JP2003282053A - Negative electrode material for non-aqueous electrolyte cell, negative electrode, and non-aqueous electrolyte cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a negative-electrode material for non-aqueous electrolyte cells, which has excellent discharge capacity, an outstanding cycle life, and good discharge rate characteristics, and in which the maximum capacity can be reached by the minimum number of times of electricity charging/discharging. <P>SOLUTION: The negative-electrode material has a composition expressed by a formula of A<SB>a</SB>M<SB>b</SB>T<SB>c</SB>X<SB>d</SB>Z<SB>e</SB>, and includes an alloy which consists of an amorphous phase substantially. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a negative electrode material for a non-aqueous electrolyte battery, a negative electrode containing the negative electrode material, and a non-aqueous electrolyte battery including the negative electrode (including a primary battery and a secondary battery).

[0002]

2. Description of the Related Art In recent years, a non-aqueous electrolyte battery using metallic lithium as a negative electrode active material has attracted attention as a high energy density battery, and manganese dioxide (Mn 2
O ₂ ), fluorocarbon [(CF ₂ ) n], thionyl chloride (S
A primary battery using OC1 ₂ ) or the like is already widely used as a power source for calculators and watches and a backup battery for memories. Further, with the recent miniaturization and weight reduction of various electronic devices such as VTRs and communication devices, the demand for high energy density secondary batteries as their power source has increased, and research on lithium secondary batteries using lithium as a negative electrode active material has been conducted. It is active.

As a lithium secondary battery, a negative electrode containing metallic lithium, propylene carbonate (PC), 1,2-dimethoxyethane (DME), γ-butyrolactone (γ-B).
L), a non-aqueous electrolyte such as LiClO ₄ , LiBF ₄ , and LiAsF _{6 in} a non-aqueous solvent such as tetrahydrofuran (THF) or an electrolyte composed of a lithium conductive solid electrolyte and a topochemical between lithium. Compounds that react (eg TiS ₂ , MoS ₂ , V ₂
Those having a positive electrode containing O ₅ , V ₆ O ₁₃ , MnO _2, etc.) as a positive electrode active material have been studied.

However, the lithium secondary battery described above has not yet been put into practical use. The main reason for this is that the metallic lithium used for the negative electrode becomes fine powder during repeated charging and discharging, and becomes reactive dendrites, which impairs the safety of the battery and also causes damage to the battery, short circuit, and thermal runaway. This is because it may cause it. In addition, there is a problem that deterioration of lithium metal lowers charge / discharge efficiency and shortens cycle life.

In view of the above, it has been proposed to use a carbonaceous material that absorbs and releases lithium, such as coke, a resin fired body, carbon fiber, and pyrolytic vapor phase carbon, instead of metallic lithium. In recent years, commercialized lithium ion secondary batteries include a negative electrode containing a carbonaceous material and LiCoO 2.
It is provided with a positive electrode containing ₂ and a non-aqueous electrolyte. In such a lithium ion secondary battery, a reaction occurs in which lithium ions released from the negative electrode are taken into the non-aqueous electrolyte during discharging, and lithium ions in the non-aqueous electrolyte are occluded in the positive electrode during charging.

By the way, due to recent demands for further miniaturization of electronic equipment and continuous use for a long time, there is a strong demand for further improvement of battery capacity. However,
With conventional carbon materials, there is a limit to the improvement of charge and discharge capacity,
In addition, since low-temperature fired carbon, which is considered to have a high capacity, has a low material density, it is difficult to increase the charge / discharge capacity per unit volume. Therefore, it is necessary to develop new negative electrode materials to realize high capacity batteries.

In view of this, Japanese Unexamined Patent Publication No. 2000-311681 discloses that amorphous Sn.
It is disclosed that a negative electrode material for a lithium secondary battery containing particles containing an A.X alloy as a main component is used. In the above formula, A represents at least one kind of transition metal, X represents O,
F, N, Mg, Ba, Sr, Ca, La, Ce, Si,
Ge, C, P, B, Bi, Sb, Al, In, S, S
At least one selected from the group consisting of e, Te and Zn is shown. However, X may not be contained. Further, in the number of atoms of each atom in the above formula, Sn / (Sn +
A + X) = 20 to 80 atomic%.

However, the electrode material containing the particles having the non-stoichiometric composition of the amorphous Sn.A.X alloy as the main component is inferior in the diffusion rate of lithium, so that high rate characteristics cannot be obtained. There is a problem.

Further, in an alloy system in which Sn is a basic element having a Li occlusion capacity as in Japanese Patent Laid-Open No. 2000-311681, when the Sn content is as small as 20 atomic% or less, not only the rate characteristics are poor but also a high capacity is obtained. You won't get it. In fact, Table 1 shows that the amorphous alloy whose composition is represented by Sn ₁₈ Co ₈₂ has a higher initial charge / discharge efficiency, discharge capacity and cycle life than the fine crystalline alloy having a Sn content of 20 to 80 atomic%. Is shown to be inferior.

[0010]

DISCLOSURE OF THE INVENTION The present invention has excellent discharge capacity, cycle life and discharge rate characteristics, and further reaches the maximum capacity with the minimum number of times of charge and discharge, a negative electrode material for a non-aqueous electrolyte battery, a negative electrode and a non-aqueous electrolyte battery. It is intended to provide a water electrolyte battery.

[0011]

The first negative electrode material for a non-aqueous electrolyte battery according to the present invention contains an alloy having a composition represented by the following general formula (1) and substantially consisting of an amorphous phase. It is characterized by that.

A _a M _b T _c X _d Z _e (1) wherein A is one or more elements selected from the group consisting of Ca, Sr and Ba, or the elements and other alkaline earth metals. And M is at least one element selected from the group consisting of Ni and Cu, and T is Si, Al, In, Ge, P, Pb, Bi, S.
one or more elements selected from the group consisting of b, Zn, Ga and C, and X is Fe, Co, Mn, Cr, T
i, V, Zr, Nb, Hf, Ta, Mo, W and one or more elements selected from the group consisting of rare earth elements, Z is one or more elements selected from the group consisting of O, C, H and N And a, b, c, d, and e are a + b +
c + d + e = 100 atom%, 30 ≦ a ≦ 80, 20 ≦ b
≦ 70, 0 ≦ c ≦ 40, 0 ≦ d ≦ 20, and 0 ≦ e ≦ 20 are satisfied.

A second negative electrode material for a non-aqueous electrolyte battery according to the present invention is characterized by containing an alloy having a composition represented by the following general formula (2) and having a substantially amorphous phase. Is.

[A _a M _b T _c X _d Z _e ] _x Li _y (2) wherein A is at least one element selected from the group consisting of Ca, Sr and Ba, or the above elements and other elements. M is at least one element selected from the group consisting of Ni and Cu, and T is Si, Al, In, Ge, P, Pb, Bi, S.
one or more elements selected from the group consisting of b, Zn, Ga and C, and X is Fe, Co, Mn, Cr, T
i, V, Zr, Nb, Hf, Ta, Mo, W and one or more elements selected from the group consisting of rare earth elements, Z is one or more elements selected from the group consisting of O, C, H and N And the atomic ratios a, b, c, d, e, x and y
Is a + b + c + d + e = 1, x + y = 100 atom%,
0.3 ≦ a ≦ 0.8, 0.2 ≦ b ≦ 0.7, 0 ≦ c ≦
0.4, 0 ≦ d ≦ 0.2, 0 ≦ e ≦ 0.2, 0 <y ≦ 3
0 is satisfied respectively.

A third negative electrode material for a non-aqueous electrolyte battery according to the present invention comprises an alloy having a composition represented by the following general formula (3) and containing a fine crystalline phase having an average crystal grain size of 500 nm or less. It is characterized by including.

A _a M _b T _c X _d Z _e (3) wherein A is one or more elements selected from the group consisting of Ca, Sr and Ba, or the elements and other alkaline earth metals. And M is at least one element selected from the group consisting of Ni and Cu, and T is Si, Al, In, Ge, P, Pb, Bi, S.
one or more elements selected from the group consisting of b, Zn, Ga and C, and X is Fe, Co, Mn, Cr, T
i, V, Zr, Nb, Hf, Ta, Mo, W and one or more elements selected from the group consisting of rare earth elements, Z is one or more elements selected from the group consisting of O, C, H and N And a, b, c, d and e are a + b + c +
d + e = 100 atom%, 20 ≦ a ≦ 85, 15 ≦ b ≦ 8
0, 0 ≦ c ≦ 40, 0 ≦ d ≦ 20, and 0 ≦ e ≦ 20 are satisfied.

A fourth negative electrode material for a non-aqueous electrolyte battery according to the present invention is an alloy having a composition represented by the following general formula (4) and containing a fine crystal phase having an average crystal grain size of 500 nm or less. It is characterized by including.

