JPH07235295A - Nonaqueous secondary battery - Google Patents

Abstract

PURPOSE:To provide a nonaqueous secondary battery with high discharge working voltage, high energy density, high charge/discharge performance, and high safety. CONSTITUTION:A nonaqueous secondary battery consists of a positive active material, a negative active material prepared by previously inserting 0.5-4.5 equivalent lithium before accommodating in a battery container into an oxide and/or sulfide of mainly at least one semimetal of the IV-B and V-B groups in the periodic table or an oxide and/or a sulfide containing at least on of In, Zn, and Mg, and a nonaqueous electrolyte containing a lithium salt.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention improves charge / discharge characteristics,
The present invention also relates to a non-aqueous secondary battery with improved safety.

[0002]

2. Description of the Related Art Lithium metal and lithium alloys are typical as negative electrode active materials for non-aqueous secondary batteries. When they are used, lithium metal grows in a dendritic form during charge / discharge, causing internal short circuit. , The activity of the dendritic metal itself is high,
There is a risk of ignition. On the other hand, recently, a calcined carbonaceous material capable of inserting and releasing lithium has come into practical use. The disadvantage of this carbonaceous material is that it has conductivity, so that lithium metal may be deposited on the carbonaceous material during overcharging or rapid charging, resulting in the deposition of dendritic metal. It will be. In order to avoid this, we have devised a charger or adopted a method of reducing the amount of positive electrode active material to prevent overcharge, but the latter method limits the amount of active material. Therefore, the discharge capacity is also limited. Also,
Since the carbonaceous material has a relatively low density, the discharge capacity is limited by the double meaning that the capacity per volume is low. On the other hand, as the negative electrode active material other than lithium metal, lithium alloy, or carbonaceous material, TiS ₂ , LiTiS capable of inserting and extracting lithium.
₂ (US Pat. No. 3,983,476), transition metal oxides having a rutile structure, such as WO ₂ (US Pat.
8,476), spinel compounds such as Li _x Fe (Fe ₂ ) O ₄ (JP-A-58-220362), and electrochemically synthesized lithium compounds of Fe ₂ O ₃ (US Pat. No. 4,464). , 447), a lithium compound of Fe ₂ O ₃ (Japanese Patent Laid-Open No. 3-112,070), Nb ₂ O ₅ (Japanese Patent Publication No.
2-59,412, JP 2-824,47), iron _{oxide, FeO, Fe 2 O 3,} Fe 3 O 4, cobalt oxide,
CoO, Co ₂ O ₃ , Co ₃ O ₄ (JP-A-3-291,
862) is known. Since all of these compounds have a high redox potential, a non-aqueous secondary battery having a high discharge potential of 3 V class and a high capacity has not been realized.

As an example of using SnO ₂ or a Sn compound as an active material for a lithium battery, Li as a positive electrode active material for a secondary battery is used.
_1.03 Co _0.95 Sn _0.04 O ₂ (EP86-106, 30
1), the addition of SnO ₂ to V ₂ O ₅ of the secondary battery positive electrode active material (JP-A-2-158,056), the addition of SnO ₂ to α-Fe ₂ O ₃ of the secondary battery negative electrode active material (SnO ₂ Of 0.5 to 10 mol%) (JP-A-62-219,
465), SnO _{2 as a} positive electrode active material for primary batteries (electrochemistry and industrial physical chemistry, vol. 46, No. 7, page 407, 197).
8 years) is known. In addition, as an example of using SnO ₂ or a Sn compound for an electrochromic electrode, SnO ₂ is used.
₂ can reversibly insert Li ions (Journal of Electrochemical Society, Vol. 140, No. 5, L81, 1993), 8 mol% S in InO _2.
It is known that an n-doped film (ITO) can reversibly insert Li ions (Solid State Ionics 28-30, page 1733, published in 1988). However, in the electrochromic system, since the electrode is made transparent to be used as a thin film by a vapor deposition method or the like, it is generally operated at a considerably low current unlike the practical range of the battery. In "Solid State Ionics" of the above document, 1
Experimental examples of μA to 30 μA / cm ² are shown.

As an example of using a Ge oxide as an active material of a lithium battery, a positive electrode active material of a secondary battery, V ₂ O ₅ containing G
It is known to add eO ₂ (JP-A-2-158,056) and use GeO or GeO ₂ (JP-A-55-96,567) as a positive electrode active material for primary batteries. As an example of using Pb oxide as an active material of a lithium battery, use of PbO _x as a positive electrode active material of a primary battery (x = 1.4 to 1.
8) (British Patent 78-6,271), as a cathode active material for primary _{cells, PbO, PbO 2, Pb 2} O 3, Pb 3
Use of O ₄ (Materials Chemistry and Physics Vol. 25, No. 2, p. 207, 1990
Year) is known. As an example of using Sb oxide as an active material of a lithium battery, use of Sb oxide as a positive electrode active material of a primary battery (German Patent 2,516,70
3) is known. As an example of using a Bi oxide as an active material of a lithium battery, use of Bi ₂ O ₃ as a positive electrode active material of a primary battery (Japanese Patent Laid-Open No. 52-12425).
A composite oxide of Bi and Pb (Japanese Patent Laid-Open No. 59-151,761) is known as a positive electrode active material for primary batteries. As a metal that forms an alloy with lithium, Pb, Sn, and Sb are lithium alloy negative electrode active materials (Belgium Patent 873,06).
Known as 8).

