Cyclic carbonate-based compound, electrolyte for rechargeable lithium battery, and rechargeable lithium battery including same

Abstract

The present application relates to a cyclic carbonate-based compound, an electrolyte for a rechargeable lithium battery, and a rechargeable lithium battery including the electrolyte. The rechargeable lithium battery includes: a positive electrode including a positive electrode active material; a negative electrode including a negative electrode active material; and an electrolyte for a rechargeable lithium battery. The electrolyte comprises a non-aqueous organic solvent, a lithium salt and an additive. The additive comprises a cyclic carbonate compound, and the cyclic carbonate compound comprises an azide-containing group.

Description

[0001] Cross-references to related applications

[0002] This application claims priority and benefit to Korean Patent Application No. 10-2024-0108003, filed with the Korean Intellectual Property Office on August 13, 2024, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] One or more aspects of embodiments of this disclosure relate to cyclic carbonate compounds, electrolytes for rechargeable lithium batteries, and rechargeable lithium batteries comprising the electrolytes. Background Technology

[0004] With the recent increase in the use of battery-powered electronic devices (such as mobile phones and / or laptops) and / or electric vehicles, the demand for rechargeable batteries with high energy density and high capacity has also increased. In view of this growing demand, research into improving the performance of rechargeable lithium batteries has been ongoing.

[0005] A rechargeable lithium battery includes a positive electrode, a negative electrode, and an electrolyte, wherein the positive and negative electrodes include active materials capable of intercalating and deintercalating (lithium ions). If lithium ions are intercalated and deintercalated, the rechargeable lithium battery generates electrical energy through oxidation and reduction reactions.

[0006] Lithium salts dissolved in non-aqueous organic solvents can be used as electrolytes in rechargeable lithium-ion batteries. The characteristics of rechargeable lithium-ion batteries are manifested (e.g., affected) through complex reactions between the positive electrode and the electrolyte, and between the negative electrode and the electrolyte. Accordingly, the use of a suitable or appropriate electrolyte is an important variable for improving rechargeable lithium-ion batteries. Summary of the Invention

[0007] One or more aspects of embodiments of this disclosure relate to additives that have an enhanced (e.g., superior or appropriate) effect on improving battery performance at (relatively) high voltage and (relatively) high temperature.

[0008] One or more aspects of embodiments of this disclosure relate to rechargeable lithium batteries that have enhanced (e.g., superior or suitable) performance at (relatively) high voltage and (relatively) high temperature. Further aspects will be set forth in part in the description which follows and will be apparent in part from the description, or may be learned by practicing the embodiments presented in this disclosure.

[0009] According to one or more embodiments of this disclosure, the electrolyte for a rechargeable lithium battery may include a non-aqueous organic solvent, a lithium salt, and additives. The additives may include cyclic carbonate compounds comprising azide groups.

[0010] According to one or more embodiments of this disclosure, cyclic carbonate compounds may be represented by chemical formula 1 or chemical formula 2.

[0011] Chemical Formula 1

[0012]

[0013] In chemical formula 1,

[0014] The subscript n can be an integer from 2 to 5, for example, 2, 3, 4 or 5.

[0015] R1 can be hydrogen, substituted or unsubstituted C1-C10 alkyl, substituted or unsubstituted C2-C10 alkenyl, substituted or unsubstituted C2-C10 alkynyl, or containing an azide group, each independently.

[0016] R1 can be independently the same or different from each other, and

[0017] At least one of R1 may be an azide group.

[0018] Chemical formula 2

[0019]

[0020] In chemical formula 2,

[0021] The subscript m can be an integer from 0 to 3, for example, 0, 1, 2 or 3.

[0022] The subscript z can be an integer from 0 to 3, for example, 0, 1, 2 or 3.

[0023] The sum of m and z can be an integer equal to or less than 3.

[0024] R2 can be hydrogen, substituted or unsubstituted C1-C10 alkyl, substituted or unsubstituted C2-C10 alkenyl, substituted or unsubstituted C2-C10 alkynyl, or containing an azide group, each independently.

[0025] R2 values ​​can be independently the same or different from each other, and

[0026] At least one of R2 may be an azide group.

[0027] According to one or more embodiments of this disclosure, a rechargeable lithium battery may include: a positive electrode including a positive electrode active material; a negative electrode including a negative electrode active material; and the aforementioned electrolyte for a rechargeable lithium battery. Attached Figure Description

[0028] These and / or other aspects will become apparent and more readily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0029] Figure 1 A simplified conceptual diagram illustrating a rechargeable lithium battery according to one or more embodiments of the present disclosure is provided.

[0030] Figures 2-5 Simplified diagrams illustrating one or more embodiments of a rechargeable lithium battery according to this disclosure are provided, wherein... Figure 2 A cylindrical battery is shown. Figure 3 A prismatic battery is shown, and Figure 4 and Figure 5 Showing pouch-type (types) of batteries;

[0031] Figure 6 The explanation illustrates the compound according to Synthesis Example 1. 1 A graph of H-NMR spectral results. Detailed Implementation

[0032] This disclosure will now be described in more detail with reference to the accompanying drawings. However, it should be noted that this disclosure is not limited to the exemplary embodiments described below, and may be implemented in one or more suitable forms. Rather, exemplary embodiments are provided only to describe this disclosure and to enable those skilled in the art to fully understand its scope.

[0033] In this description, it will be understood that if (e.g., when) an element is referred to as being on another element, then the element may be directly on the other element, or there may be an intervening element between them. In contrast, if an element is referred to as being directly on another element, then there may be no intervening element between them. In the accompanying drawings, for the purpose of explaining the technical content, some dimensions (e.g., thickness) of some components have been enlarged. Throughout the specification, the same reference numerals refer to the same elements, and their repeated descriptions are not required.

[0034] Unless otherwise specifically stated in this description, singular expressions may include plural expressions. Additionally, unless otherwise specifically stated, the phrase "A or B" may indicate "A but not B," "B but not A," and "A and B." The terms "comprises / includes" and / or "comprising / including" as used in this description do not exclude the presence or addition of one or more other components. Furthermore, the terms "comprise(s) / comprising," "include(s) / including," "have / has / having," or similar terms include or support the terms "consisting of," and "substantially consisting of," indicating the presence of the described feature, integer, step, operation, element, component, and / or group thereof, while other features, integers, steps, operations, elements, components, and / or groups thereof are absent or substantially absent.

[0035] In this description, the term "combination thereof" may refer to a mixture, stack, complex, copolymer, alloy, blend, or reaction product of the components.

[0036] It will be understood that although the terms "first," "second," etc., may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another. Therefore, without departing from the teachings of the invention, a first element may be referred to as a second element. Similarly, a second element may be referred to as a first element.

[0037] The terms “use,” “using,” and “used” as used herein can be considered synonymous with the terms “utilize,” “utilizing,” and “utilized,” respectively.

[0038] Expressions such as “at least one of…”, “one of…”, and “selected from…” used herein, when placed before or after a list of elements, modify the entire list of elements and do not modify any individual element in the list. For example, the expressions “at least one of a, b, and c” and “at least one of a, b, and / or c” can indicate only a, only b, only c, both a and b (e.g., simultaneously), both a and c (e.g., simultaneously), both b and c (e.g., simultaneously), all of a, b, and c, or variations thereof.

[0039] As used herein, the term “and / or” includes any and all combinations of one or more of the associated enumerated items.

[0040] Furthermore, when describing embodiments of this disclosure, the word "may" refers to "one or more embodiments of this disclosure".

