JP2003203631A - Positive electrode active material and non-aqueous electrolyte secondary battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a large capacity and improvement in charging and discharging cycle characteristics. <P>SOLUTION: The battery comprises a positive electrode 2 having a positive electrode active material, a negative electrode 3, and a non-aqueous electrolyte, and the positive electrode active material that comprises a mixture of a first lithium transition metal complex oxide containing Ni and Co and made of a laminated structure and a second lithium transition metal complex oxide containing Ni and Mn and made of a laminated structure is used. Thereby, a large capacity and improvement in charging and discharging cycle characteristics are realized. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a positive electrode active material used in a battery and a non-aqueous electrolyte secondary battery using the positive electrode active material.

[0002]

2. Description of the Related Art In recent years, the demand for secondary batteries has increased
Many portable electronic devices such as VTRs, mobile phones, and laptop computers have appeared and are rapidly expanding. Secondary batteries are required to improve energy density as portable power sources as these electronic devices are made smaller and lighter. Among secondary batteries, lithium-ion secondary batteries are expected because they can obtain a larger energy density than lead-based batteries and nickel-cadmium batteries, which are conventional aqueous electrolyte secondary batteries.

A lithium-ion secondary battery is a lithium-cobalt composite oxide having a layered structure as a positive electrode active material,
Lithium manganese composite oxide having a spinel structure,
Lithium-nickel composite oxides have been put to practical use.

The lithium-cobalt composite oxide has the best balance of physical properties such as charge capacity and thermal stability and cost, and is widely used. However, the lithium-cobalt composite oxide is expensive because the amount of mined cobalt is small. Therefore, a cheaper and higher capacity alternative substance is required for the lithium-cobalt composite oxide. The spinel-structured lithium-manganese composite oxide has a lower charge capacity than other cobalt oxides and nickel oxides, and may have a slightly poor high-temperature storage property.

The lithium-nickel composite oxide is expected to be superior to the lithium-cobalt composite oxide in terms of raw material price and supply stability. However, since the lithium-nickel composite oxide has a low crystal structure stability, there are problems that the charge / discharge capacity and energy density are lowered and the charge / discharge cycle characteristics are deteriorated in a high temperature environment.
Therefore, the lithium-nickel composite oxide is excellent in terms of raw material price and supply stability, as described above, if the stability of the crystal structure can be achieved and the decrease in charge / discharge capacity and energy density can be suppressed. Therefore, it is a promising material in the future.

Regarding the stabilization of the crystal structure of the lithium-nickel composite oxide, methods such as solid solution substitution of different elements have been proposed. As the lithium-nickel composite oxide, a method of mixing a lithium-manganese composite oxide having a spinel structure forming a stable crystal structure has been proposed.

[0007]

However, in order to cope with the recent trend toward higher density of electronic devices and the like, speeding up of integrated circuits and the like, and environmental resistance required for portable devices and the like, the solid solution substitution described above is required. It is necessary to form a more stable crystal structure than the stabilization by. In addition, since the spinel structure lithium-manganese composite oxide has a stable crystal structure but a low charge capacity, the high capacity of the lithium-nickel composite oxide is not utilized and the charge / discharge capacity of the positive electrode is reduced. There's a problem.

Therefore, the present invention has been proposed in view of the above conventional circumstances, and improves the charge and discharge capacity and energy density of the positive electrode, and further provides good charging not only at room temperature but also in a high temperature environment. It is an object of the present invention to provide a positive electrode active material capable of obtaining discharge cycle characteristics and a non-aqueous electrolyte battery using the positive electrode active material.

[0009]

A positive electrode active material according to the present invention that achieves the above-mentioned object contains at least Ni and Co, and contains a first positive electrode material having a layered structure and at least Ni and Mn. , And a mixture with a second positive electrode material having a layered structure.

In the positive electrode active material as described above, a first positive electrode material containing at least Ni and Co and having a layered structure and a second positive electrode material containing at least Ni and Mn and having a layered structure are provided. Since they are mixed, the first positive electrode material has a high capacity, and the second positive electrode material has a stable crystal structure, so that the charge and discharge capacity can be increased and the energy density can be improved. Good charge / discharge cycle characteristics can be obtained even under the following conditions.

Further, the non-aqueous electrolyte secondary battery according to the present invention comprises a positive electrode formed by forming a positive electrode mixture layer containing a positive electrode active material on a positive electrode current collector, and a negative electrode active material on a negative electrode current collector. And a non-electrolyte. The positive electrode active material contains a mixture of a first positive electrode material containing at least Ni and Co and having a layered structure, and a second positive electrode material containing at least Ni and Mn and having a layered structure. It is characterized by

In this non-aqueous electrolyte secondary battery, a first positive electrode material containing at least Ni and Co and having a layered structure, and a second positive electrode material containing at least Ni and Mn and having a layered structure are provided. By using the positive electrode active material containing the mixed mixture, the first positive electrode material has a high capacity and the second positive electrode active material has a stable crystal structure, so that the charge and discharge capacity of the positive electrode can be increased. Also, the energy density is improved, and good charge / discharge cycle characteristics can be obtained even in a high temperature environment.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a positive electrode active material and a non-aqueous electrolyte secondary battery using the positive electrode active material, which are shown as embodiments of the present invention, will be described in detail with reference to the drawings. As shown in FIG. 1, in a non-aqueous electrolyte secondary battery 1, an electrode body in which a strip-shaped positive electrode 2 and a strip-shaped negative electrode 3 are wound in close contact with each other via a separator 4 is provided inside a battery can 5. It is filled.

The positive electrode 2 is formed by applying a positive electrode mixture composed of a positive electrode active material, a binder and a conductive agent in a layered manner on a positive electrode current collector. A thermoplastic resin such as polytetrafluoroethylene, polyvinylidene fluoride, or polyethylene is used as the binder. Artificial graphite, carbon black, or the like is used as the conductive agent. A metal foil such as an aluminum foil is used as the positive electrode current collector.

The positive electrode active material contains a mixture of the first positive electrode material and the second positive electrode material. The first positive electrode material has a layered structure and has a chemical formula of LiNiCoMO.
(However, M is a transition metal, or a compound consisting of one or more of the elements of Groups 2, 3, and 4 of the long-period element periodic table, and the range of x, y, and z is , 0.9
0 ≦ x <1.1, 0.05 ≦ y ≦ 0.50, 0.01 ≦ z
≦ 0.10. ) Is a first lithium-transition metal composite oxide. Chemical formula M in LiNiCoMO
Specifically represents an element that can be uniformly dispersed in the crystal of the first lithium-transition metal composite oxide, and particularly preferably Fe, Co, Zn, Al, Sn, Cr, V, Ti,
It is a compound composed of one or more of Mg and Ga.

The second positive electrode material has a layered structure and has a chemical formula of LiNiMnM'O (where M'is a transition metal or an element of Group 2, Group 3 or Group 4 of the long-period element periodic table). A compound composed of one or more kinds, and s, t, u
Are 0.90 ≦ s <1.1, 0.05 ≦ t ≦ 0.50,
0.01 ≦ u ≦ 0.30. ) Is a second lithium-transition metal composite oxide represented by Chemical formula LiNiMnM
M'in'O specifically represents an element capable of being uniformly dispersed in the crystal of the second lithium-transition metal composite oxide, and particularly preferably Fe, Co, Zn, Al, Sn,
It is a compound consisting of one or more of Cr, V, Ti, Mg, and Ga.

The mixing ratio of the first lithium-transition metal composite oxide and the second lithium-transition metal composite oxide is preferably 15% by weight or more and 85% by weight or less based on the whole positive electrode active material. Preferably 30% by weight or more, 7
It should be contained in an amount of 0% by weight or less. The positive electrode active material has a mixing ratio of the first lithium-transition metal composite oxide of 15% by weight.
When the ratio is less than 1, the mixing ratio of the second lithium-transition metal composite oxide exceeds 85%, and the proportion of the low-capacity second lithium-transition composite oxide with respect to the whole positive electrode active material increases, and The high capacity of the lithium-transition metal composite oxide is not utilized and the initial capacity of the positive electrode active material decreases. Also,
When the mixing ratio of the first lithium-transition metal composite oxide exceeds 85% by weight, the mixing ratio of the second lithium-transition composite oxide becomes less than 15%, and the crystal structure of the positive electrode active material becomes unstable. Each time charging and discharging are repeated, the crystal structure is deteriorated, and the charge and discharge cycle capacity retention rate in a high temperature environment is significantly reduced.

