High nickel and cobalt-free cathode material capable of double reduction of residual alkali and its manufacturing method

Abstract

In this application, a high nickel and cobalt-free cathode material capable of doubly reducing residual alkali and a method for manufacturing the same are disclosed. The chemical formula of the high nickel and cobalt-free cathode material is Li x Ni y Mn 1-y A z O2, and satisfies 0.75 < y ≤ 0.95, 0.95 ≤ x ≤ 1.15, 0.001 < z ≤ 0.005. In this application, primary reduction of residual alkali can be achieved by water washing. In addition, due to the formation of perovskite in-situ on the material surface, residual lithium in the material can be consumed to achieve secondary reduction of residual alkali. At the same time, a La a Li b CoO3 perovskite coating layer can also be formed. Further, due to the formation of the perovskite coating layer on this cathode material, it has high lithium ion electrical conductivity, good capacity retention ability and rate performance, and high reversibility. The manufactured high nickel and cobalt-free cathode material has low residual alkali, high discharge capacity, good rate performance, and good battery cycle performance.

Description

[Technical Field]

[0001] This application claims priority from Chinese Patent Application No. 202410015280.7, filed on January 5, 2024. The entire text of the above Chinese patent application is incorporated herein by reference.

[0002] This application relates to a cobalt-free cathode material for lithium batteries, and more particularly to a high-nickel, cobalt-free cathode material that can double-reduce residual alkalinity and a method for manufacturing the same. [Background technology]

[0003] As the automotive industry undergoes a paradigm shift toward electrification, rechargeable batteries must also meet future needs. Despite some success, efforts to improve battery performance still face high cost obstacles. These battery cost challenges are primarily related to the rising prices and increasing demand for transition metals (TMs), especially cobalt (Co). Cobalt is a core material component in widely used commercial cathodes, such as LiCoO2 and LiNi x Mn y Co 1-x-y O2, LiNi 0.8 Co 0.15 Al 0.05 O2. In recent years, the economic attractiveness of Co has already been lost. In response to these cost pressures, those skilled in the art are striving to develop low-Co, and even Co-free, cathodes without sacrificing battery performance. Lithium-rich and manganese-rich cathodes, high-voltage spinel LiNi 0.5 Mn 1.5 Although O4 and some possible alternatives, including disordered rock salt, have been highlighted as viable alternatives to cobalt-containing cathodes, their practically unattainable capacity and stability preclude their application in large-scale commercial applications. Therefore, high-Ni, low-Co, or completely Co-free layered cathodes have become a research hotspot in the battery industry.

[0004] However, the higher the nickel content, the more alkaline substances, especially LiOH and Li2CO3, formed on the surface of the positive electrode, which accelerates capacity decay, intensifies structural phase transitions, seriously affects the air stability of the positive electrode material and its processing performance during the pulping and coating processes, and also affects the safety and cyclability during battery use. Therefore, reducing the content of residual alkaline substances on the surface of high-nickel materials is a technical issue that needs to be resolved as soon as possible.

[0005] For example, in CN110148728A, LiNO3, La(NO3)3, and Ti[OCH(CH3)2]4 are added, and after a series of operations, a ternary material coated with LLTO is obtained. The cathode material obtained by this method has good cycling stability and rechargeability. However, because an extra Li source is added in this method, the residual alkalinity of the material cannot be reduced.

[0006] For example, in CN112086638A, a battery cathode material is dispersed in an organic solvent containing a phosphorus-containing organic compound. Liquid-phase mixing or in-situ polymerization results in the phosphorus-containing organic compound being uniformly distributed on the surface of the battery cathode material. During the subsequent sintering process, phosphorus reacts with residual lithium on the surface at high temperatures to generate lithium phosphate in situ, resulting in a lithium phosphate-coated battery cathode material. This avoids the adverse effects of water on the battery cathode material, maintains the structural stability of the battery cathode material, depletes the residual lithium on the surface, reduces alkalinity, and forms a uniform lithium phosphate coating on the surface of the battery cathode material, improving its air stability. However, this method does not effectively improve the electrochemical performance and multiplication performance of the material, and the complex process makes it unsuitable for large-scale production. Therefore, the manufacturing method for high-nickel, cobalt-free cathode materials still needs to be improved. Summary of the Invention

[0007] The main technical problem to be solved by the present application is that, according to the ternary material coated with LLTO obtained by adding LiNO3, La(NO3)3, and Ti[OCH(CH3)2]4 mentioned in the above background art, there is a deficiency that the residual alkali of the material cannot be reduced, and when the surface is coated with lithium phosphate, there is a deficiency that the electrochemical performance cannot be effectively improved. It is to provide a high-nickel and cobalt-free cathode material capable of doubly reducing residual alkali and a manufacturing method thereof while overcoming these deficiencies.

[0008] To achieve the above object, the following technical means are used in the present application. The manufacturing method of the high-nickel and cobalt-free cathode material capable of doubly reducing residual alkali includes the following steps.

[0009] S1: A high-nickel and cobalt-free precursor is sufficiently mixed with a lithium salt and a dopant A to obtain a mixture B; the general formula of the high-nickel and cobalt-free precursor is Ni y Mn 1-y (OH)2, and 0.75 < y ≤ 0.95 is satisfied. The molar ratio of the Li element in the lithium salt to Ni y Mn 1-y (OH)2 is (0.95 - 1.15):1, and the dopant A accounts for 0.1 - 0.5 mol% of the total amount of the lithium salt and Ni y Mn 1-y (OH)². The dopant A is a compound containing at least one selected from Al, Zr, W, Mo, and Nb; S2: The mixture B is subjected to primary sintering, cooling, and crushing according to a first temperature curve under an oxygen atmosphere to obtain a high-nickel and cobalt-free cathode material C; the first temperature curve means that under an oxygen atmosphere, the temperature is first raised to ʙ00 - 850 °C at a heating rate of 3 - 10 °C / min, and when the desired temperature is reached, it is kept warm for 3 - 20 h; S3: The high-nickel and cobalt-free cathode material C is washed with water and subjected to solid-liquid separation to obtain a filter cake; S4: Add the La source and Co source to the filter cake, then put them together into a drying device and dry while rotating. After drying, put the dried product into a mixing device and mix for 10 - 30 min to mix evenly, thus obtaining the high nickel-cobalt-free cathode material D; the total range of the matrix Li after the cathode material is pulverized is 0.2500 - 0.4500 ppm, the La source added to the filter cake accounts for 0.5 - 3 wt%, and the molar ratio of the La element in the La source to the Co element in the Co source is 0.5 - 0.9:1; S5: Perform secondary sintering and cooling according to the second temperature curve on the high nickel-cobalt-free cathode material D under an oxygen atmosphere. After sieving, the chemical formula is Li x Ni y Mn 1-y A z O2, and obtain a high nickel-cobalt-free cathode material whose surface is coated with La a Li b CoO3 perovskite, and satisfy 0.75 < y ≤ 0.95, 0.95 ≤ x ≤ 1.15, 0.001 < z ≤ 0.005; the second temperature curve means that under an oxygen atmosphere, first heat up to 300 - 450 °C at a heating rate of 3 - 7 °C / min, and keep the temperature for 3 - 15 h after reaching the desired temperature.

