JPH11111293A - Organic electrolyte secondary battery - Google Patents

Abstract

(57) [Problem] To provide an organic electrolyte secondary battery having high capacity and excellent cycle characteristics. A positive electrode, an organic electrolyte secondary battery having a negative electrode and a lithium ion conductive organic electrolyte, as an anode active material, the following composition formula _{(I) Li x M y Ti} 1-y O 2-y (I) (wherein, M is at least one metal selected from the group consisting of Si, Ge, Sn and Pb, and x and y
Is a complex oxide represented by 0 ≦ x ≦ 6, 0.5 ≦ y ≦ 1) or a lithium-containing composite oxide, and a diffraction line of rutile TiO _{2 by} X-ray diffraction measurement Use the one that shows The negative electrode active material is, for example, S
Oxide such as i, Ge, Sn, Pb and rutile type TiO
It is obtained by firing a mixture with a titanium oxide such as ₂ .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an organic electrolyte secondary battery, and more particularly, to an organic electrolyte secondary battery having a high capacity and excellent cycle characteristics.

[0002]

2. Description of the Related Art An organic electrolyte secondary battery represented by a lithium secondary battery has a high capacity, a high voltage and a high energy density.

In this organic electrolyte secondary battery, lithium or a lithium alloy has been used as a negative electrode active material. In the case of using such a negative electrode active material, a high capacity can be expected, but lithium dendrite growth during charging is required. As a result, an internal short-circuit is likely to occur, and therefore, there has been a problem that the battery performance is reduced or the safety is lacking.

Therefore, it has been proposed to use a carbon material such as activated carbon or graphite capable of doping and undoping lithium ions as a negative electrode active material instead of lithium or a lithium alloy (Japanese Patent Publication No. 4-24831). Gazette, Japanese Patent Publication No. Hei 5-17669).

[0005] The above graphite can capture one lithium ion per six carbon atoms, which corresponds to 830 mAh / ml in terms of capacity per unit volume.
However, when graphite is fully charged (containing lithium equivalent to 372 mAh / g), the interlayer distance of this graphite is increased by about 10% as compared with the time of complete discharging (without lithium) due to the entry and exit of lithium ions due to charging and discharging. When charge and discharge are repeated, the expansion / contraction causes graphite as the negative electrode active material to peel off from the current collector or to be pulverized, thereby lowering battery performance. Therefore, to obtain a life of 500 cycles or more with graphite, usually 250 mAh / g (600 mAh / m
l) There is a restriction that the device must be used within the following range.

As a material having a higher capacity than graphite, there is low-crystalline carbon. Since this low-crystalline carbon can insert lithium ions into the voids of the amorphous portion in addition to between the layers, and since there is almost no expansion and contraction of the lattice spacing during charge and discharge,
The cycle life is also expected to be longer. However, this low-crystalline carbon theoretically has a maximum of 1200 mAh / g.
Although a high capacity up to (ie, a state of C2Li) can be expected, the true density is low and the capacity per volume is not much different from graphite.

[0007] Therefore, a high capacity is achieved by using an oxide mainly composed of a semi-metal belonging to Group IVB or VB in the periodic table as a negative electrode active material (Japanese Patent Laid-Open No. 6-2752).
No. 68, Japanese Unexamined Patent Publication No. 7-122274), and an attempt to increase the capacity by using silicon oxide as a negative electrode active material has been proposed (Japanese Unexamined Patent Publication No. 6-32).
5765, JP-A-7-29602, JP-A-9-7638).

However, the oxide-based negative electrode active material as described above is suitable for increasing the capacity because it can contain a large amount of lithium ions, but has a problem of poor cycle characteristics.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems in the prior art and to provide an organic electrolyte secondary battery having a high capacity and excellent cycle characteristics. .

[0010]

Means for Solving the Problems The present invention, as the negative electrode active material in the composition formula _{(I) Li x M y Ti} 1-y O 2-y (I) ( wherein, M is Si, Ge, Sn and At least one metal selected from the group consisting of Pb, x and y
Is a complex oxide represented by 0 ≦ x ≦ 6, 0.5 ≦ y ≦ 1) or a lithium-containing composite oxide, and a diffraction line of rutile TiO _{2 by} X-ray diffraction measurement The above-mentioned problem was solved by using the one with the above.