Therefore, the positive electrode active material should be mixed such that the mixing ratio of each of the first lithium transition metal composite oxide and the second lithium transition metal composite oxide is 15% by weight or more and 85% by weight or less. The first lithium transition metal composite oxide and the second lithium transition metal composite oxide cancel each other out the change in the charge / discharge capacity and the crystal structure associated with the charge / discharge, so that the change in the crystal structure becomes small. Therefore, the charge / discharge cycle capacity retention rate can be improved.

In the positive electrode active material, the average particle size of the first lithium transition metal composite oxide and the second lithium transition metal composite oxide is preferably 30 μm or less, more preferably 2 μm or more and 30 μm or less. Is. When the average particle diameter of the first lithium-transition metal composite oxide and the second lithium-transition metal composite oxide is less than 2 μm, the positive electrode active material has a large contact area between the positive electrode active material and the electrolyte. Decomposition progresses and the characteristics under high temperature environment deteriorate. On the contrary, when the average particle diameter of the first lithium-transition metal composite oxide and the second lithium-transition metal composite oxide exceeds 30 μm, the positive electrode active material contains the first lithium-transition metal composite oxide and the second lithium-transition metal composite oxide. Mixing with the lithium-transition metal composite oxide becomes insufficient, and the initial capacity decreases and the charge / discharge cycle capacity retention rate deteriorates in a high temperature environment.

Therefore, in the positive electrode active material, the average particle diameter of the first lithium-transition metal composite oxide and the second lithium-transition metal composite oxide is set to 30 μm or less so that the positive electrode active material and the electrolytic solution are separated from each other. The contact area is small and the first
The lithium-transition metal composite oxide described above and the second lithium-transition metal composite oxide are sufficiently mixed, so that the initial capacity can be increased and the charge / discharge cycle capacity retention rate can be improved in a high temperature environment.

Further, in the positive electrode active material, the ratio of Co in the first lithium-transition metal composite oxide and the ratio of Mn in the second lithium-transition metal composite oxide are 0.05 or more and 0.50.
The following is preferable. The positive electrode active material is Co or M
By setting the ratio of n to be less than 0.05, each crystal structure of the first lithium-transition metal composite oxide and the second lithium-transition metal composite oxide becomes unstable, and the positive electrode active material is regenerated every time charging and discharging are repeated. And its charge / discharge cycle characteristics deteriorate. On the contrary, when the ratio of Co and Mn is 0.50 or more, the positive electrode active material forms a crystal structure that causes a decrease in charge / discharge capacity, and thus the charge / discharge capacity is decreased.

Therefore, in the positive electrode active material, the ratio of Co in the first lithium-transition metal composite oxide and the ratio of Mn in the second lithium-transition metal composite oxide are 0.05 or more and 0.5 or more.
By setting it to 0 or less, deterioration of the crystal structure is suppressed and the charge / discharge cycle characteristics are improved. Further, in the positive electrode active material, by setting the ratio of Co and Mn to 0.05 or more and 0.50 or less, a high capacity crystal structure is formed, so that the charge and discharge capacity can be increased.

The first lithium-transition metal composite oxide and the second lithium-transition metal composite oxide are prepared by mixing carbonates such as lithium, nickel, cobalt, manganese, etc. according to their respective compositions and in an air atmosphere or an oxygen atmosphere. At 600-1100
It is obtained by firing in the temperature range of ° C. The starting material is not limited to carbonate, and hydroxide, oxide, nitrate, organic acid salt and the like can be similarly produced. Also,
For the first lithium-transition metal composite oxide and the second lithium-transition metal composite oxide, it is possible to use, as a raw material, a composite hydroxide or a composite carbonate containing lithium, nickel, cobalt, manganese, or the like. .

The positive electrode active material as described above has a high capacity
The mixture of the above lithium transition metal composite oxide and the second lithium transition metal composite oxide forming a stable crystal structure enables the charge and discharge capacity to be increased and the crystal structure to be stabilized. Planned. Therefore, the positive electrode active material can have a high charge / discharge capacity, a high energy density, and an improved charge / discharge cycle capacity retention rate in a high temperature environment. Further, the positive electrode active material includes a mixing ratio of the first lithium-transition metal composite oxide and the second lithium-transition metal composite oxide, an average particle diameter, and Co and the first lithium-transition metal composite oxide. By defining the ratio of Mn in the lithium-transition metal composite oxide of No. 2 or the presence or absence of the additional element in the first lithium-transition metal composite oxide and the second lithium-transition metal composite oxide as described above, A better initial capacity and charge / discharge cycle capacity retention rate can be obtained.

The negative electrode 3 is formed by applying a negative electrode mixture containing a negative electrode active material and a binder onto a negative electrode current collector. As the negative electrode active material, a material capable of electrochemically doping and dedoping lithium at a potential of 2.0 V or less with respect to lithium metal is used. For example, non-graphitizable carbon, artificial graphite, natural graphite, pyrolytic carbons, cokes (pitch cokes, needle cokes, petroleum cokes, etc.), graphites, glassy carbons, organic polymer compound fired bodies (phenolic resin) , A furan resin, etc., which has been carbonized by firing at a suitable temperature), carbon fibers, activated carbon, carbonaceous materials such as carbon blacks.

Further, as the negative electrode active material, a metal capable of forming an alloy with lithium and an alloy compound made of a metal capable of forming an alloy with lithium can be used. As the metal capable of forming an alloy with lithium, a semiconductor element may be included, for example, Mg, B, Al, Ga, In, Si, S.
n, Pb, Sb, Bi, Cd, Ag, Zn, Hf, Z
r and Y. Further, oxides such as ruthenium oxide, molybdenum oxide, tungsten oxide, titanium oxide, and tin oxide, which have a relatively low potential and dope / de-dope lithium ions, and other nitrides can also be used. . A metal such as copper foil is used as the negative electrode current collector. Further, as the conductive agent, the same artificial graphite, carbon black, or the like as the conductive agent used when producing the positive electrode 2 is used.

The manufacturing method of the positive electrode 2 and the negative electrode 3 described above is as follows.
A method of adding a binder, a conductive agent or the like to a positive electrode active material and a negative electrode active material, and applying a solvent, a method of adding a binder or the like to a positive electrode active material and a negative electrode active material, and applying heat, Although a method of producing a molded body electrode by subjecting the negative electrode active material to a single or mixed with a conductive agent, and further a binder, and subjecting the mixture to a treatment such as molding, etc. are not limited thereto.

For example, in the method for producing the positive electrode 2, the positive electrode active material obtained by mixing the first lithium-transition metal composite oxide and the second lithium-transition metal composite oxide is combined with the above-mentioned conductive agent. The agent is mixed at a predetermined ratio to prepare a positive electrode mixture, and this positive electrode mixture is dispersed in an organic solvent such as N-methyl-2-virolidone to form a slurry. Next, the positive electrode mixture in slurry form is uniformly applied onto the positive electrode current collector to form a positive electrode mixture layer, which is dried and then molded to obtain the positive electrode 2.

As a method for producing the negative electrode 3, a negative electrode mixture obtained by mixing the above-mentioned negative electrode active material and a binder in a predetermined ratio is made into a slurry. Next, the negative electrode mixture in slurry form is uniformly applied onto the negative electrode current collector to form a negative electrode mixture layer, which is dried and then molded to obtain the negative electrode 3. In the above-described method for producing the positive electrode 2 and the negative electrode 3, the positive electrode 2 and the negative electrode 3 which have strength by pressure molding with heat applied to the positive electrode active material and the negative electrode active material regardless of the presence or absence of the binder. Can also be produced.

The method for producing the non-aqueous electrolyte secondary battery 1 using the positive electrode 2 and the negative electrode 3 described above includes a method of winding the positive electrode 2 and the negative electrode 3 around the winding core with the separator 4 interposed therebetween. Alternatively, there is a stacking method in which the separator 4 is sandwiched between the positive electrode 2 and the negative electrode 3, and the positive electrode 2 and the negative electrode 3 are stacked.

As the electrolyte, a non-aqueous electrolyte solution in which an electrolyte salt is dissolved in a non-aqueous solvent, a solid electrolyte containing an electrolyte salt, or a non-aqueous electrolyte solution containing a non-aqueous solvent and an electrolyte salt is used as a matrix polymer. Any gel electrolyte that is impregnated into a gel may be used.

The non-aqueous electrolytic solution is prepared by appropriately combining an organic solvent and an electrolyte salt. Any organic solvent can be used as long as it is used in a non-aqueous electrolyte system battery. The organic solvent, for example, propylene carbonate, ethylene carbonate, vinylene carbonate, diethyl carbonate, dimethyl carbonate,
1,2-dimethoxyethane, 1,2-diethoxyethane, γ-butyrolactone, tetravidrofuran, 2-methyltetrahydrofuran, 1,3-dioxolane, 4methyl-1,3dioxolane, diethyl ether, sulfolane, methylsulfolane, acetonitrile , Propionitrile, anisole, acetate, butyrate, propionate and the like. Any electrolyte salt can be used as long as it is used in a non-aqueous electrolyte battery, for example, LiClO, LiAsF, LiPF,
LiBF, LiB (CH), CHSOLi, CFSOL
i, LiCl, LiBr and the like.

