JP2011124052A - Nonaqueous electrolyte secondary battery and method for charging the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte secondary battery having an electrode formed by using a material containing tin and capable of minimizing the reduction of capacity accompanying the charging/discharging cycle; and a method for charging the same. <P>SOLUTION: The nonaqueous electrolyte secondary battery is one having an electrode formed by using metal tin, and the potential of the electrode in charging is 0.2 V or higher on an Li/Li<SP>+</SP>basis. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention generally relates to a non-aqueous electrolyte secondary battery and a charging method thereof, and more particularly to a non-aqueous electrolyte secondary battery using tin (Sn) as an electrode and a charging method thereof.

  With the expansion of the market for portable electronic devices such as mobile phones, notebook computers, and digital cameras, secondary batteries with high energy density and long life are expected as cordless power sources for these electronic devices. In order to meet such demands, secondary batteries have been developed that use an alkali metal ion such as lithium ion as a charge carrier and use an electrochemical reaction associated with charge exchange. Among them, lithium ion secondary batteries having a large energy density are widely used.

  In the above lithium ion secondary battery, a lithium-containing transition metal oxide such as lithium cobaltate or lithium manganate is used as the positive electrode active material. In addition, a carbon material capable of inserting and extracting lithium ions is used as the negative electrode active material.

  By the way, as the functions of portable electronic devices increase, the power consumption thereof has increased remarkably. In order to cope with this increase in power consumption, a large-capacity lithium ion secondary battery has become necessary. However, as long as the carbon material is used as the negative electrode active material as described above, there is a limit to increasing the capacity of the lithium ion secondary battery.

  Therefore, tin (Sn) or a tin alloy having a theoretical energy density about 2.7 times that of carbon has been studied as a negative electrode active material.

  For example, in Japanese Patent Application Laid-Open No. 2008-41347 (hereinafter referred to as Patent Document 1), Sn plating is performed on the surface of a negative electrode current collector made of Cu foil or Cu alloy foil, and then predetermined heat treatment is performed to perform Sn plating. A method for producing a negative electrode for a lithium ion secondary battery by forming a Cu—Sn alloy layer by forming a Cu—Sn alloy has been proposed.

JP 2008-41347 A

  In the lithium ion secondary battery using the Cu—Sn alloy layer produced in Patent Document 1 as a negative electrode, a charge / discharge test is performed in the range of 0.01 to 1V. However, there is a problem in that the capacity reduction associated with the charge / discharge cycle becomes large.

  Accordingly, an object of the present invention is a nonaqueous electrolyte secondary battery using a material containing tin (Sn) as an electrode, and a nonaqueous electrolyte secondary battery capable of reducing a decrease in capacity caused by a charge / discharge cycle and its It is to provide a charging method.

The present inventor has intensively studied to solve the problems of the prior art. As a result, when the inventor uses an electrode made of a material containing Sn, the potential of the electrode is less than ⁰ to 0.2 V on the basis of Li / Li ⁺ , and Sn peeling and embrittlement occur rapidly. Thus, it was found that by repeating charge and discharge at a potential of 0.2 V or higher, Sn peeling and embrittlement can be suppressed, and the capacity drop due to the charge and discharge cycle can be reduced. Based on this knowledge, the nonaqueous electrolyte secondary battery according to the present invention has the following characteristics.

The nonaqueous electrolyte secondary battery according to the present invention is a nonaqueous electrolyte secondary battery using metallic tin as an electrode, and the potential of the electrode at the time of charging is 0.2 V or more on the basis of Li / Li ⁺ .

The nonaqueous electrolyte secondary battery according to the present invention is a nonaqueous electrolyte secondary battery using a lithium-containing substance as a positive electrode and metal tin as a negative electrode, and the potential of the negative electrode during charging is Li / Li ^+. The reference voltage is 0.2 V or higher.

  In the nonaqueous electrolyte secondary battery of the present invention, since the potential at the time of charging is 0.2 V or more, even if charging and discharging are repeated, Sn peeling and embrittlement can be suppressed. Thereby, the capacity | capacitance fall by a charging / discharging cycle can be made small.

