Long-cycle high-capacity retention rate lithium-rich manganese-based positive electrode material and preparation method thereof

Abstract

The invention belongs to the field of new energy automobile battery electrode materials, and particularly relates to a long-circulation high-capacity retention rate lithium-rich manganese-based positive electrode material and a preparation method thereof.The preparation method comprises the following steps that a lithium source, a nickel source, a cobalt source, a manganese source and citric acid serving as a complexing agent are weighed according to a certain stoichiometric ratio and dissolved in deionized water, zinc phosphate is added, citric acid is added as the complexing agent, stirring is conducted, and a mixture is obtained; uniformly stirring to obtain a precursor salt solution; performing high-temperature spray drying on the precursor solution to obtain precursor powder of the material; and calcining the precursor powder at high temperature to obtain modified positive electrode material powder. The conductivity of the material can be effectively improved, so that the electrochemical performance of the battery is improved, and the capacity retention rate is high; the preparation method is simple, lithium-nickel mixed arrangement can be efficiently and effectively reduced, Jahn-Teller distortion can be effectively inhibited, the obtained button cell shows excellent cycle stability, and the capacity retention rate reaches 97.72% within 2-4.8 V voltage and 400 cycles of 1 C current.

Description

Technical Field

[0001] This invention belongs to the field of electrode materials for new energy vehicle batteries, specifically relating to a lithium-rich manganese-based cathode material with high capacity retention during long cycles and its preparation method. Background Technology

[0002] Currently, with the rise of smart energy, the global energy landscape is undergoing profound adjustments, and renewable energy technologies, smart grids, and electric vehicles are experiencing dramatic changes. As the core of electric vehicles, lithium-ion batteries have seen rapid development in recent years due to their higher energy density and longer lifespan. As the most successful commercially available battery, its applications have expanded from 3C (computers, communications, and consumer electronics) to electric vehicles, and even to military applications such as drones and large-scale energy storage. The pursuit of higher energy density is increasing, making it undoubtedly one of the most successful energy storage devices in changing people's lifestyles. As the most crucial element in improving the performance of lithium-ion batteries—the cathode material—commercially available layered oxide cathode materials include LiCoO2 (LCO) and LiNi. x Co y Mn z O2(NCM xyz Spinel-structured LiMn2O4 and polyanionic LiFePO4 (LFP) cathode materials are insufficient to meet the cathode material requirements of high-energy-density lithium-ion batteries (≥ 400 Wh / kg).

[0003] Lithium-rich manganese cathode materials are considered the most promising next-generation lithium-ion battery cathode materials, exhibiting a capacity exceeding 250 mAh g⁻¹. -1 Specific capacitance and over 3.5 V (vs. Li / Li + The median discharge voltage of lithium-rich manganese-based cathode materials has attracted increasing attention due to their unique advantages: high specific capacity, high energy density, and long cycle life. However, as a cathode material, it still faces many problems and challenges. For example, the redox reaction of anionic oxygen during charging and discharging is the source of high energy density, but it also generates a series of problems that affect the cycle stability of lithium-rich manganese-based cathode materials.

