JPH06176758A - Nonaqueous electrolyte secondary battery - Google Patents

Abstract

PURPOSE:To provide a new nonaqueous electrolyte secondary battery of excellent electric charging/discharging characteristics and of long cycle life, and an active material of the electrode. CONSTITUTION:In a nonaqueous electrolyte secondary battery which is composed of at least a negative electrode, a positive electrode, and a nonaqueous electrolyte of lithium ion conductivity, a compound oxide of metal and lithium is used, which is expressed by a composition formula of LixMO, where M is at least one element among Mn, Ti, and Zn, and 0<=x, as an active material for either/both of the negative electrode or/and the positive electrode. The electric charging/discharging amount becomes large and of high energy density. Since the polarization (inner resistance) at the time of electric charging/discharging is small, charging/discharging of large current is facilitated, while degradation due to excess charging/discharging is reduced, and the cycle life is extended.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-aqueous electrolyte secondary battery in which a substance capable of inserting and extracting lithium is used as a negative electrode active material and / or a positive electrode active material and a lithium ion conductive non-aqueous electrolyte is used. In particular, the present invention relates to a novel negative electrode active material and a positive electrode active material that provide a new secondary battery having high voltage, high energy density, excellent charge / discharge characteristics, and long cycle life.

[0002]

2. Description of the Related Art Non-aqueous electrolyte batteries using lithium as a negative electrode active material have advantages such as high voltage, high energy density, low self-discharge and excellent long-term reliability. It is already widely used as a power source for cameras. However, with the remarkable development of portable electronic devices and communication devices in recent years,
A wide variety of devices that require a large current output for batteries as power sources have emerged, and rechargeable / dischargeable, high energy-density secondary batteries are strongly demanded from the viewpoint of economy and reduction in size and weight of devices. Has been done. For this reason, research and development for promoting the non-aqueous electrolyte battery having a high energy density into a secondary battery have been actively carried out, and some of them have been put into practical use, but energy density, charge / discharge cycle life, reliability, etc. It is still insufficient.

Conventionally, as the positive electrode active material constituting the positive electrode of this type of secondary battery, depending on the form of charge / discharge reaction, the following 3
Some types of species have been found. The first type is a metal chalcogenide such as TiS ₂ , MoS ₂ , NbSe ₃ or MnO ₂ , MoO ₃ , V ₂ O ₅ , Li _X CoO ₂ or L.
Like metal oxides such as i _x NiO ₂ and Li _x Mn ₂ O _4, only lithium ions (cations) are involved in intercalation and deintercalation reactions between crystal layers or between lattice positions or lattice gaps. Type that goes in and out.

The second type is a type such as a conductive polymer such as polyaniline, polypyrrole, polyparaphenylene, etc. in which mainly anions are stably doped and come in and out by a dedoping reaction. The third type is a type (intercalation, deintercalation or doping, dedoping, etc.) in which both lithium cations and anions can enter and exit, such as graphite intercalation compounds and conductive polymers such as polyacene. .

On the other hand, as the negative electrode active material constituting the negative electrode of this type of battery, when metal lithium is used alone, the electrode potential is the most base, so that it is combined with the positive electrode using the positive electrode active material as described above. The battery has the highest output voltage and high energy density and is preferable, but there is a problem that dendrites and passivation compounds are generated on the negative electrode during charging and discharging, the deterioration due to charging and discharging is large, and the cycle life is short.

In order to solve this problem, (1) lithium and Al, Zn, Sn, Pb, Bi, C as a negative electrode active material
alloys with other metals such as d, (2) WO ₂ , MoO ₂ , Fe ₂
O _3, TiS inorganic compounds such as ₂ or graphite, intercalation compound was occluded lithium ions carbonaceous material like crystal structure obtained by firing an organic substance or insertion compound, and (3) Lithium-ion de - and up It has been proposed to use a substance capable of inserting and extracting lithium ions, such as a conductive polymer such as polyacene or polyacetylene.

[0007]

However, generally, a negative electrode using a material capable of inserting and extracting lithium ions other than metallic lithium as described above as a negative electrode active material, and a positive electrode active material as described above are used. When a battery is constructed by combining the positive electrode and the negative electrode active material, the electrode potential of these negative electrode active materials is nobler than the electrode potential of metallic lithium. It has the drawback of being significantly lower. For example, lithium and A
0.2 to 0.8 V when an alloy such as 1, Zn, Pb, Sn, Bi, or Cd is used, 0 to 1 V for a carbon-lithium intercalation compound, and 0 for a lithium ion insertion compound such as MoO ₂ or WO _2. The operating voltage is reduced by 0.5 to 1.5V.