As a positive electrode active material, LiMn₂O_Four, L
i₂MnO₃, Γ-βMnO₂And LiMn₂O_FourComposite of
Oxide, γ-βMnO₂And Li₂MnO₃Complex oxidation of
Thing, LiCoO₂, LiCo_0.5Ni_0.5O₂, LiN
iO₂, V₂O_Five, Amorphous V₂O_Five, V₆O₁₃, LiV
₃O₈, VO₂(B), Ti compound TiS₂, Mo
Compound MoS₂, MoO₃, LiMo₂O_FourIs known
Has been. Positive electrode active material, both of which are metal chalcogenides
As a combination of quality and negative electrode active material, TiS₂And LiTi
S₂(US Pat. No. 983,476), chemically synthesized
Li_0.1V₂O_FiveAnd LiMn_1-sMe_sO₂(0.1
<S <1 Me = transition metal JP-A-63-210,02
8), the same Li_0.1V₂O_FiveAnd LiCo_1-sFe_sO
₂(S = 0.05-0.3 63-21 1,56
4), the same Li_0.1V₂O_FiveAnd LiCo_1-sNi_sO
₂(S = 0.5 to 0.9 JP-A-1-294,36
4), V₂O_FiveAnd Nb₂O_Five+ Lithium metal (JP-A-2
-82447), V₂O_FiveAnd TiS₂Electrochemically
Li made_xFe₂O₃(U.S. Pat. No. 4,464,4
47 Journal of Power Sources Volume 8 2
89, 1982), Li as a positive electrode active material and a negative electrode active material
Ni_xCo_1-xO₂(0 ≦ x <1 JP-A-1-120,
765 In the specification, from the examples, the positive electrode active material and the negative electrode active material are described.
The substances are described as the same compound. ), LiCoO₂
Or LiMn₂O_FourAnd iron oxide, FeO, Fe
₂O₃, Fe₃O_Four, Cobalt oxide, CoO, Co₂O
₃Or Co₃O_Four(JP-A-3-291,862)
Which is known. However, any of these pairs
Non-aqueous secondary battery with low capacity and poor cycle characteristics.
It is a pond.

A method is also known in which a transition metal oxide containing Co, V or the like is used as a negative electrode active material precursor, and lithium is inserted therein before it is stored in a battery container to be used as a negative electrode active material (EP 0,567). , 149 A1) has the drawbacks of low battery voltage and low energy density.

[0007]

An object of the present invention is to obtain a non-aqueous secondary battery having high discharge voltage, high energy density and good charge / discharge cycle characteristics.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to insert and release lithium as a negative electrode active material from periodic table IVB, V.
An oxide and / or sulfide mainly composed of a group B semimetal, or at least one oxide and / or sulfide selected from In, Zn and Mg, and used as a negative electrode active material precursor. Before storing lithium and a certain oxide and / or sulfide in a battery container, 0.5 to 4.5
This could be achieved by inserting an equivalent amount of lithium.

In the present invention, the IVB and / or VB group semimetals in the Periodic Table are Ge, Sn, Pb, Sb and Bi.

The precursor of the negative electrode active material referred to in the present invention will be described. For example, α-PbO structure SnO or rutile structure SnO ₂ itself does not work as a negative electrode active material of a secondary battery, but if lithium is continuously inserted into them, the crystal structure changes, and as a negative electrode active material of a secondary battery. It has been discovered that it can work reversibly. That is, the charge / discharge efficiency in the first cycle is about 4 although it depends on the type of the negative electrode active material precursor.
It is as low as 0 to 80%. Therefore, in the present invention, the starting materials such as α-PbO structure SnO and rutile structure S are used.
A compound such as nO ₂ , that is, a compound before lithium is inserted will be referred to as a “negative electrode active material precursor”. In the present invention, by inserting a predetermined amount of lithium into the negative electrode active material precursor and storing it in a battery container for use,
The charge and discharge efficiency of the first cycle can be remarkably improved, the battery capacity can be greatly improved, and the cycleability can be improved.

Negative electrode active material or precursor thereof referred to in the present invention
As specific examples of the body, GeO, GeO ₂, SnO, Sn
S, SnO₂, SnS₂, GeS, GeS₂, InS,
PbO, PbS, PbO₂, Pb₂O₃, Pb₃O_Four,
Sb₂O₃, Sb₂O_Four, Sb ₂O_Five, Bi₂O₃, B
i₂O_Four, Bi₂O_Five, InO, ZnO, Li₂SnO
₃, SiSnO₃, InS, ZnS, MgS or it
And non-stoichiometric compounds of these oxides. Those
Among them, SnO and SnO₂, GeO, GeO ₂, S
nS, Li₂SnO₃, SiSnO₃Is preferred, especially
SnO, SnO₂, SnS, Li₂SnO₃, SiSn
O₃Is preferred. α-PbO structure SnO, rutile structure S
nO₂, GeO, Rutile structure GeO₂Is preferred, especially
α-PbO structure SnO, rutile structure SnO₂Is preferred
Yes.

The negative electrode active material precursor of the present invention may contain various compounds. For example, transition metals (elements of the 4th, 5th and 6th periods of the periodic table belonging to groups IIIA to IB), elements of the group IIIB of the periodic table, alkali metals (periodic table). IA, IIA elements), P, C
l, Br, I, F can be included. For example, S
In nO ₂ , various compounds that increase electron conductivity (for example,
Sb, In, Nb compound) dopant, or Si may be contained as a homologous element. The amount of compound added is 0
-20 mol% is preferable.

