WO2013108841A1

WO2013108841A1 - Non-aqueous electrolyte secondary cell containing scavenger

Info

Publication number: WO2013108841A1
Application number: PCT/JP2013/050818
Authority: WO
Inventors: 充康今▲崎▼
Original assignee: 株式会社カネカ
Priority date: 2012-01-19
Filing date: 2013-01-17
Publication date: 2013-07-25
Also published as: TW201336145A; JPWO2013108841A1

Abstract

The present invention provides a non-aqueous electrolyte secondary cell that has excellent charge-discharge cycle characteristics and suppresses gas generation due to the existence in the cell of a scavenger comprising metal acting at a specified potential. The non-aqueous electrolyte secondary cell has a positive electrode, a negative electrode, and a non-aqueous electrolyte layer interposed between the positive electrode and the negative electrode. The scavenger is present between the positive electrode and the negative electrode in a state not contacting either the positive electrode or the negative electrode and contacting the non-aqueous electrolyte, and the scavenger contains an alkali metal, alkali earth metal or other metal having an oxidation-reduction potential that is no greater than the negative-electron action potential, or an intermetallic compound or alloy.

Description

Non-aqueous electrolyte secondary battery including a trap

The present invention relates to a nonaqueous electrolyte secondary battery, and more particularly to improvement of charge / discharge cycle characteristics of the nonaqueous electrolyte secondary battery. This application claims priority based on Japanese Patent Application No. 2012-009346.

Secondary batteries such as lithium ion secondary batteries are now widely used as power sources for mobile devices. In particular, lithium ion secondary batteries have higher energy density than existing nickel-cadmium storage batteries and nickel-hydrogen storage batteries, and are therefore expected to be used for large power supplies such as electric vehicles and power storage.
Since a lithium ion secondary battery is discharged with use, it must be charged after discharging. In this way, the lithium ion secondary battery is repeatedly charged and discharged during use. There is a property that the battery capacity decreases with this charge / discharge cycle, which is referred to as deterioration of the “charge / discharge cycle characteristics”. This tendency is particularly remarkable at high temperatures.

Therefore, for example, in Patent Document 1, in order to suppress deterioration of charge / discharge cycle characteristics at high temperatures, a trapping substance that captures impurity ions such as cations and fluoride ions other than lithium ions generated inside the battery is used as a separator. By holding on the surface, the surface of the positive electrode or the negative electrode or the inside thereof, the cation or fluoride ion causing the battery deterioration is prevented from adhering to the negative electrode active material particles. As an example of the trapping substance, Patent Document 1 mentions activated carbon having a specific surface area of 1000 m 2 / g or a pore volume of 0.1 cc / g or more, and also includes an alkaline earth metal oxide.

JP 2000-77103 A

However, in the structure described in Patent Document 1, the electrode material has a higher potential than carbon (hereinafter, when the potential is “high, low”, it is called “high” when it increases in the positive potential direction, and in the negative potential direction. When a negative electrode active material that operates at a low level is called “low”, even if the aforementioned trapping material is used, the trapping material is used before impurity ions such as cations or fluoride ions reach the negative electrode. There is a problem that it is difficult to obtain the captured effect.

Moreover, if activated carbon with a large specific surface area is used as described in Patent Document 1, when a kneaded material containing an electrode active material, activated carbon, and solvent is applied to a current collector, the kneading occurs with an increase in the amount of solvent absorbed by the activated carbon. The viscosity of the product is likely to increase, and the coating workability is reduced. When the alkaline earth metal oxide is held on the negative electrode, since the oxide is an insulator, the conductive performance of the negative electrode active material is lowered, and the battery capacity per unit weight of the electrode may be reduced.

In view of the above-mentioned circumstances, the present inventor has found that a non-aqueous electrolyte secondary battery excellent in charge / discharge cycle characteristics can be obtained by making a capture body made of metal that operates at a specific potential exist in the battery. The present invention has been completed. Furthermore, the present invention has been completed by finding the effect of suppressing gas generation due to the presence of the trapping body.

The nonaqueous electrolyte secondary battery of the present invention includes a positive electrode, a negative electrode, and a nonaqueous electrolyte layer interposed between the positive electrode and the negative electrode. The positive electrode and the negative electrode are interposed between the positive electrode and the negative electrode. A trapping body containing a metal, an intermetallic compound, or an alloy having a redox potential equal to or lower than the negative electrode operating potential in a state where it is not in contact with any of the above and in contact with a nonaqueous electrolyte is interposed.
According to this structure, since the oxidation-reduction potential of the capturing body is equal to or less than the operating potential of the negative electrode, impurity ions moving from the positive electrode to the negative electrode are easily captured by the capturing body before reaching the negative electrode, and charge / discharge cycles are performed. Even if it repeats, the nonaqueous electrolyte secondary battery which can reduce deterioration of a battery characteristic can be obtained. The requirement of “a state in which neither the positive electrode nor the negative electrode is in contact” is a requirement that prevents short-circuiting between electrodes via a capturing body in a battery and that the supplement body and the positive electrode or the supplement body This is to prevent generation of a local battery formed between the battery and the negative electrode.

It is preferable to select an alkali metal, an alkali intermetallic compound, or an alloy as the metal contained in the capturing body. The redox potential of the alkali metal is a large value of about −3 V, and the above-described impurity ion trapping effect can be obtained efficiently.
The alkali metal may be lithium or sodium.
As the metal contained in the capturing body, an alkaline earth metal, an alkaline earth intermetallic compound, or an alloy may be selected. The redox potential of the alkaline earth metal is also a value close to −3 V, and the impurity ion trapping effect described above is easily obtained.

As a form in which the capturing body is disposed in the non-aqueous electrolyte secondary battery, it may be dispersed in the non-aqueous electrolyte solution. Further, when a porous film serving as a separator is interposed between the positive electrode and the negative electrode, the capturing body may be present in the porous film. You may arrange | position a capturing body in a gel-like nonaqueous electrolyte. In either case, impurity ions moving from the positive electrode to the negative electrode can be efficiently captured by the trapping body, charge / discharge cycle characteristics can be improved, and gas generation can be suppressed.

For the negative electrode, it is preferable to use a negative electrode active material that operates at −2.7 V or more and −1.0 V or less with respect to a standard hydrogen electrode. When such a negative electrode active material is used, for example, when lithium metal is used as the capturing body, it can be operated with a potential difference of 0.3 V or more and 2.0 V or less with respect to the oxidation-reduction potential (−3 V) of the lithium metal.
In particular, lithium titanium oxide or titanium oxide is preferably used for the negative electrode active material constituting the negative electrode.

Further, as the positive electrode active material constituting the positive electrode, it is preferable to use lithium manganese oxide or a material obtained by substituting a part of manganese of lithium manganese oxide with a different metal or a different material.
The above-described or further advantages, features, and effects of the present invention will be made clear by the following description of embodiments with reference to the accompanying drawings.

