A lithium-rich cobalt-doped lithium ion battery cathode material and a preparation method thereof

Abstract

The application relates to the technical field of lithium ion batteries, and discloses a lithium-rich cobalt-doped lithium ion battery positive electrode material and a preparation method thereof. The lithium-rich cobalt-doped lithium ion battery positive electrode material is composed of a nickel-manganese hydroxide precursor Ni 0.5 Mn 0.5 (OH)2, a cobalt hydroxide precursor Co(OH)2 and a lithium source, and the positive electrode material can be prepared through a mixing ball milling, low-temperature sintering and grinding procedure. The lithium-rich cobalt-doped lithium ion battery positive electrode material can obviously improve the cycle performance and rate performance of a lithium ion battery under a high voltage between 3.0 and 4.5 V, optimizes the thermal stability of the positive electrode material itself, effectively improves the reversible capacity of the positive electrode material, reduces the manufacturing cost, improves the electrochemical performance and improves the safety performance of the battery.

Description

Technical Field

[0001] This invention relates to the field of lithium-ion battery technology, and in particular to a lithium-rich cobalt-doped lithium-ion battery cathode material and its preparation method. Background Technology

[0002] With the deepening research on lithium-ion cathode materials, many methods have been proposed to meet the market's demand for high energy density in lithium nickel cobalt manganese oxide (NCM) materials. These include: improving the kinetic properties of materials by introducing new elements through doping or coating; increasing battery capacity by changing the original metal elements; and optimizing the morphology and structure of materials to improve energy density. Previous research on the comprehensive performance and structural evolution of NCM materials with different transition metal ratios shows that LiNi... 0.5 Co 0.2 Mn 0.3 O2 (NCM523) exhibits superior overall performance. Its 50% nickel content gives it good reversible capacity during cycling, and due to its relatively low nickel content, it also has excellent cycle stability and thermal safety performance. It is the most commercially valuable and promising alternative to lithium iron phosphate in the NCM system.

[0003] Nevertheless, high costs and raw material supply chain shortages have forced researchers to find ways to eliminate or replace 20% of the cobalt in NMC523 to achieve similar battery performance. Theoretical calculations show that when Co in NMC523 is replaced with Mn, the resulting layered oxide LiNi... 0.5 Mn 0.5 O2 still possesses a theoretical capacity of 280 mAh / g, confirming the LiNi... 0.5 Mn 0.5 The feasibility of O2 as a substitute for LiCoO2. However, LiNi 0.5 Mn 0.5O2 fails to reach its theoretical capacity because the presence of manganese ions promotes the mixing of Li / Ni cations, hindering the diffusion of lithium ions within the layered structure. To address this challenge, Chinese patent CN111162322A enhances the lithium storage performance and improves the cycle and rate performance of nickel-manganese oxide by constructing a porous nanosheet structure. Chinese patent CN107591519A achieves stable structure in conventional lithium nickel-cobalt-manganese cathode materials even under repeated high-current charge-discharge cycles by doping grain boundaries. Chinese patent CN201510026729 uses ultrasonic chemical nickel plating to uniformly coat and modify the surface of lithium nickel manganese oxide materials. The resulting nickel coating, as an excellent conductor, significantly improves the conductivity of the material after coating, thus enhancing its rate and cycle performance. Although similar control methods can effectively improve the structural stability and cycle performance of nickel-manganese oxide lithium-ion batteries, they still fall far short of practical application requirements due to their complex processes and high costs. Current cathode materials struggle to balance manufacturing costs, capacity, internal resistance, and other electrochemical properties with their own safety.

[0004] Existing ternary cathode materials suffer from the following problems: structural reconstruction, particle breakage, transition metal ion dissolution, and damage to the cathode-electrolyte interface film easily occur during long-term cycling. Oxide cathodes in a highly delithiated state exhibit extremely poor thermal stability, readily decomposing at high temperatures to generate oxygen, leading to severe oxidation of the electrolyte on the cathode surface, releasing large amounts of heat and producing significant gas emissions. In severe cases, this can induce serious fires and explosions in the battery. Therefore, it is necessary to develop a lithium-ion battery cathode material that is structurally stable, has excellent performance, and is highly safe. Summary of the Invention

[0005] The technical problem this invention aims to solve is to overcome the shortcomings of existing technologies and provide a lithium-rich cobalt-doped lithium-ion battery cathode material and its preparation method. The lithium-rich cobalt-doped lithium-ion battery cathode material of this invention exhibits stable structure, excellent performance, and high safety. It controls the manufacturing cost of the cathode material, improves the crystal structure stability under high voltage, suppresses interfacial side reactions, enhances its thermal safety, and reduces the possibility of thermal runaway, thereby improving the cycle stability, rate performance, and safety characteristics of the lithium-ion battery.

