Spinel-structure nickel-manganese positive electrode material, preparation method and application thereof

Abstract

The application relates to a spinel structure nickel-manganese positive electrode material and a preparation method and application thereof. The preparation method comprises the following steps: preparing a nickel salt and a manganese salt into solutions respectively, mixing the solutions, adding a first metal element salt into the mixed solution, carrying out a coprecipitation reaction to prepare a first metal element pre-doped precursor, uniformly mixing the first metal element pre-doped precursor, a lithium source, a second metal element salt and a fluorine source, carrying out first calcination to obtain a first calcined product, mixing the first calcined product with the first metal element salt, carrying out second calcination to obtain a second calcined product, mixing the second calcined product with the fluorine source, carrying out heat treatment, crushing and sieving to obtain the spinel structure nickel-manganese positive electrode material. In step S2, the second calcination comprises the following steps: carrying out calcination under an oxygen atmosphere at 750-950 DEG C for 10-15 h; and the temperature rising speed of the second calcination is 2-5 DEG C / min. The application constructs a component gradient change and a stable surface protective layer, and greatly improves the cycle stability of the positive electrode material.

Description

Technical Field

[0001] This invention relates to the field of cathode materials, specifically to a spinel-structured nickel-manganese cathode material, its preparation method, and its applications. Background Technology

[0002] Currently, the modification of spinel-structured nickel-manganese cathode materials mainly focuses on the following two aspects: First, while traditional surface coating techniques (such as Al2O3 and ZrO2 coating) can physically prevent direct contact between the electrode material and the electrolyte, the introduced inert coating layer significantly hinders lithium-ion interfacial transport, leading to increased internal resistance and decreased rate performance. Furthermore, the weak bonding between the coating layer and the substrate makes it prone to peeling failure during long-term cycling. Second, while conventional bulk uniform doping techniques (such as Mg and Al doping) can improve the structural stability of the bulk material, they cannot effectively address the side reactions between the material surface and the electrolyte under high voltage (>4.5V). Their effectiveness in suppressing transition metal dissolution and surface rock salt phase impurities is limited, resulting in poor battery cycle stability. Summary of the Invention

[0003] This invention provides a spinel-structured nickel-manganese cathode material, its preparation method, and its application, in order to solve the problem of poor cycle stability of cathode materials in the prior art.

[0004] In a first aspect, the present invention provides a method for preparing a spinel-structured nickel-manganese cathode material, comprising the following steps: S1. After preparing solutions of nickel salt and manganese salt separately, they are mixed. Then, the first metal element salt is added to the mixed solution to produce a co-precipitation reaction, thus obtaining the first metal element pre-doped precursor. S2. After uniformly mixing the first metal element pre-doped precursor, lithium source, second metal element salt and fluorine source, the first calcination is carried out to obtain a first calcined product. The first calcined product is mixed with the first metal element salt and carried out a second calcination to obtain a second calcined product. S3. After mixing the calcined product with a fluorine source, heat-treat the mixture, crush and sieve it to obtain spinel structure nickel-manganese cathode material. In step S2, the second calcination includes calcination at 750-950°C for 10-15 hours in an oxygen atmosphere; The heating rate for the second calcination is 2-5℃ / min.

[0005] In one optional embodiment, the first metallic element includes at least one of tungsten, molybdenum, and lanthanum. The second metallic element includes at least one of magnesium, tungsten, zinc, aluminum, and lanthanum, and the second metallic element is different from the first metallic element.

[0006] In one optional embodiment, in step S1, the reaction temperature of the coprecipitation reaction is 50-70°C, and the reaction time is 8-12 hours. The doping amount of the first metal element salt is 2500-3500ppm.

[0007] In one optional embodiment, the first calcination is a segmented calcination; The segmented calcination includes pre-calcining the mixture at 450-550°C for 2-4 hours, followed by calcination at 650-850°C for 6-10 hours.

[0008] The second calcination includes calcination at 750-950℃ for 10-15 hours in an oxygen atmosphere; The heating rate for the second calcination is 2-5℃ / min; By controlling the heating rate and holding time, high-valence elements are encouraged to diffuse to the particle surface, forming a concentration gradient distribution from the bulk phase to the surface.

[0009] In one optional embodiment, the molar ratio of the pre-doped precursor to the lithium source in the first calcination is 1:1.03-1.07; The doping amount of the second metallic element salt in the first calcination is 1500-2500 ppm; The doping amount of fluorine source in the first calcination is 500-1500 ppm.

