A nickel-iron-manganese ternary precursor, preparation method and sodium ion battery positive electrode material

Abstract

The invention discloses a nickel-iron-manganese ternary precursor, a preparation method and a positive electrode material for a sodium ion battery, and relates to the technical field of new energy materials. A mixed metal salt solution composed of a nickel salt, a ferrous salt and a manganese salt, a precipitant and a complexing agent are introduced into a reactor in which a base liquid has been adjusted to carry out a coprecipitation reaction, and the concentration of the mixed metal salt solution is controlled to be ≤2.0 mol / L, the concentration of the precipitant is ≤11.0 mol / L, and the concentration of the complexing agent is ≤1.0 mol / L; the reaction is continued until the particle size of the product reaches the target particle size. The method provided by the present invention does not need to add an additional reducing agent or dilute the feed liquid during the preparation process, and can control the nickel-iron-manganese ternary precursor to basically not produce small balls during the growth process, can smoothly grow to the required target particle size, and can realize the regulation of the primary particle morphology, the sphericity is good, which is conducive to industrial mass production, and the positive electrode material for a sodium ion battery prepared by the method has excellent electrochemical performance.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy materials, and in particular to a nickel-iron-manganese ternary precursor, a preparation method and a positive electrode material for a sodium ion battery. Background Art

[0002] The key material of sodium-ion batteries is the cathode material, and its cost is one of the main factors determining the cost of sodium-ion batteries. Layered transition metal oxide cathode materials have the advantages of low cost, wide source of raw materials, simple synthesis process, easy large-scale industrial production, high energy density, high voltage platform, and excellent comprehensive performance, and have become the mainstream research direction of sodium-ion battery cathode materials.

[0003] Just like the nickel-cobalt-manganese ternary precursors used in lithium-ion batteries, the nickel-iron-manganese ternary precursors used in sodium-ion batteries are currently mainly produced industrially using the liquid phase coprecipitation method. In the commonly used liquid phase coprecipitation system with ammonia water as the complexing agent, due to the particularity of iron ions, when preparing the nickel-iron-manganese ternary precursor, there are problems such as small balls being easily produced during the growth process and the particles being difficult to grow further. The larger the precursor particles, the more serious these problems are, and the higher the iron content, the more obvious these problems are.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] The purpose of the present invention is to provide a nickel-iron-manganese ternary precursor, a preparation method and a sodium ion battery positive electrode material to solve the problems that small balls are easily produced and the particles are difficult to grow further during the preparation process of the nickel-iron-manganese ternary precursor, which is conducive to industrial mass production, and the sodium ion battery positive electrode material prepared by the precursor has excellent electrochemical performance.

[0006] The inventors found that, because ferrous ions cannot be complexed with ammonium ions on the one hand, and are very easy to oxidize on the other hand, there are problems such as small balls are easily produced during the growth process and particles are difficult to grow further when preparing nickel-iron-manganese ternary precursors. To solve these problems, the present invention uses oxalic acid as a new complexing agent, which can not only complex nickel-iron-manganese ions at the same time, but also has reducibility, and can inhibit the oxidation of ferrous ions to a certain extent, and provides a new liquid phase coprecipitation scheme for nickel-iron-manganese ternary precursors, which can control the nickel-iron-manganese ternary precursors to basically not produce small balls during the growth process without diluting the feed liquid and adding additional reducing agents, and can smoothly grow to the required target particle size, with good sphericity and adjustable particle morphology, and is suitable for industrial mass production.

[0007] Specifically, the present invention is achieved by:

[0008] In a first aspect, the present invention provides a method for preparing a nickel-iron-manganese ternary precursor, which comprises the following steps:

[0009] A mixed metal salt solution consisting of nickel salt, ferrous salt and manganese salt, a precipitant and a complexing agent are introduced into a reactor prepared with a base liquid for co-precipitation reaction, the concentration of the mixed metal salt solution is controlled to be ≤2.0 mol / L, the concentration of the precipitant is ≤11.0 mol / L, and the concentration of the complexing agent is ≤1.0 mol / L. Inert gas is continuously introduced during the reaction, and the reaction is continued until the particle size of the product reaches the target particle size; the complexing agent is an oxalic acid solution.

