Cathode active material having spinel nanocomposite structure for secondary battery and method thereof

Abstract

The positive electrode active material for a lithium secondary battery according to the present invention comprises a secondary particle composed of a plurality of primary particles, in which the primary particles comprise a nanocomposite in which a spinel (Fd3m) structure and a layered structure coexist in nanoscale. Although the spinel structure provides high structural stability, it has the disadvantage of low initial capacity. However, the positive electrode material of the present invention solves this limitation by introducing a nanocomposite structure in which a layered structure and a spinel structure are mixed in a nanoscale. Compared with a conventional single-structure positive electrode material, the innovation provides higher structural stability and improved electrochemical performance. By incorporating a spinel structure into the nanocomposite, the present invention enhances structural stability, minimizes deformation during charge-discharge cycles, while providing a three-dimensional lithium ion diffusion path. Therefore, faster lithium ion transmission is caused, and the rate capability and the high-rate charge-discharge performance are remarkably improved.

Description

Positive electrode active materials with spinel nanocomposite structures for secondary batteries and methods thereof.

[0001] Cross-references to related applications

[0002] This application claims priority and benefit to Korean Patent Application No. 10-2024-0152619 and Korean Patent Application No. 10-2025-0015772, filed with the Korean Intellectual Property Office on October 31, 2024 and February 7, 2025, respectively, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This invention relates to a positive electrode active material for lithium-ion secondary batteries, and more specifically, to a positive electrode active material with a nanocomposite structure for lithium-ion secondary batteries and a method for preparing the same, wherein the nanocomposite structure comprises a nanoscale mixture of spinel and layered structures. Background Technology

[0004] Lithium-ion rechargeable batteries possess high energy density and long lifespan, making them widely used in various electronic devices, electric vehicles, and energy storage systems (ESS). A key factor determining the performance of lithium-ion rechargeable batteries is the positive electrode active material, which is typically composed of transition metal oxides with a layered structure containing elements such as nickel (Ni), cobalt (Co), and manganese (Mn), or has a spinel structure.

[0005] Conventional high-nickel (high-Ni) cathode active materials can provide high capacity; however, they are structurally unstable during charge and discharge cycles, leading to capacity degradation and thermal deterioration. In particular, the layered structure undergoes significant structural deformation during cycling, making it susceptible to particle cracking. When particle cracking occurs, electrolyte permeation into the secondary particles leads to degradation of the inner and outer surfaces of the primary particles. This results in reduced electronic conductivity and increased interfacial resistance, significantly degrading battery performance.

[0006] To address these issues, the incorporation of spinel structures has been investigated. Spinel structures provide a three-dimensional lithium-ion diffusion path, improving conductivity and structural stability, thereby reducing deformation during charge and discharge cycles. However, relying solely on spinel structures may result in low initial capacity. Therefore, an optimal technique combining layered and spinel structures is needed to achieve superior performance.

[0007] Typically, spinel structures are considered traces of degradation in layered cathode materials. Spinel structures are thermodynamically more stable than layered structures and are formed due to the degradation of the cathode material, particularly on the surface of secondary particles in contact with the electrolyte. Summary of the Invention

[0008] The technical objectives of this disclosure are not limited to those described above, and those skilled in the art will clearly understand other unmentioned technical objectives from the following description.

[0009] This invention provides a nanocomposite positive electrode active material that enhances stability by doping with elements such as Mo, Ta and W, while also improving rate performance and lifetime characteristics.

[0010] The positive electrode active material for lithium-ion secondary batteries according to the present invention comprises secondary particles consisting of a set of primary particles, wherein the primary particles comprise nanocomposite materials, wherein the spinel (Fd3m) structure and layered structure are present. The structure is a nanoscale hybrid.

[0011] Typically, spinel structures are traces of degradation found in bands on the surface of primary particles in cathode materials after charge and discharge cycles. However, the spinel structure of the nanocomposite material according to the present invention is a structure observed in the initial state before the cathode material is put into operation, and is not a trace of degradation. Furthermore, the spinel structure is characterized by existing in the form of a nanocomposite material within the primary particles, rather than appearing in bands on the surface of the primary particles.

[0012] In addition, electron diffraction spots S(a, a, a+2) and S(b, b, b-2) can be observed in the SAED electron diffraction image.

[0013] S() represents spinel structure, while L() represents layered crystal structure.

[0014] Furthermore, in the SAED electron diffraction pattern, the diffraction peak intensities obtained from the L(0, -1, -2-3(m-1)) and S(a, a, a+2) planes satisfy the relationship I(L(0, -1, -2-3(m-1)))>I(S(a, a, a+2)). Similarly, the diffraction peak intensities obtained from the L(0, 1, 2+3(n-1)) and S(b, b, b-2) planes satisfy the relationship I(L(0, 1, 2+3(n-1)))>I(S(b, b, b-2)).

[0015] Furthermore, the maximum length passing through the center of the cross-section of the spinel structure region can range from 1 nm to 100 nm, and the cross-sectional area of ​​the spinel structure region can be 1 nm. 2 Up to 10000nm 2 Within the range.

[0016] Furthermore, nanocomposites can exist inside or on the surface of primary particles, or inside or on the surface of secondary particles.

[0017] Nanocomposite materials can be observed before the charge-discharge cycle of the positive electrode active material begins.

[0018] Furthermore, the nanocomposite material provides three-dimensional Li in the charged state. + Migration path, thereby improving the rate performance of the cathode material.

[0019] Furthermore, the nanocomposites observed before charge-discharge cycling may still be present in the charged state and after charge-discharge cycling. The nanocomposites found inside the primary particles after charge-discharge cycling are distinguishable from the spinel impurities formed on the surface of the secondary particles due to electrode degradation during charge-discharge cycling.

[0020] The primary particles of the positive electrode active material include nickel (Ni), M1, and M2, wherein M1 includes at least one of cobalt (Co), manganese (Mn), and aluminum (Al). The nickel (Ni) content is 50 mol% or more, and M2 is a dopant element with a content of 0.05 mol% to 10 mol%.

[0021] M2 may include one or more of the following: cobalt (Co), manganese (Mn), titanium (Ti), magnesium (Mg), tantalum (Ta), niobium (Nb), tungsten (W), molybdenum (Mo), antimony (Sb), tellurium (Te), tin (Sn), ruthenium (Ru), boron (B), hafnium (Hf), gallium (Ga), germanium (Ge), chromium (Cr), vanadium (V), copper (Cu), calcium (Ca), zinc (Zn), barium (Ba), strontium (Sr), aluminum (Al), and zirconium (Zr).

[0022] The positive electrode active material can be obtained by mixing the composite metal hydroxide A(OH)2 precursor with M2 and performing high-temperature heat treatment, wherein A can be one of Ni, Co, Mn or Al.

[0023] A general precursor or wet-doped precursor is mixed with a lithium source (e.g., lithium hydroxide (LiOH) or lithium carbonate (Li2CO3)) and subjected to a first pre-calcination at 450°C for 5 hours. Subsequently, the pre-calcined material is further mixed with a dry dopant (e.g., Nb2O5, Ta2O5) and then subjected to a second calcination at 750°C for 10 hours to produce the final positive electrode active material.

[0024] In addition, a two-step co-doping process can be applied, in which W and Al are co-doped in Li[Ni]. 0.87 Co 0.10 Al 0.03 The O2 precursor was first heat-treated with a mixture of lithium and aluminum (Al). After the first heat treatment, an additional dopant W was introduced, and a second heat treatment was performed.

[0025] Furthermore, after obtaining the wet-doped precursor, it is mixed with a lithium source (LiOH or Li2CO3) and a dopant (e.g., Nb2O5, Al2O3). Pre-calcination is carried out at 450°C for 5 hours, followed by main calcination at 700–900°C to produce the final cathode active material.

[0026] Alternatively, the positive electrode active material can be obtained by mixing an M2-doped composite metal hydroxide (M2-doped A(OH)2) precursor with a lithium source and performing high-temperature heat treatment, wherein A can be one of Ni, Co, Mn or Al.

[0027] Alternatively, a positive electrode active material can be obtained by mixing an M2-coated composite metal hydroxide (M2-coated A(OH)2) precursor with a lithium source and performing high-temperature heat treatment, wherein A can be one of Ni, Co, Mn or Al.

[0028] In addition, positive electrode active materials can be obtained by mixing lithium source and M2 with M2-doped A(OH)2 precursor or M2-coated A(OH)2 precursor, and then performing high-temperature heat treatment, wherein A can be one of Ni, Co, Mn or Al.

[0029] Furthermore, concentration gradients of Ni, Co, or Mn can form within the primary particles.

[0030] Furthermore, the positive electrode active material can be obtained through a two-step calcination process. In the first calcination step, at least one of the composite metal hydroxide A(OH)2 precursor and the wet-doped composite metal hydroxide A(OH)2 precursor is mixed with a lithium source and subjected to high-temperature heat treatment. In the second calcination step, a dry dopant is further introduced, followed by additional high-temperature heat treatment to complete the synthesis of the final positive electrode active material.

[0031] Spinel structures offer high structural stability but suffer from low initial capacity. However, the cathode active material of this invention proposes a nanocomposite cathode active material in which layered and spinel structures coexist at the nanoscale. Compared to conventional single-structure cathode materials, this achieves higher structural stability and improved electrochemical performance.

[0032] Furthermore, conventional high-nickel (high-Ni) layered structures can undergo structural collapse and degradation during charge-discharge cycling. In contrast, this invention introduces a nanocomposite structure incorporating a spinel structure, which enhances structural stability, minimizes deformation during cycling, and provides a three-dimensional lithium-ion diffusion path. This improves lithium-ion mobility, enhances rate performance, and enables high-speed charge-discharge performance.

[0033] Furthermore, the positive electrode active material of the present invention disperses the mechanical stress (strain) generated during charge-discharge cycles, thereby extending the electrode lifetime. In particular, doping with elements such as Mo, Ta, Sb, Nb, Ti, Zr, and W further enhances long-term cycle stability.

