KR101794317B1 - Ladder structure carbon-tinoxide-sulfur composite, preparation method thereof and cathode material for lithium-sulfur battary comprising the same - Google Patents

Abstract

The present invention relates to a carbon-tin oxide-sulfur composite, a preparation method thereof and a positive electrode material for a lithium-sulfur battery. A ladder structure carbon-tin oxide-sulfur composite by a strong chemical bond is manufactured. By using the same, a lithium-sulfur battery inhibits elution of polysulfide and volume expansion of sulfur during charging and discharging, and has excellent lifespan properties and electrochemical performance due to smooth electron transfer.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ladder-type carbon-tin oxide-sulfur composite, a method for producing the same, and a cathode material for a lithium-

TECHNICAL FIELD The present invention relates to a carbon-tin oxide-sulfur composite having a ladder structure, a method for producing the same, and a cathode material for a lithium-sulfur battery including the same. More particularly, the present invention relates to a carbon- The present invention relates to a technique for application as a cathode material for a lithium-sulfur battery having excellent electrochemical performance using the same.

With the recent expansion of the electric vehicle market, the initiative of the secondary battery market has shifted from small batteries for IT to medium and large batteries, and the emergence of batteries with high energy density is continuously required, and costly and environmentally friendly batteries are demanded. Particularly, in order to realize a high energy density, development of an electrode active material having a large theoretical capacity is essential.

Lithium-sulfur batteries have a theoretical capacity (1,675 mAh / g) and an energy density (2,600 Wh / kg) that are eight times higher than conventional lithium-ion batteries. In addition, sulfur, which is used as a cathode active material, And is a next-generation high-density battery material as a high-density energy storage medium. Such a lithium-sulfur battery is a secondary battery using a sulfur-based compound having a sulfur-sulfur bond as a cathode active material and an alkali metal such as lithium as an anode active material. The reduction energy is stored and generated by the oxidation-reduction reaction in which sulfur-sulfur bonds are cut off during the reduction reaction, the oxidation number of sulfur is decreased, and oxidation-reduction sulfur is oxidized and sulfur-sulfur bonds are formed again .

However, sulfur has an electrical conductivity of 1 × 10 ^-16 S / m, which is close to non-conducting, and has difficulties in transferring electrons generated by electrochemical reactions. In addition, during actual cell operation, a chemical phenomenon occurs due to a chemical reaction between a sulfur anode and a liquid electrolyte. During the process, polysulfide dissolves into an electrolyte to cause active material loss. Depending on the type of electrolyte, polysulfide (Li ₂ S) and reacts with lithium to form a lithium sulfide (Li ₂ S), and is no longer able to participate in the cell reaction, thereby lowering the reversible capacity of the lithium-sulfur battery and deteriorating the life of the battery.

Therefore, in order to solve these problems, it is necessary to study a different direction in manufacturing a high-performance cathode active material and designing an electrode to suppress the elution of polysulfide. Specific examples of conventional patent technologies include a positive electrode for a lithium-sulfur battery including a carbon material having a large specific surface area (Patent Document 1), a positive electrode for a lithium-sulfur battery including a carbon nanotube conductive material coated with an amphipathic material A lithium-sulfur battery including a lithium-doped amorphous silicon oxide negative electrode (Patent Document 3), a lithium-sulfur battery positive electrode active material containing an Al ₂ O ₃ additive having a specific particle size (Patent Document 4) There is a lithium-sulfur battery positive electrode (Patent Document 5) using a wide porous graphene sheet, and a lithium-sulfur battery positive electrode including a hybrid composite of carbon nanotubes and sulfur coagulated in the form of a porous structure (Patent Document 6).

In general, carbon materials that can provide a smooth electrochemical reaction site of sulfur, which is not conductive, are used together. However, since carbon materials are nonpolar and can not efficiently hold polar polysulfide, a tendency to decrease capacity rapidly Show. Therefore, a metal oxide material is used which can form a strong chemical bond and capture the polysulfide. Recently, a hybrid structure including a conductive carbon material and a polar metal oxide has been reported. (Non-Patent Document 1) in which TiO ₂ is coated on carbon nanotubes (Non-Patent Document 1), and a cathode active material (Non-Patent Document 2) in which a hollow carbon nanofiber is filled with MnO ₂ nanosheet, .

Accordingly, the present inventors have completed the present invention by focusing on the fact that a carbon-tin oxide-sulfur composite having a ladder structure can be prepared and used as a cathode material for a lithium-sulfur battery having excellent electrochemical performance It came.

