Sodium battery negative electrode material, preparation method thereof and sodium battery

Abstract

The application provides a sodium battery negative electrode material, a preparation method thereof and a sodium battery. The sodium battery negative electrode material MoB@MoTe2 comprises MoTe2 material and MoB material attached to the outer surface of the MoTe2 material. The MoTe2 material and the MoB material attached to the outer surface of the MoTe2 material are complementary to each other through synergistic cooperation, have the characteristics of high capacity and high conductivity, have excellent structural stability and kinetic performance, and also have good long cycle performance.

Description

Technical Field

[0001] This invention belongs to the field of sodium-ion battery technology, and relates to a sodium-ion battery anode material, its preparation method, and a sodium-ion battery. Background Technology

[0002] In recent years, with technological advancements and innovation, electronic devices, power tools, and electric vehicles have developed rapidly, making the exploration of efficient, portable, safe, and environmentally friendly energy storage materials an inevitable trend in social development. Lithium-ion batteries, due to their high energy density, have been widely commercialized, particularly in electric vehicles, portable power supplies, and electronic devices. However, lithium resources are limited and expensive, while global demand for lithium continues to increase, and their high cost restricts the large-scale application of lithium-ion batteries. Therefore, researchers have begun to focus on sodium-ion batteries. The abundance of lithium in the Earth's crust is only 0.006%, while the abundance of sodium is as high as 2.64%, far exceeding that of lithium. Sodium can be produced at a lower price, offering significant advantages in large-scale energy storage and possessing a very broad application prospect.

[0003] Sodium and lithium belong to the same group and have similar physicochemical properties. However, because the radius of sodium ions (0.102 nm) is much larger than that of lithium ions (0.076 nm), a much larger space is required for them to be successfully inserted and extracted in electrode materials. If the currently commercially available lithium-ion battery anode material, graphite (0.33 nm interlayer spacing), is directly applied to sodium ions, the insertion and extraction of sodium ions in graphite becomes extremely difficult, resulting in very limited capacity. Therefore, directly applying lithium-ion battery electrode materials to sodium-ion batteries is not feasible.

[0004] Molybdenum-based materials (such as MoO2, MoS2, MoSe2, and MoTe2) exhibit great potential in sodium-ion battery anodes due to their unique physicochemical properties, which allow them to provide high specific capacity. However, current molybdenum-based materials suffer from problems such as insufficient conductivity, poor structural stability, sluggish kinetics, and poor cycle performance, requiring further research and improvement.

[0005] Therefore, it is still necessary to find a molybdenum-based sodium anode material with high conductivity, high capacity, good stability, and excellent cycle performance. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a sodium-ion battery anode material MoB@MoTe2, its preparation method, and a sodium-ion battery. The present invention achieves high capacity and high conductivity through the synergistic cooperation and mutual complementarity of the MoTe2 material and the MoB material attached to the outer surface of the MoTe2 material. Furthermore, it exhibits excellent structural stability and kinetic performance, as well as good long-cycle performance.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a sodium-ion battery anode material, wherein the sodium-ion battery anode material MoB@MoTe2 includes a MoTe2 material and a MoB material attached to the outer surface of the MoTe2 material.

[0009] Molybdenum ditelluride (MoTe2) is a layered transition metal chalcogenide compound that has been explored as a negative electrode material for sodium-ion batteries in recent years due to its open layered structure and high theoretical specific capacity. Its sodium storage mechanism is based on the reversible insertion / extraction reaction of sodium ions between the layers. Compared to traditional hard carbon anode materials, which have smaller interlayer spacing and thus kinetically limit the transport of larger sodium ions, especially at high rates, MoTe2's high conductivity and wide interlayer spacing allow it to maintain high capacity even during high-current charge and discharge, making it suitable for fast charging applications.

[0010] However, MoTe2 faces the following key problems in sodium-ion batteries: insufficient conductivity: the semiconductor properties of MoTe2 result in low intrinsic electronic conductivity, limiting rate performance and charge transfer efficiency; poor structural stability: sodium ion radius... Greater than lithium ions The interlayer volume expansion is more significant (>250%) during repeated insertion / extraction, which can easily lead to structural collapse and pulverization of active materials; the kinetics are sluggish: the diffusion barrier of sodium ions between MoTe2 layers is high, which limits the charge and discharge rate.

[0011] While MoB possesses good electronic conductivity, potentially reducing electrode polarization and improving rate performance, pure MoB without structural optimization not only fails to provide substantial capacity but also exhibits capacity decay after multiple charge-discharge cycles. Recent research has primarily focused on improving its electrochemical performance through nanostructure design and composite material strategies. For example, embedding MoB nanoparticles into a carbon matrix can alleviate volume expansion and improve conductivity; furthermore, doping (e.g., nitrogen, sulfur) modulates the electronic structure of MoB, enhancing sodium ion adsorption kinetics. However, these improvement methods still suffer from poor interfacial compatibility, difficult preparation, and insufficient reversible capacity.

