Mesoporous amorphous vanadium oxide-carbon composite electrode material, preparation method and application thereof

Abstract

This invention belongs to the technical field of sodium-ion battery electrode materials, specifically a mesoporous amorphous vanadium oxide-carbon composite electrode material, its preparation method, and its application. The composite electrode material of this invention has a micron-scale mesoporous structure with a specific surface area of ​​50-200 m². 2 g ‑1 The composite electrode material, with mesoporous pores of 10-20 nm, comprises highly amorphous vanadium trioxide and encapsulated carbon. Using a surfactant as a template agent and a carbon source as a coordinating agent, the vanadium source is coordinated in an aqueous solution, followed by drying and calcination to obtain the composite electrode material. This invention is the first to synthesize mesoporous amorphous vanadium trioxide material using a soft template method combined with a reducing carbon source. The preparation process is simple, easy to scale up, and highly controllable. As a sodium-ion battery anode material, it also possesses advantages such as high first-cycle coulombic efficiency, low operating voltage, excellent rate performance, and good cycle stability.

Description

Technical Field

[0001] This invention belongs to the technical field of sodium-ion battery electrode materials, specifically relating to a mesoporous amorphous vanadium oxide-carbon composite electrode material, its preparation method, and its application. Background Technology

[0002] Sodium-ion batteries possess the advantages of abundant resources and low cost, highlighting their enormous natural potential in applications such as large-scale energy storage and smart grids. However, their energy density, power density, and long-term cycle stability remain shortcomings in their practical development and require further improvement. The anode material plays a crucial role in the battery's energy density and stability. The ideal anode material should have a low discharge voltage and a high theoretical capacity. Simultaneously, first-cycle coulombic efficiency, power characteristics, and cycle stability are also important performance indicators.

[0003] Vanadium oxide materials possess diverse valence states, enabling abundant electron transfer and thus playing a crucial role in energy storage. Extensive research on vanadium oxide generally focuses on high-valence vanadium pentoxide and vanadium dioxide, which exhibit high voltage plateaus, making them suitable for cathode materials but not anode materials. Meanwhile, low-valence vanadium oxide materials, such as vanadium trioxide, demonstrate high theoretical capacity and suitable discharge voltage when used as anode materials, showing promising application prospects. However, existing methods for preparing vanadium trioxide materials suffer from drawbacks such as high temperature, high energy consumption, long preparation cycles, uncontrollable material morphology, rapid capacity decay, and poor cycle stability during charge-discharge processes, especially when used as electrode materials in sodium-ion batteries.

[0004] Amorphous nanomaterials possess unique structural features, such as long-range atomic disorder and nanoscale particle or grain size, offering advantageous properties for many material applications. Amorphous materials can provide more active sites for ion intercalation, reduce ion conduction distances, and buffer structural stresses generated during charge and discharge. In electrochemical applications, numerous studies have shown that amorphous materials have certain advantages over crystalline materials. However, due to the serious problems faced by amorphous materials, such as poor intrinsic conductivity, nanostructured electrodes with high conductivity are also crucial for simultaneously achieving high energy storage and rate performance. Given the lack of reports on the successful synthesis and energy storage applications of highly conductive amorphous vanadium trioxide materials, related research is of great significance. Summary of the Invention

[0005] The purpose of this invention is to provide a mesoporous amorphous vanadium oxide-carbon composite electrode material, its preparation method, and its application for assembling sodium-ion batteries.

[0006] The mesoporous amorphous vanadium oxide-carbon composite electrode material provided by this invention has a micron-scale mesoporous structure and a specific surface area of ​​50-200 m².2 g -1 The mesopores have a diameter of 10-20 nm and include highly amorphous vanadium trioxide and encapsulated carbon; the total mass of carbon is 10%-20% of the mass of the composite electrode material.

[0007] Preferably, the mesoporous amorphous vanadium oxide-carbon composite electrode material has a particle size of 2-10 μm.

[0008] The method for preparing the mesoporous amorphous vanadium oxide-carbon composite electrode material provided by this invention uses a surfactant as a template agent and a carbon source with strong reducing and coordinating effects as a ligand. The surfactant and carbon source are dissolved in a solvent, stirred, and then a vanadium source is added to coordinate with it. After stirring and dissolving, the solvent is dried, and the solid is collected to obtain a composite precursor. This precursor is calcined in an inert atmosphere to obtain the mesoporous amorphous vanadium oxide-carbon composite electrode material, comprising highly amorphous vanadium trioxide and encapsulated carbon.

[0009] The molar ratio of the carbon source to the vanadium source is (1-5):(1-5);

[0010] The calcination process involves heating to 600°C at a rate of 5°C / min and holding at that temperature for 3 hours.

[0011] Preferably, the surfactant is one or more of the following: polyethylene oxide-polypropylene oxide, polyethylene oxide-polybutane, polyethylene oxide-polystyrene, polyethylene oxide-polymethyl methacrylate diblock copolymer, polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer, and polypropylene oxide-polyethylene oxide-polypropylene oxide triblock copolymer.

[0012] Preferably, the carbon-based material with strong reducing and coordinating properties is one or more of citric acid, tartaric acid, oxalic acid, malic acid, ascorbic acid, phytic acid, mandelic acid, benzoic acid, salicylic acid, and caffeic acid.

[0013] Preferably, the vanadium source is one or more of the following: ammonium metavanadate, ammonium polyvanadate, sodium metavanadate, sodium pyrovanadate, sodium orthovanadate, vanadium tetrachloride, and vanadium trichloride.

[0014] Preferably, the inert atmosphere is nitrogen or argon.

[0015] An application of the above-mentioned mesoporous amorphous vanadium oxide-carbon composite electrode material is to use the composite electrode material in the preparation of sodium-ion batteries.

