Nanofiber-coated lithium-rich manganese-based positive electrode material as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of battery materials, and particularly relates to a nanofiber-coated lithium-rich manganese-based positive electrode material as well as a preparation method and application thereof. The invention provides a preparation method of a coated nanofiber lithium-rich manganese-based positive electrode material, which comprises the following steps: (1) mixing a first high-molecular polymer, a lithium-rich manganese-based precursor, a lithium salt and a first solvent to prepare an inner-layer spinning solution; (2) mixing a second high-molecular polymer, a solid electrolyte and a second solvent to prepare an outer-layer spinning solution; (3) performing coaxial electrostatic spinning and sintering by taking the inner-layer spinning solution as an inner layer and the outer-layer spinning solution as an outer layer; the sintering atmosphere comprises argon and oxygen, and the volume ratio of the argon to the oxygen is (2-5): 1; the first high-molecular polymer is different from the second high-molecular polymer. The battery prepared from the nanofiber-coated lithium-rich manganese-based positive electrode material prepared by the invention has excellent first effect, specific capacity, rate capability and cycle performance.

Description

Technical Field

[0001] This invention belongs to the field of battery materials technology, specifically relating to a lithium-rich manganese-based cathode material coated with nanofibers, its preparation method, and its application. Background Technology

[0002] All-solid-state lithium batteries have attracted much attention due to their advantages such as high energy density, long cycle life, and high safety. However, traditional solid electrolytes suffer from problems such as low ionic conductivity, high interfacial impedance, and insufficient mechanical strength, which limit their application and promotion. Among existing technologies, lithium-rich manganese-based materials are currently a key focus of development as cathode materials, offering advantages such as low cost, high capacity, and a wide voltage window, making them highly suitable for solid-state battery systems. However, the solid-solid contact between solid electrolytes and lithium-rich manganese-based cathode materials differs from the liquid-solid contact between liquid electrolytes and cathode materials. Solid-solid contact cannot achieve complete contact, and the contact surface is limited, leading to interfacial contact problems that result in low ion migration efficiency, restricted lithium-ion transport paths, and poor interfacial stability. Summary of the Invention

[0003] Therefore, the technical problem to be solved by the present invention is to overcome the defects in the preparation of all-solid-state lithium batteries in the prior art, such as low ion migration efficiency, limited lithium ion transport path leading to poor electrical performance, and poor interface stability leading to poor cycle performance. Thus, the present invention provides a lithium-rich manganese-based cathode material coated with nanofibers, its preparation method and application.

[0004] To this end, the present invention provides the following technical solution.

[0005] This invention provides a method for preparing a lithium-rich manganese-based cathode material coated with nanofibers, comprising the following steps:

[0006] (1) The first polymer, lithium-rich manganese-based precursor, lithium salt and first solvent are mixed to prepare inner spinning solution;

[0007] (2) The second polymer, solid electrolyte and second solvent are mixed to prepare the outer spinning solution;

[0008] (3) Coaxial electrospinning and sintering are performed using the inner spinning solution as the inner layer and the outer spinning solution as the outer layer.

[0009] The sintering atmosphere includes argon and oxygen, with a volume ratio of argon to oxygen of (2-5):1; the first polymer and the second polymer are different.

[0010] This invention utilizes coaxial electrospinning combined with specially prepared inner and outer spinning solutions to prepare lithium-rich manganese-based cathode materials with inner and outer layer structures coated nanofibers. When parallel spinning or multi-component spinning is used, it is impossible to prepare lithium-rich manganese-based cathode materials with an outer layer coated with a solid electrolyte. When these materials come into contact with the solid electrolyte in a solid-state battery system, interfacial contact problems easily occur, leading to a decrease in electrical performance.

[0011] If the first and second polymers are different, and the inner and outer spinning solutions contain the same polymer, the inner and outer layers will dissolve in each other during coaxial electrospinning. This will prevent the formation of lithium-rich manganese-based cathode materials with inner and outer layer structures. Furthermore, interfacial contact problems will easily occur when these materials come into contact with the solid electrolyte in a solid-state battery system, leading to a decrease in electrical performance.

[0012] If lithium-rich manganese-based cathode materials and solid electrolytes are directly mixed and coated, the coating uniformity is poor, and the solid electrolyte cannot make good contact with the solid electrolyte in the solid system, which easily leads to interface contact problems and a significant decrease in the electrical performance of the battery.

