Preparation method of antimony sulfide with good crystallinity and application of antimony sulfide in sodium-ion battery

Abstract

The invention belongs to the technical field of nano materials, and particularly relates to a preparation method of antimony sulfide with good crystallinity and application of the antimony sulfide in a sodium ion battery. Antimony oxide is used as an antimony source, sulfide salt is used for dissolving the antimony source, antimony sulfide precipitates are obtained by adjusting the pH value of the solution, and the method specifically comprises the following steps that S1, the sulfide salt and antimony oxide are evenly mixed and then stirred at a high speed in water to be dissolved, a dispersing agent is added, and an antimony solution is obtained; s2, controlling the temperature of the antimony solution, adding an acid solution, adjusting the pH value, and stirring for reaction to obtain a precipitate; s3, filtering out the precipitate obtained in S2, washing with absolute ethyl alcohol for three times, and then drying at low temperature to obtain antimony sulfide particles; and calcining the antimony sulfide particles under the protection of inert gas to obtain the nano antimony sulfide with good crystallinity. The method has the advantages that the prepared nano antimony sulfide is uniform in granularity, good in dispersity and controllable in morphology; the product has the advantages of few impurities, high yield and high yield; the technological process is simple and low in cost.

Description

Technical Field

[0001] The present invention belongs to the technical field of nanomaterials, and particularly relates to a preparation method of antimony sulfide with good crystallinity and its application in sodium-ion batteries. Background Art

[0002] Sb 2 S 3 is a typical transition metal sulfide, belonging to the orthorhombic semiconductor material, which is an important semiconductor material with a wide range of applications. In Patent CN107089681A and Patent CN116903035A, the antimony sulfide used for preparing photocatalysts is disclosed; Patent CN109504939B and Patent CN116497315A disclose the preparation of antimony sulfide thin films for the field of solar cells.

[0003] In recent years, due to the depletion of fossil fuels and the complex diversity of the ecological environment, the development of sustainable and low-cost clean energy has been a hot issue in recent research. Sodium-ion batteries (SIBs) have received great attention as ideal alternatives for sustainable energy systems due to their low cost and high performance.

[0004] As a new type of secondary battery with great research value and application prospects, the anode material is one of the bottlenecks restricting its commercialization. Based on the dual sodium storage mechanisms of reversible conversion and alloying, antimony-based sulfur compounds have extremely high theoretical specific capacities and are very promising anode materials in sodium-ion batteries; however, during the charge and discharge process, due to problems such as severe volume expansion and low conductivity, the cycle stability and rate performance are poor, which seriously hinders their development and application. Constructing nanostructured nanoscale antimony-based sulfides is an effective strategy to solve the above defects. Summary of the Invention

[0005] To solve the problems existing in the prior art, the present invention provides a preparation method of antimony sulfide with good crystallinity and its application in sodium-ion batteries. Using antimony oxide as a raw material, it is dissolved in a sulfide salt solution to obtain an antimony solution, and then the pH of the antimony solution is adjusted with an acid solution at low temperature. Under the dispersion and structure-directing effects of a dispersant, antimony sulfide precipitates out. The obtained antimony sulfide has a crystalline and ordered nanostructure, and the antimony sulfide precipitate can be calcined at low temperature and high pressure to obtain nanoscale antimony sulfide with good crystallinity.

[0006] To solve the above technical problems, the present invention adopts the following technical solutions: One of the purposes of the present invention is to provide a preparation method of antimony sulfide with good crystallinity, and the preparation method includes the following steps: S1. Dissolution of Sulfur Salt Mix the sulfide salt and antimony oxide in proportion and place them in a dissolution tank. Then add pure water and stir at high speed to completely dissolve them. After adjusting the antimony concentration, add a dispersant and mix evenly to obtain an antimony solution.

[0007] S2. Adjust the acidity Control the temperature of the antimony solution at 0 - 30 °C. Slowly add the acid solution while stirring, control the end point pH, and continue stirring and reacting for 1 - 6 h to obtain a precipitate.

[0008] S3. Filter and calcine Filter out the precipitate obtained in S2, wash it three times with absolute ethanol, and then perform low-temperature drying to obtain antimony sulfide particles; calcine the antimony sulfide particles under the protection of an inert gas to obtain nano-antimony sulfide with good crystallinity.