It is sectional drawing which shows the structure of the nonaqueous electrolyte secondary battery 1 which concerns on embodiment of this invention. It is a disassembled perspective view of the nonaqueous electrolyte secondary battery 1 of FIG. FIG. 3 is a perspective view showing an example in which a capturing body 9 is formed in a plurality of elongated foil shapes and fitted in a lattice shape inside a frame 10. 3 is a plan view showing an example in which a capturing body 9 is formed into a plurality of elongated foil shapes and is woven into a net shape inside a frame 10. FIG. It is a schematic circuit diagram of the apparatus which performs a charging / discharging cycle test. The graph which plotted the battery capacity maintenance factor of Example 1 and Comparative Example 1 with respect to the number of charging / discharging cycles is shown.

Embodiments of the present invention will be described below. The scope of the present invention is defined by the scope of the claims, and is intended to include any modifications within the scope and meaning equivalent to the scope of the claims.
<Structure of non-aqueous electrolyte secondary battery>
FIG. 1 is a cross-sectional view showing an internal structure of a nonaqueous electrolyte secondary battery 1 according to an embodiment of the present invention, and FIG. 2 is an exploded perspective view. The nonaqueous electrolyte secondary battery 1 includes a positive electrode current collector 2, a negative electrode current collector 4, and a nonaqueous electrolyte layer 3 interposed between the positive electrode and the negative electrode. The positive electrode current collector 2 and the negative electrode current collector 4 face each other and are arranged so as to overlap in plan view. A positive electrode active material 5 is formed on a surface of the positive electrode current collector 2 facing the negative electrode current collector 4, and a negative electrode active material is formed on the surface of the negative electrode current collector 4 facing the positive electrode current collector 2. Substance 6 is formed. An aggregate of the positive electrode current collector 2 and the positive electrode active material 5 is referred to as a “positive electrode”, and an aggregate of the negative electrode current collector 4 and the negative electrode active material 6 is referred to as a “negative electrode”.

Between the positive electrode active material 5 and the negative electrode active material 6,

porous membrane separators

7a and 7b are interposed in a two-stage configuration. The inside of the

separators

7a and 7b, the gap between the separator 7a and the positive electrode active material 5, and the gap between the separator 7b and the negative electrode active material 6 are impregnated with a non-aqueous electrolyte solution responsible for ion conduction such as lithium ions. is doing.
Further, in order to prevent contact between adjacent electrodes and penetration of moisture, oxygen, etc. from the outside, a frame is formed so as to close between the peripheral part of the positive electrode current collector 2 and the peripheral part of the negative electrode current collector 4. Insulating sealing material 8 is formed.

In the non-aqueous electrolyte secondary battery 1, the positive electrode current collector 2 and the negative electrode current collector 4 are not in contact with either the positive electrode current collector 2 or the negative electrode current collector 4. In addition, an alkali metal, an alkali intermetallic compound or alloy, or an alkaline earth metal, alkaline earth intermetallic compound or alkaline earth metal alloy is interposed in contact with the nonaqueous electrolyte. This alkali metal, alkali metal intermetallic compound or alloy, or alkaline earth metal, alkaline earth intermetallic compound, or alkaline earth metal alloy is referred to as “capturing body” 9 in this specification. Examples of the alkali metal include lithium, sodium, and potassium. Examples of alkaline earth metals include magnesium and calcium.

Hereinafter, each element which comprises the nonaqueous electrolyte secondary battery 1 of this invention is demonstrated in detail.
<Captured body>
The structure for providing the capturing body 9 of the present invention in the nonaqueous electrolyte secondary battery 1 is not limited. For example, the capturing body 9 may be formed as a plurality of particles and dispersed in the nonaqueous electrolyte solution. In this way, when the capturing body 9 is formed as a plurality of particles and dispersed in the nonaqueous electrolyte solution, one particle must not contact both electrodes simultaneously.

The shape of each particle may be a sphere, ellipsoid, cylinder, needle, cuboid, polyhedron, or the like. Since the dimensional ratio is not limited in the case of a rectangular parallelepiped, the shape may be a plate piece or a foil piece. When the particles are dispersed in the nonaqueous electrolyte solution, the volume density of the particles is preferably in the range of 2 to 20 parts by volume with respect to 100 parts by volume of the nonaqueous electrolyte solution. If it exceeds this range, the movement of the electrolyte solution and ions will be inhibited, and if it falls below this range, the function of trapping impurities will be reduced, which is not preferable.

As shown in FIGS. 2 and 3, the capturing body 9 is provided with a frame 10, and the capturing body 9 is formed in a plurality of elongated foil shapes and arranged in the same direction inside the frame 10 in a lattice shape. It may be a structure in which the frame 10 is inserted and arranged between the plurality of

separators

7a and 7b. The number of

separators

7a and 7b is not limited as long as it is 2 or more. For example, one stage of the planar capturing body 9 may be inserted between the two stages of

separators

7a and 7b, or two stages of the planar capturing body 9 may be inserted between the three stages of separators.

The shape of the capturing body 9 is preferably a shape having a gap such as a lattice shape or a mesh shape in plan view. However, it is not preferable to form a solid flat surface with no gaps because it interferes with the transport of the substance carrying the charge.
FIG. 3 is a perspective view showing the structure of the capturing body 9 formed in a lattice shape. The shape of the grating is not limited, and may be a grating extending in two vertical and horizontal directions, or may be a grating arranged in only one direction as shown in FIG.

FIG. 4 is a perspective view showing the structure of the capturing body 9 formed in a mesh shape. The mesh shape in this case is not limited, and may be a mesh obtained by knitting a vertical capturing body 9 and a horizontal capturing body 9 at right angles as shown in FIG. It may be knitted.
The shape of each bar or elongated body constituting the lattice or mesh may be a circle, an ellipse, a rectangle, or a polygon. Since the dimensional ratio is not limited when the cross section is rectangular, it may be plate-shaped or foil-shaped. However, if the thickness t of the rod or the elongated body is too thick, further rolling of the battery occurs due to compression from above and below during battery formation. Therefore, in order to prevent this rolling, the thickness t is preferably 100 μm or less.

The area ratio of the gap to the whole when the rod or the long body is viewed in plan is defined as the hole area ratio S of the capturing body 9.
When the width of the rod or long body in plan view is w and the arrangement pitch is p, the aperture ratio S of the capturing body 9 is S = (p−w) / p in the case of the vertical lattice of FIG. Can be calculated. In the case of the mesh in FIG. 4, it can be calculated by S = (p−w) 2 / p 2. For example, in the case of the vertical lattice of FIG. 3, if the width w = 1 mm and the arrangement pitch p = 10 mm, the aperture ratio S = 0.9.

