Crosslinked polythiophene compounds, sulfur-carbon complex, lithium-sulfur battery, and method of manufacturing the sulfur-carbon complex

Abstract

A sulfur-carbon composite comprising a cross-linked polythiophene compound having a cross-linked structure and containing a cationic functional group, a porous carbon material; a coating layer located on at least one surface of the porous carbon material and containing the cross-linked polythiophene compound; and a sulfur compound located on at least a portion of the surface of the porous carbon material or within a pore, or on the surface of the coating layer, and a lithium-sulfur battery comprising the sulfur-carbon composite are presented.

Description

Technology Field

[0001] The present invention relates to a cross-linked polythiophene compound capable of improving the lifespan of a battery by capturing polysulfides eluted from the anode, and a battery comprising the same.

[0002] This application is a priority claim application for Korean Patent Application No. 10-2022-0118937 filed on September 20, 2022, and all contents disclosed in the specification of said application are incorporated into this application by reference. Background Technology

[0004] With the increasing technological development and demand for mobile devices, the demand for secondary batteries as an energy source is rapidly rising. Among these secondary batteries, lithium secondary batteries, which exhibit high energy density and operating potential, long cycle life, and low self-discharge rate, have been commercialized and are widely used.

[0005] Furthermore, with the recent increase in interest in environmental issues, extensive research is being conducted on electric vehicles (EVs) and hybrid electric vehicles (HEVs) that can replace fossil fuel-using vehicles, such as gasoline and diesel cars, which are major causes of air pollution. Lithium-ion batteries, characterized by high energy density, high discharge voltage, and output stability, are primarily being researched and used as the power source for these electric and hybrid electric vehicles.

[0006] A lithium secondary battery is structured such that a non-aqueous electrolyte containing a lithium salt is impregnated into an electrode assembly in which a porous separator is interposed between a positive electrode and a negative electrode, each having an active material coated on an electrode current collector.

[0007] Currently, the lithium secondary battery market is dominated by technology based on the pairing of lithium cobalt oxide (LiCoO2) in the cathode and graphite in the anode. The rated voltage of these batteries is approximately 3.6V, compared to 1.5V for most other types of batteries (Ni-Cd, Ni-MH, etc.). The volumetric and mass energy densities are approximately 300–500 Wh / l and 160–200 Wh / kg, respectively. These values ​​are the highest among all batteries currently on the market. Furthermore, these batteries feature low self-discharge and a long lifespan (500 or 1,000 cycles). Despite achieving such remarkable performance, all current lithium-ion batteries are leveling off in terms of performance, and prospects for improvement are considered limited.

[0008] Accordingly, lithium-sulfur (Li-S) batteries are gaining attention and emerging as an alternative to known lithium-ion batteries.

[0009] Like conventional lithium-ion rechargeable batteries, lithium-sulfur batteries operate through the movement of lithium ions within an electrolyte interposed between the anode and cathode. However, because lithium-sulfur batteries utilize only simple sulfur, they operate based on oxidation and reduction reactions between sulfur and lithium ions, unlike the reactions in conventional lithium-ion rechargeable batteries where lithium ions interlock between molecules of the electrode active material to modify the electrode structure and store energy. Consequently, lithium-sulfur batteries are not limited by electrode structures compared to conventional lithium-ion rechargeable batteries and can theoretically possess a larger capacity within the same volume. Due to these characteristics, in a lithium-sulfur battery composed of sulfur as the positive electrode and lithium metal as the negative electrode, assuming that the cyclic monomer sulfur (S8) reacts completely with lithium polysulfide (Li2S), the theoretical capacity is 1,675 mAh / g and the theoretical energy density is 2,600 Wh / kg, which is 3 to 6 times higher than other previously studied battery systems (Ni / MH battery: 450 Wh / kg, Li / FeS: 480 Wh / kg, Li / MnO2: 1,000 Wh / kg, Na / S: 800 Wh / kg).

[0010] Meanwhile, conventional transition metal oxide-based lithium-ion batteries can be evaluated as containing heavy metal pollutants because they utilize oxides of nickel (Ni), cobalt (Co), and manganese (Mn) in the cathode, which have densities higher than those of heavy metals (metals with a density of 5 g / mL or higher). However, lithium-sulfur batteries are considered eco-friendly as they exclude these pollutants and use non-toxic materials. Furthermore, sulfur, used as the cathode material, is an abundant resource, offering the advantage of being inexpensive.

[0011] Meanwhile, in a lithium-sulfur battery, the reduction reaction of sulfur and the oxidation reaction of lithium metal occur during discharge, and at this time, sulfur forms a linear structure of lithium polysulfide (LiPS) from the cyclic structure of S8. Such lithium-sulfur batteries are characterized by exhibiting stepwise discharge voltages until the lithium polysulfide is completely reduced to Li2S. However, the charge / discharge efficiency of the lithium-sulfur battery decreases during the charge / discharge process, and the battery life deteriorates. The causes of such degradation of the lithium-sulfur battery life are diverse, including side reactions of the electrolyte, instability of the lithium metal, and deposition of cathode byproducts (e.g., leaching of lithium polysulfide from the cathode).

[0012] In other words, in lithium-sulfur batteries that use sulfur-based compounds as the positive electrode active material and alkali metals such as lithium as the negative electrode active material, the leaching of lithium polysulfides occurs during charging and discharging. As lithium polysulfides leached from the positive electrode are transferred to the negative electrode, the capacity of the lithium-sulfur battery decreases, leading to a reduction in battery lifespan. Specifically, because lithium polysulfides leached from the positive electrode have high solubility in the electrolyte, they can pass through the separator via the electrolyte and migrate unintendedly toward the negative electrode. Consequently, the battery lifespan is reduced due to capacity loss caused by irreversible loss of the positive electrode active material and the deposition of sulfur particles on the lithium metal surface resulting from side reactions.

[0013] In order to solve the problem of reduced lifespan caused by lithium polysulfides, conventional research in the industry has been conducted, such as adding reaction-reducing materials to the cathode to prevent side reactions from proceeding on the lithium metal surface, but has not yielded significant results. The problem to be solved

[0015] According to one aspect of the present invention, the problem to be solved is to provide a cross-linked polythiophene compound capable of capturing lithium polysulfide eluted from the anode to improve the lifespan of a lithium-sulfur battery.

[0016] According to another aspect of the present invention, the problem to be solved is to provide a sulfur-carbon composite capable of capturing lithium polysulfide leached from the anode to improve the lifespan of a lithium-sulfur battery.