[0016] Mesoporous amorphous nanomaterials possess unique structural features, providing more active sites for ion intercalation, reducing ion transport distances, and buffering structural stresses generated during charge and discharge. However, there are currently no reports of successfully synthesizing and applying highly conductive mesoporous amorphous vanadium trioxide (vanadium trioxide) materials for energy storage. Therefore, this invention synthesizes mesoporous amorphous vanadium trioxide materials using a reducing carbon source for application in sodium batteries or sodium-ion batteries, thereby achieving high first-cycle coulombic efficiency, high capacity, excellent rate performance, and cycle stability, which is of great significance. The mesoporous amorphous vanadium trioxide-carbon composite electrode material synthesized in this invention releases more active sites from the porous amorphous vanadium trioxide, effectively shortening the ion transport path and increasing the ion transport rate; simultaneously, the carbon coating structure effectively enhances the conductivity of the amorphous material and alleviates volume expansion, which is beneficial to structural stability. The mesoporous amorphous vanadium trioxide-carbon composite electrode material exhibits high first-cycle coulombic efficiency, high reversible capacity, excellent rate performance, and cycle stability.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] (1) This invention is the first to synthesize a highly amorphous mesoporous vanadium trioxide-carbon composite material using a surfactant template and a carbon source with strong reducing and coordinating properties; the preparation process of this invention is simple, easy to scale up, and highly controllable.

[0019] (2) This invention is the first to realize the synthesis of mesoporous amorphous vanadium oxide-carbon composite electrode material and its application in batteries;

[0020] (3) The mesoporous amorphous vanadium oxide-carbon composite electrode material synthesized in this invention can effectively release more active sites and improve ion transport through the mesoporous structure of the amorphous vanadium trioxide, while the carbon coating structure can effectively improve the conductivity of the amorphous material and at the same time alleviate volume expansion, which is beneficial to structural stability.

[0021] (4) The composite electrode material of the present invention, as the negative electrode material of sodium-ion battery, has the advantages of high first-cycle coulombic efficiency, low operating voltage, excellent rate performance and good cycle stability. The rechargeable sodium-ion battery containing this material has the advantages of high energy density and power density, showing broad market application prospects. Attached Figure Description

[0022] Figure 1 This is the XRD pattern of the mesoporous amorphous vanadium oxide-carbon composite electrode material prepared in Example 1.

[0023] Figure 2 This is an XPS image of the mesoporous amorphous vanadium oxide-carbon composite electrode material prepared in Example 1.

[0024] Figure 3 This is a SEM image of the mesoporous amorphous vanadium oxide-carbon composite electrode material prepared in Example 1.

[0025] Figure 4 This is a TEM image of the mesoporous amorphous vanadium oxide-carbon composite electrode material prepared in Example 1.

[0026] Figure 5 This is an HRTEM image of the mesoporous amorphous vanadium oxide-carbon composite electrode material prepared in Example 1.

[0027] Figure 6 This is a cyclic voltammogram of the mesoporous amorphous vanadium oxide-carbon composite electrode material prepared in Example 1.

[0028] Figure 7 The charge-discharge curves are those of the mesoporous amorphous vanadium oxide-carbon composite electrode material prepared in Example 1.

[0029] Figure 8 This is a rate performance diagram of the mesoporous amorphous vanadium oxide-carbon composite electrode material prepared in Example 1.

[0030] Figure 9 The cycling stability is that of the mesoporous amorphous vanadium oxide-carbon composite electrode material prepared in Example 1.

[0031] Figure 10 This is a TEM image of the amorphous vanadium oxide-carbon composite electrode material prepared in Comparative Example 1.

[0032] Figure 11 This is a charge-discharge curve of the amorphous vanadium oxide-carbon composite electrode material prepared in Comparative Example 1.

[0033] Figure 12 This is a charge-discharge curve of the amorphous vanadium oxide-carbon composite electrode material prepared in Comparative Example 2.

[0034] Figure 13 This is a charge-discharge curve of the amorphous vanadium oxide-carbon composite electrode material prepared in Comparative Example 3.

[0035] Figure 14 This is a TEM image of the vanadium oxide-carbon composite electrode material prepared in Comparative Example 4.

[0036] Figure 15 This is the XRD pattern of the vanadium oxide-carbon composite electrode material prepared in Comparative Example 4.

[0037] Figure 16 This is a charge-discharge curve of the vanadium oxide-carbon composite electrode material prepared in Comparative Example 4.

[0038] Figure 17 This is a TEM image of the vanadium oxide-carbon composite electrode material prepared in Comparative Example 5.

[0039] Figure 18 This is a charge-discharge curve of the vanadium oxide-carbon composite electrode material prepared in Comparative Example 5.

[0040] Figure 19 It is a material synthesized at a calcination temperature of 500℃ with a mesoporous amorphous structure.

[0041] Figure 20 The diagram shows the charge-discharge test conducted within a potential range of 0.01-3.0V. Detailed Implementation

[0042] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The following embodiments are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures; however, the scope of protection of the present invention is not limited to the following embodiments.

[0043] In the following embodiments, unless otherwise specified, the raw materials or processing techniques are conventional commercially available raw materials or conventional processing techniques in the art.

[0044] Example 1

[0045] Add 1.5g of Pluronic F127 (PEO) 106 PPO 70 PEO 106 M w =12600g mol -1 65g (1 / 3 mol) of citric acid was dissolved in 30ml of water to obtain a clear solution. Then, 117g (1 mol) of ammonium metavanadate was added, and the mixture was stirred for 2 hours to dissolve it. After drying and evaporating the solvent at 80℃, the solid was collected to obtain a vanadium oxide-carbon composite precursor. The precursor was ground uniformly and pre-calcined in a tube furnace under an argon atmosphere. Then, it was calcined at 600℃ for 3 hours at a heating rate of 2℃ / min to obtain a mesoporous amorphous vanadium oxide-carbon composite electrode material.

