JP2001297792A - Nonaqueous electrolyte cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonaqueous electrolyte cell having improved charging and discharging cycle life characteristics by restraining the growth of lithium dendrite caused by repeated charging and discharging. SOLUTION: The nonaqueous electrolyte cell is provided with an electrolyte and a polymer electrolyte containing a complex of ammonium salt containing hydrogen fluoride with the concentration of more than 1×10-4 mol/L and less than 1×10-1 mol/L.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a non-aqueous electrolyte battery provided with a lithium metal anode.

[0002]

2. Description of the Related Art In recent years, with the development of electronic devices, the appearance of new high-performance batteries is expected. Currently, the primary power sources for electronic devices are manganese dioxide / zinc batteries for primary batteries, and nickel-based batteries and lead batteries such as nickel-cadmium batteries, nickel-zinc batteries, nickel-hydride batteries for secondary batteries. Used in

As an electrolyte for these batteries, an alkaline aqueous solution such as potassium hydroxide or an aqueous solution such as sulfuric acid is used. The theoretical decomposition voltage of water is 1.23V. If the battery system has a value higher than the above value, water is likely to be decomposed, and it is difficult to stably store the energy as electric energy. Therefore, a battery having an electromotive force of only about 2 V has been practically used. Therefore, a non-aqueous electrolyte is used as an electrolyte for a high-voltage battery of 3 V or more. As a typical battery, there is a so-called lithium battery using lithium for the negative electrode.

The lithium primary battery includes a manganese dioxide lithium battery, a carbon fluoride lithium battery and the like, and the lithium secondary battery includes a manganese dioxide lithium battery and a vanadium oxide lithium battery.

[0005] Secondary batteries using lithium metal for the negative electrode are disadvantageous in that short-circuits are liable to occur due to dendritic deposition of lithium metal and the life is short. In addition, safety is high due to high reactivity of lithium metal. It is difficult to secure.

For this purpose, a so-called lithium ion battery using graphite or carbon instead of metallic lithium and using lithium cobaltate or lithium nickelate for the positive electrode has been devised and used as a high energy density battery. Recently, with the expansion of applications, batteries with higher performance, higher energy density and higher safety have been demanded.

In particular, when metallic lithium is used for the negative electrode, a high energy density battery is obtained. However, when the lithium is deposited, lithium is deposited in a dendrite shape and charging / discharging efficiency is lowered, so that sufficient cycle life performance cannot be obtained. It has become.

To solve this problem, by adding (C ₂ H ₅ ) ₄ NF (HF) ₄ HF complex as an additive to the electrolyte, it is possible to suppress the dendrite deposition on the lithium metal negative electrode and to fill the electrolyte. Attempts have been made to improve discharge efficiency (S. Shiraishi et al., Rec.
nt Res. Level in Pure & Ap
plied Chem. , 1 , p45 (1997),
K. Kanamuraet. al. , J. et al. Fluor
ine Chem. , 87 , p235 (1998), Hatanaka, Kanamura, Umegaki The 40th Battery Symposium Abstracts, p467
(1999)).

However, even in this case, sufficient cycle life performance has not been obtained. This is due to charging
The surface film formed by the reaction between the lithium metal, which is deposited in the form of particles instead of the dendrite, and the electrolyte, peels off without being able to follow the reduction in lithium particle size during discharge, and a new film is formed This is considered to be due to the consumption of metallic lithium.

When (C ₂ H ₅ ) ₄ NF (HF) ₄ is added to the electrolyte as an additive, metallic lithium precipitates in the form of particles at the beginning of the charge / discharge cycle, but the peeled coating film is formed. Deposition on the surface of the negative electrode hinders uniform diffusion of lithium ions, so that current concentration eventually occurs, and metallic lithium precipitates in a dendrite shape. As a result, the problem is that the dendritic metallic lithium causes an internal short circuit, and the cycle life is greatly reduced.

In a non-aqueous electrolyte battery, since a flammable organic solvent is generally used for an electrolyte, there is a possibility that erroneous use of the battery generates heat and smoke.
For this reason, it is necessary to use various safety elements, and there has been a problem that the energy density in consideration of the weight and volume of these elements is low and the cost is high.