[0010] Preferably, the lithium salt in S1 is LiOH.

[0011] Preferably, in the washing process of S3, the mass ratio of water to the high nickel-cobalt-free cathode material C is 1 - 3:1, the washing time is 10 - 30 min, and then it is fed into a solid-liquid separation device for solid-liquid separation, and the time is 15 - 30 min.

[0012] Preferably, in S4, the added La source contains at least one selected from La2O3, La(NO3)3, La2(CO3)·8H2O, and the Co source contains at least one selected from Co2O3, Co(OH)2, Co(NO3)2, CoCO3, Co3O4. The particle size range of the La source is 10 - 400 nm, and the particle size range of the Co source is 20 - 300 nm.

[0013] Preferably, in S4, as the drying method, a rotatable drying device such as a tapered screw belt type vacuum mixing dryer is used, the drying temperature is 100 to 200 ° C, and the drying time is 0.5 to 7 h.

[0014] Preferably, in S1, for the mixing of the high nickel and cobalt-free precursor, lithium salt, and dopant A, a high-speed mixer or a planetary ball mill is used. The mixing time in the high-speed mixer is 10 to 30 min, and the mixing time in the planetary ball mill is 3 to 5 h.

[0015] A high nickel and cobalt-free cathode material obtained by the method for producing a high nickel and cobalt-free cathode material capable of doubly reducing residual alkali according to the present application, with the chemical formula Li x Ni y Mn 1-y A z O2, and the surface is coated with La a Li b CoO3 perovskite, which satisfies 0.75 < y ≤ 0.95, 0.95 ≤ x ≤ 1.15, 0.001 < z ≤ 0.005, 0.5 ≤ a ≤ 0.9, and 0.3 ≤ b ≤ 1.5.

[0016] According to the present application, the following beneficial effects can be achieved. In the present application, after washing with water and solid-liquid separation of the high nickel and cobalt-free cathode material substrate, an additive is added to the filter cake to coat the material surface with a La source and a Co source, and then a perovskite coating layer is formed in-situ on the material surface by sintering. In this way, primary reduction of residual alkali can be achieved by washing with water. In addition, since the Li (Li2CO3) required for the synthesis of perovskite by this cathode material is the residual lithium on the surface of the cathode material, the lithium in the material can be consumed to achieve secondary reduction of residual alkali on the surface. Furthermore, the chemical formula is La a Li bIt is also possible to form a perovskite coating layer of CoO3 (abbreviated as LLCO). Furthermore, due to the formation of the perovskite coating layer, this positive electrode material has high lithium-ion electrical conductivity, good capacity retention and rechargeability, and high reversibility. The high-nickel, cobalt-free positive electrode material produced by this method has low residual alkalinity, high discharge capacity, good rechargeability, and good battery cycling performance, making it valuable for a wide range of industrial applications. [Brief explanation of the drawings]

[0017] The drawings in the specification that form a part of this application are intended to provide a further understanding of the application, and the exemplary embodiments and descriptions thereof are intended to explain the application but are not intended to unduly limit the application. The drawings will now be briefly described. [Figure 1] FESEM image of Example 2 of the present application; [Figure 2] 1 is an XRD spectrum of the LLCO coating layer produced in Example 2 of the present application; [Figure 3] 1 is a comparison diagram of the initial charge / discharge curves of button-type half cells according to the present invention and the comparative example; [Figure 4] 1 is a comparison diagram of the capacity retention rate of button-type half cells according to the present invention and the comparative example; [Figure 5] FIG. 2 is a comparison diagram of discharge capacity retention rates at different magnifications of button-type half cells according to an example of the present application and a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0018] It should be particularly noted that the embodiments and features of the embodiments described herein can be combined with each other if no contradiction occurs. The present application will now be described in detail with reference to the accompanying drawings.

[0019] As described in the background art of the present application, in the prior art, there are problems such as the inability to reduce the residual alkali of the material with the ternary material coated with LLTO, and the inability to effectively improve the electrochemical performance by coating the surface with lithium phosphate. To solve the above problems, according to a typical embodiment of the present application, a method for manufacturing a high-nickel and cobalt-free cathode material capable of double reduction of residual alkali has been proposed, and such a manufacturing method includes the following steps: S1: A high-nickel and cobalt-free precursor is sufficiently mixed with a lithium salt and a dopant A to obtain a mixture B; the general formula of the high-nickel and cobalt-free precursor is Ni y Mn 1-y (OH)2, and satisfies 0.75 < y ≤ 0.95. The molar ratio of the Li element in the lithium salt to Ni y Mn 1-y (OH)2 is (0.95 - 1.15):1. The dopant A accounts for 0.1 - 0.5 mol% of the total amount of the lithium salt and Ni y Mn 1-y (OH)2, and the dopant A is a compound containing at least one selected from Al, Zr, W, Mo, and Nb; S2: The mixture B is subjected to primary sintering, cooling, and crushing according to the first temperature curve in an oxygen atmosphere to obtain a high-nickel and cobalt-free cathode material C; the first temperature curve means that in an oxygen atmosphere, the temperature is first raised to 800 - 850 °C at a heating rate of 3 - 10 °C / min, and after reaching the desired temperature, it is kept warm for 3 - 20 h; S3: The high-nickel and cobalt-free cathode material C is washed with water and subjected to solid-liquid separation to obtain a filter cake; S4: An La source and a Co source are added to the filter cake, and then they are both put into a drying device and dried while rotating. After drying, the dried product is put into a mixing device and uniformly mixed to obtain a high-nickel and cobalt-free cathode material D; the La source accounts for 0.5 - 3 wt% of the filter cake, and the molar ratio of the La element in the La source to the Co element in the Co source is 0.5 - 0.9:1; S5: The high-nickel and cobalt-free cathode material D is subjected to secondary sintering and cooling according to the second temperature curve in an oxygen atmosphere, and after sieving, the chemical formula is Li x Ni y Mn 1-y A zWith O2, a high nickel and cobalt-free cathode material with a surface coated with La a Li b CoO3 perovskite was obtained, and 0.75 < y ≤ 0.95, 0.95 ≤ x ≤ 1.15, 0.001 < z ≤ 0.005 were satisfied; The second temperature curve means that first, the temperature is raised to 300 - 450 °C at a heating rate of 3 - 7 °C / min in an oxygen atmosphere, and after reaching the desired temperature, it is kept warm for 3 - 15 h.

