KR20090107425A - Anode and secondary battery - Google Patents

Abstract

PURPOSE: An anode and a secondary battery are provided to improve cycle characteristics and initial charge and discharge characteristics and to prevent expansion and construction of a negative active material layer. CONSTITUTION: A secondary battery includes a cathode(21), an anode(22), and an electrolytic solution. The anode has an anode active material layer(22B) on an anode current collector(22A). The anode active material layer contains a crystalline anode active material having silicon as an element, and is linked to the anode current collector.

Description

Negative and Secondary Batteries {ANODE AND SECONDARY BATTERY}

The present invention relates to a negative electrode having a negative electrode active material layer on a negative electrode current collector and a secondary battery having the same.

In recent years, portable electronic devices such as a video camera, a mobile phone or a notebook personal computer have been widely used, and their miniaturization, weight reduction and long life are strongly demanded. In connection with this, development of a battery, especially the secondary battery which can obtain a high energy density lightly as a power source of a portable electronic device is progressing.

Among them, secondary batteries (so-called lithium ion secondary batteries) using lithium storage and release for charging and discharging reactions are greatly expected because energy density larger than lead batteries or nickel cadmium batteries can be obtained.

A lithium ion secondary battery is equipped with the electrolyte solution along with a cathode and an anode. The negative electrode has a negative electrode active material layer on the negative electrode current collector, and the negative electrode active material layer contains a negative electrode active material that contributes to the charge and discharge reaction.

As the negative electrode active material, a carbon material is widely used. However, in recent years, with the high performance and multifunctionality of portable electronic devices, further improvement of battery capacity is required, and therefore, the use of silicon instead of a carbon material is considered, because the theoretical capacity of silicon is considered. This is because (4199 mAh / g) is significantly larger than the theoretical capacity of graphite (372 mAh / g), and thus a significant improvement in battery capacity is expected.

When silicon is used as a negative electrode active material, the vapor deposition method is used as a formation method of a negative electrode active material layer. In the vapor deposition method, the negative electrode active material layer is connected to and integrated with the negative electrode current collector, which makes it difficult to expand and contract the negative electrode active material layer during charging and discharging. However, when silicon is deposited using the vapor deposition method, it is feared that the silicon film becomes amorphous (amorphous). In the amorphous silicon film, the physical properties tend to change over time, and the adhesion strength of the negative electrode active material layer to the negative electrode current collector tends to be lowered under the influence of oxidation, and thus cycle characteristics and charge / discharge characteristics, which are important characteristics of the secondary battery, are reduced. Etc. may fall.

In addition, several techniques have already been proposed regarding the use of silicon as a negative electrode active material. Specifically, regarding the composition of the negative electrode active material, a technique of using a negative electrode active material having a transition metal element as a constituent element together with silicon is disclosed in, for example, Japanese Patent Laid-Open No. 2003-007295. Moreover, regarding the deposition method of a negative electrode active material, the technique which disperse | distributes the particle | grains which consists of silicon as a main component in airflow, and blows it out on the surface of a negative electrode electrical power collector, and deposits silicon, for example, Unexamined-Japanese-Patent No. 2005 -310502 is disclosed. Moreover, regarding the crystal state of a negative electrode active material, the technique using amorphous or microcrystalline silicon is disclosed by Unexamined-Japanese-Patent No. 2002-083594, for example, and crystallinity (Raman shift = 490 cm <^-1> -) 500㎝ ^-1 and a peak half value width = 10㎝ ^-1 to technology using silicon 30㎝ ^-1), for example, Japanese Patent Laid-Open Publication No. 2007-194207 discloses a call.

In recent years, portable electronic devices have become increasingly high in performance and multifunctional, and their power consumption tends to increase, so that the charge and discharge of secondary batteries are frequently repeated, and the cycle characteristics tend to be degraded. For this reason, the further improvement regarding the cycling characteristics of a secondary battery is desired. In this case, it is also important to improve the first charge-discharge characteristics in order to obtain excellent cycle characteristics.

This invention is made | formed in view of such a problem, and the objective is to provide the negative electrode, secondary battery which can improve cycling characteristics, and the first charge / discharge characteristic, and their manufacturing method.

According to an embodiment of the present invention, a negative electrode having a negative electrode active material layer is provided on a negative electrode current collector, wherein the negative electrode active material layer includes a crystalline negative electrode active material having silicon as a constituent element and is provided on the negative electrode current collector. It is connected. In addition, according to an embodiment of the present invention, a positive electrode; Negative electrode; And a secondary battery comprising an electrolyte solution, wherein the negative electrode has the above structure.

According to the negative electrode of the present invention, the negative electrode active material layer contains a crystalline negative electrode active material having silicon as a constituent element and is connected to the negative electrode current collector. In this case, compared with the case where the negative electrode active material is amorphous (amorphous) or when the negative electrode active material layer is not connected to the negative electrode current collector, the physical properties of the negative electrode active material are less likely to change with time, and the negative electrode at the time of electrode reaction It becomes difficult for the active material layer to expand and contract. Therefore, according to the secondary battery using the negative electrode of this invention, cycling characteristics and initial charge / discharge characteristics can be improved.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in detail with reference to drawings.

1 shows a cross-sectional configuration of a negative electrode according to one embodiment of the present invention. This negative electrode is used for electrochemical devices, such as a secondary battery, for example, and has the negative electrode collector 1 which has a pair of surface, and the negative electrode active material layer 2 provided in it.

It is preferable that the negative electrode electrical power collector 1 is comprised with the metal material which has favorable electrochemical stability, electrical conductivity, and mechanical strength. As such a metal material, copper, nickel, stainless steel, etc. are mentioned, for example, Especially, copper is preferable because high electrical conductivity is obtained.

In particular, it is preferable that the metal material has one or two or more metal elements which do not form an electrode reaction substance and an intermetallic compound as constituent elements. Forming an intermetallic compound with the electrode reactant material is influenced by the stress caused by expansion and contraction of the negative electrode active material layer 2 during operation of the electrochemical device (for example, during charging and discharging of a secondary battery). It is because there exists a possibility that electrical property may fall or the negative electrode active material layer 2 may peel from the negative electrode collector 1. As such a metal element, copper, nickel, titanium, iron, or chromium etc. are mentioned, for example.

Moreover, it is preferable that the metal material has 1 type, or 2 or more types of metal elements alloyed with the negative electrode active material layer 2 as a constitutent element. 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 off from the negative electrode current collector 1. As a metal element which does not form an electrode reaction substance and an intermetallic compound, and alloys with the negative electrode active material layer 2, for example, when the negative electrode active material layer 2 contains silicon as a negative electrode active material, it is copper, nickel Or iron. These metal elements are also preferable from a viewpoint of strength and electroconductivity.

The negative electrode current collector 1 may have either a single layer structure or a multilayer structure. When the negative electrode current collector 1 has a multilayer structure, for example, the layer adjacent to the negative electrode active material layer 2 is made of a metal material alloyed with it, and the non-adjacent layer is made of another metal material. It is preferred to be configured.

It is preferable that the surface of the negative electrode collector 1 is roughened. This is because adhesion between the negative electrode current collector 1 and the negative electrode active material layer 2 is improved by the so-called anchor effect. In this case, at least the surface of the negative electrode current collector 1 facing the negative electrode active material layer 2 may be roughened. As a method of roughening, the method of forming microparticles | fine-particles by electrolytic treatment, etc. are mentioned, for example. 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 cell. Copper foil produced using the electrolytic method is generally called "electrolytic copper foil." In addition, as a method of roughening, the method of sandblasting a rolled copper foil, etc. are mentioned, for example.

The ten-point average roughness Rz of the surface of the negative electrode current collector 1 is preferably 1.5 µm or more, more preferably 1.5 µm or more and 40 µm or less, further preferably 3 µm or more and 30 µm or less. This is because the adhesion between the negative electrode current collector 1 and the negative electrode active material layer 2 becomes higher. Specifically, when the ten-point average roughness Rz is smaller than 1.5 µm, sufficient adhesion may not be obtained. Moreover, when ten point average roughness Rz is larger than 40 micrometers, adhesiveness may fall rather.

The negative electrode active material layer 2 is formed by the spray method, for example. Specifically, the negative electrode active material layer 2 contains a crystalline negative electrode active material and is connected to the negative electrode current collector 1. "Connected to the negative electrode current collector 1" means an embodiment in which a crystalline negative electrode active material is directly formed (deposited) on the negative electrode current collector 1. Therefore, as a result of using a method other than the spray method (for example, a coating method or a sintering method), the negative electrode active material is indirectly connected to the negative electrode current collector 1 through another material (for example, a negative electrode binder), or Only that the negative electrode active material is adjacent to the surface of the negative electrode current collector 1 is not included in the above-described embodiment. The negative electrode active material layer 2 is connected to the negative electrode current collector 1 because the negative electrode active material layer 2 is physically fixed to the negative electrode current collector 1. 2) is difficult to expand and contract.

Whether or not the negative electrode active material is crystalline can be confirmed by, for example, X-ray diffraction. Specifically, when sharp peaks are observed by X-ray diffraction, the negative electrode active material has crystallinity.

In addition, the negative electrode active material layer 2 may be connected to the negative electrode current collector 1 at least in part. It is because the adhesive strength of the negative electrode active material layer 2 with respect to the negative electrode current collector 1 improves compared with the case where it is not connected at all, even if only one part is connected to the negative electrode current collector 1. When the negative electrode active material layer 2 is partly connected to the negative electrode current collector 1, the negative electrode active material layer 2 is in contact with the portion in contact with the negative electrode current collector 1 and the negative electrode current collector 1. You have a part that doesn't.

When the negative electrode active material layer 2 does not have a non-contact part, since the negative electrode active material layer 2 contacts the negative electrode collector 1 over the whole, the electron conductivity between both becomes high. On the other hand, since there is no unavoidable space (relaxation space) when the negative electrode active material layer 2 expands and contracts during electrode reaction, the negative electrode current collector 1 is affected by the stress at the time of expansion and contraction. ) May deform.

In contrast, in the case where the negative electrode active material layer 2 has a non-contact portion, there is a place to be avoided (relaxation space) when the negative electrode active material layer 2 expands and contracts at the time of electrode reaction. The negative electrode current collector 1 is hardly deformed under the influence of the stress at the time. On the other hand, since there is a part which does not contact between the negative electrode current collector 1 and the negative electrode active material layer 2, there exists a possibility that the electronic conductivity between both may become low.

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

It is preferable that the negative electrode active material layer 2 is alloyed at least one part of the interface with the negative electrode collector 1. This is because breakage of the negative electrode active material layer 2 is suppressed because the negative electrode active material layer 2 becomes difficult to expand and contract during the electrode reaction. This is because the electron conductivity is improved between the negative electrode current collector 1 and the negative electrode active material layer 2. This "alloying" includes not only the case where the constituent elements of the negative electrode current collector 1 and the constituent elements of the negative electrode active material layer 2 form a perfect alloy, but also the case where both constituent elements are in a mixed state. In this case, the constituent elements of the negative electrode current collector 1 may be diffused into the negative electrode active material layer 2 at both interfaces, and the constituent elements of the negative electrode active material layer 2 are diffused into the negative electrode current collector 1. May be present, and both constituent elements may be diffused.

This negative electrode active material layer 2 may have a single layer structure formed by one deposition process of the negative electrode active material, or may have a multilayer structure formed by a plurality of deposition processes. In this case, the negative electrode active material layer 2 may include a part having a multilayer structure in part. In addition, when high temperature is involved at the time of deposition, in order to suppress that the negative electrode collector 1 receives thermal damage, it is preferable that the negative electrode active material layer 2 has a multilayered structure. This is because, by dividing the deposition process of the negative electrode active material into a plurality of times, the time for exposing the negative electrode current collector 1 to high heat is shorter than when the deposition process is performed once.

Moreover, it is preferable that the negative electrode active material layer 2 has a space | gap inside. This is because the voids act as unavoidable points (relaxation spaces) when the negative electrode active material layer 2 expands and contracts during electrode reaction, and thus the negative electrode active material layer 2 becomes difficult to expand and contract.

The negative electrode active material is a negative electrode material capable of occluding and releasing an electrode reaction substance, and contains a material having silicon as a constituent element. This is because a high energy density can be obtained because the ability to occlude and release the electrode reactant is large. Such a material may be any one of silicon, an alloy, or a compound of silicon, and may have one or two or more of these phases in at least a part thereof. These may be individual or multiple types may be mixed.

In addition, in addition to what consists of 2 or more types of metal elements, the "alloy" in this invention includes the thing containing 1 or more types of metal elements and 1 or more types of semimetal elements. Of course, the alloy in this invention may contain the nonmetallic element. As the structure, a solid solution, a process (eutectic mixture), an intermetallic compound, or two or more thereof may coexist.

As an alloy of silicon, for example, as constituent elements other than silicon, tin (Sn), nickel, copper, iron, cobalt, manganese (Mn), zinc, indium (In), silver (Ag), titanium, germanium ( The thing which has at least 1 sort (s) of the crowd which consists of Ge), bismuth (Bi), antimony (Sb), and chromium is mentioned.

As a compound of silicon, what has oxygen and carbon (C), etc. are mentioned as a structural element other than silicon, for example. In addition, the compound of silicon may contain 1 type, or 2 or more types of series of elements demonstrated about the alloy of silicon as constituent elements other than silicon, for example.

This negative electrode active material is in the form of a plurality of particles. In this case, although the particulate negative electrode active material may have what kind of shape, it is preferable that at least one part of a negative electrode active material has a flat shape especially. This "flat" means having a long axis in the direction along the surface of the negative electrode current collector 1 and a shape having a short axis in the direction crossing the surface. This flat shape is a characteristic shown in the shape of a negative electrode active material, when the negative electrode active material layer 2 is formed using the spray method. When forming the negative electrode active material layer 2 using the spray method, when the melting temperature of the formation material is made high, there exists a tendency for a particulate negative electrode active material to become flat. When the plurality of particulate negative electrode active materials is flat, the negative electrode active materials overlap in the horizontal direction and are easily contacted (contact point increases), so that the electron conductivity in the negative electrode active material layer 2 is increased.

It is preferable that the half value width (2theta) of the diffraction peak in the (111) crystal plane of the negative electrode active material obtained by X-ray diffraction is 20 degrees or less, and it is more preferable that it is 0.6 degrees or more and 20 degrees or less. This is because the crystallinity of the negative electrode active material is secured.

The crystallite size resulting from the (111) crystal plane of the negative electrode active material obtained by X-ray diffraction is preferably 10 nm or more, more preferably 10 nm or more and 150 nm or less, more preferably 20 nm or more and 100 nm or less. More preferred. This is because the crystallinity of the negative electrode active material is ensured and the diffusibility of the electrode reaction substance (for example, lithium ions in the secondary battery) is improved during the electrode reaction. Specifically, when the crystallite size is smaller than 10 nm, there is a possibility that the diffusibility of the electrode reactant material is lowered. If the crystallite size is larger than 150 nm, it is difficult to suppress expansion and contraction of the negative electrode active material layer 2 at the time of electrode reaction, and the negative electrode active material may be cracked.

