Sodium-ion battery negative electrode material and preparation method and application thereof

Abstract

The application relates to the technical field of batteries, in particular to a sodium ion battery negative electrode material and a preparation method and application thereof, and the sodium ion battery negative electrode material comprises a compound shown in formula 1: TiNb 24‑x M x O 62 Formula 1 wherein M comprises at least five of Re, Mo, W, V, Cr, Cu, Ni, Fe, Co, Cu, Zn, Mn, Sn, Bi, K, Mg, Al, Li, Rb, Cs, Ru, Rh, Pd, Ag, In, Ir and Pb; and x is 0.8-1.6. The sodium ion battery negative electrode material has high specific capacity, high rate characteristics and excellent cycle performance.

Description

Technical Field

[0001] This application relates to the field of sodium-ion battery technology, specifically to sodium-ion battery anode materials, their preparation methods and applications, and more specifically to sodium-ion battery anode materials, their preparation methods, sodium-ion batteries and electrical devices. Background Technology

[0002] Titanium niobate (TiNb) 24 O 62 Sodium niobate (TiNb) is considered an ideal anode material for lithium-ion batteries due to its excellent performance and high safety. Its high operating potential effectively prevents the formation of lithium dendrites. However, its low electronic and ionic conductivity limits its further development in electrochemical energy storage applications, especially for sodium ions, which have a larger ionic radius and greater diffusion resistance, further reducing their electronic and ionic conductivity. Nevertheless, due to the widespread availability and lack of geographical limitations of sodium resources, and the similar electrochemical storage characteristics of sodium and lithium, sodium-ion batteries have attracted widespread attention and are considered a strong competitor to lithium-ion batteries in large-scale energy storage and low-speed electric vehicles. If titanium niobate (TiNb) could be successfully incorporated into the anode material... 24 O 62 The successful application of this material in sodium-ion batteries will have significant value. Summary of the Invention

[0003] This invention aims to at least partially solve one of the technical problems in related technologies. To this end, this invention proposes a sodium-ion battery anode material, its preparation method, and its application.

[0004] In a first aspect, this application provides a sodium-ion battery anode material. According to embodiments of this application, the sodium-ion battery anode material comprises a compound shown in Formula 1:

[0005] TiNb 24-x M x O 62 Formula 1

[0006] M includes at least five of the following: Re, Mo, W, V, Cr, Cu, Ni, Fe, Co, Cu, Zn, Mn, Sn, Bi, K, Mg, Al, Li, Rb, Cs, Ru, Rh, Pd, Ag, In, Ir, and Pb; x is 0.8 to 1.6.

[0007] According to the sodium-ion battery anode material of this application, by introducing multiple metal elements and utilizing their different valence states and ion sizes, the positions of niobium atoms are randomly replaced. By adjusting the temperature and element content, the high-entropy doping configuration and positions are controlled, optimizing the structure of the titanium-niobium oxide, improving its ion transport capacity, and controlling the band structure and vacancy concentration to provide more highly active sites. Therefore, this sodium-ion battery anode material exhibits high specific capacity, high rate capability, and excellent cycle performance.

[0008] According to the embodiments of this application, x can be 0.9 to 1.2. Within the above content range, M can be uniformly doped into the bulk phase of titanium niobium oxide, exhibiting good uniformity and being less prone to problems such as agglomeration and segregation. This is beneficial for sodium-ion battery anode materials to have better sodium storage performance, higher specific capacity, higher rate performance, and better cycle performance.

[0009] According to embodiments of this application, M includes at least one element with a highest valence state below +5 and at least one element with a highest valence state above +5. Specifically, niobium typically exists in the crystal structure of sodium-ion battery anode materials in the form of +5. The doping element M is partly selected from elements with a highest valence state above +5 and partly selected from elements with a highest valence state below +5, which is beneficial for valence balance and for generating vacancies in the crystal structure. This can effectively control the configuration of high-entropy doping, thereby improving ion conduction.

[0010] According to embodiments of this application, M comprises at least five elements in equimolar amounts. This allows for better high-entropy doping, improves the ion transport capacity of the sodium-ion battery anode material, and provides more highly active sites, thus better meeting the requirements for use as a sodium-ion battery anode material.

[0011] According to embodiments of this application, the sodium-ion battery anode material further includes a conductive polymer coating layer, which coats at least a portion of the surface of the compound shown in Formula 1. Introducing a conductive polymer coating onto highly entropy-doped titanium-niobium oxide effectively improves its electronic conductivity and achieves higher structural stability. When used in sodium-ion battery anode materials, it can achieve high specific capacity, high rate capability, and excellent cycle performance.

[0012] According to embodiments of this application, the conductive polymer coating layer comprises at least one of polyaniline, polypyrrole, and poly(3,4-ethylenedioxythiophene). Therefore, the aforementioned polymer exhibits superior conductivity, which is beneficial for improving the electronic conductivity and structural stability of the sodium-ion battery anode material. Furthermore, the material is widely available, readily accessible, and inexpensive, and is easily formed into a film on the surface of the compound shown in Formula 1, making it easy to process.

[0013] According to the embodiments of this application, the thickness of the coating layer is 0.1nm~5nm, specifically 2nm; the mass percentage of carbon element in the sodium-ion battery anode material is 0.2%~0.8%, specifically 0.4%.

[0014] According to embodiments of this application, the sodium-ion battery anode material has a porous structure. This significantly accelerates the transport of sodium ions between particles and crystal domains, resulting in superior electrochemical performance when used as a sodium-ion battery anode material.

[0015] According to embodiments of this application, the porous structure includes mesopores with a pore size of 3 nm to 10 nm. This further accelerates the transport of sodium ions between particles and crystal domains, resulting in better electrochemical performance when used as a negative electrode material for sodium-ion batteries.

[0016] According to embodiments of this application, the sodium-ion battery negative electrode material has a microspherical morphology, and the microspheres have a D... 50 The particle size ranges from 4 μm to 15 μm. Its spherical morphology facilitates sodium ion transport, leading to improved electrochemical performance when used as a negative electrode material in sodium-ion batteries.