[0020] Specifically, first, the high nickel and cobalt-free precursor Ni y Mn 1-y (OH)2 was sufficiently mixed with a lithium salt and dopant A to obtain mixture B. During this process, it was uniformly mixed, and it was ensured that the proportion of the high nickel and cobalt-free precursor, lithium salt, and dopant A at any part was consistent with the theory, and the performance of the sintered material could be made consistent with the index; Then, by subjecting mixture B to primary sintering, cooling, and crushing according to the first temperature curve in an oxygen atmosphere, a high nickel and cobalt-free cathode material C was obtained. During this process, by subjecting mixture B to high-temperature sintering in an oxygen atmosphere, the high nickel and cobalt-free cathode material Li x Ni y Mn 1-y A z O2 was produced; After that, by washing the high nickel and cobalt-free cathode material C with water and performing solid-liquid separation, a filter cake was obtained. By water washing, the residual lithium on the surface of the high nickel and cobalt-free cathode material was effectively removed, the influence of high residual lithium on the material was reduced, the conductivity was increased, the migration of lithium ions was accelerated, and the safety performance of the battery could be improved.

[0021] The La source and Co source are added to the filter cake, and then they are both put into a drying device and dried under rotation. After drying is completed, the dried material is put into a mixing device and mixed uniformly to obtain high-nickel and cobalt-free positive electrode material D. During this process, the filter cake, La source, and Co source are mixed uniformly, ensuring that the proportion of the filter cake, La source, and Co source at any part is consistent with the theory, and the performance of the sintered material can be consistent with the index. Finally, the high-nickel and cobalt-free positive electrode material D is subjected to secondary sintering according to the second temperature curve in an oxygen atmosphere, cooled, and sieved to obtain a material with the chemical formula Li x Ni y Mn 1-y A z O2 and the surface is La a Li b A high-nickel, cobalt-free positive electrode material coated with CoO3 perovskite was obtained. The energy generated during high-speed rotation and mixing before secondary sintering was used to cause a chemical reaction between solid material particles, thereby obtaining perovskite without the need for high-temperature sintering. During this process, high-nickel, cobalt-free positive electrode material D was subjected to secondary sintering in an oxygen atmosphere, forming a perovskite coating layer in situ on the material surface. As a result, the high-nickel, cobalt-free positive electrode material has low residual alkalinity, high discharge capacity, good multiplication performance, and good battery cycling performance.

[0022] In this application, after washing and solid-liquid separation of the high-nickel, cobalt-free cathode material substrate, the surface of the material is coated with La and Co sources by adding additives to the filter cake, and then sintering is performed to form a perovskite coating layer on the surface of the material in situ. In this way, the primary reduction of residual alkali can be achieved by washing with water. In addition, since the Li (Li2CO3) required for the synthesis of perovskite using this cathode material is the residual lithium on the surface of the cathode material, the secondary reduction of residual alkali on the surface can be achieved by consuming the lithium in the material. Furthermore, the chemical formula is La a Li bIt is also possible to form a perovskite coating layer of CoO3 (abbreviated as LLCO). Furthermore, due to the formation of the perovskite coating layer, this positive electrode material has high lithium-ion electrical conductivity, good capacity retention and rechargeability, and high reversibility. The high-nickel, cobalt-free positive electrode material produced by this method has low residual alkalinity, high discharge capacity, good rechargeability, and good battery cycling performance.

[0023] According to a preferred embodiment, the lithium salt in S1 is LiOH. Under the above conditions, the molten lithium hydroxide can be more uniformly and thoroughly mixed with the high-nickel precursor during the sintering process, which can further reduce the residual lithium on the surface and increase the discharge specific capacity of the raw material.

[0024] To further reduce residual alkalinity and reduce deterioration in the cycling performance and capacity of the positive electrode material that may occur due to an excessively high water-to-material ratio and cleaning time, in one preferred embodiment, the mass ratio of water to the high nickel / cobalt-free positive electrode material C in the cleaning process in S3 is 1 to 3:1, and the cleaning time is 10 to 30 minutes, after which the material is sent to a solid-liquid separator for solid-liquid separation, which takes 15 to 30 minutes.

[0025] According to a preferred embodiment, in S4, the La source includes at least one selected from La2O3, La(NO3)3, and La2(CO3) 8H2O, the Co source includes at least one selected from Co2O3, Co(OH)2, Co(NO3)2, CoCO3, and Co3O4, the particle size range of the La source is 10 to 400 nm, and the particle size range of the Co source is 20 to 300 nm. The above-mentioned appropriate particle size ranges allow the La source and Co source to be effectively mixed into the filter cake, resulting in a uniformly mixed high-nickel, cobalt-free cathode material D.

[0026] In order to further dry the filter cake and reduce damage to the morphology and structure of the positive electrode material, according to a preferred embodiment, in S4, the drying temperature is 100 to 200°C and the drying time is 0.5 to 7 hours.

[0027] In one preferred embodiment, in step S1, a high-nickel / cobalt-free precursor, lithium salt, and dopant A are mixed using a high-speed mixer or planetary ball mill, with the mixing time for the high-speed mixer being 10-30 minutes and the mixing time for the planetary ball mill being 3-5 hours. Under these conditions, the high-nickel / cobalt-free precursor is mixed more uniformly with the lithium salt and dopant A, further ensuring that the proportions of the high-nickel / cobalt-free precursor, lithium salt, and dopant A at any given point are consistent with theory, and the performance of the sintered material can be consistent with the index.

[0028] For the purpose of optimizing performance and cost, in one preferred embodiment, in S1, the Li element in the lithium salt and Ni y Mn 1-y The molar ratio to (OH)2 is (1.03-1.08):1.

[0029] In a preferred embodiment, the first temperature curve in step S2 refers to first increasing the temperature to 800-820°C at a rate of 3-5°C / min in an oxygen atmosphere, and then maintaining the temperature for 10-20 hours. Under these conditions, the high-nickel / cobalt-free precursor, lithium salt, and dopant A react at the optimal temperature, potentially improving the performance and index of the material. Sintering temperatures above 820°C improve the crystallinity of the raw material, increasing the crystal grain size and reducing the specific surface area, which is unfavorable for lithium ion escape during charge and discharge. Furthermore, too high a sintering temperature can disrupt the lithium-nickel arrangement, making it difficult to sinter a high-nickel layered raw material with the desired weight ratio. This can also reduce the lithium ion diffusion capacity and specific capacity.

