JP2002260650A - Battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrode material for a battery having high conductivity, to provide a battery having high voltage, high energy density, excellent charge / discharge cycle performance, and excellent safety. And SOLUTION: The alloy includes an alloy of an A phase and a B phase, wherein the A phase and the B phase include at least one or more common elements, and the A phase is reversible in the battery. A metal, an intermetallic compound or a solid solution capable of performing a charge / discharge reaction, wherein the B phase has electron conductivity and is a metal which is electrochemically inactive in the battery in a charge / discharge potential range of the battery; The above problem can be solved by using an electrode made of an intermetallic compound or a solid solution.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a battery using an alloy as an electrode material.

[0002]

2. Description of the Related Art Primary batteries such as Lucranche dry batteries, alkaline dry batteries and lithium primary batteries, and secondary batteries such as lead batteries, nickel cadmium batteries, nickel hydrogen batteries, nickel zinc batteries and lithium ion batteries are known. is there. In the case of a secondary battery in which metal ions such as zinc and lithium participate in the electrode reaction, the metal may be deposited on the electrode in a resinous state (dendritic deposition), which may lower the cycle performance. In addition, the dendrite deposition may penetrate the separator, cause an internal short circuit, or cause ignition. For example, in lithium secondary batteries, studies have been made to use metallic lithium as a negative electrode active material,
The formation of the dendrites of lithium generated during charging has been a problem.

In lithium secondary batteries, studies have been made to use lithium alloys for the purpose of preventing the dendrite precipitation. However, due to deep charge / discharge or repeated charge / discharge, the lithium alloy is pulverized or dropped. Cause
There is a problem that the battery performance is reduced. In place of the above-mentioned metals and alloys, some batteries have been put into practical use to achieve long life and improved safety by using carbonaceous materials capable of occluding and releasing lithium ions for the negative electrode. However, in many of these carbonaceous materials, the doping potential of lithium to the carbonaceous material is close to 0 V with respect to the potential of metallic lithium. In some cases, lithium was deposited on the top.
This may cause an internal short circuit in the cell or a reduction in discharge efficiency. Although such carbonaceous materials have been considerably improved in terms of cycle performance, the capacity per unit volume is low because the energy density of carbonaceous materials as electrode materials is relatively small. become. That is, the carbonaceous material is still insufficient in terms of high energy density. In addition, in the case where a film needs to be formed on carbon, the initial charge / discharge efficiency decreases, and the amount of electricity used for forming the film is irreversible, which leads to a reduction in capacity corresponding to the amount of electricity.

On the other hand, as the negative electrode materials other than metallic lithium or lithium alloy, or a carbonaceous material, a composite oxide containing silicon and lithium _{Li x Si 1-y M y} O z ( JP-7-2
No. 30800) and an amorphous chalcogen compound M ¹ M ²
_p M ⁴ _q has been proposed to use (JP-A-7-288123 discloses), high capacity, are achieved some degree of improvement in terms of high energy density.

[0005] However, such composite oxides have a problem in high-rate charging and high-rate discharging performance due to the low electronic conductivity of the material itself. Attempts have been made to add a conductive agent to solve this problem. However, when a carbon material having a low density is used as the conductive agent, the capacity per volume is reduced. Furthermore, when a high-rate charge is performed by adding a conductive agent, current concentration partially occurs, and precipitation of lithium from the conductive agent is sometimes observed. for that reason,
In some cases, an internal short circuit of the cell was caused or the charge / discharge efficiency was reduced.

Further, since the composite oxide itself is an oxide itself, the reduction reaction of the composite oxide is considered to proceed concurrently with the reaction with lithium. Occurred, and the initial charge / discharge efficiency sometimes decreased.

