, and 5B elements) are provided. Further, according to the present invention, the LiNi _1-x M _x O produced by the above production method is used.
₂ (0 ≦ x <0.5, M is a transition metal or 3B, 4B, 5
Provided is a non-aqueous secondary battery having a positive electrode containing a positive electrode active material composed of a group B element), a negative electrode, and an ionic conductor.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION First, 300 used in the present invention.
Examples of the lithium compound that melts at a temperature of ℃ or less include lithium nitrate / anhydride or trihydrate, lithium acetate / dihydrate, lithium iodide / trihydrate, lithium hydrogen sulfate, lithium hydrogen phosphate and the like. Can be mentioned. Of these, lithium nitrate / anhydrate or trihydrate, lithium acetate / dihydrate, lithium iodide /
Trihydrate is preferred.

Examples of nickel compounds that melt at a temperature of 300 ° C. or lower include nickel nitrate hexahydrate and nickel perchlorate hexahydrate. Of these, nickel nitrate hexahydrate is preferable from the viewpoint of safety. Nickel compounds that do not melt at temperatures below 300 ° C include nickel oxide, nickel hydroxide, nickel oxyhydroxide, nickel carbonate, basic nickel carbonate hydrate, nickel acetate tetrahydrate, nickel oxalate dihydrate. Japanese product, nickel formate
Examples thereof include dihydrate, nickel chloride / anhydrous or hexahydrate, nickel bromide, nickel iodide, nickel sulfide, nickel sulfate and the like. Of these, nickel oxide, nickel hydroxide, nickel oxyhydroxide, nickel carbonate, basic nickel carbonate hydrate, nickel acetate tetrahydrate, nickel oxalate dihydrate, which hardly remain as impurities after main firing , Nickel formate dihydrate, nickel chloride anhydrous or hexahydrate.

Examples of the lithium compound which does not melt at a temperature of 300 ° C. or lower include lithium hydroxide / anhydride or monohydrate, lithium oxide, lithium carbonate, lithium oxalate, lithium chloride, lithium bromide / anhydride or monohydrate. Compounds, lithium iodide / anhydride, lithium acetate / anhydride, lithium sulfide, lithium sulfate, lithium nitride and the like. Of these, lithium hydroxide / anhydride or monohydrate, which does not easily remain as an impurity after the main calcination and is highly safe, lithium oxide, lithium carbonate, lithium oxalate, lithium chloride, lithium bromide / anhydride or 1 water. Sulfate, lithium iodide / anhydride, and lithium acetate / anhydride are preferable.

Further, in order to simplify the cost and the manufacturing apparatus, it is preferable to use a nickel compound that melts at a low temperature of 130 ° C. or lower and a lithium compound that does not melt at a temperature of 130 ° C. or lower. Examples of such nickel compounds include nickel nitrate hexahydrate, and examples of lithium compounds include lithium nitrate anhydride or trihydrate, lithium hydroxide anhydride or monohydrate, lithium oxide, lithium carbonate. , Lithium oxalate, lithium chloride, lithium bromide / anhydride or monohydrate, lithium iodide / anhydride, lithium acetate / anhydride.

A transition metal compound or a compound containing a group 3B, 4B or 5B element (hereinafter referred to as a third component compound) is
Ti, V, Cr, Mn, Fe, Co, Cu, Zn, Y,
Zr, Nb, Mo, La, W, Al, In, Sn, P
Compounds containing b, Sb and Bi are preferable from the viewpoint of improving battery performance. Specifically, titanium chloride, titanium bromide, titanium iodide, titanium oxide, titanium oxychloride, titanium hydroxide, titanium nitrate, vanadium chloride, vanadium bromide, vanadium iodide, vanadium oxide, vanadium oxychloride, oxyodor. Vanadium iodide, vanadium acetate,
Vanadyl oxalate, chromium chloride, chromium trioxide, chromium nitrate, chromium acetate, chromium oxalate, manganese chloride, manganese bromide, manganese iodide, manganese oxide, manganese hydroxide, manganese nitrate, manganese carbonate, manganese acetate, manganese oxalate, chloride Iron, iron bromide, iron iodide, iron oxide, iron sulfate, iron nitrate, iron carbonate, iron acetate, iron oxalate, cobalt chloride cobalt bromide, cobalt iodide, cobalt oxide, cobalt hydroxide, cobalt sulfate, cobalt nitrate , Cobalt carbonate,
Cobalt acetate, cobalt oxalate, copper chloride, copper bromide, copper iodide, copper oxide, copper hydroxide, copper sulfate, copper nitrate, copper carbonate, copper acetate, copper oxalate, zinc chloride, zinc bromide, zinc iodide, Zinc oxide, zinc hydroxide, zinc sulfate, zinc nitrate, zinc carbonate, zinc acetate, zinc oxyacetate, zinc oxalate, yttrium chloride,
Yttrium bromide, yttrium iodide, yttrium oxide, yttrium hydroxide, yttrium sulfate, yttrium nitrate, yttrium carbonate, yttrium acetate, yttrium oxalate, zirconium chloride, zirconium bromide, zirconium iodide, zirconium oxide, zirconium oxychloride, zirconium sulfate , Zirconium nitrate, zirconium acetate, niobium chloride, niobium bromide, niobium oxychloride, niobium oxide, niobium hydrogen oxalate, molybdenum chloride, molybdenum bromide, molybdenum iodide, molybdenum oxychloride, molybdenum oxide, molybdenum hydroxide, molybdenum acetate, Lanthanum chloride, lanthanum bromide, lanthanum iodide, lanthanum oxide, lanthanum hydroxide, lanthanum sulfate, lanthanum nitrate, lanthanum carbonate, lanthanum acetate, lanthanum oxalate, tangs chloride Emissions, tungsten bromide, iodide tungsten, tungsten oxychloride, oxybromide tungsten, tungsten oxide, aluminum chloride,
Aluminum bromide, aluminum iodide, aluminum oxide, aluminum hydroxide, aluminum nitrate, aluminum acetate, aluminum oxalate, indium chloride, indium bromide, indium iodide, indium oxide, indium hydroxide, indium sulfate, indium nitrate, tin chloride , Tin bromide, tin iodide, tin oxide, tin hydroxide, tin sulfate, tin acetate, tin oxalate, lead chloride, lead bromide, lead iodide, lead oxide, lead oxyhydroxide, lead nitrate, lead carbonate, Lead hydroxide, lead acetate, lead oxalate, antimony chloride, antimony bromide, antimony iodide, antimony oxide, antimony sulfate, bismuth chloride,
Examples thereof include bismuth bromide, bismuth iodide, bismuth oxide, bismuth sulfate, bismuth nitrate, bismuth carbonate oxide, bismuth acetate and bismuth oxalate. When a lithium compound is selected as a compound that melts at a temperature of 300 ° C. or lower, a nickel compound is selected as a compound that does not melt at a temperature of 300 ° C. or lower. On the other hand, when a nickel compound is selected as the compound that melts at a temperature of 300 ° C. or lower,
A lithium compound is selected as a compound that does not melt at a temperature of 0 ° C. or lower. The lithium compound and the nickel compound have a molar ratio of nickel and lithium of 1: 0.8 or more (L
Weigh so that the i / Ni ratio is 0.8 or more). Preferably, the ratio is 1: 0.8 to 1: 1.3 (Li / Ni ratio is 0.1.
8 to 1.3), more preferably 1: 1.0 to 1: 1.3.
(Li / Ni ratio is 1.0 to 1.3) is preferable. When the molar ratio of nickel and lithium (Li / Ni ratio) is less than 0.8, lithium nickel oxide crystals do not develop during firing, and the discharge capacity decreases, which is not preferable. Further, in view of stability in air, it is preferably smaller than 1.3. Furthermore, considering the stability of the discharge capacity, 1.
0 to 1.3 is more preferable.

In addition, LiNi_1-xM_xO_Two(0 <x <
0.5, M is a transition metal or 3B, 4B, 5B group element)
In the production, the lithium compound and nickel compound,
The third component compound has a molar ratio of Li: (Ni + M) of 1:
0.8 or more (Li / (Ni + M) ratio is 0.8 or more)
So that it is weighed. More preferably,
1: 0.8 to 1: 1.3 (Li / (Ni + M) ratio is 0.1.
8 to 1.3), particularly preferably 1: 1.0 to 1: 1.3
(Li / (Ni + M) ratio is 1.0 to 1.3). L
When i / (Ni + M) ratio is less than 0.8, firing
Sometimes LiNi_1-xM _xO_TwoNo crystals developed, discharge capacity
Is small, which is not preferable. Also stability in air
From the above, it is preferable that it is smaller than 1.3. Change
In consideration of the stability of the discharge capacity, 1.0 to 1.3 is
More preferred. Next, a melt that melts at a temperature of 300 ° C or less
Tium compound or nickel compound and temperature below 300 ℃
Nickel compounds or lithium compounds that do not melt at
It is preferable that the mixture is subjected to either treatment of
Yes. Lithium compound or Ni that melts at a temperature of 300 ° C or less
Obtained by melting a nickel compound at a temperature below 300 ° C
Nickelization that does not melt into the melt at temperatures below 300 ° C
The compound or the lithium compound is stirred or kneaded.

