A spherical porous sodium-ion battery material and its preparation method

Abstract

A spherical porous sodium-ion battery material and its preparation method. The chemical formula of the battery material is Na 0.67 Fe 0.23‑ x Cu x Mn 0.77 O2, where 0

Description

Technical Field

[0001] The present invention relates to the technical field of energy materials, and particularly relates to a spherical porous sodium-ion battery material and a preparation method thereof. Background Art

[0002] As a representative of high-energy density energy storage battery systems, lithium-ion batteries have been widely used in fields such as portable electronic devices and electric vehicles. However, due to the low reserves of lithium, uneven resource distribution, and the increasing price of materials year by year, to a certain extent, it restricts their large-scale application.

[0003] In the periodic table, sodium and lithium are in the same main group and have very similar physical and chemical properties. Sodium-ion batteries have a working principle similar to that of lithium-ion batteries, except that sodium ions are inserted and extracted during the charge and discharge process. Compared with lithium resources, sodium is more abundant in the earth's crust, widely distributed globally, simple to extract, and has a lower cost. Therefore, after large-scale commercialization of sodium-ion batteries, they will have a greater cost advantage. In addition, compared with lithium ions, sodium ions have a lower solvation energy, better interfacial ion diffusion ability; a smaller Stokes diameter, and higher ionic conductivity in the same concentration of electrolyte than lithium ions. At the same time, sodium-ion batteries have better high and low temperature performance. Due to slightly higher internal resistance, the heat generation during short circuit is lower and the safety is higher, making sodium-ion batteries one of the most promising alternatives to lithium-ion batteries. In view of this, promoting the development of sodium-ion batteries and realizing the application of high specific energy sodium-ion batteries has become a key research direction.

[0004] Currently, the research on the positive electrode materials of sodium-ion batteries mainly focuses on crystalline materials, including transition metal layered and tunnel oxides Na x MO2 (M = Mn, Co, Fe, Ni, etc.), polyanion compounds such as Na3V2(PO4)3, Prussian blue compounds such as Na2Fe(CN)6, and some amorphous materials focus on glassy Fe-PO4, V2O5-P2O5 systems. Among them, layered materials have been widely studied due to their stable structure and suitability for insertion and extraction.

[0005] Patent CN105161703A introduces a five-element layered oxide positive electrode material for sodium-ion batteries and a preparation method thereof. It uses sodium carbonate, nickel oxide, cobalt oxide, iron oxide, titanium oxide, and manganese oxide weighed in proportion, mixed and pressed into tablets, and calcined in an oxygen and air atmosphere to obtain a single-phase five-element layered oxide. The problems of this method are: poor controllability and being not conducive to large-scale production.

[0006] Patent CN112456567A introduces a preparation method of a coated structure sodium-ion battery cathode material. A metal salt is dissolved in a volatile solvent to form a suspension, and then a cathode material precursor is added. After mixing evenly, it is dried and calcined to obtain the coated structure sodium-ion battery material. The material prepared by this method has good stability, but the problems are that the volatile solvents used (acetone, N-methylpyrrolidone) are dangerous and have certain harm to the environment, which is not conducive to sustainable development.

[0007] Therefore, developing a preparation method of a sodium-ion battery cathode material with stable and simple process and mild materials is of great significance in this field. Summary of the Invention

[0008] The purpose of the present invention is to provide a spherical porous sodium-ion battery material and a preparation method thereof.

[0009] To achieve the above purpose, the technical solution adopted by the present invention at the material level is:

[0010] A spherical porous sodium-ion battery material, whose chemical formula is Na 0.67 Fe 0.23-x Cu x Mn 0.77 O2, where 0 < x ≤ 0.2; the sodium-ion battery material is spherical porous particles and has a layered structure.

[0011] To achieve the above purpose, the technical solution adopted by the present invention at the method level is:

[0012] A preparation method of a spherical porous sodium-ion battery material, comprising the following steps:

[0013] S1 Precursor Preparation: Weigh MnCl2, FeCl3, and CuCl2 in proportion to prepare a mixed salt solution. Hydrothermally react the mixed salt solution with glycerol, and wash and dry the reaction product to obtain an iron, copper, and manganese carbonate precursor;

[0014] S2 Pre-calcination: Pre-calcine the carbonate precursor obtained in S1 to obtain a ternary iron copper manganese oxide;

[0015] S3 Calcination: Disperse the ternary iron copper manganese oxide obtained in S2 and sodium carbonate in water and mix them. After freeze-drying, calcine them, where the mixing mass ratio of the ternary iron copper manganese oxide to sodium carbonate is 2.5 - 3.5:1 to obtain the sodium-ion battery material.

[0016] Explanation of the relevant content in the above technical solution is as follows:

[0017] 1. In the above solution, in S1, the doping amount of each element in the mixed salt solution is Cu mol / (Fe + Mn + Cu) mol = 0.05 to 0.3.

[0018] 2. In the above solution, in S1, the temperature of the hydrothermal reaction is controlled between 160 °C and 200 °C, and the reaction time is 10 to 20 h.

