KR100387394B1 - Organopolysulfide, cathode active material comprising the same and lithium battery employing the cathode active material - Google Patents

Abstract

The present invention discloses an organopolysulfide, a cathode active material comprising the same, and a lithium battery employing the same, which is a result of a reaction between a compound of Formula 1 and a sulfur monochloride.

<Formula 1>

In the above formula, R is hydrogen or CH ₃ .

Use of the cathode active material containing the organopolysulfide of the present invention is excellent in electrochemical properties. Such organopolysulfide may be usefully used as a potential vulcanization material in addition to the cathode active material.

Description

Organopolysulfide, cathode active material comprising the same and lithium battery employing the same {Organopolysulfide, cathode active material comprising the same and lithium battery employing the cathode active material}

The present invention relates to an organopolysulfide, a cathode active material comprising the same and a lithium battery employing the same, and more particularly, by employing an organopolysulfide, a cathode active material having excellent electrochemical properties and excellent performance by employing the same. It relates to a lithium battery.

With the rapid increase in the use of portable devices, the demand for high performance rechargeable batteries is increasing. In addition, the miniaturization of such portable devices adds to the need for development of secondary batteries having light weight and high energy density characteristics.

However, in the case of the conventional secondary battery, the light weight and the high capacity have been achieved to some extent, but due to the environmental problems caused by the use of heavy metal, a secondary battery using an environmentally friendly material is urgently required.

On the other hand, one of the important factors in realizing a high capacity battery is an urgent problem to develop an electrode active material having a low equivalent weight (equivalent weight). At this time, the electrode active material should have good ion conductivity and have high reversibility in oxidation and reduction reactions. In addition, the thermal and chemical stability and low cost of the material must be sufficient to supply the material, there is no toxicity and easy to manufacture.

As the cathode active material satisfying the above-mentioned characteristics, the following organic sulfur compounds are known.

Polyplus Battery Company, Inc. has developed (R (S) _y ) _n (where y is 1 to 6 and n is 2 to 20) as an organic sulfur cathode active material. However, when the cathode active material is used, there is a problem in that the battery has excellent energy density but poor life characteristics.

The organic sulfur cathode active materials disclosed in U.S. Patent No. 5,686,201 and U.S. Patent No. 5,532,077 have excellent energy density characteristics, but have poor cycle characteristics and require 150% of the discharge capacitance to be charged. low.

Cathode active materials developed by Moltech Corporation include (CS _x ) _n (where x is 1.7-2.3 and n is 2-20) and (C ₂ S _x ) _n (where x is 1-10 , n ≧ 2) (US Pat. No. 5,529,860). These cathode active materials have a high theoretical specific capacity, but have low utilization rates and low reversibility to oxidation and reduction reactions, that is, charging and discharging reactions, and an amount of sulfur participating in the electrochemical reaction by forming an insulating sulfur film at the electrode site. There is a problem that the capacitance efficiency is relatively low because it is limited.

The technical problem to be achieved by the present invention is to solve the above problems to provide a novel organopolysulfide compound that can be used as a cathode active material not only excellent in electrochemical properties but also highly reversible to the charge and discharge reaction.

Another object of the present invention is to provide a cathode active material including the novel organopolysulfide compounds.

Another technical problem to be achieved by the present invention is to provide a lithium battery having excellent performance by employing the cathode active material.

1 is a graph showing the thermogravimetric analysis of the organopolysulfide prepared according to Synthesis Example 3 of the present invention,

2 is a view showing the mass spectrometry results of the organopolysulfide prepared according to Synthesis Example 3 of the present invention,

3 is a graph showing charge and discharge characteristics of a lithium battery using an organopolysulfide prepared according to Synthesis Example 3 of the present invention.

In order to achieve the first technical problem, the present invention provides an organopolysulfide, which is a result of a reaction between a compound of Formula 1 and a sulfur monochloride.