[0010] In one optional embodiment, the doping amount of the first metal element salt in the second calcination is 1500-2500 ppm.

[0011] In one optional embodiment, in step S3, the doping amount of the fluorine source is 1500-2500 ppm; The heat treatment atmosphere is an oxygen atmosphere, the heat treatment temperature is 400-600℃, and the heat treatment time is 5-7h. Preferably, the heating rate of the heat treatment is 1-3℃ / min; By controlling the heating rate to 1-3℃ / min, a stable rock salt phase protective layer rich in high-electro-valence elements is formed on the surface of the material within a range of 1-5nm, while simultaneously achieving a uniform distribution of F element.

[0012] Secondly, the present invention provides a spinel-structured nickel-manganese cathode material prepared by the preparation method described above.

[0013] Thirdly, the present invention provides an application of the spinel structure nickel-manganese cathode material described above or the spinel structure nickel-manganese cathode material prepared by the preparation method described above in a battery.

[0014] The technical solution of this invention has the following advantages: 1. The present invention provides a method for preparing a spinel-structured nickel-manganese cathode material, comprising the following steps: S1. Nickel salt and manganese salt are separately prepared into solutions and then mixed. A first metal element salt is added to the mixed solution to undergo a co-precipitation reaction, thus obtaining a first metal element pre-doped precursor. S2. The first metal element pre-doped precursor, lithium source, second metal element salt, and fluorine source are mixed evenly and then calcined for the first time to obtain a first-calcined product. The first-calcined product is mixed with the first metal element salt and calcined for the second time to obtain a second-calcined product. S3. The second-calcined product is mixed with the fluorine source and then heat-treated, pulverized, and sieved to obtain a spinel-structured nickel-manganese cathode material. In step S2, the second calcination includes calcination at 750-950℃ for 10-15 hours in an oxygen atmosphere; the heating rate for the second calcination is 2-5℃ / min.

[0015] This invention provides a method for preparing a spinel-structured nickel-manganese cathode material. By optimizing the preparation process, setting the doping sequence, and adjusting the sintering regime, a stable surface protective layer with varying compositional gradients is constructed, enabling high-valence ions (W... 6 + Mo 6+ (etc.) are enriched on the material surface, and the surface-enriched doped ions preferentially occupy transition metal sites, suppressing Ni 2+ The migration and formation of rock salt phase impurities; in addition, through F - Partially replaces O 2- Reduce oxygen vacancy concentration and inhibit Mn during the cycle. 3+ The Jahn-Teller effect significantly reduces the degree of side reactions between the electrode and electrolyte under high temperature and high pressure conditions, thereby greatly improving the cycle stability of the cathode material.

[0016] 2. The present invention provides a method for preparing a spinel-structured nickel-manganese cathode material. The method involves mixing a precursor with a lithium source, a second metal doping source, and a fluorine source, followed by a first calcination to obtain a primary product with a basic spinel structure. The primary product and a first metal element salt are then mixed evenly and subjected to a second calcination. By controlling the heating rate to 2-5℃ / min and the holding time to 10-15h, the first metal element is promoted to extend to the surface of the cathode material, forming a concentration gradient distribution from the bulk phase to the surface. Detailed Implementation

[0017] The following embodiments are provided to better understand the present invention, but the following embodiments 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 scope of protection of the present invention.

[0018] Unless otherwise specified, all experimental steps or conditions in the examples were performed according to conventional experimental procedures and conditions in the art. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0019] To address the problem of poor cycle stability of cathode materials in existing technologies, this invention provides the following technical solution: This invention provides a method for preparing a spinel-structured nickel-manganese cathode material, comprising the following steps: S1. After preparing solutions of nickel salt and manganese salt separately, they are mixed. Then, the first metal element salt is added to the mixed solution to produce a co-precipitation reaction, thus obtaining the first metal element pre-doped precursor. S2. After uniformly mixing the first metal element pre-doped precursor, lithium source, second metal element salt and fluorine source, the first calcination is carried out to obtain a first calcined product. The first calcined product is mixed with the first metal element salt and carried out a second calcination to obtain a second calcined product. S3. After mixing the calcined product with a fluorine source, heat-treat the mixture, crush and sieve it to obtain spinel structure nickel-manganese cathode material. In step S2, the second calcination includes calcination at 750-950°C for 10-15 hours in an oxygen atmosphere; The heating rate for the second calcination is 2-5℃ / min.