[0017] A second aspect of this application provides a method for preparing the aforementioned sodium-ion battery anode material. According to embodiments of this application, the method includes: mixing a carbon source, a titanium source, a niobium source, and an M source with a solvent to obtain a mixed solution; subjecting the mixed solution to a hydrothermal reaction to obtain an intermediate; and calcining the intermediate to obtain the compound shown in Formula 1. This method is simple, convenient, and operates under mild conditions, making it easy to implement.

[0018] In some embodiments, the mass ratio of the carbon source, titanium source, niobium source, and M source can be (0.01~10):(10~30):(400~600):(0.01~20), specifically (3~7):(15~25):(450~550):(5~15). Within the above ratio range, the sodium-ion battery anode material has a structure that is more conducive to ion transport, which can meet the requirements for use as a sodium-ion anode material and can be effectively used as a sodium-ion anode material to improve the performance of sodium-ion batteries.

[0019] According to embodiments of this application, the carbon source may include at least one of glucose, starch, sucrose, and fructose. This facilitates the formation of a porous structure in the sodium-ion battery anode material, and the materials are widely available and relatively inexpensive.

[0020] According to embodiments of this application, the titanium source may include at least one of tetrabutyl titanate and titanium isopropoxide. The niobium source may include at least one of niobium pentachloride and niobium ethoxide. The M source may include compounds soluble in the solvent of at least five elements selected from Re, Mo, W, V, Cr, Cu, Ni, Fe, Co, Cu, Zn, Mn, Sn, Bi, K, Mg, Al, Li, Rb, Cs, Ru, Rh, Pd, Ag, In, Ir, and Pb. In some embodiments, the solvent includes ethanol. This facilitates the reaction, and the materials are readily available and inexpensive.

[0021] According to embodiments of this application, the temperature of the hydrothermal reaction can be 100℃~200℃, specifically 120℃~180℃. Within the above temperature range, the hydrothermal reaction is suitable for proceeding, resulting in a complete and rapid reaction with few side reactions.

[0022] According to embodiments of this application, the heating rate of the hydrothermal reaction is 2℃ / min to 20℃ / min, specifically 5℃ / min to 15℃ / min. This heating rate range allows the sodium-ion battery anode material to have suitable pore size and good uniformity of the doped elements.

[0023] According to an embodiment of this application, the holding time for the hydrothermal reaction is 0.2h to 2h, specifically 0.2h to 1h. This time range allows the hydrothermal reaction to proceed fully without wasting time.

[0024] According to embodiments of this application, the calcination treatment temperature is 300℃~1800℃, specifically 500℃~1200℃. Within this temperature range, it is beneficial to obtain sodium-ion battery anode materials with suitable porous structures and high-entropy doping configurations, thereby achieving better sodium-ion transport performance.

[0025] According to embodiments of this application, the heating rate of the calcination treatment is 10℃ / min to 200℃ / min, specifically 10℃ / min to 200℃ / min. Within this heating rate range, it is beneficial to obtain sodium-ion battery anode materials with better uniformity of doped elements.

[0026] According to an embodiment of this application, the holding time for the calcination treatment is 0.1~2 h, specifically 0.3~1 h. Within this temperature range, the reaction can proceed fully without wasting time due to excessive duration, thus improving efficiency.

[0027] According to embodiments of this application, the method further includes: forming a conductive polymer coating layer on the surface of the compound shown in Formula 1. Introducing a conductive polymer coating onto the sodium-ion battery anode material can effectively improve electron conductivity and achieve higher structural stability. As a sodium-ion battery anode material, it can achieve higher specific capacity, higher rate performance, and excellent cycle performance.

[0028] According to embodiments of this application, forming a conductive polymer coating layer may include: immersing the compound shown in Formula 1 in an aqueous solution of a conductive polymer monomer to obtain a dispersion; adding an initiator to the dispersion and continuously stirring to cause the conductive polymer monomer to undergo a polymerization reaction, thereby forming the conductive polymer coating layer on the surface of the compound shown in Formula 1. Specifically, the conductive polymer monomer can undergo a polymerization reaction under the initiation of the initiator and coat the surface of the compound shown in Formula 1.

[0029] According to embodiments of this application, the concentration of the conductive polymer monomer aqueous solution is 0.1M to 1M, specifically 0.2M to 0.6M. This allows for the acquisition of a conductive polymer coating layer with superior coating effect, effectively improving electronic conductivity and achieving higher structural stability.

[0030] According to embodiments of this application, the polymerization reaction time is 0.5 h to 2 h, specifically 1 h to 1.5 h. Within this time range, a conductive polymer coating layer with better performance can be obtained.

[0031] A third aspect of this application provides a sodium-ion battery anode material. According to embodiments of this application, the sodium-ion battery anode material includes the sodium-ion battery anode material described above, or the sodium-ion battery anode material prepared by the methods described above. Using the sodium-ion battery anode material as a sodium-ion battery anode material can achieve high specific capacity, high rate capability, and excellent cycle performance.

[0032] A fourth aspect of this application provides a sodium-ion battery. According to an embodiment of this application, the sodium-ion battery includes a negative electrode sheet, the negative electrode sheet including a negative electrode material, the negative electrode material including the aforementioned sodium-ion battery negative electrode material. This sodium-ion battery exhibits high specific capacity, high rate capability, and excellent cycle performance.

[0033] A fifth aspect of this application provides an electrical device. According to an embodiment of this application, the electrical device includes the sodium-ion battery described above. This electrical device possesses all the features and advantages of the sodium-ion battery described above, which will not be repeated here. Attached Figure Description

[0034] Figure 1This is a SEM image of the sodium-ion battery anode material obtained in Example 1 of this application.

[0035] Figure 2 This is a SEM image of the sodium-ion battery anode material obtained in Example 8 of this application. Detailed Implementation

[0036] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0037] This application is based on the inventor's following discoveries and understandings:

[0038] The inventors discovered that titanium niobate materials in related technologies have a distinct bulk structure that restricts the diffusion of sodium ions. To improve the sodium storage capacity of titanium niobate, further structural optimization is crucial. At the same time, the inventors noted that high-entropy materials have simple crystal structures of multi-component mixtures (usually five or more equimolar elements) and single-phase solid solutions, providing enormous compositional possibilities for customizing target functions.

