Electrolyte for lithium-sulfur batteries and lithium-sulfur batteries containing the same

Abstract

The present invention relates to an electrolyte for a lithium-sulfur battery and a lithium-sulfur battery including the same. The electrolyte for a lithium-sulfur battery includes a lithium salt and a non-aqueous solvent, and the non-aqueous solvent includes a glycol ether, a cyclic ether, and an acyclic ether represented by the following Chemical Formula 1: [Chemical formula 1] R 1 -OR 2 (In the above chemical formula 1, R 1 is unsubstituted or substituted C 1 ~C 3 R is an alkyl group of 2 is unsubstituted or substituted C 2 ~C 20 is an alkyl group of the formula:

Description

[Technical Field]

[0001] This invention relates to an electrolyte for lithium-sulfur batteries and a lithium-sulfur battery containing the same.

[0002] This application claims priority based on Korean Patent Application No. 2022-0110397 filed on 31 August 2022 and Korean Patent Application No. 2022-0157791 filed on 22 November 2022, and all content disclosed in the specifications and drawings of said applications is incorporated into this application. [Background technology]

[0003] A lithium-sulfur battery refers to a battery system that uses a sulfur-based substance with SS bonds (sulfur-sulfur bonds) as the positive electrode active material and lithium metal as the negative electrode active material. Sulfur, the main material of the positive electrode active material, is abundant worldwide, non-toxic, and has the advantage of having a low weight per atom.

[0004] As the application areas of secondary batteries expand to electric vehicles (EVs), energy storage systems (ESS), and other areas, lithium-sulfur battery technology, which can theoretically achieve a higher gravimetric energy density (~2,600 Wh / kg) compared to lithium-ion secondary batteries with a relatively lower gravimetric energy density (~250 Wh / kg), is attracting attention.

[0005] In a lithium-sulfur battery, during discharge, lithium, which is the negative electrode active material, releases electrons and is oxidized while being ionized into lithium cations. A sulfur-based substance, which is the positive electrode active material, is reduced while accepting electrons. Here, using the reduction reaction of the sulfur-based substance, the S-S bond accepts two electrons and is converted into the form of sulfur anions. The lithium cations generated by the oxidation reaction of lithium are transmitted to the positive electrode through the electrolyte, and this combines with the sulfur anions generated by the reduction reaction of the sulfur-based compound to form a salt. Specifically, sulfur before discharge has a cyclic S8 structure, which is converted into lithium polysulfide (LiSx) by the reduction reaction and is completely converted to generate lithium sulfide (Li2S).

[0006] At this time, in the sulfur-based compound that is the positive electrode active material, it is difficult to ensure reactivity with electrons and lithium ions in the solid phase due to the low electrical conductivity characteristics of sulfur. Therefore, in order to improve the reactivity of sulfur in a lithium-sulfur battery, an intermediate polysulfide in the form of Li2S x is generated to induce a liquid reaction and improve the reactivity. Such a technique uses an ether-based solvent such as dioxolane or dimethoxy ethane (DME), which has high solubility in lithium polysulfide, as the solvent of the electrolyte. As a result, the reactivity of sulfur and the battery life are affected according to the content of the electrolyte.

[0007] On the other hand, in recent years, efforts have been actively made in research and development on lithium-sulfur secondary batteries that can be driven at low temperatures, which are required for aircraft and next-generation electric vehicles. However, in a lithium-sulfur secondary battery, polysulfide (PS) elutes from the positive electrode, increasing the material resistance of the electrolyte. Therefore, at present, it is still difficult to drive at low temperatures.

[0008] In short, lithium-sulfur (Li-S) batteries are driven by a solid-to-liquid reaction during the first discharge (~2.3V), in which the active material dissolves from the positive electrode in the form of PS (polystyrene foam). During the second discharge (~2.1V), a liquid-to-solid reaction occurs, where the dissolved PS is repositioned at the positive electrode. Under this driving principle, the largest amount of PS is dissolved into the electrolyte at the end of the first discharge (State of Charge (SOC) = 70) when the solid-to-liquid reaction is completed, and this is when the largest overvoltage occurs in the lithium-sulfur battery. In particular, when driving with a small amount of electrolyte, the overvoltage is especially large at SOC 70, when the largest amount of PS is dissolved into the small amount of electrolyte, which presents a problem in driving lithium-sulfur batteries at low electrolyte concentrations.

[0009] Furthermore, when using ether-based solvents, which have been developed conventionally, as the electrolyte for lithium-sulfur batteries, the use of ether-based solvents with low boiling points (bp) can lead to gas generation inside the battery during low-temperature operation, posing a risk of explosion.

[0010] For this reason, there is a strong desire to develop lithium-sulfur batteries that not only control the elution characteristics of polysulfide from the positive electrode and thus control the material resistance of the electrolyte, but also ensure stability when operating the battery at low electrolyte concentrations and high energy densities. [Overview of the project] [Problems that the invention aims to solve]

[0011] Therefore, the problem that the present invention aims to solve is to provide an electrolyte for lithium-sulfur batteries that solves the above-mentioned problems and improves resistance characteristics by controlling the elution characteristics of polysulfide (PS) from the positive electrode.

[0012] In particular, an object thereof is to provide an electrolyte for a lithium-sulfur battery in which elution of polysulfide is suppressed from the initial discharge stage of the battery, an overvoltage phenomenon is improved, and electrolyte resistance characteristics are enhanced. Thereby, an object thereof is to provide a battery for a lithium-sulfur battery in which the problem of decreased reactivity is improved and output characteristics are enhanced.

[0013] Thereby, an object thereof is to provide a battery for a lithium-sulfur battery that can stably drive at a low electrolyte concentration and high energy.

Means for Solving the Problems

[0014] In order to solve the above problems, according to one aspect of the present invention, an electrolyte for a lithium-sulfur battery having the following aspects is provided.

[0015] The electrolyte for a lithium-sulfur battery according to the first aspect includes a lithium salt and a non-aqueous solvent, and the non-aqueous solvent includes a glycol ether, a cyclic ether, and an acyclic ether represented by the following Chemical Formula 1.

[0016] [Chemical Formula 1] R 1 -O-R 2 (In the above Chemical Formula 1, R 1 is an unsubstituted or substituted C1-C3 alkyl group, and R 2 is an unsubstituted or substituted C2-C 20 alkyl group.)