[0017] According to another aspect of the present invention, the problem to be solved is to provide a lithium-sulfur battery comprising the sulfur-carbon composite.

[0018] According to another aspect of the present invention, the problem to be solved is to provide a method for manufacturing the sulfur-carbon composite. means of solving the problem

[0020] To solve the problem of the present invention, the following embodiments provide a cross-linked polythiophene compound, a sulfur-carbon composite, a lithium-sulfur battery, and a method for manufacturing the sulfur-carbon composite.

[0021] According to the first embodiment,

[0022] A cross-linked polythiophene compound having a cross-linked structure and containing a cationic functional group is provided.

[0023] According to the second embodiment, in the first embodiment,

[0024] The above cationic functional group may include nitrogen cations, oxygen cations, sulfur cations, or two or more of these.

[0025] According to the third embodiment, in the second embodiment,

[0026] The above cationic functional group may be a quaternary ammonium functional group.

[0027] According to the fourth embodiment, in the third embodiment,

[0028] It may include a dialkyl amine group having the above-mentioned quaternary ammonium functional group.

[0029] According to the fifth embodiment, in the first embodiment,

[0030] A halogen anion may be further included as a counterion for the cation included in the above cationic functional group.

[0031] According to the 6th embodiment, in the 1st embodiment,

[0032] The above-mentioned cross-linked polythiophene compound can be represented by the following chemical formula 1.

[0034] [Chemical Formula 1]

[0035]

[0036] In the above chemical formula 1, R 1 , R 3 , R 5 , R 7 and R 9 Each is independently a simple linker, an alkylene group having 1 to 10 carbon atoms, a cycloalkylene group having 3 to 10 carbon atoms, or an arylene group having 6 to 20 carbon atoms, and R 2 and R 6 Each is independently a simple linker, an alkylene group having 1 to 10 carbon atoms, a cycloalkylene group having 3 to 10 carbon atoms, an arylene group having 6 to 20 carbon atoms, or a -COO- group, and R 4 and R 8 is a divalent cationic linker, A is F, Cl, Br, or I, and n and m are each independently 1 to 1,000,000.

[0037] According to the seventh embodiment, in the sixth embodiment,

[0038] The above divalent cationic linker is -NR 10 R 11 and R 10 and R 11Each can independently be hydrogen, an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms.

[0039] According to the eighth embodiment, in the sixth embodiment,

[0040] The above cross-linked polythiophene compound can be represented by the following chemical formula 2.

[0042] [Chemical Formula 2]

[0043]

[0044] In the above chemical formula 2, n and m are each independently 1 to 1,000,000.

[0045] According to the ninth embodiment,

[0046] porous carbon material;

[0047] A coating layer located on at least one surface of the above-mentioned porous carbon material and comprising a cross-linked polythiophene compound according to any one of the first to eighth embodiments; and

[0048] A sulfur-carbon composite is provided, comprising a sulfur compound located on the surface or within the pores of the porous carbon material, or on at least a portion of the surface of the coating layer.

[0049] According to the 10th embodiment, in the 9th embodiment,

[0050] The weight ratio of the porous carbon material and the cross-linked polythiophene compound may be 99:1 to 85:15.

[0051] According to the 11th embodiment, in the 9th embodiment,

[0052] The weight ratio of the porous carbon material coated with the coating layer and the sulfur compound may be 3:7 to 4:6.

[0053] According to the 12th embodiment,

[0054] It includes an anode, a cathode, and a separator interposed between the anode and the cathode, and

[0055] A lithium-sulfur battery is provided, characterized in that the anode comprises a sulfur-carbon composite according to any one of the ninth to eleventh embodiments.

[0056] According to the 13th embodiment,

[0057] A step of injecting a polythiophene compound into a solution in which a porous carbon material is dispersed, and coating the polythiophene compound onto at least one surface of the porous carbon material;

[0058] A step of crosslinking the polythiophene compound coated on the porous carbon material to form a crosslinked polythiophene compound; and

[0059] A method for manufacturing a sulfur-carbon composite according to any one of the 9th to 11th embodiments is provided, comprising the step of supporting a sulfur compound on the porous carbon material coated with the cross-linked polythiophene compound.

[0060] According to the 14th embodiment, in the 13th embodiment,

[0061] The above cross-linked polythiophene compound can be formed by injecting a cross-linking agent into the porous carbon material coated with the above polythiophene compound and heat treating it.

[0062] According to the 15th embodiment, in the 14th embodiment,

[0063] The above crosslinking agent may include a dihalogenated alkane compound.

[0064] According to the 16th embodiment, in the 13th embodiment,

[0065] The above polythiophene compound can be represented by the following chemical formula 3.

[0067] [Chemical Formula 3]

[0068]

[0069] In the above chemical formula 3, R1 and R 3 Each is independently a simple linker, an alkylene group having 1 to 10 carbon atoms, a cycloalkylene group having 3 to 10 carbon atoms, or an arylene group having 6 to 20 carbon atoms, and R 2 is a simple linker, an alkylene group having 1 to 10 carbon atoms, a cycloalkylene group having 3 to 10 carbon atoms, an arylene group having 6 to 20 carbon atoms, or a -COO- group, and R 12 is -NR 10 R 11 and R 10 and R 11 Each is independently hydrogen, an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms, and n is 1 to 1,000,000.

[0070] According to the 17th embodiment, in the 16th embodiment,

[0071] The method for preparing the above polythiophene compound is,

[0072] A step of preparing a thiophene monomer having a thiophene group and a cationic functional group;

[0073] A step of injecting the thiophene monomer into a solution in which the porous carbon material is dispersed; and

[0074] It may include a step of polymerizing the above thiophene monomer.

[0075] According to the 18th embodiment, in the 17th embodiment,

[0076] The above thiophene monomer can be polymerized in-situ on the surface of the porous carbon material.

[0077] According to the 19th embodiment, in the 17th embodiment,

[0078] The step of manufacturing the above thiophene monomer is,

[0079] Step of preparing a thiophene compound having an anionic functional group;

[0080] A step of reacting the above thiophene compound with a chloride; and

[0081] The method may include the step of reacting the thiophene compound that has reacted with the chloride with the alcohol compound having the cationic functional group to produce the thiophene monomer.

