Titanium-doped layered oxide material for sodium-ion battery, preparation method therefor, and use thereof

Abstract

A titanium-doped layered oxide material for a sodium-ion battery, a preparation method therefor, and the use thereof. The preparation method comprises the following steps: mixing a nickel-iron-manganese salt solution, a precipitant solution, a complexing agent solution and a titanium source solution to perform a coprecipitation reaction, so as to obtain a precursor material of which primary particles are radially packed; mixing a sodium source and the precursor material and sintering same, so as to obtain the titanium-doped layered oxide material for a sodium-ion battery. The preparation method uses titanium doping and morphology regulation to improve the structural strength and cycle performance of the material, thereby improving lattice oxygen stability during the process of high-voltage deep desodiation, suppressing multiple phase transition reactions and also improving the plateau voltage and the energy density.

Description

A titanium-doped sodium-electrolyte layered oxide material and its preparation method and application Technical Field

[0001] The present application belongs to the field of battery technology and relates to a titanium-doped sodium-electrolyte layered oxide material and a preparation method and application thereof. Background Art

[0002] With the rapid growth in demand for lithium-ion batteries in consumer electronics, power batteries, and energy storage, lithium resource prices remain high, and supply is becoming increasingly tight. While sodium-ion batteries have a lower energy density than lithium-ion batteries, they offer advantages in resource reserves, cost, safety, rate capability, and low-temperature performance. Therefore, sodium-ion batteries are being developed as an alternative to lithium-ion batteries.

[0003] The core characteristics of high-performance sodium-ion batteries, such as energy density, cycle life and rate performance, are mainly determined by the cathode material. Transition metal layered oxide cathode materials such as NaNi a Fe b Mn c O2 (a + b + c = 1), has excellent comprehensive performance. At present, the industrial preparation of positive electrode materials mainly focuses on high-temperature solid-phase method and co-precipitation method. Although the high-temperature solid-phase method is simple and can achieve large-scale preparation, the chemical composition of the product is not uniform enough, the particle morphology is irregular and easy to agglomerate, and the tap density is low. The above disadvantages will lead to poor consistency and yield of products in different batches, and the optimal electrochemical performance cannot be exerted. The co-precipitation method is simple to operate, has low energy consumption, can achieve the desired spherical particle preparation, and the transition metal atomic scale is uniformly distributed, the tap density is high, and a multi-dimensional balance of "performance-cost-mass production-safety" can be achieved. Therefore, the development of the positive electrode material NaNi a Fe b Mn c The co-precipitation preparation method of O2 is crucial.

[0004] Other methods used to prepare sodium cathode materials include hydrothermal, sol-gel, and electrospinning. These methods, on the one hand, produce products with uneven uniformity, low tap density, and poor dispersion; they also suffer from poor batch-to-batch consistency, low material yield, and poor reliability. Furthermore, these methods are not amenable to industrial-scale large-scale production, and their commercialization prospects are limited.

[0005] In addition, in order to suppress the inclusion of NaNi a Fe b Mn cDoping is the most reliable and effective modification method for layered oxide cathode materials, including O2, to improve lattice structure stability and increase the cutoff voltage to 4.2V, thereby significantly increasing specific capacity and energy density. Research has shown that Ti doping effectively improves lattice stability through strong Ti-O bonds, as shown in the titanium-doped modified P2-type layered sodium-ion battery cathode material and its preparation method disclosed in CN 113921781A. However, the above strategies still have the following limitations: doping modification cannot control the random orientation of primary grains, inevitably leading to uneven volume expansion / contraction during charge and discharge, resulting in phase changes and cracks.

[0006] Furthermore, adopting a single modification measure has limitations in improving performance, failing to leverage the synergistic effects of different modification measures. A single modification measure, such as element doping, can effectively increase energy density but often fails to improve cycling performance. Simply optimizing morphology can improve cycling performance but often fails to increase energy density.

[0007] Based on the above research, it is necessary to provide a method for preparing titanium-doped sodium-electrolyte layered oxide materials, which improves the cycle performance and energy density through titanium doping and morphology control.

[0008] Summary of the Invention

[0009] 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.

[0010] The purpose of this application is to provide a titanium-doped sodium layered oxide material and its preparation method and application. The preparation method improves the material structural strength and cycle performance through titanium doping and morphology control, improves the lattice oxygen stability during high-voltage deep sodium removal, inhibits multiple phase change reactions, and improves the voltage platform and energy density.