[0017] According to the second aspect, the R 1 is an unsubstituted or substituted C1-C2 alkyl group, and the R 2 is an unsubstituted C4-C 10 alkyl group, or a substituted C2-C 10 alkyl group, and may be the electrolyte for a lithium-sulfur battery according to the first aspect.

[0018] According to a third embodiment, the acyclic ether may be an electrolyte for a lithium-sulfur battery according to the first or second embodiment, comprising a fluorine-free acyclic ether.

[0019] According to the fourth embodiment, the acyclic ether may include a fluorine-free acyclic ether, and the fluorine-free acyclic ether may be an electrolyte for a lithium sulfur battery according to any one of the first to third embodiments, comprising methyl propyl ether, ethyl propyl ether, dipropyl ether, methyl butyl ether, methyl hexyl ether, ethyl butyl ether, ethyl hexyl ether, or a mixture of two or more of these.

[0020] According to the fifth aspect, the acyclic ether may be an electrolyte for a lithium-sulfur battery according to any one of the first to fourth aspects, comprising a fluorine-containing acyclic ether.

[0021] According to the sixth aspect, the acyclic ether includes a fluorine-containing acyclic ether, and the fluorine-containing acyclic ether may be an electrolyte for a lithium sulfur battery according to any one of the first to fifth aspects, comprising bis-(2,2,2-trifluoroethyl) ether.

[0022] According to the seventh aspect, the electrolyte for the lithium sulfur battery may be the electrolyte for the lithium sulfur battery according to any one of the first to sixth aspects, which does not contain 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether.

[0023] According to the eighth aspect, the glycol ether may be dimethoxyethane, diethoxyethane, ethylene glycol ethyl methyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol methyl ethyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, triethylene glycol methyl ethyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, tetraethylene glycol methyl ethyl ether, polyethylene glycol dimethyl ether, polyethylene glycol diethyl ether, polyethylene glycol methyl ethyl ether, or an electrolyte for a lithium sulfur battery according to any one of the first to seventh aspects, comprising two or more of these.

[0024] According to the ninth aspect, the cyclic ether may be furan, 2-methylfuran, 3-methylfuran, 2-ethylfuran, 2-propylfuran, 2-butylfuran, 2,3-dimethylfuran, 2,4-dimethylfuran, 2,5-dimethylfuran, pyran, 2-methylpyran, 3-methylpyran, 4-methylpyran, benzofuran, 2-(2-nitrovinyl)furan, thiophene, 2-methylthiophene, 2-ethylthiophene, 2-propylthiophene, 2-butylthiophene, 2,3-dimethylthiophene, 2,4-dimethylthiophene, 2,5-dimethylthiophene, or an electrolyte for a lithium sulfur battery according to any one of the first to eighth aspects, comprising two or more of these.

[0025] According to the tenth aspect, the lithium salt is LiCl, LiBr, LiI, LiClO4, LiBF4, LiB 10 Cl 10This could be an electrolyte for a lithium-sulfur battery according to any one of the first to ninth embodiments, comprising LiPF6, LiCF3SO3, LiCF3CO2, LiC4BO8, LiAsF6, LiSbF6, LiAlCl4, CH3SO3Li, CF3SO3Li, (CF3SO2)2NLi, (C2F5SO2)2NLi, (SO2F)2NLi, (CF3SO2)3Cli, lithium chloroborane, lithium lower aliphatic carboxylate, lithium 4-phenylborate, lithium imide, or two or more of these.

[0026] According to the eleventh embodiment, the acyclic ether may be an electrolyte for a lithium sulfur battery according to any one of the first to tenth embodiments, provided that it is included in a content of 20% by volume or less based on the total volume of the non-aqueous solvent.

[0027] According to the twelfth embodiment, the acyclic ether may be an electrolyte for a lithium sulfur battery according to any one of the first to eleventh embodiments, provided that it is included in a content of 5% by volume or less based on the total volume of the non-aqueous solvent.

[0028] According to the 13th embodiment, the electrolyte for a lithium sulfur battery may be one of the first to 12 embodiments, wherein, based on the total volume of the non-aqueous solvent, the content of the glycol ether is 65% by volume or more, the sum of the content of the cyclic ether and the acyclic ether is 35% by volume or less, and, based on the total volume of the non-aqueous solvent, the content of the acyclic ether is 20% by volume or less.

[0029] According to the 14th aspect, the electrolyte for a lithium-sulfur battery may further include a nitrate compound, a nitrite compound, or a mixture thereof, as described in any one of the first to 13 aspects.

[0030] According to another aspect of the present invention, lithium-sulfur batteries in the following embodiments are provided.

[0031] A lithium-sulfur battery according to the 15th embodiment includes a positive electrode containing a positive electrode active material and a negative electrode containing a negative electrode active material. According to the sixteenth aspect, the lithium sulfur battery may be the lithium sulfur battery according to the fifteenth aspect, wherein the ratio of the electrolyte to the positive electrode active material (El / S ratio) is 2.5 or less.

[0032] According to the 17th aspect, the positive electrode active material may be a lithium-sulfur battery according to the 15th or 16th aspect, comprising a sulfur element, a sulfur compound, or a mixture thereof.

[0033] According to the 18th aspect, the positive electrode active material is inorganic sulfur (S8), Li2Sn (n≧1), disulfide compound, organic sulfur compound, carbon-sulfur polymer ((C2S x ) n The lithium sulfur battery may be one of the 15th to 17th embodiments, wherein x is an integer between 2.5 and 50, and n ≥ 2, or a mixture of two or more of these.

[0034] According to the 19th aspect, the negative electrode active material may be a lithium-sulfur battery according to any one of the 15th to 18th aspects, comprising lithium metal, a lithium alloy, or a mixture thereof. [Effects of the Invention]

[0035] An electrolyte for lithium-sulfur batteries according to one aspect of the present invention has the effect of suppressing the elution of polysulfide (PS) from the positive electrode.

[0036] As a result, a lithium-sulfur battery according to one aspect of the present invention has the effect of preventing overvoltage at the initial discharge end (SOC70) during operation, improving responsiveness, and improving output characteristics.

[0037] In particular, the electrolyte for lithium-sulfur batteries according to one aspect of the present invention has the effect of suppressing the elution of PS from the positive electrode and enabling stable operation when operating at low electrolyte concentrations.