[0006] The technical solution adopted by this invention to solve its technical problem is:

[0007] A lithium-rich cobalt-doped lithium-ion battery cathode material, consisting of a nickel-manganese hydroxide precursor Ni 0.5 Mn 0.5 The mixture was obtained by sintering cobalt hydroxide precursor Co(OH)2 and lithium source; wherein the nickel-manganese hydroxide precursor Ni 0.5 Mn0.5 The weight parts of (OH)2 are 60-75 parts, the weight parts of the cobalt hydroxide precursor Co(OH)2 are 0-5 parts, and the weight parts of the lithium source are 25-35 parts.

[0008] Furthermore, the lithium source is LiOH·H2O or Li2CO3.

[0009] Furthermore, the sintering method is a tube furnace with an oxygen atmosphere or a muffle furnace with an air atmosphere.

[0010] Furthermore, the nickel-manganese hydroxide precursor Ni 0.5 Mn 0.5 (OH)2 particles are available in sizes of 25μm, 50μm, 100μm, 200μm, and 400μm.

[0011] Furthermore, the cobalt hydroxide precursor Co(OH)2 has a particle size of 25μm, 50μm, 100μm, 200μm, or 400μm.

[0012] A method for preparing the lithium-rich cobalt-doped lithium-ion battery cathode material as described above specifically includes the following steps:

[0013] Step S1: Weigh the nickel-manganese hydroxide precursor Ni. 0.5 Mn 0.5 (OH)2, cobalt hydroxide precursor Co(OH)2 and lithium source;

[0014] Step S2: The nickel-manganese hydroxide precursor Ni... 0.5 Mn 0.5 After a simple mixture of (OH)2 and the cobalt hydroxide precursor Co(OH)2, the mixture is placed in a mechanical mixing device and mixed for 1 hour. After thorough mixing, the precursor material is obtained.

[0015] Step S3: Place the precursor material and lithium source into a mortar and grind for 10 minutes to obtain a mixed powder;

[0016] Step S4: Place the mixed powder into the sample cell, then place it in the sintering furnace and sinter for 20 hours to obtain the initial product;

[0017] Step S5: Place the initial product into a mortar and grind for 2 minutes to obtain the finished lithium-rich cobalt-doped lithium-ion battery cathode material.

[0018] Furthermore, in step S4, the sintering temperature is 400°C.

[0019] The beneficial effects of this invention are as follows: This invention has a reasonable design and a simple preparation method, and has the following advantages:

[0020] (1) The lithium-rich cobalt-doped lithium-ion battery cathode material of the present invention can significantly improve the cycle performance of nickel manganese oxide lithium-ion batteries at high voltages of 3.0 to 4.5V. Compared with existing cathode materials, the specific capacity of the battery increases to 180.00 mA / g and the capacity retention rate increases to 98%.

[0021] (2) The lithium-rich cobalt-doped lithium-ion battery cathode material of the present invention can improve the thermal stability of the cathode material itself, increase the thermal decomposition reaction temperature of the cathode material, and achieve the purpose of delaying the thermal runaway rate of the battery and improving the safety performance of the battery.

[0022] (3) The lithium-rich cobalt-doped lithium-ion battery cathode material of the present invention can significantly improve the rate performance of the material. When discharged at high rate, the capacity of the lithium-rich material is more than three times that of the existing cathode material. Attached Figure Description

[0023] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0024] Figure 1 This is a comparison chart of the rate performance and cycle efficiency curves of the half-cells assembled in Example 2, Comparative Example 1, and Comparative Example 2 of this invention.

[0025] Figure 2 This is a comparison diagram of the lithium-ion diffusion coefficients of the half-cells assembled in Example 2 and Comparative Example 1 of this invention.

[0026] Figure 3 The graphs show the cyclic stability of Embodiment 3 and Comparative Example 1 in this invention.

