Sodium-ion battery positive electrode material precursor and preparation method thereof

Abstract

The precursor is one or more of Mn < x > Fe < y > Ni < z > Zn Mg Co < c > O < 2 >, Mn < x > Fe < y > Ni < z > Zn Mg Co < c > CO < 3 > and Mn < x > Fe < y > Ni < z > Zn Mg Co < c > C < 2 > O < 4 >, x is larger than or equal to 0.2 and smaller than 1, y is larger than or equal to 0 and smaller than 0.8, Z is larger than or equal to 0 and smaller than 0.8, a is larger than or equal to 0 and smaller than 0.2, b is smaller than or equal to 0.01, c is larger than or equal to 0 and smaller than 0.2, and x + y + z + a + b + c is equal to 1. The invention further discloses a preparation method of the sodium ion battery positive electrode material precursor, the low-price laterite-nickel ore hydrometallurgy intermediate product cobalt nickel hydroxide (MHP) is used as a raw material, a proper reducing agent solution is selected, and the sodium ion battery positive electrode material precursor with excellent electrochemical performance is directly prepared. And the production cost is reduced, so that the sodium-ion battery has the cost advantage.

Description

Technical Field

[0001] The present invention relates to the field of sodium ion batteries, and in particular to a sodium ion battery positive electrode material precursor and a preparation method thereof, a battery positive electrode material and a battery. Background Art

[0002] As lithium carbonate prices decline, the cost advantage of sodium-ion batteries is gradually diminishing. Nickel-iron-manganese-based sodium-ion battery cathode materials are primarily produced through a co-precipitation reaction of nickel sulfate, manganese sulfate, and ferrous sulfate solutions with a precipitant, followed by sintering with sodium. The more expensive nickel sulfate is primarily purified from laterite nickel ore. The complex purification process and the use of expensive extractants not only result in the loss of metallic elements like nickel and cobalt, but also further increase the raw material cost of nickel sulfate.

[0003] Patent publication number CN103545504A uses fluoride as a precipitant for impurity removal, resulting in fluorine-containing waste residues that are severely environmentally polluting. Patent publication number CN107579218A uses a method for directly preparing a nickel-cobalt-aluminum ternary cathode material precursor from a laterite nickel ore leachate. This method employs a complex multi-step impurity removal process, resulting in the loss of valuable metals. While these patents offer some direction for the high-value utilization of laterite nickel ore, they still pose issues of environmental pollution and loss of valuable metals. Summary of the Invention

[0004] To address the above-mentioned issues, the present invention aims to provide a sodium-ion battery cathode material precursor, a preparation method, a battery cathode material, and a battery. This method utilizes inexpensive laterite nickel ore to hydrometallurgically refine the intermediate nickel cobalt hydroxide (MHP), then uses a suitable reducing agent to fully dissolve the MHP, directly producing a sodium-ion battery cathode material precursor with excellent electrochemical performance. This process eliminates complex impurity removal, shortens the process flow, reduces production costs, and avoids the loss of valuable metal ions. The resulting precursor particles are quasi-spherical secondary particles composed of tightly connected flaky primary particles. Their D50 value is 5 to 18 μm.

[0005] The present invention is achieved through the following technical solutions:

[0006] A sodium ion battery cathode material precursor, Mn x Fe y Ni z Zn a Mg b Co c (OH)2、Mn x Fe y Ni z Zn a Mg b Co c CO3、Mnx Fe y Ni z Zn a Mg b Co c One or more of C2O4, wherein 0.2≤x<1, 0≤y<0.8, 0≤Z<0.8, 0≤a<0.2, b≤0.01, 0≤c<0.2, x+y+z+a+b+c=1.

[0007] The precursor particles are spherical or quasi-spherical, and D50 is 5 to 18 μm.

[0008] A method for preparing a precursor of a positive electrode material for a sodium ion battery, the preparation comprising:

[0009] (1) Dissolution of MHP: Mix MHP with dilute sulfuric acid and add reducing agent solution to fully dissolve MHP. The reducing agent solution is one or more of hydrogen peroxide, sulfurous acid and ascorbic acid. (2) Preparation of mixed salt solution: Prepare mixed salt solution according to the precursor ratio described above. (3) Preparation of reaction base liquid: Mix antioxidant, precipitant solution and complexing agent solution, wherein the precipitant solution is an alkaline solution and the complexing agent solution is one or more of water-soluble chitosan, disodium ethylenediaminetetraacetic acid and ammonia water. (4) Synthesis reaction: In an inert gas atmosphere, the reaction base liquid is first injected into the reaction vessel, and the pH value of the reaction base liquid is adjusted to 7.5-11.5. Then, the mixed salt solution, precipitant solution and complexing agent solution are added to the reaction vessel. The reaction temperature is 30-80°C. After the reaction is completed, the obtained precipitated particles are aged in the reaction vessel. The aging process maintains the reaction conditions during the synthesis unchanged. The selection of the base liquid and the reaction liquid in the present invention allows the prepared precursor particles to be spherical secondary particles composed of tightly connected flaky primary particles.

