Copper-iron-manganese-based sodium battery positive electrode material, and preparation method and use therefor

Abstract

A copper-iron-manganese-based sodium battery positive electrode material, and a preparation method and use therefor. The preparation method comprises the following steps: mixing a copper-iron-manganese-based precursor, a sodium source, a transition metal source and a solvent, removing the solvent, and sintering, so as to obtain the copper-iron-manganese-based sodium battery positive electrode material. The preparation method can achieve doping and coating of the positive electrode material in one step, specifically, metal ions are doped into the positive electrode material, the surface of the positive electrode material is coated with a metal fast ion conductor layer, such that the cycling stability, the gas generation performance and the sodium ion conductivity of the positive electrode material are improved, and the sliding of the inner core transition metal layer is also inhibited.

Description

A copper-iron-manganese-based sodium cathode material and its preparation method and application Technical Field

[0001] The present application belongs to the field of battery technology and relates to a copper-iron-manganese-based sodium cathode material and a preparation method and application thereof. Background Art

[0002] With the rapid development of the new energy industry, lithium resources have been consumed in large quantities, leading to rising lithium prices. Therefore, high costs have limited the development of lithium-ion batteries for large-scale energy storage. Sodium and lithium have similar properties, and sodium-ion batteries have the advantages of abundant and accessible sodium resources, low cost, and high safety, making them a research hotspot in the new energy industry. However, due to the large radius of sodium ions, the structure is unstable during charge and discharge, and the sodium ions easily react with water and electrolytes, resulting in excessively high alkaline content on the surface of the positive electrode material. These problems have limited the development of sodium-ion battery materials.

[0003] Layered oxides, Prussian blue analogs, and polyanion materials are three common cathode materials used in sodium-ion batteries, among which layered oxide cathode materials have excellent comprehensive performance. Copper, iron, and manganese-based cathode materials belong to layered oxide cathode materials, which have attracted much attention due to their advantages such as wide distribution of raw materials, high air stability, and high energy density. Doping and coating of layered oxide cathode materials are effective methods to improve the electrochemical performance of sodium-ion batteries. As far as the coating method is concerned, the coating layer on the surface of the sodium-ion battery cathode material can effectively prevent sodium ions from contacting the electrolyte, thereby avoiding the problem of high alkali content on the surface of the cathode material. This not only improves the gas production stability of the cathode material, but also broadens the transmission channel of sodium ions.

[0004] For example, CN 116706041A discloses a sodium ion positive electrode material and its preparation and application. The sodium ion positive electrode material comprises a sodium ion layered oxide and a coating layer. The coating layer is a composite coating layer of TiB2 and a lanthanum molybdate solid electrolyte. The general structural formula of the lanthanum molybdate solid electrolyte is La 2-u N u Mo2O9, wherein N is selected from one or more of Ni, Bi, K, Ba, Ca, Sr, Nd, Sm, Dy, Er, and Yb, 0.03≤u≤0.1, and an electron-ion co-conducting coating layer TiB2 / La is used. 2-u N u Mo2O9-coated sodium-ion battery layered oxide positive electrode materials can effectively improve air stability while significantly improving the rate characteristics and cycle stability of sodium-ion battery layered oxide positive electrode materials. However, the coating material is expensive and cannot suppress the sliding of the internal transition metal layer.

[0005] Based on the above research, it is necessary to provide a preparation method for copper-iron-manganese-based sodium cathode materials, which can not only improve the cycle stability and gas production performance of the material by coating, but also improve the conductivity of sodium ions and inhibit the sliding of the inner core transition metal layer.

[0006] Summary of the Invention

[0007] The following is a summary of the subject matter described in detail herein. This summary is not intended to limit the scope of the claims.

[0008] The purpose of the present application is to provide a copper-iron-manganese-based sodium cathode material and its preparation method and application. The preparation method can achieve the doping and coating of the cathode material in one step. Specifically, metal ions can be doped into the interior of the cathode material and a layer of metal fast ion conductor layer can be coated on the surface of the cathode material, thereby improving the cycle stability, gas production performance, and sodium ion conductivity of the cathode material and also inhibiting the sliding of the inner core transition metal layer.

