A bismuth telluride / antimony telluride heterojunction anode catalyst for lithium-air batteries and a preparation method thereof
By using a bismuth telluride/antimony telluride heterojunction cathode catalyst in lithium-air batteries, the problem of poor catalyst performance in air environments in existing technologies has been solved, achieving high capacity and long lifespan electrochemical performance, especially exhibiting excellent cycle stability in real air environments.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHANDONG UNIV
- Filing Date
- 2024-09-27
- Publication Date
- 2026-07-07
AI Technical Summary
Existing lithium-air battery cathode catalysts exhibit poor electrochemical performance in real-world air environments, mainly due to the generation of byproducts caused by impurities such as H2O and CO2, and the catalytic anisotropy of two-dimensional materials is not fully utilized.
A bismuth telluride/antimony telluride heterojunction cathode catalyst is used. By epitaxially growing antimony telluride on the surface of bismuth telluride to form a lateral heterojunction, the adsorption energy of the stacked surface and the utilization rate of surface active sites are improved, and an interfacial electric field is formed to promote electron transfer and cathode reaction kinetics.
The initial discharge capacity in a pure oxygen environment is as high as 15000mAh/g or more, and the cycle life is as long as 650 cycles or more; in an air environment, the initial discharge capacity can still reach more than 8000mAh/g, and the cycle life can reach more than 350 cycles, which significantly improves the electrochemical performance of lithium-air batteries.
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Figure CN121748412B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of lithium-air battery technology, and in particular to a bismuth telluride / antimony telluride heterojunction cathode catalyst for lithium-air batteries, its preparation method, and its application. Background Technology
[0002] The information disclosed in the background section of this invention is intended only to enhance the understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.
[0003] With increasing global energy demand, humanity is placing higher demands on the energy density of energy storage devices. Current research on the energy density of lithium-ion batteries is nearing its theoretical limit, thus necessitating the development of energy storage devices with even higher energy densities. Lithium-air batteries, as metal-air batteries with the highest theoretical energy density, are considered highly promising candidates. Currently, most research on lithium-air batteries focuses on the O2 environment, primarily using Li2O2 as the discharge product. However, its insulating and insoluble nature leads to slow positive electrode reaction kinetics, resulting in high overpotential and poor cycle performance. Furthermore, in real-world ambient air, the presence of H2O and CO2 causes the formation of LiOH and Li2CO3, accelerating battery failure and limiting its practical application. Positive electrode catalysts are one effective measure to address these problems.
[0004] Two-dimensional materials (2D materials) have been extensively studied due to their layered structure, good electronic conductivity, and stability, and have demonstrated excellent performance in lithium-oxygen batteries. However, 2D materials with van der Waals forces exhibit significant catalytic anisotropy due to the difference in electron distribution between their stacked surface and side surfaces. The low adsorption energy at the stacked surface leads to underutilization of surface active sites, while the extremely high adsorption energy on the side surfaces results in the generation of byproducts. Therefore, balancing the catalytic activity of the stacked surface and side surfaces is crucial for improving their performance. Furthermore, most current cathode catalysts only achieve excellent cycle performance in a pure O2 environment. In air, the low levels of H2O, CO2, and O2 lead to the formation of various discharge products, such as Li2CO3 and LiOH, resulting in poor performance of the cathode catalysts. To date, there are few reports on cathode catalysts that achieve excellent electrochemical performance in real-world air environments. Therefore, providing a lithium-air battery cathode material with high catalytic activity and good electrochemical performance in real-world air environments is an urgent problem to be solved. Summary of the Invention
[0005] In view of this, the present invention provides a bismuth telluride / antimony telluride heterojunction cathode catalyst for lithium-air batteries, its preparation method and application. The two-dimensional lateral bismuth telluride / antimony telluride heterojunction constructed by the present invention improves the adsorption energy and utilization rate of surface active sites on the stacked surface, which helps to alleviate the catalytic anisotropy of two-dimensional materials and improves their cycle performance in lithium-oxygen batteries. At the same time, it can still maintain excellent electrochemical performance in lithium-air batteries under actual air conditions.
[0006] In a first aspect, the present invention provides a bismuth telluride / antimony telluride heterojunction cathode catalyst for lithium-air batteries, comprising bismuth telluride / antimony telluride nanosheets, wherein the bismuth telluride / antimony telluride nanosheets are obtained by epitaxially growing antimony telluride on the surface of bismuth telluride to form a lateral heterojunction.
