Rechargeable lithium battery and method of forming the same

Abstract

Rechargeable lithium batteries and methods of forming rechargeable lithium batteries are provided. A rechargeable lithium battery includes: a positive electrode including a positive active material and sulfur; a negative electrode including a negative electrode active material and sulfur; and a non-aqueous electrolyte. The amount of sulfur in the positive electrode is at least twice the amount of sulfur in the negative electrode.

Description

Technical Field

[0001] According to one or more embodiments, the present disclosure relates to a rechargeable lithium battery and a method of forming the same. Background Art

[0002] Rechargeable lithium batteries, which have relatively high energy density and are lightweight and easy to carry, are mainly used as driving power sources for mobile information terminals such as mobile phones, notebook computers, and / or smart phones.

[0003] Rechargeable lithium batteries are generally manufactured by using materials that can reversibly intercalate and deintercalate lithium ions as positive and negative active materials. An electrolyte is provided between a positive electrode including the positive active material and a negative electrode including the negative active material.

[0004] Lithium transition metal oxides are used as positive active materials of rechargeable lithium batteries, one or more suitable types (kinds) of carbon-based materials are used as negative active materials, and lithium salts dissolved in non-aqueous organic solvents are used as electrolytes.

[0005] For example, a rechargeable lithium battery exhibits suitable battery characteristics by utilizing complex reactions such as reactions between a positive electrode and an electrolyte and / or a negative electrode and an electrolyte, etc. Therefore, utilizing a suitable electrolyte is one of the important parameters for improving the performance of a rechargeable lithium battery. Summary of the invention

[0006] One or more aspects relate to a rechargeable lithium battery that exhibits reduced resistance and suppressed or reduced gas generation during storage (e.g., allowed to stand) at high temperatures. One or more possible additional aspects may be set forth in part in the following description and in part will be apparent from the description, or may be learned by practicing the disclosed presented embodiments.

[0007] One or more embodiments provide a rechargeable lithium battery comprising: a positive electrode including a positive electrode active material and sulfur; a negative electrode including a negative electrode active material and sulfur; and a non-aqueous electrolyte, wherein the amount of sulfur included in the positive electrode is approximately at least twice the amount of sulfur included in the negative electrode.

[0008] The amount of sulfur included in the positive electrode may be about two to five times the amount of sulfur included in the negative electrode.

[0009] The sulfur may be included in the positive electrode in an amount of about 0.01 wt % to about 0.7 wt % based on the total 100 wt % of the rechargeable lithium battery.

[0010] The amount of sulfur included in the negative electrode may be greater than 0 wt % and up to about 0.33 wt % based on the total 100 wt % of the rechargeable lithium battery.

[0011] The positive electrode active material may be a compound represented by Chemical Formula 1;

[0012] Chemical formula 1

[0013] Li a1 Ni x1 Co y1 A z1 O2

[0014] Among them, 0.9≤a1≤1.1, 0.88≤x1≤0.98, 0.01≤y1≤0.11, 0.01≤z1≤0.11, x1+y1+z1=1, and A can be Mn or Al.

[0015] A rechargeable lithium battery may be a battery configured for (eg, subjected to) formation charge and discharge.

[0016] The positive electrode may include the additive represented by Chemical Formula 2 or at least one additive selected from Chemical Formulas 3 to 5.

[0017] Chemical formula 2

[0018]

[0019] in,

[0020] A1, A2, A3 and A4 can all be independently selected from the following: a covalent bond; a C1 to C5 alkylene group substituted or unsubstituted by a substituent; a carbonyl group; and a sulfinyl group, provided that A1 and A2 are not covalent bonds at the same time (e.g., concurrently), and A3 and A4 are not covalent bonds at the same time (e.g., concurrently).

[0021] Chemical formula 3

[0022]

[0023] Chemical formula 4

[0024]

[0025] Chemical formula 5

[0026]

[0027] The rechargeable lithium battery according to one or more embodiments may exhibit suppressed or reduced gas generation and reduced resistance during the period during which it is allowed to stand at high temperature.

[0028] One or more aspects relate to methods of forming a rechargeable lithium battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings are schematic diagrams showing a rechargeable lithium battery according to one or more embodiments of the present disclosure. DETAILED DESCRIPTION

[0030] Hereinafter, one or more suitable embodiments of the present disclosure will be described in more detail with reference to the accompanying drawings, so that those skilled in the art can easily implement the present disclosure. However, the present disclosure can be implemented in many different forms and is not to be construed as being limited to the example embodiments set forth herein. Therefore, the embodiments are described only by reference to the accompanying drawings to explain aspects of this specification. If a statement such as "at least one (kind / person) of ... " is before / after a column of elements (for example, when a statement such as "at least one (kind / person) of ... " is before / after a column of elements), the entire column of elements is modified without modifying the individual elements of the column.

[0031] The terms used in the specification are used to explain the embodiments, but are not intended to limit the present disclosure. Unless the context clearly indicates otherwise, the expression in the singular includes the expression in the plural. Unless otherwise defined, all terms (including chemical terms, technical terms and scientific terms) used herein have the same meaning as the meaning generally understood by those of ordinary skill in the art to which the application belongs. In addition, it will also be understood that terms (such as those defined in common dictionaries) should be interpreted as having the same meaning as their meaning in the context of the relevant field, and will not be interpreted with an idealized or overly formalized meaning, unless so clearly defined herein.

[0032] Example embodiments are described herein with reference to schematic cross-sectional views of ideal embodiments. As such, variations in the shapes of the illustrations caused by, for example, manufacturing techniques and / or tolerances are expected. Therefore, example embodiments should not be interpreted as being limited to the specific shapes of the regions shown herein, but will include shape deviations caused by, for example, manufacturing. For example, a region shown or described as flat may typically have rough and / or nonlinear features. In addition, the sharp angles shown may be rounded (rounded). Therefore, the regions shown in the drawings are schematic in nature, and their shapes are not intended to illustrate the actual shape of the regions of the device, and are not intended to limit the scope of the claims.

[0033] Throughout the specification, if a component such as a layer, film, region or plate is described as being "above" or "on" another component (for example, when a component such as a layer, film, region or plate is described as being "above" or "on" another component), the component may be directly above the other component, or there may be another component(s) therebetween. It will be understood that, although the terms "first" and / or "second" etc. may be used herein to describe one or more suitable elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. The terms described are only used to distinguish one component from another. Components having substantially the same functional configuration in this specification and the drawings are represented by the same reference numerals, and redundant descriptions thereof will not be provided.

[0034] However, the present disclosure may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. Embodiments are provided so that the present disclosure will be thorough and complete, and will fully convey the scope of the present disclosure to those skilled in the art. The same reference numerals in the accompanying drawings represent the same elements, and their repeated description may not be provided.

[0035] As used herein, if expressions such as “at least one of…,” “one of…,” and “selected from…” precede / follow a list of elements (for example, when expressions such as “at least one of…,” “one of…,” and “selected from…” precede / follow a list of elements), they modify the entire list of elements without modifying the individual elements of the list. For example, the expressions “at least one of a to c” and “at least one of a, b, and c” may mean only a, only b, only c, both a and b (for example, simultaneously), both a and c (for example, simultaneously), both b and c (for example, simultaneously), all of a, b, and c, or variations thereof.

[0036] The term "may" will be understood to mean that some of the "one or more embodiments of the present disclosure" include the described elements, and some of the "one or more embodiments of the present disclosure" exclude the elements and / or include alternative elements. Similarly, alternative language such as "or" means that the "one or more embodiments of the present disclosure" each include the corresponding listed items.

[0037] Although the terms "first", "second" and / or "third" etc. may be used herein to describe one or more suitable elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Therefore, without departing from the teachings of the present disclosure, the first element, component, region, layer or part discussed may be referred to as a second element, component, region, layer or part.

[0038] The terms used herein are only used for the purpose of describing specific embodiments and are not intended to limit the present disclosure. As used herein, unless otherwise noted, the expressions "one", "one (kind / person)" and "the (the)" used in the singular are intended to include plural forms and include the expression "at least one (kind / person) in ... ". "At least one (kind / person) in ... should not be interpreted as a singular. As used herein, the term "and / or" includes any combination and all combinations of one or more of the relevant listed items. Terms such as "including", "comprising", "having" and / or their variations are intended to indicate the presence of features, regions, wholes, processes, components and / or elements disclosed in the specification, and are not intended to exclude the possibility that one or more other features, regions, wholes, processes, components and / or elements may exist or may be added.