In the present invention, the reason why the cycle characteristics can be improved while maintaining a high capacity by using the above-mentioned negative electrode active material is not necessarily clear at present, but is considered as follows. In other words, oxides contain lithium ions only when MO (M is Si, Ge, Sn).
And at least one metal selected from the group consisting of Pb and Pb), it is considered that MO alone is preferable for simply producing a high-capacity negative electrode active material, but this MO is used in an organic electrolyte secondary battery. In this case, a large amount of lithium ions are doped / dedoped by charge / discharge, so that expansion and contraction are repeated violently, so that the MO itself becomes finer and easily peels off from the current collector. Therefore, improving the coexistence of TiO ₂ to MO, since TiO ₂ is suppressed確壊of the negative electrode associated with functional charge and discharge were as cushioning material wrapped MO, thereby keeping the high capacity, the cycle characteristics It is thought that it can be done. In particular, rutile TiO ₂ easily allows lithium ions to pass therethrough, is physically and chemically stable even when coexisting with MO, and does not hinder the action of MO.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The composite oxide represented by the composition formula (I) used as a negative electrode active material in the present invention is generally S
It is obtained by firing a mixture containing an oxide of at least one metal selected from the group consisting of i, Ge, Sn and Pb and a rutile-type titanium oxide. More specifically, it is obtained by calcining a mixture of MO and rutile-type TiO _2, and is obtained by synthesizing a composite oxide represented by the composition formula (I) using raw materials and methods other than those described above. Is also good.

The composite oxide represented by the composition formula (I) used as the negative electrode active material in the present invention does not necessarily need to contain lithium at the time of being incorporated as a battery. Part of the lithium inserted into the negative electrode during charging and discharging remains permanently.
Since it is inefficient to compensate for this with an excess of the positive electrode, it is preferable to previously contain lithium equivalent to the irreversible capacity chemically or electrochemically. Alternatively, metallic lithium equivalent to the irreversible capacity may be attached to the negative electrode, or a material having a large irreversible capacity may be used for the positive electrode active material.

In particular, when the composite oxide represented by the composition formula (I) has a molar ratio of lithium to oxygen of 2 or less before assembling into a battery, excess oxygen takes in lithium to convert Li ₂ O to Since this Li ₂ O has an irreversible capacity that does not contribute to subsequent charging and discharging, in order to supply lithium equivalent to the irreversible capacity, metal lithium is attached to the negative electrode, or the positive electrode active material is It is preferable to use a substance having an irreversible capacity of 20% or more. Examples of the positive electrode active material having a large irreversible capacity as described above include LiNiO ₂ and LiNiO _2.
2 to which a transition metal such as Co is added, Li ₂ Mn ₂
O _{4 and the} like.

In the organic electrolyte secondary battery of the present invention, the discharge end voltage can be up to 1.5 V with respect to the potential of the lithium metal, but if it is 1.0 V or less, the cycle life can be extended. 1.0V against metal lithium potential
The following corresponds to a battery voltage of 3.2 V or more when LiCoO ₂ is used for the positive electrode.

In the present invention, when preparing the negative electrode, for example, a conductive oxide is added to the negative electrode active material comprising the composite oxide represented by the above-mentioned composition formula (I) or lithium-containing composite oxide, if necessary. A negative electrode mixture is prepared by adding an agent or a binder, and the mixture is pressure-formed to produce a negative electrode, or a solvent is added to the negative electrode mixture to prepare a slurry-like paint, and the paint is prepared. A method in which a negative electrode is produced through a process of applying the composition to a current collector also serving as a support and drying it to form a coating film made of a negative electrode mixture is employed. However, the method for manufacturing the negative electrode is not limited to the above examples, and another method may be adopted.

Examples of the conductive aid include non-carbon-based materials such as nickel powder and carbon-based materials such as graphite, acetylene black, carbon black, and coke. A low-crystalline carbon material having an interlayer distance (d ₀₀₂ ) of the (002) plane of 0.338 nm or more is preferable. The amount of the conductive additive is not particularly limited, but is 1 to 30% by weight based on the negative electrode active material.
Is preferable, and 2 to 15% by weight is more preferable. As the binder, for example, polyvinylidene fluoride,
Examples include polytetrafluoroethylene, polyacrylic acid, and ethylene propylene diene rubber. The amount of the binder added is not particularly limited, but is preferably 1 to 50% by weight, more preferably 2 to 20% by weight, based on the negative electrode active material.