[0007] Preferably, the diameter of the bismuth telluride / antimony telluride nanosheets is 500–1200 nm, and the thickness of the bismuth telluride / antimony telluride nanosheets is 30–100 nm.
[0008] Preferably, the molar ratio of bismuth telluride to antimony telluride is 1:(0.2~1).
[0009] Secondly, the present invention provides a method for preparing the above-mentioned bismuth telluride / antimony telluride heterojunction cathode catalyst for lithium-air batteries, comprising the following steps:
[0010] The first solution is prepared by dissolving bismuth telluride, antimony source, tellurium source, first reducing agent and first surfactant in a first solvent to undergo a first solvothermal reaction.
[0011] Preferably, the tellurium source is selected from one or two of sodium tellurite or tellurium powder; the antimony source is selected from one or more of antimony chloride, potassium antimony tartrate, or antimony oxide; the first reducing agent is selected from one or more of hydrazine hydrate, ammonia, sodium hydroxide, sodium borohydride, hydroxylamine, or ethylenediamine; the first surfactant is selected from one or more of ethylenediaminetetraacetic acid, hexadecyltrimethylammonium bromide, sodium dodecylbenzenesulfonate, and polyvinylpyrrolidone; and the first solvent is selected from one or two of ethylene glycol or water.
[0012] Preferably, the temperature of the first solvothermal reaction is 170–220°C, and the time of the first solvothermal reaction is 8–24 h.
[0013] Preferably, the ratio of the amount of bismuth telluride, antimony source, tellurium source, first reducing agent, first surfactant and first solvent is (0.2-1.3) mmol:(0.4-0.6) mmol:(0.6-0.9) mmol:(0.8-1) g:(0.3-0.5) g:(20-40) mL.
[0014] Preferably, the bismuth telluride is obtained by dissolving a bismuth source, a tellurium source, a second reducing agent, and a second surfactant in a second solvent to undergo a second solvothermal reaction.
[0015] Furthermore, the bismuth source is selected from one or more of bismuth chloride, bismuth nitrate, or bismuth oxide; the tellurium source of the bismuth telluride is selected from one or two of sodium tellurite or potassium tellurite; the second reducing agent is selected from one or more of hydrazine hydrate, ammonia, sodium hydroxide, sodium borohydride, hydroxylamine, or ethylenediamine; the second surfactant is selected from one or more of ethylenediaminetetraacetic acid, hexadecyltrimethylammonium bromide, sodium dodecylbenzenesulfonate, and polyvinylpyrrolidone; and the second solvent is selected from one or two of ethylene glycol or isopropanol.
[0016] Furthermore, the temperature of the second solvothermal reaction is 170–220°C, and the time of the second solvothermal reaction is 8–24 h.
[0017] Furthermore, the ratio of the amount of bismuth source, tellurium source, second reducing agent, second surfactant and second solvent is (0.5-0.7) mmol:(0.8-1) mmol:(0.4-0.6) g:(0.6-0.8) g:(20-40) mL.
[0018] Thirdly, the present invention provides a lithium-air battery, the lithium-air battery comprising a lithium metal anode, a cathode, and an electrolyte; the cathode comprising the bismuth telluride / antimony telluride heterojunction cathode catalyst for lithium-air batteries described in the first aspect above or the bismuth telluride / antimony telluride heterojunction cathode catalyst for lithium-air batteries prepared by the preparation method described in the second aspect above.
[0019] Compared with the prior art, the present invention has achieved the following beneficial effects:
[0020] (1) In this invention, bismuth telluride / antimony telluride heterojunction material is used as the positive electrode catalyst of lithium-air battery. Due to the inherent semiconductor properties of bismuth telluride / antimony telluride heterojunction material, an interfacial electric field is formed at the PN junction heterojunction interface, which is conducive to electron transfer and positive electrode reaction kinetics. At the same time, it increases the adsorption energy of the material surface for adsorbate, improves the anisotropy of the material, and is conducive to the formation and decomposition of discharge products. Therefore, when it is used as a positive electrode catalyst, it can improve the specific capacity of the battery, reduce the overpotential, and improve the cycle stability.
