JP2010165508A - Negative electrode and secondary battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a secondary battery capable of improving cycle characteristics. <P>SOLUTION: The secondary battery has a positive electrode 21, a negative electrode 22, and an electrolyte, and the electrolyte is impregnated into a separator 23 arranged between the positive electrode 21 and the negative electrode 22. A negative electrode active material layer 22B of the negative electrode 22 contains a crystal negative electrode active material capable of occluding and discharging lithium ions. The negative electrode active material contains silicon and iron as a constituent, and the content of the iron in the negative electrode active material is 0.05 wt.% or more. Resistance becomes lower while physical strength of the negative electrode active material layer 22B is increased. Furthermore, the negative electrode active material layer 22B is hardly expanded and contracted at the time of charge and discharge. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a negative electrode capable of occluding and releasing an electrode reactant and a secondary battery using the same.

  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 small and lightweight and capable of obtaining a high energy density is in progress.

  Among them, lithium ion secondary batteries that use the insertion and extraction of lithium ions for charge / discharge reactions are widely put into practical use because they have 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 capable of inserting and extracting lithium ions. The negative electrode has a negative electrode active material layer containing a negative electrode active material capable of inserting and extracting lithium ions.

  Carbon materials are widely used as the negative electrode active material. In recent years, as the performance of portable electronic devices has been improved and the functionality has been increased, further improvement in battery capacity has been demanded. Therefore, the use of silicon instead of carbon materials has been studied. This is because the theoretical capacity of silicon (4199 mAh / g) is much larger than the theoretical capacity of graphite (372 mAh / g), so that significant improvement in battery capacity is expected.

  When silicon is used as the negative electrode active material, a vapor phase method such as a vapor deposition method or a thermal spray method is used as a method for forming the negative electrode active material layer. Since silicon is directly deposited on the surface of the negative electrode current collector and the negative electrode active material is connected (fixed) to the surface of the negative electrode current collector, the negative electrode active material layer is less likely to expand and contract during charge / discharge. is there.

  In this case, in particular, when the thermal spraying method is used, the performance stability of the negative electrode becomes higher than when the vapor deposition method is used. This is because the deposited film of silicon becomes crystalline, so that the physical properties of the negative electrode active material hardly change over time.

Several techniques have been proposed for improving the performance of lithium ion secondary batteries using silicon as the negative electrode active material. Specifically, in order to establish a new battery system, a silicon thin film including a crystalline region and an amorphous region is formed using a vapor deposition method or a thermal spraying method (see, for example, Patent Document 1). In order to improve the high temperature storage resistance at low state of charge, the crystallinity of the silicon thin film peak half width is 10 cm ^-1 or more 30 cm ^-1 or less with the Raman shift is equal to or less than 490 cm ^-1 or more 500 cm ^-1 (For example, refer to Patent Document 2). In addition, in order to produce an electrode using active material particles without using a slurry or the like, silicon particles are sprayed on the surface of a current collector while being dispersed in an air stream without being melted or deposited (for example, Patent Documents). 3). Further, in order to improve cycle characteristics and the like, a silicon thin film containing cobalt or chromium is formed by using a vapor deposition method or a thermal spraying method (see, for example, Patent Document 4). In order to improve cycle characteristics and the like, a metal element such as aluminum is contained in a silicon thin film having a purity of 99% or less (see, for example, Patent Document 5).

Japanese Patent Laid-Open No. 2002-083594 JP 2007-194207 A JP-A-2005-310502 JP 2003-007295 A JP 2005-044814 A

  Since the silicon film deposited by the thermal spraying method is greatly affected by the physical properties of the silicon itself, it becomes very hard and physically brittle and has high resistance. As a result, the cycle characteristics, which are important characteristics of the secondary battery, are likely to deteriorate. Moreover, in recent years, portable electronic devices have become more sophisticated and multifunctional, and their power consumption has increased, so that charging and discharging of secondary batteries tend to be repeated frequently. As a result, even if the usage frequency of the secondary battery is increased, the cycle characteristics are likely to deteriorate. Therefore, in order to stably use the secondary battery at a high frequency, further improvement in cycle characteristics is desired.

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

  The negative electrode of the present invention includes a crystalline negative electrode active material capable of occluding and releasing an electrode reactant, the crystalline negative electrode active material includes silicon and iron as constituent elements, and a crystalline negative electrode active material The iron content is 0.05% by weight or more. The secondary battery of the present invention includes a positive electrode and a negative electrode, an electrolyte containing a solvent and an electrolyte salt, and the negative electrode has the above-described configuration.

  According to the negative electrode of the present invention, the crystalline negative electrode active material containing silicon and iron is contained, and the iron content in the crystalline negative electrode active material is 0.05% by weight or more. In this case, the physical strength of the negative electrode active material is higher compared to the case where only silicon is contained and iron is not contained, or the case where iron is contained and the content is less than 0.05% by weight. And the resistance decreases. In addition, the negative electrode active material is less likely to expand and contract during the electrode reaction. Therefore, it can contribute to the performance improvement of the electrochemical device using a negative electrode. For this reason, according to the secondary battery using the negative electrode of the present invention, cycle characteristics can be improved.

It is sectional drawing showing the structure of the negative electrode which concerns on one embodiment of this invention. FIG. 2 is an SEM photograph showing a cross-sectional structure of the negative electrode shown in FIG. 1 and a schematic diagram thereof. FIG. 2 is an SEM photograph showing another cross-sectional structure of the negative electrode shown in FIG. 1 and a schematic diagram thereof. It is sectional drawing showing the structure of the 1st secondary battery provided with the negative electrode which concerns on one embodiment of this invention. It is sectional drawing along the VV line of the 1st secondary battery shown in FIG. It is sectional drawing showing the structure of the 2nd secondary battery provided with the negative electrode 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. It is a perspective view showing the structure of the 3rd secondary battery provided with the negative electrode which concerns on one embodiment of this invention. It is sectional drawing along the IX-IX line of the winding electrode body shown in FIG. It is a figure showing the correlation between Fe content and a discharge capacity maintenance factor. It is a figure showing the correlation between a half value width and a discharge capacity maintenance factor. It is a figure showing the correlation between oxygen content and a discharge capacity maintenance factor. It is a figure showing the correlation between the number of high oxygen content area | regions, and a discharge capacity maintenance factor. It is a figure showing the correlation between ten-point average roughness Rz and a discharge capacity maintenance factor.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The order of explanation is as follows.

1. Negative electrode Electrochemical device using a negative electrode (secondary battery)
2-1. First secondary battery (battery structure: square)
2-2. Second secondary battery (battery structure: cylindrical)
2-3. Third secondary battery (battery structure: laminate film type)

<1. Negative electrode>
[Overall structure of negative electrode]
FIG. 1 shows a cross-sectional configuration of a negative electrode according to an embodiment of the present invention. This negative electrode is used for an electrochemical device such as a secondary battery, for example, and has a negative electrode active material layer 2 on a negative electrode current collector 1.

[Negative electrode current collector]
The negative electrode current collector 1 is preferably made of a material having good electrochemical stability, electrical conductivity, and mechanical strength. Examples of such a material include copper, nickel, and stainless steel, and copper is preferable. This is because high electrical conductivity can be obtained.

  The surface of the negative electrode current collector 1 is preferably roughened. This is because the adhesion of the negative electrode active material layer 2 to the negative electrode current collector 1 is improved by a so-called anchor effect. In this case, the surface of the negative electrode current collector 1 may be roughened at least in a region facing the negative electrode active material layer 2. Examples of the roughening method include a method of forming fine particles by electrolytic treatment. This electrolytic treatment is a method of forming irregularities by forming fine particles on the surface of the negative electrode current collector 1 by an electrolytic method in an electrolytic bath. The copper foil produced by the electrolytic method is generally called “electrolytic copper foil”. In addition, examples of the roughening method include a method of sandblasting a rolled copper foil.

  The ten-point average roughness Rz of the surface of the negative electrode current collector 1 is not particularly limited, but is preferably 1.5 μm or more. In this case, it is more preferably 1.5 μm or more and 30 μm or less, and further preferably 3 μm or more and 30 μm or less. This is because the adhesion of the negative electrode active material layer 2 to the negative electrode current collector 1 becomes higher. In detail, when it is smaller than 1.5 μm, there is a possibility that sufficient adhesion cannot be obtained, and when it is larger than 30 μm, there is a possibility that the adhesion is deteriorated.

[Negative electrode active material layer]
The negative electrode active material layer 2 is provided on both surfaces of the negative electrode current collector 1, for example. However, the negative electrode active material layer 2 may be provided only on one side of the negative electrode current collector 1.

  This negative electrode active material layer 2 contains, as a negative electrode active material, any one or more of negative electrode materials capable of occluding and releasing electrode reactants such as lithium ions, for example. Other materials such as a negative electrode conductive agent may be included.

  As the negative electrode material, a material containing silicon and iron as constituent elements and having an iron content of 0.05% by weight or more (hereinafter referred to as “silicon iron-containing material”) is preferable. This is because silicon having excellent ability to occlude and release electrode reactants can provide high energy density. In addition, since iron, which is a metal element, is included in addition to silicon, the physical strength of the negative electrode material increases and the resistance decreases. Further, the expansion and contraction during the electrode reaction is suppressed. The iron content is not particularly limited as long as it is 0.05% by weight or more, but among them, 0.05% by weight or more and 8.8% by weight or less is preferable. This is to prevent the original function of the negative electrode from deteriorating due to the too low ratio of silicon. The state of the silicon-iron-containing material may be a state where silicon and iron form a complete alloy, a state where both are mixed (compound state), or a state where these states are mixed. You may be in a state.

  The silicon iron-containing material that is the negative electrode active material is crystalline. This is because the physical properties of the negative electrode active material contributing to the performance of the negative electrode are less likely to change with time than when it is non-crystalline. In addition, the negative electrode active material is less likely to expand and contract during the electrode reaction, and the adhesion of the negative electrode active material to the negative electrode current collector 1 is increased. Such a crystalline negative electrode active material is formed by, for example, a thermal spraying method. However, the negative electrode active material may be formed by a method other than the thermal spraying method as long as it becomes crystalline.

  The crystal state (whether crystalline or non-crystalline) of the negative electrode active material is confirmed by X-ray diffraction. Specifically, as a result of analyzing the negative electrode active material, it is crystalline when a sharp peak is detected, and is amorphous when a broad peak is detected.

  The half width (2θ) of the diffraction peak on the (111) crystal plane of the negative electrode active material obtained by X-ray diffraction is not particularly limited, but is preferably 20 ° or less. The crystallite size resulting from the same crystal plane is not particularly limited, but is preferably 100 nm or more. This is because the physical properties of the negative electrode active material are less likely to change with time, and the diffusibility of the electrode reactant is less likely to decrease.