It is preferable that the negative electrode active material has oxygen as a constituent element. This is because expansion and contraction of the negative electrode active material layer 2 are suppressed. In this negative electrode active material layer 2, at least part of oxygen is preferably bonded to part of silicon. In this case, the bonding state may be silicon monoxide, silicon dioxide, or another metastable state.

It is preferable that content of oxygen in a negative electrode active material is 1.5 atomic% or more and 40 atomic% or less. This is because a higher effect can be obtained. Specifically, when the oxygen content is less than 1.5 atomic%, there is a possibility that the expansion and contraction of the negative electrode active material layer 2 may not be sufficiently suppressed. Moreover, when oxygen content is more than 40 atomic%, there exists a possibility that resistance may increase too much. In addition, when an anode is used together with electrolyte solution in an electrochemical device, the film etc. formed by the partial damage of the electrolyte solution shall not be included in a negative electrode active material. That is, when content of oxygen in a negative electrode active material is computed, oxygen in the said film is not included.

The negative electrode active material having oxygen can be formed, for example, by continuously introducing oxygen gas into the chamber when the negative electrode material is deposited. In particular, when the desired oxygen content cannot be obtained only by introducing oxygen gas, a liquid (for example, steam or the like) may be introduced into the chamber as a source of oxygen.

In addition, the negative electrode active material has an oxygen-containing region having oxygen in the thickness direction thereof, and the content of oxygen in the oxygen-containing region is preferably higher than the content of oxygen in the other region. . This is because expansion and contraction of the negative electrode active material layer 2 are suppressed. Regions other than this oxygen containing region may or may not have oxygen. Of course, in the case where regions other than the oxygen-containing region also have oxygen, it goes without saying that the oxygen content is lower than the oxygen content in the oxygen-containing region.

In this case, in order to further suppress the expansion and contraction of the negative electrode active material layer 2, a region other than the oxygen containing region also has oxygen, and the negative electrode active material has a first oxygen-containing region (a region having a lower oxygen content). ) And a second oxygen-containing region (region having a higher oxygen content) having a higher oxygen content. In this case, it is preferable that the second oxygen-containing region is sandwiched by the first oxygen-containing region, and it is more preferable that the first oxygen-containing region and the second oxygen-containing region are alternately repeated and stacked. Do. This is because a higher effect can be obtained. It is preferable that content of oxygen in a 1st oxygen containing area | region is as few as possible, and content of oxygen in a 2nd oxygen-containing area | region is content when the said negative electrode active material has oxygen, for example. Same as

The negative electrode active material having the first and second oxygen-containing regions is formed by intermittently introducing oxygen gas into the chamber or changing the amount of oxygen gas introduced into the chamber when the negative electrode material is deposited, for example. It is possible. Of course, when the desired oxygen content cannot be obtained only by introducing oxygen gas, a liquid (for example, water vapor or the like) may be introduced into the chamber.

In addition, the content of oxygen may or may not be clearly different between the first and second oxygen-containing regions. In particular, when the introduction amount of the oxygen gas described above is changed continuously, the content of oxygen may also be changed continuously. The first and second oxygen-containing regions become so-called "layers" when the amount of oxygen gas introduced is intermittently changed, while "layers" when the amount of oxygen gas introduced is continuously changed. Rather than being "layered". In the latter case, the content of oxygen is distributed while repeating the elevation in the negative electrode active material. In this case, it is preferable that the content of oxygen is changed stepwise or continuously between the first and second oxygen-containing regions. This is because if the oxygen content changes rapidly, the diffusivity of the ions may decrease or the resistance may increase.

In addition, the negative electrode active material comprises at least one metal element of a crowd consisting of iron, nickel, molybdenum, titanium, chromium, cobalt, copper, manganese, zinc, germanium, aluminum, zirconium, silver, tin, antimony and tungsten. It is preferable to have as. It is because the binding property of a negative electrode active material improves, the expansion and contraction of the negative electrode active material layer 2 are suppressed, and the resistance of a negative electrode active material falls. The content of the metal element in the negative electrode active material can be arbitrarily set. However, in the case where the negative electrode is used in the secondary battery, when the content of the metal element becomes too large, the negative electrode active material layer 2 must be thickened in order to obtain a desired battery capacity. There is a possibility to be peeled off from the whole 1 or to be separated.

The negative electrode active material having the metal element described above can be formed by, for example, using alloy particles as a forming material when depositing a negative electrode material using a spray method.

In addition, when a negative electrode active material has a metal element with silicon, the whole of the negative electrode active material layer 2 may have silicon and a metal element, and only a part may have silicon and a metal element.

As a case where a part of negative electrode active material has silicon and a metal element, the case where a part of particulate-form negative electrode active material has silicon and a metal element is mentioned, for example. In this case, the crystal state of the particulate negative electrode active material may be an alloy state in which a complete alloy is formed, or may be a compound state (phase separation state) in which silicon and a metal element are mixed without reaching a complete alloy. The crystal state of the negative electrode active material having a metal element with silicon can be confirmed by, for example, energy dispersive x-ray fluorescence spectroscopy (EDX).

In addition, the negative electrode active material layer 2 may include the part formed using the method other than the spray method, for example with the part formed using the spray method. As such another method, it is formed using, for example, a gas phase method, a liquid phase method, a coating method or a firing method, or two or more kinds thereof.

As the vapor phase method, for example, physical deposition or chemical deposition, specifically, vacuum deposition, sputtering, ion plating, laser ablation, chemical vapor deposition (CVD) or plasma chemical vapor deposition Etc. can be mentioned. As a liquid phase method, well-known methods, such as electroplating or electroless plating, can be used. The coating method is, for example, a method in which a particulate negative electrode active material is mixed with a binder or the like and then dispersed in a solvent and applied. The baking method is a method of heat-treating at a temperature higher than melting | fusing point, such as a binder, after apply | coating using the apply | coating method, for example. Also regarding a baking method, a well-known method can be used, For example, an atmospheric baking method, a reactive baking method, or a hot press baking method is mentioned.

In addition to the material having silicon as a constituent element, the negative electrode active material may contain other materials capable of occluding and releasing the electrode reaction substance. As such another material, for example, it is possible to occlude and release the electrode reaction substance, and to contain at least one of a metal element and a semimetal element as a constituent element (excluding materials having silicon as a constituent element). ). It is preferable to use such a material because a high energy density is obtained. The material may be a single element or an alloy of a metal element, a semimetal element, or a compound, or may have one or two or more phases thereof at least in part.

As said metal element or semimetal element, the metal element or semimetal element which can form an alloy with an electrode reaction substance is mentioned, for example. Specifically, magnesium (Mg), boron, aluminum, gallium (Ga), indium, germanium, tin, lead (Pb), bismuth, cadmium (Cd), silver, zinc, hafnium (Hf), zirconium (Zr), Yttrium (Y), palladium (Pd), platinum (Pt), and the like, and tin is preferred among them. This is because a high energy density can be obtained because the ability to occlude and release the electrode reactant is large. As a material containing tin, the material which has the single substance, alloy, or compound of tin, or at least one of those 1 type, or 2 or more types of phases is mentioned, for example.

As the alloy of tin, for example, at least one member of the group consisting of silicon, nickel, copper, iron, cobalt, manganese, zinc, indium, silver, titanium, germanium, bismuth, antimony and chromium as constituent elements other than tin And having one. As a compound of tin, what has oxygen or carbon as a structural element other than tin, etc. are mentioned, for example. In addition, the compound of tin may contain any 1 type, or 2 or more types of a series of elements demonstrated about the alloy of tin as constituent elements other than tin, for example. The alloys or compounds of tin examples, there may be mentioned SnSiO _3, LiSnO, or Mg ₂ Sn and the like.

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

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

This SnCoC containing material may have another structural element as needed. As other constituent elements, silicon, iron, nickel, chromium, indium, niobium, germanium, titanium, molybdenum, aluminum, phosphorus, gallium or bismuth is preferable, for example, and may have two or more of them. This is because a higher effect can be obtained.

In addition, 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 the electrode reactant, whereby excellent cycle characteristics can be obtained. The half width of the diffraction peak obtained by X-ray diffraction of the phase is 1.0 ° or more at the diffraction angle (2θ) when CuKα rays are used as specific X-rays and the insertion speed is 1 ° / min. It is preferable. This is because lithium is more easily occluded and released and the reactivity with the electrolyte is reduced.

Whether or not the diffraction peak obtained by X-ray diffraction corresponds to the reaction phase capable of reacting with lithium can be easily determined by comparing the X-ray diffraction charts before and after the electrochemical reaction with lithium. For example, if the position of the diffraction peak changes before and after the electrochemical reaction with lithium, it corresponds to the reaction phase capable of reacting with lithium. In this case, for example, a diffraction peak of a low crystalline or amorphous reaction phase is shown between 2θ = 20 ° to 50 °. This low crystalline or amorphous reaction phase contains each of the above-mentioned constituent elements, and is considered to be mainly low crystallized or amorphous by carbon.

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

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

As a measuring method of examining the bonding state of an element, X-ray photoelectron spectroscopy (XPS) is mentioned, for example. This XPS irradiates soft X-rays (Al-Kα rays or Mg-Kα rays in commercially available devices) to the surface of the sample, and measures the kinetic energy of photoelectrons that emanate from the surface of the sample. It is a method of examining the element composition of the several nm area | region from the surface, and the bonding state of an element.

The binding energy of the internal orbital electrons of the element changes approximately in relation to the charge density on the element. For example, when the charge density of a carbon element decreases due to interaction with an element present in the vicinity, since the outer electrons such as 2p electrons decrease, the 1s electron of the carbon element is a strong velocity from the angle. You will be impressed. In other words, when the charge density of the element decreases, the bond energy becomes high. In the XPS, when the binding energy is high, the peak is shifted to a high energy region.

In XPS, the peak of carbon's 1s orbital (C1s), at graphite, appears at 284.5 eV in an energy calibrated device such that the peak at 4f orbit (Au4f) of gold atoms is obtained at 84.0 eV. In addition, if the surface contamination carbon, it appears at 284.8eV. On the other hand, when the charge density of a carbon element becomes high, for example, when couple | bonding with a positive element than carbon, the peak of C1s appears in the area | region lower than 284.5 eV. That is, when at least a part of the carbon contained in the SnCoC-containing material is combined with a metal element or a semimetal element, which is another constituent element, the peak of the C1s synthesized wave obtained for the SnCoC-containing material appears in a region lower than 284.5 eV. .

In the case of XPS measurement, when the surface is covered with surface-contaminated carbon, it is preferable to lightly sputter the surface with an argon ion gun attached to the XPS apparatus. When the SnCoC-containing material to be measured exists in the negative electrode 22, the secondary battery may be disassembled to extract the negative electrode 22, and then washed with a volatile solvent such as dimethyl carbonate. This is for removing the low volatility solvent and electrolyte salt which exist on the surface of the negative electrode 22. It is preferable to perform these sampling in an activating atmosphere.

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

This SnCoC-containing material can be formed by, for example, dissolving a mixture in which raw materials of the respective constituent elements are mixed in an electric furnace, a high frequency induction furnace, an arc melting furnace, or the like and then solidifying. In addition, various atomization methods such as gas atomizing or water atomization, various roll methods, mechanical alloying methods, or mechanical milling methods (mechanical milling methods) A method using a mechanochemical reaction such as a milling method) may be used. Especially, the method of using a mechanochemical reaction is preferable. This is because the SnCoC-containing material becomes a low crystalline or amorphous structure. In the method using a mechanochemical reaction, a manufacturing apparatus, such as a planetary ball mill apparatus and an atliter, can be used, for example.

As a raw material, although the single substance of each structural element may be mixed and used, it is preferable to use an alloy about a part of structural elements other than carbon. This is because by adding carbon to such an alloy and synthesizing it by a method using a mechanical annealing method, a low crystallized or amorphous structure is obtained, and the reaction time is also shortened. In addition, powder may be sufficient as the form of a raw material, and may be a block shape.

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

Moreover, as another material which can occlude and discharge | release an electrode reaction substance, a carbon material is mentioned, for example. This carbon material is, for example, digraphitizable carbon, non-graphitizable carbon having a plane spacing of (002) plane of 0.37 nm or more, graphite having a plane spacing of (002) plane of 0.34 nm or less. More specifically, there are pyrolytic carbons, cokes, glassy carbon fibers, organic polymer compound fired bodies, activated carbon or carbon blacks. Among these, cokes include pitch coke, needle coke, petroleum coke, and the like. An organic high molecular compound calcined body means what carbonized the phenol resin, furan resin, etc. by baking at appropriate temperature. The carbon material is preferable because the change in crystal structure associated with occlusion and release of the electrode reaction substance is very small, and thus a high energy density can be obtained and also functions as a conductive agent. The shape of the carbon material may be any of fibrous, spherical, granular, or scale-like shapes.

Moreover, as another material which can occlude and discharge | release an electrode reaction substance, the metal oxide or high molecular compound which can occlude and release an electrode reaction substance, etc. are mentioned, for example. A metal oxide is iron oxide, ruthenium oxide, molybdenum oxide, etc., for example, and a high molecular compound is polyacetylene, polyaniline, polypyrrole, etc., for example.

Of course, the other material which can occlude and discharge | release an electrode reaction substance may be other than the above. In addition, 2 or more types of said series of negative electrode materials may be mixed by arbitrary combinations.

Here, with reference to A of FIG. 2, B of FIG. 4, the detailed structural example of a negative electrode is demonstrated. 2A to 4B show an enlarged portion of the negative electrode shown in FIG. 1, and A in each drawing is a scanning electron microscope (SEM) photograph (secondary electron image), B Is a schematic diagram of the SEM image shown in A. FIG. In addition, the case where single element of silicon was used as a negative electrode active material is shown by A and B of FIG. 2, and the case which used the thing containing metal element in silicon as a negative electrode active material is shown in FIG.

As described above, the negative electrode active material layer 2 is formed by depositing a material having silicon as a constituent element on the negative electrode current collector 1 using, for example, a spray method. The negative electrode active material contained in this negative electrode active material layer 2 has a plurality of particulate forms, that is, the negative electrode active material layer 2 has a plurality of negative electrode active material particles 201. In this case, as shown in FIG. 2A to FIG. 3B, the plurality of negative electrode active material particles 201 may have a multilayer structure in which they are stacked in the thickness direction of the negative electrode active material layer 2, or FIG. As shown to A and B of 4, the some negative electrode active material particle 201 may have a single layer structure arrange | positioned along the surface of the negative electrode electrical power collector 1.

