Sodium battery precursor, and preparation method therefor and use thereof

Abstract

A sodium battery precursor, and a preparation method therefor and the use thereof. The preparation method comprises the following steps: (1) mixing a nickel salt, a manganese salt and an iron salt with a solvent to obtain a solution A, mixing a copper salt, a complexing agent and a solvent to obtain a solution B, and mixing one or more of a lithium salt, a zinc salt, a titanium salt or a magnesium salt with a solvent to obtain a solution C; (2) injecting an alkali liquor, ammonia water and the solution A into a base solution in parallel flow for a first-step co-precipitation reaction, and injecting ammonia water, the alkali liquor and the solution B in parallel flow for a second-step co-precipitation reaction; and (3) injecting a precipitant solution and the solution C in parallel flow for a third-step co-precipitation reaction, thereby obtaining the sodium battery precursor. A high-entropy superlattice sodium battery precursor is prepared by means of step-by-step co-precipitation, and the sodium battery precursor enables the improvement of the sodium-ion intercalation and de-intercalation capability of the precursor while reducing the material cost, thereby improving the capacity retention ratio and cycling performance of the material.

Description

A sodium electrode precursor and its preparation method and application Technical Field

[0001] The present application relates to the technical field of sodium ion batteries, for example, a sodium battery precursor and its preparation method and application. Background Art

[0002] In today's energy shortage, the healthy and orderly development of new energy storage batteries such as lithium-ion batteries and sodium-ion batteries is particularly important. This is accompanied by the country's increasing requirements for the energy density of power batteries and the urgent hope that sodium-ion batteries will enter the market early to alleviate energy storage pressure. Currently, the energy density of sodium-ion batteries is relatively low. Although layered oxide cathode materials have a high theoretical capacity, increasing the charge cutoff voltage will lead to problems such as metal dissolution and electrolyte decomposition. Therefore, it is necessary to research methods that can maximize capacity, effectively inhibit electrolyte decomposition, and reduce metal dissolution within the existing voltage range.

[0003] Compared with lithium-ion batteries, sodium-ion batteries have the advantages of low raw material costs and large reserves, and have great advantages in chemical energy storage, low-speed electric vehicles, base station construction, etc.

[0004] CN113644268A discloses a sodium ion battery layered cathode material and a preparation method thereof, wherein a sodium source material and an M source material are ball-milled and mixed under inert gas protection to form powder, and then calcined at high temperature to form Na x The MO2 layered material is then ground into a composite powder, and the composite powder is stirred and mixed with a doping coating salt solution under heating until the solvent is completely evaporated to obtain a coated doped powder. The obtained coated doped powder is calcined again and cooled to obtain a sodium ion battery layered positive electrode material.

[0005] CN115207352A discloses a sodium ion battery cathode material, a preparation method thereof, and a sodium ion battery. The sodium ion battery cathode material has a layered structure and is co-doped with metal elements and sulfur elements.

[0006] The layered sodium ion battery positive electrode material prepared by the above scheme will cause the capacity and voltage to decay rapidly during the charge and discharge process due to its layered structure, which affects its practical application.

[0007] Summary of the Invention

[0008] 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.

[0009] The present application provides a sodium battery precursor, a preparation method and an application thereof. The present application can prepare a high-entropy superlattice sodium battery precursor by a step-by-step co-precipitation method and rationally adding doping raw materials in steps. The sodium battery precursor can reduce material costs while improving the sodium ion deintercalation ability of the precursor due to its unique layered structure, thereby improving the capacity retention rate and cycle performance of the material.

[0010] In a first aspect, the present application provides a method for preparing a sodium electrolyte precursor, the preparation method comprising the following steps:

[0011] (1) mixing a nickel salt, a manganese salt, and an iron salt with a solvent to obtain a solution A, mixing a copper salt, a complexing agent, and a solvent to obtain a solution B, and mixing one or more of a lithium salt, a zinc salt, a titanium salt, or a magnesium salt with a solvent to obtain a solution C;

[0012] (2) injecting alkali solution, ammonia water and solution A into the bottom liquid in parallel to perform a one-step coprecipitation reaction, and injecting ammonia water, alkali solution and solution B into the bottom liquid in parallel to perform a two-step coprecipitation reaction;

[0013] (3) Injecting the precipitant solution and solution C in parallel to perform a three-step co-precipitation reaction to obtain the sodium electrolyte precursor.