[0039] In view of this, in a first aspect, this application provides a sodium-ion battery anode material. According to embodiments of this application, the sodium-ion battery anode material comprises a compound shown in Formula 1:

[0040] TiNb 24-x M x O 62 Formula 1

[0041] M includes at least five of the following: Re, Mo, W, V, Cr, Cu, Ni, Fe, Co, Cu, Zn, Mn, Sn, Bi, K, Mg, Al, Li, Rb, Cs, Ru, Rh, Pd, Ag, In, Ir, and Pb; x is 0.8 to 1.6.

[0042] According to the sodium-ion battery anode material of this application, by introducing multiple metal elements and utilizing their different valence states and ion sizes, the positions of niobium atoms are randomly replaced. By adjusting the temperature and element content, the high-entropy doping configuration and positions are controlled, optimizing the structure of the titanium-niobium oxide, improving its ion transport capacity, and controlling the band structure and vacancy concentration to provide more highly active sites. Therefore, this sodium-ion battery anode material can serve as a sodium-ion battery anode material and exhibits high specific capacity, high rate capability, and excellent cycle performance.

[0043] According to the embodiments of this application, x can be 0.9~1.2, specifically such as 0.9, 0.95, 1.0, 1.05, 1.1, 1.15, 1.2, etc. Within the above content range, M can be uniformly doped into the bulk phase of titanium niobium oxide, exhibiting good uniformity and being less prone to problems such as agglomeration and segregation. This is beneficial for sodium-ion battery anode materials to have better sodium storage performance, resulting in higher specific capacity, higher rate capability, and superior cycle performance when used as sodium-ion battery anode materials.

[0044] According to embodiments of this application, M includes at least one element with a highest valence state below +5 and at least one element with a highest valence state above +5. As an example, elements with a highest valence state above +5 include, but are not limited to, Mo, Re, and W, while elements with a highest valence state below +5 include, but are not limited to, Mg, Cr, Ni, and Cu. Specifically, niobium typically exists in the crystal structure of sodium-ion battery anode materials in the form of a +5 valence state. The doping element M is partially selected from elements with a highest valence state above +5 and partially from elements with a highest valence state below +5, which is beneficial for valence balance and for creating vacancies in the crystal structure. This effectively controls the configuration of high-entropy doping, thereby improving ion conduction.

[0045] According to embodiments of this application, the specific types of metal elements included in M ​​can be 5, 6, 7, 8, 9, etc. The amount of different types of metal elements in M ​​can be selected according to actual needs. As an example, M includes at least 5 elements in equimolar amounts. Taking M as including five metal elements a, b, c, d, and e as an example, equimolar amounts of these five elements mean that the molar ratio of elements a, b, c, d, and e is 1:1:1:1:1. This allows for better achievement of high-entropy doping effects, better improvement of the ion transport capacity of sodium-ion battery anode materials, and provision of more highly active sites, thus better meeting the requirements for use in sodium-ion battery anode materials.

[0046] According to embodiments of this application, the sodium-ion battery anode material further includes a conductive polymer coating layer, which coats at least a portion of the surface of the compound shown in Formula 1. It is understood that the conductive polymer layer may cover only a portion of the surface of the compound shown in Formula 1, or it may cover the entire surface of the compound shown in Formula 1, meaning the conductive polymer layer completely encapsulates the compound shown in Formula 1. As an example, the conductive polymer layer completely coats the compound shown in Formula 1. Thus, by introducing a conductive polymer coating onto highly entropy-doped titanium niobium oxide, its electronic conductivity is effectively improved and higher structural stability is achieved. When used in sodium-ion battery anode materials, it can achieve high specific capacity, high rate capability, and excellent cycle performance.

[0047] According to embodiments of this application, the conductive polymer coating layer comprises at least one of polyaniline, polypyrrole, and poly(3,4-ethylenedioxythiophene). Therefore, the aforementioned polymer exhibits superior conductivity, which is beneficial for improving the electronic conductivity and structural stability of the sodium-ion battery anode material. Furthermore, the material is widely available, readily accessible, and inexpensive, and is easily formed into a film on the surface of the compound shown in Formula 1, making it easy to process.

[0048] According to embodiments of this application, the thickness of the coating layer is 0.1 nm to 5 nm, such as 0.1 nm, 0.5 nm, 1 nm, 1.5 nm, 2 nm, 2.5 nm, 3 nm, 3.5 nm, 4 nm, 4.5 nm, 5 nm, etc. As an example, the thickness of the coating layer can be 2 nm. Within this thickness range, both electronic conductivity and structural stability can be improved, and there are basically no adverse effects.

[0049] According to embodiments of this application, the mass percentage of carbon in the sodium-ion battery anode material is 0.2% to 0.8%, specifically 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, etc. As an example, the mass percentage of carbon in the coating layer can be 0.4%.

[0050] According to embodiments of this application, the sodium-ion battery anode material has a porous structure. This significantly accelerates the transport of sodium ions between particles and crystal domains, resulting in superior electrochemical performance when used as a sodium-ion battery anode material.

[0051] According to embodiments of this application, the porous structure includes mesopores with pore sizes ranging from 3 nm to 10 nm (specifically, 3 nm, 4 nm, 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, etc.). This further accelerates the transport of sodium ions between particles and crystal domains, resulting in better electrochemical performance when used as a negative electrode material for sodium-ion batteries.

[0052] According to embodiments of this application, the sodium-ion battery negative electrode material has a microspherical morphology, and the microspheres have a D... 50 The particle size ranges from 4μm to 15μm, specifically including 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, and 15μm. Its spherical morphology facilitates sodium ion transport, leading to improved electrochemical performance when used as a negative electrode material in sodium-ion batteries.

[0053] In this article, D 50Particle size has a well-known meaning in the art; it represents the particle size corresponding to a material's cumulative volume distribution percentage of 50%, and can be determined using instruments and methods known in the art. For example, it can be determined using a laser particle size analyzer, referring to GB / T 19077-2016. The testing instrument can be, for example, the Mastersizer 3000 laser particle size analyzer from Malvern Instruments Ltd., UK.

[0054] A second aspect of this application provides a method for preparing the aforementioned sodium-ion battery anode material. According to embodiments of this application, the method includes:

[0055] S1: Mix the carbon source, titanium source, niobium source, M source with the solvent to obtain a mixed solution.

