JP5382413B2 - Negative electrode for secondary battery and secondary battery - Google Patents

Description

  The present invention relates to a negative electrode suitable for a secondary battery and a secondary battery including 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 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 (Li ⁺ ) for charge / discharge reactions are widely put into practical use because they have higher energy density than lead batteries and nickel cadmium batteries. This lithium ion secondary battery includes an electrolyte solution together with a positive electrode and a negative electrode, and the negative electrode has a negative electrode active material layer on a negative electrode current collector.

  As a negative electrode active material contained in the negative electrode active material layer, a carbon material such as graphite is widely used. Recently, since further improvement in battery capacity has been demanded as portable electronic devices have higher performance and multi-functions, the use of silicon or tin instead of carbon materials has been studied. This is because the theoretical capacity of silicon (4199 mAh / g) and the theoretical capacity of tin (994 mAh / g) are much larger than the theoretical capacity of graphite (372 mAh / g), so that a significant improvement in battery capacity can be expected.

  However, in the lithium ion secondary battery, since the negative electrode active material that occludes lithium during charge and discharge becomes highly active, the electrolytic solution is easily decomposed at the negative electrode interface, or a part of lithium is easily deactivated. There is a problem. This makes it difficult to obtain sufficient cycle characteristics and storage characteristics. This problem becomes remarkable when high theoretical capacity silicon or the like is used as the negative electrode active material.

  Therefore, various studies have been made to solve such problems of lithium ion secondary batteries and improve battery characteristics such as cycle characteristics and storage characteristics. For example, as a binder contained in the positive electrode active material layer of the positive electrode or the negative electrode active material layer of the negative electrode, a technique using a resin containing sulfur such as a polyamide elastomer containing a dicarboxylic acid structure, a siloxane-modified polyamideimide, or a polysulfone has been proposed. (For example, see Patent Documents 1 to 3). In addition, a technique using graphite coated with a polymer compound having a structure represented by C═O or C—O such as sodium polyglutamate as a negative electrode active material has been proposed (for example, Patent Documents 4 to 6). reference). In addition, a technique for forming a negative electrode active material layer by co-evaporating silicon and a resin such as polyimide (see, for example, Patent Document 7), or an organic acid alkali metal such as lithium glutamate for any of the positive electrode, the negative electrode, and the electrolyte A technique for adding a salt (see, for example, Patent Document 8) has also been proposed.

On the other hand, various technologies have also been proposed for lithium metal secondary batteries that utilize precipitation and dissolution of lithium for charge and discharge reactions. For example, for the purpose of improving cycle characteristics, protection including a structure in which a linear polymer such as polyamide is infiltrated into a three-dimensionally crosslinked polymer network matrix on a negative electrode active material layer made of lithium metal or the like A technique for forming a film (see, for example, Patent Document 9).
Japanese Patent Laid-Open No. 11-097029 JP 2001-068115 A JP 2008-010307 A JP 2006-310232 A JP 2007-014944 A JP 2007-059342 A JP 2007-095563 A Japanese Patent Laid-Open No. 08-298136 JP 2005-142156 A

  However, as described above, various studies have been made, but sufficient results have not been obtained. In particular, recent portable electronic devices are becoming more sophisticated and multifunctional, and their power consumption tends to increase. Therefore, the secondary battery is frequently charged and discharged repeatedly, and its cycle characteristics tend to deteriorate. It is in. From this, further improvement is desired regarding the cycle characteristics of the secondary battery.

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

The secondary battery of the present invention includes a positive electrode including a positive electrode active material capable of occluding and releasing electrode reactants, and capable of occluding and releasing electrode reactants and at least one of silicon and tin. And a negative electrode containing a polyamide compound having a carboxylic acid alkali metal base, and an electrolytic solution containing a non-aqueous solvent and an electrolyte salt. The “carboxylic acid alkali metal base” refers to a group in which a carboxylate ion group (—C (═O) —O—) and an ionized alkali metal element (cation) are ionically bonded. The “polyamide compound” refers to a polymer compound having a structure containing two or more amide bonds (—C (═O) —NH—). Furthermore, the “polyamide compound having a carboxylic acid alkali metal base” refers to a polymer compound in which one or two or more carboxylic acid alkali metal bases are introduced into the above-described polyamide compound.

The negative electrode for a secondary battery of the present invention can occlude and release an electrode reactant, and has a negative electrode active material having at least one of silicon and tin as a constituent element, and an alkali metal carboxylate. And a polyamide compound.

The negative electrode for a secondary battery of the present invention includes a negative electrode active material having at least one of silicon and tin as a constituent element and a polyamide compound having a carboxylic acid alkali metal base. Thereby, compared with the case where the polyamide compound is not included or the case where a carbon material is used as the negative electrode active material, chemical stability is improved. For this reason, the electrode reactant is efficiently occluded and released during the electrode reaction, and it is difficult to react with other substances such as an electrolytic solution . Therefore, according to the secondary battery of the present invention, since the negative electrode has the same configuration as the negative electrode for secondary battery of the present invention, the electrode reactant is efficiently occluded and released in the negative electrode during charging and discharging. In addition, since the decomposition of the electrolytic solution is suppressed, the cycle characteristics can be improved.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The description will be given in the following order.
1. First embodiment (example of negative electrode having a coating)
(1-1) Negative electrode usage example 1 according to the first embodiment (first secondary battery)
(1-2) Usage example 2 of the negative electrode according to the first embodiment (second secondary battery)
2. Second embodiment (example of negative electrode without a coating)
(2-1) Negative electrode usage example 1 according to the second embodiment (third secondary battery)
(2-2) Negative electrode usage example 2 (fourth secondary battery) according to the second embodiment

<1. First Embodiment>
FIG. 1 shows a cross-sectional configuration of a negative electrode according to the first embodiment of the present invention. This negative electrode is used for, for example, an electrochemical device such as a secondary battery, and includes a negative electrode current collector 1 having a pair of surfaces, a negative electrode active material layer 2 provided on the negative electrode current collector 1, and And a coating 3 provided on the negative electrode active material layer 2. The negative electrode active material layer 2 may be provided on both sides of the negative electrode current collector 1 or may be provided only on one side. The same applies to the coating 3. In the following, a description will be given of a case where the electrode reactant that is occluded and released in the negative electrode is lithium ion.

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

  In particular, the metal material described above preferably contains one or more metal elements that do not form an intermetallic compound with lithium. When an intermetallic compound is formed with lithium, it is easily affected by stress due to expansion and contraction of the negative electrode active material layer 2 during operation of the electrochemical device (for example, during charging and discharging of the secondary battery). For this reason, it is because there exists a possibility that current collection property may fall and the negative electrode active material layer 2 may peel from the negative electrode collector 1. FIG. Examples of such metal elements include copper, nickel, titanium (Ti), iron (Fe), and chromium (Cr).

  In addition, the metal material described above preferably contains any one or more of metal elements that are alloyed with the negative electrode active material layer 2. This is because the adhesion between the negative electrode current collector 1 and the negative electrode active material layer 2 is improved, so that the negative electrode active material layer 2 is difficult to peel from the negative electrode current collector 1. Examples of the metal element that does not form an intermetallic compound with lithium and alloyed with the negative electrode active material layer 2 include, for example, copper, nickel, or iron when the negative electrode active material layer 2 contains silicon as the negative electrode active material. Is mentioned. These metal elements are also preferable from the viewpoints of strength and conductivity.

  The negative electrode current collector 1 may have a single layer structure or a multilayer structure. When the negative electrode current collector 1 has a multilayer structure, for example, a layer adjacent to the negative electrode active material layer 2 is made of a metal material alloyed therewith, and a non-adjacent layer is made of another metal material. preferable.

  The surface of the negative electrode current collector 1 is preferably roughened. This is because the adhesion between the negative electrode current collector 1 and the negative electrode active material layer 2 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 subjected to the electrolytic treatment including the copper foil roughened by the electrolytic treatment is generally called “electrolytic copper foil”.

  The negative electrode active material layer 2 can contain any one or more of negative electrode materials that can occlude and release lithium ions and have at least one of silicon and tin as a constituent element as a negative electrode active material. Contains. The negative electrode active material layer 2 may contain other materials such as a conductive agent or a binder as necessary.

  The reason for including a negative electrode material capable of inserting and extracting lithium ions and having at least one of silicon (Si) and tin (Sn) as a constituent element is that a high energy density is obtained. is there. A negative electrode material having at least one of silicon and tin has at least a part of a simple substance, an alloy or a compound of silicon, a simple substance, an alloy or a compound of tin, or one or more phases thereof. It may be anything. Moreover, these may be individual and multiple types may be mixed.

  The “alloy” in the present invention includes an alloy containing one or more metal elements and one or more metalloid elements in addition to an alloy composed of two or more metal elements. Further, the “alloy” may contain a nonmetallic element. This structure includes a solid solution, a eutectic (eutectic mixture), an intermetallic compound, or one in which two or more of them coexist.

  Examples of the negative electrode material having a simple substance of silicon include a material mainly having a simple substance of silicon. The negative electrode active material layer 2 including this negative electrode material has, for example, a structure in which a second constituent element other than silicon and oxygen are present between silicon single layers. The total content of silicon and oxygen in the negative electrode active material layer 2 is preferably 50% by mass or more, and the content of silicon alone is particularly preferably 50% by mass or more. Examples of the second constituent element other than silicon include titanium (Ti), chromium, manganese (Mn), iron, cobalt (Co), nickel, copper, zinc (Zn), indium (In), and silver (Ag). , Magnesium (Mg), aluminum, germanium (Ge), tin, bismuth (Bi), antimony (Sb), and the like. The negative electrode active material layer 2 containing a material mainly composed of silicon can be formed, for example, by co-evaporation of silicon and other constituent elements.

As an alloy of silicon, for example, as a second constituent element other than silicon, among the group consisting of tin, nickel, copper, iron, cobalt, manganese, zinc, indium, silver, titanium, germanium, bismuth, antimony and chromium The thing which has at least 1 sort (s) of these is mentioned. Examples of the silicon compound include those having oxygen or carbon (C), and may contain the second constituent element described above in addition to silicon. Examples of silicon alloys or compounds include SiB ₄ , SiB ₆ , Mg ₂ Si, Ni ₂ Si, TiSi ₂ , MoSi ₂ , CoSi ₂ , NiSi ₂ , CaSi ₂ , CrSi ₂ , Cu ₅ Si, FeSi ₂ , MnSi. ₂ , NbSi ₂ , TaSi ₂ , VSi ₂ , WSi ₂ , ZnSi ₂ , SiC, Si ₃ N ₄ , Si ₂ N ₂ O, SiO _v (0 <v ≦ 2) or LiSiO.

As an alloy of tin, for example, as a second constituent element other than tin, among the group consisting of silicon, nickel, copper, iron, cobalt, manganese, zinc, indium, silver, titanium, germanium, bismuth, antimony and chromium The thing which has at least 1 sort (s) of these is mentioned. Examples of the tin compound include those having oxygen or carbon, and may contain the above-described second constituent element in addition to tin. Examples of tin alloys or compounds include SnO _w (0 <w ≦ 2), SnSiO ₃ , LiSnO, Mg ₂ Sn, and the like.

  In particular, as the negative electrode material having at least one of silicon and tin, for example, a material having tin and the second constituent element in addition to tin as the first constituent element is preferable. The second constituent element is cobalt, iron, magnesium, titanium, vanadium (V), chromium, manganese, nickel, copper, zinc, gallium, zirconium, niobium (Nb), molybdenum (Mo), silver, indium, cerium ( Ce), hafnium, tantalum (Ta), tungsten (W), bismuth and silicon. The third constituent element is at least one selected from the group consisting of boron, carbon, aluminum, and phosphorus (P). This is because the inclusion of the second and third constituent elements improves the cycle characteristics when the negative electrode is used in an electrochemical device such as a secondary battery.

