Preparation method and application of hollow sphere CoNi2S4@C nanocomposite
Hollow spherical CoNi2S4@C nanocomposites were prepared by a solvothermal method, which solved the problem of uncontrollable morphology of CoNi2S4 materials in the prior art and improved the electrochemical performance and cycle stability of sodium-ion batteries.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- HEFEI UNIV
- Filing Date
- 2024-08-03
- Publication Date
- 2026-05-19
AI Technical Summary
Existing technologies make it difficult to efficiently and easily prepare CoNi2S4 nanocomposites with controllable morphology, resulting in insufficient conductivity and cycle stability in sodium-ion batteries.
Hollow spherical CoNi2S4@C nanocomposites were synthesized by a solvothermal method. By controlling the ratio of cobalt, nickel, and sulfur sources and adding hexadecyltrimethylammonium bromide and glucose, nanomaterials with high specific surface area and porosity were prepared, and the carbon coating structure on the surface was stable.
This improved the specific capacity and cycle performance of sodium-ion battery anode materials, mitigated volume changes during charge and discharge, and achieved efficient and stable sodium-ion electrochemical storage.
Smart Images
Figure CN118983412B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of sodium-ion battery anode material technology, specifically relating to a method for preparing and applying a hollow spherical CoNi2S4@C nanocomposite material. Background Technology
[0002] In recent years, with the widespread application of lithium-ion batteries in energy storage and electric vehicles, their limitations have gradually become apparent. These include cost issues due to limited lithium resources, capacity decay at low temperatures, and safety concerns during use. These unfavorable factors have hindered the further development of lithium-ion batteries. Sodium and lithium belong to the same group and share many similar physicochemical properties. Furthermore, sodium resources are abundant, widely distributed, and inexpensive. Sodium-ion batteries are less prone to sodium deposition at the negative electrode during rapid charging and discharging, exhibiting high safety and good low-temperature performance. Therefore, sodium-ion batteries are considered a next-generation electrochemical energy storage technology with great application potential.
[0003] CoNi2S4, as a novel anode material for sodium-ion batteries, possesses advantages such as relatively abundant resources, high theoretical capacity, good conductivity, stable thermal and mechanical properties, and Na+. + With its advantages such as good diffusion kinetics and environmental friendliness, it is a promising anode material for sodium-ion batteries.
[0004] Currently, most methods for preparing transition metal sulfides, including CoNi2S4, use solid-state vapor deposition (CVD). This method is not only cumbersome and complex with poor reproducibility, but also produces CoNi2S4 particles that are large and whose morphology is mostly uncontrollable. As a result, the conductivity of the material is still not ideal, and it cannot adapt to large volume changes during repeated sodium insertion / extraction processes, leading to electrode pulverization and poor cycle stability.
[0005] Therefore, finding a simple, highly reproducible, and morphology-controllable method to prepare CoNi2S4 nanocomposites to achieve efficient, stable, and safe electrochemical storage of sodium ions is of significant research value and importance. Summary of the Invention
[0006] Given that carbon coating and morphology control are effective strategies for modifying electrode materials, this invention addresses the shortcomings of current CoNi2S4 anode materials by providing a method for preparing hollow spherical CoNi2S4@C nanocomposites that is simple to prepare, highly reproducible, and exhibits excellent electrochemical performance.
[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:
[0008] A method for preparing hollow spherical CoNi2S4@C nanocomposite material is disclosed. The method involves a solvothermal synthesis, in which cobalt, nickel, and sulfur sources are first dissolved in ethylene glycol solution. Then, hexadecyltrimethylammonium bromide (CTAB) and glucose are added and mixed thoroughly. The reaction solution is then placed in a reaction vessel to undergo a solvothermal reaction. After the reaction is completed, the hollow spherical CoNi2S4@C nanocomposite material is obtained through post-treatment.
[0009] As a preferred embodiment of the present invention, the cobalt source, nickel source and sulfur source are added in an atomic ratio of 1:2:6, and the molar concentration of cobalt atoms in the reaction system is 0.01 to 0.05 mol / L.