[0021] (2) When the bismuth telluride / antimony telluride heterojunction cathode catalyst of the present invention is applied to a lithium-air battery, the lithium-oxygen battery has an initial discharge capacity of more than 15,000 mAh / g at a current density of 500 mA / g in a pure oxygen environment; the cycle life is more than 650 cycles at a high current density of 1,000 mA / g and a cutoff capacity of 500 mAh / g; in an air environment, the lithium-air battery can still reach more than 8,000 mAh / g at an initial discharge capacity of 500 mA / g, and can cycle more than 350 cycles at a high current density of 1,000 mA / g and a cutoff capacity of 500 mAh / g, maintaining excellent cycle performance. Attached Figure Description
[0022] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention and do not constitute an undue limitation thereof. Obviously, those skilled in the art can obtain other drawings based on these drawings without any inventive effort.
[0023] Figure 1 These are SEM, TEM, and HRTEM images of the Bi2Te3 / Sb2Te3 heterojunction material of Embodiment 1 of the present invention;
[0024] Figure 2 This is the elemental distribution diagram of the Bi2Te3 / Sb2Te3 heterojunction material of Embodiment 1 of the present invention;
[0025] Figure 3 These are the XRD patterns of the material samples from Example 1 and Comparative Examples 1-2 of this invention;
[0026] Figure 4 The first discharge / charge curves of lithium-air batteries assembled from the Bi2Te3 / Sb2Te3 heterojunction material of Example 1, the Bi2Te3 material of Comparative Example 1, and the Sb2Te3 material of Comparative Example 2 in an oxygen environment at a current density of 500 mA / g are shown.
[0027] Figure 5 The lithium-air battery assembled from the Bi2Te3 / Sb2Te3 heterojunction material of Example 1, the Bi2Te3 material of Comparative Example 1, and the Sb2Te3 material of Comparative Example 2 exhibits cycling performance in an oxygen environment at a current density of 1000 mA / g and a cutoff capacity of 500 mAh / g.
[0028] Figure 6The lithium-air battery assembled from the Bi2Te3 / Sb2Te3 heterojunction material of Example 1, the Bi2Te3 material of Comparative Example 1, and the Sb2Te3 material of Comparative Example 2 is shown as the first discharge / charge curve in an air environment at a current density of 500 mA / g.
[0029] Figure 7 The lithium-air battery assembled from the Bi2Te3 / Sb2Te3 heterojunction material of Example 1, the Bi2Te3 material of Comparative Example 1, and the Sb2Te3 material of Comparative Example 2 exhibits its cycling performance in an air environment at a current density of 1000 mA / g and a cutoff capacity of 500 mAh / g. Detailed Implementation
[0030] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.
[0031] This invention provides a bismuth telluride / antimony telluride heterojunction cathode catalyst for lithium-air batteries, comprising bismuth telluride / antimony telluride nanosheets, wherein the bismuth telluride / antimony telluride nanosheets are obtained by growing antimony telluride on the surface of bismuth telluride to form a lateral heterojunction.
[0032] This invention reveals that when bismuth telluride (Bi₂Te₃) or antimony telluride (Sb₂Te₃) materials are used alone as positive electrode catalysts in lithium-air batteries, the cycle performance is poor. At a current density of 1000 mA / g and a cutoff capacity of 500 mAh / g, the number of cycles is less than 500 in an oxygen environment and less than 300 in an air environment. The low adsorption energy on the stacked surface of Bi₂Te₃ materials indicates insufficient utilization of surface active sites, while the extremely high adsorption energy on the stacked sides leads to the generation of byproducts, thus affecting its cycle performance. Sb₂Te₃ materials exhibit better cycle stability in an oxygen environment than Bi₂Te₃ materials, but worse cycle stability in an air environment. This is mainly due to the reduced O₂ content in the air and the generation of other byproducts.
[0033] When bismuth telluride / antimony telluride heterojunction materials are used as positive electrode catalysts in lithium-air batteries, the inherent semiconductor properties of bismuth telluride / antimony telluride heterojunction materials create an interfacial electric field at the PN junction heterojunction interface, which is beneficial to electron transfer and positive electrode reaction kinetics. At the same time, it improves the adsorption energy of the stacked surface and the utilization rate of surface active sites, improves the anisotropy of the two-dimensional material, and is conducive to the formation and decomposition of discharge products. Therefore, it can exhibit excellent electrochemical performance.
[0034] In this invention, the bismuth telluride / antimony telluride nanosheets have a diameter of 500–1200 nm and a thickness of 30–100 nm. The bismuth telluride / antimony telluride nanosheets of this invention exhibit a two-dimensional transverse hexagonal morphology.