[0038] The following drawings accompanying this specification illustrate preferred embodiments of the present invention and are intended to further illustrate the technical idea of ​​the invention along with the content of the invention; therefore, the present invention shall not be construed as being limited only to what is shown in the drawings. [Brief explanation of the drawing]

[0039] [Figure 1] This graph shows the results of evaluating the discharge capacity of the batteries in Examples 1 to 3 and Comparative Example 1 described in this specification. [Figure 2] This graph shows the results of evaluating the life characteristics of the batteries in Examples 1 to 3 and Comparative Example 1 in this specification, according to the charge / discharge cycle. [Figure 3] This graph shows the results of evaluating the discharge capacity of the batteries in Examples 4 to 7 and Comparative Example 2 of this specification. [Figure 4] This graph shows the results of evaluating the life characteristics of the batteries in Examples 4 to 7 and Comparative Example 2 in this specification, according to the charge / discharge cycle. [Modes for carrying out the invention]

[0040] The present invention will be described in detail below. However, the present invention is not limited in any way to what is described below, and each component can be modified or selectively mixed as needed. Therefore, it should be understood that this includes all modifications, equivalents or substitutes that fall within the spirit and technical scope of the present invention.

[0041] In this specification, when a component is said to "include" another component, unless otherwise specified, this means that it may include other components, rather than excluding them.

[0042] In this specification, the term "polysulfide (PS)" is defined as "polysulfide ion (S) x 2-, x=8, 6, 4, 2)) and "Lithium polysulfide (Li2S x or LiS x - This concept encompasses all of the following: x = 8, 6, 4, 2).

[0043] In this specification, the term "low electrolyte" as used in relation to the operation of a lithium-sulfur battery under low electrolyte concentrations may, for example, refer to a state in which the ratio of electrolyte to sulfur (S) or El / S ratio in a lithium-sulfur battery is 2.5 ml / g or less. It will be obvious to those skilled in the art that the term "operation under low electrolyte concentrations" is used merely to explain that the electrolyte for lithium-sulfur batteries according to the present invention and the lithium-sulfur battery containing it can exhibit excellent properties even when operated under low electrolyte concentrations, and is not intended to limit the amount of the electrolyte for lithium-sulfur batteries or the driving electrolyte for lithium-sulfur batteries according to the present invention.

[0044] During the operation of a lithium-sulfur battery, polysulfide (PS, LiSx), formed by the reduction of sulfur (S8) from the positive electrode, is eluted as an electrolyte. However, electrolytes with a high ratio of solvent to polysulfide have the problem of inducing overvoltage due to the high concentration of polysulfide in the solvent. In contrast, electrolytes with a high ratio of non-solvent to polysulfide have the effect of suppressing the elution of polysulfide and preventing the overvoltage phenomenon described above. Accordingly, one aspect of the present invention, in the electrolyte for lithium-sulfur batteries, attempts to suppress the elution of polysulfide into the electrolyte by using a specific combination of non-solvent and polysulfide.

[0045] An electrolyte for a lithium-sulfur battery according to one aspect of the present invention comprises a lithium salt and a non-aqueous solvent, wherein the non-aqueous solvent includes glycol ethers, cyclic ethers, and acyclic ethers represented by the following chemical formula 1.

[0046] [Chemical formula 1] R 1 -OR 2 (In the above chemical formula 1, R 1 R is an unsubstituted or substituted C1-C3 alkyl group, 2 C2~C is either unsubstituted or substituted. 20 It is an alkyl group.

[0047] The lithium salt is included as an electrolyte salt in the electrolyte for the lithium-sulfur battery, and the non-aqueous solvent is included as a medium in the electrolyte for the lithium-sulfur battery.

[0048] According to the present invention, by using a combination of three ethers as the non-aqueous solvent—a glycol ether containing two oxygen atoms, a cyclic ether containing at least one oxygen atom (O) or sulfur atom (S) in its ring structure, and an acyclic ether represented by the above chemical formula 1—it is possible to provide an electrolyte that enables a lithium-sulfur battery to operate stably at a low electrolyte concentration; however, the mechanism of the present invention is not limited in any way to this.

[0049] If the electrolyte for lithium-sulfur batteries does not contain the acyclic ether as a non-aqueous solvent and contains only the glycol ether and cyclic ether, there is a problem in that an overvoltage occurs at SOC70 when the battery using this electrolyte is operated at a low electrolyte concentration. Therefore, according to one aspect of the present invention, the non-aqueous solvent contains the acyclic ether.

[0050] Specifically, the acyclic ether includes the compound represented by the above chemical formula 1.

[0051] With respect to the above chemical formula 1, in one embodiment of the present invention, the R 1Specifically, this may be an unsubstituted or substituted methyl group, an unsubstituted or substituted ethyl group, or an unsubstituted or substituted propyl group. In this case, the substituents included in the substituted methyl group, substituted ethyl group, or substituted propyl group are not limited to these, but may include, for example, a halogen atom, a hydroxyl group, a nitro group, a cyano group, an amino group, an amidino group, an acetamino group, a hydrazine, a hydrazizone, a carboxyl group, a sulfonyl group, a sulfamoyl group, a sulfonic acid group, a phosphoric acid group, or a combination thereof.

[0052] In another embodiment of the present invention, the R 1 Specifically, these may be an unsubstituted methyl group, an unsubstituted ethyl group, an unsubstituted propyl group, an ethyl group substituted with at least one halogen atom, or a propyl group substituted with at least one halogen atom.

[0053] In one embodiment of the present invention, the R 2 Specifically, this refers to C2-C with no substitution or substitution. 20 It can be an alkyl group, in which case the substitution C2~C 20 The substituents included in the alkyl group are not limited to these, but include, for example, halogen atoms, hydroxyl groups, nitro groups, cyano groups, amino groups, amidino groups, acetamino groups, hydrazine, hydrazizone, carboxyl groups, sulfonyl groups, sulfamoyl groups, sulfonic acid groups, phosphoric acid, C1-C5 alkyl groups, C1-C5 alkoxy groups, C2-C5 alkenyl groups, C2-C5 alkynyl groups, C4-C 10 Cycloalkyl groups, C6~C 10 The aryl group, C6~C 10 heteroaryl group, C6~C 20 Aryl alkyl groups, C6~C 20 It may be a heteroarylalkyl group, or a combination thereof.