The open area ratio S is preferably selected to be in the range of 0.7 to 0.98. If the porosity S is smaller than this, the transport of the substance carrying the charge is hindered. If the porosity S is larger than this, the function of trapping impurities is lowered, which is not preferable.
These rod-shaped or elongated capturing bodies 9 are arranged in a frame 10 or a lattice shape in a frame 10. By attaching the capturing body 9 to the frame 10, the handling of the capturing body 9 becomes convenient and the assembly of the battery becomes easy.

The material of the frame 10 needs to be a substance that does not react with the non-aqueous electrolyte solution, but the material is arbitrary as long as it is satisfied. For example, a frame made by molding a strong material such as stainless steel, a frame made by molding an alkali metal, an alkali intermetallic compound or alloy, an alkaline earth metal, an alkaline earth intermetallic compound, or an alkaline earth metal And a frame made by molding the alloy. If stainless steel or the like is used, the strength can be easily secured and the handling becomes convenient. If produced using an alkali metal or alkaline earth metal, the frame itself can have the same trapping action as the trap 9.

The width of the frame 10 is preferably 3 mm to 5 mm. If it is smaller than 3 mm, handling becomes difficult, and if it is larger than 5 mm, the frame 10 itself may cover the positive electrode or the negative electrode, which may impede the transport of the substance carrying the charge. Moreover, the

separators

7a and 7b may be too large. The shape of the frame 10 is not limited to a square frame as shown in FIGS. 3 and 4, and the shape is arbitrary as long as it is a member having some structure that supports the capturing body 9. For example, an annular frame may be used. A member having a partially opened structure such as a letter “U” or “C” may also be used.

Further, instead of providing the capturing body 9 on the frame 10, as the capturing body 9, an alkali metal, an alkali intermetallic compound or alloy, or an alkaline earth metal, an alkaline earth intermetallic compound or alloy is formed into a plate having a thickness t. In order to obtain a predetermined aperture ratio S, a hole such as a circle, an ellipse, a triangle, a rectangle, or a polygon may be punched in the hole.
When the capturing body 9 is formed from particles, a binder may be used to facilitate the forming. The binder is not particularly limited, and for example, at least one selected from the group consisting of polyvinylidene fluoride (PVdF), polytetrafluoroethylene (PTFE), styrene-butadiene rubber, polyimide, and derivatives thereof can be used.

Further, as described above, the capturing body 9 of the present invention may be a “single unit” of an alkali metal, an alkali intermetallic compound or alloy, or an alkaline earth metal, an alkaline earth intermetallic compound or alloy. In addition, the following structure may be used. That is, particles, lattices, nets, plates before punching, etc. are composed of a substrate of a different metal or a different material, and on the surface of the different metal or different material substrate, an alkali metal, an alkali intermetallic compound or alloy, or An alkaline earth metal, an alkaline earth intermetallic compound or alloy may be formed into a thin film by a technique such as coating, plating, vapor deposition, or sputtering. The plating method is not limited to electrolytic plating or electroless plating. Here, a different metal or a different substance means a metal or substance other than an alkali metal, an alkali intermetallic compound or alloy, or an alkaline earth metal, an alkaline earth intermetallic compound or alloy.

In addition, as a modified example of the structure of the nonaqueous electrolyte secondary battery 1 according to the embodiment of the present invention, it is not always necessary to use the

independent separators

7a and 7b unless the positive electrode and the negative electrode are in direct contact. That is, a structure without the

separators

7a and 7b is also conceivable. In this case, a gel-like material may be used as the nonaqueous electrolyte in order to prevent contact between the positive electrode and the negative electrode. Thus, when using a gel-like nonaqueous electrolyte, when forming the capturing body 9 of the present invention as a plurality of particles, it is dispersedly arranged inside the gel-like nonaqueous electrolyte. Further, when the planar capturing body 9 is inserted and arranged, it is inserted and arranged in the gel-like nonaqueous electrolyte so as not to contact either the positive electrode or the negative electrode.

<Negative electrode>
The negative electrode used in the nonaqueous electrolyte secondary battery of the present invention is composed of at least a negative electrode active material or a negative electrode active material and a current collector. The negative electrode active material may contain a conductive additive and a binder as necessary.
It is preferable to use a material that operates at −2.7 V or more and −1.0 V or less with respect to a standard hydrogen electrode as the negative electrode active material. Although such materials are not particularly limited, for example, transition metal-containing oxides such as molybdenum oxide, niobium oxide, manganese oxide, lithium manganese oxide, titanium oxide, lithium titanium oxide, nickel nitride, manganese nitride, iron nitride, etc. Transition metal nitrides, transition metal sulfides such as nickel sulfide and manganese sulfide, phosphides such as nickel phosphide, manganese phosphide and iron phosphide and phosphorus alone, fluorides such as iron fluoride and nickel fluoride, alkali metals And / or at least one selected from the group consisting of metals that form alloys with alkaline earth metals can be used.

A binder may be used to form the negative electrode of the present invention. The binder is not particularly limited, and for example, at least one selected from the group consisting of polyvinylidene fluoride (PVdF), polytetrafluoroethylene (PTFE), styrene-butadiene rubber, polyimide, and derivatives thereof can be used. The binder is preferably dissolved or dispersed in a non-aqueous solvent or water from the viewpoint of easy production of the negative electrode. The non-aqueous solvent is not particularly limited, and examples thereof include N-methyl-2-pyrrolidone (NMP), dimethylformamide, dimethylacetamide, methyl ethyl ketone, methyl acetate, ethyl acetate, and tetrahydrofuran. You may add a dispersing agent and a thickener to these.

In the present invention, the amount of the binder contained in the negative electrode is preferably 1 part by weight or more and 30 parts by weight or less, more preferably 1 part by weight or more and 15 parts by weight or less with respect to 100 parts by weight of the negative electrode active material. If it is this range, the adhesiveness of a negative electrode active material and a conductive support material will be maintained, and adhesiveness with a collector can fully be acquired.
The negative electrode of the present invention may contain a conductive additive as necessary. Although it does not specifically limit as a conductive support material, A carbon material and / or a metal microparticle are preferable. Examples of the carbon material include natural graphite, artificial graphite, vapor-grown carbon fiber, carbon nanotube, acetylene black, ketjen black, and furnace black. Examples of the metal fine particles include copper, aluminum, nickel, and an alloy containing at least one of these. Further, the fine particles of inorganic material may be plated. These carbon materials and metal fine particles may be used alone or in combination of two or more.

In the present invention, the amount of the conductive additive contained in the negative electrode is preferably 1 part by weight or more and 30 parts by weight or less, more preferably 1 part by weight or more and 15 parts by weight or less with respect to 100 parts by weight of the negative electrode active material. . If it is a range, the electroconductivity of a negative electrode will be ensured.
Examples of the material of the current collector used for the negative electrode of the nonaqueous electrolyte secondary battery of the present invention include copper, aluminum, nickel, an alloy containing at least one of these, or a conductive polymer. Examples of the shape include a foil shape, a mesh shape, a punching shape, an expanded shape, and a foam structure.

