Preparation Method and Application of Anode Material for Sodium-Ion Batteries

Abstract

The present disclosure relates to the technical field of sodium-ion batteries, and discloses a preparation method and application of a negative electrode material for a sodium-ion battery. Ammonia solution is dropped into a mixed solution containing a tin salt and a nickel salt, and heated for reaction to obtain NiSn(OH)6 nanospheres. The NiSn(OH)6 nanospheres are dispersed in a solvent, and thioacetamide is added, and heated for reaction to obtain flower-shaped nanospheres SnS2-NiS. The flower-shaped nanospheres SnS2-NiS, biochar, and binder are mixed in water, heated for reaction, subjected to solid-liquid separation, the obtained solid is dried, and then sintered under an inert atmosphere to obtain the negative electrode material for the sodium-ion battery.

Description

Technical Field

[0001] The present disclosure belongs to the technical field of sodium ion batteries, and particularly relates to a preparation method and application of a negative electrode material for a sodium ion battery. Background Art

[0002] Lithium ion batteries have achieved great success in the past two decades. Lithium ion batteries have been widely used in electronic devices, electric vehicles and other facilities and penetrated into all aspects of life. However, due to the limitation of lithium resources, the large-scale application and sustainable development of lithium ion batteries are restricted. Therefore, there is an urgent need to develop alternative energy storage systems. Considering that sodium ion batteries have lower energy density and voltage than lithium ion batteries, sodium ion batteries can be used in situations where there are no high requirements for volume and portability. Sodium ion batteries have the characteristics of low cost, good interfacial ion diffusion ability, high ionic conductivity, excellent high and low temperature performance, good safety performance, etc.

[0003] Although sodium ion batteries have the above advantages, there are still some problems to be solved. Among them, the negative electrode material has very serious volume expansion during charge and discharge, which even leads to electrode fragmentation, pulverization and poor cycle performance. At present, the main method to solve these problems is to use a sodium alloy that can form an alloy with sodium as the negative electrode material. Although the initial capacity of the alloy material is high, with the progress of cycling, the volume expansion of the alloy leads to a sharp reduction in cycle stability. Therefore, it is necessary to solve the problems of volume expansion and poor conductivity of the negative electrode material.

[0004] Therefore, there is an urgent need to find a negative electrode material with excellent cycle stability, long life and high rate performance to solve the problems of volume expansion and poor conductivity of the negative electrode material. Summary of the Invention

[0005] The present disclosure aims to at least solve one of the technical problems existing in the above prior art. For this purpose, the present disclosure provides a preparation method and application of a negative electrode material for a sodium ion battery.

[0006] According to one aspect of the present disclosure, a preparation method of a negative electrode material is provided, including the following steps:

[0007] S1: Drop ammonia solution into a mixed solution containing stannous salt and nickel salt, and then heat and react to obtain NiSn(OH) 6 nanospheres; the reaction equation is Sn 4+ +Ni 2+ +6OH - →NiSn(OH) 6 ;

[0008] S2: The NiSn(OH) 6The nanospheres are dispersed in a solvent, thioacetamide is added, and then the reaction is carried out by heating to obtain flower-shaped nanospheres SnS 2 -NiS, and the NiSn(OH) 6 The molar ratio of the nanospheres to the thioacetamide is 1:(3 - 5); to synthesize flower-shaped nanospheres, only an excessive amount of thioacetamide needs to be added. When the molar ratio of thioacetamide to NiSn(OH) 6 is greater than 3, a flower-shaped structure can be synthesized. The reaction equation is: 3CH 3 CSNH 2 +NiSn(OH) 6 →SnS 2 -NiS+3CH 3 CONH 2 +3H 2 O;

[0009] S3: The flower-shaped nanospheres SnS 2 -NiS, biochar, and binder are mixed in water, the reaction is carried out by heating, then solid-liquid separation is performed, the obtained solid is dried, and then sintering is carried out under an inert atmosphere to obtain the negative electrode material.

[0010] In some embodiments of the present disclosure, in step S1, the molar ratio of the tin salt to the nickel salt is 1:(1 - 1.5).

[0011] In some embodiments of the present disclosure, in step S1, after dropping the ammonia solution, stirring is carried out for 1 - 4 h, and then the reaction is carried out by heating.

[0012] In some embodiments of the present disclosure, in step S1, the temperature of the heating reaction is 100 - 200 °C; the time of the heating reaction is 6 - 12 h.