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

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

  The SnCoC-containing material has a phase containing tin, cobalt, and carbon, and the phase is preferably a low crystalline or amorphous phase. This phase is a reaction phase capable of reacting with lithium ions, whereby excellent cycle characteristics can be obtained. The half-value width of the diffraction peak obtained by X-ray diffraction of this phase is 1.0 ° or more at a diffraction angle 2θ when CuKα ray is used as the specific X-ray and the drawing speed is 1 ° / min. Is preferred. This is because lithium is more smoothly inserted and extracted, and the reactivity with the electrolytic solution is reduced when the negative electrode is used in an electrochemical device such as a secondary battery equipped with the electrolytic solution.

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

  In addition to the low crystalline or amorphous phase, the SnCoC-containing material may have a phase containing a simple substance or a part of each constituent element.

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

  As a measuring method for examining the bonding state of elements, for example, X-ray photoelectron spectroscopy (XPS) can be cited. This XPS irradiates the sample surface with soft X-rays (Al-Kα ray or Mg-Kα ray is used in a commercial apparatus), and measures the kinetic energy of photoelectrons jumping out of the sample surface. To elemental composition in the region of several nanometers and the bonding state of the elements.

  The binding energy of the core orbital electrons of the element changes in a first approximation in correlation with the charge density on the element. For example, when the charge density of the carbon element decreases due to an interaction with an element present in the vicinity, the outer electrons such as 2p electrons decrease, so the 1s electron of the carbon element exerts a strong binding force from the shell. Will receive. That is, the binding energy increases as the charge density of the element decreases. In XPS, when the binding energy increases, the peak shifts to a high energy region.

  In XPS, if the peak of carbon 1s orbital (C1s) is graphite, it appears at 284.5 eV in an energy calibrated apparatus so that the peak of 4f orbital (Au4f) of gold atom is obtained at 84.0 eV. . Moreover, if it is surface contamination carbon, it will appear at 284.8 eV. On the other hand, when the charge density of the carbon element is high, for example, when it is bonded to an element more positive than carbon, the C1s peak appears in a region lower than 284.5 eV. That is, when at least a part of carbon contained in the SnCoC-containing material is bonded to a metal element or a metalloid element that is another constituent element, the peak of the synthetic wave of C1s obtained for the SnCoC-containing material is 284. Appears in a region lower than 5 eV.

  When performing XPS measurement, it is preferable that the surface is lightly sputtered with an argon ion gun attached to the XPS apparatus when the surface is covered with surface-contaminated carbon. In addition, when a negative electrode having a SnCoC-containing material to be measured is present in an electrochemical device such as a secondary battery provided with an electrolytic solution, the electrochemical device is disassembled and the negative electrode is taken out, and then dimethyl carbonate, etc. It is good to wash with a volatile solvent. This is for removing the low-volatile solvent and the electrolyte salt present on the negative electrode surface. These samplings are preferably performed under an inert atmosphere.

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

  This SnCoC-containing material can be formed by, for example, a method in which a mixture obtained by mixing raw materials of each constituent element is melted in an electric furnace, a high-frequency induction furnace, an arc melting furnace or the like and then solidified. Also, various atomizing methods such as gas atomization or water atomization, methods using various mechanochemical reactions such as various roll methods, mechanical alloying methods, and mechanical milling methods may be used. Among these, a method using a mechanochemical reaction is preferable. This is because the SnCoC-containing material has a low crystalline or amorphous structure. In the method using the mechanochemical reaction, for example, a manufacturing apparatus such as a planetary ball mill or an attritor can be used.

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

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

  The negative electrode active material layer 2 using a negative electrode material capable of occluding and releasing lithium ions and having at least one of silicon and tin is, for example, a vapor phase method, a liquid phase method, a thermal spray method, or a coating method. Or it forms using the baking method or those 2 or more types of methods. In this case, the negative electrode current collector 1 and the negative electrode active material layer 2 are preferably alloyed at least at a part of the interface. Specifically, the constituent element of the negative electrode current collector 1 may be diffused into the negative electrode active material layer 2 at the interface between them, or the constituent element of the negative electrode active material layer 2 is diffused into the negative electrode current collector 1. These constituent elements may be diffused with each other. This is because breakage due to expansion and contraction of the negative electrode active material layer 2 during charging and discharging is suppressed, and electronic conductivity between the negative electrode current collector 1 and the negative electrode active material layer 2 is improved.

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

  The negative electrode active material made of the negative electrode material described above has a plurality of particles. That is, the negative electrode active material layer 2 has a plurality of negative electrode active material particles. The negative electrode active material particles are formed by, for example, the gas phase method described above. However, the negative electrode active material particles may be formed by a method other than the gas phase method.

  When the negative electrode active material particles are formed by a vapor phase method, the negative electrode active material particles may have a single layer structure formed through a single deposition process, or a plurality of deposition processes. You may have the multilayered structure formed through these. However, when the negative electrode active material particles are formed by a vapor deposition method that involves high heat during deposition, the negative electrode active material particles preferably have a multilayer structure. By performing the deposition process of the negative electrode material in a plurality of times (the negative electrode material is sequentially formed and deposited), the negative electrode current collector 1 is exposed to higher heat than when the deposition process is performed once. This is because the time required for heat treatment is shortened and it is difficult to receive thermal damage.

  The negative electrode active material particles grow, for example, from the surface of the negative electrode current collector 1 in the thickness direction of the negative electrode active material layer 2 and are connected to the negative electrode current collector 1 at the base. In this case, the negative electrode active material particles are formed by a vapor phase method, and it is preferable that the negative electrode active material particles are alloyed at least at a part of the interface with the negative electrode current collector 1 as described above. Specifically, the constituent elements of the negative electrode current collector 1 may be diffused into the negative electrode active material particles at the interface between them, or the constituent elements of the negative electrode active material particles are diffused into the negative electrode current collector 1. Alternatively, the constituent elements of both may diffuse to each other.

  In particular, the negative electrode active material layer 2 preferably has an oxide-containing film that covers the surface of the negative electrode active material particles (region in contact with the electrolytic solution) as necessary. When an anode is used in an electrochemical device such as a secondary battery equipped with an electrolytic solution, the oxide-containing film functions as a protective film against the electrolytic solution, so the decomposition reaction of the electrolytic solution is suppressed even after repeated charging and discharging. Because it is done. This oxide-containing film may cover a part of the surface of the negative electrode active material particles, or may cover the whole.

  This oxide-containing film contains an oxide of a metal element or a metalloid element. Examples of the metal element or metalloid oxide include oxides such as aluminum, silicon, zinc, germanium, and tin. Among these, this oxide-containing film preferably contains at least one oxide selected from the group consisting of silicon, germanium and tin, and particularly preferably contains an oxide of silicon. This is because the entire surface of the negative electrode active material particles can be easily covered and an excellent protective function can be obtained. Of course, the oxide-containing film may contain an oxide other than the above.

  The oxide-containing film is formed using one or more methods such as a gas phase method or a liquid phase method. Examples of the vapor phase method in this case include a vapor deposition method, a sputtering method, or a CVD method. Examples of the liquid phase method include a liquid phase precipitation method, a sol-gel method, a polysilazane method, an electrodeposition method, a coating method, or a coating method. Examples include dip coating. Among these, the liquid phase method is preferable, and the liquid phase precipitation method is more preferable. This is because the surface of the negative electrode active material particles can be easily covered over a wide range. In the liquid phase precipitation method, first, the surface of the anode active material particles is coated in a solution containing a fluoride complex of a metal element or a semi-metal group element and a dissolved species that easily coordinates fluoride ions as an anion scavenger. As described above, an oxide of a metal element or a semimetal group element is deposited. At this time, in the solution, fluoride ions generated from the fluoride complex are captured by the anion scavenger. Thereafter, the oxide-containing film is formed by washing with water and drying.

  Moreover, it is preferable that the negative electrode active material layer 2 has a metal material that does not alloy with lithium in the gaps between the particles of the negative electrode active material particles and the gaps in the particles as necessary. Since a plurality of negative electrode active material particles are bound via a metal material and the expansion and contraction of the negative electrode active material layer 2 are suppressed by the presence of the metal material in the gaps described above, the negative electrode is a secondary battery or the like. This is because the cycle characteristics are improved when used in this electrochemical device.

  This metal material has, for example, a metal element that does not alloy with lithium as a constituent element. Examples of such a metal element include at least one member selected from the group consisting of iron, cobalt, nickel, zinc, and copper, with cobalt being preferred. This is because the metal material can easily enter the gaps and an excellent binding function can be obtained. Of course, the metal material may have a metal element other than the above. However, the “metal material” mentioned here is not limited to a simple substance, but is a broad concept that includes alloys and metal compounds. This metal material is formed by, for example, a gas phase method or a liquid phase method, and among them, a liquid phase method such as an electrolytic plating method or an electroless plating method is preferable, and an electrolytic plating method is more preferable. This is because the metal material can easily enter the gap and the formation time can be shortened.

  The negative electrode active material layer 2 may have only one of the above-described oxide-containing film or metal material, or may have both. However, in order to further improve the cycle characteristics of an electrochemical device such as a secondary battery, it is preferable to have both.

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

  First, the case where the negative electrode active material layer 2 has an oxide-containing film together with a plurality of negative electrode active material particles will be described. FIG. 2 schematically shows the cross-sectional structure of the negative electrode of the present invention, and FIG. 3 schematically shows the cross-sectional structure of the negative electrode of the reference example. 2 and 3 show a case where the negative electrode active material particles have a single-layer structure.

  In the negative electrode of the present invention, as shown in FIG. 2, when a negative electrode material is deposited on the negative electrode current collector 1 by a vapor phase method such as vapor deposition, a plurality of negative electrodes are formed on the negative electrode current collector 1. Active material particles 201 are formed. In this case, when the surface of the negative electrode current collector 1 is roughened and a plurality of protrusions (for example, fine particles formed by electrolytic treatment) are present on the surface, the negative electrode active material particles 201 have the protrusions described above. Every time it grows in the thickness direction. For this reason, the plurality of negative electrode active material particles 201 are arranged on the negative electrode current collector 1 and connected to the negative electrode current collector 1 at the root. After that, for example, when the oxide-containing film 202 is formed on the surface of the negative electrode active material particle 201 by a liquid phase method such as a liquid phase precipitation method, the oxide-containing film 202 substantially covers the surface of the negative electrode active material particle 201. Cover all over. In particular, in this case, a wide range from the top to the root of the negative electrode active material particles 201 is covered. This wide covering state by the oxide-containing film 202 is a characteristic obtained when the oxide-containing film 202 is formed by a liquid phase method. That is, when the oxide-containing film 202 is formed by a liquid phase method, the covering action extends not only to the top of the negative electrode active material particles 201 but also to the root, so that the base is covered with the oxide-containing film 202.

  In contrast, in the negative electrode of the reference example, as shown in FIG. 3, for example, after a plurality of negative electrode active material particles 201 are formed by a vapor phase method, an oxide-containing film is formed by a vapor phase method such as a vapor deposition method. When 203 is formed, the oxide-containing film 203 covers only the tops of the negative electrode active material particles 201. This narrow covering state by the oxide-containing film 203 is a characteristic obtained when the oxide-containing film 203 is formed by a vapor phase method. In other words, when the oxide-containing film 203 is formed by a vapor phase method, the covering action does not reach the root of the negative electrode active material particles 201, so that the base is not covered by the oxide-containing film 203.

  In addition, although FIG. 2 demonstrated the case where the negative electrode active material layer 2 was formed by a vapor phase method, a plurality of negative electrode active materials are similarly applied when the negative electrode active material layer 2 is formed by a sintering method or the like. An oxide-containing film is formed so as to cover the entire surface of the particles.

  Next, the case where the negative electrode active material layer 2 has a metal material that does not alloy with lithium together with a plurality of negative electrode active material particles will be described. 4A and 4B show an enlarged cross-sectional structure of the negative electrode. FIG. 4A is a scanning electron microscope (SEM) photograph (secondary electron image), and FIG. 4B is an SEM image shown in FIG. It is a schematic picture. FIG. 4 shows a case where a plurality of negative electrode active material particles have a multilayer structure in the particles.

  When the negative electrode active material particles 201 have a multilayer structure, a plurality of gaps 204 are generated in the negative electrode active material layer 2 due to the dense structure, multilayer structure, and surface structure of the plurality of negative electrode active material particles 201. Yes. The gap 204 mainly includes two types of gaps 204A and 204B classified according to the cause of occurrence. The gap 204 </ b> A is generated between adjacent negative electrode active material particles 201, and the gap 204 </ b> B is generated between layers in the negative electrode active material particles 201.

