JPH09237623A - Nonaqueous electrolyte secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain excellent cycle characteristics while keeping a large capacity by containing N-metylpyrolidone(NMP) in a positive electrode and/or a negative electrode in a specific ratio. SOLUTION: A positive electrode and/or a negative electrode contains 50-500ppm (based on a weight of the electrode) of NMP. The NMP is a solvent capable of dissolving a binder and excellent by dispersing a positive and a negative electrode active substance. The NMP contained in an appropriate quantity (50-500ppm) in the electrode acts on interfaces between the active substances and the binder, whereby wettability of both the interfaces can be enhanced. With such an advantageous result, it is possible to provide a battery having a large capacity and being excellent in cycle characteristics. If a quantity of the NMP contained in the electrode is less than 50ppm, the advantageous result is so good; and if more than 500ppm, a strength of an electrode coating becomes small or a phenomenon such as a small capacity occurs since the NMP is mixed into an electrolyte in a large quantity.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a non-aqueous electrolyte secondary battery.

[0002]

2. Description of the Related Art Recent advances in miniaturization, thinning, and weight reduction of electronic devices have been remarkable, and in the OA field, in particular, desktop devices have been reduced in size and weight to laptop types and notebook types. In addition, the field of new small electronic devices such as electronic notebooks and electronic still cameras will also appear, and in addition to the miniaturization of conventional hard disks and floppy disks, the development of new small memory media, memory cards, will be promoted. ing. In the wave of miniaturization, thinning, and weight reduction of such electronic devices, high performance is also required for secondary batteries that support these electric powers. In such a demand, development of a lithium secondary battery as a high energy density battery which replaces a lead battery or a nickel-cadmium battery has been rapidly promoted. Examples of positive electrode active materials for lithium secondary batteries include TiS ₂ , MoS ₂ , CoO ₂ , and V _2.
There are transition metal oxides such as O ₅ , FeS ₂ , NbS ₂ , ZrS ₂ , VSe ₂ , and MnO ₂ , or transition metal chalcogen compounds, and many examples using inorganic materials as active materials have been studied. Furthermore, a composite electrode of a conductive polymer and an inorganic active material has also been proposed (Japanese Patent Laid-Open No. 63-10216).
2). In addition, when lithium metal is used as an electrode as the negative electrode active material, there are advantages that a high electromotive force is obtained, light weight and high density are easily achieved. However, lithium metal has a drawback that it produces dendrites by charge and discharge, and this dendrite decomposes the electrolytic solution, so that the cycle life of the battery is short. Further, when the dendrite grows further, it reaches the positive electrode and causes a short circuit in the battery. Using a lithium alloy as the negative electrode alleviates the above problems,
Satisfactory capacity as a secondary battery cannot be obtained. Therefore, it has been proposed to use a carbon material capable of inserting and extracting lithium as the negative electrode active material. For example, JP-A-61-2
No. 77515 discloses that a conductive carbon material obtained by heat-treating an aromatic polyimide at a temperature of 2000 ° C. or more in an inert atmosphere is used as a negative electrode active material. The use of graphitized spheroidal carbon as a negative electrode active material is disclosed. Further, Japanese Patent Application Laid-Open No. 61-77275 discloses a secondary battery in which an insulating or semiconductive carbon material having a polyacene structure obtained by heat-treating a phenolic polymer is used for an electrode. The positive electrode and the negative electrode using the carbon material are generally applied and molded using a binder. However, the coating type electrode has a problem in that it has a difficulty in adhering to a current collector regardless of whether it is a positive electrode or a negative electrode, and cracks or peeling may occur during battery production or during use. Further, there is a problem of the combination of the electrode and the electrolyte, which is seen in the decomposition of the solvent on the surface of the electrode, particularly the negative electrode. The deterioration of cycle characteristics due to these problems has not been solved yet.

[0003]

[Object] Therefore, an object of the present invention is to provide a non-aqueous electrolyte secondary battery that maintains the cycle characteristics while maintaining a high capacity.