[0010] During the granulation stage, the pH in the reactor is controlled to be a first pH value, and the concentration of oxalate ions is a first oxalate value. During the growth stage, the pH in the reactor is controlled to be a second pH value, and the concentration of oxalate ions is a second oxalate value. In addition, 12.0 ≥ the first pH value > the second pH value ≥ 10.0, and 0.01 mol / L ≤ the first oxalate value < the second oxalate value ≤ 1.0 mol / L.

[0011] The method provided by the present invention does not require the addition of additional reducing agents or dilution of feed liquid during the preparation process of the nickel-iron-manganese ternary precursor, and can control the nickel-iron-manganese ternary precursor to basically not produce small balls during the growth process, can smoothly grow to the required target particle size, and can achieve the regulation of the primary particle morphology, with good sphericity, which is conducive to industrial mass production.

[0012] The inventors found that the morphology of the primary particles of the product can be effectively controlled by adjusting the pH and oxalate concentration of the reaction system. The morphology of the primary particles can be strip-shaped, thin strip-shaped, thick strip-shaped or flake-shaped.

[0013] Choosing oxalic acid has the following advantages: oxalic acid has certain reducing properties and can simultaneously complex nickel, iron and manganese ions. Therefore, there is no need to add additional reducing agents during the preparation of the ternary precursor. The nickel, iron and manganese ternary precursor can be controlled to basically not produce small balls during the growth process and can grow smoothly to the required target particle size, which is suitable for industrial mass production.

[0014] In addition, the method provided by the present invention has universal applicability and is suitable for the preparation of other nickel-iron-manganese ternary precursors of different sizes and different proportions.

[0015] In a preferred embodiment of the present invention, the reaction is continued until the particle size D50 of the product reaches the target particle size of 1.0-20.0 μm, thereby nickel-iron-manganese ternary precursors of different morphologies and sizes can be prepared.

[0016] For example, in the granulation stage, the pH of the solution in the reactor is controlled to be 11.50-11.60, and the oxalate concentration is 0.30 mol / L; in the growth stage, the pH of the solution in the reactor is controlled to be 11.20-11.30, and the oxalate concentration is 0.35 mol / L. Thus, primary particles in the form of thin strips can be obtained.

[0017] For example, in the granulation stage, the pH of the solution in the reactor is controlled to be 11.10-11.20, and the oxalate concentration is 0.30 mol / L; in the growth stage, the pH of the solution in the reactor is controlled to be 10.80-10.90, and the oxalate concentration is 0.35 mol / L. Thus, primary particles in the form of flakes can be obtained.

[0018] In an optional embodiment, the target particle size D50 is 1-20 μm;

[0019] In an alternative embodiment, the target particle size D50 is 1-10 μm.

[0020] In a preferred embodiment of the present invention, the precipitant is sodium hydroxide or potassium hydroxide solution, the temperature of the reaction kettle is controlled to be 30-70°C, the speed of the reaction kettle is controlled to be 250-500r / min, and the inert gas is nitrogen or argon;

[0021] In an optional embodiment, the temperature of the reactor is controlled at 60-65°C.

[0022] In a preferred embodiment of the present invention, the inert gas is nitrogen and the precipitant is sodium hydroxide solution. The inert gas can protect Fe 2+ To prevent it from being oxidized to Fe 3+ , leading to Ni 2+ , Mn 2+ Precipitation occurs, resulting in pellets.

[0023] In a preferred embodiment of the present invention, the molar ratio of nickel, iron and manganese in the mixed metal salt solution can be any ratio, that is, the chemical formula Ni x Fe y Mn 1-x-y The value of x in (OH)2 can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8 or 0.9, and the value of y can be 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8 or 0.9, etc. For example, the molar ratio of nickel element, iron element and manganese element is 0.20:0.40:0.40, 0.28:0.36:0.36 or 0.10:0.30:0.60.

