A method for preparing hollow antimony trioxide and antimony-based electrode materials

Abstract

This invention relates to the field of electrochemistry, specifically to a method for preparing hollow antimony trioxide and an antimony-based electrode material. Antimony chloride is added to an alcohol solution and stirred until homogeneous to obtain solution A. Carbon microspheres are then added to obtain suspension B. 2-Methylimidazole is added to the alcohol solution and stirred until homogeneous to obtain solution C. Solution C is then added dropwise to suspension B under stirring. After the reaction, the mixture is filtered at room temperature to obtain a precursor. The precursor is calcined at 480-520℃ for 0.5-1 h to obtain hollow antimony trioxide. The hollow structure can buffer volume changes during charge-discharge cycles, significantly improving lithium storage characteristics and giving it excellent cycle stability. Testing shows that controlling the morphology of antimony trioxide and combining it with graphene can greatly improve its electrochemical performance and charge-discharge cycle stability, resulting in high electrochemical performance.

Description

Technical Field

[0001] This invention relates to the field of electrochemistry, specifically to a method for preparing hollow antimony trioxide and an antimony-based electrode material. Background Technology

[0002] The demand for green energy conversion and storage in various applications such as portable electronics, electric vehicles, and large power plants has driven researchers to explore advanced energy storage technologies. To meet diverse energy storage needs, designing and synthesizing green, recyclable, high-performance, and low-cost energy storage materials has become a current research hotspot. Since its commercialization, lithium-ion batteries have seen increasingly wider applications due to their high energy density, long cycle life, and environmental friendliness.

[0003] For a long time, antimony-based lithium-ion batteries have been considered the most promising candidates for anode materials in next-generation high-energy-density lithium-ion batteries due to their relatively low cost and excellent electrical performance. Antimony oxide has the highest theoretical capacity among all types of antimony-based electrode materials because the conversion and alloying reactions of antimony contribute high capacity during charging and discharging. Therefore, using antimony oxide as an electrode material for high-capacity lithium-ion batteries is of great significance. However, the volume changes of antimony oxide during cycling lead to poor structural stability and poor cycle stability, which to some extent limits its application as an electrode material. Summary of the Invention

[0004] Purpose of the invention: In view of the above-mentioned defects or improvement needs of the prior art, the present invention provides a method for preparing hollow antimony trioxide and an antimony-based electrode material.

[0005] The technical solution adopted in this invention is as follows:

[0006] A method for preparing hollow antimony trioxide includes the following steps:

[0007] S1: Add antimony chloride to an alcohol solution and stir until homogeneous to obtain solution A. Then add carbon microspheres and stir at 30-35℃ for 20-40 minutes to obtain suspension B. Add 2-methylimidazole to an alcohol solution and stir until homogeneous to obtain solution C.

[0008] S2: Heat suspension B to 40-45℃, and add solution C dropwise to suspension B while stirring. After the addition is complete, keep the temperature and stir for 5-10 hours, then heat to reflux and continue the reaction for 15-20 hours. Filter at room temperature, wash the solid with anhydrous ethanol and dry to obtain the precursor.

[0009] S3: The precursor is heated to 480-520℃ and calcined for 0.5-1h to obtain hollow antimony trioxide.

[0010] Furthermore, the alcohol solution in S1 is any one or a combination of methanol, ethanol, ethylene glycol, n-propanol, isopropanol, and glycerol.

[0011] Furthermore, the alcohol solution in S1 is a mixture of methanol and ethanol in a volume ratio of 1-5:1-5.

[0012] Furthermore, the alcohol solution in S1 is a mixture of methanol and ethanol in a 1:1 volume ratio.

[0013] Furthermore, the molar concentration of solution A in S1 is 0.1-0.15 mol / L, and the molar concentration of solution C is 0.2-0.5 mol / L.

[0014] Furthermore, the carbon microspheres in S1 have a particle size of 10-30 μm.

[0015] Furthermore, the heating rate during calcination in S3 is 2-5℃ / min.