Here, the mesh shape is a woven or unemployed cloth made of metal or conductive polymer fibers. The thickness of the fiber is preferably 50 μm or more and 2000 μm or less. When the thickness is less than 50 μm, the strength of the current collector is weak. Therefore, when the active material mixture is supported on the current collector, the current collector tends to be easily broken. On the other hand, when a fiber thicker than 2000 μm is used, the opening becomes too large to make the porosity described later, and it tends to be difficult to hold the active material mixture by the mesh.

The punching shape is a plate in which holes such as a circle, a rectangle, or a hexagon are formed, and a metal made of metal is punching metal. The porosity corresponds to the hole area ratio, which is determined by the hole diameter and bone ratio, hole shape, and hole arrangement. The shape of the hole is not particularly limited, but from the viewpoint of increasing the open area ratio, a round hole 60 ° staggered type and a square hole staggered / parallel type are preferable.
The expanded shape is a staggered cut made on a plate and stretched to form a mesh. Expanded metal is made of metal. The porosity corresponds to the hole area ratio, which is determined by the hole diameter and bone ratio, the hole shape, and the hole arrangement.

The foam structure has a three-dimensional network structure like a sponge and has continuous pores. The structure is determined by the pore size and porosity. The shape and diameter of the continuous holes are not particularly limited, but a structure having a high specific surface area is preferable.
The metal used in the current collector of the present invention may be stable between negative electrode operating voltages, preferably copper and its alloys when the operating potential is −2.3 V or lower, and aluminum and its alloys when −2.3 V or higher. Is preferred.

The negative electrode of the present invention is produced by, for example, supporting a negative electrode mixture comprising a negative electrode active material, a conductive additive, and a binder on a current collector. It is preferable to prepare a negative electrode by preparing a slurry with a binder and a solvent, filling and applying the obtained slurry to the pores of the current collector and the outer surface thereof, and then removing the solvent. Alternatively, the mixture of the negative electrode active material, the conductive additive and the binder may be supported on the current collector as it is without being dispersed in the solvent.

The slurry is not particularly limited, but it is preferable to use a ball mill, a planetary mixer, a jet mill, or a thin film swirling mixer because the negative electrode active material, the conductive additive, the binder, and the solvent can be mixed uniformly. Although the production of the slurry is not particularly limited, it may be produced by mixing the negative electrode active material, the conductive additive, and the binder and then adding a solvent, or the negative electrode active material, the conductive additive, the binder, and the solvent together. You may mix and produce.

The solid content concentration of the slurry is preferably 30 wt% or more and 80 wt% or less. If it is less than 30 wt%, the viscosity of the slurry tends to be too low, whereas if it is higher than 80 wt%, the viscosity of the slurry tends to be too high, and it may be difficult to form an electrode described later.
The solvent used for the slurry is preferably a non-aqueous solvent or water. The non-aqueous solvent is not particularly limited, and examples thereof include N-methyl-2-pyrrolidone (NMP), dimethylformamide, dimethylacetamide, methyl ethyl ketone, methyl acetate, ethyl acetate, and tetrahydrofuran. Moreover, you may add a dispersing agent and a thickener to these.

The method for supporting the negative electrode mixture on the current collector is not particularly limited, but for example, a method of removing the solvent after applying the slurry with a doctor blade, die coater, comma coater or the like, or a method of removing the solvent after adhering to the current collector by spraying. A removal method and a method of removing the solvent after impregnating the current collector in the slurry are preferable. The method for removing the solvent is preferable because it is easy to dry using an oven or a vacuum oven. Examples of the atmosphere include room temperature or high temperature air, an inert gas, and a vacuum state. The negative electrode may be formed before or after forming the positive electrode described later. When the negative electrode active material, conductive additive and binder are not dispersed in the solvent, the negative electrode active material, conductive additive and binder can be mixed uniformly, so use a ball mill, planetary mixer, jet mill, or thin film swirl mixer. After preparing the mixture, it is preferable to carry the mixture on the current collector. The method of supporting the mixture on the current collector is not particularly limited, and a method of pressing the mixture after it is packed on the current collector is preferable. The press may be heated. Moreover, you may compress a negative electrode using a roll press machine etc. after negative electrode preparation. The electrode may be compressed before or after the above-described positive electrode is formed.

<Positive electrode>
The positive electrode used in the nonaqueous electrolyte secondary battery of the present invention is composed of at least a positive electrode mixture, or a positive electrode mixture and a current collector. A positive electrode mixture contains a positive electrode active material and a binder at least, and a conductive support material as needed.
The positive electrode active material is not particularly limited, but a composite oxide, composite nitride, composite containing an alkali metal and / or an alkaline earth metal having an operating potential of −0.2 V to 2.2 V with respect to a standard hydrogen electrode. At least one selected from the group consisting of fluoride, composite sulfide, composite selenide and the like can be used.

A binder may be used for the positive electrode active material. What was illustrated by the binder used for the negative electrode mixture mentioned above is applicable similarly. The binder is preferably dissolved or dispersed in a non-aqueous solvent or water from the viewpoint of easy production of the positive electrode. As the non-aqueous solvent, those exemplified above for the non-aqueous solvent can be similarly applied. You may add a dispersing agent and a thickener to these.
The positive electrode of the present invention may contain a conductive additive as necessary. Although it does not specifically limit as a conductive support material, A carbon material or a metal microparticle is preferable. Examples of the carbon material include the same carbon materials that can be contained in the negative electrode. Examples of the metal fine particles include aluminum and aluminum alloys. Further, the fine particles of inorganic material may be plated. These carbon materials and metal fine particles may be used alone or in combination of two or more.

In the present invention, the amount of the conductive additive contained in the positive electrode is preferably 1 part by weight or more and 30 parts by weight or less, more preferably 1 part by weight or more and 15 parts by weight or less with respect to 100 parts by weight of the positive electrode active material. . If it is a range, the electroconductivity of a positive electrode will be ensured. Moreover, adhesiveness with a binder is maintained and sufficient adhesiveness with a collector can be obtained. On the other hand, when a larger amount of conductive aid than 30 parts by weight is used, the volume occupied by the conductive aid increases and the energy density tends to decrease.

As the current collector used for the positive electrode of the nonaqueous electrolyte secondary battery of the present invention, those exemplified for the current collector used for the negative electrode active material and those in the form of a foil can be similarly applied.
The positive electrode of the present invention is produced by, for example, supporting a positive electrode active material, a conductive additive, and a positive electrode active material of a binder on a current collector. A method is preferred in which a slurry is prepared with a binder and a solvent, and the positive electrode is prepared by removing the solvent after filling and applying the obtained slurry to the pores and the outer surface of the current collector. Alternatively, the mixture of the positive electrode active material, the conductive additive and the binder may be supported on the current collector as it is without being dispersed in the solvent.