[0054] In another embodiment of the present invention, the R 2These are not limited in any way, but for example, ethyl group, 2-fluoroethyl group, 1,2-difluoroethyl group, 1,1-difluoroethyl group, 2,2-difluoroether group, 2,2,2-trifluoroethyl group, n-propyl group, n-butyl group, n-amyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group, n-pentyl group. Tadecyl group, n-hexadecyl group, n-heptadecyl group, n-octadecyl group, n-nonadecyl group, n-eicosanyl group, iso-propyl group, sec-butyl group, iso-butyl group, tert-butyl group, 1-methylbutyl group, 1-ethylpropyl group, 2-methylbutyl group, iso-amyl group, neopentyl group, 1,2-dimethylpropyl group, 1,1-dimethylpropyl group, tert-amyl group, 1,3-dimethylbutyl group, 3,3-dimethylbutyl 2-ethylbutyl group, 2-ethyl-2-methylpropyl group, linear or branched heptyl group, 1-methylheptyl group, 2-ethylhexyl group, 1,5-dimethylhexyl group, tert-octyl group, branched nonyl group, branched decyl group, branched undecyl group, branched dodecyl group, branched tridecyl group, branched tetradecyl group, branched pentadecyl group, branched hexadecyl group, branched heptadecyl group, branched octadecyl group The group may be a linear or branched nonadecyl group, a linear or branched eicosanyl group, a cyclopropyl group, a cyclopropylmethyl group, a cyclobutyl group, a cyclobutylmethyl group, a cyclopentyl group, a cyclohexyl group, a cyclohexylmethyl group, a cycloheptyl group, a cyclooctyl group, a cyclohexylpropyl group, a cyclododecyl group, a norbornyl group, a bornyl group, a cyclopentylethyl group, a bicyclooctyl group, or a combination thereof.

[0055] In one embodiment of the present invention, the R 1 is an unsubstituted or substituted C1-C2 alkyl group, and the R 2 This is the unsubstituted C4~C 10 It can be an alkyl group.

[0056] In another embodiment of the present invention, the R 2 is an unsubstituted or substituted C1-C2 alkyl group, and the R 2 This is the substitution C2~C 10 It can be an alkyl group.

[0057] In one embodiment of the present invention, the acyclic ether may include a fluorine-free acyclic ether, a fluorine-containing acyclic ether, or a mixture thereof.

[0058] In this specification, the term "fluorine-free acyclic ether" means that in the chemical formula 1 of the above-mentioned acyclic ether, R 1 and R 2 This term collectively refers to compounds in which the alkyl group is either an unsubstituted alkyl group or, if it is a substituted alkyl group, an alkyl group that does not contain a fluorine atom (-F) as a substituent. Conversely, the "fluorine-containing acyclic ether" refers to a compound in which, in chemical formula 1 of the above-mentioned acyclic ether, R 1 and R 2 Compounds in which at least one of the alkyl groups is a substituted alkyl group, and in this case contain at least one fluorine atom (-F) as a substituent, are collectively referred to as such.

[0059] In one embodiment of the present invention, the acyclic ether may include a fluorine-free acyclic ether. In another embodiment of the present invention, the acyclic ether may consist solely of a fluorine-free acyclic ether.

[0060] The fluorine-free acyclic ethers may include, but are not limited to, methyl propyl ether, ethyl propyl ether, dipropyl ether, methyl butyl ether, methyl hexyl ether, ethyl butyl ether, ethyl hexyl ether, or mixtures of two or more of these.

[0061] In another embodiment of the present invention, the acyclic ether may include a fluorine-containing acyclic ether. In another embodiment of the present invention, the acyclic ether may consist solely of a fluorine-containing acyclic ether.

[0062] Examples of fluorine-containing acyclic ethers include bis-(2,2,2-trifluoroethyl) ether, but the present invention is not limited thereto.

[0063] In another embodiment of the present invention, the R 1 and R 2 These can be alkyl groups having different numbers of carbon atoms. For example, the R 1 is an unsubstituted or substituted C1-C2 alkyl group, and the R 2 C4~C is either unsubstituted or substituted. 10 It may be an alkyl group. The present invention is not limited thereto, however, the R 1 and R 2 When the elements have different numbers of carbon atoms, they may exhibit a more advantageous effect when driven under low electrolyte concentrations, but the present invention is not limited thereto.

[0064] In yet another embodiment of the present invention, the R 1 and R 2 If the alkyl groups have the same number of carbon atoms, then R 1 and R 2 While halogen-substituted alkyl groups, such as fluorine-substituted alkyl groups, specifically 2,2,2-trifluoroethyl groups, may exhibit a more advantageous effect for driving under low electrolyte concentrations, the present invention is not limited thereto.

[0065] In one embodiment of the present invention, the electrolyte for the lithium-sulfur battery may not contain 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether as the acyclic ether. That is, the content of 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether in the electrolyte for the lithium-sulfur battery may be 0% by weight. It is preferable that the electrolyte for the lithium-sulfur battery not contain 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether, as this may cause a decrease in battery performance, but the present invention is not limited thereto.

[0066] In one embodiment of the present invention, the above-mentioned types of acyclic ethers can act as non-solvents for polysulfides eluted from the positive electrode, thereby exhibiting an advantageous effect in that they suppress the elution of polysulfides from the positive electrode. As a result, the acyclic ethers can exhibit an advantageous effect in operating lithium-sulfur batteries at low electrolyte concentrations, but the mechanism of the present invention is not limited in any way to this.

[0067] The glycol ether is an acyclic ether containing two oxygen atoms and can be used without particular limitations as long as it is suitable for use as an electrolyte in a lithium-sulfur battery.

[0068] In one embodiment of the present invention, the glycol ether may be represented by the following chemical formula 2: [Chemical formula 2] R 3 -O-(CH2CH2O) y -R 4 (In the above chemical formula 2, R 3 and R 4 These are either identical or different from each other, and each independently consists of an unsubstituted or substituted alkyl group from C1 to C6, or C6 to C 12 It is an unsubstituted or substituted aryl group, or C7~C 13(This is an unsubstituted or substituted arylalkyl group, where x is an integer from 1 to 4, and y is an integer from 0 to 4.)