[0019] 3. In the above solution, in S2, the temperature of the pre - calcination is 350 °C to 500 °C, and the time is 3 to 8 h.

[0020] 4. In the above solution, in S1, the washing is ultrasonic cleaning with deionized water or ethanol; the drying temperature is 60 °C to 80 °C.

[0021] 5. In the above solution, in S3, the temperature of the calcination is 800 °C to 1000 °C.

[0022] 6. In the above solution, the chemical formula of the sodium - ion battery material obtained through S3 is Na 0.67 Fe 0.23- x Cu x Mn 0.77 O2, where 0 < x ≤ 0.2.

[0023] The working principle and advantages of the present invention are as follows:

[0024] 1. The positive electrode material of the sodium - ion battery prepared by the present invention is spherical porous particles with a layered structure, high purity and uniform phase. Through this design, the material is further improved in rate performance and cycle stability, and the working voltage range is also increased to a certain extent;

[0025] 2. The sodium - ion battery material of the present invention uses copper salts to replace cobalt salts and nickel salts, which can effectively reduce the production cost of the material on the premise of meeting high energy density and environmental friendliness;

[0026] 3. The preparation method provided by the present invention has mild reaction conditions, is simple and efficient, has easily available raw materials and is environmentally friendly, and is suitable for large - scale industrial production. Brief Description of the Drawings

[0027] Attached Figure 1 is the XRD pattern of the battery material obtained in Example 1 of the present invention;

[0028] Attached Figure 2 is the SEM image of the battery material obtained in Example 1 of the present invention;

[0029] Attached Figure 3 is the SEM image of the battery material obtained in Example 2 of the present invention;

[0030] Attached Figure 4This is a SEM image of the battery material obtained in Example 3 of the present invention;

[0031] Attached Figure 5 This is a SEM image of the battery material obtained in Example 4 of the present invention. DETAILED DESCRIPTION

[0032] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0033] The present invention will be clearly described below with drawings and detailed descriptions. After understanding the embodiments of the present invention, any person skilled in the art can make changes and modifications based on the techniques taught by the present invention without departing from the spirit and scope of the present invention.

[0034] The terms “include,” “including,” “have,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0035] The terms used in this document generally have the ordinary meaning of each term used in this field, in the context of the case and in the specific context, unless otherwise noted. Certain terms used to describe the present invention will be discussed below or elsewhere in this specification to provide additional guidance to those skilled in the art in describing the present invention.

[0036] Embodiment 1:

[0037] Preparation of S1 precursor: MnCl2·4H2O, FeCl3·6H2O, and CuCl2·2H2O (the molar ratio of Mn, Fe, and Cu is 1:0.24:0.06) are weighed respectively in proportion and dissolved in deionized water to prepare a salt solution, and the salt solution and glycerol (the volume ratio of glycerol to deionized water is 1:2) are hydrothermally reacted at 180°C for 12h, and a carbonate precursor containing iron, copper, and manganese is obtained after washing and drying;

[0038] S2 pre-calcination: pre-calculate the carbonate precursor obtained in S1 at 450°C in air atmosphere for 5 h to obtain ternary iron-copper-manganese oxide;

[0039] S3 calcination: After the oxide obtained in S2 is fully mixed with sodium carbonate in a mass ratio of (n(Mn+Fe+Cu):n(Na)=1:0.66), the temperature is increased to 350°C at a heating rate of 5°C / min and calcined for 2h, and then the temperature is increased to 850°C at the same heating rate of 5°C / min and calcined for 11h to obtain the sodium ion battery material.

[0040] Depend on Figure 1 It can be seen that the chemical formula of the sodium ion battery material prepared in this embodiment is Na 0.67 Fe 0.18 Cu 0.05 Mn 0.77O2 Figure 2 This is the scanning electron microscope image prepared for this example. It can be seen from this figure that the micro-morphology of the prepared battery material is spherical.

[0041] Example 2:

[0042] S1 Precursor Preparation: Weigh MnCl2·4H2O, FeCl3·6H2O, and CuCl2·2H2O in proportion (the molar ratio of Mn, Fe, and Cu is 1:0.18:0.12) and dissolve them in deionized water to prepare a salt solution. Mix the salt solution with glycerol (the volume ratio of glycerol to deionized water is 3:1) and conduct a hydrothermal reaction at 180 °C for 12 h. After washing and drying, a carbonate precursor containing iron, copper, and manganese is obtained.

[0043] S2 Pre-calcination: Pre-calcine the carbonate precursor obtained in S1 at 450 °C for 5 h to obtain a ternary iron-copper-manganese oxide.

[0044] S3 Calcination: Mix the oxide obtained in S2 with sodium carbonate in a mass ratio of (n(Mn + Fe + Cu):n(Na) = 1:0.66). Then, heat it at a heating rate of 5 °C / min to 350 °C and calcine for 2 h. Immediately afterwards, heat it again at the same heating rate of 5 °C / min to 850 °C and calcine for 11 h to obtain the sodium-ion battery material.

[0045] The chemical formula of the sodium-ion battery material prepared in this example is Na 0.67 Fe 0.08 Cu 0.15 Mn 0.77 O2 Figure 3 This is the scanning electron microscope image prepared for this example. It can be seen from this figure that the micro-morphology of the prepared battery material is spherical.