[0012] Based on this, the present invention provides a sodium electrode anode material MoB@MoTe2, comprising MoTe2 material and MoB material attached to the outer surface of MoTe2 material, forming a core-shell-like structure. The MoB material is located on the outside covering the MoTe2 material. The two materials are complementary and synergistic. As an intermetallic compound, MoB has a metal-like high conductivity (>10). 5MoB (with a density of S / m) provides a three-dimensional conductive framework for MoTe2, significantly reducing charge transfer impedance and compensating for the sluggish kinetics common in sodium-ion batteries. Simultaneously, MoTe2, as the active host, contributes high specific capacity, avoiding the capacity dilution effect of carbon-based composites. Its three-dimensional rigid structure serves as a conductive network, enhancing the overall electron transport capability of the composite material. Furthermore, the rigid three-dimensional framework of MoB effectively suppresses interlayer expansion of MoTe2 during sodium ion intercalation, and its chemical inertness reduces side reactions between the electrolyte and Te, stabilizing the SEI film. Further, the combination of MoTe2-dominated intercalation reaction and adsorption / interfacial sodium storage at MoB surface defect sites broadens sodium ion transport channels, improving the rate performance and cycle reversibility of the composite material, optimizing the sodium storage mechanism, and enhancing kinetic performance. This results in sodium-ion battery anode materials exhibiting high conductivity, high capacity, excellent kinetic performance, and long cycle life.

[0013] Furthermore, the MoB@MoTe2 material in this application is not a simple physical mixture of MoTe2 and MoB, but a heterostructure formed by MoB growing in situ on the surface of MoTe2. Simple physical mixing does not produce a new structure, so it does not have the excellent properties of the MoB@MoTe2 material in this application.

[0014] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The technical objectives and beneficial effects of the present invention can be better achieved and realized through the following preferred technical solutions.

[0015] Preferably, the morphology of the MoTe2 material is a block structure formed by stacking multiple layers of sheet-like structures, and the block structure is a micron-scale structure.

[0016] Preferably, the MoB material is attached to the outer surface of the block structure.

[0017] Preferably, the morphology of the MoB material is a needle-like structure, and the needle-like structure is a nanoscale structure.

[0018] Preferably, the needle-like structure is grown in situ on the outer surface of the MoTe2 material.

[0019] In this invention, MoB material with a nanoscale needle-like structure forms a three-dimensional rigid structure, grown in situ on the outer surface of a micron-scale bulk MoTe2 material. This special structure has the following characteristics: 1. It effectively buffers the volume change of MoTe2, improving the stability of the structure; 2. MoB grows directly on the MoTe2 sheets, exhibiting strong interfacial bonding and reducing interfacial resistance; 3. The MoB nanoneedles covering the layered MoTe2 sheets transform the original two-dimensional sheet structure into a three-dimensional structure, greatly increasing the specific surface area of ​​the material and exposing more active sites.

[0020] Preferably, the median particle size D50 of the sodium-ion battery anode material is 5μm to 15μm, such as 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm or 15μm, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0021] In a second aspect, the present invention provides a method for preparing a sodium-ion battery anode material as described in the first aspect, the method comprising the following steps:

[0022] By mixing B source, Mo source and Te source, a hybrid material is obtained;

[0023] The mixed materials are calcined in a vacuum environment or under a protective atmosphere to obtain the sodium-ion battery anode material.

[0024] In the technical solution of this invention, the calcination process of the mixed material of B source, Mo source and Te source is carried out in a vacuum environment or protective atmosphere to obtain MoTe2 material and MoB material attached to the outer surface of MoTe2 material, forming a special heterojunction structure, thereby exerting the synergistic effect of MoTe2 material and MoB material.

[0025] For the purposes of this invention, simply physically mixing MoTe2 and MoB materials cannot form the corresponding structure, and therefore cannot solve the corresponding problem.

[0026] It is understood that the protective atmosphere in this invention is a gaseous atmosphere environment that does not affect the reaction, such as including but not limited to nitrogen atmosphere and / or inert gas atmosphere, wherein the inert gas includes but is not limited to argon and / or helium.

[0027] Preferably, the molar ratio of B in the B source, Mo in the Mo source, and Te in the Te source is 1:(1~4):(1~4), such as 1:1:1, 1:2:1, 1:3:1, 1:4:1, 1:1:2, 1:2:2, 1:3:2, 1:4:2, 1:1:3, 1:2:3, 1:3:3, 1:4:3, 1:1:4, 1:2:4, 1:3:4, or 1:4:4, etc., but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0028] In the preparation of sodium-ion battery anode materials, a suitable raw material ratio is crucial for obtaining products with stable structure and excellent performance. This invention controls the molar ratio of B in the B source, Mo in the Mo source, and Te in the Te source to 1:(1-4):(1-4). This ensures that the proportions of each raw material are appropriate, resulting in structurally stable and homogeneous MoB and MoTe2. If B is excessive, it will cause the MoB needle-like structure to agglomerate, leading to the breakage of the conductive network; if B is insufficient, it will lead to incomplete MoB coverage, resulting in the failure of mechanical support; if Mo is excessive, it will lead to the formation of impurities such as Mo2B and Mo3Te4; if Mo is insufficient, it will lead to the formation of free Te, B2Te3, or other impurities; if Te is excessive, it will lead to the production of free Te, MoTe3, or other impurities; if Te is insufficient, it will lead to the formation of tellurium-depleted phases such as Mo3Te4 and MoB2.

[0029] Furthermore, this application does not impose any specific limitations on the types of substances used for the B source, Mo source, and Te source. Without departing from the technical concept of this invention, any known substance that can be used to prepare MoTe2 materials and MoB materials is applicable in principle.

[0030] For example, the B source includes, but is not limited to, boron powder; the Mo source includes, but is not limited to, molybdenum powder; and the Te source includes, but is not limited to, tellurium powder.

[0031] Preferably, the B source, Mo source, and Te source are first dried before being mixed.

