JP2008053054A - Battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery using a positive electrode active material containing lithium which demonstrates superior high-temperature characteristics. <P>SOLUTION: The battery includes a positive electrode 21 and a negative electrode 22 as well as an electrolytic solution, and the positive electrode 21 contains a positive electrode active material of which average composition is expressed as LiCo<SB>0.33</SB>Ni<SB>0.33</SB>Mn<SB>0.33</SB>O<SB>2</SB>, LiMn<SB>2</SB>O<SB>4</SB>, or LiFePO<SB>4</SB>or the like. An electrolytic solution containing difluoroethylene carbonate is impregnated in a separator 23 installed between the positive electrode 21 and the negative electrode 22. Thereby, chemical stability at high temperature can be improved and superior high-temperature characteristics can be obtained. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a battery using a positive electrode active material containing lithium (Li).

In recent years, many portable electronic devices such as notebook portable computers, cellular phones, and camera-integrated VTRs (video tape recorders) have appeared, and their weight and size have been reduced. Accordingly, as a power source for these portable electronic devices, development of a secondary battery that is lightweight and capable of obtaining a high energy density is in progress. As a secondary battery capable of obtaining a high energy density, for example, a lithium secondary battery is known. As this lithium secondary battery, for example, a battery using a lithium composite oxide such as lithium cobaltate for the positive electrode and a carbon material such as graphite for the negative electrode has been widely put into practical use (for example, see Patent Document 1). .
Japanese Patent Laid-Open No. 3-129664

  However, as portable electronic devices are increasingly used, recently, they are often placed under high temperature conditions during transportation or use, resulting in a problem of deterioration of battery characteristics. Accordingly, it has been desired to develop a battery capable of obtaining excellent characteristics not only at room temperature but also at high temperatures.

  The present invention has been made in view of such problems, and an object thereof is to provide a battery that exhibits excellent high-temperature characteristics.

A battery according to the present invention includes an electrolyte solution together with a positive electrode and a negative electrode, and the positive electrode contains at least one of positive electrode active materials whose average composition is represented by chemical formula 1, chemical formula 2 and chemical formula 3. The electrolytic solution contains difluoroethylene carbonate.
(Chemical formula 1)
Li _f Co _g Ni _h Mn _j M1 _k O _(2-m) X1 _n
(In the formula, M1 is magnesium (Mg), aluminum (Al), boron (B), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), copper (Cu), zinc (Zn ), Zirconium (Zr), molybdenum (Mo), tin (Sn), calcium (Ca), strontium (Sr) and tungsten (W), and X1 is fluorine (F), At least one member selected from the group consisting of chlorine (Cl) and bromine (Br), where f, g, h, j, k, m, and n are 0.8 ≦ f ≦ 1.2 and 0 ≦ g <. 1, 0 <h ≦ 1, 0 ≦ j <1, 0 ≦ k ≦ 0.1, g + h + j + k = 1, −0.1 ≦ m ≦ 0.2, 0 ≦ n ≦ 0.1 is there.)
(Chemical formula 2)
Li _v Mn _2-w M2 _w O _x X2 _y
(Wherein M2 is selected from the group consisting of cobalt (Co), nickel (Ni), magnesium, aluminum, boron, titanium, vanadium, chromium, iron, copper, zinc, molybdenum, tin, calcium, strontium and tungsten). X2 is at least one selected from the group consisting of fluorine, chlorine and bromine, and v, w, x and y are 0.9 ≦ v ≦ 1.1, 0 ≦ w ≦ 0. (6, 3.7 ≦ x ≦ 4.1, 0 ≦ y ≦ 0.1)
(Chemical formula 3)
Li _z M3PO ₄
(Wherein M3 is a group consisting of cobalt, manganese (Mn), iron, nickel, magnesium, aluminum, boron, titanium, vanadium, niobium (Nb), copper, zinc, molybdenum, calcium, strontium, tungsten and zirconium. (Z is a value in the range of 0.9 ≦ z ≦ 1.1.)

  In the battery of the present invention, since the positive electrode contains at least one of the positive electrode active materials represented by chemical formula 1, chemical formula 2 and chemical formula 3, high energy density is obtained and excellent high temperature characteristics are obtained. . Furthermore, since difluoroethylene carbonate is contained in the electrolytic solution, decomposition of the electrolytic solution accompanying charge / discharge is suppressed.

  According to the battery of the present invention, the positive electrode active material described above is included in the positive electrode, and difluoroethylene carbonate is included in the electrolytic solution. Therefore, chemical stability at high temperatures can be improved, and excellent high temperature characteristics can be obtained. Obtainable.

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

(First embodiment)
FIG. 1 shows a cross-sectional configuration of the secondary battery according to the first embodiment of the present invention. This secondary battery is a so-called lithium ion secondary battery in which the capacity of the negative electrode is represented by a capacity component due to insertion and extraction of lithium. This secondary battery is a so-called cylindrical type, and a wound electrode body 20 in which a belt-like positive electrode 21 and a negative electrode 22 are wound through a separator 23 inside a substantially hollow cylindrical battery can 11. have. The battery can 11 is made of, for example, iron plated with nickel, and has one end closed and the other end open. Inside the battery can 11, a pair of insulating plates 12, 13 are arranged perpendicular to the winding peripheral surface so as to sandwich the winding electrode body 20.

  At the open end of the battery can 11, a battery lid 14, a safety valve mechanism 15 provided inside the battery lid 14 and a heat sensitive resistance element (Positive Temperature Coefficient; PTC element) 16 are interposed via a gasket 17. It is attached by caulking, and the inside of the battery can 11 is sealed. The battery lid 14 is made of, for example, the same material as the battery can 11. The safety valve mechanism 15 is electrically connected to the battery lid 14 via the heat sensitive resistance element 16, and the disk plate 15A is reversed when the internal pressure of the battery exceeds a certain level due to an internal short circuit or external heating. Thus, the electrical connection between the battery lid 14 and the wound electrode body 20 is cut off. When the temperature rises, the heat sensitive resistance element 16 limits the current by increasing the resistance value and prevents abnormal heat generation due to a large current. The gasket 17 is made of, for example, an insulating material, and asphalt is applied to the surface.

