JP2002216842A - Nonaqueous cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonaqueous cell applicable for either of a primary cell and a secondary cell, which has high capacity when use as a primary cell, and has high capacity and excellent cycle property when used as a secondary cell. SOLUTION: For the nonaqueous cell, comprising a positive electrode using poly carbon sulfide as a positive electrode activator expressed by the general formula; (CSx)n, (where, x is 0.5-1.5, and n is an integer of 4 or more), a negative electrode, and a nonaqueous electrolyte, a lithium salt of poly sulfide is contained in the electrolyte. As the lithium salt of poly sulfide, it is recommendable to use the lithium salt of poly sulfide expressed by the formula; Li2Sm, (where, m is an integer of not less than two).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a non-aqueous battery,
More specifically, the present invention relates to a non-aqueous battery that can be applied to a primary battery and a secondary battery.

[0002]

2. Description of the Related Art With the rapid expansion of portable electronic devices in the market, there is an increasing demand for higher performance of batteries used as power sources thereof, and on the other hand, development of more environmentally friendly batteries. Is required. Under such circumstances, sulfur (sulfur) is a low-cost, low-impact, and high-capacity cathode active material for non-aqueous batteries.
And its derivatives are expected to grow.

If this two-electron reaction of sulfur can be used in batteries, theoretically elemental sulfur would be 1675 mAh / g
Active material having a large energy density. However, since sulfur is an insulator with high insulating properties, in an alkali metal-sulfur battery utilizing a reduction reaction to alkali metal sulfide, it is necessary to co-exist with a conductive auxiliary having no reactivity with sulfur. However, in reality, only a low utilization rate can be obtained. In addition, sulfur is poor in reversibility, and sulfur and its derivatives at high temperatures have a high activity, so that there is a problem that the battery case and the like are eroded, and it is said that application to small consumer batteries is difficult. ing.

In addition, organic sulfur compounds such as polycarbon sulfide (CS _w ) _p (w is 2.3 to about 50, p is 2 or more) having a high energy density of 1000 to 1600 mAh / g are used in non-aqueous secondary batteries. Skotheim et al. Have announced that they have developed a sulfur-based non-aqueous secondary battery exhibiting high capacity even at room temperature (Japanese Patent Application Laid-Open No. 11-514128, US Pat. 441,831). This polycarbon sulfide can be prepared by reacting sodium sulfide with elemental sulfur and then reacting with an organic chloride compound, or by reacting acetylene with elemental sulfur in an ammonia solution of metallic sodium, or by disulfide using metallic sodium as a catalyst. It can be produced by a method of reacting carbon and dimethyl sulfone. The molecular structure of the polycarbon sulfide is characterized in that it has a conjugated structure having mainly carbon as a skeleton and polysulfide as a side chain.

[0005] In addition, a soluble sulfur compound which can be dissolved in an organic solvent is also used as a positive electrode active material of a battery (US Pat. No. 4,410,609, US Pat. No. 3,806).
369). In batteries using these dissolved sulfur compounds, a porous carbon electrode is used as the positive electrode, which can be discharged at a higher current than conventional sulfur batteries.However, the carbon constituting the electrode is discharged during the discharge process. Since it is easily deteriorated, it has been mainly used as a primary battery.

[0006]

SUMMARY OF THE INVENTION In order to obtain a high-capacity non-aqueous battery, the present inventors have repeatedly studied the same sulfur-based battery based on a concept different from that of the above-mentioned prior art, and have found that almost the same carbon-based non-aqueous battery is used. And a general formula (CS _x ) _n (x is 0. 1) consisting of only two elements, i.
5 to 1.5, and n is a number of 4 or more), and a secondary battery using the same as a positive electrode active material has a high capacity and can be charged and discharged. Confirmed that there was a patent application for it.
00-031305).

However, the batteries using the above-mentioned carbon polysulfide also have a problem to be improved in the cycle life at the time of large current charge / discharge.

[0008]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have found that the above-mentioned general formula (C)
S _x ) _n (x is 0.5 to 1.5, and n is a number of 4 or more) is converted to a lithium salt of polysulfide, which is a kind of dissolved sulfur compound. It has high catalytic activity and finds that the reversibility of the lithium salt of polysulfide is enhanced, and the combination of the above-mentioned carbon polysulfide and the lithium salt of polysulfide as the positive electrode active material provides a high capacity and large current charge / discharge cycle. A non-aqueous battery having excellent characteristics was constructed, and the present invention was completed.

