High-performance sodium ion battery negative electrode ZnS / CoS-C composite material and preparation method thereof

Abstract

The invention discloses a high-performance sodium ion battery negative electrode ZnS / CoS (at) C composite material and a preparation method thereof, the material preparation method has the characteristics of definite control parameter, easy purity control, simple operation, good process repeatability and the like, and the prepared sodium ion secondary battery negative electrode material has excellent sodium ion intercalation and deintercalation capability and can be used for preparing a sodium ion secondary battery negative electrode material. The specific capacity, the cycling stability, the coulombic efficiency and the rate capability of the sodium ion secondary battery can be effectively improved, the requirements of different conditions can be met, and the application prospect is wide.

Description

Technical Field

[0001] This invention belongs to the field of inorganic nanomaterials in sodium-ion secondary battery application technology, specifically relating to a high-performance sodium-ion battery negative electrode ZnS / CoS@C composite material and its preparation method. Background Technology Lithium-ion batteries, as a new energy storage technology, have wide applications in new energy vehicles, data center power supply, and other fields. However, due to the low content and uneven distribution of lithium in the Earth's crust, there is an urgent need to develop new electrochemical energy sources. To accelerate the development of the new energy industry. In recent years, sodium has abundant reserves and low cost, and sodium-ion batteries have shown good application prospects in electrochemical energy storage systems. However, Na... + The large ionic radius of sodium ions (1.02 Å) inevitably leads to slow ion kinetics in the electrode, resulting in poor rate performance. Furthermore, the significant volume expansion of the electrode material during charge and discharge causes unsatisfactory cycle stability. Therefore, exploring electrode materials with rapid sodium ion / electron transfer and excellent structural stability is urgently needed.

[0002] Metal sulfides, due to their abundant active centers, suitable electronic band structure, and excellent mechanical properties, have broad application prospects in the field of SIBs. However, Na... + The severe volume expansion caused by insertion and extraction leads to poor cycling stability and rate. To address the poor cycling stability of ZnS electrode materials, the preparation of metal sulfide heterostructures by deriving metal-organic frameworks (MOFs) is a very effective method. Summary of the Invention The technical problem this invention aims to solve is: to address the issue of sodium storage in metal sulfides, a one-step sulfidation treatment of a zinc / cobalt bimetallic organic framework was performed to prepare ZnS / CoS@C nanorods. The built-in electric field formed at the heterogeneous phase interface can accelerate the synthesis of Na+. + And the electron transport rate. Furthermore, the uniform encapsulation of ZnS / CoS by MOF-derived amorphous carbon accelerates external charge transfer, promotes the volume expansion of ZnS / CoS, and improves the stability of the structure.

[0003] The technical problem to be solved by this invention is achieved by the following technical solution: The first objective of this invention is to provide a method for preparing a high-performance anode material for sodium-ion batteries, which obtains the anode material for sodium-ion batteries through a solvothermal method and a heat treatment process, including the following steps: S1: Add zinc salt, cobalt salt and dimethylimidazole together to 10 mL of glycerol solution; S2: The above mixed solution is dispersed evenly by continuous stirring to obtain a uniformly dispersed solution; S3: Transfer the dispersion to a high-pressure reactor for solvothermal reaction to obtain purple precursor powder; S4: The purple precursor powder is physically mixed with sublimed sulfur powder and placed in a tube furnace for calcination in an argon atmosphere to obtain ZnS / CoS@C nanorods; Optionally, in step S1, the zinc salt is at least one of zinc chloride, zinc nitrate, and zinc sulfate.

[0004] Optionally, in step S1, the cobalt salt is one or more of cobalt chloride, cobalt nitrate, and cobalt sulfate.

[0005] Optionally, in step S2, the mixing time of the mixed solution is 12h to 24h.

[0006] Optionally, in step S3, the solvothermal reaction temperature is 150–180 °C.

[0007] Optionally, in step S4, the purple precursor powder and sublimed sulfur powder are physically mixed by grinding or ball milling.

[0008] Optionally, in step S4, the sintering temperature is 500–600°C and the time is 1–3 h.

[0009] A second objective of this invention is to provide a negative electrode material for sodium-ion batteries prepared according to the aforementioned preparation method.

[0010] The beneficial effects of this invention are: This invention provides a method for preparing a negative electrode material for sodium-ion batteries. This preparation method has the characteristics of simple operation, good process repeatability, clear control parameters, and stable product quality. Furthermore, the negative electrode material prepared by this method has good cycle stability and rate performance. Attached Figure Description

[0011] Figure 1 The morphological photograph provided in Embodiment 1 of the present invention; Figure 2 The charge-discharge curve provided in Embodiment 1 of the present invention; Figure 3 The morphological photograph provided for Comparative Embodiment 1 of the present invention; Figure 4 The charge-discharge curves provided in Comparative Example 1 of the present invention; Figure 5 Example 1 of the present invention and Comparative Example 1 are compared in 1 A g -1 Under normal cyclic performance; Figure 6 Rate cycling performance of Example 1 and Comparative Example 1 of the present invention Detailed Implementation

[0012] The following will describe the concept and technical effects of the present invention clearly and completely with reference to embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are intended to explain the present invention and should not be construed as limiting the present invention, nor are they all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention.

