JPH09147916A - Nonaqueous electrolyte secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve productivity of a highly safe nonaqueous secondary battery provided with a high discharge voltage and an excellent charge-discharge cycle characteristic by forming a specific protecting layer on a negative electrode and/or a positive electrode. SOLUTION: A nonaqueous secondary battery is constructed of a positive electrode and a negative electrode, which contain materials plastically storing/ releasing lithium, a nonaqueous electrolyte containing lithium salt, and a separator, and in the negative electrode and/or the positive electrode, at least one protecting layer formed of solid particles and a water soluble polymer is formed. In the protecting layer, conductive particles may be contained in addition to the solid particles and the water soluble polymer. The thickness of the protecting layer is 1-40μm desirably. An inorganic chalcogenide particle is feasible for the solid particle contained in the protecting layer. A polyacrylic derivative or a cellulose derivative is feasible for the water soluble polymer. For the conductive particle, a carbonceous compound, natural graphite, and vapor phase growth carbon are desirable in particular.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-aqueous secondary battery having improved productivity, high discharge potential, excellent life and safety.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication (Kokai) No. 61-7577 discloses a protective layer made of a substance having both electron conductivity and ionic conductivity such as lithium on the surface of a positive electrode. It is described that oxides of tungsten, molybdenum and vanadium are preferable as the substance to be contained. However, these compounds have not yet shown sufficient effects of preventing internal short circuits. Further, Japanese Patent Laid-Open No. 28173/1992 describes that a polymer film that selectively permeates the alkali metal ion is provided on the surface of the negative electrode (alkali metal or alkali metal alloy) facing the positive electrode. There is. However, the installation of these porous polymer membranes has a problem that the battery capacity is significantly reduced.

[0003]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a high discharge voltage, good charge / discharge cycle characteristics,
Further, it is to improve the productivity of the non-aqueous secondary battery having excellent safety.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a positive electrode and a negative electrode containing a material capable of reversibly inserting and extracting lithium,
In a non-aqueous secondary battery comprising a non-aqueous electrolyte containing a lithium salt and a separator, the negative electrode and / or the positive electrode has at least one protective layer, and the protective layer is composed of solid particles and a water-soluble polymer. It was achieved by a non-aqueous secondary battery characterized by.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The inventors of the present invention have demonstrated the manufacturing yield of a non-aqueous secondary battery comprising a positive electrode and a negative electrode containing a material capable of reversibly inserting and extracting lithium, a non-aqueous electrolyte containing a lithium salt, and a separator. Upon careful investigation of the cause of the problem, it was found that the protrusions and depressions on the electrode surface, scratches on the electrode surface that occur during the process from electrode transportation to battery assembly, and irregularities due to partial dropouts caused the It was found that the internal short circuit occurred largely due to the direct destruction of the separator, the delicate sliding at the time of winding, and the destruction of the separator associated with the uneven pressure. In order to prevent these internal short circuits, it is effective to provide a protective layer on the electrode surface, and it has been found that the installation of the protective layer improves the manufacturing yield and also the safety. . Further, it has been found that the protective layer does not contain a resin binder and contains a water-soluble polymer, whereby the above can be achieved without lowering the discharge capacity, particularly the discharge capacity at high current.

The preferred embodiments of the present invention are shown below, but the present invention is not limited thereto. (1) In a non-aqueous secondary battery comprising a positive electrode and a negative electrode containing a material capable of reversibly inserting and extracting lithium, a non-aqueous electrolyte containing a lithium salt, and a separator, the negative electrode and / or the positive electrode has at least a protective layer. A non-aqueous secondary battery having one layer, wherein the protective layer comprises solid particles and a water-soluble polymer. (2) In a non-aqueous secondary battery comprising a positive electrode and a negative electrode containing a material capable of reversibly occluding and releasing lithium, a non-aqueous electrolyte containing a lithium salt, and a separator, the negative electrode and / or the positive electrode has at least a protective layer. A non-aqueous secondary battery having one layer, wherein the protective layer comprises solid particles, conductive particles and a water-soluble polymer. (3) The non-aqueous secondary battery according to (1) or (2), wherein the protective layer has a thickness of 1 μm or more and 40 μm or less. (4) The non-aqueous secondary battery according to (3), wherein the protective layer is formed on the negative electrode. (5) The non-aqueous secondary battery according to (3), wherein the protective layer is formed on the positive electrode. (6) The non-aqueous secondary battery according to (3), wherein the protective layer is formed on both the positive electrode and the negative electrode. (7) The non-aqueous secondary battery according to (3), wherein the protective layer does not contain conductive particles on the positive electrode and contains conductive particles on the negative electrode. (8) Any one of (4) to (7), wherein the solid particles contained in the protective layer are inorganic chalcogenide particles.
The non-aqueous secondary battery according to the item. (9) The inorganic chalcogenide particles contain at least one oxide of sodium, potassium, magnesium, calcium, strontium, zirconium, aluminum and silicon.
The non-aqueous secondary battery according to (8), which contains a seed. (10) The non-aqueous secondary battery according to (9), wherein the oxide of (9) is alumina, silicon dioxide, or zirconia. (11) The water-soluble polymer contained in the protective layer is a polyacrylic acid derivative or a cellulose derivative.
The non-aqueous secondary battery according to any one of (8) to (10). (1
2) The non-aqueous secondary battery according to (11), wherein the conductive particles contained in the protective layer are carbon materials. (13) The non-aqueous secondary battery according to (12), wherein the negative electrode material capable of reversibly occluding and releasing lithium is a metal oxide. (14) The non-aqueous secondary battery according to (13), wherein the negative electrode is a composite oxide containing tin. (15) The non-aqueous secondary battery according to (14), wherein the tin-containing composite oxide is a composite oxide represented by the following general formula (1). SnM ¹ _a O _t General formula (1) In the formula, M ¹ is two or more selected from Al, B, P, Si, Group 1 element of the periodic table, Group 2 element, Group 3 element, and halogen element. , A is a number of 0.2 or more and 2 or less, and t is a number of 1 or more and 6 or less. (16) The non-aqueous secondary battery according to (15), wherein the tin-containing composite oxide is a composite oxide represented by the following general formula (2). SnM ² _b M ³ _c O _t General formula (2) In the formula, M ² is at least two kinds of Al, B, P and Si,
M ³ is a group 1 element, a group 2 element, a group 3 element of the periodic table,
Representing at least one kind of halogen element, b is a number of 0.2 or more and 2 or less, c is a number of 0.01 or more and 1 or less, and 0.2 <
b + c <2, t represents a number of 1 or more and 6 or less. (17) The non-aqueous secondary battery according to any one of (1) to (16), wherein the negative electrode is electrically connected to metallic lithium.

In the present invention, the protective layer is composed of at least one layer and may be composed of a plurality of layers of the same kind or different kinds. The thickness of the protective layer is preferably 1 μm or more and 40 μm or less, and more preferably 2 μm or more and 30 μm or less. Further, it is desirable that the protective layer containing these particles does not melt at 300 ° C. or lower and does not form a new film. These protective layers contain organic or inorganic solid particles having no electrical conductivity, and may also contain electrically conductive organic or inorganic solid particles. Among these particles, inorganic solid particles are more preferable.