That is, the present invention provides a compound represented by the general formula (CS _x ) _n
(X is 0.5 to 1.5, and n is a number of 4 or more) comprising a positive electrode containing carbon sulfide as a positive electrode active material, a negative electrode, and a non-aqueous electrolyte. A non-aqueous battery characterized in that the electrolyte contains a lithium salt of polysulfide.

In the nonaqueous battery of the present invention, since the lithium salt of polysulfide acting as a positive electrode active material is present in a state of being dissolved in the electrolytic solution, the positive electrode active material in the battery is mixed with the lithium salt of polysulfide and the positive electrode. Of the general formula (CS _x ) _n , and both of them can be charged and discharged with good reversibility. Therefore, the non-aqueous battery of the present invention is applicable as a high capacity primary battery. While being possible, it is also applicable as a secondary battery having high capacity and excellent cycle characteristics.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, as a lithium salt of polysulfide to be contained in an electrolytic solution, for example,
Those represented by the general formula Li ₂ S _m (where m is a number of 2 or more) are suitably used, and specific examples thereof include, for example,
Li ₂ S ₄ , Li ₂ S ₆ , Li ₂ S ₈ , Li ₂ S ₁₂ , L
i ₂ S _{18 and the} like. Then, the above general formula Li ₂
In _Sm , as m increases, the viscosity of the electrolytic solution increases and the ionic conductivity tends to decrease, or the solubility tends to decrease. Therefore, m is preferably 50 or less, and 20 or less is most preferably used practically. .

The electrolyte containing the lithium salt of polysulfide is prepared by dissolving an electrolyte salt such as a lithium salt in a non-aqueous solvent.

This non-aqueous solvent is usually composed of a main solvent and a co-solvent. The main solvent is required to have good solubility for the lithium salt of polysulfide. Specific examples of the main solvent include, for example, aromatic solvents such as toluene and benzene, tetrahydrofuran, dimethylformamide, 1,2-dimethoxyethane, tetramethylethylenediamine, dioxolan, 2-methyl-tetrahydrofuran, and tetraethyleneglycol dimethyl ether. (Tetraglyme) and the like, aliphatic or alicyclic low molecular weight solvents containing intramolecular oxygen or intramolecular nitrogen, solvents containing sulfur atoms such as dimethylsulfoxide and sulfolane, and the like. Can be used alone or as a mixed solvent of two or more. Among these solvents, particularly, solvents having a strong donor property (electron donating property) such as dimethyl sulfoxide, sulfolane, tetrahydrofuran, and tetraethylene glycol dimethyl ether are preferable. It is preferable to use in combination with a low viscosity ether represented by Then, the non-aqueous solvent can be constituted only by the main solvent.

As the co-solvent, for example, esters such as ethylene carbonate, propylene carbonate, butylene carbonate and γ-butyrolactone are used, and sulfur-based esters such as ethylene glycol sulfite can also be used. Further, in addition to these, chain esters such as dimethyl carbonate, diethyl carbonate, methyl ethyl carbonate, and methyl propionate, chain phosphoric acid triesters such as trimethyl phosphate, and diethyl ether can also be used.
Although the addition of these co-solvents increases the ionic conductivity of the system, it tends to cause a decrease in the solubility of the lithium salt of polysulfide.Therefore, the amount of the sub-solvent depends on the nature of the main solvent. It is preferably at most 20% by weight in the solvent.

When a compound having a C ＝ C unsaturated bond (including an aromatic compound) is added to the electrolytic solution as an additive, a negative electrode mixture layer is formed at a high density in order to increase the capacity. This is preferable because the deterioration of the cycle characteristics can be suppressed. As such a compound having a C ＝ C unsaturated bond, a fluorinated compound is particularly preferable, and a compound having an ester bond is more preferable. A preferable specific example thereof is, for example, H (CF ₂ ) ₄ CH ₂ OOC
CH = CH ₂ , F (CF ₂ ) ₈ CH ₂ CH ₂ OOCCH
= Fluorinated ester such as CH ₂ and the like.

