JP6601951B2 - Non-aqueous secondary battery - Google Patents

Description

  The present invention relates to a non-aqueous secondary battery having a negative electrode containing a material containing Si and O as constituent elements and having good charge / discharge cycle characteristics.

  Non-aqueous secondary batteries, such as lithium ion secondary batteries, have high voltage and high capacity, so there are great expectations for their development.

  By the way, recently, there has been a demand for a further increase in capacity of a non-aqueous secondary battery for portable devices that has been downsized and multifunctional, and in response to this, a negative electrode active material has been used as a widely used graphite. In addition, it is also considered to change to a material that can accommodate more Li, such as low crystalline carbon, Si (silicon), Sn (tin), etc. (hereinafter also referred to as “high capacity negative electrode material”). Yes.

As one of such high-capacity negative electrode materials for non-aqueous secondary batteries, SiO _x having a structure in which Si ultrafine particles are dispersed in SiO ₂ has attracted attention. However, a high capacity negative electrode material such as SiO _x has a very large volume change amount due to charging / discharging. Therefore, in a battery using this, there is a risk that the battery characteristics may be rapidly deteriorated by repeated charging / discharging.

For example, in order to increase the capacity of the non-aqueous secondary battery, it is advantageous to increase the proportion of SiO _{x in} the negative electrode mixture layer, but when the proportion of SiO _{x in} the negative electrode mixture layer is increased, There is a tendency that a problem due to volume change of SiO _x accompanying charge / discharge of a non-aqueous secondary battery becomes more obvious.

For these reasons, in non-aqueous secondary batteries using SiO _x as a negative electrode material, a technique for solving the problem caused by the volume change of the negative electrode accompanying charge / discharge has been studied. For example, in Patent Document 1, as a binder for a negative electrode, polyimide or polyamideimide capable of strongly bonding SiO _x and a conductive auxiliary agent than styrene butadiene rubber (SBR) and carboxymethyl cellulose (CMC), which are conventionally used widely, By using polyamide, it is possible to prevent the SiO _x particles and the conductive auxiliary agent from separating due to charging / discharging of the battery and to reduce the conductivity in the negative electrode mixture layer, and to deform the negative electrode accompanying charging / discharging of the battery. A non-aqueous secondary battery in which deterioration of battery characteristics is suppressed by providing a porous layer for suppression on the surface of the negative electrode mixture layer has been proposed. According to the technique described in Patent Document 1, even if the ratio of SiO _x in the negative electrode mixture layer is high, it is possible to satisfactorily suppress a decrease in battery characteristics associated with charge / discharge of the battery.

International Publication No. 2009/063902

  The present invention has a negative electrode containing a material containing Si and O as constituent elements, and a non-aqueous secondary battery having good charge / discharge cycle characteristics by a technique different from the technique described in Patent Document 1. The purpose is to provide.

  The non-aqueous secondary battery of the present invention that has achieved the above object is a negative electrode mixture containing a positive electrode having a positive electrode mixture layer containing a positive electrode active material on one or both sides of a current collector, a negative electrode active material, and a binder. A negative electrode having a layer on one or both sides of a current collector, a separator, and a non-aqueous electrolyte, and the positive electrode mixture layer contains a lithium-containing composite oxide containing lithium and a transition metal as a positive electrode active material. The negative electrode mixture layer is a composite of a material containing Si and O as constituent elements (however, the atomic ratio x of O to Si is 0.5 ≦ x ≦ 1.5) and a carbon material. As a negative electrode active material, and at least one imide-based binder selected from the group consisting of polyamideimide and polyimide, polyvinylidene fluoride, and polyvinylpyrrolidone as a binder, When the contents of inda, the polyvinylidene fluoride, and the polyvinylpyrrolidone in the negative electrode mixture layer are A (mass%), B (mass%), and C (mass%), respectively, 1 ≦ {A / ( B + C)} ≦ 5 is satisfied.

  ADVANTAGE OF THE INVENTION According to this invention, it has a negative electrode containing the material which contains Si and O in a structural element, and can provide a non-aqueous secondary battery with favorable charging / discharging cycling characteristics.

It is a top view which represents typically an example of the positive electrode which concerns on the nonaqueous secondary battery of this invention. It is a top view which represents typically an example of the negative electrode which concerns on the nonaqueous secondary battery of this invention. It is a top view which represents typically an example of the non-aqueous secondary battery of this invention. It is the II sectional view taken on the line of FIG.

The negative electrode according to the nonaqueous secondary battery of the present invention has a structure in which a negative electrode mixture layer containing a negative electrode active material and a binder is formed on one side or both sides of a negative electrode current collector. A composite of SiO _x and a carbon material is used as the negative electrode active material.

The SiO _x may contain Si microcrystal or amorphous phase. In this case, the atomic ratio of Si and O is a ratio including Si microcrystal or amorphous phase Si. That is, SiO _x includes a structure in which Si (for example, microcrystalline Si) is dispersed in an amorphous SiO ₂ matrix, and this amorphous SiO ₂ is dispersed in the SiO ₂ matrix. It is sufficient that the atomic ratio x satisfies 0.5 ≦ x ≦ 1.5 in combination with Si. For example, in the case of a material in which Si is dispersed in an amorphous SiO ₂ matrix and the material has a molar ratio of SiO ₂ to Si of 1: 1, x = 1, so that the structural formula is represented by SiO. The In the case of a material having such a structure, for example, in X-ray diffraction analysis, a peak due to the presence of Si (microcrystalline Si) may not be observed, but when observed with a transmission electron microscope, the presence of fine Si Can be confirmed.

Then, SiO _x is a complex complexed with carbon materials, for example, it is preferable that the surface of the SiO _x is coated with a carbon material. Since SiO _x has poor conductivity, when it is used as a negative electrode active material, from the viewpoint of securing good battery characteristics, a conductive material (conductive aid) is used, and SiO _x and conductive material in the negative electrode are used. Therefore, it is necessary to form a good conductive network by mixing and dispersing with each other. If complexes complexed with carbon material SiO _x, for example, simply than with a material obtained by mixing a conductive material such as SiO _x and the carbon material, good conductive network in the negative electrode Formed.

The complex of the SiO _x and the carbon material, as described above, other although the surface of the SiO _x coated with carbon material, such as granules of SiO _x and the carbon material can be cited.

In addition, since the composite in which the surface of SiO _x is coated with a carbon material is further combined with a conductive material (carbon material or the like), a better conductive network can be formed in the negative electrode. Thus, it is possible to realize a non-aqueous secondary battery with higher capacity and better battery characteristics (for example, charge / discharge cycle characteristics). The complex of the SiO _x and the carbon material coated with a carbon material, for example, like granules the mixture was further granulated with SiO _x and the carbon material coated with a carbon material.