Examples of the inorganic particles include metal, non-metal element carbides, silicides, nitrides, sulfides, and oxides. Among carbides, silicides and nitrides, Si
C, aluminum nitride (AlN), BN, and BP are preferable because they have high insulation properties and are chemically stable.
e, SiC using BN as a sintering aid is particularly preferred. Among chalcogenides, oxides are preferable, and oxides that are not easily oxidized or reduced are preferable. These oxides include Al ₂ O ₃ , As ₄ O ₆ , B ₂ O ₃ , Ba
O, BeO, CaO, Li ₂ O, K ₂ O, Na ₂ O, I
n ₂ O ₃ , MgO, Sb ₂ O ₅ , SiO ₂ , SrO, Z
rO ₂ can be mentioned. Among these, Al ₂ O ₃ , Ba
O, BeO, CaO, K ₂ O, Na ₂ O, MgO, Si
O ₂ , SrO and ZrO ₂ are particularly preferable. These oxides may be a single oxide or a composite oxide. Preferred compounds as the composite oxide include mullite (3
Al ₂ O ₃ .2SiO ₂ ), steatite (MgO.S)
iO ₂ ), forsterite (2MgO.SiO ₂ ),
Cordierite (2MgO.2Al ₂ O ₃ .5Si
O ₂ ). As the conductive particles,
Inorganic particles are preferable, metal powder, inorganic chalcogenide,
Examples include particles of carbonaceous compounds. Particularly, carbonaceous compounds, natural graphite and vapor grown carbon are preferable.

These inorganic compound particles are made into particles of 0.1 μm or more and 20 μm or less, particularly preferably 0.2 μm or more and 15 μm or less by using a method such as controlling production conditions or pulverization.

The content of the particles used in the present invention is 1-8.
0 g / m ^2, preferably from 2 to 40 g / m ^2. The protective layer is mainly formed of the solid particles having substantially no conductivity and the water-soluble polymer, or the solid particles having substantially no conductivity, the conductive solid particles and the water-soluble polymer. The ratio of the solid particles to the water-soluble polymer is preferably 40% by weight or more and 96% by weight or less, more preferably 50% by weight or more and 92% by weight or less, based on the total weight of both.
Examples of the water-soluble polymer include cellulose derivatives such as carboxymethyl cellulose and hydroxyethyl cellulose, polyacrylic acid derivatives, polyvinyl alcohol derivatives, polyethylene oxide derivatives and starch, and cellulose derivatives and polyacrylic acid derivatives are preferable.

The protective layer may be applied to either the positive electrode or the negative electrode, or may be applied to both the positive electrode and the negative electrode. Also,
When the positive electrode and the negative electrode are formed by coating the mixture on both sides of the current collector, the protective layer may be coated on both sides or may be coated on only one side. . However, it is necessary that one of the positive electrode and the negative electrode opposed via the separator is coated. The coating method of the protective layer may be a sequential method of coating a mixture containing a material capable of reversibly occluding and releasing lithium on the current collector and then sequentially coating the protective layer, or a mixture layer. A simultaneous coating method in which the protective layer and the protective layer are simultaneously coated may be used.

The positive and negative electrodes used in the non-aqueous secondary battery of the present invention can be prepared by coating a positive electrode mixture or a negative electrode mixture on a current collector. The positive electrode or negative electrode mixture can contain a conductive agent, a binder, a dispersant, a filler, an ionic conductive agent, a pressure enhancer, and various additives, respectively, in addition to the positive electrode active material or the negative electrode material.

The negative electrode material used in the present invention may be any compound capable of inserting and extracting light metal ions. These include light metals, light metal alloys, carbonaceous compounds, inorganic oxides, inorganic chalcogenides, metal complexes and organic polymer compounds, but carbonaceous compounds, inorganic oxides and inorganic chalcogenides are preferable. Furthermore, these may be used in combination. For example, a light metal and a carbonaceous compound, a light metal and an inorganic oxide, a combination of a light metal and a carbonaceous compound and an inorganic oxide, and the like can be given. These negative electrode materials are preferable because they provide high capacity, high discharge potential, high safety, and high cycle properties. Lithium is preferred as the light metal ion.

The carbonaceous compound is selected from natural graphite, artificial graphite, vapor-grown carbon, calcined carbon of an organic substance, and the like, and preferably includes a graphite structure. In addition to carbon, the carbonaceous compound may contain 0 to 10% by weight of a different compound such as B, P, N, S, SiC and B4C.

The element forming an oxide or chalcogenide is preferably a transition metal or a metal or metalloid element belonging to Groups 15 to 15 of the periodic table. As the transition metal compound,
Especially V, Ti, Fe, Mn, Co, Ni, Zn, W, M
A single or complex oxide of o or chalcogenide is preferable. Further preferred compounds include JP-A-6-44
Li _p Co _q V _1-q O _r (here, p
= 0.1-2.5, q = 0-1, z = 1.3-4.5)
Can be mentioned.

Compounds of metals other than transition metals and metalloids
Include elements of Groups 13 to 15 of the periodic table, Ga, Si,
Sn, Ge, Pb, Sb, Bi alone or their
Oxides and chalcogenides composed of two or more kinds
Is selected. For example, Ga_TwoO_Three, SiO, GeO, G
eO_Two, SnO, SnO_Two, SnSiO_Three, PbO, P
bO_Two, Pb_TwoO_Three, Pb_TwoO_Four, Pb_ThreeO_Four, Sb_Two
O_Three, Sb_TwoO_Four, Sb_TwoO_Five, Bi_TwoO_Three, Bi_TwoO
_Four, Bi_TwoO_Five, SnSiO _Three, GeS, GeS_Two, S
nS, SnS_Two, PbS, PbS_Two, Sb_TwoS_Three, Sb
_TwoS_Five, SnSiS_ThreeAre preferred. Also, these are acid
Complex oxide with lithium bromide, eg Li_TwoGeO_Three, L
i_TwoSnO_TwoIt may be.

It is preferable that the above-mentioned complex chalcogen compound and complex oxide are mainly amorphous when incorporated in a battery. The term “amorphous” as used herein refers to a substance having a broad scattering band having a peak at 20 ° to 40 ° in 2θ value by X-ray diffraction using CuKα ray, and having a crystalline diffraction line. Is also good. Preferably, the strongest intensity among the crystalline diffraction lines observed at 40 ° to 70 ° in 2θ value is 2θ.
It is preferably 500 times or less, more preferably 100 times or less, particularly preferably 5 times or less, and most preferably 5 times or less, as high as the diffraction line intensity at the apex of the broad scattering band seen in a value of 20 ° to 40 °. It is preferable that it has no crystalline diffraction line.

The above complex chalcogen compound and complex oxide are B, Al, Ga, In, Tl, Si, Ge, Sn and P.
It is a complex chalcogen compound or complex oxide of three or more kinds of elements among b, P, As, Sb and Bi, and more preferably a complex oxide. Particularly preferably B, Al, Si, G
It is a composite oxide composed of three or more elements of e, Sn, and P. These complex oxides may contain an element of Group 1 to 3 or a halogen element of the periodic table mainly for modifying the amorphous structure.

Among the above-mentioned negative electrode materials, an amorphous complex oxide containing tin as a main component is particularly preferable and is represented by the following general formula (1). SnM ¹ _a O _t General formula (1) In the formula, M ¹ is two or more selected from Al, B, P, Si, Group 1 element of the periodic table, Group 2 element, Group 3 element, and halogen element. , A is a number of 0.2 or more and 2 or less, and t is a number of 1 or more and 6 or less.