  In the nonaqueous electrolyte secondary battery of the present invention, it is preferable to use a lithium transition metal composite oxide for the positive electrode.

In the above case, the lithium transition metal composite oxide has the composition formula Li _{1 + α} Ni _x Mn _y Co _z Me _β O ₂ (where α, β, x, y, and z are −1 <α ≦ 0.5, 0 ≦ β <0.3, 0 <x <1, 0 <y <1, 0 <z <1, x + y + z = 1, Me is a metal element other than Ni, Mn, and Co). It is preferable that it is the material which has.

  In the above case, the battery voltage during charging is preferably 4.1 V or less.

  In the nonaqueous electrolyte secondary battery of the present invention, the negative electrode is preferably metallic tin formed on a metal foil that is not alloyed with lithium.

In the above case, the negative electrode is preferably metallic tin formed on a copper foil and having a density of 6 g / cm ³ or more.

A non-aqueous electrolyte secondary battery charging method according to the present invention is a non-aqueous electrolyte secondary battery charging method using a lithium-containing substance as a positive electrode and metallic tin as a negative electrode. It is 0.2 V or more on the basis of Li / Li ⁺ .

In the method for charging a non-aqueous electrolyte secondary battery of the present invention, it is preferable to use a lithium transition metal composite oxide for the positive electrode. Note that the lithium transition metal composite oxide has the composition formula Li _{1 + α} Ni _x Mn _y Co _z Me _β O ₂ (where α, β, x, y, and z are −1 <α ≦ 0.5, 0 ≦ β <0. .3, 0 <x <1, 0 <y <1, 0 <z <1, x + y + z = 1, and Me is a metal element other than Ni, Mn, and Co) When is used, it is preferable that the battery voltage during charging is 4.1 V or less.

  ADVANTAGE OF THE INVENTION According to this invention, the capacity | capacitance fall accompanying a charging / discharging cycle can be made small in the nonaqueous electrolyte secondary battery using the material containing Sn for an electrode.

It is a figure which shows the coin type non-aqueous electrolyte secondary battery as one embodiment of this invention, and the coin type non-aqueous electrolyte secondary battery produced in Examples 1-5 and Comparative Example 1 of this invention. It is a figure which shows the change of a charge capacity and a discharge capacity as a result of the charging / discharging cycle test of the coin-type nonaqueous electrolyte secondary battery produced by Examples 1-2 of this invention, and the comparative example 1. FIG. It is a figure which shows the change of discharge capacity as a result of the charging / discharging cycle test of the coin-type nonaqueous electrolyte secondary battery produced in Examples 3-5 of this invention.

The electrode (negative electrode) used in the nonaqueous electrolyte secondary battery of the present invention is preferably a tin metal film as an example of metal tin formed on a metal foil that is not alloyed with lithium. In this case, examples of the metal foil that is not alloyed with lithium include copper (Cu), stainless steel, titanium (Ti), molybdenum (Mo), nickel (Ni), and iron (Fe). When a copper foil is used as the metal foil that is not alloyed with lithium, the density of the tin metal film is preferably 6 g / cm ³ or more.

In the nonaqueous electrolyte secondary battery of the present invention, the potential of the electrode (negative electrode) during charging is 0.2 V or more on the basis of Li / Li ⁺ . For this reason, even if charging / discharging is repeated, Sn peeling and embrittlement can be suppressed. Thereby, the capacity | capacitance fall by a charging / discharging cycle can be made small.

Furthermore, in the non-aqueous electrolyte secondary battery of the present invention, it is preferable to use a substance containing lithium for the positive electrode and metal tin for the negative electrode. Moreover, it is preferable to use a lithium transition metal complex oxide for the positive electrode. Further, the lithium transition metal composite oxide has the composition formula Li _{1 + α} Ni _x Mn _y Co _z Me _β O ₂ (where α, β, x, y, and z are −1 <α ≦ 0.5, 0 ≦ β <0. .3, 0 <x <1, 0 <y <1, 0 <z <1, x + y + z = 1, and Me is a metal element other than Ni, Mn, and Co) When is used, the battery voltage is preferably 4.1 V or less. In this case, even if charge and discharge are repeated, it is possible to suppress Sn peeling and embrittlement, and to further suppress deterioration of the positive electrode. Thereby, the capacity | capacitance fall by a charging / discharging cycle can be made small.