[0039] In order to easily describe the relationship of one element or feature to another element or feature(s) as shown in the drawings, spatially relative terms such as "below," "below," "above," "above," or "on" may be utilized herein. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the drawings. For example, if the device in the drawings is flipped (e.g., when the device in the drawings is flipped), elements described as "below" other elements or features will subsequently be positioned as "above" the other elements or features. The device may be otherwise positioned (rotated 90 degrees or at other orientations), and the spatially relative descriptors utilized herein interpreted accordingly.

[0040] As used herein, "consisting essentially of" means that any additional components will not substantially affect the chemical, physical, optical, or electrical properties of the semiconductor film.

[0041] Furthermore, in this specification, the phrase "on a plane" or "plan view" means viewing a target portion from the top, and the phrase "on a cross section" means viewing a cross section formed by vertically cutting the target portion from the side.

[0042] The terms "comprises", "includes", "has" and / or variations thereof are intended to indicate the presence of a characteristic, quantity, step, constituent element (element) or a combination thereof that is performed, but it should be understood that the possibility of the presence or addition of one or more other characteristics, quantities, steps, constituent elements (elements) or a combination thereof is not precluded.

[0043] The drawings show exaggerated thicknesses in order to clearly show one or more appropriate layers and regions, and throughout the specification, similar parts are given the same reference numerals. If an element such as a layer, film, region and / or plate is referred to as being "on" or "over" another element (for example, when an element such as a layer, film, region and / or plate is referred to as being "on" or "over" another element), it may include not only the case where it is "directly on" the other element, but also the case where there is another element in between. Conversely, if an element is referred to as being "directly on" another element (for example, when an element is referred to as being "directly on" another element), there are no intervening elements.

[0044] definition

[0045] The term "combinations thereof" may include mixtures, stacks, composites, copolymers, alloys, blends, reactants of components.

[0046] If viewed from a plan view (for example, when viewed from a plan view), the term "layer" includes a shape completely formed on the entire surface or a shape formed on a partial surface.

[0047] Here, “or” should not be interpreted as an exclusive meaning, for example, “A or B” is interpreted as including A, B and / or A+B, etc.

[0048] As utilized herein, if no definition is otherwise provided (eg, when no definition is otherwise provided), "copolymer" refers to block copolymer, random copolymer, graft copolymer or alternating copolymer, and "copolymer" refers to block copolymer, random copolymer, graft copolymer or alternating copolymer.

[0049] As used herein, if no definition is provided in addition (e.g., when no definition is provided in addition), the particle diameter (or particle size) can be an average particle diameter (or average particle size). Such a particle diameter represents an average particle diameter or average particle size (D50) in which the cumulative volume is about 50% by volume in the particle size distribution. The average particle size (D50) can be measured by a method that is well suited to those skilled in the art (e.g., by a particle size analyzer or by a transmission electron microscope image or a scanning electron microscope image). In some embodiments, data analysis is performed using a dynamic light scattering measurement device, and the number of particles in each size range is counted, whereby the average particle diameter (D50) value can be easily obtained by calculation.

[0050] D50 refers to a particle diameter corresponding to 50% of particles in a cumulative distribution curve measured by a laser diffraction method in which particles are accumulated in order of particle diameter from the smallest particle to the largest particle.

[0051] D90 refers to a particle diameter corresponding to 90% of particles in a cumulative distribution curve measured by a laser diffraction method in which particles are accumulated in order of particle diameter from the smallest particle to the largest particle.

[0052] D10 refers to a particle diameter corresponding to 10% of particles in a cumulative distribution curve measured by a laser diffraction method in which particles are accumulated in order of particle diameter from the smallest particle to the largest particle.

[0053] The term "group" may refer to the element groups numbered 1 to 18 in the periodic table classified according to the classification system of the International Union of Pure and Applied Chemistry ("IUPAC"). The term "group" may refer to a substituent, for example, "C1 to C5 alkylene".

[0054] As utilized herein, if no definition is otherwise provided (e.g., when no definition is otherwise provided), the term "substituted" may refer to substitution of a hydrogen of a compound with a substituent selected from the group consisting of halogen (F, Cl, Br or I), hydroxyl, alkoxy, nitro, cyano, amino or amine, azido, amidino, hydrazine, hydrazone, carbonyl, carbamoyl, thiol, ester, carboxyl or a salt thereof, sulfonic acid or a salt thereof, phosphate or a salt thereof, C1 to C20 alkyl, C2 to C20 alkenyl, C2 to C20 alkynyl, C6 to C30 aryl, C7 to C30 arylalkyl, C1 to C4 alkoxy, C1 to C20 heteroalkyl, C3 to C20 heteroaryl, C3 to C30 cycloalkyl, C3 to C15 cycloalkenyl, C6 to C15 cycloalkynyl, C2 to C20 heterocycloalkyl, and combinations thereof.

[0055] The term "hetero" may refer to halogen, oxygen, nitrogen, phosphorus, sulfur, silicon, boron, or mixtures thereof.

[0056] Although specific embodiments have been described, the applicant or those skilled in the art may conceive of alternatives, modifications, variations, improvements, and substantial equivalents that are not currently foreseeable or may not currently be foreseeable. Therefore, the appended claims submitted and as may be amended are intended to include all such alternatives, modifications, variations, improvements, and substantial equivalents.

[0057] Hereinafter, a positive active material, a positive electrode, and a rechargeable lithium battery including the same and a method of manufacturing the same will be described in more detail.

[0058] introduction

[0059] A rechargeable lithium battery according to one or more embodiments may include: a positive electrode including a positive active material and sulfur; a negative electrode including a negative active material and sulfur; and a non-aqueous electrolyte. In some embodiments, the amount of sulfur included in the positive electrode is at least about twice the amount of sulfur included in the negative electrode. According to one or more embodiments, the amount of sulfur included in the positive electrode may be about twice (2 times) to about 5 times, about 2.2 times to about 5 times, about 2.5 times to about 5 times, or about 3 times to about 5 times the amount of sulfur included in the negative electrode.

[0060] If sulfur is included in both the positive electrode and the negative electrode (e.g., at the same time) and the amount of sulfur satisfies the described relationship (e.g., when sulfur is included in both the positive electrode and the negative electrode (e.g., at the same time) and the amount of sulfur satisfies the described relationship), the surface of the positive electrode reacts with the electrolyte during charge and discharge, and thus the thin layer formed on the surface of the positive electrode may include sulfide. In this way, even if the battery according to one or more embodiments is allowed to stand at high temperature (e.g., when the battery according to one or more embodiments is allowed to stand at high temperature), the preparation of the thin layer including sulfide can suppress or reduce the increase in resistance, and can also effectively suppress or reduce gas generation. The elution of transition metals from the surface of the positive electrode at high temperature can be suppressed, thereby suppressing the collapse of the active material crystal structure due to the elution of transition metals during charge and discharge.

[0061] If the amount of sulfur included in the positive electrode is the same as the amount of sulfur included in the negative electrode (for example, when the amount of sulfur included in the positive electrode is the same as the amount of sulfur included in the negative electrode), the thickness of the thin layer formed during charge and discharge may increase, which causes an increase in resistance, so that a desired or appropriate effect may not be achieved. In some embodiments, if the amount of sulfur included in the positive electrode is less than the amount of sulfur included in the negative electrode (for example, when the amount of sulfur included in the positive electrode is less than the amount of sulfur included in the negative electrode), a thin layer in which sulfide for suppressing an increase in resistance and gas generation is not sufficiently included is formed, so that a desired or appropriate effect may not be achieved.

[0062] In one or more embodiments, the amount of sulfur in the positive electrode may be about 0.01 wt% to about 0.7 wt%, about 0.03 wt% to about 0.7 wt%, about 0.03 wt% to about 0.5 wt%, about 0.03 wt% to about 0.4 wt%, or about 0.03 wt% to about 0.3 wt%, based on the total 100 wt% of the rechargeable lithium battery. The amount of sulfur in the negative electrode may be greater than 0 wt% and up to about 0.33 wt%, about 0.01 wt% to about 0.33 wt%, about 0.01 wt% to about 0.3 wt%, or about 0.01 wt% to 0.2 wt%, based on the total 100 wt% of the rechargeable lithium battery.