As a method of synthesizing the precursor of the negative electrode active material, Sn is used.
In O ₂ , an Sn compound, for example, an aqueous solution of stannic chloride, stannic bromide, stannic sulfate, stannic nitrate and an alkali hydroxide, for example, lithium hydroxide, sodium hydroxide, potassium hydroxide, Calcium hydroxide, magnesium hydroxide,
An aqueous solution such as ammonium hydroxide is mixed to precipitate stannic hydroxide, which is washed and separated. After the stannic hydroxide is almost dried, it is fired at 250 to 2000 ° C. in air, a gas rich in oxygen or a gas lean in oxygen. Alternatively, the stannic hydroxide can be baked as it is and then washed. The average size of the primary particles is preferably 0.01 μm to 1 μm as measured by a scanning electron microscope. Particularly, 0.02 μm to 0.2 μm is preferable.
The average size of the secondary particles is preferably 0.1 to 60 μm. Similarly, with SnO, an aqueous solution of stannous chloride, stannous bromide, stannous sulfate, and stannous nitrate and an alkali hydroxide such as lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide are used. , An aqueous solution of magnesium hydroxide, ammonium hydroxide and the like are mixed and boiled. Also,
Stannous oxalate in a gas with a low oxygen content, 250-1000
Bake at ℃. The average particle size is 0.1-60 μ
m is preferred. . Other oxides are SnO ₂ and SnO.
Similarly, can be synthesized by a well-known method.
Its preferable physical properties are the same as those of SnO described above. A well-known crusher or classifier is used to obtain a predetermined particle size. For example, a mortar, a ball mill, a vibrating ball mill, a satellite ball mill, a planetary ball mill, a swirling airflow type jet mill, a sieve and the like are used.

A chemical method or an electrochemical method can be used as a method of inserting lithium in advance before housing the negative electrode active material precursor in the battery container. The method of chemically inserting lithium directly reacts with the negative electrode active material precursor and lithium metal, lithium alloy (lithium-aluminum alloy, etc.), lithium compound (n-butyllithium, lithium hydride, lithium aluminum hydride, etc.). It is a method to let. In this case, the negative electrode active material precursor and the lithium insertion agent may be reacted directly with each other,
The reaction may be carried out in the presence of an anhydrous solvent (dimethoxyethane, tetrahydrofuran, ethylene carbonate, diethyl carbonate, etc.) or in the presence of an electrolytic solution (such as a solution of a supporting salt such as LiPF ₆ dissolved in the anhydrous solvent). As a preferred embodiment in this case, for example,
The negative electrode active material precursor powder and the lithium metal powder are kneaded directly or in the presence of the electrolytic solution to insert lithium into the negative electrode active material precursor, or after the negative electrode active material precursor is molded into a sheet, the electrolyte solution A method of pressure-bonding with a lithium metal sheet in the presence thereof can be mentioned. Further, a method of immersing the negative electrode active material precursor powder or sheet in an n-butyllithium solution to insert lithium is also preferable. In the chemical method,
By carrying out the lithium insertion reaction at a temperature of about 25 to 80 ° C., lithium can be inserted more efficiently, more preferably 30 to 75 ° C., particularly preferably 30 to 70 ° C.

As a method for electrochemically inserting lithium ions, a target oxide (a negative electrode active material precursor referred to in the present invention) as a positive electrode active material and lithium metal or a lithium alloy (lithium- The most preferable method is to discharge an oxidation-reduction system consisting of a non-aqueous electrolyte containing a lithium salt and an aluminum alloy in an open system. In this case, it is preferable to apply a current of 0.02 to 0.2 A per 1 g of the oxide as the precursor, and more preferably 0.03.
To 0.15 A, particularly preferably 0.04 to 0.1
2A. As another embodiment of the method of electrochemically inserting lithium ions, a method of charging a redox system comprising a lithium-containing transition metal oxide as a positive electrode active material, a negative electrode active material precursor, and a non-aqueous electrolyte containing a lithium salt You can also mention

The amount of lithium inserted varies depending on the type of the negative electrode active material precursor used, but the lithium insertion equivalent is preferably 0.5 to 4.5 equivalents relative to the negative electrode active material precursor. More preferably, it is 1 to 4 equivalents, and most preferably 1.5 to 3.5 equivalents. The term "before insertion into the battery container" means immediately before to about 30 days before storage, preferably immediately before to 10 days before, and most preferably immediately before to 5 days before. In this case, housing means that the battery constituent elements are housed in a battery container and further caulked to form a battery.

The negative electrode active material of the present invention can be obtained by inserting lithium into its precursor. The method is to insert lithium in advance as described above before storing it in the battery container. Although it is preferable that the lithium insertion is insufficient by only this method, the negative electrode active material precursor in which a predetermined amount of lithium is inserted in advance is used as the positive electrode active material,
It can be obtained by charging the battery after storing it in a battery container together with the non-aqueous electrolyte. In this case, the amount of lithium inserted is preferably 8 equivalents with respect to the negative electrode active material precursor, more preferably 7 equivalents, and most preferably 6 equivalents.

The positive electrode active material used in the present invention may be a transition metal oxide capable of reversibly inserting and releasing lithium ions, but a lithium-containing transition metal oxide is particularly preferable.

Free of lithium used in the present invention
V as a transition metal oxide positive electrode active material₂O_Five, V₆0₁₃
 , MnO₂, TiS₂, MoS₂, MoS₃, MoV
₂O ₈, NbSe₃And so on. Also,
As a preferable lithium-containing transition metal oxide positive electrode active material
Is lithium-containing Ti, V, Cr, Mn, Fe, Co,
Examples thereof include oxides containing Ni, Cu, Mo and W. Also
Alkali metals other than lithium (periodic table IA, II
A element), semi-metal Al, Ga, In, Ge, Sn,
You may mix Pb, Sb, Bi, etc. Mixing amount is 0
10 mol% is preferable.

The more preferable lithium-containing transition metal oxide positive electrode active material used in the present invention is the sum of lithium compound / (transition metal compound), where the transition metal is T
It is preferable that the compounds are mixed so that the molar ratio of i, V, Cr, Mn, Fe, Co, Ni, Mo and W) is 0.3 to 2.2.

