A preparation method of petal-shaped antimony trioxide

Abstract

The present invention relates to the field of inorganic materials, and specifically to a method for preparing petal-shaped antimony trioxide. The method comprises the following steps: adding an antimony salt to an alcohol solvent, heating the mixture to 40-50°C and stirring the mixture for 30-60 minutes, then adding a morphology control agent and a pH control agent, and finally subjecting the obtained reaction solution to a solvothermal reaction. The precipitate is collected, washed, and dried. The antimony trioxide prepared by the present invention has excellent electrochemical properties, especially good cycle stability. This may be because the special petal-shaped morphology can store more charges and ions, while also providing more transmission channels for the charges and ions, thereby improving the conductivity of the antimony trioxide and slowing down its volume expansion during the charge and discharge process.

Description

Technical Field

[0001] The invention relates to the field of inorganic materials, and in particular to a method for preparing petal-shaped antimony trioxide. Background Art

[0002] In recent years, lithium-ion batteries have become a key component of power systems in mobile devices, electric vehicles, and aerospace applications. Sb2O3, with its high theoretical capacity, low price, abundant reserves, and stable cycling performance, is a promising electrode material. However, Sb2O3 exhibits significant volume expansion during the charge and discharge processes. Repeated insertion and extraction of lithium ions during cycling can lead to material pulverization and agglomeration, severely hindering its practical application. Summary of the Invention

[0003] Purpose of the invention: In order to solve the above technical problems, the present invention proposes a method for preparing petal-shaped antimony trioxide.

[0004] The technical solutions adopted are as follows:

[0005] A preparation method of petal-shaped antimony trioxide:

[0006] Add antimony salt to alcohol solvent, heat to 40-50°C and stir for 30-60 minutes, then add morphology control agent and pH control agent, and finally subject the obtained reaction solution to solvent thermal reaction, collect the precipitate, wash and dry it.

[0007] Furthermore, the antimony salt is any one or more combinations of antimony chloride, antimony sulfate, and antimony nitrate.

[0008] Furthermore, the antimony salt is antimony chloride.

[0009] Furthermore, the alcohol solvent is any one or more combinations of ethanol, ethylene glycol, n-propanol, isopropanol, propylene glycol, and glycerol.

[0010] Furthermore, the morphology control agent includes diethylene glycol ether and polyvinyl pyrrolidone.

[0011] Furthermore, the mass ratio of the diethylene glycol ether to the polyvinyl pyrrolidone is 1-5:1-5.

[0012] Furthermore, the mass ratio of the morphology control agent to the antimony salt is 0.1-1:1.

[0013] Furthermore, the pH control agent is hexamethylenetetramine and / or urea.

[0014] Furthermore, the temperature of the solvothermal reaction is 120-160°C.

[0015] Furthermore, the solvent thermal reaction time is 1-10 hours.

[0016] Beneficial effects of the present invention:

[0017] The present invention provides a method for preparing petal-shaped antimony trioxide. The alcohol solvent is both a solvent and a reactant. The antimony salt reacts with the alcohol solvent to form an antimony alkoxide precursor. At high temperature, the pH control agent slowly decomposes to form OH. - Under the action of the morphology control agent, the antimony alkoxide precursor decomposes and continues to grow to form antimony trioxide particles with a petal-like structure. In the early stage of the decomposition of the antimony alkoxide precursor crystal nucleus, the surface free energy of the generated antimony trioxide grains is high, and it is very easy to agglomerate to form secondary particles. Polyvinyl pyrrolidone can protect them at the moment of nucleation, effectively avoiding secondary growth or agglomeration. The hydroxyl functional groups on diethylene glycol ether are conducive to the formation of Sb 3+ The adsorption and nucleation of ions enables the subsequently generated antimony trioxide to be directionally and stably dispersed and grown on the outer surface of the antimony trioxide grains, ultimately forming a special petal-like morphology. The antimony trioxide prepared by the present invention has excellent electrochemical properties, especially good cycling stability. The reason may be that the special petal-like morphology can store more charges and ions, and can also provide more transmission channels for them, thereby improving the electrical conductivity of the antimony trioxide and slowing down the volume expansion during the charge and discharge process. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is the TEM image of the petal-shaped antimony trioxide prepared in Example 1.

[0019] Figure 2 This is the SEM image of antimony trioxide prepared in Comparative Example 1.

[0020] Figure 3 This is the SEM image of antimony trioxide prepared in Comparative Example 2. DETAILED DESCRIPTION

[0021] Unless otherwise specified, the following examples and comparative examples were conducted in parallel, using the same processing steps and parameters.

[0022] Example 1:

[0023] A preparation method of petal-shaped antimony trioxide:

[0024] 5 g of antimony chloride was added to 300 ml of isopropanol and mixed. The mixture was heated to 45°C and stirred for 60 min. Then 1 g of diethylene glycol ether, 1 g of polyvinyl pyrrolidone and 23 g of hexamethylenetetramine were added and stirred thoroughly to obtain a reaction solution. The reaction solution was sealed in an autoclave and heated to 150°C for 5 h. After cooling naturally to room temperature, the precipitate was collected and washed with deionized water and ethanol in sequence. Finally, it was dried in an oven at 80°C for 10 h. Figure 1 The microscopic morphology is petal-shaped, the size is uniform, and the purity is ≥99.9%.

