Wide-temperature-range multi-phase interface hetero-nanoflower electrode material, preparation method and application thereof

Abstract

This invention belongs to the field of sodium-ion battery technology, specifically relating to wide-temperature-range multiphase interface heterogeneous nanoflower electrode materials, their preparation methods, and applications. Using dopamine hydrochloride, ammonium molybdate, and iron salts as raw materials, a Mo / Fe / PDA polymer is formed through coordination chelation. This polymer, along with a selenium source, is placed downstream and upstream of a tube furnace, respectively, and carbonized and simultaneously selenized under Ar2 to obtain Fe / FeSe / MoSe2 multiphase interface heterogeneous nanoflowers. This invention uses dopamine as a coordination inducer and carbon source, constructing a three-dimensional carbon network and Fe-FeSe and FeSe-MoSe2 heterogeneous interfaces through one-step calcination, achieving a synergistic effect of rapid kinetic response and stable structural maintenance: a reversible capacity of approximately 130 mAh·g at -16℃. ‑1 ; room temperature 5 A·g ‑1 It still maintains 214.56 mAh·g after 7000 cycles. ‑1 The capacity retention rate reached 89.57% after 300 cycles at 60℃.

Description

Technical Field

[0001] This invention belongs to the field of sodium-ion battery technology, specifically relating to wide-temperature-range multiphase interface heterogeneous nanoflower electrode materials, their preparation methods, and applications. Background Technology

[0002] Molybdenum-based chalcogenides (MoX2, X=S, Se) are considered to be a promising anode material for wide-temperature-range sodium-ion batteries due to their unique layered structure, large interlayer spacing, and high theoretical specific capacity. Scholars at home and abroad have carried out a series of studies on improving their wide-temperature-range electrochemical performance and proposed a variety of modification strategies. Common modification strategies include heterostructure construction, element doping, vacancy / defect engineering, etc.

[0003] Among numerous strategies, constructing heterogeneous interfaces has proven to be an effective one. Due to the difference in Fermi levels between different materials, charges redistribute at the heterogeneous interface, generating an internal electric field. This electric field can directionally drive sodium ion migration like an "ion pump," thereby significantly reducing charge transfer impedance. This is considered one of the core physical mechanisms for improving low-temperature performance. For example, existing technology 1 constructs a MoS2 / MoO3 heterostructure through the spontaneous hydrolysis and oxidation reaction of MoS2 in aqueous solution. It achieves excellent low-temperature sodium storage characteristics by forming an internal electric field through interfacial charge redistribution, coupled with biphasic synergistic buffering of volumetric strain: at an ultra-low temperature of -40℃, with a sodium content of 2 A·g... -1 The current density remains at 303.7 mAh·g after 900 cycles. -1 The capacity retention rate is as high as 92.9% (Zhang Y, Wang X, Shi C, et al. Construction of MoS2 / MoO3 heterostructure with Ultrafast-Charged and Superior Low-Temperature Sodium Storage Properties. ACS Nano2025, 19 (30), 27270-27279.). Prior art 2 prepared a WS2 / MoS2 heterostructure and combined it with a conductive matrix Ti3C2T. x Combined, forming a three-dimensional cross-linked WS2 / MoS2 / Ti3C2T x Materials. The electric field at the heterogeneous interface promotes Na + And electron transport, while alleviating WS2 / MoS2 / Ti3C2T x The material undergoes volume expansion during cycling. Therefore, WS2 / MoS2 / Ti3C2T xThe material exhibits excellent electrochemical performance at −20 °C (Tang S, Yuan Q, Wang J, et al. From 2D to 3D: WS2 / MoS2 heterostructure in-situ anchored on Ti3C2T). x MXene with enhanced ion / electron migration and sodium storage at −20 ℃. Energy Storage Materials 2024, 68, 103357. The above demonstrates the promoting effect of the heterojunction electric field on low-temperature ion transport.