On the other hand, the above-mentioned silicon simple substance and composite oxide are
Negative electrode such as silicide of non-ferrous metal composed of transition metal
The material is a negative electrode material with improved cycle life.
It is proposed in Japanese Patent Application Laid-Open No. Hei 7-240201. But
In addition, the charge / discharge cycle performance compared to the metallic lithium anode
Although the battery capacity has been improved, the battery capacity is
The amount has increased by only about 12%. in this way,
The silicide of the non-ferrous metal comprising the transition metal is not necessarily
Electrochemical that can efficiently occlude and release lithium ions
Not high activity, greatly improving battery capacity
I couldn't let it. For example, from the transition metal
CeSi as a non-ferrous metal silicide _TwoTake for example
And electron conductivity, but within the charge / discharge potential range
Was found to be electrochemically inert. Immediately
That is, all of the silicides proposed in the above publication are lithium
Is not capable of storing and releasing
Even with the use of silicides that are chemically inert, the discharge capacity is improved.
Couldn't be better.

Further, Japanese Patent Application Laid-Open No. 2000-30703 discloses that as a negative electrode material for a non-aqueous electrolyte secondary battery, a composite particle in which another solid phase B is wrapped around a solid phase A;
Is a solid solution or an intermetallic compound containing at least one kind of element that can form an alloy with lithium, or one kind of element that can form an alloy with lithium, or the solid phase B is a solid phase. Japanese Unexamined Patent Application Publication No. 2000-2000, which is formed from a solid solution or an intermetallic compound containing at least one element capable of being alloyed with lithium or lithium forming A, and a mixed conductor of lithium ions and electrons. -285919 discloses the entire surface or a part of the periphery of the core particle composed of the solid phase A,
Coated with a solid phase B, said solid phase A containing silicon as a constituent element, said solid phase B being a group 2 element, a transition element, a group 12, a group 13 element of the periodic table, and 1 excluding carbon and silicon;
A negative electrode material which is a solid solution or an intermetallic compound of at least one element selected from the group consisting of Group 4 elements and silicon has been proposed. However, since these electron-conductive coatings are only on the surface, they cannot cope with the electronic isolation of the negative electrode material due to the cracks of the particles generated when occluded lithium, so that the cycle deterioration is large. there were.

[0009]

As described above, the negative electrode material for a lithium secondary battery can be summarized as follows. When a lithium metal or lithium alloy is used, it is advantageous in terms of high voltage, high capacity, and high energy density. There are problems with performance and safety, and when using carbonaceous materials,
Although advantageous in terms of safety, it is insufficient in terms of high capacity and high energy density. Furthermore, when an oxide negative electrode is used, it seems to be improved in terms of high capacity and high energy density, but it is not satisfactory in terms of high voltage, charge / discharge efficiency, cycle performance and safety.

Therefore, at a high voltage and a high energy density,
In order to obtain batteries with excellent charge-discharge cycle characteristics and high safety, there is little change in the crystal system or volume change during charge / discharge, and reversibly charge / discharge batteries with high electron conductivity. The development of a substance was desired.

The present invention has been made in view of the above problems, and has little change in crystal system and volume during charge and discharge.
Another object of the present invention is to provide a battery electrode material that can be charged and discharged reversibly and has high electron conductivity. Further, it is another object of the present invention to provide a battery which exhibits excellent charge / discharge cycle performance at a high voltage and a high energy density and is excellent in safety by applying the battery electrode material to the battery.

[0012]

Means for Solving the Problems In order to achieve the above-mentioned object, the present inventors have conducted intensive studies and as a result, surprisingly, by using an alloy having a specific composition as a battery electrode, an excellent The inventors have found that a battery having battery characteristics can be obtained, and have reached the present invention. That is, the technical configuration of the present invention and the operation and effect thereof are as follows. However, the action mechanism includes estimation, and the correctness of the action mechanism is
It does not limit the invention.

According to a first aspect of the present invention, in a battery including a positive electrode, a negative electrode, and an electrolyte, at least one of the positive electrode and the negative electrode includes an alloy, and the alloy includes an A phase. An alloy with a B phase, wherein the A phase and the B phase contain at least one or more common elements, and the A phase is a metal, an intermetallic compound, or a solid solution capable of reversibly charging and discharging in the battery. Wherein the B phase has electron conductivity, and is made of a metal, an intermetallic compound, or a solid solution that is electrochemically inactive in the battery in the charge / discharge potential range of the battery. is there.