[0035] In this invention, the molar ratio of bismuth telluride to antimony telluride is 1:(0.2-1), more preferably 1:(0.4-0.6).
[0036] The present invention also provides a method for preparing the above-mentioned bismuth telluride / antimony telluride heterojunction cathode catalyst for lithium-air batteries, comprising the following steps:
[0037] The first solution is prepared by dissolving bismuth telluride, antimony source, tellurium source, first reducing agent and first surfactant in a first solvent to undergo a first solvothermal reaction.
[0038] This invention grows antimony telluride on the surface of bismuth telluride through a solvothermal reaction, thereby forming a transverse heterojunction structure.
[0039] The present invention does not impose any special restrictions on the order and steps of adding the above raw materials, as long as a homogeneous and stable solution can be formed.
[0040] In this invention, the tellurium source is selected from one or two of sodium tellurite or tellurium powder. In one or more embodiments of this invention, the tellurium source is preferably sodium tellurite. The antimony source is selected from one or more of antimony chloride, potassium antimony tartrate, or antimony oxide. In one or more embodiments of this invention, the antimony source is preferably antimony chloride. The tellurium source and antimony source of this invention can be selected from hydrated salts of the above compounds, and this invention does not impose any special limitations on them.
[0041] In this invention, the first reducing agent is selected from one or more of hydrazine hydrate, ammonia, sodium hydroxide, sodium borohydride, hydroxylamine, or ethylenediamine, with sodium hydroxide being preferred; the first surfactant is selected from one or more of ethylenediaminetetraacetic acid, hexadecyltrimethylammonium bromide, sodium dodecylbenzenesulfonate, and polyvinylpyrrolidone, with polyvinylpyrrolidone being preferred; the first solvent is selected from one or two of ethylene glycol or water, with ethylene glycol being preferred.
[0042] In this invention, the temperature of the first solvothermal reaction is 170–220°C, more preferably 180–200°C; and the time of the first solvothermal reaction is 8–24 h, more preferably 10–15 h.
[0043] In this invention, the ratio of the amount of bismuth telluride, antimony source, tellurium source, first reducing agent, first surfactant and first solvent is (0.2-1.3) mmol:(0.4-0.6) mmol:(0.6-0.9) mmol:(0.8-1) g:(0.3-0.5) g:(20-40) mL.
[0044] In this invention, the bismuth telluride is obtained by dissolving a bismuth source, a tellurium source, a second reducing agent, and a second surfactant in a second solvent to undergo a second solvothermal reaction.
[0045] In this invention, the bismuth source is selected from one or more of bismuth chloride, bismuth nitrate, or bismuth oxide, preferably bismuth chloride; the tellurium source of the bismuth telluride is selected from one or two of sodium tellurite or tellurium powder, preferably sodium tellurite; the second reducing agent is selected from one or more of hydrazine hydrate, ammonia, sodium hydroxide, sodium borohydride, hydroxylamine, or ethylenediamine, preferably sodium hydroxide; the second surfactant is selected from one or more of ethylenediaminetetraacetic acid, hexadecyltrimethylammonium bromide, sodium dodecylbenzenesulfonate, and polyvinylpyrrolidone, preferably polyvinylpyrrolidone; the second solvent is selected from one or two of ethylene glycol or water, preferably ethylene glycol.
[0046] In this invention, the temperature of the second solvothermal reaction is 170–220°C, more preferably 180–200°C; and the time of the second solvothermal reaction is 8–24 h, more preferably 10–15 h.
[0047] In this invention, the ratio of the amount of bismuth source, tellurium source, second reducing agent, second surfactant and second solvent is (0.5-0.7) mmol:(0.8-1) mmol:(0.4-0.6) g:(0.6-0.8) g:(20-40) mL.
[0048] The present invention further includes a step of purifying and drying the reaction product after the first solvothermal reaction and the second solvothermal reaction are completed. The present invention does not impose any special restrictions on the purification and drying steps, and commonly used purification and drying methods in the art can be used.
[0049] The present invention also provides a lithium-air battery, the lithium-air battery comprising a lithium metal anode, a cathode and an electrolyte; the cathode comprising the above-mentioned bismuth telluride / antimony telluride heterojunction cathode catalyst for lithium-air batteries or the bismuth telluride / antimony telluride heterojunction cathode catalyst for lithium-air batteries prepared by the above preparation method.
