Titanium-zirconium double-layer coated nickel-copper-iron-manganese-sodium ion battery precursor material and preparation method and application thereof

Abstract

The application discloses a titanium-zirconium double-layer coated nickel-copper-iron-manganese sodium ion precursor material and a preparation method and application thereof. The preparation method of the material comprises the following steps: preparing a Ni x Cu y Fe z Mn 1‑x‑y‑z (OH)2 precursor; preparing an outer layer coated zirconium precursor; and preparing an outer layer re-coated titanium precursor Ni x Cu y Fe z Mn 1‑x‑y‑z Zr a Ti b (OH)2. The zirconium-titanium double-layer coated nickel-copper-iron-manganese-based precursor is uniformly mixed with sodium carbonate and calcined into a sodium ion layered positive electrode material. In the application, two layers of metal elements are uniformly coated on the surface of the nickel-copper-iron-manganese-based precursor, the middle layer zirconium migrates and dopes to the inside in the sintering process, the crystal lattice is stabilized, the outermost layer titanium effectively prevents the side reaction between the internal positive electrode material and the electrolyte in the charging and discharging process. The large-particle polycrystal sodium electrode prepared by the method has better cycle stability.

Description

Technical Field

[0001] This invention belongs to the field of sodium-ion battery cathode material precursor preparation technology, specifically relating to titanium-zirconium double-layer coated nickel-copper-iron-manganese sodium-ion battery precursor materials, their preparation methods and applications. Background Technology

[0002] With the continuous development of sodium-ion battery technology, the performance of sodium-ion batteries has been continuously improved and the cost has been continuously reduced. Sodium-ion batteries have become a new type of rechargeable battery with broad application prospects. They have broad application prospects in the fields of new energy, smart grids, and electric vehicles.

[0003] Sodium-ion battery precursor materials refer to the raw materials used to prepare the cathode material of sodium-ion batteries. The cathode material is one of the core components of sodium-ion batteries, and its performance determines key indicators such as capacity, operating voltage, and cycle life. Therefore, the research and application of sodium-ion battery precursor materials are an important foundation for the development of sodium-ion battery technology.

[0004] Currently, research on sodium electrode precursor materials mainly focuses on several categories, including layered oxides, Prussian blue and its derivatives, and polyanions. Among these, layered oxide sodium electrode precursor materials have attracted much attention due to their advantages of high capacity and high operating voltage platform. Nickel-copper-iron-manganese based cathode materials are relatively inexpensive among layered oxides and have high energy density, and are also widely studied.

[0005] With the continuous development of sodium-ion battery technology, the research and application of sodium-ion battery precursor materials has become one of the important research directions in the field of sodium-ion batteries. Improving the structural stability and cycle performance of sodium-ion battery precursor materials, reducing electrolyte corrosion of cathode materials, and mitigating gas buildup are important research topics in sodium-ion battery precursor materials. Summary of the Invention

[0006] Based on the problems existing in the prior art, this invention proposes a method for preparing a titanium-zirconium double-layer coated nickel-copper-iron-manganese-sodium ion battery precursor material.

[0007] The preparation method of the titanium-zirconium double-layer coated nickel-copper-iron-manganese-sodium ion battery precursor material provided by the present invention includes the following steps:

[0008] a) Prepare a mixed metal salt solution A by mixing nickel, copper, iron, and manganese sources in a molar ratio of x:y:z:1-xyz and purging with nitrogen gas; simultaneously prepare an ammonia solution and an alkaline solution; wherein 0.2≤x≤0.5, 0.05≤y≤0.2, 0.2≤z≤0.4.

[0009] b) Add the mixed metal salt solution A, ammonia solution, and alkaline solution prepared in step a) into the reactor and stir until the particle size reaches 10 ± 0.5 μm, then stop the reaction to obtain Ni. x Cu y Fe z Mn 1-x-y-z (OH)2 precursor;

[0010] c) Prepare zirconium salt solution, ammonia solution and alkaline solution, and add the zirconium salt solution, ammonia solution and alkaline solution to the reaction vessel of step 2) for co-precipitation and continue stirring to obtain zirconium-coated precursor;

[0011] d) Prepare a titanium salt solution, an ammonia solution, and an alkaline solution. Add these solutions to the reaction vessel from step 3) for co-precipitation and continue stirring to obtain zirconium-titanium double-coated Ni. x Cu y Fe z Mn 1-x-y-z Zr a Ti b (OH)2, where 0.2≤x≤0.5, 0.05≤y≤0.2, 0.2≤z≤0.4, 0.01≤a≤0.1, and 0.01≤b≤0.1.

