JP5424011B2 - SECONDARY BATTERY AND ITS MANUFACTURING METHOD, SECONDARY BATTERY ANODE AND SECONDARY BATTERY POSITIVE - Google Patents

Description

  The present invention relates to a secondary battery including an electrolyte together with a positive electrode and a negative electrode, a manufacturing method thereof, and a negative electrode, a positive electrode, and an electrolyte used in an electrochemical device such as a secondary battery.

  In recent years, portable electronic devices such as a video camera, a digital still camera, a mobile phone, and a laptop computer have been widely used, and there is a strong demand for miniaturization, weight reduction, and long life. Accordingly, as a power source, development of a battery, in particular, a secondary battery that is lightweight and capable of obtaining a high energy density is in progress.

  Among them, secondary batteries (so-called lithium ion secondary batteries) that use insertion and extraction of lithium ions for charge / discharge reactions are widely put into practical use because they provide higher energy density than lead batteries and nickel cadmium batteries. .

  A lithium ion secondary battery includes an electrolyte together with a positive electrode and a negative electrode. The positive electrode has a positive electrode active material layer containing a positive electrode active material on a positive electrode current collector. The negative electrode has a negative electrode active material layer containing a negative electrode active material on a negative electrode current collector. The electrolyte includes a solvent and an electrolyte salt dissolved in the solvent.

  Carbon materials such as graphite are widely used as the negative electrode active material. This is because a carbon material has a very small change in crystal structure during insertion and extraction of lithium ions, so that battery capacity and the like can be stably obtained.

  In addition, recently, with the improvement in performance and multi-functionality of portable electronic devices, there has been a demand for further improvement in battery capacity. Therefore, instead of carbon materials, high-capacity materials such as silicon or tin can be used. It is being considered. This is because the theoretical capacity of silicon (4199 mAh / g) or the theoretical capacity of tin (994 mAh / g) is much larger than the theoretical capacity of graphite (372 mAh / g), so that significant improvement in battery capacity can be expected.

  However, in the lithium ion secondary battery, since the negative electrode active material that occludes lithium ions during charge and discharge becomes highly active, the electrolyte is easily decomposed and part of the lithium ions is easily inactivated. As a result, when charge and discharge are repeated, the discharge capacity tends to decrease, and it is difficult to obtain sufficient cycle characteristics. This problem is particularly noticeable when a high-capacity material is used as the negative electrode active material.

Therefore, various ideas have been made to improve battery characteristics such as cycle characteristics. Specifically, a technique for containing perfluoropolyether in the electrolyte (for example, see Patent Documents 1 and 2), and a technique for forming a film containing perfluoropolyether on the surface of the negative electrode (for example, Patent Document 3). See) has been proposed. In addition, a technique for coating the surface of the negative electrode with a polymer material such as a homopolymer or copolymer of vinylidene fluoride (for example, see Patent Document 4), a technique for containing polyvinylidene fluoride or the like in the negative electrode active material (for example, (See Patent Document 5).
JP 2002-305023 A JP 2006-269374 A JP 2004-265609 A JP-T-2006-517719 JP 2007-095563 A

  In recent years, portable electronic devices have become more sophisticated and multifunctional, and their power consumption tends to increase. Therefore, charging and discharging of lithium ion secondary batteries are frequently repeated, and the cycle characteristics are likely to deteriorate. It is in. For this reason, further improvement in cycle characteristics is desired.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a secondary battery capable of improving cycle characteristics, a manufacturing method thereof, a negative electrode, a positive electrode, and an electrolyte.

The secondary battery of the present invention includes a positive electrode including a positive electrode active material capable of occluding and releasing an electrode reactant, a negative electrode including a negative electrode active material capable of occluding and releasing an electrode reactant, and non-aqueous and an electrolyte containing a solvent and an electrolyte salt, at least one of the positive and negative electrodes are those containing at least one of fluorine resin represented by the formula (1) and (2). In addition, the method for manufacturing a secondary battery of the present invention includes a positive electrode including a positive electrode active material capable of occluding and releasing an electrode reactant, and a negative electrode active material capable of occluding and releasing an electrode reactant. at least one of the negative electrode, is obtained so as to contain at least one of fluorine resin shown in formula (1) and (2).

（Ｘ１およびＸ２のそれぞれはパーフルオロアルキル基、カルボン酸アルカリ金属塩基、スルホン酸アルカリ金属塩基、カルボン酸アルカリ土類金属塩基あるいはスルホン酸アルカリ土類金属塩基である。ただし、Ｘ１およびＸ２のうちの少なくとも一方はカルボン酸アルカリ金属塩基、スルホン酸アルカリ金属塩基、カルボン酸アルカリ土類金属塩基あるいはスルホン酸アルカリ土類金属塩基である。ｈおよびｋはｈ＞０、ｋ＞０およびｈ＋ｋ＝１を満たす。）

( Each of X1 and X2 is a perfluoroalkyl group, a carboxylic acid alkali metal base, a sulfonic acid alkali metal base, a carboxylic acid alkaline earth metal base, or a sulfonic acid alkaline earth metal base. At least one is a carboxylic acid alkali metal base, a sulfonic acid alkali metal base, a carboxylic acid alkaline earth metal base, or a sulfonic acid alkaline earth metal base, h and k satisfy h> 0, k> 0, and h + k = 1 . .)

（Ｘ３はカルボン酸アルカリ金属塩基、スルホン酸アルカリ金属塩基、カルボン酸アルカリ土類金属塩基あるいはスルホン酸アルカリ土類金属塩基である。）

(X3 is a carboxylic acid alkali metal base , a sulfonic acid alkali metal base , a carboxylic acid alkaline earth metal base, or a sulfonic acid alkaline earth metal base .)

The negative electrode for secondary battery of the present invention has a negative electrode film formed on the negative electrode active material layer after the negative electrode active material layer is formed on the negative electrode current collector, and the negative electrode active material layer is an electrode reactant. The negative electrode active material which can occlude and discharge | release is contained, and a negative electrode film contains at least 1 sort (s) of the fluororesin shown to Formula (1) and Formula (2).

The positive electrode for a secondary battery of the present invention has a positive electrode active material layer formed on a positive electrode current collector and then a positive electrode film formed on the positive electrode active material layer, and the positive electrode active material layer is an electrode reactant. A positive electrode active material capable of occluding and releasing hydrogen, and the positive electrode film contains at least one of fluororesins represented by the formulas (1) and (2).

According to the positive electrode for a negative electrode or a rechargeable battery for a secondary battery of the present invention, since to include at least one of fluorine resin shown in Formula (1) and (2), their chemical Stability is improved. Accordingly, during the electrode reaction, the electrode reactant is easily occluded and released in the negative electrode or the positive electrode, and the decomposition reaction of the electrolyte is suppressed. Therefore, according to the secondary battery of the present invention or the manufacturing method thereof, cycle characteristics can be improved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  A secondary battery according to an embodiment of the present invention includes an electrolyte together with a positive electrode and a negative electrode. The positive electrode includes a positive electrode active material capable of occluding and releasing an electrode reactant, and the negative electrode includes a negative electrode active material capable of occluding and releasing an electrode reactant. The electrolyte contains a solvent and an electrolyte salt dissolved in the solvent. In particular, at least one of the positive electrode, the negative electrode, and the electrolyte includes at least one of fluororesins represented by the formula (1) or the formula (2) (hereinafter, also simply referred to as “fluororesin”). It is out.

（Ｘ１およびＸ２のうちの少なくとも一方はカルボン酸金属塩基あるいはスルホン酸金属塩基である。ｈおよびｋは比率を表し、ｈ＋ｋ＝１である。）

(At least one of X1 and X2 is a carboxylate metal base or a sulfonate metal base. H and k represent a ratio, and h + k = 1.)

（Ｘ３はカルボン酸金属塩基あるいはスルホン酸金属塩基である。）

(X3 is a carboxylate metal base or a sulfonate metal base.)

  When the positive electrode contains a fluororesin, for example, the fluororesin is introduced into the positive electrode as a coating. Specifically, for example, when the positive electrode has a positive electrode active material layer on the positive electrode current collector, a positive electrode film containing a fluororesin is provided on the positive electrode active material layer.

  When the negative electrode includes a fluororesin, for example, the fluororesin is introduced into the negative electrode as a coating, as in the case of the positive electrode described above. Specifically, for example, when the negative electrode has a negative electrode active material layer on the negative electrode current collector, a negative electrode film containing a fluororesin is provided on the negative electrode active material layer.

  In addition, for example, a fluororesin may be introduced into the positive electrode or the negative electrode as a particle coating film. Specifically, for example, when the positive electrode active material or the negative electrode active material has a plurality of particles, a particle coating film containing a fluororesin is provided so as to cover the surface of the positive electrode active material or the negative electrode active material. May be.

  When the electrolyte contains a fluororesin, for example, the fluororesin is introduced into the electrolyte as an additive. Specifically, for example, a fluororesin is dissolved or dispersed in an electrolyte solvent. In this case, all of the fluororesin may be dissolved, or only part of it may be dissolved.

  The reason why at least one of the positive electrode, the negative electrode, and the electrolyte contains the fluororesin is that the chemical stability of the object containing the fluororesin is improved. Specifically, when the positive electrode or the negative electrode contains a fluororesin, the film containing the fluororesin functions as a protective film, so that the positive electrode or the negative electrode is chemically stabilized. Thereby, during charge and discharge, the electrode reactant is easily occluded and released in the positive electrode or the negative electrode, and the decomposition reaction of the electrolyte is suppressed. On the other hand, when the electrolyte contains a fluororesin, the fluororesin functions as a stabilizer, so that the electrolyte is chemically stabilized. Thereby, the decomposition reaction of the electrolyte is suppressed during charging and discharging.

  Since at least one of the positive electrode, the negative electrode, and the electrolyte contains a fluororesin, the target containing the fluororesin may be only one of the positive electrode, the negative electrode, or the electrolyte, Any two of them may be combined, or all of them may be used.

  Of the positive electrode, the negative electrode, and the electrolyte, the larger the number of objects containing a fluororesin, the better. This is because a higher effect can be obtained. In addition, when only any one of a positive electrode, a negative electrode, and electrolyte contains a fluororesin, the object containing the fluororesin is preferable in order of an electrolyte, a positive electrode, and a negative electrode. This is because a higher effect is obtained in the electrode (positive electrode, negative electrode) than in the electrolyte, and a higher effect is obtained in the negative electrode than in the positive electrode. In addition, when any two of the positive electrode, the negative electrode, and the electrolyte contain a fluororesin, the target containing the fluororesin is preferably the positive electrode and the negative electrode. This is because a higher effect can be obtained in the electrode than in the electrolyte.

The fluororesin represented by the formula (1) is based on a perfluoroether bond having two types of repeating units (—O—CF ₂ —CF ₂ — and —O—CF ₂ —), and has at least one terminal thereof. X1 and X2 are compounds having a carboxylate metal base or a sulfonate metal base. Further, the fluororesin represented by the formula (2) is a compound having a perfluoroether bond having no repeating unit as a base, and having a carboxylate metal base or a sulfonate metal base as X3 at one end thereof. The carboxylate metal base is a group represented by -C (= O) -OM (M is a metal element), and the sulfonate metal base is represented by -S (= O) _2- OM. It is a group.

  In the fluororesins represented by the formulas (1) and (2), the type of the metal base is not particularly limited. Among them, an alkali metal salt or an alkaline earth metal salt is preferable, and an alkali metal salt is preferable. Is more preferable. This is because a higher effect can be obtained. The “alkaline earth metal” in the present invention includes beryllium (Be) and magnesium (Mg), that is, a Group 2 element in the long-period periodic table. Specifically, group 2 elements are beryllium, magnesium, calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra). This long-period type periodic table is represented by a revised inorganic chemical nomenclature proposed by IUPAC (International Pure and Applied Chemical Association).

  Moreover, it is preferable that the kind of metal base is the same kind of metal base as an electrode reactant, for example. Specifically, for example, when the electrode reactant is lithium ion, the metal base is preferably a lithium salt. This is because a higher effect can be obtained.

  In the fluororesin represented by the formula (1), when both X1 and X2 are carboxylic acid metal bases or sulfonic acid metal bases, both X1 and X2 may be carboxylic acid metal bases, May be a sulfonic acid metal base or a carboxylic acid metal base and a sulfonic acid metal base, respectively. Of course, when both X1 and X2 are carboxylic acid metal bases or sulfonic acid metal bases, their types (metal element types) may be the same or different. Especially, it is preferable that all of X1 and X2 are carboxylic acid metal bases. This is because a higher effect can be obtained.

When only one of X1 and X2 is a carboxylic acid metal base or a sulfonic acid metal base, the other may be any group. Examples of the other group in this case include a perfluoroalkyl group such as a trifluoromethyl group (—CF ₃ ).

  In addition, the molecular weight (for example, number average molecular weight) of the fluororesin shown in Formula (1) is not particularly limited, and can be arbitrarily set according to conditions such as dispersibility (or solubility) in a solvent for dispersion. . Further, the ratio of h and k (h: k) is not particularly limited, but for example, preferably h> k. This is because a higher effect can be obtained.

  In the fluororesin represented by the formula (2), X3 may be either a carboxylic acid metal base or a sulfonic acid metal base, and among them, a carboxylic acid metal base is preferable. This is because a higher effect can be obtained.

  Specific examples of the fluororesin shown in Formula (1) include compounds represented by Formula (1-1) to Formula (1-6). Of these, compounds represented by formula (1-1) or formula (1-2) in which X1 and X2 are the same are preferred, and compounds represented by formula (1-1) in which X1 and X2 are carboxylic acid metal bases are preferred. More preferred.

  Specific examples of the fluororesin represented by Formula (2) include compounds having structures represented by Formula (2-1) to Formula (2-4). Especially, the compound shown to Formula (2-1) or Formula (2-2) is preferable, and the compound shown to Formula (2-1) whose X3 is a carboxylate metal base is more preferable.

  Regarding the presence or absence of fluororesin and its chemical structure, for example, X-ray photoelectron spectroscopy (XPS) is used to analyze the type and bonding state of elements in the positive electrode, negative electrode or electrolyte. This can be specified.

  This secondary battery is manufactured by forming or preparing at least one of a positive electrode, a negative electrode, and an electrolyte so as to contain a fluororesin.

  Specifically, when the positive electrode or the negative electrode contains a fluororesin, for example, a solution containing a fluororesin is used. That is, when the positive electrode contains a fluororesin, for example, by immersing the positive electrode active material layer in a solution containing the fluororesin, or by applying a solution containing the fluororesin to the surface of the positive electrode active material layer, A positive electrode film containing a fluororesin is formed. When the negative electrode contains a fluororesin, for example, the negative electrode active material layer is immersed in a solution containing the fluororesin or a solution containing the fluororesin is added to the negative electrode active material layer by the same procedure as that of the positive electrode described above. The negative electrode film containing the fluororesin is formed by applying to the surface. In these cases, since the fluororesin contains a carboxylic acid metal base or a sulfonic acid metal base and is so-called water-soluble, water or the like can be used as a solvent for dispersing the fluororesin. For this reason, the cost of the dispersion solvent can be reduced, and an exhaust facility or the like is unnecessary.

  When the electrolyte contains a fluororesin, the fluororesin is dissolved or dispersed in the solvent, and then the electrolyte salt is dissolved in the solvent.

  According to the secondary battery and the manufacturing method thereof, at least one of the positive electrode, the negative electrode, and the electrolyte contains at least one of the fluororesins shown in the formula (1) and the formula (2). The chemical stability of the object containing the fluororesin is improved. Therefore, cycle characteristics can be improved.

  In this case, if a solution containing a fluororesin is used to form the positive electrode and the negative electrode, the positive electrode or the negative electrode containing the fluororesin is used as compared with the case where a method requiring special environmental conditions such as a reduced pressure environment is used. Can be produced stably and easily.

  In particular, if the fluororesin is a compound represented by formula (1-1) or formula (2-1), excellent cycle characteristics can be obtained.

  Next, details of the secondary battery according to the present embodiment will be described with reference to specific examples.

  The secondary battery described here is, for example, a lithium ion secondary battery in which the capacity of the negative electrode is expressed based on insertion and extraction of lithium ions that are electrode reactants.

(First secondary battery)
1 and 2 show a cross-sectional configuration of the first secondary battery, and FIG. 2 shows an enlarged part of the spirally wound electrode body 20 shown in FIG. In the first secondary battery, for example, among the positive electrode 21, the negative electrode 22, and the electrolyte, the negative electrode 22 includes a fluororesin.