  For example, a center pin 24 is inserted in the center of the wound electrode body 20. A positive electrode lead 25 made of aluminum or the like is connected to the positive electrode 21 of the spirally wound electrode body 20, and a negative electrode lead 26 made of nickel or the like is connected to the negative electrode 22. The positive electrode lead 25 is electrically connected to the battery lid 14 by being welded to the safety valve mechanism 15, and the negative electrode lead 26 is welded to and electrically connected to the battery can 11.

  FIG. 2 shows an enlarged part of the spirally wound electrode body 20 shown in FIG. The positive electrode 21 has, for example, a structure in which a positive electrode active material layer 21B is provided on both surfaces of a positive electrode current collector 21A having a pair of opposed surfaces. The positive electrode current collector 21A is made of, for example, a metal foil such as an aluminum foil, a nickel foil, or a stainless steel foil.

  The positive electrode active material layer 21 </ b> B includes at least one of positive electrode active materials whose average composition is represented by Chemical Formula 4, Chemical Formula 5 and Chemical Formula 6. This is because if these positive electrode active materials are used, a high energy density can be obtained and high-temperature characteristics can be improved. In addition, these positive electrode active materials do not need to have a uniform composition as a whole, and the content of the constituent elements may partially change. For example, if a particulate positive electrode active material is used, the composition may be different between the inside and the surface of the particle.

(Chemical formula 4)
Li _f Co _g Ni _h Mn _j M1 _k O _(2-m) X1 _n
In the formula, M1 is at least one selected from the group consisting of magnesium, aluminum, boron, titanium, vanadium, chromium, iron, copper, zinc, zirconium, molybdenum, tin, calcium, strontium, and tungsten, and X1 is fluorine. , At least one of the group consisting of chlorine and bromine. f, g, h, j, k, m and n are 0.8 ≦ f ≦ 1.2, 0 ≦ g <1, 0 <h ≦ 1, 0 ≦ j <1, 0 ≦ k ≦ 0.1. , G + h + j + k = 1, −0.1 ≦ m ≦ 0.2, 0 ≦ n ≦ 0.1. That is, this positive electrode active material contains lithium, nickel, and oxygen as essential constituent elements, and the basic structure is a layered rock salt structure. Note that the composition of lithium varies depending on the state of charge and discharge, and the value of f represents a value in a fully discharged state.

(Chemical formula 5)
Li _v Mn _2-w M2 _w O _x X2 _y
In the formula, M2 is at least one selected from the group consisting of cobalt, nickel, magnesium, aluminum, boron, titanium, vanadium, chromium, iron, copper, zinc, molybdenum, tin, calcium, strontium, and tungsten, and X2 Is at least one member selected from the group consisting of fluorine, chlorine and bromine. v, w, x and y are values in the range of 0.9 ≦ v ≦ 1.1, 0 ≦ w ≦ 0.6, 3.7 ≦ x ≦ 4.1, 0 ≦ y ≦ 0.1. is there. That is, this positive electrode active material contains lithium, manganese, and oxygen as essential constituent elements, and the basic structure is a spinel structure. Note that the composition of lithium varies depending on the state of charge and discharge, and the value of v represents a value in a fully discharged state.

(Chemical formula 6)
Li _z M3PO ₄
In the formula, M3 is at least one selected from the group consisting of cobalt, manganese, iron, nickel, magnesium, aluminum, boron, titanium, vanadium, niobium, copper, zinc, molybdenum, calcium, strontium, tungsten and zirconium. . z is a value in the range of 0.9 ≦ z ≦ 1.1. That is, this positive electrode active material contains lithium, M3, phosphorus, and oxygen as essential constituent elements, and the basic structure is an olivine structure. Note that the composition of lithium varies depending on the state of charge and discharge, and the value of z represents a value in a fully discharged state.

Specific examples of such a compound include lithium nickel composite oxide (Li _f NiO ₂ ), lithium nickel cobalt composite oxide (Li _f Co _g Ni _h O ₂ ), lithium nickel manganese composite oxide (Li _f Ni _h Mn _j O ₂ ), lithium nickel cobalt manganese composite oxide (Li _f Co _g Ni _h Mn _j O ₂ ), lithium manganese composite oxide having a spinel structure (Li _v Mn ₂ O ₄ ), lithium iron phosphate compound (Li _z FePO ₄₎ and a lithium-iron-manganese phosphate compound _{(Li z Fe 1-u Mn} u PO 4 (u <1)) and the like. Among them, the compound having the composition shown in Chemical Formula 4 preferably contains at least nickel and manganese, and the nickel composition h and the manganese composition j have a relationship of h ≧ j, and in particular, cobalt, nickel and manganese. And their composition g, h, j is preferably 1: 1: 1. This is because higher characteristics can be obtained.

  The positive electrode active material layer 21 </ b> B may also contain a conductive material such as a carbon material and a binder such as polyvinylidene fluoride as necessary, and may further include one or more other positive electrode active materials. It may be mixed and contained. Examples of other positive electrode active materials include those having an average composition represented by Chemical formula 7. This positive electrode active material does not need to have a uniform composition as a whole, and the content of the constituent elements may partially change.

(Chemical formula 7)
_{Li p Co q M4 r O (} 2-s) X1 t
In the formula, M4 is at least one member selected from the group consisting of magnesium, aluminum, boron, titanium, vanadium, chromium, iron, copper, zinc, zirconium, molybdenum, tin, calcium, strontium, and tungsten, and X1 is fluorine. , At least one of the group consisting of chlorine and bromine. p, q, r, s and t are 0.8 ≦ p ≦ 1.2, 0.9 ≦ q ≦ 1, 0 ≦ r ≦ 0.1, q + r = 1, −0.1 ≦ s ≦ 0. 2, 0 ≦ t ≦ 0.1. That is, this positive electrode active material contains lithium, cobalt, and oxygen as essential constituent elements, and the basic structure is a layered rock salt structure. Note that the composition of lithium varies depending on the state of charge and discharge, and the value of p represents a value in a fully discharged state.

  When a positive electrode active material whose average composition is represented by chemical formula 4, chemical formula 5 or chemical formula 6 is mixed with another positive electrode active material, a positive electrode active material represented by chemical formula 4, chemical formula 5 or chemical formula 6 Is preferably in the range of 5% by mass to 100% by mass, more preferably in the range of 10% by mass to 100% by mass, and further in the range of 10% by mass to 50% by mass. It is more preferable if it is inside. This is because a higher effect can be obtained.