[0012] In step a) of the above method, the nickel source is selected from at least one of the following: nickel sulfate, nickel nitrate or nickel chloride; the copper source is copper sulfate, copper nitrate and copper chloride; the iron source is ferrous sulfate and / or ferrous chloride; and the manganese source is selected from at least one of the following: manganese sulfate, manganese nitrate and manganese chloride.

[0013] In step a) of the above method, the alkaline solution can be a sodium hydroxide solution or a sodium carbonate solution.

[0014] In step a) of the above method, the concentration of the mixed metal salt solution A is 1-2 mol / L; the concentration of the ammonia solution is 1-2 mol / L; and the concentration of the alkaline solution is 2-4 mol / L.

[0015] In step b) of the above method, the alkaline solution is twice the molar concentration of the mixed metal salt solution A, the feed rate of the mixed metal salt solution A and the alkaline solution is 15-60 mL / min, the feed rate of the ammonia solution is 10-30 mL / min, the stirring speed is 400-600 r / min, and nitrogen gas is used for protection throughout the reaction.

[0016] In step b) of the above method, the reaction conditions are as follows: the reaction temperature is controlled at 40-80℃ (specifically 50-60℃), the pH value is controlled at 9-12, and the ammonia concentration during the reaction is controlled at 2-5g / L.

[0017] In step c) of the above method, the concentration of the zirconium salt solution is 0.5-2 mol / L, and the zirconium salt can be zirconium sulfate, zirconium nitrate or zirconium chloride; the concentration of the ammonia solution is 1-2 mol / L, and the concentration of the alkaline solution is 2-4 mol / L.

[0018] In step c) of the above method, the feed rate of the zirconium salt solution and the alkaline solution is 15-30 mL / min, the feed rate of the ammonia solution is 10-20 mL / min, the stirring speed is 300-400 r / min, and the reaction is protected by nitrogen gas throughout.

[0019] In step c) of the above method, the reaction conditions are as follows: the reaction temperature is controlled at 40-80℃ (specifically 50-60℃), the pH value is controlled at 9-11, the ammonia concentration during the reaction is controlled at 2-5g / L, and the reaction time is 2-4 hours.

[0020] In step d) of the above method, the concentration of the titanium salt solution is 0.5-2 mol / L, and the titanium salt can be titanium oxysulfate or titanium oxalate; the concentration of the ammonia solution is 1-2 mol / L, and the concentration of the alkaline solution is 2-4 mol / L.

[0021] In step d) of the above method, the feed rate of the titanium salt solution and the alkaline solution is 15-30 mL / min, the feed rate of the ammonia solution is 10-20 mL / min, the stirring speed is 300-400 r / min, and the reaction is protected by nitrogen gas throughout.

[0022] In step d) of the above method, the reaction conditions are as follows: the reaction temperature is controlled at 40-80℃ (specifically 50-60℃), the pH is controlled at 9-11, the ammonia concentration is controlled at 2-5g / L, and the reaction time is 2-4 hours.

[0023] The titanium-zirconium double-layer coated nickel-copper-iron-manganese-sodium ion battery precursor material prepared by the above method is also within the scope of protection of this invention.

[0024] The present invention also provides a layered oxide cathode material for sodium-ion batteries.

[0025] The sodium-ion battery layered oxide cathode material provided by the present invention is prepared by a method including the following steps: the above-mentioned titanium-zirconium double-layer coated nickel-copper-iron-manganese sodium-ion battery precursor material is uniformly mixed with a sodium source and calcined at 850-950°C for 10-20 hours to obtain the sodium-ion battery layered oxide cathode material.

[0026] In the above method, the sodium source can be selected from any of the following substances: sodium carbonate, sodium oxalate, sodium acetate, sodium hydroxide, etc.

[0027] The molar ratio of sodium in the sodium source to the transition metals nickel, copper, iron, and manganese in the precursor material is 1-1.05, i.e., the amount of sodium is 1-1.05.