[A _a M _b T _c X _d ] _x Li _y (4) where A is one or more elements selected from the group consisting of Ca, Sr and Ba, or the elements and other alkalis. And M is one or more elements selected from the group consisting of Ni and Cu, and T is Si, Al, In, Ge, P, Pb, Bi, S.
one or more elements selected from the group consisting of b, Zn, Ga and C, and X is Fe, Co, Mn, Cr, T
i, V, Zr, Nb, Hf, Ta, Mo, W and one or more elements selected from the group consisting of rare earth elements, Z is one or more elements selected from the group consisting of O, C, H and N And the atomic ratios a, b, c, d, e, x and y are
a + b + c + d + e = 1, x + y = 100 atom%, 0.
2 ≦ a ≦ 0.85, 0.15 ≦ b ≦ 0.8, 0 ≦ c ≦
0.4, 0 ≦ d ≦ 0.2, 0 ≦ e ≦ 0.2, 0 <y ≦ 3
0 is satisfied respectively.

The negative electrode according to the present invention has the above-mentioned first to fourth parts.
Among the negative electrode materials for non-aqueous electrolyte batteries of No. 1, at least one kind is contained.

The non-aqueous electrolyte battery according to the present invention comprises a negative electrode containing at least one of the above-mentioned first to fourth negative electrode materials for non-aqueous electrolyte batteries, a positive electrode, and a non-aqueous electrolyte. It is a feature.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION First, the first to fourth negative electrode materials for non-aqueous electrolyte batteries according to the present invention will be described.

<First Anode Material for Non-Aqueous Electrolyte Battery> The first anode material for a non-aqueous electrolyte battery according to the present invention has a composition represented by the following general formula (1) and is substantially amorphous. Includes alloys of phases.

A _a M _b T _c X _d Z _e (1) where A is one or more elements selected from the group consisting of Ca, Sr and Ba, or the above elements and other alkaline earth metals. And M is at least one element selected from the group consisting of Ni and Cu, and T is Si, Al, In, Ge, P, Pb, Bi, S.
one or more elements selected from the group consisting of b, Zn, Ga and C, and X is Fe, Co, Mn, Cr, T
i, V, Zr, Nb, Hf, Ta, Mo, W and at least one element selected from the group consisting of rare earth elements, and Z is at least one or more element selected from the group consisting of O, C, H and N. In the element, a, b, c, d and e are a
+ B + c + d + e = 100 atom%, 30 ≦ a ≦ 80, 2
0 ≦ b ≦ 70, 0 ≦ c ≦ 40, 0 ≦ d ≦ 20, 0 ≦ e ≦
Satisfy each 20.

Examples of the metallographic structure substantially consisting of an amorphous phase include those which do not show a peak based on the crystalline phase in X-ray diffraction.

(Alkaline Earth Metal Element A) The alkaline earth metal element A contains at least one element selected from the group consisting of Ca, Sr and Ba as an essential component. The element A has a function of facilitating occlusion / release of lithium. The atomic ratio a of the element A is 30 to 8
The reason for limiting the content within the range of 0 atomic% is for the reason described below. If the atomic ratio a of the element A is less than 30 atomic%, the lithium absorption / desorption rate decreases,
It becomes difficult to improve the discharge rate characteristics of the non-aqueous electrolyte battery. On the other hand, when the atomic ratio a of the element A exceeds 80 atomic%, the amount of retained lithium in the alloy increases, so that the discharge capacity significantly decreases as the non-aqueous electrolyte battery is charged and discharged. A more preferable range of the atomic ratio a is 35.
~ 75 atom%.

Among the alkaline earth metal elements A, preferable ones include Sr and Ca as essential elements, Ba and Ca as essential elements, Sr and Ba as essential elements, and Ca and Sr.
3 and Ba are essential components. C
The proportion of the essential component consisting of one or more elements selected from the group consisting of a, Sr and Ba should be 50 atomic% or more when the atomic ratio of the alkaline earth metal element A is 100 atomic%. desirable. This is because if the ratio is less than 50 atom%, the discharge rate characteristic may not be sufficiently improved. It is preferably at least 60 atom%.

Mg is preferable as the other alkaline earth metal element A used in combination with Ca, Sr and Ba.

(Element M) By combining the element M with the alkaline earth metal element A, the amorphization can be promoted. Further, the element M can suppress pulverization when lithium is occluded and released in the negative electrode material.
The atomic ratio b of the element M is limited to the range of 20 to 70 atomic% for the following reason. When the atomic ratio b is out of the above range, it becomes difficult to make it amorphous. A more preferable range of the atomic ratio b of the element M is 25 to 65 atom%.
Is.

In particular, it is desirable to use Cu as the element M. With such a structure, the amorphization of the alloy can be promoted, and the average interplanar spacing of the amorphous phase obtained by X-ray diffraction is 3Å.
It becomes possible to do above.

(Element T) Element T is an element capable of alloying with lithium. Therefore, by containing the element T in the negative electrode material, the amount of lithium stored can be increased, and the capacity of the non-aqueous electrolyte battery can be improved. Further, addition of T makes it easier to obtain an amorphous phase more stably. However, when the atomic ratio c of the element T exceeds 40 atomic%, it becomes almost difficult to make it amorphous. Therefore, the atomic ratio c of the element T is preferably 40 atomic% or less, and more preferably 35 atomic% or less. If the atomic ratio c is less than 2 atomic%, the effect of improving the battery capacity may not be obtained.
The lower limit of the atomic ratio c is preferably 2 atomic%.

Among the elements T, Si, In and Al are preferable.

(Element X) As the rare earth element, for example,
La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, T
Examples thereof include b, Dy, Ho, Er, Tm, Yb and Lu. Among them, La, Ce, Pr, Nd and Sm are preferable.

Amorphization can be promoted by containing the element X in an atomic ratio of 20 atomic% or less. In addition, the retention of the stored Li in the alloy is reduced,
It is also effective in suppressing the capacity decrease due to charge and discharge.

(Element Z) The element Z is at least one element selected from the group consisting of O, C, H and N.
These elements are elements that work effectively for amorphization, but depending on the manufacturing process and amount, they may form oxides, carbides, hydrides, and nitrides to form multiple phases, but there is a problem with electrode characteristics. There is no. If the amount e exceeds 20 atom%, the capacity decreases, so the amount e is made 20 atom% or less.
It is preferably 15 atomic% or less.

Examples of the metallographic structure substantially consisting of an amorphous phase include those having no peak based on the crystalline phase in X-ray diffraction. here,
The average interplanar spacing determined from the strongest peaks appearing on the low-angle side of the broad diffraction line in X-ray diffraction does not form a crystal lattice in the amorphous phase, so there is no set interplanar spacing between diffraction planes. The distance is d. The average surface spacing d is 2 dsin θ = λ (λ
= 1.5418Å, 2θ: diffraction angle).

In an alloy consisting essentially of an amorphous phase, the atomic arrangement has no regularity, and if the average interplanar spacing obtained from the strongest diffraction peak in X-ray diffraction is less than 3Å, the diffusion rate of lithium decreases, It may be difficult to reach the original capacity, the number of charge / discharge cycles until reaching the maximum capacity may increase, and the discharge rate characteristics may not be sufficiently improved. The diffusion rate of lithium can be improved by increasing the average interplanar spacing obtained from the strongest diffraction peak of the alloy consisting of the substantially amorphous phase to 3 Å or more, thereby improving the discharge rate characteristics of the non-aqueous electrolyte battery. be able to. However, if the average interplanar spacing is larger than 4.5 Å, it becomes difficult for Li to be occluded in a stable manner, and the charge / discharge capacity may decrease.
Therefore, it is more preferable that the average surface distance is 3 Å or more and 4.5 Å or less. A more preferable range of the average surface spacing is 3.3 to 4Å.

Since the first negative electrode material for a non-aqueous electrolyte battery according to the present invention described above is relatively easy for lithium ions or lithium atoms to move in and out, the discharge when the discharge rate of the non-aqueous electrolyte battery is increased. The decrease in capacity can be suppressed, that is, the discharge rate characteristic can be improved. Moreover, the number of times of charging and discharging to reach the maximum capacity can be reduced. Further, since the volume expansion / contraction ratio due to lithium ions or lithium atoms coming in and out can be reduced, the capacity deterioration due to pulverization can be reduced, and the charge / discharge cycle life of the secondary battery can be improved.

According to the present invention, the following (I) and (II) are mentioned as one of the causes for facilitating the entry and exit of lithium ions or lithium atoms.

(I) Sr and Ba are SrLi ₄ and BaL in which four Li atoms are bonded to one Sr or Ba atom.
i ₄ can be formed and high capacity is achieved. On the other hand, when Ca is less than Sr and Ba in terms of capacity, it is preferable from the viewpoint of cycle life.

(II) Since Ca, Sr and Ba have larger atomic radii than Mg and Be, which are the same alkaline earth elements, the composition represented by the above-mentioned formula (1) is used to obtain X-rays. The average interplanar spacing due to diffraction can be increased.