Of the general formula (1), the compound of the following general formula (2) is more preferable. SnM ² _b O _t General formula (2) In the formula, M ² is Al, B, P, a group 1 element of the periodic table, a second group
Represents two or more elements selected from Group 3 elements, Group 3 elements, and halogen elements, b is a number from 0.2 to 2 and t is 1
It represents a number of not less than 6 and not more than 6.

Of the general formula (1), the compound of the following general formula (3) is more preferable. SnM ³ _c M ⁴ _d O _t General formula (3) In the formula, M ³ is at least two kinds of Al, B, P and Si,
M ⁴ is a group 1 element, a group 2 element, a group 3 element of the periodic table,
Represents at least one kind of halogen element, c is a number of 0.2 or more and 2 or less, d is a number of 0.01 or more and 1 or less, and 0.2 <
c + d <2, t represents a number of 1 or more and 6 or less. M ³ and M ⁴
Is an element for amorphizing the compound of the general formula (3) as a whole, M ³ is an element that can be made amorphous, and A 3
It is preferable to use two or more of 1, B, P, and Si in combination. M ⁴ is an element that can be modified to be amorphous, and is a group 1 element, a group 2 element, a group 3 element, or a halogen element of the periodic table, and K, Na, Cs, Mg, Ca, Ba, Y,
F is preferred. b is a number from 0.2 to 2 and c is 0.0
It is a number of 1 or more and 1 or less, 0.2 <b + c <2, and t represents a number of 1 or more and 6 or less.

The amorphous composite oxide of the present invention may employ either a calcination method or a solution method, but the calcination method is more preferable. In the baking method, it is preferable to mix well the oxides or compounds of the elements described in the general formula (1) and then bake to obtain an amorphous composite oxide.

The firing conditions are preferably a temperature raising rate of 5 ° C. or more and 200 ° C. or less per minute, a firing temperature of 500 ° C. or more and 1500 ° C. or less, and a firing time. Is more than 1 hour 10
It is preferably 0 hours or less. And, it is preferable as the descending rate of temperature or less per minute 2 ℃ least 10 ⁷ ° C.. In the present invention, the heating rate is defined as “the firing temperature (° C.)
Is the average rate of temperature rise from "50% of the firing temperature (expressed in ° C)" to "80% of the firing temperature (expressed in ° C)." It is the average rate of temperature drop until it reaches "50% (in ° C)". The temperature may be cooled in a firing furnace, or may be taken out of the firing furnace and put into, for example, water for cooling. Also ceramic processing (Gihodo Publishing 1)
987) Gun method described on page 217, Hammer-An
A super quenching method such as a vil method, a slap method, a gas atomizing method, a plasma spray method, a centrifugal quenching method, and a melt drag method can also be used. Also, the single roller method described in page 172 of the New Glass Handbook (Maruzen 1991),
Cooling may be performed using a twin roller method. In the case of a material that melts during firing, a fired product may be continuously taken out while supplying raw materials during firing. In the case of a material that melts during firing, it is preferable to stir the melt.

The firing gas atmosphere is preferably an atmosphere having an oxygen content of 5% by volume or less, and more preferably an inert gas atmosphere. Examples of the inert gas include nitrogen, argon, helium, krypton, xenon, and the like. The most preferred inert gas is pure argon.

The average particle size of the compound of the present invention is preferably 0.1 to 60 μm. In order to obtain a predetermined particle size, a well-known pulverizer or classifier is used. For example, a mortar, a ball mill, a sand 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. At the time of pulverization, wet pulverization in the presence of water or an organic solvent such as methanol can also be performed as necessary. Classification is preferably performed to obtain a desired particle size. The classification method is not particularly limited, and a sieve, an air classifier, or the like can be used as necessary. Classification can be performed both in a dry type and a wet type.

Examples of the negative electrode material of the present invention are shown below.
The invention is not limited to these. SnB_0.5P
_0.5O_Three, SnAl_0.3B_0.5P_0.2O_2.7, SnAl
_0.3B_0.7O_2.5, SnSi_0.8P_0.2O_3.1, SnS
i_0.8B_0.2O_2.9, SnSi_0.8Al_0.2O_2.9, S
nSi_0.6Al_0.2B_0.2O_2.8, SnSi_0.6Al
_0.2P _0.2O_Three, SnSi_0.6B_0.2P_0.2O_Three, Sn
Si_0.4Al_0.2B_0.4O_2.7, SnSi_0.6Al_0.1
B_0.1P_0.3O_3.25, SnSi_0.6Al_0.1B_0.3P_0.
1O_3.05, SnSi_0.5Al_0.3B_0.4P_0.2O_3.55,
SnSi_0.5Al_0.3B _0.4P_0.5O_4.30, SnSi
_0.8Al_0.3B_0.2P_0.2O_3.85, SnAl_0.1B _0.5
P_0.5Mg_0.1F_0.2O_3.15

SnSi_0.8Mg_0.2O_2.8, SnSi
_0.6Al_0.2Mg_0.2O_2.7, SnSi _0.6Al_0.1B
_0.2Mg_0.2O_2.85, SnSi_0.8Ca_0.2O_2.8, S
nSi_{0. 6}Al_0.2Ca_0.2O_2.7, SnSi_0.6Al
_0.1B_0.1P_0.1Ca_0.2O_2.95, SnSi_0.5Al
_0.2B_0.1P_0.1Mg_0.1O_2.8, SnSi_0.5Al
_0.1B _0.2P_0.1Ca_0.4O_3.1, SnSi_0.8Ba
_0.2O_2.8, SnSi_0.6Al_{0. 1}B_0.1P_0.1Ba
_0.2O_2.95.

Sn_0.9Mn_0.3B_0.4P_0.4Ca_0.1R
b_0.1O_2.95, Sn_0.9Fe_0.3B_{0. Four}P_0.4Ca_0.1
Rb_0.1O_2.95, Sn_0.8Pb_0.2Ca_0.1P_0.9O
_3.35, Sn_0.3Ge_0.7Ba_0.1P_0.9O_3.35, Sn
_0.9Mn_0.1Mg_0.1P_0.9O_3.35, Sn_0.2Mn_0.8
Mg_0.1P_0.9O_3.35, Sn_0.7Pb_0.3Ca_0.1P
_0.9O _3.35, Sn_0.2Ge_0.8Ba_0.1P_0.9O_3.35.

Sn_1.6B_0.4P_0.4Ca_0.2O_3.4, S
n_1.3B_0.4P_0.4Ca_0.2O_3.1, Sn_1.6B_FourP
_0.4Ba_0.2O_3.4, Sn_1.3B_0.4P_0.4Ba_0.2O
_3.1, Sn_1.6B_0.4P_0.4Mg_0.2O_3.4, Sn_1.6
Al_0.1B_0.3P_0.4Ca_0.2O _3.4,

Sn_1.3Al_0.1B_0.3P_0.4K
_0.2O_Three, Sn_1.0Al_0.1B_0.3P_0.4K
_{0. Two}O_2.7, Sn_1.6Al_0.1B_0.3P_0.4Na_0.2O
_3.3, Sn_1.3Al_0.1B _0.3P_0.4Na_0.2O_Three, S
n_1.0Al_0.1B_0.3P_0.4Na_0.2O_2.7, Sn _1.6
Al_0.1B_0.3P_0.4Rb_0.2O_3.3, Sn_1.3Al
_0.1B_0.3P_0.4Rb _0.2O_Three, Sn_1.0Al_0.1B
_0.3P_0.4Rb_0.2O_2.7, Sn_1.6Al_0.1B _0.3P
_0.4Cs_0.2O_3.3, Sn_1.2Al_0.1B_0.3P_0.4C
s_0.2O_2.9, Sn_1.0Al_0.1B_0.3P_0.4Cs_0.2
O_2.7, Sn_1.3Al_0.1B_0.3P_0.4Ba_0.1K_0.1
O_3.05.

