JP2003297340A - Positive electrode for non-aqueous electrolyte secondary battery and secondary battery using such positive electrode - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a positive electrode having a high energy density, an excellent heavy load characteristic, and an excellent low-temperature characteristic and provide a non-aqueous electrolyte secondary battery using such a positive electrode. <P>SOLUTION: The positive electrode 3 includes positive electrode active material layers 15 and 16 located on the sides of a positive electrode current collector 13 and containing LiXNi<SB>1-</SB>Y<SB>-</SB>ZCoYMZO<SB>2</SB>provided that the conditions 0.95≤x≤1.25, 0.01≤y≤0.50, and 0.01≤z≤0.40 should be met (where M is one or more metals selected among Ti, Cr, Fe, Mn, Zn, Al, Mo, W), wherein the thickness T<SB>1</SB>of the positive electrode current collector 13 and the total (T<SB>2</SB>+T<SB>3</SB>) of the thicknesses of the positive electrode active material layers 15 and 16 should meet the conditions 2.5≤(T<SB>2</SB>+T<SB>3</SB>)/T<SB>1</SB>and (T<SB>2</SB>+T<SB>3</SB>)≤250 μm. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a positive electrode for a non-aqueous electrolyte secondary battery and a non-aqueous electrolyte secondary battery using the same.

[0002]

2. Description of the Related Art Non-aqueous electrolyte secondary batteries have higher energy density and longer life than conventional batteries, and are used as power sources for, for example, mobile phones and notebook personal computers.

In such a non-aqueous electrolyte secondary battery, for example, a carbonaceous material is used as the negative electrode active material, a lithium transition metal composite oxide is used as the positive electrode active material, and a non-aqueous electrolyte having a lithium salt as a supporting salt is used as the electrolyte. However, in particular, the positive electrode active material is an important constituent element that determines performance such as discharge capacity, discharge voltage, cycle life characteristics, and safety of the non-aqueous electrolyte secondary battery.

As a positive electrode active material for a non-aqueous electrolyte secondary battery, a lithium manganese composite compound using manganese, which has a large amount of reserves and is inexpensive as a raw material, has been actively studied. However, since the lithium-manganese composite compound is an active material having a spinel structure, it has a low lithium diffusion coefficient, and cannot be said to have sufficient heavy load characteristics and low temperature characteristics. Also, the energy density is low.

On the other hand, currently available small non-aqueous electrolyte secondary batteries use lithium cobalt oxide having a layered structure as a positive electrode active material. Lithium cobalt oxide has a remarkably large diffusion coefficient of lithium ions of about 10 to 100 times that of an active material having a spinel structure, and has a high energy density, but there is a problem that cobalt as a raw material is a rare metal and its price is unstable. .

[0006]

The present invention has been completed based on the above circumstances, and is a positive electrode having low cost, high energy density, excellent heavy load characteristics, and excellent low temperature characteristics. And a non-aqueous electrolyte secondary battery using the same.

[0007]

Means for Solving the Problems
Positive electrode capable of solving the problems, and non-aqueous electrolyte using the same
As a result of intensive research to develop a secondary battery,
A layer that is cheaper than Baltic and similar to cobalt
Nickel capable of forming crystalline compounds should be used in combination with cobalt.
And That is, on both sides of the positive electrode current collector, Li_XNi
_1-YZCo_YM_Z O₂(0.95 ≤ x ≤ 1.25, 0.
01 ≦ y ≦ 0.50, 0.01 ≦ z ≦ 0.40, and M is
Ti, Cr, Fe, Mn, Zn, Al, Mo, W
Positive electrode active material containing at least one metal selected from
In the positive electrode on which the material layer is arranged, the thickness T1 of the positive electrode current collector
And the total thickness (T2 + T3) of the positive electrode active material layer,
2.5 ≦ (T2 + T3) / T1, and (T2 + T3) ≦
Non-aqueous electrolyte characterized by satisfying a relationship of 250 μm
By using the positive electrode for a secondary battery, the cost is easy and the cost is high.
Energy density, excellent heavy load characteristics, and excellent low temperature characteristics
To find a non-aqueous electrolyte secondary battery with high performance
Then, the present invention has been completed.