[0032] It is understood that in this invention, the B source, Mo source and Te source are first dried to avoid the influence of moisture during the preparation process. Furthermore, this invention does not impose any special limitations on the specific drying method. Conventional methods for drying materials are applicable to this invention, such as vacuum drying and / or forced air drying.

[0033] Furthermore, the drying temperature can be 70℃ to 90℃, such as 70℃, 80℃ or 90℃, and the drying time can be 6h to 24h, such as 6h, 8h, 10h, 12h, 15h, 18h, 20h or 24h, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0034] Preferably, the heating rate of the calcination is 3℃ / min to 5℃ / min, such as 3℃ / min, 4℃ / min or 5℃ / min, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0035] Preferably, the calcination holding temperature is 800℃~1000℃, such as 800℃, 850℃, 900℃, 950℃ or 1000℃, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0036] Preferably, the calcination holding time is 12h to 24h, such as 12h, 15h, 18h, 20h or 24h, but it is not limited to the listed values. Other unlisted values ​​within this range are also applicable.

[0037] In the vacuum calcination process of this invention, the preferred heating rate is 3℃ / min to 5℃ / min and / or the holding temperature is 800℃ to 1000℃ and / or the holding time is 12h to 24h. The vacuum calcination time and temperature should adhere to the above ranges. If the calcination temperature is too low, MoB and MoTe2 will not be successfully generated, and the target product cannot be obtained. If the calcination temperature is too high, it will lead to the decomposition and structural destruction of MoTe2, and will also generate impurities such as Mo2B and MoB2. If the calcination time is too short, the reaction will be incomplete, leaving many unreacted raw materials. If the calcination time is too long, it will lead to over-sintering and coarsening; the MoTe2 lamellars may become thicker and wider, and the MoB needles may become coarser.

[0038] It should be noted that the present invention does not impose special limitations on the reaction vessel during the calcination process. Any vessel that can withstand the calcination temperature and will not affect the material synthesis is applicable to the present invention. For example, the material of the reaction vessel can be quartz, silicon carbide, or ceramic materials such as zirconium oxide and alumina, or metal or alloy materials such as zirconium and tungsten.

[0039] Thirdly, the present invention also provides a sodium-ion battery, the sodium-ion battery comprising the sodium-ion anode material as described in the first aspect or the sodium-ion anode material prepared by the preparation method described in the second aspect.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] This invention provides a sodium electrode anode material MoB@MoTe2, comprising MoTe2 material and MoB material attached to the outer surface of MoTe2 material, forming a core-shell-like structure. The MoB material covers the MoTe2 material on the outside, and the two materials complement and synergistically cooperate. As an intermetallic compound, MoB possesses high metal-like conductivity (>10). 5MoB (with a density of S / m) provides a three-dimensional conductive framework for MoTe2, significantly reducing charge transfer impedance and compensating for the sluggish kinetics common in sodium-ion batteries. Simultaneously, MoTe2, as the active host, contributes high specific capacity, avoiding the capacity dilution effect of carbon-based composites. Its three-dimensional rigid structure serves as a conductive network, enhancing the overall electron transport capability of the composite material. Furthermore, the rigid three-dimensional framework of MoB effectively suppresses interlayer expansion of MoTe2 during sodium ion intercalation, and its chemical inertness reduces side reactions between the electrolyte and Te, stabilizing the SEI film. Further, the combination of MoTe2-dominated intercalation reaction and adsorption / interfacial sodium storage at MoB surface defect sites broadens sodium ion transport channels, improving the rate performance and cycle reversibility of the composite material, optimizing the sodium storage mechanism, and enhancing kinetic performance. This results in sodium-ion battery anode materials exhibiting high conductivity, high capacity, excellent kinetic performance, and long cycle life. Attached Figure Description

[0042] Figure 1 The image shows the XRD pattern of the sodium-ion battery anode material in Example 1.

[0043] Figure 2 and Figure 3 This is a SEM image of the sodium-ion battery anode material from Example 1.

[0044] Figure 4 The cycling curve of the sodium battery provided in Example 1 is shown.

[0045] Figure 5 The cycling curve of the sodium battery provided in Example 2.

[0046] Figure 6 The cycling curve of the sodium battery provided in Example 3 is shown.

[0047] Figure 7 The cycling curve of the sodium battery provided in Example 4 is shown.

[0048] Figure 8 The cycling curve of the sodium battery provided in Example 5 is shown.

[0049] Figure 9 The cycling curve of the sodium battery provided in Example 6 is shown.

[0050] Figure 10 The cycling curve of the sodium battery provided in Example 7 is shown.

[0051] Figure 11 The cycling curve of the sodium battery provided in Example 8.

[0052] Figure 12 The cycling curve of the sodium battery provided in Example 9.

[0053] Figure 13 The cycling curve of the sodium battery provided in Example 10.

[0054] Figure 14 The cycling curve of the sodium battery provided in Example 11.

[0055] Figure 15 Cycle curve of the sodium battery provided in Example 12.

[0056] Figure 16 The XRD pattern of the sodium electrode anode material provided for Comparative Example 1.

[0057] Figure 17 SEM image of the sodium electrode anode material provided for Comparative Example 1.

[0058] Figure 18 Cycle curve of sodium battery provided for Comparative Example 1.

[0059] Figure 19 The XRD pattern of the sodium electrode anode material provided for Comparative Example 2.

[0060] Figure 20 SEM image of the sodium electrode anode material provided for Comparative Example 2.

