JP3233352B2 - Manufacturing method of non-aqueous solvent secondary battery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a non-aqueous solvent secondary battery having an improved positive electrode active material.

[0002]

2. Description of the Related Art In recent years, with the reduction in size and weight of various electronic devices such as VTRs, mobile phones, and mobile computers, the demand for secondary batteries having a high energy density has increased as a power source for these devices. Research on non-aqueous solvent secondary batteries has been actively conducted. Already, a lithium ion secondary battery using LiCoO ₂ as a positive electrode active material has been put to practical use as a high energy density secondary battery.

A non-aqueous solvent secondary battery uses lithium, a lithium alloy or a compound capable of occluding and releasing lithium ions as a negative electrode, and uses propylene carbonate (P) as an electrolyte.
C), ethylene carbonate (EC), ethyl methyl carbonate (EMC), dimethyl carbonate (DM
C), diethyl carbonate (DEC), 1,2-dimethoxyethane (DME), γ-butyl lactone (γ-B
L), tetrahydrofuran (THF), 2-methyltetrahydrofuran (2-MeTHF) or other non-aqueous solvent.
iClO ₄ , LiBF ₄ , LiAsF ₆ , LiPF ₆ ,
It is composed of a material in which a lithium salt (electrolyte) such as LiCF ₃ SO ₃ or LiAlCl ₄ is dissolved. Further, as the positive electrode, a positive electrode containing an active material utilizing intercalation or doping of a layered compound has been attracting attention.

As an example utilizing the intercalation of the layered compound, a chalcogenide compound has relatively excellent charge / discharge cycle characteristics. However,
Chalcogenide compounds have a low electromotive force, and even when lithium metal is used as the negative electrode, the practical charging voltage is at most about 2 V, which does not satisfy the point of high electromotive force which is a feature of non-aqueous solvent secondary batteries. Did not.

On the other hand, V ₂ O ₅ , which has a similar layered structure,
Metal oxide compounds such as V ₆ O ₁₃ , LiCoO ₂ , LiNiO ₂ , and LiMn ₂ O ₄ utilizing a doping phenomenon have attracted attention because of their high electromotive force characteristics. In particular, a positive electrode containing LiCoO ₂ or LiNiO ₂ as an active material has an electromotive force of about 4 V and has a large theoretical energy density of about 1 kWh / kg per positive electrode active material.

[0006] However, a non-aqueous solvent secondary battery provided with a positive electrode containing LiNiO ₂ as an active material has low large-current discharge characteristics, and further, is overcharged due to a short circuit between the electrodes inside the battery or a failure or malfunction of the charging device. When an abnormal current flows due to, for example, the positive electrode active material thermally decomposes, abnormal heat generation of 300 ° C. or more occurs, the non-aqueous electrolyte decomposes, the internal pressure rises sharply, and there is a risk of explosion or ignition. is there.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for manufacturing a non-aqueous solvent secondary battery having an improved discharge voltage, excellent large-current charge / discharge characteristics, and improved safety in abnormal situations. Is what you do.

[0008]

The method of manufacturing a non-aqueous solvent secondary battery according to the present invention satisfies the following equations (1) and (2).
In a method for manufacturing a non-aqueous solvent secondary battery including a positive electrode including a lithium nickel-based composite oxide as a positive electrode active material and a negative electrode that occludes and releases lithium ions, the positive electrode active material includes water, an acidic aqueous solution, Preparing a slurry in which a raw material mixture containing a Ni component and a Li component is dispersed in a solvent selected from an alkaline aqueous solution and an organic solvent, spray drying the slurry, and firing the dried product in an oxidizing atmosphere; A heat treatment in a pressurized oxidizing atmosphere. 0.75 ≦ FWHM (003) / FWHM (104) ≦ 0.9 (1) 0.25 ≦ I (104) / I (003) ≦ 0.9 (2) where FWHM (003) in the expression (1). ) Is CuKα
Index hkl of powder X-ray diffraction using X-ray
The half width of the diffraction peak on the (003) plane, FWHM (10
4) is the Miller index h of powder X-ray diffraction using CuKα radiation.
The half width of the diffraction peak on the (104) plane at kl is shown.
In the formula (2), I (003) uses CuKα radiation.
(003) at the Miller index hkl of the powder X-ray diffraction
Integral intensity of diffraction peak on plane, I (104) is CuKα
Index hkl of powder X-ray diffraction using X-ray
It shows the integrated intensity of the diffraction peak on the (104) plane.

[0009]

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a non-aqueous solvent secondary battery (for example, a cylindrical non-aqueous solvent secondary battery) according to the present invention will be described with reference to FIG.

A bottomed cylindrical container 1 made of, for example, stainless steel has an insulator 2 disposed at the bottom. Electrode group 3
Are stored in the container 1. The electrode group 3 includes:
It has a structure in which a belt-like material in which a positive electrode 4, a separator 5 and a negative electrode 6 are laminated in this order is spirally wound.

A non-aqueous electrolyte is contained in the container 1. A PTC element 7 having an opening in the center,
A safety valve 8 disposed on the TC element 7 and a hat-shaped positive terminal 9 disposed on the safety valve 8 are caulked and fixed to an upper opening of the container 1 via an insulating gasket 10. The positive electrode terminal 9 has a vent hole (not shown). One end of the positive electrode lead 11 is connected to the positive electrode 4, and the other end is connected to the PTC element 7. The negative electrode 6 is connected to the container 1 as a negative terminal via a negative lead (not shown).

Next, the positive electrode 4, the separator 5, the negative electrode 6, and the non-aqueous electrolyte will be described in detail.

1) Positive Electrode 4 This positive electrode contains a positive electrode active material composed of a lithium nickel composite oxide satisfying the following formulas (1) and (2).

0.75 ≦ FWHM (003) / FWHM (104) ≦ 0.9 (1) where FWHM (003) is CuKα in the expression (1).
Half width of diffraction peak at (003) plane at Miller index hkl of powder X-ray diffraction using X-ray, FWHM (10
4) is the Miller index h of powder X-ray diffraction using CuKα radiation.
The half width of the diffraction peak on the (104) plane at kl is shown.

0.25 ≦ I (104) / I (003) ≦ 0.9 (2) In the equation (2), I (003) is represented by ((k) in Miller index hkl of powder X-ray diffraction using CuKα ray. 00
3) Integrated intensity of diffraction peak on plane, I (104) is Cu
3 shows the integrated intensity of the diffraction peak on the (104) plane at the Miller index hkl of powder X-ray diffraction using Kα radiation.

As the lithium nickel composite oxide,
LiNiO ₂ , a composite oxide in which a part of nickel of LiNiO ₂ is substituted by an element, a composite oxide in which a part of nickel and oxygen of LiNiO ₂ are partially substituted by an element, and the like can be given.

As a composite oxide obtained by substituting a part of nickel of LiNiO ₂ with an element, the composition formula is LiNi _1-x M _x
O ₂ (where M is at least one element selected from Co, Mn, B, Al and Li, and the atomic ratio x is in the range of 0 <x ≦ 0.5) Oxides are preferred. The composite oxide represented by the above composition formula uses only Li as M, that is, Li _{1 + y} Ni _1-y O ₂
(Where the atomic ratio y is in the range of 0 <y ≦ 0.1). M is more preferably Co, Mn, or Al.

The atomic ratio x is defined in the above range for the following reason. When the atomic ratio x exceeds 0.5, nickel ions easily mix into lithium ion sites, and there is a possibility that an active material satisfying the above formulas (1) and (2) may not be obtained. A more preferable range of the atomic ratio x is 0.1 ≦ x ≦ 0.3.