For example, the negative electrode active material layer 2 is partially connected to the negative electrode current collector 1, and is in contact with the negative electrode current collector 1 (contact portion P1) and the negative electrode current collector 1. ) Has a portion (non-contact portion P2) that does not contact. In addition, the negative electrode active material layer 2 has a plurality of voids 2K therein.

A part of the negative electrode active material particles 201 is flat, for example. That is, the negative electrode active material layer 2 has some flat particles 201P as part of the plurality of negative electrode active material particles 201. The flat particles 201P are in contact with each other so as to overlap with the adjacent negative electrode active material particles 201.

In the case where the negative electrode active material particles 201 have a metal element together with silicon, for example, part of the negative electrode active material particles 201 has silicon and a metal element. In this case, the crystal state of the negative electrode active material particles 201 may be an alloy state (AP) or a compound (phase separation) state (SP). In addition, the crystal state of the negative electrode active material particle 201 which has only silicon and does not have a metal element is a single state MP.

Three crystal states (MP, AP, SP) of these negative electrode active material particles 201 are clearly shown in FIGS. 4A and 4B. That is, the negative electrode active material particles 201 in a single state MP are observed as uniform gray areas. The negative electrode active material particles 201 in the alloy state AP are observed as a uniform white region. The negative electrode active material particles 201 in the phase-separated state SP are observed as regions in which gray portions and white portions are mixed.

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

First, the negative electrode collector 1 which consists of roughened electrolytic copper foil etc. is prepared. Subsequently, after preparing the material which has silicon as a negative electrode active material, the above-mentioned material is deposited on the surface of the negative electrode current collector 1 using the spray method, and the negative electrode active material layer 2 is formed. In this spraying method, a material containing silicon is sprayed on the surface of the negative electrode current collector 1 in a molten state. When forming the negative electrode active material layer 2, it is preferable to use the particle | grains whose median diameter is 5 micrometers or more and 200 micrometers or less as a material which has silicon. This is because the particle size distribution of the negative electrode active material is optimized. This completes the negative electrode.

When forming the negative electrode active material layer 2 using the spray method, for example, by adjusting the melting temperature and cooling temperature of the material for forming the negative electrode active material layer 2, the diffraction peaks obtained by X-ray diffraction are obtained. The half value width 2θ and the crystallite size can be changed.

According to this negative electrode and its manufacturing method, the negative electrode active material layer 2 containing the negative electrode active material which has silicon as a structural element is formed on the negative electrode collector 1 using the spray method. For this reason, the negative electrode active material has crystallinity and the negative electrode active material layer 2 (crystalline negative electrode active material) is connected to the negative electrode current collector 1. In this case, compared with the case where the negative electrode active material is amorphous (amorphous) or when the negative electrode active material layer 2 is not connected to the negative electrode current collector 1, the physical properties of the negative electrode active material are less likely to change with time. At the time of electrode reaction, the negative electrode active material layer 2 becomes difficult to expand and contract. Therefore, it can contribute to the performance improvement of an electrochemical device. More specifically, when a negative electrode is used for a secondary battery, it can contribute to the improvement of cycling characteristics and initial charge / discharge characteristics.

In particular, the negative electrode active material layer 2 is alloyed at least in part of the interface with the negative electrode current collector 1, or the negative electrode active material layer 2 has voids therein, or the negative electrode active material layer 2 If it has a part which does not contact the negative electrode electrical power collector 1, a higher effect can be acquired.

In the case where the negative electrode active material has a plurality of particulates, a higher effect can be obtained if at least a part of the negative electrode active material is flat.

Moreover, the half value width (2theta) of the diffraction peak in the (111) crystal plane of the negative electrode active material obtained by X-ray diffraction is 20 degrees or less, or the crystallite size resulting from the (111) crystal plane of the negative electrode active material is 10 nm or more, Preferably, a higher effect can be obtained as it is 20 nm or more and 100 nm or less.

In addition, the negative electrode active material has oxygen as a constituent element, and the content of oxygen in the negative electrode active material is 1.5 atomic% or more and 40 atomic% or less, or the negative electrode active material has an oxygen-containing region containing oxygen in the thickness direction, The oxygen content in the oxygen-containing region is higher than the oxygen content in the other region, or the negative electrode active material is iron, nickel, molybdenum, titanium, chromium, cobalt, copper, manganese, zinc, germanium, Higher effects can be obtained by having, as a constituent element, at least one metal element of the group consisting of arminium, zirconium, silver, tin, antimony and tungsten.

In addition, if the surface of the negative electrode current collector 1 facing the negative electrode active material layer 2 is roughened, the adhesion between the negative electrode current collector 1 and the negative electrode active material layer 2 can be improved. In this case, when the 10-point average roughness Rz of the surface of the negative electrode current collector 1 is 1.5 µm or more, preferably 3 µm or more and 30 µm or less, a higher effect can be obtained.

Moreover, when forming the negative electrode active material layer 2 using the spray method, when a particle | grain with a median diameter of 5 micrometers or more and 200 micrometers or less is used as the formation material, a higher effect can be acquired.

Next, an example of use of the negative electrode described above will be described. Here, taking a secondary battery as an example of an electrochemical device, the above negative electrode is used for a secondary battery as follows.

(First secondary battery)

5 and 6 show a cross-sectional structure of the first secondary battery, and FIG. 6 shows a cross section along the line VI-VI shown in FIG. 5. The secondary battery described here is, for example, a lithium ion secondary battery whose capacity of the negative electrode 22 is displayed based on the occlusion and release of lithium which is an electrode reactant.

This secondary battery mainly contains the battery element 20 which has a flat winding structure inside the battery can 11.

The battery can 11 is a rectangular exterior member, for example. As shown in Fig. 6, the rectangular exterior member has a rectangular or roughly rectangular shape (including a curve in part) in a longitudinal direction, and has a rectangular rectangular battery. In addition, an oval rectangular battery is also constructed. That is, a rectangular exterior member is a bottomed rectangular or bottomed rectangular bowl-shaped member having an opening of a rectangular (elliptical) shape in which a rectangular shape or an arc is connected in a straight line. In FIG. 6, the case where the battery can 11 has a rectangular cross-sectional shape is shown. The battery structure containing this battery can 11 is called what is called a square.

The battery can 11 is made of, for example, metal material such as iron, aluminum, or an alloy thereof, and may have a function as an electrode terminal. In this case, iron which is harder than aluminum is preferable in order to suppress expansion of the secondary battery by using the rigidity (hard to deform) of the battery can 11 during charging and discharging. When the battery can 11 is made of iron, for example, plating of nickel or the like may be performed.

In addition, the battery can 11 has a hollow structure in which one end and the other end are closed and opened, respectively, and the insulating plate 12 and the battery cover 13 are attached to the open end and sealed. The insulating plate 12 is disposed perpendicularly to the winding main surface of the battery element 20 between the battery element 20 and the battery cover 13, and is made of, for example, polypropylene or the like. It is. The battery cover 13 is made of the same material as the battery can 11, for example, and may have a function as an electrode terminal in the same manner.

On the outside of the battery cover 13, a terminal plate 14 serving as a positive electrode terminal is provided, and the terminal plate 14 is electrically insulated from the battery cover 13 through the insulating case 16. This insulating case 16 is comprised by polybutylene terephthalate etc., for example. In addition, a through hole is provided in a substantially center of the battery cover 13, and the through hole is electrically connected to the terminal plate 14 and electrically insulated from the battery cover 13 through the gasket 17. The pin 15 is inserted. The gasket 17 is made of, for example, an insulating material, and asphalt is coated on the surface thereof.

The cleavage valve 18 and the injection hole 19 are provided in the vicinity of the periphery of the battery cover 13. The cleavage valve 18 is electrically connected to the battery cover 13, and is separated from the battery cover 13 when the internal pressure of the battery reaches a predetermined value due to an internal short circuit or heating from the outside. It is supposed to open. The injection hole 19 is blocked by the sealing member 19A which consists of stainless steel balls, for example.

The battery element 20 is obtained by stacking and winding the positive electrode 21 and the negative electrode 22 through the separator 23, and is flat in response to the shape of the battery can 11. A positive electrode lead 24 made of a metal material such as aluminum is attached to an end portion (for example, an inner surface end portion of the back surface) of the positive electrode 21, and nickel or the like is attached to an end portion (for example, an outer end portion) of the negative electrode 22. A negative electrode lead 25 made of a metal material is attached. The positive electrode lead 24 is welded to one end of the positive electrode pin 15 and electrically connected to the terminal plate 14, and the negative electrode lead 25 is welded to the battery can 11 and electrically connected.

The positive electrode 21 is provided with, for example, the positive electrode active material layer 21B on both surfaces of a positive electrode current collector 21A having a pair of faces. However, the positive electrode active material layer 21B may be provided only on one side of the positive electrode current collector 21A.

21 A of positive electrode electrical power collectors are comprised with metal materials, such as aluminum, nickel, or stainless steel, for example.

The positive electrode active material layer 21B contains, as a positive electrode active material, any one kind or two or more kinds of positive electrode materials capable of occluding and releasing lithium, and optionally, other materials such as a positive electrode binder and a positive electrode conductive agent. You may include it.

As a positive electrode material which can occlude and release lithium, a lithium containing compound is preferable, for example. This is because a high energy density can be obtained. As this lithium containing compound, the composite oxide containing lithium and a transition metal element, the phosphoric acid compound containing lithium and a transition metal element, etc. are mentioned, for example. Especially, it is preferable to contain at least 1 sort (s) of the group which consists of cobalt, nickel, manganese, and iron as a transition metal element. This is because a higher voltage can be obtained. The chemical formula is represented by Li _x M10 ₂ or Li _y M2PO ₄ , for example. In the formula, M1 and M2 represent one or more kinds of transition metal elements. The values of x and y differ from Ekfk in the state of charge and discharge, and are usually 0.05 ≦ x ≦ 1.10 and 0.05 ≦ y ≦ 1.10.

Examples of the composite oxide containing lithium and transition metal elements 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 manganese composite with a spinel structure Oxides (LiMn ₂ O ₄ ); and the like. Especially, the composite oxide containing cobalt is preferable. This is because a high capacity can be obtained and excellent cycle characteristics can also be obtained. Moreover, as a phosphate compound containing lithium and a transition metal element, a lithium iron phosphate compound (LiFePO ₄ ) or a lithium iron manganese phosphate compound (LiFe _1-u Mn _u PO ₄ (u <1)) etc. are mentioned, for example. Can be.

In addition, examples of the positive electrode material capable of occluding and releasing lithium include oxides such as titanium oxide, vanadium oxide or manganese dioxide, disulfides such as titanium sulfide and molybdenum sulfide, and niobium selenide. Or a conductive polymer such as chalcogenide, sulfur, polyaniline or polythiophene.

Of course, the positive electrode material which can occlude and discharge | release lithium may be other than the above. Moreover, 2 or more types of said series of positive electrode materials may be mixed by arbitrary combinations.

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

As a positive electrode electrically conductive agent, carbon materials, such as graphite, carbon black, acetylene black, or Ketjen black, are mentioned, for example. These may be individual or multiple types may be mixed. The positive electrode conductive agent may be a metal material or a conductive polymer, as long as it is a material having conductivity.

The negative electrode 22 has the same structure as the above-mentioned negative electrode, and the negative electrode active material layer 22B is provided on both surfaces of the negative electrode current collector 22A having a pair of faces, for example. Negative electrode current collector 22A The structure of the preliminary negative electrode active material layer 22B is the same as that of the structure of the negative electrode collector 1 and the negative electrode active material layer 2 in said negative electrode, respectively. In this negative electrode 22, the chargeable capacity of the negative electrode material capable of occluding and releasing lithium is preferably larger than the discharge capacity of the positive electrode 21.

The separator 23 isolates the positive electrode 21 and the negative electrode 22 and allows ions of the electrode reactant to pass through while preventing a short circuit of current caused by contact between the positive electrode and the negative electrode 21. The separator 23 is composed of, for example, a porous membrane made of synthetic resin such as polytetrafluoroethylene, polypropylene or polyethylene, a porous membrane made of ceramic, or the like, in which two or more of these porous membranes are laminated. It may be.

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

A solvent contains 1 type, or 2 or more types of non-aqueous solvents, such as an organic solvent, for example. The series of solvents described below may be arbitrarily combined.

As the nonaqueous solvent, for example, ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, methylpropyl carbonate, γ-butyrolactone, γ-valerolactone, 1,2-dime Methoxyethane, 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 Trimethyl Acetate, Ethyl Trimethyl Acetate, Acetonitrile, Glutaronitrile, Adiponitrile, Methoxyacetonitrile, 3-methoxypropio Nitrile, N, N-dimethylformamide, N-methylpyrrolidinone, N-methyloxazolidinone, N, N'-dimethylimidazolidinone, nitromethane, nitroethane, sulfolane, trimethyl phosphate, or dimethyl sulfoxide Seed etc. are mentioned. Especially, at least 1 sort (s) of the group which consists of ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, and ethyl methyl carbonate is preferable. In this case, a high viscosity (high dielectric constant) solvent such as ethylene carbonate or propylene carbonate (e.g. relative permittivity (?) ≥ 30) and a low viscosity solvent such as dimethyl carbonate, ethyl methyl carbonate or diethyl carbonate (e.g. viscosity A combination with ≦ 1 mPa · s) is more preferred. This is because dissociation of electrolyte salts and mobility of ions are improved.

In particular, the solvent preferably contains at least one of a chain carbonate having a halogen represented by the formula (1) as a constituent element and a cyclic carbonate having a halogen represented by the formula (2) as a constituent element. This is because a stable protective film is formed on the surface of the negative electrode 22 during charging and discharging, so that decomposition reaction of the electrolyte solution is suppressed.

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

R11 to R16 in the formula (1) may be the same or different. That is, the types of R11 to R16 can be set individually within the range of the series described above. The same applies to R17 to R20 in the formula (2).

Although the kind of halogen is not specifically limited, Especially, fluorine, chlorine, or bromine is preferable, and fluorine is more preferable. This is because a high effect can be obtained. This is because a high effect can be obtained in comparison with other halogens.

However, the number of halogens is preferably two or more 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 electrolyte solution is more suppressed.

Examples of the linear carbonate ester having a halogen represented by the formula (1) include fluoromethylmethyl carbonate, bis (fluoromethyl) carbonate, difluoromethylmethyl carbonate, and the like. These may be individual or multiple types may be mixed. Especially, bis (fluoromethyl) carbonate is preferable. This is because a high effect can be obtained.