[0009] To achieve this goal, this application adopts the following technical solutions:

[0010] In a first aspect, the present application provides a method for preparing a copper-iron-manganese-based sodium cathode material, the preparation method comprising the following steps:

[0011] A copper-iron-manganese-based precursor, a sodium source, a transition metal source and a solvent are mixed, the solvent is removed, and finally sintered to obtain the copper-iron-manganese-based sodium cathode material.

[0012] The present application directly mixes the precursor of the positive electrode material with a sodium source, a transition metal source and a solvent to prepare the positive electrode material, which can cause the sodium source and the transition metal source to react, and in situ coat the surface of the copper-iron-manganese-based sodium positive electrode material with a layer of fast ion conductor obtained by the reaction of the sodium source and the transition metal source. At the same time, the transition metal ions in the coating layer can be doped into the positive electrode material during the sintering process, thereby realizing one-step doping and coating.

[0013] In addition, the present application performs wet mixing and then removes the solvent for sintering. Compared with dry mechanical mixing, this reduces the influence of the dry powder particles of the coating on the coating process, enables the precursor material to fully contact with the coating material, thereby making the coating layer more uniform and improving the structural stability of the surface layer.

[0014] In one embodiment, the transition metal source comprises a titanium source.

[0015] In one embodiment, the titanium source comprises titanium dioxide.

[0016] In one embodiment, the surface of the copper-iron-manganese-based sodium cathode material is coated with sodium titanate, and the core is doped with titanium ions.

[0017] The surface of the copper-iron-manganese-based sodium cathode material of the present application is coated with sodium titanate, which avoids contact between the internal material and the electrolyte, improves the gas production performance of the sodium ion battery, increases the transmission efficiency of sodium ions, and thereby improves the long-term cycle stability of the sodium ion battery cathode material; and during the sintering process, the titanium ions in the coating layer will be partially doped into the internal cathode material, thereby increasing the conductivity of the sodium ions and inhibiting the sliding of the transition metal layer.

[0018] This application uses a transition metal source and a titanium source because titanium ions can increase the interplanar spacing of the sodium ion layer and promote the diffusion of sodium ions in the sodium ion layer. The coating layer of sodium titanate has good ionic conductivity, which inhibits the side reaction between the active material and the electrolyte, ensures the stability of the two-phase interface, and thus improves the rate performance and cycle stability of the positive electrode material.

[0019] In one embodiment, the content of sodium titanate in the copper-iron-manganese-based sodium cathode material is 0.5-3wt%, for example, it can be 0.5wt%, 1wt%, 1.5wt%, 2wt%, 2.5wt% or 3wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0020] The content of the sodium titanate coating layer in the present application will affect the battery performance. If the sodium titanate content is too high, the thickness of the coating layer will increase, which will reduce the conductivity of the microscopic particles, which is not conducive to the electrochemical performance and accelerates the attenuation of the battery capacity. If the sodium titanate content is too low, the coating layer will easily become uneven and cannot effectively suppress the side reactions between the internal material and the electrolyte.

[0021] In one embodiment, the solvent comprises an alcohol solvent, and the alcohol solvent comprises ethanol.

[0022] In one embodiment, the method of removing the solvent includes heating and drying.

[0023] In one embodiment, the heating and drying temperature is 60-90°C, for example, 60°C, 70°C, 80°C or 90°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0024] In one embodiment, the sintering temperature is 600-1000°C, for example, 700°C, 800°C, 900°C or 1000°C, and the sintering time is 5-10h, for example, 5h, 6h, 7h, 8h or 10h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0025] In one embodiment, the particle size D50 of the copper-iron-manganese-based precursor is 4-10 μm, for example, 4 μm, 5 μm, 6 μm, 8 μm or 10 μm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0026] In one embodiment, the copper-iron-manganese-based precursor is prepared by the following method:

[0027] mixing the first solution, the second solution, the precipitant solution and the complexing agent solution to perform a coprecipitation reaction to obtain the copper-iron-manganese-based precursor;

[0028] The first solution includes an iron salt and a manganese salt, and the second solution includes a copper salt.