In the preparation of the negative electrode, the method for preparing the slurry, the solid content concentration of the slurry, the solvent used for the slurry, the method for supporting the active material layer on the current collector, and the compression of the electrode can be similarly applied to the preparation of the positive electrode. .
<Capacity ratio and area ratio of negative electrode to positive electrode>
The ratio of the electric capacity of the positive electrode and the electric capacity of the negative electrode in the nonaqueous electrolyte secondary battery of the present invention preferably satisfies the following formula (1).

0.7 ≦ B / A ≦ 1.3 (1)
However, in Formula (1), A shows the electric capacity per 1 cm <2> of positive electrodes, and B shows the electric capacity per 1 cm <2> of negative electrodes.
When B / A is less than 0.7, the potential of the negative electrode may become the deposition potential of alkali metal and / or alkaline earth metal during overcharge, while B / A is greater than 1.3. Side reactions may occur because there are many negative electrode active materials not involved in the battery reaction.

Although the area ratio of the positive electrode to the negative electrode in the nonaqueous electrolyte secondary battery of the present invention is not particularly limited, it is preferable to satisfy the following formula (2).
1 ≦ D / C ≦ 1.2 (2)
(However, C represents the area of the positive electrode, and D represents the area of the negative electrode.)
When D / C is less than 1, for example, when B / A = 1 as described above, the capacity of the negative electrode is smaller than that of the positive electrode, so that the potential of the negative electrode is higher than that of the alkali metal and / or alkaline earth metal during overcharge. There is a risk of deposition potential. On the other hand, if D / C is greater than 1.2, the negative electrode active material not involved in the battery reaction may cause a side reaction because the portion of the negative electrode that is not in contact with the positive electrode is large. Although control of the area of a positive electrode and a negative electrode is not specifically limited, For example, in the case of slurry coating, it can carry out by controlling the coating width.

<Separator>
Examples of the separator used in the nonaqueous electrolyte secondary battery of the present invention include porous materials and nonwoven fabrics. The material of the separator is preferably a material that does not dissolve in the organic solvent constituting the electrolytic solution, specifically, a polyolefin polymer such as polyethylene or polypropylene, a polyester polymer such as polyethylene terephthalate, cellulose or modified cellulose, Inorganic materials such as glass can be mentioned.

The thickness of the separator is preferably 1 to 500 μm. If it is less than 1 μm, it tends to break due to insufficient mechanical strength of the separator and cause an internal short circuit. On the other hand, when it is thicker than 500 μm, the load characteristics of the battery tend to be reduced due to the increase in the internal resistance of the battery and the distance between the positive and negative electrodes. A more preferred thickness is 10 to 50 μm.
The area ratio between the separator and the negative electrode used in the nonaqueous electrolyte secondary battery of the present invention is not particularly limited, but preferably satisfies the following formula (3).

1 ≦ F / E ≦ 1.5 (3)
(However, E represents the area of the negative electrode, and F represents the area of the separator.)
When F / E is less than 1, the positive electrode and the negative electrode are in contact with each other. When F / E is greater than 1.5, the volume required for the exterior increases, and the energy density of the battery may decrease.
<Nonaqueous electrolyte solution>
The nonaqueous electrolyte solution used in the nonaqueous electrolyte secondary battery of the present invention is not particularly limited, but the polymer is impregnated with an electrolyte solution in which a solute is dissolved in a nonaqueous solvent, or an electrolyte solution in which a solute is dissolved in a nonaqueous solvent. It is possible to use a gel electrolyte or the like.

The non-aqueous solvent preferably contains a cyclic aprotic solvent and / or a chain aprotic solvent. Examples of the cyclic aprotic solvent include cyclic carbonates, cyclic esters, cyclic sulfones and cyclic ethers. Examples of the chain aprotic solvent include chain carbonates, chain carboxylic acid esters and chain ethers. In addition to these, a solvent generally used as a solvent for nonaqueous electrolyte solutions such as acetonitrile may be used. More specifically, dimethyl carbonate, methyl ethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethylene carbonate, fluoroethylene carbonate, propylene carbonate, butylene carbonate, tetrahydrofuran, γ-butyrolactone, 1,2-dimethoxyethane, Sulfolane, dioxolane, methyl propionate and the like can be used. These solvents may be used alone or as a mixture of two or more. However, in view of the ease of dissolving the solute described below and the high conductivity of lithium ions, a mixture of two or more of these solvents. Is preferably used. A gel electrolyte in which an electrolyte is impregnated in a polymer can also be used.

The solute is not particularly limited. For example, lithium salts such as LiClO ₄ , LiBF ₄ , LiPF ₆ , LiAsF ₆ , LiCF ₃ SO ₃ , LiBOB (Lithium Bis (Oxalato) Borate), LiN (SO ₂ CF ₃ ) ₂ , Sodium salts such as NaClO ₄ , NaBF ₄ and NaPF ₆ and magnesium salts such as Mg [AlCl ₂ (C ₄ H ₉ ) (C ₂ H ₅ )] ₂ , C ₆ H ₅ MgCl and C ₆ H ₅ MgBr are used as solvents. It is preferable because it is easily dissolved. The concentration of the solute contained in the electrolytic solution is preferably 0.5 mol / L or more and 2.0 mol / L or less. If it is less than 0.5 mol / L, the desired ionic conductivity may not be exhibited. On the other hand, if it is higher than 2.0 mol / L, the solute may not be dissolved any more, and the viscosity increases and the load characteristic decreases. To do. The non-aqueous electrolyte solution may contain a trace amount of a flame retardant, a stabilizer and the like.

The amount of the nonaqueous electrolyte solution is not particularly limited, but is preferably 0.1 mL or more per 1 Ah of battery capacity. If it is less than 0.1 mL, the conduction of lithium ions accompanying the electrode reaction may not catch up, and the desired battery performance may not be exhibited. The nonaqueous electrolyte solution may be added to the positive electrode, the negative electrode, and the separator in advance, or may be added after winding or laminating a separator disposed between the positive electrode side and the negative electrode side.

As described above, the non-aqueous electrolyte is not limited to the non-aqueous electrolyte solution as long as contact between the positive electrode and the negative electrode can be prevented. A gel-like non-aqueous electrolyte may be used. In the case of using a gel-like material, the electrolyte may be impregnated in the positive electrode and the negative electrode, or may be in a state only between the positive electrode and the negative electrode.
<Other structures>
The positive electrode and the negative electrode of the nonaqueous electrolyte secondary battery of the present invention may have a form in which the same electrode is formed on both surfaces of a plate-like current collector, depending on the connection configuration of the battery. The positive electrode and the negative electrode formed on one surface, that is, a bipolar electrode may be used. In the case of the bipolar type, a conductive material and / or an insulating material is disposed between the positive electrode and the negative electrode in order to prevent a liquid junction between the positive electrode and the negative electrode through the current collector. In the case of a bipolar electrode, a separator is disposed between the positive electrode side and the negative electrode side of the adjacent bipolar electrode, and the positive electrode and An insulating sealing material is disposed around the negative electrode.