[0030] In order to optimize the reaction temperature and performance, in a preferred embodiment, in S5, the second temperature curve is to first increase the temperature to 300-350°C at a rate of 3-6°C / min under an oxygen atmosphere, and then maintain the temperature for 6-15 hours once the desired temperature is reached.

[0031] According to another typical embodiment of the present application, a high nickel and cobalt-free cathode material is proposed. Such a cathode material is obtained by the method for manufacturing a high nickel and cobalt-free cathode material capable of doubly reducing residual alkali according to the present application described above, and its chemical formula is Li x Ni y Mn 1-y A z O2, the surface of which is coated with La a Li b CoO3 perovskite, satisfying 0.75 < y ≤ 0.95, 0.95 ≤ x ≤ 1.15, 0.001 < z ≤ 0.005, 0.5 ≤ a ≤ 0.9, 0.3 ≤ b ≤ 1.5. Since the manufacturing method according to the present application is used, such a high nickel and cobalt-free cathode material has significantly reduced residual alkali, and significantly improved discharge capacity, rate performance and battery cycle performance.

[0032] Hereinafter, the technical means according to the embodiments of the present application will be clearly and completely described. Needless to say, the embodiments described below are only a part of the embodiments of the present application, not all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative labor shall be included within the protection scope of the present application.

[0033] Example 1 The method for manufacturing a high nickel and cobalt-free cathode material capable of doubly reducing residual alkali includes the following steps.

[0034] Weigh a calculated amount of a high nickel and cobalt-free precursor (Ni 0.90 Mn 0.10 (OH)2), a lithium salt, and an additive A. Here, the lithium salt is LiOH, the additive A is ZrO2, the molar ratio of LiOH to Ni 0.90 Mn 0.10 (OH)2 is 1.03:1, and the molar ratio of LiOH to Ni 0.90 Mn 0.10The ZrO2 content of the total (OH)2 was 0.1 mol%, and then they were added to a high-speed mixer and mixed for 15 minutes. The uniformly mixed material was subjected to primary sintering under an oxygen atmosphere, where it was heated from room temperature to 800°C at a rate of 3°C / min and held at that temperature for 10 hours. After primary sintering, the material was cooled, crushed, and pulverized to obtain the pulverized material, which was then washed with pure water at a mass ratio of 1:1 for 15 minutes, and then sent to a centrifuge for solid-liquid separation for 20 minutes. La2O3 with a particle size range of 10-400 nm and Co2O3 with a particle size range of 20-300 nm were added to the filter cake, where La2O3 accounted for 1 wt% of the filter cake and the molar ratio of La2O3 to Co2O3 was 0.5:1. They were then placed in a tapered screw belt vacuum mixer / dryer for drying, where the drying temperature was 150°C and the drying time was 3 hours, after which the device was rotated. After drying was completed, the dried material was placed in a high-speed mixer and mixed for 15 minutes to achieve uniform mixing. It was then sintered in an oxygen atmosphere, where the temperature was raised from room temperature to 300°C at a rate of 3°C / min and kept at that temperature for 6 hours. Finally, it was naturally cooled to room temperature and sieved, after which the coating layer was found to be La. 0.5 Li 1.5 A sample according to Example 1 was obtained, which is CoO3.

[0035] Example 2 The manufacturing method for high-nickel, cobalt-free cathode materials that can double-reduce residual alkalinity includes the following steps:

[0036] High nickel-cobalt-free precursor (Ni 0.90 Mn 0.10 (OH)2), lithium salt, and additive A were weighed in calculated amounts, where lithium salt was LiOH, additive A was ZrO2, LiOH and Ni 0.90 Mn 0.10 (OH)2 in a molar ratio of 1.05:1, and LiOH and Ni 0.90 Mn 0.10The ZrO2 content was 0.3 mol% of the total (OH)2, and then they were added to a high-speed mixer and mixed for 20 minutes. The uniformly mixed material was subjected to primary sintering under an oxygen atmosphere, where it was heated from room temperature to 820°C at a rate of 5°C / min and held at that temperature for 10 hours. After primary sintering, the material was cooled, crushed, and pulverized to obtain the pulverized material, which was then washed with pure water at a mass ratio of 1.5:1 for 20 minutes. It was then sent to a centrifuge for solid-liquid separation for 20 minutes. La2O3 with a particle size range of 10-400 nm and Co2O3 with a particle size range of 20-300 nm were added to the filter cake, where La2O3 accounted for 2 wt% of the filter cake and the molar ratio of La2O3 to Co2O3 was 0.7:1. They were then placed in a tapered screw belt vacuum mixer / dryer for drying, where the drying temperature was 150°C and the drying time was 3 hours, after which the device was rotated. After drying was complete, the dried material was placed in a high-speed mixer and mixed for 15 minutes to achieve uniform mixing. It was then sintered in an oxygen atmosphere, where the temperature was raised from room temperature to 350°C at a rate of 6°C / min and kept at that temperature for 6 hours. Finally, it was naturally cooled to room temperature and sieved, after which the coating layer was found to be La. 0.7 Li 0.9 A sample according to Example 2 was obtained, which is CoO3.

[0037] Example 3 The manufacturing method for high-nickel, cobalt-free cathode materials that can double-reduce residual alkalinity includes the following steps:

[0038] High nickel-cobalt-free precursor (Ni 0.90 Mn 0.10 (OH)2), lithium salt, and additive A were weighed in calculated amounts, where lithium salt was LiOH, additive A was ZrO2, LiOH and Ni 0.90 Mn 0.10 (OH)2 in a molar ratio of 1.08:1, and LiOH and Ni 0.90 Mn 0.10The ZrO2 content of the total (OH)2 was 0.5 mol%, and then they were mixed in a high-speed mixer for 20 minutes. The uniformly mixed material was subjected to primary sintering in an oxygen atmosphere, where it was heated from room temperature to 800°C at a rate of 3°C / min and held at that temperature for 10 hours. After primary sintering, the material was cooled, crushed, and pulverized to obtain the pulverized material, which was then washed with pure water at a mass ratio of 1:1 for 15 minutes. It was then sent to a centrifuge for solid-liquid separation for 20 minutes. La2O3 with a particle size range of 10-400 nm and Co2O3 with a particle size range of 20-300 nm were added to the filter cake, where La2O3 accounted for 3 wt% of the filter cake and the molar ratio of La2O3 to Co2O3 was 0.9:1. They were then placed in a tapered screw belt vacuum mixer / dryer for drying, where the drying temperature was 150°C and the drying time was 3 hours, after which the device was rotated. After drying was completed, the dried material was placed in a high-speed mixer and mixed for 15 minutes to achieve uniform mixing. It was then sintered in an oxygen atmosphere, where the temperature was raised from room temperature to 300°C at a rate of 3°C / min and kept at that temperature for 6 hours. Finally, it was naturally cooled to room temperature and sieved, after which the coating layer was found to be La. 0.9 Li 0.3 A sample according to Example 3 was obtained, which is CoO3.

