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CN-121983532-A - Sodium ion battery flexible negative electrode material of double-carbon encapsulated selenium tin sulfide and preparation method thereof

CN121983532ACN 121983532 ACN121983532 ACN 121983532ACN-121983532-A

Abstract

The invention belongs to the technical field of battery materials, and particularly relates to a flexible negative electrode material of a sodium ion battery with double-carbon encapsulated selenium tin sulfide and a preparation method thereof. The selenium tin sulfide (SnSSe) in the material is encapsulated in a double-carbon layer consisting of hollow carbon spheres (HC) and flexible nitrogen-doped carbon Nanofibers (NCF). The preparation method of the material comprises the steps of firstly preparing hollow carbon spheres, then inducing generation SnSSe on the inner wall of the hollow carbon spheres through hydrothermal treatment to obtain SnSSe@HC, finally obtaining a flexible SnSSe@HC-electrostatic spinning nanofiber membrane through electrostatic spinning, and performing carbonization treatment to obtain the SnSSe@HC-NCF composite fiber membrane. The volume expansion of SnSSe in the sodium storage process can be more effectively limited through the special double-carbon layer structure, the dissolution of polysulfide and polyselenide is greatly limited, the cycling stability of the battery is improved, and the sodium storage stability of SnSSe is further improved.

Inventors

  • SONG YAN
  • LIN YAN
  • HUANG XIAOHUA
  • XIA XIAOMEI
  • DU PENG
  • WU JIANBO

Assignees

  • 台州学院

Dates

Publication Date
20260505
Application Date
20251212

Claims (10)