[0069] The glycol ether may include, for example, dimethoxyethane, diethoxyethane, ethylene glycol ethyl methyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol methyl ethyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, triethylene glycol methyl ethyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, tetraethylene glycol methyl ethyl ether, polyethylene glycol dimethyl ether, polyethylene glycol diethyl ether, polyethylene glycol methyl ethyl ether, or two or more of these, but is not limited thereto.

[0070] The cyclic ether is an ether containing at least one oxygen atom (O) or sulfur atom (S) in its ring structure and at least one -COC- or -CSC- structure in its ring structure, and can be used as an electrolyte for a lithium-sulfur battery, without any particular limitations. The cyclic ether may, for example, include furan, 2-methylfuran, 3-methylfuran, 2-ethylfuran, 2-propylfuran, 2-butylfuran, 2,3-dimethylfuran, 2,4-dimethylfuran, 2,5-dimethylfuran, pyran, 2-methylpyran, 3-methylpyran, 4-methylpyran, benzofuran, 2-(2-nitrovinyl)furan, thiophene, 2-methylthiophene, 2-ethylthiophene, 2-propylthiophene, 2-butylthiophene, 2,3-dimethylthiophene, 2,4-dimethylthiophene, 2,5-dimethylthiophene, or two or more of these, but is not limited thereto.

[0071] The lithium salt can be used without particular limitations, as long as it is generally suitable for use as an electrolyte in lithium-sulfur batteries. Examples of lithium salts include LiCl, LiBr, LiI, LiClO4, LiBF4, and LiB 10 Cl 10 It may contain, but is not limited to, LiPF6, LiCF3SO3, LiCF3CO2, LiC4BO8, LiAsF6, LiSbF6, LiAlCl4, CH3SO3Li, CF3SO3Li, (CF3SO2)2NLi, (C2F5SO2)2NLi, (SO2F)2NLi, (CF3SO2)3Cli, lithium chloroborane, lithium lower aliphatic carboxylate, lithium 4-phenylborate, lithium imide, or two or more of these.

[0072] In one embodiment of the present invention, the lithium salt may not include lithium nitrate salts. The lithium nitrate salts may be included as examples of nitric acid or nitrite compounds, as described later.

[0073] In one embodiment of the present invention, the lithium salt may include lithium bis(fluorosulfonyl)imide (LiFSI).

[0074] In one embodiment of the present invention, the concentration of the lithium salt can be appropriately determined considering ionic conductivity, solubility, etc., and may be, for example, 0.1 to 4.0 M, 0.5 to 2.0 M, 0.5 to 1.0 M, or 0.75 M. When the concentration of the lithium salt is within the above range, it can exhibit advantageous effects in terms of ionic conductivity and electrolyte viscosity, but is not limited to these.

[0075] In one embodiment of the present invention, when the acyclic ether is present in a high content relative to the total volume of the non-aqueous solvent, the rate of decrease in battery life due to repeated charge-discharge cycles increases sharply when operating a battery using this solvent at a low electrolyte concentration. Therefore, the acyclic ether may be present in a content of 20% by volume or less based on the total volume of the non-aqueous solvent. Specifically, the content of the acyclic ether may be 18% by volume or less, 15% by volume or less, 12% by volume or less, 10% by volume or less, 8% by volume or less, or 5% by volume or less based on the total volume of the non-aqueous solvent. Furthermore, within the above range, it may be present in a content of 1% by volume or more or 3% by volume or more. When the volume of the acyclic ether is within the above range, it can exhibit advantageous effects for operating a lithium-sulfur battery using this solvent at a low electrolyte concentration, but the present invention is not particularly limited thereto.

[0076] In another embodiment of the present invention, the glycol ether content may be 65% by volume or more based on the total volume of the non-aqueous solvent, and the sum of the cyclic ether and acyclic ether content may be 35% by volume or less. Here, the acyclic ether content may be 20% by volume or less based on the total volume of the non-aqueous solvent.

[0077] In another embodiment of the present invention, based on the total volume of the non-aqueous solvent, the glycol ether content may be 65% to 85% or 70% to 80% by volume, and the sum of the cyclic ether and acyclic ether content may be 15% to 35% or 20% to 30% by volume. Here, based on the total volume of the non-aqueous solvent, the acyclic ether content may be 1% to 20% by volume, 3% to 15% by volume, or 5% to 10% by volume.

[0078] In other embodiments of the present invention, when the volume ratios of the glycol ether, cyclic ether, and acyclic ether are within the range described above, the lithium sulfur battery using this can exhibit advantageous effects for operation at low electrolyte concentrations, but the present invention is not particularly limited thereto.

[0079] In one embodiment of the present invention, the ratio of the total volume of glycol ether to the total volume of acyclic ether may be 5 or more. When the acyclic ether is contained in the non-aqueous solvent in the above-mentioned ratio to the volume of glycol ether, it can exhibit advantageous effects in terms of preventing overvoltage at SOC70 when operating a battery using this solvent at a low electrolyte concentration, but the present invention is not particularly limited thereto.

[0080] In one embodiment of the present invention, the ratio of the total volume of the glycol ether to the total volume of the acyclic ether may be 5.5 or more. Specifically, the ratio of the total volume of the glycol ether to the total volume of the acyclic ether may be 6 or more, 6.5 or more, 7 or more, 7.5 or more, or 8 or more. More specifically, the ratio of the total volume of the glycol ether to the total volume of the acyclic ether may be, for example, 5 to 15, 5 to 13, 5 to 10, 6 to 10, 6.5 to 10, 7 to 10, or 8 to 10.

[0081] In another embodiment of the present invention, the acyclic ether is included in an amount of 10% by volume or less based on the total volume of the non-aqueous solvent, and the ratio of the total volume of the glycol ether to the total volume of the acyclic ether may be 6.5 or more.

[0082] In one embodiment of the present invention, the non-aqueous solvent may include dimethoxyethane, 2-methylfuran, and dipropyl ether.

[0083] In another embodiment of the present invention, the non-aqueous solvent may include dimethoxyethane, 2-methylfuran, and ethyl t-butyl ether.

[0084] In yet another embodiment of the present invention, the non-aqueous solvent may include dimethoxyethane, 2-methylfuran, and methylhexyl ether.

[0085] In yet another embodiment of the present invention, the non-aqueous solvent may include dimethoxyethane, 2-methylfuran, and bis-(2,2,2-trifluoroethyl) ether.