[0004] Elemental doping is another precise control strategy that addresses the electronic structure level. Doped atoms can reconfigure the electronic states of the crystal lattice, giving materials like MoS2 zero band gap characteristics and significantly improving intrinsic conductivity. Simultaneously, the lattice distortion and interlayer spacing expansion induced by doping can optimize the properties of Na. + Diffusion channels are established, and the temperature dependence of the diffusion barrier is reduced by modulating the band shift. More importantly, the active sites formed by doping can stabilize the SEI film and inhibit the decomposition of the electrolyte at high temperatures. For example, existing technology 3 constructs a monolayer Fe-MoS2 / N,O co-doped C overlapping structure by Fe doping, achieving a breakthrough in wide-temperature-range performance: DFT calculations prove that Fe doping can modulate the electronic structure to make MoS2 exhibit zero band gap characteristics, reducing the diffusion barrier of sodium ions; at the same time, the superparamagnetic Fe generated by the conversion reaction... 0 Nanocrystals can induce a strong spin-polarized surface capacitance, allowing the material to maintain a capacitance of 575.7 mAh·g at -40°C. -1 The high capacity of the full cell, and the good cycle stability and rate performance of the full cell in the range of -40℃ to 60℃ (Li Z, Han, M, Wang J, et al. Superparamagnetic Fe Conversion Induces MoS2FastIon Transport in Wide-Temperature-Range Sodium-Ion Batteries. Advanced Functional Materials 2024, 34 (41), 2404263.). In addition, the existing technology 4 modifies 2H-MoS2 by controlling the electronic structure through carbon doping, and uses the extra electrons provided by carbon atoms to occupy the d-phase of 2H-MoS2. x2-y2 / d xyThe modification induces the recombination of Mo 3d orbitals, giving the material the characteristics of the 1T phase, thereby significantly improving conductivity and reaction kinetics. This modified material remains stable at -10℃, successfully overcoming the dual bottlenecks of kinetics and stability under low-temperature conditions (Liu Z, Cai H, Wang F, et al. Carbon Atom Modulation of 2H-MoS2Promotes Sodium Storage Kinetics by a Unique “Intercalation-Conversion” Mechanism). A dvancedEnergy Materials 2024, 14 (34), 2400470.).

[0005] However, the modification strategies reported in the prior art 1-4 all focus on optimizing low-temperature performance over a wide temperature range, paying particular attention to problems such as decreased ion diffusion rate and increased electrode polarization at low temperatures, while neglecting the decline in cycle stability caused by material structure degradation and increased electrolyte side reactions under high-temperature conditions. Summary of the Invention

[0006] The purpose of this invention is to provide a wide-temperature-range multiphase interface heterogeneous nanoflower electrode material, its preparation method, and its application. Dopamine is used as a coordination inducer and carbon source. A Mo / Fe / PDA precursor is formed through coordination chelation, followed by annealing and calcination to obtain a multiphase interface heterostructure (Fe / FeSe / MoSe2) with a nanoflower structure. The two active components, FeSe and MoSe2, are effectively combined with elemental Fe to form abundant heterointerfaces (including Fe-FeSe heterojunctions and FeSe-MoSe2 heterojunctions). The polymerization and coating of dopamine not only provides a rigid framework for the nanoflower morphology, ensuring the structural stability of the precursor during selenization, but also constructs a three-dimensional conductive network around the heterojunction through in-situ carbonization. The precisely controlled selenization process promotes the formation of multiphase interfaces and the synergistic coupling between different phases, thereby achieving both rapid kinetic response and stable structural maintenance over a wide temperature range.

[0007] To achieve the above objectives, the specific technical solution provided by the present invention is as follows: The first objective of this invention is to provide a method for preparing a wide-temperature-range multiphase interface heterogeneous nanoflower electrode material, comprising the following steps: S1. Using dopamine hydrochloride, ammonium molybdate, and trivalent soluble iron salts as raw materials, a coordination chelation reaction is carried out to self-assemble a Mo / Fe / PDA polymer.

[0008] S2. The Mo / Fe / PDA polymer and the selenium source are placed in the corresponding lower and upper temperature zones, respectively, and calcined in an inert atmosphere to perform in-situ carbonization and selenization treatment on the Mo / Fe / PDA polymer. The polydopamine is carbonized to form a nanoflower structure and a Fe / FeSe / MoSe2 multiphase interface heterostructure is formed within the nanoflower structure to obtain a wide-temperature-range multiphase interface heterostructure nanoflower electrode material.

[0009] Furthermore, the molar ratio of dopamine hydrochloride to ammonium molybdate is 1:0.3 to 0.5, and the molar ratio of dopamine hydrochloride to iron ions in the trivalent soluble iron salt is 1:0.1 to 0.2.

[0010] Furthermore, the coordination chelation reaction was carried out at room temperature for 6 to 12 hours.

[0011] Furthermore, the mass ratio of Mo / Fe / PDA polymer to selenium source is 1:1 to 5, and the selenium source is selenium powder.

[0012] Furthermore, the calcination temperature is 600℃~800℃, the heating rate is 2℃ / min~6℃ / min, and the calcination time is 2h~4h.