[0028] This invention also protects the application of the above-mentioned layered oxide cathode material for sodium-ion batteries.

[0029] The application refers to the use of the layered oxide cathode material for sodium-ion batteries in the preparation of sodium-ion batteries.

[0030] This invention also protects a sodium-ion battery.

[0031] The sodium-ion battery includes a positive electrode, which comprises the above-mentioned sodium-ion battery layered oxide positive electrode material.

[0032] This invention uniformly coats two layers of metal elements on the surface of a nickel-copper-iron-manganese-based precursor. The middle layer, zirconium, migrates and does internally during sintering, stabilizing the crystal lattice. The outermost layer, titanium, effectively prevents side reactions between the internal positive electrode material and the electrolyte during charging and discharging.

[0033] Compared with the prior art, the present invention has the following beneficial technical effects:

[0034] 1. The present invention employs a double-layer coating method to greatly improve the side reactions between the material surface and the electrolyte, effectively mitigating the gas expansion problem caused by the side reactions.

[0035] 2. The zirconium in the middle layer migrates towards the center after sintering, effectively stabilizing the crystal structure and forming a gradient material. The outer titanium coating hinders electrolyte corrosion and greatly improves the material's cycle performance.

[0036] 3. This invention is easy to scale up and mass-produce in the industrial sector. When preparing cathode materials, there is no need to add dopants and double sintering coating. Optimal performance can be achieved in a single sintering, reducing process costs. Attached Figure Description

[0037] Figure 1 The image shows a SEM image of the titanium-zirconium bilayer coated nickel-copper-iron-manganese-sodium ion battery precursor material prepared in Example 1.

[0038] Figure 2 Comparison of the gas generation curves of pouch cells prepared from the cathode material prepared in Example 1 and the sodium ion layered cathode material sintered from uncoated nickel-copper-iron-manganese precursor. Detailed Implementation

[0039] The present invention will now be described in further detail with reference to specific embodiments. The given embodiments are merely illustrative of the invention and not intended to limit its scope. The embodiments provided below can serve as a guide for further improvements by those skilled in the art and do not constitute a limitation on the invention in any way.

[0040] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Unless otherwise specified, the materials and reagents used in the following examples are commercially available.

[0041] Example 1

[0042] This embodiment prepares a titanium-zirconium bilayer coated nickel-copper-iron-manganese-sodium ion precursor material, including the following steps:

[0043] 1. Prepare a 2 mol / L mixed metal salt solution A by mixing nickel sulfate, copper sulfate, ferrous sulfate, and manganese sulfate in a molar ratio of 2 / 9:1 / 9:1 / 3:1 / 3 and purge with nitrogen gas; at the same time, prepare a 1 mol / L ammonia solution and a 4 mol / L sodium hydroxide solution.

[0044] 2. The above-prepared solution A, ammonia solution, and sodium hydroxide solution were added to the reactor at a certain rate (the feed rate of the mixed metal salt solution A and the alkaline solution was 10 mL / min, and the feed rate of the ammonia solution was 10 mL / min) and stirred (stirring speed was 500 r / min). The reaction temperature was controlled at 50℃, the pH was controlled at 11, and the ammonia concentration was controlled at 3 g / L during the reaction. Nitrogen gas was used for protection throughout the reaction. The reaction was stopped when the particle size reached 10 μm to obtain Ni. 2 / 9 Cu 1 / 9 Fe 1 / 3 Mn 1 / 3 (OH)2 precursor;

[0045] 3. Prepare a 1 mol / L zirconium sulfate solution, a 1 mol / L ammonia solution, and a 2 mol / L sodium hydroxide solution. Continue to add the zirconium sulfate solution, ammonia solution, and sodium hydroxide solution to the reactor at a certain rate (the feed rate of the zirconium sulfate solution and the alkaline solution is 10 mL / min, and the feed rate of the ammonia solution is 10 mL / min) for co-precipitation and further reaction (stirring speed is 400 r / min). The reaction temperature is controlled at 50℃, the pH is controlled at 10, and the ammonia concentration is controlled at 2 g / L. The reaction is stopped after 2 hours. Nitrogen gas is used for protection throughout the reaction to obtain a zirconium-coated precursor.

