Preparation method of Ni3S2 / C composite material for sodium ion battery negative electrode material

Abstract

The invention provides a preparation method of a Ni3S2 / C composite material for a sodium-ion battery negative electrode material, and aims to improve the electrochemical performance of a sawdust negative electrode material. The method comprises the following steps: 1, putting wood chips into a tubular furnace, carrying out pre-carbonization treatment in an inert gas atmosphere, cooling, and carrying out ball milling; 2, putting the pretreated sample into a constant-temperature stirrer, adding a nickel sulfate hexahydrate solution while stirring, uniformly stirring, and drying; 3, putting the obtained sample into a tubular furnace, carrying out high-temperature reaction treatment in an inert gas atmosphere, and then cooling to room temperature; 4, immersing the treated sample into a diluted hydrochloric acid solution, stirring, filtering, washing and drying; and 5, carrying out high-temperature carbonization treatment on the obtained sample in an inert gas atmosphere, and cooling to room temperature to obtain the Ni3S2 / C composite negative electrode material. The method is simple in process, the prepared Ni3S2 / C composite material has excellent electrochemical performance, and the specific capacity and the cycling stability can be effectively improved.

Description

Technical Field The invention relates to a method for preparing a Ni3S2 / C composite material for a negative electrode material of a sodium ion battery. Background Art

[0001] As the global energy crisis and environmental pollution become increasingly serious, the development of sustainable and economical energy storage technologies has become an important issue. Sodium-ion batteries (SIBs) are considered to be an ideal alternative to lithium-ion batteries, especially in the field of large-scale energy storage, due to their abundant and cheap sodium resources. However, the performance of sodium-ion battery anode materials, especially specific capacity, cycle stability and charge and discharge rate, is still a key factor limiting its commercial application. At present, the negative electrode materials of sodium ion batteries mainly include carbon materials, metal alloys, metal oxides and sulfides, among which biomass-based carbon materials have attracted widespread attention due to their adjustable structure, excellent electrochemical performance and low cost. The combination of sulfide and carbon materials can effectively improve the electrochemical performance of negative electrode materials. Ni3S2 has become a potential candidate material for the negative electrode of sodium ion batteries due to its high specific capacity and excellent conductivity. By loading carbon materials (such as graphene, activated carbon, etc.) on the surface of Ni3S2, its electrochemical performance can be further enhanced. Summary of the invention

[0002] The present invention aims to improve the performance of negative electrode materials for sodium ion batteries and provides a method for preparing a Ni3S2 / C composite material suitable for use in sodium ion batteries. In order to achieve the above object, the present invention provides a method for preparing a Ni3S2 / C composite material for a sodium ion battery, which specifically comprises the following steps: 1. Wash the sawdust (nanmu, tung wood, birch, apple wood), remove impurities and dry it. Put the sawdust into a quartz boat and place it in a tube furnace (or box furnace). Heat it to 200-700℃ in an inert gas (nitrogen or argon) atmosphere for pre-carbonization. The heating rate is 1-10℃ / min, and keep it warm for 1-5h, and cool it to room temperature with the furnace. The pre-carbonized sample is ball-milled according to the material ball mass ratio of 1:1-10, the ball milling speed is 300-500r / min, the ball milling time is 1-6h, and the solvent is water. 2. Add the sample obtained in step 1 and nickel sulfate hexahydrate to a beaker filled with deionized water in sequence, and stir evenly in a constant temperature stirrer. The mass ratio of the sample obtained in step 1 to nickel sulfate hexahydrate is 1:0.01 to 10. Then treat the solution in a water bath at a temperature of 50 to 100°C for 3 to 10 hours until the water evaporates, and then dry the sample in a drying oven at 50 to 100°C. 3. Take the sample obtained in step 2, put it into a quartz boat, and place it in a tube furnace (or box furnace). In an inert gas (nitrogen or argon) atmosphere, heat it in stages to 400-800°C at a heating rate of 1-10°C / min, keep it warm for 1-5 hours, and cool it to room temperature with the furnace. 4. Soak the sample obtained in step 3 in a dilute hydrochloric acid solution and stir it on a constant temperature stirrer for 1 to 12 hours. After soaking, filter and wash it, use deionized water and ethanol to wash it until the pH value is about 7, and finally dry it in a drying oven at 50 to 100°C. 5. Put the sample obtained in step 4 into a quartz boat, and place it in a tube furnace (or box furnace), and heat it to 900-1700℃ in a staged manner under an inert gas (nitrogen or argon) atmosphere at a heating rate of 1-10℃ / min, and keep it warm for 1-5h, and cool it to room temperature with the furnace. Then, Ni3S2 / C composite material can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 This is the XRD diagram of the material obtained in Experiment 1 of the present invention. Figure 2 This is the first charge and discharge curve of the CR2016 sodium ion button battery assembled with the material prepared in Experiment 1 of the present invention at a current density of 20 mA / g. Figure 3 This is the first charge and discharge curve of the CR2016 sodium ion button battery assembled with the material prepared in Experiment 1 of the present invention at a current density of 20 mA / g. DETAILED DESCRIPTION

[0003] The technical solution of the present invention is not limited to the specific implementation modes listed below, but also includes any combination of the specific implementation modes.