Further, as SiO _x whose surface is coated with a carbon material, the surface of a composite (for example, a granulated body) of SiO _x and a carbon material having a smaller specific resistance value is further coated with a carbon material. Those can also be preferably used. In the non-aqueous secondary battery having a negative electrode containing SiO _x as a negative electrode active material, it is possible to form a better conductive network when SiO _x and the carbon material are dispersed inside the granule. Battery characteristics such as load discharge characteristics can be further improved.

Preferred examples of the carbon material that can be used to form a composite with SiO _x include carbon materials such as low crystalline carbon, carbon nanotubes, and vapor grown carbon fibers.

The details of the carbon material include at least one selected from the group consisting of fibrous or coiled carbon materials, carbon black (including acetylene black and ketjen black), artificial graphite, graphitizable carbon, and non-graphitizable carbon. A seed material is preferred. A fibrous or coiled carbon material is preferable in that it easily forms a conductive network and has a large surface area. Carbon black (including acetylene black and ketjen black), graphitizable carbon, and non-graphitizable carbon have high electrical conductivity and high liquid retention, and even if SiO _x particles expand and contract. This is preferable in that it has a property of easily maintaining contact with the particles.

Moreover, graphite can also be used as a carbon material related to a composite of SiO _x and a carbon material. Graphite, like carbon black, has high electrical conductivity and high liquid retention. Furthermore, even if SiO _x particles expand and contract, they have the property of easily maintaining contact with the particles. Therefore, it can be preferably used for forming a complex with SiO _x .

Among the carbon materials exemplified above, a fibrous carbon material is particularly preferable for use when the composite with SiO _x is a granulated body. Fibrous carbon material can follow the expansion and contraction of SiO _x with the charging and discharging of the battery due to the high shape is thin threadlike flexibility, also because bulk density is large, many and SiO _x particles It is because it can have a junction. Examples of the fibrous carbon include polyacrylonitrile (PAN) -based carbon fiber, pitch-based carbon fiber, vapor-grown carbon fiber, and carbon nanotube, and any of these may be used.

The fibrous carbon material can also be formed on the surface of the SiO _x particles by, for example, a vapor phase method.

The composite of SiO _x and the carbon material may further have a material layer (a material layer containing non-graphitizable carbon) that covers the carbon material coating layer on the particle surface.

In complex with SiO _x and the carbon material, the ratio between the SiO _x and the carbon material, from the viewpoint of satisfactorily exhibiting action by complexation with carbon materials, SiO x: relative to ₁₀₀ parts by mass, a carbon material The amount is preferably 5 parts by mass or more, and more preferably 10 parts by mass or more. Further, in the composite, if the ratio of the carbon material to be combined with SiO _x is too large, it may lead to a decrease in the amount of SiO _x in the negative electrode mixture layer, and the effect of increasing the capacity may be reduced. SiO _x: relative to 100 parts by weight, the carbon material, and more preferably preferably not more than 50 parts by weight, more than 40 parts by weight.

The composite of the SiO _x and the carbon material can be obtained, for example, by the following method.

First, a manufacturing method in the case of combining SiO _x will be described. A dispersion liquid in which SiO _x is dispersed in a dispersion medium is prepared, and sprayed and dried to produce composite particles including a plurality of particles. For example, ethanol or the like can be used as the dispersion medium. It is appropriate to spray the dispersion in an atmosphere of 50 to 300 ° C. In addition to the above method, similar composite particles can be produced also by a granulation method by a mechanical method using a vibration type or planetary type ball mill or rod mill.

Incidentally, the SiO _x, in the case of manufacturing a granulated body with small carbon material resistivity value than SiO _x is adding the carbon material in the dispersion liquid of SiO _x are dispersed in a dispersion medium, the dispersion by using a liquid, by a similar method to the case of composite of SiO _x may be a composite particle (granule). Further, by granulation process according to the similar mechanical method, it is possible to produce a granular material of the SiO _x and the carbon material.

Next, when the surface of SiO _x particles (SiO _x composite particles or a granulated body of SiO _x and a carbon material) is coated with a carbon material to form a composite, for example, the SiO _x particles and the hydrocarbon-based material The gas is heated in the gas phase, and carbon generated by pyrolysis of the hydrocarbon-based gas is deposited on the surface of the particles. As described above, according to the vapor deposition (CVD) method, the hydrocarbon-based gas spreads to every corner of the composite particle, and the surface of the particle and the pores in the surface are thin and contain a conductive carbon material. Since a uniform film (carbon material coating layer) can be formed, the SiO _x particles can be imparted with good conductivity with a small amount of carbon material.

In the production of SiO _x coated with a carbon material, the processing temperature (atmosphere temperature) of the vapor deposition (CVD) method varies depending on the type of hydrocarbon gas, but usually 600 to 1200 ° C. is appropriate. Among these, the temperature is preferably 700 ° C. or higher, and more preferably 800 ° C. or higher. This is because the higher the treatment temperature, the less the remaining impurities, and the formation of a coating layer containing carbon having high conductivity.

  As the liquid source of the hydrocarbon-based gas, toluene, benzene, xylene, mesitylene and the like can be used, but toluene that is easy to handle is particularly preferable. By vaporizing them (for example, bubbling with nitrogen gas), a hydrocarbon-based gas can be obtained. Moreover, methane gas, acetylene gas, etc. can also be used.

In addition, after the surface of SiO _x particles (SiO _x composite particles or a granulated body of SiO _x and a carbon material) is covered with a carbon material by a vapor deposition (CVD) method, a petroleum-based pitch or a coal-based pitch is used. At least one organic compound selected from the group consisting of a thermosetting resin and a condensate of naphthalene sulfonate and aldehydes is attached to a coating layer containing a carbon material, and then the organic compound is attached. The obtained particles may be fired.

Specifically, a dispersion liquid in which a SiO _x particle (SiO _x composite particle or a granulated body of SiO _x and a carbon material) coated with a carbon material and the organic compound are dispersed in a dispersion medium is prepared, The dispersion is sprayed and dried to form particles coated with the organic compound, and the particles coated with the organic compound are fired.

  An isotropic pitch can be used as the pitch, and a phenol resin, a furan resin, a furfural resin, or the like can be used as the thermosetting resin. As the condensate of naphthalene sulfonate and aldehydes, naphthalene sulfonic acid formaldehyde condensate can be used.

As a dispersion medium for dispersing the SiO _x particles coated with the carbon material and the organic compound, for example, water or alcohols (ethanol or the like) can be used. It is appropriate to spray the dispersion in an atmosphere of 50 to 300 ° C. The firing temperature is usually 600 to 1200 ° C., preferably 700 ° C. or higher, and more preferably 800 ° C. or higher. This is because the higher the processing temperature, the less the remaining impurities, and the formation of a coating layer containing a high-quality carbon material with high conductivity. However, the processing temperature needs to be lower than the melting point of SiO _x .