In the present invention, the positive electrode active material is not particularly limited, and various types can be used. For example, lithium composite oxides such as LiNiO ₂ , CiCoO ₂ , and LiMn ₂ O ₄ have high voltage. It is preferably used because it is obtained. Then, in producing the positive electrode, for example, if necessary, a conductive additive,
Prepare a positive electrode mixture by adding a binder and the like, or adopt a method of producing a positive electrode by press-molding it, or prepare a slurry paint by adding a solvent to the positive electrode mixture,
A method in which the paint is applied to a current collector also serving as a support and dried to form a positive electrode mixture coating film to form a positive electrode is adopted. However, the method for manufacturing the positive electrode is not limited to the above-described example, and another method may be adopted. In addition, as a conductive assistant and a binder,
The same thing as the case of the said negative electrode can be used, and the usage amount with respect to the positive electrode active material may be about the same as the usage amount with respect to the said negative electrode active material.

The organic electrolyte is not particularly limited. For example, 1,2-dimethoxyethane, 1,2-diethoxyethane, propylene carbonate, ethylene carbonate, γ-butyrolactone, tetrahydrofuran, In a single solvent such as 1,3-dioxolane, diethyl carbonate, dimethyl carbonate, ethyl methyl carbonate or a mixed solvent of two or more, for example, LiClO ₄ , LiPF ₆ , LiBF ₄ , LiAs
F ₆ , LiSbF ₆ , LiCF ₃ SO ₃ , LiC ₄ F ₉
SO ₃ , LiCF ₃ CO ₂ , Li ₂ C ₂ F ₄ (SO ₃ )
₂ , LiN (CF ₃ SO ₂ ) ₂ , LiC (CF ₃ S
An electrolyte such as O ₂ ) ₃ and LiC _n F _{2n + 1} SO ₃ (n ≧ 2) is used alone or prepared by dissolving two or more of them.

[0020]

Next, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to only these examples.

Example 1 PbO and rutile TiO ₂ were mixed at a molar ratio of 1: 1 as a negative electrode active material, and mixed in an electric furnace in an argon atmosphere.
A composite oxide obtained by calcining at 000 ° C. for 10 hours was pulverized with a ball mill. This composite oxide is represented by a composition formula of Pb _0.5 Ti _0.5 O _1.5 . This will be described based on the composition formula (I). In the composition formula (I), x = 0, M = Pb, and y = 0.5.

To 100 parts by weight of the above Pb _0.5 Ti _0.5 O _1.5 , 15 parts by weight of flaky graphite as a conductive aid, and polyvinylidene fluoride as a binder were polyfluorinated with a 12.5 vol% N-methylpyrrolidone solution. 5 parts by weight of vinylidene was added as a solid content, mixed, and further diluted with N-methylpyrrolidone to an appropriate viscosity. This was stirred in a fume hood at room temperature for 2 hours, and further heated to 150 ° C. in a vacuum with stirring to completely volatilize N-methylpyrrolidone. The dried and solidified product was pulverized in a mortar and dried again in vacuum at 100 ° C. for 5 hours to obtain a negative electrode mixture. This negative electrode mixture was 10 mm in diameter and 0.1 mm in thickness.
It was press-formed into a 3 mm pellet shape, and a nickel net, which also served as a current collector, was pressed against both surfaces and reinforced. The pellets of the negative electrode as a working electrode, using a lithium foil as a counter electrode and a reference electrode, a volume ratio of the LiPF ₆ and ethylene carbonate and ethyl methyl carbonate 1: 1 in a mixed solvent of 1 mole /
A cell was prepared using a solution dissolved at a concentration of 1 liter as an organic electrolyte.

Example 2 A cell was fabricated in the same manner as in Example 1 except that SnO was used instead of PbO of Example 1. The negative electrode active material of Example 2 is Sn _0.5 Ti _0.5 O _{1.5 when} represented by the composition formula. This will be described based on the composition formula (I).
0, M = Sn, y = 0.5.

Example 3 A cell was fabricated in the same manner as in Example 1 except that GeO was used instead of PbO of Example 1. The negative electrode active material of Example 3 is Ge _0.5 Ti _0.5 O _1.5 in composition formula. This will be described based on the composition formula (I).
0, M = Ge, y = 0.5.

With respect to the negative electrode active materials of Examples 1 to 3,
When an X-ray diffraction measurement was performed, it was confirmed that rutile TiO ₂ coexisted in any of the negative electrode active materials. X above
X-ray diffraction measurement was performed using RAD-RC manufactured by Rigaku Corporation with an X-ray source of CuKα radiation at room temperature, 40 kv, 150 mA, scanning speed of 2 ° / min, SLIT DS 1 RS. 6SS1
I went in.