[0046] 4. Prepare a 1 mol / L titanium oxysulfate solution, a 1 mol / L ammonia solution, and a 2 mol / L sodium hydroxide solution. Continue adding the titanium oxysulfate solution, ammonia solution, and sodium hydroxide solution to the reactor at a controlled rate (10 mL / min for both the titanium oxysulfate solution and the alkaline solution, and 10 mL / min for the ammonia solution) for co-precipitation and further reaction (stirring speed 400 r / min). Maintain the reaction temperature at 50℃, the pH at 10, and the ammonia concentration at 2 g / L. Stop the reaction after 2 hours. Proceed with nitrogen protection throughout the reaction to obtain zirconium-titanium double-coated Ni. 0.22 Cu 0.11 Fe 0.33 Mn 0.33 Zr 0.005 Ti 0.005 (OH)2. Figure 1 This is a SEM image of the material. Figure 1 It can be seen that the precursor has a secondary spherical morphology of about 10 μm, in which the primary particles are small and the overall sphericity is good.

[0047] Preparation of layered oxide cathode materials for sodium-ion batteries:

[0048] The prepared precursor (zirconium-titanium bilayer coated Ni) 0.22 Cu 0.11 Fe 0.33 Mn 0.33 Zr 0.005 Ti 0.005 (OH)2) and sodium carbonate (where the total molar ratio of sodium to the transition metals nickel, copper, iron and manganese in the precursor is 1.0) were uniformly mixed and then calcined at 900℃ for 15 h to obtain a double-layer zirconium-titanium coated sodium ion layered cathode material NaNi. 0.22 Cu 0.11 Fe 0.33 Mn 0.33 Zr 0.005 Ti 0.005 O 2。

[0049] The prepared sodium-ion layered cathode material was assembled into a button cell. The specific preparation method is as follows:

[0050] The prepared sodium ion layered oxide material powder was mixed with conductive carbon black SP powder and 5% by mass of polyvinylidene fluoride PVDF solution (solvent being N-methylpyrrolidone) at a mass ratio of 9:0.5:0.5 to form a slurry. This slurry was then uniformly coated onto carbon-coated aluminum foil, rolled using a roller press, and then dried in a vacuum oven for 8 hours. After drying, the slurry was placed in an argon-atmosphere glove box and assembled with a glass fiber separator, sodium sheet, and electrolyte (specifically, 1.0M NaClO4 dissolved in a mixed solvent of EC and DEC (EC:DEC = 1:1 Vol%), with 5% FEC added) to form a CR2032 coin cell.

[0051] After 50 cycles at a current density of 1C, the capacity retention is 98.2%, which is higher than that of the uncoated sodium-ion layered cathode NaNi sintered with nickel-copper-iron-manganese precursors. 2 / 9 Cu 1 / 9 Fe 1 / 3 Mn 1 / 3 O2 (Ni obtained in step 2 above) 2 / 9 Cu 1 / 9 Fe 1 / 3 Mn 1 / 3 The sodium battery prepared by directly mixing (OH)2 precursor with sodium carbonate and calcining has a capacity retention rate of 91.0%, and the sodium battery prepared in this example shows a significant advantage in cycle performance.

[0052] The prepared sodium-ion layered positive electrode material was fabricated into a positive electrode sheet, and Kuraray hard carbon negative electrode material was used to fabricate a negative electrode sheet. Small pouches were fabricated through stacking and subjected to 45°C cycling tests. During the process, the pouches were periodically removed from the oven to test volume changes and detect gas expansion. Figure 2 As can be seen, the cathode sample prepared without the coating precursor expands rapidly, and gas expansion and leakage occur after 200 cycles. In contrast, the cathode prepared with the coating precursor still produces less than 9 mL / Ah of gas after 500 cycles, showing a significant improvement in gas expansion.

[0053] Example 2

[0054] This embodiment prepares a titanium-zirconium bilayer coated nickel-copper-iron-manganese-sodium ion precursor material, including the following steps:

[0055] 1. Prepare a 1 mol / L mixed metal salt solution A by mixing nickel sulfate, copper sulfate, ferrous sulfate, and manganese sulfate in a molar ratio of 1 / 3:1 / 9:2 / 9:1 / 3 and purge with nitrogen gas; at the same time, prepare a 1 mol / L ammonia solution and a 2 mol / L sodium carbonate solution.