[0056] In this step, there are no particular restrictions on the specific operation method for mixing the carbon source, titanium source, niobium source, M source, and solvent, as long as the above raw materials can be mixed and made as uniform as possible. In some embodiments, the carbon source, titanium source, niobium source, and M source can be added to the solvent and then stirred at 300 rpm until completely dissolved to obtain the mixed solution.

[0057] According to embodiments of this application, the ratio of carbon source, titanium source, niobium source, and M source can be determined based on the specific composition of the sodium-ion battery anode material. In some embodiments, the mass ratio of the carbon source, titanium source, niobium source, and M source can be (0.01~10):(10~30):(400~600):(0.01~20), specifically (3~7):(15~25):(450~550):(5~15), for example 0:5:20:500:10, 3:15:450:5, 3:20:500:10, 3:25:550:15, 5:20:500:10, 5:15:550:5, 7:25:450:15, etc. Within the above ratio range, the sodium-ion battery anode material has a structure more conducive to ion transport, which can meet the requirements for use as a sodium-ion anode material, and can be effectively used as a sodium-ion anode material to improve the performance of sodium-ion batteries.

[0058] It is understood that a carbon source may or may not be added in this step, depending on the specific needs. Specifically, the carbon source is oxidized and removed during the calcination step, thereby forming a porous structure in the sodium-ion battery anode material. This plays a crucial role in morphology and particle size control, and in introducing pore structures. According to embodiments of this application, the carbon source may include at least one of glucose, starch, sucrose, and fructose. This facilitates the formation of a porous structure in the sodium-ion battery anode material, and the materials are widely available and relatively inexpensive.

[0059] According to embodiments of this application, the titanium source may include at least one of tetrabutyl titanate and titanium isopropoxide. The niobium source may include at least one of niobium pentachloride and niobium ethoxide. The M source may include compounds soluble in the solvent of at least five elements selected from Re, Mo, W, V, Cr, Cu, Ni, Fe, Co, Cu, Zn, Mn, Sn, Bi, K, Mg, Al, Li, Rb, Cs, Ru, Rh, Pd, Ag, In, Ir, and Pb. This facilitates the reaction, and the materials are readily available and cost-effective.

[0060] According to embodiments of this application, there are no particular limitations on the solvent that can be used in this step, as long as it can effectively dissolve the raw materials and ensure the smooth progress of the reaction. In some embodiments, the solvent includes ethanol.

[0061] S2: The mixed solution is subjected to a hydrothermal reaction to obtain an intermediate.

[0062] In this step, the mixed solution can be added to a reaction vessel (such as a reaction kettle), and then the mixed solution is heated to allow the carbon source, titanium source, niobium source, and M source to react and obtain an intermediate.

[0063] According to embodiments of this application, the temperature of the hydrothermal reaction can be 100℃~200℃, specifically 120℃~180℃, and more specifically 100℃, 110℃, 120℃, 130℃, 140℃, 150℃, 160℃, 170℃, 180℃, 190℃, 200℃, etc. Within the above temperature range, the hydrothermal reaction is suitable for proceeding, resulting in a complete and rapid reaction with few side reactions. If the temperature is too low, the reaction rate will decrease, which is not conducive to a complete reaction or may lead to excessively long reaction times. Conversely, if the reaction temperature is too high, side reactions may increase.

[0064] According to embodiments of this application, the heating rate of the hydrothermal reaction is 2℃ / min to 20℃ / min, specifically 5℃ / min to 15℃ / min, and more specifically 2℃ / min, 5℃ / min, 8℃ / min, 10℃ / min, 12℃ / min, 15℃ / min, 18℃ / min, 20℃ / min, etc. This heating rate range allows the sodium-ion battery anode material to have a suitable pore size and good uniformity of the doped elements. If the heating rate is too low, it may lead to a more complete reaction in the low-temperature region, reducing the pore size, or causing the doped elements to aggregate. If the heating rate is too fast, the equipment requirements become more stringent, which is not conducive to preparation and may increase costs.

[0065] According to the embodiments of this application, the holding time for the hydrothermal reaction is 0.2 h to 2 h, specifically 0.2 h to 1 h, and more specifically 0.2 h, 0.5 h, 0.8 h, 1 h, 1.2 h, 1.5 h, 1.8 h, 2 h, etc. This time range allows the hydrothermal reaction to proceed fully without wasting time.

[0066] It is understood that to obtain an intermediate from the mixture obtained after the hydrothermal reaction, a separation operation is required. This application does not particularly limit the specific separation operation; it can be flexibly selected according to actual needs. For example, the intermediate can be obtained through steps such as filtration, washing, and drying. In some embodiments, after the mixture obtained after the hydrothermal reaction has naturally cooled to room temperature, it can be removed and filtered. Then, it can be washed and filtered alternately with water and anhydrous ethanol until the filtrate is clear and transparent, and the pH of the last drop of filtrate is close to 7. The solid material is then placed in an 80°C oven to dry, obtaining a black solid powder, which is the intermediate.

[0067] S3: The intermediate is calcined to obtain the compound shown in Formula 1.

[0068] In this step, the intermediate can be placed in a crucible and calcined at high temperature to transform it into a sodium-ion battery anode material.

[0069] According to embodiments of this application, the calcination treatment temperature is 300℃~1800℃, specifically 500℃~1200℃, and more specifically 300℃, 400℃, 500℃, 600℃, 700℃, 800℃, 900℃, 1000℃, 1100℃, 1200℃, etc. Within the above temperature range, it is beneficial to obtain sodium-ion battery anode materials with suitable porous structures and high-entropy doping configurations, thereby achieving better sodium-ion transport performance.

[0070] According to the embodiments of this application, the heating rate of the calcination treatment is 10℃ / min to 200℃ / min, specifically 10℃ / min to 200℃ / min, and more specifically 10℃ / min, 20℃ / min, 30℃ / min, 40℃ / min, 50℃ / min, 60℃ / min, 70℃ / min, 80℃ / min, 90℃ / min, 100℃ / min, 110℃ / min, 120℃ / min, 130℃ / min, 140℃ / min, 150℃ / min, 160℃ / min, 170℃ / min, 180℃ / min, 190℃ / min, 200℃ / min, etc. Within the above-mentioned heating rate range, it is beneficial to obtain sodium-ion battery anode materials with better uniformity of doped elements. If the heating rate is too low, the doped elements may aggregate at low temperatures, resulting in relatively poor uniformity of doped elements. If the heating rate is too high, the reaction conditions will be harsh, the equipment requirements will be higher, and the cost may increase.