[0004] Lithium-rich manganese-based cathode materials cannot be commercially applied due to capacity decay. Therefore, they need to be modified to improve cycle stability and achieve large-scale application. Common modification methods include surface modification and element doping, such as coating the surface of lithium-rich manganese-based materials with elements like Li3PO4. [1] ) or elemental doping (Mg²⁺ [2] Al³⁺ [3]Improve cycle stability. (In "X. Zhang, R. Yu, Y. Huang, X. Wang, Y. Wang, B. Wu, Z. Liu, J. Chen, Acs Sustainable Chemistry&Engineering In 2018, 6, 12969, this method prepared 3wt% Li3PO4-coated Li using a solvothermal method and a high-temperature solid-state method. 1.2 Mn 0.54 Ni 0.13 Co 0.13 O2, after 200 cycles at 0.5C, retained 85.3% of its capacity, but its initial discharge specific capacity was only 277.1 mAh g⁻¹. -1 . In “W. Zhang, Y. Sun, H. Deng, J.Ma, Y. Zeng, Z. Zhu, Z. Lv, H. Xia, X. Ge, S. Cao, Advanced Materials In 2020, 32,2000496, the method involves coating the surface of lithium-rich materials with magnesium titanate. The high affinity of magnesium and titanium elements effectively stabilizes the surface oxygen of the lithium-rich materials by enhancing the energy barrier of the oxygen release reaction, resulting in significantly improved cycle performance. After 700 cycles at 2C (1C = 250 mg⁻¹), the capacity retention rate is approximately 81%. However, the core idea of ​​this method is to generate a new phase through interfacial diffusion reaction of solid raw materials at high temperatures. Its inherent drawbacks, including slow reaction rate, high energy consumption, and the tendency to lead to uneven product composition, remain. In "K. Zhou, Z. Zhang, B. Cao, S. Jiao, J. Zhu, X. Xu, P. Chen, X.Xiong, L. Xu, Q. Wang,"... Nano EnergyIn the paper "2025, 135, 110639," the method utilizes aluminum sulfate to modify the surface of cobalt-free lithium-rich manganese materials (LRMS), demonstrating that surface aluminum doping and an amorphous lithium sulfate coating can promote lithium-ion diffusion and reduce irreversible oxygen loss. The improved LRMS retained 93.8% of its capacity after 500 cycles. However, this processing involves complex chemical reaction conditions (such as temperature and time control), increasing the difficulty and cost of large-scale production. Furthermore, controlling the uniformity and consistency of byproducts introduced during the process (such as the amorphous lithium sulfate coating) is also a challenge. In summary, the above methods improve the cycling performance of lithium-rich manganese materials to some extent, but some problems remain: excessive coating layers can hinder electron / ion transport, leading to a decrease in conductivity at the expense of some initial capacity. The elemental doping method often requires secondary temperature-controlled calcination, which is cumbersome and difficult to control, causing agglomeration and resulting in poor cycling performance and rapid conductivity decline.

[0005] Therefore, there is an urgent need for simpler and easier modification methods to achieve a balance between capacity and cycle performance. Summary of the Invention

[0006] To address the problems of low initial discharge specific capacity, poor cycle stability, and complex preparation processes in lithium-rich manganese-based cathode materials, this invention provides a method for preparing lithium-rich manganese-based cathode materials with high capacity retention over long cycles. This invention is a one-step synthesis method based on Zn3(PO4)2 modification. This method introduces an appropriate amount of zinc phosphate into the precursor solution, combined with high-temperature spray drying and calcination processes, to achieve uniform doping and surface modification of zinc phosphate in the material, thereby significantly improving the electrochemical performance of the material.

[0007] To achieve the above objectives, the technical solution provided by this invention is: a method for preparing a lithium-rich manganese-based cathode material with high capacity retention over long cycles, comprising the following steps: Step 1: Weigh lithium source, nickel source, cobalt source, manganese source, and complexing agent citric acid according to a certain stoichiometric ratio, dissolve them in deionized water, add zinc phosphate, add citric acid as a complexing agent, and stir evenly to obtain a precursor salt solution. Step 2: Obtain the precursor powder of the material by high-temperature spray drying of the precursor solution; Step 3: The above precursor powder is calcined at high temperature to obtain modified cathode material powder.

[0008] Furthermore, in step one above, zinc phosphate is dissolved in a certain molar ratio, with a concentration of 0.001~0.0033 mol / L.

[0009] Furthermore, the lithium source, nickel source, cobalt source, and manganese source mentioned above are selected from hydrated acetate; the complexing agent is citric acid monohydrate.

[0010] Furthermore, in step one above, the concentrations of the lithium source, nickel source, cobalt source, and manganese source solutions are 0.15 mol / L; the concentration of the complexing agent is 0.3 mol / L.

[0011] Furthermore, the magnetic stirring speed in step one above is 500 r / min, and the stirring time is 1 h.

[0012] Furthermore, in the spray drying process of step two above, the inlet and outlet temperatures are set to 230℃ and 120℃ respectively, and the peristaltic speed is set to 18 rpm.

[0013] Furthermore, in step three, the high-temperature sintering is specifically carried out by heating the temperature to 1000 ℃ at a rate of 3 ℃ / min, holding it at that temperature for 20 min, and then naturally cooling it to room temperature.

[0014] Furthermore, the above-mentioned preparation method yields a lithium-rich manganese-based cathode material with high capacity retention during long-cycle operation.