  The silicon iron-containing material that is the negative electrode active material may contain, for example, an additional metal element other than iron as a constituent element. This is because the advantages of the above-described silicon iron-containing material are further promoted. Such an additional metal element is not particularly limited, but at least one of aluminum, calcium, chromium, magnesium, manganese, nickel, potassium, copper, and titanium is preferable, and aluminum and calcium are more preferable. This is because a high effect can be obtained. The silicon iron-containing material containing aluminum and calcium as the additional metal element may be so-called metal silicon (metasilicon). This metallic silicon is a material specified by JIS standard G2312.

  When the silicon iron-containing material contains the above-described additional metal element as a constituent element, the total content of iron and the additional metal element is not particularly limited, but is preferably 0.2% by weight or more, More preferably, it is 0.2 weight% or more and 8.8 weight% or less. This is because a higher effect can be obtained.

  The crystalline negative electrode active material is preferably in the form of a plurality of particles connected to the surface of the negative electrode current collector 1. This is because the negative electrode active material is physically fixed to the negative electrode current collector 1, and thus the negative electrode active material is less likely to expand and contract during the electrode reaction.

  The above-mentioned “negative electrode active material is connected to the negative electrode current collector 1” means that the negative electrode material is directly deposited on the surface of the negative electrode current collector 1 to form the negative electrode active material. I mean. For this reason, when the negative electrode active material is formed using, for example, a coating method or a sintering method, the negative electrode active material is not connected to the negative electrode current collector 1. In this case, the negative electrode active material is indirectly connected to the negative electrode current collector 1 via another material (for example, a binder), or is simply connected to the negative electrode current collector 1. Because they are only adjacent.

  Note that the crystalline negative electrode active material may be at least partially connected to the negative electrode current collector 1. This is because if only a part of the negative electrode current collector 1 is connected to the negative electrode current collector 1, the adhesion of the negative electrode active material to the negative electrode current collector 1 becomes higher than when it is not connected at all. When the negative electrode active material is partially connected to the negative electrode current collector 1, the negative electrode active material has a portion that contacts the negative electrode current collector 1 and a portion that does not contact the negative electrode current collector 1.

  When the negative electrode active material does not have a non-contact portion, the negative electrode active material is in contact with the negative electrode current collector 1 throughout, so that the electron conductivity between the two is increased. On the other hand, when the negative electrode active material expands and contracts during the electrode reaction, there is no escape space (relaxation space), so that the negative electrode current collector 1 may be deformed due to the influence of stress due to the expansion and contraction. is there.

  On the other hand, when the negative electrode active material has a non-contact portion, there is a escape space (relaxation space) when the negative electrode active material expands and contracts during the electrode reaction. The negative electrode current collector 1 becomes difficult to be deformed under the influence of the stress due to the above. On the other hand, since there is a portion where the negative electrode active material is not in contact with the negative electrode current collector 1, there is a possibility that the electronic conductivity between the two becomes low.

  When the crystalline negative electrode active material is in the form of a plurality of particles, the shape of the particles may be any shape, but among them, at least a part of the shape is preferably flat. This is because the negative electrode active materials are likely to overlap each other (is more likely to come into contact), so that the number of contact points between the negative electrode active materials increases. Thereby, the electronic conductivity in the negative electrode active material layer 2 becomes high. This “flat shape” means a shape extending in a direction intersecting the thickness direction of the negative electrode (negative electrode active material layer 2) (direction along the surface of the negative electrode current collector 1). That is, it has a substantially elliptical shape having a major axis in a direction along the surface of the negative electrode current collector 1 and a minor axis in a direction intersecting the surface. This flat shape is one of the features seen when, for example, a negative electrode material is deposited by a thermal spraying method. In this case, if the melting temperature of the negative electrode material is increased, the negative electrode active material tends to become flat.

  This negative electrode active material may have a single layer structure formed by a single deposition process, or may have a multilayer structure formed by a plurality of deposition processes. In this case, the negative electrode active material may include a part having a multilayer structure as a part. However, in the case where high heat is accompanied during deposition, the negative electrode active material preferably has a multilayer structure in order to suppress the negative electrode current collector 1 from being thermally damaged. This is because when the negative electrode active material deposition step is performed in a plurality of times, the time during which the negative electrode current collector 1 is exposed to high heat is shorter than when the deposition step is performed once.

  The crystalline negative electrode active material is preferably alloyed at least at a part of the interface with the negative electrode current collector 1. This is because the negative electrode active material is less likely to expand and contract during the electrode reaction, and the negative electrode active material layer 2 is less likely to be damaged. Moreover, it is because electronic conductivity improves between the negative electrode collector 1 and the negative electrode active material. This “alloying” includes not only the case where the constituent element of the negative electrode current collector 1 and the constituent element of the negative electrode active material form a complete alloy, but also the case where both constituent elements are in a mixed state. . In this case, the constituent element of the negative electrode current collector 1 may be diffused into the negative electrode active material at the interface between them, or the constituent element of the negative electrode active material may be diffused into the negative electrode current collector 1. However, both constituent elements may be diffused.

  The crystalline negative electrode active material preferably has voids inside. This is because the voids act as a refuge (relaxation space) when the negative electrode active material expands and contracts during the electrode reaction, so that the negative electrode active material is less likely to expand and contract.

  In particular, the silicon iron-containing material that is the negative electrode active material preferably contains oxygen as a constituent element in addition to silicon and iron. This is because expansion and contraction of the negative electrode active material are suppressed during the electrode reaction. In this case, it is preferable that at least part of oxygen is bonded to part of silicon. The bonding state may be silicon monoxide or silicon dioxide, or another metastable state.

  Although oxygen content in a negative electrode active material is not specifically limited, Especially, it is preferable that they are 1.5 atomic% or more and 40 atomic% or less. This is because expansion and contraction of the negative electrode active material are suppressed while maintaining the performance of the negative electrode. Specifically, if the amount is less than 1.5 atomic percent, the negative electrode active material may not be sufficiently suppressed in expansion and contraction. If the amount is larger than 40 atomic percent, the resistance may increase excessively. . When the negative electrode is used in an electrochemical device together with an electrolyte, a film formed by a decomposition reaction of the electrolyte is not included in the negative electrode active material. That is, when the oxygen content in the negative electrode active material is calculated, oxygen in the above-described coating is not included.

  The negative electrode active material containing oxygen is formed, for example, by continuously introducing oxygen gas into the chamber when depositing the negative electrode material. In particular, when a desired oxygen content cannot be obtained simply by introducing oxygen gas, a liquid (for example, water vapor) may be introduced into the chamber as an oxygen supply source.

  The negative electrode active material preferably includes a high oxygen content region having a higher oxygen content and a low oxygen content region having a lower oxygen content in the thickness direction of the negative electrode active material layer 2. . This is because expansion and contraction of the negative electrode active material are suppressed during the electrode reaction. The oxygen content in the low oxygen content region is preferably as small as possible. The oxygen content in the high oxygen content region is not particularly limited, but is preferably the same as the oxygen content (1.5 atomic% to 40 atomic%) in the negative electrode active material.

  In this case, it is preferable that the high oxygen content region is sandwiched by the low oxygen content region, and it is more preferable that the low oxygen content region and the high oxygen content region are alternately laminated. This is because expansion and contraction of the negative electrode active material are further suppressed. When the low oxygen content region and the high oxygen content region are alternately laminated, the oxygen content is distributed while repeating high and low in the negative electrode active material.

  The negative electrode active material including the high oxygen content region and the low oxygen content region is, for example, intermittently introducing oxygen gas into the chamber or changing the amount of oxygen gas introduced into the chamber when depositing the negative electrode material. Formed. Of course, when a desired oxygen content cannot be obtained simply by introducing oxygen gas, a liquid (for example, water vapor) may be introduced into the chamber.

  Note that the oxygen content may or may not be clearly different between the high oxygen content region and the low oxygen content region. In particular, when the amount of oxygen gas introduced is continuously changed, the oxygen content may also be continuously changed. The high oxygen content region and the low oxygen content region are so-called “layers” when the oxygen gas introduction amount is changed intermittently, and “layers” when the oxygen gas introduction amount is continuously changed. Rather, it becomes “layered”. In this case, it is preferable that the oxygen content changes stepwise or continuously between the high oxygen content region and the low oxygen content region. This is because if the oxygen content changes rapidly, the diffusibility of ions may decrease or the resistance may increase.

  The negative electrode active material layer 2 may contain other negative electrode materials as long as the negative electrode material contains a silicon iron-containing material.

  Other negative electrode materials include, for example, materials that can occlude and release electrode reactants and contain at least one of a metal element and a metalloid element as a constituent element (corresponding to silicon iron-containing materials) Are excluded). This is because a high energy density can be obtained. Such a material may be a single element, an alloy or a compound of a metal element or a metalloid element, or may be two or more of them, or may have at least a part of one or more of those phases. . Note that “single substance” is a simple substance in a general sense, and does not necessarily mean 100% purity.

  The metal element or metalloid element described above is, for example, a metal element or metalloid element capable of forming an alloy with the electrode reactant, and specifically, at least one of the following elements. Magnesium, boron, aluminum, gallium, indium, germanium, tin, or lead (Pb). Further, bismuth, cadmium (Cd), silver, zinc, hafnium (Hf), zirconium, yttrium (Y), palladium (Pd), or platinum (Pt). Of these, tin is preferable. This is because a high energy density can be obtained because the ability to occlude and release the electrode reactant is excellent. The material containing tin may be a simple substance, an alloy or a compound of tin, or two or more thereof, or one having at least a part of one or two or more phases thereof.

  The “alloy” in the present invention includes one containing one or more metal elements and one or more metalloid elements in addition to one containing two or more metal elements. Of course, the “alloy” may contain a nonmetallic element. The structure includes solid solution, eutectic (eutectic mixture), intermetallic compound, or coexistence of two or more thereof.

Examples of the tin alloy include at least one of silicon, nickel, copper, iron, cobalt, manganese, zinc, indium, silver, titanium, germanium, bismuth, antimony, and chromium as constituent elements other than tin. Things. Examples of tin compounds include those containing oxygen or carbon as constituent elements other than tin. In addition, the compound of tin may contain any 1 type (s) or 2 or more types of the element demonstrated about the alloy of tin as structural elements other than tin, for example. Examples of tin alloys or compounds include SnSiO ₃ , LiSnO, Mg ₂ Sn, and the like.