[0009] Preferably, the sulfide salt in S1 is one of sodium sulfide, potassium sulfide, or ammonium sulfide, and the mass ratio of the sulfide salt to antimony oxide is 2 - 8:1.

[0010] The sulfide salt is both a dissolving agent for antimony oxide and a precipitating agent for antimony sulfide. If the amount of sulfide salt is too small, the dissolution efficiency of antimony oxide is slow and the antimony precipitation is incomplete. If the amount of sulfide salt is too large, hydrogen sulfide is easily generated and volatilized during the acid-adjusted precipitation process, causing environmental pollution and waste of sulfide salt. Therefore, the mass ratio of the sulfide salt to antimony oxide is preferably 2 - 8:1, and more preferably 3 - 6:1.

[0011] Preferably, the antimony concentration in S1 is 50 - 300 g / L; too low antimony concentration will reduce production efficiency and increase the amount of wastewater at the same time, while too high concentration is likely to cause the precipitation powder to grow coarser, which is not conducive to powder refinement. More preferably, the antimony concentration is 100 - 250 g / L.

[0012] Preferably, the high-speed stirring rate in S1 is 1200 - 1500 rpm, and the stirring time is 20 - 30 min.

[0013] Preferably, the dispersant in S1 is one or more of ethylene glycol, PVP, and CTAB, and the addition amount is 1 - 10% of the mass of the antimony solution.

[0014] Preferably, the acid in the acid solution in S2 is one or more of hydrochloric acid, acetic acid, oxalic acid, and citric acid.

[0015] Preferably, the mass fraction of the acid solution in S2 is 20 - 70%, and the addition rate is 2 - 10 ml / min; the addition speed will directly affect the addition amount of the acid and indirectly affect the precipitation reaction rate. Too low addition speed will lead to a decrease in precipitation efficiency, and too fast addition speed will cause the particles to grow faster and become coarser. Therefore, the addition rate is preferably 2 - 10 ml / min, and more preferably 4 - 8 ml / min.

[0016] Preferably, the final pH in S2 is 1 - 9, more preferably 2 - 7.

[0017] Preferably, the stirring rate in S2 is 400 - 1200 rpm, and the stirring reaction time is 1 - 6 h.

[0018] The temperature of the antimony solution affects the growth of the generated crystals. If the temperature is too high, the particle growth rate will be too fast. Therefore, the temperature of the antimony solution is preferably 0 - 30°C, more preferably 0 - 20°C; stirring is beneficial to the homogenization of the solution and the refinement of the particles. By controlling the stirring rate and the stirring reaction time, if the stirring reaction time is too short, the reaction is incomplete and the precipitation rate is reduced. If the stirring reaction time is too long, the formed particles are likely to become coarser. Therefore, the stirring rate is controlled at 400 - 1200 rpm, and the stirring reaction time is controlled at 1 - 6 h. More preferably, the stirring rate is 600 - 1000 rpm, and the stirring reaction time is 2 - 4 h.

[0019] Preferably, the calcination pressure in S3 is 0.5 - 2 MPa, more preferably 0.8 - 1.5 MPa.

[0020] Preferably, the calcination temperature in S3 is 150 - 400°C, and the calcination time is 1 - 5 h; if the calcination temperature is too low, the crystal form conversion is incomplete. If the calcination temperature is too high, it is easy to cause the powder to sinter and become coarser. The calcination time affects the crystal form conversion rate of the powder. Therefore, the calcination temperature is 150 - 400°C, and the calcination time is 1 - 5 h. More preferably, the calcination temperature is 200 - 350°C, and the calcination time is 2 - 4 h.

[0021] Preferably, the temperature of the low-temperature drying in S3 is 40 - 60°C, and the time is 18 - 24 h.

[0022] Preferably, the inert gas is one of nitrogen or argon.

[0023] The dissolution of the sulfide salt and the acidity adjustment are for synthesizing antimony sulfide precipitate. This step is mainly to obtain antimony sulfide particles with uniform particle size and finer particles. The purpose of calcination is to make the crystal grain size of the particles better.

[0024] The reaction equations of S1 - S3 are as follows: The melting reaction of the sulfur salt dissolution: The sulfide salt and antimony oxide react to form thioantimonate.