[0046] Example 3:

[0047] S1 Precursor Preparation: Weigh MnCl2·4H2O, FeCl3·6H2O, and CuCl2·2H2O in proportion (the molar ratio of Mn, Fe, and Cu is 1:0.12:0.18) and dissolve them in deionized water to prepare a salt solution. Mix the salt solution with glycerol (the volume ratio of glycerol to deionized water is 3:1) and conduct a hydrothermal reaction at 180 °C for 12 h. After washing and drying, a carbonate precursor containing iron, copper, and manganese is obtained.

[0048] S2 Pre-calcination: Pre-calcine the carbonate precursor obtained in S1 at 400 °C for 6 h to obtain a ternary iron-copper-manganese oxide.

[0049] S3 Calcination: The oxide obtained in S2 and sodium carbonate are fully mixed at a mass ratio of (n(Mn + Fe + Cu):n(Na) = 1:0.66), and then heated to 350°C at a heating rate of 5°C / min for calcination for 2 h. Immediately afterwards, it is heated to 850°C at the same heating rate of 5°C / min and calcined for 11 h to obtain the sodium-ion battery material.

[0050] The chemical formula of the sodium-ion battery material prepared in this example is Na 0.67 Fe 0.08 Cu 0.15 Mn 0.77 O2, Figure 4 This is the scanning electron microscope image prepared in this example. It can be seen from this figure that the microscopic morphology of the prepared battery material is spherical.

[0051] Example 4:

[0052] S1 Preparation of Precursor: Weigh MnCl2·4H2O, FeCl3·6H2O, and CuCl2·2H2O (the molar ratio of Mn, Fe, and Cu is 1:0.06:0.24) respectively according to the ratio and dissolve them in deionized water to prepare a salt solution. The salt solution and glycerol (the volume ratio of glycerol to deionized water is 3:1) are subjected to a hydrothermal reaction at 180°C for 12 h, and a carbonate precursor containing iron, copper, and manganese is obtained after washing and drying;

[0053] S2 Pre-calcination: The carbonate precursor obtained in S1 is pre-calcined at 400°C for 6 h to obtain a ternary iron-copper-manganese oxide;

[0054] S3 Calcination: The oxide obtained in S2 and sodium carbonate are fully mixed at a mass ratio of (n(Mn + Fe + Cu):n(Na) = 1:0.66), and then heated to 350°C at a heating rate of 5°C / min for calcination for 2 h. Immediately afterwards, it is heated to 850°C at the same heating rate of 5°C / min and calcined for 11 h to obtain the sodium-ion battery material.

[0055] The chemical formula of the sodium-ion battery material prepared in this example is Na 0.67 Fe 0.08 Cu 0.15 Mn 0.77 O2, Figure 5 This is the scanning electron microscope image prepared in this example. It can be seen from this figure that the microscopic morphology of the prepared battery material is spherical.

[0056] The above examples are only used to illustrate the technical concept and characteristics of the present invention. The purpose is to enable those familiar with this technology to understand the content of the present invention and implement it accordingly, and it cannot be used to limit the protection scope of the present invention. All equivalent changes or modifications made according to the spirit and essence of the present invention should be covered within the protection scope of the present invention.

Claims

1. A preparation method of a spherical porous sodium-ion battery material, characterized in that: The chemical formula of the spherical porous sodium ion battery material is Na 0.67 Fe 0.23-x Cu x Mn 0.77 O2, where 0.05 ≤ x ≤ 0.15; The sodium-ion battery material is spherical porous particles and has a layered structure; The preparation method of the battery material includes the following steps: S1 Precursor preparation: Weigh MnCl2, FeCl3, and CuCl2 in proportion to prepare a mixed salt solution. Hydrothermally react the mixed salt solution with glycerol, and wash and dry the reaction product to obtain a carbonate precursor containing iron, copper, and manganese; S2 Pre-calcination: Pre-calcine the carbonate precursor obtained in S1 to obtain a ternary iron-copper-manganese oxide; S3 Calcination: Disperse the ternary iron-copper-manganese oxide obtained in S2 and sodium carbonate in water and mix them. After freeze-drying, calcine them, where the mixing mass ratio of the ternary iron-copper-manganese oxide to sodium carbonate is 2.5-3.5:1 to obtain the sodium-ion battery material.

2. The preparation method of the spherical porous sodium ion battery material according to claim 1, wherein: In S1, the temperature of the hydrothermal reaction is controlled between 160 and 200 °C, and the reaction time is 10-20 h.

3. The preparation method of the spherical porous sodium ion battery material according to claim 1, wherein: In S2, the temperature of the pre-calcination is 350-500 °C, and the time is 3-8 h.

4. The preparation method of the spherical porous sodium ion battery material according to claim 1, wherein: In S1, the washing is ultrasonic cleaning with deionized water or ethanol; the drying temperature is 60-80 °C.

5. The preparation method of the spherical porous sodium ion battery material according to claim 1, characterized in that: In S3, the temperature of the calcination is 800-1000 °C.

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