Comparative Example 1 A cell was prepared in the same manner as in Example 1 except that PbO was used as the negative electrode active material.

Comparative Example 2 A cell was manufactured in the same manner as in Example 1 except that SnO was used as the negative electrode active material.

Comparative Example 3 A cell was produced in the same manner as in Example 1 except that GeO was used as the negative electrode active material.

Comparative Example 4 A cell was fabricated in the same manner as in Example 1 except that the molar ratio of SnO to rutile TiO ₂ was changed to 4: 1. The composition of the negative electrode active material of Comparative Example 4 was Sn _0.8 Ti _0.2 O _1.2 , and the amount of Ti was smaller than that of the composition formula (I).

X-ray diffraction measurement was performed on the negative electrode active material of Comparative Example 4 in the same manner as in Example 1.
iO ₂ was not observed.

The prepared cell was charged and discharged at a constant current of 0.2 mA / cm ^{2 with} a potential of 1.5 V to 50 mV with respect to lithium. However, in Example 2 and Comparative Example 2, charge / discharge was performed at a potential with respect to lithium of 1.0 V to 50 mV.

Table 1 shows the charge capacity and the discharge capacity per unit volume of the negative electrode mixture (including the conductive auxiliary agent and the binder), the irreversible capacity ratio (the ratio of the irreversible capacity to the initial charge capacity) of the cells of Examples and Comparative Examples, The retention ratio of the discharge capacity at the 100th cycle with respect to the initial discharge capacity is shown.

[0033]

[Table 1]

As is clear from the results shown in Table 1, Examples 1 to 3 have a higher retention ratio of the discharge capacity at the 100th cycle with respect to the initial discharge capacity and are superior in cycle characteristics as compared with Comparative Examples 1 to 4. I was

Further, Examples 1 to 3, there discharge capacity per unit volume of the negative electrode mixture is in the range of 0.8~1.1Ah / cc, a comparison of MO alone the introduction of TiO ₂ Examples 1-3
Although the initial discharge capacity was lower than that of the graphite negative electrode, it was still higher than the graphite anode of about 0.4 Ah / cc, and was sufficiently high for practical use.

[0036] After the Example 4 LiPF ₆ was dissolved in trimethyl phosphate, by mixing the addition of ethylene carbonate, the volume ratio of the trimethyl phosphate and ethylene carbonate 98: a LiPF ₆ in a mixed solvent of 2 1. An organic electrolyte in which 0 mol / liter was dissolved was prepared.

In addition, lithium cobalt oxide (LiCo
6 parts by weight of graphite and 3 parts by weight of polyvinylidene fluoride were added to 91 parts by weight of O ₂ ) to prepare a positive electrode mixture, which was dispersed with N-methylpyrrolidone to prepare a slurry-like paint.
The slurry-like paint containing the positive electrode mixture is coated with a thickness of 20 μm.
m, uniformly coated on both sides of a positive electrode current collector made of aluminum foil, and dried to form a coating film made of a positive electrode mixture,
Compression molding was performed by a roller press machine, and the lead body was welded to produce two sheet-shaped positive electrodes having a thickness of 160 μm.

Apart from the above, Pb synthesized in Example 1
_0.5 Ti _0.5 O _1.5 45 parts by weight of graphite and 40 parts by weight of graphite and 15 parts by weight of polyacrylic acid were mixed to prepare a negative electrode mixture,
This was dispersed in water to prepare a slurry paint. The slurry-like paint containing the negative electrode mixture was coated to a thickness of 18 μm.
After uniformly coating both surfaces of the negative electrode current collector made of copper foil and drying to form a coating film made of the negative electrode mixture, compression molding with a roller press, welding of the lead body, and thickness of 40 μm
m of the sheet-shaped negative electrode was produced.

Next, one of the sheet-like positive electrodes and the sheet-like negative electrode were overlapped with a separator made of a microporous polypropylene film having a thickness of 25 μm interposed therebetween, and spirally wound. After preparing a spiral electrode body, filling the spiral electrode body into a bottomed cylindrical battery case having an outer diameter of 18 mm, welding the positive and negative electrode leads, and then charging the organic electrolytic solution with the battery. It was poured into the case, and then the opening of the battery case was sealed to produce a cylindrical organic electrolyte secondary battery. The detailed configuration of this battery will be described later with reference to FIG.

