Sodium ion battery composite electrode material and preparation method thereof

Abstract

The application discloses a kind of sodium ion battery composite electrode materials and preparation method thereof, belong to nanocomposite technical field.The method disclosed in the application, prepared has the sodium ion battery composite electrode material of three-dimensional microsphere structure that ultra-thin two-dimensional nanosheet vertical interweaving constitutes, and the abundant pore between nanosheet is favorable to the quick infiltration of electrolyte, promote active substance and the contact of sodium ion, also be favorable to the sodium ion of disengagement, simultaneously, double metal sulfide doping replaces part of site of ZnO lattice, improve the electron transmission rate of ZnO, and its surface oxidation-reduction reaction rate, buffer the structural damage of electrode material due to volume change of ZnO in charge-discharge process;A layer of carbon nanocage is loaded on the surface of ZnO nanosheet, the size of carbon nanocage is about 100nm, the wall thickness is about 20nm, simultaneously play the role of improving its electron and ion transmission rate, effectively improve the charge-discharge first coulomb efficiency of ZnO negative electrode material.

Description

Technical Field

[0001] This invention belongs to the field of nanocomposite materials technology, specifically relating to a sodium-ion battery composite electrode material and its preparation method. Background Technology

[0002] As a negative electrode material for sodium-ion batteries, zinc oxide (ZnO) exhibits a higher theoretical specific capacity (~978 mAh g⁻¹) compared to other transition metal oxides such as NiO, Co₃O₄, and Fe₃O₄. -1 While ZnO offers advantages such as lower cost and environmental friendliness, its structure changes during charge and discharge, leading to volume expansion. This expansion degrades overall battery performance and can even cause dangerous situations like short circuits. Volume expansion is a major problem for ZnO anodes because it affects battery mechanical stability and cycle life. Furthermore, the ZnO anode material inevitably undergoes redox reactions during charge and discharge, accelerating its aging process. With increasing charge and discharge cycles, the material's fixed structure changes, ultimately reducing its capacity and shortening battery life. Additionally, the inherent low conductivity and severe fragmentation during cycling result in poor rate capability and cycle performance. Generally, designing nanostructures, doping with metal sulfides, and preparing composite materials are effective methods to address these issues. However, while these methods improve the electrochemical activity of ZnO anodes, their cycle stability remains poor, especially the initial coulombic efficiency during charge and discharge. Summary of the Invention

[0003] The purpose of this invention is to provide a sodium-ion battery composite electrode material and its preparation method, in order to solve the technical problem of poor initial coulombic efficiency in existing modified ZnO anode materials.

[0004] To achieve the above objectives, the present invention employs the following technical solution:

[0005] This invention discloses a method for preparing a sodium-ion battery composite electrode material, comprising the following steps:

[0006] After mixing and stirring the zinc salt, complexing agent and solvent to react, the products were collected, washed and dried in sequence to obtain precursor A;

[0007] After mixing and stirring precursor A, dopamine and deionized water to react, the reaction material was collected and calcined to obtain intermediate product B.

[0008] The molybdenum salt, dopamine, and intermediate product B were dispersed in deionized water, and the reaction was carried out by stirring. The solid products were collected sequentially.

[0009] The solid product and sulfur powder were mixed and then calcined to obtain a sodium-ion battery composite electrode material.

[0010] Furthermore, in the step of obtaining precursor A, the ratio of zinc salt, complexing agent and solvent is (1-3)g:(1-3)g:150mL, and the stirring time is 10-20h.

[0011] Furthermore, in the step of obtaining intermediate product B, the ratio of precursor A, dopamine and deionized water is (5-10) g: 1 g: 150 mL, and the stirring time is 10-12 h.

[0012] Furthermore, in the step of obtaining intermediate product B, the calcination treatment is carried out in an inert atmosphere at a temperature of 600–800°C for 1–3 hours.

[0013] Furthermore, in the step of obtaining the solid product, the ratio of the molybdenum salt, dopamine, intermediate product B and deionized water is 1g:1g:(0.1~0.3)g:150mL, and the stirring time is 6~8h.

[0014] Furthermore, before the solid product and sulfur powder are calcined, the solid product is pretreated in a tube furnace at 300-500°C for 2-4 hours; the calcination temperature for the solid product and sulfur powder mixture is 500-600°C, and the time is 2-4 hours.

[0015] Furthermore, the mass ratio of the solid product to sulfur powder is 1:(2-4).