A lithium compound or nickel compound that melts at a temperature of 300 ° C. or lower is mixed with a nickel compound or lithium compound that does not melt at a temperature of 300 ° C. or lower, and this is melted at a temperature of 300 ° C. or lower and stirred and kneaded. Here, when nickel nitrate hexahydrate is used as a nickel compound that melts at a temperature of 300 ° C or lower and a lithium compound that does not melt at a temperature of 130 ° C or lower is used, it must be subjected to any of the following treatments. You can

The lithium compound which is not melted at a temperature of 130 ° C. or lower is stirred or kneaded with the melt obtained by melting nickel nitrate hexahydrate at a temperature of 130 ° C. or lower. 'Nickel nitrate hexahydrate and a lithium compound that does not melt at a temperature of 130 ° C or lower are mixed, and this is melted at a temperature of 130 ° C or lower, stirred and kneaded. Also, by adding a third component compound, LiNi _1-x M _x O ₂ (0 <x <0.5, M
Is preferably a transition metal or a 3B, 4B, 5B group element). Lithium compound or 3 that melts at a temperature of 300 ° C or lower
A nickel compound that does not melt at a temperature of 300 ° C or lower, or a lithium compound that does not melt at a temperature of 300 ° C or lower, and a third component compound are stirred in a melt obtained by melting a nickel compound that melts at a temperature of 00 ° C or lower.・ Knead. Lithium compound or 3 that melts at a temperature of 300 ° C or lower
Nickel compound that melts at temperatures below 00 ° C and 300 ° C
A nickel compound that does not melt at the following temperature or a lithium compound that does not melt at a temperature of 300 ° C. or lower and a third component compound are mixed, melted at a temperature of 300 ° C. or lower, and further stirred and kneaded. Here, and, as in the method of ', if one compound is melted and then stirred or kneaded, when a compound having a reaction such as dehydration by the temperature of mixing is used, there is a risk of bumping or the like. Can be excluded. Moreover, the mixing can be performed uniformly. On the other hand, if the compounds are mixed, melted, and stirred and kneaded as in the methods of and, the lithium compound and the nickel compound can be present at the same temperature, so that segregation does not occur. Therefore, it is a simple method that facilitates uniform mixing. Further, the above melting is 3
It is preferable to carry out at a temperature of 00 ° C. or lower. When the temperature is higher than 300 ° C., the stirring or kneading operation for uniform mixing becomes difficult, which is not preferable. Further, in the above'and 'methods, stirring or kneading operation can be carried out at a temperature of 130 ° C. or less, so that even when a nitric acid compound is used as a lithium compound and / or a nickel compound, nitrogen oxides are generated by firing. Can be suppressed.

Here, the term "stirring" is a form of mixing and means an operation of uniformly mixing a liquid (or melt) having a lower viscosity or a mixture of a liquid (or melt) and a solid, "Kneading" is also a form of mixing, and means an operation of uniformly mixing a mixture of a liquid (or melt) having a higher viscosity and a solid. Then, it is preferable to perform calcination for dehydration and denitrification oxide (when a nitric acid compound is used).
In the cases of and, the calcination temperature is from melting point to 700 ° C, preferably melting point to 600 ° C, more preferably 300 to 600 ° C. At a temperature lower than the melting point, dehydration and denitrification oxide become insufficient, which is not preferable.
A temperature higher than 700 ° C. is not preferable because the discharge capacity of the active material obtained by subjecting it to the subsequent main firing becomes small and the characteristics become insufficient. Further, in the case of the'and 'methods, the calcination temperature is 130 to 400 ° C, preferably 300 to 400 ° C. At a temperature lower than 130 ° C, dehydration and denitrification oxide become insufficient, which is not preferable. Temperatures above 400 ° C are not economical.
Note that firing at a temperature of 300 ° C. or higher is more preferable for dehydration and denitrification oxide. Thereby, the management of the subsequent steps (management of the contents of water and nitrogen oxides) can be simplified.

Further cooling or crushing after cooling, and then
LiNi _1-x M _x O by performing main firing at a temperature of 700 to 950 ° C., preferably 700 to 900 ° C., in air or in an oxygen atmosphere in which the volume ratio of oxygen is higher than in air
₂ (0 <x <0.5, M is a transition metal or 3B, 4B, 5
It is preferable to produce Group B elements). The volume ratio of oxygen is more preferably 50 to 100%. After calcination
By cooling and pulverizing the calcined product, the contact area with oxygen during the main calcination increases, and the reaction can be accelerated.

In the main calcination, the calcination at a temperature lower than 700 ° C. causes slow crystal growth, and the calcination at a temperature higher than 950 ° C. decomposes the formed crystal. Therefore, both low and high values are not preferable because the discharge capacity becomes small. Note that even better characteristics can be obtained by firing at a temperature of 900 ° C. or lower. Further, in an atmosphere having an oxygen concentration lower than that in the air, the reaction is slowed down, and crystals are less likely to develop, resulting in a smaller discharge capacity. Therefore, from 50
Even better characteristics can be obtained by firing in a 100% oxygen atmosphere.

LiNi_1-xM_xO_Two(0 <x <0.5,
M is a transition metal or 3B, 4B, 5B group element) and is a positive electrode active material.
The positive electrode used as the material is the Li obtained as described above.
Ni _1-xM_xO_Two(0 <x <0.5, M is a transition metal or
3B, 4B, and 5B elements), a conductive material, a binder, and a case
Depending on the product, it may be formed using a mixture of solid electrolytes
Is done. Conductive agents include carbon black and acetylene
Carbons such as rack and ketjen black, and graphite powder
(Natural graphite, artificial graphite), metal powder, metal fiber, etc.
However, the present invention is not limited to this.

As the binder, there may be used fluoropolymers such as polytetrafluoroethylene and polyvinylidene fluoride, polyolefin polymers such as polyethylene, polypropylene and ethylene-propylene-diene terpolymer, and styrene-butadiene rubber. It is not limited to this. This mixing ratio is the positive electrode active material 10
The conductive material may be 1 to 50 parts by weight and the binder may be 1 to 30 parts by weight with respect to 0 parts by weight. If the amount of the conductive material is less than 1 part by weight, the resistance or polarization of the electrode increases and the discharge capacity decreases, so that a practical secondary battery cannot be manufactured. When the amount of the conductive material is more than 50 parts by weight (the weight part changes depending on the kind of the mixed conductive material), the amount of the active material contained in the electrode is reduced, so that the discharge capacity as the positive electrode becomes small. If the binding material is less than 1 part by weight, the binding ability will be lost, and if it is more than 30 parts by weight, as in the case of the conductive material,
This is not practical because the amount of active material contained in the electrode decreases, and as described above, the resistance or polarization of the electrode increases and the discharge capacity decreases.

To form the above mixture into a positive electrode, a method of compression to form a pellet, or a paste prepared by adding a suitable solvent to the mixture is applied onto a current collector, dried and compressed into a sheet. However, the method is not limited to this. Electrons may be transferred from or to the positive electrode through a current collector. As the current collector, a simple metal, an alloy, carbon or the like is used. For example, titanium, aluminum, stainless steel, etc. are mentioned. Further, copper, aluminum or stainless steel whose surface is treated with carbon, titanium or silver, or those whose surfaces are oxidized may be used. As for the shape, in addition to foil, a film, a sheet, a net, a punched product, a lath body, a porous body, a foamed body, a molded body of a fiber group and the like can be used. The thickness is usually 1 μm to 1 mm, but is not particularly limited.

As the negative electrode, a lithium metal, a lithium alloy and / or a substance capable of inserting and extracting lithium can be used. Examples of lithium alloys include lithium / aluminum alloys, lithium / tin alloys, lithium / lead alloys, and wood alloys. Further, as a substance that can be electrochemically doped / undoped with lithium ions,
For example, conductive polymers (polyacetylene, polythiophene, polyparaphenylene, etc.), pyrolytic carbon, pyrolytic carbon vapor-decomposed in the presence of a catalyst, pitch, coke,
Examples include carbon fired from tar and the like, carbon fired from polymers such as cellulose and phenol resin, and the like. Also,
Lithium ion intercalation / deintercalation graphite (natural graphite, artificial graphite, expanded graphite, etc.), inorganic compounds (WO ₂ , MoO _2, etc.) that can be doped and dedoped with lithium ions, alone or These complexes can be used. Among these negative electrode active materials, pyrolytic carbon, pyrolytic carbon vapor-decomposed in the presence of a catalyst, carbon fired from pitch, coke, tar, etc., carbon fired from a polymer, graphite (natural graphite,
Artificial graphite, expanded graphite, etc.) are preferable because a secondary battery having excellent battery characteristics, especially safety can be manufactured.

As the negative electrode active material, conductive polymer, carbon, graphite,
When the negative electrode is made of an inorganic compound or the like, a conductive material and a binder may be added. The conductive material is carbon black,
Carbons such as acetylene black and Ketjen black, graphite powder (natural graphite, artificial graphite), metal powder, metal fiber and the like can be used, but not limited thereto.

As the binder, polytetrafluoroethylene, polyvinylidene fluoride, and other fluorine-based polymers, polyethylene, polypropylene, ethylene-propylene-diene terpolymer, and other polyolefin-based polymers, and styrene-butadiene rubber can be used. It is not limited to this. As the ionic conductor, for example, an organic electrolytic solution, a solid electrolyte (polymer solid electrolyte, inorganic solid electrolyte), molten salt, or the like can be used. Among these, the organic electrolytic solution is preferably used.

The organic electrolytic solution is composed of an organic solvent and an electrolyte. As the organic solvent, aprotic organic solvents such as propylene carbonate, ethylene carbonate, butylene carbonate, diethyl carbonate, dimethyl carbonate, methyl ethyl carbonate, γ-butyrolactone, methyl formate, and esters such as methyl acetate, tetrahydrofuran, and 2-methyl. Substituted tetrahydrofuran such as tetrahydrofuran, ethers such as dioxolane, diethyl ether, dimethoxyethane, diethoxyethane and methoxyethoxyethane, dimethylsulfoxide, sulfolane, methylsulfolane, acetonitrile and the like can be mentioned. You may use these as 1 type, or 2 or more types of mixed solvent.

Further, as an electrolyte, lithium perchlorate,
Lithium borofluoride, lithium phosphorus fluoride, lithium hexafluoroarsenate, lithium trifluoromethanesulfonate,
Examples thereof include lithium salts such as lithium halide and lithium aluminate chloride. You may use these 1 type or in mixture of 2 or more types. An electrolytic solution is prepared by dissolving the electrolyte in the solvent selected above. The solvent and the electrolyte used when preparing the electrolytic solution are not limited to those listed above.