As a particularly preferable lithium-containing transition metal oxide positive electrode active material used in the present invention, the sum of lithium compound / (transition metal compound)
V, Cr, Mn, Fe, Co, and Ni) are preferably mixed and synthesized so that the molar ratio of them is 0.3 to 2.2. Particularly preferable lithium-containing transition metal oxide positive electrode active material used in the present invention is Lix MOz (where M = Co, Mn, Ni, V,
Transition metal containing at least one selected from Fe), x
= 0.3 to 1.2 and z = 1.4 to 3).

Further preferred Lithiu used in the present invention
The lithium-containing metal oxide positive electrode active material may be Li_xCo
O₂, Li_xNiO₂, Li_xCo_aNi_1-aO₂, L
i_zCo _bV_1-bO_z, Li_xCo_bFe_1-bO₂, L
i_xMn₂O_Four, Li_xMn_cCo_2-cO_Four, Li_xM
n_cNi_2-cO_Four, Li_xMn_cV_2-cO_z, Li_xM
n _cFe_2-cO_Four, Li_xMn₂O_FourAnd MnO₂A mixture of
Thing, Li_2xMnO₃And MnO₂Mixture of Li_xMn₂
O_Four, Li_2xMnO₃And MnO₂A mixture of (where x =
0.6-1.2, a = 0.1-0.9, b = 0.8-
0.98, c = 1.6 to 1.96, z = 2.01 to 5)
I can give you.

Further preferred Lithiu used in the present invention
The lithium-containing metal oxide positive electrode active material may be Li_xCo
O₂, Li_xNiO₂, Li_xCo_aNi_1-aO₂, L
i_xCo _bV_1-bO_z, Li_xCo_bFe_1-bO₂, L
i_xMn₂O_Four, Li_xMn_cCo_2-cO_Four, Li_xM
n_cNi_2-cO_Four, Li_xMn_cV_2-cO_Four, Li_xM
n _cFe_2-cO_Four(Where x = 0.7 to 1.04, a =
0.1 to 0.9, b = 0.8 to 0.98, c = 1.6 to
1.96, z = 2.01 to 2.3).

The most preferable lithium-containing transition metal oxide positive electrode active material used in the present invention is Li _x CoO 2.
₂ , Li _x NiO ₂ , Li _x Co _a Ni _1-a O ₂ , Li
_x Mn ₂ O ₄ , Li _x Co _b V _1-b O _z (where x =
0.7-1.1, a = 0.1-0.9, b = 0.9-
0.98, z = 2.01 to 2.3). The most preferable lithium-containing transition metal oxide positive electrode active material used in the present invention is Li _x CoO ₂ , Li _x NiO.
₂ , Li _x Co _a Ni _1-a O ₂ , Li _x Mn ₂ O ₄ , L
i _x Co _b V _1-b O _z (where x = 0.7 to 1.04,
a = 0.1 to 0.9, b = 0.9 to 0.98, z = 2.
02-2.3). Here, the above x value is
It is a value before the start of charging / discharging, and increases / decreases due to charging / discharging. At the time of synthesizing the positive electrode active material of the present invention, as a method of chemically inserting lithium ions into a transition metal oxide, a method of synthesizing by reacting lithium metal, lithium alloy or butyl lithium with the transition metal oxide is preferable. . The positive electrode active material can be synthesized by a method of mixing and firing a lithium compound and a transition metal compound or a solution reaction, but a firing method is particularly preferable. The firing temperature used in the present invention may be a temperature at which a part of the mixed compound used in the present invention is decomposed and melted, for example, 250 to 200.
0 degreeC is preferable and 350-1500 degreeC is especially preferable.
The firing gas atmosphere used in the present invention is not particularly limited, but the positive electrode active material may be in air or in a gas having a high oxygen content (for example, about 30% or more), and the negative electrode active material may be in air or an oxygen content. Less gas (eg about 10%
Below) or inert gas (nitrogen gas, argon gas)
Medium is preferred.

The average particle size of the positive electrode active material used in the present invention is not particularly limited, but is preferably 0.1 to 50 μm. A well-known crusher or classifier is used to obtain a predetermined particle size. For example, a mortar, a ball mill, a vibrating ball mill, a satellite ball mill, a planetary ball mill, a swirling airflow type jet mill, a sieve and the like are used.

The oxide (precursor) of the present invention has a crystal structure, but as lithium is inserted, the crystallinity decreases and the crystallinity changes. Therefore, the structure in which reversible redox is performed as the negative electrode active material is presumed to be a compound having high amorphousness. Therefore, the oxide (precursor) of the present invention
May have a crystalline structure, an amorphous structure, or a mixed structure thereof. Examples of the negative electrode active material that can be used in combination with the present invention include lithium metal and lithium alloy (Al,
Al-Mn (U.S. Pat. No. 4,820,599), Al
-Mg (JP-A-57-98977), Al-Sn (JP-A-63-6,742), Al-In, Al-Cd (JP-A-1-144,573), lithium ion or lithium metal -A calcined carbonaceous compound that can be released (for example, JP-A-58-209,864, 61-214,
417, the same 62-88, 269, the same 62-216,
170, same 63-13, 282, same 63-24, 5
55, the same 63-121, 247, the same 63-121,
257, 63-155, 568, 63-276,
873, 63-314, 821, JP-A-1-20.
4,361, 1-221,859, 1-27
4,360). The purpose of using the lithium metal or lithium alloy together is to insert lithium in the battery, and does not utilize the dissolution / precipitation reaction of lithium metal or the like as the battery reaction.

