Control of lithium- and manganese-rich positive active material compositions through controlled formation processes of rechargeable lithium batteries

Abstract

An active material for positive electrodes in lithium-ion batteries is given the formula Li 1,01+a Mn 0,50+b Ni 0,25+c Co x O2 is represented, where 0 < a < 0.14, 0 ≤ b ≤ 0.10, 0 ≤ c ≤ 0.24 and 0 ≤ x ≤ 0.10. The active material can include surface coatings such as oxides, fluorides or phosphates and its composition can be partially substituted with dopant cations (magnesium, titanium, boron, aluminum) or dopant anions (fluorine, chlorine).

Description

AREA OF TECHNOLOGY

[0001] Active materials for positive electrodes for lithium-ion batteries are provided in at least one aspect. GENERAL STATE OF THE ART

[0002] A lithium- and manganese-rich (LMR) active material for positive electrodes has been considered a promising next-generation cathode material due to its high gravimetric energy density compared to currently used nickel-cobalt-manganese (NCM) and nickel-cobalt-aluminium (NCA) materials. SUMMARY

[0003] An active material for positive electrodes in lithium-ion batteries is provided. This active material comprises a compound known by the general formula Li 1,01+a Mn 0,50+b Ni 0,25+c Co xO2 is represented where 0 < a < 0.14, 0 ≤ b ≤ 0.10, 0 ≤ c ≤ 0.24, and 0 ≤ x ≤ 0.10. The active material for positive electrodes can typically include known surface coatings, such as aluminum oxide, zirconium oxide, or lithium phosphate. Additionally, Mn, Ni, Co, and O in the compound can be partially substituted with various dopant cations, such as magnesium, titanium, boron, or aluminum, or with various dopant anions, such as fluorine or chlorine. The particle size distribution of the active material can have a D50 value in the range of 1 µm to 20 µm. Furthermore, the active material can have an unextracted residual lithium content between 0.27 and 0.35 after the first formation charge and a lithium content between 1.00 and 1.05 after the first formation discharge.After a second formation charge, the lithium content can be in the range between 0.30 and 0.38, and after the second formation discharge, it can be in the range between 1.00 and 1.05.

[0004] A positive electrode for a lithium-ion battery is provided. This electrode includes an active material for positive electrodes, comprising a compound known by the formula Li 1,01+a Mn 0,50+b Ni 0,25+c Co xO2 is represented where 0 < a < 0.14, 0 ≤ b ≤ 0.10, 0 ≤ c ≤ 0.24, and 0 ≤ x ≤ 0.10. Mn, Ni, Co, and O in the compound may be partially substituted with various dopant cations, such as magnesium, titanium, boron, or aluminum, or with various dopant anions, such as fluorine or chlorine. The particle size distribution of the active material may have a D50 value in the range of 1 µm to 20 µm. Furthermore, the unrecovered lithium content in the positive electrode after an initial formation charge may be in the range of 0.27 to 0.35, while the lithium content in the active material after an initial formation discharge may be in the range of 1.00 to 1.05. After a second formation charge, the lithium content can range between 0.30 and 0.38, and after a second formation discharge, it can range between 1.00 and 1.05. A rechargeable lithium-ion battery is provided.The battery may contain at least one lithium-ion battery cell, each cell comprising a positive electrode which includes a positive electrode active material designated by the formula Li. 1,01+a Mn 0,50+b Ni 0,25+c Co x O2 is represented, where 0 < a < 0.14, 0 ≤ b ≤ 0.10, 0 ≤ c ≤ 0.24 and 0 ≤ x ≤ 0.10. The battery may further include a negative electrode, which may contain a negative active material such as graphite, silicon, or a silicon-carbon composite. The battery may also include an electrolyte containing a lithium salt and an organic solvent, wherein the lithium salt is selected from lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(trifluoromethanesulfonyl)imide, lithium bis(fluorosulfonyl)imide, or combinations thereof. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1A is a schematic cross-sectional view of a positive electrode incorporating a cathode active material on a single side of a current collector; Fig. Figure 1B is a schematic cross-sectional view of a positive electrode incorporating a cathode active material on both sides of a current collector; Fig. Figure 2 is a schematic cross-sectional view of a battery cell, showing the positive electrode made of Fig. 1A includes; and Fig. Figure 3 is a schematic cross-sectional view of a battery pack, which contains the battery cells made of Fig. 2 includes. DETAILED DESCRIPTION

[0005] The currently preferred compositions, embodiments, and methods of the present disclosure, which represent the best known practice to the inventors, are described. The figures are not necessarily drawn to scale. The disclosed embodiments are merely examples, and the disclosure may be realized in various alternative forms. Consequently, the specific details provided should not be considered limiting. Instead, they serve as a representative basis for understanding any aspect of the disclosure and as a guide for the person skilled in the art regarding how the present disclosure may be applied in various ways.

