JP2006216450A - Battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a battery of which battery characteristics such as cycle characteristics can be improved. <P>SOLUTION: A negative electrode active material containing Sn or Si as a constituting element is contained in the negative electrode 22. An electrolytic solution is impregnated into a separator 23. In the electrolytic solution, 4-fluoro-1,3-dioxolane-2-on is contained. The amount of fluoride ions in the electrolytic solution is 10 wtppm or more and 500 wtppm or less, and the moisture content is 10 wtppm or less. By this, chemical stability of the electrolytic solution is improved, and according to charging and discharging, new coatings are sequentially formed on the surface of the negative electrode 22 by the fluoride ions contained in the electrolytic solution. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a battery using a negative electrode material capable of occluding and releasing an electrode reactant and including at least one member selected from the group consisting of metal elements and metalloid elements as constituent elements.

  In recent years, many portable electronic devices such as notebook portable computers, cellular phones, or camera-integrated VTRs (video tape recorders) have appeared, and their size and weight 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 that can obtain a high energy density, for example, a lithium ion secondary battery is known.

In general, a lithium compound that generates lithium ions is added to the electrolytic solution of the lithium ion secondary battery. A typical lithium compound is, for example, lithium hexafluorophosphate (LiPF ₆ ). Most of lithium compounds including lithium hexafluorophosphate react with water to generate fluorine ions ( F ⁻ ) is generated (see, for example, Patent Document 1). And the fluorine ion produced | generated by reaction with water is said to be one of the causes of deteriorating a battery and shortening battery life (for example, refer patent document 2).

In addition, the negative electrode of the lithium ion secondary battery includes a negative electrode active material such as a graphite material using a lithium intercalation reaction between graphite layers, or a carbonaceous material that applies lithium occlusion / release to the pores. Substance is used. However, the negative electrode capacity due to intercalation has an upper limit as defined by the composition C ₆ Li of the first stage graphite intercalation compound. In addition, it is industrially difficult to control the fine pore structure of the carbonaceous material and causes a decrease in the specific gravity of the carbonaceous material, thereby improving the negative electrode capacity per unit volume and thus the battery capacity per unit volume. Is difficult.

Therefore, in order to cope with the longer usage time of future electronic devices and the higher energy density of the power source, development of a negative electrode material capable of obtaining a higher capacity is desired. As such negative electrode materials, materials that apply the electrochemical and reversible generation and decomposition of certain lithium alloys have been extensively studied, and lithium-aluminum alloys or silicon alloys have been reported. (For example, refer to Patent Document 3).
Japanese Patent Laid-Open No. 2002-216741 JP 2002-198088 A U.S. Pat. No. 4,950,566

  However, these alloy materials are greatly expanded and contracted with charge and discharge, and are pulverized, so that there is a problem that the cycle characteristics are deteriorated. In order to solve this problem, the composition of the electrolytic solution was examined, and it was found that the cycle characteristics can be dramatically improved by adding 4-fluoro-1,3-dioxolan-2-one. Therefore, in order to further improve the characteristics, an experiment was performed with the fluorine ion amount and the water content in the electrolytic solution being reduced as much as possible, but the characteristics were not improved so much.

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

  A battery according to the present invention includes an electrolyte solution together with a positive electrode and a negative electrode, the negative electrode is capable of occluding and releasing an electrode reactant, and at least one of the group consisting of metal elements and metalloid elements as constituent elements. A negative electrode material containing one kind, the electrolytic solution contains 4-fluoro-1,3-dioxolan-2-one, and the fluorine ion content is within a range of 10 mass ppm to 500 mass ppm, The water content is within a range of 10 mass ppm or less.

  According to the battery of the present invention, the electrolyte contains 4-fluoro-1,3-dioxolan-2-one, and the water content in the electrolyte is 10 mass ppm or less. Chemical stability can be improved. Moreover, since content of the fluorine ion in electrolyte solution was made into the range of 10 mass ppm or more and 500 mass ppm or less, an appropriate film can be formed on the surface of a negative electrode. Therefore, it is possible to occlude and release electrode reactants, and to improve battery characteristics such as cycle characteristics even when a negative electrode material containing at least one of the group consisting of metal elements and metalloid elements as a constituent element is used. Can do.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following examples, the case where lithium is used as the electrode reactant will be described.