  Next, an example of a method for producing a nonaqueous electrolyte secondary battery when the metal tin of the present invention is used for a negative electrode will be described in detail below.

  First, a negative electrode is formed. For example, a negative electrode is formed by forming a tin plating film on a copper foil.

  Next, a positive electrode is formed. For example, a positive electrode active material is mixed with a conductive additive and a binder, an organic solvent or water is added to form a positive electrode active material slurry, and the positive electrode active material slurry is coated on the electrode current collector by an arbitrary coating method. And drying to form a positive electrode.

In the present invention, the positive electrode active material is not particularly limited, and lithium cobaltate composite oxide (LCO), lithium manganate composite oxide (LMO), lithium nickelate composite oxide (LNO), lithium-nickel- Lithium transition metals such as manganese-cobalt composite oxide (LNMCO), lithium-manganese-nickel composite oxide (LMNO), lithium-manganese-cobalt composite oxide (LMCO), lithium-nickel-cobalt composite oxide (LNCO) A composite oxide can be used. For example, as the positive electrode active material, the composition formula Li _{1 + α} Ni _x Mn _y Co _z Me _β O ₂ (where α, β, x, y, and z are −1 <α ≦ 0.5, 0 ≦ β <0.3, , 0 <x <1, 0 <y <1, 0 <z <1, x + y + z = 1, and Me is a metal element other than Ni, Mn, and Co). be able to. Further, the positive electrode active material may be a mixture of the above materials. The positive electrode active material may be an olivine-based material such as LiFePO ₄ .

  In the present invention, the binder is not particularly limited, and various resins such as polyethylene, polyvinylidene fluoride, polyhexafluoropropylene, polytetrafluoroethylene, polyethylene oxide, and carboxymethyl cellulose can be used.

  The organic solvent is not particularly limited, and examples thereof include basic solvents such as dimethyl sulfoxide, dimethylformamide, N-methylpyrrolidone, propylene carbonate, diethyl carbonate, dimethyl carbonate, and γ-butyrolactone, acetonitrile, tetrahydrofuran, Nonaqueous solvents such as nitrobenzene and acetone, and protic solvents such as methanol and ethanol can be used. Moreover, the kind of organic solvent, the compounding ratio of the organic compound and the organic solvent, the kind of additive and the amount of addition thereof, and the like can be arbitrarily set in consideration of the required characteristics and productivity of the secondary battery.

  Next, as shown in FIG. 1, the positive electrode 14 obtained above is impregnated in the electrolyte, so that the positive electrode 14 is infiltrated with the electrolyte, and then the positive electrode current collector at the center of the bottom of the case 11 that also serves as the positive electrode terminal. The positive electrode 14 is placed on the top. Thereafter, the separator 16 impregnated with the electrolyte is laminated on the positive electrode 14, the negative electrode 15 and the current collector plate 17 are sequentially laminated, and the electrolyte is injected into the internal space. Then, a metal spring member 18 is placed on the current collector plate 17, and a gasket 13 is arranged on the periphery, and a sealing plate 12 that also serves as a negative electrode terminal is fixed to the case 11 with a caulking machine or the like to seal the exterior. By doing so, the coin-type non-aqueous electrolyte secondary battery 1 is manufactured.

The electrolyte is interposed between the positive electrode 14 and the negative electrode 15 which is a counter electrode, and transports charge carriers between the two electrodes. As such an electrolyte, an electrolyte having an ionic conductivity of 10 ⁻⁵ to 10 ⁻¹ S / cm at room temperature can be used. For example, an electrolytic solution in which an electrolyte salt is dissolved in an organic solvent can be used. Here, as the electrolyte salt, for example, LiPF ₆ , LiClO ₄ , LiAsF ₆ , LiBF ₄ , LiCF ₃ SO ₃ , Li (CF ₃ SO ₂ ) ₂ , Li (CF ₃ SO ₂ ) ₂ N, Li (C ₂₎ F ₅ SO ₂ ) ₂ N, Li (CF ₃ SO ₂ ) ₃ C, Li (C ₂ F ₅ SO ₂ ) ₃ C, or the like can be used alone or in combination of two or more.