[0071] According to the embodiments of this application, the holding time for the calcination treatment is 0.1h to 2h, specifically 0.3h to 1h, and more specifically 0.1h, 0.2h, 0.5h, 0.8h, 1h, 1.2h, 1.5h, 1.8h, 2h, etc. Within the above temperature range, the reaction can proceed fully without wasting time due to excessive duration, thus improving efficiency.

[0072] According to embodiments of this application, the method further includes:

[0073] S4: A conductive polymer coating layer is formed on the surface of the compound shown in Formula 1.

[0074] According to embodiments of this application, the introduction of conductive polymer coating on sodium-ion battery anode materials can effectively improve electron conductivity and achieve higher structural stability. As a sodium-ion battery anode material, it can achieve higher specific capacity, higher rate performance, and excellent cycle performance.

[0075] According to embodiments of this application, forming a conductive polymer coating layer may include: immersing the compound shown in Formula 1 in an aqueous solution of a conductive polymer monomer to obtain a dispersion; adding an initiator to the dispersion and continuously stirring to cause the conductive polymer monomer to undergo a polymerization reaction, thereby forming the conductive polymer coating layer on the surface of the compound shown in Formula 1. Specifically, the conductive polymer monomer can undergo a polymerization reaction under the initiation of the initiator and coat the surface of the compound shown in Formula 1.

[0076] According to embodiments of this application, the concentration of the conductive polymer monomer aqueous solution is 0.1M~1M, specifically 0.2M~0.6M, and more specifically 0.1M, 0.2M, 0.3M, 0.4M, 0.5M, 0.6M, etc. This allows for the acquisition of a conductive polymer coating layer with superior coating effect, effectively improving electronic conductivity and achieving higher structural stability. However, if the concentration is too high, excessive growth of the conductive polymer may occur, which is detrimental to improving electronic conductivity, the proportion of active material, and the patency of ion transport channels. Conversely, if the concentration is too low, the coating effect may be poor, with limited improvement in electronic conductivity and structural stability.

[0077] According to embodiments of this application, the polymerization reaction time is 0.5h to 2h, specifically 1h to 1.5h, for example, 0.5h, 0.6h, 0.7h, 0.8h, 0.9h, 1.0h, 1.1h, 1.2h, 1.3h, 1.4h, 1.5h, 1.6h, 1.7h, 1.8h, 1.9h, 2h, etc. Within the above time range, a conductive polymer coating layer with better performance can be obtained.

[0078] It is understandable that after the polymerization reaction is completed, a separation step is required to obtain the target product. In some embodiments, the mixture after the polymerization reaction can be filtered and dried to obtain a sodium-ion battery anode material coated with a conductive polymer coating.

[0079] A third aspect of this application provides a sodium-ion battery anode material. According to embodiments of this application, the sodium-ion battery anode material includes the sodium-ion battery anode material described above, or the sodium-ion battery anode material prepared by the methods described above. Using the sodium-ion battery anode material as a sodium-ion battery anode material can achieve high specific capacity, high rate capability, and excellent cycle performance.

[0080] A fourth aspect of this application provides a sodium-ion battery. According to an embodiment of this application, the sodium-ion battery includes a negative electrode sheet, the negative electrode sheet including a negative electrode material, the negative electrode material including the aforementioned sodium-ion battery negative electrode material. This sodium-ion battery exhibits high specific capacity, high rate capability, and excellent cycle performance.

[0081] It is understood that there are no particular restrictions on the specific type of sodium-ion battery; it can be a primary battery or a secondary battery. The shape of the sodium-ion battery can be cylindrical, square, or any other shape. According to the outer packaging, sodium-ion batteries can be hard-shell batteries, soft-pack batteries, etc.

[0082] Typically, a sodium-ion battery comprises a positive electrode, a negative electrode, an electrolyte, and a separator. The positive electrode, negative electrode, and separator are fabricated into electrode assemblies using winding or stacking processes. The electrode assemblies and electrolyte are housed within an outer package. During the charging and discharging process of a sodium-ion battery, active ions repeatedly insert and extract between the positive and negative electrodes. The electrolyte acts as a conductor of ions between the positive and negative electrodes. The separator, positioned between the positive and negative electrodes, primarily prevents short circuits while allowing ions to pass through.

[0083] The positive electrode in this sodium-ion battery may include a positive current collector and a positive electrode material layer, wherein the positive electrode material layer is disposed on at least one surface of the positive current collector.

[0084] In some embodiments, the positive current collector can be a metal current collector or a composite current collector. For example, metal current collectors include, but are not limited to, aluminum foil current collectors; composite current collectors may include a polymer material substrate and a metal layer formed on at least one surface of the polymer material substrate. Composite current collectors can be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0085] In some embodiments, the positive electrode material layer may include positive electrode active material, binder and conductive agent, and may also include additives with specific functions and effects, such as thickeners, sodium supplements, film-forming additives, flame retardants, high temperature / low temperature stabilizers, etc., as needed.

[0086] As an example, the positive electrode active material of a sodium-ion battery may include one or more of layered oxides, polyanionic compounds, and Prussian blue compounds. For example, layered oxides may include Na... y M'O2, M' = Fe, Mn, Ni, Co, Cr, Sc, Ti, V, Cr, Cu, Zn and their combinations, 0.4 ≤ y ≤ 1, for example NaVO2, NaFeO2, Na 0.7 CoO2, NaNi 1 / 3 Fe 1 / 3 Mn 1 / 3O2, NaFe 0.5 Ni 0.5 O2, Na 0.6 MnO2, Na 0.44 MnO2, Na 0.65 Mn 0.75 Ni 0.25 O2, NaNi 0.5 Mn 0.5 O2, Na0.78 Ni 0.23 Mn 0.69 O2, Na 0.67 Mn 0.67 N i0.33 O2, etc. Polyanionic compounds can include one or more of phosphates, pyrophosphates, sulfate types, and anion-doped types, such as olivine-type NaFePO4, Na2FeP2O7, NaFePO4F, Na3V2(PO4)3, and NaFeSO4. Prussian blue compounds can include Na... 0.61 Fe[Fe(CN)6] 0.94 BR-FeHCF, Na 1.48 Ni[Fe(CN)6] 0.89 NaNi 0.05 Mn 0.95 One or more of [Fe(CN)6].

