Copper-doped bismuth telluride topological insulator lithium-sulfur battery diaphragm material and preparation method thereof

Abstract

The invention provides a copper-doped bismuth telluride topological insulator lithium-sulfur battery diaphragm material and a preparation method thereof. The chemical formula of the copper-doped bismuth telluride topological insulator lithium-sulfur battery diaphragm material is Bi (2-x) CuxTe3, wherein the doping amount x of Cu is less than 10%. The topological structure of the surface of Bi2Te3 is changed through Cu doping, the carrier concentration of the surface is improved, meanwhile, when the Bi2Te3 is used as a battery diaphragm material of a lithium-sulfur battery, Cu doping can cause crystal defects, so that more sites are exposed, and Cu and sulfur species can form Cu-S bonds, so that the capturing capability of bismuth telluride on polysulfide is remarkably enhanced, and the performance of the Bi2Te3 is improved. By introducing Cu, the catalytic activity of Bi2Te3 on polysulfide conversion is improved, and the ionic conductivity is improved, so that the charge-discharge performance of the lithium-sulfur battery is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of topological insulator materials, and particularly relates to a copper-doped bismuth telluride topological insulator lithium-sulfur battery separator material and a preparation method thereof. BACKGROUND

[0002] Lithium-sulfur batteries are considered as a strong contender for the next generation of energy storage systems due to their many advantages. However, there is a shuttle effect in lithium-sulfur batteries, that is, during the charging and discharging process of the battery, some active substances or intermediate products will migrate back and forth between the positive and negative electrodes. This phenomenon is particularly common in lithium-sulfur batteries and has a significant negative impact on battery performance, which restricts the practical application of lithium-sulfur batteries.

[0003] In view of how to inhibit the shuttle effect, which is the most serious problem in lithium-sulfur batteries, researchers have developed many coping strategies, such as sulfur positive electrode host material design, separator modification, negative electrode protection, etc. Among them, separator modification is a relatively simple and effective strategy. Topological insulator materials in metal chalcogenides are emerging materials that have been recognized as having broad potential for energy conversion and storage. Topological insulators are a kind of topological quantum materials with bulk insulating and metallic properties at the edge or surface, which have a series of excellent characteristics such as protected surface states, narrow bulk band gap and high surface carrier mobility, bringing potential advantages for their application in energy conversion and storage. Some metal compounds have metallic properties or narrow band gaps, which can accelerate electron transfer and alleviate the insulating problem of sulfur, and have strong adsorption to lithium polysulfides (Li2S n , 4≤n≤8), which can effectively inhibit the shuttle effect.

[0004] As a typical topological insulator material, Bi2Te3 is considered an ideal lithium-sulfur battery modification material due to its unique electronic structure (topologically protected surface states) and two-dimensional layered structure. However, the adsorption and catalytic activity of Bi2Te3 to polysulfides need to be further improved. SUMMARY

[0005] The purpose of the present application is to overcome the shortcomings and deficiencies in the prior art, and to provide a copper-doped bismuth telluride topological insulator lithium-sulfur battery separator material. The introduction of Cu improves the catalytic activity of Bi2Te3 to polysulfide conversion and improves the ion conductivity, thereby improving the charging and discharging performance of lithium-sulfur batteries.

[0006] The present application is achieved by the following technical solutions:

[0007] The present application provides a copper-doped bismuth telluride topological insulator lithium-sulfur battery separator material, with a chemical formula of Bi 2- x Cu x Te3;wherein the doping amount x of Cu is less than 10%.

[0008] In the copper-doped bismuth telluride topological insulator lithium-sulfur battery separator material provided by this invention, the topological structure of the Bi2Te3 surface is changed by Cu doping, which increases the carrier concentration on the surface. At the same time, when used as a separator material for lithium-sulfur batteries, Cu doping will induce crystal defects, thereby exposing more sites. In addition, Cu and sulfur species can form Cu-S bonds, thus significantly enhancing the ability of bismuth telluride to capture polysulfides. The introduction of Cu improves the catalytic activity of Bi2Te3 for polysulfide conversion, improves ionic conductivity, and thus improves the charge and discharge performance of lithium-sulfur batteries.

[0009] Furthermore, the copper-doped bismuth telluride topological insulator lithium-sulfur battery separator material has a diameter of 200-800 nm and a thickness of 4-20 nm.

[0010] This invention also provides a method for preparing copper-doped bismuth telluride battery separator modification materials, comprising the following steps:

[0011] Bismuth source and sodium tellurite were dissolved in a reaction solvent and stirred until dissolved to obtain a first reaction solution. A copper source was added to the first reaction solution to obtain a second reaction solution. The second reaction solution was reacted at 160℃-240℃ to generate a reaction product. The reaction product was cooled to room temperature, centrifuged, washed, and dried to obtain a copper-doped bismuth telluride topological insulator lithium-sulfur battery separator material.