Patent Document 1. Korean Patent Publication No. 10-15591240000 Patent Document 2: Korean Patent Laid-Open Publication No. 10-2013-0146145 Patent Document 3: Korean Patent Laid-Open Publication No. 10-2015-0013087 Patent Document 4: Korean Patent Publication No. 10-05089200000 Patent Document 5: Korean Patent Publication No. 10-2014-0072485 Patent Document 6. Korean Patent Registration No. 10-14298420000

Non-Patent Document 1. Hwang et. al., Adv. Energy Mater. 6, 1501480 (2016) Non-Patent Document 2. Li et. al., Angew. Chem. Int. Ed. 54, 12886-12890 (2015)

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a carbon-tin oxide-sulfur composite having a ladder structure by strong chemical bonding and a method of manufacturing the same.

The second object of the present invention is to provide a carbon-tin-sulfur composite according to the present invention, which not only inhibits elution of polysulfide and volumetric expansion of sulfur during charging / discharging, And to provide a lithium-sulfur battery having chemical performance.

According to an aspect of the present invention, there is provided a carbon-tin oxide-sulfur composite including carbon nanotubes, tin oxide, and sulfur, wherein the tin oxide has a gap between the inner walls of the carbon nanotubes And wherein the cross bars of the tin oxide form a ladder shape arranged at intervals;

Wherein the sulfur is filled in a void space between the cross bars made of the tin oxide.

According to an embodiment of the present invention, the carbon nanotubes may be multi-wall carbon nanotubes.

According to another embodiment of the present invention, the particle size of the tin oxide may be 1 to 50 nm.

According to another embodiment of the present invention, the gap may be 5 to 50 nm.

(A) inserting tin oxide between the inner walls of the open carbon nanotubes to obtain a structure in the shape of a ladder with the tin oxide being spaced between the inner walls of the carbon nanotubes ; And (b) diffusing sulfur to the ladder-type structure. The present invention also relates to a method for producing a carbon-tin oxide-sulfur composite.

According to an embodiment of the present invention, the carbon nanotubes may be multi-wall carbon nanotubes.

According to another embodiment of the present invention, the step (a) may be performed by injecting a tin oxide precursor between the inner walls of the open carbon nanotubes and reducing the plasma to dry plasma.

Another aspect of the present invention relates to a cathode material for a lithium-sulfur battery comprising a carbon-tin oxide-sulfur composite according to the present invention.

Another aspect of the present invention relates to a lithium-sulfur battery including a cathode material for a lithium-sulfur battery according to the present invention.

Yet another aspect of the present invention is an electrical device comprising a cathode material for a lithium-sulfur battery according to the present invention, wherein the electrical device is one selected from an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, To an electric device.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a carbon-tin oxide-sulfur composite having a ladder structure by strong chemical bonding and a method for producing the same.

Further, by including the carbon-tin-sulfur complex according to the present invention, not only the dissolution of polysulfide and the volume expansion of sulfur at the time of charging / discharging are suppressed, but also lithium having a good life characteristic and electrochemical performance - A sulfur battery can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a carbon-tin oxide-sulfur composite prepared from Example 1 of the present invention. FIG.
2 is a graph showing a high resolution scan transmission electron microscope (HR-STEM) image and (b) EDX analysis results of the carbon-tin oxide-sulfur composite prepared in Example 1 of the present invention.
3 is a graph showing lifetime characteristics of a carbon-sulfur composite prepared from Comparative Example 1 of the present invention and a lithium-sulfur battery using the carbon-tin oxide-sulfur composite prepared from Example 1 as a cathode material.
FIG. 4 is a graph showing the results of (a) and (b) ultraviolet-visible spectra of the lithium-sulfur battery using the carbon-sulfur composite prepared in Comparative Example 1 of the present invention and the carbon-tin oxide- (C), and (d) energy dispersive X-ray spectroscopy (EDX) of a scanning electron microscope (SEM).
FIG. 5 is a graph showing the results of a real-time transmission scanning electron microscope (SEM) of a lithium-sulfur battery using the carbon-sulfur composite (a) prepared in Comparative Example 1 of the present invention and the carbon-tin oxide- It is an in-situ TEM image.

In the following, various aspects and various embodiments of the present invention will be described in more detail.