[0013] Furthermore, the trivalent soluble iron salt is one of ferric chloride hexahydrate, ferric nitrate nonahydrate, ferric sulfate, ferric chloride, and ferric phosphate.

[0014] Furthermore, before the coordination chelation reaction, water and ethanol were used as the solvent system, and the pH was adjusted to 8.0–9.0, with a water to ethanol volume ratio of 1:1.5–2.5.

[0015] The second objective of this invention is to provide a wide-temperature-range multiphase interface heterogeneous nanoflower electrode material, which is prepared using the above-described preparation method.

[0016] The third objective of this invention is to provide the application of the above-mentioned wide-temperature-range multiphase interface heterogeneous nanoflower electrode material in the anode of sodium-ion batteries.

[0017] Furthermore, the sodium-ion battery anode includes a current collector, a conductive material, a binder, and an active material. The binder bonds the conductive material and the active material to the current collector. The active material is the aforementioned wide-temperature-range multiphase interface heterogeneous nanoflower electrode material. The mass ratio of the conductive material, binder, and active material is 1:0.4-0.8:2.8-3.8.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention uses dopamine as a coordination inducer and carbon source to form a Mo / Fe / PDA precursor through coordination chelation. This precursor is then annealed and calcined to obtain a multiphase interfacial heterostructure (Fe / FeSe / MoSe2) with a nanoflower structure. This method effectively combines the two active components, FeSe and MoSe2, with elemental Fe, forming abundant heterointerfaces (including Fe-FeSe heterojunctions and FeSe-MoSe2 heterojunctions). The polymerization and coating of dopamine not only provides a rigid framework for the nanoflower morphology, ensuring the structural stability of the precursor during selenization, but also promotes the formation of multiphase interfaces and synergistic coupling between different phases. Furthermore, in-situ carbonization constructs a three-dimensional conductive network around the heterojunction. The prepared nanoflower structure improves cycling stability, effectively buffers the huge volume expansion during charge and discharge, and solves the problems of easy stacking and pulverization of sheet electrode structures. At the same time, it helps to increase the specific surface area, increase the number of electrochemical reaction active sites, shorten the ion transport path, and optimize reaction kinetics. The formed multiphase interface heterojunction and the pseudocapacitive contribution of Fe nanoparticles improve conductivity, enhance reaction kinetics, accelerate ion / electron transport, and significantly improve the material conductivity, thus achieving both rapid kinetic response and stable structure maintenance over a wide temperature range.

[0019] The Fe / FeSe / MoSe2 multiphase interface heterogeneous nanoflower electrode material prepared in this invention achieves a synergistic improvement in electrochemical kinetics and structural stability over a wide temperature range. Specifically:

[0020] Excellent low-temperature reversible capacity: The electrode material retains approximately 130 mAh·g even at a low temperature of -16°C. -1 The reversible capacity indicates that the built-in electric field induced by the multiphase interface effectively promotes the growth of Na+ at low temperatures. + Interface transmission.

[0021] Excellent long-term cycling stability at room temperature: at room temperature, 5 A·g -1 After 7000 cycles at high current density, it still provides up to 214.56 mAh·g. -1 The discharge specific capacity fully demonstrates the mechanical buffering effect of the nanoflower structure and the protection of electrode integrity by the three-dimensional carbon network.

[0022] Significant high-temperature cycling stability: After 300 cycles at 60℃, the capacity retention rate is as high as 89.57% (discharge specific capacity 300.56 mAh·g). -1In contrast, Comparative Example 1 (pure MoSe2 nanoflowers) exhibited a sharp capacity decay and data anomalies after only 247 cycles under the same test conditions, failing to maintain stable operation. This demonstrates that the present invention effectively suppresses material structure degradation and electrolyte side reactions at high temperatures through the synergistic effect of the Fe / FeSe / MoSe2 multiphase interface and the carbon network.

[0023] In summary, this invention breaks through the bottleneck of performance imbalance in the wide temperature range of existing molybdenum-based chalcogenide anode materials, and truly achieves the unity of high kinetic response and high structural stability in a wide temperature range (-16℃ to 60℃). Attached Figure Description

[0024] Figure 1 This is a microstructure diagram of the Fe / FeSe / MoSe2@NC electrode material prepared in Example 1 of the present invention. Figure 1 In the diagram, a is a scanning electron microscope (SEM) and b is a transmission electron microscope (TEM).

[0025] Figure 2 The image shows the X-ray diffraction pattern of the Fe / FeSe / MoSe2@NC electrode material prepared in Example 1 of this invention.

[0026] Figure 3 The pseudocapacitive contribution diagram is shown for the Fe / FeSe / MoSe2@NC electrode material prepared in Example 1 of this invention.