[0041] Unless otherwise specifically defined in this description, particle size may be the average particle size. Additionally, particle size indicates the average particle size (D) that constitutes approximately 50% of the cumulative volume of the particle size distribution. 50 Average particle size (D) 50 The average particle size (D) can be measured by any suitable method in the art, for example, by a particle size analyzer, transmission electron microscopy (TEM) images, and / or scanning electron microscopy (SEM) images. In one or more embodiments, a dynamic light scattering measurement device is used for data analysis, counting the number of particles in each particle size range, from which the average particle size (D) can be calculated. 50 The value. In some implementations, laser scattering methods can be used to measure the average particle size (D). 50 In the laser scattering method, target particles are distributed in a dispersion solvent. A laser scattering particle size analyzer (e.g., the MT3000 from Microtrac) is introduced and irradiated with ultrasound at 28 kHz at a power of 60 W. The average particle size (D) is then calculated using the analyzer against a 50% particle size distribution standard. 50 In this specification, when the particles are spherical, "diameter" indicates the particle size, and when the particles are non-spherical, "diameter" indicates the length of the major axis.

[0042] For ease of description, spatial relative terms (such as "below," "under," "down," "above," "upper," "bottom," "top," etc.) may be used herein to describe the relationship between one element or feature illustrated in the accompanying drawings and another element or feature. It will be understood that spatial relative terms are intended to encompass different orientations of the device in use or operation other than those illustrated in the accompanying drawings; for example, if the device in the accompanying drawings is flipped, an element described as "below" or "under" other elements or features will be oriented "above" or "on top" of other elements or features. Therefore, the term "below" can encompass both above and below orientations. The device may be oriented in other ways (rotated 90 degrees or otherwise), and the spatial relative descriptors used herein should be interpreted accordingly.

[0043] The terms “substantially,” “about,” and similar terms used herein are used as terms of approximation and not as terms of degree, and are intended to describe the inherent biases in measured or calculated values ​​that would be recognized by one of ordinary skill in the art. The terms “about” or “approximation” as used herein include stated values ​​and mean within an acceptable range of deviation for a particular value, determined by one of ordinary skill in the art taking into account the measurement in question and the errors associated with the measurement of the particular quantity (i.e., limitations of the measurement system). For example, “about” may mean within one or more standard deviations, or within ±30%, ±20%, ±10%, or ±5% of the stated value.

[0044] Any numerical range set forth herein is intended to include all subranges of the same numerical precision falling within the set forth range. For example, the range “1.0 to 10.0” is intended to include (and inclusive) the stated minimum value of 1.0 and the stated maximum value of 10.0, that is, all subranges having a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0, such as, for example, 2.4 to 7.6. Any maximum numerical limit set forth herein is intended to include all lower numerical limits falling within it, and any minimum numerical limit set forth in this specification is intended to include all higher numerical limits falling within it. Accordingly, the applicant reserves the right to amend this specification (including the claims) to expressly set forth any subranges falling within the range expressly set forth herein.

[0045] Any related electronic device, means of manufacture, or component of the embodiments of this disclosure described herein may be implemented using any suitable hardware, firmware (e.g., application-specific integrated circuit), software, or a combination of software, firmware, and hardware. For example, various components of the device may be formed on an integrated circuit (IC) chip or on a separate IC chip. Furthermore, various components of the device may be implemented on a flexible printed circuit film, a tape-on-a-package (TCP), or a printed circuit board (PCB), or formed on a substrate. Additionally, various components of the device may be processes or threads that run on one or more processors in one or more computing devices, execute computer program instructions, and interact with other system components to perform the various functions described herein. The computer program instructions are stored in memory, which may be implemented using standard memory devices in the computing device, such as, for example, random access memory (RAM). The computer program instructions may also be stored in other non-transitory computer-readable media, such as, for example, a CD-ROM or a flash drive. Moreover, those skilled in the art will recognize that, without departing from the scope of embodiments of this disclosure, the functionality of various computing devices may be combined or integrated into a single computing device, or the functionality of a dedicated computing device may be distributed across one or more other computing devices.

[0046] Considering the entirety of this disclosure, those skilled in the art will recognize that each suitable feature of the various embodiments of this disclosure may be combined in part or in whole, or combined with one another, and may be technically interlocked and operated in a variety of suitable ways, and that each embodiment may be implemented independently of one another or in combination with one another in any suitable way, unless otherwise stated or implied.

[0047] In this description, unless otherwise specified separately, the term "substitution" may refer to a substituent or at least one hydrogen atom of a compound being substituted with: deuterium, halogen, hydroxyl, amino, C1-C30 amino, nitro, C1-C40 silyl, C1-C30 alkyl, C1-C10 alkylsilyl, C6-C30 arylsilyl, C3-C30 cycloalkyl, C3-C30 heterocycloalkyl, C6-C30 aryl, C2-C30 heteroaryl, C1-C20 alkoxy, C1-C10 fluoroalkyl, cyano, and / or combinations thereof (e.g., any suitable combination thereof).

[0048] More specifically, the term "substitution" may refer to at least one hydrogen atom of a substituent or compound being substituted with: deuterium, halogroup, C1-C30 alkyl, C1-C10 alkylsilyl, C6-C30 arylsilyl, C3-C30 cycloalkyl, C3-C30 heterocycloalkyl, C6-C30 aryl, C2-C30 heteroaryl, C1-C10 fluoroalkyl, or cyano. For example, the term "substitution" may refer to at least one hydrogen atom of a substituent or compound being substituted with: deuterium, halogroup, C1-C20 alkyl, C6-C30 aryl, C1-C10 fluoroalkyl, or cyano. In one or more embodiments, the term "substitution" may refer to at least one hydrogen atom of a substituent or compound being substituted with: deuterium, halogroup, C1-C5 alkyl, C6-C18 aryl, C1-C5 fluoroalkyl, or cyano. For example, the term "substitution" can refer to the substitution of at least one hydrogen atom of a substituent or compound by the following: deuterium, cyano, halo, methyl, ethyl, propyl, butyl, phenyl, biphenyl, terphenyl, trifluoromethyl, or naphthyl.

[0049] Figure 1 A simplified conceptual diagram illustrating a rechargeable lithium battery according to one or more embodiments of the present disclosure is provided. References Figure 1 A rechargeable lithium battery may include a positive electrode 10, a negative electrode 20, a separator 30, and an electrolyte ELL.

[0050] The positive electrode 10 and the negative electrode 20 may be spaced apart and / or separated from each other (e.g., spaced apart and / or separated) by a diaphragm 30. The diaphragm 30 may be disposed between the positive electrode 10 and the negative electrode 20. The positive electrode 10, the negative electrode 20, and the diaphragm 30 may be in contact with the electrolyte ELL. The positive electrode 10, the negative electrode 20, and the diaphragm 30 may be immersed in the electrolyte ELL.

[0051] The electrolyte ELL serves as a medium for transferring lithium ions between the positive electrode 10 and the negative electrode 20. In the electrolyte ELL, lithium ions can move through the separator 30 toward one of the positive electrode 10 and the negative electrode 20.

[0052] Positive electrode 10

[0053] The positive electrode 10 for a rechargeable lithium battery may include a positive electrode current collector COL1 and a positive electrode active material layer AML1 formed on the positive electrode current collector COL1. The positive electrode active material layer AML1 may include a positive electrode active material and further include a binder and / or a conductive material (e.g., an electronic conductor).