[0024] In an optional embodiment, after the particle size of the product reaches the target particle size, the product is subjected to aging, centrifugation, drying, sieving and demagnetization operations in sequence.

[0025] In the second aspect, the present invention also provides a method for preparing a nickel-iron-manganese ternary precursor for a sodium ion battery, wherein the particle size D50 of the precursor is 1-20 μm. The nickel-iron-manganese ternary precursor has good sphericity, adjustable primary particle morphology, and is very suitable for industrial mass production. The method has general applicability and is suitable for the preparation of other nickel-iron-manganese ternary precursors of different sizes and different proportions, and the sodium ion battery layered oxide positive electrode material prepared therefrom has excellent electrochemical performance.

[0026] In a third aspect, the present invention also provides a method for preparing a nickel-iron-manganese layered oxide material, which comprises the following steps: uniformly mixing the nickel-iron-manganese ternary precursor prepared by the method for preparing the nickel-iron-manganese ternary precursor for sodium ion battery with a sodium source and then calcining the mixture to obtain a nickel-iron-manganese layered oxide material Na(Ni x Fe y Mn 1-x-y )O2,(0 <x<1,0<y<1)。

[0027] In a fourth aspect, the present invention further provides an electrode material for a sodium ion battery, the electrode material comprising: a nickel-iron-manganese layered oxide material obtained by the above-mentioned method for preparing the nickel-iron-manganese layered oxide material.

[0028] In a fifth aspect, the present invention further provides a sodium ion battery, which comprises a positive electrode sheet made from the above-mentioned sodium ion battery electrode material.

[0029] The present invention has the following beneficial effects:

[0030] The preparation method of the nickel-iron-manganese ternary precursor provided by the present invention does not need to add additional reducing agents or dilute the feed liquid during the preparation process, and can control the nickel-iron-manganese ternary precursor to basically not produce small balls during the growth process, can smoothly grow to the required target particle size, and can achieve effective regulation of the primary particle morphology, with good sphericity, which is conducive to industrial mass production.

[0031] The inventors found that the morphology of the primary particles of the product can be effectively controlled by adjusting the pH and oxalate concentration of the reaction system. The morphology of the primary particles can be strip-shaped, thin strip-shaped, thick strip-shaped or flake-shaped.

[0032] Choosing oxalic acid has the following advantages: oxalic acid has certain reducing properties and can complex nickel, iron and manganese ions at the same time. Therefore, there is no need to add additional reducing agents during the preparation of the ternary precursor. The nickel, iron and manganese ternary precursor can be controlled to basically not produce small balls during the growth process, maintain a normal increase in particle size, and can grow smoothly to the required target particle size, which is suitable for industrial mass production.

[0033] In addition, the method provided by the present invention has universal applicability and is suitable for the preparation of other nickel-iron-manganese ternary precursors of different sizes and different proportions, and the sodium ion battery layered oxide positive electrode material prepared using the nickel-iron-manganese ternary precursor has excellent electrochemical performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0035] Figure 1 The figure is a flow chart for the preparation of nickel-iron-manganese ternary precursor;

[0036] Figure 2 This is a SEM image of the nickel-iron-manganese ternary precursor prepared in Example 1;

[0037] Figure 3 This is a SEM image of the nickel-iron-manganese ternary precursor prepared in Example 2;

[0038] Figure 4 This is a SEM image of the nickel-iron-manganese ternary precursor prepared in Example 3;

[0039] Figure 5 This is a SEM image of the nickel-iron-manganese ternary precursor prepared in Example 4;

[0040] Figure 6 This is a SEM image of the nickel-iron-manganese ternary precursor prepared in Example 5;

[0041] Figure 7 This is a SEM image of the nickel-iron-manganese ternary precursor prepared in Comparative Example 1;

[0042] Figure 8 This is a SEM image of the nickel-iron-manganese ternary precursor prepared in Comparative Example 2;

[0043] Fig. 9 This is a SEM image of the positive electrode material corresponding to the nickel-iron-manganese ternary precursor prepared in Example 1;

[0044] Fig.10 This is the electrochemical performance diagram of the positive electrode material corresponding to the nickel-iron-manganese ternary precursor prepared in Example 1. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0046] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0047] Example 1