[0016] An antimony-based electrode material is prepared by the following method:

[0017] Graphene is added to a nitric acid solution and ultrasonically dispersed for 30-50 minutes. Then, it is transferred to a reaction vessel and heated to 150-180℃ for 6-10 hours. After filtration at room temperature, the graphene is washed with water until neutral and then dried to obtain activated graphene. The activated graphene, hollow antimony trioxide, N-isopropylacrylamide, active agent, and water are mixed evenly, ultrasonicated for 20-30 minutes, stirred for 5-10 hours, and then filtered. The crosslinking agent and initiator are dissolved in water and poured into a funnel while being filtered. After the reaction is complete, the filtration is stopped, and the mixture is allowed to stand for 1-3 hours. The solid is then washed with water and dried.

[0018] Furthermore, the molar concentration of the nitric acid solution is 1-1.5 mol / L, and the mass ratio of graphene to nitric acid solution is 1:50-80.

[0019] Furthermore, the mass ratio of activated graphene, hollow antimony trioxide, and N-isopropylacrylamide is 60-80:20-40:1.

[0020] Furthermore, the active additives are polyvinylpyrrolidone and sodium dodecylbenzenesulfonate.

[0021] Furthermore, the active additive is a compound of polyvinylpyrrolidone and sodium dodecylbenzenesulfonate in a mass ratio of 3-5:1.

[0022] Furthermore, the crosslinking agent is any one of formaldehyde, glyoxal, ethylene glycol, glutaraldehyde, or N-methylenebisacrylamide, and the initiator is tetramethylethylenediamine and persulfate.

[0023] Persulfates are ammonium persulfate, sodium persulfate, or potassium persulfate;

[0024] The mass ratio of tetramethylethylenediamine to persulfate is 2-3:1.

[0025] The beneficial effects of this invention are:

[0026] During charge-discharge cycles, the volume changes of antimony oxide lead to poor structural stability and cycle stability. The inventors addressed this issue from two aspects. First, they prepared hollow antimony trioxide using a sacrificial template method. The hollow structure can buffer the volume changes during charge-discharge cycles, significantly improving lithium storage characteristics and giving it excellent cycle stability. Second, the inventors combined hollow antimony trioxide with graphene, which is also an effective method to solve the poor cycle stability of antimony trioxide. Graphene not only acts as a buffer to reduce powdering during cycling and as a conductive matrix, but its strength and flexibility also inhibit the movement of antimony trioxide particles during charge-discharge cycles. The large volume change in the graphene also forms an excellent synergistic effect and a strong binding effect, which improves conductivity. The inventors activated the graphene to give it active groups on its surface. With the help of active additives, it has better cohesion with hollow antimony trioxide, making the two tightly bonded. Poly(N-isopropylacrylamide) can further form a macromolecular chain network structure with active graphene and antimony trioxide, which increases the effective surface area of ​​the electrode material, reduces its internal resistance, and improves the cycling stability of the material. After testing, it was found that by controlling the morphology of antimony trioxide and combining it with graphene, its electrochemical performance can be greatly improved, its charge-discharge cycle stability can be improved, and it has high electrochemical performance. Attached Figure Description

[0027] Figure 1 This is a TEM image of the hollow antimony trioxide prepared in Example 1 of the present invention. Detailed Implementation

[0028] Unless otherwise specified in the examples, the procedures should be performed under standard conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0029] Example 1:

[0030] A method for preparing hollow antimony trioxide:

[0031] Antimony chloride (22.8 g, 0.1 mol) was added to 1 L of alcohol solution (methanol and ethanol mixed in a 1:1 volume ratio) and stirred until homogeneous to obtain solution A with a molar concentration of 0.1 mol / L. Then, 15 g of carbon microspheres with a particle size of 10-30 μm were added, and the mixture was stirred at 35 °C for 30 min to obtain suspension B. 2-methylimidazole (16.4 g, 0.2 mol) was added to 1 L of alcohol solution (methanol and ethanol mixed in a 1:1 volume ratio) and stirred until homogeneous to obtain solution C with a molar concentration of 0.2 mol / L. Suspension B was heated to 40 °C, and solution C was added dropwise to suspension B with stirring. After the addition was complete, the mixture was kept at the same temperature and stirred for 10 h, and then heated to reflux and continued to react for 15 h. The mixture was filtered at room temperature, and the solid was washed with anhydrous ethanol and dried to obtain the precursor. The precursor was heated to 500 °C at a rate of 3 °C / min and calcined for 1 h to obtain hollow antimony trioxide.