  1. 1. A flexible negative electrode material of a sodium ion battery of double-carbon encapsulated selenium tin sulfide is characterized in that the selenium tin sulfide is encapsulated in a double-carbon layer formed by hollow carbon spheres and flexible nitrogen-doped carbon nanofibers, snSSe are uniformly generated and distributed on the inner wall of the hollow carbon spheres to form SnSSe@HC, and the SnSSe@HC is completely wrapped in the flexible nitrogen-doped carbon nanofibers to form a flexible SnSSe@HC-NCF composite fiber film with a double-carbon layer structure.
  2. 2. The flexible negative electrode material of the sodium ion battery of the double-carbon encapsulated selenium tin sulfide according to claim 1, wherein the diameter of the hollow carbon sphere in the SnSSe@HC-NCF composite fiber film is 100-600nm.
  3. 3. The flexible negative electrode material of the sodium ion battery of the double-carbon encapsulated selenium tin sulfide according to claim 1, wherein the diameter of the flexible nitrogen-doped carbon nanofiber in the SnSSe@HC-NCF composite fiber film is 200-2000nm.
  4. 4. The flexible negative electrode material of the sodium ion battery of the double-carbon encapsulation selenium tin sulfide according to claim 1, wherein the content of SnSSe in the SnSSe@HC-NCF composite fiber film is 20-90 wt%.
  5. 5. A method for preparing the flexible negative electrode material of the sodium ion battery of the double-carbon encapsulation selenium tin sulfide as claimed in claims 1-4, which is characterized by comprising the following steps: Firstly, preparing hollow carbon spheres by using a template method; then, inducing a Sn source, an S source, a Se source and a reducing agent to generate SnSSe on the inner wall of the HC through hydrothermal treatment to obtain SnSSe@HC; Finally, dispersing the obtained SnSSe@HC in an N, N-dimethylformamide solution containing polyacrylonitrile and polyvinylpyrrolidone to obtain an electrostatic spinning precursor solution; carrying out electrostatic spinning on the electrostatic spinning precursor solution to obtain a flexible SnSSe@HC-electrostatic spinning nanofiber membrane; and carbonizing the obtained flexible SnSSe@HC-electrostatic spinning nanofiber membrane to obtain the SnSSe@HC-NCF composite fiber membrane.
  6. 6. The preparation method of the flexible negative electrode material of the sodium ion battery with the double-carbon encapsulated selenium tin sulfide as claimed in claim 5, which is characterized by comprising the following specific steps: (1) Preparing hollow carbon spheres: firstly, resorcinol, formaldehyde, ammonia water and ethyl orthosilicate are added in a solvent system of ethanol and water, and stirring is carried out at room temperature, thus obtaining phenolic resin/silicon dioxide composite microspheres; Then, calcining the obtained phenolic resin/silicon dioxide composite microspheres in a nitrogen atmosphere to obtain carbon/silicon dioxide microspheres; Finally, etching the carbon/silicon dioxide microspheres by adopting a sodium hydroxide solution under a heating condition to remove silicon dioxide, thereby obtaining hollow carbon spheres; (2) Preparation of snsse@hc: Dispersing the hollow carbon spheres obtained in the step (1) in an aqueous solution composed of a Sn source, an S source, a Se source and a reducing agent, and performing hydrothermal treatment for 8-12 hours at 160-200 ℃ to prepare SnSSe@HC; (3) Preparing a SnSSe@HC-NCF composite fiber membrane: Firstly, dispersing SnSSe@HC obtained in the step (2) in N, N-Dimethylformamide (DMF) solution containing a mixed polymer consisting of polyacrylonitrile and polyvinylpyrrolidone, and carrying out ultrasonic and uniform stirring to obtain an electrostatic spinning precursor solution; then, carrying out electrostatic spinning on the obtained electrostatic spinning solution to obtain a flexible SnSSe@HC-electrostatic spinning nanofiber membrane; and finally, carbonizing the obtained flexible SnSSe@HC-electrostatic spinning nanofiber membrane under a nitrogen protective atmosphere to obtain the SnSSe@HC-NCF composite fiber membrane.
  7. 7. The preparation method of the flexible negative electrode material of the double-carbon encapsulated selenium tin sulfide sodium ion battery, which is characterized in that the Sn source is at least one of sodium stannate, tin chloride or stannous chloride, the S source is at least one of thiourea, sodium sulfide or thioacetamide, the Se source is at least one of selenium oxide, sodium selenate or selenium powder, and the reducing agent is sodium borohydride or hydrazine hydrate.
  8. 8. The preparation method of the flexible negative electrode material of the sodium ion battery of the double-carbon packaged selenium tin sulfide, which is characterized in that in the step (1), the mass ratio of formaldehyde to resorcinol to ammonia water to ethyl orthosilicate to ethanol is 1:2 (5-20): (40-70): (20-40): (300-400); The stirring time is 12-24h, the calcining treatment temperature is 600-900 ℃, the calcining treatment time is 2-4h, the heating rate of the calcining treatment is 5 ℃ per minute, the concentration of the sodium hydroxide solution is 1-4mol/L, and the etching temperature is 60-100 ℃.
  9. 9. The preparation method of the flexible negative electrode material of the sodium ion battery with the double-carbon encapsulated selenium tin sulfide, which is disclosed in claim 6, is characterized in that the mass ratio of the hollow carbon sphere to the Sn source to the S source to the Se source to the reducing agent to the water in the step (2) is 1 (5-10), 1-2-4, 5-10 and 500-600.
  10. 10. The preparation method of the flexible negative electrode material of the sodium ion battery of the double-carbon encapsulated selenium tin sulfide, which is characterized in that the mass ratio of polyacrylonitrile to polyvinylpyrrolidone in the mixed polymer in the step (3) is 1:1, wherein the weight average molecular weight of the polyacrylonitrile is 15 ten thousand, and the weight average molecular weight of the polyvinylpyrrolidone is 130 ten thousand; The mass ratio of the SnSSe@HC to the mixed polymer is (0.1-1): 1, and the concentration of the mixed polymer solution in N, N-dimethylformamide is 10% -30% (w/v); The voltage of the electrostatic spinning is 15-30kV, the spinning distance is 10-20cm, and the flow rate of the electrostatic spinning precursor solution is 0.1-10mL/h; The carbonization temperature is 600-900 o ℃, the carbonization time is 2-4h, and the heating rate of the carbonization is 1 ℃ per minute.