  Note that a void 205 may be formed on the exposed surface (outermost surface) of the negative electrode active material particles 201. The void 205 is a void generated between the protrusions as a whisker-like fine protrusion (not shown) is generated on the surface of the negative electrode active material particle 201. The void 205 may occur over the entire exposed surface of the negative electrode active material particle 201 or may occur only in part. However, since the above-described whisker-like protrusions are generated on the surface every time the negative electrode active material particles 201 are formed, the voids 205 are generated not only on the exposed surface of the negative electrode active material particles 201 but also between the layers. There is.

  FIG. 5 shows another cross-sectional structure of the negative electrode and corresponds to FIG. The negative electrode active material layer 2 has a metal material 206 that does not alloy with lithium in the gaps 204A and 204B. In this case, the metal material 206 may be provided in only one of the gaps 204A and 204B, but it is preferable that the metal material 206 is provided in both of them. This is because a higher effect can be obtained.

  This metal material 206 enters the gap 204 </ b> A between the adjacent negative electrode active material particles 201. Specifically, when the negative electrode active material particles 201 are formed by a vapor phase method or the like, as described above, the negative electrode active material particles 201 grow for each protrusion existing on the surface of the negative electrode current collector 1. A gap 204 </ b> A is generated between the adjacent negative electrode active material particles 201. Since the gap 204A causes a decrease in the binding property of the negative electrode active material layer 2, the above-described gap 204A is filled with the metal material 206 in order to improve the binding property. In this case, it is sufficient that a part of the gap 204A is filled, but the larger the filling amount, the better. This is because the binding property of the negative electrode active material layer 2 is further improved. The filling amount of the metal material 206 is preferably 20% or more, more preferably 40% or more, and further preferably 80% or more.

  In addition, the metal material 206 enters the gap 204 </ b> B in the negative electrode active material particles 201. Specifically, when the negative electrode active material particles 201 have a multilayer structure, a gap 204B is generated between the layers. Since the gap 204B causes a decrease in the binding property of the negative electrode active material layer 2 in the same manner as the gap 204A, the gap 204B is filled with the metal material 206 in order to improve the binding property. ing. In this case, it is sufficient that a part of the gap 204B is filled, but a larger filling amount is preferable. This is because the binding property of the negative electrode active material layer 2 is further improved.

  In addition, the negative electrode active material layer 2 is provided in order to prevent negative whisker-like protrusions (not shown) generated on the exposed surface of the uppermost negative electrode active material particles 201 from adversely affecting the performance of the electrochemical device. The gap 205 may have a metal material 206. Specifically, when the negative electrode active material particles 201 are formed by a vapor phase method or the like, fine whisker-like protrusions are formed on the surface thereof, and voids 205 are generated between the protrusions. The voids 205 increase the surface area of the negative electrode active material particles 201 and increase the amount of irreversible coating film formed on the surface of the negative electrode active material particles 201, which may cause a decrease in the degree of progress of the electrode reaction. Therefore, the metal material 206 is embedded in the above-described gap 205 in order to suppress a decrease in the progress of the electrode reaction. In this case, it is sufficient that a part of the gap 205 is buried, but it is preferable that the amount to be buried is larger. This is because a decrease in the degree of progress of the electrode reaction is further suppressed. In FIG. 5, the fact that the metal material 206 is scattered on the surface of the uppermost negative electrode active material particle 201 indicates that the above-described fine protrusions are present at the spot. Of course, the metal material 206 does not necessarily have to be scattered on the surface of the negative electrode active material particle 201, and may cover the entire surface.

  In particular, the metal material 206 that has entered the gap 204B also functions to fill the gap 205 in each layer. Specifically, when the negative electrode active material particles 201 are deposited a plurality of times, the fine protrusions described above are generated on the surface of the negative electrode active material particles 201 every time the negative electrode active material particles 201 are deposited. From this, the metal material 206 is not only filled in the gap 204B in each layer, but also fills the gap 205 in each layer.

  Before confirmation, in FIGS. 4 and 5, the case where the negative electrode active material particles 201 have a multilayer structure and both the gaps 204 </ b> A and 204 </ b> B exist in the negative electrode active material layer 2 has been described. The substance layer 2 has a metal material 206 in the gaps 204A and 204B. On the other hand, when the negative electrode active material particle 201 has a single-layer structure and only the gap 204A exists in the negative electrode active material layer 2, the negative electrode active material layer 2 has the metal material 206 only in the gap 204A. It will have. Of course, since the gap 205 is generated in both cases, the gap 205 includes the metal material 206 in either case.

  In addition to the above-described negative electrode material having at least one of silicon and tin as a constituent element, a negative electrode material capable of inserting and extracting other lithium ions may be included. Examples of other negative electrode materials include carbon materials. Examples of the carbon material include graphitizable carbon, non-graphitizable carbon having a (002) plane spacing of 0.37 nm or more, and graphite having a (002) plane spacing of 0.34 nm or less. It is. More specifically, there are pyrolytic carbons, cokes, glassy carbon fibers, organic polymer compound fired bodies, activated carbon or carbon blacks. 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 carbon material has very little change in crystal structure due to insertion and extraction of the electrode reactant. For this reason, for example, when used together with the above negative electrode material, a high energy density can be obtained, and excellent cycle characteristics can be obtained when the negative electrode is used in an electrochemical device such as a secondary battery. Since it functions also as an agent, it is preferable. The shape of the carbon material may be any of fibrous, spherical, granular or scale-like.

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

  Examples of the 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. Note that the conductive agent may be a metal material or a conductive polymer as long as it is a conductive material.

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

  The coating 3 is formed on the negative electrode active material layer 2 after the negative electrode active material layer 2 is formed on the negative electrode current collector 1, and is a polyamide compound (hereinafter referred to as polyamide) having a carboxylic acid alkali metal base. 1 type or 2 types or more). Thereby, the chemical stability at the time of electrode reaction improves. Therefore, when used in electrochemical devices such as secondary batteries equipped with electrolytes, lithium ions are efficiently occluded and released during charge and discharge, and the decomposition of the electrolyte is suppressed, contributing to improved cycle characteristics. To do. The coating 3 may be provided so as to cover the entire surface of the negative electrode active material layer 2 or may be provided so as to cover a part of the surface thereof. Moreover, a part of the coating 3 may enter the inside of the negative electrode active material layer 2.

  The polyamide compound is arbitrary as long as it is a polymer compound having a structure containing two or more amide bonds together with one or two or more carboxylic acid alkali metal bases. The reason for having an alkali metal carboxylate and a plurality of amide bonds is that, for example, it is difficult to elute into an electrolyte containing an organic solvent and it is difficult to decompose by an oxidation-reduction reaction. That is, the chemical stability of the polymer compound itself is increased.

  The alkali metal carboxylate may be introduced into a part other than the repeating unit (monomer unit) in the polyamide compound (for example, the terminal part of the polymer) or directly to the main chain part in the repeating unit. It may be introduced. The alkali metal carboxylate may be introduced via a divalent linking group to the main chain in the repeating unit. Of course, the alkali metal carboxylate may be introduced into at least one of the repeating units. Especially, it is preferable that the polyimide compound has a carboxylic acid alkali metal base in a repeating unit. This is because a high effect can be obtained.

  Moreover, the kind of the metal element which comprises the cation ion-bonded with a carboxylate ion group is arbitrary if it is any 1 type or 2 types or more among alkali metal elements. The reason why the metal element composing the cation is an alkali metal element is that it has sufficient chemical stability and is easily dissolved in a polar solvent as compared with other metal elements. For this reason, when the coating film 3 is formed, the uniform coating film 3 is easily formed in a small amount, and elution into the electrolyte is suppressed, for example, when used in a secondary battery including an electrolyte containing an organic solvent. The That is, a negative electrode having high chemical stability can be easily produced, and the chemical stability is maintained well. Among these alkali metal elements, lithium is preferable. This is because a higher effect can be obtained.

  Examples of the polyamide compound include an aliphatic compound having an alkali metal carboxylate base and a plurality of amide bonds and an aliphatic skeleton in the repeating unit, and an aromatic compound having an alkali metal carboxylate base and a plurality of amide bonds and an aromatic in the repeating unit. And aromatic compounds containing an aromatic skeleton, and copolymers having both of these repeating units. Among these, the polyamide compound is preferably an aliphatic compound. This is because a higher effect can be obtained. As such an aliphatic or aromatic polyamide compound, for example, a polymer compound having at least one of the structures represented by the formulas (1) and (2) is preferable. This is because a high effect can be obtained. In addition, “they are halogenated” explained in the formulas (1) and (2) means that one part or all of hydrogen contained in the hydrocarbon group is one or more of the halogen elements. It is that it was replaced with an element.

（Ｒ１は３価の飽和脂肪族炭化水素基、３価の不飽和脂肪族炭化水素基、あるいはそれらがハロゲン化された３価の基、または脂環式の環状構造を含む３価の基あるいは芳香族環を含む３価の基であり、Ｍ１はアルカリ金属元素であり、ａ１は１以上の整数である。）

(R1 is a trivalent saturated aliphatic hydrocarbon group, a trivalent unsaturated aliphatic hydrocarbon group, a trivalent group in which they are halogenated, or a trivalent group containing an alicyclic ring structure, or (It is a trivalent group containing an aromatic ring, M1 is an alkali metal element, and a1 is an integer of 1 or more.)

（Ｒ２は２価の飽和脂肪族炭化水素基、２価の不飽和脂肪族炭化水素基あるいはそれらがハロゲン化された２価の基、または脂環式の環状構造を含む２価の基あるいは芳香族環を含む２価の基であり、Ｒ３は４価の飽和脂肪族炭化水素基、４価の不飽和脂肪族炭化水素基あるいはそれらがハロゲン化された４価の基、または脂環式の環状構造を含む４価の基あるいは芳香族環を有する４価の基であり、Ｍ２およびＭ３はアルカリ金属元素であり、ｂ１は１以上の整数である。）

(R2 is a divalent saturated aliphatic hydrocarbon group, a divalent unsaturated aliphatic hydrocarbon group, a divalent group in which they are halogenated, or a divalent group or fragrance containing an alicyclic ring structure. R3 is a tetravalent saturated aliphatic hydrocarbon group, a tetravalent unsaturated aliphatic hydrocarbon group, a tetravalent group in which they are halogenated, or an alicyclic group. A tetravalent group containing a cyclic structure or a tetravalent group having an aromatic ring, M2 and M3 are alkali metal elements, and b1 is an integer of 1 or more.)

  R1 described in formula (1) is a trivalent hydrocarbon group, a trivalent group in which part or all of the hydrogen of the hydrocarbon group is substituted with a halogen element, or an alicyclic ring structure or aromatic The structure is arbitrary as long as it is a trivalent group containing one or more group rings. The type of the halogen element is arbitrary, but fluorine, chlorine or bromine is preferable. This is because chemical stability is higher than in the case of other halogen elements. The same applies to R2 and R3 described in the formula (2) except for the valence of the group.

  Examples of the saturated hydrocarbon group described in the formulas (1) and (2) include linear or branched hydrocarbon groups, and examples of the unsaturated hydrocarbon group include linear or branched carbon groups. A hydrocarbon group having one or more double bonds is exemplified. Examples of the divalent to tetravalent group having an aromatic ring described in the formulas (1) and (2) include skeletons represented by the formulas (A-1) to (A-5), for example. Or a group containing any of the above. Examples of the divalent to tetravalent group containing an alicyclic ring structure include a group containing a skeleton represented by the formula (B-1) and a group containing a cycloalkane skeleton.

  As a structure shown to Formula (1), the structure represented by Formula (1-1)-Formula (1-4) is mentioned, for example. More specifically, the polymer compound having the structure represented by Formula (1-1) is poly-γ- lithium glutamate or the like. Examples of the polymer compound having the structure represented by Formula (1-2) include poly-β-lithium aspartate. Examples of the polymer compound having the structure represented by Formula (1-3) include sodium poly-γ-glutamate. Examples of the polymer compound having the structure represented by the formula (1-4) include poly-α-lithium glutamate. Moreover, as a structure shown to Formula (2), the structure represented by Formula (2-1) is mentioned, for example. More specifically, the polymer compound having the structure shown in Formula (2-1) is poly (dilithium amic acid) or the like. The polyamide compound may be a polymer compound having these structures alone or may be a polymer compound having a plurality of types in combination. Moreover, these may be used independently for the film 3, and multiple types may be mixed.