Further, since elements other than lithium also serve as negative electrode constituents, the capacity and energy density per volume and weight are significantly reduced. Furthermore, when the alloy of (1) above with lithium and another metal is used, the utilization efficiency of lithium during charging and discharging is low, and cracks occur in the electrode due to repeated charging and discharging, and the like. Therefore, there is a problem that the cycle life is short, and in the case of the lithium intercalation compound or the intercalation compound of (2), there is deterioration such as collapse of the crystal structure or generation of an irreversible substance due to overcharge and discharge, and a high electrode potential ( There is a disadvantage that the output potential of the battery using this is low, and in the case of the conductive polymer of (3), the charge / discharge capacity, especially the charge / discharge capacity per volume is small. There's a problem.

Therefore, in order to obtain a secondary battery having high voltage, high energy density, excellent charge / discharge characteristics, and long cycle life, the electrode potential with respect to lithium is low (base), and lithium during charge / discharge is low. There is a need for a negative electrode active material which does not cause deterioration such as crystal structure collapse and generation of irreversible substances due to occlusion / release of ions, and which has a large reversible occlusion / release of lithium ions, that is, a large effective charge / discharge capacity.

On the other hand, in the above-mentioned positive electrode active material, the first type generally has a large energy density, but has a drawback that when it is overcharged or overdischarged, it is greatly deteriorated due to crystal collapse or generation of an irreversible substance. . On the contrary, the second and third types have a drawback that the capacity and energy density are small.

Therefore, in order to obtain a secondary battery having excellent overcharge characteristics and overdischarge characteristics and having a high capacity and a high energy density, there is no crystal collapse or irreversible substance formation due to overcharge / overdischarge, and A positive electrode active material having a larger amount capable of reversibly inserting and extracting lithium ions is required.

[0012]

In order to solve the above problems, the present invention is represented by a composition formula Li _x MO as an active material of at least one of a negative electrode and a positive electrode of this type of battery. , M is at least one metal selected from Mn, Ti and Zn, and a novel lithium ion storage / release material comprising a composite oxide of a metal represented by 0 ≦ x and lithium is used. It is something to raise.

That is, the composition ratio of the metal M and oxygen is about 1:
A composite oxide which is the oxide of No. 1 and which contains lithium in its crystal structure or amorphous structure and is capable of inserting and extracting lithium ions by an electrochemical reaction in a non-aqueous electrolyte is used. As described above, the standard composition ratio of metal M to oxygen O is 1: 1. However, in the synthesis, a nonstoichiometric compound is often formed due to the deficiency of metal M or oxygen O, and the range of the deficiency is M. Depending on the type, it reaches ± 25%. Such nonstoichiometric composition is also included in the present invention. The content x of lithium may be in the range in which the composite oxide is stably present, and the range of 0 ≦ x ≦ 2 is particularly preferable.

The following two types of methods can be mentioned as preferable methods for producing the composite oxide used as the active material of the negative electrode and / or the positive electrode of the battery of the present invention, but the method is not limited thereto. The first method is to mix each of the above metal elements and lithium or their oxygen-containing compounds in a predetermined molar ratio, and heat in an inert atmosphere, a vacuum, or an atmosphere in which the amount of oxygen is controlled. It is a method of synthesizing. The respective compounds of the metal and lithium as the starting materials are the respective oxides, hydroxides, salts of carbonates, nitrates or the like, or organic compounds, etc., which are oxidized by heating in an inert atmosphere or in a vacuum. Any compound that produces a substance may be used. Although the heating temperature varies depending on the starting material and the heating atmosphere, the synthesis is possible at 400 ° C or higher, preferably 600 ° C or higher, more preferably 700 ° C or higher.

The composite oxide of the metal and lithium thus obtained is used as it is or after being subjected to processing such as pulverizing and granulating, if necessary, as an active material for the negative electrode and / or the positive electrode. In addition, as in the second method described below, further lithium ions can be added to this composite oxide by an electrochemical reaction between the lithium-containing composite oxide and metallic lithium or a substance containing lithium. It is also possible to use as the active material a material in which the lithium content is increased or decreased by occluding hydrogen, or conversely by releasing lithium ions from this composite oxide.