[0063] If the amount of sulfur in the positive electrode is within the described range (for example, when the amount of sulfur in the positive electrode is within the described range), a thin layer including a sulfide component is well formed during charge and discharge, thereby fully suppressing the elution of the transition metal from the surface of the positive electrode and / or the positive active material at high temperature. Therefore, the collapse of the structure of the positive active material due to the elution of the transition metal can be suppressed or reduced, and the side reaction caused by oxidation of the electrolyte on the surface of the positive electrode and / or the positive active material at high voltage and / or high temperature can be further minimized or reduced, so that the excessive generation of the resistive thin layer can be effectively prevented or reduced. If the amount of sulfur in the negative electrode is within the described range (for example, when the amount of sulfur in the negative electrode is within the described range), similar to the positive electrode, the side reaction caused by the reduction of the electrolyte on the surface of the negative electrode and / or the negative active material at high voltage or high temperature can be further minimized or reduced, and the excessive generation of the resistive thin layer can be prevented or reduced.

[0064] The ratio of sulfur included in the positive electrode to sulfur included in the negative electrode may also be obtained after the battery is subjected to formation charge and discharge. The formation charge and discharge may be performed by charging and discharging the rechargeable lithium battery once to three times at about 0.1C to about 0.3C.

[0065] If the positive electrode active material included in the positive electrode is a high nickel positive electrode active material (for example, when the positive electrode active material included in the positive electrode is a high nickel positive electrode active material), the effect obtained by satisfying the described ratio of the amount of sulfur included in the positive electrode to the amount of sulfur included in the negative electrode can be more appropriately obtained. The high nickel positive electrode active material refers to a positive electrode active material in which the amount of nickel is about 88 mol% or more based on about 100 mol% of other metals other than lithium of the metal included in the positive electrode active material. The positive electrode active material according to one or more embodiments can be represented by Chemical Formula 1.

[0066] Chemical formula 1

[0067] Li a1 Ni x1 Co y1 A z1 O2

[0068] in,

[0069] 0.9≤a1≤1.1, 0.88≤x1≤0.98, 0.01≤y1≤0.11, 0.01≤z1≤0.11, x1+y1+z1=1, and A can be Mn or Al. In one embodiment, 0.9≤a1≤1.1, 0.88≤x1≤0.98, 0.01≤y1≤0.08, 0.01≤z1≤0.08, x1+y1+z1=1, and A is Mn or Al.

[0070] If a battery including a high-nickel positive electrode active material is stored (e.g., allowed to stand) at a high temperature (e.g., at least 60° C.) (e.g., when a battery including a high-nickel positive electrode active material is stored (e.g., allowed to stand) at a high temperature (e.g., at least 60° C.), its structure is unstable compared to a cobalt-based or low-nickel positive electrode active material. Therefore, elution of transition metals (such as cobalt, Mn and / or Al, etc.) (particularly, at high temperatures) may occur easily, and thus resistance may increase, and gas may be seriously generated. Therefore, the effect of adjusting the amount of sulfur included in the positive electrode and the negative electrode can be greatly achieved (e.g., obtained or more desired). For example, the effect of reducing resistance at high temperatures due to the inclusion of sulfur in the positive electrode and the negative electrode can be largely achieved (e.g., obtained or more desired).

[0071] Because the cobalt-based or low-nickel positive active material does not cause an increase in resistance when stored at high temperatures, the effect of adjusting the amount of sulfur may not be obtained, and if sulfur is included (e.g., when sulfur is included), it may increase (e.g., actually act as) resistance and is inappropriate (e.g., to be included or may be less desirable).

[0072] Positive electrode

[0073] The positive electrode of the rechargeable lithium battery may include a positive active material layer including a positive active material layer composition. Components of the positive active material layer and the positive active material layer composition are described in more detail herein.

[0074] In such a rechargeable lithium battery, the positive electrode may include a positive active material layer composition and an additive represented by Chemical Formula 2 and / or at least one additive represented by Chemical Formulas 3 to 5. As described in more detail herein, the positive active material layer composition includes a positive active material, a binder, and a conductive material.

[0075] Some embodiments of the present disclosure relate to a method of forming a rechargeable lithium battery. The method may include adding an additive represented by Chemical Formula 2 and / or at least one additive represented by Chemical Formulas 3 to 5 to a positive active material layer composition.

[0076] Chemical formula 2

[0077]

[0078] in,

[0079] A1, A2, A3 and A4 can all be independently selected from: a covalent bond; a C1 to C5 alkylene group substituted or unsubstituted by a substituent; a carbonyl group; and a sulfinyl group, provided that A1 and A2 are not covalent bonds at the same time (e.g., concurrently), and A3 and A4 are not covalent bonds at the same time (e.g., concurrently).

[0080] In one or more embodiments, at least one of A1, A2, A3, and A4 may be an unsubstituted C1 to C5 alkylene group or a substituted C1 to C5 alkylene group.

[0081] Chemical formula 3

[0082]

[0083] Chemical formula 4

[0084]

[0085] Chemical formula 5

[0086]

[0087] The additive represented by Chemical Formula 2 may be represented by Chemical Formula 2a or Chemical Formula 2b.

[0088] Chemical formula 2a

[0089]

[0090] Chemical formula 2b

[0091]

[0092] in,

[0093] Z1, Z2, Z3, Z4, Z5 and Z6 may each independently be: -C(E1)(E2)-; a carbonyl group; or a sulfinyl group,

[0094] E1 and E2 can both be independently selected from the following: hydrogen; halogen; halogen-substituted or unsubstituted C1 to C20 alkyl; halogen-substituted or unsubstituted C2 to C20 alkenyl; halogen-substituted or unsubstituted C2 to C20 alkynyl; halogen-substituted or unsubstituted C3 to C20 cycloalkenyl; halogen-substituted or unsubstituted C3 to C20 heterocyclyl; halogen-substituted or unsubstituted C6 to C40 aryl; and halogen-substituted or unsubstituted C2 to C40 heteroaryl.

[0095] In one or more embodiments, the additive represented by Chemical Formula 2 may be one selected from the compounds represented by Chemical Formulas 6 to 9. For example, the additive represented by Chemical Formula 2 may be a compound represented by Chemical Formula 6.

[0096] Chemical formula 6

[0097]

[0098] Chemical formula 7

[0099]

[0100] Chemical formula 8

[0101]

[0102] Chemical formula 9

[0103]

[0104] If an additive is added to the positive electrode active material layer composition (for example, when the additive is added to the positive electrode active material layer composition), the amount of the additive can be about 0.05wt% to about 2.1wt%, about 0.05wt% to about 1.8wt%, about 0.05wt% to about 1wt%, about 0.05wt% to about 0.9wt%, about 0.05wt% to about 0.5wt%, about 0.6wt% to about 1.8wt%, about 0.7wt% to about 2.1wt%, based on 100wt% of the positive electrode active material layer composition (solid amount) including the positive electrode active material, the binder and the conductive material.

[0105] If an additive is added to the positive electrode active material layer composition to prepare a positive electrode (for example, when an additive is added to the positive electrode active material layer composition to prepare a positive electrode), a suitable thin layer can be formed on the surface of the positive electrode, and if stored at high temperature (for example, when stored at high temperature), the thin layer can inhibit or reduce the reaction, thereby preventing or reducing gas generation and resistance increase.

[0106] Since such an additive is added during the preparation of the positive electrode, sulfur generated by the additive is mainly present in the positive electrode, thereby obtaining an amount of sulfur included in the positive electrode that is at least twice (e.g., or 5 times) the amount of sulfur included in the negative electrode. For example, if a rechargeable lithium battery including such a positive electrode is charged and discharged (e.g., when a rechargeable lithium battery including such a positive electrode is charged and discharged), even if sulfur moves to the negative electrode (e.g., when sulfur moves to the negative electrode), the amount of sulfur included in the negative electrode may be equal to or less than half (i.e., 1 / 2) of the amount in the positive electrode.