[0082] According to the 20th embodiment,

[0083] A step of crosslinking a polythiophene compound to form a crosslinked polythiophene compound;

[0084] A step of supporting a sulfur compound on a porous carbon material; and

[0085] A method for manufacturing a sulfur-carbon composite according to any one of the ninth to eleventh embodiments is provided, comprising the step of coating the cross-linked polythiophene compound on at least one surface of the porous carbon material supported with the sulfur compound. Effects of the invention

[0087] The sulfur-carbon composite of the present invention comprises a cross-linked polythiophene compound, wherein the cross-linked polythiophene compound has a cationic functional group. As the cross-linked polythiophene compound having a cationic functional group is coated onto the sulfur-carbon composite, the leaching of lithium polysulfide from the cathode of the lithium-sulfur battery is suppressed by the cationic functional group, and the volume expansion phenomenon of the cathode during charging and discharging of the battery can be reduced by the cross-linked structure of the cross-linked polythiophene compound. Accordingly, since the deposition of sulfur particles on the lithium metal surface of the negative electrode is prevented, the charge / discharge capacity of the lithium-sulfur battery is maintained, and the battery life can be improved. Brief explanation of the drawing

[0089] The following drawings attached to this specification illustrate preferred embodiments of the present invention and serve to further enhance understanding of the technical concept of the present invention together with the detailed description of the invention provided below; therefore, the present invention should not be interpreted as being limited only to the matters described in such drawings. Figures 1 and 2 are drawings for explaining a method for manufacturing a sulfur-carbon composite according to Example 1. Figure 3 is a graph showing the TGA analysis results for the sulfur-carbon composite of Example 1. Figure 4 is a graph showing the XRD analysis results for the sulfur-carbon composites of Example 1 and Comparative Example 1. Figure 5 is a graph showing the FT-IR analysis results for the sulfur-carbon composites of Example 1 and Comparative Example 1. Figure 6 is a graph showing the TEM analysis results for the sulfur-carbon composites of Example 1 and Comparative Example 1. Figure 7 is a graph showing the SEM analysis results for the sulfur-carbon composites of Example 1 and Comparative Example 1. FIGS. 8 to 10 are graphs showing the discharge capacity of a lithium-sulfur battery according to Example 1 and Comparative Example 1 after performing charge and discharge at 25°C. FIG. 11 is a graph evaluating the discharge capacity of lithium-sulfur batteries according to Comparative Example 1 and Examples 2 to 4 by performing charge and discharge at 25°C. FIG. 12 is a graph evaluating the discharge capacity of a lithium-sulfur battery according to Example 5 and Comparative Example 1 by performing charge and discharge at 25°C. FIG. 13 is a Nyquist plot showing the resistance before and after cell testing for lithium-sulfur batteries according to Example 1 and Comparative Example 1. Specific details for implementing the invention

[0090] The present invention will be described in more detail below.

[0092] Terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted in a meaning and concept consistent with the technical spirit of the invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0094] Throughout this specification, when a part is described as "comprising" or "having" a certain component, unless specifically stated otherwise, this means that it does not exclude other components but may include additional components.

[0096] The present invention relates to a cross-linked polythiophene compound, a sulfur-carbon composite comprising the cross-linked polythiophene compound, a lithium-sulfur battery comprising the sulfur-carbon composite, a method for manufacturing the sulfur-carbon composite, an electrochemical cell comprising the same, and a method for manufacturing the same.

[0097] In the present invention, the electrochemical cell may include any battery that performs an electrochemical reaction. Specific examples include all types of primary batteries, secondary batteries, fuel cells, solar cells, or capacitors such as supercapacitor elements. In particular, the electrochemical cell may be a secondary battery, and the secondary battery may be a lithium-ion secondary battery. Examples of the lithium-ion secondary battery include lithium-metal batteries, lithium-sulfur batteries, all-solid-state batteries, lithium-polymer batteries, etc., and among these, it is preferable that it be a lithium-sulfur battery.

[0099] Lithium-sulfur batteries are gaining attention as next-generation rechargeable batteries due to their advantages, including high discharge capacity and theoretical energy density among various rechargeable batteries, the ability to lower manufacturing costs as sulfur, used as the cathode active material, is abundant and inexpensive, and their eco-friendliness.

[0101] In the present invention, the positive electrode active material comprises a carbon-sulfur composite, wherein the carbon-sulfur composite comprises a porous carbon material. Since sulfur, which is the positive electrode active material in a lithium-sulfur battery, is an insulator, a sulfur-carbon composite formed by combining it with a carbon material, which is a conductive material, is generally used to compensate for its low electrical conductivity.

[0103] According to one aspect of the present invention,

[0104] A cross-linked polythiophene compound having a cross-linked structure and containing a cationic functional group is provided.

[0106] According to one embodiment of the present invention, the cationic functional group may include various cationic functional groups that enable the cross-linked polythiophene compound to be conductive. In one embodiment, the cationic functional group may include a nitrogen cation, an oxygen cation, a sulfur cation, or two or more of these. For example, the cationic functional group may include a nitrogen cation. Specifically, the cationic functional group may be a quaternary ammonium functional group, and the cross-linked polythiophene compound may include a dialkyl amine group having the quaternary ammonium functional group. In particular, when the cationic functional group is a quaternary ammonium, there is an advantage that the adsorption of lithium polysulfide is easier compared to functional groups such as ethylene glycol that facilitate the movement of lithium.

[0107] In addition, according to one embodiment of the present invention, the cross-linked polythiophene compound may have improved stiffness by having a cross-linked structure. Generally, when a battery is charged or discharged, problems of excessive volume expansion or swelling occur, but the compound of the present invention can have high stiffness, so it is possible to create a material that is resistant to volume expansion or swelling.

[0109] According to one embodiment of the present invention, the crosslinked polythiophene compound may further comprise a counterion for a cation included in the cationic functional group, for example, the counterion is a halogen anion (e.g., F- , Cl - , Br - , I - ) It may be. In one embodiment of the present invention, the counterion may be derived from a crosslinking agent for crosslinking the crosslinked polythiophene compound.

[0111] According to one embodiment of the present invention, the cross-linked polythiophene compound may be represented by the following chemical formula 1.