[0012] Further, in the step of adding a copper source to the first reaction solution to obtain the second reaction solution, the mass-to-volume ratio of the added copper source to the reaction solvent is (0-1.1):1, in mg / mL. The mass-to-volume ratio of the added copper source to the reaction solvent is controlled at (0-1.1):1, in mg / mL, to ensure that the copper doping ratio is no greater than 10%.

[0013] Further, in the step of adding a copper source to the first reaction solution to obtain the second reaction solution, the copper source includes, but is not limited to, at least one of copper nitrate, copper chloride, copper iodide, copper sulfate, or copper oxide.

[0014] Further, in the step of dissolving bismuth source and sodium tellurite in the reaction solvent and stirring until dissolved to obtain the first reaction solution, the mass-volume ratio of the amount of bismuth source added to the reaction solvent is (1-40):1, with units of mg / mL.

[0015] Further, in the step of dissolving the bismuth source and sodium tellurite in the reaction solvent and stirring until dissolved to obtain the first reaction solution, the bismuth source includes, but is not limited to, at least one of bismuth nitrate, bismuth chloride, bismuth oxide, bismuth nitrate-containing water of crystallization, bismuth chloride-containing water of crystallization, and bismuth oxide-containing water of crystallization.

[0016] Further, in the step of dissolving bismuth source and sodium tellurite in the reaction solvent and stirring until dissolved to obtain the first reaction solution, the surfactant is dissolved in the reaction solvent, a strong base is added to the reaction solvent, and then the bismuth source and sodium tellurite are added.

[0017] The present invention also provides the application of the above-mentioned bismuth telluride topological insulator lithium-sulfur battery separator material in the field of lithium-sulfur battery separators.

[0018] To better understand and implement this invention, the following detailed description is provided in conjunction with the accompanying drawings. Attached Figure Description

[0019] Figure 1 This is a flowchart illustrating the preparation method of a doped bismuth telluride topological insulator lithium-sulfur battery separator material.

[0020] Figure 2 This is the XRD pattern of a copper-doped bismuth telluride topological insulator lithium-sulfur battery separator material.

[0021] Figure 3 It's Bi 1.94 Cu 0.06 TEM images and b, d HRTEM images of Te3 and Bi2Te3.

[0022] Figure 4 It's Bi 1.94 Cu 0.06 Optical photographs of Te3 and Bi2Te3 interacting in Li2S6 solution for 24 h, and the corresponding UV-Vis spectra.

[0023] Figure 5 It's Bi 1.94 Cu 0.06 Lithium-sulfur batteries using Te3 as a separator modifier achieve a performance of 0.1 mV / s. -1 The CV curves for the first three cycles at the sweep speed.

[0024] Figure 6 Lithium-sulfur batteries using Bi2Te3 as the separator modification material achieve a performance of 0.1 mV / s. -1 The CV curves for the first three cycles at the sweep speed.

[0025] Figure 7 It's Bi 1.94 Cu 0.06 The cycling performance of lithium-sulfur batteries using Te3 and Bi2Te3 as membrane modification materials at 0.2C.

[0026] Figure 8 It's Bi 1.94 Cu 0.06 Te3, Bi2Te3, Bi 1.98 Cu 0.02 Te3, Bi1.92 Cu 0.08 The cycling performance of lithium-sulfur batteries with Te3 as the separator modification material at 1C.

[0027] Figure 9 It's Bi 1.94 Cu 0.06 The rate performance of lithium-sulfur batteries using Te3 and Bi2Te3 as separator modification materials at different current densities. Detailed Implementation

[0028] The embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and not intended to limit the scope of the invention. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the embodiments of the present invention, and not all structures.

[0029] Furthermore, the terms "first," "second," "third," etc., used in the specification and claims are only for the purpose of distinguishing the description of the same technical features and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated, nor necessarily the order of description or chronological sequence. Where appropriate, the terms are interchangeable. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature.

[0030] Similarly, the terms "fixed" and "connected" are used in the specification and claims and should not be construed as limited to a direct connection. Therefore, the expression "device A is connected to device B" should not be limited to device A being directly connected to device B in a device or system; it means that there is a path between device A and device B, which can be a path that includes other devices or tools.

[0031] Example 1

[0032] This embodiment provides a copper-doped bismuth telluride topological insulator lithium-sulfur battery separator material with the chemical formula Bi. 2- x Cu x Te3; wherein the Cu doping level x is less than 10%.

[0033] In the copper-doped bismuth telluride topological insulator lithium-sulfur battery separator material provided in this embodiment, the topological structure of the Bi2Te3 surface is changed by Cu doping, which increases the carrier concentration on the surface. At the same time, when used as a separator material for lithium-sulfur batteries, Cu doping will induce crystal defects, thereby exposing more sites. In addition, Cu and sulfur species can form Cu-S bonds, thus significantly enhancing the ability of bismuth telluride to capture polysulfides. The introduction of Cu improves the catalytic activity of Bi2Te3 for polysulfide conversion, improves ionic conductivity, and thus improves the charge and discharge performance of lithium-sulfur batteries.