[0025] Sb 2 O 3 +6S 2- +3H 2 O=2SbS 3 3- +6OH - Neutralization precipitation reaction for adjusting acidity: Thioantimonate reacts with acid to form amorphous antimony sulfide.

[0026] 2SbS 3 3- +6H + =Sb 2 S 3 ↓+3H 2 S↑ H + +OH - =H 2 O H 2 S+OH - =HS - +H 2 O (3)Calcination reaction of filtration and calcination: Amorphous antimony sulfide is transformed into crystalline antimony sulfide.

[0027] Sb 2 S 3 (Amorphous)=Sb 2 S 3 (Crystalline) The second object of the present invention is to provide an application of antimony sulfide with good crystallinity in sodium-ion batteries, and the application is that the nano-antimony sulfide prepared by S1-S3 can be used as the negative electrode active material of sodium-ion batteries.

[0028] Due to the adoption of the above technical solutions, the technical effects achieved by the present invention are: 1. Antimony oxide is easily soluble in sulfide salts and has a large solubility, so the production of antimony sulfide is easier to control, the production efficiency is high, the output of nano-antimony sulfide is higher, and the output is above 95%.

[0029] 2. Antimony sulfide precipitates at low temperature, reducing the grain growth rate, and the obtained antimony sulfide particles are finer and the particle size is more uniform.

[0030] 3. The crystal form transformation of antimony sulfide is realized by calcination. Under high pressure, the crystal form transformation is faster, and at the same time, the transformation temperature is reduced, reducing energy consumption.

[0031] 4. A dispersant is added to the antimony solution, which plays a dispersing role and a structure guiding role, so that the generated antimony sulfide grows along the crystal plane direction and has better dispersibility. Description of the drawings

[0032] Figure 1 is the flow chart of S1-S3 of the present invention; Figure 2 is the XRD result of the uncalcined antimony sulfide particles in Examples 1, 2, and 3 of the present invention; Figure 3XRD results of nano-antimony sulfide after calcination in Examples 1 and 3 of the present invention; Figure 4 、 5 SEM image of nano-antimony sulfide in Example 2 of the present invention; Figure 6 The number of cycles of the nano-antimony sulfide prepared in Examples 1-3 as the negative electrode active material of a sodium-ion battery. Detailed implementation manners

[0033] The present invention will be further described below in conjunction with specific embodiments.

[0034] Example 1: A method for preparing antimony sulfide with good crystallinity, the preparation method comprising the following steps: S1. Dissolution of sulfur salt 40 g of sodium sulfide and 10 g of antimony oxide are mixed evenly and placed in a dissolution tank, then pure water is added, and it is stirred at a high speed to completely dissolve it. After adjusting the antimony concentration to 50 g / L, an ethylene glycol dispersant is added, and after mixing evenly, an antimony solution is obtained.

[0035] The rate of the high-speed stirring is 1300 rpm, and the stirring time is 25 min.

[0036] The addition amount of the ethylene glycol dispersant accounts for 7% of the mass of the antimony solution.

[0037] S2. Adjustment of acidity The antimony solution is placed in a constant temperature water bath, the temperature of the antimony solution is controlled at 10 °C, the stirring rate is adjusted to 1000 rpm, and while stirring, a peristaltic pump is started to slowly add a hydrochloric acid solution with a mass fraction of 40% at a rate of 6 ml / min. The end point pH is controlled at 1, and stirring and reacting are continued for 2 h to obtain a precipitate.

[0038] S3. Filtration and calcination The precipitate obtained in S2 is filtered out, washed three times with absolute ethanol, and then dried at a low temperature. The low-temperature drying temperature is 50 °C and the time is 20 h to obtain antimony sulfide particles; the antimony sulfide particles are placed in a tube furnace, and under the protection of nitrogen, the high-purity nitrogen gas in the tube is completely emptied to keep the tube pressure at 2 MPa, and calcined at 150 °C for 2 h to obtain powdery nano-antimony sulfide with good crystallinity, with a weight of 11.33 g and a yield of 97.34%.