In order to overcome this problem, many attempts have been made to apply a polymer electrolyte having lower reactivity with an electrode than an electrolyte. However, since the diffusion coefficient of lithium ions in the polymer electrolyte is small, there is a problem that the charge / discharge characteristics at a high rate are poor. To solve this problem,
It has been proposed that a polymer electrolyte be made porous and an electrolyte be contained in the pores, and some reports have been made (Summary of the 39th Battery Symposium, 1998, p.3).
37).

[0013]

In a non-aqueous electrolyte battery using lithium metal, when charge and discharge cycles are repeated, dendrites of lithium metal are generated during charging,
The problem is that not only fine metal lithium, which is difficult to discharge, accumulates in the vicinity of the negative electrode and the capacity is reduced, but also if the battery is short-circuited, the discharge capacity is significantly reduced.

Incidentally, even in a so-called lithium ion battery using a carbon material capable of occluding and releasing lithium ions such as graphite for the negative electrode, when overcharging, metallic lithium is deposited on the surface of the carbon material to generate dendrites. There is a problem similar to that of a battery using metallic lithium for the negative electrode.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a non-aqueous electrolyte battery having significantly improved charge / discharge cycle life.

[0016]

The non-aqueous electrolyte battery according to the present invention comprises a 1 × ammonium salt complex containing hydrogen fluoride.
It is characterized by comprising an electrolytic solution and a polymer electrolyte containing at a concentration of 10 ⁻⁴ mol / L or more and 1 × 10 ⁻¹ mol / L or less.

Further, the nonaqueous electrolyte battery according to the present invention is characterized in that a polymer electrolyte is attached in contact with a negative electrode.

Further, the nonaqueous electrolyte battery according to the present invention is characterized in that the polymer electrolyte is porous.

The non-aqueous electrolyte battery according to the present invention is characterized in that the polymer electrolyte contains carbon, silicon, tin or aluminum powder.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a thin and uniform lithium fluoride film is formed on the surface of a negative electrode by using an electrolytic solution containing a complex of an ammonium salt containing hydrogen fluoride. Concentration of charging current is suppressed, and metallic lithium can be deposited not in a dendrite shape but in a hemispherical shape. Therefore, the accumulation of fine metallic lithium that is difficult to discharge in the vicinity of the negative electrode is suppressed, the charge / discharge efficiency is improved, and the cycle life performance of the battery is improved.

Further, in the present invention, the metallic lithium anode can be pressed by applying the polymer electrolyte,
Peeling of the coating film at the time of discharge can be suppressed. Therefore, formation of a new film is less likely to occur, and the charge / discharge efficiency is improved, and excellent cycle life performance can be obtained.

In this case, the interface between the polymer electrolyte and the negative electrode follows the hemispherical deposition of metallic lithium by adjusting the degree of swelling in the electrolyte to make the hardness of the polymer electrolyte appropriate. Thus, the shape can be changed. Therefore, the entire individual particles of metallic lithium deposited in a hemispherical shape can be pressed by the polymer electrolyte,
An extremely excellent effect of suppressing film peeling can be obtained as compared with compression by a hard film whose shape such as a separator is hard to change.

In the non-aqueous electrolyte battery according to the present invention, (CH ₃ ) ₄ NF (HF) ₄ and (C ₂ H ₅ ) ₄ NF are used as complexes of ammonium salts containing hydrogen fluoride to be added to the electrolytic solution.
(HF) ₄ , (C ₃ H ₇ ) ₄ NF (HF) _{4 and the} like can be used. Further, the number of HFs to be coordinated does not need to be four, and may be any number from 1 to 4.

The present invention is mainly applicable to a non-aqueous electrolyte battery using lithium metal for the negative electrode. However, a so-called lithium ion using a carbon material such as graphite capable of occluding and releasing lithium ions for the negative electrode. The present invention also applies to lithium-ion batteries because batteries have the same problem that lithium metal precipitates on the surface of a carbon material and dendrites are generated when overcharged. it can.

That is, the anode material is not limited to the case where only metallic lithium is used.
Alloys of lithium with Si, Pb, Sn, Zn, Cd, etc.,
Tin oxide, used LiFe ₂ O _3, WO _2, MoO transition metal oxides such as _2, graphite, carbonaceous material such as low-crystalline carbon, Li ₅ (Li ₃ N) lithium nitride, or mixtures thereof such as it can. Also, these may be used in combination with metallic lithium. In addition, the shape of these negative electrode materials may be any of spherical, fibrous, massive, scale-like, and needle-like.