[0014] The method described in the present application can prepare a high-entropy oxide precursor by controlling the co-precipitation order of the base material and various doping raw materials. The high-entropy oxide precursor has the characteristics of shared crystallization sites, can stabilize the structure, improve the cycle performance, and reduce the problems of capacity and voltage attenuation.

[0015] In one embodiment, if the capacity performance of the material is required to be high, a lithium salt is added to solution C; if the cycle performance of the material is required to be high, a titanium salt is added to solution C.

[0016] In one embodiment, the nickel salt, manganese salt, iron salt, copper salt, zinc salt, titanium salt or magnesium salt in step (1) comprises sulfate, nitrate or chloride.

[0017] In one embodiment, the lithium source comprises lithium sulfate.

[0018] In one embodiment, the complexing agent includes any one of ammonia water, acetic acid, sodium citrate or ethylenediamine, or a combination of at least two thereof.

[0019] In one embodiment, the mass concentration of the complexing agent in the solution B is 2-5 g / L, for example, 2 g / L, 2.5 g / L, 3 g / L, 4 g / L or 5 g / L.

[0020] In one embodiment, the total metal molar concentration of the solution A is 1.6 to 2.4 mol / L, for example, 1.6 mol / L, 1.8 mol / L, 2 mol / L, 2.2 mol / L or 2.4 mol / L.

[0021] In one embodiment, the base liquid in step (2) includes ammonia water and alkali solution.

[0022] In one embodiment, the pH of the base solution is 9 to 13, for example, 9, 10, 11, 12 or 13.

[0023] In one embodiment, the ammonia concentration in the base solution is 1 to 10 g / L, for example, 1 g / L, 2 g / L, 5 g / L, 8 g / L or 10 g / L.

[0024] In one embodiment, the temperature of the base liquid is 40-100°C, for example, 40°C, 50°C, 60°C, 80°C or 100°C.

[0025] In one embodiment, the concentration of the alkali solution in step (2) is 9 to 12 mol / L, for example, 9 mol / L, 9.5 mol / L, 10 mol / L, 11 mol / L or 12 mol / L.

[0026] In one embodiment, the concentration of the ammonia solution is 7 to 10 mol / L, for example, 7 mol / L, 7.5 mol / L, 8 mol / L, 8.5 mol / L, 9 mol / L or 10 mol / L.

[0027] In one embodiment, the endpoint of the one-step coprecipitation reaction is that the particle size a in the system is 3 to 12 μm, for example, 3 μm, 6 μm, 8 μm, 10 μm or 12 μm.

[0028] In one embodiment, the particle size of the particles in the system after the two-step coprecipitation reaction in step (2) is b, ba = 0.8 to 3 μm, for example: 0.8 μm, 1 μm, 1.5 μm, 2 μm or 3 μm.

[0029] In one embodiment, the solute of the precipitant solution in step (3) includes sodium hydroxide and / or potassium hydroxide.

[0030] In one embodiment, the concentration of the precipitant solution is 0.8 to 1.2 mol / L, for example, 0.8 mol / L, 0.9 mol / L, 1 mol / L, 1.1 mol / L or 1.2 mol / L.

[0031] In one embodiment, the time for the three-step co-precipitation in step (3) is 3 to 12 hours, for example: 3 hours, 4 hours, 5 hours, 8 hours or 12 hours.

[0032] In one embodiment, after the three-step coprecipitation reaction is completed, the particle size of the particles in the system is c, cb = 0.3 to 0.8 μm, for example: 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm or 0.8 μm.

[0033] In one embodiment, inert gas is introduced during the one-step co-precipitation reaction, the two-step co-precipitation reaction, and the three-step co-precipitation reaction.

[0034] In one embodiment, the temperature of the one-step coprecipitation reaction, the two-step coprecipitation reaction and the three-step coprecipitation reaction is 40-100°C, for example, 40°C, 50°C, 60°C, 80°C or 100°C.