  In particular, as a material containing tin, for example, a material containing tin as a first constituent element and further containing second and third constituent elements is preferable. This is because when the negative electrode is used in a secondary battery, a high battery capacity is obtained and cycle characteristics are improved. The second constituent element is, for example, at least one of the following elements. Cobalt, iron, magnesium, titanium, vanadium, chromium, manganese, nickel, copper, zinc, gallium or zirconium. Niobium, molybdenum, silver, indium, cerium (Ce), hafnium, tantalum, tungsten, bismuth, or silicon. The third constituent element is, for example, at least one of boron, carbon, aluminum, and phosphorus.

  Among these, a material containing Sn, cobalt, and carbon (SnCoC-containing material) is preferable. As the composition of this SnCoC-containing material, the carbon content is 9.9 mass% or more and 29.7 mass% or less, and the content ratio of tin and cobalt (Co / (Sn + Co)) is 20 mass% or more and 70 mass%. It is as follows. This is because a high energy density can be obtained in such a composition range. 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.

  This SnCoC-containing material has a phase containing tin, cobalt and carbon, and the phase is preferably low crystalline or amorphous. This phase is a reaction phase capable of reacting with the electrode reactant, and excellent characteristics can be obtained by the presence of the reaction phase. The half width of the diffraction peak obtained by X-ray diffraction of this phase is preferably 1 ° or more at a diffraction angle 2θ when CuKα ray is used as the specific X-ray and the drawing speed is 1 ° / min. . This is because the electrode reactant is occluded and released more smoothly, and the reactivity with the electrolyte and the like is further reduced. In addition to the low crystalline or amorphous phase, the SnCoC-containing material may have a phase containing a single element or a part of each constituent element.

  Note that the SnCoC-containing material may further contain other constituent elements as necessary. Examples of such other constituent elements include at least one of silicon, iron, nickel, chromium, indium, niobium, germanium, titanium, molybdenum, aluminum, phosphorus, gallium, and bismuth.

  In addition to this SnCoC-containing material, a material containing tin, cobalt, iron and carbon (SnCoFeC-containing material) is also preferable. The composition of the SnCoFeC-containing material can be arbitrarily set. For example, the composition when the content of iron is set to be small is as follows. The carbon content is 9.9 mass% or more and 29.7 mass% or less, the iron content is 0.3 mass% or more and 5.9 mass% or less, and the content ratio of tin and cobalt (Co / (Sn + Co)) ) Is 30% by mass or more and 70% by mass or less. For example, the composition in the case where the content of iron is set to be large is as follows. The carbon content is 11.9% by mass or more and 29.7% by mass or less. Further, the content ratio of tin, cobalt and iron ((Co + Fe) / (Sn + Co + Fe)) is 26.4 mass% to 48.5 mass%, and the content ratio of cobalt and iron (Co / (Co + Fe)). Is 9.9 mass% or more and 79.5 mass% or less. This is because a high energy density can be obtained in such a composition range. The physical properties and the like (half width, etc.) of this SnCoFeC-containing material are the same as those of the above-described SnCoC-containing material.

  Moreover, as another negative electrode material, a carbon material is mentioned, for example. This is because there is very little change in the crystal structure accompanying the insertion and extraction of the electrode reactant, and a high energy density can be obtained. Further, it also functions as a conductive agent. 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. Can be mentioned. More specifically, there are pyrolytic carbons, cokes, glassy carbon fibers, organic polymer compound fired bodies, activated carbon or carbon blacks. Of these, the cokes include pitch coke, needle coke, petroleum coke, and the like. The organic polymer compound fired body is obtained by firing and carbonizing a phenol resin, a furan resin, or the like at an appropriate temperature. The shape of the carbon material may be any of fibrous, spherical, granular or scale-like.

  Furthermore, examples of other negative electrode materials include metal oxides and polymer compounds. 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.

  Here, a detailed configuration example of the negative electrode will be described.

  2 and 3 show an enlarged part of the negative electrode shown in FIG. In each figure, (A) is a scanning electron microscope (SEM) photograph (secondary electron image), and (B) is a schematic picture of the SEM image shown in (A). 2 and 3 show a case where a silicon iron-containing material containing only silicon and iron is used as the negative electrode material.

  The negative electrode active material layer 2 is formed, for example, by depositing a negative electrode material on the surface of the negative electrode current collector 1 by a thermal spraying method or the like. In this case, the negative electrode active material layer 2 includes a plurality of crystalline negative electrode active materials (negative electrode active material particles 201) that are crystalline.

  The plurality of negative electrode active material particles 201 are connected to the surface of the negative electrode current collector 1. When the negative electrode current collector 1 is a roughened electrolytic copper foil or the like, the negative electrode material is formed so as to cover a plurality of protrusions (for example, fine particles) existing on the surface and to enter gaps between the protrusions. It is because it is deposited.

  The plurality of negative electrode active material particles 201 may have a single-layer structure arranged in a direction crossing the thickness direction of the negative electrode active material layer 2 or may have a multilayer structure stacked in the thickness direction. May be used, or both structures may be mixed.

  The negative electrode active material layer 2 has a plurality of voids 202 therein, for example. Moreover, since the negative electrode active material layer 2 is partially connected to the negative electrode current collector 1, for example, a portion where the negative electrode active material particles 201 are in contact with the negative electrode current collector 1 (contact portion P1) And a portion that is not in contact (non-contact portion P2).

  A part of the negative electrode active material particles 201 has a flat shape. That is, the plurality of negative electrode active material particles 201 include flat particles 201P. The flat particles 201P are in contact with the adjacent negative electrode active material particles 201 while overlapping.

[Production method of negative electrode]
This negative electrode is manufactured, for example, by the following procedure. First, a negative electrode current collector 1 made of a roughened electrolytic copper foil or the like is prepared. Subsequently, using a thermal spraying method or the like, a silicon iron-containing material is deposited on the surface of the negative electrode current collector 1 to form the negative electrode active material layer 2 containing a crystalline negative electrode active material. When using the thermal spraying method, a mixture of silicon and iron or the like may be used as a raw material, or a material in which silicon and iron are alloyed in advance by an atomizing method (alloy particles) may be used. Good. Thereby, the negative electrode is completed.

  According to this negative electrode, as a crystalline negative electrode active material capable of occluding and releasing an electrode reactant, a silicon iron-containing material (containing silicon and iron as constituent elements and having an iron content of 0.05 wt. % Material). In this case, the physical strength of the negative electrode active material is higher compared to the case where only silicon is contained and iron is not contained, or the case where iron is contained and the content is less than 0.05% by weight. And the resistance decreases. In addition, the negative electrode active material is less likely to expand and contract during the electrode reaction. Therefore, it can contribute to the performance improvement of the electrochemical device using a negative electrode. More specifically, when the negative electrode is used for a secondary battery, it can contribute to improvement of cycle characteristics.

  In particular, if the half width of the diffraction peak in the (111) crystal plane of the crystalline negative electrode active material obtained by X-ray diffraction is 20 ° or less, or the crystallite size resulting from the crystal plane is 100 nm or more, A higher effect can be obtained.

  Further, if the silicon iron-containing material, which is a crystalline negative electrode active material, contains an additional metal element such as aluminum as a constituent element, a higher effect can be obtained. In this case, a higher effect can be obtained if the total content of iron and additional metal elements is 0.2% by weight or more.

  Further, when the negative electrode active material contains oxygen and the oxygen content is 1.5 atomic% to 40 atomic%, higher effects can be obtained. Similarly, if the negative electrode active material has a high oxygen content region and a low oxygen content region, a higher effect can be obtained.

  Further, if the surface of the negative electrode current collector 1 is roughened, the adhesion of the negative electrode active material layer 2 to the negative electrode current collector 1 can be improved. In this case, a higher effect can be obtained if the ten-point average roughness Rz of the surface of the negative electrode current collector 1 is 1.5 μm or more, preferably 3 μm or more and 30 μm or less.

<2. Electrochemical device (secondary battery) using negative electrode>
Next, usage examples of the above-described negative electrode will be described. Here, taking a secondary battery as an example of an electrochemical device, the above-described negative electrode is used as follows.

<2-1. First secondary battery (square type)>
4 and 5 illustrate a cross-sectional configuration of the first secondary battery, and FIG. 5 illustrates a cross-section along the line VV illustrated in FIG. 4. The secondary battery described here is, for example, a lithium ion secondary battery in which the capacity of the negative electrode 22 is expressed by insertion and extraction of lithium ions that are electrode reactants.

[Overall structure of secondary battery]
In the secondary battery, a battery element 20 having a flat winding structure is mainly accommodated in a battery can 11.

  The battery can 11 is, for example, a square exterior member. As shown in FIG. 5, the square-shaped exterior member has a rectangular cross section or a substantially rectangular shape (including a curve in part) in the longitudinal direction. The shape is also included. That is, the square-shaped exterior member is a bottomed rectangular type or bottomed oval shaped vessel-like member having a rectangular shape or a substantially rectangular shape (oval shape) obtained by connecting arcs with straight lines. FIG. 5 shows a case where the battery can 11 has a rectangular cross-sectional shape. Such a battery structure using the battery can 11 is called a so-called square shape.

  The battery can 11 is made of, for example, iron, aluminum, or an alloy thereof, and may have a function as an electrode terminal. Among them, iron that is harder than aluminum is preferable in order to suppress battery swelling by utilizing the hardness (hardness of deformation) of the battery can 11 during charging and discharging. When the battery can 11 is made of iron, for example, the surface of the battery can 11 may be plated with nickel or the like.

  The battery can 11 has a hollow structure in which one end is opened and the other end is closed, and an insulating plate 12 and a battery lid 13 are attached to the open end to be sealed. The insulating plate 12 is disposed between the battery element 20 and the battery lid 13 so as to be perpendicular to the winding peripheral surface of the battery element 20, and is made of, for example, polypropylene. The battery lid 13 is made of, for example, the same material as that of the battery can 11 and may have a function as an electrode terminal.

  A terminal plate 14 serving as a positive terminal is provided outside the battery lid 13, and the terminal plate 14 is electrically insulated from the battery lid 13 through an insulating case 16. The insulating case 16 is made of, for example, polybutylene terephthalate. In addition, a through hole is provided in a substantially central portion of the battery lid 13, and the through hole is electrically connected to the terminal plate 14 and is electrically insulated from the battery lid 13 through the gasket 17. A positive electrode pin 15 is inserted as shown. The gasket 17 is made of, for example, an insulating material, and for example, asphalt is applied to the surface thereof.

  In the vicinity of the periphery of the battery lid 13, a cleavage valve 18 and an injection hole 19 are provided. The cleavage valve 18 is electrically connected to the battery lid 13, and is disconnected from the battery lid 13 to reduce the internal pressure when the internal pressure of the battery exceeds a certain level due to an internal short circuit or external heating. It is designed to be opened. The injection hole 19 is closed by a sealing member 19A made of, for example, a stainless steel ball.