[0061] Figure 21 Cycle curve of sodium battery provided for Comparative Example 2.

[0062] Figure 22 Cycle curve of sodium battery provided for Comparative Example 3.

[0063] Figure 23 Cycle curve of sodium battery provided for Comparative Example 4. Detailed Implementation

[0064] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention.

[0065] Unless otherwise defined, 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 application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this application; the terms “comprising” and “having” and any variations thereof in this application are intended to cover non-exclusive inclusion.

[0066] In the description of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary or secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0067] Example 1

[0068] This embodiment provides a sodium-ion battery anode material, which includes a MoTe2 material with a micron-scale bulk structure formed by stacking multiple sheet-like structures, and a nano-scale MoB material with a needle-like structure attached to the outer surface of the bulk structure of the MoTe2 material.

[0069] The preparation method of the sodium-ion battery anode material is as follows:

[0070] S1. Weigh 0.108g (0.01mol) boron powder, 1.919g (0.02mol) molybdenum powder and 2.552g (0.02mol) tellurium powder, dry them in a vacuum oven at 80℃ for 12 hours, and then stir to mix the three together to obtain a mixed material.

[0071] S2. Place the uniformly mixed material into a silicon carbide (SiC) container and evacuate the container.

[0072] S3. Place the vacuum-sealed silicon carbide container in a muffle furnace and heat it to 800°C at a heating rate of 5°C / min for 24 hours. After the reaction is complete and it cools naturally, the sodium electrode anode material is obtained.

[0073] Figure 1 The XRD pattern of the sodium-ion battery anode material of Example 1 is shown. Figure 1 As can be seen, the sodium-ion battery anode material (MoB@MoTe2) obtained in this embodiment has only two phases, MoB and MoTe2, which corresponds to the standard cards (PDF#51-0940 and PDF#71-2157) of MoB and MoTe2, and does not contain other impurities.

[0074] Figure 2 and Figure 3 SEM images of the sodium-ion battery anode material of Example 1 are shown. Figure 2 and Figure 3 As can be seen, the sodium electrode material MoB@MoTe2 in Example 1 is composed of sheet-like MoTe2 and needle-like MoB, with the needle-like MoB covering the sheet-like MoTe2.

[0075] When the obtained sodium-ion battery anode material is used as the anode of a sodium-ion battery, its initial capacity is 393.76 mAh / g. After 100 charge-discharge cycles at a current density of 0.1 A / g, the capacity still remains at 345.26 mAh / g. The specific cycle performance is shown in the figure below. Figure 4 As shown.

[0076] Example 2

[0077] This embodiment provides a sodium-ion battery anode material, which includes a MoTe2 material with a micron-scale bulk structure formed by stacking multiple sheet-like structures, and a nano-scale MoB material with a needle-like structure attached to the outer surface of the bulk structure of the MoTe2 material.

[0078] The preparation method of the sodium-ion battery anode material is as follows:

[0079] S1. Weigh 0.108g (0.01mol) boron powder, 1.919g (0.02mol) molybdenum powder and 2.552g (0.02mol) tellurium powder, dry them in a vacuum oven at 80℃ for 12 hours, and then stir to mix the three together to obtain a mixed material.

[0080] S2. Place the uniformly mixed material into a zirconium oxide (ZrO2) container and vacuum the container.

[0081] S3. Place the vacuum-sealed silicon carbide container in a muffle furnace and heat it to 900°C at a heating rate of 5°C / min for 24 hours. After the reaction is complete and it cools naturally, the sodium electrode anode material is obtained.

[0082] When the obtained sodium-ion battery anode material is used as the anode of a sodium-ion battery, its initial capacity is 383.13 mAh / g. After 100 charge-discharge cycles at a current density of 0.1 A / g, the capacity still remains at 337.22 mAh / g. The specific cycle performance is shown in the figure below. Figure 5 As shown.

[0083] Example 3

[0084] This embodiment provides a sodium-ion battery anode material, which includes a MoTe2 material with a micron-scale bulk structure formed by stacking multiple sheet-like structures, and a nano-scale MoB material with a needle-like structure attached to the outer surface of the bulk structure of the MoTe2 material.

[0085] The preparation method of the sodium-ion battery anode material is as follows:

[0086] S1. Weigh 0.108g (0.01mol) boron powder, 1.919g (0.02mol) molybdenum powder and 2.552g (0.02mol) tellurium powder, dry them in a vacuum oven at 80℃ for 12 hours, and then stir to mix the three together to obtain a mixed material.

[0087] S2. Place the well-mixed material into an alumina (Al2O3) container and vacuum the container.

[0088] S3. Place the vacuum-sealed silicon carbide container in a muffle furnace and heat it to 1000°C at a heating rate of 3°C / min for 12 hours. After the reaction is complete and it cools naturally, the sodium-ion battery anode material is obtained.

[0089] When the obtained sodium-ion battery anode material is used as the anode of a sodium-ion battery, its initial capacity is 374.57 mAh / g. After 100 charge-discharge cycles at a current density of 0.1 A / g, the capacity still remains at 310.6 mAh / g. The specific cycle performance is shown in the figure below. Figure 6 As shown.

[0090] Example 4

[0091] This embodiment provides a sodium-ion battery anode material, which includes a MoTe2 material with a micron-scale bulk structure formed by stacking multiple sheet-like structures, and a nano-scale MoB material with a needle-like structure attached to the outer surface of the bulk structure of the MoTe2 material.