[0013] In some embodiments of the present disclosure, in step S1, after the heating reaction, it further includes washing the NiSn(OH) 6 nanospheres with water and ethanol, and then drying at 60 - 70 °C for 6 - 12 h.

[0014] In some embodiments of the present disclosure, in step S1, the tin salt is at least one of SnCl 4 , Na 2 SnO 3 or Sn(NO 3 ) 4 .

[0015] In some embodiments of the present disclosure, in step S1, the nickel salt is at least one of Ni(CH 3 COO) 2 , nickel sulfate or nickel chloride.

[0016] In some embodiments of the present disclosure, in step S2, the temperature of the heating reaction is 150 - 200 °C; the time of the heating reaction is 18 - 24 h.

[0017] In some embodiments of the present disclosure, in step S2, the solvent is at least one of absolute ethanol, propanol or pentanol.

[0018] In some embodiments of the present disclosure, in step S2, after adding the thioacetamide, ultrasonication is performed for 2 - 6 h first, and then the heating reaction is carried out.

[0019] In some embodiments of the present disclosure, in step S2, after the heating reaction, it further includes washing the flower-shaped nanospheres with water and ethanol, and freeze-drying for 22 - 24 h.

[0020] In some embodiments of the present disclosure, in step S2, the particle size D50 of the flower-shaped nanospheres SnS 2 -NiS is 80 - 120 nm.

[0021] In some embodiments of the present disclosure, in step S3, the particle size D50 of the biochar is 6 - 15 μm.

[0022] In some embodiments of the present disclosure, in step S3, the mass ratio of the flower-shaped nanospheres SnS 2 -NiS, biochar, and binder is (1 - 2):(10 - 20):(0.5 - 1).

[0023] In some embodiments of the present disclosure, in step S3, the sintering temperature is 700 - 900 °C. The sintering time is 4 - 12 h.

[0024] In some embodiments of the present disclosure, in step S3, the binder is at least one of glucose or sucrose.

[0025] In some embodiments of the present disclosure, in step S3, the temperature of the heating reaction is 55 - 85 °C, and the time is 2 - 6 h.

[0026] In some embodiments of the present disclosure, the preparation method of the biochar in step S3 is as follows: (1) impregnate the biomass raw material in a KOH solution, and then wash, dry, and grind it to obtain a ground material; (2) pyrolyze the ground material under anaerobic conditions, and wash and dry it to obtain the biochar. Further preferably, the mass fraction of the KOH solution is 10 - 20%; the impregnation time is 24 - 48 h; the particle size of the ground material is 100 - 200 mesh; the pyrolysis temperature is 550 - 750 °C, and the pyrolysis time is 2 - 4 h.

[0027] In some preferred embodiments of the present disclosure, when preparing the biochar, in step (1), the biomass raw material is at least one of rice husk, wheat straw or wood chips.

[0028] The present disclosure also provides the application of the negative electrode material prepared by the preparation method in a sodium ion battery.

[0029] According to a preferred embodiment of the present disclosure, it has at least the following beneficial effects:

[0030] 1. During the charge and discharge process of a sodium ion battery, the insertion / extraction of sodium ions easily causes volume expansion of the negative electrode material. The biochar of the present disclosure provides a self-buffering space for the expansion.

[0031] 2. The SnS 2 -NiS flower-like structure enables the entire electrode to have sufficient Na + active sites and contact area with the electrolyte, which can buffer volume expansion and shorten the diffusion length of Na + ions.

[0032] 3. The internal pore size of the biochar is rich, enabling the SnS 2 -NiS particles to be evenly distributed on the internal pore size, effectively preventing the aggregation of SnS 2 -NiS particles and increasing the capacity of the sodium ion battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The following will further illustrate the present disclosure in conjunction with the drawings and embodiments, where:

[0034] Figure 1 is the SEM image of the flower-like nanospheres SnS 2 -NiS prepared in Example 1 of the present disclosure. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] The following will clearly and completely describe the concept and technical effects generated by the present disclosure in conjunction with the embodiments to fully understand the purpose, features and effects of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of the present disclosure without creative efforts shall fall within the scope of protection of the present disclosure.