  The battery element 20 is formed by laminating and winding a positive electrode 21 and a negative electrode 22 via a separator 23, and has a flat shape according to the shape of the battery can 11. A positive electrode lead 24 made of aluminum or the like is attached to an end portion (for example, an inner terminal portion) of the positive electrode 21, and a negative electrode lead 25 made of nickel or the like to an end portion (for example, the outer terminal portion) of the negative electrode 22. Is attached. The positive electrode lead 24 is welded to one end of the positive electrode pin 15 and is electrically connected to the terminal plate 14, and the negative electrode lead 25 is welded to and electrically connected to the battery can 11.

[Positive electrode]
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. 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, aluminum, nickel, stainless steel, or the like.

  The positive electrode active material layer 21B includes one or more positive electrode materials capable of inserting and extracting lithium ions as a positive electrode active material, and a positive electrode binder or a positive electrode as necessary. Other materials such as a conductive agent may be included.

As the positive electrode material, 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 containing lithium and a transition metal element as constituent elements, or a phosphate compound containing lithium and a transition metal element as constituent elements. Especially, what contains 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 containing lithium and a transition metal element include lithium cobalt composite oxide (Li _x CoO ₂ ), lithium nickel composite oxide (Li _x NiO ₂ ), or lithium represented by the formula (12). Examples include nickel-based composite oxides. Examples of the phosphate compound containing 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. This is because high battery capacity is obtained and excellent cycle characteristics are also obtained.

LiNi _1-x M _x O ₂ (12)
(M is cobalt, manganese, iron, aluminum, vanadium, tin, magnesium, titanium, strontium, calcium, zirconium, molybdenum, technetium, ruthenium, tantalum, tungsten, rhenium, ytterbium, copper, zinc, barium, boron, chromium, silicon And at least one of gallium, phosphorus, antimony, and niobium, and x is 0.005 <x <0.5.)

  In addition, examples of the positive electrode material include oxides, disulfides, chalcogenides, and conductive polymers. Examples of the oxide include titanium oxide, vanadium oxide, and manganese dioxide. Examples of the disulfide include titanium disulfide and molybdenum sulfide. An example of the chalcogenide is niobium selenide. Examples of the conductive polymer include sulfur, polyaniline, and polythiophene.

  Of course, the positive electrode material 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 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.

  Examples of the positive electrode conductive agent include carbon materials such as graphite, carbon black, acetylene black, and ketjen black. These may be single and multiple types may be mixed. The positive electrode conductive agent may be a metal material or a conductive polymer as long as it is a conductive material.

[Negative electrode]
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 configurations of the negative electrode current collector 22A and the negative electrode active material layer 22B are the same as the configurations of the negative electrode current collector 1 and the negative electrode active material layer 2 in the above-described negative electrode, respectively. That is, the negative electrode active material layer 22B contains a silicon iron-containing material as a negative electrode active material. In this case, as described above, the iron content is not particularly limited as long as it is 0.05% by weight or more. However, in order to prevent the battery capacity from being excessively decreased due to too much iron content. 0.05 wt% or more and 8.8 wt% or less is preferable. In this negative electrode 22, the chargeable capacity of the negative electrode material capable of inserting and extracting lithium ions is preferably larger than the discharge capacity of the positive electrode 21. This is to prevent unintentional precipitation of lithium metal during charging.

[Separator]
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 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, or a porous film made of ceramic. The separator 23 may be a laminate of two or more porous films.

[Electrolytes]
The separator 23 is impregnated with an electrolytic solution that is a liquid electrolyte. This electrolytic solution is obtained by dissolving an electrolyte salt in a solvent, and may contain other materials such as various additives as necessary.

  The solvent contains, for example, one or more of nonaqueous solvents such as organic solvents. A series of solvents (nonaqueous solvent) described below may be used alone or in combination of two or more.

  Examples of the non-aqueous solvent include the following. Ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, methyl propyl carbonate, γ-butyrolactone, γ-valerolactone, 1,2-dimethoxyethane or tetrahydrofuran. Also, 2-methyltetrahydrofuran, tetrahydropyran, 1,3-dioxolane, 4-methyl-1,3-dioxolane, 1,3-dioxane, or 1,4-dioxane. Further, methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, methyl butyrate, methyl isobutyrate, methyl trimethyl acetate or ethyl trimethyl acetate. Acetonitrile, glutaronitrile, adiponitrile, methoxyacetonitrile, 3-methoxypropionitrile, N, N-dimethylformamide, N-methylpyrrolidinone or N-methyloxazolidinone. Further, N, N'-dimethylimidazolidinone, nitromethane, nitroethane, sulfolane, trimethyl phosphate or dimethyl sulfoxide. This is because excellent battery capacity, cycle characteristics, storage characteristics, and the like can be obtained.

  Among these, at least one of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate is preferable. This is because excellent battery capacity, cycle characteristics, storage characteristics, and the like can be obtained. 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 mPas). -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 preferably contains at least one of a halogenated chain carbonate represented by the formula (1) and a halogenated cyclic carbonate represented by the formula (2). This is because a stable protective film is formed on the surface of the negative electrode 22 at the time of charge and discharge, so that the decomposition reaction of the electrolytic solution is suppressed. The “halogenated chain carbonate ester” is a chain carbonate ester containing halogen as a constituent element, and the “halogenated cyclic carbonate ester” is a cyclic carbonate ester containing halogen as a constituent element. In addition, R11-R16 in Formula (1) may be the same, and may differ. The same applies to R17 to R20 in the formula (2). The content of the halogenated chain carbonate and the halogenated cyclic carbonate in the solvent is, for example, 0.01 wt% to 50 wt%.

（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.)

  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 an effect higher than that of other halogens can be obtained. 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 halogenated chain carbonate include fluoromethyl methyl carbonate, bis (fluoromethyl) carbonate, difluoromethyl methyl carbonate, and the like.

  Examples of the halogenated cyclic carbonate include compounds represented by Formula (2-1) to Formula (2-21). This halogenated cyclic carbonate includes geometric isomers.

  Among them, 4-fluoro-1,3-dioxolan-2-one represented by the formula (2-1) or 4,5-difluoro-1,3-dioxolan-2-one represented by the formula (2-3) is preferable. The latter is preferred and the latter is 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 unsaturated carbon bond cyclic carbonate represented by Formula (3)-Formula (5). This is because a stable protective film is formed on the surface of the negative electrode 22 at the time of charge and discharge, so that the decomposition reaction of the electrolytic solution is suppressed. The “unsaturated carbon bond cyclic carbonate” is a cyclic carbonate having an unsaturated bond. The unsaturated carbon bond cyclic ester carbonate also includes geometric isomers. The content of the unsaturated carbon bond cyclic carbonate in the solvent is, for example, 0.01% by weight to 10% by weight.

（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 unsaturated carbon bond cyclic ester carbonate shown in Formula (3) is a vinylene carbonate compound. Examples of the vinylene carbonate-based compound include the following. Vinylene carbonate (1,3-dioxol-2-one), methyl vinylene carbonate (4-methyl-1,3-dioxol-2-one) or 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-1,3-dioxol-2-one or 4- Trifluoromethyl-1,3-dioxol-2-one. Among these, vinylene carbonate is preferable. This is because it is easily available and a high effect can be obtained.

  The unsaturated carbon bond cyclic carbonate represented by the formula (4) is a vinyl ethylene carbonate compound. Examples of the vinyl carbonate-based compound include the following. Vinyl ethylene carbonate (4-vinyl-1,3-dioxolan-2-one), 4-methyl-4-vinyl-1,3-dioxolan-2-one or 4-ethyl-4-vinyl-1,3-dioxolane -2-one. Further, 4-n-propyl-4-vinyl-1,3-dioxolan-2-one, 5-methyl-4-vinyl-1,3-dioxolan-2-one, 4,4-divinyl-1,3- Dioxolan-2-one or 4,5-divinyl-1,3-dioxolan-2-one. Of these, vinyl ethylene carbonate is preferred. 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 unsaturated carbon bond cyclic carbonate represented by the formula (5) is a methylene ethylene carbonate compound. Examples of the methylene ethylene carbonate compound include the following. 4-methylene-1,3-dioxolan-2-one, 4,4-dimethyl-5-methylene-1,3-dioxolan-2-one or 4,4-diethyl-5-methylene-1,3-dioxolane- 2-one. 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 (5)).

  In addition, as unsaturated carbon bond cyclic carbonate ester, the catechol carbonate (catechol carbonate) etc. which have a benzene ring other than what was shown to Formula (3)-Formula (5) may be sufficient.

  Moreover, it is preferable that the solvent contains sultone (cyclic sulfonate ester). This is because the chemical stability of the electrolytic solution is improved. Examples of sultone include propane sultone and propene sultone. 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 improved. Examples of the acid anhydride include carboxylic acid anhydride, disulfonic acid anhydride, carboxylic acid sulfonic acid anhydride, and the like. Examples of the carboxylic acid anhydride include succinic anhydride, glutaric anhydride, and maleic anhydride. Examples of the disulfonic anhydride include ethane disulfonic anhydride and propane disulfonic anhydride. Examples of the carboxylic acid sulfonic anhydride include anhydrous sulfobenzoic acid, anhydrous sulfopropionic acid, and anhydrous sulfobutyric acid. 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 includes, for example, any one or more of light metal salts such as lithium salts. The series of electrolyte salts described below may be used alone or in combination of two or more.

Examples of the lithium salt include the following. Lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate or lithium hexafluoroarsenate. Further, lithium tetraphenylborate (LiB (C ₆ H ₅ ) ₄ ), lithium methanesulfonate (LiCH ₃ SO ₃ ), lithium trifluoromethanesulfonate (LiCF ₃ SO ₃ ) or lithium tetrachloroaluminate (LiAlCl ₄ ) It is. Further, dilithium hexafluorosilicate (Li ₂ SiF ₆ ), lithium chloride (LiCl) or lithium bromide (LiBr). This is because excellent battery capacity, cycle characteristics, storage characteristics, and the like can be obtained.

  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 (6) to (8). This is because a higher effect can be obtained. In addition, R31 and R33 of Formula (6) may be the same or different. The same applies to R41 to R43 in formula (7) and R51 and R52 in formula (8).

（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, and at least one of each is 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 the formula (6) include compounds represented by the formula (6-1) to the formula (6-6). Examples of the compound represented by formula (7) include compounds represented by formula (7-1) to formula (7-8). Examples of the compound represented by the formula (8) include a compound represented by the formula (8-1).

  Moreover, it is preferable that electrolyte salt contains at least 1 sort (s) of the compounds represented by Formula (9)-Formula (11). This is because a higher effect can be obtained. In addition, m and n in Formula (9) may be the same or different. The same applies to p, q and r in the formula (11).