The non-aqueous electrolyte secondary battery of the present invention may be wound with a laminated film after being laminated or laminated, or a metal having a square shape, an elliptical shape, a cylindrical shape, a coin shape, a button shape, or a sheet shape. It may be packaged with a can. The exterior may be provided with a mechanism for releasing the generated gas or the like. Moreover, the mechanism which inject | pours the capture body 9 for recovering the function of the said non-aqueous electrolyte secondary battery which deteriorated may be provided. The number of stacked layers can be stacked until a desired battery capacity is exhibited.

The non-aqueous electrolyte secondary battery of the present invention can be an assembled battery by connecting a plurality of the non-aqueous electrolyte secondary batteries. The assembled battery of the present invention can be produced by appropriately connecting in series or in parallel according to a desired size, capacity, and voltage. Moreover, it is preferable that a control circuit is attached to the assembled battery in order to confirm the state of charge of each battery and improve safety.

<Example 1>
A Li ₄ Ti ₅ O ₁₂ / Li _1.1 Al _0.1 Mn _1.8 O ₄ battery was produced as follows.
(Preparation of negative electrode)
The negative electrode active material Li ₄ Ti ₅ O ₁₂ can be found in the literature ("Zero-Strain Insertion Material of Li [Li1 / 3Ti5 / 3] O4 for Rechargeable Lithium Cells" J. Electrochem. Soc., Volume 142, Issue 5, pp. 1431-1435 (1995)).

That is, first, titanium dioxide and lithium hydroxide are mixed so that the molar ratio of titanium and lithium is 5: 4, and then this mixture is heated at 800 ° C. for 12 hours in a nitrogen atmosphere to obtain a negative electrode active material. Produced.
100 parts by weight of this negative electrode active material, 3.2 parts by weight of a conductive additive (acetylene black), and PVdF binder (KF7305, manufactured by Kureha Chemical Co., Ltd.) (solid content concentration 5 wt%, NMP solution) are obtained with a solid content of 3.2. A slurry was prepared by mixing parts by weight. The slurry was applied to aluminum expanded metal (LW × SW = 8 × 4), and then vacuum dried at 150 ° C. to prepare a negative electrode. The LW represents “long way of mesh”, and SW represents “short way of mesh”.

(Preparation of positive electrode)
The Li _1.1 Al _0.1 Mn _1.8 O ₄ of the positive electrode active material, the literature ( "Lithium Aluminum Manganese Oxide Having Spinel -Framework Structure for Long-Life Lithium-Ion Batteries" Electrochemical and Solid-State Letters Volume9, Issue12, Pages A557 (2006) ).

That is, an aqueous dispersion of manganese dioxide, lithium carbonate, aluminum hydroxide, and boric acid was prepared, and a mixed powder was prepared by a spray drying method. At this time, the amounts of manganese dioxide, lithium carbonate and aluminum hydroxide were adjusted so that the molar ratio of lithium, aluminum and manganese was 1.1: 0.1: 1.8. Next, the mixed powder was heated at 900 ° C. for 12 hours in an air atmosphere, and then again heated at 650 ° C. for 24 hours. Finally, the powder was washed with water at 95 ° C. and dried to prepare a positive electrode active material.

100 parts by weight of this positive electrode active material, 3.2 parts by weight of conductive additive (acetylene black), and polyvinylidene fluoride (PVdF) binder (KF7305, manufactured by Kureha Chemical Co., Ltd.) (solid content concentration 5 wt%, NMP solution) A slurry was prepared by mixing 3.2 parts by weight of a solid content. The slurry was applied to aluminum expanded metal (LW × SW = 8 × 4), and then vacuum dried at 150 ° C. to produce a positive electrode.

(Capacitance measurement of negative electrode and positive electrode)
The produced negative electrode or positive electrode was used as a working electrode. As a counter electrode, a lithium metal plate was punched in the same area as the working electrode. The working electrode / separator (Celgard # 2500, manufactured by Celgard) / the counter electrode were laminated in this order in a laminate cell, and 1 mol / L of LiPF4 was dissolved in a nonaqueous solvent of ethylene carbonate / dimethyl carbonate = 3/7 vol%. A half cell was prepared by adding 0.5 mL of the product. The half-cell was allowed to stand at 25 ° C. for one day, and then connected to a charge / discharge test apparatus (HJ1005SD8; manufactured by Hokuto Denko). This half-cell was subjected to constant current discharge at 25 ° C. and 1 mA five times, and the fifth result was defined as the capacity of the negative electrode or the positive electrode.

(Manufacture of non-aqueous electrolyte secondary batteries)
First, the obtained positive electrode / separator / obtained negative electrode were laminated in this order. For the separator, two cellulose nonwoven fabrics (25 μm, 55 cm 2) were used. As a capturing body between two cellulose nonwoven fabrics, a stainless steel frame (frame width 5 mm, thickness 0.3 mm) of the same type as the outer edge of the separator was placed. The shape of the lithium metal is such that thin lithium metal plates having a width of 1 mm are arranged in a vertical lattice pattern at a pitch of 5 mm in a stainless steel frame. Next, after aluminum tabs were vibration welded to the positive and negative electrodes at both ends of the battery, they were placed in a bag-like aluminum laminate sheet. After injecting 4 mL of a non-aqueous electrolyte (ethylene carbonate / dimethyl carbonate = 3/7 vol%, LiPF ₆ 1 mol / L) in a dry atmosphere, a non-aqueous electrolyte secondary battery was fabricated by sealing while reducing the pressure. The non-aqueous electrolyte secondary battery produced in this way is referred to as a “cell” (the same applies to the following examples and comparative examples).

<Example 2>
As in Example 1, except that instead of the stainless steel frame in Example 1, lithium metal and polyvinylidene fluoride (PVdF) were mixed and then formed into the same shape as the stainless steel frame, the same as in Example 1 was used. A water electrolyte secondary battery (Li ₄ Ti ₅ O ₁₂ / Li _1.1 Al _0.1 Mn _1.8 O ₄ battery) was produced.

<Example 3>
In Example 1, a magnesium metal frame was used instead of the stainless steel frame, and the non-aqueous electrolyte secondary battery (Li ₄ Ti ₅ O ₁₂ / Li _1.1 Al _0.1 Mn _1.8 O ₄ battery) was produced.
<Example 4>
A nonaqueous electrolyte secondary battery (TiO ₂ (B) / Li _1.1 Al _0.1 Mn _1.8 O ₄ battery) was prepared in the same manner as in Example 1 except that TiO ₂ (B) was used as the negative electrode active material in Example 1. did. The negative electrode material TiO ₂ (B) was prepared by the method described in the literature (Materials Research Bulletin, Vol. 15, pp. 1129-1133 (1980)).