[0020] In some embodiments of the present invention, the first metal element includes at least one of tungsten, molybdenum, and lanthanum. The second metallic element includes at least one of magnesium, tungsten, zinc, aluminum, and lanthanum, and the second metallic element is different from the first metallic element.

[0021] In some embodiments of the present invention, in step S1, the reaction temperature of the coprecipitation reaction is 50-70°C and the reaction time is 8-12h; The doping amount of the first metal element salt is 2500-3500ppm.

[0022] In some embodiments of the present invention, the first calcination is a segmented calcination; The segmented calcination includes pre-calcining the mixture at 450-550°C for 2-4 hours, followed by calcination at 650-850°C for 6-10 hours.

[0023] The second calcination includes calcination at 750-950℃ for 10-15 hours in an oxygen atmosphere; The heating rate for the second calcination is 2-5℃ / min.

[0024] In some embodiments of the present invention, the molar ratio of the pre-doped precursor to the lithium source in the first calcination is 1:1.03-1.07; The doping amount of the second metallic element salt in the first calcination is 1500-2500 ppm; The doping amount of fluorine source in the first calcination is 500-1500 ppm.

[0025] In some embodiments of the present invention, the doping amount of the first metal element salt in the second calcination is 1500-2500 ppm.

[0026] In some embodiments of the present invention, in step S3, the doping amount of the fluorine source is 1500-2500 ppm; The heat treatment atmosphere is an oxygen atmosphere, the heat treatment temperature is 400-600℃, and the heat treatment time is 5-7h. Preferably, the heating rate of the heat treatment is 1-3℃ / min.

[0027] The following is a specific implementation example of a spinel-structured nickel-manganese cathode material and its preparation method provided by the present invention.

[0028] Example 1 This embodiment provides a spinel-structured nickel-manganese cathode material and its preparation method, including the following steps: S1. Prepare NiSO4 solution and MnSO4 solution with a concentration of 1.5 mol / L respectively. Mix the two solutions with a Ni:Mn molar ratio of 0.5:1.5. Add (NH4) to the mixed solution. 10 W 12 O 41 ·5H2O was used to make the doping amount of W element 3000 ppm, and then a co-precipitation reaction was carried out at pH=10.8 and temperature of 60℃ for 10 h to obtain the W element doped precursor. S2. The W-doped precursor obtained in step S1 is mixed with LiOH·H2O at a molar ratio of Li:(Ni+Mn) of 1.05:1. At the same time, appropriate amounts of Mg(OH)2 and LiF are added and mixed evenly to make the Mg doping amount 1000ppm and the F doping amount 1000ppm. The mixture is subjected to gradient sintering, including pre-calcination at 500℃ for 3h and then calcination at 750℃ for 8h. The product obtained after gradient sintering is crushed to obtain a calcined product. S3. Mix the first calcined product with H2WO4 to achieve an additional doping amount of W element of 2000ppm. Calcinate the mixture at 900℃ in an oxygen atmosphere with a heating rate of 3℃ / min and a calcination time of 12h to obtain the second calcined product. By controlling the heating rate and holding time, high-valence elements are encouraged to diffuse to the particle surface, forming a concentration gradient distribution from the bulk phase to the surface. S4. The di-calcined product is mixed with LiF to achieve an additional F element doping amount of 2000 ppm and a total F element doping amount of 3000 ppm. The mixture is then heat-treated at 500℃ in an oxygen atmosphere for 6 hours at a heating rate of 2℃ / min. The heat-treated product is then pulverized and sieved to obtain a spinel structured nickel-manganese cathode material. This process controls the heating rate to promote the formation of a stable rock salt phase protective layer rich in high-valence elements on the surface of the material, while simultaneously achieving a uniform distribution of F element, ultimately obtaining a nickel-manganese spinel cathode material with a gradient composition distribution and a special surface structure.

