A method for preparing ReS2 two-dimensional superlattice structures and their applications

Abstract

The application provides a preparation method and application of a ReS2 two-dimensional superlattice structure, and single-layer carbon is inserted between two adjacent ReS2 monomolecular nanolayers, which has multiple effects: not only can the interlayer spacing of ReS2 be widened, but also the insertion and removal of alkali metal ions can be facilitated; the electronic conductivity of the surface and the interior of ReS2 can be improved, so that the transmission of electrons can be sufficiently accelerated; in addition, ReS2 is confined between two single-layer carbon structures, so that the solid-solid reaction activity in the charging and discharging process is improved. Such a unique nanostructure can also form a conductive network with carbon-based materials to form a strong framework, and has excellent nanostructure stability. The product obtained by the application has a unique structure, a regular morphology, a uniform composition, no impurity phase, and excellent electrochemical characteristics.

Description

Technical Field

[0001] This invention belongs to the field of electrochemical energy storage, specifically relating to a method for preparing a ReS2 two-dimensional superlattice structure and its application in potassium-ion batteries or sodium-ion batteries. Background Technology

[0002] Lithium-ion batteries are widely researched and used in electronic products of all sizes. The rapidly increasing demand for lithium resources is directly leading to a shortage. Potassium and sodium resources in the Earth's crust are about 1000 times more abundant than lithium. Potassium and sodium ions share many physical and chemical properties with lithium ions, and the operating principles of potassium-ion and sodium-ion batteries are similar to those of lithium-ion batteries. Based on these advantages and similarities, potassium-ion and sodium-ion batteries are ideal alternatives to lithium-ion batteries. However, potassium ions and sodium ions (… and The ionic radius of ions is much larger than that of lithium ions. This leads to problems such as structural damage, slow diffusion kinetics, and low structural stability in the anode material due to large-sized ion insertion / extraction when using traditional lithium-ion batteries. Therefore, developing a stable and adaptable structure to ensure long-term cycle stability and high reversible specific capacity of the battery is particularly crucial.

[0003] Transition metal dichalcogenides (TMDs) possess unique physical and chemical properties and are considered one of the most promising anode materials for alkaline ion batteries. Among them, rhenium disulfide (ReS2) nanosheets exhibit a large interlayer spacing (0.61 nm) and a high theoretical specific capacity (428 mAh g⁻¹). -1 ReS2 nanosheets have been extensively studied in sodium-ion batteries, but their cycling stability at high current densities and their application in potassium-ion batteries are rarely reported. Modifying the structure of ReS2 nanosheets is a common and effective strategy to address the problems of low intrinsic conductivity and structural collapse caused by volume changes during charge and discharge. The van der Waals gaps between adjacent layers of layered two-dimensional materials allow for the insertion of ions, atoms, molecules, and polymers without disrupting the covalent bonds within the layers. By adjusting the structure, composition, and size of the guest and host materials, a series of layered intercalation materials can be prepared, exhibiting highly tunable chemical and physical properties compared to the original materials. Due to the two-dimensional layered nature of ReS2, synthesizing stable ReS2 advanced composite materials with widened layer space, enhanced internal conductivity, and two-dimensional confined space for rapid potassium or sodium ion insertion / extraction has significant research value and practical application implications. Summary of the Invention

[0004] This invention addresses the problems of high cost, long production cycles, and difficulty in mass production of high-performance, ultra-stable potassium-ion or sodium-ion battery anodes by providing a low-cost, simple-to-process ReS2 two-dimensional superlattice structure suitable for mass production, as well as its application in potassium-ion or sodium-ion batteries. The material of this invention exhibits outstanding electrochemical storage performance.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] A method for preparing a ReS2 two-dimensional superlattice structure includes the following steps:

[0007] Step 1: Weigh 2-6 mmol of CH4N2S or C2H5NS and add it to 3-10 mL of deionized water. Stir for 1-20 minutes to obtain solution A.

[0008] Step 2: Take 20-400 mg of carbon-based material and add it to 15-30 mL of deionized water. Sonicate for 0.1-5 hours, then stir for 0.1-2 hours. Continue to add 0.5-1.5 mmol of NH4ReO4 and 2-6 mmol of NH3OHCl and stir for 1-40 minutes to obtain solution B.