[0050] When the bismuth telluride / antimony telluride heterojunction cathode catalyst of this invention is applied to lithium-air batteries, in a pure oxygen environment, the lithium-oxygen battery exhibits an initial discharge capacity of over 15000 mAh / g at a current density of 500 mA / g; at a high current density of 1000 mA / g and a cutoff capacity of 500 mAh / g, the cycle life reaches over 650 cycles; in an air environment, the lithium-air battery can still achieve an initial discharge capacity of over 8000 mAh / g at 500 mA / g, and can cycle over 350 times at a high current density of 1000 mA / g and a cutoff capacity of 500 mAh / g, maintaining excellent cycle performance.
[0051] This invention does not impose any special limitations on the preparation method of the positive electrode in lithium-air batteries; any commonly used method in the art for preparing lithium-air battery positive electrodes may be used. Similarly, this invention does not impose any special limitations on the electrolyte in lithium-air batteries; any commonly used electrolyte in the art may be used.
[0052] The technical solution of the present invention will be further described below with reference to specific embodiments. The amount of reactants in each step of the embodiments does not affect the use of other steps. If the amount of reaction product is insufficient for other steps, it can be prepared multiple times to meet the requirements of other steps.
[0053] Example 1
[0054] This embodiment provides a method for preparing a bismuth telluride / antimony telluride heterojunction cathode catalyst for lithium-air batteries.
[0055] (1) Weigh 0.48g of sodium hydroxide and dissolve it in 30mL of ethylene glycol. Stir the mixture magnetically in a reaction vessel and heat it to 100℃.
[0056] (2) Add 0.29 g bismuth nitrate pentahydrate (0.6 mmol), 0.20 g sodium tellurite (0.9 mmol), and 0.67 g polyvinylpyrrolidone to the solution obtained in step (1), and then carry out a solvothermal reaction at 190 °C for 30 min. After the reaction is cooled, wash the reaction product with a mixture of isopropanol / acetone and dry at room temperature for 12 h to obtain Bi2Te3 material.
[0057] (3) Take 0.4g of Bi2Te3 material (0.5mmol) obtained in step (2), 0.11g of antimony chloride (0.5mmol), 0.17g of sodium tellurite (0.75mmol), 0.9g of sodium hydroxide, and 0.4g of polyvinylpyrrolidone and dissolve them in 25mL of ethylene glycol solution. Perform a solvothermal reaction at 190℃ for 12h. After the reaction, wash the reaction product with a mixture of isopropanol / acetone and dry at room temperature for 12h to obtain Bi2Te3 / Sb2Te3 heterojunction material with a molar ratio of Bi2Te3 to Sb2Te3 of 1:0.5.
[0058] Figure 1 In the image, 'a' is a SEM image of the Bi2Te3 / Sb2Te3 heterojunction material of Example 1 of the present invention. It can be seen that after adding Sb to Bi2Te3, the lateral dimension is 700-1000 nm and the nanosheet thickness is 40-80 nm. Figure 1 As can be seen from b, Sb2Te3 grows epitaxially along the Bi2Te3 hexagonal nanosheets while still maintaining the hexagonal shape. Figure 1 In the figure, c represents the arrangement of surface atoms, corresponding to the (110) plane of Bi2Te3 and the (110) plane of Sb2Te3. Figure 1 In the image, d represents the HRTEM image of the side of the nanosheet, corresponding to the (003) plane of Sb2Te3. Figure 2 The elemental distribution diagram of the Bi2Te3 / Sb2Te3 heterojunction material in Example 1 of the present invention shows that the Sb element is concentrated on the outer side of the hexagonal nanosheets, and the Te element is uniformly distributed. This indicates that Sb2Te3 has successfully grown laterally along the surface of Bi2Te3.
[0059] Example 2
[0060] Compared with Example 1, the difference in this embodiment is that in step (3) of this embodiment, the amount of Bi2Te3 material added is 1.25 mmol, and the molar ratio of Bi2Te3 to Sb2Te3 in the final Bi2Te3 / Sb2Te3 heterojunction material is 1:0.2.
[0061] Example 3
[0062] Compared with Example 1, the difference in this embodiment is that in step (3) of this embodiment, the amount of Bi2Te3 material added is 0.31 mmol, and the molar ratio of Bi2Te3 to Sb2Te3 in the final Bi2Te3 / Sb2Te3 heterojunction material is 1:0.8.