In preparing the electrolytic solution, the
As an electrolyte salt to be used, for example, LiClO_Four, LiP
F₆, LiBF_Four, LiAsF₆, LiSbF₆, Li
CF _ThreeSO_Three, LiC_FourF₉SO_Three, LiCF_ThreeC
O_Two, Li_TwoC_TwoF_Four(SO_Three) _Two, LiN (RfSO
_Two) (Rf'SO_Two), LiN (RfOSO)_Two) (R
f'OSO_Two), LiC (RfSO_Two)_Three, LiC_pF
_{2p + 1}SO_Three(P ≧ 2), LiN (RfOSO_Two)_Two[This
Rf and Rf 'are each a fluoroalkyl group]
Alternatively, two or more kinds are used in combination. L among them
iCF_ThreeSO_Three, LiN (CF_ThreeSO_Two)_TwoEspecially
It is preferably used. The concentration of this electrolyte salt in the electrolyte
If too high, the polysal
The solubility of the lithium salt of fide is reduced,
0.5 to 1.5 mol / l is preferable because the amount decreases.
No.

The content of the lithium salt of polysulfide in the electrolytic solution depends on the nature of the solvent constituting the electrolytic solution, but the sulfur concentration is preferably 2 mol / l or more, more preferably 4 mol / l or more. Also,
It is preferably at most 20 mol / l, more preferably at most 16 mol / l. By setting the content of the lithium salt of polysulfide in the electrolytic solution to 4 mol / l or more as described above, a higher capacity can be more suitably realized, and 16 mol / l.
By setting it to 1 or less, the ionic conductivity of the system and the utilization rate of the active material can be suitably maintained.

After dissolving the lithium salt of polysulfide, the electrolyte is gelled with a gelling agent,
It may be used in the form of a gel. In gelation, for example, linear polymers such as polyethylene oxide and polyacrylonitrile or copolymers thereof, and polyfunctional monomers (eg, pentaerythritol tetraacrylate, Active hydrogens of tetrafunctional or higher acrylates such as methylolpropane tetraacrylate, ethoxylated pentaerythritol tetraacrylate, dipentaerythritol hydroxypentaacrylate, dipentaerythritol hexaacrylate and tetrafunctional or higher methacrylates similar to the above acrylates) and amine compounds For example, a monomer or the like that is polymerized by utilizing a reaction between the compound and urethane isocyanate groups is used.
However, in the case of a monomer, the monomer does not act as a gelling agent as it is, but a polymer obtained by polymerizing them acts as a gelling agent.

In the present invention, the composition of the carbon sulfide used for producing the positive electrode slightly varies depending on the synthesis conditions. However, when the composition is represented by the general formula (CS _x ) _n , x is 0.5 to 0.5. 1.5 and n is 4 or more. In the general formula (CS _x ) _n representing the carbon polysulfide, x is set to 0.5 to 1.5 because x is _equal to 0.1.
If it is smaller than 5, C--S--C bonds which do not participate in charge / discharge increase, and the capacity decreases. If x is larger than 1.5, the mixed amount of polysulfide increases, and the stability of the molecule is increased. And the reversibility at the time of charge and discharge is reduced. The reason why n is 4 or more is that, when n ≦ 3, it is difficult to synthesize carbon sulfide having a C—S—S—C bond, and even if synthesized, the capacity as an active material is low and the usefulness is low. Is considered to be low. In the general formula (CS _x ) _n representing the carbon polysulfide, x is preferably 0.8 to 1.3, and 0.9 to 1.x.
1 is more preferred. The larger the value of n, the better.

The carbon polysulfide represented by the above general formula (CS _x ) _n has only a broad diffraction peak near a diffraction angle 2θ = 25 ° when X-ray diffraction is performed using CuKα radiation. Are preferred. In addition, the above general formula (C
Polysulfide carbon represented by S _{x) n,} when subjected to Raman spectrometry, in its Raman spectrum, in the range of 400cm ^-1 ~525cm ^-1 Raman shift substantially single in the vicinity of 490 cm ^-1 Only peak, 144
It preferably has a peak with a large intensity around 4 cm ^-1 .

The carbon sulfide represented by the general formula (CS _x ) _n has a strong catalytic activity for the above-mentioned lithium salt of polysulfide and enhances its charge / discharge reversibility, although the reason is not clear. . Therefore, in the non-aqueous battery of the present invention, the positive electrode active material is composed of the carbon polysulfide represented by the general formula (CS _x ) _n and the lithium salt of polysulfide dissolved in the electrolytic solution, so that the battery has a high capacity. And excellent cycle characteristics can be obtained even when charging and discharging with a large current.