  This secondary battery mainly includes a wound electrode body 20 in which a positive electrode 21 and a negative electrode 22 are laminated and wound through a separator 23 inside a substantially hollow cylindrical battery can 11 and a pair of insulating plates. 12 and 13 are accommodated. The battery structure using the cylindrical battery can 11 is called a cylindrical type.

  The battery can 11 has, for example, a hollow structure in which one end is closed and the other end is opened, and is made of a metal material such as iron, aluminum, or an alloy thereof. In addition, when the battery can 11 is comprised with iron, plating, such as nickel, may be given, for example. The pair of insulating plates 12 and 13 are arranged so as to sandwich the wound electrode body 20 from above and below and to extend perpendicularly to the wound peripheral surface.

  A battery lid 14 and a safety valve mechanism 15 and a heat sensitive resistance element (Positive Temperature Coefficient: PTC element) 16 provided inside the battery can 11 are caulked through a gasket 17 at the open end of the battery can 11. It is attached. Thereby, the inside of the battery can 11 is sealed. The battery lid 14 is made of, for example, a metal material similar to that of the battery can 11. The safety valve mechanism 15 is electrically connected to the battery lid 14 via the heat sensitive resistance element 16. In the safety valve mechanism 15, when the internal pressure becomes a certain level or more due to an internal short circuit or external heating, the disk plate 15 </ b> A is reversed and the electric power between the battery lid 14 and the wound electrode body 20 is reversed. Connection is cut off. The heat-sensitive resistor element 16 is configured to prevent abnormal heat generation caused by a large current by limiting the current by increasing the resistance in response to a rise in temperature. The gasket 17 is made of, for example, an insulating material, and for example, asphalt is applied to the surface thereof.

  For example, a center pin 24 is inserted into the winding center of the wound electrode body 20. In the wound electrode body 20, a positive electrode lead 25 made of a metal material such as aluminum is connected to the positive electrode 21, and a negative electrode lead 26 made of a metal material such as nickel is connected to the negative electrode 22. . The positive electrode lead 25 is welded to the safety valve mechanism 15 and electrically connected to the battery lid 14, and the negative electrode lead 26 is welded to the battery can 11 and electrically connected thereto.

  For example, the positive electrode 21 is obtained by providing a positive electrode active material layer 21B on both surfaces of a positive electrode current collector 21A having a pair of surfaces. However, the positive electrode active material layer 21B may be provided only on one surface of the positive electrode current collector 21A.

  The positive electrode current collector 21A is made of, for example, a metal material such as aluminum, nickel, or stainless steel (SUS).

  The positive electrode active material layer 21B contains one or more positive electrode materials capable of occluding and releasing lithium ions as a positive electrode active material, and a positive electrode binder or a positive electrode conductive material as necessary. Other materials such as agents may be included.

As a positive electrode material capable of inserting and extracting lithium ions, for example, a lithium-containing compound is preferable. This is because a high energy density can be obtained. Examples of the lithium-containing compound include a composite oxide having lithium and a transition metal element as constituent elements, and a phosphate compound having lithium and a transition metal element as constituent elements. Especially, what has at least 1 sort (s) of cobalt, nickel, manganese, and iron as a transition metal element is preferable. This is because a higher voltage can be obtained. The chemical formula is represented by, for example, Li _x M1O ₂ or Li _y M2PO ₄ . In the formula, M1 and M2 represent one or more transition metal elements. The values of x and y vary depending on the charge / discharge state, and are generally 0.05 ≦ x ≦ 1.10 and 0.05 ≦ y ≦ 1.10.

Examples of the composite oxide having lithium and a transition metal element include lithium cobalt composite oxide (Li _x CoO ₂ ), lithium nickel composite oxide (Li _x NiO ₂ ), and lithium nickel cobalt composite oxide (Li _x Ni). _1-z Co _z O ₂ (z <1)), lithium nickel cobalt manganese composite oxide (Li _x Ni _(1-vw) Co _v Mn _w O ₂ (v + w <1)), or lithium having a spinel structure Manganese composite oxide (LiMn ₂ O ₄ ) and the like can be mentioned. Among these, a complex oxide having cobalt is preferable. This is because high battery capacity is obtained and excellent cycle characteristics are also obtained. Further, as the lithium cobalt composite oxide, a composite oxide in which a part of cobalt is replaced with aluminum and magnesium (Mg) (LiCo _(1-jk) Al _j Mg _k O ₂ (0 <j <0.1, 0 <K <0.1)). Furthermore, examples of the phosphate compound having lithium and a transition metal element include a lithium iron phosphate compound (LiFePO ₄ ) or a lithium iron manganese phosphate compound (LiFe _1-u Mn _u PO ₄ (u <1)). Is mentioned.

  Other positive electrode materials capable of inserting and extracting lithium ions include, for example, oxides such as titanium oxide, vanadium oxide and manganese dioxide, disulfides such as titanium disulfide and molybdenum sulfide, and selenization. Examples thereof include chalcogenides such as niobium, and conductive polymers such as sulfur, polyaniline and polythiophene.

  Of course, the positive electrode material capable of inserting and extracting lithium ions may be other than the above. Further, two or more kinds of the series of positive electrode materials may be mixed in any combination.

  Examples of the positive electrode conductive agent include carbon materials such as graphite, carbon black, acetylene black, and ketjen black. These may be used alone or in combination. The positive electrode conductive agent may be a metal material or a conductive polymer as long as it is a conductive material.

  Examples of the positive electrode binder include synthetic rubbers such as styrene butadiene rubber, fluorine rubber, and ethylene propylene diene, and polymer materials such as polyvinylidene fluoride. These may be single and multiple types may be mixed.

  In the negative electrode 22, for example, a negative electrode active material layer 22B and a negative electrode film 22C are provided in this order on both surfaces of a negative electrode current collector 22A having a pair of surfaces. However, the negative electrode active material layer 22B may be provided only on one surface of the negative electrode current collector 22A. The same applies to the anode coating 22C.

  The anode current collector 22A is preferably made of a material having good electrochemical stability, electrical conductivity, and mechanical strength. Examples of such a material include metal materials such as copper, nickel, and stainless steel, and copper is preferable. This is because high electrical conductivity can be obtained.

  In particular, the material constituting the anode current collector 22A preferably has any one or more metal elements that do not form an intermetallic compound with lithium ions that are electrode reactants as constituent elements. When an intermetallic compound is formed with lithium ions, it is easily affected by the stress associated with the expansion and contraction of the negative electrode active material layer 22B during charge and discharge. This is because there is a possibility of peeling from the negative electrode current collector 22A. Examples of such metal elements include copper, nickel, titanium (Ti), iron, and chromium (Cr).

  In addition, the material constituting the anode current collector 22A preferably has any one or more metal elements alloyed with the anode active material layer 22B as constituent elements. This is because the adhesion between the negative electrode current collector 22A and the negative electrode active material layer 22B is improved, so that the negative electrode active material layer 22B is difficult to peel from the negative electrode current collector 22A. Examples of the metal element that does not form an intermetallic compound with lithium ions and is alloyed with the negative electrode active material layer 22B include copper, nickel, and iron. These metal elements are also preferable from the viewpoints of physical strength and conductivity.

  The negative electrode current collector 22A may have a single layer structure or a multilayer structure. In the case where the negative electrode current collector 22A has a multilayer structure, for example, it is preferable that a layer adjacent to the negative electrode active material layer 22B is made of a material alloyed therewith, and a non-adjacent layer is made of another material.

  The surface of the negative electrode current collector 22A is preferably roughened. This is because the so-called anchor effect improves the adhesion between the negative electrode current collector 22A and the negative electrode active material layer 22B. In this case, the surface of the negative electrode current collector 22A only needs to be roughened at least in a region facing the negative electrode active material layer 22B. Examples of the roughening method include a method of forming fine particles by electrolytic treatment. This electrolytic treatment is a method of forming irregularities on the surface of the anode current collector 22A by forming fine particles on the surface of the anode current collector 22A using an electrolytic method in an electrolytic bath. The copper foil produced using electrolytic treatment is generally called “electrolytic copper foil”.

  The negative electrode active material layer 22B contains one or more negative electrode materials capable of occluding and releasing lithium ions as a negative electrode active material, and a negative electrode conductive agent or a negative electrode binder as required. Other materials such as agents may be included. Note that details regarding the negative electrode conductive agent and the negative electrode binder are the same as, for example, the description of the positive electrode conductive agent and the positive electrode binder, respectively.

  Examples of the negative electrode material include materials that can occlude and release lithium ions and have at least one of a metal element and a metalloid element as a constituent element. This is because a high energy density can be obtained. Such a material may be a metal element or metalloid element alone, an alloy or a compound, and may have at least a part of one or two or more phases thereof. The “alloy” in the present invention includes an alloy containing one or more metal elements and one or more metalloid elements in addition to an alloy composed of two or more metal elements. Further, the “alloy” may contain a nonmetallic element. This structure includes a solid solution, a eutectic (eutectic mixture), an intermetallic compound, or a structure in which two or more of them coexist.

  Examples of the metal element or metalloid element described above include a metal element or metalloid element capable of forming an alloy with lithium. Specifically, magnesium (Mg), boron (B), aluminum, gallium (Ga), indium (In), silicon, germanium, tin, lead (Pb), bismuth (Bi), cadmium (Cd), silver ( Ag), zinc, hafnium (Hf), zirconium (Zr), yttrium (Y), palladium (Pd) or platinum (Pt). Among these, at least one of silicon and tin is preferable, and silicon is more preferable. This is because the ability to occlude and release lithium ions is large, so a high energy density can be obtained.

  Examples of the material having at least one of silicon and tin include, for example, a simple substance, an alloy or a compound of silicon, a simple substance, an alloy or a compound of tin, or one or two or more phases thereof. Materials.

  Examples of the material having a simple substance of silicon include a material mainly having a simple substance of silicon. The negative electrode active material layer 22B containing such a material has, for example, a structure in which constituent elements other than silicon and oxygen are present between the silicon simple substance layers. The total content of silicon and oxygen in the anode active material layer 22B is preferably 50% by mass or more, and particularly preferably the content of silicon alone is 50% by mass or more. Examples of constituent elements other than silicon include titanium, chromium, manganese, iron, cobalt, nickel, copper, zinc, indium, silver, magnesium, aluminum, germanium, tin, bismuth, and antimony (Sb). . The negative electrode active material layer 22B containing a material mainly composed of a simple substance of silicon is formed, for example, by co-evaporation of silicon and other constituent elements.

Examples of silicon alloys include, among other constituent elements other than silicon, tin, nickel, copper, iron, cobalt, manganese, zinc, indium, silver, titanium, germanium, bismuth, antimony (Sb), and chromium. The thing which has at least 1 sort (s) of metal element is mentioned. Examples of the silicon compound include those having non-metallic elements such as oxygen (O) or carbon (C) as constituent elements other than silicon, and those having the metal elements described for silicon alloys. It is done. Examples of silicon alloys or compounds include SiB ₄ , SiB ₆ , Mg ₂ Si, Ni ₂ Si, TiSi ₂ , MoSi ₂ , CoSi ₂ , NiSi ₂ , CaSi ₂ , CrSi ₂ , Cu ₅ Si, FeSi ₂ , MnSi. ₂ , NbSi ₂ , TaSi ₂ , VSi ₂ , WSi ₂ , ZnSi ₂ , SiC, Si ₃ N ₄ , Si ₂ N ₂ O, SiO _v (0 <v ≦ 2), or LiSiO.

As an alloy of tin, for example, as a constituent element other than tin, at least one of silicon, nickel, copper, iron, cobalt, manganese, zinc, indium, silver, titanium, germanium, bismuth, antimony and chromium The thing which has these metal elements is mentioned. Examples of the tin compound include those having non-metallic elements such as oxygen or carbon as constituent elements other than tin, and those having the metal elements described for the tin alloy. Examples of tin alloys or compounds include SnO _w (0 <w ≦ 2), SnSiO ₃ , LiSnO, or Mg ₂ Sn.

  In particular, the material having at least one of silicon and tin is preferably a material having, for example, tin as the first constituent element and, in addition thereto, the second and third constituent elements. The second constituent elements are cobalt, iron, magnesium, titanium, vanadium (V), chromium, manganese, nickel, copper, zinc, gallium, zirconium, niobium (Nb), molybdenum, silver, indium, cerium (Ce), It is at least one of hafnium, tantalum (Ta), tungsten (W), bismuth and silicon. The third constituent element is at least one of boron, carbon, aluminum, and phosphorus (P). This is because having the second and third constituent elements improves the cycle characteristics.

  Among these, tin, cobalt, and carbon are included as constituent elements, the carbon content is 9.9 mass% to 29.7 mass%, and the ratio of cobalt to the total of tin and cobalt (Co / (Sn + Co)) is 30. An SnCoC-containing material having a mass% of 70% by mass or less is preferable. This is because a high energy density can be obtained in such a composition range.

  This SnCoC-containing material may further contain other constituent elements as necessary. As other constituent elements, for example, silicon, iron, nickel, chromium, indium, niobium, germanium, titanium, molybdenum, aluminum, phosphorus, gallium, bismuth, and the like are preferable, and two or more of them may be used. This is because a higher effect can be obtained.

  The SnCoC-containing material includes a phase having tin, cobalt, and carbon, and the phase preferably has a low crystalline or amorphous structure. This phase is a reaction phase capable of reacting with lithium ions, and the half-value width of the diffraction peak obtained by X-ray diffraction of the phase is CuKα ray as the specific X-ray and the insertion speed is 1 ° / min. In this case, the diffraction angle 2θ is preferably 1.0 ° or more. This is because lithium ions are occluded and released more smoothly, and the reactivity with the electrolyte is reduced.

  Whether a diffraction peak obtained by X-ray diffraction corresponds to a reaction phase capable of reacting with lithium ions can be easily determined by comparing X-ray diffraction charts before and after electrochemical reaction with lithium ions. Can be judged. For example, if the position of the diffraction peak changes before and after the electrochemical reaction with lithium ions, it corresponds to a reaction phase capable of reacting with lithium ions. In this case, for example, a diffraction peak of a low crystalline or amorphous reaction phase is observed between 2θ = 20 ° and 50 °. This low crystalline or amorphous reaction phase has, for example, each of the above-described constituent elements, and is considered to be mainly low-crystallized or amorphous due to carbon.

  Note that the SnCoC-containing material may contain a phase having a simple substance or a part of each constituent element in addition to the low crystalline or amorphous phase.

  In particular, in the SnCoC-containing material, it is preferable that at least a part of carbon that is a constituent element is bonded to a metal element or a metalloid element that is another constituent element. This is because aggregation or crystallization of tin or the like is suppressed.

  As a measuring method for examining the bonding state of elements, for example, XPS can be mentioned. This XPS irradiates a sample surface with soft X-rays (Al-Kα ray or Mg-Kα ray is used in a commercially available apparatus), and measures the kinetic energy of photoelectrons jumping out of the sample surface. In this method, the composition and bonding state of elements in the region of a few nanometers are examined.

  The binding energy of the core orbital electrons of the element changes in a first approximation in correlation with the charge density on the element. For example, when the charge density of a carbon element is reduced due to an interaction with an element present in the vicinity thereof, outer electrons such as 2p electrons are reduced, so that the 1s electron of the carbon element is strongly bound from the shell. You will receive power. That is, the binding energy increases as the charge density of the element decreases. In XPS, when the binding energy increases, the peak shifts to a high energy region.

  In XPS, when energy calibration is performed so that the peak of 4f orbit of gold atom (Au4f) is obtained at 84.0 eV, the peak of 1s orbit of carbon (C1s) appears at 284.5 eV in the case of graphite, If it is surface contaminated carbon, it appears at 284.8 eV. In contrast, when the charge density of the carbon element is high, for example, when it is bonded to an element more positive than carbon, the C1s peak appears in a region lower than 284.5 eV. That is, when at least a part of carbon contained in the SnCoC-containing material is bonded to another constituent element such as a metal element or a metalloid element, the peak of the synthetic wave of C1s obtained for the SnCoC-containing material is 284. Appears in the region lower than 5 eV.

  When the sample surface is covered with surface-contaminated carbon, for example, it is preferable to lightly sputter the sample surface using an argon ion gun attached to the XPS apparatus. For example, when the SnCoC-containing material to be measured is present in the negative electrode of the secondary battery, the secondary battery is disassembled and the negative electrode is taken out, and then washed with a volatile solvent such as dimethyl carbonate. This is for removing a low-volatile solvent and an electrolyte salt present on the surface of the negative electrode. These sampling operations are desirably performed in an inert atmosphere.