[0032] An antimony-based electrode material is prepared by the following method:

[0033] Graphene was added to a 1 mol / L nitric acid solution at a mass ratio of 1:60. After ultrasonic dispersion for 40 min, the solution was transferred to a high-temperature and high-pressure reactor, pressurized, and heated to 150°C for 8 h. The mixture was then filtered at room temperature, washed with water until neutral, and dried to obtain activated graphene. The activated graphene, the hollow antimony trioxide prepared above, N-isopropylacrylamide, polyvinylpyrrolidone, and sodium dodecylbenzenesulfonate (composed of an active agent in a mass ratio of 3:1), and water were mixed evenly, with the activated graphene, hollow antimony trioxide, and N-isopropylacrylamide having a mass ratio of 80:20:1. After ultrasonication for 30 min, the mixture was stirred for 10 h and filtered. An initiator composed of N-methylenebisacrylamide, tetramethylethylenediamine, and ammonium persulfate (composed of a mass ratio of 2:1) was dissolved in water and poured into a funnel, while simultaneously being filtered. After the reaction was complete, filtration was stopped, and the mixture was allowed to stand for 3 h. The solid was then washed with water and dried.

[0034] The performance of the prepared antimony-based electrode material was tested:

[0035] The electrochemical performance of the prepared antimony-based electrode material was measured using a three-electrode system with a Pt electrode as the counter electrode, a saturated calomel electrode as the reference electrode, and a 0.5 mol / L Na2SO4 aqueous solution as the electrolyte.

[0036] Test results show that the antimony-based electrode material can achieve a first discharge specific capacity of 1752 mAh / g at a current density of 100 mA / g and a voltage range of 0.01V-3V.

[0037] At a current density of 100 mA / g, the antimony-based electrode material retains 89.6% of its capacity after 3000 cycles, calculated from the second discharge capacity.

[0038] At a current density of 800 mA / g, the antimony-based electrode material retains 82.3% of its capacity after 3000 cycles, demonstrating excellent cycle stability.

[0039] Example 2:

[0040] The preparation method of hollow antimony trioxide is the same as in Example 1.

[0041] An antimony-based electrode material is prepared by the following method:

[0042] Graphene was added to a 1 mol / L nitric acid solution at a mass ratio of 1:80. After ultrasonic dispersion for 30 min, the solution was transferred to a high-temperature and high-pressure reactor, pressurized, and heated to 180°C for 6 h. The mixture was then filtered at room temperature, washed with water until neutral, and dried to obtain activated graphene. The activated graphene, the hollow antimony trioxide prepared above, N-isopropylacrylamide, polyvinylpyrrolidone, and sodium dodecylbenzenesulfonate (composed of an active agent in a mass ratio of 5:1), and water were mixed evenly, with the activated graphene, hollow antimony trioxide, and N-isopropylacrylamide having a mass ratio of 60:40:1. After ultrasonication for 20 min, the mixture was stirred for 10 h and filtered. An initiator composed of N-methylenebisacrylamide, tetramethylethylenediamine, and ammonium persulfate (composed of a mass ratio of 2:1) was dissolved in water and poured into a funnel, while simultaneously being filtered. After the reaction was complete, filtration was stopped, and the mixture was allowed to stand for 3 h. The solid was then washed with water and dried.