[0039] Example 4 The manufacturing method for high-nickel, cobalt-free cathode materials that can double-reduce residual alkalinity includes the following steps:

[0040] S1: High nickel-cobalt-free precursor (Ni 0.90 Mn 0.10 (OH)2), lithium salt, and additive A were weighed in calculated amounts, where lithium salt was LiOH, additive A was ZrO2, LiOH and Ni 0.90 Mn 0.10 (OH)2 in a molar ratio of 0.95:1, and LiOH and Ni 0.90 Mn 0.10 ZrO2 accounts for 0.1 mol% of the total amount of (OH)2, and then they are added to a high-speed mixer and mixed, and the mixing time is 30 min; S2: The uniformly mixed material was subjected to primary sintering under oxygen atmosphere conditions, where the temperature was increased from room temperature to 800°C at a rate of 3°C / min, and then kept at that temperature for 20 hours after reaching the desired temperature; S3: After the primary sintering, the material is cooled, crushed, and pulverized to obtain the pulverized material, which is then washed with pure water at a mass ratio of 1:1 for 10 minutes, and then sent to a centrifuge for solid-liquid separation for 15 minutes; S4: La2O3 with a particle size range of 10~400nm and Co2O3 with a particle size range of 20~300nm are added to the filter cake, where La2O3 accounts for 0.5wt% of the filter cake and the molar ratio of La2O3 to Co2O3 is 0.5:1. Then, they are put into a tapered screw belt vacuum mixer dryer for the drying process, where the drying temperature is 100℃ and the drying time is 7h. Then, the device is rotated, and after drying, the dried material is put into a high-speed mixer and mixed for 15min to be uniformly mixed; S5: It was sintered under oxygen atmosphere, and the temperature was increased from room temperature to 300°C at a rate of 3°C / min, and kept at that temperature for 15 hours; finally, it was naturally cooled to room temperature, and after sieving, the sample according to Example 4 was obtained.

[0041] Example 5 The manufacturing method for high-nickel, cobalt-free cathode materials that can double-reduce residual alkalinity includes the following steps:

[0042] S1: High nickel-cobalt-free precursor (Ni 0.90 Mn 0.10 (OH)2), lithium salt, and additive A were weighed in calculated amounts, where lithium salt was LiOH, additive A was ZrO2, LiOH and Ni 0.90 Mn 0.10 (OH)2 in a molar ratio of 1.15:1, and LiOH and Ni 0.90 Mn 0.10 ZrO2 accounts for 0.5 mol% of the total amount of (OH)2, and then they are added to a planetary ball mill and mixed, and the mixing time is 5 h; S2: The uniformly mixed material was subjected to primary sintering under oxygen atmosphere conditions, where the temperature was increased from room temperature to 850°C at a rate of 10°C / min, and then kept at 850°C for 3 hours after reaching the desired temperature; S3: After the primary sintering, the material is cooled, crushed, and pulverized to obtain the pulverized material, which is then washed with pure water at a mass ratio of 3:1 for 30 minutes, and then sent to a centrifuge for solid-liquid separation for 30 minutes; S4: La2O3 with a particle size range of 10~400nm and Co2O3 with a particle size range of 20~300nm are added to the filter cake, where La2O3 accounts for 3wt% of the filter cake and the molar ratio of La2O3 to Co2O3 is 0.9:1. Then, they are put into a tapered screw belt vacuum mixer dryer for the drying process, where the drying temperature is 200℃ and the drying time is 0.5h. Then, the device is rotated, and after drying, the dried material is put into a high-speed mixer and mixed for 15min to be uniformly mixed; S5: It was sintered under oxygen atmosphere, and the temperature was increased from room temperature to 450°C at a rate of 7°C / min, and kept at that temperature for 3 hours; finally, it was naturally cooled to room temperature, and after sieving, the sample according to Example 5 was obtained.

[0043] Comparative Example 1 The manufacturing method for high nickel-cobalt-free cathode materials includes the following steps:

[0044] High nickel-cobalt-free precursor (Ni 0.90 Mn 0.10 (OH)2), lithium salt, and additive A were weighed in calculated amounts, where lithium salt was LiOH, additive A was ZrO2, LiOH and Ni 0.90 Mn 0.10 (OH)2 in a molar ratio of 1.03:1, and LiOH and Ni 0.90 Mn 0.10The ZrO2 content of the total (OH)2 was 0.1 mol%, and then the mixture was added to a high-speed mixer and mixed for 15 minutes. The uniformly mixed material was subjected to primary sintering under oxygen atmosphere conditions, where it was heated from room temperature to 800°C at a rate of 3°C / min and held at that temperature for 10 hours. After primary sintering, the material was cooled, crushed, and pulverized to obtain the pulverized material. The pulverized material was washed with pure water at a mass ratio of 1:1 for 15 minutes, and then transferred to a centrifuge for solid-liquid separation for 20 minutes. The filter cake was then directly placed in a tapered screw belt vacuum mixer dryer for the drying process, where it was dried at 150°C for 3 hours and then rotated. WO3 additive was added to the dried material, where WO3 accounted for 1 wt% of the dried material, and then they were put into a high-speed mixer and mixed for 15 minutes to be uniformly mixed. After that, the coated material was sintered in an oxygen atmosphere by increasing the temperature from room temperature to 300°C at a heating rate of 3°C / min and keeping the temperature for 6 hours; finally, it was naturally cooled to room temperature and sieved to obtain a sample according to Comparative Example 1.