[0046] Figure 1 The X-ray diffraction (XRD) pattern of the mesoporous amorphous vanadium oxide-carbon composite electrode material shows that there are no obvious diffraction peaks, indicating that the material has a completely amorphous structure. At the same time, the broad peak at about 26° is the diffraction peak of the hard carbon (002) crystal plane, and its weak peak intensity also proves its highly amorphous characteristics. Figure 2This is the X-ray photoelectron spectroscopy (XPS) spectrum of the mesoporous amorphous vanadium oxide-carbon composite electrode material obtained in Example 1. It can be seen that vanadium mainly exists in the trivalent valence state, indicating that the amorphous vanadium oxide is vanadium trioxide. Figure 3 The image shows a SEM image of the mesoporous amorphous vanadium oxide-carbon composite electrode material, revealing an overall blocky structure with abundant mesopores. The carbon content is 10% of the mass of the mesoporous amorphous vanadium oxide-carbon composite electrode material. Figure 4 The TEM image shows a mesoporous amorphous vanadium oxide-carbon composite electrode material, revealing abundant and interconnected mesoporous channels with a size of approximately 10-20 nm. Figure 5 The HRTEM images show that the material has obvious highly amorphous properties, and further clarify that the mesopore size is about 10 nm. Figure 6 This is the nitrogen adsorption-desorption isotherm of the mesoporous amorphous vanadium oxide-carbon composite electrode material obtained in Example 1. The adsorption curve is a type I / IV curve, with obvious adsorption corresponding to the mesopores at a relative pressure of 0.7-0.9. The specific surface area of ​​the material is 130 m². 2 g -1 . Figure 7 This is the pore size distribution curve of the mesoporous amorphous vanadium oxide-carbon composite electrode material obtained in Example 1. The curve shows that the material has a uniform pore size of approximately 10 nm.

[0047] The prepared mesoporous amorphous vanadium oxide-carbon composite electrode material was used as the negative electrode active material and mixed with acetylene black and sodium carboxymethyl cellulose at a mass ratio of 80:10:10. Deionized water was used as the dispersant, and the mixture was thoroughly mixed to form a slurry, which was then coated onto copper foil. After vacuum drying at 80℃, a 13mm diameter positive electrode sheet was obtained. A sodium metal sheet (16mm diameter) was used as the counter electrode, and a glass fiber membrane (Whatman GF / D) was used as the separator. 1M NaPF6 dissolved in DGM was used as the electrolyte. A stainless steel shell was used as the outer casing, and the cells were assembled into a CR2025 button cell. The sodium battery assembled in the above process was tested for charge and discharge at room temperature within a potential range of 0.01-3.0V. Its cyclic voltammetry curve is shown below. Figure 8 As shown, the material exhibits fewer irreversible reactions in the first cycle, indicating a relatively high first-cycle coulombic efficiency. Furthermore, the second and third cycles largely overlap, demonstrating a highly reversible redox reaction. The first-cycle charge-discharge curve of this material is shown below. Figure 9 As shown. 0.05A g -1 The reversible specific capacity is approximately 400 mAh g. -1 It has a first-week coulomb efficiency of 90%. Figure 10 The graph shows the rate performance test results at 10A g. -1 It has approximately 170 mAh g at a current density. -1The reversible capacity, while at 30A g -1 It still has about 98mAh g at high current density -1 The reversible capacity demonstrates the material's excellent rate performance. Figure 11 The graph shows the cyclic stability test results for this material at 10 A g. -1 It can cycle stably for 400 cycles at a current density with high capacity retention.

[0048] Comparative Example 1:

[0049] Most of the components are the same as in Example 1, except that F127 is omitted in this example.

[0050] like Figure 12 As shown, without the addition of F127, the synthesized material exhibits abundant mesopores with smaller dimensions, which may be due to the decomposition of ammonia in ammonium vanadate. Charge-discharge tests were performed within a potential range of 0.01-3.0V. Figure 13 As shown, 0.05A g -1 The reversible specific capacity is only 199mAh g. -1 The material exhibits a first-cycle coulombic efficiency of 75%, indicating that without the addition of F127, the synthesized material cannot form a large mesopore size. A mesopore size of around 2 nm is not conducive to electrolyte diffusion and ion transport, and also results in a higher specific surface area, leading to its low capacity and first-cycle coulombic efficiency.

[0051] Comparative Example 2:

[0052] Most of the contents are the same as in Example 1, except that the amount of F127 added is reduced by 0.4g in this example.

[0053] When the amount of F127 added was reduced, the synthesized material was subjected to charge-discharge tests within a potential range of 0.01-3.0V. Figure 14 As shown, at 0.05A g -1 The reversible specific capacity is approximately 306 mAh g. -1 It has a first-cycle coulombic efficiency of 68%, but its first-cycle discharge plateau is lower. This indicates that when the F127 content is low, the synthesized material may have more surface exposure, which will cause more electrolyte decomposition, resulting in a large amount of irreversible capacity in the first cycle, leading to low first-cycle coulombic efficiency and capacity.

[0054] Comparative Example 3:

[0055] Most of the contents are the same as in Example 1, except that in this example, the amount of F127 added is 3.0g.

[0056] When the amount of F127 added was increased, the synthesized material was subjected to charge-discharge tests within a potential range of 0.01-3.0V. Figure 15 As shown, at 0.05A g -1 The reversible specific capacity is approximately 305 mAh g. -1 The material exhibits a first-cycle coulombic efficiency of 85.2%, and its first-cycle discharge curve is similar to that of the sample in Example 1. This indicates that when the F127 content is high, the synthesized material may have less surface exposure. Although this can reduce the decomposition of the electrolyte in the first cycle, due to its larger bulk structure, this may cause irreversible sodium insertion / extraction reactions in the vanadium oxide material, thereby leading to a decrease in its first-cycle coulombic efficiency and capacity.