[0039] Example 2: A method for preparing antimony sulfide with good crystallinity, the preparation method comprising the following steps: S1. Dissolution of sulfur salt 60 g of sodium sulfide and 10 g of antimony oxide are mixed evenly and placed in a dissolution tank, then pure water is added, and it is stirred at a high speed to completely dissolve it. After adjusting the antimony concentration to 150 g / L, a PVP dispersant is added, and after mixing evenly, an antimony solution is obtained.

[0040] The rate of the high-speed stirring is 1200 rpm, and the stirring time is 30 min.

[0041] The addition amount of the PVP dispersant accounts for 3% of the mass of the antimony solution.

[0042] S2. Adjust the acidity Place the antimony solution in a constant-temperature water bath, control the temperature of the antimony solution at 20 °C, adjust the stirring rate to 600 rpm, and while stirring, turn on the peristaltic pump to slowly add a hydrochloric acid solution with a mass fraction of 20% at an addition rate of 10 ml / min. Control the final pH to be 5, and continue stirring and reacting for 4 h to obtain a precipitate.

[0043] S3. Filter and calcine Filter out the precipitate obtained in S2, wash it three times with absolute ethanol, and then perform low-temperature drying. The temperature of the low-temperature drying is 40 °C, and the time is 24 h to obtain antimony sulfide particles; place the antimony sulfide particles in a tubular furnace, under the condition of nitrogen protection, completely evacuate the high-purity nitrogen gas in the tube to keep the internal pressure of the tube at 1 MPa, and calcine at 250 °C for 1 h to obtain powdery nano-antimony sulfide with good crystallinity, with a weight of 11.41 g and a yield of 98.02%.

[0044] Example 3: A method for preparing antimony sulfide with good crystallinity, the preparation method comprising the following steps: S1. Dissolve the sulfur salt Mix 60 g of potassium sulfide and 10 g of antimony oxide evenly, place them in a dissolution tank, add pure water, and stir at a high speed to completely dissolve them. After adjusting the antimony concentration to 200 g / L, add a PVP dispersant, and mix evenly to obtain an antimony solution.

[0045] The rate of the high-speed stirring is 1500 rpm, and the stirring time is 20 min.

[0046] The addition amount of the PVP dispersant accounts for 5% of the mass of the antimony solution.

[0047] S2. Adjust the acidity Place the antimony solution in a constant-temperature water bath, control the temperature of the antimony solution at 5 °C, adjust the stirring rate to 800 rpm, and while stirring, turn on the peristaltic pump to slowly add an oxalic acid solution with a mass fraction of 40% at an addition rate of 2 ml / min. Control the final pH to be 9, and continue stirring and reacting for 6 h to obtain a precipitate.

[0048] S3. Filter and calcine Filter out the precipitate obtained in S2, wash it three times with absolute ethanol, and then perform low-temperature drying at 60 °C for 18 h to obtain antimony sulfide particles. Place the antimony sulfide particles in a tube furnace. Under the protection of nitrogen, completely evacuate the high-purity nitrogen gas in the tube to keep the internal pressure of the tube at 1.5 MPa, and calcine at 350 °C for 4 h to obtain powdery nano-antimony sulfide with good crystallinity, with a weight of 11.39 g and a yield of 97.85%.

[0049] Example 4: A method for preparing antimony sulfide with good crystallinity, the preparation method comprising the following steps: S1. Sulfur salt dissolution Mix 20 g of potassium sulfide and 10 g of antimony oxide evenly, place them in a dissolution tank, add pure water, and stir at a high speed to completely dissolve them. After adjusting the antimony concentration to 100 g / L, add CTAB dispersant, and mix evenly to obtain an antimony solution.

[0050] The rate of the high-speed stirring is 1400 rpm, and the stirring time is 30 min.

[0051] The addition amount of the CTAB dispersant accounts for 9% of the mass of the antimony solution.

[0052] S2. Adjust acidity Place the antimony solution in a constant-temperature water bath, control the temperature of the antimony solution at 15 °C, adjust the stirring rate to 1200 rpm, start a peristaltic pump to slowly add a 70% citric acid solution while stirring at a rate of 8 ml / min, control the end point pH to 7, and continue stirring and reacting for 3 h to obtain a precipitate.