[0035] In one embodiment, the stirring speed of the one-step co-precipitation reaction, the two-step co-precipitation reaction and the three-step co-precipitation reaction is 200-500 rpm, for example, 200 rpm, 250 rpm, 300 rpm, 400 rpm or 500 rpm.

[0036] In the second aspect, the present application provides a sodium-ion precursor, which is prepared by the method described in the first aspect, and the chemical formula of the sodium-ion precursor is Ni a Fe b Cu c Mn d Li e Zn x Ti y Mg z (OH)2, (a+b+c+d+e+x+y+z=1, and 0.05 <a<0.4,0.05<b<0.4,0.05<c<0.4,0.05<d<0.4,e<0.11,x<0.11,y<0.11,z<0.11)。

[0037] In the sodium battery precursor described in the present application, the cost is reduced by introducing low-priced metals such as copper and iron; zinc, titanium or magnesium are doped, and the sodium layer spacing is increased to make sodium ions easier to deintercalate and deintercalate, thereby enhancing the rate performance.

[0038] In a third aspect, the present application provides a positive electrode material, which is prepared by mixing and sintering the sodium electrode precursor and a sodium source as described in the second aspect.

[0039] In a fourth aspect, the present application provides a sodium ion battery, which comprises the positive electrode material as described in the third aspect.

[0040] Compared with the related art, this application has the following beneficial effects:

[0041] The present application uses a step-by-step co-precipitation method to rationally add doping raw materials in steps to prepare a high-entropy superlattice sodium electric precursor. The sodium electric precursor can reduce material costs while improving the sodium ion deintercalation ability of the precursor due to its unique layered structure, thereby improving the capacity retention rate and cycle performance of the material.

[0042] Still other aspects will become apparent upon reading and understanding the detailed description. DETAILED DESCRIPTION

[0043] 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.

[0044] Example 1

[0045] This embodiment provides a sodium battery precursor, and the preparation method of the sodium battery precursor is as follows:

[0046] (1) preparing a sulfate solution containing nickel ions, iron ions, and manganese ions with a total ion concentration of 2 mol / L, wherein the molar ratio of Ni:Fe:Mn is 1:1:1, to obtain a mixed solution A; preparing a sulfate solution containing a copper ion concentration of 2 mol / L, adding ammonia water (ammonia concentration maintained at 3 g / L) to obtain a mixed solution B; preparing a sulfate solution C with a titanium ion concentration of 2 mol / L; preparing a 10 mol / L alkaline solution; and preparing an 8 mol / L ammonia solution;

[0047] (2) Prepare a base solution with a pH of 11 and an ammonia concentration of 5 g / L, heat to 60°C, control the stirring speed to 300 rpm, continuously introduce inert gas, introduce alkali solution, ammonia water and solution A, and after the particle size grows to the target particle size D50 of 9 μm, inject ammonia water, alkali solution and solution B in parallel, and grow the particle size to the target particle size D50 of 9.42 μm;

[0048] (3) Injecting the precipitant solution, ammonia water and solution C in parallel until the particle size D50 is 9.55 μm to obtain the sodium battery precursor. The chemical formula of the sodium battery precursor is Ni 0.20 Fe 0.28 Mn 0.37 Cu 0.10 Ti 0.05 (OH)2.

[0049] Example 2

[0050] This embodiment provides a sodium battery precursor, and the preparation method of the sodium battery precursor is as follows:

[0051] (1) preparing a sulfate solution containing nickel ions, iron ions, and manganese ions with a total ion concentration of 2 mol / L, wherein the molar ratio of Ni:Fe:Mn is 1:1:1, to obtain a mixed solution A; preparing a sulfate solution containing a copper ion concentration of 2.3 mol / L, adding ammonia water (ammonia concentration maintained at 2-5 g / L) to obtain a mixed solution B; preparing a sulfate solution C with a lithium ion concentration of 2 mol / L; preparing a 9.8 mol / L alkaline solution; and preparing an 8.2 mol / L ammonia solution;

[0052] (2) Prepare a base solution with a pH of 11.2 and an ammonia concentration of 5.3 g / L, heat to 65°C, control the stirring speed to 350 rpm, continuously introduce inert gas, introduce alkali solution, ammonia water and solution A, and after the particle size grows to the target particle size D50 of 8 μm, inject ammonia water, alkali solution and solution B in parallel, and grow the particle size to the target particle size D50 of 8.45 μm;

[0053] (3) Injecting the precipitant solution, ammonia water and solution C in parallel until the particle size D50 is 8.48 μm to obtain the sodium battery precursor. The chemical formula of the sodium battery precursor is Ni 0.24 Fe 0.30 Mn 0.32 Cu 0.13 Li 0.1 (OH)2.