In the first negative electrode material for a non-aqueous electrolyte battery according to the present invention, the average interplanar spacing by X-ray diffraction is 3
By making it Å or more, the number of charge and discharge cycles required to reach the maximum capacity can be reduced and the discharge rate characteristic can be improved.

Further, in the first negative electrode material for a non-aqueous electrolyte battery according to the present invention, since the alloying element does not contain lithium, the element is easily handled during the synthesis of the negative electrode material, and the liquid quenching method is used. There is no risk of ignition when synthesizing the negative electrode material, and mass production is easy. Further, in the alloy system containing no lithium, the activation energy from the non-equilibrium phase to the stable phase is high, so that the amorphous phase itself is stable.
Therefore, it is advantageous for the charge / discharge cycle life of the electrode characteristics. Further, the manufacturing yield of the negative electrode material can be increased because it is unlikely to be affected by fluctuations in heat treatment conditions.

<Second Anode Material for Non-Aqueous Electrolyte Battery> The second anode material for a non-aqueous electrolyte battery according to the present invention has a composition represented by the following general formula (2) and is substantially amorphous. Includes alloys of phases.

[A _a M _b T _c X _d Z _e ] _x Li _y (2) where A is one or more elements selected from the group consisting of Ca, Sr and Ba, or the above elements and other elements. M is at least one element selected from the group consisting of Ni and Cu, and T is Si, Al, In, Ge, P, Pb, Bi, S.
one or more elements selected from the group consisting of b, Zn, Ga and C, and X is Fe, Co, Mn, Cr, T
i, V, Zr, Nb, Hf, Ta, Mo, W and one or more elements selected from the group consisting of rare earth elements, Z is one or more elements selected from the group consisting of O, C, H and N And the atomic ratios a, b, c, d, e, x and y are
a + b + c + d + e = 1, x + y = 100 atom%, 0.
3 ≦ a ≦ 0.8, 0.2 ≦ b ≦ 0.7, 0 ≦ c ≦ 0.
4, 0 ≦ d ≦ 0.2, 0 ≦ e ≦ 0.2, and 0 <y ≦ 30 are satisfied.

The negative electrode material for the second non-aqueous electrolyte battery is
Lithium is included in the constituents, and the atomic ratio a,
Except that the total of b, c, d, and e is set to 1, it has the same structure as the above-mentioned first negative electrode material for a non-aqueous electrolyte battery.

The atomic ratio y of lithium will be described below.

(Li) Lithium is an element responsible for charge transfer in the non-aqueous electrolyte battery. For this reason, when lithium is contained as an alloy constituent element, the amount of lithium stored / released in the negative electrode can be improved, and the battery capacity and charge / discharge cycle life can be improved. Further, since the second negative electrode material is more easily activated than the first negative electrode material, the maximum discharge capacity can be obtained relatively early in the charge / discharge cycle.

By the way, when lithium is not contained as a constituent element like the first negative electrode material, it is necessary to use a lithium-containing compound such as a lithium composite metal oxide for the positive electrode active material. According to the second negative electrode material, a compound containing no lithium as a constituent element can be used as a positive electrode active material, and the types of usable positive electrode active materials can be expanded. However, if the lithium content z exceeds 30 atomic%, it becomes difficult to make amorphous and the charge / discharge cycle life of the secondary battery is shortened.

The first and second negative electrode materials are produced, for example, by a casting method, a liquid quenching method, a gas atomizing method, a rotating disk method.

(Casting Method) The first and second negative electrode materials are obtained by blending each element so as to have a predetermined composition and then melting and melting the obtained molten metal into a mold or a cooling plate. The mold and the cooling plate may each be equipped with a water cooling mechanism. For example, when cast into a flat plate shape, amorphization can be promoted by adjusting the composition and the cast thickness. Casting thickness is 0.1-10m
About m is preferable, but it may exceed the range depending on the composition and the cooling structure of the mold.

(Liquid quenching method) The liquid quenching method is a method in which a melt of an alloy prepared to have a predetermined composition is injected from a small nozzle onto a cooling body (for example, a roll) rotating at a high speed to quench the melt. is there. The cooling rate is mainly controlled by the plate thickness of the sample obtained by quenching, and the plate thickness of the sample is roll material, roll peripheral speed, nozzle hole diameter, gap between roll and nozzle,
It can be adjusted by the molten metal injection pressure.

The optimum material for the roll is determined by its wettability with the molten alloy, and a Cu-based alloy (for example, Cu, TiC) is used.
u, ZrCu, BeCu), Fe-based alloy (eg, SK
D, SUJ) or a ceramic roll having good thermal conductivity (for example, Al ₃ N ₄ , which may be a coating on the roll surface).

Since a large amount of heat needs to be taken from the molten alloy for mass production, it is preferable to increase the heat capacity of the roll. Therefore, the roll diameter is 30
The diameter is preferably 0 mmφ or more, and more preferably 500 mmφ or more. The width of the roll is 50
The thickness is preferably at least mm, and more preferably 100 mm or more.

The nozzle hole diameter is preferably in the range of 0.3 to 10 mm. When the nozzle hole diameter is less than 0.3 mm, it becomes difficult to inject the molten metal from the nozzle. On the other hand, when the nozzle hole diameter exceeds 10 mm, a thick sample is likely to be obtained, and it is difficult to obtain an amorphous phase.

The gap between the roll and the nozzle is
It is preferable to set it within the range of 0.2 to 20 mm, but even if the gap exceeds 20 mm, there is no problem as long as the cooling rate is uniformly increased by making the flow of the molten metal laminar. However, widening the gap gives a thicker sample,
The wider the gap, the slower the cooling rate.

Although the roll peripheral speed depends on the material composition, it can be made amorphous easily by setting the roll peripheral speed within the range of 1 to 60 m / s. When the roll peripheral speed is less than 1 m / s, a mixed phase of a fine crystal phase and an amorphous phase is easily obtained. On the other hand, the roll peripheral speed is 6
If it exceeds 0 m / s, it becomes difficult for the molten alloy to ride on the cooling roll that rotates at a high speed, so that the cooling rate decreases and the fine crystalline phase tends to precipitate.

According to the gas atomizing method and the rotating disk method, an almost spherical alloy can be obtained. Cooling conditions, that is, in the case of the gas atomizing method, by controlling the ratio of the gas amount to the molten metal supply amount, and in the case of the rotating disk method, by controlling manufacturing parameters such as the material of the cooling disk and the number of revolutions, the amorphous phase is substantially controlled. An alloy consisting of can be obtained. A powdery sample can be obtained by a gas atomizing method, a rotating disk method, a rotating electrode method, or the like. In these methods, a spherical sample can be obtained by selecting the conditions, and therefore the negative electrode material can be packed in the negative electrode most closely, which may be preferable for increasing the capacity of the battery.

Since the first and second negative electrode materials according to the present invention have extremely high activity, it is preferable to carry out from the production of the negative electrode material to the production of the negative electrode in a non-oxidizing atmosphere as much as possible.

When compared by the manufacturing method, the use of the alloy produced by the single roll method or the casting method makes it possible to maintain the discharge capacity and the capacity as compared with the case of using the alloy produced by the gas atomization or the rotating disk method. The rate can be improved, and the maximum capacity reaching charge / discharge frequency can be reduced.

<Third Non-Aqueous Electrolyte Battery Negative Material> The third non-aqueous electrolyte battery negative electrode material according to the present invention has a composition represented by the general formula (3) and has an average crystal grain size. 5
It contains an alloy containing a fine crystalline phase of 00 nm or less.

A _a M _b T _c X _d Z _e (3) wherein A is one or more elements selected from the group consisting of Ca, Sr and Ba, or the elements and other alkaline earth metals. And M is at least one element selected from the group consisting of Ni and Cu, and T is Si, Al, In, Ge, P, Pb, Bi, S.
one or more elements selected from the group consisting of b, Zn, Ga and C, and X is Fe, Co, Mn, Cr, T
i, V, Zr, Nb, Hf, Ta, Mo, W and one or more elements selected from the group consisting of rare earth elements, Z is one or more elements selected from the group consisting of O, C, H and N And a, b, c, d and e are a + b + c
+ D + e = 100 atom%, 20 ≦ a ≦ 85, 15 ≦ b ≦
80, 0 ≦ c ≦ 40, 0 ≦ d ≦ 20, and 0 ≦ e ≦ 20 are satisfied.

The third negative electrode material may be substantially composed of a fine crystal phase, or may be substantially composed of a composite phase of the fine crystal phase and another phase (for example, an amorphous phase). Is also good.

The fine crystalline phase may be made of an intermetallic compound, a compound having a non-stoichiometric composition, or an alloy having a non-stoichiometric composition.