[0029] In one embodiment, the second solution further comprises a dispersant.

[0030] When preparing the copper-iron-manganese-based precursor, the metal salt solution is fed separately in the present application, wherein the copper salt is fed separately and the copper salt solution also includes a dispersant, thereby promoting the uniform precipitation of copper ions, iron ions and manganese ions and avoiding element segregation.

[0031] In one embodiment, the content of the dispersant is 0.05-2% by mass of the copper element in the second solution, for example, 0.05%, 0.1%, 0.3%, 0.5%, 0.8%, 1%, 1.3%, 1.5%, 1.8% or 2%, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0032] The addition of the dispersant described in the present application prevents the individual precipitation of copper ions, but the amount of the dispersant added should not be too much. If the amount added is too much, the crystallinity of the particles will deteriorate and the impurity content will increase.

[0033] In one embodiment, the dispersant includes any one or a combination of at least two of polyethylene glycol, hexadecyltrimethylammonium bromide, alkyl phosphate, disodium ethylenediaminetetraacetic acid, crown ether or amino acid, and polyethylene glycol can be selected.

[0034] In one embodiment, the copper ion concentration in the second solution is 20-50 g / L, for example, 20 g / L, 25 g / L, 30 g / L, 40 g / L or 50 g / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0035] In one embodiment, the concentration of total metal ions in the first solution is 80-120 g / L, for example, 80 g / L, 90 g / L, 100 g / L, 110 g / L or 120 g / L, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0036] In one embodiment, the feed rate of the first solution is 8-40 L / h, for example, 8 L / h, 10 L / h, 20 L / h, 30 L / h or 40 L / h, and the feed rate of the second solution is 1-10 L / h, for example, 1 L / h, 4 L / h, 6 L / h, 8 L / h or 10 L / h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0037] In one embodiment, the concentration of the precipitant solution is 30-35 wt%, for example, 31 wt%, 33 wt% or 35 wt%, and the feed rate is 1-15 L / h, for example, 2 L / h, 10 L / h or 15 L / h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0038] In one embodiment, the concentration of the complexing agent solution is 10-20wt%, for example, 11wt%, 13wt%, 15wt% or 20wt%, and the feed rate is 0.1-3L / h, for example, 0.2L / h, 0.8L / h, 1L / h or 2L / h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0039] In one embodiment, the precipitant solution comprises sodium hydroxide, and the complexing agent solution comprises aqueous ammonia and / or ammonium sulfate.

[0040] In one embodiment, the first solution, the second solution, the precipitant solution and the complexing agent solution are simultaneously introduced into the base solution to perform a co-precipitation reaction.

[0041] In one embodiment, the pH value of the base liquid is 11-12, for example, 11, 11.2, 11.5, 11.7 or 12, the ammonia concentration is 4-10 g / L, for example, 5 g / L, 8 g / L or 10 g / L, and the temperature is 40-80°C, for example, 40°C, 50°C, 60°C, 70°C or 80°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0042] In one embodiment, the pH of the coprecipitation reaction is 9-11, for example, 9, 9.5, 10, 10.5 or 11, the stirring speed is 200-500 rpm, for example, 200 rpm, 250 rpm, 300 rpm, 400 rpm or 500 rpm, and the temperature is 40-60°C, for example, 40°C, 45°C, 50°C, 55°C or 60°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0043] In one embodiment, in the coprecipitation reaction system, the ammonia concentration is 4-8 g / L, for example, it can be 4 g / L, 5 g / L, 6 g / L, 7 g / L or 8 g / L, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0044] As an optional technical solution of the preparation method described in this application, the preparation method comprises the following steps:

[0045] (1) The first solution, the second solution, the precipitant solution, and the complexing agent solution are introduced into the base solution in parallel, and a coprecipitation reaction is carried out at a temperature of 40-60° C., a stirring speed of 200-500 rpm, and a pH of 9-11 to obtain a copper-iron-manganese-based precursor having a particle size D50 of 4-10 μm;

[0046] The first solution comprises an iron salt and a manganese salt with a total metal ion concentration of 80-120 g / L, the second solution comprises a copper salt and a dispersant, the content of the dispersant is 0.05-2% of the mass of the copper element in the second solution, and the copper ion concentration in the second solution is 20-50 g / L;