[0013] In one optional embodiment, step (1), the specific steps of mixing, include: dissolving the first polymer in a first solvent, first stirring, adding a lithium-rich manganese-based precursor and a lithium salt, and second stirring;

[0014] Preferably, the first stirring time is 2-6 hours;

[0015] Preferably, the second stirring time is 10-16 hours;

[0016] The first solvent can be any common organic solvent in the art. This invention does not make any specific limitations. As an example, N,N-dimethylformamide is used.

[0017] In one optional embodiment, step (2), the specific steps of mixing, include: dissolving the second polymer in a second solvent, stirring, adding a solid electrolyte, and stirring again.

[0018] Preferably, the third stirring time is 2-6 hours;

[0019] Preferably, the fourth stirring time is 10-16 hours;

[0020] The second solvent can be any solvent commonly used in the art. This invention does not impose any specific limitations. As an example, N,N-dimethylformamide is used.

[0021] Preferably, the volume ratio of the argon gas to the oxygen gas is (3-4):1;

[0022] In one optional embodiment, the ratio of the mass of the first polymer to the volume of the first solvent is (15-20):100, where the mass is in g and the volume is in ml.

[0023] In one optional embodiment, the ratio of the mass of the second polymer to the volume of the second solvent is (10-15):100, where the mass is in g and the volume is in ml.

[0024] In one alternative embodiment, the first polymeric material comprises at least one of PVP, SAN, and PAN.

[0025] In one alternative embodiment, the second polymer comprises at least one of PVP, SAN, and PAN;

[0026] As an example, when the first polymer is PVP, the second polymer can be SAN and / or PAN; when the first polymer is PAN, the second polymer can be PVP and / or SAN; when the first polymer is SAN, the second polymer can be PVP and / or PAN; when the first polymer is PVP and SAN, the second polymer can be PAN; when the first polymer is PVP and PAN, the second polymer can be SAN; when the first polymer is SAN and PAN, the second polymer can be PVP.

[0027] In one optional embodiment, the solid electrolyte comprises at least one of LATP, LLZO, and LAGP. LATP is lithium aluminum titanium phosphate; LLZO is lithium lanthanum zirconium oxide; and LAGP has the chemical formula Li. 1.5 Al 0.5 Ge 1.5 (PO4)3;

[0028] In one optional embodiment, in step (1), the mass ratio of the first polymer and the lithium-rich manganese-based precursor is 1:(0.5-2).

[0029] In one optional embodiment, in step (2), the mass ratio of the second polymer to the solid electrolyte is 1:(0.1-0.4).

[0030] Preferably, in step (2), the mass ratio of the polymer to the solid electrolyte is 1:(0.25-0.3).

[0031] In one optional embodiment, the sintering process includes heating sintering and cooling sintering.

[0032] Preferably, the heating sintering includes a first sintering, a second sintering, and a third sintering;

[0033] Preferably, the cooling sintering is performed after the heating sintering.

[0034] In one optional embodiment, the heating rate of the sintering is 2-4°C / min;

[0035] In one optional embodiment, the temperature of the first sintering is 220-280°C;

[0036] In one optional embodiment, the first sintering time is 0.5-2 hours;

[0037] In one optional embodiment, the temperature of the second sintering is 650-700°C;

[0038] In one optional embodiment, the second sintering time is 4-6 hours;

[0039] In one optional embodiment, the temperature of the third sintering is 920-960°C;

[0040] In one optional embodiment, the third sintering time is 8-12 hours;

[0041] In one optional embodiment, the cooling rate of the cooling sintering is 0.5-1.5℃ / min;

[0042] In one optional embodiment, the cooling sintering temperature is 550-650°C;

[0043] In one optional embodiment, the cooling sintering time is 0.5-2 hours.

[0044] After cooling and sintering, the temperature is allowed to drop naturally to room temperature.

[0045] In one optional embodiment, the lithium-rich manganese-based precursor includes at least one of nickel manganese hydroxide and nickel cobalt manganese hydroxide;

[0046] In one alternative embodiment, the lithium salt includes at least one of lithium acetate, lithium hydroxide, and lithium carbonate;

[0047] In one optional embodiment, the molar ratio of the lithium-rich manganese-based precursor to the lithium salt is 1:(1.3-1.5).