[0087] As an example, the binder in the positive electrode active material layer may include at least one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resin.

[0088] As an example, the conductive agent in the positive electrode active material layer may include at least one of superconducting carbon, conductive graphite, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0089] In some embodiments, the negative electrode sheet may include a negative electrode current collector and a layer of negative electrode active material disposed on at least one side surface of the negative electrode current collector.

[0090] As an example, the negative electrode active material layer may include a negative electrode active material, a thickener, a conductive agent, and a binder, wherein the negative electrode current collector may be a metal foil, for example, a copper foil. The negative electrode active material may include the sodium-ion battery negative electrode material described above.

[0091] According to embodiments of this application, the binder in the negative electrode material layer may include, but is not limited to, at least one of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethyl methacrylate (PMAA), and carboxymethyl chitosan (CMCS).

[0092] According to embodiments of this application, the conductive agent in the negative electrode material layer may include, but is not limited to, at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0093] In some embodiments, the separator may be a separator known in the art that can be used in sodium-ion batteries and is stable to the electrolyte used, such as a polyethylene separator, a polypropylene separator, a polyethylene / polypropylene composite separator, etc.

[0094] A fifth aspect of this application provides an electrical device. According to an embodiment of this application, the electrical device includes the sodium-ion battery described above. This electrical device possesses all the features and advantages of the sodium-ion battery described above, which will not be repeated here.

[0095] According to embodiments of this application, the specific type of the electrical device is not particularly limited and can be any device that uses a sodium-ion battery as a power source or energy storage unit. As examples, the electrical device includes, but is not limited to, electric vehicles (e.g., pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), mobile terminals (e.g., mobile phones, laptops, game consoles, wearable devices, etc.), drones, aerospace equipment, satellites, ships, energy storage systems, etc. It is understood that, in addition to the battery mentioned above, the electrical device also includes necessary structures and components, all of which can be implemented with reference to conventional technology. For example, an electric vehicle may include a body, chassis, tires, navigation system, radar system, steering system, braking system, lubrication system, cooling system, driving system, etc., which will not be elaborated upon here.

[0096] The embodiments of this application are described in detail below.

[0097] Example 1

[0098] (1) Add starch, tetrabutyl titanate, niobium ethanol, ammonium permanganate, molybdenum pentachloride, nickel dicone, anhydrous copper sulfate, and magnesium sulfate heptahydrate salts to 70 mL of anhydrous ethanol at a mass ratio of 5:20:480:5 and stir at 300 rpm for 40 min until completely dissolved.

[0099] (2) Pour the solution obtained in (1) into a 100 mL reaction vessel. The hydrothermal temperature is 150 °C, the heating rate is 10 °C / min, and the holding time is 0.5 h. Then, let it cool naturally to room temperature, remove it and filter it. Wash and filter it alternately with water and anhydrous ethanol until the filtrate is clear and transparent, and the pH of the last drop of filtrate is close to 7. Place the solid material in an 80 °C oven to dry it and obtain a black solid powder.

[0100] (3) In an air environment, the powder obtained in (2) is evenly spread in a crucible and subjected to high-temperature calcination treatment. The maximum temperature is 800 ℃, the heating rate is 160 ℃ / min, the holding time is 0.5 h, and then it is naturally cooled to room temperature to obtain sodium-ion battery negative electrode material.

[0101] (4) The sodium-ion battery anode material obtained in (3) is immersed in a 0.3 M pyrrole aqueous solution and stirred at 300 rpm to disperse it evenly. Then, a 0.1 M ammonium persulfate solution is slowly added dropwise and stirred continuously for 1 hour. Then, it is taken out and filtered, and washed and filtered alternately with water and anhydrous ethanol until the filtrate is clear and transparent and the pH of the last drop of filtrate is close to 7. The solid material is placed in an 80°C oven to dry, and the polymer-coated sodium-ion battery anode material is obtained.

[0102] The sodium-ion battery anode material obtained in this embodiment exhibits a microspherical morphology (SEM image as shown). Figure 1 ), D of microspheres 50 The particle size is mostly 6μm, and the pore size obtained by gas adsorption-desorption test is mostly mesopores of 3nm~10nm.

[0103] Example 2

[0104] Same as Example 1, except that: a mixture of starch, tetrabutyl titanate, niobium ethanol, ammonium permanganate, molybdenum pentachloride, nickel dicene, anhydrous copper sulfate, and magnesium sulfate heptahydrate salts were added to 70 mL of anhydrous ethanol at a mass ratio of 5:20:480:10 and stirred at 300 rpm for 40 min until completely dissolved.

[0105] Example 3

[0106] Same as Example 1, except that: starch, tetrabutyl titanate, niobium ethanol, zinc acetate, nickel dicone, anhydrous copper sulfate, magnesium sulfate heptahydrate, and potassium acetate salt mixture were added to 70 mL of anhydrous ethanol at a mass ratio of 5:20:480:5 and stirred at 300 rpm for 40 min until completely dissolved.

[0107] Example 4

[0108] Same as Example 1, except that the heating rate in the hydrothermal reaction step is 2 °C / min.

[0109] Example 5

[0110] Same as Example 1, except that the heating rate in the calcination step is 10 °C / min.

[0111] Example 6

[0112] Same as Example 1, except that the highest temperature in the calcination step is 1200℃.

[0113] Example 7

[0114] Same as Example 1, except that the concentration of the pyrrole aqueous solution is 0.6M.

[0115] Example 8

[0116] Same as Example 1, except that: a mixture of tetrabutyl titanate, niobium ethoxide, ammonium rheniumate, molybdenum pentachloride, nickel dicene, anhydrous copper sulfate, and magnesium sulfate heptahydrate salts was added to 70 mL of anhydrous ethanol at a mass ratio of 20:480:5 and stirred at 300 rpm for 40 min until completely dissolved.