[0113] [Chemical Formula 1]

[0114]

[0115] In the above chemical formula 1, R 1 , R 3 , R 5 , R 7 and R 9 Each is independently a simple linker, an alkylene group having 1 to 10 carbon atoms, a cycloalkylene group having 3 to 10 carbon atoms, or an arylene group having 6 to 20 carbon atoms, and R 2 and R 6 Each is independently a simple linker, an alkylene group having 1 to 10 carbon atoms, a cycloalkylene group having 3 to 10 carbon atoms, an arylene group having 6 to 20 carbon atoms, or a -COO- group, and R 4 and R 8 is a divalent cationic linker, A is a halogen element (F, Cl, Br, I, etc.), and n and m can each independently be 1 to 1,000,000.

[0117] According to one embodiment of the present invention, the divalent cationic linker is -NR 10 R 11 and R 10 and R 11 Each can independently be hydrogen, an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms.

[0119] According to one embodiment of the present invention, R 1, R 3 , R 5 , R 7 and R 9 By controlling the bond length, the polarity of the cross-linked polythiophene compound can be controlled, and accordingly, the crystallinity and thermal properties of the cross-linked polythiophene compound can be controlled.

[0121] According to one embodiment of the present invention, the cross-linked polythiophene compound may be represented by the following chemical formula 2.

[0123] [Chemical Formula 2]

[0124]

[0125] In the above chemical formula 2, n and m can each independently be 1 to 1,000,000.

[0127] According to another aspect of the present invention,

[0128] porous carbon material;

[0129] A coating layer located on at least one surface of the above-described porous carbon material and comprising the above-described crosslinked polythiophene compound; and

[0130] A sulfur-carbon composite is provided, comprising a sulfur compound located on the surface or within the pores of the porous carbon material, or on at least a portion of the surface of the coating layer.

[0132] According to one embodiment of the present invention, the weight ratio of the porous carbon material and the cross-linked polythiophene compound may be 99:1 to 85:15, or 99:1 to 90:10.

[0134] The above porous carbon material includes a plate-shaped carbon material, and the specific surface area of ​​the porous carbon material is 1,000 m² 2 / g or more, and the pore volume of the porous carbon material is 4 cm³ 3 It can be more than / g.

[0135] The porous carbon material may have a high specific surface area to increase the number of active sites where sulfur can participate in oxidation / reduction reactions. Additionally, the porous carbon material may have a large pore volume to facilitate sulfur loading and to be advantageous for securing ion diffusion paths.

[0136] The above sulfur-carbon composite includes a porous carbon material as a support for supporting a sulfur-containing compound. Specifically, the above sulfur-carbon composite may include a plate-shaped porous carbon material as the porous carbon material. The plate-shaped porous carbon material may include, for example, graphene, graphene oxide, reduced graphene oxide (rGO), or a mixture of two or more of these.

[0137] In one embodiment of the present invention, the plate-shaped porous carbon material may comprise reduced graphene oxide alone.

[0138] The above porous carbon material is 1,000 m 2 It can have a specific surface area of ​​ / g or greater. Specifically, the BET specific surface area of ​​the porous carbon material is not specifically limited to an upper limit, but for example, 1,000 m² 2 / g or more than 1,500 m 2 / g or less, 1,300 m 2 / g or less, 1,200 m 2 / g or less, 1,100 m 2 / g or less, 1,050 m 2 It may be less than / g. A sulfur-carbon composite according to one embodiment of the present invention may have the advantage of a very large specific surface area because it includes a plurality of micropores on the outer surface and / or inside.

[0139] The above BET specific surface area is measured by the BET method and may represent a value measured according to a known method for measuring the BET specific surface area. For example, the above BET specific surface area may be a value calculated from the amount of nitrogen gas adsorbed at a liquid nitrogen temperature (77K) using BELSORP-max of BEL Japan.

[0140] The above porous carbon material is 4 cm 3 It can have a pore volume of 1 / g or more. Specifically, the pore volume of the porous carbon material is not specifically limited to an upper limit, but for example, 4 cm 3 / g or more 15 cm 3 / g or less, 6 cm 3 / g or more than 10 cm 3 / g or less, 6 cm 3 / g or more 8 cm 3 / g or less or 6.5 cm 3 / g or more 7.5 cm 3 It may be less than / g. The above pore volume may be a value calculated and measured, for example, through N2 isotherm analysis based on the adsorption of liquid nitrogen.

[0141] As described above, the porous carbon material in the sulfur-carbon composite according to one aspect of the present invention may include a plurality of micropores for supporting a sulfur-containing compound.

[0142] In one embodiment of the present invention, the porous carbon material may include a plurality of micropores on an outer surface and inside, wherein the micropores may include mesopores with a diameter of 1 nm or more and less than 50 nm and macropores with a diameter of 50 nm or more and 200 nm or less. In one embodiment of the present invention, the porous carbon material may have the mesopores and macropores evenly developed.

[0143] The diameter of the above micropores can be measured according to methods known in the art for measuring the diameter of pores of porous materials, and is not particularly limited to such measurement methods. For example, the average diameter of the above micropores may be measured using a scanning electron microscope (SEM), a field emission electron microscope (laser diffraction method), or a laser diffraction method. The measurement using the laser diffraction method may be performed using, for example, a commercially available laser diffraction particle size measuring device (e.g., Microtrac MT 3000).

[0144] In another embodiment of the present invention, the average diameter (D50) of the total pores of the porous carbon material may be, for example, 20 nm to 25 nm, but is not limited thereto. The average diameter (D50) refers to the diameter at the 50% point of the cumulative number distribution according to diameter.

[0145] In the present invention, at least a portion of the pore interior and exterior surfaces of the porous carbon material having the above-described characteristics includes a sulfur compound.

[0147] The above sulfur compound may be used without limitation as long as it can be used as a positive electrode active material in a lithium-sulfur secondary battery. For example, the above sulfur compound may be inorganic sulfur (S8), lithium polysulfide (Li2Sn, 1≤n≤8), carbon sulfur polymer (C2S x ) m It may include , 2.5≤x≤50, 2≤m) or a mixture thereof, but is not limited thereto.

[0148] In the above sulfur-carbon composite, the sulfur compound may be incorporated through physical adsorption with the porous carbon material, or through chemical bonding such as covalent bonding or van der Waals bonding between the sulfur element and carbon within the porous carbon material.

[0149] In one embodiment of the present invention, the porous carbon material and the sulfur compound in the sulfur-carbon composite may be included in a weight ratio of, for example, 1:9 to 9:1, and specifically, in a weight ratio of 1:9 to 5:5, 1:9 to 4:6, 1:9 to 3:7, or 1:9 to 1.5:8.5. When the weight ratio of the porous carbon material and the sulfur compound in the sulfur-carbon composite is within the ranges described above, including a high content of the sulfur compound may have an advantageous effect in terms of increasing the kinetic activity of the sulfur-carbon composite and improving conductivity through the porous carbon material, but the present invention is not limited thereto.

