Positive electrode active material and method for manufacturing the same, positive electrode sheet, battery and power consumption equipment

Abstract

The present invention relates to a lithium ion battery, particularly to a positive electrode active material, a method for producing the same, a positive electrode sheet, a battery, and an electric power consumption device. The deviation angle of the diffraction peak (104) of the positive electrode active material is α n m where n is the number of charge cycles of the battery including the positive electrode active material and is an integer, and m% is the percentage of the charge capacity at the n-th charge of the battery to the total capacity of the battery. α n m is the 2θ value corresponding to the diffraction peak (104) in the XRD diffraction pattern of the anode active material when the percentage of the charge capacity at the n-th charge of the battery to the total capacity of the battery is m%, and α 100 50 -α 100 satisfies 0 ≦ 0.250° and α 100 100 -α 100 satisfies 0 ≦ 1.500°.

Description

[Technical Field]

[0001] This application claims priority based on a patent application filed in China on April 30, 2024 (application number 202410545370.7), and the entire disclosure of that earlier application is incorporated herein by reference.

[0002] The present invention relates to the technical field of lithium-ion batteries, and more particularly to positive electrode active materials and methods for manufacturing the same, positive electrode sheets, batteries, and power consumption equipment. [Background technology]

[0003] Currently, lithium-ion batteries are among the most advanced rechargeable batteries to date. Since Sony introduced the technology to the market in 1991, lithium-ion batteries have been widely used in fields such as mobile phones, laptops, and new energy vehicles. Electrode materials, as the core element of batteries, continue to drive the development and progress of lithium-ion batteries in research and development. Compared to anode materials, cathode materials are the most important factor influencing battery performance, directly determining the capacity and recyclability of lithium-ion batteries. Therefore, to further improve the safety performance and specific energy of batteries, it is necessary to develop superior cathode materials that meet these requirements.

[0004] The continuous optimization and innovation of ternary materials is a crucial element in the development of cathode materials for lithium-ion batteries and is of significant importance in improving the driving range of new energy vehicles. The structural formula of the ternary material is LiNi x Co y M 1-x-yO2 (where M is Mn or Al) is divided into NCM and NCA depending on the difference in the metallic element M. The ternary material NCM combines the advantages of cobalt and manganese doping, compensating to some extent for the shortcomings of each, and has advantages such as high specific capacity, good magnification performance, low cost, and low environmental pollution, making it one of the mainstream choices for battery cathode materials today and being widely developed and used. Specifically, the ternary material NCM has the crystal structure of α-NaFeO2 and the R3m space group. By changing the composition ratio of Ni, Co, and Mn, it is possible to adjust many properties such as capacity and safety performance to some extent, and the material is usually named according to the ratio of the materials, for example, 111 / 442 / 622 (representing the proportions of Ni, Mn, and Co, respectively). With market demand and the advancement of research, the composition ratio of Ni is increasingly shifting towards a high proportion of Ni and a low proportion of Co and Mn, and ternary materials with a Ni proportion of 80% and even over 90% are gradually becoming the mainstream in the market. Increasing the proportion of Ni leads to higher energy density, but also results in problems such as deterioration of circulation performance and reduced safety due to the instability of the material structure after charge-discharge cycles. As the Ni content increases, the instability problems present in this crystal structure also spread, and the phenomenon of mixing Li / Ni lattice positions is frequently observed in high-nickel ternary materials. This is because Ni 2+ The ionic radius (0.069 nm) of Li + Because the ionic radius is close to (0.076 nm) and the transfer energy barrier of nickel ions is very low, Ni 2+ Li + This is due to the ease with which Li / Ni can move to different lattice positions. This phenomenon is present both during the synthesis stage of the ternary material and during the charge-discharge process. If the phenomenon of mixing Li / Ni into the lattice positions deteriorates, it affects lithium ion de-implantation and electrochemical properties. This structural defect increases the internal resistance of the material, lowers electrochemical activity, and worsens circulation performance. However, if the Li / Ni lattice positions are mixed appropriately, the Ni atoms mixed into the Li layer can interact with the O atoms, helping to stabilize the material structure. In addition, during the repeated charge-discharge process of the material, the original layered structure is affected by Li +As the charge-discharge cycle repeats, the Li layer changes in response to the interaction between the transition metal ions and the oxygen layer, and the valence state of the transition metal changes. The Li layer cannot return to its original state before and after charging and discharging, and this irreversibly changes the relative position of the transition metal layer and the oxygen layer. As the number of charge-discharge cycles increases, this change gradually deepens, severely affecting the stability of the transition metal layer and the lifespan of the material itself. This material structure is intuitively reflected in the XRD properties as the charge-discharge cycle changes. The

[0104] peak, which represents the hexagonal and cubic structures, shifts to the right as lithium escapes, but when lithium returns to the lithium layer, the

[0104] peak may move back to its initial position. However, due to structural changes caused by the mixing of Li / Ni into the lattice positions, it cannot return to its original position.

[0005] To solve the above problems, current technical means include controlling the structural morphology of granule size by adjusting the sintering curve, as well as coating, doping, and single crystallization. Current research and inventions typically utilize doping to enhance the strength of the granules themselves, restrict direct contact between the electrolyte and the cathode material through coating, or directly achieve the above objectives through single crystallization. However, as market factors accelerate the rapid development of high-nickel materials, the phenomenon of mixing Li / Ni lattice positions within the material itself, as well as the phenomenon of mixing large amounts of Li / Ni into the lattice positions during the recycling process, have become significant factors constraining the development of high-nickel ternary materials. Conventional improvement methods are insufficient to improve the performance of high-nickel ternary materials. Therefore, further optimization of the synthesis process of the material itself is of unprecedented importance. [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] This invention aims to solve, at least to some extent, one of the technical problems of related technologies. Therefore, one of the objectives of this invention is to propose a positive electrode active material and a method for manufacturing the same in order to solve the problem that the structure of the positive electrode material is unstable during the charging and discharging process of a battery, resulting in a short cyclic life. [Means for solving the problem]

[0007] In the first aspect of the present invention, a positive electrode active material is proposed. The offset angle of the diffraction peak of (104) of the positive electrode active material is α n m is as follows.

[0008] n is the number of charge cycles of the battery including the positive electrode active material and is an integer.

[0009] m% is the percentage of the charge capacity when the battery is charged for the nth time to the total capacity of the battery.

[0010] α n m is the 2θ value corresponding to the diffraction peak of (104) in the XRD diffraction pattern of the anode active material when the percentage of the charge capacity when the battery is charged for the nth time to the total capacity of the battery is m%.

[0011] α n m is α 100 50 -α 100 is such that 0≦0.250° and α 100 100 100 -α 100 0≦1.500° is satisfied.

[0012] The present invention uses the offset angle α of the (104) diffraction peak n m to intuitively reflect the reversibility of the structure of the positive electrode active material during the insertion and extraction of Li + and the structural stability of the positive electrode active material in the extraction state of Li + When α of the positive electrode active material satisfies the above conditions, the positive electrode active material can maintain stability during multiple charge-discharge processes, and the cycle life of the battery including the same is prolonged. n m is satisfied.

[0013] Based on the embodiments of the present invention, the height change value ΔS of the transition metal layer of the positive electrode active material ( T MO2) is such that ΔS ( T MO2) <0.50 Å is satisfied. ΔS ( T MO2) =S ( T MO2) 0 -S ( T MO2) 1

[0014] ΔS ( T MO2) This is the change in altitude of the transition metal layer in the positive electrode active material of the battery containing the positive electrode active material when it is first fully charged and before charging.