[0048] This embodiment provides a method for preparing a nickel-iron-manganese ternary precursor. The specific flow chart is shown in Figure 1 As shown, the specific preparation method is as follows:

[0049] S1: Add pure water to the reactor and heat it to 60°C, then add the prepared oxalic acid solution to adjust the bottom liquid oxalate to 0.125 mol / L, then add the prepared liquid alkali solution to adjust the bottom liquid pH to 11.50, stir the paddles inside the reactor at a speed of 500 r / min to mix evenly, and prepare the bottom liquid for the coprecipitation reaction.

[0050] S2: Pump 2.0 mol / L nickel-iron-manganese mixed salt solution, 11.0 mol / L liquid alkali solution and 1.0 mol / L oxalic acid solution into the reactor at the same time, control the molar ratio of nickel-iron-manganese to be 28:36:36, and react for 0.5 hour under the conditions of maintaining the pH value of the reactor at 11.50 and the oxalate ion at 0.125 mol / L to complete the nucleation task.

[0051] S3: After completing the nucleation task, the process is switched to the growth process, gradually reducing the pH value of the reactor to 11.20, increasing the oxalate concentration to 0.175 mol / L, maintaining the temperature at 60°C, and continuing the reaction until the particle size of the product reaches 10.0 μm.

[0052] S4: The slurry is pumped into the aging tank through the discharge port. The obtained product is aged, centrifuged, dried, screened, iron-removed and packaged to obtain the nickel-iron-manganese ternary precursor. The scanning electron microscope image is as follows: Figure 2 shown.

[0053] Depend on Figure 2 It can be seen that the large particle (10 μm) nickel-iron-manganese (NFM) ternary precursor prepared in this embodiment basically does not produce small balls during the growth process and can smoothly grow to the target particle size of 10 μm, has good sphericity, and the primary particle morphology is strip-shaped.

[0054] Example 2

[0055] This embodiment provides a method for preparing a nickel-iron-manganese ternary precursor, and the specific preparation method is as follows:

[0056] S1: Add pure water to the reactor and heat it to 60°C, then add the prepared oxalic acid solution to adjust the bottom liquid oxalate to 0.30 mol / L, then add the prepared liquid alkali solution to adjust the bottom liquid pH to 11.50, stir the paddles inside the reactor at a speed of 500 r / min to mix evenly, and prepare the bottom liquid for the coprecipitation reaction.

[0057] S2: Pump 2.0 mol / L nickel-iron-manganese mixed salt solution, 11.0 mol / L liquid alkali solution and 1.0 mol / L oxalic acid solution into the reactor at the same time, control the molar ratio of nickel-iron-manganese to be 28:36:36, and react for 0.5 hour under the conditions of maintaining the pH value of the reactor at 11.50 and the oxalate ion at 0.30 mol / L to complete the nucleation task.

[0058] S3: After completing the nucleation task, the process is switched to the growth process, gradually reducing the pH value of the reactor to 11.20, increasing the oxalate concentration to 0.35 mol / L, maintaining the temperature at 60°C, and continuing the reaction until the particle size of the product reaches 10.0 μm.

[0059] S4: The slurry is pumped into the aging tank through the discharge port. The obtained product is aged, centrifuged, dried, screened, iron-removed and packaged to obtain the nickel-iron-manganese ternary precursor. The scanning electron microscope image is as follows: Figure 3 shown.

[0060] Depend on Figure 3 It can be seen that the large particle (10 μm) nickel-iron-manganese (NFM) ternary precursor prepared in this embodiment basically does not produce small balls during the growth process and can smoothly grow to the target particle size of 10 μm, has good sphericity, and the primary particle morphology is thin strips.

[0061] Example 3

[0062] This embodiment provides a method for preparing a nickel-iron-manganese ternary precursor, and the specific preparation method is as follows:

[0063] S1: Add pure water to the reactor and heat it to 60°C, then add the prepared oxalic acid solution to adjust the bottom liquid oxalate to 0.30 mol / L, then add the prepared liquid alkali solution to adjust the bottom liquid pH to 11.10, stir the paddles inside the reactor at a speed of 500 r / min to mix evenly, and prepare the bottom liquid for the coprecipitation reaction.