  In XPS measurement, for example, the peak of C1s is used to correct the energy axis of the spectrum. Usually, since surface-contaminated carbon is present on the surface of the material, the C1s peak of the surface-contaminated carbon is set to 284.8 eV, which is used as an energy standard. In the XPS measurement, the waveform of the C1s peak is obtained as a form including the surface contamination carbon peak and the carbon peak in the SnCoC-containing material. For example, by analyzing using commercially available software, The surface contamination carbon peak and the carbon peak in the SnCoC-containing material are separated. In the waveform analysis, the position of the main peak existing on the lowest bound energy side is used as the energy reference (284.8 eV).

  This SnCoC-containing material can be formed, for example, by solidifying a mixture obtained by mixing raw materials of each constituent element in an electric furnace, a high-frequency induction furnace, an arc melting furnace, or the like. Also, various atomization methods such as gas atomization or water atomization, various roll methods, methods using mechanochemical reactions such as mechanical alloying methods or mechanical milling methods, etc. may be used, and among these, mechanochemical reactions are used. The method is preferred. This is because the SnCoC-containing material tends to have a low crystalline or amorphous structure. In the method using the mechanochemical reaction, for example, a production apparatus such as a planetary ball mill apparatus or an attritor can be used.

  The raw material may be a mixture of individual constituent elements, but an alloy is preferably used for some constituent elements other than carbon. This is because, by adding carbon to the alloy and synthesizing by a method using a mechanical alloying method, it is easy to obtain a low crystallization or amorphous structure and the reaction time is shortened. The raw material may be in the form of powder or a block.

  In addition, as a material having at least one of silicon and tin, in addition to the above-described SnCoC-containing material, a SnCoFeC-containing material having tin, cobalt, iron, and carbon as constituent elements is also preferable. The composition of the SnCoFeC-containing material can be arbitrarily set. For example, as a composition when the iron content is set to be small, the carbon content is 9.9 mass% or more and 29.7 mass% or less, and the iron content is 0.3 mass% or more and 5.9 mass%. % Or less, and the ratio of cobalt to the total of tin and cobalt (Co / (Sn + Co)) is preferably 30% by mass or more and 70% by mass or less. In addition, for example, as a composition when the content of iron is set to be large, the content of carbon is 11.9 mass% or more and 29.7 mass% or less, and cobalt and iron with respect to the total of tin, cobalt, and iron The total ratio of (Co + Fe) / (Sn + Co + Fe)) is 26.4 mass% to 48.5 mass%, and the ratio of cobalt to the total of cobalt and iron (Co / (Co + Fe)) is 9.9 mass% It is preferable that it is 79.5 mass% or less. This is because a high energy density can be obtained in such a composition range. The crystallinity of the SnCoFeC-containing material, the method for measuring the bonding state of elements, the formation method, and the like are the same as those described for the SnCoC-containing material.

  Moreover, as a negative electrode material, a carbon material is mentioned, for example. Examples of the carbon material include graphitizable carbon, non-graphitizable carbon having a (002) plane spacing of 0.37 nm or more, or graphite having a (002) plane spacing of 0.34 nm or less. is there. More specifically, there are pyrolytic carbons, cokes, graphites, glassy carbon fibers, fired organic polymer compounds, carbon fibers, activated carbon, carbon blacks, and the like. Of these, the cokes include pitch coke, needle coke, petroleum coke, and the like. The graphites include natural graphite or artificial graphite such as spherical carbon fine particles (MCMB). The organic polymer compound fired body is obtained by carbonizing a phenol resin or a furan resin at a suitable temperature. A carbon material is preferable because a change in crystal structure associated with insertion and extraction of lithium ions is very small, so that a high energy density can be obtained and it can also function as a conductive agent. The shape of the carbon material may be any of a fibrous shape, a spherical shape, a granular shape, or a scale shape.

  Furthermore, examples of the negative electrode material include a metal oxide or a polymer compound that can occlude and release lithium ions. Examples of the metal oxide include iron oxide, ruthenium oxide, and molybdenum oxide. Examples of the polymer compound include polyacetylene, polyaniline, and polypyrrole.

  Of course, the negative electrode material may be other than the above. Further, two or more kinds of the series of negative electrode materials may be mixed in any combination.

  The negative electrode active material layer 22B is formed by, for example, a vapor phase method, a liquid phase method, a thermal spray method, a coating method, a firing method, or two or more methods thereof. In this case, the anode current collector 22A and the anode active material layer 22B are preferably alloyed at least at a part of the interface. Specifically, the constituent element of the negative electrode current collector 22A may be diffused into the negative electrode active material layer 22B at the interface between them, or the constituent element of the negative electrode active material layer 22B is diffused into the negative electrode current collector 22A. These constituent elements may be diffused with each other. This is because breakage due to expansion and contraction of the negative electrode active material layer 22B during charging and discharging is suppressed, and electron conductivity between the negative electrode current collector 22A and the negative electrode active material layer 22B is improved.

  As the vapor phase method, for example, physical deposition method or chemical deposition method, specifically, vacuum deposition method, sputtering method, ion plating method, laser ablation method, thermal chemical vapor deposition (CVD) method or Examples include plasma chemical vapor deposition. As the liquid phase method, a known method such as electrolytic plating or electroless plating can be used. The application method is, for example, a method in which a particulate negative electrode active material is mixed with a binder and then dispersed in a solvent and applied. The baking method is, for example, a method in which a heat treatment is performed at a temperature higher than the melting point of a binder or the like after coating using a coating method. A known method can also be used for the firing method, for example, an atmospheric firing method, a reactive firing method, a hot press firing method, or the like.

  The negative electrode active material included in the negative electrode active material layer 22B is, for example, in the form of a plurality of particles. That is, the negative electrode active material layer 22B has a plurality of particulate negative electrode active materials (hereinafter simply referred to as “negative electrode active material particles”). It is formed by. However, the negative electrode active material particles may be formed by a method other than the vapor phase method.

  When the negative electrode active material particles are formed by a deposition method such as a gas phase method, the negative electrode active material particles may have a single-layer structure formed by a single deposition process, You may have the multilayered structure formed of the deposition process. However, when the negative electrode active material particles are formed by using a vapor deposition method with high heat during deposition, the negative electrode active material particles preferably have a multilayer structure. The negative electrode current collector 2 is exposed to high heat by dividing the negative electrode material deposition process into a plurality of times (the negative electrode material is successively formed and deposited in a thin film) as compared with the case where the deposition process is performed once. This is because it takes less time to heat, and is less susceptible to thermal damage.

  For example, the negative electrode active material particles preferably grow from the surface of the negative electrode current collector 22A in the thickness direction of the negative electrode active material layer 22B and are connected to the negative electrode current collector 22A at the root. This is because the expansion and contraction of the negative electrode active material layer 22B are suppressed during charging and discharging. In this case, the negative electrode active material particles are formed by a vapor phase method or the like, and as described above, it is preferable that the negative electrode active material particles are alloyed at least at a part of the interface with the negative electrode current collector 22A. Specifically, the constituent element of the negative electrode current collector 22A may be diffused into the negative electrode active material particles at the interface between them, or the constituent element of the negative electrode active material particles may be diffused into the negative electrode current collector 22A. Alternatively, both constituent elements may be diffused with each other.

  In particular, the negative electrode active material layer 22B has an oxide-containing film that covers the surface of the negative electrode active material particles (a region that will be in contact with the electrolyte if no oxide-containing film is provided), if necessary. It is preferable. This is because the oxide-containing film functions as a protective film, so that the chemical stability of the negative electrode 22 is improved, and the decomposition reaction of the electrolyte is suppressed during charging and discharging. Note that the oxide-containing film may cover the entire surface of the negative electrode active material particles, or may cover only a part, and among them, it is preferable to cover the whole. This is because the decomposition reaction of the electrolyte is further suppressed.

  The oxide-containing film includes, for example, at least one of a silicon oxide, a germanium oxide, and a tin oxide, and preferably includes a silicon oxide. This is because the entire surface of the negative electrode active material particles can be easily covered and an excellent protective function can be obtained. Of course, the oxide-containing film may contain oxides other than the above-described silicon oxide and the like.

  The oxide-containing film is formed by, for example, a gas phase method or a liquid phase method, and among these, it is preferable that the oxide-containing film is formed by a liquid phase method. This is because the surface of the negative electrode active material particles can be easily covered over a wide range. Examples of the liquid phase method include a liquid phase precipitation method, a sol-gel method, a coating method, or a dip coating method. Among these, the liquid phase precipitation method, the sol-gel method, or the dip coating method is preferable, and the liquid phase precipitation method is more preferable. This is because a higher effect can be obtained. Note that the oxide-containing film may be formed by a single method among the above-described series of forming methods, or may be formed by two or more methods.

  Moreover, it is preferable that the negative electrode active material layer 22B has a metal material that does not alloy with lithium ions in the void (gap) in the negative electrode active material layer 22B as necessary. This is because a plurality of negative electrode active material particles are bound via the metal material, and expansion and contraction of the negative electrode active material layer 22B are suppressed by the presence of the metal material in the gaps described above.

  This metal material has, for example, a metal element that does not alloy with lithium ions as a constituent element. Examples of such a metal element include at least one of iron, cobalt, nickel, zinc, and copper. This is because the metal material can easily enter the gaps and has excellent binding properties. Of course, the metal material may have other metal elements other than the above-described iron or the like. However, the “metal material” mentioned here is a wide concept including not only a simple substance but also an alloy and a metal compound.

  Further, the metal material is formed by, for example, a gas phase method or a liquid phase method, and among these, it is preferable that the metal material is formed by a liquid phase method. This is because the metal material easily enters the gap in the negative electrode active material layer 22B. Examples of the liquid phase method include an electrolytic plating method and an electroless plating method, among which the electrolytic plating method is preferable. This is because the metal material is more likely to enter the gaps and the formation time thereof can be shortened. Note that the metal material may be formed by a single method among the above-described series of forming methods, or may be formed by two or more methods.

  Furthermore, the metal material preferably has crystallinity. This is because the resistance of the entire negative electrode 22 is reduced and lithium ions are more likely to be occluded and released in the negative electrode 22 as compared with a case where the crystal does not have crystallinity (amorphous). In addition, since lithium ions are uniformly occluded and released during initial charging, local stress is unlikely to be applied to the negative electrode 22, so that generation of wrinkles is suppressed.

  Note that the negative electrode active material layer 22B may include only one of the oxide-containing film or the metal material described above, or may include both. However, in order to obtain a higher effect, it is preferable to have both. In addition, in the case of having only one of them, it is preferable to have an oxide-containing film in order to obtain a higher effect. Note that in the case of having both the oxide-containing film and the metal material, whichever may be formed first, in order to obtain a higher effect, it is preferable to form the oxide-containing film first.

  Here, a detailed configuration of the negative electrode will be described with reference to FIGS.

  First, the case where the negative electrode active material layer 22B has an oxide-containing film together with a plurality of negative electrode active material particles will be described. FIG. 3 schematically shows a cross-sectional configuration of the negative electrode of the present invention, and FIG. 4 schematically shows a cross-sectional configuration of the negative electrode of the reference example. 3 and 4 show the case where the negative electrode active material particles have a single layer structure.

  In the negative electrode of the present invention, as shown in FIG. 3, for example, when a negative electrode material is deposited on the negative electrode current collector 22A using a vapor phase method such as a vapor deposition method, a plurality of the negative electrode current collectors 22A are formed on the negative electrode current collector 22A. Negative electrode active material particles 221 are formed. In this case, when the surface of the negative electrode current collector 22A is roughened and a plurality of protrusions (for example, fine particles formed by electrolytic treatment) are present on the surface, the negative electrode active material particles 221 are arranged together with the protrusions described above. In order to grow in the thickness direction, a plurality of negative electrode active material particles 221 are arranged on the negative electrode current collector 22A and connected to the surface of the negative electrode current collector 22A at the root. After that, for example, when the oxide-containing film 222 is formed on the surface of the negative electrode active material particle 221 using a liquid phase method such as a liquid phase precipitation method, the oxide-containing film 222 is formed on the surface of the negative electrode active material particle 221. Is covered almost entirely, and in particular, covers a wide range from the top of the negative electrode active material particles 221 to the root. This wide covering state by the oxide-containing film 222 is a characteristic seen when the oxide-containing film 222 is formed by a liquid phase method. That is, when the oxide-containing film 222 is formed by using the liquid phase method, the covering action extends not only to the top of the negative electrode active material particles 221 but also to the root, and thus the base is covered with the oxide-containing film 222. .

  On the other hand, in the negative electrode of the reference example, as shown in FIG. 4, for example, after a plurality of negative electrode active material particles 221 are formed using the vapor phase method, the oxide is similarly formed using the vapor phase method. When the containing film 223 is formed, the oxide-containing film 223 covers only the tops of the negative electrode active material particles 221. This narrow covering state by the oxide-containing film 223 is a characteristic seen when the oxide-containing film 223 is formed by a vapor phase method. That is, when the oxide-containing film 223 is formed using the vapor phase method, the covering action does not reach the root of the negative electrode active material particle 221, so that the base is not covered by the oxide-containing film 223. .

  Although FIG. 3 illustrates the case where the negative electrode active material layer 22B is formed using a vapor phase method, the negative electrode active material layer 22B is formed using another method such as a coating method or a sintering method. Similarly, in some cases, the oxide-containing film 222 is formed so as to cover almost the entire surface of the plurality of negative electrode active material particles 221.

  Next, the case where the negative electrode active material layer 22B includes a metal material that does not alloy with lithium ions together with a plurality of negative electrode active material particles will be described. FIG. 5 shows an enlarged cross-sectional configuration of the negative electrode, where (A) is a scanning electron microscope (SEM) photograph (secondary electron image), and (B) is an SEM image shown in (A). It is a schematic picture. FIG. 5 shows a case where a plurality of negative electrode active material particles have a multilayer structure in the particles.

  When the negative electrode active material particles 221 have a multilayer structure, a plurality of gaps 224 are generated in the negative electrode active material layer 22B due to the arrangement structure, multilayer structure, and surface structure of the plurality of negative electrode active material particles 221. . The gap 224 mainly includes two types of gaps 224A and 224B classified according to the cause of occurrence. The gap 224 </ b> A is generated between adjacent negative electrode active material particles 221, and the gap 224 </ b> B is generated between layers in the negative electrode active material particles 221.

  Note that a void 225 may be formed on the exposed surface (outermost surface) of the negative electrode active material particles 221. The void 225 is generated between the protrusions as a whisker-like fine protrusion (not shown) is formed on the surface of the negative electrode active material particle 221. The void 225 may be generated over the entire exposed surface of the negative electrode active material particles 221 or may be generated only in part. However, since the above-described whisker-like protrusions are generated on the surface every time the negative electrode material is deposited, the voids 225 may be generated not only between the exposed surfaces of the negative electrode active material particles 221 but also between the layers.

  FIG. 6 shows another cross-sectional configuration of the negative electrode and corresponds to FIG. The negative electrode active material layer 22B has a metal material 226 that does not alloy with lithium ions in the gaps 224A and 224B. In this case, the metal material 226 may be provided in only one of the gaps 224A and 224B, but it is preferable that the metal material 226 is provided in both of them. This is because a higher effect can be obtained.

  The metal material 226 enters the gap 224A between the adjacent negative electrode active material particles 221. Specifically, when the negative electrode active material particles 221 are formed by a vapor phase method or the like, as described above, the negative electrode active material particles 221 grow for each protrusion existing on the surface of the negative electrode current collector 22A. A gap 224 </ b> A is generated between the adjacent negative electrode active material particles 221. Since the gap 224A causes a decrease in the binding property of the negative electrode active material layer 22B, a metal material 226 is embedded in the gap 224A in order to improve the binding property. In this case, it is sufficient that a part of the gap 224A is buried, but it is preferable that the amount of filling is large. This is because the binding property of the negative electrode active material layer 22B is further improved. The embedding amount of the metal material 226 is preferably 20% or more, more preferably 40% or more, and further preferably 80% or more.

  In addition, the metal material 226 enters the gap 224 </ b> B in the negative electrode active material particles 221. Specifically, when the negative electrode active material particles 221 have a multilayer structure, a gap 224B is generated between the layers. The gap 224B, like the gap 224A, causes a decrease in the binding property of the negative electrode active material layer 22B. Therefore, in order to improve the binding property, the metal material 226 is embedded in the gap 224B. ing. In this case, it is sufficient that a part of the gap 224B is buried, but it is preferable that the amount of filling is large. This is because the binding property of the negative electrode active material layer 22B is further improved.