[0107] If the additive is added to the electrolyte (for example, when the additive is added to the electrolyte), the sulfur generated by the additive is all distributed in the positive electrode, the electrolyte, and the negative electrode, so that the amount of sulfur included in the positive electrode may not be excessive. For example, the amount of sulfur included in the positive electrode may be two or more times (at least two times) (for example, two to five times) the amount of sulfur in the negative electrode.

[0108] In one or more embodiments, the positive electrode includes a positive active material layer including a positive active material and sulfur, and a current collector supporting the positive active material layer.

[0109] In the positive electrode, the amount of the positive active material may be about 90 wt % to about 98 wt % based on the total weight of the positive active material layer.

[0110] In one or more embodiments, the positive active material layer may include a binder and a conductive material, and the amount of the binder and the conductive material may be about 0.995 wt % to 4.97 wt %, respectively, based on the total weight of the positive active material layer.

[0111] The binder improves the bonding properties between the positive electrode active material particles and between the positive electrode active material particles and the current collector. Examples of the binder may include polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene oxide-containing polymers, polyvinyl pyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, acrylated styrene-butadiene rubber, epoxy resin and / or nylon, but are not limited thereto.

[0112] A conductive material is included to provide electrode conductivity, and any electrically conductive material can be used as the conductive material unless it causes a chemical change. Examples of the conductive material may include: carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, and / or carbon fiber, etc.; metal-based materials of metal powder or metal fiber, including copper, nickel, aluminum, and / or silver, etc.; conductive polymers such as polyphenylene derivatives; or one or more mixtures thereof.

[0113] The current collector may include Al, but is not limited thereto.

[0114] The negative electrode includes a negative active material layer including a negative active material and sulfur and a current collector supporting the negative active material layer.

[0115] The negative electrode active material includes a material that can reversibly intercalate / deintercalate lithium ions, lithium metal, a lithium metal alloy, a material that can be doped / dedoped with lithium, and / or a transition metal oxide.

[0116] The material that reversibly intercalates / deintercalates lithium ions may be a carbon material (e.g., a carbon-based negative electrode active material commonly used in rechargeable lithium batteries). Examples of carbon-based negative electrode active materials may be crystalline carbon, amorphous carbon, or a mixture thereof. Crystalline carbon may be natural graphite or artificial graphite of unspecified shape, flake, flaky, spherical, or fibrous shape. Amorphous carbon may be soft carbon, hard carbon, mesophase pitch carbonization product, and / or burnt coke, etc.

[0117] Lithium metal alloys include alloys of lithium and a metal selected from Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al and Sn.

[0118] The material capable of doping / dedoping lithium can be a silicon-based anode active material or a Sn-based anode active material.

[0119] The silicon-based anode active material can be or include silicon, Si-C composite, SiO x (0 < x < 2) or Si-Q alloy. In some embodiments, Q is an element selected from the group consisting of alkali metals, alkaline earth metals, Group 13 elements, Group 14 elements, Group 15 elements, Group 16 elements, transition metals, rare earth elements, and combinations thereof, and Q excludes (e.g., does not include) Si.

[0120] The Sn-based anode active material can be or include Sn, SnO2, Sn-R alloy, and / or Sn-carbon composite, etc. In some embodiments, R is an element selected from the group consisting of alkali metals, alkaline earth metals, Group 13 elements, Group 14 elements, Group 15 elements, Group 16 elements, transition metals, rare earth elements, and combinations thereof, and R excludes (e.g., does not include) Sn. At least one of these materials can be mixed with SiO2.

[0121] In some embodiments, Q and / or R can be selected from the group consisting of Mg, Ca, Sr, Ba, Ra, Sc, Y, Ti, Zr, Hf, Rf, V, Nb, Ta, Db, Cr, Mo, W, Sg, Tc, Re, Bh, Fe, Pb, Ru, Os, Hs, Rh, Ir, Pd, Pt, Cu, Ag, Au, Zn, Cd, B, Al, Ga, Sn, In, Ge, P, As, Sb, Bi, S, Se, Te, Po, and combinations thereof.

[0122] The transition metal oxide can be or include lithium titanate oxide.

[0123] The Si-C composite can be a composite of silicon and amorphous carbon. The average particle size (D50) of the Si-C composite can be, for example, about 0.5 micrometers (μm) to about 20 μm. According to one or more embodiments, the Si-C composite can be or include silicon particles and amorphous carbon coated on the surface of the silicon particles. For example, the Si-C composite can include secondary particles (cores), silicon primary particles are agglomerated in the secondary particles (e.g., in each secondary particle), and an amorphous carbon coating layer (shell) is located on the surface of each of the secondary particles. Amorphous carbon can also be located between the silicon primary particles, for example, can be coated on the silicon primary particles. The secondary particles can also be distributed in the amorphous carbon.

[0124] The Si-C composite may also include crystalline carbon. For example, the Si-C composite may include a core (e.g., a secondary particle) containing crystalline carbon and silicon particles, and an amorphous carbon coating layer located on the surface of the core. The crystalline carbon may be artificial graphite, natural graphite, or a combination thereof. The amorphous carbon may be soft carbon, hard carbon, mesophase pitch carbide, and / or calcined coke, etc.

[0125] The silicon particles (e.g., silicon primary particles) may be nano-silicon particles. The particle size of the nano-silicon particles may be from about 10 nanometers (nm) to about 1,000 nm, and according to one or more embodiments, may be from about 20 nm to about 900 nm, from about 20 nm to about 800 nm, from about 20 nm to about 500 nm, from about 20 nm to about 300 nm, or from about 20 nm to about 150 nm. If the average particle size of the silicon particles (e.g., silicon primary particles) is within the described range (e.g., when the average particle size of the silicon particles (e.g., silicon primary particles) is within the described range), the extreme volume expansion caused during charge and discharge can be suppressed or reduced, and the destruction of the conduction path due to particle fragmentation can be prevented or reduced.

[0126] If the Si-C composite includes silicon and amorphous carbon (e.g., when the Si-C composite includes silicon and amorphous carbon), based on 100 wt% of the Si-C composite, the amount of silicon may be from about 10 wt% to about 50 wt%, and the amount of amorphous carbon may be from about 50 wt% to about 90 wt%. In another embodiment, the Si-C composite includes silicon, amorphous carbon, and crystalline carbon, and based on 100 wt% of the Si-C composite, the amount of silicon may be from about 10 wt% to about 50 wt%, the amount of crystalline carbon may be from about 10 wt% to about 70 wt%, and the amount of amorphous carbon may be from about 20 wt% to about 40 wt%.

[0127] The amorphous carbon coating layer may have a thickness of about 5 nm to about 100 nm. The silicon particles (e.g., silicon primary particles) may be included (e.g., present) in silicon (e.g., elemental or by itself), a silicon alloy, or oxidized silicon (e.g., may exist in the form of silicon, a silicon alloy, or oxidized silicon). The oxidized silicon may be represented by SiO x (0 < x < 2). The atomic weight ratio of Si:O representing the degree of oxidation may be from about 99:1 to about 33:67. As used herein, the average particle size (D50) represents the diameter of the particles in which the cumulative volume in the particle size distribution corresponds to about 50 volume%.

[0128] In one or more embodiments, a Si-C composite may be included as a first negative electrode active material, and crystalline carbon may be included as a second negative electrode active material. A mixing ratio of the first negative electrode active material to the second negative electrode active material may be a weight ratio of about 1:99 to about 50:50. In another embodiment, the negative electrode active material may include a first negative electrode active material and a second negative electrode active material in a weight ratio of about 5:95 to about 20:80.

[0129] The negative electrode active material layer may further include a negative electrode active material and a binder, and may optionally further include a conductive material.

[0130] In the negative electrode active material layer, the amount of the negative electrode active material may be about 95wt% to about 99wt% based on the total weight of the negative electrode active material layer. In the negative electrode active material layer, the amount of the binder may be about 1wt% to about 5wt% based on the negative electrode active material layer. In the case where a conductive material is also included, the negative electrode active material may be included in an amount of about 90wt% to about 98wt%, the binder may be included in an amount of about 1wt% to about 5wt%, and the conductive material may be included in an amount of about 1wt% to about 5wt%.

[0131] The binder improves the binding properties between the negative electrode active material particles and between the negative electrode active material particles and the current collector. The binder may be a non-aqueous binder, an aqueous binder, or a combination thereof.

