JP5510382B2 - Non-aqueous electrolyte secondary battery electrode material, non-aqueous electrolyte secondary battery electrode, and non-aqueous electrolyte secondary battery - Google Patents

Description

  The present invention relates to an electrode material for a non-aqueous electrolyte secondary battery, an electrode for a non-aqueous electrolyte secondary battery, and a non-aqueous electrolyte secondary battery.

  Currently, a carbonaceous material capable of occluding and releasing lithium is widely used for the negative electrode of a non-aqueous electrolyte battery typified by a lithium ion secondary battery. However, since a non-aqueous electrolyte battery having a high volumetric energy density is required, research using an alloy as a negative electrode material capable of occluding and releasing lithium has recently attracted attention again.

Patent Document 1 discloses that a La _0.6 Co _0.4 Sn ₃ alloy or the like is used as a negative electrode active material for a lithium ion secondary battery. However, although the volume energy density has been reported to be relatively large, when this material is applied to a practical non-aqueous electrolyte battery, as shown in Comparative Example 7 in Patent Document 2, charging / discharging is also performed. There was a problem that the cycle performance was not sufficient.

Patent Documents 2 to 4 describe using an alloy having a La ₃ Co ₂ Sn ₇ type crystal structure. However, there is a problem that the volume energy density is small.
JP 2003-197188 A JP-A-2005-310739 JP 2007-073215 A JP 2010-218855 A

  This invention is made | formed in view of the said problem, and it aims at providing the electrode material for nonaqueous electrolyte secondary batteries which is excellent in the volume energy density at the time of repeating charging / discharging.

The present invention contains La, Co, and Sn. When each elemental composition is La: Co: Sn = a: b: c (a + b + c = 100), 19 ≦ b ≦ 25; It is an electrode material for a nonaqueous electrolyte secondary battery including an alloy satisfying 25 ≦ a / c ≦ 0.30. The alloy is characterized by containing a cubic La ₃ Co ₄ Sn ₁₃ type alloy phase. Moreover, this invention is an electrode for nonaqueous electrolyte secondary batteries containing the said electrode material for nonaqueous electrolyte secondary batteries. Moreover, this invention is a nonaqueous electrolyte secondary battery provided with the said electrode for nonaqueous electrolyte secondary batteries.

  ADVANTAGE OF THE INVENTION According to this invention, the electrode material for nonaqueous electrolyte secondary batteries which is excellent in the volume energy density at the time of charging / discharging can be provided. Moreover, the electrode for nonaqueous electrolyte secondary batteries which can be set as the nonaqueous electrolyte secondary battery excellent in the volume energy density at the time of repeating charging / discharging can be provided. Moreover, the nonaqueous electrolyte secondary battery excellent in the volume energy density at the time of repeating charging / discharging can be provided.

  In the present invention, when the electrode material for a non-aqueous electrolyte secondary battery contains La, Co, and Sn, and each elemental composition is La: Co: Sn = a: b: c (a + b + c = 100), 19 It is characterized by including an alloy satisfying ≦ b ≦ 25 and 0.25 ≦ a / c ≦ 0.30. As long as the alloy exhibits the effects of the present invention, it does not prevent the alloy from containing elements other than La, Co, and Sn. Even when the alloy contains an element other than La, Co, and Sn, the general formula is interpreted as satisfying the above relational expression for the element composed of La, Co, and Sn contained in the alloy. .

Further, the electrode material for a non-aqueous electrolyte secondary battery according to the present invention is characterized by containing a cubic La ₃ Co ₄ Sn ₁₃ type alloy phase, but as long as the effects of the present invention are exhibited, the alloy phase Does not interfere with the existence of other phases.

  The electrode for a nonaqueous electrolyte secondary battery according to the present invention contains a metal powder, an alloy, a carbonaceous material, a conductive polymer, a binder, etc. as a material other than the electrode material for the nonaqueous electrolyte secondary battery. May be.

  The electrode for a nonaqueous electrolyte secondary battery according to the present invention is preferably used as a negative electrode for a nonaqueous electrolyte secondary battery.

  The method for producing the electrode material for a non-aqueous electrolyte secondary battery according to the present invention is not limited, and a general method for producing an alloy known as a technology for producing a hydrogen storage alloy can be employed. For example, a high frequency melting method, an arc melting method, a sintering method, a rapid quenching method, a strip casting method, an atomizing method, a plating method, a CVD method, a sputtering method, a rolling method and the like can be mentioned.