One aspect of the present invention is a carbon-tin oxide-sulfur composite including carbon nanotubes, tin oxide, and sulfur, wherein the tin oxide is positioned between the inner walls of the carbon nanotubes with an interval therebetween, ≪ / RTI > forming an array of spaced apart ladders; Wherein the sulfur is filled in a void space between the cross bars made of the tin oxide.

As a specific example, the longitudinal cross-section of the carbon-tin oxide-sulfur composite may be in the form of a ladder between the inner walls of the carbon nanotubes, with a cross bar made of the tin oxide arranged at predetermined intervals.

When the carbon-tin oxide-sulfur composite according to the present invention is applied to a cathode material for a lithium-sulfur battery, tin oxide (SnO 2) has a strong chemical bond ladder structure that supports the walls of carbon nanotubes, And the polysulfide is prevented from flowing out to the electrolyte during charging / discharging, thereby remarkably improving the lifetime of the battery.

According to an embodiment of the present invention, the carbon nanotube may be a single-walled carbon nanotube, a double-walled carbon nanotube, or a multi-walled carbon nanotube. Preferably, the multi-walled carbon nanotube may be a single-walled carbon nanotube or a double-walled carbon nanotube. Compared with the case of using a single-walled carbon nanotube or a double-walled carbon nanotube, It is effective.

The tin oxide may serve as an electrical conductor in the composite. That is, compared to the case where only the multi-walled carbon nanotubes are used, the electron transfer site can be increased and the reversible capacity and the rate characteristic of the cathode material can be improved.

According to another embodiment of the present invention, the particle size of the tin oxide may be 1 to 50 nm, preferably 5 to 20 nm, and when it is outside the preferred range, the carbon-tin oxide-sulfur It was confirmed that the composite did not have a ladder structure.

That is, if the size of the tin oxide particles is less than 5 nm, the contact area between the sulfur injected into the carbon nanotubes and the carbon nanotubes is widened and the role of the tin oxide which makes the trapezoidal structure becomes insignificant, , When the particle size is excessively larger than 20 nm, injection of sulfur into the carbon nanotube is limited and the amount of the active material is small, which makes it difficult to express a high capacity.

According to another embodiment of the present invention, the gap may be 5 to 50 nm, preferably 10 to 20 nm. It is possible to perform the function of a buffer layer which provides sufficient space for volume expansion of sulfur in the above preferred numerical range and it is confirmed that the effect of preventing the bulge expansion of sulfur is significantly reduced when the value is out of the preferred range.

(A) inserting tin oxide between the inner walls of the open carbon nanotubes to obtain a structure in the shape of a ladder with the tin oxide being spaced between the inner walls of the carbon nanotubes ; And (b) diffusing sulfur to the ladder-type structure. The present invention also relates to a method for producing a carbon-tin oxide-sulfur composite.

According to an embodiment of the present invention, the carbon nanotubes may be multi-wall carbon nanotubes.

According to another embodiment of the present invention, the step (a) may be performed by injecting a tin oxide precursor between the inner walls of the open carbon nanotubes and reducing the plasma to dry plasma. The dry plasma reduction method is a method capable of synthesizing a conductive oxide without using a toxic reducing agent at a temperature of 70 ° C or less and at atmospheric pressure, and can be synthesized uniformly and stably, and can be utilized in various technologies. Conventional wet plasma reduction method has inconvenience to remove ionic liquid and solvent after synthesis. Dry plasma reduction method has a merit that it can be synthesized relatively easily since solvent is not needed in synthesis. More specifically, the plasma not only has a property of etching, coating, or modifying the surface of the substrate, but also has a role of reducing ions. In the dry plasma reduction method, the metal ions are reduced on the support by using such a property of the plasma It is an economical, eco-friendly process that can be synthesized under conditions such as room temperature and atmospheric pressure, which is simple and does not cause environmental pollution.

The step (b) is a step of forming a carbon-tin oxide-sulfur composite by diffusing sulfur (S) in the ladder-like structure by heat treatment at 140 to 170 ° C, preferably 150 to 160 ° C through a melt infiltration method to be.

Another aspect of the present invention relates to a cathode material for a lithium-sulfur battery comprising a carbon-tin oxide-sulfur composite according to the present invention.

Another aspect of the present invention relates to a lithium-sulfur battery including a cathode material for a lithium-sulfur battery according to the present invention, including a cathode comprising a carbon-tin oxide-sulfur composite according to the present invention; A negative electrode comprising a negative active material selected from the group consisting of a material capable of reacting with lithium ions to reversibly form a lithium-containing compound, a lithium metal, and a lithium alloy; And a lithium-sulfur battery including an electrolyte.