The second method is to use Mn, Ti, MnO, TiO, ZnO, a mixture thereof, a complex oxide, or the like.
And / or Zn monoxide MO and electrochemically reacting lithium or a substance containing lithium to cause the monoxide MO to occlude lithium ions to obtain a composite oxide of the metal M and lithium. Is the way.

As the substance containing lithium for use in this electrochemical reaction, for example, a lithium ion which is used for the positive electrode active material or the negative electrode active material mentioned in the above-mentioned section of the prior art can be stored and released. Possible substances can be used. Such storage of lithium ions by the electrochemical reaction of metal monoxide MO can be performed inside the battery after the battery is assembled, or inside or outside the battery during the battery manufacturing process. Specifically, it can be performed as follows.

That is, (1) one electrode (working electrode) is formed by molding a monoxide of the metal or a mixture of the metal oxide and a conductive agent, a binder or the like into a predetermined shape. A substance containing is used as the other electrode (counter electrode) in contact with a lithium ion conductive non-aqueous electrolyte so that both electrodes face each other to form an electrochemical cell, and the working electrode is suitable for cathodic reaction. A method of electrochemically occluding lithium ions in the monoxide by energizing or discharging with an electric current.
The obtained working electrode is used as it is as a negative electrode and / or a positive electrode or as an active material constituting a negative electrode and / or a positive electrode to form a non-aqueous electrolyte secondary battery.

(2) Monooxides of the metal or a mixture of the metal oxides with a conductive agent, a binder and the like are formed into a predetermined shape, and lithium or an alloy of lithium or the like is pressure-bonded or contacted thereto and laminated. The thing is incorporated into a non-aqueous electrolyte secondary battery as an electrode. A method of forming a kind of local battery by contacting the laminated electrode with an electrolyte in the battery and self-discharging to electrochemically occlude lithium in the monoxide.

(3) A non-aqueous electrolyte secondary battery in which the oxide of the metal is used as the active material of one electrode and the other electrode contains lithium and can absorb and release lithium ions as the active material. Make up. A method in which lithium ions are occluded in the monoxide by charging or discharging when used as a battery.

The composite oxide Li _x MO of the metal M and lithium thus obtained is used as an active material for the negative electrode and / or the positive electrode. The complex oxide Li _x M according to the present invention
An electrode using O as an active material can be used as a positive and negative electrode active material to form a secondary battery, or can be used as either a positive electrode or a negative electrode to obtain the lithium or An electrode using various other negative electrode active material or positive electrode active material capable of inserting and extracting lithium ions can be used in combination as the other electrode.

In particular, the complex oxide Li according to the present invention_xMO
The electrode whose active material is
Has a large charge / discharge capacity in a base area of 1.5 V or less, and
Since the deterioration due to overcharge and overdischarge is small, this is used as the negative electrode.
Used for V₂O_FiveAnd Li _xCoO₂, Li_xNiO₂,
Li_xMn₂O_Four Against metallic lithium such as metal oxides
Active material with high electrode potential of 3V or 4V or more
High voltage and high energy by combining with a positive electrode using
Gee density and excellent charge / discharge characteristics for large current, overcharge / overdischarge
A secondary battery with less deterioration due to
Good

On the other hand, as the electrolyte, γ-butyrolactone, propylene carbonate, ethylene carbonate,
Butylene carbonate, dimethyl carbonate, diethyl carbonate, methyl fomate, 1,2-dimethoxyethane, tetrahydrofuran, dioxolane, dimethylformamide, etc., alone or in a mixed solvent of an organic solvent such as LiClO as a supporting electrolyte. ₄ , LiPF ₆ , LiBF
₄ , an organic electrolytic solution in which a lithium ion dissociable salt such as LiCF ₃ SO ₃ is dissolved, a solid polymer electrolyte in which the lithium salt is solid-dissolved in a polymer such as polyethylene oxide or a crosslinked polyphosphazene, or Li ₃ N, Any lithium ion conductive non-aqueous electrolyte such as an inorganic solid electrolyte such as LiI may be used.