[0009] Step 3: Add 1-6 mL of an amino compound and 0.5-8 g of a reducing sugar to solution B in sequence, stir for 1-20 minutes to obtain solution C;

[0010] Step 4: Quickly transfer the solution C to solution A, seal and stir for 10-40 minutes to obtain a mixed solution; transfer the mixed solution to a reaction vessel and react at 160-220℃ for 12-24 hours to obtain the initial product;

[0011] Step 5: After centrifuging and washing the initial product, place it in a vacuum drying oven to dry and obtain the intermediate product;

[0012] Step 6: Place the intermediate product in a tube furnace, then heat it to 500-900℃ in a vacuum environment, hold it for 1-3 hours, and finally cool it to room temperature to obtain the target product ReS2 two-dimensional superlattice structure, that is, a single-layer carbon intercalated ReS2 nanosheet grown on a carbon-based material.

[0013] Preferably, the carbon-based material is one of reduced graphene oxide (rGO), carbon nanotubes (CNT), carbon cloth (CC), carbon nanowires (CNW), and carbon spheres (HCS).

[0014] Preferably, the amino compound is ethylenediamine.

[0015] Preferably, the reducing sugar is glucose.

[0016] Preferably, the cleaning in step 5 involves sequentially cleaning with deionized water and anhydrous ethanol.

[0017] The ReS2 two-dimensional superlattice structure prepared by this invention can be used as a negative electrode material in potassium-ion batteries or sodium-ion batteries.

[0018] Compared with existing technologies, the beneficial effects of this invention are reflected in:

[0019] 1. This invention provides a method for preparing a two-dimensional superlattice structure of ReS2, the obtained product having a unique structure, regular morphology, uniform composition, no impurity phase, and excellent electrochemical properties.

[0020] 2. The present invention provides a two-dimensional superlattice structure of ReS2, in which a single layer of carbon is inserted between two adjacent ReS2 monolayer nanomolecules. This structure exhibits multiple effects: it not only widens the interlayer spacing of ReS2, facilitating rapid insertion / extraction of potassium or sodium ions; it also improves the surface and internal electronic conductivity of ReS2, thereby accelerating electron transport; furthermore, the confinement of ReS2 between the two single-layer carbon layers enhances solid-solid reaction activity. This unique nanostructure can also form a conductive network with carbon-based materials, creating a robust framework with excellent nanostructure stability.

[0021] 3. The ReS2 superlattice structure prepared by this invention exhibits excellent rate performance and superior long-term cycle life at high current densities, and possesses excellent potassium or sodium storage performance.

[0022] 4. This invention explores an economical and simple method for combining interlayer modulation and nanoscale engineering to modulate layered ReS2 structures to obtain advanced electrodes for high-performance rechargeable batteries, providing an effective synthesis scheme for the practical application of advanced anode materials in potassium-ion and sodium-ion batteries.

[0023] 5. The preparation process of this invention is simple, the preparation cost is low, and it is easy to synthesize and promote on a large scale. Attached Figure Description

[0024] Figure 1 The images are SEM images of the samples prepared in Examples 1 to 4 of this invention. In the images, a, b, c and d correspond to sample 1 (ReS2@C), sample 2 (rGO@ReS2@C), sample 3 (CNT@ReS2@C) and sample 4 (CC@ReS2@C), respectively.

[0025] Figure 2These are TEM images of the samples prepared in Examples 1 to 4 of the present invention. In the images, a, b, c, and d correspond to sample 1 (ReS2@C), sample 2 (rGO@ReS2@C), sample 3 (CNT@ReS2@C), and sample 4 (CC@ReS2@C), respectively.

[0026] Figure 3 The image shows the XPS plot of ReS2@C prepared in Example 1 of this invention. In the figure, a, b, c, and d correspond to Re 4f, S2p, C 1s, and N1s, respectively.

[0027] Figure 4 The XRD spectrum of the sample prepared for an embodiment of the present invention.

[0028] Figure 5 The Raman spectrum of the sample prepared in the embodiment of the present invention.

[0029] Figure 6 The variable rate performance curve of the potassium-ion battery assembled for the present invention.