[0047] The pH value of the base solution is 11-12, the ammonia concentration is 4-10 g / L, and the temperature is 40-80°C;

[0048] (2) The copper-iron-manganese-based precursor, sodium source, titanium source and alcohol solvent described in step (1) are mixed, and then heated and dried at 60-90° C. to remove the alcohol solvent, and finally sintered at 600-1000° C. for 5-10 hours to obtain the copper-iron-manganese-based sodium positive electrode material, wherein the surface of the copper-iron-manganese-based sodium positive electrode material is coated with sodium titanate, the core is doped with titanium ions, and the content of sodium titanate is 0.5-3wt%.

[0049] In a second aspect, the present application provides a copper-iron-manganese-based sodium cathode material, which is prepared using the preparation method described in the first aspect.

[0050] In a third aspect, the present application provides a sodium ion battery, which includes the copper-iron-manganese-based sodium cathode material as described in the second aspect.

[0051] Compared with the prior art, this application has the following beneficial effects:

[0052] The present application prepares the positive electrode material by directly using a precursor with a sodium source, a transition metal source and a solvent, which can make the sodium source react with the transition metal source, and in situ coat the surface of the copper-iron-manganese-based sodium positive electrode material with a layer of fast ion conductor obtained by the reaction of the sodium source and the transition metal source. At the same time, the transition metal ions in the coating layer can be doped into the positive electrode material during the sintering process, realizing one-step doping and coating, while improving the cycle stability, gas production performance and sodium ion conductivity of the copper-iron-manganese-based sodium positive electrode material and suppressing the sliding of the inner core transition metal layer.

[0053] Still other aspects will become apparent upon reading and understanding the detailed description. DETAILED DESCRIPTION

[0054] The technical solution of the present application is further described below through specific implementation methods. Those skilled in the art should understand that the embodiments are only used to help understand the present application and should not be regarded as specific limitations of the present application.

[0055] Example 1

[0056] This embodiment provides a method for preparing a copper-iron-manganese-based sodium cathode material, the preparation method comprising the following steps:

[0057] (1) mixing manganese sulfate, ferrous sulfate, and water to prepare a first solution, wherein the total metal ion concentration is 115 g / L;

[0058] A second solution was prepared by adding polyethylene glycol (1% by mass of copper element) to a 50 g / L copper sulfate solution; the molar ratio of copper ions, iron ions, and manganese ions in the first solution and the second solution was 1:1:1;

[0059] (2) Towards 1m 3 Pure water, liquid alkali and ammonia water were added to the reactor to prepare a base liquid, and N2 was introduced as a protective gas. The pH value of the base liquid was 11, the ammonia concentration was 8 g / L, and the temperature was 50°C.

[0060] (3) The first solution of step (1) is fed at a rate of 8 L / h, the second solution of step (1) is fed at a rate of 10 L / h, industrial liquid alkali is fed at a rate of 2.4 L / h, and ammonia water is fed at a rate of 0.2 L / h in parallel into the base liquid of step (2), and a coprecipitation reaction is carried out at a temperature of 50° C., a stirring speed of 350 rpm, an ammonia concentration of 3.5 g / L, and a pH of 10. The reaction is stopped when the particle size D50 reaches 8 μm, to obtain a copper-iron-manganese-based precursor with a particle size D50 of 8 μm;

[0061] The concentration of the industrial liquid caustic soda is 32wt%, and the concentration of the ammonia water is 15wt%;

[0062] (4) The copper-iron-manganese-based precursor, sodium carbonate, transition metal source and ethanol described in step (3) are mixed, and then heated and dried at 60° C. to remove the ethanol, and finally sintered at 600° C. for 8 hours to obtain the copper-iron-manganese-based sodium cathode material.

[0063] The transition metal source is titanium dioxide, the surface of the copper-iron-manganese-based sodium cathode material is coated with sodium titanate, the core is doped with titanium ions, and the content of sodium titanate is 1 wt%.