[0036] Example 1

[0037] In this example, a negative electrode material for a sodium ion battery was prepared, and the specific process was as follows:

[0038] (1) 10 g of rice husk was added to 100 mL of a 10% KOH solution by mass and impregnated for 24 h, washed with water until neutral, dried and ground to obtain a ground material;

[0039] (2) Add the abrasive in step (1) to a muffle furnace, pyrolyze it at 550 °C for 2 h under a nitrogen atmosphere, then wash it with deionized water until neutral, and dry it to obtain biochar with a particle size D50 of 8.5 μm;

[0040] (3) Add 1 mol of Na 2 SnO 3 and 1 mol of Ni(CH 3 COO) 2 to an aqueous deionized solution, then dropwise add an ammonia solution, stir slowly for 1 h, finally, transfer the mixture to a 100 mL autoclave, and heat it at 100 °C for 6 h, wash it with deionized water and ethanol, and then dry it at 60 °C for 6 h to obtain NiSn(OH) 6 nanospheres for collection and standby;

[0041] (4) Dissolve 1 mol of NiSn(OH) 6 nanospheres prepared in step (3) in absolute ethanol by ultrasonic treatment, add 3 mol of thioacetamide under stirring conditions, ultrasonically treat the mixture for 2 h, then transfer it to an autoclave, and heat it at 150 °C for 18 h, wash it with deionized water and ethanol, and freeze-dry it for 24 h to obtain flower-shaped nanospheres SnS 2 -NiS with a particle size D50 of 92 nm;

[0042] (5) Add 10 g of biochar and 1 g of flower-shaped nanospheres SnS 2 -NiS to deionized water, add 0.5 g of glucose, and react at 55 °C for 2 h. After centrifugation and drying, sinter it at 700 °C for 4 h under an Ar atmosphere to obtain the negative electrode material SnS 2 -NiS@C for sodium-ion batteries.

[0043] Example 2

[0044] In this example, a negative electrode material for a sodium-ion battery was prepared. The specific process was as follows:

[0045] (1) Immerse 12 g of rice husk in 100 mL of a 10% KOH solution by mass for 24 h, wash it with water until neutral, dry it and grind it to obtain an abrasive;

[0046] (2) Add the abrasive in step (1) to a muffle furnace, pyrolyze it at 600 °C for 2.5 h under a nitrogen atmosphere, then wash it with deionized water until neutral, and dry it to obtain biochar with a particle size D50 of 9 μm;

[0047] (3) Add 1 mol of Na 2 SnO 3 and 1.2 mol of Ni(CH 3 COO)2 It was added to deionized aqueous solution, then ammonia solution was added dropwise, and then stirred slowly for 2 h. Finally, the mixture was transferred to a 100 mL autoclave and heated at 120 °C for 8 h, washed with deionized water and ethanol, and then dried at 60 °C for 8 h to obtain NiSn(OH) 6 nanospheres for collection and standby;

[0048] (4) 1 mol of NiSn(OH) prepared in step (3) was dissolved in absolute ethanol by ultrasonic treatment. Under stirring conditions, 3.5 mol of thioacetamide was added, and the mixture was ultrasonicated for 3 h, then transferred to an autoclave and heated at 160 °C for 20 h, washed with deionized water and ethanol, and freeze-dried for 24 h to obtain flower-like nanospheres SnS 6 -NiS with a D50 particle size of 110 nm; 2 -NiS;

[0049] (5) 12 g of biochar and 1.2 g of flower-like nanospheres SnS 2 -NiS were added to deionized water, 0.6 g of glucose was further added, and the reaction was carried out at 60 °C for 3 h. After centrifugation and drying, it was sintered at 750 °C for 6 h under an Ar atmosphere to obtain the anode material SnS 2 -NiS@C for sodium-ion batteries.

[0050] Example 3

[0051] An anode material for sodium-ion batteries was prepared in this example. The specific process was as follows:

[0052] (1) 13 g of wheat straw was added to 100 mL of 10% KOH solution by mass and impregnated for 30 h, washed with water until neutral, dried and ground to obtain a grinding material;

[0053] (2) The grinding material obtained in step (1) was added to a muffle furnace and pyrolyzed at 620 °C for 3 h under a nitrogen atmosphere, then washed with deionized water until neutral and dried to obtain biochar with a D50 particle size of 7 μm;

[0054] (3) 1 mol of Na 2 SnO 3 and 1.4 mol of Ni(CH 3 COO) 2 were added to deionized aqueous solution, then ammonia solution was added dropwise, and then stirred slowly for 3 h. Finally, the mixture was transferred to a 100 mL autoclave and heated at 150 °C for 10 h, washed with deionized water and ethanol, and then dried at 60 °C for 10 h to obtain NiSn(OH) 6 nanospheres for collection and standby;