The chemical formula of the compound obtained by firing can be calculated by an inductively coupled plasma (ICP) emission spectroscopy as a measuring method, and as a simple method from the weight difference between the powders before and after firing.

The amount of the light metal inserted into the negative electrode material of the present invention may be close to the deposition potential of the light metal.
The amount is preferably from 50 to 700 mol%, more preferably from 100 to 600 mol%, per negative electrode material. It is preferable that the release amount be larger than the insertion amount. How to insert light metal
Electrochemical, chemical and thermal methods are preferred. As the electrochemical method, a method of electrochemically inserting a light metal contained in the positive electrode active material or a method of directly electrochemically inserting a light metal or an alloy thereof from a light metal is preferable. As a chemical method, there is a method of mixing or contacting with a light metal or a method of reacting with an organic metal such as butyllithium. Electrochemical and chemical methods are preferred. The light metal is particularly preferably lithium or lithium ion.

Various elements can be contained in the negative electrode material of the present invention. For example, lanthanoid metals (Hf, T
a, W, Re, Os, Ir, Pt, Au, Hg) and various compounds that increase electron conductivity (for example, Sb, In, N
b) may be included. The amount of the compound to be added is preferably 0 to 5 mol%.

The oxide positive electrode active material used in the present invention
Alternatively, the surface of the negative electrode material can be
Can be coated with oxide with different chemical formula from material
You. This surface oxide dissolves both acidic and alkaline
The oxide containing the compound is preferable. More electronically conductive
High metal oxides are preferred. For example, PbO_Two, Fe _Two
O_Three, SnO_Two, In_TwoO_Three, ZnO, etc. or this
These oxides have dopants (eg
It is preferable to include different metals, halogen elements, etc.)
New Particularly preferably, SiO 2_Two, SnO_Two, Fe_TwoO
_Three, ZnO and PbO. Used for these surface treatments
The amount of the metal oxide used depends on the amount of the positive electrode active material and the negative electrode material.
0.1 to 10% by weight is preferable, 0.2 to 5% by weight
Is particularly preferable, and 0.3 to 3% by weight is the most preferable. Ma
In addition to this, the surface of the positive electrode active material and negative electrode material is modified.
Can be For example, ester the surface of metal oxide
Treatment with an agent, treatment with a chelating agent, conductive polymer,
Treatment with polyethylene oxide etc.
Can be

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. Preferred lithium-containing transition metal oxide positive electrode active materials used in the present invention include lithium-containing Ti, V, Cr, M
An oxide containing n, Fe, Co, Ni, Cu, Mo, and W can be used. Alkali metals other than lithium (elements IA and IIA of the periodic table), and / or Al, Ga,
In, Ge, Sn, Pb, Sb, Bi, Si, P, B, etc. may be mixed. The mixing amount is 0 to 3 with respect to the transition metal.
0 mol% is preferred. More preferred lithium-containing transition metal oxide cathode active materials used in the present invention include lithium compounds / transition metal compounds (where the transition metal is T
i, V, Cr, Mn, Fe, Co, Ni, Mo, W, at least one of them) in a total molar ratio of 0.3 to
It is preferable to synthesize them by mixing them to 2.2.
Particularly preferred lithium-containing transition metal oxide positive electrode active materials for use in the present invention include lithium compounds / transition metal compounds (where transition metals are V, Cr, Mn, F
It is preferable to synthesize them by mixing them so that the total molar ratio of at least one selected from e, Co, and Ni) is 0.3 to 2.2. Particularly preferred lithium-containing transition metal oxide cathode active materials used in the present invention are Lix QO
y (where Q is mainly at least one of Co,
Transition metal containing Mn, Ni, V, Fe), x = 0.2 to
1.2, y = 1.4-3). As Q, other than transition metals, Al, Ga, In, Ge, Sn,
Pb, Sb, Bi, Si, P, B and the like may be mixed. The mixing amount is preferably 0 to 30 mol% with respect to the transition metal.

Further preferred Lithiu used in the present invention
Li-containing metal oxide positive electrode active materials include Li_xCo
O_Two, Li_xNiO_Two, Li_xMnO_Two, Li_xCo_a
Ni_1-aO_Two, Li_zCo_bV_1-bO_z, Li_xCo_b
Fe_1-bO_Two, Li_xMn_TwoO_Four, Li_xMn_cCo
_2-cO_Four, Li_xMn_cNi_2-cO_Four, Li_xMn_cV
_2-cO_z, Li_xMn_cFe_2-cO_Four, Li_xCo_bB
_1-bO_Two, Li_xCo_bSi _1-bO_Two, Li_xMn_TwoO
_FourAnd MnO_TwoMixture of Li_2xMnO_ThreeAnd MnO_TwoBlend of
Compound, Li_xMn_TwoO_Four, Li_2xMnO_ThreeAnd MnO_Twoof
Mixture (where x = 0.2-1.2, a = 0.1-0.
9, b = 0.8 to 0.98, c = 1.6 to 1.96, z
= 2.01-5). Used in the present invention
More preferred lithium-containing metal oxide positive electrode active material
Is Li_xCoO_Two, Li_xNiO_Two, Li_xMn
O_Two, Li_xCo_aNi_1-aO_Two, Li_xCo_bV_1-b
O_z, Li_xCo_bFe_1-bO_Two, Li_xMn_TwoO_Four,
Li_xMn_cCo_2-cO_Four, Li_xMn_cNi
_2-cO_Four, Li_xMn_cV_2-cO_Four, Li_xMn_cFe
_2-cO_Four(Where x = 0.7 to 1.2, a = 0.1
0.9, b = 0.8 to 0.98, c = 1.6 to 1.9
6, z = 2.01 to 2.3). For use in the present invention
Most preferred lithium-containing transition metal oxide positive electrode
As the active material, Li_xCoO_Two, Li_xNiO_Two, L
i_xMnO_Two, Li_xCo_aNi_{1- a}O_Two, Li_xMn
_TwoO_Four, Li_xCo_bV_1-bO_z(Where x = 0.7-
1.2, a = 0.1 to 0.9, b = 0.9 to 0.98,
z = 2.02-2.3). Where the above
The x value is the value before the start of charging / discharging and increases / decreases due to charging / discharging.
You.

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 decomposes and melts.
50-2000 ° C is preferred, and especially 350-1500 ° C
Is preferred. In firing, it is preferable to calcine at 250 to 900 ° C. The firing time is preferably from 1 to 72 hours, more preferably from 2 to 20 hours. The mixing method of the raw materials may be dry or wet. After firing, 20
Annealing may be performed at 0 ° C. to 900 ° C. The firing gas atmosphere is not particularly limited, and may be an oxidizing atmosphere or a reducing atmosphere. For example, in air, or a gas whose oxygen concentration is adjusted to an arbitrary ratio, or hydrogen, carbon monoxide,
Examples include nitrogen, argon, helium, krypton, xenon, and carbon dioxide.