  FIG. 1 shows a cross-sectional configuration of a secondary battery according to an embodiment of the present invention. 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 (Fe) 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 (Al) 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 (Ni) 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 21B includes, for example, one or more of positive electrode materials capable of inserting and extracting lithium as a positive electrode active material, and a conductive material such as a carbon material and polyfluoride as necessary. A binder such as vinylidene may be included. The positive electrode material capable of inserting and extracting lithium does not contain lithium such as titanium sulfide (TiS ₂ ), molybdenum sulfide (MoS ₂ ), niobium selenide (NbSe ₂ ), or vanadium oxide (V ₂ O ₅ ). Examples include chalcogenides and lithium-containing compounds containing lithium.

Among these, lithium-containing compounds are preferable because some compounds can obtain a high voltage and a high energy density. Examples of such a lithium-containing compound include a composite oxide containing lithium and a transition metal element, or a phosphate compound containing lithium and a transition metal element. In particular, cobalt (Co), nickel and manganese (Mn Among these, those containing at least one of them are preferred. This is because a higher voltage can be obtained. The chemical formula is represented by, for example, Li _x MIO ₂ or Li _y MIIPO ₄ . In the formula, MI and MII represent one or more transition metal elements. The values of x and y vary depending on the charge / discharge state of the battery, and are generally 0.05 ≦ x ≦ 1.10 and 0.05 ≦ y ≦ 1.10.

Specific examples of the composite oxide containing lithium and a transition metal element include lithium cobalt composite oxide (Li _x CoO ₂ ), lithium nickel composite oxide (Li _x NiO ₂ ), and lithium nickel cobalt composite oxide (Li _x Ni _1-z Co _z O ₂ (z <1)) or lithium manganese composite oxide (LiMn ₂ O ₄ ) having a spinel structure. Among these, a composite oxide containing nickel is preferable. This is because a high capacity can be obtained and excellent cycle characteristics can also be obtained. Specific examples of the phosphate compound containing lithium and a transition metal element include, for example, a lithium iron phosphate compound (LiFePO ₄ ) or a lithium iron manganese phosphate compound (LiFe _1-v Mn _v PO ₄ (v <1)). Can be mentioned.

  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 (Cu) foil, a nickel foil, or a stainless steel foil.

  The negative electrode active material layer 22B is, for example, any one of negative electrode materials capable of inserting and extracting lithium as a negative electrode active material and including at least one of the group consisting of a metal element and a metalloid element as a constituent element. 1 type or 2 types or more are included. Specific examples of such a negative electrode material include a metal element or a metalloid element, an alloy, a compound, or a material having at least a part of one or two or more phases thereof. In the present invention, 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 such metal elements or metalloid elements include magnesium (Mg), boron (B), aluminum, gallium (Ga), indium (In), germanium (Ge), and lead (Pb) capable of forming an alloy with lithium. , Bismuth (Bi), cadmium (Cd), silver (Ag), zinc (Zn), hafnium (Hf), zirconium (Zr), yttrium (Y), palladium (Pd) or platinum (Pt). Among these, tin or silicon is preferable, and silicon is particularly preferable. This is because the ability to occlude and release lithium is large, and a high energy density can be obtained.

For example, silicon alloys or compounds include SiB ₄ , SiB ₆ , Mg ₂ Si, Ni ₂ Si, TiSi ₂ , MoSi ₂ , CoSi ₂ , NiSi ₂ , CaSi ₂ , CrSi ₂ , Cu ₅ Si, FeSi ₂ , MnSi. ₂ , NbSi ₂ , TaSi ₂ , VSi ₂ , WSi ₂ , ZnSi ₂ , SiC, Si ₃ N ₄ , Si ₂ N ₂ O, SiO _u (0 <u ≦ 2), SnSiO ₃ , LiSiO and the like.

  The negative electrode active material layer 22b may be formed by a vapor phase method, a liquid phase method, or a baking method, or may be formed by coating. 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.

  In the case of coating, in addition to the negative electrode active material, other materials such as a binder such as polyvinylidene fluoride and a conductive agent may be included. The same applies to the case of the firing method.

  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 a solvent and an electrolytic solution dissolved in the solvent. The solvent contains 4-fluoro-1,3-dioxolan-2-one shown in Chemical formula 1. This is because cycle characteristics can be improved when the above-described materials are used for the negative electrode 22. The solvent may be composed only of 4-fluoro-1,3-dioxolan-2-one, but may be used by mixing one or more other solvents. This is because various properties such as ion conductivity can be improved. In that case, the content of 4-fluoro-1,3-dioxolan-2-one in the electrolytic solution is preferably 5% by mass or more. This is because if the content is small, the cycle characteristics cannot be sufficiently improved.