  As the atmosphere of the synthesis formation step, it is preferable to employ an inert gas atmosphere, a reduced pressure atmosphere or a vacuum. The temperature is preferably 1000 to 3000 ° C. The cooling rate is preferably 1 ° C./min or more.

  In general, in order to produce an alloy material, it is often necessary to rapidly cool the cooling step in which the temperature is lowered from the melted state and solidified. For example, in order to form the alloy material described in Patent Document 1, a rapid cooling process is required in which the mixture is melted and then cooled and solidified to a temperature below the freezing point at a cooling rate of 100 ° C./second or more. However, when manufacturing the electrode material for nonaqueous electrolyte secondary batteries according to the present invention, the cooling step can be greatly simplified. That is, in order to obtain the alloy phase according to the present invention satisfactorily, the rapid cooling process is not always necessary. Therefore, a special control device for rapid cooling is not particularly required in the production process of the electrode material for a non-aqueous electrolyte secondary battery according to the present invention. For example, in the examples described later, the molten alloy is cooled on copper hearth. That is, such a slow cooling condition can be adopted in the solidifying step of the electrode material for a non-aqueous electrolyte secondary battery according to the present invention.

  In general, after forming an alloy powder having a desired composition, a heat treatment step is often required before use. For example, in order to form the alloy material described in Patent Document 1, after forming the alloy powder, it is necessary to further perform a heat treatment step of maintaining the temperature in a temperature range of 250 to 700 ° C. for about 10 hours. However, when producing the electrode material for a non-aqueous electrolyte secondary battery according to the present invention, it is not always necessary to go through a special heat treatment step after forming the alloy. Therefore, the heat treatment step can be omitted in the production process of the electrode material for a nonaqueous electrolyte secondary battery according to the present invention. Rather, according to the knowledge of the present inventor, there is a knowledge that an electrode material for a non-aqueous electrolyte secondary battery with better charge / discharge cycle performance can be obtained by not providing a heat treatment step after forming the alloy.

  The electrode material for a non-aqueous electrolyte secondary battery according to the present invention can be used after pulverization after forming an alloy. The average particle size of the pulverized powder is preferably 100 μm or less. In particular, the average particle size of the powder after pulverization is preferably 10 μm or less in order to improve the high output characteristics of the nonaqueous electrolyte battery. In order to obtain the powder in a predetermined shape, a pulverizer or a classifier is used. The pulverization method is not limited, and for example, a mortar, a ball mill, a sand mill, a vibrating ball mill, a planetary ball mill, a jet mill, a counter jet mill, a swirling air flow type jet mill, and a sieve are used. At the time of pulverization, wet pulverization in which an organic solvent such as water or ethanol coexists may be used. There is no particular limitation on the classification method, and a sieve, an air classifier, or the like is used as needed for both dry and wet methods.

  The nonaqueous electrolyte used for the lithium secondary battery according to the present invention is not limited. As this electrolyte, those generally proposed for use in lithium batteries and the like can be used. Nonaqueous solvents used for the nonaqueous electrolyte include cyclic carbonates such as propylene carbonate, ethylene carbonate, butylene carbonate, chloroethylene carbonate and vinylene carbonate; cyclic esters such as γ-butyrolactone and γ-valerolactone; dimethyl carbonate, Chain carbonates such as diethyl carbonate and ethyl methyl carbonate; chain esters such as methyl formate, methyl acetate and methyl butyrate; tetrahydrofuran or derivatives thereof; 1,3-dioxane, 1,4-dioxane, 1,2-dimethoxy Ethers such as ethane, 1,4-dibutoxyethane and methyldiglyme; Nitriles such as acetonitrile and benzonitrile; Dioxolane or derivatives thereof; Ethylene sulfide, sulfolane, sultone or derivatives thereof Examples thereof include a conductor alone or a mixture of two or more thereof, but are not limited thereto.

