A gallium sulfide / carbon composite negative electrode material and its preparation method and application

Abstract

This invention belongs to the technical field of sodium-ion energy storage devices, specifically relating to a gallium sulfide / carbon composite anode material, its preparation method, and its application. A Ga2S3 / C composite anode material is synthesized through solvothermal synthesis of a precursor template followed by in-situ high-temperature sulfurization and sintering. This material utilizes nanostructure design and carbon coating to shorten ion transport distances and enhance diffusion kinetics, mitigating volume expansion during energy storage and improving material stability. As a sodium-ion battery anode material, it exhibits excellent rate capability and good cycling stability.

Description

Technical Field

[0001] The present invention belongs to the technical field of sodium ion energy storage devices, and specifically relates to a gallium sulfide / carbon composite negative electrode material and a preparation method and application thereof. Background Art

[0002] The information disclosed in this background technology section is only intended to enhance understanding of the overall background of the invention and should not necessarily be regarded as an admission or any form of suggestion that the information constitutes the prior art already known to those skilled in the art.

[0003] In recent years, lithium-ion batteries (LIBs) have played an important role in portable electronic devices, hybrid electric vehicles, and emerging smart grids due to their high power density, good cyclability, and environmental friendliness. However, conventional graphite anode materials with limited theoretical capacity (372 mAh g -1 ) and traditional LiMO2 cathode materials have reached their practical upper limit and cannot meet the requirements of high energy density and high power density. Sodium ion batteries (SIBs) have a rocking chair mechanism similar to LIBs and have become a potential candidate for new energy storage systems. Although Na has a heavier atomic mass than Li (23 vs. 6.9 g mol -1 ), larger ion size (1.02 pairs ) and a higher standard electrode potential (-2.71 vs. -3.02 V), but the crustal abundance, low cost, and stable supply chain of Na are conducive to the research and development of electrode materials and the large-scale production of batteries. In addition, low-cost aluminum foil can be used instead of expensive copper foil as the negative electrode current collector of SIBs, which can reduce the production cost of batteries by 8% and accelerate the practical application of SIBs.

[0004] To achieve high energy density and power density, developing electrode materials with both high capacity and excellent rate performance is a prerequisite. Among the numerous anode materials, alloys and conversion materials have attracted widespread attention due to their high specific energy. However, these materials are accompanied by significant volume expansion during energy storage, resulting in high initial irreversible losses, rapid capacity decay, and poor rate performance. Poor electronic conductivity in some conversion materials also limits their widespread application. Previous studies have demonstrated that nanostructuring or making electrode materials porous can shorten the sodium ion diffusion distance, increase the contact area between the electrode material and the electrolyte, and improve sodium ion transport kinetics. The introduction of carbon materials facilitates material dispersion, provides an elastic substrate, mitigates volume expansion, and enhances electronic conductivity. Furthermore, MOFs have been shown to be effective templates for preparing anode materials with unique, ordered nanostructures. However, these strategies often require a combination to achieve optimal results. Therefore, the design and production of stable anode materials with high energy density and long cycle life suitable for SIBs is urgently needed.

[0005] Gallium sulfide material has a high theoretical capacity (1137 mAh g -1 ) and environmental friendliness, and can store sodium ions through electrochemical conversion-alloying mechanism, but due to its poor conductivity, the large volume expansion during repeated sodium deintercalation / embedding leads to poor electrochemical properties (cycle, rate) of the material. Summary of the Invention

[0006] In response to the above-mentioned problems, the purpose of the present invention is to provide a gallium sulfide / carbon composite negative electrode material and its preparation method and application. The present invention realizes the composite of materials by solvent thermal synthesis of precursor templates and in-situ high-temperature sulfurization sintering. Nanostructure design and carbon coating strategies are used to shorten the ion transmission distance and improve the diffusion dynamics, while alleviating the volume expansion during the energy storage process and improving the stability of the material. In addition, the Ga2S3 / C composite negative electrode material prepared by the present invention can flexibly control the length, width and surface morphology of the material by designing the precursor template and adjusting the sintering time.