[0027] Figure 4 This is a diagram showing the high and low temperature cycle performance of the sodium-ion battery of this invention. Figure 4 In the figure, a is the cycling performance of the Fe / FeSe / MoSe2@NC electrode material of Example 1 at different temperatures, and b is the cycling performance of the electrode materials of Example 1 and Comparative Examples 1 to 2 at 60°C.

[0028] Figure 5 The graph shows the room-temperature cycling performance of the Fe / FeSe / MoSe2@NC electrode material prepared in Example 1 of this invention for use in a sodium-ion battery. Detailed Implementation

[0029] To enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be further described below in conjunction with specific embodiments and accompanying drawings. However, the embodiments described are not intended to limit the present invention.

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0031] In the research of sodium-ion battery anode materials, existing technologies have reported a variety of candidate materials, including carbon materials (hard carbon, carbon black, carbon fiber, graphene, etc.), oxides / phosphates, and sodium alloys / composites. Among them, molybdenum selenide (MoSe2) stands out due to its unique layered structure, large interlayer spacing, and high theoretical specific capacity (422 mAh·g). -1 MoSe2 is considered a highly promising anode material. However, existing MoSe2 materials generally suffer from the following technical problems: their layered structure is prone to uncontrolled aggregation and stacking during preparation and cycling, leading to a reduction in effective active sites; simultaneously, their intrinsic conductivity is poor, limiting the rapid transport of electrons, resulting in an actual specific capacity far lower than the theoretical value, and sodium ion diffusion kinetics are slow. More significantly, these problems are exacerbated under wide temperature range conditions (such as low-temperature or high-temperature environments): at low temperatures, the diffusion rate of ions in the bulk phase and at the interface decreases significantly, and electrode polarization intensifies; at high temperatures, the material structure is prone to degradation and side reactions increase, leading to rapid capacity decay and deterioration of cycling stability.

[0032] Therefore, how to controllably prepare a MoSe2-based anode material that possesses high specific capacity, long cycle life, excellent rate performance, and stable operation over a wide temperature range remains a pressing technical challenge in this field. This invention uses dopamine as a coordination inducer and carbon source, and self-assembles a Mo / Fe / PDA precursor through coordination chelation. Subsequently, annealing and calcination yield a multiphase interfacial heterostructure with a nanoflower structure. Specifically:

[0033] A method for preparing a wide-temperature-range multiphase interface heterogeneous nanoflower electrode material includes the following steps: S1. Using dopamine hydrochloride, ammonium molybdate, and trivalent soluble iron salts as raw materials, a coordination chelation reaction is carried out to self-assemble a Mo / Fe / PDA polymer.

[0034] In this invention, the molar ratio of dopamine hydrochloride to ammonium molybdate is 1:0.3 to 0.5, and the molar ratio of dopamine hydrochloride to iron ions in trivalent soluble iron salt is 1:0.1 to 0.2.

[0035] It is understood that the coordination chelation reaction is carried out at room temperature with stirring for 6 to 12 hours. The room temperature mentioned in this invention refers to the indoor temperature, which is generally 15°C to 30°C.

[0036] It is understandable that trivalent soluble iron salts are compounds whose cations are iron ions, including one of the following: ferric chloride hexahydrate (FeCl3·6H2O), ferric nitrate nonahydrate (Fe(NO3)3·9H2O), ferric sulfate (Fe2(SO4)3), ferric chloride (FeCl3), and ferric phosphate (FePO4).

[0037] In this invention, before the coordination chelation reaction, the raw materials need to be dissolved in a solvent and the pH adjusted to 8.0–9.0. Ammonia water is preferred for pH adjustment. The mixture is then stirred at room temperature for 6–12 hours to carry out the coordination chelation reaction. Under the coordination chelation effect of metal ions, dopamine hydrochloride undergoes oxidative self-polymerization, self-assembling into a specific three-dimensional Mo / Fe / PDA ternary polymer. It is understood that after the coordination chelation reaction, the reaction solution needs to be purified by centrifugation, washing, and drying. Deionized water and anhydrous ethanol are used for centrifugation and washing, specifically 2–3 times. Centrifugation conditions: 7000–9000 rpm for 4–6 minutes. The drying temperature is 60°C–80°C, and the drying time is at least 8 hours.

[0038] S2. The Mo / Fe / PDA polymer and the selenium source are placed in the corresponding lower and upper temperature zones, respectively, and calcined in an inert atmosphere to perform in-situ carbonization and selenization treatment on the Mo / Fe / PDA polymer. The polydopamine is carbonized to form a nanoflower structure and a Fe / FeSe / MoSe2 multiphase interface heterostructure is formed within the nanoflower structure to obtain a wide-temperature-range multiphase interface heterostructure nanoflower electrode material.