[0034] In this invention, the Cu doping amount x is less than 10% to ensure that Cu doping is beneficial to improving the charge and discharge performance of lithium-sulfur batteries. If the Cu doping amount is too large, CuTe2 phase will be generated.

[0035] In this embodiment, the copper-doped bismuth telluride topological insulator lithium-sulfur battery separator material has a diameter of 200-800 nm and a thickness of 4-20 nm.

[0036] When using bismuth telluride topological insulator lithium-sulfur battery separator materials, the diameter is controlled to be 200-800 nm and the thickness to be 4-20 nm to improve the ability to capture polysulfides. In one embodiment, the copper-doped bismuth telluride topological insulator lithium-sulfur battery separator material has a diameter of 200 nm and a thickness of 4 nm. In another embodiment, the copper-doped bismuth telluride topological insulator lithium-sulfur battery separator material has a diameter of 200 nm and a thickness of 20 nm. In yet another embodiment, the copper-doped bismuth telluride topological insulator lithium-sulfur battery separator material has a diameter of 400 nm and a thickness of 10 nm.

[0037] The copper-doped bismuth telluride topological insulator lithium-sulfur battery separator material provided in this embodiment has a two-dimensional structure. As a separator material in lithium-sulfur batteries, it can significantly improve the electrochemical performance of lithium-sulfur batteries. The copper-doped bismuth telluride separator material has the characteristics of simple process equipment, high production efficiency, and small material consumption, making it suitable for widespread application.

[0038] Example 2

[0039] This embodiment provides a method for preparing the copper-doped bismuth telluride topological insulator lithium-sulfur battery separator material of Example 1. Figure 1 This is a flowchart illustrating the preparation method of copper-doped bismuth telluride topological insulator lithium-sulfur battery separator material. Please refer to [link / reference]. Figure 1 The preparation method of copper-doped bismuth telluride topological insulator lithium-sulfur battery separator material includes the following steps:

[0040] Step S1: Dissolve the bismuth source and sodium tellurite in the reaction solvent and stir until dissolved to obtain the first reaction solution;

[0041] Step S2: Add a copper source to the first reaction solution to obtain the second reaction solution;

[0042] Step S3: React the second reaction solution at 160℃-240℃ to generate the reaction product;

[0043] Step S4: Cool the reaction product to room temperature, centrifuge, wash, and dry to obtain copper-doped bismuth telluride topological insulator lithium-sulfur battery separator material.

[0044] In step S1, bismuth source and sodium tellurite are dissolved in the reaction solvent and stirred until dissolved to obtain the first reaction solution. In this process, surfactant is dissolved in the reaction solvent, a strong base is added to the reaction solvent, and then bismuth source and sodium tellurite are added.

[0045] In one embodiment, the reaction solvent includes one of water, methanol, ethanol, and ethylene glycol. The surfactant includes polyvinylpyrrolidone (PVP) with a weight-average molecular weight (Mw) of 60,000 g / mol, and the mass-to-volume ratio of PPVP to the reaction solvent is 2-100 mg / mL.

[0046] A strong base is added to provide an alkaline reaction environment. The strong base includes sodium hydroxide or potassium hydroxide. The mass-volume ratio of the added strong base to the reaction solvent is (10-30):1, with units of mg / mL.

[0047] In this embodiment, the bismuth source includes at least one of bismuth nitrate, bismuth chloride, bismuth oxide, bismuth nitrate-containing water of crystallization, bismuth chloride-containing water of crystallization, and bismuth oxide-containing water of crystallization.

[0048] The mass-to-volume ratio of bismuth source to reaction solvent is (1-40):1, in mg / mL. In step S2, copper source is added to the first reaction solution to obtain the second reaction solution, wherein the mass-to-volume ratio of copper source to reaction solvent is (0-1.1):1, in mg / mL. The mass-to-volume ratio of copper source to reaction solvent is controlled at (0-1.1):1, in mg / mL, to ensure that the copper doping ratio does not exceed 10%. If the Cu doping amount is too high, a CuTe2 phase will be formed.

[0049] In this embodiment, the copper source includes, but is not limited to, at least one of copper nitrate, copper chloride, copper iodide, copper sulfate, or copper oxide. The molar ratio of the added bismuth source, sodium tellurite, and copper source is 1:(1.5+0.5x):x; where x is the proportion of copper doping, and x is 0-10%.

[0050] In one embodiment, the copper source includes copper chloride, and the mass-volume ratio of the amount added to the reaction solvent is (0-1.1):1, in mg / mL.

[0051] Step S3: React the second reaction solution at 160℃-240℃ to generate the reaction product, wherein the reaction time is 12-48 hours to ensure the reaction is complete.

[0052] In step S4, the reaction product is cooled to room temperature, centrifuged, washed, and dried to obtain copper-doped bismuth telluride topological insulator lithium-sulfur battery membrane material. The drying temperature is 40-80℃ and the drying time is 8-20h. Methanol, ethanol, or acetone are used for centrifugation and washing.