A conductive agent, a binder, a filler or the like can be added to the electrode mixture. The conductive agent may be any electron-conductive material that does not cause a chemical change in the constructed battery. Usually, natural graphite (scaly graphite, flake graphite, earthy graphite, etc.), artificial graphite, carbon black, acetylene black, Ketjen black, carbon fibers and metals (copper, nickel, aluminum, silver (JP-A-63) -1
48, 554), powders, metal fibers, or polyphenylene derivatives (Japanese Patent Laid-Open No. 59-20971) can be included as one kind or a mixture thereof. The combined use of graphite and acetylene black is particularly preferred. The amount added is not particularly limited, but is preferably 1 to 50% by weight, and particularly preferably 2 to 30% by weight. For carbon and graphite, 2 to 15% by weight is particularly preferable.

The binder is usually starch, polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, regenerated cellulose, diacetyl cellulose, polyvinyl chloride, polyvinylpyrrolidone,
Tetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene butadiene rubber, polybutadiene, fluororubber,
Polysaccharides such as polyethylene oxide, thermoplastic resins, polymers having rubber elasticity and the like are used alone or as a mixture thereof. When a compound containing a functional group that reacts with lithium, such as a polysaccharide, is used, it is preferable to add a compound such as an isocyanate group to deactivate the functional group. The amount of the binder added is not particularly limited, but is preferably 1 to 50% by weight, and particularly preferably 2 to 30% by weight. As the filler, any fibrous material that does not cause a chemical change in the constructed battery can be used. Generally, olefin polymers such as polypropylene and polyethylene, fibers such as glass and carbon are used. The amount of the filler added is not particularly limited, but is preferably 0 to 30% by weight.

As the electrolyte, propylene is used as an organic solvent.
Len carbonate, ethylene carbonate, butylene car
Carbonate, dimethyl carbonate, diethyl carbonate
, Methyl ethyl carbonate, γ-butyrolacto
1,2-dimethoxyethane, tetrahydrofuran,
2-methyltetrahydrofuran, dimethylsulfoxy
De, 1,3-dioxolane, formamide, dimethylpho
Lumamide, dioxolane, acetonitrile, nitrogen
Tan, methyl formate, methyl acetate, methyl propionate,
Ethyl propionate, phosphoric acid triester (JP-A-60
-23,973), trimethoxymethane (Japanese Patent Laid-Open No. 61-
4,170), dioxolane derivative (JP-A-62-1)
5,771, 62-22,372, 62-108,
474), sulfolane (JP-A-62-31959),
3-methyl-2-oxazolidinone (JP-A-62-4)
4,961), propylene carbonate derivative
62-290,069, 62-290,071), TE
Trahydrofuran derivative (JP-A-63-32,87)
2), diethyl ether (JP-A-63-62, 16)
6), 1,3-propane sultone (Japanese Patent Laid-Open No. 63-10
At least an aprotic organic solvent such as
Solvent mixed with at least one kind and lithium soluble in the solvent
Salt, eg LiClO_Four, LiBF_Four, LiPF₆,
LiCF₃SO₃, LiCF₃CO₂, LiAsF₆,
LiSbF₆, LiB_TenCl_Ten(JP-A-57-74,9
74), lower aliphatic lithium carboxylate (JP-A-60-
41,773), LiAlCl_Four, LiCl, LiB
r, LiI (JP-A-60-247,265), chlorobot
Lanthanum (JP-A-61-165,957), four-phase
Lithium Nylborate (JP-A 61-214,376)
Which is composed of one or more salts. Above all, professional
Pyrene carbonate and / or ethylene capote and / or
Or butylene carbonate and 1,2-dimethoxyethane
And / or diethyl carbonate or propion
LiCF in a mixed solution of methyl acid₃SO₃, LiClO_Four,
LiBF _Four, LiPF₆Including at least one of
Electrolytes are preferred.

Particularly, it is preferable to contain at least ethylene carbonate and LiPF ₆ . The amount of these electrolytes added to the battery is not particularly limited, but a necessary amount can be used depending on the amount of the positive electrode active material or the negative electrode active material and the size of the battery. The volume ratio of the solvent is not particularly limited,
In the case of a mixed liquid of propylene carbonate or ethylene carbonate or butylene carbonate and 1,2-dimethoxyethane and / or diethyl carbonate, 0.4 / 0.6 to 0.6 / 0.4 (ethylene carbonate and The mixing ratio when both butylene carbonates are used is 0.4 / 0.6 to 0.6 / 0.4, and the mixing ratio when 1,2-dimethoxyethane and diethyl carbonate are both used is 0.4 / 0. 6-0.6 / 0.4) is preferable. The concentration of the supporting electrolyte is not particularly limited, but is preferably 0.2 to 3 mol per liter of the electrolytic solution.

In addition to the electrolytic solution, the following solid electrolytes can be used. Solid electrolytes are classified into inorganic solid electrolytes and organic solid electrolytes. Li-nitrides, halides, oxyacid salts, and the like are well known as inorganic solid electrolytes. Among them, Li ₃ N, LiI, Li ₅ N
_{I 2, Li 3 N-LiI} -LiOH, LiSiO 4, L
iSiO ₄ -LiI-LiOH (JP-A-49-81,8)
_{99), xLi 3 PO 4 -} (1-x) Li 4 SiO
₄ (JP-A-59-60,866), Li ₂ SiS ₃ (JP-A-60-501,731), phosphorus sulfide compound (JP-A-62-82,665) and the like are effective. In the organic solid electrolyte, a polyethylene oxide derivative or a polymer containing the derivative (JP-A-63-135,447), a polypropylene oxide derivative or a polymer containing the derivative, a polymer containing an ion-dissociating group (JP-A-62-135). 254,30
2, ibid. 62-254, 303, ibid. 63-193, 95
4), a mixture of a polymer containing an ionic dissociative group and the above aprotic electrolytic solution (U.S. Pat. Nos. 4,792,504, 4,830,939, JP-A-62-22,375 and JP-A-6-222,375.
2-22, 376, 63-2, 375, 63-2
2,776, JP-A-1-95,117) and phosphoric acid ester polymers (JP-A-61-256,573) are effective. Furthermore, there is also a method of adding polyacrylonitrile to the electrolytic solution (JP-A-62-278,774). Further, a method of using an inorganic and organic solid electrolyte in combination (Japanese Patent Laid-Open No. 60-1,
768) is also known.