[0045] Comparative Example 2 The manufacturing method for high nickel-cobalt-free cathode materials includes the following steps:

[0046] High nickel-cobalt-free precursor (Ni 0.90 Mn 0.10 (OH)2), lithium salt, and additive A were weighed in calculated amounts, where lithium salt was LiOH, additive A was ZrO2, LiOH and Ni 0.90 Mn 0.10 (OH)2 in a molar ratio of 1.03:1, and LiOH and Ni 0.90 Mn 0.10The ZrO2 content of the total (OH)2 was 0.1 mol%, and then the mixture was added to a high-speed mixer and mixed for 15 minutes. The uniformly mixed material was subjected to primary sintering under oxygen atmosphere conditions, where it was heated from room temperature to 800°C at a rate of 3°C / min and held at that temperature for 10 hours. After primary sintering, the material was cooled, crushed, and pulverized to obtain the pulverized material. The pulverized material was washed with pure water at a mass ratio of 1:1 for 15 minutes, and then transferred to a centrifuge for solid-liquid separation for 20 minutes. The filter cake was then directly placed in a tapered screw belt vacuum mixer dryer for the drying process, where it was dried at 150°C for 3 hours and then rotated. La2O3 and Co2O3 were added to the dried material, where La2O3 accounted for 1 wt% of the dried material and the molar ratio of La2O3 to Co2O3 was 0.9:1. They were then put into a high-speed mixer and mixed for 15 minutes to achieve a uniform mixture. The coated material was then sintered in an oxygen atmosphere by increasing the temperature from room temperature to 300°C at a rate of 3°C / min and maintaining the temperature for 6 hours. Finally, it was naturally cooled to room temperature and sieved to obtain a sample according to Comparative Example 2.

[0047] Comparative Example 3 The manufacturing method for high nickel-cobalt-free cathode materials includes the following steps:

[0048] High nickel-cobalt-free precursor (Ni 0.90 Mn 0.10 (OH)2), lithium salt, and additive A were weighed in calculated amounts, where lithium salt was LiOH, additive A was ZrO2, LiOH and Ni 0.90 Mn 0.10 (OH)2 in a molar ratio of 1.03:1, and LiOH and Ni 0.90 Mn 0.10The ZrO2 content was 0.1 mol% of the total (OH)2 content, and then the mixture was added to a high-speed mixer and mixed for 15 minutes. The uniformly mixed material was subjected to primary sintering under oxygen atmosphere conditions, where it was heated from room temperature to 800°C at a rate of 3°C / min and held at that temperature for 10 hours. After primary sintering, the material was cooled, crushed, and pulverized to obtain the pulverized material. The pulverized material was washed with pure water at a mass ratio of 1:1 for 15 minutes, and then transferred to a centrifuge for solid-liquid separation for 20 minutes. WO3 additive was added to the filter cake, where WO3 accounted for 1 wt% of the filter cake. The mixture was then placed in a tapered screw belt vacuum mixer / dryer for drying at 150°C for 3 hours, after which the device was rotated. After drying, the dried material was placed in a high-speed mixer and mixed for 15 minutes to achieve a uniform mixture. It was then sintered in an oxygen atmosphere, where the temperature was raised from room temperature to 300°C at a rate of 3°C / min and maintained at that temperature for 6 hours. Finally, it was naturally cooled to room temperature and sieved to obtain a sample according to Comparative Example 3.

[0049] Comparative Example 4 The manufacturing method for high nickel-cobalt-free cathode materials includes the following steps:

[0050] S1: High nickel-cobalt-free precursor (Ni 0.90 Mn 0.10 (OH)2), lithium salt, and additive A were weighed in calculated amounts, where lithium salt was LiOH, additive A was ZrO2, LiOH and Ni 0.90 Mn 0.10 (OH)2 in a molar ratio of 0.9:1, and LiOH and Ni 0.90 Mn 0.10 ZrO2 accounts for 0.05 mol% of the total amount of (OH)2, and then they are added to a high-speed mixer and mixed, and the mixing time is 5 min; S2: The uniformly mixed material was subjected to primary sintering under oxygen atmosphere conditions, where the temperature was increased from room temperature to 750°C at a rate of 2°C / min, and then kept at 750°C for 22 hours after reaching the desired temperature; S3: After the primary sintering, the material is cooled, crushed, and pulverized to obtain the pulverized material, which is then washed with pure water at a mass ratio of 0.5:1 for 5 minutes, and then sent to a centrifuge for solid-liquid separation for 10 minutes; S4: La2O3 with a particle size range of 10~400nm and Co2O3 with a particle size range of 20~300nm are added to the filter cake, where La2O3 accounts for 0.3wt% of the filter cake and the molar ratio of La2O3 to Co2O3 is 0.4:1. Then, they are put into a tapered screw belt vacuum mixer dryer for the drying process, where the drying temperature is 80℃ and the drying time is 8h. Then, the device is rotated, and after drying, the dried material is put into a high-speed mixer and mixed for 15min to be uniformly mixed; S5: It was sintered in an oxygen atmosphere, and the temperature was increased from room temperature to 250°C at a rate of 2°C / min, and the temperature was maintained for 18 hours; finally, it was naturally cooled to room temperature, and after sieving, a sample according to Comparative Example 4 was obtained.

[0051] Comparative Example 5 The manufacturing method for high nickel-cobalt-free cathode materials includes the following steps:

[0052] S1: High nickel-cobalt-free precursor (Ni 0.90 Mn 0.10 (OH)2), lithium salt, and additive A were weighed in calculated amounts, where lithium salt was LiOH, additive A was ZrO2, LiOH and Ni 0.90 Mn 0.10 (OH)2 in a molar ratio of 1.2:1, and LiOH and Ni 0.90 Mn 0.10 ZrO2 accounts for 0.6 mol% of the total amount of (OH)2, and then they are added to a high-speed mixer and mixed, and the mixing time is 35 min; S2: The uniformly mixed material was subjected to primary sintering under oxygen atmosphere conditions, where the temperature was increased from room temperature to 900°C at a rate of 12°C / min, and then kept at that temperature for 2 hours after reaching the desired temperature; S3: After the primary sintering, the material is cooled, crushed, and pulverized to obtain the pulverized material, which is then washed with pure water at a mass ratio of 4:1 for 35 minutes, and then sent to a centrifuge for solid-liquid separation for 35 minutes; S4: La2O3 with a particle size range of 10~400nm and Co2O3 with a particle size range of 20~300nm are added to the filter cake, where La2O3 accounts for 4wt% of the filter cake and the molar ratio of La2O3 to Co2O3 is 1:1. Then, they are put into a tapered screw belt vacuum mixer dryer for the drying process, where the drying temperature is 220℃ and the drying time is 0.2h. Then, the device is rotated, and after drying, the dried material is put into a high-speed mixer and mixed for 15min to be uniformly mixed; S5: It was sintered in an oxygen atmosphere, and the temperature was increased from room temperature to 500°C at a rate of 8°C / min, and then kept at that temperature for 2 hours; finally, it was naturally cooled to room temperature and sieved to obtain a sample according to Comparative Example 5.