[0006] Unless expressly stated otherwise, if a given chemical structure includes a substituent on a chemical unit (e.g., on an aryl, alkyl, etc.), it is assumed that this substituent applies to a more general chemical structure that includes the given structure. Percentages, "parts of," and ratios are by weight. The term "polymer" includes "oligomer," "copolymer," "terpolymer," and similar structures. Molecular weights provided for any polymers are weight-average molecular weights unless otherwise stated. Where a group or class of materials is described as suitable or preferred for a given purpose in connection with the disclosure, this implies that mixtures of any two or more elements of the group or class are equally suitable or preferred.Descriptions of components using chemical terms refer to the components at the time of their addition to any given combination and do not necessarily exclude chemical interactions between the components once mixed. The first definition of an acronym or abbreviation applies to all subsequent uses of the same abbreviation and similarly to normal grammatical variants of the originally defined abbreviation. Unless explicitly stated otherwise, the measurement of a property is determined by the same technique previously or subsequently mentioned for the same property.

[0007] The singular forms "a," "an," and "the" used in the description and the appended claims include plural references unless the context clearly indicates otherwise. For example, a singular reference to a component is intended to include a plurality of components. Moreover, this disclosure is not limited to the specific embodiments and methods described herein, as specific components and / or conditions may vary. Furthermore, the terminology used herein is employed only for the purpose of describing certain embodiments of the present disclosure and is not intended to be restrictive in any way. The term "comprising" is synonymous with "including," "having," "containing," or "characterized by." These terms are inclusive and open, meaning that they do not exclude additional, unlisted elements or process steps.The phrase “composed of” means “containing” or “consisting of” and is typically used to indicate that an object is made of a given material.

[0008] Integer ranges explicitly include all integers in between. For example, the integer range 1–10 includes 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10. Similarly, the range 1–100 includes all integers from 1 to 100. Furthermore, if any range is specified, intermediate numbers that are increments of the difference between the upper and lower bounds divided by 10 can be considered as alternative upper or lower bounds. For example, if the range is 1.1 to 2.1, the numbers 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, and 2.0 can be chosen as alternative lower or upper bounds.

[0009] Unless expressly stated otherwise, all numerical values ​​and ranges relating to quantities, measurements, percentages, weights, and similar numerical statements herein are to be understood as being preceded by the phrase "approximately." This applies even if "approximately" is not explicitly mentioned. The intention is that all values ​​and ranges take into account variations that may arise from standard measurement techniques, manufacturing processes, material properties, and the intended functionality of the disclosed aspects. For example, if a composition is described as having "5 wt.% of a component," this is to be understood as "approximately 5 wt.% of a component." Moreover, if numerical values ​​are given as a range, such as "100 to 200 units," this range should be interpreted as "approximately 100 to approximately 200 units." These variations are implicitly included in the scope of this disclosure.

[0010] The term "positive electrode" refers to a battery cell electrode from which current flows during the discharge of a lithium-ion battery cell or battery. This electrode is sometimes called the "cathode." Conversely, the term "negative electrode" refers to a battery cell electrode into which current flows during the discharge of a lithium-ion battery cell. This electrode is sometimes called the "anode."

[0011] The term "cell" or "battery cell" refers to an electrochemical cell comprising at least one positive electrode, at least one negative electrode, an electrolyte, and a separator membrane. The term "battery" or "battery pack" refers to an electrical storage device comprising at least one battery cell. More precisely, a "battery" or "battery pack" is an electrical storage device composed of several battery cells.

[0012] The term “specific capacity” refers to the capacity per unit mass of the anode active material, measured in milliampere-hours per gram (mAh / g).