<Formula 1 >>

In the above formula, R is hydrogen or CH ₃ .

The formula of the reaction product between the compound of formula 1 wherein R is hydrogen and the sulfur monochloride is (C ₁₄ H ₁₀ O ₂ S ₈ ) _n is represented by the following formula (2). In addition, the synthetic formula of the reaction product between the compound of formula 1 and sulfur monochloride wherein R is a methyl group is (C ₁₄ H ₁₀ O ₂ S ₈ ) _n , and is represented by the following formula (3).

<Formula 2>

<Formula 3>

The first technical problem of the present invention is also made by an organopolysulfide, characterized in that represented by the formula (4).

<Formula 4>

The formula of the organopolysulfide of the formula (4) is C ₆ H ₁₈ , which is the result of the reaction of hexabromobenzene and sulfur in the presence of ammonia.

The second technical problem of the present invention is to provide a cathode active material comprising the organopolysulfide of the formula (2) to (4).

The third technical problem of the present invention is achieved by a lithium battery employing the cathode active material.

The present invention is intended to make an environmentally friendly battery by replacing heavy metal materials of nickel, cobalt, and manganese, which are used as cathode active materials of conventional secondary batteries, with sulfur compounds of nonmetals.

Sulfur compounds are generally available as high-capacity active materials, but are known to be difficult to control the particle size, thereby lowering the electrochemical utilization.

However, the organopolysulfide according to the present invention has good electrochemical utilization and excellent specific capacity characteristics.

When using LiCoO ₂ , LiNiO ₂ , LiMn ₂ O _4, or a composite metal oxide thereof as a cathode active material in a conventional secondary battery, the battery voltage range is 3.5 to 3.7V.

On the other hand, using the organopolysulfides of the formulas (2) to (4) according to the invention as a cathode active material exhibits a battery voltage of about 2V for lithium. Since the voltage of 2V is in the potential window range that is stable with respect to the conventional solid polymer electrolyte, most solid polymer electrolytes can be applied without a large change in the voltage change range.

The present invention provides an organopolysulfide which is a result of the reaction between the compound of formula 1 and sulfur monochloride.

<Formula 1>

In the above formula, R is hydrogen or CH ₃ .

When R in formula 1 is hydrogen, the formula of the reaction product between the compound and the sulfur monochloride is (C ₁₄ H ₁₀ O ₂ S ₈ ) n, which is represented by the formula (2), wherein n is 1 or 2 to be)

<Formula 2>

In the above Formula 1, when R is a methyl group, the formula of the reaction product between the compound and the sulfur monochloride is (C ₁₄ H ₁₀ O ₂ S ₈ ) _n, and is represented by Formula 3 (where n is 1 or 2). ).

<Formula 3>

The present invention also provides an organopolysulfide represented by the formula (4), which can be prepared by reacting hexabromobenzene and sulfur in the presence of ammonia, as can be seen from the following scheme.

<Formula 4>

The formula of the organopolysulfide is C6S18.

The organopolysulfides of Chemical Formulas 2 to 4 may be used as cathode active materials, and may be usefully used as potential vulcanizing materials.

In the lithium secondary battery according to the present invention, the solid polymer electrolyte functions as a conductive medium of lithium ions and a separator (separation membrane).

Hereinafter, a battery employing the organopolysulfides of Chemical Formulas 2 to 4 as a cathode active material will be described.

First, a cathode active material composition is prepared by adding a conductive agent, a binder, a lithium salt, and a solvent to one of the organopolysulfides selected from Formulas 2 to 4, which are cathode active materials, and sufficiently mixing them. The cathode is then prepared by coating and drying the cathode active material composition on a cathode current collector to form a cathode active material layer.