  Examples of other solvents include ethylene carbonate, propylene carbonate, butylene carbonate, vinylene carbonate, γ-butyrolactone, γ-valerolactone, 1,2-dimethoxyethane, 1,2-diethoxyethane, tetrahydrofuran, and 2-methyltetrahydrofuran. 1,3-dioxolane, 4-methyl-1,3-dioxolane, acetate ester, butyrate ester, propionate ester, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, acetonitrile, glutaronitrile, adiponitrile methoxyacetonitrile, etc. Non-aqueous solvents are mentioned.

  Among them, it is preferable to use 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 higher ionic conductivity can be obtained.

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

The content of fluorine ions (F ⁻ ) in the electrolytic solution is preferably in the range of 10 mass ppm to 500 ppm, and the water content is preferably in the range of 10 mass ppm or less. When these contents are large, the chemical stability of the electrolytic solution is lowered and the cycle characteristics are deteriorated. However, when the negative electrode material as described above is used for the negative electrode 22, some fluorine ions are included. This is because a new coating can be formed on the surface of the negative electrode 22 along with charge and discharge, and cycle characteristics can be improved. In particular, in the present embodiment, since 4-fluoro-1,3-dioxolan-2-one is contained in the electrolytic solution, even if the amount of water in the electrolytic solution increases after manufacturing the battery, it is consumed by hydrolysis. In addition, it is possible to generate fluorine ions by this hydrolysis and replenish the fluorine ions consumed for film formation, so that the cycle characteristics can be further improved.

  In addition, content of a fluorine ion can be measured by the titration method described in the solid state ionics (solid state ionics) ten148 (2002) 391, for example. Specifically, for example, 10 ml of acetone is added as a buffer solvent to 100 μl of an electrolytic solution, 3 drops of bromophenol blue / acetone solution indicator is added, and an aqueous tetra-n-butylammonium hydroxide / methanol solution having a concentration of 0.01% by mass is added. Titration is performed as a base titration reagent. The moisture content can be measured by, for example, a Karl Fischer moisture meter.

  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 a positive electrode active material powder, a conductive agent, and a binder to prepare a positive electrode mixture, and then using the positive electrode mixture in a solvent such as N-methyl-2-pyrrolidone. The positive electrode mixture slurry is dispersed to form a positive electrode mixture slurry, and the positive electrode mixture slurry is applied to the positive electrode current collector 21A, dried, and compression molded.

  Further, for example, the negative electrode active material layer 22B is formed on the negative electrode current collector 22A to produce the negative electrode 22. The negative electrode active material layer 22B may be formed by, for example, any one of a vapor phase method, a liquid phase method, a baking method, and coating, or a combination of two or more thereof.

  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 ( CVD (Chemical Vapor Deposition) method, plasma chemical vapor deposition method or thermal spraying method can be used. As the liquid phase method, a known method such as electroplating or electroless plating can be used. As for the firing method, a known method can be used. For example, an atmosphere firing method, a reaction firing method, or a hot press firing method can be used. In the case of application, it can be formed in the same manner as the positive electrode 21.

  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, the electrolytic solution is injected into the battery can 11 and impregnated in the separator 23. At that time, the content of fluorine ions and the amount of water in the electrolytic solution are adjusted. After that, the battery lid 14, the safety valve mechanism 15, and the heat sensitive resistance element 16 are fixed to the opening end of the battery can 11 by caulking through a gasket 17. Thereby, the secondary battery shown in FIG. 1 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. At this time, if the electrolyte solution contains excessive fluorine ions and moisture, the battery deteriorates. In this embodiment, the fluorine ion content is 500 ppm by mass or less, and the moisture content is 10%. Since it is set as the mass ppm or less, deterioration of a battery is suppressed. In addition, since the fluorine ion content is 10 mass ppm or more, a new coating is sequentially formed on the surface of the negative electrode 22 with charge and discharge, and the decomposition reaction of the electrolytic solution is suppressed.

  Thus, according to the present embodiment, the electrolytic solution contains 4-fluoro-1,3-dioxolan-2-one, the content of fluorine ions in the electrolytic solution is 500 ppm by mass or less, and the content of moisture is Since it was made into 10 mass ppm or less, the chemical stability of electrolyte solution can be improved. In addition, since the content of fluorine ions in the electrolytic solution is set to 10 mass ppm or more, an appropriate film can be formed on the surface of the negative electrode 22. Therefore, even if a negative electrode material that can occlude and release electrode reactants and includes at least one member selected from the group consisting of metal elements and metalloid elements as a constituent element is used for the negative electrode 22, battery characteristics such as cycle characteristics can be obtained. Can be improved.

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

(Examples 1-1 to 1-3)
A coin-type secondary battery as shown in FIG. 3 was produced. In the secondary battery, a positive electrode 31 and a negative electrode 32 are stacked via a separator 33 and sealed between an outer can 34 and an outer cup 35.