[0053] Specifically, after the reaction product is cooled to room temperature, the product is collected by centrifugation and washed three times each with deionized water and organic solvent. Finally, it is dried in an oven at 40-80℃ for 8-20 hours to obtain copper-doped bismuth telluride topological insulator lithium-sulfur battery separator material.

[0054] Example 3

[0055] This embodiment provides a method for preparing the copper-doped bismuth telluride topological insulator lithium-sulfur battery separator material of Example 1, comprising the following steps:

[0056] Step S1: Dissolve the bismuth source and sodium tellurite in the reaction solvent and stir until dissolved to obtain the first reaction solution.

[0057] In one embodiment, a surfactant is dissolved in a reaction solvent, a strong base is added to the reaction solvent, followed by a bismuth source and sodium tellurite. The surfactant includes polyvinylpyrrolidone (PVP), the reaction solvent includes ethylene glycol, and the strong base includes NaOH. 0.5 g of PVP is added to 36 mL of ethylene glycol (EG) and stirred overnight until completely dissolved. Then, 0.4 g of NaOH is added to the reaction solvent and stirred for 30 min until completely dissolved. Finally, 0.315 g (1.0 mmol) of BiCl3 and 0.340 g (1.53 mmol) of Na2TeO3 are added, and the mixture is stirred vigorously to obtain a homogeneous first reaction solution.

[0058] Step S2: Add a copper source to the first reaction solution to obtain the second reaction solution.

[0059] In this embodiment, the copper source includes copper chloride. In one implementation, 8 mg (0.06 mmol) of CuCl2 is added to the first reaction solution, and the mixture is stirred vigorously for 1 hour to obtain the second reaction solution.

[0060] Step S3: React the second reaction solution at 160℃-240℃ to generate the reaction product.

[0061] In this embodiment, the second reaction solution was transferred to a 50 mL stainless steel high-pressure reactor lined with polytetrafluoroethylene, then the reactor was sealed and heated to 180°C for 36 h to generate the reaction product.

[0062] Step S4: Cool the reaction product to room temperature, centrifuge, wash, and dry to obtain copper-doped bismuth telluride topological insulator lithium-sulfur battery separator material.

[0063] In this embodiment, after the reaction product was cooled to room temperature, the precipitate was collected by centrifugation and washed three times each with deionized water and ethanol, and then dried in an oven at 60°C for 12 hours. The dried precipitate was collected to obtain a high-performance copper-doped bismuth telluride topological insulator lithium-sulfur battery membrane material Bi. 1.94 Cu 0.06 Te3.

[0064] Comparative Example 1

[0065] This comparative example provides a method for preparing the copper-doped bismuth telluride topological insulator lithium-sulfur battery separator material of Example 1, comprising the following steps:

[0066] Add 0.5 g of polyvinylpyrrolidone (PVP) to 36 mL of ethylene glycol (EG) and stir overnight until completely dissolved. Then add 0.4 g of NaOH to the reaction solvent and stir for 30 min until completely dissolved. Add 0.315 g (1.0 mmol) of BiCl3 and 0.332 g (1.50 mmol) of Na2TeO3 and stir vigorously to obtain a homogeneous first reaction solution.

[0067] The obtained first reaction solution was transferred to a 50 mL stainless steel high-pressure reactor lined with polytetrafluoroethylene, then the reactor was sealed and heated to 180 °C for 36 h to generate the reaction product.

[0068] After the reaction product was cooled to room temperature, the precipitate was collected by centrifugation and washed three times each with deionized water and ethanol. The precipitate was then dried in an oven at 60°C for 12 hours. The dried precipitate was collected to obtain the lithium-sulfur battery membrane material Bi2Te3.

[0069] The performance of the lithium-sulfur battery separator material Bi2Te3 prepared in this comparative example was tested.

[0070] Bi from Example 3 1.94 Cu 0.06 Te3 was used as the test sample, and Bi2Te3 of Comparative Example 1 was used as the control sample for performance characterization tests.

[0071] Bi was coated using a surface coating method 1.94 Cu0.06 Te3 is used to prepare and form the separator for the test sample battery:

[0072] 70wt% of sample Bi 1.94 Cu 0.06 Te3, 20 wt% carbon black (Super P), and 10 wt% polyvinylidene fluoride (PVDF) were thoroughly mixed in N-methylpyrrolidone (NMP) solvent to form a homogeneous slurry. This slurry was then coated onto a clean Celgard 2500 polypropylene (PP) separator to form a functionalized separator. The functionalized separator was vacuum dried overnight at 50°C, and then cut into discs with a diameter of 19 mm. The areal loading of the functionalized film as the interlayer material was approximately 0.3 mg / cm². -2 .

[0073] Bi2Te3 was used to prepare a comparative battery separator using a surface coating method:

[0074] 70 wt% of Bi₂Te₃, 20 wt% of carbon black (Super P), and 10 wt% of polyvinylidene fluoride (PVDF) were thoroughly mixed in N-methylpyrrolidone (NMP) solvent to form a homogeneous slurry. This slurry was then coated onto a clean Celgard 2500 polypropylene (PP) membrane to form a functionalized membrane. The functionalized membrane was vacuum-dried overnight at 50°C and then cut into 19 mm diameter discs. The areal loading of the functionalized film as the interlayer material was approximately 0.3 mg / cm². -2 .