[0057] Comparative Example 4:

[0058] The majority of the contents are the same as in Example 1, except that the calcination temperature is changed to 700°C in this example.

[0059] like Figure 16 As shown, when the calcination temperature is 700℃, it can be seen that vanadium trioxide in the synthesized material exists in the form of nanoparticles with a size of about 10nm and has a relatively high degree of crystallinity. Figure 17 The XRD pattern further confirms the presence of vanadium trioxide in this material. For example... Figure 18 As shown, charge-discharge tests were performed within a potential range of 0.01-3.0V, with a capacitance of 0.05A g. -1 The charging capacity in the first week is approximately 355mAh g. -1 The charging capacity in the second week was approximately 330mAh g. -1 The loss of some capacity indicates that highly crystalline vanadium trioxide nanoparticles can cause irreversible sodium insertion / extraction reactions, leading to capacity loss during cycling.

[0060] Comparative Example 5:

[0061] Most of the contents are the same as in Example 1, except that the calcination temperature is changed to 500°C in this example.

[0062] like Figure 19 As shown, when the calcination temperature is 500℃, the synthesized material structure is similar to that of Example 1, both being mesoporous amorphous structures. Figure 20 As shown, charge-discharge tests were performed within a potential range of 0.01-3.0V, with a capacitance of 0.05Ag. -1 The charging capacity in the first week is approximately 228mAh g. -1The first-week coulombic efficiency was approximately 59%, and the first-week discharge plateau was low. The second-week coulombic efficiency was also low. This indicates that at the lower calcination temperature, the degree of carbonization of citric acid was lower, resulting in more electrolyte decomposition in the first week to form a solid electrolyte interface film, thus achieving a low first-week coulombic efficiency and capacity.

[0063] Example 2

[0064] Add 1.5g of Pluronic F127 (PEO) 106 PPO 70 PEO 106 M w =12600g mol -1 192 g (1 mol) of citric acid was dissolved in 30 ml of water to obtain a clear solution. Then, 117 g (1 mol) of ammonium metavanadate was added and stirred for 2 hours to dissolve it. After drying and evaporating the solvent at 80 °C, the solid was collected to obtain a vanadium oxide-carbon composite precursor. The precursor was ground uniformly and pre-calcined in a tube furnace under an argon atmosphere. Then, it was calcined at 600 °C for 3 hours at a heating rate of 2 °C / min to obtain a mesoporous amorphous vanadium oxide-carbon composite electrode material.

[0065] The prepared mesoporous amorphous vanadium oxide-carbon composite electrode material was used as the positive electrode active material and mixed with acetylene black and sodium carboxymethyl cellulose at a mass ratio of 80:10:10. Deionized water was used as the dispersant, and the mixture was thoroughly mixed to form a slurry, which was then coated onto copper foil. After vacuum drying at 80℃, a 13mm diameter positive electrode sheet was obtained. A sodium metal sheet (16mm diameter) was used as the negative electrode, and a glass fiber membrane (Whatman GF / D) was used as the separator. 1M NaPF6 dissolved in DGM was used as the electrolyte. A stainless steel shell was used as the outer casing, and the cells were assembled into a CR2025 button cell. Charge-discharge performance tests were performed.

[0066] Example 3

[0067] Add 1.5g of Pluronic F127 (PEO) 106 PPO 70 PEO 106 M w =12600g mol -1 390 g (2 mol) of citric acid was dissolved in 30 ml of water to obtain a clear solution. Then, 117 g (1 mol) of ammonium metavanadate was added and stirred for 2 hours to dissolve it. After drying and evaporating the solvent at 80 °C, the solid was collected to obtain a vanadium oxide-carbon composite precursor. The precursor was ground uniformly and pre-calcined in a tube furnace under an argon atmosphere. Then, it was calcined at 600 °C for 3 hours at a heating rate of 2 °C / min to obtain a mesoporous amorphous vanadium oxide-carbon composite electrode material.

[0068] The prepared mesoporous amorphous vanadium oxide-carbon composite electrode material was used as the positive electrode active material and mixed with acetylene black and sodium carboxymethyl cellulose at a mass ratio of 80:10:10. Deionized water was used as the dispersant, and the mixture was thoroughly mixed to form a slurry, which was then coated onto copper foil. After vacuum drying at 80℃, a 13mm diameter positive electrode sheet was obtained. A sodium metal sheet (16mm diameter) was used as the negative electrode, and a glass fiber membrane (Whatman GF / D) was used as the separator. 1M NaPF6 dissolved in DGM was used as the electrolyte. A stainless steel shell was used as the outer casing, and the cells were assembled into a CR2025 button cell. Charge-discharge performance tests were performed.

[0069] Example 4

[0070] Add 1.5g of Pluronic F127 (PEO) 106 PPO 70 PEO 106 M w =12600g mol -1 65g (1 / 3 mol) of citric acid was dissolved in 30ml of water to obtain a clear solution. Then, 117g (1 mol) of ammonium metavanadate was added and stirred for 2 hours to dissolve it. After drying and evaporating the solvent at 80℃, the solid was collected to obtain a vanadium oxide-carbon composite precursor. The precursor was ground uniformly and pre-calcined in a tube furnace under an argon atmosphere. Then, it was calcined at 550℃ for 3 hours at a heating rate of 2℃ / min to obtain a mesoporous amorphous vanadium oxide-carbon composite electrode material.