[0117] Example 9

[0118] Same as Example 1, except that the polymer coating in step (4) was not performed.

[0119] Comparative Example 1

[0120] Same as Example 1, except that: starch, tetrabutyl titanate, and niobium ethoxide were added to 70 mL of anhydrous ethanol in a mass ratio of 5:20:480, and stirred at 300 rpm for 40 min until completely dissolved.

[0121] Performance testing:

[0122] 1. Elemental Proportion Test: The proportion of metal elements is determined using inductively coupled plasma atomic emission spectrometry (ICP-OES). The specific test steps are as follows: The sample is decomposed / digested to dissolve the metal elements into a clear liquid; the sample to be tested is sprayed to form an aerosol, which is heated by a light source to excite the emitted light. The light intensity is converted into photocurrent, which is processed by the circuit and calculated as the content of the element.

[0123] The mass percentage of carbon content was determined using an organic elemental analyzer. The specific testing steps are as follows: The sodium-ion battery negative electrode material coated with conductive polymer was placed in a high-temperature aerobic environment to burn the organic matter and obtain gaseous oxides of different elements. These oxides were then separated and detected by a chromatographic column to obtain the mass percentage of carbon.

[0124] 2. Pore volume and pore size distribution test: A nitrogen adsorption-desorption instrument was used to perform nitrogen adsorption-desorption test on the sample, and the adsorption-desorption curves were obtained to calculate the pore volume and pore size distribution results.

[0125] 3. Battery Performance Testing: The materials obtained in Examples 1-9 and Comparative Example 1 were used as negative electrode active materials. Negative electrode sheets were prepared with a formulation of negative electrode active material:CMC:SBR:SP = 100:1.5:3:1. Sodium sheets were used as positive electrodes. The electrolyte was 1 M NaPF6 / (EC and DMC volume ratio 1:1). Glass fiber was used as the separator. Button half-cells were assembled in a glove box filled with high-purity argon gas. Electrochemical performance was tested using a Wuhan Landian CT2001A battery tester. The charge / discharge voltage range was controlled between 0 and 3V, and the charge / discharge current densities were 50, 100, 200, 500, 1000, and 2000 mA / g. The test results are summarized in Table 2.

[0126] Table 1: Element Proportion Test Results

[0127]

[0128] As shown in Table 1, the atomic ratios of Ti, Nb, and O in each embodiment and comparative example are very close to 1:24:62, indicating that TiNb was successfully prepared. 24 O 62 In Example 1, the atomic percentage of each dopant element (Re, Mo, Ni, Cu, Mg) was 0.2%, indicating uniform doping of each element. Since the relative percentage of Ti and Nb atoms was slightly higher than 1:24, it is inferred that the dopant elements randomly replaced the positions of niobium atoms. Elemental analysis determined that the polypyrrole coating amount was approximately 0.5 wt.%, and the carbon / nitrogen mass ratio was close to 4:1, indicating that the coating material was polypyrrole.

[0129] Compared with Example 1, increasing the proportion of mixed metal salts in Example 2 resulted in a slight decrease in the uniformity of the raw materials due to the increased concentration.

[0130] Compared with Example 1, in Example 3, after adjusting the M source to Zn\Ni\Cu\Mg\K, the proportion of each metal atom was 0.2%, indicating that uniform doping can still be achieved by using different mixed metal sources.

[0131] Compared with Example 1, in Example 4, the hydrothermal heating rate was reduced to 2 °C / min. The slower hydrothermal heating rate resulted in a more complete reaction in the low-temperature region. On the one hand, this reduced the pore size of the porous microspheres (to 2~7 nm), and on the other hand, it caused the atomic percentages of each dopant element Re, Mo, Ni, Cu, and Mg to deviate significantly from 0.2%. This indicates that the rapid heating in the hydrothermal process helps to reduce the possibility of element aggregation during the low-temperature process and achieve uniform dispersion of the mixed metal elements.

[0132] Compared with Example 1, in Example 5 the heat treatment heating rate was reduced to 10 °C / min. The slower heat treatment heating rate caused the atomic percentages of each dopant element Re, Mo, Ni, Cu and Mg to deviate significantly from 0.2%. This indicates that the rapid heating during the heat treatment process is more conducive to reducing the possibility of element aggregation during low temperature processes and achieving uniform dispersion of mixed metal elements.

[0133] Compared to Example 1, no carbon source was added in Example 8, and the SEM images are as follows. Figure 2 As shown, the particles exhibit an irregular blocky shape and a relatively large particle size (mostly 7-9 μm). The absence of obvious differences on the particle surface indicates a low porosity, suggesting that the carbon source plays a crucial role in spheroidization, particle size control, and the introduction of porous structures. The atomic percentages of Re, Mo, Ni, Cu, and Mg deviate from 0.2%, indicating that the presence of the carbon source facilitates the uniform dispersion of metal elements in the precursor. The decrease in the proportion of carbon and nitrogen to 0.36 wt.% indicates that the larger particle size and lack of porous structure lead to a reduction in the number of coating sites for polypyrrole, resulting in a decrease in coating amount.

[0134] Compared with Example 1, the polymer coating in step (4) was not performed in Example 9, so the carbon and nitrogen content in the resulting material is 0.

[0135] Compared to Example 1, no mixed metal salt was added in Comparative Example 1, resulting in TiNb. 24 O 62 The material contains Ti, Nb, and O in an elemental ratio of 1:24:62, indicating the synthesis of a pure-phase TiNb. 24 O 62 .

[0136] Table 2: Battery Performance Test Results

[0137]

[0138] As can be seen from Table 2, the polymer-coated high-entropy doped TiNb in the embodiments of this application... 24 O 62 The material exhibits superior performance compared to Comparative Example 1, with a first reversible capacity and first coulombic efficiency at a current density of 50 mA / g, a reversible capacity of 328.6 mA h / g at a current density of 2000 mA / g, and a capacity retention of 92.3% after 4000 cycles at a current density of 500 mA / g. This demonstrates that the high-entropy structure of the high-entropy doped titanium-niobium compound in this application helps increase interlayer spacing, modulate band structure, and introduce oxygen vacancies, thereby improving capacity and kinetic performance. The abundant porosity facilitates ion transport and enhances rate performance; while the conductive polymer coating helps improve electron conductivity.