Known inorganic solid electrolytes include Li nitrides, halides, and oxyacid salts. For example, Li _{3
N, LiI, Li 3 N-} LiI-LiOH, LiSiO
_{4, LiSiO 4 -LiI-LiOH,} Li 3 PO 4 -
Li ₄ SiO _4, phosphorus sulfide compounds, such as Li ₂ SiS _3, and the like. Examples of the organic solid electrolyte include a substance composed of the above electrolyte and a polymer that dissociates the electrolyte, a substance in which the polymer has an ionic dissociation group, and the like. Examples of the polymer that dissociates the electrolyte include a polyethylene oxide derivative or a polymer containing the derivative, a polypropylene oxide derivative, a polymer containing the derivative, and a phosphate ester polymer. In addition, a polymer matrix material containing the aprotic polar solvent,
A mixture of the polymer containing an ion dissociative group and the above aprotic electrolytic solution, or polyacrylonitrile may be added to the electrolytic solution. Inorganic and organic solid electrolytes may be used together.

As the separator for holding these electrolytic solutions, electrically insulating synthetic resin fiber, glass fiber,
Examples include non-woven fabrics such as natural fibers, woven fabrics, micropore structure materials, and powder compacts such as alumina. Of these, synthetic resin non-woven fabrics such as polyethylene and polypropylene, and micropore structures are preferable in terms of quality stability. Some of these synthetic resin non-woven fabrics / micropore structures have the function of separating the positive electrode and negative electrode by melting the separator due to heat when the battery abnormally heats up, and these are also suitable for safety. can do. The thickness of the separator is not particularly limited, but a thickness that can hold a necessary amount of the electrolytic solution and that prevents a short circuit between the positive electrode and the negative electrode is sufficient, and a separator having a thickness of about 0.01 to 1 mm is usually used. Can be, preferably 0.02-0.05m
m.

The shape of the battery can be coins, buttons, sheets, cylinders, corners or the like. In the case of a coin or button type battery, it is common to form the positive electrode and the negative electrode in the form of pellets, put them in a can, and crimp the lid with an insulating packing. In cylindrical and prismatic batteries, the sheet electrode is mainly inserted into the can, the can and the sheet are electrically connected, the electrolytic solution is injected, the sealing body is sealed with an insulating packing, or the sealing body and the can are sealed by a hermetic seal. Insulate and seal to make a battery. At this time, a safety valve provided with a safety element can be used as a sealing body. The safety element includes, for example, a fuse, a bimetal, a PTC element and the like as an overcurrent prevention element. In addition to the safety valve, as a measure for increasing the internal pressure of the battery can, a method of making a crack in the gasket, a method of making a crack in the sealing body, a method of making a cut in the battery can, or the like can be used. Also, an external circuit incorporating measures against overcharge and overdischarge may be used.

Pellets and sheet electrodes are dried in advance,
It is preferably dehydrated. As a drying and dehydrating method, a general method can be used. For example, there is a method of using hot air, vacuum, infrared ray, far infrared ray, electron beam, low humidity wind, or the like, alone or in combination. The drying and dehydration temperatures are preferably in the range of 50 to 380 ° C.

[0038]

The present invention will be specifically described with reference to the following examples. Example 1 - LiNiO ₂ Synthesis lithium nitrate anhydrate and the ratio of lithium and nickel hydroxide Ni Li: Ni 1.1: it was weighed to be 1. Lithium nitrate anhydrous was melted at 270 ° C. Nickel hydroxide preheated to 270 ° C. was mixed into the melt at 270 ° C. and kneaded. After cooling, it was ground in a mortar. Then, main calcination is performed in oxygen at 700 ° C. for 10 hours,
The positive electrode active material LiNiO ₂ was obtained by pulverizing.

Preparation of Electrode LiNiO ₂ obtained as described above was mixed with acetylene black and polytetrafluoroethylene at a ratio of 100: 10: 10 in a mortar, and then pressure molding was performed to obtain a diameter. A pellet having a diameter of 20 mm and a weight of 0.10 g was prepared. A titanium mesh used as a current collector was also added during the pressure molding. A titanium wire was spot-welded from the titanium mesh to collect current, and used as an electrode for evaluation.

Evaluation of Electrode For evaluation, a three-electrode method was used, and lithium was used for the counter electrode and the reference electrode. The electrolyte used was a 1: 1 mixed solvent of ethylene carbonate and ethyl methyl carbonate in which 1 mol / l of lithium perchlorate (LiClO ₄ ) was dissolved.
At a current density of 27.4 mA / g, the reference electrode lithium was first charged to 4.2 V, and then discharged to 2.7 V with the same current. Charge and discharge were repeated in the same potential range and the same current density after the second time. As a result, 1
The discharge capacity for the first time was 158 mAh / g.

Comparative Example 1 LiNiO_TwoSynthesis of lithium nitrate / anhydride and dihydroxide in the same manner as in Example 1.
The ratio of lithium to nickel Li: Ni is 1.1:
Weigh it to 1 and add 2 parts of lithium nitrate / anhydride.
Melt at 70 ℃, preheat to 270 ℃ in the melt
The mixed nickel hydroxide was mixed at 270 ° C.
I didn't do the work. After cooling, it was ground in a mortar. 700
Main baking at 10 ° C in oxygen for 10 hours, crushing, and positive electrode active material L
iNiO _TwoI got

Preparation and Evaluation of Electrode An electrode was prepared in the same manner as in Example 1 and evaluated in the same manner as in Example 1. As a result, the first discharge capacity is 1
It was 30 mAh / g. By comparing Example 1 and Comparative Example 1, it was found that kneading the melted mixture can increase the discharge capacity.

Example 2 and Comparative Example 2 Synthesis of LiNiO _{2 In} the same manner as in Example 1, lithium nitrate / anhydride and nickel hydroxide were used, and the ratio Li: Ni of lithium to nickel was 1.1 :.
Weigh it to 1 and add 2 parts of lithium nitrate / anhydride.
It was melted at 70 ° C., and nickel hydroxide preheated to 270 ° C. was mixed and kneaded in the melt at 270 ° C.
Next, two kinds of kneaded mixtures, one that was only cooled (Example 2) and one that was not cooled and crushed (Comparative Example 2) were respectively main-baked at 700 ° C. in oxygen for 10 hours, It was pulverized to obtain a positive electrode active material LiNiO ₂ .

Preparation and Evaluation of Electrode An electrode was prepared in the same manner as in Example 1 and evaluated in the same manner as in Example 1. As a result, the discharge capacity at the first time was 151 mAh / g in Example 2 and 120 m in Comparative Example 2.
Ah / g. By comparing Examples 1 and 2 with Comparative Example 2, it was found that the discharge capacity can be increased by cooling the kneaded mixture and further pulverizing after cooling.

Examples 3 to 8 and Comparative Examples 3 to 5 ・ Synthesis of LiNiO _{2 In} the same manner as in Example 1, lithium nitrate / anhydride and nickel hydroxide were used, and the ratio of lithium to nickel Li: Ni was 1.1 :.
Weigh it to 1 and add 2 parts of lithium nitrate / anhydride.
It was melted at 70 ° C., and nickel hydroxide preheated to 270 ° C. was mixed and kneaded in the melt at 270 ° C.
After cooling, it was ground in a mortar. Then 600, 650,
Main firing was performed at temperatures of 700, 750, 800, 850, 900, 940, and 980 ° C. in oxygen for 10 hours, and pulverization was performed to obtain a positive electrode active material LiNiO ₂ . These positive electrode active materials were used in Comparative Examples 3 and 4, Examples 3 to 8,
This is Comparative Example 5.

Preparation and Evaluation of Electrode An electrode was prepared in the same manner as in Example 1, and the electrode was evaluated in the same manner as in Example 1. FIG. 1 shows the relationship between the main firing temperature and the first discharge capacity. From FIG. 1, the main firing is 700 to 95.
It can be seen that it is desirable to carry out at a temperature of 0 ° C, preferably 700-900 ° C.

Examples 9 to 14, Comparative Example 6 Synthesis of LiNiO _{2 In} the same manner as in Example 1, lithium nitrate / anhydride and nickel hydroxide were mixed with lithium and nickel having a Li: Ni ratio of 1.1 :.
Weigh it to 1 and add 2 parts of lithium nitrate / anhydride.
It was melted at 70 ° C., and nickel hydroxide preheated to 270 ° C. was mixed and kneaded in the melt at 270 ° C.
After cooling, it was ground in a mortar. Then, at 800 ℃, 2
Time, oxygen concentration in oxygen / nitrogen mixture 10, 30, 5
LiNiO 0, 70, 80 and 100%, and main calcination in air (oxygen concentration 20%), pulverized and positive electrode active material LiNiO
Got _two . These active materials are referred to as Comparative Example 6 and Examples 9 to 14, respectively.

Preparation and Evaluation of Electrode An electrode was prepared in the same manner as in Example 1 and evaluated in the same manner as in Example 1. FIG. 2 shows the relationship between the oxygen concentration in the main firing atmosphere and the first-time discharge capacity. According to FIG. 2, the oxygen concentration in the main firing atmosphere is such that the volume ratio of oxygen is 20 to 100.
%, Preferably 50 to 100% is desirable.

Comparative Example 7 Synthesis of LiNiO ₂ Lithium hydroxide and nickel oxyhydroxide (NiOOH)
Was weighed so that the Li: Ni ratio Li: Ni was 1.1: 1, and then mixed in a mortar to obtain 100 kg / cm.
A pressure of ² was applied to make pellets. 800 ° C
By performing the main calcination for 2 hours in an oxygen atmosphere and pulverizing, LiNiO ₂ as the positive electrode active material could be obtained. -Production and Evaluation of Electrode An electrode was produced in the same manner as in Example 1, and the electrode was evaluated in the same manner as in Example 1. As a result, the first discharge capacity is 1
It was 24 mAh / g.

Comparative Example 8 Synthesis of LiNiO ₂ Lithium hydroxide and nickel oxide (NiO) were weighed so that the lithium: nickel ratio Li: Ni was 1.1: 1, and then mixed in a mortar to give 100 kg / A pressure of cm ² was applied to make pellets. This at 600 ℃ for 24 hours,
After calcination in air, it was calcined at 800 ° C. for 2 hours in an oxygen atmosphere and pulverized to obtain LiNiO ₂ as an active material. -Production and Evaluation of Electrode An electrode was produced in the same manner as in Example 1, and the electrode was evaluated in the same manner as in Example 1. As a result, the first discharge capacity is 1
It was 14 mAh / g.