[0015] Compared with the prior art, the advantages of the present invention are: 1. This invention improves the agglomeration problem of lithium-rich manganese-based cathode materials by modifying them with zinc phosphate and appropriately doping them. This is because the good particle dispersibility of zinc phosphate increases the coordination sites for active metals such as nickel and cobalt, thereby enhancing the effective redox reaction. Furthermore, the good particle dispersibility of zinc phosphate alleviates the agglomeration problem by exposing more particle crystal faces, increasing the specific surface area of ​​the particles, providing more active sites, promoting electron transport, and shortening the Li-C reaction time. + This diffusion pathway improves the conductivity of the material, making electrochemical reactions easier to occur and thus enhancing the electrochemical performance of the battery.

[0016] 2. This invention effectively reduces lithium-nickel mixing by modifying lithium-rich manganese-based cathode materials with zinc phosphate. Furthermore, zinc phosphate modification reduces Mn content. 3 The relative content of ⁺ effectively suppresses Jahn-Teller distortion, significantly improves the stability of the material, and enhances its cycling performance. The material can still efficiently utilize active substances during cycling, exhibiting high capacity retention.

[0017] 3. This invention utilizes appropriate zinc phosphate doping, where PO4³⁻ bonds with surface lattice oxygen, thereby forming more oxygen vacancies. The increased number of oxygen vacancies generates localized strain, inducing lattice contraction and reducing the valence state of surrounding transition metals. The abundance of oxygen vacancies helps suppress lattice oxygen oxidation and simultaneously provides additional Li₂. + Diffusion channels, reducing Li + Diffusion barrier.

[0018] 4. The doping and precursor elements of this invention are prepared using a "one-pot spray" method, which is simple, efficient, and avoids the component segregation caused by traditional step-by-step modification. The coin cells prepared using this invention exhibit excellent cycle stability, maintaining 97.72% capacity after 400 cycles at 1 C current within a voltage range of 2-4.8 V. Attached Figure Description

[0019] Figure 1 The images show the XRD patterns before cycling for Examples 1, 2, and 3 and Comparative Example 1. Figure 2 The images shown are SEM images of Examples 1, 2, and 3 and Comparative Example 1 before cycling. Figure 2 (a) is the pre-cycle SEM of Comparative Example 1. Figure 2 (b) is the SEM before the cycle in Example 1. Figure 2 (c) is the SEM before the cycle in Example 2. Figure 2 (d) is the SEM before the cycle in Example 3; Figure 3 The following are XPS fitting plots of each element after 200 cycles for Examples 1, 2, 3 and Comparative Example 1, where... Figure 3 (a) O1s fit for Comparative Example 1 and Examples 1, 2, and 3, Figure 3 (b) Ni-2p fitting for Comparative Example 1 and Examples 1, 2, and 3, Figure 3 (c) Mn-2p fitting for Comparative Example 1 and Examples 1, 2, and 3, Figure 3 (d) Zn-2p fitting for Comparative Example 1 and Example 2 with the best electrochemical performance. Figure 3 (e) P-2p fitting for Comparative Example 1 and Example 2 with the best electrochemical performance; Figure 4 The images show the Raman plots of Comparative Example 1, Examples 1, 2, and 3 before and after 200 cycles, respectively. Figure 4 (a) Raman for Comparative Example 1 and Examples 1, 2, and 3 without cycling. Figure 4 (b) Raman fitting plots after 200 cycles for Comparative Example 1 and Examples 1, 2, and 3; Figure 5 The EIS graphs are those of Examples 1, 2, 3 and Comparative Example 1 after 200 cycles; Figure 6 The following are GITT plots of Examples 1, 2, and 3 and Comparative Example 1, wherein... Figure 6 (a) GITT during the charging process, Figure 6 (b) GITT during the discharge process; Figure 7 The first charge-discharge curves of Examples 1, 2, 3 and Comparative Example 1 at 0.1C are shown. Figure 8 This is a comparison chart of 500 cycles at 1°C for Examples 1, 2, and 3 and Comparative Example 1; Figure 9 This is a comparison chart of the rate performance of Examples 1, 2, and 3 with Comparative Example 1; Figure 10 The capacity differential curves of Example 2 and Comparative Example 1 show the optimal cycling performance, where... Figure 10 (a) is the capacity differential curve for 200 cycles of Comparative Example 1, where Figure 10 (b) Capacity differential curves after 200 cycles for Example 2 with the best electrochemical performance; Detailed Implementation