Here, the “battery charge / discharge potential range” refers to a charge and discharge potential as long as a recommended battery is used in a recommended environment described in a catalog or the like when the battery is sold. Abuse (overcharge, overdischarge, charge / discharge at a higher rate than specified, charge / discharge of batteries after the end of charge / discharge cycle life, charge / discharge at abnormally high temperatures, abnormalities such as internal short-circuit, etc.) Or use of a defective battery or other abuse) and leaving after the abuse are excluded. That is, if the metal `` electrochemically inert in the battery in the charge / discharge potential range of the battery '' is described by way of example, for example, when copper is used for a negative electrode current collector of a lithium battery, Copper does not elute into the electrolytic solution during normal use, but the copper may elute slightly depending on the abuse such as overcharging or after a long-term repeated charge / discharge cycle. In such a case, the copper corresponds to the "inert" metal herein. Further, the copper has a property of alloying with a very small amount of lithium, but if the alloying is not progressive, the lithium in the alloy can be electrochemically released by at least ordinary charge and discharge. Not even a thing. Therefore, also in this sense, the copper corresponds to the “inert” metal referred to herein. Conversely, what is not "inactive" refers to one that is active enough to participate in the electrode reaction of the battery. For example,
In a lithium battery, lead has the property of storing and releasing lithium in a large amount and reversibly, and can be used as a negative electrode material.
Does not hit metal.

According to such a configuration, the B phase has excellent electron conductivity, but hardly participates in the charge / discharge reaction. In addition, since the A phase and the B phase include at least one or more common elements, the A phase and the B phase can form a homogeneous alloy in a relatively wide arbitrary composition range. When such an alloy having two phases is charged and discharged as an electrode, the charge / discharge reaction proceeds reversibly with respect to the A phase, but the B phase is maintained with electron conductivity. That is, a large matrix having electron conductivity due to the B phase is formed in the alloy, and a charge / discharge reaction proceeds with respect to the A phase in the matrix, so that the crystal collapses and becomes fine powder. Alternatively, a phenomenon such as dropout is suppressed, an overvoltage accompanying a charge / discharge reaction is small, and an electrode material having high capacity and excellent reversibility is obtained.

In the present invention, the charge / discharge reaction is a reaction in which lithium ions participate in an electrode reaction, and the phase A electrochemically stores and releases lithium. It is characterized by being possible.

According to such a configuration, the B phase has excellent electron conductivity, but hardly alloys with lithium. In addition, since the A phase and the B phase include at least one or more common elements, the A phase and the B layer can form a homogeneous alloy in a relatively wide arbitrary composition range. When lithium is occluded in such an alloy having two phases, the alloying of lithium proceeds in the A phase, but the B phase absorbs lithium.
It cannot be released and is maintained with electronic conductivity. That is, a large matrix having electron conductivity due to the B phase is formed in the alloy, and the A phase in the matrix is alloyed with lithium, so that lithium is absorbed and released. Therefore, phenomena such as crystal disintegration, pulverization, or falling off are suppressed, and an overvoltage associated with the charge / discharge reaction is small, so that the electrode material has high capacity and excellent reversibility.

According to the present invention, the charge / discharge reaction is a reaction in which hydroxide ions participate in an electrode reaction, and the phase A electrochemically stores hydrogen. -It is characterized by being releasable.

According to this structure, the B phase has excellent electron conductivity, but hardly forms a hydride. In addition, since the A phase and the B phase include at least one or more common elements, the A phase and the B layer can form a homogeneous alloy in a relatively wide arbitrary composition range. When hydrogen is absorbed in such an alloy having two phases, the hydrogenation of the A phase proceeds, but the B phase cannot absorb and release hydrogen, and is maintained with electron conductivity.
That is, a large matrix having electron conductivity due to the B phase is formed in the alloy, and the A phase in the matrix is hydrogenated, whereby hydrogen is absorbed and released, so that the crystal is formed. Phenomena such as disintegration, pulverization or falling off are suppressed, and the overvoltage accompanying the charge / discharge reaction is small,
It becomes an electrode material with high capacity and excellent reversibility.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail, but the present invention is not limited by these descriptions.