[0027] Figure 4 This is a comparison chart of the thermogravimetric (TG) analysis curves of the cathode materials in Example 2, Comparative Example 1, and Comparative Example 3 of this invention;

[0028] Figure 5 This is a comparison chart of the thermal analysis DSC curves of the cathode materials in Examples 1, 2, and 3 of this invention and Comparative Example 1. Detailed Implementation

[0029] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0030] It should be noted that the terminology used herein is for the purpose of describing particular implementations only and is not intended to limit the exemplary implementations according to this application. As used herein, the singular form includes the plural form unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this description, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0031] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] A lithium-rich cobalt-doped lithium-ion battery cathode material, consisting of a nickel-manganese hydroxide precursor Ni 0.5 Mn 0.5 The mixture was obtained by sintering cobalt hydroxide precursor Co(OH)2 and lithium source; wherein the nickel-manganese hydroxide precursor Ni 0.5 Mn 0.5 The weight parts of (OH)2 are 60-75 parts, the weight parts of the cobalt hydroxide precursor Co(OH)2 are 0-5 parts, and the weight parts of the lithium source are 25-35 parts.

[0033] The lithium source is LiOH·H2O or Li2CO3; the sintering method is a tube furnace with an oxygen atmosphere or a muffle furnace with an air atmosphere.

[0034] Ni hydroxide precursor 0.5 Mn 0.5 One type of (OH)2 with particle sizes of 25μm, 50μm, 100μm, 200μm, and 400μm; and one type of cobalt hydroxide precursor Co(OH)2 with particle sizes of 25μm, 50μm, 100μm, 200μm, and 400μm.

[0035] A method for preparing the lithium-rich cobalt-doped lithium-ion battery cathode material as described above specifically includes the following steps:

[0036] Step S1: Weigh the nickel-manganese hydroxide precursor Ni. 0.5 Mn 0.5 (OH)2, cobalt hydroxide precursor Co(OH)2 and lithium source;

[0037] Step S2: The nickel-manganese hydroxide precursor Ni... 0.5 Mn 0.5 After a simple mixture of (OH)2 and the cobalt hydroxide precursor Co(OH)2, the mixture is placed in a mechanical mixing device and mixed for 1 hour. After thorough mixing, the precursor material is obtained.

[0038] Step S3: Place the precursor material and lithium source into a mortar and grind for 10 minutes to obtain a mixed powder;

[0039] Step S4: Place the mixed powder into the sample cell, then place it in the sintering furnace and sinter for 20 hours at a sintering temperature of 400℃ to obtain the initial product;

[0040] Step S5: Place the initial product into a mortar and grind for 2 minutes to obtain the finished lithium-rich cobalt-doped lithium-ion battery cathode material.

[0041] Example 1

[0042] A method for preparing a lithium-rich cobalt-doped lithium-ion battery cathode material specifically includes the following steps:

[0043] Step S1: Weigh the nickel-manganese hydroxide precursor Ni. 0.5 Mn 0.5 The mixture contains 60 parts of cobalt hydroxide precursor Co(OH)₂, 5 parts of cobalt hydroxide precursor Co(OH)₂, and 35 parts of lithium source Li₂CO₃. Among these, the nickel-manganese hydroxide precursor Ni… 0.5 Mn 0.5 The particle sizes of (OH)2 and the cobalt hydroxide precursor Co(OH)2 are 25 μm, respectively;

[0044] Step S2: The nickel-manganese hydroxide precursor Ni... 0.5 Mn 0.5 After a simple mixture of (OH)2 and the cobalt hydroxide precursor Co(OH)2, the mixture is placed in a mechanical mixing device and mixed for 1 hour. After thorough mixing, the precursor material is obtained.

[0045] Step S3: Place the precursor material and lithium source into a mortar and grind for 10 minutes to obtain a mixed powder;

[0046] Step S4: Place the mixed powder into the sample cell, and then place it in a tube furnace under an oxygen atmosphere for sintering for 20 hours at a sintering temperature of 400℃ to obtain the initial product.

[0047] Step S5: Place the initial product into a mortar and grind for 2 minutes to obtain the finished lithium-rich cobalt-doped lithium-ion battery cathode material.