The atomic ratio y is defined in the above range for the following reason. If the atomic ratio y exceeds 0.1, the crystal structure becomes unstable, so that sufficient charge / discharge cycle characteristics may not be obtained. A more preferable range of the atomic ratio y is 0.01 ≦ y ≦ 0.05.

As a composite oxide in which a part of nickel and oxygen of LiNiO ₂ is substituted by an element, Li _{1 + z} Ni
_1-xz M _x O _2-z F _z (where the atomic ratio x is 0 <x ≦ 0.
In the range of 5, the atomic ratio z is in the range of 0 <z ≦ 0.25).

The atomic ratio x is defined in the above range for the following reason. When the atomic ratio x exceeds 0.5, nickel ions easily mix into lithium ion sites, and there is a possibility that an active material satisfying the above formulas (1) and (2) may not be obtained. A more preferable range of the atomic ratio x is 0.1 ≦ x ≦ 0.3.

The atomic ratio z is defined in the above range for the following reason. When the atomic ratio z exceeds 0.25, even if the active material satisfies the conditions of the above formulas (1) and (2), diffusion of lithium ions may be hindered, so that a high charge / discharge capacity is obtained. May not be possible. A more preferable range of the atomic ratio z is 0 <z ≦ 0.1.

The average valence of nickel in the positive electrode active material is preferably 2.9 or more and 3.1 or less. This is due to the following reasons. If the average valence of nickel is less than 2.9, the amount of divalent nickel in the crystal increases, so that it may be difficult to obtain sufficient discharge capacity and large current discharge characteristics. In other words, since divalent nickel easily mixes into lithium sites, it not only prevents diffusion of lithium ions during charging and discharging, but also has a function of keeping the charge in the crystal neutral when divalent nickel is present. -The amount of lithium ions that can be released is reduced.
For this reason, sufficient discharge capacity and large current discharge characteristics may not be obtained. On the other hand, when the average valence of nickel exceeds 3.1, lithium deficiency may have occurred. When lithium deficiency occurs, the amount of lithium ions that can be inserted and extracted decreases, and thus it may not be possible to obtain a sufficient discharge capacity and large current discharge characteristics.
The more preferable range of the average valence of nickel is 2.95 or more and 3.05 or less.

The crystal structure of the lithium nickel composite oxide is a layered structure and belongs to a trigonal system. Lithium ions are inserted and extracted from a direction orthogonal to the trigonal c-axis. Miller index hk of powder X-ray diffraction using CuKα ray
The (003) plane in 1 relates to the c-axis direction of the trigonal system. On the other hand, the (104) plane at the Miller index hkl of the powder X-ray diffraction using CuKα rays relates to a direction orthogonal to the c-axis of the trigonal system.

FWHM (003) / F in equation (1)
The reason why the WHM (104) is specified in the above range is as follows. FWHM (003) / FWHM
If (104) exceeds 0.9, trigonal c-axis orientation is low (crystal growth in the c-axis direction is insufficient), and a large amount of nickel ions are mixed in lithium ion sites. Such an active material has the following problems (a) to (c).

(A) Since the c-axis orientation of the trigonal system is low,
When the crystal grows in the direction perpendicular to the c-axis, the diffusion movement distance of lithium ions becomes longer. (B) When the crystal structure has a large disorder of nickel ions, the valence of nickel ions becomes less than 3. As a result, the function of maintaining the charge in the crystal at neutral occurs, so that the amount of lithium ions that can be inserted and extracted decreases. (C) Nickel ions mixed into lithium ion sites prevent lithium ions from diffusing into the active material.

Therefore, the reaction resistance of the active material at the time of charge and discharge increases, and the amount of lithium ion occlusion and release decreases, so that the discharge potential decreases and the large-current discharge characteristics decrease. In addition, an active material having a high reaction resistance at the time of charge / discharge causes thermal decomposition at a low temperature, so that an abnormal temperature causes a rapid temperature rise.

FWHM (003) / FWHM (104)
Is smaller, the c-axis orientation of the trigonal system becomes higher, and the disorder of nickel ions tends to decrease, but FWHM (003) / FWHM (104)
Is less than 0.75, crystal growth in the direction perpendicular to the c-axis is inferior to crystal growth in the c-axis direction. The expansion and contraction of the crystal due to the charge / discharge reaction are c-axis and a
It has been found to occur along the axial direction. Since lithium ions are absorbed and released from a direction perpendicular to the c-axis, the degree of expansion and contraction in the c-axis direction is larger than that in the a-axis direction. If the crystal growth in the c-axis direction is relatively large,
Since a large number of expansions and contractions in the c-axis direction, which are originally large, are accumulated, the degree of expansion and contraction of the active material is significantly increased, and the cycle characteristics are degraded. FWHM (00
3) The more preferred range of / FWHM (104) is 0.
8 ≦ FWHM (003) / FWHM (104) ≦ 0.8
5

The half width FWH of the diffraction peak of the (003) plane
M (003) is 0.1 ° ≦ FWHM (003) ≦ 0.
It is preferable to set the angle to 16 °. By setting the above range, the discharge capacity and the discharge potential can be further improved. More preferably, 0.12 ° ≦ FWHM (00
3) ≦ 0.15 °.

The half width FWH of the diffraction peak of the (104) plane
M (104) is 0.13 ° ≦ FWHM (104) ≦
It is preferable that the angle be in the range of 0.2 °. By setting the content in this range, crystal growth in a direction perpendicular to the c-axis of the trigonal system can be suppressed, and the orientation of the c-axis can be appropriately increased. More preferably 0.14 ° ≦ FWHM
(104) ≦ 0.18 °.

In the equation (2), I (104) / I (00
The reason why 3) is defined in the above range is as follows. When I (104) / I (003) exceeds 0.9, a large amount of nickel ions are mixed into lithium ion sites. As a result, the amount of lithium ions that can be stored and released is reduced, and the reaction resistance of the active material during charging and discharging is increased, so that the discharging potential is reduced and the large-current charging and discharging characteristics are reduced. When I (104) / I (003) is reduced, the disorder of nickel ions is reduced, but when I (104) / I (003) is less than 0.25, the active material and the electrolytic solution easily react. . I (104)
/ I (003) is 0.25 ≦ I (104) / I (00
3) It is more preferable to set the range of ≦ 0.8.

The positive electrode active material has a particle diameter D10, D5 having a cumulative volume frequency of 10, 50, and 90% of the particle diameter distribution of the secondary particles.
It is preferable that 0 and D90 satisfy 0.3 ≦ (D10 / D50) ≦ 0.8 and 1 ≦ (D90 / D50) ≦ 3.
This is due to the following reasons. D10 / D5
When 0 is less than 0.3, it indicates that many fine particles are contained. If there are many fine particles, the cycle characteristics may be significantly reduced. In addition, when D10 / D50 exceeds 0.8, when D90 / D50 is less than 1, and when D90 / D50 exceeds 3, when the electrode is manufactured, the filling amount of the active material is reduced. The discharge capacity of the battery may decrease. D10, D50, D90
Are 0.4 ≦ (D10 / D50) ≦ 0.7 and 1.2 ≦
More preferably, (D90 / D50) ≦ 2.5 is satisfied.

When D10, D50 and D90 satisfy the above-mentioned specific relation, D50 is not less than 0.2 μm and not more than 5 μm.
It is preferably 0 μm or less. This is due to the following reasons. When D50 is less than 0.2 μm,
Crystal growth may be insufficient and sufficient discharge capacity may not be obtained. On the other hand, when D50 exceeds 50 μm, it may be difficult to obtain a uniform electrode surface when producing an electrode. A more preferable range of D50 is 1 μm or more and 25 μm or less.