That is, in the invention of claim 1, Li _X Ni _{1 -YZ} Co _Y M _Z O ₂ (0.95 ≤ x is provided on both sides of the positive electrode current collector.
≦ 1.25, 0.01 ≦ y ≦ 0.50, 0.01 ≦ z ≦
0.40, M is Ti, Cr, Fe, Mn, Zn, A
In a positive electrode in which a positive electrode active material layer containing at least one metal selected from the group consisting of 1, Mo and W) is arranged, the positive electrode active material layer having a thickness T1 and a thickness of the positive electrode active material layer Total (T2 + T3) is 2.5 ≦ (T2 + T3) / T
The positive electrode for a non-aqueous electrolyte secondary battery was characterized by satisfying the relationship of 1 and (T2 + T3) ≦ 250 μm.

According to a second aspect of the present invention, the positive electrode current collector is provided on both sides,
Li _X Ni _1-YZ Co _Y M _Z O ₂ (0.95 ≦ x ≦ 1.
25, 0.01 ≦ y ≦ 0.50, 0.01 ≦ z ≦ 0.4
0, M are Ti, Cr, Fe, Mn, Zn, Al, M
a positive electrode having a positive electrode active material layer containing at least one or more metals selected from o and W), a negative electrode having a negative electrode active material layer on a negative electrode current collector, and a non-aqueous electrolyte. In the water electrolyte secondary battery, the thickness T1 of the positive electrode current collector,
The total thickness (T2 + T3) of the positive electrode active material layer is 2.
5 ≦ (T2 + T3) / T1, and (T2 + T3) ≦ 25
The non-aqueous electrolyte secondary battery was characterized by satisfying the relationship of 0 μm.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic cross-sectional view of a prismatic non-aqueous electrolyte secondary battery 1 according to an embodiment of the present invention. The prismatic non-aqueous electrolyte secondary battery 1 includes a positive electrode 3 and
A flat wound electrode group 2 in which a negative electrode 4 is wound via a separator 5 and a non-aqueous electrolytic solution (not shown) containing an electrolyte salt are housed in a battery case 6.

A battery lid 7 provided with a safety valve 8 is attached to the battery case 6 by laser welding, the positive electrode terminal 10 is connected to the positive electrode 3 via a positive electrode lead 11, and the negative electrode 4 is an inner wall of the battery case 6. Is electrically connected by contact with.

The positive electrode 3 is, for example, as shown in FIG.
For example, aluminum, titanium, or stainless steel positive electrode collection
A substance that absorbs and releases lithium ions on both sides of the electric body 13
A positive electrode active material layer 15 composed of a positive electrode mixture containing
16 is provided. This positive electrode active material layer 1
5 and 16 are Li as a positive electrode active material._XNi_1-YZCo
_YM_ZO₂(0.95 ≤ x ≤ 1.25, 0.01 ≤ y ≤
0.50, 0.01 ≦ z ≦ 0.40, M is Ti, C
Selected from r, Fe, Mn, Zn, Al, Mo, W
At least one metal). Like this
A layered structure is formed in the titanium nickel cobalt composite oxide.
ing. Lithium ion is a two-dimensional diffusion of lithium alone
It is movable through the layers, and this feature makes it a layered structure type
Titanium-nickel-cobalt composite oxide is used for non-aqueous electrolyte batteries.
It can be used as positive electrode active material, especially non-aqueous electrolyte lithium
It is suitable as a positive electrode active material for secondary batteries.

Such a lithium nickel cobalt composite oxide can be prepared by a known method, for example, lithium carbonate, lithium nitrate, lithium oxide, lithium hydroxide, nickel carbonate or nickel carbonate. Nitrate, nickel oxide, nickel hydroxide and cobalt carbonate, cobalt nitrate, cobalt oxide, cobalt hydroxide are pulverized and mixed in a predetermined ratio, for example in an oxygen-containing atmosphere It can be obtained by firing at 600 to 900 ° C.

The positive electrode 3 is manufactured as follows, for example. A positive electrode active material is mixed with a conductive agent such as graphite or carbon black and a binder such as polyvinylidene fluoride to prepare a positive electrode mixture. Then, this positive electrode mixture is dispersed in a solvent such as N-methylpyrrolidone to obtain a slurry. This is applied to both surfaces of the positive electrode current collector 13, dried, and then compressed and smoothed by a roll press or the like to manufacture the positive electrode 3.