[0013] Example 1 The high-performance sodium-ion battery anode ZnS / CoS@C composite material and its preparation method in this embodiment include the following steps: S1: Disperse 61.2 mg ZnCl2, 11.9 mg CoCl2 and 124.8 mg dimethylimidazole in 10 mL glycerol and stir for 12 hours to obtain a uniform dispersion.

[0014] S2: Transfer the dispersion to a high-pressure reactor and react at 160 °C for 3 hours to obtain a purple precursor powder.

[0015] S3: The precursor and sublimated S powder were physically mixed at a mass ratio of 1:3, and heated at a rate of 5℃ / min under an Ar atmosphere. -1 Calcination at 600℃ for 3 hours yielded ZnS / CoS@C; Example 2 The high-performance sodium-ion battery anode ZnS / CoS@C composite material and its preparation method in this embodiment include the following steps: S1: Disperse 61.2 mg ZnCl2, 11.9 mg CoCl2 and 124.8 mg dimethylimidazole in 10 mL glycerol and stir for 12 hours to obtain a uniform dispersion.

[0016] S2: Transfer the dispersion to a high-pressure reactor and react at 180 °C for 3 hours to obtain a purple precursor powder.

[0017] S3: The precursor and sublimated S powder were physically mixed at a mass ratio of 1:3, and heated at a rate of 5℃ / min under an Ar atmosphere. -1 Calcination at 600℃ for 3 hours yielded ZnS / CoS@C; Comparative Example 1 S1: Disperse 68 mg ZnCl2 and 124.8 mg dimethylimidazole in 10 mL glycerol and stir for 12 hours to obtain a uniform dispersion.

[0018] S2: Transfer the dispersion to a high-pressure reactor and react at 180 °C for 3 hours to obtain a white precursor powder.

[0019] S3: The precursor and sublimated S powder were physically mixed at a mass ratio of 1:3, and heated at a rate of 5℃ / min under an Ar atmosphere. -1 ZnS@C was obtained by calcining at 600℃ for 3 hours. The morphology of the electrode materials prepared in the above embodiments is as follows: Figure 1-5 As shown, the prepared negative electrode material was fabricated into a coin cell using a coin cell process, and the results were tested. The test results are shown in Table 1. The ZnS / CoS@C obtained by a combination of solvothermal method, one-step sulfidation, and heat treatment exhibits a flat nanorod shape. After calcination, the surface develops protrusions, increasing the specific area while maintaining the overall morphology. The GCD curve clearly shows that Example 1 exhibits a high specific capacity after the first charge-discharge cycle and still demonstrates excellent performance after 30 cycles.

[0020]

Claims

1. A method for preparing a high-performance sodium-ion battery negative electrode ZnS / CoS@C composite material, characterized in that, Includes the following steps: S1: Add zinc salt, cobalt salt and dimethylimidazole together to 10 mL of glycerol solution. S2: The above mixed solution is continuously stirred and dispersed to obtain a uniformly dispersed solution. S3: Transfer the dispersion to a high-pressure reactor for solvothermal reaction to obtain purple precursor powder. S4: The purple precursor powder is physically mixed with sublimed sulfur powder and placed in a tube furnace for calcination in an argon atmosphere to obtain ZnS / CoS@C nanorods.

2. The preparation method of the high-performance sodium-ion battery negative electrode ZnS / CoS@C composite material as described in claim 1, characterized in that, In step S1, the zinc salt is one or more of zinc chloride, zinc nitrate, and zinc sulfate.

3. The preparation method of the high-performance sodium-ion battery negative electrode ZnS / CoS@C composite material as described in claim 1, characterized in that, In step S1, the cobalt salt is one or more of cobalt chloride, cobalt nitrate, and cobalt sulfate.

4. The preparation method of the high-performance sodium-ion battery negative electrode ZnS / CoS@C composite material as described in claim 1, characterized in that, In step S2, the mixing time of the mixed solution is 12h to 24h.

5. The preparation method of the high-performance sodium-ion battery negative electrode ZnS / CoS@C composite material as described in claim 1, characterized in that, In step S3, the solvothermal reaction temperature is 150–180°C.

6. The method for preparing the high-performance sodium-ion battery negative electrode ZnS / CoS@C composite material as described in claim 1, characterized in that, In step S4, the purple precursor powder and sublimed sulfur powder are physically mixed by grinding or ball milling.

7. The method for preparing the high-performance sodium-ion battery negative electrode ZnS / CoS@C composite material as described in claim 1, characterized in that, In step S4, the sintering temperature is 500-600℃ and the time is 1-3h.

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