[0150] In another embodiment of the present invention, the content of the sulfur compound in the sulfur-carbon composite may be, for example, 10 wt% or more based on the total weight of the sulfur-carbon composite, specifically 50 wt% or more, 60 wt% or more, 70 wt% or more, 80 wt% or more, or 85 wt% or more. Additionally, within the above-described range, it may be 50 wt% to 90 wt% based on the total weight of the sulfur-carbon composite, specifically 60 wt% to 90 wt%, 70 wt% to 90 wt%, or 85 wt% to 90 wt%. When the content of the sulfur compound in the sulfur-carbon composite is within the above-described range, including a high content of the sulfur compound may have an advantageous effect in terms of increasing the kinetic activity of the sulfur-carbon composite and simultaneously improving conductivity through the porous carbon material, but the present invention is not limited thereto.

[0151] In one embodiment of the present invention, the average particle size (D50) of the sulfur-carbon composite may be, for example, 0.5 μm to 200 μm, 0.5 μm to 200 μm, 1 μm to 150 μm, or 10 μm to 150 μm. The particle size of the sulfur-carbon composite may be measured by scanning electron microscopy (SEM), field emission electron microscopy (laser diffraction method), or laser diffraction method. The measurement using the laser diffraction method may be, for example, by using a commercially available laser diffraction particle size measuring device (e.g., Microtrac MT 3000). The average particle size (D50) refers to the particle size at the 50% point of the cumulative number distribution according to particle size.

[0152] In one embodiment of the present invention, the sulfur-carbon composite has a Raman peak intensity ratio (I G / I D The ratio) may be 1 or less. For example, the above I G / I D When the ratio is 1 or less, the problem of reduced efficiency in complexation with sulfur-containing compounds or conversion reactions of lithium polysulfides due to excessively high crystallinity of the surface of the sulfur-carbon composite can be prevented.

[0153] The above Raman peak intensity ratio is I obtained from the spectrum of the carbon composite obtained through Raman spectroscopy. G and I D It can be measured through the value. In the obtained spectrum, I G represents the peak of the crystalline region (G-peak, 1573 / cm), and I D represents the peak of the amorphous region (D-peak, 1309 / cm). Therefore, in this case, I G / I D A smaller ratio value indicates lower crystallinity.

[0154] In one embodiment of the present invention, the sulfur-carbon composite may be formed by mixing the porous carbon material and a sulfur compound and then heat-treating, but the manufacturing method of the present invention is not limited thereto.

[0155] The sulfur-carbon composite of the present invention as described above includes a plate-shaped carbon material having a high specific surface area and a large pore volume, thereby not only increasing the loading amount of sulfur but also providing multiple active sites for the oxidation / reduction reaction of sulfur. Accordingly, it can play a role in improving battery efficiency and energy density when used as a cathode of a lithium-sulfur battery, but the mechanism of the present invention is not limited thereto.

[0157] In the sulfur-carbon composite of the present invention, the coating layer comprises the cross-linked polythiophene compound described above. For example, the weight ratio of the porous carbon material and the cross-linked polythiophene compound may be 99:1 to 85:15, or 99:1 to 90:10. Additionally, the weight ratio of the porous carbon material coated with the coating layer and the sulfur compound may be 3:7 to 4:6.

[0159] According to another aspect of the present invention,

[0160] A step of injecting a polythiophene compound into a solution in which a porous carbon material is dispersed, and coating the polythiophene compound onto at least one surface of the porous carbon material;

[0161] A step of crosslinking the polythiophene compound coated on the porous carbon material to form a crosslinked polythiophene compound; and

[0162] A method for manufacturing a sulfur-carbon composite is provided, comprising the step of supporting a sulfur compound on the porous carbon material coated with the cross-linked polythiophene compound.

[0164] According to another aspect of the present invention,

[0165] A step of crosslinking a polythiophene compound to form a crosslinked polythiophene compound;

[0166] A step of supporting a sulfur compound on a porous carbon material; and

[0167] A method for manufacturing a sulfur-carbon composite is provided, comprising the step of coating the cross-linked polythiophene compound on at least one surface of the porous carbon material supported with the sulfur compound.

[0169] The sulfur-carbon composite according to the present invention can be manufactured by the two manufacturing methods described above. For example, as in the former manufacturing method, the polythiophene compound can be polymerized in-situ in the porous carbon material to form the cross-linked polythiophene compound, and the sulfur compound can be supported on the porous carbon material coated with the cross-linked polythiophene compound.

[0170] Alternatively, as in the latter manufacturing method, the polythiophene compound may be polymerized ex-situ to form the cross-linked polythiophene compound, and the cross-linked polythiophene compound may be coated onto the porous carbon material supported with the sulfur compound.

[0172] According to one embodiment of the present invention, the crosslinked polythiophene compound can be formed by injecting a crosslinking agent into the porous carbon material coated with the polythiophene compound and heat treating it.

[0174] According to one embodiment of the present invention, the polythiophene compound may be represented by the following chemical formula 3.

[0176] [Chemical Formula 3]

[0177]

[0179] In the above chemical formula 3, R 1 and R 3 Each is independently a simple linker, an alkylene group having 1 to 10 carbon atoms, a cycloalkylene group having 3 to 10 carbon atoms, or an arylene group having 6 to 20 carbon atoms, and R 2is a simple linker, an alkylene group having 1 to 10 carbon atoms, a cycloalkylene group having 3 to 10 carbon atoms, an arylene group having 6 to 20 carbon atoms, or a -COO- group, and R 12 is -NR 10 R 11 and R 10 and R 11 Each is independently hydrogen, an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms, and n can be 1 to 1,000,000.

[0181] According to one embodiment of the present invention, a method for preparing the polythiophene compound comprises the step of preparing a thiophene monomer having a thiophene group and a cationic functional group;

[0182] A step of injecting the thiophene monomer into a solution in which the porous carbon material is dispersed; and

[0183] It may include a step of polymerizing the above thiophene monomer.

[0185] The step of manufacturing the above thiophene monomer is,

[0186] Step of preparing a thiophene compound having an anionic functional group;

[0187] A step of reacting the above thiophene compound with a chloride; and

[0188] The method may include the step of reacting the thiophene compound that has reacted with the chloride with the cationic alcohol compound to produce the thiophene monomer.