Further, by making the polymer electrolyte used in the present invention porous, the shape thereof is more easily changed following the deposition of hemispherical metallic lithium, so that the metallic lithium particles can be pressed more uniformly. It becomes possible. Since the polymer electrolyte has a higher viscosity than the organic electrolyte, the diffusion coefficient of lithium ions is small. Therefore, when a polymer electrolyte is used, the concentration polarization during charging increases, and it becomes difficult for metallic lithium to precipitate in the form of dendrites.

Further, when the polymer electrolyte is made porous, ions can be rapidly diffused through the electrolyte in the pores, so that the concentration polarization at the time of charging is reduced and the dendritic deposition of metallic lithium is suppressed. be able to.

For such reasons, it is preferable that the polymer electrolyte is porous. The porosity of the polymer electrolyte is desirably 10% to 90%, and the pore size is 0.0%.
It is preferably at least 03 μm and smaller than the particle size of metallic lithium.

As the polymer material of the polymer electrolyte used in the nonaqueous electrolyte battery according to the present invention, the following polymers may be used alone or in combination: polyethers such as polyethylene oxide and polypropylene oxide; Polyacrylonitrile, polyvinylidene fluoride, polyvinylidene chloride, polymethyl methacrylate,
Polymethyl acrylate, polyvinyl alcohol, polymethacrylonitrile, polyvinyl acetate, polyvinyl pyrrolidone, polyethylene imine, polybutadiene,
Polystyrene, polyisoprene, styrene butadiene rubber, nitrile rubber and derivatives thereof. Further, a polymer obtained by copolymerizing various monomers constituting the above polymer may be used.

Further, in the non-aqueous electrolyte battery according to the present invention, the following solvents can be used as the electrolyte:
Ethylene carbonate, propylene carbonate, dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, γ-butyrolactone, sulfolane, dimethyl sulfoxide, acetonitrile, dimethylformamide, dimethylacetamide, 1,2-dimethoxyethane, 1,2-diethoxyethane, tetrahydrofuran, Polar solvents such as 2-methyltetrahydrofuran, dioxolan, methyl acetate and the like, and mixtures thereof.

Further, the lithium salt contained in the lithium ion conductive polymer and in the non-aqueous electrolyte may be L
_{iPF 6, LiBF 4, LiAsF 6} , LiClO 4, Li
SCN, LiI, LiCl, LiBr, LiCF ₃ C
O ₂ , LiCF ₃ SO ₃ , LiN (SO ₂ CF ₃ ) ₂ , LiN
(SO ₂ CF ₂ CF ₃ ) ₂ , LiN (COCF ₃ ) ₂ and L
Lithium salts such as iN (COCF ₂ CF ₃ ) ₂ and mixtures thereof may be used. Further, different salts may be used in the ion conductive polymer and the non-aqueous electrolyte.

In the non-aqueous electrolyte battery according to the present invention, excellent charge / discharge cycle characteristics can be obtained by including a powder of carbon, silicon, tin or aluminum in the polymer electrolyte. Note that as the carbon, graphite, hard carbon, low-crystalline carbon, or the like can be used.

By including carbon, silicon, tin or aluminum powder in the polymer electrolyte, the carbon, silicon, tin or aluminum powder present in the polymer electrolyte and lithium which is difficult to discharge due to charge and discharge can be obtained. The particles and dendrites react to produce lithium intercalation material. As a result, not only the metallic lithium particles as a short-circuiting factor are reduced, but also when the electron conductive network is formed, it eventually contributes to the discharge again. Cycle characteristics can be obtained.

When the battery is assembled, the carbon, silicon, tin or aluminum powder present in the polymer electrolyte is not charged in preference to the deposition of metallic lithium on the negative electrode. Most of the carbon, silicon, tin or aluminum powder present therein must be separated from the negative electrode in electronic conduction.

When a porous polymer film or a lithium ion conductive polymer film is used as a polymer electrolyte containing carbon, silicon, tin or aluminum, the conventional discharge performance is not impaired.