[0020] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0021] Example 1: A method for preparing a lithium-rich manganese-based cathode material with high capacity retention over long cycles, comprising the following steps: Step 1: Weigh the acetates containing Li, Ni, Co, and Mn elements according to the molar ratio shown in the chemical formula, dissolve them in deionized water, and prepare a mixed salt solution with a concentration of 0.15 mol / L. The molar ratio of the acetates containing Li, Ni, Co, and Mn elements is 2.7:0.4:0.4:1.6. Add citric acid monohydrate and zinc phosphate as complexing agents and dopant sources, with concentrations of 0.15 mol / L and 0.001 mol / L, respectively. Place the mixed solution in a magnetic stirrer, set the speed to 500 r / min, and stir for 1 h.

[0022] Step 2: The above mixed solution is granulated using a spray dryer to prepare the precursor. The liquid feed rate is 10 ml / min, the inlet air temperature of the spray dryer is 230℃, the outlet air temperature is 120℃, and the peristaltic speed is 18 rpm.

[0023] Step 3: The precursor obtained by spraying is placed into an alumina crucible and heated to 1000℃ in a box furnace at a rate of 3℃ / min, held for 20 min, and then naturally cooled to room temperature to obtain the cathode material Li. 1.2 Co 0.13 Ni 0.13 Mn 0.54 O2-0.001Zn3(PO4)2.

[0024] Example 2: The preparation method is basically the same as in Example 1, except that the concentration of zinc phosphate added in step 1 is 0.002 mol / L, resulting in the positive electrode material Li. 1.2 Co 0.13 Ni0.13 Mn 0.54 O2-0.002Zn3(PO4)2.

[0025] Example 3: The preparation method is basically the same as that of Example 1, except that the concentration of zinc phosphate added in step 1 is 0.0033 mol / L, resulting in the positive electrode material Li. 1.2 Co 0.13 Ni 0.13 Mn 0.54 O2-0.0033Zn3(PO4)2.

[0026] Comparative Example 1: Preparation of Lithium-Rich Manganese-Based Cathode Material Li 1.2 Ni 0.13 Co 0.13 Mn 0.54 The preparation method for O2 is basically the same as that in Example 3, except that zinc phosphate is not added in step 1.

[0027] The cathode material powders prepared in Examples 1-3 and Comparative Example 1 were mixed with super p powder and 1.2% CMC aqueous solution at a mass ratio of 253:32:1250. After ball milling for 4 hours, the mixture was coated onto aluminum foil, vacuum dried at 110 °C for 20 hours, cut into electrode sheets, and then vacuum dried for another 10 hours before being transferred into a glove box for assembling coin cells. Tests were conducted, and the results are as follows: Electrochemical tests showed that adding 0.001 mol of zinc phosphate in Example 1 significantly increased the initial discharge specific capacity (compared to Comparative Example 1). Further addition resulted in an even greater increase in discharge specific capacity, as shown in Example 2. However, excessive addition led to a slight decrease in discharge specific capacity. Overall, Example 2 exhibited the best performance, maintaining a capacity retention of 97.72% after 400 cycles at 1 C. Even at high rates of 5 C and 10 C, Example 2 also demonstrated 145 and 112 mAh g⁻¹, respectively. -1 Its high capacity demonstrates excellent rate performance.

[0028] Figure 1As shown, the XRD comparison diagrams before cycling of Comparative Example 1, Example 1, Example 2, and Example 3 are shown. It can be seen that the peak shape is consistent before and after the addition of zinc phosphate, and there are no obvious impurity peaks, indicating that the addition of zinc phosphate does not affect the structure of lithium-rich manganese-based cathode materials. The difference is that the 003 / 104 ratio gradually increases with the addition of zinc phosphate content, and the orderliness increases, indicating that appropriate orderliness is beneficial to improving electrochemical performance. As the zinc phosphate content increases excessively, the 003 / 104 ratio decreases slightly, which may be because the excess PO4³⁻ forms Li3PO4 microcrystals at the grain boundaries, resulting in interlayer slippage and the local appearance of LiMn2O4 spinel phase, which broadens the (003) peak and decreases in intensity. As the zinc phosphate content increases, the 003 peak shifts to a higher angle, indicating that the material structure has undergone significant lattice contraction. PO4³⁻ bonds with oxygen in the surface lattice, thereby forming more oxygen vacancies. The increased oxygen vacancies cause strain, which induces lattice contraction. Appropriately reducing the c-axis helps to reduce structural stress and strain caused by volume expansion and contraction during cycling, thereby reducing the risk of particle cracking or breakage, helping to maintain the integrity of the material structure and improve cycling stability.