[0054] The amount of positive electrode active material relative to 100 wt% of the positive electrode active material layer AML1 can be about 90 wt% to about 99 wt%. The amount of each of the binder and conductive material relative to 100 wt% of the positive electrode active material layer AML1 can be about 0.5 wt% to about 5 wt%.

[0055] The binder can be used to improve the adhesion between the positive electrode active material particles and also to improve the adhesion between the positive electrode active material and the positive electrode current collector COL1. The binder may include, for example, polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene oxide-containing polymers, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, epoxy resin, (meth)acrylate resin, polyester resin and / or nylon, but this disclosure is not limited thereto.

[0056] Conductive materials can be used to provide electrode conductivity (e.g., to improve electrode conductivity). As a conductive material, any suitable conductive material that will not cause undesirable chemical changes in the battery can be used. Conductive materials may include: for example, carbon-based materials (such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fibers, carbon nanofibers, and / or carbon nanotubes); metal powders and / or metal fibers containing one or more of copper, nickel, aluminum, and silver; conductive polymers (such as polyphenylene derivatives); and / or mixtures thereof (e.g., any suitable mixture).

[0057] Aluminum (Al) foil can be used as the positive electrode current collector COL1, but this disclosure is not limited thereto.

[0058] Positive electrode active material

[0059] The positive electrode active material in the positive electrode active material layer AML1 may include compounds (e.g., lithiation intercalation compounds) that can reversibly insert and extract lithium (e.g., lithium ions). For example, the positive electrode active material may include at least one type of composite oxide comprising lithium and a metal selected from cobalt, manganese, nickel and / or combinations thereof (e.g., any suitable combination thereof).

[0060] Composite oxides may include lithium transition metal composite oxides, such as lithium nickel oxides, lithium cobalt oxides, lithium manganese oxides, lithium iron phosphate compounds, cobalt-free nickel manganese oxides, and / or combinations thereof (e.g., any suitable combination thereof).

[0061] For example, the positive electrode active material may include a compound represented (e.g., expressed) by one of the following chemical formulas (e.g., selected from at least one of the following): Li a A 1-b X b O 2-c D c (where 0.90≤a≤1.8, 0≤b≤0.5, and 0≤c≤0.05); Li a Mn 2-b X b O 4-c D c (where 0.90≤a≤1.8, 0≤b≤0.5, and 0≤c≤0.05); Li a Ni 1-b- c Co b X c O 2-α D α (where 0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, and 0<α<2); Li a Ni 1-b-c Mn b X c O 2-α D α (where 0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, and 0<α<2); Li a Ni b Co c L 1 d G e O2 (where 0.90 ≤ a ≤ 1.8, 0 ≤ b ≤ 0.9, 0 ≤ c ≤ 0.5, 0 ≤ d ≤ 0.5, and 0 ≤ e ≤ 0.1); Li a NiG b O2 (where 0.90 ≤ a ≤ 1.8 and 0.001 ≤ b ≤ 0.1); Li a CoGb O2 (where 0.90 ≤ a ≤ 1.8 and 0.001 ≤ b ≤ 0.1); Li a Mn 1-b G b O2 (where 0.90 ≤ a ≤ 1.8 and 0.001 ≤ b ≤ 0.1); Li a Mn2G b O4 (where 0.90 ≤ a ≤ 1.8 and 0.001 ≤ b ≤ 0.1); Li a Mn 1-g G g PO4 (where 0.90 ≤ a ≤ 1.8 and 0 ≤ g ≤ 0.5); Li (3-f) Fe2(PO4)3 (where 0≤f≤2); Li a FePO4 (where 0.90≤a≤1.8).

[0062] In the above chemical formulas, A can be Ni, Co, Mn and / or combinations thereof (e.g., any suitable combination thereof), X can be Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, rare earth elements and / or combinations thereof (e.g., any suitable combination thereof), D can be O, F, S, P and / or combinations thereof (e.g., any suitable combination thereof), G can be Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V and / or combinations thereof (e.g., any suitable combination thereof), and L 1 It can be Mn, Al and / or combinations thereof (e.g., any suitable combination thereof).

[0063] For example, relative to 100 mol% of lithium-free metal (e.g., metal excluding lithium) in a lithium transition metal complex oxide, the positive electrode active material can be a high-nickel positive electrode active material with a nickel content equal to or greater than about 80 mol%, equal to or greater than about 85 mol%, equal to or greater than about 90 mol%, equal to or greater than about 91 mol%, or equal to or greater than about 94 mol% and equal to or less than about 99 mol%. High-nickel positive electrode active materials can appropriately achieve high capacity, and are therefore suitable for high-capacity and high-density rechargeable lithium batteries. For example, the positive electrode active material can be a high-nickel material with a nickel content ranging from 80 mol% to 99 mol% (excluding lithium). This high-nickel composition can achieve high capacity, making it suitable for high-capacity and high-density rechargeable lithium batteries.

[0064] negative electrode 20

[0065] The negative electrode 20 for a rechargeable lithium battery may include a negative electrode current collector COL2 and a negative electrode active material layer AML2 located on the negative electrode current collector COL2. The negative electrode active material layer AML2 may include a negative electrode active material and may further include a binder and / or a conductive material (e.g., an electronic conductor).

[0066] For example, relative to 100 wt% of the negative electrode active material layer AML2, the negative electrode active material layer AML2 may include about 90 wt% to about 99.5 wt% of the negative electrode active material, about 0.5 wt% to about 5 wt% of the binder, and about 0 wt% to about 5 wt% of the conductive material.

[0067] The binder can be used to improve the adhesion between the negative electrode active material particles and also to improve the adhesion between the negative electrode active material and the negative electrode current collector COL2. The binder may include non-aqueous binders, aqueous binders, dry binders and / or combinations thereof (e.g., any suitable combination thereof).

[0068] Non-aqueous adhesives may include polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene-propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamide-imide, polyimide and / or combinations thereof (e.g., any suitable combination thereof).

[0069] Waterborne adhesives may include styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluoroelastomers, polyethylene oxide, polyvinylpyrrolidone, polyepoxychloropropane, polyphosphazene, poly(meth)acrylonitrile, ethylene propylene diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acrylic resin, phenolic resin, epoxy resin, polyvinyl alcohol, and / or combinations thereof (e.g., any suitable combination thereof).

[0070] When the aqueous binder is used as a negative electrode binder, it may further include a cellulose compound as a thickener capable of providing viscosity. The cellulose compound may include one or more selected from carboxymethyl cellulose, hydroxypropyl methyl cellulose, methyl cellulose, and their alkali metal salts. The alkali metal may include Na, K, and / or Li.

[0071] Dry adhesives may include fibrous polymeric materials, such as polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide and / or combinations thereof (e.g., any suitable combination thereof).

[0072] The conductive material can be used to provide the electrode with appropriate conductivity (e.g., to improve electrode conductivity), and as the conductive material (e.g., an electronic conductor), any suitable conductive material that does not cause undesirable chemical changes in the battery can be used. For example, the conductive material can include: carbonaceous materials (such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fiber, carbon nanofiber, and / or carbon nanotube); metal powders and / or metal fibers including one or more selected from copper, nickel, aluminum, and silver; conductive polymers (such as polyphenylene derivatives); and / or their (e.g., any suitable) mixtures.

[0073] The negative electrode current collector COL2 can include copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, and / or their combination (e.g., any suitable combination thereof).