Further, by making the polymer electrolyte porous and retaining the electrolyte in the pores, the particulate lithium or dendritic metallic lithium which has been released from the negative electrode and cannot be charged or discharged becomes active material during charging and discharging. Due to the flow of the electrolytic solution caused by the change in the volume of the electrolyte, the electrolyte moves in the pores of the polymer membrane and can reach the powder of carbon, silicon, tin or aluminum contained in the membrane.

Therefore, since the amount of metallic lithium released from the negative electrode, which is not absorbed by the powder of carbon, silicon, tin or aluminum, is reduced, it is possible to suppress a decrease in capacity due to a minute short circuit, and to improve the safety and charge / discharge cycle characteristics of the battery. Is significantly improved.

In order to improve the charge / discharge cycle characteristics, the porosity of the polymer film is desirably 10% to 90%, and the pore diameter is desirably 0.003 μm to 10 μm.

Further, as the compound capable of occluding and releasing lithium as the positive electrode material, as the inorganic compound, a composition formula Li _x MO ₂ or Li _y M ₂ O ₄ (where M is a transition metal, 0 ≦ x ≦ 1) , 0 ≦ y ≦ 2), a composite oxide, an oxide having tunnel-like vacancies, and a metal chalcogenide having a layered structure can be used. Specific examples thereof include LiCoO ₂ , LiNiO ₂ , LiMn ₂ O ₄ , L
i ₂ Mn ₂ O ₄ , MnO ₂ , FeO ₂ , V ₂ O ₅ , V ₆ O ₁₃ ,
TiO ₂ , TiS ₂ , NiOOH, FeOOH, FeS,
LiMnO _{2 and the} like. Examples of the organic compound include a conductive polymer such as polyaniline. Further, the above-mentioned various active materials may be mixed and used regardless of an inorganic compound or an organic compound.

In the non-aqueous electrolyte battery according to the present invention, the short-circuit preventing film is not limited to the polymer electrolyte and the porous polymer electrolyte, but may be a gel electrolyte in which the polymer electrolyte contains an electrolyte. When a porous polymer electrolyte is used as the polymer electrolyte, the electrolyte contained in the polymer may be different from the electrolyte contained in the pores of the polymer.

Further, as the short-circuit preventing film, a combination of an insulating microporous film and a polymer electrolyte may be used. In this case, it is preferable that the polymer electrolyte is applied in contact with the negative electrode in order to apply pressure to the negative electrode by applying the polymer electrolyte and to suppress peeling of the coating during discharge.

[0042]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of the present invention will be described.

Example 1 LiCoO ₂ 70 Wt%, acetylene black 6 Wt%, polyvinylidene fluoride (PVDF) 9 Wt%, n-methylpyrrolidone (NM)
P) A mixture of 15 Wt% is 20 mm wide and 20 mm thick.
It was applied on a μm aluminum foil and dried at 150 ° C. to evaporate NMP. After the above operation was performed on both surfaces of the aluminum foil, it was pressed to obtain a positive electrode. A nickel foil having a thickness of 10 μm and a width of 21 mm was used as a negative electrode.

A mixture of NMP and polyacrylonitrile (PAN) having a molecular weight of about 100,000 at a weight ratio of 10: 1 was stirred for 10 hours to dissolve PAN in NMP. After applying the paste thus produced in a uniform thickness on a glass plate, the paste was dried by heating at 85 ° C. for 2 hours.
The PAN was solidified by removing NMP to form a film. The thickness of the PAN film was 25 μm, and the porosity was calculated to be 0%.

Using the positive electrode, negative electrode and PAN film manufactured as described above, a positive electrode, a PAN film, a negative electrode,
Layered and wound in the order of the membrane, height 47.0 mm, width 22.2 m
m, and inserted into a square aluminum case having a thickness of 7.0 mm. Ethylene carbonate (EC) and dimethoxyethane (DME) were mixed at a volume ratio of 1: 1 and 1 mol / mol
l of LiClO ₄ were added, and the HF complex (C ₂ H
₅ ) A battery according to the present invention was manufactured by injecting an electrolytic solution to which ₄ NF (HF) ₄ was added. The capacity of the completed battery is about 9
00 mAh.