As the separator, an insulating thin film having a large ion permeability and a predetermined mechanical strength is used. A sheet or non-woven fabric made of olefin polymer such as polypropylene or glass fiber or polyethylene is used because of its resistance to organic solvent and hydrophobicity. The pore size of the separator is in the range generally used for batteries. For example, 0.01 to 10 μ
m is used. The thickness of the separator is generally within the range for batteries. For example, 5 to 300 μm is used.

It is also known to add the following compounds to the electrolyte for the purpose of improving discharge and charge / discharge characteristics. For example, pyridine (JP-A-49-108,52)
5), triethylphosphite (JP-A-47-4,3)
76), triethanolamine (JP-A-52-72,4).
25), cyclic ether (JP-A-57-152,68)
4), ethylenediamine (JP-A-58-87,77)
7), n-glyme (JP-A-58-87,778), hexaphosphoric acid triamide (JP-A-58-87,779),
Nitrobenzene derivative (JP-A-58-214, 28)
1), sulfur (JP-A-59-8,280), quinoneimine dye (JP-A-59-68,184), N-substituted oxazolidinone and N, N'-substituted imidazolidinone (JP-A-5-280).
9-154,778), ethylene glycol dialkyl ether (JP-A-59-205,167), quaternary ammonium salt (JP-A-60-30,065), polyethylene glycol (JP-A-60-41). , 773), pyrrole (JP-A-60-79,677), 2-methoxyethanol-
Le (JP 60-89,075), AlCl ₃ (JP-61-88,466), conductive polymer - monomer of the electrode active material - (JP 61-161,673), triethylene phosphoramide Amide (JP-A-61-208,758), trialkylphosphine (JP-A-62-80,976), morpholine (JP-A-62-80,977), aryl compound having a carbonyl group 62-86, 67
3), hexamethylphosphoric triamide and 4-alkylmorpholine (JP 62-217,575), bicyclic tertiary amine (JP 62-217,578), oil (JP 62 -287,580), a quaternary phosphonium salt (JP-A-63-121268), a tertiary sulfonium salt (JP-A-63-121269), and the like.

Further, in order to make the electrolytic solution nonflammable, a halogen-containing solvent such as carbon tetrachloride or ethylene trifluoride chloride can be contained in the electrolytic solution. (JP-A-48-36,
632) Further, carbon dioxide gas can be included in the electrolytic solution in order to have suitability for high temperature storage. (JP-A-59-
134,567)

The mixture of the positive electrode and the negative electrode may contain an electrolytic solution or an electrolyte. For example, the ion conductive polymer or nitromethane (Japanese Patent Laid-Open No. 48-36,6).
33), a method of adding an electrolytic solution (JP-A-57-124,870) is known.

Further, the surface of the positive electrode active material can be modified. For example, the surface of the metal oxide may be treated with an esterifying agent (JP-A-55-163,779),
Treatment with a photocatalyst (JP-A-55-163,780), conductive polymers (JP-A-58-163,188, 59-14).
274), polyethylene oxide, etc. (JP-A-60-
97, 561). Also, the surface of the negative electrode active material can be modified. For example, an ion conductive polymer or polyacetylene layer is provided (JP-A-58-111276), or LiCl
(JP-A-58-142,771) and the like.

The collector of the electrode active material may be any electron conductor that does not cause a chemical change in the constructed battery. For example, for the positive electrode, in addition to stainless steel, nickel, aluminum, titanium, calcined carbon, etc. as the material, carbon on the surface of aluminum or stainless steel,
Those treated with nickel, titanium or silver, and the negative electrode are made of stainless steel, nickel, copper, titanium,
In addition to aluminum and calcined carbon, copper, stainless steel whose surface is treated with carbon, nickel, titanium or silver), an Al-Cd alloy, or the like is used. It is also used to oxidize the surface of these materials. The shape is
In addition to the foil, a film, a sheet, a net, a punched product, a lath body, a porous body, a foamed body, a molded body of a fiber group and the like are used. The thickness is not particularly limited, but is 1 to 5
Those having a diameter of 00 μm are used.

The shape of the battery can be any of coins, buttons, sheets, cylinders, corners and the like. When the shape of the battery is a coin or a button, the mixture of the positive electrode active material and the negative electrode active material is used by being compressed into a pellet shape. The thickness and diameter of the pellet are determined by the size of the battery. Further, when the battery has a sheet, cylinder, or square shape, the mixture of the positive electrode active material and the negative electrode active material is mainly used after being coated, dried, and compressed on the current collector. The coat thickness, length and width are determined by the size of the battery,
The thickness of the coat is 1-2 in the compressed state after drying.
000 μm is particularly preferable.

The application of the non-aqueous secondary battery of the present invention is not particularly limited. For example, when it is installed in an electronic device, a color notebook computer, a black and white notebook computer, a pen input computer, a pocket (palmtop) computer, a notebook. Type word processor, pocket word processor, e-book player, mobile phone, cordless phone handset, pager, handy terminal, mobile fax, mobile copy, mobile printer, headphone stereo, video movie, LCD TV, handy cleaner, portable CD, mini disk, Electric shaver, electronic translator, car phone,
There are transceivers, power tools, electronic organizers, calculators, memory cards, tape recorders, radios, backup power supplies, memory cards, etc. Other consumer products such as automobiles, electric vehicles, motors, lighting equipment, toys,
Game equipment, road conditioners, irons, watches, strobes, cameras, medical equipment (pacemakers, hearing aids, shoulder massagers, etc.), etc. Furthermore, it can be used for various military purposes and for space. It can also be combined with a solar cell.