The negative electrode active material, may be used only complexes of SiO _x and the carbon material may be used other anode active material with the complex of the SiO _x and the carbon material. Other negative electrode active materials used together with the composite of SiO _x and carbon material include various materials conventionally known as negative electrode active materials for non-aqueous secondary batteries, but have a relatively large capacity. In addition, since the volume change due to charging / discharging of the battery is smaller than that of SiO _x , graphite materials such as highly crystalline natural graphite and artificial graphite are preferable. When natural graphite is used, heat treatment may be performed at a higher temperature, artificial graphite fine particles (granular, flat, etc.) may be coated, or an organic substance such as a resin may be coated.

The content of the composite of SiO _x and the carbon material in the total amount of the negative electrode active material is preferably 40% by mass or more and more preferably 70% by mass or more from the viewpoint of increasing the capacity of the battery. preferable. Since only the composite of SiO _x and carbon material may be used for the negative electrode active material, the content of the composite of SiO _x and carbon material in the total amount of the negative electrode active material is 100% by mass. There may be. In addition, as described above, the charge / discharge cycle characteristics of the battery can be further enhanced by using a graphite material together. In this case, the inclusion of the composite of SiO _x and the carbon material in the total amount of the negative electrode active material The amount is preferably 95% by mass or less, and more preferably 85% by mass or less.

  The negative electrode active material content (total content of all negative electrode active materials) in the negative electrode mixture layer is preferably 70 to 95% by mass.

  The binder according to the negative electrode mixture layer includes at least one imide-based binder selected from the group consisting of polyamideimide (PAI) and polyimide (PI), polyvinylidene fluoride (PVDF), and polyvinylpyrrolidone (PVP). Is used.

  When the content of the imide binder, PVDF, and PVP in the negative electrode mixture layer is A (mass%), B (mass%), and C (mass%), respectively, 1 ≦ {A / (B + C)} The relationship of ≦ 5 is satisfied.

In a non-aqueous secondary battery using a composite of SiO _x and a carbon material for the negative electrode, when an imide binder such as PAI or PI is used as the binder of the negative electrode mixture layer, the composite or conductive auxiliary agent is used. Since it can be firmly bonded, it is possible to prevent the composites from separating from each other and the composite from the conductive assistant even _if the volume change of SiO _x occurs as the battery is charged / discharged. The charge / discharge cycle characteristics of the water secondary battery can be enhanced. However, when PVDF and PVP are used together with an imide-based binder, and the relationship between the contents of these binders satisfies the above formula, the charge / discharge cycle characteristics of the non-aqueous secondary battery are further improved. Is possible.

  In the negative electrode, when PVDF and PVP are used as a binder together with an imide-based binder, and the relationship between the contents of these binders satisfies the above formula, why is the charge / discharge cycle characteristic of the non-aqueous secondary battery? It is not certain whether it can be increased, but it is speculated that it may be due to the following reasons.

When an imide-based binder is used alone as the binder, the negative electrode mixture layer becomes hard, but it is considered that the following (1) and (2) are obtained by combining PVDF and PVP.
(1) The flexibility of the negative electrode mixture layer is improved.
(2) Since the uniformity of the charge / discharge characteristics in the negative electrode mixture layer is improved, variation in expansion (local expansion) depending on the location in the negative electrode mixture layer is reduced.
And it becomes possible by these (1) and (2) to relieve | moderate / suppress the damage by the expansion | swelling of a negative mix layer, and, thereby, it is thought that the charging / discharging cycling characteristics of a battery improve more.

  However, when the amount of PVDF and PVP in the negative electrode mixture layer is small, the effects of the above (1) and (2) are weak, and when these amounts in the negative electrode mixture layer are excessive, the strength of the negative electrode mixture layer is increased. It becomes weak. Therefore, it is necessary to combine an imide-based binder that contributes to improving the strength of the negative electrode mixture layer with PVDF and PVP that contribute to improving the flexibility of the negative electrode mixture layer and the uniformity of charge / discharge characteristics at an appropriate mass ratio. it is conceivable that.

  Moreover, when the relationship between the content of the imide-based binder, PVDF, and PVP in the negative electrode mixture layer satisfies the above formula, the balance between the strength and flexibility of the negative electrode mixture layer becomes good. Therefore, deformation of the negative electrode accompanying charging / discharging of the battery can be suppressed. Therefore, for example, as described above, the charge / discharge cycle characteristics can be further improved without forming the porous layer employed in the negative electrode related to the non-aqueous secondary battery described in Patent Document 1. A non-aqueous secondary battery has good productivity.

  Among the imide-based binders, various PAIs can be used as the PAI. For example, because of good electron mobility, the molecular chain can be used as shown in [1] to [3] below. Those having an aromatic ring are preferred.

[1] It has an aramid structural unit represented by the following formula (1) and an amideimide unit represented by the following formula (2), and the total of the aramid structural unit and the amideimide structural unit is 100 mol%. An aramid-amidoimide copolymer in which the aramid structural unit is 18 to 55 mol%.

In the formula (1), Ar ¹ is an m-phenylene group or a p-phenylene group. In the formula (2), Ar ² is a trivalent aromatic residue having one aromatic ring. Furthermore, R ¹ in the formula (1) and R ² in the formula (2) are structural units represented by the following formula (3) or structural units represented by the following formula (4), and R ¹ And R ² are summed, the molar ratio of the structural unit represented by the following formula (3) and the structural unit represented by the following formula (4) is 55:45 to 85:15.

[2] It has an aramid structural unit represented by the following formula (5) and an amideimide structural unit represented by the following formula (6), and the total of the aramid structural unit and the amideimide structural unit is 100 mol%. An aramid-amidoimide copolymer in which the aramid structural unit is 18 to 80 mol%.

In the formula (5), Ar ³ is an m-phenylene group or a p-phenylene group. In the formula (6), Ar ⁴ is a trivalent aromatic residue having one aromatic ring. Furthermore, R ³ in the formula (5) and R ⁴ in the formula (6) are structural units represented by the following formula (7) or structural units represented by the following formula (8), and R ³ And R ⁴ each contain 60 mol% or more of a structural unit represented by the following formula (7). Incidentally, when the sum of the ^{R 3} and ^{R 4,} the molar ratio of the structural unit represented by the following formula (7), the structural unit represented by the following formula (8) is 60: 40 to 80: is 20 It is preferable.

[3] When the structural unit represented by the following formula (9) and the structural unit represented by the following formula (10) are included, and the total of both the structural units is 100 mol%, the following (9 PAI whose structural unit represented by the formula is 60 to 80 mol%.

  In the PAI of [3], it is preferable that imidization is not completely completed and a part of the PAI stays in the state of polyamic acid represented by the following formula (11). In this case, the adhesiveness between each component in the electrode mixture layer or between the electrode mixture layer and the current collector is further improved. In this case, the portion remaining in the state of polyamic acid can be evaluated by, for example, the residual carboxyl group amount in PAI measured by the method described in JP-A-2007-246680, and the residual carboxyl group amount is 0 It is preferably 0.05 to 0.40 mmol.