In the battery, the PAN was swollen by the electrolyte to form a polymer electrolyte membrane exhibiting lithium ion conductivity. In this battery, metallic lithium does not exist on the negative electrode at the time of battery assembly, but metallic lithium is deposited on the negative electrode by charging. A groove is formed in the aluminum case (a so-called non-return type safety valve). When the internal pressure of the battery increases, a crack is generated in the groove to release gas inside the battery, so that the battery case does not rupture. I made it.

It should be noted that (C ₂ H ₅ ) ₄ NF (H
F) The added amount of ₄ is 1 × 10 ⁻⁴ mol / L and 1 ×, respectively.
10 ⁻³ mol / L, 1 × 10 ⁻² mol / L, 1 × 10 ⁻¹
Four types of batteries having a mol / L ratio were manufactured, and the batteries (A), (B), (C), and (D) according to the present invention were sequentially formed.

Also, batteries (A), (B), (C) and (D) according to the present invention were used in the same manner except that a standard polyethylene separator having a porosity of 40% was used instead of the PAN membrane. Thus, conventionally known comparative batteries (E), (F), (G) and (H) were produced. In these comparative batteries, the polyethylene separator does not become a polymer electrolyte because the polyethylene separator does not swell with the electrolytic solution and the portions other than the pores do not exhibit ionic conductivity.

Further, (C ₂ H ₅ ) ₄ NF (HF) ₄
Except that no battery is added, the battery (A) according to the invention,
A conventionally known comparative battery (I) was manufactured in the same manner as (B), (C) and (D).

The batteries (A), (B), (C) and (D) according to the present invention and the comparative batteries (E), (F), (G), (H) and (I) ) Using 5
A zero cycle life test was performed. In the life test, one cycle consisted of constant-voltage charging at 4.2 V for 2 hours after constant-current charging until the voltage reached 4.2 V at 45 mA and constant-current discharging to 3.0 V at 45 mA.

FIG. 1 shows the cycle life test results of these batteries. From FIG. 1, the battery (A) according to the present invention,
(B), (C) and (D) were all found to have improved cycle life performance compared to comparative batteries (E), (F), (G), (H) and (I).

This corresponds to the battery (A) according to the present invention,
In (B), (C) and (D), the use of an electrolyte containing a complex of an ammonium salt containing hydrogen fluoride suppresses the precipitation of dendritic lithium on the surface of the metal lithium anode, and at the same time, the polymer By using the electrolyte, the metallic lithium negative electrode can be pressed, and the peeling of the coating film during discharge can be more effectively suppressed.

That is, by using the electrolytic solution containing the complex of the ammonium salt containing hydrogen fluoride, a thin and uniform lithium fluoride film is formed on the surface of the lithium metal negative electrode, and the concentration of the charging current is suppressed. As a result, metallic lithium can be deposited in a hemispherical shape instead of a dendrite shape, and the accumulation of fine metallic lithium, which is difficult to discharge near the negative electrode, is suppressed, and the charge / discharge efficiency is improved.

In addition to this, it is considered that the application of the polymer electrolyte makes it possible to press the metallic lithium negative electrode, and it is possible to more effectively suppress the peeling of the film during the discharge. In this case, since the peeling of the coating is suppressed, it is difficult to form a new coating, the charge / discharge efficiency is improved, and excellent cycle life performance can be obtained.

In the battery according to the present invention, the hardness of the polymer electrolyte is moderate. In particular, when the polymer electrolyte is attached in contact with the negative electrode, the interface between the polymer electrolyte and the negative electrode has a hemispherical metallic lithium deposition. The main reason why the cycle life performance was improved was that the shape of the metal lithium was changed in accordance with the above and the entire individual particles of the metal lithium deposited in a hemispherical shape could be pressed by the polymer electrolyte.

The batteries (E), (F), (G) and (H) of the comparative examples use an electrolyte containing a complex of an ammonium salt containing hydrogen fluoride, but use a polymer electrolyte. For this reason, the cycle life performance was only slightly improved when compared with the battery I of the comparative example using the electrolyte solution containing no ammonium salt complex containing hydrogen fluoride.