Examples of the cyclic carbonate having a halogen represented by the formula (2) include a series of compounds represented by the formulas (3) and (4). That is, 4-fluoro-1,3-dioxolan-2-one of (1), 4-chloro-1,3-dioxolan-2-one of (2), and (3) 4,5-Difluoro-1,3-dioxolan-2-one, (4) tetrafluoro-1,3-dioxolan-2-one, (5) 4-chloro-5-fluoro -1,3-dioxolan-2-one, 4,5-dichloro-1,3-dioxolan-2-one of (6), tetrachloro-1,3-dioxolan-2-one of (7) , 4,5-bistrifluoromethyl-1,3-dioxolan-2-one of (8), 4-trifluoromethyl-1,3-dioxolan-2-one of (9), (10 4,5-difluoro-4,5-dimethyl-1,3-dioxolan-2-one of), 4,4-difluoro-5-methyl-1,3-dioxolane- of (11)- 2-one, 4-ethyl-5,5-difluoro-1,3-dioxolane-2-one of (12), and the like. In addition, 4-fluoro-5-trifluoromethyl-1,3-dioxolan-2-one of (1) shown in the general formula (4), 4-methyl-5-trifluoro-methyl- of (2) 1,3-dioxolan-2-one, (3) 4-fluoro-4,5-dimethyl-1,3-dioxolan-2-one, (4) 5- (1,1-difluoro Roethyl) -4,4-difluoro-1,3-dioxolan-2-one, 4,5-dichloro-4,5-dimethyl-1,3-dioxolan-2-one of (5), 4-ethyl-5-fluoro-1,3-dioxolan-2-one of (6), 4-ethyl-4,5-difluoro-1,3-dioxolan-2-one of (7) , 4-ethyl-4,5,5-trifluoro-1,3-dioxolan-2-one of (8), 4-fluoro-4-methyl-1,3-dioxolane of (9)- 2-on and the like. These may be individual or multiple types may be mixed.

Among them, 4-fluoro-1,3-dioxolan-2-one or 4,5-difluoro-1,3-dioxolan-2-one is preferred, and 4,5-difluoro-1 , 3-dioxolane-2-one is more preferred. In particular, as 4,5-difluoro-1,3-dioxolan-2-one, a trans isomer is more preferable than a cis isomer. This is because it is easily available and a high effect can be obtained.

In addition, the solvent preferably contains a cyclic carbonate having an unsaturated bond represented by the formulas (5) to (7). It is because the chemical stability of electrolyte solution improves more. These may be individual or multiple types may be mixed.

(R21 and R22 are hydrogen or alkyl group)

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

(R27 is an alkylene group)

The cyclic carbonate having an unsaturated bond represented by the formula (5) is a vinylene carbonate compound. Examples of the vinylene carbonate compound include vinylene carbonate (1,3-dioxol-2-one), methylvinylene carbonate (4-methyl-1,3-dioxol-2-one), and ethyl carbonate. Vinylene (4-ethyl-1,3-dioxol-2-one), 4,5-dimethyl-1,3-dioxol-2-one, 4,5-diethyl-1,3-dioxol- 2-one, 4-fluoro-1,3-dioxol-2-one, or 4-trifluoromethyl-1,3-dioxol-2-one, etc. are mentioned, Especially, vinylene carbonate This is preferred. This is because the service can be obtained and a high effect can be obtained.

The cyclic carbonate having an unsaturated bond represented by the formula (6) is a vinyl ethylene compound. As a vinyl ethylene carbonate type compound, For example, vinyl ethylene carbonate (4-vinyl-1,3-dioxolan-2-one), 4-methyl-4- vinyl-1,3-dioxolan-2-one, 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, or 4,5-divinyl-1,3-dioxolan-2-one, etc. are mentioned, 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-R26, all may be a vinyl group, all may be an allyl group, and a vinyl group and an allyl group may be mixed.

The cyclic carbonate having an unsaturated bond represented by the formula (7) is a methylene ethylene 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, or 4,4-diethyl -5-methylene-1,3-dioxolan-2-one etc. are mentioned. As this methylene ethylene-type compound, what has two methylene groups other than what has one methylene group (compound shown by Formula (7)) may be sufficient.

As the cyclic carbonate having an unsaturated bond, carbonate catechol (catechol carbonate) or the like having a benzene ring may be used, in addition to those shown in the formulas (5) to (7).

Moreover, it is preferable that a solvent contains sultone (cyclic sulfonic acid ester) and an acid anhydride. It is because the chemical stability of electrolyte solution improves more.

Examples of the sultone include propane sultone, furopen sultone, and the like, and among them, furopen sultone is preferable. These may be individual or 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.

Examples of the acid anhydride include, for example, carboxylic anhydrides such as succinic anhydride, glutaric anhydride or maleic anhydride, disulfonic anhydrides such as ethanedisulfonic anhydride or propanedisulfonic anhydride, sulfobenzoic anhydride, sulfopropionic anhydride or sulfo Anhydrides of carboxylic acid and sulfonic acid, such as butyrate anhydride, etc. are mentioned, Especially, a succinic anhydride or a sulfobenzoic anhydride is preferable. These may be unwound independently and multiple types may be mixed. Content of the acid anhydride in a solvent is 0.5 weight% or more and 5 weight% or less, for example.

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

Examples of lithium salts include lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroborate, lithium tetraphenylborate (LiB (C ₆ H ₅ ) ₄ ), and lithium methanesulfonate (LiCH ₃ SO ₃ ). Lithium trifluoromethanesulfonic acid (LiCF ₃ SO ₃ ), lithium tetrachloroaluminate (LiAlCl ₄ ), lithium hexafluorosilicate (Li ₂ SiF ₆ ), lithium chloride (LiCl), or lithium bromide (LiBr); Can be mentioned. This is because excellent electrical performance can be obtained in an electrochemical device.

Especially, at least 1 sort (s) of the group which consists of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, and lithium hexafluorophosphate is preferable, and lithium hexafluorophosphate is more preferable. This is because a higher effect can be obtained because the internal resistance is lowered.

In particular, it is preferable that electrolyte salt contains at least 1 sort (s) of the group which consists of a compound represented by General formula (8)-(10). This is because when used in combination with the lithium hexafluorophosphate or the like, a higher effect can be obtained. In addition, R31 and R33 in Formula (8) may be the same and may differ. This also applies to R41 to R43 in the formula (9) and R51 and R52 in the formula (10).

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

(X41 is a group 1 element or group 2 element in a long periodic table. M41 is a transition metal element or a group 13 element, group 14 element, or group 15 element in a long 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- , provided that R41 and R43 are hydrogen groups, 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, R42 is a hydrogen group, an alkyl group, a halogen group or a halogenated alkyl group, and a4, e4 and n4 are 1 or 2, b4 and d4 is an integer from 1 to 4, c4 is an integer from 0 to 4, f4 and m4 are an integer from 1 to 3)

(X51 is a group 1 element or group 2 element in the long period type table. M51 is a transition metal element or a group 13 element, group 14 element, or group 15 element in the long period type table. Rf is a fluorinated alkyl group. Or a fluorinated aryl group, and any carbon number is 1 to 10. 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 -wherein R51 is a hydrogen group, an alkyl group, a halogen group or a halogenated alkyl group 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 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, g5 and m5 are integers of 1 to 3)

In addition, a long-period type periodic table is represented by the revised edition of the Inorganic Chemistry Nomenclature proposed by the International Union of Pure and Applied Chemistry. Specifically, Group 1 elements are hydrogen, lithium, sodium, potassium, rubidium, cesium, and francium. Group 2 elements are beryllium, magnesium, calcium, strontium, barium and radium. Group 13 elements are boron, aluminum, gallium, indium and thallium. Group 14 elements are carbon, silicon, germanium, tin and lead. Group 15 elements are nitrogen, phosphorus, arsenic, antimony and bismuth.

As a compound represented by General formula (8), the compound etc. which are represented by (1)-(6) of General formula (11) are mentioned, for example. As a compound represented by General formula (9), the compound etc. which are represented by (1)-(8) of General formula (12) are mentioned, for example. As a compound represented by General formula (10), the compound etc. which are represented by General formula (13) are mentioned, for example. In addition, if it is a compound which has a structure shown in Formula (8)-Formula (10), it cannot be overemphasized that it is not limited to the compound shown in Formula (11)-(13).

Moreover, the electrolyte salt may contain at least 1 sort (s) of the crowd which consists of a compound represented by General formula (14)-(16). This is because when used in combination with the lithium hexafluorophosphate or the like, a higher effect can be obtained. In addition, m and n in Formula 14 may be the same and may differ. This also applies to p, q and r in the formula (16).

(m and n are integers of 1 or more)

(R61 is a C2-C4 straight or branched perfluoroalkylene group)

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

Examples of the chain compound shown in the formula (14) include bis (trifluoromethanesulfonyl) imide lithium (LiN (CF ₃ SO ₂ ) ₂ ) and 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) (nonnafluorobutane Sulfonyl) imide lithium (LiN (CF ₃ SO ₂ ) (C ₄ F ₉ SO ₂ )) and the like. These may be individual or multiple types may be mixed.

As a cyclic compound represented by General formula (15), a series of compounds represented by General formula (17) are mentioned, for example. That is, 1,2-perfluoroethane disulfonylimide lithium of (1) shown in General formula (17), 1, 3- perfluoro propane disulfonylimide lithium of (2), and 1,3 of (3) -Perfluorobutane disulfonylimide lithium, the 1, 4- perfluoro butane disulfonylimide lithium of (4), etc .; These may be individual or multiple types may be mixed. Especially, 1, 2- perfluoro ethane disulfonylimide lithium is preferable. This is because a high effect can be obtained.

Examples of the chain compound represented by the formula (16) include lithium tris (trifluoromethanesulfonyl) methide (LiC (CF ₃ SO ₂ ) ₃ ) and the like.

It is preferable that content of electrolyte salt is 0.3 mol / kg or more and 3.0 mol / kg or less with respect to a solvent. It is because there exists a possibility that ion conductivity may fall extremely outside this range.

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

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

Next, the negative electrode active material layer 22B is formed on both surfaces of the negative electrode current collector 22A by the same procedure as that for producing the negative electrode, thereby producing the negative electrode 22.

Next, the battery element 20 is manufactured using the positive electrode 21 and the negative electrode 22. First, the positive electrode lead 24 is attached to the positive electrode current collector 21A by welding or the like, and the negative electrode lead 25 is attached to the negative electrode current collector 22A by welding or the like. Subsequently, the positive electrode 21 and the negative electrode 22 are laminated through the separator 23, and then wound in the long side direction. Finally, the wound body is molded to have a flat shape.

The secondary battery is assembled as follows. First, after storing the battery element 20 inside the battery can 11, the insulating plate 12 is arranged on the battery element 20. Subsequently, the positive electrode lead 24 is connected to the positive electrode pin 15 by welding or the like, and the negative electrode lead 25 is connected to the battery can 11 by welding or the like, and then the battery can is formed by laser welding or the like. The battery cover 13 is fixed to the open end of (11). Finally, the electrolyte is injected into the battery can 11 from the injection hole 19 and impregnated in the separator 23, and then the injection hole 19 is closed with a sealing member 19A. Thereby, the secondary battery shown in FIG. 5 and FIG. 6 is completed.

In this secondary battery, when charged, for example, lithium ions are released from the positive electrode 21 and occluded in the negative electrode 22 through the electrolyte solution impregnated with the separator 23. On the other hand, when discharged, lithium ions are released from the negative electrode 22, for example, and stored in the positive electrode 21 through the electrolyte solution impregnated with the separator 23.

According to this rectangular secondary battery, since the negative electrode 22 has the same structure as the negative electrode described above, the cycle characteristics and the first charge / discharge characteristics can be improved.

In particular, the solvent of the electrolyte solution is at least one of the chain carbonate ester having a halogen represented by the formula (1) and the cyclic carbonate ester having a halogen represented by the formula (2), or the ring having an unsaturated bond represented by the formulas (5) to (7). If it contains at least 1 sort (s) of carbonate ester, sultone, and an acid anhydride, a higher effect can be acquired.

Moreover, the electrolyte salt of electrolyte salt is at least 1 sort (s) of the crowd which consists of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, and lithium hexafluoro fluoride, or at least 1 sort (s) of crowd consisting of the compound shown by Formula (8)-(10). However, higher effect can be obtained if it contains at least 1 sort (s) of the crowd which consists of a compound shown by General formula (14)-(16).

If the battery can 11 is made of hard metal, the negative electrode 22 is less likely to be damaged when the negative electrode active material layer 22B expands and contracts as compared with the case of the soft film. Therefore, cycling characteristics can be improved more. In this case, if the battery can 11 is made of iron harder than aluminum, a higher effect can be obtained.

Effects other than the above regarding this secondary battery are the same as the above-mentioned negative electrode.

(Second secondary battery)

7 and 8 show the cross-sectional structure of the second secondary battery, and in FIG. 8, a part of the wound electrode body 40 shown in FIG. 7 is enlarged. The second secondary battery is a lithium ion secondary battery, for example, similarly to the above-described first secondary battery. This second secondary battery is mainly a wound electrode body 40 in which a positive electrode 41 and a negative electrode 42 are laminated and wound in a substantially hollow cylindrical battery cell 31 through a separator 43. ) And a pair of insulating plates 32 and 33 are housed. The battery structure including this battery can 31 is called a cylindrical shape.

The battery can 31 is made of, for example, the same metal material as the battery can 11 in the first secondary battery, and one end and the other end thereof are closed and open, respectively. The pair of insulating plates 32 and 33 sandwich the wound electrode body 40 from above and below, and are disposed so as to extend vertically with respect to the wound main surface.

At the open end of the battery can 31, a battery cover 34, a safety valve mechanism 35 and a thermal resistance element (Positive Temperature Coefficient: PTC element) 36 provided therein are provided through the gasket 37. It is attached by caulking. As a result, the inside of the battery can 31 is sealed. The battery cover 34 is made of, for example, a metal material such as the battery can 31. The safety valve mechanism 35 is electrically connected to the battery cover 34 via the thermal resistance element 36. In this safety valve mechanism 35, when the internal pressure becomes constant due to an internal short circuit, heating from the outside, or the like, the disk plate 35A is inverted and the battery cover 34 and the wound electrode body 40 are separated. The electrical connection of the is cut off. The thermal resistance element 36 limits the current by increasing the resistance in response to the rise in temperature, and prevents abnormal heat generation caused by the large current. The gasket 37 is made of, for example, an insulating material, and asphalt is coated on the surface thereof.

The center pin 44 may be inserted in the center of the wound electrode body 40. In the wound electrode body 40, the positive electrode lead 45 made of a metal material such as aluminum is connected to the positive electrode 41, and the negative electrode lead 46 made of a metal material such as nickel is used as the negative electrode ( 42). The positive electrode lead 45 is welded to the safety valve mechanism 35 to be electrically connected to the battery cover 34, and the negative electrode lead 46 is welded to the battery can 31 to be electrically connected. It is.