In the formula (11), R ⁵ is a structural unit represented by the formula (3) or a structural unit represented by the formula (4).

  Of the imide binders, PI includes various known polyimides, and any of thermoplastic PI and thermosetting PI can be used. In the case of thermosetting PI, either a condensation type PI or an addition type PI may be used. More specifically, for example, “Semicofine (trade name)” manufactured by Toray Industries, “PIX series (trade name)” manufactured by Hitachi Chemical DuPont Microsystems, “HCI series (trade name)” manufactured by Hitachi Chemical, Ube Commercial products such as “U-Varnish (trade name)” manufactured by Kosan Co., Ltd. can be used. For the same reason as in the case of PAI, those having an aromatic ring in the molecular chain, that is, aromatic PI are more preferred.

  As the imide-based binder, one or more of PAI may be used, one or more of PI may be used, and one or more of PAI and PI may be used. One or more may be used together.

The content A of the imide-based binder in the negative electrode mixture layer is 0.5% by mass or more from the viewpoint of increasing the binding strength of the composite of SiO _x and the carbon material and the conductive aid used as necessary. It is preferable that it is 2% by mass or more. On the other hand, from the viewpoint of suppressing the total content of the binder in the negative electrode mixture layer by limiting the amount of the imide-based binder in the negative electrode mixture layer to some extent, increasing the negative electrode capacity and the conductivity in the negative electrode mixture layer, the negative electrode The content A of the imide binder in the mixture layer is preferably 25% by mass or less, and more preferably 10% by mass or less.

  In addition, the content B of PVDF in the negative electrode mixture layer is preferably 0.45% by mass or more from the viewpoint of satisfactorily exerting the effect of improving the flexibility of the negative electrode mixture layer by using PVDF. % Or more is more preferable. On the other hand, from the viewpoint of suppressing the total content of the binder in the negative electrode mixture layer by limiting the amount of PVDF in the negative electrode mixture layer to some extent, and increasing the capacity of the negative electrode and the conductivity in the negative electrode mixture layer, the negative electrode mixture The PVDF content B in the layer is preferably 4% by mass or less, and more preferably 3% by mass or less.

  Furthermore, the content C of PVP in the negative electrode mixture layer is preferably 0.05% by mass or more from the viewpoint of satisfactorily exerting the effect of improving the uniformity of the charge / discharge characteristics due to the use of PVP. More preferably, it is at least mass%. On the other hand, from the viewpoint of suppressing the total content of the binder in the negative electrode mixture layer by limiting the amount of PVP in the negative electrode mixture layer to some extent, and increasing the capacity of the negative electrode and the conductivity in the negative electrode mixture layer, the negative electrode mixture The PVP content C in the layer is preferably 1% by mass or less, and more preferably 0.5% by mass or less.

  In the negative electrode mixture layer, binders used in the negative electrode mixture layer related to the negative electrode of the conventional nonaqueous secondary battery, for example, styrene butadiene rubber (SBR), carboxymethyl cellulose (CMC), etc. are also imide binders, Can be used with PVDF and PVP.

  The binder content (total content) in the negative electrode mixture layer is preferably 1% by mass or more, more preferably 2% by mass or more, and preferably 35% by mass or less. It is more preferable that the amount is not more than mass%. Therefore, when a binder other than an imide binder, PVDF and PVP is also used for the binder of the negative electrode mixture layer, the content A of the imide binder in the negative electrode mixture layer, the content B of PVDF and the content of PVP It is preferable to use a binder other than the imide-based binder, PVDF, and PVP as long as the amount C satisfies each of the above preferred values and the total content of the binder satisfies the above preferred value.

  The negative electrode mixture layer may contain a conductive additive. As the conductive auxiliary agent contained in the negative electrode mixture layer, carbon materials such as carbon blacks such as acetylene black, ketjen black, channel black, furnace black, lamp black, and thermal black; carbon fiber; Conductive fibers such as metal fibers; carbon fluoride; metal powders such as aluminum; zinc oxide; conductive whiskers such as potassium titanate; conductive metal oxides such as titanium oxide; polyphenylene derivatives, etc. Or an organic conductive material can be used. As the conductive assistant, those exemplified above may be used singly or in combination of two or more.

When the conductive auxiliary agent is contained in the negative electrode mixture layer, the content of the conductive auxiliary agent in the negative electrode mixture layer is preferably 0.1% by mass or more, and more preferably 0.5% by mass or more. Moreover, it is preferable that it is 10 mass% or less, and it is more preferable that it is 5 mass% or less.

  The negative electrode is, for example, a paste obtained by dispersing a negative electrode mixture containing a negative electrode active material and a binder and, if necessary, a conductive additive in a solvent such as N-methyl-2-pyrrolidone (NMP) or water. Or a slurry-like negative electrode mixture-containing composition (the binder may be dissolved in a solvent), which is applied to one or both sides of the current collector, dried, and then calendered as necessary. It can manufacture through the process of performing press processing, such as a process. However, the negative electrode is not limited to those manufactured by the above method, and may be manufactured by other methods.

  As the current collector for the negative electrode, a foil made of copper or nickel, a punching metal, a net, an expanded metal, or the like can be used, but a copper foil is usually used. In the negative electrode current collector, when the thickness of the entire negative electrode is reduced in order to obtain a battery having a high energy density, the upper limit of the thickness is preferably 30 μm, and the lower limit is 4 μm in order to ensure mechanical strength. Is desirable.

In the nonaqueous secondary battery of the present invention, the irreversible capacity of SiO _x used in the negative electrode is large, and a relatively large amount of Li ions released from the positive electrode (positive electrode active material) by the initial charge of the battery. Since it cannot return to the positive electrode in the next discharge, there is a possibility that the capacity that the positive electrode originally has cannot be sufficiently extracted. Therefore, the non-aqueous secondary battery of the present invention preferably has a Li supply source (pre-doping Li supply source) for filling the irreversible capacity of SiO _x separately from the positive electrode during assembly.

Examples of the Li supply source include Li metal foil and Li alloy foil (hereinafter collectively referred to as “Li foil”) and the like, and can be in contact with any part of the battery outer body (non-aqueous electrolyte solution). This Li supply source may be arranged at a certain point. Specifically, for example, a Li electrode formed by attaching a Li foil as a Li supply source to a metal foil such as a copper foil as a current collector can be used. By being electrically connected, the Li electrode Li foil functions as a Li supply source. Incidentally, Li source (said Li foil) is, as described above, since the Li ions emitted therefrom is taken into SiO _x to fill the irreversible capacity of SiO _x, in the battery which time the assembly has passed May not exist.

