Nickel-iron-manganese-copper-sodium electric precursor material and preparation method and application thereof

Abstract

The invention provides a nickel-iron-manganese-copper-sodium electric precursor material and a preparation method and application thereof, and the preparation method comprises the following steps: carrying out a co-precipitation reaction on a ferrous source solution, a nickel-manganese-copper mixed salt solution, a precipitator solution and a complexing agent solution to obtain the nickel-iron-manganese-copper-sodium electric precursor material, the ferrous source solution comprises inorganic acid; the co-precipitation reaction comprises a seed crystal preparation stage and a particle growth stage which are carried out in sequence, and in the particle growth stage, the rotating speed of the reaction is reduced along with the increase of the particle size. According to the preparation method, the inorganic acid is added into the ferrous source solution, so that oxidation is prevented, the morphology of the precursor material is improved, introduction of excessive impurities is avoided, and material growth is further controlled in combination with the relationship between the particle size and the rotating speed, so that the morphology of the material is further improved, and the electrochemical performance of the material is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of batteries and relates to a nickel-iron-manganese-copper-sodium electric precursor material and a preparation method and application thereof. Background Art

[0002] Sodium-ion batteries (SIBs) hold great promise for large-scale energy storage due to their safety, excellent cycling performance, and widespread sodium resource availability. Furthermore, among SIB cathode materials, layered transition metal oxides (LTMs) are among the most promising due to their safety, high abundance, low cost, wide transition metal ion selectivity, and simple preparation methods.

[0003] The performance of layered transition metal oxide cathode materials depends critically on the preparation process of their precursors. The different morphologies and structures of these precursors significantly impact the cathode material and the resulting electrochemical properties. Furthermore, sulfur impurities are introduced during the co-precipitation process, negatively impacting the performance of sodium-ion batteries.

[0004] Based on the above research, it is necessary to provide a method for preparing sodium battery precursor materials, which can control the morphology of the precursor materials, reduce the impurity content in the materials, and improve the electrochemical performance of sodium ion batteries. Summary of the Invention

[0005] The purpose of the present invention is to provide a nickel-iron-manganese-copper-sodium electrical precursor material and its preparation method and application. The preparation method adds an inorganic acid to the ferrous source solution to prevent oxidation, improve the morphology of the precursor material, and avoid introducing too many impurities. At the same time, combined with the relationship between particle size and rotation speed, the material growth is further controlled, thereby further improving the morphology of the material and enhancing the electrochemical properties of the material.

[0006] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0007] In a first aspect, the present invention provides a method for preparing a nickel-iron-manganese-copper-sodium electrical precursor material, the preparation method comprising the following steps:

[0008] The ferrous source solution, the nickel-manganese-copper mixed salt solution, the precipitant solution and the complexing agent solution are subjected to a coprecipitation reaction to obtain the nickel-iron-manganese-copper sodium electrical precursor material;

[0009] The ferrous source solution includes an inorganic acid; the coprecipitation reaction includes a seed preparation stage and a particle growth stage performed sequentially, and in the particle growth stage, the reaction speed decreases as the particle size increases.

[0010] The present invention controls the pH of the ferrous source solution by adding an inorganic acid to the ferrous source solution, thereby preventing the oxidation of ferrous ions and promoting the coprecipitation of nickel, iron, manganese and copper, thereby improving the morphology and impurity content of the precursor material. In addition, the present invention controls the reaction rotation speed to decrease as the particle size increases during the particle growth stage, thereby effectively controlling the particle size and particle size distribution, and helping to maintain the uniformity of the reaction system and promoting uniform particle growth, thereby improving the particle size and morphology and improving the electrochemical properties of the precursor material.

[0011] Preferably, the pH of the ferrous source solution is 1.5-2.5, for example, 1.5, 1.7, 1.9, 2.1, 2.3 or 2.5, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0012] Preferably, the concentration of the ferrous source in the ferrous source solution is 60-70 g / L, for example, it can be 60 g / L, 62 g / L, 64 g / L, 66 g / L, 68 g / L or 70 g / L, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0013] Preferably, the inorganic acid comprises dilute sulfuric acid.

[0014] The present invention adopts dilute sulfuric acid to adjust the pH of the ferrous source solution, and will not introduce more impurities into the system.