[0015] S ( T MO2) 1 This is the altitude value of the transition metal layer in the positive electrode active material when the battery containing the positive electrode active material is fully charged for the first time.

[0016] S ( T MO2) 0 This is the altitude value of the transition metal layer in the positive electrode active material before the battery containing the positive electrode active material is charged for the first time.

[0017] Based on embodiments of the present invention, the change in altitude value ΔS of the transition metal layer in the positive electrode active material ( T MO2) is ΔS ( T MO2) Satisfying <0.45 Å.

[0018] Based on embodiments of the present invention, the change in altitude value ΔS of the transition metal layer in the positive electrode active material ( T MO2) is ΔS ( T MO2) The condition <0.40 Å is satisfied.

[0019] Based on embodiments of the present invention, the positive electrode active material satisfies at least one of the following conditions.

[0020] The aforementioned α n m is, α 100 0-α 1 The condition 0 ≤ 0.750° is satisfied.

[0021] In the intrinsic XRD diffraction pattern of the positive electrode active material, the peak intensity ratio of the (003) diffraction peak and the (104) diffraction peak is I (003) / I (104) The range is 1.20-1.60.

[0022] In the intrinsic XRD diffraction pattern of the aforementioned cathode active material, when the 2θ value is 43-46°, the full width at half maximum of the corresponding peak is ψ, and ψ satisfies 0.230° ≤ ψ ≤ 0.260°.

[0023] The medium particle size D of the aforementioned cathode active material 50 For 0.8μm≦D 50 The size must be ≤14.2μm.

[0024] Based on embodiments of the present invention, the positive electrode active material comprises a lithium-containing metal oxide, and the lithium-containing metal oxide has the chemical formula shown in formula (1). Li a Ni x Co y Mn z M b O2(1)

[0025] Equation I includes the following conditions: 0.9≦a≦1.2, 0.3≦x<0.99, 0.01≦y≦0.5, 0.01≦z≦0.5, 0≦b≦0.2, and M is selected from at least one of Al, Zr, Y, Ti, Nb, Cr, Er, Mg, Ba, V, Sr, Ta, Mo, W, and Ce.

[0026] According to an embodiment of the present invention, the positive electrode active material further comprises a coating layer, the coating layer being provided on the surface of the lithium-containing metal oxide.

[0027] According to embodiments of the present invention, the coating layer comprises an oxide containing at least one element of Al, B, Si, W, Ti, and Ce.

[0028] In a second aspect of the present invention, a method for producing a positive electrode active material is proposed. The production method is

[0029] (1) A step of mixing a cathode active material precursor and a lithium source with a first dopant and performing an initial sintering to obtain a first cathode active material intermediate,

[0030] (2) The first cathode active material intermediate is mixed with a second dopant and a second sintering is performed to obtain a second cathode active material intermediate,

[0031] (3) The process includes the step of mixing the second cathode active material intermediate with a coating agent and performing a third sintering to obtain the second cathode active material.

[0032] This manufacturing method utilizes a three-stage sintering process to maximize the structural stability of the cathode active material itself and to suppress the phenomenon of initial mixing of Li / Ni lattice positions in the cathode active material within a certain range. In addition, it incorporates the shift angle α of the (10⁴) diffraction peak of the cathode active material and the height change value S of the transition metal layer. ( T MO2) We demonstrate that this reduces the phenomenon of Li / Ni being mixed into the lattice during the circulation process, thereby optimizing performance.

[0033] Based on the embodiment of the present invention, the initial sintering is performed at T1 for 1.5 to 3 hours, then the temperature is raised to T2 and sintered for 8 to 12 hours, satisfying the conditions that the sintering atmosphere is oxygen.

[0034] The temperature T1 is 300-500°C, the temperature T2 is 650-1100°C, and the oxygen flow rate is 150-200 L / (L·h).

[0035] Based on the embodiment of the present invention, the second sintering is performed at T3 for 6 to 8 hours, satisfying the conditions that the sintering atmosphere is oxygen.

[0036] The above T3 satisfies T2 - 50 × (1.9 - n) ≤ T3 ≤ T2 - 50 × (1.1 - n), where n is the ratio of the total molar amount of doped metal elements in the second dopant to the total molar amount of Ni, Co, and Mn elements in the positive electrode active material precursor, and the oxygen flow rate is 150-200 L / (L·h).

[0037] Based on the embodiment of the present invention, the third sintering satisfies the condition of sintering at 270-350°C for 6-12 hours.

[0038] Based on the embodiments of the present invention, the cathode active material precursor is a nickel-cobalt-manganese cathode material precursor.

[0039] Based on embodiments of the present invention, the lithium source is selected from lithium hydroxide, lithium carbonate, and lithium acetate.

[0040] Based on embodiments of the present invention, the first dopant and the second dopant are each independently selected from one of carbonates, hydroxides, oxides, and acetates that can produce at least one element from Al, Zr, Y, Ti, Nb, Cr, Er, Mg, Ba, V, Sr, Ta, Mo, W, and Ce.

[0041] Based on embodiments of the present invention, the coating agent is selected from oxides that can emit at least one element of Al, B, Si, W, Ti, and Ce.

[0042] Based on the embodiments of the present invention, the positive electrode active material has the chemical formula shown in formula (2). Li a Ni x Co y Mn z M b O2@M' (2)

[0043] The formula includes the following conditions: 0.9≦a≦1.2, 0.3≦x<0.99, 0.01≦y≦0.5, 0.01≦z≦0.5, 0≦b≦0.2, M is selected from at least one element of Al, Zr, Y, Ti, Nb, Cr, Er, Mg, Ba, V, Sr, Ta, Mo, W, and Ce, M' is any one element of Al, B, Si, W, Ti, and Ce, and M' is the base Li a Ni x Co y Mn z M b It coats the surface of O2.

[0044] In a third embodiment of the present invention, a positive electrode sheet is proposed. The positive electrode sheet includes a positive electrode active material described in the first embodiment, or a positive electrode active material manufactured according to the manufacturing method described in the second embodiment.

[0045] In the fourth embodiment of the present invention, a battery is proposed. The battery comprises the positive electrode sheet described in the third embodiment. The battery has excellent circulation performance.

[0046] In the fifth aspect of the present invention, a power consumption device is proposed. The power consumption device comprises the battery described in the fourth aspect. [Effects of the Invention]

[0047] Additional aspects and advantages of the present invention are partially shown in the following description, become apparent from the following description, or become apparent through the practice of the present invention. [Modes for carrying out the invention]

[0048] Examples of the present invention are described in detail below. The following examples are illustrative and are used only to interpret the present invention and do not limit it.

[0049] Furthermore, terms such as "first" and "second" are used solely for descriptive purposes and do not suggest or indicate relative importance, nor do they suggest the number of technical features. This ensures that features limited by "first" or "second" imply or indicate at least one such feature. Unless otherwise explicitly stated, "multiple" in the description of this invention means at least two, for example, two or three.

[0050] The “Examples” described herein mean at least one embodiment that is included in the present invention in combination with a particular feature, structure, and property. Each “Example” described herein does not necessarily refer to the same embodiment, and is either independent of other embodiments or is not an alternative embodiment. Those skilled in the art will understand, both explicitly and implicitly, that the “Examples” described herein may be combined with other embodiments.