[0086] In one embodiment of the present invention, the electrolyte for the lithium-sulfur battery may further contain, in addition to the composition described above, a nitrate compound, a nitrite compound, or a mixture thereof. The nitrate compound or nitrite-based compound can, for example, form a stable film on the negative electrode of a material such as lithium metal, thereby improving charge-discharge efficiency, but the mechanism of the present invention is not limited in any way to this.

[0087] The nitrate or nitrite compounds mentioned above are not particularly limited in the present invention, but may include, for example, inorganic nitrates or nitrite compounds such as lithium nitrate (LiNO3), potassium nitrate (KNO3), cesium nitrate (CsNO3), barium nitrate (Ba(NO3)2), ammonium nitrate (NH4NO3), lithium nitrite (LiNO2), potassium nitrite (KNO2), cesium nitrite (CsNO2), and ammonium nitrite (NH4NO2); organic nitrates or nitrite compounds such as methyl nitrate, dialkylimidazolium nitrate, guanidine nitrate, imidazolium nitrate, pyridinium nitrate, ethyl nitrite, propyl nitrite, butyl nitrite, pentyl nitrite, and octyl nitrite; organic nitro compounds such as nitromethane, nitropropane, nitrobutane, nitrobenzene, dinitrobenzene, nitropyridine, dinitropyridine, nitrotoluene, and dinitrotoluene, or mixtures of two or more of these.

[0088] In one embodiment of the present invention, the electrolyte for the lithium-sulfur battery may further contain lithium nitrate (LiNO3).

[0089] In other embodiments of the present invention, the electrolyte for the lithium-sulfur battery may further contain other additives in addition to the composition described above, with the aim of improving charge-discharge characteristics, flame retardancy, and other properties. Examples of such additives are not particularly limited in the present invention, but include pyridine, triethyl phosphite, triethanolamine, ethylenediamine, n-glyme, hexaphosphate triamide, nitrobenzene derivatives, sulfur, quinone imine dyes, N-substituted oxazolidinone, N,N-substituted imidazolidine, ammonium salts, pyrrole, 2-methoxyethanol, aluminum trichloride, fluoroethylene carbonate (FEC), propensultone (PRS), vinylene carbonate (VC), and the like.

[0090] The electrolyte for the lithium-sulfur battery according to one aspect of the present invention can be manufactured by conventional methods known in the industry, and the present invention is not particularly limited thereto.

[0091] A lithium-sulfur battery according to another aspect of the present invention comprises an electrolyte for lithium-sulfur batteries as described above, a positive electrode comprising a positive electrode active material, and a negative electrode comprising a negative electrode active material.

[0092] A lithium-sulfur battery according to another aspect of the present invention may have an EL (electrolyte) / S (sulfur) ratio (El / S ratio), which is the ratio of the electrolyte to the positive electrode active material, of 2.5 or less.

[0093] In one embodiment of the present invention, the electrolyte for lithium-sulfur batteries described above can exhibit excellent driving characteristics even under low electrolyte concentration conditions, and therefore, a lithium-sulfur battery using it can achieve the effect of realizing a battery with a low electrolyte concentration or high energy density.

[0094] In one embodiment of the present invention, the lithium-sulfur battery can exhibit excellent performance even under conditions where the El / S ratio is 2.3 or less, 2.2 or less, 2.1 or less, or 2.0 or less, but the present invention is not particularly limited thereto. It should be obvious to an ordinary engineer that the lithium-sulfur battery can exhibit excellent performance even when operating under low electrolyte concentrations, and that it also exhibits excellent performance in batteries with El / S ratios even higher than those mentioned above.

[0095] In one embodiment of the present invention, the lithium-sulfur battery may exhibit excellent performance even under conditions where the El / S ratio is 1.5 or higher and 2.5 or lower, or 1.8 or higher and 2.2 or lower.

[0096] The positive electrode, positive electrode active material, negative electrode, and negative electrode active material can be used without particular limitations, as long as they are suitable for use in a lithium-sulfur battery and do not impair the objectives of the present invention.

[0097] For example, the positive electrode may include a positive electrode current collector and a positive electrode active material layer coated on one or both sides of the positive electrode current collector, and the negative electrode may include a negative electrode current collector and a negative electrode active material layer coated on one or both sides of the negative electrode current collector. In this case, the positive electrode current collector is not particularly limited as long as it supports the positive electrode active material, does not cause chemical changes in the battery, and has high conductivity, and the negative electrode current collector is not particularly limited as long as it supports the negative electrode active material, does not cause chemical changes in the battery, and has high conductivity.

[0098] In one aspect of the present invention, the positive electrode active material may include, for example, an element of sulfur, a sulfur compound, or a mixture thereof. Specifically, the positive electrode active material may include inorganic sulfur, Li2S n (n≧1), disulfide compounds, organosulfur compounds, carbon-sulfur polymers ((C2S x ) n , x=2.5~50, n≧2), or may include two or more of these.

[0099] In one embodiment of the present invention, the negative electrode active material is lithium (Li + Any material that can be reversibly intercalated or deintercalated, or that can react with lithium ions to reversibly form a lithium-containing compound, can be used without particular limitation. For example, the negative electrode active material may include lithium metal, lithium alloy, or a mixture thereof. The lithium alloy may be, for example, an alloy of lithium (Li) with sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), francium (Fr), beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), radium (Ra), aluminum (Al), tin (Sn), or two or more of these metals.

[0100] Furthermore, the positive electrode active material layer and the negative electrode active material layer may each contain, in addition to the active material, conductive materials, binders, and additives. Since ordinary types of these materials can be used, their specific types will not be explained.

[0101] The present invention will be described in more detail below with reference to examples, but these examples are merely illustrative and the scope of the present invention is not limited in any way to them.

[0102] Experimental Example 1. Evaluation of battery operating characteristics according to the composition of non-aqueous solvents. First, a lithium-sulfur battery in the form of a pouch cell was manufactured using the method described below, and then its driving characteristics were evaluated.

[0103] [Manufacturing of lithium-sulfur batteries] Example 1 Manufacturing of electrolytes for lithium-sulfur batteries Dimethoxyethane (DME) was mixed with 0.75 M lithium bis(fluorosulfonyl)imide (LiFSI) and 4.0 wt% lithium nitrate (LiNO3), and the mixture was stirred for 12 hours until dissolved. Then, 2-methylfuran and dipropyl ether were added and stirred to produce the electrolyte.