When the average grain size of the fine crystalline phase exceeds 500 nm, the pulverization of the negative electrode material proceeds faster, so that when it is used as an electrode, the electrical contact between the negative electrode materials or between the conductive additive and the negative electrode material decreases. , The discharge capacity becomes low and the charge / discharge cycle life becomes short. A more preferable range of the average particle size is 5n
m or more and 500 nm or less, more preferably 5 n
m or more and 300 nm or less. The structure may be composed of one kind or a plurality of kinds of fine crystal phases, or may be one kind or a plurality of kinds of fine crystal phases surrounded by at least a part of crystal phases having different compositions. It has a crystal structure with a grain size of 5 to 500 nm or less.

For the average crystal grain size of the fine crystal phase, at least 50 crystal grains adjacent to each other in a transmission electron microscope (TEM) photograph (for example, 100,000 times) are selected, and the maximum length of each crystal grain is measured. Then, the average value is calculated. The magnification of the TEM photograph can be changed according to the size of the crystal grain size to be measured.

The ratio of the fine crystal phase in the composite phase of the fine crystal phase and the amorphous phase is (a) thermal analysis or (b) X.
It is measured by line diffraction.

(A) Thermal Analysis Thermal analysis of an alloy consisting of an amorphous phase produces heat at the crystallization temperature, so the amount of heat generated is taken as the reference amount of heat generation. The ratio of the fine crystalline phase is evaluated by performing thermal analysis on the alloy in which the proportion of the fine crystalline phase is unknown and comparing the calorific value with the reference calorific value.

(B) X-ray Diffraction Based on the diffraction intensity of the strongest peak in the X-ray diffraction pattern of an alloy of which the proportion of the fine crystalline phase is known, the intensity of the same diffraction peak of the alloy whose proportion of the fine crystalline phase is unknown is The proportion of the fine crystalline phase is evaluated by comparing the reference strengths.

(Alkaline Earth Metal Element A) The alkaline earth metal element A contains at least one of Ca, Sr and Ba as an essential component. The element A has a function of facilitating occlusion / release of lithium. The reason for limiting the atomic ratio a of the element A within the range of 20 to 85 atomic% is for the reason described below.
If the atomic ratio a of the element A is less than 20 atomic%, the lithium occlusion / desorption rate decreases, and it becomes difficult to improve the discharge rate characteristics of the non-aqueous electrolyte battery. On the other hand, when the atomic ratio a of the element A exceeds 85 atomic%, the retained amount of the absorbed lithium in the alloy increases, so that the discharge capacity of the non-aqueous electrolyte battery remarkably decreases. A more preferable range of the atomic ratio a is 25 to 80 atomic%.

Among the alkaline earth metal elements A, those having two kinds of Ca and Sr as essential components are preferable.
And Ba are essential components, Sr and Ba are essential components, and Ca, Sr, and Ba are essential components. The ratio of the essential components consisting of one or more elements selected from the group consisting of Ca, Sr and Ba is such that the atomic ratio of the alkaline earth metal element A is 100.
When the atomic percentage is set, it is desirable that the atomic percentage be 50 atomic% or more. This is because if the ratio is less than 50 atom%, the discharge capacity may not be sufficiently improved. It is preferably at least 60 atom%.

Mg is preferable as the other alkaline earth metal element A used in combination with Ca, Sr, and Ba.

(Element M) By combining the element M with the alkaline earth metal element A, fine crystallization can be promoted. Further, the element M can suppress pulverization when lithium is occluded and released in the negative electrode material. The atomic ratio b of the element M is limited to the range of 15 to 80 atomic% for the following reason. If the atomic ratio b is outside the above range, fine crystallization becomes difficult. A more preferable range of the atomic ratio b of the element M is 20 to 75 atomic%.

Particularly, it is desirable to use Cu as the element M. With such a structure, fine crystallization of the alloy can be promoted.

(Element T) Element T is an element capable of alloying with lithium. Therefore, by containing the element T in the negative electrode material, the amount of lithium stored can be increased, and the capacity of the non-aqueous electrolyte battery can be improved. However, if the atomic ratio c of the element T exceeds 40 atomic%, fine crystallization becomes almost difficult. Therefore, the element T
The atomic ratio c of is preferably 40 atomic% or less,
A more preferable range is 35 atomic% or less. If the amount of the atomic ratio c is less than 2 atomic%, the effect of improving the battery capacity may not be obtained. Therefore, the lower limit of the atomic ratio c is preferably 2 atomic%.

Among the elements T, Si, In and Al are preferable.

(Element X) As the rare earth element, for example,
La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, T
Examples thereof include b, Dy, Ho, Er, Tm, Yb and Lu. Among them, La, Ce, Pr, Nd and Sm are preferable.

Fine crystallization can be promoted by containing the element X in an atomic ratio of 20 atomic% or less. It is also effective in reducing the retention of the occluded Li in the alloy and suppressing the capacity decrease during charge and discharge.

(Element Z) The element Z is at least one element selected from the group consisting of O, C, H and N. These elements are elements that work effectively for fine crystallization, but depending on the manufacturing process and amount, they may form oxides, carbides, hydrides, and nitrides to form multiple phases. No problem. In particular, oxides, carbides, hydrides and nitrides can be finely dispersed and precipitated at crystal grain boundaries to promote fine crystallization. If the amount e exceeds 20 atom%, the capacity decreases, so the amount e is made 20 atom% or less. It is preferably 15 atomic% or less.

Since the third negative electrode material for a non-aqueous electrolyte battery according to the present invention described above is relatively easy for lithium ions or lithium atoms to move in and out, the discharge when the discharge rate of the non-aqueous electrolyte battery is increased. The decrease in capacity can be suppressed, that is, the discharge rate characteristic can be improved. Moreover, the number of times of charging and discharging to reach the maximum capacity can be reduced. Further, since the volume expansion / contraction ratio due to lithium ions or lithium atoms coming in and out can be reduced, the capacity deterioration due to pulverization can be reduced, and the charge / discharge cycle life of the secondary battery can be improved.

According to the present invention, the following (III) and (V) are mentioned as one of the causes for facilitating the entry and exit of lithium ions or lithium atoms.

(III) Sr and Ba combine with Li to form B
Since aLi ₄ and SrLi ₄ can be formed, a high capacity can be achieved. On the other hand, Ca is effective for improving the cycle life.

(V) Ca, Sr, and Ba have a larger atomic radius than Mg and Be, which are the same alkaline earth elements, so that the composition represented by the above-mentioned formula (3) is used, Li having a large atomic radius can be easily taken in and out.

Furthermore, in the third negative electrode material for a non-aqueous electrolyte battery according to the present invention, since the alloying element does not contain lithium, the element is easy to handle when synthesizing the negative electrode material and the liquid quenching method is used. There is no risk of ignition when synthesizing the negative electrode material, and mass production is easy. Therefore, it is advantageous for the cycle life of the electrode characteristics. Further, the manufacturing yield of the negative electrode material can be increased because it is unlikely to be affected by fluctuations in heat treatment conditions.

<Fourth Non-Aqueous Electrolyte Battery Anode Material> The fourth non-aqueous electrolyte battery negative electrode material according to the present invention has a composition represented by the following general formula (4) and has an average crystal grain size. Contains a fine crystalline phase of 500 nm or less, a negative electrode material for a non-aqueous electrolyte battery.

[A _a M _b T _c X _d Z _e ] _x Li _y (4) wherein A is at least one element selected from the group consisting of Ca, Sr and Ba, or other than the above elements. M is at least one element selected from the group consisting of Ni and Cu, and T is Si, Al, In, Ge, P, Pb, Bi, S.
one or more elements selected from the group consisting of b, Zn, Ga and C, and X is Fe, Co, Mn, Cr, T
i, V, Zr, Nb, Hf, Ta, Mo, W and at least one element selected from the group consisting of rare earth elements, and Z is at least 1 selected from the group consisting of O, C, H and N
With at least one element, the atomic ratios a, b, c, d, e, x and y are a + b + c + d + e = 1, x + y = 100 atomic%, 0.2 ≦ a ≦ 0.85, 0.15 ≦ b ≦ 0.8, 0
≦ c ≦ 0.4, 0 ≦ d ≦ 0.2, 0 ≦ e ≦ 0.2, 0 <
Each of y ≦ 30 is satisfied.

The fourth negative electrode material for non-aqueous electrolyte battery is
Lithium is included in the constituents, and the atomic ratio a,
Except that the total of b, c, d, and e is set to 1, it has the same structure as the above-mentioned third negative electrode material for non-aqueous electrolyte battery.

The atomic ratio y of lithium will be described below.

(Li) Lithium is an element responsible for charge transfer in the non-aqueous electrolyte battery. For this reason, when lithium is contained as an alloy constituent element, the amount of lithium stored / released in the negative electrode can be improved, and the battery capacity and charge / discharge cycle life can be improved. Further, since the fourth negative electrode material is more easily activated than the third negative electrode material, the maximum discharge capacity can be obtained relatively early in the charge / discharge cycle.