[0010] The total metal ion concentration in the mixed salt solution is 2 mol / L.

[0011] During the synthesis reaction, the concentration of ammonia water in the reaction environment was maintained at 5 g / L, and the pH of the reaction environment was maintained at 7.5-11.5.

[0012] The precipitant solution is a mixed solution containing one or more of a hydroxide solution, a carbonate solution or an oxalate solution, and the molar concentration thereof is 0.5-10 mol / L.

[0013] The complexing agent solution is 4g / L water-soluble chitosan and 60g / L ammonia solution or the complexing agent solution is 60g / L ammonia solution.

[0014] When implemented, the antioxidant may be sodium sulfite or hydrazine hydrate.

[0015] During implementation, the average mass concentration of the water-soluble chitosan in the complexing agent solution is controlled at 0.01% to 1%.

[0016] During implementation, the average molar concentration of disodium edetate is controlled at 0.0001 to 0.25 mol / L.

[0017] A sodium ion battery positive electrode material, the raw material of which comprises the sodium ion battery positive electrode material precursor as described above.

[0018] A sodium ion battery, the raw materials of which include the sodium ion battery positive electrode material as described above.

[0019] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0020] The low-cost high-entropy sodium-ion battery cathode material precursor and sodium-ion battery cathode material provided in this application limit the content of each element, so that the cathode material prepared from the precursor has good electrochemical performance.

[0021] The present invention utilizes nickel cobalt hydroxide (MHP), an intermediate product of low-cost laterite nickel ore hydrometallurgical smelting, to directly prepare a precursor of a positive electrode material for sodium ion batteries with excellent electrochemical performance. This process eliminates the need for complex impurity removal, shortens the process flow, reduces production costs, and avoids the loss of valuable metal ions. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0023] Figure 1 This is the SEM image of the precursor of Example 1 of the present invention.

[0024] Figure 2 This is the SEM image of the precursor of Comparative Example 1 of the present invention.

[0025] Figure 3 This is the SEM image of the precursor of Comparative Example 2 of the present invention. DETAILED DESCRIPTION

[0026] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with examples and drawings. The exemplary embodiments of the present invention and their descriptions are only used to explain the present invention and are not intended to limit the present invention.

[0027] Example 1

[0028] The chemical formula of the prepared material is Mn 0.4 Fe 0.3 Ni 0.2 Zn 0.08Mg 0.01 Co 0.01 (OH)2, prepared as follows;

[0029] A certain amount of crude nickel cobalt hydroxide (MHP) was weighed and mixed with dilute sulfuric acid, and the pH was adjusted to 1.5-2.5. A certain amount of hydrogen peroxide was added as a reducing agent to reduce the MnO2 in the MHP so that the MHP was completely dissolved. The dissolved solution was mixed with manganese sulfate, ferrous sulfate, zinc sulfate, and magnesium sulfate according to the molar ratio of Mn, Fe, Ni, Zn, Mg, and Co of 40:30:20:8:1:1 to form a mixed salt solution with a total metal ion concentration of 2 mol / L. Sodium hydroxide was weighed as a raw material to prepare a 5 mol / L sodium hydroxide solution as a precipitant solution. 4 g / L water-soluble chitosan and 60 g / L ammonia solution were used as complexing agents.

[0030] Sodium sulfite, complexing agent solution and sodium hydroxide solution were mixed to obtain the reactor bottom liquid, and the bottom liquid pH was adjusted to 10.8; the ammonia concentration was 5 g / L; the sodium sulfite concentration was 0.1 g / L; the stirring paddle was turned on, the speed was adjusted to 800 rpm, the temperature was raised to 40°C, and nitrogen was introduced to maintain the oxygen content of the bottom liquid in the reactor below 0.5%.

[0031] Add mixed salt solution, sodium hydroxide solution, and complexing agent solution to the reactor in parallel. Control the pH of the solution in the reactor to 10.8, the ammonia concentration to 5 g / L, the temperature to 40°C, and the rotation speed to 800 rpm. Stop feeding when the D50 of the precipitated particles reaches 10 μm.