<Example 5>
In Example 1, NaNi _0.5 Mn _0.5 O ₂ was used as the positive electrode active material, and sodium metal and sodium ion-containing electrolyte (PC, NaPF6, 1.0 mol / L) were used as the metal to be crimped to the stainless steel frame. As in Example 1, a nonaqueous electrolyte secondary battery (Li ₄ Ti ₅ O ₁₂ / NaNi _0.5 Mn _0.5 O ₂ battery) was produced. The positive electrode material NaNi _0.5 Mn _0.5 O ₂ was produced by the method described in the literature (ECS Transactions, volume 16, issue 42, pp. 43-55 (2009)).

<Example 6>
In the positive electrode and negative electrode obtained in Example 1, a mixture of a solid electrolyte of polyethylene oxide (PEO) and an electrolyte solution composed of a propylene carbonate solution of LiPF6 was immersed and cured by hot pressing to obtain a positive electrode plate and a negative electrode plate. Lithium metal fine particles (diameter: 900 nm) were dispersed as a capturing body in the mixture of the electrolytic solution, and an electrolyte layer was formed by thermosetting. An electrode group is formed by laminating these in the order of positive electrode plate / electrolyte layer / negative electrode plate, and this electrode group is sealed in an aluminum laminate sheet in the same manner as in Example 1 to thereby form a nonaqueous electrolyte secondary battery (Li ₄ Ti ₅ O ₁₂ / capture dispersion PEO / Li _1.1 Al _0.1 Mn _1.8 O ₄ battery).

<Comparative Example 1>
A non-aqueous electrolyte secondary battery (Li ₄ Ti ₅ O ₁₂ / Li _1.1 Al _0.1 Mn _1.8 ) was used in the same manner as in Example 1 except that the capturing body (lithium metal pressure-bonded to the stainless steel frame) was not inserted in Example 1. O ₄ battery) was produced.
<Comparative example 2>
A non-aqueous electrolyte secondary battery (TiO ₂ (B) / Li _1.1 Al _0.1 Mn _1.8 O) is used in the same manner as in Example 4 except that the trapping body (lithium metal pressed onto the stainless steel frame) is not inserted in Example 4. ₄ batteries) were produced.

<Comparative Example 3>
A non-aqueous electrolyte secondary battery (Li ₄ Ti ₅ O ₁₂ / NaNi _0.5 Mn _0.5 O ₂ ) was used in the same manner as in Example 5 except that the trapping body (lithium metal pressed onto the stainless steel frame) was not inserted in Example 5. Battery).
<Comparative Example 4>
A nonaqueous electrolyte secondary battery (Li ₄ Ti ₅ O ₁₂ / PEO / Li _1.1 Al _0.1 Mn _1.8 O ₄ battery) was obtained in the same manner as in Example 6 except that the lithium metal fine particles were not dispersed in Example 6.

(Charge / discharge cycle test)
As schematically shown in FIG. 5, a constant current drive source 21, a voltage detection unit 23 that detects a cell terminal voltage V, and a charge / discharge control unit 24 that drives the relay switch 22 are provided. According to the detected terminal voltage V, the charge / discharge control unit 24 drives the relay switch 22 to switch the direction of the constant current I flowing through the cell. That is, when the terminal voltage V is lower than the upper limit voltage V1, a current flows in the direction of charging the cell, and when the terminal voltage V exceeds the lower limit voltage V2, the direction of the current is switched and discharged. However, V2> V1. The constant current I was set to a current value at which discharge was completed in just one hour by discharging the cell having the capacity measured in the above <Measurement of negative electrode and positive electrode capacities> (referred to as “1 hour Rate current value)). In this way, charge / discharge was repeated a predetermined number of times to measure how much the battery capacity had decreased. “Battery capacity” refers to a value “TI” obtained by multiplying current I by time T from the start of discharge of the battery to the end of discharge. At the beginning of the cycle, the internal resistance of the cell is small and the battery capacity (TI value) is large, but when the cycle is repeated, the battery capacity decreases and the discharge ends in a short time. Since the value of the current I is constant, the battery capacity may be considered to be proportional to the discharge time T.

For Examples 1 to 4, Example 6, Comparative Examples 1 to 2, and Comparative Example 4, the battery capacity retention rate after repeating charge / discharge 250 times using a charge / discharge test apparatus (HJ1005SD8; manufactured by Hokuto Denko Co., Ltd.) Each measurement is shown in Table 1. Moreover, about Example 5 and the comparative example 3, since the battery capacity maintenance factor after repeating charging / discharging 100 times was measured, it shows in Table 1. Here, the “battery capacity maintenance rate” is a numerical value (unit%) obtained by dividing “battery capacity after repeated charging / discharging a predetermined number of times” by “battery capacity in the first cycle of charging / discharging cycle test”. Further, in addition to the measurement of the battery capacity retention rate, the cell was immersed in ethylene carbonate before and after the measurement, and the increased volume difference was measured, and this was taken as the gas generation amount. The measurement results of the gas generation amount are listed together in Table 1 (unit: mL).

The nonaqueous electrolyte secondary battery (Li ₄ Ti ₅ O ₁₂ / Li _1.1 Al _0.1 Mn _1.8 O ₄ battery) of Comparative Example 1 has a current value of 60 ° C., upper limit voltage 3.4 V, lower limit voltage 0 V, and 1 hour rate. A 250 cycle test was conducted. The battery capacity gradually decreased with each cycle, and the capacity retention rate at 250 cycles was 89% of the initial stage. The amount of gas generated depending on the charge / discharge cycle was 8.76 mL.
In addition, the nonaqueous electrolyte secondary battery (Li ₄ Ti ₅ O ₁₂ / Li _1.1 Al _0.1 Mn _1.8 O ₄ battery, capture body = lithium metal) of Example 1 and Example 2 is also 60 ° C. and the upper limit voltage is 3.4 V. A 250 cycle test was conducted at a lower limit voltage of 0 V and a current value of 1 hour rate. The battery capacity gradually decreased with each cycle, and the capacity retention rates at 250 cycles were 94% and 92% of the initial values, respectively. The amounts of gas generated depending on the charge / discharge cycle were 4.30 mL and 5.44 mL, respectively.