[0029] Figure 2 As shown, the SEM images before cycling are those of Comparative Example 1, Examples 1, 2, and 3. It can be seen that... Figure 2 (b) Figure 2 (c) and Figure 2 In (d), zinc phosphate modification effectively improved the agglomeration problem of lithium-rich manganese particles. Good particle dispersion increased the coordination sites for active metals such as nickel and cobalt, thereby enhancing the effectiveness of redox reactions. Furthermore, the alleviation of agglomeration exposed more particle crystal faces, increasing the specific surface area of ​​the particles, providing more active sites, promoting electron transport, and shortening the Li-C reaction time. + Diffusion pathways are used to improve the electrical conductivity of materials, making electrochemical reactions easier to occur. Among them, the diffusion pathway is used to improve the electrical conductivity of materials. Figure 2 c (Example 2 is the optimal one).

[0030] Figure 3 The figure shows the element XPS fit after 200 cycles for Comparative Examples 1, 1, 2, and 3. It can be seen that... Figure 3 In (a), O in Example 2 V The content was significantly increased (43.23%), reflecting a richer oxygen defect on the sample surface. Appropriate zinc phosphate doping allows PO4³⁻ to bond with surface lattice oxygen, thus forming more oxygen vacancies. More oxygen vacancies help suppress lattice oxygen oxidation and reduce oxygen evolution. Figure 3 As can be seen in (b), Ni in all samples 3+ The proportion of Ni is high 2+ And in Example 3, Ni 3+The highest content (67.89%) helps slow down migration to the Li layer. From Figure 3 As can be seen in (c), Mn in Example 2 4+ Mn has the highest proportion 4 ⁺(d³, t2g³ eg 0 It does not exhibit the Jahn-Teller effect; its octahedral structure is highly symmetrical and stable. High Mn content 4 ⁺ can act as a "structural pillar," suppressing Jahn-Teller distortion and effectively inhibiting manganese dissolution, thereby improving cycle life. From Figure 3 As can be seen in (d), compared with Comparative Example 1, the peak intensities of Zn2p1 / 2 and Zn2p3 / 2 in Example 2 are significantly enhanced, and the peak shapes are sharper, indicating that the chemical environment of zinc in the sample is more uniform. In contrast, Comparative Example 1, because it is undoped, does not show the XPS characteristic peaks of Zn. Figure 3 As can be seen in (e), the XPS of the same P-2p indicates that the sample of Example 2 with the best cycling stability has moderately effective phosphate doping, while Comparative Example 1 has no obvious P-2p characteristic peak.

[0031] Figure 4 As shown, the Raman plots for Comparative Example 1, Examples 1, 2, and 3 are shown before and after 200 cycles. Figure 4 As can be seen in (a), in the Raman spectrum, 422 cm⁻¹ -1 The characteristic peak at 477 cm⁻¹ confirms the presence of the monoclinic Li₂MnO₃ component. -1 and 596 cm -1 The peak at 677 cm⁻¹ can be attributed to the O-TM-O bending vibration (Eg mode) and TM-O stretching vibration (A1g mode) in the layered R-3m structure. Notably, Example 2 shows a stronger TM-O stretching vibration. The Raman spectrum of the sample at 677 cm⁻¹... -1 A more significant high wavenumber characteristic peak appears at [location missing], which originates from the formation of a spinel structure, indicating that the material underwent a spinel phase transition after 200 cycles. This may be the reason for the capacity decay after long cycling. From [location missing] Figure 4 As can be seen in (b), the spinel phase content in Comparative Example 1 is the highest at 6.21%, while that in Example 2 is the lowest at 1.81%, indicating that the doping of (Zn3(PO4)2) reduces the formation of the spinel phase during the cycling process.

[0032] Figure 5The figure shows the EIS impedance test results after 200 cycles for Comparative Example 1, Examples 1, 2, and 3. It can be seen that Example 2 has the lowest charge transfer impedance Rct, at 157 Ω. This indicates that moderate zinc phosphate doping effectively alleviates the lithium-rich manganese agglomeration problem, exposes more particle crystal faces, increases the specific surface area of ​​the particles, provides more active sites, promotes electron transport, and shortens the Li-C-C-Tc cycle. + Diffusion pathway.