By the way, when the constituent element does not contain lithium as in the case of the third negative electrode material, it is necessary to use a lithium-containing compound such as a lithium composite metal oxide for the positive electrode active material. According to the fourth negative electrode material, a compound containing no lithium as a constituent element can be used as the positive electrode active material, and the types of usable positive electrode active material can be expanded. However, if the lithium content z exceeds 30 atomic%, fine crystallization becomes difficult and the charge / discharge cycle life of the secondary battery is shortened.

The third to fourth negative electrode materials are produced, for example, by the methods described in (i) to (iii) below.

(I) By subjecting the above-mentioned first and second negative electrode materials to a heat treatment at a crystallization temperature or higher, a fine crystalline phase is precipitated to obtain third to fourth negative electrode materials. In particular, when a small amount of the element T is contained in the negative electrode material, the average crystal grain size becomes 50
It becomes easy to control to 0 nm or less. Among the elements T, Zr, Hf, Nb, Ta, Mo, W, and rare earth elements 4d, 4f, and 5d transition metals can be added in small amounts to obtain a high accelerating effect in grain refinement. It should be noted that with respect to Ti, V, and Cr of the element T, increasing the amount of addition can promote the refinement of crystal. Further, the element Z is combined with the alkaline earth metal element, the element T, and the like, and is homogeneously dispersed in the crystal grain boundaries, so that fine crystallization can be promoted.

(Ii) Fine crystals can be directly deposited by the liquid quenching method. In this case, by adjusting the cooling rate of the molten metal, it is possible to precipitate a crystal grain of an appropriate size at an optimum ratio. The cooling rate depends on the plate thickness of the material to be rapidly cooled, and the plate thickness is preferably controlled by the peripheral speed of the cooling roll, the roll material, the molten metal supply amount (nozzle hole diameter), and the like. In particular, when two or more elements T are selected, it is easy to obtain an alloy with fine crystal grains. The alloy obtained by the liquid quenching method may be heat-treated thereafter.

(Iii) After blending each element so as to have a predetermined composition, the molten metal obtained by melting is cast into a mold or a cooling plate to obtain third to fourth negative electrode materials. The mold and the cooling plate may each be equipped with a water cooling mechanism. For example, when cast into a flat plate shape, amorphization can be promoted by adjusting the composition and the cast thickness. Casting thickness is 0.5-10m
About m is preferable, but it may exceed the range depending on the composition and the cooling structure of the mold.

According to the gas atomizing method and the rotating disk method, an almost spherical alloy can be obtained. Cooling conditions, that is, in the case of the gas atomizing method, by controlling the ratio of the gas amount to the molten metal supply amount, and in the case of the rotating disk method, by controlling manufacturing parameters such as the material of the cooling disk and the number of revolutions, the amorphous phase is substantially controlled. An alloy consisting of can be obtained. A powdery sample can be obtained by a gas atomizing method, a rotating disk method, a rotating electrode method, or the like. In these methods, a spherical sample can be obtained by selecting the conditions, and therefore the negative electrode material can be packed in the negative electrode most closely, which may be preferable for increasing the capacity of the battery.

Since the third to fourth negative electrode materials according to the present invention have extremely high activity, it is preferable to carry out from the production of the negative electrode material to the production of the negative electrode in a non-oxidizing atmosphere as much as possible.

When compared by the manufacturing method, the use of the alloy produced by the single roll method or the casting method makes it possible to maintain the discharge capacity ratio and the capacity compared to the case of using the alloy produced by the gas atomization or the rotating disk method. The rate can be improved, and the maximum capacity reaching charge / discharge frequency can be reduced.

Of the first to fourth negative electrode materials according to the present invention, the first and second negative electrode materials have higher discharge rate characteristics and charge / discharge cycle life than the third and fourth negative electrode materials. In addition, the number of times of charge / discharge required to reach the maximum capacity can be reduced as compared with the third and fourth negative electrode materials.

Next, the non-aqueous electrolyte battery according to the present invention will be described.

The non-aqueous electrolyte battery according to the present invention comprises a negative electrode containing at least one of the first to fourth negative electrode materials, a positive electrode, and a non-aqueous electrolyte layer arranged between the positive electrode and the negative electrode. .

1) Negative Electrode The negative electrode includes a current collector and a negative electrode layer formed on one or both sides of the current collector and containing at least one of the first to fourth negative electrode materials.

This negative electrode is produced, for example, by kneading the powder of the negative electrode material and the binder in the presence of an organic solvent, applying the obtained suspension to a current collector, drying and pressing. It

The first and second negative electrode materials may be embrittled by being heat-treated at a temperature equal to or lower than the crystallization temperature for 0.1 to 24 hours before crushing. As the pulverizing method, for example, a pin mill, a jet mill, a hammer mill, a ball mill or the like can be adopted.

On the other hand, regarding the third to fourth negative electrode materials,
As in the method described in (i) above, a sample once amorphized is heated to the crystallization temperature of 0.1-2.
When synthesizing by heat treatment for 4 hours, it is desirable that the crushing treatment be performed after the heat treatment. In addition, (ii) to (iii) described above
In the case of the sample in which the fine crystal phase is directly precipitated as in the method of No. 1, it does not matter whether or not the heat treatment is performed before the pulverization.

Examples of the binder include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVdF), ethylene-propylene-diene copolymer (EPDM), styrene-butadiene rubber (SBR),
Carboxymethyl cellulose (CMC) or the like can be used.

The mixing ratio of the negative electrode material and the binder is preferably in the range of 90 to 98% by weight of the negative electrode material and 1 to 10% by weight of the binder.

As the current collector, any conductive material can be used without particular limitation. Above all,
A foil, mesh, punched metal, lath metal, or the like made of copper, stainless steel, or nickel can be used.

2) Positive Electrode The positive electrode includes a current collector and a positive electrode active material-containing layer formed on one surface or both surfaces of the current collector and containing a positive electrode active material.

For this positive electrode, for example, a positive electrode active material, a conductive agent and a binder are appropriately suspended in a solvent, and the obtained suspension is applied on the surface of a current collector, dried and pressed. It is made.

The positive electrode active material is not particularly limited as long as it can occlude an alkali metal such as lithium during discharge of the battery and release the alkali metal during charge. Examples of the positive electrode active material include various oxides and sulfides, and examples thereof include manganese dioxide (MnO ₂ ), lithium manganese composite oxide (eg, LiMn ₂ O ₄ , L
iMnO ₂ ), lithium nickel composite oxide (for example,
LiNiO ₂ ), lithium cobalt composite oxide (eg LiCoO ₂ ), lithium nickel cobalt composite oxide (eg LiNi _1-X Co _X O ₂ ), lithium manganese cobalt composite oxide (eg LiMn _X Co _1-X). O
₂ ), vanadium oxide (for example, V ₂ O ₅ ) and the like. In addition, organic materials such as conductive polymer materials and disulfide-based polymer materials are also included. More preferable positive electrode active materials are lithium manganese composite oxides (for example, LiMn ₂ O ₄ ), lithium nickel composite oxides (for example, LiNiO ₂ ), lithium cobalt composite oxides (for example, LiCoO ₂ ), and lithium which have high battery voltage. Nickel-cobalt composite oxide (for example, LiNi _0.8 Co
_0.2 O ₂ ), lithium manganese cobalt composite oxide (for example, LiMn _X Co _1-X O ₂ ) and the like.

Examples of the binder include polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (P
VdF), fluorocarbon rubber, and the like.

Examples of the conductive agent include acetylene black, carbon black, graphite and the like.

The compounding ratio of the positive electrode active material, the conductive agent and the binder is 80 to 95 wt% of the positive electrode active material and 3 to 20 wt% of the conductive agent.
%, And the binder is preferably in the range of 2 to 7 wt%.

As the current collector, any electrically conductive material can be used without particular limitation. Particularly, as the current collector for the positive electrode, it is preferable to use a material which is not easily oxidized during the battery reaction, for example, aluminum. , Stainless steel, titanium, etc. can be used.

3) Non-Aqueous Electrolyte Layer The non-aqueous electrolyte layer can impart ionic conductivity between the positive electrode and the negative electrode.

As the non-aqueous electrolyte layer, for example, a separator holding a non-aqueous electrolytic solution, a gel non-aqueous electrolyte layer, a separator holding a gel non-aqueous electrolyte, a solid polymer electrolyte layer, an inorganic solid electrolyte A layer etc. can be mentioned.

As the separator, for example, a porous material can be used. As such a separator,
For example, synthetic resin non-woven fabric, polyethylene porous film, polypropylene porous film and the like can be mentioned.

The non-aqueous electrolytic solution is prepared, for example, by dissolving the electrolyte in a non-aqueous solvent.