[0075] Figure 2 This is the XRD pattern of a copper-doped bismuth telluride topological insulator lithium-sulfur battery separator material, in which... Figure 2 (a) shows the XRD patterns of the test sample and the control sample. Figure 2 (b) shows example diagrams of the characteristic peak shifts for the test and control samples, corresponding to crystal card ICSD#85-0439. Please refer to [link to ICSD#85-0439]. Figure 2 The copper-doped bismuth telluride topological insulator lithium-sulfur battery separator material has a trigonal crystal structure, corresponding to crystal card ICSD#85-0439, with unit cell parameters of... α=β=90°, γ=120°, test sample Bi 1.92 Cu 0..08 The characteristic peak of Te3 shifts to the left compared to the control sample Bi2Te3, the diffraction angle 2θ decreases, and the interplanar spacing d increases, indicating that Cu was successfully doped into Bi2Te3.

[0076] Figure 3 It's Bi 1.94 Cu 0.06TEM images and b, d HRTEM images of Te3 and Bi2Te3, among which Figure 3 (a) is a TEM image of Bi2Te3. Figure 3 (b) is the HRTEM image of Bi2Te3. Figure 3 (c) is Bi 1.94 Cu 0.06 TEM image of Te3 Figure 3 (d) is Bi 1.94 Cu 0.06 HRTEM plot of Te3. See also Figure 3 The test sample and the control sample were characterized by transmission electron microscopy (TEM). The test sample Bi... 1.94 Cu 0.06 Te3 exhibits a regular hexagonal plate-like morphology with a diameter of approximately 500 nm, and the lattice fringe spacing of the main peak (110) crystal plane is 0.232 nm, which is greater than that of the comparative sample Bi2Te3.

[0077] Figure 4 It's Bi 1.94 Cu 0.06 Optical photographs and corresponding UV-Vis spectra of Te3 and Bi2Te3 interacting in Li2S6 solution for 24 hours. (See also...) Figure 4 Contains test sample Bi 1.94 Cu 0.06 The UV-Vis absorption peak of Li2S6 was lowest in the Te3 solution, indicating that the tested sample Bi 1.94 Cu 0.06 Te3 has a stronger adsorption capacity for Li2S6 molecules.

[0078] Figure 5 It's Bi 1.94 Cu 0.06 Lithium-sulfur batteries using Te3 as a separator modifier achieve a performance of 0.1 mV / s. -1 The CV curves for the first three cycles at the sweep speed. Figure 6 Lithium-sulfur batteries using Bi2Te3 as the separator modification material achieve a performance of 0.1 mV / s. -1 The CV curves for the first three revolutions at the specified scan speed. Please refer to [link / reference]. Figure 5 and Figure 6 At 0.1mVs -1 Test sample Bi 1.94 Cu 0.06 The first three cycles of Te3 showed good coincidence of cyclic voltammetry (CV), proving that Bi 1.94 Cu 0.06 Te3 exhibits excellent catalytic stability. Compared to the control sample Bi2Te3 in Comparative Example 1, the tested sample has a larger peak current, demonstrating that it has better catalytic activity for polysulfide conversion.

[0079] Figure 7 It's Bi 1.94 Cu 0.06 Lithium-sulfur batteries using Te3 and Bi2Te3 as separator modification materials exhibited good cycle performance at 0.2C. A lithium-sulfur battery assembled with a Bi2Te3-PP separator showed an initial cycle capacity of 1285 mAh g / L at 0.2C. -1 The specific capacity was 46.5% after 100 cycles.

[0080] Figure 8 It's Bi 1.94 Cu 0.06 Te3, Bi2Te3, Bi 1.98 Cu 0.02 Te3, Bi 1.92 Cu 0.08 The cycling performance of lithium-sulfur batteries using Te3 as a separator modification material at 1C is described. Please refer to [link / reference]. Figure 7 , with Bi 1.94 Cu 0.06 The lithium-sulfur battery assembled with Te3-PP as the battery separator exhibited an initial charge of 1279.6 mAh g at 0.2C rate. -1 It has a high specific capacity, and after 100 cycles, the capacity retention rate is 54.6%, which is better than the 46.5% of the control sample Bi2Te3.

[0081] Figure 9 It's Bi 1.94 Cu 0.06 Rate performance of lithium-sulfur batteries using Te3 and Bi2Te3 as separator modifying materials at different current densities. (See also: [link to relevant documentation]) Figure 8 After doping modification, the test sample Bi 1.94 Cu 0.06 Te3 retains 676.6 mAh g after 200 cycles at 1C current density. -1 It exhibits high discharge capacity with a capacity retention rate exceeding 62.5%, which is higher than the 626.4 mAh g / L of the Bi2Te3-PP separator. -1 (53.7%). The rate performance of the battery was tested at different rates using Bi... 1.94 Cu 0.06 The capacity of the Te3-PP battery was superior to that of the Bi2Te3-PP separator at all rates, indicating that using Cu-doped Bi2Te3 as a separator for lithium-sulfur batteries can exhibit better battery performance.