When the non-aqueous secondary battery includes the Li supply source, Li ions supplied from the Li supply source can be taken in with higher uniformity over the entire SiO _x in the negative electrode mixture layer. In view of the above, it is preferable to allow Li ions to pass through the negative electrode current collector. Specifically, the negative electrode current collector has a plurality of through holes penetrating from one side to the other side. Is preferred.

  About the said through-hole of a negative electrode collector, it is preferable that a hole diameter is 10-1000 micrometers, for example. Moreover, in the negative electrode current collector having the through holes, the porosity is preferably 5 to 80%.

  There is no restriction | limiting in particular about arrangement | positioning of the said through-hole in a negative electrode collector, Each through-hole may be arrange | positioned regularly and may be arrange | positioned irregularly, but intensity | strength over the whole negative electrode collector. From the viewpoint of improving the uniformity of the through holes, it is preferable that the through holes are regularly arranged.

  The thickness of the negative electrode mixture layer is preferably 10 to 100 μm per one surface of the current collector, for example.

  Moreover, you may form in the negative electrode the lead body for electrically connecting with the other member in a non-aqueous secondary battery according to a conventional method as needed.

  For the positive electrode according to the nonaqueous secondary battery of the present invention, a positive electrode mixture layer containing a positive electrode active material is used on one or both sides of the positive electrode current collector.

The positive electrode active material includes a lithium-containing composite oxide containing lithium and a transition metal, more specifically, a lithium-containing composite oxide used in a known non-aqueous secondary battery, for example, lithium such as LiCoO ₂ Cobalt oxides; Lithium manganese oxides such as LiMnO ₂ and Li ₂ MnO ₃ ; Lithium nickel oxides such as LiNiO ₂ ; Lithium-containing composite oxides having a layered structure such as LiCo _1-x NiO ₂ ; LiMn ₂ O ₄ , Li _4/3 Ti _5/3 O ₄ or other spinel-structured lithium-containing composite oxides; LiFePO ₄ or other olivine-structured lithium-containing composite oxides; oxides obtained by substituting the above oxides with various elements; Can be used.

  The positive electrode mixture layer usually contains a conductive additive and a binder. The same thing as what was illustrated previously as what can be used for a negative mix layer can be used for the conductive support agent which concerns on a positive mix layer.

  Moreover, PVDF, polytetrafluoroethylene (PTFE), SBR, etc. can be used for the binder which concerns on a positive mix layer.

  For the positive electrode, for example, a paste-like or slurry-like positive electrode mixture-containing composition in which a positive electrode active material, a binder, a conductive auxiliary agent, and the like are dispersed in a solvent such as NMP is prepared (however, the binder is dissolved in the solvent). It may be manufactured through a step of applying a pressing process such as a calendering process, if necessary, after applying this to one or both sides of the current collector and drying it. However, the manufacturing method of the positive electrode is not limited to the above method, and may be manufactured by other manufacturing methods.

  The thickness of the positive electrode mixture layer is preferably, for example, 10 to 100 μm per one side of the current collector. Moreover, as a composition of a positive mix layer, it is preferable that the quantity of a positive electrode active material is 65-98 mass%, for example, it is preferable that the quantity of a binder is 0.5-15 mass%, and a conductive support agent. Is preferably 0.5 to 20% by mass.

  The current collector can be the same as that used for the positive electrode of a conventionally known nonaqueous secondary battery. For example, an aluminum foil having a thickness of 10 to 30 μm is preferable.

  When the non-aqueous secondary battery includes the Li supply source, it is preferable that the positive electrode current collector also has a plurality of through holes penetrating from one side to the other side, like the negative electrode current collector. .

  About the said through-hole of a positive electrode electrical power collector, it is preferable that a hole diameter is 10-1000 micrometers, for example. Moreover, in the positive electrode current collector having the through holes, the porosity is preferably 5 to 80%.

  Moreover, you may form the lead body for electrically connecting with the other member in a non-aqueous secondary battery according to a conventional method as needed.

  In the nonaqueous secondary battery of the present invention, the negative electrode and the positive electrode are a laminated body (laminated electrode body) superposed via a separator, or a wound body (winding electrode) obtained by further winding the laminated body in a spiral shape. Body).

  For the separator, for example, a porous film made of a resin such as polyolefin, polyester, polyimide, polyamide, or polyurethane can be used. From the viewpoint of providing the separator with a shutdown function, a porous film made of polyolefin is used. It is preferable to use it.

  Examples of the polyolefin include polyethylene (PE) such as low density polyethylene, high density polyethylene, and ultrahigh molecular weight polyethylene; polypropylene (PP); etc., and only one of these may be used. You may use together. For example, as a porous film using two or more kinds of polyolefin, for example, a porous film having a three-layer structure in which a PP layer is laminated on a PP layer via a PE layer can be mentioned.

  Among these polyolefins, it is preferable to use those having a melting point, that is, a melting temperature measured by DSC of 80 to 150 ° C. in accordance with JIS K 7121. Such a porous film containing a polyolefin having a melting point can be a separator having a shutdown characteristic starting temperature of 90 to 150 ° C. in which the polyolefin is softened and the pores of the separator are closed. By using the separator, the safety of the non-aqueous secondary battery can be further increased.

  Examples of porous membranes used in separators include ion-permeable porous membranes having a large number of pores formed by a conventionally known solvent extraction method, dry type or wet drawing method (generally used as battery separators). A microporous film) can be used.

  Further, a laminated separator in which a heat-resistant porous layer containing a heat-resistant inorganic filler is formed on the surface of the porous film (microporous film) may be used. When such a stacked separator is used, the shrinkage of the separator is suppressed even when the temperature in the battery rises, and a short circuit due to contact between the positive electrode and the negative electrode can be suppressed. A high non-aqueous secondary battery can be obtained.

  As the inorganic filler to be contained in the heat-resistant porous layer, boehmite, alumina, silica, titanium oxide and the like are preferable, and one or more of these can be used.

  The heat-resistant porous layer preferably contains a binder for binding the inorganic fillers or bonding the heat-resistant porous layer and the microporous film. The binder includes an ethylene-vinyl acetate copolymer (EVA, having a structural unit derived from vinyl acetate of 20 to 35 mol%), an ethylene-acrylic acid copolymer such as an ethylene-ethyl acrylate copolymer, and a fluorine-based rubber. Styrene butadiene rubber (SBR), carboxymethyl cellulose (CMC), hydroxyethyl cellulose (HEC), polyvinyl alcohol (PVA), polyvinyl butyral (PVB), polyvinyl pyrrolidone (PVP), cross-linked acrylic resin, polyurethane, epoxy resin, etc. Are preferred, and one or more of these can be used.

  The content of the inorganic filler in the heat-resistant porous layer is preferably 50% by volume or more in the entire volume of the components constituting the heat-resistant porous layer (in the entire volume excluding the pores), 70 It is more preferable that the volume is not less than volume%, and it is more preferable that the volume be not more than 99 volume% (the remainder may be the above binder).