In the cathode active material composition, carbon black, acetylene black, or vapor growth carbon (VGCF) may be used as the conductive agent. The content of the conductive agent is 5 to 20 parts by weight, more preferably 13 to 17 parts by weight, most preferably 15 parts by weight based on 100 parts by weight of the total weight of the solid content of the cathode active material composition. In this case, when the content of the conductive agent exceeds 20 parts by weight, it is difficult to cast the composition for forming the active material on the cathode current collector, and the content of the cathode active material is relatively decreased. When the content is less than 5 parts by weight, the resistance of the cathode This problem is difficult to charge and discharge.

As the binder, it is preferable to use the same material as the polymer resin for forming the polymer matrix used as the separator. Specific examples of such binders include polyethylene oxide (PEO), polyacrylonitrile (PAN), polymethyl methacrylate (PMMA), polyvinylidene fluoride (PVDF), acrylonitrile-methyl methacrylate-styrene terpolymer (Acrylonitrile-Methylmethacrylate-Styrene terpolymer: AMS), vinylidene fluoride-hexafluoropropylene copolymer (PVDF-HFP copolymer), polyvinyl chloride (PVC) and cellulose, and the content of the binder is a cathode active material solids 10 to 35 parts by weight is used based on 100 parts by weight of the total weight, more preferably 20 to 32 parts by weight. In this case, when the content of the binder exceeds 35 parts by weight, the content of the cathode active material, which is one selected from Formulas 2 to 4, is relatively reduced. When the content is less than 10 parts by weight, the content of the conduction medium of lithium ions is reduced. The conductivity of lithium ions is reduced. As a result, the cathode has a large resistance, which makes it difficult to charge and discharge, which is not preferable.

The content of one compound selected from Formulas 2 to 4, which is the cathode active material, is 55 to 90 parts by weight, more preferably 55 to 70 parts by weight, most preferably based on 100 parts by weight of the total solids of the cathode active material composition. About 65 parts by weight. In this case, when the content of the cathode active material exceeds 90 parts by weight, the content of the conductive agent, the binder, and the lithium salt is relatively insufficient, making it difficult to conduct electrons and lithium ions, thereby increasing electrode resistance and making charging and discharging difficult. If the amount is less than the amount, the content of the cathode active material in the electrode is relatively small, so that the specific capacity of the electrode is reduced, which is not preferable.

The lithium salt is not particularly limited as long as it is a lithium compound that is dissociated in an organic solvent to produce lithium ions. Specific examples thereof include lithium perchlorate (LiClO ₄ ), lithium tetrafluoroborate (LiBF ₄ ), and Group consisting of lithium hexafluorophosphate (LiPF ₆ ), lithium trifluoromethansulfonate (LiCF ₃ SO ₃ ) and lithium bistrifluoromethansulfonylamide (LiN (CF ₃ SO ₂ ) ₂ ) It is preferable to use at least one ionic lithium salt selected from 2 to 4 parts by weight based on 100 parts by weight of the total weight of solids of the cathode active material composition, if the content of lithium salt exceeds 4 parts by weight lithium ion The ionization efficiency of the decreases, there is a problem that the lithium salt is precipitated during the manufacturing of the cathode, If it is less than 2 parts by weight, it is not preferable because the concentration of lithium ions in the cathode is reduced.

As the solvent, a binder and a lithium salt may be dissolved, a cathode active material and a conductive agent may be dispersed, and any material that can be easily volatilized may be used, and acetonitrile and N-methylpyrrolidone may be used. , Dimethylformamide, hexane, acetone and the like are used. And the content was used 250 to 730 parts by weight based on 100 parts by weight of total solids in the cathode active material composition. In the case where the content of the solvent exceeds 730 parts by weight, the viscosity of the cathode active material composition becomes small, making it difficult to cast the composition. If the content is less than 250 parts by weight, the composition of the cathode active material composition may be cast due to high heterogeneity and high viscosity. Becomes difficult.

Separately, an anode is formed by roll-pressing a lithium metal or a lithium alloy as an anode active material on the anode current collector to form an anode active material layer. In this case, it is also possible to add an additive such as a conductive agent and a binder to lithium metal or an alloy similarly to the cathode.