[0034] Furthermore, the cathode active material and its manufacturing method proposed according to the present invention can form a nanocomposite structure by combining wet and dry doping processes in conventional cathode material production methods. Compared with existing manufacturing methods, this allows for the efficient production of high-performance cathode active materials without requiring additional complex processing steps. Attached Figure Description

[0035] Figures 1 and 2 are TEM (transmission electron microscopy) images showing the properties of a cathode material with a layered and spinel nanocomposite structure according to this embodiment.

[0036] Figure 3 shows the diffraction peak intensities of the layered and spinel structures.

[0037] Figure 4 shows a Mo wet-doped [Ni] according to an embodiment of the present invention. 0.98 Co 0.01 Mn 0.01 SEM image of the (OH)2 precursor.

[0038] Figure 5 shows Mo wet-doped Li[Ni] 0.98 Co 0.01 Mn 0.01 TEM image of the crystal structure of O2.

[0039] Figure 6 shows Mo wet-doped Li[Ni] 0.98 Co 0.01 Mn 0.01 O2 and conventional Li[Ni 0.98 Co 0.01 Mn 0.01 Another TEM image of the crystal structure of O2.

[0040] Figure 7 shows Mo wet-doped Li[Ni] 0.98 Co 0.01 Mn 0.01 O2 and conventional Li[Ni 0.98 Co 0.01 Mn 0.01 XRD pattern of O2 crystal structure.

[0041] Figure 8 shows the Mo wet-doped Li[Ni] after 100 cycles. 0.98 Co 0.01 Mn 0.01TEM image of the crystal structure of O2.

[0042] Figure 9 shows the Mo wet-doped Li[Ni] after charging to 4.3V. 0.98 Co 0.01 Mn 0.01 TEM image of the crystal structure of O2.

[0043] Figures 10 and 11 show the two-step Ta-doped Li[Ni] 0.94 Co 0.04 Mn 0.02 O2 and conventional Li[Ni 0.94 Co 0.04 Mn 0.02 TEM image of the crystal structure of O2.

[0044] Figure 12 shows the [Ni] wet-coated [Ni] by Co. 0.9 Co 0.05 Mn 0.05 SEM image of the (OH)2 precursor.

[0045] Figure 13 shows the [Ni] wet-coated [Ni] by Co. 0.9 Co 0.05 Mn 0.05 TEM-EDS image of the (OH)2 precursor.

[0046] Figures 14 and 15 show Co wet-coated Li[Ni] 0.9 Co 0.05 Mn 0.05 O2 and conventional Li[Ni 0.9 Co 0.05 Mn 0.05 TEM image of the crystal structure of O2.

[0047] Figure 16 shows Co wet-coated Li[Ni] 0.9 Co 0.05 Mn 0.05 TEM-EDS image of O2 cathode material.

[0048] Figure 17 shows Co wet-doped Li[Ni] 0.9 Co 0.05 Mn 0.05 O2 and conventional Li[Ni 0.9 Co 0.05 Mn 0.05 XRD pattern of O2 crystal structure.

[0049] Figures 18 and 19 illustrate the gradient Li[Ni] scalars produced by dry Sb doping. 0.9 Co 0.05 Mn 0.05O2 and conventional gradient Li[Ni 0.9 Co 0.05 Mn 0.05 TEM image of the crystal structure of O2.

[0050] Figures 20 and 21 show Ti wet-doped and Mo dry-doped Li[Ni] esters. 0.88 Co 0.06 Mn 0.06 O2 and conventional Li[Ni 0.88 Co 0.06 Mn 0.06 TEM image of the crystal structure of O2.

[0051] Figure 22 shows Ti wet-doped and Mo dry-doped Li[Ni] esters. 0.88 Co 0.06 Mn 0.06 O2 and conventional Li[Ni 0.88 Co 0.06 Mn 0.06 XRD pattern of O2 crystal structure.

[0052] Figures 23 and 24 show Ta and Al dry co-doped Li[Ni] according to one embodiment. 0.89 Co 0.1 Al 0.01 O2 and conventional Li[Ni 0.89 Co 0.1 Al 0.01 TEM image of the crystal structure of O2.

[0053] Figures 25 and 26 show the two-step co-doping of Li[Ni] with W and Al. 0.87 Co 0.10 Al 0.03 O2 and conventional Li[Ni 0.87 Co 0.10 Al 0.03 TEM image of the crystal structure of O2.

[0054] Figures 27 and 28 illustrate W wet and Ti dry co-doped Li[Ni] according to one embodiment. 0.91 Mn 0.09 O2 and conventional Li[Ni 0.91 Mn 0.09 TEM image of the crystal structure of O2.

[0055] Figure 29 shows a Co wet-coated [Ni] according to one embodiment. 0.7 Co 0.1 Mn 0.2 SEM image of the (OH)2 precursor.

[0056] Figures 30 and 31 show Co wet-coated and W dry-doped Li[Ni] slurries. 0.7 Co 0.1 Mn 0.2 O2 and conventional Li[Ni 0.7 Co 0.1 Mn 0.2 TEM image of the crystal structure of O2.

[0057] Figures 32 and 33 show the gradient Li[Ni] co-doped with W and Zr by dry process. 0.7 Co 0.05 Mn 0.25 O2 and conventional gradient Li[Ni 0.7 Co 0.05 Mn 0.25 TEM image of the crystal structure of O2.

[0058] Figures 34 and 35 show the two-step Mo-doped Li[Ni] tandem. 0.6 Mn 0.4 O2 and conventional Li[Ni 0.6 Mn 0.4 TEM image of the crystal structure of O2.

[0059] Figure 36 shows Li[Ni] 2-step Mo doping. 0.6 Mn 0.4 O2 and conventional Li[Ni 0.6 Mn 0.4 XRD pattern of O2 crystal structure. Detailed Implementation

[0060] Exemplary embodiments of the invention will be described with reference to the accompanying drawings, through which the object, configuration, and features of the invention will be well understood.

[0061] The positive electrode active material according to the present invention comprises secondary particles consisting of a set of primary particles. The primary particles contain a nanocomposite material in which a spinel (Fd3m) structure and layering are present. The structures coexist at the nanoscale.

[0062] In one embodiment of the invention, the nanocomposite structure comprises a mixture of spinel and layered structures within the primary particles, and characteristic peaks of both structures are simultaneously detected in a SAED electron diffraction pattern. In this case, the cross-sectional area of ​​the spinel structure is 1 nm. 2 Up to 10000nm 2 And the maximum length is 1nm to 100nm.

[0063] The main components of the transition metal composition include a composite metal oxide (Li[Ni]) containing nickel (Ni), cobalt (Co) and manganese (Mn). x Co y Mn z [O2, where 0.6≤x≤0.98, 0≤y≤0.2, 0≤z≤0.4]. Other doping elements (such as Mo, Ta, W, Al, Ti and Zr) can be introduced in the range of 0.05mol% to 10mol% to enhance stability and performance.

[0064] The positive electrode active material according to one embodiment of the present invention provides a three-dimensional lithium-ion diffusion pathway (3D Li) in electrochemical applications. + The diffusion pathway improves rate performance and significantly extends cycle life by minimizing structural collapse during charge-discharge cycles. Furthermore, it exhibits superior high-temperature stability compared to conventional monolayer cathode materials.

[0065] Furthermore, in the SAED electron diffraction pattern, electron diffraction spots S(a, a, a+2) and S(b, b, b-2) can be observed. Additionally, in the SAED electron diffraction pattern, the diffraction peak intensities of the L(0, -1, -2-3(m-1)) and S(a, a, a+2) planes satisfy the relationship I(L(0, -1, -2-3(m-1)))>I(S(a, a, a+2)). Similarly, the diffraction peak intensities of the L(0, 1, 2+3(n-1)) and S(b, b, b-2) planes satisfy I(L(0, 1, 2+3(n-1)))>I(S(b, b, b-2)). For example, I(L(0, -1, -2))>I(S(-1, -1, 1)) and I(L(0, 1, 2))>I(S(1, 1, -1)).

[0066] Furthermore, the nanocomposite material according to the present invention can exist inside or on the surface of primary particles, or it can be located inside or on the surface of secondary particles. The nanocomposite material can be observed before the start of charge-discharge cycling of the positive electrode active material. It provides three-dimensional Li in the charged state. + Migration pathways are established, thereby improving the rate performance of the cathode material. Nanocomposites observed before charge-discharge cycling can also be found in the charged state and after cycling. Furthermore, the nanocomposites found in the primary particles after cycling can be distinguished from the spinel impurities formed on the surface of secondary particles due to cathode degradation during charge-discharge cycling.

[0067] The precursor, mixed with lithium, undergoes heat treatment to form the cathode material, during which a nanocomposite structure is generated. In this process, the cathode active material can be obtained by mixing the composite metal hydroxide A(OH)2 precursor with M2 and subjecting it to high-temperature heat treatment, wherein A can be Ni, Co, Mn, or Al.

[0068] Furthermore, the positive electrode active material can be obtained by mixing an M2-doped composite metal hydroxide (M2-doped A(OH)2) precursor with a lithium source and then performing high-temperature heat treatment. Another method includes mixing an M2-coated composite metal hydroxide (M2-coated A(OH)2) precursor with a lithium source and then performing high-temperature heat treatment. Alternatively, the positive electrode active material can be obtained by mixing an M2-doped A(OH)2 precursor or an M2-coated A(OH)2 precursor with a lithium source and additional M2, followed by high-temperature heat treatment. A concentration gradient of Ni, Co, or Mn can also be formed within the primary particles.

[0069] Next, doping or coating can be performed. Specifically, the desired cathode material can ultimately be produced by doping or wet coating methods using M2. This allows for control over the desired electrochemical properties.

[0070] M2 refers to the specific metallic element used as a dopant element in this invention, which includes not only nickel (Ni), cobalt (Co), and manganese (Mn), but also titanium (Ti), magnesium (Mg), tantalum (Ta), niobium (Nb), tungsten (W), molybdenum (Mo), antimony (Sb), tellurium (Te), tin (Sn), ruthenium (Ru), boron (B), hafnium (Hf), gallium (Ga), germanium (Ge), chromium (Cr), vanadium (V), copper (Cu), calcium (Ca), zinc (Zn), barium (Ba), strontium (Sr), aluminum (Al), and zirconium (Zr).