[0074] Negative electrode active material

[0075] The negative electrode active material in the negative electrode active material layer AML2 can include materials that can reversibly intercalate and deintercalate lithium ions, lithium metal, lithium metal alloys, materials that can be doped and dedoped with lithium, and / or transition metal oxides.

[0076] Materials that can reversibly intercalate and deintercalate lithium ions can include carbonaceous negative electrode active materials, e.g., crystalline carbon, amorphous carbon, and / or their combination (e.g., any suitable combination thereof). For example, crystalline carbon can include graphite (such as amorphous (e.g., having a random shape), flaky, lamellar, spherical, and / or fibrous natural graphite and / or artificial graphite), and amorphous carbon can include soft carbon, hard carbon, mesophase pitch carbon, or calcined coke.

[0077] Lithium metal alloys can include alloys of lithium and metals selected from Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, and Sn.

[0078] Materials that can be doped and dedoped with lithium can include Si-based negative electrode active materials and / or Sn-based negative electrode active materials. Si-based negative electrode active materials can include silicon, silicon-carbon composites, SiO x (where 0 < x ≤ 2), Si-Q alloys (where Q is an alkali metal, alkaline earth metal, Group 13 element, Group 14 element (excluding Si), Group 15 element, Group 16 element, transition metal, rare earth element, and / or their combination (e.g., any suitable combination thereof)) and / or their combination (e.g., any suitable combination thereof). Sn-based negative electrode active materials can include Sn, SnO x (where 0 < x ≤ 2, e.g., SnO2), Sn-based alloys, and / or their combination (e.g., any suitable combination thereof).

[0079] The silicon-carbon composite can be a composite of silicon and amorphous carbon. According to one or more embodiments, the silicon-carbon composite can have a structure in which amorphous carbon is coated on the surface of silicon particles. For example, the silicon-carbon composite may include secondary particles (cores) in which primary silicon particles are concentrated and an amorphous carbon coating (shell) located on the surface of the secondary particles. Amorphous carbon may also be located between the primary silicon particles, and, for example, the primary silicon particles may be coated with amorphous carbon. The secondary particles may be dispersed in an amorphous carbon matrix.

[0080] The silicon-carbon composite may further include crystalline carbon. For example, the silicon-carbon composite may include a core comprising crystalline carbon and silicon particles, and may also include an amorphous carbon coating on the surface of the core.

[0081] Si-based and / or Sn-based negative electrode active materials can be used in combination with carbon-based negative electrode active materials.

[0082] Diaphragm 30

[0083] Depending on the type of rechargeable lithium battery, the separator 30 may be present between the positive electrode 10 and the negative electrode 20. The separator 30 may include one or more selected from polyethylene separators, polypropylene separators, and polyvinylidene fluoride separators, and may have multiple layers, such as polyethylene / polypropylene double-layer separators, polyethylene / polypropylene / polyethylene triple-layer separators, and / or polypropylene / polyethylene / polypropylene triple-layer separators.

[0084] The diaphragm 30 may include a porous substrate and a coating on one or both (e.g., opposite) surfaces of the porous substrate. The coating may include organic materials, inorganic materials and / or combinations thereof (e.g., any suitable combination thereof).

[0085] The porous substrate may be a polymer layer comprising a selection from: polyolefins (such as polyethylene and / or polypropylene), polyesters (such as polyethylene terephthalate and / or polybutylene terephthalate), polyacetals, polyamides, polyimides, polycarbonates, polyetherketones, polyaryletherketones, polyetherimides, polyamideimides, polybenzimidazoles, polyethersulfones, polyphenylene ethers, cyclic olefin copolymers, polyphenylene sulfide, polyethylene naphthalate, glass fibers, and polytetrafluoroethylene (e.g., Teflon). TM The polymer layer may include copolymers and / or mixtures comprising two or more of the materials mentioned above.

[0086] Organic materials may include polyvinylidene fluoride copolymers and / or (meth)acrylic acid copolymers.

[0087] Inorganic materials 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 / or combinations thereof (e.g., any suitable combination thereof), but this disclosure is not limited thereto.

[0088] Organic and inorganic materials can be mixed in a coating, or they can exist in the form of a layer of coatings including organic materials and coatings including inorganic materials.

[0089] Electrolyte ELL

[0090] Electrolytes (ELLs) used in rechargeable lithium batteries may include non-aqueous organic solvents and lithium salts.

[0091] Non-aqueous organic solvents can be used as media for transporting ions that participate in the electrochemical reactions of a battery.

[0092] Non-aqueous organic solvents may include carbonate solvents, ester solvents, ether solvents, ketone solvents, alcohol solvents, aprotic solvents and / or combinations thereof (e.g., any suitable combination thereof).

[0093] Carbonate solvents may include dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), ethyl methyl carbonate (EMC), ethylene carbonate (EC), propylene carbonate (PC), and / or butyl carbonate (BC).

[0094] Ester solvents may include methyl acetate, ethyl acetate, n-propyl acetate, dimethyl acetate, methyl propionate, ethyl propionate, decanoic acid lactone, mevalonate lactone, caprolactone, and / or propyl propionate (PP).

[0095] Ether solvents may include dibutyl ether, tetraethylene glycol dimethyl ether, diethylene glycol dimethyl ether, ethylene glycol dimethyl ether, 2-methyltetrahydrofuran, 2,5-dimethyltetrahydrofuran, and / or tetrahydrofuran. Ketone solvents may include cyclohexanone. Alcohol solvents may include ethanol and / or isopropanol, and aprotic solvents may include nitrile solvents (such as R-CN, where R is a hydrocarbon group having a C2-C20 straight-chain, branched, or cyclic structure, and may include double bonds, aromatic rings, and / or ether bonds); amides (such as dimethylformamide); dioxolane (such as 1,3-dioxolane and / or 1,4-dioxolane); and / or sulfolane.

[0096] Non-aqueous organic solvents can be used alone or in mixtures of two or more substances.

[0097] Additionally, if (for example, when) a carbonate solvent is used, cyclic carbonates and chain carbonates can be mixed and used, and cyclic carbonates and chain carbonates can be mixed in a volume ratio of about 1:1 to about 1:9.

[0098] Lithium salts can be materials dissolved in non-aqueous organic solvents to serve as a source of lithium ions in batteries and can play a role in ensuring or facilitating the basic operation of rechargeable lithium batteries and in promoting the movement of lithium ions between the positive and negative electrodes. Lithium salts may include, for example, those selected from LiPF6, LiBF4, LiSbF6, LiAsF6, LiClO4, LiAlO2, LiAlCl4, LiPO2F2, LiCl, LiI, LiN(SO3C2F5)2, Li(FSO2)2N (lithium bis(fluorosulfonyl)imide, LiFSI), LiC4F9SO3, LiN(C x F 2x+1 SO2)(C y F 2y+1 At least one of the following: SO2 (where x and y are integers from 1 to 20), lithium trifluoromethanesulfonate, lithium tetrafluoroethanesulfonate, lithium difluoro(oxalate)borate (LiDFOB), lithium difluorobis(oxalate)phosphate (LiDFBOP), and lithium bis(oxalate)borate (LiBOB).

[0099] The electrolyte for a rechargeable lithium battery according to one or more embodiments of the present disclosure will be described in more detail below.

[0100] An electrolyte for a rechargeable lithium battery according to one or more embodiments may include a non-aqueous organic solvent, a lithium salt, and additives, wherein the additives may include cyclic carbonate compounds comprising azide groups.

[0101] Additives will be discussed in more detail below.