[0015] Preferably, the mass fraction of the dilute sulfuric acid is ≤10%, for example, it can be 10%, 9%, 8%, 7%, 6%, 5%, 4% or 3%, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0016] Preferably, during the particle growth stage, the reaction speed decreases by 10-20 rpm, for example, 10 rpm, 12 rpm, 14 rpm, 16 rpm, 18 rpm or 20 rpm, for every 0.5-1.5 μm increase in particle size, for example, 0.5 μm, 0.7 μm, 0.9 μm, 1.1 μm, 1.3 μm or 1.5 μm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0017] The present invention controls the relationship between the growth rate of particle size and the rotation speed during the particle growth stage, which can promote uniform growth of particles, thereby improving the morphology of particles, reducing the risk of particle breakage, and is also beneficial to the orderly deposition of ions, promoting dense and uniform growth of particles, and reducing the generation of defects.

[0018] Preferably, the rotation speed in the seed crystal preparation stage is greater than the rotation speed in the particle growth stage.

[0019] The rotation speed in the seed crystal preparation stage of the present invention is greater than the rotation speed in the particle growth stage, ensuring that substances such as metal salts and precipitants are quickly and evenly dispersed, avoiding excessive local concentration, obtaining fine crystal seeds with uniform size and good dispersion, and preventing the collision and agglomeration of primary grains, maintaining monodispersity, and providing a high-quality template for subsequent particle growth.

[0020] Preferably, the rotation speed in the seed crystal preparation stage is 400-700 rpm, for example, 400 rpm, 500 rpm, 600 rpm or 700 rpm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0021] Preferably, the seed crystal preparation stage adopts an overflow reaction method.

[0022] The seed crystal preparation stage of the present invention adopts an overflow method to carry out the reaction, which can maintain a stable supersaturation of the reaction, improve the uniformity of the seed crystal size, avoid local supersaturation, prevent local explosive nucleation and reduce the generation of fine crystals.

[0023] Preferably, the particle size D50 of the seed crystals obtained in the seed crystal preparation stage is 2-5 μm, for example, it can be 2 μm, 2.5 μm, 3 μm, 3.5 μm, 4 μm, 4.5 μm or 5 μm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0024] Preferably, the pH of the coprecipitation reaction is 9-11, for example, 9.3, 9.5, 9.7, 9.9, 10.1 or 11, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0025] Preferably, in the coprecipitation reaction system, the concentration of the complexing agent is 3.5-9.0 g / L, for example, 3.5 g / L, 4.0 g / L, 5.0 g / L, 6.0 g / L, 7.0 g / L, 8.0 g / L or 9.0 g / L, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0026] Preferably, the temperature of the coprecipitation reaction is 40°C-70°C, for example, 40°C, 50°C, 60°C or 70°C, and the particle size D50 of the target product is 10-18 μm, for example, 10 μm, 11 μm, 12 μm, 13 μm, 14 μm, 15 μm, 16 μm, 17 μm or 18 μm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0027] Preferably, the ferrous source solution, nickel-manganese-copper mixed salt solution, precipitant solution and complexing agent solution are introduced into the base liquid to carry out a coprecipitation reaction. The pH of the base liquid is 10.5-11.5, for example, it can be 10.5, 10.7, 10.9, 11.1, 11.3 or 11.5, and the concentration of the complexing agent is 10-30 g / L, for example, it can be 10 g / L, 15 g / L, 20 g / L, 25 g / L or 30 g / L, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable.

[0028] Preferably, the total metal ion concentration of the nickel-manganese-copper mixed salt solution is 1 mol / L-3 mol / L, for example, it can be 1 mol / L, 2 mol / L or 3 mol / L, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0029] Preferably, the mass concentration of the precipitant solution is 25-35 wt%, for example, 25 wt%, 30 wt% or 35 wt%, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0030] Preferably, the mass concentration of the complexing agent solution is 15-20wt%, for example, 15wt%, 17wt%, 19wt% or 20wt%, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0031] In a second aspect, the present invention provides a nickel-iron-manganese-copper-sodium electrical precursor material, which is prepared by the preparation method described in the first aspect.

[0032] Preferably, in the nickel-iron-manganese-copper-sodium electrical precursor material, the molar ratio of nickel ions, iron ions, manganese ions and copper ions is a:b:c:d, wherein 0.2≤a≤0.6, for example, it can be 0.2, 0.3, 0.4, 0.5 or 0.6, 0.2≤b≤0.6, for example, it can be 0.2, 0.3, 0.4, 0.5 or 0.6, 0.2≤c≤0.6, for example, it can be 0.2, 0.3, 0.4, 0.5 or 0.6, 0<d≤0.02, for example, it can be 0.005, 0.01, 0.015 or 0.02, and a+b+c+d=1.

[0033] In a third aspect, the present invention provides a nickel-iron-manganese-copper-sodium cathode material, which is obtained by mixing and sintering a sodium source and the nickel-iron-manganese-copper-sodium cathode material as described in the second aspect.