[0071] The concentration of M2 ranges from 0.05 mol% to 10 mol%, which enhances the properties of the positive electrode active material. Through doping, the electrochemical performance is optimized, and the ionic conductivity is increased.

[0072] [A method for manufacturing a positive electrode active material according to one embodiment]

[0073] A detailed description of a method for manufacturing a positive electrode active material according to one embodiment of the present invention is provided. The positive electrode active material in this embodiment can be produced by a doping and calcination step using a composite metal hydroxide precursor (A(OH)₂, where A = Ni, Co, Mn).

[0074] For example, composite metal hydroxide precursors can be synthesized via a coprecipitation process. To this end, nickel sulfate (NiSO4·6H2O), cobalt sulfate (CoSO4·7H2O), and manganese sulfate (MnSO4·H2O) were mixed at a target molar ratio (x:y:z) to prepare a 2.5 M metal ion solution. This prepared metal ion solution was injected into a 500 L coprecipitation reactor using distilled water, while nitrogen (N2) was supplied at a flow rate of 150 L / min, and the mixture was stirred at 50 °C.

[0075] During pH control and the coprecipitation reaction, the pH of the solution was maintained within the range of 10 to 12 using 20M ammonia solution (NH4OH) and 6M sodium hydroxide solution (NaOH). This ensured the stable progress of the coprecipitation reaction, which was carried out for 20 hours with stirring at 250 rpm to synthesize the metal hydroxide precursor. The synthesized precursor was filtered to remove impurities, and then washed multiple times to remove residual solvent and reaction byproducts. The final precursor powder was obtained by vacuum drying at 110 °C for 8 hours.

[0076] The synthesized precursors undergo doping and coating processes to enhance their performance.

[0077] wet doping process

[0078] In wet doping methods, a dopant solution containing elements such as Mo, Ta, Ti, Sb, or W is added to the precursor to ensure a uniform distribution of each specific element. In this process, additional ammonia and sodium hydroxide solutions are introduced to promote uniform dispersion of the dopant. After the reaction is complete, the doped precursor undergoes drying and grinding to obtain the final doped material.

[0079] Dry doping process

[0080] In the dry doping method, a dried precursor is mixed with a lithium source (LiOH or Li₂CO₃). Furthermore, a solid dopant (such as MoO₃, WO₃, Al(OH)₃, TiO₂, Zr₂O₃, Nb₂O₅, or Ta₂O₅) is mixed and uniformly ground. This optimizes the chemical composition of the precursor, ensuring a uniform structure when it is finally sintered into the positive electrode active material.

[0081] Calcination and post-processing

[0082] After doping or coating, the final positive electrode active material is produced through calcination and post-processing.

[0083] First, the precursor was mixed with a lithium source and pre-calcined at 450°C for 5 hours at a heating rate of 2°C / min. This pre-calcination step stabilized the structure of the precursor and removed impurities.

[0084] During the main sintering process, the pre-calcined materials are further mixed to obtain the target composition, and then calcined at a high temperature of 680–750 °C for 10 hours. In this step, the composite metal hydroxide precursor undergoes crystallization to form a spinel layered nanocomposite structure.

[0085] Following calcination, a post-processing step is performed. This involves a grading process to control particle size and achieve uniform distribution. Additionally, a wet coating method can be applied, using materials such as Co(OH)₂ or Al₂O₃ for the surface coating. This surface coating enhances the electrochemical stability of the cathode active material and improves its long-term cycling performance.

[0086] However, the method for manufacturing the positive electrode active material according to the present invention is not limited to the above-described process, and various alternative manufacturing methods can be applied. The following sections describe alternative production methods based on different embodiments.

[0087] 1. Synthesis of complex metal hydroxide precursors via co-precipitation

[0088] This embodiment describes a method for synthesizing a composite metal hydroxide precursor containing Ni, Co, and Mn using a co-precipitation process. For example, nickel sulfate (NiSO4·6H2O), cobalt sulfate (CoSO4·7H2O), and manganese sulfate (MnSO4·H2O) are mixed in a molar ratio of Ni:Co:Mn = 90:5:5 to prepare a 2.5 M metal solution.

[0089] A 500L co-precipitation reactor was filled with distilled water, and N2 gas was supplied at a flow rate of 150L / min while stirring at 250rpm at 50°C. Over 20 hours, a metal solution (40L / hr), a 20M ammonia solution (4.5L / hr), and a 6M NaOH solution (25L / hr) were continuously introduced into the reactor, maintaining the pH within the range of 10-12 to promote the synthesis of the complex metal hydroxide.

[0090] The synthesized precursor was filtered and washed to remove impurities, and then dried under vacuum at 110°C for 8 hours to obtain the precursor in powder form.

[0091] 2. Synthesis of concentration gradient complex metal hydroxide precursors

[0092] This embodiment describes a method for producing a concentration-gradient composite metal hydroxide precursor in which the core and surface regions have different compositions. During the co-precipitation synthesis stage, the composition of the metal ion solution is gradually adjusted to produce a nickel-rich core (e.g., Ni:Co:Mn = 100:0:0) and a surface region containing Co and Mn (e.g., Ni:Co:Mn = 80:10:10).

[0093] This controlled compositional gradient enables a gradual transition of the transition metal composition in the precursor. Compared to conventional materials, the synthesized precursor reduces internal stress during charge-discharge cycles, thereby improving the long-term cycling stability of the final cathode material.

[0094] 3. Synthesis of doped precursors through heterogeneous element doping

[0095] This embodiment describes a method for enhancing the structural stability of cathode active materials by doping with elements such as Mo, W, Sb, Ti, Zr, and Ta. Based on the precursor synthesized in Example 1 or Example 2, a doped precursor is prepared by adding one or more doping elements (Mo, W, Ta) to a metal solution at a concentration of 0.05-10 mol% during a co-precipitation reaction.

[0096] Once the reaction is complete, the dopant precursor is obtained through filtration, washing, and drying to ensure uniform doping of the dopant element.

[0097] 4. Two-step doping and wet + dry co-doping processes

[0098] This manufacturing embodiment employs a two-step doping process to ensure that the dopant is uniformly distributed in the positive electrode active material.

[0099] Two-step doping process

[0100] The conventional two-step doping method uses a general precursor. The general precursor or wet-doped precursor is mixed with a lithium source (e.g., lithium hydroxide (LiOH) or lithium carbonate (Li₂CO₃)) and subjected to a first pre-calcination at 450°C for 5 hours. Subsequently, the pre-calcined material is further mixed with a dry dopant (e.g., Nb₂O₅, Ta₂O₅) and then subjected to a second calcination at 750°C for 10 hours to produce the final positive electrode active material.

[0101] For two-step co-doping (e.g., W and Al two-step co-doping of Li[Ni]), 0.87 Co 0.10 Al 0.03 First, the precursor is mixed with lithium and aluminum and subjected to an initial heat treatment. Then, another dopant (e.g., W) is introduced into the material after the initial heat treatment, followed by a second heat treatment to complete the doping process.

[0102] Wet + Dry Co-doping Process

[0103] A combination of wet doping and dry doping can also be used:

[0104] First, the wet-doped precursor obtained in Example 3 was prepared. It was then mixed with a lithium source (LiOH or Li₂CO₃) and other dopants (e.g., Nb₂O₅, Al₂O₃, etc.). Pre-calcination was performed at 450°C for 5 hours. Subsequently, main calcination was carried out at 700–900°C to produce the final positive electrode active material.

[0105] This co-doping strategy enhances the electrochemical performance and structural stability of the cathode material, ensuring optimal lithium-ion diffusion and cycle stability.

[0106] 5. Synthesis of precursors for cobalt wet coating

[0107] This embodiment describes a method for improving the conductivity and structural stability of a positive electrode active material by adjusting the cobalt (Co) content through wet coating.

[0108] A composite metal hydroxide precursor synthesized via a co-precipitation reaction was used. The precursor surface was coated with Co(OH)₂ using a wet coating method. The coating step involved adding ammonia (NH₄OH), cobalt sulfate (CoSO₄), and sodium hydroxide (NaOH) solutions to the reaction vessel to ensure uniform Co(OH)₂ deposition on the precursor surface. The coated precursor was then filtered and dried to obtain a wet-coated precursor with a uniform Co(OH)₂ layer.

[0109] 6. Dry doping of precursors for cobalt wet coating

[0110] This embodiment describes a method to further enhance the performance of the cobalt wet-coated precursor synthesized in Example 5 by applying an additional dry doping process. The wet-coated precursor is mixed with a lithium source (LiOH or Li₂CO₃) and a dopant (such as Nb₂O₅ or Ta₂O₅). Pre-calcination is performed at 450°C for 5 hours to stabilize the structure. Subsequently, main calcination is carried out at 700–900°C to complete the formation of the final cathode active material. This two-step process (wet coating + dry doping) improves the electrochemical stability, conductivity, and cycle performance of the cathode material.

[0111] 7. Dry doping for high-temperature stability

[0112] This embodiment describes a method for improving the high-temperature stability of cathode active materials through dry doping. A composite metal hydroxide was mixed with lithium hydroxide (LiOH) and Ta₂O₅ (Aldrich, 3N) at a molar ratio of (Ni+Co+Mn):Ta:Li = 0.995:0.005:1.01. The mixture was heated at a heating rate of 2 °C / min and pre-calcined at 450 °C for 5 hours. A main calcination was then performed at 700–900 °C to complete the doping process.

[0113] 8. Dry co-doping

[0114] This embodiment describes a dry co-doping method that utilizes multiple dopants to further optimize performance. A composite metal hydroxide is mixed with lithium hydroxide (LiOH), aluminum hydroxide (Al(OH)3, Aldrich, 3N), and molybdenum trioxide (MoO3, Aldrich, 3N) at a molar ratio of (Ni+Co+Mn):Al:Mo:Li = 0.985:0.01:0.005:1.01. The process follows the same procedure as in Example 7, including pre-calcination at 450°C for 5 hours and main calcination at 700–900°C.