[0029] Example 2 This embodiment provides a spinel-structured nickel-manganese cathode material and its preparation method, including the following steps: S1. Prepare NiSO4 solution with a concentration of 1.5 mol / L and MnSO4 solution with a concentration of 1.5 mol / L respectively. Mix the two solutions at a Ni:Mn molar ratio of 0.5:1.5. Add MoO2SO4 to the mixed solution to make the Mo doping amount 3000 ppm. Then carry out a co-precipitation reaction at pH=10.8 and temperature of 60℃ for 10 h to obtain the Mo doped precursor. S2. The Mo element-doped precursor obtained in step S1 is mixed with LiOH·H2O at a molar ratio of Li:(Ni+Mn) of 1.05:1. At the same time, appropriate amounts of ZnO and LiF are added and mixed evenly to make the Zn element doping amount 1000ppm and the F element doping amount 1000ppm. The mixture is subjected to gradient sintering, including pre-calcination at 500℃ for 3h and then calcination at 750℃ for 8h. The product obtained after gradient sintering is crushed to obtain a calcined product. S3. Mix one calcined product with (NH4)6Mo7O 24 The mixture was mixed to achieve an additional doping amount of 2000 ppm of W element. The mixture was then calcined at 900 °C in an oxygen atmosphere with a heating rate of 3 °C / min and a calcination time of 12 h to obtain a second-calcined product. S4. Mix the di-calcined product with LiF to make the additional doping amount of F element 2000ppm and the total doping amount of F element 3000ppm. Heat treat the mixture at 500℃ in an oxygen atmosphere for 6h. The heating rate of the heat treatment is 2℃ / min. The product obtained after heat treatment is crushed and sieved to obtain spinel structure nickel manganese cathode material.

[0030] Example 3 This embodiment provides a spinel-structured nickel-manganese cathode material and its preparation method, including the following steps: S1. Prepare NiSO4 solution with a concentration of 1.5 mol / L and MnSO4 solution with a concentration of 1.5 mol / L respectively. Mix the two solutions at a Ni:Mn molar ratio of 0.5:1.5. Add La(NO3)3 to the mixed solution to make the La doping amount 3000 ppm. Then carry out a co-precipitation reaction at pH=10.8 and temperature of 60℃ for 10 h to obtain the La doped precursor. S2. The La-doped precursor obtained in step S1 is mixed with LiOH·H2O at a molar ratio of Li:(Ni+Mn) of 1.05:1. At the same time, an appropriate amount of Al(OH)3 and LiF are added and mixed evenly to make the Al doping amount 1000ppm and the F doping amount 1000ppm. The mixture is subjected to gradient sintering, including pre-calcination at 500℃ for 3h and then calcination at 750℃ for 8h. The product obtained after gradient sintering is crushed to obtain a calcined product. S3. Mix the first calcined product with La2O3 to make the additional doping amount of La element 2000ppm. Calcinate the mixture at 880℃ in an oxygen atmosphere with a heating rate of 3℃ / min and a calcination time of 13h to obtain the second calcined product. S4. Mix the di-calcined product with LiF to make the additional doping amount of F element 2000ppm and the total doping amount of F element 3000ppm. Heat treat the mixture at 500℃ in an oxygen atmosphere for 6h. The heating rate of the heat treatment is 2℃ / min. The product obtained after heat treatment is crushed and sieved to obtain spinel structure nickel manganese cathode material.

[0031] Example 4 This embodiment provides a spinel-structured nickel-manganese cathode material and its preparation method, including the following steps: S1. Prepare NiSO4 solution and MnSO4 solution with a concentration of 1.5 mol / L respectively. Mix the two solutions with a Ni:Mn molar ratio of 0.5:1.5. Add (NH4) to the mixed solution. 10 W12 O 41 ·5H2O and MoO2SO4 were used to make the doping amount of W element 2000 ppm and the doping amount of Mo element 1000 ppm. Then, a co-precipitation reaction was carried out at pH=10.8 and temperature of 60℃ for 10 h to obtain the La element-doped precursor. S2. The W and Mo co-doped precursors obtained in step S1 are mixed with LiOH·H2O at a molar ratio of Li:(Ni+Mn) of 1.05:1. At the same time, appropriate amounts of Mg(OH)2 and ZnO are added and mixed evenly to make the Mg doping amount 1000ppm and the Zn doping amount 1000ppm. The mixture is subjected to gradient sintering, including pre-calcination at 500℃ for 3h and then calcination at 750℃ for 8h. The product obtained after gradient sintering is crushed to obtain a calcined product. S3, Mix one burnt product with (NH4) 10 W 12 O 41 • Mix 5H2O and MoO2SO4 to make the additional doping amount of W element 1000ppm and the additional doping amount of Mo element 1000ppm. Calcinate the mixture at 880℃ in an oxygen atmosphere with a heating rate of 3℃ / min and a calcination time of 13h to obtain the second calcined product. S4. Mix the di-calcined product with LiF to make the additional doping amount of F element 2000ppm and the total doping amount of F element 3000ppm. Heat treat the mixture at 500℃ in an oxygen atmosphere for 6h. The heating rate of the heat treatment is 2℃ / min. The product obtained after heat treatment is crushed and sieved to obtain spinel structure nickel manganese cathode material.