Examples of the electrolyte salt used for the non-aqueous electrolyte include LiClO ₄ , LiBF ₄ , LiAsF ₆ , LiPF ₆ , LiSCN, LiBr, LiI, Li ₂ SO ₄ , Li ₂ B ₁₀ Cl ₁₀ , NaClO ₄ , NaI, NaSCN, NaBr , KClO ₄ , KSCN, and other inorganic ion salts containing one of lithium (Li), sodium (Na), or potassium (K), LiCF ₃ SO ₃ , LiN (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ (SO ₂ ) ₂ , LiN (CF ₃ SO ₂ ) (C ₄ F ₉ SO ₂ ), LiC (CF ₃ SO ₂ ) ₃ , LiC (C ₂ F ₅ SO ₂ ) ₃ , (CH ₃ ) ₄ NBF ₄ , ( CH ₃ ) ₄ NBr, (C ₂ H ₅ ) ₄ NClO ₄ , (C ₂ H ₅ ) ₄ NI, (C ₃ H ₇ ) ₄ NBr, (n-C ₄ H ₉ ) ₄ NClO ₄ , (nC ₄ H ₉ ) ₄ NI, (C ₂ H ₅ ) ₄ N-maleate, (C ₂ H ₅ ) ₄ N-benzoate, (C ₂ H ₅ ) ₄ N-phthalate, Examples thereof include organic ionic salts such as lithium stearyl sulfonate, lithium octyl sulfonate, and lithium dodecylbenzene sulfonate. These ionic compounds can be used alone or in admixture of two or more. For example, a mixture of LiPF ₆ and a lithium salt having a perfluoroalkyl group such as LiN (C ₂ F ₅ SO ₂ ) ₂ may be used.

  Moreover, you may use normal temperature molten salt and an ionic liquid as a nonaqueous electrolyte.

  The concentration of the electrolyte salt in the non-aqueous electrolyte is preferably 0.1 mol / l to 5 mol / l, more preferably 0.5 mol / l to obtain a non-aqueous electrolyte battery having excellent battery characteristics. 2.5 mol / l.

  Hereinafter, the case where the electrode material for a nonaqueous electrolyte secondary battery is used in the negative electrode will be described as an example.

The positive electrode material used for the positive electrode of the counter electrode is not limited, and lithium transition metal composite oxide, lithium transition metal lithium compound, conductive polymer, activated carbon and the like can be used alone or in combination. Examples of the lithium transition metal composite oxide include α-NaFeO such as LiCoO ₂ , LiNi _0.4 Mn _0.4 Co _0.2 O ₂ , Li _1.2 Co _0.1 Ni _0.15 Mn _0.55 O _2. Examples thereof include a layered compound having a type ₂ crystal structure and a compound having a spinel type crystal structure typified by LiMn ₂ O ₄ and LiNi _1.5 Mn _0.5 O ₄ . Examples of the lithium transition metal lithium compound include LiFePO ₄ , LiMn _0.8 Fe _0.2 PO ₄ , and Li ₃ V ₂ (PO ₄ ) ₃ . Examples of the conductive polymer include polypyrrole and polyaniline. Disulfide compounds may be used.

  The average particle size of the positive electrode active material powder is preferably 100 μm or less. In particular, the size of the positive electrode active material powder is preferably 10 μm or less in order to improve the high output characteristics of the nonaqueous electrolyte battery. In order to obtain the powder in a predetermined shape, a pulverizer or a classifier is used. For example, a mortar, a ball mill, a sand mill, a vibrating ball mill, a planetary ball mill, a jet mill, a counter jet mill, a swirling air flow type jet mill, a sieve, or the like is used. At the time of pulverization, wet pulverization in which an organic solvent such as hexane or water coexists can be used. The classification method is not particularly limited. In both dry and wet classification, a sieve, an air classifier, or the like is used as necessary.

  In the positive electrode and the negative electrode, in addition to the main constituent components, a conductive agent, a binder, a thickener, a filler, and the like may be contained as other constituent components.

  The conductive agent is not limited as long as it is an electron conductive material that does not adversely affect battery performance. For example, natural graphite (such as scaly graphite, scaly graphite, earthy graphite), artificial graphite, carbon black, acetylene black, ketjen black, carbon whisker, carbon fiber, metal powder, metal fiber, conductive ceramic material, etc. 1 Species or mixtures thereof can be included as a conductive agent.

  In these, it is preferable to use acetylene black as a electrically conductive agent from a viewpoint of electronic conductivity and coating property. The addition amount of the conductive agent is preferably 0.1% by weight to 50% by weight, and particularly preferably 0.5% by weight to 30% by weight with respect to the total weight of the positive electrode or the negative electrode. In particular, it is preferable to use acetylene black by pulverizing it into ultrafine particles of 0.1 to 0.5 μm because the necessary carbon amount can be reduced. The mixing by these mixing methods is physical mixing, and the ideal is uniform mixing. Therefore, it is possible to mix by a dry type or a wet type using a powder mixer such as a V-type mixer, an S-type mixer, a grinding machine, a ball mill, or a planetary ball mill.