[0082] Example 4

[0083] This embodiment provides a method for preparing the copper-doped bismuth telluride topological insulator lithium-sulfur battery separator material of Example 1, comprising the following steps:

[0084] Step S1: Dissolve the bismuth source and sodium tellurite in the reaction solvent and stir until dissolved to obtain the first reaction solution.

[0085] In one embodiment, a surfactant is dissolved in a reaction solvent, a strong base is added to the reaction solvent, followed by a bismuth source and sodium tellurite. The surfactant includes polyvinylpyrrolidone (PVP), the reaction solvent includes ethylene glycol, and the strong base includes NaOH. 0.5 g of PVP is added to 36 mL of ethylene glycol (EG) and stirred overnight until completely dissolved. Then, 0.4 g of NaOH is added to the reaction solvent and stirred for 30 min until completely dissolved. Finally, 0.315 g (1.0 mmol) of BiCl3 and 0.35 g (1.51 mmol) of Na2TeO3 are added, and the mixture is stirred vigorously to obtain a homogeneous first reaction solution.

[0086] Step S2: Add a copper source to the first reaction solution to obtain the second reaction solution.

[0087] In this embodiment, the copper source includes copper chloride. In one implementation, 3 mg (0.02 mmol) of CuCl2 is added to the first reaction solution, and the mixture is stirred vigorously for 1 hour to obtain the second reaction solution.

[0088] Step S3: React the second reaction solution at 160℃-240℃ to generate the reaction product.

[0089] In this embodiment, the second reaction solution was transferred to a 50 mL stainless steel high-pressure reactor lined with polytetrafluoroethylene, then the reactor was sealed and heated to 180°C for 36 h to generate the reaction product.

[0090] Step S4: Cool the reaction product to room temperature, centrifuge, wash, and dry to obtain copper-doped bismuth telluride topological insulator lithium-sulfur battery separator material.

[0091] In this embodiment, after the reaction product was cooled to room temperature, the precipitate was collected by centrifugation and washed three times each with deionized water and ethanol, and then dried in an oven at 60°C for 12 hours. The dried precipitate was collected to obtain a high-performance copper-doped bismuth telluride topological insulator lithium-sulfur battery membrane material Bi. 1.98 Cu 0.2 Te3.

[0092] Example 5

[0093] This embodiment provides a method for preparing the copper-doped bismuth telluride topological insulator lithium-sulfur battery separator material of Example 1, comprising the following steps:

[0094] Step S1: Dissolve the bismuth source and sodium tellurite in the reaction solvent and stir until dissolved to obtain the first reaction solution.

[0095] In one embodiment, a surfactant is dissolved in a reaction solvent, a strong base is added to the reaction solvent, followed by a bismuth source and sodium tellurite. The surfactant includes polyvinylpyrrolidone (PVP), the reaction solvent includes ethylene glycol, and the strong base includes NaOH. 0.5 g of PVP is added to 36 mL of ethylene glycol (EG) and stirred overnight until completely dissolved. Then, 0.4 g of NaOH is added to the reaction solvent and stirred for 30 min until completely dissolved. Finally, 0.315 g (1.0 mmol) of BiCl3 and 0.341 g (1.54 mmol) of Na2TeO3 are added, and the mixture is stirred vigorously to obtain a homogeneous first reaction solution.

[0096] Step S2: Add a copper source to the first reaction solution to obtain the second reaction solution.

[0097] In this embodiment, the copper source includes copper chloride. In one implementation, 11 mg (0.08 mmol) of CuCl2 is added to the first reaction solution, and the mixture is stirred vigorously for 1 hour to obtain the second reaction solution.

[0098] Step S3: React the second reaction solution at 160℃-240℃ to generate the reaction product.

[0099] In this embodiment, the second reaction solution was transferred to a 50 mL stainless steel high-pressure reactor lined with polytetrafluoroethylene, then the reactor was sealed and heated to 180°C for 36 h to generate the reaction product.

[0100] Step S4: Cool the reaction product to room temperature, centrifuge, wash, and dry to obtain copper-doped bismuth telluride topological insulator lithium-sulfur battery separator material.

[0101] In this embodiment, after the reaction product was cooled to room temperature, the precipitate was collected by centrifugation and washed three times each with deionized water and ethanol, and then dried in an oven at 60°C for 12 hours. The dried precipitate was collected to obtain a high-performance copper-doped bismuth telluride topological insulator lithium-sulfur battery membrane material Bi. 1.92 Cu 0..08 Te3.

[0102] Example 6

[0103] This embodiment provides a method for preparing the copper-doped bismuth telluride topological insulator lithium-sulfur battery separator material of Example 1, comprising the following steps:

[0104] Step S1: Dissolve the bismuth source and sodium tellurite in the reaction solvent and stir until dissolved to obtain the first reaction solution.