As the solid electrolyte, either an inorganic solid electrolyte or a polymer solid electrolyte may be used as long as it has lithium ion conductivity. Examples of the inorganic solid electrolyte include lithium nitride and lithium iodide. The polymer solid electrolyte is composed of a polymer compound containing the electrolyte salt described above. As the polymer compound, a polyethylene oxide, an ether polymer such as a cross-linked product, a polymethacrylate ester system and an acrylate system may be used alone or in the molecule by copolymerization or mixture.

The matrix polymer of gel electrolyte includes
Various organic polymers can be used as long as they absorb the non-aqueous electrolyte and gelate. Matrix macromolecules include
Examples thereof include fluorine-based polymers such as polyvinylidene fluoride and polyvinylidene fluoride-co-hexafluoropropylene, ether-based polymers such as polyethylene oxide and cross-linked products, and polyacrylonitrile. In particular, for the matrix polymer of gel electrolyte,
It is desirable to use a fluoropolymer because of its redox stability. Further, the gel electrolyte matrix is provided with ionic conductivity by containing an electrolyte salt in the non-aqueous electrolyte solution.

In the method for producing the cylindrical non-aqueous electrolyte secondary battery 1, first, the positive electrode 2 and the negative electrode 3 produced as described above are separated by a separator 4 made of a porous polyolefin film.
A large number of windings are carried out through to prepare a spiral type electrode body. Insulating plates 6 are arranged on the upper and lower surfaces of the spirally-wound electrode body and housed in a nickel-plated iron battery can 5. In order to collect the current of the positive electrode 2, one end of the aluminum positive electrode lead 7 is led out from the positive electrode current collector, and the other end is welded to the current blocking thin plate 8 to be electrically connected to the battery lid 9.
Further, in order to collect the current of the negative electrode 3, one end of the nickel negative electrode lead 10 is led out from the negative electrode current collector, and the other end is drawn to the battery can 5.
Weld to the bottom of the.

Next, after pouring the prepared non-aqueous electrolytic solution into the battery can 5 in which the above-mentioned electrode body is incorporated, the battery can 5 is caulked through the insulating sealing gasket 11, so that the battery lid 9 is removed. Fixed In the non-aqueous electrolyte secondary battery 1, a center pin 12 connected to the positive electrode lead 7 and the negative electrode lead 10 was provided, and the pressure inside the non-aqueous electrolyte secondary battery 1 became higher than a predetermined value. In case,
Safety valve 13 for venting the gas inside the non-aqueous electrolyte battery 1,
Also, a PTC (positive temperture coefficient) element 14 for preventing a temperature rise inside the non-aqueous electrolyte secondary battery 1 is provided.

In the non-aqueous electrolyte secondary battery constructed as described above, the positive electrode active material forming the positive electrode 2 forms a stable crystal structure with the high capacity first lithium-transition metal composite oxide. By comprising a mixture of the lithium-transition metal composite oxide of No. 2, the charge / discharge capacity can be increased and the crystal structure can be stabilized. Therefore, the non-aqueous electrolyte secondary battery 1 can have a high charge / discharge capacity and a high energy density, as well as an improved charge / discharge cycle capacity retention rate under normal temperature and high temperature environments.

Further, the shape of the non-aqueous electrolyte secondary battery 1 is not particularly limited, and can be various shapes such as a cylinder type, a square type, a coin type, a button type and a laminate seal type. In this case, it is effective to apply the present invention by a winding method. In that case, the inner diameter of the winding core is made to match the diameter of the portion having the largest curvature among the elliptical cores used at the time of winding for battery production.

[0039]

EXAMPLES Examples and comparative examples of non-aqueous electrolyte secondary batteries using the positive electrode active material to which the present invention is applied will be specifically described below. Here, the shape of the non-aqueous electrolyte secondary battery is a cylindrical non-aqueous electrolyte secondary battery.

Example 1 First, the first lithium-transition metal composite oxide was prepared as follows. Commercially available lithium hydroxide, nickel monoxide, and cobalt oxide were used as raw materials for the first lithium-transition metal composite oxide. The first lithium-transition metal composite oxide was prepared by mixing lithium hydroxide, nickel monoxide, and cobalt oxide in the following composition. In addition, in Example 1, an additive M, which is a transition metal, or an element or a compound composed of a plurality of elements of Group 2, Group 3, and Group 4 of the long-period element periodic table, is used as the first lithium. It was prepared without addition to the transition metal composite oxide. Therefore, the chemical formula of the first lithium-transition metal composite oxide is Li, Ni, C of LiNiCoMO.
The ratio of o and M elements x, 1-yz, y, z is x = 1.0
2, 1-y-z = 0.70, y = 0.30, and z = 0.

Next, the first lithium-transition metal composite oxide is a mixture of lithium hydroxide, nickel monoxide, and cobalt oxide mixed in the above-mentioned composition, fired in an oxygen stream at 800 ° C. for 10 hours, and then pulverized. Obtained. Then, as a result of analyzing the obtained powder with an atomic absorption spectrometer, the first
The lithium-transition metal composite oxide has a chemical formula of LiNiCoO.
It was confirmed that The average particle size of this powder was measured by a laser monochromatography method, and as a result, it was confirmed to be 15 μm. In addition, as a result of X-ray diffraction measurement of this powder, the obtained diffraction pattern is
09-0 of for Diffraction Date (ICDD)
It was confirmed that it had a layered structure similar to that of LiNiO, which is similar to the diffraction pattern of LiNiO in 063.

Next, a second lithium-transition metal composite oxide was prepared as follows. Commercially available lithium hydroxide, nickel monoxide, and manganese dioxide were used as raw materials for the second lithium-transition metal composite oxide. The second lithium-transition metal composite oxide is lithium hydroxide, nickel monoxide,
Manganese dioxide was mixed in the following formulation. In addition, like the first lithium-transition metal composite oxide, the second lithium-transition metal composite oxide contains one of a transition metal and elements of groups 2, 3, and 4 of the long-period element periodic table. Was prepared without adding the additive M'of the element or the compound consisting of plural kinds to the second lithium-transition metal composite oxide. Chemical formula of the second lithium-transition metal composite oxide LiNiMnM ′
O of Li, Ni, Mn, M'element ratio s, 1-tu,
t and u are s = 1.02, 1-t-u = 0.65, t =
It mixed so that it might be set to 0.35 and u = 0.

Next, as the second lithium-transition metal composite oxide, a mixture of lithium hydroxide, nickel monoxide and manganese dioxide in the above-mentioned ratio was fired in an oxygen stream at 800 ° C. for 10 hours. After that, it was obtained by crushing. Then, as a result of analyzing the obtained powder with an atomic absorption spectrometer, the chemical formula Li of the second lithium-transition metal composite oxide was obtained.
It was confirmed that it was represented by NiMnO. In addition, the average particle size of this powder was measured by a laser monochromatography method, and as a result, 1
5 μm was confirmed. The X-ray diffraction measurement of this powder revealed that the obtained diffraction pattern was 09 of ICDD.
It was confirmed that it was similar to the diffraction pattern of LiNiO in -0063 and formed a layered structure similar to LiNiO.

Next, a positive electrode was prepared. First, the above-mentioned first lithium-transition metal composite oxide and the second lithium-transition metal composite oxide were mixed to prepare a positive electrode active material. The positive electrode active material is composed of the first lithium-transition metal composite oxide and the second lithium-transition metal composite oxide.
It was prepared by mixing so that the mixing ratio of the lithium transition metal composite oxide with the first lithium transition metal composite oxide: the second lithium transition metal composite oxide = 50% by weight: 50% by weight. Next, 86 wt% of a positive electrode active material obtained by mixing the first lithium-transition metal composite oxide and the second lithium-transition metal composite oxide, and graphite 10 as a conductive agent.
% By weight, polyvinylidene fluoride as a binder (hereinafter, P
4% by weight of VdF) was mixed and dispersed in an organic solvent N-methyl-2-pyrrolidone (hereinafter, referred to as NMP) to obtain a positive electrode mixture, which was made into a slurry. Next, a slurry-like positive electrode mixture is uniformly applied to both sides of a 20 μm-thick strip-shaped aluminum foil to form a positive electrode mixture layer, which is dried and then compressed with a roller press to obtain a strip-shaped positive electrode. It was

Next, a negative electrode was prepared. For the negative electrode, artificial graphite in powder form was used as the negative electrode active material, and 90% by weight of artificial graphite was added to P.
A negative electrode mixture obtained by mixing 10 wt% of VdF and dispersing it in NMP was made into a slurry. The negative electrode mixture in the form of a slurry was uniformly applied to both surfaces of a copper foil having a thickness of 10 μm to form a negative electrode mixture layer, which was dried and then compressed with a roller press to obtain a negative electrode.