_{LiN (C m F 2m + 1} SO 2) (C n F 2n + 1 SO 2) ... (9)
(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.)

LiC (C _p F _{2p + 1} SO ₂ ) (C _q F _{2q + 1} SO ₂ ) (C _r F _{2r + 1} SO ₂ ) (11)
(P, q and r are integers of 1 or more.)

The compound shown in Formula (9) is a chain imide compound. Examples of such compounds include the following. Bis (trifluoromethanesulfonyl) imide lithium (LiN (CF ₃ SO ₂ ) ₂ ) or bis (pentafluoroethanesulfonyl) imide lithium (LiN (C ₂ F ₅ SO ₂ ) ₂ ). Further, it is (trifluoromethanesulfonyl) (pentafluoroethanesulfonyl) imidolithium (LiN (CF ₃ SO ₂ ) (C ₂ F ₅ SO ₂ )). Further, it is (trifluoromethanesulfonyl) (heptafluoropropanesulfonyl) imidolithium (LiN (CF ₃ SO ₂ ) (C ₃ F ₇ SO ₂ )). Further, (trifluoromethanesulfonyl) (nonafluorobutanesulfonyl) imidolithium (LiN (CF ₃ SO ₂ ) (C ₄ F ₉ SO ₂ )).

  The compound shown in Formula (10) is a cyclic imide compound. Examples of such a compound include compounds represented by formula (10-1) to formula (10-4).

The compound represented by the formula (11) is a chain methide compound. Examples of such a compound 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 high ionic conductivity is obtained.

[Operation of secondary battery]
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.

[Method for producing secondary battery]
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, a positive electrode conductive agent, and the like are mixed to obtain a positive electrode mixture, and then dispersed in an organic solvent to obtain a paste-like positive electrode mixture slurry. Subsequently, the positive electrode mixture slurry is uniformly applied to both surfaces of the positive electrode current collector 21A using a doctor blade or a bar coater, and then dried to form the positive electrode 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 manufactured according to the negative electrode manufacturing procedure described above. In this case, a negative electrode active material layer 22B containing a crystalline negative electrode active material is formed by depositing a silicon iron-containing material as a negative electrode material on both surfaces of the negative electrode current collector 22A using a thermal spraying method or the like.

  The secondary battery is assembled as follows. First, after storing the battery element 20 in the battery can 11, the insulating plate 12 is disposed on the battery element 20. Subsequently, the positive electrode lead 24 is attached to the positive electrode pin 15 by welding or the like, and the negative electrode lead 25 is attached to the battery can 11 by welding or the like, and then the battery lid is attached to the open end of the battery can 11 by laser welding or the like. 13 is fixed. Finally, after injecting the electrolyte into the battery can 11 from the injection hole 19 and impregnating the separator 23, the injection hole 19 is closed with a sealing member 19A. Thereby, the secondary battery shown in FIGS. 4 and 5 is completed.

  According to the first secondary battery, the negative electrode 22 has the same configuration as the negative electrode described above. For this reason, the physical strength of the negative electrode active material layer 22B increases and the resistance decreases. In addition, the negative electrode active material layer 22B is less likely to expand and contract during charging and discharging. Therefore, cycle characteristics can be improved.

  In particular, if the solvent of the electrolytic solution contains at least one of halogenated chain carbonate, halogenated cyclic carbonate, unsaturated carbon bond cyclic carbonate, sultone, and acid anhydride, cycle characteristics are further improved. Can be made.

  Moreover, electrolyte salt of electrolyte solution is lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, and the compound shown in Formula (6)-Formula (11) If at least one kind is included, cycle characteristics can be further improved.

<2-2. Second secondary battery (cylindrical type)>
6 and 7 show a cross-sectional configuration of the second secondary battery, and FIG. 7 shows an enlarged part of the spirally wound electrode body 40 shown in FIG.

  This secondary battery is a lithium ion secondary battery as in the case of the first secondary battery, and mainly includes a wound electrode body 40 and a pair of insulating plates 32 inside a substantially hollow cylindrical battery can 31. , 33 are stored. A battery structure using such a battery can 31 is called a cylindrical type.

  The battery can 31 is made of, for example, the same material as that of the battery can 11 in the first secondary battery. One end of the battery can 31 is open and the other end is closed. The pair of insulating plates 32 and 33 are arranged so as to sandwich the wound electrode body 40 from above and below and to extend perpendicular to the wound peripheral surface.

  A battery lid 34, a safety valve mechanism 35 and a heat sensitive resistance element (Positive Temperature Coefficient: PTC element) 36 provided inside thereof are caulked through a gasket 37 at the open end of the battery can 31. By this caulking, the inside of the battery can 31 is sealed. The battery lid 34 is made of, for example, the same material as the battery can 31. The safety valve mechanism 35 is electrically connected to the battery lid 34 via the heat sensitive resistance element 36. In the safety valve mechanism 35, when the internal pressure becomes a certain level or more due to an internal short circuit or external heating, the disk plate 35A is reversed and the electric power between the battery lid 34 and the wound electrode body 40 is reversed. Connection is cut off. The thermosensitive element 36 limits the current by increasing the resistance in response to the temperature rise, and prevents abnormal heat generation due to a large current. The gasket 37 is made of, for example, an insulating material, and for example, asphalt is applied to the surface thereof.

  The wound electrode body 40 is obtained by laminating and winding a positive electrode 41 and a negative electrode 42 with a separator 43 interposed therebetween. For example, a center pin 44 may be inserted in the center of the wound electrode body 40. In this wound electrode body 40, a positive electrode lead 45 made of aluminum or the like is connected to the positive electrode 41, and a negative electrode lead 46 made of nickel or the like is connected to the negative electrode 42. The positive electrode lead 45 is welded to the safety valve mechanism 35 and electrically connected to the battery lid 34, and the negative electrode lead 46 is welded to the battery can 31 and electrically connected thereto.

  In the positive electrode 41, for example, a positive electrode active material layer 41B is provided on both surfaces of a positive electrode current collector 41A. The configurations of the positive electrode current collector 41A and the positive electrode active material layer 41B are the same as the configurations of the positive electrode current collector 21A and the positive electrode active material layer 21B in the first secondary battery, respectively.

  In the negative electrode 42, for example, a negative electrode active material layer 42B is provided on both surfaces of a negative electrode current collector 42A. The configurations of the negative electrode current collector 42A and the negative electrode active material layer 42B are the same as the configurations of the negative electrode current collector 22A and the negative electrode active material layer 22B in the first secondary battery, respectively. That is, the negative electrode active material layer 42B includes a silicon iron-containing material as a negative electrode active material.

  The configuration of the separator 43 and the composition of the electrolytic solution are the same as the configuration of the separator 23 and the composition of the electrolytic solution in the first secondary battery, respectively.

  In this secondary battery, at the time of charging, for example, lithium ions are released from the positive electrode 41 and inserted in the negative electrode 42 through the electrolytic solution. On the other hand, at the time of discharge, for example, lithium ions are released from the negative electrode 42 and inserted in the positive electrode 41 through the electrolytic solution.

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

  First, according to the same procedure as the positive electrode 21 and the negative electrode 22 in the first secondary battery, the positive electrode active material layer 41B is formed on both surfaces of the positive electrode current collector 41A to produce the positive electrode 41, and the negative electrode current collector 42A The negative electrode 42 is fabricated by forming the negative electrode active material layer 42B on both sides. Subsequently, the positive electrode lead 45 is attached to the positive electrode 41 by welding or the like, and the negative electrode lead 46 is attached to the negative electrode 42 by welding or the like. Subsequently, the positive electrode 41 and the negative electrode 42 are stacked and wound through the separator 43 to produce the wound electrode body 40, and then the center pin 44 is inserted into the winding center. Subsequently, the wound electrode body 40 is accommodated in the battery can 31 while being sandwiched between the pair of insulating plates 32 and 33. In this case, the tip of the positive electrode lead 45 is welded to the safety valve mechanism 35 and the tip of the negative electrode lead 46 is welded to the battery can 31. Subsequently, an electrolytic solution is injected into the battery can 31 and impregnated in the separator 43. Finally, the battery lid 34, the safety valve mechanism 35, and the heat sensitive resistance element 36 are caulked to the opening end of the battery can 31 via the gasket 37. Thereby, the secondary battery shown in FIGS. 6 and 7 is completed.

  According to the second secondary battery, since the negative electrode 42 has the same configuration as the above-described negative electrode, the cycle characteristics can be improved by the same action as the first secondary battery. Other effects relating to the secondary battery are the same as those of the first secondary battery.

<2-3. Third Secondary Battery (Laminated Film Type)>
FIG. 8 shows an exploded perspective configuration of the third secondary battery, and FIG. 9 shows an enlarged cross section taken along line IX-IX of the spirally wound electrode body 50 shown in FIG.

  This secondary battery is a lithium ion secondary battery, like the first secondary battery, and is mainly a wound electrode in which a positive electrode lead 51 and a negative electrode lead 52 are attached inside a film-like exterior member 60. The body 50 is stored. A battery structure using such an exterior member 60 is called a laminate film type.

  The positive electrode lead 51 and the negative electrode lead 52 are led out in the same direction from the inside of the exterior member 60 to the outside, for example. However, the installation position of the positive electrode lead 51 and the negative electrode lead 52 with respect to the spirally wound electrode body 50 and the direction in which they are derived are not particularly limited. The positive electrode lead 51 is made of, for example, aluminum, and the negative electrode lead 52 is made of, for example, copper, nickel, stainless steel, or the like. These materials have, for example, a thin plate shape or a mesh shape.

  The exterior member 60 is, for example, a laminate film in which a fusion layer, a metal layer, and a surface protective layer are laminated in this order. In this case, for example, the outer edges of the fusion layers of the two films are bonded to each other with an adhesive or the like so that the fusion layer faces the wound electrode body 50. Examples of the fusion layer include a film of polyethylene or polypropylene. Examples of the metal layer include aluminum foil. Examples of the surface protective layer include films of nylon or polyethylene terephthalate.

  Especially, as the exterior member 60, an aluminum laminated film in which a polyethylene film, an aluminum foil, and a nylon film are laminated in this order is preferable. However, the exterior member 60 may be a laminated film having another laminated structure instead of the aluminum laminated film, or may be a polymer film such as polypropylene or a metal film.

  An adhesion film 61 is inserted between the exterior member 60 and the positive electrode lead 51 and the negative electrode lead 52 to prevent the outside air from entering. The adhesion film 61 is made of a material having adhesion to the positive electrode lead 51 and the negative electrode lead 52. Examples of such a material include polyolefin resins such as polyethylene, polypropylene, modified polyethylene, and modified polypropylene.