[0013] As previously mentioned, LMR active materials for positive electrodes represent a promising class of cathode materials for lithium-ion batteries, characterized by their high specific capacity and energy density. These materials are particularly suitable for applications requiring long range and high energy, such as electric vehicles and large-scale energy storage systems. A distinguishing feature of LMR materials is their high manganese content, which, due to the relative abundance of manganese, can make them more attractive than cobalt-rich counterparts. The structure of LMR materials is a composite of layered lithium (Li) transition metal oxides, in which additional Li ions are incorporated into the lattice. This composite structure can consist of layered LiMO₂ and Li₂MnO₃ components, offering a unique combination of electrochemical properties.LMR materials exhibit high specific capacities, often exceeding 180 mAh / g, due to the reversible redox reactions of both transition metals and lattice oxygen. They can be operated at high voltages, typically up to 4.5 V vs. gr, which contributes to their high energy density. The electrochemical activity of LMR materials involves not only the transition metal redox couples but also the participation of lattice oxygen, which undergoes reversible redox reactions.

[0014] The high capacity and high voltage of LMR materials can lead to superior energy density, making them attractive for applications requiring long-range, high-energy batteries. Their appeal is further enhanced by the use of manganese (Mn), a more abundant element than cobalt (Co). Additionally, manganese-based materials generally offer better heat resistance compared to cobalt-rich materials.

[0015] However, several challenges must be overcome for the practical application of LMR materials. One problem is stress decay, a gradual loss of stress over cycles that leads to a decrease in energy density over time. Structural changes over cycles, including transition metal migration and oxygen loss, can affect the long-term cycle stability of LMR materials. Furthermore, LMR materials often exhibit slower kinetics compared to conventional cathode materials, impacting their rate performance. Accordingly, there is a need for LMR material compositions for active materials for positive electrodes in lithium-ion batteries with increased rate capability, cell performance, and volumetric energy density.

[0016] The present disclosure provides compositions for LMR cathodes used in lithium-ion batteries.

[0017] In one or more embodiments, the LMR compositions have a specific lithium content optimized for performance. The compound is designated by the formula Li 1,01+a Mn 0,50+b Ni 0,25+c Co x O2 is represented, where 0 < a < 0.14, 0 ≤ b ≤ 0.10, 0 ≤ c ≤ 0.24 and 0 ≤ x ≤ 0.10. This modification aims to increase cycle performance, power performance and rate capability by increasing the voltage stability and the electronic and ionic conductivity of the LMR.

[0018] This controlled formation process targets aspects such as cycle performance, power efficiency, and rate capability. To address voltage decay, the LMR compositions can be fine-tuned to optimize lithium retention and structural stability across cycling stages. For example, the unrecovered lithium content in the cathode active material (CAM) can decrease to the range of 0.27 to 0.35 after the initial formation charge, which can stabilize the electrode structure. After the first formation discharge, the lithium content in the CAM can be in the range of 1.00 to 1.05, maintaining sufficient lithium for further cycling. After the second formation charge, the lithium content can be in the range of 0.30 to 0.38, ensuring continued electrode stability during high-voltage cycling.After the second formation discharge, the lithium content can return to a range of 1.00 to 1.05, thus maintaining capacity and long-term performance. The ratio of unrecovered lithium after the first formation charge to the lithium content after the second formation charge can be within a range of 0.70 to 0.93 to increase energy density and reduce degradation during cycling.

[0019] For applications requiring higher energy density and increased rate capability, the composition can be fine-tuned within specified ranges. For example, adjusting "a" between 0.00 and 0.14, "b" between 0.00 and 0.10, "c" between 0.00 and 0.24, and "x" between 0.00 and 0.01 maximizes electrochemical properties to meet specific performance requirements. These formulations are configured to support extended charge / discharge cycles under demanding conditions. The active material for positive electrodes can exhibit a specific capacity of at least 180 mAh / g.When used in a lithium-ion battery cell, this active material is combined with a negative electrode (often using graphite, silicon or a silicon-carbon composite as the active material) and an electrolyte containing lithium salts, such as lithium hexafluorophosphate, lithium tetrafluoroborate or lithium bis(trifluoromethanesulfonyl)imide in an organic solvent.