[0048] The manufacturing process of a positive electrode sheet is as follows: lithium-rich cobalt-doped lithium-ion battery positive electrode material, conductive agent acetylene black, and binder polyvinylidene fluoride (PVDF) are mixed in a mass ratio of positive electrode material: acetylene black: PVDF = 8:1:1. After mixing, N-methylpyrrolidone (NMP) is added and stirred thoroughly to form a uniform positive electrode slurry. This slurry is then uniformly coated onto a 15μm thick aluminum foil and dried in a forced-air drying oven at 120℃ for 12 hours to obtain the positive electrode sheet for later use.

[0049] The manufacturing process of a positive electrode half-cell is as follows: the above positive electrode sheet is used as the positive electrode, the lithium metal sheet is used as the negative electrode, Celgard 2500 is used as the separator, electrolyte is added, and the cells are assembled into a button cell with battery model CR2032 in a glove box.

[0050] The battery cycle test procedure is as follows:

[0051] The assembled button cell was left to stand at room temperature (25°C) for 12 hours, and then cycled at a charge / discharge voltage of 3.0–4.5V. The battery was first charged and discharged for three cycles at a current of C / 20, and then 50–100 cycles were performed at a current of C / 5.

[0052] The test procedure is as follows: constant current charging at C / 20 to 4.5V, followed by discharge at C / 20 to 3.0V. After fully activating the electrode material, the battery is evaluated for cycle stability by 100 charge-discharge cycles at C / 5. After every 50 cycles, the battery is checked by cycling at C / 20.

[0053] The battery rate performance test steps are as follows:

[0054] The assembled button cell was left to stand at room temperature (25°C) for 12 hours, and then subjected to cycle and rate tests with a charge / discharge voltage of 3.0–4.5V. The battery was first charged and discharged twice at a current of C / 20, then charged at a current of C / 20, and then discharged sequentially at five different increasing rates.

[0055] The test procedure is as follows: constant current charging at C / 20 to 4.5V, followed by discharge at C / 20 to 3.0V. After fully activating the electrode material, the battery is charged at a current of C / 20, and then discharged sequentially at increasing rates of C / 20, C / 5, C / 2, 1C, and 2C to obtain the reversible capacity of the battery at different rates, thereby evaluating the rate performance of the battery.

[0056] The thermogravimetric analysis (TGA) process is as follows:

[0057] After cycling, the battery was disassembled in a glove box, the positive electrode was separated, and the positive electrode was cleaned with dimethyl carbonate solvent to remove residual electrolyte and allowed to dry. The electrode material was scraped off the aluminum sheet, and 5 mg of the electrode was weighed and placed in a sample cell. A thermogravimetric analysis (TGA) was performed on the positive electrode material at a heating rate of 10.0 °C to 550 °C and a heating range of 10.0 °C / min. The mass change curve of the positive electrode material during the heating process was recorded. For comparison, TG experiments were performed separately on different positive electrode material samples.

[0058] The thermal analysis test process is as follows:

[0059] The cathode material was obtained using the same pretreatment method as for TG testing. 8 mg of the electrode was weighed and placed in the sample cell. Differential scanning calorimetry (DSC) experiments were performed on a thermal analyzer with a heating range of 100–800 °C and a heating rate of 10.0 °C / min. The heat generation curve of the cathode material during the heating process was recorded. For comparison, DSC experiments were also performed individually on different cathode material samples.

[0060] Example 2

[0061] The difference from Example 1 is that the lithium-rich cobalt-doped lithium-ion battery cathode material in this example is composed of the nickel-manganese hydroxide precursor Ni. 0.5 Mn 0.5 The mixture was obtained by sintering (OH)₂ and a lithium source. The nickel-manganese hydroxide precursor Ni... 0.5 Mn 0.5 The weight parts of (OH)2 are 65 parts, the particle size is 25 μm, and the weight parts of lithium source Li2CO3 are 35 parts.

[0062] The cathode material and cathode half-cell were prepared using the same method as in Example 1, and their cycle performance, rate performance, ion diffusion coefficient and thermal stability were tested.

[0063] The lithium-ion diffusion coefficient test procedure is as follows:

[0064] The Atlung method with intermittent diffusion (AMID) was employed. Testing was conducted in the first cycle using a voltage window of 3.0–4.5 V, followed by charging to 4.5 V at C / 40. Subsequent discharges were performed at consecutive rates of 5C, 3C, 2C, 1C, C / 2.5, C / 5, C / 10, C / 20, C / 40, C / 80, and C / 160, with a 1-hour open voltage (OCV) between each C rate. The initial interval was 4.5–4.3 V, followed by seven voltage intervals from 4.3 V to 3.6 V in 0.1 V increments, and a single interval from 3.6 V to 3.0 V. The lithium-ion diffusion coefficient within each voltage interval was calculated.