[0004]

As a result of studies conducted to achieve the above object, when 50 to 500 ppm (weight based on the weight of the electrode) of N-methylpyrrolidone (NMP) is contained in the positive electrode and / or the negative electrode, the positive electrode The inventors have found that a non-aqueous electrolyte secondary battery having improved adhesion properties of a negative electrode and / or a current collector and having excellent cycle characteristics can be obtained, and thus reached the present invention. The NMP is most commonly used as a coating solvent for a battery electrode, is a solvent that dissolves a binder and further favorably disperses a positive electrode and a negative electrode active material. This NMP has an appropriate amount in the electrode (50 to 500 pp
m) When present, it acts on the interface between the active material and the binder to increase the strength of the electrode coating film, and at the interface between the active material and the electrolytic solution, increases the permeability of the electrolytic solution and hinders the decomposition of the solvent. It is considered that a battery having a high capacity and excellent cycle characteristics can be obtained by such an effect that is considered to be due to increasing the wettability of both at each interface. N contained in the electrode
If the amount of MP is less than 50ppm, the effect will be weak and 500
On the other hand, if it is more than ppm, the strength of the electrode coating film may be weakened, or a large amount of NMP may be mixed in the electrolytic solution, resulting in a decrease in capacity. The inclusion of the above-mentioned predetermined amount of NMP in the electrode can be achieved by examining the conditions such as the drying method and the drying time by using NMP alone or in a mixture with other solvent at the time of coating. . These drying conditions differ depending on the positive electrode, the negative electrode, or the material used, and are not particularly limited. The amount of NMP in the electrode can be measured by a gas chromatograph or the like, and in particular, in a pyrolysis gas chromatograph, the electrode sample can be analyzed as it is, which is very convenient. Further, NMP may be contained in either the positive electrode or the negative electrode, but is preferably contained in both the positive electrode and the negative electrode. The content of the binder in the positive electrode is 3% or less (weight with respect to the electrode weight), and the content of the binder in the negative electrode is 8% or less (weight with respect to the electrode weight). Examples of the binder include those commonly used as a binder for the positive electrode and the negative electrode. Among them, polyvinylidene fluoride has a good affinity with NMP and has a content of the binder as described above. Even if it exists, it exhibits a sufficient binding function and does not deteriorate cycle characteristics, so that higher capacity can be achieved.

The positive electrode active material used in the battery of the present invention is TiS ₂ , MoS ₂ , Co ₂ S ₅ , V ₂ O ₅ , MnO ₂ ,
Transition metal oxides such as CoO ₂ , transition metal chalcogen compounds and composites thereof with Li (Li composite oxide; Li
(MnO ₂ , LiMn ₂ O ₄ , LiCoO _2, LiNiO ₂ etc.)
In the present invention, LiMnO ₂ , L
iMn ₂ O ₄ , LiCoO _2, LiNiO _{2 and the} like are effective. Since it is difficult to mold these inorganic active materials as they are, they are generally dispersed and applied together with a binder. In addition to the inorganic active material, a one-dimensional graphitized product which is a thermal polymer of an organic substance, carbon fluoride, graphite, or a conductive polymer having an electric conductivity of 10 ^-2 S / cm or more, specifically polyaniline, Examples thereof include polymers such as polypyrrole, polyazulene, polyphenylene, polyacetylene, polyacene, polyphthalocyanine, poly-3-methylthiophene, polypyridine, and polydiphenylbenzidine, and derivatives thereof. These are advantageous in terms of moldability and processability as compared with the inorganic active material, but have a low volume energy density due to the low density of the active material, and have an electrolyte sufficient in the electrolytic solution for the electrode reaction. It is necessary, and since the concentration of the electrolyte solution changes greatly with the charge / discharge reaction, there is a problem that the change of the liquid resistance and the like is large, and an excessive amount of the electrolyte solution is required to perform a smooth charge / discharge reaction. . This is disadvantageous in improving the energy density. In order to solve such a problem, it is possible to use an organic and inorganic composite active material. These polymer materials have a high electric conductivity to have a current collecting ability, a binding ability as a polymer, and also function as an active material. The inorganic active material used for the composite positive electrode is preferably one having excellent potential flatness, and specifically,
Examples thereof include oxides of transition metals such as V, Co, Mn, and Ni, or composite oxides of the above transition metals and alkali metals, preferably lithium metals, and stable electrode potential, voltage flatness, and energy in an electrolyte solution. Taking density into consideration, crystalline vanadium oxide is preferable, and vanadium pentoxide is particularly preferable. The reason is that the potential flat portion of the discharge curve of crystalline vanadium pentoxide is relatively close to the electrode potential associated with the insertion and desorption of the anion of the conductive polymer. Examples of the conductive polymer include redox active materials such as polyacetylene, polypyrrole, polythiophene, polyaniline, and polydiphenylbenzidine. Particularly, a nitrogen-containing compound is particularly effective. These conductive polymer materials are required to have high ionic conductivity in terms of not only conductivity but also diffusion of ions. Among these, the electric capacity per weight is relatively large, and in a general-purpose non-aqueous electrolyte,
Polypyrrole, polyaniline or their copolymers are preferred because they can be charged and discharged relatively stably. More preferred is polyaniline.