For example, the positive electrode active material layer 41B is provided on both surfaces of a positive electrode current collector 41A having a pair of faces. The negative electrode 42 has the same structure as the above-mentioned negative electrode, and the negative electrode active material layer 42B is provided on both surfaces of the negative electrode current collector 42A having a pair of surfaces, for example. The composition of the positive electrode current collector 41A, the positive electrode active material layer 41B, the negative electrode current collector 42A, the negative electrode active material layer 42B, and the separator 43, and the composition of the electrolyte solution, respectively, are the first secondary battery described above. It is similar to the structure of the positive electrode current collector 21A, the positive electrode active material layer 21B, the negative electrode current collector 22A, the negative electrode active material layer 22B and the separator 23, and the composition of the electrolyte solution.

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

First, for example, the positive electrode active material layer 41B is placed on both surfaces of the positive electrode current collector 41A in the same procedure as the manufacturing procedures of the positive electrode 21 and the negative electrode 22 in the first secondary battery. While forming the positive electrode 41, the negative electrode active material layer 42B is formed on both surfaces of the negative electrode current collector 42A to form the negative electrode 42. Subsequently, the positive electrode lead 45 is attached to the positive electrode 41 by welding or the like, and the negative electrode lead 46 is attached to the negative electrode 42 by welding or the like. Then, the positive electrode 41 and the negative electrode 42 are laminated | stacked and wound up through the separator 43, the wound electrode body 40 is produced, and the center pin 44 is inserted in the winding center. Subsequently, the wound electrode body 40 is accommodated inside the battery can 31 while being sandwiched by the pair of insulating plates 32 and 33, and the tip of the positive electrode lead 45 is welded to the safety valve mechanism 35. The tip end of the negative electrode lead 46 is welded to the battery can 31. Subsequently, an electrolyte is injected into the battery can 31 and impregnated in the separator 43. Finally, the battery cover 34, the safety valve mechanism 35, and the thermal resistance element 36 are cocked and fixed to the opening end of the battery can 31 through the gasket 37. Thereby, the secondary battery shown in FIG. 7 and FIG. 8 is completed.

In this secondary battery, when charged, for example, lithium ions are released from the positive electrode 41 and occluded in the negative electrode 42 through the electrolyte solution. On the other hand, when discharging, lithium ions are released from the negative electrode 42, for example, and stored in the positive electrode 41 through the electrolyte solution.

According to this cylindrical secondary battery, since the negative electrode 42 has the same structure as the above-described negative electrode, the cycle characteristics and the first charge / discharge characteristics can be improved. Effects other than the above concerning this secondary battery are the same as that of a 1st secondary battery.

(Third secondary battery)

FIG. 9 shows an exploded perspective configuration of the third secondary battery, and FIG. 10 shows an enlarged cross section along the X-X line shown in FIG. 9. The third secondary battery is a lithium ion secondary battery, for example, similarly to the above-described first secondary battery. In this third secondary battery, the wound electrode body 50 having the positive electrode lead 51 and the negative electrode lead 52 is mainly housed inside the film-shaped exterior member 60. The battery structure including this exterior member 60 is called a laminate film type.

The positive electrode lead 51 and the negative electrode lead 52 are led in the same direction from the inside of the exterior member 60 to the outside, for example. The positive electrode lead 51 is made of, for example, a metal material such as aluminum, and the negative electrode lead 52 is made of, for example, a metal material such as copper, nickel, or stainless steel. These metal materials have a thin plate shape or a mesh shape, for example.

The exterior member 60 is comprised by the aluminum laminate film by which nylon film, aluminum foil, and a polyethylene film matched in this order, for example. The exterior member 60 has, for example, a structure in which the 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 50. have.

The adhesion film 61 is inserted between the exterior member 60, the positive electrode lead 51, and the negative electrode lead 52 in order to prevent invasion of external air. This adhesion film 61 is comprised with the material which has adhesiveness with respect to the positive electrode lead 51 and the negative electrode lead 52. As such a material, polyolefin resin, such as polyethylene, a polypropylene, modified polyethylene, or a modified polypropylene, is mentioned, for example.

In addition, the exterior member 60 may be comprised by the laminated film which has another laminated structure instead of said aluminum laminate film, and may be comprised by the high polymer film or metal film, such as polypropylene.

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

The positive electrode 53 is provided with, for example, the positive electrode active material layer 53B on both surfaces of a positive electrode current collector 53A having a pair of faces. The negative electrode 54 has the same structure as the above-described negative electrode, and the negative electrode active material layer 54B is provided on both surfaces of the negative electrode current collector 54A having a pair of surfaces, for example. The configurations of the positive electrode current collector 53A, the positive electrode active material layer 53B, the negative electrode current collector 54A, the negative electrode active material layer 54B, and the separator 55 are each a positive electrode current collector in the first secondary battery described above. It is the same as the structure of 21A, the positive electrode active material layer 21B, the negative electrode collector 22A, the negative electrode active material layer 22B, and the separator 23. As shown in FIG.

The electrolyte 56 contains an electrolyte solution and a high molecular compound that supports it, and is a so-called gel electrolyte. The gel electrolyte is preferable because high ionic conductivity (for example, 1 mS / cm or more at room temperature) can be obtained and leakage is prevented.

Examples of the high molecular compound include polyacrylonitrile, polyvinylidene fluoride, copolymers of polyvinylidene fluoride and polyhexafluoropyrene, polytetrafluoroethylene, polyhexafluoropropylene, polyethylene oxide, and polypropylene. Oxides, polyphosphazenes, polysiloxanes, polyvinyl acetate, polyvinyl alcohol, polymethyl methacrylate, polyacrylic acid, polymethacrylic acid, styrene-butadiene rubber, nitrile-butadiene rubber, polystyrene, polycarbonate, and the like. . These may be individual or multiple types may be mixed. Especially, polyacrylonitrile, polyvinylidene fluoride, polyhexafluoropropylene, or polyethylene oxide is preferable. This is because it is electrochemically stable.

The composition of electrolyte solution is the same as that of the electrolyte solution in a 1st secondary battery. However, in the electrolyte 56 that is a gel electrolyte, the solvent of the electrolyte solution is a broad concept that includes not only a liquid solvent but also an ion conductivity capable of dissociating an electrolyte salt. Therefore, when using the high molecular compound which has ion conductivity, the high molecular compound is also contained in a solvent.

In addition, you may use the electrolyte solution as it is instead of the gel electrolyte 56 which preserve | saved the electrolyte solution in the high molecular compound. In this case, the electrolyte solution is impregnated into the separator 55.

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

In the first manufacturing method, both surfaces of the positive electrode current collector 53A are first manufactured by the same procedure as that of manufacturing the positive electrode 21 and the negative electrode 22 in the first secondary battery described above. The positive electrode active material layer 53B is formed on the positive electrode 53, and the negative electrode active material layer 54B is formed on both surfaces of the negative electrode current collector 54A to produce the negative electrode 54. Subsequently, a precursor solution containing an electrolyte solution, a high molecular compound, and a solvent is prepared and applied to the positive electrode 53 and the negative electrode 54, and then the solvent is volatilized to form a gel electrolyte 56. Subsequently, the positive electrode lead 51 is attached to the positive electrode current collector 53A, and the negative electrode lead 52 is attached to the negative electrode current collector 54A. Subsequently, the positive electrode 53 and the negative electrode 54 on which the electrolyte 56 is formed are laminated and wound through the separator 55, and then the protective tape 57 is adhered to the outermost circumference of the wound electrode body 50. To make. Finally, for example, after the wound electrode body 50 is sandwiched between two film-like exterior members 60, the outer edges of the exterior member 60 are bonded to each other by thermal fusion or the like to wound the electrode. The sieve 50 is enclosed. At this time, the adhesion film 61 is inserted between the positive electrode lead 51 and the negative electrode lead 52 and the exterior member 60. Thereby, the secondary battery shown in FIG. 9 and FIG. 10 is completed.

In the second manufacturing method, first, the positive electrode lead 51 is attached to the positive electrode 53, and the negative electrode lead 52 is attached to the negative electrode 54. Subsequently, the positive electrode 53 and the negative electrode 54 are laminated and wound through the separator 55, and then the protective tape 57 is adhered to the outermost circumference thereof, and the wound body which is a precursor of the wound electrode body 50 is wound. To produce. Subsequently, after the wound body is sandwiched between the two film-like exterior members 60, the outer peripheral edges other than the one side peripheral edge portion are bonded by heat fusion, and the inside of the bag-shaped exterior member 60 The wound body is stored in. Subsequently, an electrolyte composition containing an electrolyte solution, a monomer which is a raw material of a high molecular compound, a polymerization initiator, and other materials such as a polymerization inhibitor, if necessary, was prepared and injected into the bag-shaped exterior member 60. Thereafter, the opening of the exterior member 60 is sealed by heat fusion or the like. Finally, the polymer electrolyte is thermally polymerized to form a high molecular compound, thereby forming a gel electrolyte 56. This completes the secondary battery.

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 55 coated on both surfaces is firstly used in the third manufacturing method. It is housed in the inside. As a high molecular compound apply | coated to this separator 55, the polymer which has vinylidene fluoride as a component, ie, a homopolymer, a copolymer, or a polymembered copolymer, etc. are mentioned, for example. Specifically, polyvinylidene fluoride, binary copolymers containing vinylidene fluoride and hexafluoropropylene, or terpolymers containing vinylidene fluoride, hexafluoropropylene and chlorotrifluoroethylene as components. And so on. In addition, the high molecular compound may contain another 1 type, or 2 or more types of high molecular compounds with the polymer which uses said vinylidene fluoride as a component. Subsequently, after preparing an electrolyte solution and inject | pouring into the exterior member 60, the opening part of the exterior member 60 is sealed by heat sealing etc. Finally, it heats, applying the weight to the exterior member 60, and the separator 55 adheres to the positive electrode 53 and the negative electrode 54 through a high molecular compound. As a result, the electrolyte solution is impregnated with the high molecular compound, and the high molecular compound is gelled to form the electrolyte 56, thereby completing the secondary battery.

In this third manufacturing method, expansion of the secondary battery is suppressed as compared with the first manufacturing method. In addition, in the third manufacturing method, since the monomer, the solvent, and the like which are the raw materials of the high molecular compound are hardly left in the electrolyte 56 compared with the second manufacturing method, the formation process of the high molecular compound is controlled well. Sufficient adhesiveness can be obtained between the positive electrode 53, the negative electrode 54, and the separator 55 and the electrolyte 56.

According to this laminated film type secondary battery, since the negative electrode 54 has the same structure as the above-described negative electrode, the cycle characteristics and the first charge / discharge characteristics can be improved. Effects other than the above concerning this secondary battery are the same as that of a 1st secondary battery.

EXAMPLE

Embodiments of the present invention will be described in detail.

(Example 1-1)

The laminated film secondary battery shown in FIG. 9 and FIG. 10 was manufactured by the following procedure. At this time, the capacity of the negative electrode 54 was such that the lithium ion secondary battery displayed based on the occlusion and release of lithium.

Initially, the positive electrode 53 was produced. First, lithium carbonate (Li ₂ CO ₃ ) and cobalt carbonate (CoCO ₃ ) were mixed in a molar ratio of 0.5: 1, and then calcined at 900 ° C. in air for 5 hours to obtain a lithium cobalt composite oxide (LiCoO ₂ ). . Subsequently, after mixing 91 mass parts of lithium cobalt composite oxides as a positive electrode active material, 6 mass parts of graphite as a positive electrode electrically conductive agent, and 3 mass parts of polyvinylidene fluoride as a positive electrode binder, it is N-methyl-2-. It disperse | distributed to pyrrolidone and it was set as the paste-form positive mix slurry. Finally, the positive electrode mixture slurry is uniformly applied to both surfaces of the positive electrode current collector 53A made of a strip-shaped aluminum foil (thickness = 12 μm), dried, and then compressed by a roll press to form a positive electrode active material layer 53B. ) Was formed.

Next, the negative electrode 54 was produced. First, an electrolytic copper foil roughened as the negative electrode current collector 54A (thickness = 18 µm, 10-point average roughness (Rz) = 10 µm), and silicon powder (median diameter = 30 µm) were prepared as the negative electrode active material. Thereafter, silicon powder was sprayed onto both surfaces of the negative electrode current collector 54A in a molten state by the spray method to form a plurality of negative electrode active material particles, thereby forming the negative electrode active material layer 54B. In this spraying method, the spraying process was performed while using a gas flame spray, the spraying speed was about 45 m / sec to 55 m / sec, and the base was cooled with carbon dioxide so that the negative electrode current collector 54A would not bear thermal damage. . In the case of forming the negative electrode active material layer 54B, the oxygen content in the negative electrode active material was 5 atomic% by introducing oxygen gas into the chamber. In addition, the plurality of negative electrode active material particles contain flat particles (flat particles: oily), and the negative electrode active material layer 54B does not include a portion that does not contact the negative electrode current collector 54A (non-contact portion: non-contact). ), The negative electrode active material layer 54B has a void therein (void: oil). At this time, by adjusting the melting temperature of the silicon powder and the cooling temperature of the base, the half width (2θ) of the diffraction peak in the (111) crystal plane of the negative electrode active material obtained by X-ray diffraction is set to 20 °, and the copper crystal plane The crystallite size attributable to was 10 nm. In addition, when performing said X-ray-diffraction analysis, the X-ray diffraction apparatus by Rigaku Electric Machinery Co., Ltd. was used. At this time, CuKa was used as the tube, and the tube voltage was 40 mA, the tube current was 40 mA, and the scanning method was the θ-2θ method and the measurement range was 20 ° ≦ 2θ ≦ 90 °.

Next, after mixing ethylene carbonate (EC) and diethyl carbonate (DEC) as a solvent, lithium hexafluorophosphate (LiPF ₆ ) was dissolved as an electrolyte salt, and the electrolyte solution was prepared. At this time, the composition (EC: DEC) of the solvent was 50:50 in weight ratio, and the content of the electrolyte salt was 1 mol / kg with respect to the solvent.

Finally, the secondary battery was assembled using the electrolyte solution together with the positive electrode 53 and the negative electrode 54. Initially, the aluminum positive electrode lead 51 was welded to one end of the positive electrode current collector 53A, and the negative electrode lead 52 made of nickel was welded to one end of the negative electrode current collector 54A. Subsequently, the separator 55 (thickness = 23 μm) having a positive electrode 53, a film containing porous polypropylene as a main component, and a film composed of porous polyethylene as a main component, a negative electrode 54, After laminating the above-mentioned separator 55 in this order and winding it in the long side direction, the end wound by the protective tape 57 which consists of an adhesive tape is fixed, and the winding body which is a precursor of the wound electrode body 50 is formed. It was. Subsequently, the laminated film (total thickness = 100) of which the nylon film (thickness = 30 micrometer), aluminum foil (thickness = 40 micrometer), and an unstretched polypropylene film (thickness = 30 micrometer) laminated | stacked from the outer side After the wound body was sandwiched between the exterior members 60 made of micrometers), the outer edge portions except for one side were thermally fused to accommodate the wound body inside the bag-shaped exterior member 60. Then, electrolyte solution was injected from the opening part of the exterior member 60, and it impregnated into the separator 55, and the wound electrode body 50 was produced. Finally, the laminated film type secondary battery was completed by heat-sealing and sealing the opening part of the exterior member 60 in a vacuum atmosphere. In addition, when manufacturing a secondary battery, lithium metal was not deposited in the negative electrode 54 at the time of full charge by adjusting the thickness of the positive electrode active material layer 53B.