[0039] In this invention, the mass ratio of Mo / Fe / PDA polymer to selenium source is 1:1 to 5, and the selenium source is selenium powder. The calcination temperature is 600℃ to 800℃, the heating rate is 2℃ / min to 6℃ / min, and the calcination time is 2h to 4h. It is understood that the inert atmosphere is an atmosphere formed by inert gases (helium, neon, argon, etc.), nitrogen, or other protective gases that prevent oxidation by oxygen. The preferred inert atmosphere during calcination is an argon (Ar2) atmosphere.

[0040] It is understood that the present invention uses a tube furnace, placing the Mo / Fe / PDA polymer and the selenium source in the corresponding lower and upper temperature zones, respectively, to ensure that the vapor formed by the evaporation of the selenium source is in full contact with the Mo / Fe / PDA polymer.

[0041] This invention uses dopamine as a coordination inducer and carbon source to form a Mo / Fe / PDA precursor through coordination chelation, followed by annealing and calcination to obtain a multiphase interface heterostructure (Fe / FeSe / MoSe2) with a nanoflower structure. This method effectively combines the two active components, FeSe and MoSe2, with elemental Fe, forming abundant heterointerfaces (including Fe-FeSe heterojunctions and FeSe-MoSe2 heterojunctions). The polymerization and coating of dopamine not only provides a rigid framework for the nanoflower morphology, ensuring the structural stability of the precursor during selenization, but also constructs a three-dimensional conductive network around the heterojunction through in-situ carbonization. The precisely controlled selenization process promotes the formation of multiphase interfaces and the synergistic coupling between different phases. By utilizing nanoflower structures to improve cycle stability, the large volume expansion during charge and discharge processes is effectively buffered, solving the problems of easy stacking and pulverization of sheet electrode structures. At the same time, it is beneficial to increase specific surface area, increase electrochemical reaction active sites, shorten ion transport paths, and optimize reaction kinetics. The formed multiphase interface heterojunction and the pseudocapacitive contribution of Fe nanoparticles improve conductivity, enhance reaction kinetics, accelerate ion / electron transport, and significantly improve the material conductivity, thereby compensating for the performance loss caused by the degradation of the conductive network at high temperatures. It also solves the problems of poor conductivity, slow reaction kinetics, and large volume expansion of molybdenum-based materials when used as anode materials for sodium-ion batteries, thus achieving both rapid kinetic response and stable structure maintenance over a wide temperature range.

[0042] This invention also provides a wide-temperature-range multiphase interface heterogeneous nanoflower electrode material. The wide-temperature-range multiphase interface heterogeneous nanoflower electrode material uses an open, multi-level nanoflower structure as the matrix, supported by a rich Fe / FeSe / MoSe2 heterostructure at the phase interface. Its unique nanoflower morphology, composed of ultrathin nanosheets, effectively increases the contact area with the electrolyte, providing abundant electrochemical active sites and ion transport channels, alleviating volume stress during charge and discharge, and preventing electrode material aggregation. Furthermore, the Fe / FeSe / MoSe2 multiphase interface constructed within the flower structure generates a significant interfacial synergistic effect: First, the construction of the heterojunction induces the formation of a local built-in electric field, accelerating the electron / ion migration rate at the interface and significantly improving the material's conductivity. Second, the multiphase interface can induce a redistribution of interfacial charges, optimizing the adsorption energy of intermediate products, thereby regulating the reversible transformation process of products at different charge and discharge stages and promoting the kinetics of Faraday and pseudocapacitive reactions. In addition, the presence of Fe nanoparticles further promotes pseudocapacitive contributions.

[0043] In this invention, a sodium-ion battery negative electrode current collector, a conductive material, a binder, and an active material are included. The binder bonds the conductive material and the active material to the current collector. The active material is the aforementioned wide-temperature-range multiphase interface heterogeneous nanoflower electrode material. The mass ratio of the conductive material, binder, and active material is 1:0.4-0.8:2.8-3.8. As a preferred embodiment of this invention, the current collector is copper foil, the conductive material is carbon black, and the binder is sodium carboxymethyl cellulose. The conductive material, binder, and negative electrode material are added to a solvent to form a slurry, which is then coated onto the surface of the current collector and dried.

[0044] The following specific examples will provide further explanation.