  The wound electrode body 50 is obtained by laminating and winding a positive electrode 53 and a negative electrode 54 via a separator 55 and an electrolyte layer 56, and the outermost peripheral portion thereof is protected by a protective tape 57.

  In the positive electrode 53, for example, the positive electrode active material layer 53B is provided on both surfaces of the positive electrode current collector 53A. The configurations of the positive electrode current collector 53A and the positive electrode active material layer 53B are the same as those of the positive electrode current collector 21A and the positive electrode active material layer 21B in the first secondary battery, respectively.

  In the negative electrode 54, for example, a negative electrode active material layer 54B is provided on both surfaces of a negative electrode current collector 54A. The configurations of the negative electrode current collector 54A and the negative electrode active material layer 54B are the same as the configurations of the negative electrode current collector 22A and the negative electrode active material layer 22B in the first secondary battery, respectively. That is, the negative electrode active material layer 54B includes a silicon iron-containing material as a negative electrode active material.

  The configuration of the separator 55 is the same as the configuration of the separator 23 in the first secondary battery.

  The electrolyte layer 56 is one in which an electrolytic solution is held by a polymer compound, and may contain other materials such as various additives as necessary. The electrolyte layer 56 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 leakage of the electrolyte is prevented.

  Examples of the polymer compound include the following. Polyacrylonitrile, polyvinylidene fluoride, polytetrafluoroethylene, polyhexafluoropropylene, polyethylene oxide, polypropylene oxide, polyphosphazene, polysiloxane, or polyvinyl fluoride. Polyvinyl acetate, polyvinyl alcohol, polymethyl methacrylate, polyacrylic acid, polymethacrylic acid, styrene-butadiene rubber, nitrile-butadiene rubber, polystyrene or polycarbonate. Further, it is a copolymer of vinylidene fluoride and hexafluoropyrene. These may be single and multiple types may be mixed. Among these, polyvinylidene fluoride or a copolymer of vinylidene fluoride and hexafluoropyrene 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. However, in the electrolyte layer 56 which is a gel electrolyte, the solvent of the electrolytic solution is a wide concept including not only a liquid solvent but also a material having ion conductivity capable of dissociating the electrolyte salt. Therefore, when using a polymer compound having ion conductivity, the polymer compound is also included in the solvent.

  Instead of the gel electrolyte layer 56 in which the electrolyte is held by the polymer compound, the electrolyte may be used as it is. In this case, the separator 55 is impregnated with the electrolytic solution.

  In this secondary battery, during charging, for example, lithium ions are released from the positive electrode 53 and inserted into the negative electrode 54 via the electrolyte layer 56. On the other hand, at the time of discharging, for example, lithium ions are released from the negative electrode 54 and inserted in the positive electrode 53 through the electrolyte layer 56.

  The secondary battery provided with the gel electrolyte layer 56 is manufactured by, for example, the following three types of procedures.

  In the first manufacturing method, first, the positive electrode 53 and the negative electrode 54 are manufactured by the same manufacturing procedure as that of the positive electrode 21 and the negative electrode 22 in the first secondary battery. Specifically, the positive electrode active material layer 53B is formed on both surfaces of the positive electrode current collector 53A to produce the positive electrode 53, and the negative electrode active material layer 54B is formed on both surfaces of the negative electrode current collector 54A to produce the negative electrode 54. To do. Then, after preparing the precursor solution containing electrolyte solution, a high molecular compound, and a solvent and apply | coating to the positive electrode 53 and the negative electrode 54, the solvent is volatilized and the gel electrolyte layer 56 is formed. Subsequently, the positive electrode lead 51 is attached to the positive electrode current collector 53A by welding or the like, and the negative electrode lead 52 is attached to the negative electrode current collector 54A by welding or the like. Subsequently, the positive electrode 53 and the negative electrode 54 on which the electrolyte layer 56 is formed are stacked and wound via a separator 55, and then a protective tape 57 is adhered to the outermost peripheral portion thereof to produce the wound electrode body 50. . Finally, after sandwiching the wound electrode body 50 between the two film-shaped exterior members 60, the outer edges of the exterior member 60 are bonded to each other by heat fusion or the like, and the wound electrode body 50 is enclosed. To do. At this time, the adhesion film 61 is inserted between the positive electrode lead 51 and the negative electrode lead 52 and the exterior member 60. Thereby, the secondary battery shown in FIGS. 8 and 9 is completed.

  In the second manufacturing method, first, the positive electrode lead 51 is attached to the positive electrode 53 and the negative electrode lead 52 is attached to the negative electrode 54. Subsequently, after the positive electrode 53 and the negative electrode 54 are laminated and wound via the separator 55, a protective tape 57 is adhered to the outermost periphery thereof, and a wound body that is a precursor of the wound electrode body 50. Is made. Subsequently, after sandwiching the wound body between the two film-like exterior members 60, the remaining outer peripheral edge portion excluding the outer peripheral edge portion on one side is adhered by heat fusion or the like, and the bag-shaped exterior The wound body is accommodated in the member 60. 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-like exterior After the injection into the member 60, the opening of the exterior member 60 is sealed by heat sealing or the like. Finally, the monomer is thermally polymerized to obtain a polymer compound, and the gel electrolyte layer 56 is formed. 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 the above-described second manufacturing method, except that the separator 55 coated with the polymer compound on both sides is used first. 60 is housed inside. Examples of the polymer compound applied to the separator 55 include a polymer (such as a homopolymer, a copolymer, or a multi-component copolymer) containing vinylidene fluoride as a component. Specifically, polyvinylidene fluoride, a binary copolymer containing vinylidene fluoride and hexafluoropropylene as components, and a ternary copolymer 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 60, the opening of the exterior member 60 is sealed by thermal fusion or the like. Finally, the exterior member 60 is heated while applying a load, and the separator 55 is brought into close contact with the positive electrode 53 and the negative electrode 54 through the polymer compound. Thereby, the electrolytic solution is impregnated into the polymer compound, and the polymer compound is gelled to form the electrolyte layer 56, whereby the secondary battery is completed.

  In the third manufacturing method, battery swelling is suppressed more than in the first manufacturing method. In the third manufacturing method, the monomer or solvent that is a raw material of the polymer compound is hardly left in the electrolyte layer 56 and the formation process of the polymer compound is controlled better than in the second manufacturing method. The For this reason, sufficient adhesion is obtained between the positive electrode 53, the negative electrode 54 and the separator 55 and the electrolyte layer 56.

  According to the third secondary battery, since the negative electrode 54 has the same configuration as the above-described negative electrode, the cycle characteristics can be improved by the same action as the first secondary battery. Other effects relating to the secondary battery are the same as those of the first secondary battery.

  Examples of the present invention will be described in detail.

(Experimental Examples 1-1 to 1-15)
The laminate film type lithium ion secondary battery shown in FIGS. 8 and 9 was produced by the following procedure.

  First, the positive electrode active material layer 53B was formed on the positive electrode current collector 53A using a coating method, and the positive electrode 53 was manufactured.

In this case, lithium carbonate (Li ₂ CO ₃ ) and cobalt carbonate (CoCO ₃ ) are first mixed at a molar ratio of 0.5: 1, and then calcined in air at 900 ° C. for 5 hours. A cobalt composite oxide (LiCoO ₂ ) was obtained. Subsequently, 91 parts by mass of LiCoO ₂ 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 were mixed to obtain a positive electrode mixture. Subsequently, the positive electrode mixture was dispersed in N-methyl-2-pyrrolidone to obtain a paste-like positive electrode mixture slurry. Subsequently, the positive electrode mixture slurry was uniformly applied to both surfaces of the positive electrode current collector 53A using a coating apparatus, and then dried to form the positive electrode active material layer 53B. As the positive electrode current collector 53A, a strip-shaped aluminum foil (thickness = 12 μm) was used. Finally, the positive electrode active material layer 53B was compression molded using a roll press.

  Next, the negative electrode active material layer 54B was formed on the negative electrode current collector 54A by using a thermal spraying method (gas flame spraying method), so that the negative electrode 54 was manufactured.

  In this case, first, a silicon iron-containing material having the composition shown in Table 1 was prepared as the negative electrode material. As the silicon-iron-containing material, a material obtained by alloying a pulverized product of single crystal silicon (purity = 99.99%) and iron (purity = 99.9%) using a gas atomization method was used. At this time, the ratio (weight ratio) of silicon and iron was changed as shown in Table 1. Subsequently, a negative electrode material (median diameter = 1 μm to 300 μm) is sprayed on the surface of the negative electrode current collector 54A in a molten state or a semi-molten state, and a negative electrode active material containing a crystalline negative electrode active material (a plurality of negative electrode active material particles) is obtained. A material layer 54B was formed. As the negative electrode current collector 54A, a strip-shaped electrolytic copper foil (thickness = 15 μm, surface ten-point average roughness Rz = 3 μm) was used. In the thermal spraying process, oxygen gas and hydrogen gas were used as the gas for generating the thermal spray flame, nitrogen gas was used as the gas for spraying the negative electrode material, and the spraying speed was about 45 m / second to 55 m / second. At this time, a spraying process was performed while cooling the substrate with carbon dioxide gas so that the negative electrode current collector 54A was not thermally damaged.

  In particular, when forming the negative electrode active material layer 54B, oxygen gas was continuously blown to the thermal spray flame so that the oxygen content in the negative electrode active material was 5 atomic%. Further, the median diameter and the melting temperature of the negative electrode material were adjusted so that the plurality of negative electrode active material particles contained flat particles. Furthermore, by adjusting the melting temperature of the negative electrode material and the cooling temperature of the substrate, the half-value width (2θ) of the diffraction peak in the (111) crystal plane of the negative electrode active material obtained by X-ray diffraction is 1 °, resulting from the same crystal plane The crystallite size to be set was 350 nm. In addition, when performing X-ray diffraction analysis, the X-ray diffraction apparatus by Rigaku Electric Co., Ltd. was used. At this time, CuKa was used as the government ball, the government voltage was 40 kV, the government current was 40 mA, the scan method was the θ-2θ method, and the measurement range was 20 ° ≦ 2θ ≦ 90 °.

Next, after mixing ethylene carbonate (EC) and diethyl carbonate (DEC) as a solvent, lithium hexafluorophosphate (LiPF ₆ ) was dissolved as an electrolyte salt to prepare an electrolytic solution that is a liquid electrolyte. . 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.