[0132] The non-aqueous binder can be ethylene propylene copolymer, polyacrylonitrile, polystyrene, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamideimide, polyimide, or a combination thereof (eg, one or more combinations).

[0133] The aqueous binder can be styrene-butadiene rubber, acrylated styrene-butadiene rubber, acrylonitrile-butadiene rubber, acrylic rubber, butyl rubber, fluororubber, ethylene oxide-containing polymers, polyvinyl pyrrolidone, polyepichlorohydrin, polyphosphazene, ethylene propylene diene copolymer, polyvinyl pyridine, chlorosulfonated polyethylene, latex, polyester resin, acrylic resin, phenolic resin, epoxy resin, polyvinyl alcohol, or a combination thereof (e.g., one or more combinations).

[0134] The negative electrode binder may include a cellulose compound. The negative electrode binder may include an aqueous binder and a cellulose compound. The cellulose compound includes one or more of carboxymethyl cellulose, hydroxypropyl methyl cellulose, methyl cellulose and their alkali metal salts. The alkali metal may be Na, K or Li. The cellulose compound may be used as a binder and may impart viscosity to act as a thickener. Therefore, the amount of the cellulose compound may be appropriately adjusted within the amount of the binder, and may be, for example, about 0.1 parts by weight to about 3 parts by weight based on 100 parts by weight of the negative electrode active material.

[0135] The conductive material is included to provide the electrode conductivity, and any electrically conductive material can be used as the conductive material unless it causes a chemical change. Examples of the conductive material can be: carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black and / or carbon fiber, etc.; metal-based materials of metal powder or metal fiber including copper, nickel, aluminum and / or silver, etc.; conductive polymers such as polyphenylene derivatives; or mixtures thereof.

[0136] The current collector may include one selected from the group consisting of copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, and combinations thereof, but is not limited thereto.

[0137] The electrolyte includes a non-aqueous organic solvent and a lithium salt.

[0138] The nonaqueous organic solvent serves as a medium for transporting ions participating in the electrochemical reaction of the battery.

[0139] The non-aqueous organic solvent may include a carbonate solvent, an ester solvent, an ether solvent, a ketone solvent, an alcohol solvent, or an aprotic solvent.

[0140] Carbonate solvents may include dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), ethyl methyl carbonate (MEC), ethylene carbonate (EC), propylene carbonate (PC) and / or butylene carbonate (BC) etc. Ester solvents may include methyl acetate, ethyl acetate, n-propyl acetate, dimethyl acetate, methyl propionate, ethyl propionate, decanoic acid lactone, mevalonate lactone and / or caprolactone etc. Ether solvents may include dibutyl ether, tetraethylene glycol dimethyl ether, diethylene glycol dimethyl ether, dimethoxyethane, 2-methyltetrahydrofuran and / or tetrahydrofuran etc. Ketone solvents may include cyclohexanone etc. Alcohol solvents may include ethanol and / or isopropanol, etc., and examples of aprotic solvents include nitriles (such as R-CN (wherein R is a C2 to C20 linear, branched or cyclic hydrocarbon, and may include a double bond, an aromatic ring or an ether bond)), amides (such as dimethylformamide), dioxolanes (such as 1,3-dioxolane) and / or sulfolane, etc.

[0141] The organic solvent may be used alone or in a mixture. If the organic solvent is used in a mixture (eg, when the organic solvent is used in a mixture), the mixing ratio may be controlled or selected according to the desired battery performance and may be well known to those skilled in the art.

[0142] The carbonate solvent may include a mixture having a cyclic carbonate and a chain carbonate. The cyclic carbonate and the chain carbonate are mixed together in a volume ratio of about 1:1 to about 1:9, and if the mixture is used as an electrolyte (e.g., when the mixture is used as an electrolyte), it may have enhanced performance.

[0143] The organic solvent may further include an aromatic hydrocarbon solvent and a carbonate solvent. The carbonate solvent and the aromatic hydrocarbon solvent may be mixed together in a volume ratio of about 1:1 to about 30:1.

[0144] The aromatic hydrocarbon organic solvent may be an aromatic hydrocarbon compound represented by Chemical Formula 20.

[0145] Chemical formula 20

[0146]

[0147] In Chemical Formula 20, R1 to R6 may all be independently the same or different, and are selected from hydrogen, halogen, C1 to C10 alkyl, halogenated alkyl, and combinations thereof.

[0148] Specific examples of aromatic hydrocarbon organic solvents can be selected from benzene, fluorobenzene, 1,2-difluorobenzene, 1,3-difluorobenzene, 1,4-difluorobenzene, 1,2,3-trifluorobenzene, 1,2,4-trifluorobenzene, chlorobenzene, 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene, 1,2,3-trichlorobenzene, 1,2,4-trichlorobenzene, iodobenzene, 1,2-diiodobenzene, 1,3-diiodobenzene, 1,4-diiodobenzene, 1,2,3-triiodobenzene, 1,2,4-triiodobenzene, toluene, 2,4-fluorotoluene, and 1,2-dichlorobenzene. 3-difluorotoluene, 2,4-difluorotoluene, 2,5-difluorotoluene, 2,3,4-trifluorotoluene, 2,3,5-trifluorotoluene, chlorotoluene, 2,3-dichlorotoluene, 2,4-dichlorotoluene, 2,5-dichlorotoluene, 2,3,4-trichlorotoluene, 2,3,5-trichlorotoluene, iodotoluene, 2,3-diiodotoluene, 2,4-diiodotoluene, 2,5-diiodotoluene, 2,3,4-triiodotoluene, 2,3,5-triiodotoluene, xylene, and one or more combinations thereof.

[0149] The electrolyte may further include ethyl vinyl carbonate, vinylene carbonate, and / or an ethylene carbonate-based compound represented by Chemical Formula 21 as an additive for improving cycle life.

[0150] Chemical formula 21

[0151]

[0152] In Chemical Formula 21, R7 and R8 may be independently the same or different, and may be independently hydrogen, halogen, cyano (CN), nitro (NO2) or fluorinated C1 to C5 alkyl, provided that at least one of R7 and R8 is halogen, cyano (CN), nitro (NO2) or fluorinated C1 to C5 alkyl, and R7 and R8 are not hydrogen at the same time (e.g., concurrently).

[0153] Examples of ethylene carbonate compounds may be difluoroethylene carbonate, chloroethylene carbonate, dichloroethylene carbonate, bromoethylene carbonate, dibromoethylene carbonate, nitroethylene carbonate, cyanoethylene carbonate, and / or fluoroethylene carbonate, etc. The amount of the additive for improving the cycle life characteristics may be utilized within an appropriate or suitable range.

[0154] The lithium salt dissolved in the organic solvent provides lithium ions to the battery, generally (e.g., substantially) operates the rechargeable lithium battery, and improves the transport of lithium ions between the positive electrode and the negative electrode. Examples of the lithium salt include at least one supporting salt selected from the group consisting of LiPF6, LiBF4, LiSbF6, LiAsF6, LiN(SO2C2F5)2, Li(CF3SO2)2N, LiN(SO3C2F5)2, Li(FSO2)2N (lithium bis(fluorosulfonyl)imide: LiFSI), LiC4F9SO3, LiClO4, LiAlO2, LiAlCl4, LiPO2F2, LiN(C x F 2x+1 SO2)(C y F 2y+1 SO2) (wherein x and y are natural numbers, for example, integers from about 1 to about 20), lithium difluoro(bis(oxalato)phosphate, LiCl, LiI, LiB(C2O4)2 (lithium bis(oxalato)borate: LiBOB), and lithium difluoro(oxalato)borate (LiDFOB). The concentration of the lithium salt may be about 0.1 M to about 2.0 M If the lithium salt is included in the described concentration range (eg, when the lithium salt is included in the described concentration range), the electrolyte may have excellent or suitable performance and lithium ion mobility due to optimal or suitable electrolyte conductivity and viscosity.

[0155] According to the type or kind of the rechargeable lithium battery, the separator may be disposed between the positive electrode and the negative electrode.

[0156] The separator may include a porous substrate and a coating layer including an organic material, an inorganic material, or a combination thereof on one or both (eg, opposing) surfaces of the porous substrate.