[0011] To achieve this goal, this application adopts the following technical solutions:

[0012] In a first aspect, the present application provides a method for preparing a titanium-doped sodium-electrolyte layered oxide material, the preparation method comprising the following steps:

[0013] (1) mixing a nickel-iron-manganese salt solution, a precipitant solution, a complexing agent solution, and a titanium source solution to perform a coprecipitation reaction to obtain a precursor material with radially stacked primary particles;

[0014] (2) Mixing and sintering the sodium source and the precursor material of step (1) to obtain the titanium-doped sodium layered oxide material.

[0015] Since the stacking mode of the primary particles of the positive electrode material closely affects the electrochemical performance, the present application prepares a material with radially stacked primary particles. Compared with mixed stacking and flat stacking, the radial stacking of the primary particles has a consistent crystal orientation, which can significantly reduce the inter-granular stress induced by volume change through coordinated expansion and contraction, thereby significantly inhibiting the pulverization of secondary particles and improving structural strength and cycle performance; in addition, the present application constructs a strong Ti-O bond by doping with the metal element Ti, so that the oxygen atoms have more negative charge, effectively reducing the excessive oxidation of oxygen, thereby improving the lattice oxygen stability during high-voltage deep sodium removal, inhibiting multiple phase change reactions, and improving the voltage platform and energy density. Therefore, the present application improves the energy density, structural stability and cycle performance of the positive electrode material of sodium ion batteries by synergistically modifying and regulating the chemical composition (Ti doping) and micromorphology (radial stacking of primary particles) of the precursor and the positive electrode material.

[0016] In one embodiment, the concentration of the titanium source solution in step (1) is 0.1-0.5 mol / L, for example, it can be 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, 0.4 mol / L or 0.5 mol / L, and the flow rate is 0.2-3 L / h, for example, it can be 0.5 L / h, 1 L / h, 1.5 L / h, 2 L / h, 2.5 L / h or 3 L / h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0017] In one embodiment, the titanium source solution in step (1) further comprises an additive, wherein the additive comprises any one of citric acid, ascorbic acid or sodium persulfate, or a combination of at least two thereof.

[0018] The present application adopts a low-concentration titanium source solution and adds a reducing agent for doping to prevent element segregation, thereby achieving homogeneous co-precipitation.

[0019] In one embodiment, the molar ratio of the additive to the titanium source in the titanium source solution of step (1) is 1:(1-10), for example, it can be 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9 or 1:10, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0020] In one embodiment, the titanium source in the titanium source solution in step (1) includes any one of titanyl sulfate, titanium dioxide, titanium tetrachloride or titanium nitrate, or a combination of at least two thereof.

[0021] In one embodiment, the pH of the coprecipitation reaction in step (1) is 9-12, for example, 9, 10, 11 or 12, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0022] In one embodiment, the concentration of the complexing agent in the coprecipitation reaction system of step (1) is 0.01-0.5 mol / L, for example, it can be 0.01 mol / L, 0.05 mol / L, 0.1 mol / L, 0.3 mol / L or 0.5 mol / L, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable, preferably 0.05-0.2 mol / L.

[0023] This application controls the OH - The concentration (i.e., pH) and the concentration of the complexing agent are convenient for promoting the growth of specific crystal planes of the precursor, thereby obtaining a radially stacked microstructure.

[0024] In one embodiment, the temperature of the coprecipitation reaction in step (1) is 20-70°C, for example, 20°C, 40°C, 60°C or 70°C, and the stirring rate is 200-400 rpm, for example, 250 rpm, 300 rpm or 350 rpm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0025] The present application reasonably controls the titanium doping concentration by controlling the concentration of the titanium source solution, the flow rate of the titanium source solution, the flow rate of the complexing agent solution, the flow rate of the ternary salt solution, etc. through the coordination of multiple parameters, thereby preventing the problem of component segregation and the generation of impurity phases caused by the precipitation of titanium alone.

[0026] In one embodiment, the concentration of the complexing agent solution in step (1) is 0.1-1.0 mol / L, for example, 0.1 mol / L, 0.2 mol / L, 0.5 mol / L, 0.8 mol / L or 1.0 mol / L, and the flow rate is 0.8-2 L / h, for example, 1 L / h, 1.5 L / h or 2 L / h, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0027] In one embodiment, the complexing agent solution in step (1) includes any one of EDTA, ammonia water or sodium citrate, or a combination of at least two of them.