[0071] The prepared mesoporous amorphous vanadium oxide-carbon composite electrode material was used as the positive electrode active material and mixed with acetylene black and sodium carboxymethyl cellulose at a mass ratio of 80:10:10. Deionized water was used as the dispersant, and the mixture was thoroughly mixed to form a slurry, which was then coated onto copper foil. After vacuum drying at 80℃, a 13mm diameter positive electrode sheet was obtained. A sodium metal sheet (16mm diameter) was used as the negative electrode, and a glass fiber membrane (Whatman GF / D) was used as the separator. 1M NaPF6 dissolved in DGM was used as the electrolyte. A stainless steel shell was used as the outer casing, and the cells were assembled into a CR2025 button cell. Charge-discharge performance tests were performed.

[0072] Example 5

[0073] Add 1.5g of Pluronic F127 (PEO) 106 PPO 70 PEO 106 M w =12600g mol -165g (1 / 3 mol) of citric acid was dissolved in 30ml of water to obtain a clear solution. Then, 117g (1 mol) of ammonium metavanadate was added and stirred for 2 hours to dissolve it. After drying and evaporating the solvent at 80℃, the solid was collected to obtain a vanadium oxide-carbon composite precursor. The precursor was ground uniformly and pre-calcined in a tube furnace under an argon atmosphere. Then, it was calcined at 650℃ for 3 hours at a heating rate of 2℃ / min to obtain a mesoporous amorphous vanadium oxide-carbon composite electrode material.

[0074] The prepared mesoporous amorphous vanadium oxide-carbon composite electrode material was used as the positive electrode active material and mixed with acetylene black and sodium carboxymethyl cellulose at a mass ratio of 80:10:10. Deionized water was used as the dispersant, and the mixture was thoroughly mixed to form a slurry, which was then coated onto copper foil. After vacuum drying at 80℃, a 13mm diameter positive electrode sheet was obtained. A sodium metal sheet (16mm diameter) was used as the negative electrode, and a glass fiber membrane (Whatman GF / D) was used as the separator. 1M NaPF6 dissolved in DGM was used as the electrolyte. A stainless steel shell was used as the outer casing, and the cells were assembled into a CR2025 button cell. Charge-discharge performance tests were performed.

[0075] Example 6

[0076] Add 1.5g of Pluronic F127 (PEO) 106 PPO 70 PEO 106 M w =12600g mol -1 50 g (1 / 3 mol) of tartaric acid was dissolved in 30 ml of water to obtain a clear solution. Then, 117 g (1 mol) of ammonium metavanadate was added, and the mixture was stirred for 2 hours to dissolve it. After drying and evaporating the solvent at 80 °C, the solid was collected to obtain a vanadium oxide-carbon composite precursor. The precursor was ground uniformly and pre-calcined in a tube furnace under an argon atmosphere. Then, it was calcined at 600 °C for 3 hours at a heating rate of 2 °C / min to obtain a mesoporous amorphous vanadium oxide-carbon composite electrode material.

[0077] The prepared mesoporous amorphous vanadium oxide-carbon composite electrode material was used as the positive electrode active material and mixed with acetylene black and sodium carboxymethyl cellulose at a mass ratio of 80:10:10. Deionized water was used as the dispersant, and the mixture was thoroughly mixed to form a slurry, which was then coated onto copper foil. After vacuum drying at 80℃, a 13mm diameter positive electrode sheet was obtained. A sodium metal sheet (16mm diameter) was used as the negative electrode, and a glass fiber membrane (Whatman GF / D) was used as the separator. 1M NaPF6 dissolved in DGM was used as the electrolyte. A stainless steel shell was used as the outer casing, and the cells were assembled into a CR2025 button cell. Charge-discharge performance tests were performed.

[0078] Example 7

[0079] Add 1.5g of Pluronic F127 (PEO) 106 PPO 70 PEO 106 M w =12600g mol -1 44.7 g (1 / 3 mol) of malic acid was dissolved in 30 ml of water to obtain a clear solution. Then, 117 g (1 mol) of ammonium metavanadate was added, and the solution was stirred for 2 hours to dissolve it. After drying and evaporating the solvent at 80 °C, the solid was collected to obtain a vanadium oxide-carbon composite precursor. The precursor was ground uniformly and pre-calcined in a tube furnace under an argon atmosphere. Then, it was calcined at 600 °C for 3 hours at a heating rate of 2 °C / min to obtain a mesoporous amorphous vanadium oxide-carbon composite electrode material.

[0080] The prepared mesoporous amorphous vanadium oxide-carbon composite electrode material was used as the positive electrode active material and mixed with acetylene black and sodium carboxymethyl cellulose at a mass ratio of 80:10:10. Deionized water was used as the dispersant, and the mixture was thoroughly mixed to form a slurry, which was then coated onto copper foil. After vacuum drying at 80℃, a 13mm diameter positive electrode sheet was obtained. A sodium metal sheet (16mm diameter) was used as the negative electrode, and a glass fiber membrane (Whatman GF / D) was used as the separator. 1M NaPF6 dissolved in DGM was used as the electrolyte. A stainless steel shell was used as the outer casing, and the cells were assembled into a CR2025 button cell. Charge-discharge performance tests were performed.

[0081] Example 8

[0082] Add 1.5g of Pluronic F127 (PEO) 106 PPO 70 PEO 106 M w =12600g mol -1 58.7 g (1 / 3 mol) of ascorbic acid was dissolved in 30 ml of water to obtain a clear solution. Then, 117 g (1 mol) of ammonium metavanadate was added and stirred for 2 hours to dissolve it. After drying and evaporating the solvent at 80 °C, the solid was collected to obtain a vanadium oxide-carbon composite precursor. The precursor was ground uniformly and pre-calcined in a tube furnace under an argon atmosphere. Then, it was calcined at 600 °C for 3 hours at a heating rate of 2 °C / min to obtain a mesoporous amorphous vanadium oxide-carbon composite electrode material.