First, lithium carbonate (Li ₂ CO ₃ ) and cobalt carbonate (CoCO ₃ ) are mixed at a molar ratio of Li ₂ CO ₃ : CoCO ₃ = 0.5: 1, and this mixture is mixed at 900 ° C. in air. lithium cobalt composite oxides by firing five hours a positive electrode active material (LiCoO ₂₎ was synthesized. Next, 94 parts by mass of this lithium cobalt composite oxide powder, 3 parts by mass of graphite as a conductive agent, and 3 parts by mass of polyvinylidene fluoride as a binder were prepared, and then a positive electrode mixture was prepared. A positive electrode mixture slurry was prepared by dispersing in some N-methyl-2-pyrrolidone. Subsequently, the positive electrode mixture slurry was applied to both surfaces of a positive electrode current collector 31A made of an aluminum foil having a thickness of 20 μm, dried, and then compression molded to form a positive electrode active material layer 31B. After that, a positive electrode 31 was produced by punching into a pellet having a diameter of 15 mm.

  Moreover, after preparing a silicon powder having an average particle diameter of 1 μm as a negative electrode active material, 90 parts by mass of this silicon powder and 10 parts by mass of polyvinylidene fluoride as a binder were prepared, and then a negative electrode mixture was prepared. A negative electrode mixture slurry was prepared by dispersing in N-methyl-2-pyrrolidone as a solvent. Next, the negative electrode current collector 32A made of a copper foil having a thickness of 18 μm was coated on both surfaces, dried, and then compression molded to form the negative electrode active material layer 32B. After that, the negative electrode 32 was produced by punching into a 15 mm diameter pellet.

  Subsequently, the produced positive electrode 31 and negative electrode 32 are laminated on an outer can 34 via a separator 33 made of a microporous polyethylene film, and an electrolytic solution is injected from above to cover the outer cup 35 and sealed. did. For the electrolyte, 1 mol / liter of lithium hexafluorophosphate as an electrolyte salt was added to a solvent in which 4-fluoro-1,3-dioxolan-2-one (FEC) and diethyl carbonate (DEC) were mixed at an equal mass ratio. Those dissolved at a concentration of kg were used.

  At that time, the amount of fluorine ions and the amount of water in the electrolytic solution are adjusted by adjusting the fluorine ions contained as impurities in 4-fluoro-1,3-dioxolan-2-one and the moisture contained as impurities in the electrolytic solution, The change was made as shown in Table 1 in Examples 1-1 to 1-3. A fluorine ion amount and a water content of 10 ppm by mass or less were obtained by removing a certain amount of fluorine ions and water by purification and then adsorbing and removing them on a molecular sieve. The amount of fluorine ions in the electrolytic solution was measured by the titration method described above, and the amount of water was measured by a Karl Fischer moisture meter (manufactured by Hiranuma Sangyo Co., Ltd.).

  In addition, as Comparative Examples 1-1 to 1-5 with respect to Examples 1-1 to 1-3, except that the amount of fluorine ions and the amount of water in the electrolytic solution were changed as shown in Table 1, the others were implemented. Secondary batteries were fabricated in the same manner as in Examples 1-1 to 1-3. Further, as Comparative Examples 1-6 and 1-7 for Examples 1-1 to 1-3, 1,3-dioxolan-2-one (carbonic acid carbonate) was used instead of 4-fluoro-1,3-dioxolan-2-one. Except for changing the amount of fluorine ions and the amount of water in the electrolytic solution as shown in Table 1, using ethylene: EC), the secondary battery was prepared in the same manner as in Examples 1-1 to 1-3. Produced.

The fabricated secondary batteries of Examples 1-1 to 1-3 and Comparative Examples 1-1 to 1-7 were subjected to a charge / discharge test to examine the initial charge / discharge efficiency and cycle characteristics. At that time, charging was performed at a constant current density of 1 mA / cm ² until the battery voltage reached 4.2 V, and then at a constant voltage of 4.2 V until the current density reached 0.02 mA / cm ^2. The test was performed at a constant current density of 1 mA / cm ² until the battery voltage reached 2.5V. The initial charge / discharge efficiency was determined from (discharge capacity at the first cycle / charge capacity at the first cycle) × 100. The cycle characteristics were determined from the ratio of the discharge capacity at the 100th cycle to the discharge capacity at the first cycle, that is, (discharge capacity at the 100th cycle / discharge capacity at the first cycle) × 100. The obtained results are shown in Table 1.