[0056] 2. The mixed metal salt solution A, ammonia solution, and sodium carbonate solution prepared above were added to the reactor at a certain rate (the feed rate of mixed metal salt solution A and alkaline solution was 30 mL / min, and the feed rate of ammonia solution was 20 mL / min) and stirred (stirring speed was 600 r / min). The reaction temperature was controlled at 60℃, the pH was controlled at 9, and the ammonia concentration was controlled at 2 g / L during the reaction. Nitrogen gas was used for protection throughout the reaction. The reaction was stopped when the particle size reached 10 μm to obtain Ni. 1 / 3 Cu 1 / 9 Fe 2 / 9 Mn 1 / 3 (OH)2 precursor;

[0057] 3. Prepare a 0.5 mol / L zirconium sulfate solution, a 1 mol / L ammonia solution, and a 1 mol / L sodium carbonate solution. Continue to add the zirconium sulfate solution, ammonia solution, and sodium carbonate solution to the reactor at a certain rate (the feed rate of the zirconium sulfate solution and alkaline solution is 15 mL / min, and the feed rate of the ammonia solution is 15 mL / min) for co-precipitation and further reaction (stirring speed is 300 r / min). The reaction temperature is controlled at 60℃, the pH is controlled at 9, and the ammonia concentration is controlled at 2 g / L. The reaction is stopped after 2 hours. Nitrogen gas is used for protection throughout the reaction to obtain a zirconium-coated precursor.

[0058] 4. Prepare a 1 mol / L titanium oxysulfate solution, a 1 mol / L ammonia solution, and a 2 mol / L sodium carbonate solution. Continue adding the titanium oxysulfate solution, ammonia solution, and sodium carbonate solution to the reactor at a controlled rate (15 mL / min for both the titanium oxysulfate solution and the alkaline solution, and 15 mL / min for the ammonia solution) for co-precipitation and further reaction (stirring speed 300 r / min). Maintain the reaction temperature at 60℃, the pH at 9, and the ammonia concentration at 2 g / L. Stop the reaction after 2 hours. Provide nitrogen protection throughout the reaction process to obtain zirconium-titanium double-coated Ni. 0.33 Cu 0.11 Fe 0.22 Mn 0.33 Zr 0.002 Ti 0.008 (OH)2.

[0059] Preparation of layered oxide cathode materials for sodium-ion batteries:

[0060] The prepared precursor was uniformly mixed with sodium carbonate (where the total molar ratio of sodium to the transition metals nickel, copper, iron, and manganese in the precursor was 1.05), and then calcined at 900℃ for 15 h to obtain a double-layer zirconium-titanium coated sodium ion layered cathode material NaNi. 0.33 Cu 0.1 1Fe 0.22 Mn 0.33Zr 0.002 Ti 0.008 O 2。

[0061] The prepared sodium-ion layered cathode material was assembled into a coin cell and cycled for 50 cycles at a 1C current density, maintaining a capacity retention of 97.6%. This is significantly higher than that of the uncoated sodium-ion layered cathode NaNi sintered from nickel-copper-iron-manganese precursors. 0.33 Cu 0.11 Fe 0.22 Mn 0.33 O2 (Ni obtained in step 2 above) 1 / 3 Cu 1 / 9 Fe 2 / 9 Mn 1 / 3 (OH)2 precursor, directly mixed with sodium carbonate and calcined) has a capacity retention rate of 91.6%. The sodium battery prepared in this example shows a significant advantage in cycle performance.

[0062] Example 3

[0063] This embodiment prepares a titanium-zirconium bilayer coated nickel-copper-iron-manganese-sodium ion precursor material, including the following steps:

[0064] 1. Prepare a 2 mol / L metal salt solution A by mixing nickel sulfate, copper sulfate, ferrous sulfate, and manganese sulfate in a molar ratio of 1 / 4:1 / 12:1 / 3:1 / 3 and purge with nitrogen gas; simultaneously prepare a 1 mol / L ammonia solution and a 4 mol / L sodium hydroxide solution.