The specific surface area of the positive electrode active material is 0.2 to 2
It is preferably m ² / g. The specific surface area is 0.2
If it is less than m ² / g, the contact area between the positive electrode active material and the electrolytic solution may decrease, and a sufficient discharge capacity may not be obtained. Furthermore, the charging / discharging efficiency may decrease due to the decrease in the reaction area. On the other hand, the specific surface area is 2 m ² / g
If the reaction area exceeds the threshold value, the decomposition reaction of the electrolyte is likely to occur with an increase in the reaction area. In this case, abnormal heat generation, rupture and ignition of the battery are likely to occur. A more preferable range of the specific surface area is 0.3 m ² / g or more and 1.5 m ² / g or less.

The positive electrode active material is produced, for example, by the method described below.

(First Step) The starting compounds are mixed in a predetermined molar ratio, and this is dispersed in an aqueous solvent, an acidic aqueous solution, an alkaline aqueous solution, or an organic solvent such as methanol, ethanol, or acetone. The resulting slurry is spray dried.

Once the starting compounds are dispersed in a solvent and spray-dried, it becomes possible to mix the starting compounds more uniformly than to mix the solid starting compounds.

As a raw material compound, nickel hydroxide [N
i (OH) ₂ ], nickel carbonate (NiCO ₃ ), nickel oxide (NiO), nickel nitrate [Ni (NO ₃ ) ₂ ]
Nickel compounds such as lithium hydroxide (LiOH),
Lithium oxide (Li ₂ O), lithium carbonate (Li ₂ CO
₃ ), lithium compounds such as lithium nitrate (LiNO ₃ ), lithium halide salts such as lithium fluoride (LiF), cobalt hydroxide [Co (OH) ₂ ], cobalt carbonate (CoCO ₃ ), cobalt oxide (CoO, Co
₂ O ₃ ), cobalt compounds such as cobalt nitrate [Co (NO ₃ ) ₂ ], manganese oxide (MnO ₂ ), manganese carbonate (MnCO ₃ ), manganese nitrate [Mn (NO ₃ ) ₂ ]
Such as manganese compounds, boric acid (H ₃ BO ₃ ), lithium tetraborate (Li ₂ B ₄ O ₇ ), boron oxide (B
₂ O ₃ ), lithium tetrahydride borate (LiB
H ₄ ), aluminum hydroxide [Al
Aluminum compounds such as (OH) ₃ ], aluminum oxide (Al ₂ O ₃ ), aluminum sulfate [Al ₂ (SO ₄ ) ₃ ], aluminum nitrate [Al (NO ₃ ) ₃ ], C
The surface of nickel hydroxide in which at least one element selected from the group consisting of o, Mn and Al is coprecipitated is coated with Co, Mn and A
and those coated with a hydroxide of at least one element selected from l.

Further, when synthesizing a compound oxide obtained by replacing a part of composite oxide and LiNiO ₂ nickel and oxygen was replaced with an element part of LiNiO ₂ nickel element, an LiNiO ₂ as the starting compound be able to.

(Second step) The above-mentioned raw material compound was prepared at 650-750 ° C in an oxidizing atmosphere having an oxygen concentration of 18-100%.
Hold (fire) for more than an hour.

The oxidizing atmosphere may contain an inert gas such as an argon gas or a nitrogen gas. When the oxygen concentration is less than 18%, lithium carbonate,
A large amount of unreacted products such as nickel oxide may remain. Unreacted products not only prevent the active material from absorbing and releasing lithium ions, but also cause a decrease in discharge potential. By setting the oxygen concentration in the oxidizing atmosphere to 18% or more, unreacted products can be reduced, and the incorporation of nickel ions into lithium ion sites can be suppressed. An active material that satisfies the formula can be obtained.

The holding temperature is defined in the above range for the following reason. Below 650 ° C,
Since the reaction is insufficient, a large amount of unreacted product remains, and a large amount of nickel ions are mixed into the lithium ion site, there is a possibility that an active material satisfying the above formulas (1) and (2) may not be obtained. is there. On the other hand, when the temperature exceeds 750 ° C., oxygen is desorbed due to a decomposition reaction, so that a large amount of nickel oxide having extremely high reaction resistance may adhere to the surface of the active material. Nickel oxide is a factor that inhibits the reaction of inserting and extracting lithium ions.

(Third Step) In an oxidizing atmosphere pressurized to 0.1 to 50 MPa and an oxygen concentration of 18 to 100% (oxygen partial pressure is 0.018 MPa to 50 MPa)
s or less) Heat treatment is performed at 450 to 900 ° C. for 1 hour or more.

By this step, the c-axis orientation in the crystal structure can be controlled to a desired level.

The oxidizing atmosphere may contain an inert gas such as an argon gas or a nitrogen gas. Further, it is preferable that the oxygen concentration in the atmosphere is defined in the above range for the same reason as described above.

The heat treatment temperature is defined in the above range for the following reason. If the temperature is lower than 450 ° C., since crystal growth and crystal rearrangement are extremely slow, it is difficult to obtain a crystal structure having a desired half width.
On the other hand, when the temperature exceeds 900 ° C., although crystal growth and crystal rearrangement proceed, a deoxygenation reaction occurs on the particle surface, and a high-resistance layer may be formed.

The reason why the pressure of the heat treatment atmosphere is defined in the above range is as follows. 0.1MPas
When a heat treatment is performed below, a large amount of nickel oxide or lithium carbonate that inhibits occlusion and release of lithium ions may remain because a deoxygenation reaction easily occurs. on the other hand,
When the heat treatment is performed at 50 MPa or more, distortion occurs in the crystal, which may lead to structural deterioration as the charge / discharge cycle proceeds.

(Fourth Step) Slow cooling is performed at a rate of 50 ° C. or less per hour.

When the cooling rate exceeds 50 ° C./hour, nickel ions are likely to be mixed into the lithium ion sites, so that an active material satisfying the above formulas (1) and (2) may not be obtained. . Cooling rate 50 ° C / hour
By doing so, mixing of nickel ions into lithium ion sites can be suppressed, and ordering of the layered structure can be improved.

The positive electrode is prepared, for example, by suspending a positive electrode active material, a conductive agent and a binder in an appropriate solvent, applying the resulting mixture slurry to a current collector, and drying and forming a thin plate. It is produced by cutting to a desired size. At this time, it is preferable that the coating amount on one side is in the range of 100 to 400 g / m ² . Further, the positive electrode is prepared by kneading the positive electrode active material together with the conductive agent and the binder, or kneading the positive electrode active material together with the conductive agent and the binder, and attaching the sheet to the current collector. May be.

Examples of the conductive agent include acetylene black, carbon black, graphite and the like.

Examples of the binder include polyvinylidene fluoride (PVdF), a vinylidene fluoride-6-propylene propylene copolymer, a vinylidene fluoride-tetrafluoroethylene-6-propylene propylene terpolymer, and a fluorine-containing copolymer. Vinylidene fluoride-pentafluoropropylene copolymer, vinylidene fluoride-chlorotrifluoroethylene copolymer,
Tetrafluoroethylene-vinylidene fluoride copolymer,
Tetrafluoroethylene-perfluoroalkylvinyl ether (PFA) -vinylidene fluoride terpolymer,
Tetrafluoroethylene-hexafluoropropylene (FEP) -vinylidene fluoride terpolymer, tetrafluoroethylene-ethylene-vinylidene fluoride terpolymer, chlorotrifluoroethylene-vinylidene fluoride copolymer, chlorotrifluoro Ethylene-ethylene-vinylidene fluoride terpolymer, vinyl fluoride-vinylidene fluoride copolymer, ethylene-propylene-diene copolymer (EPDM), styrene-butadiene rubber (SB
R) and the like can be used.