When this battery was charged to 4.1 V at 20 ° C. and 0.2 C, and then discharged to 2.75 V at 0.2 C, the charge capacity was 1.6 Ah and the discharge capacity was 0.4 A.
h. The reason why the discharge capacity is smaller than the charge capacity is that the negative electrode has an irreversible capacity.

Therefore, the battery was disassembled in an argon gas atmosphere, only the negative electrode was taken out, the surface was washed with methyl ethyl carbonate, and the other sheet-like positive electrode was used again through a separator to separate the sheet-like electrode. And wound spirally to produce a spiral electrode body, and using the spiral electrode body in the same procedure as described above to obtain an outer diameter of 18 mm.
Was manufactured.

The battery was charged at 2.75 V at 20 ° C. and 0.2 C.
When charging and discharging were performed in a range of up to 4.1 V, the first charging capacity was 1.5 Ah, and the subsequent charging and discharging was 1.4 Ah.
Was almost constant. This battery exhibited a discharge capacity of 80% or more of the first discharge capacity even after 100 cycles.

Here, the battery shown in FIG. 1 will be described. 1 is the above-mentioned sheet-like positive electrode, and 2 is the sheet-like negative electrode. However, FIG. 1 does not show a metal foil or the like as a current collector used in manufacturing the positive electrode 1 or the negative electrode 2 in order to avoid complication. The positive electrode 1 and the negative electrode 2 are spirally wound with a separator 3 interposed therebetween, and serve as a spiral electrode body together with the organic electrolytic solution 4 and a battery case 5.
Housed within.

The battery case 5 is made of stainless steel and also serves as a negative electrode terminal. Before the insertion of the spiral electrode body, an insulator 6 made of polytetrafluoroethylene is arranged at the bottom of the battery case 5. ing. The sealing plate 7 is made of aluminum, has a disk shape, and has a thin portion 7a at the center.
Are provided on the inner side from both end surfaces in the thickness direction, and a hole is provided around the thin portion 7 a as a pressure introduction port 7 b for allowing the internal pressure of the battery to act on the explosion-proof valve 9. The projection 9a of the explosion-proof valve 9 is welded to the upper surface of the thin portion 7a to form a welded portion 11. The thin portion 7a provided on the sealing plate 7 and the protruding portion 9a of the explosion-proof valve 9 are
For easy understanding in the drawings, only the cut surface is shown, and the outline behind the cut surface is omitted. Also, the welded portion 11 between the thin portion 7a of the sealing plate 7 and the protruding portion 9a of the explosion-proof valve 9 is shown in an exaggerated state in order to facilitate understanding on the drawing.

The terminal plate 8 is made of rolled steel, has a nickel-plated surface, and has a hat-like shape with a brim-shaped peripheral portion. The terminal plate 8 is provided with a gas discharge hole 8a. . The explosion-proof valve 9 is made of aluminum and is in the shape of a disk, and a central portion is provided with a projecting portion 9a having a tip on the power generation element side (the lower side in FIG. 1). As described above, the lower surface is welded to the upper surface of the thin portion 7a of the sealing plate 7 to form a welded portion 11. The insulating packing 10 is made of polypropylene and has an annular shape. The insulating packing 10 is disposed above the peripheral edge of the sealing plate 7 and has an explosion-proof valve 9
Are arranged to insulate the sealing plate 7 and the explosion-proof valve 9 and seal the gap between the two so that the organic electrolyte does not leak from between them. The annular gasket 12 is made of polypropylene, and the lead body 13 is made of aluminum. The sealing plate 7 and the positive electrode 1 are connected to each other. An insulator 14 is disposed above the spiral electrode body. The bottom portion is connected by a lead body 15 made of nickel.

As described above, the insulator 6 is disposed at the bottom of the battery case 5, and the spiral electrode body including the positive electrode 1, the negative electrode 2 and the separator 3, the organic electrolyte solution 4, and the upper part of the spiral electrode body are provided. The insulator 14 and the like are housed in the battery case 5, and after the housing, an annular groove having a bottom protruding inward is formed in the vicinity of the open end of the battery case 5. An annular gasket 12 having a sealing plate 7, an insulating packing 10, and an explosion-proof valve 9 inserted into the opening of the battery case 5 is provided.
, And the terminal plate 8 is inserted from above, and the portion of the battery case 5 beyond the groove is fastened inward, whereby the opening of the battery case 5 is sealed. However,
When assembling the battery as described above, the anode 2
It is preferable that the battery case 5 is connected to the positive electrode 1 and the sealing plate 7 by the lead 13.