[0064] Example 2

[0065] This embodiment provides a method for preparing a copper-iron-manganese-based sodium cathode material, the preparation method comprising the following steps:

[0066] (1) mixing manganese sulfate, ferrous sulfate, and water to prepare a first solution, wherein the total metal ion concentration is 110 g / L;

[0067] A second solution was prepared by adding polyethylene glycol (1% by mass of copper element) to a 50 g / L copper sulfate solution; the molar ratio of copper ions, iron ions, and manganese ions in the first solution and the second solution was 1:1:1;

[0068] (2) Towards 1m 3 Pure water, liquid alkali and ammonia water were added to the reactor to prepare a base liquid, and N2 was introduced as a protective gas. The pH value of the base liquid was 10.5, the ammonia concentration was 5g / L, and the temperature was 50°C.

[0069] (3) The first solution of step (1) is fed at a rate of 8 L / h, the second solution of step (1) is fed at a rate of 10 L / h, industrial liquid alkali is fed at a rate of 2.3 L / h, and ammonia water is fed at a rate of 0.2 L / h in parallel into the base liquid of step (2), and a coprecipitation reaction is carried out at a temperature of 50° C., a stirring speed of 400 rpm, an ammonia concentration of 3.0 g / L, and a pH of 9.5. The reaction is stopped when the particle size D50 reaches 6 μm, to obtain a copper-iron-manganese-based precursor with a particle size D50 of 6 μm;

[0070] The concentration of the industrial liquid caustic soda is 32wt%, and the concentration of the ammonia water is 15wt%;

[0071] (4) The copper-iron-manganese-based precursor, sodium carbonate, titanium dioxide and ethanol described in step (3) are mixed, and then heated and dried at 60° C. to remove the ethanol, and finally sintered at 700° C. for 5 hours to obtain the copper-iron-manganese-based sodium positive electrode material, wherein the surface of the copper-iron-manganese-based sodium positive electrode material is coated with sodium titanate, the core is doped with titanium ions, and the content of sodium titanate is 2wt%.

[0072] Example 3

[0073] This embodiment provides a method for preparing a copper-iron-manganese-based sodium cathode material, the preparation method comprising the following steps:

[0074] (1) mixing manganese sulfate, ferrous sulfate, and water to prepare a first solution, wherein the total metal ion concentration is 110 g / L;

[0075] A second solution was prepared by adding polyethylene glycol (1% by mass of copper element) to a 40 g / L copper sulfate solution; the molar ratio of copper ions, iron ions, and manganese ions in the first solution and the second solution was 2:1:6;

[0076] (2) Towards 1m 3 Pure water, liquid alkali and ammonia water were added to the reactor to prepare a base liquid, and N2 was introduced as a protective gas. The pH value of the base liquid was 11.5, the ammonia concentration was 4 g / L, and the temperature was 50°C.

[0077] (3) the first solution of step (1) is fed at a rate of 8 L / h, the second solution of step (1) is fed at a rate of 7 L / h, industrial liquid alkali is fed at a rate of 2.6 L / h, and ammonia water is fed at a rate of 0.2 L / h in parallel into the base liquid of step (2), and a coprecipitation reaction is carried out at a temperature of 50° C., a stirring speed of 420 rpm, and a pH of 11. The reaction is stopped when the particle size D50 reaches 5 μm, to obtain a copper-iron-manganese-based precursor with a particle size D50 of 5 μm;

[0078] The concentration of the industrial liquid caustic soda is 32wt%, and the concentration of the ammonia water is 15wt%;

[0079] (4) The copper-iron-manganese-based precursor, sodium carbonate, titanium dioxide and ethanol described in step (3) are mixed, and then heated and dried at 90° C. to remove the ethanol, and finally sintered at 700° C. for 5 hours to obtain the copper-iron-manganese-based sodium positive electrode material, wherein the surface of the copper-iron-manganese-based sodium positive electrode material is coated with sodium titanate, the core is doped with titanium ions, and the content of sodium titanate is 0.5wt%.

[0080] Example 4

[0081] This embodiment provides a method for preparing a copper-iron-manganese-based sodium cathode material. The preparation method is the same as that of Example 1, except that the transition metal source in step (4) is zirconium oxide.