[0105] In one embodiment, a surfactant is dissolved in a reaction solvent, a strong base is added to the reaction solvent, followed by a bismuth source and sodium tellurite. The surfactant includes polyvinylpyrrolidone (PVP), the reaction solvent includes ethylene glycol, and the strong base includes NaOH. 0.5 g of PVP is added to 36 mL of ethylene glycol (EG) and stirred overnight until completely dissolved. Then, 0.4 g of NaOH is added to the reaction solvent and stirred for 30 min until completely dissolved. Finally, 0.315 g (1.0 mmol) of BiCl3 and 0.340 g (1.53 mmol) of Na2TeO3 are added, and the mixture is stirred vigorously to obtain a homogeneous first reaction solution.

[0106] Step S2: Add a copper source to the first reaction solution to obtain the second reaction solution.

[0107] In this embodiment, the copper source includes copper chloride. In one implementation, 8 mg (0.06 mmol) of CuCl2 is added to the first reaction solution, and the mixture is stirred vigorously for 1 hour to obtain the second reaction solution.

[0108] Step S3: React the second reaction solution at 160℃-240℃ to generate the reaction product.

[0109] In this embodiment, the second reaction solution was transferred to a 50 mL stainless steel high-pressure reactor lined with polytetrafluoroethylene, then the reactor was sealed and heated to 220°C for 36 h to generate the reaction product.

[0110] Step S4: Cool the reaction product to room temperature, centrifuge, wash, and dry to obtain copper-doped bismuth telluride topological insulator lithium-sulfur battery separator material.

[0111] In this embodiment, after the reaction product was cooled to room temperature, the precipitate was collected by centrifugation and washed three times each with deionized water and ethanol, and then dried in an oven at 60°C for 12 hours. The dried precipitate was collected to obtain a high-performance copper-doped bismuth telluride topological insulator lithium-sulfur battery membrane material Bi. 1.94 Cu 0..06 Te3.

[0112] Example 7

[0113] This embodiment provides a method for preparing the copper-doped bismuth telluride topological insulator lithium-sulfur battery separator material of Example 1, comprising the following steps:

[0114] Step S1: Dissolve the bismuth source and sodium tellurite in the reaction solvent and stir until dissolved to obtain the first reaction solution.

[0115] In one embodiment, a surfactant is dissolved in a reaction solvent, a strong base is added to the reaction solvent, followed by a bismuth source and sodium tellurite. The surfactant includes polyvinylpyrrolidone (PVP), the reaction solvent includes ethylene glycol, and the strong base includes NaOH. 0.5 g of PVP is added to 36 mL of ethylene glycol (EG) and stirred overnight until completely dissolved. Then, 0.4 g of NaOH is added to the reaction solvent and stirred for 30 min until completely dissolved. Finally, 0.4 g (1.27 mmol) of BiCl3 and 0.340 g (1.53 mmol) of Na2TeO3 are added, and the mixture is stirred vigorously to obtain a homogeneous first reaction solution.

[0116] Step S2: Add a copper source to the first reaction solution to obtain the second reaction solution.

[0117] In this embodiment, the copper source includes copper chloride. In one implementation, 11 mg (0.06 mmol) of CuCl2 is added to the first reaction solution, and the mixture is stirred vigorously for 1 hour to obtain the second reaction solution.

[0118] Step S3: React the second reaction solution at 160℃-240℃ to generate the reaction product.

[0119] In this embodiment, the second reaction solution was transferred to a 50 mL stainless steel high-pressure reactor lined with polytetrafluoroethylene, then the reactor was sealed and heated to 240°C for 36 h to generate the reaction product.

[0120] Step S4: Cool the reaction product to room temperature, centrifuge, wash, and dry to obtain copper-doped bismuth telluride topological insulator lithium-sulfur battery separator material.

[0121] In this embodiment, after the reaction product was cooled to room temperature, the precipitate was collected by centrifugation and washed three times each with deionized water and ethanol, and then dried in an oven at 60°C for 12 hours. The dried precipitate was collected to obtain a high-performance copper-doped bismuth telluride topological insulator lithium-sulfur battery membrane material Bi. 1.94 Cu 0.06 Te3.

[0122] Example 8

[0123] This embodiment provides a method for preparing the copper-doped bismuth telluride topological insulator lithium-sulfur battery separator material of Example 1, comprising the following steps:

[0124] Step S1: Dissolve the bismuth source and sodium tellurite in the reaction solvent and stir until dissolved to obtain the first reaction solution.

[0125] In one embodiment, a surfactant is dissolved in a reaction solvent, a strong base is added to the reaction solvent, followed by a bismuth source and sodium tellurite. The surfactant includes polyvinylpyrrolidone (PVP), the reaction solvent includes ethylene glycol, and the strong base includes NaOH. 0.5 g of PVP is added to 36 mL of ethylene glycol (EG) and stirred overnight until completely dissolved. Then, 0.4 g of NaOH is added to the reaction solvent and stirred for 30 min until completely dissolved. Finally, 0.01 g (0.0317 mmol) of BiCl3 and 0.340 g (1.53 mmol) of Na2TeO3 are added, and the mixture is stirred vigorously to obtain a homogeneous first reaction solution.