[0020] Referring to the Fig. 1A and Fig. Figure 1B provides a schematic representation of a positive electrode 10 incorporating a positive electrode active material. The positive electrode 10 includes a layer 12 of positive electrode active material arranged over and typically in contact with a current collector 14 of the positive electrode. Typically, the positive electrode current collector 14 is a metal plate or foil composed of a metal such as aluminum (Al), copper (Cu), platinum (Pt), zinc (Zn), titanium (Ti), and the like. Aluminum is also used for positive electrode current collectors. The positive electrode active material is represented by Equation 1: Li 1,01+a Mn 0,50+b Ni 0,25+c Co x O2 (1) where: 0 < a < 0.14, 0 ≤ b ≤ 0.10, 0 ≤ c ≤ 0.24 and 0 ≤ x ≤ 0.10.

[0021] Specific active compositions for electrodes can contain Li 1,01 Mn 0,50 Ni 0,48Co 0,01 O2, Li 1,05 Mn 0,52 Ni 0,42 Co 0,01 O2, Li 1,10 Mn 0,54 Ni 0,34 Co 0,02 O2, Li 1,12 Mn 0,55 Ni 0,30 Co 0,03 O2, Li 1,14 Mn 0,56 Ni 0,26 Co 0,04 O2, Li 1,08 Mn 0,58 Ni 0,28 Co 0,06 O2 and Li 1,11 Mn 0,59 Ni 0,25 Be CO0.

[0022] With reference to Fig. Figure 2 provides a schematic representation of a rechargeable lithium-ion battery cell 20. The rechargeable lithium-ion battery cell 20 includes the positive electrode 10, as described above, a negative electrode 22, and a separator 24 arranged between the positive electrode 10 and the negative electrode 22. The negative electrode 22 includes a negative electrode current collector 26 and a layer 28 of negative active material arranged above and typically in contact with the negative electrode current collector 26. Typically, the negative electrode current collector 26 is a metal plate or foil composed of metal, such as Al, Cu, Pt, Zn, Ti, and the like. Currently, copper is most commonly used for negative electrode current collectors.The rechargeable lithium-ion battery cell 20 is immersed in an electrolyte 30, which is enclosed by the battery cell housing 32. The electrolyte 30 is absorbed into the separator 24. In other words, the separator 24 contains the electrolyte 30, thus enabling Li-ions to move between the positive and negative electrodes 10, 22. The electrolyte 30 comprises a non-aqueous organic solvent and a Li-ion salt. The non-aqueous organic solvent serves as a medium for transferring ions involved in the electrochemical reaction of the rechargeable lithium-ion battery cell 20. Advantageously, the rechargeable lithium-ion battery cell 20 can have a specific capacity of more than 180 mAh / g.

[0023] Referring to Fig. Figure 3 provides a schematic representation of a rechargeable lithium-ion battery 40. The battery 40 includes at least one lithium-ion battery cell 20. i the design Fig. 2. Each of the lithium-ion battery cells 20 i includes the positive electrode 10, which contains the compound represented by formula 1, the negative electrode 22, which contains a negative active material, and the electrolyte 30, where i is an integer identifier for each of the lithium-ion battery cells 20 i The designation i ranges from 1 to nmax, where nmax is the total number of battery cells in the rechargeable lithium-ion battery 40. The electrolyte 30 comprises a non-aqueous organic solvent and a Li salt. The non-aqueous organic solvent serves as a medium for transferring ions involved in the electrochemical reaction of the battery 40. The battery cells 20i They can be wired in series, parallel, or a combination thereof. The voltage output from battery 40 is provided via terminals 42 and 44.

[0024] Referring to the Fig. 2 and Fig. 3. The separator 24 physically separates the negative electrode 22 from the positive electrode 10, thus preventing a short circuit while allowing the transport of Li ions for charging and discharging. Therefore, the separator 24 can be made of any material suitable for this purpose. Examples of suitable materials from which the separator 24 can be made include, among others, polytetrafluoroethylene (e.g., Teflon). ®), fiberglass, polyester, polyethylene, polypropylene, and combinations thereof. The separator 24 can be in the form of either a woven or nonwoven fabric. For example, a polyolefin-based polymer separator, such as polyethylene and / or polypropylene, is typically used for lithium-ion batteries. To ensure heat resistance or mechanical strength, a coated separator incorporates a ceramic coating or a polymer material may be used.