  Note that the negative electrode active material layer 22B is formed in order to prevent negative whisker-shaped protrusions (not shown) generated on the exposed surface (outermost surface) of the negative electrode active material particles 221 from adversely affecting the performance of the negative electrode. A metal material 226 may be provided in the gap 225. Specifically, when the negative electrode active material particles 221 are formed by a vapor phase method or the like, fine whisker-like protrusions are formed on the surface thereof, and voids 225 are generated between the protrusions. The voids 225 increase the surface area of the negative electrode active material particles 221 and also increase the amount of irreversible film formed on the surfaces thereof, which may cause a reduction in the progress of the charge / discharge reaction. . Therefore, the metal material 226 is embedded in the gap 225 in order to suppress a decrease in the progress of the charge / discharge reaction. In this case, it is sufficient that a part of the gap 225 is buried, but the larger the amount of filling, the better. This is because the progress of the charge / discharge reaction can be further suppressed. In FIG. 6, the fact that the metal material 226 is scattered on the exposed surface of the negative electrode active material particles 221 indicates that the above-described fine protrusions are present at the scattered points. Of course, the metal material 226 does not necessarily have to be scattered on the surface of the negative electrode active material particle 221, and may cover the entire surface.

  In particular, the metal material 226 that has entered the gap 224B also functions to fill the gap 225 in each layer. Specifically, when the negative electrode material is deposited a plurality of times, the fine protrusions described above are generated at every deposition. For this reason, the metal material 226 is not only embedded in the gap 224B in each layer, but also embedded in the gap 225 in each layer.

  5 and 6, the negative electrode active material particles 221 have a multilayer structure, and the case where both the gaps 224A and 224B exist in the negative electrode active material layer 22B has been described. 22B has a metal material 226 in the gaps 224A and 224B. On the other hand, when the negative electrode active material particle 221 has a single layer structure and only the gap 224A exists in the negative electrode active material layer 22B, the negative electrode active material layer 22B has the metal material 226 only in the gap 224A. Will have. Of course, since the gap 225 is generated in both cases, the gap 225 has the metal material 226 in either case.

  The negative electrode coating 22C is formed on the negative electrode active material layer 22B after the negative electrode active material layer 22B is formed on the negative electrode current collector 22A. As described above, the negative electrode coating 22C includes at least one of fluororesins represented by the formulas (1) and (2). This is because the chemical stability of the negative electrode 22 is improved. Thereby, at the time of charging / discharging, lithium ions are efficiently occluded and released in the negative electrode 22, and the decomposition reaction of the electrolyte is suppressed, so that the cycle characteristics are improved.

  The negative electrode coating 22C may be provided so as to cover the entire surface of the negative electrode active material layer 22B, or may be provided so as to cover a part of the surface thereof. In this case, a part of the negative electrode film 22C may enter the negative electrode active material layer 22B.

  Examples of the method for forming the anode coating 22C include a liquid phase method such as a coating method, a dipping method, a dip coating method, or a spray method, and a vapor phase method such as a vapor deposition method, a sputtering method, or a CVD method. About these methods, you may use independently and may use 2 or more types of methods together. Among these, for example, in the liquid phase method, it is preferable to form the anode coating 22C using a solution containing a fluororesin. Specifically, for example, in the dipping method, the negative electrode active material layer 22B is dipped in a solution containing a fluororesin, and then pulled up and dried. In the coating method, a solution containing a fluororesin is applied to the surface of the negative electrode active material layer 22B and then dried. This is because a good negative electrode film 22B having high chemical stability is easily formed. Examples of the solvent for dissolving the fluororesin include a highly polar solvent such as water as described above.

  The separator 23 separates the positive electrode 21 and the negative electrode 22 and allows lithium ions to pass through while preventing a short circuit of current due to contact between the two electrodes. The separator 23 is made of, for example, a porous film made of a synthetic resin such as polytetrafluoroethylene, polypropylene, or polyethylene, a porous film made of ceramic, or the like, and these two or more kinds of porous films are laminated. It may be what was done.

  The separator 23 is impregnated with an electrolytic solution that is a liquid electrolyte. This electrolytic solution contains a solvent and an electrolyte salt dissolved in the solvent.

  The solvent contains, for example, one or more nonaqueous solvents such as organic solvents. The series of solvents described below may be arbitrarily combined.

  Examples of the non-aqueous solvent include ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, methyl propyl carbonate, γ-butyrolactone, γ-valerolactone, 1,2-dimethoxyethane, tetrahydrofuran, 2 -Methyltetrahydrofuran, tetrahydropyran, 1,3-dioxolane, 4-methyl-1,3-dioxolane, 1,3-dioxane, 1,4-dioxane, methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, butyric acid Methyl, methyl isobutyrate, methyl trimethylacetate, ethyl trimethylacetate, acetonitrile, glutaronitrile, adiponitrile, methoxyacetonitrile, 3-methoxypropionitrile, N, N-dimethylformamide, N-methylpyrrolidinone, N-methyl Examples thereof include tiloxazolidinone, N, N′-dimethylimidazolidinone, nitromethane, nitroethane, sulfolane, trimethyl phosphate, and dimethyl sulfoxide. Among these, at least one of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate is preferable. In this case, a high viscosity (high dielectric constant) solvent such as ethylene carbonate or propylene carbonate (for example, a relative dielectric constant ε ≧ 30) and a low viscosity solvent such as dimethyl carbonate, ethyl methyl carbonate or diethyl carbonate (for example, viscosity ≦ 1 mPa · A combination with s) is more preferred. This is because the dissociation property of the electrolyte salt and the ion mobility are improved.

  In particular, the solvent contains at least one of a chain carbonate ester having a halogen represented by formula (3) as a constituent element and a cyclic carbonate ester having a halogen represented by formula (4) as a constituent element. Preferably it is. This is because a stable protective film is formed on the surface of the negative electrode 22 at the time of charge / discharge, so that the decomposition reaction of the electrolyte is suppressed.

（Ｒ１１〜Ｒ１６は水素基、ハロゲン基、アルキル基あるいはハロゲン化アルキル基であり、それらのうちの少なくとも１つはハロゲン基あるいはハロゲン化アルキル基である。）

(R11 to R16 are a hydrogen group, a halogen group, an alkyl group or a halogenated alkyl group, and at least one of them is a halogen group or a halogenated alkyl group.)

（Ｒ１７〜Ｒ２０は水素基、ハロゲン基、アルキル基あるいはハロゲン化アルキル基であり、それらのうちの少なくとも１つはハロゲン基あるいはハロゲン化アルキル基である。）

(R17 to R20 are a hydrogen group, a halogen group, an alkyl group or a halogenated alkyl group, and at least one of them is a halogen group or a halogenated alkyl group.)

  R11 to R16 in the formula (3) may be the same or different. That is, the types of R11 to R16 can be individually set within the above-described series of groups. The same applies to R17 to R20 in the formula (4).

  The kind of halogen is not particularly limited, but among them, fluorine, chlorine or bromine is preferable, and fluorine is more preferable. This is because a high effect can be obtained. This is because a higher effect can be obtained as compared with other halogens.

  However, the number of halogens is preferably two rather than one, and may be three or more. This is because the ability to form a protective film is increased and a stronger and more stable protective film is formed, so that the decomposition reaction of the electrolytic solution is further suppressed.

  Examples of the chain carbonic acid ester having a halogen represented by the formula (3) as a constituent element include fluoromethyl methyl carbonate, bis (fluoromethyl) carbonate, difluoromethyl methyl carbonate, and the like. These may be single and multiple types may be mixed.

  Examples of the cyclic carbonate having a halogen represented by the formula (4) as a constituent element include a series of compounds represented by the following formulas (4-1) to (4-21). That is, 4-fluoro-1,3-dioxolan-2-one, 4-chloro-1,3-dioxolan-2-one, 4,5-difluoro-1,3-dioxolan-2-one, tetrafluoro-1 , 3-Dioxolan-2-one, 4-chloro-5-fluoro-1,3-dioxolan-2-one, 4,5-dichloro-1,3-dioxolan-2-one, tetrachloro-1,3- Dioxolan-2-one, 4,5-bistrifluoromethyl-1,3-dioxolan-2-one, 4-trifluoromethyl-1,3-dioxolan-2-one, 4,5-difluoro-4,5- Dimethyl-1,3-dioxolan-2-one, 4,4-difluoro-5-methyl-1,3-dioxolan-2-one, 4-ethyl-5,5-difluoro-1,3-dioxolane-2- 4-fluoro-5-trifluoromethyl-1,3-dioxolan-2-one, 4-methyl-5-trifluoro-methyl-1,3-dioxolan-2-one, 4-fluoro-4,5 -Dimethyl-1,3-dioxolan-2-one, 5- (1,1-difluoroethyl) -4,4-difluoro-1,3-dioxolan-2-one, 4,5-dichloro-4,5- Dimethyl-1,3-dioxolan-2-one, 4-ethyl-5-fluoro-1,3-dioxolan-2-one, 4-ethyl-4,5-difluoro-1,3-dioxolan-2-one, 4-ethyl-4,5,5-trifluoro-1,3-dioxolan-2-one, 4-fluoro-4-methyl-1,3-dioxolan-2-one, and the like. These may be single and multiple types may be mixed.

  Of these, 4-fluoro-1,3-dioxolan-2-one or 4,5-difluoro-1,3-dioxolan-2-one is preferred, and 4,5-difluoro-1,3-dioxolan-2-one is preferred. More preferred. In particular, 4,5-difluoro-1,3-dioxolan-2-one is preferably a trans isomer rather than a cis isomer. This is because it is easily available and a high effect can be obtained.

  Moreover, it is preferable that the solvent contains at least 1 sort (s) of the cyclic carbonate which has an unsaturated carbon bond represented by Formula (5)-Formula (7). This is because a stable protective film is formed on the surface of the negative electrode 22 at the time of charge / discharge, so that the decomposition reaction of the electrolyte is suppressed.

（Ｒ２１およびＲ２２は水素基あるいはアルキル基である。）

(R21 and R22 are a hydrogen group or an alkyl group.)

（Ｒ２３〜Ｒ２６は水素基、アルキル基、ビニル基あるいはアリル基であり、それらのうちの少なくとも１つはビニル基あるいはアリル基である。）

(R23 to R26 are a hydrogen group, an alkyl group, a vinyl group, or an allyl group, and at least one of them is a vinyl group or an allyl group.)

（Ｒ２７はアルキレン基である。）

(R27 is an alkylene group.)

  The cyclic carbonate having an unsaturated carbon bond shown in Formula (5) is a vinylene carbonate compound. Examples of the vinylene carbonate compound include vinylene carbonate (1,3-dioxol-2-one), methyl vinylene carbonate (4-methyl-1,3-dioxol-2-one), and ethyl vinylene carbonate (4-ethyl). -1,3-dioxol-2-one), 4,5-dimethyl-1,3-dioxol-2-one, 4,5-diethyl-1,3-dioxol-2-one, 4-fluoro-1, Examples include 3-dioxol-2-one or 4-trifluoromethyl-1,3-dioxol-2-one, among which vinylene carbonate is preferable. This is because it is easily available and a high effect can be obtained.

  The cyclic carbonate having an unsaturated carbon bond shown in Formula (6) is a vinyl ethylene carbonate compound. Examples of the vinyl carbonate-based compound include vinyl ethylene carbonate (4-vinyl-1,3-dioxolan-2-one), 4-methyl-4-vinyl-1,3-dioxolan-2-one, and 4-ethyl. -4-vinyl-1,3-dioxolan-2-one, 4-n-propyl-4-vinyl-1,3-dioxolan-2-one, 5-methyl-4-vinyl-1,3-dioxolane-2 -One, 4,4-divinyl-1,3-dioxolan-2-one, 4,5-divinyl-1,3-dioxolan-2-one, and the like, among which vinyl ethylene carbonate is preferable. This is because it is easily available and a high effect can be obtained. Of course, as R23 to R26, all may be vinyl groups, all may be allyl groups, or vinyl groups and allyl groups may be mixed.

  The cyclic carbonate having an unsaturated carbon bond represented by the formula (7) is a methylene ethylene carbonate compound. Examples of the methylene ethylene carbonate compound include 4-methylene-1,3-dioxolan-2-one, 4,4-dimethyl-5-methylene-1,3-dioxolan-2-one, and 4,4-diethyl-5. -Methylene-1,3-dioxolan-2-one and the like. As this methylene ethylene carbonate compound, there may be one having two methylene groups in addition to one having one methylene group (compound shown in Formula (7)).

  The cyclic carbonate having an unsaturated carbon bond may be catechol carbonate (catechol carbonate) having a benzene ring in addition to those shown in the formulas (5) to (7).

  Moreover, it is preferable that the solvent contains sultone (cyclic sulfonate ester). This is because the chemical stability of the electrolyte is further improved. Examples of sultone include propane sultone and propene sultone. These may be single and multiple types may be mixed. The content of sultone in the solvent is, for example, 0.5% by weight or more and 5% by weight or less.

  Furthermore, it is preferable that the solvent contains an acid anhydride. This is because the chemical stability of the electrolytic solution is further improved. Examples of the acid anhydride include carboxylic anhydrides such as succinic anhydride, glutaric anhydride and maleic anhydride, disulfonic anhydrides such as ethanedisulfonic anhydride and propanedisulfonic anhydride, sulfobenzoic anhydride, anhydrous Examples thereof include anhydrides of carboxylic acid and sulfonic acid such as sulfopropionic acid or sulfobutyric anhydride. These may be used alone or in combination. The content of the acid anhydride in the solvent is, for example, 0.5% by weight or more and 5% by weight or less.

  The electrolyte salt contains, for example, any one or more of light metal salts such as lithium salts. The series of electrolyte salts described below may be arbitrarily combined.

Examples of the lithium salt include lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium tetraphenylborate (LiB (C ₆ H ₅ ) ₄ ), methane Lithium sulfonate (LiCH ₃ SO ₃ ), lithium trifluoromethanesulfonate (LiCF ₃ SO ₃ ), lithium tetrachloroaluminate (LiAlCl ₄ ), dilithium hexafluorosilicate (Li ₂ SiF ₆ ), lithium chloride (LiCl) ) Or lithium bromide (LiBr).

  Among these, at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, and lithium hexafluoroarsenate is preferable, and lithium hexafluorophosphate is more preferable. This is because a higher effect can be obtained because the internal resistance is lowered.

  In particular, the electrolyte salt preferably contains at least one of the compounds represented by the formulas (8) to (10). This is because a higher effect can be obtained. In addition, R31 and R33 of Formula (8) may be the same or different. The same applies to R41 to R43 in formula (9) and R51 and R52 in formula (10).

（Ｘ３１は長周期型周期表における１族元素あるいは２族元素、またはアルミニウムである。Ｍ３１は遷移金属元素、または長周期型周期表における１３族元素、１４族元素あるいは１５族元素である。Ｒ３１はハロゲン基である。Ｙ３１は−（Ｏ＝）Ｃ−Ｒ３２−Ｃ（＝Ｏ）−、−（Ｏ＝）Ｃ−Ｃ（Ｒ３３）₂ −あるいは−（Ｏ＝）Ｃ−Ｃ（＝Ｏ）−である。ただし、Ｒ３２はアルキレン基、ハロゲン化アルキレン基、アリーレン基あるいはハロゲン化アリーレン基である。Ｒ３３はアルキル基、ハロゲン化アルキル基、アリール基あるいはハロゲン化アリール基である。なお、ａ３は１〜４の整数であり、ｂ３は０、２あるいは４であり、ｃ３、ｄ３、ｍ３およびｎ３は１〜３の整数である。）

(X31 is a group 1 element or group 2 element in the long-period periodic table, or aluminum. M31 is a transition metal element, or a group 13 element, group 14 element, or group 15 element in the long-period periodic table. R31 Y31 is — (O═) C—R32—C (═O) —, — (O═) C—C (R33) ₂ — or — (O═) C—C (═O) Where R32 is an alkylene group, a halogenated alkylene group, an arylene group or a halogenated arylene group, R33 is an alkyl group, a halogenated alkyl group, an aryl group or a halogenated aryl group, and a3 is (It is an integer of 1 to 4, b3 is 0, 2 or 4, and c3, d3, m3 and n3 are integers of 1 to 3.)