[0051] The "range" described in this invention is limited by a lower and upper limit, and the added range is constrained by the setting of the lower and upper limits, which define specific limits. The range limited in this way may or may not include the endpoints, and any combination is possible, that is, any lower limit can be combined with any upper limit to form a range. For example, if we list the ranges 60-120 and 80-110 for a particular parameter, we understand that the ranges 60-110 and 80-120 can be conceived. In addition, if we list the minimum range values ​​1 and 2, and the maximum range values ​​3, 4 and 5, we can conceive of the ranges 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In this invention, unless otherwise specified, the numerical range "ab" is an abbreviation for any combination of real numbers between a and b, and both a and b are real numbers. For example, the numerical range "0-5" refers to all real numbers between "0-5" listed herein, and "0-5" is an abbreviation for combinations of these numbers only. In addition, when a parameter is described as an integer ≥ 2, this is equivalent to explicitly specifying integers such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0052] Unless otherwise specified, all embodiments of the present invention, as well as optional embodiments, may be combined with each other to form new technical means.

[0053] Unless otherwise specified, all technical features of the present invention, as well as selectable technical features, may be combined with each other to form new technical means.

[0054] Unless otherwise specified, all steps of the present invention can be executed in sequence or randomly, preferably in sequence. For example, when the method includes step (a) and step (b), the method can be executed in sequence according to the order of step (a)-step (b), or the method can be executed in sequence according to the order of step (b)-step (a). For example, when the method further includes step (c), the method can be executed in sequence according to the order of step (a)-step (b)-step (c), or the method can be executed in sequence according to the order of step (a)-step (c)-step (b), or the method can be executed in sequence according to the order of step (c)-step (a)-step (b).

[0055] In the first aspect of the present invention, a cathode active material is proposed. The offset angle of the diffraction peak of (104) of the cathode active material is α n m is.

[0056] n is the number of charging cycles of the battery including the cathode active material and is an integer.

[0057] m% is the percentage of the charging capacity when the battery is charged for the nth time to the total capacity of the battery.

[0058] α n m is the 2θ value corresponding to the diffraction peak of (104) in the XRD diffraction pattern of the anode active material when the percentage of the charging capacity when the battery is charged for the nth time to the total capacity of the battery is m%.

[0059] α n m is α 100 50 -α 100 0≦0.250° and α 100 100 -α 100 0≦1.500° is satisfied.

[0060] In the prior art, high-nickel ternary cathode materials are widely used, but there are problems with the instability of this crystal structure. In particular, the phenomenon of mixing Li / Ni lattice positions is frequently observed in high-nickel ternary cathode materials. In addition, during the repeated charge-discharge process of high-nickel ternary cathode materials, as Li + repeatedly intercalates and deintercalates, it changes according to the changes in the Li layer and the valence state of transition metal ions under the interaction between the transition metal ions and the oxygen layer. The Li layer cannot return to its original state before and after charge-discharge, which causes an irreversible change in the relative position between the transition metal layer and the oxygen layer. As the number of charge-discharge cycles increases, this change gradually deepens, thus severely affecting the stability of the transition metal layer and the life of the material in terms of the structure of the material itself. The structure of the cathode material intuitively appears in the XRD characteristics with the changes in charge-discharge. The

[0104] peaks representing the hexagonal structure and the cubic structure shift to the right as lithium escapes, but when lithium returns to the lithium layer, the

[0104] peak may move back to the initial position. However, due to the structural changes caused by the phenomenon of mixing Li / Ni in the lattice position, it cannot return to the initial position. Therefore, by detecting the deviation angle α n <000009又は>of the (104) diffraction peak of the cathode active material, the structural stability and electrochemical cycling performance of the material during the cycling process can be directly reflected. The deviation angle α n m of the (104) diffraction peak of the cathode active material 100 50 is such that when at least one of the conditions of α 100 0≦0.250° and α 100 100 -α 100 0≦1.500° is satisfied, it indicates that this material has better structural stability and better cycling performance.

[0061] In a specific embodiment of the present invention, n in the deviation angle α n m of the (104) diffraction peak is the number of charge-discharge cycles of the battery including the cathode active material. There is no special restriction on the value of n, and those skilled in the art can select according to actual needs. n is usually an integer from 0 to 100, excluding 0. As some specific examples, n is 1, 50, 100, etc.

[0062] In specific embodiments of the present invention, m% is the percentage ratio of the total capacity of the battery to the charge capacity when the battery is charged for the nth time. The value of m is usually between 0 and 100, and specific examples of m are 0, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, etc.

[0063] In a specific embodiment of the present invention, α n m This is the 2θ value corresponding to the (10⁴) diffraction peak in the XRD diffraction pattern of the anode active material when the ratio of the charged capacity to the total capacity of the battery at the nth charge is m%, and is the horizontal coordinate corresponding to the (10⁴) diffraction peak in the XRD diffraction pattern. The position of the (10⁴) diffraction peak in the XRD diffraction pattern of the positive electrode active material is generally between [43°, 49°], and therefore the value of α is the 2θ value corresponding to the highest peak appearing between [43°, 49°] in the horizontal coordinate of the XRD diffraction pattern of the positive electrode active material.

[0064] In a specific embodiment of the present invention, the shift angle α of the (104) diffraction peak of the cathode active material is determined by XRD diffraction testing. n m It is possible to obtain the required results, and there are no special restrictions on the test method; those skilled in the art can select according to their actual needs. For example, a lithium-ion battery is prepared with the cathode active material according to the current method, and after repeating full charge and full discharge at 45°C with a current of 1C n-1 times, it is charged to m%, and the cathode active material is tested in full spectrum using an XRD diffractometer. There are no special restrictions on the test conditions of the XRD diffractometer; those skilled in the art can select according to their actual needs. For example, the test conditions are as follows: The operating temperature is 21±5℃, the humidity is ≤65%, the cooling water circulator temperature is 23±1℃, the water pressure is 0.36MPa, the refrigerant high pressure is 0.8-1.8MPa, the refrigerant low pressure is 0.4-0.7MPa, the scan speed is 5° / min, the starting angle is 10.0000, the ending angle is 90.0000, the sampling W is 0.0200, and the rotation speed of the automatic turntable is 60° / min.

[0065] In a specific embodiment of the present invention, the (104) diffraction peak shift angle α of the positive electrode active material n m is α 100 0-α 1 If the condition 0 ≤ 0.750° is also satisfied, it indicates that this cathode active material has superior structural stability and circulation performance.

[0066] A specific embodiment of the present invention: The degree of change value ΔS of the transition metal layer of the positive electrode active material. ( T MO2) is ΔS ( T MO2) Satisfying <0.50 Å. ΔS ( T MO2) =S ( T MO2) 0 -S ( T MO2) 1 .

[0067] ΔS ( T MO2) This is the change in altitude of the transition metal layer in the positive electrode active material of the battery containing the positive electrode active material when it is first fully charged and before charging.

[0068] S ( T MO2) 1 This is the altitude value of the transition metal layer in the positive electrode active material when the battery containing the positive electrode active material is fully charged for the first time.

[0069] S ( T MO2) 0 This is the altitude value of the transition metal layer in the positive electrode active material before the battery containing the positive electrode active material is charged for the first time.

[0070] The altitude of the transition metal layer in the positive electrode active material refers to the distance between the transition metal layer and the adjacent oxygen layer in the crystal structure of the positive electrode active material. The altitude value of the transition metal layer affects the structural stability of the positive electrode active material, its lithium ion embedding and evacuation ability, electrochemical performance, and safety. If the change in altitude of the transition metal layer in the positive electrode active material is too large, the material cannot maintain stability during many charge-discharge processes, and the material's lifespan is significantly shortened. If the change in altitude of the transition metal layer in the positive electrode active material satisfies the above conditions, the structure of the positive electrode active material itself is Li + This demonstrates good stability during escape.