A carbonaceous material is used as the negative electrode material used in the battery of the present invention. Examples of the carbonaceous negative electrode active material include graphite, pitch coke, synthetic polymer, and a sintered body of natural polymer. In the present invention, synthetic polymer such as phenol and polyimide, or natural polymer is used.
Conductivity obtained by firing an insulating or semiconducting carbon body, coal, pitch, synthetic polymer or natural polymer obtained by firing in a reducing atmosphere at 800 to 1300 ° C. in a reducing atmosphere at 800 to 1300 ° C. Carbon body,
2000 for coke, pitch, synthetic polymer, natural polymer
What is obtained by firing in a reducing atmosphere at a temperature of ℃ or more, and a graphite-based carbon body such as natural graphite is used, but a carbon body is preferable. Among them, mesophase pitch and coke are fired in a reducing atmosphere of 2,500 ° C or more. The resulting carbon body and natural graphite have excellent potential flatness and have favorable electrode characteristics. In a further preferred embodiment of the present invention, coke is 2500 ° C.
This is to use the composite negative electrode of the carbon body and natural graphite which is fired in the above reducing atmosphere. Although natural graphite has preferable characteristics in terms of potential flatness and current characteristics, it has a problem of decomposing propylene carbonate, which is a solvent of a general-purpose electrolytic solution that has been conventionally used in non-aqueous electrolytic solution secondary batteries. Further, the carbon body obtained by firing the coke in a reducing atmosphere at 2500 ° C. or higher does not have the above-mentioned problems and is characterized in that the electrolytic solution can be easily selected. On the other hand, by using a composite of a carbon body obtained by firing coke in a reducing atmosphere at 2500 ° C. or higher and natural graphite as a negative electrode, the potential flatness and current characteristics of natural graphite are retained, and A negative electrode that does not decompose the liquid can be produced. The carbon body is formed into a sheet by a wet papermaking method using the carbon body and the binder, or by a coating method using a coating material in which an appropriate binder is mixed with a carbon material. The electrode can be manufactured by supporting the electrode on a current collector as required by a method such as application, adhesion, and pressure bonding.

Examples of the positive and negative electrode current collectors used in the present invention include metal sheets such as stainless steel, gold, platinum, nickel, aluminum, molybdenum and titanium, metal foils, metal nets, punching metals, and extract bands. metal,
Alternatively, a net or non-woven fabric made of metal-plated fiber, metal vapor-deposited wire, metal-containing synthetic fiber or the like can be used. Of these, aluminum and stainless steel are preferably used in consideration of electrical conductivity, chemical, electrochemical stability, economic efficiency, workability and the like. More preferably, aluminum is preferable from the viewpoints of its lightness and electrochemical stability. Furthermore, the surfaces of the positive electrode current collector layer and the negative electrode current collector layer used in the present invention are preferably roughened. By roughening, the contact area of the active material layer is increased, and the adhesion is also improved, which has the effect of lowering the impedance of the battery. Further, in the production of an electrode using a coating solution, it is possible to greatly improve the adhesion between the active material and the current collector by subjecting it to a surface roughening treatment. Examples of the surface roughening treatment include polishing with an emery paper, blasting, and chemical or electrochemical etching, whereby the current collector can be roughened. In particular, in the case of stainless steel, blast processing is preferable, and in the case of aluminum, etched aluminum is preferable. Since aluminum is a soft metal, an effective surface roughening cannot be performed by blasting, and aluminum itself is deformed.
On the other hand, the etching treatment can effectively roughen the surface in the order of micrometer without deforming the aluminum or greatly reducing the strength thereof, and is the most preferable method for roughening the aluminum.