[0048] In one optional embodiment, the molar ratio of nickel to manganese in the lithium-rich manganese-based precursor is (35-40):(60-65).

[0049] In one optional embodiment, the voltage of the coaxial electrospinning is 10-16kV;

[0050] In one optional embodiment, the feed rate of the coaxial electrospinning is 0.2-0.6 mL / h;

[0051] In one optional embodiment, the receiving distance of the coaxial electrospinning is 16-20 cm.

[0052] The present invention also provides a lithium-rich manganese-based cathode material coated with nanofibers prepared by the above preparation method.

[0053] The present invention also provides an application of the lithium-rich manganese-based cathode material coated with nanofibers prepared by the above preparation method in lithium-ion batteries or electrodes.

[0054] The technical solution of this invention has the following advantages:

[0055] 1. The preparation method of the coated nanofiber lithium-rich manganese-based cathode material provided by the present invention includes the following steps: (1) mixing a first polymer, a lithium-rich manganese-based precursor, a lithium salt and a first solvent to obtain an inner spinning solution; (2) mixing a second polymer, a solid electrolyte and a second solvent to obtain an outer spinning solution; (3) performing coaxial electrospinning with the inner spinning solution as the inner layer and the outer spinning solution as the outer layer, and sintering; the sintering atmosphere includes argon and oxygen, and the volume ratio of argon to oxygen is (2-5):1; the first polymer and the second polymer are different. The coated nanofiber lithium-rich manganese-based cathode material provided by the present invention has a moderate specific surface area, which can improve the electrical performance of the battery by increasing the contact with the solid electrolyte, while also preventing the battery from overcharging rapidly and the cycle performance from decreasing rapidly when the surface area is too large. This invention prepares a lithium-rich manganese-based precursor nanofiber membrane coated with a solid electrolyte by coaxial electrospinning of inner and outer spinning solutions. The resulting coated lithium-rich manganese-based cathode material has a framework of carbon nanofibers formed by the sintering of a first polymer and a small amount of a second polymer. The carbon nanofibers have good conductivity, which can greatly improve the ionic conductivity and enhance the first-time efficiency, specific capacity, rate performance, and cycle performance of the cathode material. The solid electrolyte is coated on the outside of the material, which allows for better contact between the solid electrolyte coating layer and the solid electrolyte in the solid battery system, reducing interfacial contact problems and improving the battery's electrical performance.

[0056] This invention incorporates a polymer into the spinning solution. During sintering, the polymer forms a carbon skeleton support material, which supports the cathode material film and provides flexibility for contact with the solid electrolyte, increasing the contact area and thus improving ion migration efficiency and lithium-ion transport paths. Simultaneously, the carbon skeleton also exhibits good conductivity, enhancing ionic conductivity and significantly improving the battery's initial efficiency, specific capacity, rate performance, and cycle performance. Furthermore, the carbon skeleton increases the mechanical strength of the lithium-rich manganese-based cathode material, preventing brittle fracture during contact with the solid electrolyte. This invention controls the sintering atmosphere to include argon and oxygen, with a volume ratio of argon to oxygen of (2-5):1. This prevents the solid electrolyte from being reduced in a pure argon atmosphere, hindering ion conduction, and prevents the polymer from being completely oxidized in a pure oxygen atmosphere, thus preventing the formation of the carbon skeleton support material.

[0057] This invention employs a coaxial electrospinning process to prepare solid electrolyte-coated nanofiber lithium-rich manganese-based cathode material in one step. The preparation method is simple and forms a coated nanofiber lithium-rich manganese-based cathode material with inner and outer layer structures. These inner and outer layer structures, together with the pores formed by the polymer during sintering, solve the volume expansion of the cathode material during charging and discharging, improve the stability of the cathode material, and thus enhance the cycle performance of the battery.

[0058] 2. The method for preparing the coated nanofiber lithium-rich manganese-based cathode material provided by the present invention preferably has a volume ratio of argon to oxygen of (3-4):1, which results in better electrical performance; preferably, the mass ratio of polymer to solid electrolyte is 1:(0.25-0.3), which further improves the uniformity of the coating layer and the ion transport performance, thereby improving the electrical performance of the cathode material. Detailed Implementation

[0059] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0060] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0061] Example 1

[0062] This embodiment provides a method for preparing a lithium-rich manganese-based cathode material coated with nanofibers, including the following steps:

[0063] (1) Dissolve 2g PAN in 10ml DMF solution, stir for 3h, and add 2g Ni. 0.35 Mn 0.65 (OH)2 and 2g of lithium acetate were stirred for 12h to obtain the inner spinning solution;

[0064] (2) Dissolve 2g PVP in 20ml DMF solution, stir for 3h, add 0.5g LATP, stir for 12h to obtain outer spinning solution;

[0065] (3) The inner spinning solution and the outer spinning solution are used to make a nanofiber membrane by coaxial electrospinning process. The voltage of the coaxial electrospinning process is 14kV, the feed speed is 0.5mL / h, and the receiving distance is 18cm.