Here, the thickness of the positive electrode current collector 13 of the positive electrode 3 is T1, and the thicknesses of the positive electrode active material layers 15 and 16 are respectively
Let T2 and T3. In this embodiment, the total thickness T1 of the positive electrode current collector 13 and the thickness of the positive electrode active material layer (T2 + T3).
And 2.5 ≦ (T2 + T3) / T1, and (T2 + T
3) The relationship of ≦ 250 μm is satisfied.

The value of (T2 + T3) / T1 is 2.5 ≦
(T2 + T3) / T1 is required, and preferably
4.0 ≦ (T2 + T3) / T1, especially 5.0 ≦ (T2 +
It is preferably T3) / T1. (T2 + T3) /
This is because when the value of T1 is less than 2.5, the proportion of the positive electrode current collector 13 in the positive electrode 3 increases and the energy density decreases.

Further, it is necessary that (T2 + T3) ≦ 250 μm, preferably (T2 + T3) ≦ 200 μm,
It is particularly preferable that (T2 + T3) ≦ 150 μm. As described above, when the thickness is 250 μm or less, it is considered that the discharge capacity at the time of heavy load can be improved for the following reason.

In the non-aqueous electrolyte secondary battery, lithium ions move from the negative electrode 4 to the positive electrode 3 via the electrolyte during discharging. Then, the lithium that has moved to the positive electrode 3 is
It diffuses from the surface of the positive electrode 3 toward the inside.

Here, the lithium-nickel-cobalt composite oxide is a layered compound similar to the lithium-cobalt composite oxide conventionally used in non-aqueous electrolyte secondary batteries, but nickel having different atomic radii in the same crystal. And lithium are mixed, the diffusion rate of lithium ions is slower than that of the lithium-cobalt composite oxide. Therefore, when the active material layers 15 and 16 are thicker than 250 μm, lithium ions are transferred from the positive electrode active material layers 15 and 16 on the surface of the positive electrode 3 to the positive electrode active material layers 15 and 16 inside the positive electrode 3, that is, in the vicinity of the positive electrode current collector 13. It takes a very long time to reach the positive electrode active material layers 15 and 16.

As a result, the positive electrode active material layers 15 and 16 in the vicinity of the positive electrode current collector 13 cannot be effectively used, and the discharge capacity under heavy load is reduced.

Therefore, in this embodiment, (T2 + T3)
It is assumed that ≦ 250 μm, and the lithium ions rapidly move to the positive electrode active material layers 15 and 16 near the positive electrode current collector 13, and the positive electrode active material layers 15 and 1 near the positive electrode current collector 13.
By effectively using No. 6, the discharge capacity under heavy load is improved.

When (T2 + T3) ≦ 250 μm, the discharge capacity can be secured even at low temperature where the diffusion rate of lithium ions in the lithium nickel cobalt composite oxide is slower.

Thus, the thickness T1 of the positive electrode current collector 13
Total thickness of positive electrode active material layers 15 and 16 (T2 + T3)
2.5 ≦ (T2 + T3) / T1, and (T2 + T
3) It is necessary to satisfy the relationship of ≦ 250 μm.

As shown in FIG. 3, the negative electrode 4 is made of, for example, a negative electrode current collector made of copper, nickel, titanium, or stainless steel, and is composed of a negative electrode mixture containing a substance that absorbs and releases lithium ions on both sides. The structure has an active material layer. Note that the negative electrode active material layer may be provided not only on both surfaces but also on one surface.

The negative electrode 4 is manufactured, for example, as follows. The negative electrode active material is mixed with a binder such as polyvinylidene fluoride to prepare a negative electrode mixture. Then, this negative electrode mixture is dispersed in a solvent such as N-methylpyrrolidone to form a slurry. This is applied on both surfaces of the negative electrode current collector, dried, and then compressed and smoothed by a roll press or the like to manufacture the negative electrode 4.

The negative electrode active material is not particularly limited, and examples thereof include known cokes, glassy carbons, graphites, non-graphitizable carbons, pyrolytic carbons, carbonaceous materials such as carbon fibers, or metals. Lithium, lithium alloy, polyacene, or tin oxide glass, lithium / titanium composite oxide, iron oxide, ruthenium oxide, molybdenum oxide, tungsten oxide, titanium oxide, tin oxide, metal oxides such as tin oxide, etc. alone. Alternatively, two or more kinds may be mixed and used, but it is particularly preferable to use a carbonaceous material because of its high safety.

