Process for preparing sodium battery positive electrode material by using high-purity sodium carbonate

Abstract

The invention discloses a process for preparing a sodium battery positive electrode material by using high-purity sodium carbonate, and belongs to the technical field of sodium battery positive electrode materials, and the process comprises the following steps: dissolving a soluble nickel salt, a soluble iron salt and a soluble manganese salt in deionized water to obtain a mixed salt solution, adding an epsilon-polylysine hydrochloride solution, and stirring to obtain a mixed solution; adjusting the pH value of the solution with ammonia water for coprecipitation, and drying the obtained precipitate to obtain a precursor; and dissolving the precursor in deionized water to obtain a precursor solution, adding a sodium carbonate solution, uniformly mixing, freeze-drying to obtain a solid, aging, filtering, washing, drying, and crushing by a ball mill to obtain the positive electrode material. According to the method, the pH value and temperature in the coprecipitation process are accurately controlled, the precursor synthesis condition is optimized, the epsilon-polylysine hydrochloride is coprecipitated with nickel ions, iron ions and manganese ions, so that the positive electrode material precursor with uniform morphology and high crystallinity is obtained, the high purity of the material is ensured, and the preparation process is simple. The structural stability and electrochemical performance of the material are favorably improved.

Description

Technical Field

[0001] The invention belongs to the technical field of sodium battery positive electrode materials, and in particular relates to a process for preparing sodium battery positive electrode materials by using high-purity sodium carbonate. Background Art

[0002] At present, the cost of lithium batteries remains high, and safety performance is difficult to guarantee. Lead-acid batteries have low energy density and are not environmentally friendly. There is an urgent need to develop a low-cost, high-safety, and high-performance battery to meet market demand. Sodium-ion batteries have obvious advantages in resources and safety, and have made breakthroughs in performance and cost. They can well meet market demand. Sodium batteries have ushered in an explosive development stage, and the sodium battery industry chain has been gradually improved. Some companies have already started mass production. 2023 is the first year of the industrialization of sodium batteries. In the future, they will gradually replace lead-acid batteries and low-end lithium batteries. In the field of new energy, sodium batteries have great potential for application in low-speed electric vehicles and energy storage. In the short term, they will be first applied to low-speed electric vehicles and communication backup power storage tracks. The milestone installation from 0 to 1 has been achieved, and it is expected to achieve large-scale volume in the near future. In the medium and long term, they will be used in power batteries and large energy storage. It is expected that the industry will usher in great development in the next 3-5 years. When sodium batteries are fully industrialized, it is expected that there will be a market demand of more than 300 billion per year.

[0003] Sodium battery cathode materials are divided into three categories: transition metal oxides, polyanions, and Prussian blue. Among them, transition metal oxide cathodes are similar in preparation method to lithium battery ternary cathodes and are compatible with equipment. Therefore, lithium battery ternary cathode material manufacturers have entered the market one after another, and many companies have set up shop. It is expected to become the fastest commercialized sodium battery cathode route. The sodium sources of transition metal oxide and polyanion sodium ion batteries include sodium carbonate, sodium hydroxide, sodium bicarbonate, sodium sulfide, etc. According to the prediction of professional organizations, the sodium ion battery industry will have great development in the next 3-5 years, which will inevitably bring about a large-scale growth in the demand for cathode materials, and the market prospects are promising.

[0004] Sodium-ion batteries are currently in a rapid development stage, but they still face many problems and challenges in the process of practical application. Whether from the perspective of energy density, cycle life or actual cost, there is a certain gap with practical needs. Although theoretically, sodium-ion battery electrode materials have a lower operating voltage than the same type of lithium-ion battery electrode materials and have "innate deficiencies" in energy density, the energy density potential of sodium-ion battery electrode materials has not yet been fully realized, and there is still a large gap between the actual energy density and the theoretical upper limit. How to give full play to the application potential of sodium-ion battery electrode materials is still one of the key points and difficulties of sodium-ion battery research. The development of high-performance and low-cost electrode materials is the key to the development of sodium batteries. Summary of the invention

[0005] In view of the above situation, in order to overcome the defects of the prior art, the present invention optimizes the synthesis conditions of the precursor by precisely controlling the pH value and temperature during the coprecipitation process, obtains the precursor by coprecipitation, and then obtains the positive electrode material by sodium carbonate precipitation.