The alloy used in the battery of the present invention is preferably a powder having an average particle size of 0.1 to 100 μm.
As means for obtaining such a powder, a pulverizer, a classifier, or the like can be used. For example, mortar, ball mill, sand mill, vibrating ball mill, planetary ball mill, jet mill, counter jet mill, swirling air jet mill,
A sieve or the like may be used. For the pulverization, a dry pulverization method may be used, or a wet pulverization method in which an organic solvent such as water or hexane coexists may be used. The classification method is not particularly limited, and a sieve, an air classifier, or the like may be used for both dry and wet as required.

When the alloy used in the battery of the present invention is used as a powder, a conductive agent, a binder, a filler and the like may be added to the electrode mixture.

The conductive agent may be any conductive material that does not adversely affect the battery performance. Usually, natural graphite (flaky graphite, flaky graphite, earthy graphite, etc.), artificial graphite, carbon black, acetylene black, Ketjen black, carbon whiskers, carbon fibers and metals (copper, nickel, aluminum, silver, gold, etc.) Conductive materials such as powder, metal fibers, metal deposits, and conductive ceramic materials can be included as one type or a mixture thereof. Among these, it is preferable to use a mixture of graphite, acetylene black and Ketjen black.
The addition amount is preferably 1 to 50% by weight, particularly 2 to 30% by weight.
% By weight is preferred.

As the binder, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene butadiene rubber (SBR), fluoro rubber, carboxy Thermoplastic resins such as methylcellulose, methylcellulose (MC), and polyvinyl alcohol (PVA), polymers having rubber elasticity, polysaccharides, and the like can be used as one kind or as a mixture of two or more kinds. Further, it is preferable that a binding agent having a functional group that reacts with lithium, such as a polysaccharide, be deactivated by performing a treatment such as methylation. The addition amount is preferably 1 to 50% by weight, particularly preferably 2 to 30% by weight.

As the filler, any material may be used as long as it does not adversely affect battery performance. Usually, olefin polymers such as polypropylene and polyethylene, amorphous silica, alumina, zeolite, glass, carbon and the like are used. The addition amount of the filler is preferably 0 to 30% by weight.

As the current collector of the active material, any collector may be used as long as it does not adversely affect the constructed battery. For example, as a material of the positive electrode current collector, in addition to aluminum, titanium, stainless steel, nickel, calcined carbon, conductive polymer, conductive glass, and the like, for the purpose of improving adhesion, conductivity, and oxidation resistance, A material obtained by treating the surface of aluminum, copper, or the like with carbon, nickel, titanium, silver, or the like can be used. As the material of the negative electrode current collector, in addition to copper, stainless steel, nickel, aluminum, titanium, calcined carbon, conductive polymer, conductive glass, Al-Cd alloy, and the like,
For the purpose of improving adhesion, conductivity, and oxidation resistance, a material obtained by treating the surface of copper or the like with carbon, nickel, titanium, silver, or the like can be used. These materials can be oxidized on the surface. As these shapes, in addition to the foil shape, a film shape, a sheet shape, a net shape, a punched or expanded shape, a lath body, a porous body, a foamed body, a formed body of a fiber group, and the like are used. The thickness is not particularly limited, but a thickness of about 1 to 500 μm is used.

As the separator, an insulating thin film having excellent ion permeability and mechanical strength can be used. Olefin polymers such as polypropylene and polyethylene, glass fiber, and organic solvent resistant and hydrophobic
Sheets, microporous membranes, and nonwoven fabrics made of polyvinylidene fluoride, polytetrafluoroethylene, or the like are used.
The pore size of the separator is in a range generally used for a battery, and is, for example, 0.01 to 10 μm. The same applies to the thickness, which is in the range generally used for batteries, for example, 5 to 300 μm.

As the electrolyte, for example, an organic electrolyte, a polymer solid electrolyte, an inorganic solid electrolyte, a molten salt, an aqueous alkaline electrolyte and the like can be used.