The separator 5 is not particularly limited,
For example, a known woven fabric, non-woven fabric, synthetic resin microporous film, or the like can be used, and a synthetic resin microporous film can be preferably used. Among them, a polyolefin-based microporous film such as a polyethylene and polypropylene microporous film or a composite microporous film thereof is preferably used in terms of thickness, film strength, film resistance and the like.

Further, by using a solid electrolyte such as a polymer solid electrolyte, it can also serve as a separator.
In this case, the solid polymer electrolyte may further contain an electrolytic solution, for example, by using a porous solid polymer electrolyte membrane as the solid polymer electrolyte.

As the non-aqueous electrolyte of the present invention, either a non-aqueous electrolytic solution or a solid electrolyte can be used. When the non-aqueous electrolyte is used, it is not particularly limited, and for example, a mixed solvent of ethylene carbonate and ethyl methyl carbonate or a mixed solvent of ethylene carbonate and dimethyl carbonate is used. In the mixed solvent, propylene carbonate, butylene carbonate, vinylene carbonate, trifluoropropylene carbonate, γ-butyrolactone, 2-methyl-γ-butyl lactone, acetyl-γ-butyrolactone, γ-valerolactone, sulfolane, 1,2-dimethoxy. Ethane, 1,2-diethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyl-1,3-dioxolane, methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate , Dipropyl carbonate, methyl propyl carbonate, ethyl isopropyl carbonate, dibutyl carbonate, etc. may be used alone or in admixture of two or more.

The electrolyte salt as a solute of the non-aqueous electrolyte is not particularly limited, and may be, for example, LiClO ₄ , LiAsF ₆ , Li.
PF ₆ , LiBF ₄ , LiCF ₃ SO ₃ , LiCF ₃ C
F ₂ SO ₃ , LiCF ₃ CF ₂ CF ₂ SO ₃ , LiN
_{(CF 3 SO 2) 2,} LiN (C 2 F 5 SO 2) 2 and the like may be used alone or as a mixture of two or more. Among them, LiPF ₆ is preferably used as the electrolyte salt.

As the solid electrolyte, a known solid electrolyte can be used, for example, an inorganic solid electrolyte or a polymer solid electrolyte can be used.

[0032]

EXAMPLES Examples of the present invention will be shown below, but the present invention is not limited thereto. Examples 1 to 7 and Comparative Example 1
4 to 4, the prismatic non-aqueous electrolyte secondary battery 1 shown in FIG. 1 was produced. First, as a positive electrode active material, 1.0 mol of lithium carbonate, 1.0 mol of nickel hydroxide, and 1.0 mol of cobalt hydroxide were mixed, and this mixture was heated in air at a temperature of 7
It was baked at 50 ° C. for 15 hours. When the product was subjected to X-ray diffraction measurement, a single-phase compound was obtained. Therefore, the product is presumed to be LiNi _0.5 Co _0.5 O ₂ .

This Li 91 parts by weight of Ni _0.5 Co _0.5 O ₂ , 3 parts by weight of acetylene black as a conductive material, and 5 parts by weight of polyvinylidene fluoride as a binder are mixed, and N-methyl-2-pyrrolidone is appropriately added and dispersed. , A slurry was prepared. The slurry (T
1) is uniformly applied to both surfaces of the positive electrode current collector 13 made of aluminum having a thickness of 15 to 30 μm, dried, and then compression-molded by a roll press to obtain (T2 + T3) / T1 (T2, T
For No. 3, the positive electrodes 3 having different values of the positive electrode active material layers 15 and 16 were prepared (see Table 1). In addition, in Examples 1 to 7 and Comparative Examples 1 to 4, only the positive electrode 3 is different, and the other components described later are the same.

The negative electrode mixture was prepared by mixing 90 parts by weight of scaly graphite and 10 parts by weight of polyvinylidene fluoride and adding N-methyl-2-pyrrolidone as appropriate to disperse the slurry. The slurry was uniformly applied to a copper negative electrode current collector having a thickness of 10 μm, dried, and compression-molded with a roll press to prepare a negative electrode 4.