  The negative electrode 22 has, for example, a structure in which a negative electrode active material layer 22B is provided on both surfaces of a negative electrode current collector 22A having a pair of opposed surfaces. The negative electrode current collector 22A is made of, for example, a metal foil such as a copper foil, a nickel foil, or a stainless steel foil.

  The negative electrode active material layer 22B includes, for example, any one or more of negative electrode materials capable of inserting and extracting lithium as a negative electrode active material. Examples of the negative electrode material capable of inserting and extracting lithium include a material containing silicon (Si) or tin as a constituent element. Silicon or tin has a large ability to occlude and release lithium, and a high energy density can be obtained.

  As such a negative electrode material, specifically, a simple substance, alloy, or compound of silicon, a simple substance, alloy, or compound of tin, or a material that has at least one phase of one or more of these phases Is mentioned. Note that alloys include those containing one or more metal elements and one or more metalloid elements in addition to those composed of two or more metal elements. Moreover, the nonmetallic element may be included. There are structures in which a solid solution, a eutectic (eutectic mixture), an intermetallic compound, or two or more of them coexist.

  Examples of the silicon alloy include, as the second constituent element other than silicon, tin, nickel, copper, iron, cobalt, manganese, zinc, indium (In), silver (Ag), titanium, germanium (Ge), and bismuth. Examples include those containing at least one of the group consisting of (Bi), antimony (Sb), and chromium. As an alloy of tin, for example, as a second constituent element other than tin, among the group consisting of silicon, nickel, copper, iron, cobalt, manganese, zinc, indium, silver, titanium, germanium, bismuth, antimony and chromium The thing containing at least 1 sort (s) of these is mentioned.

  Examples of the silicon compound or tin compound include those containing oxygen (O) or carbon (C), and may contain the second constituent element described above in addition to silicon or tin.

  As this negative electrode material, tin, cobalt, and carbon are included as constituent elements, the carbon content is 9.9 mass% or more and 29.7 mass% or less, and cobalt is based on the total of tin and cobalt. A CoSnC-containing material having a ratio Co / (Sn + Co) of 30% by mass to 70% by mass is preferable. This is because a high energy density can be obtained in such a composition range, and excellent cycle characteristics can be obtained.

  This CoSnC-containing material may further contain other constituent elements as necessary. As other constituent elements, for example, silicon, iron, nickel, chromium, indium, niobium, germanium, titanium, molybdenum, aluminum, phosphorus (P), gallium (Ga) or bismuth is preferable, and two or more kinds are included. Also good. This is because the capacity or cycle characteristics can be further improved.

  This CoSnC-containing material has a phase containing tin, cobalt, and carbon, and this phase preferably has a low crystallinity or an amorphous structure. In this CoSnC-containing material, it is preferable that at least a part of carbon as a constituent element is bonded to a metal element or a semimetal element as another constituent element. The decrease in cycle characteristics is considered to be due to aggregation or crystallization of tin or the like, but such aggregation or crystallization can be suppressed by combining carbon with other elements.

  As a measuring method for examining the bonding state of elements, for example, X-ray photoelectron spectroscopy (XPS) can be cited. In XPS, the peak of the carbon 1s orbital (C1s) appears at 284.5 eV in an energy calibrated apparatus so that the peak of the gold atom 4f orbital (Au4f) is obtained at 84.0 eV if it is graphite. . Moreover, if it is surface contamination carbon, it will appear at 284.8 eV. On the other hand, when the charge density of the carbon element increases, for example, when carbon is bonded to a metal element or a metalloid element, the C1s peak appears in a region lower than 284.5 eV. That is, when the peak of the synthetic wave of C1s obtained for the CoSnC-containing material appears in a region lower than 284.5 eV, at least a part of the carbon contained in the CoSnC-containing material is a metal element or a half of other constituent elements. Combined with metal elements.

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

  As a negative electrode material capable of inserting and extracting lithium, for example, a material containing another metal element or other metalloid element capable of forming an alloy with lithium as a constituent element can also be used. Examples of such metal elements or metalloid elements include magnesium, boron, aluminum, gallium, indium, germanium, lead (Pb), bismuth, cadmium (Cd), silver, zinc, hafnium (Hf), zirconium, yttrium (Y ), Palladium (Pd) or platinum (Pt).

  As a negative electrode material capable of inserting and extracting lithium, for example, a carbon material such as graphite, non-graphitizable carbon, or graphitizable carbon may be used. The negative electrode material may be used together. The carbon material has very little change in crystal structure due to insertion and extraction of lithium. For example, when used together with the negative electrode material described above, a high energy density and excellent cycle characteristics can be obtained. It is also preferable because it functions as a conductive agent.

  The negative electrode active material layer 22B may also include other materials that do not contribute to charging, such as a conductive agent, a binder, or a viscosity modifier. Examples of the conductive agent include graphite fiber, metal fiber, and metal powder. Examples of the binder include a fluorine-based polymer compound such as polyvinylidene fluoride, or a synthetic rubber such as styrene butadiene rubber or ethylene propylene diene rubber. Examples of the viscosity modifier include carboxymethylcellulose.

  Note that in this embodiment, by adjusting the amount of the positive electrode active material and the negative electrode material capable of inserting and extracting lithium, lithium can be stored and released rather than the charge capacity of the positive electrode active material. The charge capacity of the possible negative electrode material is increased so that lithium metal does not deposit on the negative electrode 22 even during full charge.

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

  The separator 23 is impregnated with an electrolytic solution. The electrolytic solution contains, for example, a solvent and an electrolyte salt dissolved in the solvent, and the solvent contains difluoroethylene carbonate.

  Examples of the difluoroethylene carbonate include 4,4-difluoro-1,3-dioxolan-2-one, cis-4,5-difluoro-1,3-dioxolan-2-one, and trans-4,5-difluoro- 1,3-dioxolan-2-one may be mentioned. Of these, trans-4,5-difluoro-1,3-dioxolan-2-one is preferred. This is because a higher effect can be obtained.