  The thickness of the separator (a separator made of a microporous membrane made of polyolefin, or the laminated separator) is to reduce the occupancy of the battery internal volume of components that are not involved in the battery reaction and increase the amount of active material of the positive and negative electrodes From the viewpoint of increasing the design capacity and output density of the battery, it is preferably 30 μm or less, and more preferably 16 μm or less. However, from the viewpoint of sufficiently maintaining the strength of the separator, the thickness of the separator is preferably 5 μm or more, and more preferably 10 μm or more.

  In the case of the multilayer separator, the heat-resistant porous layer preferably has a thickness of 1 to 8 μm. Moreover, it is preferable that the porosity of a heat resistant porous layer is 40 to 70%.

  For the non-aqueous electrolyte solution according to the non-aqueous secondary battery of the present invention, a solution prepared by dissolving a lithium salt in the following non-aqueous solvent can be used.

  Examples of the solvent include ethylene carbonate (EC), propylene carbonate (PC), butylene carbonate (BC), dimethyl carbonate (DMC), diethyl carbonate (DEC), methyl ethyl carbonate (MEC), γ-butyrolactone (γ-BL ), 1,2-dimethoxyethane (DME), tetrahydrofuran (THF), 2-methyltetrahydrofuran, dimethyl sulfoxide (DMSO), 1,3-dioxolane, formamide, dimethylformamide (DMF), dioxolane, acetonitrile, nitromethane, Methyl formate, methyl acetate, phosphoric acid triester, trimethoxymethane, dioxolane derivative, sulfolane, 3-methyl-2-oxazolidinone, propylene carbonate derivative, tetrahydrofuran derivative , Can be used diethyl ether, an aprotic organic solvent such as 1,3-propane sultone as a singly mixed solvent or a mixture of two or more.

The lithium salt according to the non-aqueous electrolyte solution, for _{example, LiClO 4, LiPF 6, LiBF} 4, LiAsF 6, LiSbF 6, LiCF 3 SO 3, LiCF 3 CO 2, Li 2 C 2 F 4 (SO 3) 2, At least 1 selected from LiN (CF ₃ SO ₂ ) ₂ , LiC (CF ₃ SO ₂ ) ₃ , LiC _n F _{2n + 1} SO 3 (n ≧ 2), LiN (RfOSO ₂ ) ₂ [where Rf is a fluoroalkyl group] Species are mentioned. The concentration of these lithium salts in the non-aqueous electrolyte is preferably 0.6 to 1.8 mol / l, and more preferably 0.9 to 1.6 mol / l.

  In addition, in the non-aqueous electrolyte, vinylene carbonate, vinyl ethylene carbonate, acid anhydride, sulfonic acid ester, for the purpose of improving the safety such as further improvement of charge / discharge cycle characteristics and high temperature storage property and prevention of overcharge, Additives (including these derivatives) such as dinitrile, 1,3-propane sultone, diphenyl disulfide, cyclohexylbenzene, biphenyl, fluorobenzene, and t-butylbenzene can be added as appropriate.

  Further, as the non-aqueous electrolyte, a gel (gel electrolyte) obtained by adding a known gelling agent such as a polymer can be used.

  It is preferable to use a metal laminate film outer package for the outer package according to the non-aqueous secondary battery of the present invention. Since the metal laminate film outer package is easier to deform than, for example, a metal outer can, the negative electrode mixture layer and the negative electrode current collector are hardly broken even if the negative electrode expands due to battery charging. It is.

  As the metal laminate film constituting the metal laminate film exterior body, for example, a metal laminate film having a three-layer structure composed of exterior resin layer / metal layer / interior resin layer is used.

  The metal layer in the metal laminate film is an aluminum film, a stainless steel film or the like, and the interior resin layer is a heat-sealing resin (for example, a modified polyolefin ionomer that develops heat-fusibility at a temperature of about 110 to 165 ° C.). A structured film may be mentioned. Examples of the exterior resin layer of the metal laminate film include a nylon film (such as nylon 66 film) and a polyester film (such as polyethylene terephthalate film).

  In the metal laminate film, the thickness of the metal layer is preferably 10 to 150 μm, the thickness of the interior resin layer is preferably 20 to 100 μm, and the thickness of the exterior resin layer is preferably 20 to 100 μm.

  The shape of the exterior body is not particularly limited. For example, the shape of the exterior body may be a polygon such as a triangle, a quadrangle, a pentagon, a hexagon, a heptagon, and an octagon in plan view. A square (rectangular or square) is common. The size of the exterior body is not particularly limited, and can be various sizes such as a so-called thin shape and large size.

  The metal laminate film exterior body may be configured by folding a single metal laminate film in two, or may be configured by stacking two metal laminate films.

  When the planar shape of the exterior body is a polygon, the side from which the positive external terminal is drawn out and the side from which the negative external terminal is drawn out may be the same side or different sides.

  The width of the heat fusion part in the outer package is preferably 5 to 20 mm.

  The non-aqueous secondary battery of the present invention is excellent in charge / discharge cycle characteristics and can be made to have a high capacity. In addition to the above, the present invention can be applied to the same applications as various applications to which conventionally known non-aqueous secondary batteries are applied.

  Hereinafter, the present invention will be described in detail based on examples. However, the following examples do not limit the present invention.

Example 1
<Preparation of positive electrode>
LiCoO _{2 as a} positive electrode active material: 96.5 parts by mass, NMP solution containing PVDF as a binder at a concentration of 10% by mass: 20 parts by mass, and acetylene black as a conductive auxiliary agent: 1.5 parts by mass The mixture was kneaded using a twin-screw kneader, and NMP was added to adjust the viscosity to prepare a positive electrode mixture-containing paste. This paste was applied to one or both sides of an aluminum foil (porosity: 15%) having a thickness of 15 μm and provided with through-holes (hole diameter: 300 μm) from one side to the other side, and vacuumed at 120 ° C. for 12 hours. Drying was performed to form a positive electrode mixture layer on one or both sides of the aluminum foil, press treatment was performed, and cutting was performed at a predetermined size to obtain a strip-shaped positive electrode. In addition, when applying the positive electrode mixture-containing paste to the aluminum foil, a part of the aluminum foil is exposed, and the positive electrode mixture-containing paste is applied to both sides of the aluminum foil. The applied part was also made into the application part. The thickness of the positive electrode mixture layer of the obtained positive electrode (in the case where the positive electrode mixture layer was formed on both surfaces of the aluminum foil, the thickness per one surface) was 65 μm.