[0071] Specifically, ΔS ( T MO2) is the equation ΔS ( T MO2) = S ( T MO2) 0 - S ( T MO2) 1 It can be calculated by S. ( T MO2) 1 This is the hardness value of the transition metal layer in the positive electrode active material from the initial charge of the battery until it is fully charged. ( T MO2) 0 This is the initial transition metal layer elevation value of the anodic active material, i.e., the intrinsic transition metal layer elevation value of the positive electrode active material. The elevation value and changes of the transition metal layer can be measured using techniques such as XRD, i.e., S ( T MO2 )1 and S ( T MO2) 0 These results are obtained by performing XRD diffraction tests on appropriate cathode active materials and combining them with calculations for precise XRD correction.

[0072] Specifically, S ( T MO2) 1 This refers to the altitude of the transition metal layer in the positive electrode active material, obtained by performing an XRD diffraction test on the positive electrode material while the battery containing the positive electrode active material was fully charged with a current of 1C, and then performing a precision correction. (T MO2) 0 This refers to the degree of the transition metal layer obtained by precision correction after performing an XRD diffraction test on the positive electrode active material before the battery containing the positive electrode active material is first charged. The manufacturing of the battery containing the positive electrode active material can be done using general manufacturing methods without any special restrictions. The precision correction process is carried out by Rietveld full-spectrum fitting. There are no special restrictions on the corresponding XRD test conditions, and those skilled in the art can select them according to their actual needs. For example, the test conditions are the same as the (10⁴) diffraction peak shift angle α nm described above. The operating temperature is 21±5℃, the humidity is ≤65%, the cooling water circulator temperature is 23±1℃, the water pressure is 0.36MPa, the refrigerant high pressure is 0.8-1.8MPa, the refrigerant low pressure is 0.4-0.7MPa, the scan speed is 5° / min, the starting angle is 10.0000, the ending angle is 90.0000, the sampling W is 0.0200, and the rotation speed of the automatic turntable is 60° / min.

[0073] In a specific embodiment of the present invention, the degree of change of the transition metal layer in the positive electrode active material ΔS ( T MO2) is ΔS ( T MO2) <0.45 Å, preferably ΔS ( T MO2) The condition satisfies <0.40 Å. This indicates that the positive electrode active material has better structural stability during the charge-discharge process.

[0074] In specific embodiments of the present invention, the positive electrode active material satisfies at least one of the following conditions.

[0075] The aforementioned α n m is, α 100 0-α 1 The condition 0 ≤ 0.750° is satisfied. This indicates that the positive electrode active material has better structural stability during the charge-discharge process.

[0076] In the intrinsic XRD diffraction pattern of the positive electrode active material, the peak intensity ratio of the (003) diffraction peak and the (104) diffraction peak is I (003) / I (104) The value is 1.20-1.60. This indicates a low degree of Li / Ni integration into the lattice positions of the positive electrode active material. The intrinsic XRD diffraction pattern of the positive electrode active material should be understood as the diffraction pattern obtained by performing an XRD test on the positive electrode active material before the first charge of the battery containing the positive electrode active material.

[0077] In the intrinsic XRD diffraction pattern of the aforementioned cathode active material, when the 2θ value is 43-46°, the full width at half maximum of the corresponding peak is ψ, and ψ satisfies 0.230° ≤ ψ ≤ 0.260°. This indicates that the cathode active material has better crystallinity.

[0078] The medium particle size D of the aforementioned cathode active material 50 For 0.8μm≦D 50 The condition ≤14.2 μm is satisfied. This indicates that the cathode active material has excellent cycling performance.

[0079] Based on embodiments of the present invention, the positive electrode active material comprises a lithium-containing metal oxide, and the lithium-containing metal oxide has the chemical formula shown in formula (1). Li a Ni x Co y Mn z M b O2(1)

[0080] The formula includes the following conditions: 0.9≦a≦1.2, 0.3≦x<0.99, 0.01≦y≦0.5, 0.01≦z≦0.5, 0≦b≦0.2, and M is selected from at least one of Al, Zr, Y, Ti, Nb, Cr, Er, Mg, Ba, V, Sr, Ta, Mo, W, and Ce.

[0081] The positive electrode active material achieves good structural stability during the circulation process, thereby enabling the battery containing it to have good circulation performance.

[0082] Specifically, the positive electrode active material may have the chemical formula shown in formula (2). Li a Ni x Co y Mn z M b O2@M' (2)

[0083] The formula includes the following conditions: 0.9≦a≦1.2, 0.3≦x<0.99, 0.01≦y≦0.5, 0.01≦z≦0.5, 0≦b≦0.2, M is selected from at least one element of Al, Zr, Y, Ti, Nb, Cr, Er, Mg, Ba, V, Sr, Ta, Mo, W, and Ce, M' is any one element of Al, B, Si, W, Ti, and Ce, and M' is the base Li a Ni x Co y Mn z M b It coats the surface of O2.

[0084] This positive electrode active material may include a doped nickel-cobalt-manganese active material and a coating layer on at least a portion of its surface, thereby giving the positive electrode active material excellent structural stability and corrosion resistance to the electrolyte. The coating layer contains an oxide containing at least one of Al, B, Si, W, Ti, and Ce. The positive electrode active material also includes secondary particles formed by the aggregation of primary particles.

[0085] In a second aspect of the present invention, a method for producing a positive electrode active material is proposed. The production method includes the following steps.

[0086] (1) The cathode active material precursor and lithium source are mixed with the first dopant, and the first sintering is performed to obtain the first cathode active material intermediate.

[0087] Based on the embodiments of the present invention, the initial sintering is performed by sintering at T1 for 1.5 to 3 hours, then raising the temperature to T2 and sintering for 8 to 12 hours, satisfying the conditions that the sintering atmosphere is oxygen.

[0088] T1 is 300-500°C, for example, 300°C, 400°C, 500°C, etc. The sintering time at this temperature is 1.5-3 hours, for example, 1.5 hours, 2 hours, 2.5 hours, 3 hours, etc. T2 is 650-1100°C, for example, 650°C, 700°C, 750°C, 800°C, 850°C, 900°C, 950°C, 1000°C, 1050°C, 1100°C, etc. The sintering time at this temperature is 8-12 hours, for example, 8 hours, 9 hours, 10 hours, 11 hours, 12 hours, etc. The oxygen flow rate is 150-200 L / (L·h), and may be, for example, 150 L / (L·h), 160 L / (L·h), 170 L / (L·h), 180 L / (L·h), 190 L / (L·h), 200 L / (L·h), etc. The oxygen flow rate described herein refers to the volume of oxygen per unit volume of the container and per unit time, and the unit is L / (L·h).

[0089] Specifically, the initial sintering may include pre-sintering at a constant temperature or regular variable temperature for 1.5-3 hours at 300-500°C (for example, raising the temperature to 400°C at a heating rate of 1-10°C / s followed by a constant temperature pre-treatment for 3 hours, or raising the temperature from room temperature to 400°C in 3 hours at a constant rate), and firing lithium at a constant temperature (650-1100°C) for 8-12 hours.