[0034] In a fourth aspect, the present invention provides a sodium ion battery, comprising the nickel-iron-manganese-copper-sodium cathode material as described in the third aspect.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] The present invention controls the pH of the ferrous source solution by adding an inorganic acid to the ferrous source solution, thereby preventing the oxidation of ferrous ions and promoting the coprecipitation of nickel, iron, manganese and copper, thereby improving the morphology and impurity content of the precursor material. In addition, the present invention controls the reaction rotation speed to decrease as the particle size increases during the particle growth stage, thereby effectively controlling the particle size and particle size distribution, and helping to maintain the uniformity of the reaction system and promoting uniform particle growth, thereby improving the particle size and morphology and improving the electrochemical properties of the precursor material. DETAILED DESCRIPTION

[0037] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0038] Example 1

[0039] This embodiment provides a method for preparing a nickel-iron-manganese-copper-sodium electrical precursor material, the preparation method comprising the following steps:

[0040] (1) Ferrous sulfate, dilute sulfuric acid (8% by mass) and water are prepared into a ferrous source solution with a pH of 2.0 and a ferrous sulfate concentration of 65 g / L; nickel sulfate, manganese sulfate and copper sulfate are used to prepare a nickel-manganese-copper mixed salt solution with a total metal ion concentration of 2 mol / L; and a sodium hydroxide solution with a mass concentration of 30 wt% and an ammonia solution with a mass concentration of 18 wt% are simultaneously prepared;

[0041] (2) A bottom solution with a pH of 11.0 and an ammonia concentration of 20 g / L was added to the reactor, and a ferrous source solution, a nickel-manganese-copper mixed salt solution, a sodium hydroxide solution and an ammonia solution were introduced into the bottom solution to carry out a coprecipitation reaction. The pH of the coprecipitation reaction was 9.5-10.0, the ammonia concentration was 4.5-5.0 g / L, and the temperature was 60°C. The coprecipitation reaction was divided into a seed preparation stage and a particle growth stage, which were carried out in sequence. The rotation speed of the seed preparation stage was 500 rpm, and react in an overflow manner to obtain seed crystals with a particle size D50 of 3 μm, then reduce the speed to enter the particle growth stage, wherein the speed is reduced by 15 rpm for every 1 μm increase in the particle size, and react until the particle size D50 of the product is 15 μm, and then wash with cold water to obtain the nickel-iron-manganese-copper-sodium electric precursor material, wherein the molar ratio of nickel ions, iron ions, manganese ions and copper ions in the nickel-iron-manganese-copper-sodium electric precursor material is 0.3:0.49:0.2:0.01.

[0042] Example 2

[0043] This embodiment provides a method for preparing a nickel-iron-manganese-copper-sodium electrical precursor material, the preparation method comprising the following steps:

[0044] (1) Ferrous sulfate, dilute sulfuric acid (mass fraction 10%) and water are prepared into a ferrous source solution with a pH of 2.5 and a ferrous sulfate concentration of 60 g / L; nickel sulfate, manganese sulfate and copper sulfate are used to prepare a nickel-manganese-copper mixed salt solution with a total metal ion concentration of 3 mol / L; and a sodium hydroxide solution with a mass concentration of 25 wt% and an ammonia solution with a mass concentration of 20 wt% are prepared at the same time;

[0045] (2) A bottom liquid with a pH of 10.5 and an ammonia concentration of 30 g / L was added to the reactor, and a ferrous source solution, a nickel-manganese-copper mixed salt solution, a sodium hydroxide solution, and an ammonia solution were introduced into the bottom liquid to perform a coprecipitation reaction. The pH of the coprecipitation reaction was 9.3-9.5, the ammonia concentration was 4.0-4.5 g / L, and the temperature was 70°C. The coprecipitation reaction was divided into a seed preparation stage and a particle growth stage, which were carried out in sequence. The rotation speed of the seed preparation stage was 700 rpm. m, and react in an overflow manner to obtain seed crystals with a particle size D50 of 2 μm, then reduce the rotation speed to enter the particle growth stage, wherein the rotation speed is reduced by 20 rpm every time the particles increase by 0.5 μm, and react until the particle size D50 of the product is 10 μm, and then wash with cold water to obtain the nickel-iron-manganese-copper-sodium electric precursor material, wherein the molar ratio of nickel ions, iron ions, manganese ions and copper ions in the nickel-iron-manganese-copper-sodium electric precursor material is 0.2:0.58:0.2:0.02.