[0055] (4) Dissolve 1 mol of NiSn(OH) prepared in step (3) 6 nanospheres in absolute ethanol, add 4 mol of thioacetamide under stirring conditions, ultrasonicate the mixture for 3 h, then transfer it to an autoclave and heat it at 160 °C for 22 h, wash it with deionized water and ethanol, and freeze-dry it for 24 h to obtain flower-like nanospheres SnS 2 -NiS with a particle size D50 of 116 nm;

[0056] (5) Add 13 g of biochar and 1.4 g of flower-like nanospheres SnS 2 -NiS to deionized water, then add 0.7 g of sucrose, and react at 75 °C for 4 h. After centrifugation and drying, sinter it at 800 °C for 9 h under an Ar atmosphere to obtain the anode material SnS 2 -NiS@C for sodium-ion batteries.

[0057] Example 4

[0058] In this example, an anode material for sodium-ion batteries was prepared, and the specific process was as follows:

[0059] (1) Immerse 20 g of wood chips in 100 mL of 10% KOH solution by mass for 48 h, wash it with water until neutral, dry it and grind it to obtain a grinding material;

[0060] (2) Add the grinding material from step (1) to a muffle furnace, pyrolyze it at 750 °C for 4 h under a nitrogen atmosphere, wash it with deionized water until neutral, and dry it to obtain biochar with a particle size D50 of 10 μm;

[0061] (3) Add 1 mol of Na 2 SnO 3 and 1.5 mol of Ni(CH 3 COO) 2 to an aqueous deionized solution, then dropwise add ammonia solution, and slowly stir for 4 h. Finally, transfer the mixture to a 100 mL autoclave and heat it at 200 °C for 12 h, wash it with deionized water and ethanol, and then dry it at 60 °C for 12 h to obtain NiSn(OH) 6 nanospheres for collection;

[0062] (4) Dissolve 1 mol of NiSn(OH) prepared in step (3) 6 nanospheres in absolute ethanol, add 5 mol of thioacetamide under stirring conditions, ultrasonicate the mixture for 6 h, then transfer it to an autoclave and heat it at 200 °C for 24 h, wash it with deionized water and ethanol, and freeze-dry it for 24 h to obtain flower-like nanospheres SnS 2 -NiS with a particle size D50 of 108 nm;

[0063] (5) Add 20 g of biochar and 2 g of flower-like nanosphere SnS 2 -NiS to deionized water, then add 1 g of glucose, and react at 85 °C for 6 h. After centrifugation and drying, sinter at 900 °C for 12 h under an Ar atmosphere to obtain the anode material SnS 2 -NiS@C for sodium-ion batteries.

[0064] Comparative Example 1

[0065] A conventional biochar was prepared in this comparative example. The difference from Example 4 is that flower-like nanosphere SnS 2 -NiS is not prepared. The specific process is as follows:

[0066] (1) Add 20 g of wood chips to 100 mL of 10% KOH solution by mass, impregnate for 48 h, wash with water until neutral, dry and grind to obtain the abrasive;

[0067] (2) Add the abrasive from step (1) to a muffle furnace, pyrolyze at 750 °C for 4 h under a nitrogen atmosphere, then wash with deionized water until neutral, and dry to obtain biochar with a particle size D50 of 10 μm.

[0068] Comparative Example 2

[0069] An anode material for sodium-ion batteries was prepared in this comparative example. The difference from Example 4 is that thioacetamide is directly reacted with tin source and nickel source. The specific process is as follows:

[0070] (1) Add 1 mol of Na 2 SnO 3 and 1.5 mol of Ni(CH 3 COO) 2 to an aqueous deionized solution, then add 5 mol of thioacetamide under stirring conditions, ultrasonicate the resulting mixture for 6 h, then transfer it to an autoclave and heat at 200 °C for 24 h, wash with deionized water and ethanol, and freeze-dry for 24 h to obtain the sulfide SnS 2 -NiS;

[0071] (2) Add 20 g of biochar and 2 g of the sulfide SnS 2 -NiS to deionized water, then add 1 g of glucose, and react at 85 °C for 6 h. After centrifugation and drying, sinter at 900 °C for 12 h under an Ar atmosphere to obtain the anode material SnS 2 -NiS@C for sodium-ion batteries.

[0072] Test Example

[0073] The negative electrode materials of Examples 1-4 and the comparative examples were fabricated into negative electrode sheets of sodium-ion batteries and assembled into coin cells, which were tested at a current density of 100 mA g -1 and a voltage range of 0.4-2.6 V. The results are shown in Table 1.