[0053] The positive electrode materials obtained in the above examples and comparative examples were evaluated for their physical indexes and electrical performance under the same conditions.

[0054] 1. The residual alkali content on the surface of the cathode materials obtained in the examples and comparative examples was measured.

[0055] The measurement process is as follows: weigh a predetermined amount of sample, add a predetermined amount of deionized water, stir for a predetermined time, filter, and directly titrate with hydrochloric acid standard titration solution. When the color of the indicator changes, it indicates that the acid and alkali have been completely neutralized; record the volume of the acid solution used in the titration, and calculate the residual alkali content in the sample according to the chemical equation of acid-alkali reaction.

[0056] The results of residual alkali content measurements are shown in Table 1. The data clearly show that the residual alkali content on the surface of the samples according to the Examples is significantly lower than that of the Comparative Examples. Furthermore, analysis of the data revealed that the sample according to Comparative Example 1, in which other additives were added to the dried material, had the highest residual alkali content. The samples according to Comparative Examples 2 and 3, in which other additives were added to the filter cake and the La source and Co source were added to the dried material, had slightly lower residual alkali content compared to the sample according to Comparative Example 1, but the effect was not significant. In contrast, the above Examples of the present application achieved a significant reduction in residual alkali content. Therefore, the method for reducing the surface residual alkali content according to the above Examples of the present application is highly effective. As can be seen from this, the cathode material obtained using the method for reducing residual alkali through dual modification according to the above Examples of the present application not only achieved a primary reduction in residual alkali during washing, but also consumed residual alkali on the material surface during the subsequent process due to the addition of additives to the filter cake and the formation of an LLCO coating layer, which resulted in a secondary reduction in residual alkali.

[0057] [Table 1] 2. The electrical performance of the button-type half cells was measured for the cathode materials obtained in the examples and comparative examples.

[0058] The measurement process was as follows: In an argon-filled glove box, a button cell battery was assembled using a lithium metal strip for the negative electrode. The positive electrode sheet consisted of 92 wt% active material, 4 wt% Super-P (i.e., superconducting carbon black) conductive material, and 4 wt% PVDF (polyvinylidene fluoride) adhesive. The measurement phase for measuring the charge / discharge cycles was as follows: the voltage range was 3.0 to 4.4 V, and the cycles were cycled three times at cycle rates of 0.2 C, 0.5 C, 1 C, 2 C, 3 C, and 0.2 C; then, the cycle was repeated 50 times at a cycle rate of 1 C.

[0059] Figure 3 shows a comparison of the initial charge / discharge curves of the button-type half-cells fabricated from the cathode materials obtained in Examples 1 and 2 and Comparative Examples 2 and 3. As can be seen from Figure 3, the initial charge specific capacity of the corresponding button-type half-cells was as follows: Sample 2 > Sample 1 > Sample 3 > Sample 2; the initial discharge specific capacity of the corresponding button-type half-cells was as follows: Sample 2 > Sample 1 > Sample 2 > Sample 3; and the initial efficiency of the corresponding button-type half-cells was as follows: Sample 2 > Sample 1 > Sample 2 > Sample 3; and the comparison revealed that the button-type half-cells fabricated from the cathode materials obtained using the method of reducing residual alkali by dual modification according to the above examples of the present application had improved initial charge specific capacity, initial discharge specific capacity, and initial efficiency compared to the comparative examples.

[0060] Figure 4 shows a comparison of the capacity retention of the corresponding button-type half-cells fabricated from the cathode materials obtained in Examples 1-3 and Comparative Examples 1-3 after 50 charge-discharge cycles under the same measurement conditions. As can be seen from Figure 4, the capacity retention of the samples from Examples 1, 2, and 3 is superior to that of the samples from Comparative Examples 1, 2, and 3. Also referring to the FESEM image in Figure 1, the sample from Example 2 in Figure 1 exhibits a uniform coating layer on the material surface. Furthermore, the surface coating exhibits good dispersibility, a relatively uniform coating, and no aggregation. Furthermore, the sample from Example 2 was subjected to EDS analysis using the XRD pattern of LLCO produced in Figure 2. The results are shown in Table 2. The measured coating layer contained La, Li, and Co elements, indicating the formation of a perovskite coating layer. The results of the electrical performance measurements also indicate that the positive electrode material according to the present invention is coated with perovskite, and the LLCO coating layer formed in situ on the surface effectively improves the ionic conductivity of the positive electrode material, improves the lithium ion embedding / extraction efficiency, effectively prevents direct contact between the electrolyte and the positive electrode material, reduces the dissolution of metal ions, and further improves the discharge capacity, charge / discharge efficiency, and cycling performance of the material. This clearly shows that the positive electrode material obtained using the method for reducing residual alkali through dual modification according to the present invention significantly improved the cycling performance of the positive electrode material compared to the comparative example after the formation of the perovskite coating layer due to the high lithium ion conductivity of the LLCO material.

[0061] [Table 2] Figure 5 shows a comparison of the capacity retention rates at different magnifications for the corresponding button-type half cells fabricated from the positive electrode materials obtained in Examples 1 to 3 and Comparative Examples 1 to 3. As can be seen from Figure 5, the discharge capacity and capacity retention rates at different magnifications for the positive electrode material fabricated in Comparative Example 2 are significantly lower than those for the positive electrode material with an LLCO coating layer fabricated in Example 2. The magnification performance of the positive electrode material fabricated in Example 2 is significantly superior, especially at high magnifications. This is because adding the La source and Co source to the filter cake is more advantageous for achieving capacity and magnification performance than adding the La source and Co source to the dried material. Furthermore, the discharge capacity and capacity retention rates at different magnifications for the positive electrode material fabricated in Comparative Example 3 are significantly lower than those for the positive electrode material with an LLCO coating layer fabricated in Example 2. The magnification performance of the positive electrode material fabricated in Example 2 is significantly superior, especially at high magnifications. This is because the LLCO coating layer formed from the positive electrode material coated with the La source and Co source is a fast ion conductor, thereby reducing the resistance of the positive electrode material and improving capacity and magnification performance.