Next, a non-aqueous electrolytic solution was prepared. The non-aqueous electrolyte is a mixed solution of ethylene carbonate and methyl ethyl carbonate at a volume mixing ratio of 1: 1 and a concentration of 1 mol /
It was obtained by dissolving it in a solvent LiPF to have a dm.

Next, a cylindrical non-aqueous electrolyte secondary battery was produced. First, the positive electrode and the negative electrode produced as described above were wound many times with a separator made of a porous polyolefin film interposed therebetween, to produce a spiral type electrode body. Insulating plates were arranged on the upper and lower surfaces of the spirally-wound electrode body and housed in a nickel-plated iron battery can. In order to collect current from the positive electrode, one end of the positive electrode lead made of aluminum is led out from the positive electrode current collector, and the other end is welded to the thin plate for current interruption to electrically connect with the battery lid through the thin sheet for current interruption. Connected Further, in order to collect the current of the negative electrode, one end of the nickel negative electrode lead was led out from the negative electrode current collector, and the other end was welded to the bottom of the battery can.

Next, after pouring the prepared non-aqueous electrolyte into the battery can in which the above-mentioned electrode body is incorporated, the battery can is fixed by caulking the battery can through the insulating sealing gasket. A cylindrical non-aqueous electrolyte secondary battery having an outer diameter of 18 mm and a height of 65 mm was produced. In the non-aqueous electrolyte secondary battery, a center pin connected to the positive electrode lead and the negative electrode lead is provided, and when the pressure inside the non-aqueous electrolyte secondary battery becomes higher than a predetermined value, the non-aqueous electrolyte secondary battery Safety valve for venting gas inside the electrolyte battery, and PTC (positi for preventing temperature rise inside the non-aqueous electrolyte secondary battery)
ve temperturecoefficient) element.

Example 2 In Example 2, aluminum hydroxide was used in addition to lithium hydroxide, nickel monoxide, and cobalt oxide as a raw material for the first lithium-transition metal composite oxide. Mixed in proportions such as. Chemical formula of first lithium-transition metal composite oxide Li, N in LiNiCoAlO
i, Co, Al element ratio x, 1-yz, y, z is x
= 1.02, 1-y-z = 0.70, y = 0.25, z
A first lithium-transition metal composite oxide of LiNiCoAlO was produced in the same manner as in Example 1 except that the mixture was carried out so that the ratio was 0.05. Then, a non-aqueous electrolyte secondary battery was produced in the same manner as in Example 1 except that this first lithium-transition metal composite oxide was used.

Example 3 In Example 3, aluminum hydroxide was used in addition to lithium hydroxide, nickel monoxide, and cobalt oxide as raw materials for the second lithium-transition metal composite oxide, and these raw materials were used as follows. Mixed in proportions such as. Chemical formula of the second lithium-transition metal composite oxide LiNiMnAlO Li, N
The ratio of i, Mn, and Al element s, 1-t-u, t, u is s =
1.02, 1-t-u = 0.65, t = 0.30, u =
A second lithium-transition metal composite oxide of LiNiMnAlO was produced in the same manner as in Example 1 except that the components were mixed and mixed so as to be 0.05. A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 1 except that the second lithium transition metal composite oxide was used.

Example 4 In Example 4, the first lithium-transition metal composite oxide was prepared in the same manner as the first lithium-transition metal composite oxide of Example 2, and the first lithium-transition metal composite oxide of the chemical formula LiNiCoAlO was used. The thing was made. As the second lithium-transition metal composite oxide, a second lithium-transition metal composite oxide having the chemical formula LiNiMnAlO was prepared in the same manner as the second lithium-transition metal composite oxide of Example 3. A nonaqueous electrolyte secondary battery was produced in the same manner as in Example 1 except that the first lithium transition metal composite oxide and the second lithium transition metal composite oxide were used.

Example 5 In Example 5, as the raw material of the first lithium-transition metal composite oxide, lithium hydroxide, nickel monoxide, and cobalt oxide were used, and iron hydroxide was used instead of aluminum hydroxide. , The chemical formula of the first lithium-transition metal composite oxide LiN
iCoFeO ratio of Li, Ni, Co, Fe elements x, 1
-Yz, y, z are x = 1.02, 1-yz = 0.
A first lithium-transition metal composite oxide of LiNiCoFeO was prepared in the same manner as in Example 4 except that 70, y = 0.25 and z = 0.05 were mixed. A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 4 except that this first lithium-transition metal composite oxide was used.

Example 6 In Example 6, as the raw material of the first lithium-transition metal composite oxide, tin oxide was used instead of aluminum hydroxide in addition to lithium hydroxide, nickel monoxide, and cobalt oxide. Chemical formula of the first lithium-transition metal composite oxide LiN
iCoSnO Li, Ni, Co, Sn element ratio x, 1
-Yz, y, z are x = 1.02, 1-yz = 0.
A first lithium-transition metal composite oxide of LiNiCoSnO was prepared in the same manner as in Example 4 except that 70, y = 0.25 and z = 0.05 were mixed. A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 4 except that this first lithium-transition metal composite oxide was used.

Example 7 In Example 7, as a raw material for the first lithium-transition metal composite oxide, in addition to lithium hydroxide, nickel monoxide and cobalt oxide, chromium oxide was used instead of aluminum hydroxide. Chemical formula Li of the first lithium-transition metal composite oxide
NiCoCrO Li, Ni, Cr, Al element ratio x,
1-yz, y and z are x = 1.02, 1-yz =
LiNiCoCr was prepared in the same manner as in Example 4, except that 0.70, y = 0.25 and z = 0.05 were mixed.
A first lithium-transition metal composite oxide of O was prepared. A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 4 except that this first lithium-transition metal composite oxide was used.

Example 8 In Example 8, as the raw material for the first lithium-transition metal composite oxide, vanadium pentoxide was used in place of aluminum hydroxide, in addition to lithium hydroxide, nickel monoxide, and cobalt oxide. , The chemical formula LiNiCoVO of the first lithium-transition metal composite oxide, the ratio x, 1-yz, y, z of Li, Ni, Co and V elements is x = 1.02, 1-yz
= 0.70, y = 0.25, z = 0.05. LiNiCoV
A first lithium-transition metal composite oxide of O was prepared. A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 4 except that this first lithium-transition metal composite oxide was used.

Example 9 In Example 9, as a raw material for the first lithium-transition metal composite oxide, titanium oxide was used in place of aluminum hydroxide in addition to lithium hydroxide, nickel monoxide, and cobalt oxide. Chemical formula Li of the first lithium-transition metal composite oxide
NiCoTiO Li, Ni, Co, Ti element ratio x,
1-yz, y and z are x = 1.02, 1-yz =
LiNiCoTi was prepared in the same manner as in Example 4 except that the components were mixed such that 0.70, y = 0.25 and z = 0.05.
A first lithium-transition metal composite oxide of O was prepared. A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 4 except that this first lithium-transition metal composite oxide was used.

Example 10 In Example 10, as a raw material for the first lithium-transition metal composite oxide, in addition to lithium hydroxide, nickel monoxide, and cobalt oxide, magnesium oxide was used instead of aluminum hydroxide. Chemical formula of the first lithium-transition metal composite oxide LiNiCoMgO of Li, Ni, Co, Mg element ratio x, 1-y-z, y, z, x = 1.02, 1-y
LiNiC was prepared in the same manner as in Example 4 except that the components were mixed such that -z = 0.70, y = 0.25, and z = 0.05.
A first lithium-transition metal composite oxide of oMgO was prepared. A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 4 except that this first lithium-transition metal composite oxide was used.

Example 11 Example 11 uses lithium hydroxide, nickel monoxide, cobalt oxide, and gallium nitrate in place of aluminum hydroxide as a raw material for the first lithium-transition metal composite oxide. The chemical formula LiNiCoGaO of the first lithium-transition metal composite oxide has a ratio x, 1-yz, y, z of Li, Ni, Co, and Ga elements of x = 1.02, 1-yz.
= 0.70, y = 0.25, z = 0.05. LiNiCoG was prepared in the same manner as in Example 4 except that the components were mixed.
A first lithium-transition metal composite oxide of aO was prepared.
A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 4 except that this first lithium-transition metal composite oxide was used.