In synthesizing the positive electrode active material of the present invention, as a method of chemically inserting lithium ions into a transition metal oxide, a lithium metal, a lithium alloy, or butyl lithium is reacted with the transition metal oxide to synthesize. The method 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.
The specific surface area is not particularly limited.
It is preferably from 01 to 50 m ² / g. The pH of the supernatant when 5 g of the positive electrode active material is dissolved in 100 ml of distilled water is preferably 7 or more and 12 or less. In order to obtain a predetermined particle size, a well-known pulverizer or classifier is used. For example, a mortar, a ball mill, a vibrating ball mill, a vibrating mill, a satellite ball mill, a planetary ball mill, a swirling air jet mill, a sieve, and the like are used. The positive electrode active material obtained by firing may be used after being washed with water, an acidic aqueous solution, an alkaline aqueous solution, or an organic solvent.

Anode material and cathode active material used in the present invention
Is preferably represented by the general formula (1)
Compound and Li_xCoO_Two, Li_xNiO_Two, Li_xCo
_aNi_1-aO_Two, Li_xMnO_Two, Li_xMn_TwoO_Four,
Or Li_xCo_bV_1-bO _z(Where x = 0.7-
1.2, a = 0.1 to 0.9, b = 0.9 to 0.98,
z = 2.02-2.3), and high discharge
Non-aqueous secondary battery with high voltage, high capacity and excellent charge / discharge cycle characteristics
You can get a pond.

The equivalent amount of lithium inserted into the negative electrode material of the present invention is 3 to 10 equivalents, and the amount ratio with the positive electrode active material is determined according to this equivalent amount. It is preferable to multiply the usage ratio based on this equivalent by a factor of 0.5 to 2 times. When the lithium supply source is other than the positive electrode active material (for example, lithium metal, alloy, butyl lithium, etc.), the amount of the positive electrode active material used is determined according to the lithium release equivalent of the negative electrode material. Also in this case, it is preferable to multiply the used amount ratio based on this equivalent by a factor of 0.5 to 2 times.

When lithium is inserted into the negative electrode from a lithium supply source other than the positive electrode in advance, lithium metal, lithium alloy (Al, Al-Mn,
It is preferable to use foil or metal powder of Al-Mg, Al-Sn, Al-In, or an alloy of Al-Cd and lithium.
These metal foils and the like may be located directly on the negative electrode mixture or via the protective layer of the present invention. Further, it may be located on a current collector without a negative electrode mixture. As the foil, a thin foil having a thickness of about 20 μm may be applied uniformly, or a thicker foil may be partially arranged. The thickness of the foil can be determined from the amount that is naturally inserted into the negative electrode after battery formation.

A conductive agent, a binder, a filler and the like can be added to the electrode mixture. The conductive agent may be any electronic conductive material that does not cause a chemical change in the configured battery. Usually, natural graphite (flaky graphite, flaky graphite, earthy graphite, etc.), artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber and metal (copper, nickel, aluminum, silver, etc.) powder, metal Conductive materials such as fibers or polyphenylene derivatives
It can be included as a seed or a mixture thereof.
A combination of graphite and acetylene black is particularly preferred. The addition amount is preferably 1 to 50% by weight, particularly 2 to 30% by weight.
% By weight is preferred. For carbon and graphite, 2 to 15% by weight is particularly preferred.

The binder is usually starch, polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, regenerated cellulose, diacetyl cellulose, polyvinyl chloride, polyvinyl pyrrolidone,
Tetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, ethylene-propylene-diene terpolymer (EPDM), sulfonated EPDM, styrene butadiene rubber, polybutadiene, fluoro rubber,
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, for example, it is preferable to add a compound such as an isocyanate group to deactivate the functional group. The amount of the binder added is preferably 1 to 50% by weight, particularly 2 to 30% by weight.
Is preferred. As the filler, any fibrous material that does not cause a chemical change in the configured battery can be used. Usually, fibers such as olefin-based polymers such as polypropylene and polyethylene, glass, and carbon are used. Although the amount of the filler is not particularly limited,
-30% by weight is preferred.

When the negative electrode material of the present invention is used in a non-aqueous secondary battery system, an aqueous dispersion mixture paste containing the compound of the present invention is applied on a current collector and dried, and the aqueous dispersion mixture paste is used. It is preferable that the pH is 5 or more and less than 10, more preferably 6 or more and less than 9. Further, it is preferable that the temperature of the aqueous dispersion paste is maintained at 5 ° C. or higher and lower than 80 ° C., and the application on the current collector is performed within 7 days after the preparation of the paste.

As the separator, a material having a large ion permeability, a predetermined mechanical strength, and an insulating micropore or a gap is used. In order to further improve safety, it is necessary to have a function of closing the above gap at 80 ° C. or higher to increase resistance and cut off current. The closing temperature of these gaps is from 90 ° C to 180 ° C, more preferably from 110 ° C to 170 ° C. The method of forming the gap differs depending on the material, but may be any known method. In the case of a porous film, the shape of the holes is usually circular or elliptical, and the size is 0.05 μm to 30 μm, preferably 0.1 μm to 20 μm. Further, as in the case of the drawing method or the phase separation method, the holes may be rod-shaped or amorphous. In the case of cloth, the gap is a space between fibers, and depends on how to make a woven or nonwoven fabric. The ratio of closing of these gaps, that is, the porosity is from 20% to 90%,
35% to 80% is preferred.

The separator of the present invention has a thickness of 5 μm or more and 10
It is a microporous film, woven fabric, nonwoven fabric or the like having a thickness of 0 μm or less, more preferably 10 μm or more and 80 μm or less.
The separator of the present invention contains at least 2 ethylene components.
0% by weight is preferable, and 30% is particularly preferable.
The above is included. Examples of components other than ethylene include propylene, butene, hexene, fluorinated ethylene, vinyl chloride, vinyl acetate, and acetalized vinyl alcohol, and propylene and fluorinated ethylene are particularly preferable.
The microporous film is preferably made of polyethylene, an ethylene-propylene copolymer or an ethylene-butene copolymer. Further, those made by mixing and dissolving polyethylene and polypropylene and polyethylene and polytetrafluoroethylene are also preferable. Non-woven fabrics and woven fabrics are
The diameter of the thread is 0.1 μm to 5 μm, and polyethylene, ethylene-propylene copolymer, ethylene-butene 1
A polymer comprising a copolymer, an ethylene-methylbutene copolymer, an ethylene-methylpentene copolymer, polypropylene, and polytetrafluoroethylene fiber yarn is preferable. These separators may be a single material or a composite material. In particular, two or more types of microporous films laminated with different pore sizes, porosities and pore blocking temperatures, microporous films and non-woven fabrics, microporous films and woven fabrics, and non-woven fabrics and papers with different forms of composite materials. What was done is especially preferable. The separator of the present invention may contain inorganic fibers such as glass fibers and carbon fibers, and particles of inorganic substances such as silicon dioxide, zeolite, alumina and talc. Further, the voids and the surface may be treated with a surfactant to make them hydrophilic.