  Finally, a secondary battery was assembled using the electrolytic solution together with the positive electrode 53 and the negative electrode 54. First, the positive electrode lead 51 made of aluminum was welded to one end of the positive electrode current collector 53A, and the negative electrode lead 52 made of nickel was welded to one end of the negative electrode current collector 54A. Subsequently, after the positive electrode 53, the separator 55, the negative electrode 54, and the separator 55 are laminated in this order and wound in the longitudinal direction, the winding end portion is fixed with the protective tape 57 made of an adhesive tape, A wound body that is a precursor of the wound electrode body 50 was formed. As the separator 55, a three-layer structure (thickness = 23 μm) in which a film mainly composed of porous polyethylene was sandwiched between films mainly composed of porous polypropylene. Subsequently, after the wound body was sandwiched between the exterior members 60, the outer edge portions except for one side were heat-sealed, and the wound body was accommodated in the bag-shaped exterior member 60. As the exterior member 60, a laminate having a three-layer structure 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 film (total thickness = 100 μm) was used. Subsequently, an electrolytic solution was injected from the opening of the exterior member 60 and impregnated in the separator 55, thereby manufacturing the wound electrode body 50. Finally, the laminated film type secondary battery was completed by thermally sealing and sealing the opening of the exterior member 60 in a vacuum atmosphere. In the production of this secondary battery, the thickness of the positive electrode active material layer 53B was adjusted so that lithium metal did not deposit on the negative electrode 54 during full charge.

(Experimental Example 1-16)
The same procedure as in Experimental Examples 1-1 to 1-15 was performed, except that silicon alone (purity = 99.99%) was used as the negative electrode material.

(Experimental Examples 1-17 to 1-19)
Except that an amorphous negative electrode active material made of a silicon iron-containing material was formed using a vapor deposition method (electron beam vapor deposition method), the same procedures as in Experimental Examples 1-5, 1-9, and 1-16 were performed. . In the vapor deposition step, a silicon simple substance or alloy shown in Table 1 was used as a deflection electron beam vapor deposition source, and the deposition rate was set to 100 nm / second. In addition, oxygen gas and water vapor as necessary were continuously introduced into the chamber, so that the oxygen content in the amorphous negative electrode active material was 5 atomic%.

  When the cycle characteristics of the secondary batteries of Examples 1-1 to 1-19 were examined, the results shown in Table 1 and FIG. 10 were obtained.

In examining the cycle characteristics, first, in order to stabilize the battery state, the battery was charged and discharged for one cycle in an atmosphere at 23 ° C., and then charged and discharged again, and the discharge capacity at the second cycle was measured. Subsequently, 99 cycles were charged and discharged in the same atmosphere, and the discharge capacity at the 101st cycle was measured. Finally, discharge capacity retention ratio (%) = (discharge capacity at the 101st cycle / discharge capacity at the second cycle) × 100 was calculated. In this case, charging was performed at a constant current density of 3 mA / cm ² until the battery voltage reached 4.2 V, and then charging was performed at a constant voltage of 4.2 V until the current density reached 0.3 mA / cm ² . . 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 are the same in the following series of experimental examples.

  When the crystalline negative electrode active material was formed using the thermal spraying method, the discharge capacity retention rate was higher than when the amorphous negative electrode active material was formed using the vapor deposition method. In addition, when the crystalline negative electrode active material was formed, the discharge capacity retention rate was higher when the silicon iron-containing material was used than when the silicon simple substance was used. In this case, a high discharge capacity retention rate was obtained when the iron content was 0.05% by weight or more. For these reasons, in the secondary battery of the present invention, the cycle characteristics are improved by using a silicon iron-containing material having an iron content of 0.05% by weight or more as the negative electrode active material.

(Experimental examples 2-1 to 2-38)
As shown in Tables 2 to 5, the same procedure as in Experimental Examples 1-1 to 1-19 was performed except that the silicon iron-containing material contained an additional metal element such as aluminum. When the cycle characteristics of the secondary batteries of Experimental Examples 2-1 to 2-38 were examined, the results shown in Tables 2 to 5 were obtained.

  Even when the silicon iron-containing material contains an additional metal element, the same results as in Table 1 were obtained. In this case, when the additional metal element was included, the discharge capacity retention rate was higher than when the additional metal element was not included. Further, as is apparent from a comparison between SiFe (Experimental 1-3) and SiFeAlCa (Experimental 2-11), when an additional metal element is included, the total content of iron and the additional metal element is 0. When it was 2% by weight or more, the discharge capacity retention rate was higher. For these reasons, in the secondary battery of the present invention, if the silicon iron-containing material contains an additional metal element, the cycle characteristics are further improved. In this case, if the total content of iron and additional metal elements is 0.2% by weight or more, the cycle characteristics are further improved.

(Experimental examples 3-1 to 3-5)
Except that the negative electrode active material layer 54B was formed using a coating method, the same procedure as in Experimental Examples 1-1 to 1-15 was performed. In the case of forming the negative electrode active material layer 54B, first, as a negative electrode active material, silicon powder (median diameter = 1 μm to 40 μm) and a polyamic acid solution are mixed at a dry weight ratio of 80:20 to form a negative electrode mixture. It was. The solvents for this polyamic acid solution are N-methyl-2-pyrrolidone and N, N-dimethylacetamide. Subsequently, the negative electrode mixture was dispersed in N-methyl-2-pyrrolidone to obtain a negative electrode mixture slurry. Subsequently, the negative electrode mixture slurry was uniformly applied to both surfaces of the negative electrode current collector 54A using a coating apparatus, and then dried. Finally, heating was performed in a vacuum atmosphere under conditions of 400 ° C. × 1 hour to form polyimide as a negative electrode binder. When the cycle characteristics of the secondary batteries of Experimental Examples 3-1 to 3-5 were examined, the results shown in Table 6 were obtained.

  When the coating method was used, the discharge capacity retention rate was lower than when the thermal spraying method was used even though the silicon iron-containing material having the same composition was used as the negative electrode active material. This is presumably because the adhesion of the negative electrode active material layer 54B to the negative electrode current collector 54A was not sufficient, and the resistance increased due to the presence of the negative electrode binder. For this reason, in the secondary battery of the present invention, if the thermal spraying method is used as the method for forming the negative electrode active material layer, the cycle characteristics are improved.

(Experimental examples 4-1 to 4-13)
As shown in Table 7, the same procedure as in Experimental Example 2-20 was performed except that the half width and the crystallite size of the negative electrode active material were changed. When the cycle characteristics of the secondary batteries of Examples 4-1 to 4-13 were examined, the results shown in Table 7 and FIG. 11 were obtained.

  Even when the full width at half maximum and the crystallinity size were changed, the same results as in Table 1 were obtained. In this case, when the half width was 20 ° or less and the crystallite size was 100 nm or more, the discharge capacity retention ratio was higher. For these reasons, in the secondary battery of the present invention, if the half-value width (2θ) of the diffraction peak in the (111) crystal plane of the negative electrode active material is 20 ° or less and the crystallite size is 100 nm or more, cycle characteristics Will be improved.

(Experimental examples 5-1 to 5-3)
Except that the plurality of negative electrode active material particles did not contain flat particles, the same procedures as in Experimental Examples 1-9, 2-18, and 2-20 were performed. When the cycle characteristics of the secondary batteries of Examples 5-1 to 5-3 were examined, the results shown in Table 8 were obtained.

  Even when the plurality of negative electrode active material particles did not contain flat particles, the same results as in Table 1 were obtained. In this case, when the flat particles were included, the discharge capacity retention rate was higher than when the flat particles were not included. For these reasons, in the secondary battery of the present invention, the cycle characteristics are further improved if the plurality of negative electrode active material particles include flat particles.

(Experimental examples 6-1 to 6-9)
As shown in Table 9, the same procedure as in Experimental Example 2-20 was performed except that the oxygen content in the negative electrode active material was changed. When the cycle characteristics of the secondary batteries of Examples 6-1 to 6-9 were examined, the results shown in Table 9 and FIG. 12 were obtained.

  Even when the oxygen content in the negative electrode active material was changed, the same results as in Table 1 were obtained. In this case, when the oxygen content was 1.5 atomic% or more and 40 atomic% or less, a high discharge capacity retention rate was obtained and a sufficient battery capacity was also obtained. For these reasons, in the secondary battery of the present invention, excellent cycle characteristics and high battery capacity can be obtained if the oxygen content in the negative electrode active material is 1.5 atomic% to 40 atomic%.

(Experimental examples 7-1 to 7-3)
As shown in Table 10, Experimental Example 2 except that the negative electrode active material layer 54B was formed so as to include a low oxygen content region and a high oxygen content region by intermittently introducing oxygen gas into the chamber. The same procedure as in -20 was performed. In this case, the high oxygen content region is sandwiched by the low oxygen content region, and they are alternately stacked. Further, the oxygen content in the negative electrode active material in the high oxygen content region was set to 5 atomic%. When the cycle characteristics of the secondary batteries of Examples 7-1 to 7-3 were examined, the results shown in Table 10 and FIG. 13 were obtained.

  Even when the negative electrode active material layer 54B includes a high oxygen content region and a low oxygen content region, the same results as in Table 1 were obtained. In this case, in the case where the high oxygen content region and the low oxygen content region were included, the discharge capacity retention rate was higher than in the case where they were not included. For these reasons, in the secondary battery of the present invention, if the negative electrode active material layer 54B includes a high oxygen content region and a low oxygen content region, the cycle characteristics are further improved.

(Experimental examples 8-1 to 8-12)
As shown in Table 11, the same procedure as in Experimental Example 2-20 was performed except that the ten-point average roughness Rz of the surface of the negative electrode current collector 54A was changed. In this case, in order to adjust the ten-point average roughness Rz, not only the electrolytic copper foil but also a rolled copper foil that was sandblasted as necessary was used as the negative electrode current collector 54A. When the cycle characteristics of the secondary batteries of Examples 8-1 to 8-12 were examined, the results shown in Table 11 and FIG. 14 were obtained.

  Even when the ten-point average roughness Rz was changed, the same results as in Table 1 were obtained. In this case, when the ten-point average roughness Rz was 1.5 μm or more, and further 3 μm or more and 30 μm or less, a high discharge capacity retention rate was obtained and a sufficient battery capacity was also obtained. For these reasons, in the secondary battery of the present invention, if the ten-point average roughness Rz of the surface of the negative electrode current collector 54A is 1.5 μm or more, preferably 3 μm or more and 30 μm or less, excellent cycle characteristics and high battery Capacity is obtained.