[0046] Example 3

[0047] This embodiment provides a method for preparing a nickel-iron-manganese-copper-sodium electrical precursor material, the preparation method comprising the following steps:

[0048] (1) Ferrous sulfate, dilute sulfuric acid (mass fraction 10%) and water are prepared into a ferrous source solution with a pH of 1.5 and a ferrous sulfate concentration of 70 g / L; nickel sulfate, manganese sulfate and copper sulfate are used to prepare a nickel-manganese-copper mixed salt solution with a total metal ion concentration of 1 mol / L; and a sodium hydroxide solution with a mass concentration of 35 wt% and an ammonia solution with a mass concentration of 15 wt% are prepared at the same time;

[0049] (2) A bottom solution with a pH of 11.5 and an ammonia concentration of 10 g / L was added to the reactor, and a ferrous source solution, a nickel-manganese-copper mixed salt solution, a sodium hydroxide solution and an ammonia solution were introduced into the bottom solution to carry out a coprecipitation reaction. The pH of the coprecipitation reaction was 10.0-10.3, the ammonia concentration was 8.0-8.5 g / L, and the temperature was 40°C. The coprecipitation reaction was divided into a seed preparation stage and a particle growth stage, which were carried out in sequence. The rotation speed of the seed preparation stage was 400 r pm, and react in an overflow manner to obtain seed crystals with a particle size D50 of 4 μm, then reduce the rotation speed to enter the particle growth stage, wherein the rotation speed is reduced by 10 rpm every time the particles increase by 1.5 μm, and react until the particle size D50 of the product is 18 μm, and then wash with cold water to obtain the nickel-iron-manganese-copper-sodium electric precursor material, in which the molar ratio of nickel ions, iron ions, manganese ions and copper ions is 0.3:0.49:0.2:0.01.

[0050] Example 4

[0051] This embodiment provides a method for preparing a nickel-iron-manganese-copper-sodium electrical precursor material. The preparation method is the same as that of Example 1, except that in the particle growth stage described in step (2), the reaction speed is reduced by 15 rpm for every 3 μm increase in particle size.

[0052] Example 5

[0053] This embodiment provides a method for preparing a nickel-iron-manganese-copper-sodium electrical precursor material. The preparation method is the same as that of Example 1, except that in the particle growth stage described in step (2), the reaction speed is reduced by 15 rpm for every 0.3 μm increase in particle size.

[0054] Example 6

[0055] This embodiment provides a method for preparing a nickel-iron-manganese-copper-sodium electrical precursor material. The preparation method is the same as that of Example 1, except that in the particle growth stage described in step (2), the reaction speed is reduced by 5 rpm for every 1 μm increase in particle size.

[0056] Example 7

[0057] This embodiment provides a method for preparing a nickel-iron-manganese-copper-sodium electrical precursor material. The preparation method is the same as that of Example 1, except that in the particle growth stage described in step (2), the reaction speed is reduced by 30 rpm for every 1 μm increase in particle size.

[0058] Example 8

[0059] This embodiment provides a method for preparing a nickel-iron-manganese-copper-sodium electrical precursor material. The preparation method is the same as that of Example 1, except that the pH of the ferrous source solution in step (1) is 1.

[0060] Example 9

[0061] This embodiment provides a method for preparing a nickel-iron-manganese-copper-sodium electrical precursor material. The preparation method is the same as that of Example 1, except that the pH of the ferrous source solution in step (1) is 3.

[0062] Comparative Example 1

[0063] This comparative example provides a method for preparing a nickel-iron-manganese-copper-sodium electrical precursor material. The preparation method is the same as Example 1, except that no dilute sulfuric acid is added to the ferrous source solution to adapt the pH of the ferrous source solution.

[0064] Comparative Example 2

[0065] This comparative example provides a method for preparing a nickel-iron-manganese-copper-sodium electrical precursor material. The preparation method is the same as Example 1, except that the rotation speed in the particle growth stage remains unchanged and is the same as the rotation speed in the seed crystal preparation stage.

[0066] The nickel-iron-manganese-copper-sodium precursor materials obtained in the above examples and comparative examples were mixed with sodium carbonate and sintered to prepare nickel-iron-manganese-copper-sodium cathode materials. The nickel-iron-manganese-copper-sodium cathode materials were prepared into cathode sheets, which were assembled with a sodium metal sheet, a polypropylene porous membrane, and an electrolyte to form a sodium ion battery for electrochemical performance testing. The electrolyte was 1 mol / L NaPF6 / EC+DEC+DMC (the volume ratio of EC, DEC, and DMC was 1:1:1). The sodium ion battery was subjected to first discharge specific capacity and 200 cycle performance testing.