  Exposure of aluminum foil (positive electrode current collector) to form a strip-shaped positive electrode with a positive electrode mixture layer formed on one side of the aluminum foil and a strip-shaped positive electrode with a positive electrode mixture layer formed on both sides of the aluminum foil as tabs Punch out with a Thomson blade so that a part of the part protrudes and the formation part of the positive electrode mixture layer becomes a substantially square shape with four corners curved, and the positive electrode mixture layer is formed on one side of the positive electrode current collector And a positive electrode for a battery having a positive electrode mixture layer on both surfaces of a positive electrode current collector. FIG. 1 is a plan view schematically showing the battery positive electrode (however, in order to facilitate understanding of the structure of the positive electrode, the size of the positive electrode shown in FIG. 1 does not necessarily match the actual one). Not) The positive electrode 10 has a shape having a tab portion 13 punched out so that a part of the exposed portion of the positive electrode current collector 12 protrudes, and the shape of the formation portion of the positive electrode mixture layer 11 is a substantially rectangular shape with four corners curved. In the figure, the lengths a, b and c were 5 mm, 30 mm and 2 mm, respectively.

<Production of negative electrode>
A composite in which the surface of SiO is coated with carbon (average particle size: 8 μm, the amount of carbon in the composite is 20 mass%, hereinafter referred to as “SiO / carbon composite”) and artificial graphite (average particle size: 20 μm) at a ratio (mass ratio) of 80:20: 90 parts by mass, PAI: 6 parts by mass, PVDF: 1.8 parts by mass, PVP: 0.2 parts by mass, and a conductive assistant Ketjen Black (KB): 2 parts by mass was mixed with NMP to prepare a negative electrode mixture-containing paste.

  The negative electrode mixture-containing paste was applied to both sides of a copper foil (porosity: 35%) having a thickness of 10 μm and provided with through-holes (pore diameter: 100 μm) from one side to the other side, followed by drying. A negative electrode mixture layer was formed on one side or both sides of this, pressed, and cut into a predetermined size to obtain a strip-like negative electrode. In addition, when apply | coating the negative mix containing paste to copper foil, a part of copper foil was exposed and the back surface also made the application part the part made into the application part on the surface. The thickness of the negative electrode mixture layer of the obtained negative electrode (thickness per one side of the copper foil as the negative electrode current collector) was 39 μm. The value of A / (B + C) in the negative electrode mixture layer was 3.

  In order to make the strip-shaped negative electrode into a tab portion, a part of the exposed portion of the copper foil (negative electrode current collector) protrudes, and the negative electrode mixture layer forming portion has a substantially square shape with four corners curved. Then, a negative electrode for a battery having a negative electrode mixture layer on both surfaces of the negative electrode current collector was obtained. FIG. 2 is a plan view schematically showing the battery negative electrode (however, in order to facilitate understanding of the structure of the negative electrode, the size of the negative electrode shown in FIG. 2 does not necessarily match the actual size). Not) The negative electrode 20 has a shape having a tab portion 23 punched out so that a part of the exposed portion of the negative electrode current collector 22 protrudes, and the shape of the forming portion of the negative electrode mixture layer 21 is a substantially rectangular shape with four corners curved. In the figure, the lengths d, e, and f were 6 mm, 31 mm, and 2 mm, respectively.

<Preparation of Li electrode for Li supply source>
Using a Thomson blade used in the production of the negative electrode, a 6 μm thick copper foil was punched into the same shape as the negative electrode for the battery, and a Li metal foil having a width of 3 mm, a length of 25 mm, and a thickness of 230 μm was prepared. A Li electrode for Li supply source was produced by pressure bonding on one side.

<Battery assembly>
Two positive electrodes for a battery with a positive electrode mixture layer formed on one side of the positive electrode current collector, 14 positive electrodes for a battery with a positive electrode mixture layer formed on both sides of the positive electrode current collector, and a negative electrode mixture on both sides of the negative electrode current collector A laminate was formed using 15 negative electrodes for a battery on which an agent layer was formed. In the laminate, the upper and lower ends are arranged as positive electrodes for a battery in which a positive electrode mixture layer is formed on one side of the positive electrode current collector, and the current collectors are arranged so as to face the outside, and the negative electrode current collector is interposed therebetween. The negative electrode for a battery having a negative electrode mixture layer formed on both sides thereof and the positive electrode for a battery having a positive electrode mixture layer formed on both sides of the positive electrode current collector are alternately arranged, and a PE made between each positive electrode and each negative electrode. A separator (thickness 16 μm) was interposed.

  Two Li electrodes for the Li supply source were prepared, and the respective Li electrodes were stacked on the upper and lower ends of the laminate through PE separators (thickness: 16 μm). In addition, each Li electrode was arrange | positioned so that the Li metal foil side might face the separator side.

All positive electrode tab portions of the laminate were collected and welded, and all negative electrode tab portions and all Li electrode tab portions were collected and welded to obtain a laminated electrode body. And the said laminated electrode body is inserted in the said hollow of the aluminum laminate film of thickness: 0.15mm, width: 34mm, and height: 50mm which formed the hollow so that the said laminated electrode body might be accommodated, and said and above An aluminum laminate film of the same size was placed and three sides of both aluminum laminate films were heat-welded. Then, from the remaining one side of both aluminum laminate films, LiPF ₆ is dissolved at a concentration of 1 mol / l in a non-aqueous electrolyte (a mixed solvent having a volume ratio of EC and DEC of 3: 7), and 3 mass of vinylene carbonate is further added. % And a solution in which fluoroethylene carbonate is added in an amount of 2% by mass) was injected. Thereafter, the remaining one side of both aluminum laminate films was vacuum-sealed to produce a non-aqueous secondary battery having the cross-sectional structure shown in FIG. 4 with the appearance shown in FIG. The prepared battery was stored at room temperature for 2 weeks for pre-doping of Li into the negative electrode.

  Here, FIG. 3 and FIG. 4 will be described. FIG. 3 is a plan view schematically showing a non-aqueous secondary battery, and FIG. 4 is a cross-sectional view taken along the line II in FIG. The nonaqueous secondary battery 100 includes a laminated electrode body 102 constituted by laminating a positive electrode and a negative electrode with a separator in an aluminum laminated film outer package 101 constituted by two aluminum laminated films, and a nonaqueous electrolytic solution. (Not shown) is housed, and the aluminum laminate film outer package 101 is sealed by heat-sealing the upper and lower aluminum laminate films at the outer peripheral portion thereof. In FIG. 4, in order to avoid complication of the drawing, each layer constituting the aluminum laminate film outer package 101 and the positive electrode, negative electrode, separator and Li electrode constituting the laminated electrode body are distinguished. Not shown.

  Each positive electrode of the laminated electrode body 102 is integrated by welding the tab portions together, and the integrated product of the welded tab portions is connected to the positive electrode external terminal 103 in the battery 100, although not shown. Each negative electrode (and each Li electrode) of the laminated electrode body 102 is also integrated by welding the tab portions, and the integrated product of the welded tab portions is connected to the negative electrode external terminal 104 in the battery 100. The positive electrode external terminal 103 and the negative electrode external terminal 104 are drawn out to the outside of the aluminum laminate film exterior body 101 so that they can be connected to an external device or the like.