[0045] Example 1 A method for preparing a wide-temperature-range multiphase interface heterogeneous nanoflower electrode material includes the following steps: S1. Weigh 0.125g dopamine hydrochloride, 0.271g ammonium molybdate and 0.03g trivalent soluble iron salt, dissolve them in 150mL solvent (deionized water and ethanol volume ratio of 1:2), adjust the pH of the solution to 8.5 with ammonia water, stir at room temperature for 8h to obtain the reaction solution, centrifuge the reaction solution with deionized water and anhydrous ethanol at 8000r / min and wash it, repeat twice, and then dry at 70℃ for 10h to obtain the self-assembled Mo / Fe / PDA polymer.

[0046] S2. The Mo / Fe / PDA polymer and selenium (Se) powder were weighed at a mass ratio of 1:2 and placed in different quartz boats. The quartz boat containing Se powder was placed upstream inside the tube furnace, while the quartz boat containing the Mo / Fe / PDA polymer was placed downstream to ensure sufficient contact between the Se vapor and the Mo / Fe / PDA polymer. Under a protective argon atmosphere, the component was heated to 700℃ at a rate of 2℃ / min and calcined for 2 hours. After calcination, it was cooled to room temperature with the furnace to obtain a wide-temperature-range multiphase interface heterogeneous nanoflower electrode material, named Fe / FeSe / MoSe2@NC.

[0047] Example 2 A method for preparing a wide-temperature-range multiphase interface heterogeneous nanoflower electrode material includes the following steps: S1. Weigh 0.1g dopamine hydrochloride, 0.25g ammonium molybdate and 0.02g trivalent soluble iron salt, dissolve them in 100mL solvent (the volume ratio of deionized water and ethanol is 1:1.5), adjust the pH of the solution to 9.0 with ammonia water, stir at room temperature for 6h to obtain the reaction solution, centrifuge the reaction solution with deionized water and anhydrous ethanol at 7500r / min and wash it, repeat twice, and then dry it at 60℃ for 12h to obtain the self-assembled Mo / Fe / PDA polymer.

[0048] S2. The Mo / Fe / PDA polymer and selenium (Se) powder were weighed at a mass ratio of 1:1 and placed in different quartz boats. The quartz boat containing Se powder was placed upstream inside the tube furnace, while the quartz boat containing the Mo / Fe / PDA polymer was placed downstream to ensure sufficient contact between Se vapor and the Mo / Fe / PDA polymer. Under a protective argon atmosphere, the component was heated to 800℃ at a rate of 5℃ / min and calcined for 3 hours. After calcination, it was cooled to room temperature with the furnace to obtain a wide-temperature-range multiphase interface heterogeneous nanoflower electrode material, named Fe / FeSe / MoSe2@NC.

[0049] Example 3 A method for preparing a wide-temperature-range multiphase interface heterogeneous nanoflower electrode material includes the following steps: S1. Weigh 0.15g dopamine hydrochloride, 0.35g ammonium molybdate and 0.04g trivalent soluble iron salt, dissolve them in 200mL solvent (deionized water and ethanol volume ratio of 1:2.5), adjust the pH of the solution to 8.0 with ammonia water, stir at room temperature for 10h to obtain the reaction solution, centrifuge the reaction solution with deionized water and anhydrous ethanol at 8500r / min and wash it, repeat twice, and then dry at 80℃ for 8h to obtain the self-assembled Mo / Fe / PDA polymer.

[0050] S2. The Mo / Fe / PDA polymer and selenium (Se) powder were weighed at a mass ratio of 1:3 and placed in different quartz boats. The quartz boat containing Se powder was placed upstream inside the tube furnace, while the quartz boat containing the Mo / Fe / PDA polymer was placed downstream to ensure sufficient contact between Se vapor and the Mo / Fe / PDA polymer. Under a protective argon atmosphere, the component was heated to 600℃ at a rate of 3℃ / min and calcined for 4 hours. After calcination, it was cooled to room temperature with the furnace to obtain a wide-temperature-range multiphase interface heterogeneous nanoflower electrode material, named Fe / FeSe / MoSe2@NC.

[0051] Comparative Example 1 A method for preparing a MoSe2@NC electrode material includes the following steps: S1. Dissolve 0.125g dopamine hydrochloride and 0.406g ammonium molybdate in 150mL of solvent (deionized water and ethanol in a volume ratio of 1:2). Adjust the pH of the solution to 8.5 with ammonia. Stir at room temperature for 4h to obtain a reaction solution. Centrifuge the reaction solution with deionized water and anhydrous ethanol at 8000r / min and wash it. Repeat twice. Then dry at 80℃ for 12h to obtain a self-assembled Mo / PDA polymer.