[0053] S3. Filtration and calcination Filter out the precipitate obtained in S2, wash it three times with absolute ethanol, and then perform low-temperature drying at 50 °C for 22 h to obtain antimony sulfide particles. Place the antimony sulfide particles in a tube furnace. Under the protection of argon, completely evacuate the high-purity argon gas in the tube to keep the internal pressure of the tube at 0.5 MPa, and calcine at 300 °C for 3 h to obtain powdery nano-antimony sulfide with good crystallinity, with a weight of 11.17 g and a yield of 95.96%.

[0054] Example 5: A method for preparing antimony sulfide with good crystallinity, the preparation method comprising the following steps: S1. Sulfur salt dissolution Mix 80 g of ammonium sulfide and 10 g of antimony oxide evenly, place them in a dissolution tank, add pure water, and stir at a high speed to completely dissolve them. After adjusting the antimony concentration to 300 g / L, add CTAB dispersant, and mix evenly to obtain an antimony solution.

[0055] The rate of the high-speed stirring is 1500 rpm, and the stirring time is 20 min.

[0056] The addition amount of the CTAB dispersant accounts for 10% of the mass of the antimony solution.

[0057] S2. Adjust the acidity Place the antimony solution in a constant temperature water bath, control the temperature of the antimony solution at 0 °C, adjust the stirring rate to 400 rpm, while stirring, turn on the peristaltic pump and slowly add acetic acid solution with a mass fraction of 60% at an addition rate of 4 ml / min, control the end point pH to 3, and continue stirring and reacting for 1 h to obtain a precipitate.

[0058] S3. Filter and calcine Filter out the precipitate obtained in S2, wash it three times with absolute ethanol, and then perform low-temperature drying. The temperature of the low-temperature drying is 60 °C and the time is 18 h to obtain antimony sulfide particles; place the antimony sulfide particles in a tube furnace, under the protection of argon, completely evacuate the high-purity argon gas in the tube to keep the internal pressure of the tube at 1 MPa, and calcine at 200 °C for 5 h to obtain powdery nano-antimony sulfide with good crystallinity, with a weight of 11.46 g and a yield of 98.45%.

[0059] Example 6: A preparation method of antimony sulfide with good crystallinity, the preparation method comprising the following steps: S1. Dissolve the sulfur salt Mix 60 g of ammonium sulfide and 10 g of antimony oxide evenly, place them in a dissolution tank, add pure water, and stir at a high speed to completely dissolve them. After adjusting the antimony concentration to 150 g / L, add the CTAB dispersant, and mix evenly to obtain an antimony solution.

[0060] The rate of the high-speed stirring is 1300 rpm and the stirring time is 20 min.

[0061] The addition amount of the CTAB dispersant accounts for 1% of the mass of the antimony solution.

[0062] S2. Adjust the acidity Place the antimony solution in a constant temperature water bath, control the temperature of the antimony solution at 30 °C, adjust the stirring rate to 1000 rpm, while stirring, turn on the peristaltic pump and slowly add acetic acid solution with a mass fraction of 60% at an addition rate of 8 ml / min, control the end point pH to 1, and continue stirring and reacting for 5 h to obtain a precipitate.

[0063] S3. Filter and calcine The precipitate obtained in S2 was filtered out, washed three times with absolute ethanol, and then dried at a low temperature. The low-temperature drying temperature was 40 °C and the time was 24 h to obtain antimony sulfide particles. The antimony sulfide particles were placed in a tube furnace. Under the condition of argon protection, the high-purity argon gas in the tube was completely emptied to keep the tube pressure at 1 MPa, and calcined at 400 °C for 1 h to obtain powdery nano-antimony sulfide with good crystallinity, weighing 11.4 g and the yield being 97.94%.