  As the organic solvent, ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, γ-butyrolactone, tetrahydrofuran, dioxolane, sulfolane, dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone, etc. are used. be able to.

Moreover, you may use a solid electrolyte for electrolyte. Examples of the polymer compound used in the solid electrolyte include polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene copolymer, vinylidene fluoride-ethylene copolymer, vinylidene fluoride-monofluoroethylene copolymer, and fluoride. Vinylidene fluoride-based polymers such as vinylidene-trifluoroethylene copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene terpolymer, and acrylonitrile-methyl methacrylate copolymer Polymer, acrylonitrile-methyl acrylate copolymer, acrylonitrile-ethyl methacrylate copolymer, acrylonitrile-ethyl acrylate copolymer, acrylonitrile-methacrylic acid copolymer, acrylonitrile-acrylic Acrylic nitrile polymers such as formic acid copolymer, acrylonitrile-vinyl acetate copolymer, polyethylene oxide, ethylene oxide-propylene oxide copolymer, and polymers of these acrylates and methacrylates. Can do. Moreover, you may use what made these polymer compounds contain electrolyte solution and made it gelatinous as electrolyte. Alternatively, only a polymer compound containing an electrolyte salt may be used as an electrolyte as it is. An inorganic solid electrolyte such as sulfide glass represented by Li ₂ S—P ₂ S ₅ system, Li ₂ S—B ₂ S ₃ system, and Li ₂ S—SiS ₂ system may be used as the electrolyte.

  The separator is not particularly limited, and conventionally known separators can be used. In the present invention, the separator is not limited by its name, and a solid electrolyte or gel electrolyte having a function (role) as a separator may be used instead of the separator. Further, a separator containing an inorganic material such as alumina or zirconia may be used.

  In the above embodiment, the coin-type secondary battery has been described. However, the battery shape is not particularly limited, and can be applied to a cylindrical type, a square type, a sheet type, and the like. Also, the exterior method is not particularly limited, and a metal case, mold resin, aluminum laminate film, or the like may be used.

  The “non-aqueous electrolyte secondary battery” in the present invention is a battery including a battery pack provided with a mechanism for detecting voltage, a function for controlling charge / discharge, a charger equipped with a function for controlling charge / discharge, and the like. System also means.

  Next, examples of the present invention will be specifically described. In addition, the Example shown below is an example and this invention is not limited to the following Example.

  Hereinafter, Examples 1 to 5 and Comparative Example 1 of a coin-type nonaqueous electrolyte secondary battery using metal tin as an electrode (negative electrode) will be described.

Example 1
A coin-type non-aqueous electrolyte secondary battery as shown in FIG. 1 was produced using metallic tin as an electrode (negative electrode).

  As shown in FIG. 1, a coin-type nonaqueous electrolyte secondary battery 1 includes a case 11 that also serves as a positive electrode terminal, a sealing plate 12 that also serves as a negative electrode terminal, and a gasket 13 that insulates the case 11 and the sealing plate 12. The positive electrode 14, the negative electrode 15, the separator 16 interposed between the positive electrode 14 and the negative electrode 15, the current collector plate 17 disposed on the negative electrode 15, and between the current collector plate 17 and the sealing plate 12. It is comprised from the arrange | positioned spring member 18, and the inside of case 11 is filled with electrolyte solution.

  Specifically, a tin plating film having a thickness of 5 μm was formed on a copper foil having a thickness of 10 μm by electrolytic plating. This copper foil was punched out into a circle having a diameter of 14 mm to produce a negative electrode (evaluation electrode) 15. Metal lithium was used for the positive electrode (counter electrode) 14. As the electrolytic solution, an organic electrolytic solution in which 1 mole of lithium hexafluorophosphate was dissolved per liter of the solvent in a solvent in which ethylene carbonate and diethyl carbonate were mixed at a weight ratio of 3: 7 was used. A polyethylene porous membrane was used as the separator 16. In this way, a coin-type non-aqueous electrolyte secondary battery 1 having a diameter of 20 mm and a thickness of 3.2 mm was produced.