[0004] Specific implementation method 1: A method for preparing a Ni3S2 / C composite material for a negative electrode material of a sodium ion battery is carried out according to the following steps: 1. Wash the nanmu chips, remove impurities and dry them, put them in a quartz boat, and place them in a tube furnace (or box furnace), heat them to 300℃ in an inert gas (nitrogen or argon) atmosphere, at a heating rate of 5℃ / min, and keep them warm for 2h, and cool them to room temperature with the furnace. Then, ball mill them at a material ball mass ratio of 1:1, at a speed of 300r / min, for 5h, and the solvent is water. 2. Add the sample obtained in step 1 and nickel sulfate hexahydrate to a beaker filled with deionized water in sequence, and stir evenly in a constant temperature stirrer. The mass ratio of the sample obtained in step 1 to nickel sulfate hexahydrate is 1:0.5. Then, the solution is treated with a water bath at a temperature of 85°C for 5 hours until the water evaporates, and then the sample is placed in a drying oven at 80°C to dry. 3. Take the sample obtained in step 2 and put it into a quartz boat, and place it in a tube furnace (or box furnace). Heat it to 600°C in an inert gas (nitrogen or argon) atmosphere at a heating rate of 5°C / min, keep it warm for 2 hours, and cool it to room temperature with the furnace. 4. Pour the sample obtained in step 3 into a dilute hydrochloric acid solution, stir on a constant temperature stirrer, soak for 2 hours, then filter and wash, wash with deionized water until the pH is 6.5-7, and finally place the sample in a drying oven at 80°C to dry. 5. Put the sample obtained in step 4 into a quartz boat, and place it in a tube furnace (or box furnace), and heat it to 1200℃ in a staged manner under an inert gas (nitrogen or argon) atmosphere at a heating rate of 5℃ / min, and keep it warm for 2h, and cool it to room temperature with the furnace. Then, Ni3S2 / C composite material can be obtained.

[0005] Specific embodiment 2: This embodiment is different from the specific embodiment 1 in that the pre-carbonization temperature in step 1 is 400° C. The other steps and parameters are the same as those in the specific embodiment 1.

[0006] Specific implementation method three: This implementation method is different from specific implementation method one or method two in that the mass ratio of the balls in step one is 1:5. The other steps and parameters are the same as those in specific implementation method one.

[0007] Specific embodiment 4: This embodiment differs from specific embodiments 1 to 3 in that the mass ratio of the sample obtained in step 2 to nickel sulfate hexahydrate is 1:1. Other steps and parameters are the same as those in specific embodiment 1.

[0008] Specific implementation example 5: This implementation example is different from specific implementation examples 1 to 4 in that the temperature in step 3 is 800° C. and the heating rate is 5° C. / min. The other steps and parameters are the same as those in specific implementation example 1.

[0009] Specific implementation example 6: This implementation example is different from specific implementation examples 1 to 5 in that the temperature in step 4 is 1200° C. and the heating rate is 10° C. / min. The other steps and parameters are the same as those in specific implementation example 1. Experimental verification

[0010] The following experiments were used to verify the effect of the present invention: Experiment 1: A method for preparing a Ni3S2 / C composite material for a sodium ion battery is carried out according to the following steps: 1. Wash the nanmu chips, remove impurities and dry them, put them in a quartz boat, and place them in a tube furnace. Heat them to 300℃ in a nitrogen atmosphere at a heating rate of 5℃ / min, keep them warm for 2h, and cool them to room temperature with the furnace. Then, ball mill them at a material ball mass ratio of 1:1, with a rotation speed of 300r / min, a ball milling time of 5h, and water as the solvent. 2. The sample obtained in step 1 and nickel sulfate hexahydrate are added to a beaker filled with deionized water in sequence, and stirred evenly in a constant temperature stirrer. The mass ratio of the sample obtained in step 1 to nickel sulfate hexahydrate is 1:0.25. The solution is then treated with a water bath at a temperature of 85°C for 5 hours until the water evaporates, and then the sample is placed in a drying oven at 80°C for drying. 3. Take the sample obtained in step 2, put it into a quartz boat, and place it in a tube furnace. Heat it to 600°C in a nitrogen atmosphere at a heating rate of 5°C / min, keep it warm for 2 hours, and cool it to room temperature with the furnace. 4. Pour the sample obtained in step 3 into a dilute hydrochloric acid solution, stir on a constant temperature stirrer, soak for 2 hours, then filter and wash, wash with deionized water until the pH is about 7, and finally place the sample in a drying oven at 80°C to dry. 5. After drying the sample obtained in step 4 at 80°C, put it into a quartz boat, and place it in a tube furnace (or box furnace), heat it to 1200°C in a nitrogen atmosphere at a heating rate of 5°C / min, and keep it warm for 2h, and cool it to room temperature with the furnace. Ni3S2 / C composite material is obtained.