[0065] Example 3

[0066] The difference from Example 1 is that in the lithium-rich cobalt-doped lithium-ion battery cathode material of this example, the nickel-manganese hydroxide precursor Ni... 0.5 Mn 0.5 The composition comprises 75 parts by weight of cobalt hydroxide precursor Co(OH)2, 2 parts by weight of cobalt hydroxide precursor Co(OH)2, and 25 parts by weight of lithium source Li2CO3. The nickel-manganese hydroxide precursor Ni... 0.5 Mn 0.5 The particle size of (OH)2 is 400 μm, and the particle size of the cobalt hydroxide precursor Co(OH)2 is 200 μm.

[0067] The cathode material and coin cell were prepared using the same method as in Example 1, and their cycle performance and thermal stability were tested.

[0068] Comparative Example 1

[0069] The difference from Example 1 is that in the positive electrode material of this comparative example, the nickel-manganese hydroxide precursor Ni... 0.5 Mn 0.5 The weight parts of (OH)2 are 75 parts, and the weight parts of the lithium source Li2CO3 are 25 parts. Among them, the nickel-manganese hydroxide precursor Ni... 0.5 Mn 0.5 The particle size of (OH)2 is 400 μm; the particle size of the cobalt hydroxide precursor Co(OH)2 is 200 μm.

[0070] The cathode material and cathode half-cell were prepared using the same method as in Example 1, and their cycle performance, rate performance, ion diffusion coefficient and thermal stability were tested.

[0071] Comparative Example 2

[0072] The difference from Example 1 is that in the positive electrode material of this comparative example, the nickel-manganese hydroxide precursor Ni... 0.5 Mn 0.5 The weight of (OH)2 is 70 parts, the particle size is 100μm, and the weight of lithium source Li2CO3 is 30 parts.

[0073] The positive electrode material and positive electrode half-cell were prepared using the same method as in Example 1, and their cycle performance and rate performance were tested.

[0074] Comparative Example 3

[0075] The difference from Example 1 is that the cathode material of this comparative example is a ternary cathode material in the prior art.

[0076] The positive electrode material and positive electrode half-cell were prepared using the same method as in Example 1, and thermal stability tests were performed.

[0077] from Figure 1As can be seen, compared with Example 2, Comparative Example 1, and Comparative Example 2, increasing the weight of the lithium source from 25 parts to 35 parts significantly improved the rate performance of the battery and significantly increased the discharge capacity. At a 2C current rate, the capacity increased from 40 mAh / g in Comparative Example 1 to 140 mAh / g in Example 2, and Example 2 was less affected by the current rate. Furthermore, the cycling performance results of the three cathode half-cells showed that the reversible capacity of the three cathode materials also exhibited a gradient increasing trend. After long-cycle cycling, the capacities of Comparative Example 1, Comparative Example 2, and Example 2 decreased by 16%, 19%, and 6%, respectively. Therefore, Example 2 has a significant advantage in terms of cycle stability.

[0078] from Figure 2 The lithium-ion diffusion coefficient results show that the ion diffusion capability of Example 2 is improved by nearly two orders of magnitude compared to Comparative Example 1, indicating that lithium ions in the material can migrate rapidly within the structure, fully reflecting... Figure 1 The reason for the optimized performance at medium rate is that the lithium-rich cobalt-doped lithium-ion battery cathode material of this invention can significantly improve electrochemical performance by enhancing lithium-ion diffusion kinetics.

[0079] Figure 3 Example 3, doped with cobalt, was compared with Comparative Example 1, which did not contain cobalt, under the same voltage range and current rate. It was found that Example 3, compared to Comparative Example 1, exhibited a further reduction in cycle capacity loss, retaining over 98% of its capacity after 100 cycles. This indicates that the cobalt doping in Example 3 effectively stabilizes the internal structure of the cathode material, ensuring its stability during long-term charge-discharge cycles and effectively extending battery life.