The mixing ratio of the positive electrode active material, the conductive agent and the binder was 80 to 95% by weight of the positive electrode active material, 3 to 2% of the conductive agent.
It is preferably in the range of 0% by weight and 2 to 10% by weight of the binder.

As the current collector, for example, an aluminum foil, a stainless steel foil, a titanium foil or the like can be used. However, in consideration of tensile strength, electrochemical stability, flexibility at the time of winding, etc., the aluminum foil may be used. Most preferred. At this time, the thickness of the foil is 10 μm or more and 30 μm or more.
m or less.

2) Negative Electrode 6 It is preferable that the negative electrode 6 contains a compound capable of inserting and extracting lithium ions.

Examples of the compound that occludes and releases lithium ions include conductive polymers such as polyacetal, polyacetylene, and polypyrrole that can be doped with lithium ions, and organic compounds that can be doped with lithium ions. Examples of the carbon material include a body.

The characteristics of the carbon material vary considerably depending on the raw material and the firing method. Examples of the material include a graphite-based carbon material, a carbon material having a mixture of graphite crystal parts and amorphous parts, and a carbon material having a turbostratic structure having no regularity in the lamination of crystal layers.

The negative electrode is prepared by, for example, suspending the compound capable of inserting and extracting lithium ions and a binder in an appropriate solvent, applying the mixture slurry to a current collector, and drying the mixture to form a thin plate. Is cut into a desired size. At this time, the coating amount on one side is 50 to 200 g / m
It is preferred to be in the range of ² . In addition, the compound that absorbs and releases lithium ions is formed into a pellet together with a binder, or the compound that absorbs and releases lithium ions is kneaded together with a binder, and then formed into a sheet and adhered to the current collector. Thus, the negative electrode may be manufactured.

As the binder, the same binder as described for the positive electrode can be used.

The mixing ratio of the negative electrode material and the binder is preferably in the range of 80 to 98% by weight of the negative electrode material and 2 to 20% by weight of the binder.

As the current collector, for example, a copper foil, a nickel foil or the like can be used, but a copper foil is most preferable in consideration of electrochemical stability and flexibility at the time of winding. At this time, the thickness of the foil is 8 μm or more and 20 μm or more.
It is preferably not more than μm.

3) Non-aqueous electrolyte The non-aqueous electrolyte has a composition in which an electrolyte is dissolved in a non-aqueous solvent.

As the non-aqueous solvent, for example, propylene carbonate (PC), ethylene carbonate (E
C), ethyl methyl carbonate (EMC), dimethyl carbonate (DMC), diethyl carbonate (DE
C), 1,2-dimethoxyethane (DME), diethoxyethane (DEE), γ-butyrolactone (γ-B
L), one or a mixture of two or more selected from tetrahydrofuran (THF), 2-methyltetrahydrofuran (2-MeTHF), 1,3-dioxolan, and 1,3-dimethoxypropane.

Examples of the electrolyte include lithium perchlorate (LiClO ₄ ) and lithium borofluoride (LiBF).
₄ ), one selected from lithium arsenide hexafluoride (LiAsF ₆ ), lithium hexafluorophosphate (LiPF ₆ ), lithium trifluoromethosulfonate (LiCF ₃ SO ₃ ), and lithium aluminum tetrachloride (LiAlCl ₄ ) Alternatively, two or more lithium salts can be used. The amount of the electrolyte dissolved in the non-aqueous solvent is 0.5 to 1.5.
Preferably, it is mol / L.

The non-aqueous solvent secondary battery according to the present invention described in detail above includes a positive electrode containing a lithium nickel-based composite oxide satisfying the above-mentioned formulas (1) and (2) as a positive electrode active material. Such an active material has a layered crystal structure in which trigonal c-axis orientation is appropriately high and nickel ions are prevented from being mixed into lithium ion sites. The active material can increase the amount of lithium ions that can be inserted and extracted, and can easily and promptly diffuse lithium ions during the charge / discharge reaction. Can be reduced.
As a result, a secondary battery provided with a positive electrode containing the active material,
Since the discharge potential can be increased, large current discharge characteristics can be improved. At the same time, it is possible to suppress the occurrence of thermal decomposition of the positive electrode active material when an internal short circuit occurs in the charged state or an abnormal current flows due to overcharging due to a failure or malfunction of the charging device. Therefore, a rapid rise in temperature can be avoided, and rupture and ignition can be prevented.

The composition of the positive electrode active material was LiNi _1-x M _x
O ₂ (where M is at least one element selected from Co, Mn, B, Al and Li, and the atomic ratio x is in the range of 0 <x ≦ 0.5) Or Li _{1 + y} Ni _1-y O ₂ (where the atomic ratio y is in the range of 0 <y ≦ 0.1), whereby excessive charge and discharge reaction is caused. Can suppress the change in the crystal structure of the secondary battery, so that the charge and discharge cycle life of the secondary battery can be improved. Moreover, since the specific surface area on the surface of the secondary particles when the positive electrode active material takes the form of secondary particles can be reduced, the decomposition reaction of the non-aqueous electrolyte on the surface of the active material can be suppressed.

A three-electrode glass cell was prepared by using a positive electrode containing a lithium nickel-based composite oxide satisfying the above-mentioned formulas (1) and (2) as a positive electrode active material, and a counter electrode and a reference electrode made of metallic lithium. And charge / discharge cycle test (charging; performed at a constant current of 1 mA / cm ² up to 4.2 V, and after reaching 4.2 V, the current was reduced to 1/10 at a constant voltage.
The discharge was performed until the voltage reached 3 V at a constant current of 1 mA / cm ² until the voltage reached 3 V. After performing 50 cycles, the positive electrode was taken out of the glass cell and subjected to powder X-ray diffraction using CuKα radiation. , Peak intensity ratio I (104)
/ I (003) was in the range of 0.25 to 0.4, and the half width ratio FWHM (003) / FWHM (104) was in the range of 0.75 to 0.9.

[0069]

Embodiments of the present invention will be described below in detail with reference to the drawings. Example 1 A 3 mol / L aqueous solution of lithium hydroxide was added to nickel hydroxide powder at a molar ratio of Li: Ni of 1.02: 1.
Then, the mixture was sufficiently mixed, and then spray-dried. The obtained dried product was kept at a temperature of 700 ° C. for 48 hours while introducing an oxygen stream so that the oxygen concentration became 95% or more. The obtained product is maintained at an oxygen concentration of 95% or more by introducing an oxygen stream, and then 1M
A heat treatment was performed at 800 ° C. for 5 hours while pressurizing to Pas.

The obtained product was subjected to powder X-ray diffraction using CuKα radiation to find that the composition was LiNiO 2.
₂ and the peak intensity ratio I (104) / I (00
3), FWHM (003), FWHM (104) and half width width ratio FWHM (003) / FWHM (104) were found to be the values shown in Table 1 below. In addition, the LiN
Table 2 below shows the D50 and the specific surface area of the iO ₂ powder.

Next, 90% by weight of the above-mentioned LiNiO ₂ powder and 5% by weight of acetylene black were mixed in a ball mill for 1 hour, and then dissolved in N-methylpyrrolidone so that polyvinylidene fluoride became 5% by weight. To
A mixture slurry was prepared while keeping the humidity at 20% or less. This mixture slurry is applied to aluminum foil, dried,
A positive electrode was produced by roll pressing.

Further, the mesophase pitch-based carbon fiber was graphitized at 3000 ° C. in an argon gas atmosphere, and further heat-treated in a chlorine gas atmosphere at 2400 ° C. to synthesize a graphitized carbon powder. Subsequently, 94% by weight of the graphitized carbon powder and 6% by weight of polyvinylidene fluoride were dissolved in N-methylpyrrolidone to prepare a mixture slurry. This mixture slurry was applied to a copper foil, dried, and roll-pressed to produce a negative electrode.

