A kind of antimony trioxide and its preparation method and application

Abstract

The application relates to the field of inorganic materials, in particular to a kind of antimony trioxide and its preparation method and application, organic antimony precursor is added to O / W / O type double Pickering emulsion, after reaction at 30-50 DEG C, the solid is collected by centrifugation, and after acid washing and water washing, drying can be carried out, the antimony trioxide prepared in the application has a hollow structure, and has a wide application prospect in high-performance energy storage devices such as secondary batteries, and has important economic value.

Description

Technical Field

[0001] This invention relates to the field of inorganic materials, specifically to antimony trioxide, its preparation method, and its applications. Background Technology

[0002] Antimony trioxide (ST) is an important inorganic functional material widely used in flame retardants, catalysts, pigments, glass clarifying agents, and electronic devices due to its unique physicochemical properties, such as high refractive index, high flame retardancy, and good electrochemical activity. In recent years, with the development of nanotechnology, nanostructured ST, especially ST with specific morphologies (such as hollow spheres, nanowires, and nanorods), has attracted widespread attention from the scientific and industrial communities because it exhibits optical, electrical, and chemical properties different from those of bulk materials.

[0003] Among various morphologies, hollow spherical antimony trioxide exhibits great application potential in catalysis and energy storage due to its advantages such as low density, high specific surface area, permeable shell, and confinement effect. For example, in secondary batteries, the hollow structure can effectively buffer the large volume changes generated during lithium / sodium ion insertion and extraction, thereby improving the cycle stability of the electrode material; at the same time, the thinner shell and larger specific surface area are conducive to rapid ion transport, improving rate performance.

[0004] Currently, the main method for preparing hollow spherical antimony trioxide is the template method (hard template and soft template). However, the hard template method involves complex template removal and is prone to structural damage, while soft templates such as micelles or emulsion droplets are easily deformed or broken, resulting in irregular product morphology and easy breakage. This greatly affects the electrochemical performance of the prepared antimony trioxide. Summary of the Invention

[0005] Purpose of the invention: To address the above-mentioned technical problems, this invention proposes an antimony trioxide, its preparation method, and its application.

[0006] The technical solution adopted is as follows: In a first aspect, the present invention provides a method for preparing antimony trioxide: The organic antimony precursor is added to an O / W / O type double Pickering emulsion, reacted at 30-50℃, the solid is collected by centrifugation, and then dried after acid washing and water washing.

[0007] Furthermore, the organic antimony precursor is antimony glycolate. During the reaction, antimony glycolate enters the intermediate aqueous phase under shear force, and the antimony trioxide generated by hydrolysis is deposited between the oil-water interface of the inner and outer layers, eventually forming a microstructure with a hollow spherical structure. Since antimony glycolate is a solid, it needs to be dissolved in ethanol before being added to promote the full reaction.

[0008] The product is soaked and washed with acid to completely remove the calcium carbonate particles used as template agents. The acid used must be able to react with and remove the calcium carbonate without reacting with the antimony trioxide product; a 0.01 mol / L acetic acid solution is preferred. After acid washing, the solid is repeatedly washed with deionized water until neutral to remove residual acid and soluble salts.

[0009] Furthermore, the reaction time is 1-5 hours.

[0010] Furthermore, the O / W / O type dual Pickering emulsion uses hydrophilic calcium carbonate and hydrophobic calcium carbonate as emulsifiers.

[0011] Furthermore, the preparation method of the hydrophilic calcium carbonate is as follows: Calcium carbonate can be surface modified by oxygen plasma.

[0012] Furthermore, the preparation method of the hydrophobic calcium carbonate is as follows: Add calcium carbonate and water to anhydrous ethanol, adjust the pH to 3-5, stir well, add silane coupling agent, disperse by ultrasonic vibration, continue stirring the reaction, collect the solid by centrifugation, wash with anhydrous ethanol and water until neutral, and finally dry.

[0013] First, the alkoxy groups in the silane coupling agent hydrolyze to generate silanol groups. Then, the silanol groups undergo a condensation reaction with the hydroxyl groups on the surface of calcium carbonate, introducing surface-active organic functional groups to the surface of calcium carbonate and completing its surface hydrophobic modification.

[0014] Furthermore, the silane coupling agent is any one or any combination of two or more of KH-550, KH-560, KH-570, and KH-571.