About this secondary battery, the cycling characteristics and initial charge / discharge characteristic mentioned later were investigated within 1 week after manufacture.

(Examples 1-2 to 1-10)

The half width and the crystallite size were 12 ° and 15 nm (Example 1-2), 5 ° preliminary 20 nm (Example 1-3), 3 ° and 30 nm (Example 1-4), 2 ° and 50, respectively. Nm (Examples 1-5), 1 ° and 70 nm (Examples 1-6), 0.9 ° and 100 nm (Examples 1-7), 0.8 ° and 120 nm (Examples 1-8), 0.7 ° And 135 nm (Example 1-9) or 0.6 ° and 150 nm (Example 1-10), except that the procedure was the same as in Example 1-1.

(Examples 1-11, 1-12)

After the manufacture of the secondary battery, the cycle characteristics and the first charge and discharge characteristics were examined at the time point two weeks after (Example 1-11) or one month after the time (Example 1-12), except that In the same order.

(Comparative Examples 1-1 to 1-5)

The half width and the crystallite size were 30 ° and 1 nm (Comparative Example 1-1), 27 ° and 2 nm (Comparative Example 1-2), 25 ° and 5 nm (Comparative Example 1-3), 23 ° and 7, respectively. The same procedure as in Example 1-1 was performed except that the thickness was changed to nm (Comparative Example 1-4) or 21 ° and 9 nm (Comparative Example 1-5).

(Comparative Examples 1-6, 1-7)

After the manufacture of the secondary battery, the cycle characteristics and the first charge / discharge characteristics were examined at the time point two weeks passed (Comparative Example 1-6) or one month later (Comparative Example 1-7), and Comparative Example 1-1 and In the same order.

The cycle characteristics, the first charge-discharge characteristics, and their changes over time were examined for the secondary batteries of Examples 1-1 to 1-12 and Comparative Examples 1-1 to 1-7, and Table 1, Table 2, and FIG. And the results shown in FIG. 12 were obtained.

When examining the cycle characteristics, a cycle test was conducted to determine the discharge capacity retention rate. Specifically, first, after charging and discharging in an atmosphere at 23 ° C. in order to stabilize the battery state, the battery was charged and discharged again, and the discharge capacity at the second cycle was measured. Subsequently, 99 cycles were charged and discharged in the same atmosphere, and the discharge capacity at the 101st cycle was measured. Finally, discharge capacity retention rate (%) = (discharge capacity at 101 cycle // 2 cycle capacity) x 100 was calculated. At this time, as the charging conditions, the battery was charged at a constant current density of 3 mA / cm 2 until the battery voltage reached 4.2 V, and then charged at a constant voltage of 4.2 V until the current density reached 0.3 mA / cm 2. . Moreover, as discharge conditions, it discharged until the battery voltage reached 2.5V at the constant current density of 3 mA / cm <2>.

When the first charge / discharge characteristic was investigated, initially, after charging and discharging in an atmosphere of 23 ° C. in order to stabilize the battery state, the battery was charged again and the charging capacity was measured. Then, it discharged in the same atmosphere and measured discharge capacity. Finally, initial charge / discharge efficiency (%) = (discharge capacity / charge capacity) x 100 was calculated. The charging and discharging conditions were the same as in the case of examining the cycle characteristics.

In addition, the procedure and conditions at the time of investigating cycling characteristics and a first charge / discharge characteristic are the same also about evaluation of the same characteristic about a following series of Examples and a comparative example.

As shown in Table 1, Table 2, Fig. 11, and Fig. 12, as the half-value width decreases and the crystallite size increases, the discharge capacity retention rate and the initial charge-discharge efficiency both increase and decrease. In this case, in Examples 1-1 to 1-10 in which the crystallite size is 10 nm or more while the half value width is 20 ° or less, the crystal state of the negative electrode active material becomes crystalline, and the half value width is more than 20 ° and the crystallites In Comparative Examples 1-1 to 1-5 having a size of less than 10 nm, the crystal state of the negative electrode active material became amorphous (amorphous).

Here, attention was paid to the influence of the crystalline state (half-value width and crystallite size) of the negative electrode active material on the discharge capacity retention rate and the initial charge / discharge efficiency. In Examples 1-1 to 1-10, which are crystalline, Comparative Example 1- is amorphous. Compared with 1 to 1-5, a high discharge capacity retention rate and first charge and discharge efficiency of 80% or more were obtained. In particular, in Examples 1-1 to 1-10, when the half-value width was 5 degrees or less and the crystallite size was 20 nm or more, the discharge capacity retention rate and initial charge / discharge efficiency which were markedly high by 90% or more were obtained. In this case, if the crystallite size is 20 nm or more and 100 nm or less while the half width is 0.9 ° or more and 5 ° or less, the crystallite size does not become too large. Lowered.

In addition, attention was paid to the change in the discharge capacity retention rate and the initial charge / discharge efficiency over time. In Comparative Examples 1-1, 1-6, and 1-7, which are amorphous, both the discharge capacity retention rate and the first charge / discharge efficiency were changed with time. Although lowered, in Example 1-6, 1-11, and 1-12 which are crystalline, even if time passed, discharge capacity retention rate and initial charge / discharge efficiency were constant.

These results indicate that when the negative electrode active material has crystallinity, since the negative electrode active material layer 54B becomes difficult to expand and contract during charge and discharge, the discharge capacity retention rate and the first charge and discharge efficiency are high. In addition, since the physical properties of the negative electrode active material having crystallinity are unlikely to change over time, the discharge capacity retention rate and the first charge-discharge efficiency are also less likely to deteriorate with time.

From these, in the secondary battery of this invention, by forming the negative electrode active material layer 54B containing the crystalline negative electrode active material which has silicon as a structural element using the spray method so that it may be connected to the negative electrode collector 54A, It was confirmed that the cycle characteristics and the first charge / discharge characteristics were improved, and their deterioration with time was suppressed. In this case, the half-value width (2θ) of the diffraction peak on the (111) crystal plane of the negative electrode active material obtained by X-ray diffraction is 20 ° or less, and the crystallite size is 10 nm or more, preferably 0.9 ° or more and 5 ° It was also confirmed that the crystallinity of the negative electrode active material was ensured as it was 20 nm or more and 100 nm or less, and both characteristics were further improved while preventing damage to the negative electrode active material layer 54B.

(Comparative Examples 2-1 to 2-4)

A negative electrode active material layer was formed by vapor deposition (deflection electron beam vapor deposition), and the half width and the crystal eye size were 30 ° and 1 nm (Comparative Example 2-1), 27 ° and 2 nm (Comparative Example 2-2, respectively). ), 25 ° and 4 nm (Comparative Example 2-3), or 21 ° and 8 nm (Comparative Example 2-4), except that the procedure was the same as in Example 1-1. At this time, silicon having a purity of 99% was used as the deposition source, the deposition rate was 100 nm / sec, and the thickness of the negative electrode active material layer was 12 μm.

(Comparative Examples 2-5, 2-6)

A negative electrode active material layer was formed using sputtering method (RF magnetron sputtering method), and the half value width and crystallite size were 26 ° and 3 nm (Comparative Example 2-5), or 22 ° and 9 nm (Comparative Example 2-6). The same procedure as in Example 1-1 was carried out except for changing to). At this time, using a silicon having a purity of 99.99% as a target, the deposition rate was 0.5 nm / second, and the thickness of the negative electrode active material layer was 12 μm.

(Comparative Examples 2-7, 2-8)

The negative electrode active material layer was formed by CVD and the half width and crystallite size were changed to 25 ° and 5 nm (Comparative Example 2-7), or 21 ° and 9 nm (Comparative Example 2-8), respectively. The same procedure as in Example 1-1 was carried out. At this time, silane (SiH ₄ ) and argon (Ar) were used as raw materials and excitation gases, respectively, the deposition rate was 1.5 nm / second, the substrate temperature was 200 ° C., and the thickness of the negative electrode active material layer was It was set to 11 micrometers.

The cycle characteristics and the first charge / discharge characteristics of the secondary batteries of Comparative Examples 2-1 to 2-8 were examined, and the results shown in Table 3 were obtained.

As shown in Table 3, in Comparative Examples 2-1 to 2-8 using the evaporation method and the like, unlike in Examples 1-1 to 1-4 using the spray method, the crystal state of the negative electrode active material became amorphous. For this reason, as in the result of Table 1, in Examples 1-1 to 1-4 in which the crystal state of the negative electrode active material is crystalline, compared with amorphous Comparative Examples 2-1 to 2-8, a high discharge capacity retention rate and first time Charge and discharge efficiency was obtained. As a result, when the vapor deposition method or the like is used as the method for forming the negative electrode active material layer 54B, since the crystal state of the negative electrode active material does not become crystalline, sufficient discharge capacity retention rate and initial charge / discharge efficiency cannot be obtained. It is shown.

From these, it was confirmed that in the secondary battery of the present invention, by using the spray method as the method for forming the negative electrode active material layer 54B, the cycle characteristics and the first charge / discharge characteristics were improved compared with the case of using the vapor deposition method or the like.

(Examples 2-1 to 2-3)

The same procedure as in Examples 1-5 to 1-7 was followed except that the plurality of negative electrode active material particles did not contain flat particles.

The cycle characteristics and the first charge / discharge characteristics of the secondary batteries of Examples 2-1 to 2-3 were examined, and the results shown in Table 4 were obtained.

As shown in Table 4, even when a plurality of negative electrode active material particles did not contain flat particles, the same results as in Table 1 were obtained. That is, in Examples 2-1 to 2-3 in which the crystal state of the negative electrode active material is crystalline, as in Examples 1-5 to 1-7, 80% or more higher than in Comparative Examples 1-1 to 1-5 The discharge capacity retention rate and the first charge / discharge efficiency were obtained.

In particular, in the case where the crystal state of the negative electrode active material is crystalline, in Examples 1-5 to 1-7 containing flat particles, the discharge capacity retention rate is compared with Examples 2-1 to 2-3 containing no flat particles. And first charge and discharge efficiency was increased.

From these, in the secondary battery of this invention, it was confirmed that cycling characteristics and initial charge / discharge characteristics improve with or without flat particles. In this case, it was also confirmed that when the flat particles were included, both characteristics were further improved.

(Example 3)

The same procedure as in Example 1-6 was performed except that the negative electrode active material layer 54B included the non-contact portion.

The cycle characteristics and the first charge / discharge characteristics of the secondary battery of Example 3 were examined, and the results shown in Table 5 were obtained.

Moreover, about the secondary batteries of Examples 1-6 and 3, the state change of the negative electrode electrical power collector after a cycle test was also investigated. In this case, the secondary battery after the cycle test was disassembled, and it was visually observed whether or not deformation such as wrinkles occurred in the negative electrode current collector 54A.

As shown in Table 5, even when the negative electrode active material layer 54B contained a non-contact portion, the same results as in Table 1 were obtained. That is, in Example 3 in which the crystal state of the negative electrode active material is crystalline, as in Example 1-6, a high discharge capacity retention rate and initial charge / discharge efficiency of 80% or more are obtained in comparison with Comparative Examples 1-1 to 1-5. lost.

In particular, when the crystal state of the negative electrode active material is crystalline, the discharge capacity retention rate and the first charge / discharge efficiency were higher in Example 1-6, which did not include the non-contact portion, compared with Example 3 including the same. In this case, in Example 3 including the non-contact portion, no deformation of the negative electrode current collector 54A was observed, but in Example 1-6, which did not include the non-contact portion, the negative electrode current collector having a small allowable degree ( A variation of 54A) was observed.

From these, it was confirmed that in the secondary battery of the present invention, the cycle characteristics and the first charge / discharge characteristics were improved regardless of the presence or absence of the non-contact portion. In this case, it was also confirmed that when the non-contact portion was not included, both characteristics were further improved, and when the non-contact portion was included, deformation of the negative electrode current collector 54A was suppressed.

(Example 4)

The same procedure as in Example 1-6 was performed except that the negative electrode active material layer 54B did not have voids.

The cycle characteristics and the first charge / discharge characteristics of the secondary battery of Example 4 were examined, and the results shown in Table 6 were obtained.

In addition, the expansion characteristics of the secondary batteries of Examples 1-6 and 4 were also examined. Specifically, initially, after charging and discharging in an atmosphere of 23 ° C. in order to stabilize the battery state, the thickness before the cyclization test was measured. Subsequently, after performing the said cycle test, the thickness after a cycle test was measured. Finally, expansion ratio (%) = [(thickness after cycle test-thickness before cycle test) / thickness before cycle test] × 100 was calculated.

As shown in Table 6, even when the negative electrode active material layer 54B did not have a space | gap, the result similar to Table 1 was obtained. That is, in Example 4 in which the crystal state of the negative electrode active material was crystalline, as in Example 1-6, a high discharge capacity retention ratio and initial charge / discharge efficiency of 80% or more were compared with Comparative Examples 1-1 to 1-5. Obtained.

In particular, in the case where the crystal state of the negative electrode active material is crystalline, in Example 1-6 having voids, the discharge capacity retention ratio was higher and the expansion ratio was also smaller than that of Example 4 having no void.

From these, it was confirmed that in the secondary battery of the present invention, the cycle characteristics and the first charge / discharge characteristics were improved regardless of the presence or absence of voids. In this case, when it has a space | gap, it was also confirmed that while improving a characteristic, an expansion characteristic also improves.

(Examples 5-1 to 5-9)

The oxygen content in the negative electrode active material is 0.5 atomic% (Example 5-1), 1 atomic% (Example 5-2), 1.5 atomic% (Example 5-3), and 2 atomic% (Example 5-4), 10 atomic% (Example 5-5), 20 atomic% (Example 5-6), 30 atomic% (Example 5-7), 40 atomic% (Example 5- 8) or the same procedure as in Example 1-6 except for changing to 45 atomic% (Example 5-9). At this time, the oxygen content was changed by adjusting the amount of the oxygen gas introduced into the chamber.

The cycle characteristics and the first charge / discharge characteristics of the secondary batteries of Examples 5-1 to 5-9 were examined, and the results shown in Table 7 and FIG. 13 were obtained.

As shown in Table 7 and FIG. 13, even when the oxygen content in the negative electrode active material was changed, the same results as in Table 1 were obtained. That is, in Examples 5-1 to 5-9 in which the crystal state of the negative electrode active material is crystalline, as in Example 1-6, compared with Comparative Examples 1-1 to 1-5, a high discharge capacity retention rate of 80% or more and First charge / discharge efficiency was obtained.