[0102] Electrolytes can be prepared by a mixing process in which lithium salts are dissolved in a non-aqueous organic solvent and additives are added to the mixture. Any suitable electrolyte mixing process in the field of electrolyte manufacturing can be utilized, and those skilled in the art should be able to select and apply appropriate processes.

[0103] In one or more embodiments, the non-aqueous organic solvent may include a cyclic carbonate solvent. Cyclic carbonate solvents may include ethylene carbonate (EC), propylene carbonate (PC), butyl carbonate (BC), vinylene carbonate (VC), and / or vinyl ethylene carbonate (VEC), but this disclosure is not limited thereto. The cyclic carbonate solvent may be present in an amount of about 5 to about 50 parts by volume relative to 100 parts by volume of the non-aqueous organic solvent. In one or more embodiments, the cyclic carbonate solvent may be present in an amount of about 10 to about 30 parts by volume relative to 100 parts by volume of the non-aqueous organic solvent.

[0104] In one or more embodiments, the non-aqueous organic solvent may include linear carbonate solvents and cyclic carbonate solvents. Linear carbonate solvents may include, for example, dimethyl carbonate (DMC), diethyl carbonate (DEC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), and / or ethyl methyl carbonate (EMC), but this disclosure is not limited thereto. The volume ratio of the linear carbonate solvent to the cyclic carbonate solvent may be in the range of about 50:50 to about 95:5. In one or more embodiments, the volume ratio of the linear carbonate solvent to the cyclic carbonate solvent may be in the range of about 70:30 to about 90:10.

[0105] In one or more embodiments, the non-aqueous organic solvent may include chain ester solvents, chain carbonate solvents, and cyclic carbonate solvents. Chain ester solvents may include methyl acetate, ethyl acetate, n-propyl acetate, dimethyl acetate, methyl propionate, ethyl propionate, and / or propyl propionate (PP), but this disclosure is not limited thereto. The value of “A” may be defined as the sum of the volumes of the chain ester solvent and the chain carbonate solvent. The value of “B” may be defined as the volume of the cyclic carbonate solvent. The ratio of A to B (or A:B) may be in the range of about 50:50 to about 95:5. In one or more embodiments, the ratio of A to B (or A:B) may be in the range of about 70:30 to about 90:10.

[0106] When the type (variety) and volume ratio of the non-aqueous organic solvent are satisfied, the additive may suitably or appropriately maintain its solubility. However, the embodiments described herein are merely examples of this disclosure, and this disclosure is not limited thereto.

[0107] In one or more embodiments, the lithium salt may include those selected from LiPF6, LiBF4, LiSbF6, LiAsF6, LiClO4, LiAlO2, LiAlCl4, LiPO2F2, LiCl, LiI, LiN(SO3C2F5)2, Li(FSO2)2N (lithium bis(fluorosulfonyl)imide, LiFSI), LiC4F9SO3, LiN(Cx F 2x+1 SO2)(C y F 2y+1 SO2 (where x and y are integers from 1 to 20), lithium trifluoromethanesulfonate, lithium tetrafluoroethanesulfonate, lithium difluoro(oxalate)borate (LiDFOB), lithium difluorobis(oxalate)phosphate (LiDFBOP), and lithium bis(oxalate)borate (LiBOB).

[0108] The lithium salt can have a concentration of about 0.1 M to about 2.0 M. For example, the lithium salt can have a concentration equal to or greater than about 0.5 M or equal to or greater than about 1.0 M. The lithium salt can have a concentration equal to or less than about 2.0 M, equal to or less than about 1.7 M, or equal to or less than about 1.5 M. If (for example, when) the lithium salt has a concentration of about 0.1 M to about 2.0 M, the electrolyte can suitably or appropriately maintain its conductivity and viscosity.

[0109] additive

[0110] The additives according to this disclosure may include cyclic carbonate compounds, which include azide-containing groups.

[0111] Cyclic carbonate compounds can be represented by chemical formula 1 or chemical formula 2.

[0112] Chemical Formula 1

[0113]

[0114] In chemical formula 1,

[0115] The subscript n can be an integer from 2 to 5.

[0116] R1 can be hydrogen, substituted or unsubstituted C1-C10 alkyl, substituted or unsubstituted C2-C10 alkenyl, substituted or unsubstituted C2-C10 alkynyl, or azide-containing group, each independently.

[0117] The R1 groups can be independently the same as or different from each other.

[0118] At least one of the R1 groups may be an azide-containing group.

[0119] Chemical formula 2

[0120]

[0121] In chemical formula 2,

[0122] The subscript m can be an integer from 0 to 3.

[0123] The subscript z can be an integer from 0 to 3.

[0124] The sum of m and z can be an integer equal to or less than 3.

[0125] R2 can be hydrogen, substituted or unsubstituted C1-C10 alkyl, substituted or unsubstituted C2-C10 alkenyl, substituted or unsubstituted C2-C10 alkynyl, or azide-containing group, each independently.

[0126] The R2 groups can be independently the same as or different from each other.

[0127] At least one of the R2 groups may be an azide-containing group.

[0128] The azide group can be an azide group or a substituted or unsubstituted C1-C4 alkyl azide group.

[0129] The alkyl azide group may be represented by -R-N3. The alkyl azide group may include methyl azide, ethyl azide, n-propyl azide and / or isopropyl azide, but this disclosure is not limited thereto.

[0130] In one or more embodiments, if (for example, when) n is 2 in Formula 1, the compound may be an ethylene carbonate (EC) comprising four R1s. The four R1s may be the same or different. At least one of the four R1s may be an azide-containing group.

[0131] In one or more embodiments, the compound may be a vinylene carbonate (VC) comprising two R2 groups if (for example, when) m and z are each 0 in formula 2. The two R2 groups may be the same or different. At least one of the two R2 groups may be an azide-containing group.

[0132] In one or more embodiments, n can be 2 or 3, and the sum of m and z can be an integer equal to or less than 1. For example, the ring portion of the compound of formula 2 can be pentagonal or hexagonal.

[0133] In one or more embodiments, n can be 2, and m and z can each be 0. For example, the ring portion of the compound can be pentagonal.

[0134] In one or more embodiments, R1 may each independently be hydrogen, a substituted or unsubstituted C1-C5 alkyl, a substituted or unsubstituted C2-C5 alkenyl, a substituted or unsubstituted C2-C5 alkynyl, or an azide-containing group. R2 may each independently be hydrogen, a substituted or unsubstituted C1-C5 alkyl, a substituted or unsubstituted C2-C5 alkenyl, a substituted or unsubstituted C2-C5 alkynyl, or an azide-containing group.

[0135] For example, R1 can be hydrogen or an azide group independently, and R2 can be hydrogen or an azide group independently.

[0136] In one or more embodiments, the compound may be represented by chemical formula 1-1 or chemical formula 2-1.

[0137] Chemical Formula 1-1

[0138]

[0139] Chemical formula 2-1

[0140]

[0141] In one or more embodiments, the compound may be represented by chemical formulas 1-2.

[0142] Chemical formula 1-2

[0143]

[0144] The additive may be present in an amount of about 0.01 parts by weight to about 5 parts by weight relative to 100 parts by weight of electrolyte. For example, the additive may be present in an amount of about 0.01 parts by weight to about 3 parts by weight relative to 100 parts by weight of electrolyte. As another example, the additive may be present in an amount of about 0.01 parts by weight to about 1 part by weight relative to 100 parts by weight of electrolyte. The amount of additive may refer to the weight of the additive included in the electrolyte relative to the total weight of the electrolyte. If the amount of additive falls within any of the above ranges, the effect of improving battery performance at high voltage and high temperature can be maximized or increased.