[0074] Table 1

[0075]

[0076]

[0077] As can be seen from Table 1, in Comparative Example 1, conventional biochar was used as the negative electrode material, and its performance was much lower than that of the material containing nickel tin sulfide; in Comparative Example 2, thioacetamide was directly reacted with tin source and nickel source, and the synthesized sulfide had large particles, small specific surface area and poor cycle performance.

[0078] The embodiments of the present disclosure have been described in detail above with reference to the accompanying drawings. However, the present disclosure is not limited to the above embodiments, and various changes can be made without departing from the spirit of the present disclosure within the knowledge scope of those of ordinary skill in the art. In addition, the embodiments of the present disclosure and the features in the embodiments can be combined with each other without conflict.

Claims

1. A method for preparing a negative electrode material, It is characterized in that The following steps are involved: S1: Add ammonia solution to a mixed solution containing tin salt and nickel salt, and then heat to react to obtain NiSn(OH) 6 Nanospheres; S2: NiSn(OH) 6 The nanospheres are dispersed in a solvent, thioacetamide is added, and then heated to react to obtain flower-like nanospheres SnS 2 -NiS, NiSn(OH) 6 The molar ratio of the nanospheres to the thioacetamide is 1:(3-5); S3: The flower-like nanospheres SnS 2 -NiS, biochar and a binder are mixed in water, heated for reaction, and then solid-liquid separation is performed. The obtained solid is dried and then sintered in an inert atmosphere to obtain the negative electrode material.

2. The preparation method according to claim 1, It is characterized in that In step S1, the molar ratio of the tin salt to the nickel salt is 1:(1-1.5).

3. The preparation method according to claim 1, It is characterized in that In step S1, after the ammonia solution is added dropwise, the mixture is stirred for 1-4 hours and then heated for reaction.

4. The preparation method according to claim 1, It is characterized in that In step S1, the temperature of the heating reaction is 100-200°C; the time of the heating reaction is 6-12h.

5. The preparation method according to claim 1, It is characterized in that In step S1, after the heating reaction, the NiSn(OH) 6 The nanospheres were washed with water and ethanol and then dried at 60-70 °C for 6-12 h.

6. The preparation method according to claim 1, It is characterized in that In step S1, the tin salt is SnCl 4 、Na 2 SnO 3 or Sn(NO 3 ) 4 At least one of .

7. The preparation method according to claim 1, It is characterized in that In step S1, the nickel salt is Ni(CH 3 COO 2 , nickel sulfate or nickel chloride.

8. The preparation method according to claim 1, It is characterized in that In step S2, the temperature of the heating reaction is 150-200°C; the time of the heating reaction is 18-24h.

9. The preparation method according to claim 1, It is characterized in that In step S2, the flower-shaped nanospheres SnS 2 - The particle size D50 of NiS is 80-120 nm.

10. The preparation method according to claim 1, It is characterized in that In step S2, the solvent is at least one of anhydrous ethanol, propanol or pentanol.

11. The preparation method according to claim 1, It is characterized in that In step S2, after adding the thioacetamide, ultrasonication is performed for 2-6 hours, and then heating reaction is performed.

12. The preparation method according to claim 1, It is characterized in that In step S2, after the heating reaction, the flower-shaped nanospheres are washed with water and ethanol and freeze-dried for 22-24 hours.

13. The preparation method according to claim 1, It is characterized in that In step S3, the particle size D50 of the biochar is 6-15 μm.

14. The preparation method according to claim 1, It is characterized in that In step S3, the flower-shaped nanospheres SnS 2 -The mass ratio of NiS, biochar and binder is (1-2):(10-20):(0.5-1).

15. The preparation method according to claim 1, It is characterized in that In step S3, the sintering temperature is 700-900°C.

16. The preparation method according to claim 1, It is characterized in that In step S3, the binder is at least one of glucose or sucrose.

17. The preparation method according to claim 1, It is characterized in that In step S3, the heating reaction temperature is 55-85°C and the time is 2-6h.

18. The preparation method according to claim 1, It is characterized in that In step S3, the preparation method of the biochar is as follows: (1) soaking the biomass raw material in a KOH solution, and then washing, drying and grinding to obtain a grind; (2) pyrolyzing the grind under anaerobic conditions, and washing and drying to obtain the biochar.

19. The preparation method according to claim 18, It is characterized in that When preparing the biochar, in step (1), the biomass raw material is at least one of rice husks, wheat straws or sawdust.

20. Use of the negative electrode material obtained by the preparation method according to any one of claims 1 to 19 in sodium ion batteries.

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