[0032] The obtained particles were aged in a reactor for 10 hours, filtered, washed and dried to obtain manganese iron nickel zinc magnesium cobalt hydroxide. Figure 1 As shown, from Figure 1 It can be seen from the figure that the precursor particles prepared in the present invention are spherical secondary particles composed of tightly connected flaky primary particles.

[0033] Example 2

[0034] The chemical formula of the prepared material is Mn 0.4 Fe 0.3 Ni 0.2 Zn 0.08 Mg 0.01 Co 0.01 CO3, the preparation method is as follows;

[0035] A certain amount of crude nickel cobalt hydroxide (MHP) was weighed and mixed with dilute sulfuric acid, and the pH was adjusted to 1.5-2.5. A certain amount of hydrogen peroxide was added to completely dissolve the MHP. The dissolved solution was then mixed with manganese sulfate, ferrous sulfate, zinc sulfate, and magnesium sulfate at a molar ratio of Mn, Fe, Ni, Zn, Mg, and Co of 40:30:20:8:1:1 to form a mixed salt solution with a total metal ion concentration of 2 mol / L. Sodium carbonate was weighed as a raw material to prepare a 2 mol / L sodium carbonate solution as a precipitant solution. 0.1 mol / L disodium ethylenediaminetetraacetic acid and 60 g / L ammonia solution were used as complexing agents.

[0036] Sodium sulfite, complexing agent solution and sodium carbonate solution were mixed to obtain the reactor bottom liquid, and the bottom liquid pH was adjusted to 7.5; the ammonia concentration was 5 g / L; the sodium sulfite concentration was 0.1 g / L; the stirring paddle was turned on, the speed was adjusted to 800 rpm, the temperature was raised to 40°C, and nitrogen was introduced to maintain the oxygen content of the bottom liquid in the reactor below 0.5%.

[0037] Add mixed salt solution, sodium hydroxide solution, and complexing agent solution to the reactor in parallel. Control the pH of the solution in the reactor to 7.5, the ammonia concentration to 5 g / L, the temperature to 40°C, and the rotation speed to 800 rpm. Stop feeding when the D50 of the precipitated particles reaches 10 μm.

[0038] The obtained particles were aged in a reactor for 10 hours, filtered, washed and dried to obtain a manganese, iron, nickel, zinc, magnesium and cobalt carbonate precipitate.

[0039] Example 3

[0040] The chemical formula of the prepared material is Mn 0.5 Fe 0.25 Ni 0.22 Mg 0.01 Co 0.02 (OH)2, prepared as follows;

[0041] A certain amount of crude nickel cobalt hydroxide (MHP) was weighed and mixed with dilute sulfuric acid, and the pH was adjusted to 1.5-2.5. A certain amount of hydrogen peroxide was added to completely dissolve the MHP. The dissolved solution was then mixed with manganese sulfate and ferrous sulfate in a molar ratio of Mn, Fe, Ni, Mg, and Co of 50:25:22:1:2 to form a mixed salt solution with a total metal ion concentration of 2 mol / L. Sodium hydroxide was weighed as a raw material to prepare a 5 mol / L sodium hydroxide solution as a precipitant solution. 4 g / L water-soluble chitosan and 60 g / L ammonia solution were used as complexing agents.

[0042] Sodium sulfite, complexing agent solution and sodium hydroxide solution were mixed to obtain the reactor bottom liquid, and the bottom liquid pH was adjusted to 10.8; the ammonia concentration was 5 g / L; the sodium sulfite concentration was 0.1 g / L; the stirring paddle was turned on, the speed was adjusted to 800 rpm, the temperature was raised to 40°C, and nitrogen was introduced to maintain the oxygen content of the bottom liquid in the reactor below 0.5%.

[0043] Add the mixed salt solution, sodium oxalate solution, and complexing agent solution to the reactor in parallel. Control the pH of the solution in the reactor to 8, the ammonia concentration to 5 g / L, the temperature to 40°C, and the rotation speed to 800 rpm. Stop feeding when the D50 of the precipitated particles reaches 10 μm.

[0044] The obtained particles were aged in a reactor for 10 hours, filtered, washed and dried to obtain a manganese iron nickel zinc magnesium cobalt oxalate precipitate.

[0045] Comparative Example 1

[0046] Similar to Example 1, except that the reducing agent solution is a 20 g / L ascorbic acid solution.

[0047] Comparative Example 2

[0048] Similar to Example 1, the difference is that the reducing agent solution is a sulfurous acid solution with a mass fraction of 6%.

[0049] Comparative Example 3

[0050] Similar to Example 3, the difference is that the raw materials for preparing the salt solution are all pure sulfate, and MHP is not used.