[0028] In one embodiment, the concentration of the precipitant solution in step (1) is 6-10 mol / L, for example, 6 mol / L, 8 mol / L or 10 mol / L, and the flow rate is 2-4 L / h, for example, 2 L / h, 3 L / h or 4 L / h, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0029] In one embodiment, the total metal ion concentration of the nickel-iron-manganese salt solution in step (1) is 0.5-2 mol / L, for example, 1 mol / L, 1.5 mol / L or 2 mol / L, and the flow rate is 5-10 L / h, for example, 5 L / h, 8 L / h or 10 L / h, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0030] In one embodiment, after the coprecipitation reaction in step (1) is completed, centrifugal washing is performed using alkaline solution and pure water, and then drying is performed.

[0031] In one embodiment, the drying temperature is 100-200° C., for example, 100° C., 150° C. or 200° C., but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0032] The drying methods described in this application include conventional drying in the atmosphere, drying under vacuum, or drying under the protection of nitrogen or an inert atmosphere.

[0033] In one embodiment, the sintering temperature in step (2) is 800-1000°C, for example, 800°C, 900°C or 1000°C, and the sintering time is 10-20h, for example, 12h, 15h or 20h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0034] In one embodiment, the sodium source in step (2) comprises sodium hydroxide and / or sodium carbonate.

[0035] As an optional technical solution of the preparation method described in this application, the preparation method comprises the following steps:

[0036] (1) mixing a nickel-iron-manganese salt solution, a precipitant solution, a complexing agent solution, and a titanium source solution to perform a coprecipitation reaction, wherein the pH of the coprecipitation reaction is 9-12, the temperature is 20-70° C., the stirring rate is 200-400 rpm, and the concentration of the complexing agent in the coprecipitation reaction system is 0.01-0.5 mol / L. After the coprecipitation reaction is completed, centrifugation washing is performed with alkali solution and pure water, and then drying is performed to obtain a precursor material with radially stacked primary particles;

[0037] The concentration of the titanium source solution is 0.1-0.5 mol / L, the flow rate is 0.2-3 L / h, the concentration of the complexing agent solution is 0.1-1.0 mol / L, the flow rate is 0.8-2 L / h, the concentration of the precipitant solution is 6-10 mol / L, the flow rate is 2-4 L / h, and the total metal ion concentration of the nickel-iron-manganese salt solution is 0.5-2 mol / L, the flow rate is 5-10 L / h;

[0038] (2) Mix the sodium source and the precursor material described in step (1), and then sinter at a temperature of 800 - 1000 °C for 10 - 20 h to obtain the titanium-doped sodium-ion battery layered oxide material.

[0039] In a second aspect, the present application provides a titanium-doped sodium-ion battery layered oxide material, which is prepared by the preparation method as described in the first aspect.

[0040] In one embodiment, the chemical general formula of the titanium-doped sodium-ion battery layered oxide material is NaNi x Fe y Mn z Ti d O 2， where 0 < x < 1, for example, it can be 0.1, 0.3, 0.5, 0.7 or 0.8; 0 < y < 1, for example, it can be 0.1, 0.3, 0.5, 0.7 or 0.8; 0 < z < 1, for example, it can be 0.1, 0.3, 0.5, 0.7 or 0.8; 0 < d ≤ 0.2, for example, it can be 0.02, 0.05, 0.1, 0.15 or 0.2, and x + y + z + d = 1.

[0041] In a third aspect, the present application provides a sodium-ion battery, which includes the titanium-doped sodium-ion battery layered oxide material as described in the second aspect.

[0042] Compared with the prior art, the present application has the following beneficial effects:

[0043] (1) The present application uses an industrially mature co-precipitation process to realize the preparation of a Ti-doped radially stacked sodium-ion battery cathode material. Compared with the electrospinning method, hydrothermal method and sol-gel method, this preparation method is simple to operate, has low energy consumption, and has a mature industrial foundation. In addition, the prepared cathode material can achieve an atomic-level uniform distribution, has good dispersibility of spherical particles, a high tap density, and good product consistency and repeatability.

[0044] (2) The present application simultaneously improves the energy density, structural stability and cycling performance of the sodium-ion battery cathode material by means of synergistic modification and regulation of the chemical composition (Ti doping) and microscopic morphology (radial stacking of primary particles) of the cathode material.