After laminating the positive electrode, the separator composed of a polypropylene microporous film, and the negative electrode in this order, a spirally wound electrode group was prepared so that the negative electrode was the outermost periphery.

Further, a non-aqueous electrolyte was prepared by dissolving 1.0 mol / L of LiPF ₆ in a mixed solvent of ethylene carbonate and ethyl methyl carbonate (mixing volume ratio 1: 2).

The above-mentioned electrode group and the above-mentioned non-aqueous electrolyte are housed in a stainless steel bottomed cylindrical container, and sealed, etc. to assemble the above-mentioned cylindrical non-aqueous solvent secondary battery having the structure shown in FIG. Was.

Example 2 Ni _0.83 Co _0.17 (OH) ₂
3 mol in cobalt coprecipitated nickel hydroxide powder represented by
/ L lithium hydroxide aqueous solution was added dropwise so that the molar ratio of Li: (Ni + Co) became 1.02: 1, and after sufficient mixing, spray drying was performed. While introducing the oxygen stream so that the oxygen concentration becomes 95% or more,
It was kept at a temperature of 00 ° C. for 48 hours. The resulting product was introduced into an oxygen stream to maintain the oxygen concentration at 95% or more, and then heated at 800 ° C. for 5 hours while pressurizing to 1 MPa.

The obtained product was subjected to powder X-ray diffraction using CuKα radiation to find that the composition was LiNi
_0.83 Co _0.17 O ₂ , peak intensity ratio I (104)
/ I (003), FWHM (003), FWHM (10
4) and the half width width ratio FWHM (003) / FWHM (10
4) was found to be the value shown in Table 1 below. Also,
The D50 and specific surface area of the LiNi _0.83 Co _0.17 O ₂ powder are shown in Table 2 below.

The cylindrical non-aqueous solvent secondary battery shown in FIG. 1 was assembled in the same manner as in Example 1 except that the obtained LiNi _0.83 Co _0.17 O ₂ powder was used as a positive electrode active material.

Example 3 Ni _0.83 Co _0.17 (OH) ₂
3 mol of cobalt coprecipitated nickel hydroxide powder represented by
/ L in aluminum nitrate aqueous solution: Al: (Ni + Co)
Were dispersed so that the molar ratio of the mixture became 0.02: 1. A 3 mol / L aqueous solution of sodium hydroxide was added dropwise thereto, and the mixture was continuously reacted while maintaining the temperature at 40 to 60 ° C while stirring. A 3 mol / L aqueous lithium hydroxide solution was added to the obtained product at a molar ratio of Li: (Ni + Co + Al) of 1.0.
The mixture was added dropwise at a ratio of 2: 1 and sufficiently mixed, followed by spray drying. The obtained dried product was kept at a temperature of 700 ° C. for 48 hours while introducing an oxygen stream so that the oxygen concentration became 95% or more. After the obtained product is introduced so as to maintain the oxygen concentration at 95% or more by introducing an oxygen stream,
Heat treatment was performed at 800 ° C. for 5 hours while pressurizing to 1 MPa.

The obtained product was subjected to powder X-ray diffraction using CuKα radiation to find that the composition was LiNi
_0.81 Co _0.17 Al _0.02 O ₂ , peak intensity ratio I
(104) / I (003), FWHM (003), FW
HM (104) and half width width ratio FWHM (003) / FW
HM (104) was found to be the value shown in Table 1 below. Table 2 below shows the D50 and specific surface area of the LiNi _0.81 Co _0.17 Al _0.02 O ₂ powder.

The obtained LiNi _0.81 Co _0.17 Al _0.02 O
_The cylindrical non-aqueous solvent secondary battery shown in FIG. 1 was assembled in the same manner as in Example 1 except that the _two powders were used as the positive electrode active material.

Example 4 Ni _0.83 Co _0.17 (OH) ₂
Was dispersed in a 1 mol / L aqueous solution of aluminum nitrate so that the molar ratio of Al: (Ni + Co) was 0.003: 1. A 3 mol / L aqueous sodium hydroxide solution was added dropwise thereto, and the mixture was continuously reacted with stirring at a temperature of 40 to 60 ° C., and the surface was coated with aluminum hydroxide. To the obtained product, a 3 mol / L aqueous lithium hydroxide solution was added dropwise so that the molar ratio of Li: (Ni + Co + Al) was 1.02: 1, and after sufficient mixing, spray drying was performed. The resulting dried product is adjusted to an oxygen concentration of 9
While introducing an oxygen stream so as to be 5% or more, 700
C. for 48 hours. The resulting product was introduced into an oxygen stream to maintain the oxygen concentration at 95% or more, and then heated at 800 ° C. for 5 hours while pressurizing to 1 MPa.

When the obtained product was subjected to powder X-ray diffraction using CuKα ray, the composition was LiNi
_0.827 Co _0.17 Al _0.003 O ₂ , peak intensity ratio I (104) / I (003), FWHM (003), F
WHM (104) and half-width ratio FWHM (003) / F
It was found that WHM (104) had the values shown in Table 1 below. In addition, the LiNi _0.827 Co _0.17 Al _0.003 O
The D50 and specific surface area of the _two powders are shown in Table 2 below.

The obtained LiNi _0.827 Co _0.17 Al
_The cylindrical non-aqueous solvent secondary battery shown in FIG. 1 was assembled in the same manner as in Example 1 except that _0.003 O ₂ powder was used as the positive electrode active material.

Example 5 Ni _0.83 Co _0.17 (OH) ₂
Was dispersed in a 1 mol / L aqueous solution of aluminum nitrate so that the molar ratio of Al: (Ni + Co) was 0.003: 1. A 3 mol / L aqueous sodium hydroxide solution was added dropwise thereto, and the mixture was continuously reacted with stirring at a temperature of 40 to 60 ° C., and the surface was coated with aluminum hydroxide. To the obtained product, a 3 mol / L aqueous lithium hydroxide solution was added dropwise so that the molar ratio of Li: (Ni + Co + Al) was 1.02: 1, and after sufficient mixing, spray drying was performed. The resulting dried product is adjusted to an oxygen concentration of 9
While introducing an oxygen stream so as to be 5% or more, 710
C. for 48 hours. The resulting product was introduced into an oxygen stream to maintain the oxygen concentration at 95% or more, and then heated at 800 ° C. for 5 hours while pressurizing to 1 MPa.

The obtained product was subjected to powder X-ray diffraction using CuKα radiation to find that the composition was LiNi
_0.827 Co _0.17 Al _0.003 O ₂ , peak intensity ratio I (104) / I (003), FWHM (003), F
WHM (104) and half-width ratio FWHM (003) / F
It was found that WHM (104) had the values shown in Table 1 below. In addition, the LiNi _0.827 Co _0.17 Al _0.003 O
The D50 and specific surface area of the _two powders are shown in Table 2 below.

The obtained LiNi _0.827 Co _0.17 Al
_The cylindrical non-aqueous solvent secondary battery shown in FIG. 1 was assembled in the same manner as in Example 1 except that _0.003 O ₂ powder was used as the positive electrode active material.

Example 6 Ni _0.83 Co _0.17 (OH) ₂
Was dispersed in a 1 mol / L aqueous solution of aluminum nitrate so that the molar ratio of Al: (Ni + Co) was 0.003: 1. A 3 mol / L aqueous sodium hydroxide solution was added dropwise thereto, and the mixture was continuously reacted with stirring at a temperature of 40 to 60 ° C., and the surface was coated with aluminum hydroxide. To the obtained product, a 3 mol / L aqueous lithium hydroxide solution was added dropwise so that the molar ratio of Li: (Ni + Co + Al) was 1.02: 1, and after sufficient mixing, spray drying was performed. The resulting dried product is adjusted to an oxygen concentration of 9
While introducing an oxygen stream so as to be 5% or more, 700
C. for 5 hours. The resulting product was introduced into an oxygen stream to maintain the oxygen concentration at 95% or more, and then heated at 600 ° C. for 5 hours while pressurizing to 1 MPa.