[0066] (4) The nanofiber membrane was placed in an atmosphere furnace. The atmosphere of the atmosphere furnace was argon and oxygen in a volume ratio of 4:1. The temperature program was set to heat the membrane from room temperature to 260°C at a heating rate of 3°C / min and hold it for 1 hour, then heat it to 700°C at a heating rate of 3°C / min and hold it for 6 hours, then heat it to 940°C at a heating rate of 3°C / min and hold it for 10 hours, and then cool it down to 600°C at a cooling rate of 1°C / min and hold it for 1 hour to obtain the lithium-rich manganese-based cathode material coated with nanofiber.

[0067] Example 2

[0068] This embodiment provides a method for preparing a lithium-rich manganese-based cathode material coated with nanofibers. The only difference from Example 1 is that in step (4), the atmosphere of the atmosphere furnace is argon and oxygen with a volume ratio of 2:1 instead of argon and oxygen with a volume ratio of 4:1 in Example 1.

[0069] Example 3

[0070] This embodiment provides a method for preparing a lithium-rich manganese-based cathode material coated with nanofibers. The only difference from Example 1 is that in step (4), the atmosphere of the atmosphere furnace is argon and oxygen with a volume ratio of 5:1 instead of argon and oxygen with a volume ratio of 4:1 in Example 1.

[0071] Example 4

[0072] This embodiment provides a method for preparing a lithium-rich manganese-based cathode material coated with nanofibers. The only difference from Example 1 is that in step (2), 0.4g LATP is added instead of 0.5g LATP in Example 1.

[0073] Example 5

[0074] This embodiment provides a method for preparing a lithium-rich manganese-based cathode material coated with nanofibers. The only difference from Example 1 is that in step (2), 0.8g LATP is added instead of 0.5g LATP in Example 1.

[0075] Example 6

[0076] This embodiment provides a method for preparing a lithium-rich manganese-based cathode material coated with nanofibers, including the following steps:

[0077] (1) Dissolve 1g PAN and 1g SAN in 13ml DMF solution, stir for 6h, and add 2g Ni. 0.35 Mn 0.65 (OH)2 and 0.7g lithium hydroxide were stirred for 16h to obtain the inner spinning solution;

[0078] (2) Dissolve 3g PVP in 20ml DMF solution, stir for 2h, add 0.5g LAGP, stir for 16h to obtain outer spinning solution;

[0079] (3) The inner spinning solution and the outer spinning solution are used to make a nanofiber membrane by coaxial electrospinning process. The voltage of the coaxial electrospinning process is 16kV, the feed speed is 0.2mL / h, and the receiving distance is 20cm.

[0080] (4) The nanofiber membrane was placed in an atmosphere furnace. The atmosphere of the atmosphere furnace was argon and oxygen in a volume ratio of 2:1. The temperature program was set to heat the membrane from room temperature to 220°C at a heating rate of 4°C / min and hold it for 1 hour, then heat it to 680°C at a heating rate of 4°C / min and hold it for 4 hours, then heat it to 920°C at a heating rate of 4°C / min and hold it for 12 hours, and then cool it to 650°C at a cooling rate of 1.5°C / min and hold it for 2 hours to obtain the lithium-rich manganese-based cathode material coated with nanofiber.

[0081] Example 7

[0082] This embodiment provides a method for preparing a lithium-rich manganese-based cathode material coated with nanofibers, including the following steps:

[0083] (1) Dissolve 2g PVP in 10ml DMF solution, stir for 2h, and add 2g Ni. 0.35 Mn 0.65 (OH)2 and 2g of lithium carbonate were stirred for 10h to obtain the inner spinning solution;

[0084] (2) Dissolve 2g PAN in 20ml DMF solution, stir for 6h, add 0.5g LLZO, stir for 10h to obtain outer spinning solution;

[0085] (3) The inner spinning solution and the outer spinning solution are used to make nanofiber membranes by coaxial electrospinning process. The voltage of coaxial electrospinning process is 10kV, the propulsion speed is 0.4mL / h, and the receiving distance is 16cm.