[0064] S2: Pump 2.0 mol / L nickel-iron-manganese mixed salt solution, 11.0 mol / L liquid alkali solution and 1.0 mol / L oxalic acid solution into the reactor at the same time, control the molar ratio of nickel-iron-manganese to be 28:36:36, and react for 0.5 hour under the conditions of maintaining the pH value of the reactor at 11.10 and the oxalate ion at 0.30 mol / L to complete the nucleation task.

[0065] S3: After completing the nucleation task, the process is switched to the growth process, gradually reducing the pH value of the reactor to 10.80, increasing the oxalate concentration to 0.35 mol / L, maintaining the temperature at 60°C, and continuing the reaction until the particle size of the product reaches 10.0 μm.

[0066] S4: The slurry is pumped into the aging tank through the discharge port. The obtained product is aged, centrifuged, dried, screened, iron-removed and packaged to obtain the nickel-iron-manganese ternary precursor. The scanning electron microscope image is as follows: Figure 4 shown.

[0067] Depend on Figure 4 It can be seen that the large particle (10 μm) nickel-iron-manganese (NFM) ternary precursor prepared in this embodiment basically does not produce small balls during the growth process and can smoothly grow to the target particle size of 10 μm, has good sphericity, and the primary particle morphology is flaky.

[0068] Example 4

[0069] This embodiment provides a method for preparing a nickel-iron-manganese ternary precursor, and the specific preparation method is as follows:

[0070] S1: Add pure water to the reactor and heat it to 60°C, then add the prepared oxalic acid solution to adjust the bottom liquid oxalate to 0.30 mol / L, then add the prepared liquid alkali solution to adjust the bottom liquid pH to 11.50, stir the paddles inside the reactor at a speed of 500 r / min to mix evenly, and prepare the bottom liquid for the coprecipitation reaction.

[0071] S2: Pump 2.0 mol / L nickel-iron-manganese mixed salt solution, 11.0 mol / L liquid alkali solution and 1.0 mol / L oxalic acid solution into the reactor at the same time, control the molar ratio of nickel-iron-manganese to be 10:30:60, and react for 0.5 hour under the conditions of maintaining the pH value of the reactor at 11.50 and the oxalate ion at 0.30 mol / L to complete the nucleation task.

[0072] S3: After completing the nucleation task, the process is switched to the growth process, gradually reducing the pH value of the reactor to 11.20, increasing the oxalate concentration to 0.35 mol / L, maintaining the temperature at 60°C, and continuing the reaction until the particle size of the product reaches 10.0 μm.

[0073] S4: The slurry is pumped into the aging tank through the discharge port. The obtained product is aged, centrifuged, dried, screened, iron-removed and packaged to obtain the nickel-iron-manganese ternary precursor. The scanning electron microscope image is as follows: Figure 5 shown.

[0074] Depend on Figure 5It can be seen that the large-particle (10 μm) nickel-iron-manganese (NFM) ternary precursor prepared in this embodiment basically does not produce small balls during the growth process and can smoothly grow to the target particle size of 10 μm, has good sphericity, and the primary particle morphology is coarse strips.

[0075] Example 5

[0076] This embodiment provides a method for preparing a nickel-iron-manganese ternary precursor, and the specific preparation method is as follows:

[0077] S1: Add pure water to the reactor and heat it to 60°C, then add the prepared oxalic acid solution to adjust the bottom liquid oxalate to 0.30 mol / L, then add the prepared liquid alkali solution to adjust the bottom liquid pH to 11.50, stir the paddles inside the reactor at a speed of 500 r / min to mix evenly, and prepare the bottom liquid for the coprecipitation reaction.