Example 12 In Example 12, as a raw material for the second lithium-transition metal composite oxide, iron hydroxide was used in place of aluminum hydroxide, in addition to lithium hydroxide, nickel monoxide, and cobalt oxide. The chemical formula Li of the second lithium-transition metal composite oxide
The ratio s of Li, Ni, Mn, and Fe elements of NiMnFeO,
1-t-u, t, and u are s = 1.02, 1-t-u = 0.
LiNiMnF was prepared in the same manner as in Example 4 except that the components were blended and mixed so that 65, t = 0.30 and u = 0.05.
A second lithium-transition metal composite oxide of eO was prepared.
A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 4 except that this first lithium-transition metal composite oxide was used.

Example 13 In Example 13, as the raw material of the second lithium-transition metal composite oxide, in addition to lithium hydroxide, nickel monoxide and cobalt oxide, cobalt oxide was used instead of aluminum hydroxide. Chemical formula of the second lithium-transition metal composite oxide LiNiMnCoO of Li, Ni, Mn, Co element ratio s, 1-t-u, t, u is s = 1.02, 1-t-u =
LiNiM was prepared in the same manner as in Example 4 except that the ingredients were blended so as to be 0.65, t = 0.30 and u = 0.05.
A second lithium-transition metal composite oxide of nCoO was prepared. A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 4 except that this second lithium-transition metal composite oxide was used.

Example 14 In Example 14, as the raw material of the second lithium-transition metal composite oxide, zinc hydroxide was used instead of aluminum hydroxide in addition to lithium hydroxide, nickel monoxide, and cobalt oxide. , The chemical formula L of the second lithium-transition metal composite oxide
The ratio s, 1-t-u, t, u of the Li, Ni, Mn, and Zn elements of iNiMnZnO is s = 1.02, 1-t-u =
LiNiM was prepared in the same manner as in Example 4 except that the ingredients were blended so as to be 0.65, t = 0.30 and u = 0.05.
A second lithium-transition metal composite oxide of nZnO was prepared. A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 4 except that this second lithium-transition metal composite oxide was used.

Example 15 In Example 15, as a raw material of the second lithium-transition metal composite oxide, tin oxide was used in place of aluminum hydroxide, in addition to lithium hydroxide, nickel monoxide, and cobalt oxide. Chemical formula Li of the second lithium-transition metal composite oxide
The ratio s of Li, Ni, Mn, and Sn elements of NiMnSnO,
1-t-u, t, and u are s = 1.02, 1-t-u = 0.
LiNiMnS was prepared in the same manner as in Example 4 except that the ingredients were blended so as to be 65, t = 0.30, u = 0.05.
A second lithium-transition metal composite oxide of nO was prepared.
A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 4 except that this second lithium-transition metal composite oxide was used.

Example 16 In Example 16, in addition to lithium hydroxide, nickel monoxide, and cobalt oxide, chromium oxide was used instead of aluminum hydroxide as a raw material for the second lithium-transition metal composite oxide. Chemical formula L of the second lithium-transition metal composite oxide
The ratio s, 1-t-u, t, u of Li, Ni, Mn, and Cr elements of iNiMnCrO is s = 1.02, 1-t-u =
LiNiM was prepared in the same manner as in Example 1 except that the ingredients were blended and mixed so that 0.65, t = 0.30 and u = 0.05.
A second lithium-transition metal composite oxide of nCrO was prepared. A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 4 except that this second lithium-transition metal composite oxide was used.

Example 17 In Example 17, as the raw material for the second lithium-transition metal composite oxide, vanadium pentoxide was used in place of aluminum hydroxide, in addition to lithium hydroxide, nickel monoxide and cobalt oxide. The chemical formula LiNiMnVO of the second lithium-transition metal composite oxide has a ratio of Li, Ni, Mn, and Sn elements of s, 1-t-u, t, and u is s = 1.02, 1-t-u.
LiNi was used in the same manner as in Example 4 except that the ingredients were blended and mixed so that = 0.65, t = 0.30, u = 0.05.
A second lithium-transition metal composite oxide of MnVO was prepared. A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 4 except that this second lithium-transition metal composite oxide was used.

Example 18 In Example 18, as the raw material of the second lithium-transition metal composite oxide, in addition to lithium hydroxide, nickel monoxide and cobalt oxide, titanium oxide was used instead of aluminum hydroxide. Chemical formula L of the second lithium-transition metal composite oxide
The ratio s, 1-t-u, t, u of the Li, Ni, Mn, and Ti elements of iNiMnTiO is s = 1.02, 1-t-u =
LiNiM was prepared in the same manner as in Example 4 except that the ingredients were blended so as to be 0.65, t = 0.30 and u = 0.05.
A second lithium-transition metal composite oxide of nTiO was prepared. A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 4 except that this second lithium-transition metal composite oxide was used.

Example 19 Example 19 uses lithium hydroxide, nickel monoxide, cobalt oxide, and magnesium oxide instead of aluminum hydroxide as a raw material for the second lithium-transition metal composite oxide. Chemical formula of the second lithium-transition metal composite oxide LiNiMnMgO of Li, Ni, Mn, Mg element ratio s, 1-t-u, t, u is s = 1.02, 1-t-
LiN was prepared in the same manner as in Example 4 except that the ingredients were blended and mixed so that u = 0.65, t = 0.30, and u = 0.05.
A second lithium-transition metal composite oxide of iMnMgO was prepared. A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 4 except that this second lithium-transition metal composite oxide was used.

Example 20 In Example 20, as a raw material for the second lithium-transition metal composite oxide, gallium nitrate was used in place of aluminum hydroxide in addition to lithium hydroxide, nickel monoxide and cobalt oxide. Chemical formula of the second lithium-transition metal composite oxide LiNiMnGaO ratios of Li, Ni, Mn, and Ga elements s, 1-t-u, t, u are s = 1.02, 1-t-u =
LiNiM was prepared in the same manner as in Example 4 except that the ingredients were blended so as to be 0.65, t = 0.30 and u = 0.05.
A second lithium-transition metal composite oxide of nGaO was prepared. A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 4 except that this second lithium-transition metal composite oxide was used.

Example 21 In Example 21, the mixing ratio of the first lithium-transition metal composite oxide and the second lithium-transition metal composite oxide was changed from the first lithium-transition metal composite oxide to the second lithium-transition metal composite oxide. A positive electrode active material was produced in the same manner as in Example 4 except that the compound oxides were mixed at 15% by weight: 85% by weight. A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 4 except that this positive electrode active material was used.

Example 22 In Example 22, the mixing ratio of the first lithium transition metal composite oxide and the second lithium transition metal composite oxide was changed from the first lithium transition metal composite oxide to the second lithium transition metal. A positive electrode active material was produced in the same manner as in Example 4 except that the mixture was such that the composite oxide = 30% by weight: 70% by weight.
A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 4 except that this positive electrode active material was used.

Example 23 In Example 23, the mixing ratio of the first lithium-transition metal composite oxide and the second lithium-transition metal composite oxide was changed from the first lithium-transition metal composite oxide to the second lithium-transition metal composite oxide. A positive electrode active material was produced in the same manner as in Example 4 except that the mixture was such that the composite oxide = 70% by weight: 30% by weight.
A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 4 except that it was used as this positive electrode active material.

Example 24 In Example 24, the mixing ratio of the first lithium-transition metal composite oxide and the second lithium-transition metal composite oxide was changed from the first lithium-transition metal composite oxide to the second lithium-transition metal composite oxide. A positive electrode active material was produced in the same manner as in Example 4 except that the mixture was such that the composite oxide = 85% by weight: 15% by weight.
A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 4 except that this positive electrode active material was used.

Example 25 In Example 25, the first lithium-transition metal composite oxide was
A first lithium-transition metal composite oxide having an average average particle size of 2 μm was produced in the same manner as in Example 4 by changing the production conditions.
A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 4 except that this first lithium-transition metal composite oxide was used.

Example 26 In Example 26, the first lithium-transition metal composite oxide was
The first lithium-transition metal composite oxide having an average average particle size of 8 μm was produced in the same manner as in Example 4 by changing the production conditions.
A nonaqueous electrolyte secondary battery was produced in the same manner as in Example 4 except that this first lithium-transition metal composite oxide was used.

Example 27 In Example 27, the first lithium-transition metal composite oxide was
It was produced in the same manner as in Example 4 except that the first lithium-transition metal composite oxide having an average average particle size of 20 μm was produced by changing the production conditions. A nonaqueous electrolyte secondary battery was produced in the same manner as in Example 4 except for this.

Example 28 In Example 28, the conditions for producing the first lithium-transition metal composite oxide were changed, and the first lithium-transition metal composite oxide having an average average particle diameter of 30 μm was prepared in the same manner as in Example 4. It was made. A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 4 except that this first lithium-transition metal composite oxide was used.