[0092] The preparation method of the sodium-ion battery anode material is as follows:

[0093] S1. Weigh 0.108g (0.01mol) boron powder, 3.838g (0.04mol) molybdenum powder and 5.104g (0.04mol) tellurium powder, dry them in a vacuum oven at 80℃ for 12 hours, and then stir to mix the three materials evenly to obtain a mixed material.

[0094] S2. Place the well-mixed material into a silicon carbide (SiC) container;

[0095] S3. Place the silicon carbide container protected by a nitrogen atmosphere in a muffle furnace, and calcine it to 1000°C at a heating rate of 5°C / min for 24 hours in a nitrogen atmosphere. After the reaction is completed and it is naturally cooled, the sodium electrode anode material is obtained.

[0096] When the obtained sodium-ion battery anode material is used as the anode of a sodium-ion battery, its initial capacity is 348.87 mAh / g. After 100 charge-discharge cycles at a current density of 0.1 A / g, the capacity still remains at 289.12 mAh / g. The specific cycle performance is shown in the figure below. Figure 7 As shown.

[0097] Example 5

[0098] This embodiment provides a sodium-ion battery anode material, which includes a MoTe2 material with a micron-scale bulk structure formed by stacking multiple sheet-like structures, and a nano-scale MoB material with a needle-like structure attached to the outer surface of the bulk structure of the MoTe2 material.

[0099] The preparation method of the sodium-ion battery anode material is as follows:

[0100] S1. Weigh 0.216g (10.8, 0.02mol) boron powder, 1.919g (0.02mol) molybdenum powder and 2.552g (0.02mol) tellurium powder, dry them in a vacuum oven at 80℃ for 12 hours, and then stir to mix the three together to obtain a mixed material.

[0101] S2. Place the well-mixed material in a zirconium (Zr) container and purge the container with nitrogen gas for protection.

[0102] S3. Place the silicon carbide container protected by a mixed atmosphere of nitrogen and argon in a muffle furnace, and calcine it to 800°C at a heating rate of 5°C / min in a nitrogen atmosphere for 24 hours. After the reaction is completed and it cools naturally, the sodium electrode anode material is obtained.

[0103] When the obtained sodium-ion battery anode material is used as the anode of a sodium-ion battery, its initial capacity is 365.3 mAh / g. After 100 charge-discharge cycles at a current density of 0.1 A / g, the capacity still remains at 272.58 mAh / g. The specific cycle performance is shown in the figure below. Figure 8 As shown.

[0104] Example 6

[0105] This embodiment provides a sodium-ion battery anode material, which includes a MoTe2 material with a micron-scale bulk structure formed by stacking multiple sheet-like structures, and a nano-scale MoB material with a needle-like structure attached to the outer surface of the bulk structure of the MoTe2 material.

[0106] The preparation method of the sodium-ion battery anode material is as follows:

[0107] S1. Weigh 0.108g (0.01mol) boron powder, 0.479g (0.005mol) molybdenum powder and 2.552g (0.02mol) tellurium powder, dry them in a vacuum oven at 80℃ for 12 hours, and then stir to mix the three together to obtain a mixed material.

[0108] S2. Place the uniformly mixed material into a silicon carbide (SiC) container and evacuate the container.

[0109] S3. Place the vacuum-sealed silicon carbide container in a muffle furnace and heat it to 800°C at a heating rate of 5°C / min for 24 hours. After the reaction is complete and it cools naturally, the sodium electrode anode material is obtained.

[0110] When the obtained sodium-ion battery anode material was used as the anode of a sodium-ion battery, its initial capacity was 177.77 mAh / g. After 100 charge-discharge cycles at a current density of 0.1 A / g, the capacity was 92.65 mAh / g. The specific cycle performance is shown in the figure below. Figure 9 As shown.

[0111] Example 7

[0112] This embodiment provides a sodium-ion battery anode material, which includes a MoTe2 material with a micron-scale bulk structure formed by stacking multiple sheet-like structures, and a nano-scale MoB material with a needle-like structure attached to the outer surface of the bulk structure of the MoTe2 material.

[0113] The preparation method of the sodium-ion battery anode material is as follows:

[0114] S1. Weigh 0.108g (0.01mol) boron powder, 4.795g (0.05mol) molybdenum powder and 2.552g (0.02mol) tellurium powder, dry them in a vacuum oven at 80℃ for 12 hours, and then stir to mix the three materials evenly to obtain a mixed material.

[0115] S2. Place the uniformly mixed material into a silicon carbide (SiC) container and evacuate the container.

[0116] S3. Place the vacuum-sealed silicon carbide container in a muffle furnace and heat it to 800°C at a heating rate of 5°C / min for 24 hours. After the reaction is complete and it cools naturally, the sodium electrode anode material is obtained.

[0117] When the obtained sodium-ion battery anode material was used as the anode of a sodium-ion battery, its initial capacity was 316.77 mAh / g. After 100 charge-discharge cycles at a current density of 0.1 A / g, the capacity was 141.47 mAh / g. The specific cycle performance is shown in the figure below. Figure 10 As shown.

[0118] Example 8

[0119] This embodiment provides a sodium-ion battery anode material, which includes a MoTe2 material with a micron-scale bulk structure formed by stacking multiple sheet-like structures, and a nano-scale MoB material with a needle-like structure attached to the outer surface of the bulk structure of the MoTe2 material.