As the non-aqueous solvent, for example, a cyclic carbonate such as ethylene carbonate (EC) or propylene carbonate (PC), or a mixed solvent of these cyclic carbonates and a non-aqueous solvent having a viscosity lower than that of the cyclic carbonate is mainly used. A non-aqueous solvent can be used. Examples of the low-viscosity non-aqueous solvent include chain carbonates (for example, dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate, etc.), γ-butyrolactone, acetonitrile, methyl propionate, ethyl propionate, cyclic ethers (for example, tetrahydrofuran. , 2-methyltetrahydrofuran, etc.) and chain ethers (eg, dimethoxyethane, diethoxyethane, etc.).

A lithium salt is used as the electrolyte. Specifically, lithium hexafluorophosphate (LiP
F ₆ ), lithium borofluoride (LiBF ₄ ), lithium arsenic hexafluoride (LiAsF ₆ ), lithium perchlorate (Li
ClO ₄ ), lithium trifluorometasulfonate (L
iCF ₃ SO ₃ ) and the like. Especially, lithium hexafluorophosphate (LiPF ₆ ) and lithium borofluoride (L
iBF ₄₎ are preferred examples.

The amount of the electrolyte dissolved in the non-aqueous solvent was 0.
It is preferably 5 to 2 mol / L.

The gelled non-aqueous electrolyte can be obtained, for example, by combining a non-aqueous electrolyte and a polymer material. Examples of the polymer material include polymers of monomers such as polyacrylonitrile, polyacrylate, polyvinylidene fluoride (PVdF), and polyethylene oxide (PECO), or copolymers with other monomers.

The solid polymer electrolyte layer is obtained, for example, by dissolving an electrolyte in a polymer material and solidifying it.
Examples of such polymer materials include polymers of monomers such as polyacrylonitrile, polyvinylidene fluoride (PVdF), and polyethylene oxide (PEO), or copolymers with other monomers.

Examples of the inorganic solid electrolyte include a ceramic material containing lithium.
_{Li 3 N, Li 3 PO 4} -Li 2 S-SiS 2, LiI-L
such as i ₂ S-SiS ₂ glass and the like.

A thin non-aqueous electrolyte secondary battery, which is an example of the non-aqueous electrolyte battery according to the present invention, will be described in detail with reference to FIGS. 1 and 2.

FIG. 1 is a sectional view showing a thin non-aqueous electrolyte secondary battery which is an example of the non-aqueous electrolyte battery according to the present invention.
FIG. 2 is an enlarged cross-sectional view showing part A of FIG. 1.

As shown in FIG. 1, an electrode group 2 is housed in an exterior material 1 made of, for example, a laminated film. The electrode group 2 has a structure in which a laminate including a positive electrode, a separator and a negative electrode is wound into a flat shape. As shown in FIG. 2, the laminate includes a separator 3, a positive electrode layer 4, a positive electrode current collector 5, and a positive electrode 6 having a positive electrode layer 4, a separator 3, a negative electrode layer 7, and a negative electrode collector (from the bottom of the drawing). A negative electrode 9 provided with an electric body 8 and a negative electrode layer 7, a separator 3, a positive electrode layer 4, a positive electrode current collector 5, a positive electrode 6 provided with the positive electrode layer 4, a separator 3, a negative electrode layer 7, and a negative electrode current collector 8 were provided. The negative electrode 9 is formed by stacking in this order. The negative electrode current collector 8 is located in the outermost layer of the electrode group 2. The nonaqueous electrolyte is held in the electrode group 2. One end of the strip-shaped positive electrode lead 10 is connected to the positive electrode current collector 5 of the electrode group 2, and the other end thereof extends from the exterior material 1. On the other hand, a strip-shaped negative electrode lead 1
1 has one end connected to the negative electrode current collector 8 of the electrode group 2 and the other end extending from the exterior material 1.

In the above-mentioned FIGS. 1 and 2, an example of using the electrode group in which the positive electrode, the non-aqueous electrolyte layer, and the negative electrode are flatly wound has been described, but the positive electrode, the non-aqueous electrolyte layer, and the negative electrode are The present invention can be applied to an electrode group composed of the above laminated body, and an electrode group having a structure in which the laminated body of the positive electrode, the non-aqueous electrolyte layer, and the negative electrode is folded once or more.

[0128]

EXAMPLES (Examples 1 to 15) <Production of Negative Electrode> After heating and melting each element in the ratio shown in Table 1, the peripheral speed was 20 by a single roll method in an inert atmosphere.
Cooling roll that rotates at a speed of m / s (roll material is Be
(Cu alloy), a molten alloy was injected from a nozzle hole of 1 mmφ and rapidly cooled to obtain a flake-shaped (for example, ribbon-shaped or plate-shaped) sample.

When the crystallinity of the obtained alloys of Examples 1 to 15 was examined by an X-ray diffraction method, it was confirmed that no peak due to the crystal phase was observed. FIG. 3 shows the X-ray diffraction pattern (X-ray; CuKα) for the alloy of Example 1.

For the average interplanar spacing of the broadest strongest peaks in X-ray diffraction, the strongest diffraction peak position (2θ) was obtained from this X-ray diffraction result, and the Bragg equation 2d sin θ = λ (C
In the case of ukα ray, the average surface spacing d is obtained from λ = 1.5418Å). X-ray diffraction evaluation condition is voltage 50
It is kV and current is 100 mA.

After cutting the obtained alloy, it was pulverized by a jet mill to obtain an alloy powder having an average particle size of 10 μm.

94% by weight of this alloy powder, 3% by weight of graphite powder as a conductive material, 2% by weight of styrene-butadiene rubber as a binder, and 1% by weight of carboxymethylcellulose as an organic solvent were mixed in water. A suspension was prepared by dispersing. This suspension is a current collector, and the film thickness is 1
A copper foil having a thickness of 8 μm was applied, dried, and then pressed to produce a negative electrode.

<Production of Positive Electrode> 91 wt% of lithium cobalt oxide powder, 6 wt% of graphite powder and 3 wt% of polyvinylidene fluoride were mixed, and this was mixed with N-methyl-2-.
A slurry was prepared by dispersing in pyrrolidone. This slurry was applied to an aluminum foil as a current collector, dried, and then pressed to produce a positive electrode.

<Preparation of Lithium Ion Secondary Battery> A separator made of polyethylene porous film was prepared.
An electrode group was produced by spirally winding with a separator interposed between the positive electrode and the negative electrode. Further, lithium hexafluorophosphate as an electrolyte was dissolved in a mixed solvent of ethylene carbonate and methyl ethyl carbonate (volume ratio 1: 2) at 1 mol / liter to prepare a non-aqueous electrolytic solution.

After the electrolysis group was housed in a bottomed cylindrical container made of stainless steel, a nonaqueous electrolyte solution was injected and a sealing treatment was performed to assemble a cylindrical lithium ion secondary battery.

(Examples 16 to 30) After heating and melting the respective elements in the ratios shown in Table 2, the elements were cast into a mold having a water cooling structure in an inert atmosphere to obtain a plate-like sample having a thickness of 1 mm. It was

When the crystallinity of the obtained alloys of Examples 16 to 30 was examined by an X-ray diffraction method, it was confirmed that no peak due to the crystal phase was observed. Also, the average interplanar spacing was calculated from the obtained X-ray diffraction pattern, and the results are also shown in Table 2 below.

A cylindrical lithium ion secondary battery was assembled in the same manner as described in Example 1 except that the above alloy was used.

(Examples 31 to 34) Powder samples having the compositions shown in Table 3 below were obtained by the gas atomizing method.

When the crystallinity of the obtained alloys of Examples 31 to 34 was examined by an X-ray diffraction method, it was confirmed that no peak due to the crystal phase was observed. Further, the average interplanar spacing was calculated from the obtained X-ray diffraction pattern, and the results are also shown in Table 3 below.

A cylindrical lithium ion secondary battery was assembled in the same manner as described in Example 1 above, except that the obtained powder sample was used as it was as the negative electrode material without being crushed.

(Examples 35 to 38) Powder samples having the compositions shown in Table 3 below were obtained by the rotating disk method.

When the crystallinity of the obtained alloys of Examples 35 to 38 was examined by an X-ray diffraction method, it was confirmed that no peak due to the crystal phase was observed. Further, the average interplanar spacing was calculated from the obtained X-ray diffraction pattern, and the results are also shown in Table 3 below.

A cylindrical lithium ion secondary battery was assembled in the same manner as described in Example 1 above, except that the obtained powder sample was used as it was as the negative electrode material without being crushed.

(Examples 39 to 53) Cooling rolls (roll material) rotated at a peripheral speed of 20 m / s by a single roll method in an inert atmosphere after heating and melting the respective elements in the ratios shown in Table 4 On a BeCu alloy), a molten alloy was injected from a 0.8 mmφ nozzle hole and rapidly cooled to obtain a flake-shaped (for example, ribbon-shaped or plate-shaped) sample.

When the crystallinity of the obtained alloys of Examples 39 to 53 was examined by an X-ray diffraction method, a peak based on the crystal phase was confirmed. FIG. 4 shows the X-ray diffraction pattern (X-ray; CuKα) for the alloy of Example 39. As is clear from FIG. 4, the alloy of Example 39 shows a peak based on the crystal phase in the X-ray diffraction pattern.