[0115] The synthesis methods described in these embodiments aim to form spinel layered nanocomposite structures to optimize the performance of lithium-ion secondary batteries. Compared with conventional cathode active materials, the materials synthesized using these methods exhibit enhanced long-term cycle stability, high-rate charge / discharge performance, high-temperature stability, and high-voltage operation capability.

[0116] Figures 1 and 2 are TEM (transmission electron microscopy) images showing the properties of the layered and spinel nanocomposite cathode material according to this embodiment.

[0117] Referring to Figures 1 and 2, the cathode material with a layered and spinel nanocomposite crystal structure exhibits a unique SAED (selected area electron diffraction) pattern. Specifically, in addition to the layered... In addition to the electron diffraction spots, a spinel (Fd3m) structural pattern was also observed. This indicates that the cathode material according to this embodiment possesses both layered and spinel structural characteristics.

[0118] In other words, the cathode material of the present invention is a nanocomposite material, wherein the layered structure... The structure coexists with both the crystalline structure and the spinel (Fd3m) structure. The combination of these two structural characteristics significantly enhances the performance of lithium-ion batteries.

[0119] Furthermore, in this embodiment, the SAED pattern of the cathode material shows a layered structure corresponding to

[100] . and Electron diffraction spots of spinel (Fd3m) structure.

[0120] The coexistence of these two structures helps improve the electrical and chemical properties of the cathode material. In particular, lithium-ion mobility is enhanced, thereby improving electrochemical performance. These properties play a crucial role in extending battery life and increasing capacity.

[0121] Figure 3 shows the diffraction peak intensities of the layered and spinel structures.

[0122] Referring to Figure 3, S(a, a, a+2) and S(b, b, b-2) represent diffraction spots at specific coordinates in the SAED pattern. No diffraction spots corresponding to S(a, a, a+2) and S(b, b, b-2) were observed in the

[100] direction.

[0123] In layered In the TEM image of the spinel (Fd3m) nanocomposite, it was observed that and In summary, the relation L(0, -1, -2 - 3(m - 1)) > S(a, a, a + 2) can be derived from... Establish, and similarly, L(0, 1, 2 + 3(m - 1)) > S(b, b, b - 2) can be obtained from Export.

[0124] This means that the diffraction peak intensity of the layered structure is stronger than that of the spinel structure.

[0125] The following sections describe the evaluation results of various cathode materials with the following compositions, tested at 2.7–4.3 V and 30 °C.

[0126] [Nickel-rich NCM cathode material]

[0127] Mo wet-doped Li[Ni] 0.98 Co 0.01 Mn 0.01 O2

[0128] Ta-doped Li[Ni] 0.94 Co 0.04 Mn 0.02 O2

[0129] Co wet-coated Li[Ni] 0.9 Co 0.05 Mn 0.05 O2

[0130] Sb dry doping concentration gradient Li[Ni 0.9 Co 0.05 Mn 0.05 O2

[0131] Ti wet and Mo dry co-doped Li[Ni] 0.88 Co 0.06 Mn 0.06 O2

[0132] Mo wet-doped Li[Ni] 0.98 Co 0.01 Mn 0.01[Description of O2-rich nickel-NCM cathode material]

[0133] Referring to Figures 4 to 9, the wet-doped Li[Ni] is described. 0.98 Co 0.01 Mn 0.01 Characteristics of O2 (a nickel-rich NCM cathode material).

[0134] Figure 4: Mo wet-doped Li[Ni] according to an embodiment of the present invention 0.98 SEM image of the Co0.01Mn0.01]O2 precursor. Figure 5: Showing Mo wet-doped Li[Ni 0.98 Co 0.01 Mn 0.01 TEM image of the crystal structure of O2. Figure 6: Showing Mo wet-doped Li[Ni] 0.98 Co 0.01 Mn 0.01 O2 and conventional Li[Ni 0.98 Co 0.01 Mn 0.01 Another TEM image of the crystal structure of O2. Figure 7: Showing Mo wet-doped Li[Ni] 0.98 Co 0.01 Mn 0.01 O2 and conventional Li[Ni 0.98 Co 0.01 Mn 0.01 XRD pattern of the crystal structure of O2. Figure 8: Showing the wet-doped Li[Ni] by Mo after 100 cycles. 0.98 Co 0.01 Mn 0.01 TEM image of the crystal structure of O2. Figure 9: Showing Mo wet-doped Li[Ni] after charging to 4.3V. 0.98 Co 0.01 Mn 0.01 TEM image of the crystal structure of O2.

[0135] (Structural characteristics)

[0136] As shown in Figure 4, the Mo wet-doped NCM980101 precursor is spherical with a particle size of approximately 10 μm in diameter.

[0137] As shown in Figure 5, the SAED pattern confirms the coexistence of layered and spinel structures. HR-TEM observations revealed that the layered and spinel structures are intertwined, forming a layered-spinel nanocomposite structure. FT patterns corresponding to different regions further confirm the existence of different layered and spinel structures.

[0138] (Comparison with conventional cathode materials)

[0139] Referring to Figure 6, Mo wet-doped Li[Ni] 0.98 Co 0.01 Mn 0.01 O2 and control cathode (Li[Ni) 0.98 Co 0.01 Mn 0.01 O2) in Diffraction peaks were observed at L(000) and L(012), confirming the layered structure. However, this was only observed in the wet-doped Mo cathode. and The peak at the location indicates the presence of both layered and spinel structures in this invention, whereas only a layered structure was found in the comparative example.

[0140] Referring to Figure 7 and Table 1, compared with conventional layered cathodes, the ratio of I(003) / I(104), representing the degree of layered structure formation, is reduced in the spinel nanocomposite structure. This confirms the effectiveness of Mo wet-doped Li[Ni] 0.98 Co 0.01 Mn 0.01 O2 exhibits a mixed layered and spinel nanocomposite structure.

[0141] Chemical composition analysis

[0142] Table 1 presents the Mo wet-doped Li[Ni] 0.98 Co 0.01 Mn 0.01 O2 and conventional Li[Ni 0.98 Co 0.01 Mn 0.01 The chemical composition of O2 was determined by ICP-OES analysis.

[0143] [Table 1]

[0144]

[0145] By examining Tables 2 and 3, we can observe the wet-doped Li[Ni] by Mo. 0.98 Co 0.01 Mn 0.01 The cycle life characteristics and rate performance of O2 have been significantly improved.

[0146] [Table 2]

[0147]

[0148] [Table 3]

[0149]

[0150] Enhanced rate performance and structural stability

[0151] 3D Li + The formation of diffusion pathways (a key feature of spinel structures) significantly improves the wet-doped Li[Ni] silane. 0.98 Co 0.01 Mn 0.01 Rate performance of O2 cathode material.

[0152] By analyzing Figure 8 (TEM image after 100 cycles) and Figure 9 (TEM image after charging to 4.3V), it is clear that the spinel and layered structure that existed before cycling are still well preserved in the cathode material even after multiple cycles.

[0153] Comparison with conventional layered cathodes

[0154] Generally, layered cathode materials tend to degrade after cycling or in a charged state, during which the surface layered structure of the particles transforms into a spinel or rock salt phase. This degradation occurs due to the interaction between the cathode material and the electrolyte, resulting in the formation of a degraded surface layer on the primary particles.

[0155] However, in the layered and spinel nanocomposite structure of the present invention, the spinel structure remains well-preserved within the particles even after 100 cycles. Since the spinel phase does not form on the cathode surface, this structure does not indicate degradation, but rather improved structural stability of the cathode material. The pre-formed spinel structure remains intact throughout the cycling process, resulting in an overall improvement in cycle life characteristics.

[0156] Furthermore, the presence of the spinel structure provides 3D Li + The diffusion pathway improves lithium-ion mobility during charging and discharging. The formation of spinel structures in the charged state helps improve the rate performance of the cathode material, making it more suitable for high-power applications.

[0157] Ta-doped Li[Ni] 0.94 Co 0.04 Mn 0.02 [Description of O2-rich nickel-NCM cathode material]

[0158] Referring to Figures 10 and 11, the two-step Ta-doped Li[Ni] is described. 0.94 Co 0.04 Mn 0.02 Structural characteristics of O2 (a nickel-rich NCM cathode material). Figure 10: Showing Ta-doped Li[Ni] 0.94 Co 0.04 Mn 0.02TEM image of the crystal structure of O2. Figure 11: Showing Ta-doped Li[Ni] 0.94 Co 0.04 Mn 0.02 O2 and conventional Li[Ni 0.94 Co 0.04 Mn 0.02 Another TEM image of the crystal structure of O2.

[0159] (Structural characteristics)

[0160] As shown in Figure 10, the SAED pattern confirms the coexistence of layered and spinel structures. HR-TEM observations further reveal that the layered and spinel structures are intertwined, forming a layered and spinel nanocomposite structure. FT patterns corresponding to different regions confirm the existence of different layered and spinel phases.

[0161] Referring to Figure 11, Ta-doped Li[Ni] 0.94 Co 0.04 Mn 0.02 O2 and control cathode (Li[Ni) 0.98 Co 0.01 Mn 0.01 O2) in Diffraction peaks were observed at L(000) and L(012), confirming the layered structure. However, only in the Ta-doped cathode did diffraction peaks appear. and The observed peak indicates the presence of a layered and spinel structure, which is not present in the comparative example.

[0162] (Chemical composition and performance evaluation)

[0163] Table 4 presents the Ta-doped Li[Ni]2-step do ... 0.94 Co 0.04 Mn 0.02 O2 and conventional Li[Ni 0.94 Co 0.04 Mn 0.02 The chemical composition of O2 is shown in Table 5. Table 5 illustrates the cycle life characteristics, demonstrating improved capacity retention compared to conventional cathodes over extended charge-discharge cycles. Table 6 evaluates the rate performance, showing that the Ta-doped cathode material exhibits enhanced lithium-ion transport and maintains high discharge capacity at increased charge-discharge rates.

[0164] [Table 4]

[0165]

[0166] As shown in Figure 7, the presence of the spinel nanocomposite structure leads to a similar I(003) / I(104) ratio, indicating a reduction in the formation of layered crystal structures compared to conventional cathode materials. This confirms that the incorporation of the spinel phase into the layered structure affects the overall crystallinity, resulting in a lower I(003) / I(104) ratio than that of the standard layered cathode.