[0145] In cyclic carbonate compounds, the azide-containing group can dissociate from the cyclic structure (ring portion) comprising the carbonate to form a LiN-based inorganic component film on the positive electrode. The LiN-based inorganic component film may include, for example, Li3N and / or LiN. x O y The membrane prevents or reduces further oxidation of the positive electrode, thereby improving battery performance.

[0146] After the dissociation of the azide-containing groups, the residual cyclic carbonate compounds can be used as non-aqueous organic solvents in the electrolyte. These residual cyclic carbonate compounds can be, for example, ethylene carbonate (EC) and / or vinylene carbonate (VC). Repeated charging and discharging of the battery can damage the solid electrolyte interface (SEI) of the negative electrode. Non-aqueous organic solvents in the electrolyte can be used to regenerate the damaged SEI. Repeated damage and regeneration of the SEI can lead to electrolyte consumption, which may result in reduced battery life and performance. The residual cyclic carbonate compounds can have the effect of continuously replenishing the consumed non-aqueous organic solvents.

[0147] Due to the structural properties of this compound, the additive according to this disclosure can provide protection for both the positive and negative electrodes during the reaction process. Accordingly, the battery can undergo essentially continuous self-repair. In other words, the additive can help form a protective film on the positive electrode and help replenish the non-aqueous organic solvent, thereby promoting the regeneration of damaged SEI during lithium battery charging and discharging.

[0148] At high temperatures, the degradation of both the positive and negative electrodes may be accelerated. Therefore, the self-healing effect of the additives according to this disclosure becomes more pronounced at high temperatures. High temperatures can be equal to or greater than approximately 40°C, 50°C, or 60°C.

[0149] Rechargeable lithium batteries

[0150] Based on their shape, rechargeable lithium batteries can be classified into cylindrical batteries, prismatic batteries, pouch-type batteries, and / or coin-type batteries. Figures 2-5 Each illustration shows a simplified diagram of a rechargeable lithium battery according to one or more embodiments, wherein... Figure 2 A cylindrical battery is shown. Figure 3 A prismatic battery is shown, and Figure 4 and Figure 5 This shows pouch-type (type) batteries. (Reference) Figures 2-5 The rechargeable lithium battery 100 may include an electrode assembly 40 (with a separator 30 inserted between a positive electrode 10 and a negative electrode 20), and may also include a housing 50 (containing the electrode assembly 40). The positive electrode 10, negative electrode 20, and separator 30 may be impregnated with an electrolyte. Figure 2 The text explains that the rechargeable lithium battery 100 may include a sealing member 60 of a sealed housing 50. Additionally, as... Figure 3 The text explains that the rechargeable lithium battery 100 may include a positive electrode lead connector 11, a positive electrode terminal 12, a negative electrode lead connector 21, and a negative electrode terminal 22. For example... Figure 4 and Figure 5 As shown, the rechargeable lithium battery 100 may include electrode terminals 70 or positive electrode terminals 71 and negative electrode terminals 72, which can be used as electrical paths for guiding current generated in the electrode assembly 40 to the outside.

[0151] The rechargeable lithium battery according to one or more embodiments of this disclosure can be used in motor vehicles, mobile phones and / or any other electronic devices, but this disclosure is not limited thereto. For example, the rechargeable lithium battery can be used as an energy storage power source and / or power wall for home energy storage units (e.g., it can be used as an energy storage source for an energy storage system (ESS)), and as a drive power source (automobile battery) for hybrid vehicles or electric vehicles.

[0152] The rechargeable lithium battery according to the present disclosure may include: a positive electrode including a positive electrode active material; a negative electrode including a negative electrode active material; and an electrolyte for a rechargeable lithium battery according to the present embodiment.

[0153] The positive electrode active material may include a lithium composite oxide represented by Chemical Formula 3.

[0154] Chemical Formula 3

[0155] Li x M 1 y M 2 z M 3 1-y-z O 2-a X a .

[0156] The subscripts x, a, y, and z may satisfy the following relationships: 0.5 ≤ x ≤ 1.8, 0 ≤ a ≤ 0.05, 0 < y ≤ 1, 0 ≤ z ≤ 1, and 0 < y + z ≤ 1.

[0157] M 1 、M 2 和M 3 may each independently include at least one element selected from Ni, Co, Mn, Al, B, Ba, Ca, Ce, Cr, Fe, Mo, Nb, Si, Sr, Mg, Ti, V, W, Zr, Y, and La.

[0158] X may include at least one element selected from F, S, P, and Cl.

[0159] In one or more embodiments, in Chemical Formula 3, M 1 may be Ni. For example, in Chemical Formula 3, M 1 may be Ni, M 2 may be Co, and M 3 may be Al. For example, the positive electrode active material may include an NCA (nickel cobalt aluminum) type positive electrode active material.

[0160] Due to the inherent instability of the Ni element, the positive electrode active material containing Ni may undergo a significant (e.g., relatively strong) side reaction with the electrolyte. Therefore, the battery stabilizing effect of the additive according to the present disclosure can be more obvious in the positive electrode active material. However, there is no limitation on the type (species) of the positive electrode active material included in the battery according to the present disclosure.

[0161] The negative electrode active material may be a carbon-based negative electrode active material, a Si-based negative electrode active material, a Sn-based negative electrode active material, and / or a combination thereof (e.g., any suitable combination thereof).

[0162] In one or more embodiments, the active material of the Si-type negative electrode may include a silicon-carbon composite.

[0163] Some embodiments and comparative examples of this disclosure will be described below. However, the embodiments described below are merely examples, and this disclosure is not limited to one or more embodiments discussed herein.

[0164] Synthesis example 1

[0165] Add 75 mmol of ethylene chloride carbonate and 120 mL of acetone to a round-bottom flask and stir. Add 375 mmol of sodium azide to 120 mL of distilled water and dissolve completely.

[0166] The dissolved distilled water mixture was slowly added dropwise to the mixture of ethylene chloride carbonate and acetone. The reaction was terminated by stirring at room temperature for 3 hours.

[0167] The mixture was extracted three times with ethyl acetate and distilled water. The ethyl acetate layer was treated with MgSO4 and then concentrated. The concentrated reaction mixture was dried under vacuum to obtain the compound represented by chemical formula 1-1. Figure 6 The explanation illustrates the compound according to Synthesis Example 1. 1 A graph of H-NMR spectral results.

[0168] Chemical Formula 1-1

[0169]

[0170] Synthesis example 2

[0171] Add 81 mmol of 4-chloro-1,3-dioxane-2-one and 150 mL of acetone to a round-bottom flask and stir. Add 405 mmol of sodium azide to 150 mL of distilled water and dissolve completely.

[0172] The dissolved distilled water mixture was slowly added dropwise to a mixed solution of 4-chloro-1,3-dioxacyclopenten-2-one and acetone. The reaction was terminated by stirring at room temperature for 3 hours.

[0173] The mixture was extracted three times with ethyl acetate and distilled water. The ethyl acetate layer was treated with MgSO4 and then concentrated. The concentrated reaction mixture was then dried under vacuum to obtain the compound represented by chemical formula 2-1.

[0174] Chemical formula 2-1

[0175]

[0176] Chemical formula 2-1 was synthesized as a representative example of chemical formula 2, but it was not used in the implementation.