Comparative Example 9-Synthesis of LiNiO ₂ Lithium hydroxide and nickel chloride were weighed so that the ratio Li: Ni of lithium and nickel was 1: 1 and then dissolved in water to obtain an aqueous solution. While stirring the nickel chloride aqueous solution, slowly add the lithium hydroxide aqueous solution,
Stirred at C for 5 hours. This was dried at a temperature of 90 to 100 ° C. After crushing the resulting solid, 100 kg
Pellets were made by applying a pressure of / cm ² . This is 8
LiNiO ₂ as an active material could be obtained by carrying out a main calcination at 00 ° C. for 2 hours in an oxygen atmosphere and pulverizing.

Preparation and Evaluation of Electrode An electrode was prepared in the same manner as in Example 1 and evaluated in the same manner as in Example 1. As a result, the first discharge capacity is 1
It was 20 mAh / g.

Comparative Example 10 Synthesis of LiNiO ₂ Lithium hydroxide and nickel hydroxide were weighed so that the lithium: nickel ratio Li: Ni was 1: 1, and then a small amount of water was added as a dispersion medium to a mortar. Mixed. This is 9
It was dried at a temperature of 0 to 100 ° C. After crushing the resulting solid material, a pressure of 100 Kg / cm ² was applied to form pellets. This was finally calcined at 800 ° C. for 2 hours in an oxygen atmosphere and pulverized to obtain LiNiO ₂ as an active material. -Production and Evaluation of Electrode An electrode was produced in the same manner as in Example 1, and the electrode was evaluated in the same manner as in Example 1. As a result, the first discharge capacity is 1
It was 10 mAh / g.

Comparative Example 11 Synthesis of LiNiO ₂ Lithium chloride and nickel oxide (NiO) were weighed so that the lithium: nickel ratio Li: Ni was 1: 1 and then lithium chloride was dissolved in water to prepare an aqueous solution. did. While kneading with nickel oxide, a lithium chloride aqueous solution was gradually added, and the mixture was stirred and kneaded at 30 ° C. for 5 hours. 90 to 1
It was dried at a temperature of 00 ° C. After crushing the resulting solid material, a pressure of 100 Kg / cm ² was applied to form pellets. This was finally calcined at 800 ° C. for 2 hours in an oxygen atmosphere and pulverized to obtain LiNiO ₂ as an active material.

Preparation and Evaluation of Electrode An electrode was prepared in the same manner as in Example 1 and evaluated in the same manner as in Example 1. As a result, the first discharge capacity is 1
It was 27 mAh / g. Examples 1 to 19 and Comparative Example 7 to
Comparing No. 11 shows that the present invention using a lithium source and a nickel source having a melting temperature in a specific range can provide a secondary battery having excellent characteristics.

Examples 15 to 23, Comparative Examples 12 and 13 Synthesis of LiNiO ₂ Lithium acetate dihydrate and nickel oxide (NiO) were mixed so that the ratio of lithium to nickel Li: Ni was 1.1: 1. And weighed and mixed. Lithium acetate dihydrate was melted and kneaded at 80 ° C. This is baked at a temperature of 150, 25
0, 300, 400, 500, 600, 650, 70
2 in air at each temperature of 0, 750 and 800 ℃
It was calcined for 4 hours. Moreover, the thing which does not calcination was also prepared. After cooling them, crush them in a mortar and then
This was main-fired in oxygen at 800 ° C. for 2 hours and pulverized to obtain a positive electrode active material LiNiO ₂ . Calcination temperature is 150 and 250
In the case of ℃, and without pre-baking, since the dehydration was not completed yet, bumping occurred during the main baking, but there was no problem in the process. The active material that has not been subjected to calcination is used in Example 15, and further, according to the calcination temperature, Examples 16 and 2 are used.
3 and Comparative Examples 12 and 13.

Preparation and Evaluation of Electrode An electrode was prepared in the same manner as in Example 1 except that the active material, acetylene black and polytetrafluoroethylene were mixed at a ratio of 100: 4: 3. 1m of electrolyte solution in 1: 1 mixed solvent of propylene carbonate and diethyl carbonate
The electrodes were evaluated in the same manner as in Example 1 except that a solution obtained by dissolving ol / l of lithium phosphorus fluoride (LiPF ₆ ) was used.

Here, when the preliminary firing is not performed, 1
The discharge capacity of the first time was 159 mAh / g. FIG. 3 shows the relationship between the calcination temperature and the first discharge capacity. From FIG.
It can be seen that it is desirable to perform calcination at a temperature of 700 ° C. or lower, preferably 600 ° C. or lower, and more preferably 300 to 600 ° C.

Examples 24 to 29, Comparative Examples 14 to 16 Synthesis of LiNiO ₂ Lithium acetate dihydrate and nickel oxide (NiO) were mixed so that the ratio of lithium to nickel Li: Ni was 1.1: 1. And weighed and mixed. Next, lithium acetate dihydrate was melted and kneaded at 80 ° C. This is baked at a temperature of 4
It was calcined at 00 ° C. in air for 24 hours. After cooling them, crush them in a mortar and then in oxygen for 2 hours,
600, 650, 700, 750, 800, 850, 9
Main baking was performed at each temperature of 00, 940, and 980 ° C., and pulverization was performed to obtain a positive electrode active material LiNiO ₂ . These active materials are referred to as Comparative Examples 14 and 15 and Examples 24 to 29 as Comparative Example 16.

Preparation and Evaluation of Electrode An electrode was prepared in the same manner as in Example 15, and the electrode was evaluated in the same manner as in Example 15. FIG. 4 shows the relationship between the main firing temperature and the first discharge capacity. From FIG. 4, the main firing is 700-
It can be seen that it is desirable to carry out at a temperature of 950 ° C, preferably 700-900 ° C.

Examples 30 to 35, Comparative Example 17 Synthesis of LiNiO ₂ Lithium acetate dihydrate and nickel oxide (NiO) were weighed so that the ratio Li: Ni of lithium and nickel was 1.1: 1. And mixed. Next, lithium acetate dihydrate was melted and kneaded at 80 ° C. This is baked at a temperature of 4
It was calcined at 00 ° C. in air for 24 hours. After cooling, it was ground in a mortar. Then, at 800 ° C. for 2 hours, oxygen concentration in oxygen / nitrogen mixture is 10, 30, 50, 70, 8
Main firing was performed in 0 and 100% and in air (oxygen concentration 20%) and pulverization was performed to obtain a positive electrode active material LiNiO ₂ . These active materials were used as Comparative Example 17 and Examples 30 to 35, respectively.
And

Preparation and Evaluation of Electrode An electrode was prepared in the same manner as in Example 15, and the electrode was evaluated in the same manner as in Example 15. The oxygen concentration of the main firing atmosphere,
The relationship of the first discharge capacity is shown in FIG. As shown in FIG. 5, the oxygen concentration in the main firing atmosphere is 20 to 10 in terms of volume ratio of oxygen.
It can be seen that 0%, preferably 50 to 100% is desirable.

Examples 36 to 44, Comparative Examples 18 to 21 Synthesis of LiNiO ₂ Lithium hydroxide and nickel nitrate hexahydrate were weighed so that the Li: Ni ratio Li: Ni was 1.2: 1. And mixed. Next, nickel nitrate hexahydrate was melted and kneaded at 80 ° C. The baking temperature is 100, 1
20, 130, 150, 200, 250, 300, 32
Preliminary calcination was performed in the air at temperatures of 0, 350, 380, 400, 450 and 500 ° C. for 24 hours. After cooling,
It was crushed in a mortar. Subsequently, this was fired in oxygen at 800 ° C. for 2 hours and pulverized to obtain a positive electrode active material LiNiO ₂ . When the calcination temperature was 100 and 120 ° C., dehydration was not completed yet, so bumping occurred during the main calcination, and there was a slight problem in the manufacturing process. Also, in the case of 130 to 200 ° C., dehydration was not complete, but no problem occurred in the process. These active materials were used as Comparative Examples 18 and 19 and Examples 36-4, respectively.
4, Comparative Examples 20 and 21.

Preparation and Evaluation of Electrode An electrode was prepared in the same manner as in Example 1 except that the active material, acetylene black and polytetrafluoroethylene were mixed at a ratio of 100: 5: 5. 1m of electrolyte solution in 1: 1 mixed solvent of propylene carbonate and diethyl carbonate
The electrodes were evaluated in the same manner as in Example 1 except that a solution obtained by dissolving ol / l of lithium phosphorus fluoride (LiPF ₆ ) was used.

FIG. 6 shows the relationship between the calcination temperature and the first discharge capacity. Fig. 6 shows problems in the process (such as bumping during main firing due to insufficient dehydration) and electrical characteristics (discharge capacity does not change even if fired at 400 ° C or higher), and higher than 400 ° C. Since the effect is the same at the temperature, it is understood that the calcination is desirably performed at a temperature of 130 to 400 ° C, preferably 300 to 400 ° C.

Examples 45 to 50, Comparative Examples 22 to 24 Synthesis of LiNiO ₂ Lithium hydroxide and nickel nitrate hexahydrate were weighed so that the Li: Ni ratio Li: Ni was 1.2: 1. And mixed. Next, nickel nitrate hexahydrate was melted and kneaded at 80 ° C. This was calcined at 380 ° C. in air for 24 hours. Then in oxygen, 2
Hours, 600, 650, 700, 750, 800, 85
Main firing was performed at each temperature of 0, 900, 940, and 980 ° C., and pulverization was performed to obtain a positive electrode active material LiNiO ₂ . These active materials were used in Comparative Examples 22 and 23 and Examples 45 to 5, respectively.
0 and Comparative Example 24.

Preparation and Evaluation of Electrode An electrode was prepared in the same manner as in Example 36, and the electrode was evaluated in the same manner as in Example 36. FIG. 7 shows the relationship between the main firing temperature and the first discharge capacity. From FIG. 7, the main firing is 700-
It can be seen that it is desirable to carry out at a temperature of 950 ° C, preferably 700-900 ° C.