[0090] Based on a specific embodiment of the present invention, the cathode active material precursor is a nickel-cobalt-manganese cathode material precursor. Furthermore, there are no special limitations on this manufacturing method, and it does not affect the subsequent production of the cathode active material. Those skilled in the art can select it according to the actual situation. For example, a mixed salt solution of nickel salt, cobalt salt, and manganese salt, as well as a precipitant and a complexing agent solution, can be prepared according to a preset molar ratio, injected into a reaction vessel, and the reaction can be carried out while controlling the ammonia concentration, reaction temperature, stirring speed, pH, etc. After the reaction is complete, the cathode active material precursor can be obtained through maturation, separation, washing, and drying. There are no special limitations on the types of nickel salt, cobalt salt, manganese salt, precipitant, and complexing agent, and those skilled in the art can flexibly select them according to the actual situation. For example, the nickel salt, cobalt salt, and manganese salt may contain, but are not limited to, sulfates of the corresponding metals; the precipitant may, but are not limited to, sodium hydroxide; and the complexing agent may, but are not limited to, aqueous ammonia. Similarly, the ammonium concentration, reaction temperature, stirring speed, and pH can also be reasonably selected according to the manufacturing situation. For example, the ammonium concentration is 2-8 g / L, the reaction temperature is 60-80°C, the stirring speed is 400-800 rpm / min, and the pH is 10-12.

[0091] Based on specific embodiments of the present invention, there are no special limitations on the specific type of lithium source, and those skilled in the art can select one according to the practical circumstances. For example, the lithium source includes at least one of lithium hydroxide, lithium carbonate, and lithium acetate.

[0092] Based on specific embodiments of the present invention, there are no special limitations on the specific type of the first dopant, and those skilled in the art can select it according to their actual needs. Preferably, the first dopant includes, but is not limited to, at least one of carbonates, hydroxides, oxides, and acetic acids containing at least one element from Al, Zr, Y, Ti, Nb, Cr, Er, Mg, Ba, V, Sr, Ta, Mo, W, and Ce.

[0093] (2) The first cathode active material intermediate is mixed with the second dopant, and a second sintering is performed to obtain the second cathode active material intermediate.

[0094] Based on the embodiment of the present invention, the second sintering is performed at T3 for 6 to 8 hours (for example, 6, 7, or 8 hours), satisfying the condition that the sintering atmosphere is oxygen.

[0095] The above T3 satisfies T2 - 50 × (1.9 - n) ≤ T3 ≤ T2 - 50 × (1.1 - n), where n is the ratio of the total molar amount of doped metal elements in the second dopant to the total molar amount of Ni, Co, and Mn elements in the positive electrode active material precursor, and the oxygen flow rate is 150-200 L / (L·h), and can be, for example, 150 L / (L·h), 160 L / (L·h), 170 L / (L·h), 180 L / (L·h), 190 L / (L·h), 200 L / (L·h), etc.

[0096] Furthermore, the temperature T3 at this stage should not be too high. The essence of this process is to enrich the material with elements that can stabilize its structural properties, both internally and externally, thereby doping the material and further stabilizing its structure. If the temperature is too high, the ions added in this process will disperse uniformly, and if it exceeds the sintering temperature, the crystals will grow excessively, increasing the degree of crystallinity and making it more difficult to incorporate Li / Ni into the lattice. If the temperature of the second sintering is too low, the ions added in this process will concentrate excessively on the surface, which can affect the material's capacity or reduce its conductivity. In addition, insufficient reaction at this stage will cause some of the main components to disperse again and enrich the material externally, but recrystallization may not occur in a timely manner, affecting the outcome of the secondary sintering.

[0097] Specifically, the second sintering process satisfies the condition of heating to T3 at a heating rate of 3-8°C / s and processing at a constant temperature for 6-8 hours.

[0098] Based on specific embodiments of the present invention, there are no special limitations on the specific type of the second dopant, and it may be the same as or different from the first dopant in step (1), and those skilled in the art can select it according to their actual needs. Preferably, the second dopant includes, but is not limited to, at least one of carbonates, hydroxides, oxides and acetic acids containing at least one element from Al, Zr, Y, Ti, Nb, Cr, Er, Mg, Ba, V, Sr, Ta, Mo, W and Ce.

[0099] Based on specific embodiments of the present invention, the ratio n of the total molar amount of doped elements in the second dopant to the total molar amount of Ni, Co, and Mn elements in the cathode active material precursor does not exceed 1.5 mol%. This stabilizes the surface structure of the material, enhances the material's stability, and does not affect capacity utilization.

[0100] (3) The second cathode active material intermediate is mixed with a coating agent, and the second cathode active material is obtained by performing a third sintering.

[0101] Based on the embodiment of the present invention, the third sintering satisfies the condition of sintering at 270-350°C (for example, 270°C, 300°C, 330°C, 350°C, etc.) for 6-12 hours (6h, 7h, 8h, 9h, 10h, 11h, 12h, etc.).

[0102] Specifically, the third sintering process satisfies the condition of obtaining the positive electrode active material by raising the temperature to 270-350°C at a constant rate of 2-5°C / min and then firing at a constant temperature for 6-12 hours.

[0103] Based on specific embodiments of the present invention, there are no particular limitations on the specific type of coating agent, and those skilled in the art can select one according to their actual needs. Preferably, the coating agent comprises an oxide containing at least one of the elements Al, B, Si, W, Ti, and Ce.

[0104] Based on the embodiments of the present invention, the positive electrode active material has the chemical formula shown in formula (2). Li a Ni x Co yMn z M b O2@M' (2)

[0105] The formula includes the following conditions: 0.9≦a≦1.2, 0.3≦x<0.99, 0.01≦y≦0.5, 0.01≦z≦0.5, 0≦b≦0.2, M is selected from at least one element of Al, Zr, Y, Ti, Nb, Cr, Er, Mg, Ba, V, Sr, Ta, Mo, W, and Ce, and M' is any one element of Al, B, Si, W, Ti, and Ce, and M' coats the surface of the substrate LiaNixCoyMnzMbO2.

[0106] In a third embodiment of the present invention, a positive electrode sheet is proposed. The positive electrode sheet includes a positive electrode active material described in the first embodiment, or a positive electrode active material manufactured according to the manufacturing method described in the second embodiment.

[0107] The positive electrode sheet typically includes a positive electrode current collector and a positive electrode active material layer placed on the positive electrode current collector, the positive electrode active material layer containing a positive electrode active material.

[0108] The positive electrode current collector may be a conventional metal foil or a composite current collector (for example, a composite current collector made by placing a metal material on a polymer substrate). For example, the positive electrode current collector includes at least one of copper foil, aluminum foil, nickel foil, stainless steel foil, stainless steel mesh, or carbon-coated aluminum foil.

[0109] The positive electrode active material is a positive electrode active material described in the first embodiment of the present invention, or a positive electrode active material manufactured according to the method described in the second embodiment.

[0110] The positive electrode active material layer optionally includes a conductive agent and an adhesive. The conductive agent is used to improve the conductivity of the positive electrode active material layer, and the adhesive is used to firmly bond the positive electrode active material and the adhesive to the positive electrode current collector. The present invention does not impose specific limitations on the types of conductive agents and adhesives, and they can be selected according to actual needs.

[0111] For example, the conductive agent includes at least one of superconducting carbon, acetylene black, carbon black, cotton black, carbon nanoparticles, carbon nanotubes, graphene, and carbon nanofibers. The adhesive includes at least one of polyvinylidene fluoride (PVDF), vinylene fluoride copolymer, and chemically modified derivatives thereof (e.g., chemical modification with carboxylic acid, acrylic acid, acrylonitrile, etc.).

[0112] All of these materials are available through commercial means.

[0113] In the fourth embodiment of the present invention, a battery is proposed. The battery comprises the positive electrode sheet described in the third embodiment. The battery has excellent circulation performance.

[0114] A battery refers to a device that can continue to be used by reactivating its active materials through charging after discharge.