Finally, the electrolyte used in the present invention.
However, first, as the electrolyte salt, LiClO_Four, LiAs
F₆, LiPF₆, LiBF_Four, LiBr, LiCF_ThreeSO
_Three, LiN (CF_ThreeSO_Two)_Two, LiC (CF_ThreeSO_Two)_ThreeWhat
There is no particular limitation. Also,
You may mix and use these electrolyte salts. Electrolyte concentration and
Depending on the electrode used and the electrolytic solution, 0.
1 to 10 mol / l is preferable. And make up the electrolyte
Examples of the solvent to be used include tetrahydrofuran and 2
-Methyltetrahydrofuran, 1,4-dioxane, di
Ethers such as methoxyethane, dimethylformami
, Amides such as dimethylacetamide, acetonite
Nitriles such as ril and benzonitrile, dimethyl sulphate
Sulfur compounds such as hoxysulfolane, dimethyl carbonate
Sheet, diethyl carbonate, methyl ethyl carbonate
Chain methyl carbonate such as
Stell, ethylene carbonate, propylene carbonate
And cyclic carbonic acid esters such as butylene carbonate
However, the present invention is not limited to these.
Also, these may be used alone or in combination of two or more.
Is also good. Furthermore, as the electrolyte, a solid electrolyte is preferred.
Yes. For example, in an inorganic system, AgCl, AgBr, Ag
Metal halides such as I and LiI, RbAg_FourI_Five, Rb
Ag _FourI_FourExamples include CN, but polyethylene oxai
, Polypropylene oxide, polyvinylidene fluoride
And polyacrylamide as the polymer matrix,
A composite in which the above electrolyte salt is dissolved in a polymer matrix
Body or these gel crosslinks containing further solvent
Body, low molecular weight polyethylene oxide, crown ether
Of high-performance polymers by grafting ionic dissociative groups such as
Molecular solid electrolyte or high molecular weight polymer with the above electrolytic solution
An example of the gel-like polymer solid electrolyte is: This
Of these, gel polymer solid electrolytes are particularly preferable. Book
It is also possible to use a separator in the battery of the invention.
Wear. As a separator, ion migration of electrolyte solution
With low resistance and excellent solution retention
Good to use. As an example of such a separator
Is glass fiber, filter, polyester, tefro
Made of polymer fibers such as polyurethane, polyflon, polypropylene, etc.
Nonwoven filters, glass fibers and their polymeric fibers
A non-woven fabric filter etc.
You. The form of the battery using the electrode of the present invention is particularly limited
Not coin type, coin type, sheet type, cylinder type, gum type
It can be mounted on various batteries such as.

Examples of the present invention will be shown below.

Example 1 Polyvinylidene fluoride (PVDF) (3 parts by weight) was dissolved in N-methylpyrrolidone (NMP) (57 parts by weight), and natural graphite (40 parts by weight) was added. Was mixed and dispersed in to prepare a negative electrode coating material. This is applied on a 20 μm copper foil in the air using a wire bar and dried at 125 ° C. for 30 minutes to give a film thickness of 60 μm.
Was prepared. The amount of NMP contained in this electrode was measured using a pyrolysis gas chromatograph, and the results are shown in Table 1. The electrode prepared as described above was used as a negative electrode, the counter electrode was a Li plate, and the electrolyte solution was LiN (CF ₃ SO ₂ )
₂ ethylene carbonate / dimethyl carbonate (3
/ 7, volume ratio) 2.0 mol / l of the solution was used for the charge / discharge test. The charge and discharge test was made by Hokuto Denko HJ-201B
Using a charge and discharge measuring device, a constant current of 1.5 mA was applied to the battery for a constant current of 3 V until it reached 0 V, and after a 1-hour rest, the battery voltage was 0.8 V at a current of 1.5 mA. After discharging, this charging / discharging was repeated. The discharge capacity densities at the initial and 50th cycles in this case are shown in Table 1.

Example 2 The same as Example 1 except that the drying condition after coating was 100 ° C. for 20 minutes.

Example 3 The same as Example 1 except that the drying condition after coating was 80 ° C. for 15 minutes.

Example 4 2 parts by weight of polyvinylidene fluoride (PVDF) was dissolved in 58 parts by weight of N-methylpyrrolidone (NMP), 40 parts by weight of coke calcined at 2500 ° C. was added, and the mixture was subjected to a roll mill method. A negative electrode coating material was prepared by mixing and dispersing in an inert atmosphere. This was applied on a 20 μm copper foil in the air using a wire bar and dried at 100 ° C. for 15 minutes to produce an electrode having a film thickness of 60 μm. This electrode is used as a negative electrode, the counter electrode is a Li plate, and the electrolyte solution is LiCF ₃ S.
A charge / discharge test was conducted in the same manner as in Example 1 using 2.0 mol / l of an ethylene carbonate / diethyl carbonate (5/5, volume ratio) solution of O ₃ , and the results are shown in Table 1.