[0007] Specifically, the present invention provides the following technical solutions:

[0008] In a first aspect of the present invention, a Ga2S3 / C composite negative electrode material for a sodium ion battery is provided, wherein the Ga2S3 / C composite negative electrode material comprises Ga2S3 nanowires and a carbon matrix distributed inside and on the surface of the Ga2S3 nanowires;

[0009] The carbon matrix is ​​derived from terephthalic acid;

[0010] The Ga2S3 has an α-type monoclinic structure and belongs to the Cc(9) space group. The lattice constant is

[0011] A second aspect of the present invention provides a method for preparing a Ga2S3 / C composite negative electrode material for a sodium ion battery, comprising the following preparation steps:

[0012] S1. Gallium salt is dissolved in an organic solvent to form solution A;

[0013] S2, mixing terephthalic acid and 1,2-benzisothiazol-3-one and dissolving them in an organic solvent to form a solution B;

[0014] S3, mixing solution A and solution B, performing a solvothermal reaction, and preparing a MIL-68-Ga precursor;

[0015] S4. Sinter the MIL-68-Ga precursor with a sulfur source to obtain a Ga2S3 / C composite negative electrode material.

[0016] Preferably, in step S1 and step S2, the organic solvent is N,N-dimethylformamide.

[0017] Preferably, in step S1, the gallium salt is a gallium cation or a compound of gallium ions, specifically selected from Ga(NO3)3, Ga(NO3)3·xH2O, Ga2(SO4)3, Ga(SO3)3·xH2O, C 15 H 21 One or more of O6Ga (gallium acetylacetonate), GaCl3, GaI3, and Ga2Cl4.

[0018] Preferably, the molar ratio of the terephthalic acid to the gallium salt is 1 to 7:1; and the molar ratio of the terephthalic acid to 1,2-benzisothiazol-3-one is 0.5 to 7:1.

[0019] More preferably, the molar ratio of the terephthalic acid to the gallium salt is 3:1; and the molar ratio of the terephthalic acid to 1,2-benzisothiazol-3-one is 0.9:1.

[0020] Preferably, in step S2, the 1,2-benzisothiazol-3-one is used as a regulator, which can directly affect the morphology of the MIL-68-Ga precursor and indirectly affect the morphology and properties of the Ga2S3 / C nanowires.

[0021] Preferably, in step S3, the solvent thermal reaction temperature is 100° C. to 240° C., and the reaction time is 6 h to 24 h.

[0022] More preferably, the solvent thermal reaction temperature is 120° C. and the reaction time is 10 h.

[0023] Preferably, in step S3, the product after the solvothermal reaction is washed with N,N-dimethylformamide and deionized water for 3 to 5 times, and then freeze-dried to obtain a MIL-68-Ga precursor.

[0024] Preferably, in step S4, the sulfur source is a substance containing sulfur element, specifically selected from one or more of thiourea, thioacetamide, and sulfur powder.

[0025] Preferably, in step S4, the mass ratio of the MIL-68-Ga precursor to the sulfur source is 1:1 to 1:5.

[0026] Further preferably, the mass ratio of the MIL-68-Ga precursor to the sulfur source is 1:5.

[0027] Preferably, in step S4, the MIL-68-Ga precursor and the sulfur source are placed on both sides of the crucible, respectively, with the sulfur source close to the gas inlet end and the MIL-68-Ga precursor close to the gas outlet end.

[0028] Preferably, in step S4, the sintering treatment is performed by heating to 600° C. to 1000° C. at a heating rate of 1 to 5° C. / min, and the holding time is 0.5 to 5 h.

[0029] More preferably, the sintering treatment is performed by heating to 800° C. at a heating rate of 1-5° C. / min and holding the temperature for 1 hour.

[0030] Preferably, in step S4, the sintering treatment is performed in an inert atmosphere, and the inert atmosphere is one or a combination of hydrogen, nitrogen, and argon.

[0031] The third aspect of the present invention provides the use of the Ga2S3 / C composite negative electrode material described in the first aspect in the preparation of a sodium ion energy storage device.

[0032] A fourth aspect of the present invention provides a battery negative electrode, comprising the Ga2S3 / C composite negative electrode material described in the first aspect as an active material;

[0033] Preferably, the battery negative electrode further includes a conductive material and a binder.

[0034] More preferably, the conductive material is acetylene black or Super P.

[0035] Preferably, the binder is polyvinylidene fluoride (PVDF) or sodium carboxymethyl cellulose (CMC).

[0036] Preferably, the mass ratio of the active material, the conductive material and the binder is 6-8:1.6-2.4:0.6-1.4.

[0037] The fifth aspect of the present invention provides a sodium ion battery or capacitor, comprising the battery negative electrode described in the fourth aspect.

[0038] Preferably, the sodium ion battery or capacitor further comprises a positive electrode, a separator, and an electrolyte.

[0039] Further preferably, the electrolyte is prepared by dissolving 1M NaPF6 in ethylene glycol dimethyl ether (DME).