In the battery assembled as described above, the thin portion 7a of the sealing plate 7 and the projection 9a of the explosion-proof valve 9 are provided.
Contact at the welded portion 11, the peripheral portion of the explosion-proof valve 9 and the peripheral portion of the terminal plate 8 come into contact, and the positive electrode 1 and the sealing plate 7 are connected by the lead 13 on the positive electrode side. And terminal plate 8
The electrical connection is obtained by the lead body 13, the sealing plate 7, the explosion-proof valve 9 and the welded portion 11 thereof, and the lead body normally functions as an electric circuit.

When an abnormal situation occurs in the battery and gas is generated inside the battery and the internal pressure of the battery rises, the internal pressure rises and the central part of the explosion-proof valve 9 moves in the direction of the internal pressure (FIG. 1).
Then, it is deformed in the upper direction)
The shearing force acts on the thin portion 7a integrated at 1 and the thin portion 7a is broken or the projection 9a of the explosion-proof valve 9 is formed.
And the thin portion 7a of the sealing plate 7 is peeled off, whereby the electrical connection between the positive electrode 1 and the terminal plate 8 is lost and the current is cut off. As a result, the battery reaction does not proceed, so that even during overcharging or short-circuiting, the battery temperature rise and internal pressure rise due to the charging current and short-circuit current do not progress further, so that ignition and rupture of the battery are prevented. become.

The explosion-proof valve 9 is provided with a thin portion 9b. For example, when charging proceeds extremely and power generation elements such as an organic electrolyte and an active material are decomposed and a large amount of gas is generated. Means that the explosion-proof valve 9 is deformed,
After the welded portion 11 of the sealing plate 7 and the thin portion 7a of the sealing plate 7 are peeled off, the thin portion 9b provided on the explosion-proof valve 9 is ruptured to discharge gas from the gas discharge hole 8a of the terminal plate 8 to the outside of the battery. The battery can be prevented from bursting.

As shown in Embodiment 4, even in the above mounted battery, the battery of the present invention is the same as that of Embodiments 1 to 4.
As in the case of the model cell No. 3, the battery has high capacity and excellent cycle characteristics.

By the way, a battery was produced in the same manner as in Example 4 except that PbO was used as a negative electrode active material in the same manner as in Comparative Example 1 instead of Pb _0.5 Ti _0.5 O _1.5 , and the same conditions as in Example 4 were used. When charging and discharging were performed, no discharge capacity was obtained after 100 cycles.

[0052]

As described above, according to the present invention, an organic electrolyte secondary battery having a high capacity and excellent cycle characteristics can be provided.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an example of an organic electrolyte secondary battery according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Positive electrode 2 Negative electrode 3 Separator 4 Organic electrolyte

Claims (6)

[Claims] 1. A positive electrode in the organic electrolytic solution secondary battery having a negative electrode and a lithium ion conductive organic electrolyte, the negative electrode active material, the following composition formula _{(I) Li x M y Ti} 1-y O 2- _y (I) (where M is at least one metal selected from the group consisting of Si, Ge, Sn and Pb, x and y
Is a complex oxide represented by 0 ≦ x ≦ 6, 0.5 ≦ y ≦ 1) or a lithium-containing composite oxide, and a diffraction line of rutile TiO _{2 by} X-ray diffraction measurement An organic electrolyte secondary battery characterized by the fact that it is observed. 2. The method according to claim 1, wherein the negative electrode active material comprises at least Si, Ge,
2. The organic oxide according to claim 1, wherein the composite oxide is obtained by firing a mixture containing an oxide of at least one metal selected from the group consisting of Sn and Pb and a rutile-type titanium oxide. Electrolyte secondary battery. 3. An organic electrolyte secondary battery, wherein the negative electrode active material is obtained by electrochemically inserting lithium into the composite oxide obtained in claim 2. 4. The organic electrolytic solution according to claim 1, wherein when the molar ratio of lithium to oxygen of the negative electrode active material before the battery is incorporated is 2 or less, metal lithium to supplement the molar ratio is attached to the negative electrode. Next battery. 5. The method according to claim 1, wherein a material having an irreversible capacity of 20% or more is used as the positive electrode active material when the molar ratio of lithium to oxygen of the negative electrode active material before the battery is incorporated is 2 or less. Organic electrolyte secondary battery. 6. The discharge termination voltage according to claim 1, wherein the discharge end voltage is 3.2.
An organic electrolyte secondary battery characterized by being at least V.