[0078] S2: Pump 2.0 mol / L nickel-iron-manganese mixed salt solution, 11.0 mol / L liquid alkali solution and 1.0 mol / L oxalic acid solution into the reactor at the same time, control the molar ratio of nickel-iron-manganese to be 20:40:40, and react for 0.5 hour under the conditions of maintaining the pH value of the reactor at 11.50 and the oxalate ion at 0.30 mol / L to complete the nucleation task.

[0079] S3: After completing the nucleation task, the process is switched to the growth process, gradually reducing the pH value of the reactor to 11.20, increasing the oxalate concentration to 0.35 mol / L, maintaining the temperature at 60°C, and continuing the reaction until the particle size of the product reaches 10.0 μm.

[0080] S4: The slurry is pumped into the aging tank through the discharge port. The obtained product is aged, centrifuged, dried, screened, iron-removed and packaged to obtain the nickel-iron-manganese ternary precursor. The scanning electron microscope image is as follows: Figure 6 shown.

[0081] Depend on Figure 6 It can be seen that the large-particle (10 μm) nickel-iron-manganese (NFM) ternary precursor prepared in this embodiment basically does not produce small balls during the growth process and can smoothly grow to the target particle size of 10 μm, has good sphericity, and the primary particle morphology is coarse strips.

[0082] Comparative Example 1

[0083] This comparative example provides a method for preparing a nickel-iron-manganese ternary precursor. This comparative example uses ammonia water as a complexing agent. The specific preparation method is as follows:

[0084] S1: Add pure water to the reactor and heat it to 50°C, then add ammonia solution to adjust the bottom liquid ammonium to 0.20 mol / L, then add the prepared liquid alkali solution to adjust the pH value of the bottom liquid to 11.50, stir the paddle inside the reactor at a speed of 500 r / min to mix evenly, and prepare the bottom liquid for the coprecipitation reaction.

[0085] S2: 1.5 mol / L nickel-iron-manganese mixed salt solution, 6.0 mol / L liquid alkali solution and 5.0 mol / L ammonia solution were pumped into the reactor at the same time, and the molar ratio of nickel-iron-manganese was controlled to be 20:40:40. The reaction was carried out for 0.5 hours under the conditions of maintaining the pH value of the reactor at 11.50 and the ammonium radical at 0.20 mol / L to complete the nucleation task.

[0086] S3: After completing the nucleation task, the process is switched to the growth process, gradually reducing the pH value of the reactor to 10.80, increasing the ammonium radical to 0.30 mol / L, and increasing the temperature to 60°C, and continuing the reaction until the particle size of the product reaches 5.0 μm.

[0087] S4: After 5.0μm, the growth process was further adjusted by lowering the pH value of the reactor to 10.30, increasing the ammonium ion to 0.36mol / L, keeping the temperature constant, and continuing the reaction until the particle size of the product reached 10.0μm.

[0088] S5: The slurry is pumped into the aging tank through the discharge port. The obtained product is aged, centrifuged, dried, sieved, demagnetized and packaged to obtain the nickel-iron-manganese ternary precursor. The scanning electron microscope image is as follows: Figure 7 shown.

[0089] Depend on Figure 7 It can be seen that the large-particle (10 μm) nickel-iron-manganese (NFM) ternary precursor obtained after diluting the feed liquid in the ammonia system prepared in this comparative example basically does not produce small balls during the growth process and can smoothly grow to the target particle size of 10 μm, with good sphericity and a flaky morphology of the primary particles.

[0090] Comparative Example 2

[0091] Compared with Comparative Example 1, the only difference is that there is no dilution liquid treatment and step S4 adjustment process. The prepared large particle (10 μm) nickel iron manganese (NFM) ternary precursor has a large number of small balls generated during the growth process, and the primary particles are severely "powdered". The particle size of the final product is only about 7 μm, and it cannot grow to the target particle size of 10 μm. The scanning electron microscope image is as follows Figure 8 shown.

[0092] Experimental Example 1

[0093] Experimental electrochemical performance of layered oxide cathode materials for sodium-ion batteries.