[0033] Figure 6 Further GITT tests were performed on Comparative Example 1, Examples 1, 2, and 3. Figure 6 The test results (a) and (b) show that Example 2 exhibits the highest Li during both charge and discharge periods. + Diffusion rate; Comparative Example 1: Undoped Li + The diffusion rate is relatively poor.

[0034] Figure 7 As shown, the first discharge curves of Comparative Examples 1, 2, and 3 and Examples 1, 2, and 3 are shown. It can be seen that Example 2 has the largest first discharge capacity, which is 305.04 mAh / g.

[0035] Figure 8 The figure shows a comparison of the cycling performance of Comparative Examples 1, 2, and 3 with Examples 1, 2, and 3. It can be seen that after 400 cycles at 1C, Examples 1, 2, and 3 exhibit capacity retention rates of 96.00%, 97.72%, and 96.39%, respectively. Example 2, with the optimal zinc phosphate doping content, demonstrates the best capacity retention rate. In contrast, Comparative Example 1, without zinc phosphate doping, shows a capacity retention rate of only 74.66%.

[0036] Figure 9 The figure shows the rate performance test results of Comparative Example 1 and Examples 1, 2, and 3. It can be seen that Example 2 has the best rate performance, achieving 130.07 and 104.21 mAh g⁻¹ at high rates of 5C and 10C, respectively. -1 High capacity.

[0037] Figure 10 As shown, the capacity differential curves for Example 2 and Comparative Example 1 are... Figure 10 The test results (a) and (b) show that in Example 2, the peak shape and position of the dQ / dV curve remained good with increasing cycle number (from 4th to 200th), indicating that the material has a stable structure, good phase transition reversibility (δV=0.414V), and small capacity decay during cycling. The plateau width and peak height remained basically stable after cycling, indicating that the material can still efficiently utilize the active material and has a high capacity retention rate during cycling.

[0038] In summary, Example 2 is the best embodiment.

[0039] The above are merely specific embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing a lithium-rich manganese-based cathode material with high capacity retention during long-cycle operation, characterized in that: Includes the following steps: Step 1: Weigh lithium source, nickel source, cobalt source, manganese source, and complexing agent citric acid according to a certain stoichiometric ratio, dissolve them in deionized water, add zinc phosphate, add citric acid as a complexing agent, and stir evenly to obtain a precursor salt solution. Step 2: Obtain the precursor powder of the material by high-temperature spray drying of the precursor solution; Step 3: The above precursor powder is calcined at high temperature to obtain modified cathode material powder.

2. The method for preparing a lithium-rich manganese-based cathode material with high capacity retention during long-cycle operation according to claim 1, characterized in that: In step one, zinc phosphate is dissolved in a certain molar ratio, with a concentration of 0.001~0.0033 mol / L.

3. The method for preparing a lithium-rich manganese-based cathode material with high capacity retention during long-cycle operation according to claim 1, characterized in that: The lithium, nickel, cobalt, and manganese sources are selected from hydrated acetates; the complexing agent is citric acid monohydrate.

4. The method for preparing a lithium-rich manganese-based cathode material with high capacity retention during long-cycle operation according to claim 1, characterized in that: In step one, the concentrations of the lithium source, nickel source, cobalt source, and manganese source solutions are 0.15 mol / L; the concentration of the complexing agent is 0.3 mol / L.

5. The method for preparing a lithium-rich manganese-based cathode material with high capacity retention during long-cycle operation according to claim 1, characterized in that: The magnetic stirring speed in step one is 500 r / min, and the stirring time is 1 h.

6. The method for preparing a lithium-rich manganese-based cathode material with high capacity retention during long-cycle operation according to claim 1, characterized in that: In step two, the inlet and outlet temperatures during the spray drying process are set to 230°C and 120°C, respectively, and the peristaltic speed is set to 18 rpm.

7. The method for preparing a lithium-rich manganese-based cathode material with high capacity retention during long-cycle operation according to claim 1, characterized in that: The third step, high-temperature sintering, involves heating to 1000℃ at a rate of 3℃ / min, holding at that temperature for 20 minutes, and then naturally cooling to room temperature.

8. The lithium-rich manganese-based cathode material with high capacity retention during long-cycle operation, prepared by the method according to claim 1.

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