[0025] Example 2:

[0026] A preparation method of petal-shaped antimony trioxide:

[0027] Add 5g of antimony chloride to 300ml of isopropanol and mix thoroughly. Heat to 45°C and stir for 60 minutes. Then add 0.5g of diethylene glycol ether, 0.5g of polyvinyl pyrrolidone, and 23g of hexamethylenetetramine. Stir thoroughly to obtain a reaction solution. The reaction solution is sealed in an autoclave and heated to 140°C for 8 hours. After cooling naturally to room temperature, the precipitate is collected and washed with deionized water and ethanol in sequence. Finally, it is dried in an oven at 80°C for 10 hours. The microscopic morphology is petal-shaped, the size is uniform, and the purity is ≥99.9%.

[0028] Example 3:

[0029] A preparation method of petal-shaped antimony trioxide:

[0030] 5 g of antimony chloride was added to 300 ml of isopropanol and mixed, and the temperature was raised to 45° C. and stirred for 60 minutes. Then, 1 g of diethylene glycol ether, 0.5 g of polyvinyl pyrrolidone and 23 g of urotropine were added and stirred thoroughly to obtain a reaction solution. The reaction solution was sealed in an autoclave and heated to 160° C. for reaction for 10 hours. After natural cooling and returning to room temperature, the precipitate was collected and washed with deionized water and ethanol in sequence. Finally, it was dried in an oven at 80° C. for 10 hours. The microscopic morphology was petal-shaped, the size was uniform, and the purity was ≥99.9%.

[0031] Comparative Example 1:

[0032] The same as Example 1, except that no diethylene glycol ether was added. Figure 2 The microscopic morphology is irregular agglomerates, and the purity is ≥99.9%.

[0033] Comparative Example 2:

[0034] The same as Example 1, except that polyvinyl pyrrolidone is not added. Figure 3 The microscopic morphology is disc-shaped and the purity is ≥99.9%.

[0035] Performance testing:

[0036] The antimony trioxide prepared in Examples 1-3 of the present invention and Comparative Example 1-2 was used as an active material, N-methyl-2-pyrrolidone was used as a solvent, polyvinylidene fluoride (PVDF) was used as a binder, and acetylene black was used as a conductive agent. The active material, binder, and conductive agent were weighed in a mass ratio of 8:1:1. First, the binder was fully dissolved in the solvent in a weighing bottle, and then the mixture of acetylene black and the active material was slowly added. The slurry obtained by stirring was coated on a clean copper foil using a coating machine. The coated copper foil was placed in a vacuum drying oven and dried at 100°C for 24 hours. It was taken out and punched into a circular negative electrode sample with a diameter of 14 mm using a slicer. The sample was placed in a glove box protected by a high argon atmosphere. The sample was used as a working electrode and the metal lithium sheet was used as the positive electrode sheet. LiPF6 / ethylene carbonated (EC) / dimenthyl Carbonate (DEC) was used as the electrolyte and polypropylene was used as the separator. CR2025 button cells were assembled in the order of negative electrode cap, negative electrode sheet, electrolyte, separator, electrolyte, positive electrode sheet, gasket, and positive electrode cap. The assembled cells were removed from the glove box and the positive and negative electrode shells were pressed and sealed using a sealing machine to obtain CR2025 button cells. The electrochemical performance was tested using a blue electric test system. The cells were activated at a low rate of 0.1C for three cycles and then switched to a charge-discharge cycle test at 1C. The test results are shown in Table 1 below:

[0037] Table 1:

[0038]

[0039] As can be seen from Table 1 above, the antimony trioxide prepared by the present invention has excellent electrochemical properties, especially good cycle stability. The reason may be that the special petal-shaped morphology can store more charges and ions, and can also provide more transmission channels for them, thereby improving the electrical conductivity of antimony trioxide and slowing down the volume expansion during the charge and discharge process.

[0040] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for preparing petal-shaped antimony trioxide, characterized in that: Add antimony salt to alcohol solvent, heat to 40-50°C and stir for 30-60 minutes, then add morphology control agent and pH control agent, and finally perform solvothermal reaction on the obtained reaction solution, collect the precipitate, wash and dry it; The antimony salt is antimony chloride; The alcohol solvent is any one or more combinations of ethanol, ethylene glycol, n-propanol, isopropanol, propylene glycol, and glycerol; The morphology control agent includes diethylene glycol ether and polyvinyl pyrrolidone; The mass ratio of diethylene glycol ether to polyvinyl pyrrolidone is 1-5:1-5; The temperature of the solvothermal reaction is 120-160°C; The solvent thermal reaction time is 1-10h; The mass ratio of the morphology control agent to the antimony salt is 0.1-1:1; The pH control agent is hexamethylenetetramine; The purity of the petal-shaped antimony trioxide is ≥99.9%.

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