[0065] 2. The prepared solution A, ammonia solution, and sodium hydroxide solution were added to the reactor at a certain rate (the feed rate of the mixed metal salt solution A and the alkaline solution was 60 mL / min, and the feed rate of the ammonia solution was 30 mL / min) and stirred (stirring speed was 400 r / min). The reaction temperature was controlled at 55℃, the pH was controlled at 11, and the ammonia concentration was controlled at 3 g / L during the reaction. The reaction was stopped when the particle size reached 10 μm, yielding Ni. 1 / 4 Cu 1 / 12 Fe 1 / 3 Mn 1 / 3 (OH)2 precursor;

[0066] 3. Prepare a 0.5 mol / L zirconium sulfate solution, a 1 mol / L ammonia solution, and a 1 mol / L sodium hydroxide solution. Continue to add the zirconium sulfate solution, ammonia solution, and sodium hydroxide solution to the reactor at a certain rate (30 mL / min for the zirconium sulfate solution and the alkaline solution, and 20 mL / min for the ammonia solution) for co-precipitation and further reaction (stirring speed 300 r / min). Control the reaction temperature at 55℃, the pH at 10, and the ammonia concentration at 2 g / L. Stop the reaction after 2 hours. Provide nitrogen protection throughout the reaction process to obtain a zirconium-coated precursor.

[0067] 4. Prepare a 0.5 mol / L titanium oxysulfate solution, a 1 mol / L ammonia solution, and a 1 mol / L sodium hydroxide solution. Continue adding the titanium oxysulfate solution, ammonia solution, and sodium hydroxide solution to the reactor at a controlled rate (30 mL / min for the titanium oxysulfate solution and the alkaline solution, and 20 mL / min for the ammonia solution) for co-precipitation and further reaction (stirring speed 300 r / min). Maintain the reaction temperature at 55℃, the pH at 10, and the ammonia concentration at 2 g / L. Stop the reaction after 2 hours. Provide nitrogen protection throughout the reaction process to obtain zirconium-titanium double-coated Ni. 0.25 Cu 0.08 Fe 0.33 Mn 0.33 Zr 0.005 Ti 0.005 (OH)2.

[0068] Preparation of layered oxide cathode materials for sodium-ion batteries:

[0069] The prepared precursor was uniformly mixed with sodium carbonate (where the total molar ratio of sodium to the transition metals nickel, copper, iron, and manganese in the precursor was 1.0), and then calcined at 900℃ for 15 h to obtain a double-layer zirconium-titanium coated sodium ion layered cathode material NaNi. 0.25 Cu 0.08 Fe 0.3 3Mn 0.33 Zr 0.005 Ti 0.005 O 2。

[0070] The prepared sodium-ion layered cathode material was assembled into a coin cell and cycled for 50 cycles at a 1C current density, maintaining a capacity retention of 97.3%. This is significantly higher than that of the uncoated sodium-ion layered cathode NaNi sintered with nickel-copper-iron-manganese precursors. 0.25 Cu 0.08 Fe 0.33 Mn 0.33 O2 (Ni obtained in step 2 above) 0.25 Cu 0.08 Fe0.33 Mn 0.33 The sodium battery prepared in this example, which is obtained by directly mixing and calcining (OH)2 precursor with sodium carbonate), has a capacity retention rate of 90.2%. The sodium battery exhibits a significant advantage in cycle performance.

Claims

1. A method for preparing a titanium-zirconium double-layer coated nickel-copper-iron-manganese-sodium ion battery precursor material, comprising the following steps: a) Prepare a mixed metal salt solution A by mixing nickel, copper, iron, and manganese sources in a molar ratio of x:y:z:1-xyz and purging with nitrogen gas; simultaneously prepare an ammonia solution and an alkaline solution; wherein, 0.2≤x≤0.5, 0.05≤y≤0.2, 0.2≤z≤0.4, b) Add the mixed metal salt solution A, ammonia solution, and alkaline solution prepared in step a) into the reactor and stir until the particle size reaches 10 ± 0.5 μm, then stop the reaction to obtain Ni. x Cu y Fe z Mn 1-x-y-z (OH)2 precursor; c) Prepare a zirconium salt solution, an ammonia solution, and an alkaline solution. Add the zirconium salt solution, the ammonia solution, and the alkaline solution to the reaction vessel in step 2) for co-precipitation and continue stirring to obtain a zirconium-coated precursor. d) Prepare a titanium salt solution, an ammonia solution, and an alkaline solution. Add these solutions to the reaction vessel from step 3) for co-precipitation and continue stirring to obtain zirconium-titanium double-coated Ni. x Cu y Fe z Mn 1-x-y-z Zr a Ti b (OH)2, where 0.2≤x≤0.5, 0.05≤y≤0.2, 0.2≤z≤0.4, 0.01≤a≤0.1, and 0.01≤b≤0.