  A charge / discharge cycle test was performed using the coin-type non-aqueous electrolyte secondary battery 1 manufactured as described above. Specifically, after charging and discharging once in a voltage range of 0.2 V to 1.0 V at a current value of 0.1 mA and stabilizing, 0.2 mA to 1 at a current value of 0.2 mA. A cycle test was conducted by repeating charge and discharge 10 times in a voltage range of 0.0V. Here, the case where the battery voltage is reduced by inserting lithium into the tin plating film used as the material of the negative electrode 15 is defined as charging.

  As shown in FIG. 2, as a result of this cycle test, the initial charge capacity is 559 mAh / g per weight of tin (Sn), and the initial discharge capacity is 558 mAh / g per weight of Sn. It can be seen that the discharge capacity at the 10th time is 554 mAh / g per Sn weight and 564 mAh / g per Sn weight. Therefore, good charge / discharge cycle performance with little capacity reduction was obtained.

Further, the density of the Sn plating film was 6.5 g / cm ³ . Discharge capacity per volume of Sn calculated from this value, the charge capacity of the first-time 3634mAh / cm ^3, the initial discharge capacity showed a high value and 3627mAh / cm ^3.

  From the above, it can be seen that in the coin-type non-aqueous electrolyte secondary battery 1 manufactured as Example 1 of the present invention, capacity reduction due to charge / discharge cycles can be suppressed.

(Example 2)
A coin-type nonaqueous electrolyte secondary battery 1 was produced in the same manner as in Example 1 except that the charge / discharge range during the charge / discharge cycle test was changed from 0.3 V to 1.0 V. A charge / discharge cycle test was performed using the secondary battery 1.

  As shown in FIG. 2, as a result of this cycle test, the initial charge capacity was 521 mAh / g per Sn weight, the first discharge capacity was 515 mAh / g per Sn weight, and the 10th charge capacity was Sn weight. It can be seen that the discharge capacity at the 10th time is 525 mAh / g per weight and 510 mAh / g per weight of Sn. Therefore, good charge / discharge cycle performance with little capacity reduction was obtained.

Further, the density of the Sn plating film was 6.5 g / cm ³ . Discharge capacity per volume of Sn calculated from this value, the charge capacity of the first-time 3387mAh / cm ^3, the initial discharge capacity showed a high value and 3348mAh / cm ^3.

  From the above, it can be seen that in the coin-type non-aqueous electrolyte secondary battery 1 manufactured as Example 2 of the present invention, capacity reduction due to charge / discharge cycles can be suppressed.

(Comparative Example 1)
A coin-type nonaqueous electrolyte secondary battery 1 was produced in the same manner as in Example 1 except that the charge / discharge range during the charge / discharge cycle test was changed from 0.1 V to 1.0 V. A charge / discharge cycle test was performed using the secondary battery 1.

  As shown in FIG. 2, as a result of this cycle test, the initial charge capacity increased to 680 mAh / g per Sn weight as compared with Examples 1 and 2, but the initial discharge capacity was 430 mAh per Sn weight. The charge capacity at the third time was 208 mAh / g per Sn weight, and the discharge capacity at the third time was as large as 88 mAh / g per Sn weight.

(Example 3)
A tin plating film having a thickness of 6 μm was formed on a copper foil having a thickness of 10 μm by electrolytic plating. The copper foil was punched out into a circle having a diameter of 14 mm to produce a negative electrode 15.

The positive electrode 14 was produced as follows. First, a lithium nickel cobalt composite oxide represented by Li (Ni _0.8 Co _0.2 ) O ₂ , acetylene black, and polyvinylidene fluoride are weighed so as to have a weight ratio of 85: 7.5: 7.5. These were mixed with N-methylpyrrolidone using a rotary blade type stirring device to prepare an electrode slurry. This electrode slurry was uniformly applied onto an aluminum current collector foil having a thickness of 20 μm by a doctor blade method, and N methylpyrrolidone was volatilized and dried by heating to a temperature of 140 ° C. Then, the aluminum collector foil with which the electrode slurry was apply | coated was roll-pressed, and the compound material sheet was produced. The composite material sheet was punched into a circle having a diameter of 12 mm to produce a positive electrode 14.