[0082] Example 5

[0083] This embodiment provides a method for preparing a copper-iron-manganese-based sodium cathode material. The preparation method is the same as that of Example 1, except that the transition metal source in step (4) is aluminum oxide.

[0084] Example 6

[0085] This embodiment provides a method for preparing a copper-iron-manganese-based sodium cathode material. The preparation method is the same as that of Example 1 except that the amount of raw materials added in step (4) is changed to make the content of sodium titanate 3 wt%.

[0086] Example 7

[0087] This embodiment provides a method for preparing a copper-iron-manganese-based sodium cathode material. The preparation method is the same as that of Example 1 except that the amount of raw materials added in step (4) is changed to make the content of sodium titanate 4wt%.

[0088] Example 8

[0089] This embodiment provides a method for preparing a copper-iron-manganese-based sodium cathode material. The preparation method is the same as that of Example 1, except that polyethylene glycol is not added to the second solution in step (1).

[0090] Comparative Example 1

[0091] This comparative example provides a method for preparing a copper-iron-manganese-based sodium cathode material. The preparation method is the same as Example 1 except that no transition metal source is added in step (4).

[0092] Comparative Example 2

[0093] This comparative example provides a method for preparing a copper-iron-manganese-based sodium cathode material. The preparation method is the same as Example 1 except that ethanol is not added in step (4) and the copper-iron-manganese-based precursor, sodium carbonate and transition metal source are dry-mechanically mixed.

[0094] Comparative Example 3

[0095] This comparative example provides a method for preparing a copper-iron-manganese-based sodium cathode material. The preparation method is the same as Example 1 except that step (4) first sintering the copper-iron-manganese-based precursor and sodium carbonate at 600°C for 8 hours, then mixing the obtained cathode material with a transition metal source and ethanol, heating and drying at 60°C, and sintering at 600°C for 8 hours.

[0096] The copper-iron-manganese-based sodium cathode materials obtained in the above examples and comparative examples were prepared into cathode sheets, and sodium ion batteries were prepared with sodium sheets, NaClO4 electrolyte and polyethylene separator. The electrochemical performance of the sodium ion battery was tested under the conditions of completing the first cycle of charge and discharge at 0.2C and 200 cycles of charge and discharge at 1C in the voltage range of 2-4.2V.

[0097] The test results are shown in the following table:

[0098] Table 1

[0099] From the above table we can see that:

[0100] The preparation method described in the present application can obtain a sodium cathode material with excellent electrochemical properties. It can be seen from Example 1 and Comparative Examples 1-3 that when no transition metal source is added or when the preparation method is changed, the copper-iron-manganese-based sodium cathode material with excellent electrochemical properties of the present application cannot be obtained; it can be seen from Example 1 and Examples 4-7 that the type of transition metal source and the content of the coating layer used in the present application will affect the battery performance; it can be seen from Example 1 and Example 8 that the dispersant in the second solution of the present application will affect the co-precipitation effect, thereby affecting the battery performance.

[0101] In summary, the present application provides a copper-iron-manganese-based sodium cathode material and its preparation method and application. The preparation method can simultaneously achieve the doping and coating of the cathode material in one step. Specifically, metal ions are doped into the interior of the cathode material, and a layer of metal fast ion conductor layer is coated on the surface of the cathode material, thereby improving the cycle stability, gas production performance, and sodium ion conductivity of the cathode material and also inhibiting the sliding of the inner core transition metal layer.

[0102] The above description is only a specific implementation method of the present application, but the protection scope of the present application is not limited thereto. Those skilled in the art should understand that any changes or replacements that can be easily thought of by those skilled in the art within the technical scope disclosed in the present application fall within the protection scope and disclosure scope of the present application.

Claims

1. A preparation method of a copper-iron-manganese-based sodium-ion battery cathode material, comprising the following steps: Mix a copper-iron-manganese-based precursor, a sodium source, a transition metal source, and a solvent, then remove the solvent, and finally perform sintering to obtain the copper-iron-manganese-based sodium-ion battery cathode material.