(Experimental examples 9-1 to 9-8)
As shown in Table 12 and Table 13, the same procedure as in Experimental Example 2-20 was performed except that the composition of the electrolytic solution was changed. In this case, 4-fluoro-1,3-dioxolan-2-one (FEC) or 4,5-difluoro-1,3-dioxolan-2-one (DFEC) was used as a solvent. As other solvents, vinylene carbonate (VC), vinyl ethylene carbonate (VEC), propene sultone (PRS), sulfobenzoic anhydride (SBAH) or sulfopropionic anhydride (SPAH) was used. As an electrolyte salt, lithium tetrafluoroborate (LiBF ₄ ) was used. The content of other solvents in the solvent was 1% by weight. The LiBF ₄ content was 0.1 mol / kg with respect to the solvent, and the LiPF ₆ content was 0.9 mol / kg with respect to the solvent. When the cycle characteristics of the secondary batteries of Examples 9-1 to 9-8 were examined, the results shown in Table 12 and Table 13 were obtained.

  Even when the composition of the electrolytic solution was changed, the same results as in Table 1 were obtained. In particular, when FEC or the like was added, the discharge capacity retention rate was higher than when no FEC was added. For these reasons, in the secondary battery of the present invention, if a halogenated chain carbonate, halogenated cyclic carbonate, unsaturated carbon-bonded cyclic carbonate, sultone or acid anhydride is used as the solvent, cycle characteristics are further improved. To do. Moreover, if lithium tetrafluoroborate is used as the electrolyte salt, the cycle characteristics are further improved.

(Experimental examples 10-1, 10-21)
A procedure similar to that of Experimental Example 2-20 was performed, except that a square secondary battery was produced. In this case, first, the positive electrode 21 and the negative electrode 22 were prepared, and then the positive electrode lead 24 made of aluminum was welded to the positive electrode current collector 21A, and the negative electrode lead 25 made of nickel was welded to the negative electrode current collector 22A. . Subsequently, the positive electrode 21, the separator 23, and the negative electrode 22 were laminated in this order and wound in the longitudinal direction, and then formed into a flat shape to produce the battery element 20. Subsequently, after the battery element 20 was accommodated in the metal battery can 11 shown in Table 14, the insulating plate 12 was disposed on the battery element 20. Subsequently, the positive electrode lead 24 was welded to the positive electrode pin 15 and the negative electrode lead 25 was welded to the battery can 11, and then the battery lid 13 was laser welded to the open end of the battery can 11. Finally, an electrolyte was injected into the battery can 11 through the injection hole 19, and then the injection hole 19 was closed with a sealing member 19A to complete a square battery. When the cycle characteristics of the secondary batteries of Examples 10-1 and 10-2 were examined, the results shown in Table 14 were obtained.

  Even when the battery structure was changed, the same results as in Table 1 were obtained. In particular, when the battery structure is a square shape, the discharge capacity retention rate is higher than when the battery structure is a laminate film type. In this case, when the material of the battery can 11 was iron, the discharge capacity retention rate was higher. For these reasons, in the secondary battery of the present invention, if the battery structure is square, the cycle characteristics are further improved.

  From the results shown in Tables 1 to 14 and FIGS. 10 to 14, the following was confirmed. In the secondary battery of the present invention, the negative electrode active material contains silicon and iron as constituent elements, and the content of iron in the negative electrode active material is 0.05% by weight or more. As a result, the cycle characteristics are improved without depending on the oxygen content in the negative electrode active material, the presence or absence of the low oxygen content region and the high oxygen content region, the composition of the electrolytic solution, or the battery structure.

  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 of the present invention is not necessarily limited to the secondary battery, but may be other electrochemical devices. 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 by insertion and extraction of lithium ions is described as the type of the secondary battery, but is not necessarily limited thereto. The secondary battery of the present invention is also applicable to a secondary battery in which the capacity of the negative electrode includes a capacity due to insertion and extraction of lithium ions and a capacity due to precipitation and dissolution of lithium metal, and is represented by the sum of these capacities Is possible. In this case, a material capable of inserting and extracting lithium ions is used as the negative electrode active material, and the chargeable capacity of the material is set to be smaller than the discharge capacity of the positive electrode.

  Further, in the above-described embodiments and examples, the case where the battery structure is a square shape, the cylindrical shape, or the laminate film type, or the case where the battery element has a winding structure has been described as an example. However, the secondary battery of the present invention can be applied to a case where the battery has another battery structure such as a coin type or a button type, 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 element of the electrode reactant is described, but the present invention is not necessarily limited thereto. The electrode reactant may be, for example, another group 1 element such as sodium (Na) or potassium (K), a group 2 element such as magnesium or calcium, or another light metal 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.

  Further, in the above-described embodiments and examples, the appropriate range derived from the results of the examples is described for the iron content in the negative electrode active material in the secondary battery of the present invention. However, the explanation does not completely deny the possibility that the iron content is outside the above-mentioned range. In other words, the appropriate range described above is a particularly preferable range for obtaining the effect of the present invention, and the iron content may be slightly deviated from the above range as long as the effect of the present invention is obtained. This is because the total content of iron and additional metal elements, the half width and crystallite size of the negative electrode active material, the oxygen content in the negative electrode active material, or the ten-point average roughness Rz of the surface of the negative electrode current collector, etc. The same applies to.

  1, 22A, 42A, 54A ... negative electrode current collector, 2, 22B, 42B, 54B ... negative electrode active material layer, 11, 31 ... battery can, 12, 32, 33 ... insulating plate, 13, 34 ... battery lid, 14 DESCRIPTION OF SYMBOLS ... Terminal board, 15 ... Positive electrode pin, 16 ... Insulating case, 17, 37 ... Gasket, 18 ... Cleavage valve, 19 ... Injection hole, 19A ... Sealing member, 20 ... Battery element, 21, 41, 53 ... Positive electrode, 21A , 41A, 53A ... positive electrode current collector, 21B, 41B, 53B ... positive electrode active material layer, 22, 42, 54 ... negative electrode, 23, 43, 55 ... separator, 24, 45, 51 ... positive electrode lead, 25, 46, 52 ... Negative electrode lead, 35 ... Safety valve mechanism, 35A ... Disk plate, 36 ... Heat sensitive resistance element, 40, 50 ... Winding electrode body, 44 ... Center pin, 56 ... Electrolyte layer, 57 ... Protection tape, 61 ... Adhesion film , 60 ... exterior member, 01 ... anode active material particles, 201P ... flat particles, 202 ... gap, P1 ... contact portion, P2 ... noncontact portion.

Claims (19)

A positive electrode and a negative electrode, and an electrolyte containing a solvent and an electrolyte salt;
The negative electrode includes a crystalline negative electrode active material capable of inserting and extracting an electrode reactant,
The crystalline negative electrode active material contains silicon (Si) and iron (Fe) as constituent elements, and the content of iron in the crystalline negative electrode active material is 0.05% by weight or more. .   2. The secondary battery according to claim 1, wherein a half-value width (2θ) of a diffraction peak in a (111) crystal plane of the crystalline negative electrode active material obtained by X-ray diffraction is 20 ° or less.   The secondary battery according to claim 1, wherein a crystallite size caused by a (111) crystal plane of the crystalline negative electrode active material obtained by X-ray diffraction is 100 nm or more.   The negative electrode has the crystalline negative electrode active material on a negative electrode current collector, and the crystalline negative electrode active material is alloyed at least at a part of an interface with the negative electrode current collector. The secondary battery as described.   The crystalline negative electrode active materials are aluminum (Al), calcium (Ca), chromium (Cr), magnesium (Mg), manganese (Mn), nickel (Ni), potassium (K), copper (Cu) and titanium. The secondary battery according to claim 1, comprising at least one additional metal element of (Ti) as a constituent element.   The secondary battery according to claim 5, wherein the total content of iron and additional metal elements in the crystalline negative electrode active material is 0.2% by weight or more.   The secondary battery according to claim 1, wherein the crystalline negative electrode active material has a plurality of particles, and at least a part of the crystalline negative electrode active material has a flat shape extending in a direction intersecting a thickness direction of the negative electrode.   The secondary battery according to claim 1, wherein the crystalline negative electrode active material has voids therein.   The negative electrode has the crystalline negative electrode active material on a negative electrode current collector, and the crystalline negative electrode active material has a portion not in contact with a portion in contact with the surface of the negative electrode current collector; The secondary battery according to claim 1, comprising:   The secondary battery according to claim 1, wherein the crystalline negative electrode active material is formed by a thermal spraying method.   2. The crystalline negative electrode active material contains oxygen (O) as a constituent element, and the oxygen content in the crystalline negative electrode active material is 1.5 atomic% to 40 atomic%. The secondary battery as described.   The secondary battery according to claim 1, wherein the crystalline negative electrode active material has a high oxygen content region and a low oxygen content region in a thickness direction of the negative electrode.   The secondary electrode according to claim 1, wherein the negative electrode has the crystalline negative electrode active material on a negative electrode current collector, and a ten-point average roughness Rz of the surface of the negative electrode current collector is 1.5 μm or more. battery.   The secondary battery according to claim 13, wherein the ten-point average roughness Rz is 3 μm or more and 30 μm or less. The solvent includes a halogenated chain carbonate represented by the formula (1), a halogenated cyclic carbonate represented by the formula (2), and an unsaturated carbon bond represented by the formula (3) to the formula (5). The secondary battery according to claim 1, comprising at least one of cyclic carbonate, sultone, and 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 ), and a formula ( The secondary battery according to claim 1, comprising at least one of compounds represented by 6) to formula (11).

(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 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, and at least one of each is 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.)
_{LiN (C m F 2m + 1} SO 2) (C n F 2n + 1 SO 2) ... (9)
(M and n are integers of 1 or more.)

(R61 is a linear or branched perfluoroalkylene group having 2 to 4 carbon atoms.)
LiC (C _p F _{2p + 1} SO ₂ ) (C _q F _{2q + 1} SO ₂ ) (C _r F _{2r + 1} SO ₂ ) (11)
(P, q and r are integers of 1 or more.) The secondary battery according to claim 1, wherein the positive electrode includes a composite oxide represented by Formula (12) as a positive electrode active material.
LiNi _1-x M _x O ₂ (12)
(M is cobalt (Co), manganese, iron, aluminum, vanadium (V), tin (Sn), magnesium, titanium, strontium (Sr), calcium, zirconium (Zr), molybdenum (Mo), technetium (Tc), Ruthenium (Ru), tantalum (Ta), tungsten (W), rhenium (Re), ytterbium (Yb), copper, zinc (Zn), barium (Ba), boron (B), chromium, silicon, gallium (Ga) , Phosphorus (P), antimony (Sb), and niobium (Nb), where x is 0.005 <x <0.5.   The secondary battery according to claim 1, wherein the electrode reactant is lithium ion. A crystalline negative electrode active material capable of occluding and releasing the electrode reactant,
The crystalline negative electrode active material contains silicon and iron as constituent elements, and the content of iron in the crystalline negative electrode active material is 0.05% by weight or more.

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