[0052] S2. The Mo / PDA polymer and selenium (Se) powder were weighed at a mass ratio of 1:2 and placed in different quartz boats. The quartz boat containing Se powder was placed upstream inside the tube furnace, while the quartz boat containing Mo / PDA polymer was placed downstream to ensure sufficient contact between Se vapor and Mo / PDA polymer. Under a protective argon atmosphere, the component was heated to 700℃ at a rate of 2℃ / min and calcined for 2 hours. After calcination, it was cooled to room temperature with the furnace to obtain the MoSe2@NC electrode material.

[0053] Comparative Example 2 A method for preparing FeSe@NC electrode material includes the following steps: S1. Weigh 0.125g of dopamine hydrochloride and 0.09g of trivalent soluble iron salt, dissolve them in 150mL of solvent (the volume ratio of deionized water and ethanol is 1:2), adjust the pH of the solution to 8.5 with ammonia water, stir at room temperature for 8h to obtain the reaction solution, centrifuge the reaction solution with deionized water and anhydrous ethanol at 8000r / min and wash it, repeat twice, and then dry it at 80℃ for 12h to obtain the self-assembled Fe / PDA polymer.

[0054] S2. Fe / PDA polymer and selenium (Se) powder were weighed at a mass ratio of 1:2 and placed in different quartz boats. The quartz boat containing Se powder was placed upstream inside the tube furnace, while the quartz boat containing Fe / PDA polymer was placed downstream to ensure sufficient contact between Se vapor and Fe / PDA polymer. Under a protective argon atmosphere, the component was heated to 700℃ at a rate of 2℃ / min and calcined for 2 hours. After calcination, it was cooled to room temperature with the furnace to obtain the FeSe@NC electrode material.

[0055] Since the Fe / FeSe / MoSe2@NC electrode materials prepared in Examples 1 to 3 have basically the same structure and similar properties, the Fe / FeSe / MoSe2@NC electrode material prepared in Example 1 was used as the research target for structural testing, and the results are shown below.

[0056] Figure 1 This is a microstructure diagram of the Fe / FeSe / MoSe2@NC electrode material prepared in Example 1 of the present invention. Figure 1 In the diagram, 'a' represents a scanning electron microscope (SEM), and 'b' represents a transmission electron microscope (TEM). Figure 1 As shown, the electrode material is a multiphase interface heterojunction nanoflower electrode material structure. The nanoflower-like morphology is composed of nanosheets, and the phase interface is rich. The Fe / FeSe / MoSe2 heterostructure is loaded on the nanosheets.

[0057] Figure 2 The image shows the X-ray diffraction pattern of the Fe / FeSe / MoSe2@NC electrode material prepared in Example 1 of this invention. Figure 2 As shown, all diffraction peaks correspond well to MoSe. 2、 The presence of FeSe and Fe as the three active components, with no other impurities detected, fully demonstrates that the above steps successfully prepared the Fe / FeSe / MoSe2@NC multiphase interface heterogeneous nanoflower structure.

[0058] Figure 3 This is a pseudocapacitive contribution diagram of the Fe / FeSe / MoSe2@NC electrode material prepared in Example 1 of this invention. Figure 3 It can be seen that 0.7 mV·s -1 At the scan rate, the pseudocapacitance of the Fe / FeSe / MoSe2@NC electrode material accounts for 93.5%.

[0059] The Fe / FeSe / MoSe2@NC electrode material prepared in Example 1, the MoSe2@NC electrode material prepared in Comparative Example 1, and the FeSe@NC electrode material prepared in Comparative Example 2 were used as anodes in sodium-ion batteries. The anodes consisted of copper foil, carbon black, sodium carboxymethyl cellulose, and active materials. Sodium carboxymethyl cellulose bonded the carbon black and active materials to the copper foil. The active materials were Fe / FeSe / MoSe2@NC, MoSe2@NC, or MoSe2@NC electrode materials, with a mass ratio of carbon black, sodium carboxymethyl cellulose, and active materials of 1:0.5:3.5. A slurry was prepared by adding conductive materials, binders, and anode materials to deionized water. This slurry was then coated onto the surface of a current collector and dried to obtain the final product.

[0060] A sodium-ion battery comprises a sodium-ion battery negative electrode, a positive electrode, an electrolyte, and a separator assembled as described above. Specifically, the positive electrode can be metallic sodium. Specifically, the electrolyte in the electrolyte is sodium trifluoromethanesulfonate (NaCF3SO3); the solvent is diethylene glycol dimethyl ether (DIGLYME). Specifically, the separator can be a glass fiber separator.