[0024]

The electrode of the present invention, which uses the composite oxide Lix MO of the metal M and lithium selected from Mn, Ti, and Zn as the active material, has at least 0 relative to metallic lithium in the non-aqueous electrolyte. A secondary battery capable of stably occluding and releasing lithium (intercalation, deintercalation or doping, dedoping, etc.) repeatedly in an electrode potential range of up to 3 V and capable of being repeatedly charged and discharged by such an electrode reaction. Can be used as the negative electrode and / or the positive electrode. In particular, in a base potential region of 0 to 1.5 V with respect to the lithium reference electrode, it has a high capacity region in which lithium ions can be occluded and released stably and can be repeatedly charged and discharged.

Further, as compared with a carbonaceous material such as graphite which has been conventionally used as an electrode of a battery of this type, the amount capable of reversibly occluding and releasing lithium ions, that is, the charging / discharging capacity is remarkably large and the polarization of charging / discharging is small. Therefore, charging / discharging with a large current is possible, and deterioration such as decomposition or crystal collapse due to overcharging / overdischarging is hardly seen, and an extremely stable battery having a long cycle life can be obtained.

The reason why such excellent charge / discharge characteristics are obtained is not always clear, but it is presumed as follows. That is, the composite oxide Li _x MO of the metal M and lithium, which is the novel active material according to the present invention, has a high mobility of lithium ions in this structure and has a site that can store lithium ions. It is presumed that it is easy to insert and extract lithium ions due to the large amount. Hereinafter, the present invention will be described in more detail with reference to Examples.

[0027]

【Example】

(Example 1) FIG. 1 is a cross-sectional view of a coin-type battery showing an example of a test cell used for performance evaluation of an electrode active material of a non-aqueous electrolyte secondary battery according to the present invention.

In the figure, reference numeral 1 is a counter electrode case which also serves as a counter electrode terminal, which is formed by drawing a stainless steel plate having Ni plated on one outer surface. Reference numeral 2 denotes a counter electrode current collector made of a stainless steel net, which is spot-welded to the counter electrode case 1.

The counter electrode 3 is formed by punching an aluminum plate having a predetermined thickness to a diameter of 15 mm, fixing it to the counter electrode current collector 2, and pressing a lithium foil having a predetermined thickness punching to a diameter of 14 mm on the aluminum foil. Reference numeral 7 denotes a working electrode case made of stainless steel whose outer surface is plated with Ni, and also serves as a working electrode terminal.

Numeral 5 is a working electrode composed of an active material according to the present invention described later or a comparative active material according to a conventional method, which is a working electrode current collector composed of a conductive adhesive containing carbon as a conductive filler. It is adhered to the working pole case by the body 6. Reference numeral 4 is a separator made of a polypropylene porous film, which is impregnated with an electrolytic solution.

Numeral 8 is a gasket mainly composed of polypropylene, which is interposed between the counter electrode case 1 and the working electrode case 7 to maintain the electrical insulation between the counter electrode and the working electrode, and at the same time the working electrode case opening edge. The battery contents are hermetically sealed by being bent and crimped inward.
The electrolytes are propylene carbonate and ethylene carbonate.
And the volume ratio of 1,2-dimethoxyethane 1: 1: 2
1 mol / l of lithium perchlorate LiClO ₄ in the mixed solvent
What was melt | dissolved was used. Battery size is 20m outside diameter
m and the thickness was 1.6 mm.

The working electrode 5 was manufactured as follows. Commercially available manganese monoxide MnO was pulverized and sized by an automatic mortar to have a particle size of 53 μm or less, and used as the active material 1 according to the present invention, and graphite was used as a conductive agent and crosslinked acrylic acid resin or the like was used as a binder. The working electrode mixture is mixed at a weight ratio of 65:20:15, and then the working electrode mixture is mixed with 2 ton.
A pellet having a diameter of 15 mm, a thickness of 0.3 mm and a pressure of 10 cm2 / cm ² was pressure-molded and dried under reduced pressure at 200 ° C. for 10 hours to obtain a working electrode.

For comparison, the same graphite as that used for the above conductive material was used as the active material (abbreviated as active material 4) instead of the above active material 1 according to the present invention. A similar electrode (working electrode for comparison) was prepared in the same manner as the working electrode of the invention. The battery thus produced was left to stand for one week at room temperature and then subjected to the charge / discharge test described below. By this aging, the lithium-aluminum laminated electrode of the counter electrode is sufficiently alloyed by touching the non-aqueous electrolytic solution in the battery, and the lithium foil becomes substantially all Li-Al alloy, so that the battery voltage is As compared with the case where metallic lithium was used alone as the counter electrode, the value was reduced by about 0.4 V and stabilized.