The positive electrode is formed, for example, by the general formula (CS _x ) _n
In the positive electrode active material composed of carbon polysulfide represented by, if necessary, for example, flaky graphite, acetylene black,
A conductor such as carbon black and a binder such as polyvinylidene fluoride and polytetrafluoroethylene are added and mixed to prepare a positive electrode mixture, which is then dispersed in a solvent to form a paste. The positive electrode mixture-containing paste may be mixed with a positive electrode active material, or the like, and the positive electrode mixture-containing paste may be applied to a positive electrode current collector made of a metal foil such as a nickel foil or an aluminum foil, dried, and dried at least in part of the positive electrode current collector. It is produced by forming a positive electrode mixture layer and, if necessary, subjecting it to pressure molding and thickness control. However, the method for producing the positive electrode is not limited to the method described above, but may be another method. In addition, as the conductor, in addition to the above examples, a conductive polymer or the like can be used.As the binder, in addition to the above examples, amorphous polyether, polyacrylamide, solubility in an organic solvent can be used. Polyaniline, polypyrrole, copolymers thereof, and the like can also be used.

The material used for the negative electrode may be any material capable of inserting and extracting lithium. In the present invention, the material is referred to as a negative electrode active material. Specific examples of such a negative electrode active material include, for example, And carbon materials such as graphite, pyrolytic carbons, cokes, glassy carbons, fired organic polymer compounds, mesocarbon microbeads, carbon fibers, and activated carbon. In addition, alloys such as Si, Sn, and In, and compounds such as oxides that can be charged and discharged at a low voltage near Li can also be used as the negative electrode active material.

When a carbon material is used as the negative electrode active material,
The carbon material preferably has the following characteristics.
That is, the inter-plane distance (d ₀₀₂ ) of the (002) plane is preferably 0.35 nm or less, more preferably 0.345 nm or less, and still more preferably 0.34 nm or less. Further, the size (Lc) of the crystallite in the c-axis direction is preferably 3.0 nm or more, more preferably 8.0 nm.
The thickness is more preferably 25.0 nm or more. The carbon material has an average particle size of 8 to 20 μm, particularly 10 μm.
The purity is preferably 99.9% by weight or more.

The negative electrode is prepared, for example, by adding the same conductive aid and binder as in the case of the positive electrode to the negative electrode active material, if necessary, mixing to prepare a negative electrode mixture, and dispersing it in a solvent. Paste (the binder may be dissolved in a solvent beforehand and then mixed with the negative electrode active material, etc.), and the negative electrode mixture-containing paste is applied to a negative electrode current collector composed of a metal foil such as a copper foil or a nickel foil. Then, it is dried to form a negative electrode mixture layer on at least a part of the negative electrode current collector, and if necessary, pressure-molding to perform a thickness control step. However, the method for manufacturing the negative electrode is not limited to the method described above, and may be another method.

As the current collector for the positive electrode and the negative electrode, for example, metal foils such as aluminum foil, nickel foil, copper foil, and stainless steel foil, and nets of these metals are used. A nickel foil or an aluminum foil is particularly suitable as the electric material, and a copper foil is particularly suitable as the current collector for the negative electrode.

When a carbon material is used for the negative electrode,
The density of the negative electrode mixture layer of the negative electrode is preferably set to 1.45 g / cm ³ or more from the viewpoint of increasing the capacity, more preferably 1.5 g / cm ³ or more. Normally, when the density of the negative electrode mixture layer is increased, a high capacity is easily obtained, but the permeation of the electrolyte is slow, and the utilization of the active material is also likely to be non-uniform, so that the cycle characteristics are easily deteriorated. However, in such a case, if the compound having a C ＝ C unsaturated bond as described above is contained in the electrolyte, the cycle characteristics may be reduced even when the density of the negative electrode mixture layer is increased. Can be suppressed.

[0028]

Next, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to only these examples. Also, in the following examples,
The percentages indicating the concentration of the solution or the dispersion or the percentages indicating the composition, the yield and the like are also percentages on a weight basis unless otherwise specified.

Example 1 First, the synthesis of carbon polysulfide used as a positive electrode active material in producing a positive electrode will be described.