[0115] Naturally, the battery proposed in this invention is a lithium-ion battery.

[0116] Typically, a battery consists of a positive electrode sheet, a negative electrode piece, a diaphragm, and an electrolyte. During the charging and discharging process, active ions move back and forth between the positive electrode sheet and the negative electrode piece, entering and exiting. The diaphragm is placed between the positive electrode sheet and the negative electrode piece and serves as a separator. The electrolyte plays a role in transporting ions between the positive electrode sheet and the negative electrode piece.

[0117] [Negative electrode piece] In a battery, the negative electrode piece typically includes a negative electrode current collector and a negative electrode active material layer placed on the negative electrode current collector, and the negative electrode active material layer includes a negative electrode active material.

[0118] The negative electrode current collector is typically a structure or component that collects electric current, and the negative electrode current collector can be made of various materials applicable to the negative electrode current collector of a lithium secondary battery in the art, and may utilize conventional metal foil or composite current collectors (for example, composite current collectors made by placing metal materials on a polymer substrate). For example, the negative electrode current collector may utilize copper foil or lithium chips.

[0119] The specific types of the anode active material are not limited, and active materials usable in battery anodes and known in the art may be used, and those skilled in the art can select according to their actual needs. For example, the anode active material includes, but is not limited to, a combination of one or more of graphite, soft carbon, hard carbon, carbon fibers, intermediate-phase carbon microspheres, silicon-based materials, tin-based materials, lithium titanate, and other metals that can form alloys with lithium. The graphite is selected from a combination of one or more of artificial graphite, natural graphite, and modified graphite; the silicon-based materials are selected from a combination of one or more of elemental silicon, silicon oxide, silicon-carbon composites, and silicon alloys; and the tin-based materials are selected from a combination of one or more of elemental tin, tin oxide, and tin alloys. All of these materials are available by commercial means.

[0120] In some implementations, the negative electrode active material includes a silicon-based material to further increase the energy density of the battery.

[0121] The negative electrode active material layer typically includes an adhesive, a conductive agent, and other selectable auxiliary agents.

[0122] For example, the conductive agent includes at least one of superconducting carbon, acetylene black, carbon black, cotton black, carbon nanoparticles, carbon nanotubes, graphene, and carbon nanofibers.

[0123] For example, adhesives may contain one or more of the following: styrene-butadiene rubber (SBR), water-based acrylic resin, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), ethylene vinyl acetate (EVA), polyvinyl alcohol (PVA), and polyvinyl butyral (PVB).

[0124] For example, other selectable additives may include thickeners, dispersants (e.g., carboxymethylcellulose sodium CMC-Na), and PTC thermal resistance materials.

[0125] [Electrolyte] The aforementioned electrolyte may contain an electrolyte salt and a solvent.

[0126] For example, the electrolyte salts include one or more of the following: lithium hexafluoride phosphate (LiPF6), lithium tetraborate (LiBF4), lithium hyperchlorate (LiClO4), lithium hexafluoride arsenate (LiAsF6), lithium methylsulfonyl difluoride (LiFSI), lithium bis-trimethylsulfonyl difluoride (LiTFSI), lithium methanesulfonate trifluoride (LiTFS), lithium borate difluoride oxalate (LiDFOB), lithium borate dioxalate (LiBOB), lithium phosphate difluoride (LiPO2F2), lithium disoxalate phosphate difluoride (LiDFOP), and lithium tetraoxalate phosphate (LiTFOP).

[0127] For example, the solvent includes at least one of ethylene carbonate (EC), propylene carbonate (PC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), ethyl propyl carbonate (EPC), butyl carbonate (BC), fluorinated ethylene carbonate (FEC), methyl formate (MF), methyl acetate (MA), ethyl acetate (EA), propyl acetate (PA), methyl propionate (MP), ethyl propionate (EP), propionate (PP), methyl butyrate (MB), ethyl butyrate (EB), 1,4-butyrolactone (GBL), sulfolane (SF), dimethyl sulfone (MSM), methyl ethyl sulfone (EMS), and diethyl sulfone (ESE).

[0128] In some applications, the electrolyte further includes additives. For example, the additives may include negative electrode film-forming additives, positive electrode film-forming additives, or additives to improve specific battery performance, such as overcharge performance, high-temperature performance, and low-temperature performance.

[0129] [diaphragm] The present invention does not impose any special limitations on the diaphragm, and any porous isolation membrane with electrochemical and mechanical stability that is widely known can be selected according to the actual demand. For example, this may include at least one combination of polyethylene, polypropylene, polyvinylidene fluoride, aramid, polyethylene terephthalate, polytetrafluoroethylene, polyacrylonitrile, polyimide, polyamide, polyester, and natural fibers.

[0130] A fifth embodiment of the present invention proposes a power consumption device. The power consumption device comprises a battery as described in the fourth embodiment. Specifically, the battery may be used as a power source for the power consumption device or as a power storage component for the power consumption device. The power consumption device includes, but is not limited to, portable devices (e.g., mobile phones, laptop computers), electric vehicles (e.g., electric cars, hybrid electric cars, plug-in hybrid electric cars, electric bicycles, electric scooters, electric golf carts, and electric trucks), electric trains, ships, satellites, and energy storage systems.

[0131] The technical means of the present invention will now be described through specific examples, but these examples are for illustrative purposes only and do not limit the scope of the invention. Any techniques or conditions not explicitly stated in the examples should be understood in accordance with the techniques or conditions described in the literature in the art or in the product descriptions. Unless the manufacturer is indicated on the required equipment or reagents, they are considered to be commercially available products.

[0132] <Example 1> [Lithium metal oxide Li 1.03 Ni 0.896 Co 0.057 Mn 0.037 Al 0.008 W 0.001 Sr 0.001 Cathode active material Li containing a coating layer containing O2 and element B 1.03 Ni 0.896 Co 0.057 Mn 0.037 Al 0.008 W 0.001 Sr 0.001 [Manufacturing of O2@B] (1) Li 1.03 Ni 0.896 Co 0.057 Mn 0.037 Al 0.008 W 0.001 Sr 0.001According to the stoichiometric ratio of O2, nickel sulfate, cobalt sulfate, and manganese sulfate are mixed and dissolved in pure water to obtain a 2 mol / L mixed salt solution A. An 8 mol / L sodium hydroxide solution is added as precipitating agent solution B, and a 6 mol / L aqueous ammonia solution is added as complexing agent solution C. Solutions A, B, and C are added to the reaction vessel from the input pipes, respectively. The ammonia system concentration is maintained at 6-8 g / L, the reaction system temperature is kept at 60°C, the stirring speed is set to 600 rpm, and the pH of the reaction system is set to 11.3. After the reaction is complete, the precursor material is obtained by maturation, separation, washing, and drying.

[0133] (2) The precursor, lithium hydroxide, aluminum oxide, tungsten oxide, and strontium carbonate are measured according to the molar ratio of 0.99:1.03:0.002:0.001:0.001, then mixed uniformly using a mixer, and sintered at constant temperature in an oxygen furnace with the oxygen flow rate set to 500 L / h. The specific process involves raising the temperature to 300°C (T1) at a constant rate for 3 hours at room temperature, maintaining a constant temperature for 2 hours, then raising the temperature to 780°C (T2) at a constant rate for 6 hours, sintering at constant temperature for 12 hours, and finally allowing it to cool naturally. After cooling, crushing, and sieving, the first cathode active material intermediate is obtained.