[0083] The prepared mesoporous amorphous vanadium oxide-carbon composite electrode material was used as the positive electrode active material and mixed with acetylene black and sodium carboxymethyl cellulose at a mass ratio of 80:10:10. Deionized water was used as the dispersant, and the mixture was thoroughly mixed to form a slurry, which was then coated onto copper foil. After vacuum drying at 80℃, a 13mm diameter positive electrode sheet was obtained. A sodium metal sheet (16mm diameter) was used as the negative electrode, and a glass fiber membrane (Whatman GF / D) was used as the separator. 1M NaPF6 dissolved in DGM was used as the electrolyte. A stainless steel shell was used as the outer casing, and the cells were assembled into a CR2025 button cell. Charge-discharge performance tests were performed.

[0084] Example 9

[0085] Add 1.5g of Pluronic F127 (PEO) 106 PPO 70 PEO 106 M w =12600g mol -1 220 g (1 / 3 mol) of phytic acid was dissolved in 30 ml of water to obtain a clear solution. Then, 117 g (1 mol) of ammonium metavanadate was added, and the mixture was stirred for 2 hours to dissolve it. After drying and evaporating the solvent at 80 °C, the solid was collected to obtain a vanadium oxide-carbon composite precursor. The precursor was ground uniformly and pre-calcined in a tube furnace under an argon atmosphere. Then, it was calcined at 600 °C for 3 hours at a heating rate of 2 °C / min to obtain a mesoporous amorphous vanadium oxide-carbon composite electrode material.

[0086] The prepared mesoporous amorphous vanadium oxide-carbon composite electrode material was used as the positive electrode active material and mixed with acetylene black and sodium carboxymethyl cellulose at a mass ratio of 80:10:10. Deionized water was used as the dispersant, and the mixture was thoroughly mixed to form a slurry, which was then coated onto copper foil. After vacuum drying at 80℃, a 13mm diameter positive electrode sheet was obtained. A sodium metal sheet (16mm diameter) was used as the negative electrode, and a glass fiber membrane (Whatman GF / D) was used as the separator. 1M NaPF6 dissolved in DGM was used as the electrolyte. A stainless steel shell was used as the outer casing, and the cells were assembled into a CR2025 button cell. Charge-discharge performance tests were performed.

[0087] Example 10

[0088] Add 1.5g of Pluronic F127 (PEO) 106 PPO 70 PEO 106 M w =12600g mol -146 g (1 / 3 mol) of salicylic acid was dissolved in 30 ml of water to obtain a clear solution. Then, 117 g (1 mol) of ammonium metavanadate was added and stirred for 2 hours to dissolve it. After drying and evaporating the solvent at 80 °C, the solid was collected to obtain a vanadium oxide-carbon composite precursor. The precursor was ground uniformly and pre-calcined in a tube furnace under an argon atmosphere. Then, it was calcined at 600 °C for 3 hours at a heating rate of 2 °C / min to obtain a mesoporous amorphous vanadium oxide-carbon composite electrode material.

[0089] The prepared mesoporous amorphous vanadium oxide-carbon composite electrode material was used as the positive electrode active material and mixed with acetylene black and sodium carboxymethyl cellulose at a mass ratio of 80:10:10. Deionized water was used as the dispersant, and the mixture was thoroughly mixed to form a slurry, which was then coated onto copper foil. After vacuum drying at 80℃, a 13mm diameter positive electrode sheet was obtained. A sodium metal sheet (16mm diameter) was used as the negative electrode, and a glass fiber membrane (Whatman GF / D) was used as the separator. 1M NaPF6 dissolved in DGM was used as the electrolyte. A stainless steel shell was used as the outer casing, and the cells were assembled into a CR2025 button cell. Charge-discharge performance tests were performed.

[0090] Example 11

[0091] Add 1.5g of Pluronic F127 (PEO) 106 PPO 70 PEO 106 M w =12600g mol -1 65g (1 / 3 mol) of citric acid was dissolved in 30ml of water to obtain a clear solution. Then, 299g (1 mol) of ammonium polyvanadate was added and stirred for 2 hours to dissolve it. After drying and evaporating the solvent at 80℃, the solid was collected to obtain a vanadium oxide-carbon composite precursor. The precursor was ground uniformly and pre-calcined in a tube furnace under an argon atmosphere. Then, it was calcined at 600℃ for 3 hours at a heating rate of 2℃ / min to obtain a mesoporous amorphous vanadium oxide-carbon composite electrode material.

[0092] The prepared mesoporous amorphous vanadium oxide-carbon composite electrode material was used as the positive electrode active material and mixed with acetylene black and sodium carboxymethyl cellulose at a mass ratio of 80:10:10. Deionized water was used as the dispersant, and the mixture was thoroughly mixed to form a slurry, which was then coated onto copper foil. After vacuum drying at 80℃, a 13mm diameter positive electrode sheet was obtained. A sodium metal sheet (16mm diameter) was used as the negative electrode, and a glass fiber membrane (Whatman GF / D) was used as the separator. 1M NaPF6 dissolved in DGM was used as the electrolyte. A stainless steel shell was used as the outer casing, and the cells were assembled into a CR2025 button cell. Charge-discharge performance tests were performed.

[0093] Example 12

[0094] Add 1.5g of Pluronic F127 (PEO) 106 PPO 70 PEO 106 M w =12600g mol -1 65g (1 / 3 mol) of citric acid was dissolved in 30ml of water to obtain a clear solution. Then, 122g (1 mol) of sodium metavanadate was added, and the mixture was stirred for 2 hours to dissolve it. After drying and evaporating the solvent at 80℃, the solid was collected to obtain a vanadium oxide-carbon composite precursor. The precursor was ground uniformly and pre-calcined in a tube furnace under an argon atmosphere. Then, it was calcined at 600℃ for 3 hours at a heating rate of 2℃ / min to obtain a mesoporous amorphous vanadium oxide-carbon composite electrode material.