[0094] The inventor prepared the nickel-iron-manganese layered hydroxide precursor prepared in Example 1 as a positive electrode material. The specific preparation method is as follows: the nickel-iron-manganese ternary precursor obtained in Example 1 is completely and evenly mixed with sodium hydroxide in a mortar, and calcined at 880° C. for 14 h to obtain a sodium ion battery positive electrode material Na(Ni 0.28 Fe 0.36 Mn 0.36 )O2, such as Fig. 9 As shown, the prepared cathode material was subjected to electrochemical performance testing at 2.0-4.05V and 0.2C. The results are shown in Fig.10 As shown, its discharge capacity is 130.2 mAh / g. Fig.10 It can be seen that the positive electrode material prepared based on the nickel-iron-manganese layered hydroxide precursor of the present invention has excellent electrochemical performance.

[0095] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a nickel-iron-manganese ternary precursor for a sodium ion battery, characterized in that: It includes the following steps: A mixed metal salt solution consisting of nickel salt, ferrous salt and manganese salt, a precipitant and a complexing agent are introduced into a reactor prepared with a base liquid to carry out a coprecipitation reaction, wherein the concentration of the mixed metal salt solution is controlled to be ≤2.0 mol / L, the concentration of the precipitant is ≤11.0 mol / L, and the concentration of the complexing agent is ≤1.0 mol / L, an inert gas is continuously introduced during the reaction, and the reaction is continued until the particle size of the product reaches a target particle size, wherein the complexing agent is an oxalic acid solution; and the reaction is continued until the particle size D50 of the product reaches a target particle size of 1.0-20.0 μm; In the granulation stage, the pH in the reactor is controlled to be the first pH value, and the concentration of oxalate ions is the first oxalate value. In the growth stage, the pH in the reactor is controlled to be the second pH value, and the concentration of oxalate ions is the second oxalate value, and 12.0 ≥ the first pH value > the second pH value ≥ 10.0, 0.01 mol / L ≤ the first oxalate value < the second oxalate value ≤ 0.35 mol / L; The mixed metal salt solution has the following general chemical formula: Ni x Fe y Mn 1-x-y (OH)2, wherein the value of x is 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8 or 0.9 and the value of y is 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8 or 0.

9.

2. The method for preparing a nickel-iron-manganese ternary precursor for a sodium ion battery according to claim 1, characterized in that: The precipitant is sodium hydroxide or potassium hydroxide solution, the temperature of the reaction kettle is controlled to be 30-70° C., the rotation speed of the reaction kettle is controlled to be 250-500 r / min, and the inert gas is nitrogen or argon.

3. The method for preparing a nickel-iron-manganese ternary precursor for a sodium ion battery according to claim 2, characterized in that: The temperature of the reactor was controlled at 60-65°C.

4. The method for preparing a nickel-iron-manganese ternary precursor for a sodium ion battery according to claim 2, characterized in that: The inert gas is nitrogen, and the precipitant is sodium hydroxide solution.

5. The method for preparing a nickel-iron-manganese ternary precursor for a sodium ion battery according to claim 1, characterized in that: After the particle size of the product reaches the target particle size, the product is subjected to aging, centrifugation, drying, screening and demagnetization operations in sequence.

6. A nickel-iron-manganese ternary precursor prepared by the method for preparing a nickel-iron-manganese ternary precursor for a sodium ion battery according to any one of claims 1 to 5, characterized in that: The particle size D50 of the precursor is 1-20 μm.

7. A method for preparing a nickel-iron-manganese layered oxide material, characterized in that: The method comprises the following steps: uniformly mixing the nickel-iron-manganese ternary precursor prepared by the method for preparing the nickel-iron-manganese ternary precursor for sodium ion battery according to any one of claims 1 to 5 with a sodium source and then calcining the mixture to obtain a nickel-iron-manganese layered oxide material Na(Ni x Fe y Mn 1-x-y )O2,0 <x<1,0<y<1。 8. An electrode material for a sodium ion battery, characterized in that: The electrode material comprises: the nickel-iron-manganese layered oxide material obtained by the preparation method of the nickel-iron-manganese layered oxide material according to claim 7.

9. A sodium ion battery, characterized in that: It comprises a positive electrode sheet made from the electrode material of the sodium ion battery according to claim 8.

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