In particular, in Examples 1-6 and 5-1 to 5-9 in which the crystal state of the negative electrode active material is crystalline, as the oxygen content increases, the discharge capacity retention rate increases and the initial charge and discharge efficiency tends to decrease. It was. In this case, when oxygen content was 1.5 atomic% or more and 40 atomic% or less, the discharge capacity retention rate and the first charge / discharge efficiency which are 90% or more high were obtained.

From these, it was confirmed that in the secondary battery of the present invention, the cycle characteristics and the first charge and discharge characteristics were improved regardless of the oxygen content in the negative electrode active material. In this case, it was also confirmed that both characteristics were improved more when oxygen content was 1.5 atomic% or more and 40 atomic% or less.

(Examples 6-1 to 6-3)

Silicon is deposited while intermittently introducing oxygen gas into the chamber, except that the negative electrode active material is formed so that the first oxygen-containing region and the second oxygen-containing region having a higher oxygen content are alternately stacked. The same procedure as in Example 1-6 was performed. At this time, the content of oxygen in the second oxygen-containing region is 5 atomic% and the number is one (Example 6-1), two (Example 6-2), or three ( Example 6-3) was set.

The cycle characteristics and the first charge / discharge characteristics of the secondary batteries of Examples 6-1 to 6-3 were examined, and the results shown in Table 8 and FIG. 14 were obtained.

As shown in Table 8 and FIG. 14, even when the negative electrode active material had the first and second oxygen-containing regions, the same results as in Table 1 were obtained. That is, in Examples 6-1 to 6-3 in which the crystal state of the negative electrode active material is crystalline, as in Example 1-6, compared with Comparative Examples 1-1 to 1-5, a high discharge capacity retention rate of 80% or more and First charge / discharge efficiency was obtained.

In particular, in Examples 1-6 and 6-1 to 6-3 in which the crystal state of the negative electrode active material is crystalline, as the number of the second oxygen-containing regions increases, the first charge and discharge efficiency is kept constant and the discharge capacity is maintained. The retention rate increased.

From these, in the secondary battery of this invention, even if a negative electrode active material has the 1st and 2nd oxygen containing area | region, it was confirmed that cycling characteristics and first charge / discharge characteristic improve. In this case, it was also confirmed that as the number of the second oxygen-containing regions increases, the cycle characteristics are further improved.

(Examples 7-1 to 7-16)

The same procedure as in Example 1-6 was carried out except that the negative electrode active material contained a metal element and the content thereof was in an alloy state. At this time, the kinds of metal elements were iron (Example 7-1), nickel (Example 7-2), molybdenum (Example 7-3), titanium (Example 7-4), and chromium (Example 7- 5), cobalt (Example 7-6), copper (Example 7-7), manganese (Example 7-8), zinc (Example 7-9), germanium (Example 7-10), aluminum ( Example 7-11), zirconium (Example 7-12), silver (Example 7-13), tin (Example 7-14), antimony (Example 7-15), or tungsten (Example 7- 16). Moreover, content of the metal element in the negative electrode active material was 5 atomic%.

The cycle characteristics and the first charge / discharge characteristics of the secondary batteries of Examples 7-1 to 7-16 were examined, and the results shown in Tables 9 and 10 were obtained.

As shown in Table 9 and Table 10, even when the negative electrode active material contained a metal element in an alloy state, the same results as in Table 1 were obtained. That is, in Examples 7-1 to 7-16 in which the crystal state of the negative electrode active material was crystalline, as in Example 1-6, a high discharge capacity retention rate and initial charge / discharge efficiency of 90% or more were obtained.

In particular, in Examples 7-1 to 7-16 in which the negative electrode active material contained a metal element, the discharge capacity retention rate and the first charge and discharge efficiency were higher than in Example 1-6 in which the negative electrode active material did not contain it.

From these, it was confirmed that in the secondary battery of the present invention, even when the negative electrode active material contains a metal element in an alloy state, the cycle characteristics and the first charge / discharge characteristics are improved.

(Examples 8-1 to 8-16)

The same procedure as in Examples 7-1 to 7-16 was carried out except that the negative electrode active material contained a metal element and the content thereof was changed to a compound (phase separation) state.

The cycle characteristics and the first charge / discharge characteristics of the secondary batteries of Examples 8-1 to 8-16 were examined, and the results shown in Tables 11 and 12 were obtained.

As shown in Table 11 and Table 12, even when the negative electrode active material contained a metal element in a compound state, the same results as in Table 1 were obtained. That is, in Examples 8-1 to 8-16 in which the crystal state of the negative electrode active material was crystalline, a high discharge capacity retention rate and initial charge / discharge efficiency of 90% or more were obtained in the same manner as in Example 1-6.

In particular, in Examples 8-1 to 8-16 in which the negative electrode active material contained a metal element, the discharge capacity retention rate and the first charge and discharge efficiency were higher than those in Example 1-6 in which the negative electrode active material did not contain it.

From these, it was confirmed that in the secondary battery of the present invention, even when the negative electrode active material contains a metal element to form a compound (phase separation) state, the cycle characteristics and the first charge / discharge characteristics are improved.

In addition, as apparent from the results of Tables 9 to 12, it was confirmed that when the negative electrode active material contained a metal element, the cycle characteristics and the first charge / discharge characteristics were improved regardless of whether the contained state was an alloy state or a compound state. .

(Examples 9-1 to 9-13)

The median diameter of the material for forming the negative electrode active material layer 54B is 1 μm (Example 9-1), 3 μm (Example 9-2), 5 μm (Example 9-3), 10 μm (Example 9- 4), 15 µm (Example 9-5), 20 µm (Example 9-6), 40 µm (Example 9-7), 50 µm (Example 9-8), 80 µm (Example 9- 9), 100 µm (Example 9-10), 150 µm (Example 9-11), 200 µm (Example 9-12), or 300 µm (Example 9-13), except that The same procedure as in Example 1-6 was performed.

The cycle characteristics and the first charge / discharge characteristics of the secondary batteries of Examples 9-1 to 9-13 were examined, and the results shown in Table 13 and FIG. 15 were obtained.

As shown in Table 13 and FIG. 15, even when the median diameter of the material for forming the negative electrode active material layer 54B was changed, the same results as in Table 1 were obtained. That is, in Examples 9-1 to 9-13 in which the crystal state of the negative electrode active material was crystalline, as in Example 1-6, a high discharge capacity retention rate and first charge and discharge efficiency were obtained.

In particular, in Examples 1-6 and 9-1 to 9-13 in which the crystal state of the negative electrode active material is crystalline, as the medium diameter increases, the initial charge and discharge efficiency increases while decreasing the discharge capacity retention rate. The trend was shown. In this case, when the median diameter was 5 µm or more and 200 µm or less, a 90% or more high discharge capacity retention rate and initial charge and discharge efficiency were obtained.

From these, in the secondary battery of this invention, even if the median diameter of the formation material of the negative electrode active material layer 54B was changed, it was confirmed that cycling characteristics and initial charge / discharge characteristics improve. In this case, it was also confirmed that the cycle characteristics were further improved when the median diameter was 5 µm or more and 200 µm or less.

(Examples 10-1 to 10-12)

The 10-point average roughness Rz of the surface of the negative electrode current collector 54A is 0.5 μm (Example 10-1), 1 μm (Example 10-2), 1.5 μm (Example 10-3), 2 μm ( Example 10-4), 3 μm (Example 10-5), 5 μm (Example 10-6), 15 μm (Example 10-7), 20 μm (Example 10-8), 25 μm ( Example 1-9, except that it changed to 30 micrometers (Example 10-10), 35 micrometers (Example 10-11), or 40 micrometers (Example 10-12). In the same order.

The cycle characteristics and the first charge / discharge characteristics of the secondary batteries of Examples 10-1 to 10-12 were examined, and the results shown in Table 14 and FIG. 16 were obtained.

As shown in Table 14 and FIG. 16, even when the ten-point average roughness Rz of the surface of the negative electrode current collector 54A was changed, the same results as in Table 1 were obtained. That is, in Examples 10-1 to 10-12 in which the crystal state of the negative electrode active material was crystalline, as in Example 1-6, a high discharge capacity retention rate and initial charge / discharge efficiency of 80% or more were obtained.

Particularly, in Examples 1-6 and 10-1 to 10-12 in which the crystal state of the negative electrode active material is crystalline, as the ten-point average roughness Rz increases, the charge capacity discharge rate decreases after the discharge capacity retention rate increases, and the first charge and discharge is performed. The efficiency tended to increase. In this case, when the ten-point average roughness Rz is 1.5 µm or more, the discharge capacity retention rate and the initial charge / discharge efficiency are higher, and when 3 µm or more and 30 µm or less, the high discharge capacity retention rate and the initial charge / discharge efficiency are 90% or more. Obtained.

From these, in the secondary battery of this invention, even if the 10-point average roughness Rz of the surface of the negative electrode collector 54A is changed, it was confirmed that cycling characteristics and initial charge / discharge characteristics improve. In this case, when the 10-point average roughness Rz was 1.5 micrometers or more, preferably 3 micrometers or more and 30 micrometers or less, it was also confirmed that both characteristics further improved.

(Example 11-1)

Examples 1-6, except that 4-fluoro-1,3-dioxolan-2-one (FEC), a cyclic carbonate having a halogen represented by the formula (2), was used as a solvent instead of EC. In the same order.

(Example 11-2)

As a solvent, the same procedure as in Example 1-6, except that 4,5-difluoro-1,3-dioxolan-2-one (DFEC), which is a cyclic carbonate having a halogen represented by the formula (2), was added Went through. At this time, the composition (EC: DFEC: DEC) of the solvent was 25: 5: 70 by weight ratio.

(Examples 11-3 and 11-4)

As a solvent, vinylene carbonate (VC: Example 11-3), which is a cyclic carbonate having an unsaturated bond represented by the formula (5), or vinylethylene carbonate (VEC: implemented, which is a cyclic carbonate having an unsaturated bond represented by the formula (6) The same procedure as in Example 11-1 was carried out except that Example 11-4) was added. At this time, content of VC etc. in a solvent was made into 1 weight%.

(Example 11-5)

The same procedure as in Example 11-1 was carried out except that lithium tetrafluoroborate (LiBF ₄ ) was added as the electrolyte salt. At this time, content of lithium hexafluorophosphate was 0.9 mol / kg with respect to a solvent, and content of lithium tetrafluoroborate was 0.1 mol / kg with respect to a solvent.

(Example 11-6)

The same procedure as in Example 11-1 was carried out except that sultone 1,3-furofensultone (PRS) was added. At this time, content of PRS in a solvent was made into 1 weight%.

(Examples 11-7 and 11-8)

Sulfobenzoic anhydride (SBAH: Example 11-7) which is an acid anhydride was used as the solvent. The procedure was the same as in Example 11-1 except that sulfopropionic anhydride (SPAH: Example 11-8) was added. At this time, content of SBAH etc. in the solvent liquid was made into 1 weight%.

The cycle characteristics, the first charge and discharge characteristics, and the expansion characteristics of the secondary batteries of Examples 11-1 to 11-8 were examined, and the results shown in Tables 15 and 16 were obtained.

As shown in Table 15 and Table 16, even when the composition of the solvent and the kind of the electrolyte salt were changed, the same results as in Table 1 were obtained. That is, in Examples 11-1 to 11-8 in which the crystal state of the negative electrode active material was crystalline, as in Example 1-6, a high discharge capacity retention ratio and initial charge / discharge efficiency of 90% or more were obtained.

In particular, Examples 11-1 to 11-8 in which a cyclic carbonate (FEC or DFEC) having a halogen, a cyclic carbonate having a unsaturated bond, a sultone or an acid anhydride are added as a solvent, or lithium tetrafluoroborate is added as an electrolyte salt. In Example 1-6, the discharge capacity retention rate was high, with the first charge and discharge efficiency being constant, compared with Example 1-6 without adding them. In the case of using a cyclic carbonate having a halogen, the discharge capacity retention ratio was higher in DFEC than in FEC.

In addition, in Example 11-6 to which PRS was added, the expansion ratio was significantly smaller than that of Example 1-6 to which it was not added.

In addition, only the result when the cyclic carbonate which has a halogen shown by Formula (2) and the cyclic carbonate which has an unsaturated bond shown by Formula (5) or (6) as a solvent is shown here, The halogen shown by Formula (1) is shown here. It does not show the result at the time of using the linear carbonate ester which has a C, and the cyclic carbonate which has an unsaturated bond shown in General formula (7). However, since the chain carbonate and the like having a halogen have a function of increasing the discharge capacity retention rate similarly to the cyclic carbonate and the like having a halogen, it is clear that the same result as in the case of the latter is obtained even when the former is used.

In addition, only the result at the time of using lithium hexafluorophosphate or lithium tetrafluoroborate as an electrolyte salt is shown here, The compound represented by Formula 8-Formula 10 or Formula 14-Formula 16 is shown. The result at the time of use is not shown. However, since lithium perchlorate or the like fulfills the function of increasing the discharge capacity retention rate like lithium hexafluorophosphate or the like, it is clear that the same result as in the latter case can be obtained even when the former is used.

From these, in the secondary battery of this invention, even if the composition of a solvent and the kind of electrolyte salt were changed, it was confirmed that cycling characteristics and initial charge / discharge characteristics improve. In this case, at least one of the chain carbonate ester having a halogen represented by the formula (1) and the cyclic carbonate ester having a halogen represented by the formula (2) as the solvent, or the cyclic group having a unsaturated bond represented by the formulas (5) to (7) It was also confirmed that the cycle characteristics were further improved by using carbonate ester, sultone or acid anhydride. As the electrolyte salt, at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate and lithium hexafluoroborate, the compound represented by the formulas (8) to (10), or the compound represented by the formulas (14) to (16), It was also confirmed that the cycle characteristics were further improved when used. In particular, it was confirmed that when sultone was used, the expansion characteristics were also improved.

(Example 12-1)

The procedure was the same as in Example 1-6, except that the rectangular secondary battery shown in Figs. 5 and 6 was manufactured in place of the laminate film secondary battery according to the following procedure.

First, after producing the positive electrode 21 and the negative electrode 22, the positive electrode lead 24 made of aluminum and the negative electrode lead 25 made of nickel are welded to the positive electrode current collector 21A and the negative electrode current collector 22A, respectively. It was. Subsequently, the positive electrode 21, the separator 23, and the negative electrode 22 were laminated in this order, wound in the long side direction, and then formed into a flat shape, thereby producing the battery element 20. Subsequently, after storing the battery element 20 in the battery can 11 made of aluminum, the insulating plate 12 was disposed on the battery element 20. Subsequently, the positive electrode lead 24 and the negative electrode lead 25 are welded to the positive electrode pin 15 and the battery can 11, respectively, and then the battery cover 13 is laser welded to the open end of the battery can 11. Fixed. Finally, an electrolyte solution was injected into the inside of the battery can 11 through the injection hole 19, and the injection hole 19 was closed by the sealing member 19A to complete the square battery.