The batteries thus produced will be abbreviated as batteries 1 and 4 in correspondence with the active materials 1 and 4 of the working electrodes used. These batteries 1 and 4 were charged at a constant current of 1 mA (the current direction in which a battery reaction occurs in which lithium ions are occluded in the working electrode from the electrolyte), the final voltage of −0.
4V, end voltage of discharge (current direction of battery reaction in which lithium ions are released from working electrode into electrolyte) 2.5V
FIG. 2 shows the discharge characteristic at the third cycle when the charge / discharge cycle was performed under the conditions of, and FIG. 3 shows the charge characteristic. The cycle characteristics are shown in FIG.

The charging / discharging cycle was started from charging. As is clear from FIGS. 2 to 4, it can be seen that the battery 1 according to the present invention has a significantly higher charge / discharge capacity than the comparative battery 4, and the reversible charge / discharge region is significantly expanded. Further, the decrease in discharge capacity (cycle deterioration) due to repeated charging and discharging is extremely small. Further, it can be seen that the difference between the operating voltages of charging and discharging is extremely small over the entire charging / discharging region, the polarization (internal resistance) of the battery is extremely small, and large-current charging / discharging is easy.

Example 2 Instead of the active material 1 of Example 1, commercially available titanium monoxide TiO was pulverized and sized to a particle size of 53 μm or less, and the active material of the working electrode (active material 2 according to the present invention). Used as. A battery 2 was prepared in the same manner as the battery 1 of Example 1 except for the active material of the working electrode.

With respect to the battery 2 thus obtained and the above-mentioned comparative battery 4, the end voltage of charging at a constant current of 1 mA-
A charge / discharge cycle test was performed under the conditions of 0.4 V and a discharge end voltage of 2.5 V. The discharge characteristics at the third cycle at this time are shown in FIG. 5, the charge characteristics are shown in FIG. 6, and the cycle characteristics are shown in FIG.

As is clear from the figure, the battery 2 of this embodiment is
It can be seen that the battery 1 as well as the battery 1 of Example 1 according to the present invention has excellent charge and discharge characteristics. That is, the opposite Li
-Lithium ions are released from the Al alloy into the electrolyte,
This lithium ion moves in the electrolyte and undergoes an electrode reaction with the active material 2 of the working electrode, and the active material 2 electrochemically occludes lithium ions to form a lithium-containing composite oxide Li _x T.
iO generates.

Next, during discharge, lithium ions are released from the composite oxide into the electrolyte, move in the electrolyte, and are occluded in the Li-Al alloy of the counter electrode, so that stable charge and discharge can be performed repeatedly. Here, the active material 2 is a composite oxide Li _x Ti containing lithium after the first charge.
After O is generated, in a subsequent discharge-charge cycle, a lithium-containing composite oxide Li _x TiO is formed except when it is completely discharged.

Example 3 Commercially available zinc monoxide ZnO was pulverized and sized to a particle size of 53 μm or less and used as the active material (active material 3 according to the present invention) of the working electrode. A battery 3 was prepared in the same manner as the battery 1 of Example 1 except for the active material of the working electrode. The battery 3 thus obtained and the above-mentioned comparative battery 4 were subjected to a charge / discharge cycle test under the conditions of a constant current of 1 mA and an end voltage of charge of −0.4 V and an end voltage of discharge of 2.5 V. The discharge characteristics in the first cycle at this time are shown in FIG. 8, and the charge characteristics are shown in FIG.

As is apparent from the figure, the battery 3 of this embodiment is
It can be seen that the batteries 1 and 2 according to the present invention of Examples 1 and 2 have excellent charge and discharge characteristics. As is clear from FIGS. 8 to 9, it is understood that the battery 3 according to the present invention has a significantly larger charge / discharge capacity and the reversible charge / discharge region is significantly expanded as compared with the comparative battery 4. Further, it can be seen that the difference in operating voltage between charging and discharging is extremely small over the entire charging / discharging region, the polarization (internal resistance) of the battery is extremely small, and large current charging / discharging is easy.

Further, the active materials 1, 2, and 3 of the batteries 1, 2 and 3 according to the present invention are 1.1 to the Li-Al alloy electrode.
Similar to or higher than the noble potential region of 2.5 V (corresponding to about 1.5 to 2.9 V for metallic lithium), -0.4 to +1.1 V (about 0 for metallic lithium).
Since it has a large charge / discharge capacity in a base potential region (corresponding to ~ 1.5 V), it can be seen that it is not only used as a positive electrode active material of a non-aqueous electrolyte secondary battery but also particularly excellent as a negative electrode active material. .