As described in claim 2, when the lithium ion is involved in the electrode reaction, the phase A capable of electrochemically storing and releasing lithium may be, for example, lithium, tin, silicon or these. And the like containing the above element are preferred. The charge / discharge reaction of an alloy containing these elements proceeds at a potential very close to the potential of metallic lithium, which is about 0.1 V with respect to the potential of metallic lithium. On the other hand, as the B phase which has electron conductivity and is electrochemically inactive in the charge / discharge potential range, particularly a metal containing at least one or more common elements with the A phase, an intermetallic compound or a solid solution Although not limited, in particular, any one of lithium, tin, silicon contained in the A phase and any of the elements contained in the alloy thereof and the metal element or the metalloid element belonging to Group 2 to Group 16 of the periodic table. An alloy with at least one kind that cannot electrochemically occlude and release lithium can be suitably used.

For example, a solid solution of silicon and a group 3 element;
And an alloy of silicon alone. The solid solution of silicon and the group 3 element has excellent electron conductivity, but hardly alloys with lithium. Further, since the solid solution contains silicon, it is possible to form an alloy with silicon alone with an arbitrary composition. When lithium is occluded in an alloy of such a solid solution of silicon and a Group 3 element and silicon alone,
Although alloying with lithium proceeds with respect to simple substance of silicon, the solid solution of silicon and the group 3 element is maintained with electron conductivity. That is, a large matrix having electron conductivity formed of a solid solution of silicon and a Group 3 element is formed in the alloy, and the single silicon in the matrix absorbs and releases lithium, whereby a charge / discharge reaction proceeds. Therefore, it is considered that phenomena such as crystal collapse, pulverization, or falling off are suppressed, and an overvoltage accompanying occlusion / release of lithium is reduced. Furthermore, since the charge / discharge reaction in this case proceeds at a potential very close to the potential of metallic lithium, which is about 0.1 V with respect to the potential of metallic lithium,
A high capacity is obtained as a negative electrode for a lithium battery, and the electrode material is excellent in reversibility.

The elements of Group 3 of the periodic table referred to herein are:
Sc, Y, lanthanoid elements (La, Ce, Pr, N
d, Pm, Sm, Eu, Gd, Tb, Dy, Ho, E
r, Tm, Yb, Lu), actinoid elements (Ac, T
h, Pa, U, Np, Pu, Am, Cm, Bk, Cf,
Es, Fm, Md, No, Lr). Of these, S
c: scandium, Y: yttrium, La: lanthanum, Ce: cerium, Pr: praseodymium, and Nd: neodymium are preferable since excellent battery characteristics can be obtained, but are not limited thereto.

When such an alloy is used as a negative electrode material, MnO ₂ , MoO ₃ , V ₂ O ₅ ,
Metal oxides such as Li _x CoO ₂ , Li _x NiO ₂ , Li _x Mn ₂ O ₄ , and metal chalcogenides such as TiS ₂ , MoS ₂ and NbSe ₃ , and graphite layers such as polyacene, polyparaphenylene, polypyrrole, and polyaniline Compound,
Also, various substances capable of absorbing and releasing an alkali metal ion and an anion such as a conductive polymer can be used.

In particular, from the viewpoint of high energy density, V
₂ O ₅ , MnO ₂ , Li _x CoO ₂ , Li _x NiO ₂ , Li _x M
having an electrode potential of 3~4V such n ₂ O ₄ are preferred. Particularly, Li _x CoO ₂ , Li _x NiO ₂ , Li _x Mn ₂ O ₄
Etc. are preferred.

On the other hand, when such an alloy is used as a positive electrode active material, the negative electrode material may be a lithium metal, a lithium alloy, a carbonaceous material capable of inserting and extracting lithium ions or lithium metal, a chalcogen compound, and lithium such as methyllithium. Organic compounds containing Further, by using the alloy in combination with lithium metal or a lithium alloy or an organic compound containing lithium, lithium can be inserted into the A-phase portion inside the battery.