（Ｘ４１は長周期型周期表における１族元素あるいは２族元素である。Ｍ４１は遷移金属元素、または長周期型周期表における１３族元素、１４族元素あるいは１５族元素である。Ｙ４１は−（Ｏ＝）Ｃ−（Ｃ（Ｒ４１）₂ ）_b4−Ｃ（＝Ｏ）−、−（Ｒ４３）₂ Ｃ−（Ｃ（Ｒ４２）₂ ）_c4−Ｃ（＝Ｏ）−、−（Ｒ４３）₂ Ｃ−（Ｃ（Ｒ４２）₂ ）_c4−Ｃ（Ｒ４３）₂ −、−（Ｒ４３）₂ Ｃ−（Ｃ（Ｒ４２）₂ ）_c4−Ｓ（＝Ｏ）₂ −、−（Ｏ＝）₂ Ｓ−（Ｃ（Ｒ４２）₂ ）_d4−Ｓ（＝Ｏ）₂ −あるいは−（Ｏ＝）Ｃ−（Ｃ（Ｒ４２）₂ ）_d4−Ｓ（＝Ｏ）₂ −である。ただし、Ｒ４１およびＲ４３は水素基、アルキル基、ハロゲン基あるいはハロゲン化アルキル基であり、それぞれのうちの少なくとも１つはハロゲン基あるいはハロゲン化アルキル基である。Ｒ４２は水素基、アルキル基、ハロゲン基あるいはハロゲン化アルキル基である。なお、ａ４、ｅ４およびｎ４は１あるいは２であり、ｂ４およびｄ４は１〜４の整数であり、ｃ４は０〜４の整数であり、ｆ４およびｍ４は１〜３の整数である。）

(X41 is a group 1 element or group 2 element in the long periodic table. M41 is a transition metal element, or a group 13, element or group 15 element in the long period periodic table. Y41 is − ( O =) C- (C (R41 ) 2) b4 -C (= O) -, - (R43) 2 C- (C (R42) 2) c4 -C (= O) -, - (R43) 2 C -(C (R42) ₂ ) _c4 -C (R43) ₂ -,-(R43) ₂ C- (C (R42) ₂ ) _c4 -S (= O) ₂ -,-(O =) ₂ S- ( C (R42) ₂ ) _d4- S (= O) _2- or-(O =) C- (C (R42) ₂ ) _d4- S (= O) _2- where R41 and R43 are hydrogen groups. , An alkyl group, a halogen group or a halogenated alkyl group, at least one of each being a halogen group or a halogenated alkyl group. R42 is a hydrogen group, an alkyl group, a halogen group or a halogenated alkyl group, wherein a4, e4 and n4 are 1 or 2, b4 and d4 are integers of 1 to 4, and c4 Is an integer from 0 to 4, and f4 and m4 are integers from 1 to 3.)

（Ｘ５１は長周期型周期表における１族元素あるいは２族元素である。Ｍ５１は遷移金属元素、または長周期型周期表における１３族元素、１４族元素あるいは１５族元素である。Ｒｆはフッ素化アルキル基あるいはフッ素化アリール基であり、いずれの炭素数も１〜１０である。Ｙ５１は−（Ｏ＝）Ｃ−（Ｃ（Ｒ５１）₂ ）_d5−Ｃ（＝Ｏ）−、−（Ｒ５２）₂ Ｃ−（Ｃ（Ｒ５１）₂ ）_d5−Ｃ（＝Ｏ）−、−（Ｒ５２）₂ Ｃ−（Ｃ（Ｒ５１）₂ ）_d5−Ｃ（Ｒ５２）₂ −、−（Ｒ５２）₂ Ｃ−（Ｃ（Ｒ５１）₂ ）_d5−Ｓ（＝Ｏ）₂ −、−（Ｏ＝）₂ Ｓ−（Ｃ（Ｒ５１）₂ ）_e5−Ｓ（＝Ｏ）₂ −あるいは−（Ｏ＝）Ｃ−（Ｃ（Ｒ５１）₂ ）_e5−Ｓ（＝Ｏ）₂ −である。ただし、Ｒ５１は水素基、アルキル基、ハロゲン基あるいはハロゲン化アルキル基である。Ｒ５２は水素基、アルキル基、ハロゲン基あるいはハロゲン化アルキル基であり、そのうちの少なくとも１つはハロゲン基あるいはハロゲン化アルキル基である。なお、ａ５、ｆ５およびｎ５は１あるいは２であり、ｂ５、ｃ５およびｅ５は１〜４の整数であり、ｄ５は０〜４の整数であり、ｇ５およびｍ５は１〜３の整数である。）

(X51 is a group 1 element or group 2 element in the long-period periodic table. M51 is a transition metal element, or a group 13, element or group 15 element in the long-period periodic table. Rf is fluorinated. An alkyl group or a fluorinated aryl group, each having 1 to 10 carbon atoms Y51 is — (O═) C— (C (R51) ₂ ) _d5 —C (═O) —, — (R52); ₂ C- (C (R51) ₂ ) _d5 -C (= O)-,-(R52) ₂ C- (C (R51) ₂ ) _d5 -C (R52) ₂ -,-(R52) ₂ C- ( _{C (R51) 2) d5 -S} (= O) 2 -, - (O =) 2 S- (C (R51) 2) e5 -S (= O) 2 - or - (O =) C- (C _{(R51) 2) e5 -S (} = O) 2 -. is, however, R51 is a hydrogen group, an alkyl group, a halogen group, or a halogen Kaa R52 is a hydrogen group, an alkyl group, a halogen group or a halogenated alkyl group, at least one of which is a halogen group or a halogenated alkyl group, wherein a5, f5 and n5 are 1 or 2; B5, c5 and e5 are integers of 1 to 4, d5 is an integer of 0 to 4, and g5 and m5 are integers of 1 to 3.)

  Group 1 elements are hydrogen, lithium, sodium, potassium, rubidium, cesium, and francium. Group 2 elements are beryllium, magnesium, calcium, strontium, barium and radium. Group 13 elements are boron, aluminum, gallium, indium and thallium. Group 14 elements are carbon, silicon, germanium, tin and lead. Group 15 elements are nitrogen, phosphorus, arsenic, antimony and bismuth.

  Examples of the compound represented by formula (8) include compounds represented by formula (8-1) to formula (8-6). Examples of the compound represented by formula (9) include compounds represented by formulas (9-1) to (9-8). Examples of the compound represented by the formula (10) include a compound represented by the formula (10-1). Needless to say, the compound is not limited to the above-described compound as long as the compound has a structure represented by Formula (8) to Formula (10).

  Moreover, it is preferable that electrolyte salt contains at least 1 sort (s) of the compounds represented by Formula (11)-Formula (13). This is because a higher effect can be obtained. In addition, m and n in Formula (11) may be the same or different. The same applies to p, q and r in the formula (13).

（ｍおよびｎは１以上の整数である。）

(M and n are integers of 1 or more.)

（Ｒ６１は炭素数が２以上４以下の直鎖状あるいは分岐状のパーフルオロアルキレン基である。）

(R61 is a linear or branched perfluoroalkylene group having 2 to 4 carbon atoms.)

（ｐ、ｑおよびｒは１以上の整数である。）

(P, q and r are integers of 1 or more.)

Examples of the chain compound represented by the formula (11) include bis (trifluoromethanesulfonyl) imide lithium (LiN (CF ₃ SO ₂ ) ₂ ), bis (pentafluoroethanesulfonyl) imide lithium (LiN (C ₂ F) ₅ SO ₂ ) ₂ ), (trifluoromethanesulfonyl) (pentafluoroethanesulfonyl) imide lithium (LiN (CF ₃ SO ₂ ) (C ₂ F ₅ SO ₂ )), (trifluoromethanesulfonyl) (heptafluoropropanesulfonyl) imide Lithium (LiN (CF ₃ SO ₂ ) (C ₃ F ₇ SO ₂ )) or (trifluoromethanesulfonyl) (nonafluorobutanesulfonyl) imidolithium (LiN (CF ₃ SO ₂ ) (C ₄ F ₉ SO ₂ )) Etc. These may be single and multiple types may be mixed.

  Examples of the cyclic compound represented by Formula (12) include a series of compounds represented by Formula (12-1) to Formula (12-4). That is, 1,2-perfluoroethane disulfonylimide lithium, 1,3-perfluoropropane disulfonylimide lithium, 1,3-perfluorobutane disulfonylimide lithium, or 1,4-perfluorobutane disulfonylimide lithium Etc. These may be single and multiple types may be mixed.

Examples of the chain compound represented by the formula (13) include lithium tris (trifluoromethanesulfonyl) methide (LiC (CF ₃ SO ₂ ) ₃ ).

  The content of the electrolyte salt is preferably 0.3 mol / kg or more and 3.0 mol / kg or less with respect to the solvent. This is because, outside this range, the ion conductivity may be extremely lowered.

  In this secondary battery, at the time of charging, for example, lithium ions are released from the positive electrode 21 and inserted in the negative electrode 22 through the electrolytic solution impregnated in the separator 23. On the other hand, at the time of discharging, for example, lithium ions are released from the negative electrode 22 and inserted in the positive electrode 21 through the electrolytic solution impregnated in the separator 23.

  This secondary battery is manufactured by the following procedure, for example.

  First, the positive electrode 21 is produced. First, a positive electrode active material, a positive electrode binder, and a positive electrode conductive agent are mixed to form a positive electrode mixture, and then dispersed in an organic solvent to obtain a paste-like positive electrode mixture slurry. Subsequently, the cathode mixture slurry is uniformly applied to both surfaces of the cathode current collector 21A using a doctor blade or a bar coater, and then the organic solvent is evaporated and dried to form the cathode active material layer 21B. Finally, the positive electrode active material layer 21B is compression-molded using a roll press or the like while being heated as necessary. In this case, compression molding may be repeated a plurality of times.

  Next, the negative electrode 22 is produced. First, after preparing a negative electrode current collector 22A made of electrolytic copper foil or the like, a plurality of negative electrode active materials are obtained by depositing a negative electrode material on both surfaces of the negative electrode current collector 22A using a vapor phase method such as a vapor deposition method. Form particles. Subsequently, as necessary, an oxide-containing film is formed using a liquid phase method such as a liquid phase deposition method, or a metal material is formed using a liquid phase method such as an electrolytic plating method, or both are formed. Thus, the negative electrode active material layer 22B is formed. Finally, the negative electrode current collector 22A on which the negative electrode active material layer 22B is formed is immersed in a solution containing a fluororesin, and then pulled up and dried, whereby the negative electrode coating 22C containing the fluororesin is converted into a negative electrode active material. Formed on layer 22B. When forming this negative electrode film 22C, the above-described solution may be applied to the surface of the negative electrode active material layer 22B and dried.

  The secondary battery is assembled as follows. First, the positive electrode lead 25 is attached to the positive electrode 21 by welding or the like, and the negative electrode lead 26 is attached to the negative electrode 22 by welding or the like. Subsequently, the positive electrode 21 and the negative electrode 22 are laminated and wound through the separator 23 to produce the wound electrode body 20. Subsequently, the center pin 24 is inserted into the winding center of the wound electrode body 20. Subsequently, the wound electrode body 20 is housed inside the battery can 11 while being sandwiched between the pair of insulating plates 12 and 13, and the distal end portion of the positive electrode lead 25 is welded to the safety valve mechanism 25, and the distal end portion of the negative electrode lead 26 is attached. Weld to battery can 11. Subsequently, an electrolyte is injected into the battery can 11 and impregnated in the separator 23. Finally, the battery lid 14, the safety valve mechanism 15, and the heat sensitive resistance element 16 are fixed to the open end of the battery can 11 by caulking through the gasket 37. Thereby, the secondary battery shown in FIGS. 1 to 6 is completed.

  According to the first secondary battery and the manufacturing method thereof, the negative electrode film 22C containing at least one of the fluororesins represented by the formulas (1) and (2) is provided on the negative electrode active material layer 22B. Therefore, the chemical stability of the negative electrode 22 is improved. Thereby, at the time of charging / discharging, lithium ions are easily occluded and released in the negative electrode 22 and the decomposition reaction of the electrolyte is suppressed. Therefore, cycle characteristics can be improved.

  In this case, if the negative electrode film 22C is formed using a solution containing the above-mentioned fluororesin, and more specifically, a simple process such as an immersion process or a coating process is used, special environmental conditions such as a reduced pressure environment can be obtained. Compared with the case where the required method is used, the favorable negative electrode film 22C can be produced stably and easily.

  In particular, when the negative electrode 22 includes a high-capacity material as the negative electrode active material, the cycle characteristics are improved, so that a higher effect can be obtained than when the negative electrode active material includes a carbon material or the like.

  Further, the electrolyte solvent may be at least one of a chain carbonate ester having a halogen represented by formula (3) as a constituent element and a cyclic carbonate ester having a halogen represented by formula (4) as a constituent element, or a formula If at least one of the cyclic carbonates having an unsaturated carbon bond represented by (5) to (7), sultone, or an acid anhydride is included, higher effects can be obtained.

  Further, the electrolyte salt of the electrolyte is at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, and lithium hexafluoroarsenate, and the formulas (8) to (10). If at least one of the compounds shown in FIG. 5 or at least one of the compounds shown in formula (11) to formula (13) is included, a higher effect can be obtained.

  In addition, although the case where the battery structure of the secondary battery is a cylindrical type has been described above, the battery structure is not necessarily limited thereto, and the battery structure may be other than the cylindrical type.

  FIG. 7 shows an exploded perspective configuration of another first secondary battery, and FIG. 8 shows an enlarged cross section taken along line VIII-VIII of the spirally wound electrode body 30 shown in FIG. Is an enlarged view of a part of the spirally wound electrode body 30 shown in FIG.

  The secondary battery is, for example, a lithium ion secondary battery, similar to the first secondary battery described above, and the positive electrode lead 31 and the negative electrode lead 32 are mainly attached to the inside of the film-shaped exterior member 40. The wound electrode body 30 is accommodated. The battery structure using the film-shaped exterior member 40 is called a laminate film type.

  For example, the positive electrode lead 31 and the negative electrode lead 32 are led out in the same direction from the inside of the exterior member 40 toward the outside. The positive electrode lead 31 is made of, for example, a metal material such as aluminum, and the negative electrode lead 32 is made of, for example, a metal material such as copper, nickel, or stainless steel. These metal materials are, for example, in a thin plate shape or a mesh shape.

  The exterior member 40 is made of, for example, an aluminum laminated film in which a nylon film, an aluminum foil, and a polyethylene film are bonded together in this order. The exterior member 40 has a structure in which, for example, outer edges of two rectangular aluminum laminate films are bonded to each other by fusion or an adhesive so that the polyethylene film faces the wound electrode body 30. ing.

  An adhesion film 41 is inserted between the exterior member 40 and the positive electrode lead 31 and the negative electrode lead 32 in order to prevent intrusion of outside air. The adhesion film 41 is made of a material having adhesion to the positive electrode lead 31 and the negative electrode lead 32. Examples of such a material include polyolefin resins such as polyethylene, polypropylene, modified polyethylene, and modified polypropylene.

  In addition, the exterior member 40 may be composed of a laminate film having another laminated structure instead of the above-described aluminum laminate film, or may be composed of a polymer film such as polypropylene or a metal film.

  The wound electrode body 30 is obtained by laminating and winding a positive electrode 33 and a negative electrode 34 via a separator 35 and an electrolyte layer 36, and an outermost peripheral portion thereof is protected by a protective tape 37, for example.

  In the positive electrode 33, for example, a positive electrode active material layer 33B is provided on both surfaces of a positive electrode current collector 33A having a pair of surfaces. In the negative electrode 34, for example, a negative electrode active material layer 34B and a negative electrode film 34C are provided in this order on both surfaces of a negative electrode current collector 34A having a pair of surfaces. The configurations of the positive electrode current collector 33A, the positive electrode active material layer 33B, the negative electrode current collector 34A, the negative electrode active material layer 34B, the negative electrode coating 34C, and the separator 35 are respectively the positive electrode current collector 21A in the first secondary battery described above, The configurations of the positive electrode active material layer 21B, the negative electrode current collector 22A, the negative electrode active material layer 22B, the negative electrode coating 22C, and the separator 23 are the same.

  The electrolyte layer 36 includes an electrolytic solution and a polymer compound that holds the electrolytic solution, and is a so-called gel electrolyte. A gel electrolyte is preferable because high ion conductivity (for example, 1 mS / cm or more at room temperature) is obtained and liquid leakage is prevented.

  Examples of the polymer compound include polyacrylonitrile, polyvinylidene fluoride, a copolymer of polyvinylidene fluoride and polyhexafluoropropylene, polytetrafluoroethylene, polyhexafluoropropylene, polyethylene oxide, polypropylene oxide, polyphosphazene, poly Examples thereof include siloxane, polyvinyl acetate, polyvinyl alcohol, polymethyl methacrylate, polyacrylic acid, polymethacrylic acid, styrene-butadiene rubber, nitrile-butadiene rubber, polystyrene, and polycarbonate. These may be single and multiple types may be mixed. Among these, polyacrylonitrile, polyvinylidene fluoride, polyhexafluoropropylene or polyethylene oxide is preferable. This is because it is electrochemically stable.

  The composition of the electrolytic solution is the same as the composition of the electrolytic solution in the first secondary battery described above. However, the solvent in this case is not only a liquid solvent but also a broad concept including those having ion conductivity capable of dissociating the electrolyte salt. Accordingly, when a polymer compound having ion conductivity is used, the polymer compound is also included in the solvent.