[0011] Experiment 2: A method for preparing a Ni3S2 / C composite material for a sodium ion battery is carried out according to the following steps: 1. Wash the nanmu chips, remove impurities and dry them, put them in a quartz boat, put them in a tube furnace, heat them to 300℃ in a nitrogen atmosphere, the heating rate is 5℃ / min, keep them warm for 2h, and cool them to room temperature with the furnace. Then, ball mill them at a material ball mass ratio of 1:1, the speed is 300r / min, the ball milling time is 5h, and the solvent is water. 2. The sample obtained in step 1 and nickel sulfate hexahydrate are added to a beaker filled with deionized water in sequence, and stirred evenly in a constant temperature stirrer. The mass ratio of the sample obtained in step 1 to nickel sulfate hexahydrate is 1:0.16. The solution is then treated with a water bath at a temperature of 85°C for 5 hours until the water evaporates, and then the sample is placed in a drying oven at 80°C for drying. 3. Take the sample obtained in step 2, put it into a quartz boat, and place it in a tube furnace. Heat it to 600°C in a nitrogen atmosphere at a heating rate of 5°C / min, keep it warm for 2 hours, and cool it to room temperature with the furnace. 4. Pour the sample obtained in step 3 into a dilute hydrochloric acid solution, stir on a constant temperature stirrer, soak for 2 hours, then filter and wash, wash with deionized water until the pH is about 7, and finally place the sample in a drying oven at 80°C to dry. 5. After drying the sample obtained in step 4 at 80°C, put it into a quartz boat, and place it in a tube furnace (or box furnace), heat it to 1200°C in a nitrogen atmosphere at a heating rate of 5°C / min, and keep it warm for 2h, and cool it to room temperature with the furnace. Ni3S2 / C composite material is obtained. Experimental results show that the Ni3S2 / C composite material exhibits excellent electrochemical performance in sodium ion batteries, has a high specific capacity and good cycle stability, and is suitable for use as a negative electrode in sodium ion batteries.

Claims

1. A method for preparing a Ni3S2 / C composite material for a negative electrode material of a sodium ion battery, characterized in that: The following steps are involved:

1. Put the cleaned sawdust into a tubular furnace and perform pre-carbonization treatment under an inert gas atmosphere. After the treatment, cool it naturally and then perform ball milling until a powdery material is obtained; 2. Add the sample obtained in step 1 and nickel sulfate hexahydrate in a certain mass ratio into a beaker filled with deionized water, stir evenly, and then place in a water bath until the water evaporates, and then dry the sample; 3. Place the sample obtained in step 2 into a tube furnace, perform a high temperature reaction treatment under an inert gas atmosphere, and cool it naturally after the treatment is completed; 4. Soak the sample obtained in step 3 in a dilute hydrochloric acid solution and stir it in a constant temperature stirrer, then filter, wash and dry the sample; 5. Place the sample obtained in step 4 into a tubular furnace and perform high-temperature carbonization treatment under an inert gas atmosphere. After the treatment is completed, cool it naturally to obtain a Ni3S2 / C composite material, which is ultimately used as the negative electrode of a sodium ion battery.

2. The method according to claim 1, characterized in that: In step 1, the sawdust is one of nanmu, paulownia, birch or apple wood, the pre-carbonization treatment temperature is 200-700° C., the heating rate is 1-10° C. / min, and the insulation time is 1-5 hours.

3. The method according to claim 1, characterized in that The mass ratio of the sample obtained in step 2 to nickel sulfate hexahydrate is 1:0.01-10, the temperature of the water bath treatment is 50-100° C., and the hydrothermal time is 3-10 hours.

4. The method according to claim 1, characterized in that: In step 3, the temperature of the high temperature reaction treatment is 400-800° C., the heating rate is 1-10° C. / min, and the insulation time is 1-5 hours.

5. The method according to claim 1, characterized in that: The acid soaking time of the sample in step 4 is 1 to 12 hours.

6. The method according to claim 1, characterized in that In step 5, the temperature of the high temperature carbonization treatment is 900-1700° C., the heating rate is 1-10° C. / min, and the insulation time is 1-5 hours.

7. The method according to claim 1, characterized in that The ball milling time in step 1 is 1 to 6 hours, the ball mass ratio is 1:1 to 10, and the ball milling solvent is water.

8. A method for preparing a Ni3S2 / C composite material for a negative electrode material of a sodium ion battery, characterized in that: Prepared by the method according to any one of claims 1 to 7.

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