[0054] Comparative Example 1

[0055] The only difference between this comparative example and Example 1 is that various raw material solutions are introduced simultaneously to carry out the coprecipitation reaction, and other conditions and parameters are exactly the same as those in Example 1.

[0056] Comparative Example 2

[0057] The only difference between this comparative example and Example 1 is that no copper source is added, and other conditions and parameters are exactly the same as those in Example 1.

[0058] Comparative Example 3

[0059] The only difference between this comparative example and Example 1 is that no titanium source is added, and other conditions and parameters are exactly the same as those in Example 1.

[0060] Comparative Example 4

[0061] The only difference between this comparative example and Example 1 is that no copper source and titanium source are added, and other conditions and parameters are exactly the same as those in Example 1.

[0062] Comparative Example 5

[0063] The only difference between this comparative example and Example 1 is that the titanium source is added first and then the copper source is added. Other conditions and parameters are exactly the same as those in Example 1.

[0064] Performance testing:

[0065] The precursors obtained in the examples and comparative examples were pre-calcined at 400°C for 5 hours, then uniformly mixed with Na2CO3 powder according to the element ratio, and calcined in an air atmosphere at 800°C for 12 hours to obtain a sodium ion positive electrode material. The electrode material, acetylene black, and polyvinylidene fluoride were added dropwise to N-methyl-2-pyridine alkone in a mass ratio of 8:1:1 to prepare a solution, which was then evenly applied to aluminum foil, dried, and stamped into thin sheets. The battery pole piece, elemental sodium sheet, glass fiber separator, electrolyte (NaClO4) gasket, shrapnel, and battery shell were assembled into a button cell in an Ar gas glove box. The battery was subjected to performance testing, and the test results are shown in Table 1:

[0066] Table 1

[0067] As can be seen from Table 1, it can be obtained from Examples 1-2 that the battery made of the sodium battery precursor described in the present application not only reduces the cost while ensuring the discharge capacity of 0.2C, 0.5C and 1C, but also greatly improves the cycle performance. The capacity performance of the material can be improved by replacing the titanium salt with a lithium salt, but the cycle performance also decreases.

[0068] By comparing Example 1 and Comparative Example 1, it can be seen that the method described in the present application prepares a layered sodium battery precursor by a step-by-step co-precipitation method. The precursor reduces the problems of capacity and voltage attenuation due to its unique layered structure doped with multiple elements.

[0069] From the comparison between Example 1 and Comparative Example 2, it can be seen that the doping of zinc, titanium or magnesium in the present application can increase the sodium interlayer spacing, making it easier for sodium ions to be deintercalated and deintercalated, thereby enhancing the rate performance.

[0070] From the comparison between Example 1 and Comparative Example 3, it can be seen that the introduction of copper, a cheap metal, in the present application reduces the cost without significantly affecting the electrical properties of the material, and is suitable for large-scale production.

[0071] From the comparison between Example 1 and Comparative Example 4, it can be seen that the present application improves the capacity and voltage by doping lithium into the sodium battery precursor.

[0072] By comparing Example 1 and Comparative Examples 5-6, it can be seen that the method described in the present application can prepare a sodium battery precursor by controlling the co-precipitation order of the base material and various doping raw materials. The precursor has the characteristics of shared crystallization sites, can stabilize the structure, and improve the cycle performance.

[0073] The applicant declares that the above is only a specific implementation method of the present application, but the protection scope of the present application is not limited thereto. Technical personnel in the relevant technical field should understand that any changes or substitutions that can be easily thought of by technical personnel in the relevant technical field within the technical scope disclosed in this application fall within the protection scope and disclosure scope of this application.