  Instead of the gel electrolyte layer 36 in which the electrolytic solution is held by the polymer compound, the electrolytic solution may be used as it is. In this case, the separator 35 is impregnated with the electrolytic solution.

  The secondary battery provided with the gel electrolyte layer 36 is manufactured by, for example, the following three methods.

  In the first manufacturing method, first, the positive electrode active material layer 33B is formed on both surfaces of the positive electrode current collector 33A by, for example, the same procedure as the positive electrode 21 and the negative electrode 22 in the first secondary battery described above, and the positive electrode 33, and a negative electrode active material layer 34B and a negative electrode coating 34C are formed in this order on both surfaces of the negative electrode current collector 34A to produce the negative electrode 34. Then, after preparing the precursor solution containing electrolyte solution, a high molecular compound, and a solvent, and apply | coating to the positive electrode 33 and the negative electrode 34, the gelled electrolyte layer 36 is formed by volatilizing a solvent. Subsequently, the positive electrode lead 31 is attached to the positive electrode current collector 33A by welding or the like, and the negative electrode lead 32 is attached to the negative electrode current collector 34A by welding or the like. Subsequently, the positive electrode 33 and the negative electrode 34 on which the electrolyte layer 36 is formed are laminated via the separator 35 and then wound in the longitudinal direction, and a protective tape 37 is adhered to the outermost peripheral portion thereof, whereby a wound electrode body is obtained. 30 is produced. Finally, for example, after the wound electrode body 30 is sandwiched between two film-shaped exterior members 40, the outer edge portions of the exterior member 40 are bonded to each other by heat fusion or the like, whereby the wound electrode body 30 is enclosed. At this time, the adhesion film 41 is inserted between the positive electrode lead 31 and the negative electrode lead 32 and the exterior member 40. Thereby, the laminate film type secondary battery shown in FIGS. 7 to 9 is completed.

  In the second manufacturing method, first, the positive electrode lead 31 is attached to the positive electrode 33 and the negative electrode lead 32 is attached to the negative electrode 34, and then the positive electrode 33 and the negative electrode 34 are stacked and wound via the separator 35. By adhering the protective tape 37 to the outermost peripheral portion, a wound body that is a precursor of the wound electrode body 30 is produced. Subsequently, after sandwiching the wound body between the two film-like exterior members 40, the remaining outer peripheral edge portion excluding the outer peripheral edge portion on one side is adhered by heat fusion or the like, thereby The wound body is accommodated in the exterior member 40. Subsequently, an electrolyte composition containing an electrolytic solution, a monomer that is a raw material of the polymer compound, a polymerization initiator, and other materials such as a polymerization inhibitor as necessary is prepared, and a bag-shaped exterior member After injecting into the inside of 40, the opening part of the exterior member 40 is sealed by heat sealing or the like. Finally, the gel electrolyte layer 36 is formed by thermally polymerizing the monomer to obtain a polymer compound. Thereby, the secondary battery is completed.

  In the third manufacturing method, a wound body is formed by forming a wound body in the same manner as in the second manufacturing method described above except that the separator 35 coated with the polymer compound on both sides is used first. 40 is housed inside. Examples of the polymer compound applied to the separator 35 include a polymer containing vinylidene fluoride as a component, that is, a homopolymer, a copolymer, or a multi-component copolymer. Specifically, polyvinylidene fluoride, binary copolymers containing vinylidene fluoride and hexafluoropropylene as components, and ternary copolymers containing vinylidene fluoride, hexafluoropropylene and chlorotrifluoroethylene as components. Such as coalescence. In addition, the high molecular compound may contain the other 1 type, or 2 or more types of high molecular compound with the polymer which uses the above-mentioned vinylidene fluoride as a component. Subsequently, after the electrolytic solution is prepared and injected into the exterior member 40, the opening of the exterior member 40 is sealed by heat fusion or the like. Finally, the exterior member 40 is heated while applying a load, and the separator 35 is brought into close contact with the positive electrode 33 and the negative electrode 34 through the polymer compound. As a result, the electrolytic solution is impregnated into the polymer compound, and the polymer compound is gelled, whereby the electrolyte layer 36 is formed. Thus, the secondary battery is completed.

  In the third manufacturing method, the swollenness of the secondary battery is suppressed as compared with the first manufacturing method. Further, in the third manufacturing method, compared to the second manufacturing method, there are hardly any monomers or polymerization initiators that are raw materials of the polymer compound remaining in the electrolyte layer 36, and the polymer compound forming step is further reduced. Since it is well controlled, sufficient adhesion can be obtained between the positive electrode 33, the negative electrode 34, the separator 35, and the electrolyte layer 36.

  According to the other first secondary battery and the manufacturing method thereof, the negative electrode film 34C containing at least one of the fluororesins represented by the formulas (1) and (2) on the negative electrode active material layer 34B. Therefore, the cycle characteristics can be improved by the same action as the first secondary battery described above. Other effects relating to the secondary battery and the manufacturing method thereof are the same as those described for the first secondary battery and the manufacturing method thereof.

(Secondary secondary battery)
FIG. 10 shows a configuration of the second secondary battery, and shows a cross-sectional configuration corresponding to FIG. This second secondary battery is, for example, the above-described second battery except that the positive electrode 21 contains at least one of the fluororesins shown in the formulas (1) and (2) instead of the negative electrode 22. 1 has the same configuration as the secondary battery.

  In the positive electrode 21, for example, a positive electrode active material layer 21B and a positive electrode coating 21C are provided in this order on both surfaces of a positive electrode current collector 21A. However, the positive electrode coating 21C may be provided only on one side of the positive electrode current collector 21A.

  The configuration of the positive electrode coating 21C is the same as the configuration of the negative electrode coating 22C in the first secondary battery described above. That is, the positive electrode coating 21C is formed on the positive electrode active material layer 21B after the positive electrode active material layer 21B is formed on the positive electrode current collector 21A, and is expressed by the following equations (1) and (2). It contains at least one of the indicated fluororesins. This is because the chemical stability of the positive electrode 21 is improved. Thereby, at the time of charging / discharging, lithium ions are efficiently occluded and released in the positive electrode 21, and the decomposition reaction of the electrolyte is suppressed.

  In the negative electrode 22, for example, a negative electrode active material layer 22B is provided on both surfaces of a negative electrode current collector 22A.

  In this secondary battery, the positive electrode active material layer 21B and the positive electrode coating 21C are formed in this order on both surfaces of the positive electrode current collector 21A to produce the positive electrode 21, and the negative electrode active material layer 22B is formed on both surfaces of the negative electrode current collector 22A. It is manufactured by the same procedure as that of the first secondary battery described above, except that the negative electrode 22 is formed.

  According to the second secondary battery and the manufacturing method thereof, the positive electrode coating 21C including at least one of the fluororesins represented by the formulas (1) and (2) is provided on the positive electrode active material layer 21B. Therefore, the chemical stability of the positive electrode 21 is improved. Therefore, cycle characteristics can be improved. Other effects relating to the secondary battery and the manufacturing method thereof are the same as those described for the first secondary battery and the manufacturing method thereof.

  In addition, although the case where the battery structure of the secondary battery is a cylindrical type has been described above, the battery structure is not necessarily limited thereto, and the battery structure may be other than the cylindrical type.

  FIG. 11 shows a configuration of another second secondary battery, and shows a cross-sectional configuration corresponding to FIG. This secondary battery is, for example, the other first described above except that the positive electrode 33 contains at least one of the fluororesins shown in the formulas (1) and (2) instead of the negative electrode 34. The secondary battery has the same configuration.

  The positive electrode 33 has the same configuration as the positive electrode 21 in the second secondary battery described above. For example, the positive electrode active material layer 33B and the positive electrode coating 33C are provided in this order on both surfaces of the positive electrode current collector 33A. Is. The negative electrode 22 has the same configuration as that of the negative electrode 22 in the second secondary battery described above. For example, the negative electrode active material layer 34B is provided on both surfaces of the negative electrode current collector 34A.

  In the secondary battery, a positive electrode active material layer 33B and a positive electrode coating 33C are formed in this order on both surfaces of the positive electrode current collector 33A to produce the positive electrode 33, and a negative electrode active material layer 34B is formed on both surfaces of the negative electrode current collector 34A. It is manufactured by the same procedure as that of the other first secondary battery described above except that the negative electrode 34 is formed.

  According to the other second secondary battery and the manufacturing method thereof, the positive electrode coating 33C containing at least one of the fluororesins represented by the formulas (1) and (2) on the positive electrode active material layer 33B. Therefore, the cycle characteristics can be improved by the same action as the above-described second secondary battery. Other effects relating to the secondary battery and the manufacturing method thereof are the same as those described for the second secondary battery and the manufacturing method thereof.

(Third secondary battery)
FIG. 12 shows a configuration of the third secondary battery, and shows a cross-sectional configuration corresponding to FIG. The third secondary battery is, for example, the first battery described above except that the electrolyte contains at least one of the fluororesins shown in the formulas (1) and (2) instead of the negative electrode 22. The secondary battery has the same configuration.

  The positive electrode 21 is, for example, one in which a positive electrode active material layer 21B is provided on both surfaces of a positive electrode current collector 21A. In the negative electrode 22, for example, a negative electrode active material layer 22B is provided on both surfaces of a negative electrode current collector 22A.

  The electrolyte contains at least one of the fluororesins represented by the formulas (1) and (2) together with the solvent and the electrolyte salt, and the fluororesin is dissolved or dispersed in the solvent.

  In this secondary battery, a positive electrode active material layer 21B is formed on both sides of a positive electrode current collector 21A to produce a positive electrode 21, and a negative electrode active material layer 22B is formed on both sides of a negative electrode current collector 22A to produce a negative electrode 22. At the same time, it is manufactured by the same procedure as that of the first secondary battery except that the electrolyte is prepared by dissolving the electrolyte salt in the solvent in which the fluororesin is dispersed.

  According to the third secondary battery and the manufacturing method thereof, the electrolyte contains at least one of the fluororesins represented by the formulas (1) and (2), and therefore the chemical stability of the electrolyte. Will improve. Thereby, the decomposition reaction of the electrolyte is suppressed during charging and discharging. Therefore, cycle characteristics can be improved. Other effects relating to the secondary battery and the manufacturing method thereof are the same as those described for the first secondary battery and the manufacturing method thereof.

  In addition, although the case where the battery structure of the secondary battery is a cylindrical type has been described above, the battery structure is not necessarily limited thereto, and the battery structure may be other than the cylindrical type.

  FIG. 13 shows a configuration of another third secondary battery, and shows a cross-sectional configuration corresponding to FIG. This secondary battery is described above, for example, except that the electrolyte (electrolyte layer 36) contains at least one of the fluororesins shown in formulas (1) and (2) instead of the negative electrode 34. It has the same configuration as the other first secondary batteries.

  The positive electrode 33 has the same configuration as that of the positive electrode 21 in the third secondary battery described above. For example, the positive electrode active material layer 33B is provided on both surfaces of the positive electrode current collector 33A. The negative electrode 34 has the same configuration as that of the negative electrode 22 in the above-described third secondary battery. For example, the negative electrode active material layer 34B is provided on both surfaces of the negative electrode current collector 34A.

  The electrolyte has the same composition as the electrolyte in the third secondary battery described above. For example, together with the solvent, the electrolyte salt, and the polymer compound, the electrolyte includes the fluororesin represented by the formula (1) and the formula (2). Contains at least one of them.

  In this secondary battery, the positive electrode active material layer 33B is formed on both surfaces of the positive electrode current collector 33A to produce the positive electrode 33, and the negative electrode active material layer 34B is formed on both surfaces of the negative electrode current collector 34A to produce the negative electrode 34. In addition, the battery is manufactured by the same procedure as that of the other first secondary battery described above except that an electrolyte is prepared by dissolving an electrolyte salt in a solvent in which a fluororesin is dispersed.

  According to the other third secondary battery and the manufacturing method thereof, the electrolyte contains at least one of the fluororesins represented by the formulas (1) and (2). The cycle characteristics can be improved by the same action as the secondary battery. Other effects relating to the secondary battery and the manufacturing method thereof are the same as those described for the third secondary battery and the manufacturing method thereof.

  In the first to third secondary batteries described above, any of the positive electrode 21, the negative electrode 22, or the electrolyte contains a fluororesin. However, the present invention is not limited to this, and the positive electrode 21, the negative electrode containing the fluororesin is not necessarily limited thereto. 22 or two or more electrolytes may be combined. The same applies to the other first to third secondary batteries described above.

  In the first to third secondary batteries described above, at least one of the positive electrode 21, the negative electrode 22, and the electrolyte contains a fluororesin. However, the present invention is not necessarily limited thereto, and other configurations other than these. The element may include a fluororesin. Examples of such other components include a separator 23 and the like. In the case where the separator 23 includes a fluororesin, for example, the fluororesin is introduced into the separator 23 as a coating similarly to the case where the positive electrode 21 and the negative electrode 22 include a fluororesin. Specifically, for example, a coating containing a fluororesin is provided on both surfaces of the separator 23. The same applies to the other first to third secondary batteries described above.

  Examples of the present invention will be described in detail.

(Experimental Examples 1-1 to 1-3)
The laminate film type secondary battery shown in FIGS. 7 and 8 was manufactured by the following procedure. In this case, a lithium ion secondary battery in which the capacity of the negative electrode 34 is expressed based on insertion and extraction of lithium ions was made.

First, the positive electrode 33 was produced. First, lithium carbonate (Li ₂ CO ₃ ) and cobalt carbonate (CoCO ₃ ) are mixed at a molar ratio of 0.5: 1, and then calcined in air at 900 ° C. for 5 hours to form a lithium cobalt composite. An oxide (LiCoO ₂ ) was obtained. Subsequently, after mixing 91 parts by mass of lithium cobalt composite oxide as a positive electrode active material, 6 parts by mass of graphite as a positive electrode conductive agent, and 3 parts by mass of polyvinylidene fluoride as a positive electrode binder, a positive electrode mixture was obtained. Dispersed in N-methyl-2-pyrrolidone to obtain a paste-like positive electrode mixture slurry. Finally, using a bar coater, the positive electrode mixture slurry was uniformly applied to both surfaces of the positive electrode current collector 33A made of a strip-shaped aluminum foil (thickness = 12 μm), dried, and then compressed using a roll press. The positive electrode active material layer 33B was formed by molding.

  Next, the negative electrode 34 was produced. First, by using an electron beam evaporation method using a deflection electron beam evaporation source, both surfaces of a negative electrode current collector 34A made of electrolytic copper foil (thickness = 18 μm, surface ten-point average roughness Rz = 3.5 μm) are formed. By depositing silicon as the negative electrode active material, a negative electrode active material layer 34B including a plurality of particulate negative electrode active materials was formed. In this case, 99% pure silicon was used as the evaporation source, the deposition rate was 10 nm / second, and the number of layers of the negative electrode active material was 1 (thickness = 7.5 μm). In addition, the oxygen content in the negative electrode active material was set to 3 atomic% by continuously introducing oxygen gas and, if necessary, water vapor into the chamber. Finally, the negative electrode current collector 34A on which the negative electrode active material layer 34B is formed is immersed in a 3% by weight aqueous solution in which a fluororesin is dispersed in water for 30 seconds, and then lifted and dried to obtain the fluorine. A negative electrode coating 34C containing a resin was formed on the negative electrode active material layer 34B. In this case, as the fluororesin, a compound represented by the formula (1-1) (number average molecular weight = 2000 or 1500) or a compound represented by the formula (2-1) was used.

  The synthesis procedure of each compound used as the fluororesin is as follows.

When synthesizing the compound represented by the formula (1-1) (number average molecular weight = 2000), first, 100 cm ³ of water is added to 20 g of perfluoropolyether (FLUOROLINK C) manufactured by Solvay Solexis Co., Ltd. While stirring, 0.74 g of lithium carbonate was added little by little. At this time, the perfluoropolyether was not dissolved in water at the beginning and was a non-uniform solution. However, as time passed, the perfluoropolyether was dissolved in water to form a uniform solution (aqueous solution). Subsequently, the aqueous solution was stirred overnight and then filtered to remove insolubles. Finally, the filtrate was concentrated to obtain 17 g of a compound in which a lithium carboxylate base was introduced into both ends of the perfluoropolyether.