Example 5 2 parts by weight of a polyvinyl pyridine-acrylate copolymer and 0.01 part by weight of hexamethylene diisocyanate were dissolved in 58 parts by weight of N-methylpyrrolidone to obtain 40 parts by weight of a polyimide baked at 1000 ° C. In addition, a negative electrode coating material was prepared by mixing and dispersing in a roll mill method under an inert atmosphere. This was applied on a 20 μm copper foil in the air using a wire bar and dried at 130 ° C. for 15 minutes to prepare an electrode having a film thickness of 60 μm. The electrode prepared as described above was used as a negative electrode, the counter electrode was a Li plate, and the electrolyte solution was 2.0 mol / l of a propylene carbonate / dimethoxyethane (5/5, volume ratio) solution of LiBF ₄ , A charge / discharge test was conducted in the same manner as in No. 1, and the results are shown in Table 1.

Example 6 3 parts by weight of polyvinylidene fluoride (PVDF) was dissolved in 57 parts by weight of N-methylpyrrolidone (NMP), and 20 parts by weight of natural graphite and 20 parts by weight of coke burned at 2500 ° C. were added. Then, by a roll mill method, they were mixed and dispersed under an inert atmosphere to prepare a negative electrode coating material. This is applied to a 20 μm copper foil in the air using a wire bar,
It was dried at 80 ° C. for 15 minutes to prepare an electrode having a film thickness of 60 μm. The electrode manufactured as described above is used as the negative electrode, and the counter electrode is L
As an i-plate, the electrolyte solution was a LiN (CF ₃ SO ₂ ) ₂ ethylene carbonate / propylene carbonate / dimethyl carbonate (5/2/3, volume ratio) solution 2.0mo.
A charge / discharge test was conducted in the same manner as in Example 1 using 1 / l.
The results are shown in Table 1.

Example 7 3 parts by weight of polyvinylidene fluoride (PVDF) was dissolved in 38 parts by weight of N-methylpyrrolidone (NMP) to obtain 50 parts by weight of LiCoO ₂ as an active material and 9 parts by weight of graphite as a conductive agent. In addition, a homogenizer was used to mix and disperse under an inert atmosphere to prepare a positive electrode coating material. This was applied on a 20 μm SUS foil using a wire bar in the air and dried at 125 ° C. for 30 minutes to produce an electrode having a film thickness of 60 μm. The electrode manufactured as described above was used as a positive electrode, the counter electrode was a Li plate, and the electrolyte solution contained ethylene carbonate / diethyl carbonate (5/5, LiPF ₆ ).
A charge / discharge test was performed using 2.0 mol / l of the solution (volume ratio), and the results are shown in Table 1. The charge / discharge test was carried out using a HJ-201B charge / discharge measuring device manufactured by Hokuto Denko at a current of 0.4 mA, until the battery voltage reached 3.7 V, and after a pause of 1 hour at a current of 0.4 mA, The battery voltage was discharged to 2.5 V, and this charging / discharging was repeated thereafter. The discharge capacity densities at the initial and 50th cycles in this case are shown in Table 1.

Example 8 The same as Example 7 except that V ₂ O ₅ was used as the positive electrode active material.

Example 9 10 parts by weight of polyaniline synthesized by chemical polymerization using sulfuric acid and ammonium persulfate as an oxidizing agent were dissolved in 50 parts by weight of N-methylpyrrolidone to obtain 50 parts by weight of V ₂ O _{5 and} 6 parts by weight of graphite. Parts were added and mixed and dispersed using an homogenizer in an inert atmosphere to prepare a positive electrode coating material. This is used in the atmosphere with a wire bar for 20
It was applied onto a μm aluminum electrolytic foil and dried at 100 ° C. for 15 minutes to prepare an electrode having a film thickness of 60 μm. The electrode prepared as described above was used as a positive electrode, the counter electrode was a Li plate, and the electrolyte solution was a solution of LiN (CF ₃ SO ₂ ) ₂ in ethylene carbonate / propylene carbonate / dimethyl carbonate (5/2/3, volume ratio). A charge / discharge test was conducted in the same manner as in Example 7 using 2.0 mol / l, and the results are shown in Table 1.
It was shown to.