[0167] [Table 5]

[0168]

[0169] The formation of layered and spinel nanocomposite crystal structures effectively disperses the strain forces that typically develop in the layered crystal structures of nickel-rich cathodes during charge-discharge cycles. This strain relaxation significantly improves cycle life characteristics, indicating that the nanocomposite structure enhances the structural stability of the cathode material, thereby preventing rapid degradation and extending battery life.

[0170] [Table 6]

[0171]

[0172] In the Ta two-step doping of Li[Ni] according to this implementation scheme 0.94 Co 0.04 Mn 0.02 In the case of O2, 3D Li + The formation of diffusion pathways (a key feature of the spinel structure) significantly improves rate performance. This structural advantage facilitates more efficient lithium-ion transport, enabling the cathode material to maintain higher discharge capacity at high charge-discharge rates, thereby enhancing its overall electrochemical performance.

[0173] Co wet-coated [Ni] 0.9 Co 0.05 Mn 0.05 [Description of (OH)2 precursor and its cathode material]

[0174] Referring to Figures 12 to 17, the wet coating of Co with [Ni] is described. 0.9 Co 0.05 Mn 0.05 Characteristics of (OH)2 precursor and its derived cathode materials.

[0175] Figure 12: Co wet-coated [Ni] 0.9 Co 0.05 Mn 0.05 SEM image of the [(OH)2 precursor]. Figure 13: Co wet-coated [Ni] 0.9 Co 0.05 Mn0.05 Cross-sectional TEM-EDS images of the (OH)₂ precursor. Figures 14 and 15: Showing Co wet-coated Li[Ni] 0.9 Co 0.05 Mn 0.05 O2 and conventional Li[Ni 0.9 Co 0.05 Mn 0.05 TEM image of the crystal structure of O2. Figure 16: Co wet-coated Li[Ni] 0.9 Co 0.05 Mn 0.05 TEM-EDS image of O2 cathode material. Figure 17: Showing Co wet-coated Li[Ni] 0.9 Co 0.05 Mn 0.05 O2 and conventional Li[Ni 0.9 Co 0.05 Mn 0.05 XRD pattern of O2 crystal structure.

[0176] (Structural characteristics)

[0177] As shown in Figure 12, Co wet-coated [Ni] 0.9 Co 0.05 Mn 0.05 The (OH)2 precursor is spherical with a particle size of about 10 μm in diameter.

[0178] Referring to Figure 13, Co wet-coated Li[Ni] 0.9 Co 0.05 Mn 0.05 TEM-EDS analysis of the cross-section of the O2 precursor revealed a clearly discernible Co coating on the particle surface, confirming the uniform distribution of the coating.

[0179] Examine the Co wet-coated Li[Ni] in Figure 14 0.9 Co 0.05 Mn 0.05 TEM images of O2 and SAED patterns confirm the simultaneous presence of layered and spinel structures.

[0180] Furthermore, HR-TEM analysis revealed that layered and spinel structures are intertwined, forming a hybrid nanocomposite structure.

[0181] Furthermore, analysis of the FT patterns corresponding to different regions confirmed the obvious presence of layered and spinel structures.

[0182] This confirms the Co wet coating of Li[Ni] according to this embodiment. 0.9 Co 0.05 Mn 0.05The (OH)2 precursor has a layered and spinel nanocomposite crystal structure, which helps to improve electrochemical performance.

[0183] Referring to Figure 15, Co wet-coated Li[Ni] 0.9 Co 0.05 Mn 0.05 O2 and control cathode (Li[Ni) 0.98 Co 0.01 Mn 0.01 O2) in Diffraction peaks were observed at L(000) and L(012), confirming the layered structure. However, only in the Co wet-coated cathode did diffraction peaks appear. and Peaks were observed at the point, confirming the presence of layered and spinel structures, which are not present in the comparative example.

[0184] (Coating confirmation and electrochemical performance)

[0185] As shown in Figure 16, Co wet-coated Li[Ni] 0.9 Co 0.05 Mn 0.05 TEM-EDS analysis of the O2 cathode confirmed the presence of a Co coating primarily on the particle surface, ensuring enhanced electrochemical stability.

[0186] Furthermore, as shown in Table 7 and Figure 17, the presence of the spinel nanocomposite structure leads to a decrease in the I(003) / I(104) ratio, which indicates the degree of layered structure formation. This decrease, compared to the standard layered cathode, confirms the formation of both layered and spinel nanocomposite structures.

[0187] Table 7 presents the results of ICP-OES analysis on Co wet-coated Li[Ni] . 0.9 Co 0.05 Mn 0.05 O2 and conventional Li[Ni 0.9 Co 0.05 Mn 0.05 The chemical composition of O2 was determined, verifying the uniform incorporation of the Co coating and its expected stoichiometry.

[0188] [Table 7]

[0189]

[0190] [Table 8]

[0191]

[0192] [Table 9]

[0193]

[0194] Referring to Tables 8 and 9, it can be observed that Co wet-coated Li[Ni] 0.9 Co 0.05 Mn 0.05 O2 cathode materials show improvements in capacity, rate performance, and cycle life characteristics.

[0195] The formation of the layered and spinel nanocomposite crystal structure effectively disperses the strain forces that typically develop in the layered structure of nickel-rich cathodes during charge-discharge cycles. This strain relaxation significantly improves cycle life characteristics, indicating that the nanocomposite structure enhances the structural stability of the cathode material, thereby preventing rapid degradation and extending battery life.

[0196] These results confirm the effectiveness of Co wet-coated Li[Ni] 0.9 Co 0.05 Mn 0.05 O2 cathode materials offer superior electrochemical performance, making them promising candidates for high-performance lithium-ion batteries.

[0197] In addition, 3D Li + The formation of diffusion pathways (a key feature of spinel structures) significantly improved the performance of Co wet-coated Li[Ni] 0.9 Co 0.05 Mn 0.05 The rate performance of O2. This structural advantage helps to transport lithium ions more efficiently, enabling the cathode material to maintain a higher discharge capacity at high charge-discharge rates, thereby improving its overall electrochemical performance.

[0198] [Sb dry doping concentration gradient Li[Ni] 0.9 Co 0.05 Mn 0.05 [Description of O2-rich nickel-NCM cathode material]

[0199] Referring to Figures 18 and 19, the concentration gradient of Sb dry doping in Li[Ni] is described. 0.9 Co 0.05 Mn 0.05 Characteristics of O2 cathode materials. Figure 18: Showing the concentration gradient of Sb dry doping in Li[Ni]. 0.9 Co 0.05 Mn 0.05 TEM image of the crystal structure of O2. Figure 19: Concentration gradient of Sb dry doping in Li[Ni] 0.9 Co 0.05 Mn 0.05 O2 and conventional Li[Ni 0.9 Co0.05 Mn 0.05 Another TEM image of the crystal structure of O2.

[0200] (Structural characteristics)

[0201] Examination of the TEM images in Figure 18 reveals that the SAED pattern confirms the coexistence of layered and spinel structures. Furthermore, HR-TEM analysis reveals that these structures are interwoven, forming a layered and spinel nanocomposite structure. FT patterns corresponding to different regions confirm the presence of distinct layered and spinel phases.

[0202] This indicates that the concentration gradient of Sb dry doping according to this embodiment [Ni 0.9 Co 0.05 Mn 0.05 The (OH)2 precursor has a layered and spinel nanocomposite crystal structure, which helps to improve electrochemical performance.

[0203] Referring to Figure 19, the concentration gradient of Sb dry doping in Li[Ni] 0.9 Co 0.05 Mn 0.05 O2 and control cathode (Li[Ni) 0.98 Co 0.01 Mn 0.01 O2) in Diffraction peaks were observed at L(000) and L(012), confirming the layered structure. However, only in the Sb dry-doped cathode did diffraction peaks appear. and Peaks were observed at the point, confirming the presence of layered and spinel structures, which are not present in the comparative example.

[0204] Table 10 presents the concentration gradient of Sb dry doping in Li[Ni] as analyzed by ICP-OES. 0.9 Co 0.05 Mn 0.05 O2 and conventional concentration gradient Li[Ni 0.9 Co 0.05 Mn 0.05 Chemical composition of O2.

[0205] Table 11 evaluates the electrochemical performance (capacity and cycle life characteristics), showing that the Sb dry-doped cathode material exhibits enhanced capacity retention and long-term stability. Table 12 evaluates the rate performance, showing that the Sb dry-doped concentration gradient cathode material maintains a high discharge capacity at increased charge-discharge rates, confirming the improved high-rate performance.

[0206] The results confirmed that Sb dry doping combined with a concentration gradient structure enhances structural stability and electrochemical performance, making Li[Ni] 0.9Co 0.05 Mn 0.05 O2 is a promising cathode material for next-generation lithium-ion batteries.

[0207] [Table 10]

[0208]

[0209] [Table 11]

[0210]

[0211] [Table 12]

[0212]

[0213] The formation of layered and spinel nanocomposite crystal structures effectively disperses the strain forces that typically develop in the layered structure of nickel-rich cathodes during charge-discharge cycles. This strain relaxation significantly enhances cycle life characteristics, prevents structural degradation, and extends battery life.

[0214] Furthermore, the presence of the spinel structure provides 3D Li + The diffusion pathway facilitates more efficient lithium-ion transport. This structural advantage leads to a significant improvement in rate performance, enabling the cathode material to maintain a high discharge capacity at high charge-discharge rates, thereby enhancing overall electrochemical performance.

[0215] Ti wet-doped and Mo dry-doped Li[Ni] 0.88 Co 0.06 Mn 0.06 [Description of O2-rich nickel-NCM cathode material]

[0216] Referring to Figures 20 to 22, the wet-doped Ti and dry-co-doped Li[Ni] are described. 0.88 Co 0.06 Mn 0.06 Characteristics of O2 cathode materials. Figures 20 and 21: showing Ti wet-doped and Mo dry-doped Li[Ni] 0.88 Co 0.06 Mn 0.06 TEM image of the crystal structure of O2. Figure 22: Li[Ni]2O2 crystals showing wet Ti doping and dry Mo co-doping. 0.88 Co 0.06 Mn 0.06 O2 and conventional Li[Ni 0.88 Co 0.06 Mn 0.06 XRD pattern of O2 crystal structure.