[0080] In terms of thermal safety performance, whether Figure 4 The TG test results are still Figure 5 The DSC test results in Example 1 show that the lithium-rich cobalt-doped cathode material exhibits good thermal stability. Figure 4 In the thermogravimetric curve comparison chart, Comparative Example 3 exhibits a mass loss approximately tens of times greater than that of Example 2 within the same temperature range. Furthermore, the onset temperature of its mass loss is nearly 100°C lower than that of Example 2, demonstrating extremely strong structural instability, which is highly detrimental to maintaining the overall safety of the battery. In addition, in Figure 5In the comparison of heat generation rates, Example 3, doped with cobalt, showed a significantly lower heat generation rate and a corresponding substantial reduction in heat generation compared to Comparative Example 1. The addition of excess lithium also had a similar effect compared to Comparative Example 2. However, considering the synergistic effect of excess lithium and cobalt doping, Example 1 exhibited the lowest heat generation rate and heat generation. Therefore, lithium-rich cobalt-doped cathode materials can maximize material stability, thereby reducing the heat generation of the cathode material and effectively suppressing the initiation reaction of battery thermal runaway.

[0081] In summary, the lithium-rich cobalt-doped nickel-manganese oxide cathode material of the present invention not only enhances the lithium-ion diffusion capacity within the cathode structure but also suppresses undesirable structural transformations. The synergistic effect of excess lithium and trace cobalt doping forms a high-quality, stable symbiotic crystal structure within the material, protecting the structural integrity of the electrode material while suppressing side reactions and improving the battery's cycle performance and rate performance under high voltage. This achieves a lithium-ion battery with excellent high-voltage electrochemical performance while maintaining good safety performance.

[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A lithium-rich cobalt-doped lithium-ion battery cathode material, characterized in that: The lithium-rich cobalt-doped lithium ion battery positive electrode material is prepared by composite sintering of a nickel-manganese hydroxide precursor Ni 0.5 Mn 0.5 (OH)2, a cobalt hydroxide precursor Co(OH)2, and a lithium source; wherein the weight parts of the nickel-manganese hydroxide precursor Ni 0.5 Mn 0.5 (OH)2 are 60-75 parts, the weight parts of the cobalt hydroxide precursor Co(OH)2 are 0-5 parts, and the weight parts of the lithium source are 25-35 parts. 2.The Li-rich Co-doped cathode material of lithium ion battery of claim 1, characterized in that: The lithium source is LiOH·H2O or Li2CO3. 3.The Li-rich Co-doped cathode material of lithium ion battery of claim 1, characterized in that: The sintering mode is a tube furnace in oxygen atmosphere or a muffle furnace in air atmosphere. 4.The Li-rich Co-doped cathode material of lithium ion battery of claim 1, characterized in that: The nickel-manganese hydroxide precursor Ni 0.5 Mn 0.5 (OH)2particle size of 25 μm, 50 μm, 100 μm, 200 μm, 400 μm.

5. The lithium-rich cobalt-doped lithium-ion battery cathode material of claim 1, wherein: The cobalt hydroxide precursor Co(OH)2 has a particle size of 25 μm, 50 μm, 100 μm, 200 μm or 400 μm.

6. A method for preparing a lithium-rich cobalt-doped lithium-ion battery cathode material according to any one of claims 1 to 5, characterized in that: Specifically comprising the following steps: Step S1, weigh nickel-manganese hydroxide precursor Ni 0.5 Mn 0.5 (OH)2, cobalt hydroxide precursor Co(OH)2, and lithium source; Step S2, the nickel-manganese hydroxide precursor Ni 0.5 Mn 0.5 After simple mixing of the nickel-manganese hydroxide precursor Ni (OH)2and the cobalt hydroxide precursor Co(OH)2, the mixture is put into a mechanical mixing device, and the mixing time is 1 h. After sufficient mixing, the precursor material is obtained. Step S3, putting the precursor material and the lithium source into a mortar and grinding for 10 min to obtain a mixed powder; Step S4, putting the mixed powder into a sample cell and then into a sintering furnace and sintering for 20 h to obtain a primary product; Step S5, putting the primary product into a mortar and grinding for 2 min to obtain a finished product of the lithium-rich cobalt-doped lithium ion battery cathode material.

7. The preparation method of the lithium-rich cobalt-doped lithium-ion battery cathode material according to claim 6, characterized in that: In the step S4, the sintering temperature is 400 ℃.

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