  As the solvent, in addition to the above, one or more other solvents may be mixed and used. Examples of other solvents include ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, 1,2-dimethoxyethane, 1,2-diethoxyethane, γ-butyrolactone, tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxolane, 4-methyl-1,3-dioxolane, vinylene carbonate, 4-vinyl-1,3-dioxolan-2-one, dimethyl ether, acetonitrile, ptopionitrile, acetate ester, butyrate ester, propionate ester, etc. The nonaqueous solvent of these is mentioned. Among these, it is more preferable to use a mixture with vinylene carbonate. This is because the chemical stability at high temperatures can be further improved. It is also preferable to use a mixture with a low-viscosity solvent having a viscosity of 1 mPa · s or less, such as dimethyl carbonate, diethyl carbonate, or methyl ethyl carbonate. This is because the ion conductivity can be further improved.

Examples of the electrolyte salt include lithium hexafluorophosphate (LiPF ₆ ), lithium tetrafluoroborate (LiBF ₄ ), lithium hexafluoroarsenate (LiAsF ₆ ), lithium perchlorate (LiClO ₄ ), trifluoro. Lithium methanesulfonate (CF ₃ SO ₃ Li), bis [trifluoromethanesulfonyl] imidolithium ((CF ₃ SO ₂ ) ₂ NLi), tris [trifluoromethanesulfonyl] methyl lithium ((CF ₃ SO ₂ ) ₃ CLi), Examples thereof include lithium salts such as bis (pentafluoroethanesulfonyl) imidolithium ((C ₂ F ₅ SO ₂ ) ₂ NLi) or lithium bisoxalate borate (LiB (C ₂ O ₄ ) ₂ ). Any one electrolyte salt may be used alone, or two or more electrolyte salts may be mixed and used.

  For example, the secondary battery can be manufactured as follows.

  First, for example, the positive electrode active material layer 21B is formed on the positive electrode current collector 21A to produce the positive electrode 21. The positive electrode active material layer 21B is prepared, for example, by mixing the above-described positive electrode active material powder, a conductive agent, and a binder to prepare a positive electrode mixture. The positive electrode mixture is then mixed with N-methyl-2-pyrrolidone or the like. It is formed by dispersing in a solvent to obtain a paste-like positive electrode mixture slurry, applying the positive electrode mixture slurry to the positive electrode current collector 21A, drying, and compression molding. Further, for example, in the same manner as the positive electrode 21, the negative electrode active material layer 22 </ b> B is formed on the negative electrode current collector 22 </ b> A to produce the negative electrode 22.

  Next, the positive electrode lead 25 is attached to the positive electrode current collector 21A by welding or the like, and the negative electrode lead 26 is attached to the negative electrode current collector 22A by welding or the like. Subsequently, the positive electrode 21 and the negative electrode 22 are wound through the separator 23, and the tip of the positive electrode lead 25 is welded to the safety valve mechanism 15, and the tip of the negative electrode lead 26 is welded to the battery can 11. The positive electrode 21 and the negative electrode 22 are sandwiched between a pair of insulating plates 12 and 13 and stored in the battery can 11. After the positive electrode 21 and the negative electrode 22 are accommodated in the battery can 11, an electrolytic solution containing difluoroethylene carbonate is injected into the battery can 11 and impregnated in the separator 23. After that, the battery lid 14, the safety valve mechanism 15 and the heat sensitive resistance element 16 are fixed by caulking through the gasket 17 at the opening end of the battery can 11. Thereby, the secondary battery shown in FIGS. 1 and 2 is completed.

  In the secondary battery, when charged, for example, lithium ions are extracted from the positive electrode 21 and inserted in the negative electrode 22 through the electrolytic solution. On the other hand, when discharging is performed, for example, lithium ions are extracted from the negative electrode 22 and inserted in the positive electrode 21 through the electrolytic solution. In that case, since the positive electrode active material mentioned above is contained in the positive electrode 21, a high energy density is obtained and a high temperature characteristic is obtained. Furthermore, since difluoroethylene carbonate is contained in the electrolytic solution, a dense coating is formed on the electrode surface, suppressing decomposition of the electrolytic solution and obtaining high chemical stability even at high temperatures.

  Thus, according to the present embodiment, the positive electrode 21 contains at least one of the positive electrode active materials whose average composition is represented by chemical formula 4, chemical formula 5 and chemical formula 6, and the electrolytic solution contains difluoroethylene carbonate. As a result, chemical stability at high temperatures can be improved, and excellent high temperature characteristics can be obtained.

  Next, other embodiments of the present invention will be described. Components that are the same as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

(Second Embodiment)
The secondary battery according to the second embodiment has a negative electrode active material layer 22B formed using a vapor phase method, a liquid phase method, a firing method, or two or more of these methods. The secondary battery has the same configuration, operation, and effects as those of the first embodiment except that the secondary battery has the negative electrode active material layer 22B formed by any of these methods. It can be manufactured in the same manner.

  The negative electrode active material layers 22B formed on both surfaces of the negative electrode current collector 22A are preferably alloyed at least at a part of the interface with the negative electrode current collector 22A. Specifically, it is preferable that the constituent element of the negative electrode current collector 22A is diffused in the negative electrode active material layer 22B, the constituent element of the negative electrode active material is diffused in the negative electrode current collector 22A, or they are mutually diffused at the interface. This is because breakage due to expansion / contraction of the negative electrode active material layer 22B due to charging / discharging can be suppressed, and electronic conductivity between the negative electrode active material layer 22B and the negative electrode current collector 22A can be improved. .

  Further, as the vapor phase method, for example, a physical deposition method or a chemical deposition method can be used. Specifically, a vacuum deposition method, a sputtering method, an ion plating method, a laser ablation method, a thermal chemical vapor deposition ( Examples include CVD (Chemical Vapor Deposition), plasma chemical vapor deposition, and thermal spraying. As the liquid phase method, a known method such as electroplating or electroless plating can be used. The firing method is, for example, a method in which a particulate negative electrode active material is mixed with a binder, dispersed in a solvent, applied, and then heat-treated at a temperature higher than the melting point of the binder. A known method can also be used for the firing method, for example, an atmospheric firing method, a reactive firing method, or a hot press firing method.

  The negative electrode active material layer 22B formed by the above-described method contains, for example, a negative electrode active material containing silicon or tin as a constituent element. Specifically, for example, it contains a simple substance, an alloy, or a compound of silicon, or a simple substance, an alloy, or a compound of tin, and may contain two or more of them.