As the cathode active material in the anode, sulfur (S), a sulfur-based compound, or a mixture thereof may be used.

The electrolytic solution may include electrolytic salts and organic solvents. As the organic solvent, a single organic solvent or two or more mixed organic solvents may be used. When two or more mixed organic solvents are used, it is preferable to select and use at least one solvent selected from the group consisting of a weak polar solvent group, a strong polar solvent group, a lithium metal protective solvent group, and two or more groups. A weak polar solvent is defined as a solvent having a dielectric constant of less than 15, which is capable of dissolving a sulfur element among aryl compounds, bicyclic ethers and acyclic carbonates, and the strong polar solvent is a bicyclic carbonate, a sulfoxide compound, a lactone compound , A ketone compound, an ester compound, a sulfate compound, and a sulfite compound, wherein the lithium protecting solvent is a saturated ether compound, an unsaturated ether compound, an N, O, S or a heterocyclic compound containing a combination thereof. The electrolyte may be a solvent having a charge / discharge cycle efficiency of 50% or more to form a stable SEI (Solid Electrolyte Interface) film on a lithium metal.

Yet another aspect of the present invention is an electrical device comprising a cathode material for a lithium-sulfur battery according to the present invention, wherein the electrical device is one selected from an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, To an electric device.

Hereinafter, production examples and embodiments according to the present invention will be described in detail with reference to the accompanying drawings.

Production Example 1: Preparation of multi-walled carbon nanotubes having open ends

The multi-walled carbon nanotubes (Hanwha Nanotech) having a diameter of 17-20 nm and a length of several tens of micrometers were annealed at 375 ° C for 30 minutes under an air atmosphere, and both ends were opened. Then, 30 ml of 37% hydrochloric acid Dispersed and ultrasonicated for 1 hour to remove catalyst impurities. Finally, the solution was washed several times with distilled water until the pH became neutral, and then dried overnight at 70 ° C to prepare a multi-walled carbon nanobut having open ends.

Preparation Example 2: Preparation of multi-walled carbon nanotubes containing tin oxide (SnO)

100 g of the multi-walled carbon nanotubes prepared in Preparation Example 1 was added to 20 mL of isopropanol containing 10 mM of SnCl ₄ .5H ₂ O and the mixture was subjected to ultrasound treatment for 2 hours , And isopropanol was evaporated in a vacuum oven at 70 ° C. to obtain a multiwalled carbon nanotube in which tin oxide (SnO 2) was encapsulated.

A dry plasma reduction process was performed in the reactor to align the tin oxide into the multi-walled carbon nanotubes. The plasma under atmospheric pressure was generated at a constant power of 160 W and an argon atmosphere at a rate of 5 L / min ^-1 . The substrate was moved at a rate of 5 mm / s and plasma treated at room temperature for 15 minutes to form a ladder- Walled carbon nanotubes were prepared.

Example 1: Preparation of carbon-tin oxide-sulfur complex

99.98% sulfur (Sigma Aldrich) was injected into the multi-walled carbon nanotubes containing tin oxide prepared in Preparation Example 2 through a melt infiltration method.

The multi-walled carbon nanotubes containing tin oxide and sulfur were mixed at a mass ratio of 1: 3. To remove excess sulfur outside the carbon nanotubes, a two-stage heat treatment was performed in an argon atmosphere at 155 DEG C for 8 hours and at 250 DEG C for 2 hours Respectively. Thereafter, the mixture was naturally cooled at room temperature to prepare a carbon-tin oxide-sulfur composite having a ladder-type structure containing tin oxide, in which sulfur was implanted, in the form of a multi-wall carbon nanotube.

Comparative Example 1: Preparation of carbon-sulfur complex

The procedure of Example 1 was repeated except that the multi-walled carbon nanotubes prepared in Preparation Example 1 were used instead of the multi-walled carbon nanotubes containing tin oxide prepared in Preparation Example 2, .

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a carbon-tin oxide-sulfur composite prepared from Example 1 of the present invention. FIG. First, a tin (Sn) precursor was prepared by the dry plasma reduction (DPR) process to form tin oxide (SnO) in a multiwalled carbon nanotube having both open ends. The multi - walled carbon nanotube composite containing the synthesized ladder - type tin oxide (SnO) was heat - treated at 155 ℃ through simple melt impregnation method to inject high - performance cathode active material for lithium - sulfur battery.