[0043] The performance of the prepared antimony-based electrode material was tested:

[0044] The electrochemical performance of the prepared antimony-based electrode material was measured using a three-electrode system with a Pt electrode as the counter electrode, a saturated calomel electrode as the reference electrode, and a 0.5 mol / L Na2SO4 aqueous solution as the electrolyte.

[0045] Test results show that the antimony-based electrode material can achieve an initial discharge specific capacity of 1740 mAh / g at a current density of 100 mA / g and a voltage range of 0.01V-3V.

[0046] At a current density of 100 mA / g, the capacity retention rate of the antimony-based electrode material after 3000 cycles, calculated from the second discharge capacity, is 89.1%.

[0047] At a current density of 800 mA / g, the antimony-based electrode material retains 82.6% of its capacity after 3000 cycles, demonstrating excellent cycle stability.

[0048] Example 3:

[0049] The preparation method of hollow antimony trioxide is the same as in Example 1.

[0050] An antimony-based electrode material is prepared by the following method:

[0051] Graphene was added to a 1.5 mol / L nitric acid solution at a mass ratio of 1:50. After ultrasonic dispersion for 50 min, the solution was transferred to a high-temperature and high-pressure reactor, pressurized, and heated to 150°C for 10 h. The mixture was then filtered at room temperature, washed with water until neutral, and dried to obtain activated graphene. The activated graphene, the hollow antimony trioxide prepared above, N-isopropylacrylamide, polyvinylpyrrolidone, and sodium dodecylbenzenesulfonate (composed of an active agent in a mass ratio of 3:1), and water were mixed evenly, with the activated graphene, hollow antimony trioxide, and N-isopropylacrylamide having a mass ratio of 80:20:1. After ultrasonication for 30 min, the mixture was stirred for 5 h and filtered. An initiator composed of N-methylenebisacrylamide, tetramethylethylenediamine, and ammonium persulfate (composed of a mass ratio of 3:1) was dissolved in water and poured into a funnel, while simultaneously being filtered. After the reaction was complete, filtration was stopped, and the mixture was allowed to stand for 1 h. The solid was then washed with water and dried.

[0052] The performance of the prepared antimony-based electrode material was tested:

[0053] The electrochemical performance of the prepared antimony-based electrode material was measured using a three-electrode system with a Pt electrode as the counter electrode, a saturated calomel electrode as the reference electrode, and a 0.5 mol / L Na2SO4 aqueous solution as the electrolyte.

[0054] Test results show that the antimony-based electrode material can achieve an initial discharge specific capacity of 1748 mAh / g at a current density of 100 mA / g and a voltage range of 0.01V-3V.

[0055] At a current density of 100 mA / g, the capacity retention rate of the antimony-based electrode material after 3000 cycles, calculated from the second discharge capacity, is 89.3%.

[0056] At a current density of 800 mA / g, the antimony-based electrode material retains 81.5% of its capacity after 3000 cycles, demonstrating excellent cycle stability.

[0057] Example 4:

[0058] The preparation method of hollow antimony trioxide is the same as in Example 1.

[0059] An antimony-based electrode material is prepared by the following method:

[0060] Graphene was added to a 1 mol / L nitric acid solution at a mass ratio of 1:50. After ultrasonic dispersion for 30 min, the solution was transferred to a high-temperature and high-pressure reactor, pressurized, and heated to 150°C for 6 h. The mixture was then filtered at room temperature, washed with water until neutral, and dried to obtain activated graphene. The activated graphene, the hollow antimony trioxide prepared above, N-isopropylacrylamide, polyvinylpyrrolidone, and sodium dodecylbenzenesulfonate (composed of an active agent in a mass ratio of 3:1), and water were mixed evenly, with the activated graphene, hollow antimony trioxide, and N-isopropylacrylamide having a mass ratio of 60:20:1. After ultrasonication for 20 min, the mixture was stirred for 5 h and filtered. An initiator composed of N-methylenebisacrylamide, tetramethylethylenediamine, and ammonium persulfate (composed of a mass ratio of 2:1) was dissolved in water and poured into a funnel, while simultaneously being filtered. After the reaction was complete, filtration was stopped, and the mixture was allowed to stand for 1 h. The solid was then washed with water and dried.