Examples 51 to 56, Comparative Example 25 .LiNiO_TwoSynthesis of lithium hydroxide and nickel nitrate hexahydrate with lithium
Weigh the nickel ratio Li: Ni to 1.2: 1.
And mixed. Next, nickel nitrate-6 water at 80 ° C
The Japanese product was melted and kneaded. The firing temperature is set to 380 ° C.
Then, it was calcined in air for 24 hours. After cooling, powder in a mortar
Crushed. Then, at 800 ° C for 2 hours, mixing oxygen and nitrogen
Oxygen concentration in compound 10, 30, 50, 70, 80 and 1
Main firing in 00% and in air (oxygen concentration 20%)
And crushed to produce positive electrode active material LiNiO _TwoI got these
The active materials are referred to as Comparative Example 25 and Examples 51 to 56, respectively.
You.

Preparation and Evaluation of Electrode An electrode was prepared in the same manner as in Example 36, and the electrode was evaluated in the same manner as in Example 36. The oxygen concentration of the main firing atmosphere,
The relationship of the first discharge capacity is shown in FIG. As shown in FIG. 8, the oxygen concentration in the main firing atmosphere is such that the volume ratio of oxygen is 20 to 10.
It can be seen that 0%, preferably 50 to 100% is desirable.

Example 57 Synthesis of LiNiO ₂ Lithium carbonate and nickel nitrate hexahydrate were weighed and mixed so that the ratio of lithium to nickel Li: Ni was 1.3: 1. Next, nickel nitrate hexahydrate was melted and kneaded at 80 ° C. At 400 ° C in air,
It was calcined for 24 hours. After cooling, it was ground in a mortar. Subsequently, this was fired at 700 ° C. in oxygen for 5 hours and pulverized to obtain a positive electrode active material LiNiO ₂ .

Preparation and Evaluation of Electrode Example 1 except that the ratio of the active material to acetylene black and polytetrafluoroethylene was 100: 30: 25.
An electrode was prepared in the same manner as. Electrodes were evaluated in the same manner as in Example 1 except that 1 mol / l of lithium phosphorus fluoride (LiPF ₆ ) was dissolved in a 1: 1 mixed solvent of propylene carbonate and dimethyl carbonate as the electrolytic solution. As a result, the first discharge capacity was 166 mAh.
/ G.

Example 58 Synthesis of Positive Electrode Active Material and Production of Positive Electrode The positive electrode active material LiNiO ₂ was synthesized and a positive electrode was produced in the same manner as in Example 1 to produce a pellet having a diameter of 15 mm and a weight of 50 mg.

Preparation of Negative Electrode The negative electrode is pyrolytic carbon, and nickel is used as a substrate (surface area 4 c
m ² ), and was produced by the atmospheric pressure gas phase pyrolysis method using propane as a starting material. At this time, it was deposited at 750 ° C. for 2 hours. This pyrolytic carbon was obtained by X-ray diffraction (0
The interplanar spacing d ₀₀₂ of the (02) plane is 0.337 nm, and (002)
The crystallite thickness Lc in the plane direction is 15 nm. The peak intensity ratio of around 1360 cm ^-1 to a peak around 1580 cm ^-1 due to the argon laser Raman, i.e. R
The value is 0.48. A nickel wire was spot-welded to this electrode to collect current. 200 ℃ to remove water
The one dried under reduced pressure in 1 was used as a negative electrode. The weight of the active material of this negative electrode was 28 mg.

Evaluation of Battery For the evaluation of the battery, a beaker type cell was used, and the positive electrode and the negative electrode manufactured as described above were used. The electrolyte used was a 1: 1 mixed solvent of propylene carbonate and diethyl carbonate in which 1 mol / l of lithium perchlorate was dissolved. The charge / discharge test was conducted at a current of 0.2 mA at the beginning of 4.
The battery was charged to 4V and then discharged to 2.5V with the same current. After the second time, charging and discharging were repeated in the same voltage range and current density to evaluate the battery. As a result, the first discharge capacity of the battery manufactured as described above was 6.7 m.
Ah, the discharge capacity at the 100th discharge was 6.2 mAh.

Example 59 Synthesis of Positive Electrode Active Material and Production of Positive Electrode A positive electrode active material and LiNiO ₂ were synthesized in the same manner as in Example 16, and a positive electrode was produced in the same manner as in Example 1, and the diameter was 15 mm. A pellet having a thickness of 0.75 mm and a weight of 0.2 g of the active material was prepared.

Manufacture of Negative Electrode As the negative electrode active material, natural graphite produced in Madagascar (scale, particle size 11 μm, d ₀₀₂ 0.337 nm, Lc 27 nm,
La is 17 nm, R value is 0, specific surface area is 8 m ² / g), and each is 10:10 with polytetrafluoroethylene.
After mixing at a ratio of 1, press molding is performed to obtain a diameter of 15
mm, thickness 0.59 mm, and a weight of the active material of 0.1 g. A nickel mesh that acts as a current collector was also added during pressure molding. What was dried under reduced pressure at 200 ° C. to remove water was used as a negative electrode.

Assembling of Battery As shown in FIG. 9, the positive electrode 3 including the positive electrode current collector 2 was pressure-bonded to the positive electrode can 1 on which the insulating packing 8 was placed. next,
A polypropylene non-woven separator 7 is placed on this, ethylene carbonate and propylene carbonate,
An electrolytic solution in which an electrolyte salt LiPF ₆ was dissolved in a mixed solvent of diethyl carbonate at a volume ratio of 2: 1: 3 so as to be 1 mol / l was impregnated.

On the other hand, in order to press-bond the negative electrode 6 containing the negative electrode current collector 5 to the inner surface of the negative electrode can 4, the negative electrode 6 was placed on the separator 7. Then, the positive electrode can 1 and the negative electrode can 4 were caulked with an insulating packing 8 interposed therebetween and hermetically sealed to manufacture a coin-type battery. -Evaluation of batteries All the coin-type batteries that were produced had a charging / discharging current of 1 mA,
The battery was charged up to a charge upper limit voltage of 4.4V, and then discharged up to a discharge lower limit voltage of 2.5V. For evaluation, the discharge capacity of the battery was measured. After the second time, charging and discharging were repeated in the same voltage range and current density to evaluate the battery. As a result, the discharge capacity in the first cycle discharge was 28.5 m.
Ah, the discharge capacity at the 100th cycle was 24.6 mAh.

Example 60 The cylindrical battery shown in FIG. 10 was produced as follows.
The positive electrode is LiN, which is the positive electrode active material synthesized in Example 47.
using iO _2, mixed with the positive electrode active material 100 parts by weight, 10 parts by weight of polyvinylidene fluoride as a conductive material acetylene black powder, 7 parts by weight of a binder to N- methyl-2-pyrrolidone as a dispersing agent, the positive electrode paste And Then, this positive electrode paste was applied onto both sides of a 20 μm thick aluminum foil current collector, dried, and then rolled and cut into strips. Positive electrode lead 1 at one end of the cut electrode
The aluminum tab of No. 5 was attached by spot welding to obtain the positive electrode 14. The positive electrode active material in the positive electrode, lithium nickel oxide, was 40 mg / cm ² .

The negative electrode was made of artificial graphite (particle size 8 μm, d ₀₀₂ 0.337 nm, Lc 25 nm, L
a is 13 nm, R value is 0, specific surface area is 12 m ² / g) 10
0 part by weight and 10 parts by weight of polyvinylidene fluoride as a binder were mixed with N-methyl-2-pyrrolidone as a dispersant to prepare a negative electrode paste. Then, this negative electrode paste was applied to both surfaces of a copper foil current collector having a thickness of 18 μm, dried, rolled, and cut into strips. The nickel tab of the negative electrode lead 17 was attached to one end of the cut electrode by spot welding to obtain the negative electrode 16. The amount of graphite, which is the negative electrode active material in the negative electrode, was 20 mg / cm ² .

The positive electrode 14 and the negative electrode 16 were arranged so as to face each other with the polyethylene microporous separator 18 interposed therebetween, and were spirally wound to form a winding element.
With the positive electrode lead 15 on the upper side and the negative electrode lead 17 on the lower side,
It was inserted into a battery can 13 (diameter 17 mm, height 50 mm, made of stainless steel), the negative electrode lead 17 was spot-welded to the bottom of the battery can 13, and the positive electrode lead 15 was spot-welded to the positive electrode lid 11 with a safety valve. A center pin 19 (diameter 3.4 mm, length 40 m) is provided at the center of the winding element to prevent the winding collapse.
m stainless tube) was inserted. After that, an electrolyte solution in which lithium phosphorus fluoride is dissolved as an electrolyte in a 1: 1 mixed solvent of ethylene carbonate and diethyl carbonate at a ratio of 1 mol / l is poured, and the positive electrode lid 11 is caulked through the insulating packing 12 to form a cylindrical shape. A battery was made.

In the charge / discharge test, charging is performed with a charging current of 500 m.
A, upper limit voltage 4.2V, constant current constant voltage charge and discharge for 3 hours, discharge current 100mA, lower limit voltage 2.75V constant current discharge, was carried out in a constant temperature bath of 25 ℃. as a result,
The initial discharge capacity was 905 mAh, and the battery capacity after 50 cycles was 829 mAh.

Examples 61 to 68, Comparative Example 26 Synthesis of LiNiO ₂ Lithium hydroxide and nickel nitrate hexahydrate were used in a ratio of lithium to nickel of Li: Ni of 0.7: 1 (Li / Ni ratio = 0.7), 0.8: 1 (Li / Ni ratio = 0.8),
0.9: 1 (Li / Ni ratio = 0.9), 1.0: 1 (L
i / Ni ratio = 1.0), 1.1: 1 (Li / Ni ratio =
1.1), 1.2: 1 (Li / Ni ratio = 1.2), 1.
3: 1 (Li / Ni ratio = 1.3), 1.4: 1 (Li / Ni
Ni ratio = 1.4), 1.5: 1 (Li / Ni ratio = 1.
After weighing so as to be 5), lithium hydroxide and nickel nitrate hexahydrate were mixed in a mortar, and this was melted at 80 ° C. and stirred with a stirring rod. This in the air 3
It was calcined at 80 ° C. for 24 hours. After cooling them, oxygen 1
Main firing was carried out in 800% at 800 ° C. for 2 hours to obtain lithium nickel oxide (LiNiO ₂ ) as a positive electrode active material. These active materials are referred to as Comparative Example 26 and Examples 61 to 68, respectively.