[0067] The test results are shown in Table 1:

[0068] Table 1

[0069]

[0070] From Table 1 we can see that:

[0071] It can be seen from Example 1 and Comparative Example 1 that the present invention can avoid the oxidation of ferrous ions by adding an inorganic acid to the ferrous source solution to control the pH, promote the co-precipitation of nickel, iron, manganese and copper, and improve the morphology and impurity content of the precursor material, thereby improving the electrochemical performance of the sodium ion battery; It can be seen from Example 1 and Comparative Example 2 that the present invention controls the reaction speed to decrease with the increase of the particle size in the particle growth stage, which can improve the morphology of the particles, reduce the risk of particle breakage, and improve the electrochemical performance of the sodium ion battery; It can be seen from Example 1 and Examples 4-7 that the present invention controls the relationship between the increase rate and the rotation speed of the particle size, which can promote uniform growth of particles and improve the morphology of the precursor material; It can be seen from Example 1 and Examples 8-9 that the pH of the ferrous source solution of the present invention is preferably within a suitable range, which can further improve the electrochemical performance of the sodium ion battery.

[0072] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for preparing a nickel-iron-manganese-copper-sodium electrical precursor material, characterized in that: The preparation method comprises the following steps: The ferrous source solution, the nickel-manganese-copper mixed salt solution, the precipitant solution and the complexing agent solution are subjected to a coprecipitation reaction to obtain the nickel-iron-manganese-copper sodium electrical precursor material; The ferrous source solution includes an inorganic acid; the coprecipitation reaction includes a seed preparation stage and a particle growth stage performed sequentially, and in the particle growth stage, the reaction speed decreases as the particle size increases.

2. The preparation method according to claim 1, characterized in that The pH of the ferrous source solution is 1.5-2.5; Preferably, the concentration of the ferrous source in the ferrous source solution is 60-70 g / L.

3. The preparation method according to claim 1 or 2, characterized in that The inorganic acid includes dilute sulfuric acid; Preferably, the mass fraction of the dilute sulfuric acid is ≤10%.

4. The preparation method according to any one of claims 1 to 3, characterized in that During the particle growth stage, the reaction speed decreases by 10-20 rpm for every 0.5-1.5 μm increase in particle size; Preferably, the rotation speed in the seed crystal preparation stage is greater than the rotation speed in the particle growth stage.

5. The preparation method according to any one of claims 1 to 4, characterized in that The rotation speed during the seed crystal preparation stage is 400-700 rpm; Preferably, the seed crystal preparation stage adopts an overflow method to carry out the reaction; Preferably, the particle size D50 of the seed crystals obtained in the seed crystal preparation stage is 2-5 μm.

6. The preparation method according to any one of claims 1 to 5, characterized in that The pH of the coprecipitation reaction is 9-11; Preferably, in the coprecipitation reaction system, the concentration of the complexing agent is 3.5-9.0 g / L; Preferably, the temperature of the coprecipitation reaction is 40° C.-70° C., and the particle size D50 of the target product is 10-18 μm.

7. The preparation method according to any one of claims 1 to 6, characterized in that The ferrous source solution, nickel-manganese-copper mixed salt solution, precipitant solution and complexing agent solution are introduced into the base liquid to carry out a coprecipitation reaction, wherein the pH of the base liquid is 10.5-11.5 and the concentration of the complexing agent is 10-30 g / L; Preferably, the total metal ion concentration of the nickel-manganese-copper mixed salt solution is 1 mol / L-3 mol / L; Preferably, the mass concentration of the precipitant solution is 25-35wt%; Preferably, the mass concentration of the complexing agent solution is 15-20 wt%.

8. A nickel-iron-manganese-copper-sodium electrical precursor material, characterized in that: The nickel-iron-manganese-copper-sodium electrical precursor material is prepared by the preparation method according to any one of claims 1 to 7; Preferably, in the nickel-iron-manganese-copper-sodium electrical precursor material, the molar ratio of nickel ions, iron ions, manganese ions and copper ions is a:b:c:d, wherein 0.2≤a≤0.6, 0.2≤b≤0.6, 0.2≤c≤0.6, 0<d≤0.02, and a+b+c+d=1.

9. A nickel-iron-manganese-copper-sodium cathode material, characterized in that: The nickel-iron-manganese-copper-sodium cathode material is obtained by mixing and sintering a sodium source and the nickel-iron-manganese-copper-sodium cathode precursor material as claimed in claim 8.

10. A sodium ion battery, characterized in that: The sodium ion battery comprises the nickel-iron-manganese-copper-sodium cathode material as claimed in claim 9.

Images