As the electrolyte, propylene is used as the organic solvent.
Lencarbonate, ethylene carbonate, butyleneca
-Carbonate, dimethyl carbonate, diethyl carbonate
, Gamma-butyrolactone, 1,2-dimethoxy eta
, Tetrahydrofuran, 2-methyltetrahydrofuran
Dimethyl sulfoxide, 1,3-dioxolane,
Formamide, dimethylformamide, dioxolan,
Acetonitrile, nitromethane, methyl formate, methyl acetate
, Methyl propionate, ethyl propionate, phosphoric acid
Triester, trimethoxymethane, dioxolane derivatives
Body, sulfolane, 3-methyl-2-oxazolidinone,
Propylene carbonate derivative, tetrahydrofuran derivative
Conductor, diethyl ether, 1,3-propane sultone
Mix at least one of any aprotic organic solvents
Solvent and a lithium salt soluble in the solvent, for example, Li
ClO_Four, LiBF_Four, LiPF₆, LiCF_ThreeS
O_Three, LiCF_ThreeCO_Two, LiAsF₆, LiSb
F₆, LiB_TenCl_Ten, Lower aliphatic carboxylic acid lithium
System, LiAlCl_Four, LiCl, LiBr, LiI,
Such as lithium loroborane and lithium tetraphenylborate
It is composed of one or more salts. Above all,
Carbonate or ethylene carbose and 1,2-diene
Methoxyethane and / or diethyl carbonate
LiCF in the mixed solution of_ThreeSO _Three, LiClO_Four, LiBF
_FourAnd / or LiPF₆Electrolyte solution containing
No. Mixed solution of ethylene carbonate and diethyl carbonate
To LiBF_FourAnd / or LiPF₆Electrolyte containing
Is particularly preferred. Amount of these electrolytes added to the battery
Is not particularly limited, but the amount of the positive electrode active material and the negative electrode material,
The required amount can be used depending on the size of the battery. support
The concentration of the electrolyte is 0.2 to 3 m / l of the electrolytic solution.
Are preferred.

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. Well-known inorganic solid electrolytes include nitrides, halides, and oxyacid salts of Li. Among them, Li ₃ N, LiI, Li ₅ N
_{I 2, Li 3 N-LiI} -LiOH, LiSiO 4, L
iSiO ₄ —LiI—LiOH, xLi ₃ PO ₄ — (1
-X) Li ₄ SiO ₄ , Li ₂ SiS ₃ , phosphorus sulfide compounds and the like are effective. In the organic solid electrolyte, a polyethylene oxide derivative or a polymer containing the derivative, a polypropylene oxide derivative or a polymer containing the derivative,
A polymer containing an ion-dissociating group, a mixture of the polymer containing an ion-dissociating group and the above-mentioned aprotic electrolyte, and a phosphate polymer are effective. Furthermore, there is a method of adding polyacrylonitrile to the electrolytic solution. In addition, a method of using an inorganic and an organic solid electrolyte in combination is also known.

As the separator, an insulating thin film having a large ion permeability and a predetermined mechanical strength is used. Sheets or nonwoven fabrics made of olefin polymers such as polypropylene or glass fibers or polyethylene are used because of their resistance to organic solvents and hydrophobicity. The pore size of the separator is in a range generally used for batteries. For example, 0.01-10 μ
m is used. The thickness of the separator is generally used in the range for batteries. For example, a thickness of 5 to 300 μm is used. It is known that the following compounds are added to an electrolyte for the purpose of improving discharge and charge / discharge characteristics. For example, pyridine, triethyl phosphite, triethanolamine, cyclic ether, ethylenediamine, n-
Glyme, hexaphosphoric triamide, nitrobenzene derivative, sulfur, quinone imine dye, N-substituted oxazolidinone and N, N'-substituted imidazolidinone, ethylene glycol dialkyl ether, quaternary ammonium salt, polyethylene glycol, pyrrol, 2-methoxyethanol
, AlCl ₃ , monomer of conductive polymer electrode active material, triethylene phosphoramide, trialkylphosphine, morpholine, aryl compound having carbonyl group, hexamethylphosphoric triamide and 4-alkylmorpholine Tertiary amines, bicyclic tertiary amines, oils (JP-A-62-287580), quaternary phosphonium salts, tertiary sulfonium salts and the like.

Further, in order to make the electrolyte nonflammable, a halogen-containing solvent such as carbon tetrachloride or ethylene trifluoride chloride can be contained in the electrolyte. In addition, carbon dioxide gas can be included in the electrolytic solution in order to provide suitability for high-temperature storage. Further, the mixture of the positive electrode and the negative electrode can contain an electrolytic solution or an electrolyte. For example, a method is known in which the ion-conductive polymer, nitromethane, and an electrolyte are included.

The positive and negative electrode current collectors may be any electron conductors that do not undergo a chemical change in the constructed battery. For example, for the positive electrode, stainless steel,
In addition to nickel, aluminum, titanium, carbon, etc., carbon, nickel,
What processed titanium or silver is used. Particularly, aluminum or an aluminum alloy is preferable. For the negative electrode, stainless steel, nickel,
In addition to copper, titanium, aluminum, carbon, and the like, copper, stainless steel, which is obtained by treating carbon, nickel, titanium, or silver on the surface, an Al—Cd alloy, or the like is used. Particularly, copper or a copper alloy is preferable. Oxidizing the surface of these materials is also used. In addition, it is desirable to make the current collector surface uneven by surface treatment. As the shape, in addition to a foil, a film, a sheet, a net, a punched material, 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.
Those having a thickness of up to 500 μm are used.

The shape of the battery can be any of coins, buttons, sheets, cylinders, flats, 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 material is mainly used after being compressed into a pellet shape.
The thickness and diameter of the pellet are determined by the size of the battery. When the shape of the battery is a sheet, a cylinder, or a corner, the mixture of the positive electrode active material and the negative electrode material is mainly used after being applied (coated), dried, and compressed on the current collector. As a coating method, a general method can be used. For example,
Reverse roll method, direct roll method, blade method,
Knife method, extrusion method, curtain method, gravure method, bar method, dip method and squeeze method can be mentioned. Among them, a blade method, a knife method and an extrusion method are preferred. Application is 0.1-10
It is preferably carried out at a speed of 0 m / min. On this occasion,
By selecting the above-mentioned coating method in accordance with the solution physical properties and drying property of the mixture, a good surface state of the coated layer can be obtained. The coating may be performed on one side at a time or on both sides simultaneously. The application may be continuous, intermittent, or striped. The thickness, length and width of the coating layer are determined according to the size of the battery, and the thickness of the coating layer on one side is particularly preferably 1 to 2000 μm in a compressed state after drying.

As a method for drying or dehydrating the pellets or sheets, a generally adopted method can be used. In particular, it is preferable to use hot air, vacuum, infrared rays, far-infrared rays, electron beams and low-humidity air alone or in combination. The temperature is preferably in the range of 80 to 350 ° C, particularly 10 ° C.
A range from 0 to 250 ° C is preferred. The water content of the entire battery is preferably 2000 ppm or less, and the positive electrode mixture, the negative electrode mixture and the electrolyte are each preferably 500 ppm or less from the viewpoint of cycleability. As a method for pressing pellets and sheets, a method generally used can be used, but a die pressing method and a calendar pressing method are particularly preferable. The pressing pressure is not particularly limited, but is 0.2 to 3 t /
cm ² is preferred. The press speed of the calender press method is preferably from 0.1 to 50 m / min, and the press temperature is from room temperature to 2 m / min.
00 ° C is preferred. The ratio of the width of the negative electrode sheet to the width of the negative electrode sheet is preferably 0.9 to 1.1, and particularly preferably 0.95 to 1.0. The content ratio between the positive electrode active material and the negative electrode material varies depending on the compound type and the mixture formulation, and thus cannot be limited. However, it can be set to an optimal value from the viewpoint of capacity, cycleability, and safety.