[0040]

EXAMPLES The present invention will be described in more detail with reference to specific examples below, but the present invention is not limited to the examples as long as the gist of the invention is not exceeded. Examples Abbreviations shown in Table 1 are (1) negative electrode active material precursor of the present invention,
(2) Positive electrode active material, (3) Lithium insertion amount before storage in battery container (equivalent per 1 mol of negative electrode active material precursor), (4) Current value applied during lithium insertion (negative electrode active material precursor 1)
(ampere per gram), (5) type of electrolyte, (6) first
Time energy density (mW per 1ml cylindrical battery volume
h), (7) average discharge voltage (V) at the first time, and (8) cycle property (the number of cycles when the capacity becomes 80% of the first time discharge capacity). The method for synthesizing the electrode active material used in the examples is shown below. (A) SnO, (e) SnS, (a) LiCoO ₂ ,
(A) LiNiO ₂ , (C) LiMn ₂ O ₄ , (D) V
_{As 2} O _5, a commercially available product was used. (B) Synthesis method of SnO ₂ : S from SnCl ₄ and NaOH
n (OH) ₄ was synthesized, SnO ₂ was synthesized by firing in air at 400 ° C. for 4 hours, and crushed in a mortar. Average size of primary particles was about 0.05 μm (rutile structure) (c) Li ₂ SnO Synthesis method of ₃ : Li ₂ CO ₃ , SnO
₂ is mixed and baked in air at 1000 ° C./12 hours and then pulverized. Jet grind (d) SiSnO ₃ synthesis method: SnO and SiO ₂ are mixed and baked at 1000 ° C./12 hours in an argon atmosphere. (F) LiCoVO ₄ synthesis method: Li ₂ CO ₃ , Co
O and V ₂ O ₅ are mixed, fired in air at 700 ° C. for 10 hours, and then synthesized. (E) LiCo _0.95 V _0.05 O _2.07 synthesis method: Li ₂ CO
₃ , CoCO ₃ and NH ₄ VO ₃ are mixed and 900 ° C / 6
Synthesized by calcination for a period of time and crushed in a mortar. The types of electrolytic solutions used in the examples are shown below. (A) 1 mol / liter-LiPF ₆ -ethylene carbonate, diethyl carbonate 2/8 volume mixed solution (B) 0.9 mol / liter-LiPF ₆ , 0.1 mol / liter-LiBF ₄ -ethylene carbonate, diethyl carbonate 2/8 volume (C) 1 mol / liter-LiPF ₆ -ethylene carbonate, butylene carbonate, diethyl carbonate 2/2/6 volume mixture (d) 0.95 mol / liter-LiPF ₆ , 0.05 mol / liter-LiBF 2/6/2 volume mixture of ₄ -ethylene carbonate, diethyl carbonate and methyl propionate

Example 1 84 parts by weight of a negative electrode active material precursor, 3 parts by weight of acetylene black as a conductive agent and 8 parts by weight of graphite were mixed, and further 4 parts by weight of polyvinylidene fluoride as a binder and 1 of carboxymethyl cellulose. By weight, water was used as a medium and kneaded to obtain a slurry. The slurry was applied to both sides of a copper foil having a thickness of 18 μm by using a doctor blade coater, dried and compression-molded by a calender press machine, and a lead plate was spot-welded to the ends, and then the dew point was −40 ° C. or lower. It heat-processed at 150 degreeC / 4 hours in dry air, and produced the strip | belt-shaped negative electrode active material precursor sheet. This negative electrode active material precursor sheet was used as a positive electrode, a sheet made of lithium metal was used as a negative electrode, and a microporous polypropylene film separator (Celguard 2400) was sandwiched and pressure-bonded to obtain an electrolytic solution (1 mol / liter.LiPF ₆ -ethylene carbonate, A predetermined amount of lithium was electrochemically inserted by discharging in an open system at room temperature in the presence of an equal volume mixture of diethyl carbonate). Lithium was inserted on both sides in the same manner. This negative electrode active material precursor sheet was taken out, washed with tetrahydrofuran, dried, and then compression molded with a calendar press to obtain a negative electrode sheet (3). The amount of lithium inserted was determined from the weight change before and after the discharging operation. The above operation was performed in dry air having a dew point of -40 ° C or lower.

92 parts by weight of LiCoO ₂ as a positive electrode active material and 4 parts by weight of acetylene black as a conductive agent were mixed, and further 3 parts by weight of polytetrafluoroethylene and 1 part by weight of sodium polyacrylate were added as a binder. , A slurry obtained by kneading with water as a medium to a thickness of 2
It was applied to both sides of a 0 μm aluminum foil (support) current collector. The coated product was dried and compression-molded by a calendar press to prepare a strip-shaped positive electrode sheet (5). A lead plate was spot-welded to the end of the positive electrode sheet (5) and then heat-treated at 150 ° C. for 4 hours in dry air having a dew point of −40 ° C. or less. The prepared positive electrode sheet (5), a separator made of a microporous polypropylene film (Celguard 240
0) (4), the negative electrode sheet (3), and the separator (4) were laminated in this order, and this was spirally wound.