[0157] The porous substrate can be a polymer film formed by any one of polyolefins (such as polyethylene and / or polypropylene, etc.), polyesters (such as polyethylene terephthalate and / or polybutylene terephthalate, etc.), polyacetals, polyamides, polyimides, polycarbonates, polyether ketones, polyaryletherketones, polyetherimides, polyamideimides, polybenzimidazoles, polyethersulfones, polyphenylene oxides, cyclic olefin copolymers, polyphenylene sulfide, polyethylene naphthalate, glass fibers, TEFLON (tetrafluoroethylene) and polytetrafluoroethylene, or copolymers or mixtures of two or more thereof.

[0158] The porous substrate may have a thickness of about 1 μm to about 40 μm (eg, about 1 μm to about 30 μm, about 1 μm to about 20 μm, about 5 μm to about 15 μm, or about 10 μm to about 15 μm).

[0159] The organic material may include a (meth)acryl-based copolymer, the (meth)acryl-based copolymer including a first structural unit derived from (meth)acrylamide and a second structural unit, the second structural unit including at least one structural unit derived from (meth)acrylic acid or (meth)acrylate or a structural unit derived from (meth)acrylamide sulfonic acid or its salt.

[0160] The inorganic material may include inorganic particles selected from Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, GaO, ZnO, ZrO2, Y2O3, SrTiO3, BaTiO3, Mg(OH)2, boehmite, and combinations thereof, but is not limited thereto. The average particle size (D50) of the inorganic particles may be from about 1 nm to about 2000 nm (e.g., from about 100 nm to about 1000 nm or from about 100 nm to about 700 nm).

[0161] An organic material and an inorganic material may be mixed in one coating layer, or coating layers including an inorganic material may be stacked.

[0162] The coating layers may each have a thickness of about 0.5 μm to about 20 μm (eg, about 1 μm to about 10 μm or about 1 μm to about 5 μm).

[0163] The accompanying drawings are schematic diagrams of rechargeable lithium batteries according to one or more embodiments. The rechargeable lithium batteries according to some embodiments are shown as prismatic batteries, but are not limited thereto and may include batteries of various shapes (such as cylindrical batteries and / or pouch batteries, etc.).

[0164] Referring to the drawings, a rechargeable lithium battery 100 according to one or more embodiments may include an electrode assembly 40 manufactured by winding a separator 30 disposed between a positive electrode 10 and a negative electrode 20, and a case 50 accommodating the electrode assembly 40. An electrolyte may be impregnated in the positive electrode 10, the negative electrode 20, and the separator 30.

[0165] Terms such as "substantially", "about", and "approximately" are used as relative terms rather than as terms of degree, and are intended to take into account the inherent deviations of measured or calculated values ​​that one of ordinary skill in the art will recognize. They may include the stated value and an acceptable range of deviation as determined by one of ordinary skill in the art taking into account the limitations and errors associated with the measurement of that amount. For example, "about" may refer to one or more standard deviations, or ±30%, ±20%, ±10%, ±5% of the stated value.

[0166] The numerical ranges disclosed herein include and intend to disclose all sub-ranges of the same numerical precision. For example, a range of "1.0 to 10.0" includes all sub-ranges having a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0, such as 2.4 to 7.6. Therefore, the applicant reserves the right to amend this specification (including the claims) to explicitly list any sub-ranges included in the ranges explicitly listed herein.

[0167] Hereinafter, examples and comparative examples of the present disclosure are described. However, these examples should not be interpreted as limiting the scope of the present disclosure in any sense.

[0168] Example

[0169] Comparative Example 1

[0170] 98wt% LiNi 0.8 Co 0.1 Al 0.1 The O2 positive active material, 1 wt% of polyvinylidene fluoride binder and 1 wt% of Ketjen black conductive material were mixed in N-methylpyrrolidone solvent to prepare positive active material slurry. The positive active material slurry was coated on aluminum foil, dried and pressed to prepare a positive electrode.

[0171] 97 wt% of artificial graphite negative active material, 1 wt% of Ketjen black conductive material, 1 wt% of styrene-butadiene rubber binder and 1 wt% of carboxymethyl cellulose thickener were mixed in a distilled water solvent to prepare a negative active material slurry. The negative active material slurry was coated on a copper foil, dried and pressed to prepare a negative electrode.

[0172] 1.15 MLiPF6 was dissolved in a non-aqueous organic solvent in which ethylene carbonate, ethyl methyl carbonate and dimethyl carbonate were mixed in a volume % ratio of 2:4:4, and then vinylene carbonate (VC) and vinyl ethyl carbonate (VEC) were added thereto to prepare an electrolyte. The amount of vinylene carbonate was 1.5 wt % based on the total 100 wt % of the electrolyte, and the amount of vinyl ethyl carbonate was 0.5 wt % based on the total 100 wt % of the electrolyte.

[0173] A 18650 cylindrical rechargeable lithium battery cell was manufactured by general steps using a positive electrode, a negative electrode and an electrolyte.

[0174] Example 1

[0175] 97.95wt% LiNi 0.91 Co 0.06 Al 0.03 The O2 positive active material, 0.05 wt% of the additive of Chemical Formula 6, 1 wt% of the polyvinylidene fluoride binder and 1 wt% of the Ketjen black conductive material were mixed in an N-methylpyrrolidone solvent to prepare a positive active material slurry. The positive active material slurry was coated on an aluminum foil, dried and pressed to prepare a positive electrode.

[0176] Chemical formula 6

[0177]

[0178] Using the positive electrode and the negative electrode according to Comparative Example 1 and the electrolyte, a 18650 cylindrical rechargeable lithium battery cell was manufactured through general steps.

[0179] Example 2

[0180] 97.9wt% LiNi 0.91 Co 0.06 Al 0.03 The O2 positive active material, 0.1 wt% of the additive of Chemical Formula 6, 1 wt% of the polyvinylidene fluoride binder and 1 wt% of the Ketjen black conductive material were mixed in an N-methylpyrrolidone solvent to prepare a positive active material slurry. The positive active material slurry was coated on an aluminum foil, dried and pressed to prepare a positive electrode.

[0181] Using the positive electrode and the negative electrode according to Comparative Example 1 and the electrolyte, a 18650 cylindrical rechargeable lithium battery cell was manufactured through general steps.

[0182] Example 3

[0183] 97.7wt% LiNi 0.91 Co 0.06 Al 0.03The O2 positive active material, 0.3 wt% of the additive of Chemical Formula 6, 1 wt% of the polyvinylidene fluoride binder and 1 wt% of the Ketjen black conductive material were mixed in an N-methylpyrrolidone solvent to prepare a positive active material slurry. The positive active material slurry was coated on an aluminum foil, dried and pressed to prepare a positive electrode.

[0184] Using the positive electrode and the negative electrode according to Comparative Example 1 and the electrolyte, a 18650 cylindrical rechargeable lithium battery cell was manufactured through general steps.

[0185] Comparative Example 2

[0186] 97.5wt% LiNi 0.8 Co 0.1 Al 0.1 The O2 positive active material, 0.5 wt% of the additive of Chemical Formula 6, 1 wt% of the polyvinylidene fluoride binder and 1 wt% of the Ketjen black conductive material were mixed in an N-methylpyrrolidone solvent to prepare a positive active material slurry. The positive active material slurry was coated on an aluminum foil, dried and pressed to prepare a positive electrode.

[0187] Using the positive electrode and the negative electrode according to Comparative Example 1 and the electrolyte, a 18650 cylindrical rechargeable lithium battery cell was manufactured through general steps.

[0188] Comparison Example 3

[0189] 97.5 wt% of LiCoO2 positive active material, 0.5 wt% of the additive of Chemical Formula 6, 1 wt% of polyvinylidene fluoride binder and 1 wt% of Ketjen black conductive material were mixed in N-methylpyrrolidone solvent to prepare positive active material slurry. The positive active material slurry was coated on aluminum foil, dried and pressed to prepare a positive electrode.

[0190] Using the positive electrode and the negative electrode according to Comparative Example 1 and the electrolyte, a 18650 cylindrical rechargeable lithium battery cell was manufactured through general steps.