[0045] Other aspects can be understood after reading and understanding the drawings and the detailed description. Description of the Drawings

[0046] The drawings are used to provide a further understanding of the technical solutions herein, and constitute a part of the specification. Together with the embodiments of the present application, they are used to explain the technical solutions herein, and do not constitute a limitation to the technical solutions herein.

[0047] Figure 1 is a SEM image of the precursor material described in step (1) of Example 1 of the present application at a magnification of 30,000 times. DETAILED DESCRIPTION

[0048] 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.

[0049] Example 1

[0050] This embodiment provides a method for preparing a titanium-doped sodium-electrolyte layered oxide material, the preparation method comprising the following steps:

[0051] (1) A nickel-iron-manganese salt solution at a flow rate of 8 L / h, a precipitant solution at a flow rate of 6 L / h, a complexing agent solution at a flow rate of 1.2 L / h, and a titanium source solution at a flow rate of 1 L / h were injected into a 200 L continuously stirred reactor to carry out a coprecipitation reaction. The pH of the coprecipitation reaction was 10.2, the temperature was 60 ° C, the stirring rate was 350 rpm, and the concentration of the complexing agent in the coprecipitation reaction system was 0.1 mol / L. After the coprecipitation reaction was carried out for 80 h to make the particle size reach 6 μm, the particles were centrifuged and washed with alkali solution and pure water, and then dried in an atmosphere at 120 ° C for 24 h to obtain a precursor material with radial stacking of primary particles. The SEM image of the precursor material at a magnification of 30,000 times is shown in Figure 1;

[0052] The titanium source solution includes a 0.2 mol / L titanium sulfate and a 0.04 mol / L ascorbic acid solution; the complexing agent solution is a 0.2 mol / L sodium citrate solution; the precipitant solution is a 10 mol / L sodium hydroxide solution; the total metal ion concentration of the nickel-iron-manganese salt solution is 2 mol / L, and the nickel-iron-manganese salt solution includes a sulfate solution of Ni, Fe, and Mn elements;

[0053] (2) Sodium carbonate and the precursor material of step (1) are mixed, and then sintered at a temperature of 900° C. for 12 hours to obtain the titanium-doped sodium layered oxide material with radially stacked primary particles.

[0054] Example 2

[0055] This embodiment provides a method for preparing a titanium-doped sodium-electrolyte layered oxide material, the preparation method comprising the following steps:

[0056] (1) injecting a nickel iron manganese salt solution at a flow rate of 5 L / h, a precipitant solution at a flow rate of 2 L / h, a complexing agent solution at a flow rate of 0.8 L / h, and a titanium source solution at a flow rate of 0.2 L / h into a 200 L continuously stirred reactor to carry out a coprecipitation reaction, wherein the pH of the coprecipitation reaction is 9.8, the temperature is 70 ° C, the stirring rate is 400 rpm, and the concentration of the complexing agent in the coprecipitation reaction system is 0.01 mol / L. After the coprecipitation reaction reaches a particle size of 5 μm, the particles are centrifuged and washed with alkali solution and pure water, and then dried at 100 ° C in an atmospheric atmosphere for 24 hours to obtain a precursor material with radial stacking of primary particles;

[0057] The titanium source solution is a solution of titanium oxysulfate with a concentration of 0.5 mol / L and ascorbic acid with a concentration of 0.05 mol / L; the complexing agent solution includes a sodium citrate solution with a concentration of 0.5 mol / L; the precipitant solution is a sodium hydroxide solution with a concentration of 6 mol / L; the total metal ion concentration of the nickel-iron-manganese salt solution is 2 mol / L, and the nickel-iron-manganese salt solution includes a sulfate solution of Ni, Fe and Mn elements;

[0058] (2) Sodium carbonate and the precursor material of step (1) are mixed, and then sintered at a temperature of 800° C. for 20 hours to obtain the radially stacked titanium-doped sodium layered oxide material.