As the separator 5, a 25 μm thick microporous polyethylene film was used.

A prismatic non-aqueous electrolyte secondary battery 1 having a width of 48 mm, a height of 90 mm and a thickness of 4.15 mm was produced using the above-mentioned components.

As the non-aqueous electrolyte, ethylene carbonate (EC) and diethyl carbonate (DEC) were mixed at a volume ratio of 30:70, and LiPF ₆ was added to this solution in an amount of 1.2.
Mol / liter dissolved therein was used.

Next, Examples 8 to 12, as a comparative example 5-6, by varying the specific surface area of the cathode active material LiNi _0.5 Co _{0. 5} O _2, prismatic nonaqueous electrolyte secondary specific surface area of the electrode is different Batteries were prepared in the same manner as in Examples 1 to 7 above (see Tables 3 and 4). (T2 + T3) / T1 = 4,
The components other than the specific surface area of the electrode were the same as those in Examples 1 to 7 and Comparative Examples 1 to 4 above. The specific surface area of the electrode here is defined by the value measured by the gas adsorption BET method.

(Normal temperature low load battery capacity test) The rectangular non-aqueous electrolyte secondary batteries 1 of Examples 1 to 12 and Comparative Examples 1 to 6 described above were placed in an environment of 23 ° C. and a maximum voltage of 4 at a constant current of 0.5 A. .2V
After carrying out constant current constant voltage charging (initial charging) for 6 hours,
A room temperature low load battery capacity test was conducted in which constant current discharge was performed at a current of 0.5 A in a 23 ° C. environment to a final voltage of 2.75 V.
The capacity of this room temperature low load battery capacity test is represented by C1.

(Normal temperature heavy load battery capacity test) Two prismatic non-aqueous electrolyte secondary batteries 1 of Examples 1 to 7 and Comparative Examples 1 to 4 described above were used.
In a 3 ° C. environment, a constant current constant voltage of 0.5 A and a constant current constant voltage charge (initial charge) with a maximum voltage of 4.2 V were performed for 6 hours, and then 2
A room temperature heavy load battery capacity test was performed in which constant current discharge was performed at a current of 3 A in a 3 ° C. environment to a final voltage of 2.75 V. Here, when the discharge capacity in the room temperature heavy load battery capacity test is C2 and the capacity in the room temperature low load battery capacity test is C1, the heavy load characteristic is represented by C2 / C1.

(Low-temperature low-load battery capacity test) The rectangular nonaqueous electrolyte secondary batteries 1 of Examples 1 to 12 and Comparative Examples 1 to 6 described above were subjected to a maximum voltage of 4 at a constant current of 0.5 A under an environment of 23 ° C. .2V
After carrying out constant current constant voltage charging (initial charging) for 6 hours,
After left in an environment of 0 ° C. for 1 hour, a low temperature low load battery capacity test was conducted in which constant current discharge was performed at a current of 0.5 A to a final voltage of 2.75 V. Here, when the discharge capacity of the low temperature low load battery capacity test is C3 and the capacity of the above room temperature low load battery capacity test is C1, the low temperature load characteristic is represented by C3 / C1.

(Test Results) The test results of the room temperature low load battery capacity test, the room temperature heavy load battery capacity test, and the low temperature low load battery capacity test are shown in Tables 1 to 5 and FIGS. 3 to 7.

[0043]

[Table 1]

First, the influence of the value of (T2 + T3) / T1 on the capacity C1 in the room temperature low load battery capacity test will be examined. In Table 1 and FIG. 3, 2.5 ≦ (T2 + T
3) / T1 in Examples 1 to 7, 2.5> (T2 + T
It was found that the discharge capacity C1 was large because the energy density was increased as compared with Comparative Examples 1 and 2 of 3) / T1. Further, since C1 of Example 5 is larger than C1 of Examples 6 and 7, it was found that 4.0 ≦ (T2 + T3) / T1 is preferable. Furthermore, C1 of Example 3
However, since it is larger than C1 of Example 5, especially 5.0
It has been found that it is preferable that ≦ (T2 + T3) / T1.