[0015] Furthermore, the preparation method of the O / W / O type dual Pickering emulsion is as follows: Hydrophilic calcium carbonate and a first oil phase are added to an acidic aqueous solution to obtain an O / W type emulsion. Hydrophobic calcium carbonate is dispersed in a second oil phase to obtain an outer oil phase. The first oil phase and the second oil phase are immiscible. Subsequently, the O / W type emulsion is added to the outer oil phase and dispersed to obtain an O / W / O type dual Pickering emulsion.

[0016] Furthermore, the first oil phase and the second oil are immiscible.

[0017] The first oil phase and the second oil phase are different and are respectively selected from vegetable oil, mineral oil, or liquid aliphatic hydrocarbons. Preferably, the first oil phase is paraffin oil and the second oil phase is castor oil.

[0018] Furthermore, the acidic aqueous solution needs to provide an acidic environment with pH < 7 to promote the hydrolysis of antimony glycol, but it cannot react with calcium carbonate and the subsequently generated antimony trioxide. Phenol is the best choice for adjusting the acidity. The acidic aqueous solution is made of phenol and deionized water in a mass ratio of 1:20.

[0019] Secondly, the present invention provides antimony trioxide prepared by the above-described preparation method. The antimony trioxide is characterized by its unique microstructure: a hollow spherical structure.

[0020] Thirdly, this invention provides the application of the aforementioned antimony trioxide in secondary batteries. Specifically, the hollow spherical antimony trioxide can be used as the negative electrode active material in lithium-ion batteries, sodium-ion batteries, or other alkali metal-ion batteries. Its applications include: As a single negative electrode active material, it is mixed with conductive agents (such as acetylene black, Super P) and binders (such as polyvinylidene fluoride, sodium carboxymethyl cellulose, sodium alginate) in a certain mass ratio (e.g. 8:1:1) to form an electrode paste, which is then coated onto a current collector (such as copper foil).

[0021] As an additive to the negative electrode material, it is combined with other active materials (such as graphite, silicon, lithium titanate, etc.) to improve the overall electrochemical performance of the electrode, especially its cycle stability.

[0022] The beneficial effects of this invention are: 1. The core of this invention lies in the creative use of an O / W / O type double Pickering emulsion stabilized by specific calcium carbonate particles as a microreactor, which confines the hydrolysis reaction of the organic antimony precursor to a specific region of the emulsion, thereby guiding the formation of hollow structure particles.

[0023] 2. The stability of Pickering emulsions stems from the irreversible adsorption of solid particles at the oil-water interface, forming a dense mechanical barrier that prevents droplet aggregation and coalescence. This barrier is not significantly affected by the system's pH, ion concentration, temperature, or oil phase composition, and can maintain emulsion homogeneity for a relatively long time. This is beneficial for hydrolysis reactions. In the O / W / O type dual Pickering emulsion of this invention, hydrophobic and hydrophilic calcium carbonate respectively stabilize the inner and outer oil-water interfaces. This Pickering emulsion template method effectively prevents droplet coalescence, resulting in products with uniform particle size and moderate wall thickness, and also exhibiting higher electrochemical performance. Calcium carbonate can be easily and completely removed through an acid washing step, avoiding the cost and environmental problems associated with high-temperature calcination or the use of hazardous chemicals.

[0024] 3. Hollow antimony trioxide structure can significantly shorten the Li... +The hollow structure improves the diffusion path, enhances ion transport efficiency, and thus improves rate performance. Furthermore, it exposes more active sites, increasing the efficiency of Li₂. + The adsorption and reaction sites of the hollow structure can improve the specific capacity. The core challenge of lithium battery anode materials is the volume expansion caused by lithium ion insertion / extraction during charging and discharging. This expansion can lead to particle pulverization, electrode structure damage, and ultimately reduce cycle life. The internal voids of the hollow structure can effectively accommodate this volume change, prevent particle collapse, and improve cycle stability.

[0025] 4. This invention not only provides a method for preparing hollow antimony trioxide, but also has broad application prospects in high-performance energy storage devices such as secondary batteries, and has significant economic value. Attached Figure Description

[0026] Figure 1 This is a TEM image of the antimony trioxide sample prepared in Example 1 of the present invention. Detailed Implementation

[0027] Unless otherwise specified in the examples, the conditions were performed under standard conditions or as recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available products. Techniques not mentioned in this invention refer to existing technologies. Unless otherwise specified, the following examples and comparative examples are parallel experiments, using the same processing steps and parameters.