[0217] (Structural characteristics)

[0218] Examination of the TEM images in Figure 20 reveals that the SAED patterns confirm the coexistence of layered and spinel structures. Furthermore, HR-TEM analysis reveals that these structures are interwoven, forming a layered and spinel nanocomposite structure. FT patterns corresponding to different regions confirm the presence of distinct layered and spinel phases.

[0219] This indicates that, according to this embodiment, Ti wet doping and Mo dry co-doping of Li[Ni] 0.88 Co 0.06 Mn 0.06 O2 has a layered and spinel nanocomposite crystal structure, which helps to improve electrochemical performance.

[0220] Referring to Figure 21, Li[Ni] co-doped with Ti wet doping and Mo dry doping 0.88 Co 0.06 Mn 0.06 O2 and control cathode (Li[Ni) 0.88 Co 0.06 Mn 0.06 O2) in Diffraction peaks were observed at L(000) and L(012), confirming the layered structure. However, this layered structure was only observed in the Ti wet-doped and Mo dry-doped cathodes. and Peaks were observed at the point, confirming the presence of layered and spinel structures, which are not present in the comparative example.

[0221] Referring to Table 13 and Figure 22, the I(003) / I(104) ratio, representing the degree of layered structure formation, decreased from 2.12 in the standard cathode to 1.80 in the Ti wet-doped and Mo dry-doped co-doped cathode. This reduction confirms the formation of layered and spinel nanocomposite structures, which play a crucial role in improving the structural stability and electrochemical performance of the cathode material.

[0222] Table 13 presents the Ti wet-doped and Mo dry-co-doped Li[Ni] slurries analyzed using ICP-OES. 0.88 Co 0.06 Mn 0.06 The chemical composition of O2 was determined to verify the uniform incorporation of the dopant and its effect on the material properties. Tables 14 and 15 present the results of Ti wet doping and Mo dry co-doping of Li[Ni] . 0.88 Co 0.06 Mn 0.06 The electrochemical performance of O2, including capacity, cycle life characteristics and rate performance.

[0223] [Table 13]

[0224]

[0225] [Table 14]

[0226]

[0227] [Table 15]

[0228]

[0229] As described above, the formation of the layered and spinel nanocomposite crystal structure effectively disperses the strain forces that typically develop in the layered structure of nickel-rich cathodes during charge-discharge cycles. This strain relaxation significantly enhances cycle life characteristics, prevents structural degradation, and extends battery life.

[0230] Furthermore, the presence of the spinel structure provides 3D Li + The diffusion pathway facilitates more efficient lithium-ion transport. This structural advantage leads to a significant improvement in rate performance, enabling the cathode material to maintain a high discharge capacity at high charge-discharge rates, thereby enhancing overall electrochemical performance.

[0231] The following sections describe the evaluation results of nickel-rich NCA cathode materials with the following compositions, tested at 2.7–4.3 V and 30 °C.

[0232] Nickel-rich NCA cathode material

[0233] Ta and Al dry co-doped Li[Ni] 0.89 Co 0.1 Al 0.01 O2

[0234] W and Al co-doped Li[Ni] 0.87 Co 0.10 Al 0.03 O2

[0235] Ta, Al dry co-doped Li[Ni] 0.89 Co 0.1 Al 0.01 [Description of O2-rich nickel-NCA cathode material]

[0236] Referring to Figures 23 and 24, dry co-doping of Li[Ni] with Ta and Al is described. 0.89 Co 0.1 Al 0.01 Characteristics of O2 cathode materials. Figures 23 and 24: Ta and Al dry co-doped Li[Ni] 0.89Co 0.1 Al 0.01 O2 and conventional Li[Ni 0.89 Co 0.1 Al 0.01 TEM image of the crystal structure of O2.

[0237] (Structural characteristics)

[0238] Examination of the TEM images in Figure 23 reveals that the SAED pattern confirms the coexistence of layered and spinel structures. Furthermore, HR-TEM analysis reveals that these structures are interwoven, forming a layered and spinel nanocomposite structure. FT patterns corresponding to different regions confirm the presence of different layered and spinel phases.

[0239] This indicates that, according to this implementation scheme, Ta and Al dry co-doped Li[Ni] 0.89 Co 0.1 Al 0.01 O2 has a layered and spinel nanocomposite crystal structure, which helps to improve electrochemical performance.

[0240] Referring to Figure 24, Ta and Al dry co-doped Li[Ni] 0.89 Co 0.1 Al 0.01 O2 and control cathode (Li[Ni) 0.89 Co 0.1 Al 0.01 O2) in Diffraction peaks were observed at L(000) and L(012), confirming the layered structure. However, this was only observed in the Ta and Al dry-doped cathode. and Peaks were observed at the point, confirming the presence of layered and spinel structures, which are not present in the comparative example.

[0241] Table 16 below presents Ta and Al dry co-doped Li[Ni] 0.89 Co 0.1 Al 0.01 O2 and conventional Li[Ni 0.89 Co 0.1 Al 0.01 Chemical composition of O2 (ICP-OES analysis).

[0242] In addition, Tables 17 and 18 show Ta and Al dry-doped Li[Ni] 0.89 Co 0.1 Al 0.01 O2 and conventional Li[Ni 0.89 Co 0.1 Al 0.01Electrochemical performance of O2 (capacity, cycle life characteristics and rate performance).

[0243] The results confirmed that dry co-doping with Ta and Al enhanced structural stability and electrochemical performance, making Li[Ni] 0.89 Co 0.1 Al 0.01 O2 is a promising cathode material for next-generation lithium-ion batteries.

[0244] [Table 16]

[0245]

[0246] [Table 17]

[0247]

[0248] [Table 18]

[0249]

[0250] The formation of layered and spinel nanocomposite crystal structures effectively disperses the strain forces that typically develop in the layered structure of nickel-rich cathodes during charge-discharge cycles. This strain relaxation significantly enhances cycle life characteristics, prevents structural degradation, and extends battery life.

[0251] Furthermore, the presence of the spinel structure provides 3D Li + The diffusion pathway facilitates more efficient lithium-ion transport. This structural advantage leads to a significant improvement in rate performance, enabling the cathode material to maintain a high discharge capacity at high charge-discharge rates, thereby enhancing overall electrochemical performance.

[0252] [W, Al two-step co-doped Li[Ni] 0.87 Co 0.10 Al 0.03 [Description of O2-rich nickel-NCA cathode material]

[0253] Referring to Figures 25 and 26, a two-step co-doping of Li[Ni] with W and Al is described. 0.87 Co 0.10 Al 0.03 Characteristics of O2 cathode materials. Figures 25 and 26: showing the characteristics of Li[Ni] co-doped with W and Al in two steps. 0.87 Co 0.10 Al 0.03 O2 and conventional Li[Ni 0.87 Co 0.10 Al 0.03 TEM image of the crystal structure of O2.

[0254] (Structural characteristics)

[0255] Examination of the TEM images in Figure 25 reveals that the SAED patterns confirm the coexistence of layered and spinel structures. Furthermore, HR-TEM analysis reveals that these structures are interwoven, forming a layered and spinel nanocomposite structure. FT patterns corresponding to different regions confirm the presence of different layered and spinel phases.

[0256] This indicates that, according to this implementation scheme, Li[Ni] is co-doped in two steps using W and Al. 0.87 Co 0.10 Al 0.03 O2 has a layered and spinel nanocomposite crystal structure, which helps to improve electrochemical performance.

[0257] Referring to Figure 26, W and Al co-doped Li[Ni] 0.87 Co 0.10 Al 0.03 O2 and control cathode (Li[Ni) 0.87 Co 0.10 Al 0.03 O2, Comparative Example 3) Diffraction peaks were observed at L(000) and L(012), confirming the layered structure. However, this layered structure was only observed in the W and Al two-step dry co-doped cathode. and Peaks were observed at the point, confirming the presence of layered and spinel structures, which are not present in the comparative example.

[0258] Table 19 presents the W and Al two-step co-doped Li[Ni] slurry analysis using ICP-OES. 0.87 Co 0.10 Al 0.03 O2 and conventional Li[Ni 0.87 Co 0.10 Al 0.03 The chemical composition of O2 is shown in Table 20. Table 20 evaluates the electrochemical performance (capacity and cycle life characteristics), indicating that the W and Al co-doped cathode material exhibits enhanced capacity retention and long-term stability. Table 21 evaluates the rate performance, showing that the co-doped cathode material maintains a high discharge capacity at increased charge / discharge rates, confirming its superior high-rate performance.

[0259] The results confirmed that the two-step co-doping of W and Al enhanced the structural stability and electrochemical performance of Li[Ni]. 0.87 Co 0.10 Al 0.03 O2 is a promising cathode material for next-generation lithium-ion batteries.

[0260] [Table 19]

[0261]

[0262] [Table 20]

[0263]

[0264] [Table 21]

[0265]

[0266] As described above, the formation of the layered and spinel nanocomposite crystal structure effectively disperses the strain forces that typically develop in the layered structure of nickel-rich cathodes during charge-discharge cycles. This strain relaxation significantly enhances cycle life characteristics, prevents structural degradation, and extends battery life.

[0267] Furthermore, the presence of the spinel structure provides 3D Li + The diffusion pathway facilitates more efficient lithium-ion transport. This structural advantage leads to a significant improvement in rate performance, enabling the cathode material to maintain a high discharge capacity at high charge-discharge rates, thereby enhancing overall electrochemical performance.

[0268] The following section describes the evaluation results of nickel-rich NM cathode materials with the following compositions, tested at 2.7–4.3 V and 30 °C.