1) Measurement of proportion of fine crystalline phase in alloy X-ray diffraction of the sample to be determined with reference to the diffraction intensity of the strongest peak in the X-ray diffraction pattern of the sample which was sufficiently crystallized (100% of fine crystalline phase). The ratio of the strongest peak in the pattern to the diffraction intensity was calculated, and the ratio of the fine crystalline phase in the sample was evaluated from the obtained ratio. The results are also shown in Table 4 below.

2) Measurement of average crystal grain size of fine crystal phase A transmission electron microscope (TEM) photograph (for example, 100,000 times) was taken, and the crystal grains of 50 crystal grains adjacent to each other in this TEM photograph were taken. Measure the maximum diameter of each
The average is shown in Table 4 below as the average crystal grain size. In addition,
The magnification of the TEM photograph can be changed according to the size of the crystal grain to be measured.

Other than using such alloy powder,
A lithium ion secondary battery was assembled in the same manner as described in Example 1 above.

(Examples 54 to 68) After heating and melting the respective elements in the ratios shown in Table 5, they were cast into a mold having a water cooling structure in an inert atmosphere to obtain plate-shaped samples having a thickness of 2 mm. It was

When the crystallinity of the obtained alloys of Examples 54 to 68 was examined by an X-ray diffraction method, a peak based on the crystal phase was confirmed.

Further, with respect to the alloys of Examples 54 to 68, the average crystal grain size and the ratio of the fine crystal phase were measured in the same manner as described in Example 39, and the results are also shown in Table 5 below. .

A cylindrical lithium ion secondary battery was assembled in the same manner as described in Example 1 except that the above alloy was used.

(Examples 69 to 72) Powder samples having the compositions shown in Table 6 below were obtained by the gas atomizing method.

When the crystallinity of the obtained alloys of Examples 69 to 72 was examined by an X-ray diffraction method, a peak based on the crystal phase was confirmed.

Further, with respect to the alloys of Examples 69 to 72, the average crystal grain size and the ratio of the fine crystal phase were measured in the same manner as described in Example 39, and the results are shown in Table 6 below. .

A cylindrical lithium ion secondary battery was assembled in the same manner as described in Example 1 above, except that the obtained powder sample was used as a negative electrode material as it was without crushing.

(Examples 73 to 76) Powder samples having the compositions shown in Table 6 below were obtained by the rotating disk method.

When the crystallinity of the obtained alloys of Examples 73 to 76 was examined by an X-ray diffraction method, a peak based on the crystal phase was confirmed.

Further, with respect to the alloys of Examples 73 to 76, the average crystal grain size and the ratio of the fine crystal phase were measured in the same manner as described in Example 39, and the results are also shown in Table 6 below. .

A cylindrical lithium ion secondary battery was assembled in the same manner as described in Example 1 above, except that the obtained powder sample was used as a negative electrode material as it was without crushing.

(Comparative Example 1) 325 instead of alloy powder
Mesophase pitch carbon fiber heat-treated at 0 ° C. (average fiber diameter 10 μm, average fiber length 25 μm, surface spacing d ₀₀₂ is 0.3355 nm, specific surface area by BET method is 3 m ² /
A lithium ion secondary battery was assembled in the same manner as in Example 1 except that the carbonaceous powder of g) was used.

Comparative Example 2 A lithium ion secondary battery was assembled in the same manner as in Example 1 except that Al powder having an average particle size of 10 μm was used instead of the alloy powder.

(Comparative Example 3) 1 by the mechanical alloying method
The Sn ₃₀ Co ₇₀ alloy was produced over a period of 00 hours. It was confirmed by X-ray diffraction that the obtained alloy was amorphized. A lithium ion secondary battery was assembled in the same manner as in Example 1 described above except that such an alloy was used.

Comparative Examples 4 to 6 Si was used as the negative electrode material.₃₃
Ni₆₇Alloy, (Al_0.1Si_0.9)₃₃Ni₆₇Alloy, Cu ₅₀
Ni_{twenty five}Sn_{twenty five}The alloy was made by the single roll method. In addition, low
The material is BeCu alloy, and the roll peripheral speed is 25 m / s.
It was. The obtained alloy was finely crystallized by X-ray diffraction.
I was sure that. In addition, as described in the above-mentioned Example 39.
The average crystal grain was obtained by TEM observation in the same manner as
The results are shown in Table 7 below. Using such an alloy
Except for the above, the lithium-ion battery
The next battery was assembled.

Comparative Example 7 A Fe ₇₅ Si ₂₅ alloy was obtained as an anode material by the atomization method. The obtained sample had an average crystal grain size of 300 nm. A lithium ion secondary battery was assembled in the same manner as in Example 1 described above except that such an alloy was used.

Comparative Example 8 An alloy prepared to have a composition of Ca ₅₀ Sn ₅₀ was prepared by a chemical method. In particular,
Ca of CaCO ₃ solution and SnCl ₂ aqueous solution: Sn ratio of 1: prepared at 1, after the combined pH of the aqueous solution to 6.5, defines a NaBH ₄ aqueous solution to precipitate the CaSn alloy. When X-ray diffraction (CuKα) was performed, only broad diffraction lines were confirmed, and it was confirmed that an amorphous phase was obtained.

(Comparative Example 9) A mother alloy having a composition of Mg ₈₂ Ni ₁₈ was prepared and supercooled by a single roll method in an inert atmosphere,
A long thin ribbon sample having a plate thickness of 15 μm was obtained. The nozzle hole diameter is 0.6 mm, the roll material is BeCu alloy, the roll peripheral speed is 30 m / s, and the roll-nozzle gap is 0.7 mm. When the rapidly cooled sample was subjected to X-ray diffraction (CuKα), a broad diffraction line peak was found at 2θ = 38.3 °, and it was confirmed that an amorphous phase was obtained.

Obtained Examples 1-76 and Comparative Examples 1-9
Regarding the secondary battery of, the discharge capacity by the method described below,
The capacity retention rate, the rate characteristics, and the number of times of charge / discharge reaching the maximum capacity were measured, and the results are also shown in Tables 1 to 7 below.

<Discharge Capacity and Capacity Retention Ratio> Each secondary battery was charged at 20 ° C. with a charging current of 1.5 A to 4.2 V over 2 hours and then discharged to 2.7 V at 1.5 A. A discharge cycle test was performed and the discharge capacity ratio and the capacity retention ratio at the 300th cycle were measured. The results are shown in Tables 1 to 7 below.
Shown in. The discharge capacity ratio was expressed as a ratio when the discharge capacity of Comparative Example 1 was set to 1, and the capacity retention ratio was expressed as a discharge capacity at the 300th cycle when the maximum discharge capacity was 100%.

<Rate Characteristics> For each secondary battery, 20
After charging at 4.2C constant current / constant voltage at 1C rate for 1 hour under the environment of ℃, measure the discharge capacity when discharging to 3.0V at 0.1C rate. The discharge capacity was obtained. After charging under the same conditions, the discharge capacity when discharged to 3.0 V at a 1C rate was measured to obtain the discharge capacity at 1C. The discharge capacity at 1 C is represented by setting the discharge capacity at 0.1 C as 100%, and the results are shown as rate characteristics in Tables 1 to 7 below.

<Maximum Capacity Reaching Charge / Discharge Count> For each secondary battery, the number of cycles required to reach the maximum discharge capacity when the charge / discharge cycle of 1 C was repeated was measured, and the results are shown in Table 1 below. 7 shows.

[0173]

[Table 1]

[0174]

[Table 2]

[0175]

[Table 3]

[0176]

[Table 4]

[0177]

[Table 5]

[0178]

[Table 6]

[0179]

[Table 7]

As is clear from Tables 1 to 7, Example 1
It can be seen that the secondary batteries Nos. To 76 simultaneously satisfy the discharge capacity, the capacity retention ratio at the 300th cycle, the rate characteristics, and the number of times of charge / discharge until reaching the maximum capacity.

In particular, the secondary batteries of Examples 1 to 38 provided with the alloy substantially consisting of an amorphous phase maintain the capacity as compared with the secondary batteries of Examples 39 to 76 provided with the alloy containing the fine crystalline phase. The rate tended to be excellent. Further, when comparing the amorphous phase and the fine crystalline phase by the same manufacturing method, for example, in the single roll method, the secondary batteries of Examples 1 to 15 are compared with the secondary batteries of Examples 39 to 53. Thus, the maximum capacity reaching charge / discharge frequency tends to decrease.