[0063] Example 4
[0064] Compared with Example 1, the difference in this embodiment is that in step (3) of this embodiment, the amount of Bi2Te3 material added is 0.25 mmol, and the molar ratio of Bi2Te3 to Sb2Te3 in the final Bi2Te3 / Sb2Te3 heterojunction material is 1:1.
[0065] Comparative Example 1
[0066] The difference between this comparative example and Example 1 is that step (3) is not performed, and the final Bi2Te3 material is obtained.
[0067] Comparative Example 2
[0068] The difference between this comparative example and Example 1 is that step (2) is omitted in this comparative example. The specific steps are as follows:
[0069] (1) Weigh 0.48g of sodium hydroxide and dissolve it in 30mL of ethylene glycol. Stir the mixture magnetically in a reaction vessel and heat it to 100℃.
[0070] (2) 0.14 g antimony chloride (0.6 mmol), 0.20 g sodium tellurite (0.9 mmol), and 0.67 g polyvinylpyrrolidone were added to the solution obtained in step (1), and a solvothermal reaction was carried out at 190 °C for 12 h. After the reaction was completed, the product was washed with a mixture of isopropanol and acetone and dried at room temperature for 12 h to obtain Sb2Te3 material.
[0071] Figure 3 The XRD patterns of the material samples in Example 1 and Comparative Examples 1-2 of this invention show that all the peaks match well with the peaks of Bi2Te3 (PDF#15-0863) and Sb2Te3 (PDF#15-0874), proving the successful synthesis of Bi2Te3 / Sb2Te3 heterojunction.
[0072] Application examples
[0073] The Bi2Te3 / Sb2Te3 heterojunction material of Example 1, the Bi2Te3 material of Comparative Example 1, and the Sb2Te3 material of Comparative Example 2 were used as positive electrode catalysts for lithium-air batteries. The preparation method of the lithium-air battery is as follows: the positive electrode catalyst, Ketjen Black (KB), and polytetrafluoroethylene (PTFE) were mixed in an isopropanol solution at a mass ratio of 6:3:1 to form a uniform slurry. The slurry was coated onto a circular carbon paper with a diameter of 19 mm and dried at 120°C for 12 h in a vacuum drying oven. Then, the positive electrode shell, positive electrode catalyst, separator, lithium metal, steel sheet, spring sheet, and negative electrode shell were assembled into a 2023 type button battery. The electrolyte was tetraethylene glycol dimethyl ether (TEGDME) containing 1M lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and the separator was glass fiber.
[0074] Figure 4 The first discharge / charge curves of lithium-air batteries assembled from the Bi2Te3 / Sb2Te3 heterojunction material of Example 1, the Bi2Te3 material of Comparative Example 1, and the Sb2Te3 material of Comparative Example 2 are shown in an oxygen environment at a current density of 500 mA / g. The Bi2Te3 / Sb2Te3 electrode shows a current density of 15334.5 mAh g. -1 Its high specific capacity is superior to the 12586.9 mAh g of the Bi2Te3 electrode. -1 12217.7 mAh g of Sb2Te3 electrode -1 .
[0075] Figure 5 The lithium-air batteries assembled from the Bi2Te3 / Sb2Te3 heterojunction material of Example 1, the Bi2Te3 material of Comparative Example 1, and the Sb2Te3 material of Comparative Example 2 exhibited cycling performance in an oxygen environment at a current density of 1000 mA / g and a cutoff capacity of 500 mAh / g. The three electrodes achieved cycle lives of 697, 312, and 453 cycles, respectively.
[0076] Figure 6 The lithium-air batteries assembled from the Bi2Te3 / Sb2Te3 heterojunction material of Example 1, the Bi2Te3 material of Comparative Example 1, and the Sb2Te3 material of Comparative Example 2 exhibit their initial discharge / charge curves in air at a current density of 500 mA / g. At a discharge cutoff voltage range of 2.35 V, the discharge specific capacities of the three electrodes are 8593.1 mAh / g. -1 5474.5mAhg -1 and 4337.6mAhg -1 The overpotentials were 0.35V, 0.4V, and 0.58V, respectively. The Bi2Te3 / Sb2Te3 electrode still exhibits excellent specific capacity and low overpotential.