[0061] The performance of the prepared antimony-based electrode material was tested:

[0062] The electrochemical performance of the prepared antimony-based electrode material was measured using a three-electrode system with a Pt electrode as the counter electrode, a saturated calomel electrode as the reference electrode, and a 0.5 mol / L Na2SO4 aqueous solution as the electrolyte.

[0063] Test results show that the antimony-based electrode material can achieve an initial discharge specific capacity of 1740 mAh / g at a current density of 100 mA / g and a voltage range of 0.01V-3V.

[0064] At a current density of 100 mA / g, the antimony-based electrode material retains 87.8% of its capacity after 3000 cycles, calculated from the second discharge capacity.

[0065] At a current density of 800 mA / g, the antimony-based electrode material retains 81.4% of its capacity after 3000 cycles, demonstrating excellent cycle stability.

[0066] Example 5:

[0067] The preparation method of hollow antimony trioxide is the same as in Example 1.

[0068] An antimony-based electrode material is prepared by the following method:

[0069] Graphene was added to a 1.5 mol / L nitric acid solution at a mass ratio of 1:80. After ultrasonic dispersion for 50 min, the solution was transferred to a high-temperature and high-pressure reactor, pressurized, and heated to 180°C for 10 h. The mixture was then filtered at room temperature, washed with water until neutral, and dried to obtain activated graphene. The activated graphene, the hollow antimony trioxide prepared above, N-isopropylacrylamide, polyvinylpyrrolidone, and sodium dodecylbenzenesulfonate (composed of an active agent in a mass ratio of 5:1), and water were mixed evenly, with the activated graphene, hollow antimony trioxide, and N-isopropylacrylamide having a mass ratio of 80:40:1. After ultrasonication for 30 min, the mixture was stirred for 10 h and filtered. An initiator composed of N,N-methylenebisacrylamide, tetramethylethylenediamine, and ammonium persulfate (composed of a mass ratio of 3:1) was dissolved in water and poured into a funnel, while simultaneously being filtered. After the reaction was complete, filtration was stopped, and the mixture was allowed to stand for 3 h. The solid was then washed with water and dried.

[0070] The performance of the prepared antimony-based electrode material was tested:

[0071] The electrochemical performance of the prepared antimony-based electrode material was measured using a three-electrode system with a Pt electrode as the counter electrode, a saturated calomel electrode as the reference electrode, and a 0.5 mol / L Na2SO4 aqueous solution as the electrolyte.

[0072] Test results show that the antimony-based electrode material can achieve a first discharge specific capacity of 1750 mAh / g at a current density of 100 mA / g and a voltage range of 0.01V-3V.

[0073] At a current density of 100 mA / g, the antimony-based electrode material retains 89.4% of its capacity after 3000 cycles, calculated from the second discharge capacity.

[0074] At a current density of 800 mA / g, the antimony-based electrode material retains 81.5% of its capacity after 3000 cycles, demonstrating excellent cycle stability.

[0075] Comparative Example 1

[0076] Comparative Example 1 is basically the same as Example 1, except that commercially available antimony trioxide (brand: Kepler, CAS: 1309-64-4, model: kpl-633260) is used instead of the self-made hollow antimony trioxide.

[0077] The performance of the prepared antimony-based electrode material was tested:

[0078] The electrochemical performance of the prepared antimony-based electrode material was measured using a three-electrode system with a Pt electrode as the counter electrode, a saturated calomel electrode as the reference electrode, and a 0.5 mol / L Na2SO4 aqueous solution as the electrolyte.

[0079] Test results show that the antimony-based electrode material can achieve an initial discharge specific capacity of 1470 mAh / g at a current density of 100 mA / g and a voltage range of 0.01V-3V.

[0080] At a current density of 100 mA / g, the capacity retention rate of the antimony-based electrode material after 3000 cycles, calculated from the second discharge capacity, is 75.2%.