[0040] One or more embodiments of the present invention have at least the following beneficial effects:

[0041] (1) The present invention prepares Ga2S3 / C composite materials with different crystallinity through in-situ solid-phase sulfurization and sintering treatment, which can effectively improve volume expansion and nanoparticle agglomeration, while ensuring that the structure of the original precursor does not collapse or change. It can not only improve the material's conductivity but also shorten the ion diffusion path. The synthesized Ga2S3 / C composite material can also be used as a negative electrode material for sodium-ion batteries, improving the sodium ion transport kinetics.

[0042] (2) The present invention can prepare Ga2S3 / C composite materials with different crystallinity by controlling the heating rate and reaction time during the sulfurization process. In particular, the materials with different crystallinity have no significant differences in structure and crystal form.

[0043] (3) The present invention uses MOF-Ga derivatives as precursor templates to prepare specific nanowire materials, which can provide a stable framework configuration with a large specific surface area, providing an experimental basis for the subsequent development of Ga2S3 / C composite materials in the field of sodium ion energy storage. The designed nanowire structure is conducive to alleviating the volume expansion during the charge and discharge process and improving the electrochemical performance.

[0044] (4) The Ga2S3 / C composite material prepared by the present invention has excellent rate performance and good cycle stability as a negative electrode material for sodium ion batteries.

[0045] (5) The preparation method of the present invention is simple and efficient, easy to synthesize, and the product is easily obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0047] Figure 1 This is a SEM image of the MIL-68-Ga precursor prepared in Example 1 of the present invention;

[0048] Figure 2 This is an SEM image of the Ga2S3 / C composite negative electrode material prepared in Example 1 of the present invention;

[0049] Figure 3 XRD patterns of Ga2S3 / C composite negative electrode materials prepared under different temperature conditions in the present invention;

[0050] Figure 4 The Ga2S3 / C composite negative electrode material prepared in Example 1 of the present invention is used as a negative electrode material for sodium ion batteries in 2Ag -1 Cyclic performance test under current density;

[0051] Figure 5 The Ga2S3 / C composite negative electrode material prepared in Example 1 of the present invention is used as a negative electrode material for sodium ion batteries at 5Ag -1 Cyclic performance test under current density;

[0052] Figure 6 This is a rate performance test diagram of the Ga2S3 / C composite negative electrode material prepared in Example 1 of the present invention as a negative electrode material for sodium ion batteries;

[0053] Figure 7 This is a SEM image of the MIL-68-Ga precursor prepared in Comparative Example 1 of the present invention;

[0054] Figure 8 This is the SEM image of the MIL-68-Ga precursor prepared in Comparative Example 2 of the present invention. DETAILED DESCRIPTION

[0055] It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those skilled in the art to which the present invention belongs.

[0056] The present invention will be further described in detail below with reference to specific embodiments. It should be noted that the specific embodiments are intended to explain the present invention rather than to limit it.

[0057] Example 1 : This embodiment provides a method for preparing Ga2S3 / C composite negative electrode material for sodium ion batteries.

[0058] S1. Dissolve 0.5 g of gallium nitrate hydrate in 25 mL of N,N-dimethylformamide to form a transparent solution A.

[0059] S2. Dissolve 1 g of terephthalic acid and 1 g of 1,2-benzisothiazol-3-one in 25 mL of N,N-dimethylformamide to form a transparent solution B.

[0060] S3. Slowly pour solution B into solution A to form a mixed solution, magnetically stir for 30 minutes, transfer the mixed solution to a high-pressure reactor, place it in a drying oven at 120°C for 10 hours, wash it with DMF and deionized water 3-5 times, and freeze-dry to prepare the MIL-68-Ga precursor.

[0061] S4. Place the MIL-68-Ga precursor and sulfur powder at a mass ratio of 1:5 on both sides of a porcelain boat, and sinter them at 800°C for 1 hour under an argon atmosphere to obtain a Ga2S3 / C composite negative electrode material.

[0062] The Ga2S3 / C particles of the Ga2S3 / C composite negative electrode material are α-type monoclinic crystals, belonging to the Cc(9) space group, and the lattice constant

[0063] like Figure 1 This is a scanning electron microscope image of the MIL-68-Ga precursor, which has good dispersion and uniform size. It is a linear material with a width of about 300-500nm and a length of about 6-8μm. Figure 2 and Figure 3 Shown are scanning electron microscope and transmission electron microscope images of metal sulfide / C nanowires prepared using MIL-68-Ga as a template.