[0032] Example 5 This embodiment provides a spinel-structured nickel-manganese cathode material and its preparation method, including the following steps: S1. Prepare NiSO4 solution and MnSO4 solution with a concentration of 1.5 mol / L respectively. Mix the two solutions with a Ni:Mn molar ratio of 0.5:1.5. Add H2WO4 and La(NO3)3 to the mixed solution to make the doping amount of W 2000 ppm and the doping amount of La 1000 ppm. Then carry out a co-precipitation reaction at pH=10.8 and temperature of 60℃ for 10 h to obtain the La-doped precursor. S2. The W and La co-doped precursors obtained in step S1 are mixed with LiOH·H2O at a molar ratio of Li:(Ni+Mn) of 1.05:1. At the same time, appropriate amounts of Al(OH)3 and ZnO are added and mixed evenly to make the Al doping amount 1000ppm and the Zn doping amount 1000ppm. The mixture is subjected to gradient sintering, including pre-calcination at 500℃ for 3h and then calcination at 750℃ for 8h. The product obtained after gradient sintering is crushed to obtain a calcined product. S3. Mix the first calcined product with H2WO4 and La(NO3)3 to make the additional doping amount of W element 1000ppm and the additional doping amount of La element 1000ppm. Calcinate the mixture at 890℃ in an oxygen atmosphere with a heating rate of 3℃ / min and a calcination time of 12.5h to obtain the second calcined product. S4. Mix the di-calcined product with LiF to make the additional doping amount of F element 2000ppm and the total doping amount of F element 3000ppm. Heat treat the mixture at 500℃ in an oxygen atmosphere for 6h. The heating rate of the heat treatment is 2℃ / min. The product obtained after heat treatment is crushed and sieved to obtain spinel structure nickel manganese cathode material.

[0033] Comparative Example 1 This comparative example provides a spinel-structured nickel-manganese cathode material and its preparation method. It uses the same raw materials, doping elements, and total doping amount as Example 1. The difference lies in that the raw materials and all doping elements are mixed and then calcined in one step. The method includes the following steps: S1. Prepare NiSO4 solution with a concentration of 1.5 mol / L and MnSO4 solution with a concentration of 1.5 mol / L respectively. Mix the two solutions according to the molar ratio of Ni to Mn elements of 0.5:1.5. Then carry out a co-precipitation reaction at pH=10.8 and temperature of 60℃ for 10 h to obtain nickel-manganese cathode material precursor. S2. The cathode material precursor obtained in step S1 is mixed with LiOH·H2O at a molar ratio of Li:(Ni+Mn) of 1.05:1. At the same time, appropriate amounts of H2WO4, Mg(OH)2 and LiF are added and mixed evenly to make the doping amount of W element 5000ppm, Mg element 1000ppm and F element 3000ppm. The mixture is calcined at 900℃ for 15h to obtain a uniformly doped spinel structure nickel-manganese cathode material.

[0034] Comparative Example 2 This comparative example provides a nickel-manganese cathode material and its preparation method, including the following steps: S1. Prepare NiSO4 solution with a concentration of 1.5 mol / L and MnSO4 solution with a concentration of 1.5 mol / L respectively. Mix the two solutions according to the molar ratio of Ni to Mn elements of 0.5:1.5. Then carry out a co-precipitation reaction at pH=10.8 and temperature of 60℃ for 10 h to obtain nickel-manganese cathode material precursor. S2. The cathode material precursor obtained in step S1 is calcined at 900°C for 15 hours to obtain a nickel-manganese cathode material without doped elements.

[0035] Experimental Example 1 The electrochemical performance of the cathode materials prepared in Examples 1-5 and Comparative Examples 1-2 of this invention was tested using the following methods: The specific method for assembling the positive electrode material into a button cell is as follows: The battery was assembled in an argon atmosphere within a glove box using a Celgard 2500 separator, a lithium metal sheet as the negative electrode, and lithium hexafluorophosphate electrolyte. The battery was assembled in the following order: negative electrode, electrolyte, separator, electrolyte, and positive electrode.