[0086] (4) The nanofiber membrane was placed in an atmosphere furnace. The atmosphere of the atmosphere furnace was argon and oxygen in a volume ratio of 3:1. The temperature program was set to heat the membrane from room temperature to 280°C at a heating rate of 2°C / min and hold it for 0.5h, then heat it to 650°C at a heating rate of 2°C / min and hold it for 6h, then heat it to 960°C at a heating rate of 2°C / min and hold it for 8h, and then cool it down to 550°C at a cooling rate of 0.5°C / min and hold it for 0.5h to obtain the lithium-rich manganese-based cathode material coated with nanofiber.

[0087] Comparative Example 1

[0088] This comparative example provides a method for preparing a lithium-rich manganese-based cathode material. The only difference from Example 1 is that in step (4), the atmosphere of the atmosphere furnace is argon instead of the atmosphere of Example 1, which is argon and oxygen in a volume ratio of 4:1.

[0089] Comparative Example 2

[0090] This comparative example provides a method for preparing a lithium-rich manganese-based cathode material. The only difference from Example 1 is that in step (4), the atmosphere of the atmosphere furnace is oxygen instead of the atmosphere of the atmosphere furnace in Example 1, which is argon and oxygen in a volume ratio of 4:1.

[0091] Comparative Example 3

[0092] This comparative example provides a method for preparing a lithium-rich manganese-based cathode material, comprising the following steps:

[0093] 2g Ni 0.35 Mn 0.65 The lithium-rich manganese-based cathode material prepared by (OH)2 and 2g of lithium acetate was mixed with 0.5g of LATP by dry method, and the temperature was increased from room temperature to 400℃ at a heating rate of 3℃ / min and held for 6h to obtain the lithium-rich manganese-based cathode material.

[0094] Comparative Example 4

[0095] This comparative example provides a method for preparing a lithium-rich manganese-based cathode material. The only difference from Example 1 is that LATP is not added in step (2).

[0096] Test Case

[0097] The performance of the lithium-rich manganese-based cathode materials prepared in the above embodiments and comparative examples was tested, as follows:

[0098] Using N-methylpyrrolidone as a dispersant, lithium-rich manganese-based cathode material, carbon black, and PVDF (polyvinylidene fluoride) were mixed at a mass ratio of 90:5:5 to prepare a cathode slurry. The cathode slurry was then uniformly coated onto carbon-coated aluminum foil with a coating density of 3 cm³. 2 / mg, dried in an oven at 80℃ for 2h to obtain a positive electrode sheet; under an argon atmosphere in a glove box, the positive electrode sheet, LATP solid electrolyte membrane, lithium indium alloy negative electrode and platinum negative electrode current collector are stacked in sequence;

[0099] The performance of the battery prepared above and the comparative lithium-rich manganese-based composite electrode were tested, as follows:

[0100] (1) 0.1C discharge specific capacity test method: At 25℃, charge the battery at 0.1C to a voltage of 4.8V, and discharge it at 0.1C to a voltage of 2.5V. Perform this test once. The results are shown in Table 1. The formula for calculating the first-efficiency rating is as follows:

[0101] First-time effect = 100% × 1 st Discharge specific capacity / 1 st Charging capacity;

[0102] (2) Rate performance test method: At 25℃, the battery was charged at 0.1C to 4.8V and discharged at 0.1C to 2.5V; the battery was charged at 0.2C to 4.8V and discharged at 0.2C to 2.5V; the battery was charged at 0.5C to 4.8V and discharged at 0.5C to 2.5V; the battery was charged at 1C to 4.8V and discharged at 1C to 2.5V. The results are shown in Table 1. The rate performance calculation formula is as follows:

[0103] Rate retention = 100% × 1C discharge specific capacity / 0.1C discharge specific capacity;

[0104] (3) Cyclic performance test method: At 25℃, the battery was charged at 0.1C to 4.8V and discharged at 0.1C to 2.5V; the battery was charged at 0.2C to 4.8V and discharged at 0.2C to 2.5V; the battery was charged at 0.5C to 4.8V and discharged at 0.5C to 2.5V; the battery was charged at 1C to 4.8V and discharged at 1C to 2.5V. The battery was charged and discharged at 1C for 50 cycles. The results are shown in Table 1. The cycle performance calculation formula is as follows:

[0105] Cyclic performance = 100% × 53 th Discharge specific capacity / 4 th Discharge specific capacity;

[0106] Table 1

[0107]

[0108]

[0109] As shown in Table 1, the battery prepared by the nanofiber-coated lithium-rich manganese-based cathode material of the present invention has excellent first-efficiency, specific capacity, rate performance and cycle performance. As can be seen from the comparison between the examples and Comparative Example 2, a large specific surface area of ​​the cathode material can increase the contact with the solid electrolyte and improve the electrical performance of the battery. However, when the specific surface area is too large, the battery will be overcharged quickly, resulting in a rapid decline in cycle performance.

[0110] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing a lithium-rich manganese-based cathode material coated with nanofibers, characterized in that, Includes the following steps: (1) The first polymer, lithium-rich manganese-based precursor, lithium salt and first solvent are mixed to prepare inner spinning solution; (2) The second polymer, solid electrolyte and second solvent are mixed to prepare the outer spinning solution; (3) Coaxial electrospinning and sintering are performed using the inner spinning solution as the inner layer and the outer spinning solution as the outer layer. The sintering atmosphere includes argon and oxygen, with a volume ratio of argon to oxygen of (2-5):1; the first polymer and the second polymer are different.

2. The preparation method according to claim 1, characterized in that, The ratio of the mass of the first polymer to the volume of the first solvent is (15-20):100, where the mass is in grams and the volume is in milliliters; and / or, The ratio of the mass of the second polymer to the volume of the second solvent is (10-15):100, where the mass is in g and the volume is in ml.

3. The preparation method according to claim 1 or 2, characterized in that, The first polymer comprises at least one of PVP, SAN, and PAN; and / or, The second polymer comprises at least one of PVP, SAN, and PAN; and / or, The solid electrolyte includes at least one of LATP, LLZO, and LAGP.

4. The preparation method according to any one of claims 1-3, characterized in that, In step (1), the mass ratio of the first polymer to the lithium-rich manganese-based precursor is 1:(0.5-2); and / or, In step (2), the mass ratio of the second polymer to the solid electrolyte is 1:(0.1-0.4).

5. The preparation method according to any one of claims 1-4, characterized in that, The specific steps of the sintering include heating sintering and cooling sintering; Preferably, the heating sintering includes a first sintering, a second sintering, and a third sintering; Preferably, the cooling sintering is performed after the heating sintering.

6. The preparation method according to claim 5, characterized in that, The heating rate for the sintering process is 2-4 °C / min; and / or, The first sintering temperature is 220-280℃; and / or, The first sintering time is 0.5-2 hours; and / or, The second sintering temperature is 650-700℃; and / or, The second sintering time is 4-6 hours; and / or, The temperature of the third sintering is 920-960℃; and / or, The third sintering time is 8-12 hours; and / or, The cooling rate of the cooling sintering is 0.5-1.5℃ / min; and / or, The cooling sintering temperature is 550-650℃; and / or, The cooling and sintering time is 0.5-2 hours.

7. The preparation method according to any one of claims 1-6, characterized in that, The lithium-rich manganese-based precursor includes at least one of nickel manganese hydroxide and nickel cobalt manganese hydroxide; and / or, The lithium salt includes at least one selected from lithium acetate, lithium hydroxide, and lithium carbonate; and / or, The molar ratio of the lithium-rich manganese-based precursor to the lithium salt is 1:(1.3-1.5); and / or, The molar ratio of nickel to manganese in the lithium-rich manganese-based precursor is (35-40):(60-65).

8. The preparation method according to any one of claims 1-7, characterized in that, The voltage for the coaxial electrospinning is 10-16 kV; and / or, The coaxial electrospinning feed rate is 0.2-0.6 mL / h; and / or, The receiving distance for the coaxial electrospinning is 16-20cm.

9. The lithium-rich manganese-based cathode material coated with nanofibers prepared by the preparation method according to any one of claims 1-8.

10. The application of the coated nanofiber lithium-rich manganese-based cathode material prepared by the preparation method according to any one of claims 1-8 in lithium-ion batteries or electrodes.

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