[0064] from Figure 2 It can be seen that the structure of the prepared material remains relatively intact after high-temperature treatment, and no collapse occurs;

[0065] from Figure 3 It can be seen that the X-ray diffraction pattern of the prepared Ga2S3 / C composite negative electrode material shows three sharp diffraction peaks at 27.808°, 27.741° and 29.661° (700-800°C is a steamed bun-shaped bulge, 900-1000°C is a sharp peak), which correspond to the metal sulfide (020), (311) and (002) planes, respectively, and are typical Ga2S3 characteristic peaks (JCPDS, No. 76-0752).

[0066] Example 2 : This example provides a cycling performance test of the Ga2S3 / C composite negative electrode material prepared in Example 1 as a negative electrode material for sodium ion batteries at different current densities.

[0067] A Ga2S3 / C composite anode material, acetylene black, and CMC were mixed in a mass ratio of 8:1:1, coated onto copper foil, and vacuum-dried at 80°C for 10 hours. A CR2032 coin cell was assembled in an argon-protected glove box using sodium metal as the counter electrode, a glass fiber membrane (Whatman GF / C) as the separator, and 1M NaPF6 dissolved in ethylene glycol dimethyl ether (DME) as the electrolyte. Electrochemical testing was performed after 12 hours of rest. The test voltage range was 0.01 to 3 V.

[0068] like Figure 4 As shown in the figure, the sodium battery negative electrode cycle test was carried out at a constant temperature of 30°C and a current density of 2A / g. The battery can still release a capacity of 580mAh / g after 1000 cycles, and the capacity after the cycle is almost no decay, showing good cycle performance;

[0069] like Figure 5 As shown in the figure, the sodium battery negative electrode cycle test was carried out at a constant temperature of 30°C and a current density of 5A / g. The battery can still release a capacity of 562mAh / g after 2000 cycles at 569.8mAh / g, with a capacity retention rate of 98.63%, showing excellent long-term cycle performance.

[0070] Example 3 : This example provides a rate performance test diagram of the Ga2S3 / C composite negative electrode material prepared in Example 1 as a negative electrode material for sodium ion batteries.

[0071] like Figure 6 As shown, the rate performance of the CR2032 button battery assembled in Example 2 was tested at different current densities of 100mA / g, 200mA / g, 500mA / g, 800mA / g, 1000mA / g, 2000mA / g, 5000mA / g, 8000mA / g, 10000mA / g and 15000mA / g in a constant temperature environment of 30°C.

[0072] The material has a specific capacity of 630 mAh / g at 100 mA / g and a capacity of 442 mAh / g at 15,000 mA / g, demonstrating superior rate performance. Testing has shown that the Ga2S3 / C composite anode material has excellent structural stability.

[0073] Example 4

[0074] The difference from Example 1 is that the mass ratio of the MIL-68-Ga precursor to sulfur powder in step S4 is 1:2.

[0075] Example 5

[0076] The difference from Example 1 is that the mass ratio of the MIL-68-Ga precursor to sulfur powder in step S4 is 1:4.

[0077] Example 6

[0078] The difference from Example 1 is that the sulfur source in step S4 is thioacetamide.

[0079] Example 7

[0080] The difference from Example 1 is that the sulfur source in step S4 is thiourea.

[0081] Example 8

[0082] The difference from Example 1 is that the holding temperature in step S4 is 700°C.

[0083] Example 9

[0084] The difference from Example 1 is that the holding temperature in step S4 is 900°C.

[0085] Example 10

[0086] The difference from Example 1 is that the holding temperature in step S4 is 1000°C.

[0087] Example 11

[0088] The difference from Example 1 is that the holding time in step S4 is 3 hours.

[0089] Comparative Example 1

[0090] The difference from Example 1 is that the mass of 1,2-benzisothiazol-3-one in step S2 is 0 g.

[0091] like Figure 7 The morphology of the synthesized material shows that when 1,2-benzisothiazol-3-one is not added, the MOF material appears to be agglomerated and adhered, and is in the form of lines with very uneven sizes, on which some nanoparticles and ungrown short lines are attached.

[0092] Comparative Example 2

[0093] The difference from Example 1 is that the mass of 1,2-benzisothiazol-3-one in step S2 is 0.5 g.

[0094] like Figure 8As for the morphology of the synthesized material, when the amount of 1,2-benzisothiazol-3-one is less, the agglomeration phenomenon of the MOF material is improved, the surface is basically smooth and free of particles, and a linear structure is more clearly observed, but the grown wires are still uneven.