[0081] At a current density of 800 mA / g, the antimony-based electrode material retains 66.3% of its capacity after 3000 cycles, demonstrating excellent cycle stability.

[0082] Comparative Example 2

[0083] Comparative Example 2 is basically the same as Example 1, except that the graphene is not activated.

[0084] The performance of the prepared antimony-based electrode material was tested:

[0085] The electrochemical performance of the prepared antimony-based electrode material was measured using a three-electrode system with a Pt electrode as the counter electrode, a saturated calomel electrode as the reference electrode, and a 0.5 mol / L Na2SO4 aqueous solution as the electrolyte.

[0086] Test results show that the antimony-based electrode material can achieve a first discharge specific capacity of 1605 mAh / g at a current density of 100 mA / g and a voltage range of 0.01V-3V.

[0087] At a current density of 100 mA / g, the antimony-based electrode material retains 83.4% of its capacity after 3000 cycles, calculated from the second discharge capacity.

[0088] At a current density of 800 mA / g, the antimony-based electrode material retains 77.5% of its capacity after 3000 cycles, demonstrating excellent cycle stability.

[0089] 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. An antimony-based electrode material, characterized in that, Its preparation method is as follows: Graphene was added to a nitric acid solution and ultrasonically dispersed for 30-50 minutes. The mixture was then transferred to a reaction vessel and heated to 150-180℃ for 6-10 hours. After filtration at room temperature, the graphene was washed with water until neutral and then dried to obtain activated graphene. The activated graphene, hollow antimony trioxide, N-isopropylacrylamide, active additives, and water were mixed evenly, ultrasonicated for 20-30 minutes, stirred for 5-10 hours, and then filtered. The crosslinking agent and initiator were dissolved in water and poured into a funnel while simultaneously filtering. After the reaction was complete, filtration was stopped, and the mixture was allowed to stand for 1-3 hours. The solid was then washed with water and dried. The mass ratio of activated graphene, hollow antimony trioxide, and N-isopropylacrylamide is 60-80:20-40:1; The method for preparing the hollow antimony trioxide is as follows: S1: Add antimony chloride to an alcohol solution and stir until homogeneous to obtain solution A. Then add carbon microspheres and stir at 30-35℃ for 20-40 minutes to obtain suspension B. Add 2-methylimidazole to an alcohol solution and stir until homogeneous to obtain solution C. S2: Heat suspension B to 40-45℃, and add solution C dropwise to suspension B while stirring. After the addition is complete, keep the temperature and stir for 5-10 hours, then heat to reflux and continue the reaction for 15-20 hours. Filter at room temperature, wash the solid with anhydrous ethanol and dry to obtain the precursor. S3: The precursor is heated to 480-520℃ and calcined for 0.5-1h to obtain hollow antimony trioxide; The active additives are polyvinylpyrrolidone and sodium dodecylbenzenesulfonate.

2. The antimony-based electrode material as described in claim 1, characterized in that, The alcohol solution in S1 is any one or a combination of methanol, ethanol, ethylene glycol, n-propanol, isopropanol, and glycerol.

3. The antimony-based electrode material as described in claim 1, characterized in that, In S1, the molar concentration of solution A is 0.1-0.15 mol / L, and the molar concentration of solution C is 0.2-0.5 mol / L.

4. The antimony-based electrode material as described in claim 1, characterized in that, The carbon microspheres in S1 have a particle size of 10-30 μm.

5. The antimony-based electrode material as described in claim 1, characterized in that, The heating rate during calcination in S3 is 2-5℃ / min.

6. The antimony-based electrode material as described in claim 1, characterized in that, The molar concentration of the nitric acid solution is 1-1.5 mol / L, and the mass ratio of graphene to nitric acid solution is 1:50-80.

7. The antimony-based electrode material as described in claim 1, characterized in that, The crosslinking agent is any one of formaldehyde, glyoxal, ethylene glycol, glutaraldehyde, or N,N-methylenebisacrylamide, and the initiator is tetramethylethylenediamine and persulfate.

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