[0010] As a preferred embodiment of the present invention, the cobalt source is cobalt acetate, cobalt nitrate, or cobalt chloride; the nickel source is nickel acetate, nickel nitrate, or nickel chloride; and the sulfur source is sodium thiosulfate or sodium sulfide.
[0011] As a preferred embodiment of the present invention, the molar concentration of hexadecyltrimethylammonium bromide in the reaction system is 0.05–0.20 mol / L, and the molar concentration of glucose in the reaction system is 0.01–0.05 mol / L.
[0012] As a preferred embodiment of the present invention, the cetyltrimethylammonium bromide (CTAB) and glucose are added and stirred for 0.5 to 2 hours at a stirring speed of 400 to 500 r / min.
[0013] As a preferred embodiment of the present invention, the solvothermal reaction temperature is 160-200°C and the reaction time is 18-24 hours.
[0014] As a preferred technical solution of the present invention, the post-treatment is to remove the upper layer solution by high-speed centrifugation after the reaction is completed, thereby obtaining a black precipitate, which is then washed several times by centrifugation with ethanol and deionized water, and then dried under vacuum to obtain hollow spherical CoNi2S4@C nanomaterials.
[0015] This invention prepares hollow spherical CoNi2S4@C nanocomposites from cobalt, nickel, and sulfur sources via a one-step solvothermal method. These nanocomposites possess high specific surface area and porosity, effectively increasing their contact area with the electrolyte. Furthermore, they contain numerous chemically active sites on their surface and interior, resulting in higher specific capacity when used as a negative electrode material in sodium-ion batteries. Additionally, the introduction of the carbon coating structure stabilizes the hollow spherical structure and provides good rigidity, effectively mitigating the volume expansion problem of the electrode material during charge and discharge. Therefore, the hollow spherical CoNi2S4@C nanomaterials prepared in this invention can effectively improve the structural stability and sodium storage performance of sodium-ion battery negative electrode materials.
[0016] Compared with the prior art, the beneficial effects of the present invention are also manifested in:
[0017] (1) The present invention uses a one-step solvothermal method for preparation, which is simple and fast, with a short experimental cycle, low cost and high repeatability.
[0018] (2) The CoNi2S4@C material prepared by the method of this invention is in the form of nano-hollow spheres with a diameter of 400-600 nm. It has the characteristics of large specific surface area and good conductivity. Its large specific surface area increases the contact area between the electrode material and the electrolyte, providing more active sites for electrochemical reactions; its large porosity is conducive to the rapid diffusion of sodium-ion batteries; its surface carbon coating structure and internal hollow structure can effectively alleviate the volume change during the charging and discharging process, thus exhibiting high reversible capacity, as well as excellent rate performance and cycle performance.
[0019] (3) The hollow spherical CoNi2S4@C nanocomposite material prepared in this invention has high reversible capacity and excellent rate and cycle performance when used as a negative electrode material for sodium-ion batteries. Attached Figure Description
[0020] Figure 1 The image shows the XRD pattern of the hollow spherical CoNi2S4@C nanocomposite material prepared in Example 1 of this invention.
[0021] Figure 2 Scanning electron microscope (SEM) image of the hollow spherical CoNi2S4@C nanocomposite material prepared in Example 1 of this invention.
[0022] Figure 3 Transmission electron microscopy and mapping images of the hollow spherical CoNi2S4@C nanocomposite material prepared in Example 1 of this invention.
[0023] Figure 4 The Raman spectrum of the hollow spherical CoNi2S4@C nanocomposite material prepared in Example 1 of this invention.
[0024] Figure 5 The rate performance curve of a sodium-ion battery assembled using the hollow spherical CoNi2S4@C nanocomposite material prepared in Example 1 of this invention as the negative electrode material is shown.
[0025] Figure 6 The image shows the cycle performance curve of a sodium-ion battery assembled using the hollow spherical CoNi2S4@C nanocomposite material prepared in Example 1 of this invention as the negative electrode material, at 10C.