[0006] In order to achieve the above object, the following technical scheme is adopted: The present invention provides a process for preparing a positive electrode material for a sodium battery using high-purity sodium carbonate, comprising the following steps:

[0007] (1) dissolving a soluble nickel salt, a soluble iron salt and a soluble manganese salt in deionized water to obtain a mixed salt solution, adding an ε-polylysine hydrochloride solution, adjusting the pH of the solution to 9.5-11.2 with aqueous ammonia, performing coprecipitation, and drying the obtained precipitate to obtain a precursor;

[0008] (2) The precursor is dissolved in deionized water to obtain a precursor solution, and then a sodium carbonate solution is added, mixed evenly, and freeze-dried to obtain a solid. The precipitate is aged, filtered, washed and dried in sequence, and then crushed in a ball mill to obtain a positive electrode material.

[0009] Furthermore, the soluble nickel salt is one of nickel sulfate, nickel nitrate, nickel chloride or nickel acetate.

[0010] Furthermore, the soluble iron salt is one of ferrous sulfate, ferrous nitrate, ferrous chloride or ferrous acetate.

[0011] Furthermore, the soluble manganese salt is one of manganese sulfate, manganese nitrate, manganese chloride or manganese acetate.

[0012] Furthermore, the molar ratio of metal elements of the soluble nickel salt, the soluble iron salt and the soluble manganese salt is 1:1:1, and the concentration of the mixed salt solution is 1.0-2.0 mol / L.

[0013] Furthermore, the concentration of the ε-polylysine hydrochloride solution is 2.0-5.0 mol / L.

[0014] Furthermore, the coprecipitation temperature is 40-60°C.

[0015] Furthermore, the concentration of the precursor solution is 1.0-3.0 mol / L.

[0016] Furthermore, the concentration of the sodium carbonate solution is 1.0-3.0 mol / L.

[0017] Furthermore, the metal molar ratio of the sodium carbonate solution to the precursor solution is 1:1.

[0018] The beneficial effects of the present invention are:

[0019] (1) The present invention optimizes the synthesis conditions of the precursor by precisely controlling the pH value and temperature during the coprecipitation process, and obtains a positive electrode material precursor with uniform morphology and high crystallinity by coprecipitating ε-polylysine hydrochloride with nickel ions, iron ions and manganese ions. The present invention also uses high-purity sodium carbonate as a sodium source, which not only ensures the high purity of the material, but also helps to improve the structural stability and electrochemical properties of the material. In electrochemical tests, the positive electrode material prepared by the present invention exhibits a higher specific capacity and a longer cycle life, which is of great significance for improving the practicality of sodium batteries;

[0020] (2) The process of the present invention is simple and easy to implement, low in cost, and has a good industrial application prospect. By optimizing the synthesis steps and parameters, the present invention greatly reduces the production cost while maintaining the high performance of the material. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a 0.1C charge-discharge curve diagram of the positive electrode material prepared in Process Example 3 of the present invention for preparing a positive electrode material for a sodium battery using high-purity sodium carbonate.

[0022] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0024] Unless otherwise defined, all professional and scientific terms used herein have the same meanings as those familiar to those skilled in the art. In addition, any methods and materials similar or equivalent to those described herein may be applied to the present invention. The preferred implementation methods and materials described herein are for demonstration purposes only and are not intended to limit the content of this application.

[0025] The experimental methods in the following examples are conventional methods unless otherwise specified, and the experimental materials used in the following examples are purchased from commercial channels unless otherwise specified.