[0191] Example 4

[0192] 97.5wt% LiNi 0.91 Co 0.06 Al 0.03 The O2 positive active material, 0.5 wt% of the additive of Chemical Formula 6, 1 wt% of the polyvinylidene fluoride binder and 1 wt% of the Ketjen black conductive material were mixed in an N-methylpyrrolidone solvent to prepare a positive active material slurry. The positive active material slurry was coated on an aluminum foil, dried and pressed to prepare a positive electrode.

[0193] Using the positive electrode and the negative electrode according to Comparative Example 1 and the electrolyte, a 18650 cylindrical rechargeable lithium battery cell was manufactured through general steps.

[0194] Example 5

[0195] A positive electrode was prepared through the same steps as in Example 1, except that the additive of Chemical Formula 3 was used instead of the additive of Chemical Formula 6.

[0196] Chemical formula 3

[0197]

[0198] Using the positive electrode and the negative electrode according to Comparative Example 1 and the electrolyte, a 18650 cylindrical rechargeable lithium battery cell was manufactured through general steps.

[0199] Example 6

[0200] A positive electrode was prepared through the same steps as in Example 2, except that the additive of Chemical Formula 3 was used instead of the additive of Chemical Formula 6.

[0201] Using the positive electrode and the negative electrode according to Comparative Example 1 and the electrolyte, a 18650 cylindrical rechargeable lithium battery cell was manufactured through general steps.

[0202] Example 7

[0203] A positive electrode was prepared through the same steps as in Example 3, except that the additive of Chemical Formula 3 was used instead of the additive of Chemical Formula 6.

[0204] Using the positive electrode and the negative electrode according to Comparative Example 1 and the electrolyte, a 18650 cylindrical rechargeable lithium battery cell was manufactured through general steps.

[0205] Example 8

[0206] A positive electrode was prepared through the same steps as in Example 4, except that the additive of Chemical Formula 3 was used instead of the additive of Chemical Formula 6.

[0207] Using the positive electrode and the negative electrode according to Comparative Example 1 and the electrolyte, a 18650 cylindrical rechargeable lithium battery cell was manufactured through general steps.

[0208] Comparison Example 4

[0209] A positive electrode was prepared through the same steps as those in Comparative Example 2, except that the additive of Chemical Formula 3 was used instead of the additive of Chemical Formula 6.

[0210] Using the positive electrode and the negative electrode according to Comparative Example 1 and the electrolyte, a 18650 cylindrical rechargeable lithium battery cell was manufactured through general steps.

[0211] Experimental Example 1: Evaluation of Sulfur Content

[0212] The rechargeable lithium battery cells according to Comparative Examples 1 to Comparative Examples 4 and Examples 1 to Examples 8 were subjected to a formation charge and discharge at 0.1C. The positive electrode and the negative electrode were separated and collected from the battery cells subjected to formation charge and discharge, and then the amount of sulfur thereon was measured by a TOF-SIMS (time of flight secondary ion mass spectrometry) method, respectively. Among the results, the results of Comparative Examples 1 to Comparative Examples 3 and Examples 1 to Examples 4 are shown in Table 1, and the results of Comparative Examples 1 and Comparative Examples 4 and Examples 5 to Examples 8 are shown in Table 2.

[0213] Experimental Example 2: Evaluation of Capacity Retention Rate

[0214] The battery cell after formation charge and discharge in Experimental Example 1 was charged and discharged for 300 cycles at 45°C and 0.33C. The ratio of the 300th discharge capacity to the 1st discharge capacity was calculated. Among the results, the results of Comparative Examples 1 to 3 and Examples 1 to 4 are shown in Table 1 as capacity retention rates, and the results of Comparative Examples 1 and 4 and Examples 5 to 8 are shown in Table 2 as capacity retention rates.

[0215] Experimental Example 3: Evaluation of DC resistance DC-IR: DC internal resistance

[0216] The battery cell after formation charge and discharge in Experimental Example 1 was charged at 45°C under constant current / constant voltage conditions of 0.2C, 4.25V and 0.05C cutoff, paused for 10 minutes, and discharged at constant current under conditions of 0.33C and 2.80V cutoff, and paused for 10 minutes as a cycle, and the cycle was repeated 300 times. In each cycle, the voltage drop (V) was measured while the current flowed at 1C for 10 seconds at SOC50 (i.e., based on 100% of the entire battery charge capacity, charged to 50% of the charge capacity, which was discharged 50% in the discharge state). Based on these results, the DC internal resistance was calculated.

[0217] The percentage value (%) of the DC internal resistance (DC-IR) of the 300th cycle relative to the DC internal resistance of the 1st cycle was calculated. Among the results, the results of Comparative Examples 1 to 3 and Examples 1 to 4 are shown in Table 1 as DC-IR increase ratios, and the results of Comparative Examples 1 and 4 and Examples 5 to 8 are shown in Table 2 as DC-IR increase ratios.

[0218] Table 1

[0219]

[0220] As shown in Table 1, the rechargeable lithium battery cells of Examples 1 to 4 (wherein the amount of sulfur included in the positive electrode is twice or more the amount of sulfur included in the negative electrode) (i.e., by adding the additive of Chemical Formula 6 to the positive electrode) exhibited a higher capacity retention rate and a lower DC-IR increase ratio as compared to Comparative Examples 1 to 3.

[0221] Table 2

[0222]

[0223] As shown in Table 2, the rechargeable lithium battery cells of Examples 5 to 8 (wherein the amount of sulfur included in the positive electrode is twice or more the amount of sulfur included in the negative electrode) (i.e., by adding the additive of Chemical Formula 3 to the positive electrode) exhibited a higher capacity retention rate and a lower DC-IR increase ratio as compared to Comparative Examples 1 and 4.

[0224] Experimental Example 4 Evaluation of storage at high temperature

[0225] The battery cell after the formation charge and discharge in Experimental Example 1 was charged at 4.25V to measure the charge capacity. The battery cell was stored at 60°C for 30 days. After storage for 30 days, the battery cell was charged and discharged once at 0.33C to measure the ratio of the charge capacity after storage for 30 days to the charge capacity before storage. Among the results, the results of Comparative Examples 1 to 3 and Examples 1 to 4 are shown in Table 3 as the storage capacity after allowing to stand, and the results of Comparative Examples 1 and 4 and Examples 5 to 8 are shown in Table 4 as the storage capacity after allowing to stand.

[0226] The battery cells after formation charge and discharge in Experimental Example 1 were discharged at a constant current of 10A for 10 seconds, at a constant current of 1A for 10 seconds, and at a constant current of 10A for 4 seconds in a fully charged state (SOC100, state of charge = 100%) to measure the voltage drop. Based on these results, the direct current (DC) resistance on the first day was measured. Thereafter, the battery cells were stored at 60°C for 30 days to measure the voltage drop. Based on these results, the DC resistance after storage for 30 days was calculated. The percentage value (%) of the DC internal resistance (DC-IR) after 30 days relative to the DC internal resistance on the first day was calculated.

[0227] Among the results, the results of Comparative Examples 1 to 3 and Examples 1 to 4 are shown in Table 3 as storage DC-IR increase ratios, and the results of Comparative Examples 1 and 4 and Examples 5 to 8 are shown in Table 4 as storage DC-IR increase ratios.

[0228] Table 3

[0229]

[0230] As shown in Table 3, the rechargeable lithium battery cells of Examples 1 to 4 (wherein the amount of sulfur included in the positive electrode is twice or more the amount of sulfur included in the negative electrode) (i.e., by adding the additive of Chemical Formula 6 to the positive electrode) exhibit excellent or suitable high temperature storage characteristics as compared to Comparative Examples 1 to 3.

[0231] Table 4

[0232]

[0233] As shown in Table 4, the rechargeable lithium battery cells of Examples 5 to 8 (wherein the amount of sulfur included in the positive electrode is twice or more the amount of sulfur included in the negative electrode) (i.e., by adding the additive of Chemical Formula 3 to the positive electrode) exhibit excellent or suitable high temperature storage characteristics compared to Comparative Examples 1 and 4. The storage DC-IR increase ratio of the rechargeable lithium battery cells according to Examples 5 to 8 is shown to be lower than that of Comparative Examples 1 and 4. The charge capacity of the rechargeable lithium battery after storage at 60°C for 30 days is at least 87% of the charge capacity of the rechargeable lithium battery before storage.