[0061] Figure 4 This is a diagram showing the high and low temperature cycle performance of the sodium-ion battery of this invention. Figure 4 In the diagram, a represents the cycling performance of the Fe / FeSe / MoSe2@NC electrode material of Example 1 at different temperatures, and b represents the cycling performance of the electrode materials of Example 1 and Comparative Examples 1 to 2 at 60°C. Figure 4 As shown, in 2 A·g -1 At current densities of [value missing], this material exhibits excellent cycling stability over a wide temperature range. Even at -16°C, it retains approximately 130 mAh·g [value missing]. -1 Reversible capacity; after 300 cycles at 60℃, the capacity still reaches 300.56 mAh·g. -1It is significantly superior to the MoSe2@NC electrode material prepared in Comparative Example 1 and the FeSe@NC electrode material prepared in Comparative Example 2, demonstrating good wide-temperature energy storage advantages.

[0062] Figure 5 The graph shows the room-temperature cycling performance of the Fe / FeSe / MoSe2@NC electrode material prepared in Example 1 of this invention in a sodium-ion battery. Figure 5 As shown, the Fe / FeSe / MoSe2@NC electrode material at 5 A·g -1 After 7000 cycles at the current density, it still provides 214.56 mAh·g. −1 High discharge specific capacity.

[0063] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0064] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for preparing a wide-temperature-range multiphase interface heterogeneous nanoflower electrode material, characterized in that, Includes the following steps: Using dopamine hydrochloride, ammonium molybdate, and trivalent soluble iron salts as raw materials, a coordination chelation reaction was carried out to self-assemble a Mo / Fe / PDA polymer. The Mo / Fe / PDA polymer and selenium source were placed in the corresponding lower and upper temperature zones, respectively, and calcined in an inert atmosphere to perform in-situ carbonization and selenization treatment on the Mo / Fe / PDA polymer. Polydopamine carbonization formed a nanoflower structure and Fe / FeSe / MoSe2 multiphase interface heterostructure was formed within the nanoflower structure to obtain a wide-temperature-range multiphase interface heterostructure nanoflower electrode material.

2. The method for preparing the wide-temperature-range multiphase interface heterogeneous nanoflower electrode material according to claim 1, characterized in that, The molar ratio of dopamine hydrochloride to ammonium molybdate is 1:0.3 to 0.5, and the molar ratio of dopamine hydrochloride to iron ions in trivalent soluble iron salt is 1:0.1 to 0.

2.

3. The method for preparing the wide-temperature-range multiphase interface heterogeneous nanoflower electrode material according to claim 1, characterized in that, The coordination chelation reaction was carried out at room temperature for 6 to 12 hours.

4. The method for preparing the wide-temperature-range multiphase interface heterogeneous nanoflower electrode material according to claim 1, characterized in that, The mass ratio of Mo / Fe / PDA polymer to selenium source is 1:1 to 5, and the selenium source is selenium powder.

5. The method for preparing the wide-temperature-range multiphase interface heterogeneous nanoflower electrode material according to claim 1, characterized in that, The calcination temperature is 600℃~800℃, the heating rate is 2℃ / min~6℃ / min, and the calcination time is 2h~4h.

6. The method for preparing the wide-temperature-range multiphase interface heterogeneous nanoflower electrode material according to claim 1, characterized in that, The trivalent soluble iron salt is one of the following: ferric chloride hexahydrate, ferric nitrate nonahydrate, ferric sulfate, ferric chloride, and ferric phosphate.

7. The method for preparing the wide-temperature-range multiphase interface heterogeneous nanoflower electrode material according to claim 1, characterized in that, Before the coordination chelation reaction, water and ethanol were used as the solvent system, and the pH was adjusted to 8.0-9.

0. The volume ratio of water to ethanol was 1:1.5-2.

5.

8. A wide-temperature-range multiphase interface heterogeneous nanoflower electrode material, characterized in that, It is prepared using any one of the preparation methods of claims 1 to 7.

9. The application of the wide-temperature-range multiphase interface heterogeneous nanoflower electrode material as described in claim 8 in the anode of a sodium-ion battery.

10. The application according to claim 9, characterized in that, The sodium-ion battery anode includes a current collector, a conductive material, a binder, and an active material. The binder binds the conductive material and the active material onto the current collector. The active material is the wide-temperature-range multiphase interface heterogeneous nanoflower electrode material as described in claim 8. The mass ratio of the conductive material, the binder, and the active material is 1:0.4-0.8:2.8-3.8.

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