[0139] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0140] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A sodium-ion battery anode material, characterized in that, Including the compounds shown in Formula 1: TiNb 24-x M x O 62 Formula 1 M includes at least five of Re, Mo, W, V, Cr, Cu, Ni, Fe, Co, Cu, Zn, Mn, Sn, Bi, K, Mg, Al, Li, Rb, Cs, Ru, Rh, Pd, Ag, In, Ir, and Pb, and M includes at least one element whose highest valence state is lower than +5 and at least one element whose highest valence state is higher than +5. x ranges from 0.8 to 1.

6.

2. The sodium-ion battery anode material according to claim 1, characterized in that, M includes at least five elements in equimolar amounts.

3. The sodium-ion battery anode material according to claim 1, characterized in that, x ranges from 0.9 to 1.

2.

4. The sodium-ion battery anode material according to claim 1, characterized in that, Also includes: A conductive polymer coating layer, said conductive polymer coating layer covering at least a portion of the surface of the compound shown in Formula 1.

5. The sodium-ion battery anode material according to claim 4, characterized in that, The conductive polymer coating material includes at least one of polyaniline, polypyrrole, and poly(3,4-ethylenedioxythiophene).

6. The sodium-ion battery anode material according to claim 4, characterized in that, At least one of the following conditions must be met: The thickness of the coating layer is 0.1 nm to 5 nm; In the sodium-ion battery anode material, the mass percentage of carbon is 0.2% to 0.8%.

7. The sodium-ion battery anode material according to claim 6, characterized in that, At least one of the following conditions must be met: The thickness of the coating layer is 2 nm; In the sodium-ion battery anode material, the mass percentage of carbon is 0.4%.

8. The sodium-ion battery anode material according to claim 1, characterized in that, The sodium-ion battery anode material has a porous structure and satisfies at least one of the following conditions: The porous structure includes mesopores with a pore size of 3nm to 10nm; The pore volume of the porous structure is 0.01 g / cm³. 3 ~0.6g / cm 3 .

9. The sodium-ion battery anode material according to claim 8, characterized in that, The pore volume of the porous structure is 0.03 g / cm³. 3 .

10. The sodium-ion battery anode material according to claim 1, characterized in that, The sodium-ion battery anode material has a microsphere morphology, and the D50 particle size of the microspheres is 4μm~15μm.

11. A method for preparing the sodium-ion battery anode material according to any one of claims 1 to 10, characterized in that, include: A mixed solution is obtained by mixing carbon source, titanium source, niobium source, M source with solvent; The mixed solution is subjected to a hydrothermal reaction to obtain an intermediate; The intermediate was calcined to obtain the compound shown in Formula 1.

12. The method according to claim 11, characterized in that, At least one of the following conditions must be met: The mass ratio of the carbon source, titanium source, niobium source, and M source is (0.01~10):(10~30):(400~600):(0.01~20). The carbon source includes at least one of glucose, starch, sucrose, and fructose; The titanium source includes at least one of tetrabutyl titanate and titanium isopropoxide; The niobium source includes at least one of niobium pentachloride and niobium ethanol. The M source includes compounds soluble in the solvent of at least five elements selected from Re, Mo, W, V, Cr, Cu, Ni, Fe, Co, Cu, Zn, Mn, Sn, Bi, K, Mg, Al, Li, Rb, Cs, Ru, Rh, Pd, Ag, In, Ir, and Pb. The solvent includes ethanol.

13. The method according to claim 12, characterized in that, The mass ratio of the carbon source, titanium source, niobium source, and M source is (3~7):(15~25):(450~550):(5~15).

14. The method according to claim 11, characterized in that, The hydrothermal reaction satisfies at least one of the following conditions: The temperature of the hydrothermal reaction is 100℃~200℃; The heating rate of the hydrothermal reaction is 2℃ / min to 20℃ / min; The holding time for the hydrothermal reaction is 0.2 h to 2 h.

15. The method according to claim 14, characterized in that, The hydrothermal reaction satisfies at least one of the following conditions: The temperature of the hydrothermal reaction is 120℃~180℃; The heating rate of the hydrothermal reaction is 5℃ / min to 15℃ / min; The holding time for the hydrothermal reaction is 0.2h to 1h.

16. The method according to claim 11, characterized in that, The calcination treatment satisfies at least one of the following conditions: The calcination temperature is 300℃~1800℃; The heating rate of the calcination treatment is 10℃ / min to 200℃ / min; The holding time for the calcination treatment is 0.1h to 2h.

17. The method according to claim 16, characterized in that, The calcination treatment satisfies at least one of the following conditions: The calcination temperature is 500℃~1200℃; The heating rate of the calcination treatment is 10℃ / min to 200℃ / min; The holding time for the calcination treatment is 0.3h to 1h.

18. The method according to any one of claims 11 to 17, characterized in that, Also includes: A conductive polymer coating layer is formed on the surface of the compound shown in Formula 1.

19. The method according to claim 18, characterized in that, Forming the conductive polymer coating layer includes: The compound shown in Formula 1 was immersed in an aqueous solution of a conductive polymer monomer to obtain a dispersion; An initiator is added to the dispersion, and the mixture is continuously stirred to allow the conductive polymer monomers to undergo a polymerization reaction, thereby forming the conductive polymer coating layer on the surface of the compound shown in Formula 1.

20. The method according to claim 19, characterized in that, At least one of the following conditions must be met: The concentration of the aqueous solution of the conductive polymer monomer is 0.1 M to 1 M; The polymerization reaction takes 0.5 h to 2 h.

21. The method according to claim 20, characterized in that, At least one of the following conditions must be met: The concentration of the aqueous solution of the conductive polymer monomer is 0.2 M to 0.6 M; The polymerization reaction takes 1 to 1.5 hours.

22. A sodium-ion battery, characterized in that, The device includes a negative electrode sheet, the negative electrode sheet comprising a negative electrode material, the negative electrode material comprising any one of claims 1 to 10, or a sodium-ion battery negative electrode material prepared by any one of claims 11 to 21.

23. An electrical appliance, characterized in that, Including the sodium-ion battery as described in claim 22.

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