[0120] The preparation method of the sodium-ion battery anode material is as follows:

[0121] S1. Weigh 0.108g (0.01mol) boron powder, 1.919g (0.02mol) molybdenum powder and 0.638g (0.005mol) tellurium powder, dry them in a vacuum oven at 80℃ for 12 hours, and then stir to mix the three together to obtain a mixed material.

[0122] S2. Place the uniformly mixed material into a silicon carbide (SiC) container and evacuate the container.

[0123] S3. Place the vacuum-sealed silicon carbide container in a muffle furnace and heat it to 800°C at a heating rate of 5°C / min for 24 hours. After the reaction is complete and it cools naturally, the sodium electrode anode material is obtained.

[0124] When the obtained sodium-ion battery anode material was used as the anode of a sodium-ion battery, its initial capacity was 264.13 mAh / g. After 100 charge-discharge cycles at a current density of 0.1 A / g, the capacity was 161.79 mAh / g. The specific cycle performance is shown in the figure below. Figure 11 As shown.

[0125] Example 9

[0126] This embodiment provides a sodium-ion battery anode material, which includes a MoTe2 material with a micron-scale bulk structure formed by stacking multiple sheet-like structures, and a nano-scale MoB material with a needle-like structure attached to the outer surface of the bulk structure of the MoTe2 material.

[0127] The preparation method of the sodium-ion battery anode material is as follows:

[0128] S1. Weigh 0.108g (0.01mol) boron powder, 1.919g (0.02mol) molybdenum powder and 6.38g (0.05mol) tellurium powder, dry them in a vacuum oven at 80℃ for 12 hours, and then stir to mix the three together to obtain a mixed material.

[0129] S2. Place the uniformly mixed material into a silicon carbide (SiC) container and evacuate the container.

[0130] S3. Place the vacuum-sealed silicon carbide container in a muffle furnace and heat it to 800°C at a heating rate of 5°C / min for 24 hours. After the reaction is complete and it cools naturally, the sodium electrode anode material is obtained.

[0131] When the obtained sodium-ion battery anode material was used as the anode of a sodium-ion battery, its initial capacity was 264.96 mAh / g. After 100 charge-discharge cycles at a current density of 0.1 A / g, the capacity was 121.79 mAh / g. The specific cycle performance is shown in the figure below. Figure 12 As shown.

[0132] Example 10

[0133] This embodiment provides a sodium-ion battery anode material, which includes a MoTe2 material with a micron-scale bulk structure formed by stacking multiple sheet-like structures, and a nano-scale MoB material with a needle-like structure attached to the outer surface of the bulk structure of the MoTe2 material.

[0134] The preparation method of the sodium-ion battery anode material is as follows:

[0135] S1. Weigh 0.108g (0.01mol) boron powder, 1.919g (0.02mol) molybdenum powder and 2.552g (0.02mol) tellurium powder, dry them in a vacuum oven at 80℃ for 12 hours, and then stir to mix the three together to obtain a mixed material.

[0136] S2. Place the uniformly mixed material into a silicon carbide (SiC) container and evacuate the container.

[0137] S3. Place the vacuum-sealed silicon carbide container in a muffle furnace and heat it to 800°C at a heating rate of 10°C / min for 24 hours. After the reaction is complete and it cools naturally, the sodium electrode anode material is obtained.

[0138] When the obtained sodium-ion battery anode material was used as the anode of a sodium-ion battery, its initial capacity was 381.93 mAh / g. After 100 charge-discharge cycles at a current density of 0.1 A / g, the capacity was 335.5 mAh / g. The specific cycle performance is shown in the figure below. Figure 13 As shown.

[0139] Example 11

[0140] This embodiment provides a sodium-ion battery anode material, which includes a MoTe2 material with a micron-scale bulk structure formed by stacking multiple sheet-like structures, and a nano-scale MoB material with a needle-like structure attached to the outer surface of the bulk structure of the MoTe2 material.

[0141] The preparation method of the sodium-ion battery anode material is as follows:

[0142] S1. Weigh 0.108g (0.01mol) boron powder, 1.919g (0.02mol) molybdenum powder and 2.552g (0.02mol) tellurium powder, dry them in a vacuum oven at 80℃ for 12 hours, and then stir to mix the three together to obtain a mixed material.

[0143] S2. Place the uniformly mixed material into a silicon carbide (SiC) container and evacuate the container.

[0144] S3. Place the vacuum-sealed silicon carbide container in a muffle furnace and heat it to 700°C at a heating rate of 5°C / min for 24 hours. After the reaction is complete and it cools naturally, the sodium electrode anode material is obtained.

[0145] When the obtained sodium-ion battery anode material was used as the anode of a sodium-ion battery, its initial capacity was 325.06 mAh / g. After 100 charge-discharge cycles at a current density of 0.1 A / g, the capacity was 306.13 mAh / g. The specific cycle performance is shown in the figure below. Figure 14 As shown.

[0146] Example 12

[0147] This embodiment provides a sodium-ion battery anode material, which includes a MoTe2 material with a micron-scale bulk structure formed by stacking multiple sheet-like structures, and a nano-scale MoB material with a needle-like structure attached to the outer surface of the bulk structure of the MoTe2 material.

[0148] The preparation method of the sodium-ion battery anode material is as follows:

[0149] S1. Weigh 0.108g (0.01mol) boron powder, 1.919g (0.02mol) molybdenum powder and 2.552g (0.02mol) tellurium powder, dry them in a vacuum oven at 80℃ for 12 hours, and then stir to mix the three together to obtain a mixed material.