[0269] Nickel-rich NM cathode material

[0270] Li[Ni] (wet doping with W and dry co-doping with Ti) 0.91 Mn 0.09 O2

[0271] [W wet doping and Ti dry co-doping of Li[Ni] 0.91 Mn 0.09 [Description of O2-rich nickel-NM cathode material]

[0272] Referring to Figures 27 and 28, W wet doping and Ti dry co-doping of Li[Ni] are described. 0.91 Mn 0.09 Characteristics of O2 cathode materials. Figures 27 and 28: showing W wet doping and Ti dry co-doping of Li[Ni] 0.91 Mn 0.09 O2 and conventional Li[Ni 0.91 Mn 0.09 TEM image of the crystal structure of O2.

[0273] {Structural Characteristics}

[0274] Examination of the TEM images in Figure 27 reveals that the SAED pattern confirms the coexistence of layered and spinel structures. Furthermore, HR-TEM analysis reveals that these structures are interwoven, forming a layered and spinel nanocomposite structure. FT patterns corresponding to different regions confirm the presence of different layered and spinel phases.

[0275] This indicates that, according to this embodiment, W wet doping and Ti dry co-doping of Li[Ni] 0.91 Mn 0.09 O2 has a layered and spinel nanocomposite crystal structure, which helps to improve electrochemical performance.

[0276] Referring to Figure 28, Li[Ni] co-doped by wet W and dry Ti is shown. 0.91 Mn 0.09 O2 and control cathode (Li[Ni) 0.91 Mn 0.09 O2, Comparative Example 4) Diffraction peaks were observed at L(000) and L(012), confirming the layered structure. However, diffraction peaks were only observed in the W and Ti co-doped cathode. and Peaks were observed at the point, confirming the presence of layered and spinel structures, which are not present in the comparative example.

[0277] Table 22 presents the W wet-doped and Ti dry-doped Li[Ni] slurries analyzed using ICP-OES. 0.91 Mn 0.09 O2 and conventional Li[Ni 0.91 Mn 0.09 The chemical composition of O2 is shown in Table 23. Table 23 evaluates the electrochemical performance (capacity and cycle life characteristics), indicating that the W and Ti co-doped cathode material exhibits enhanced capacity retention and long-term stability. Table 24 evaluates the rate performance, showing that the co-doped cathode material maintains a high discharge capacity at increased charge / discharge rates, confirming its superior high-rate performance.

[0278] The results confirmed that wet doping with W and dry co-doping with Ti simultaneously improved structural stability and electrochemical performance, making Li[Ni 0.91 Mn 0.09 O2 is a promising cathode material for next-generation lithium-ion batteries.

[0279] [Table 22]

[0280]

[0281] [Table 23]

[0282]

[0283] [Table 24]

[0284]

[0285] As described above, the formation of the layered and spinel nanocomposite crystal structure effectively disperses the strain forces that typically develop in the layered structure of nickel-rich cathodes during charge-discharge cycles. This strain relaxation significantly enhances cycle life characteristics, prevents structural degradation, and extends battery life.

[0286] Furthermore, the presence of the spinel structure provides 3D Li + The diffusion pathway facilitates more efficient lithium-ion transport. This structural advantage leads to a significant improvement in rate performance, enabling the cathode material to maintain a high discharge capacity at high charge-discharge rates, thereby enhancing overall electrochemical performance.

[0287] The following sections describe the evaluation results of mid-Ni cathode materials with the following compositions, tested at 2.7–4.5 V and 45 °C. These materials are specifically designed to exhibit excellent high-voltage and high-temperature performance.

[0288] Medium-nickel cathode materials

[0289] Co wet-coated, W dry-doped Li[Ni] 0.7 Co 0.1 Mn 0.2 O2

[0290] Concentration gradient of W and Zr dry co-doping Li[Ni 0.7 Co 0.05 Mn 0.25 O2

[0291] Mo-doped Li[Ni] 0.6 Mn 0.4 O2

[0292] Co wet-coated, W dry-doped Li[Ni] 0.7 Co 0.1 Mn 0.2 [Description of O2]

[0293] Referring to Figures 29 to 31, Co wet-coated, W dry-doped Li[Ni] is described. 0.7 Co 0.1 Mn 0.2 Characteristics of O2 cathode materials. Figure 29: Co wet-coated [Ni 0.7 Co 0.1 Mn 0.2SEM images of the (OH)₂ precursor. Figures 30 and 31 show Co wet-coated, W dry-doped Li[Ni]₂. 0.7 Co 0.1 Mn 0.2 O2 and conventional Li[Ni 0.7 Co 0.1 Mn 0.2 TEM image of the crystal structure of O2.

[0294] (Structural characteristics)

[0295] Examining the SEM image in Figure 29, the Co wet-coated W dry-doped [Ni] 0.7 Co 0.1 Mn 0.2 The (OH)2 precursor is spherical with a particle size of about 10 μm in diameter.

[0296] In Figure 30, the SAED pattern confirms the coexistence of layered and spinel structures. Furthermore, HR-TEM analysis reveals that these structures are interwoven, forming a layered and spinel nanocomposite structure. FT patterns corresponding to different regions confirm the presence of different layered and spinel phases.

[0297] This indicates that the Co wet-coated, W dry-doped Li[Ni] according to this embodiment... 0.7 Co 0.1 Mn 0.2 O2 has a layered and spinel nanocomposite crystal structure, which helps to improve electrochemical performance.

[0298] Referring to Figure 31, Co wet-coated, W dry-doped Li[Ni] 0.7 Co 0.1 Mn 0.2 O2 and control cathode (Li[Ni) 0.7 Co 0.1 Mn 0.2 O2, Comparative Example 5) Diffraction peaks were observed at L(000) and L(012), confirming the layered structure. However, only in the Co- and W co-doped cathode did diffraction peaks appear. and Peaks were observed at the point, confirming the presence of layered and spinel structures, which are not present in the comparative example.

[0299] Table 25 presents the results of ICP-OES analysis of Co wet-coated and W dry-doped Li[Ni] silanes. 0.7 Co 0.1 Mn 0.2 O2 and conventional Li[Ni 0.7 Co 0.1 Mn0.2 The chemical composition of O2 is shown in Table 26. Table 26 evaluates the electrochemical performance (capacity and cycle life characteristics), indicating that the Co / W co-doped cathode material exhibits enhanced capacity retention and long-term stability. Table 27 evaluates the rate performance, showing that the co-doped cathode material maintains a high discharge capacity at increased charge / discharge rates, confirming its superior high-rate performance.

[0300] The results confirmed that wet Co coating and dry W doping enhanced the structural stability and electrochemical performance of Li[Ni]. 0.7 Co 0.1 Mn 0.2 O2 is a promising cathode material for next-generation lithium-ion batteries.

[0301] [Table 25]

[0302]

[0303] [Table 26]

[0304]

[0305] [Table 27]

[0306]

[0307] As described above, the formation of the layered and spinel nanocomposite crystal structure effectively disperses the strain forces that typically develop in the layered structure of nickel-rich cathodes during charge-discharge cycles. This strain relaxation significantly enhances cycle life characteristics, prevents structural degradation, and extends battery life.

[0308] Furthermore, the presence of the spinel structure provides 3D Li + The diffusion pathway facilitates more efficient lithium-ion transport. This structural advantage leads to a significant improvement in rate performance, enabling the cathode material to maintain a high discharge capacity at high charge-discharge rates, thereby enhancing overall electrochemical performance.

[0309] [W, Zr dry co-doping concentration gradient Li[Ni] 0.7 Co 0.05 Mn 0.25 [Description of nickel cathode material in O2]

[0310] Referring to Figures 32 and 33, the concentration gradient of W and Zr dry co-doping in Li[Ni] is described. 0.7 Co 0.05 Mn 0.25 Characteristics of O2 cathode materials. Figures 32 and 33 show the concentration gradient of W and Zr dry co-doping in Li[Ni].0.7 Co 0.05 Mn 0.25 O2 and the conventional concentration gradient Li[Ni 0.7 Co 0.05 Mn 0.25 TEM image of the crystal structure of O2.

[0311] (Structural characteristics)

[0312] Examination of the TEM images in Figure 32 reveals that the SAED pattern confirms the coexistence of layered and spinel structures. Furthermore, HR-TEM analysis reveals that these structures are interwoven, forming a layered and spinel nanocomposite structure. FT patterns corresponding to different regions confirm the presence of different layered and spinel phases.

[0313] This indicates that, according to this implementation scheme, the concentration gradient of W and Zr dry co-doping in Li[Ni] 0.7 Co 0.05 Mn 0.25 O2 has a layered and spinel nanocomposite crystal structure, which helps to improve electrochemical performance.

[0314] Referring to Figure 33, the concentration gradient of W and Zr dry co-doping in Li[Ni] 0.7 Co 0.05 Mn 0.25 O2 and control cathode (Li[Ni) 0.7 Co 0.05 Mn 0.25 O2, Comparative Example 6) Diffraction peaks were observed at L(000) and L(012), confirming the layered structure. However, diffraction peaks were only observed in the W and Zr co-doped cathode. and Peaks were observed at the point, confirming the presence of layered and spinel structures, which are not present in the comparative example.

[0315] Table 28 presents the concentration gradient of W and Zr dry co-doping Li[Ni] as analyzed by ICP-OES. 0.7 Co 0.05 Mn 0.25 O2 and the conventional concentration gradient Li[Ni 0.7 Co 0.05 Mn 0.25 The chemical composition of O2 is shown in Table 29. Table 29 evaluates the electrochemical performance (capacity and cycle life characteristics), indicating that the W and Zr co-doped cathode material exhibits enhanced capacity retention and long-term stability. Table 30 evaluates the rate performance, showing that the co-doped cathode material maintains a high discharge capacity at increased charge / discharge rates, confirming its superior high-rate performance.

[0316] The results confirmed that dry co-doping with W and Zr enhanced structural stability and electrochemical performance, making Li[Ni] 0.7 Co 0.05 Mn 0.25 O2 is a promising cathode material for next-generation lithium-ion batteries.

[0317] [Table 28]

[0318]

[0319] [Table 29]

[0320]

[0321] [Table 30]

[0322]

[0323] As described above, the formation of the layered and spinel nanocomposite crystal structure effectively disperses the strain forces that typically develop in the layered structure of nickel-rich cathodes during charge-discharge cycles. This strain relaxation significantly enhances cycle life characteristics, prevents structural degradation, and extends battery life.