  As the binder, thermoplastic resins such as polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyethylene, and polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, and styrene are usually used. One of polymers having rubber elasticity such as butadiene rubber (SBR) or fluoro rubber, or a mixture thereof can be used. The addition amount of the binder is preferably 1 to 50% by weight, particularly 2 to 30% by weight, based on the total weight of the positive electrode or the negative electrode.

  The filler is not particularly limited as long as it does not adversely affect the battery performance. Usually, olefin polymers such as polypropylene and polyethylene, amorphous silica, alumina, zeolite, glass, carbon and the like are used. The added amount of the filler is preferably 30% by weight or less based on the total weight of the positive electrode or the negative electrode.

  The positive electrode and the negative electrode contain a positive electrode active material or negative electrode material and other materials, and form a mixture using N-methylpyrrolidone, toluene or the like as a solvent, and apply the mixture on the current collector described in detail below. It is preferably produced by, for example, removing the solvent component by heat treatment at a temperature of about 50 ° C. to 250 ° C. for about 2 hours. About the application method, for example, it is preferable to apply to any thickness and any shape using means such as roller coating such as applicator roll, screen coating, doctor blade method, spin coating, bar coater, etc. It is not limited.

  As the separator, it is preferable to use a porous film or a non-woven fabric exhibiting excellent high rate discharge performance alone or in combination. Examples of the material constituting the separator for a non-aqueous electrolyte battery include polyolefin resins typified by polyethylene, polypropylene, etc., polyester resins typified by polyethylene terephthalate, polybutylene terephthalate, etc., polyvinylidene fluoride, vinylidene fluoride- Hexafluoropropylene copolymer, vinylidene fluoride-perfluorovinyl ether copolymer, vinylidene fluoride-tetrafluoroethylene copolymer, vinylidene fluoride-trifluoroethylene copolymer, vinylidene fluoride-fluoroethylene copolymer, Vinylidene fluoride-hexafluoroacetone copolymer, vinylidene fluoride-ethylene copolymer, vinylidene fluoride-propylene copolymer, vinylidene fluoride-trifluoropropylene copolymer, vinylidene fluoride Down - tetrafluoroethylene - hexafluoropropylene copolymer, vinylidene fluoride - ethylene - can be mentioned tetrafluoroethylene copolymer.

  The porosity of the separator is preferably 98% by volume or less from the viewpoint of strength. From the viewpoint of charge / discharge characteristics, the porosity is preferably 20% by volume or more.

  As the separator, for example, a polymer gel composed of a polymer such as acrylonitrile, ethylene oxide, propylene oxide, methyl methacrylate, vinyl acetate, vinyl pyrrolidone, and polyvinylidene fluoride and an electrolyte may be used. The use of the nonaqueous electrolyte in the gel state as described above is preferable because it has an effect of preventing leakage.

  Furthermore, it is preferable to use a polymer gel in combination with the above-described porous film, nonwoven fabric or the like as the separator because the liquid retention of the electrolyte is improved. That is, a film is formed by coating the surface of the polyethylene microporous membrane and the microporous wall with a solvophilic polymer having a thickness of several μm or less, and the electrolyte is retained in the micropores of the film. Solvent polymer gels.

  Examples of the solvophilic polymer include polyvinylidene fluoride, an acrylate monomer having an ethylene oxide group or an ester group, an epoxy monomer, a polymer having a monomer having an isocyanate group, and the like crosslinked. It is possible to crosslink the monomer by heating a material obtained by adding a radical initiator to such a monomer, or by irradiating an active ray such as an ultraviolet ray (UV) or an electron beam (EB). .

  The structure of the lithium secondary battery is not particularly limited. Examples of this structure include a cylindrical battery having a positive electrode, a negative electrode, and a roll separator, a square battery, a flat battery, and the like.

  Hereinafter, the present invention will be described more specifically with reference to examples.