[0177] Implementation Method 1

[0178] (1) Preparation of electrolyte

[0179] 1.15 M LiPF6 was dissolved in a non-aqueous organic solvent containing ethylene carbonate (EC), ethyl methyl carbonate (EMC), and dimethyl carbonate (DMC) mixed in a volume ratio of approximately 20:40:40. An electrolyte was prepared by adding an additive, including the compound represented by chemical formula 1-1 obtained in Synthesis Example 1. The additive was present in an amount of 0.1 parts by weight relative to 100 parts by weight of the electrolyte.

[0180] (2) Manufacturing of rechargeable lithium batteries

[0181] LiNi will be used as the active material for the positive electrode. 0.91 Co 0.07 Al 0.02 O2, polyvinylidene fluoride as a binder, and Ketjen black as a conductive material are mixed in a weight ratio of 97:2:1, and the mixture is dispersed in N-methylpyrrolidone to prepare a slurry for positive electrode active material.

[0182] The positive electrode active material slurry was coated onto an aluminum current collector with a thickness of 14 μm, dried at 110 °C, and then pressed to manufacture the positive electrode.

[0183] Artificial graphite and silicon nanoparticles, used as negative electrode active materials, were mixed in a weight ratio of 93:7; styrene-butadiene rubber (SBR), used as a binder; and carboxymethyl cellulose (CMC), used as a tackifier, were mixed in a weight ratio of 97:1:2. The mixture was then dispersed in distilled water to prepare a negative electrode active material slurry.

[0184] The negative electrode active material slurry was coated onto a copper current collector with a thickness of 10 μm, dried at 100 °C, and then pressed to manufacture the negative electrode.

[0185] A positive electrode, a negative electrode, and a polyethylene separator with a thickness of 25 μm are assembled to manufacture an electrode assembly, and an electrolyte is introduced (impregnated) to manufacture a rechargeable lithium battery.

[0186] Implementation Method 2

[0187] The electrolyte and rechargeable lithium battery are manufactured in essentially the same manner as in Embodiment 1, except that the amount of additive is 0.5 parts by weight.

[0188] Implementation Method 3

[0189] The electrolyte and rechargeable lithium battery are manufactured in a manner substantially the same as in Embodiment 1, except that the amount of additive is 1 part by weight.

[0190] Implementation Method 4

[0191] The electrolyte and rechargeable lithium battery are manufactured in essentially the same manner as in Embodiment 1, except that the amount of additive is 3 parts by weight.

[0192] Implementation Method 5

[0193] The electrolyte and rechargeable lithium battery are manufactured in essentially the same manner as in Embodiment 1, except that the amount of additive is 5 parts by weight.

[0194] Implementation Method 6

[0195] The electrolyte and rechargeable lithium battery were manufactured in a manner substantially the same as in Embodiment 1, except that the compound represented by chemical formula 1-1 obtained in Synthesis Example 1 was replaced with the compound represented by chemical formula 1-2, and the amount of additive was 1 part by weight.

[0196] Chemical formula 1-2

[0197]

[0198] Comparative Example 1

[0199] The electrolyte and rechargeable lithium battery were manufactured in a manner substantially the same as in Embodiment 1, except that the electrolyte did not include the compound represented by chemical formula 1-1 obtained in Synthesis Example 1.

[0200] Assessment 1: Float Charge

[0201] The positive electrode and electrolyte of Embodiment 1 are used to manufacture a Type 2032 coin half-cell. A lithium metal counter electrode is used as the negative electrode, and a polyethylene diaphragm is inserted between the positive electrode and the lithium metal counter electrode.

[0202] The manufactured coin-shaped half-cell was kept at 45°C and 4.4V for 250 hours, and then the battery current was measured. The leakage current was calculated according to Equation 1. The same evaluation method was applied to Embodiments 2 to 6 and Comparative Example 1. The results are shown in Table 1.

[0203] Equation 1

[0204] Leakage current = Current after 250 hours of storage / Mass of active material

[0205] Assessment 2: Open-circuit voltage (OCV) during high-temperature storage

[0206] Prismatic battery cells with a rated current of 5.8 amperes were manufactured using the electrolytes of Embodiments 1 to 6 and Comparative Example 1, the negative electrode of a silicon-carbon composite, and the positive electrode of NCA, respectively. The rechargeable lithium batteries were charged at 25°C, 0.33C, 4.25V, and 0.05C cutoff conditions, and the OCV values ​​of the batteries were measured (“Initial OCV (V)” in Table 1). The rechargeable lithium batteries were placed at 60°C for 10 days, and then the OCV values ​​of the batteries were measured (“OCV (V) after 10 days at 60°C” in Table 1). The results are shown in Table 1.

[0207] Assessment 3: High-Temperature Storage

[0208] Prismatic battery cells with a rated current of 5.8 amps were manufactured using the electrolytes of Embodiments 1 to 6 and Comparative Example 1, the negative electrode of a silicon-carbon composite, and the positive electrode of NCA, respectively. The rechargeable lithium-ion batteries were charged at 25°C, 0.33C, 4.25V, and a 0.05C cutoff condition, and then discharged at 25°C, 0.33C, and a 2.8V cutoff condition, and the initial characteristic values ​​of the batteries were measured. The rechargeable lithium-ion batteries were placed at 60°C for 60 days, and then charged and discharged once under the same conditions as above, and the characteristic values ​​of the batteries were measured. The capacity retention rate and the rate of increase in resistance were calculated according to Equations 2 and 3, respectively. A 1C current was applied for 10 seconds, and the DC internal resistance (DCIR) was measured using dR = dV / dI. The results are shown in Table 1.

[0209] Equation 2

[0210] Capacity retention rate (%) = (Discharge capacity after 60 days / Initial discharge capacity) × 100

[0211] Equation 3

[0212] Resistance increase rate (%) = (DCIR after 60 days / Initial DCIR) × 100

[0213] Assessment 4: High-Temperature Lifespan

[0214] Prismatic battery cells with a rated current of 5.8 amps were manufactured using the electrolytes of Embodiments 1 to 6 and Comparative Example 1, the negative electrode of the silicon-carbon composite, and the positive electrode of NCA, respectively. The rechargeable lithium-ion battery was charged at 25°C, 0.33C, 4.25V, and a 0.05C cutoff condition, and the initial characteristic values ​​of the battery were measured. 100 charge / discharge cycles were performed at a high temperature (45°C), and then the characteristic values ​​of the battery were measured at 25°C. If (for example, when) cycling was performed, the charging conditions were 45°C, 0.33C, 4.25V, and a 0.05C cutoff. The discharging conditions were 45°C, 0.33C, and a 2.8V cutoff voltage. The capacity retention rate and the rate of increase in resistance were calculated according to Equations 4 and 5, respectively. A 1C current was applied for 10 seconds, and the DC internal resistance (DCIR) was measured using dR = dV / dI. The results are shown in Table 1.

[0215] Equation 4

[0216] Capacity retention (%) = (Discharge capacity after 100 cycles / Initial discharge capacity) × 100

[0217] Equation 5

[0218] Resistance increase rate (%) = (DCIR after 100 cycles / Initial DCIR) × 100

[0219] Table 1

[0220]

[0221]

[0222] Referring to Table 1, it can be seen that, compared to Comparative Example 1, Embodiments 1 to 6 of this disclosure exhibit superior or suitable characteristics in terms of float charging, OCV, high-temperature storage, and high-temperature lifespan. For example, it can be determined that the additives according to this disclosure have the effect of significantly or appropriately improving battery performance at high voltages and high temperatures.