(Third embodiment)
The secondary battery according to the third embodiment is a so-called lithium metal secondary battery in which the capacity of the negative electrode 22 is represented by a capacity component due to precipitation and dissolution of lithium. This secondary battery has the same configuration and effects as those of the first embodiment except that the negative electrode active material layer 22B is made of lithium metal, and can be manufactured in the same manner.

  That is, this secondary battery uses lithium metal as a negative electrode active material, and thereby can obtain a high energy density. The negative electrode active material layer 22B may be configured to be already provided from the time of assembly, but may be configured by lithium metal which is not present at the time of assembly and is deposited during charging. Alternatively, the negative electrode active material layer 22B may be used as a current collector, and the negative electrode current collector 22A may be deleted.

  In the secondary battery, when charged, for example, lithium ions are extracted from the positive electrode 21 and deposited as lithium metal on the surface of the negative electrode current collector 22A through the electrolytic solution. When the discharge is performed, for example, lithium metal is eluted as lithium ions from the negative electrode active material layer 22B, and is occluded in the positive electrode 21 through the electrolytic solution. Also in this secondary battery, high chemical stability can be obtained at high temperature by using the positive electrode active material described above for the positive electrode 21 and including difluoroethylene carbonate in the electrolytic solution.

(Fourth embodiment)
FIG. 3 shows the configuration of the secondary battery according to the fourth embodiment. This secondary battery is a so-called laminate film type, and has a wound electrode body 30 to which a positive electrode lead 31 and a negative electrode lead 32 are attached accommodated in a film-shaped exterior member 40.

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

  The exterior member 40 is made of, for example, a rectangular aluminum laminated film in which a nylon film, an aluminum foil, and a polyethylene film are bonded together in this order. For example, the exterior member 40 is disposed so that the polyethylene film side and the wound electrode body 30 face each other, and the outer edge portions are in close contact with each other by fusion bonding or an adhesive. An adhesive film 41 is inserted between the exterior member 40 and the positive electrode lead 31 and the negative electrode lead 32 to prevent intrusion of outside air. The adhesion film 41 is made of a material having adhesion to the positive electrode lead 31 and the negative electrode lead 32, for example, a polyolefin resin such as polyethylene, polypropylene, modified polyethylene, or modified polypropylene.

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

  FIG. 4 shows a cross-sectional structure taken along line II of the spirally wound electrode body 30 shown in FIG. The electrode winding body 30 is obtained by laminating a positive electrode 33 and a negative electrode 34 via a separator 35 and an electrolyte layer 36 and winding them, and the outermost periphery is protected by a protective tape 37.

  The positive electrode 33 has a structure in which a positive electrode active material layer 33B is provided on both surfaces of a positive electrode current collector 33A. The negative electrode 34 has a structure in which a negative electrode active material layer 34B is provided on both surfaces of a negative electrode current collector 34A, and the negative electrode active material layer 34B and the positive electrode active material layer 33B are arranged to face each other. The configuration of the positive electrode current collector 33A, the positive electrode active material layer 33B, the negative electrode current collector 34A, the negative electrode active material layer 34B, and the separator 35 is the same as that of the positive electrode current collector 21A, positive electrode active This is the same as the material layer 21B, the negative electrode current collector 22A, the negative electrode active material layer 22B, and the separator 23.

  The electrolyte layer 36 includes an electrolytic solution and a polymer compound serving as a holding body that holds the electrolytic solution, and has a so-called gel shape. A gel electrolyte is preferable because high ion conductivity can be obtained and battery leakage can be prevented. The configuration of the electrolytic solution is the same as that of the first embodiment. Examples of the polymer compound include, for example, an ether polymer compound such as polyethylene oxide or a crosslinked product containing polyethylene oxide, an ester polymer compound such as polymethacrylate, or an acrylate polymer compound, or polyvinylidene fluoride or vinylidene fluoride. Examples thereof include polymers of vinylidene fluoride such as a copolymer with hexafluoropropylene, and any one of these or a mixture of two or more thereof is used. In particular, from the viewpoint of redox stability, it is desirable to use a fluorine-based polymer compound such as a vinylidene fluoride polymer.

  For example, the secondary battery can be manufactured as follows.

  First, a precursor solution containing an electrolytic solution, a polymer compound, and a mixed solvent is applied to each of the positive electrode 33 and the negative electrode 34, and the mixed solvent is volatilized to form the electrolyte layer 36. Next, the positive electrode lead 31 is attached to the positive electrode current collector 33A, and the negative electrode lead 32 is attached to the negative electrode current collector 34A. Subsequently, the positive electrode 33 and the negative electrode 34 on which the electrolyte layer 36 is formed are laminated via a separator 35 to form a laminated body, and then the laminated body is wound in the longitudinal direction, and the protective tape 37 is attached to the outermost peripheral portion. The wound electrode body 30 is formed by bonding. After that, for example, the wound electrode body 30 is sandwiched between the exterior members 40, and the outer edge portions of the exterior members 40 are sealed and sealed by thermal fusion or the like. At that time, the adhesion film 41 is inserted between the positive electrode lead 31 and the negative electrode lead 32 and the exterior member 40. Thereby, the secondary battery shown in FIGS. 3 and 4 is completed.

  Further, this secondary battery may be manufactured as follows. First, the positive electrode 33 and the negative electrode 34 are prepared as described above, and after the positive electrode lead 31 and the negative electrode lead 32 are attached to the positive electrode 33 and the negative electrode 34, the positive electrode 33 and the negative electrode 34 are stacked via the separator 35 and wound. Rotate and adhere the protective tape 37 to the outermost periphery to form a wound body that is a precursor of the wound electrode body 30. Next, the wound body is sandwiched between the exterior members 40, and the outer peripheral edge portion excluding one side is heat-sealed to form a bag shape, and is stored inside the exterior member 40. Subsequently, an electrolyte composition including an electrolytic solution, a monomer that is a raw material of the polymer compound, a polymerization initiator, and other materials such as a polymerization inhibitor as necessary is prepared, and the interior of the exterior member 40 Then, the opening of the exterior member 40 is heat-sealed and sealed. Thereafter, heat is applied to polymerize the monomer to obtain a polymer compound, thereby forming a gel electrolyte layer 36, and assembling the secondary battery shown in FIGS.

  The operation and effect of the secondary battery are the same as those in the first to third embodiments described above.

  Further, specific embodiments of the present invention will be described in detail.