[0026] Figure 7 Electrochemical impedance spectroscopy curves of the hollow spherical CoNi2S4@C nanocomposite material prepared in Example 1 of this invention. Detailed Implementation
[0027] The preparation scheme of the hollow spherical CoNi2S4@C nanocomposite material in the embodiments of the present invention is clearly described below with reference to the accompanying drawings. The described embodiments are only some embodiments of the present invention, not all embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. The structure, morphology and properties of the product obtained by the method of the present invention are characterized and analyzed by field emission scanning electron microscopy (FE-SEM, SU8010) and chemical composition is characterized by X-ray powder diffraction (XRD, Smart Lab).
[0028] Example 1
[0029] The preparation method of hollow spherical CoNi2S4@C nanocomposite materials is as follows:
[0030] Step 1: Weigh 0.1245g of cobalt acetate (tetrahydrate), 0.249g of nickel acetate (tetrahydrate), and 0.747g of sodium thiosulfate (pentahydrate) and add them to 30mL of ethylene glycol.
[0031] Step 2: Add 1g of hexadecyltrimethylammonium bromide and 0.1g of glucose to the solution obtained in Step 1, mix and stir for 1 hour at a speed of 500r / min.
[0032] Step 3: Transfer the solution obtained in Step 2 to a stainless steel reactor lined with polytetrafluoroethylene, and keep it at 180°C for 20 hours using a forced-air drying oven.
[0033] Step 4: After the reaction is complete, the supernatant is removed by centrifugation to obtain a black precipitate. The precipitate is washed multiple times by centrifugation with ethanol and deionized water. The obtained sample is then placed in a vacuum drying oven and dried under vacuum at 80°C for 12 hours.
[0034] Please refer to the following: Figures 1-4 7. X-ray diffraction analysis of the sample prepared in Example 1 revealed that its structure was consistent with CoNi2S4 (JCPDS: 24-0334), indicating that CoNi2S4@C was successfully prepared using this method. Field emission scanning electron microscopy and transmission electron microscopy were used to observe the sample, revealing that the prepared CoNi2S4@C nanocomposite material has a spherical structure with a diameter of 400–600 nm, a hollow interior, a rough surface, and uniform carbon coating. Raman spectroscopy of the sample showed that its I... D (Disordered or defective carbon) / I G The ratio of (graphite carbon) to carbon is 1.11, indicating that the sample has a lot of defect structures and good electrical conductivity.
[0035] The hollow spherical CoNi2S4@C nanocomposite material prepared in this embodiment was fabricated into a slurry and coated onto the surface of copper foil. This slurry was then assembled with a sodium sheet to form a half-cell, and its electrochemical performance was tested. The electrochemical test results are as follows: Figure 5 , 6 As shown, at a current density of 10 A / g, the initial discharge specific capacity is as high as 689.98 mAh / g, and after 1000 charge-discharge cycles, its capacity retention rate is as high as 71.84%, demonstrating high reversible capacity, as well as good rate and cycle performance.
[0036] Example 2
[0037] The preparation method of hollow spherical CoNi2S4@C nanocomposite materials is as follows:
[0038] Step 1: Weigh 0.249g of cobalt acetate (tetrahydrate), 0.498g of nickel acetate (tetrahydrate), and 1.494g of sodium thiosulfate (pentahydrate) and add them to 30mL of ethylene glycol.
[0039] Step 2: Add 2g of hexadecyltrimethylammonium bromide and 0.2g of glucose to the solution obtained in Step 1, mix and stir for 2 hours at a speed of 500r / min.
[0040] Step 3: Transfer the solution obtained in Step 2 to a stainless steel reactor lined with polytetrafluoroethylene, and keep it at 200°C for 24 hours using a forced-air drying oven.
[0041] Step 4: After the reaction is complete, the supernatant is removed by centrifugation to obtain a black precipitate. The precipitate is washed multiple times by centrifugation with ethanol and deionized water. The obtained sample is then placed in a vacuum drying oven and dried under vacuum at 80°C for 12 hours.