[0030] Figure 7 The potassium-ion battery assembled for the present invention operates at a low current density of 0.5 Ag. –1 The following is a long-cycle performance graph.

[0031] Figure 8 The potassium-ion battery assembled for the present invention is based on a high current density of 2Ag. –1 The following is a long-cycle performance graph.

[0032] Figure 9 The sodium-ion battery assembled for the present invention has a high current density of 5 Ag –1 The following is a long-cycle performance graph. Detailed Implementation

[0033] The technical solution of the present invention will be described in detail below with reference to the embodiments. The following embodiments are implemented on the premise of the technical solution of the present invention, and detailed implementation methods and specific operation processes are given. However, the protection scope of the present invention is not limited to the following embodiments.

[0034] Unless otherwise specified, all process steps in the following embodiments are carried out at room temperature.

[0035] Example 1

[0036] This embodiment prepares ReS2@C according to the following steps:

[0037] Step 1: Weigh 3 mmol of CH4N2S and add it to 5 mL of deionized water. Stir for 10 minutes to obtain solution A.

[0038] Step 2: Weigh 1 mmol of NH4ReO4 and 5.7 mmol of NH3OHCl into 21 mL of deionized water and stir for 30 minutes to obtain solution B.

[0039] Step 3: Add 4 mL of C2H8N2 and 1 g of glucose to the above solution B in sequence, and continue stirring for 15 minutes to obtain solution C.

[0040] Step 4: Quickly transfer the above solution C to solution A, then seal the beaker with sealant and stir for 30 minutes to obtain a mixed solution; transfer the mixed solution to a 50 mL reaction vessel and react at 200 °C for 24 hours to obtain the initial product.

[0041] Step 5: After centrifuging and washing the initial product, place it in a vacuum drying oven at 60℃ and dry for 12 hours to obtain the intermediate product.

[0042] Step 6: Place the intermediate product in a tube furnace, and then heat it to 600°C in a vacuum environment at a heating rate of 5°C / min. Hold the temperature for 2 hours, and finally cool it naturally to room temperature to obtain the target product ReS2@C, which is denoted as Sample 1.

[0043] Example 2

[0044] This embodiment prepares rGO@ReS2@C according to the following steps:

[0045] Step 1: Weigh 3 mmol of CH4N2S and add it to 5 mL of deionized water. Stir for 10 minutes to obtain solution A.

[0046] Step 2: Take 4.5 mL of solution with a concentration of 4.5 mg / mL. –1 The GO solution was sonicated in 16.5 mL of deionized water for 2 hours, then stirred for 1 hour. 1 mmol of NH4ReO4 and 5.7 mmol of NH3OHCl were added and stirred for 20 minutes to obtain solution B.

[0047] Step 3: Add 4 mL of C2H8N2 and 1 g of glucose to the above solution B in sequence, and stir for 15 minutes to obtain solution C.

[0048] Step 4: Quickly transfer the above solution C to solution A, then seal the beaker with sealant and stir for 30 minutes to obtain a mixed solution; transfer the mixed solution to a 50 mL reaction vessel and react at 200 °C for 24 hours to obtain the initial product.

[0049] Step 5: After centrifuging and washing the initial product, place it in a vacuum drying oven at 60℃ and dry for 12 hours to obtain the intermediate product.

[0050] Step 6: Place the intermediate product in a tube furnace, and then heat it to 600°C in a vacuum environment at a heating rate of 5°C / min. Hold the temperature for 2 hours, and finally cool it naturally to room temperature to obtain the target product rGO@ReS2@C, which is denoted as sample 2.

[0051] Example 3

[0052] This embodiment prepares CNT@ReS2@C according to the following steps:

[0053] Step 1: Weigh 3 mmol of CH4N2S and add it to 5 mL of deionized water. Stir for 10 minutes to obtain solution A.

[0054] Step 2: Take 50 mg of CNT and sonicate it in 21 mL of deionized water for 2 hours, then stir for 1 hour. Continue to add 1 mmol of NH4ReO4 and 5.7 mmol of NH3OHCl and stir for 20 minutes to obtain solution B.