（ａ２〜ａ５は１以上の整数である。）

(A2 to a5 are integers of 1 or more.)

（ｂ２は１以上の整数である。）

(B2 is an integer of 1 or more.)

  In addition, if it has a structure containing a plurality of amide bonds together with an alkali metal carboxylate base, it is limited to the structure shown in the above formula (1-1) to formula (1-4) or formula (2-1). It is not a thing. The same applies to the structures shown in the formulas (1) and (2).

  Further, the coating 3 may contain other compounds in addition to the polyamide compound described above. For example, an alkali metal salt (except for those corresponding to the polyamide compound described above) or an alkaline earth metal salt is used. May be included. This is because, since the film resistance is suppressed, the cycle characteristics are further improved when the negative electrode is used in an electrochemical device such as a secondary battery. The “alkaline earth metal” includes beryllium (Be) and magnesium, and refers to a group 2 element in the long-period periodic table.

Examples of such alkali metal salts or alkaline earth metal salts include carbonates, halide salts, borates, phosphates, and sulfonates of alkali metal elements or alkaline earth metal elements. Specifically, for example, lithium carbonate (Li ₂ CO ₃ ), lithium fluoride (LiF), lithium tetraborate (Li ₂ B ₄ O ₇ ), lithium metaborate (LiBO ₂ ), lithium pyrophosphate (Li ₄₎ P ₂ O ₇ ), lithium tripolyphosphate (Li ₅ P ₃ O ₁₀ ), lithium orthosilicate (Li ₄ SiO ₄ ), lithium metasilicate (Li ₂ SiO ₃ ), dilithium ethanedisulfonate, dilithium propanedisulfonate, Dilithium sulfoacetate, dilithium sulfopropionate, dilithium sulfobutanoate, dilithium sulfobenzoate, dilithium succinate, trilithium sulfosuccinate, dilithium squarate, magnesium ethanedisulfonate, magnesium propanedisulfonate, magnesium sulfoacetate , Magnesium sulfopropionate, sulfo Magnesium butanoate, Magnesium sulfobenzoate, Magnesium succinate, Trimagnesium disulfosuccinate, Calcium ethanedisulfonate, propane disulfonate, calcium sulfoacetate, calcium sulfopropionate, calcium sulfobutanoate, calcium sulfobenzoate, calcium succinate Or tricalcium disulfosuccinate. These may be single and multiple types may be mixed.

  Examples of the method for forming the coating 3 include a liquid phase method such as a coating method, a dipping method, or a dip coating method, and a vapor phase method such as a vapor deposition method, a sputtering method, or a CVD (Chemical Vapor Deposition) method. Can be mentioned. About these methods, you may use independently and may use 2 or more types of methods together. Among these, as the liquid phase method, it is preferable to form the coating 3 using a solution containing any one or more of the polyamide compounds. Specifically, for example, in the dipping method, the negative electrode current collector 1 on which the negative electrode active material layer 2 is formed is dipped in a solution containing the polyamide compound, or in the coating method, the solution containing the polyamide compound is dipped in the negative electrode active material. It is applied to the surface of the material layer 2. This is because a good film 3 having high chemical stability is easily formed. Examples of the solvent for dissolving the polyamide compound include a highly polar solvent such as water.

  This negative electrode is manufactured, for example, by the following procedure.

  First, the negative electrode active material layer 2 is formed on both surfaces of the negative electrode current collector 1. When forming the negative electrode active material layer 2, a negative electrode material is deposited on the surface of the negative electrode current collector 1 by a vapor phase method such as a vapor deposition method to form a plurality of negative electrode active material particles. Subsequently, if necessary, an oxide-containing film is formed by a liquid phase method such as a liquid phase deposition method, or a metal material is formed by a liquid phase method such as an electrolytic plating method. Finally, the film 3 is formed on the surface of the negative electrode active material layer 2. In the case of forming the film 3, for example, a solution having a concentration of 1% by weight to 5% by weight is prepared as a solution containing a polyamide compound. After that, the negative electrode current collector 1 on which the negative electrode active material layer 2 is formed is immersed in the solution for several seconds, and then pulled up and dried. Alternatively, the above-described solution is prepared, and applied to the surface of the negative electrode active material layer 2 and dried. Thereby, the negative electrode is completed.

  According to this negative electrode and its manufacturing method, the coating 3 containing the polyamide compound is provided on the negative electrode active material layer 2 containing the negative electrode active material having at least one of silicon and tin as a constituent element. Thereby, compared with the case where the film is not formed or the case where a carbon material is included as a negative electrode active material, for example, chemical stability is improved. Therefore, when this negative electrode is used in an electrochemical device such as a secondary battery, lithium ions efficiently pass through the coating 3 in the negative electrode, and are favorably occluded and released. In addition, at this time, it becomes difficult for the negative electrode to react with another substance (for example, an electrolytic solution in a secondary battery). For this reason, it can contribute to the improvement of cycling characteristics. In this case, if the coating film 3 is formed using a solution containing the above-described polyamide compound, specifically, a simple environmental process such as an immersion process or a coating process is used, special environmental conditions such as a reduced pressure environment are required. Compared with the case where the method is used, the favorable film 3 can be easily formed.

  If the negative electrode active material is in the form of a plurality of particles and the negative electrode active material layer includes an oxide-containing film that covers the surface of the negative electrode active material, higher effects can be obtained. Further, when the negative electrode active material is in a plurality of particles and the negative electrode active material layer contains a metal material that does not alloy with lithium in the gaps inside, the higher effect can be obtained.

  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 negative electrode is used as follows.

[(1-1) First Secondary Battery]
6 and 7 show a cross-sectional configuration of the first secondary battery, and FIG. 7 shows an enlarged part of the spirally wound electrode body 20 shown in FIG. The secondary battery described here is, for example, a lithium ion secondary battery in which the capacity of the negative electrode 22 is expressed based on insertion and extraction of lithium ions.

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

  The battery can 11 is made of, for example, a metal material such as iron, aluminum, or an alloy thereof, and one end thereof is closed and the other end is opened. The pair of insulating plates 12 and 13 are arranged so as to extend perpendicular to the winding peripheral surface with the winding electrode body 20 interposed therebetween.

  A battery lid 14 and a safety valve mechanism 15 and a heat sensitive resistance element (Positive Temperature Coefficient: PTC element) 16 provided inside thereof are caulked and attached to an open end portion of the battery can 11 via a gasket 17. ing. Thereby, the inside of the battery can 11 is sealed. The battery lid 14 is made of the same material as the battery can 11, for example. The safety valve mechanism 15 is electrically connected to the battery lid 14 via the heat sensitive resistance element 16. In the safety valve mechanism 15, when the internal pressure becomes a certain level or more due to an internal short circuit or external heating, the disk plate 15 </ b> A is reversed and the electric power between the battery lid 14 and the wound electrode body 20 is reversed. Connection is broken. The heat sensitive resistive element 16 limits the current by increasing the resistance according to the temperature rise, and prevents abnormal heat generation due to a large current. The gasket 17 is made of, for example, an insulating material, and asphalt is applied to the surface thereof.

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

  For example, the positive electrode 21 is obtained by providing a positive electrode active material layer 21B on both surfaces of a positive electrode current collector 21A having a pair of surfaces. The positive electrode current collector 21A is made of, for example, a metal material such as aluminum, nickel, or stainless steel. The positive electrode active material layer 21B includes a positive electrode active material, and may include other materials such as a binder and a conductive agent as necessary.

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

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

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

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

  The negative electrode 22 has the same configuration as the negative electrode described above. For example, the negative electrode active material layer 22B and the coating 22C are provided on both surfaces of a negative electrode current collector 22A having a pair of surfaces. The configurations of the negative electrode current collector 22A, the negative electrode active material layer 22B, and the coating 22C are the same as the configurations of the negative electrode current collector 1, the negative electrode active material layer 2, and the coating 3 in the above-described negative electrode, respectively. In the negative electrode 22, the charge capacity of the negative electrode material capable of inserting and extracting lithium ions is preferably larger than the charge capacity of the positive electrode 21. This is because even when the battery is fully charged, the possibility that lithium ions will be deposited as dendrites on the negative electrode 22 is reduced.

  The separator 23 separates the positive electrode 21 and the negative electrode 22 and allows lithium ions to pass through while preventing a short circuit of current due to contact between the two electrodes. The separator 23 is made of, for example, a porous film made of a synthetic resin such as polytetrafluoroethylene, polypropylene, or polyethylene, or a porous film made of ceramic, and these two or more kinds of porous films are laminated. It may be what was done. Among these, a porous film made of polyolefin is preferable because it is excellent in short-circuit preventing effect and can improve the safety of the secondary battery due to the shutdown effect. In particular, polyethylene is preferable because a shutdown effect can be obtained at 100 ° C. or higher and 160 ° C. or lower and the electrochemical stability is excellent. Polypropylene is also preferable, and other resins having chemical stability may be copolymerized with polyethylene or polypropylene, or may be blended.

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

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

  Examples of the non-aqueous solvent include ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, methyl propyl carbonate, γ-butyrolactone, γ-valerolactone, 1,2-dimethoxyethane, tetrahydrofuran, 2-methyltetrahydrofuran, tetrahydropyran, 1,3-dioxolane, 4-methyl-1,3-dioxolane, 1,3-dioxane, 1,4-dioxane, methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, Methyl butyrate, methyl isobutyrate, methyl trimethylacetate, ethyl trimethylacetate, acetonitrile, glutaronitrile, adiponitrile, methoxyacetonitrile, 3-methoxypropionitrile, N, N-dimethylformamide, N-methylpyrrolidinone, N -Methyloxazolidinone, N, N'-dimethylimidazolidinone, nitromethane, nitroethane, sulfolane, trimethyl phosphate or dimethyl sulfoxide. Among these, at least one selected from the group consisting of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate is preferable. This is because excellent battery capacity, cycle characteristics and storage characteristics can be obtained. In this case, in particular, a high viscosity (high dielectric constant) solvent such as ethylene carbonate or propylene carbonate (for example, relative dielectric constant ε ≧ 30) and a low viscosity solvent such as dimethyl carbonate, ethyl methyl carbonate or diethyl carbonate (for example, A combination with (viscosity ≦ 1 mPa · s) is more preferable. This is because the dissociation property of the electrolyte salt and the ion mobility are improved, so that a higher effect can be obtained.

  In particular, the solvent contains at least one of a chain carbonate ester having a halogen represented by formula (3) as a constituent element and a cyclic carbonate ester having a halogen represented by formula (4) as a constituent element. It is preferable. 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.

（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.)

  In addition, R11-R16 demonstrated in Formula (3) may be the same, and may differ. The same applies to R17 to R20 described in the formula (4). Although the kind of halogen is not specifically limited, For example, at least 1 type in the group which consists of a fluorine, chlorine, and a bromine is mentioned, Among these, a fluorine is preferable. This is because a high effect can be obtained. Of course, other halogens may be used.

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

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

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

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

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

（Ｒ２１およびＲ２２は水素基あるいはアルキル基である。）

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

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

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

（Ｒ２７はアルキレン基である。）

(R27 is an alkylene group.)

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

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

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

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

  Further, the solvent preferably contains an acid anhydride. This is because the chemical stability of the electrolytic solution is further improved. Examples of the acid anhydride include carboxylic acid anhydrides such as succinic anhydride, glutaric anhydride or maleic anhydride, disulfonic anhydrides such as ethanedisulfonic anhydride or propanedisulfonic anhydride, sulfobenzoic anhydride, anhydrous Examples thereof include anhydrides of carboxylic acid such as sulfopropionic acid or sulfobutyric anhydride and sulfonic acid, among which succinic anhydride or anhydrous sulfobenzoic acid is preferable. These may be single and multiple types may be mixed. The content of the acid anhydride in the solvent is, for example, 0.5% by weight or more and 5% by weight or less.