[Example 1]
(Preparation of La _16.25 Co ₂₀ Sn _63.75 )
As the alloy material, each metal was cut out from each ingot of La, Co, and Sn. Since La is easily oxidized, the surface oxide film is handled with a file removed. Each metal was weighed so that the element ratio was La: Co: Sn = 16.25: 20: 63.75, and dissolved by a micro vacuum arc melting apparatus (manufactured by Nisshin Giken Co., Ltd., model number: NEV-AD03). It mixed and mounted on the indoor water-cooled copper hearth. The melting chamber was evacuated and the operation of introducing argon gas to -0.005 MPa was repeated twice. After evacuating again, argon gas was introduced to -0.04 MPa. In this way, the atmosphere in the dissolution chamber was replaced with argon gas. Next, the placed alloy raw material was arc-melted by the following procedure. First, the alloy raw material was uniformly applied with an arc to dissolve the metal components so that they were uniformly mixed, and then cooled and solidified on a water-cooled copper hearth. The solidified melted lump was turned over, and the back surface was melted by applying an arc again and then cooled on a water-cooled copper hearth to solidify. Such an operation of dissolving the front surface and an operation of dissolving the back surface were taken as one set, and this was repeated 5 sets. The arc current value was 50 A for the first set and 100 A for the second to fifth sets. In the process of cooling and solidifying on a water-cooled copper hearth, it takes about 15 minutes to solidify. That is, this cooling process is slow cooling.

  The alloy ingot thus obtained was pulverized using a stainless steel mortar and then sieved to less than 125 μm using a sieve. Next, this was further pulverized using a planetary ball mill apparatus. That is, after putting 10 stainless steel balls with a diameter of 10 mm into a stainless steel ball mill pot with an internal volume of 80 ml, 3 g of the alloy powder was added together with 0.1 ml of isopropanol as a dispersant, the rotation speed was 150 rpm, and the set time was Ball milling was performed under the condition of 12 hours. In order to prevent the oxidation of the alloy, all the operations for charging and removing the alloy powder from the ball mill pot were performed in a glove box substituted with argon. After ball milling, in order to further remove coarse powder, it was screened to less than 25 μm using a sieve. In this way, an electrode material for a nonaqueous electrolyte secondary battery according to Example 1 was produced.

[Example 2]
(Preparation of La _16.5 Co ₂₁ Sn _62.5 )
The nonaqueous electrolyte according to Example 2 was the same as Example 1 except that each metal was weighed so that the element ratio was La: Co: Sn = 16.5: 21: 62.5. An electrode material for a secondary battery was produced.

[Example 3]
(Preparation of La ₁₇ Co ₂₀ Sn ₆₃ )
For the nonaqueous electrolyte secondary battery according to Example 3, except that each metal was weighed so that the element ratio was La: Co: Sn = 17: 20: 63 An electrode material was prepared.

[Example 4]
(Preparation of La _17.5 Co ₂₀ Sn _62.5 )
The nonaqueous electrolyte according to Example 4 is the same as Example 1 except that each metal is weighed so that the element ratio is La: Co: Sn = 17.5: 20: 62.5. An electrode material for a secondary battery was produced.

[Example 5]
(Preparation of La ₁₈ Co ₂₀ Sn ₆₃ )
For the nonaqueous electrolyte secondary battery according to Example 5, except that each metal was weighed so that the element ratio was La: Co: Sn = 18: 20: 63 An electrode material was prepared.

[Comparative Example 1]
(Preparation of La ₁₅ Co ₂₀ Sn ₆₅ )
For the nonaqueous electrolyte secondary battery according to Comparative Example 1, except that each metal was weighed so that the element ratio was La: Co: Sn = 15: 20: 65 An electrode material was prepared.

[Comparative Example 2]
(Preparation of La ₂₀ Co ₂₀ Sn ₆₀ )
For the nonaqueous electrolyte secondary battery according to Comparative Example 2, except that each metal was weighed so that the element ratio was La: Co: Sn = 20: 20: 60. An electrode material was prepared.

  With respect to the electrode materials for non-aqueous electrolyte secondary batteries according to the above Examples and Comparative Examples, X-ray diffraction measurement was performed using an X-ray diffraction measurement apparatus (Miniflex II, manufactured by Rigaku Corporation). The measurement conditions were a Cu tube, 30 kV, 15 mA, a step scan with an interval of 0.02 ° and an integration time of 2 s.

Further, the existence ratio of cubic La ₃ Co ₄ Sn ₁₃ type alloy phase was estimated by Rietveld analysis. The procedure and conditions of Rietveld analysis were based on “Practice of Powder X-ray Analysis—Introduction to Rietveld Method” (Izumi Nakai, Fujio Izumi, edited by Asakura Shoten, Page 58, 2002). That is, in the Rietveld analysis, the mass fraction of the phase is obtained by the following equation.
x1 = (s1 * Z1 * M1 * V1) / (Σi Si * Zi * Mi * Vi)
Where x1 is the mass fraction of the analysis component, si and s1 are the scale factors of component i and the analysis component, Zi and Z1 are the chemical formula numbers of component i and the analysis component in the unit cell, and Mi and M1 are the component i and the analysis component The chemical formula quantities Vi and V1 are the volume of the unit cell of component i and analysis component.