[0026] Example 1

[0027] A process for preparing positive electrode material of sodium battery using high-purity sodium carbonate

[0028] The steps include:

[0029] (1) dissolving a soluble nickel salt, a soluble iron salt and a soluble manganese salt in deionized water to obtain a mixed salt solution, adding an ε-polylysine hydrochloride solution, adjusting the pH of the solution to 9.5 with aqueous ammonia, performing coprecipitation, and drying the obtained precipitate to obtain a precursor;

[0030] (2) The precursor is dissolved in deionized water to obtain a precursor solution, and then a sodium carbonate solution is added, mixed evenly, and freeze-dried to obtain a solid. The precipitate is aged, filtered, washed and dried in sequence, and then crushed in a ball mill to obtain a positive electrode material.

[0031] The soluble nickel salt is nickel sulfate.

[0032] The soluble iron salt is ferrous sulfate.

[0033] The soluble manganese salt is manganese sulfate.

[0034] The molar ratio of metal elements of the soluble nickel salt, the soluble iron salt and the soluble manganese salt is 1:1:1, and the concentration of the mixed salt solution is 1.0 mol / L.

[0035] The concentration of the ε-polylysine hydrochloride solution is 2.0 mol / L.

[0036] The coprecipitation temperature was 40°C.

[0037] The concentration of the precursor solution is 1.0 mol / L.

[0038] The concentration of the sodium carbonate solution is 1.0 mol / L.

[0039] The metal molar ratio of the sodium carbonate solution to the precursor solution is 1:1.

[0040] Example 2

[0041] A process for preparing positive electrode material of sodium battery using high-purity sodium carbonate

[0042] The steps include:

[0043] (1) dissolving a soluble nickel salt, a soluble iron salt and a soluble manganese salt in deionized water to obtain a mixed salt solution, adding an ε-polylysine hydrochloride solution, adjusting the pH of the solution to 11.2 with aqueous ammonia, performing coprecipitation, and drying the obtained precipitate to obtain a precursor;

[0044] (2) The precursor is dissolved in deionized water to obtain a precursor solution, and then a sodium carbonate solution is added, mixed evenly, and freeze-dried to obtain a solid. The precipitate is aged, filtered, washed and dried in sequence, and then crushed in a ball mill to obtain a positive electrode material.

[0045] The soluble nickel salt is nickel nitrate.

[0046] The soluble iron salt is ferrous nitrate.

[0047] The soluble manganese salt is manganese nitrate.

[0048] The molar ratio of metal elements of the soluble nickel salt, the soluble iron salt and the soluble manganese salt is 1:1:1, and the concentration of the mixed salt solution is 2.0 mol / L.

[0049] The concentration of the ε-polylysine hydrochloride solution is 5.0 mol / L.

[0050] The coprecipitation temperature was 60°C.

[0051] The concentration of the precursor solution is 3.0 mol / L.

[0052] The concentration of the sodium carbonate solution is 3.0 mol / L.

[0053] The metal molar ratio of the sodium carbonate solution to the precursor solution is 1:1.

[0054] Example 3

[0055] A process for preparing positive electrode material of sodium battery using high-purity sodium carbonate

[0056] The steps include:

[0057] (1) dissolving a soluble nickel salt, a soluble iron salt and a soluble manganese salt in deionized water to obtain a mixed salt solution, adding an ε-polylysine hydrochloride solution, adjusting the pH of the solution to 10.0 with aqueous ammonia, performing coprecipitation, and drying the obtained precipitate to obtain a precursor;

[0058] (2) The precursor is dissolved in deionized water to obtain a precursor solution, and then a sodium carbonate solution is added, mixed evenly, and freeze-dried to obtain a solid. The precipitate is aged, filtered, washed and dried in sequence, and then crushed in a ball mill to obtain a positive electrode material.

[0059] The soluble nickel salt is nickel chloride.