2 is a graph showing the results of (a) HR-STEM image and (b) energy dispersive X-ray spectroscopy (EDX) images of the (a) high resolution scan transmission electron microscope (HR-STEM) images of the carbon- Graph. FE-Tecnai F20 (Tecnai) operating at 200 kV was used for the analysis of high-resolution scanning transmission electron microscopy (HR-TEM). Element mapping analysis was performed at an acceleration voltage of 300 kV and an energy dispersive X-ray spectrometer The FEI Titan 80-300 transmission electron microscope was used. The content of sulfur in the compound was determined by using a thermogravimetric analyzer (TGA, Q600, TA Instrument) under a nitrogen atmosphere and a temperature range of 25-600 ° C at a scan rate of 10 ° C min ^-1 .

As shown in FIG. 2, tin oxide (SnO) nanoparticles having a size of 5-12 nm are injected into the multi-walled carbon nanotube. It can also be seen that the distance between the cross bars containing tin oxide (SnO) in the carbon-tin oxide-sulfur composite made in ladder form is 10-20 nm. The EDX analysis results show that the carbon, sulfur, tin, and oxygen elements appear at energy levels of 0.27, 2.32, 3.46, and 0.52 keV, respectively.

3 is a graph showing lifetime characteristics of a carbon-sulfur composite prepared from Comparative Example 1 of the present invention and a lithium-sulfur battery using the carbon-tin oxide-sulfur composite prepared from Example 1 as a cathode material. The electrochemical measurement was performed using a CR2032 coin battery manufactured in a dry room having a dew point temperature of -100.2 DEG C or less. The working electrode consisted of 70 wt% active material, 20 wt% conductive agent (Denka black 100) and 10 wt% poly (acrylic acid) binder and dispersed in ethanol using a small vibrating ball mill . The slurry thus formed was cast on an aluminum foil using a doctor blade and dried in a vacuum oven at 50 DEG C overnight. The density of the anode material drilled at a diameter of 12 mm was 5.5-6.2 mg · cm ^-2 and the average sulfur content was 1.0-1.3 mg · cm ^-2 . The electrolyte was prepared by dissolving 1, 3-dioxolane (DOL, 99.8%, Sigma Aldrich) and dimethoxymethane (DME, 99.5%, Sigma Aldrich) : 1.0 M bis (trifluoromethane) sulfonimide lithium salt (LiTFSI, 99.95%, Sigma Aldrich) was used as a solvent mixed in a volume ratio of 1: 1. Pure lithium metal foil (well course) and microporous polypropylene membrane (Celgard 2400) were used as counter electrode and separator, respectively. The constant current charge / discharge test was performed at room temperature using a cut-off potential of 1.7-2.8 V (vs. Li / Li +) The experiments were carried out at various current densities in a window using a battery experimental system (Maccor series-4000). The specific capacity was calculated based on the mass of sulfur.

The experimental conditions were measured at a current density of 1.7-2.8 V at the current density of 167.5 mA g ^-1 (0.1 C) for the first 5 cycles and then at a current density of 837.5 mA g ^-1 (0.5 C) .

3, the positive electrode of Example 1, which is a multi-walled carbon nanotube composite containing tin oxide (SnO) in the form of ladder with sulfur implanted, had an initial discharge capacity of 1682.4 mAh g < ^-1 & % Coulomb efficiency and a stable capacity of 530.1 mAh g ^-1 . On the other hand, the positive electrode of Comparative Example 1, which did not contain tin oxide (SnO), exhibited much faster capacity reduction and exhibited a coulombic efficiency of 99.9% after 1000 cycles and a discharge capacity of 349.3 mAh g ^-1 . Therefore, the positive electrode containing tin oxide (SnO) showed better reversibility and capacity retention characteristics. This excellent cycle characteristic is believed to be due to the fact that tin oxide (SnO) nanoparticles act as a sulfur immobilizer during the cycle, effectively preventing the dissolution of lithium polysulfide.

FIG. 4 is a graph showing the results of (a) and (b) ultraviolet-visible spectra of the lithium-sulfur battery using the carbon-sulfur composite prepared in Comparative Example 1 of the present invention and the carbon-tin oxide- (C), (d) scanning electron microscope (SEM).