In the examples, only the case of the lithium-aluminum alloy was shown as the counter electrode, but the present invention is not limited to the examples, and as described above, metallic lithium, lithium and Zn, Sn, Pb, Alloys with other metals such as Bi, lithium insertion compounds such as carbon or MoO ₂ , WO ₂ , Fe ₂ O ₃ , and conductive polymers capable of doping lithium ions such as polyacetylene, polypyrrole, and polyacene. A negative electrode using a material capable of inserting and extracting lithium as an active material, and TiS
₂ , metal chalcogenides such as MoS ₂ and NbSe ₃ , Mn
O ₂ , MoO ₃ , V ₂ O ₅ , Li _X CoO ₂ , Li _X NiO ₂ ,
An active material that can store and release lithium cations and / or anions, such as metal oxides such as Li _x Mn ₂ O ₄ , conductive polymers such as polyaniline, polypyrrole, polyparaphenylene, and polyacene, graphite intercalation compounds, etc. It goes without saying that the positive electrode as described above can be used as a counter electrode in combination with the electrode according to the present invention.

[0044]

As described in detail above, according to the present invention, a metal selected from Mn, Ti, and Zn and lithium are used as the active material of at least one of the negative electrode and the positive electrode of the non-aqueous electrolyte secondary battery. And a novel active material composed of a composite oxide of Li _x MO, which is capable of reversibly occluding and releasing lithium ions by charging and discharging, that is, the charging and discharging capacity is extremely large, and the polarization of charging and discharging is small. In addition, it is possible to charge and discharge with a large current, and it is possible to obtain an extremely stable battery having a long cycle life with almost no deterioration such as decomposition or crystal collapse due to overcharge and overdischarge. Further, in particular, when the active material according to the present invention is used as a negative electrode active material, it has an excellent effect such that a battery having high voltage and high energy density can be obtained.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an example of the structure of a battery implemented in the present invention.

FIG. 2 is an explanatory diagram showing a comparison of the discharge characteristics at the third cycle between the battery according to the present invention and the conventional battery.

FIG. 3 is an explanatory diagram showing a comparison of the charging characteristics in the third cycle between the battery according to the present invention and the conventional battery.

FIG. 4 is an explanatory diagram showing a comparison of cycle characteristics of a battery according to the present invention and a conventional battery.

FIG. 5 is an explanatory diagram showing a comparison of the discharge characteristics at the third cycle between the battery according to the present invention and the conventional battery.

FIG. 6 is an explanatory diagram showing a comparison of the charging characteristics in the third cycle between the battery according to the present invention and the conventional battery.

FIG. 7 is an explanatory diagram showing a comparison of cycle characteristics of a battery according to the present invention and a conventional battery.

FIG. 8 is an explanatory diagram showing a comparison of the discharge characteristics in the first cycle between the battery according to the present invention and the conventional battery.

FIG. 9 is an explanatory diagram showing a comparison of the charging characteristics in the first cycle between the battery according to the present invention and the conventional battery.

[Explanation of symbols]

 1 counter electrode case 2 counter electrode current collector 3 counter electrode 4 separator 5 working electrode 6 working electrode current collector 7 working electrode case 8 gasket

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Seiji Yahagi 6-31-1, Kameido, Koto-ku, Tokyo Seiko Denshi Kogyo Co., Ltd. (72) Kensuke Tahara 5-30, Nishitaga, Taihaku-ku, Sendai City, Miyagi Prefecture No. 1 in Seiko Electronic Components Co., Ltd. (72) Inventor Hideki Ishikawa 5-30-1 Nishitaga, Taichiro-ku, Sendai City, Miyagi Prefecture Seiko Electronic Components Co., Ltd.

Claims (1)

[Claims] 1. In a non-aqueous electrolyte secondary battery comprising at least a negative electrode, a positive electrode and a lithium ion conductive non-aqueous electrolyte, a composition formula Li _x MO is used as an active material of at least one of the negative electrode and the positive electrode. , M is at least one metal selected from Mn, Ti, and Zn, and a composite oxide of metal M and lithium Li represented by 0 ≦ x is used. Next battery.