(Examples 1-1 to 1-28, Comparative examples 1-1 to 1-29)
The cylindrical secondary battery shown in FIGS. First, as the positive electrode active material, a material represented by LiCo _g Ni _h Mn _j M1 _k O ₂ X1 _n whose average composition is represented by the chemical formula 4 is prepared, and the composition is determined in Examples 1-1 to 1-28. Changes were made as shown in Table 1. Next, 91 parts by mass of the positive electrode active material, 6 parts by mass of artificial graphite as a conductive material, and 3 parts by mass of polyvinylidene fluoride as a binder are mixed and dispersed in N-methyl-2-pyrrolidone as a solvent. A positive electrode mixture slurry was obtained. Subsequently, the positive electrode mixture slurry was uniformly applied to both surfaces of a positive electrode current collector 21A made of an aluminum foil, dried, and compression-molded to form a positive electrode active material layer 21B, thereby producing the positive electrode 21. After that, an aluminum positive electrode lead 25 was attached to one end of the positive electrode current collector 21A.

  Moreover, the negative electrode 22 was produced by forming the negative electrode active material layer 22B which consists of silicon by the electron beam vapor deposition method in 22 A of negative electrode collectors which consist of copper foil. After that, a nickel negative electrode lead 26 was attached to one end of the negative electrode current collector 22A. The filling amount of the positive electrode active material and silicon was adjusted so that lithium metal was not deposited on the negative electrode 22 during charging.

Next, a separator 23 having a three-layer structure made of polypropylene-polyethylene-polypropylene is prepared, and the negative electrode 22, the separator 23, the positive electrode 21, and the separator 23 are laminated in this order and wound many times in a spiral shape to produce a wound electrode body 20. did. Subsequently, the wound electrode body 20 is sandwiched between the pair of insulating plates 12 and 13, the negative electrode lead 26 is welded to the battery can 11, and the positive electrode lead 25 is welded to the safety valve mechanism 15. The can 11 was stored inside. After that, an electrolytic solution was injected into the battery can 11 by a reduced pressure method. For the electrolyte, lithium hexafluorophosphate as an electrolyte salt in a solvent in which 10% by mass of difluoroethylene carbonate (DFEC), 40% by mass of ethylene carbonate (EC), and 50% by mass of dimethyl carbonate (DMC) were mixed. Was dissolved at a concentration of 1 mol / dm ³ . After injecting the electrolytic solution, the battery can 11 was caulked to fix the battery lid 14 and hermetically sealed to obtain secondary batteries of Examples 1-1 to 1-28.

As Comparative Example 1-1 for this example, a secondary battery was fabricated in the same manner as in this example, except that LiCoO ₂ was used as the positive electrode active material. Further, as Comparative Examples 1-2 to 1-29, secondary batteries were fabricated in the same manner as in this example, except that fluoroethylene carbonate (FEC) was used instead of difluoroethylene carbonate as a solvent. At that time, the same positive electrode active materials as those of Examples 1-1 to 1-28 were used as the positive electrode active materials of Comparative Examples 1-2 to 1-29.

For the fabricated secondary batteries of Examples 1-1 to 1-28 and Comparative Examples 1-1 to 1-29, the capacity recovery rate after high-temperature continuous charging was examined. Specifically, charging / discharging is repeated 10 cycles at 60 ° C. First, the discharge capacity at the 10th cycle is determined as the capacity before continuous charging, and then continuous charging is performed at 60 ° C. for 200 hours, followed by discharging at 60 ° C. The capacity after continuous charging was determined, and the ratio of the capacity after continuous charging to the capacity before continuous charging, that is, (capacity after continuous charging / capacity before continuous charging) × 100 was determined. The charging and discharging are performed under the same conditions except for continuous charging, and charging is performed at a constant current density of 1 mA / cm ² until the battery voltage reaches 4.2 V, and then the current density is set at 0.2 V at a constant voltage of 4.2 V. performed until a 02mA / cm ^2, discharge was performed until the battery voltage reached 2.5V at a constant current density of 1 mA / cm ^2. The continuous charging was performed until the battery voltage reached 4.2 V at a constant current density of 1 mA / cm ² until the total charging time reached 200 hours at a constant voltage of 4.2 V. The obtained results are shown in Tables 1 and 2.

As shown in Tables 1 and 2, according to Examples 1-1 to 1-25, Comparative Examples 1-2 to 1-26 in which fluoroethylene carbonate was added to the electrolytic solution, and LiCoO ₂ to the positive electrode active material. Compared to Comparative Example 1-1 used, the capacity recovery rate after high-temperature continuous charging could be improved. Moreover, also about Examples 1-26 to 1-28 which added M1 or X1 to the positive electrode active material, the outstanding characteristic was able to be obtained similarly to Example 1-12. That is, it was found that high temperature characteristics can be improved by using a positive electrode active material having an average composition represented by Chemical Formula 4 and using difluoroethylene carbonate in the electrolyte.

  Further, comparing Examples 1-1 to 1-24, as the nickel composition h is decreased and the manganese composition j is increased, the capacity recovery rate is improved within the range of h> j, and h <j. The tendency to decrease was seen. Furthermore, the highest characteristics were obtained in Example 1-12 in which the compositions g, h, and j of cobalt, nickel, and manganese were 1: 1: 1. That is, it is preferable to use a positive electrode active material in the range of h ≧ j in Chemical Formula 4, and it is more preferable to use a positive electrode active material of g: h: j = 1: 1: 1. .

(Examples 2-1 to 2-28, Comparative Examples 2-1 to 2-28)
In Examples 2-1 to 2-28, as shown in Table 3, except that the composition ratio of the solvent was 5% by mass of difluoroethylene carbonate, 45% by mass of ethylene carbonate, and 50% by mass of dimethyl carbonate, Others were made in the same manner as in Examples 1-1 to 1-28, and secondary batteries were made.

  As Comparative Examples 2-1 to 2-28 for this example, secondary batteries were fabricated in the same manner as in this example, except that fluoroethylene carbonate was used instead of difluoroethylene carbonate as the solvent. At that time, the same positive electrode active materials as those of Examples 2-1 to 2-28 were used as the positive electrode active materials of Comparative Examples 2-1 to 2-28, respectively.

  For the fabricated secondary batteries of Examples 2-1 to 2-28 and Comparative Examples 2-1 to 2-28, the capacity recovery rate after high-temperature continuous charging was also the same as in Examples 1-1 to 1-28. Examined. The results are shown in Tables 3 and 4.