[0095] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A Ga2S3 / C composite negative electrode material for sodium ion batteries, characterized in that: The Ga2S3 / C composite negative electrode material comprises Ga2S3 nanowires and a carbon matrix distributed inside and on the surface of the Ga2S3 nanowires; The carbon matrix is ​​derived from terephthalic acid; The Ga2S3 has an α-type monoclinic structure and belongs to the Cc (9) space group, with lattice constants of a=11.140 Å ± 0.01 Å, b=6.411 Å ± 0.01 Å, and c=7.038 Å ± 0.01 Å; The preparation method of the Ga2S3 / C composite negative electrode material for sodium ion batteries comprises the following preparation steps: S1. Gallium salt hydrate is dissolved in an organic solvent to form solution A; S2, mixing terephthalic acid and 1,2-benzisothiazol-3-one and dissolving them in an organic solvent to form a solution B; S3, mixing solution A and solution B, performing a solvothermal reaction, and preparing a MIL-68-Ga precursor; S4, sintering the MIL-68-Ga precursor with a sulfur source to obtain a Ga2S3 / C composite negative electrode material; In step S1 and step S2, the organic solvent is N,N-dimethylformamide; The molar ratio of the terephthalic acid to the gallium salt hydrate is 3:1; the molar ratio of the terephthalic acid to 1,2-benzisothiazol-3-one is 0.9:

1.

2. A method for preparing the Ga2S3 / C composite negative electrode material for sodium ion batteries according to claim 1, characterized in that: The method comprises the following preparation steps: S1. Gallium salt hydrate is dissolved in an organic solvent to form solution A; S2, mixing terephthalic acid and 1,2-benzisothiazol-3-one and dissolving them in an organic solvent to form a solution B; S3, mixing solution A and solution B, performing a solvothermal reaction, and preparing a MIL-68-Ga precursor; S4, sintering the MIL-68-Ga precursor with a sulfur source to obtain a Ga2S3 / C composite negative electrode material; In step S1 and step S2, the organic solvent is N,N-dimethylformamide.

3. The preparation method according to claim 2, wherein In step S1, the gallium salt hydrate is a compound of gallium cations or gallium ions, specifically selected from Ga(NO3)3, Ga2(SO4)3, C 15 H 21 One or more of O6Ga, GaCl3, GaI3, and Ga2Cl4; In step S4, the sulfur source is a substance containing sulfur element, specifically selected from one or more of thiourea, thioacetamide, and sulfur powder.

4. The preparation method according to claim 2, wherein In step S3, the solvent thermal reaction temperature is 100° C. to 240° C., and the reaction time is 6 h to 24 h.

5. The preparation method according to claim 4, wherein The solvent thermal reaction temperature is 120° C. and the reaction time is 10 h.

6. The preparation method according to claim 2, wherein In step S3, the product after the solvothermal reaction is washed with N,N-dimethylformamide and deionized water for 3-5 times, and then freeze-dried to obtain a MIL-68-Ga precursor.

7. The preparation method according to claim 2, wherein In step S4, the mass ratio of the MIL-68-Ga precursor to the sulfur source is 1:1 to 1:5; the sintering treatment is performed by heating to 600° C. to 1000° C. at a heating rate of 1 to 5° C. / min, and holding the temperature for 0.5 to 5 h.

8. The preparation method according to claim 7, wherein The mass ratio of the MIL-68-Ga precursor to the sulfur source is 1:5; the sintering process is performed by heating to 800° C. at a heating rate of 1-5° C. / min and holding the temperature for 1 h.

9. Use of the Ga2S3 / C composite negative electrode material according to claim 1 in the preparation of a sodium ion battery.

10. A battery negative electrode, characterized in that: The Ga2S3 / C composite negative electrode material according to claim 1 is included as an active material.

11. The battery negative electrode according to claim 10, wherein: The battery negative electrode further includes a conductive material and a binder.

12. The battery negative electrode according to claim 11, wherein: The conductive material is acetylene black or Super P; the binder is polyvinylidene fluoride or sodium carboxymethyl cellulose.

13. The battery negative electrode according to claim 10, wherein: The mass ratio of the active material, the conductive material and the binder is 6-8:1.6-2.4:0.6-1.

4.

14. A sodium ion battery, characterized in that: The battery negative electrode comprises the battery negative electrode according to any one of claims 10 to 13.

15. The sodium ion battery according to claim 14, wherein The sodium ion battery further includes a positive electrode, a separator, and an electrolyte.

16. The sodium ion battery according to claim 15, wherein The electrolyte is prepared by dissolving 1 M NaPF6 in ethylene glycol dimethyl ether.

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