[0055] Step 3: Add 4 mL of C2H8N2 and 1 g of glucose to the above solution B in sequence, and stir for 15 minutes to obtain solution C.

[0056] Step 4: Quickly transfer the above solution C to solution A, then seal the beaker with sealant and stir for 30 minutes to obtain a mixed solution; transfer the mixed solution to a 50 mL reaction vessel and react at 200 °C for 24 hours to obtain the initial product.

[0057] Step 5: After centrifuging and washing the initial product, place it in a vacuum drying oven at 60℃ and dry for 12 hours to obtain the intermediate product.

[0058] Step 6: Place the intermediate product in a tube furnace, and then heat it to 600°C in a vacuum environment at a heating rate of 5°C / min. Hold the temperature for 2 hours, and finally cool it naturally to room temperature to obtain the target product CNT@ReS2@C, which is designated as sample 3.

[0059] Example 4

[0060] This embodiment prepares CC@ReS2@C according to the following steps:

[0061] Step 1: Weigh 3 mmol of CH4N2S and add it to 5 mL of deionized water. Stir for 10 minutes to obtain solution A.

[0062] Step 2: Take a 5cm long and 5cm wide CC (about 300mg) and sonicate it in 21mL of deionized water for 2 hours, then stir for 1 hour. Continue to add 1mmol of NH4ReO4 and 5.7mmol of NH3OHCl and stir for 20 minutes to obtain solution B.

[0063] Step 3: Add 4 mL of C2H8N2 and 1 g of glucose to the above solution B in sequence, and stir for 15 minutes to obtain solution C.

[0064] Step 4: Quickly transfer the above solution C to solution A, then seal the beaker with sealant and stir for 30 minutes to obtain a mixed solution; transfer the mixed solution to a 50 mL reaction vessel and react at 200 °C for 24 hours to obtain the initial product.

[0065] Step 5: After centrifuging and washing the initial product, place it in a vacuum drying oven at 60℃ and dry for 12 hours to obtain the intermediate product.

[0066] Step 6: Place the intermediate product in a tube furnace, and then heat it to 600°C in a vacuum environment at a heating rate of 5°C / min. Hold the temperature for 2 hours, and finally cool it naturally to room temperature to obtain the target product CC@ReS2@C, which is designated as sample 4.

[0067] Figure 1 The images show SEM images of the samples obtained in each embodiment. a, b, c, and d correspond to samples 1 (ReS2@C), 2 (rGO@ReS2@C), 3 (CNT@ReS2@C), and 4 (CC@ReS2@C), respectively. In sample 1 (ReS2@C), ReS2 nanosheets were prepared and stacked into large nanospheres through a hydrothermal process, where carbon was gathered and coated. In sample 2 (rGO@ReS2@C), ReS2 nanosheets and monolayer carbon were alternately stacked and uniformly distributed on rGO. In sample 3 (CNT@ReS2@C), ReS2 nanosheets were stacked and uniformly distributed on CNTs. In sample 4 (CC@ReS2@C), ReS2 was grown on the surface of carbon cloth (CC).

[0068] Figure 2The images show TEM images of the samples obtained in the above embodiments. a, b, c, and d correspond to samples 1 (ReS2@C), 2 (rGO@ReS2@C), 3 (CNT@ReS2@C), and 4 (CC@ReS2@C), respectively. Sample 1 (ReS2@C) shows ReS2 nanosheets peeled into few layers, with ReS2 completely coated by amorphous carbon. Amorphous carbon is inserted internally, forming a two-dimensional superlattice interlayer extension structure, with a measured interlayer spacing of 0.90 nm. In Sample 2 (rGO@ReS2@C), the ReS2 ordered on rGO is composed of stacked multilayer nanosheets with good crystallinity. Two adjacent ReS2 monolayers are intercalated with an amorphous carbon monolayer, forming a two-dimensional superlattice interlayer extension structure where ReS2 and monolayer carbon overlap. The (001) crystal plane extension of ReS2 is measured to be 0.98 nm. Similarly, in Sample 3 (CNT@ReS2@C) and Sample 4 (CC@ReS2@C), the nanosheets uniformly distributed on CNT and CC are formed by stacking ReS2 with good crystallinity.