[0134] (3) The first cathode active material intermediate is thoroughly mixed with aluminum oxide in a mixer according to a molar ratio of 1:0.002, and then sintered at constant temperature in an oxygen furnace with the oxygen flow rate set to 500 L / h. The specific process is to raise the temperature to 300°C (T1) at a constant rate at room temperature for 3 hours, then maintain a constant temperature for 2 hours, then raise the temperature to 650°C (T3) at a constant rate for 6 hours, sinter at constant temperature for 8 hours, and finally allow to cool naturally. The second cathode active material intermediate is obtained after cooling, crushing, and sieving.

[0135] (4) The second cathode active material intermediate is uniformly mixed with the boric acid powder material in a high-speed mixer according to a molar ratio of 1:0.01, and constant temperature sintering is performed in an oxygen furnace at 350°C with a sintering time set to 10 hours. The cathode active material is obtained after cooling, sieving, and iron removal.

[0136] [Manufacturing of positive electrode sheets] Li manufactured as described above1.03 Ni 0.896 Co 0.057 Mn 0.037 Al 0.008 W 0.001 Sr 0.001 Mix O2@B (9.5 g), acetylene black (0.25 g), and an N-methylpyrrolidone (NMP) solution containing 0.25 g of polyvinylidene fluoride (PVDF) to form a positive electrode paste. Apply the slurry to aluminum foil, dry it, and press-molde it under a pressure of 100 MPa to create a positive electrode sheet with a diameter of 12 mm and a thickness of 120 μm. Place the positive electrode sheet in a vacuum drying box and dry it at 120°C for 12 hours.

[0137] [Manufacturing of negative electrode pieces] The negative electrode uses a piece of Li metal with a diameter of 17 mm and a thickness of 1 mm.

[0138] [Manufacturing of electrolyte solution] A 1.0 mol / L LiPF6 solution is used as the electrolyte, and an equal mixture of ethylene carbonate (EC) and diethyl carbonate (DEC) is used as the solvent.

[0139] [diaphragm] A 25 μm thick porous polyethylene membrane is used as the diaphragm.

[0140] The positive electrode sheet, diaphragm, and negative electrode piece are stacked in order, with the diaphragm placed between the positive electrode sheet and the negative electrode piece to provide isolation, and then the assembly is wound up to obtain the electrode assembly. The electrode assembly is placed inside the outer casing, the prepared electrolyte is injected into the dried secondary battery, and a lithium-ion battery is obtained through vacuum sealing, standing, activation, and shaping processes.

[0141] The lithium-ion batteries containing the positive electrode active material in Examples 2-9 and Comparative Examples 1-5 differed from those in Example 1 in terms of parameters (see Table 1), but were similar in other respects. The chemical formulas of the obtained positive electrode active materials are shown in Table 2. Table 1 [Table 1-1] [Table 1-2] [Table 1-3]

[0142] In Table 1, " / " indicates that it is not added or is absent. Table 2 [Table 2]

[0143] In Table 2, the chemical formula before the @ symbol indicates the composition of the lithium metal oxide in the positive electrode active material, and the part after the @ symbol indicates the main elements in the coating layer.

[0144] Testing and Analysis 1. XRD tests were performed on the cathode active materials of Examples 1-9 and Comparative Examples 1-5, respectively, and the test results are shown in Table 3.

[0145] α 1 100 , α 1 50 , α 1 0, I (003) / I (104) The full width at half maximum is ψ and ΔS ( T MO2) All tests are performed using an X-ray diffractometer (XRD). The specific test conditions are as follows: The working temperature is 21±5℃, the humidity is ≤65%, the temperature of the cooling water circulator is 23±1℃, the water pressure is 0.36MPa, the refrigerant high pressure is 0.8-1.8MPa, the refrigerant low pressure is 0.4-0.7MPa, the scan speed is 5° / min, the starting angle is 10.0000, the ending angle is 90.0000, the sampling W is 0.0200, and the rotation speed of the automatic turntable is 60° / min. XRD diffraction tests are performed on the appropriate cathode active material and combined with calculations for precise XRD correction. ( TMO2) 1 and S ( T MO2) 0 We obtain the equation ΔS, and then, ( T MO2) = S ( T MO2) 1 - S ( T MO2) 0 According to ΔS ( T MO2) Calculate.

[0146] 2. The recycling performance of the lithium-ion batteries of Examples 1-9 and Comparative Examples 1-5 was tested, and the test results are shown in Table 3.

[0147] The test method involves charging and discharging the battery test specimen twice at a current density of 20 mA / g, completing the activation at a cutoff voltage of 3.0-4.3 V. Using the activated battery test specimen, 100 charge-discharge cycles are performed at a temperature of 45°C, a current density of 1C, and a voltage range of 3.0-4.3 V. The circulating performance of the battery test specimen is characterized by the high-temperature capacity retention rate, i.e., the discharge ratio capacity at the 100th cycle / initial discharge ratio capacity × 100%. Table 3 [Table 3-1] [Table 3-2]

[0148] Regarding the results analysis, (1) In Examples 1-9, a positive electrode active material was obtained according to the manufacturing method of the present invention, and α 100 50 -α 100 0 is less than 0.250°, and α 100 100 -α 100 All values ​​of 0 are less than 1,500°, and α 100 0-α 1 0 is less than 0.750°, and ΔS ( T MO2)All of these are less than 0.50 Å, I (003) / I (104) All of these values ​​are in the range of 1.20-1.60, indicating that this material has excellent structural stability. + It exhibits good stability during escape, and batteries containing it have a long cyclic life.

[0149] (2) Comparative Example 1 is compared with Example 7, except that the doping element W is replaced with La. According to Table 3, the change in α nm of the obtained cathode active material and ΔS ( T MO2) and I (003) / I (104) These are all outside the scope of the present invention. In addition, the capacity retention rate of the battery test specimen in Example 1 (89.6%) is lower than that of Example 7 (91.5%), indicating that the selected doping elements described in the present invention are advantageous for the structural stability of the positive electrode active material and the cyclic life of the battery containing it.

[0150] (3) Comparative Example 2 is compared to Example 1 in that the two-stage sintering process in the initial sintering process is changed to a one-stage sintering process. According to Table 3, the change in αnm of the obtained cathode active material and ΔS ( T MO2) and I (003) / I (104) All of these fall outside the scope of the present invention. In addition, the capacity retention rate of the battery test specimen in Comparative Example 2 (89.3%) is lower than that of Example 1 (92.8%), indicating that two-stage sintering during the initial sintering process is more advantageous for the structural stability of the positive electrode active material and the cyclic life of the battery containing it.

[0151] (4) Compared to Example 1, Comparative Example 3 omits the second sintering process. According to Table 3, the α of the obtained cathode active material n m Change value, ΔS ( T MO2) and I (003) / I (104)All of these fall outside the scope of the present invention. In addition, the capacity retention rate of the battery test specimen in Comparative Example 3 (86.6%) is lower than that of Example 1 (92.8%), indicating that the combination of the first and second sintering processes is more advantageous in terms of the structural stability of the positive electrode active material and the cyclic life of the battery containing it.

[0152] (5) Compared to Example 1, Comparative Example 4 is shown in which the sintering temperature in the second sintering process is lowered. According to Table 3, the α of the obtained cathode active material n m Change value, ΔS ( T MO2) and I (003) / I (104) All of these fall outside the scope of the present invention. In addition, the capacity retention rate of the battery test specimen in Comparative Example 4 (88.0%) is lower than that of Example 1 (92.8%), indicating that the combination of the first and second sintering processes is more advantageous in terms of the structural stability of the positive electrode active material and the cyclic life of the battery containing it.