[0060] The soluble iron salt is ferrous chloride.

[0061] The soluble manganese salt is manganese chloride.

[0062] The molar ratio of metal elements of the soluble nickel salt, the soluble iron salt and the soluble manganese salt is 1:1:1, and the concentration of the mixed salt solution is 1.5 mol / L.

[0063] The concentration of the ε-polylysine hydrochloride solution is 3.0 mol / L.

[0064] The coprecipitation temperature was 50°C.

[0065] The concentration of the precursor solution is 2.0 mol / L.

[0066] The concentration of the sodium carbonate solution is 2.0 mol / L.

[0067] The metal molar ratio of the sodium carbonate solution to the precursor solution is 1:1.

[0068] Results Analysis

[0069] Figure 1 This is a 0.1C charge-discharge curve diagram of the positive electrode material prepared in Example 3. It can be seen from the figure that the first-cycle discharge specific capacity of the positive electrode material prepared in the present invention is significantly improved.

[0070] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

[0071] The present invention and its implementation methods are described above, which is not restrictive. The drawings are only one of the implementation methods of the present invention, and the actual application is not limited thereto. In short, if ordinary technicians in the field are inspired by it and design methods and embodiments similar to the technical solution without creativity without departing from the purpose of the invention, they should all fall within the protection scope of the present invention.

Claims

1. A process for preparing positive electrode materials for sodium batteries using high-purity sodium carbonate, Features: The steps include: (1) dissolving a soluble nickel salt, a soluble iron salt and a soluble manganese salt in deionized water to obtain a mixed salt solution, adding an ε-polylysine hydrochloride solution, adjusting the pH of the solution to 9.5-11.2 with aqueous ammonia, performing coprecipitation, and drying the obtained precipitate to obtain a precursor; (2) dissolving the precursor in deionized water to obtain a precursor solution, adding a sodium carbonate solution, mixing evenly, freeze-drying to obtain a solid, aging, filtering, washing and drying the precipitate in sequence, and then crushing it in a ball mill to obtain a positive electrode material.

2. A process for preparing a positive electrode material for a sodium battery using high-purity sodium carbonate according to claim 1, Features: The soluble nickel salt is one of nickel sulfate, nickel nitrate, nickel chloride or nickel acetate.

3. A process for preparing a positive electrode material for a sodium battery using high-purity sodium carbonate according to claim 2, Features: The soluble iron salt is one of ferrous sulfate, ferrous nitrate, ferrous chloride or ferrous acetate.

4. A process for preparing a positive electrode material for a sodium battery using high-purity sodium carbonate according to claim 3, Features: The soluble manganese salt is one of manganese sulfate, manganese nitrate, manganese chloride or manganese acetate.

5. A process for preparing a positive electrode material for a sodium battery using high-purity sodium carbonate according to claim 4, Features: The molar ratio of metal elements of the soluble nickel salt, the soluble iron salt and the soluble manganese salt is 1:1:1, and the concentration of the mixed salt solution is 1.0-2.0 mol / L.

6. A process for preparing a positive electrode material for a sodium battery using high-purity sodium carbonate according to claim 5, Features: The concentration of the ε-polylysine hydrochloride solution is 2.0-5.0 mol / L.

7. A process for preparing a positive electrode material for a sodium battery using high-purity sodium carbonate according to claim 6, Features: The coprecipitation temperature is 40-60°C.

8. A process for preparing a positive electrode material for a sodium battery using high-purity sodium carbonate according to claim 7, Features: The concentration of the precursor solution is 1.0-3.0 mol / L.

9. A process for preparing a positive electrode material for a sodium battery using high-purity sodium carbonate according to claim 8, Features: The concentration of the sodium carbonate solution is 1.0-3.0 mol / L.

10. A process for preparing a positive electrode material for a sodium battery using high-purity sodium carbonate according to claim 9, Features: The metal molar ratio of the sodium carbonate solution to the precursor solution is 1:1.

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