(Example 12-2)

The same procedure as in Example 12-1 was carried out except that the iron battery can 11 was used in place of the aluminum battery can 11.

The cycle characteristics and the first charge / discharge characteristics of the secondary batteries of Examples 12-1 and 12-2 were examined, and the results shown in Table 17 were obtained.

As shown in Table 17, even when the battery structure was changed, the same results as in Table 1 were obtained. That is, in Examples 12-1 and 12-2 in which the crystal state of the negative electrode active material was crystalline, as in Example 1-6, a high discharge capacity retention rate and initial charge / discharge efficiency of 90% or more were obtained.

In particular, in the battery structures 12-1 and 12-2 each having a rectangular shape, the discharge capacity retention rate was increased while the initial charge and discharge efficiency was constant as compared with Example 1-6, which is a laminate film type. In addition, in the case of the square, when the battery can 11 is made of iron than in the case of aluminum, the discharge capacity retention rate is higher and the expansion rate is smaller.

In addition, although the specific example is not described here, in the case where the exterior member is a square made of a metal material, since the cycle characteristics and the expansion characteristics are improved compared to the laminate film type made of a film, the exterior member is made of a metallic material. It is clear that the same result is obtained also in the cylindrical secondary battery.

From these, in the secondary battery of this invention, even if the battery structure was changed, it was confirmed that cycling characteristics and initial charge / discharge characteristics improve. In this case, it was also confirmed that the cycle characteristics were further improved if the battery structure was a square or a cylinder.

From the results of Tables 1 to 17 and Figs. 11 to 16 described above, in the secondary battery of the present invention, the negative electrode active material layer of the negative electrode contains a crystalline negative electrode active material having silicon as a constituent element, By being connected, it was confirmed that the cycle characteristics and the first charge / discharge characteristics were improved without depending on the composition of the solvent, the type of the electrolyte salt, the battery structure, or the like.

As mentioned above, although embodiment and Example were given and this invention was demonstrated, this invention is not limited to the aspect demonstrated by embodiment and Example mentioned above, A various deformation | transformation is possible. For example, the use of the negative electrode of the present invention is not necessarily limited to a secondary battery, and other electrochemical devices other than the secondary battery may be used. As another use, a capacitor etc. are mentioned, for example.

In addition, although the above-mentioned embodiment and Example demonstrated the lithium ion secondary battery which displayed the capacity | capacitance of a negative electrode based on the occlusion and release | release of lithium as a kind of secondary battery, it is not necessarily limited to this. The secondary battery of the present invention includes a secondary battery whose capacity of the negative electrode is accompanied by the storage and release of lithium and the deposition and dissolution of lithium, and is represented by the sum of their capacity. Also in this regard, it is applicable. In this secondary main pond, a material capable of occluding and releasing lithium is used as the negative electrode active material, and the chargeable capacity of the negative electrode material capable of occluding and releasing lithium is set to be smaller than the discharge capacity of the positive electrode.

In addition, although the above-mentioned embodiment and Example demonstrated the case where a battery structure is a square, cylindrical shape, or a laminated film type, and the case where a battery element has a winding structure as an example, the secondary battery of this invention is a coin type or The same applies to the case of having another battery structure such as a button type or the case where the battery element has another structure such as a laminated structure.

In addition, in the above-described embodiments and examples, a partial sum using lithium as the electrode reaction material has been described, but other group 1 elements such as sodium (Na) or potassium (K), magnesium (Mg) or calcium ( Group 2 elements such as Ca) and other light metals such as aluminum may be used. Also in these cases, as the negative electrode active material, it is possible to use the negative electrode material described in the above embodiment.

Further, in the above-described embodiments and examples, regarding the half value width (2θ) of the diffraction peaks on the (111) crystal plane of the negative electrode active material obtained by X-ray diffraction, with respect to the negative electrode or the secondary battery of the present invention, Although the appropriate range derived from the result of the Example is described, the description does not completely deny the possibility that the half value width will fall out of the above range. That is, the said appropriate range is a range especially preferable for obtaining the effect of this invention to the last, and if the effect of this invention can be acquired, the half value width may deviate somewhat from the said range. This is the crystallite size attributable to the (111) crystal plane of the negative electrode active material obtained by X-ray diffraction, oxygen content in the negative electrode active material, 10-point average roughness Rz of the surface of the negative electrode current collector, or formation of the negative electrode active material layer. The same applies to the median diameter of the material.

The present invention claims priority of Japanese Patent Application No. 2008-100185 filed with the Japan Patent Office on April 8, 2008.

Those skilled in the art will be able to practice various modifications, combinations, partial combinations, and modifications according to design needs or other factors within the scope of the following claims or equivalents thereof.

1 is a cross-sectional view showing a configuration of a negative electrode according to an embodiment of the present invention.

A and B of FIG. 2 are SEM photographs showing the cross-sectional structure of the negative electrode shown in FIG. 1, and its schematic diagram.

3A and 3B are SEM photographs and schematic diagrams showing another cross-sectional structure of the negative electrode shown in FIG.

4A and 4B are SEM photographs showing another cross-sectional structure of the negative electrode shown in FIG. 1 and schematic diagrams thereof.

5 is a cross-sectional view showing a configuration of a first secondary battery provided with a negative electrode according to one embodiment of the present invention.

FIG. 6 is a cross-sectional view taken along a line VI-VI of the first secondary battery shown in FIG. 5. FIG.

7 is a cross-sectional view illustrating a configuration of a second secondary battery provided with a negative electrode according to one embodiment of the present invention.

FIG. 8 is an enlarged cross-sectional view showing a part of the wound electrode body shown in FIG. 7. FIG.

9 is a cross-sectional view showing a configuration of a third secondary battery provided with a negative electrode according to one embodiment of the present invention.

10 is a cross-sectional view taken along an X-X line of the wound electrode body shown in FIG. 9.

11 is a diagram showing a correlation between the half width and the discharge capacity retention rate and the first charge and discharge efficiency.

12 shows the correlation between crystallite size and discharge capacity retention and initial charge and discharge efficiency.

FIG. 13 shows a correlation between oxygen content, discharge capacity retention rate, and first charge / discharge efficiency. FIG.

FIG. 14 is a diagram showing a correlation between the number of second oxygen-containing regions, discharge capacity retention rate, and first charge / discharge efficiency. FIG.

FIG. 15 is a diagram showing a correlation between the median diameter of a material for forming a negative electrode active material layer, discharge capacity retention rate, and initial charge / discharge efficiency. FIG.

FIG. 16 is a diagram showing a correlation between a ten-point average roughness Rz, discharge capacity retention rate, and first charge / discharge efficiency. FIG.

(Explanation of symbols for the main parts of the drawing)

1, 22A, 42A, 54A: negative electrode current collector 2, 22B, 42B, 54B: negative electrode active material layer

2K: void 11, 31: battery can

12, 32, 33: insulation plate 13, 34: battery cover

14 terminal board 15 positive pin

16: insulation case 17, 37: gasket

18: cleavage valve 19: injection hole

19A: sealing member 20: battery element

21, 41, 53: positive electrode 21A, 41A, 53A: positive electrode current collector

21B, 41B, 53B: positive electrode active material layer 22, 42, 54: negative electrode

23, 43, 55: Separator 24, 45, 51: Positive electrode lead

25, 46, 52: negative electrode lead 35: safety valve mechanism

35A: disk plate 36: thermal resistance element

40, 50: wound electrode body 44: center pin

56: electrolyte 57: protective tape

61: contact film 60: exterior member

201: negative electrode active material particles 201P: flat particles

P1: contact portion P2: non-contact portion

Claims (20)

Positive electrode; Negative electrode; And Contains electrolyte, The negative electrode has a negative electrode active material layer on the negative electrode current collector, The negative electrode active material layer includes a crystalline negative electrode active material having silicon as a constituent element and is connected to the negative electrode current collector. The method of claim 1, Said negative electrode active material is at least 1 sort (s) of the crowd which consists of a single silicon, an alloy of silicon, and a compound of silicon. The method of claim 1, The said negative electrode active material layer contains the part which has a multilayered structure, The secondary battery characterized by the above-mentioned. The method of claim 1, Said negative electrode active material layer has a space | gap in the inside, The secondary battery characterized by the above-mentioned. The method of claim 1, The negative electrode active material layer has a portion in contact with the negative electrode current collector and a portion not in contact with the negative electrode current collector. The method of claim 1, The negative electrode active material has a plurality of particulate forms, and at least a part of the negative electrode active material has a flat shape in a direction along the surface of the negative electrode current collector. The method of claim 1, The half value width (2θ) of the diffraction peak on the (111) crystal plane of the negative electrode active material obtained by X-ray diffraction is 20 ° or less, A secondary battery, wherein the crystallite size resulting from the (111) crystal plane of the negative electrode active material obtained by X-ray diffraction is 10 nm or more. The method of claim 1, Said negative electrode active material has oxygen as a constituent element, and content of oxygen in the said negative electrode active material is 1.5 atomic% or more and 40 atomic% or less, The secondary battery characterized by the above-mentioned. The method of claim 1, The negative electrode active material has an oxygen containing region containing oxygen in the thickness direction thereof, and the content of oxygen in the oxygen containing region is higher than the content of oxygen in the other region. battery. The method of claim 1, The negative electrode active material may be iron (Fe), nickel (Ni), molybdenum (Mo), titanium (Ti), chromium (Cr), cobalt (Co), copper (Cu), manganese (Mn), zinc (Zn), Having as a constituent element at least one metal element of the group consisting of germanium (Ge), aluminum (Al), zirconium (Zr), silver (Ag), tin (Sn), antimony (Sb) and tungsten (W) A secondary battery characterized by the above-mentioned. The method of claim 1, The said negative electrode active material contains the part which has a metal element as a structural element, and the part is an alloy state or a compound state, The secondary battery characterized by the above-mentioned. The method of claim 1, The said negative electrode active material layer is formed by the spray method, The secondary battery characterized by the above-mentioned. The method of claim 1, The secondary battery having a ten-point average roughness Rz of the surface of the negative electrode current collector is 1.5 µm or more. The method of claim 1, The electrolyte solution may be an unsaturated bond represented by at least one of a chain carbonate ester having a halogen represented by the following formula (1) as a constituent element and a cyclic carbonate ester having a halogen represented by the formula (2) as a constituent element, formulas (5) to (7). A secondary battery comprising a solvent containing a cyclic carbonate, a sultone, and an acid anhydride. [Formula 1]

(R11 to R16 is a hydrogen group, a halogen group, an alkyl group or a halogenated alkyl group, at least one of them is a halogen group or a halogenated alkyl group) [Formula 2]

(R17 to R20 is a hydrogen group, a halogen group, an alkyl group or a halogenated alkyl group, at least one of them is a halogen group or a halogenated alkyl group) [Formula 5]

(R21 and R22 is a hydrogen group or an alkyl group) [Formula 6]

(R23 to R26 is a hydrogen group, an alkyl group, a vinyl group or an allyl group, at least one of them is a vinyl group or an allyl group) [Formula 7]

(R27 is an alkylene group) The method of claim 14, The linear carbonate ester having a halogen represented by the formula (1) as a constituent element is fluoromethylmethyl carbonate, bis (fluoromethyl) or difluoromethylmethyl carbonate, and the halogen represented by the formula (2) as a constituent element The cyclic carbonate ester having is 4-fluoro-1,3-dioxolan-2-one or 4,5-difluoro-1,3-dioxolan-2-one, and is an unsaturated bond represented by the above formula (3). The cyclic carbonate having a carbonate is vinylene carbonate, the cyclic carbonate having an unsaturated bond represented by the formula (4) is vinyl ethylene, and the cyclic carbonate having an unsaturated bond represented by the formula (5) is methylene ethylene The secondary battery characterized by the above-mentioned. The method of claim 1, The electrolyte solution is lithium hexafluorophosphate (LiPF ₆ ), lithium tetrafluoroborate () LiBF ₄ , lithium perchlorate (LiClO ₄ ) and lithium hexafluorophosphate (LiAsF ₆ ), a compound represented by the following formula 8 to formula 10, A secondary battery comprising an electrolyte salt containing at least one kind of a group consisting of a compound represented by the following formulas (14) to (16). [Formula 8]

(X31 is a group 1 element or group 2 element, or aluminum (Al) in the long period type table, and M31 is a transition metal element, or a group 13 element, group 14 element, or group 15 element in the long period type table) R31 is a halogen group, Y31 is-(O =) C-R32-C (= O)-,-(O =) CC (R33) ₂ -or-(O =) CC (= O)- R32 is an alkylene group, a halogenated alkylene group, an arylene group or a halogenated arylene group, R33 is an alkyl group, a halogenated alkyl group, an aryl group or a halogenated aryl group, a3 is an integer of 1 to 4, b3 is 0, 2 or 4 , c3, d3, m3 and n3 are integers of 1 to 3) [Formula 9]

(X41 is a Group 1 or Group 2 element in the long-period periodic table, M41 is a transition metal element or a Group 13 element, Group 14 or Group 15 element in the long-periodical periodic table, and 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- , R41 and R43 are 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, R42 is a hydrogen group, an alkyl group, a halogen group or a halogenated alkyl group, a4, e4 and n4 are 1 or 2, and b4 and d4 are 1 to 2 Is an integer of 4, c4 is an integer of 0 to 4, f4 and m4 are an integer of 1 to 3) [Formula 10]

(X51 is a Group 1 or Group 2 element in the long-period periodic table, M51 is a transition metal element or a Group 13 element, Group 14 or Group 15 element in the long-periodical periodic table, and Rf is a carbon number A fluorinated alkyl group having 1 to 10 carbon atoms or a fluorinated aryl group 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- , R51 is a hydrogen group, an alkyl group, a halogen group or a halogenated alkyl group, 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 A5, f5 and n5 are 1 or 2, b5, c5 and e5 are integers from 1 to 4, d5 is an integer from 0 to 4, g5 and m5 are integers from 1 to 3) [Formula 14]

(m and n are integers of 1 or more) [Formula 15]

(R61 is a C2-C4 straight or branched perfluoroalkylene group) [Formula 16]

(p, q, and r are integers of 1 or more) The method of claim 16, The compound represented by the formula (8) is a compound represented by the following formula (1) to (6), and the compound represented by the formula (9) is a compound represented by the formula (1) to (8) The compound represented by the formula (10) is a compound represented by the formula (13). [Formula 11]

[Formula 12]

[Formula 13]

The method of claim 1, The secondary battery is characterized in that the positive electrode, the negative electrode, and the electrolyte solution are housed inside a cylindrical or rectangular exterior member. The method of claim 1, The exterior member contains iron or an iron alloy. In a negative electrode having a negative electrode active material layer on a negative electrode current collector, The negative electrode active material layer includes a crystalline negative electrode active material having silicon as a constituent element and is connected to the negative electrode current collector.

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