[0016] Further, the zinc salt is one or more of zinc nitrate, zinc sulfate, and zinc chloride; the complexing agent is one or more of 2-ethylimidazole, 4-hydroxymethylimidazole, and 2-chloromethylimidazole; the solvent is anhydrous methanol; and the molybdenum salt is one or two of ammonium molybdate and sodium molybdate.

[0017] The present invention also discloses a sodium-ion battery composite electrode material prepared by the above preparation method.

[0018] Furthermore, the microstructure of the sodium-ion battery composite electrode material consists of bimetallic sulfide-doped zinc oxide nanosheets supported by carbon nanocages; the thickness of the zinc oxide nanosheets is 25-30 nm; the carbon nanocages are 100 nm in size and have a wall thickness of 20 nm.

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

[0020] This invention discloses a method for preparing a sodium-ion battery composite electrode material. Zinc salt, a complexing agent, dopamine, and molybdenum salt are used as raw materials. During the preparation process, a complexing agent is introduced and process parameters are adjusted to prepare an ultrathin two-dimensional nanosheet vertically interwoven to form a three-dimensional microsphere structure. The abundant pores between the nanosheets facilitate rapid electrolyte wetting, promote contact between the active material and sodium ions, and also facilitate sodium ion extraction. Simultaneously, bimetallic sulfide doping replaces some sites in the ZnO lattice, improving the electron transport rate of ZnO and its surface redox reaction rate, thus buffering the structural damage to the electrode material caused by volume changes during charge and discharge. A layer of carbon nanocages, approximately 100 nm in size and 20 nm in wall thickness, is loaded onto the surface of the ZnO nanosheets, further enhancing the electron and ion transport rates and effectively improving the initial coulombic efficiency of the ZnO anode material during charge and discharge. Attached Figure Description

[0021] Figure 1 The images show SEM and TEM images of carbon nanocages in the microstructure of the sodium-ion battery composite electrode material of this invention.

[0022] Wherein: a-SEM image; b-TEM image;

[0023] Figure 2 This is a SEM image of the sodium-ion battery composite electrode material of the present invention;

[0024] Figure 3 The image shows the XRD pattern of the sodium-ion battery composite electrode material of this invention.

[0025] Figure 4 This is a charge-discharge curve of the sodium-ion battery composite electrode material of the present invention. Detailed Implementation

[0026] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0027] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0028] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0029] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0030] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0031] This invention provides a method for preparing a sodium-ion battery composite electrode material, comprising the following steps:

[0032] S1: Dissolve zinc salt (1-3g) and complexing agent (1-3g) in 150mL of anhydrous methanol by ultrasonication, stir at room temperature for 10-20h, collect the product, wash and dry it to prepare precursor A;

[0033] S2: Add precursor A and dopamine to 150 mL of deionized water at a mass ratio of 5-10:1, stir at room temperature for 10-12 h, collect the product, and calcine it under an argon atmosphere to prepare intermediate product B.

[0034] S3: Disperse molybdenum salt, dopamine and intermediate product B in 150 mL of deionized water at a mass ratio of 1:1:0.1-0.3, stir at room temperature for 6-8 h, collect the solid product, wash and dry;

[0035] S4: The above product is first pretreated in a tube furnace, then cooled and sulfur powder is added. After calcination, sodium-ion battery composite electrode material is obtained.

[0036] Preferably, in S1, the zinc salt includes, but is not limited to, zinc nitrate, zinc sulfate, and zinc chloride, and the complexing agent includes, but is not limited to, 2-ethylimidazole, 4-hydroxymethylimidazole, and 2-chloromethylimidazole.

[0037] Preferably, in S2, the calcination temperature is 600–800℃ and the calcination time is 1–3 hours.

[0038] Preferably, in S3, the molybdenum salt includes, but is not limited to, ammonium molybdate and sodium molybdate.

[0039] Preferably, in step S4, the pretreatment temperature is 300–500°C and the pretreatment time is 2–4 hours.

[0040] Preferably, in S4, the mass ratio of solid product to sulfur powder is 1:2 to 4.

[0041] Preferably, in S4, the calcination temperature is 500–600°C and the calcination time is 2–4 hours.

[0042] The present invention also discloses a sodium-ion battery composite electrode material prepared by the above preparation method. The sodium-ion battery composite electrode material is composed of bimetallic sulfide-doped zinc oxide nanosheets loaded with carbon nanocages. The thickness of the nanosheets is 25-30 nm, the size of the carbon nanocages is 100 nm, and the wall thickness is 20 nm.