[0045]

[Table 2]

[0046]

[Table 3]

Next, the influence of the value of (T2 + T3) on the heavy load characteristic C2 / C1 and the low temperature load characteristic C3 / C1 will be examined. In Table 2 and FIG. 4, (T2 + T
3) C2 / C1 of Examples 1 to 7 in which ≦ 250 μm is:
(T2 + T3)> 250 μm C2 of Comparative Examples 3 to 4
It was found to be larger than / C1. Example 2
C2 / C1 in Example 2 was larger than C2 / C1 in Example 1, it was found that (T2 + T3) ≦ 200 μm was preferable. Furthermore, C2 / C of Examples 3 and 4
Since 1 is larger than C2 / C1 in Example 2, it was found that (T2 + T3) ≦ 150 μm is particularly preferable.

Further, low temperature load characteristics C shown in Table 3 and FIG.
For 3 / C1, (T2 + T3) ≦ 250 μm, C3 / C1 of Examples 1 to 7 is (T2 + T3)> 25.
It was found to be larger than C3 / C1 of Comparative Examples 3 to 4 which is 0 μm.

The above results were obtained because, when the active material layers 15 and 16 were thicker than 250 μm, lithium ions were transferred from the positive electrode active material layers 15 and 16 on the surface of the positive electrode 3 to the positive electrode active material layer inside the positive electrode 3. It takes a very long time to reach the positive electrode active material layers 15 and 16 in the vicinity of the positive electrode current collectors 15 and 16, that is, the positive electrode current collector 13. As a result, it is considered that the positive electrode active material layers 15 and 16 in the vicinity of the positive electrode current collector 13 could not be effectively used and the heavy load characteristics and the low temperature load characteristics were deteriorated.

From the above results, the thickness T1 of the positive electrode current collector is
And the total thickness (T2 + T3) of the positive electrode active material layer,
2.5 ≦ (T2 + T3) / T1, and (T2 + T3) ≦
By satisfying the relationship of 250 μm, a non-aqueous electrolyte secondary battery having high energy density, excellent heavy load characteristics, and excellent low temperature characteristics can be obtained.

[0051]

[Table 4]

Next, the positive electrode active material Li Ni _0.5 Co _0.5
The influence of the specific surface area of the electrode on the capacity C1 in the room temperature low load battery capacity test is examined by changing the specific surface area of O ₂ . In Table 4 and FIG. 6, it can be seen that the discharge capacity tends to decrease as the specific surface area of the electrode increases, and particularly in Comparative Example 5 in which the electrode has a large specific surface area of 3 m ² / g, the discharge capacity decreases significantly. It was

[0053]

[Table 5]

[0054]

[Table 6]

The influence of the specific surface area of the electrode on the room temperature heavy load characteristic C2 / C1 and the low temperature load characteristic C3 / C1 will be examined. In Table 5 and FIG. 7, it was found that the comparative example 6 in which the specific surface area of the electrode is low has poor normal temperature heavy load characteristics.

The low temperature load characteristic C shown in Table 6 and FIG.
For 3 / C1, the surface area of the specific electrode is 0.01 m ² /
It was found that Comparative Example 6 having a small g was as low as 43%.

From the above results, it is speculated that when the specific surface area of the electrode is increased, the electrode becomes bulky, so that the amount of active material that can be filled in the battery is decreased and the discharge capacity is decreased. on the other hand,
When the specific surface area of the electrode is small, the activity of the electrode decreases, the lithium diffusion rate in the electrode slows down, and the active material in the portion close to the current collector cannot be used, resulting in poor heavy load characteristics and low temperature characteristics. It is presumed that

From the above results, it is preferable to set the specific surface area of the electrode to 0.03 to 2.2 m ² / g in order to achieve a high level of both energy density and low temperature characteristics.

In this embodiment, LiNiCo _0.5 O ₂ was used as the positive electrode active material, but LiNi _0.5 C
o _0.5 O ₂ is a general formula Li _X Ni _1-YZ Co _Y M _Z O
₂ (0.95 ≤ x ≤ 1.25, 0.01 ≤ y ≤ 0.5
0, 0.01 ≦ z ≦ 0.40, M is Ti, Cr, F
It is clear that the same effect can be obtained by using an active material represented by at least one kind of metal selected from e, Mn, Zn, Al, Mo and W).