[0095] The prepared mesoporous amorphous vanadium oxide-carbon composite electrode material was used as the positive electrode active material and mixed with acetylene black and sodium carboxymethyl cellulose at a mass ratio of 80:10:10. Deionized water was used as the dispersant, and the mixture was thoroughly mixed to form a slurry, which was then coated onto copper foil. After vacuum drying at 80℃, a 13mm diameter positive electrode sheet was obtained. A sodium metal sheet (16mm diameter) was used as the negative electrode, and a glass fiber membrane (Whatman GF / D) was used as the separator. 1M NaPF6 dissolved in DGM was used as the electrolyte. A stainless steel shell was used as the outer casing, and the cells were assembled into a CR2025 button cell. Charge-discharge performance tests were performed.

[0096] Example 13

[0097] Add 1.5g of Pluronic F127 (PEO) 106 PPO 70 PEO 106 M w =12600g mol -1 65g (1 / 3 mol) of citric acid was dissolved in 30ml of water to obtain a clear solution. Then, 117g (1 mol) of ammonium metavanadate was added, and the mixture was stirred for 2 hours to dissolve it. After drying and evaporating the solvent at 80℃, the solid was collected to obtain a vanadium oxide-carbon composite precursor. The precursor was ground uniformly and pre-calcined in a tube furnace under an argon atmosphere. Then, it was calcined at 600℃ for 3 hours at a heating rate of 2℃ / min to obtain a mesoporous amorphous vanadium oxide-carbon composite electrode material.

[0098] The prepared mesoporous amorphous vanadium oxide-carbon composite electrode material was used as the positive electrode active material and mixed with acetylene black and sodium carboxymethyl cellulose at a mass ratio of 80:10:10. Deionized water was used as the dispersant, and the mixture was thoroughly mixed to form a slurry, which was then coated onto copper foil. After vacuum drying at 80℃, a 13mm diameter positive electrode sheet was obtained. A sodium metal sheet (16mm diameter) was used as the negative electrode, and a glass fiber membrane (Whatman GF / D) was used as the separator. 1M NaSO3CF3 dissolved in DGM was used as the electrolyte. A stainless steel shell was used as the outer casing, and the cells were assembled into a CR2025 button cell. Charge-discharge performance tests were performed.

[0099] Example 14

[0100] Add 1.5g of Pluronic F127 (PEO) 106 PPO 70 PEO 106 M w =12600g mol -1 65g (1 / 3 mol) of citric acid was dissolved in 30ml of water to obtain a clear solution. Then, 117g (1 mol) of ammonium metavanadate was added, and the mixture was stirred for 2 hours to dissolve it. After drying and evaporating the solvent at 80℃, the solid was collected to obtain a vanadium oxide-carbon composite precursor. The precursor was ground uniformly and pre-calcined in a tube furnace under an argon atmosphere. Then, it was calcined at 600℃ for 3 hours at a heating rate of 2℃ / min to obtain a mesoporous amorphous vanadium oxide-carbon composite electrode material.

[0101] The prepared mesoporous amorphous vanadium oxide-carbon composite electrode material was used as the positive electrode active material and mixed with acetylene black and sodium carboxymethyl cellulose at a mass ratio of 80:10:10. Deionized water was used as the dispersant, and the mixture was thoroughly mixed to form a slurry, which was then coated onto copper foil. After vacuum drying at 80℃, a 13mm diameter positive electrode sheet was obtained. A sodium metal sheet (16mm diameter) was used as the negative electrode, and a glass fiber membrane (Whatman GF / D) was used as the separator. 1M NaClO4 dissolved in EC / DEC was used as the electrolyte. A stainless steel shell was used as the outer casing, and the cells were assembled into a CR2025 button cell. Charge-discharge performance tests were performed.

[0102] Example 15

[0103] Add 1.5g of Pluronic F127 (PEO) 106 PPO 70 PEO 106 M w =12600g mol -165g (1 / 3 mol) of citric acid was dissolved in 30ml of water to obtain a clear solution. Then, 117g (1 mol) of ammonium metavanadate was added, and the mixture was stirred for 2 hours to dissolve it. After drying and evaporating the solvent at 80℃, the solid was collected to obtain a vanadium oxide-carbon composite precursor. The precursor was ground uniformly and pre-calcined in a tube furnace under an argon atmosphere. Then, it was calcined at 600℃ for 3 hours at a heating rate of 2℃ / min to obtain a mesoporous amorphous vanadium oxide-carbon composite electrode material.

[0104] The prepared mesoporous amorphous vanadium oxide-carbon composite electrode material was used as the positive electrode active material and mixed with acetylene black and sodium carboxymethyl cellulose at a mass ratio of 80:10:10. Deionized water was used as the dispersant, and the mixture was thoroughly mixed to form a slurry, which was then coated onto copper foil. After vacuum drying at 80℃, a 13mm diameter positive electrode sheet was obtained. A sodium metal sheet (16mm diameter) was used as the negative electrode, and a glass fiber membrane (Whatman GF / D) was used as the separator. 1M NaClO4 dissolved in EC / PC 5% FEC was used as the electrolyte. A stainless steel shell was used as the outer casing, and the cells were assembled into a CR2025 button cell. Charge-discharge performance tests were performed.