[0153] (6) Compared to Example 1, Comparative Example 5 is shown in which the sintering temperature in the second sintering process is lowered. According to Table 3, the α of the obtained cathode active material n m Change value, ΔS ( T MO2) and I (003) / I (104) All of these fall outside the scope of the present invention. In addition, the capacity retention rate of the battery test specimen in Comparative Example 5 (89.1%) is lower than that of Example 1 (92.8%), indicating that the temperature range of the present invention is more advantageous for the structural stability of the positive electrode active material and the cyclic life of the battery containing it.

[0154] In this specification, the terms “one example,” “several examples,” “example,” “specific example,” or “several examples” mean that the specific features, structures, materials, and properties described in combination with such examples are included in at least one example of the present invention. In this specification, exemplary expressions for the above terms do not necessarily have to target the same example. In addition, specific features, structures, materials, or properties described in any one or more examples can be combined in an appropriate manner. Furthermore, a person skilled in the art can combine different examples and features described herein, provided they are not contradictory.

[0155] Although embodiments of the present invention have already been illustrated, it is possible to understand that the above embodiments are illustrative and do not limit the present invention. Those skilled in the art can modify, alter, substitute, or change the above embodiments within the scope of the present invention.

Claims

1. A positive electrode active material wherein the shift angle of the (104) diffraction peak of the positive electrode active material is α ｎ ｍ Here, n is the number of times the battery containing the positive electrode active material has been charged, n is an integer, m% is the percentage ratio of the charge capacity when the battery is charged for the nth time to the total capacity of the battery, and α ｎ ｍ This is the 2θ value corresponding to the (104) diffraction peak in the XRD diffraction pattern of the positive electrode active material when the ratio of the charge capacity to the total capacity of the battery when the battery is charged for the nth time is m%. Said α ｎ ｍ is α ｎ ｍ where α １００ ５０ -α １００ ０ ≤0.250° and α １００ １００ -α １００ ０ ≤1.500°, characterized in that it is a positive electrode active material.

2. The change in the degree of the transition metal layer in the aforementioned positive electrode active material ΔS （ＴＭＯ２） ΔS （ＴＭＯ２） The condition <0.50 Å is satisfied, where ΔS （ T ＭＯ２） is ΔS （ＴＭＯ２） = S （ＴＭＯ２） ０ -S （ＴＭＯ２） １ And ΔS （ＴＭＯ２） This is the change in the altitude of the transition metal layer in the positive electrode active material of the battery containing the positive electrode active material when it is first fully charged and before charging, and S （ＴＭＯ２） １ S is the altitude of the transition metal layer in the positive electrode active material when the battery containing the positive electrode active material is fully charged for the first time. （ T ＭＯ２） ０ This is the altitude of the transition metal layer in the positive electrode active material before the battery containing the positive electrode active material is first charged. The cathode active material according to feature 1.

3. The change in the degree of the transition metal layer in the aforementioned positive electrode active material ΔS （ＴＭＯ２） ΔS （ＴＭＯ２） The cathode active material according to claim 2, characterized in that it satisfies <0.45 Å.

4. The change in the degree of the transition metal layer in the aforementioned positive electrode active material ΔS （ＴＭＯ２） ΔS （ＴＭＯ２） The cathode active material according to claim 2, characterized in that it satisfies <0.40 Å.

5. The aforementioned α ｎ ｍ is α １００ ０ -α １ ０ The condition that ≤ 0.750° is satisfied, In the intrinsic XRD diffraction pattern, the peak intensity ratio I of the (003) diffraction peak and the (104) diffraction peak （００３） / I （１０４） The condition is that it is 1.20 - 1.

60. When the 2θ value in the intrinsic XRD diffraction pattern is 43-46°, the full width at half maximum of the corresponding peak is ψ, and the condition is that ψ satisfies 0.230° ≤ ψ ≤ 0.260°. Median particle size D ５０ 0.8 μm ≤ D ５０ Satisfying at least one of the conditions ≤ 14.2 μm, The cathode active material according to feature 1.

6. It contains a lithium-containing metal oxide, wherein the lithium-containing metal oxide has the chemical formula shown in formula (1), Li ａ Ni ｘ Co ｙ Mn ｚ M ｂ O ２ (1) Here, 0.9 ≤ a ≤ 1.2, 0.3 ≤ x < 0.99, 0.01 ≤ y ≤ 0.5, 0.01 ≤ z ≤ 0.5, and 0 ≤ b ≤ 0.2, and M is selected from at least one of Al, Zr, Y, Ti, Nb, Cr, Er, Mg, Ba, V, Sr, Ta, Mo, W, and Ce. The positive electrode active material according to any one of claims 1 to 5, characterized by the features described herein.

7. The positive electrode active material according to claim 6, further comprising a coating layer, wherein the coating layer is provided on the surface of the lithium-containing metal oxide.

8. The positive electrode active material according to claim 7, characterized in that the coating layer contains an oxide containing at least one element of Al, B, Si, W, Ti, and Ce.

9. (1) A step of mixing a cathode active material precursor and a lithium source with a first dopant and performing an initial sintering to obtain a first cathode active material intermediate, (2) The first cathode active material intermediate is mixed with a second dopant and a second sintering is performed to obtain a second cathode active material intermediate, (3) The step of mixing the second positive electrode active material intermediate with a coating agent and performing a third sintering to obtain the positive electrode active material, A method for producing a positive electrode active material according to any one of claims 1 to 8.

10. The conditions for the initial sintering are, １ Sinter for 1.5 to 3 hours, T ２ The sintering process involves raising the temperature and sintering for 8 to 12 hours, and the sintering atmosphere is oxygen. Here, the aforementioned T １ The temperature is 300-500°C, and the T ２ The temperature is 650-1100°C, and the oxygen flow rate is 150-200 L / (L·h). The manufacturing method according to claim 9.

11. The conditions for the second sintering are, ３ The sintering process is carried out for 6 to 8 hours, and the sintering atmosphere is oxygen. Here, the aforementioned T ３ ga T ２ -50×(1.9-n)≦T ３ ≦T ２ The equation -50 × (1.1 - n) is satisfied, where n is the ratio of the total molar amount of doped metal elements in the second dopant to the total molar amount of Ni, Co, and Mn elements in the positive electrode active material precursor, and the oxygen flow rate is 150-200 L / (L·h). The manufacturing method according to claim 9.

12. The manufacturing method according to claim 9, characterized in that the conditions for the third sintering include sintering at 270 to 350°C for 6 to 12 hours.

13. The manufacturing method according to claim 9, characterized in that the cathode active material precursor is a nickel-cobalt-manganese cathode material precursor.

14. The manufacturing method according to claim 9, characterized in that the lithium source is selected from lithium hydroxide, lithium carbonate, and lithium acetate.

15. The first dopant and the second dopant are each independently selected from one of carbonates, hydroxides, oxides, and acetates that can provide at least one element from Al, Zr, Y, Ti, Nb, Cr, Er, Mg, Ba, V, Sr, Ta, Mo, W, and Ce. The manufacturing method according to claim 9.

16. The manufacturing method according to claim 9, characterized in that the coating agent is selected from oxides that can provide at least one element of Al, B, Si, W, Ti, and Ce.

17. A positive electrode active material according to any one of claims 1 to 8, or a positive electrode active material manufactured according to the manufacturing method described in any one of claims 9 to 16, A positive electrode sheet characterized by the following features.

18. A battery characterized by comprising the positive electrode sheet described in claim 17.

19. A power consumption device characterized by comprising the battery described in claim 18.

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