Here, the electrode weight per unit area (aluminum collector foil, excluding the weight of the copper foil) is positive electrode 14 is 6.3 mg / cm ^2, a negative electrode 15 is 4.0 mg / cm ^2, the electrode density (aluminum The weight of the positive electrode 14 was 2.8 g / cm ³ , and the value of the negative electrode 15 was 6.7 g / cm ³ .

  As the electrolytic solution, an organic electrolytic solution in which 1 mol of lithium hexafluorophosphate was dissolved per liter of the solvent in a solvent in which ethylene carbonate and diethyl carbonate were mixed at a weight ratio of 3: 7 was used. A polyethylene porous membrane was used as the separator 16. In this way, a coin-type non-aqueous electrolyte secondary battery 1 having a diameter of 20 mm and a thickness of 3.2 mm was produced.

  A charge / discharge cycle test was performed using the coin-type non-aqueous electrolyte secondary battery 1 manufactured as described above. Specifically, after charging and discharging three times in a voltage range of 3.0 V to 4.1 V at a current value of 0.2 mA and stabilizing, a current value of 0.4 mA is set to 3.0 V to 4 A cycle test was performed by repeating charge and discharge 20 times in a voltage range of 1 V. Here, the case where a current is passed in the direction in which the battery voltage increases is defined as charging, and the opposite is defined as discharging.

  As shown in FIG. 3, as a result of this cycle test, it can be seen that the initial discharge capacity is 545 μAh and the 20th discharge capacity is 531 μAh. Therefore, good charge / discharge cycle performance with little capacity reduction was obtained.

  From the above, it can be seen that in the coin-type non-aqueous electrolyte secondary battery 1 manufactured as Example 3 of the present invention, capacity reduction due to charge / discharge cycles can be suppressed.

Example 4
A tin plating film having a thickness of 6 μm was formed on a copper foil having a thickness of 10 μm by electrolytic plating. The copper foil was punched out into a circle having a diameter of 14 mm to produce a negative electrode 15.

The positive electrode 14 was produced as follows. First, a lithium nickel cobalt composite oxide represented by Li (Ni _0.34 Mn _0.33 Co _0.33 ) O ₂ , acetylene black, and polyvinylidene fluoride in a weight ratio of 85: 7.5: 7.5 These were weighed, and these and N-methylpyrrolidone were mixed using a rotating blade type stirring device to prepare an electrode slurry. This electrode slurry was uniformly applied onto an aluminum current collector foil having a thickness of 20 μm by a doctor blade method, and N methylpyrrolidone was volatilized and dried by heating to a temperature of 140 ° C. Then, the aluminum collector foil with which the electrode slurry was apply | coated was roll-pressed, and the compound material sheet was produced. The composite material sheet was punched into a circle having a diameter of 12 mm to produce a positive electrode 14.

Here, the electrode weight per unit area (aluminum collector foil, excluding the weight of the copper foil) is positive electrode 14 is 7.7 mg / cm ^2, a negative electrode 15 is 4.0 mg / cm ^2, the electrode density (aluminum The weight of the positive electrode 14 was 2.8 g / cm ³ , and the value of the negative electrode 15 was 6.7 g / cm ³ .

  As the electrolytic solution, an organic electrolytic solution in which 1 mol of lithium hexafluorophosphate was dissolved per liter of the solvent in a solvent in which ethylene carbonate and diethyl carbonate were mixed at a weight ratio of 3: 7 was used. A polyethylene porous membrane was used as the separator 16. In this way, a coin-type non-aqueous electrolyte secondary battery 1 having a diameter of 20 mm and a thickness of 3.2 mm was produced.