[0190] According to one embodiment of the present invention, the thiophene compound may be represented by the following chemical formula 4.

[0192] [Chemical Formula 4]

[0193]

[0194] In the above chemical formula 4, R 1The anionic functional group may be an anionic functional group, for example, the anionic functional group may include -COOH, -SO3H, -PhOH, -ArSO3H, or two or more of these.

[0196] According to one embodiment of the present invention, the chloride may be various chlorides including -Cl, and the R 1 If this is -COOH and the chloride is SOCl2, the thiophene compound reacted with the chloride may have the following chemical formula 5.

[0198] [Chemical Formula 5]

[0199]

[0201] According to one embodiment of the present invention, the thiophene compound (e.g., a compound represented by Formula 5) that has reacted with the chloride can be reacted with an alcohol compound having a cationic functional group to produce the thiophene monomer.

[0202] For example, the alcohol compound is 2-dimethylaminoethanol, and the thiophene monomer can be represented by the following chemical formula 6.

[0204] [Chemical Formula 6]

[0205]

[0206] As the cross-linked polythiophene compound having the above-mentioned cationic functional group is coated on the porous carbon material, lithium polysulfide eluted from the positive electrode of the lithium-sulfur battery may not be transferred to the negative electrode due to the cationic functional group. Therefore, since the deposition of sulfur particles on the lithium metal surface of the negative electrode is prevented, the charge / discharge capacity of the lithium-sulfur battery is maintained and the battery life can be improved.

[0208] A method for manufacturing a sulfur-carbon composite according to one embodiment of the present invention may be as follows.

[0209] First, as described above, a thiophene compound having an anionic functional group (e.g., -COOH) is prepared, and said thiophene compound is reacted with a chloride (e.g., SOCl2) in a solvent at a high temperature (e.g., 80°C to 100°C).

[0210] Here, the solvent is not particularly limited as long as it is a solvent capable of dissolving or dispersing the compound, and includes chlorine-based solvents such as chloroform, methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, chlorobenzene, o-dichlorobenzene; ether-based solvents such as tetrahydrofuran, dioxane; aromatic hydrocarbon-based solvents such as toluene, xylene, trimethylbenzene, mesitylene; aliphatic hydrocarbon-based solvents such as cyclohexane, methylcyclohexane, n-pentane, n-hexane, n-heptane, n-octane, n-nonane, n-decane; ketone-based solvents such as acetone, methyl ethyl ketone, cyclohexanone; ester-based solvents such as ethyl acetate, butyl acetate, ethyl cellosolve acetate; Polyhydric alcohols and their derivatives such as ethylene glycol, ethylene glycol monobutyl ether, ethylene glycol monoethyl ether, ethylene glycol monomethyl ether, dimethoxyethane, propylene glycol, diethoxymethane, triethylene glycol monoethyl ether, glycerin, 1,2-hexanediol, etc.; alcohol-based solvents such as methanol, ethanol, propanol, isopropanol, cyclohexanol, etc.; sulfoxide-based solvents such as dimethyl sulfoxide, etc.; and amide-based solvents such as N-methyl-2-pyrrolidone, N,N-dimethylformamide, etc.; benzoate-based solvents such as butyl benzoate, methyl-2-methoxybenzoate, etc.; tetralin; 3-phenoxy-toluene, etc. may be solvents.

[0211] The thiophene compound reacted with the chloride can be reacted with, for example, 2-dimethylaminoethanol and triethyleneamine (TEA) in a solvent to produce the thiophene monomer. Subsequently, the thiophene monomer is dissolved in a solvent and then injected into a solution in which a porous carbon material (e.g., Ketjen black (KB)) is dispersed together with a chloride (e.g., FeCl3), so that the thiophene monomer is polymerized in-situ on the surface of the porous carbon material to form the polythiophene compound.

[0212] A crosslinking agent may be injected into a solution in which the porous carbon material coated with the polythiophene compound is dispersed, and heat treatment may be performed to form the crosslinked polythiophene compound. For example, the crosslinking agent may be a dihalogenated alkane compound (e.g., 1,4-dibromobutane, 1,4-dichlorobutane, diiodobutane, dichlorobutane, and mixtures thereof), and as shown in FIG. 1, it may be diiodobutane.

[0214] Hereinafter, specific embodiments will be described in detail to aid in understanding the present invention. However, embodiments according to the present invention may be modified in various different forms, and the scope of the present invention should not be interpreted as being limited to the following embodiments. The embodiments of the present invention are provided to more completely explain the present invention to those with average knowledge in the art.

[0216] Example 1

[0217] Preparation of sulfur-carbon composites and anodes

[0218] A thiophene compound having an anionic functional group -COOH was prepared, and the thiophene compound was reacted with the chloride SOCl2 in a solvent at 90°C. Here, benzene was used as the solvent.

[0220] The thiophene compound reacted with the chloride was dissolved in a methylene chloride solvent, and then 2-dimethylaminoethanol and triethyleneamine (TEA) were injected to prepare the thiophene monomer. The thiophene monomer was dissolved in a chloroform solvent, injected into a porous carbon material (Ketjen black, KB) and a chloroform solvent containing dispersed FeCl3 chloride, and treated with ultrasound for 3 hours. Subsequently, the thiophene monomer was polymerized in-situ on the surface of the Ketjen black to form the polythiophene compound. (See Fig. 1)

[0222] Diiodobutane was injected as a crosslinking agent into a solution in which the porous carbon material coated with the polythiophene compound was dispersed, and the dialkyl amine group, which is a cationic functional group of the polythiophene compound, was activated by the crosslinking agent, and the polythiophene compounds were crosslinked with each other to form the crosslinked polythiophene compound.

[0224] As the positive electrode active material, a sulfur-carbon composite (CPTqD10-KB-S) prepared by supporting a sulfur compound on Ketjen black (CPTqD10-KB) coated with the aforementioned cross-linked polythiophene compound was used. The weight ratio of the Ketjen black to the cross-linked polythiophene compound was 90:10. The sulfur-carbon composite, polyacrylic acid (PAA) (weight-average molecular weight 450,000) as a binder, and Super P as a carbon conductive material were mixed in a weight ratio of 85:10:5. After adding 0.5 wt% of polyvinyl alcohol (PVA) (weight-average molecular weight 9,500) as a dispersant, a positive electrode slurry was prepared with a solid content concentration of 18 wt%. The positive electrode slurry was then uniformly coated onto an aluminum foil to a thickness of 400 µm and dried at 50°C to produce a positive electrode (see Fig. 2).