[0043] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0044] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0045] Example 1

[0046] A method for preparing a sodium-ion battery composite electrode material includes the following steps:

[0047] S1: Dissolve 3g of zinc nitrate (zinc salt) and 3g of 4-hydroxymethylimidazolium (complexing agent) in 150mL of anhydrous methanol by ultrasonication, stir at room temperature for 10h, collect the product, wash and dry it to obtain precursor A;

[0048] S2: Add 10g of precursor A and 1g of predopamine to 150mL of deionized water, stir at room temperature for 12h, collect the product, and calcine it at 800℃ for 3h under argon atmosphere to obtain intermediate product B.

[0049] S3: Disperse 1g ammonium molybdate (molybdenum salt), 1g dopamine and 0.3g intermediate product B in 150mL deionized water, stir at room temperature for 8h, collect the solid product, wash and dry it;

[0050] S4: 1g of solid product was pretreated in a tube furnace at 500℃ for 4h, followed by the addition of 4g of sulfur powder and calcination at 600℃ for 4h to obtain sodium-ion battery composite electrode material.

[0051] Example 2

[0052] A method for preparing a sodium-ion battery composite electrode material includes the following steps:

[0053] S1: Dissolve 1g of zinc chloride (zinc salt) and 2g of 2-chloromethylimidazolium (complexing agent) in 150mL of anhydrous methanol by ultrasonication, stir at room temperature for 15h, collect the product, wash and dry it to obtain precursor A;

[0054] S2: Add 8g of precursor A and 1g of predopamine to 150mL of deionized water, stir at room temperature for 10h, collect the product, and calcine it at 700℃ for 2h under argon atmosphere to obtain intermediate product B.

[0055] S3: Disperse 1g sodium molybdate (molybdenum salt), 1g dopamine and 0.2g intermediate product B in 150mL deionized water, stir at room temperature for 6h, collect the solid product, wash and dry it;

[0056] S4: 1g of solid product was pretreated in a tube furnace at 400℃ for 3h, followed by the addition of 3g of sulfur powder and calcination at 550℃ for 3h to obtain sodium-ion battery composite electrode material.

[0057] Example 3

[0058] A method for preparing a sodium-ion battery composite electrode material includes the following steps:

[0059] S1: Dissolve 1g of zinc sulfate (zinc salt) and 1g of 2-ethylimidazole (complexing agent) in 150mL of anhydrous methanol by ultrasonication, stir at room temperature for 10h, collect the product, wash and dry to obtain precursor A;

[0060] S2: Add 5g of precursor A and 1g of predopamine to 150mL of deionized water, stir at room temperature for 10h, collect the product, and calcine it at 600℃ for 1h under argon atmosphere to obtain intermediate product B.

[0061] S3: Disperse 1g ammonium molybdate (molybdenum salt), 1g dopamine and 0.1g intermediate product B in 150mL deionized water, stir at room temperature for 6h, collect the solid product, wash and dry it;

[0062] S4: 1g of solid product was pretreated in a tube furnace at 300℃ for 2h, followed by the addition of 2g of sulfur powder and calcination at 500℃ for 2h to obtain sodium-ion battery composite electrode material.

[0063] Example 4

[0064] A method for preparing a sodium-ion battery composite electrode material includes the following steps:

[0065] S1: Dissolve 3g of zinc chloride (zinc salt) and 1g of 4-hydroxymethylimidazolium (complexing agent) in 150mL of anhydrous methanol by ultrasonication, stir at room temperature for 15h, collect the product, wash and dry to obtain precursor A;

[0066] S2: Add 8g of precursor A and 1g of predopamine to 150mL of deionized water, stir at room temperature for 10h, collect the product, and calcine it at 650℃ for 2h under argon atmosphere to obtain intermediate product B.

[0067] S3: Disperse 1g sodium molybdate (molybdenum salt), 1g dopamine and 0.3g intermediate product B in 150mL deionized water, stir at room temperature for 8h, collect the solid product, wash and dry it;

[0068] S4: 1g of solid product was pretreated in a tube furnace at 330℃ for 3h, followed by the addition of 4g of sulfur powder and calcination at 500℃ for 3h to obtain sodium-ion battery composite electrode material.

[0069] Example 5

[0070] A method for preparing a sodium-ion battery composite electrode material includes the following steps:

[0071] S1: Dissolve 2g of zinc nitrate (zinc salt) and 3g of 2-chloromethylimidazolium (complexing agent) in 150mL of anhydrous methanol by ultrasonication, stir at room temperature for 18h, collect the product, wash and dry it to obtain precursor A;

[0072] S2: Add 6g of precursor A and 1g of predopamine to 150mL of deionized water, stir at room temperature for 10h, collect the product, and calcine it at 700℃ for 2h under argon atmosphere to obtain intermediate product B.