Synthesis of carbon polysulfide: A mixed solvent of ethanol and water in which 100 g of sodium sulfide nonahydrate (Na ₂ S.9H ₂ O) was mixed at a volume ratio of 1: 1
and 53.4 g of elemental sulfur was added thereto and reacted at room temperature for 1 hour. The solvent is then removed in vacuo, and the residue is washed with N-methyl-2-pyrrolidone 70
0 ml, and hexachlorobutadiene was added to 17.2 ml.
g was added and reacted at room temperature for 1 hour. Thereafter, the solid was repeatedly washed three times in the order of pure water, acetone, and ethanol, and dried for 15 hours in vacuum at 40 ° C. to obtain a brown solid compound as an intermediate product. The yield of this brown solid compound was 32 g.

The obtained compound was subjected to elemental analysis,
The average composition was determined. For C, N, and H, a fully automatic elemental analyzer [vario EL manufactured by Siebel Hegna KK]
(Trade name)], analysis was performed under the conditions of a sample decomposition furnace temperature: 950 ° C., a reduction furnace temperature: 500 ° C., a helium flow rate: 200 ml / min, and an oxygen flow rate: 20 to 25 ml / min. In addition, S was analyzed by flask combustion method-barium acetate titration using trimethylene blue as an indicator. As a result, C: 7.0%, S: 92.3%,
It was found that N: 0.2% or less, H: 0.3% or less (N and H are less than the lower limit of quantification). The corresponding general formula was ( _CS4.9 ) _n .

Next, 10 g of the above intermediate product consisting of the brown solid compound was added to hull-shaped alumina (aluminum oxide).
The alumina container containing the intermediate product was placed in the core of the alumina heating furnace, and the oxygen concentration was 100 ppm.
After purging with an argon gas having a purity of 99.999% until the temperature becomes below, a heat treatment was performed at 380 ° C. while changing the temperature while flowing the argon gas. That is, from room temperature to 60 ° C
Temperature in 0.5 hours, hold at 60 ° C. for 1 hour, then heat up to 380 ° C. in 2 hours, hold at 380 ° C. for 1 hour to remove some of the sulfur in the intermediate product Thus, the intermediate product was changed to carbon polysulfide.

After cooling to room temperature after the treatment, the reaction product was taken out of the alumina container to obtain about 3 g of carbon polysulfide having a black metallic luster. As a result of elemental analysis, the general formula corresponding to the above-mentioned carbon polysulfide is (CS _1.06 ) _n
Met. Hexachlorobutadiene used as a reaction component in the synthesis of the above-mentioned carbon polysulfide has 4 carbon atoms.
Therefore, the n value of the above (CS _1.06 ) _n is 4 or more, and it is considered that a molecule having a multiple of 4 is mainly synthesized.

Next, Raman analysis was performed on the carbon polysulfide. The Raman analysis apparatus and conditions are as follows. Apparatus: Ramaonor T-6400 (Jobin Yvon / Atago Bussan) Measurement conditions: Light source: Ar laser, 514.5 nm (NEC GLG3460) Laser power: 1 mW

As a result of Raman analysis, the carbon sulfide
Is 400 cm in Raman shift^-1~ 525cm
^-1490cm between^-1With one peak at 1444
cm ^-1Had a strong peak. 490 above
cm^-1Is the peak of -CSSC-segment in the molecule.
And 1444c
m^-1Is the peak of the carbon unsaturated bond (C =
400 cm based on C)^-1~ 525cm^-1
That there is essentially only one peak between
Pi corresponding to the bond corresponding to the resulfide segment
This indicates that no work exists.

The carbon polysulfide was subjected to X-ray diffraction measurement using a powder X-ray diffractometer [RINT2000 (trade name) manufactured by Rigaku Corporation] using CuKα radiation. The measurement conditions were as follows: voltage: 40 kV, current: 150 mA,
Scan speed: 2 ° / min, sampling: 0.02 °,
Number of integration: 5 times. The X-ray diffraction pattern of the carbon polysulfide obtained by this X-ray diffraction measurement was 25.5 °.
Had only a broad main peak.

Preparation of positive electrode: The positive electrode was prepared as follows. That is, 10 g of carbon polysulfide represented by the above general formula (CS _1.06 ) _n , 7.2 g of graphite [KS-6 (trade name), manufactured by Lonza Co., Ltd.] and 0.8 g of acetylene black are placed in a mixing vessel. Put, dry 10
After mixing for 50 minutes, 50 g of N-methyl-2-pyrrolidone was added and mixed for 30 minutes. Next, an N-methyl-2-pyrrolidone solution 1 containing 12% of polyvinylidene fluoride
6.7 g was added and mixed for an additional hour to prepare a positive electrode mixture-containing paste.