[0028] Example 1: A method for preparing antimony trioxide: 10g of calcium carbonate with an average particle size of 40nm was placed into the chamber of the NE-OP10 oxygen plasma cleaner, and the chamber was evacuated to a vacuum level of 1×10⁻⁶. -2 Pa, then oxygen is introduced to the working pressure of 30 Pa, the power of the oxygen plasma cleaner is turned on, the discharge power is 50W, the calcium carbonate is treated with oxygen plasma for 240s and then the power is turned off to obtain hydrophilic calcium carbonate.

[0029] 10g of calcium carbonate with an average particle size of 40nm and 100ml of deionized water were added to 300ml of anhydrous ethanol. The pH was adjusted to 4, and the mixture was stirred evenly. Then, 5g of silane coupling agent KH-570 was added dropwise, and the mixture was ultrasonically dispersed for 30min. The reaction was continued for 5h with stirring. After centrifugation, the solid was collected and washed with anhydrous ethanol and water until neutral. Finally, it was dried in an 80℃ vacuum oven for 8h to obtain hydrophobic calcium carbonate.

[0030] Dissolve 5g of phenol in 100ml of deionized water, then add 5g of hydrophilic calcium carbonate and 25g of paraffin oil, and stir at 9000rpm for 10min to obtain an O / W type emulsion. Add 10g of hydrophobic calcium carbonate to 500ml of castor oil and stir evenly to obtain the outer oil phase. Then add the O / W type emulsion to the outer oil phase and stir at 9000rpm for 10min to obtain an O / W / O type double Pickering emulsion.

[0031] 5g of antimony glycolate was dissolved in 10ml of ethanol and added dropwise to an O / W / O type double Pickering emulsion. The mixture was then stirred at 80rpm and 40℃ for 3 hours. After the reaction, the solid was collected by centrifugation, washed successively with 0.01mol / L acetic acid solution and 50℃ deionized water, and then dried to obtain an antimony trioxide sample with a hollow spherical structure. Its TEM image is shown below. Figure 1 It can be seen that the particle size is uniform, the wall thickness is moderate, and there is no damage.

[0032] Example 2: A method for preparing antimony trioxide: 10g of calcium carbonate with an average particle size of 40nm was placed into the chamber of the NE-OP10 oxygen plasma cleaner, and the chamber was evacuated to a vacuum level of 1×10⁻⁶. -2 Pa, then oxygen is introduced to the working pressure of 30 Pa, the power of the oxygen plasma cleaner is turned on, the discharge power is 50W, the calcium carbonate is treated with oxygen plasma for 240s and then the power is turned off to obtain hydrophilic calcium carbonate.

[0033] 10g of calcium carbonate with an average particle size of 40nm and 100ml of deionized water were added to 300ml of anhydrous ethanol. The pH was adjusted to 4, and the mixture was stirred evenly. Then, 5g of silane coupling agent KH-570 was added dropwise, and the mixture was ultrasonically dispersed for 30min. The reaction was continued for 5h with stirring. After centrifugation, the solid was collected and washed with anhydrous ethanol and water until neutral. Finally, it was dried in an 80℃ vacuum oven for 8h to obtain hydrophobic calcium carbonate.

[0034] Dissolve 5g of phenol in 100ml of deionized water, then add 5g of hydrophilic calcium carbonate and 25g of paraffin oil, and stir at 9000rpm for 10min to obtain an O / W type emulsion. Add 10g of hydrophobic calcium carbonate to 500ml of castor oil and stir evenly to obtain the outer oil phase. Then add the O / W type emulsion to the outer oil phase and stir at 9000rpm for 10min to obtain an O / W / O type double Pickering emulsion.

[0035] Dissolve 5g of antimony glycol in 10ml of ethanol and add it dropwise to an O / W / O type double Pickering emulsion. Then stir the mixture at 80rpm and 50℃ for 5h. After the reaction is complete, centrifuge to collect the solid. Wash the solid with 0.01mol / L acetic acid solution and 50℃ deionized water in sequence, and then dry it to obtain an antimony trioxide sample with a hollow spherical structure.

[0036] Example 3: A method for preparing antimony trioxide: 10g of calcium carbonate with an average particle size of 40nm was placed into the chamber of the NE-OP10 oxygen plasma cleaner, and the chamber was evacuated to a vacuum level of 1×10⁻⁶. -2 Pa, then oxygen is introduced to the working pressure of 30 Pa, the power of the oxygen plasma cleaner is turned on, the discharge power is 50W, the calcium carbonate is treated with oxygen plasma for 240s and then the power is turned off to obtain hydrophilic calcium carbonate.