As shown in Tables 3 and 4, according to Examples 2-1 to 2-28, compared with Comparative Examples 2-1 to 2-28 in which fluoroethylene carbonate was added to the electrolyte, The capacity recovery rate could be improved. Furthermore, from the results of Tables 1 to 4, it was possible to obtain a high capacity recovery rate after high-temperature continuous charging even when difluoroethylene carbonate was low in content (5% by mass) compared to fluoroethylene carbonate. For this reason, it was found that difluoroethylene carbonate can maintain high temperature characteristics even with a relatively small addition amount.

(Examples 3-1 to 3-6, Comparative examples 3-1 to 3-7)
A secondary battery was fabricated in the same manner as in Examples 1-1 to 1-28, except that the content of difluoroethylene carbonate or fluoroethylene carbonate in the positive electrode active material and the solvent was changed as shown in Table 5. did. In Examples 3-1 and 3-4, LiMn ₂ O ₄ having an average composition represented by Formula ₅ was used, and in Examples 3-2 and 3-5, LiFePO ₄ having an average composition represented by Formula 6 was used. In Examples 3-3 and 3-6, LiCo _0.33 Ni _0.33 Mn _0.33 O _{2 in} which the average composition used in Example 1-12 is represented by Chemical Formula 1 and LiMn in which the average composition is represented by Chemical Formula 5 are used. _A mixture of ₂ O ₄ and LiCo _0.33 Ni _0.33 Mn _0.33 O ₂ : LiMn ₂ O ₄ = 1: 2 was used. Moreover, in Examples 3-1 to 3-3, what used the content rate of difluoroethylene carbonate in a solvent as 10 mass% was used, and in Examples 3-4 to 3-6, the content rate of difluoroethylene carbonate in a solvent was set. What was 5 mass% was used.

As Comparative Examples 3-1 to 3-6 for this example, secondary batteries were fabricated in the same manner as in this example, except that fluoroethylene carbonate was used instead of difluoroethylene carbonate as the solvent. At that time, the same positive electrode active materials of Comparative Examples 3-1 to 3-6 as those of Examples 3-1 to 3-6 were used in correspondence with each other. Further, as Comparative Example 3-7, a secondary battery was prepared in the same manner as in this example, except that LiCoO ₂ was used as the positive electrode active material and a solvent having a difluoroethylene carbonate content of 10% by mass was used. Produced.

  For the fabricated secondary batteries of Examples 3-1 to 3-6 and Comparative Examples 3-1 to 3-7, the capacity recovery rate after high-temperature continuous charging was also the same as in Examples 1-1 to 1-28. Examined. The results are shown in Table 5 together with the results of Comparative Example 1-1.

As shown in Table 5, according to Examples 3-1 to 3-6, compared with Comparative Examples 3-1 to 3-6 in which fluoroethylene carbonate was added to the electrolytic solution, difluoroethylene carbonate at the same content rate. Those with the addition of can improve the capacity recovery after high-temperature continuous charging. In particular, comparison between Examples 3-4 to 3-6 and Comparative Examples 3-4 to 3-6 revealed that difluoroethylene carbonate can maintain high high temperature characteristics even with a relatively small addition amount. Moreover, compared with Comparative Examples 1-1 and 3-7 in which LiCoO ₂ was used as the positive electrode active material, the capacity recovery rate after high-temperature continuous charging could be greatly improved. That is, it was found that high temperature characteristics can be improved even when a positive electrode active material having an average composition represented by Chemical Formula 5 or Chemical Formula 6 is used and difluoroethylene carbonate is included in the electrolytic solution. Further, it was found that the same effect can be obtained even when a positive electrode active material whose average composition is represented by chemical formula 4, chemical formula 5 or chemical formula 6 is mixed and used.

(Examples 4-1 and 4-2, Comparative examples 4-1 to 4-5)
A secondary battery was fabricated in the same manner as in Examples 1-1 to 1-28, except that the composition ratio of the positive electrode active material and the solvent was as shown in Table 6. Moreover, also about Comparative Examples 4-1 to 4-5, it was set as the composition of the positive electrode active material and solvent shown in Table 6, and the secondary battery was produced similarly to the present Example.

Regarding the fabricated secondary batteries of Examples 4-1 and 4-2 and Comparative Examples 4-1 to 4-5, the capacity recovery rate after high-temperature storage in a charged state was examined. Specifically, after obtaining the capacity before storage at high temperature at room temperature, charge and store at 80 ° C. for 24 hours, discharge once, recharge, and then discharge to determine the capacity after storage at high temperature. The ratio of the capacity after high temperature storage to the capacity before storage, that is, (capacity after high temperature storage / capacity before storage) × 100 was determined. In charging and discharging, charging is performed at a constant current density of 1 mA / cm ² until the battery voltage reaches 4.2 V, and then at a constant voltage of 4.2 V until the current density reaches 0.02 mA / cm ^2. The discharge was performed at a constant current density of 500 mA / cm ² until the battery voltage reached 3V. The results obtained are shown in Table 6.

  As shown in Table 6, when a positive electrode active material having an average composition represented by Chemical Formula 4 is used and difluoroethylene carbonate is contained in the electrolyte, the state of charge is higher than that containing fluoroethylene carbonate after high temperature storage. It was found that a capacity recovery rate of

(Examples 5-1 to 5-4, Comparative Examples 5-1 to 5-4)
A secondary battery was fabricated in the same manner as in Example 1-12, except that the structure of the negative electrode 22 was changed. In Example 5-1, 90% by mass of silicon powder having an average particle diameter of 1 μm and 10% by mass of polyvinylidene fluoride as a binder were dispersed in N-methyl-2-pyrrolidone as a solvent, and from a copper foil The negative electrode current collector 22A was coated, dried, compression-molded, and then heat-treated to produce the negative electrode 22.

  In Example 5-2, tin-cobalt-indium-titanium alloy powder and carbon powder were mixed, and after synthesizing a CoSnC-containing material using a mechanochemical reaction, 80 parts by mass of this CoSnC-containing material powder, 11 parts by mass of graphite as a conductive material and 1 part by mass of acetylene black and 8 parts by mass of polyvinylidene fluoride as a binder are dispersed in N-methyl-2-pyrrolidone as a solvent, and a negative electrode collector made of copper foil The negative electrode 22 was produced by applying to the electric body 22A, drying and compression molding.