The obtained positive electrode mixture-containing paste was coated to a thickness of 10
μm nickel foil (size: 250 mm x 220 mm)
And dried on a hot plate at 50 ° C. for 10 minutes, and further dried in vacuum at 120 ° C. for 10 hours to obtain N
-Methyl-2-pyrrolidone was removed to form a positive electrode mixture layer, which was then subjected to pressure molding at room temperature to reduce the thickness of the positive electrode mixture layer to 20.
It was adjusted to μm to obtain a positive electrode.

Preparation of Negative Electrode: The negative electrode was prepared by placing a 200 μm-thick metallic lithium foil on a nickel net (size: 250 mm × 220 mm) in an argon gas atmosphere and pressing with a roller.

Synthesis of lithium salt of polysulfide: As the lithium salt of polysulfide, Li ₂ S ₈ is synthesized as shown below. The synthesis is performed in an electrolytic solution.
Li ₂ S ₈ was synthesized so that the electrolyte contained 0.5 mol / l. As the electrolytic solution, a solution prepared by dissolving LiCF ₃ SO ₃ at a concentration of 1 mol / l in a mixed solvent of tetraethylene glycol methyl ether (tetraglyme) and 1,3-dioxolane at a volume ratio of 1: 1 was used.

Then, in an atmosphere protected from moisture.
2.3 g of Li in 5 g of the above electrolyte_TwoS and 11.2g
Of elemental sulfur and refluxed at 80 ° C. for 5 hours to obtain Li
_TwoS ₈Was synthesized. Li in electrolyte_TwoS₈The content of
0.5 mol / l, and this Li_TwoS₈With the synthesis of
LiCF in electrolyte_ThreeSO_Three0.87mol
/ L.

Battery assembly: The above positive electrode and negative electrode were
via a separator made μm polypropylene nonwoven laminated in an argon gas atmosphere, nylon film and the laminated electrode body - aluminum foil - placed in a package consisting of three-layer laminate film of modified polyolefin resin film, the Li ₂ S ₈ After injecting an electrolytic solution containing, a non-aqueous secondary battery was assembled by sealing.

A positive electrode active material (combination of (CS _1.06 ) _n of polysulfide and Li ₂ S ₈ ) was added to the above battery.
The battery was discharged to 1.5 V at a current value equivalent to 60 mA per g, and charged at a constant current and constant voltage (voltage: 2.5 V) at the same current value. And the discharge capacity at the 50th cycle were measured, and the change in the discharge capacity per unit weight of the positive electrode active material was examined. The results are shown in Table 1 below. Each of the discharge capacities shown in Table 1 is a discharge capacity per 1 g of the positive electrode active material.

Example 2 The electrolyte was the same as in Example 1, but the Li in the electrolyte was
The content of ₂ S ₈ except that the 1.0 mol / l, to prepare a non-aqueous secondary battery in the same manner as in Example 1.

Example 3 The constituent solvent of the electrolytic solution was changed to a mixed solvent of dimethyl sulfoxide and 1,3-dioxolane at a volume ratio of 1: 1 and the content of Li ₂ S ₈ in the electrolytic solution was changed to 1.0 mol / mol. A non-aqueous secondary battery was fabricated in the same manner as in Example 1 except that the value was changed to 1.

Example 4 In preparing a positive electrode, the positive electrode active material was represented by the general formula (CS _1.06 )
_{From the} carbon polysulfide represented by _n , the general formula (CS _1.35 )
_A non-aqueous secondary battery was produced in the same manner as in Example 1, except that the carbon polysulfide represented by _n was used.

The batteries of Examples 2 to 4 were charged and discharged in the same manner as in Example 1.
The discharge capacity at the cycle was examined. Table 1 shows the results.

Comparative Example 1 A non-aqueous secondary battery was fabricated in the same manner as in Example 1, except that Li ₂ S was dissolved in the electrolyte instead of Li ₂ S ₈ . When the battery of Comparative Example 1 was charged and discharged in the same manner as in Example 1, Li ₂ S did not contribute to the charging and discharging. Therefore, the positive electrode active material [(CS _1.06 ) _{n of} polysulfide carbon and Li
Combined with ₂ S ₂ ] The discharge capacity per 1 g is 1
Only 210 mAh / g was obtained in the cycle.