A separator is interposed between the cathode and the anode, and then stacked in this order and sealed under vacuum conditions. Subsequently, the lithium secondary battery is completed by aging the sealed battery.

The lithium battery of the present invention is not particularly limited, but a lithium / sulfur polymer electrolyte battery using a solid polymer electrolyte as a separator is particularly preferable.

As the solid polymer electrolyte, commercially available porous polypropylene (trade name: Celgard 2500), porous polyethylene, and an electrolyte made by impregnating an electrolyte solution with a porous polyethylene-polypropylene multilayer membrane are used. In this case, the electrolyte is composed of a lithium salt and an organic solvent, and the lithium salt uses the same kind as the lithium salt used in the composition for forming the cathode active material. As the organic solvent, propylene carbonate (PC) and ethylene carbonate ( ethylene carbonate: EC), γ-butyrolactone, 1,3-dioxolane, 1,3-dioxolane, dimethoxyethane, dimethyl carbonate (DMC), diethyl carbonate at least one solvent selected from diethylcarbonate (DEC), methylethylcarbonate (MEC), tetrahydrofuran (THF), dimethylsulfoxide and polyethyleneglycol dimethylether is used. And the content of lithium salts and solvents is the usual level used in lithium batteries.

In addition, the solid polymer electrolyte of the present invention may be used in addition to the above-described one prepared according to the following method.

First, a solid polymer electrolyte composition is prepared by mixing a polymer resin, a filler, a solvent, and a lithium salt. The composition may be directly coated and dried on the anode to form a solid polymer electrolyte composition to obtain a solid polymer electrolyte, or the solid polymer electrolyte composition may be cast on a separate support and dried, and then peeled off from the support. The solid polymer electrolyte film can be formed by laminating on the anode. Herein, the support may be used as long as it has a function of supporting a solid polymer electrolyte film, and a glass substrate, a polyethylene terephthalate (PET) film, a mylar film, and the like are used.

The polymer resin is not particularly limited, but any material used for the binder of the cathode may be used. These include polyethylene oxide (PEO), polyacrylonitrile (PAN), polymethyl methacrylate (PMMA), polyvinylidene fluoride (PVDF), acrylonitrile-methyl methacrylate-styrene terpolymer (AMS), Vinylidene fluoride-hexafluoropropylene copolymer (VDF-HFP copolymer), polyvinyl chloride (PVC), cellulose, etc. can be used.

As the filler to improve the mechanical strength of the solid polymer electrolyte, silica, kaolin, alumina, zeolite and the like are used. And the content of the filler is preferably 2 to 10 parts by weight, more preferably 5 parts by weight based on 100 parts by weight of the total weight of solids of the composition for forming a solid polymer electrolyte. When the content of the filler is less than 2 parts by weight, the ionic conductivity and mechanical properties of the solid polymer electrolyte are lowered, and when the content of the filler is more than 10 parts by weight, the film filmability is poor, which is not preferable.

In addition, the solvent in the composition for forming a solid polymer electrolyte may be acetonitrile, N-methylpyrrolidone, dimethylformamide, hexane, acetone, or the like as a material capable of dissolving or dispersing a polymer resin, a filler, and a lithium salt. The content thereof is preferably 1000 to 1500 parts by weight based on 100 parts by weight of the total solid weight of the composition for forming a solid polymer electrolyte, and when the content of the solvent is less than 1000 parts by weight, there are problems in terms of dispersion, casting and uniformity of the composition. When the amount exceeds 1500 parts by weight, casting of the composition and controlling the film thickness become difficult.