[0025] Electrolyte 30 contains a lithium salt dissolved in a non-aqueous organic solvent, as mentioned above. Therefore, electrolyte 30 contains lithium ions that can intercalate into the active material for positive electrodes during discharge and into the active material for negative electrodes during charging. Examples of lithium salts include, but are not limited to, LiPF6, LiBF4, LiSbF6, LiAsF6, LiC4F9SO3, LiClO4, LiAlO2, LiAlCl4, LiCl, LiI, LiB(C2O4)2, and combinations thereof. In one refinement, electrolyte 30 contains a lithium salt in an amount of approximately 0.1 M to approximately 2.0 M.

[0026] The non-aqueous organic solvent acts as a medium for transferring ions, particularly lithium ions, that participate in the electrochemical reactions within a battery. Suitable non-aqueous organic solvents include carbonate-based solvents, ester-based solvents, ether-based solvents, ketone-based solvents, alcohol-based solvents, aprotic solvents, and combinations thereof. Examples of carbonate-based solvents include dimethyl carbonate, diethyl carbonate, dipropyl carbonate, methylpropyl carbonate, ethylpropyl carbonate, methyl methyl carbonate, ethylene carbonate, propylene carbonate, butylene carbonate, and combinations thereof. Examples of ester-based solvents include methyl acetate, ethyl acetate, n-propyl acetate, methyl propionate, ethyl propionate, γ-butyrolactone, decanolide, valerolactone, mevalonolactone, caprolactone, and combinations thereof.Ether-based solvents include dibutyl ether, tetraglyme, diglyme, dimethoxyethane, 2-methyltetrahydrofuran, and tetrahydrofuran. Ketone-based solvents can include cyclohexanone. Alcohol-based solvents include methanol, ethanol, n-propyl alcohol, and isopropyl alcohol. Aprotic solvents include nitriles, such as R-CN (where R is a linear, branched, or cyclic C2-). 20 -hydrocarbon, which may contain a double bond, an aromatic ring or an ether bond), amides such as dimethylformamide, dioxolanes such as 1,3-dioxolane and sulfolanes.

[0027] The non-aqueous organic solvent can be used alone or as a mixture, typically formulated to optimize battery performance. In one refinement, a carbonate-based solvent is produced by blending a cyclic carbonate with a linear carbonate. Furthermore, the electrolyte may include vinylene carbonate or an ethylene carbonate-based compound to improve battery lifespan.

[0028] Negative and positive electrodes can be manufactured using methods well known to those skilled in the art in the field of lithium-ion batteries. Typically, an active material (either positive or negative) is mixed with a conductive material and a binder in a solvent, such as N-methylpyrrolidone. This mixture forms the active material composition, which is then applied to a current collector. Since the electrode manufacturing process is well established, no detailed descriptions are provided here. Although N-methylpyrrolidone is a commonly used solvent, other solvents may also be suitable for this process.

[0029] Layer 12 of the active material for positive electrodes comprises the active material for positive electrodes represented by formula 1, a binder, and a conductive material. The binder enhances the adhesion between the particles of the active material for positive electrodes and the current collector 14 of the positive electrode. Suitable binders include, but are not limited to, polyvinyl alcohol, carboxymethylcellulose, hydroxypropylcellulose, diacetylcellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene oxide-containing polymers, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, acrylate styrene-butadiene rubber, epoxy resin, nylon, and combinations thereof.

[0030] The conductive material provides electrical conductivity to the positive electrode. Suitable electrically conductive materials include natural graphite, synthetic graphite, carbon black (C), acetylene carbon black, Ketjen carbon black, carbon fibers, copper, metal powders, and metal fibers. Examples of metal powders and metal fibers include those composed of nickel, aluminum, silver (Ag), and combinations thereof.

[0031] With reference to Fig.2 The negative active material layer 28 comprises a negative active material, a binder, and optionally a conductive material. The negative active materials used in this document can be those negative materials known to those skilled in the art in the field of lithium-ion batteries. Negative active materials include, among others, carbon-based negative active materials, silicon-based (Si-based) negative active materials, and combinations thereof. Suitable carbon-based negative active materials can include graphite and graphene. Suitable silicon-based negative active materials can include at least one selected from silicon, silicon oxide, silicon oxide coated with conductive carbon on the surface, and silicon coated with conductive carbon on the surface. For example, silicon oxide can be represented by the formula SiO₂. zcan be described, where z is between 0.09 and 1.1. Mixtures of carbon-based or silicon-based negative active materials can also be used as the negative active material.