  When synthesizing the compound represented by the formula (1-1) (number average molecular weight = 1500), first, 100 ml of water was added to 30 g of perfluoropolyether (FLUOROLINK C10) manufactured by Solvay Solexis Co., Ltd. While stirring, 1.5 g of lithium carbonate was added little by little. At this time, as in the case of using the above-mentioned FLUOROLINK C, a uniform solution (aqueous solution) was formed with time. Subsequently, the aqueous solution was stirred overnight and then filtered to remove insolubles. Finally, the filtrate was concentrated to obtain 24 g of a compound in which a lithium carboxylate base was introduced into both ends of the perfluoropolyether.

  When synthesizing the compound represented by the formula (2-1), first, 9.7 g of 2,5-bis (trifluoromethyl) -3,6-dioxaundecafluorononanoyl fluoride is added to 100 ml of water. Then, 0.72 g of lithium carbonate was added little by little while stirring. Subsequently, the aqueous solution was stirred overnight and then filtered to remove insolubles. Finally, the filtrate was concentrated to obtain 7.2 g of a compound in which a lithium carboxylate base was introduced at one end of perfluoropolyether.

Next, after mixing ethylene carbonate (EC) and diethyl carbonate (DEC) as a solvent, lithium hexafluorophosphate (LiPF ₆ ) is dissolved as an electrolyte salt to prepare an electrolytic solution that is a liquid electrolyte. did. In this case, the composition of the solvent (EC: DEC) was 50:50 by weight, and the content of the electrolyte salt was 1 mol / kg with respect to the solvent.

  Next, a secondary battery was assembled by using an electrolytic solution together with the positive electrode 33 and the negative electrode 34. First, the positive electrode lead 31 made of aluminum was welded to one end of the positive electrode current collector 33A, and the negative electrode lead 32 made of nickel was welded to one end of the negative electrode current collector 34A. Subsequently, the positive electrode 33, the separator 35 (thickness = 23 μm), the negative electrode 34, and the separator 35 are laminated in this order and then wound in the longitudinal direction, and then a protective tape 37 made of an adhesive tape is used. By fixing the winding end portion, a wound body that is a precursor of the wound electrode body 50 was formed. In this case, as the separator 35, a three-layer structure product in which a film mainly composed of porous polyethylene is sandwiched between films mainly composed of porous polypropylene. Subsequently, after the wound body was sandwiched between the exterior members 40, the wound body was accommodated inside the bag-shaped exterior member 40 by heat-sealing the outer edges except for one side. In this case, as the exterior member 40, three layers in which a nylon film (thickness = 30 μm), an aluminum foil (thickness = 40 μm), and an unstretched polypropylene film (thickness = 30 μm) are laminated from the outside. A laminate film having a structure (total thickness = 100 μm) was used. Subsequently, the wound electrode body 30 was manufactured by injecting an electrolytic solution from the opening of the exterior member 40 and impregnating the separator 35. Finally, the laminated film type secondary battery was completed by thermally sealing and sealing the opening of the exterior member 40 in a vacuum atmosphere.

(Experimental Example 1-4)
A procedure similar to that of Experimental Example 1-1 was performed except that the location of containing the fluororesin was changed to the positive electrode 33. When producing the positive electrode 33, after forming the positive electrode active material layer 34B on the positive electrode collector 33A, the positive electrode film 34C was formed on the positive electrode active material layer 34B by the same formation procedure as the negative electrode film 34C.

(Experimental Examples 1-5, 1-6)
A procedure similar to that in Experimental Examples 1-1 and 1-3 was performed, except that the fluororesin content was changed to the electrolytic solution. When preparing the electrolytic solution, before dissolving the electrolyte salt in the solvent, the fluororesin was dispersed in the solvent. In this case, the content of the fluororesin in the electrolytic solution was 1% by weight.

(Experimental Example 1-7)
A procedure similar to that of Experimental Examples 1-1 and 1-4 was performed, except that the location where the fluororesin was contained was changed to the positive electrode 33 and the negative electrode 34.

(Experimental example 1-8)
A procedure similar to that of Experimental Examples 1-1 to 1-3 was performed except that the fluororesin was not used, that is, the fluororesin was not included anywhere in the negative electrode 34, the positive electrode 33, or the electrolytic solution.

  When the cycle characteristics of the secondary batteries of Examples 1-1 to 1-8 were examined, the results shown in Table 1 were obtained.

In examining the cycle characteristics, first, in order to stabilize the battery state, one cycle charge / discharge was performed in an atmosphere at 23 ° C. Subsequently, the discharge capacity at the second cycle was measured by charging and discharging for one cycle in the same atmosphere. Subsequently, the discharge capacity at the 101st cycle was measured by charging and discharging 99 cycles in the same atmosphere. Finally, discharge capacity retention ratio (%) = (discharge capacity at the 101st cycle / discharge capacity at the second cycle) × 100 was calculated. In this case, as the charge condition, after charging at a constant current density of 3mA / cm ² until the battery voltage reached 4.2V, further reaches current density in 0.3 mA / cm ² at a constant voltage of 4.2V Charged until As discharge conditions, the battery was discharged at a constant current density of 3 mA / cm ² until the battery voltage reached 2.5V. The procedure and conditions for examining the cycle characteristics described above are the same for the series of experimental examples that follow.

  As shown in Table 1, when silicon was used as the negative electrode active material and a negative electrode active material layer (number of layers of negative electrode active material = 1 layer) was formed using a vapor phase method (electron beam evaporation method), In Experimental Examples 1-1 to 1-7 in which the positive electrode 33, the negative electrode 34, or the electrolytic solution contains a fluororesin, the discharge capacity retention rate was higher than in Experimental Example 1-8 that did not include the fluororesin.

  In this case, paying attention to the location where the fluororesin is contained, the discharge capacity retention rate increased in the order that the location was the electrolyte, the positive electrode 33 and the negative electrode 34. Further, when attention is paid to the number of containing locations of the fluororesin, the discharge capacity retention rate is higher in the case where there are a plurality of containing locations than in the case where the number of containing locations is one.

  For these reasons, in the secondary battery of the present invention, the positive electrode 33, the negative electrode 34 or the electrolyte contains at least one of the fluororesins represented by the formulas (1) and (2), thereby improving the cycle characteristics. Confirmed to do. In this case, it was also confirmed that the fluororesin-containing location is preferably in the order of the electrolyte, the positive electrode 33, and the negative electrode 34, and that the fluororesin-containing location is preferably more than one.

(Experimental examples 2-1 to 2-5)
Except having changed the number of layers of the negative electrode active material into six layers, the same procedure as Experimental Examples 1-1 to 1-3, 1-5, and 1-8 was performed. In the case of forming the negative electrode active material layer 34B, the silicon was laminated by sequentially depositing silicon while reciprocating the negative electrode current collector 34A at a deposition rate of 100 nm / second with respect to the evaporation source.

  When the cycle characteristics of the secondary batteries of Experimental Examples 2-1 to 2-5 were examined, the results shown in Table 2 were obtained.

  As shown in Table 2, even when silicon was used as the negative electrode active material and the negative electrode active material layer 34B (the number of negative electrode active material layers = 6 layers) was formed using a vapor phase method (electron beam evaporation method). The same results as in Table 1 were obtained. That is, in the experimental examples 2-1 to 2-4 in which the negative electrode 34 or the electrolytic solution contains a fluororesin, the discharge capacity retention rate was higher than in the experimental examples 2-5 that did not include the fluororesin.

  From this, it was confirmed that in the secondary battery of the present invention, the cycle characteristics were improved even when the number of layers of the negative electrode active material was changed.

(Experimental examples 3-1 to 3-5)
Except having changed the formation method of the negative electrode active material layer 34B into the sintering method, it went through the procedure similar to Experimental example 1-1 to 1-3, 1-5, and 1-8. When the negative electrode active material layer 34B is formed, first, 90 parts by mass of silicon powder (median diameter = 6 μm) as a negative electrode active material and 10 parts by mass of polyvinylidene fluoride as a negative electrode binder are mixed to form a negative electrode composite. Then, it was dispersed in N-methyl-2-pyrrolidone to obtain a paste-like negative electrode mixture slurry. Subsequently, the negative electrode mixture slurry was uniformly applied to both surfaces of the negative electrode current collector 34A, and then compression molded using a roll press machine. Finally, heating was performed in a vacuum atmosphere at 220 ° C. for 12 hours.

  When the cycle characteristics of the secondary batteries of Experimental Examples 3-1 to 3-5 were examined, the results shown in Table 3 were obtained.

  As shown in Table 3, when silicon was used as the negative electrode active material and the negative electrode active material layer 34B was formed using a sintering method, the same results as in Table 1 were obtained. That is, in the experimental examples 3-1 to 3-4 in which the negative electrode 34 or the electrolytic solution includes a fluororesin, the discharge capacity retention rate is higher than in the experimental examples 3-5 that do not include the fluororesin.

  From this, it was confirmed that in the secondary battery of the present invention, the cycle characteristics were improved even when the method for forming the negative electrode active material layer 34B was changed.

(Experimental examples 4-1 to 4-5)
Except that the negative electrode active material was changed to tin cobalt alloy (SnCo) and the formation method of the negative electrode active material layer 34B was changed to the coating method, Experimental Examples 1-1 to 1-3, 1-5, and 1-8 A similar procedure was followed. In the case of forming the negative electrode active material layer 34B, first, a powdered tin cobalt alloy (atomic ratio is Sn: Co = 80: 20) is formed using a gas atomization method, and then the median diameter is 15 μm. Crush classification Subsequently, 75 parts by mass of tin-cobalt alloy powder as a negative electrode active material, 20 parts by mass of flake graphite as a negative electrode conductive agent, and 5 parts by mass of carboxymethyl cellulose as a thickener were mixed into a negative electrode mixture, and then purified water To make a paste-like negative electrode mixture slurry. Finally, the negative electrode mixture slurry was uniformly applied to both surfaces of the negative electrode current collector 34A, and then compression molded using a roll press. In addition, after exposing the cross section of the completed negative electrode 34 using FIB (focused ion beam) method, it analyzed using Auger Electron Spectroscopy (AES), The negative electrode collector 34A and negative electrode It was confirmed that the active material layer 34B was alloyed in at least a part of the interface.

  When the cycle characteristics of the secondary batteries of Examples 4-1 to 4-5 were examined, the results shown in Table 4 were obtained.

  As shown in Table 4, when a tin cobalt alloy was used as the negative electrode active material and the negative electrode active material layer 34B was formed using a coating method, the same results as in Table 1 were obtained. That is, in Experimental Examples 4-1 to 4-4 in which the negative electrode 34 or the electrolytic solution contains a fluororesin, the discharge capacity retention rate was higher than in Experimental Example 4-5 that did not include the fluororesin.

  From this, it was confirmed that in the secondary battery of the present invention, the cycle characteristics were improved even when the type of the negative electrode active material and the method for forming the negative electrode active material layer 34B were changed.

(Experimental examples 5-1 to 5-5)
The procedure was the same as those of Experimental Examples 1-1 to 1-3, 1-5, and 1-8 except that the negative electrode active material was changed to MCMB and the formation method of the negative electrode active material layer 34B was changed to the coating method. Passed. When forming the negative electrode active material layer 34B, first, 87 parts by mass of MCMB (median diameter = 25 μm) as the negative electrode active material, 3 parts by mass of artificial graphite as the negative electrode conductive agent, and polyvinylidene fluoride as the negative electrode binder After mixing 10 parts by mass with the negative electrode mixture, the mixture was dispersed in N-methyl-2-pyrrolidone to obtain a paste-like negative electrode mixture slurry. After that, the negative electrode mixture slurry was uniformly applied to both surfaces of the negative electrode current collector 34A and dried, followed by compression molding using a roll press machine.

  When the cycle characteristics of the secondary batteries of Examples 5-1 to 5-5 were examined, the results shown in Table 5 were obtained.

  As shown in Table 5, when MCMB was used as the negative electrode active material and the negative electrode active material layer 34B was formed using a coating method, the same results as in Table 1 were obtained. In other words, in Experimental Examples 5-1 to 5-4 in which the negative electrode 34 or the electrolytic solution contains a fluororesin, the discharge capacity retention rate was higher than in Experimental Example 5-5 that did not include the fluororesin.

  From this, it was confirmed that in the secondary battery of the present invention, the cycle characteristics were improved even when the type of the negative electrode active material and the method for forming the negative electrode active material layer 34B were changed.

(Experimental examples 6-1 to 6-12)
Except that the composition of the electrolytic solution was changed as shown in Table 6, the same procedure as in Experimental Examples 2-1 and 2-5 was performed. In this case, as a solvent, in addition to EC and DEC, 4-fluoro-1,3-dioxolane-2 which is a cyclic carbonate having propylene carbonate (PC) or halogen represented by formula (4) as a constituent element is used. -One (FEC) or 4,5-difluoro-1,3-dioxolan-2-one (DFEC), vinylene carbonate (VC) which is a cyclic carbonate having an unsaturated carbon bond shown in Formula (5), Propene sultone (PRS) as sultone and sulfopropionic anhydride (SPAH) as acid anhydride were used. Further, as the electrolyte salt, lithium tetrafluoroborate (LiBF ₄ ), the compound represented by the formula (8-1) or the formula (8-6) which is the compound represented by the formula (8), the formula (8) The compound shown in Formula (12-2) which is the compound shown in 12) was used. When LiBF ₄ or the like is added as an electrolyte salt, the content of LiPF ₆ is 0.9 mol / kg with respect to the solvent, and the content of LiBF ₄ or the like is 0.1 mol / kg with respect to the solvent. . Moreover, when adding above-mentioned PRS and SPAH as a solvent, content in those solvents was 1 weight%.

  When the cycle characteristics of the secondary batteries of Examples 6-1 to 6-12 were examined, the results shown in Table 6 were obtained.

  As shown in Table 6, the same results as in Table 1 were obtained even when the composition of the electrolytic solution was changed. In other words, in Experimental Examples 6-1 to 6-11 in which the negative electrode 34 includes a fluororesin, the discharge capacity retention rate is higher than in Experimental Example 6-12 that does not include the fluorine resin.

In this case, when FEC or the like was added as a solvent or LiBF ₄ or the like was added as an electrolyte salt, the discharge capacity retention rate was higher than when no such was added.

From these facts, it was confirmed that in the secondary battery of the present invention, the cycle characteristics were improved even when the composition of the electrolyte, that is, the type of the solvent and the electrolyte salt was changed. In this case, it was confirmed that the characteristics were further improved by adding FEC or the like as a solvent or LiBF ₄ or the like as an electrolyte salt.

(Experimental examples 7-1 to 7-4)
When forming the negative electrode active material layer 34B, after forming a plurality of particulate negative electrode active materials, as shown in Table 7, examples were formed except that an oxide-containing film and a metal material were formed in this order. The same procedure as in 2-1 to 2-4 was performed. In the case of forming an oxide-containing film, silicon oxide (SiO ₂ ) was deposited on the surface of the negative electrode active material using a liquid phase deposition method. In this case, the negative electrode current collector 34A on which the negative electrode active material is formed is immersed for 3 hours in a solution obtained by dissolving boron as an anion scavenger in hydrofluoric acid, and silicon is deposited on the surface of the negative electrode active material. After the oxide was precipitated, it was washed with water and dried under reduced pressure. In the case of forming a metal material, a nickel (Ni) plating film was grown using an electrolytic plating method while supplying air to the plating bath. In this case, a nickel plating solution manufactured by Nippon Kogyo Chemical Co., Ltd. was used as the plating solution, the current density was set to 2 A / dm ² to 10 A / dm ² , and the plating rate was set to 10 nm / second.

  When the cycle characteristics of the secondary batteries of Experimental Examples 7-1 to 7-4 were examined, the results shown in Table 7 were obtained.

  As shown in Table 7, the same results as in Table 1 were obtained when the oxide-containing film and the metal material were formed. That is, in the experimental examples 7-1 to 7-4 in which the negative electrode 34 or the electrolytic solution contains a fluororesin, the discharge capacity retention rate was higher than in the experimental examples 2-5 that did not contain the fluororesin.

  In this case, paying attention to the presence or absence of the oxide-containing film and the metal material, the discharge capacity retention rate was higher in the case where the oxide-containing film and the metal material were formed than in the case where they were not formed.

  From these results, it was confirmed that in the secondary battery of the present invention, the cycle characteristics were improved even when the oxide-containing film and the metal material were formed. In this case, it was confirmed that the characteristics were further improved by forming the oxide-containing film and the metal material.

  In addition, in above-mentioned Table 1-Table 7, only the result at the time of using the compound shown to Formula (1-1) etc. is shown as a fluororesin shown to Formula (1) and Formula (2), The result in the case of using the other compound (For example, the compound shown to Formula (1-2) etc.) is not shown. However, since the compound shown in the formula (1-2) performs the same function as the compound shown in the formula (1-1), etc., other compounds are used or a series of compounds are mixed. In some cases, similar results are obtained.