Example 29 In Example 29, the production conditions of the second lithium-transition metal composite oxide in Example 4 were changed, and the second lithium-transition metal composite oxide having an average particle diameter of 2 μm was used. It was prepared in the same manner as the second lithium-transition metal composite oxide. A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 4 except that this second lithium-transition metal composite oxide was used.

Example 30 In Example 30, the production conditions of the second lithium-transition metal composite oxide were changed, and the second lithium-transition metal composite oxide having an average average particle size of 9 μm was used. It was prepared in the same manner as the lithium transition metal composite oxide. A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 4 except that this second lithium-transition metal composite oxide was used.

Example 31 In Example 31, the production conditions of the second lithium-transition metal composite oxide were changed, and the second lithium-transition metal composite oxide having an average particle diameter of 18 μm was used. It was prepared in the same manner as the lithium transition metal composite oxide. A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 4 except that this second lithium-transition metal composite oxide was used.

Example 32 In Example 32, the production conditions of the second lithium-transition metal composite oxide were changed, and the second lithium-transition metal composite oxide having an average particle diameter of 30 μm was used. It was prepared in the same manner as the transition metal composite oxide. A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 4 except that this second lithium-transition metal composite oxide was used.

Example 33 In Example 33, the composition ratio y of cobalt in the first lithium-transition metal composite oxide was changed to 0.05, and Li, Ni, The composition ratio x, 1-yz, y, z of Co and Al elements is x = 1.02,
The first lithium-transition metal composite oxide was prepared by mixing so that 1-y-z = 0.90, y = 0.05, and z = 0.05. A nonaqueous electrolyte secondary battery was produced in the same manner as in Example 4 except for this.

Example 34 In Example 34, the composition ratio y of cobalt in the first lithium-transition metal composite oxide was changed to 0.50, and Li, N
i, Co, Al element composition ratio x, 1-yz, y, z
, X = 1.02, 1-yz = 0.45, y = 0.5
The first lithium-transition metal composite oxide was prepared in the same manner as the first lithium-transition metal composite oxide of Example 4 by mixing so that 0 and z = 0.05. A nonaqueous electrolyte secondary battery was produced in the same manner as in Example 4 except that this first lithium-transition metal composite oxide was used.

Example 35 In Example 35, the composition ratio t of manganese in the second lithium-transition metal composite oxide was changed to 0.05, and Li, N
i, Mn, Al element composition ratios s, 1-t-u, t, u
, S = 1.02, 1-t-u = 0.90, t = 0.0
5, and mixed so that u = 0.05, and a second lithium-transition metal composite oxide was produced in the same manner as the second lithium-transition metal composite oxide of Example 4. A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 4 except that this second lithium-transition metal composite oxide was used.

Example 36 In Example 36, the composition ratio t of manganese in the second lithium-transition metal composite oxide was changed to 0.50, and Li, Ni, The composition ratio of Mn and Al elements is s, 1-t-u, t, and u are s = 1.0.
2, 1-t-u = 0.45, t = 0.50, u = 0.0
Then, the second lithium-transition metal composite oxide was produced in the same manner as in Example 4. A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 4 except that this second lithium-transition metal composite oxide was used.

Comparative Example 1 In Comparative Example 1, lithium hydroxide, nickel monoxide and cobalt oxide were mixed as the raw materials of the first lithium-transition metal composite oxide in the following composition. Chemical formula of the first lithium-transition metal composite oxide Li, Ni, C of LiNiCoMO
The ratio of o and M elements x, 1-yz, y, z is x = 1.0
2, 1-y-z = 0.70, y = 0.30, and z = 0. The first lithium-transition metal composite oxide was represented by the chemical formula LiNiCoO, and was prepared in the same manner as the first lithium-transition metal composite oxide of Example 4. In Comparative Example 1, the positive electrode active material was prepared by using the first lithium-transition metal composite oxide alone without using the second lithium-transition metal composite oxide. A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 4 except that this positive electrode active material was used.

Comparative Example 2 In Comparative Example 2, commercially available lithium hydroxide, nickel monoxide and manganese dioxide were used as raw materials for the second lithium-transition metal composite oxide. As the second lithium-transition metal composite oxide, the first lithium-transition metal composite oxide represented by the chemical formula LiNiMnO was prepared in the same manner as in Example 4.
In Comparative Example 2, the positive electrode active material was prepared by using the second lithium-transition metal composite oxide alone without using the first lithium-transition composite oxide. Example 4 except that this positive electrode active material was used
A non-aqueous electrolyte secondary battery was produced in the same manner as in.

Comparative Example 3 In Comparative Example 3, the mixing ratio of the first lithium-transition metal composite oxide and the second lithium-transition metal composite oxide was changed to the first lithium-transition metal composite oxide: the second lithium-transition metal oxide. A positive electrode active material was produced in the same manner as in Example 4 except that the metal composite oxide was mixed at 10% by weight: 90% by weight. A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 4 except that this positive electrode active material was used.

Comparative Example 4 In Comparative Example 4, the mixing ratio of the first lithium-transition metal composite oxide and the second lithium-transition metal composite oxide was changed to the first lithium-transition metal composite oxide: the second lithium-transition metal oxide. A positive electrode active material was produced in the same manner as in Example 4 except that the metal composite oxide was mixed at 90% by weight: 10% by weight. A nonaqueous electrolyte secondary battery was produced in the same manner as in Example 4 except for the above.

Comparative Example 5 In Comparative Example 5, the first lithium-transition metal composite oxide having an average particle size of 1 μm was prepared in the same manner as in Example 4 by changing the preparation conditions of the first lithium-transition metal composite oxide. did. A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 4 except that this first lithium-transition metal composite oxide was used.

Comparative Example 6 In Comparative Example 6, the first lithium-transition metal composite oxide having an average particle diameter of 40 μm was prepared in the same manner as in Example 4 except that the preparation conditions of the first lithium-transition metal composite oxide were changed. did. A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 4 except that this first lithium-transition metal composite oxide was used.

Comparative Example 7 In Comparative Example 7, a second lithium-transition metal composite oxide having an average particle size of 1 μm was produced in the same manner as in Example 4 by changing the production conditions of the second lithium-transition metal composite oxide. did. A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 4 except that this second lithium-transition metal composite oxide was used.

Comparative Example 8 In Comparative Example 8, a second lithium-transition metal composite oxide having an average particle size of 40 μm was prepared in the same manner as in Example 4 by changing the preparation conditions for the second lithium-transition metal composite oxide. did. A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 4 except that this second lithium-transition metal composite oxide was used.

Comparative Example 9 In Comparative Example 9, the composition ratio y of cobalt in the first lithium-transition metal composite oxide was changed to 0.01, and Li, Ni,
The composition ratios x, 1-yz, y, z of Co and Al elements are
x = 1.02, 1-yz = 0.70, y = 0.01,
Mixing was performed so that z = 0.05, and a first lithium-transition metal composite oxide was produced in the same manner as the first lithium-transition metal composite oxide of Example 4. A nonaqueous electrolyte secondary battery was produced in the same manner as in Example 4 except that this first lithium-transition metal composite oxide was used.

Comparative Example 10 In Comparative Example 10, the composition ratio y of cobalt in the first lithium-transition metal composite oxide was changed to 0.60, and Li, N
i, Co, Al element composition ratio x, 1-yz, y, z
, X = 1.02, 1-yz = 0.70, y = 0.6
The first lithium-transition metal composite oxide was prepared in the same manner as the first lithium-transition metal composite oxide of Example 4 by mixing so that 0 and z = 0.05. A nonaqueous electrolyte secondary battery was produced in the same manner as in Example 4 except that this first lithium-transition metal composite oxide was used.

Comparative Example 11 In Comparative Example 11, the composition ratio t of manganese in the second lithium-transition metal composite oxide was changed to 0.01, and Li, N
i, Mn, Al element composition ratios s, 1-t-u, t, u
, S = 1.02, 1-t-u = 0.70, t = 0.0
Then, the second lithium-transition metal composite oxide was prepared in the same manner as the second lithium-transition metal composite oxide of Example 4 by mixing 1 and u = 0.05. A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 4 except that this second lithium-transition metal composite oxide was used.

Comparative Example 12 In Comparative Example 12, the composition ratio t of manganese in the second lithium-transition metal composite oxide was changed to 0.60, and Li, N
i, Mn, Al element composition ratios s, 1-t-u, t, u
, S = 1.02, 1-t-u = 0.70, t = 0.6
The second lithium-transition metal composite oxide was prepared in the same manner as the second lithium-transition metal composite oxide of Example 4 by mixing so that 0 and u = 0.05. A non-aqueous electrolyte secondary battery was produced in the same manner as in Example 4 except that this second lithium-transition metal composite oxide was used.