[0037] 10g of calcium carbonate with an average particle size of 40nm and 100ml of deionized water were added to 300ml of anhydrous ethanol. The pH was adjusted to 4, and the mixture was stirred evenly. Then, 5g of silane coupling agent KH-570 was added dropwise, and the mixture was ultrasonically dispersed for 30min. The reaction was continued for 5h with stirring. After centrifugation, the solid was collected and washed with anhydrous ethanol and water until neutral. Finally, it was dried in an 80℃ vacuum oven for 8h to obtain hydrophobic calcium carbonate.

[0038] Dissolve 5g of phenol in 100ml of deionized water, then add 5g of hydrophilic calcium carbonate and 25g of paraffin oil, and stir at 9000rpm for 10min to obtain an O / W type emulsion. Add 10g of hydrophobic calcium carbonate to 500ml of castor oil and stir evenly to obtain the outer oil phase. Then add the O / W type emulsion to the outer oil phase and stir at 9000rpm for 10min to obtain an O / W / O type double Pickering emulsion.

[0039] Dissolve 5g of antimony glycol in 10ml of ethanol and add it dropwise to an O / W / O type double Pickering emulsion. Then stir the mixture at 80rpm and 30℃ for 1h. After the reaction is complete, centrifuge to collect the solid. Wash the solid with 0.01mol / L acetic acid solution and 50℃ deionized water in sequence, and then dry it to obtain an antimony trioxide sample with a hollow spherical structure.

[0040] Example 4: A method for preparing antimony trioxide: 10g of calcium carbonate with an average particle size of 40nm was placed into the chamber of the NE-OP10 oxygen plasma cleaner, and the chamber was evacuated to a vacuum level of 1×10⁻⁶. -2Pa, then oxygen is introduced to the working pressure of 30 Pa, the power of the oxygen plasma cleaner is turned on, the discharge power is 50W, the calcium carbonate is treated with oxygen plasma for 240s and then the power is turned off to obtain hydrophilic calcium carbonate.

[0041] 10g of calcium carbonate with an average particle size of 40nm and 100ml of deionized water were added to 300ml of anhydrous ethanol. The pH was adjusted to 4, and the mixture was stirred evenly. Then, 5g of silane coupling agent KH-570 was added dropwise, and the mixture was ultrasonically dispersed for 30min. The reaction was continued for 5h with stirring. After centrifugation, the solid was collected and washed with anhydrous ethanol and water until neutral. Finally, it was dried in an 80℃ vacuum oven for 8h to obtain hydrophobic calcium carbonate.

[0042] Dissolve 5g of phenol in 100ml of deionized water, then add 5g of hydrophilic calcium carbonate and 25g of paraffin oil, and stir at 9000rpm for 10min to obtain an O / W type emulsion. Add 10g of hydrophobic calcium carbonate to 500ml of castor oil and stir evenly to obtain the outer oil phase. Then add the O / W type emulsion to the outer oil phase and stir at 9000rpm for 10min to obtain an O / W / O type double Pickering emulsion.

[0043] Dissolve 5g of antimony glycol in 10ml of ethanol and add it dropwise to an O / W / O type double Pickering emulsion. Then stir the mixture at 80rpm and 50℃ for 1h. After the reaction is complete, centrifuge to collect the solid, wash it with 0.01mol / L acetic acid solution and 50℃ deionized water in sequence, and then dry it to obtain a sample of antimony trioxide with a hollow spherical structure.

[0044] Example 5: A method for preparing antimony trioxide: 10g of calcium carbonate with an average particle size of 40nm was placed into the chamber of the NE-OP10 oxygen plasma cleaner, and the chamber was evacuated to a vacuum level of 1×10⁻⁶. -2 Pa, then oxygen is introduced to the working pressure of 30 Pa, the power of the oxygen plasma cleaner is turned on, the discharge power is 50W, the calcium carbonate is treated with oxygen plasma for 240s and then the power is turned off to obtain hydrophilic calcium carbonate.