In the above-mentioned composition for forming a solid polymer electrolyte, the lithium salt may be the same kind as the lithium salt added to the cathode. The content thereof is 5 to 15 parts by weight based on 100 parts by weight of the total weight of solids of the composition for forming a solid polymer electrolyte. If the content of the lithium salt is less than 5 parts by weight, there is a problem that the ionic conductivity of the solid polymer electrolyte is lowered. If the content of the lithium salt is more than 15 parts by weight, dissociation of the lithium salt becomes difficult and the film formability is poor.

In the lithium / sulfur polymer electrolyte battery according to the present invention, an organopolysulfide which is a cathode active material, that is, an organopolysulfide selected from Chemical Formulas 2 to 4, is reacted with an organopoly (M) as an anode material during a discharge process. To form a metal-sulfur compound in the sulfide.

x / zM + S = Mx / zS

That is, during the discharging process, the cathode is composed of a combination of organopolysulfide, metal, sulfur, and the like, and the discharging and charging process is reversible.

Hereinafter, the present invention will be described in detail with reference to the following synthesis examples and examples, but the present invention is not limited only to the following examples.

Synthesis Example 1. Preparation of organopolysulfide represented by Chemical Formula 2

(1) When the molar ratio of 4,4'-ethylidenebisphenol (4,4'-Ethylidenebisphenol) and SMC is 1: 4. 4,4'-Ethylidenebisphenol (10 mmol, 2.14 g) was dissolved in 40 mL of MC, cooled in an ice water bath, and then 4 equivalents of SMC (40 mmol, 3.2 mL) was added over 1 minute. In order to remove toxic gases such as Cl2 and HCl generated in this reaction, NaOH traps were attached and installed at the inlet of the reaction flask to remove toxic gases.

At the beginning of the stirring the reaction mixture turned red and was not as cloudy as bisphenol A. However, when the temperature of the ice bath was raised to room temperature and stirred for 1 hour, a red precipitate precipitated out of the reaction mixture. After 7 days, a purple-red solid was formed.

The solid was filtered, washed with methylene chloride and the filtered solid was dried in vacuo at 80 ° C. to obtain a purple solid. The melting point of this purple solid was measured. In addition, the sulfur content in the purple solid was measured by elemental analysis (Elemental Anaylsis).

As a result of the analysis, the purple solid was slightly discolored near 240 ° C. and did not melt even at 260 ° C. and remained purple. The elemental analysis showed that the ratio carbon: hydrogen: oxygen: sulfur was 41.8: 2.49: 5.76: 47.3. As a result, it is expected that the (C ₁₄ H ₁₀ O ₂ S ₈ ) _n bistetrasulfide system. (n = 1 or 2)

(2) When the molar ratio of 4,4'-ethylidenebisphenol and SMC is 1: 8

4,4'-Ethylidenebisphenol (4,4'-Ethylidenebisphenol) (10 mmol, 2.14 g) was dissolved in 40 mL of MC and 8 equivalents of SMC (80 mmol, 6.4 mL) was added in an ice water bath over 1 minute. To remove toxic gases, NaOH traps were attached to the inlet of the flask to remove rapidly generated toxic gases.

The reaction mixture turned red from the beginning of stirring and the solution was not clouded like Bisphenol A. In addition, the red precipitate was not precipitated from the reaction mixture even after gradually raising the temperature of the ice bath to room temperature and stirring for about 1 hour. A precipitate was formed late compared to the case where the molar ratio of 4,4'-ethylidenebisphenol (4,4'-Ethylidenebisphenol) and SMC was 1: 4, and the reaction was terminated after 7 days to obtain a purple-red solid. The solid thus produced was filtered and washed with methylene chloride and dried in vacuo at 80 ° C. to obtain a purple solid.

The melting point of the purple solid obtained according to the above procedure was measured.

As a result of the measurement, the melting point of the solid was slightly discolored around 240 ° C., similar to the experiment of (1), and the color remained insoluble and brownish purple at 260 ° C.

On the other hand, the sulfur content of the purple solid obtained according to the above process was measured by elemental analysis.