Next, regarding the non-aqueous electrolyte secondary batteries of Examples and Comparative Examples produced as described above, the environmental temperature was 23 ° C.,
After charging under the conditions of charging voltage 4.20 V, charging current 1000 mA, charging time 2.5 hours, charging current 1500
The initial capacity was measured by discharging at mA and a final voltage of 2.75V. Further, charging and discharging were repeated under the same conditions, the discharge capacity at the 100th cycle at 23 ° C. was measured, and the capacity retention rate at the 100th cycle with respect to the initial capacity was obtained. Also, set the environmental temperature to 50 ° C and set the other conditions to the environmental temperature of 23 ° C.
In the same manner as in, the capacity retention rate at the 100th cycle was measured when charging and discharging were repeated at 50 ° C.

Hereinafter, the initial capacities in Examples 1 to 20, Comparative Examples 1 and 2, and 10 at 23 ° C.
Table 1 shows the evaluation results of the 0 cycle capacity retention rate and the 100 cycle capacity retention rate at 50 ° C.

[0098]

[Table 1]

From the evaluation results shown in Table 1, in Examples 1 to 20 in which a mixture of the first lithium transition metal composite oxide and the second lithium transition metal composite oxide was used as the positive electrode active material, Compared with Comparative Example 1 in which the first lithium-transition metal composite oxide alone is used to form the positive electrode active material, 2
It can be seen that the 100 cycle capacity retention rate at 3 ° C. and 50 ° C. is improved.

Comparative Example 1 is a case where the first lithium-transition metal composite oxide was used alone as the positive electrode active material, and the transition metal or the elements of Groups 2, 3 and 4 of the periodic table of elements was used. Since the compound consisting of one kind or a plurality of kinds is not added, the crystal structure is unstable, and therefore the crystal structure is deteriorated every time charging and discharging are repeated. Therefore, when the first lithium-transition metal composite oxide is used alone as the positive electrode active material,
The charge / discharge cycle capacity retention rate decreases. In particular, the charge / discharge cycle capacity retention rate under a high temperature environment is significantly lowered due to the deterioration of the crystal structure promoted by the high temperature and the decomposition of the electrolyte.

On the other hand, in Examples 1 to 20, the second lithium-transition metal composite oxide was mixed with the first lithium-transition metal composite oxide to obtain the second lithium-transition metal composite oxide. Since the crystal structure of is stable, the change in the crystal structure of the positive electrode active material due to charge / discharge becomes small, and the deterioration of the crystal structure of the entire positive electrode active material due to charge / discharge is suppressed. Therefore, the positive electrode active material should be 23 ℃ and 50 ℃.
The 100-cycle capacity retention ratio in 100 is improved.

From the evaluation results shown in Table 1, Example 1
It is understood that in Example 20, the initial capacity was increased as compared with Comparative Example 2 in which the second lithium-transition metal composite oxide alone was used to form the positive electrode active material.

In Comparative Example 2, the second lithium-transition metal composite oxide was used alone as the positive electrode active material, and among the transition metals or the elements of Groups 2, 3 and 4 of the periodic table of elements. Since the compound of one kind or a plurality of kinds is not added, the second lithium-transition metal composite oxide has a low capacity, so that the initial capacity is lowered.

On the other hand, in Examples 1 to 20, by mixing the first lithium-transition metal composite oxide in addition to the second lithium-transition metal composite oxide, the first lithium-transition metal composite oxide was mixed. Has a high capacity, the initial capacity of the entire positive electrode active material is improved.

From the above, a mixture of the first lithium-transition metal composite oxide and the second lithium-transition metal composite oxide is used as the positive electrode active material when producing the non-aqueous electrolyte secondary battery. By increasing the initial capacity,
It is clear that it is effective for increasing the energy density and improving the charge / discharge cycle capacity retention rate. In addition, as in Example 1, the first lithium-transition metal composite oxide and the second lithium-transition metal composite oxide are selected from the group consisting of transition metals or groups 2, 3, and 4 of the periodic table of the elements. Even without adding an element, the initial capacity can be increased and the charge / discharge cycle capacity retention rate can be improved.

Next, Example 1, Example 21 to Example 2
4, initial capacity in Comparative Example 3 and Comparative Example 4, 100 cycle capacity retention rate at 23 ° C. and 1 at 50 ° C.
Table 2 shows the evaluation results of the 00 cycle capacity retention rate. The additive M and the additive M ′ added to the first lithium-transition metal composite oxide and the second lithium-transition metal composite oxide are the same as Example 1, Example 21 to Example 24, Comparative Example 3 and Comparative Example 4 All are Al.

[0107]

[Table 2]

From the evaluation results shown in Table 2, the mixing ratio of the first lithium transition metal composite oxide and the second lithium transition metal composite oxide was 15% by weight or more and 85% by weight or less based on the whole positive electrode active material. In Example 1, Example 21 to Example 24, in which the first lithium-transition metal composite oxide is 1
It can be seen that the initial capacity is increased as compared with Comparative Example 3 in which 0% and the second lithium-transition metal composite oxide are 90%.

In Comparative Example 3, the first positive electrode active material was added to the first positive active material as a whole.
The mixture of 10% by weight of the lithium transition metal composite oxide and 90% by weight of the second lithium transition metal composite oxide is used for the positive electrode active material, whereby a low capacity second lithium transition metal composite oxide is obtained. Since it occupies most of the positive electrode active material, the initial capacity is remarkably reduced as compared with Examples 1 and 21 to 24.

On the other hand, in Example 1 and Examples 21 to 24, the mixing ratio of the second lithium-transition metal composite oxide was 15 wt% or more and 85 wt% with respect to the whole positive electrode active material.
By mixing in the following range, the high-capacity first lithium-transition metal composite oxide is contained in an appropriate weight% with respect to the entire positive electrode active material, so that the initial capacity can be increased. . In addition, in Example 1 and Examples 21 to 24, the initial capacity was increased as the mixing ratio of the first lithium-transition metal composite oxide increased.

Further, from the evaluation results shown in Table 2, in Example 1 and Examples 21 to 24, the first lithium transition metal composite oxide was 90% and the second lithium transition metal composite oxide was 10%. 23 ° C. and 5
It can be seen that the 100 cycle capacity retention rate at 0 ° C. is improved.

In Comparative Example 4, the first positive electrode active material was added to the first positive active material.
The first lithium-transition metal composite oxide having an unstable crystal structure is obtained by using a mixture of 90% of the second lithium-transition metal composite oxide and 10% of the second lithium-transition metal composite oxide as a positive electrode active material. Occupies most of the positive electrode active material, the deterioration of the crystal structure is promoted every time charge and discharge are repeated, and the charge and discharge cycle capacity retention rate decreases. In particular, in the positive electrode active material, the deterioration of the crystal structure is promoted in a high temperature environment, and the 100 cycle capacity retention ratio at 50 ° C. is remarkably reduced due to the deterioration of the electrolyte.

On the other hand, in Examples 1 and 21 to 24, the mixing ratio of the first lithium-transition metal composite oxide to the whole positive electrode active material was 15% by weight or more and 85% by weight.
By mixing in the following range and mixing at an appropriate weight% with respect to the entire positive electrode active material, the change in the crystal structure of the positive electrode active material due to charge / discharge is suppressed, and the charge / discharge cycle capacity retention rate is improved. ing.

From the above, when the non-aqueous electrolyte secondary battery is manufactured, the positive electrode active material has a mixing ratio of the first lithium-transition metal composite oxide of 15% by weight or more and 85% to the whole.
It can be seen that by mixing in the range of not more than wt%, the initial capacity can be increased and the charge / discharge cycle capacity retention rate can be improved.

Next, Example 1, Example 27 to Example 3
2, and the initial capacity in Comparative Examples 5 to 8, 23
Table 3 shows the evaluation results of the 100 cycle capacity retention rate at 50 ° C and the 100 cycle capacity retention rate at 50 ° C.
The mixing ratio of the first lithium transition metal composite oxide and the second lithium transition metal composite oxide is as follows: first lithium transition metal composite oxide: second lithium transition metal composite oxide = 50 wt%. : 50% by weight.

[0116]

[Table 3]

From the evaluation results of Table 3, Example 1 and Example 1 in which the average particle diameter of each of the first lithium transition metal composite oxide and the second lithium transition metal composite oxide was set in the range of 2 μm to 30 μm Examples 27 to 32 and Comparative Examples 5 to 8 in which one of the first lithium transition metal composite oxide and the second lithium transition metal composite oxide was 1 μm or 40 μm and the other was 15 μm. It can be seen from the comparison between the above results that the capacity retention rate at 50 ° C. for 100 cycles is improved.