Example 10 20 parts by weight of LiPF _{6 and} 70 parts by weight of ethylene carbonate / diethyl carbonate (5/5, volume ratio) were mixed to prepare an electrolytic solution. To this, 12.8 parts by weight of polyoxyethylene acrylate, 0.2 parts by weight of trimethylolpropane acrylate, and 0.02 parts by weight of benzoin isopropyl ether were added and mixed and dissolved to prepare a photopolymerizable solution. The above-mentioned photopolymerizable solution was permeated into the negative electrode prepared in Example 2 and the positive electrode prepared in Example 9 and irradiated with a high pressure mercury lamp to solidify the electrolytic solution. These were laminated and heat-sealed on three sides while uniformly applying pressure to the power generation element part, and then the remaining one side was sealed under reduced pressure to produce a battery. The battery characteristics were evaluated in the same manner as in Example 1, and the results are shown in Table 2.

Comparative Example 1 The same as Example 1 except that the drying condition after coating was 120 ° C. for 40 minutes.

Comparative Example 2 The same as Example 1 except that the drying condition after coating was 80 ° C. for 10 minutes.

Comparative Example 3 The same as Example 6 except that the drying condition after coating was 125 ° C. for 40 minutes.

Comparative Example 4 The same as Example 6 except that the drying condition after coating was 80 ° C. for 10 minutes.

Comparative Example 5 The same as Example 7 except that the drying condition after coating was 120 ° C. for 50 minutes.

Comparative Example 6 The same as Example 9 except that the drying condition after coating was 120 ° C. for 50 minutes.

Comparative Example 7 The same as Example 9 except that the drying condition after coating was 80 ° C. for 15 minutes.

Comparative Example 8 The same as Example 10 except that the negative electrode of Comparative Example 1 and the positive electrode of Comparative Example 6 were used.

The results of the battery characteristic tests of the above Examples and Comparative Examples are shown in Tables 1 and 2 below.

[Table 1]

[0029]

[Table 2]

[0030]

【effect】

Claim 1 A secondary battery having a high capacity and extremely excellent cycle characteristics was obtained. Claim 2 In particular, the capacity is increased. Claim 3 has led to an improvement in cycle characteristics. Claim 4 In particular, the cycle characteristics are improved. Claim 5 In particular, the cycle characteristics are improved. Claim 6 has led to a particularly high capacity. Claim 7 has led to a particularly high capacity. Claim 8 In particular, the cycle characteristics are improved. Claim 9 has led to an improvement in cycle characteristics. Claim 10 In particular, the cycle characteristics are improved.

Claims (10)

[Claims] 1. A non-aqueous electrolyte secondary battery comprising at least a positive electrode, an electrolyte layer containing a non-aqueous electrolytic solution, and a carbon-based negative electrode capable of inserting and extracting lithium. In a positive electrode and / or a negative electrode, N-methylpyrrolidone ( Hereinafter, also referred to as NMP) 50 to 500 ppm (weight relative to electrode weight)
A non-aqueous electrolyte secondary battery characterized by containing. 2. The non-aqueous electrolyte according to claim 1, wherein the positive electrode has a binder content of 3% or less (weight with respect to the electrode weight) and the negative electrode binder content is 8% or less (weight with respect to the electrode weight). Secondary battery. 3. The binder of the positive electrode and / or the negative electrode is polyvinylidene fluoride (PVDF).
The non-aqueous electrolyte secondary battery according to the above. 4. The positive electrode active material is a composite oxide of lithium (A) and at least one kind (B) selected from the group consisting of cobalt, nickel and manganese.
Alternatively, the non-aqueous electrolyte secondary battery described in 3. 5. The non-aqueous electrolyte secondary battery according to claim 1, 2 or 3, wherein the positive electrode active material is a composite active material of an inorganic active material and a conductive polymer active material. 6. The non-aqueous electrolyte secondary battery according to claim 1, wherein the negative electrode active material contains two or more kinds of carbon materials. 7. The non-aqueous electrolyte secondary battery according to claim 6, wherein the two or more kinds of carbon materials are a composite active material of natural graphite and artificial graphite obtained by firing coke. 8. The non-aqueous electrolyte secondary battery according to claim 1, wherein the electrolyte layer is a polymer solid electrolyte. 9. The non-aqueous electrolyte secondary battery according to claim 8, wherein the polymer solid electrolyte is a gel polymer solid electrolyte. 10. The non-aqueous electrolyte secondary battery according to claim 1, wherein the electrolyte contains a cyclic carbonic acid ester.