[0126] Step S2: Add a copper source to the first reaction solution to obtain the second reaction solution.

[0127] In this embodiment, the copper source includes copper chloride. In one implementation, 11 mg (0.06 mmol) of CuCl2 is added to the first reaction solution, and the mixture is stirred vigorously for 1 hour to obtain the second reaction solution.

[0128] Step S3: React the second reaction solution at 160℃-240℃ to generate the reaction product.

[0129] In this embodiment, the second reaction solution was transferred to a 50 mL stainless steel high-pressure reactor lined with polytetrafluoroethylene, then the reactor was sealed and heated to 160°C for 36 h to generate the reaction product.

[0130] Step S4: Cool the reaction product to room temperature, centrifuge, wash, and dry to obtain copper-doped bismuth telluride topological insulator lithium-sulfur battery separator material.

[0131] In this embodiment, after the reaction product was cooled to room temperature, the precipitate was collected by centrifugation and washed three times each with deionized water and ethanol, and then dried in an oven at 60°C for 12 hours. The dried precipitate was collected to obtain a high-performance copper-doped bismuth telluride topological insulator lithium-sulfur battery membrane material Bi. 1.94 Cu 0.06 Te3.

[0132] This invention is not limited to the above-described embodiments. If any modifications or variations to this invention do not depart from the spirit and scope of this invention, and if such modifications and variations fall within the scope of the claims and equivalent technologies of this invention, then this invention also intends to include such modifications and variations.

Claims

1. A copper-doped bismuth telluride topological insulator lithium-sulfur battery separator material, characterized in that: The chemical formula is Bi 2-x Cu x Te3, wherein the Cu doping amount x is less than 10%.

2. The copper-doped bismuth telluride topological insulator lithium-sulfur battery separator material according to claim 1, characterized in that: The copper-doped bismuth telluride topological insulator lithium-sulfur battery separator material has a diameter of 200-800 nm and a thickness of 4-20 nm.

3. A method for preparing the copper-doped bismuth telluride battery separator modification material according to any one of claims 1-2, characterized in that, Includes the following steps: The bismuth source and sodium tellurite were dissolved in the reaction solvent and stirred until dissolved to obtain the first reaction solution; A copper source is added to the first reaction solution to obtain the second reaction solution; The second reaction solution was reacted at 160℃-240℃. The reaction product was cooled to room temperature, centrifuged, washed, and dried to generate the reaction product. The reaction product was cooled to room temperature, centrifuged, washed, and dried to obtain copper-doped bismuth telluride topological insulator lithium-sulfur battery separator material.

4. The method for preparing the copper-doped bismuth telluride topological insulator lithium-sulfur battery separator material according to claim 3, characterized in that: In the step of adding a copper source to the first reaction solution to obtain the second reaction solution, the mass-volume ratio of the amount of copper source added to the reaction solvent is (0-1.1):1, in mg / mL.

5. The method for preparing the copper-doped bismuth telluride topological insulator lithium-sulfur battery separator material according to claim 4, characterized in that: In the step of adding a copper source to the first reaction solution to obtain the second reaction solution, the copper source includes, but is not limited to, at least one of copper nitrate, copper chloride, copper iodide, copper sulfate, or copper oxide.

6. The method for preparing the copper-doped bismuth telluride topological insulator lithium-sulfur battery separator material according to claim 3, characterized in that: In the step of dissolving bismuth source and sodium tellurite in the reaction solvent and stirring until dissolved to obtain the first reaction solution, the mass-volume ratio of the amount of bismuth source added to the reaction solvent is (1-40):1, with units of mg / mL.

7. The method for preparing the copper-doped bismuth telluride topological insulator lithium-sulfur battery separator material according to claim 6, characterized in that: In the step of dissolving bismuth source and sodium tellurite in a reaction solvent and stirring until dissolved to obtain the first reaction solution, the bismuth source includes, but is not limited to, at least one of bismuth nitrate, bismuth chloride, bismuth oxide, bismuth nitrate-containing water of crystallization, bismuth chloride-containing water of crystallization, and bismuth oxide-containing water of crystallization.

8. The method for preparing the copper-doped bismuth telluride topological insulator lithium-sulfur battery separator material according to claim 6, characterized in that: In the step of dissolving bismuth source and sodium tellurite in the reaction solvent and stirring until dissolved to obtain the first reaction solution, the surfactant is dissolved in the reaction solvent, a strong base is added to the reaction solvent, and then the bismuth source and sodium tellurite are added.

9. The application of the copper-doped bismuth telluride topological insulator lithium-sulfur battery separator material according to any one of claims 1-2 in the field of lithium-sulfur battery separators.

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