Comparative Example 2 In preparing a positive electrode, a general formula (CS) was used as a positive electrode active material.
_1.06 ) Instead of the carbon sulfide represented by _n , a carbon sulfide represented by the general formula (CS _4.9 ) _n is used, and dimethyl sulfoxide and 1,1,
Using a constituent solvent having a volume ratio of 1: 1 with 3-dioxolane,
The content of Li ₂ S ₈ contained in the electrolytic solution is set to 1.0 mo.
A non-aqueous secondary battery was produced in the same manner as in Example 1 except that the amount was changed to 1 / l. When the battery of Comparative Example 2 was charged and discharged in the same manner as in Example 1, the positive electrode collapsed in the second cycle, so that charging and discharging after the second cycle became difficult.

COMPARATIVE EXAMPLE 3 The positive electrode was changed to a carbon electrode, the constituent solvent of dimethyl sulfoxide and 1,3-dioxolane was changed to a constituent solvent having a volume ratio of 1: 1 as a constituent solvent of the electrolytic solution, and Li ₂ was contained in the electrolytic solution.
Except for changing the content of S ₈ in 1.0 mol / l was used to fabricate a non-aqueous secondary battery in the same manner as in Example 1. The composition of the carbon electrode in the battery of Comparative Example 3 was 82% of graphite [KS-6 (trade name), manufactured by Lonza], 8% of acetylene black, and 10% of polyvinylidene fluoride. The battery of Comparative Example 3 was charged and discharged in the same manner as in Example 1. As a result, at the first cycle, 167 batteries / g of the positive electrode active material were used.
Since only a discharge capacity of mAh / g was obtained and the positive electrode (carbon electrode) collapsed in the second cycle, charging and discharging in the second and subsequent cycles were difficult.

Table 1 shows the discharge capacity at the first cycle and the discharge capacity at the 50th cycle of the batteries of Examples 1 to 4.

[0052]

[Table 1]

As is clear from the results shown in Table 1,
The batteries of Examples 1 to 4 have large first-cycle discharge capacities,
High capacity and large discharge capacity at 50th cycle
Less deterioration even after 50 charge / discharge cycles,
The cycle characteristics were excellent. In contrast, in the electrolyte
Li_TwoS₈Instead of Li_TwoComparative Example 1 containing S
As described above, the pond has a discharge capacity of 210 cycles in the first cycle.
mAh / g was obtained, and the general formula (CS_1.06)
_nOnly properties based on carbon polysulfide represented by
Was. Also, when producing a positive electrode, one
General formula (CS_4.9) _nUsing carbon polysulfide shown by
Using the battery of Comparative Example 2 and a carbon electrode for the positive electrode
When the battery of Example 3 was repeatedly charged and discharged, as described above, 2
Positive electrode collapse occurs at cycle, poor cycle characteristics
Was. In particular, the battery of Comparative Example 3 using a carbon electrode for the positive electrode
Has a small capacity in the first cycle and is contained in the electrolyte.
Li _TwoS₈Was not activated.

[0054]

As described above, according to the present invention, a non-aqueous secondary battery having a high capacity and excellent cycle characteristics can be provided. In addition, the present invention can be applied to a primary battery, and a primary battery can provide a high-capacity nonaqueous battery as in the case of a secondary battery.

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Yoshishi Iizuka 1-88 Ushitora, Ibaraki-shi, Osaka F-term within Hitachi Maxell Co., Ltd. 5H024 AA01 FF15 FF16 FF17 FF18 FF19 FF20 HH00 5H029 AJ03 AJ05 AK01 AL06 AM03 AM04 AM05 AM06 AM07 HJ02 5H050 AA07 AA08 BA06 BA17 CA01 CB07 EA10 EA24 HA02

Claims (2)

[Claims] 1. The general formula (CS _x ) _n (x is 0.5 to 1.
5, n is 4 or more) having a positive electrode using carbon polysulfide as a positive electrode active material, a negative electrode, and a non-aqueous electrolytic solution, wherein a lithium salt of polysulfide is contained in the electrolytic solution. Non-aqueous battery characterized by containing. 2. The lithium salt of polysulfide,
Formula Li ₂ S _m ((wherein, the non-aqueous battery according to claim 1, wherein m is a lithium salt of polysulfide represented by a number of 2 or more).