Stacked with the mixture sheet via a separator
After fitting, the sheets are rolled or folded
After inserting the can and the sheet electrically,
The liquid is injected, and a battery can is formed using the sealing plate. this
Sometimes, a safety valve can be used as a sealing plate. safety valve
In addition, equipped with various conventionally known safety elements
May be. For example, fuses,
A bimetal, a PTC element, or the like is used. Also safe
In addition to the valve, cut off the battery
Method, gasket cracking method or sealing plate turtle
It is possible to use a splitting method or a cutting method with a lead plate.
it can. In addition, overcharge and overdischarge measures are incorporated in the charger.
With a protection circuit or connected independently
Is also good. In addition, as a measure against overcharging,
A method of interrupting the current. This and
The compound or electrolyte to increase the internal pressure
Can be Of compounds used to increase internal pressure
For example, Li_TwoCO _Three, LiHCO_Three, Na_TwoCO
_Three, NaHCO_Three, CaCO_Three, MgCO_ThreeSuch as carbonic acid
Salts and the like can be mentioned.

For the can and the lead plate, a metal or alloy having electrical conductivity can be used. For example, metals such as iron, nickel, titanium, chromium, molybdenum, copper, and aluminum or alloys thereof are used. Caps, cans,
Known methods (eg, DC or AC electric welding, laser welding, ultrasonic welding) can be used for welding the sheet and the lead plate. A conventionally known compound or mixture such as asphalt can be used as the sealing agent for closing.

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 computer. 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,
Examples include a transceiver, a power tool, an electronic organizer, a calculator, a memory card, a tape recorder, a radio, a backup power supply, and a memory card. For other consumer use, automobiles, electric vehicles, motors, lighting equipment, toys,
Game devices, road conditioners, irons, watches, strobes, cameras, medical devices (pacemakers, hearing aids, shoulder massagers, etc.). Furthermore, it can be used for various military purposes and space applications. Further, it can be combined with a solar cell.

[0057]

The present invention will be described in more detail with reference to specific examples, but the present invention is not limited to the examples unless it exceeds the gist of the invention.

Synthesis Example-1 Tin monoxide (13.5 g), silicon dioxide (3.6 g), magnesium oxide (0.64 g) and boron oxide (0.69 g) were dry-mixed, placed in an alumina crucible and placed under an argon atmosphere at 15 ° C.
The temperature was raised to 1000 ° C./min. After firing at 1200 ° C. 10 h, then cooled to room temperature at 10 ° C. / min, taken out from the firing furnace, which was roughly pulverized, and further pulverized with a jet mill, SnSi an average particle size of 4.5 [mu] m _{0. 6} Mg _0.2 B
_0.2 O _2.7 (Compound 1-A) was obtained. The X-ray diffractometry using CuKα rays has a broad peak having a peak at a 2θ value of about 28 °, and a crystalline diffraction line is observed at a 2θ value of 40 ° to 70 °. There wasn't.

In a similar manner, each stoichiometric amount of raw material
Were mixed, fired and pulverized to obtain the following compound. SnSi
_0.8Mg_0.2O_2.8(1-B), SnSi_0.6Al_0.2
Mg _0.2O_2.7(1-C), SnSi_0.6P_0.2Mg
_0.2O_2.9(1-D), SnSi_0.6Al_0.1B_0.2M
g_0.1O_2.75(1-E), SnSi_0.5P_0.1B_0.1M
g_0.3O_2.7(1-F).

Example-1 As the negative electrode material, the compound 1-A synthesized in Synthesis Example-1 was used, mixed at a ratio of 88% by weight and 6% by weight of flake graphite, and further used as a binder. 4% by weight of an aqueous dispersion of vinylidene chloride, 1% by weight of carboxymethylcellulose and 1% by weight of lithium acetate were added and kneaded with water as a medium to prepare a slurry. The thickness of the slurry is 18μ
A negative electrode a was prepared by applying the copper foil of m on both sides by the extrusion method. The negative electrode b is the α-A on the negative electrode a.
97% by weight of 1 ₂ O ₃ (average particle size 1 μm) and 3% by weight of carboxymethyl cellulose were mixed, and kneaded with water as a medium to form a slurry, which was applied to prepare. These negative electrodes a and b were dried, compression-molded by a calender press, and cut into a predetermined width and length to produce strip-shaped negative electrode sheets a and b, respectively. The thickness of the negative electrode sheet is
The negative electrode sheet a was 78 μm, and the negative electrode sheet b was 100 μm. 87% by weight of LiCoO ₂ as a positive electrode material,
6% by weight of scaly graphite, 3% by weight of acetylene black, 3% by weight of polytetrafluoroethylene aqueous dispersion as a binder and 1% by weight of sodium polyacrylate were added,
The slurry obtained by kneading with water as a medium has a thickness of 20μ.
Apply to both sides of aluminum foil of m by the same method as above,
A positive electrode a was made. The positive electrode b is formed on the positive electrode a by α-Al ₂
It was prepared by mixing 97% by weight of O ₃ (average particle size 1 μm) and 3% by weight of carboxymethyl cellulose, kneading with water as a medium to form a slurry, and applying the mixture. These positive electrodes, a and b are dried, pressed and cut to obtain a positive electrode sheet,
Made a and b. The thickness of the positive electrode sheet was 250 μm for the positive electrode sheet a and 265 μm for the positive electrode sheet b. Negative electrode sheet a and positive electrode sheet a, negative electrode sheet b and positive electrode sheet b
And a battery A (for comparison) and a battery B (present invention) were produced by the method described below. Nickel and aluminum lead plates were spot-welded to the respective ends of the negative electrode sheet and the positive electrode sheet, and then dehydrated and dried at 150 ° C. for 2 hours in dry air having a dew point of −40 ° C. or less. Furthermore, the dehydrated and dried positive electrode sheet (8), a microporous polypropylene film separator (Celgard 2400),
Dehydrated and dried negative electrode sheet (9) and separator (1
0) were laminated in this order, and this was spirally wound with a winding machine.

This wound body was housed in a nickel-plated iron bottomed cylindrical battery can (11) which also served as a negative electrode terminal. LiPF ₆ and LiBF ₄ are 0.9 per 1 L, respectively.
An electrolyte containing 5 and 0.05 mol of a solvent and a solvent of ethylene carbonate and diethyl carbonate in a volume ratio of 2: 8 was injected into a battery can. Battery cover with positive terminal (1
2) was caulked through a gasket (13) to produce a cylindrical battery. The positive electrode terminal (12) was connected to the positive electrode sheet (8), and the battery can (11) was connected to the negative electrode sheet (9) by a lead terminal in advance. FIG. 1 shows a cross section of a cylindrical battery. Incidentally, (14) is a safety valve. Battery A
(Comparative) and Battery B (invention) were prepared in units of 10 and charged at 1 mA / cm ² to 4.15 V, then 60
It was stored at 0 ° C for 3 weeks. After 3 weeks, the open circuit voltage of each battery was measured and the following results were obtained. Battery number Battery A (comparative battery) Battery B (battery of the invention) open circuit voltage open circuit voltage 1 0.92 4.12 2 1.02 4.10 3 1.00 4.08 4 0.78 4.09 5 0.98 4.11 6 1.12 4.13 7 1.03 4.11 8 0.91 4.08 9 0.81 4.09 10 0.54 4.11 From the above results, It can be seen that the battery clearly has a small voltage drop during storage and has stable performance.