[0036] Charge-discharge tests were conducted within the 3.0-4.4V voltage range. The test conditions were as follows: at 25℃, the system was first activated twice at 0.1C and 0.5C, and then cycled 100 times at 1.0C. The test results are shown in the table below.

[0037] Table 1:

[0038] The initial discharge capacity of Examples 1-5 was generally higher than that of Comparative Examples 1 and 2, especially Example 4 (133.1 mAh / g), which showed the best performance. This indicates that gradient doping and surface modulation help improve lithium-ion insertion / extraction efficiency and reduce irreversible capacity loss. In terms of initial coulombic efficiency, the examples generally reached over 94%, which was significantly better than Comparative Example 2 (91.6%), indicating that F doping and surface rock salt phase modulation effectively suppressed electrolyte decomposition and interfacial side reactions.

[0039] The retention rate after 100 cycles is the most prominent advantage of this invention. Examples 1-5 all maintained a retention rate above 95%, with Examples 4 and 5 reaching 96.5% and 96.3% respectively, significantly higher than Comparative Example 1 (88.4%) and Comparative Example 2 (76.2%). This demonstrates that by constructing a high valence ion concentration gradient and a surface rock salt phase protective layer, Ni²⁺ ions were effectively suppressed. + Migration, Mn³ + The Jahn-Teller effect and electrolyte erosion significantly improve the high-temperature and high-pressure cycling stability of the material.

[0040] Although Comparative Example 1 (uniform doping) improved stability to some extent through doping, its cycle retention rate was still significantly lower than that of the Example 1 due to the lack of gradient structure and surface modulation, indicating that "uniform doping" cannot solve the interface problem. Comparative Example 2 (undoped) showed the worst cycle performance, verifying the necessity of doping and surface modulation.

[0041] 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 spinel-structured nickel-manganese cathode material, characterized in that, Includes the following steps: S1. After preparing solutions of nickel salt and manganese salt separately, they are mixed. Then, the first metal element salt is added to the mixed solution to produce a co-precipitation reaction, thus obtaining the first metal element pre-doped precursor. S2. After uniformly mixing the first metal element pre-doped precursor, lithium source, second metal element salt and fluorine source, the first calcination is carried out to obtain a first calcined product. The first calcined product is mixed with the first metal element salt and carried out a second calcination to obtain a second calcined product. S3. After mixing the calcined product with a fluorine source, heat-treat the mixture, crush and sieve it to obtain spinel structure nickel-manganese cathode material. In step S2, the second calcination includes calcination at 750-950°C for 10-15 hours in an oxygen atmosphere; The heating rate for the second calcination is 2-5℃ / min.

2. The preparation method according to claim 1, characterized in that, The first metal element salt includes at least one of tungsten salt, molybdenum salt, and lanthanum salt; And / or, the second metal element salt includes at least one of magnesium salt, tungsten salt, zinc salt, aluminum salt, and lanthanum salt, and the second metal element salt is different from the first metal element salt.

3. The preparation method according to claim 1, characterized in that, In step S1, the reaction temperature of the coprecipitation reaction is 50-70℃, and the reaction time is 8-12h. And / or, the doping amount of the first metal element salt is 2500-3500ppm.

4. The preparation method according to claim 1, characterized in that, The first calcination is a staged calcination; The segmented calcination includes pre-calcining the mixture at 450-550°C for 2-4 hours, followed by calcination at 650-850°C for 6-10 hours.

5. The preparation method according to claim 1, characterized in that, In the first calcination, the molar ratio of the first metal element pre-doped precursor to the lithium source is 1:1.03-1.07; The doping amount of the second metallic element salt in the first calcination is 1500-2500 ppm; The doping amount of fluorine source in the first calcination is 500-1500 ppm.

6. The preparation method according to claim 1, characterized in that, The doping amount of the first metallic element salt in the second calcination is 1500-2500 ppm.

7. The preparation method according to claim 1, characterized in that, In step S3, the doping amount of the fluorine source is 1500-2500 ppm; The heat treatment is performed in an oxygen atmosphere, at a temperature of 400-600℃, and for a duration of 5-7 hours.

8. The preparation method according to claim 1, characterized in that, The heating rate of the heat treatment is 1-3℃ / min.

9. A spinel-structured nickel-manganese cathode material, characterized in that, The spinel-structured nickel-manganese cathode material was prepared by the method described in any one of claims 1-8.

10. The application of a spinel-structured nickel-manganese cathode material as described in claim 9 in a battery.

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