It is preferable to use an organic electrolytic solution for the electrolyte. Examples of the organic solvent of the organic electrolyte include propylene carbonate, ethylene carbonate, butylene carbonate, diethyl carbonate, dimethyl carbonate, methyl ethyl carbonate, esters such as γ-butyrolactone, tetrahydrofuran, substituted tetrahydrofuran such as 2-methyltetrahydrofuran, and dioxolane. , Diethyl ether, dimethoxyethane, diethoxyethane, ethers such as methoxyethoxyethane, dimethyl sulfoxide, sulfolane, methyl sulfolane, acetonitrile, methyl formate, methyl acetate, N-
Methylpyrrolidone, dimethylformamide and the like can be mentioned, and these can be used alone or as a mixed solvent. Examples of the supporting electrolyte salt, LiClO _4, LiP
F ₆ , LiBF ₄ , LiAsF ₆ , LiCF ₃ SO ₃ , Li
N (CF ₃ SO ₂ ) ₂ , LiN (C ₂ F ₅ SO ₂ ) ₂ , LiN
(CF ₃ SO ₂ ) (C ₄ F ₉ SO ₂ ) and the like, and these can be used alone or as a mixed salt. On the other hand, as the polymer solid electrolyte, a material obtained by dissolving the above-mentioned supporting electrolyte salt in a polymer such as polyethylene oxide or a crosslinked product thereof, or polyphosphazene or a crosslinked product thereof can be used. Further, inorganic solid electrolytes such as Li ₃ N and LiI can be used. That is, any non-aqueous electrolyte having lithium ion conductivity may be used.

In the case where hydroxide ions are involved in the electrode reaction, the A phase capable of electrochemically storing and releasing hydrogen may be, for example, LaN.
i ₅ and MmNi ₅ (where Mm is a part of La, Ce,
A misch metal substituted with Pr, Nd or other rare earth elements), an AB5-type alloy in which Ni is substituted with a metal element such as Al, Co, Mn, a Ti-Mn alloy, a Ti-
AB2 type alloys such as V alloys, A2B type alloys such as Mg-Ni alloys, and alloys in which some of the constituent elements of these alloys are replaced with other metal elements are preferable. The charge / discharge reaction of these alloys proceeds at a potential very close to the hydrogen potential of about 0.1 V with respect to the standard hydrogen electrode potential. On the other hand, it has electronic conductivity,
The B phase which is electrochemically inactive in the charge / discharge potential range is not particularly limited as long as it is a metal, an intermetallic compound or a solid solution containing at least one or more common elements with the A phase. A single element of any of the elements contained in the A phase, or at least one of a metal element or a metalloid element belonging to Group 2 to Group 16 of the periodic table, and Alloys that cannot electrochemically occlude and release hydrogen can be suitably used.

[0037] For _{example, Mm 1.0 Ni 4.0 Co 0.5 Mn} 0.2 A
A solid solution of an AB5 type alloy having a composition represented by l _0.3 and nickel alone can be used. Nickel alone is excellent in electron conductivity, but hardly hydrogenates. Mm _1.0 Ni
_4.0 Co _0.5 Mn _0.2 Al _0.3 because containing nickel, it is possible to form the elemental nickel and an alloy of any composition. Such Mm _1.0 Ni _4.0 Co _0.5 Mn _0.2 Al _0.3
When hydrogen is occluded in an alloy of an AB5 type alloy having the composition represented by the following formula and nickel alone, hydrogenation of the AB5 type alloy portion proceeds, but the nickel single portion is maintained with electron conductivity. That is, a large matrix having electron conductivity composed of nickel alone is formed in the alloy, and the AB5 type alloy in the matrix absorbs and releases hydrogen, so that a charge / discharge reaction proceeds. It is considered that phenomena such as pulverization or falling off are suppressed, and the overvoltage caused by occlusion / release of hydrogen is reduced.

When such an alloy is used as a negative electrode material, Ni (OH) ₂ can be suitably used as a positive electrode active material.

As the electrolyte, an aqueous alkaline electrolyte can be suitably used. Solutes used in the aqueous alkaline electrolyte include KOH, NaOH, LiOH
These can be used alone or as a mixture, but it is particularly preferable to use at least KOH.

[0040]

Embodiments of the present invention will be described below.

Example 1 Cerium and silicon were mixed at a weight ratio of 57:43 (elemental ratio: 13:87) and heated to 1620 ° C. in an argon atmosphere using an induction furnace.
After cooling, the obtained substance was pulverized in a mortar to obtain a powder.
The X-ray diffraction pattern of this powder is shown in FIG. In FIG.
(A) is the X-ray diffraction pattern of silicon powder, (b) is the X-ray diffraction pattern of the reagent CeSi ₂ , and (c) is the X-ray diffraction pattern of the substance obtained in this example. As is clear from FIG. 1, the substance obtained above was found to be an alloy of silicon and cerium silicide.