<Other Embodiments> The present invention is not limited to the embodiments described above and illustrated in the drawings. For example, the following embodiments are also included in the technical scope of the present invention. In addition to the above, various modifications can be made without departing from the scope of the invention.

In the above embodiment, the prismatic non-aqueous electrolyte secondary battery 1 has been described, but the battery structure is not particularly limited, and a cylindrical, lithium polymer battery, and strip-shaped electrodes are laminated with a separator interposed therebetween. Of course, a prismatic battery or the like may be used.

[0062]

According to the positive electrode for a non-aqueous electrolyte secondary battery and the non-aqueous electrolyte secondary battery using the same according to the present invention, the cost is low, the high energy density, the excellent heavy load characteristic, and the excellent low temperature characteristic are provided. Can be obtained.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a prismatic nonaqueous electrolyte secondary battery according to an embodiment of the present invention.

FIG. 2 is a vertical sectional view of a positive electrode according to an embodiment of the present invention.

FIG. 3 is a characteristic diagram showing the relationship between the ratio (T2 + T3) / T1 of the thickness T1 of the positive electrode current collector of the present invention and the thickness (T2 + T3) of the active material layer, and the room temperature low load discharge capacity C1.

FIG. 4 is a characteristic diagram showing the relationship between the thickness (T2 + T3) of the positive electrode active material layer of the present invention and the ratio C2 / C1 of the room temperature low load discharge capacity C1 and the room temperature heavy load discharge capacity C2.

FIG. 5 is a characteristic diagram showing the relationship between the thickness (T2 + T3) of the positive electrode active material layer of the present invention and the ratio C3 / C1 of the room temperature low load discharge capacity C1 and the low temperature low load discharge capacity C3.

FIG. 6 is a characteristic diagram showing the relationship between the specific surface area of the positive electrode of the present invention and room temperature low load discharge capacity C1.

FIG. 7 is a characteristic diagram showing the relationship between the specific surface area of the positive electrode of the present invention and the ratio C2 / C1 of the room temperature low load discharge capacity C1 and the low temperature heavy load discharge capacity C2.

FIG. 8 is a characteristic diagram showing the relationship between the specific surface area of the positive electrode of the present invention and the ratio C3 / C1 of the room temperature low load discharge capacity C1 and the low temperature low load discharge capacity C3.

[Explanation of symbols]

3 ... Positive electrode 13 ... Positive electrode current collector 15 ... Positive electrode active material layer 16 ... Positive electrode active material layer

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 5H029 AJ02 AJ03 AK03 AL02 AL06                       AL07 AL12 AM03 AM04 AM05                       AM07 DJ07 HJ02 HJ04                 5H050 AA02 AA06 AA08 BA17 CA07                       CA08 CB02 CB07 CB08 CB12                       DA02 DA04 HA02 HA04

Claims (2)

[Claims] 1. Li _X Ni _{1-YZ on} both sides of the positive electrode current collector.
Co _Y M _Z O ₂ (0.95 ≦ x ≦ 1.25, 0.01 ≦
y ≦ 0.50, 0.01 ≦ z ≦ 0.40, M is Ti,
A positive electrode provided with a positive electrode active material layer containing at least one metal selected from the group consisting of Cr, Fe, Mn, Zn, Al, Mo, and W. The total thickness (T2 + T3) of the positive electrode active material layer is 2.5 ≦ (T2 + T3) /
A positive electrode for a non-aqueous electrolyte secondary battery, which satisfies T1 and (T2 + T3) ≦ 250 μm. 2. Li _X Ni _{1-YZ on} both sides of the positive electrode current collector.
Co _Y M _Z O ₂ (0.95 ≦ x ≦ 1.25, 0.01 ≦
y ≦ 0.50, 0.01 ≦ z ≦ 0.40, M is Ti,
A positive electrode provided with a positive electrode active material layer containing at least one metal selected from Cr, Fe, Mn, Zn, Al, Mo and W), and a negative electrode current collector provided with a negative electrode active material layer. In a non-aqueous electrolyte secondary battery including a negative electrode and a non-aqueous electrolyte, the total thickness (T2 + T3) of the positive electrode current collector and the positive electrode active material layer is 2.5 ≦ (T2 + T3). / T
1. A non-aqueous electrolyte secondary battery which satisfies the relationship of 1 and (T2 + T3) ≦ 250 μm.