  The radical scavenging compound represented by the formula (1) has been described above in terms of a chain carbonate having the halogen represented by the formula (3) as a constituent element and a cyclic carbonate having the halogen represented by the formula (4) as a constituent element. The same applies to the cyclic carbonate having an unsaturated carbon bond represented by the formulas (5) to (7) or the compounds represented by the formulas (8) to (13). That is, if a compound corresponding to a chain carbonate having a halogen represented by the above formula (3) as a constituent element is used as a solvent or an electrolyte salt, the compound is not actually used in Tables 1 to 7. Even if it is a compound, the same result as the case where the compound actually used in Table 1-Table 7 is used is obtained.

  As is clear from the results of Tables 1 to 7 above, in the secondary battery of the present invention, at least one of the positive electrode, the negative electrode, and the electrolyte is a fluororesin represented by Formula (1) and Formula (2). By including at least one of the above, cycle characteristics are improved without depending on the type of negative electrode active material, the method of forming the negative electrode active material layer, the composition of the electrolyte, the presence of oxide-containing films and metal materials, etc. Can be made. In this case, in particular, the characteristics can be further improved if the negative electrode contains a fluororesin.

  In addition, since the increase rate of the discharge capacity retention rate is larger when a high capacity material such as silicon or tin cobalt alloy is used as a negative electrode active material than when a carbon material such as MCMB is used, the latter In some cases, a higher effect can be obtained. This result is considered that when a high-capacity material is used as the negative electrode active material, the electrolyte is more easily decomposed than when a carbon material is used, and thus the effect of suppressing the decomposition of the electrolyte is conspicuously exhibited.

  The present invention has been described with reference to the embodiments and examples. However, the present invention is not limited to the embodiments described in the above embodiments and examples, and various modifications can be made. For example, the use application of the negative electrode, the positive electrode or the electrolyte of the present invention is not necessarily limited to the secondary battery, and may be an electrochemical device other than the secondary battery. Other applications include, for example, capacitors.

  In the above-described embodiments and examples, the lithium ion secondary battery in which the capacity of the negative electrode is expressed based on insertion and extraction of lithium ions has been described as the type of the secondary battery, but is not necessarily limited thereto. It is not a thing. The secondary battery of the present invention has a negative electrode capacity capable of inserting and extracting lithium ions by making the charging capacity of the negative electrode material smaller than the charging capacity of the positive electrode. The present invention can be similarly applied to a secondary battery including a capacity accompanying the precipitation and dissolution of lithium and represented by the sum of the capacities.

  In the above-described embodiments and examples, the case where the electrolytic solution or the gel electrolyte in which the electrolytic solution is held in the polymer compound is used as the electrolyte of the secondary battery of the present invention has been described. The electrolyte may be used. Other electrolytes include, for example, a mixture of an ion conductive inorganic compound such as ion conductive ceramics, ion conductive glass or ionic crystal and an electrolyte, or a mixture of another inorganic compound and an electrolyte. Examples thereof include a mixture of these inorganic compounds and a gel electrolyte, and a solid electrolyte in which an electrolyte salt and an ion conductive polymer compound are mixed.

  Further, in the above-described embodiments and examples, the case where the battery structure is a cylindrical type or a laminate film type and the case where the battery element has a winding structure have been described as examples, but the battery of the present invention is The present invention can be similarly applied to a case where other battery structures such as a square shape, a coin shape, or a button shape are provided, and a case where the battery element has another structure such as a laminated structure.

  In the above-described embodiments and examples, the case where lithium is used as the electrode reactant has been described. However, other Group 1A elements such as sodium (Na) or potassium (K), magnesium (Mg) or calcium ( You may use 2A group elements, such as Ca), and other light metals, such as aluminum. Since the effect of the present invention should be obtained without depending on the type of the electrode reactant, the same effect can be obtained even if the type of the electrode reactant is changed.

It is sectional drawing showing the structure of the secondary battery (1st secondary battery) which concerns on one embodiment of this invention. It is sectional drawing which expands and represents a part of winding electrode body shown in FIG. FIG. 3 is an enlarged cross-sectional view illustrating a configuration of a negative electrode illustrated in FIG. 2. It is sectional drawing showing the structure of the negative electrode of a reference example. FIG. 3 is an SEM photograph showing a cross-sectional structure of the negative electrode shown in FIG. 2 and a schematic diagram thereof. FIG. 3 is an SEM photograph showing another cross-sectional structure of the negative electrode shown in FIG. 2 and a schematic diagram thereof. It is sectional drawing showing the structure of the secondary battery (other 1st secondary battery) which concerns on one embodiment of this invention. It is sectional drawing along the VIII-VIII line of the wound electrode body shown in FIG. It is sectional drawing which expands and represents a part of winding electrode body shown in FIG. It is sectional drawing showing the structure of the secondary battery (2nd secondary battery) which concerns on one embodiment of this invention. It is sectional drawing showing the structure of the secondary battery (other 2nd secondary battery) which concerns on one embodiment of this invention. It is sectional drawing showing the structure of the secondary battery (3rd secondary battery) which concerns on one embodiment of this invention. It is sectional drawing showing the structure of the secondary battery (other 3rd secondary battery) which concerns on one embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Battery can, 12, 13 ... Insulation board, 14 ... Battery cover, 15 ... Safety valve mechanism, 15A ... Disc board, 16 ... Heat sensitive resistance element, 17 ... Gasket, 20, 30 ... Winding electrode body, 21, 33 ... Positive electrode, 21A, 33A ... Positive electrode current collector, 21B, 33B ... Positive electrode active material layer, 21C, 33C ... Positive electrode coating, 22, 34 ... Negative electrode, 22A, 34A ... Negative electrode current collector, 22B, 34B ... Negative electrode active material Layer, 22C, 34C ... negative electrode coating, 23, 35 ... separator, 24 ... center pin, 25, 31 ... positive electrode lead, 26, 32 ... negative electrode lead, 36 ... electrolyte layer, 37 ... protective tape, 40 ... exterior member, 41 ... adhesion film, 221 ... negative electrode active material particles, 222 ... oxide-containing film, 224 (224A, 224B) ... gap, 225 ... gap, 226 ... metal material.

Claims (16)

A positive electrode including a positive electrode active material capable of occluding and releasing an electrode reactant, a negative electrode including a negative electrode active material capable of occluding and releasing the electrode reactant, an electrolyte including a nonaqueous solvent and an electrolyte salt And comprising
At least one of the positive electrode and the negative electrode includes a secondary battery including at least one of fluororesins represented by Formula (1) and Formula (2).

( Each of X1 and X2 is a perfluoroalkyl group, a carboxylic acid alkali metal base, a sulfonic acid alkali metal base, a carboxylic acid alkaline earth metal base, or a sulfonic acid alkaline earth metal base. At least one is a carboxylic acid alkali metal base, a sulfonic acid alkali metal base, a carboxylic acid alkaline earth metal base, or a sulfonic acid alkaline earth metal base, h and k satisfy h> 0, k> 0, and h + k = 1 . .)

(X3 is a carboxylic acid alkali metal base, a sulfonic acid alkali metal base, a carboxylic acid alkaline earth metal base, or a sulfonic acid alkaline earth metal base.) X1 and X2 in the formula (1) are both a carboxylic acid alkali metal base or a carboxylic acid alkaline earth metal base, and X3 in the formula (2) is a carboxylic acid alkali metal base or carboxylic acid alkaline earth. The secondary battery according to claim 1, which is a similar metal base. The secondary battery according to claim 1, wherein the electrode reactant is lithium ion, and the alkali metal carboxylate or the alkali metal sulfonate is a lithium base. The fluororesin shown in the formula (1) is a compound represented by the formula (1-1) to the formula (1-6), and the fluororesin shown in the formula (2) is a formula (2-1). The secondary battery according to claim 1, which is a compound represented by formula (2-4).

The fluororesin shown in the formula (1) is a compound shown in the formula (1-1), and the fluororesin shown in the formula (2) is a compound shown in the formula (2-1). The secondary battery according to claim 4. The negative electrode has a negative electrode film formed on the negative electrode active material layer after the negative electrode active material layer is formed on the negative electrode current collector, and the negative electrode film has the formula (1) and the formula (2) The secondary battery according to claim 1, comprising at least one of the fluororesins shown in FIG. The negative electrode active material is a plurality of particles, the negative electrode active material layer includes an oxide-containing film that covers a surface of the negative electrode active material, and the oxide-containing film is an oxide of silicon (Si) The secondary battery according to claim 6, comprising at least one of oxides of germanium (Ge) and tin (Sn). The negative electrode active material is in a plurality of particles, and the negative electrode active material layer includes a metal material that does not alloy with the electrode reactant in a gap inside the negative electrode active material layer, and the metal material includes iron (Fe), cobalt The secondary battery according to claim 6, comprising at least one of (Co), nickel (Ni), zinc (Zn), and copper (Cu). The secondary battery according to claim 1, wherein the negative electrode active material has at least one of silicon and tin as a constituent element. The positive electrode has a positive electrode film formed on the positive electrode active material layer after the positive electrode active material layer is formed on the positive electrode current collector, and the positive electrode film has the formula (1) and the formula ( The secondary battery according to claim 1, comprising at least one of the fluororesins shown in 2). The secondary battery according to claim 1, wherein the electrolyte includes at least one of fluororesins represented by the formulas (1) and (2). The non-aqueous solvent includes a chain carbonate having a halogen represented by formula (3) as a constituent element, a cyclic carbonate having a halogen represented by formula (4) as a constituent element, formulas (5) to ( The secondary battery according to claim 1, comprising at least one of a cyclic carbonate having an unsaturated carbon bond represented by 7), a sultone, and an acid anhydride.

(R11 to R16 are a hydrogen group, a halogen group, an alkyl group or a halogenated alkyl group, and at least one of them is a halogen group or a halogenated alkyl group.)

(R17 to R20 are a hydrogen group, a halogen group, an alkyl group or a halogenated alkyl group, and at least one of them is a halogen group or a halogenated alkyl group.)

(R21 and R22 are a hydrogen group or an alkyl group.)

(R23 to R26 are a hydrogen group, an alkyl group, a vinyl group, or an allyl group, and at least one of them is a vinyl group or an allyl group.)

(R27 is an alkylene group.) The electrolyte salt includes lithium hexafluorophosphate (LiPF ₆ ), lithium tetrafluoroborate (LiBF ₄ ), lithium perchlorate (LiClO ₄ ), lithium hexafluoroarsenate (LiAsF ₆ ), formula (8 The secondary battery according to claim 1, comprising at least one of compounds represented by formula (10) to formula (10) and compounds represented by formula (11) to formula (13).

(X31 is a group 1 element or group 2 element in the long-period periodic table, or aluminum (Al). M31 is a transition metal element, or a group 13 element, group 14 element, or group 15 element in the long-period periodic table. R31 is a halogen group, Y31 is — (O═) C—R32—C (═O) —, — (O═) C—C (R33) ₂ — or — (O═) C—C ( ═O) —, wherein R32 is an alkylene group, a halogenated alkylene group, an arylene group or a halogenated arylene group, and R33 is an alkyl group, a halogenated alkyl group, an aryl group or a halogenated aryl group. A3 is an integer of 1 to 4, b3 is 0, 2 or 4, and c3, d3, m3 and n3 are integers of 1 to 3.)

(X41 is a group 1 element or group 2 element in the long periodic table. M41 is a transition metal element, or a group 13, element or group 15 element in the long period periodic table. Y41 is − ( O =) C- (C (R41 ) 2) b4 -C (= O) -, - (R43) 2 C- (C (R42) 2) c4 -C (= O) -, - (R43) 2 C -(C (R42) ₂ ) _c4 -C (R43) ₂ -,-(R43) ₂ C- (C (R42) ₂ ) _c4 -S (= O) ₂ -,-(O =) ₂ S- ( C (R42) ₂ ) _d4- S (= O) _2- or-(O =) C- (C (R42) ₂ ) _d4- S (= O) _2- where R41 and R43 are hydrogen groups. , An alkyl group, a halogen group or a halogenated alkyl group, at least one of each being a halogen group or a halogenated alkyl group. R42 is a hydrogen group, an alkyl group, a halogen group or a halogenated alkyl group, wherein a4, e4 and n4 are 1 or 2, b4 and d4 are integers of 1 to 4, and c4 Is an integer from 0 to 4, and f4 and m4 are integers from 1 to 3.)

(X51 is a group 1 element or group 2 element in the long-period periodic table. M51 is a transition metal element, or a group 13, element or group 15 element in the long-period periodic table. Rf is fluorinated. An alkyl group or a fluorinated aryl group, each having 1 to 10 carbon atoms Y51 is — (O═) C— (C (R51) ₂ ) _d5 —C (═O) —, — (R52); ₂ C- (C (R51) ₂ ) _d5 -C (= O)-,-(R52) ₂ C- (C (R51) ₂ ) _d5 -C (R52) ₂ -,-(R52) ₂ C- ( _{C (R51) 2) d5 -S} (= O) 2 -, - (O =) 2 S- (C (R51) 2) e5 -S (= O) 2 - or - (O =) C- (C _{(R51) 2) e5 -S (} = O) 2 -. is, however, R51 is a hydrogen group, an alkyl group, a halogen group, or a halogen Kaa R52 is a hydrogen group, an alkyl group, a halogen group or a halogenated alkyl group, at least one of which is a halogen group or a halogenated alkyl group, wherein a5, f5 and n5 are 1 or 2; B5, c5 and e5 are integers of 1 to 4, d5 is an integer of 0 to 4, and g5 and m5 are integers of 1 to 3.)

(M and n are integers of 1 or more.)

(R61 is a linear or branched perfluoroalkylene group having 2 to 4 carbon atoms.)

(P, q and r are integers of 1 or more.) At least one of a positive electrode including a positive electrode active material capable of occluding and releasing an electrode reactant and a negative electrode including a negative electrode active material capable of occluding and releasing the electrode reactant is represented by the formula (1) And the manufacturing method of the secondary battery which contains at least 1 sort (s) among the fluororesins represented by Formula (2).

( Each of X1 and X2 is a perfluoroalkyl group, a carboxylic acid alkali metal base, a sulfonic acid alkali metal base, a carboxylic acid alkaline earth metal base, or a sulfonic acid alkaline earth metal base. At least one is a carboxylic acid alkali metal base, a sulfonic acid alkali metal base, a carboxylic acid alkaline earth metal base, or a sulfonic acid alkaline earth metal base, h and k satisfy h> 0, k> 0, and h + k = 1 . .)

(X3 is a carboxylic acid alkali metal base, a sulfonic acid alkali metal base, a carboxylic acid alkaline earth metal base, or a sulfonic acid alkaline earth metal base.) After the negative electrode active material layer is formed on the negative electrode current collector, it has a negative electrode film formed on the negative electrode active material layer,
The negative electrode active material layer includes a negative electrode active material capable of occluding and releasing an electrode reactant,
The said negative electrode film is a negative electrode for secondary batteries containing at least 1 sort (s) of the fluororesins represented by Formula (1) and Formula (2).

( Each of X1 and X2 is a perfluoroalkyl group, a carboxylic acid alkali metal base, a sulfonic acid alkali metal base, a carboxylic acid alkaline earth metal base, or a sulfonic acid alkaline earth metal base. At least one is a carboxylic acid alkali metal base, a sulfonic acid alkali metal base, a carboxylic acid alkaline earth metal base, or a sulfonic acid alkaline earth metal base, h and k satisfy h> 0, k> 0, and h + k = 1 . .)

(X3 is a carboxylic acid alkali metal base, a sulfonic acid alkali metal base, a carboxylic acid alkaline earth metal base, or a sulfonic acid alkaline earth metal base.) After the positive electrode active material layer is formed on the positive electrode current collector, it has a positive electrode film formed on the positive electrode active material layer,
The positive electrode active material layer includes a positive electrode active material capable of occluding and releasing an electrode reactant.
The said positive electrode film is a positive electrode for secondary batteries containing at least 1 sort (s) of the fluororesins represented by Formula (1) and Formula (2).

( Each of X1 and X2 is a perfluoroalkyl group, a carboxylic acid alkali metal base, a sulfonic acid alkali metal base, a carboxylic acid alkaline earth metal base, or a sulfonic acid alkaline earth metal base. At least one is a carboxylic acid alkali metal base, a sulfonic acid alkali metal base, a carboxylic acid alkaline earth metal base, or a sulfonic acid alkaline earth metal base, h and k satisfy h> 0, k> 0, and h + k = 1 . .)

(X3 is a carboxylic acid alkali metal base, a sulfonic acid alkali metal base, a carboxylic acid alkaline earth metal base, or a sulfonic acid alkaline earth metal base.)

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