After 1000 cycles of the lithium-sulfur battery using the cathode material of Comparative Example 1 and Example 1, the cell was disassembled, the electrode was shaken in the electrolyte, and the solution was subjected to ultraviolet-visible (UV-vis) analysis. Absorption spectra showed a distinct absorbance at 270-280 nm, due to the sulfur elements with long chains (S ₈ and S ₆ ^{2 -} ). In addition, the shoulder peaks at 310 nm and 334 nm are due to S ₆ ^{2 -} / S ₄ ^{2 -} and S ₃ ^{2 -} , respectively. These results indicate that sulfur and polysulfide have lower mobility at the anode containing tin oxide (SnO) than the anode containing no tin oxide (SnO) (see Figures 4 (a) and 4 (b) . In addition, SEM-EDX analysis of the two anodes to observe the distribution of sulfur present in the anode after 1000 cycles showed that the multi-walled carbon nanotube support as a non-polar material grabbed the polar polysulfide weakly, A multi-walled carbon nanotube support containing tin oxide as a material strongly retains the polysulfide due to dipole-dipole interactions between tin oxide (SnO) and the polysulfide. Therefore, the weaker sulfur peak of the anode containing tin oxide (SnO 2), which does not contain tin oxide (SnO 2) at 2.35 keV, is due to the diffusion of sulfur and polysulfide anions into tin oxide (SnO 2) nano It was confirmed that it was inhibited by the particles.

FIG. 5 is a graph showing the results of a real-time transmission scanning electron microscope (SEM) of a lithium-sulfur battery using the carbon-sulfur composite (a) prepared in Comparative Example 1 of the present invention and the carbon-tin oxide- It is an in-situ TEM image.

In FIG. 5, in order to clarify the role of tin oxide (SnO) nanoparticles aligned in multi-walled carbon nanotubes, a volumetric expansion of the cathode active material during the lithiation process was confirmed by real-time transmission electron microscopy (In-situ TEM) Respectively. Once the lithiation process begins with a 3 V DC voltage, the volume of the anode that does not contain tin oxide (SnO) is increasing over time (see FIG. 5 (a)). On the other hand, in the anode containing tin oxide (SnO), this volume expansion was not observed due to its strong nanostructure (see FIG. 5 (B)). It has been confirmed that tin oxide (SnO) aligned in the multi-walled carbon nanotube acts as a rigid support for preventing elution of sulfur, while suppressing volume expansion and increasing conductivity. This ladder-like structure contributes to the improved electrochemical performance of the positive electrode comprising tin oxide (SnO).

Therefore, according to the present invention, it is possible to provide a carbon-tin oxide-sulfur composite having a ladder-like structure by strong chemical bonding and a method for producing the same, and by using the same, the dissolution of polysulfide and the volume expansion of sulfur can be suppressed In addition, it can be applied to a lithium-sulfur battery having an excellent lifetime characteristic and electrochemical performance because electrons move smoothly.

Claims (10)

A carbon-tin oxide-sulfur composite comprising carbon nanotubes, tin oxides and sulfur,
Wherein the tin oxide is located between the inner walls of the carbon nanotubes at an interval and forms a ladder shape in which the cross bars made of the tin oxide are aligned at intervals;
Wherein the sulfur is filled in a void space between the cross bars made of the tin oxide. The method according to claim 1,
Wherein the carbon nanotubes are multi-walled carbon nanotubes. The method according to claim 1,
Wherein the tin oxide has a particle size of 1 to 50 nm. The method according to claim 1,
Lt; RTI ID = 0.0 > 50 < / RTI > nm. (a) inserting tin oxide between the inner walls of the carbon nanotubes having open ends, the tin oxides being spaced between the inner walls of the carbon nanotubes to obtain a ladder-like structure; And
(b) diffusing sulfur into the ladder-like structure. 6. The method of claim 5,
Wherein the carbon nanotubes are multi-walled carbon nanotubes. 6. The method of claim 5,
Wherein the step (a) is performed by injecting a tin oxide precursor between the inner walls of the opened carbon nanotubes and then reducing the carbon nanotubes to dry plasma. A positive electrode material for a lithium-sulfur battery comprising a carbon-tin oxide-sulfur composite according to any one of claims 1 to 4. 9. A lithium-sulfur battery including a cathode material for a lithium-sulfur battery according to claim 8. An electric device comprising a cathode material for a lithium-sulfur battery according to claim 8,
Wherein the electrical device is one selected from an electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, and a power storage device.

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