[0073] S3: Disperse 1g sodium molybdate (molybdenum salt), 1g dopamine and 0.3g intermediate product B in 150mL deionized water, stir at room temperature for 6h, collect the solid product, wash and dry it;

[0074] S4: 1g of solid product was pretreated in a tube furnace at 400℃ for 2h, followed by the addition of 4g of sulfur powder and calcination at 580℃ for 4h to obtain sodium-ion battery composite electrode material.

[0075] Figure 1 The images show SEM and TEM images of the carbon nanocages in the microstructure of the sodium-ion battery composite electrode material of this invention. It can be seen that the carbon nanocages are 100 nm in size and 20 nm in wall thickness.

[0076] Figure 2 and Figure 3 The images shown are SEM and XRD patterns of the sodium-ion battery composite electrode material of the present invention. It can be seen that the microstructure of the sodium-ion battery composite electrode material consists of bimetallic sulfide-doped zinc oxide nanosheets supported by carbon nanocages, and the thickness of the zinc oxide nanosheets is 25-30 nm.

[0077] Figure 4 The charge-discharge curve of the sodium-ion battery composite electrode material of the present invention shows that the composite electrode material prepared by the present invention has an initial discharge specific capacity of 471 mAh / g and an initial coulombic efficiency of 93% at 0.1 A / g, and an initial discharge specific capacity of 361 mAh / g after 100 cycles.

[0078] Table 1 compares the electrochemical performance of the sodium-ion battery composite electrode material prepared in Example 1 of the present invention with that of products obtained in the prior art. As can be seen from the table, the composite electrode material prepared by the present invention has comprehensive electrochemical performance advantages such as specific capacity, initial coulombic efficiency, rate capability, and cycle life.

[0079] Table 1. Comparison of electrochemical performance between the product prepared in this invention and related products.

[0080]

[0081]

[0082] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A method for preparing a sodium-ion battery composite electrode material, characterized in that, Includes the following steps: After mixing and stirring the zinc salt, complexing agent and solvent to react, the products were collected, washed and dried in sequence to obtain precursor A; The complexing agent is one or more selected from 2-ethylimidazole, 4-hydroxymethylimidazole and 2-chloromethylimidazole; the solvent is anhydrous methanol. After mixing and stirring precursor A, dopamine and deionized water to react, the reaction material was collected and calcined to obtain intermediate product B. In the step of obtaining intermediate product B, the ratio of precursor A, dopamine and deionized water is (5~10) g: 1 g: 150 mL, and the stirring time is 10~12 h; The molybdenum salt, dopamine, and intermediate product B were dispersed in deionized water, and the reaction was carried out by stirring. The solid products were collected sequentially. In the step of obtaining the solid product, the ratio of molybdenum salt, dopamine, intermediate product B and deionized water is 1 g: 1 g: (0.1~0.3) g: 150 mL, and the stirring time is 6~8 h; The solid product and sulfur powder were mixed and then calcined to obtain a sodium-ion battery composite electrode material. The microstructure of the sodium-ion battery composite electrode material consists of bimetallic sulfide-doped zinc oxide nanosheets supported by carbon nanocages; the thickness of the zinc oxide nanosheets is 25-30 nm; the carbon nanocages are 100 nm in size and have a wall thickness of 20 nm.

2. The method for preparing a sodium-ion battery composite electrode material according to claim 1, characterized in that, In the step of obtaining precursor A, the ratio of zinc salt, complexing agent and solvent is (1~3) g: (1~3) g: 150 mL, and the stirring time is 10~20 h.

3. The method for preparing a sodium-ion battery composite electrode material according to claim 1, characterized in that, In the step of obtaining intermediate product B, the calcination treatment is carried out in an inert atmosphere at a temperature of 600~800 ℃ for 1~3 h.

4. The method for preparing a sodium-ion battery composite electrode material according to claim 1, characterized in that, Before calcination of the solid product and sulfur powder, the solid product is pretreated in a tube furnace at 300-500 °C for 2-4 h; the calcination of the solid product and sulfur powder is carried out at 500-600 °C for 2-4 h.

5. The method for preparing a sodium-ion battery composite electrode material according to claim 1, characterized in that, The mass ratio of the solid product to sulfur powder is 1:(2~4).

6. The method for preparing a sodium-ion battery composite electrode material according to claim 1, characterized in that, The zinc salt is one or more of zinc nitrate, zinc sulfate, and zinc chloride; the molybdenum salt is one or two of ammonium molybdate and sodium molybdate.

7. A sodium-ion battery composite electrode material, characterized in that, It is prepared by the preparation method described in any one of claims 1 to 6.

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