The wound body was housed in a bottomed cylindrical battery can (2) made of iron and plated with nickel, which also serves as a negative electrode terminal. In this case, the storage in the battery container was performed 24 hours after the completion of the electrochemical lithium ion insertion described above. Furthermore, the predetermined electrolytic solution shown in the table was injected into the battery can. Gasket (1) with battery lid (8) having positive terminal
A cylindrical battery was produced by caulking through. The positive electrode terminal (8) was connected to the positive electrode sheet (5), and the battery can (2) was connected to the negative electrode sheet (5) by a lead terminal in advance. FIG. 1 shows a cross section of the cylindrical battery. In addition, 7 is a safety valve. A charge / discharge cycle test was performed on the prepared battery at a charge end voltage of 4.2 V and a discharge end voltage of 2.8 V at a current density of ^2.5 mA / cm ² . As a negative electrode active material precursor (f)
The battery using LiCoVO ₄ was subjected to a charge / discharge cycle test at a charge end voltage of 4.2V and a discharge end voltage of 1.8V. The cycle test started from charging. The results are shown in Table 1. Table 2 shows an example of using (d) V ₂ O ₅ as the positive electrode active material. In this case, a charge / discharge cycle test was performed at a charge end voltage of 3.5V and a discharge end voltage of 1.9V. It was

Comparative Example 1 A cylindrical battery was prepared and charge / discharge evaluated in the same manner as in Example 1 except that the lithium insertion operation to the anode active material precursors a to e performed in Example 1 was not performed. Further, for the negative electrode active material precursor f, after inserting a predetermined amount of lithium,
Charge and discharge were evaluated in the same manner. The results are also shown in Tables 1 and 2.

[0045]

[Table 1]

[0046]

[Table 2]

[0047]

[Table 3]

Example 2 Both sides of the negative electrode active material precursor sheet prepared in Example 1 were sandwiched between lithium metal sheets, and an electrolyte solution (equal volume mixture of 1 mol / liter LiPF ₆ ethylene carbonate and diethyl carbonate) was present. Under, 40 ℃, 50kg /
A pressure of cm ² was applied, and lithium was inserted for a predetermined time. After that, the negative electrode active material precursor sheet was taken out, washed with tetrahydrofuran, dried, and compression-molded with a calender press to obtain a negative electrode sheet (3). The lithium insertion amount was determined from the weight change before and after the lithium insertion operation. The above operation was performed in dry air having a dew point of -40 ° C or lower. A cylindrical battery was prepared in the same manner as in Example 1, and a charge / discharge cycle test was performed. The results are shown in Table 3. (4) in Table 3
Indicates the reaction temperature upon insertion of lithium.

Comparative Example 2 A cylindrical battery was prepared in the same manner as in Example 2 except that the lithium insertion operation into the negative electrode active material precursors a to e carried out in Example 2 was not performed, and charge / discharge evaluation was performed. Further, for the negative electrode active material precursor f, after inserting a predetermined amount of lithium,
Charge and discharge were evaluated in the same manner. The results are also shown in Table 3.
As is clear from the comparison between the present invention of Examples 1 and 2 and the comparative example, the oxide or sulfide mainly composed of a semimetal of Group IVB or VB of the periodic table of the present invention was stored in the battery container before being stored. In the battery using the negative electrode in which 0.5 to 4.5 equivalents of lithium is inserted in advance, the energy density is larger than that of the battery in which less than 0.5 equivalents or more than 4.5 equivalents of lithium is inserted, and It is clear that the charge / discharge cycle characteristics are good. In addition, it is clear that the discharge voltage is higher and the energy density is higher than the battery in which lithium is inserted in advance into the oxide mainly containing elements other than IVB and VB of the periodic table before housing in the battery container. Is.

[0050]

[Table 4]

[0051]

INDUSTRIAL APPLICABILITY As in the present invention, a transition metal oxide or a lithium-containing transition metal oxide is used in the positive electrode active material, and at least one group IVB or VB group of the periodic table that inserts or releases lithium as the negative electrode active material. A metal-based oxide and / or sulfide, or an oxide and / or sulfide containing at least one of In, Zn, and Mg is used, and 0.5 to 4.5 is applied to the negative electrode before storing the battery container. By inserting an equivalent amount of lithium, it is possible to obtain a safe non-aqueous secondary battery that gives a high discharge operating voltage, a large energy density and good charge / discharge cycle characteristics.

[Brief description of drawings]

FIG. 1 shows a cross-sectional view of a cylindrical battery used in an example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Polypropylene insulating sealing body 2 Negative electrode can (battery can) that also serves as a negative electrode terminal 3 Negative electrode sheet 4 Separator 5 Positive electrode sheet 6 Nonaqueous electrolyte solution 7 Safety valve 8 Positive electrode cap also serving as a positive electrode terminal 9 PTC element 10 Sealing plate 11 Ring

Claims (4)

[Claims] 1. A positive electrode active material, an oxide mainly composed of a group IVB or VB semimetal which inserts and releases lithium, and / or
Alternatively, a sulfide, or a negative electrode active material containing at least one oxide and / or sulfide selected from In, Zn, and Mg, and a non-aqueous electrolyte containing a lithium salt are housed in a battery container. Regarding a water secondary battery, 0.5 to 4.5 equivalents of lithium are previously inserted into an oxide and / or a sulfide before insertion of lithium, which is a precursor of the negative electrode active material, before being stored in a battery container. Characteristic non-aqueous secondary battery 2. A method of previously inserting lithium into the negative electrode active material precursor is an electrochemical method, and is performed by applying a current of 0.02 to 0.2 A per 1 g of the negative electrode active material precursor. The non-aqueous secondary battery according to claim 1, wherein 3. The method of previously inserting lithium into the negative electrode active material precursor is a method by direct reaction with lithium metal, a lithium alloy or a lithium compound, and the reaction temperature is 25 to 80 ° C. The non-aqueous secondary battery according to claim 1. 4. The non-aqueous secondary battery according to claim 1, wherein the positive electrode active material is a transition metal oxide or a lithium-containing transition metal oxide.