[0059] Example 3

[0060] This embodiment provides a method for preparing a titanium-doped sodium-electrolyte layered oxide material, the preparation method comprising the following steps:

[0061] (1) injecting a nickel iron manganese salt solution at a flow rate of 10 L / h, a precipitant solution at a flow rate of 4 L / h, a complexing agent solution at a flow rate of 2 L / h, and a titanium source solution at a flow rate of 3 L / h into a 200 L continuously stirred reactor to carry out a coprecipitation reaction, wherein the pH of the coprecipitation reaction is 12, the temperature is 40 ° C, the stirring rate is 200 rpm, and the concentration of the complexing agent in the coprecipitation reaction system is 0.5 mol / L. After the coprecipitation reaction reaches a particle size of 6 μm, the particles are centrifuged and washed with alkali solution and pure water, and then dried at 120 ° C in an atmospheric atmosphere for 24 h to obtain a precursor material with radial stacking of primary particles;

[0062] The titanium source solution includes a 0.1 mol / L titanium sulfate and a 0.1 mol / L ascorbic acid solution; the complexing agent solution is a 0.1 mol / L sodium citrate solution; the precipitant solution is a 10 mol / L sodium hydroxide solution; the total metal ion concentration of the nickel-iron-manganese salt solution is 0.5 mol / L, and the nickel-iron-manganese salt solution includes a sulfate solution of Ni, Fe and Mn elements;

[0063] (2) Sodium carbonate and the precursor material of step (1) are mixed, and then sintered at a temperature of 1000° C. for 10 hours to obtain the radially stacked titanium-doped sodium layered oxide material.

[0064] Example 4

[0065] This embodiment provides a method for preparing a titanium-doped sodium-electrolyte layered oxide material. The preparation method is the same as that of Example 1, except that the titanium source solution in step (1) does not contain ascorbic acid.

[0066] Example 5

[0067] This embodiment provides a method for preparing a titanium-doped sodium layered oxide material. The preparation method is the same as that of Example 1, except that the concentration of the titanium source solution in step (1) is 0.01 mol / L.

[0068] Example 6

[0069] This embodiment provides a method for preparing a titanium-doped sodium-electrolyte layered oxide material. The preparation method is the same as that of Example 1, except that the concentration of the titanium source solution in step (1) is 1.0 mol / L.

[0070] Example 7

[0071] This embodiment provides a method for preparing a titanium-doped sodium layered oxide material. The preparation method is the same as that of Example 1, except that the feed rate of the complexing agent solution in step (1) is changed so that the complexing agent concentration of the coprecipitation reaction system is 0.001 mol / L.

[0072] Example 8

[0073] This embodiment provides a method for preparing a titanium-doped sodium layered oxide material. The preparation method is the same as that of Example 1, except that the feed rate of the complexing agent solution in step (1) is changed so that the complexing agent concentration in the coprecipitation reaction system in step (1) is 1 mol / L.

[0074] Comparative Example 1

[0075] This comparative example provides a method for preparing a sodium layered oxide material. The preparation method is the same as Example 1 except that no titanium source solution is added during co-precipitation in step (1).

[0076] Comparative Example 2

[0077] This comparative example provides a method for preparing a titanium-doped sodium layered oxide material. The preparation method is the same as Example 1, except that the complexing agent in step (1) is a mixture of sodium citrate and ammonia water, the pH of the coprecipitation reaction is 8, the complexing agent concentration of the coprecipitation reaction system is 3 mol / L, and the primary particles of the precursor material in step (1) are distributed laterally.

[0078] The titanium-doped sodium layered oxide material obtained in the above examples and comparative examples was used as the main positive electrode material to prepare the positive electrode, and the metal sodium sheet was used as the negative electrode to assemble into a CR2032 button battery. The electrochemical performance test was then carried out under the conditions of charge and discharge voltage of 2.0 to 4.0 V. The test results are shown in Table 1.

[0079] Table 1

[0080] From Table 1 we can see that:

[0081] It can be seen from Example 1 and Comparative Examples 1-2 that the present application can obtain a sodium ion battery with excellent comprehensive performance by doping titanium and regulating the specific micromorphology; it can be seen from Example 1 and Example 4 that the present application adds additives to the titanium source solution, which can improve the uniformity of element distribution and prevent component segregation, thereby improving battery performance; it can be seen from Example 1 and Examples 5-6 that the concentration of the titanium source solution of the present application will affect the uniform precipitation of the elements, thereby affecting the battery performance; it can be seen from Example 1 and Examples 7-8 that the concentration of the complexing agent solution in the co-precipitation reaction system of the present application will affect the stacking mode of the primary particles of the material, thereby affecting the battery performance.

[0082] In summary, the present application provides a titanium-doped sodium layered oxide material, a preparation method and an application thereof. The preparation method improves the structural strength and cycle performance of the material through titanium doping and morphology control, improves the lattice oxygen stability during high-voltage deep sodium removal, inhibits multiple phase change reactions, and improves the voltage platform and energy density.