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

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

  Among these, at least one selected from the group consisting 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.

  This electrolyte salt preferably contains at least one member selected from the group consisting of compounds represented by formulas (8) to (10). This is because a higher effect can be obtained when used together with the above-described lithium hexafluorophosphate or the like. In addition, R33 demonstrated in Formula (8) may be the same, and may differ. The same applies to R41 to R43 described in formula (9) and R51 and R52 described in formula (10).

（Ｘ３１は長周期型周期表における１族元素あるいは２族元素、またはアルミニウム（Ａｌ）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 (Al). M31 is a transition metal element, or a group 13 element, group 14 element, or group 15 element in the long-period periodic table. R31 is a halogen group, Y31 is — (O═) C—R32—C (═O) —, — (O═) C—C (R33) ₂ — or — (O═) C—C ( ═O) —, wherein R32 is an alkylene group, a halogenated alkylene group, an arylene group or a halogenated arylene group, and R33 is an alkyl group, a halogenated alkyl group, an aryl group or a halogenated aryl group. A3 is an integer of 1 to 4, b3 is 0, 2 or 4, and c3, d3, m3 and n3 are integers of 1 to 3.)

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

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

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

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

  Examples of the compound represented by formula (8) include compounds represented by formula (8-1) to formula (8-6). Examples of the compound represented by the formula (9) include compounds represented by the formula (9-1) to the formula (9-8). Examples of the compound represented by the formula (10) include a compound represented by the formula (10-1). In addition, if it is a compound which has a structure shown to Formula (8)-Formula (10), Formula (8-1)-Formula (8-6), Formula (9-1)-Formula (9-8), And it cannot be overemphasized that it is not limited to the compound shown to Formula (10-1).

  Moreover, it is preferable that electrolyte salt contains at least 1 sort (s) of the group which consists of a compound represented by Formula (11)-Formula (13). This is because a higher effect can be obtained when used together with the above-described lithium hexafluorophosphate or the like. In addition, m and n demonstrated in Formula (11) may be the same, and may differ. The same applies to p, q and r described in the equation (13).

（ｍおよびｎは１以上の整数である。）

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

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

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

（ｐ、ｑおよびｒは１以上の整数である。）

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

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

  Examples of the cyclic compound represented by Formula (12) include a series of compounds represented by Formula (12-1) to Formula (12-4). That is, 1,2-perfluoroethanedisulfonylimide lithium of formula (12-1), 1,3-perfluoropropane disulfonylimide lithium of formula (12-2), 1,3 of formula (12-3) -Perfluorobutane disulfonylimide lithium, 1,4-perfluorobutane disulfonylimide lithium of the formula (12-4), and the like. These may be single and multiple types may be mixed. Among these, 1,3-perfluoropropane disulfonylimide lithium is preferable. This is because a high effect can be obtained.

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

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

  In the secondary battery, when charged, for example, lithium ions are extracted 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, when discharging is performed, for example, lithium ions are released from the negative electrode 22 and inserted into the positive electrode 21 through the electrolytic solution impregnated in the separator 23.

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

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

  Further, the negative electrode 22 is manufactured by forming the negative electrode active material layer 22B and the coating 22C on both surfaces of the negative electrode current collector 22A by the same procedure as the above-described negative electrode manufacturing procedure.

  The secondary battery is assembled as follows. First, the positive electrode lead 25 is attached to the positive electrode current collector 21A by welding or the like, and the negative electrode lead 26 is attached to the negative electrode current collector 22A by welding or the like. Subsequently, after the positive electrode 21 and the negative electrode 22 are stacked and wound through the separator 23 to produce the wound electrode body 20, the center pin 24 is inserted into the winding center. Subsequently, the wound electrode body 20 is housed in the battery can 11 while being sandwiched between the pair of insulating plates 12 and 13, the tip of the positive electrode lead 25 is welded to the safety valve mechanism 15, and the tip of the negative electrode lead 26 is attached. Weld to battery can 11. Subsequently, the electrolytic solution described above is injected into the battery can 11 and impregnated in the separator 23. Finally, the battery lid 14, the safety valve mechanism 15, and the heat sensitive resistance element 16 are fixed to the opening end of the battery can 11 by caulking through the gasket 17. Thereby, the secondary battery shown in FIGS. 6 and 7 is completed.

  According to this cylindrical secondary battery, since the negative electrode 22 has the same configuration as the above-described negative electrode, the chemical stability of the negative electrode 22 is improved. Thereby, lithium ions are easily occluded and released in the negative electrode 22, and decomposition of the electrolytic solution is suppressed, so that cycle characteristics can be improved.

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

  Further, the electrolyte salt of the electrolyte includes lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, compounds represented by formulas (8) to (10), and a formula If at least one of the compounds represented by (11) to (13) is contained, a higher effect can be obtained.

  Other effects relating to the secondary battery and the manufacturing method thereof are the same as those of the above-described negative electrode.

[(1-2) Second Secondary Battery]
FIG. 8 shows an exploded perspective configuration of the second secondary battery, FIG. 9 shows an enlarged cross section taken along line IX-IX of the spirally wound electrode body 30 shown in FIG. 8, and FIG. 9 shows an enlarged part of the spirally wound electrode body 30 shown in FIG.

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

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

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

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

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

  The wound electrode body 30 is wound after the positive electrode 33 and the negative electrode 34 are laminated via the separator 35 and the electrolyte layer 36, and the outermost peripheral portion thereof is protected by a protective tape 37.

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

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

  Examples of the polymer compound that holds the electrolytic solution include polyethylene oxide, a crosslinked polymer containing polyethylene oxide, or an ether polymer compound such as polypropylene oxide, or an acrylate compound such as polymethyl methacrylate, polyacrylic acid, or polymethacrylic acid. Alternatively, ester polymer compounds, polyvinylidene fluoride, copolymers of polyvinylidene fluoride and polyhexafluoropyrene, fluorine polymer compounds such as polytetrafluoroethylene or polyhexafluoropropylene, etc. Polyacrylonitrile, polyphosphazene, polysiloxane, polyvinyl acetate, polyvinyl alcohol, styrene-butadiene rubber, nitrile-butadiene rubber, polystyrene, or polycarbonate Etc., and the like. These may be single and multiple types may be mixed. Among these, as the polymer compound, a fluorine polymer compound such as polyvinylidene fluoride is preferable. This is because it has high redox stability and 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, the solvent in this case is not only a liquid solvent but also a broad concept including those having ion conductivity capable of dissociating the electrolyte salt. Accordingly, when a polymer compound having ion conductivity is used, the polymer compound is also included in the solvent.

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

  In this secondary battery, lithium ions are occluded and released between the positive electrode 33 and the negative electrode 34 as in the first battery. That is, when charged, for example, lithium ions are released from the positive electrode 33 and inserted into the negative electrode 34 through the electrolyte layer 36. On the other hand, when discharging is performed, for example, lithium ions are released from the negative electrode 34 and inserted into the positive electrode 33 through the electrolyte layer 36.

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

  In the first manufacturing method, first, the positive electrode active material layer 33B is formed on both surfaces of the positive electrode current collector 33A by, for example, a procedure similar to the procedure for manufacturing the positive electrode 21 in the first secondary battery described above. 33 is produced. Further, for example, the negative electrode 34 is manufactured by forming the negative electrode active material layer 34B and the coating 34C on both surfaces of the negative electrode current collector 34A by the same procedure as the negative electrode 22 in the first secondary battery. Subsequently, a precursor solution containing an electrolytic solution, a polymer compound that holds the electrolytic solution, and a solvent is prepared and applied to the positive electrode 33 and the negative electrode 34, and then the solvent is volatilized to form the gel electrolyte layer 36. . Subsequently, the positive electrode lead 31 is attached to the positive electrode 33 and the negative electrode lead 32 is attached to the negative electrode 34. Subsequently, the positive electrode 33 and the negative electrode 34 on which the electrolyte layer 36 is formed are stacked via the separator 35 and then wound in the longitudinal direction, and a protective tape 37 is adhered to the outermost peripheral portion thereof to form the wound electrode body 30. Make it. Finally, for example, after the wound electrode body 30 is sandwiched between two film-shaped exterior members 40, the outer edge portions of the exterior member 40 are bonded to each other by heat fusion or the like, so that the wound electrode body 30 is Encapsulate. At this time, the adhesion film 41 is inserted between the positive electrode lead 31 and the negative electrode lead 32 and the exterior member 40. Thereby, the secondary battery shown in FIGS. 8 to 10 is completed.

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

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

  In the third manufacturing method, the swollenness of the secondary battery is suppressed as compared with the first manufacturing method. Further, in the third manufacturing method, compared to the second manufacturing method, the monomer or solvent that is a raw material of the polymer compound hardly remains in the electrolyte layer 36, and the polymer compound forming process is excellent. Be controlled. For this reason, sufficient adhesion is obtained between the positive electrode 33, the negative electrode 34 and the separator 35 and the electrolyte layer 36.

  According to this laminated film type secondary battery, since the negative electrode 34 has the same configuration as the above-described negative electrode, cycle characteristics can be improved. The effects of the secondary battery other than those described above are the same as those of the first secondary battery.

<2. Second Embodiment>
FIG. 11 shows a configuration of the negative electrode according to the second embodiment of the present invention, and shows a cross-sectional configuration corresponding to FIG.

  In the negative electrode in the first embodiment, the coating 3 containing the polyamide compound described above is provided on the negative electrode active material layer 2. However, in the negative electrode in the present embodiment, the negative electrode active material layer 2 contains a polyamide compound. It is out. That is, the negative electrode of the present embodiment has the same configuration as the negative electrode of the first embodiment, except that the negative electrode active material layer 2 contains the above-described polyamide compound instead of providing the coating 3.

  The negative electrode active material layer 2 includes a negative electrode material that can occlude and release the above-described lithium ions as a negative electrode active material and has at least one of silicon and tin as a constituent element, and the above-described polyamide compound. It is out. The negative electrode active material layer 2 may contain other materials such as a conductive agent or a binder as necessary.

  As long as this polyamide compound is contained in the negative electrode active material layer 2, its inclusion form is arbitrary. Among them, it is preferable that the negative electrode active material layer 2 is dispersed with high uniformity, and it is particularly preferable that the negative electrode active material particles are contained so as to cover the surface thereof. This is because when the negative electrode active material particles occlude and release lithium ions, for example, the reaction with other substances such as an electrolyte is more effectively suppressed. The negative electrode active material particles coated with the polyamide compound can be obtained, for example, by immersing the negative electrode active material particles in a solution containing the above-described polyamide compound, and then lifting and drying.

  This negative electrode is manufactured, for example, by the following procedure.

  Negative electrode active material layers 2 are formed on both surfaces of the negative electrode current collector 1. In the case of forming the negative electrode active material layer 2, first, for example, a negative electrode mixture obtained by mixing a powder of a negative electrode active material, the above-described polyamide compound, a conductive agent, and a binder is dispersed in a solvent. A paste-like negative electrode mixture slurry is prepared. Next, the negative electrode mixture slurry is applied to the negative electrode current collector 1 and dried, and then compression molded to form the negative electrode active material layer 2. Thereby, the negative electrode shown in FIG. 11 is completed.

  According to this negative electrode, the negative electrode active material layer 2 includes the above-described polyamide compound together with the negative electrode active material containing at least one of silicon and tin as a constituent element. Thereby, for example, chemical stability is improved as compared with a case where the polyamide compound is not included or a case where a carbon material is included as the negative electrode active material. Therefore, when this negative electrode is used in an electrochemical device such as a secondary battery, lithium ions are efficiently occluded and released in the negative electrode. In addition, in this case, the negative electrode becomes difficult to react with other substances (for example, an electrolyte in the secondary battery). For this reason, it can contribute to the improvement of cycling characteristics. Other effects relating to the negative electrode are the same as those of the negative electrode in the first embodiment.

  The negative electrode in the present embodiment is used, for example, in the same manner as the negative electrode in the first embodiment, taking a secondary battery as an example of an electrochemical device.