[0150] S2. Place the uniformly mixed material into a silicon carbide (SiC) container and evacuate the container.

[0151] S3. Place the vacuum-sealed silicon carbide container in a muffle furnace and heat it to 1100°C at a heating rate of 5°C / min for 24 hours. After the reaction is complete and it cools naturally, the sodium-ion battery anode material is obtained.

[0152] When the obtained sodium-ion battery anode material was used as the anode of a sodium-ion battery, its initial capacity was 356.57 mAh / g. After 100 charge-discharge cycles at a current density of 0.1 A / g, the capacity was 290.63 mAh / g. The specific cycle performance is shown in the figure below. Figure 15 As shown.

[0153] Comparative Example 1

[0154] This comparative example provides a sodium electrode anode material, MoB.

[0155] The preparation method of the sodium-ion battery anode material is as follows:

[0156] S1. Weigh 0.108g (0.01mol) boron powder and 1.919g (0.02mol) molybdenum powder, dry them in a vacuum oven at 80℃ for 12 hours, and then stir to mix them evenly to obtain a mixed material.

[0157] S2. Place the uniformly mixed material into a silicon carbide (SiC) container and evacuate the container.

[0158] S3. Place the vacuum-sealed silicon carbide container in a muffle furnace and heat it to 800°C at a heating rate of 5°C / min for 24 hours. After the reaction is complete and it cools naturally, the sodium electrode anode material is obtained.

[0159] Figure 16 The XRD pattern of the sodium-ion battery anode material provided in Comparative Example 1 is shown. Figure 16 It can be seen that the MoB prepared in Comparative Example 1 corresponds to the standard MoB card (PDF#51-0940) and does not contain any other impurities.

[0160] Figure 17 SEM images of the sodium-ion battery anode material provided in Comparative Example 1 are shown. Figure 17 It can be seen that the MoB prepared in Comparative Example 1 is a micron-sized particulate material.

[0161] When the obtained sodium-ion battery anode material was used as the anode of a sodium-ion battery, its initial capacity was 105.33 mAh / g. After 100 charge-discharge cycles at a current density of 0.1 A / g, the capacity was 93.7 mAh / g. The specific cycle performance is shown in the figure below. Figure 18 As shown.

[0162] Comparative Example 2

[0163] This comparative example provides a sodium electrode anode material, MoTe2.

[0164] The preparation method of the sodium-ion battery anode material is as follows:

[0165] S1, 0.959 g (0.01 mol) of molybdenum powder and 2.552 g (0.02 mol) of tellurium powder were dried in a vacuum oven at 80°C for 12 hours, and then stirred to mix them evenly to obtain a mixed material.

[0166] S2. Place the uniformly mixed material into a silicon carbide (SiC) container and evacuate the container.

[0167] S3. Place the vacuum-sealed silicon carbide container in a muffle furnace and heat it to 800°C at a heating rate of 5°C / min for 24 hours. After the reaction is complete and it cools naturally, the sodium electrode anode material is obtained.

[0168] Figure 19 The XRD pattern of the sodium-ion battery anode material provided in Comparative Example 2 is shown. Figure 19 It can be seen that the MoTe2 prepared in Comparative Example 2 corresponds to the standard card of MoTe2 (PDF#71-2157) and does not contain other impurities.

[0169] Figure 20 SEM images of the sodium-ion battery anode material provided in Comparative Example 2 are shown. Figure 20 It can be seen that the MoTe2 prepared in Comparative Example 1 is a micron-sized sheet-like material.

[0170] When the obtained sodium-ion battery anode material was used as the anode of a sodium-ion battery, its initial capacity was 359.91 mAh / g. After 100 charge-discharge cycles at a current density of 0.1 A / g, the capacity was 229.4 mAh / g. The specific cycle performance is shown in the figure below. Figure 21 As shown.

[0171] Comparative Example 3

[0172] This comparative example provides a sodium-electric anode material, which is a physical mixture of MoTe2 and MoB materials.

[0173] The preparation method of the sodium-ion battery anode material is as follows:

[0174] Weigh 1.068g (0.01mol) of MoB from Comparative Example 1 and 3.512g (0.01mol) of MoTe2 from Comparative Example 2, place them in a mortar and grind for 2 hours to mix them evenly, and obtain the mixed material MoB / MoTe2.

[0175] When the obtained sodium-ion battery anode material was used as the anode of a sodium-ion battery, its initial capacity was 288.69 mAh / g. After 100 charge-discharge cycles at a current density of 0.1 A / g, the capacity was 226.65 mAh / g. The specific cycle performance is shown in the figure below. Figure 22As shown.

[0176] Comparative Example 4

[0177] This comparative example provides a sodium electrode anode material.

[0178] The preparation method of the sodium-ion battery anode material is as follows:

[0179] S1. Weigh 0.108g (0.01mol) boron powder, 1.919g (0.02mol) molybdenum powder and 2.552g (0.02mol) tellurium powder, dry them in a vacuum oven at 80℃ for 12 hours, and then stir to mix the three together to obtain a mixed material.

[0180] S2. Place the well-mixed material into a silicon carbide (SiC) container.

[0181] S3. Place the silicon carbide container in a muffle furnace and heat it to 800°C at a heating rate of 5°C / min for 24 hours. After the reaction is complete and it cools naturally, the sodium-ion battery anode material is obtained.