In order to examine the possibility of occlusion of lithium in the alloy, 100 mg of the alloy was sandwiched between two nickel meshes of 10 mm × 10 mm, and a lead wire was attached.
Working electrode for terminal cell. The following operations were performed in dry air, and all the materials were used after sufficiently drying in advance. As the counter electrode and the reference electrode, metallic lithium of an appropriate size was used by pressing on a nickel plate. LiCl
A three-terminal cell (A) was produced using a propylene carbonate solution in which O ₄ was dissolved at a concentration of 1 mol / liter as an electrolyte.

For comparison, the alloy was replaced by granular silicon
A three-terminal cell (B) was produced in the same manner as in Example 1 except that 100 mg was used.

Each of the working electrodes of the three-terminal cell (A) and the three-terminal cell (B) has a current of 1 mA between the working electrode and the counter electrode.
The current of 0.005 to 0.005
Cyclic voltammogram (CV) measurements were taken which varied repeatedly in the range of 2.00 V.

As a result, insertion and extraction of lithium were confirmed in the three-terminal cell (A), and the reversible capacity was 800 mAh.
/ G. On the other hand, in the three-terminal cell (B), almost no lithium was inserted and extracted, and lithium was observed to be deposited on the working electrode. As is evident from the results, it is expected that when the alloy of silicon and the silicon-group III element alloy according to the present invention is used as a negative electrode material, a battery having excellent charge / discharge cycle properties and a high capacity can be provided.

The alloy was further pulverized in a mortar to produce a coin-type lithium secondary battery shown in FIG. 3 as follows. The pulverized alloy, acetylene black and polytetrafluoroethylene powder were mixed at a weight ratio of 85: 10: 5, and toluene was added and kneaded sufficiently to obtain a clay-like paste. The paste was formed into a sheet having a thickness of 0.3 mm by a roller press. The sheet was punched into a circle having a diameter of 16 mm, and heat-treated at 200 ° C. under reduced pressure for 15 hours to obtain a negative electrode 2. The negative electrode 2 was used by being pressed against a negative electrode can 5 provided with a negative electrode current collector 7.

The positive electrode was prepared by mixing LiCoO ₂ , acetylene black and polytetrafluoroethylene powder at a weight ratio of 85:
The mixture was mixed at a ratio of 10: 5, and toluene was added and kneaded sufficiently to obtain a clay-like paste. This was formed into a sheet having a thickness of 0.8 mm by a roller press. The sheet was punched into a circle having a diameter of 16 mm,
Heat treatment was performed for 5 hours to obtain a positive electrode 1. The positive electrode 1 is a positive electrode current collector 6
The positive electrode can 4 was pressed and used.

The electrolytic solution was prepared by adding LiPF to a mixed solvent of ethylene carbonate and diethyl carbonate at a volume ratio of 1: 1.
₆ was dissolved at a concentration of 1 mol / liter. As the separator 3, a microporous film made of polypropylene was used. Using the positive electrode 1, the negative electrode 2, the electrolytic solution and the separator 3, a coin-type lithium battery having a diameter of 20 mm and a thickness of 1.6 mm was produced. 8 is an insulating packing.

A charge / discharge cycle test was conducted using a large number of the coin type lithium batteries. The test condition was a charging current of 3 m
A, the charge end voltage was 4.2 V, the discharge current was 3 mA, and the discharge end voltage was 3.0 V. As a result, it was found that the capacity was maintained at 80% or more of the initial capacity even after 200 cycles.