[0234] The battery management system (BMS) device and / or any other related device or component according to the embodiments of the present disclosure described herein can be implemented using any suitable hardware, firmware (e.g., a dedicated integrated circuit), software, or a combination of software, firmware, and hardware. For example, the various components of the device can be formed on an integrated circuit (IC) chip or on a separate IC chip. In addition, the various components of the device can be implemented on a flexible printed circuit film, a tape carrier package (TCP), a printed circuit board (PCB), or formed on a substrate. In addition, the various components of the device can be processes or threads that run on one or more processors in one or more computing devices to execute computer program instructions and interact with other system components to perform the various functions described herein. The computer program instructions are stored in a memory, which can be implemented in a computing device using a standard memory device (such as a random access memory (RAM) as an example). The computer program instructions can also be stored in other non-temporary computer-readable media (such as a CD-ROM, a flash drive, etc. as an example). In addition, it should be recognized by those skilled in the art that the functions of various computing devices can be combined or integrated into a single computing device without departing from the scope of the present disclosure, or the functions of a particular computing device can be distributed across one or more other computing devices.

[0235] Although the present disclosure has been described in conjunction with what are presently considered to be practical example embodiments, it will be understood that the present disclosure is not limited to the disclosed embodiments, but on the contrary, is intended to cover one or more suitable modifications and equivalent arrangements included within the spirit and scope of the appended claims and their equivalents. Therefore, the foregoing embodiments should be understood as examples, and not to limit the present disclosure in any way.

Claims

1. A rechargeable lithium battery, comprising: A positive electrode, comprising a positive active material and a certain amount of sulfur; A negative electrode, comprising a negative electrode active material and a certain amount of sulfur; as well as Non-aqueous electrolytes, wherein the amount of sulfur included in the positive electrode is at least twice the amount of sulfur included in the negative electrode.

2. The rechargeable lithium battery according to claim 1, wherein The amount of sulfur included in the positive electrode is two to five times the amount of sulfur included in the negative electrode.

3. The rechargeable lithium battery according to claim 1, wherein The amount of sulfur included in the positive electrode is about 0.01 wt % to about 0.7 wt % based on the total 100 wt % of the rechargeable lithium battery.

4. The rechargeable lithium battery according to claim 1, wherein The amount of sulfur included in the positive electrode is about 0.03 wt % to about 0.7 wt % based on the total 100 wt % of the rechargeable lithium battery.

5. The rechargeable lithium battery according to claim 1, wherein The amount of sulfur included in the negative electrode is greater than 0 wt % and at most 0.33 wt % based on the total 100 wt % of the rechargeable lithium battery.

6. The rechargeable lithium battery according to claim 1, wherein: The amount of sulfur included in the negative electrode is about 0.01 wt % to about 0.33 wt % based on 100 wt % of the total amount of the rechargeable lithium battery.

7. The rechargeable lithium battery according to claim 1, wherein: The positive electrode active material is a compound represented by Chemical Formula 1: Chemical formula 1 Li a1 Ni x1 Co y1 A z1 O2, and in, 0.9≤a1≤1.1, 0.88≤x1≤0.98, 0.01≤y1≤0.11, 0.01≤z1≤0.11, x1+y1+z1=1, and A is Mn or Al.

8. The rechargeable lithium battery according to claim 1, wherein: The rechargeable lithium battery is a battery that undergoes formation charge and discharge.

9. The rechargeable lithium battery according to claim 8, wherein: The formation charge and discharge is performed one to three times at 0.1C to 0.3C.

10. The rechargeable lithium battery according to claim 1, wherein: The positive electrode includes a positive active material layer including a positive active material layer composition including the positive active material and an additive represented by Chemical Formula 2 or one or more additives represented by one or more selected from Chemical Formulas 3 to 5: Chemical formula 2 and in, A1, A2, A3 and A4 are independently selected from the following: a covalent bond; a C1 to C5 alkylene group substituted or unsubstituted by a substituent; a carbonyl group; and a sulfinyl group, provided that A1 and A2 are not covalent bonds at the same time, and A3 and A4 are not covalent bonds at the same time; Chemical formula 3 Chemical formula 4 Chemical formula 5 11. The rechargeable lithium battery according to claim 10, wherein: The additive represented by Chemical Formula 2 is represented by Chemical Formula 2a or Chemical Formula 2b: Chemical formula 2a Chemical formula 2b and in, Z1, Z2, Z3, Z4, Z5 and Z6 are independently: -C(E1)(E2)-; carbonyl; or sulfinyl, and E1 and E2 are each independently selected from the following: hydrogen; halogen; halogen-substituted or unsubstituted C1 to C20 alkyl; halogen-substituted or unsubstituted C2 to C20 alkenyl; halogen-substituted or unsubstituted C2 to C20 alkynyl; halogen-substituted or unsubstituted C3 to C20 cycloalkenyl; halogen-substituted or unsubstituted C3 to C20 heterocyclyl; halogen-substituted or unsubstituted C6 to C40 aryl; and halogen-substituted or unsubstituted C2 to C40 heteroaryl.

12. The rechargeable lithium battery according to claim 10, wherein: The additive represented by Chemical Formula 2 is at least one compound represented by at least one selected from Chemical Formulas 6 to 9: Chemical formula 6 Chemical formula 7 Chemical formula 8 Chemical formula 9 13. The rechargeable lithium battery according to claim 11, wherein: The additive represented by Chemical Formula 2 is a compound represented by Chemical Formula 6.

14. The rechargeable lithium battery according to claim 10, wherein: The amount of the additive represented by Chemical Formula 2 or the one or more additives represented by one or more selected from Chemical Formulas 3 to 5 is 0.05 wt % to 2.1 wt % based on 100 wt % of the total positive active material layer composition.

15. The rechargeable lithium battery according to claim 1, wherein: The charge capacity of the rechargeable lithium battery after storage at 60° C. for 30 days is at least 87% of the charge capacity of the rechargeable lithium battery before storage.

16. A method of forming a rechargeable lithium battery, the method comprising the steps of: adding an additive represented by Chemical Formula 2 or one or more additives represented by one or more selected from Chemical Formulas 3 to 5 to a positive electrode active material layer composition for a positive electrode; Chemical formula 2 and in, A1, A2, A3 and A4 are independently selected from: a covalent bond; a C1 to C5 alkylene group substituted or unsubstituted by a substituent; a carbonyl group; or a sulfinyl group, provided that A1 and A2 are not covalent bonds at the same time, and A3 and A4 are not covalent bonds at the same time; Chemical formula 3 Chemical formula 4 Chemical formula 5 as well as The positive electrode in the battery is subjected to formation charge and discharge at 0.1C to 0.3C one to three times to form the rechargeable lithium battery.

17. The method according to claim 16, wherein: The additive represented by Chemical Formula 2 is represented by Chemical Formula 2a or Chemical Formula 2b: Chemical formula 2a Chemical formula 2b and in, Z1, Z2, Z3, Z4, Z5 and Z6 are independently: -C(E1)(E2)-; carbonyl; or sulfinyl, and E1 and E2 are each independently selected from the following: hydrogen; halogen; halogen-substituted or unsubstituted C1 to C20 alkyl; halogen-substituted or unsubstituted C2 to C20 alkenyl; halogen-substituted or unsubstituted C2 to C20 alkynyl; halogen-substituted or unsubstituted C3 to C20 cycloalkenyl; halogen-substituted or unsubstituted C3 to C20 heterocyclyl; halogen-substituted or unsubstituted C6 to C40 aryl; and halogen-substituted or unsubstituted C2 to C40 heteroaryl.

18. The method according to claim 16, wherein: The additive represented by Chemical Formula 2 is at least one compound represented by at least one selected from Chemical Formulas 6 to 9: Chemical formula 6 Chemical formula 7 Chemical formula 8 Chemical formula 9 19. The method according to claim 16, wherein: The additive represented by Chemical Formula 2 is a compound represented by Chemical Formula 6.

20. The method according to claim 16, wherein: The amount of the additive represented by Chemical Formula 2 or the one or more additives represented by one or more selected from Chemical Formulas 3 to 5 is 0.05 wt % to 2.1 wt % based on 100 wt % of the total positive active material layer composition.

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