FIG. 6 shows a graph in which the battery capacity retention rates of Example 1 and Comparative Example 1 are plotted against the number of charge / discharge cycles. As the number of charge / discharge cycles increases, the battery capacity retention rate decreases, but it can be seen that Example 1 has a lower decrease rate of the battery capacity retention rate than Comparative Example 1. From this, it can be seen that the charge / discharge cycle characteristics are improved by disposing an alkali metal trap in the cell. Moreover, it turns out that the gas generation | occurrence | production depending on a charging / discharging cycle is suppressed from the result shown in Table 1.

The non-aqueous electrolyte secondary battery of Example 3 (Li ₄ Ti ₅ O ₁₂ / Li _1.1 Al _0.1 Mn _1.8 O ₄ battery, magnesium metal frame) is also 60 ° C., upper limit voltage 3.4 V, lower limit voltage 0 V, 1 hour rate A 250 cycle test was conducted at a current value of. The capacity gradually decreased with each cycle, and the capacity retention rate at 250 cycles was 91% of the initial stage. The amount of gas generated due to the charge / discharge cycle was 6.22 mL. From this, it can be seen that by arranging the alkaline earth metal in the cell, the charge / discharge cycle characteristics are improved and gas generation is suppressed.

The nonaqueous electrolyte secondary battery (TiO ₂ (B) / Li _1.1 Al _0.1 Mn _1.8 O4 battery) of Comparative Example 2 is 250 cycles at 60 ° C., upper limit voltage 3.4 V, lower limit voltage 0 V, and current value of 1 hour rate. A test was conducted. The capacity decreased with each cycle, and the capacity retention rate at 250 cycles was 66% of the initial stage. Moreover, the gas generation amount resulting from a charging / discharging cycle was 10.78 mL.
In addition, the nonaqueous electrolyte secondary battery of Example 4 (TiO ₂ (B) / Li _1.1 Al _0.1 Mn _1.8 O ₄ battery, capture body = lithium metal) is 60 ° C., upper limit voltage 3.4 V, lower limit voltage 0 V, A 250 cycle test was conducted at a current value of 1 hour rate. The capacity decreased with each cycle, and the capacity retention rate at 250 cycles was 75% of the initial value. Moreover, the gas generation amount resulting from a charging / discharging cycle was 5.60 mL. From this, it can be seen that by arranging the alkali metal in the cell, the charge / discharge cycle characteristics are improved and gas generation is suppressed.

The nonaqueous electrolyte secondary battery (Li ₄ Ti ₅ O ₁₂ / NaNi _0.5 Mn _0.5 O ₂ battery) of Comparative Example 3 is 100 cycles at 25 ° C., upper limit voltage 3.4 V, lower limit voltage 0 V, and current value of 1 hour rate. A test was conducted. The capacity retention rate at 100 cycles was 61% of the initial value. Moreover, the gas generation amount resulting from a charging / discharging cycle was 17.78 mL.
The nonaqueous electrolyte secondary battery of Example 5 (Li ₄ Ti ₅ O ₁₂ / NaNi _0.5 Mn _0.5 O ₂ battery, capture body = sodium metal) was also 25 ° C., upper limit voltage 3.4 V, lower limit voltage 0 V, 1 hour rate A 100 cycle test was conducted at a current value of. The capacity maintenance rate at 100 cycles was 71% of the initial stage, and the amount of gas generated due to the charge / discharge cycle was 10.32 mL. Therefore, by placing an alkali metal in the cell, the charge / discharge cycle characteristics were improved. And it turns out that gas generation is suppressed.

For non-aqueous electrolyte secondary battery of Comparative Example _{_{_{4 (Li 4 Ti 5 O 12}}} / PEO / Li 1.1 Al 0.1 Mn 1.8 O 4 batteries), 60 ° C., the upper limit voltage 3.4 V, lower limit voltage 0V, 1 hour-rate current A 250 cycle test was performed on the values. The capacity retention rate at 250 cycles was 85% in the initial stage. Moreover, the gas generation amount resulting from a charging / discharging cycle was 4.12 mL.
Also for the nonaqueous electrolyte secondary battery of Example 6 (Li ₄ Ti ₅ O ₁₂ / captured dispersion PEO / Li _1.1 Al _0.1 Mn _1.8 O ₄ battery), 60 ° C., upper limit voltage 3.4 V, lower limit voltage 0 V, 1 A 250 cycle test was conducted at the current value of the time rate. The capacity retention rate at 250 cycles was 89% of the initial stage, and the amount of gas generated due to the charge / discharge cycle was 2.26 mL. Therefore, the charge / discharge cycle characteristics were improved by dispersing the trap in the solid electrolyte. It can be seen that the generation of gas due to the charge / discharge cycle is suppressed.

DESCRIPTION OF SYMBOLS 1 Nonaqueous electrolyte secondary battery 2 Current collector for positive electrodes 4 Current collector for negative electrodes 3 Nonaqueous electrolyte layer 5 Positive electrode active material 6 Negative electrode

active materials

7, 7a, 7b Separator 8 Insulating sealing material 9 Capturing body 10 Frame

Claims

A positive electrode, a negative electrode, and a non-aqueous electrolyte layer interposed between the positive electrode and the negative electrode;
A metal, intermetallic compound, or alloy having a redox potential not higher than the negative electrode operating potential in a state where it is in contact with the non-aqueous electrolyte and is not in contact with either the positive electrode or the negative electrode between the positive electrode and the negative electrode A non-aqueous electrolyte secondary battery in which a capturing body including
The non-aqueous electrolyte secondary battery according to claim 1, wherein the metal contained in the trap is an alkali metal, an alkali intermetallic compound, or an alloy.
The non-aqueous electrolyte secondary battery according to claim 2, wherein the alkali metal is lithium or sodium.
The non-aqueous electrolyte secondary battery according to claim 1, wherein the metal contained in the capturing body is an alkaline earth metal, an alkaline earth intermetallic compound, or an alloy.
The nonaqueous electrolyte secondary battery according to any one of claims 1 to 4, wherein the trapping body is dispersedly arranged in the nonaqueous electrolyte solution.
The nonaqueous electrolyte according to any one of claims 1 to 4, wherein a porous film serving as a separator is interposed between the positive electrode and the negative electrode, and the capturing body is present in the porous film. Secondary battery.
The non-aqueous electrolyte secondary battery according to any one of claims 1 to 4, wherein the trapping body is disposed in a gel-like non-aqueous electrolyte.
The nonaqueous electrolyte secondary battery according to any one of claims 1 to 4, wherein a negative electrode active material that operates at -2.7 V or higher and -1.0 V or lower with respect to a standard hydrogen electrode is used as the negative electrode. .
The nonaqueous electrolyte secondary battery according to any one of claims 1 to 4, wherein lithium titanium oxide or titanium oxide is used as a negative electrode active material constituting the negative electrode.
5. The positive electrode active material constituting the positive electrode, wherein lithium manganese oxide or a material obtained by substituting a part of manganese of lithium manganese oxide with a different metal or a different material is used. The non-aqueous electrolyte secondary battery described in 1.