In Comparative Examples 5 to 8, if the average particle size of either the first lithium-transition metal composite oxide or the second lithium-transition metal composite oxide is less than 2 μm and the other is 15 μm, the positive electrode Since the contact area between the active material and the electrolytic solution becomes too large, the decomposition of the electrolyte progresses, and as compared with Example 1 and Example 27 to Example 32, it is 50 ° C.
The cycle capacity retention rate in the is decreasing. On the other hand, if the average particle size exceeds 30 μm, the mixing of the first lithium transition metal composite oxide and the second lithium transition metal composite oxide becomes insufficient and the cycle capacity retention rate decreases, especially at 50 ° C. The cycle capacity retention rate is decreasing.

On the other hand, Example 1, Example 25 and Example 2
In No. 8, a mixture obtained by mixing the first lithium-transition metal composite oxide with an average particle size of 2 μm or more and 30 μm or less and the second lithium-transition metal composite oxide having an average particle size of 15 μm was used as a positive electrode. By using it as the active material, the contact area between the positive electrode active material and the electrolytic solution is reduced, and the first lithium transition metal composite oxide and the second lithium transition metal composite oxide are sufficiently mixed. Therefore, in Examples 1 and 25 to 28, the 100 cycle capacity retention ratio at 50 ° C. is improved as compared with Comparative Examples 5 to 8.

From the above, when the non-aqueous electrolyte secondary battery is manufactured, the positive electrode active material has an average particle size of 2 μm of the first lithium transition metal composite oxide and the second lithium transition metal composite oxide. Above, by setting the range of 30μm or less,
The 100 cycle capacity retention rate at 50 ° C. is improved.

Next, Example 1, Example 33 to Example 3
6, and the initial capacities in Comparative Examples 9 to 12, 2
Table 4 shows the evaluation results of the 100 cycle capacity retention rate at 3 ° C and the 100 cycle capacity retention rate at 50 ° C. The mixing ratio of the first lithium-transition metal composite oxide and the second lithium-transition metal composite oxide is 50% by weight of the first lithium-transition metal composite oxide to the second lithium-transition metal composite oxide. 50% by weight.

[0122]

[Table 4]

From the evaluation results in Table 4, the ratio y of Co in the first lithium-transition metal composite oxide (LiNiCoMO) was y.
And a second lithium-transition metal composite oxide (LiNiMn
The range of the ratio t of Mn in (MO) is 0.05 or more, 0.5
Example 1 and Examples 33 to 36 in which the value is 0 or less
Is compared with Comparative Examples 9 to 11 in which the ratio y or t is set to 0.05 or less and one is set to 0.05 or more and 0.50 or less. It can be seen that the improvement is being made.

In Comparative Example 9, the ratio y of Co in the lithium-transition metal composite oxide of 1 was set to 0.01, and Comparative Example 12
Is the ratio Mn of Mn in the second lithium-transition metal composite oxide.
Is 0.01. As described above, in Comparative Examples 9 to 11, the ratio y of Co in the first lithium-transition metal composite oxide was 0.01, or the ratio t of Mn in the second lithium-transition metal composite oxide was 0. By setting the ratio to 0.01, each crystal structure becomes unstable and the crystal structure of the positive electrode active material deteriorates every time charging and discharging are repeated, and the charge-discharge cycle capacity retention rate decreases. Further, in particular, in the positive electrode active material, the deterioration of the crystal structure is promoted in a high temperature environment, and the 100 cycle capacity retention rate at 50 ° C. is remarkably reduced.

On the other hand, in Examples 1 and 33 to 36, Co in the first lithium-transition metal composite oxide was used.
Ratio y and the second lithium-transition metal composite oxide (Li
By setting the range of the ratio Mn of Mn in NiMnMO) to be 0.05 or more and 0.50 or less, each crystal structure in the first lithium-transition metal composite oxide and the second lithium-transition metal composite oxide is An excellent charge / discharge cycle capacity retention rate can be stably obtained even in a high temperature environment.

From the evaluation results shown in Table 4, Example 1
In Examples 33 to 36, the ratio y of Co in the first lithium-transition metal composite oxide (LiNiCoMO) is y.
Alternatively, the second lithium transition metal composite oxide (LiNiM
(nMO) has a higher initial capacity than Comparative Examples 10 to 12 in which the range of the ratio M of Mn is more than 0.50 and one is 0.05 or more and less than 0.50. I understand that.

Comparative Example 10 is a first lithium transition metal composite oxide having a Co ratio y of 0.60, and Comparative Example 12 is a second lithium transition metal composite oxide having a Mn ratio t of 0.60. This is the case when a metal composite oxide is used. Comparative Example 1
0 to Comparative Example 12, the ratio of Co and Mn was set to 0.
By setting it to be larger than 5, the capacity of the whole positive electrode active material was decreased, and thus the initial capacity was decreased.

On the other hand, in Examples 1 and 33 to 36, the ratio y of Co in the first lithium-transition metal composite oxide and Mn in the second lithium-transition metal composite oxide were determined.
By setting the range of the ratio t of 0.05 to 0.50, the crystal structure was stabilized and the initial capacity was increased.

As described above, when the non-aqueous electrolyte secondary battery is manufactured, C in the first lithium-transition metal composite oxide is used.
By setting the ratio of O and Mn in the second lithium-transition metal composite oxide in the range of 0.05 or more and 0.50 or less, the initial capacity can be increased and the charge / discharge cycle characteristics can be improved. I understood.

[0130]

As described above in detail, according to the present invention, a positive electrode active material containing a mixture of a first positive electrode material having a high capacity and a second positive electrode material having a stable crystal structure. By using a substance, the initial capacity can be increased and the energy density can be improved, and a non-aqueous electrolyte secondary battery having a good charge / discharge cycle capacity retention rate not only at room temperature but also in a high temperature environment can be obtained. You can

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a non-aqueous electrolyte secondary battery according to the present invention.

[Explanation of symbols]

1 non-aqueous electrolyte secondary battery, 2 positive electrode, 3 negative electrode, 4 separator, 5 battery can, 6 insulating plate, 7 positive electrode lead,
8 current cut thin plate, 9 battery cover, 10 negative electrode lead,
11 Insulation sealing gasket, 12 Center pin, 13
Safety valve, 14PTC element

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4G048 AA04 AC06                 5H029 AJ03 AJ05 AK03 AK18 AL01                       AL02 AL06 AL07 AL08 AL12                       AM03 AM04 AM05 AM07 AM12                       AM16 BJ02 BJ14 CJ08 DJ16                       DJ17 HJ01 HJ05                 5H050 AA07 AA08 BA17 CA08 CA09                       CA29 CB01 CB02 CB07 CB08                       CB09 CB12 FA17 FA19 GA10                       HA01 HA02 HA05

Claims (8)

[Claims] 1. A mixture of a first positive electrode material containing at least Ni and Co and having a layered structure, and a second positive electrode material containing at least Ni and Mn and having a layered structure. Positive electrode active material. 2. The first positive electrode material is a first lithium-transition metal composite oxide represented by formula 1, and the second positive-electrode material is a second lithium transition metal composite oxide represented by formula 2. Be an oxide [Chemical formula 1] [Chemical 2] The positive electrode active material according to claim 1, wherein 3. The mixing ratio of each of the first positive electrode material and the second positive electrode material is 1 with respect to the entire positive electrode active material.
The positive electrode active material according to claim 1, which is in a range of 5% by weight or more and 85% by weight or less. 4. The positive electrode active material according to claim 1, wherein the average particle size of each of the first positive electrode material and the second positive electrode material is in the range of 2 μm or more and 30 μm or less. 5. A positive electrode having a positive electrode mixture layer containing a positive electrode active material formed on a positive electrode current collector, and a negative electrode mixture layer containing a negative electrode active material formed on a negative electrode current collector. A negative electrode and a non-aqueous electrolyte, wherein the positive electrode active material contains at least Ni and Co,
A non-aqueous electrolyte secondary battery comprising a mixture of a first positive electrode material having a layered structure and a second positive electrode material containing at least Ni and Mn and having a layered structure. 6. The first positive electrode material is a first lithium-transition metal composite oxide represented by formula 1, and the second positive electrode material is a second lithium-transition metal composite oxide represented by formula 2. Being an oxide [Chemical formula 3] [Chemical 4] The non-aqueous electrolyte secondary battery according to claim 5. 7. The mixing ratio of each of the first positive electrode material and the second positive electrode material is 1 with respect to the entire positive electrode active material.
The non-aqueous electrolyte secondary battery according to claim 5, which is in a range of 5% by weight or more and 85% by weight or less. 8. The non-aqueous electrolyte secondary according to claim 5, wherein the average particle size of each of the first positive electrode material and the second positive electrode material is in the range of 2 μm or more and 30 μm or less. battery.