As a result, the ratio carbon: hydrogen: oxygen: sulfur was 38.36: 2.17: 5.51: 51.44. Therefore, considering the experimental error of elemental analysis, it is (C ₁₄ H ₁₀ O ₂ S ₈ ) _n bistetrasulfide which is the same substance as in (1) (n = 1 or 2).

From the above results, the melting point of the organopolysulfide represented by the formula (2) is 260 ° C or more. The theoretical capacity estimate is 690 mAh / g (if Sulfur only participates in capacity) and 805 mAh / g if the alcohol group accepts Li.

Synthesis Example 2 Preparation of Organopolysulfide Represented by Chemical Formula 3

(1) The molar ratio of bisphenol A and SMC is 1: 4.

Bisphenol A (10 mmol, 2.28 g) was dissolved in 40 mL of methylene chloride and 4 equivalents of SMC (40 mmol, 3.2 mL) was added in an ice water bath over 1 minute. Stirring the reaction mixture for 1 minute produced a white solid and the reaction mixture became cloudy. Subsequently, the temperature of the reaction mixture was gradually raised to room temperature, and reacted for 7 days with stirring.

After 7 days, a dark yellow solid was formed in the reaction mixture. The solid was filtered off, washed with methanol and the filtered solid was vacuum dried at 80 ° C. The melting point of the dark yellow solid obtained by vacuum drying was measured.

As a result of the measurement, the melting point of the solid was changed to light brown at around 220 ° C., and discolored to brown at 260 ° C. without melting.

On the other hand, the sulfur content of the solid was measured by elemental analysis.

The elemental analysis showed that the ratio carbon: hydrogen: oxygen: sulfur was 42.09: 2.91: 5.83: 47.30.

(2) when the molar ratio of bisphenol A and SMC is 1: 8

The reaction was carried out according to the same method as the case of (1), except that the use amount of SMC was changed to 8 equivalents (80 mmol, 6.4 mL) to obtain a dark yellow solid.

The melting point of the solid was measured, and the melting point of the dark yellow solid was changed to light brown near 220 ° C., and discolored to brown without melting at 260 ° C.

On the other hand, the solid was analyzed using elemental analysis, and the carbon: hydrogen: oxygen: sulfur ratio was 39.87: 2.75: 5.90: 55.77. From these elemental analysis results, considering the experimental error of elemental analysis, the final product is (C ₁₅ H ₁₂ O ₂ S ₈ ) _n bistetrasulfide (n = 1 or 2). The estimated theoretical capacity of the organopolysulfide represented by the formula (3) is 670 mAh / g (when participating in the sulfur only capacity) and 780 mAh / g when the alcohol group accepts Li.

Synthesis Example 3 Preparation of Organopolysulfide Represented by Chemical Formula 4

C ₆ Br ₆ (Hexabromobenzene, 4 mmol, 2.206 g) and sulfur atom (Sulfur-atom) (6.4 g) were reacted at 100 ° C. and 400 rpm for 24 hours in the presence of ammonia (240 mL) in a 500 mL high pressure reactor.

After 24 hours of reaction, the temperature of the reaction mixture was adjusted to 80 ° C., and a tube was attached to the inlet of the high-pressure reactor, and the ammonia-containing liquid in the reaction mixture was transferred to a 1 L round flask containing 500 mL of methylene chloride by jet-jetting.

Subsequently, after ammonia was completely evaporated from the methylene chloride solution, it was filtered using a cannula equipped with a paper filter. The solid obtained by filtration was dried and subjected to thermogravimetric analysis (TGA).

As a result, the solid had 99.00% at 136 ° C, 98.00% at 156.43 ° C, 95.00% at 183 ° C, and 25.76% residue at 300 ° C.