It should be noted that (C ₂ H ₅ ) ₄ NF (H
F) The addition amount of ₄ is less than 1 × 10 ⁻⁴ mol / L, or 1
Even when the concentration exceeds × 10 ^-1 mol / L, batteries were manufactured in the same manner as the batteries according to the present invention, but the cycle life characteristics of these batteries were (C ₂ H ₅ ) ₄ NF (H
F) It was comparable to Battery I without the addition of ₄ , and did not have sufficient cycle life characteristics as the battery according to the present invention.

Example 2 A battery (J) according to the present invention was manufactured in the same manner as the battery (C) according to the present invention in Example 1, except that the PAN membrane used as the polymer electrolyte was made porous.

The porous PAN film was manufactured as follows. N
A mixture of MP and polyacrylonitrile (PAN) having a molecular weight of about 100,000 at a weight ratio of 10: 1
After stirring for an hour, the PAN was dissolved in the NMP. The paste produced in this manner was applied to a glass plate at a uniform thickness, then immersed in water to remove NMP, thereby solidifying the PAN to form a film. When the polymer solidifies,
Since the path through which NMP escapes in water is a hole, the resulting film is a porous film having communication holes.

This film was vacuum-dried at 65 ° C. for 10 hours to remove water, and then pressed to form a film having a thickness of 25 μm. The porosity after pressing is 50% and the average pore size is 0.1μ
m.

Using the battery (J) according to the present invention manufactured as described above and the battery (C) according to the present invention manufactured in Example 1, the same charge / discharge cycle life test as in Example 1 was performed. Was. The result is shown in FIG.

From FIG. 2, it was found that the battery (J) according to the present invention exhibited better charge / discharge cycle life performance than the battery (C) according to the present invention. This is because, by making the polymer electrolyte porous, the shape can be more easily changed following hemispherical lithium metal deposition,
This is considered to be because it becomes possible to press the metal lithium particles more uniformly.

Further, since the polymer electrolyte has a higher viscosity than the organic electrolyte, the diffusion coefficient of lithium ions is small. Therefore, when using a polymer electrolyte,
The concentration polarization at the time of charging increases, and metallic lithium tends to precipitate in the form of dendrite.

When the polymer electrolyte is made porous,
Since the ions can be quickly diffused through the electrolyte in the pores, the concentration polarization during charging is reduced, and the dendritic precipitation of lithium metal can be suppressed. This is considered to be one of the reasons why the battery shows superior charge-discharge cycle life performance than the battery (C).

In the battery (J) according to the present invention, the PAN film as the polymer electrolyte had a porosity of 50%.
Even when the porosity of the PAN film was changed in the range of 10% to 90%, the same result as the battery (J) according to the present invention was obtained.

In the battery (J) according to the present invention, the pore diameter of the PAN membrane, which is a polymer electrolyte, is 0.1 μm.
However, even when the pore diameter of the PAN film was changed in the range of 0.01 μm to 3 μm, the same result as the battery (J) according to the present invention was obtained.

In the battery (J) according to the present invention, the amount of (C ₂ H ₅ ) ₄ NF (HF) ₄ added to the electrolyte was 1
× 10 ^-2 mol / L, but (C ₂ H ₅ ) ₄ NF (H
The amount of F) ₄ from ^{1 × 10 -4 mol / L 1} × 10 -1
The same result as in the battery (J) according to the present invention was obtained when the concentration was changed in the range up to mol / L.

Example 3 A battery (K) according to the present invention was manufactured in the same manner as the battery (J) according to the present invention in Example 2 except that carbon powder was included in the PAN film.

A PAN film containing carbon powder was manufactured as follows. A mixture of NMP, polyacrylonitrile (PAN) having a molecular weight of about 100,000, and spherical graphite powder having a particle size of 2 μm in a weight ratio of 50: 5: 1 was stirred for 10 hours to dissolve PAN in NMP. The paste prepared as described above was applied to a glass plate at a uniform thickness, then immersed in water to remove NMP, thereby solidifying the PAN, thereby producing a PAN film containing graphite particles. When the polymer solidifies, the path through which NMP escapes in water is a hole, and the resulting film is a porous film having communication holes.