[0105] Example 16

[0106] Add 1.5g of Pluronic F127 (PEO) 106 PPO 70 PEO 106 M w =12600g mol -1 65g (1 / 3 mol) of citric acid was dissolved in 30ml of water to obtain a clear solution. Then, 117g (1 mol) of ammonium metavanadate was added, and the mixture was stirred for 2 hours to dissolve it. After drying and evaporating the solvent at 80℃, the solid was collected to obtain a vanadium oxide-carbon composite precursor. The precursor was ground uniformly and pre-calcined in a tube furnace under an argon atmosphere. Then, it was calcined at 600℃ for 3 hours at a heating rate of 2℃ / min to obtain a mesoporous amorphous vanadium oxide-carbon composite electrode material.

[0107] The prepared mesoporous amorphous vanadium oxide-carbon composite electrode material was used as the negative electrode active material, mixed with acetylene black and sodium carboxymethyl cellulose at a mass ratio of 80:10:10, and deionized water was used as the dispersant. The mixture was thoroughly mixed and formulated into a slurry, which was then coated onto copper foil. Commercially available sodium vanadium phosphate was used as the positive electrode active material, mixed with acetylene black and polyvinylidene fluoride at a mass ratio of 70:20:10, and 1-methyl-2-pyrrolidone was used as the dispersant. The mixture was thoroughly mixed and formulated into a slurry, which was then coated onto aluminum foil. After vacuum drying at 80℃, negative and positive electrode sheets with a diameter of 13 mm were obtained. A glass fiber membrane (Whatman GF / D) was used as the separator, and 1M NaPF6 dissolved in DGM was used as the electrolyte. A stainless steel shell was used as the outer casing, and the cells were assembled into a CR2025 button cell. The assembled sodium-ion battery was charged and discharged at room temperature within a potential range of 1.5-3.6V. Charge and discharge performance tests were performed.

[0108] Example 17

[0109] Add 1.5g of Pluronic F127 (PEO) 106 PPO 70 PEO 106 M w =12600g mol -1 65g (1 / 3 mol) of citric acid was dissolved in 30ml of water to obtain a clear solution. Then, 117g (1 mol) of ammonium metavanadate was added, and the mixture was stirred for 2 hours to dissolve it. After drying and evaporating the solvent at 80℃, the solid was collected to obtain a vanadium oxide-carbon composite precursor. The precursor was ground uniformly and pre-calcined in a tube furnace under an argon atmosphere. Then, it was calcined at 600℃ for 3 hours at a heating rate of 2℃ / min to obtain a mesoporous amorphous vanadium oxide-carbon composite electrode material.

[0110] The prepared mesoporous amorphous vanadium oxide-carbon composite electrode material was used as the negative electrode active material, mixed with acetylene black and sodium carboxymethyl cellulose at a mass ratio of 80:10:10, and deionized water was used as the dispersant. The mixture was thoroughly mixed and formulated into a slurry, which was then coated onto copper foil. Commercially available sodium vanadium phosphate was used as the positive electrode active material, mixed with acetylene black and polyvinylidene fluoride at a mass ratio of 70:20:10, and 1-methyl-2-pyrrolidone was used as the dispersant. The mixture was thoroughly mixed and formulated into a slurry, which was then coated onto aluminum foil. After vacuum drying at 80℃, negative and positive electrode sheets with a diameter of 13 mm were cut. A glass fiber membrane (Whatman GF / D) was used as the separator, and 1M NaClO4 dissolved in EC / DEC was used as the electrolyte. A stainless steel shell was used as the outer casing, and the cells were assembled into a CR2025 button cell. The assembled sodium-ion battery was charged and discharged at room temperature within a potential range of 1.5-3.6V. Charge and discharge performance tests were performed.

[0111] The sodium-ion batteries assembled using the composite electrode materials prepared in Examples 2-17 as electrode active materials exhibited similar charge-discharge performance to those in Example 1, both showing excellent performance; details omitted.

[0112] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A mesoporous amorphous vanadium oxide-carbon composite electrode material, characterized in that, microporous structure, specific surface area of 50-200 m 2 g -1 , mesoporous pore size of 10-20 nm, particle size of 2-10 μm; including highly amorphous vanadium trioxide and wrapped carbon; the total mass of carbon is 10%-20% of the mass of the composite electrode material; prepared by the following method: Using a surfactant as a template agent and a carbon source with strong reducing and coordinating properties as a ligand, the surfactant and carbon source were dissolved in a solvent, and after stirring, a vanadium source was added to coordinate with it. After stirring to dissolve, the solvent was dried, and the solid was collected to obtain a composite precursor. The precursor was calcined in an inert atmosphere to obtain a mesoporous amorphous vanadium oxide-carbon composite electrode material, wherein: The molar ratio of the carbon source to the vanadium source is (1-5):(1-5). The calcination was carried out by heating to 600 °C at a heating rate of 5 °C / min and holding at that temperature for 3 h. The surfactant is one or more of the following: polyethylene oxide-polypropylene oxide, polyethylene oxide-polybutane, polyethylene oxide-polystyrene, polyethylene oxide-polymethyl methacrylate diblock copolymer, polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer, and polyethylene oxide-polypropylene oxide-polypropylene oxide triblock copolymer. The carbon source is one or more of the following: citric acid, tartaric acid, oxalic acid, malic acid, ascorbic acid, phytic acid, mandelic acid, benzoic acid, salicylic acid, and caffeic acid.

2. The mesoporous amorphous vanadium oxide-carbon composite electrode material according to claim 1, characterized in that, The vanadium source is one or more of ammonium metavanadate, ammonium polyvanadate, sodium metavanadate, sodium pyrovanadate, sodium orthovanadate, vanadium tetrachloride, and vanadium trichloride.

3. The mesoporous amorphous vanadium oxide-carbon composite electrode material according to claim 1, characterized in that, The inert atmosphere is nitrogen or argon.

4. The application of the mesoporous amorphous vanadium oxide-carbon composite electrode material as described in any one of claims 1-3 in the preparation of sodium-ion batteries, specifically using the composite electrode material as the negative electrode of the sodium-ion battery.

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