[(2-1) Third Secondary Battery]
FIG. 12 shows a configuration of the third secondary battery, and shows a cross-sectional configuration corresponding to FIG. The third secondary battery has the same configuration as that of the first secondary battery except that, for example, the negative electrode active material layer 22B includes the above-described polyamide compound instead of the negative electrode 22 having the coating 22C. Yes.

  The negative electrode 22 has the same configuration as the negative electrode in the second embodiment. For example, the negative electrode active material layer 22B is provided on both surfaces of the negative electrode current collector 22A. The negative electrode active material layer 22B includes a polyamide compound together with the negative electrode material described above.

  This secondary battery is the same as the negative electrode in the second embodiment, except that the negative electrode active material layer 22B containing a polyamide compound is formed on both surfaces of the negative electrode current collector 22A to produce the negative electrode 22. Manufactured in the same procedure as the first secondary battery.

  According to the third secondary battery, the negative electrode active material layer 22B includes the above-described polyamide compound together with the negative electrode active material containing at least one of silicon and tin as a constituent element. Thereby, for example, the chemical stability of the negative electrode 22 is improved as compared with a case where the polyamide compound is not included or a case where a carbon material is included as the negative electrode active material. Therefore, cycle characteristics can be improved. Other effects relating to the third secondary battery are the same as those described for the first secondary battery.

[(2-2) Fourth Secondary Battery]
FIG. 13 shows a configuration of the fourth secondary battery, and shows a cross-sectional configuration corresponding to FIG. The fourth secondary battery has the same configuration as that of the second secondary battery except that, for example, the negative electrode active material layer 34B includes the above-described polyamide compound instead of the negative electrode 34 having the coating 34C. Yes.

  The negative electrode 34 has the same configuration as that of the negative electrode 22 in the third secondary battery. For example, the negative electrode current collector 34A is provided with a negative electrode active material layer 22B containing a polyamide compound on both surfaces. .

  This secondary battery is similar to the negative electrode 22 in the third secondary battery except that the negative electrode active material layer 34B containing a polyamide compound is formed on both surfaces of the negative electrode current collector 34A to produce the negative electrode 34. Manufactured in the same procedure as the above-described second secondary battery.

  According to the fourth secondary battery, the negative electrode active material layer 34B includes the above-described polyamide compound together with the negative electrode active material containing at least one of silicon and tin as a constituent element. Therefore, cycle characteristics can be improved by the same action as the above-described third secondary battery. Other effects relating to the fourth secondary battery are the same as those described for the third secondary battery.

  In the first and second embodiments, the case where the above-described polyamide compound is contained in the film on the negative electrode active material layer or in the negative electrode active material layer has been described. However, if the polyamide compound is contained in the negative electrode, the location and form of the polyamide compound are not limited to the above embodiment. For example, both the negative electrode active material layer and the coating provided thereon may contain a polyamide compound.

  Examples of the present invention will be described in detail.

(Experimental Examples 1-1 to 1-12)
The laminate film type secondary battery shown in FIGS. 8 to 10 was produced by the following procedure. At this time, a lithium ion secondary battery in which the capacity of the negative electrode 34 is expressed based on insertion and extraction of lithium ions was made.

First, the positive electrode 33 was produced. First, lithium carbonate (Li ₂ CO ₃ ) and cobalt carbonate (CoCO ₃ ) are mixed at a molar ratio of 0.5: 1, and then calcined in air at 900 ° C. for 5 hours to form a lithium cobalt composite. An oxide (LiCoO ₂ ) was obtained. Subsequently, 91 parts by mass of lithium cobalt composite oxide as a positive electrode active material, 6 parts by mass of graphite as a conductive agent, and 3 parts by mass of polyvinylidene fluoride as a binder were mixed to obtain a positive electrode mixture. After that, 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 33A made of a strip-shaped aluminum foil (thickness = 12 μm) by a bar coater, dried, and then compression-molded by a roll press to perform positive electrode activation. A material layer 33B was formed.

  Next, the negative electrode 34 was produced. First, after preparing a negative electrode current collector 34A (thickness = 10 μm) made of a roughened electrolytic copper foil, silicon is deposited as a negative electrode active material on both surfaces of the negative electrode current collector 34A by an electron beam evaporation method. Thus, the negative electrode active material layer 34B was formed by forming a plurality of negative electrode active material particles. The thickness of the negative electrode active material layer 34B formed on one surface of the negative electrode current collector 34A was set to 6 μm. Subsequently, the content of the polymer compound having the structure shown in Formula (1) or Formula (2) as a polyamide compound having an alkali metal carboxylate is 3% by weight with respect to water as a solvent. Thus, an aqueous solution containing a polyamide compound was prepared. At this time, as the polymer compound having the structure represented by the formula (1), lithium poly-γ-glutamate which is a polymer compound having the structure represented by the formula (1-1) (Experimental Examples 1-1, 1- 5, 1-9), lithium poly-β-aspartate (Experimental Examples 1-2, 1-6, 1-10) and Formula (1) which are polymer compounds having the structure shown in Formula (1-2) 3) Sodium poly-γ-glutamate (Experimental Examples 1-3, 1-7, 1-11) which is a polymer compound shown in 3) was used. In addition, poly (dilithium amic acid), which is a polymer compound having the structure shown in Formula (2-1), was used as the polymer compound having the structure shown in Formula (2) (Experimental Examples 1-4, 1-8, 1-12). Finally, the negative electrode current collector 34A on which the negative electrode active material layer 34B is formed is dipped in the solution for several seconds and then lifted, and then dried in a reduced pressure environment at 60 ° C., and the coating 34C is formed on the negative electrode active material layer 34B. Formed.

Next, the electrolytic solution was adjusted. First, the solvent was mixed so that the composition shown in Table 1 was obtained. In this case, ethylene carbonate (EC), propylene carbonate (PC), 4-fluoro-1,3-dioxolan-2-one (FEC), which is a cyclic carbonate having a halogen represented by the formula (4), is used as a solvent. ) Or 4,5-difluoro-1,3-dioxolan-2-one (DFEC) or diethyl carbonate (DEC). After that, lithium hexafluorophosphate (LiPF ₆ ) was dissolved as an electrolyte salt. In this case, the content of lithium hexafluorophosphate was 1 mol / kg with respect to the solvent.

  Finally, a secondary battery was assembled using the electrolytic solution together with the positive electrode 33 and the negative electrode 34. First, the positive electrode lead 31 made of aluminum was welded to one end of the positive electrode current collector 33A, and the negative electrode lead 32 made of nickel was welded to one end of the negative electrode current collector 34A. Subsequently, the positive electrode 33, a separator 35 (thickness = 25 μm) made of a microporous polypropylene film, and the negative electrode 34 were laminated in this order, and then wound in the longitudinal direction. After that, the winding end portion was fixed with a protective tape 37 made of an adhesive tape to form a wound body that was a precursor of the wound electrode body 30. Subsequently, a laminate film (total thickness = 100 μm) 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 sequentially from the outside. The wound body was sandwiched between the exterior members 40 made of After that, the outer edge portions excluding one side of the exterior member 40 were heat-sealed to form a bag, and the wound body was housed inside the bag. Subsequently, an electrolytic solution was injected from the opening of the exterior member 40 and impregnated in the separator 35 to produce the wound electrode body 30. Finally, the laminated film type secondary battery was completed by thermally sealing and sealing the opening of the exterior member 40 in a vacuum atmosphere. For this secondary battery, by adjusting the thickness of the positive electrode active material layer 33 </ b> B so that the charge / discharge capacity of the negative electrode 34 is larger than the charge / discharge capacity of the positive electrode 33, lithium metal is present on the negative electrode 34 during full charge. It was made not to precipitate.

(Experimental example 1-13)
The same procedure as in Example 1-1, except that artificial graphite was used instead of silicon as the negative electrode active material, and the negative electrode active material layer 34B was formed to have a thickness of 65 μm on one side using a coating method. It went through. When forming this negative electrode active material layer 34B, 97 parts by mass of artificial graphite powder as a negative electrode active material and 3 parts by mass of polyvinylidene fluoride as a binder were mixed to prepare a negative electrode mixture. This negative electrode mixture was dispersed in N-methyl-2-pyrrolidone to form a paste-like negative electrode mixture slurry, which was uniformly applied to both surfaces of the negative electrode current collector 34A made of copper foil (thickness = 15 μm) by a bar coater. After drying, it was compression molded by a roll press. Also in this case, lithium metal is not deposited on the negative electrode 34 at full charge by adjusting the thickness of the positive electrode active material layer 33B so that the charge / discharge capacity of the negative electrode 34 is larger than the charge / discharge capacity of the positive electrode 33. I did it.

(Experimental Examples 1-14 to 1-17)
A procedure similar to that of Experimental Examples 1-1, 1-5, 1-9, and 1-13 was performed except that the coating 34C was not formed.

  When the cycle characteristics of the secondary batteries of Examples 1-1 to 1-17 were examined, the results shown in Table 1 were obtained.

When examining the cycle characteristics, charging and discharging was performed for 2 cycles in an atmosphere at 23 ° C., and the discharge capacity was measured. Subsequently, charging and discharging were performed in the same atmosphere until the total number of cycles reached 100 cycles, and the discharge capacity was measured. . From these discharge capacities, discharge capacity retention ratio (%) = (discharge capacity at the 100th cycle / discharge capacity at the second cycle) × 100 was calculated. In this case, the charge / discharge conditions for one cycle are charging at a constant current density of 1 mA / cm ² until the battery voltage reaches 4.2 V, and at a constant voltage of 4.2 V, the current density is 0.02 mA / cm ^2. The battery was charged until Thereafter, the battery was discharged at a constant current density of 1 mA / cm ² until the battery voltage reached 2.5V.

  The procedure and conditions for examining the cycle characteristics described above are the same for the series of experimental examples that follow.

  As shown in Table 1, Experimental Examples 1-1 to 1-13 in which a coating 34C containing poly-γ- lithium glutamate having the structure represented by Formula (1-1) was formed on the negative electrode active material layer 34B. Then, the discharge capacity maintenance rate became higher than Experimental Examples 1-14 to 1-17 in which it was not formed.

  Further, in Example 1-1 using silicon (electron beam evaporation method) as the negative electrode active material and using poly-γ- lithium glutamate having the structure represented by Formula (1-1), the polymer compound is not used. Further, the discharge capacity retention rate was about 30% higher than that of Experimental Example 1-14. On the other hand, in Example 1-13 using artificial graphite (coating method) as the negative electrode active material and using lithium poly-γ-glutamate, the discharge capacity was maintained more than in Example 1-17 without using the compound. The rate increased by only about 3%. That is, the increase rate of the discharge capacity retention rate was larger when silicon was used than when the carbon material was used as the negative electrode active material.

  These results represent the following. That is, the chemical stability of the negative electrode is improved without depending on the type of the negative electrode active material by forming a film containing poly-γ- lithium glutamate or the like. Therefore, at the time of charging / discharging, lithium ions are easily occluded and released in the negative electrode 34, and the electrolytic solution is hardly decomposed. On the other hand, when silicon that is advantageous for increasing the capacity is used as the negative electrode active material without forming a film, the electrolyte is more easily decomposed than when a carbon material (artificial graphite) is used. However, by forming the coating 34C containing poly-γ-glutamate lithium or the like, the chemical stability of the negative electrode is particularly improved when silicon is used as compared with the case where a carbon material is used as the negative electrode active material. Therefore, when the negative electrode uses silicon as the negative electrode active material and has the coating film 34, the effect of suppressing the decomposition of the electrolyte is remarkably exhibited.

  In this case, the following tendency was observed. That is, in the case where an aliphatic compound (a polymer compound having a structure represented by Formula (1-1) or Formula (1-2)) is used as a polyamide compound (Experimental Examples 1-1 and 1-2), the discharge capacity The maintenance rate was particularly high. Further, in the case of using a polyamide compound having a lithium carboxylate base (Experimental Example 1-1), the discharge capacity retention rate is higher than in the case of using a polyamide compound having a sodium carboxylate base (Experimental Example 1-3). became.