Examples 2-12 and Comparative Examples 1-10
The content of each component in the negative electrode mixture layer, the thickness of the negative electrode mixture layer per one side of the negative electrode current collector, and the thickness of the Li metal foil in the Li electrode are changed as described in Tables 1 to 4 below. A negative electrode was produced in the same manner as in Example 1 except that the above was performed, and a nonaqueous secondary battery was produced in the same manner as in Example 1 except that these negative electrodes were used.

  In Tables 2 and 4, “the thickness of the negative electrode mixture layer” means the thickness of one surface of the negative electrode current collector as described above (the same applies to Table 8 described later).

  In the non-aqueous secondary batteries of Examples 1 to 12 and Comparative Examples 1 to 10, the thickness of the negative electrode mixture layer (the negative electrode in the negative electrode mixture layer was set so that the 0.2C discharge capacity described later was 200 mAh. The amount of the active material) was adjusted, and the thickness of the Li metal foil related to the Li electrode was adjusted in accordance with the negative electrode so that the initial charge / discharge efficiency described later was 94%.

  The following evaluation was performed about the non-aqueous secondary battery of Examples 1-12 and Comparative Examples 1-10.

<Measurement of initial charge / discharge efficiency and 0.2C discharge capacity>
Each non-aqueous secondary battery is charged at a constant current until the voltage reaches 4.4 V at a current value of 0.5 C, and then charged at a constant voltage of 4.4 V until the current value reaches 0.05 C. I went to find the initial charge capacity. About each battery after charge, constant current discharge was performed until the voltage became 2.0V with the electric current value of 0.2C, and the first time discharge capacity (0.2C discharge capacity) was calculated | required. And the value which remove | divided the first time discharge capacity by the first time charge capacity was represented by percentage, and the first time charge / discharge efficiency of each battery was computed.

<Charge / discharge cycle characteristics evaluation>
Each non-aqueous secondary battery is charged at a constant current until the voltage reaches 4.4 V at a current value of 1 C, following the discharge for measuring the 0.2 C discharge capacity, and is further set to a constant voltage of 4.4 V. After performing voltage charging until the current value reaches 0.05C, a series of operations for performing constant current discharge at a current value of 1C until the voltage reaches 2.0V is repeated, and a current value of 0.5C is repeated for the 199th time. Then, charging is performed at a constant current until the voltage reaches 4.4V, and then charging at a constant voltage of 4.4V is performed until the current value reaches 0.05C, and then the voltage reaches 2.C at a current value of 0.2C. The constant current discharge was performed until it became 0V. The discharge capacity in the final cycle of constant current-constant voltage charge and constant current discharge is expressed as a percentage obtained by dividing the initial discharge capacity by the 0.2C discharge capacity to obtain the capacity maintenance rate, and the charge / discharge cycle of each battery Characteristics were evaluated.

  The evaluation results are shown in Tables 5 and 6.

  As shown in Table 5, PAI, PVDF, and PVP, which are imide binders, were used as binders, and the content relationship “A / (B + C)” in these negative electrode mixture layers was set to an appropriate value. The non-aqueous secondary batteries of Examples 1 to 12 using a high capacity retention rate at the time of charge / discharge cycle characteristics evaluation had excellent charge / discharge cycle characteristics.

  On the other hand, as shown in Table 6, the batteries of Comparative Examples 1 to 8 using a negative electrode with an inappropriate relationship of “A / (B + C)”, the battery of Comparative Example 9 using a negative electrode not using PVP, And the battery of the comparative example 10 using the negative electrode which does not use PVDF had the capacity maintenance rate at the time of charging / discharging cycling characteristics evaluation lower than the battery of an Example, and its charging / discharging cycling characteristics were inferior.

Example 13
A negative electrode was produced in the same manner as in Example 4 except that PI was used instead of PAI, and a nonaqueous secondary battery was produced in the same manner as in Example 4 except that this negative electrode was used.

Example 14 and Comparative Examples 11 and 12
The content of each component in the negative electrode mixture layer, the thickness of the negative electrode mixture layer per one side of the negative electrode current collector, and the thickness of the Li metal foil in the Li electrode were changed as described in Tables 7 and 8 below. A negative electrode was produced in the same manner as in Example 13, and a non-aqueous secondary battery was produced in the same manner as in Example 13 except that these negative electrodes were used.

  For the nonaqueous secondary batteries of Examples 13 and 14 and Comparative Examples 11 and 12, the same evaluation as the battery of Example 1 and the like was performed. These results are shown in Table 9.

  As shown in Table 9, even when PI was used for the imide-based binder, the non-aqueous solutions of Examples 13 and 14 using negative electrodes in which “A / (B + C)” in the negative electrode mixture layer was set to an appropriate value. The secondary battery had a higher capacity retention rate at the time of evaluation of charge / discharge cycle characteristics than the batteries of Comparative Examples 11 and 12 where these values were inappropriate, and had excellent charge / discharge cycle characteristics.

DESCRIPTION OF SYMBOLS 10 Positive electrode 11 Positive electrode mixture layer 12 Positive electrode collector 13 Tab part 20 Negative electrode 21 Negative electrode mixture layer 22 Negative electrode collector 23 Tab part 100 Nonaqueous secondary battery 101 Metal laminate film exterior body 102 Laminated electrode body 103 Positive electrode external terminal 104 Negative external terminal

Claims (3)

A positive electrode having a positive electrode mixture layer containing a positive electrode active material on one or both sides of a current collector, a negative electrode having a negative electrode mixture layer containing a negative electrode active material and a binder on one or both sides, a separator, and a non-electrode A non-aqueous secondary battery provided with a water electrolyte,
The positive electrode mixture layer contains a lithium-containing composite oxide containing lithium and a transition metal as a positive electrode active material,
The negative electrode mixture layer is a negative electrode made of a composite of a material containing Si and O as constituent elements (provided that the atomic ratio x of O to Si is 0.5 ≦ x ≦ 1.5) and a carbon material. An imide-based binder that is contained as an active material and is at least one of polyamide-imide and polyimide, polyvinylidene fluoride, and polyvinylpyrrolidone as a binder, the imide-based binder, the polyvinylidene fluoride, and the polyvinyl the content in the negative electrode material mixture layer pyrrolidone, a (mass%), respectively, when the B (wt%) and C (mass%), meets the 1 ≦ {a / (B + C)} ≦ 5, wherein A nonaqueous secondary battery, wherein the content A of the imide binder in the negative electrode mixture layer is 0.5 to 25% by mass . The non-aqueous secondary battery according to claim 1 , wherein a content B of the polyvinylidene fluoride in the negative electrode mixture layer is 0.45 to 4 mass%. The nonaqueous secondary battery according to claim 1 or 2 content of the polyvinylpyrrolidone in the negative electrode mixture layer C is from 0.05 to 1 mass%.

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