Description

Sodium ion battery flexible negative electrode material of double-carbon encapsulated selenium tin sulfide and preparation method thereof Technical Field The invention belongs to the technical field of battery materials, and particularly relates to a flexible negative electrode material of a sodium ion battery with double-carbon encapsulated selenium tin sulfide and a preparation method thereof. Background The mechanism of the sodium ion battery is similar to that of the lithium ion battery, and the sodium-based battery has high earth abundance and low cost, so that the sodium ion battery has great application potential in the future large-scale energy storage field, and is a competitive novel energy storage system. However, since the ionic radius of sodium ions is much larger than that of lithium ions, graphite, which is a negative electrode material of a conventional lithium ion battery, cannot be directly used as a negative electrode material of a sodium ion battery. Tin disulfide (SnS 2) has the potential of becoming a negative electrode material of a sodium ion battery due to the high theoretical specific capacity (1136 mAh.g -1), low cost and large interlayer spacing. However, the lower inherent conductivity of the SnS 2 and the remarkable volume expansion (about 324%) in the sodium storage process lead to poor rate performance and cycle stability, which greatly influence the practical application of the SnS 2 in sodium ion batteries. In order to improve the stability and the conductivity of SnS 2 in the sodium storage process, the prior study proves that the heterogeneous atom Se is used for replacing sulfur in SnS 2 to prepare a tin selenide sulfide (SnSSe) composite material, and the introduction of the heterogeneous atom Se can improve the conductivity of SnS 2, enlarge the interlayer spacing and improve the rate capability of the composite material. However, as with SnS 2, snSSe still suffers from the problems of large volume expansion and dissolution of polysulfides and polyselenide during circulation, resulting in poor long-cycle stability of SnSSe. To solve the above problems, it has been found that SnSSe can be encapsulated inside a carbon material that can limit the volume expansion of SnSSe while reducing the dissolution of polysulfides and polyselenide. However, the carbon layers currently prepared in the prior art are generally porous or open structures and have very limited effectiveness in limiting the volume expansion of SnSSe and reducing the dissolution of polysulfides and polyselenide. Disclosure of Invention The invention aims to provide the flexible negative electrode material of the double-carbon encapsulated sodium tin selenide sulfide ion battery and the preparation method thereof, aiming at the defects, the volume expansion of SnSSe in the sodium storage process can be more effectively limited through a special double-carbon layer structure, the dissolution of polysulfide and polyselenide is greatly limited, the cycling stability of the battery is improved, and the sodium storage stability of SnSSe is further improved. The technical scheme of the invention is as follows: A flexible negative electrode material of a sodium ion battery of double-carbon encapsulation selenium tin sulfide is characterized in that SnSSe is encapsulated in a double-carbon layer formed by a hollow carbon sphere (HC) and flexible nitrogen-doped carbon Nanofiber (NCF), wherein SnSSe is uniformly generated and distributed on the inner wall of the hollow carbon sphere to form SnSSe@HC, and the SnSSe@HC is completely wrapped in the flexible nitrogen-doped carbon nanofiber to form a flexible SnSSe@HC-NCF composite fiber membrane with a double-carbon layer structure. The special structure of the double-carbon package can effectively improve the volume expansion of SnSSe when being used as a negative electrode material of a sodium ion battery and the dissolution problem of polysulfide/selenide. Further, in the SnSSe@HC-NCF composite fiber membrane, the diameter of the hollow carbon sphere is 100-600nm. Further, in the SnSSe@HC-NCF composite fiber film, the diameter of the flexible nitrogen doped carbon nanofiber is 200-2000nm. Further, the content of SnSSe in the SnSSe@HC-NCF composite fiber film is 20-90 wt%. The preparation method of the sodium ion battery flexible negative electrode material of the double-carbon encapsulated selenium tin sulfide comprises the following steps: First, hollow carbon spheres are prepared using a template method. Then, based on oxygen-containing functional groups rich in the inner surface of the hollow carbon sphere, inducing a Sn source, an S source, a Se source and a reducing agent to generate SnSSe on the inner wall of HC through hydrothermal treatment, so as to obtain SnSSe@HC. Finally, dispersing the obtained SnSSe@HC in an N, N-dimethylformamide solution containing polyacrylonitrile and polyvinylpyrrolidone to obtain an electrostatic spinning precursor solution, and carry