The obtained product was subjected to powder X-ray diffraction using CuKα radiation to find that the composition was LiNi
_0.827 Co _0.17 Al _0.003 O ₂ , peak intensity ratio I (104) / I (003), FWHM (003), F
WHM (104) and half-width ratio FWHM (003) / F
It was found that WHM (104) had the values shown in Table 1 below. In addition, the LiNi _0.827 Co _0.17 Al _0.003 O
The D50 and specific surface area of the _two powders are shown in Table 2 below.

The obtained LiNi _0.827 Co _0.17 Al
_The cylindrical non-aqueous solvent secondary battery shown in FIG. 1 was assembled in the same manner as in Example 1 except that _0.003 O ₂ powder was used as the positive electrode active material.

Example 7 3 mol of nickel hydroxide powder
It was dispersed in a 1 / L manganese nitrate aqueous solution so that the molar ratio of Mn: Ni was 1: 4. A 3 mol / L aqueous solution of sodium hydroxide was added dropwise thereto, and the mixture was continuously reacted while maintaining the temperature at 40 to 60 ° C while stirring. A 3 mol / L aqueous lithium hydroxide solution was added to the obtained product by Li:
The mixture was dropped so that the molar ratio of (Ni + Mn) was 1.02: 1, and after sufficiently mixing, spray drying was performed. The obtained dried product was kept at a temperature of 700 ° C. for 48 hours while introducing an oxygen stream so that the oxygen concentration became 95% or more. The obtained product was introduced into an oxygen stream to maintain the oxygen concentration at 95% or more, and then heated at 800 ° C. for 5 hours while pressurizing to 1 MPa.

The obtained product was subjected to powder X-ray diffraction using CuKα radiation to find that the composition was LiNi
_0.8 Mn _0.2 O ₂ , peak intensity ratio I (104)
/ I (003), FWHM (003), FWHM (10
4) and the half width width ratio FWHM (003) / FWHM (10
4) was found to be the value shown in Table 1 below. Also,
Table 2 below shows the D50 and specific surface area of the LiNi _0.8 Mn _0.2 O ₂ powder.

The cylindrical non-aqueous solvent secondary battery shown in FIG. 1 was assembled in the same manner as in Example 1 except that the obtained LiNi _0.8 Mn _0.2 O ₂ powder was used as a positive electrode active material.

Example 8 Nickel hydroxide powder and lithium fluoride were added to a 3 mol / L lithium hydroxide aqueous solution by L.
i: Ni: F molar ratio of 1.05: 0.95: 0.05
After thoroughly dispersing and thoroughly mixing, spray drying was performed. The obtained dried product was kept at a temperature of 700 ° C. for 48 hours while introducing an oxygen stream so that the oxygen concentration became 95% or more. The obtained product is maintained at an oxygen concentration of 95% or more by introducing an oxygen stream, and then 1M
A heat treatment was performed at 800 ° C. for 5 hours while pressurizing to Pas.

The obtained product was subjected to powder X-ray diffraction using CuKα radiation to find that the composition was Li _1.05 N
i _0.95 O _1.95 F _0.05 , and the peak intensity ratio I (10
4) / I (003), FWHM (003), FWHM
(104) and half width width ratio FWHM (003) / FWHM
(104) was found to be the value shown in Table 1 below.
Also, the D50 of the Li _1.05 Ni _0.95 O _1.95 F _0.05 powder
The specific surface area is shown in Table 2 below.

The cylindrical non-aqueous solvent secondary battery shown in FIG. 1 was assembled in the same manner as in Example 1 except that the obtained Li _1.05 Ni _0.95 O _1.95 F _0.05 powder was used as a positive electrode active material.

Example 9 Ni _0.83 Co _0.17 (OH) ₂
Are mixed so that the molar ratio of B: (Ni + Co) becomes 0.02: 1, and then the cobalt: coprecipitated nickel hydroxide powder represented by the formula: and lithium tetraborate (Li ₂ B ₄ O ₇ ) are mixed.
A 3 mol / L aqueous solution of sodium hydroxide was added dropwise so that the molar ratio of (Ni + Co + B) was 1.02: 1, and after sufficient mixing, spray drying was performed. The obtained dried product was kept at a temperature of 700 ° C. for 48 hours while introducing an oxygen stream so that the oxygen concentration became 95% or more. The obtained product was introduced into an oxygen stream to maintain the oxygen concentration at 95% or more, and then heated at 800 ° C. for 5 hours while pressurizing to 1 MPa.

The obtained product was subjected to powder X-ray diffraction using CuKα radiation to find that the composition was LiNi
_0.81 Co _0.17 B _0.02 O ₂ , and the peak intensity ratio I (1
04) / I (003), FWHM (003), FWHM
(104) and half width width ratio FWHM (003) / FWHM
(104) was found to be the value shown in Table 1 below.
The D5 of the LiNi _0.81 Co _0.17 B _0.02 O ₂ powder
0 and the specific surface area are shown in Table 2 below.

The obtained LiNi _0.81 Co _0.17 B _0.02 O ₂
The cylindrical non-aqueous solvent secondary battery shown in FIG. 1 was assembled in the same manner as in Example 1 except that the powder was used as the positive electrode active material.

Example 10 Ni _0.83 Co _0.17 (OH)
_The cobalt coprecipitated nickel hydroxide powder represented by ₂ and lithium fluoride are mixed at a molar ratio of Li: Ni: Co: F of 1.0.
3 mo so that 5: 0.81: 0.17: 0.05
After being dispersed in a 1 / L aqueous lithium hydroxide solution and thoroughly mixed, spray drying was performed. The resulting dried product is introduced into an oxygen stream at an oxygen concentration of 95% or more, while
It was kept at a temperature of 0 ° C. for 48 hours. The obtained product was introduced into an oxygen stream to maintain the oxygen concentration at 95% or more, and then heated at 800 ° C. for 5 hours while pressurizing to 1 MPa.

The obtained product was subjected to powder X-ray diffraction using CuKα radiation to find that the composition was Li _1.05 N
i _0.81 Co _0.17 O _1.95 F _0.05 , the peak intensity ratio I
(104) / I (003), FWHM (003), FW
HM (104) and half width width ratio FWHM (003) / FW
HM (104) was found to be the value shown in Table 1 below. In addition, the Li _1.05 Ni _0.81 Co _0.17 O _1.95 F _0.05
The D50 and specific surface area of the powder are shown in Table 2 below.

The obtained Li _1.05 Ni _0.81 Co _0.17 O _1.95
Except for using the F _0.05 powder as a cathode active material, it was assembled a cylindrical non-aqueous solvent secondary battery shown in FIG. 1 described above the same as in Example 1.

Example 11 Ni _0.83 Co _0.17 (OH)
3mo Co-precipitated nickel hydroxide powder represented by ₂
It was dispersed in a 1 / L manganese nitrate aqueous solution so that the molar ratio of Mn: (Ni + Co) became 0.02: 1. A 3 mol / L aqueous solution of sodium hydroxide was added dropwise thereto, and the mixture was continuously reacted while maintaining the temperature at 40 to 60 ° C while stirring. A 3 mol / L aqueous lithium hydroxide solution was added to the obtained product at a molar ratio of Li: (Ni + Co + Mn) of 1.0.
The mixture was added dropwise at a ratio of 2: 1 and sufficiently mixed, followed by spray drying. The obtained dried product was kept at a temperature of 700 ° C. for 48 hours while introducing an oxygen stream so that the oxygen concentration became 95% or more. The obtained product was introduced into an oxygen stream to maintain the oxygen concentration at 95% or more, and then heated at 800 ° C. for 5 hours while pressurizing to 1 MPa.