  The electrode materials for nonaqueous electrolyte secondary batteries according to the above examples and comparative examples are each used as a negative electrode active material, and the negative electrode active material, acetylene black, and polyvinylidene fluoride (PVdF) are contained at a mass ratio of 80:10:10 A negative electrode paste using N-methylpyrrolidone as a solvent was prepared. The negative electrode paste was applied to foamed nickel as an electrode substrate, and then dried at 150 ° C. under reduced pressure. Thus, the electrode for nonaqueous electrolyte secondary batteries was produced.

In order to evaluate the performance as a negative electrode of each of the electrodes for non-aqueous electrolyte secondary batteries produced in this manner, the electrode was used as a working electrode, metal Li was used as a counter electrode and a reference electrode, and ethylene carbonate (EC) and diethyl carbonate. A tripolar glass cell was assembled in a glove box under an argon atmosphere by using an electrolyte obtained by dissolving LiClO ₄ at a concentration of 1 mol / l in a solvent in which (DEC) was mixed at a volume ratio of 1: 1. In this way, a non-aqueous electrolyte secondary battery for negative electrode evaluation was produced.

For each non-aqueous electrolyte secondary battery produced in this manner, a charge / discharge test was repeatedly performed under the condition of 25 ° C., and the discharge capacities (Ah) of the first cycle and the tenth cycle were measured. The capacity density (Ah / cm ³ ) per volume of the negative electrode active material determined from the weight and true density was determined. Here, since the evaluation is performed as a negative electrode, in the following description, an operation of energizing the working electrode in the reduction direction is referred to as “charging”, and an operation of energizing in the oxidation direction is referred to as “discharging”. Charging was performed at a constant current and constant voltage with a current of 41.7 mA / g and 0.02 V (vs. Li / Li ⁺ ), and the constant voltage charging time was 8 hours. The discharge was a constant current discharge with a current of 41.7 mA / g and a discharge end potential of 3.5 V (vs. Li / Li ⁺ ). After the end of charging and after the end of discharging, a 60-minute rest period was provided.

The above results are shown in Table 1 together with the alloy composition.

  As can be seen from Table 1, the non-aqueous electrolyte secondary battery electrode materials according to Examples 1 to 5 have significantly higher discharge capacity at the 10th cycle than Comparative Examples 1 and 2. became. From this, the alloy which the electrode material for nonaqueous electrolyte secondary batteries contains La, Co, and Sn, and each elemental composition is set to La: Co: Sn = a: b: c (a + b + c = 100). 19 ≦ b ≦ 25, the non-aqueous electrolyte secondary battery is excellent in volumetric energy density when charging / discharging is repeated by setting the value of a / c to 0.25 or more and 0.30 or less. It can be seen that an electrode material can be provided.

The working electrode provided in Example 1 was subjected to X-ray diffraction measurement before and after repeated charge and discharge, and is shown in FIG. Here, the electrode material was not disassembled from the working electrode, and was used for the measurement in the state of a plate-like electrode. The observed nickel (Ni) peak is derived from the nickel foam used for the electrode substrate, and the polyethylene (PE) peak is a polychucked electrode that wraps the electrode to prevent oxidation and moisture from the active material. It comes from the bag. From FIG. 1, it can be seen that the cubic La ₃ Co ₄ Sn ₁₃ type alloy phase is maintained even after repeated charge and discharge.

It is an X-ray diffraction pattern of the electrode for nonaqueous electrolyte secondary batteries concerning the present invention.

Claims (4)

When La, Co, and Sn are included, and each elemental composition is La: Co: Sn = a: b: c (a + b + c = 100), 19 ≦ b ≦ 25 and 0.25 ≦ a / The electrode material for nonaqueous electrolyte secondary batteries containing the alloy which is c <= 0.30. The electrode material for a nonaqueous electrolyte secondary battery according to claim 1, wherein the alloy contains a cubic La ₃ Co ₄ Sn ₁₃ type alloy phase. The electrode for nonaqueous electrolyte secondary batteries containing the electrode material for nonaqueous electrolyte secondary batteries of Claim 1 or 2. A nonaqueous electrolyte secondary battery comprising the electrode for a nonaqueous electrolyte secondary battery according to claim 3.