  Moreover, in Experimental Examples 1-5 to 1-12 in which FEC or the like was added as a solvent, the discharge capacity retention ratio was higher than in Experimental Examples 1-1 to 1-5 in which it was not added. In particular, the discharge capacity retention rate was higher in the case where DFEC was added (Experimental Examples 1-9 to 1-12) than in the case where it was not added (Experimental Examples 1-1 to 1-8).

  From these, in the secondary battery of the present invention, the following was confirmed when silicon was used as the negative electrode active material and the negative electrode active material layer 34B was formed using the vapor phase method. That is, in the secondary battery, a coating 34C containing a polyamide compound having a carboxylic acid alkali metal base is provided on the negative electrode active material layer 34B. Thereby, the cycle characteristics are improved without depending on the composition of the solvent of the electrolyte. In this case, a higher effect can be obtained by using an aliphatic compound as the polyamide compound or a polyamide compound having a lithium carboxylate base. Furthermore, if the cyclic carbonate having a halogen shown in Formula (4) is used as the solvent for the electrolyte, the cycle characteristics are further improved.

(Experimental examples 2-1 to 2-8)
A procedure similar to that of Experimental Example 1-5 was performed except that the composition of the electrolytic solution was changed to the composition shown in Table 2. Specifically, in Experimental Example 2-1, vinylene carbonate (VC), which is a cyclic carbonate having an unsaturated carbon bond shown in Formula (5), was added as a solvent, and the content of VC in the solvent was 1 weight. %. Similarly, in Experimental Examples 2-2 to 2-4, propene sultone (PRS) as a sultone, or succinic anhydride (SCAH) or an anhydrous 2-sulfobenzoic acid (SBAH) as an acid anhydride was added as a solvent. It was. In Experimental Example 2-5, lithium tetrafluoroborate (LiBF ₄ ) was added as an electrolyte salt, the concentration of LiPF ₆ in the electrolytic solution was 0.9 mol / kg, and the concentration of LiBF ₄ was 0.1 mol / kg. kg. In the same manner, in Experimental Examples 2-6 to 2-8, the compound represented by formula (8-6), which is the compound represented by formula (8), formula (11) or formula (12), bis (trifluoro) Lomomethanesulfonyl) imidolithium (LiTFSI) or the compound shown in formula (12-2) was added.

(Experimental Examples 2-9 to 2-16)
Except that the coating 34C was not formed, the same procedure as in Experimental Examples 2-1 to 2-8 was performed.

  When the cycle characteristics of the secondary batteries of Experimental Examples 2-1 to 2-16 were examined, the results shown in Table 2 were obtained.

As shown in Table 2, the same results as in Table 1 were obtained when VC or the like was added as the solvent of the electrolytic solution, or LiBF ₄ or the like was added as the electrolyte salt. That is, in Experimental Examples 2-1 to 2-8 in which the coating 34C containing poly-γ-glutamic acid lithium having the structure represented by Formula (1-1) was formed, Experimental Examples 2-9 to 2-9 in which the coating was not formed The discharge capacity retention rate was higher than 2-16.

In this case, in Experimental Examples 2-1 to 2-4 in which VC or the like was added as a solvent and in Experimental Examples 2-5 to 2-8 in which LiBF ₄ or the like was added as an electrolyte salt, none of them was added. Compared with Example 1-5, the discharge capacity maintenance rate became high.

  From these, in the secondary battery of the present invention, the following was confirmed when silicon was used as the negative electrode active material and the negative electrode active material layer 34B was formed using the vapor phase method. That is, in the secondary battery, a coating 34C containing a polyamide compound having a carboxylic acid alkali metal base is provided on the negative electrode active material layer 34B. Thereby, even when the composition of the electrolyte solvent or the composition of the electrolyte salt is changed, the cycle characteristics are improved. In this case, if the cyclic carbonate, sultone or acid anhydride having an unsaturated carbon bond shown in Formula (5) is used as the solvent of the electrolytic solution, a higher effect can be obtained. Further, when an electrolyte salt used is lithium tetrafluoroborate, a compound represented by formula (8), formula (11) or formula (12), a higher effect can be obtained.

(Experimental examples 3-1 to 3-3)
In the case of forming the negative electrode active material layer 34B, after forming a plurality of negative electrode active material particles, as shown in Table 3, except that an oxide-containing film and a metal material were formed, Experimental Example 1-5 and A similar procedure was followed. In the case of forming an oxide-containing film, silicon oxide (SiO ₂ ) was deposited as an oxide-containing film on the surface of the negative electrode active material particles by a liquid phase deposition method. Specifically, the negative electrode current collector 34A on which the negative electrode active material particles are formed is immersed in a solution in which boron as an anion scavenger is dissolved in silicofluoric acid for 3 hours, and silicon is deposited on the surface of the negative electrode active material particles. After the oxide was precipitated, it was washed with water and dried under reduced pressure. In the case of forming a metal material, a cobalt plating film was grown as a metal material by an electrolytic plating method. In detail, electricity was supplied while supplying air to the plating bath, and cobalt was deposited on the surface of the negative electrode current collector 34A. At this time, a cobalt plating solution manufactured by Japan High Purity Chemical Co., Ltd. was used as the plating solution, the current density was 2 A / dm ^{2 to} 5 A / dm ² , and the plating rate was 10 nm / second.

(Experimental examples 3-4 to 3-6)
A procedure similar to that of Experimental Examples 3-1 to 3-3 was performed, except that the coating 34C was not formed.

  When the cycle characteristics of the secondary batteries of Examples 3-1 to 3-6 were examined, the results shown in Table 3 were obtained.

  As shown in Table 3, even when an oxide-containing film or a metal material was formed before the formation of the coating 34C, the same results as those in Table 1 were obtained. That is, in Experimental Examples 3-1 to 3-3 in which the coating 34C containing lithium poly-γ-glutamate having the structure represented by Formula (1-1) was formed, Experimental Examples 3-4 to 3-3 in which it was not formed The discharge capacity maintenance rate became higher than 3-6.

  In this case, in Experimental Examples 3-1 to 3-3 in which the oxide-containing film or the metal material was formed, the discharge capacity retention rate was higher than in Experimental Example 1-5 in which they were not formed. In this case, the comparison between Experimental Examples 3-1 to 3-3 shows that the discharge capacity retention rate tends to be higher when both are formed than when only one of the oxide-containing film and the metal material is formed. It was.

  From these, in the secondary battery of the present invention, the following was confirmed when silicon was used as the negative electrode active material and the negative electrode active material layer 34B was formed using the vapor phase method. That is, in the secondary battery, a coating 34C containing a polyamide compound having a carboxylic acid alkali metal base is provided on the negative electrode active material layer 34B. Thereby, even when the configuration of the negative electrode active material layer 34B is changed, the cycle characteristics are improved. In this case, if an oxide-containing film or a metal material is formed before the formation of the coating 34C, the cycle characteristics are further improved. In particular, when an oxide-containing film or a metal material is used, the cycle characteristics are higher in both of the oxide-containing film and the metal material.

(Experimental examples 4-1 to 4-5)
Experimental Example 1-1 to 1- 1 except that the negative electrode active material layer 34B was formed so as to have a thickness of one side of 20 μm by using a sintering method instead of the vapor phase method (electron beam evaporation method). The same procedure as 4,1-14 was performed. In the case of forming the negative electrode active material layer 34B, a negative electrode mixture in which 95 parts by mass of silicon (average particle diameter (median diameter) = 1 μm) as a negative electrode active material and 5 parts by mass of polyimide as a binder is mixed. It was adjusted. Both surfaces of the negative electrode current collector 34A made of an electrolytic copper foil (thickness = 18 μm) roughened by a bar coater by dispersing this negative electrode mixture in N-methyl-2-pyrrolidone to form a paste-like negative electrode mixture slurry. It was uniformly applied to and dried. After that, it was compression molded by a roll press and heated in a vacuum atmosphere at 400 ° C. for 12 hours. Also in this case, lithium metal is not deposited on the negative electrode 34 at full charge by adjusting the thickness of the positive electrode active material layer 33B so that the charge / discharge capacity of the negative electrode 34 is larger than the charge / discharge capacity of the positive electrode 33. I did it.

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

  As shown in Table 4, when silicon was used as the negative electrode active material and the negative electrode active material layer 34B was formed using a sintering method, the same results as in Table 1 were obtained. That is, in Experimental Examples 4-1 to 4-4 and 1-13 in which the coating 34C including the poly-γ-glutamate lithium having the structure represented by the formula (1-1) was formed, an experiment in which the coating 34C was not formed The discharge capacity retention rate was higher than in Example 4-5. Further, the discharge capacity retention rate is increased in the case of using silicon (Experimental Examples 4-1 and 4-5) than in the case of using a carbon material as the negative electrode active material (Experimental examples 1-13 and 1-17). The rate has increased.

  In this case, the following tendency was observed. That is, in the case where an aliphatic compound (polymer compound having the structure shown in Formula (1-1) or Formula (1-2)) is used as the polyamide compound (Experimental Examples 4-1 and 4-2), Capacity maintenance rate became particularly high. Further, when the polyamide compound having a lithium carboxylate base is used (Experimental Example 4-1), the discharge capacity retention rate is higher than when the polyamide compound having a sodium carboxylate base is used (Experimental Example 4-3). It was.

  From these, in the secondary battery of the present invention, the following was confirmed when silicon was used as the negative electrode active material and the negative electrode active material layer 34B was formed using a sintering method. That is, in this secondary battery, the cycle characteristics are improved by providing the coating 34C containing the polyamide compound having a carboxylate alkali metal base on the negative electrode active material layer 34B.

(Experimental examples 5-1 to 5-4)
It replaced with the sintering method and passed through the procedure similar to Experimental example 4-1 to 4-4 except having formed the negative electrode active material layer 34B so that the thickness of one side might be set to 20 micrometers using the apply | coating method. . In the case of forming the negative electrode active material layer 34B, a negative electrode mixture in which 95 parts by mass of silicon (average particle diameter (median diameter) = 1 μm) as a negative electrode active material and 5 parts by mass of polyimide as a binder is mixed. It was adjusted. Both surfaces of the negative electrode current collector 34A made of an electrolytic copper foil (thickness = 18 μm) roughened by a bar coater by dispersing this negative electrode mixture in N-methyl-2-pyrrolidone to form a paste-like negative electrode mixture slurry. It was uniformly applied to and dried. After that, it was compression molded by a roll press. Also in this case, lithium metal is not deposited on the negative electrode 34 at full charge by adjusting the thickness of the positive electrode active material layer 33B so that the charge / discharge capacity of the negative electrode 34 is larger than the charge / discharge capacity of the positive electrode 33. I did it.

(Experimental Examples 5-5 to 5-8)
As shown in Table 5 for the negative electrode mixture without forming the coating 34C, the polymer having the structure shown in Formula (1-1) to Formula (1-3) or Formula (2-1) The same procedure as in Experimental Examples 5-1 to 5-4 was performed except that 0.5 part by mass of the compound was added. Also in this experimental example, as the polymer compound having the structure represented by formula (1-1) to formula (1-3) or formula (2-1), the structure represented by formula (1-1), respectively. Poly-γ-glutamate lithium having a structure shown in (Experimental Example 5-5), lithium poly-β-aspartate having the structure shown in Formula (1-2) (Experimental Example 5-6), and Formula (1-3) Poly- [gamma] -sodium glutamate having the structure shown (Experimental Example 5-7) or poly (dilithium amicate) having the structure shown in Formula (2-1) (Experimental Example 5-8) was used.