  In Example 5-3, the negative electrode 22 was produced by attaching a lithium metal foil to a copper foil. In Example 5-4, 92 parts by mass of artificial graphite powder and 8 parts by mass of polyvinylidene fluoride as a binder were dispersed in N-methyl-2-pyrrolidone as a solvent, and a negative electrode current collector made of copper foil The negative electrode 22 was produced by applying to the body 22A, drying and compression molding.

  As Comparative Examples 5-1 to 5-4 for this example, secondary batteries were fabricated in the same manner as in this example, except that fluoroethylene carbonate was used instead of difluoroethylene carbonate as the solvent. That is, the structure of the negative electrode was changed corresponding to each of Examples 5-1 to 5-4.

  For the fabricated secondary batteries of Examples 5-1 to 5-4 and Comparative Examples 5-1 to 5-4, the capacity recovery rate after high-temperature continuous charging was examined in the same manner as in Example 1-12. The results are shown in Table 7 together with the results of Example 1-12 and Comparative Example 1-13.

  As shown in Table 5, according to Examples 5-1 to 5-4, compared with Comparative Examples 5-1 to 5-4, all can improve the capacity recovery rate after high-temperature continuous charging. It was. That is, it was found that the same effect can be obtained even when the negative electrode 22 having another configuration is used.

  Although the present invention has been described with reference to the embodiments and examples, the present invention is not limited to the embodiments and examples, and various modifications can be made. For example, in the above-described embodiments and examples, the case where an electrolytic solution is used as the electrolyte is described. In the above-described embodiment, the case where a gel electrolyte in which the electrolytic solution is held in a polymer compound is used is also described. Other electrolytes may be used. Other electrolytes include, for example, a mixture of an ion conductive inorganic compound such as ion conductive ceramics, ion conductive glass or ionic crystal and an electrolytic solution, or a mixture of another inorganic compound and an electrolytic solution. Or a mixture of these inorganic compounds and a gel electrolyte.

  In the above embodiment or example, a cylindrical or laminated film type secondary battery has been specifically described, but the present invention has other shapes such as a coin type, a button type, or a square type. The present invention can be similarly applied to a secondary battery or a secondary battery having another structure such as a laminated structure. Further, the present invention is not limited to the secondary battery but can be similarly applied to other batteries such as a primary battery.

It is sectional drawing showing the structure of the secondary battery which concerns on the 1st Embodiment of this invention. It is sectional drawing which expands and represents a part of winding electrode body shown in FIG. It is a disassembled perspective view showing the structure of the secondary battery which concerns on the 4th Embodiment of this invention. It is sectional drawing showing the structure along the II line of the winding electrode body shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Battery can, 12, 13 ... Insulation board, 14 ... Battery cover, 15 ... Safety valve mechanism, 15A ... Disc board, 16 ... Heat sensitive resistance element, 17 ... Gasket, 20, 30 ... Winding electrode body, 21, 33 ... Positive electrode, 21A, 33A ... Positive electrode current collector, 21B, 33B ... Positive electrode active material layer, 22, 34 ... Negative electrode, 22A, 34A ... Negative electrode current collector, 22B, 34B ... Negative electrode active material layer, 23, 35 ... Separator , 24 ... Center pin, 25, 31 ... Positive electrode lead, 26, 32 ... Negative electrode lead, 36 ... Electrolyte layer, 37 ... Protective tape, 40 ... Exterior member, 41 ... Adhesion film.

Claims (5)

A battery comprising an electrolyte solution together with a positive electrode and a negative electrode,
The positive electrode contains at least one positive electrode active material having an average composition represented by chemical formula 1, chemical formula 2 or chemical formula 3,
The battery is characterized in that the electrolytic solution contains difluoroethylene carbonate.
(Chemical formula 1)
Li _f Co _g Ni _h Mn _j M1 _k O _(2-m) X1 _n
(In the formula, M1 is magnesium (Mg), aluminum (Al), boron (B), titanium (Ti), vanadium (V), chromium (Cr), iron (Fe), copper (Cu), zinc (Zn ), Zirconium (Zr), molybdenum (Mo), tin (Sn), calcium (Ca), strontium (Sr) and tungsten (W), and X1 is fluorine (F), At least one member selected from the group consisting of chlorine (Cl) and bromine (Br), where f, g, h, j, k, m, and n are 0.8 ≦ f ≦ 1.2 and 0 ≦ g <. 1, 0 <h ≦ 1, 0 ≦ j <1, 0 ≦ k ≦ 0.1, g + h + j + k = 1, −0.1 ≦ m ≦ 0.2, 0 ≦ n ≦ 0.1 is there.)
(Chemical formula 2)
Li _v Mn _2-w M2 _w O _x X2 _y
(Wherein M2 is selected from the group consisting of cobalt (Co), nickel (Ni), magnesium, aluminum, boron, titanium, vanadium, chromium, iron, copper, zinc, molybdenum, tin, calcium, strontium and tungsten). X2 is at least one selected from the group consisting of fluorine, chlorine and bromine, and v, w, x and y are 0.9 ≦ v ≦ 1.1, 0 ≦ w ≦ 0. (6, 3.7 ≦ x ≦ 4.1, 0 ≦ y ≦ 0.1)
(Chemical formula 3)
Li _z M3PO ₄
(Wherein M3 is a group consisting of cobalt, manganese (Mn), iron, nickel, magnesium, aluminum, boron, titanium, vanadium, niobium (Nb), copper, zinc, molybdenum, calcium, strontium, tungsten and zirconium. (Z is a value in the range of 0.9 ≦ z ≦ 1.1.)   The battery according to claim 1, wherein the positive electrode contains a positive electrode active material satisfying h ≧ j in Chemical Formula 1.   2. The battery according to claim 1, wherein the negative electrode contains at least one selected from the group consisting of tin, silicon (Si), carbon (C), and lithium metal as a negative electrode active material.   The battery according to claim 1, wherein the negative electrode active material is alloyed at least at a part of the interface with the negative electrode current collector. 5. The battery according to claim 4, wherein at least a part of the negative electrode is formed by one or more methods selected from the group consisting of a vapor phase method, a liquid phase method, and a firing method.

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