[0182] When the obtained sodium-ion battery anode material was used as the anode of a sodium-ion battery, its initial capacity was 236.87 mAh / g. After 100 charge-discharge cycles at a current density of 0.1 A / g, the capacity was 52.84 mAh / g. The specific cycle performance is shown in the figure below. Figure 23 As shown.

[0183] [Battery Fabrication and Performance Testing]

[0184] I. Battery Manufacturing

[0185] The sodium-ion battery anode material obtained in the above examples and comparative examples was applied to the anode sheet. 0.8g of the obtained anode material was weighed, and 0.1g of carbon black and 0.1g of carboxymethyl cellulose (CMC) dissolved in deionized water were added. After homogenization, the mixture was coated onto copper foil to form the anode sheet.

[0186] Counter electrode: Sodium metal sheet.

[0187] Diaphragm: Glass fiber.

[0188] Electrolyte: 1 mol / L NaPF6 dissolved in solvent system G2 (diethylene glycol dimethyl ether).

[0189] In a glove box under an argon atmosphere, the above-mentioned counter electrode, negative electrode and separator are assembled, and then the electrolyte is injected to obtain a 2032 button cell.

[0190] II Performance Testing

[0191] Battery cycle performance test: The sodium-ion button batteries of the examples and comparative examples were subjected to charge-discharge cycle tests at a current density of 0.1 A / g. After 100 cycles, their initial capacity and capacity after 100 cycles were obtained.

[0192] Figure 4 The cycling curve of the sodium battery provided in Example 1 is shown.

[0193] Figure 5 The cycling curve of the sodium battery provided in Example 2 is shown.

[0194] Figure 6 The cycling curve of the sodium battery provided in Example 3 is shown.

[0195] Figure 7 The cycling curve of the sodium battery provided in Example 4 is shown.

[0196] Figure 8 The cycling curve of the sodium battery provided in Example 5 is shown.

[0197] Figure 9 The cycling curve of the sodium battery provided in Example 6 is shown.

[0198] Figure 10 The cycling curve of the sodium battery provided in Example 7 is shown.

[0199] Figure 11 The cycling curve of the sodium battery provided in Example 8 is shown.

[0200] Figure 12 The cycling curve of the sodium battery provided in Example 9 is shown.

[0201] Figure 13 The cycling curve of the sodium battery provided in Example 10 is shown.

[0202] Figure 14 The cycling curve of the sodium battery provided in Example 11 is shown.

[0203] Figure 15 The cycling curve of the sodium battery provided in Example 12 is shown.

[0204] Figure 18 The cycling curve of the sodium battery provided in Comparative Example 1 is shown.

[0205] Figure 21 Cycle curves of the sodium battery provided in Comparative Example 2 are shown.

[0206] Figure 22 Cyclic curves of the sodium battery provided in Comparative Example 3 are shown.

[0207] Figure 23 Cycle curves of the sodium-ion battery provided in Comparative Example 4 are shown.

[0208] From the above Figures 4 to 15 , Figure 18 ,as well as Figures 21 to 23 The comparison shows that the MoB@MoTe2 material with a special morphology provided by the present invention has excellent cycling performance, while the cycling performance of MoB material alone or MoTe2 material alone deteriorates significantly.

[0209] The test results are shown in Table 1.

[0210] Table 1

[0211]

[0212] From Table 1 and Figure 1-23 We can conclude that:

[0213] The sodium-ion battery anode material with a special heterojunction structure, consisting of MoTe2 material and MoB material attached to the outer surface of the MoTe2 material, exhibits excellent electrochemical performance. Furthermore, by controlling the raw material ratio, calcination environment, and calcination parameters, the capacity and cycle performance of the sodium-ion battery are further improved.

[0214] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A sodium-ion battery anode material, characterized in that, The sodium electrode anode material includes MoTe2 material and MoB material attached to the outer surface of the MoTe2 material.

2. The sodium-ion battery anode material according to claim 1, characterized in that, The morphology of the MoTe2 material is a block structure formed by stacking multiple layers of sheet-like structures, and the block structure is a micron-scale structure; Preferably, the MoB material is attached to the outer surface of the block structure.

3. The sodium-ion battery anode material according to claim 1 or 2, characterized in that, The morphology of the MoB material is needle-like, and the needle-like structure is a nanoscale structure; Preferably, the needle-like structure is grown in situ on the outer surface of the MoTe2 material.

4. The sodium-ion battery anode material according to claim 1, characterized in that, The median particle size D50 of the sodium-ion battery anode material is 5 μm to 15 μm.

5. A method for preparing a sodium-ion battery anode material as described in any one of claims 1-4, characterized in that, The preparation method includes the following steps: By mixing B source, Mo source and Te source, a hybrid material is obtained; The mixed materials are calcined in a vacuum environment or under a protective atmosphere to obtain the sodium-ion battery anode material.

6. The preparation method according to claim 5, characterized in that, The molar ratio of B in the B source, Mo in the Mo source, and Te in the Te source is 1:(1~4):(1~4).

7. The preparation method according to claim 5, characterized in that, First, the B source, Mo source, and Te source are dried, and then they are mixed.

8. The preparation method according to claim 5, characterized in that, The heating rate for calcination is 3℃ / min to 5℃ / min.

9. The preparation method according to claim 5 or 8, characterized in that, The calcination holding temperature is 800℃~1000℃; the calcination holding time is 12h~24h.

10. A sodium-ion battery, characterized in that, The sodium-ion battery includes the sodium-ion anode material as described in any one of claims 1-4 or the sodium-ion anode material prepared by the preparation method as described in any one of claims 5-9.

Images