[0064] The nano-antimony sulfide of Examples 1-3 was made into the negative electrode active material of a sodium-ion battery and its cycle number was tested. The specific method was as follows: The nano-antimony sulfide, conductive agent (carbon black) and binder (PVDF) were mixed evenly according to a mass ratio of 7:2:1, dispersed in N-methyl-2-pyrrolidone (NMP) to make an electrode slurry, which was coated on a copper foil, dried at 60 °C for 5 h, then roll-pressed and sliced, and finally vacuum-dried at 120 °C for 12 hours to obtain an electrode sheet; the loading amount of the antimony sulfide active substance on the electrode sheet was 1-1.5 mg / cm 2 。

[0065] In a glove box filled with argon, using the obtained electrode sheet as the working electrode and a sodium sheet as the counter electrode, a CR2025 type button battery was assembled. The electrolyte used was a propylene carbonate (PC) solution containing 1 mol / L of NaPF6 and 10 vol% of fluoroethylene carbonate (FEC), and the separator used was a Whatman glass fiber filter membrane; the assembled button battery was subjected to a constant current charge-discharge test on a charge-discharge tester. The voltage test range was 0.01-2.5 V. The cycle performance test procedure was to first form 200 cycles at a current of 100 mA / g, and then test the long-term cycle at a 2C current, and record the change in the specific capacity of the battery during the cycle.

[0066] From Figure 2 、 Figure 3 It can be seen that the particle size distribution of the powdery nano-antimony sulfide obtained after calcination is more uniform, indicating that the uncalcined antimony sulfide particles are amorphous, and the calcined nano-antimony sulfide has a crystal orientation; from Figure 4 、 Figure 5 It can be seen that the nano-antimony sulfide is a flaky structure with edge needle-like shapes and good dispersibility; from Figure 6 It can be seen that when the nano-antimony sulfide is made into the negative electrode active material of a sodium-ion battery, the specific capacity remains basically unchanged after long-term cycling.

[0067] Unless otherwise specified, the percentages described in the present invention are all mass percentages, and the ratios are all mass ratios; the raw materials are all commercially available.

[0068] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for preparing antimony sulfide with good crystallinity, characterized in that: The preparation method comprises the following steps: S1. Dissolution of sulfide salt: Mix sulfide salt and antimony oxide in proportion and place them in a dissolution tank, add pure water, stir at high speed to completely dissolve them, adjust the antimony concentration, add dispersant, mix well to obtain antimony solution; S2. Adjusting acidity: Control the temperature of the antimony solution to 0-30°C, slowly add the acid solution while stirring, control the endpoint pH, continue stirring the reaction for 1-6 hours to obtain a precipitate; S3, filtering and calcining: filtering the precipitate obtained in S2, washing it with anhydrous ethanol three times, and then drying it at low temperature to obtain antimony sulfide particles; calcining the antimony sulfide particles under the protection of inert gas to obtain nano antimony sulfide with good crystallinity.

2. The method for preparing antimony sulfide with good crystallinity according to claim 1, characterized in that: The sulfide salt in S1 is one of sodium sulfide, potassium sulfide or ammonium sulfide, and the mass ratio of the sulfide salt to antimony oxide is 2 to 8:

1.

3. The method for preparing antimony sulfide with good crystallinity according to claim 1, characterized in that: The antimony concentration in S1 is 50-300 g / L; The dispersant in S1 is one or more of ethylene glycol, PVP, and CTAB, and the added amount accounts for 1-10% of the mass of the antimony solution.

4. The method for preparing antimony sulfide with good crystallinity according to claim 1, characterized in that: The acid in the acid solution in S2 is one or more of hydrochloric acid, acetic acid, oxalic acid and citric acid.

5. The method for preparing antimony sulfide with good crystallinity according to claim 1, characterized in that: The mass fraction of the acid solution in S2 is 20-70%, and the adding rate is 2-10 ml / min.

6. The method for preparing antimony sulfide with good crystallinity according to claim 1, characterized in that: The end point pH in S2 is 1-9.

7. The method for preparing antimony sulfide with good crystallinity according to claim 1, characterized in that: The stirring rate in S2 is 400-1200 rpm, and the stirring reaction time is 1-6 hours.

8. The method for preparing antimony sulfide with good crystallinity according to claim 1, characterized in that: The calcination pressure in S3 is 0.5-2 MPa; The inert gas is nitrogen or argon.

9. The method for preparing antimony sulfide with good crystallinity according to claim 1, characterized in that: The calcination temperature in S3 is 150-400° C., and the calcination time is 1-5 hours.

10. Use of nano antimony sulfide prepared by the method for preparing antimony sulfide with good crystallinity as claimed in any one of claims 1 to 9, characterized in that: The nano antimony sulfide can be used as a negative electrode active material for sodium ion batteries.

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