The obtained product was subjected to powder X-ray diffraction using CuKα radiation to find that the composition was LiNi
_0.81 Co _0.17 Mn _0.02 O ₂ , peak intensity ratio I
(104) / I (003), FWHM (003), FW
HM (104) and half width width ratio FWHM (003) / FW
HM (104) was found to be the value shown in Table 1 below. Table 2 below shows D50 and specific surface area of the LiNi _0.81 Co _0.17 Mn _0.02 O ₂ powder.

The resulting LiNi _0.81 Co _0.17 Mn _0.02 O
_The cylindrical non-aqueous solvent secondary battery shown in FIG. 1 was assembled in the same manner as in Example 1 except that the _two powders were used as the positive electrode active material.

Example 12 Ni _0.83 Co _0.17 (OH)
_The cobalt coprecipitated nickel hydroxide powder represented by ₂ , aluminum hydroxide and lithium tetraborate were mixed with B: Al: Mn:
The molar ratio of (Ni + Co) is 0.02: 0.02: 0.0
A 3 mol / L aqueous solution of manganese nitrate was dispersed in a 3 mol / L aqueous solution of manganese nitrate so as to have a ratio of 3: 1. Was. In the obtained product, Li:
The molar ratio of (Ni + Co + Mn + Al + B) is 1.02:
A 3 mol / L aqueous solution of lithium hydroxide was added dropwise so as to be 1, and after sufficiently mixing, spray drying was performed. The obtained dried product was kept at a temperature of 700 ° C. for 5 hours while introducing an oxygen stream so that the oxygen concentration became 95% or more. The resulting product was maintained at an oxygen concentration of 95% or more by introducing an oxygen stream, and then heated at 800 ° C. for 5 hours while pressurizing to 1 MPa.

The obtained product was subjected to powder X-ray diffraction using CuKα radiation to find that the composition was LiNi
_0.77 Co _0.16 Mn _0.03 Al _0.02 B _0.02 O ₂ , peak intensity ratio I (104) / I (003), FWHM (0
03), FWHM (104) and half-width ratio FWHM (0
03) / FWHM (104) was found to be the value shown in Table 1 below. In addition, the LiNi _0.77 Co _0.16 Mn
Table 2 shows the D50 and specific surface area of the _0.03 Al _0.02 B _0.02 O ₂ powder.

The obtained LiNi _0.77 Co _0.16 Mn _0.03 A
l _0.02 B _0.02 O ₂ powder was used as the positive electrode active material,
The cylindrical non-aqueous solvent secondary battery shown in FIG. 1 was assembled in the same manner as in Example 1.

Example 13 Ni _0.83 Co _0.17 (OH)
_The cobalt coprecipitated nickel hydroxide powder represented by ₂ , aluminum hydroxide, lithium tetraborate, and lithium fluoride have a molar ratio of Li: B: Al: Mn: (Ni + Co) of 1.
05: 0.02: 0.02: 0.03: 0.95 A 3 mol / L aqueous solution of sodium hydroxide was added dropwise to a dispersion of 3 mol / L aqueous manganese nitrate so as to obtain a temperature of 40 to The reaction was continuously performed while stirring at a temperature of 60 ° C. Li: (Ni + Co +
An aqueous solution of 3 mol / L lithium hydroxide was added dropwise so that the molar ratio of (Mn + Al + B) was 1.05: 0.95,
After thorough mixing, spray drying was performed. The obtained dried product was kept at a temperature of 700 ° C. for 5 hours while introducing an oxygen stream so that the oxygen concentration became 95% or more. The obtained product is maintained while maintaining the oxygen concentration at 95% or higher by introducing an oxygen stream, and then pressurized to 1 MPa to obtain a product.
Heat treatment was performed at 00 ° C. for 5 hours.

The obtained product was subjected to powder X-ray diffraction using CuKα radiation to find that the composition was Li _1.05 N
i _0.75 Co _0.15 Mn _0.03 Al _0.02 B _0.02 F _0.05 O ₂ , peak intensity ratio I (104) / I (003), FW
HM (003), FWHM (104) and FWHM
HM (003) / FWHM (104) was found to have the values shown in Table 1 below. Further, the Li _1.05 Ni _0.75
Table 2 shows the D50 and specific surface area of the Co _0.15 Mn _0.03 Al _0.02 F _0.05 O _1.95 powder.

The resulting Li _1.05 Ni _0.75 Co _0.15 Mn
_The cylindrical non-aqueous solvent secondary battery shown in FIG. 1 described above was assembled in the same manner as in Example 1 except that _0.03 Al _0.02 F _0.05 O _1.95 powder was used as the positive electrode active material.

Comparative Example 1 Ni _0.83 Co _0.17 (OH) ₂
The cobalt coprecipitated nickel hydroxide powder and aluminum hydroxide represented by the following formula: Al: (Ni + Co) molar ratio of 0.0
It was dispersed in a 1 mol / L aluminum nitrate aqueous solution so as to be 1: 1. A 3 mol / L aqueous sodium hydroxide solution was added dropwise thereto, and the mixture was continuously reacted with stirring at a temperature of 40 to 60 ° C., and the surface was coated with aluminum hydroxide. The obtained product and lithium hydroxide are mixed with L
i: After sufficiently mixing with a ball mill so that the molar ratio of (Ni + Co + Al) becomes 1.02: 1, the air flow is increased to 10% / hr so that the oxygen concentration becomes 10% or more and 15% or less.
While introducing L, heat treatment was performed at a temperature of 800 ° C. for 5 hours.

The obtained product was subjected to powder X-ray diffraction using CuKα radiation to find that the composition was LiNi
_0.82 Co _0.17 Al _0.01 O ₂ , peak intensity ratio I
(104) / I (003), FWHM (003), FW
HM (104) and half width width ratio FWHM (003) / FW
HM (104) was found to be the value shown in Table 1 below. Table 2 below shows the D50 and the specific surface area of the LiNi _0.82 Co _0.17 Al _0.01 O ₂ powder.

The resulting LiNi _0.82 Co _0.17 Al _0.01
A cylindrical non-aqueous solvent secondary battery shown in FIG. 1 was assembled in the same manner as in Example 1 except that O ₂ powder was used as the positive electrode active material.

Comparative Example 2 Ni _0.83 Co _0.17 (OH) ₂
The cobalt coprecipitated nickel hydroxide powder and aluminum hydroxide represented by the following formula: Al: (Ni + Co) molar ratio of 0.0
It was dispersed in a 1 mol / L aluminum nitrate aqueous solution so as to be 1: 1. A 3 mol / L aqueous sodium hydroxide solution was added dropwise thereto, and the mixture was continuously reacted with stirring at a temperature of 40 to 60 ° C., and the surface was coated with aluminum hydroxide. The obtained product and lithium hydroxide are mixed with L
i: After sufficiently mixing with a ball mill so that the molar ratio of (Ni + Co + Al) becomes 1.02: 1, a mixed gas stream of argon and oxygen is supplied at 10 L / hr so that the oxygen concentration becomes 10% or more and 15% or less. While introducing, heat treatment was performed at a temperature of 690 ° C. for 5 hours.