[0083] 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 titanium-doped sodium-ion battery layered oxide material, comprising the following steps: (1) Mix a nickel-iron-manganese salt solution, a precipitant solution, a complexing agent solution, and a titanium source solution, and perform a coprecipitation reaction to obtain a precursor material with a radial stacking of primary particles; (2) Mix a sodium source and the precursor material obtained in step (1) and sinter them to obtain the titanium-doped sodium-ion battery layered oxide material.

2. According to the preparation method described in claim 1, wherein, the concentration of the titanium source solution in step (1) is 0.1 - 0.5 mol / L, and the flow rate is 0.2 - 3 L / h; Optionally, the titanium source solution in step (1) further includes an additive, and the additive includes any one or a combination of at least two of citric acid, ascorbic acid, or sodium persulfate; Optionally, the molar ratio of the additive to the titanium source in the titanium source solution in step (1) is 1:(1 - 10); Optionally, the titanium source in the titanium source solution in step (1) includes any one or a combination of at least two of titanium oxysulfate, titanium dioxide, titanium tetrachloride, or titanium nitrate.

3. According to the preparation method described in claim 1 or 2, wherein, the pH of the coprecipitation reaction in step (1) is 9 - 12; Optionally, the concentration of the complexing agent in the coprecipitation reaction system in step (1) is 0.01 - 0.5 mol / L, and further optionally 0.05 - 0.2 mol / L; Optionally, the temperature of the coprecipitation reaction in step (1) is 20 - 70 °C, and the stirring rate is 200 - 400 rpm.

4. According to the preparation method described in any one of claims 1 - 3, wherein, the concentration of the complexing agent solution in step (1) is 0.1 - 1.0 mol / L, and the flow rate is 0.8 - 2 L / h; Optionally, the complexing agent solution in step (1) includes any one or a combination of at least two of EDTA, ammonia water, or sodium citrate.

5. According to the preparation method described in any one of claims 1 - 4, wherein, the concentration of the precipitant solution in step (1) is 6 - 10 mol / L, and the flow rate is 2 - 4 L / h; Optionally, the total metal ion concentration of the nickel-iron-manganese salt solution in step (1) is 0.5 - 2 mol / L, and the flow rate is 5 - 10 L / h.

6. According to the preparation method described in any one of claims 1 - 5, wherein, after the coprecipitation reaction in step (1), centrifuge and wash with an alkali solution and pure water, and then dry; Optionally, the drying temperature is 100 - 200 °C.

7. According to the preparation method described in any one of claims 1 - 6, wherein, the sintering temperature in step (2) is 800 - 1000 °C, and the time is 10 - 20 h; Optionally, the sodium source in step (2) includes sodium hydroxide and / or sodium carbonate.

8. According to the preparation method described in any one of claims 1 - 7, wherein, the preparation method includes the following steps: (1) Mix a nickel-iron-manganese salt solution, a precipitant solution, a complexing agent solution, and a titanium source solution to conduct a coprecipitation reaction. The pH of the coprecipitation reaction is 9 - 12, the temperature is 20 - 70 °C, the stirring rate is 200 - 400 rpm, the concentration of the complexing agent in the coprecipitation reaction system is 0.01 - 0.5 mol / L. After the coprecipitation reaction, centrifuge and wash with an alkali solution and pure water, and then dry to obtain a precursor material with primary particles radially stacked. The concentration of the titanium source solution is 0.1 - 0.5 mol / L, the flow rate is 0.2 - 3 L / h, the concentration of the complexing agent solution is 0.1 - 1.0 mol / L, the flow rate is 0.8 - 2 L / h, the concentration of the precipitant solution is 6 - 10 mol / L, the flow rate is 2 - 4 L / h, and the total metal ion concentration of the nickel-iron-manganese salt solution is 0.5 - 2 mol / L, the flow rate is 5 - 10 L / h; (2) Mix a sodium source and the precursor material obtained in step (1), and then sinter at a temperature of 800 - 1000 °C for 10 - 20 h to obtain the titanium-doped sodium-ion layered oxide material.

9. A titanium-doped sodium-ion layered oxide material prepared by the preparation method according to any one of claims 1 - 8.

10. A sodium-ion battery comprising the titanium-doped sodium-ion layered oxide material according to claim 9.

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