[0077] Figure 7 The lithium-air batteries assembled from the Bi2Te3 / Sb2Te3 heterojunction material of Example 1, the Bi2Te3 material of Comparative Example 1, and the Sb2Te3 material of Comparative Example 2 exhibited cycling performance in air at a current density of 1000 mA / g and a cutoff capacity of 500 mAh / g. The Bi2Te3 / Sb2Te3 electrode still showed excellent cycling performance, achieving stable cycling for 399 cycles, while the cycle lives of the Bi2Te3 and Sb2Te3 electrodes were 274 and 138 cycles, respectively.
[0078] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A bismuth telluride / antimony telluride heterojunction cathode catalyst for lithium-air batteries, characterized in that, It includes bismuth telluride / antimony telluride nanosheets, which are obtained by epitaxial growth of antimony telluride on the surface of bismuth telluride to form a lateral heterojunction.
2. The bismuth telluride / antimony telluride heterojunction cathode catalyst for lithium-air batteries as described in claim 1, characterized in that, The bismuth telluride / antimony telluride nanosheets have a diameter of 500–1200 nm and a thickness of 30–100 nm.
3. The bismuth telluride / antimony telluride heterojunction cathode catalyst for lithium-air batteries as described in claim 1, characterized in that, The molar ratio of bismuth telluride to antimony telluride is 1:(0.2~1).
4. The method for preparing the bismuth telluride / antimony telluride heterojunction cathode catalyst for lithium-air batteries according to any one of claims 1 to 3, characterized in that, Includes the following steps: The first solution is prepared by dissolving bismuth telluride, antimony source, tellurium source, first reducing agent and first surfactant in a first solvent to undergo a first solvothermal reaction.
5. The preparation method according to claim 4, characterized in that, The tellurium source is selected from one or two of sodium tellurite or tellurium powder; the antimony source is selected from one or more of antimony chloride, potassium antimony tartrate, or antimony oxide; the first reducing agent is selected from one or more of hydrazine hydrate, ammonia, sodium hydroxide, sodium borohydride, hydroxylamine, or ethylenediamine; the first surfactant is selected from one or more of ethylenediaminetetraacetic acid, hexadecyltrimethylammonium bromide, sodium dodecylbenzenesulfonate, and polyvinylpyrrolidone; the first solvent is selected from one or two of ethylene glycol or water.
6. The preparation method according to claim 4, characterized in that, The temperature of the first solvothermal reaction is 170–220°C, and the time of the first solvothermal reaction is 8–24 h; the ratio of the amount of bismuth telluride, antimony source, tellurium source, first reducing agent, first surfactant and first solvent is (0.2–1.3) mmol:(0.4–0.6) mmol:(0.6–0.9) mmol:(0.8–1) g:(0.3–0.5) g:(20–40) mL.
7. The preparation method according to claim 4, characterized in that, The bismuth telluride is obtained by dissolving a bismuth source, a tellurium source, a second reducing agent, and a second surfactant in a second solvent to undergo a second solvothermal reaction.
8. The preparation method according to claim 7, characterized in that, The bismuth source is selected from one or more of bismuth chloride, bismuth nitrate, or bismuth oxide; the tellurium source of the bismuth telluride is selected from one or two of sodium tellurite or potassium tellurite; the second reducing agent is selected from one or more of hydrazine hydrate, ammonia, sodium hydroxide, sodium borohydride, hydroxylamine, or ethylenediamine; the second surfactant is selected from one or more of ethylenediaminetetraacetic acid, hexadecyltrimethylammonium bromide, sodium dodecylbenzenesulfonate, and polyvinylpyrrolidone; and the second solvent is selected from one or two of ethylene glycol or isopropanol.
9. The preparation method according to claim 7, characterized in that, The temperature of the second solvothermal reaction is 170–220°C, and the time of the second solvothermal reaction is 8–24 h; the ratio of the amount of bismuth source, tellurium source, second reducing agent, second surfactant and second solvent is (0.5–0.7) mmol:(0.8–1) mmol:(0.4–0.6) g:(0.6–0.8) g:(20–40) mL.
10. A lithium-air battery, comprising a lithium metal anode, a cathode, and an electrolyte, characterized in that, The positive electrode comprises the bismuth telluride / antimony telluride heterojunction positive electrode catalyst for lithium-air batteries as described in any one of claims 1 to 3, or the bismuth telluride / antimony telluride heterojunction positive electrode catalyst for lithium-air batteries prepared by the preparation method described in any one of claims 4 to 9.