From the above results, when an alloy of silicon and a silicon-3 group element alloy is used as a negative electrode material, a high capacity is obtained.
It was found that a lithium secondary battery having excellent cycle characteristics could be provided. (Example _{2) Mm 1.0 Ni 4.0 Co 0.5} M
A hydrogen storage alloy having a composition of n _0.2 Al _0.3 and nickel were mixed at a weight ratio of 80:20, and heated to 1050 ° C. in an argon atmosphere using an induction furnace. After cooling, the obtained substance was pulverized in a mortar so as to have an average particle size of 40 μm to obtain a powder. The X-ray diffraction pattern of this powder is shown in FIG.
2A is an X-ray diffraction diagram of the nickel powder, FIG. 2B is an X-ray diffraction diagram of the hydrogen storage alloy having the composition of Mm _1.0 Ni _4.0 Co _0.5 Mn _0.2 Al _0.3 , and FIG. FIG. 3 is an X-ray diffraction diagram of the substance obtained in the example. As is clear from FIG. 2, it was found that the substance obtained in this example was an alloy of the hydrogen storage alloy and nickel.

Using this alloy, a nickel-metal hydride battery was prototyped as follows. The alloy powder and methylcellulose 2
% Aqueous solution at a weight ratio of 75:25 and kneaded well.
The paste was used. The paste was uniformly filled in a foamed nickel porous body, dried at 80 ° C., and then press-molded by a roller press to obtain a negative electrode 2.

As the positive electrode 1, a sintered Ni (OH) ₂ electrode manufactured by a known method was used. 6 mo of KOH in water
An electrolytic solution dissolved at a concentration of 1 / liter was used, and a polypropylene nonwoven fabric was used for the separator 3. The positive electrode,
The negative electrode, the electrolytic solution, and the separator were spirally wound to produce an AA-size cylindrical nickel-metal hydride battery.

A charge / discharge cycle test was performed using the battery thus manufactured. The test conditions were a charging current of 130
0 mA, charge time 1.15 hours, discharge current 1300 m
A, the discharge end voltage was 1.0 V. As a result of a charge / discharge test of these manufactured batteries, it was found that the capacity of 80% or more was maintained even after 800 cycles.

In Example 1, a lithium battery was taken as an example, and the performance as a negative electrode active material was particularly shown. Example 2
In the above, a nickel-metal hydride battery was taken as an example, and the performance as a negative electrode active material was particularly shown. The present invention is not limited to the starting materials, the production method, the positive electrode, the negative electrode, the electrolyte, the separator, the battery shape, and the like of the active material described in the above examples.

[0055]

As described above, the present invention provides an electrode material which has a small change in crystal system and volume during charging and discharging, can be charged and discharged reversibly, and has high electron conductivity. Therefore, it is possible to provide a battery exhibiting excellent charge / discharge cycle performance at a high voltage, a high capacity and a high energy density, and having excellent safety.

[Brief description of the drawings]

FIG. 1 is an X-ray diffraction diagram of an alloy used for a battery of the present invention.

FIG. 2 is an X-ray diffraction diagram of the alloy used in the battery of the present invention.

FIG. 3 is a sectional view of the battery of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 positive electrode 2 negative electrode 3 separator 4 positive electrode can 5 negative electrode can 6 positive electrode current collector 7 negative electrode current collector 8 insulating packing

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Toshiyuki Natsuta 2-3-1, Furube-cho, Takatsuki-shi, Osaka F-term in Yuasa Corporation 5H029 AJ02 AJ05 AK11 AL11 AM03 AM04 AM05 AM07 BJ03 BJ16 DJ16 DJ17 5H050 AA02 AA07 BA17 CA17 CB11 EA10 EA24 FA17 FA18

Claims (3)

[Claims] 1. A battery comprising a positive electrode, a negative electrode, and an electrolyte, wherein at least one of the positive electrode and the negative electrode contains an alloy, and the alloy comprises an alloy of an A phase and a B phase. And the B phase contains at least one or more common elements, the A phase is made of a metal, an intermetallic compound or a solid solution capable of reversibly charging and discharging in the battery, and the B phase is an electron conductive material. And comprising a metal, an intermetallic compound, or a solid solution that is electrochemically inactive in the battery in the charge / discharge potential range of the battery. 2. The method according to claim 1, wherein the charge / discharge reaction is a reaction in which lithium ions participate in an electrode reaction, and the phase A is capable of electrochemically storing and releasing lithium. battery. 3. The charge / discharge reaction in which hydroxide ions participate in an electrode reaction, and the A-phase is capable of electrochemically storing and releasing hydrogen. The battery as described.