[0226] Manufacturing of lithium-sulfur batteries

[0227] A polyethylene porous film (Celgard separator) was used as the separator, lithium metal was used as the negative electrode, and 1.0 M LiNO3 was added to a mixed solvent having a volume ratio (v / v) of 1,3-dioxolane (DOL) and 1,2-dimethyl ether of 50:50 to prepare an electrolyte for a lithium-sulfur secondary battery.

[0229] An electrode assembly was manufactured by interposing a separator between the anode and cathode manufactured above, placing it in a coin cell case, and injecting a prepared electrolyte to manufacture a coin cell type lithium-sulfur battery.

[0231] Example 2

[0232] Preparation of sulfur-carbon composites and anodes

[0233] The sulfur compound was first supported on the Ketjen black, and the cross-linked polythiophene compound was coated on the Ketjen black supported with the sulfur compound. That is, the cross-linked polythiophene compound was prepared and coated by ex-situ polymerization of the polythiophene compound, and the weight ratio of the Ketjen black to the cross-linked polythiophene compound was 99:1.

[0235] Manufacturing of lithium-sulfur batteries

[0236] A lithium-sulfur battery was manufactured in the same manner as in Example 1, except that the anode prepared in Example 2 was used.

[0238] Example 3

[0239] Preparation of sulfur-carbon composites and anodes

[0240] A sulfur-carbon composite and an anode were prepared in the same manner as in Example 2, except that the weight ratio of the Ketjen black and the cross-linked polythiophene compound was 93:7.

[0242] Manufacturing of lithium-sulfur batteries

[0243] A lithium-sulfur battery was manufactured in the same manner as in Example 1, except that the anode prepared in Example 3 was used.

[0245] Example 4

[0246] Preparation of sulfur-carbon composites and anodes

[0247] A sulfur-carbon composite and an anode were prepared in the same manner as in Example 2, except that the weight ratio of the above Ketjen black and the above cross-linked polythiophene compound was 95:5.

[0249] Manufacturing of lithium-sulfur batteries

[0250] A lithium-sulfur battery was manufactured in the same manner as in Example 1, except that the anode prepared in Example 4 was used.

[0252] Example 5

[0253] Preparation of sulfur-carbon composites and anodes

[0254] A sulfur-carbon composite and an anode were prepared in the same manner as in Example 1, except that the weight ratio of the above Ketjen black and the above cross-linked polythiophene compound was 95:5.

[0256] Manufacturing of lithium-sulfur batteries

[0257] A lithium-sulfur battery was manufactured in the same manner as in Example 1, except that the anode prepared in Example 5 was used.

[0259] Comparative Example 1

[0260] Preparation of sulfur-carbon composites and anodes

[0261] A sulfur-carbon composite and a cathode were prepared in the same manner as in Example 1, except that a sulfur-carbon composite in which Ketjen black and a sulfur compound were mixed in a weight ratio of 3:7 was used as the cathode active material.

[0263] Manufacturing of lithium-sulfur batteries

[0264] A lithium-sulfur battery was manufactured in the same manner as in Example 1, except that the cathode prepared in Comparative Example 1 was used.

[0266] Analysis results

[0267] TGA analysis results

[0268] Figure 3 shows the TGA analysis results for the sulfur-carbon composite of Example 1. As a result of the TGA analysis, in the sulfur-carbon composite composed of Ketjen black coated with a cross-linked polythiophene compound and a sulfur compound, the content of the supported sulfur compound was measured to be 61 wt%.

[0270] XRD analysis results

[0271] Figure 4 shows the XRD analysis results for the sulfur-carbon composites of Example 1 and Comparative Example 1. As a result of the XRD analysis, a peak attributed to the cross-linked polythiophene compound of Example 1 was observed at 2θ=25±5.

[0273] FT-IR analysis results

[0274] Figure 5 shows the FT-IR analysis results for the sulfur-carbon composites of Example 1 and Comparative Example 1. As a result of the FT-IR analysis, characteristic peaks of the cross-linked polythiophene compound of Example 1 and the quaternary ammonium functional group contained therein were confirmed.

[0276] TEM analysis results

[0277] Figure 6 shows the TEM analysis results for the sulfur-carbon composites of Example 1 and Comparative Example 1. The TEM analysis results confirmed that the cross-linked polythiophene compound was coated on the Ketjen black of Example 1.

[0279] SEM analysis results (surface observation)

[0280] Figure 7 shows the SEM analysis results for the sulfur-carbon composites of Example 1 and Comparative Example 1. The SEM analysis confirmed that the cross-linked polythiophene compound was coated on the Ketjen black of Example 1.

[0282] Charge / Discharge Evaluation

[0283] FIG. 8 is a graph showing the discharge capacity evaluated by performing charge and discharge at 25°C under the following conditions for lithium-sulfur batteries according to Example 1 and Comparative Example 1.

[0285] Evaluation Equipment: WBSC3000 battery cycler (WonAtech)

[0286] Current density: 0.2 C-rate

[0288] Referring to FIG. 8, in the case of the lithium-sulfur battery according to Example 1, a higher discharge capacity was measured compared to the lithium-sulfur battery according to Comparative Example 1 during 1 to 120 cycles.

[0290] FIG. 9 is a graph showing the discharge capacity evaluated by performing charge and discharge at 25°C under the following conditions for lithium-sulfur batteries according to Example 1 and Comparative Example 1.

[0292] Evaluation Equipment: WBSC3000 battery cycler (WonAtech)

[0293] Current density: 0.5 C-rate

[0295] Referring to FIG. 9, in the case of the lithium-sulfur battery according to Example 1, a higher discharge capacity was measured compared to the lithium-sulfur battery according to Comparative Example 1 during 1 to 200 cycles.

[0297] FIG. 10 is a graph showing the discharge capacity evaluated by performing charge and discharge at 25°C under the following conditions for lithium-sulfur batteries according to Example 1 and Comparative Example 1.

[0299] Evaluation Equipment: WBSC3000 battery cycler (WonAtech)

[0300] Current density: 1 C-rate

[0302] Referring to FIG. 10, in the case of the lithium-sulfur battery according to Example 1, a higher discharge capacity was measured compared to the lithium-sulfur battery according to Comparative Example 1 for 40 to 160 cycles.