[0104] The volume ratio of dimethoxyethane:2-methylfuran:dipropyl ether used at this time was 80:10:10.

[0105] Manufacturing of positive electrodes A cathode slurry was prepared by mixing a sulfur-carbon complex (S:C=75:25 (weight ratio)) as the cathode active material and lithium polyacrylate (LiPAA) as the binder in a weight ratio of 95:5 using distilled water as the solvent.

[0106] The manufactured positive electrode slurry composition was applied to both surfaces of a 12 μm thick aluminum current collector, dried at 80°C, and rolled using a roll press to produce the positive electrode. At this time, the loading amount of positive electrode active material was 3.5 mAh / cm². 2 That was the case.

[0107] Manufacturing of negative electrodes A 60 μm thick layer of lithium metal was prepared as the negative electrode.

[0108] Manufacturing of lithium-sulfur batteries The negative electrode prepared above was positioned facing the two positive electrodes manufactured above, and a polyethylene separator with a thickness of 16 μm and a porosity of 68% was sandwiched between the positive and negative electrodes. The cells were then stacked to assemble a pouch cell. The N / P ratio at this time was 1.754. Next, 0.86 ml of the electrolyte manufactured above was injected so that the El / S (Electrolyte / S loading amount) ratio was 2.1 ml / g, and the pouch was sealed to manufacture a lithium sulfur battery. The manufactured battery had a capacity of 0.6 Ah, an energy of 1.29 Wh, and an energy-to-electrolyte ratio of 455 Wh / kg.

[0109] Example 2 A lithium sulfur battery was manufactured in the same manner as in Example 1, except that ethyl t-butyl ether was used instead of dipropyl ether.

[0110] Example 3 A lithium sulfur battery was manufactured in the same manner as in Example 1, except that methylhexyl ether was used instead of dipropyl ether.

[0111] Comparative Example 1 A lithium sulfur battery was manufactured in the same manner as in Example 1, except that dibutyl ether was used instead of dipropyl ether.

[0112] [Evaluation Method and Results] Figure 1 shows the results of evaluating the batteries of Examples 1 to 3 and Comparative Example 1, manufactured as described above, when subjected to one cycle of 0.1C charging / 0.1C discharging (upper limit 2.5V / lower limit 1.8V) at a temperature of 25°C.

[0113] Furthermore, Figure 2 shows the results of evaluating the discharge capacity of the batteries manufactured in Examples 1 to 3 and Comparative Example 1 at 25°C, after operating them three times each at 0.1C, 0.2C, 0.3C, and 0.5C for the initial 12 cycles, and then operating them again at 0.1C, according to the number of cycles of the batteries.

[0114] As is clear from Figures 1 and 2, when dipropyl ether, ethyl t-butyl ether, or methylhexyl ether is used as the acyclic ether, excellent performance is observed even when the battery is manufactured and operated with an El / S ratio of 2.1. In contrast, when dibutyl ether is used as the acyclic ether, it was confirmed that the battery stability, according to the battery capacity and charge / discharge cycle, is poor when the battery is manufactured and operated with an El / S ratio of 2.1.

[0115] Experimental Example 2. Evaluation of battery drive characteristics according to the content of acyclic ether. First, a pouch-cell type lithium-sulfur battery was manufactured using the following method, and then its driving characteristics were evaluated.

[0116] [Manufacturing of lithium-sulfur batteries] Example 4 Manufacturing of electrolytes for lithium-sulfur batteries Dimethoxyethane (DME) was mixed with 0.75 M lithium bis(fluorosulfonyl)imide (LiFSI) and 4.0 wt% lithium nitrate (LiNO3), and the mixture was stirred for 12 hours to dissolve. Then, 2-methylfuran and bis-(2,2,2-trifluoroethyl) ether were added and stirred to produce the electrolyte.

[0117] The volume ratio of dimethoxyethane:2-methylfuran:bis-(2,2,2-trifluoroethyl) ether used in this test was 85:10:5.

[0118] Manufacturing of positive electrodes A cathode slurry was prepared by mixing a sulfur-carbon complex (S:C=75:25 (weight ratio)) as the cathode active material and lithium polyacrylate (LiPAA) as the binder in a weight ratio of 95:5 using distilled water as the solvent.

[0119] The manufactured positive electrode slurry composition was applied to both surfaces of a 12 μm thick aluminum current collector, dried at 80°C, and rolled using a roll press to produce the positive electrode. At this time, the loading amount of positive electrode active material was 3.5 mAh / cm². 2 That was the case.

[0120] Manufacturing of negative electrodes A 60 μm thick layer of lithium metal was prepared as the negative electrode.

[0121] Manufacturing of lithium-sulfur batteries The negative electrode prepared above was positioned facing the two positive electrodes manufactured above, and a polyethylene separator with a thickness of 16 μm and a porosity of 68% was sandwiched between the positive and negative electrodes. The cells were then stacked to assemble a pouch cell. The N / P ratio at this time was 2. After this, 0.82 ml of the electrolyte manufactured above was injected so that the El / S (Electrolyte / S loading amount) ratio was 2.0 ml / g, and the pouch was sealed to manufacture a lithium sulfur battery. The manufactured battery had a capacity of 0.6 Ah, an energy of 1.29 Wh, and an energy-to-electrolyte ratio of 465 Wh / kg.

[0122] Example 5 A lithium sulfur battery was manufactured in the same manner as in Example 4, except that the volume ratio of dimethoxyethane:2-methylfuran:bis-(2,2,2-trifluoroethyl) ether was 80:10:10.

[0123] Example 6 A lithium sulfur battery was manufactured in the same manner as in Example 4, except that the volume ratio of dimethoxyethane:2-methylfuran:bis-(2,2,2-trifluoroethyl) ether was 75:10:15.

[0124] Example 7 A lithium sulfur battery was manufactured in the same manner as in Example 4, except that the volume ratio of dimethoxyethane:2-methylfuran:bis-(2,2,2-trifluoroethyl) ether was 70:10:20.

[0125] Comparative Example 2 A lithium sulfur battery was manufactured in the same manner as in Example 4, except that bis-(2,2,2-trifluoroethyl) ether was replaced with an equal amount of 2-methylfuran, and an electrolyte with a volume ratio of dimethoxyethane:2-methylfuran of 85:15 was used.