[0045] 10g of calcium carbonate with an average particle size of 40nm and 100ml of deionized water were added to 300ml of anhydrous ethanol. The pH was adjusted to 4, and the mixture was stirred evenly. Then, 5g of silane coupling agent KH-570 was added dropwise, and the mixture was ultrasonically dispersed for 30min. The reaction was continued for 5h with stirring. After centrifugation, the solid was collected and washed with anhydrous ethanol and water until neutral. Finally, it was dried in an 80℃ vacuum oven for 8h to obtain hydrophobic calcium carbonate.

[0046] Dissolve 5g of phenol in 100ml of deionized water, then add 5g of hydrophilic calcium carbonate and 25g of paraffin oil, and stir at 9000rpm for 10min to obtain an O / W type emulsion. Add 10g of hydrophobic calcium carbonate to 500ml of castor oil and stir evenly to obtain the outer oil phase. Then add the O / W type emulsion to the outer oil phase and stir at 9000rpm for 10min to obtain an O / W / O type double Pickering emulsion.

[0047] Dissolve 5g of antimony glycol in 10ml of ethanol and add it dropwise to an O / W / O type double Pickering emulsion. Then stir the mixture at 80rpm and 30℃ for 5h. After the reaction is complete, centrifuge to collect the solid. Wash the solid with 0.01mol / L acetic acid solution and 50℃ deionized water in sequence, and then dry it to obtain a sample of antimony trioxide with a hollow spherical structure.

[0048] Performance testing The samples prepared in Examples 1-5 above, along with commercially available antimony trioxide (AM-Sb2O3-001-1), acetylene black, and polyvinylidene fluoride, were mixed at a mass ratio of 8:1:1. A slurry was prepared using N-methylpyrrolidone as a solvent, coated onto copper foil, dried, and cut into electrode sheets. Using lithium metal sheets as the counter electrode and Celgard 2400 as the separator, 1 mol of lithium hexafluorophosphate was dissolved in 1 L of a mixed organic solvent of diethyl carbonate (DEC), ethylene carbonate (EC), and dimethyl carbonate (DMC) as the electrolyte (V(DEC):V(EC):V(DMC)=1:1:1). CR2032 coin cells were assembled in a glove box, designated as test groups 1-6. The electrochemical performance of the assembled lithium-ion batteries was tested, and the results are shown in Table 1 below. Table 1: As shown in Table 1 above, the antimony trioxide prepared by this invention has excellent electrochemical performance and better cycle stability than commercially available nano antimony trioxide.

[0049] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing antimony trioxide, characterized in that, The organic antimony precursor is added to an O / W / O type double Pickering emulsion, reacted at 30-50℃, the solid is collected by centrifugation, and then dried after acid washing and water washing.

2. The method for preparing antimony trioxide as described in claim 1, characterized in that, The organic antimony precursor is antimony glycol.

3. The method for preparing antimony trioxide as described in claim 1, characterized in that, The O / W / O type dual Pickering emulsion uses hydrophilic calcium carbonate and hydrophobic calcium carbonate as emulsifiers.

4. The method for preparing antimony trioxide as described in claim 3, characterized in that, The preparation method of the hydrophilic calcium carbonate is as follows: Calcium carbonate can be surface modified by oxygen plasma.

5. The method for preparing antimony trioxide as described in claim 3, characterized in that, The preparation method of the hydrophobic calcium carbonate is as follows: Add calcium carbonate and water to anhydrous ethanol, adjust the pH to 3-5, stir well, add silane coupling agent, disperse by ultrasonic vibration, continue stirring the reaction, collect the solid by centrifugation, wash with anhydrous ethanol and water until neutral, and finally dry.

6. The method for preparing antimony trioxide as described in claim 5, characterized in that, The silane coupling agent is any one or any combination of two or more of KH-550, KH-560, KH-570, and KH-571.

7. The method for preparing antimony trioxide as described in claim 6, characterized in that, The preparation method of the O / W / O type dual Pickering emulsion is as follows: Hydrophilic calcium carbonate and a first oil phase are added to an acidic aqueous solution to obtain an O / W type emulsion. Hydrophobic calcium carbonate is dispersed in a second oil phase to obtain an outer oil phase. The first oil phase and the second oil phase are immiscible. Subsequently, the O / W type emulsion is added to the outer oil phase and dispersed to obtain an O / W / O type dual Pickering emulsion.

8. An antimony trioxide, characterized in that, It is prepared by the method of any one of claims 1-7.

9. The antimony trioxide as described in claim 8, characterized in that, The antimony trioxide has a hollow spherical structure.

10. The application of antimony trioxide in secondary batteries as described in claim 8.

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