A coin type battery was produced in the same manner as in Example 59 except that the above lithium nickel oxide was used as the positive electrode active material. The lithium nickelate used in the coin-type battery was coin-type for each of the Examples and Comparative Examples: a type in which the positive electrode active material itself was not left in the air and a type in which it was left in the air for half a day. An electrode was prepared. FIG. 11 shows the relationship between the first discharge capacity and the lithium-nickel ratio (Li / Ni ratio) at the time of mixing the raw materials for two types of positive electrode active materials, one that does not release into the air and one that is left in the air for half a day. Show. According to FIG. 11, the molar ratio of nickel and lithium is 1: 0.8 or more (L
The i / Ni ratio is 0.8 or more) is preferable in terms of discharge capacity, and the ratio is 1: 0.8 to 1: 1.3 (the Li / Ni ratio is 0.1.
8 to 1.3) is more preferable from the viewpoint of stability in air, and further from 1: 1.0 to 1: 1.3 from the stability of discharge capacity.
It can be seen that (Li / Ni ratio is 1.0 to 1.3) is more preferable.

Examples 69 to 72 Synthesis of Positive Electrode Active Material Lithium hydroxide and nickel nitrate hexahydrate, cobalt nitrate
To hexahydrate, the ratio L of lithium, nickel and cobalt L
i: Ni: Co is 1.1: 0.9: 0.1, 1.1:
0.8: 0.2, 1.1: 0.7: 0.3, 1.1:
Weighed to be 0.6: 0.4. Lithium hydroxide
And nickel nitrate hexahydrate, cobalt nitrate hexahydrate
Mix in a mortar and melt at 80 ° C with a stir bar.
Mixed and stirred. This is heated at a firing temperature of 400 ° C and air
It was calcinated for 24 hours. After cooling, crush in a mortar,
LiNi Ni positive electrode active material after main firing at 00 ° C. in oxygen for 5 hours
_0.9Co _0.1O_Two(Example 69), LiNi_0.8Co
_0.2O_Two(Example 70), LiNi _0.7Co_0.3O
_Two(Example 71), LiNi_0.6Co_0.4O_Two(Example
72) was obtained.

Preparation and Evaluation of Electrode An electrode was prepared in the same manner as in Example 1. The electrolyte solution was mixed with a 1: 1 mixed solvent of propylene carbonate and dimethyl carbonate, and 1 mol / l of lithium phosphorus fluoride (LiPF).
_The electrodes were evaluated in the same manner as in Example 1 except that the one obtained by dissolving ₆ ) was used. As a result, the discharge capacities of the first time were 157, 157, 154 and 153 mAh / g, respectively. Further, the same study of the main calcination temperature as in Examples 3 to 8 and Comparative Examples 3 to 5 was conducted to find the ratio L of lithium to nickel to cobalt.
This was performed for the case where i: Ni: Co was 1.1: 0.8: 0.2. As a result, the same result as in FIG. 1 was obtained.

Further, the same examination as in Examples 9 to 14 and Comparative Example 6 was conducted to examine the oxygen concentration at the time of main firing. Two
I went about the case. As a result, the same result as in FIG. 2 was obtained. Further, in the same manner as in Examples 61 to 68 and Comparative Example 26, the ratio Li: (N
i + Co) (Li / (Ni + Co) ratio)
i: (Ni + Co) (Li / (Ni + Co) ratio) is 0.
7: 1 to 1.5: 1 and Ni: Co = 0.8: 0.2. As a result, the same result as in FIG. 11 was obtained.

Comparative Example 27 Synthesis of Positive Electrode Active Material Lithium hydroxide and nickel oxyhydroxide (NiOO)
H), cobalt oxide (Co _ThreeO_Four) Lithium and Nicke
The ratio Li: Ni: Co of lithium and cobalt is 1.1: 0.8:
After weighing to 0.2, they were mixed in a mortar. Profit
100 kg / cm for the given mixture^TwoApplying pressure
I made a This pellet at 800 ℃ in oxygen at 2:00
Main firing for positive electrode active material LiNi_0.8Co_0.2O_TwoGot
Was. -Preparation and Evaluation of Electrode An electrode was prepared in the same manner as in Example 1, and the same as in Example 1.
The electrodes were evaluated. As a result, the first discharge capacity is 1
It was 38 mAh / g.

Comparative Example 28 Synthesis of Positive Electrode Active Material Lithium hydroxide, nickel chloride and cobalt chloride were used
The ratio Li: Ni: Co of aluminum, nickel and cobalt is 1.
Weigh it to be 1: 0.8: 0.2, and then weigh each with water.
Was dissolved in to form an aqueous solution. Nickel chloride solution and
Baltic aqueous solution is mixed, while stirring the mixed solution,
Lithium hydroxide aqueous solution is gradually added, and the mixture is kept at 30 ° C for 5 hours.
Stirred. The mixed solution is dried at 90 to 100 ° C.
100 kg / cm after crushing the obtained solid material^Two
Pellets were made by applying pressure. 80 this pellet
The positive electrode active material LiNi was calcined at 0 ° C. in oxygen for 2 hours.
_0.8Co _0.2O_TwoI got -Preparation and Evaluation of Electrode An electrode was prepared in the same manner as in Example 1, and the same as in Example 1.
The electrodes were evaluated. As a result, the first discharge capacity is 1
It was 35 mAh / g.

Comparative Example 29 Synthesis of Positive Electrode Active Material Lithium hydroxide, nickel hydroxide, cobalt oxide (Co
₃ O ₄ ) is the ratio of lithium to nickel to cobalt Li: N
After weighing so that i: Co was 1.1: 0.8: 0.2, a small amount of water was added as a dispersion solvent and mixed in a mortar. The obtained mixture was dried at 90 to 100 ° C., the obtained solid was crushed, and then a pressure of 100 kg / cm ² was applied to form pellets. This pellet was subjected to main firing in oxygen at 800 ° C. for 2 hours to obtain a positive electrode active material LiNi _0.8 Co.
_0.2 O ₂ was obtained. -Production and Evaluation of Electrode An electrode was produced in the same manner as in Example 1, and the electrode was evaluated in the same manner as in Example 1. As a result, the first discharge capacity is 1
It was 33 mAh / g.

Comparative Example 30 Synthesis of Positive Electrode Active Material Lithium chloride, nickel oxide (NiO), cobalt oxide
(Co_ThreeO_Four) Is the ratio L of lithium, nickel and cobalt
i: Ni: Co should be 1.1: 0.8: 0.2
Weighed. After this, mix nickel oxide and cobalt oxide
・ Lithium chloride prepared by dissolving lithium chloride in water while kneading.
Gradually add an aqueous solution of um and mix and knead at 30 ° C for 5 hours.
did. This mixture was dried at 90-100 ° C. to obtain
100 kg / cm after crushing the solid material^TwoThe pressure of
Made pellets. This pellet at 800 ℃, oxygen
Medium firing for 2 hours and positive electrode active material LiNi_0.8Co_0.2
O _TwoI got -Preparation and Evaluation of Electrode An electrode was prepared in the same manner as in Example 1, and the same as in Example 1.
The electrodes were evaluated. As a result, the first discharge capacity is 1
It was 37 mAh / g. Examples 69-72 and comparative examples
From 27 to 30, according to the production method of the present invention, lithium
And nickel, cobalt form a more uniform mixture of precursors
Can be prepared by using this precursor.
The capacity can be improved.

Examples 73 to 76 Synthesis of Positive Electrode Active Material Lithium hydroxide, nickel nitrate hexahydrate, and aluminum nitrate nonahydrate were used in a lithium: nickel: aluminum ratio of Li: Ni: Al of 1.1. : 0.95: 0.05,
1.1: 0.9: 0.1, 1.1: 0.85: 0.1
5, weighed to be 1.1: 0.8: 0.2. Nickel nitrate hexahydrate was melted at 80 ° C, and lithium hydroxide preheated to 80 ° C and aluminum nitrate nonahydrate were mixed and stirred in this melt. This was calcinated at a calcination temperature of 400 ° C. in air for 24 hours.
After cooling, the positive electrode active material LiNi _0.95 Al _0.05 O ₂ (Example 73) and LiNi were fired at 700 ° C. in oxygen for 5 hours.
_0.9 Al _0.1 O ₂ (Example 74), LiNi _0.85 Al
_0.15 O ₂ (Example 75), LiNi _0.8 Al _0.2 O
₂ (Example 76) was obtained.

Preparation and Evaluation of Electrode An electrode was prepared in the same manner as in Example 1. The electrolyte solution was mixed with a 1: 1 mixed solvent of propylene carbonate and dimethyl carbonate, and 1 mol / l of lithium phosphorus fluoride (LiPF).
_The electrodes were evaluated in the same manner as in Example 1 except that the one obtained by dissolving ₆ ) was used. As a result, the discharge capacities of the first time were 153, 154, 151 and 151 mAh / g, respectively. Further, the same study of the main firing temperature as in Examples 3 to 8 and Comparative Examples 3 to 5 was carried out for the case where the ratio Li: Ni: Al of lithium, nickel and aluminum was 1.1: 0.9: 0.1. went. As a result, the same result as in FIG. 1 was obtained.

Further, the same examination as in Examples 9 to 14 and Comparative Example 6 on the oxygen concentration at the time of main firing was carried out.
The case of 0.1 was performed. As a result, the same result as in FIG. 2 was obtained. Furthermore, Examples 61 to 68 and Comparative Example 26
In the same manner as described above, the ratio Li: (Ni + Al) (Li / (Ni + Al) ratio of lithium to nickel / aluminum) (Li / (Ni + Al) (Li / (Ni + Al)) was examined.
Ratio) is 0.7: 1 to 1.5: 1 and Ni: Al = 0.
It was carried out for the case of 9: 0.1. As a result, the same result as in FIG. 11 was obtained.