[0304] FIG. 11 is a graph showing the discharge capacity of lithium-sulfur batteries according to Comparative Example 1 and Examples 2 to 4, which were charged and discharged at 25°C under the following conditions.

[0306] Evaluation Equipment: WBSC3000 battery cycler (WonAtech)

[0307] Current density: 0.2 C-rate

[0309] Referring to FIG. 11, in the case of the lithium-sulfur batteries according to Examples 2 to 4, a higher discharge capacity was measured compared to the lithium-sulfur battery according to Comparative Example 1 during 1 to 70 cycles.

[0311] FIG. 12 is a graph showing the discharge capacity evaluated by performing charge and discharge at 25°C under the following conditions for lithium-sulfur batteries according to Example 5 and Comparative Example 1.

[0313] Evaluation Equipment: WBSC3000 battery cycler (WonAtech)

[0314] Current density: 0.2 C-rate

[0316] Referring to FIG. 12, in the case of the lithium-sulfur battery according to Example 5, a higher discharge capacity was measured compared to the lithium-sulfur battery according to Comparative Example 1 during 1 to 120 cycles.

[0318] Figure 13 shows the resistance of the lithium-sulfur batteries of Example 1 and Comparative Example 1 before and after a 200-cycle cell test at a 0.5 C-rate as a Nyquist plot. Referring to Figure 13, it was measured that the lithium-sulfur battery according to Example 1 had an improved resistance value compared to the lithium-sulfur battery according to Comparative Example 1 before and after the cell test.

Claims

Claim 1 A cross-linked polythiophene compound characterized by having a cross-linked structure, containing a cationic functional group, and represented by the following chemical formula 1. [Chemical Formula 1] In the above chemical formula 1, R 1 , R 3 , R 5 , R 7 and R 9 Each is independently a simple linker, an alkylene group having 1 to 10 carbon atoms, a cycloalkylene group having 3 to 10 carbon atoms, or an arylene group having 6 to 20 carbon atoms, and R 2 and R 6 Each is independently a simple linker, an alkylene group having 1 to 10 carbon atoms, a cycloalkylene group having 3 to 10 carbon atoms, an arylene group having 6 to 20 carbon atoms, or a -COO- group, and R 4 and R 8 is a divalent cationic linker, A is F, Cl, Br, or I, and n and m are each independently 1 to 1,000,000. Claim 2 delete Claim 3 delete Claim 4 delete Claim 5 delete Claim 6 delete Claim 7 In claim 1, the divalent cationic linker is -NR 10 R 11 and R 10 and R 11 A crosslinked polythiophene compound characterized in that each is independently hydrogen, an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms. Claim 8 A cross-linked polythiophene compound according to claim 1, characterized by being represented by the following chemical formula 2.[Chemical Formula 2] In the above chemical formula 2, n and m are each independently 1 to 1,000,000. Claim 9 A sulfur-carbon composite comprising: a porous carbon material; a coating layer located on at least one surface of the porous carbon material and comprising a crosslinked polythiophene compound according to any one of claims 1, 7 to 8; and a sulfur compound located on at least a portion of the surface or pores of the porous carbon material or on the surface of the coating layer. Claim 10 A sulfur-carbon composite according to claim 9, characterized in that the weight ratio of the porous carbon material and the cross-linked polythiophene compound is 99:1 to 85:

15. Claim 11 A sulfur-carbon composite according to claim 9, characterized in that the weight ratio of the porous carbon material coated with the coating layer and the sulfur compound is 3:7 to 4:

6. Claim 12 A lithium-sulfur battery comprising a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode, wherein the positive electrode comprises a sulfur-carbon composite according to claim 9. Claim 13 A method for manufacturing a sulfur-carbon composite according to claim 9, comprising: a step of injecting a polythiophene compound into a solution in which a porous carbon material is dispersed, thereby coating the polythiophene compound onto at least one surface of the porous carbon material; a step of crosslinking the polythiophene compound coated on the porous carbon material to form a crosslinked polythiophene compound; and a step of supporting a sulfur compound on the porous carbon material coated with the crosslinked polythiophene compound. Claim 14 A method for manufacturing a sulfur-carbon composite according to claim 13, wherein the crosslinked polythiophene compound is formed by injecting a crosslinking agent into the porous carbon material coated with the polythiophene compound and heat treating it. Claim 15 A method for preparing a sulfur-carbon composite according to claim 14, wherein the crosslinking agent comprises a dihalogenated alkane compound. Claim 16 A method for preparing a sulfur-carbon complex according to claim 13, characterized in that the polythiophene compound is represented by the following chemical formula 3. [Chemical Formula 3] In the above chemical formula 3, R 1 and R 3 Each is independently a simple linker, an alkylene group having 1 to 10 carbon atoms, a cycloalkylene group having 3 to 10 carbon atoms, or an arylene group having 6 to 20 carbon atoms, and R 2 is a simple linker, an alkylene group having 1 to 10 carbon atoms, a cycloalkylene group having 3 to 10 carbon atoms, an arylene group having 6 to 20 carbon atoms, or a -COO- group, and R 12 is -NR 10 R 11 and R 10 and R 11 Each is independently hydrogen, an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms, and n is 1 to 1,000,000. Claim 17 A method for manufacturing a sulfur-carbon composite according to claim 16, wherein the method for manufacturing the polythiophene compound comprises: a step of manufacturing a thiophene monomer having a thiophene group and a cationic functional group; a step of injecting the thiophene monomer into a solution in which the porous carbon material is dispersed; and a step of polymerizing the thiophene monomer. Claim 18 A method for manufacturing a sulfur-carbon composite according to claim 17, characterized in that the thiophene monomer is polymerized in-situ on the surface of the porous carbon material. Claim 19 A method for preparing a sulfur-carbon complex according to claim 17, wherein the step of preparing the thiophene monomer comprises: a step of preparing a thiophene compound having an anionic functional group; a step of reacting the thiophene compound with a chloride; and a step of reacting the thiophene compound reacted with the chloride with an alcohol compound having a cationic functional group to prepare the thiophene monomer. Claim 20 A method for manufacturing a sulfur-carbon composite according to claim 9, comprising the steps of: crosslinking a polythiophene compound to form a crosslinked polythiophene compound; supporting a sulfur compound on a porous carbon material; and coating the crosslinked polythiophene compound on at least one surface of the porous carbon material on which the sulfur compound is supported.

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