1.

2. The preparation method according to claim 1, characterized in that: In step a), the nickel source is selected from at least one of the following: nickel sulfate, nickel nitrate, or nickel chloride; the copper source is copper sulfate, copper nitrate, or copper chloride; the iron source is ferrous sulfate and / or ferrous chloride; and the manganese source is selected from at least one of the following: manganese sulfate, manganese nitrate, or manganese chloride. Alternatively, in step a), the alkaline solution is a sodium hydroxide solution or a sodium carbonate solution; Alternatively, in step a), the concentration of the mixed metal salt solution A is 1-2 mol / L; the concentration of the ammonia solution is 1-2 mol / L; and the concentration of the alkaline solution is 2-4 mol / L.

3. The preparation method according to claim 1, characterized in that: In step b), the alkaline solution has a molar concentration twice that of the mixed metal salt solution A, the feed rate of the mixed metal salt solution A and the alkaline solution is 15-60 mL / min, the feed rate of the ammonia solution is 10-30 mL / min, the stirring speed is 400-600 r / min, and the reaction is protected by nitrogen gas throughout. Alternatively, in step b), the reaction conditions are as follows: the reaction temperature is controlled at 40-80℃, the pH value is controlled at 9-12, and the ammonia concentration during the reaction is controlled at 2-5g / L.

4. The preparation method according to claim 1, characterized in that: In step c), the concentration of the zirconium salt solution is 0.5-2 mol / L, and the zirconium salt is zirconium sulfate, zirconium nitrate, or zirconium chloride; the concentration of the ammonia solution is 1-2 mol / L, and the concentration of the alkaline solution is 2-4 mol / L. Alternatively, in step c), the feed rate of the zirconium salt solution and the alkaline solution is 15-30 mL / min, the feed rate of the ammonia solution is 10-20 mL / min, the stirring speed is 300-400 r / min, and the reaction is protected by nitrogen gas throughout. Alternatively, in step c), the reaction conditions are as follows: the reaction temperature is controlled at 40-80℃, the pH value is controlled at 9-11, the ammonia concentration is controlled at 2-5g / L, and the reaction time is 2-4 hours.

5. The preparation method according to claim 1, characterized in that: In step d), the concentration of the titanium salt solution is 0.5-2 mol / L, and the titanium salt is titanium oxysulfate or titanium oxalate; the concentration of the ammonia solution is 1-2 mol / L, and the concentration of the alkaline solution is 2-4 mol / L. Alternatively, in step d), the feed rate of the titanium salt solution and the alkaline solution is 15-30 mL / min, the feed rate of the ammonia solution is 10-20 mL / min, the stirring speed is 300-400 r / min, and the reaction is protected by nitrogen gas throughout. Alternatively, in step d), the reaction conditions are as follows: the reaction temperature is controlled at 40-80℃, the pH is controlled at 9-11, the ammonia concentration is controlled at 2-5g / L, and the reaction time is 2-4 hours.

6. The titanium-zirconium bilayer coated nickel-copper-iron-manganese-sodium ion battery precursor material prepared by the method of any one of claims 1-5.

7. A method for preparing a layered oxide cathode material for sodium-ion batteries, comprising the following steps: uniformly mixing the titanium-zirconium double-layer coated nickel-copper-iron-manganese sodium-ion battery precursor material as described in claim 6 with a sodium source, and calcining to obtain the product.

8. The preparation method according to claim 7, characterized in that: The sodium source is selected from at least one: sodium carbonate, sodium oxalate, sodium acetate, and sodium hydroxide; Alternatively, the total molar ratio of sodium in the sodium source to the total molar ratio of nickel, copper, iron, and manganese transition metals in the precursor material is 1-1.05; Alternatively, the calcination conditions are: calcination at 850-950℃ for 10-20 hours.

9. The sodium-ion battery layered oxide cathode material prepared by the method of claim 7 or 8.

10. A sodium-ion battery, comprising a positive electrode, wherein the positive electrode is the layered oxide positive electrode material of claim 9.

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