Comparative Example 31 Synthesis of Positive Electrode Active Material Lithium hydroxide and nickel oxyhydroxide (NiOO)
H) and aluminum oxide (Al ₂ O ₃ ) having a lithium: nickel: aluminum ratio of Li: Ni: Al of 1.1:
After weighing so as to be 0.9: 0.1, they were mixed in a mortar. A pressure of 100 kg / cm ² was applied to the resulting mixture to form pellets. The pellets were fired in oxygen at 800 ° C. for 2 hours to perform positive electrode active material LiNi _0.9 Al _0.1.
To give the O _2. -Production and Evaluation of Electrode An electrode was produced in the same manner as in Example 1, and the electrode was evaluated in the same manner as in Example 1. As a result, the first discharge capacity is 1
It was 25 mAh / g.

Comparative Example 32 Synthesis of Positive Electrode Active Material Lithium hydroxide and nickel chloride, aluminum chloride to lithium: nickel: aluminum ratio Li: Ni: Al
Were weighed so as to be 1.1: 0.9: 0.1, and each was dissolved in water to give an aqueous solution. An aqueous solution of nickel chloride and an aqueous solution of aluminum chloride are mixed, and an aqueous solution of lithium hydroxide is gradually added while stirring the mixed solution,
Stirred at C for 5 hours. 90 ~ 100 ℃ this mixed solution
100kg after crushing the solid obtained by drying with
Pellets were made by applying a pressure of / cm ² . The pellets were fired in oxygen at 800 ° C. for 2 hours to perform positive electrode active material L
iNi _0.9 Al _0.1 O ₂ was obtained. -Production and Evaluation of Electrode An electrode was produced in the same manner as in Example 1, and the electrode was evaluated in the same manner as in Example 1. As a result, the first discharge capacity is 1
It was 30 mAh / g.

Comparative Example 33 Synthesis of Positive Electrode Active Material Lithium hydroxide, nickel hydroxide, and aluminum oxide (Al ₂ O ₃ ) were used in a ratio of lithium to nickel to aluminum of Li: Ni: Al of 1.1: 0.9: After weighing to 0.1, a small amount of water was added as a dispersion solvent and mixed in a mortar. The obtained mixture was dried at 90 to 100 ° C., and the obtained solid was crushed, and then 100 kg / cm
A pressure of ² was applied to make pellets. 8 this pellet
LiNi Ni positive electrode active material after main firing at 00 ° C. in oxygen for 2 hours
_0.9 Al _0.1 O ₂ was obtained. -Production and Evaluation of Electrode An electrode was produced in the same manner as in Example 1, and the electrode was evaluated in the same manner as in Example 1. As a result, the first discharge capacity is 1
It was 21 mAh / g.

Comparative Example 34 Synthesis of Positive Electrode Active Material Lithium chloride, nickel oxide (NiO), and aluminum oxide (Al ₂ O ₃ ) were used in a ratio of lithium to nickel to aluminum of Li: Ni: Al of 1.1: 0.9. : Weighed to be 0.1. Thereafter, while mixing and kneading nickel oxide and aluminum oxide, an aqueous lithium chloride solution in which lithium chloride was dissolved was gradually added, and the mixture was mixed and kneaded at 30 ° C. for 5 hours. This mixture was dried at 90 to 100 ° C., the obtained solid was crushed, and then 100 kg / cm
A pressure of ² was applied to make pellets. 8 this pellet
LiNi Ni positive electrode active material after main firing at 00 ° C. in oxygen for 2 hours
To obtain a _{0. 9} Al _0.1 O _2. -Production and Evaluation of Electrode An electrode was produced in the same manner as in Example 1, and the electrode was evaluated in the same manner as in Example 1. As a result, the first discharge capacity is 1
It was 28 mAh / g. From Examples 73 to 76 and Comparative Examples 31 to 34, according to the production method of the present invention, a precursor in which lithium, nickel, and aluminum are more uniformly mixed can be formed, and by using this precursor, Further, the capacity can be improved.

Examples 77-79 Synthesis of Positive Electrode Active Material Lithium hydroxide and nickel nitrate hexahydrate, zinc oxide having a lithium: nickel: zinc ratio Li: Ni: Zn of 1.
1: 0.95: 0.05, 1.1: 0.9: 0.1,
Weighed to be 1.1: 0.85: 0.15. Lithium hydroxide and nickel nitrate hexahydrate, zinc oxide-6
The hydrate was mixed in a mortar, melted at 80 ° C., and mixed and stirred with a stirring rod. This was calcinated at a calcination temperature of 400 ° C. in air for 24 hours. After cooling, the mixture was ground in a mortar and then main-baked at 700 ° C. in oxygen for 5 hours to perform positive electrode active material LiNi _0.95 Zn _0.05 O ₂ (Example 77), LiNi
_0.9 Zn _0.1 O ₂ (Example 78), LiNi _0.85 Zn
_0.15 O ₂ (Example 79) was obtained.

Preparation and Evaluation of Electrode An electrode was prepared in the same manner as in Example 1. The electrolyte solution was mixed with a 1: 1 mixed solvent of propylene carbonate and dimethyl carbonate, and 1 mol / l of lithium phosphorus fluoride (LiPF).
_The electrodes were evaluated in the same manner as in Example 1 except that the one obtained by dissolving ₆ ) was used. As a result, the first discharge capacities were 155, 152 and 151 mAh / g, respectively. Further, the same study of the main firing temperature as in Examples 3 to 8 and Comparative Examples 3 to 5 was conducted to find the ratio Li: Ni: Z of lithium, nickel and zinc.
It carried out about the case where n is 1.1: 0.9: 0.1. As a result, the same result as in FIG. 1 was obtained.

Further, the examination of the oxygen concentration at the time of the main firing similar to Examples 3 to 8 and Comparative Examples 3 to 5 was carried out. The case of 0.1 was performed. As a result, the same result as in FIG. 2 was obtained. Further, in the same manner as in Examples 61 to 68 and Comparative Example 26, the ratio Li: (Ni + Z) of lithium, nickel and zinc was used.
n) (Li / (Ni + Zn) ratio) is examined by Li: (N
i + Zn) (Li / (Ni + Zn) ratio) is 0.7: 1 to
It was performed for 1.5: 1 and Ni: Zn = 0.9: 0.1. As a result, the same result as in FIG. 11 was obtained.

Comparative Example 35 Synthesis of Positive Electrode Active Material Lithium hydroxide and nickel oxyhydroxide (NiOO)
H), zinc oxide (ZnO), lithium, nickel and zinc
Ratio of Li: Ni: Zn becomes 1.1: 0.9: 0.1
After weighing in this way, they were mixed in a mortar. The resulting mixture
100 kg / cm ^TwoMake pellets by applying pressure
Was. The pellets were fired in oxygen at 800 ° C for 2 hours.
Positive electrode active material LiNi_0.9Zn_0.1O_TwoI got -Preparation and Evaluation of Electrode An electrode was prepared in the same manner as in Example 1, and the same as in Example 1.
The electrodes were evaluated. As a result, the first discharge capacity is 1
It was 22 mAh / g.

Comparative Example 36 Synthesis of Positive Electrode Active Material Lithium hydroxide, nickel chloride, and zinc chloride were used in a ratio of lithium: nickel: zinc of Li: Ni: Zn of 1: 0.
After weighing to 9: 0.1, each was dissolved in water to give an aqueous solution. The nickel chloride aqueous solution and the zinc chloride aqueous solution were mixed, and the lithium hydroxide aqueous solution was gradually added while stirring the mixed solution, and the mixture was stirred at 30 ° C. for 5 hours.
The mixed solution was dried at 90 to 100 ° C., the obtained solid matter was crushed, and then a pressure of 100 kg / cm ² was applied to form pellets. This pellet was subjected to main firing in oxygen at 800 ° C. for 2 hours, and the positive electrode active material LiNi _0.9 Zn _0.1
To give the O _2. -Production and Evaluation of Electrode An electrode was produced in the same manner as in Example 1, and the electrode was evaluated in the same manner as in Example 1. As a result, the first discharge capacity is 1
It was 28 mAh / g.

Comparative Example 37 Synthesis of Positive Electrode Active Material Lithium hydroxide, nickel hydroxide, zinc oxide (ZnO)
Was weighed so that the lithium: nickel: zinc ratio Li: Ni: Zn was 1.1: 0.9: 0.1, a small amount of water was added as a dispersion solvent, and the mixture was mixed in a mortar. The obtained mixture was dried at 90 to 100 ° C., the obtained solid was crushed, and then a pressure of 100 kg / cm ² was applied to form pellets. This pellet was subjected to main calcination in oxygen at 800 ° C. for 2 hours to obtain a positive electrode active material LiNi _0.9 Zn _0.1 O ₂ . -Production and Evaluation of Electrode An electrode was produced in the same manner as in Example 1, and the electrode was evaluated in the same manner as in Example 1. As a result, the first discharge capacity is 1
It was 23 mAh / g.

Comparative Example 38 Synthesis of Positive Electrode Active Material Lithium chloride, nickel oxide (NiO), zinc oxide (Z
nO) is a ratio of lithium, nickel and zinc Li: Ni: Z
Weighed so that n was 1.1: 0.9: 0.1. After that, while mixing and kneading nickel oxide and zinc oxide,
An aqueous lithium chloride solution in which lithium chloride was dissolved in water was gradually added, and mixed and kneaded at 30 ° C. for 5 hours. The mixture was dried at 90 to 100 ° C., the obtained solid was crushed, and then a pressure of 100 kg / cm ² was applied to form pellets. This pellet was subjected to main calcination in oxygen at 800 ° C. for 2 hours to obtain a positive electrode active material LiNi _0.9 Zn _0.1 O ₂ . -Production and Evaluation of Electrode An electrode was produced in the same manner as in Example 1, and the electrode was evaluated in the same manner as in Example 1. As a result, the first discharge capacity is 1
It was 26 mAh / g. From Examples 77 to 79 and Comparative Examples 35 to 38, according to the production method of the present invention, a precursor in which lithium, nickel, and zinc are more uniformly mixed can be formed, and by using this precursor, Further, the capacity can be improved.