  A charge / discharge cycle test was performed using the coin-type non-aqueous electrolyte secondary battery 1 manufactured as described above. Specifically, after charging and discharging three times in a voltage range of 3.0 V to 4.1 V at a current value of 0.2 mA and stabilizing, a current value of 0.4 mA is set to 3.0 V to 4 A cycle test was performed by repeating charge and discharge 20 times in a voltage range of 1 V. Here, the case where a current is passed in the direction in which the battery voltage increases is defined as charging, and the opposite is defined as discharging.

  As shown in FIG. 3, as a result of this cycle test, it can be seen that the initial discharge capacity is 562 μAh and the 20th discharge capacity is 554 μAh. Therefore, good charge / discharge cycle performance with little capacity reduction was obtained.

  From the above, it can be seen that in the coin-type non-aqueous electrolyte secondary battery 1 manufactured as Example 4 of the present invention, capacity reduction due to charge / discharge cycles can be suppressed.

(Example 5)
The coin-type non-aqueous electrolyte secondary battery 1 was produced in the same manner as in Example 3 except that the charge / discharge range during the charge-discharge cycle test was changed from 3.0 V to 4.2 V. A charge / discharge cycle test was performed using the secondary battery 1.

As shown in FIG. 3, as a result of this cycle test, the initial discharge capacity increased to 580 μAh as compared with Examples 3 and 4, but the 20th discharge capacity became 524 μAh, and the capacity was greatly reduced. However, in Example 5, the capacity reduction was suppressed as compared with Comparative Example 1. From these things, when the lithium nickel manganese cobalt composite oxide as shown by Li (Ni _0.8 Co _0.2 ) O ₂ is used as the positive electrode material, the battery voltage is set to 4.1 V or less. It turns out that a capacity | capacitance fall can be suppressed further.

  It should be considered that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is shown not by the above embodiments and examples but by the scope of claims, and is intended to include all modifications and variations within the meaning and scope equivalent to the scope of claims. .

  According to the present invention, in a non-aqueous electrolyte secondary battery using a material containing Sn as an electrode, the capacity drop associated with the charge / discharge cycle can be reduced. A lithium ion secondary battery having a capacity can be realized.

1: Coin-type non-aqueous electrolyte secondary battery, 11: case, 12: sealing plate, 13: gasket, 14: positive electrode, 15: negative electrode, 16: separator, 17: current collector plate, 18: spring member.

Claims (9)

A nonaqueous electrolyte secondary battery using metallic tin as an electrode,
A nonaqueous electrolyte secondary battery in which the potential of the electrode during charging is 0.2 V or more on the basis of Li / Li ⁺ . A non-aqueous electrolyte secondary battery using a lithium-containing material as a positive electrode and metal tin as a negative electrode,
A nonaqueous electrolyte secondary battery in which the potential of the negative electrode during charging is 0.2 V or more on the basis of Li / Li ⁺ .   The nonaqueous electrolyte secondary battery according to claim 2, wherein a lithium transition metal composite oxide is used for the positive electrode. The lithium transition metal composite oxide has a composition formula Li _{1 + α} Ni _x Mn _y Co _z Me _β O ₂ (where α, β, x, y and z are −1 <α ≦ 0.5, 0 ≦ β <0. 3, 0 <x <1, 0 <y <1, 0 <z <1, x + y + z = 1, and Me is a metal element other than Ni, Mn, and Co). The nonaqueous electrolyte secondary battery according to claim 3.   The nonaqueous electrolyte secondary battery according to claim 4, wherein the battery voltage during charging is 4.1 V or less.   The nonaqueous electrolyte secondary battery according to any one of claims 2 to 5, wherein the negative electrode is metallic tin formed on a metal foil that is not alloyed with lithium. The nonaqueous electrolyte secondary battery according to claim 6, wherein the negative electrode is metal tin formed on a copper foil and having a density of 6 g / cm ³ or more. A method for charging a non-aqueous electrolyte secondary battery using a lithium-containing material as a positive electrode and metal tin as a negative electrode,
A method for charging a non-aqueous electrolyte secondary battery, wherein the potential of the negative electrode during charging is 0.2 V or more on the basis of Li / Li ⁺ . The method for charging a non-aqueous electrolyte secondary battery according to claim 8, wherein the lithium transition metal composite oxide is used for the positive electrode, and the battery voltage during charging is 4.1 V or less.

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