[0062] As can be seen from the above, compared to the comparative examples, in each example of the present application, the material surface is coated with a La source and a Co source, and then sintered to form a perovskite coating layer in situ on the material surface. This allows for a primary reduction in residual alkalinity through water washing. Furthermore, the perovskite coating layer reacts with the residual lithium in the material, reducing the residual lithium content on the surface of the high-nickel material, thereby achieving a secondary reduction in residual alkalinity. Due to the formation of the perovskite coating layer, this positive electrode material exhibits high lithium-ion conductivity, good capacity retention and rechargeability, and high reversibility. The produced high-nickel, cobalt-free positive electrode material exhibits low residual alkalinity, high discharge capacity, good rechargeability, and excellent battery cycling performance. It was also found that the overall performance of the material is improved when all process parameters are within the preferred ranges of the present application.

[0063] The above is merely a preferred embodiment of the present application, and does not limit the present application. Those skilled in the art can make various modifications and changes to the present application. Any amendments, equivalent replacements, improvements, etc. made without departing from the spirit and principle of the present application shall fall within the protection scope of the present application.

Claims

1. A method for producing a high-nickel / cobalt-free positive electrode material capable of doubly reducing residual alkali, comprising the following steps: S1: A high-nickel, cobalt-free precursor is thoroughly mixed with a lithium salt and a dopant A to obtain a mixture B; the general formula of the high-nickel, cobalt-free precursor is Ni ｙ Mn １-ｙ (OH) ２ and 0.75<y≦0.95 is satisfied, and the Li element and Ni in the lithium salt ｙ Mn １-ｙ (OH) ２ The molar ratio of the lithium salt to Ni is (0.95 to 1.15):

1. ｙ Mn １-ｙ (OH) ２ and the dopant A is a compound containing at least one selected from Al, Zr, W, Mo, and Nb; S2: The mixture B is subjected to primary sintering, cooling, and crushing in an oxygen atmosphere according to a first temperature curve to obtain a high-nickel and cobalt-free positive electrode material C. The first temperature curve refers to first increasing the temperature to 800-850°C at a rate of 3-10°C / min in an oxygen atmosphere, and then maintaining the temperature for 3-20 hours after reaching the desired temperature. S3: The high nickel and cobalt-free positive electrode material C was washed with water and subjected to solid-liquid separation to obtain a filter cake; S4: Adding the La source and the Co source to the filter cake, then putting them together into a drying device and drying them under rotation, and after drying is completed, putting the dried material into a mixing device and mixing uniformly to obtain a high-nickel and cobalt-free positive electrode material D, in which the La source accounts for 0.5 to 3 wt % of the filter cake, and the molar ratio of the La element in the La source to the Co element in the Co source is 0.5 to 0.9:1; S5: The high nickel and cobalt-free positive electrode material D is subjected to secondary sintering according to the second temperature curve in an oxygen atmosphere, cooled, and sieved to obtain a positive electrode material having a chemical formula of Li ｘ Ni ｙ Mn １-ｙ A ｚ O ２ And the surface is La ａ Li ｂ CoO ３ A perovskite-coated high-nickel, cobalt-free cathode material is obtained, and satisfies the conditions 0.75<y≦0.95, 0.95≦x≦1.15, and 0.001<z≦0.

005. The second temperature curve refers to first increasing the temperature to 300-450°C at a rate of 3-7°C / min in an oxygen atmosphere, and then maintaining the temperature for 3-15 hours after reaching the desired temperature.

2. 2. The method for producing a high nickel-cobalt-free positive electrode material capable of doubly reducing residual alkali as claimed in claim 1, wherein the lithium salt in S1 is LiOH.

3. 3. The method for producing a high-nickel-cobalt-free positive electrode material capable of doubly reducing residual alkali according to claim 1 or 2, wherein in the washing step in S3, the mass ratio of water to the high-nickel-cobalt-free positive electrode material C is 1 to 3:1, the washing time is 10 to 30 minutes, and then the material is sent to a solid-liquid separator for solid-liquid separation, for a time of 15 to 30 minutes.

4. In S4, the La source is La ２ O ３ , La(NO ３ ) ３ , La ２ (CO ３ ) 8H ２ and the Co source is Co. ２ O ３ , Co(OH) ２ , Co(NO ３ ) ２ , CoCO ３ , Co ３ O ４ 4. The method for producing a high-nickel / cobalt-free positive electrode material capable of doubly reducing residual alkali according to claim 1, wherein the La source has a particle size range of 10 to 400 nm and the Co source has a particle size range of 20 to 300 nm.

5. 5. The method for producing a high-nickel and cobalt-free positive electrode material capable of doubly reducing residual alkali according to claim 1, wherein in S4, the drying temperature is 100 to 200°C and the drying time is 0.5 to 7 hours.

6. 6. The method for producing a high-nickel-cobalt-free positive electrode material capable of doubly reducing residual alkali according to any one of claims 1 to 5, wherein in step S1, a high-speed mixer or a planetary ball mill is used to mix the high-nickel-cobalt-free precursor, the lithium salt, and the dopant A, and the mixing time in the high-speed mixer is 10 to 30 minutes, and the mixing time in the planetary ball mill is 3 to 5 hours.

7. In S1, the Li element and Ni in the lithium salt ｙ Mn １-ｙ (OH) ２ The method for producing a high-nickel / cobalt-free positive electrode material capable of doubly reducing residual alkali according to any one of claims 1 to 6, characterized in that the molar ratio of

8. 8. The method for producing a high-nickel and cobalt-free positive electrode material capable of doubly reducing residual alkali according to any one of claims 1 to 7, characterized in that in S2, the first temperature curve is to first raise the temperature to 800 to 820°C at a heating rate of 3 to 5°C / min in an oxygen atmosphere, and then, once the desired temperature is reached, to keep the temperature for 10 to 20 hours.

9. 9. The method for producing a high-nickel and cobalt-free positive electrode material capable of doubly reducing residual alkali according to any one of claims 1 to 8, wherein in step S5, the second temperature curve is such that the temperature is first raised to 300 to 350°C at a heating rate of 3 to 6°C / min in an oxygen atmosphere, and once the desired temperature is reached, the temperature is maintained for 6 to 15 hours.

10. A high nickel-cobalt-free positive electrode material capable of doubly reducing residual alkalinity according to any one of claims 1 to 9, which is obtained by the method for producing the high nickel-cobalt-free positive electrode material, and has the chemical formula Li ｘ Ni ｙ Mn １-ｙ A ｚ O ２ And the surface is La ａ Li ｂ CoO ３ A high-nickel, cobalt-free positive electrode material coated with perovskite, characterized in that the following conditions are satisfied: 0.75<y≦0.95, 0.95≦x≦1.15, 0.001<z≦0.005, 0.5≦a≦0.9, and 0.3≦b≦1.5.

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