Further, when compared by the manufacturing method, for example, in the amorphous phase, the secondary batteries of Examples 1 to 30 using the alloys manufactured by the single roll method or the casting method are
Compared with the secondary batteries of Examples 31 to 38 using the alloy produced by the gas atomizing or rotating disk method, the discharge rate characteristics are excellent, and the maximum capacity reaching charge / discharge frequency tends to decrease. On the other hand, in Examples 39 to 76, the secondary batteries of Examples 39 to 68 using the alloy produced by the single roll method or the casting method are the examples using the alloy produced by the gas atomizing or the rotating disk method. Compared to the secondary batteries of Nos. 69 to 76, the maximum capacity reaching charge / discharge frequency was not reduced.

On the other hand, in the secondary battery of Comparative Example 1 using the carbonaceous material as the negative electrode material, the discharge capacity, the capacity retention ratio at the 300th cycle, and the rate characteristics were all Examples 1 to 76.
You can see that it is inferior to. Further, the secondary battery of Comparative Example 2 using Al metal as the negative electrode material has a higher discharge capacity than Examples 1 to 76, but is inferior in the capacity retention rate and rate characteristics at the 300th cycle. on the other hand,
The secondary batteries of Comparative Examples 3 to 4 had a higher maximum capacity reaching charge / discharge frequency than those of Examples 1 to 76. Furthermore, Comparative Example 5
It can be seen that the secondary batteries Nos. 9 to 9 are inferior in capacity retention rate and rate characteristics at the 300th cycle to Examples 1 to 76.

Observation of the negative electrode after repeating charge and discharge for 300 cycles revealed that no change was observed in the alloys in the negative electrodes used in Examples 1 to 76. Dendride was deposited. As a result of the deposition of Al dendrides, it is speculated that the secondary battery of Comparative Example 2 had a high initial battery discharge capacity, but the capacity retention rate after 300 cycles was significantly reduced. Further, Al dendride easily reacts with the electrolytic solution, so that the safety of the battery is deteriorated.

In the above-mentioned embodiment, the example applied to the cylindrical non-aqueous electrolyte secondary battery has been described, but the same applies to the rectangular non-aqueous electrolyte secondary battery and the thin non-aqueous electrolyte secondary battery. be able to.

Further, in the above-mentioned embodiment, the example applied to the non-aqueous electrolyte secondary battery has been described, but when applied to the non-aqueous electrolyte primary battery, the discharge capacity and the discharge rate characteristic can be improved.

[0187]

As described above, according to the present invention, it has excellent discharge capacity, cycle life and discharge rate characteristics,
Further, it is possible to provide a negative electrode material for a non-aqueous electrolyte battery, a negative electrode and a non-aqueous electrolyte battery, which reach the maximum capacity with the minimum number of charge / discharge cycles.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a thin non-aqueous electrolyte secondary battery which is an example of a non-aqueous electrolyte battery according to the present invention.

FIG. 2 is an enlarged cross-sectional view showing a portion A of FIG.

3 is a characteristic diagram showing an X-ray diffraction pattern for the negative electrode material of Example 1. FIG.

FIG. 4 is a characteristic diagram showing an X-ray diffraction pattern for the negative electrode material of Example 39.

[Explanation of symbols]

1 ... Exterior material, 2 ... Electrode group, 3 ... separator, 4 ... Positive electrode layer, 5 ... Positive electrode current collector, 6 ... Positive electrode, 7 ... Negative electrode layer, 8 ... Negative electrode current collector, 9 ... Negative electrode, 10 ... Positive electrode terminal, 11 ... Negative electrode terminal.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01M 10/40 H01M 10/40 Z (72) Inventor Shinsuke Matsuno 1 Komukai Toshiba-cho, Kawasaki-shi, Kanagawa Prefecture 1 Address Company Toshiba Research & Development Center (72) Inventor Norio Takami 1 Komukai Toshiba-cho, Sachi-ku, Kawasaki City, Kanagawa F-Term Company Toshiba Research & Development Center 5H024 AA03 AA09 AA11 CC04 CC12 FF31 HH01 HH13 5H029 AJ02 AJ03 AJ05 AK02 AK03 AL11 AM02 AM03 AM04 AM05 AM07 BJ04 BJ14 DJ17 DJ18 EJ04 EJ12 HJ02 HJ05 5H050 AA02 AA07 AA08 BA06 BA17 CA02 CA08 CA09 CA11 CB11 EA09 EA24 FA19 FA20 HA02 HA05

Claims (6)

[Claims] 1. A negative electrode material for a non-aqueous electrolyte battery, which has a composition represented by the following general formula (1) and contains an alloy consisting essentially of an amorphous phase. A _a M _b T _c X _d Z _e (1) where A is at least one element selected from the group consisting of Ca, Sr and Ba, or from the above elements and other alkaline earth metal elements. And M is one or more elements selected from the group consisting of Ni and Cu, and T is Si, Al, In, Ge, P, Pb, Bi, S.
one or more elements selected from the group consisting of b, Zn, Ga and C, and X is Fe, Co, Mn, Cr, T
i, V, Zr, Nb, Hf, Ta, Mo, W and one or more elements selected from the group consisting of rare earth elements, Z is one or more elements selected from the group consisting of O, C, H and N And a, b, c, d and e are a + b + c +
d + e = 100 atom%, 30 ≦ a ≦ 80, 20 ≦ b ≦ 7
0, 0 ≦ c ≦ 40, 0 ≦ d ≦ 20, and 0 ≦ e ≦ 20 are satisfied. 2. A negative electrode material for a non-aqueous electrolyte battery, which has a composition represented by the following general formula (2) and contains an alloy consisting essentially of an amorphous phase. [A _a M _b T _c X _d Z _e ] _x Li _y (2) where A is one or more elements selected from the group consisting of Ca, Sr and Ba, or the elements and other alkaline earths. And M are one or more elements selected from the group consisting of Ni and Cu, and T is Si, Al, In, Ge, P, Pb, Bi, S.
one or more elements selected from the group consisting of b, Zn, Ga and C, and X is Fe, Co, Mn, Cr, T
i, V, Zr, Nb, Hf, Ta, Mo, W and one or more elements selected from the group consisting of rare earth elements, Z is one or more elements selected from the group consisting of O, C, H and N And the atomic ratios a, b, c, d, e, x and y
Is a + b + c + d + e = 1, x + y = 100 atom%,
0.3 ≦ a ≦ 0.8, 0.2 ≦ b ≦ 0.7, 0 ≦ c ≦
0.4, 0 ≦ d ≦ 0.2, 0 ≦ e ≦ 0.2, 0 <y ≦ 3
0 is satisfied respectively. 3. A negative electrode material for a non-aqueous electrolyte battery, comprising an alloy having a composition represented by the following general formula (3) and containing a fine crystalline phase having an average crystal grain size of 500 nm or less. A _a M _b T _c X _d Z _e (3) where A is one or more elements selected from the group consisting of Ca, Sr and Ba, or is a combination of the above elements and other alkaline earth metal elements. And M is one or more elements selected from the group consisting of Ni and Cu, and T is Si, Al, In, Ge, P, Pb, Bi, S
one or more elements selected from the group consisting of b, Zn, Ga and C, and X is Fe, Co, Mn, Cr, T
i, V, Zr, Nb, Hf, Ta, Mo, W and one or more elements selected from the group consisting of rare earth elements, Z is one or more elements selected from the group consisting of O, C, H and N And a, b, c, d and e are a + b + c +
d + e = 100 atom%, 20 ≦ a ≦ 85, 15 ≦ b ≦ 8
0, 0 ≦ c ≦ 40, 0 ≦ d ≦ 20, and 0 ≦ e ≦ 20 are satisfied. 4. A negative electrode material for a non-aqueous electrolyte battery, comprising an alloy having a composition represented by the following general formula (4) and containing a fine crystalline phase having an average crystal grain size of 500 nm or less. [A _a M _b T _c X _d Z _e ] _x Li _y (4) where A is one or more elements selected from the group consisting of Ca, Sr and Ba, or the elements and other alkaline earths. And M are one or more elements selected from the group consisting of Ni and Cu, and T is Si, Al, In, Ge, P, Pb, Bi, S.
one or more elements selected from the group consisting of b, Zn, Ga and C, and X is Fe, Co, Mn, Cr, T
i, V, Zr, Nb, Hf, Ta, Mo, W and one or more elements selected from the group consisting of rare earth elements, Z is one or more elements selected from the group consisting of O, C, H and N And the atomic ratios a, b, c, d, e, x and y
Is a + b + c + d + e = 1, x + y = 100 atom%,
0.2 ≦ a ≦ 0.85, 0.15 ≦ b ≦ 0.8, 0 ≦ c
≦ 0.4, 0 ≦ d ≦ 0.2, 0 ≦ e ≦ 0.2, 0 <y ≦
Satisfy each 30. 5. A negative electrode comprising the negative electrode material for a non-aqueous electrolyte battery according to any one of claims 1 to 4. 6. A non-aqueous electrolyte battery comprising a negative electrode containing the negative electrode material for a non-aqueous electrolyte battery according to claim 1, a positive electrode, and a non-aqueous electrolyte.