Claims

1. A method for preparing a sodium electrode precursor, comprising the following steps: (1) mixing a nickel salt, a manganese salt and an iron salt with a solvent to obtain a solution A, mixing a copper salt, a complexing agent and a solvent to obtain a solution B, and mixing one or more of a lithium salt, a zinc salt, a titanium salt or a magnesium salt with a solvent to obtain a solution C; (2) injecting alkali solution, ammonia water and solution A into the bottom liquid in parallel to perform a one-step co-precipitation reaction, and injecting ammonia water, alkali solution and solution B into the bottom liquid in parallel to perform a two-step co-precipitation reaction; (3) Injecting the precipitant solution and solution C in parallel to carry out a three-step co-precipitation reaction to obtain the sodium electrode precursor.

2. The preparation method according to claim 1, wherein The nickel salt, manganese salt, iron salt, copper salt, zinc salt, titanium salt or magnesium salt in step (1) includes sulfate, nitrate or chloride.

3. The preparation method according to claim 1 or 2, wherein: The lithium salt includes lithium sulfate.

4. The preparation method according to any one of claims 1 to 3, wherein The complexing agent includes any one of ammonia water, acetic acid, sodium citrate or ethylenediamine, or a combination of at least two of them.

5. The preparation method according to any one of claims 1 to 4, wherein: The mass concentration of the complexing agent in the solution B is 2-5 g / L; Optionally, the total metal molar concentration of the solution A is 1.6 to 2.4 mol / L.

6. The preparation method according to any one of claims 1 to 5, wherein: The base liquid in step (2) comprises ammonia water and alkali solution; Optionally, the pH of the base solution is 9 to 13; Optionally, the ammonia concentration in the base solution is 1 to 10 g / L; Optionally, the temperature of the base liquid is 40-100°C.

7. The preparation method according to any one of claims 1 to 6, wherein: The concentration of the alkali solution in step (2) is 9 to 12 mol / L; Optionally, the concentration of the ammonia water is 7 to 10 mol / L; Optionally, the endpoint of the one-step coprecipitation reaction is that the particle size in the system is a, and a is 3 to 12 μm.

8. The preparation method according to any one of claims 1 to 7, wherein: After the two-step coprecipitation reaction in step (2), the particle size in the system is b, ba = 0.8 to 3 μm.

9. The preparation method according to any one of claims 1 to 8, wherein: The solute of the lithium precipitant solution in step (3) comprises sodium hydroxide and / or potassium hydroxide; Optionally, the concentration of the precipitant solution is 0.8-1.8 mol / L.

10. The preparation method according to any one of claims 1 to 9, wherein: The time of the three-step co-precipitation in step (3) is 3 to 12 hours; Optionally, after the three-step coprecipitation reaction is completed, the particle size of the particles in the system is c, cb = 0.3-0.8 μm.

11. The preparation method according to any one of claims 1 to 10, wherein: Inert gas is introduced during the one-step co-precipitation reaction, the two-step co-precipitation reaction and the three-step co-precipitation reaction.

12. The preparation method according to any one of claims 1 to 11, wherein: The temperature of the one-step coprecipitation reaction, the two-step coprecipitation reaction and the three-step coprecipitation reaction is 40-100° C.; Optionally, the stirring speed of the one-step co-precipitation reaction, the two-step co-precipitation reaction and the three-step co-precipitation reaction is 200-500 rpm.

13. A sodium electrode precursor, wherein: The sodium battery precursor is prepared by the method according to any one of claims 1 to 12, and the chemical formula of the sodium battery precursor is Ni a Fe b Cu c Mn d Li e Zn x Ti y Mg z (OH)2, (a+b+c+d+e+x+y+z=1, and 0.05 <a<0.4,0.05<b<0.4,0.05<c<0.4,0.05<d<0.4,e<0.11,x<0.11,y<0.11,z<0.11)。 14. A positive electrode material, wherein: The positive electrode material is prepared by mixed sintering of the sodium electrode precursor and a sodium source as described in claim 13.

15. A sodium ion battery, wherein: The sodium ion battery comprises the positive electrode material as claimed in claim 14.

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