2. The preparation method according to claim 1, wherein, the transition metal source includes a titanium source; optionally, the titanium source includes titanium dioxide; optionally, the surface of the copper-iron-manganese-based sodium-ion battery cathode material is coated with sodium titanate, and the core is doped with titanium ions; optionally, in the copper-iron-manganese-based sodium-ion battery cathode material, the content of sodium titanate is 0.5-3 wt%.

3. The preparation method according to claim 1 or 2, wherein, the solvent includes an alcohol solvent; optionally, the method for removing the solvent includes heating and drying; optionally, the temperature of the heating and drying is 60-90 °C; optionally, the sintering temperature is 600-1000 °C, and the time is 5-10 h; optionally, the particle size D50 of the copper-iron-manganese-based precursor is 4-10 μm.

4. The preparation method according to any one of claims 1-3, wherein, the copper-iron-manganese-based precursor is prepared by the following method: Mix a first solution, a second solution, a precipitant solution, and a complexing agent solution, and perform a coprecipitation reaction to obtain the copper-iron-manganese-based precursor; the first solution includes an iron salt and a manganese salt, and the second solution includes a copper salt.

5. The preparation method according to claim 4, wherein, the second solution further includes a dispersant; optionally, the content of the dispersant is 0.05-2% of the mass of copper element in the second solution; optionally, the dispersant includes any one or a combination of at least two of polyethylene glycol, cetyltrimethylammonium bromide, alkyl phosphate salt, disodium ethylenediaminetetraacetate, crown ether, or amino acid, and further optionally polyethylene glycol.

6. The preparation method according to claim 4 or 5, wherein, in the second solution, the copper ion concentration is 20-50 g / L; optionally, in the first solution, the total metal ion concentration is 80-120 g / L; optionally, the feeding rate of the first solution is 8-40 L / h, and the feeding rate of the second solution is 1-10 L / h; optionally, the concentration of the precipitant solution is 30-35 wt%, and the feeding rate is 1-15 L / h; optionally, the concentration of the complexing agent solution is 10-20 wt%, and the feeding rate is 0.1-3 L / h.

7. The preparation method according to any one of claims 4-6, wherein, the first solution, the second solution, the precipitant solution, and the complexing agent solution are fed into the bottom liquid in parallel to perform a coprecipitation reaction; optionally, the pH value of the bottom liquid is 11-12, the ammonia concentration is 4-10 g / L, and the temperature is 40-80 °C; optionally, the pH of the coprecipitation reaction is 9-11, the stirring speed is 200-500 rpm, and the temperature is 40-60 °C.

8. The preparation method according to any one of claims 1-7, wherein, the preparation method includes the following steps: (1) The first solution, the second solution, the precipitant solution and the complexing agent solution are introduced into the bottom solution in parallel flow, and a coprecipitation reaction is carried out at a temperature of 40 - 60 °C, a stirring speed of 200 - 500 rpm and a pH of 9 - 11 to obtain a copper-iron-manganese-based precursor with a D50 particle size of 4 - 10 μm; The first solution includes iron salts and manganese salts with a total metal ion concentration of 80 - 120 g / L, the second solution includes copper salts and a dispersant, the content of the dispersant is 0.05 - 2% of the mass of copper element in the second solution, and in the second solution, the copper ion concentration is 20 - 50 g / L; The pH value of the bottom solution is 11 - 12, the ammonia concentration is 4 - 10 g / L, and the temperature is 40 - 80 °C; (2) The copper-iron-manganese-based precursor, sodium source, titanium source and alcohol solvent described in step (1) are mixed, then heated and dried at 60 - 90 °C to remove the alcohol solvent, and finally sintered at a temperature of 600 - 1000 °C for 5 - 10 h, to obtain the copper-iron-manganese-based sodium-ion battery positive electrode material. The surface of the copper-iron-manganese-based sodium-ion battery positive electrode material is coated with sodium titanate, and the core is doped with titanium ions. The content of sodium titanate is 0.5 - 3 wt%.

9. A copper-iron-manganese-based sodium-ion battery positive electrode material prepared by the preparation method according to any one of claims 1 - 8.

10. A sodium-ion battery comprising the copper-iron-manganese-based sodium-ion battery positive electrode material according to claim 9.

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