[0324] Furthermore, the presence of the spinel structure provides 3D Li + The diffusion pathway facilitates more efficient lithium-ion transport. This structural advantage leads to a significant improvement in rate performance, enabling the cathode material to maintain a high discharge capacity at high charge-discharge rates, thereby enhancing overall electrochemical performance.

[0325] Mo-doped Li[Ni] 0.6 Mn 0.4 [Description of nickel cathode material in O2]

[0326] Referring to Figures 34 to 36, the two-step Mo-doped Li[Ni] is described. 0.6 Mn 0.4 Characteristics of O2 cathode materials. Figures 34 and 35: showing the two-step Mo-doped Li[Ni] 0.6 Mn 0.4 O2 and conventional Li[Ni 0.6 Mn 0.4 TEM image of the crystal structure of O2. Figure 36: Li[Ni]2-doped with Mo in two steps. 0.6 Mn 0.4 O2 and conventional Li[Ni 0.6 Mn 0.4 XRD pattern of O2 crystal structure.

[0327] (Structural characteristics)

[0328] Examination of the TEM images in Figure 34 reveals that the SAED pattern confirms the coexistence of layered and spinel structures. Furthermore, HR-TEM analysis reveals that these structures are interwoven, forming a layered and spinel nanocomposite structure. FT patterns corresponding to different regions confirm the presence of different layered and spinel phases.

[0329] This indicates that, according to this implementation scheme, Mo-doped Li[Ni]2-step doping 0.6 Mn 0.4 O2 has a layered and spinel nanocomposite crystal structure, which helps to improve electrochemical performance.

[0330] Referring to Figure 35, Mo-doped Li[Ni]2-step process 0.6 Mn 0.4 O2 and control cathode (Li[Ni) 0.6 Mn 0.4 O2, Comparative Example 7) Diffraction peaks were observed at L(000) and L(012), confirming the layered structure. However, only in the Mo two-step doped cathode did diffraction peaks appear. and Peaks were observed at the point, confirming the presence of layered and spinel structures, which are not present in the comparative example.

[0331] Referring to Figure 36, the ratio of I(003) / I(104), representing the degree of layered structure development, decreases from 2.07 in the standard cathode to 1.97 in the Mo two-step doped cathode. This reduction confirms the formation of a layered and spinel nanocomposite structure, which plays a crucial role in improving the structural stability and electrochemical performance of the cathode material.

[0332] Table 31 presents the results of two-step Mo-doped Li[Ni]2 using ICP-OES analysis. 0.6 Mn 0.4 O2 and conventional Li[Ni 0.6 Mn 0.4 Chemical composition of O2. Tables 32 and 33 present the concentration gradient of Mo two-step doping Li[Ni]. 0.6 Mn 0.4 O2 and conventional Li[Ni 0.6 Mn 0.4 Electrochemical performance of O2 (capacity, cycle life characteristics and rate performance).

[0333] The results confirmed that the two-step Mo doping enhanced the structural stability and electrochemical performance of Li[Ni]. 0.6 Mn 0.4 O2 is a promising cathode material for next-generation lithium-ion batteries.

[0334] [Table 31]

[0335]

[0336] [Table 32]

[0337]

[0338] [Table 33]

[0339]

[0340] As described above, the formation of the layered and spinel nanocomposite crystal structure effectively disperses the strain forces that typically develop in the layered structure of nickel-rich cathodes during charge-discharge cycles. This strain relaxation significantly enhances cycle life characteristics, prevents structural degradation, and extends battery life.

[0341] Furthermore, the presence of the spinel structure provides 3D Li + The diffusion pathway facilitates more efficient lithium-ion transport. This structural advantage leads to a significant improvement in rate performance, enabling the cathode material to maintain a high discharge capacity at high charge-discharge rates, thereby enhancing overall electrochemical performance.

[0342] Therefore, this invention introduces a nanocomposite structure integrating spinel and layered structures, providing various performance enhancements compared to conventional layered cathode materials. Conventional layered cathode materials exhibit increased structural instability during repeated charge-discharge cycles, leading to structural breakdown during long-term use. In contrast, the nanocomposite structure introduced in this invention provides 3D Li + The diffusion pathway significantly enhances structural stability and mitigates degradation. While conventional cathode materials offer high capacity, they suffer from poor lithium-ion diffusion, resulting in low rate performance. The introduction of the spinel structure improves lithium-ion transport, enabling faster charge-discharge cycles and higher rate performance.

[0343] In layered cathodes, the accumulation of mechanical strain during charge-discharge cycles leads to a decline in long-term cycle performance. The nanocomposite structure of this invention effectively disperses mechanical stress, increasing battery life by 10%-20% compared to conventional materials. Improved thermal and voltage stability: Nickel-rich cathodes are prone to oxygen release and thermal instability at high voltages (above 4.2V), posing safety risks. The nanocomposite cathode developed in this invention improves thermal stability, enabling the battery to operate safely and effectively at voltages above 4.5V.

[0344] The spinel-layered nanocomposite cathode material developed in this invention successfully overcomes the limitations of conventional single-structure cathodes and provides a significant improvement in the performance of lithium-ion batteries.

[0345] This invention improves electrochemical performance and cycle life by integrating layered and spinel structures at the nanoscale, while maintaining compatibility with existing manufacturing processes. The proposed high-performance cathode material and cost-effective production method have enormous industrial application potential, driving the development of next-generation high-energy, long-life lithium-ion batteries.

[0346] The above exemplary embodiments are only used to describe exemplary embodiments of the present invention and are not limited to these exemplary embodiments.

Claims

1. A positive electrode active material for lithium secondary batteries, comprising secondary particles composed of multiple primary particles, wherein, The primary particles comprise a nanocomposite structure, in which spinel (Fd3m) structure and layered structure are present. The structure is a nanoscale hybrid.

2. The positive electrode active material for lithium secondary batteries according to claim 1, wherein, SAED electron diffraction images show S(a,a,a+2) and S(b,b,b-2) electron diffraction spots.

3. The positive electrode active material for lithium secondary batteries according to claim 2, wherein, In the SAED electron diffraction pattern, the peak intensity of the L(0, -1, -2-3(m-1)) plane is greater than that of the S(a, a, a+2) plane, and the peak intensity of the L(0, 1, 2+3(n-1)) plane is greater than that of the S(b, b, b-2) plane.

4. The positive electrode active material for lithium secondary batteries according to claim 1, wherein, The maximum length passing through the center of the cross-section of the spinel-forming region is 1 nm to 100 nm, and the cross-sectional area of ​​the spinel-forming region is 1 nm. 2 Up to 10000nm 2 .

5. The positive electrode active material for lithium secondary batteries according to claim 1, wherein, The nanocomposite material is located inside or on the surface of the primary particles, and inside or on the surface of the secondary particles.

6. The positive electrode active material for lithium secondary batteries according to claim 1, wherein, The nanocomposite material was observable before the start of the charge-discharge cycle.

7. The positive electrode active material for lithium secondary batteries according to claim 1, wherein, The nanocomposite material provides a three-dimensional (3D) Li+ transport path in the charged state, thereby improving the rate performance of the cathode material.

8. The positive electrode active material for lithium secondary batteries according to claim 1, wherein, The nanocomposite material that could be observed before the charge-discharge cycle can still be found after the cycle, and the nanocomposite material found inside the primary particles after the cycle can be distinguished from the spinel impurities formed on the surface of the secondary particles due to electrode degradation.

9. The positive electrode active material for lithium secondary batteries according to claim 1, wherein, The primary particles contain nickel (Ni), M1 and M2, where M1 includes at least one of cobalt (Co), manganese (Mn) and aluminum (Al), nickel (Ni) is present in ≥50 mol%, and M2 is a dopant element present in 0.05 mol% to 10 mol%.

10. The positive electrode active material for lithium secondary batteries according to claim 9, wherein, M2 includes at least one selected from cobalt (Co), manganese (Mn), titanium (Ti), magnesium (Mg), tantalum (Ta), niobium (Nb), tungsten (W), molybdenum (Mo), antimony (Sb), tellurium (Te), tin (Sn), ruthenium (Ru), boron (B), hafnium (Hf), gallium (Ga), germanium (Ge), chromium (Cr), vanadium (V), copper (Cu), calcium (Ca), zinc (Zn), barium (Ba), strontium (Sr), aluminum (Al), and zirconium (Zr).

11. The positive electrode active material for lithium secondary batteries according to claim 10, wherein, The positive electrode active material is obtained by mixing a composite metal hydroxide precursor (A(OH)2) with M2 and subjecting it to high-temperature heat treatment, wherein A is at least one selected from Ni, Co, Mn or Al.

12. The positive electrode active material for lithium secondary batteries according to claim 10, wherein, The positive electrode active material is obtained by mixing an M2-doped composite metal hydroxide precursor with a lithium precursor and then subjecting it to high-temperature heat treatment, wherein A is selected from Ni, Co, Mn or Al.

13. The positive electrode active material for lithium secondary batteries according to claim 10, wherein, The positive electrode active material is obtained by mixing an M2-coated composite metal hydroxide precursor with a lithium precursor and subjecting it to high-temperature heat treatment, wherein A is selected from Ni, Co, Mn or Al.

14. The positive electrode active material for lithium secondary batteries according to claim 10, wherein, The positive electrode active material is obtained by mixing M2-doped A(OH)2 precursor or M2-coated A(OH)2 precursor with lithium precursor and another M2, followed by high-temperature heat treatment, wherein A is selected from Ni, Co, Mn or Al.

15. The positive electrode active material for lithium secondary batteries according to claim 10, wherein, A concentration gradient of Ni, Co, or Mn is formed within the primary particles.

16. The positive electrode active material for lithium secondary batteries according to claim 10, wherein, The positive electrode active material for lithium secondary batteries is obtained through the following steps: a first calcination step in which at least one of a composite metal hydroxide A(OH)2 precursor and a wet-doped composite metal hydroxide A(OH)2 precursor is mixed with a lithium source; a subsequent second calcination step in which a dry dopant is introduced and further high-temperature heat treatment is performed.

Images