[0051] The precursors obtained in Example 1, Example 2, Comparative Example 1, Comparative Example 2, Example 3, and Comparative Example 3 were mixed evenly with a sodium source in a mortar and calcined at 900° C. for 10 hours to obtain a sodium ion battery positive electrode material with the chemical formula Na 0.85 Mn 0.4 Fe 0.3 Ni 0.2 Zn 0.1 Mg 0.01 Co 0.01 O2. A button cell was assembled using sodium metal as the negative electrode, polypropylene as the separator, and a solution of NaClO4 in diethylene glycol dimethyl ether as the electrolyte. The electrochemical performance of the assembled cell was tested at 2-4 V and 0.1 C. The results are shown in Table 1.

[0052] Table 1 Performance test data

[0053] project <![CDATA[Initial charging capacity / mAh•g -1 > <![CDATA[Initial discharge capacity / mAh•g -1 > <![CDATA[Discharge specific energy / Wh kg -1 > Example 1 133 128 433 Example 2 132 126 428 Example 3 130 124 424 Comparative Example 1 130 123 432 Comparative Example 2 122 110 398 Comparative Example 3 129 122 421

[0054] A comparison of the electrochemical performance of Example 3 and Comparative Example 3 shows that the cathode material prepared using the more affordable MHP as the raw material for the salt solution exhibits superior electrochemical performance. Example 1, Comparative Example 1, and Comparative Example 2 also reveal significant differences in the morphology of the precursors prepared when reducing MHP with different reducing agents, with the precursor prepared using hydrogen peroxide exhibiting a denser morphology.

[0055] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A sodium ion battery cathode material precursor, characterized in that: Mn x Fe y Ni z Zn a Mg b Co c (OH)2、Mn x Fe y Ni z Zn a Mg b Co c CO3、Mn x Fe y Ni z Zn a Mg b Co c One or more of C2O4, wherein 0.2≤x<1, 0≤y<0.8, 0≤Z<0.8, 0≤a<0.2, b≤0.01, 0≤c<0.2, x+y+z+a+b+c=1.

2. The sodium ion battery cathode material precursor according to claim 1, characterized in that The precursor particles are spherical or quasi-spherical, and D50 is 5 to 18 μm.

3. The method for preparing a sodium ion battery cathode material precursor according to claim 1, characterized in that: The raw materials used are low in cost, and the preparation includes: (1) Dissolution of MHP: Mix MHP with dilute sulfuric acid and add reducing agent solution to fully dissolve MHP. The reducing agent solution is one or more of hydrogen peroxide, sulfurous acid and ascorbic acid. (2) preparing a mixed salt solution: preparing a mixed salt solution according to the precursor ratio described in claim 1; preparing a reaction base solution: mixing an antioxidant, a precipitant solution and a complexing agent solution, wherein the precipitant solution is an alkaline solution, and the complexing agent solution is one or more of water-soluble chitosan, disodium ethylenediaminetetraacetic acid and ammonia water; (3) Synthesis reaction: In an inert gas atmosphere, the reaction base liquid is first injected into the reaction vessel, and the pH value of the reaction base liquid is adjusted to 7.5-11.

5. Then, the mixed salt solution, precipitant solution, and complexing agent solution are added to the reaction vessel. The reaction temperature is 30-80°C. After the reaction is completed, the obtained precipitated particles are aged in the reaction vessel. The aging process maintains the reaction conditions during the synthesis unchanged.

4. The preparation method according to claim 3, characterized in that The total metal ion concentration in the mixed salt solution is 2 mol / L.

5. The preparation method according to claim 3, characterized in that The mass fraction of the reducing agent solution concentration is 2-50%.

6. The preparation method according to claim 3, characterized in that During the synthesis reaction, the concentration of ammonia water in the reaction environment was maintained at 5 g / L, and the pH of the reaction environment was maintained at 7.5-11.

5.

7. The preparation method according to claim 3, characterized in that The precipitant solution is a mixed solution containing one or more of a hydroxide solution, a carbonate solution or an oxalate solution, and the molar concentration thereof is 0.5-10 mol / L.

8. The preparation method according to claim 3, characterized in that The complexing agent solution is 4g / L water-soluble chitosan and 60g / L ammonia solution or the complexing agent solution is 60g / L ammonia solution.

9. A sodium ion battery cathode material, characterized in that The raw materials include the sodium ion battery positive electrode material precursor according to any one of claims 1 and 2.

10. A sodium ion battery, characterized in that: The raw materials include the sodium ion battery positive electrode material according to claim 8.

Images