The obtained product was subjected to powder X-ray diffraction using CuKα radiation to find that the composition was LiNi
_0.82 Co _0.17 Al _0.01 O ₂ , peak intensity ratio I
(104) / I (003), FWHM (003), FW
HM (104) and half width width ratio FWHM (003) / FW
HM (104) was found to be the value shown in Table 1 below. Table 2 below shows the D50 and specific surface area of the LiNi _0.82 Co _0.17 Al _0.01 O ₂ powder.

The resulting LiNi _0.82 Co _0.17 Al _0.01
A cylindrical non-aqueous solvent secondary battery shown in FIG. 1 was assembled in the same manner as in Example 1 except that O ₂ powder was used as the positive electrode active material.

Comparative Example 3 Ni _0.83 Co _0.17 (OH) ₂
The cobalt coprecipitated nickel hydroxide powder and aluminum hydroxide represented by the following formula: Al: (Ni + Co) molar ratio of 0.0
It was dispersed in a 1 mol / L aluminum nitrate aqueous solution so as to be 1: 1. A 3 mol / L aqueous sodium hydroxide solution was added dropwise thereto, and the mixture was continuously reacted with stirring at a temperature of 40 to 60 ° C., and the surface was coated with aluminum hydroxide. The obtained product and lithium hydroxide are mixed with L
i: After sufficiently mixing with a ball mill so that the molar ratio of (Ni + Co + Al) becomes 1.02: 1, a mixed gas stream of argon and oxygen is supplied at 10 L / hr so that the oxygen concentration becomes 10% or more and 15% or less. While introducing, heat treatment was performed at a temperature of 650 ° C. for 5 hours.

The obtained product was subjected to powder X-ray diffraction using CuKα radiation to find that the composition was LiNi
_0.82 Co _0.17 Al _0.01 O ₂ , peak intensity ratio I
(104) / I (003), FWHM (003), FW
HM (104) and half width width ratio FWHM (003) / FW
HM (104) was found to be the value shown in Table 1 below. Table 2 below shows the D50 and specific surface area of the LiNi _0.82 Co _0.17 Al _0.01 O ₂ powder.

The resulting LiNi _0.82 Co _0.17 Al _0.01
A cylindrical non-aqueous solvent secondary battery shown in FIG. 1 was assembled in the same manner as in Example 1 except that O ₂ powder was used as the positive electrode active material.

After the secondary batteries of Examples 1 to 13 and Comparative Examples 1 to 3 were charged at a constant current of 400 mA to 4.2 V, the total charging time was 8 hours at a constant voltage of 4.2 V. 400mA, 2000
The discharge capacity when the battery was discharged to 2.7 V at a constant current of 4000 mA was measured. The capacity retention ratio at the time of 2000 mA discharge with respect to the capacity at the time of 400 mA discharge and the capacity retention ratio at the time of 4000 mA discharge with respect to the capacity at the time of 400 mA discharge are calculated, and the results are shown in Table 3 below.

Further, the secondary batteries of Examples 1 to 13 and Comparative Examples 1 to 3 were charged to 4.2 V at a constant current of 400 mA, and further charged at a constant voltage of 4.2 V for a total charging time of 8 hours. After charging, the battery voltage and the temperature of the surface of the battery container were monitored, and the diameter was 2.5 m.
m was passed through the battery container at a speed of 136 cm / sec. The highest temperature at that time was measured and is shown in Table 3 below.

[0123]

[Table 1]

[0124]

[Table 2]

[0125]

[Table 3]

As is clear from Tables 1 to 3, a positive electrode containing a lithium nickel-based composite oxide satisfying the above-mentioned formulas (1) (half width ratio) and (2) (peak intensity ratio) as an active material. Non-aqueous solvent secondary batteries of Examples 1 to 13 comprising
It can be seen that the average discharge voltage is high, the capacity is reduced when discharged with a large current, the heat generation of the battery in the nail penetration test can be suppressed, and the safety is high.

On the other hand, the secondary batteries of Comparative Examples 1 to 3 each provided with a positive electrode containing, as an active material, a lithium-nickel-based composite oxide having a peak intensity ratio satisfying the above range but a half-width ratio out of the range. Has a lower capacity and a lower average discharge voltage when discharged with a large current than the secondary batteries of Examples 1 to 13, and furthermore, in a nail penetration test, the temperature rises to nearly 500 ° C., which may cause rupture or ignition. Understand.

A three-electrode glass cell was assembled using the positive electrodes of the secondary batteries of Examples 4 and 9, and a counter electrode and a reference electrode made of metallic lithium, and subjected to a charge / discharge cycle test (charging; 1 mA / up to 4.2 V). ^3. Perform at constant current of ² cm.
After reaching 2 V, a constant voltage is applied until the current is reduced to 1/10 or less, and discharge is performed at a constant current of 1 mA / cm ² until the voltage reaches 3 V). When the powder was taken out and subjected to powder X-ray diffraction using CuKα radiation, the peak intensity ratio I (104) / I (003) of the positive electrode active material of the secondary battery of Example 4 was 0.29 and the half width was Ratio FWHM (003) / FWHM
(104) was 0.824. On the other hand, for the positive electrode active material of the secondary battery of Example 9, the peak intensity ratio I (10
4) / I (003) is 0.29 and the half width width ratio FWHM
(003) / FWHM (104) was 0.899.

Also, the same evaluation as in the example was performed on the positive electrode active material composed of a composite oxide in which a part of nickel of LiNiO ₂ was replaced with B, Al or Li, and the same effect as in the example was obtained. It was confirmed.

[0130]

As described above in detail, according to the present invention, a non-aqueous solvent secondary battery having a high discharge voltage, excellent large-current charge / discharge characteristics, and improved safety in the event of a battery abnormality is manufactured.
A method can be provided.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view showing an example of a non-aqueous solvent secondary battery according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Container, 2 ... Insulator, 3 ... Electrode group, 4 ... Positive electrode, 5 ... Separator, 6 ... Negative electrode.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-9-298062 (JP, A) JP-A-8-222223 (JP, A) JP-A-9-129231 (JP, A) JP-A-9-129 298061 (JP, A) JP-A-9-270260 (JP, A) JP-A-6-215773 (JP, A) JP-A-6-96769 (JP, A) JP-A-6-96768 (JP, A) JP-A-6-60887 (JP, A) JP-A-10-321224 (JP, A) JP-A-10-208744 (JP, A) JP-A-10-188950 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01M 4/02-4/04 H01M 4/48-4/58 H01M 10/40

Claims (1)

(57) [Claims] 1. A positive electrode comprising a lithium nickel-based composite oxide satisfying the following formulas (1) and (2) as a positive electrode active material, and a negative electrode for inserting and extracting lithium ions. In the method for producing a nonaqueous solvent secondary battery, the positive electrode active material is prepared by dispersing a raw material mixture containing a Ni component and a Li component in a solvent selected from water, an acidic aqueous solution, an alkaline aqueous solution, and an organic solvent, A step of spray-drying the slurry, a step of baking the dried product in an oxidizing atmosphere, and a step of heat-treating in a pressurized oxidizing atmosphere. Manufacturing method of secondary battery. 0.75 ≦ FWHM (003) / FWHM (104) ≦ 0.9 (1) 0.25 ≦ I (104) / I (003) ≦ 0.9 (2) where FWHM (003) in the expression (1). ) Is CuKα
Index hkl of powder X-ray diffraction using X-ray
The half width of the diffraction peak on the (003) plane, FWHM (10
4) is the Miller index h of powder X-ray diffraction using CuKα radiation.
The half width of the diffraction peak on the (104) plane at kl is shown.
In the formula (2), I (003) uses CuKα radiation.
(003) at the Miller index hkl of the powder X-ray diffraction
Integral intensity of diffraction peak on plane, I (104) is CuKα
Index hkl of powder X-ray diffraction using X-ray
It shows the integrated intensity of the diffraction peak on the (104) plane.