On the other hand, the red solid remaining after the filtration using the Kennull was washed with 500mL of methanol, 250mL of acetone to remove traces of unreacted sulfur and by-products of ammonia. The reddish brown powder obtained according to the above procedure was dried in a vacuum oven at 60 ° C. for 5 hours to obtain 1.07 g of organopolysulfide, which was subjected to elemental analysis.

According to the elemental analysis, nitrogen: 0.68:%, carbon: 11.56%, hydrogen: 0.32%, sulfur: 90.00%, and trace nitrogen and hydrogen components exist, but the carbon: sulfur weight ratio is 11.56: 90, so that 6 carbons Since it exists, there were 18 sulfur.

The expected theoretical capacity of the organopolysulfide represented by Formula 4 is 1250 mAh / g, and the thermal characterization of the synthesized organopolysulfide showed 0.52% of volatile components and melting point (T _m ) peaks at 116.9 ° C and 122.4 ° C. And the decomposition point (T _d ) peaks were onset at 223.3 ° C. and 275.9 ° C., and these results are shown in FIG. 1,

On the other hand, Figure 2 shows the GC-MASS analysis of the organopolysulfide prepared according to Synthesis Example 3. Referring to this, it was found that the organopolysulfide has an octagonal ring structure.

A lithium battery was constructed using the organopolysulfide, and a charge and discharge test was performed. The results are shown in FIG. 3. At this time, the charging and discharging conditions were initially 0.25C charged and 0.5C discharged.

Referring to FIG. 3, the charging capacity of the lithium battery was about 675 mAh / g and a 0.5C discharge capacity of 610 mAh / g.

As described above, the organopolysulfides of Chemical Formulas 2 to 4 are easy to process the particle size, have excellent electrochemical properties, especially capacity characteristics, and excellent stability to air, moisture, and heat. When the organopolysulfide is used as a cathode active material, it is possible to develop a lithium battery, in particular a lithium secondary battery, having a 2V class pollution-free high energy characteristic which is excellent in capacity and cycle characteristics. The lithium secondary battery is particularly suitable for the next generation of advanced electronic devices driven by 1.5-1.8V, which is widely applicable for small electronic devices such as civil, military, aerospace, and future-oriented. In addition, the lithium secondary battery of the present invention can be applied to high-power wireless equipment such as electric vehicles, submarines, electric vehicles, etc. because of the high capacity and high voltage.

On the other hand, the organopolysulfide of the formula (2) to 4 can be used as a potential vulcanization material in addition to the cathode active material described above.

Although the present invention has been described with reference to the above embodiments, it is merely illustrative, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. . Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Claims (8)

Organopolysulfide, characterized in that the result of the reaction between the compound of formula 1 and the sulfur monochloride: <Formula 1> In the above formula, R is hydrogen or CH ₃ . According to claim 1, wherein the formula of the reaction product between the compound of formula 1 and the sulfur monochloride wherein R is hydrogen is (C ₁₄ H ₁₀ O ₂ S ₈ ) _n , Organopolysulfide, characterized in that (C ₁₄ H ₁₀ O ₂ S ₈ ) _n The synthetic formula of the reaction product between the compound of formula 1 wherein R is a methyl group and the sulfur monochloride. According to claim 1, The reaction product between the compound of formula 1 and the sulfur monochloride wherein R is hydrogen is represented by the formula (2), Organopolysulfide, characterized in that the reaction product between the compound of formula (1) wherein R is a methyl group and the sulfur monochloride. <Formula 2> <Formula 3> Organopolysulfide, characterized in that represented by the formula (4). <Formula 4> The organopolysulfide according to claim 4, wherein the formula of organopolysulfide is C ₆ S ₁₈ . The organopolysulfide according to claim 4, wherein the organopolysulfide represented by the formula (4) is a result of reacting hexabromobenzene and sulfur in the presence of ammonia. A cathode active material comprising the organopolysulfide according to any one of claims 1 to 6. The lithium battery which employ | adopts the cathode active material containing the organopolysulfide of any one of Claims 1-6.