[0032] Layer 28, consisting of negative active material, comprises a negative active material, a binder, and optionally a conductive material. Suitable negative active materials for use in this context are well known to those skilled in the art in the field of lithium-ion batteries. These materials include, among others, carbon-based negative active materials, silicon-based negative active materials, and combinations thereof.

[0033] The binder of the negative electrode enhances the adhesion of particles of the negative active material to each other and to the current collector. The binder can be non-aqueous, aqueous, or a combination of both. Non-aqueous binders include polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene oxide-containing polymers, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamide-imide, polyimide, or combinations thereof. Aqueous binders can be rubber-based or polymer resin-based. Examples of rubber-based binders include styrene-butadiene rubber, acrylated styrene-butadiene rubber, acrylonitrile-butadiene rubber, acrylic rubber, butyl rubber, fluororubber, and combinations thereof.Polymer resin binders include polyethylene, polypropylene, ethylene-propylene copolymer, polyethylene oxide, polyvinylpyrrolidone, epichlorohydrin, polyphosphazene, polyacrylonitrile, polystyrene, ethylene-propylene diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, acrylic resin, phenolic resin, epoxy resin, polyvinyl alcohol and combinations thereof.

[0034] Although exemplary embodiments have been described above, it is not intended that these represent all possible forms of the disclosure. The language used in the description is descriptive and not limiting, and it is understood that various modifications can be made without deviating from the essence and scope of the disclosure. Furthermore, the features of different embodiments can be combined to create additional embodiments of the disclosure.

[0035] According to the present invention, an active material for positive electrodes for lithium-ion batteries is provided, comprising a compound defined by a general formula 1: Li 1,01+a Mn 0,50+b Ni 0,25+c Co x O2 (1) is represented where 0 < a < 0.14, 0 ≤ b ≤ 0.10, 0 ≤ c ≤ 0.24 and 0 ≤ x ≤ 0.10.

[0036] According to one embodiment, the active material for positive electrodes includes oxide, fluoride or phosphate.

[0037] According to one embodiment, one or more of the Mn, Ni, Co and O in the compound are partially substituted with a doping cation selected from the group consisting of magnesium, titanium, boron and aluminum.

[0038] According to one embodiment, one or more of the Mn, Ni, Co and O in the compound are partially substituted with a doping anion selected from the group consisting of fluorine and chlorine.

[0039] According to one embodiment, the particle size distribution of the active material for positive electrodes has a D50 value in the range of 1 µm to 20 µm.

[0040] According to one embodiment, the undriveted residual lithium content in the active material for positive electrodes after the first formation charge is between 0.27 and 0.35.

[0041] According to one embodiment, the lithium content in the active material for positive electrodes after the first formation charge is between 1.00 and 1.05.

[0042] According to one embodiment, the lithium content in the compound after the second forming charge is between 0.30 and 0.38.

[0043] According to one embodiment, the lithium content in the compound after the second formation discharge is between 1.00 and 1.05.

[0044] According to one embodiment, the ratio of unextracted residual lithium content after the first forming charge to the lithium content after the second forming charge is between 0.70 and 0.93.

[0045] According to the present invention, a positive electrode for a lithium-ion battery is provided, comprising an active material for positive electrodes, which includes a compound represented by chemical formula 1: Li 1,01+a Mn 0,50+b Ni 0,25+c Co x O2 (1) where: 0 < a < 0.14, 0 ≤ b ≤ 0.10, 0 ≤ c ≤ 0.24 and 0 ≤ x ≤ 0.10.

[0046] According to one embodiment, one or more of the Mn, Ni, Co and O in the compound are partially substituted with a doping cation selected from the group consisting of magnesium, titanium, boron and aluminum.

[0047] According to one embodiment, one or more of the Mn, Ni, Co and O in the compound are partially substituted with a doping anion selected from the group consisting of fluorine and chlorine.

[0048] According to one embodiment, the particle size distribution of the active material for positive electrodes has a D50 value between 1 µm and 20 µm.