[0042] The hollow spherical CoNi2S4@C nanocomposite material prepared in this embodiment was coated onto the surface of copper foil as a slurry, and then assembled with a sodium sheet to form a half-cell. Its electrochemical performance was then tested. The electrochemical test results showed that at a current density of 10 A / g, the initial discharge specific capacity was 663.02 mAh / g, and after 1000 charge-discharge cycles, its capacity retention was 70.92%.
[0043] Example 3
[0044] The preparation method of hollow spherical CoNi2S4@C nanocomposite materials is as follows:
[0045] Step 1: Weigh 0.1245g of cobalt acetate (tetrahydrate), 0.249g of nickel acetate (tetrahydrate), and 0.747g of sodium thiosulfate (pentahydrate) and add them to 30mL of ethylene glycol.
[0046] Step 2: Add 0.75g of cetyltrimethylammonium bromide and 0.08g of glucose to the solution obtained in Step 1, mix and stir for 0.5h at a speed of 400r / min.
[0047] Step 3: Transfer the solution obtained in Step 2 to a stainless steel reactor lined with polytetrafluoroethylene, and keep it at 160°C for 18 hours using a forced-air drying oven.
[0048] Step 4: After the reaction is complete, the supernatant is removed by centrifugation to obtain a black precipitate. The precipitate is washed multiple times by centrifugation with ethanol and deionized water. The obtained sample is then placed in a vacuum drying oven and dried under vacuum at 80°C for 12 hours.
[0049] The hollow spherical CoNi2S4@C nanocomposite material prepared in this embodiment was coated onto the surface of copper foil as a slurry, and then assembled with a sodium sheet to form a half-cell. Its electrochemical performance was then tested. The electrochemical test results showed that at a current density of 10 A / g, the initial discharge specific capacity was 647.24 mAh / g, and after 1000 charge-discharge cycles, its capacity retention was 70.21%.
[0050] The above description is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the concept of the invention or exceed the scope defined in the claims, they should all fall within the protection scope of the present invention.
Claims
1. A method for preparing hollow spherical CoNi2S4@C nanocomposite material, synthesized by a solvothermal method, characterized in that, First, cobalt, nickel, and sulfur sources are dissolved in ethylene glycol solution at an atomic ratio of 1:2:6, with a cobalt molar concentration of 0.01–0.05 mol / L. Next, hexadecyltrimethylammonium bromide (CTAB) and glucose are added, with CTAB and glucose molar concentrations of 0.05–0.20 mol / L and 0.01–0.05 mol / L, respectively. The mixture is stirred thoroughly, and then placed in a reaction vessel for a solvothermal reaction at 160–200 °C for 18–24 h. After the reaction, the mixture is centrifuged, washed, and vacuum dried to obtain hollow spherical CoNi2S4@C nanocomposite material.
2. The preparation method according to claim 1, characterized in that, The cobalt source is cobalt acetate, cobalt nitrate, or cobalt chloride; the nickel source is nickel acetate, nickel nitrate, or nickel chloride; and the sulfur source is sodium thiosulfate or sodium sulfide.
3. The preparation method according to claim 1, characterized in that, After the cetyltrimethylammonium bromide (CTAB) and glucose are added, they are stirred and mixed for 0.5 to 2 hours at a stirring speed of 400 to 500 r / min.
4. The preparation method according to claim 1, characterized in that, After the reaction was completed, the upper layer of solution was removed by high-speed centrifugation to obtain a black precipitate. The precipitate was washed several times by centrifugation with ethanol and deionized water, and then vacuum dried to obtain hollow spherical CoNi2S4@C nanomaterials.
5. The CoNi2S4@C nanomaterial prepared by the method according to any one of claims 1 to 4, characterized in that... The microstructure is in the form of nanospheres with a hollow interior, and the diameter of the spheres is 400~600 nm.
6. The hollow spherical CoNi2S4@C nanocomposite material prepared by any one of claims 1 to 4, or as described in claim 5, is used as a negative electrode material for sodium-ion batteries.