This film was vacuum-dried at 65 ° C. for 10 hours to remove water, and then pressed to form a film having a thickness of 25 μm. The porosity after pressing is 50% and the average pore size is 0.1μ
m. Note that the porosity of the polymer membrane described in the present specification means a ratio of the pore volume obtained by subtracting the volumes of solids such as polymer and carbon from the apparent volume of the membrane containing pores to the apparent volume. I do.

Using the battery (K) according to the present invention manufactured as described above and the battery (J) according to the present invention manufactured in Example 2, 1 was obtained under the same charge / discharge conditions as in Example 1.
A life test of 50 cycles was performed. The result is shown in FIG.
It was shown to.

From FIG. 3, it was found that the battery (K) according to the present invention exhibited better charge / discharge cycle life performance than the battery (J) according to the present invention. This is because by providing a polymer film containing carbon between the positive electrode and the negative electrode, the intrinsic carbon reacts with lithium particles or dendrites, which are difficult to discharge due to charging and discharging, and form a lithium intercalation substance. This is considered to be due to the fact that metallic lithium particles as a short-circuit factor were reduced.

Further, when the electron conductive network of the negative electrode is formed up to the carbon powder due to the deposition of metallic lithium by charging, the decrease in capacity can be suppressed remarkably because the network eventually contributes again to discharging. It is considered that the obtained charge / discharge cycle characteristics were obtained.

Further, since the polymer film containing carbon is porous, by holding the electrolytic solution in the pores, lithium particles and dendritic metal lithium which have been released from the negative electrode and cannot be charged or discharged can be removed. It is considered that the flow of the electrolytic solution caused by the change in the volume of the active material at the time of charging / discharging moved the pores of the polymer membrane to reach the carbon contained in the membrane.

Therefore, it is not absorbed by carbon,
It is considered that since the amount of metallic lithium released from the negative electrode was reduced, the capacity reduction due to a minute short circuit could be suppressed, and the charge / discharge cycle characteristics of the battery were significantly improved.

In the battery (K) according to the present invention, the PAN film, which is a polymer electrolyte containing carbon, has a porosity of 50%.
However, even when the porosity was changed in the range of 10% to 90%, the same result as the battery (K) according to the present invention was obtained.

In the battery (K) according to the present invention, the pore diameter of the PAN film, which is a polymer electrolyte containing carbon, was 0.1 μm, but this pore diameter was 0.01 μm to 3 μm.
m, the same result as the battery (K) according to the present invention was obtained.

In the battery (K) according to the present invention, the amount of (C ₂ H ₅ ) ₄ NF (HF) ₄ added to the electrolyte was 1
× 10 ^-2 mol / L, but (C ₂ H ₅ ) ₄ NF (H
The amount of F) ₄ from ^{1 × 10 -4 mol / L 1} × 10 -1
The same result as that of the battery (K) according to the present invention was obtained when the concentration was changed in the range up to mol / L.

In the battery (K) according to the present invention, graphite is used as carbon to be contained in the polymer electrolyte. However, even when low-crystalline carbon is used instead of graphite, the battery (K) according to the present invention is used. The same result was obtained.

[0080]

In the nonaqueous electrolyte battery, hydrogen fluoride is used.
1 × 10 ^-Fourmol / L or more
1 × 10^-1mol / L or less
The energy density is increased by providing the rimer electrolyte
Non-aqueous electrolyte battery with high charge and discharge cycle life
Becomes possible.

[Brief description of the drawings]

FIG. 1 is a diagram showing cycle life test results of batteries of Examples A to D and Comparative Examples EI.

FIG. 2 is a diagram showing a cycle life test result of the batteries of Examples C and J.

FIG. 3 is a diagram showing a cycle life test result of the batteries of Examples J and K.

Claims (4)

[Claims] 1. An electrolyte comprising a complex of an ammonium salt containing hydrogen fluoride at a concentration of 1 × 10 ^-4 mol / L or more and 1 × 10 ^-1 mol / L or less, and a polymer electrolyte. Non-aqueous electrolyte battery. 2. The non-aqueous electrolyte battery according to claim 1, wherein the polymer electrolyte is attached in contact with the negative electrode. 3. The non-aqueous electrolyte battery according to claim 1, wherein the polymer electrolyte is porous. 4. The non-aqueous electrolyte battery according to claim 1, wherein the polymer electrolyte contains carbon, silicon, tin or aluminum powder.