[0049] According to one embodiment, the unrecovered residual lithium content in the positive electrode after the first forming charge is between 0.27 and 0.35.

[0050] According to one embodiment, the lithium content in the active material for positive electrodes after the first formation charge is between 1.00 and 1.05.

[0051] According to one embodiment, the lithium content in the active material for positive electrodes after the second forming charge is between 0.30 and 0.38.

[0052] According to one embodiment, the lithium content in the active material for positive electrodes after the second forming charge is between 1.00 and 1.05.

[0053] According to one embodiment, the ratio of unextracted residual lithium content after the first forming charge to the lithium content after the second forming charge is between 0.70 and 0.93.

[0054] According to the present invention, a rechargeable lithium-ion battery is provided, comprising at least one lithium-ion battery cell, each lithium-ion battery cell comprising: a positive electrode comprising a positive electrode active material as defined by Formula 1: Li 1,01+a Mn 0,50+b Ni 0,25+c Co x O2 (1) is represented where: 0 < a < 0.14, 0 ≤ b ≤ 0.10, 0 ≤ c ≤ 0.24 and 0 ≤ x ≤ 0.10, a negative electrode containing a negative active material; and an electrolyte.

Claims

[1] Active material for positive electrodes for lithium-ion batteries, comprising a compound represented by a general formula 1: Li 1,01+a Mn 0,50+b Ni 0,25+c Co x O2 (1) where: 0 <a<0,14, 0≤b≤0,10, 0≤c≤0.24 and 0≤x≤0,10. [2] Active material for positive electrodes according to claim 1, wherein the active material for positive electrodes comprises oxide, fluoride or phosphate. [3] Active material for positive electrodes according to claim 1, wherein one or more of the Mn, Ni, Co and O in the compound are partially substituted with a doping cation selected from the group consisting of magnesium, titanium, boron and aluminium. [4] Active material for positive electrodes according to claim 1, wherein one or more of the Mn, Ni, Co and O in the compound are partially substituted with a doping anion selected from the group consisting of fluorine and chlorine. [5] Active material for positive electrodes according to claim 1, wherein a particle size distribution of the active material for positive electrodes has a D50 value in the range of 1 µm to 20 µm. [6] Active material for positive electrodes according to claim 1, wherein the unextracted residual lithium content in the active material for positive electrodes after the first formation charge is between 0.27 and 0.

35. [7] Active material for positive electrodes according to claim 1, wherein the lithium content in the active material for positive electrodes after the first formation discharge is between 1.00 and 1.

05. [8] Active material for positive electrodes according to claim 1, wherein the lithium content in the compound after the second formation charge is between 0.30 and 0.

38. [9] Active material for positive electrodes according to claim 1, wherein the lithium content in the compound after the second formation discharge is between 1.00 and 1.

05. [10] Active material for positive electrodes according to claim 1, wherein the ratio of the unremoved residual lithium content after the first formation charge to the lithium content after the second formation charge is between 0.70 and 0.

93. [11] Positive electrode for a lithium-ion battery, which includes an active material for positive electrodes comprising a compound represented by chemical formula 1: Li 1,01+a Mn 0,50+b Ni 0,25+c Co x O2 (1) where: 0 <a<0,14,0≤b≤0,10,0≤c≤0,24 and 0≤x≤0,10. [12] Positive electrode according to claim 11, wherein one or more of the Mn, Ni, Co and O in the compound are partially substituted with a doping cation selected from the group consisting of magnesium, titanium, boron and aluminium. [13] Positive electrode according to claim 11, wherein one or more of the Mn, Ni, Co and O in the compound are partially substituted with a doping anion selected from the group consisting of fluorine and chlorine. [14] Positive electrode according to claim 11, wherein a particle size distribution of the active material for positive electrodes has a D50 value between 1 µm and 20 µm. [15] Rechargeable lithium-ion battery, comprising at least one lithium-ion battery cell, each lithium-ion battery cell comprising the following: a positive electrode comprising a positive electrode active material as represented by Formula 1: Li 1,01+a Mn0,50+b Ni 0,25+c Co x O2 (1) where: 0 <a<0,14,0≤b≤0,10, 0≤c≤0.24 and 0≤x≤0.10, a negative electrode that incorporates a negative active material; and an electrolyte.

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