[0069] Figure 3 a, b, c, and d in the figure are the high-resolution XPS spectra of Re 4f, S2p, C 1s, and N 1s of sample 1 (ReS2@C), respectively. Figure 3 The peaks at 44.33 and 41.93 eV in a correspond to Re 4f5 / 2 and Re 4f7 / 2, indicating that Re is in the +4 valence state. Meanwhile, the peaks at 45.48 and 42.28 eV belong to Re–O bonds caused by slight surface oxidation. Figure 3 b is the high-resolution spectrum of S2p, with peaks at 163.28 and 162.23 eV corresponding to S2p1 / 2 and S2p3 / 2, respectively. 2– Price state. Figure 3 c represents the high-resolution spectrum of C1s, with peaks at 288.23, 285.63, and 284.63 eV corresponding to C=O, CN, and CC chemical bonds, respectively. Figure 3 The high-resolution spectrum of N1s (d) can be divided into two different nitrogen peaks: pyrrolic–N at 401.03 eV and pyridinic–N at 398.68 eV. Electrochemically active pyridinic–N and pyrrolic–N can provide abundant external defects and active sites. The doping of carbon with nitrogen further improves the electronic conductivity of carbon.

[0070] Figure 4The XRD patterns of the samples obtained in the above embodiments are shown. Compared with the diffraction peaks of ReS2 (JCPDS 52-0818), the most significant (001) diffraction peak is located at 14.59°, corresponding to a ReS2 (001) interlayer spacing of 0.61 nm. The ReS2 (001) diffraction peaks of samples 1 (ReS2@C), 2 (rGO@ReS2@C), and 3 (CNT@ReS2@C) shift from 14.59° to around 8.99°. Calculations using the Scherrer equation 2dsinθ=nλ show that the ReS2 (001) interlayer spacing extends to approximately 0.98 nm.

[0071] Figure 5 The images show the Raman spectra of the samples obtained in the above embodiments. The spectra of sample 1 (ReS2@C), sample 2 (rGO@ReS2@C), and sample 3 (CNT@ReS2@C) are all at 146.2 cm⁻¹. –1 There is a significant peak at 157.1 cm⁻¹. –1 There is a secondary peak at this point, corresponding to the in-plane vibration mode of the Re-S bond (E). g ), at 206.2cm –1 The peak at that point corresponds to the out-of-plane vibration mode of the Re-S bond (A). g (At 1350 and 1590cm) –1 There are also two broadened peaks, which correspond to sp3-coordinated disordered carbon (D band) and sp2-coordinated graphitized carbon (G band) in carbon materials, respectively.

[0072] To characterize the electrochemical performance of the samples obtained in the above examples, the following tests were performed.

[0073] Step 1: Take the samples prepared in each example and grind them with graphite and sodium carboxymethyl cellulose in an agate mortar at a mass ratio of 6:2:2 to form a uniform slurry. Coat the slurry onto copper foil and then dry it in a vacuum drying oven at 80°C for 12 hours to make it into the working electrode of the battery.

[0074] Step 2: Using a potassium or sodium metal sheet as the counter electrode, glass microfiber filter paper (GF / D, Whatman) as the separator, 1.0M KFSI dissolved in ethylene carbonate (EC) and dimethyl carbonate (DMC) (EC:DMC = 1:1 Vol%) is used as the electrolyte for the potassium-ion battery, and 1.0M NaPF6 dissolved in diethylene glycol dimethyl ether (DEGDME) is used as the electrolyte for the sodium-ion battery. Assemble the CR2032 button cell in an inflatable glove box (Etelux Lab 200, O2 < 0.1ppm, H2O < 0.1ppm).

[0075] Step 3: Use Neware's CT4008T 5V / 10mA / 50mA system to perform battery charge and discharge tests on the assembled button batteries within a voltage window of 0.01-3.00V.

[0076] Figure 6 The rate performance curves of potassium-ion button cells assembled from samples 1 (ReS2@C), 2 (rGO@ReS2@C), and 3 (CNT@ReS2@C) are shown. Sample 2 (rGO@ReS2@C) exhibits superior potassium storage rate performance at current densities of 0.2, 0.5, 1, 2, and 5 A g, respectively. –1 It exhibits 324, 290, 262, 232, and 185 mAh g. –1 The high discharge specific capacity indicates that the ReS2 two-dimensional superlattice structure has a greater advantage in carbon-based materials.