Example 2 300 batteries each of which were the same as the batteries A and B of Example 1 were prepared and charged to 4.15V. When the number of batteries with poor charging was determined, it was 6 for the comparative battery A and 0 for the battery B of the present invention, and it was found that the defective product rate was clearly improved.

Example 3 Instead of the negative electrode material 1-A used in Example 1, 1-B was used.
When an experiment similar to that of Example-1 was conducted using 1 to 1-F, almost the same results as in Example-1 were obtained. Example-4 A battery C was made by combining the negative electrode sheet b and the positive electrode sheet a of Example-1. Instead of the positive electrode sheet b, the thickness of the protective layer was changed and the positive electrode sheet c and the negative electrode sheet a having a sheet thickness of 280 μm were combined to form a battery D. When an experiment similar to that of Example 1 was conducted using these batteries C and D, it was found that the voltage drop after storage was small and the performance was stable as in the battery B. However, the open circuit voltage of both C and D was slightly lower than that of the battery B. Example-5 On the negative electrode a of Example-1, α-Al ₂ O ₃ (average particle size 1 μm
m) A negative electrode c was prepared by mixing 94% by weight, 3% by weight of flake graphite and 3% by weight of carboxymethyl cellulose, kneading with water as a medium to form a slurry, and applying the mixture. Battery B except that c is used for the negative electrode sheet
The batteries produced in the same manner as in (1) were designated as E. When an experiment similar to that of Example-1 was performed using the battery E, almost the same result as that of Example-1 was obtained. Example-6 On the negative electrode a of Example-1, α-Al ₂ O ₃ (average particle size 1 μm
m) 94.5% by weight, 4.5% by weight of polyvinylidene fluoride, and 1% by weight of carboxymethyl cellulose were mixed, and a mixture prepared by kneading with water as a medium to form a slurry was applied as a negative electrode d. did. A battery prepared in the same manner as the battery B except that d was used for the negative electrode sheet was designated as F.
Example -1 of the battery B, the battery E of Example -5, respectively a battery F was produced ten increments, discharge at 5 mA / cm ² when charged with 4.15-2.8V capacity and 1 mA / cm ² The discharge capacity was measured and the following results were obtained. The discharge capacity in the table is shown as a ratio when the capacity of Battery B is 100%. Discharge capacity of 5 mA / cm ² / Discharge capacity of 1 mA / cm ² Battery B Battery E Battery F 1 88 88 89 81 2 87 87 89 82 3 90 90 89 82 4 88 90 82 5 5 89 89 81 6 88 88 90 82 7 88 88 80 80 89 88 82 9 88 88 89 82 10 88 88 89 82 1mA / cm ² discharge capacity average 100 101 89 From the above results, it is clear that the battery of the present invention has a large capacity and a discharge capacity of 5mA / cm ² / 1mA / cm ² It can be seen that the discharge capacity is excellent. Example-7 On the negative electrode a of Example-1, α-Al ₂ O ₃ (average particle size 1 μm
m) 93% by weight, flake graphite 3% by weight, polyvinylidene fluoride 3% by weight, carboxymethyl cellulose 1% by weight
The negative electrode d was prepared by mixing and mixing at a ratio of 1, 2, and kneading with water as a medium to form a slurry. Also,
In the same manner as the positive electrode a of Example-1, only the coating amount was reduced to form a positive electrode having a thickness of 225 μm, which was provided with the same protective layer as the positive electrode b to form a positive electrode d. 120 mg per 1 g of the negative electrode material on the negative electrode sheet c and the negative electrode sheet d of Example-5.
The positive electrode sheet d is formed by pasting the lithium metal in a strip shape and pasting it.
Batteries produced in the same manner as battery B except that the above were combined were designated as batteries G and H, respectively. Ten of each of these were produced, and the same test as in Example-6 was conducted to obtain the following results.
The discharge capacity in the table is shown as a ratio when the capacity of Battery G is 100%. From the above results, the battery of the present invention is obviously a large capacity, it is excellent in the discharge capacity of the discharge capacity / 1 mA / cm ² of 5 mA / cm ^2.

[0064]

INDUSTRIAL APPLICABILITY As in the present invention, in a non-aqueous secondary battery comprising a positive electrode and a negative electrode containing a material capable of reversibly inserting and extracting lithium, a non-aqueous electrolyte containing a lithium salt, and a separator, Alternatively, the solid particles and the water-soluble polymer are added to the positive electrode.
By providing at least one protective layer consisting of, a non-aqueous secondary battery having a high discharge operating voltage, a large discharge capacity and storage stability can be stably produced.

[Brief description of the drawings]

FIG. 1 is a sectional view of a cylindrical battery used in Examples.

[Explanation of symbols]

 8 Positive electrode sheet 9 Negative electrode sheet 10 Separator 11 Battery can 12 Battery lid 13 Gasket 14 Safety valve

Claims (12)

[Claims] 1. A non-aqueous secondary battery comprising a positive electrode and a negative electrode containing a material capable of reversibly occluding and releasing lithium, a non-aqueous electrolyte containing a lithium salt, and a separator, wherein the negative electrode and / or the positive electrode is a protective layer. A non-aqueous secondary battery having at least one layer of: and the protective layer comprising solid particles and a water-soluble polymer. 2. A non-aqueous secondary battery comprising a positive electrode and a negative electrode containing a material capable of reversibly occluding and releasing lithium, a non-aqueous electrolyte containing a lithium salt, and a separator, wherein the negative electrode and / or the positive electrode is a protective layer. A non-aqueous secondary battery having at least one layer of: and the protective layer comprising solid particles, conductive particles, and a water-soluble polymer. 3. The non-aqueous secondary battery according to claim 1, wherein the protective layer has a thickness of 1 μm or more and 40 μm or less. 4. The non-aqueous secondary battery according to claim 3, wherein the protective layer is formed on the negative electrode. 5. The non-aqueous secondary battery according to claim 3, wherein the protective layer is formed on the positive electrode. 6. The non-aqueous secondary battery according to claim 3, wherein the protective layer is formed on both the positive electrode and the negative electrode. 7. The non-aqueous secondary battery according to claim 3, wherein the protective layer does not contain conductive particles on the positive electrode and contains conductive particles on the negative electrode. 8. The solid particles contained in the protective layer are inorganic chalcogenide particles.
The non-aqueous secondary battery according to any one of the above items. 9. The non-aqueous liquid electrolyte according to claim 8, wherein the inorganic chalcogenide particles contain at least one kind of oxides of sodium, potassium, magnesium, calcium, strontium, zirconium, aluminum and silicon. Next battery. 10. The non-aqueous secondary battery according to claim 9, wherein the oxide of claim 9 is alumina, silicon dioxide, or zirconia. 11. The non-aqueous secondary battery according to claim 8, wherein the water-soluble polymer contained in the protective layer is a polyacrylic acid derivative or a cellulose derivative. 12. The non-aqueous secondary battery according to claim 11, wherein the conductive particles contained in the protective layer are a carbon material.