(Experimental Examples 5-9 to 5-16)
The same as Experimental Examples 5-1 to 5-8, except that the negative electrode active material layer 34B was formed using a SnCoC-containing material instead of silicon as the negative electrode active material so that the thickness on one side became 25 μm. Goed through the procedure. In the case of forming the negative electrode active material layer 34B, first, a tin-cobalt alloy powder and a carbon powder were mixed, and then a SnCoC-containing material was synthesized using a mechanochemical reaction. At this time, when the composition of the obtained SnCoC-containing material was analyzed, the tin content was 48% by mass, the cobalt content was 23% by mass, the carbon content was 20% by mass, and the total of tin and cobalt The ratio of cobalt to (Co / (Sn + Co)) was 32% by mass. When analyzing the composition of the SnCoC-containing material, the carbon content is measured using a carbon / sulfur analyzer, and the tin and cobalt content is measured by ICP (Inductively Coupled Plasma) emission analysis. And measured. Further, when the obtained SnCoC-containing material was subjected to X-ray diffraction analysis, a diffraction peak having a wide half-value width with a diffraction angle 2θ of 1.0 ° or more was observed between the diffraction angle 2θ = 20 ° to 50 °. . Subsequently, 80 parts by mass of SnCoC-containing material powder as a negative electrode active material, 12 parts by mass of graphite as a conductive agent, and 8 parts by mass of polyvinylidene fluoride as a binder were mixed to form a negative electrode mixture, and then N-methyl A paste-like negative electrode mixture slurry was prepared by dispersing in -2-pyrrolidone. Finally, the negative electrode mixture slurry was uniformly applied to the negative electrode current collector 34A made of copper foil (15 μm thick) and dried, followed by compression molding with a roll press. Also in this case, lithium metal is not deposited on the negative electrode 34 at full charge by adjusting the thickness of the positive electrode active material layer 33B so that the charge / discharge capacity of the negative electrode 34 is larger than the charge / discharge capacity of the positive electrode 33. I did it.

(Experimental Example 5-17)
Experimental Example 1-17, except that 0.5 parts by mass of lithium poly-γ-glutamate having the structure shown in Formula (1-1) was added to the negative electrode mixture without forming a film. A similar procedure was followed.

(Experimental Examples 5-18 and 5-19)
A procedure similar to that of Experimental Examples 5-1 and 5-9 was performed, except that the coating 34C was not formed.

  When the cycle characteristics of the secondary batteries of Examples 5-1 to 5-19 were examined, the results shown in Table 5 were obtained.

  As shown in Table 5, the film 34C or the negative electrode active material layer 34B containing silicon or SnCoC-containing material as the negative electrode active material and containing poly-γ- lithium glutamate having the structure shown in the formula (1-1) is used. Even when formed, the same results as those shown in Table 1 were obtained. That is, in Experimental Examples 5-1 to 5-17 and 1-13 in which the coating 34C including poly-γ-lithium glutamate and the like was formed, Experimental Examples 5-18, 5-19, 1- The discharge capacity retention rate was higher than 17.

  Also in this case, the increase rate of the discharge capacity retention rate was greater when silicon or SnCoC-containing material was used than when artificial graphite was used as the negative electrode active material. That is, in Examples 5-1, 5-5, 5-9, and 5-13, in which silicon or the like was used as the negative electrode active material and the coating 34C containing lithium poly-γ-glutamate was formed, it was not formed. The discharge capacity retention rate was increased by about 20% compared to Experimental Examples 5-18 and 5-19. On the other hand, in Experimental Examples 1-13 and 5-17 in which artificial graphite (coating method) was used as the negative electrode active material and a coating film containing lithium poly-γ-glutamate was formed, Experimental Examples in which it was not formed The discharge capacity retention rate increased by only 2% or 3% over 1-17.

  These results represent the following. That is, when the negative electrode 34 includes a polyamide compound such as poly-γ- lithium glutamate, the chemical stability of the negative electrode 34 is improved without depending on the location of the negative electrode 34. Even in this case, when the material containing silicon or tin is used as compared with the case where the carbon material is used as the negative electrode active material, the effect of suppressing the decomposition of the electrolyte is remarkably exhibited.

  Here, when attention is focused on the location where lithium poly-γ-glutamate or the like is contained, in Experimental Examples 5-1 to 5-4 and 5-9 to 5-12 included in the coating 34C, Experimental Example 5 included in the negative electrode active material layer 34B. The discharge capacity retention rate was higher than that of −5 to 5-8 and 5-13 to 5-16. That is, it was found that the chemical stability of the negative electrode is further improved when lithium poly-γ-glutamate or the like is contained as a film on the negative electrode active material layer than when contained in the negative electrode active material layer.

  In this case, the following tendency was observed. That is, when an aliphatic compound (polymer compound having a structure represented by Formula (1-1) or Formula (1-2)) is used as the polyamide compound, the discharge capacity retention rate is particularly high. Further, when a polyamide compound having a lithium carboxylate base (formula (1-1)) is used, the discharge capacity is maintained more than when a polyamide compound having a sodium carboxylate base (formula (1-3)) is used. The rate has increased.

  From these facts, in the secondary battery of the present invention, the following was confirmed when the negative electrode active material layer 34B was formed using a coating method while using silicon or SnCoC-containing material as the negative electrode active material. That is, when the negative electrode 34 includes a polyamide compound having an alkali metal carboxylate base, the cycle characteristics are improved without depending on the type of the negative electrode active material, the type of the polyamide compound, and the location of the polyamide compound. In this case, a higher effect can be obtained by providing the coating 34C containing the polyamide compound on the negative electrode active material layer 34B.

  Summarizing the results shown in Tables 1 to 5, the following was confirmed in the secondary battery of the present invention. That is, in the secondary battery of the present invention, the negative electrode includes a polyamide compound having an alkali metal carboxylate base together with a negative electrode active material containing at least one of silicon and tin as a constituent element. Thereby, cycle characteristics can be improved without depending on the composition of the electrolyte, the type of the negative electrode active material, the formation method of the negative electrode active material layer, or the like.

  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 an electrochemical device other than the secondary battery. Other applications include, for example, capacitors.

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

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

  In the above-described embodiments and examples, the case where the battery structure is a cylindrical type and the laminate film type and the case where the battery element has a winding structure have been described as examples. However, the present invention is not necessarily limited thereto. is not. The secondary battery of the present invention can be similarly applied to cases where other battery structures such as a square shape, a coin shape, and a button shape are provided, and where the battery element has other structures such as a laminated structure.

  In the above-described embodiments and examples, the case where lithium ions are used as the electrode reactant has been described. However, other group 1 elements such as sodium or potassium, group 2 elements such as magnesium or calcium, aluminum, and the like Other light metals may be used. In these cases, the negative electrode material described in the above embodiment can be used as the negative electrode active material.

It is sectional drawing showing the structure of the negative electrode which concerns on the 1st Embodiment of this invention. It is sectional drawing which expands and represents a part of negative electrode shown in FIG. It is sectional drawing showing the negative electrode of the reference example with respect to the negative electrode shown in FIG. 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 the 1st Embodiment of this invention. It is sectional drawing which expands and represents a part of winding electrode body shown in FIG. It is sectional drawing showing the structure of the 2nd secondary battery provided with the negative electrode which concerns on the 1st Embodiment of this invention. It is sectional drawing along the IX-IX line of the winding electrode body shown in FIG. FIG. 10 is an enlarged cross-sectional view illustrating a part of the spirally wound electrode body illustrated in FIG. 9. It is sectional drawing showing the structure of the negative electrode which concerns on the 2nd Embodiment of this invention. It is sectional drawing showing the structure of the principal part of the 3rd secondary battery provided with the negative electrode which concerns on the 2nd Embodiment of this invention. It is sectional drawing showing the structure of the principal part of the 4th secondary battery provided with the negative electrode which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

  1, 22A, 34A ... negative electrode current collector, 2, 22B, 34B ... negative electrode active material layer, 3, 22C, 34C ... coating, 11 ... battery can, 12, 13 ... insulating plate, 14 ... battery lid, 15 ... safety valve Mechanism, 15A ... disk plate, 16 ... heat resistance element, 17 ... gasket, 20, 30 ... wound electrode body, 21, 33 ... positive electrode, 21A, 33A ... positive electrode current collector, 21B, 33B ... positive electrode active material layer , 22, 34 ... negative electrode, 23, 35 ... separator, 24 ... center pin, 25, 31 ... positive electrode lead, 26, 32 ... negative electrode lead, 36 ... electrolyte layer, 37 ... protective tape, 40 ... exterior member, 41 ... adhesion Film, 201 ... negative electrode active material particles, 202 ... oxide-containing film, 204 (204A, 204B) ... gap, 205 ... gap, 206 ... metal material.

Claims (17)

A positive electrode including a positive electrode active material capable of occluding and releasing an electrode reactant;
A negative electrode active material capable of occluding and releasing the electrode reactant and having at least one of silicon (Si) and tin (Sn) as a constituent element, and a polyamide compound having a carboxylic acid alkali metal base A negative electrode,
A secondary battery comprising: a nonaqueous solvent and an electrolyte solution containing an electrolyte salt. The secondary battery according to claim 1, wherein the polyamide compound has the alkali metal carboxylate in a repeating unit. The secondary battery according to claim 1, wherein the electrode reactant is lithium ion, and the polyamide compound has a lithium carboxylate base. The secondary battery according to claim 1, wherein the polyamide compound has at least one of structures represented by formula (1) and formula (2).

(R1 is a trivalent saturated aliphatic hydrocarbon group, a trivalent unsaturated aliphatic hydrocarbon group, a trivalent group in which they are halogenated, or a trivalent group containing an alicyclic ring structure, or (It is a trivalent group containing an aromatic ring, M1 is an alkali metal element, and a1 is an integer of 1 or more.)

(R2 is a divalent saturated aliphatic hydrocarbon group, a divalent unsaturated aliphatic hydrocarbon group, a divalent group in which they are halogenated, or a divalent group or fragrance containing an alicyclic ring structure. R3 is a tetravalent saturated aliphatic hydrocarbon group, a tetravalent unsaturated aliphatic hydrocarbon group, a tetravalent group in which they are halogenated, or an alicyclic group. A tetravalent group containing a cyclic structure or a tetravalent group having an aromatic ring, M2 and M3 are alkali metal elements, and b1 is an integer of 1 or more.) The secondary battery according to claim 4, wherein the polyamide compound is an aliphatic compound having a structure represented by the formula (1). The structure represented by the formula (1) is at least one of the structures represented by the formulas (1-1) to (1-4), and the structure represented by the formula (2) is represented by the formula The secondary battery according to claim 4, wherein the secondary battery has a structure represented by (2-1).

(A2 to a5 are integers of 1 or more.)

(B2 is an integer of 1 or more.) The polyamide compound is lithium poly-γ-glutamate having a structure represented by the formula (1-1) or lithium poly-β-aspartate having a structure represented by the formula (1-2). 6. The secondary battery according to 6. The secondary battery according to claim 1, wherein the negative electrode has a film on a negative electrode active material layer provided on a negative electrode current collector, and the film includes the polyamide compound. The negative electrode active material has a plurality of particles, the negative electrode active material layer includes an oxide-containing film that covers a surface of the negative electrode active material, and the oxide-containing film includes silicon oxide, germanium ( The secondary battery according to claim 8, comprising at least one of an oxide of Ge) and an oxide of tin. The negative electrode active material is in a plurality of particles, and the negative electrode active material layer includes a metal material that does not alloy with the electrode reactant in a gap inside the negative electrode active material layer, and the metal material includes iron (Fe), cobalt The secondary battery according to claim 8, comprising at least one of (Co), nickel (Ni), zinc (Zn), and copper (Cu). The secondary battery according to claim 8, wherein the negative electrode active material layer is formed by a vapor phase method. The secondary battery according to claim 1, wherein the negative electrode has a negative electrode active material layer provided on a negative electrode current collector, and the negative electrode active material layer includes the polyamide compound together with the negative electrode active material. The solvent is a chain carbonate having a halogen represented by the formula (3), a cyclic carbonate having a halogen represented by the formula (4), or an unsaturated represented by the formula (5) to the formula (7). The secondary battery according to claim 1, comprising at least one of a cyclic carbonate having a carbon bond, sultone, and an acid anhydride.

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

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

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

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

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

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

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

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

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

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

(P, q and r are integers of 1 or more.) A negative electrode active material capable of inserting and extracting an electrode reactant and having at least one of silicon and tin as a constituent element;
A negative electrode for a secondary battery comprising : a polyamide compound having an alkali metal carboxylate base. The negative electrode for a secondary battery according to claim 15, further comprising a coating film on a negative electrode active material layer including the negative electrode active material provided on a negative electrode current collector, wherein the coating film includes the polyamide compound. The negative electrode for a secondary battery according to claim 15, further comprising a negative electrode active material layer provided on a negative electrode current collector, wherein the negative electrode active material layer includes the polyamide compound together with the negative electrode active material.

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