[0077] Figure 7 Potassium-ion button cells assembled for samples 1 (ReS2@C), 2 (rGO@ReS2@C), and 3 (CNT@ReS2@C) were tested at a low current density of 0.5 Ag. –1 The cycling curves are shown below. Sample 2 (rGO@ReS2@C) had a specific capacity of 184 mAh g after 200 cycles. –1 The calculated capacity retention was 64.1%, demonstrating excellent stability. Sample 1 (ReS2@C) and Sample 3 (CNT@ReS2@C) had a capacity retention of 230 mAh g⁻¹ in the first cycle. –1 and 265mAh g –1 It exhibits excellent reversible specific capacity, demonstrating outstanding discharge specific capacity, and its coulombic efficiency (CE) during cycling remains at approximately 99%.

[0078] Figure 8 Long-term cycling performance curves of the potassium-ion coin cell assembled for Sample 2 (rGO@ReS2@C) under high current testing. Sample 2 at 2Ag –1 It exhibits excellent stability, with a discharge capacity of 226 mAh g during the initial cycle. –1 and maintained 107 mAh g after 300 cycles. –1 It has a capacity that demonstrates outstanding long-term cycling capability and a coulombic efficiency (CE) that is maintained at approximately 99.5%.

[0079] Figure 9 Long-term cycling performance curves of sodium-ion coin cells assembled for Sample 2 (rGO@ReS2@C) under high current testing. Sample 2 at 5Ag –1 It exhibits excellent stability, with a discharge capacity of 288 mAh g during the initial cycle. –1It maintains a capacity of 274 mAh g after 2000 cycles. –1 It exhibits excellent long-term cycling stability with its capacity, and its coulombic efficiency (CE) remains at approximately 100%.

[0080] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing a ReS2 two-dimensional superlattice structure, characterized in that, Includes the following steps: Step 1: Weigh 2-6 mmol of CH4N2S or C2H5NS and add it to 3-10 mL of deionized water. Stir for 1-20 minutes to obtain solution A. Step 2: Take 20-400 mg of carbon-based material and add it to 15-30 mL of deionized water. Sonicate for 0.1-5 hours, then stir for 0.1-2 hours. Continue to add 0.5-1.5 mmol of NH4ReO4 and 2-6 mmol of NH3OHCl and stir for 1-40 minutes to obtain solution B. Step 3: Add 1-6 mL of an amino compound and 0.5-8 g of a reducing sugar to solution B in sequence, stir for 1-20 minutes to obtain solution C; Step 4: Quickly transfer the solution C to solution A, seal and stir for 10-40 minutes to obtain a mixed solution; transfer the mixed solution to a reaction vessel and react at 160-220℃ for 12-24 hours to obtain the initial product; Step 5: After centrifuging and washing the initial product, place it in a vacuum drying oven to dry and obtain the intermediate product; Step 6: Place the intermediate product in a tube furnace, then heat it to 500-900℃ in a vacuum environment, hold it for 1-3 hours, and finally cool it to room temperature to obtain the target product ReS2 two-dimensional superlattice structure, that is, a single-layer carbon intercalated ReS2 nanosheet grown on a carbon-based material.

2. The preparation method according to claim 1, characterized in that: The carbon-based material is one of reduced graphene oxide, carbon nanotubes, carbon cloth, carbon nanowires, and carbon spheres.

3. The preparation method according to claim 1, characterized in that: The amino compound mentioned is ethylenediamine.

4. The preparation method according to claim 1, characterized in that: The reducing sugar mentioned is glucose.

5. The preparation method according to claim 1, characterized in that: The cleaning described in step 5 involves sequentially cleaning with deionized water and anhydrous ethanol.

6. A ReS2 two-dimensional superlattice structure prepared by the preparation method according to any one of claims 1 to 5.

7. The application of the ReS2 two-dimensional superlattice structure of claim 6 as a negative electrode material in potassium-ion batteries or sodium-ion batteries.

Images