[0223] The additives disclosed herein may have the effect of significantly or appropriately improving battery performance at high voltage and high temperature.

[0224] Rechargeable lithium batteries with additives can have superior or improved performance at high voltages and high temperatures.

[0225] Although this disclosure has been described in conjunction with what is now considered to be exemplary embodiments, it should be understood that this disclosure is not limited to the disclosed embodiments and is intended to cover one or more suitable modifications and equivalent arrangements included within the spirit and scope of the claims and their equivalents. Therefore, the foregoing embodiments should be understood as exemplary and not as limiting this disclosure in any way.

Claims

1. An electrolyte for a rechargeable lithium battery, comprising: Non-aqueous organic solvents; Lithium salts; and additive, The additives mentioned above include cyclic carbonate compounds, which include azido groups.

2. The electrolyte of claim 1, wherein the azide-containing group is an azide group or a substituted or unsubstituted C1-C4 alkyl azide group. The term "substitution" refers to the substitution of at least one hydrogen atom of a substituent or compound by the following: deuterium, halogen, hydroxyl, amino, C1-C30 amino, nitro, C1-C40 silyl, C1-C30 alkyl, C1-C10 alkylsilyl, C6-C30 arylsilyl, C3-C30 cycloalkyl, C3-C30 heterocycloalkyl, C6-C30 aryl, C2-C30 heteroaryl, C1-C20 alkoxy, C1-C10 fluoroalkyl, cyano, and / or combinations thereof.

3. The electrolyte of claim 1, wherein the cyclic carbonate compound is represented by chemical formula 1 or chemical formula 2: Chemical Formula 1 In chemical formula 1, n is an integer from 2 to 5. R1 is independently hydrogen, a substituted or unsubstituted C1-C10 alkyl, a substituted or unsubstituted C2-C10 alkenyl, a substituted or unsubstituted C2-C10 alkynyl, or the azide-containing group. R1 are each independently the same or different from each other, and At least one of R1 is the azide-containing group. Chemical formula 2 In chemical formula 2, m is an integer from 0 to 3. z is an integer between 0 and 3. The sum of m and z is an integer equal to or less than 3. R2 is independently hydrogen, a substituted or unsubstituted C1-C10 alkyl, a substituted or unsubstituted C2-C10 alkenyl, a substituted or unsubstituted C2-C10 alkynyl, or the azide-containing group. R2 values ​​are independently the same or different from each other, and At least one of R2 is the azide-containing group.

4. The electrolyte as described in claim 3, wherein... n is 2 or 3, and The sum of m and z is an integer equal to or less than 1.

5. The electrolyte as described in claim 3, wherein... n is 2, and m and z are 0.

6. The electrolyte as described in claim 3, wherein... R1 is independently hydrogen, a substituted or unsubstituted C1-C5 alkyl group, a substituted or unsubstituted C2-C5 alkenyl group, a substituted or unsubstituted C2-C5 alkynyl group, or the azide-containing group, and R2 is independently hydrogen, a substituted or unsubstituted C1-C5 alkyl group, a substituted or unsubstituted C2-C5 alkenyl group, a substituted or unsubstituted C2-C5 alkynyl group, or the azide-containing group.

7. The electrolyte as described in claim 3, wherein... R1 is each independently hydrogen or the azide-containing group, and R2 is either hydrogen or the azide-containing group.

8. The electrolyte of claim 3, wherein the cyclic carbonate compound is represented by chemical formula 1-1 or chemical formula 2-1. Chemical Formula 1-1 Chemical formula 2-1 9. The electrolyte of claim 1, wherein the additive is present in an amount of 0.01 to 5 parts by weight relative to 100 parts by weight of the electrolyte.

10. The electrolyte according to claim 1, wherein the non-aqueous organic solvent includes a cyclic carbonate solvent, and wherein, relative to 100 parts by volume of the non-aqueous organic solvent, the cyclic carbonate solvent is present in an amount of 5 to 50 parts by volume.

11. The electrolyte of claim 1, wherein the lithium salt comprises a group selected from LiPF6, LiBF4, LiSbF6, LiAsF6, LiClO4, LiAlO2, LiAlCl4, LiPO2F2, LiCl, LiI, LiN(SO3C2F5)2, Li(FSO2)2N, LiC4F9SO3, LiN(C x F 2x+1 SO2)(C y F 2y+1 (SO2), lithium trifluoromethanesulfonate, lithium tetrafluoroethanesulfonate, lithium difluoro(oxalate)borate, lithium difluorobis(oxalate)phosphate and lithium bis(oxalate)borate, wherein x and y are integers from 1 to 20.

12. The electrolyte according to claim 1, wherein the concentration of the lithium salt is in the range of 0.1M to 2.0M.

13. A cyclic carbonate compound represented by Chemical Formula 1 or Chemical Formula 2: Chemical Formula 1 In Chemical Formula 1, n is an integer from 2 to 5, R1 is independently hydrogen, a substituted or unsubstituted C1-C10 alkyl group, a substituted or unsubstituted C2-C10 alkenyl group, a substituted or unsubstituted C2-C10 alkynyl group or an azide group-containing group, R1 are independently the same or different from each other, and at least one of R1 is the azide group-containing group, Chemical Formula 2 In Chemical Formula 2, m is an integer from 0 to 3, z is an integer from 0 to 3, the sum of m and z is an integer equal to or less than 3, R2 is independently hydrogen, a substituted or unsubstituted C1-C10 alkyl group, a substituted or unsubstituted C2-C10 alkenyl group, a substituted or unsubstituted C2-C10 alkynyl group or the azide group-containing group, R2 are independently the same or different from each other, and at least one of R2 is the azide group-containing group.

14. The cyclic carbonate compound according to claim 13, wherein the azide group-containing group is an azide group or a substituted or unsubstituted C1-C4 alkyl azide group.

15. The cyclic carbonate compound according to claim 13, wherein the cyclic carbonate compound is represented by Chemical Formula 1-1 or Chemical Formula 2-1, Chemical Formula 1-1 Chemical Formula 2-1 16. A rechargeable lithium battery, comprising: a positive electrode including a positive electrode active material; a negative electrode including a negative electrode active material; and the electrolyte for a rechargeable lithium battery according to any one of claims 1 to 12.

17. The rechargeable lithium battery according to claim 16, wherein the positive electrode active material includes a lithium composite oxide represented by Chemical Formula 3: Chemical Formula 3 Li x M 1 y M 2 z M 3 1-y-z O 2-a X a , In Chemical Formula 3, 0.5 ≤ x ≤ 1.8, 0 ≤ a ≤ 0.05, 0 < y ≤ 1, 0 ≤ z ≤ 1, and 0 < y + z ≤ 1, M 1 M 2 and M 3 Each independently includes at least one selected from Ni, Co, Mn, Al, B, Ba, Ca, Ce, Cr, Fe, Mo, Nb, Si, Sr, Mg, Ti, V, W, Zr, Y, and La, and X includes at least one element selected from F, S, P, and Cl.

18. The rechargeable lithium battery of claim 17, wherein, In chemical formula 3, M 1 For Ni.

19. The rechargeable lithium battery according to claim 16, wherein the negative electrode active material includes a carbon-based negative electrode active material, a Si-based negative electrode active material, a Sn-based negative electrode active material or a combination thereof.

20. The rechargeable lithium battery according to claim 19, wherein the Si-based negative electrode active material is a silicon-carbon composite.

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