  As shown in Table 1, according to Examples 1-1 to 1-3, Comparative Examples 1-1 and 1-2 having a moisture content of more than 10 mass ppm, and a fluorine ion content of more than 500 ppm by mass. Comparative Examples 1-3, 1-4, Comparative Example 1-5 having a fluorine ion content of less than 10 ppm by mass, and Comparative Examples 1-6 without using 4-fluoro-1,3-dioxolan-2-one Compared with 1-7, the initial charge / discharge efficiency and cycle characteristics could be improved.

  That is, while 4-fluoro-1,3-dioxolan-2-one is used for the electrolytic solution, the fluorine ion content in the electrolytic solution is 10 mass ppm or more and 500 mass ppm or less, and the moisture content is 10 mass ppm or less. It was found that the initial charge / discharge efficiency and cycle characteristics can be improved by doing so.

(Examples 2-1 to 2-3)
Except that the negative electrode active material layer 32B made of silicon was formed by a sputtering method and the amount of fluorine ions and the amount of water in the electrolytic solution were changed as shown in Table 2, the other examples 1-1 to 1-3 were made. A secondary battery was fabricated in the same manner as described above.

  In addition, as Comparative Examples 2-1 to 2-5 with respect to Examples 2-1 to 2-3, except that the amount of fluorine ions and the amount of water in the electrolytic solution were changed as shown in Table 2, the others were implemented. Secondary batteries were fabricated in the same manner as in Examples 2-1 to 2-3. Further, as Comparative Examples 2-6 and 2-7 for Examples 2-1 to 2-3, 1,3-dioxolan-2-one (carbonic acid carbonate) was used instead of 4-fluoro-1,3-dioxolan-2-one. Except for changing the amount of fluorine ions and the amount of water in the electrolyte solution as shown in Table 2, using the ethylene: EC), the secondary battery was prepared in the same manner as in Examples 2-1 to 2-3. Produced.

  For the fabricated secondary batteries of Examples 2-1 to 2-3 and Comparative Examples 2-1 to 2-7, a charge / discharge test was performed in the same manner as in Examples 1-1 to 1-3, and the initial charge / discharge was performed. Efficiency and cycle characteristics were investigated. The obtained results are shown in Table 2.

  As shown in Table 2, according to Examples 2-1 to 2-3, the initial charge and discharge efficiency and the cycle were higher than those of Comparative Examples 1-1 to 7 as in Examples 1-1 to 1-3. The characteristics could be improved. That is, it has been found that the same result can be obtained even if the negative electrode is formed by another manufacturing method.

  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 embodiments and examples, the case where the electrolytic solution is used as it is has been described. However, the electrolytic solution may be held in a polymer compound or an ion conductive inorganic compound.

  Further, in the above embodiments and examples, a cylindrical or coin-type secondary battery has been specifically described, but the present invention uses a card-type, button-type, square-type, or film-type exterior member. The present invention can be similarly applied to secondary batteries having other shapes, or secondary batteries having other structures such as a stacked structure. Further, the present invention is not limited to the secondary battery, and can be similarly applied to other batteries such as a primary battery.

  Further, in the above embodiments and examples, a battery using lithium as an electrode reactant has been described. However, another alkali metal such as sodium (Na) or potassium (K), or an alkali such as magnesium or calcium (Ca) is used. The present invention can also be applied to the case of using an earth metal or another light metal such as aluminum. At that time, the negative electrode active material described in the above embodiment, for example, a material containing tin or silicon as a constituent element can be used in the same manner for the negative electrode.

It is sectional drawing showing the structure of the secondary battery which concerns on one embodiment of this invention. It is sectional drawing which expands and represents a part of winding electrode body in the secondary battery shown in FIG. It is sectional drawing showing the structure of the secondary battery produced in the Example of this invention.

Explanation of symbols

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

Claims (4)

A battery comprising an electrolyte solution together with a positive electrode and a negative electrode,
The negative electrode is capable of occluding and releasing an electrode reactant, and contains a negative electrode material including at least one member selected from the group consisting of metal elements and metalloid elements as constituent elements,
The electrolytic solution contains 4-fluoro-1,3-dioxolan-2-one, and the fluorine ion content is within a range of 10 mass ppm to 500 mass ppm, and the water content is 10 mass ppm or less. A battery characterized by being in the range of.   The battery according to claim 1, wherein the negative electrode contains a negative electrode material containing at least one of tin (Sn) and silicon (Si) as a constituent element.   The negative electrode has a negative electrode current collector and a negative electrode active material layer formed on the negative electrode current collector by at least one method selected from the group consisting of a gas phase method, a liquid phase method, and a firing method. The battery according to claim 1. The battery according to claim 1, wherein the positive electrode contains a composite oxide containing lithium (Li) and cobalt (Co).

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