From Examples 69 to 79 and Comparative Examples 27 to 38, according to the manufacturing method of the present invention, lithium and nickel,
A precursor in which other elements are more uniformly mixed can be formed, and the capacity can be further improved by using this precursor. Therefore, the present invention is directed to LiNi _1-x
M _x O (0 <x <0.5, M is a transition metal or 3B, 4
It is possible to provide an excellent method for producing B and 5B elements).

[0107]

According to the present invention, a lithium compound or 3 which melts at a temperature of 300 ° C. or less is used.
A melt obtained by melting a nickel compound that melts at a temperature of 00 ° C. or lower is mixed with a nickel compound that does not melt at a temperature of 300 ° C. or lower, or a lithium compound that does not melt at a temperature of 300 ° C. or lower, or 300 ° C. A lithium compound or nickel compound that melts at the temperature below is mixed with a nickel compound or lithium compound that does not melt at a temperature of 300 ° C or less, and this is mixed at 300 ° C.
An oxygen atmosphere in which the mixture is melted at the following temperature, stirred and kneaded, and then the obtained mixture is cooled or cooled and then pulverized, and the temperature is 700 to 950 ° C. and the volume ratio of oxygen in air is higher than that in air. LiNi, which is a positive electrode active material, after being fired under
It is characterized by producing O ₂ .

Therefore, a mixture in which the lithium compound and the nickel compound are uniformly mixed is obtained, and the positive electrode active material having a stable discharge capacity of about 160 mAh / g can be obtained by firing the mixture. Further, the non-aqueous secondary battery using this positive electrode active material improves reliability.
Furthermore, it has excellent charge / discharge characteristics and cycle characteristics.

The molar ratio of nickel and lithium is 1: 0.8.
˜1: 1.3 (Li / Ni ratio of 0.8 to 1.3) to obtain a positive electrode active material and a non-aqueous secondary battery having excellent stability of lithium nickelate in air. You can Further, the molar ratio of nickel and lithium is 1: 1.0 to
By setting the ratio to 1: 1.3 (the Li / Ni ratio is 1.0 to 1.3), the stability of the discharge capacity of lithium nickelate (ie, even if the change in the molar ratio of nickel and lithium is almost the same) It is possible to obtain a positive electrode active material and a non-aqueous secondary battery having excellent discharge capacity).

[Brief description of drawings]

FIG. 1 is a relationship diagram of a main firing temperature and a first-time discharge capacity for Examples 3 to 8 and Comparative Examples 3 to 5.

FIG. 2 is a graph showing the relationship between the oxygen concentration in the main firing atmosphere and the first discharge capacity for Examples 9 to 14 and Comparative Example 6.

FIG. 3 is a relationship diagram of the calcination temperature and the first discharge capacity for Examples 16 to 23 and Comparative Examples 12 and 13.

FIG. 4 is a diagram showing the relationship between the main firing temperature and the first-time discharge capacity for Examples 24 to 29 and Comparative Examples 14 to 16.

FIG. 5 is a relationship diagram between the oxygen concentration in the main firing atmosphere and the discharge capacity for the first time for Examples 30 to 35 and Comparative Example 17.

FIG. 6 is a graph showing the relationship between the calcination temperature and the first discharge capacity for Examples 36 to 44 and Comparative Examples 18 to 21.

FIG. 7 is a relationship diagram of the main firing temperature and the first-time discharge capacity for Examples 45 to 50 and Comparative examples 22 to 24.

FIG. 8 is a relationship diagram between the oxygen concentration in the main firing atmosphere and the first discharge capacity for Examples 51 to 56 and Comparative Example 25.

FIG. 9 is a schematic cross-sectional view of a coin battery used in an example.

FIG. 10 is a schematic sectional view of a cylindrical battery used in an example.

FIG. 11 is a diagram showing the relationship between lithium and nickel ratio (Li / Ni ratio) and the discharge capacity at the first time for Examples 61 to 68 and Comparative Example 26.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Positive electrode can 2 Positive electrode current collector 3 Positive electrode 4 Negative electrode can 5 Negative electrode current collector 6 Negative electrode 7 Separator 8 Insulating packing 11 Positive electrode lid with safety valve 12 Insulating packing 13 Battery can 14 Positive electrode 15 Positive electrode lead 16 Negative electrode 17 Negative electrode lead 18 Separator 19 Center pin

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tetsuya Yoneda 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Within Sharp Corporation (72) Kazuaki Minato 22-22 Nagaike-cho, Abeno-ku, Osaka, Osaka Inside the company, (72) Inventor Tokuyo Iida, 45 characters, Shirokata-cho, Fukui City, Fukui Prefecture 5-10 Sunamawari, Tanaka Chemical Research Institute, Inc. (72) Tetsuji Makino, 45 characters, Shirakata-cho, Fukui City, Fukui Prefecture Sand beach division 5-10 shares in Tanaka Chemical Research Institute (72) Inventor Shigeyuki Hamano 45 characters Shirakata-cho, Fukui City, Fukui Prefecture Sand beach division 5-10 shares in Tanaka Chemical Research Institute (72) Inventor Kameda Yusumi Fukui Prefecture Fukui City, Shirokata-cho, 45 letters, sand beach division, 5-10 shares, Tanaka Chemical Research Institute (72) Inventor, Tomohiko Inada, Fukui, Fukui-shi, 45 letters, sand beach division, 5-10 shares, Tanaka Chemical Research Institute

Claims (11)

[Claims] 1. A molten material obtained by melting a lithium compound that melts at a temperature of 300 ° C. or lower, or a nickel compound that melts at a temperature of 300 ° C. or lower, and a nickel compound or 300 ° C. that does not melt at a temperature of 300 ° C. or lower. After mixing with a lithium compound that does not melt at the following temperatures, the resulting mixture is cooled or crushed after cooling, and at a temperature of 700 to 950 ° C. and in air or an oxygen atmosphere in which the volume ratio of oxygen is higher than in air. A method for producing a positive electrode active material, which comprises firing lithium nickel oxide (LiNiO ₂ ) which is a positive electrode active material by firing below. 2. A lithium compound or a nickel compound that melts at a temperature of 300 ° C. or lower and a nickel compound or a lithium compound that does not melt at a temperature of 300 ° C. or lower are mixed, and this is melted at a temperature of 300 ° C. or lower and stirred and kneaded. And cooling or crushing after cooling the resulting mixture, 700-950
Manufacture of a positive electrode active material characterized in that lithium nickel oxide (LiNiO ₂ ) as a positive electrode active material is manufactured by firing at a temperature of ℃ and in an oxygen atmosphere in which the volume ratio of oxygen is higher than that in air. Method. 3. The production method according to claim 1, wherein the mixture is further calcined before cooling or crushing after cooling. 4. The nickel compound that melts at a temperature of 300 ° C. or lower is nickel nitrate hexahydrate, and the lithium compound that does not melt at a temperature of 300 ° C. or lower is lithium hydroxide anhydrate or monohydrate. , Lithium oxide, lithium carbonate, lithium oxalate, lithium chloride, lithium bromide / anhydride or monohydrate, lithium iodide / anhydride, lithium acetate / anhydride.
The manufacturing method according to any one of claims. 5. The lithium compound that melts at a temperature of 300 ° C. or lower is selected from at least one of lithium nitrate / anhydride or trihydrate, lithium acetate / dihydrate and lithium iodide / trihydrate. , Nickel compounds that do not melt at temperatures of 300 ° C or lower are nickel oxide, nickel hydroxide, nickel oxyhydroxide, nickel carbonate, basic nickel carbonate monohydrate, nickel acetate tetrahydrate, nickel oxalate Hydrate, nickel formate dihydrate, nickel chloride
The manufacturing method according to any one of claims 1 to 3, wherein at least one is selected from an anhydride and hexahydrate. 6. The nickel compound that melts at a temperature of 300 ° C. or lower is nickel nitrate hexahydrate, the lithium compound is a compound that does not melt at a temperature of 130 ° C. or lower, and the melting temperature is 130 ° C. The manufacturing method according to claim 1, wherein the firing is performed at a temperature of 130 to 400 ° C. 7. A lithium compound which does not melt at a temperature of 130 ° C. or lower is lithium nitrate / anhydride or trihydrate, lithium hydroxide / anhydride or monohydrate, lithium oxide, lithium carbonate, lithium oxalate, or chloride. 7. The method according to claim 6, wherein at least one of lithium, lithium bromide / anhydride or monohydrate, lithium iodide / anhydride and lithium acetate / anhydride is selected. 8. A lithium compound that melts at a temperature of 300 ° C. or lower or a nickel compound that melts at a temperature of 300 ° C. or lower, and a nickel compound that does not melt at a temperature of 300 ° C. or lower or a lithium compound that does not melt at a temperature of 300 ° C. or lower. , A transition metal compound or a compound containing a 3B, 4B, or 5B group element, cooled or crushed after cooling, and then main-fired in air or in an oxygen atmosphere in which the volume ratio of oxygen is higher than that of air, and the positive electrode active material LiNi _1-x M _x O ₂ (0 <x
<0.5, M is a transition metal or 3B, 4B, 5B group element)
A method for producing a positive electrode active material, comprising: 9. The manufacturing method according to claim 8, which further comprises performing preliminary calcination before the main calcination. 10. A transition metal compound or a compound containing a 3B, 4B, or 5B group element, which melts at a temperature of 300 ° C. or lower,
Ti, V, Cr, Mn, Fe, Co, Cu, Zn, Y,
Zr, Nb, Mo, La, W, Al, In, Sn, P
The production method according to claim 8 or 9, which is a compound containing b, Sb, and Bi. 11. LiNi _1-x M _x O ₂ (0 ≦ ₁ manufactured by the manufacturing method according to claim 1.
x <0.5, M is a positive electrode containing a positive electrode active material made of a transition metal or 3B, 4B, and 5B elements), a negative electrode, and an ionic conductor.