[0126] [Evaluation Method and Results] Figure 3 shows the results of evaluating the discharge capacity of the batteries of Examples 4-7 and Comparative Example 2 manufactured above, when they were operated three times at a temperature of 25°C with 0.1C charging and 0.1C discharging (with an upper limit of 2.5V and a lower limit of 1.8V).

[0127] Furthermore, Figure 4 shows the results of evaluating the discharge capacity according to the number of cycles of the batteries manufactured in Examples 4 to 7 and Comparative Example 2 above. These batteries were operated three times at 0.1C at 25°C, then once each at 0.1C, 0.2C, 0.3C, and 0.5C, and then again at 0.1C.

[0128] As is clear from Figure 3, it was confirmed that in Examples 4 and 5, the overvoltage could be improved compared to Comparative Example 2.

[0129] On the other hand, as is clear from Figure 4, when an acyclic ether is used, it was confirmed that the lifetime characteristics according to the charge / discharge cycle can be further improved in the order of 20% by volume (Example 7) < 15% by volume (Example 6) < 10% by volume (Example 5) ≤ 5% by volume (Example 4), based on 100% by volume of the total solvent.

Claims

1. It comprises a lithium salt and a non-aqueous solvent, The aforementioned non-aqueous solvent is It comprises glycol ethers, cyclic ethers, and acyclic ethers represented by the following chemical formula 1. The cyclic ether contains at least one oxygen atom or sulfur atom in its ring structure. The aforementioned cyclic ether consists of furan, 2-methylfuran, 3-methylfuran, 2-ethylfuran, 2-propylfuran, 2-butylfuran, 2,3-dimethylfuran, 2,4-dimethylfuran, 2,5-dimethylfuran, pyran, 2-methylpyran, 3-methylpyran, 4-methylpyran, benzofuran, 2-(2-nitrovinyl)furan, or two or more of these. The aforementioned acyclic ether is an electrolyte for lithium-sulfur batteries, comprising a fluorine-free acyclic ether. [Chemical formula 1] R １ -O-R ２ (In the above chemical formula 1, R １ C is either unsubstituted or substituted. １ ~C ３ It is an alkyl group, R ２ C is either unsubstituted or substituted. ２ ~C ２０ It is an alkyl group.

2. Said R １ is an unsubstituted or substituted C １ -C ２ alkyl group, The aforementioned R ２ This is an unsubstituted C ４ ~C １０ alkyl group, or substituted C ２ ~C １０ The electrolyte for a lithium sulfur battery according to claim 1, wherein the alkyl group is...

3. The electrolyte for a lithium sulfur battery according to claim 1, wherein the fluorine-free acyclic ether comprises methyl propyl ether, ethyl propyl ether, dipropyl ether, methyl butyl ether, methyl hexyl ether, ethyl butyl ether, ethyl hexyl ether, or a mixture of two or more thereof.

4. The electrolyte for the lithium-sulfur battery according to claim 1, wherein the electrolyte for the lithium-sulfur battery does not contain 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether.

5. The electrolyte for a lithium sulfur battery according to claim 1, wherein the glycol ether comprises dimethoxyethane, diethoxyethane, ethylene glycol ethyl methyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol methyl ethyl ether, triethylene glycol dimethyl ether, triethylene glycol diethyl ether, triethylene glycol methyl ethyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, tetraethylene glycol methyl ethyl ether, polyethylene glycol dimethyl ether, polyethylene glycol diethyl ether, polyethylene glycol methyl ethyl ether, or two or more of these.

6. The electrolyte for a lithium sulfur battery according to claim 1, wherein the cyclic ether is 2-methylfuran.

7. The lithium salts mentioned above are LiCl, LiBr, LiI, and LiClO ４ LiBF ４ LiB １０ Cl １０ LiPF ６ LiCF ３ SO ３ LiCF ３ CO ２ LiC ４ BO ８ LiAsF ６ LiSbF ６ LiAlCl ４ ,CH ３ SO ３ Li, CF ３ SO ３ Li, (CF ３ SO ２ ) ２ NLi, (C ２ F ５ SO ２ ) ２ NLi, (SO ２ F) ２ NLi, (CF ３ SO ２ ) ３ An electrolyte for a lithium-sulfur battery according to claim 1, comprising CLI, lithium chloroborane, lithium lower aliphatic carboxylate, lithium tetraphenylborate, lithium imide, or two or more of these.

8. The electrolyte for a lithium sulfur battery according to claim 1, wherein the acyclic ether is contained in a content of 20% by volume or less based on the total volume of the non-aqueous solvent.

9. The electrolyte for a lithium sulfur battery according to claim 1, wherein the acyclic ether is contained in a content of 1% by volume or more and 15% by volume or less, based on the total volume of the non-aqueous solvent.

10. Based on the total volume of the non-aqueous solvent, the glycol ether content is 65% by volume or more, and the sum of the cyclic ether and acyclic ether content is 35% by volume or less. The electrolyte for a lithium sulfur battery according to claim 1, wherein the content of the acyclic ether is 20% by volume or less based on the total volume of the non-aqueous solvent.

11. The electrolyte for a lithium-sulfur battery according to claim 1, further comprising a nitrate compound, a nitrite compound, or a mixture thereof.

12. An electrolyte for a lithium sulfur battery according to any one of claims 1 to 11, A positive electrode containing a positive electrode active material, A negative electrode containing a negative electrode active material, Lithium sulfur batteries, including those containing lithium sulfur.

13. The lithium sulfur battery according to claim 12, wherein the ratio of the electrolyte to the positive electrode active material (El / S ratio) is 2.5 or less.

14. The lithium sulfur battery according to claim 12, wherein the positive electrode active material comprises a sulfur element, a sulfur compound, or a mixture thereof.

15. The positive electrode active material is inorganic sulfur (S ８ ), Li ２ Sn (n≧1), disulfide compounds, organosulfur compounds, carbon-sulfur polymers ((C ２ S ｘ ) ｎ The lithium sulfur battery according to claim 12, wherein x is an integer between 2.5 and 50, and n ≥ 2), or comprises two or more of these.

16. The lithium sulfur battery according to claim 12, wherein the negative electrode active material comprises lithium metal, a lithium alloy, or a mixture thereof.

17. The lithium sulfur battery according to claim 12, wherein the positive electrode contains lithium polyacrylate (LiPAA).

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